Universal behavior of quantum Green's functions

We consider a general one-particle Hamiltonian H = - \Delta_r + u(r) defined in a d-dimensional domain. The object of interest is the time-independent Green function G_z(r,r') = . Recently, in one dimension (1D), the Green's function problem was solved explicitly in inverse form, with diagonal elements of Green's function as prescribed variables. The first aim of this paper is to extract from the 1D inverse solution such information about Green's function which cannot be deduced directly from its definition. Among others, this information involves universal, i.e. u(r)-independent, behavior of Green's function close to the domain boundary. The second aim is to extend the inverse formalism to higher dimensions, especially to 3D, and to derive the universal form of Green's function for various shapes of the confining domain boundary.Comment: 46 pages, the shortened version submitted to J. Math. Phy

Oceanographic drivers of population differentiation in Indo-Pacific bottlenose (Tursiops aduncus) and humpback (Sousa spp.) dolphins of the northern Bay of Bengal

The Bay of Bengal is one of the most productive ecosystems in the northern Indian Ocean and it harbours a rich community of cetaceans, including Indo-Pacific bottlenose (Tursiops aduncus) and humpback (Sousa spp.) dolphins. The taxonomy of these genera has been controversial, but within the Indian Ocean both seem to be divided into phylogenetically discrete units that range from the east to the west. Within the Sousa genus, S. plumbea is distributed in the western Indian Ocean while S. chinensis is distributed in the eastern Indian and western Pacific Ocean. T. aduncus has a discontinuous distribution throughout the Indo-Pacific Ocean and two different phylogenetic units are known to exist, one along the eastern African coast and another one in the eastern Indian and west Pacific Ocean. In this study we investigate the phylogeography of Indo-Pacific humpback and bottlenose dolphins in the northern Bay of Bengal. We sequenced the mitochondrial DNA control region for 17 bottlenose and 15 humpback dolphins and compared the results with previously published sequences within each genus. In both cases, we found that Bangladesh dolphins are genetically different from neighbouring populations. While the Bangladesh T. aduncus seem to be more closely related to the African T. aduncus form than the Pacific form, Sousa spp. seem to be more closely related to individuals from Australia. The genetic uniqueness of these populations has important evolutionary implications, due to their isolation, coastal distribution in a geographic cul-de-sac characterized by an extreme infusion, redistribution and recycling of biological productivity, and conservation implications since their survival is threatened in particular by fatal interactions with fisheries. We suggest that the particular and extreme oceanographic conditions found in the Bay of Bengal may be driving speciation in these dolphins and other marine megafauna.info:eu-repo/semantics/publishedVersio

Magnetothermal instability in laser plasmas including hydrodynamic effects

The impact of both density gradients and hydrodynamics on the evolution of the field compressing magnetothermal instability is considered [J. J. Bissell et al., Phys. Rev. Lett. 105, 175001 (2010)]. Hydrodynamic motion is found to have a limited effect on overall growth-rates; however, density gradients are shown to introduce an additional source term corresponding to a generalised description of the field generating thermal instability [D. Tidman and R. Shanny, Phys. Fluids 17, 1207 (1974)]. The field compressing and field generating source terms are contrasted, and the former is found to represent either the primary or sole instability mechanism for a range of conditions, especially those with Hall parameter v > 101. The generalised theory is compared to numerical simulation in the context of a recent nano-second gas-jet experiment [D. H. Froula et al., Phys. Rev. Lett. 98, 135001 (2007)] and shown to be in good agreement: exhibiting peak growth-rates and wavelengths of order 10 ns1 and 50 lm, respectively. The instability’s relevance to other experimental conditions, including those in inertial confinement fusion (I.C.F.) hohlraums, is also discussed

Bose-Einstein condensation in arbitrarily shaped cavities

We discuss the phenomenon of Bose-Einstein condensation of an ideal non-relativistic Bose gas in an arbitrarily shaped cavity. The influence of the finite extension of the cavity on all thermodynamical quantities, especially on the critical temperature of the system, is considered. We use two main methods which are shown to be equivalent. The first deals with the partition function as a sum over energy levels and uses a Mellin-Barnes integral representation to extract an asymptotic formula. The second method converts the sum over the energy levels to an integral with a suitable density of states factor obtained from spectral analysis. The application to some simple cavities is discussed.Comment: 10 pages, LaTeX, to appear in Physical Review

Stability of the Autism Diagnostic Interview—Revised from Pre-School to Elementary School Age in Children with Autism Spectrum Disorders

This study examined the stability of scores on the ADI-R from pre-school to elementary school age in children with autism spectrum disorders (ASD). Participants were 35 children who, at T1, all had a clinical diagnosis of ASD. On initial assessment (mean age 3.5 years; SD 0.6), all met ADI-R algorithm criteria for autism. ADI-R assessments were repeated at follow up (FU; mean age 10.5 years; SD 0.8). Changes in ADI-R total, domain and ADI-R algorithm item scores were assessed. Twentyeight children continued to score above the ADI-R cut-off for autism at FU, although significant decreases in ADI-R domain and item scores were also found. In conclusion, while classification of children according to ADI-R criteria, generally remained stable between pre-school and elementary school age, many children demonstrated significant improvements in symptom severity

Randomized community-level HIV prevention intervention trial for men who drink in South African alcohol-serving venues

South African alcohol-serving establishments (i.e., shebeens) offer unique opportunities to reduce HIV risks among men who drink. Purpose: To test an individual- and a social structural-level HIV prevention intervention for men who drink in shebeens. Methods: Twelve matched pairs of township neighbourhoods were randomized to receive either (i) an HIV prevention intervention (guided by Social Action Theory) to reduce sexual risk and increase risk reduction communication in social networks, or (ii) an attention-matched control intervention that focused on the prevention of relationship violence. At the individual level, the interventions delivered skills building workshops focused on sexual risk reduction. At the social structural level, the intervention aimed to increase conversations about safer sex among men in the shebeens, distributed small media and implemented community educational events. Individual-level outcomes were assessed by following the workshop cohorts for 1 year (N = 984), and community-level outcomes were examined through cross-sectional community surveys conducted for 1 year in the shebeens (N = 9,678). Results: Men in the HIV prevention workshops demonstrated greater condom use, more HIV prevention-oriented conversations and greater perceptions of safer sex norms than men in the comparison workshops. Changes at the community level demonstrated significant differences in condom use, although the pattern was not consistent over time. Conclusions: Multi-level interventions that target men who drink in South African shebeens may help reduce risks for HIV and other sexually transmitted infections.Web of Scienc

Integrating Teaching and Research in Undergraduate Biology Laboratory Education

A course recently designed and implemented at Stanford University applies practical suggestions for creating research-based undergraduate courses that benefit both teaching and research

Genetic evidence of illegal trade in protected whales links Japan with the US and South Korea

We report on genetic identification of ‘whale meat’ purchased in sushi restaurants in Los Angeles, CA (USA) in October 2009 and in Seoul, South Korea in June and September 2009. Phylogenetic analyses of mtDNA cytochrome b sequences confirmed that the products included three species of whale currently killed in the controversial scientific whaling programme of Japan, but which are protected from international trade: the fin, sei and Antarctic minke. The DNA profile of the fin whale sold in Seoul established a match to products purchased previously in Japan in September 2007, confirming unauthorized trade between these two countries. Following species identification, these products were handed over to the appropriate national or local authorities for further investigation. The illegal trade of products from protected species of whales, presumably taken under a national permit for scientific research, is a timely reminder of the need for independent, transparent and robust monitoring of any future whaling

Implementation of the MPC and A Operations Monitoring (MOM) System at IRT-T FSRE Nuclear Power Institute (NPI)

The Material Protection, Control and Accounting (MPC&A) Program has been working since 1994 with nuclear sites in Russia to upgrade the physical protection (PP) and material control and accounting (MC&A) functions at facilities containing weapons usable nuclear material. In early 2001, the MPC&A program initiated the MPC&A Operations Monitoring (MOM) Project to monitor facilities where MPC&A upgrades have been installed to provide increased confidence that personnel are present and vigilant, provide confidence that security procedures are being properly performed and provide additional assurance that nuclear materials have not been stolen. The MOM project began as a pilot project at the Moscow State Engineering Physics Institute (MEPhI) and a MOM system was successfully installed in October 2001. Following the success of the MEPhI pilot project, the MPC&A Program expanded the installation of MOM systems to several other Russian facilities, including the Nuclear Physics Institute (NPI) in Tomsk. The MOM system was made operational at NPI in October 2004. This paper is focused on the experience gained from operation of this system and the objectives of the MOM system. The paper also describes how the MOM system is used at NPI and, in particular, how the data is analyzed. Finally, potential expansion of the MOM system at NPI is described