993 resultados para Congar, Yves Marie-Joseph, O.P., 1904-1995
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"A catalogue of some of the principal works illustrated entirely or partly by Joseph Wolf": p. [291]-328.
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Mode of access: Internet.
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Mode of access: Internet.
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On verso of t.-p.: Extracted from the Henry memorial volume published by order of Congress.
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This work is part of the program, "recruitment determinism in scallops" initiated in 1992 by the "Contrat de Baie". The aim of this research was to explain interannual abundance fluctuations observed for Pecten maximus, in the Bay of Brest. To this end an analytical approach to the life cycle of the species was undertaken to determine its critical phases. A phase may be considered as "critical" if the mortality rate at its level varies from one year to the other. Using data from 1989 to 1994, a precise time-table of the "physiological year" of the scallop in the Bay of Brest was determined. Fecundity and gamete production kinetics were estimated from the annual variation in the weight indices of the gonad. In the laboratory, egg quality was estimated following stimulated spawning of newly caught individuals. The digestive activity was estimated by amylase activity measurements during a three year period. Spawning lasts 6 months in the Bay of Brest from March to October. Spawning, muscle and digestive gland growths, are intimately linked to phytoplancton blooms. Gonad production shows a maximum in April-May, and two relative minima in Match and November. These results, which provide detailed understanding of the adult's annual cycle in the Bay of Brest, will be used to interpret the relationship between the annual cycle and larval and post larval abundance and survival. Already, these results are being used to improve spat production in hatcheries.
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Although stable isotope ratios are increasingly used to investigate the trophic ecology of marine organisms, their spatial variations are still poorly understood in the coastal environment. In this study, we measured the stable isotope composition (δ13C, δ15N) of suspended particulate organic matter (SPOM) (primary producer), a suspension feeder, the great scallop Pecten maximus (primary consumer), megabenthic decapods and benthic fishes (secondary consumers) along a depth gradient (from 5m to 155m depth) across the continental shelf of the Bay of Biscay. Although the three trophic levels exhibited similar δ13C patterns along the gradient, the δ15N patterns varied between SPOM, scallops and carnivores. The δ15N difference between SPOM and scallops decreased with increasing depth, suggesting that non trophic factors may affect the stable isotope composition of scallops at deepest sampling stations. An opposed trend was found between scallops and carnivores, suggesting that the trophic level of these carnivores increased at higher depth, possibly as an adaptation to lower prey abundances. Although our results suggest that primary consumers are suitable to establish isotopic baselines in coastal environments, we stress the need for further studies aiming at characterizing the variability of stable isotopes in coastal biota, and the respective effects of baseline, trophic and metabolic factors in their isotopic composition.
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This text describes an experiment on fractional precipitation of a polymer together with determination of average degree of polymerization by NMR. Commercial sodium polyphosphate was fractionated by precipitation from aqueous solution by adding increasing amounts of acetone. The polydisperse salt and nine fractions obtained from it were analyzed by 31P Nuclear Magnetic Resonance and the degree of polymerization of the salts and of the fractions were calculated. Long-chain sodium polyphosphate was also synthesized and analyzed. This experiment was tested in a PChem lab course but it can be used also to illustrate topics of inorganic polymers and analytical chemistry.
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Foram conduzidos dois experimentos com o objetivo de avaliar a utilização de duas fontes de metionina (em pó ou líquida) em rações formuladas com base em aminoácidos digestíveis ou totais para frangas de reposição leves e semipesadas, nas fases inicial (de 1 a 6 semanas de idade) e de crescimento (de 11 a 16 semanas de idade). Em cada experimento, foram utilizadas 384 aves distribuídas em delineamento inteiramente ao acaso, em esquema fatorial 2 × 2 × 2, composto de duas linhagens (Hy-Line W36 e Hy-Line Brown), duas fontes de metionina (HMTBA - 88% e DL-Metionina - 99%) e dois critérios de formulação da dieta (aminoácidos totais e digestíveis), totalizando oito tratamentos, cada um com seis repetições de oito aves. Foram avaliados os consumos de ração, proteína bruta e energia metabolizável, o peso e ganho de peso corporal e a conversão alimentar das aves. Não houve interação entre os fatores para nenhuma das variáveis estudadas. As aves da linhagem Brown apresentaram maior consumo de ração, peso corporal e ganho de peso. As fontes de metionina e os critérios de formulação de ração não influenciaram as características de desempenho. As aves das linhagens W36 e Brown da linhagem Hy-Line apresentam diferentes perfis de desenvolvimento corporal. A metionina em pó (DL-metionina - 99%) ou a líquida (HMTBA - 88%), assim como os critérios de formulação de ração (aminoácidos totais ou digestíveis) proporcionam desempenho semelhante em aves de reposição.
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The principal aim of studies of enzyme-mediated reactions has been to provide comparative and quantitative information on enzyme-catalyzed reactions under distinct conditions. The classic Michaelis-Menten model (Biochem Zeit 49:333, 1913) for enzyme kinetic has been widely used to determine important parameters involved in enzyme catalysis, particularly the Michaelis-Menten constant (K (M) ) and the maximum velocity of reaction (V (max) ). Subsequently, a detailed treatment of the mechanisms of enzyme catalysis was undertaken by Briggs-Haldane (Biochem J 19:338, 1925). These authors proposed the steady-state treatment, since its applicability was constrained to this condition. The present work describes an extending solution of the Michaelis-Menten model without the need for such a steady-state restriction. We provide the first analysis of all of the individual reaction constants calculated analytically. Using this approach, it is possible to accurately predict the results under new experimental conditions and to characterize and optimize industrial processes in the fields of chemical and food engineering, pharmaceuticals and biotechnology.
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This work shows a comparison between the analog performance of standard and strained Si n-type triple-gate FinFETs with high-K dielectrics and TiN gate material. Different channel lengths and fin widths are studied. It is demonstrated that both standard and strained FinFETs with short channel length and narrow fins have similar analog properties, whereas the increase of the channel length degrades the early voltage of the strained devices, consequently decreasing the device intrinsic voltage gain with respect to standard ones. Narrow strained FinFETs with long channel show a degradation of the Early voltage if compared to standard ones suggesting that strained devices are more subjected to the channel length modulation effect. (C) 2008 Elsevier Ltd. All rights reserved.
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The brain-derived neurotrophic factor (BDNF) Val66Met polymorphism has been proposed as a possible candidate for involvement in the pathophysiology of bipolar disorder ( BD). To determine whether an association exists between the BDNF Val66Met genotype and morphometric abnormalities of the brain regions involved in memory and learning in BD and healthy subjects. Forty-two BD patients and 42 healthy subjects were studied. Interactions between BDNF Val66Met genotype and diagnosis in gray ( GM) volumes were analyzed using an optimized voxel-based morphometry technique. Declarative memory function was assessed with the California Verbal Learning Test II. Left and right anterior cingulate GM volumes showed a significant interaction between genotype and diagnosis such that anterior cingulate GM volumes were significantly smaller in the Val/Met BD patients compared with the Val/Val BD patients (left P = 0.01, right P = 0.01). Within-group comparisons revealed that the Val/Met carriers showed smaller GM volumes of the dorsolateral prefrontal cortex compared with the Val/Val subjects within the BD patient (P = 0.01) and healthy groups (left P = 0.03, right P = 0.03). The Val/Met healthy subjects had smaller GM volumes of the left hippocampus compared with the Val/Val healthy subjects (P<0.01). There was a significant main effect of diagnosis on memory function (P = 0.04), but no interaction between diagnosis and genotype was found (P = 0.48). The findings support an association between the BDNF Val66Met genotype and differential gray matter content in brain structures, and suggest that the variation in this gene may play a more prominent role in brain structure differences in subjects affected with BD. Neuropsychopharmacology (2009) 34, 1904-1913; doi: 10.1038/npp.2009.23; published online 18 March 2009
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Bleeding is not uncommon following endoscopic sphincterotomy. Supra-papillary puncture (SPP) might be safer than standard cannulation (SC) techniques in patients with coagulopathy. The aim of the study was to compare the safety and effectiveness of SPP and SC. This was a prospective case control intervention study. Decompensated cirrhotic patients with coagulopathy and choledocolithiasis underwent SC and SPP methods for biliary access. One hundred five patients (56 [53.3%] men, mean [SD] age 56 [15.8]) underwent ERCP. SC and SPP were performed in 63 and 42 patients, respectively. Biliary access was achieved in 56/63 (89%) and 40/42 (95%) of patients undergoing SC and SPP, respectively (P = 0.13; 95% CI [-0.16; 0.03]). Complications occurred in 10/63 (15.8%) patients undergoing SC and 5/42 (11.9%) SPP (P = 0.28; 95% CI [-0.17, 0.16]). Five (7.9%) and two (3.2%) episodes of post-sphincterotomy bleeding was seen in the SC and SPP groups, respectively (P = 0.36; 95% CI [-0.16, 0.05]). In contrast, three (4.8%) episodes of pancreatitis were seen in the SC and none in the SPP group (P = 0.05; 95% CI [0.001; 0.004]). A cost-effectiveness analysis demonstrated that SPP is an acceptable alternative at an ICER of US$ 5,974.92 per additional successful procedure. SPP is a safe and effective technique for the management of common bile duct stones in decompensated cirrhotic patients. Conditional to the willingness-to-pay and to the local ERCP-related costs, SPP is also a cost-effective alternative to the SC methods. SPP is associated with a lower rate of complications but larger studies to validate these findings are necessary.
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Proteins secreted to the extracellular environment or to the periphery of the cell envelope, the secretome, play essential roles in foraging, antagonistic and mutualistic interactions. We hypothesize that arms races, genetic conflicts and varying selective pressures should lead to the rapid change of sequences and gene repertoires of the secretome. The analysis of 42 bacterial pan-genomes shows that secreted, and especially extracellular proteins, are predominantly encoded in the accessory genome, i.e. among genes not ubiquitous within the clade. Genes encoding outer membrane proteins might engage more frequently in intra-chromosomal gene conversion because they are more often in multi-genic families. The gene sequences encoding the secretome evolve faster than the rest of the genome and in particular at non-synonymous positions. Cell wall proteins in Firmicutes evolve particularly fast when compared with outer membrane proteins of Proteobacteria. Virulence factors are over-represented in the secretome, notably in outer membrane proteins, but cell localization explains more of the variance in substitution rates and gene repertoires than sequence homology to known virulence factors. Accordingly, the repertoires and sequences of the genes encoding the secretome change fast in the clades of obligatory and facultative pathogens and also in the clades of mutualists and free-living bacteria. Our study shows that cell localization shapes genome evolution. In agreement with our hypothesis, the repertoires and the sequences of genes encoding secreted proteins evolve fast. The particularly rapid change of extracellular proteins suggests that these public goods are key players in bacterial adaptation.