Stable fixed points of combinatorial threshold-linear networks

Combinatorial threshold-linear networks (CTLNs) are a special class of recurrent neural networks whose dynamics are tightly controlled by an underlying directed graph. Recurrent networks have long been used as models for associative memory and pattern completion, with stable fixed points playing the role of stored memory patterns in the network. In prior work, we showed that target-free cliques of the graph correspond to stable fixed points of the dynamics, and we conjectured that these are the only stable fixed points possible [1, 2]. In this paper, we prove that the conjecture holds in a variety of special cases, including for networks with very strong inhibition and graphs of size n ≤ 4 . We also provide further evi-dence for the conjecture by showing that sparse graphs and graphs that are nearly cliques can never support stable fixed points. Finally, we translate some results from extremal com-binatorics to obtain an upper bound on the number of stable fixed points of CTLNs in cases where the conjecture holds.

"We're not broken. We're human." A qualitative meta-synthesis of health-care providers' experiences participating in well-being programs

INTRODUCTION

Protecting health-care provider (HCP) well-being is imperative to preserve health-care workforce capital, performance, and patient care quality. Limited evidence exists for the long-term effectiveness of HCP well-being programs, with less known about physiotherapists specifically.

PURPOSE

To review and synthesize qualitative research describing experiences of HCP, generate lessons learned from the greater population of HCP participating in workplace well-being programs, and then to inform programs and policies for optimizing psychological well-being in an understudied population of physiotherapists.

METHODS

This qualitative meta-synthesis included a systematic literature search conducted in September 2020; critical appraisal of results; and data reduction, re-categorizing, and thematic extraction (reciprocal translation) with interpretive triangulation.

RESULTS

Twenty-five papers met the inclusion criteria. Participants included physicians, nurses, and allied health providers. All programs targeted the individual provider and included psychoeducational offerings, supervision groups, coaching, and complementary therapies. Four themes were constructed: 1) beneficial outcomes across a range of programs; 2) facilitators of program success; 3) barriers to program success; and 4) unmet needs driving recommendations.

CONCLUSIONS

The findings enhance our understanding of diverse individual-level programs to address HCP well-being. Beneficial outcomes were achieved across program types with system-level support proving critical; however, HCP described barriers to program success (HCP characteristics, off-site programs, institutional culture) and remaining needs (resources, ethical dissonance) left unaddressed. Organizations should offer individual-level programs to support physiotherapists in the short term while pursuing long-term, system-level change to address drivers of well-being.

Presumptive phenobarbital-induced systemic lupus erythematosus in a domestic dog

CASE DESCRIPTION

We describe a case of presumptive acquired systemic lupus erythematosus secondary to phenobarbital administration in a dog, which resolved with withdrawal of the drug.

CLINICAL FINDINGS

A 3.5 year-old poodle presented to a veterinary teaching hospital for Tier 1 idiopathic epilepsy and was treated with phenobarbital. The dog experienced fever, multiple cytopenias, and proteinuria in conjunction with a positive antinuclear antibody (ANA) titer.

DIAGNOSTICS

Serial CBCs, urine protein : creatinine ratios, and sternal bone marrow aspirates were performed to evaluate improvement.

TREATMENT AND OUTCOME

Phenobarbital was withdrawn and levetiracetam initiated. All abnormalities resolved with supportive care, without initiation of immunosuppressive drugs. All cytopenias and proteinuria resolved and ANA test results became negative within 3 months. The patient recovered and did well clinically.

CLINICAL RELEVANCE

Systemic lupus erythematosus is a disease of multiple autoimmune syndromes occurring concurrently or sequentially in conjunction with the presence of circulating ANA. It has been well described in dogs as an idiopathic condition, but in human medicine may occur secondary to drug reactions (drug-associated lupus) including as a reaction to phenobarbital. The findings in our case are consistent with the criteria for drug-induced lupus in humans and we suggest it as the first report of phenobarbital-induced lupus in a dog.

Superiority of BNCT Treatment Planning Metrics Achieved Using Novel vs. Reference (BPA-F) Pharmaceuticals in Head and Neck Locations

PURPOSE/OBJECTIVE(S)

Several novel boron delivery compounds currently under investigation by our group have demonstrated formulation, biodistribution, and dose response benefits in small animal models [1]. In this study we analyze the potential clinical impact of these compounds for boron neutron capture therapy (BNCT) in human patients.

MATERIALS/METHODS

Pharmacokinetic models were used to estimate the tumor and normal tissue boron concentrations after continuous infusion of the novel compounds and BPA-F. Patient model segmentation, material assignment, and alignment of one or more treatment beams were exported from a commercial treatment planning system (TPS) to a novel dose calculation tool. This information was used to generate a voxelized model that incorporated the source, beam shaping assembly, collimator, and patient materials so that the full albedo effect was included in each dose calculation. Physical dose from 10B(n,α), 14N(n,p), 1H(n,n') interactions plus gamma rays from 1H(n,γ) and other reactions within the patient and treatment equipment were calculated by Monte Carlo transport of particles originating in a pre-generated phase space at the cover surface. RBE and CBE weighting factors are applied to combine these four physical dose volumes into an equivalent dose volume, and these five dose volumes were passed back to the TPS for evaluation.

RESULTS

Tumor dose was increased by up to 2.6x for the novel compounds while normal tissue doses were constant or slightly reduced in comparison to BPA-F plans. Alternatively, for identical tumor dose the normal tissue doses and treatment time were reduced by up to 2.6x. In addition, in some cases it was possible to generate a single beam treatment plan using the new compounds that delivered higher tumor dose and lower normal tissues doses than a multiple beam plan using BPA-F.

CONCLUSION

This study demonstrates both dosimetric and practical benefits of the new compounds in comparison to BPA-F, including the potential to deliver treatment using fewer beam directions and correspondingly easier treatment setups and higher patient throughput. The potential of these compounds to extend the range of clinical indications for BNCT is also discussed. These results motivate upcoming experimental testing of the key assumptions involved in their calculation.

Surrogate Adiposity Markers and Mortality

Importance

Body mass index (BMI) is an easily obtained adiposity surrogate. However, there is variability in body composition and adipose tissue distribution between individuals with the same BMI, and there is controversy regarding the BMI associated with the lowest mortality risk.

Objective

To evaluate which of BMI, fat mass index (FMI), and waist-to-hip (WHR) has the strongest and most consistent association with mortality.

Design, Setting, and Participant

This cohort study used incident deaths from the UK Biobank (UKB; 2006-2022), which includes data from 22 clinical assessment centers across the United Kingdom. UKB British participants of British White ancestry (N = 387 672) were partitioned into a discovery cohort (n = 337 078) and validation cohort (n = 50 594), with the latter consisting of 25 297 deaths and 25 297 controls. The discovery cohort was used to derive genetically determined adiposity measures while the validation cohort was used for analyses. Exposure-outcome associations were analyzed through observational and mendelian randomization (MR) analyses.

Exposures

BMI, FMI, and WHR.

Main Outcomes and Measures

All-cause and cause-specific (cancer, cardiovascular disease [CVD], respiratory disease, or other causes) mortality.

Results

There were 387 672 and 50 594 participants in our observational (mean [SD] age, 56.9 [8.0] years; 177 340 [45.9%] male, 210 332 [54.2%], female), and MR (mean [SD] age, 61.6 [6.2] years; 30 031 [59.3%] male, 20 563 [40.6%], female) analyses, respectively. Associations between measured BMI and FMI with all-cause mortality were J-shaped, whereas the association of WHR with all-cause mortality was linear using the hazard ratio (HR) scale (HR per SD increase of WHR, 1.41 [95% CI, 1.38-1.43]). Genetically determined WHR had a stronger association with all-cause mortality than BMI (odds ratio [OR] per SD increase of WHR, 1.51 [95% CI, 1.32-1.72]; OR per SD increase of BMI, 1.29 [95% CI, 1.20-1.38]; P for heterogeneity = .02). This association was stronger in male than female participants (OR, 1.89 [95% CI, 1.54-2.32]; P for heterogeneity = .01). Unlike BMI or FMI, the genetically determined WHR-all-cause mortality association was consistent irrespective of observed BMI.

Conclusions and Relevance

In this cohort study, WHR had the strongest and most consistent association with mortality irrespective of BMI. Clinical recommendations should consider focusing on adiposity distribution compared with mass.

Severe obesity and global developmental delay in preschool children: Findings from a Canadian Paediatric Surveillance Program study

Background

The co-presentation of severe obesity (SO) and global developmental delay (GDD) in Canadian preschool children has not been examined. However, SO and GDD may require syndromic diagnoses and unique management considerations.

Objectives

To determine (1) minimum incidence; (2) age of onset and risk factors; and (3) health care utilization for co-presenting SO and GDD.

Methods

Through the Canadian Paediatric Surveillance Program (CPSP), a monthly form was distributed to participants from February 2018 to January 2020 asking for reports of new cases of SO and GDD among children ≤5 years of age. We performed descriptive statistics for quantitative questions and qualitative content analysis for open-ended questions.

Results

Forty-seven cases (64% male; 51% white; mean age: 3.5 ± 1.2 years) were included. Age of first weight concern was 2.5 ± 1.3 years and age of GDD diagnosis was 2.7 ± 1.4 years. Minimum incidence of SO and GDD was 3.3 cases per 100,000 for ≤5 years of age per year. Identified problems included school and/or behavioural problems (n = 17; 36%), snoring (n = 14; 30%), and asthma/recurrent wheeze (n = 10; 21%). Mothers of 32% of cases (n = 15) had obesity and 21% of cases (n = 10) received neonatal intensive care. Microarray was ordered for 57% (n = 27) of children. A variety of clinicians and services were accessed. As reported by CPSP participants, challenges faced by families and health service access were barriers to care.

Conclusion

Children with SO and GDD have multiple comorbidities, and require early identification and referral to appropriate services. These cases may also benefit from additional testing to rule out known genetic obesity syndromes.

Cyclic hematopoiesis in a mixed-breed dog: case report and brief review

An 8-wk-old, male, mixed-breed puppy was adopted from a rescue organization. From the time of adoption, the puppy suffered episodes of illness affecting various organ systems, which resolved with supportive therapy but relapsed once medical therapy was discontinued. Review of the hematologic data revealed cyclic fluctuations in circulating blood cells. Cyclicity was most prominent in neutrophils, with recurrent severe neutropenia. Neutropenic episodes lasted 5-6 d, with regular cycles of 11-14 d between nadir neutrophil counts. Genetic testing determined that the patient was homozygous mutant for the frameshift mutation in the adaptor protein complex 3 β-subunit (AP3B1) gene, originally identified in gray collies with cyclic hematopoiesis (CH). Pedigree information was not available, but the patient's features were phenotypically distinct from those of collies. We describe here a case of the AP3B1 mutation in a mixed-breed dog that did not resemble a collie, undescribed previously, to our knowledge. Our findings indicate that the AP3B1 mutation and CH are present within the general canine population and are not restricted to collies.

Maternal Schizophrenia and the Risk of a Childhood Chronic Condition

BACKGROUND AND HYPOTHESIS

Maternal schizophrenia heightens the risk for certain perinatal complications, yet it is not known to what degree future childhood chronic health conditions (Childhood-CC) might arise.

STUDY DESIGN

This population-based cohort study using health administrative data from Ontario, Canada (1995-2018) compared 5066 children of mothers with schizophrenia to 25 324 children of mothers without schizophrenia, propensity-matched on birth-year, maternal age, parity, immigrant status, income, region of residence, and maternal medical and psychiatric conditions other than schizophrenia. Cox proportional hazard models generated hazard ratios (HR) and 95% confidence intervals (CI) for incident Childhood-CCs, and all-cause mortality, up to age 19 years.

STUDY RESULTS

Six hundred and fifty-six children exposed to maternal schizophrenia developed a Childhood-CC (20.5/1000 person-years) vs. 2872 unexposed children (17.1/1000 person-years)-an HR of 1.18, 95% CI 1.08-1.28. Corresponding rates were 3.3 vs. 1.9/1000 person-years (1.77, 1.44-2.18) for mental health Childhood-CC, and 18.0 vs. 15.7/1000 person-years (1.13, 1.04-1.24) for non-mental health Childhood-CC. All-cause mortality rates were 1.2 vs. 0.8/1000 person-years (1.34, 0.96-1.89). Risk for children exposed to maternal schizophrenia was similar whether or not children were discharged to social service care. From age 1 year, risk was greater for children whose mothers were diagnosed with schizophrenia prior to pregnancy than for children whose mothers were diagnosed with schizophrenia postnatally.

CONCLUSIONS

A child exposed to maternal schizophrenia is at elevated risk of chronic health conditions including mental and physical subtypes. Future research should examine what explains the increased risk particularly for physical health conditions, and what preventive and treatment efforts are needed for these children.

Burnout and the role of authentic leadership in academic medicine

Background

Recently, there has been increasing evidence that reducing burnout in healthcare providers requires significant organizational efforts that include the integration of leadership strategies.

Methods

Focus groups were conducted across four health systems within the University of Colorado Department of Medicine in four affinity groups (administrative staff, medical trainees, research faculty, and clinical faculty). Authentic leadership theory was used for analysis to advance the understanding of the role of leadership style upon participants’ work experiences and preferences, and to identify opportunities for translation of site-specific results to other academic medical settings.

Results

Study participants from each affinity group believed their clinical leaders lacked objectivity with decision-making (lacking “balancing processing”), which contributed to their overall feeling of powerlessness. The experience of increasing work demands was salient throughout all twelve focus groups, and participants identified leadership that interacted in a more open and self-disclosing manner (“relational transparency”) as alleviating at least some of this burden. Strong preference discernable alignment between their leaders’ decision-making and their internal moral compass of values (demonstrating “internalized moral perspective”) was described, as was clinical leaders demonstrating “self-awareness” (having a self-reflective process that informs the leader’s decision-making). Comparing affinity group experiences within each authentic leadership theory construct identified the relevance of contextual factors, such as work setting and roles, upon employees’ perceptions and expectations of their leaders.

Conclusions

Use of authentic leadership theory advanced the understanding of the association between leadership traits and experiences of burnout amongst a large group of academic clinicians, researchers, trainees, and administrative staff. Leadership styles that promoted relationship transparency, openness, and support were preferred and fostering these traits may help address the demands in academic medicine, including symptoms of burnout.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-022-08034-x.

Efficacy of the Aim2Be intervention in changing lifestyle behaviours among adolescents with overweight and obesity: A Randomized Controlled Trial (Preprint)

BACKGROUND

Aim2Be is a gamified lifestyle app designed to promote lifestyle behavior changes among Canadian adolescents and their families.

OBJECTIVE

The primary aim was to test the efficacy of the Aim2Be app with support from a live coach to reduce weight outcomes (BMI Z score [zBMI]) and improve lifestyle behaviors among adolescents with overweight and obesity and their parents versus a waitlist control group over 3 months. The secondary aim was to compare health trajectories among waitlist control participants over 6 months (before and after receiving access to the app), assess whether support from a live coach enhanced intervention impact, and evaluate whether the app use influenced changes among intervention participants.

METHODS

A 2-arm parallel randomized controlled trial was conducted from November 2018 to June 2020. Adolescents aged 10 to 17 years with overweight or obesity and their parents were randomized into an intervention group (Aim2Be with a live coach for 6 months) or a waitlist control group (Aim2Be with no live coach; accessed after 3 months). Adolescents' assessments at baseline and at 3 and 6 months included measured height and weight, 24-hour dietary recalls, and daily step counts measured with a Fitbit. Data on self-reported physical activity, screen time, fruit and vegetable intake, and sugary beverage intake of adolescents and parents were also collected.

RESULTS

A total of 214 parent-child participants were randomized. In our primary analyses, there were no significant differences in zBMI or any of the health behaviors between the intervention and control groups at 3 months. In our secondary analyses, among waitlist control participants, zBMI (P=.02), discretionary calories (P=.03), and physical activity outside of school (P=.001) declined, whereas daily screen time increased (P<.001) after receiving access to the app compared with before receiving app access. Adolescents randomized to Aim2Be with live coaching reported more time being active outside of school compared with adolescents who used Aim2Be with no coaching over 3 months (P=.001). App use did not modify any changes in outcomes among adolescents in the intervention group.

CONCLUSIONS

The Aim2Be intervention did not improve zBMI and lifestyle behaviors in adolescents with overweight and obesity compared with the waitlist control group over 3 months. Future studies should explore the potential mediators of changes in zBMI and lifestyle behaviors as well as predictors of engagement.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03651284; https://clinicaltrials.gov/ct2/show/study/NCT03651284.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.1186/s13063-020-4080-2.

Serum metabolomic signatures of gestational diabetes in South Asian and white European women

INTRODUCTION

This study aimed to identify serum metabolomic signatures associated with gestational diabetes mellitus (GDM), and to examine if ethnic-specific differences exist between South Asian and white European women.

RESEARCH DESIGN AND METHODS

Prospective cohort study with a nested case-control analysis of 600 pregnant women from two Canadian birth cohorts; using an untargeted approach, 63 fasting serum metabolites were measured and analyzed using multisegment injection-capillary electrophoresis-mass spectrometry. Multivariate logistic regression modeling was conducted overall and by cohort.

RESULTS

The proportion of women with GDM was higher in South Asians (27.1%) compared with white Europeans (17.9%). Several amino acid, carbohydrate, and lipid pathways related to GDM were common to South Asian and white European women. Elevated circulating concentrations of glutamic acid, propionylcarnitine, tryptophan, arginine, 2-hydroxybutyric acid, 3-hydroxybutyric acid, and 3-methyl-2-oxovaleric acid were associated with higher odds of GDM, while higher glutamine, ornithine, oxoproline, cystine, glycine with lower odds of GDM. Per SD increase in glucose concentration, the odds of GDM increased (OR=2.07, 95% CI 1.58 to 2.71), similarly for metabolite ratios: glucose to glutamine (OR=2.15, 95% CI 1.65 to 2.80), glucose to creatinine (OR=1.79, 95% CI 1.39 to 2.32), and glutamic acid to glutamine (OR=1.46, 95% CI 1.16 to 1.83). South Asians had higher circulating ratios of glucose to glutamine, glucose to creatinine, arginine to ornithine, and citrulline to ornithine, compared with white Europeans.

CONCLUSIONS

We identified a panel of serum metabolites implicated in GDM pathophysiology, consistent in South Asian and white European women. The metabolic alterations leading to larger ratios of glucose to glutamine, glucose to creatinine, arginine to ornithine, and citrulline to ornithine in South Asians likely reflect the greater burden of GDM among South Asians compared with white Europeans.

DNA methylation changes in cord blood and the developmental origins of health and disease – a systematic review and replication study

Background

Environmental exposures in utero which modify DNA methylation may have a long-lasting impact on health and disease in offspring. We aimed to identify and replicate previously published genomic loci where DNA methylation changes are attributable to in utero exposures in the NutriGen birth cohort studies Alliance.

Methods

We reviewed the literature to identify differentially methylated sites of newborn DNA which are associated with the following five traits of interest maternal diabetes, pre-pregnancy body mass index (BMI), diet during pregnancy, smoking, and gestational age. We then attempted to replicate these published associations in the Canadian Healthy Infant Longitudinal Development (CHILD) and the South Asian birth cohort (START) cord blood epigenome-wide data.

Results

We screened 68 full-text articles and identified a total of 17 cord blood epigenome-wide association studies (EWAS) of the traits of interest. Out of the 290 CpG sites reported, 19 were identified in more than one study; all of them associated with maternal smoking. In CHILD and START EWAS, thousands of sites associated with gestational age were identified and maintained significance after correction for multiple testing. In CHILD, there was differential methylation observed for 8 of the published maternal smoking sites. No other traits tested (i.e., folate levels, gestational diabetes, birthweight) replicated in the CHILD or START cohorts.

Conclusions

Maternal smoking during pregnancy and gestational age are strongly associated with differential methylation in offspring cord blood, as assessed in the EWAS literature and our birth cohorts. There are a limited number of reported methylation sites associated in more than two independent studies related to pregnancy. Additional large studies of diverse populations with fine phenotyping are needed to produce robust epigenome-wide data in order to further elucidate the effect of intrauterine exposures on the infants’ methylome.

Core motifs predict dynamic attractors in combinatorial threshold-linear networks

Combinatorial threshold-linear networks (CTLNs) are a special class of inhibition-dominated TLNs defined from directed graphs. Like more general TLNs, they display a wide variety of nonlinear dynamics including multistability, limit cycles, quasiperiodic attractors, and chaos. In prior work, we have developed a detailed mathematical theory relating stable and unstable fixed points of CTLNs to graph-theoretic properties of the underlying network. Here we find that a special type of fixed points, corresponding to core motifs, are predictive of both static and dynamic attractors. Moreover, the attractors can be found by choosing initial conditions that are small perturbations of these fixed points. This motivates us to hypothesize that dynamic attractors of a network correspond to unstable fixed points supported on core motifs. We tested this hypothesis on a large family of directed graphs of size n = 5, and found remarkable agreement. Furthermore, we discovered that core motifs with similar embeddings give rise to nearly identical attractors. This allowed us to classify attractors based on structurally-defined graph families. Our results suggest that graphical properties of the connectivity can be used to predict a network's complex repertoire of nonlinear dynamics.

Sequential Attractors in Combinatorial Threshold-Linear Networks

Sequences of neural activity arise in many brain areas, including cortex, hippocampus, and central pattern generator circuits that underlie rhythmic behaviors like locomotion. While network architectures supporting sequence generation vary considerably, a common feature is an abundance of inhibition. In this work, we focus on architectures that support sequential activity in recurrently connected networks with inhibition-dominated dynamics. Specifically, we study emergent sequences in a special family of threshold-linear networks, called combinatorial threshold-linear networks (CTLNs), whose connectivity matrices are defined from directed graphs. Such networks naturally give rise to an abundance of sequences whose dynamics are tightly connected to the underlying graph. We find that architectures based on generalizations of cycle graphs produce limit cycle attractors that can be activated to generate transient or persistent (repeating) sequences. Each architecture type gives rise to an infinite family of graphs that can be built from arbitrary component subgraphs. Moreover, we prove a number of graph rules for the corresponding CTLNs in each family. The graph rules allow us to strongly constrain, and in some cases fully determine, the fixed points of the network in terms of the fixed points of the component subnetworks. Finally, we also show how the structure of certain architectures gives insight into the sequential dynamics of the corresponding attractor.

Common Core Assessments in follow-up studies of adults born preterm-Recommendation of the Adults Born Preterm International Collaboration

BACKGROUND

Of all newborns, 1%-2% are born very preterm (VP; <32 weeks) or with very low birthweight (VLBW; ≤1500 g). Advances in prenatal and neonatal care have substantially improved their survival, and the first generations who have benefited from these advances are now entering middle age. While most lead healthy lives, on average these adults are characterised by a number of adversities. These include cardiometabolic risk factors, airway obstruction, less physical activity, poorer visual function, lower cognitive performance, and a behavioural phenotype that includes inattention and internalising and socially withdrawn behaviour that may affect life chances and quality of life. Outcomes in later adulthood are largely unknown, and identifying trajectories of risk or resilience is essential in developing targeted interventions. Joint analyses of data and maintenance of follow-up of cohorts entering adulthood are essential. Such analyses are ongoing within the Adults Born Preterm International Collaboration (APIC; www.apic-preterm.org). Joint analyses require data harmonisation, highlighting the importance of consistent assessment methodologies.

OBJECTIVE

To present an expert recommendation on Common Core Assessments to be used in follow-up assessments of adults born preterm.

METHODS

Principles of Common Core Assessments were discussed at APIC meetings. Experts for each specific outcome domain wrote the first draft on assessments pertaining to that outcome. These drafts were combined and reviewed by all authors. Consensus was reached by discussion at APIC meetings.

RESULTS

We present a recommendation by APIC experts on consistent measures to be used in adult follow-up assessments.

CONCLUSIONS

The recommendation encompasses both "core" measures which we recommend to use in all assessments of adults born preterm that include the particular outcome. This will allow comparability between time and location. The recommendation also lists optional measures, focusing on current gaps in knowledge. It includes sections on study design, cardiometabolic and related biomarkers, biological samples, life style, respiratory, ophthalmic, cognitive, mental health, personality, quality of life, sociodemographics, social relationships, and reproduction.

COVID-19's impact on faculty and staff at a School of Medicine in the US: what is the blueprint for the future?

Background

The Coronavirus Disease 2019 (COVID-19) caused unprecedented challenges within medical centers, revealing inequities embedded in the medical community and exposing fragile social support systems. While faculty and staff faced extraordinary demands in workplace duties, personal responsibilities also increased. The goal of this study was to understand the impact of the COVID-19 pandemic on personal and professional activities of faculty and staff in order to illuminate current challenges and explore solutions.

Methods

Qualitative, semi-structured group interviews involved faculty and staff at four affiliate sites within the Department of Medicine at the University of Colorado, School of Medicine. Focus groups addressed the impact of COVID-19 on (1) Changes to roles and responsibilities at work and at home, (2) Resources utilized to manage these changes and, (3) Potential strategies for how the Department could assist faculty and staff. Thematic analysis was conducted using an inductive method at the semantic level to form themes and subthemes.

Results

Qualitative analysis of focus group transcripts revealed themes of: (1) Challenges and disparities experienced during the pandemic, (2) Disproportionate impact on women personally and professionally, (3) Institutional factors that contributed to wellness and burnout, and (4) Solutions and strategies to support faculty and staff. Within each of these themes were multiple subthemes including increased professional and personal demands, concern for personal safety, a sense of internal guilt, financial uncertainty, missed professional opportunities, and a negative impact on mentoring. Solutions were offered and included an emphasis on addressing preexisting inequities, the importance of community, and workplace flexibility.

Conclusions

The COVID-19 pandemic created burdens for already challenged faculty and staff in both their personal and professional lives. Swift action and advocacy by academic institutions is needed to support the lives and careers of our colleagues now and in the future.

The effective coupling coefficient for a completed PIN-PMN-PT array

The computation of the electromechanical coupling coefficient (EMCC) of a fully assembled medical ultrasound transducer array is directly computed with closed form expressions. The Levenberg-Marquardt non-linear regression algorithm (LMA) is employed to help confirm the EMCC calculated prediction (k_EFF) and provide statistical insights. The complex electrical impedance spectra of a 1-3 composite array with two matching layers operating at a 3.75 MHz center frequency using PIN-PMN-PT single crystal material is measured in air both before and after oven heating at 160 °C for 15 min. The oven heating produces changes in the EMCC of -4.9%, clamped dielectric constant of -11%, and effective transducer longitudinal velocity of -2.5%. Utilizing the pre- and post-heating array impedance data, the calculated EMCC values from the new closed form expressions agree well with the complete KLM model based LMA, and also exhibit approximately one tenth the error as compared to the formulas for a flat, unloaded transducer.

Measurement of the heat flux normalized spin Seebeck coefficient of thin films as a function of temperature

The spin Seebeck effect (SSE) has generated interest in the thermoelectric and magnetic communities for potential high efficiency energy harvesting applications and spintronic communities as a source of pure spin current. Understanding the underlying mechanisms requires characterization of potential materials across a range of temperatures; however, for thin films, the default measurement of an applied temperature gradient (across the sample) has been shown to be compromised by the presence of thermal resistances. Here, we demonstrate a method to perform low temperature SSE measurements where, instead of monitoring the temperature gradient, the heat flux passing through the sample is measured using two calibrated heat flux sensors. This has the advantage of measuring the heat loss through the sample as well as providing a reliable method to normalize the SSE response of thin film samples. We demonstrate this method with an SiO₂/Fe₃O₄/Pt sample where a semiconducting-insulating transition occurs at the Verwey transition, T_V, of Fe₃O₄ and quantify the thermomagnetic response above and below T_V.

"Health, wealth and achievements of former very premature infants in adult life"

Very preterm survivors born in the early neonatal intensive care era are now in their middle adulthood. The literature from cohort studies and population-linked registries indicate that extreme prematurity is associated with lower educational attainment and income, higher need for social assistance, and lower rates of marriage/partnership and reproduction. In addition, with increasing age, many general and system-specific adverse health outcomes, such as psychiatric problems, hypertension, and cardio-metabolic disorders have emerged, resulting in high cumulative health care costs across the life-span. Yet, a significant majority of adults born preterm are leading productive lives and contributing to society. Although this information may not be directly applicable to survivors of modern neonatal intensive care, there is much to learn from these findings to inform and guide us into designing effective strategies to improve the health and well-being of future very premature infants. The longer-term outcome of more recent survivors remains to be determined.

Algebraic signatures of convex and non-convex codes

A convex code is a binary code generated by the pattern of intersections of a collection of open convex sets in some Euclidean space. Convex codes are relevant to neuroscience as they arise from the activity of neurons that have convex receptive fields. In this paper, we use algebraic methods to determine if a code is convex. Specifically, we use the neural ideal of a code, which is a generalization of the Stanley-Reisner ideal. Using the neural ideal together with its standard generating set, the canonical form, we provide algebraic signatures of certain families of codes that are non-convex. We connect these signatures to the precise conditions on the arrangement of sets that prevent the codes from being convex. Finally, we also provide algebraic signatures for some families of codes that are convex, including the class of intersection-complete codes. These results allow us to detect convexity and non-convexity in a variety of situations, and point to some interesting open questions.