949 research outputs found
Network Analysis of Host-Virus Communities in Bats and Rodents Reveals Determinants of Cross-Species Transmission
Bats are natural reservoirs of several important emerging viruses. Cross-species transmission appears to be quite common among bats, which may contribute to their unique reservoir potential. Therefore, understanding the importance of bats as reservoirs requires examining them in a community context rather than concentrating on individual species. Here, we use a network approach to identify ecological and biological correlates of cross-species virus transmission in bats and rodents, another important host group. We show that given our current knowledge the bat viral sharing network is more connected than the rodent network, suggesting viruses may pass more easily between bat species. We identify host traits associated with important reservoir species: gregarious bats are more likely to share more viruses and bats which migrate regionally are important for spreading viruses through the network. We identify multiple communities of viral sharing within bats and rodents and highlight potential species traits that can help guide studies of novel pathogen emergence
A holistic review of the medical school admission process: examining correlates of academic underperformance
Background: Despite medical school admission committees’ best efforts, a handful of seemingly capable students invariably struggle during their first year of study. Yet, even as entrance criteria continue to broaden beyond cognitive qualifications, attention inevitably reverts back to such factors when seeking to understand these phenomena. Using a host of applicant, admission, and post-admission variables, the purpose of this inductive study, then, was to identify a constellation of student characteristics that, taken collectively, would be predictive of students at-risk of underperforming during the first year of medical school. In it, we hypothesize that a wider range of factors than previously recognized could conceivably play roles in understanding why students experience academic problems early in the medical educational continuum. Methods: The study sample consisted of the five most recent matriculant cohorts from a large, southeastern medical school (n=537). Independent variables reflected: 1) the personal demographics of applicants (e.g., age, gender); 2) academic criteria (e.g., undergraduate grade point averages [GPA], medical college admission test); 3) selection processes (e.g., entrance track, interview scores, committee votes); and 4) other indicators of personality and professionalism (e.g., Mayer-Salovey-Caruso Emotional Intelligence Test™ emotional intelligence scores, NEO PI-R™ personality profiles, and appearances before the Professional Code Committee [PCC]). The dependent variable, first-year underperformance, was defined as ANY action (repeat, conditionally advance, or dismiss) by the college's Student Progress and Promotions Committee (SPPC) in response to predefined academic criteria. This study protocol was approved by the local medical institutional review board (IRB). Results: Of the 537 students comprising the study sample, 61 (11.4%) met the specified criterion for academic underperformance. Significantly increased academic risks were identified among students who 1) had lower mean undergraduate science GPAs (OR=0.24, p=0.001); 2) entered medical school via an accelerated BS/MD track (OR=16.15, p=0.002); 3) were 31 years of age or older (OR=14.76, p=0.005); and 4) were non-unanimous admission committee admits (OR=0.53, p=0.042). Two dimensions of the NEO PI-R™ personality inventory, openness (+) and conscientiousness (−), were modestly but significantly correlated with academic underperformance. Only for the latter, however, were mean scores found to differ significantly between academic performers and underperformers. Finally, appearing before the college's PCC (OR=4.21, p=0.056) fell just short of statistical significance. Conclusions: Our review of various correlates across the matriculation process highlights the heterogeneity of factors underlying students’ underperformance during the first year of medical school and challenges medical educators to understand the complexity of predicting who, among admitted matriculants, may be at future academic risk
High genetic diversity in a potentially vulnerable tropical tree species despite extreme habitat loss
10.1371/journal.pone.0082632PLoS ONE812-POLN
Molecular and cellular mechanisms underlying the evolution of form and function in the amniote jaw.
The amniote jaw complex is a remarkable amalgamation of derivatives from distinct embryonic cell lineages. During development, the cells in these lineages experience concerted movements, migrations, and signaling interactions that take them from their initial origins to their final destinations and imbue their derivatives with aspects of form including their axial orientation, anatomical identity, size, and shape. Perturbations along the way can produce defects and disease, but also generate the variation necessary for jaw evolution and adaptation. We focus on molecular and cellular mechanisms that regulate form in the amniote jaw complex, and that enable structural and functional integration. Special emphasis is placed on the role of cranial neural crest mesenchyme (NCM) during the species-specific patterning of bone, cartilage, tendon, muscle, and other jaw tissues. We also address the effects of biomechanical forces during jaw development and discuss ways in which certain molecular and cellular responses add adaptive and evolutionary plasticity to jaw morphology. Overall, we highlight how variation in molecular and cellular programs can promote the phenomenal diversity and functional morphology achieved during amniote jaw evolution or lead to the range of jaw defects and disease that affect the human condition
Measurement of the charge asymmetry in dileptonic Decays of top quark pairs in pp collisions at √ s = 7 TeV using the ATLAS detector
A measurement of the top-antitop (tt) charge asymmetry is presented using data corresponding to an integrated luminosity of 4.6 fb −1 of LHC pp collisions at a centre- of-mass energy of 7 TeV collected by the ATLAS detector. Events with two charged leptons, at least two jets and large missing transverse momentum are selected. Two observables are studied: A tt/C, based on the reconstructed tt final state. The asymmetries are measured to be
A ll/C = 0.024 +/- 0.015 (stat.) +/- 0.009 (syst.)
Att/C = 0.021 +/- 0.025 (stat.) +/- 0.017 (syst.)
The measured values are in agreement with the Standard Model predictions
Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector
The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV
Anxiety and Depression in Adults with Autism Spectrum Disorder: A Systematic Review and Meta-analysis
Adults with autism spectrum disorder (ASD) are thought to be at disproportionate risk of developing mental health comorbidities, with anxiety and depression being considered most prominent amongst these. Yet, no systematic review has been carried out to date to examine rates of both anxiety and depression focusing specifically on adults with ASD. This systematic review and meta-analysis examined the rates of anxiety and depression in adults with ASD and the impact of factors such as assessment methods and presence of comorbid intellectual disability (ID) diagnosis on estimated prevalence rates. Electronic database searches for studies published between January 2000 and September 2017 identified a total of 35 studies, including 30 studies measuring anxiety (n = 26 070; mean age = 30.9, s.d. = 6.2 years) and 29 studies measuring depression (n = 26 117; mean age = 31.1, s.d. = 6.8 years). The pooled estimation of current and lifetime prevalence for adults with ASD were 27% and 42% for any anxiety disorder, and 23% and 37% for depressive disorder. Further analyses revealed that the use of questionnaire measures and the presence of ID may significantly influence estimates of prevalence. The current literature suffers from a high degree of heterogeneity in study method and an overreliance on clinical samples. These results highlight the importance of community-based studies and the identification and inclusion of well-characterized samples to reduce heterogeneity and bias in estimates of prevalence for comorbidity in adults with ASD and other populations with complex psychiatric presentations
Occupation of racial grief, loss as a resource : learning from ‘The Combahee River Collective Black Feminist Statement'
The methodology of ‘occupation’ through rereading The Combahee River Collective Black Feminist
Statement (The Combahee River Collective, in: James,
Sharpley-Whiting (eds) The Black Feminist Reader.
Blackwell Publishers Ltd., Oxford, pp 261–270, 1977)
demonstrates the necessity of temporal linkages to historical Black feminist texts and the wisdom of Black feminist
situated knowers. This paper argues that racism produces
grief and loss and as long as there is racism, we all remain
in racial grief and loss. However, in stark contrast to the
configuration of racial grief and loss as something to get
over, perhaps grief and loss can be thought about differently, for example, in terms of racial grief and loss as a
resource. This paper questions Western Eurocentric paternalistic responses to Black women’s ‘talk about their
feelings of craziness… [under] patriarchal rule’ (The
Combahee River Collective 1977: 262) and suggests
alternative ways of thinking about the psychological
impact of grief and loss in the context of racism. In this
paper, a Black feminist occupation of racial grief and loss
includes the act of residing within, and the act of working
with the constituent elements of racial grief and loss. The
proposal is that an occupation of racial grief and loss is a
paradoxical catalyst for building a twenty-first century
global intersectional Black feminist movement
Kernel Architecture of the Genetic Circuitry of the Arabidopsis Circadian System
A wide range of organisms features molecular machines, circadian clocks,
which generate endogenous oscillations with ~24 h periodicity and thereby
synchronize biological processes to diurnal environmental fluctuations.
Recently, it has become clear that plants harbor more complex gene regulatory
circuits within the core circadian clocks than other organisms, inspiring a
fundamental question: are all these regulatory interactions between clock genes
equally crucial for the establishment and maintenance of circadian rhythms? Our
mechanistic simulation for Arabidopsis thaliana demonstrates that at least half
of the total regulatory interactions must be present to express the circadian
molecular profiles observed in wild-type plants. A set of those essential
interactions is called herein a kernel of the circadian system. The kernel
structure unbiasedly reveals four interlocked negative feedback loops
contributing to circadian rhythms, and three feedback loops among them drive
the autonomous oscillation itself. Strikingly, the kernel structure, as well as
the whole clock circuitry, is overwhelmingly composed of inhibitory, rather
than activating, interactions between genes. We found that this tendency
underlies plant circadian molecular profiles which often exhibit
sharply-shaped, cuspidate waveforms. Through the generation of these cuspidate
profiles, inhibitory interactions may facilitate the global coordination of
temporally-distant clock events that are markedly peaked at very specific times
of day. Our systematic approach resulting in experimentally-testable
predictions provides insights into a design principle of biological clockwork,
with implications for synthetic biology.Comment: Supplementary material is available at the journal websit
A review of elliptical and disc galaxy structure, and modern scaling laws
A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their
models to describe the radial distribution of stars in `nebulae'. This article
reviews the progress since then, providing both an historical perspective and a
contemporary review of the stellar structure of bulges, discs and elliptical
galaxies. The quantification of galaxy nuclei, such as central mass deficits
and excess nuclear light, plus the structure of dark matter halos and cD galaxy
envelopes, are discussed. Issues pertaining to spiral galaxies including dust,
bulge-to-disc ratios, bulgeless galaxies, bars and the identification of
pseudobulges are also reviewed. An array of modern scaling relations involving
sizes, luminosities, surface brightnesses and stellar concentrations are
presented, many of which are shown to be curved. These 'redshift zero'
relations not only quantify the behavior and nature of galaxies in the Universe
today, but are the modern benchmark for evolutionary studies of galaxies,
whether based on observations, N-body-simulations or semi-analytical modelling.
For example, it is shown that some of the recently discovered compact
elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to
appear in "Planets, Stars and Stellar
Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references
incl. many somewhat forgotten, pioneer papers. Original submission to
Springer: 07-June-201
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