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Caio Augusto Perazza  Jos Bento Sterman Ferraz  Vera Maria Fonseca Almeida‐Val  Alexandre Wagner Silva Hilsdorf 《Aquaculture Research》2019,50(10):i-i

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Woodland and floral richness boost bumble bee density in cranberry resource pulse landscapes     

Pfeiffer  Vera  Silbernagel  Janet  Guédot  Christelle  Zalapa  Juan 《Landscape Ecology》2019,34(5):979-996

Landscape Ecology - Native pollinators provide an important ecosystem service for many pollination-dependent fruit crops, but require nesting and foraging resources in proximity to target crop...  相似文献   

Interactions of Protein and Starch Studied Through Amyloglucosidase Action     

Nicoletta Guerrieri  Lucia Eynard  Vera Lavelli  Paolo Cerletti 《Cereal Chemistry》1997,74(6):846-850

The access of amyloglucosidase to the carbohydrate molecule was taken as a measure of interactions occurring among starch, amylose, amylopectin, β-dextrin and purified gluten, gliadins, high molecular weight glutenin subunits, or bovine serum albumin when they were mixed together and gelatinized before digestion. The most relevant decrease in liberated glucose, denoting coverage of some reaction sites for amyloglucosidase, occurred when gliadins were mixed with the carbohydrates. Other proteins were not as effective as gliadins. Amylopectin was not affected by any protein. Comparison of results allows some hypothesis to be formulated about the influence of structure on molecular interactions.  相似文献   

Carabids (Coleoptera: Carabidae) in a forest patchwork: a connectivity analysis of the Bereg Plain landscape graph     

Ferenc Jordán  Tibor Magura  Béla Tóthmérész  Vera Vasas  Viktor Ködöböcz 《Landscape Ecology》2007,22(10):1527-1539

For many species, one important key to persistence is maintaining connectivity among local populations that allow for dispersal and gene flow. This is probably true for carabid species (Coleoptera:Carabidae) living in the fragmented forests of the Bereg Plain (NE Hungary and W Ukraine). Based on field data, we have drafted a landscape graph of the area representing the habitat network of these species. Graph nodes and links represented two kinds of landscape elements: habitat (forest) patches and corridors, respectively. The quality of habitat patches and corridors were ranked (from low (1) to high (4)), reflecting local population sizes in the case of patches and estimated permeability in the case of corridors. We analysed (1) the positional importance of landscape elements in maintaining the connectivity of the intact network, (2) the effect of inserting hypothetical corridors into the network, (3) the effects of improving the quality of the existing corridors, and (4) how to connect every patch in a cost-effective way. Our results set quantitative priorities for conservation practice by identifying important corridors: what to protect, what to build and what to improve. Several network analytical techniques were used to account for the directed (source-sink) and highly fragmented nature of the landscape graph. We provide conservation priority ranks for the landscape elements and discuss the conditions for the use of particular network indices. Our study could be of extreme relevance, since a new highway is being planned through the area.  相似文献   

Sex ratio,cornual implantation and ovarian activity in the pregnant water buffalo—Bubalus bubalis1     

William G. Von Vale  Jose S. Sousa  Haroldo F. L. Ribeiro  Otvio M. Ohashi 《Reproduction in domestic animals》1981,16(5):214-217

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Haemolytic Assay of Sheep Serum Complement1     

Otakar Barta  Vera Barta  Ruth A. Shirley  Janet D. McMurry 《Zoonoses and public health》1975,22(3):254-262

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Genetic association between milk yield,stayability, and mastitis in Holstein cows under tropical conditions     

Natalia Irano  Annaiza Braga Bignardi  Lenira El Faro  Mário Luiz Santana Jr  Vera Lúcia Cardoso  Lucia Galvão Albuquerque 《Tropical animal health and production》2014,46(3):529-535

The objective of this study was to estimate genetic parameters for milk yield, stayability, and the occurrence of clinical mastitis in Holstein cows, as well as studying the genetic relationship between them, in order to provide subsidies for the genetic evaluation of these traits. Records from 5,090 Holstein cows with calving varying from 1991 to 2010, were used in the analysis. Two standard multivariate analyses were carried out, one containing the trait of accumulated 305-day milk yields in the first lactation (MY1), stayability (STAY) until the third lactation, and clinical mastitis (CM), as well as the other traits, considering accumulated 305-day milk yields (Y305), STAY, and CM, including the first three lactations as repeated measures for Y305 and CM. The covariance components were obtained by a Bayesian approach. The heritability estimates obtained by multivariate analysis with MY1 were 0.19, 0.28, and 0.13 for MY1, STAY, and CM, respectively, whereas using the multivariate analysis with the Y305, the estimates were 0.19, 0.31, and 0.14, respectively. The genetic correlations between MY1 and STAY, MY1 and CM, and STAY and CM, respectively, were 0.38, 0.12, and ?0.49. The genetic correlations between Y305 and STAY, Y305 and CM, and STAY and CM, respectively, were 0.66, ?0.25, and ?0.52.  相似文献   

Crystal structure of the dynein motor domain     

Carter AP  Cho C  Jin L  Vale RD 《Science (New York, N.Y.)》2011,331(6021):1159-1165

Dyneins are microtubule-based motor proteins that power ciliary beating, transport intracellular cargos, and help to construct the mitotic spindle. Evolved from ring-shaped hexameric AAA-family adenosine triphosphatases (ATPases), dynein's large size and complexity have posed challenges for understanding its structure and mechanism. Here, we present a 6 angstrom crystal structure of a functional dimer of two ~300-kilodalton motor domains of yeast cytoplasmic dynein. The structure reveals an unusual asymmetric arrangement of ATPase domains in the ring-shaped motor domain, the manner in which the mechanical element interacts with the ATPase ring, and an unexpected interaction between two coiled coils that create a base for the microtubule binding domain. The arrangement of these elements provides clues as to how adenosine triphosphate-driven conformational changes might be transmitted across the motor domain.  相似文献   

Synthetic polypeptide antagonists of the hypothalamic luteinizing hormone releasing factor   总被引：1，自引：0，他引：1  

W Vale  G Grant  J Rivier  M Monahan  M Amoss  R Blackwell  R Burgus  R Guillemin 《Science (New York, N.Y.)》1972,176(37):933-934

Two analogs of the hypothalamic luteinizing hormone releasing factor modified at the histidine-2 position were tested for biological activity (secretion of luteinizing hormone) in cultures of dispersed rat anterior pituitary cells. The analog in which glycine was substituted for histidine at position 2, [Gly(2)]LRF, behaves as a partial agonist releasing less than 50 percent of the luteinizing hormone secreted at maximum concentrations of the releasing factor, while the analog in which histidine at position 2 is deleted has no significant agonist activity at any of the doses tested. When added to the cultured cells at molar ratios 10(3) to 10(4) times that of the luteinizing hormone releasing factor, both analogs decrease the amount of luteinizing hormone secreted in response to the releasing factor.  相似文献   

Singing icebergs     

Müller C  Schlindwein V  Eckstaller A  Miller H 《Science (New York, N.Y.)》2005,310(5752):1299

Sustained harmonic tremor signals were recorded by the seismographs of the German Neumayer Base seismological network in western Dronning Maud Land, Antarctica. These tremor episodes, lasting up to 16 hours, were recorded up to 820 kilometers from the source. Their spectra show narrow peaks with fundamental frequencies ranging from 0.5 to 6 hertz, more than 30 integer harmonic overtones, and frequency gliding, resembling volcanic tremor. Frequency-wave number analysis suggested a moving source, which was recognized as iceberg B-09A traveling along the coast of eastern Antarctica. The most probable tremor sources are fluid-flow-induced vibrations inside the iceberg's tunnel/crevasse systems.  相似文献