Border X-ing

The sun out-stretched its bright arms in an embrace with the mesquite trees that beckoned upwards. The wind greeted the clothes drying upon delicate wire while my mother meticulously placed white towels in the light and the jeans under the shade of the Arizona Ash. The washboard sits upright in the bucket full of suds and other assorted laundry. Inside the shed there is both a working dryer and washer only a few years old, but she has chosen to do this chore outside. Here she can close her eyes and be back in Mexico with the dry heat and the dusty wind hitting against the houses of colorful concrete walls. She senses the animals of the ranch pecking at the maize that has been long picked since the harvest. She hears the commotion of the bar-b-que that is smoking next door at Tia Alaida’s house, a world that I have only visited a few times, never quite experiencing it as deeply as she. [excerpt

Layered Perovskite Oxides: Synthesis, Structural Characteristics and Electrical Properties

[ES] Los óxidos tipo Aurivillius presentan una estructura perovsquita laminar, constituida por el apilamiento de capas tipo perovsquita [An-1BnO3n+1] y capas [Bi2O2]. Se estudia la estabilidad estructural de estos óxidos en función de los radios iónicos de los cationes que participan en ellos y de la influencia de pares electrónicos libres (ns2) asociados a los cationes que constituyen la capa de bismuto. Se han puesto a punto métodos alternativos que permiten optimizar las condiciones de síntesis y abaratar los sistemas de producción, como el de activación mecanoquímica. Se muestran ejemplos de fases de Aurivillius, en los que se pone de manifiesto las propiedades ferro-piezoeléctricas y de conductividad iónica de estos materiales. La mesoestructura y propiedades ferro-piezoeléctricas se ven netamente mejoradas gracias a la utilización del método mecanoquímico. Se demuestra que la Tc es fuertemente dependiente de la estructura cristalina, la cual depende del tamaño y naturaleza de los cationes que constituyen cada fase. La conductividad iónica en estos materiales se produce por salto de iones oxígeno entre posiciones ocupadas y vacantes en la capa perovsquita, mientras que es insensible a la presencia de vacantes aniónicas en la capa de bismuto. Tratamientos mecánicos permiten el reciclado de ciertos materiales deteriorados en ciclos térmicos.[EN] The Aurivillius type oxides show a layered perovskite structure, built up by the interleaved of perovskite [An-1BnO3n+1] and [Bi2O2] sheets. The structural stability of these oxides is presented as a function of the ionic radii and lone pair of electrons (ns2) of cations. New mechanochemical activation synthesis methods have been used in order to facilitate the preparation of Aurivillius phases and to cheapen their production systems. Some Aurivillius ferro-piezoelectric and ionic conductors examples are shown. The mesostructure and ferro-piezoelectric properties are improved by processing materials from mechanochemically activated amorphous powdered precursors. Change in unit-cell volume of these materials, by means of cationic substitutions, are responsible for the changes of their Tc. Ionic conductivity in Aurivillius oxides occurs by hopping between neighboring oxygen positions within perovskite layer while ion migration within bismuth layer would have a negligible contribution. Mechanical processes can recycle some of these materials, damaged by consecutive thermal treatments.Agradecer el apoyo financiero de los proyectos MAT97-0711 y 07N/0061/1998, de la CICYT y CAM, respectivamentePeer reviewe

Critical JT Gravity

In this paper, we investigate a critical behavior of JT gravity, a model of two-dimensional quantum gravity on constant negatively curved spacetimes. Our approach involves using techniques from random maps to investigate the generating function of Weil--Petersson volumes, which count random hyperbolic surfaces with defects. The defects are weighted geodesic boundaries, and criticality is reached by tuning the weights to the regime where macroscopic holes emerge in the hyperbolic surface, namely \textit{non-generic criticality}. We analyze the impact of this critical regime on some universal features, such as its density of states. We present a family of models that interpolates between systems with $\rho_0(E)\sim\sqrt{E-E_0}$ and $\rho_0(E)\sim (E-E_0)^{3/2}$, which are commonly found in models of JT gravity coupled to dynamical end-of-the-world and FZZT branes, and give a precise definition of what this phase transition means from the random geometry point of view.Comment: 28 pages, 15 figure

Dancing Between Worlds: Afrofuturism, Hybridity, Transculturalism, and the Orixás

This research uses a multicultural lens to analyze the intersections of race and geography. It aims to acknowledge the corporeality of spiritual practices to investigate creative movement. Afrofuturism becomes a theoretical framework utilized as a space for liberation into the past, present, and future. Hybridity is adapted to examine identitdade dupla regarding national, racial, cultural, and lingual identities. The research explores Transculturalism by centering Blackness and interrogating the political powers of race in both the United States and Brazil. The physical manifestation utilizes the Black imaginary with choreography, set design, costuming, and musical composition as ideological frames for time travel and liberation. In researching the body as an archive of ancestral knowledge, movement unlocks a form of resistance in motion that otherwise wouldn’t be experienced outside of its physical embodiment

Renormalization Group Approach to the Continuum Limit of Matrix Models of Quantum Gravity with Preferred Foliation

This contribution is not intended as a review but, by suggestion of the editors, as a glimpse ahead into the realm of dually weighted tensor models for quantum gravity. This class of models allows one to consider a wider class of quantum gravity models, in particular one can formulate state sum models of spacetime with an intrinsic notion of foliation. The simplest one of these models is the one proposed by Benedetti and Henson, which is a matrix model formulation of two-dimensional Causal Dynamical Triangulations (CDT). In this paper we apply the Functional Renormalization Group Equation (FRGE) to the Benedetti-Henson model with the purpose of investigating the possible continuum limits of this class of models. Possible continuum limits appear in this FRGE approach as fixed points of the renormalization group flow where the size of the matrix acts as the renormalization scale. Considering very small truncations, we find fixed points that are compatible with analytically known results for CDT in two dimensions. By studying the scheme dependence of our results we find that precision results require larger truncations than the ones considered in the present work. We conclude that our work suggests that the FRGE is a useful exploratory tool for dually weighted matrix models. We thus expect that the FRGE will be a useful exploratory tool for the investigation of dually weighted tensor models for CDT in higher dimensions.Comment: 12 pages, 5 figure

Scale-invariant random geometry from mating of trees: a numerical study

The search for scale-invariant random geometries is central to the Asymptotic Safety hypothesis for the Euclidean path integral in quantum gravity. In an attempt to uncover new universality classes of scale-invariant random geometries that go beyond surface topology, we explore a generalization of the mating of trees approach introduced by Duplantier, Miller and Sheffield. The latter provides an encoding of Liouville Quantum Gravity on the 2-sphere decorated by a certain random space-filling curve in terms of a two-dimensional correlated Brownian motion, that can be viewed as describing a pair of random trees. The random geometry of Liouville Quantum Gravity can be conveniently studied and simulated numerically by discretizing the mating of trees using the Mated-CRT maps of Gwynne, Miller and Sheffield. Considering higher-dimensional correlated Brownian motions, one is naturally led to a sequence of non-planar random graphs generalizing the Mated-CRT maps that may belong to new universality classes of scale-invariant random geometries. We develop a numerical method to efficiently simulate these random graphs and explore their possible scaling limits through distance measurements, allowing us in particular to estimate Hausdorff dimensions in the two- and three-dimensional setting. In the two-dimensional case these estimates accurately reproduce previous known analytic and numerical results, while in the three-dimensional case they provide a first window on a potential three-parameter family of new scale-invariant random geometries.Comment: 28 pages, 16 figure

Finanzas Empresariales : Administración de las Cuentas por cobrar

El presente trabajo de investigación titulado Finanzas empresariales en la Administración de las Cuentas por cobrar, tiene como objetivo principal identificar adecuadamente la aplicación del control interno y su importancia en la administración de las cuentas por cobrar. El estudio se desarrolló a través de la investigación bibliográfica para conocer lo relacionado en la administración de las cuentas por cobrar en las finanzas empresariales, así como los métodos para el análisis financiero administrativo. Las cuentas por cobrar constituyen el crédito que la empresa concede a sus clientes a través de una cuenta abierta, para la entrega de un artículo o servicio. Con el objetivo de conservar los clientes actuales y nuevos clientes las mayorías de las empresas recurren a los ofrecimientos del crédito. La administración de las cuentas por cobrar debe ser no solamente el de cobrar con prontitud, también debe prestarse a las alternativas costos-beneficios que se presentan en los diferentes campos de las administración de estas, estos campos comprenden la determinación de las políticas de créditos, las condiciones de créditos y las políticas de cobro

Technological and functional analysis of pleistocene components from La María locality, Santa Cruz, Argentina

Fil: Cueto, Manuel. División Arqueología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Castro, Alicia Susana. División Arqueología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin

Entrepreneurs´ perceptions of success: examining differences across gender and family status

Our study examines to what extent female and male entrepreneurs differ in the way they perceive and assess entrepreneurial success, measured by extrinsic or intrinsic dimensions. Our results indicate a number of similarities between men and women entrepreneurs but also reveal interesting gender-based differences related to family status. Rather than assuming that women entrepreneurs are a homogeneous group, we found that family factors, and especially parental status, play a key role in shaping fundamentally different perceptions of entrepreneurial success amongst different types of women entrepreneurs.Entrepreneur, Gender, Children, Perception of success

Simulating Behaviours to Face up an Emergency Evacuation

Computer based models describing pedestrian behavior in an emergency evacuation play a vital role in the development of active strategies that minimize the evacuation time when a closed area must be evacuated. The reference model has a hybrid structure where the dynamics of fire and smoke propagation are modeled by means of Cellular Automata and for simulating people's behavior we are using Intelligent Agents. The model consists of two sub-models, called environmental and pedestrian ones. As part of the pedestrian model, this paper concentrates in a methodology that is able to model some of the frequently observed human?s behaviors in evacuation exercises. Each agent will perceive what is happening around, select the options that exist in that context and then it makes a decision that will reflect its ability to cope with an emergency evacuation, called in this work, behavior. We also developed simple exercises where the model is applied to the simulation of an evacuation due to a potential hazard, such as fire, smoke or some kind of collapse.Fil: Tissera, Pablo Cristian. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Departamento de Informática. Laboratorio Investigación y Desarrollo En Inteligencia Computacional; ArgentinaFil: Castro, Alicia. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Departamento de Informática. Laboratorio Investigación y Desarrollo En Inteligencia Computacional; ArgentinaFil: Printista, Alicia Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Departamento de Informática. Laboratorio Investigación y Desarrollo en Inteligencia Computacional; ArgentinaFil: Luque, Emilio. Universitat Autonoma de Barcelona; Españ