Comparison of the moments of the X(max) distribution predicted by different cosmic ray shower simulation models

In this paper we study the depth at which a cosmic ray shower reaches its maximum (Xmax) as predicted by Monte Carlo simulation. The use of Xmax in the determination of the primary particle mass can only be done by comparing the measured values with simulation predictions. For this reason it is important to study the differences between the available simulation models. We have done a study of the first and second moments of the X max distribution using the Corsika and Conex programs. The study was done with high statistics in the energy range from 1017 to 10 20.4 eV. We focus our analysis in the different implementations of the hadronic interaction models Sibyll2.1 and QGSJetII in Corsika and Conex. We show that the predictions of the «Xmax» and RMS(X max) depend slightly on the combination of simulation program and hadronic interaction model. Although these differences are small, they are not negligible in some cases (up to 5 g/cm2 for the worse case) and they should be considered as a systematic uncertainty of the model predictions for «Xmax» and RMS(Xmax). We have included a table with the suggested systematic uncertainties for the model predictions. Finally, we present a parametrization of the Xmax distribution as a function of mass and energy according to the models Sibyll2.1 and QGSJetII, and showed an example of its application to obtain the predicted Xmax distributions from cosmic ray propagation models. © 2013 Elsevier B.V. All rights reserved.Carlos Jose Todero Peixoto, Vitor de Souza, Jose Alfredo Bellid

New Supergravity Backgrounds Dual to N=1 SQCD-like Theories with N_f=2N_c

We present new supergravity backgrounds generated by N_c D5-branes, wrapping the S^2 of the resolved conifold, in the presence of N_f = 2 N_c smeared flavor D5-branes. The smearing allows us to take their backreaction on the geometry into account. We discuss the consistency, stability, and supersymmetry of these types of setups. We find near horizon geometries that we expect to be supergravity duals of SQCD-like theories with N_f= 2N_c. From these backgrounds we numerically extract rectangular Wilson loops and beta functions of the dual field theory for the regime where our approximations are valid.Comment: 22+24 pages, 17 figures, Figure 12 replace

Supergravity Radiative Effects on Soft Terms and the μ\mu Term

We compute quadratically divergent supergravity one-loop effects on soft supersymmetry-breaking parameters and the $\mu$ term in generic hidden sector supergravity models. These effects can significantly modify the matching condition for soft parameters at the Planck scale and also provide several new sources of the $\mu$ term which are naturally of order the weak scale. We also discuss some phenomenological implications of these effects, particularly the violation of the scalar mass universality which may lead to dangerous FCNC phenomena, and apply the results to superstring effective supergravity models.Comment: 12 pages, REVTEX. One reference is adde

The First Science Results from SPHERE: Disproving the Predicted Brown Dwarf around V471 Tau

Variations of eclipse arrival times have recently been detected in several post common envelope binaries consisting of a white dwarf and a main sequence companion star. The generally favoured explanation for these timing variations is the gravitational pull of one or more circumbinary substellar objects periodically moving the center of mass of the host binary. Using the new extreme-AO instrument SPHERE, we image the prototype eclipsing post-common envelope binary V471 Tau in search of the brown dwarf that is believed to be responsible for variations in its eclipse arrival times. We report that an unprecedented contrast of 12.1 magnitudes in the H band at a separation of 260 mas was achieved, but resulted in a non-detection. This implies that there is no brown dwarf present in the system unless it is three magnitudes fainter than predicted by evolutionary track models, and provides damaging evidence against the circumbinary interpretation of eclipse timing variations. In the case of V471 Tau, a more consistent explanation is offered with the Applegate mechanism, in which these variations are prescribed to changes in the quadrupole moment within the main-sequence sta

Gravity duals of 2d supersymmetric gauge theories

We find new supergravity solutions generated by D5-branes wrapping a four-cycle and preserving four and two supersymmetries. We first consider the configuration in which the fivebranes wrap a four-cycle in a Calabi-Yau threefold, which preserves four supersymmetries and is a gravity dual to the Coulomb branch of two-dimensional gauge theories with N=(2,2) supersymmetry. We also study the case of fivebranes wrapping a co-associative four-cycle in a manifold of G_2-holonomy, which provides a gravity dual of N=(1,1) supersymmetric Yang-Mills theory in two dimensions. We also discuss the addition of unquenched fundamental matter fields to these backgrounds and find the corresponding gravity solutions with flavor brane sources.Comment: 34 pages + appendices; v2: minor improvement

Education for Sustainable Development: An Exploratory Survey of a Sample of Latin American Higher Education Institutions

Education for sustainable development (ESD) is defined as the knowledge and skills ‘needed to work and live in a way that safeguards environmental, social and economic wellbeing, both in the present and for future generations’. Skills for sustainable development include critical thinking, creative thinking, systems thinking and leadership. Over the last decades, there has been efforts across the world to embed ESD into the curriculum. In European Union (EU) countries, some higher education have made efforts to align education strategies with international and national ESD frameworks. A cursory review of the literature seems to indicate that dissemination and implementation of the international ESD frameworks in Latin America has been slow and sporadic. Although there are some signs to implement ESD into curricula of countries such as Brazil and Colombia, these practices have not been substantial or have not permeated higher education sustainable development strategies. This paper aims to explore the developments of ESD in Latin America. As a first step to explore these developments, it intends to survey and map the current ESD processes in eight higher education institutions of four Latin American Countries: Chile, Colombia, Mexico and Peru. The paper also aims to compare ESD developments with some leading EU higher education institutions in ESD with the view to develop a dialogue between the two regions. These will lead to strategies in which ESD processes can be adopted/adapted with benefits in both directions; it will also create, foster and develop mechanisms that will ensure a sustainable culture of ESD in higher education in both regions. Results of the exploratory survey of a sample of higher education institutions in Latin America are reported

Recent Heavy-Flavor results at STAR

We present the recent results on non-photonic electron (NPE) yields from RHIC run8 p+p collisions. The $e/\pi$ ratio as a function of $p_T$ in run8 with a factor of 10 reduction of the inner detector material at STAR is found to be consistent with those results from run3 taking into account the NPE from charm leptonic decay and the difference of photonic electron yield from photon conversion in detector material. \Jpsi spectra in \pp and \cucu collisions at \sNN = 200 GeV with high sampled luminosity \Jpsi spectrum at high-\pT follows $x_T$ scaling, but the scaling is violated at low \pT. $J/\psi$-hadron correlations in \pp collisions are studied to understand the \Jpsi production mechanism at high $p_T$. We observed an absence of charged hadrons accompanying \Jpsi on the near-side, in contrast to the strong correlation peak in the di-hadron correlations. This constrains the $B$-meson contribution and jet fragmentation to inclusive \Jpsi to be ${}^{<}_{\sim}17$. Yields in minimum-bias \cucu collisions are consistent with those in \pp collisions scaled by the underlying binary nucleon-nucleon collisions in the measured \pT range. Other measurements and future projects related to heavy-flavors are discussed.Comment: 8 pages 4 figures, proceedings of the International Conference on Strangeness in Quark Matter 2008 - Beijing, China, Oct. 6-10, 200

The Non-SUSY Baryonic Branch: Soft Supersymmetry Breaking of N=1 Gauge Theories

We study a non-supersymmetric deformation of the field theory dual to the baryonic branch of Klebanov-Strassler. Using a combination of analytical (series expansions) and numerical methods we construct non-supersymmetric backgrounds that smoothly interpolate between the desired UV and IR behaviors. We calculate various observables of the field theory and propose a picture of soft breaking by gaugino masses that is consistent with the various calculations on the string side.Comment: 32 pages plus many appendixes. One figur

Control of naturally infested peaches (Prunus persica) by mediterranean fruit fly (Ceratitis capitata) through the use of gamma radiation

Determination of the dose of gamma radiation to disinfest peaches, Prunus pérsica infested with larvae of Ceratitis capitata (Wied., 1824) was made. Fruits were collected in the field, each one holding about nine larvae of the last instar of the fruit-fly. The fruits were irradiated with Cobalt-60 gamma radiation source at the following doses: 0 (control), 25, 50, 100, 200, 400, 600, 800, 1000 and 1200 Gy; at a dose rate of 58 Gy per minute. After irradiation the fruits were kept in a climatic chamber with the temperature adjusted between 23 and 27&deg;C, and relative humidity between 65 and 75 percent, until the larvae left the fruits and were transformed into pupae and adults. It was concluded that the lethal dose of gamma radiation for larvae at the last instar, in naturally infested peaches, was 600 Gy and the dose of 50 Gy inhibited completely the emergency of adults.Determinou-se a dose desinfestante de radiações gama para pêssegos, Prunus persica, infestados com larvas da mosca do Mediterrâneo, Ceratitis capitata. Utilizaram-se frutas de procedência conhecida no campo fazendo-se uma amostragem prévia, constatando-se que cada fruta continha em média nove larvas do último ínstar da mosca praga. As frutas foram irradiadas em uma fonte de Cobalto-60 com as seguintes doses de radiação gama: 0 (test.), 25, 50, 100, 200, 400, 600, 800, 1000 e 1200 Gy, sob uma taxa de 58 Gy por minuto. Após a irradiação as frutas foram colocadas em câmaras climatizadas com a temperatura variando entre 23 e 27&deg;C e a umidade relativa variando entre 65 e 75%. Aguardou-se que as larvas deixassem as frutas e se transformassem em pupas e adultos. A dose letal para larvas, pelos resultados obtidos no experimento, concluiu-se ser de 600 Gy. A dose letal para pupas provenientes de larvas irradiadas dentro das frutas foi de 50 Gy, impedindo totalmente a emergência de adultos

Safety and Health in Mining

In the history of the mining sector, in its beginnings it faced very high levels of risks both safety and health. The data are limited to serious accidents, and these are mainly associated with falls from land, transport and machinery. Analysis of these data suggests that the leading causes of death tend to be the same as those of serious injuries, while disasters have a different profile. Over the past decade, mining disasters have been associated with explosions due to flammable gases, a fire on a conveyor belt, a flood of mud and water, and rock outbursts. Mandatory compliance with a company's safety, health and environmental regulations is a minimum and can be significantly improved by adding a long-term management planning and implementation process with a deeper cultural shift towards continuous improvement in safety and quality. Note that the purpose of integrating health and safety into other management systems is the need for health and safety management to be central, rather than an organizational objective