Custom Made Versus Ready to Wear Treatments; Behavioral Propensities in Physician's Choices

To customize treatments to individual patients entails costs of coordination and cognition. Thus, providers sometimes choose treatments based on norms for broad classes of patients. We develop behavioral hypotheses explaining when and why doctors customize to the particular patient, and when instead they employ "ready-to-wear" treatments. Our empirical studies examining length of office visits and physician prescribing behavior find evidence of norm-following behavior. Some such behavior, from our studies and from the literature, proves sensible; but other behavior seems far from optimal.

The X-ray eclipse of OY Car resolved with XMM-Newton: X-ray emission from the polar regions of the white dwarf

We present the XMM-Newton X-ray eclipse lightcurve of the dwarf nova OY Car. The eclipse ingress and egress are well resolved for the first time in any dwarf nova placing strong constraints on the size and location of the X-ray emitting region. We find good fits to a simple linear eclipse model, giving ingress/egress durations of 30+/-3 sec. Remarkably this is shorter than the ingress/egress duration of the sharp eclipse in the optical as measured by Wood et al. (1989) and ascribed to the white dwarf (43+/-2 sec). We also find that the X-ray eclipse is narrower than the optical eclipse by 14+/-2 sec, which is precisely the difference required to align the second and third contact points of the X-ray and optical eclipses. We discuss these results and conclude that X-ray emission in OY Car most likely arises from the polar regions of the white dwarf. Our data were originally reported by Ramsay et al (2001), but they did not make a quantitative measurement of eclipse parameters. We have also corrected important timing anomalies present in the data available at that time.Comment: 6 pages, 5 figures; accepted for publication in MNRA

The stratified evolution of a cool star

A low mass star usually experiences stratification and abundance anomalies during its evolution. A 0.95 solar mass star with a metallicity Z = 0.004 is followed from the main-sequence to the Horizontal Branch (HB). On the main-sequence the larger effects of stratification may come from accretion as was suggested in relation to metallicity and planet formation. As it evolves through the giant branch, stratification appears around the hydrogen burning shell. It may create hydrodynamic instabilities and be related to abundance anomalies on the giant branch. After the He flash the star evolves to the HB. If it loses enough mass, it ends up a hot HB star (or in the field an sdB star) with effective temperatures larger than 11000 K. All sdB stars are observed to have an approximately solar iron abundance whatever their original metallicity, implying overabundances by factors of up to 100. So should the 0.95 solar mass star. How its internal hydrodynamic properties on the main sequence may influence its fate on the HB is currently uncertain.Comment: Astronomische Nachrichten - Astronomical Notes (AN) papers presented at the Cool Stars 17 conference 2012 (AN 334, issue 1-2

Galaxy Formation Spanning Cosmic History

Over the past several decades, galaxy formation theory has met with significant successes. In order to test current theories thoroughly we require predictions for as yet unprobed regimes. To this end, we describe a new implementation of the Galform semi-analytic model of galaxy formation. Our motivation is the success of the model described by Bower et al. in explaining many aspects of galaxy formation. Despite this success, the Bower et al. model fails to match some observational constraints and certain aspects of its physical implementation are not as realistic as we would like. The model described in this work includes substantially updated physics, taking into account developments in our understanding over the past decade, and removes certain limiting assumptions made by this (and most other) semi-analytic models. This allows it to be exploited reliably in high-redshift and low mass regimes. Furthermore, we have performed an exhaustive search of model parameter space to find a particular set of model parameters which produce results in good agreement with a wide range of observational data (luminosity functions, galaxy sizes and dynamics, clustering, colours, metal content) over a wide range of redshifts. This model represents a solid basis on which to perform calculations of galaxy formation in as yet unprobed regimes.Comment: MNRAS accepted. Extended version (with additional figures and details of implementation) is available at http://www.galform.or

How should fracking research be funded?

The use of hydraulic fracturing (‘fracking’) to extract oil or gas from shales is a subject of controversy. There are many scientific questions about the risks associated with the technique, and much research remains to be done. ReFINE (Researching Fracking In Europe) is a research consortium led by Newcastle University and Durham University in the UK, focusing on the environmental impacts of shale gas and oil exploitation using fracking methods. The project was established to answer questions raised by members of the public across Europe on the risks of fracking. It aims to inform the debate surrounding fracking by undertaking scientific research, which will be peer-reviewed and openly accessible. This case study discusses the structure of ReFINE and the issues associated with using funding from oil and gas companies to support the research

Sequential Monte Carlo with transformations

This paper examines methodology for performing Bayesian inference sequentially on a sequence of posteriors on spaces of different dimensions. For this, we use sequential Monte Carlo samplers, introducing the innovation of using deterministic transformations to move particles effectively between target distributions with different dimensions. This approach, combined with adaptive methods, yields an extremely flexible and general algorithm for Bayesian model comparison that is suitable for use in applications where the acceptance rate in reversible jump Markov chain Monte Carlo is low. We use this approach on model comparison for mixture models, and for inferring coalescent trees sequentially, as data arrives

The Online Laboratory: Conducting Experiments in a Real Labor Market

Online labor markets have great potential as platforms for conducting experiments, as they provide immediate access to a large and diverse subject pool and allow researchers to conduct randomized controlled trials. We argue that online experiments can be just as valid---both internally and externally---as laboratory and field experiments, while requiring far less money and time to design and to conduct. In this paper, we first describe the benefits of conducting experiments in online labor markets; we then use one such market to replicate three classic experiments and confirm their results. We confirm that subjects (1) reverse decisions in response to how a decision-problem is framed, (2) have pro-social preferences (value payoffs to others positively), and (3) respond to priming by altering their choices. We also conduct a labor supply field experiment in which we confirm that workers have upward sloping labor supply curves. In addition to reporting these results, we discuss the unique threats to validity in an online setting and propose methods for coping with these threats. We also discuss the external validity of results from online domains and explain why online results can have external validity equal to or even better than that of traditional methods, depending on the research question. We conclude with our views on the potential role that online experiments can play within the social sciences, and then recommend software development priorities and best practices

Non-isothermal buckling behavior of viscoplastic shell structures

Described are the mathematical model and solution methodologies for analyzing the structural response of thin, metallic elasto-viscoplastic shell structures under large thermomechanical loads and their non-isothermal buckling behavior. Among the system responses associated with these loads and conditions are snap-through, buckling, thermal buckling, and creep buckling. This geometric and material nonlinearities (of high order) can be anticipated and are considered in the model and the numerical treatment