172 research outputs found

    Feeding rates of Aphyosemion geryyi (Cyprinodontidae) on mosquito larvae in the laboratory and in the field

    Get PDF
    L'analyse du contenu stomacal de trois populations d'#Aphyosemion geryi originaires de la Guinée (Conakry) a montré que cette espèce se nourrit principalement de petits crustacés, de formicidés et de larves de chironomes. La capacité prédatrice de ce poisson envers deux espèces de moustiques #Aedes aegypti et #Culex thalassius a été examinée par des expériences en laboratoire. La taille des proies, laquelle peut être en relation avec la mobilité des larves, est un facteur important pour déterminer la capacité prédatrice. #A. geryi, qui se nourrit aussi bien la nuit que le jour, présente cependant un maximum entre 10-19h00. Des expériences réalisées dans des habitats naturels montrent que ce poisson a un impact important sur les plus jeunes stades larvaires. Une réduction de 90% de la population de larves de culicidés a été obtenue pendant la période maximale de prise de nourriture. Au vu de ces résultats, cette espèce de #Cyprinodontidae$ pourrait être considérée pour une utilisation possible dans le contrôle biologique des larves de moustiques en Afrique de l'Ouest. (Résumé d'auteur

    Lack of effect of combination antibiotic therapy on mortality in patients with pneumococcal sepsis

    Get PDF
    In order to determine whether combination antibiotic therapy decreases mortality after severe pneumococcal infection, a retrospective study of a cohort of 1,840 adult patients with severe sepsis or septic shock enrolled in two multicenter clinical trials between 1994 and 1999 was conducted. Among 107 patients with monobacterial pneumococcal sepsis, the case-fatality rate was 20% (five of 25) for patients who received antibiotic monotherapy compared with 19.5% (16 of 82) for patients who received combination therapy (adjusted hazard ratio, 1.1; 95% CI, 0.4-3.1). Similarly, monotherapy did not increase the risk of death (adjusted hazard ratio, 1.0; 95% CI, 0.2-4.8) among bacteremic patients (n=75). However, the latter analysis may have been underpowered (power, 58%) to detect a difference in mortality. Overall, in contrast to recently published reports, these results suggest that combination antibiotic therapy does not decrease mortality after severe pneumococcal sepsi

    Culture change in elite sport performance teams: Examining and advancing effectiveness in the new era

    Get PDF
    Reflecting the importance of optimizing culture for elite teams, Fletcher and Arnold (2011) recently suggested the need for expertise in culture change. Acknowledging the dearth of literature on the specific process, however, the potential effectiveness of practitioners in this area is unknown. The present paper examines the activity's precise demands and the validity of understanding in sport psychology and organizational research to support its delivery. Recognizing that sport psychologists are being increasingly utilized by elite team management, initial evidence-based guidelines are presented. Finally, to stimulate the development of ecologically valid, practically meaningful knowledge, the paper identifies a number of future research directions

    SIRTA, a ground-based atmospheric observatory for cloud and aerosol research

    Get PDF
    Ground-based remote sensing observatories have a crucial role to play in providing data to improve our understanding of atmospheric processes, to test the performance of atmospheric models, and to develop new methods for future space-borne observations. Institut Pierre Simon Laplace, a French research institute in environmental sciences, created the Site Instrumental de Recherche par Télédétection Atmosphérique (SIRTA), an atmospheric observatory with these goals in mind. Today SIRTA, located 20km south of Paris, operates a suite a state-of-the-art active and passive remote sensing instruments dedicated to routine monitoring of cloud and aerosol properties, and key atmospheric parameters. Detailed description of the state of the atmospheric column is progressively archived and made accessible to the scientific community. This paper describes the SIRTA infrastructure and database, and provides an overview of the scientific research associated with the observatory. Researchers using SIRTA data conduct research on atmospheric processes involving complex interactions between clouds, aerosols and radiative and dynamic processes in the atmospheric column. Atmospheric modellers working with SIRTA observations develop new methods to test their models and innovative analyses to improve parametric representations of sub-grid processes that must be accounted for in the model. SIRTA provides the means to develop data interpretation tools for future active remote sensing missions in space (e.g. CloudSat and CALIPSO). SIRTA observation and research activities take place in networks of atmospheric observatories that allow scientists to access consistent data sets from diverse regions on the globe

    Development of Social Vocalizations in Mice

    Get PDF
    Adult mice are highly vocal animals, with both males and females vocalizing in same sex and cross sex social encounters. Mouse pups are also highly vocal, producing isolation vocalizations when they are cold or removed from the nest. This study examined patterns in the development of pup isolation vocalizations, and compared these to adult vocalizations. In three litters of CBA/CaJ mice, we recorded isolation vocalizations at ages postnatal day 5 (p5), p7, p9, p11, and p13. Adult vocalizations were obtained in a variety of social situations. Altogether, 28,384 discrete vocal signals were recorded using high-frequency-sensitive equipment and analyzed for syllable type, spectral and temporal features, and the temporal sequencing within bouts. We found that pups produced all but one of the 11 syllable types recorded from adults. The proportions of syllable types changed developmentally, but even the youngest pups produced complex syllables with frequency-time variations. When all syllable types were pooled together for analysis, changes in the peak frequency or the duration of syllables were small, although significant, from p5 through p13. However, individual syllable types showed different, large patterns of change over development, requiring analysis of each syllable type separately. Most adult syllables were substantially lower in frequency and shorter in duration. As pups aged, the complexity of vocal bouts increased, with a greater tendency to switch between syllable types. Vocal bouts from older animals, p13 and adult, had significantly more sequential structure than those from younger mice. Overall, these results demonstrate substantial changes in social vocalizations with age. Future studies are required to identify whether these changes result from developmental processes affecting the vocal tract or control of vocalization, or from vocal learning. To provide a tool for further research, we developed a MATLAB program that generates bouts of vocalizations that correspond to mice of different ages

    Results and Limits of Time Division Multiplexing for the BICEP Array High Frequency Receivers

    Full text link
    Time-Division Multiplexing is the readout architecture of choice for many ground and space experiments, as it is a very mature technology with proven outstanding low-frequency noise stability, which represents a central challenge in multiplexing. Once fully populated, each of the two BICEP Array high frequency receivers, observing at 150GHz and 220/270GHz, will have 7776 TES detectors tiled on the focal plane. The constraints set by these two receivers required a redesign of the warm readout electronics. The new version of the standard Multi Channel Electronics, developed and built at the University of British Columbia, is presented here for the first time. BICEP Array operates Time Division Multiplexing readout technology to the limits of its capabilities in terms of multiplexing rate, noise and crosstalk, and applies them in rigorously demanding scientific application requiring extreme noise performance and systematic error control. Future experiments like CMB-S4 plan to use TES bolometers with Time Division/SQUID-based readout for an even larger number of detectors.Comment: 10 pages, 7 figures, Submitted to Journal of Low Temperature Physic
    • …
    corecore