A Comprehensive Analysis of Fermi Gamma-Ray Burst Data. IV. Spectral Lag and its Relation to E p Evolution

The spectral evolution and spectral lag behavior of 92 bright pulses from 84 gamma-ray bursts observed by the Fermi Gamma-ray Burst Monitor (GBM) telescope are studied. These pulses can be classified into hard-to-soft pulses (H2S; 64/92), H2S-dominated-tracking pulses (21/92), and other tracking pulses (7/92). We focus on the relationship between spectral evolution and spectral lags of H2S and H2S-dominated-tracking pulses. The main trend of spectral evolution (lag behavior) is estimated with ( ), where E p is the peak photon energy in the radiation spectrum, t + t 0 is the observer time relative to the beginning of pulse −t 0, and is the spectral lag of photons with energy E with respect to the energy band 8–25 keV. For H2S and H2S-dominated-tracking pulses, a weak correlation between and k E is found, where W is the pulse width. We also study the spectral lag behavior with peak time of pulses for 30 well-shaped pulses and estimate the main trend of the spectral lag behavior with . It is found that is correlated with k E . We perform simulations under a phenomenological model of spectral evolution, and find that these correlations are reproduced. We then conclude that spectral lags are closely related to spectral evolution within the pulse. The most natural explanation of these observations is that the emission is from the electrons in the same fluid unit at an emission site moving away from the central engine, as expected in the models invoking magnetic dissipation in a moderately high-σ outflow

A comprehensive analysis of Fermi Gamma-Ray Burst Data: IV. Spectral lag and Its Relation to Ep Evolution

The spectral evolution and spectral lag behavior of 92 bright pulses from 84 gamma-ray bursts (GRBs) observed by the Fermi GBM telescope are studied. These pulses can be classified into hard-to-soft pulses (H2S, 64/92), H2S-dominated-tracking pulses (21/92), and other tracking pulses (7/92). We focus on the relationship between spectral evolution and spectral lags of H2S and H2S-dominated-tracking pulses. %in hard-to-soft pulses (H2S, 64/92) and H2S-dominating-tracking (21/92) pulses. The main trend of spectral evolution (lag behavior) is estimated with $\log E_p\propto k_E\log(t+t_0)$ (${\hat{\tau}} \propto k_{\hat{\tau}}\log E$), where $E_p$ is the peak photon energy in the radiation spectrum, $t+t_0$ is the observer time relative to the beginning of pulse $-t_0$, and ${\hat{\tau}}$ is the spectral lag of photons with energy $E$ with respect to the energy band $8$-$25$ keV. For H2S and H2S-dominated-tracking pulses, a weak correlation between $k_{{\hat{\tau}}}/W$ and $k_E$ is found, where $W$ is the pulse width. We also study the spectral lag behavior with peak time $t_{\rm p_E}$ of pulses for 30 well-shaped pulses and estimate the main trend of the spectral lag behavior with $\log t_{\rm p_E}\propto k_{t_p}\log E$. It is found that $k_{t_p}$ is correlated with $k_E$. We perform simulations under a phenomenological model of spectral evolution, and find that these correlations are reproduced. We then conclude that spectral lags are closely related to spectral evolution within the pulse. The most natural explanation of these observations is that the emission is from the electrons in the same fluid unit at an emission site moving away from the central engine, as expected in the models invoking magnetic dissipation in a moderately-high-$\sigma$ outflow.Comment: 58 pages, 11 figures, 3 tables. ApJ in pres

Efficient market hypothesis and fraud on the market theory: A new perspective for class actions

Following recent judgement of the Supreme Court of US (June 2014), several commentators had declared that “Securities class actions are here to stay” (insidecounsel.com – September 2014, 11). This paper provides a critical perspective on this judgement, which “implicates substantive issues at the intersection of economic theory, financial markets, and securities regulation” (128 Harv. L. Rev. 291 2014-2015, 291), and shows that we must be much more careful. This recent judgement is based on the Fraud on the Market Doctrine, which was introduced in 1973 in order to preserve the class action procedure in securities fraud litigation. The characteristic of the Fraud on the Market Doctrine is to have been structured from one of the most popular financial theory: Efficient Market Hypothesis. In this paper, by analysing the implementation of the Efficient Market Hypothesis in Fraud on the Market Theory, we argue that if the Supreme Court had to take position for a second time about the Fraud on the Market Doctrine it is due to the practical difficulties inherited from Efficient Market Hypothesis and that have raised several problems to the US courts, including the Supreme Court. This issue is illustrated by the definition of Efficient Market Hypothesis lawyers used (“most” vs “all”/”fully”). As this paper shows, if “Securities class actions are here to stay”, the opportunity to open such a class action is strongly reduced in the facts

Contrasting reservoirs for Schistosoma japonicum between marshland and hilly regions in Anhui, China--a two-year longitudinal parasitological survey.

Schistosoma japonicum remains highly endemic in many counties in China and has recently re-emerged, to a large extent, in previously controlled areas. To test the hypothesis that small rodents and less agriculturally important domestic animals such as dogs and cats may play an important role in the transmission and potential re-emergence of this disease, an annual investigation of S. japonicum among humans, domestic animals and rodents, combined with detailed surveys of the snail intermediate host, was performed across 3 marshland villages and 3 hilly villages in Anhui province of China over 2 consecutive years. The highest infection prevalence and intensity observed across all mammals was in rodents in the hilly region; while in the marshland, bovines were suspected as the main reservoirs. However, relatively high infection prevalence levels were also found in dogs and cats in both regions. Such results may have implications for the current human- and bovine-oriented control policy for this medically and veterinarily important disease, particularly within the hilly regions of mainland China

Towards prediction of ordered phases in rechargeable battery chemistry via group–subgroup transformation

Abstract: The electrochemical thermodynamic and kinetic characteristics of rechargeable batteries are critically influenced by the ordering of mobile ions in electrodes or solid electrolytes. However, because of the experimental difficulty of capturing the lighter migration ion coupled with the theoretical limitation of searching for ordered phases in a constrained cell, predicting stable ordered phases involving cell transformations or at extremely dilute concentrations remains challenging. Here, a group-subgroup transformation method based on lattice transformation and Wyckoff-position splitting is employed to predict the ordered ground states. We reproduce the previously reported Li0.75CoO2, Li0.8333CoO2, and Li0.8571CoO2 phases and report a new Li0.875CoO2 ground state. Taking the advantage of Wyckoff-position splitting in reducing the number of configurations, we identify the stablest Li0.0625C6 dilute phase in Li-ion intercalated graphite. We also resolve the Li/La/vacancy ordering in Li3xLa2/3−xTiO3 (0 < x < 0.167), which explains the observed Li-ion diffusion anisotropy. These findings provide important insight towards understanding the rechargeable battery chemistry

Population genetics of Oncomelania hupensis snails, intermediate hosts of Schistosoma japonium, from emerging, re-emerging or established habitats within China

Schistosomiasis remains one of the world’s most significant neglected tropical diseases, second only to malaria in terms of socioeconomic impact. In 2014, China proposed the goal of schistosomiasis japonicum elimination by 2025. However, one major challenge is the widely distributed, and in certain cases potentially increasing, habitats of Oncomelania hupensis, the snail intermediate hosts of S. japonicum. Therefore, an understanding of population genetics of O. hupensis in new or re-emerged habitats, together with that of the established habitats with snail persistence, would be valuable in controlling and predicting the future transmission dynamics of schistosomiasis in China. Using nine microsatellite loci, we conducted population genetic analyses of snails sampled from one habitat where snails were detected for the first time, one (previously eliminated) habitat with re-emerged snails, and one habitat with established snail persistence. Results showed lower diversities, in terms of number of observed alleles per locus (Na), number of effective alleles per locus (NeA), observed (Ho) and expected heterozygosity (He), in snails from new or re-emerged snail habitats than from the habitat with snail persistence. The smallest effective population size was inferred in the re-emerged snail habitat, but the largest was in the new habitat rather than in the habitat with snail persistence. No bottleneck effects were detected in new or re-merged habitats. No or low sub-structure was inferred in new and persistent snail habitats. Snails from the three sites were clearly separated and low gene flow was estimated between sites. We propose that snails at the new habitat may have been introduced through immigration, whereas snails at the re-emerged habitat may be the consequence of those few snails remaining subsequently expanding through reproduction. We discuss our results in terms of their theoretical and applied implications

Altered expression of microRNAs in the myocardium of rats with acute myocardial infarction

<p>Abstract</p> <p>Background</p> <p>MicroRNAs(miRNAs) are important cellular components and their dysfunction is associated with various diseases. Acute myocardial infarction (AMI) is one of the most serious cardiovascular diseases. Although several miRNAs are reported to be associated with AMI, more novel miRNAs are needed to further investigate and improve certainty</p> <p>Methods</p> <p>We applied a well-established acute myocardial infarction rat model and performed miRNAs microarray experiments upon the myocardium tissue of rats with AMI and under sham control. We identified the differentially expressed miRNAs and analyzed the function of miRNA targets, transcription factors, and host genes based on bioinformatics.</p> <p>Results</p> <p>As a result, the levels of expression of seventeen miRNAs significantly deregulated, of which four miRNAs were further validated by qRT-PCR. In addition, we observed that the transcription factors, targets, and host genes of these deregulated miRNAs are enriched in cardiovascular-related functions.</p> <p>Conclusion</p> <p>We found that the miRNAs expression level altered in rats with AMI and differentially expressed miRNAs may be novel biomarkers of AMI.</p