Hierarchical Cosmic Shear Power Spectrum Inference

We develop a Bayesian hierarchical modelling approach for cosmic shear power spectrum inference, jointly sampling from the posterior distribution of the cosmic shear field and its (tomographic) power spectra. Inference of the shear power spectrum is a powerful intermediate product for a cosmic shear analysis, since it requires very few model assumptions and can be used to perform inference on a wide range of cosmological models \emph{a posteriori} without loss of information. We show that joint posterior for the shear map and power spectrum can be sampled effectively by Gibbs sampling, iteratively drawing samples from the map and power spectrum, each conditional on the other. This approach neatly circumvents difficulties associated with complicated survey geometry and masks that plague frequentist power spectrum estimators, since the power spectrum inference provides prior information about the field in masked regions at every sampling step. We demonstrate this approach for inference of tomographic shear $E$-mode, $B$-mode and $EB$-cross power spectra from a simulated galaxy shear catalogue with a number of important features; galaxies distributed on the sky and in redshift with photometric redshift uncertainties, realistic random ellipticity noise for every galaxy and a complicated survey mask. The obtained posterior distributions for the tomographic power spectrum coefficients recover the underlying simulated power spectra for both $E$- and $B$-modes.Comment: 16 pages, 8 figures, accepted by MNRA

Manned Versus Unmanned Aircraft Accidents, Including Causation and Rates

Many consider aircraft reliability a primary deterrent to the further integration of unmanned aircraft into civil airspace. Discussions of unmanned aircraft reliability often include comparisons of accident rates of medium and large unmanned aircraft (like the MQ-1 Predator and MQ-9 Reaper) to those of manned aircraft. These comparisons, however, often consider a recent period only but do not consider platform maturity. While this approach is valid—and worthy of discussion—it does not present a complete picture of the unmanned aircraft safety record. This paper employs a chi-square goodness-of-fit approach to compare the progression of the U.S. Air Force MQ-9 mishap rate to that of six manned aircraft flown by the same service. The analysis found that the MQ-9 did not have a significantly different Class A mishap rate progression from the comparison aircraft. The only exception was the F-16, which had a considerably higher rate. In addition, to better understand mishap causation, a comparison of manned to unmanned aircraft mishap causal factors was conducted, primarily relying on journal articles that use the Human Factors and Classification System (HFACS) taxonomy. The analysis found that, like manned aircraft, crew errors contributed to a significant portion of unmanned aircraft accidents, and further, that skill-based errors were often the type of the crew error. The studies also indicated that increasing autonomous control, Human Machine Interface (HMI) design, and crew training will continue to play a significant role in unmanned aircraft mishap causation. Two case studies were also analyzed to highlight differences in manned and unmanned aircraft accident causation

Exercise for acute respiratory infections

No abstract available

What's the matter with realism?

International relations, as an academic discipline, is not known for its strength in the area of theory. It has no immediate equivalent to the rich contrasts of perspective generated in sociology by the legacy of Max Weber, Marx and Durkheim—a lack so felt that Martin Wight once wrote a paper called ‘Why is there no International Theory?’ His own answer was, in part, that there is nothing further to theorize after the discovery of the repetitive mechanisms of the balance of power. This was a sad conclusion for such an acute and creative mind to reach. But it does illustrate a central feature of IR theory. For the balance of power, it can be argued, is the limit of any Realist theory of international relations. And Wight's conclusion was perhaps more an index of the dominance of a Realist orthodoxy than a relection of the inherent properties of ‘the international’

What's the matter with realism?

International relations, as an academic discipline, is not known for its strength in the area of theory. It has no immediate equivalent to the rich contrasts of perspective generated in sociology by the legacy of Max Weber, Marx and Durkheim—a lack so felt that Martin Wight once wrote a paper called ‘Why is there no International Theory?’ His own answer was, in part, that there is nothing further to theorize after the discovery of the repetitive mechanisms of the balance of power. This was a sad conclusion for such an acute and creative mind to reach. But it does illustrate a central feature of IR theory. For the balance of power, it can be argued, is the limit of any Realist theory of international relations. And Wight's conclusion was perhaps more an index of the dominance of a Realist orthodoxy than a relection of the inherent properties of ‘the international’

Toxic Byproduct Formation during Electrochemical Treatment of Latrine Wastewater

Electrochemical systems are an attractive option for onsite latrine wastewater treatment due to their high efficiency and small footprint. While concerns remain over formation of toxic byproducts during treatment, rigorous studies examining byproduct formation are lacking. Experiments treating authentic latrine wastewater over variable treatment times, current densities, chloride concentrations, and anode materials were conducted to characterize byproducts and identify conditions that minimize their formation. Production of inorganic byproducts (chlorate and perchlorate) and indicator organic byproducts (haloacetic acids and trihalomethanes) during electrolysis dramatically exceeded recommendations for drinking water after one treatment cycle (∼10–30 000 times), raising concerns for contamination of downstream water supplies. Stopping the reaction after ammonium was removed (i.e., the chlorination breakpoint) was a promising method to minimize byproduct formation without compromising disinfection and nutrient removal. Though treatment was accelerated at increased chloride concentrations and current densities, byproduct concentrations remained similar near the breakpoint. On TiO_2/IrO_2 anodes, haloacetic acids (up to ∼50 μM) and chlorate (up to ∼2 μM) were of most concern. Although boron-doped diamond anodes mineralized haloacetic acids after formation, high production rates of chlorate and perchlorate (up to ∼4 and 25 μM) made them inferior to TiO_2/IrO_2 anodes in terms of toxic byproduct formation. Organic byproduct formation was similar during chemical chlorination and electrolysis of wastewater, suggesting that organic byproducts are formed by similar pathways in both cases (i.e., reactions with chloramines and free chlorine)

THE END OF THE AMERICAN WAY OF WAR & THE PATH FOR THE UNITED STATES TO RECLAIM INFLUENCE IN THE INDO-PACIFIC

In the past two decades the Chinese Communist Party (CCP) has developed and implemented a strategy to nullify the United States’ military influence in the Indo-Pacific region. By establishing a network of Anti-Access/Area Denial (A2/AD) systems in the South China Sea, China has effectively neutralized the United States’ most powerful and technologically-laden platforms. In doing so, they have degraded America’s ability to project power in the air and at sea. As a result, the credibility of American conventional deterrence is in question in the region. The U.S. Navy and Marine Corps have designed a means of countering China’s active defense in the South China Sea—Expeditionary Advanced Base Operations (EABO). However, the efficacy of EABO as a deterrent is closely linked to security cooperation relationships with partner nations throughout the Indo-Pacific. This study begins by examining the nature of the threat in the South China Sea, its effect on current U.S. strategy, and outlines the requirements to facilitate EABO. It then proceeds to evaluate the state of U.S. security cooperation relationships of eight critical countries in the region, which are necessary to effectively utilize EABO as means of deterrence against Chinese aggression in the South China Sea. The results of the study suggest that while the United States has varying degrees of security cooperation relationships, the vast majority fall short of what is necessary to implement EABO as a deterrent. The study concludes with policy suggestions and strategic considerations for the future

Investigating trophic ecology and dietary niche overlap among morphs of Lake Trout in Lake Superior

Four morphs of Lake Trout (Salvelinus namaycush, Walbaum 1792) have been identified in Lake Superior: leans, siscowets, humpers, and redfins. In this comprehensive study, the trophic ecology of Lake Trout morphs were characterized using stomach content, fatty acid, and stable isotope data. Stomach content results indicated a predominately piscivorous diet for leans, siscowets, and redfins, whereas humper diets were comprised of 50% fish and 50% Mysis by mass. Humper and siscowets were most similar in their dietary fatty acid profiles, whereas redfins had the most distinct dietary fatty acid profile. Results from stable isotope analysis revealed some among-morph differences along a pelagic-profundal consumption gradient (34S), but there were no significant differences in trophic position (15N) or basal carbon sources among morphs (13C). Using the recently developed nicheROVER software package, 4-dimensional trophic niches for each morph were quantified using stable isotope ratios (δ13C, δ15N, and δ34S) and fatty acid profiles (30 dietary fatty acids, condensed to one axis). Humpers had the largest 4-dimensional niche regions of all four morphs, and redfins had the smallest. Pairwise probability of overlap among morphs in these four-dimensional niche regions was determined to be < 50% in most cases. Overall, stomach content results indicate that humpers diets were more planktivorous than the other morphs, consistent with previous research. Results of the niche overlap analysis suggests some degree of generalist feeding for all morphs. Better characterization of seasonal variation in diet using tracers that reflect more recent feeding (e.g., fatty acids, stomach contents, and/or stable isotope analyses performed on tissues that turnover more quickly than muscle) are needed to further elucidate among-morph differences and similarities in diet and trophic ecology

Rats on the Rocks: Does Intermittent Stress Exposure During Adolescence Lead to Increases in Alcohol Drinking?

Finalist for Awar