712 resultados para Li_8SiN_4-Li_3N-BN


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Estudio de la forma epidemiológica de los trastornos de la conducta alimentaria en la población escolarizada de la Comunidad de Madrid. Se ha estudiado la prevalencia de los Trastornos de la Conducta Alimentaria (TCA) en una muestra de 1.543 adolescentes y jóvenes de 12 a 21 años de ambos sexos, que cursaban en el curso académico 2001-2002: Educación Secundaria Obligatoria (ESO), Bachillerato-LOGSE y Primero de Universidad en la Comunidad Autónoma de Madrid (CAM). Se ha empleado un muestreo aleatorio por conglomerados, eligiendo los centros al azar en función de dos variables: Madrid Capital vs. municipios de la CAM y centro público, concertado o privado. Fueron excluidos los centros de educación especial. El estudio epidemiológico consistió en dos fases, una primera de barrido, en la que se administró una ficha de datos sociodemográficos generales junto con dos instrumentos de screening: Eating Attitudes Test (EAT-40) de Garner y Garfinkel (1979); y la segunda, de adaptación al castellano de Eating Disorder Examination-Questionnaire (EDE-Q) de Fairburn y Beglin (1994). Todos los sujetos (n=349) que igualaron o superaron el punto de corte 20 en el EAT-40 o que cumplieron criterios diagnósticos DSM-IV-TR (APA, 2000) en el EDE-Q fueron seleccionados para una segunda fase de entrevista, junto con una muestra aleatoria de probables controles (n=270). La entrevista utilizada fue Eating Disorder Examination (EDE). El 3,3 por ciento de la muestra: 51 sujetos (4 varones y 47 mujeres) cumplieron criterios diagnósticos DSM-IV-TR de TCA en la entrevista EDE. La tasa de prevalencia de TCA fue de 5,13 por ciento en mujeres (2,73 por ciento trastornos alimentarios no especificados (TCNAE); 2,29 por ciento bulimia nerviosa (BN) y 0,11 anorexia nerviosa (AN)) y de 0,64 por ciento en varones (0,48 por ciento TCANE; 0,16 BN y 0,00 AN). Las variables sociodemográficas que han mostrado tener asociación con el padecimiento de TCA en la muestra fueron: sexo, edad, número de hermanos, familias monoparentales y fallecimiento de algunos de los padres; siendo superior en: mujeres (Odds Ratio (OR) = 8,4), mayores de 19 años (OR = 4) hijos únicos (OR = 2), alumnos que viven sólo con uno de los padres (OR = 4) y aquellos cuyos padre o madre ha fallecido (OR = 6).

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I.-Descubrir la incidencia y la asociación entre los Trastornos de la Conducta Alimentaria y el consumo de drogas, en los dispositivos asistenciales de Salud Mental del Servicio Navarro de Salud. II.-Identificar las particularidades que presentan las pacientes afectadas desde el punto de vista clínico y psicosocial, así como las implicaciones clínicas derivadas de la asociación de los TCA y el consumo de sustancias. Noventa pacientes mujeres que solicitan tratamiento por padecer TCA como primer diagnóstico en el Centro de Salud Mental de Ermitagaña de Pamplona del Servicio Navarro de Salud. No existió selección previa. Las pacientes eran citadas a consulta según disponibilidad de los profesionales facultativos del Centro de Salud. A todas ellas se les pasa un Protocolo en el contexto de la correspondiente exploración clínica. El equipo investigador diseña y elabora el protocolo en el que se recogen diferentes variables desde una perspectiva bio-psico-social de los TCA. Consta de cinco bloques temáticos con sus apartados: I.-Datos sociodemográficos y de localización: el perfil sociodemográfico del paciente y la ficha personal del mismo. II.-Historia de la enfermedad: información subjetiva de la propia paciente sobre la edad de comienzo del trastorno alimenticio y sobre los acontecimientos previos a los TCA. III.-Consumo de sustancias. IV.-Estado actual de la enfermedad. V.-Motivación, Diagnóstico y Tratamiento: escala de dimensiones causales de Dan Russell. Esta información diagnóstica se completa con el estudio de las Medidas antropométricas y pruebas de laboratorio. Cuestionarios de evaluación psicopatológica: I.-El Inventario de Depresión de BECK (BDI): para evaluar la intensidad de los síntomas depresivos. II.-El Cuestionario de ansiedad estado/rasgo (STAI): la autoevaluación de dos conceptos independientes de la ansiedad, la ansiedad como estado y la ansiedad como rasgo. III.-El Inventario clínico multiaxial de Millon-II (MCMI-II): instrumento de evaluación clínica para el estudio de personalidad. Cuestionarios de evaluación de los TCA: I.-Eating Attitudes Test (EAT-40): para la evaluación de las actitudes y del comportamiento en la anorexia. II.-Body Attitude test (BAT): para medir la actitud negativa hacia el cuerpo. III.-Inventario para el estudio de la Bulimia, Edimburgo (BITE): permite identificar la presencia de síntomas bulímicos y su intensidad. IV.-Eating Disorder Inventory (EDI-2): cuestionario diseñado para la evaluación de los síntomas de relevancia clínica asociados a la AN y BN. Programa estadístico SPSS para Windows. I.-La prevalencia del consumo de sustancias-tanto legales como ilegales-manifiesta una mayor tendencia a la asociación con las pacientes diagnosticadas de AN y BN. II.-El tipo de droga consumida tiende a presentarse asociada con los padecimientos de AN o de BN. Se observa cierta relación entre el tipo de droga y el consumo, con el hecho de que el síndrome sea completo o parcial. III.-La edad media de iniciación en el consumo de sustancias, resultaba más precoz entre las pacientes bulímicas que respecto a las anoréxicas. IV.-La presencia simultánea de TCA y de consumo de sustancias era superior entre aquellas pacientes que presentaron factores sociofamiliares desfavorables y/o estresantes. V.-La prevalencia de síntomas físicos surgió con mayor frecuencia en aquellas pacientes diagnosticadas de TCA que, además, solían consumir sustancias. VI.-Las alteraciones psicopatológicas eran más altas en los casos que había concurrencia de TCA y de consumo de drogas, que en aquéllos que poseían un diagnóstico único de TCA.

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Two tridentate Schiff bases, HL1(6-amino-3-methyl-1-phenyl-4-azahex-2-en-1-one), and HL2 (6-atnino-3,6-dimethyl-1-phenyl-4-azahex-2-en-1-one) on reaction with Cu(II) perchlorate in the presence of triethyl amine yielded two new trinuclear copper(II) complexes, [(CuL1)(3)(mu(3)-OH)](ClO4)(2) (1) and [(CuL2)(3)(mu(3)-OH)](ClO4)(2) center dot 0.75H(2)O (2), whereas another tridentate ligand HL3 (7-amino-3-methyl-1-phenyl-4-azahept-2-en-1-one) underwent hydrolysis under the same reaction conditions to result in the formation of a mononuclear complex, [Cu(bn)(pn)ClO4] (3) [where bn = 1-benzoylacetonate and pn = 1,3-propanediamine]. All three complexes have been characterized by X-ray crystallography. For both 1 and 2 the cationic part is trinuclear with a [Cu3OH] core held by three carbonyl oxygen bridges between each pair of copper(II) atoms. The structure of 3 is a monomer with a chelating 1,3-propanediamine and a benzoyl acetone moiety. Magnetic measurements of I and 2 have been performed in the 2-300 K temperature range. The experimental data could be satisfactorily reproduced by using an isotropic exchange model, H = -J(S1S2 + S2S3 + S1S3), yielding as best fit parameters: J = -25.6 cm(-1), g = 2.21 for 1 and J = 11.2 cm(-1), g = 2.10 for 2. The EPR spectra at low temperature could be indicative of spin frustration in complex 1. (C) 2006 Elsevier Ltd. All rights reserved.

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Two Schiff bases, HL1 and HL2 have been prepared by the condensation of N-methyl-1,3-propanediamine (mpn) with salicylaldehyde and 1-benzoylacetone (Hbn) respectively. HL1 on reaction with Cu(ClO4)(2)center dot 6H(2)O in methanol produced a trinuclear Cu-II complex, [(CuL1)(3)(mu(3)-OH)](ClO4)(2)center dot H2O center dot 0.5CH(2)Cl(2) (1) but HL2 underwent hydrolysis under similar reaction conditions to result in a ternary Cu-II complex, [Cu(bn)(mpn)ClO4]. Both complexes have been characterised by single-crystal X-ray analyses, IR and UV-Vis spectroscopy and electrochemical studies. The partial cubane core [Cu3O4] of 1 consists of a central mu(3)-OH and three peripheral phenoxo bridges from the Schiff base. All three copper atoms of the trinuclear unit are five-coordinate with a distorted square-pyramidal geometry. The ternary complex 2 is mononuclear with the square-pyramidal Cu-II coordinated by a chelating bidentate diamine (mpn) and a benzoylacetonate (bn) moiety in the equatorial plane and one of the oxygen atoms of perchlorate in an axial position. The results show that the Schiff base (HL2) derived from 1-benzoylacetone is more prone to hydrolysis than that from salicylaldehyde (HL1). Magnetic measurements of 1 have been performed in the 1.8-300 K temperature range. The experimental data clearly indicate antiferromagnetism in the complex. The best-fit parameters for complex 1 are g = 2.18(1) and J = -15.4(2) cm(-1).

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Private sector commercial property represents some #400 bn, or 34% of total UK business assets and is a vital fabric for housing commercial enterprise. Yet social and economic forces for change, linked with new technology, are making owners and occupiers question the very nature and purpose of property and real estate.

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In this paper we study Dirichlet convolution with a given arithmetical function f as a linear mapping 'f that sends a sequence (an) to (bn) where bn = Pdjn f(d)an=d. We investigate when this is a bounded operator on l2 and ¯nd the operator norm. Of particular interest is the case f(n) = n¡® for its connection to the Riemann zeta function on the line 1, 'f is bounded with k'f k = ³(®). For the unbounded case, we show that 'f : M2 ! M2 where M2 is the subset of l2 of multiplicative sequences, for many f 2 M2. Consequently, we study the `quasi'-norm sup kak = T a 2M2 k'fak kak for large T, which measures the `size' of 'f on M2. For the f(n) = n¡® case, we show this quasi-norm has a striking resemblance to the conjectured maximal order of j³(® + iT )j for ® > 12 .

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The complexity of current and emerging high performance architectures provides users with options about how best to use the available resources, but makes predicting performance challenging. In this work a benchmark-driven performance modelling approach is outlined that is appro- priate for modern multicore architectures. The approach is demonstrated by constructing a model of a simple shallow water code on a Cray XE6 system, from application-specific benchmarks that illustrate precisely how architectural char- acteristics impact performance. The model is found to recre- ate observed scaling behaviour up to 16K cores, and used to predict optimal rank-core affinity strategies, exemplifying the type of problem such a model can be used for.

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Modification of graphene to open a robust gap in its electronic spectrum is essential for its use in field effect transistors and photochemistry applications. Inspired by recent experimental success in the preparation of homogeneous alloys of graphene and boron nitride (BN), we consider here engineering the electronic structure and bandgap of C2xB1−xN1−x alloys via both compositional and configurational modification. We start from the BN end-member, which already has a large bandgap, and then show that (a) the bandgap can in principle be reduced to about 2 eV with moderate substitution of C (x < 0.25); and (b) the electronic structure of C2xB1−xN1−x can be further tuned not only with composition x, but also with the configuration adopted by C substituents in the BN matrix. Our analysis, based on accurate screened hybrid functional calculations, provides a clear understanding of the correlation found between the bandgap and the level of aggregation of C atoms: the bandgap decreases most when the C atoms are maximally isolated, and increases with aggregation of C atoms due to the formation of bonding and anti-bonding bands associated with hybridization of occupied and empty defect states. We determine the location of valence and conduction band edges relative to vacuum and discuss the implications on the potential use of 2D C2xB1−xN1−x alloys in photocatalytic applications. Finally, we assess the thermodynamic limitations on the formation of these alloys using a cluster expansion model derived from first-principles.

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Eating attitudes are defined as beliefs. thoughts, feelings and behaviors towards food. Bulimia nervosa (BN) is ail eating disorder, in which the eating, attitudes are Seriously disturbed. Studies that evaluated nutritional aspects of BN focus mainly oil food intake, dietary restriction and binge eating. while the follow-up Studies evaluate mainly clinical symptoms. The objective of this study was to evaluate eating attitudes of patients with BN. during and after cognitive-behavioral intervention. Thirty nine (39) BN female patients received cognitive behavioral treatment with a Multidisciplinary team and had eating attitudes assessed by a questionnaire developed for this research. Frequencies of the attitudes assessed were compared at baseline. after 12 weeks and 24 weeks of treatment. After treatment, patients had less distorted beliefs about food, less guilty after eating ""forbidden"" foods and they felt more tranquil while caring outside home. Other negative behaviors, as dietary restriction, the desire of not cat, being angry when feeling hungry and using the food to relive stress. persisted. Eating attitudes of patients with BN are hard to be changed in a short-term. More attention to this disease`s component and new approaches to treatment are needed in order to have a better recovery.

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Two indigenous ceramics fragments, one from Lagoa Queimada (LQ) and another from Barra dos Negros (BN), both sites located on Bahia state (Brazil), were dated by termoluminescence (TL) method. Each fragment was physically prepared and divided into two fractions, one was used for TL measurement and the other for annual dose determination. The TL fraction was chemically treated, divided in sub samples and irradiated with several doses. The plot extrapolation from TL intensities as function of radiation dose enabled the determination of the accumulated dose (D(ac)), 3.99 Gy and 1.88 Gy for LQ and BN, respectively. The annual dose was obtained through the uranium, thorium and potassium determination by ICP-MS. The annual doses (D(an)) obtained were 2.86 and 2.26 mGy/year. The estimated ages were similar to 1375 and 709 y for BN and LQ ceramics, respectively. The ages agreed with the archaeologists` estimation for the Aratu and Tupi tradition periods, respectively.

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In 1983, Chvatal, Trotter and the two senior authors proved that for any Delta there exists a constant B such that, for any n, any 2-colouring of the edges of the complete graph K(N) with N >= Bn vertices yields a monochromatic copy of any graph H that has n vertices and maximum degree Delta. We prove that the complete graph may be replaced by a sparser graph G that has N vertices and O(N(2-1/Delta)log(1/Delta)N) edges, with N = [B`n] for some constant B` that depends only on Delta. Consequently, the so-called size-Ramsey number of any H with n vertices and maximum degree Delta is O(n(2-1/Delta)log(1/Delta)n) Our approach is based on random graphs; in fact, we show that the classical Erdos-Renyi random graph with the numerical parameters above satisfies a stronger partition property with high probability, namely, that any 2-colouring of its edges contains a monochromatic universal graph for the class of graphs on n vertices and maximum degree Delta. The main tool in our proof is the regularity method, adapted to a suitable sparse setting. The novel ingredient developed here is an embedding strategy that allows one to embed bounded degree graphs of linear order in certain pseudorandom graphs. Crucial to our proof is the fact that regularity is typically inherited at a scale that is much finer than the scale at which it is assumed. (C) 2011 Elsevier Inc. All rights reserved.

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Consider the following problem: Forgiven graphs G and F(1),..., F(k), find a coloring of the edges of G with k colors such that G does not contain F; in color i. Rodl and Rucinski studied this problem for the random graph G,,, in the symmetric case when k is fixed and F(1) = ... = F(k) = F. They proved that such a coloring exists asymptotically almost surely (a.a.s.) provided that p <= bn(-beta) for some constants b = b(F,k) and beta = beta(F). This result is essentially best possible because for p >= Bn(-beta), where B = B(F, k) is a large constant, such an edge-coloring does not exist. Kohayakawa and Kreuter conjectured a threshold function n(-beta(F1,..., Fk)) for arbitrary F(1), ..., F(k). In this article we address the case when F(1),..., F(k) are cliques of different sizes and propose an algorithm that a.a.s. finds a valid k-edge-coloring of G(n,p) with p <= bn(-beta) for some constant b = b(F(1),..., F(k)), where beta = beta(F(1),..., F(k)) as conjectured. With a few exceptions, this algorithm also works in the general symmetric case. We also show that there exists a constant B = B(F,,..., Fk) such that for p >= Bn(-beta) the random graph G(n,p) a.a.s. does not have a valid k-edge-coloring provided the so-called KLR-conjecture holds. (C) 2008 Wiley Periodicals, Inc. Random Struct. Alg., 34, 419-453, 2009

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o presente trabalho é um estudo exploratório a respeito da síntese de filmes de diamante via deposiçãoquímica a vapor (CVD) sobre alguns substratos cerâmicos: diboreto de titânio (TiB2), ítria (Y20a), zircão (ZrSi04), zircônia parcialmente e totalmente estabilizada com ítria (Zr02), pirofilita ( Al2Si4OlO(OHh), .alumina (Al2Oa) e nitreto de boro hexagonal (h-BN). Estes substratos foram produzidos, em sua maioria, a partir da sinterização de pós micrométricos em altas temperaturas. Além do estudo em relação a possíveis candidatos alternativos ao tradicional silício para o crescimento de filmes auto-sustentáveis, procuramos encontrar substratos onde o filme aderisse bem e cujas propriedades tribológicas pudessem ser melhoradas com o recobrimento com filme de diamante.Dentre os materiais selecionados, constatamos que a topografia da superfície relacionada à densidade de contornos de grão, desempenha um papel relevante na nucleação do diamante. Além disso, os materiais que favorecem a formação de carbonetos conduziram a melhores resultados na nucleação e crescimento do filme, indicando que a ação da atmosfera reativa do CVD com o substrato também contribui decisivamente para o processo de nucleação. A partir dos resultados obtidos, concluímos que a aderência do filme de diamante ao zircão é excelente, assim como a qualidade do filme, o que pode serexplorado convenientemente caso as propriedades mecânicas do sinterizado de zircão sejam adequadas. No caso da zircônia parcialmente estabilizada, os resultados obtidos foram surpreendentes e este material poderia substituir o convencional substrato de silício para a deposição de filmes auto-sustentados de diamante, com inúmeras vantagens, dentre elas o fato de ser reutilizável e de não ser necessário ataque com ácidos para remoção do substrato, o que evita a geração de resíduos químicos.

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O objetivo do trabalho foi avaliar a emergência das espécies de plantas daninhas Euphorbia heterophylla e Bidens pilosa em áreas de produção de feijão e de trigo, após o cultivo de plantas de cobertura. O trabalho foi conduzido em área sob sistema de plantio direto na palha, manejado por cinco anos consecutivos, na Fazenda Capivara, da Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Arroz e Feijão, localizada no município de Santo Antônio de Goiás, GO. O solo do local é classificado como Latossolo Vermelho distrófico. Os tratamentos foram constituídos pela combinação de sete plantas de cobertura de solo: braquiarão (Brachiaria brizantha) - cv. Marandu; braquiarão em consórcio com o milho (Zea mays) - híbrido HT BRS 3150; guandu-anão (Cajanus cajan); milheto (Pennisetum glaucum) - cv. BN-2; mombaça (Panicum maximum) cv. Mombaça; sorgo granífero (Sorghum bicolor) - cv. BR 304; e estilosantes (Stylosanthes guianensis) - cv. Mineirão e por duas culturas cultivadas em sucessão nas áreas: feijão cv. Pérola e trigo - Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) 42. Todas as plantas de cobertura foram cortadas no mesmo dia, utilizando-se um triturador de palhada, e deixadas na superfície do solo. As semeaduras do feijão e do trigo foram realizadas sessenta dias após o corte das culturas de cobertura. Foram realizadas duas contagens do número de plantas emergidas de E. heterophylla e de B. pilosa, separadas em três estágios de crescimento (plantas com menos de duas folhas, de duas a quatro folhas e com mais de quatro folhas). Entre as plantas de cobertura testadas, braquiarão e mombaça se mostraram as mais promissoras em reduzir a emergência de plantas daninhas em cultivos subseqüentes, apresentando resultados significativos na diminuição do número de plantas de E. heterophylla estabelecidas nas áreas cultivadas com feijão ou com trigo. Não se constataram diferenças quanto à capacidade das culturas de feijão e de trigo em reduzir a população de E. heterophylla e B. pilosa.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)