3,821 research outputs found

    New Measurements of Venus Winds with Ground-Based Doppler Velocimetry at CFHT

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    operations with observations from the ground using various techniques and spectral domains (Lellouch and Witasse, 2008). We present an analysis of Venus Doppler winds at cloud tops based on observations made at the Canada France Hawaii 3.6-m telescope (CFHT) with the ESPaDOnS visible spectrograph. These observations consisted of high-resolution spectra of Fraunhofer lines in the visible range (0.37-1.05 μm) to measure the winds at cloud tops using the Doppler shift of solar radiation scattered by cloud top particles in the observer's direction (Widemann et al., 2007, 2008). The observations were made during 19-20 February 2011 and were coordinated with Visual Monitoring Camera (VMC) observations by Venus Express. The complete optical spectrum was collected over 40 spectral orders at each point with 2-5 seconds exposures, at a resolution of about 80000. The observations included various points of the dayside hemisphere at a phase angle of 67°, between +10° and -60° latitude, in steps of 10° , and from +70° to -12° longitude relative to sub-Earth meridian in steps of 12°. The Doppler shift measured in scattered solar light on Venus dayside results from two instantaneous motions: (1) a motion between the Sun and Venus upper cloud particles; (2) a motion between the observer and Venus clouds. The measured Doppler shift, which results from these two terms combined, varies with the planetocentric longitude and latitude and is minimum at meridian ΦN = ΦSun - ΦEarth where the two components subtract to each other for a pure zonal regime. Due to the need for maintaining a stable velocity reference during the course of acquisition using high resolution spectroscopy, we measure relative Doppler shifts to ΦN. The main purpose of our work is to provide variable wind measurements with respect to the background atmosphere, complementary to simultaneous measurements made with the VMC camera onboard the Venus Express. We will present first results from this work, comparing with previous results by the CFHT/ESPaDOnS and VLT-UVES spectrographs (Machado et al., 2012), with Galileo fly-by measurements and with VEx nominal mission observations (Peralta et al., 2007, Luz et al., 2011). Acknowledgements: The authors acknowledge support from FCT through projects PTDC/CTE-AST/110702/2009 and PEst-OE/FIS/UI2751/2011. PM and TW also acknowledge support from the Observatoire de Paris. Lellouch, E., and Witasse, O., A coordinated campaign of Venus ground-based observations and Venus Express measurements, Planetary and Space Science 56 (2008) 1317-1319. Luz, D., et al., Venus's polar vortex reveals precessing circulation, Science 332 (2011) 577-580. Machado, P., Luz, D. Widemann, T., Lellouch, E., Witasse, O, Characterizing the atmospheric dynamics of Venus from ground-based Doppler velocimetry, Icarus, submitted. Peralta J., R. Hueso, A. Sánchez-Lavega, A reanalysis of Venus winds at two cloud levels from Galileo SSI images, Icarus 190 (2007) 469-477. Widemann, T., Lellouch, E., Donati, J.-F., 2008, Venus Doppler winds at Cloud Tops Observed with ESPaDOnS at CFHT, Planetary and Space Science, 56, 1320-1334

    The Importance of Comprehensive Assessment of the Sexually Abused Child

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    In the past few years public awareness of sexual abuse of children has increased, together with the recognition of its social, physical, and psychological effects (I). We must emphasize our role as diagnosticians in doing a comprehensive assessment of the sexually abused child. It is our professional responsibility to assess the general psychological status of the child before and after sexual abuse

    Matter-wave 2D solitons in crossed linear and nonlinear optical lattices

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    It is demonstrated the existence of multidimensional matter-wave solitons in a crossed optical lattice (OL) with linear OL in the xx-direction and nonlinear OL (NOL) in the yy-direction, where the NOL can be generated by a periodic spatial modulation of the scattering length using an optically induced Feshbach resonance. In particular, we show that such crossed linear and nonlinear OL allows to stabilize two-dimensional (2D) solitons against decay or collapse for both attractive and repulsive interactions. The solutions for the soliton stability are investigated analytically, by using a multi-Gaussian variational approach (VA), with the Vakhitov-Kolokolov (VK) necessary criterion for stability; and numerically, by using the relaxation method and direct numerical time integrations of the Gross-Pitaevskii equation (GPE). Very good agreement of the results corresponding to both treatments is observed.Comment: 8 pages (two-column format), with 16 eps-files of 4 figure

    First report of Metarhizium anisopliae IP 46 pathogenicity in adult Anopheles gambiae s.s. and An. arabiensis (Diptera; Culicidae).

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    The entomopathogenic fungus Metarhizium anisopliae isolate IP 46, originating from a soil sample collected in 2001 in the Cerrado of Central Brazil, was tested for its ability to reduce the survival of adult male and female Anopheles gambiae s.s. and An. arabiensis mosquitoes. A 6-h exposure to the fungus coated on test paper at a concentration of 3.3 x 106 conidia cm-2 reduced the daily survival of both mosquito species (HR = 3.14, p < 0.001), with higher risk of dying in An. gambiae s.s relative to An. arabiensis (HR = 1.38, p < 0.001). Fungal sporulation was observed in >95% of mosquito cadavers in the treatment groups. The results indicate that M. anisopliae IP 46 has the potential to be a bio-control agent for African malaria vector species, and is a suitable candidate for further research and development

    Evaluating the research productivity of a state university in Central Luzon, Philippines: Basis for policy recommendations

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    This descriptive study evaluated the research productivity of a state university in Central Luzon, Philippines, for the past five years (2016-2020) as basis for policy formulation. The study used document analysis to ascertain the research productivity in terms of: i) Number of papers published in refereed international journals such as Scopus and Commission on Higher Education (CHED) accredited journals; ii) Number of faculty researchers with publication to these journals; and iii) Total number of citations. The data were obtained primarily from online publications found in the Google Scholar and Scopus databases. Results revealed that the state university's research productivity is relatively high in terms of published papers in refereed international journals for the past five years. However, the published papers in Scopus-indexed journals and CHED accredited journals are relatively low. An average number of faculty researchers publish their works in reputable journals, but very few faculties publish in the journals recommended by the CHED. Likewise, the university had a remarkable research citation record for the past five years. The findings of this research have important implications for policy to improve research productivity and enhance the research culture in higher education institutions (HEIs). Such policies include the need to have strong support to faculty researchers, forge research collaborations, source external research funding, and establish a sound incentive mechanism

    Development of overturning circulation in sloping waterbodies due to surface cooling

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    This work was supported by the Swiss National Science Foundation (project Buoyancy driven nearshore transport in lakes, HYPOlimnetic THErmal SIphonS, HYPOTHESIS, reference 175919) and by the Physics of Aquatic Systems Laboratory (APHYS), EPFL.Cooling the surface of freshwater bodies, whose temperatures are above the temperature of maximum density, can generate differential cooling between shallow and deep regions. When surface cooling occurs over a long enough period, the thermally induced cross-shore pressure gradient may drive an overturning circulation, a phenomenon called ‘thermal siphon’. However, the conditions under which this process begins are not yet fully characterised. Here, we examine the development of thermal siphons driven by a uniform loss of heat at the air–water interface in sloping, stratified basins. For a two-dimensional framework, we derive theoretical time and velocity scales associated with the transition from Rayleigh–Bénard type convection to a horizontal overturning circulation across the shallower sloping basin. This transition is characterised by a three-way horizontal momentum balance, in which the cross-shore pressure gradient balances the inertial terms before reaching a quasi-steady regime. We performed numerical and field experiments to test and show the robustness of the analytical scaling, describe the convective regimes and quantify the cross-shore transport induced by thermal siphons. Our results are relevant for understanding the nearshore fluid dynamics induced by nighttime or seasonal surface cooling in lakes and reservoirs.Swiss National Science Foundation (SNSF) European Commission 175919Physics of Aquatic Systems Laboratory (APHYS), EPF

    Distribuição de Phytophthora nicotianae e P. boehmeriae nas plantações brasileiras de acácia-negra.

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    Duas espécies de Phytophthora, P. nicotianae e P. boehmeriae já foram identificadas como agentes da gomose da acácia-negra no Brasil. Visando determinar a distribuição dessas espécies nas plantações brasileiras de acácia-negra foi realizado um levantamento e coleta de amostras em 23 plantações localizadas em nove municípios do Rio Grande do Sul e em duas áreas experimentais, em dois municípios do estado do Paraná. As culturas obtidas foram identificadas por suas características culturais e morfológicas, principalmente produção, forma e dimensões dos esporângios, e formação de oósporos. Phytophthora nicotianae foi a espécie predominante, estando presente em 100% das plantações amostradas, enquanto P. boehmeriae foi isolada apenas de 10% das amostras, estando presente apenas nos municípios de Piratini, Cristal e Cerro Grande do Sul, no Rio Grande do Sul. No estado do Paraná somente P. nicotianae foi assinalada até o momento. Observou-se diferenciação na sintomatologia causada pelas espécies. Phytophthora nicotianae foi responsável pela gomose basal das árvores, enquanto P. boehmeriae estava associada a gomose generalizada.bitstream/item/29179/1/11.pd

    Defining human-machine micro-task workflows for constitution making

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    This paper presents a novel task-oriented approach to crowdsource the drafting of a constitution. By considering micro-tasking as a particular form of crowdsourcing, it defines a workflow-based approach based on Onto2Flow, an ontology that models the basic concepts and roles to represent workflow-definitions. The approach is then applied to a prototype platform for constitution-making where human workers are requested to contribute to a set of tasks. The paper concludes by discussing previous approaches to participatory constitution-making and identifying areas for future work.This work is part-funded by FEDER Funds, by the ERDF (European Regional Development Fund) through the COMPETE Programme (Operational Programme for Competitiveness) and by National Funds through the FCT (Portuguese Foundation for Science and Technology) within the project FCOMP-01-0124-FEDER-028980 (PTDC/EEI-SII/1386/2012). The work of Nuno Luz is supported by the doctoral grant SFRH/BD/70302/2010. The work of Marta Poblet draws from previous research within the framework of the project “Crowdsourcing: instrumentos semánticos para el desarrollo de la participación y la mediación online” (DER 2012-39492-C02-01) by the Spanish Ministry of Economy and Competitiveness.info:eu-repo/semantics/publishedVersio

    A gomose da acácia-negra no Brasil.

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    A acácia-negra (Acacia mearnsii) é cultivada no Brasil, especialmente no Estado do Rio Grande do Sul, visando tanto à produção de tanino, a partir da casca, quanto o uso da madeira para papel, celulose, carvão, lenha e chapas de aglomerados. A gomose causada por Phytophthora nicotianae e P. boehmeriae, é o seu principal problema fitossanitário. Discute-se nesta revisão a existência de dois padrões distintos de sintomatologia da gomose de Phytophthora que têm sido observados nas plantações brasileiras: gomose basal, associada a P. nicotianae, e gomose generalizada, mais associada a P. boehmeriae. São discutidos aspectos relacionados à etiologia, à epidemiologia e às estratégias de controle
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