Heat Transfer in MHD Flow over A Stretching Sheet with Velocity and Thermal Slip Condition

The present work is concerned with the effects of surface slip conditions and thermal on an electrically conducting fluid over a non-isothermal stretching surface in the presence of a uniform transverse magnetic field. Similarity transformation is used to transform the partial differential equations describing the problem into a system of nonlinear ordinary differential equations which is solved analytically. The effects of various parameters on the velocity and temperature profiles as well as on the local skin-friction and the local Nusselt number are discussed in detail and displayed through graphs. Keywords: MHD; Heat transfer; Slip conditions, Kumer’s function, Similarity transformation

Mixed Convection Heat Transfer of MHD Flow Due to Permeable Sheet: An Analytical Solution

In this paper we investigate the analytical solution for MHD flow and heat transfer of electrically conducting fluid due to vertical starching surface. Here the diffusion thermo (Dufour) and thermal diffusion (Soret) effects are considered. It is shown that the porosity, magnetic, convection, concentrationand buoyancy effects can be combined with a new parameter called porous- magneto-convection-concentration parameters .The effect of physical parameter influencing the flow and heat transfer are studied and results are plotted and discussed. Keywords: Heat Transfer, Porous-Magneto-Convection-Concentration parameter, Buoyancy, Soret,  Dufour,  Lewis

Diversidad de anfibios: su importancia en los ecosistemas y declinación de poblaciones

En este capítulo se abordan diferentes aspectos relacionados con los anfibios respondiendo a preguntas tales como qué son los anfibios, cuáles son sus características principales y cuál es su importancia en los ecosistemas. Además se incluyen referencias acerca de su diversidad en Argentina, principalmente en las provincias de Corrientes, Chaco y Formosa y comentarios sobre los principales factores relacionados con la declinación global de anfibios.Fil: Cespedez, Jorge Abel. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología. Laboratorio de Herpetología; ArgentinaFil: Zaracho, Victor Hugo. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología. Laboratorio de Herpetología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Álvarez, B.B.. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología. Laboratorio de Herpetología; ArgentinaFil: Colombo, M.C.. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología. Laboratorio de Herpetología; Argentin

Brane-Antibrane Systems at Finite Temperature and Phase Transition near the Hagedorn Temperature

In order to study the thermodynamic properties of brane-antibrane systems, we compute the finite temperature effective potential of tachyon T in this system on the basis of boundary string field theory. At low temperature, the minimum of the potential shifts towards T=0 as the temperature increases. In the D9-antiD9 case, the sign of the coefficient of |T|^2 term of the potential changes slightly below the Hagedorn temperature. This means that a phase transition occurs near the Hagedorn temperature. On the other hand, the coefficient is kept negative in the Dp-antiDp case with p <= 8, and thus a phase transition does not occur. This leads us to the conclusion that only a D9-antiD9 pair and no other (lower dimensional) brane-antibrane pairs are created near the Hagedorn temperature. We also discuss a phase transition in NS9B-antiNS9B case as a model of the Hagedorn transition of closed strings.Comment: 28 pages, 3 figures, minor errors correcte

Estado de nutrição de pomares de pessegueiro na região da Beira Interior

A Beira Interior possui a principal área portuguesa de produção de pêssego (1803 ha) e possui também o know-how sobre esta cultura, existindo a única indicação geográfica protegida de pêssego do país – IGP pêssego da Cova da Beira, canais de comercialização, assistência técnica e ações de I&D. Paralelamente existe uma constante procura de conhecimento e inovação por parte dos produtores de modo a maximizarem o rendimento da cultura. Sendo a fertilização uma técnica com baixo peso nos custos de produção, aproximadamente 8%, é frequente existirem excessos para atingir produções mais elevadas. A fertilização reflete-se na disponibilidade de nutrientes e no estado de nutrição dos pomares que, com a rega, é determinante para o equilíbrio das plantas, para o seu vigor e produção e para a resistência a pragas ou doenças. A monitorização, desde a instalação, de 28 pomares localizados na região da Beira Interior, permitiu avaliar o estado de nutrição ao 3º ciclo vegetativo. Os resultados indicam que apesar do solo apresentar maioritariamente níveis altos de P e K, 45% dos pomares apresentaram teores foliares de K inferiores ao intervalo de referência. Também o teor de Zn se encontra em níveis inferiores a esse intervalo em 50% dos pomares.info:eu-repo/semantics/publishedVersio

Finite Temperature Systems of Brane-Antibrane on a Torus

In order to study the thermodynamic properties of brane-antibrane systems in the toroidal background, we compute the finite temperature effective potential of tachyon T in this system on the basis of boundary string field theory. We first consider the case that all the radii of the target space torus are about the string scale. If the Dp-antiDp pair is extended in all the non-compact directions, the sign of the coefficient of |T|^2 term of the potential changes slightly below the Hagedorn temperature. This means that a phase transition occurs near the Hagedorn temperature. On the other hand, if the Dp-antiDp pair is not extended in all the non-compact directions, the coefficient is kept negative, and thus a phase transition does not occur. Secondly, we consider the case that some of the radii of the target space torus are much larger than the string scale and investigate the behavior of the potential for each value of the radii and the total energy. If the Dp-antiDp pair is extended in all the non-compact directions, a phase transition occurs for large enough total energy.Comment: 23 pages, 3 figures, minor errors corrected, version to appear in JHE

Formation and Evolution of Supermassive Black Holes

The correlation between the mass of supermassive black holes in galaxy nuclei and the mass of the galaxy spheroids or bulges (or more precisely their central velocity dispersion), suggests a common formation scenario for galaxies and their central black holes. The growth of bulges and black holes can commonly proceed through external gas accretion or hierarchical mergers, and are both related to starbursts. Internal dynamical processes control and regulate the rate of mass accretion. Self-regulation and feedback are the key of the correlation. It is possible that the growth of one component, either BH or bulge, takes over, breaking the correlation, as in Narrow Line Seyfert 1 objects. The formation of supermassive black holes can begin early in the universe, from the collapse of Population III, and then through gas accretion. The active black holes can then play a significant role in the re-ionization of the universe. The nuclear activity is now frequently invoked as a feedback to star formation in galaxies, and even more spectacularly in cooling flows. The growth of SMBH is certainly there self-regulated. SMBHs perturb their local environment, and the mergers of binary SMBHs help to heat and destroy central stellar cusps. The interpretation of the X-ray background yields important constraints on the history of AGN activity and obscuration, and the census of AGN at low and at high redshifts reveals the downsizing effect, already observed for star formation. History appears quite different for bright QSO and low-luminosity AGN: the first grow rapidly at high z, and their number density decreases then sharply, while the density of low-luminosity objects peaks more recently, and then decreases smoothly.Comment: 31 pages, 13 figures, review paper for Astrophysics Update

Exploring flavor structure of supersymmetry breaking from rare B decays and unitarity triangle

We study effects of supersymmetric particles in various rare B decay processes as well as in the unitarity triangle analysis. We consider three different supersymmetric models, the minimal supergravity, SU(5) SUSY GUT with right-handed neutrinos, and the minimal supersymmetric standard model with U(2) flavor symmetry. In the SU(5) SUSY GUT with right-handed neutrinos, we consider two cases of the mass matrix of the right-handed neutrinos. We calculate direct and mixing-induced CP asymmetries in the b to s gamma decay and CP asymmetry in B_d to phi K_S as well as the B_s--anti-B_s mixing amplitude for the unitarity triangle analysis in these models. We show that large deviations are possible for the SU(5) SUSY GUT and the U(2) model. The pattern and correlations of deviations from the standard model will be useful to discriminate the different SUSY models in future B experiments.Comment: revtex4, 36 pages, 10 figure

Higgs and neutrino sector, EDM and epsilon_K in a spontaneously CP and R-parity breaking supersymmetric model

We construct an extension of the supersymmetric standard model where both CP symmetry and R-parity are spontaneously broken. We study the electroweak symmetry breaking sector of the model and find minima consistent with the experimental bounds on Higgs boson masses. Neutrino masses and mixing angles are generated through both seesaw and bilinear R-parity violation. We show that the hierarchical mass pattern is obtained, and mixings are consistent with measured values. Due to the spontaneous CP and R-parity violation, the neutrino sector is CP violating, and we calculate the corresponding phase. We further restrict the parameter space to agree with the limits on the electric dipole moment of the neutron. Finally, we study the CP violation parameter epsilon_K in the kaon system and show that we obtain results consistent with the experimental value.Comment: 13 pages, 7 figures, submitted to EPJ

Model confidence sets and forecast combination: an application to age-specific mortality

Background: Model averaging combines forecasts obtained from a range of models, and it often produces more accurate forecasts than a forecast from a single model. Objective: The crucial part of forecast accuracy improvement in using the model averaging lies in the determination of optimal weights from a finite sample. If the weights are selected sub-optimally, this can affect the accuracy of the model-averaged forecasts. Instead of choosing the optimal weights, we consider trimming a set of models before equally averaging forecasts from the selected superior models. Motivated by Hansen et al. (2011), we apply and evaluate the model confidence set procedure when combining mortality forecasts. Data & Methods: The proposed model averaging procedure is motivated by Samuels and Sekkel (2017) based on the concept of model confidence sets as proposed by Hansen et al. (2011) that incorporates the statistical significance of the forecasting performance. As the model confidence level increases, the set of superior models generally decreases. The proposed model averaging procedure is demonstrated via national and sub-national Japanese mortality for retirement ages between 60 and 100+. Results: Illustrated by national and sub-national Japanese mortality for ages between 60 and 100+, the proposed model-average procedure gives the smallest interval forecast errors, especially for males. Conclusion: We find that robust out-of-sample point and interval forecasts may be obtained from the trimming method. By robust, we mean robustness against model misspecification