451
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Yamanis TJ, Fisher JC, Moody JW, Kajula LJ. Young Men's Social Network Characteristics and Associations with Sexual Partnership Concurrency in Tanzania. AIDS Behav 2016; 20:1244-55. [PMID: 26271813 DOI: 10.1007/s10461-015-1152-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Social network influence on young people's sexual behavior is understudied in sub-Saharan Africa. Previous research identified networks of mostly young men in Dar es Salaam who socialize in "camps". This study describes network characteristics within camps and their relationship to young men's concurrent sexual partnerships. We conducted surveys with a nearly complete census of ten camp networks (490 men and 160 women). Surveys included name generators to identify camp-based networks. Fifty seven percent of sexually active men (n = 471) reported past year concurrency, measured using the UNAIDS method. In a multivariable model, men's individual concurrency was associated with being a member of a closer knit camp in which concurrency was the normative behavior. Younger men who had older members in their networks were more likely to engage in concurrency. Respondent concurrency was also associated with inequitable personal gender norms. Our findings suggest strategies for leveraging social networks for HIV prevention among young men.
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452
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Li X, LeBlanc J, Elashoff D, McHardy I, Tong M, Roth B, Ippoliti A, Barron G, McGovern D, McDonald K, Newberry R, Graeber T, Horvath S, Goodglick L, Braun J. Microgeographic Proteomic Networks of the Human Colonic Mucosa and Their Association With Inflammatory Bowel Disease. Cell Mol Gastroenterol Hepatol 2016; 2:567-583. [PMID: 28174738 PMCID: PMC5042708 DOI: 10.1016/j.jcmgh.2016.05.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 05/06/2016] [Indexed: 12/28/2022]
Abstract
BACKGROUND & AIMS Interactions between mucosal cell types, environmental stressors, and intestinal microbiota contribute to pathogenesis in inflammatory bowel disease (IBD). Here, we applied metaproteomics of the mucosal-luminal interface to study the disease-related biology of the human colonic mucosa. METHODS We recruited a discovery cohort of 51 IBD and non-IBD subjects endoscopically sampled by mucosal lavage at 6 colonic regions, and a validation cohort of 38 no-IBD subjects. Metaproteome data sets were produced for each sample and analyzed for association with colonic site and disease state using a suite of bioinformatic approaches. Localization of select proteins was determined by immunoblot analysis and immunohistochemistry of human endoscopic biopsy samples. RESULTS Co-occurrence analysis of the discovery cohort metaproteome showed that proteins at the mucosal surface clustered into modules with evidence of differential functional specialization (eg, iron regulation, microbial defense) and cellular origin (eg, epithelial or hemopoietic). These modules, validated in an independent cohort, were differentially associated spatially along the gastrointestinal tract, and 7 modules were associated selectively with non-IBD, ulcerative colitis, and/or Crohn's disease states. In addition, the detailed composition of certain modules was altered in disease vs healthy states. We confirmed the predicted spatial and disease-associated localization of 28 proteins representing 4 different disease-related modules by immunoblot and immunohistochemistry visualization, with evidence for their distribution as millimeter-scale microgeographic mosaic. CONCLUSIONS These findings suggest that the mucosal surface is a microgeographic mosaic of functional networks reflecting the local mucosal ecology, whose compositional differences in disease and healthy samples may provide a unique readout of physiologic and pathologic mucosal states.
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Key Words
- ANOVA, analysis of variance
- CD, Crohn’s disease
- Ecology
- HBD, human β-defensin
- HD5, human alpha defensin 5
- HNP, human neutrophil peptide
- HPLC, high-performance liquid chromatography
- IBD, inflammatory bowel disease
- IHC, immunohistochemistry
- Inflammatory Bowel Disease
- MALDI, matrix-assisted laser desorption/ionization
- MFN, mucosal functional network
- MLI, mucosal–luminal interface
- MS/MS, tandem mass spectrometry
- Metaproteomics
- Mucosal
- NLME, nonlinear mixed-effect model
- Networks
- PVCA, principal variance component analysis
- TOF, time of flight
- UC, ulcerative colitis
- WGCNA, weighted correlation network analysis
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Affiliation(s)
- Xiaoxiao Li
- Department of Molecular and Medical Pharmacology, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California,Department of Pathology and Laboratory Medicine, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California,Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - James LeBlanc
- Department of Pathology and Laboratory Medicine, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California
| | - David Elashoff
- Department of Medicine, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California
| | - Ian McHardy
- Department of Pathology and Laboratory Medicine, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California
| | - Maomeng Tong
- Department of Molecular and Medical Pharmacology, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California
| | - Bennett Roth
- Department of Medicine, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California
| | - Andrew Ippoliti
- Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Gildardo Barron
- Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Dermot McGovern
- Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Keely McDonald
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Rodney Newberry
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Thomas Graeber
- Department of Molecular and Medical Pharmacology, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California
| | - Steve Horvath
- Department of Human Genetics and Biostatistics, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California
| | - Lee Goodglick
- Department of Pathology and Laboratory Medicine, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California
| | - Jonathan Braun
- Department of Molecular and Medical Pharmacology, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California,Department of Pathology and Laboratory Medicine, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California,Correspondence Address correspondence to: Jonathan Braun, MD, PhD, Department of Pathology and Laboratory Medicine, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California 90095. fax: (310) 267-4486.Department of Pathology and Laboratory Medicine, University of California Los Angeles David Geffen School of MedicineLos AngelesCalifornia 90095
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453
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Wong SM, Ibrahim GM, Ochi A, Otsubo H, Rutka JT, Snead OC, Doesburg SM. moviEEG: An animation toolbox for visualization of intracranial electroencephalography synchronization dynamics. Clin Neurophysiol 2016; 127:2370-8. [PMID: 27178855 DOI: 10.1016/j.clinph.2016.03.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 03/01/2016] [Accepted: 03/03/2016] [Indexed: 11/29/2022]
Abstract
OBJECTIVE We introduce and describe the functions of moviEEG (Multiple Overlay Visualizations for Intracranial ElectroEncephaloGraphy), a novel MATLAB-based toolbox for spatiotemporal mapping of network synchronization dynamics in intracranial electroencephalography (iEEG) data. METHODS The toolbox integrates visualizations of inter-electrode phase-locking relationships in peri-ictal epileptogenic networks with signal spectral properties and graph-theoretical network measures overlaid upon operating room images of the electrode grid. Functional connectivity between every electrode pair is evaluated over a sliding window indexed by phase synchrony. RESULTS Two case studies are presented to provide preliminary evidence for the application of the toolbox to guide network-based mapping of epileptogenic cortex and to distinguish these regions from eloquent brain networks. In both cases, epileptogenic cortex was visually distinct. CONCLUSION We introduce moviEEG, a novel toolbox for animation of oscillatory network dynamics in iEEG data, and provide two case studies showing preliminary evidence for utility of the toolbox in delineating the epileptogenic zone. SIGNIFICANCE Despite evidence that atypical network synchronization has shown to be altered in epileptogenic brain regions, network based techniques have yet to be incorporated into clinical pre-surgical mapping. moviEEG provides a set of functions to enable easy visualization with network based techniques.
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Affiliation(s)
- Simeon M Wong
- Faculty of Applied Science and Engineering, University of Toronto, Canada; Neuroscience & Mental Health Program, Hospital for Sick Children Research Institute, Canada; Department of Diagnostic Imaging, Hospital for Sick Children, Canada.
| | - George M Ibrahim
- Division of Neurosurgery, Hospital for Sick Children, Canada; Institute of Medical Science, University of Toronto, Canada
| | - Ayako Ochi
- Division of Neurology, Hospital for Sick Children, Canada
| | - Hiroshi Otsubo
- Division of Neurology, Hospital for Sick Children, Canada
| | - James T Rutka
- Division of Neurosurgery, Hospital for Sick Children, Canada
| | - O Carter Snead
- Neuroscience & Mental Health Program, Hospital for Sick Children Research Institute, Canada; Institute of Medical Science, University of Toronto, Canada; Division of Neurology, Hospital for Sick Children, Canada
| | - Sam M Doesburg
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Canada
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454
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Kostuj T, Kladny B, Hoffmann R. [Registries of the German Society for Orthopaedics and Trauma : Overview and perspectives of the DGU and DGOOC registries]. Unfallchirurg 2016; 119:463-8. [PMID: 27174132 DOI: 10.1007/s00113-016-0169-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The register network of the German Society for Orthopaedics and Trauma (DGOU) consists of 14 registries that cover the various fields of traumatology and elective orthopedics. In addition to registries that focus on implants and types of diseases without age limitations, there are also registries dealing with special diseases in children and adolescents as well as the special needs of elderly patients with fractures. The registries serve as instruments for outcome research and quality assurance and can be used to develop treatment recommendations on a high level of evidence. The objective of the network is to exchange experience that facilitates the establishment of new registers, to pool expertise and to conserve resources.
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Affiliation(s)
- T Kostuj
- Klinik für Orthopädie und Unfallchirurgie, Katholisches Krankenhaus Bochum, St. Josef-Hospital Universitätsklinikum der Ruhr-Universität Bochum, Gudrunstraße 56, 44791, Bochum, Deutschland.
| | - B Kladny
- DGOOC, DGOU, Berlin, Deutschland
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455
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Zugasti O, Thakur N, Belougne J, Squiban B, Kurz CL, Soulé J, Omi S, Tichit L, Pujol N, Ewbank JJ. A quantitative genome-wide RNAi screen in C. elegans for antifungal innate immunity genes. BMC Biol 2016; 14:35. [PMID: 27129311 PMCID: PMC4850687 DOI: 10.1186/s12915-016-0256-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/18/2016] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Caenorhabditis elegans has emerged over the last decade as a useful model for the study of innate immunity. Its infection with the pathogenic fungus Drechmeria coniospora leads to the rapid up-regulation in the epidermis of genes encoding antimicrobial peptides. The molecular basis of antimicrobial peptide gene regulation has been previously characterized through forward genetic screens. Reverse genetics, based on RNAi, provide a complementary approach to dissect the worm's immune defenses. RESULTS We report here the full results of a quantitative whole-genome RNAi screen in C. elegans for genes involved in regulating antimicrobial peptide gene expression. The results will be a valuable resource for those contemplating similar RNAi-based screens and also reveal the limitations of such an approach. We present several strategies, including a comprehensive class clustering method, to overcome these limitations and which allowed us to characterize the different steps of the interaction between C. elegans and the fungus D. coniospora, leading to a complete description of the MAPK pathway central to innate immunity in C. elegans. The results further revealed a cross-tissue signaling, triggered by mitochondrial dysfunction in the intestine, that suppresses antimicrobial peptide gene expression in the nematode epidermis. CONCLUSIONS Overall, our results provide an unprecedented system's level insight into the regulation of C. elegans innate immunity. They represent a significant contribution to our understanding of host defenses and will lead to a better comprehension of the function and evolution of animal innate immunity.
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Affiliation(s)
- Olivier Zugasti
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288, Marseille, France
- Present address: Institut de Biologie du Développement de Marseille, CNRS, UMR6216, Case 907, Marseille, France
| | - Nishant Thakur
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288, Marseille, France
| | - Jérôme Belougne
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288, Marseille, France
| | - Barbara Squiban
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288, Marseille, France
- Present address: Section of Hematology/Oncology, Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - C Léopold Kurz
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288, Marseille, France
- Present address: Institut de Biologie du Développement de Marseille, CNRS, UMR6216, Case 907, Marseille, France
| | - Julien Soulé
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288, Marseille, France
- Present address: Institut de Genomique Fonctionnelle, 141, rue de la Cardonille, 34094, Montpellier Cedex 05, France
| | - Shizue Omi
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288, Marseille, France
| | - Laurent Tichit
- Institut de Mathématiques de Marseille, Aix Marseille Université, I2M Centrale Marseille, CNRS UMR 7373, 13453, Marseille, France
| | - Nathalie Pujol
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288, Marseille, France.
| | - Jonathan J Ewbank
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288, Marseille, France.
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456
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Schneider DM, Martins AB, de Aguiar MAM. The mutation-drift balance in spatially structured populations. J Theor Biol 2016; 402:9-17. [PMID: 27132184 DOI: 10.1016/j.jtbi.2016.04.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 02/22/2016] [Accepted: 04/18/2016] [Indexed: 11/17/2022]
Abstract
In finite populations the action of neutral mutations is balanced by genetic drift, leading to a stationary distribution of alleles that displays a transition between two different behaviors. For small mutation rates most individuals will carry the same allele at equilibrium, whereas for high mutation rates of the alleles will be randomly distributed with frequencies close to one half for a biallelic gene. For well-mixed haploid populations the mutation threshold is μc=1/2N, where N is the population size. In this paper we study how spatial structure affects this mutation threshold. Specifically, we study the stationary allele distribution for populations placed on regular networks where connected nodes represent potential mating partners. We show that the mutation threshold is sensitive to spatial structure only if the number of potential mates is very small. In this limit, the mutation threshold decreases substantially, increasing the diversity of the population at considerably low mutation rates. Defining kc as the degree of the network for which the mutation threshold drops to half of its value in well-mixed populations we show that kc grows slowly as a function of the population size, following a power law. Our calculations and simulations are based on the Moran model and on a mapping between the Moran model with mutations and the voter model with opinion makers.
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Affiliation(s)
- David M Schneider
- Instituto de Física 'Gleb Wataghin', Universidade Estadual de Campinas, Unicamp 13083-970, Campinas, SP, Brazil
| | - Ayana B Martins
- Instituto de Física 'Gleb Wataghin', Universidade Estadual de Campinas, Unicamp 13083-970, Campinas, SP, Brazil
| | - Marcus A M de Aguiar
- Instituto de Física 'Gleb Wataghin', Universidade Estadual de Campinas, Unicamp 13083-970, Campinas, SP, Brazil
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457
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Najafi M, McMenamin BW, Simon JZ, Pessoa L. Overlapping communities reveal rich structure in large-scale brain networks during rest and task conditions. Neuroimage 2016; 135:92-106. [PMID: 27129758 DOI: 10.1016/j.neuroimage.2016.04.054] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 04/03/2016] [Accepted: 04/24/2016] [Indexed: 12/16/2022] Open
Abstract
Large-scale analysis of functional MRI data has revealed that brain regions can be grouped into stable "networks" or communities. In many instances, the communities are characterized as relatively disjoint. Although recent work indicates that brain regions may participate in multiple communities (for example, hub regions), the extent of community overlap is poorly understood. To address these issues, here we investigated large-scale brain networks based on "rest" and task human functional MRI data by employing a mixed-membership Bayesian model that allows each brain region to belong to all communities simultaneously with varying membership strengths. The approach allowed us to 1) compare the structure of disjoint and overlapping communities; 2) determine the relationship between functional diversity (how diverse is a region's functional activation repertoire) and membership diversity (how diverse is a region's affiliation to communities); 3) characterize overlapping community structure; 4) characterize the degree of non-modularity in brain networks; 5) study the distribution of "bridges", including bottleneck and hub bridges. Our findings revealed the existence of dense community overlap that was not limited to "special" hubs. Furthermore, the findings revealed important differences between community organization during rest and during specific task states. Overall, we suggest that dense overlapping communities are well suited to capture the flexible and task dependent mapping between brain regions and their functions.
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Affiliation(s)
- Mahshid Najafi
- Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, USA; Department of Psychology, University of Maryland, College Park, MD 20742, USA.
| | - Brenton W McMenamin
- Department of Psychology, University of Maryland, College Park, MD 20742, USA
| | - Jonathan Z Simon
- Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, USA; Department of Biology, University of Maryland, College Park, MD 20742, USA; Institute for Systems Research, University of Maryland, College Park, MD 20742, USA
| | - Luiz Pessoa
- Department of Psychology, University of Maryland, College Park, MD 20742, USA.
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458
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Zhu L, Lei AH, Zheng HY, Lyu LB, Zhang ZG, Zheng YT. Longitudinal analysis reveals characteristically high proportions of bacterial vaginosis-associated bacteria and temporal variability of vaginal microbiota in northern pig-tailed macaques (Macaca leonina). Dongwuxue Yanjiu 2016; 36:285-98. [PMID: 26452693 DOI: 10.13918/j.issn.2095-8137.2015.5.285] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The complex and dynamic vaginal microbial ecosystem is critical to both health and disease of the host. Studies focusing on how vaginal microbiota influences HIV-1 infection may face limitations in selecting proper animal models. Given that northern pig-tailed macaques (Macaca leonina) are susceptible to HIV-1 infection, they may be an optimal animal model for elucidating the mechanisms by which vaginal microbiota contributes to resistance and susceptibility to HIV-1 infection. However, little is known about the composition and temporal variability of vaginal microbiota of the northern pig-tailed macaque. Here, we present a comprehensive catalog of the composition and temporal dynamics of vaginal microbiota of two healthy northern pig-tailed macaques over 19 weeks using 454-pyrosequencing of 16S rRNA genes. We found remarkably high proportions of a diverse array of anaerobic bacteria associated with bacterial vaginosis. Atopobium and Sneathia were dominant genera, and interestingly, we demonstrated the presence of Lactobacillus-dominated vaginal microbiota. Moreover, longitudinal analysis demonstrated that the temporal dynamics of the vaginal microbiota were considerably individualized. Finally, network analysis revealed that vaginal pH may influence the temporal dynamics of the vaginal microbiota, suggesting that inter-subject variability of vaginal bacterial communities could be mirrored in inter-subject variation in correlation profiles of species with each other and with vaginal pH over time. Our results suggest that the northern pig-tailed macaque could be an ideal animal model for prospective investigation of the mechanisms by which vaginal microbiota influence susceptibility and resistance to HIV-1 infection in the context of highly polymicrobial and Lactobacillus-dominated states.
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Affiliation(s)
- Lin Zhu
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming Yunnan 650223, China;Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming Yunnan 650204, China
| | - Ai-Hua Lei
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming Yunnan 650223, China;Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming Yunnan 650204, China
| | - Hong-Yi Zheng
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming Yunnan 650223, China;School of Life Sciences, University of Science and Technology of China, Hefei Anhui 230026, China
| | - Long-Bao Lyu
- Kunming Primate Research Center, Chinese Academy of Sciences, Kunming Yunnan 650223, China
| | - Zhi-Gang Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming Yunnan 650223, China.
| | - Yong-Tang Zheng
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming Yunnan 650223, China;Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming Yunnan 650204, China;Kunming Primate Research Center, Chinese Academy of Sciences, Kunming Yunnan 650223,
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459
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Shiffman J, Quissell K, Schmitz HP, Pelletier DL, Smith SL, Berlan D, Gneiting U, Van Slyke D, Mergel I, Rodriguez M, Walt G. A framework on the emergence and effectiveness of global health networks. Health Policy Plan 2016; 31 Suppl 1:i3-16. [PMID: 26318679 PMCID: PMC4954553 DOI: 10.1093/heapol/czu046] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/27/2014] [Indexed: 12/18/2022] Open
Abstract
Since 1990 mortality and morbidity decline has been more extensive for some conditions prevalent in low- and middle-income countries than for others. One reason may be differences in the effectiveness of global health networks, which have proliferated in recent years. Some may be more capable than others in attracting attention to a condition, in generating funding, in developing interventions and in convincing national governments to adopt policies. This article introduces a supplement on the emergence and effectiveness of global health networks. The supplement examines networks concerned with six global health problems: tuberculosis (TB), pneumonia, tobacco use, alcohol harm, maternal mortality and newborn deaths. This article presents a conceptual framework delineating factors that may shape why networks crystallize more easily surrounding some issues than others, and once formed, why some are better able than others to shape policy and public health outcomes. All supplement papers draw on this framework. The framework consists of 10 factors in three categories: (1) features of the networks and actors that comprise them, including leadership, governance arrangements, network composition and framing strategies; (2) conditions in the global policy environment, including potential allies and opponents, funding availability and global expectations concerning which issues should be prioritized; (3) and characteristics of the issue, including severity, tractability and affected groups. The article also explains the design of the project, which is grounded in comparison of networks surrounding three matched issues: TB and pneumonia, tobacco use and alcohol harm, and maternal and newborn survival. Despite similar burden and issue characteristics, there has been considerably greater policy traction for the first in each pair. The supplement articles aim to explain the role of networks in shaping these differences, and collectively represent the first comparative effort to understand the emergence and effectiveness of global health networks.
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Affiliation(s)
| | | | | | | | | | - David Berlan
- Florida State University, Tallahassee, FL 32306, USA
| | | | | | - Ines Mergel
- Syracuse University, Syracuse, NY 13244, USA
| | | | - Gill Walt
- London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
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460
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Abstract
PURPOSE Network diffusion depends on both the pattern and timing of relations, but the relative effects of timing and structure remain unclear. Here, we first show that concurrency (relations that overlap in time) increases epidemic potential by opening new routes in the network. Because this is substantively similar to adding contact paths, we next compare the effects of concurrency by observed levels of path redundancy (structural cohesion) to determine how the features interact. METHODS We establish that concurrency increases exposure analytically and then use simulation methods to manipulate concurrency over observed networks that vary naturally on structural cohesion. This design allows us to compare networks across a wide concurrency range holding constant features that might otherwise conflate concurrency and cohesion. We summarize the simulation results with general linear models. RESULTS Our results indicate interdependent effects of concurrency and structural cohesion: although both increase epidemic potential, concurrency matters most when the graph structure is sparse, because the exposure created by concurrency is redundant to observed paths within structurally cohesive networks. CONCLUSIONS Concurrency works by opening new paths in temporally ordered networks. Because this is substantively similar to having additional observed paths, concurrency in sparse networks has the same effect as adding relations and will have the greatest effect on epidemic potential in sparse networks.
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Affiliation(s)
- James Moody
- Department of Sociology, Duke University, Durham, NC; King Abdulaziz University, Jeddah, Makkah, Saudi Arabia.
| | - Richard A Benton
- School of Labor & Employment Relations, University of Illinois at Urbana Champaign, Champaign, IL
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461
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Larson JM. The evolutionary advantage of limited network knowledge. J Theor Biol 2016; 398:43-51. [PMID: 27012517 DOI: 10.1016/j.jtbi.2016.03.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 02/02/2016] [Accepted: 03/11/2016] [Indexed: 11/23/2022]
Abstract
Groups of individuals have social networks that structure interactions within the groups; evolutionary theory increasingly uses this fact to explain the emergence of cooperation (Eshel and Cavalli-Sforza, 1982; Boyd and Richerson, 1988, 1989; Ohtsuki et al., 2006; Nowak et al., 2010; Van Veelen et al., 2012). This approach has resulted in a number of important insights for the evolution of cooperation in the biological and social sciences, but omits a key function of social networks that has persisted throughout recent evolutionary history (Apicella et al., 2012): their role in transmitting gossip about behavior within a group. Accounting for this well-established role of social networks among rational agents in a setting of indirect reciprocity not only shows a new mechanism by which the structure of networks is fitness-relevant, but also reveals that knowledge of social networks can be fitness-relevant as well. When groups enforce cooperation by sanctioning peers whom gossip reveals to have deviated, individuals in certain peripheral network positions are tempting targets of uncooperative behavior because gossip they share about misbehavior spreads slowly through the network. The ability to identify these individuals creates incentives to behave uncooperatively. Consequently, groups comprised of individuals who knew precise information about their social networks would be at a fitness disadvantage relative to groups of individuals with a coarser knowledge of their networks. Empirical work has consistently shown that modern humans know little about the structure of their own social networks and perform poorly when tasked with learning new ones. This robust empirical regularity may be the product of natural selection in an environment of strong selective pressure at the group level. Imprecise views of networks make enforcing cooperation easier.
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462
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Morgan E, Skaathun B, Michaels S, Young L, Khanna A, Friedman SR, Davis B, Pitrak D, Schneider J; UConnect Study Team. Marijuana Use as a Sex-Drug is Associated with HIV Risk Among Black MSM and Their Network. AIDS Behav 2016; 20:600-7. [PMID: 26400079 DOI: 10.1007/s10461-015-1195-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Black men who have sex with men (BMSM) are highest risk for HIV seroconversion in the United States. Little attention has been paid to marijuana use among BMSM and potential for HIV risk. A sample of 202 BMSM was generated through respondent driven sampling. The relationship between differential marijuana use and both HIV risk behavior and social network factors were examined using weighted logistic regression. Of the BMSM in this sample 60.4 % use marijuana in general and 20.8 % use marijuana as sex-drug. General marijuana use was significantly associated with participation in group sex (AOR 3.50; 95 % CI 1.10-11.10) while marijuana use as a sex drug was significantly associated with both participation in condomless sex (AOR 2.86; 95% CI 1.07-7.67) and group sex (AOR 3.39; 95% CI 1.03-11.22). Respondents with a moderate or high perception of network members who use marijuana were more likely to use marijuana both in general and as a sex-drug. Network member marijuana use, while not associated with risk behaviors, is associated with individual marijuana use and individual marijuana use in the context of sex is associated with risk practices. Targeting interventions towards individuals and their respective networks that use marijuana as a sex drug may reduce HIV risk.
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463
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Verhülsdonk S, Supprian T, Höft B. [Geriatric psychiatric home counseling for people with dementia and anosognosia : Results of a model project]. Z Gerontol Geriatr 2016; 50:219-225. [PMID: 26779708 DOI: 10.1007/s00391-015-1018-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 11/30/2015] [Accepted: 12/22/2015] [Indexed: 11/25/2022]
Abstract
BACKGROUND Lack of awareness of an illness (anosognosia) is a common symptom in dementia and has a significant impact on the course of the disease. It is associated with dysfunctional interaction with caregivers. Due to unawareness patients are not able to accept diagnostic procedures or medical treatment and refuse any kind of support. Thus, they are not integrated into psychosocial networks and medical support. This has a significant impact on patient-centered care in a domestic environment. In this article a model project with home visits to patients with dementia and anosognosia is described. METHOD A total of 55 home visits were carried out. The aim of this project was the integration into the existing healthcare services in order to safeguard the domestic environment. These visits focused on advice and information for the patients and their caregivers initiating the visits. Sociodemographic data of the patient cohort and the satisfaction of the caregiving relatives and general practitioners are presented. RESULTS Subjects with dementia were found to be in advanced stages of the disease, caring situations were complex and required assistance. Caregivers showed a substantial burden in accordance with previous reports. CONCLUSION New strategies are required to cope with anosognosia in patients with dementia and their caregivers. Even single home visits seem to be sufficient to initiate support for subjects with dementia and their relatives.
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Affiliation(s)
- Sandra Verhülsdonk
- Institutsambulanz Gerontopsychiatrie, LVR-Klinikum Düsseldorf, Kliniken der Heinrich-Heine-Universität, Mooren Str. 5, Gebäude 14.99, 40225, Düsseldorf, Deutschland.
| | - T Supprian
- Institutsambulanz Gerontopsychiatrie, LVR-Klinikum Düsseldorf, Kliniken der Heinrich-Heine-Universität, Mooren Str. 5, Gebäude 14.99, 40225, Düsseldorf, Deutschland
| | - B Höft
- Institutsambulanz Gerontopsychiatrie, LVR-Klinikum Düsseldorf, Kliniken der Heinrich-Heine-Universität, Mooren Str. 5, Gebäude 14.99, 40225, Düsseldorf, Deutschland
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464
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Kirwan P, Turner-Bridger B, Peter M, Momoh A, Arambepola D, Robinson HPC, Livesey FJ. Development and function of human cerebral cortex neural networks from pluripotent stem cells in vitro. Development 2016; 142:3178-87. [PMID: 26395144 PMCID: PMC4582178 DOI: 10.1242/dev.123851] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A key aspect of nervous system development, including that of the cerebral cortex, is the formation of higher-order neural networks. Developing neural networks undergo several phases with distinct activity patterns in vivo, which are thought to prune and fine-tune network connectivity. We report here that human pluripotent stem cell (hPSC)-derived cerebral cortex neurons form large-scale networks that reflect those found in the developing cerebral cortex in vivo. Synchronised oscillatory networks develop in a highly stereotyped pattern over several weeks in culture. An initial phase of increasing frequency of oscillations is followed by a phase of decreasing frequency, before giving rise to non-synchronous, ordered activity patterns. hPSC-derived cortical neural networks are excitatory, driven by activation of AMPA- and NMDA-type glutamate receptors, and can undergo NMDA-receptor-mediated plasticity. Investigating single neuron connectivity within PSC-derived cultures, using rabies-based trans-synaptic tracing, we found two broad classes of neuronal connectivity: most neurons have small numbers (<10) of presynaptic inputs, whereas a small set of hub-like neurons have large numbers of synaptic connections (>40). These data demonstrate that the formation of hPSC-derived cortical networks mimics in vivo cortical network development and function, demonstrating the utility of in vitro systems for mechanistic studies of human forebrain neural network biology. Summary: Human PSC-derived cerebral cortex neurons form large-scale functional networks that change over time and mimic those found in the developing cerebral cortex in vivo.
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Affiliation(s)
- Peter Kirwan
- Wellcome Trust/CRUK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Benita Turner-Bridger
- Wellcome Trust/CRUK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Manuel Peter
- Wellcome Trust/CRUK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Ayiba Momoh
- Wellcome Trust/CRUK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Devika Arambepola
- Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Hugh P C Robinson
- Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Frederick J Livesey
- Wellcome Trust/CRUK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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465
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Abstract
Existing clinical outcomes of disease activity, including relapse rates, are inherently insensitive to the underlying pathological process in MS. Moreover, it is extremely difficult to measure clinical disability in patients, which is often a retrospective assessment, and definitely not within the time frame of a clinical trial. Biomarkers , conversely are more specific for a pathologic process and if used correctly can prove invaluable in the diagnosis, stratification and monitoring of disease activity, including any subclinical activity which is not visible to the naked eye. In this chapter, we discuss the development of neurofilaments as surrogate outcomes of disability in MS. The validation and qualification are vital steps in biomarker development and to gaining acceptance in scientific community, and the pitfalls leading up to this are also discussed.
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466
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Mvubu NE, Pillay B, Gamieldien J, Bishai W, Pillay M. Canonical pathways, networks and transcriptional factor regulation by clinical strains of Mycobacterium tuberculosis in pulmonary alveolar epithelial cells. Tuberculosis (Edinb) 2015; 97:73-85. [PMID: 26980499 DOI: 10.1016/j.tube.2015.12.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 11/30/2015] [Accepted: 12/10/2015] [Indexed: 12/12/2022]
Abstract
Limited knowledge exists on pathways, networks and transcriptional factors regulated within epithelial cells by diverse Mycobacterium tuberculosis genotypes. This study aimed to elucidate these mechanisms induced in A549 epithelial cells by dominant clinical strains in KwaZulu-Natal, South Africa. RNA for sequencing was extracted from epithelial cells at 48 h post-infection with 5 strains at a multiplicity of infection of approximately 10:1. Bioinformatics analysis performed with the RNA-Seq Tuxedo pipeline identified differentially expressed genes. Changes in pathways, networks and transcriptional factors were identified using Ingenuity Pathway Analysis (IPA). The interferon signalling and hepatic fibrosis/hepatic stellate cell activation pathways were among the top 5 canonical pathways in all strains. Hierarchical clustering for enrichment of cholesterol biosynthesis and immune associated pathways revealed similar patterns for Beijing and Unique; F15/LAM4/KZN and F11; and, F28 and H37Rv strains, respectively. However, the induction of top scoring networks varied among the strains. Among the transcriptional factors, only EHL, IRF7, PML, STAT1, STAT2 and VDR were induced by all clinical strains. Activation of the different pathways, networks and transcriptional factors revealed in the current study may be an underlying mechanism that results in the differential host response by clinical strains of M. tuberculosis.
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Affiliation(s)
- Nontobeko E Mvubu
- School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Westville 3630, South Africa.
| | - Balakrishna Pillay
- School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Westville 3630, South Africa.
| | - Junaid Gamieldien
- South African National Bioinformatics Institute/MRC Unit for Bioinformatics Capacity Development, University of the Western Cape, Bellville 7530, South Africa.
| | - William Bishai
- Department of Medicine, Division of Infectious Diseases, Johns Hopkins School of Medicine, 1550 Orleans St., Baltimore, MD, United State of America.
| | - Manormoney Pillay
- Medical Microbiology and Infection Control, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, 719 Umbilo Road, Private Bag 7, Congella 4013, Durban, South Africa.
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467
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Betzel RF, Fukushima M, He Y, Zuo XN, Sporns O. Dynamic fluctuations coincide with periods of high and low modularity in resting-state functional brain networks. Neuroimage 2015; 127:287-297. [PMID: 26687667 DOI: 10.1016/j.neuroimage.2015.12.001] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 10/30/2015] [Accepted: 12/05/2015] [Indexed: 12/18/2022] Open
Abstract
We investigate the relationship of resting-state fMRI functional connectivity estimated over long periods of time with time-varying functional connectivity estimated over shorter time intervals. We show that using Pearson's correlation to estimate functional connectivity implies that the range of fluctuations of functional connections over short time-scales is subject to statistical constraints imposed by their connectivity strength over longer scales. We present a method for estimating time-varying functional connectivity that is designed to mitigate this issue and allows us to identify episodes where functional connections are unexpectedly strong or weak. We apply this method to data recorded from N=80 participants, and show that the number of unexpectedly strong/weak connections fluctuates over time, and that these variations coincide with intermittent periods of high and low modularity in time-varying functional connectivity. We also find that during periods of relative quiescence regions associated with default mode network tend to join communities with attentional, control, and primary sensory systems. In contrast, during periods where many connections are unexpectedly strong/weak, default mode regions dissociate and form distinct modules. Finally, we go on to show that, while all functional connections can at times manifest stronger (more positively correlated) or weaker (more negatively correlated) than expected, a small number of connections, mostly within the visual and somatomotor networks, do so a disproportional number of times. Our statistical approach allows the detection of functional connections that fluctuate more or less than expected based on their long-time averages and may be of use in future studies characterizing the spatio-temporal patterns of time-varying functional connectivity.
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Affiliation(s)
- Richard F Betzel
- School of Engineering and Applied Science, Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA; Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA.
| | - Makoto Fukushima
- Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Ye He
- Key Laboratory of Behavioral Science and Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Xi-Nian Zuo
- Key Laboratory of Behavioral Science and Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Olaf Sporns
- Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA; Network Science Institute, Indiana University, Bloomington, IN, 47405, USA
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468
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Moorman DE, James MH, McGlinchey EM, Aston-Jones G. Differential roles of medial prefrontal subregions in the regulation of drug seeking. Brain Res 2015; 1628:130-46. [PMID: 25529632 PMCID: PMC4472631 DOI: 10.1016/j.brainres.2014.12.024] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 12/09/2014] [Indexed: 01/08/2023]
Abstract
The prefrontal cortex plays an important role in shaping cognition and behavior. Many studies have shown that medial prefrontal cortex (mPFC) plays a key role in seeking, extinction, and reinstatement of cocaine seeking in rodent models of relapse. Subregions of mPFC appear to play distinct roles in these behaviors, such that the prelimbic cortex (PL) is proposed to drive cocaine seeking and the infralimbic cortex (IL) is proposed to suppress cocaine seeking after extinction. This dichotomy of mPFC function may be a general attribute, as similar dorsal-ventral distinctions exist for expression vs. extinction of fear conditioning. However, other results indicate that the role of mPFC neurons in reward processing is more complex than a simple PL-seek vs. IL-extinguish dichotomy. Both PL and IL have been shown to drive and inhibit drug seeking (and other types of behaviors) depending on a range of factors including the behavioral context, the drug-history of the animal, and the type of drug investigated. This heterogeneity of findings may reflect multiple subcircuits within each of these PFC areas supporting unique functions. It may also reflect the fact that the mPFC plays a multifaceted role in shaping cognition and behavior, including those overlapping with cocaine seeking and extinction. Here we discuss research leading to the hypothesis that dorsal and ventral mPFC differentially control drug seeking and extinction. We also present recent results calling the absolute nature of a PL vs. IL dichotomy into question. Finally, we consider alternate functions for mPFC that correspond less to response execution and inhibition and instead incorporate the complex cognitive behavior for which the mPFC is broadly appreciated.
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Affiliation(s)
- David E Moorman
- Department of Psychological and Brain Sciences & Neuroscience and Behavior Graduate Program, University of Massachusetts Amherst, Amherst, MA 01003, United States.
| | - Morgan H James
- Brain Health Institute, Rutgers University, Piscataway, NJ 08854, United States
| | - Ellen M McGlinchey
- Brain Health Institute, Rutgers University, Piscataway, NJ 08854, United States; Program in Neurosciences, Medical University of South Carolina, Charleston, SC 29425, United States
| | - Gary Aston-Jones
- Brain Health Institute, Rutgers University, Piscataway, NJ 08854, United States
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469
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Prestage G, Brown G, De Wit J, Bavinton B, Fairley C, Maycock B, Batrouney C, Keen P, Down I, Hammoud M, Zablotska I. Understanding Gay Community Subcultures: Implications for HIV Prevention. AIDS Behav 2015; 19:2224-33. [PMID: 25711301 DOI: 10.1007/s10461-015-1027-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Gay and bisexual men (GBM) who participate in gay community subcultures have different profiles, including differing risk behaviors. We examined men's participation in gay community subcultures, and its association with risk behavior. In a cross-sectional survey, 849 GBM provided information about men in their personal networks. We devised measures of their participation in five subcultural groupings and explored their associations with sexual behavior. We identified five subcultural groupings: sexually adventurous; bear tribes; alternative queer; party scene; and sexually conservative. Higher scores on the sexually adventurous measure was associated with being older, having more gay friends, being HIV-positive, and being more sexually active. It was also independently associated with unprotected anal intercourse with casual partners (AOR 1.82; 95 % CI 1.20-2.76; p = 0.005). HIV prevention strategies need to account for the different subcultural groupings in which GBM participate. Measures of engagement with gay subcultures are useful indicators of differential rates of risk behavior and modes of participation in gay community life. Men in more sexually adventurous subcultures are more likely to engage in sexual risk behavior.
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Affiliation(s)
- Garrett Prestage
- Kirby Institute, University of New South Wales, Kensington, NSW, 2052, Australia.
- Australian Research Centre in Sex Health and Society, La Trobe University, 215 Franklin Street, Melbourne, 3000, Australia.
| | - Graham Brown
- Australian Research Centre in Sex Health and Society, La Trobe University, 215 Franklin Street, Melbourne, 3000, Australia.
- Western Australian Centre for Health Promotion Research, Curtin University, Perth, Australia.
| | - John De Wit
- Centre for Social Research in Health, University of New South Wales, Kensington, NSW, 2052, Australia.
| | - Benjamin Bavinton
- Kirby Institute, University of New South Wales, Kensington, NSW, 2052, Australia.
| | | | - Bruce Maycock
- Western Australian Centre for Health Promotion Research, Curtin University, Perth, Australia.
| | - Colin Batrouney
- Victorian AIDS Council/Gay Men's Health Centre, Melbourne, Australia.
| | - Phillip Keen
- Kirby Institute, University of New South Wales, Kensington, NSW, 2052, Australia.
| | - Ian Down
- Kirby Institute, University of New South Wales, Kensington, NSW, 2052, Australia.
| | - Mohamed Hammoud
- Kirby Institute, University of New South Wales, Kensington, NSW, 2052, Australia.
| | - Iryna Zablotska
- Kirby Institute, University of New South Wales, Kensington, NSW, 2052, Australia.
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470
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Wang Z, Andrews MA, Wu ZX, Wang L, Bauch CT. Coupled disease-behavior dynamics on complex networks: A review. Phys Life Rev 2015; 15:1-29. [PMID: 26211717 PMCID: PMC7105224 DOI: 10.1016/j.plrev.2015.07.006] [Citation(s) in RCA: 224] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 06/24/2015] [Accepted: 06/25/2015] [Indexed: 01/30/2023]
Abstract
It is increasingly recognized that a key component of successful infection control efforts is understanding the complex, two-way interaction between disease dynamics and human behavioral and social dynamics. Human behavior such as contact precautions and social distancing clearly influence disease prevalence, but disease prevalence can in turn alter human behavior, forming a coupled, nonlinear system. Moreover, in many cases, the spatial structure of the population cannot be ignored, such that social and behavioral processes and/or transmission of infection must be represented with complex networks. Research on studying coupled disease-behavior dynamics in complex networks in particular is growing rapidly, and frequently makes use of analysis methods and concepts from statistical physics. Here, we review some of the growing literature in this area. We contrast network-based approaches to homogeneous-mixing approaches, point out how their predictions differ, and describe the rich and often surprising behavior of disease-behavior dynamics on complex networks, and compare them to processes in statistical physics. We discuss how these models can capture the dynamics that characterize many real-world scenarios, thereby suggesting ways that policy makers can better design effective prevention strategies. We also describe the growing sources of digital data that are facilitating research in this area. Finally, we suggest pitfalls which might be faced by researchers in the field, and we suggest several ways in which the field could move forward in the coming years.
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Affiliation(s)
- Zhen Wang
- School of Automation, Northwestern Polytechnical University, Xi'an 710072, China; Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka, 816-8580, Japan.
| | - Michael A Andrews
- Department of Mathematics and Statistics, University of Guelph, Guelph, ON, N1G 2W1, Canada.
| | - Zhi-Xi Wu
- Institute of Computational Physics and Complex Systems, Lanzhou University, Lanzhou, Gansu 730000, China.
| | - Lin Wang
- School of Computer and Communication Engineering, Tianjin University of Technology, Tianjin 300384, China.
| | - Chris T Bauch
- Department of Applied Mathematics, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
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471
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Abstract
Relational data are often represented as a square matrix, the entries of which record the relationships between pairs of objects. Many statistical methods for the analysis of such data assume some degree of similarity or dependence between objects in terms of the way they relate to each other. However, formal tests for such dependence have not been developed. We provide a test for such dependence using the framework of the matrix normal model, a type of multivariate normal distribution parameterized in terms of row- and column-specific covariance matrices. We develop a likelihood ratio test (LRT) for row and column dependence based on the observation of a single relational data matrix. We obtain a reference distribution for the LRT statistic, thereby providing an exact test for the presence of row or column correlations in a square relational data matrix. Additionally, we provide extensions of the test to accommodate common features of such data, such as undefined diagonal entries, a non-zero mean, multiple observations, and deviations from normality. Supplementary materials for this article are available online.
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Affiliation(s)
| | - Peter D Hoff
- Departments of Statistics and Biostatistics, University of Washington
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472
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Valba OV, Nechaev SK, Sterken MG, Snoek LB, Kammenga JE, Vasieva OO. On predicting regulatory genes by analysis of functional networks in C. elegans. BioData Min 2015; 8:33. [PMID: 26535058 PMCID: PMC4631084 DOI: 10.1186/s13040-015-0066-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 10/20/2015] [Indexed: 12/14/2022] Open
Abstract
Background Connectivity networks, which reflect multiple interactions between genes and proteins, possess not only a descriptive but also a predictive value, as new connections can be extrapolated and tested by means of computational analysis. Integration of different types of connectivity data (such as co-expression and genetic interactions) in one network has proven to benefit ‘guilt by association’ analysis. However predictive values of connectives of different types, that had their specific functional meaning and topological characteristics were not obvious, and have been addressed in this analysis. Methods eQTL data for 3 experimental C.elegans age groups were retrieved from WormQTL. WormNet has been used to obtain pair-wise gene interactions. The Shortest Path Function (SPF) has been adopted for statistical validation of the co-expressed gene clusters and for computational prediction of their potential gene expression regulators from a network context. A new SPF-based algorithm has been applied to genetic interactions sub-networks adjacent to the clusters of co-expressed genes for ranking the most likely gene expression regulators causal to eQTLs. Results We have demonstrated that known co-expression and genetic interactions between C. elegans genes can be complementary in predicting gene expression regulators. Several algorithms were compared in respect to their predictive potential in different network connectivity contexts. We found that genes associated with eQTLs are highly clustered in a C. elegans co-expression sub-network, and their adjacent genetic interactions provide the optimal functional connectivity environment for application of the new SPF-based algorithm. It was successfully tested in the reverse-prediction analysis on groups of genes with known regulators and applied to co-expressed genes and experimentally observed expression quantitative trait loci (eQTLs). Conclusions This analysis demonstrates differences in topology and connectivity of co-expression and genetic interactions sub-networks in WormNet. The modularity of less continuous genetic interaction network does not correspond to modularity of the dense network comprised by gene co-expression interactions. However the genetic interaction network can be used much more efficiently with the SPF method in prediction of potential regulators of gene expression. The developed method can be used for validation of functional significance of suggested eQTLs and a discovery of new regulatory modules.
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Affiliation(s)
- Olga V Valba
- Laboratory of Nematology, Wageningen University, Wageninge, Netherlands
| | - Sergei K Nechaev
- LPTMS, Université Paris Sud, Orsay Cedex, France ; National Research University, Higher School of Economics, Moscow, Russia
| | - Mark G Sterken
- LPTMS, Université Paris Sud, Orsay Cedex, France ; National Research University, Higher School of Economics, Moscow, Russia ; P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow, Russia
| | - L Basten Snoek
- Laboratory of Nematology, Wageningen University, Wageninge, Netherlands
| | - Jan E Kammenga
- Laboratory of Nematology, Wageningen University, Wageninge, Netherlands
| | - Olga O Vasieva
- Laboratory of Nematology, Wageningen University, Wageninge, Netherlands
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473
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Kaye J, Muddyman D, Smee C, Kennedy K, Bell J. 'Pop-Up' Governance: developing internal governance frameworks for consortia: the example of UK10K. Life Sci Soc Policy 2015; 11:10. [PMID: 26412243 PMCID: PMC4584211 DOI: 10.1186/s40504-015-0028-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/15/2015] [Indexed: 06/05/2023]
Abstract
Innovations in information technologies have facilitated the development of new styles of research networks and forms of governance. This is evident in genomics where increasingly, research is carried out by large, interdisciplinary consortia focussing on a specific research endeavour. The UK10K project is an example of a human genomics consortium funded to provide insights into the genomics of rare conditions, and establish a community resource from generated sequence data. To achieve its objectives according to the agreed timetable, the UK10K project established an internal governance system to expedite the research and to deal with the complex issues that arose. The project's governance structure exemplifies a new form of network governance called 'pop-up' governance. 'Pop-up' because: it was put together quickly, existed for a specific period, was designed for a specific purpose, and was dismantled easily on project completion. In this paper, we use UK10K to describe how 'pop-up' governance works on the ground and how relational, hierarchical and contractual governance mechanisms are used in this new form of network governance.
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Affiliation(s)
- Jane Kaye
- HeLEX Centre, Nuffield Department of Population Health, University of Oxford, Oxford, UK.
- Nuffield Department of Population Health, HeLEX - Centre for Health, Law and Emerging Technologies, University of Oxford, Old Road Campus, Oxford, OX3 7LF, UK.
| | | | - Carol Smee
- Wellcome Trust Sanger Institute, Cambridge, UK
| | | | - Jessica Bell
- HeLEX Centre, Nuffield Department of Population Health, University of Oxford, Oxford, UK
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474
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Sakurai T, Gamo NJ, Hikida T, Kim SH, Murai T, Tomoda T, Sawa A. Converging models of schizophrenia--Network alterations of prefrontal cortex underlying cognitive impairments. Prog Neurobiol 2015; 134:178-201. [PMID: 26408506 DOI: 10.1016/j.pneurobio.2015.09.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 09/10/2015] [Accepted: 09/17/2015] [Indexed: 02/08/2023]
Abstract
The prefrontal cortex (PFC) and its connections with other brain areas are crucial for cognitive function. Cognitive impairments are one of the core symptoms associated with schizophrenia, and manifest even before the onset of the disorder. Altered neural networks involving PFC contribute to cognitive impairments in schizophrenia. Both genetic and environmental risk factors affect the development of the local circuitry within PFC as well as development of broader brain networks, and make the system vulnerable to further insults during adolescence, leading to the onset of the disorder in young adulthood. Since spared cognitive functions correlate with functional outcome and prognosis, a better understanding of the mechanisms underlying cognitive impairments will have important implications for novel therapeutics for schizophrenia focusing on cognitive functions. Multidisciplinary approaches, from basic neuroscience to clinical studies, are required to link molecules, circuitry, networks, and behavioral phenotypes. Close interactions among such fields by sharing a common language on connectomes, behavioral readouts, and other concepts are crucial for this goal.
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475
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Braithwaite J. Bridging gaps to promote networked care between teams and groups in health delivery systems: a systematic review of non-health literature. BMJ Open 2015; 5:e006567. [PMID: 26408280 PMCID: PMC4593159 DOI: 10.1136/bmjopen-2014-006567] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 07/06/2015] [Accepted: 08/27/2015] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVES To assess non-health literature, identify key strategies in promoting more networked teams and groups, apply external ideas to healthcare, and build a model based on these strategies. DESIGN A systematic review of the literature outside of healthcare. METHOD Searches guided by Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) of ABI/INFORM Global, CINAHL, IBSS, MEDLINE and Psychinfo databases following a mind-mapping exercise generating key terms centred on the core construct of gaps across organisational social structures that uncovered 842 empirical articles of which 116 met the inclusion criteria. Data extraction and content analysis via data mining techniques were performed on these articles. RESULTS The research involved subjects in 40 countries, with 32 studies enrolling participants in multiple countries. There were 40 studies conducted wholly or partly in the USA, 46 wholly or partly in continental Europe, 29 wholly or partly in Asia and 12 wholly or partly in Russia or Russian federated countries. Methods employed included 30 mixed or triangulated social science study designs, 39 qualitative studies, 13 experimental studies and 34 questionnaire-based studies, where the latter was mostly to gather data for social network analyses. Four recurring factors underpin a model for promoting networked behaviours and fortifying cross-group cooperation: appreciating the characteristics and nature of gaps between groups; using the leverage of boundary-spanners to bridge two or more groups; applying various mechanisms to stimulate interactive relationships; and mobilising those who can exert positive external influences to promote connections while minimising the impact of those who exacerbate divides. CONCLUSIONS The literature assessed is rich and varied. An evidence-oriented model and strategies for promoting more networked systems are now available for application to healthcare. While caution needs to be exercised in translating outside ideas and studies, drawing on non-health ideas is useful in providing insights into other sectors.
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Affiliation(s)
- Jeffrey Braithwaite
- Australian Institute of Health Innovation, Centre for Healthcare Resilience and Implementation Science, Macquarie University, Sydney, New South Wales, Australia
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476
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Bernhardt BC, Bonilha L, Gross DW. Network analysis for a network disorder: The emerging role of graph theory in the study of epilepsy. Epilepsy Behav 2015; 50:162-70. [PMID: 26159729 DOI: 10.1016/j.yebeh.2015.06.005] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 06/03/2015] [Accepted: 06/04/2015] [Indexed: 01/01/2023]
Abstract
Recent years have witnessed a paradigm shift in the study and conceptualization of epilepsy, which is increasingly understood as a network-level disorder. An emblematic case is temporal lobe epilepsy (TLE), the most common drug-resistant epilepsy that is electroclinically defined as a focal epilepsy and pathologically associated with hippocampal sclerosis. In this review, we will summarize histopathological, electrophysiological, and neuroimaging evidence supporting the concept that the substrate of TLE is not limited to the hippocampus alone, but rather is broadly distributed across multiple brain regions and interconnecting white matter pathways. We will introduce basic concepts of graph theory, a formalism to quantify topological properties of complex systems that has recently been widely applied to study networks derived from brain imaging and electrophysiology. We will discuss converging graph theoretical evidence indicating that networks in TLE show marked shifts in their overall topology, providing insight into the neurobiology of TLE as a network-level disorder. Our review will conclude by discussing methodological challenges and future clinical applications of this powerful analytical approach.
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Affiliation(s)
- Boris C Bernhardt
- Neuroimaging of Epilepsy Laboratory, Brain Imaging Center, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada; Department of Social Neuroscience, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
| | - Leonardo Bonilha
- Department of Neurology, Medical University of South Carolina, SC, USA
| | - Donald W Gross
- Division of Neurology, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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477
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Korczyn AD, Schachter SC, Amlerova J, Bialer M, van Emde Boas W, Brázdil M, Brodtkorb E, Engel J, Gotman J, Komárek V, Leppik IE, Marusic P, Meletti S, Metternich B, Moulin CJA, Muhlert N, Mula M, Nakken KO, Picard F, Schulze-Bonhage A, Theodore W, Wolf P, Zeman A, Rektor I. Third International Congress on Epilepsy, Brain and Mind: Part 1. Epilepsy Behav 2015; 50:116-37. [PMID: 26276417 PMCID: PMC5256665 DOI: 10.1016/j.yebeh.2015.06.044] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/24/2015] [Indexed: 12/12/2022]
Abstract
Epilepsy is both a disease of the brain and the mind. Here, we present the first of two papers with extended summaries of selected presentations of the Third International Congress on Epilepsy, Brain and Mind (April 3-5, 2014; Brno, Czech Republic). Epilepsy in history and the arts and its relationships with religion were discussed, as were overviews of epilepsy and relevant aspects of social cognition, handedness, accelerated forgetting and autobiographical amnesia, and large-scale brain networks.
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Affiliation(s)
- Amos D Korczyn
- Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Israel
| | - Steven C Schachter
- Consortia for Improving Medicine with Innovation and Technology, Harvard Medical School, Boston, MA, USA.
| | - Jana Amlerova
- Department of Neurology, Charles University, 2nd Faculty of Medicine, Motol University Hospital, Prague, Czech Republic
| | - Meir Bialer
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Walter van Emde Boas
- Department of EEG, Dutch Epilepsy Clinics Foundation (SEIN), Heemstede, The Netherlands; Epilepsy Monitoring Unit, Dutch Epilepsy Clinics Foundation (SEIN), Heemstede, The Netherlands
| | - Milan Brázdil
- Masaryk University, Brno Epilepsy Center, St. Anne's Hospital and School of Medicine, Brno, Czech Republic; Central European Institute of Technology (CEITEC), Brno, Czech Republic
| | - Eylert Brodtkorb
- Department of Neurology and Clinical Neurophysiology, St. Olav's Hospital, Trondheim University Hospital, Trondheim, Norway; Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway
| | | | - Jean Gotman
- Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Vladmir Komárek
- Department of Paediatric Neurology, Charles University, 2nd Faculty of Medicine, Motol University Hospital, Prague, Czech Republic
| | - Ilo E Leppik
- MINCEP Epilepsy Care, University of Minnesota, Minneapolis, MN, USA; College of Pharmacy, University of Minnesota, Minneapolis, MN, USA
| | - Petr Marusic
- Department of Neurology, Charles University, 2nd Faculty of Medicine, Motol University Hospital, Prague, Czech Republic
| | - Stefano Meletti
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | | | - Chris J A Moulin
- Laboratory for the Study of Learning and Development, University of Bourgogne, Dijon, France
| | - Nils Muhlert
- School of Psychology and Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, Wales, UK
| | - Marco Mula
- Epilepsy Group, Atkinson Morley Regional Neuroscience Centre, St. George's Hospital, London, UK; Institute of Medical and Biomedical Sciences, St. George's University of London, London, UK
| | - Karl O Nakken
- National Centre for Epilepsy, Oslo University Hospital, Norway
| | - Fabienne Picard
- Department of Neurology, University Hospital and Medical School of Geneva, Switzerland
| | | | - William Theodore
- Clinical Epilepsy Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Peter Wolf
- Danish Epilepsy Centre Filadelfia, Dianalund, Denmark; Department of Clinical Medicine, Neurological Service, Federal University of Santa Catarina, Florianópolis, SC, Brazil
| | - Adam Zeman
- University of Exeter Medical School, St. Luke's Campus, Exeter, UK
| | - Ivan Rektor
- Masaryk University, Brno Epilepsy Center, St. Anne's Hospital and School of Medicine, Brno, Czech Republic; Central European Institute of Technology (CEITEC), Brno, Czech Republic
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478
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He L, Wang M, Zhang G, Qiu G, Cai D, Wu Z, Zhang X. Remediation of Cr(VI) contaminated soil using long-duration sodium thiosulfate supported by micro-nano networks. J Hazard Mater 2015; 294:64-69. [PMID: 25855614 DOI: 10.1016/j.jhazmat.2015.03.052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 03/05/2015] [Accepted: 03/24/2015] [Indexed: 06/04/2023]
Abstract
In this work, a long-duration remediation agent (LRA) on hexavalent chromium (Cr(VI)) was developed using sodium thiosulfate (ST) supported by attapulgite (ATP) micro-nano networks induced through high-energy electron beam (HEEB) irradiation. The ATP networks could effectively reduce the leaching amount of Cr(VI) in soil. More importantly, the ATP networks could significantly control the leaching behavior of ST, and then prolong the duration and increase the reduction efficiency of ST on Cr(VI). As a result, LRA displayed high performance on controlling the migration of Cr(VI) and reducing Cr(VI) to Cr(III). Additionally, pot experiment indicated that LRA could effectively decrease the absorbed amount of Cr(VI) in corn, and reduce the inhibition effect of Cr(VI) on the growth of corn. Therefore, this work could provide a facile approach to remediate the Cr(VI)-contaminated soil and lower the harmful effect of Cr(VI) on crop.
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Affiliation(s)
- Lulu He
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, People's Republic of China; Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031, People's Republic of China
| | - Min Wang
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031, People's Republic of China; Bioenergy Forest Research Center of State Forestry Administration, Hefei 230031, People's Republic of China
| | - Guilong Zhang
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031, People's Republic of China; Bioenergy Forest Research Center of State Forestry Administration, Hefei 230031, People's Republic of China
| | - Guannan Qiu
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031, People's Republic of China
| | - Dongqing Cai
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031, People's Republic of China; Bioenergy Forest Research Center of State Forestry Administration, Hefei 230031, People's Republic of China.
| | - Zhengyan Wu
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031, People's Republic of China; Bioenergy Forest Research Center of State Forestry Administration, Hefei 230031, People's Republic of China.
| | - Xin Zhang
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, People's Republic of China.
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479
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Adnan A, Barnett A, Moayedi M, McCormick C, Cohn M, McAndrews MP. Distinct hippocampal functional networks revealed by tractography-based parcellation. Brain Struct Funct 2015. [PMID: 26206251 DOI: 10.1007/s00429-015-1084-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent research suggests the anterior and posterior hippocampus form part of two distinct functional neural networks. Here we investigate the structural underpinnings of this functional connectivity difference using diffusion-weighted imaging-based parcellation. Using this technique, we substantiated that the hippocampus can be parcellated into distinct anterior and posterior segments. These structurally defined segments did indeed show different patterns of resting state functional connectivity, in that the anterior segment showed greater connectivity with temporal and orbitofrontal cortex, whereas the posterior segment was more highly connected to medial and lateral parietal cortex. Furthermore, we showed that the posterior hippocampal connectivity to memory processing regions, including the dorsolateral prefrontal cortex, parahippocampal, inferior temporal and fusiform gyri and the precuneus, predicted interindividual relational memory performance. These findings provide important support for the integration of structural and functional connectivity in understanding the brain networks underlying episodic memory.
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Affiliation(s)
- Areeba Adnan
- Department of Psychology, York University, Toronto, ON, M3J 1P3, Canada.
| | - Alexander Barnett
- Krembil Neuroscience Center and Toronto Western Research Institute, University Health Network, Toronto, ON, M5T 2S8, Canada.,Department of Psychology, University of Toronto, Toronto, ON, M5S 3G3, Canada
| | - Massieh Moayedi
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK
| | - Cornelia McCormick
- Krembil Neuroscience Center and Toronto Western Research Institute, University Health Network, Toronto, ON, M5T 2S8, Canada.,Centre for Developmental Cognitive Neuroscience, University College London, London, WC1E 3BG, UK
| | - Melanie Cohn
- Krembil Neuroscience Center and Toronto Western Research Institute, University Health Network, Toronto, ON, M5T 2S8, Canada.,Department of Psychology, University of Toronto, Toronto, ON, M5S 3G3, Canada
| | - Mary Pat McAndrews
- Krembil Neuroscience Center and Toronto Western Research Institute, University Health Network, Toronto, ON, M5T 2S8, Canada.,Department of Psychology, University of Toronto, Toronto, ON, M5S 3G3, Canada
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480
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Lehmann M, Madison C, Ghosh PM, Miller ZA, Greicius MD, Kramer JH, Coppola G, Miller BL, Jagust WJ, Gorno-Tempini ML, Seeley WW, Rabinovici GD. Loss of functional connectivity is greater outside the default mode network in nonfamilial early-onset Alzheimer's disease variants. Neurobiol Aging 2015; 36:2678-86. [PMID: 26242705 DOI: 10.1016/j.neurobiolaging.2015.06.029] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 06/16/2015] [Accepted: 06/18/2015] [Indexed: 12/21/2022]
Abstract
The common and specific involvement of brain networks in clinical variants of Alzheimer's disease (AD) is not well understood. We performed task-free ("resting-state") functional imaging in 60 nonfamilial AD patients, including 20 early-onset AD (age at onset <65 years, amnestic/dysexecutive deficits), 24 logopenic aphasia (language deficits), and 16 posterior cortical atrophy patients (visual deficits), as well as 60 healthy controls. Seed-based connectivity analyses were conducted to assess differences between groups in 3 default mode network (DMN) components (anterior, posterior, and ventral) and 4 additional non-DMN networks: left and right executive-control, language, and higher visual networks. Significant decreases in connectivity were found across AD variants compared with controls in the non-DMN networks. Within the DMN components, patients showed higher connectivity in the anterior DMN, in particular in logopenic aphasia. No significant differences were found for the posterior and ventral DMN. Our findings suggest that loss of functional connectivity is greatest in networks outside the DMN in early-onset and nonamnestic AD variants and may thus be a better biomarker in these patients.
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481
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Bothner MS, Kim YK, Lee W. Primary status, complementary status, and organizational survival in the U.S. venture capital industry. Soc Sci Res 2015; 52:588-601. [PMID: 26004482 DOI: 10.1016/j.ssresearch.2015.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 03/12/2015] [Accepted: 03/14/2015] [Indexed: 06/04/2023]
Abstract
We introduce a distinction between two kinds of status and examine their effects on the exit rates of organizations investing in the U.S. venture capital industry. Extending past work on status-based competition, we start with a simple baseline: we describe primary status as a network-related signal of an organization's quality in a leadership role, that is, as a function of the degree to which an organization leads others that are themselves well regarded as lead organizations in the context of investment syndicates. Combining Harary's (1959) image of the elite consultant with Goffman's (1956) concept of "capacity-esteem," we then discuss complementary status as an affiliation-based signal of an organization's quality in a supporting role. We measure complementary status as a function of the extent to which an organization is invited into syndicates by well-regarded lead organizations-that is, by those possessing high levels of primary status. Findings show that, conditioning on primary status, complementary status reduces the rate at which venture capital organizations exit the industry. Consistent with the premise that these kinds of status correspond to different roles and market identities, we also find that complementary status attenuates (and ultimately reverses) the otherwise favorable effect of primary status on an organization's life chances. Theoretically and methodologically oriented scope conditions, as well as implications for future research, are discussed.
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Affiliation(s)
- Matthew S Bothner
- ESMT European School of Management and Technology, Schlossplatz 1, 10178 Berlin, Germany.
| | - Young-Kyu Kim
- Korea University Business School, 145 Anam-ro, Seongbuk-gu, Seoul 136-701, Republic of Korea.
| | - Wonjae Lee
- Graduate School of Culture Technology, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea
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482
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Qi S, Meesters S, Nicolay K, Romeny BMTH, Ossenblok P. The influence of construction methodology on structural brain network measures: A review. J Neurosci Methods 2015; 253:170-82. [PMID: 26129743 DOI: 10.1016/j.jneumeth.2015.06.016] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 06/16/2015] [Accepted: 06/17/2015] [Indexed: 12/18/2022]
Abstract
Structural brain networks based on diffusion MRI and tractography show robust attributes such as small-worldness, hierarchical modularity, and rich-club organization. However, there are large discrepancies in the reports about specific network measures. It is hypothesized that these discrepancies result from the influence of construction methodology. We surveyed the methodological options and their influences on network measures. It is found that most network measures are sensitive to the scale of brain parcellation, MRI gradient schemes and orientation model, and the tractography algorithm, which is in accordance with the theoretical analysis of the small-world network model. Different network weighting schemes represent different attributes of brain networks, which makes these schemes incomparable between studies. Methodology choice depends on the specific study objectives and a clear understanding of the pros and cons of a particular methodology. Because there is no way to eliminate these influences, it seems more practical to quantify them, optimize the methodologies, and construct structural brain networks with multiple spatial resolutions, multiple edge densities, and multiple weighting schemes.
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Affiliation(s)
- Shouliang Qi
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China; Academic Center for Epileptology Kempenhaeghe & Maastricht UMC+, Heeze, The Netherlands; Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
| | - Stephan Meesters
- Department of Mathematics & Computer Science, Eindhoven University of Technology, Eindhoven, The Netherlands; Academic Center for Epileptology Kempenhaeghe & Maastricht UMC+, Heeze, The Netherlands
| | - Klaas Nicolay
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Bart M Ter Haar Romeny
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China; Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Pauly Ossenblok
- Academic Center for Epileptology Kempenhaeghe & Maastricht UMC+, Heeze, The Netherlands; Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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483
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Marcum CS, Koehly LM. Inter-generational contact from a network perspective. Adv Life Course Res 2015; 24:10-20. [PMID: 26047986 DOI: 10.1016/_j.alcr.2015.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 04/02/2015] [Accepted: 04/06/2015] [Indexed: 05/22/2023]
Abstract
Pathways for resource--or other--exchanges within families have long been known to be dependent on the structure of relations between generations (Agree et al., 2005; Fuller-Thomson et al., 1997; Silverstein, 2011; Treas & Marcum, 2011). Much life course research has theorized models of inter-generational exchange--including, the 'sandwich generation' (Miller, 1981) and the 'skipped generation' pathways (Chalfie, 1994)--but there is little work relating these theories to relevant network mechanisms such as liaison brokerage (Gould & Fernandez, 1989) and other triadic configurations (Davis & Leinhardt, 1972; Wasserman & Faust, 1994). To address this, a survey of models of resource allocation between members of inter-generational households from a network perspective is introduced in this paper. Exemplary data come from health discussion networks among Mexican-origin multi-generational households.
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484
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Marcum CS, Koehly LM. Inter-generational contact from a network perspective. Adv Life Course Res 2015; 24:10-20. [PMID: 26047986 PMCID: PMC4458302 DOI: 10.1016/j.alcr.2015.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 04/02/2015] [Accepted: 04/06/2015] [Indexed: 06/04/2023]
Abstract
Pathways for resource--or other--exchanges within families have long been known to be dependent on the structure of relations between generations (Agree et al., 2005; Fuller-Thomson et al., 1997; Silverstein, 2011; Treas & Marcum, 2011). Much life course research has theorized models of inter-generational exchange--including, the 'sandwich generation' (Miller, 1981) and the 'skipped generation' pathways (Chalfie, 1994)--but there is little work relating these theories to relevant network mechanisms such as liaison brokerage (Gould & Fernandez, 1989) and other triadic configurations (Davis & Leinhardt, 1972; Wasserman & Faust, 1994). To address this, a survey of models of resource allocation between members of inter-generational households from a network perspective is introduced in this paper. Exemplary data come from health discussion networks among Mexican-origin multi-generational households.
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485
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Rözer J, Mollenhorst G, Poortman AR. Family and Friends: Which Types of Personal Relationships Go Together in a Network? Soc Indic Res 2015; 127:809-826. [PMID: 27239093 PMCID: PMC4863920 DOI: 10.1007/s11205-015-0987-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/09/2015] [Indexed: 06/05/2023]
Abstract
We examine the link between family and personal networks. Using arguments about meeting opportunities, competition and social influence, we hypothesise how the presence of specific types of family members (i.e., a partner, children, parents and siblings) and non-family members (i.e., friends, neighbours and colleagues) in the network mutually affect one another. In addition, we propose that-beyond their mere presence-the active role of family members in the network strongly affects the presence of non-family members in the network. Data from the third wave of the Survey on the Social Networks of the Dutch, collected in 2012 and 2013, show that active involvement is of key importance; more than merely having family members present in one's personal network, the active involvement of specific types of family members in the personal network is associated with having disproportionally more other family members and having somewhat fewer non-family members in the network.
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Affiliation(s)
- Jesper Rözer
- />Department of Sociology/ICS, Utrecht University, Padualaan 14, 3584 CH Utrecht, The Netherlands
| | - Gerald Mollenhorst
- />Department of Human Geography and Spatial Planning, Utrecht University, Utrecht, The Netherlands
- />Department of Sociology, Stockholm University, Stockholm, Sweden
| | - Anne-Rigt Poortman
- />Department of Sociology/ICS, Utrecht University, Padualaan 14, 3584 CH Utrecht, The Netherlands
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486
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McMenamin BW, Pessoa L. Discovering networks altered by potential threat ("anxiety") using quadratic discriminant analysis. Neuroimage 2015; 116:1-9. [PMID: 25969398 DOI: 10.1016/j.neuroimage.2015.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 04/29/2015] [Accepted: 05/02/2015] [Indexed: 11/24/2022] Open
Abstract
Researchers have only recently begun using functional neuroimaging to explore the human response to periods of sustained anxious anticipation, namely potential threat. Here, we investigated brain responses acquired with functional MRI during an instructed threat of shock paradigm used to create sustained periods of aversive anticipation. In this re-analysis of previously published data, we employed quadratic discriminant analysis to classify the multivariate pattern of whole-brain functional connectivity and to identify connectivity changes during periods of potential threat. Our method identifies clusters with altered connectivity on a voxelwise basis, thus eschewing the need to define regions a priori. Classifier generalization was evaluated by testing on data from participants not used during training. Robust classification between threat and safe contexts was possible, and inspection of "diagnostic features" revealed altered functional connectivity involving the intraparietal sulcus, task-negative regions, striatum, and anterior cingulate cortex. We anticipate that the proposed method will prove useful to experimenters wishing to identify large-scale functional networks that distinguish between experimental conditions or groups.
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Affiliation(s)
| | - Luiz Pessoa
- Department of Psychology, University of Maryland, College Park, USA
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487
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Apostolopoulos Y, Sönmez S, Lemke MK, Rothenberg RB. Mapping U.S. long-haul truck drivers' multiplex networks and risk topography in inner-city neighborhoods. Health Place 2015; 34:9-18. [PMID: 25863181 DOI: 10.1016/j.healthplace.2015.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 03/09/2015] [Accepted: 03/13/2015] [Indexed: 10/23/2022]
Abstract
This article illustrates how urban inner-city trucking milieux may influence STI/BBI/HIV acquisition and transmission risks for U.S. long-haul truckers, as well as their social and risk relationships. Using mixed methods, we collected ethnoepidemiological and biological data from long-haul truck drivers and their risk contacts in inner-city trucking milieux in Atlanta, Georgia, United States. Key findings indicate that within the risk-endemic environment of distressed inner-city areas, diverse trucking risk milieux can amplify STI/BBI/HIV risk for multiplex networks of truckers. Inner-city neighborhood location, short geographic distance among risk contacts, and trucker concurrency can potentially exacerbate transmission via bridging higher-risk individuals with lower-risk populations at disparate geographic and epidemiological locations.
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Affiliation(s)
- Yorghos Apostolopoulos
- Texas A&M University, 4243 TAMU, College Station, TX 77843, USA; Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Sevil Sönmez
- University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | | | - Richard B Rothenberg
- Emory University School of Medicine, Atlanta, GA 30322, USA; Georgia State University, Atlanta, GA 30302, USA
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488
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Abstract
All brain normal or pathological activities occur in one of the states of vigilance: wake, slow-wave sleep, or REM sleep. Neocortical seizures preferentially occur during slow-wave sleep. We provide a description of neuronal behavior and mechanisms mediating such a behavior within neocortex taking place in natural states of vigilance as well as during seizures pointing to similarities and differences exhibited during sleep and seizures. A concept of epileptic focus is described using a model of cortical undercut, because in that model, the borders of the focus are well defined. In this model, as in other models of acquired epilepsy, the main factor altering excitability is deafferentation, which upregulates neuronal excitability that promotes generation of seizures. Periods of disfacilitation recorded during slow-wave sleep further upregulate neuronal excitability. It appears that the state of neurons and neuronal network in the epileptic focus produced by deafferentation are such that seizures cannot be generated there. Instead, seizures always start around the perimeter of the undercut cortex. Therefore, we define these areas as the seizure focus. In this zone, neuronal connectivity and excitability are moderately enhanced, lowering the threshold for seizure generation.
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489
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Aiello M, Salvatore E, Cachia A, Pappatà S, Cavaliere C, Prinster A, Nicolai E, Salvatore M, Baron JC, Quarantelli M. Relationship between simultaneously acquired resting-state regional cerebral glucose metabolism and functional MRI: a PET/MR hybrid scanner study. Neuroimage 2015; 113:111-21. [PMID: 25791784 DOI: 10.1016/j.neuroimage.2015.03.017] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 03/05/2015] [Accepted: 03/09/2015] [Indexed: 11/20/2022] Open
Abstract
Recently introduced hybrid PET/MR scanners provide the opportunity to measure simultaneously, and in direct spatial correspondence, both metabolic demand and functional activity of the brain, hence capturing complementary information on the brain's physiological state. Here we exploited PET/MR simultaneous imaging to explore the relationship between the metabolic information provided by resting-state fluorodeoxyglucose-PET (FDG-PET) and fMRI (rs-fMRI) in neurologically healthy subjects. Regional homogeneity (ReHo), fractional amplitude of low frequency fluctuations (fALFF), and degree of centrality (DC) maps were generated from the rs-fMRI data in 23 subjects, and voxel-wise comparison to glucose uptake distribution provided by simultaneously acquired FDG-PET was performed. The mutual relationships among each couple of these four metrics were explored in terms of similarity, both of spatial distribution across the brain and the whole group, and voxel-wise across subjects, taking into account partial volume effects by adjusting for grey matter (GM) volume. Although a significant correlation between the spatial distribution of glucose uptake and rs-fMRI derived metrics was present, only a limited percentage of GM voxels correlated with PET across subjects. Moreover, the correlation between the spatial distributions of PET and rs-fMRI-derived metrics is spatially heterogeneous across both anatomic regions and functional networks, with lowest correlation strength in the limbic network (Spearman rho around -0.11 for DC), and strongest correlation for the default-mode network (up to 0.89 for ReHo and 0.86 for fALFF). Overall, ReHo and fALFF provided significantly higher correlation coefficients with PET (p=10(-8) and 10(-7), respectively) as compared to DC, while no significant differences were present between ReHo and fALFF. Local GM volume variations introduced a limited overestimation of the rs-fMRI to FDG correlation between the modalities under investigation through partial volume effects. These novel results provide the basis for future studies of alterations of the coupling between brain metabolism and functional connectivity in pathologic conditions.
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490
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Rözer JJ, Mollenhorst G, Volker B. Romantic relationship formation, maintenance and changes in personal networks. Adv Life Course Res 2015; 23:86-97. [PMID: 26047843 DOI: 10.1016/j.alcr.2014.12.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 10/14/2014] [Accepted: 12/15/2014] [Indexed: 06/04/2023]
Abstract
According to the social withdrawal hypothesis, a personal network becomes smaller when a person starts dating, cohabitates and marries. This phenomenon is widely established in the literature. However, these studies were usually done with cross-sectional data. As a consequence, it is still unclear whether or how personal networks actually change after the formation of a romantic relationship (i.e. dating), after starting cohabitation and after getting married. It is also unclear how long and to what extent social withdrawal continues. To overcome these shortcomings, we examine how the size and composition of personal networks change after relationship formation. We use two waves of the PAIRFAM dataset (2008 and 2011), which include information about 6640 Germans who were between 16 and 39 years of age at the time of the second interview in 2008. Results from fixed effects regression models underscore that the association between romantic relationships and changes in personal networks is more dynamic than previous studies suggested. For example, after the formation of a romantic relationship people show a decrease in non-kin contacts, while an increase in non-kin contacts is observed after two years of dating, as well as after two years of cohabitation. These network changes suggest that people adapt their social networks to the demands and constraints of each phase of a romantic relationship. Because the decline in network size after dating is not stable, there is no need to be afraid that those who have a romantic partner remain isolated from other relationships.
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Affiliation(s)
| | - Gerald Mollenhorst
- Department of Human Geography and Spatial Planning, Utrecht University, The Netherlands; Department of Sociology, Stockholm University, Sweden
| | - Beate Volker
- Department of Sociology/ICS, Utrecht University, The Netherlands
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491
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Abstract
Infectious disease incidence data are increasingly available at the level of the individual and include high-resolution spatial components. Therefore, we are now better able to challenge models that explicitly represent space. Here, we consider five topics within spatial disease dynamics: the construction of network models; characterising threshold behaviour; modelling long-distance interactions; the appropriate scale for interventions; and the representation of population heterogeneity.
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Affiliation(s)
- Steven Riley
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, UK.
| | - Ken Eames
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Valerie Isham
- Department of Statistical Science, University College London, London, UK
| | - Denis Mollison
- Department of Actuarial Mathematics and Statistics, Heriot-Watt University, Edinburgh EH14 4AS, Scotland, UK
| | - Pieter Trapman
- Department of Mathematics, Stockholm University, Stockholm 106 91, Sweden
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492
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Ortman SG, Cabaniss AHF, Sturm JO, Bettencourt LMA. Settlement scaling and increasing returns in an ancient society. Sci Adv 2015; 1:e1400066. [PMID: 26601129 PMCID: PMC4644079 DOI: 10.1126/sciadv.1400066] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/01/2015] [Indexed: 05/16/2023]
Abstract
A key property of modern cities is increasing returns to scale-the finding that many socioeconomic outputs increase more rapidly than their population size. Recent theoretical work proposes that this phenomenon is the result of general network effects typical of human social networks embedded in space and, thus, is not necessarily limited to modern settlements. We examine the extent to which increasing returns are apparent in archaeological settlement data from the pre-Hispanic Basin of Mexico. We review previous work on the quantitative relationship between population size and average settled area in this society and then present a general analysis of their patterns of monument construction and house sizes. Estimated scaling parameter values and residual statistics support the hypothesis that increasing returns to scale characterized various forms of socioeconomic production available in the archaeological record and are found to be consistent with key expectations from settlement scaling theory. As a consequence, these results provide evidence that the essential processes that lead to increasing returns in contemporary cities may have characterized human settlements throughout history, and demonstrate that increasing returns do not require modern forms of political or economic organization.
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Affiliation(s)
- Scott G. Ortman
- Department of Anthropology, University of Colorado Boulder, Boulder, CO 80309–0233, USA
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
| | - Andrew H. F. Cabaniss
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
- Department of Classics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jennie O. Sturm
- Department of Anthropology, University of New Mexico, Albuquerque, NM 87131, USA
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493
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Abstract
We describe a novel version of MitoGraph, our fully automated image processing method and software, dedicated to calculating the volume of 3D intracellular structures and organelles in live cells. MitoGraph is optimized and validated for quantifying the volume of tubular mitochondrial networks in budding yeast. We therefore include the experimental protocol, microscopy conditions, and software parameters focusing on mitochondria in budding yeast. However, MitoGraph can also be applied to mitochondria in other cell types and possibly other intracellular structures. We begin with our protocol and then include substantial discussion of the validation, requirements, and limits of MitoGraph to aid a wide range of potential users in applying MitoGraph to their data and troubleshooting any potential problems that arise. MitoGraph is freely available at the Web site http://rafelski.com/susanne/MitoGraph.
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Affiliation(s)
- Matheus Palhares Viana
- Departments of Developmental and Cell Biology, University of California, Irvine, CA, USA
| | - Swee Lim
- Biomedical Engineering, University of California, Irvine, CA, USA
| | - Susanne M Rafelski
- Departments of Developmental and Cell Biology, University of California, Irvine, CA, USA; Biomedical Engineering, University of California, Irvine, CA, USA; Center for Complex Biological Systems, University of California, Irvine, CA, USA
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494
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Laatsch K. International atherosclerosis research school (iARS) 2014 in Hamburg, Germany. Atherosclerosis 2015; 238:407-8. [PMID: 25558035 DOI: 10.1016/j.atherosclerosis.2014.12.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 12/22/2014] [Indexed: 10/24/2022]
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495
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McDonald S. Network effects across the earnings distribution: payoffs to visible and invisible job finding assistance. Soc Sci Res 2015; 49:299-313. [PMID: 25432620 DOI: 10.1016/j.ssresearch.2014.08.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 07/14/2014] [Accepted: 08/20/2014] [Indexed: 06/04/2023]
Abstract
This study makes three critical contributions to the "Do Contacts Matter?" debate. First, the widely reported null relationship between informal job searching and wages is shown to be mostly the artifact of a coding error and sample selection restrictions. Second, previous analyses examined only active informal job searching without fully considering the benefits derived from unsolicited network assistance (the "invisible hand of social capital") - thereby underestimating the network effect. Third, wage returns to networks are examined across the earnings distribution. Longitudinal data from the NLSY reveal significant wage returns for network-based job finding over formal job searching, especially for individuals who were informally recruited into their jobs (non-searchers). Fixed effects quantile regression analyses show that contacts generate wage premiums among middle and high wage jobs, but not low wage jobs. These findings challenge conventional wisdom on contact effects and advance understanding of how social networks affect wage attainment and inequality.
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Affiliation(s)
- Steve McDonald
- North Carolina State University, Campus Box 8107, Raleigh, NC 27695-8107, United States.
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496
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Gough EK, Stephens DA, Moodie EE, Prendergast AJ, Stoltzfus RJ, Humphrey JH, Manges AR. Linear growth faltering in infants is associated with Acidaminococcus sp. and community-level changes in the gut microbiota. Microbiome 2015; 3:24. [PMID: 26106478 PMCID: PMC4477476 DOI: 10.1186/s40168-015-0089-2] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 06/04/2015] [Indexed: 05/20/2023]
Abstract
BACKGROUND Chronic malnutrition, termed stunting, is defined as suboptimal linear growth, affects one third of children in developing countries, and leads to increased mortality and poor developmental outcomes. The causes of childhood stunting are unknown, and strategies to improve growth and related outcomes in children have only had modest impacts. Recent studies have shown that the ecosystem of microbes in the human gut, termed the microbiota, can induce changes in weight. However, the specific changes in the gut microbiota that contribute to growth remain unknown, and no studies have investigated the gut microbiota as a determinant of chronic malnutrition. RESULTS We performed secondary analyses of data from two well-characterized twin cohorts of children from Malawi and Bangladesh to identify bacterial genera associated with linear growth. In a case-control analysis, we used the graphical lasso to estimate covariance network models of gut microbial interactions from relative genus abundances and used network analysis methods to select genera associated with stunting severity. In longitudinal analyses, we determined associations between these selected microbes and linear growth using between-within twin regression models to adjust for confounding and introduce temporality. Reduced microbiota diversity and increased covariance network density were associated with stunting severity, while increased relative abundance of Acidaminococcus sp. was associated with future linear growth deficits. CONCLUSIONS We show that length growth in children is associated with community-wide changes in the gut microbiota and with the abundance of the bacterial genus, Acidaminococcus. Larger cohorts are needed to confirm these findings and to clarify the mechanisms involved.
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Affiliation(s)
- Ethan K. Gough
- />Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, H3A 1A2, QC Canada
| | - David A. Stephens
- />Department of Mathematics and Statistics, McGill University, Montreal, H3A 2K6, QC Canada
| | - Erica E.M. Moodie
- />Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, H3A 1A2, QC Canada
| | - Andrew J. Prendergast
- />Centre for Paediatrics, Blizard Institute, Queen Mary University of London, London, E1 2AT UK
- />Zvitambo Institute for Maternal Child Health Research, Harare, Zimbabwe
| | - Rebecca J. Stoltzfus
- />Program in International Nutrition, Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853 USA
| | - Jean H. Humphrey
- />Zvitambo Institute for Maternal Child Health Research, Harare, Zimbabwe
- />Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205 USA
| | - Amee R. Manges
- />Faculty of Medicine, School of Population and Public Health, University of British Columbia, 137-2206 East Mall, Vancouver, V6T 1Z3, BC Canada
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497
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Letki N, Mieriņa I. Getting support in polarized societies: income, social networks, and socioeconomic context. Soc Sci Res 2015; 49:217-233. [PMID: 25432615 DOI: 10.1016/j.ssresearch.2014.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 07/22/2014] [Accepted: 08/05/2014] [Indexed: 06/04/2023]
Abstract
This paper explores how unequal resources and social and economic polarization affects the size of social networks and their use to access resources. We argue that individual resource position generates divergent expectations with regard to the impact of polarization on the size of networks on one hand, and their usefulness for accessing resources on the other. Social and economic polarization encourages reliance on informal networks, but those at the bottom of the social structure are forced to rely on more extensive networks than the wealthy to compensate for their isolated and underprivileged position. At the same time, social and economic polarization limits the resources the poor can access through their networks. We provide evidence consistent with these propositions, based on data derived from the International Social Survey Programme 2001 "Social Networks" dataset combined with contextual information on the levels of economic inequality in particular countries along with whether they experienced postcommunism.
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Affiliation(s)
- Natalia Letki
- Institute of Sociology, University of Warsaw, ul. Karowa 18, 00-927 Warsaw, Poland.
| | - Inta Mieriņa
- Institute of Philosophy and Sociology, University of Latvia, Latvia
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498
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Abstract
The par-titioning-defective or PAR proteins comprise the core of an essential cell polarity network that underlies polarization in a wide variety of cell types and developmental contexts. The output of this network in nearly every case is the establishment of opposing and complementary membrane domains that define a cell׳s polarity axis. Yet, behind this simple pattern is a complex system of interactions, regulation and dynamic behaviors. How these various parts combine to generate polarized patterns of protein localization in cells is only beginning to become clear. This review, part of the Special Issue on Cell Polarity, aims to highlight several emerging themes and design principles that underlie the process of cell polarization by components of the PAR network.
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Affiliation(s)
- Nathan W Goehring
- Cancer Research UK London Research Institute, 44 Lincoln׳s Inn Fields, London WC2A 3LY, UK; MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
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499
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Jamieson DG, Moss A, Kennedy M, Jones S, Nenadic G, Robertson DL, Sidders B. The pain interactome: connecting pain-specific protein interactions. Pain 2014; 155:2243-52. [PMID: 24978826 PMCID: PMC4247380 DOI: 10.1016/j.pain.2014.06.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 06/13/2014] [Accepted: 06/23/2014] [Indexed: 11/29/2022]
Abstract
Understanding the molecular mechanisms associated with disease is a central goal of modern medical research. As such, many thousands of experiments have been published that detail individual molecular events that contribute to a disease. Here we use a semi-automated text mining approach to accurately and exhaustively curate the primary literature for chronic pain states. In so doing, we create a comprehensive network of 1,002 contextualized protein-protein interactions (PPIs) specifically associated with pain. The PPIs form a highly interconnected and coherent structure, and the resulting network provides an alternative to those derived from connecting genes associated with pain using interactions that have not been shown to occur in a painful state. We exploit the contextual data associated with our interactions to analyse subnetworks specific to inflammatory and neuropathic pain, and to various anatomical regions. Here, we identify potential targets for further study and several drug-repurposing opportunities. Finally, the network provides a framework for the interpretation of new data within the field of pain.
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Affiliation(s)
- Daniel G Jamieson
- Computational and Evolutionary Biology, Faculty of Life Sciences, University of Manchester, Manchester, UK; Computer Science, Faculty of Engineering and Physical Sciences, University of Manchester, Manchester, UK
| | - Andrew Moss
- Neusentis, Pfizer, Worldwide Research & Development, Cambridge, UK
| | - Michael Kennedy
- Neusentis, Pfizer, Worldwide Research & Development, Cambridge, UK
| | - Sherrie Jones
- Cancer Research UK Manchester Institute, University of Manchester, Manchester, UK
| | - Goran Nenadic
- Computer Science, Faculty of Engineering and Physical Sciences, University of Manchester, Manchester, UK; Manchester Institute of Biotechnology, University of Manchester, Manchester, UK
| | - David L Robertson
- Computational and Evolutionary Biology, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Ben Sidders
- Neusentis, Pfizer, Worldwide Research & Development, Cambridge, UK.
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500
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Fitjar RD, Gjelsvik M, Rodríguez-Pose A. Organizing product innovation: hierarchy, market or triple-helix networks? Triple Helix (Heidelb) 2014; 1:3. [PMID: 27069846 PMCID: PMC4804719 DOI: 10.1186/s40604-014-0003-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 06/18/2014] [Indexed: 06/05/2023]
Abstract
This paper assesses the extent to which the organization of the innovation effort in firms, as well as the geographical scale at which this effort is pursued, affects the capacity to benefit from product innovations. Three alternative modes of organization are studied: hierarchy, market and triple-helix-type networks. Furthermore, we consider triple-helix networks at three geographical scales: local, national and international. These relationships are tested on a random sample of 763 firms located in five urban regions of Norway which reported having introduced new products or services during the preceding 3 years. The analysis shows that firms exploiting internal hierarchy or triple-helix networks with a wide range of partners managed to derive a significantly higher share of their income from new products, compared to those that mainly relied on outsourcing within the market. In addition, the analysis shows that the geographical scale of cooperation in networks, as well as the type of partner used, matters for the capacity of firms to benefit from product innovation. In particular, firms that collaborate in international triple-helix-type networks involving suppliers, customers and R&D institutions extract a higher share of their income from product innovations, regardless of whether they organize the processes internally or through the network.
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Affiliation(s)
- Rune Dahl Fitjar
- />UiS Business School, University of Stavanger, Stavanger, 4036 Norway
| | - Martin Gjelsvik
- />Stavanger Centre for Innovation Research, International Research Institute of Stavanger, PO Box 8046, N-4068 Stavanger, Norway
| | - Andrés Rodríguez-Pose
- />London School of Economics and Political Science, Houghton Street, London, WC2A 2AE United Kingdom
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