975 resultados para Sullivan, Timothy Daniel, 1862-1913.
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To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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The present study seeks to present a historico-epistemological analysis of the development of the mathematical concept of negative number. In order to do so, we analyzed the different forms and conditions of the construction of mathematical knowledge in different mathematical communities and, thus, identified the characteristics in the establishment of this concept. By understanding the historically constructed barriers, especially, the ones having ontologicas significant, that made the concept of negative number incompatible with that of natural number, thereby hindering the development of the concept of negative, we were able to sketch the reasons for the rejection of negative numbers by the English author Peter Barlow (1776 -1862) in his An Elementary Investigation of the Theory of Numbers, published in 1811. We also show the continuity of his difficulties with the treatment of negative numbers in the middle of the nineteenth century
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The Large Hadron Collider presents an unprecedented opportunity to probe the realm of new physics in the TeV region and shed light on some of the core unresolved issues of particle physics. These include the nature of electroweak symmetry breaking, the origin of mass, the possible constituent of cold dark matter, new sources of CP violation needed to explain the baryon excess in the universe, the possible existence of extra gauge groups and extra matter, and importantly the path Nature chooses to resolve the hierarchy problem - is it supersymmetry or extra dimensions. Many models of new physics beyond the standard model contain a hidden sector which can be probed at the LHC. Additionally, the LHC will be a. top factory and accurate measurements of the properties of the top and its rare decays will provide a window to new physics. Further, the LHC could shed light on the origin of neutralino masses if the new physics associated with their generation lies in the TeV region. Finally, the LHC is also a laboratory to test the hypothesis of TeV scale strings and D brane models. An overview of these possibilities is presented in the spirit that it will serve as a companion to the Technical Design Reports (TDRs) by the particle detector groups ATLAS and CMS to facilitate the test of the new theoretical ideas at the LHC. Which of these ideas stands the test of the LHC data will govern the course of particle physics in the subsequent decades.
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The imprints of domestication and breed development on the genomes of livestock likely differ from those of companion animals. A deep draft sequence assembly of shotgun reads from a single Hereford female and comparative sequences sampled from six additional breeds were used to develop probes to interrogate 37,470 single-nucleotide polymorphisms (SNPs) in 497 cattle from 19 geographically and biologically diverse breeds. These data show that cattle have undergone a rapid recent decrease in effective population size from a very large ancestral population, possibly due to bottlenecks associated with domestication, selection, and breed formation. Domestication and artificial selection appear to have left detectable signatures of selection within the cattle genome, yet the current levels of diversity within breeds are at least as great as exists within humans.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coral snakes in the genus Micrurus are widely distributed in the Neotropics, with more than 50 species already described in this region. They are primarily ground or leaf litter dwellers, feed on snakes or other elongate vertebrates, and tend to reproduce during the rainy season. We present data on the biology of Micrurus pyrrhocryptus from two semideciduous forests of Mato Grosso do Sul state, western Brazil. Two snake species were consumed: the dipsadid Sibynomorphus lavillai and the typhlopid Typhlops brongersmianus. Sexual dimorphism is marked in M. pyrrhocryptus. with males attaining larger sizes and having longer tails. Activity was concentrated in the wet season, when reproduction occurs. The defensive behavior in this species is similar to that displayed by other Micron's, although less pronounced.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Herein I present a new geographical record of Ischnocnema verrucosa Reinhardt and Luetken, 1862 fro northeastern Brazil and briefly discuss the new record with a previous record of similar characteristics.
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The population structure of the penaeidean shrimp Xyphopenacus kroyeri was studied in Ubatuba Bay, Ubatuba, Sd̃ao Paulo, Brazil. The period and site of juvenile recruitment were monitored using a monthly sampling design with eight fixed areas (transects) from September 1995 to August 1996. The population structure was assessed using size frequency distributions (based on carapace length) for each month and sampling area. Females were significantly larger than males, suggesting a differential growth between sexes. The very low occurrence of large adults in the Bay can be related to offshore migration for reproduction. Recruitment occurred throughout the year, with a peak during the summer, when the highest recruitment rates were obtained along inshore transects. The present investigation revealed valuable information on the biology of the species mainly in the study region, which is considered a nursery ground for juveniles of X. kroyeri. The species showed an important variation from the typical life cycle that it is assumed to hold over its entire range and X. kroyeri should be classified as having a life cycle different from that proposed previously in the literature, i.e. the juveniles prefer inshore areas instead of estuaries. Some suggestions for the seabob fishery management are proposed as an alternative for minimising the impact during the harvest period and adjusting the protection schedule.
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The objective of this work was to evaluate the influence of fresh water shrimp Macrobrachium amazonicum (Heller, 1862) in performance of Nile tilapia (Oreochromis niloticus) cultivated in polyculture system and feeding with ration pelleted and mashed. The work was realized in Centro de Pesquisa em Aqüicultura Ambiental-CPAA/IAP - Toledo/PR during 37 days. Were utilized like experimental unit 16 ponds excavated, covered with concrete but with bottom of soil with dimension the 4 x 3 m and useful volume the 3,5 m 3. Were utilized 30 tilapias e 150 shrimps for experimental unit distributed at an entirely randomized design with 4 treatments and 4 replications, where TF: tilapia feeding with ration mashed; TCF: tilapia and shrimp feeding with ration mashed; TP: tilapia feeding with ration pelleted; TCP: tilapia and shrimp feeding with ration pelleted. The density used were the 2,6 fishes/m 2 with medium initial weight the 5,58 ± 0,10 g and initial length the 5,56 cm, and the density of shrimp was the 13 shrimps/m 2 with initial length the 1,04 cm. The temperature was gauged daily, while the variables dissolved oxygen, pH and electrical conductivity, weekly. The quantity of ration supplied was the 10% of total biomass of fishes, with feed frequency the 4 times a day, being corrected weekly in function of the biometry. During the experimental period the medium values of temperature, dissolved oxygen, pH and electrical conductivity of the ponds water were 23,42 ± 0,83°C, 5,32 ± 0,52 mg/L, 7,02 ± 0,39, e 100,96 ± 1,81 μS/ cm respectively. Won't registering any influence of shrimp during the cultivation and the ration pelleted provide the better conversion alimentary and performance of tilapias.