1,445 research outputs found

    Geomagnetic effects observed by the Codalema experiment

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    6 pagesInternational audienceThe CODALEMA experiment is measuring transient radio emissions associated to extended air showers produced by high energy cosmic rays. The experimental setup installed at the Nancay Radio Observatory in France has recently undergone hardware upgrades and an extension of the surfaces covered by both the antenna and the scintillator detector arrays. The experimental data allow to investigate the main features of these radio signals and the underlying electric field production mechanisms. Some of the latest experimental results of CODALEMA are presented. They have been analyzed assuming a linear dependence of the electric field with respect to v ^ B. Within the CODALEMA observation conditions at Nancay, the detection eficiency, the arrival direction distribution and the polarity of the radio signals can be interpreted in terms of a geomagnetic effect. A R&D effort is currently underway to develop the hardware elements for the deployment of a large detector array based on active antennas. The main features of the first prototype of the CODALEMA autonomous station are briefly described

    Surrounding effects and sensitivity of the CODALEMA experiment

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    International audienceFuture autonomous systems of cosmic ray radiodetection will be installed over large areas, encountering various environmental and noise conditions. It is thus essential to check and evaluate the influence of the vicinity on the sensitivity of detection. In this paper, the main environmental influences on the performances of the CODALEMA experiment are presented. It will be shown that the performances and sensitivity of the detector are not affected by the environment, and that the new CODALEMA autonomous detection station can reach the ultimate accessible sensitivity even in a quite noisy environment. This allows deconvolving the detector's response and recovering the real spectral characteristics of the cosmic ray air showers

    Chocolate, Air Pollution and Children's Neuroprotection: What Cognition Tools should be at Hand to Evaluate Interventions?

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    Indexación: Web of ScienceMillions of children across the world are exposed to multiple sources of indoor and outdoor air pollutants, including high concentrations of fine particulate matter (PM2.5) and ozone (O-3). The established link between exposure to PM2.5, brain structural, volumetric and metabolic changes, severe cognitive deficits (1.5-2 SD from average IQ) in APOE 4 heterozygous females with >75 - <94% BMI percentiles, and the presence of Alzheimer's disease (AD) hallmarks in urban children and young adults necessitates exploration of ways to protect these individuals from the deleterious neural effects of pollution exposure. Emerging research suggests that cocoa interventions may be a viable option for neuroprotection, with evidence suggesting that early cocoa interventions could limit the risk of cognitive and developmental concerns including: endothelial dysfunction, cerebral hypoperfusion, neuroinflammation, and metabolic detrimental brain effects. Currently, however, it is not clear how early we should implement consumption of cocoa to optimize its neuroprotective effects. Moreover, we have yet to identify suitable instruments for evaluating cognitive responses to these interventions in clinically healthy children, teens, and young adults. An approach to guide the selection of cognitive tools should take into account neuropsychological markers of cognitive declines in patients with Alzheimer's neuropathology, the distinct patterns of memory impairment between early and late onset AD, and the key literature associating white matter integrity and poor memory binding performance in cases of asymptomatic familial AD. We highlight potential systemic and neural benefits of cocoa consumption. We also highlight Working Memory Capacity (WMC) and attention control tasks as opened avenues for exploration in the air pollution scenario. Exposures to air pollutants during brain development have serious brain consequences in the short and long term and reliable cognition tools should be at hand to evaluate interventions.http://journal.frontiersin.org/article/10.3389/fphar.2016.00232/ful

    Metabolic and behavioral compensations in response to caloric restriction: Implications for the maintenance of weight loss

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    BackgroundMetabolic and behavioral adaptations to caloric restriction (CR) in free-living conditions have not yet been objectively measured.Methodology and principal findingsForty-eight (36.8+/-1.0 y), overweight (BMI 27.8+/-0.7 kg/m(2)) participants were randomized to four groups for 6-months;Controlenergy intake at 100% of energy requirements; CR: 25% calorie restriction; CR+EX: 12.5% CR plus 12.5% increase in energy expenditure by structured exercise; LCD: low calorie diet (890 kcal/d) until 15% weight reduction followed by weight maintenance. Body composition (DXA) and total daily energy expenditure (TDEE) over 14-days by doubly labeled water (DLW) and activity related energy activity (AREE) were measured after 3 (M3) and 6 (M6) months of intervention. Weight changes at M6 were -1.0+/-1.1% (CONTROL), -10.4+/-0.9% (CR), -10.0+/-0.8% (CR+EX) and -13.9+/-0.8% (LCD). At M3, absolute TDEE was significantly reduced in CR (-454+/-76 kcal/d) and LCD (-633+/-66 kcal/d) but not in CR+EX or controls. At M6 the reduction in TDEE remained lower than baseline in CR (-316+/-118 kcal/d) and LCD (-389+/-124 kcal/d) but reached significance only when CR and LCD were combined (-351+/-83 kcal/d). In response to caloric restriction (CR/LCD combined), TDEE adjusted for body composition, was significantly lower by -431+/-51 and -240+/-83 kcal/d at M3 and M6, respectively, indicating a metabolic adaptation. Likewise, physical activity (TDEE adjusted for sleeping metabolic rate) was significantly reduced from baseline at both time points. For control and CR+EX, adjusted TDEE (body composition or sleeping metabolic rate) was not changed at either M3 or M6.ConclusionsFor the first time we show that in free-living conditions, CR results in a metabolic adaptation and a behavioral adaptation with decreased physical activity levels. These data also suggest potential mechanisms by which CR causes large inter-individual variability in the rates of weight loss and how exercise may influence weight loss and weight loss maintenance.Trial registrationClinicalTrials.gov NCT00099151.Leanne M. Redman, Leonie K. Heilbronn, Corby K. Martin, Lilian de Jonge, Donald A. Williamson, James P. Delany, Eric Ravussin, for the Pennington CALERIE tea

    Perfil epidemiológico de enfermedades de las abejas adultas en diferentes regiones del centro de Portugal

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    The aim of this study was to determine the prevalence of the adult honey bee's diseases at the Central Region of Portugal. Adult bee's samples were collected and analysed at the Laboratory of Honey Bee Pathology at Escola Superior Agraria de Bragança (LPAESAB). Samples were processed for epidemiological characterization of diseases of adult honey bees. In general, the prevalence of Varroa mites and Nosemosis increased over the years. Also, the results attained show that Varroatosis, Nosemosis and Myasis, occur along all the years and seasons. The diagnosis of Varroatosis and Nosemosis were higher (P<0,05) during Autumn than in the summer The Varroatosis and Nosemosis are both the major diseases of the adult honey bees presenting the higher concerns at regional and national level. Positive cases of Acarapisosis are indicative of a failure in acaricide treatment. We conclude that higher efforts are needed in order to define the strategies for the control of these diseases.info:eu-repo/semantics/publishedVersio

    Immunization expands B cells specific to HIV-1 V3 glycan in mice and macaques.

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    Broadly neutralizing monoclonal antibodies protect against infection with HIV-1 in animal models, suggesting that a vaccine that elicits these antibodies would be protective in humans. However, it has not yet been possible to induce adequate serological responses by vaccination. Here, to activate B cells that express precursors of broadly neutralizing antibodies within polyclonal repertoires, we developed an immunogen, RC1, that facilitates the recognition of the variable loop 3 (V3)-glycan patch on the envelope protein of HIV-1. RC1 conceals non-conserved immunodominant regions by the addition of glycans and/or multimerization on virus-like particles. Immunization of mice, rabbits and rhesus macaques with RC1 elicited serological responses that targeted the V3-glycan patch. Antibody cloning and cryo-electron microscopy structures of antibody-envelope complexes confirmed that immunization with RC1 expands clones of B cells that carry the anti-V3-glycan patch antibodies, which resemble precursors of human broadly neutralizing antibodies. Thus, RC1 may be a suitable priming immunogen for sequential vaccination strategies in the context of polyclonal repertoires

    Copper-containing mesoporous bioactive glass promotes angiogenesis in an in vivo zebrafish model

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    The osteogenic and angiogenic responses of organisms to the ionic products of degradation of bioactive glasses (BGs) are being intensively investigated. The promotion of angiogenesis by copper (Cu) has been known for more than three decades. This element can be incorporated to delivery carriers, such as BGs, and the materials used in biological assays. In this work, Cu-containing mesoporous bioactive glass (MBG) in the SiO2-CaO-P2O5 compositional system was prepared incorporating 5% mol Cu (MBG-5Cu) by replacement of the corresponding amount of Ca. The biological effects of the ionic products of MBG biodegradation were evaluated on a well-known endothelial cell line, the bovine aorta endothelial cells (BAEC), as well as in an in vivo zebrafish (Danio rerio) embryo assay. The results suggest that ionic products of both MBG (Cu free) and MBG-5Cu materials promote angiogenesis. In vitro cell cultures show that the ionic dissolution products of these materials are not toxic and promote BAEC viability and migration. In addition, the in vivo assay indicates that both exposition and microinjection of zebrafish embryos with Cu free MBG material increase vessel number and thickness of the subintestinal venous plexus (SIVP), whereas assays using MBG-5Cu enhance this effect.The authors gratefully acknowledge the financial support provided by the Andalusian Ministry of Economy, Science and Innovation (Proyectos Excelencia Grants no. P10-CTS-6681 and no. P12-CTS-1507) and Spanish Ministry of Economy and Competitivity (BIO2014-56092-R). LBRS acknowledges the CONACYT-Mexico Fellowship PhD Program
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