Narrowing the Gender Pay Gap by Providing Equal Opportunities: The Need for Tenured Female Professors in Higher STEM Institutions in an Effort to Recast Gender Norms

[no abstract

Profile Shapes for Optically Thick X-ray Emission Lines from Stellar Winds

We consider the consequences of appreciable line optical depth for the profile shape of X-ray emission lines formed in stellar winds. The hot gas is thought to arise in distributed wind shocks, and the line formation is predominantly via collisional excitation followed by radiative decay. Such lines are often modelled as optically thin, but the theory has difficulty matching resolved X-ray line profiles. We suggest that for strong lines of abundant metals, newly created photons may undergo resonance scattering, modifying the emergent profile. Using Sobolev theory in a spherically symmetric wind, we show that thick-line resonance scattering leads to emission profiles that still have blueshifted centroids like the thin lines, but which are considerably less asymmetric in appearance. We focus on winds in the constant-expansion domain, and derive an analytic form for the profile shape in the limit of large line and photoabsorptive optical depths. Our theory is applied to published {\it Chandra} observations of the O star $\zeta$ Pup.Comment: ApJ, in pres

Prevalence of head injury and associated disability in prison populations: a systematic review

Objective: This review systematically assesses literature on the prevalence of head injury (HI) and associated disability in adults in prison. Methods: Searches were carried out using electronic databases (PsycINFO, Cochrane Databases, MEDLINE, EMBASE, Web of Science). Reference lists of 2 meta-analyses were checked for relevant articles. Methods were rated for risk of bias. Results: The 10 studies included report a range in prevalence of HI in prisoners from 25% to 86%. Risk of bias was high overall, probably because a range of HI definitions was used, assessments were often not validated, and samples were not or not evidenced to be representative of the prison population. There was an absence of appropriate population controls from which to compare relative risk of HI in different countries. No study reported the prevalence of disability associated with HI. Conclusion: The wide range in prevalence estimates of HI in prisoners is associated with high risk of bias from study design and methods. Persisting disability associated with HI was not reported and as a result the service need for prisoners with HI is unclear. Future studies should indicate that samples are representative of prison populations, use validated tools and internationally accepted definitions of HI, and link prevalence to persisting disability

Within Lake Clustering of High Resolution Satellite Retrievals: A Functional Data and Clustering Approach

No abstract available

Darboux dressing and undressing for the ultradiscrete KdV equation

We solve the direct scattering problem for the ultradiscrete Korteweg de Vries (udKdV) equation, over $\mathbb R$ for any potential with compact (finite) support, by explicitly constructing bound state and non-bound state eigenfunctions. We then show how to reconstruct the potential in the scattering problem at any time, using an ultradiscrete analogue of a Darboux transformation. This is achieved by obtaining data uniquely characterising the soliton content and the `background' from the initial potential by Darboux transformation.Comment: 41 pages, 5 figures // Full, unabridged version, including two appendice

Cooperative Online Learning: Keeping your Neighbors Updated

We study an asynchronous online learning setting with a network of agents. At each time step, some of the agents are activated, requested to make a prediction, and pay the corresponding loss. The loss function is then revealed to these agents and also to their neighbors in the network. Our results characterize how much knowing the network structure affects the regret as a function of the model of agent activations. When activations are stochastic, the optimal regret (up to constant factors) is shown to be of order $\sqrt{\alpha T}$, where $T$ is the horizon and $\alpha$ is the independence number of the network. We prove that the upper bound is achieved even when agents have no information about the network structure. When activations are adversarial the situation changes dramatically: if agents ignore the network structure, a $\Omega(T)$ lower bound on the regret can be proven, showing that learning is impossible. However, when agents can choose to ignore some of their neighbors based on the knowledge of the network structure, we prove a $O(\sqrt{\overline{\chi} T})$ sublinear regret bound, where $\overline{\chi} \ge \alpha$ is the clique-covering number of the network

Evaluating the impact of the rural dimension of specialism

Commissioned by the Specialist Schools and Academies TrustThe rural dimension is intended to offer the opportunity to schools to enhance and extend the curriculum. Its focus is the understanding of environmental issues and the countryside, and it is seen as relevant to all schools, including those in urban areas. The Specialist Schools and Academies Trust (SSAT) wishes to evaluate the extent to which the rural dimension is effective in raising standards. The aim of this study, commissioned by the SSAT, was to ascertain the extent to which the work schools undertake as part of their rural dimension has a demonstrable impact on achievement and attainment - in particular concerning: 1) attainment (pupil performance and school standards); 2) behaviour and attendance (on the part of pupils); 3) engagement (pupil interest and motivation, and raising aspirations among pupils and their families). The approach taken in the study is chiefly an interpretative and illuminative one with the aim of throwing light on how the rural dimension acts as an influence within the school context. Rather than looking for linear cause-and-effect, methodologically it was seen as more helpful to view organisations as complex processes of continual interaction in which any one initiative is the catalyst to multiple interpretations and reactions which generate further initiatives. Qualitative data are particularly helpful in throwing light on these processes. An exploratory case study approach was used, generating both qualitative and quantitative data in order to reflect the complexity of practice and experience in the rural dimension. Six case study schools were selected from rural dimension schools which expressed a wish to participate in the study. Criteria were used to maximise the variation in the sample used, although those with relatively large farms are over-represented. Each of the six case study schools was visited by one or more of the research team. Visits involved interviews, observation and perusal and collection of documentary data (including schools’ websites). This report also includes a selective literature review, highlighting some of the issues concerning research into specialisms and the value of education for sustainable development