810 research outputs found

    Doses, modos de aplicação de calcário e índices de acidez do solo para produção de soja e milho na Região da Zona da mata de Rondônia: respostas das plantas às doses e modos de aplicação de calcário em solo cultivado no sistema plantio direto.

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    O objetivo do trabalho foi de avaliar a resposta de soja e milho a diferentes doses de calcário, correlacionando-as com a saturação por bases (V%) e com o modo de incorporação (sistema mínimo, sistema tradicional e sem preparo), afim de estabelecer os melhores níveis de pH, dose e modo de aplicação do calcário para a região e sua influencia na disponibilidade dos nutrientes. O experimento foi instalado na área experimental do Campus de Agronomia em um Latossolo Vermelho-Amarelo distrófico típico, que foi cultivado com soja e milho (Safra 10/11). O modo de aplicação de calcário e a dose não resultaram em diferença na produtividade de milho. Para a soja a aplicação superficial de calcário proporcionou maior rendimento em relação ao sistema tradicional. A calagem proporcionou aumento nos níveis de V%, pH e Ca+Mg, demonstrando também eficiência na neutralização do alumínio

    Capital structure and its determinants in the United Kingdom – a decompositional analysis

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    Prior research on capital structure by Rajan and Zingales (1995) suggests that the level of gearing in UK companies is positively related to size and tangibility, and negatively correlated with profitability and the level of growth opportunities. However, as argued by Harris and Raviv (1991), 'The interpretation of results must be tempered by an awareness of the difficulties involved in measuring both leverage and the explanatory variables of interest'. In this study the focus is on the difficulties of measuring gearing, and the sensitivity of Rajan and Zingales' results to variations in gearing measures are tested. Based on an analysis of the capital structure of 822 UK companies, Rajan and Zingales' results are found to be highly definitional-dependent. The determinants of gearing appear to vary significantly, depending upon which component of debt is being analysed. In particular, significant differences are found in the determinants of long- and short-term forms of debt. Given that trade credit and equivalent, on average, accounts for more than 62% of total debt, the results are particularly sensitive to whether such debt is included in the gearing measure. It is argued, therefore, that analysis of capital structure is incomplete without a detailed examination of all forms of corporate debt

    Constellations of identity: place-ma(r)king beyond heritage

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    This paper will critically consider the different ways in which history and belonging have been treated in artworks situated in the Citadel development in Ayr on the West coast of Scotland. It will focus upon one artwork, Constellation by Stephen Hurrel, as an alternative to the more conventional landscapes of heritage which are adjacent, to examine the relationship between personal history and place history and argue the primacy of participatory process in the creation of place and any artwork therein. Through his artwork, Hurrel has attempted to adopt a material process through which place can be created performatively but, in part due to its non-representational form, proves problematic, aesthetically and longitudinally, in wholly engaging the community. The paper will suggest that through variants of ‘new genre public art’ such as this, personal and place histories can be actively re-created through the redevelopment of contemporary urban landscapes but also highlight the complexities and indeterminacies involved in the relationship between artwork, people and place

    Investigating situated cultural practices through cross-sectoral digital collaborations: policies, processes, insights

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    The (Belfast) Good Friday Agreement represents a major milestone in Northern Ireland's recent political history, with complex conditions allowing for formation of a ‘cross-community’ system of government enabling power sharing between parties representing Protestant/loyalist and Catholic/nationalist constituencies. This article examines the apparent flourishing of community-focused digital practices over the subsequent ‘post-conflict’ decade, galvanised by Northern Irish and EU policy initiatives armed with consolidating the peace process. Numerous digital heritage and storytelling projects have been catalysed within programmes aiming to foster social processes, community cohesion and cross-community exchange. The article outlines two projects—‘digital memory boxes’ and ‘interactive galleon’—developed during 2007–2008 within practice-led PhD enquiry conducted in collaboration with the Nerve Centre, a third-sector media education organisation. The article goes on to critically examine the processes involved in practically realising, and creatively and theoretically reconciling, community-engaged digital production in a particular socio-political context of academic-community collaboration

    Produção de grãos de milho e soja submetidos a diferentes doses e modos de incorporação de calcário.

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    Os solos de Rondônia caracterizam-se por apresentar baixo pH, baixos teores de matéria orgânica, Ca e Mg trocáveis, baixo índice de saturação de bases, e relativamente elevados teores de alumínio trocáveis, o que diminui consideravelmente o potencial de rendimento das culturas. Este trabalho teve por objetivo avaliar a eficiência da calagem aplicada com diferentes doses e modos de incorporação ou mantido em superfície no solo. O experimento foi instalado em janeiro de 2009 em um Latossolo, em esquema fatorial 3 x 3 com 3 repetições, sendo, com doses de calcário (zero de calcário e doses para elevar a saturação de bases a 50 e 70%) mantido em superfície e incorporado em sistema convencional e mínimo de cultivo; foi cultivado soja e milho na safra 2010/11.A adubação e os demais tratos culturais foram feitos conforme recomendações específicas; após as avaliações de rendimento os dados foram submetidos a análise de variância. Não se verificou diferença nos efeitos isolados ou da interação dos tratamentos de doses e modos de incorporação nos rendimentos de grãos

    IRAS sky survey atlas: Explanatory supplement

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    This Explanatory Supplement accompanies the IRAS Sky Survey Atlas (ISSA) and the ISSA Reject Set. The first ISSA release in 1991 covers completely the high ecliptic latitude sky, absolute value of beta is greater than 50 deg, with some coverage down to the absolute value of beta approx. equal to 40 deg. The second ISSA release in 1992 covers ecliptic latitudes of 50 deg greater than the absolute value of beta greater than 20 deg, with some coverage down to the absolute value of beta approx. equal to 13 deg. The remaining fields covering latitudes within 20 deg of the ecliptic plane are of reduced quality compared to the rest of the ISSA fields and therefore are released as a separate IPAC product, the ISSA Reject Set. The reduced quality is due to contamination by zodiacal emission residuals. Special care should be taken when using the ISSA Reject images. In addition to information on the ISSA images, some information is provided in this Explanatory Supplement on the IRAS Zodiacal History File (ZOHF), Version 3.0, which was described in the December 1988 release memo. The data described in this Supplement are available at the National Space Science Data Center (NSSDC) at the Goddard Space Flight Center. The interested reader is referred to the NSSDC for access to the IRAS Sky Survey Atlas (ISSA)

    Efficacy of RTS,S malaria vaccines: individual-participant pooled analysis of phase 2 data.

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    BACKGROUND: The efficacy of RTS,S/AS01 as a vaccine for malaria is being tested in a phase 3 clinical trial. Early results show significant, albeit partial, protection against clinical malaria and severe malaria. To ascertain variations in vaccine efficacy according to covariates such as transmission intensity, choice of adjuvant, age at vaccination, and bednet use, we did an individual-participant pooled analysis of phase 2 clinical data. METHODS: We analysed data from 11 different sites in Africa, including 4453 participants. We measured heterogeneity in vaccine efficacy by estimating the interactions between covariates and vaccination in pooled multivariable Cox regression and Poisson regression analyses. Endpoints for measurement of vaccine efficacy were infection, clinical malaria, severe malaria, and death. We defined transmission intensity levels according to the estimated local parasite prevalence in children aged 2-10 years (PrP₂₋₁₀), ranging from 5% to 80%. Choice of adjuvant was either AS01 or AS02. FINDINGS: Vaccine efficacy against all episodes of clinical malaria varied by transmission intensity (p=0·001). At low transmission (PrP₂₋₁₀ 10%) vaccine efficacy was 60% (95% CI 54 to 67), at moderate transmission (PrP₂₋₁₀ 20%) it was 41% (21 to 57), and at high transmission (PrP₂₋₁₀ 70%) the efficacy was 4% (-10 to 22). Vaccine efficacy also varied by adjuvant choice (p<0·0001)--eg, at low transmission (PrP₂₋₁₀ 10%), efficacy varied from 60% (95% CI 54 to 67) for AS01 to 47% (14 to 75) for AS02. Variations in efficacy by age at vaccination were of borderline significance (p=0·038), and bednet use and sex were not significant covariates. Vaccine efficacy (pooled across adjuvant choice and transmission intensity) varied significantly (p<0·0001) according to time since vaccination, from 36% efficacy (95% CI 24 to 45) at time of vaccination to 0% (-38 to 38) after 3 years. INTERPRETATION: Vaccine efficacy against clinical disease was of limited duration and was not detectable 3 years after vaccination. Furthermore, efficacy fell with increasing transmission intensity. Outcomes after vaccination cannot be gauged accurately on the basis of one pooled efficacy figure. However, predictions of public-health outcomes of vaccination will need to take account of variations in efficacy by transmission intensity and by time since vaccination. FUNDING: Medical Research Council (UK); Bill & Melinda Gates Foundation Vaccine Modelling Initiative; Wellcome Trust

    Knockout of proton-neutron pairs from 16^{16}O with electromagnetic probes

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    After recent improvements to the Pavia model of two-nucleon knockout from 16^{16}O with electromagnetic probes the calculated cross sections are compared to experimental data from such reactions. Comparison with data from a measurement of the 16^{16}O(e,e'pn) reaction show much better agreement between experiment and theory than was previously observed. In a comparison with recent data from a measurement of the 16^{16}O(γ\gamma,pn) reaction the model over-predicts the measured cross section at low missing momentum.Comment: 6 pages, 5 figure

    A model for two-proton emission induced by electron scattering

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    A model to study two-proton emission processes induced by electron scattering is developed. The process is induced by one-body electromagnetic operators acting together with short-range correlations, and by two-body Δ\Delta currents. The model includes all the diagrams containing a single correlation function. A test of the sensitivity of the model to the various theoretical inputs is done. An investigation of the relevance of the Δ\Delta currents is done by changing the final state angular momentum, excitation energy and momentum transfer. The sensitivity of the cross section to the details of the correlation function is studied by using realistic and schematic correlations. Results for 12^{12}C, 16^{16}O and 40^{40}Ca nuclei are presented.Comment: 30 pages, 18 figures, 3 table

    Деформационное упрочнение начально-изотропных металлов при деформировании по траекториям малой кривизны

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    На примере стали мартенситного класса исследованы закономерности деформационного упрочнения при нагружении по траекториям, имеющим вид двухзвенных ломаных, которым соответствуют траектории деформирования малой кривизны. Показано, что поверхность нагружения, разделяющая области упругого и упругопластического деформирования, смещается в направлении вектора, который соединяет центр поверхности нагружения и изображающую точку на траектории нагружения, при этом не изменяется форма ее фронтальной части. Зависимость величины смещения центра поверхности нагружения от интенсивности накопленных пластических деформаций описывается кривой, инвариантной к виду траектории нагружения.На прикладі сталі мартенситного класу досліджено закономірності деформаційного зміцнення при навантаженні по траєкторіях, що мають вигляд дволанкових ламаних, яким відповідають траєкторії деформування малої кривини. Показано, що поверхня навантаження, яка розділяє області пружного та пружнопластичного деформування, зміщується у напрямку вектора, який з ’єднує центр поверхні навантаження та відображуючу точку на траєкторії навантаження, при цьому форма фронтальної частини не змінюється. Залежність величини зміщення центра поверхні навантаження від інтенсивності накопичених пластичних деформацій описується кривою, яка є інваріантною відносно траєкторії навантаження.By the example of martensitic steel we study regularities of strain hardening under loading along two-section broken lines corresponding to slightly curved strain paths. It is shown that the loading surface separating domains of elastic and elastoplastic strains (yield surface) is displaced in the direction of a vector connecting the surface center with the loading trajectory image point, while the shape of its frontal part remains unchanged. The yield surface center displacement versus the intensity of accumulated plastic strains is described by a curve invariant to the loading trajectory
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