946 resultados para Etnisk segregation
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Engenharia Mecânica - FEG
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Pós-graduação em Engenharia Civil - FEIS
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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A theoretical approach aiming at the prediction of segregation of dopant atoms on nanocrystalline systems is discussed here. It considers the free energy minimization argument in order to provide the most likely dopant distribution as a function of the total doping level. For this, it requires as input (i) a fixed polyhedral geometry with defined facets, and (ii) a set of functions that describe the surface energy as a function of dopant content for different crystallographic planes. Two Sb-doped SnO2 nanocrystalline systems with different morphology and dopant content were selected as a case study, and the calculation of the dopant distributions expected for them is presented in detail. The obtained results were compared to previously reported characterization of this system by a combination of HRTEM and surface energy calculations, and both methods are shown to be equivalent. Considering its application pre-requisites, the present theoretical approach can provide a first estimation of doping atom distribution for a wide range of nanocrystalline systems. We expect that its use will support the reduction of experimental effort for the characterization of doped nanocrystals, and also provide a solution to the characterization of systems where even state-of-art analytical techniques are limited.
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Background: Centromeres are essential for chromosome segregation, yet their DNA sequences evolve rapidly. In most animals and plants that have been studied, centromeres contain megabase-scale arrays of tandem repeats. Despite their importance, very little is known about the degree to which centromere tandem repeats share common properties between different species across different phyla. We used bioinformatic methods to identify high-copy tandem repeats from 282 species using publicly available genomic sequence and our own data.Results: Our methods are compatible with all current sequencing technologies. Long Pacific Biosciences sequence reads allowed us to find tandem repeat monomers up to 1,419 bp. We assumed that the most abundant tandem repeat is the centromere DNA, which was true for most species whose centromeres have been previously characterized, suggesting this is a general property of genomes. High-copy centromere tandem repeats were found in almost all animal and plant genomes, but repeat monomers were highly variable in sequence composition and length. Furthermore, phylogenetic analysis of sequence homology showed little evidence of sequence conservation beyond approximately 50 million years of divergence. We find that despite an overall lack of sequence conservation, centromere tandem repeats from diverse species showed similar modes of evolution.Conclusions: While centromere position in most eukaryotes is epigenetically determined, our results indicate that tandem repeats are highly prevalent at centromeres of both animal and plant genomes. This suggests a functional role for such repeats, perhaps in promoting concerted evolution of centromere DNA across chromosomes.
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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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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Oocyte maturation is a complex process involving nuclear and cytoplasmic maturation. The nuclear maturation is a chromosomal segregation and the cytoplasmic maturation involves the reorganization of the cytoplasmic organelles, mRNA transcription and storage of proteins to be used during fertilization and early embryo development. The mechanism of oocyte maturation in vivo and in vitro still are not totally understood. However it is generally accepted that the second messenger cyclic adenosine monophosphate (cAMP) plays a critical role in the maintenance of meiotic blockage of mammalian oocytes. A relative increase in the level of cAMP within the oocyte is essential for maintaining meiosis block, while a decrease in cAMP oocyte concentration allows the resumption of meiosis. The oocyte cAMP concentration is regulated by a balance of two types of enzymes: adenylate cyclase (AC) and phosphodiesterases (PDEs), which are responsible for the synthesis and degradation of cAMP, respectively. After being synthesized by AC in cumulus cells, cAMP are transferred to the oocyte through gap junctions. Thus, specific subtypes PDEs are able to inhibit or attenuate the spontaneous meiotic maturation of oocytes with PDE4 primarily involved in the metabolism of cAMP in granulosa cells and PDE3 in the oocyte. Although the immature oocytes can resume meiosis in vitro, after being removed from antral follicles, cytoplasmic maturation seems to occur asynchronously with nuclear maturation. Therefore, knowledge of the oocyte maturation process is fundamental for the development of methodologies to increase the success of in vitro embryo production and to develop treatments for various forms of infertility. This review will present current knowledge about the maintenance of the oocyte in prophase arrest, and the resumption of meiosis during oocyte maturation, focusing mainly on the changes that take place in the oocyte.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The feline leukemia virus (FeLV) was described in 1964 by William Jarrett and collaborators wen find viral particles attached to the membrane of lymphoblasts in cat with lymphoma. The virus belongs to the family Retroviridae, subfamily oncornavirus. With worldwide distribution, the occurrence of FeLV has 1.6% in healthy cats and 10.8% in sick cats in Brazil. The mortality of persistently viremic animals in catteries is about 50% in two years and 80% in three years. In catteries that have endemic feline Coronavirus (FCoV), FeLV and / or Feline Immunodeficiency Virus (FIV), the FeLV infection has greater contribution to mortality. The test for infection and FeLV positive cats segregation is the main way to prevent the spread of infection. The diagnostic methods are based on clinical signs and changes compatible with FeLV infection observed by physical examination, complete blood count, X-ray, bone marrow aspirate and biochemical. The viral p27 protein is produced in infected cells in high amounts and is found in abundance in the cytoplasm and in body fluids enabling diagnosed methods such as enzyme-linked immunosorbent assay - ELISA and direct immunofluorescence, detection of viral genome (Chain Reaction Polymerase - PCR) and detection of the virus by virus isolation. Although diagnostic tests are highly sensitive, it should be made more than a confirmatory test, especially serological due to variable characteristic of the progress of infection
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The Health Care Wastes (HCW) present serious risks to health and to the environment, if incorrectly managed, because in addition to the presence of pathogenic agents, the may pollute the soil and the water. Thus, a study was performed aiming at diagnosing the HCW management in Araraquara (SP), identifying the difficulties of the agents (municipal gestors and managers of institutions which generate this wastes) in implanting the HCW management Plan (HCWMP) proposed by ANVISA, in order to subside the HCWMP implantation. The methodology was based on question applications in health centers selected to be the samples, and on quantitative data related to the phases of Treatment and Final Disposal, provided by DAAE. As a result, it was observed that a great part of the interviewed centers managed these wastes according to norm RDC no 306/ 2004 of ANVISA. However, only 24% of the interviewed centers knew about this norm, and only 22% of them had the HCWMP. The difficulties in managing the HCW concentrated in the correct segregation of theses wastes in the generation source. The large number of people involved in this phase suggests the causes of the difficulties.
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In this study we discuss a range of topics related to urban development from the perspective of connection points between the existence of the individual subjects’ lives. In this connection we identified the signs that express an articulation among subjectivity processes and conditions for interference in the real world, relying on circumscribed remarks about spatial configurations and its uses. This way, the substance of our research is structured upon the concept of fashion brands operating new dynamics of urban lifestyles, a strengthened reliance on the physical body’s appearance and the profusion of a supposed “I”, presented as a spectacle. Taking these assertions as new “trends” on building view-points and contemporary cities, we discuss the implications of these currents on how people gather and organize themselves in the urban landscape, making an effort to comprehend how these vogues reverberate on the (re)production of increasingly segregated cities
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The research aims to propose grants for development of Municipal Plan for the Management of Organic Solid Waste generated in the municipality of Rio Claro. The research universe was composed of organic waste generators establishments (markets and grocers). From the registry of commercial establishments provided by the municipal government were identified who presented this typology, which totaled 38 establishments. In this universe the interview was conducted in 15 establishments obtained by directed sampling based on the characteristics of size, type and location. The data collected were the amount generated, disposal of waste, waste separation, collection frequency, reasons for the disposal of waste, frequency of purchase of products. From the data obtained in the field, we estimated the total generation of organic waste in this segment for the municipality. Then, the estimated costs for implementation and operation of a composting center, a way to subsidize the implementation of the management plan was carried out. We opted for the aerobic composting process by the simplicity of operation and because it is a technique already known. The average waste generation was established by tracks (size) with: stores up to 4 boxes (classified as small) generate on average 1511 kg / month, 40% of organic waste, the 5-9 boxes (small/midsize) generate on average 4338 kg / month, 35% organic and the 10 to 19 boxes (midsize) generate on average 7647 kg / month with 32% organic. In total establishments generate 105 t/ month of waste, with 35t / month of organics. 94% of establishments are in font segregation of waste into recyclable, organic and waste, indicating that the proposed management of organic waste is amenable to application without many changes in existing routine in stores. Recyclables are sent for recycling through selective collection held by the cooperative, while the organics are destined for the landfill and feed. The results indicate...