201 research outputs found

    High-Field A-15 Superconductors Prepared from Intermediate Compound(High Field Superconductors)

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    A15 Nb_3(Al, Ge) and Nb_3Sn have been easily synthesized starting from Nb_2(Al, Ge) and Nb_6Sn_5 intermediate compound powder, respectively. The intermediate compound powder was mixed with Nb powder by a ball mill in Ar atmosphere. The mixed powder was encased in a Nb or Ta tube, and then fabricated into a tape without intermediate annealing. The mechanical mixing of powders promotes the formation of A15 phase in subsequent reaction treatment. The bulk sintered specimens show higher onset T_c but broader T_c transition than tape specimens. In the Nb_3(Al, Ge) tape reacted at 1300℃, a J_c of over 2.7×10^4 A/cm^2 has been obtained at 4, 2K and 23T. The addition of MgO powder enhances J_c and reduces the peak effect in the Nb_3(Al, Ge) tape. The T_c of Nb_3Sn tape prepared by present process is appreciably higher than that of bronze-processed Nb_3Sn. Even pure Nb_3Sn tape shows Bc_2 of nearly 25T at 4.2K after the reaction at 900℃. The present A15 Nb_3(Al, Ge) and Nb_3Sn tapes seem to be promising for generating 20T at 4.2K

    Association between labour market trends and trends in young people's mental health in ten European countries 1983-2005

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    <p>Abstract</p> <p>Background</p> <p>Mental health problems have become more common among young people over the last twenty years, especially in certain countries. The reasons for this have remained unclear. The hypothesis tested in this study is that national trends in young people's mental health are associated with national trends in young people's labour market.</p> <p>Methods</p> <p>National secular changes in the proportion of young people with mental health problems and national secular labour market changes were studied from 1983 to 2005 in Austria, Belgium, Denmark, Finland, Hungary, Norway, Spain, Sweden, Switzerland and the United Kingdom.</p> <p>Results</p> <p>The correlation between the national secular changes in the proportion of young people not in the labour force and the national secular changes in proportion of young people with mental health symptoms was 0.77 for boys and 0.92 for girls.</p> <p>Conclusion</p> <p>Labour market trends may have contributed to the deteriorating trend in mental health among young people. A true relationship, should other studies confirm it, would be an important aspect to take into account when forming labour market policies or policies concerning the delivery of higher education.</p

    Assessment of Yellow Fever Epidemic Risk: An Original Multi-criteria Modeling Approach

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    This article describes the use of an original modeling approach to assess the risk of yellow fever (YF) epidemics. YF is a viral hemorrhagic fever responsible in past centuries for devastating outbreaks. Since the 1930s, a vaccine has been available that protects the individual for at least 10 years, if not for life. However, immunization of populations in African countries was gradually discontinued after the 1960s. With the decrease in immunity against YF in African populations the disease reemerged in the 1980s. In 2005, WHO, UNICEF, and the GAVI Alliance decided to support preventive vaccination of at-risk populations in West African endemic countries in order to tackle the reemergence of YF and reduce the risk of urban YF outbreaks. Financial resources were made available to scale up a global YF vaccine stockpile and to support countries with limited resources in the management of preventive vaccination campaigns. This article describes the process we used to determine the most at-risk populations using a mathematical model to prioritize targeted immunization campaigns. We believe that this approach could be useful for other diseases for which decision making process is difficult because of limited data availability, complex risk variables, and a need for rapid decisions and implementation

    Software project planning through comparison of Bio-inspired algorithms

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    Currently many organizations have adopted the development of software projects with agile methodologies, particularly Scrum, which has more than 20 years of development. In these methodologies, software is developed iteratively and delivered to the client in increments called releases. In the releases, the goal is to develop system functionality that quickly adds value to the client’s business. At the beginning of the project, one or more releases are planned. For solving the problem of replanning in the context of releases, a model is proposed considering the characteristics of agile development using Scrum. The results obtained show that the algorithm takes a little less than 7 min for solutions that propose replanning composed by 16 sprints, which is equivalent to 240 days of project. They show that applying a repair operator increases the hypervolume qualit

    Perceived academic performance as an indicator of risk of attempted suicide in young adolescents

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    This study investigated perceived academic performance and self-reported suicidal behavior in adolescents (n=2,596), mean age 13 years, from 27 South Australian high schools. Groups perceiving their academic performance as failing, below average, average and above average were significantly different on measures of self-esteem, locus of control, depressive symptoms, suicidal thoughts, plans, threats, deliberate self-injury, and suicide attempts. Multivariate logistic regression analyses revealed that failing academic performance (compared to above average) is associated with a fivefold increased likelihood of a suicide attempt, controlling for self-esteem, locus of control and depressive symptoms. Teachers should note that a student presenting with low selfesteem, depressed mood and perceptions of failure may be at increased risk for suicidal thoughts and behaviors, and need referral for clinical assessment

    Heart rate variability in non-apneic snorers and controls before and after continuous positive airway pressure

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    BACKGROUND: We hypothesized that sympathetic nervous system activity (SNSA) is increased and parasympathetic nervous system activity (PNSA) is decreased during non-rapid eye movement (NREM) sleep in non-apneic, otherwise healthy, snoring individuals compared to control. Moreover, we hypothesized that these alterations in snoring individuals would be more evident during non-snoring than snoring when compared to control. METHODS: To test these hypotheses, heart rate variability was used to measure PNSA and SNSA in 11 normotensive non-apneic snorers and 12 control subjects before and 7-days after adapting to nasal continuous positive airway pressure (nCPAP). RESULTS: Our results showed that SNSA was increased and PNSA was decreased in non-apneic snorers during NREM compared to control. However, these changes were only evident during the study in which snoring was eliminated with nCPAP. Conversely, during periods of snoring SNSA and PNSA were similar to measures obtained from the control group. Additionally, within the control group, SNSA and PNSA did not vary before and after nCPAP application. CONCLUSION: Our findings suggest that long-lasting alterations in autonomic function may exist in snoring subjects that are otherwise healthy. Moreover, we speculate that because of competing inputs (i.e. inhibitory versus excitatory inputs) to the autonomic nervous system during snoring, the full impact of snoring on autonomic function is most evident during non-snoring periods

    Alterations in the Aedes aegypti Transcriptome during Infection with West Nile, Dengue and Yellow Fever Viruses

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    West Nile (WNV), dengue (DENV) and yellow fever (YFV) viruses are (re)emerging, mosquito-borne flaviviruses that cause human disease and mortality worldwide. Alterations in mosquito gene expression common and unique to individual flaviviral infections are poorly understood. Here, we present a microarray analysis of the Aedes aegypti transcriptome over time during infection with DENV, WNV or YFV. We identified 203 mosquito genes that were ≥5-fold differentially up-regulated (DUR) and 202 genes that were ≥10-fold differentially down-regulated (DDR) during infection with one of the three flaviviruses. Comparative analysis revealed that the expression profile of 20 DUR genes and 15 DDR genes was quite similar between the three flaviviruses on D1 of infection, indicating a potentially conserved transcriptomic signature of flaviviral infection. Bioinformatics analysis revealed changes in expression of genes from diverse cellular processes, including ion binding, transport, metabolic processes and peptidase activity. We also demonstrate that virally-regulated gene expression is tissue-specific. The overexpression of several virally down-regulated genes decreased WNV infection in mosquito cells and Aedes aegypti mosquitoes. Among these, a pupal cuticle protein was shown to bind WNV envelope protein, leading to inhibition of infection in vitro and the prevention of lethal WNV encephalitis in mice. This work provides an extensive list of targets for controlling flaviviral infection in mosquitoes that may also be used to develop broad preventative and therapeutic measures for multiple flaviviruses

    Ebola and Marburg Hemorrhagic Fevers: Neglected Tropical Diseases?

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    Ebola hemorrhagic fever (EHF) and Marburg hemorrhagic fever (MHF) are rare viral diseases, endemic to central Africa. The overall burden of EHF and MHF is small in comparison to the more common protozoan, helminth, and bacterial diseases typically referred to as neglected tropical diseases (NTDs). However, EHF and MHF outbreaks typically occur in resource-limited settings, and many aspects of these outbreaks are a direct consequence of impoverished conditions. We will discuss aspects of EHF and MHF disease, in comparison to the “classic” NTDs, and examine potential ways forward in the prevention and control of EHF and MHF in sub-Saharan Africa, as well as examine the potential for application of novel vaccines or antiviral drugs for prevention or control of EHF and MHF among populations at highest risk for disease
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