Fast approach to the Tracy-Widom law at the edge of GOE and GUE

We study the rate of convergence for the largest eigenvalue distributions in the Gaussian unitary and orthogonal ensembles to their Tracy-Widom limits. We show that one can achieve an $O(N^{-2/3})$ rate with particular choices of the centering and scaling constants. The arguments here also shed light on more complicated cases of Laguerre and Jacobi ensembles, in both unitary and orthogonal versions. Numerical work shows that the suggested constants yield reasonable approximations, even for surprisingly small values of N.Comment: Published in at http://dx.doi.org/10.1214/11-AAP819 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

Exploitative leaders incite intergroup warfare in a social mammal

This is the final version. Available on open access from the National Academy of Sciences via the DOI in this recordCollective conflicts among humans are widespread, though often highly destructive. A classic explanation for the prevalence of such warfare is leadership by self-serving individuals that reap the benefits of conflict while other members of society pay the costs. Here, we show that leadership of this kind can also explain the evolution of collective violence in certain animal societies. We first extend the classic Hawk-Dove model of the evolution of animal aggression to consider cases in which a subset of individuals within each group may initiate fights in which all group members become involved. We show that leadership of this kind, when combined with inequalities in the payoffs of fighting, can lead to the evolution of severe intergroup aggression, with negative consequences for population mean fitness. We test our model using long-term data from wild banded mongooses, a species characterised by frequent intergroup conflicts that have very different fitness consequences for male and female group members. The data show that aggressive encounters between groups are initiated by females, who gain fitness benefits from mating with extra-group males in the midst of battle, whereas the costs of fighting are borne chiefly by males. In line with the model predictions, the result is unusually severe levels of intergroup violence. Our findings suggest that the decoupling of leaders from the costs that they incite amplifies the destructive nature of intergroup conflict.Natural Environment Research Council (NERC

The state of international collaboration for health systems research: what do publications tell?

AIM: International collaboration for health system development has been identified as a critical input to meet pressing global health needs. North-South collaboration has the potential to benefit both parties, while South-South collaboration offers promise to strengthen capacity rapidly and efficiently across developing countries. There is an emerging trend to analyze the fruits of such collaboration. This paper builds on this trend by applying an innovative concept-based bibliometric method to identify the international scope of collaboration within the field of health policy and systems research. Two key questions are addressed: to what extent are papers comparing developing countries as against reporting on single country studies? To what extent are papers in either case being produced by researchers within their respective countries or through North-South or South-South collaboration? METHODS: A total of 8,751 papers published in Medline between 1999 and 2003 with data on health systems and policies in developing countries were identified and content-analyzed using an innovative concept-based search technology. A sample of 13% of papers was used to identify the corresponding institution and countries covered. The sampled data was then analyzed by income group. RESULTS: Papers with an international, cross-country focus account for only 10% of the total. Just over a third of all papers are led by upper middle income country authors, closely followed by authors from high income countries. Just under half of all papers target low income countries. Cross-country papers are led mostly by institutions in high income countries, with 74% of the total. Only seven countries concentrate 60% of the papers led by developing country institutions. Institutions in the United States and the United Kingdom concentrate between them as many as 68% of the papers led by high income countries. Only 11% of all single-country papers and 21% of multi-country studies are the product of South-South collaboration. Health Financing is the topic with the greatest international scope, with 26% of all papers in the topic. Topics such as Costing and Cost Effectiveness, Finance, Sector Analysis and Insurance, regardless of their national or international scope, are led in 38% to 54% of cases by high income authors. CONCLUSION: While there is modest health systems research capacity in many developing countries for single country studies, capacity is severely limited for multi-country studies. While North-South collaboration is important, the number of international studies is still very limited to produce the kind of knowledge required to learn from experiences across countries. The fact that lead institutions as well as study countries are concentrated in a handful of mostly middle income countries attests to great disparities in research capacity. However, disparities in research capacity and interest are also evident in the North. It is urgent to build cross-country research capacity including appropriate forms of South-South and North-South collaboration

An initial overview of the extent and structure of recent star formation within the Serpens Molecular Cloud using Gaia Data Release 2

This is the final version. Available from American Astronomical Society / IOP Publishing via the DOI in this record.The dense clusters within the Serpens Molecular Cloud are among the most active regions of nearby star formation. In this paper, we use Gaia DR2 parallaxes and proper motions to statistically measure ∼ 1167 kinematic members of Serpens, few of which were previously identified, to evaluate the star formation history of the complex. The optical members of Serpens are concentrated in three distinct groups located at 380–480 pc; the densest clusters are still highly obscured by optically-thick dust and have few optical members. The total population of young stars and protostars in Serpens is at least 2000 stars, including past surveys that were most sensitive to protostars and disks, and may be far higher. Distances to dark clouds measured from deficits in star counts are consistent with the distances to the optical star clusters. The Serpens Molecular Cloud is seen in the foreground of the Aquila Rift, dark clouds located at 600–700 pc, and behind patchy extinction, here called the Serpens Cirrus, located at ∼ 250 pc. Based on the lack of a distributed population of older stars, the star formation rate throughout the Serpens Molecular Cloud increased by at least a factor of 20 within the past ∼ 5 Myr. The optically bright stars in Serpens Northeast are visible because their natal molecular cloud has been eroded and not because they were flung outwards from a central factory of star formation. The separation between subclusters of 20–100 pc and the absence of an older population leads to speculation that an external forcing was needed to trigger the active star formationNational Science Foundation of ChinaESO - European Southern ObservatoryNational Research Council CanadaNatural Sciences and Engineering Research Council of Canada (NSERC)National Natural Science Foundation of Chin

Isospin influences on particle emission and critical phenomenon in nuclear dissociation

Features of particle emission and critical point behavior are investigated as functions of the isospin of disassembling sources and temperature at a moderate freeze-out density for medium-size Xe isotopes in the framework of isospin dependent lattice gas model. Multiplicities of emitted light particles, isotopic and isobaric ratios of light particles show the strong dependence on the isospin of the dissociation source, but double ratios of light isotope pairs and the critical temperature determined by the extreme values of some critical observables are insensitive to the isospin of the systems. Values of the power law parameter of cluster mass distribution, mean multiplicity of intermediate mass fragments ($IMF$), information entropy ($H$) and Campi's second moment ($S_2$) also show a minor dependence on the isospin of Xe isotopes at the critical point. In addition, the slopes of the average multiplicites of the neutrons ($N_n$), protons ($N_p$), charged particles ($N_{CP}$), and IMFs ($N_{imf}$), slopes of the largest fragment mass number ($A_{max}$), and the excitation energy per nucleon of the disassembling source ($E^*/A$) to temperature are investigated as well as variances of the distributions of $N_n$, $N_p$, $N_{CP}$, $N_{IMF}$, $A_{max}$ and $E^*/A$. It is found that they can be taken as additional judgements to the critical phenomena.Comment: 9 Pages, 8 figure

Mortality in the UK STRIDER trial of sildenafil therapy for the treatment of severe early-onset fetal growth restriction.

Severe early-onset fetal growth restriction (FGR) is an untreatable condition associated with significant mortality and morbidity for the fetus and neonate. There has been growing interest in novel therapies such as nitic oxide donors/promotors to improve placental function and outcomes for these high-risk pregnancies. The recently published STRIDER UK trial was designed to test the effectiveness of sildenafil (25mg three times a day) versus placebo at prolonging gestation in severe early-onset

Wolbachia and DNA barcoding insects: patterns, potential and problems

Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcoding, assessed their impact upon the insect sequence divergence and identification accuracy, and considered the variation present in Wolbachia COI. Using both standard PCR assays (Wolbachia surface coding protein – wsp), and bacterial COI fragments we found evidence of Wolbachia in insect total genomic extracts created for DNA barcoding library construction. When >2 million insect COI trace files were examined on the Barcode of Life Datasystem (BOLD) Wolbachia COI was present in 0.16% of the cases. It is possible to generate Wolbachia COI using standard insect primers; however, that amplicon was never confused with the COI of the host. Wolbachia alleles recovered were predominantly Supergroup A and were broadly distributed geographically and phylogenetically. We conclude that the presence of the Wolbachia DNA in total genomic extracts made from insects is unlikely to compromise the accuracy of the DNA barcode library; in fact, the ability to query this DNA library (the database and the extracts) for endosymbionts is one of the ancillary benefits of such a large scale endeavor – for which we provide several examples. It is our conclusion that regular assays for Wolbachia presence and type can, and should, be adopted by large scale insect barcoding initiatives. While COI is one of the five multi-locus sequence typing (MLST) genes used for categorizing Wolbachia, there is limited overlap with the eukaryotic DNA barcode region

Kinship dynamics: patterns and consequences of changes in local relatedness

This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this recordMounting evidence suggests that patterns of local relatedness can change over time in predictable ways, a process termed kinship dynamics. Kinship dynamics may occur at the level of the population or social group, where the mean relatedness across all members of the population or group changes over time, or at the level of the individual where an individual’s relatedness to its local group changes with age. Kinship dynamics are likely to have fundamental consequences for the evolution of social behaviour and life history because they alter the inclusive fitness payoffs to actions taken at different points in time. For instance, growing evidence suggests that individual kinship dynamics have shaped the evolution of menopause and age-specific patterns of helping and harming. To date, however, the consequences of kinship dynamics for social evolution have not been widely explored. Here we review the patterns of kinship dynamics that can occur in natural populations and highlight how taking a kinship dynamics approach has yielded new insights into behaviour and life history evolution. We discuss areas where analysing kinship dynamics could provide new insight into social evolution and we outline some of the challenges in predicting and quantifying kinship dynamics in natural populations.Natural Environment Research Council (NERC)Leverhulme Trus

Empathy, engagement, entrainment: the interaction dynamics of aesthetic experience

A recent version of the view that aesthetic experience is based in empathy as inner imitation explains aesthetic experience as the automatic simulation of actions, emotions, and bodily sensations depicted in an artwork by motor neurons in the brain. Criticizing the simulation theory for committing to an erroneous concept of empathy and failing to distinguish regular from aesthetic experiences of art, I advance an alternative, dynamic approach and claim that aesthetic experience is enacted and skillful, based in the recognition of others’ experiences as distinct from one’s own. In combining insights from mainly psychology, phenomenology, and cognitive science, the dynamic approach aims to explain the emergence of aesthetic experience in terms of the reciprocal interaction between viewer and artwork. I argue that aesthetic experience emerges by participatory sense-making and revolves around movement as a means for creating meaning. While entrainment merely plays a preparatory part in this, aesthetic engagement constitutes the phenomenological side of coupling to an artwork and provides the context for exploration, and eventually for moving, seeing, and feeling with art. I submit that aesthetic experience emerges from bodily and emotional engagement with works of art via the complementary processes of the perception–action and motion–emotion loops. The former involves the embodied visual exploration of an artwork in physical space, and progressively structures and organizes visual experience by way of perceptual feedback from body movements made in response to the artwork. The latter concerns the movement qualities and shapes of implicit and explicit bodily responses to an artwork that cue emotion and thereby modulate over-all affect and attitude. The two processes cause the viewer to bodily and emotionally move with and be moved by individual works of art, and consequently to recognize another psychological orientation than her own, which explains how art can cause feelings of insight or awe and disclose aspects of life that are unfamiliar or novel to the viewer

Tailoring mathematical models to stem-cell derived cardiomyocyte lines can improve predictions of drug-induced changes to their electrophysiology

Human induced pluripotent stem cell derived cardiomyocytes (iPSC-CMs) have applications in disease modeling, cell therapy, drug screening and personalized medicine. Computational models can be used to interpret experimental findings in iPSC-CMs, provide mechanistic insights, and translate these findings to adult cardiomyocyte (CM) electrophysiology. However, different cell lines display different expression of ion channels, pumps and receptors, and show differences in electrophysiology. In this exploratory study, we use a mathematical model based on iPSC-CMs from Cellular Dynamic International (CDI, iCell), and compare its predictions to novel experimental recordings made with the Axiogenesis Cor.4U line. We show that tailoring this model to the specific cell line, even using limited data and a relatively simple approach, leads to improved predictions of baseline behavior and response to drugs. This demonstrates the need and the feasibility to tailor models to individual cell lines, although a more refined approach will be needed to characterize individual currents, address differences in ion current kinetics, and further improve these results