Thermal entanglement and efficiency of the quantum Otto cycle for the su(1,1) Tavis-Cummings system

The influence of the dynamical Stark shift on the thermal entanglement and the efficiency of the quantum Otto cycle is studied for the su(1,1) Tavis-Cummings system. It is shown that the degree of the thermal entanglement becomes larger as the dynamical Stark shift increases. In contrast, the efficiency of the Otto cycle is degraded with an increase of the values of dynamical Stark shift. Expressions for the efficiency coefficient are derived. Using those expressions we identify the maximal efficiency of the quantum Otto cycle from the experimentally measured values of the dynamical Stark shiftComment: to appear in J.Phys.

Radio Observations of GRB Host Galaxies

We present 5.5 and 9.0 GHz observations of a sample of seventeen GRB host galaxies at 0.5<z<1.4, using the radio continuum to explore their star formation properties in the context of the small but growing sample of galaxies with similar observations. Four sources are detected, one of those (GRB 100418A) likely due to lingering afterglow emission. We suggest that the previously-reported radio afterglow of GRB 100621A may instead be due to host galaxy flux. We see no strong evidence for redshift evolution in the typical star formation rate of GRB hosts, but note that the fraction of `dark' bursts with detections is higher than would be expected given constraints on the more typical long GRB population. We also determine the average radio-derived star formation rates of core collapse supernovae at comparable redshift, and show that these are still well below the limits obtained for GRB hosts, and show evidence for a rise in typical star formation rate with redshift in supernova hosts.Comment: 15 pages, MNRAS accepte

A New Population of Ultra-long Duration Gamma-Ray Bursts

We present comprehensive multiwavelength observations of three gamma-ray bursts (GRBs) with durations of several thousand seconds. We demonstrate that these events are extragalactic transients; in particular, we resolve the long-standing conundrum of the distance of GRB 101225A (the "Christmas-day burst"), finding it to have a redshift z = 0.847 and showing that two apparently similar events (GRB 111209A and GRB 121027A) lie at z = 0.677 and z = 1.773, respectively. The systems show extremely unusual X-ray and optical light curves, very different from classical GRBs, with long-lasting, highly variable X-ray emission and optical light curves that exhibit little correlation with the behavior seen in the X-ray. Their host galaxies are faint, compact, and highly star-forming dwarf galaxies, typical of "blue compact galaxies." We propose that these bursts are the prototypes of a hitherto largely unrecognized population of ultra-long GRBs, which while observationally difficult to detect may be astrophysically relatively common. The long durations may naturally be explained by the engine-driven explosions of stars of much larger radii than normally considered for GRB progenitors, which are thought to have compact Wolf-Rayet progenitor stars. However, we cannot unambiguously identify supernova signatures within their light curves or spectra. We also consider the alternative possibility that they arise from the tidal disruption of stars by massive black holes and conclude that the associated timescales are only consistent with the disruption of compact stars (e.g., white dwarfs) by black holes of relatively low mass (<10^5 M_☉)

Economics analysis of mitigation strategies for FMD introduction in highly concentrated animal feeding regions

Outbreaks of infectious animal diseases can lead to substantial losses as evidenced by 2003 US BSE (Bovine Spongiform Encephalopathy) event with consequent loss of export markets, and the 2001 UK FMD (Foot and Mouth Disease) outbreak that has cost estimates in the billions. In this paper we present a linked epidemiologic-economic modeling framework which is used to investigate several FMD mitigation strategies under the context of an FMD outbreak in a concentrated cattle feeding region in the US. In this study we extend the literature by investigating the economic effectiveness of some previously unaddressed strategies including early detection, enhanced vaccine availability, and enhanced surveillance under various combinations of slaughter, surveillance, and vaccination. We also consider different disease introduction points at a large feedlot, a backgrounder feedlot, a large grazing herd, and a backyard herd all in the Texas High Plains. In terms of disease mitigation strategies we evaluate the economic effectiveness of: 1. Speeding up initial detection by one week from day 14 to day 7 after initial infection; 2. Speeding up vaccine availability from one week post disease detection to the day of disease detection; 3.Doubling post event surveillance intensity. To examine the economic implications of these strategies we use a two component stochastic framework. The first component is the epidemiologic model that simulates the spread of FMD as affected by control policies and introduction scenarios. The second component is an economics module, which calculates an estimate of cattle industry losses plus the costs of implementing disease control. The results show that early detection of the disease is the most effective mechanism for minimizing the costs of outbreak. Under some circumstances enhanced surveillance also proved to be an effective strategy.Livestock Production/Industries,

Can constitutions improve democracy? Sometimes, but not always

Does adopting a constitution lead to better democracy? Not necessarily, write Todd A. Eisenstadt, A Carl LeVan, and Tofigh Maboudi, who studied 138 constitutions from a 37 year-period. They find that in many countries, the constitution-making processes did not incorporate broad public consultation, meaning that the drafters were often able to grab power by codifying benefits for themselves and for their supporters

Constitutionalism and Democracy Dataset, Version 1.0

The main objective of the CDD is to quantify the process of constitution-making since 1974. This is the first public release of any data on the process of constitution-making. This release includes data on 144 national constitutions promulgated in 119 countries from 1974 to 2014. The unit of analysis in the data is national constitutions. The data in this release includes only “new” constitutions and does not include suspended, re-installed, amended, or interim constitutions. In this release, only countries with a population larger than 500,000 are included. The authors intend to update the data by including all countries, expanding the time frame, and adding new variables which record the process of constitution-making