940 research outputs found

    Assessment of the dysexecutive syndrome in schizophrenia

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    Background. Cognitive neuropsychological theories hypothesize a role for frontal lobe executive deficits in the aetiology of schizophrenic symptoms. The study examined the performance of a schizophrenic group on the Behavioural Assessment of the Dysexecutive Syndrome (BADS), a test battery which assesses the 'everyday' difficulties associated with the dysexecutive syndrome. Performance of the schizophrenics was contrasted with that of brain injured and healthy volunteer groups. Methods. Matched groups of 31 schizophrenic patients, 35 patients-with brain injuries and 26 healthy volunteers were administered the BADS. Patients were also given tests of general intelligence and memory. Patients and their relatives/carers also completed a questionnaire rating day-to-day failures of executive functioning. Results. Schizophrenic and brain-injured patients showed impairment on the BADS, compared to healthy controls. There were no significant differences between the two patient groups. Significant impairment was found in a subgroup of 16 schizophrenics who showed otherwise intact general intellectual functioning, suggesting the existence of a specific executive deficit. Among the schizophrenic patient group there was evidence of a dissociation between executive and memory impairments. A significant correlation existed between performance on the BADS and relatives ratings of executive problems for the brain injured group, but not for the schizophrenic group. Conclusions. The BADS is a useful tool for identifying executive deficits in people with a diagnosis of schizophrenia, especially those who are otherwise generally intellectually intact. This is particularly important in the context of rehabilitation and community transition programmes.published_or_final_versio

    Microwave assisted heterogeneous catalysis: effects of varying oxygen concentrations on the oxidative coupling of methane

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    The oxidative coupling of methane was investigated over alumina supported La2O3/CeO2 catalysts under microwave dielectric heating conditions at different oxygen concentrations. It was observed that, at a given temperature using microwave heating, selectivities for both ethane and ethylene were notably higher when oxygen was absent than that in oxygen/methane mixtures. The differences were attributed to the localised heating of microwave radiation resulting in temperature inhomogeneity in the catalyst bed. A simplified model was used to estimate the temperature inhomogeneity; the temperature at the centre of the catalyst bed was 85 °C greater than that at the periphery when the catalyst was heated by microwaves in a gas mixture with an oxygen concentration of 12.5% (v/v), and the temperature difference was estimated to be 168 °C in the absence of oxygen

    A ferroelectric memristor

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    Memristors are continuously tunable resistors that emulate synapses. Conceptualized in the 1970s, they traditionally operate by voltage-induced displacements of matter, but the mechanism remains controversial. Purely electronic memristors have recently emerged based on well-established physical phenomena with albeit modest resistance changes. Here we demonstrate that voltage-controlled domain configurations in ferroelectric tunnel barriers yield memristive behaviour with resistance variations exceeding two orders of magnitude and a 10 ns operation speed. Using models of ferroelectric-domain nucleation and growth we explain the quasi-continuous resistance variations and derive a simple analytical expression for the memristive effect. Our results suggest new opportunities for ferroelectrics as the hardware basis of future neuromorphic computational architectures

    Interferon Production and Signaling Pathways Are Antagonized during Henipavirus Infection of Fruit Bat Cell Lines

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    Bats are natural reservoirs for a spectrum of infectious zoonotic diseases including the recently emerged henipaviruses (Hendra and Nipah viruses). Henipaviruses have been observed both naturally and experimentally to cause serious and often fatal disease in many different mammal species, including humans. Interestingly, infection of the flying fox with henipaviruses occurs in the absence of clinical disease. The extreme variation in the disease pattern between humans and bats has led to an investigation into the effects of henipavirus infection on the innate immune response in bat cell lines. We report that henipavirus infection does not result in the induction of interferon expression, and the viruses also inhibit interferon signaling. We also confirm that the interferon production and signaling block in bat cells is not due to differing viral protein expression levels between human and bat hosts. This information, in addition to the known lack of clinical signs in bats following henipavirus infection, suggests that bats control henipavirus infection by an as yet unidentified mechanism, not via the interferon response. This is the first report of henipavirus infection in bat cells specifically investigating aspects of the innate immune system

    Association of limbic system-associated membrane protein (LSAMP) to male completed suicide

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    <p>Abstract</p> <p>Background</p> <p>Neuroimaging studies have demonstrated volumetric abnormalities in limbic structures of suicide victims. The morphological changes might be caused by some inherited neurodevelopmental defect, such as failure to form proper axonal connections due to genetically determined dysfunction of neurite guidance molecules. Limbic system-associated membrane protein (LSAMP) is a neuronal adhesive molecule, preferentially expressed in developing limbic system neuronal dendrites and somata. Some evidence for the association between LSAMP gene and behavior has come from both animal as well as human studies but further investigation is required. In current study, polymorphic loci in human LSAMP gene were examined in order to reveal any associations between genetic variation in <it>LSAMP </it>and suicidal behaviour.</p> <p>Methods</p> <p>DNA was obtained from 288 male suicide victims and 327 healthy male volunteers. Thirty SNPs from LSAMP gene and adjacent region were selected by Tagger algorithm implemented in Haploview 3.32. Genotyping was performed using the SNPlex™ (Applied Biosystems) platform. Data was analyzed by Genemapper 3.7, Haploview 3.32 and SPSS 13.0.</p> <p>Results</p> <p>Chi square test revealed four allelic variants (rs2918215, rs2918213, rs9874470 and rs4821129) located in the intronic region of the gene to be associated with suicide, major alleles being overrepresented in suicide group. However, the associations did not survive multiple correction test. Defining the haplotype blocks using confidence interval algorithm implemented in Haploview 3.32, we failed to detect any associated haplotypes.</p> <p>Conclusion</p> <p>Despite a considerable amount of investigation on the nature of suicidal behaviour, its aetiology and pathogenesis remain unknown. This study examined the variability in LSAMP gene in relation to completed suicide. Our results indicate that LSAMP might play a role in pathoaetiology of suicidal behaviour but further studies are needed to understand its exact contribution.</p

    U.S. academic libraries: understanding their web presence and their relationship with economic indicators

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s11192-013-1001-0The main goal of this research is to analyze the web structure and performance of units and services belonging to U.S. academic libraries in order to check their suitability for webometric studies. Our objectives include studying their possible correlation with economic data and assessing their use for complementary evaluation purposes. We conducted a survey of library homepages, institutional repositories, digital collections, and online catalogs (a total of 374 URLs) belonging to the 100 U.S. universities with the highest total expenditures in academic libraries according to data provided by the National Center for Education Statistics. Several data points were taken and analyzed, including web variables (page count, external links, and visits) and economic variables (total expenditures, expenditures on printed and electronic books, and physical visits). The results indicate that the variety of URL syntaxes is wide, diverse and complex, which produces a misrepresentation of academic libraries’ web resources and reduces the accuracy of web analysis. On the other hand, institutional and web data indicators are not highly correlated. Better results are obtained by correlating total library expenditures with URL mentions measured by Google (r = 0.546) and visits measured by Compete (r = 0.573), respectively. Because correlation values obtained are not highly significant, we estimate such correlations will increase if users can avoid linkage problems (due to the complexity of URLs) and gain direct access to log files (for more accurate data about visits).Orduña Malea, E.; Regazzi, JJ. (2014). U.S. academic libraries: understanding their web presence and their relationship with economic indicators. Scientometrics. 98(1):315-336. doi:10.1007/s11192-013-1001-0S315336981Adecannby, J. (2011). 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    State-of-the-art management of nasopharyngeal carcinoma: current and future directions

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    Nasopharyngeal carcinoma (NPC) is a distinct type of head and neck cancer. Approximately 70% of patients with newly diagnosed NPC present with locally advanced disease. Phase III clinical trials support the addition of chemotherapy to radiotherapy for the initial treatment of these patients. Once metastatic disease develops, practices become varied. Further experience needs to be gained with both targeted therapies and immunotherapy to gauge whether they will improve treatment outcomes in NPC
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