641 research outputs found

    Quantum integrable systems in three-dimensional magnetic fields: the Cartesian case

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    In this paper we construct integrable three-dimensional quantum-mechanical systems with magnetic fields, admitting pairs of commuting second-order integrals of motion. The case of Cartesian coordinates is considered. Most of the systems obtained are new and not related to the separation of variables in the corresponding Schr\"odinger equation.Comment: 8 page

    Mosaic expression of Atrx in the mouse central nervous system causes memory deficits

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    The rapid modulation of chromatin organization is thought to play a crucial role in cognitive processes such as memory consolidation. This is supported in part by the dysregulation of many chromatin-remodelling proteins in neurodevelopmental and psychiatric disorders. A key example is ATRX, an X-linked gene commonly mutated in individuals with syndromic and nonsyndromic intellectual disability. The consequences of Atrx inactivation for learning and memory have been difficult to evaluate because of the early lethality of hemizygous-null animals. In this study, we evaluated the outcome of brain-specific Atrx deletion in heterozygous female mice. These mice exhibit a mosaic pattern of ATRX protein expression in the central nervous system attributable to the location of the gene on the X chromosome. Although the hemizygous male mice die soon after birth, heterozygous females survive to adulthood. Body growth is stunted in these animals, and they have low circulating concentrations of insulin growth factor 1. In addition, they are impaired in spatial, contextual fear and novel object recognition memory. Our findings demonstrate that mosaic loss of ATRX expression in the central nervous system leads to endocrine defects and decreased body size and has a negative impact on learning and memory

    Electronic books in public libraries: a feasibility study for developing usage models for web-based and hardware-based electronic books

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    This final report considers the background and implementation of a project that introduced electronic book (ebook) collections to Essex Public Libraries in 2004. The research considered ebook collections available for borrowing on a PDA (HP iPAQ) and collections downloadable on to the borrower’s PDA or PC (OverDrive, ebrary). The project, a partnership consisting of Loughborough University, Essex Public Libraries, and the Co-East Management Team

    4DXpress: a database for cross-species expression pattern comparisons

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    In the major animal model species like mouse, fish or fly, detailed spatial information on gene expression over time can be acquired through whole mount in situ hybridization experiments. In these species, expression patterns of many genes have been studied and data has been integrated into dedicated model organism databases like ZFIN for zebrafish, MEPD for medaka, BDGP for Drosophila or GXD for mouse. However, a central repository that allows users to query and compare gene expression patterns across different species has not yet been established. Therefore, we have integrated expression patterns for zebrafish, Drosophila, medaka and mouse into a central public repository called 4DXpress (expression database in four dimensions). Users can query anatomy ontology-based expression annotations across species and quickly jump from one gene to the orthologues in other species. Genes are linked to public microarray data in ArrayExpress. We have mapped developmental stages between the species to be able to compare developmental time phases. We store the largest collection of gene expression patterns available to date in an individual resource, reflecting 16 505 annotated genes. 4DXpress will be an invaluable tool for developmental as well as for computational biologists interested in gene regulation and evolution. 4DXpress is available at http://ani.embl.de/4DXpress

    Analytical in vitro approach for studying cyto- and genotoxic effects of particulate airborne material

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    In the field of inhalation toxicology, progress in the development of in vitro methods and efficient exposure strategies now offers the implementation of cellular-based systems. These can be used to analyze the hazardous potency of airborne substances like gases, particles, and complex mixtures (combustion products). In addition, the regulatory authorities require the integration of such approaches to reduce or replace animal experiments. Although the animal experiment currently still has to provide the last proof of the toxicological potency and classification of a certain compound, in vitro testing is gaining more and more importance in toxicological considerations. This paper gives a brief characterization of the CULTEX® Radial Flow System exposure device, which allows the exposure of cultivated cells as well as bacteria under reproducible and stable conditions for studying cellular and genotoxic effects after the exposure at the air–liquid or air–agar interface, respectively. A commercial bronchial epithelial cell line (16HBE14o-) as well as Salmonella typhimurium tester strains were exposed to smoke of different research and commercial available cigarettes. A dose-dependent reduction of cell viability was found in the case of 16HBE14o- cells; S. typhimurium responded with a dose-dependent induction of revertants. The promising results recommend the integration of cellular studies in the field of inhalation toxicology and their regulatory acceptance by advancing appropriate validation studies

    Promoting responsibility, shaping behaviour: housing management, mixed communities and the construction of citizenship

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    This article examines housing policies aimed at establishing mixed income communities. Based on stakeholder interviews and case study analysis in England and Scotland, the article pays particular attention to the impact of interventions in housing management. The first part of the article considers the policy context for mixed communities and considers the conceptual basis underlying contemporary housing management through discourses of culture and social control. The second part considers how this agenda has resulted in the adoption of intensive management strategies within mixed communities; illustrated in the development of allocation policies, initiatives designed to tackle anti-social behaviour and proposals to develop sustainable communities. The main argument is given that the concept of mixed communities is based on the premise of social housing failure, citizenship has been defined largely in response to private sector interests. This approach to management has been a contributory factor in the construction of social housing as a form of second-class citizenship
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