12,758 research outputs found
Analysing and controlling the tax evasion dynamics via majority-vote model
Within the context of agent-based Monte-Carlo simulations, we study the
well-known majority-vote model (MVM) with noise applied to tax evasion on
simple square lattices, Voronoi-Delaunay random lattices, Barabasi-Albert
networks, and Erd\"os-R\'enyi random graphs. In the order to analyse and to
control the fluctuations for tax evasion in the economics model proposed by
Zaklan, MVM is applied in the neighborhod of the noise critical . The
Zaklan model had been studied recently using the equilibrium Ising model. Here
we show that the Zaklan model is robust and can be reproduced also through the
nonequilibrium MVM on various topologies.Comment: 18 pages, 7 figures, LAWNP'09, 200
Estimativas de herdabilidade e correlações genéticas de produções parciais e total de leite de cabras mestiças.
O objetivo desde trabalho foi estimar as herdabilidades, repetibilidades e correlações genéticas para as produções parciais acumuladas e produção total de leite de cabras mestiças. Os dados utilizados foram obtidos de 29.703 controles leiteiros, resultantes de 1055 lactações de 400 cabras F1 Pardo-Alpina x Moxotó no período de 1988 a 1997, pertencente ao CNPC-EMBRAPA. As estimativas dos componentes de covariâncía foram obtidas pelo método da Máxima Verossimilhança Restrita, por meio do modelo animal utilizando o Programa Multiple Trait Derivate-Free Restricted Maximum Likelihood (MTDFREML). Estudou-se o efeito fixo estação-ano de parição e ordem de lactaçâo e como covariável o peso da matriz ao parto (linear) e o peso total das crias (linear). Como efeito aleatório, inclui-se o efeito genético aditivo e o efeito não correlacionado de ambiente permanente. As estimativas obtidas de herdabilidade e repetibilidade para as produções parciais aos 30, 60, 90, 120,150 dias de lactaçâo e para a produção de leite total foram 0,27 + 0,15; 0,31 + 0,15; 0,31+ 0,15; 0,31 + 0,15; 0,30 + 0,15; 0,22 + 0,15 e 0,64; 0,51; 0,58; 0,54; 0,55 e 0,48, respectivamente. As características foram correlacionadas geneticamente variando na mesma direção e sentido. As correlações genéticas obtidas encontraram-se no intervalo de 0,68 a 0,98.Disponível em Separata
On the Temperley-Lieb reflection matrices
This work concerns the boundary integrability of the spin-s
Temperley-Lieb model. A systematic computation method is
used to constructed the solutions of the boundary Yang-Baxter equations. For
half-integer, a general free parameter solution is presented.
It turns that for integer, the general solution has free
parameters. Moreover, some particular solutions are discussed.Comment: LaTex 17 page
Horse spleen segmentation technique as large animal model of preclinical trials
The parenchymal distribution of the splenic artery was studied in order to obtain anatomical basis for partial splenectomy. Thirty two spleens were studied, 26 spleens of healthy horses weighing 320 to 450kg, aged 3 to 12 years and 6 spleens of fetus removed from slaughterhouse. The spleens were submitted to arteriography and scintigraphy in order to have their vascular pattern examined and compared to the external aspect of the organ aiming establish anatomo-surgical segments. All radiographs were photographed with a digital camera and the digital images were submitted to a measuring system for comparative analysis of areas of dorsal and ventral anatomo-surgical segments. Anatomical investigations into the angioarchitecture of the equine spleen showed a paucivascular area, which coincides with a thinner external area, allowing the organ to be divided in two anatomo-surgical segments of approximately 50% of the organ each.A distribuição parenquimal da artéria esplênica foi estudada com o objetivo de obter base anatômica elementos para a realização de esplenectomias parciais. Trinta e dois baços foram estudados, 26 de equinos saudáveis, com peso entre 320 a 450kg e idade de 3 a 12 anos, e seis baços de fetos obtidos em matadouro. Os baços foram submetidos a arteriografias e cintilografias para examinar o padrão vascular e comparar com o aspecto externo do órgão, procurando estabelecer segmentos anatomo-cirurgicos. Todas as ragiografias foram fotografadas com câmera digital e as imagens digitais foram submetidas a um programa de mensuração para análise comparativa das áreas dos dos segmentos anátomo-cirúrgicos dorsal e ventral. Investigações anatômicas sobre a angiorquitetura do baço equino mostrou uma área paucivascular que coincide com a área externa mais fina, permitindo que o órgão seja dividido em dois segmentos anatomo-cirúrgicos com aproximadamente 50% do órgão em cada
Desempenho de cultivares de girassol (Helianthus annuus. L.) no Estado do Rio Grande do Norte.
Este trabalho teve como objetivo avaliar o comportamento produtivo de diversas cultivares de girassol. O ensaio foi instalado no Município de Canguaretama/RN no ano agrícola de 2007( 6º22 ? S, 35º 07? W, altitude de 5m, temperatura média anual de 25 ºC O solo é classificado como latossolo amarelo de textura arenosa. A precipitação ocorrida durante a condução do ensaio foi de 904,6 mm. O delineamento experimental foi blocos ao acaso, com quatro repetições. Fez-se uma adubação utilizando-se a fórmula: 60-80-60 kg/ha mais 2 kg/ha de boro.Os materiais avaliados mostraram-se precoces, com uma média de 39 dias para atingir o florescimento inicial. Os rendimentos médios de grãos das cultivares ficaram entre 1.356 kg/ha e 2.581 kg/ha, com média geral de 1.829 kg/ha.Três cultivares apresentaram rendimentos médios de grãos acima de 2.200 kg/ha, sobressaindo-se os materiais M 734, HLA 863 e GIRA 19 e com o teor de óleo superior a 42 %
Chemical Potential and the Nature of the Dark Energy: The case of phantom
The influence of a possible non zero chemical potential on the nature
of dark energy is investigated by assuming that the dark energy is a
relativistic perfect simple fluid obeying the equation of state (EoS),
(). The entropy condition, ,
implies that the possible values of are heavily dependent on the
magnitude, as well as on the sign of the chemical potential. For , the
-parameter must be greater than -1 (vacuum is forbidden) while for not only the vacuum but even a phantomlike behavior () is
allowed. In any case, the ratio between the chemical potential and temperature
remains constant, that is, . Assuming that the dark energy
constituents have either a bosonic or fermionic nature, the general form of the
spectrum is also proposed. For bosons is always negative and the extended
Wien's law allows only a dark component with which includes
vacuum and the phantomlike cases. The same happens in the fermionic branch for
are permmited only if . The thermodynamics and statistical arguments constrain the
EoS parameter to be , a result surprisingly close to the maximal
value required to accelerate a FRW type universe dominated by matter and dark
energy ().Comment: 7 pages, 5 figure
New reflection matrices for the U_q(gl(m|n)) case
We examine super symmetric representations of the B-type Hecke algebra. We
exploit such representations to obtain new non-diagonal solutions of the
reflection equation associated to the super algebra U_q(gl(m|n)). The boundary
super algebra is briefly discussed and it is shown to be central to the super
symmetric realization of the B-type Hecke algebraComment: 13 pages, Latex. A few alterations regarding the representations. A
reference adde
Human cachexia induces changes in mitochondria, autophagy and apoptosis in the skeletal muscle
Cachexia is a wasting syndrome characterized by the continuous loss of skeletal muscle mass due to imbalance between protein synthesis and degradation, which is related with poor prognosis and compromised quality of life. Dysfunctional mitochondria are associated with lower muscle strength and muscle atrophy in cancer patients, yet poorly described in human cachexia. We herein investigated mitochondrial morphology, autophagy and apoptosis in the skeletal muscle of patients with gastrointestinal cancer-associated cachexia (CC), as compared with a weight-stable cancer group (WSC). CC showed prominent weight loss and increased circulating levels of serum C-reactive protein, lower body mass index and decreased circulating hemoglobin, when compared to WSC. Electron microscopy analysis revealed an increase in intermyofibrillar mitochondrial area in CC, as compared to WSC. Relative gene expression of Fission 1, a protein related to mitochondrial fission, was increased in CC, as compared to WSC. LC3 II, autophagy-related (ATG) 5 and 7 essential proteins for autophagosome formation, presented higher content in the cachectic group. Protein levels of phosphorylated p53 (Ser46), activated caspase 8 (Asp384) and 9 (Asp315) were also increased in the skeletal muscle of CC. Overall, our results demonstrate that human cancer-associated cachexia leads to exacerbated muscle-stress response that may culminate in muscle loss, which is in part due to disruption of mitochondrial morphology, dysfunctional autophagy and increased apoptosis. To the best of our knowledge, this is the first report showing quantitative morphological alterations in skeletal muscle mitochondria in cachectic patients
Postmenopausal Osteoporosis reference genes for qPCR expression assays
Osteoporosis (OP) is a multifactorial disease influenced by genetic factors in more than half of the cases. In spite of the efforts to clarify the relationship among genetic factors and susceptibility to develop OP, many genetic associations need to be further functionally validated. Besides, some limitations as the choice of stably expressed reference genes (RG) should be overcome to ensure the quality and reproducibility of gene expression assays. To our knowledge, a validation study for RG in OP is still missing. We compared the expression levels, using polymerase chain reaction quantitative real time (qPCR) of 10 RG (G6PD, B2M, GUSB, HSP90, EF1A, RPLP0, GAPDH, ACTB, 18 S and HPRT1) to assess their suitability in OP analysis by using GeNorm, Normfinder, BestKeeper and RefFinder programs. A minimal number of two RG was recommended by GeNorm to obtain a reliable normalization. RPLP0 and B2M were identified as the most stable genes in OP studies while ACTB, 18 S and HPRT1 were inadequate for normalization in our data set. Moreover, we showed the dramatic effects of suboptimal RG choice on the quantification of a target gene, highlighting the importance in the identification of the most appropriate reference gene to specific diseases. We suggest the use of RPLP0 and B2M as the most stable reference genes while we do not recommend the use of the least stable reference genes HPRT1, 18 S and ACTB in OP expression assays using PBMC as biological source. Additionally, we emphasize the importance of individualized and careful choice in software and reference genes selection
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