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Composition and orientation effects on the final recrystallization texture of coarse-grained Nb-containing AISI 430 ferritic stainless steels

SIQUEIRA, R. P.; SANDIM, H. R. Z.; OLIVEIRA, T. R.; RAABE, D.
Fonte: ELSEVIER SCIENCE SA Publicador: ELSEVIER SCIENCE SA
Tipo: Artigo de Revista Científica
ENG
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Composition and orientation effects on the final recrystallization texture of three coarse-grained Nb-containing AISI 430 ferritic stainless steels (FSSs) were investigated. Hot-bands of steels containing distinct amounts of niobium, carbon and nitrogen were annealed at 1250 degrees C for 2h to promote grain growth. In particular, the amounts of Nb in solid solution vary from one grade to another. For purposes of comparison, the texture evolution of a hot-band sheet annealed at 1030 degrees C for 1 min (finer grain structure) was also investigated. Subsequently, the four sheets were cold rolled up to 80% reduction and then annealed at 800 degrees C for 15 min. Texture was determined using X-ray diffraction and electron backscatter diffraction (EBSD). Noticeable differences regarding the final recrystallization texture and microstructure were observed in the four investigated grades. Results suggest that distinct nucleation mechanisms take place within these large grains leading to the development of different final recrystallization textures. (c) 2011 Elsevier B.V. All rights reserved.; FAPESP; CNPq (Brazil)[05/60131-5]

Edge effects as the principal cause of area effects on birds in fragmented secondary forest

BANKS-LEITE, Cristina; EWERS, Robert M.; METZGER, Jean-Paul
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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Bird communities in tropical forests are strongly affected by both patch area and habitat edges. The fact that both effects are intrinsically confounded in space raises questions about how these two widely reported ecological patterns interact, and whether they are independent or simply different spatial manifestations of the same phenomenon. Moreover, do small patches of secondary forest, in landscapes where the most sensitive species have gone locally extinct, exhibit similar patterns to those previously observed in fragmented and continuous primary forests? We addressed these questions by testing edge-related differences in vegetation structure and bird community composition at 31 sites in fragmented and continuous landscapes in the imperilled Atlantic forest of Brazil. Over a two-year period, birds were captured with mist nets to a standardized effort of 680 net-hours at each site (similar to 22 000 net-hours resulting in 3381 captures from 114 species). We found that the bird community in patches of secondary forest was degraded in species composition compared to primary continuous forest, but still exhibited a strong response to edge effects. In fragmented secondary forests, edge and area effects also interacted, such that the magnitude of edge to interior differences on bird community composition declined markedly with patch size. The change in bird species composition between forest interiors and edges was similar to the change in community composition between large and small patches (because species had congruent responses to edge and area)...

Effect of somatic cell count and mastitis pathogens on milk composition in Gyr cows

Malek dos Reis, Carolina Barbosa ; Barreiro, Juliana Regina; Mestieri, Lucineia; Porcionato, Marco Aurélio de Felício ; Santos, Marcos Veiga dos
Fonte: London Publicador: London
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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Abstract Background Gyr cows are well adapted to tropical conditions, resistant to some tropical diseases and have satisfactory milk production. However, Gyr dairy herds have a high prevalence of subclinical mastitis, which negatively affects their milk yield and composition. The objectives of this study were (i) to evaluate the effects of seasonality, mammary quarter location (rear x front), mastitis-causing pathogen species, and somatic cell count (SCC) on milk composition in Gyr cows with mammary quarters as the experimental units and (ii) to evaluate the effects of seasonality and somatic cell count (SCC) on milk composition in Gyr cows with cows as the experimental units. A total of 221 lactating Gyr cows from three commercial dairy farms were selected for this study. Individual foremilk quarter samples and composite milk samples were collected once a month over one year from all lactating cows for analysis of SCC, milk composition, and bacteriological culture. Results Subclinical mastitis reduced lactose, nonfat solids and total solids content...

Variantes genéticas de kappa-caseína em vacas leiteiras e características físico-químicas e de composição do leite ; Kappa-casein polimorphism in dairy cows and, physico-chemical properties and composition of milk

Lima, Ygor Vinicius Real de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 16/12/2005 PT
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361.745%
Os objetivos gerais do presente estudo foram avaliar o efeito do polimorfismo genético da kappa-caseína, da raça e da estação do ano sobre as características físico-químicas (acidez, pH e crioscopia), composição (gordura, lactose, sólidos totais, contagem de células somáticas, uréia, proteína bruta, proteína verdadeira, nitrogênio não protéico e nitrogênio não caseinoso) e estabilidade do leite. Foram selecionados 11 rebanhos leiteiros comerciais, sendo cinco deles da raça Holandesa e seis da raça Girolanda, dos quais foram amostradas em média 122 vacas em lactação por rebanho, totalizando 1350 vacas amostradas em três períodos: 2 no período seco e 1 no período chuvoso. As vacas selecionadas foram analisadas quanto a composição e propriedades físico-químicas do leite, assim como para a determinação do polimorfismo de kappa-caseína. O presente trabalho foi dividido em dois estudos, no primeiro avaliou-se os efeitos da raça e estação do ano sobre características físico-químicas, composição e estabilidade do leite. Foi observado efeito de raça sobre acidez titulável, pH, lactose, uréia e estabilidade do leite. O efeito de sazonalidade mostrou-se significativo sobre pH, crioscopia, teores de lactose...

Efeito da composição do material particulado fino, PM2,5 e residual oil fly ash (ROFA), como determinante do potencial mutagênico e tóxico celular: um estudo em bioensaios vegetais e animais; The role of fine particulate matter composition of PM2,5 and ROFA in the cell mutagenic potential and toxicity: a vegetable and animal bioassay study

Oliveira, Regiani Carvalho de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 02/10/2006 PT
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360.6942%
O consenso sobre os efeitos prejudiciais da material particulado atmosférico (MP) para a saúde humana é apoiado por um grande número de trabalhos epidemiológicos e experimentais mas a capacidade para definir qual o componente mais importante envolvido em sua toxicidade é dificultado pela sua grande complexidade de composição. O objetivo deste estudo é avaliar os efeitos de diferentes partículas de poluição atmosférica, quanto à origem e quanto a sua composição, sobre o sistema biológico através de 3 experimentos. O efeito do PM2,5 urbano de São Paulo, Brasil, coletado durante greve de ônibus foi avaliada através do TRAD-MN para a mutagenicidade e o teste de inibição de mitose em células meristemáticas da raiz de Allium cepa. para a toxicidade. Utilizamos o palato de rã para avaliar os parâmetros funcionais (transporte mucociliar -TMC, freqüência do batimento ciliar - FBC e diferença de potencial - DP) e morfométricos (espessura do epitélio, produção de muco) do aparelho mucociliar exposto ao ROFA, proveniente de usina siderúrgica e ao PM2,5 urbano. A análise comparativa da composição do PM2,5 através da ativação com nêutrons, fluorescência de raio-X e cromatografia gasosa espectrometria de massa mostrou redução na concentração de elementos traços de metais...

Efeito da suplementação de L-carnitina combinada ao exercício aeróbio sobre a composição corporal, lipidemia, gasto energético e desempenho físico de adultos do sexo masculino e feminino; The effect of combined L-carnitine supplementation to aerobic exercise on body composition, lipid, energy expenditure and adult physical performance of male and female

Coelho, Christianne de Faria
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 30/11/2004 PT
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358.53875%
O uso de suplementos alimentares à base de carnitina tem se tornado bastante popular dentre atletas. Nos seus possíveis efeitos biológicos, constam o emagrecimento e o melhor condicionamento aeróbio frente ao exercício físico. Embora o uso difundido também entre não-atletas, há poucas evidências científicas nestes grupos populacionais, particularmente adultos. O objetivo deste estudo foi avaliar os efeitos da suplementação de L-carnitina associada ao exercício físico aeróbio sobre a composição corporal e lipídica sanguínea, gasto energético de repouso e desempenho aeróbio de adultos clinicamente saudáveis. Foram selecionados 21 indivíduos voluntários de 40 a 58 anos de idade, de ambos os sexos (9 homens e 12 mulheres), com índice de Massa Corporal (IMC) entre 25 e 35 kg/m2, participantes de protocolo de exercícios físicos aeróbios supervisionados (80min/sessão, 3-5x/semana, 70 a 80% da freqüência cardíaca máxima para idade) há pelo menos 12 semanas. Após avaliação inicial (M0), foram divididos aleatoriamente em grupos: suplementado (G1; N=11), recebeu 1,8g/dia de L-carnitina e placebo (G2; N=10), recebeu maltodextrina, ambos mantidos nesta intervenção dietética por 30 dias consecutivos. Concluído o período dietético (M1)...

Effects of HCl on the ultrasound catalyzed TEOS hydrolysis as determined by a calorimetric study

Donatti, D. A.; Vollet, D. R.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 99-104
ENG
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The acid catalyzed and ultrasound stimulated hydrolysis of solventless tetraethoxysilane-water mixtures was studied at 39°C as a function of HCl added to the mixtures (log[HCl]-1 ranged from 0.8 to 2.0), The reaction was carried out in a specially designed device, in which a steady state heat flow is maintained, while sonication is taking place, if no reaction is expected to occur. The exothermal hydrolysis reaction causes an increasing temperature (ΔTt) as a function of the reaction time, t. The isothermal hydrolysis rate constant, k, has been evaluated from the experimental ΔTt versus t data, after corrections for the increasing temperature effects, by using a method resulting from our theoretical modeling based on a dissolution and reaction mechanism. The hydrolysis rate constant fits closely a k α [H+] law as expected for this kind of hydrogen-ion catalyzed reaction.

Avaliação dos efeitos do ácido linoléico conjugado (CLA), dos fitosteróis e de sua combinação na regulação de parâmetros bioquímicos, oxidativos e na composição corporal de ratos Sprague Dawley; Evaluation of the effects of conjugated linoleic acid (CLA), phytosterols and their combination in the regulation of biochemical and oxidative parameters and body composition in Sprague Dawley rats

Rafaela da Silva Marineli
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 02/03/2012 PT
Relevância na Pesquisa
361.745%
Têm-se atribuído inúmeros efeitos biológicos ao ácido linoléico conjugado (CLA) e aos fitosteróis. O CLA vem sendo estudado principalmente por sua ação anticarcinogênica, imunomoduladora, reguladora do balanço energético, pela alteração do perfil lipídico e da composição corporal, influência sobre o processo de resistência à insulina e aumento da oxidação lipídica. Os fitosteróis levam a redução dos níveis de colesterol sérico e, consequentemente, a prevenção de doenças cardiovasculares, além de outros efeitos benéficos reportados recentemente, como atividade antidiabetogênica e antioxidante. É possível que a interação entre CLA e fitosteróis melhore ou potencialize os seus efeitos biológicos isolados. O objetivo deste trabalho foi avaliar os efeitos causados pela associação da suplementação de CLA e de fitosteróis no perfil lipídico, hormonal e oxidativo, na sensibilidade à insulina e na composição corporal in vivo. Foi realizado um ensaio biológico com 40 ratos machos Sprague Dawley, saudáveis, em crescimento divididos em 5 grupos (n=8) e alimentados por 9 semanas com dieta normolipídica (AIN-93G) suplementada com 2% dos compostos lipídicos de interesse: grupo S com óleo de soja (padrão)...

Microstructure and surface composition effects on the transpassivation of NiTi wires for implant purposes

Oliveira,Anderson Garbuglio de; Giacomelli,Fernando Carlos; Giacomelli,Cristiano; Spinelli,Almir
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2005 EN
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The microstructure and surface composition effects on the transpassivation behavior of untreated and heat treated at 500 ºC NiTi wires used for implant purposes were investigated by electrochemical techniques (open circuit potential and potentiodynamic polarization curves), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The potential at which the passive film breaks down (Eb) (transpassivation) was found to be strictly dependent on both the chemical composition of oxide covering layer and the microstructure of the biomaterial. It could be concluded that the disordered microstructure of untreated NiTi is highly resistant to transpassivation (Eb ~ 1.00 V/SCE), but the presence of a native oxygen rich oxide film onto it makes the dissolution easier (Eb ~ 0.00 V/SCE). Upon thermally treating, the microstructure becomes ordered and less resistant to dissolution (Eb ~ 0.12 V/SCE), but in this case the presence of an oxygen rich native film influenced Eb in a lower extent (Eb ~ 0.03 V/SCE).

Investigating Lipid Composition Effects on the Mechanosensitive Channel of Large Conductance (MscL) Using Molecular Dynamics Simulations

Elmore, Donald E.; Dougherty, Dennis A.
Fonte: Biophysical Society Publicador: Biophysical Society
Tipo: Artigo de Revista Científica
Publicado em /09/2003 EN
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Previous experimental work has shown that the functional properties of the mechanosensitive channel of large conductance (MscL) are affected by variations in lipid composition. Here, we utilize molecular dynamics simulations of Mycobacterium tuberculosis MscL to investigate such lipid composition effects on a molecular level. In particular, two sets of simulations were performed. In the first, trajectories using lipids with different headgroups (phosphatidylcholine and phosphatidylethanolamine) were compared. Protein-lipid interactions were clearly altered by the headgroup changes, leading to conformational differences in the C-terminal region of M. tuberculosis MscL. In the second set of simulations, lipid tails were gradually shortened, thinning the membrane over a molecular dynamics trajectory. These simulations showed evidence of hydrophobic matching between MscL and the lipid membrane, as previously proposed. For all simulations, protein-lipid interaction energies in the second transmembrane region were correlated to mutagenic data, emphasizing the importance of lipid interactions for proper MscL function.

Racial/Ethnic Composition and Violence: Size-of-Place Variations in Percent Black and Percent Latino Effects on Violence Rates1

Feldmeyer, Ben; Steffensmeier, Darrell; Ulmer, Jeffery T.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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According to racial invariance positions and mainstream sociological perspectives on race and crime, race differences in structural conditions should account for most if not all of the racial composition (or percent black) effect on aggregate-level violence rates. However, prior research (mostly conducted prior to 1990) generally provides mixed or contrary evidence for this position, showing instead that greater concentrations of blacks are linked to increased violence even after accounting for racial differences in socioeconomic conditions. The current study uses recent data and a novel unit of analysis to go beyond extant research in two ways. First, we include percent Latino in our examination of the extent to which both racial and ethnic composition effects on violent crime rates are mediated by racial/ethnic disparities in socioeconomic disadvantage. Second, we test whether racial/ethnic composition effects are conditioned by size of place, through the use census places as a uniquely varying unit of analysis. We find that both black and Latino composition effects are partly explained by controlling for structural conditions (especially structural disadvantage), but this characterizes smaller places much more than the largest, most urbanized places.

The Effects of International Trade on Water Use

Kagohashi, Kazuki; Tsurumi, Tetsuya; Managi, Shunsuke
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 13/07/2015 EN
Relevância na Pesquisa
358.53875%
The growing scarcity of water resources worldwide is conditioned not only by precipitation changes but also by changes to water use patterns; the latter is driven by social contexts such as capital intensity, trade openness, and income. This study explores the determinants of water use by focusing on the effect of trade openness on the degree to which water is withdrawn and consumed. Previous studies have conducted analyses on the determinants of water use but have ignored the endogeneity of trade openness. To deal with this endogeneity problem, we adopt instrumental variable estimation and clarify the determinants of water use. The determinants of water use are divided into scale, technique, and composition effects. Calculating each trade-induced effect, we examine how trade openness affects the degree of water use. Our results show that while trade has a positive effect on water withdrawal/consumption through trade-induced scale effects and direct composition effects, the trade-induced technique and the indirect composition effect, both of which exhibit a negative sign, counteract the scale effect and the direct composition effect, resulting in reduced water withdrawal/consumption. The overall effect induced by trade is calculated as being in the range of –1.00 to –1.52; this means that the overall effect of a 1% increase in the intensity of trade openness reduces the degree of water withdrawal/consumption by roughly 1.0–1.5%...

Análise da Composição das Culturas no Espaço Goiano, de 1990 a 2009, baseada em índices de Shift-Share; Análise da Composição das Culturas no Espaço Goiano, de 1990 a 2009, baseada em índices de Shift-Share; Analysis of the Composition of Cultures in Space Goiano, 1990 to 2009, based on Shift-Share indices; Analysis of the Composition of Cultures in Space Goiano, 1990 to 2009, based on Shift-Share indices

MENDES, Heloísio Caetano
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Agronegócio; Ciências Agrárias Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Agronegócio; Ciências Agrárias
Tipo: Dissertação Formato: application/pdf
POR
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The analyses of the dynamics of the crops composition in the State of Goiás was first started by Yokoyama (1988). Here, is made a continuity of this work and methodology enlargement elements like maps and graphics to better scrutinize the phenomenon throw the use of shift-share rates. Further socio economic inferences are based in agricultural frontier´s theory. The mathematical methods and uses, of the shift-share rates, are discussed. Using this model, the area effects are decomposed into scale and substitution effects, and it shows the geographic location effects for the selected microrregiões, and for this also the production effects. The agricultural frontier model is presented in basics ideas. The indices are presented for individual and the set of crops in the microrregiões and so are fluctuation of production of the set and location of crops in the State of Goiás. The results point changes in the crops composition in the State of Goiás. Staple food production in the new context, despite changes of territory of crops, it maintains important role in National context. It presents results about the important discussion that involves sugar-cane expansion, relations to soy-beans and cattle and conclusions about crop relations to ´cerrados´ area. The crop period goes is from 1990 to 2009.; A análise da composição das culturas no Estado de Goiás foi um trabalho iniciado por Yokoyama (1988). Neste realiza-se uma continuação aliada a uma atualização metodológica ao utilizar elementos como mapas e gráficos que permitiram uma visão mais ampla dos fenômenos evidenciados pelos índices Shift-Share. Neste trabalho também ocorre uma renovação da análise...

Accounting for changes in the Spanish wage distribution : the role of employment composition effects

Carrasco, Raquel; Jimeno, Juan F.; Orteaga, Carolina
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: Trabalho em Andamento Formato: application/pdf
Publicado em //2011 ENG
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Despite a rapid decrease in unemployment and strong GDP and employment growth, real wages barely increased in Spain over the period 1995-2006. An explanation of this lack of growth may rely on employment composition effects derived from structural changes, such as the rise in the weights of employment in the construction and services sectors, the increase in female employment participation, and the arrival of large immigration inflows. Using data from three waves of the Structure of Earnings Survey, we break down observed wage changes into those due to varying worker and job characteristics and variations of the returns to those characteristics. Quantile regressions are used to estimate wage equations at different percentiles and to construct the counterfactual wage distributions that would have been observed had individual and job characteristics remain constant over time. Our main finding is that the lack of growth of Spanish real wages over the period 1995-2006 is mainly due to the decrease of returns to characteristics, specially education and labour market experience, which is more noticeable at the upper deciles of the wage distribution, and not to changes in employment composition, which when taken over a wide set of worker and job characteristics...

Efeitos de diferentes frequencias semanais de treinamento com pesos sobre a composição corporal e capacidades motoras em homens idosos; Effects of differential weekly frequencies of weight training on body composition and motor capacities in older men

Claudinei Ferreira dos Santos
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 09/03/2009 PT
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Os efeitos do treinamento com pesos realizados com diferentes intensidades, freqüências e volumes trazem respostas benéficas e são bem difundidos para populações de jovens e atletas. No entanto, estudos que procuram avaliar os efeitos do treinamento com pesos realizados em diferentes freqüências semanais são escassos para populações idosas. Assim, o propósito da presente pesquisa foi analisar e comparar os efeitos do treinamento com pesos sobre indicadores da sarcopenia, composição corporal, hipertrofia muscular e das capacidades físicas força muscular e flexibilidade de homens idosos submetidos a duas ou três sessões semanais de treinamento com pesos. Para tanto fizeram parte da amostra 27 indivíduos, subdivididos em: grupo treinamento com freqüência semanal de 2 sessões de treino (GT2, n=9), grupo treinamento com freqüência semanal de 3 sessões de treino (GT3, n=10), ambos submetidos a um programa de treinamento com pesos por um período de 16 semanas, e um grupo controle (GC, n=8) que não se envolveu com nenhuma rotina de exercícios físicos durante o período do experimento. Os indicadores da sarcopenia e composição corporal foram determinados por Absortometria Radiológica de Dupla Energia (DEXA). A sarcopenia foi determinada pelo índice relativo de músculo esquelético. Como indicador de hipertrofia muscular...

Sequence composition effects on the stabilities of triple helix formation by oligonucleotides containing N7-deoxyguanosine.

Brunar, H; Dervan, P B
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/06/1996 EN
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A nonnatural nucleoside, 7-(2-deoxy-beta-D-erythro-pento-furanosyl)-guanine (d7G), mimics protonated cytosine and specifically binds GC base pairs within a pyrimidine - purine - pyrimidine triple helix. The differences in association constants (KT) determined by quantitative footprint titration experiments at neutral pH reveal dramatic sequence composition effects on the energetics of triple helix formation by oligonucleotides containing d7G. Purine tracts of sequence composition 5'-d(AAAAAGAGAGAGAGA)-3' are bound by oligonucleotide 5'-d(TTTTT7GT7GT7GT7GT7GT)-3' three orders of magnitude less strongly than by 5'-d(TTTTTmCTmCTmCTmCTmCT)-3' (KT = 1.5 x 10(6) M(-1) and KT > or = 3 x 10(9) M(-1) respectively). Conversely, purine tracts of sequence composition 5'-d(AAAAGAAAAGGGGGGA)-3' are bound by oligonucleotide 5'-d(TTTTmCTTTT7G7G7G7G7G7GT)-3' five orders of magnitude more strongly than by 5'-d(TTTTmCTTTTmCmCmCmCmCT)-3' (KT > or = 3 x 10(9) M(-1) and KT < 5 x 10(4) M(-1) respectively). The complementary nature of d7G and mC expands the repertoire of G-rich sequences which may be targeted by triple helix formation.

Counterion and composition effects on discotic nematic lyotropic liquid crystals - I. Size and order

Ahumada, H.; Weiss López, Boris Enrique; Araya Maturana, Ramiro Juan; Olea, Andrés F.; Montecinos, R.
Fonte: ACADEMIC PRESS INC ELSEVIER SCIENCE Publicador: ACADEMIC PRESS INC ELSEVIER SCIENCE
Tipo: Artículo de revista
EN
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Counterion and composition effects on the size and interface dynamics of discotic nematic lyotropic liquid crystals made of tetradecyltrimethylammonium halide (TTAX)-decanol (DeOH)-water-NaX, with X = Cl- and Br-, were investigated using NMR and fluorescence spectroscopies. The dynamics of the interface was examined by measuring deuterium quadrupole splittings from HDO (0.1% D2O in H2O) and 1,1-dideuterodecanol (20% 1,1-dideuterodecanol in DeOH) in 27 samples of each liquid crystal. Aggregation numbers, N-D, from 15 samples of each mesophase were obtained using the fluorescence of pyrene quenched by hexadecylpyridinium chloride. N-D of TTAB and TTAC are about 230 30 and 300 20, respectively. ND of TTAC increases with increasing concentration of all mesophase components, whereas TTAB shows no correlation between size and composition. The dimension of these aggregates prevents the occurrence of undulations, previously observed in lamellar phases. The quadrupole splitting of decanol-d(2) in TTAC is about 5 kHz smaller than in TTAB, and the splitting of HDO is observed only in TTAB. All results are consistent with a more dynamic TTAC interface. The TTAC aggregate should be more dissociated from counterions and the excess ammonium-ammonium electrostatic repulsions contribute to increase the mobility of the interface components.

School composition effects in Spain

Di Paolo, Antonio
Fonte: Xarxa de Referència en Economia Aplicada (XREAP) Publicador: Xarxa de Referència en Economia Aplicada (XREAP)
Tipo: Trabalho em Andamento Formato: application/pdf
Publicado em //2010 ENG
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Drawing on PISA data of 2006, this study examines the impact of socio-economic school composition on science test score achievement for Spanish students in compulsory secondary schools. We define school composition in terms of the average parental human capital of students in the same school. These contextual peer effects are estimated using a semi-parametric methodology, which enables the spillovers to affect all the parameters of the educational production function. We also deal with the potential problem of self-selection of student into schools, using an artificial sorting that we argue to be independent from unobserved student’s abilities. The results indicate that the association between socio-economic school composition and test score results is clearly positive and significantly higher when computed with the semi-parametric approach. However, we find that the endogenous sorting of students into schools plays a fundamental role, given that the spillovers are significantly reduced when this selection process is ruled out from our measure of school composition effects. Specifically, the estimations suggest that the contextual peer effects are moderately positive only in those schools where the socio-economic composition is considerably elevated. In addition...

Sequence composition effects on the stabilities of triple helix formation by oligonucleotides containing N7-deoxyguanosine

Brunar, Helmut; Dervan, Peter B.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em 01/06/1996
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A nonnatural nucleoside, 7-(2-deoxy-β-D-erythro-pento-furanosyl)- guanine (d7G), mimics protonated cytosine and specifically binds GC base pairs within a pyrimidine - purine - pyrimidine triple helix. The differences in association constants (KT) determined by quantitative footprint titration experiments at neutral pH reveal dramatic sequence composition effects on the energetics of triple helix formation by oligonucleotides containing d7G. Purine tracts of sequence composition 5'-d(AAAAAGAGAGAGAGA)-3' are bound by oligonucleotide 5'- d(TTTTT7GT7GT7GT7GT7GT)-3' three orders of magnitude less strongly than by 5'-d(TTTTTmCTmCTmCTmCTmCT)-3' (KT = 1.5 x 10(6) M(-1) and KT > or = 3 x 10(9) M(-1) respectively). Conversely, purine tracts of sequence composition 5'-d(AAAAGAAAAGGGGGGA)-3' are bound by oligonucleotide 5'- d(TTTTmCTTTT7G7G7G7G7G7GT)-3' five orders of magnitude more strongly than by 5'-d(TTTTmCTTTTmCmCmCmCmCT)-3' (KT > or = 3 x 10(9) M(-1) and KT < 5 x 10(4) M(-1) respectively). The complementary nature of d7G and mC expands the repertoire of G-rich sequences which may be targeted by triple helix formation.

Integrative effects of vine water relations and grape ripeness level of Vitis vinifera L. cv. Shiraz/Richter 99. II. grape composition and wine quality

Hunter,J.J.; Volschenk,C.G.; Novello,V; Pisciotta,A.; Booyse,M.; Fouché,G.W.
Fonte: South African Journal of Enology and Viticulture Publicador: South African Journal of Enology and Viticulture
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 EN
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Regulation of grapevine water status is a common practice to manipulate grape composition and wine quality. In this investigation the effect of plant water status (two field water capacity-based irrigation levels, 75% and 100%, applied at single and combined vine developmental stages) and ripeness level (harvesting at different soluble solid levels) on grape composition and wine quality of Vitis vinifera L. cv. Shiraz/ Richter 99 was determined. Integrative effects of vine water relations and grape ripeness level, specifically in a Mediterranean high winter rainfall area, have not yet been investigated systematically. Source:sink mechanisms and dynamics and compositional and physical changes during both green berry and ripening periods (and in response to environment changes), seemed critical for the final grape composition and wine quality/style. Despite relatively favourable conditions of the experiment terroir, additional water was still required to obtain best grape and wine quality. Skin colour and total phenolic contents were stimulated in particular by 75% (field water capacity) pea size (PS) irrigation, post-véraison (PV) irrigation and 75% pea size+post-véraison irrigation, until the last harvest stage. Treatments that included post-véraison irrigation were not negative in terms of ripening parameters. Increasing total soluble solids with ripening were not followed in parallel by anthocyanin potential. Anthocyanin extractability increased with ripening. A late...