965 resultados para Baryon Asymmetry


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Evidence exists that both right and left hemisphere attentional mechanisms are mobilized when attention is directed to the right visual hemifield and only right hemisphere attentional mechanisms are mobilized when attention is directed to the left visual hemifield. This arrangement might lead to a rightward bias of automatic attention. The hypothesis was investigated by testing male volunteers, wherein a ""location discrimination"" reaction time task (Experiments 1 and 3) and a ""location and shape discrimination"" reaction time task (Experiments 2 and 4) were used. Unilateral (Experiments 1 and 2) and unilateral or bilateral (Experiments 3 and 4) peripheral visual prime stimuli were used to control attention. Reaction time to a small visual target stimulus in the same location or in the horizontally opposite location was evaluated. Stimulus onset asynchronies (SOAs) were 34, 50, 67, 83 and 100 ms. An important prime stimulus attentional effect was observed as early as 50 ms in the four experiments. In Experiments 2, 3 and 4, this effect was larger when the prime stimulus occurred in the right hemifield than when it occurred in the left hemifield for SOA 100 ms. In Experiment 4, when the prime stimulus occurred simultaneously in both hemifields, reaction time was faster for the right hemifield and for SOA 100 ms. These results indicate that automatic attention tends to favor the right side of space, particularly when identification of the target stimulus shape is required. (c) 2007 Elsevier Inc. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

There is evidence that automatic visual attention favors the right side. This study investigated whether this lateral asymmetry interacts with the right hemisphere dominance for visual location processing and left hemisphere dominance for visual shape processing. Volunteers were tested in a location discrimination task and a shape discrimination task. The target stimuli (S2) could occur in the left or right hemifield. They were preceded by an ipsilateral, contralateral or bilateral prime stimulus (S1). The attentional effect produced by the right S1 was larger than that produced by the left S1. This lateral asymmetry was similar between the two tasks suggesting that the hemispheric asymmetries of visual mechanisms do not contribute to it. The finding that it was basically due to a longer reaction time to the left S2 than to the right S2 for the contralateral S1 condition suggests that the inhibitory component of attention is laterally asymmetric.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We have investigated the magnetic-field asymmetry of the conductance in the nonlinear regime in a small Aharonov-Bohm ring. We have found that the odd-in B and linear in V (the DC bias) correlation function of the differential conductance exhibits periodical oscillations with the Aharonov-Bohm flux. We have deduced the electron interaction constant and analyzed the phase rigidity of the Aharonov-Bohm oscillations in the nonlinear regime. Copyright (C) EPLA, 2009

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A rationalization of the known difference between the (3,4)J(C4H1) and (3,4)J(C1H4) couplings transmitted mainly through the 7-bridge in norbornanone is presented in terms of the effects of hyperconjugative interactions involving the carbonyl group. Theoretical and experimental studies Of (3,4)J(CH) couplings were carried out in 3-endo- and 3-exo-X-2-norbornanone derivatives (X = Cl, Br) and in exo- and endo-2-noborneol compounds. Hyperconjugative interactions were studied with the natural bond orbital (NBO) method. Hyperconjugative interactions involving the carbonyl pi*c(2) =o and sigma*c(2) =o antibonding orbitals produce a decrease of three-bond contribution to both (3,4) J(C4H1) and (3,4)J(C1H4) couplings. However, the latter antibonding orbital also undergoes a strong sigma c(3)-c(4) ->sigma*c(2) =o interaction, which defines an additional coupling pathway for (3,4)J(C4H1) but not for (3,4)J(C1H4). This pathway is similar to that known for homoallylic couplings, the only difference being the nature of the intermediate antibonding orbital; i.e. for (3,4)J(C4H1) it is of sigma*-type, while in homoallylic couplings it is of pi*-type. Copyright (c) 2007 John Wiley & Sons, Ltd.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The possibility of using solar energy during winter depends on the available solar radiation and on the geometry of the receiving surface. For high latitudes, the annual distribution of the available radiation is characterized by high asymmetry with a large amount of solar radiation from high altitude angles during the summer and a small amount of direct radiation from small altitude angles during the winter. This article deals with the origin of the difference between available solar radiation during summer and winter at high latitudes. Factors like the tilt of the earth’s axis, the eccentricity of the earth’s orbit, absorption and scattering of radiation in the atmosphere and seasonal changes in the weather conditions are discussed. Numerical examples of how these factors contribute to the reduction of the winter radiation compared to the summer radiation on surfaces with different orientation in Stockholm, latitude 59.4°N, are given. It is shown that the influence of the atmosphere and seasonal changes in the climate, and not pure earth-sun geometry, are the main reasons why it is hard to utilize solar energy at high latitudes during the winter.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A literatura teórica sobre economia bancária aponta que o relacionamento duradouro entre um emprestador e uma firma tomadora pode revelar informações sobre a qualidade de crédito da firma. Entretanto, trabalhos teóricos preveem diferentes resultados do efeito do relacionamento bancário sobre a taxa de juros e volume ofertado do empréstimo. De acordo com Diamond (1991) e outros, se o relacionamento bancário for revelar a todos os credores a qualidade de crédito da firma, espera-se como efeitos o aumento do volume dos empréstimos e redução na taxa de juros. Por outro lado, se o relacionamento bancário revelar as informações de crédito da firma apenas para o fornecedor principal, então se pode não ter os efeitos de aumento do volume e redução na taxa de juros. Este trabalho demonstra empiricamente quais são os efeitos das informações públicas e privadas geradas pelo relacionamento bancário no montante do empréstimo e na taxa de juros cobrada pelas instituições financeiras para as firmas. Usamos como medida de informação pública o tempo de relacionamento entre o banco e tomador, que pode ser encontrado em bureaux externos como Serasa Experian e Serviço Central de Proteção ao Crédito (SCPC) ou no Sistema de Informação do Banco Central (SISBACEN). Usamos como modelo de informação privada medidas que indicam o pagamento do débito em atraso por parte do tomador, o qual é de conhecimento apenas de cada credor. De acordo com a teoria, espera-se que a informação pública de tempo de relacionamento bancário indicará a qualidade do credor e resultará em maior volume de empréstimo e taxa de juros menores. As informações privadas sobre pagamentos em atraso, por ser exclusiva do credor principal, não terão efeitos sobre o montante do empréstimo e sobre a taxa de juros. No teste empírico, foram analisados dois mil setecentos e oitenta e cinco empréstimos do produto capital de giro concedidos a cinquenta e três empresas, fornecidos por uma instituição financeira do Estado do Espírito Santo. Utilizando o modelo econométrico dados em painel com efeito fixo de firma, encontramos que o tempo de relacionamento bancário é positivamente correlacionado ao valor do principal do empréstimo e é negativamente correlacionado ao spread bancário. Ambos os efeitos são estatisticamente significantes ao nível de 5,00%. Resultados similares ao encontrado por Berger e Udell (1995). Os resultados mostram que um relacionamento duradouro entre firmas e instituições financeiras reduz a assimetria de informação, gerando benefícios para as firmas. Para testar o feito da informação privada, foram utilizadas informações de atraso das firmas com a instituição financeira. Esses dados foram usados internamente, não divulgados em bureaux de crédito. As variáveis testadas foram número de parcelas pagas em atraso no mês anterior, a soma das parcelas pagas em atraso, flag se já efetuou pagamento em atraso e meses desde o último pagamento em atraso. Não têm efeito as informações privadas sobre o spread e o valor do principal do empréstimo. Resultados similares aos encontrados por Sharpe (1990).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper evaluates how information asymmetry affects the strength of competition in credit markets. A theory is presented in which adverse selection softens competition by decreasing the incentives creditors have for competing in the interest rate dimension. In equilibirum, although creditors compete, the outcome is similar to collusion. Three empirical implications arise. First, interest rate should respond asymmetrically to changes in the cost of funds: increases in cost of funds should, on average, have a larger effect on interest rates than decreases. Second, aggressiveness in pricing should be associated with a worseing in the bank level default rates. Third, bank level default rates should be endogenous. We then verify the validity of these three empirical implications using Brazilian data on consumer overdraft loans. The results in this paper rationalize seemingly abnormallly high interest rates in unsecured loans.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The intent of this paper is to provide a practitioners insight into the present and foreseeable future of problem of transaction cost economics related to culture and business etiquette that may increase the of complexity of business communication. We will also explore whether it impacts participant's mindsets regarding opportunistic or passive aggressive behavior. We will study the role of culture, ethics, information asymmetry, and legal systems regarding their importance towards the business contracts and lack of knowledge in local environments. We will make connections to contract theory strategies and objectives and recommend business practices. Furthermore, economic theory explores the role of the impossibility of the perfect contract. Historical and present day operational factors are examined for the determination of forward-looking contract law indications worldwide. This paper is intended provide a practitioners view with a global perspective of a multinational, mid-sized and small corporations giving consideration in a non-partisan and non-nationalistic view, yet examines the individual characteristics of the operational necessities and obligations of any corporation. The study will be general, yet cite specific articles to each argument and give adequate consideration to the intricacies of the global asymmetry of information. This paper defends that corporations of any kind and size should be aware of the risk of international business etiquette and cultural barriers that might jeopardize the savings you could obtain from engaging international suppliers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Introduction: The aim of this study was to evaluate craniofacial asymmetry by using 2-dimensional (2D) poster-oanterior cephalometric images, 3-dimensional cone-beam computed tomography (CBCT), and physical measurements (gold standard). Methods: Ten dry human skulls were assessed, and radiopaque markers were placed on 17 skeletal landmarks. Twenty linear measurements were taken on each side to compare the right and left sides and to compare these measurements with the physical measurements made with a digital caliper. To acquire the 2D posteroanterior radiographs, an Extraoral Phosphor Storage Plate (Air Techniques, Chicago, Ill) was used as the image receptor with a Eureka x-ray-Duocon Machlett unit (Machlett Laboratores, Chicago, Ill). Three-dimensional imaging data were acquired from a CB MercuRay (Hitachi Medical, Tokyo, Japan). Results: on average, the right side was larger than the left for most of the 20 distances evaluated in the digital 2D and the CBCT images, and there was poor agreement between the digital 2D images and the physical measurements (kappa = 0.0609) and almost perfect agreement (kappa = 0.92) between the CBCT and physical measurements when individual measurements were considered. Conclusions: Human skulls, with no apparent asymmetry, had some differences between the right and left sides, with dominance for the right side but with no clinical significance. CBCT can better evaluate craniofacial morphology when compared with digital 2D images. (Am J Orthod Dentofacial Orthop 2011; 139: e523-e531)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We establish the bridge between the commonly used Nabetani-Ogaito-Sato-Kishimoto (NOSK) formula for the asymmetry parameter a(Lambda) in the Lambda p -> np emission of polarized hypernuclei, and the shell-model (SM) formalism for finite hypernuclei. We demonstrate that the s-wave approximation leads to a SM formula for a(Lambda) that is as simple as the NOSK one and that reproduces the exact results for (5)(Lambda)He and (12)(Lambda)C better than initially expected. The simplicity achieved here is indeed remarkable. The new formalism makes the theoretical evaluation of a(Lambda) more transparent and explains clearly why the one-meson exchange model is unable to account for the experimental data of (5)(Lambda)He.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A calculational scheme is developed to evaluate chiral corrections to properties of composite baryons with composite pions. The composite baryons and pions are bound states derived from a microscopic chiral quark model. The model is amenable to standard many-body techniques such as the BCS and random phase approximation formalisms. An effective chiral model involving only hadronic degrees of freedom is derived from the macroscopic quark model by projection onto hadron states. Chiral loops are calculated using the effective hadronic Hamiltonian. A simple microscopic confining interaction is used to illustrate the derivation of the pion-nucleon form factor and the calculation of picnic self-energy corrections to the nucleon and Delta (1232) masses.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We report the first direct observation of the strange b baryon Xi(-)(b)(Xi) over bar (+)(b)). We reconstruct the decay Xi(-)(b)-->J/psi Xi(-), with J/psi-->mu(+)mu(-), and Xi(-)-->Lambda pi(-)-->p pi(-)pi(-) in p (p) over bar collisions at root s = 1.96 TeV. Using 1.3 fb(-1) of data collected by the D0 detector, we observe 15.2 +/- 4.4(stat)(-0.4)(+1.9)(syst) Xi(-)(b) candidates at a mass of 5.774 +/- 0.011(stat) +/- 0.015(syst) GeV. The significance of the observed signal is 5.5 sigma, equivalent to a probability of 3.3 x 10(-8) of it arising from a background fluctuation. Normalizing to the decay Lambda(b)-->J/psi Lambda, we measure the relative rate sigma(Xi(-)(b))xB(Xi(-)(b)-->J/psi Xi)/ sigma(Lambda(b))xB(Lambda(b)-->J/psi Lambda) = 0.28 +/- 0.09(stat)(-0.08)(+0.09)(syst).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We have performed the first direct measurement of the time-integrated flavor untagged charge asymmetry in semileptonic B-s(0) decays A(SL)(s,unt) by comparing the decay rate of B-s(0) -> mu(+) D-s(-) nu X, where D-s(-) -> phi pi(-) and phi -> K+K-, with the charge-conjugate (B) over bar (0)(s) decay rate. This sample was selected from 1: 3 fb(-1) of data collected by the D0 experiment in run II of the Fermilab Tevatron collider. We obtain A(SL)(s,unt) = [1.23 +/- 0.97(stat) +/- 0.17(syst)] x 10(-2). Assuming that Delta m(s)/(Gamma) over bar (s) >> 1, this result can be translated into a measurement of the CP-violating phase in B-s(0) mixing: Delta Gamma(s)/Delta m(s) tan phi(s) = [2.45 +/- 1.93(stat) +/- 0.35(syst)] x 10(-2).