125 research outputs found
Civility and Academic Freedom after Salaita
The 2014 unhiring of Professor Steven Salaita by the University of Illinois raises at least three distinct issues: (1) the right of faculty to speak out in public on matters of public concern; (2) the academic freedom of academic departments to make academic decisions; and (3) the role of civility in education. After differentiating the third issue from the first two, we extend the discussion to other recent cases involving civility in education. The cases range from overt coercion to implicit threats and subtle pressures. We explain that uncivil speech is generally protected by the First Amendment but that this is generally not so within educational contexts. Even where censorship of uncivil speech is legally permissible, however, such censorship is not required and is a serious threat to academic freedom. Educators can promote civility without censorship by modeling and urging mutual respect, engaging students in serious argumentation, and evaluating the academic quality of their arguments
Allopregnanolone as a mediator of affective switching in reproductive mood disorders
Reproductive mood disorders, including premenstrual dysphoria (PMD) and postpartum depression (PPD), are characterized by affective dysregulation that occurs during specific reproductive states. The occurrence of illness onset during changes in reproductive endocrine function has generated interest in the role of gonadal steroids in the pathophysiology of reproductive mood disorders, yet the mechanisms by which the changing hormone milieu triggers depression in susceptible women remain poorly understood
The role of reproductive hormones in postpartum depression
Despite decades of research aimed at identifying the causes of postpartum depression (PPD), PPD remains common, and the causes are poorly understood. Many have attributed the onset of PPD to the rapid perinatal change in reproductive hormones. Although a number of human and nonhuman animal studies support the role of reproductive hormones in PPD, several studies have failed to detect an association between hormone concentrations and PPD. The purpose of this review is to examine the hypothesis that fluctuations in reproductive hormone levels during pregnancy and the postpartum period trigger PPD in susceptible women. We discuss and integrate the literature on animal models of PPD and human studies of reproductive hormones and PPD. We also discuss alternative biological models of PPD to demonstrate the potential for multiple PPD phenotypes and to describe the complex interplay of changing reproductive hormones and alterations in thyroid function, immune function, hypothalamic–pituitary–adrenal (HPA) axis function, lactogenic hormones, and genetic expression that may contribute to affective dysfunction. There are 3 primary lines of inquiry that have addressed the role of reproductive hormones in PPD: nonhuman animal studies, correlational studies of postpartum hormone levels and mood symptoms, and hormone manipulation studies. Reproductive hormones influence virtually every biological system implicated in PPD, and a subgroup of women seem to be particularly sensitive to the effects of perinatal changes in hormone levels. We propose that these women constitute a “hormone-sensitive” PPD phenotype, which should be studied independent of other PPD phenotypes to identify underlying pathophysiology and develop novel treatment targets
Assessing molecular simulation for the analysis of lipid monolayer reflectometry
Using molecular simulation to aid in the analysis of neutron reflectometry
measurements is commonplace. However, reflectometry is a tool to probe
large-scale structures, and therefore the use of all-atom simulation may be
irrelevant. This work presents the first direct comparison between the
reflectometry profiles obtained from different all-atom and coarse-grained
molecular dynamics simulations. These are compared with a traditional model
layer structure analysis method to determine the minimum simulation resolution
required to accurately reproduce experimental data. We find that systematic
limits reduce the efficacy of the MARTINI potential model, while the Berger
united-atom and Slipids all-atom potential models agree similarly well with the
experimental data. The model layer structure gives the best agreement, however,
the higher resolution simulation-dependent methods produce an agreement that is
comparable. Finally, we use the atomistic simulation to advise on possible
improvements that may be offered to the model layer structures, creating a more
realistic monolayer model.Comment: Electronic Supplementary Information (ESI) available: All
analysis/plotting scripts and figure files, allowing for a fully
reproducible, and automated, analysis workflow for the work presented is
available at \url{https://github.com/arm61/sim_vs_trad} (DOI:
10.5281/zenodo.2600729) under a CC BY-SA 4.0 licens
(5R,6S)-4-Isopropyl-5-methyl-6-phenyl-3-propanoyl-2H-1,3,4-oxadiazinan-2-one
The title compound, C16H22N2O3, was synthesized during the course of a study on (1R,2S)-norephedrine-derived 1,3,4-oxadiazinan-2-ones. The conformation adopted by the isopropyl group is pseudo-axial relative to the oxadiazinan core. The allylic strain contributes to this conformational arrangement
Structural and Dynamical Patterns on Online Social Networks: the Spanish May 15th Movement as a case study
The number of people using online social networks in their everyday life is
continuously growing at a pace never saw before. This new kind of communication
has an enormous impact on opinions, cultural trends, information spreading and
even in the commercial success of new products. More importantly, social online
networks have revealed as a fundamental organizing mechanism in recent
country-wide social movements. In this paper, we provide a quantitative
analysis of the structural and dynamical patterns emerging from the activity of
an online social network around the ongoing May 15th (15M) movement in Spain.
Our network is made up by users that exchanged tweets in a time period of one
month, which includes the birth and stabilization of the 15M movement. We
characterize in depth the growth of such dynamical network and find that it is
scale-free with communities at the mesoscale. We also find that its dynamics
exhibits typical features of critical systems such as robustness and power-law
distributions for several quantities. Remarkably, we report that the patterns
characterizing the spreading dynamics are asymmetric, giving rise to a clear
distinction between information sources and sinks. Our study represent a first
step towards the use of data from online social media to comprehend modern
societal dynamics.Comment: 16 pages, 7 figure
Atomistic modelling of scattering data in the Collaborative Computational Project for Small Angle Scattering (CCP-SAS)
The capabilities of current computer simulations provide a unique opportunity to model small-angle scattering (SAS) data at the atomistic level, and to include other structural constraints ranging from molecular and atomistic energetics to crystallography, electron microscopy and NMR. This extends the capabilities of solution scattering and provides deeper insights into the physics and chemistry of the systems studied. Realizing this potential, however, requires integrating the experimental data with a new generation of modelling software. To achieve this, the CCP-SAS collaboration (http://www.ccpsas.org/) is developing open-source, high-throughput and user-friendly software for the atomistic and coarse-grained molecular modelling of scattering data. Robust state-of-the-art molecular simulation engines and molecular dynamics and Monte Carlo force fields provide constraints to the solution structure inferred from the small-angle scattering data, which incorporates the known physical chemistry of the system. The implementation of this software suite involves a tiered approach in which GenApp provides the deployment infrastructure for running applications on both standard and high-performance computing hardware, and SASSIE provides a workflow framework into which modules can be plugged to prepare structures, carry out simulations, calculate theoretical scattering data and compare results with experimental data. GenApp produces the accessible web-based front end termed SASSIE-web, and GenApp and SASSIE also make community SAS codes available. Applications are illustrated by case studies: (i) inter-domain flexibility in two- to six-domain proteins as exemplified by HIV-1 Gag, MASP and ubiquitin; (ii) the hinge conformation in human IgG2 and IgA1 antibodies; (iii) the complex formed between a hexameric protein Hfq and mRNA; and (iv) synthetic 'bottlebrush' polymers
Left ventricular speckle tracking-derived cardiac strain and cardiac twist mechanics in athletes: a systematic review and meta-analysis of controlled studies
Background: The athlete’s heart is associated with physiological remodeling as a consequence of repetitive cardiac loading. The effect of exercise training on left ventricular (LV) cardiac strain and twist mechanics are equivocal, and no meta-analysis has been conducted to date.
Objective: The objective of this systematic review and meta-analysis was to review the literature pertaining to the effect of different forms of athletic training on cardiac strain and twist mechanics and determine the influence of traditional and contemporary sporting classifications on cardiac strain and twist mechanics.
Methods: We searched PubMed/MEDLINE, Web of Science, and ScienceDirect for controlled studies of aged-matched male participants aged 18–45 years that used two-dimensional (2D) speckle tracking with a defined athlete sporting discipline and a control group not engaged in training programs. Data were extracted independently by two reviewers. Random-effects meta-analyses, subgroup analyses, and meta-regressions were conducted.
Results: Our review included 13 studies with 945 participants (controls n = 355; athletes n = 590). Meta-analyses showed no athlete–control differences in LV strain or twist mechanics. However, moderator analyses showed greater LV twist in high-static low-dynamic athletes (d = –0.76, 95% confidence interval [CI] –1.32 to –0.20; p < 0.01) than in controls. Peak untwisting velocity (PUV) was greater in high-static low-dynamic athletes (d = –0.43, 95% CI –0.84 to –0.03; p < 0.05) but less than controls in high-static high-dynamic athletes (d = 0.79, 95% CI 0.002–1.58; p = 0.05). Elite endurance athletes had significantly less twist and apical rotation than controls (d = 0.68, 95% CI 0.19–1.16, p < 0.01; d = 0.64, 95% CI 0.27–1.00, p = 0.001, respectively) but no differences in basal rotation. Meta-regressions showed LV mass index was positively associated with global longitudinal (b = 0.01, 95% CI 0.002–0.02; p < 0.05), whereas systolic blood pressure was negatively associated with PUV (b = –0.06, 95% CI –0.13 to –0.001; p = 0.05).
Conclusion: Echocardiographic 2D speckle tracking can identify subtle physiological differences in adaptations to cardiac strain and twist mechanics between athletes and healthy controls. Differences in speckle tracking echocardiography-derived parameters can be identified using suitable sporting categorizations
Madagascar’s extraordinary biodiversity: Evolution, distribution, and use
Madagascar's biota is hyperdiverse and includes exceptional levels of endemicity. We review the current state of knowledge on Madagascar's past and current terrestrial and freshwater biodiversity by compiling and presenting comprehensive data on species diversity, endemism, and rates of species description and human uses, in addition to presenting an updated and simplified map of vegetation types. We report a substantial increase of records and species new to science in recent years; however, the diversity and evolution of many groups remain practically unknown (e.g., fungi and most invertebrates). Digitization efforts are increasing the resolution of species richness patterns and we highlight the crucial role of field- and collections-based research for advancing biodiversity knowledge and identifying gaps in our understanding, particularly as species richness corresponds closely to collection effort. Phylogenetic diversity patterns mirror that of species richness and endemism in most of the analyzed groups. We highlight humid forests as centers of diversity and endemism because of their role as refugia and centers of recent and rapid radiations. However, the distinct endemism of other areas, such as the grassland-woodland mosaic of the Central Highlands and the spiny forest of the southwest, is also biologically important despite lower species richness. The documented uses of Malagasy biodiversity are manifold, with much potential for the uncovering of new useful traits for food, medicine, and climate mitigation. The data presented here showcase Madagascar as a unique living laboratory for our understanding of evolution and the complex interactions between people and nature. The gathering and analysis of biodiversity data must continue and accelerate if we are to fully understand and safeguard this unique subset of Earth's biodiversity
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