Exotic Dark Matter Search with the Majorana Demonstrator

With excellent energy resolution and ultralow-level radiogenic backgrounds, the high-purity germanium detectors in the Majorana Demonstrator enable searches for several classes of exotic dark matter (DM) models. In this work, we report new experimental limits on keV-scale sterile neutrino DM via the transition magnetic moment from conversion to active neutrinos ν_{s}→ν_{a}. We report new limits on fermionic dark matter absorption (χ+A→ν+A) and sub-GeV DM-nucleus 3→2 scattering (χ+χ+A→ϕ+A), and new exclusion limits for bosonic dark matter (axionlike particles and dark photons). These searches utilize the (1-100)-keV low-energy region of a 37.5-kg y exposure collected by the Demonstrator between May 2016 and November 2019 using a set of ^{76}Ge-enriched detectors whose surface exposure time was carefully controlled, resulting in extremely low levels of cosmogenic activation.

Erratum: Search for Spontaneous Radiation from Wave Function Collapse in the Majorana Demonstrator [Phys. Rev. Lett. 129, 080401 (2022)]

This corrects the article DOI: 10.1103/PhysRevLett.129.080401.

Evidence of Antineutrinos from Distant Reactors Using Pure Water at SNO

The SNO+ Collaboration reports the first evidence of reactor antineutrinos in a Cherenkov detector. The nearest nuclear reactors are located 240 km away in Ontario, Canada. This analysis uses events with energies lower than in any previous analysis with a large water Cherenkov detector. Two analytical methods are used to distinguish reactor antineutrinos from background events in 190 days of data and yield consistent evidence for antineutrinos with a combined significance of 3.5σ.

Final Result of the Majorana Demonstrator's Search for Neutrinoless Double-β Decay in ^{76}Ge

The Majorana Demonstrator searched for neutrinoless double-β decay (0νββ) of ^{76}Ge using modular arrays of high-purity Ge detectors operated in vacuum cryostats in a low-background shield. The arrays operated with up to 40.4 kg of detectors (27.2 kg enriched to ∼88% in ^{76}Ge). From these measurements, the Demonstrator has accumulated 64.5 kg yr of enriched active exposure. With a world-leading energy resolution of 2.52 keV FWHM at the 2039 keV Q_{ββ} (0.12%), we set a half-life limit of 0νββ in ^{76}Ge at T_{1/2}>8.3×10^{25}  yr (90% C.L.). This provides a range of upper limits on m_{ββ} of (113-269) meV (90% C.L.), depending on the choice of nuclear matrix elements.

Search for Spontaneous Radiation from Wave Function Collapse in the Majorana Demonstrator

The Majorana Demonstrator neutrinoless double-beta decay experiment comprises a 44 kg (30 kg enriched in ^{76}Ge) array of p-type, point-contact germanium detectors. With its unprecedented energy resolution and ultralow backgrounds, Majorana also searches for rare event signatures from beyond standard model physics in the low energy region below 100 keV. In this Letter, we test the continuous spontaneous localization (CSL) model, one of the mathematically well-motivated wave function collapse models aimed at solving the long-standing unresolved quantum mechanical measurement problem. While the CSL predicts the existence of a detectable radiation signature in the x-ray domain, we find no evidence of such radiation in the 19-100 keV range in a 37.5 kg-y enriched germanium exposure collected between December 31, 2015, and November 27, 2019, with the Demonstrator. We explored both the non-mass-proportional (n-m-p) and the mass-proportional (m-p) versions of the CSL with two different assumptions: that only the quasifree electrons can emit the x-ray radiation and that the nucleus can coherently emit an amplified radiation. In all cases, we set the most stringent upper limit to date for the white CSL model on the collapse rate, λ, providing a factor of 40-100 improvement in sensitivity over comparable searches. Our limit is the most stringent for large parts of the allowed parameter space. If the result is interpreted in terms of the Diòsi-Penrose gravitational wave function collapse model, the lower bound with a 95% confidence level is almost an order of magnitude improvement over the previous best limit.

Search for Solar Axions via Axion-Photon Coupling with the Majorana Demonstrator

Axions were originally proposed to explain the strong-CP problem in QCD. Through axion-photon coupling, the Sun could be a major source of axions, which could be measured in solid state detection experiments with enhancements due to coherent Primakoff-Bragg scattering. The Majorana Demonstrator experiment has searched for solar axions with a set of ^{76}Ge-enriched high purity germanium detectors using a 33 kg-yr exposure collected between January, 2017 and November, 2019. A temporal-energy analysis gives a new limit on the axion-photon coupling as g_{aγ}<1.45×10^{-9}  GeV^{-1} (95% confidence level) for axions with mass up to 100  eV/c^{2}. This improves laboratory-based limits between about 1  eV/c^{2} and 100  eV/c^{2}.

Systematic review of student anxiety and performance during objective structured clinical examinations

INTRODUCTION

Test anxiety is well studied in higher education, but studies primarily concern traditional assessments, such as written examinations. As use of objective structured clinical examination (OSCE) in pharmacy education increases, a closer examination of non-cognitive factors such as test anxiety is warranted. The purpose of this review was to determine the association between OSCE-associated test anxiety with OSCE performance in health professional students.

METHODS

A literature search was conducted to identify peer-reviewed literature concerning test anxiety in health professional students associated with OSCE. Investigators searched for a combination of OSCE-related terms with anxiety-related terms using PubMed. Articles were included if they assessed OSCE-related anxiety by quantitative or qualitative methods. Data extracted from eligible articles included demographic data, type of the anxiety survey, associations between OSCE-related anxiety and performance, and other student-factors associated with OSCE-related anxiety.

RESULTS

The literature search yielded 339 articles. Nine articles met eligibility criteria and were included in the review. Results included students from medical, pharmacy, dental, and nursing professional programs. Anxiety was assessed via multiple scales. Six out of the eight studies assessing the relationship OSCE-related anxiety and OSCE performance found no association between the two measures. Contrary to literature concerning test anxiety in higher education, female gender was not associated with OSCE-related anxiety.

CONCLUSION

OSCE-related anxiety appears to have minimal to no influence on student performance. Future studies should utilize standardized anxiety assessments and should seek to understand anxiety's effects on student wellbeing and burnout.

Leveraging telecommuting pharmacists in the post-COVID-19 world

In response to the coronavirus disease 2019 (COVID-19) pandemic, many industries, including pharmacy, rapidly expanded the use of telecommuting workers to assure business continuity and address social distancing needs. Advances in electronic health records and telepharmacy over the past 2 decades enabled pharmacy leaders to easily adapt their practice models to allow for telecommuting alternatives during the pandemic. While these changes were generally intended to be part of the short-term response, the sustained expansion of telecommuting within the pharmacy profession merits further exploration. Documented experience with telepharmacy and telehealth indicate a wide array of clinical and operational pharmacist activities that could be conducted by telecommuters. In addition, experience with telecommuters in other industries suggests potential benefits ranging from improving pharmacists' work-life balance to mitigating postpandemic financial burden. Health care organizations should consider integrating part-time telecommuter pharmacists into contemporary practice models to address other frontline issues and facilitate ongoing expansion of clinical pharmacy services to meet emerging patient needs.

An Objective Structured Clinical Examination to Assess Competency Acquired During an Introductory Pharmacy Practice Experience

Objective. To evaluate the use of an objective structured clinical examinations (OSCE) to assess clinical competency acquired during an off-campus introductory pharmacy practice experience (IPPE). Methods. Third-year pharmacy students completed an IPPE in transitions of care and completed 24 experiential contact hours at one of 17 practice sites. Students were assessed using two OSCEs, the first occurring prior to beginning an off-site IPPE (pre-experience OSCE) and the second occurring after completion of the off-site IPPE (post-experience OSCE). Each OSCE consisted of 10 stations and covered five graded competency domains. The primary outcome was the degree of change in student performance from the pre-experience OSCE to the post-experience OSCE. Secondary outcomes included changes in each graded domain, OSCE pass rate, and failure conversion rate. Results. Of 111 students, 109 completed both the pre- and post-experience OSCE. Significant improvements were observed in overall score and cohort pass rate. Overall scores improved from 80 for the pre-experience OSCE to 87 for the post-experience OSCE. The OSCE pass rate also improved from 47% to 84%. Conclusion. Although preceptor evaluations have traditionally served as the primary summative assessment for IPPE and APPE, this study indicates that OSCEs may be a reliable alternative to assess clinical competency acquired from off-site practice experiences.

Instructional and Assessment Redesign of a Sterile Compounding Course Using Immersive Simulation

Objective. To revise a traditional sterile compounding course to include content, competencies, and immersive simulations relevant to the current practice of sterile compounding pharmacy. Methods. Faculty and staff at the University of North Texas System College of Pharmacy made significant revisions to an existing sterile compounding course. Instruction was provided in didactic and laboratory sessions and delivered in three modules: fundamental skills, integration of skills and knowledge, and exceptions and specialty topics. Integration laboratory sessions consisted primarily of repetitive but increasingly difficult simulations that included both technician and pharmacist activities. Assessment methods included checkpoint assessments, a mock objective structured clinical examination (OSCE), a written examination, and a final comprehensive OSCE. Effectiveness of the course redesign was assessed by comparing student performance on assessments, overall course performance, and student perceptions extracted from the student course evaluation. Results. Of the 364 students enrolled in the sterile compounding course across four terms, 156 were in the pre-implementation cohort (cohort 1) and 208 were in the post-implementation cohort (cohort 2). Two hundred twenty-eight students completed the course evaluation. Course evaluations significantly demonstrated students' improved perceptions related to seven of 11 survey elements, most notably, critical thinking, integration of concepts, and students feeling challenged. Student performance on laboratory summative assessments also improved. However, written examination scores did not change. Conclusion. This novel sterile compounding course provided a practice-oriented blueprint for instruction and assessment of sterile compounding.

Fish consumption is associated with school performance in children in a non-linear way: Results from the German cohort study KiGGS

Introduction

How the long-chain fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in the diet permitted human brain evolution, and how much our brains need today to function optimally are still hot topics for debate. DHA and EPA are considered as semi-essential because only insufficient amounts can be produced from other nutrients, such that they must be ingested with the diet. However, the Dietary Reference Intake of DHA and EPA, or of fish containing these fatty acids, has not yet been established. Eating fish is often recommended and generally considered beneficial for health and cognitive development in children and adolescents. For this study, data from a large cohort study were analysed to assess the association between fish consumption and cognitive school performance in children and adolescents.

Methods

Data from the German cohort of children and adolescent health KiGGS, which was conducted 2003-06 and included more than 17 000 children, were analysed. Ordered logistic regressions were performed to test for associations between fish intake and school performance. Potential confounders were included in the models.

Results

A statistically significant association was found between an intake of 8 g of fish per day and the probability of increasing the final grade in German [odds ratio (OR) 1.193, 95% confidence interval (CI) 1.049-1.358] and mathematics (OR 1.16, 95% CI 1.022-1.317) by one point, compared to no or very limited fish consumption. For the outcome German, higher levels of fish intake also showed a positive effect. These relationships were not linear but tended to decrease again at higher doses of fish.

Discussion

Our result confirms previous reports of a positive association between fish intake and school performance. Interestingly, this relationship was not linear but tended to decrease again in the highest categories of fish intake. We hypothesize that mercury or other pollutants in the fish could be detrimental at high levels. As only half of all children met the minimal fish intake recommendations, fish consumption should be promoted more strongly in children to meet the minimal requirements of long-chain polyunsaturated fatty acids.

Lay Summary

Polyunsaturated fatty acids like DHA and EPA that are present in fish are essential for a healthy human brain development. We found a U-shaped association between fish intake and school performance in children. We hypothesize that mercury or other pollutants in the fish could be detrimental at high intake levels.

Successful Remediation of an Advanced Pharmacy Practice Experience for an At-risk Student

Objective. To describe a successful remediation for an Acute Care Medicine advanced pharmacy practice experience (APPE) in a student with multiple learning deficits. Methods. A literature review of pharmacy and medical experiential remediation was conducted to identify best practices to implement prior to designing the remediation for our student case. Based on this search and experience as preceptors, a three-phase remediation was designed: one week for assessment, two weeks for development of learning skills and strategies and six weeks for an on-campus APPE. Success of the remediation was determined by student performance, as defined by the APPE preceptor, in all relevant 2013 Center for the Advancement of Pharmacy Education (CAPE) educational outcomes. Results. Baseline assessment indicated that the student was below minimal competency in six of 13 relevant 2013 CAPE educational outcomes. Upon completion of the three-part remediation, the student repeated the Acute Care Medicine APPE, achieving better than minimal competency in all 13 outcomes. The student demonstrated significant improvement in nine of 13 CAPE educational outcomes. Conclusion. This student case provides a novel and successful blueprint for remediation of APPE. However, more evidence-based literature is needed to guide educators in experiential remediation.

First Limit on the Direct Detection of Lightly Ionizing Particles for Electric Charge as Low as e/1000 with the Majorana Demonstrator

The Majorana Demonstrator is an ultralow-background experiment searching for neutrinoless double-beta decay in ^{76}Ge. The heavily shielded array of germanium detectors, placed nearly a mile underground at the Sanford Underground Research Facility in Lead, South Dakota, also allows searches for new exotic physics. Free, relativistic, lightly ionizing particles with an electrical charge less than e are forbidden by the standard model but predicted by some of its extensions. If such particles exist, they might be detected in the Majorana Demonstrator by searching for multiple-detector events with individual-detector energy depositions down to 1 keV. This search is background-free, and no candidate events have been found in 285 days of data taking. New direct-detection limits are set for the flux of lightly ionizing particles for charges as low as e/1000.

Search for Neutrinoless Double-β Decay in ^{76}Ge with the Majorana Demonstrator

The Majorana Collaboration is operating an array of high purity Ge detectors to search for neutrinoless double-β decay in ^{76}Ge. The Majorana Demonstrator comprises 44.1 kg of Ge detectors (29.7 kg enriched in ^{76}Ge) split between two modules contained in a low background shield at the Sanford Underground Research Facility in Lead, South Dakota. Here we present results from data taken during construction, commissioning, and the start of full operations. We achieve unprecedented energy resolution of 2.5 keV FWHM at Q_{ββ} and a very low background with no observed candidate events in 9.95 kg yr of enriched Ge exposure, resulting in a lower limit on the half-life of 1.9×10^{25}  yr (90% C.L.). This result constrains the effective Majorana neutrino mass to below 240-520 meV, depending on the matrix elements used. In our experimental configuration with the lowest background, the background is 4.0_{-2.5}^{+3.1}  counts/(FWHM t yr).

New Limits on Bosonic Dark Matter, Solar Axions, Pauli Exclusion Principle Violation, and Electron Decay from the Majorana Demonstrator

We present new limits on exotic keV-scale physics based on 478 kg d of Majorana Demonstrator commissioning data. Constraints at the 90% confidence level are derived on bosonic dark matter (DM) and solar axion couplings, Pauli exclusion principle violating (PEPV) decay, and electron decay using monoenergetic peak signal limits above our background. Our most stringent DM constraints are set for 11.8 keV mass particles, limiting g_{Ae}<4.5×10^{-13} for pseudoscalars and (α^{'}/α)<9.7×10^{-28} for vectors. We also report a 14.4 keV solar axion coupling limit of g_{AN}^{eff}×g_{Ae}<3.8×10^{-17}, a 1/2β^{2}<8.5×10^{-48} limit on the strength of PEPV electron transitions, and a lower limit on the electron lifetime of τ_{e}>1.2×10^{24}  yr for e^{-}→ invisible.

Significant reduction in vancomycin-resistant enterococcus colonization and bacteraemia after introduction of a bleach-based cleaning-disinfection programme

BACKGROUND

Vancomycin-resistant enterococcus (VRE) colonization and infection have increased at our hospital, despite adherence to standard VRE control guidelines.

AIM

We implemented a multi-modal, hospital-wide improvement programme including a bleach-based cleaning-disinfection programme ('Bleach-Clean'). VRE colonization, infection and environmental contamination were compared pre and post implementation.

METHODS

The programme included a new product (sodium hypochlorite 1000 ppm + detergent), standardized cleaning-disinfection practices, employment of cleaning supervisors, and modified protocols to rely on alcohol-based hand hygiene and sleeveless aprons instead of long-sleeved gowns and gloves. VRE was isolated using chromogenic agar and/or routine laboratory methods. Outcomes were assessed during the 6 months pre and 12 months post implementation, including proportions (per 100 patients screened) of VRE colonization in high-risk wards (HRWs: intensive care, liver transplant, renal, haematology/oncology); proportions of environmental contamination; and episodes of VRE bacteraemia throughout the entire hospital.

FINDINGS

Significant reductions in newly recognized VRE colonizations (208/1948 patients screened vs 324/4035, a 24.8% reduction, P = 0.001) and environmental contamination (66.4% reduction, P = 0.012) were observed, but the proportion of patients colonized on admission was stable. The total burden of inpatients with VRE in the HRWs also declined (median percentage of colonized inpatients per week, 19.4% vs 17.3%, P = 0.016). Hospital-wide VRE bacteraemia declined from 14/2935 patients investigated to 5/6194 (83.1% reduction; P < 0.001), but there was no change in vancomycin-susceptible enterococcal bacteraemia (P = 0.54).

CONCLUSION

The Bleach-Clean programme was associated with marked reductions in new VRE colonizations in high-risk patients, and VRE bacteraemia across the entire hospital. These findings have important implications for VRE control in endemic healthcare settings.

Comment on "The Brain of LB1, Homo floresiensis"

Endocast analysis of the brain Homo floresiensis by Falk et al. (Reports, 8 April 2005, p. 242) implies that the hominid is an insular dwarf derived from H. erectus, but its tiny cranial capacity cannot result from normal dwarfing. Consideration of more appropriate microcephalic syndromes and specimens supports the hypothesis of modern human microcephaly.

Direct search for charged higgs bosons in decays of top quarks

We present a search for charged Higgs bosons in decays of pair-produced top quarks in pp collisions at sqrt[s] = 1.8 TeV recorded by the D0 detector at the Fermilab Tevatron collider. With no evidence for signal, we exclude most regions of the ( M(H+/-),tan(beta)) parameter space where the decay t--> H(+)b has a branching fraction >0.36 and B(H+/--->tau(nu)(tau)) is large.

Search for new physics using QUAERO: a general interface to D0 event data

We describe QUAERO, a method that (i) enables the automatic optimization of searches for physics beyond the standard model, and (ii) provides a mechanism for making high energy collider data generally available. We apply QUAERO to searches for standard model WW, ZZ, and t t macro production, to searches for these objects produced through a new heavy resonance, and to the first direct search for W'-->WZ. Through this interface, we make three data sets collected by the D0 experiment at square root of [s] = 1.8 TeV publicly available.

Peripartum sex steroid profiles and endocrine correlates of postpartum maternal behavior in captive gorillas (Gorilla gorilla gorilla)

An association between pregnancy levels of estrogen and progesterone and maternal behavior has been demonstrated in several taxonomic orders of nonprimate and primate mammals, but has not so far been investigated in the gorilla. In this study we investigated whether prepartum titers of urinary estrone conjugates (E1C) or pregnanediol-3alpha-glucuronide (PdG) were related to postpartum maternal behavior in eight multiparous Western lowland gorilla females (Gorilla gorilla gorilla) housed in four zoological gardens. Urine samples were collected from each study animal for 14 days prepartum and 14 days postpartum, and measures of maternal responsiveness were scored during the first 15 days postpartum. Urine samples were assayed with radioimmunoassay for E1C and PdG. Results for the peripartum profiles of urinary E1C, as well as postpartum profiles of PdG, agree with previous findings for the gorilla, while results for late-pregnancy profiles of urinary PdG were inconclusive in confirming a prepartum increase or decrease. Neither prepartum levels of E1C or PdG, nor the E1C/PdG ratio were found to be related to measures of postpartum maternal behavior. This lack of association between late-pregnancy E1C titers per se and postpartum maternal behavior is contrary to findings in nonprimate and other primate species.

Search for heavy particles decaying into electron-positron pairs in pp collisions

We present results of searches for technirho (rho(T)), techniomega (omega(T)), and Z' particles, using the decay channels rho(T),omega(T),Z'-->e(+)e(-). The search is based on 124.8 pb(-1) of data collected by the D0 detector at the Fermilab Tevatron during 1992-1996. In the absence of a signal, we set 95% C.L. upper limits on the cross sections for the processes pp-->rho(T),omega(T),Z'-->e(+)e(-) as a function of the mass of the decaying particle. For certain model parameters, we exclude the existence of degenerate rho(T) and omega(T) states with masses below about 200 GeV. We exclude a Z' with mass below 670 GeV, assuming that it has the same couplings to fermions as the Z boson.

Is male-infant caretaking related to paternity and/or mating activities in wild Barbary macaques (Macaca sylvanus)?

In species with a promiscuous mating system, the functions of male-infant caretaking remain unclear in the absence of genetic paternity tests. We tested paternal investment and hypotheses concerning reproductive tactics in wild groups of Barbary macaques, including results of genetic paternity tests. Our study revealed that male-infant caretaking was not related to the probability of paternity. In principle, males could use access to females to estimate paternity. However, we found that mating success was not related to paternity, so males could invest in infants that they had not sired, and caretaking of non-offspring was actually observed. Accordingly, males might be 'deceived' with respect to their paternal investment. In that case, one would expect a positive relation between mating success and the subsequent rate of male caretaking of infants. Such a relation is also lacking, leading to comprehensive rejection of the paternal investment hypothesis in Barbary macaques. By contrast, there was evidence that males showing infant care achieved higher mating frequencies than other males with the mothers of the relevant infants. Thus, male Barbary macaques do not show a 'mate-then-care' pattern, but they do exhibit a 'care-then-mate' pattern.

Quasi-model-independent search for new high p(T) physics at D0

We apply a quasi-model-independent strategy ("Sleuth") to search for new high p(T) physics in approximately 100 pb(-1) of pp collisions at square root of (s) = 1.8 TeV collected by the D0 experiment during 1992-1996 at the Fermilab Tevatron. We systematically analyze many exclusive final states and demonstrate sensitivity to a variety of models predicting new phenomena at the electroweak scale. No evidence of new high p(T) physics is observed.

Molecular phylogeny of the lemur family cheirogaleidae (primates) based on mitochondrial DNA sequences

Cheirogaleidae currently comprises five genera whose relationships remain contentious. The taxonomic status and phylogenetic position of both Mirza coquereli and Allocebus trichotis are still unclear. The taxonomic status of the recently discovered Microcebus ravelobensis (a sympatric sibling species of Microcebus murinus) and its phylogenetic position also require further examination. A approximately 2.4-kb mitochondrial DNA sequence including part of the COIII gene, complete ND3, ND4L, and ND4 genes, and 5 tRNAs was used to clarify relationships among cheirogaleids. Mirza and Microcebus form a clade representing the sister group of Allocebus, with a clade containing Cheirogaleus major and Cheirogaleus medius diverging first. M. ravelobensis and Microcebus rufus form a subclade within Microcebus, with M. murinus as its sister group. The molecular data support the generic status of Mirza coquereli and species-level divergence of M. ravelobensis. Furthermore, "M. rufus" may well represent more than one species.

Ratio of jet cross sections at square root of s = 630 GeV and 1800 GeV

The D0 Collaboration has measured the inclusive jet cross section in barpp collisions at square root of s = 630 GeV. The results for pseudorapidities (eta)<0.5 are combined with our previous results at square root of s = 1800 GeV to form a ratio of cross sections with smaller uncertainties than either individual measurement. Next-to-leading-order QCD predictions show excellent agreement with the measurement at 630 GeV; agreement is also satisfactory for the ratio. Specifically, despite a 10% to 15% difference in the absolute magnitude, the dependence of the ratio on jet transverse momentum is very similar for data and theory.

Ratios of multijet Cross Sections in p p collisions at radical(s) = 1.8 TeV

We report on a study of the ratio of inclusive three-jet to inclusive two-jet production cross sections as a function of total transverse energy in p&pmacr; collisions at a center-of-mass energy sqrt[s] = 1.8 TeV, using data collected with the D0 detector during the 1992-1993 run of the Fermilab Tevatron Collider. The measurements are used to deduce preferred renormalization scales in perturbative O(alpha(3)(s)) QCD calculations in modeling soft-jet emission.

Inclusive jet production in pp(macro) collisions

We report a new measurement of the pseudorapidity (eta) and transverse-energy ( E(T)) dependence of the inclusive jet production cross section in pp(macro) collisions at square root of s = 1.8 TeV using 95 pb(-1) of data collected with the D0 detector at the Fermilab Tevatron. The differential cross section d(2)sigma/(dE(T)d eta) is presented up to eta = 3, significantly extending previous measurements. The results are in good overall agreement with next-to-leading order predictions from QCD and indicate a preference for certain parton distribution functions.

Search for large extra dimensions in dielectron and diphoton production

We report a search for effects of large extra spatial dimensions in pp collisions at a center-of-mass energy of 1.8 TeV with the D0 detector, using events containing a pair of electrons or photons. The data are in good agreement with the expected background and do not exhibit evidence for large extra dimensions. We set the most restrictive lower limits to date, at the 95% C.L. on the effective Planck scale between 1.0 and 1.4 TeV for several formalisms and numbers of extra dimensions.

Phylogenetic history of sifakas (Propithecus: lemuriformes) derived from mtDNA sequences

The sifakas (Propithecus) include three species containing up to 10 described subspecies, whose evolutionary relationships remain contentious. In particular, it is unclear whether P. verreauxi deckeni and P.v. coronatus populations are differentiated at the subspecific level. Furthermore, the taxonomic status of the recently discovered P. tattersalli and its phylogenetic position also require further examination. About 2,400 bp of mitochondrial DNA sequence data from part of the COIII gene, together with complete genes for ND3, ND4L, ND4, and five tRNAs, were used to clarify relationships among Propithecus species and subspecies. All analyses group Avahi as the sister group to all sifakas. P. diadema is placed as a sister group to all other Propithecus. Among the remaining sifakas, one subclade is formed by Puv. coquereli and P. tattersalli, while P.v. verreauxi, P.v. deckeni, and P.v. coronatus form the second subclade. All analyses fail to resolve P.vu. coronatus and P.v. deckeni into separate monophyletic lineages. Based on pairwise distance comparisons and tree topology, we conclude that P. tattersalli does not represent a distinct species and that P.v. deckeni and P.v. coronatus do not deserve subspecific rank. On the other hand, our analyses indicate that P.v. coquereli may well represent a separate species.

Relationships among brown lemurs (Eulemur fulvus) based on mitochondrial DNA sequences

The brown lemurs (Eulemur fulvus) include seven subspecies, whose evolutionary relationships remain contentious. In particular, it is unclear whether the Malagasy and Comorian E. f. fulvus populations are differentiated at the subspecific level (E. f. mayottensis). Furthermore, it has been suggested that E. f. collaris and E. f. albocollaris are separate species. Analyses of approximately 2400 bp of mitochondrial DNA sequence data from part of the COIII gene, together with complete genes for ND3, ND4L, and ND4 and 5 tRNAs, resolved 34 E. fulvus specimens into six clades: ((albocollaris, collaris) (rufus (rufus (fulvus/mayottensis (albifrons/fulvus/sanfordi))))). Based on the information available and our analyses we conclude that E. f. albocollaris and E. f. collaris do not represent species distinct from E. fulvus and that Comorian brown lemurs do not deserve subspecific rank. No genetic differentiation was detected between E. f. albifrons and E. f. sanfordi; on the other hand, there are obviously two separate lineages of E. f. rufus.

The major histocompatibility complex and mate choice: inbreeding avoidance and selection of good genes

It has been known for decades that MHC genes play a critical role in the cellular immune response, but only recent research has provided a better understanding of how these molecules might affect mate choice. Original studies in inbred mouse strains revealed that mate choice was influenced by MHC dissimilarity. Detection of MHC differences between individuals in these experiments was related to olfactory cues, primarily in urine. Recent studies in humans have shown an analogous picture of MHC-based mating. Taken together, these findings could support either the hypothesis of MHC-based inbreeding avoidance or the hypothesis of MHC-related avoidance of reproductive failure, since studies in mice, humans and pigtailed macaques have shown that parental sharing of certain MHC alleles correlates with frequent spontaneous abortion or prolonged intergestational intervals. Data from many mammalian species clearly demonstrate that reproductive failure occurs as a result of inbreeding. Therefore, MHC similarity might serve as an indicator of genome-wide relatedness. In contrast, increased fitness due to the presence of individual MHC alleles in a pathogenic environment could explain MHC-based selection of currently good genes. Specifically, the physical condition of long-living animals depends on the ability to respond to immunological challenge and an individual's MHC alleles determine the response, since, unlike the T cell receptors, MHC alleles are not somatically recombined. Therefore, sexual selection of condition-dependent traits during mate choice could be used to select successful MHC alleles, thereby providing offspring with a higher relative immunity in their pathogenic environment.

Cathemerality in the mongoose lemur, Eulemur mongoz

Results of a 10 month study of the mongoose lemur (Eulemur mongoz) at Anjamena are presented. The activity pattern is documented in detail for both wet and dry seasons based on observations conducted over the entire 24 h period. E. mongoz was found to be cathemeral throughout the year but exhibited shifts towards more diurnal activity in the wet season and more nocturnal activity in the dry season. The cathemeral activity pattern in the mongoose lemur appears to be coordinated with sunrise, sunset, and day length and modulated by an inhibitory effect of low nocturnal light intensity in the forest during the wet season, resulting in mainly diurnal activity. Temperature and rainfall may also influence the activity pattern. Few advantages to food-related behavior appear to derive from this activity pattern, although resource accessibility may be enhanced by nocturnal behavior in the dry season, leading to reduction in interspecific competition. Cathemerality may also represent a behavioral thermoregulatory mechanism allowing the mongoose lemur to conserve energy by being active during the cool nights of the dry season. In addition, nocturnal behavior in the dry season probably allows avoidance of predation by raptors at the time of year when least protection is afforded by vegetation.

Rate of metabolism in the smallest simian primate, the pygmy marmoset (Cebuella pygmaea)

Rate of metabolism was measured with six adult pygmy marmosets (Cebuella pygmaea) at regulated ambient temperatures ranging between 20 degrees C and 35 degrees C. A novel combined nest box and metabolic chamber was designed to allow nighttime measurements on immobile animals in their home cage without disturbance. The basal rate of metabolism (BMR) was 98 ml O2 h-1, representing 74% of the value expected from the equation of McNab [Quarterly Review of Biology 63:25-54, 1988] relative to body mass. The thermoneutral zone was approximately 27-34 degrees C. Below the lower critical temperature (27-28 degrees C), thermal conductance (12.9 ml O2 h-1 degree C-1) was close to the predicted value. Body temperature ranged between 34.9 degrees C and 35.5 degrees C at night. When two animals rested together overnight in the nest box, the lower critical temperature was slightly lowered, and individual energy expenditure at 20-21 degrees C was reduced by about 34%. The basal rate of metabolism of C. pygmaea is much lower than reported in an earlier study based on daytime measurements but agrees with values reported from a more recent study conducted at night with a classical metabolic chamber. In order to compare the BMR of C. pygmaea with that of other primates, 23 species were included in a comparative study taking into account both phylogeny and body mass (independent contrasts approach). The scaling exponent of BMR to body mass obtained was indistinguishable from that published for eutherian mammals in general. Cebuella and Callithrix exhibit the lowest basal rates known for simians. This trait may possibly be linked to the natural diet, which includes a large proportion of gums that are difficult to digest, but additional metabolic studies on primates are needed for further examination of its adaptive significance.

Probing Balitsky-Fadin-Kuraev-Lipatov dynamics in the dijet cross section at large rapidity intervals in pp collisions at sqrt[s]=1800 and 630 GeV

Inclusive dijet production at large pseudorapidity intervals (Deltaeta) between the two jets has been suggested as a regime for observing Balitsky-Fadin-Kuraev-Lipatov (BFKL) dynamics. We have measured the dijet cross section for large Deltaeta in pp collisions at sqrt[s]=1800 and 630 GeV using the D0 detector. The partonic cross section increases strongly with the size of Deltaeta. The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of alphaBFKL(20 GeV)=1.65+/-0.07.

Measurement of the W-->taunu production cross section in pp collisions at square root s=1.8 TeV

We report on a measurement of sigma(pp-->W+X)B(W-->taunu) in pp collisions at sqrt[s]=1.8 TeV at the Fermilab Tevatron. The measurement is based on an integrated luminosity (lum) of 18 pb-1 of data collected with the D0 detector during 1994-1995. We find that sigma(pp-->W+X)B(W-->taunu)=2.22+/-0.09 (stat)+/-0. 10 (syst)+/-0.10 (lum) nb. Lepton universality predicts that the ratio of the tau and electron electroweak charged current couplings to the W boson, gWtau/gWe, be unity. We find gWtau/gWe=0.980+/-0.031, in agreement with lepton universality.

Improved branching ratio measurement for the decay K(0)(L) --> &mgr;(+)&mgr;(-)

We report results from Experiment 871, performed at the BNL AGS, of a measurement of the branching ratio K(0)(L)-->&mgr;(+)&mgr;(-) with respect to the CP-violating mode K(0)(L)-->pi(+)pi(-). This experiment detected over 6200 candidate &mgr;(+)&mgr;(-) events, a factor of 6 more than that seen in all previous measurements combined. The resulting branching ratio gamma(K(0)(L)-->&mgr;(+)&mgr;(-))/gamma(K(0)(L)-->pi(+)pi(-)) = (3. 474+/-0.057)x10(-6) leads to a branching fraction B(K(0)(L)-->&mgr;(+)&mgr;(-)) = (7.18+/-0.17)x10(-9), which is consistent with the current world average, and reduces the uncertainty in this decay mode by a factor of 3.

'Friendship' for fitness in chimpanzees?

It has been repeatedly suggested that primates trade social services for fitness benefits in their relationships with the opposite sex. We tested this proposal in a colony of captive chimpanzees, Pan troglodytes, by examining behavioural data on grooming, agonistic support and food sharing in relation to genetically established paternity. We found no support for the notion of trade. First, males did not sire more offspring with females that they actively groomed more frequently, that they supported more often or with which they shared food more frequently. Correspondingly, females did not give birth to more offspring sired by males from which they received more services. Second, males that showed more affiliative behaviour towards females in general did not sire more progeny. Furthermore, females did not bear more offspring sired by males to which they themselves directed more sociopositive behaviour. Results from this captive colony are compatible with those reported for chimpanzees under natural conditions. Copyright 1999 The Association for the Study of Animal Behaviour.