Universal efficiency at optimal work with Bayesian statistics

If the work per cycle of a quantum heat engine is averaged over an appropriate prior distribution for an external parameter $a$, the work becomes optimal at Curzon-Ahlborn efficiency. More general priors of the form $\Pi(a) \propto 1/a^{\gamma}$ yield optimal work at an efficiency which stays close to CA value, in particular near equilibrium the efficiency scales as one-half of the Carnot value. This feature is analogous to the one recently observed in literature for certain models of finite-time thermodynamics. Further, the use of Bayes' theorem implies that the work estimated with posterior probabilities also bears close analogy with the classical formula. These findings suggest that the notion of prior information can be used to reveal thermodynamic features in quantum systems, thus pointing to a new connection between thermodynamic behavior and the concept of information.Comment: revtex4, 5 pages, abstract changed and presentation improved; results unchanged. New result with Bayes Theorem adde

Development of a laser Doppler system for the detection and monitoring of atmospheric disturbances

A Scanning Laser Doppler Velocimeter System (SLDVS) capable of detecting and monitoring atmospheric disturbances, including wake vortices of landing aircraft and vertical wind profiles in the atmosphere was developed. The SLDVS is a focused, continuous wave, CO2 system that determines the line-of-sight velocities of particles in the focal volume by measuring the Doppler shift created by these particles. At present, the SLDVS is designed to have a range coverage of approximately 2000 ft with a vertical angle coverage of approximately 60 deg. It is also designed to detect Doppler velocities of up to 200 ft/sec with a velocity resolution of approximately 1.8 ft/sec. A complete velocity spectrum is provided by the SLDVS at each point in space at which it is focused. The overall operation and performance of the system and the description of its individual components and data handling capabilities were given

Why bayesian “evidence for H1” in one condition and bayesian “evidence for H0” in another condition does not mean good-enough bayesian evidence for a difference between the conditions

Psychologists are often interested in whether an independent variable has a different effect in condition A than in condition B. To test such a question, one needs to directly compare the effect of that variable in the two conditions (i.e., test the interaction). Yet many researchers tend to stop when they find a significant test in one condition and a nonsignificant test in the other condition, deeming this as sufficient evidence for a difference between the two conditions. In this Tutorial, we aim to raise awareness of this inferential mistake when Bayes factors are used with conventional cutoffs to draw conclusions. For instance, some researchers might falsely conclude that there must be good-enough evidence for the interaction if they find good-enough Bayesian evidence for the alternative hypothesis, H1, in condition A and good-enough Bayesian evidence for the null hypothesis, H0, in condition B. The case study we introduce highlights that ignoring the test of the interaction can lead to unjustified conclusions and demonstrates that the principle that any assertion about the existence of an interaction necessitates the direct comparison of the conditions is as true for Bayesian as it is for frequentist statistics. We provide an R script of the analyses of the case study and a Shiny app that can be used with a 2 × 2 design to develop intuitions on this issue, and we introduce a rule of thumb with which one can estimate the sample size one might need to have a well-powered design

To defeat a maverick: Foreign policy, Barry Goldwater and the 1964 presidential election

This paper examines Cold War influences on early post-World War II presidential elections, Barry M. Goldwater\u27s rise to Republican presidential nominee, and the contribution of foreign policy issues to the Arizonan\u27s defeat in the 1964 presidential election. World War II and the Cold War increased the importance of foreign policy considerations in presidential elections, and from 1948 through 1964, every major party nominee advocated the militant containment of communism. Goldwater was an ardent Cold Warrior, who had developed staunch convictions on domestic and foreign matters. As a senator, his unwavering conservatism cast him as a maverick among other Republicans; however, in 1964 the GOP right wing dominated state and local party machinery and the increasingly popular Arizonan captured the presidential nomination. The margin of Goldwater\u27s overwhelming election defeat was due largely to the public\u27s perception of him as an impulsive radical who would senselessly risk nuclear confrontation in the Cold War. This grossly unfavorable perception was propagated by the senator\u27s numerous Republican and Democratic critics, although Goldwater, himself, bore significant responsibility for the image

Dark matter and dark energy as a effects of Modified Gravity

We explain the effect of dark matter (flat rotation curve) using modified gravitational dynamics. We investigate in this context a low energy limit of generalized general relativity with a nonlinear Lagrangian ${\cal L}\propto R^n$, where $R$ is the (generalized) Ricci scalar and $n$ is parameter estimated from SNIa data. We estimate parameter $\beta$ in modified gravitational potential $V(r) \propto -\frac{1}{r}(1+(\frac{r}{r_c})^{\beta})$. Then we compare value of $\beta$ obtained from SNIa data with $\beta$ parameter evaluated from the best fitted rotation curve. We find $\beta \simeq 0.7$ which becomes in good agreement with an observation of spiral galaxies rotation curve. We also find preferred value of $\Omega_{m,0}$ from the combined analysis of supernovae data and baryon oscillation peak. We argue that although amount of "dark energy" (of non-substantial origin) is consistent with SNIa data and flat curves of spiral galaxies are reproduces in the framework of modified Einstein's equation we still need substantial dark matter. For comparison predictions of the model with predictions of the $\Lambda$CDM concordance model we apply the Akaike and Bayesian information criteria of model selection.Comment: Lectures given at 42nd Karpacz Winter School of Theoretical Physics: Ladek, Poland, 6-11 Feb 200

Media, Celebrity and Philanthropy in China: Doing Good or Doing Nothing?

Based on a statistical analysis of 91 celebrity-endorsed charities in the People’s Republic of China, this paper challenges the popular assumption that celebrity involvement with not-for-profit organizations attracts extensive media coverage. Although China is the largest media market in the world, previous studies of celebrity philanthropy have been conducted almost exclusively in a Western context. Such studies argue passionately for and against the role that celebrities can play in attracting attention to humanitarian causes, focusing on the activities of Western celebrities, corporations and consumers as essential or problematic promoters and providers of aid to people in developing countries. We show that – in China, at least – most of this debate is overblown. Rather than arguing in favour of or against 20 celebrity philanthropy, we provide statistical results suggesting that celebrity endorsement has very little impact on press coverage of charities

Doing good or doing nothing? Celebrity, media and philanthropy in China

© 2015 Southseries Inc., www.thirdworldquarterly.com. Based on a statistical analysis of 91 celebrity-endorsed charities in the People’s Republic of China, this paper challenges the popular assumption that celebrity involvement with not-for-profit organisations attracts extensive media coverage. Although China is the largest media market in the world, previous studies of celebrity philanthropy have been conducted almost exclusively in a Western context. Such studies argue passionately for and against the role that celebrities can play in attracting attention to humanitarian causes, focusing on the activities of Western celebrities, corporations and consumers as essential or problematic promoters and providers of aid to people in developing countries. We show that – in China, at least – most of this debate is overblown. Rather than arguing in favour of or against celebrity philanthropy, we provide statistical results suggesting that celebrity endorsement has very little impact on press coverage of charities

Model selection in cosmology

Model selection aims to determine which theoretical models are most plausible given some data, without necessarily considering preferred values of model parameters. A common model selection question is to ask when new data require introduction of an additional parameter, describing a newly discovered physical effect. We review model selection statistics, then focus on the Bayesian evidence, which implements Bayesian analysis at the level of models rather than parameters. We describe our CosmoNest code, the first computationally efficient implementation of Bayesian model selection in a cosmological context. We apply it to recent WMAP satellite data, examining the need for a perturbation spectral index differing from the scaleinvariant (Harrison–Zel'dovich) case

Laser Doppler technology applied to atmospheric environmental operating problems

Carbon dioxide laser Doppler ground wind data were very favorably compared with data from standard anemometers. As a result of these measurements, two breadboard systems were developed for taking research data: a continuous wave velocimeter and a pulsed Doppler system. The scanning continuous wave laser Doppler velocimeter developed for detecting, tracking and measuring aircraft wake vortices was successfully tested at an airport where it located vortices to an accuracy of 3 meters at a range of 150 meters. The airborne pulsed laser Doppler system was developed to detect and measure clear air turbulence (CAT). This system was tested aboard an aircraft, but jet stream CAT was not encountered. However, low altitude turbulence in cumulus clouds near a mountain range was detected by the system and encountered by the aircraft at the predicted time

Governing China’s Coal Challenge: Changing Public Policy, Debate and Advocacy

© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. This paper examines the nexus of coal–government–society relations in present-day China using a governmentality approach to explore the interactions between policy change, “crisis” management and social action. It outlines the noticeable shift in government rationalities and communication regarding the coal industry in recent years. It then frames this shift within the broader context of government–society relations focusing on public debate regarding the calamitous nature of China’s air pollution and its filtering via the censorship apparatus of the Communist Party-state. Finally, it shows how problems relating to coal extraction and combustion have been taken up at the level of grass-roots protest and philanthropic advocacy. An examination of such activism illustrates the crucial role played by digital media networks in sparking debate on coal-related environmental and health crises, and in pushing an authoritarian government to change national coal and other policies in order to maintain social and political stability