660 research outputs found
Numerical simulation study of the dynamical behavior of the Niedermayer algorithm
We calculate the dynamic critical exponent for the Niedermayer algorithm
applied to the two-dimensional Ising and XY models, for various values of the
free parameter . For we regain the Metropolis algorithm and for
we regain the Wolff algorithm. For , we show that the mean
size of the clusters of (possibly) turned spins initially grows with the linear
size of the lattice, , but eventually saturates at a given lattice size
, which depends on . For , the Niedermayer
algorithm is equivalent to the Metropolis one, i.e, they have the same dynamic
exponent. For , the autocorrelation time is always greater than for
(Wolff) and, more important, it also grows faster than a power of .
Therefore, we show that the best choice of cluster algorithm is the Wolff one,
when compared to the Nierdermayer generalization. We also obtain the dynamic
behavior of the Wolff algorithm: although not conclusive, we propose a scaling
law for the dependence of the autocorrelation time on .Comment: Accepted for publication in Journal of Statistical Mechanics: Theory
and Experimen
Magnetic properties and critical behavior of disordered Fe_{1-x}Ru_x alloys: a Monte Carlo approach
We study the critical behavior of a quenched random-exchange Ising model with
competing interactions on a bcc lattice. This model was introduced in the study
of the magnetic behavior of Fe_{1-x}Ru_x alloys for ruthenium concentrations
x=0%, x=4%, x=6%, and x=8%. Our study is carried out within a Monte Carlo
approach, with the aid of a re-weighting multiple histogram technique. By means
of a finite-size scaling analysis of several thermodynamic quantities, taking
into account up to the leading irrelevant scaling field term, we find estimates
of the critical exponents \alpha, \beta, \gamma, and \nu, and of the critical
temperatures of the model. Our results for x=0% are in excellent agreement with
those for the three-dimensional pure Ising model in the literature. We also
show that our critical exponent estimates for the disordered cases are
consistent with those reported for the transition line between paramagnetic and
ferromagnetic phases of both randomly dilute and Ising models. We
compare the behavior of the magnetization as a function of temperature with
that obtained by Paduani and Branco (2008), qualitatively confirming the
mean-field result. However, the comparison of the critical temperatures
obtained in this work with experimental measurements suggest that the model
(initially obtained in a mean-field approach) needs to be modified
Padrões sequenciais de comportamento de frangos de corte em condição termoneutra e de estresse por frio na fase inicial de criação.
RESUMO - Esse trabalho apresenta uma abordagem baseada em padrões sequenciais para estimar o bem-estar de frangos de corte a partir de atributos ambientais e comportamentais. Foram utilizados dados tabulados de experimentos realizados em Câmara de Preferência Ambiental (CPA). Em seguida, o algoritmo GSP (Generalized Sequential Patterns) para mineração de padrões sequenciais foi utilizado para estudar o conforto térmico de frangos de corte. Os resultados revelaram que a mineração de padrões sequencias é uma técnica simples e útil para estimar o bem-estar de frangos de corte, permitindo a identificação de relações temporais entre estresse térmico e o comportamento das aves.CIIC 2018. Nº 17604
Análise de padrões comportamentais de frangos de corte em condições de estresse térmico por calor.
Resumo - Este trabalho apresenta uma abordagem baseada em padrões sequenciais para estimar o bem-estar de frangos de corte a partir de atributos ambientais e comportamentais. Foram utilizados dados tabulados de experimentos realizados em Câmara de Preferência Ambiental (CPA). Em seguida, o algoritmo Generalized Sequential Patterns (GSP) para mineração de padrões sequenciais foi utilizado para estudar o conforto térmico de frangos de corte. Os resultados mostraram que as temperaturas utilizadas para impor o estresse térmico por calor tiveram pouco efeito sobre o comportamento dos frangos de corte.Editores técnicos: Carla Geovana do Nascimento Macário, Carla Cristiane Osawa, Flávia Bussaglia Fiorini, Maria Fernanda Moura, Poliana Fernanda Giachetto
Macronutrientes em solos e pastagens nativas da região Norte do Estado do Piauí.
A pesquisa destinou-se avaliar os niveis de nitrogênio, fósforo e potássio no solo e na parte aérea das pastagens nativas, em municipios representativos da região Norte do Estado do Piauí, em função das épocas do ano (seca e chuvosa).Editores: Ângela Maria Vieira Batista; Severino Benone Paes Barbosa; Mércia Virginia Ferreira dos Santos; Lúcia Maia Cavalcanti Ferreira
Migração celular distinta induzida por Leishmania infantum chagasi e saliva de Lutzomyia longipalpis em um modelo de pool hemorrágico
Recruitment of a specific cell population after Leishmania infection can influence the outcome of the disease. Cellular migration in response to Leishmania or vector saliva has been reported in air pouch model, however, cellular migration induced by Leishmania associated with host's blood and vector saliva in this model has not been described. Herein we investigated cellular migration into air pouch of hamster after stimulation with combination of L. chagasi and host's blood and Lutzomyia longipalpis saliva. Migration induced by saliva was 3-fold more than those induced by L. chagasi alone. Additionally, L. chagasi associated with blood and saliva induced significantly even more leukocytes into air pouch than Leishmania alone. L. chagasi recruited a diverse cell population; however, most of these cells seem to have not migrated to the inflammatory exudate, remaining in the pouch lining tissue. These results indicate that L. chagasi can reduce leukocyte accumulation to the initial site of infection, and when associated with vector saliva in the presence of blood components, increase the influx of more neutrophils than macrophages, suggesting that the parasite has developed a strategy to minimize the initial inflammatory response, allowing an unlimited progression within the host. This work reinforces the importance of studies on the salivary components of sand fly vectors of leishmaniasis in the transmission process and the establishment of the infection.O recrutamento de uma população de células específicas após infecção por Leishmania pode influenciar o resultado da doença. A migração celular em resposta a Leishmania ou saliva do vetor tem sido reportada utilizando o modelo da bolsa de ar subcutânea, entretanto, a migração celular induzida por Leishmania associada com o sangue do hospedeiro e saliva do vetor neste modelo ainda não foi descrita. Neste trabalho foi investigada a migração celular no modelo da bolsa de ar subcutânea em hamster após a estimulação com a combinação de L. chagasi, sangue do hospedeiro e saliva de Lutzomyia longipalpis. A migração induzida por saliva foi três vezes maior do que a induzida por L. chagasi sozinha. Adicionalmente, L. chagasi associada com sangue e saliva induziu significativamente ainda mais leucócitos no exsudato inflamatório do que o estímulo com Leishmania sozinha. L. chagasi recrutou uma população de células distintas, no entanto, a maioria dessas células parece não ter migrado para o exsudato inflamatório, permanecendo no tecido da bolsa de ar. Estes resultados indicam que L. chagasi pode reduzir o acúmulo de leucócitos para o local inicial da infecção e que quando associada à saliva do vetor e na presença de componentes do sangue aumenta o influxo de mais neutrófilos do que macrófagos, sugerindo que o parasito desenvolveu uma estratégia para minimizar a resposta inflamatória inicial, permitindo uma progressão ilimitada dentro do hospedeiro. Este trabalho reforça a importância de mais estudos sobre os componentes da saliva dos vetores das leishmanioses no processo de transmissão e no estabelecimento da infecção
Suscetibilidade da mosca-dos-chifres, Haematobia irritans irritans (Diptera: Muscidae), a inseticidas no Brasil.
Since horn fly populations became established throughout Brazil, complaints regarding control failure have increased around the country. A broad survey to evaluate the susceptibility of horn flies to both organophosphate (OP) and pyrethroid insecticides was conducted from October 2000 to April 2003. Bioassays using filter papers impregnated with cypermethrin, permethrin or diazinon were conducted on 154 horn fly populations in 14 states and 78 municipalities
Aboveground biomass availability in native and cultivated pastures in the Pantanal Nhecolandia, Brazil.
This study aimed to monitor the variation of forage mass availability of Pantanal areas with native and mixed pasture, grazing place for cattle. It is part of PECUS Network - Greenhouse gases (GHG) dynamics in livestock production systems from Brazil.(Embrapa Gado de Corte. Documentos, 216). Coordenador Roberto Giolo de Almeida. II SIGEE. Disponível em: . Acesso em: 01 dez. 2016
Noise-induced gastric lesions: a light and electron microscopy study of the rat gastric wall exposed to low frequency noise
Ionic Liquids Based on Oxidoperoxido-Molybdenum(VI) Complexes with a Chelating Picolinate Ligand for Catalytic Epoxidation
UID/QUI/50006/2019 UID/Multi/04378/2019 UIDB/50011/2020 UIDP/50011/2020 contract foreseen in the numbers 4, 5 and 6 of article 23 of the Decree-Law 57/2016 of 29 August, changed by Law 57/2017 of 19 July.Ionic oxidoperoxido-molybdenum(VI) complexes of the type [Cat][MoO(O2)2(pic)], with pic = N,O-chelated picolinate ligand and Cat = monocation, were prepared in high yields (82–95%) from the precursor complex [H3O][MoO(O2)2(pic)] via [H]+ cation exchange for 1-ethyl-3-methylimidazolium [EMIM]+, 1-butyl-3-methylimidazolium [BMIM]+, 1-octyl-3-methylimidazolium [OMIM]+, N-cetylpyridinium [C16Py]+, and N-methyl-N,N,N-trioctylammonium [Aliquat]+. The structure and purity of the ionic compounds were assessed by 1H and 13C NMR, FT-IR, and elemental analysis (C, H, N), and the electrochemical properties were studied by differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The [Cat][MoO(O2)2(pic)] compounds showed promising catalytic epoxidation activity based on the model reaction of cis-cyclooctene with tert-butyl hydroperoxide as oxidant. The type of cation influenced the physical state of the compound and the catalytic performance.publishersversionpublishe
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