Black hole entropy arising from massless scalar field with Lorentz violation induced by the coupling to Einstein tensor

We have investigated quantum entropy of a static black hole arising from the massless scalar field with Lorentz violation induced by the coupling to Einstein tensor. Our results show that the coupled massless scalar field contributes to the classical Bekenstein-Hawking term in the black hole entropy. The corrected classical Bekenstein-Hawking entropy is not one quarter of the event horizon area of the original background black hole, but of a corresponding effective metric related to the coupling. It means that the classical Bekenstein-Hawking entropy depends not only on the black hole parameter, but also on the coupling which reduces Lorentz violation.Comment: 5 pages, no figure. Accepted by PLB for publicatio

Absorption cross section and Hawking radiation of the electromagnetic field with Weyl corrections

We have investigated the absorption cross section and the Hawking radiation of electromagnetic field with Weyl correction in the background of a four-dimensional Schwarzschild black hole spacetime. Our results show that the properties of the absorption cross section and the Hawking radiation depend not only on the Weyl correction parameter, but also on the parity of the electromagnetic field, which is quite different from those of the usual electromagnetic field without Weyl correction in the four-dimensional spacetime. With increase of Weyl correction parameter, the absorption probability, the absorption cross section, the power emission spectra and the luminosity of Hawking radiation decreases with Weyl correction parameter for the odd-parity electromagnetic field and increases with the event-parity electromagnetic field.Comment: 10 pages, 8 figures. Accepted for publication in Physics Letters

Statistical study of oxygen+ transport from the cusp to the plasmasheet

Using Cluster/CODIF data, we have determined the occurrence frequency of the cusp-source O+ in the magnetotail to determine where and when it is observed. The results show that the probability to observe O+ along the transport path is high even during nonstorm times, although, as expected, the highest probability is found during storm times. In addition to the outflow rate increasing, the transport path itself also changes during storm times, bringing more O+ to the near-earth plasma sheet. Interplanetary magnetic field (IMF) magnitude is the most effective driver for bringing O+ into the near-Earth lobes. It was also found that when IMF By is positive, O+ from the northern cusp/cleft tends to stream towards the dawnside while O+ from the south is observed on the duskside. The transport path for negative IMF By is more symmetric, but shows some evidence for a reversed asymmetry when IMF By is strongly negative. The asymmetry most likely results from the combination of the convection driven by the solar wind and the coupling with the ionosphere. By comparing the normalized distributions of the cusp outflow and the streaming O+ in the magnetotail we show that the increase in the energy of the streaming O+ in the tail lobes is mainly due to the velocity filter effect, not due to acceleration. O+ entering from the lobe into the plasma sheet boundary layer, however, has been accelerated. A case study shows that most of the velocity increase is due to E x B drift, but additional acceleration along the electric field is also found. The probability to observe streaming O + decreases steeply during the declining phase of solar cycle 23 and increases again at the start of solar cycle 24. The reduction factor is much larger in the tail lobes than in the polar cap, due to a change in the transport path

Testing cosmic opacity from SNe Ia and Hubble parameter through three cosmological-model-independent methods

We use the newly published 28 observational Hubble parameter data ($H(z)$) and current largest SNe Ia samples (Union2.1) to test whether the universe is transparent. Three cosmological-model-independent methods (nearby SNe Ia method, interpolation method and smoothing method) are proposed through comparing opacity-free distance modulus from Hubble parameter data and opacity-dependent distance modulus from SNe Ia . Two parameterizations, $\tau(z)=2\epsilon z$ and $\tau(z)=(1+z)^{2\epsilon}-1$ are adopted for the optical depth associated to the cosmic absorption. We find that the results are not sensitive to the methods and parameterizations. Our results support a transparent universe.Comment: 11 pages, 8 figures, 1 table, PLB(in press

Statistical modelling for zoonotic diseases : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Statistics at Massey University, Palmerston North, New Zealand

Copyright is owned by the Author of the thesis. Permission is given for a copy to be downloaded by an individual for the purpose of research and private study only. The thesis may not be reproduced elsewhere without the permission of the Author.Figure 2.1 is published with permission from the American Society for Microbiology.Preventing and controlling zoonoses through the design and implementation of public health policies requires a thorough understanding of epidemiology and transmission pathways. A pathogen may have complex transmission pathways that could be affected by environmental factors, different reservoirs and the food chain. One way to get more insight into a zoonosis is to trace back the putative sources of infection. Approaches to attribute the infection to sources include epidemiological observations and microbial subtyping techniques. In order for source attribution from the pathways to human infection to be delineated, this thesis proposes statistical modelling methods with an integration of demographic variables with multilocus sequence typing data derived from human cases and sources. These models are framed in a Bayesian context, allowing for a flexible use of limited knowledge about the illness to make inferences about the potential sources contributing to human infection. These methods are applied to campylobacteriosis data collected from a surveillance sentinel site in the Manawatu region of New Zealand. A link between genotypes found from sources and human samples is considered in the modelling scheme, assuming genotypes from sources are equal or linked indirectly to that from human cases. Model diagnostics show that the assumption of equal prevalence of genotypes between humans and sources is not tenable, with a few types being potentially more prevalent in humans than in sources, or vice versa. Thus, a model that allows genotypes on humans to differ from those on sources is implemented. In addition, an approximate Bayesian model is also proposed, which essentially cuts the link between human and source genotype distributions when conducting inference. The final inference from these approaches is the probability for human cases attributable to each source, conditional on the extent to which each case resides in a rural compared to urban environment. Results from the effective models suggest that poultry and ruminants are important sources for human campylobacteriosis. The more rural human cases are located, the higher the likelihood of ruminant-sourced cases is. In contrast, cases are more poultry-associated when their locations are more urban. A little rurality effect is noticed for water and other sources due to small sample sizes compared to that from poultry and ruminants. In addition, animal faeces are believed to be the primary cause of water contamination via rainfall or runoff coming from farmland and pasture. When water is treated as a medium in the transmission, instead of an end point, water birds are suggested to be the most likely contributor to water contamination. These findings have implications for public health practice and food safety risk management. A risk management strategy had been carried out in the poultry industry in New Zealand, leading to a marked decrease of urban case rates from a poultry source. However, the findings of this thesis suggest a further step with a focus on rural areas as rural case rates are observed to be relatively higher than urban rates. Further, by exploring the role that water plays in the transmission, it deepens our knowledge of the epidemiology about waterborne campylobacteriosis and highlights the importance of water quality. This opens a potential research direction to study the association of water quality and environmental factors such as higher global temperatures for this disease

Structure fusion based on graph convolutional networks for semi-supervised classification

Suffering from the multi-view data diversity and complexity for semi-supervised classification, most of existing graph convolutional networks focus on the networks architecture construction or the salient graph structure preservation, and ignore the the complete graph structure for semi-supervised classification contribution. To mine the more complete distribution structure from multi-view data with the consideration of the specificity and the commonality, we propose structure fusion based on graph convolutional networks (SF-GCN) for improving the performance of semi-supervised classification. SF-GCN can not only retain the special characteristic of each view data by spectral embedding, but also capture the common style of multi-view data by distance metric between multi-graph structures. Suppose the linear relationship between multi-graph structures, we can construct the optimization function of structure fusion model by balancing the specificity loss and the commonality loss. By solving this function, we can simultaneously obtain the fusion spectral embedding from the multi-view data and the fusion structure as adjacent matrix to input graph convolutional networks for semi-supervised classification. Experiments demonstrate that the performance of SF-GCN outperforms that of the state of the arts on three challenging datasets, which are Cora,Citeseer and Pubmed in citation networks