526 research outputs found
CoQ10 and Aging.
The aging process includes impairment in mitochondrial function, a reduction in anti-oxidant activity, and an increase in oxidative stress, marked by an increase in reactive oxygen species (ROS) production. Oxidative damage to macromolecules including DNA and electron transport proteins likely increases ROS production resulting in further damage. This oxidative theory of cell aging is supported by the fact that diseases associated with the aging process are marked by increased oxidative stress. Coenzyme Q10 (CoQ10) levels fall with aging in the human but this is not seen in all species or all tissues. It is unknown whether lower CoQ10 levels have a part to play in aging and disease or whether it is an inconsequential cellular response to aging. Despite the current lay public interest in supplementing with CoQ10, there is currently not enough evidence to recommend CoQ10 supplementation as an anti-aging anti-oxidant therapy
Faddeev-Jackiw Analysis of Topological Mass Generating Action
We analyze the gauge symmetry of a topological mass generating action in four
dimensions which contains both a vector and a second rank antisymmetric tensor
fields. In the Abelian case, this system induces an effective mass for the
vector gauge field via a topological coupling in the presence of a
kinetic term for the antisymmetric tensor field , while maintaining a gauge
symmetry. On the other hand, for the non-Abelian case the field does not
have a gauge symmetry unless an auxiliary vector field is introduced to the
system. We analyze this change of symmetry in the Faddeev-Jackiw formalism, and
show how the auxiliary vector field enhances the symmetry. At the same time
this enhanced gauge symmetry becomes reducible. We also show this phenomenon in
this analysis.Comment: 20 pages, REVTe
Calcretes of the Bauru group (cretaceous), Brazil: petrology and geological significance
The calcareous sandstones and sandy limestones of the Bauru Group have been frequently mentioned in geologic literature of Brazil since the beginning of this century, but this Group has only recently been studied in detail and reliably divided into formations about two years ago. Only in 1973 was a detailed investigation carried out especially focusing on the petrologic, chemical and isotopic properties of these sediments, which for the first time were interpreted as calcretes. This paper reinterprets these petrologic studies and their geological significance in the light of recent literature on the calcretes in the world, and the recent revision of Bauru Group stratigraphy.Os arenitos calcíticos e os calcários arenosos do Grupo Bauru têm sido freqüentemente mencionados na literatura geológica brasileira desde o início deste século, mas este grupo foi só recentemente estudado em detalhe e apropriadamente subdividido em formações há cerca de dois anos. Somente em 1973 foi executada uma pesquisa detalhada, enfocando especialmente as propriedades petrológicas, químicas e isotópicas desses sedimentos, quando foram pela primeira vez interpretados como calcretes. Neste trabalho, os estudos petrológicos e seus significados geológicos são reinterpretados a luz da literatura moderna sobre os calcretes no mundo e da recente revisão estratigráfica do Grupo Bauru
Quaternary sedimentary environments in comprida Island, state of São Paulo, Brazil
The coastal plain between the towns of Cananéia and Iguape is very important as it contains the most extensive Quaternary coastal sedimentation in the State of São Paulo, Brazil. Comprida Island, the most prominent physiographic feature in this geological context, is essentially formed of shallow marine sands. Sedimentological analysis made it possible to characterize the texture and mineralogy of 126 samples of sediments from the different sub-environments of Comprida Island. Grain size analysis of the sands, treated by the SAHU method (1964), indicates high-energy and low-viscosity deposition in beach, shallow marine and eolian environments. Morphometric and heavy-mineral studies suggest that Holocene sands are derived from the Cananéia Formation (Pleistocene), the Precambrian Crystalline Complex, and the Upper Precambrian Açungui Group. The combined foraminiferal content of 26 of the samples consists of twenty-six species belonging to twenty-one genera, where Ammonia beccarii (Linné) and Nonionella atlantica (Cushman) are the dominant species. Data on these micro-organisms emphasize the importance of foraminifera in the interpretation of beach zone dynamics and show the necessity of considering the relations of these assemblages to the pattern of circulation of water masses and to such biological controls as the ecological succession of benthonic communities.A planície costeira entre as cidades de Cananéia e Iguape é muito importante porque ela contém a sedimentação quaternária mais extensa do litoral do Estado de São Paulo, Brasil. Ilha Comprida, a mais proeminente feição fisiográfica neste contexto geológico, é essencialmente formada de areias de ambiente marinho raso. Análises sedimentológicas tornaram possível a caracterização da textura e mineralogia de 126 amostras de sedimentos de diferentes subambientes da Ilha Comprida. Os resultados das análises granulométricas de areias, tratados pelo método de SAHU (1964), indicaram deposição em ambiente praial, marinho raso e eólico de alta energia e baixa viscosidade. Estudos morfométricos e de minerais pesados de areias do Holoceno sugerem uma fonte múltipla relacionada à FormaçãQ Cananéia (Pleistoceno), ao Complexo Cristalino do Precambriano e às rochas do Grupo Açungui do Precambriano Superior
Statistical transmutation of quantum bosonic strings coupled to general four-dimensional Chern-Simons theory
A bosonic string coupled to the generalized Chern-Simons theory in 3+1D
acquires a magnetic field along itself, when it is closed, and a topological
charge at its extremity, when it is open. We construct the creation operators
for the full quantum field states associated to these strings and determine the
dual algebra satisfied by them. We show that the creation operator fo the
composite state of a quantum closed bosonic string, bearing a magnetic flux,
and a topologically charged open bosonic string, possesses generalized
statistics. The relation of our results with previous approaches to the problem
is also established.Comment: 4 pages, Revtex
Clinical indicators of occult musculoskeletal pain in aggressive dogs
AGGRESSIVE behaviour by dogs is the most frequent behaviour
problem reported to veterinary behaviour clinics (Bamberger and
Houpt 2006, Fatjo and others 2007). The behaviour is a serious
problem for the victims (Weiss and others 1998) and for the
animals themselves, since it often reflects a negative underlying
emotional state, especially if associated with pain (Bamberger
and Houpt 2006, Hsu and Sun 2010). Pain may lower the dog’s
general threshold for aggressive behaviour, while also encouraging
specific aggressive displays as part of a protective/defensive
response (Rutherford 2002, Muir and others 2004, Landsberg
and others 2013). Beaver (1983) has suggested that more than a
quarter (28.2 per cent) of dogs exhibiting aggression do so
because of a medical condition, including pain, but pain-related
aggression has been considered to account for only a small per
cent of the total caseload in behaviour clinics, that is, 2–3.3 per
cent (Beaver 1983, Borchelt 1983). However, when pain is identi-
fied, the data from Beaver (1983) suggest the prognosis is excellent,
with all cases in her case review reported to have a
successful treatment outcome. A recent small case series of
aggressive dogs with a pain focus indicated that musculoskeletal
pain from hip dysplasia and osteoarthritis of the elbow was the
main cause of pain, occurring in 75 per cent (nine of 12 cases) of
these cases (Camps and others 2012)
Bioecologia e controle de Spodoptera frugiperda em milho.
bitstream/item/67387/1/Documento-344.pd
Symmetry transform in the Faddeev-Jackiw quantization of dual models
We study the presence of symmetry transformations in the Faddeev-Jackiw
approach for constrained systems. Our analysis is based in the case of a
particle submitted to a particular potential which depends on an arbitrary
function. The method is implemented in a natural way and symmetry generators
are identified. These symmetries permit us to obtain the absent elements of the
sympletic matrix which complement the set of Dirac brackets of such a theory.
The study developed here is applied in two different dual models. First, we
discuss the case of a two-dimensional oscillator interacting with an
electromagnetic potential described by a Chern-Simons term and second the
Schwarz-Sen gauge theory, in order to obtain the complete set of non-null Dirac
brackets and the correspondent Maxwell electromagnetic theory limit.Comment: 22 pages, RevTex file, no figur
Comparação de Desempenho Entre a Formulação Direta do Método dos Elementos de Contorno Com Funções Radiais e o Método dos Elementos Finitos em Problemas de Poisson e Helmholtz
Este presente trabalho objetiva avaliar o desempenho do MECID (Método dos Elementos de Interpolação Direta) para resolver o termo integral referente à inércia na equação de Helmholtz e, deste modo, permitir a modelagem do problema de autovalor assim como calcular as frequências naturais, comparando-o com os resultados obtidos pelo Método dos Elementos Finitos, gerado pela formulação clássica de Galerkin. Ainda com o intuito de avaliar o desempenho do MECID, alguns problemas governados pela Equação de Poisson também serão previamente analisados.
Os problemas resolvidos se aplicam em diferentes e importantes áreas da engenharia, como na transmissão de calor, no eletromagnetismo e em problemas elásticos particulares. Em termos numéricos, sabe-se das dificuldades existentes na aproximação precisa de distribuições mais complexas de cargas, fontes ou sorvedouros no interior do domínio para qualquer técnica de contorno. No entanto, este trabalho mostra que, não obstante tais dificuldades, o desempenho do Método dos Elementos de Contorno é superior, tanto no cálculo da variável básica, quanto na sua derivada. Para tanto, são resolvidos problemas bidimensionais referentes a membranas elásticas, esforços em barras devido ao peso próprio e problemas de determinação de frequências naturais em problemas acústicos em domínios fechados, dentre outros apresentados, utilizando malhas com diferentes graus de refinamento, além de elementos lineares para o MECID e funções base de interpolação polinomial de grau (um) para o MEF. São geradas curvas de desempenho através do cálculo do erro médio percentual para cada malha, demonstrando a convergência e a precisão de cada método. Os resultados também são comparados com as soluções analíticas, quando disponíveis, para cada exemplo resolvido.
Palavras chave: Elementos de Contorno, Funções Radiais, Problemas de Campo Escala
Entre a cordilheira e o mar: exploração e evangelização jesuítica no Chile
This article analyzes a series of incursions carried out by Jesuit missionaries in areas that are presently part of the Chilean territory. Several writings that resulted from these incursions provide information on the practices of evangelism and territorial exploration implemented by the Jesuits. Key words: Chile, Jesuits, missions, Indians, texts.Este artigo analisa um conjunto de incursões realizadas por missionários da Companhia de Jesus em áreas que hoje compreendem o território chileno, e das quais resultaram diversos escritos que permitem uma aproximação com as práticas de evangelização e exploração territorial levadas a cabo pelos inacianos. Palavras-chave: Chile, jesuítas, missões, índios, textos
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