Autonomous University of Zacatecas
Zacatecas, Mexico

The Universidad Autónoma de Zacatecas is a Mexican public research university based in the city of Zacatecas, Zacatecas, but with several campuses across the state. It is considered both the most prestigious and most important college in the State. According to mexican business and economics newspaper El Economista the UAZ is among the 30 best mexican universities. Wikipedia.

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Lee X.-H.,National Central University | Moreno I.,Autonomous University of Zacatecas | Sun C.-C.,National Central University
Optics Express | Year: 2013

An efficient LED lamp that illuminates the street with high quality is presented. The luminaire shows high optical efficiency, high optical utilization factor, low glare, and illuminates the street with high uniformity. The concept is simple but effective: a cluster of LEDs with TIR lenses are put inside a reflective box, which is covered with a microlens sheet; the reflective cavity improves efficiency by light recycling; each TIR lens collimates the LED light for the microlens array; and the microlens sheet uniformly distributes light only into the street. We verify its feasibility by Monte Carlo ray-tracing for the main types of road lighting arrangements: central, zigzag, and single-side pole positions. © 2013 Optical Society of America.

Gutierrez-Rodriguez A.,Autonomous University of Zacatecas
European Physical Journal C | Year: 2011

We obtain limits on the anomalous magnetic and electric dipole moments of the Vτ through the reaction e+e‑‑ -> vvγ and in the framework of a 331 model. We consider initial-state radiation, and neglect W and photon exchange diagrams. The results are based on the data reported by the L3 Collaboration at LEP, and compare favorably with the limits obtained in other models, complementing previous studies on the dipole moments. © Springer-Verlag/Società Italiana di Fisica 2011.

Ezquerro-Canete A.,Autonomous University of Zacatecas
Journal of Agrarian Change | Year: 2016

This paper challenges the recent hailing of agricultural biotechnology as a panacea for food insecurity and rural poverty in countries of the global South. Based on an empirical investigation of the neoliberal soy regime in Paraguay, I document how the profound transformation of this country's agricultural mode of production over the past two decades, spurred by the neoliberal restructuring of agriculture and the biorevolution, has jeopardized rural livelihoods. In particular, I demonstrate how the transgenic soyization of Paraguay's agriculture has led to an increased concentration of landholdings, as well as the displacement and disempowerment of peasants and rural labourers who have been rendered surplus to the requirements of agribusiness capital. At the same time, the consolidation of this new agro-industrial model has fostered a growing dependence on agrochemicals that compromise environmental quality and human health. Thus, I argue, a development policy based on industrial monocropping of genetically modified (GM) soy is inappropriate, unsustainable and unethical. © 2016 John Wiley & Sons Ltd.

Moreno I.,Autonomous University of Zacatecas
Optics Letters | Year: 2010

Assessing how uniform the light distribution is throughout an illuminated target is important in many applications, but traditional methods do not quantify the variability of illuminance as the human visual system (HVS) does. Considering that most light patterns are intended for humans, I propose a simple metric that assesses the uniformity in a similar way as humans do. This uniformity indicator is based on the fact that the HVS is highly sensitive to spatial frequencies and then uses the Fourier transform and the contrast sensitivity function of the HVS in a practical way. © 2010 Optical Society of America.

Gutierrez-Rodriguez A.,Autonomous University of Zacatecas
Modern Physics Letters A | Year: 2010

From the total cross-section for the reaction +e- → τ+τ-γ at the Z1 pole and in the framework of a simplest little Higgs model (SLHM), we get a limit on the characteristic energy scale of the model f, f ≥ 5.4 TeV, which in turn induces bounds on the electromagnetic and weak dipole moments of the taulepton. Our bounds on the electromagnetic moments are consistent with the bounds obtained by the L3 and OPAL collaborations for the reaction +e - → τ+τ-γ. We also obtained bounds on the tau weak dipole moments which are consistent with the bounds obtained recently by the DELPHI and ALEPH collaborations from the reaction e+e- → τ+τ-. © 2010 World Scientific Publishing Company.

Moreno I.,Autonomous University of Zacatecas
Optics Letters | Year: 2012

An array of spatially distributed light-emitting diodes (LEDs) can produce an illumination pattern that approaches an image by individually modulating each LED. In this letter, I analyze the first-order design of such systems in order to achieve the best match between the illumination distribution and a desired image. In particular, simple formulas are given for the optimal number of LEDs, working distance, array size, and LED beam pattern. The analysis developed here may be applied to the design of LED systems such as architecture lighting, energy-efficient lighting, backlight local dimming for displays, and structured illumination microscopy with micro-LED arrays. © 2012 Optical Society of America.

Vishwakarma R.G.,Autonomous University of Zacatecas
Research in Astronomy and Astrophysics | Year: 2013

As we now know, there are at least two major difficulties with general relativity (GR). The first one is related to its incompatibility with quantum mechanics, in the absence of a consistent, widely accepted theory that combines the two theories. The second problem is related to the requirement of the dark sectors¡inflaton, dark matter and dark energy by the energy-stress tensor, which are needed to explain a variety of astronomical and cosmological observations. Research has indicated that the dark sectors themselves do not have any non-gravitational or laboratory evidence. Moreover, the dark energy poses, in addition, a serious confrontation between fundamental physics and cosmology. Guided by theoretical and observational evidences, we are led to an idea that the source of gravitation and its manifestation in GR should be modified. The result is in striking agreement with not only the theory, but also the observations, without requiring the dark sectors of the standard approach. Additionally, it provides natural explanations to some unexplained puzzles.

Moreno I.,Autonomous University of Zacatecas
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2010

A light cone efficiently transports, distributes, and concentrates the incoming radiation. I derive a formula for the spatial irradiance (or illuminance) distribution at the exit aperture of a tapered light pipe. The theory is demonstrated by Monte Carlo ray-tracing for lightpipes with light-emitting diodes at the input face. The analysis is based on the addition of the radiation patterns of the multiple virtual sources that, as in a three-dimensional kaleidoscope, are seen through a tapered light tube. Given its explicit dependence on the structural and optical parameters, this analysis may be a useful tool in the development and application of light cones. © 2010 Optical Society of America.

Gutierrez-Rodriguez A.,Autonomous University of Zacatecas
Advances in High Energy Physics | Year: 2014

We study the sensitivity on the anomalous magnetic and electric dipole moments of the τ -neutrino at a high-energy and high-luminosity linear electron positron collider, such as the ILC or CLIC, through the reaction e + e- → vv̄γ. We obtain limits on the dipole moments at the future linear colliders energies. For integrated luminosities of 500 fb-1 and center of mass energies between 0.5 and 3 TeV, the future e+ e- colliders may improve the existing limits by two or three orders of magnitude. © 2014 A. Gutiérrez- Rodríguez.

Vishwakarma R.G.,Autonomous University of Zacatecas
Frontiers of Physics | Year: 2014

Despite a century-long effort, a proper energy-stress tensor of the gravitational field, could not have been discovered. Furthermore, it has been discovered recently that the standard formulation of the energy-stress tensor of matter, suffers from various inconsistencies and paradoxes, concluding that the tensor is not consistent with the geometric formulation of gravitation [Astrophys. Space Sci., 2009, 321: 151; Astrophys. Space Sci., 2012, 340: 373]. This perhaps hints that a consistent theory of gravitation should not have any bearing on the energy-stress tensor. It is shown here that the so-called "vacuum" field equations Rik = 0 do not represent an empty spacetime, and the energy, momenta and angular momenta of the gravitational and the matter fields are revealed through the geometry, without including any formulation thereof in the field equations. Though, this novel discovery appears baffling and orthogonal to the usual understanding, is consistent with the observations at all scales, without requiring the hypothetical dark matter, dark energy or inflation. Moreover, the resulting theory circumvents the long-standing problems of the standard cosmology, besides explaining some unexplained puzzles. © 2014 Higher Education Press and Springer-Verlag Berlin Heidelberg.

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