2,245 research outputs found

    Dispersal of _Aedes aegypti_: field study in temperate areas and statistical approach

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    We studied the dispersion of _Aedes aegypti_ during egg laying in natural conditions. Two independent experiments involving mosquitoes dispersing from urbanization towards adjacent un-urbanized areas were carried out and analyzed in statistical terms. We find relations between stochastic variables related to the egg laying mosquito activity (ELMA), useful to assess dispersion probabilities, despite the lack of knowledge of the total number of ovipositions in the zone. We propose to evaluate the activity as minus the logarithm of the fraction of negative ovitraps at different distances from buildings. We also estimate the average number of eggs laid per oviposition using a regression between the ELMA and the number of eggs found. Three zones with different oviposition activity were determined: a corridor surrounding the urbanized area, a second region between 10m and 25m and the third region extending from 30m to 45m from the urbanization. The landscape (plant cover) and the human activity in the area appear to have an influence in the dispersal of _Aedes aegypti_

    Contamination

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    Soil contamination occurs when substances are added to soil, resulting in increases in concentrations above background or reference levels. Pollution may follow from contamination when contaminants are present in amounts that are detrimental to soil quality and become harmful to the environment or human health. Contamination can occur via a range of pathways including direct application to land and indirect application from atmospheric deposition. Contamination was identified by SEPA (2001) as a significant threat to soil quality in many parts of Scotland. Towers et al. (2006) identified four principal contamination threats to Scottish soils: acidification; eutrophication; metals; and pesticides. The Scottish Soil Framework (Scottish Government, 2009) set out the potential impact of these threats on the principal soil functions. Severe contamination can lead to “contaminated land” [as defined under Part IIA of the Environmental Protection Act (1990)]. This report does not consider the state and impacts of contaminated land on the wider environment in detail. For further information on contaminated land, see ‘Dealing with Land Contamination in Scotland’ (SEPA, 2009). This chapter considers the causes of soil contamination and their environmental and socio-economic impacts before going on to discuss the status of, and trends in, levels of contaminants in Scotland’s soils

    Sources of semiochemicals mediating host finding in Callosobruchus chinensis (Coleoptera: Bruchidae)

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    Bruchid pests such as Callosobruchus chinensis (Linnaeus) endanger stored legume seeds throughout the tropical belt. The chemical composition of the headspace volatiles from healthy and fourth instar larvae-infested cowpea seeds were identified, characterized, and compared using gas chromatography-mass spectrometry. Y-tube olfactometer bioassays were performed to evaluate the effect of these chemicals on the orientation of conspecific adult females. Analysis of volatiles released from healthy and infested seeds revealed qualitative differences for three out of the 17 compounds identified. Dimethyl disulphide, isobutenyl methyl ketone and methyl trisulphide were found only in the blend emitted from infested but not from healthy seeds. Quantitative differences were apparent for tridecane which was released in larger amounts from infested seeds. While volatiles collected from healthy seeds were attractive to female bruchids, volatiles collected from infested seeds were repellent. To test the hypothesis that the qualitative differences in the chemical composition found may be due to insect-derived components, the volatiles from frass and fourth instar larvae combined were analysed. These volatiles contained both of the sulphides emitted from infested seed but not from healthy seeds. Although a limited induction of volatiles from cowpea seeds cannot be excluded, it is postulated that behavioural differences of the female weevils are largely due to insect-derived semiochemicals. The potential use of such semiochemicals as part of an integrated pest management strategy is discusse

    Coordinate Singularities in Harmonically-sliced Cosmologies

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    Harmonic slicing has in recent years become a standard way of prescribing the lapse function in numerical simulations of general relativity. However, as was first noticed by Alcubierre (1997), numerical solutions generated using this slicing condition can show pathological behaviour. In this paper, analytic and numerical methods are used to examine harmonic slicings of Kasner and Gowdy cosmological spacetimes. It is shown that in general the slicings are prevented from covering the whole of the spacetimes by the appearance of coordinate singularities. As well as limiting the maximum running times of numerical simulations, the coordinate singularities can lead to features being produced in numerically evolved solutions which must be distinguished from genuine physical effects.Comment: 21 pages, REVTeX, 5 figure

    A randomised trial evaluating Bevacizumab as adjuvant therapy following resection of AJCC stage IIB, IIC and III cutaneous melanoma : an update

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    At present, there are no standard therapies for the adjuvant treatment of malignant melanoma. Patients with primary tumours with a high-Breslow thickness (stages IIB and IIC) or with resected loco-regional nodal disease (stage III) are at high risk of developing metastasis and subsequent disease-related death. Given this, it is important that novel therapies are investigated in the adjuvant melanoma setting. Since angiogenesis is essential for primary tumour growth and the development of metastasis, anti-angiogenic agents are attractive potential therapeutic candidates for clinical trials in the adjuvant setting. Therefore, we initiated a phase II trial in resected high-risk cutaneous melanoma, assessing the efficacy of bevacizumab versus observation. In the interim safety data analysis, we demonstrate that bevacizumab is a safe therapy in the adjuvant melanoma setting with no apparent increase in the surgical complication rate after either primary tumour resection and/or loco-regional lymphadenectomy

    Relativistic effects in the processes of heavy quark fragmentation

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    In the framework based on the quasipotential method and relativistic quark model a new covariant expression for the heavy quark fragmentation amplitude to fragment into the pseudoscalar and vector S-wave heavy mesons is obtained. It contains all possible relativistic corrections including the terms connected with the transformation law of the bound state wave function to the reference frame of the moving meson. Relativistic corrections of order {\bf p}^2/m^2 to the heavy quark fragmentation distributions into (\bar c c), (\bar b c) and (\bar b b) states are calculated as functions of the longitudinal momentum fraction z and the transverse momentum p_T relative to the jet axis.Comment: 23 pages, 6 figure

    New explicit spike solution -- non-local component of the generalized Mixmaster attractor

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    By applying a standard solution-generating transformation to an arbitrary vacuum Bianchi type II solution, one generates a new solution with spikes commonly observed in numerical simulations. It is conjectured that the spike solution is part of the generalized Mixmaster attractor.Comment: Significantly revised. Colour figures simplified to accommodate non-colour printin

    El poder transformador del teatro en la expresi?n oral y corporal de los ni?os de grado primero del Colegio Americano de Pereira

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    229 p. Recurso Electr?nicoEl presente proyecto El poder transformador del teatro en la expresi?n oral y corporal de los ni?os y ni?as del grado primero del colegio Americano de la ciudad de Pereira, toma las artes como herramienta conductora y formadora, apoyando los diferentes procesos acad?micos de la instituci?n en pro de una formaci?n integral en ellos y bas?ndose en el teatro como eje articulador en la construcci?n de la personalidad, las cualidades y aptitudes desde ?l mismo y hacia los dem?s. El teatro es entonces el que permite influir en las diferentes expresiones del ni?o, por medio de la implementaci?n de estrategias l?dicas a partir de la danza, la m?sica, la poes?a, la literatura y las manualidades convirti?ndose estas en actividades integradoras y fortalecedoras de las tem?ticas acad?micas y reflexivas de la instituci?n, innovando permanentemente en la formaci?n integral de los estudiantes no solo del grado primero sino tambi?n en estudiantes de otros grados, donde uno de los grandes prop?sitos es fortalecer su desempe?o como ser social y lo haga participe activo de su propio aprendizaje, a que disfrute de su ambiente escolar, a que se convierta en un ser cr?tico activo y constructivo en el aula. Palabras clave: herramienta, corporal, verbal, artes, formaci?n, teatro, estrategias, danza, literatura, m?sica, articulador y construcci?n,This project called The power transformer theater in body and verbal expression of children in the first grade of the College Americano in the city of Pereira, takes the arts as conductive and forming tool, supporting different academic processes of the institution pro a comprehensive education of them and based on the theater as the linchpin in building the personality, qualities and skills from himself and toward others. The theater is then, which allows to influence the different expressions of the child, through the implementation of recreational activities from dance strategies, music, poetry, literature and crafts becoming these in integrating and fortifying activities of the academic and reflective thematic of the institution, constantly innovating in the integral formation of students, not only the first grade but also students from other grades, where one of the main purposes is to strengthen its performance as a social being and make him an active participant in their own learning, to enjoy the school environment, to become an active and constructive being in the classroom. Key Words: tool, bodily, verbal, Arts, training, theater, strategies, dance, literature, music, articulator and constructio

    Response of female Cydia molesta (Lepidoptera: Tortricidae) to plant derived volatiles

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    Peach shoot volatiles were attractive to mated female oriental fruit moth, Cydia molesta (Busck), in a dual choice arena. No preference was observed between leaf odours from the principle host plant, peach, and the secondary host plant, apple. Twenty-two compounds were identified in headspace volatiles of peach shoots using gas chromatography-mass spectrometry. Green leaf volatiles accounted for more than 50% of the total emitted volatiles. A bioassay-assisted fractionation using different sorbent polymers indicated an attractant effect of compounds with a chain length of 6-8 carbon atoms. The major compounds of this fraction were tested either singly or in combinations for behavioural response of females. Significant bioactivity was found for a three-component mixture of (Z)-3-hexen-1-yl acetate, (Z)-3-hexen-1-ol and benzaldehyde in a 4:1:1 ratio. This synthetic mixture elicited a similar attractant effect as the full natural blend from peach shoots as well as the bioactive fractio

    Manufacture of Gowdy spacetimes with spikes

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    In numerical studies of Gowdy spacetimes evidence has been found for the development of localized features (spikes) involving large gradients near the singularity. The rigorous mathematical results available up to now did not cover this kind of situation. In this work we show the existence of large classes of Gowdy spacetimes exhibiting features of the kind discovered numerically. These spacetimes are constructed by applying certain transformations to previously known spacetimes without spikes. It is possible to control the behaviour of the Kretschmann scalar near the singularity in detail. This curvature invariant is found to blow up in a way which is non-uniform near the spike in some cases. When this happens it demonstrates that the spike is a geometrically invariant feature and not an artefact of the choice of variables used to parametrize the metric. We also identify another class of spikes which are artefacts. The spikes produced by our method are compared with the results of numerical and heuristic analyses of the same situation.Comment: 25 page
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