958 resultados para PARTITION
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The goal of this study is to better understand the genetic basis of Reading Disability (RD) and Attention Deficit Hyperactivity Disorder (ADHD) by examining molecular G x E interactions with parental education for each disorder. Research indicates that despite sharing genetic risk factors, RD and ADHD are influenced by different types of G x E interactions with parental education - a diathesis stress interaction in the case of ADHD and a bioecological interaction in RD. In order to resolve this apparent paradox, we conducted a preliminary study using behavioral genetic methods to test for G x E interactions in RD and the inattentive subtype of ADHD (ADHD-I) in the same sample of monozygotic and dizygotic Colorado Learning Disabilities Research Center same-sex twin pairs (DeFries et al., 1997), and our findings were consistent with the literature. We posited a genetic hypothesis for this opposite pattern of interactions, which suggests that only genes specific to each disorder enter into these opposite interactions, not the shared genes underlying their comorbidity. This study sought to further investigate this paradox using molecular genetics methods. We examined multiple candidate genes identified for RD or related language phenotypes and those identified for ADHD for G x E interactions with parental education. The specific aims of this study were as follows: 1) partition known risk alleles for RD and/or related language phenotypes and ADHD-I into those which are pleiotropic and non-pleiotropic by testing each risk allele for association with both RD and ADHD-I, 2) explore the main effects of parental education on both RD and ADHD-I, 3) address G-E correlations, and 4) conduct exploratory G x E interaction analyses in order to test the genetic hypothesis. Analyses suggested a number of pleiotropic genes that influence both RD and ADHD; however, results did not remain after correcting for multiple comparisons. Although exploratory G x E interaction findings were not significant after multiple comparison correction, results suggested a G x E interaction in the bioecological direction with KIAA0319, parental education, and ADHD-I. Given the limited power in the current study, replication of these findings with larger samples is necessary.
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Um método rápido utilizando cromatografia liquida (LC) foi desenvolvido para determinação simultânea de 7 pesticidas piretróides (bifentrina, cipermetrina, fenpropatrina, fenvalerato, permetrina, lambda-cialotrina, e deltametrina). Os resíduos são extraídos com acetona e a partição realizada de acordo com o método multi-resíduos DFG-S19, substituindo diclorometano por acetato de etila/ciclohexano (1+1) e purificação usando cromatografia de permeação a gel com uma coluna Biobeads SX3 e acetato de etila/ciclohexano (1+1) como eluente. A separação por LC é realizada com uma coluna LiChrospher 100 RP-18 e acetonitrila/água (8+2) como fase móvel. Os pesticidas são detectados em 212nm. As recuperações dos 7 pesticidas piretróides em amostras de feijão fortificadas em 0,010; 0,100; e 1,000 mg/kg ficaram entre 71-105%. A diferença particular deste método é o limite de quantificação, os quais ficaram entre 0,004-0,011 mg/kg, abaixo de muitos outros métodos de LC descritos na literatura. A cromatografia a gás (GC) com detector de captura de elétrons é mais sensível que a LC, mas o método com LC facilita a identificação dos picos. A GC apresenta muitos picos enquanto a LC apresenta apenas um para a maioria dos piretróides. A análise com LC é uma boa alternativa para a determinação de resíduos de piretróides em feijão. Durante o ano de 2005, um total de 48 amostras de feijão comercializadas na cidade de São Paulo, foram analisadas. Nenhum resíduo de pesticida piretróide foi detectado nas amostras.
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A siderurgia vem sofrendo transformações que buscam inovação e matérias-primas alternativas. Dentro deste contexto, o uso de resíduos industriais para a formação de escórias sintéticas é tido como alternativa na busca de novos materiais e rotas de reaproveitamento de resíduos. Portanto, este trabalho teve como objetivo estudar o uso de escórias sintéticas na etapa de dessulfuração do ferro-gusa, aço e ferro fundido. Assim como, propor a utilização da sodalita e da alumina em substituição à fluorita e o resíduo de mármore em substituição à cal convencional. Inicialmente, o resíduo foi caracterizado utilizando as seguintes técnicas: análise química, análise granulométrica, área de superfície específica, difração de raios-X, microscopia eletrônica de varredura (MEV) e análise de espectroscopia por energia dispersiva (EDS). Os resultados da caracterização mostraram que aproximadamente 90% das partículas do resíduo de mármore estão abaixo de 100m e sua área superficial foi de 0,24m²/g. Através da difração de raios-X foi observado que o resíduo é composto por CaCO3, MgCO3 e SiO2. Na sequência, foram feitas simulações com o software Thermo-Calc para obter dados termodinâmicos das fases presentes nas misturas e compará-los com os resultados experimentais. Além disso, também foram calculados dados de capacidade de sulfeto (Cs), partição de enxofre (Ls) e basicidade ótica () das misturas iniciais. Posteriormente, foram realizados os ensaios experimentais em escala laboratorial para ferro-gusa, ferro fundido e aço, respectivamente nas temperaturas de 1400°C, 1550°C e 1600°C. Nos ensaios de dessulfuração do aço e do ferro-gusa, utilizou-se um rotor de alumina com o objetivo de favorecer a agitação no metal e aumentar a remoção de enxofre. Na etapa de dessulfuração do ferro-gusa, constatou-se que a fase sólida de CaO é a responsável pela remoção de enxofre e que a presença das fases silicato tricálcio e aluminato tricálcio (3CaO.SiO2 e 3CaO.Al2O3) limitam a reação, sendo maiores suas concentrações nas escórias que utilizaram o resíduo de mármore e sodalita, devido a presença de SiO2 e Al2O3 nestas matérias-primas. Já para o aço e o ferro fundido, que foram estudados com escórias à base de CaO e Al2O3, observou-se que o aumento da fase líquida favoreceu a dessulfuração. Verificou-se que a dessulfuração no ferro fundido foi por escória de topo e no aço por um processo misto, onde a fase líquida e fase sólida participaram da dessulfuração.
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O ouro, assim como outros bens minerais, é uma commodity, ou seja, um produto não diferenciado, com preço determinado pelo mercado internacional, sem a interferência de seus produtores. Diante desse cenário, associado à exaustão dos depósitos minerais de maiores teores, as mineradoras vêm buscando melhores formas de aproveitamento de matérias-primas minerais mais complexas quanto à extração e ao beneficiamento. Os retornos financeiros são obtidos no estrito controle da produção com redução de custos e mitigação de perdas nas operações unitárias. A caracterização tecnológica está inserida como uma abordagem multidisciplinar e fundamental para o melhor aproveitamento dos bens minerais. Possibilita um maior conhecimento do minério e das associações minerais presentes, que auxiliará no desenvolvimento das alternativas de explotação e na otimização do processo em funcionamento. Dentre os procedimentos de caracterização das associações minerais mais acurados citam-se os sistemas automatizados de análise de imagens adquiridas por microscopia eletrônica de varredura. Permitem a avaliação qualitativa ou quantitativa de grande número de partículas quanto à composição química e mineral, partição de elementos nos minerais presentes, formas de associações e liberação entre os minerais. Este estudo se concentra na caracterização de quatro amostras mineralizadas a ouro, de diferentes regiões do Brasil, pela análise automatizada de imagens e por métodos laboratoriais de separações minerais e extração hidrometalúrgica do ouro. A combinação de procedimentos laboratoriais com a análise de imagens permitiu confrontar os resultados das recuperações potenciais, fornecendo subsídios para abordagens de processo, para obtenção da máxima recuperação do ouro e para diagnosticar as características interferentes nesses processos.
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In this paper we describe an hybrid algorithm for an even number of processors based on an algorithm for two processors and the Overlapping Partition Method for tridiagonal systems. Moreover, we compare this hybrid method with the Partition Wang’s method in a BSP computer. Finally, we compare the theoretical computation cost of both methods for a Cray T3D computer, using the cost model that BSP model provides.
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The delineation of functional economic areas, or market areas, is a problem of high practical relevance, since the delineation of functional sets such as economic areas in the US, Travel-to-Work Areas in the United Kingdom, and their counterparts in other OECD countries are the basis of many statistical operations and policy making decisions at local level. This is a combinatorial optimisation problem defined as the partition of a given set of indivisible spatial units (covering a territory) into regions characterised by being (a) self-contained and (b) cohesive, in terms of spatial interaction data (flows, relationships). Usually, each region must reach a minimum size and self-containment level, and must be continuous. Although these optimisation problems have been typically solved through greedy methods, a recent strand of the literature in this field has been concerned with the use of evolutionary algorithms with ad hoc operators. Although these algorithms have proved to be successful in improving the results of some of the more widely applied official procedures, they are so time consuming that cannot be applied directly to solve real-world problems. In this paper we propose a new set of group-based mutation operators, featuring general operations over disjoint groups, tailored to ensure that all the constraints are respected during the operation to improve efficiency. A comparative analysis of our results with those from previous approaches shows that the proposed algorithm systematically improves them in terms of both quality and processing time, something of crucial relevance since it allows dealing with most large, real-world problems in reasonable time.
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We give a partition of the critical strip, associated with each partial sum 1 + 2z + ... + nz of the Riemann zeta function for Re z < −1, formed by infinitely many rectangles for which a formula allows us to count the number of its zeros inside each of them with an error, at most, of two zeros. A generalization of this formula is also given to a large class of almost-periodic functions with bounded spectrum.
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Immobilization of enzymes may produce alterations in their observed activity, specificity or selectivity. Although in many cases an impoverishment of the enzyme properties is observed upon immobilization (caused by the distortion of the enzyme due to the interaction with the support) in some instances such properties may be enhanced by this immobilization. These alterations in enzyme properties are sometimes associated with changes in the enzyme structure. Occasionally, these variations will be positive. For example, they may be related to the stabilization of a hyperactivated form of the enzyme, like in the case of lipases immobilized on hydrophobic supports via interfacial activation. In some other instances, these improvements will be just a consequence of random modifications in the enzyme properties that in some reactions will be positive while in others may be negative. For this reason, the preparation of a library of biocatalysts as broad as possible may be a key turning point to find an immobilized biocatalyst with improved properties when compared to the free enzyme. Immobilized enzymes will be dispersed on the support surface and aggregation will no longer be possible, while the free enzyme may suffer aggregation, which greatly decreases enzyme activity. Moreover, enzyme rigidification may lead to preservation of the enzyme properties under drastic conditions in which the enzyme tends to become distorted thus decreasing its activity. Furthermore, immobilization of enzymes on a support, mainly on a porous support, may in many cases also have a positive impact on the observed enzyme behavior, not really related to structural changes. For example, the promotion of diffusional problems (e.g., pH gradients, substrate or product gradients), partition (towards or away from the enzyme environment, for substrate or products), or the blocking of some areas (e.g., reducing inhibitions) may greatly improve enzyme performance. Thus, in this tutorial review, we will try to list and explain some of the main reasons that may produce an improvement in enzyme activity, specificity or selectivity, either real or apparent, due to immobilization.
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Hydrogen peroxide is a substrate or side-product in many enzyme-catalyzed reactions. For example, it is a side-product of oxidases, resulting from the re-oxidation of FAD with molecular oxygen, and it is a substrate for peroxidases and other enzymes. However, hydrogen peroxide is able to chemically modify the peptide core of the enzymes it interacts with, and also to produce the oxidation of some cofactors and prostetic groups (e.g., the hemo group). Thus, the development of strategies that may permit to increase the stability of enzymes in the presence of this deleterious reagent is an interesting target. This enhancement in enzyme stability has been attempted following almost all available strategies: site-directed mutagenesis (eliminating the most reactive moieties), medium engineering (using stabilizers), immobilization and chemical modification (trying to generate hydrophobic environments surrounding the enzyme, to confer higher rigidity to the protein or to generate oxidation-resistant groups), or the use of systems capable of decomposing hydrogen peroxide under very mild conditions. If hydrogen peroxide is just a side-product, its immediate removal has been reported to be the best solution. In some cases, when hydrogen peroxide is the substrate and its decomposition is not a sensible solution, researchers coupled one enzyme generating hydrogen peroxide “in situ” to the target enzyme resulting in a continuous supply of this reagent at low concentrations thus preventing enzyme inactivation. This review will focus on the general role of hydrogen peroxide in biocatalysis, the main mechanisms of enzyme inactivation produced by this reactive and the different strategies used to prevent enzyme inactivation caused by this “dangerous liaison”.
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A partir de un cabreve de 1416 conservado en el Archivo del Reino de Valencia hemos pretendido reconstruir cuál fue el desarrollo del lugar de Ondara, en el norte de la actual provincia de Alicante, en particular la renta percibida por el señor, el duque de Gandía. Ondara tenía una población de mayoría mudéjar, aunque también vivían en la localidad cristianos. De esta renta era la partición de frutos de los mudéjares y los cristianos, con sus 4.000 sueldos, la que proporcionaba los mayores ingresos en las arcas señoriales, es decir, el gravamen sobre la actividad económica de la localidad, seguida por los arrendamientos y el besante. Además de la agricultura había una actividad artesana en torno a la cantarería, la fabricación de jabón y el tinte. Se completa el estudio con unas normas municipales del año 1410 y la prosopografía de los vecinos.
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de J. Barbier et M. Carré ; musique de Ch. Gounod ; partition chant et piano arrangée par H. Salomon.
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Commonplace book containing excerpts on religion, philosophy, geometry and other subjects; with two fold-out tables, one concerning the "partition of sciences" and the other "grand divisions of Europe."
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This layer is a georeferenced raster image of the historic paper map entitled: The peninsula of India : from the Kistnah River to Cape Comorin : exhibiting the partition of the territories of the late Tippoo Sultaun, according to the treaty of 1792, made by the Marquis Cornwallis, and that of 1799, made by the Marquis Wellesley by J. Rennell ; writing b W. Harrison. It was published by J. Rennell : sold by G. Nicol in 1800. Scale [ca. 1:2,300,000]. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Kalianpur 1975 India Zone III projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, territorial, administrative and colonial boundaries, shoreline features, and more. Relief shown by hachures.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.
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Recent research works have concluded that corn cob may have interesting material properties, in particular, lightness, and thermal and sound insulation abilities. In this research work, corn cob is proposed as an alternative sustainable aggregate for lightweight concrete masonry unit (CMU) manufacturing. The corn cob requires to be granulated previously in order to obtain adequate particle size grade. Subsequently, the particles are wrapped in a cement paste with the purpose of reducing their water abortion and adherent capacities. CMU are current applied in the building of partition walls. The main goal of this research work consists on studying the fire behaviour of partition walls built with CMU of processed corn cob granulate (CMU-PCC).
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Bosnia and Kosovo are the only two members of the EU enlargement zone that have never tried to apply for EU membership, given that both are too far from complying with the required minimum standards. But besides lacking basic capacities, these two potential candidates share another common feature: both are limited, to different degrees, in their national sovereignty. This lack of sovereignty not only limits the capacity of the potential candidates to negotiate or to enter into agreements with the EU; it also undermines their readiness to undertake serious reforms. The EU tries to dodge the political blockades that are the root cause of the problem by focusing on the technical issues; this might provide a temporary relief but cannot substitute a realistic accession perspective, which is currently absent. However, without this perspective, the EU’s ‘normative power’ in these countries will continue to erode – which bears the risk that both Kosovo and Bosnia will, in the end, try to solve existing problems through unilateral measures, such as partition. Given its lack of ability to provide alternatives, the EU has to realistically consider such outcomes and think about the possible consequences.