Measuring the Angular Momentum Distribution in Core-Collapse Supernova Progenitors with Gravitational Waves

The late collapse, core bounce, and the early postbounce phase of rotating core collapse leads to a characteristic gravitational wave (GW) signal. The precise shape of the signal is governed by the interplay of gravity, rotation, nuclear equation of state (EOS), and electron capture during collapse. We explore the dependence of the signal on total angular momentum and its distribution in the progenitor core by means of a large set of axisymmetric general-relativistic core collapse simulations in which we vary the initial angular momentum distribution in the core. Our simulations include a microphysical finite-temperature EOS, an approximate electron capture treatment during collapse, and a neutrino leakage scheme for the postbounce evolution. We find that the precise distribution of angular momentum is relevant only for very rapidly rotating cores with T/|W|>~8% at bounce. We construct a numerical template bank from our baseline set of simulations, and carry out additional simulations to generate trial waveforms for injection into simulated advanced LIGO noise at a fiducial galactic distance of 10 kpc. Using matched filtering, we show that for an optimally-oriented source and Gaussian noise, advanced Advanced LIGO could measure the total angular momentum to within ~20%, for rapidly rotating cores. For most waveforms, the nearest known degree of precollapse differential rotation is correctly inferred by both our matched filtering analysis and an alternative Bayesian model selection approach. We test our results for robustness against systematic uncertainties by injecting waveforms from simulations using a different EOS and and variations in the electron fraction in the inner core. The results of these tests show that these uncertainties significantly reduce the accuracy with which the total angular momentum and its precollapse distribution can be inferred from observations.Comment: 22 pages, 16 figure

Why We Read Wikipedia

Wikipedia is one of the most popular sites on the Web, with millions of users relying on it to satisfy a broad range of information needs every day. Although it is crucial to understand what exactly these needs are in order to be able to meet them, little is currently known about why users visit Wikipedia. The goal of this paper is to fill this gap by combining a survey of Wikipedia readers with a log-based analysis of user activity. Based on an initial series of user surveys, we build a taxonomy of Wikipedia use cases along several dimensions, capturing users' motivations to visit Wikipedia, the depth of knowledge they are seeking, and their knowledge of the topic of interest prior to visiting Wikipedia. Then, we quantify the prevalence of these use cases via a large-scale user survey conducted on live Wikipedia with almost 30,000 responses. Our analyses highlight the variety of factors driving users to Wikipedia, such as current events, media coverage of a topic, personal curiosity, work or school assignments, or boredom. Finally, we match survey responses to the respondents' digital traces in Wikipedia's server logs, enabling the discovery of behavioral patterns associated with specific use cases. For instance, we observe long and fast-paced page sequences across topics for users who are bored or exploring randomly, whereas those using Wikipedia for work or school spend more time on individual articles focused on topics such as science. Our findings advance our understanding of reader motivations and behavior on Wikipedia and can have implications for developers aiming to improve Wikipedia's user experience, editors striving to cater to their readers' needs, third-party services (such as search engines) providing access to Wikipedia content, and researchers aiming to build tools such as recommendation engines.Comment: Published in WWW'17; v2 fixes caption of Table

E-learning and health inequality aversion : A questionnaire experiment

In principle, questionnaire data on public views about hypothetical trade-offs between improving total health and reducing health inequality can provide useful normative health inequality aversion parameter benchmarks for policymakers faced with real trade-offs of this kind. However, trade-off questions can be hard to understand, and one standard type of question finds that a high proportion of respondents-sometimes a majority-appear to give exclusive priority to reducing health inequality. We developed and tested two e-learning interventions designed to help respondents understand this question more completely. The interventions were a video animation, exposing respondents to rival points of view, and a spreadsheet-based questionnaire that provided feedback on implied trade-offs. We found large effects of both interventions in reducing the proportion of respondents giving exclusive priority to reducing health inequality, though the median responses still implied a high degree of health inequality aversion and-unlike the video-the spreadsheet-based intervention introduced a substantial new minority of non-egalitarian responses. E-learning may introduce as well as avoid biases but merits further research and may be useful in other questionnaire studies involving trade-offs between conflicting values

Understanding the diffusion of public bikesharing systems: evidence from Europe and North America

Since the mid-2000s, public bikesharing (also known as “bike hire”) has developed and spread into a new form of mobility in cities across the globe. This paper presents an analysis of the recent increase in the number of public bikesharing systems. Bikesharing is the shared use of a bicycle fleet, which is accessible to the public and serves as a form of public transportation. The initial system designs were pioneered in Europe and, after a series of technological innovations, appear to have matured into a system experiencing widespread adoption. There are also signs that the policy of public bikesharing systems is transferable and is being adopted in other contexts outside Europe. In public policy, the technologies that are transferred can be policies, technologies, ideals or systems. This paper seeks to describe the nature of these systems, how they have spread in time and space, how they have matured in different contexts, and why they have been adopted. Researchers provide an analysis from Europe and North America. The analysis draws on published data sources, a survey of 19 systems, and interviews with 12 decision-makers in Europe and 14 decision-makers in North America. The data are examined through the lens of diffusion theory, which allows for comparison of the adoption process in different contexts. A mixture of quantitative and qualitative analyses is used to explore the reasons for adoption decisions in different cities. The paper concludes that Europe is still in a major adoption process with new systems emerging and growth in some existing systems, although some geographic areas have adopted alternative solutions. Private sector operators have also been important entrepreneurs in a European context, which has accelerated the uptake of these systems. In North America, the adoption process is at an earlier stage and is gaining momentum, but signs also suggest the growing importance of entrepreneurs in North America with respect to technology and business models. There is evidence to suggest that the policy adoption processes have been inspired by successful systems in Paris, Lyon, Montreal, and Washington, DC, for instance, and that diffusion theory could be useful in understanding public bikesharing policy adoption in a global context

Mycobacterium tuberculosis antigen 85B and ESAT-6 expressed as a recombinant fusion protein in Mycobacterium smegmatis elicits cell-mediated immune response in a murine vaccination model

This is the post-print version of the final paper published in Molecular Immunology. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2012 Elsevier B.V.In this study, we investigated the potential molecular and immunological differences of a recombinant fusion protein (Hybrid-1), comprising of the immunodominant antigens Ag85B and ESAT-6 from Mycobacterium tuberculosis, derived from two different expression systems, namely Mycobacterium smegmatis and Escherichia coli. The fusion protein was successfully expressed and purified from both bacterial hosts and analyzed for any host-dependent post-translational modifications that might affect the immunogenicity of the protein. We investigated the immunogenicity of Hybrid-1 expressed in the two host species in a murine vaccination model, together with a reference standard Hybrid-1 (expressed in E. coli) from the Statens Serum Institut. No evidence of any post-translation modification was found in the M. smegmatis-derived Hybrid-1 fusion protein, nor were there any significant differences in the T-cell responses obtained to the three antigens analyzed. In conclusion, the Hybrid-1 fusion protein was successfully expressed in a homologous expression system using M. smegmatis and this system is worth considering as a primary source for vaccination trials, as it provided protein of excellent yield, stability and free from lipopolysaccharide.European TB-VAC consortium and Brunel University

Fluid and Diffusion Limits for Bike Sharing Systems

Bike sharing systems have rapidly developed around the world, and they are served as a promising strategy to improve urban traffic congestion and to decrease polluting gas emissions. So far performance analysis of bike sharing systems always exists many difficulties and challenges under some more general factors. In this paper, a more general large-scale bike sharing system is discussed by means of heavy traffic approximation of multiclass closed queueing networks with non-exponential factors. Based on this, the fluid scaled equations and the diffusion scaled equations are established by means of the numbers of bikes both at the stations and on the roads, respectively. Furthermore, the scaling processes for the numbers of bikes both at the stations and on the roads are proved to converge in distribution to a semimartingale reflecting Brownian motion (SRBM) in a $N^{2}$-dimensional box, and also the fluid and diffusion limit theorems are obtained. Furthermore, performance analysis of the bike sharing system is provided. Thus the results and methodology of this paper provide new highlight in the study of more general large-scale bike sharing systems.Comment: 34 pages, 1 figure

Protocol for a national, mixed-methods knowledge, attitudes and practices survey on non-communicable diseases

Background Mongolia is undergoing rapid epidemiological transition with increasing urbanisation and economic development. The lifestyle and health of Mongolians are changing as a result, shown by the 2005 and 2009 STEPS surveys (World Health Organization's STEPwise Approach to Chronic Disease Risk Factor Surveillance) that described a growing burden of Non-Communicable Diseases and injuries (NCDs). This study aimed to assess, describe and explore the knowledge, attitudes and practices of the Mongolian adult population around NCDs in order to better understand the drivers and therefore develop more appropriate solutions to this growing disease burden. In addition, it aimed to provide data for the evaluation of current public health programs and to assist in building effective, evidence-based health policy. Methods/design This national survey consisted of both quantitative and qualitative methods. A quantitative household-based questionnaire was conducted using a nationally representative sample of 3854 rural and urban households. Participants were selected using a multi-stage cluster sampling technique in 42 regions across Mongolia, including rural and urban sites. Permanent residents of sampled households were eligible for recruitment, if aged between 15-64 years. This quantitative arm was then complemented and triangulated with a qualitative component: twelve focus group discussions focusing on diet, exercise and alcohol consumption. Discussions took place in six sites across the country, facilitated by local, trained health workers. These six sites were chosen to reflect major Mongolian cultural and social groups. Discussion KAP surveys are well represented in the literature, but studies that aim to explore the knowledge, attitudes and practices of a population around NCDs remain scarce. This is despite the growing number of national epidemiological surveys, such as STEPS, which aim to quantify the burden of these diseases but do not explore the level of population-based awareness, understanding, risk-perception and possible motivation for change. Therefore this paper will contribute to building a knowledge base of NCD KAP survey methodology for future use in epidemiology and research worldwide

How robust are value judgements of health inequality aversion? Testing for framing and cognitive effects

Background: Empirical studies have found that members of the public are inequality averse and value health gains for disadvantaged groups with poor health many times more highly than gains for better off groups. However, these studies typically use abstract scenarios that involve unrealistically large reductions in health inequality, and face-to-face survey administration. It is not known how robust these findings are to more realistic scenarios or anonymous online survey administration. Methods: This study aimed to test the robustness of questionnaire estimates of inequality aversion by comparing the following: (1) small versus unrealistically large health inequality reductions; (2) population-level versus individual-level descriptions of health inequality reductions; (3) concrete versus abstract intervention scenarios; and (4) online versus face to face mode of administration. Fifty-two members of the public participated in face-to-face discussion groups, while 83 members of the public completed an online survey. Participants were given a questionnaire instrument with different scenario descriptions for eliciting aversion to social inequality in health. Results: The median respondent was inequality averse under all scenarios. Scenarios involving small rather than unrealistically large health gains made little difference in terms of inequality aversion, as did population-level rather than individual-level scenarios. However, the proportion expressing extreme inequality aversion fell 19 percentage points when considering a specific health intervention scenario rather than an abstract scenario, and was 11-21 percentage points lower among online public respondents compared to the discussion group. Conclusions: Our study suggests that both concrete scenarios and online administration reduce the proportion expressing extreme inequality aversion but still yield median responses implying substantial health inequality aversion