Fourier's Law in a Quantum Spin Chain and the Onset of Quantum Chaos

We study heat transport in a nonequilibrium steady state of a quantum interacting spin chain. We provide clear numerical evidence of the validity of Fourier law. The regime of normal conductivity is shown to set in at the transition to quantum chaos.Comment: 4 pages, 5 figures, RevTe

Configuración de una economía de comercio informal en Medellín

In this paper it is intended to analyze the process undergone by the city of Medellin in the configuration of an informal trade economy, based on the impact of deindustrialization and the enactment of neoliberal labor reforms. Through a bibliographic and documentary review, a historical contextualization of these factors is carried out, through which their impact is linked to the conditions of informal trade. From this study, it becomes clear that Medellin s commitment to become a services - oriented city requires to pay attention to the creation of companies and jobs with high levels of innovation and qualification, to reduce labor informality and the participation of employed persons in informal trade.Este artigo tem como objetivo analisar o processo que a cidade de Medellín viveu na configuração de uma economia de comércio informal, a partir da incidência que a desindustrialização e a promulgação de reformas trabalhistas neoliberais tiveram. Por meio de uma revisão bibliográfica e documental, realiza-se uma contextualização histórica desses fatores e relaciona-se o impacto com as condições do comércio informal. A partir dessa revisão, fica evidente que a aposta que Medellín assumiu de se converter em uma cidade de serviços requer especial atenção à geração de empresas e de empregos com altos níveis de inovação e de qualificação, com o objetivo de reduzir a informalidade laboral e a participação de trabalhadores no comércio informal.Este artículo tiene como objetivo analizar el proceso que ha vivido la ciudad de Medellín en la configuración de una economía de comercio informal, a partir de la incidencia que han tenido la desindustrialización y la promulgación de reformas laborales neoliberales. Por medio de una revisión bibliográfica y documental se realiza una contextualización histórica de estos factores, relacionando su impacto con las condiciones del comercio informal. A partir de esta revisión, se evidencia que la apuesta que asumió Medellín de convertirse en una ciudad de servicios, requiere poner especial atención a la generación de empresas y de empleos con altos niveles de innovación y de cualificación, con el fin de reducir la informalidad laboral y la participación de ocupados en el comercio informal

De cómo la Administración podrá desarrollar una teoría que favorezca el bienestar

La administración como campo del conocimiento ha dedicado sus esfuerzos a producir teorías, métodos y técnicas que permiten desarrollar la racionalidad prevista por el sistema económico imperante, con lo cual ha contribuido al establecimiento de desigualdades inicuas y a la destrucción de la naturaleza.Resolver el problema de cómo administrar, ha llevado a encontrar soluciones y modelos que buscan la eficiencia en la relación costo-beneficio para satisfacción de los inversionistas privados, desconociendo sus impactos sociales y ecológicos.Las escuelas y los tratadistas que producen las teorías de la administración debería ocuparse de diseñar modelos organizacionales que incorporen al sistema económico nuevos conceptos y nuevas estructuras de costos que incluyan la cooperación y la ecología al lado del concepto de competencia.Administration, as a field of knowledge, has dedicated its efforts into producing theories. aproaches and techniques that open way to the development of rationality, foreseen by the ruling economical systems, with which it has contributed to the establishment of iniquitous inequalities and to the destruction of nature.Resolving the problem of how to administrate has led into finding solutions that seek effi-ciency in the cost-benefit relatinship for the satisfaction of private investors, failing to rec-ognize its social and ecological impacts.Schools and experts who produce theories of administration should occupy themselves in designing organizational models that would incorpórate new concepts and new structures of costs to the economical system, which in-clude cooperation and ecology along with the concept of competition

Biotecnología Moderna para el Desarrollo de la Agricultura en Colombia

Colombia is currently one of the most promising countries with regard to its potential for agricultural development and for generating food supply for current and future human generations. This is owing to factors such as availability of land, water, topographical diversity, as well as political factors. Nevertheless, Colombia will reach this full potential if it adopts available technologies that can meet the current global challenges faced by the agriculture in the 21st century: among others, world population growth, increase in average life expectancy, high degree of malnutrition, climate change, wrong agricultural practices. Here is presented how modern biotechnology is an important ally as a wide range of technologies and innovative systems can be applied where they are most needed: for increasing cultivation productivity, resisting both biotic and abiotic factors, and ensuring food safety. In this study is showed evidence with regard to significant benefits of adopting biotechnological crops to contribute to food safety and how they are already being implemented in both developed and developing countries. Using modern technology, there are open opportunities for the country in search of circular bio-based economy, strengthen its food sovereignty and to serve as an agricultural breadbasket to Latin America and the World.Colombia es actualmente uno de los países más prometedores en cuanto a su potencial para el desarrollo agrícola y para generar alimentos para las generaciones humanas actuales y futuras. Esto se debe a factores como la disponibilidad de tierra, agua, diversidad topográfica, así como a factores políticos. Sin embargo, Colombia alcanzará su pleno potencial de desarrollo agrícola sostenible si adopta las tecnologías disponibles que puedan hacer frente a los desafíos globales actuales que enfrenta la agricultura en el siglo XXI: entre otros, el crecimiento de la población mundial, el incremento en el promedio de la esperanza de vida, alto grado de desnutrición, cambio climático, uso de practicas agrícolas equivocadas. Aquí es presentado cómo la biotecnología moderna es un aliado importante ya que se puede aplicar una amplia gama de tecnologías y sistemas innovadores donde más se necesitan: aumentar la productividad y sostenibilidad del cultivo, resistir los factores de estrés bióticos y abióticos y garantizar la seguridad alimentaria. En este estudio se muestra evidencia sobre los beneficios significativos de la adopción de cultivos biotecnológicos para contribuir a la inocuidad de los alimentos y como ellos ya se están implementando en los países desarrollados y en vía de desarrollo. Usando tecnologías modernas, hay oportunidades abiertas para el país en la búsqueda de una economía circular de base biológica, que fortalezca su soberanía alimentaria y para servir como despensa agrícola para América Latina y el mundo

Relación entre el principio de reciprocidad y el compromiso del consumidor

The relational perspective of marketing has gained much relevance even in current transition towards an increasingly significant digitization. The objective of this article is to identify the relationship between the principle of reciprocity and consumer engagement behaviors, in order to present the characteristics that a marketing should have in which the reciprocal links between organizations for profit with their clients are privileged. For this, a bibliographic review was carried out, in which 32 articles (published in academic journals) that studied the subject of consumer brands engagement were consulted and 30 that reference studies related to solidarity and altruistic manifestations in human beings, which are linked to the principle of reciprocity. From this review, it can be indicated that brands with human and hedonic characteristics are much more likely to encourage brand engagement behaviors in their customers, despite this it seems extremely ambitious to establish a relationship like the one that arises between humans, for this reason, many companies use incentives to strengthen ties to their buyers. In this sense, it is considered that a strategy based on the principle of reciprocity would be much more sustainable for this purpose, achieving that customers are linked to organizations based on a shared purpose, that contributes to the common good and that is remunerated in terms of engagement behaviors.El enfoque relacional del marketing ha ganado mucha relevancia incluso en medio de una transición hacia una digitalización cada vez más significativa. El objetivo del presente artículo es identificar la relación entre el principio de reciprocidad y comportamientos de compromiso del consumidor, con el fin de plantear las características que debería tener un marketing en que se privilegien los vínculos recíprocos entre organizaciones con fines lucrativos con sus clientes. Para esto, se realizó una revisión bibliográfica de 32 artículos, publicados en revistas académicas, que abordan el tema del compromiso del consumidor con marcas y de 30 que referencian estudios relacionados con manifestaciones solidarias y altruistas en seres humanos, las cuales se vinculan con el principio de reciprocidad. A partir de esta revisión, se puede indicar que las marcas con características humanas y hedónicas son mucho más proclives a incentivar comportamientos de compromiso en sus clientes, a pesar de esto parece extremadamente ambicioso lograr establecer una relación como la que se da entre seres humanos, por lo que muchas empresas usan incentivos para estrechar los vínculos con sus compradores. En este sentido, se considera que una estrategia basada en el principio de reciprocidad sería mucho más sostenible para tal fin, logrando que los clientes se vinculen con las organizaciones a partir de un propósito compartido, que aporte al bien común y que sea retribuido en términos de comportamientos de compromiso

Relaciones e integraciones de la teoría antropológica de lo didáctico y la génesis instrumental

Se presentan algunas reflexiones frente al papel que desempeña la integración de la Teoría Antropológica de lo Didáctico (TAD) y la génesis instrumental en dos experiencias investigativas con el uso de las calculadoras graficadoras algebraicas, CBR (Calculator Based Ranger) y/o Lápiz/Papel (L/P). Inicialmente se espera presentar algunos aspectos de la TAD y la Génesis Instrumental, posteriormente se muestran las necesidades de vinculación de ambas teorías, razones que se ratifican y ejemplifican en dos investigaciones

Nonequilibrium dynamics of a stochastic model of anomalous heat transport: numerical analysis

We study heat transport in a chain of harmonic oscillators with random elastic collisions between nearest-neighbours. The equations of motion of the covariance matrix are numerically solved for free and fixed boundary conditions. In the thermodynamic limit, the shape of the temperature profile and the value of the stationary heat flux depend on the choice of boundary conditions. For free boundary conditions, they also depend on the coupling strength with the heat baths. Moreover, we find a strong violation of local equilibrium at the chain edges that determine two boundary layers of size $\sqrt{N}$ (where $N$ is the chain length), that are characterized by a different scaling behaviour from the bulk. Finally, we investigate the relaxation towards the stationary state, finding two long time scales: the first corresponds to the relaxation of the hydrodynamic modes; the second is a manifestation of the finiteness of the system.Comment: Submitted to Journal of Physics A, Mathematical and Theoretica

Feeding ecology of elasmobranch fishes in coastal waters of the Colombian Eastern Tropical Pacific

<p>Abstract</p> <p>Background</p> <p>Stomach contents of 131 specimens of five elasmobranch species (<it>Mustelus lunulatus</it>, <it>Dasyatis longa</it>, <it>Rhinobatos leucorhynchus</it>, <it>Raja velezi </it>and <it>Zapteryx xyster</it>) caught in the central fishing zone in the Pacific Ocean of Colombia were counted and weighed to describe feeding habits and dietary overlaps.</p> <p>Results</p> <p>Twenty-one prey items belonging to four major groups (stomatopods, decapods, mollusks and fish) were identified. Decapod crustaceans were the most abundant prey found in stomachs. The mantis shrimp <it>Squilla panamensis </it>was the main prey item in the diet of <it>M. lunulatus</it>; tiger shrimp <it>Trachypenaeus </it>sp. was the main prey item in the diet of <it>Rhinobatos leucorhynchus </it>and <it>Raja velezi</it>, and Penaeidae shrimp were the main prey items in the diet of <it>Z. xyster</it>. Furthermore, fish were important in the diet of <it>Raja velezi, Z. xyster </it>and <it>D. longa</it>. The greatest diet breadth corresponded to <it>Z. xyster </it>whereas <it>M. lunulatus </it>was the most specialized predator. Finally, four significant diet overlaps between the five species were found, attributable mainly to Squillidae, Penaeidae and Fish.</p> <p>Conclusion</p> <p>Shrimps (Penaeidae and stomatopods) and benthic fishes were the most important food types in the diet of the elasmobranch species studied. Diet breadth and overlap were relatively low. Determination of food resource partitioning among the batoid species studied was not possible. However, we identified partitions in other niche axes (time of feeding activity and habitat utilization). It is possible to assume that diffuse competition could be exceeding the biunivocal competition among the studied species. Therefore, this assemblage would have a strong tendency to trophic guild formation.</p

Nonequilibrium dynamics of a stochastic model of anomalous heat transport

We study the dynamics of covariances in a chain of harmonic oscillators with conservative noise in contact with two stochastic Langevin heat baths. The noise amounts to random collisions between nearest-neighbour oscillators that exchange their momenta. In a recent paper, [S Lepri et al. J. Phys. A: Math. Theor. 42 (2009) 025001], we have studied the stationary state of this system with fixed boundary conditions, finding analytical exact expressions for the temperature profile and the heat current in the thermodynamic (continuum) limit. In this paper we extend the analysis to the evolution of the covariance matrix and to generic boundary conditions. Our main purpose is to construct a hydrodynamic description of the relaxation to the stationary state, starting from the exact equations governing the evolution of the correlation matrix. We identify and adiabatically eliminate the fast variables, arriving at a continuity equation for the temperature profile T(y,t), complemented by an ordinary equation that accounts for the evolution in the bulk. Altogether, we find that the evolution of T(y,t) is the result of fractional diffusion.Comment: Submitted to Journal of Physics A, Mathematical and Theoretica

Parametric and sensitivity analysis for a proposed filtered tailings storage facility in challenging topography

Parametric and sensitivity analyses were performed for a proposed filtered tail- ings storage facility in challenging topography from the Southern Peru region. The purpose was to identify elements which are likely to dictate performance and stability, and to understand the risk profile for the facility. The analyses were performed varying: foundation material physical and hydraulic properties, tailings physical and hydraulic properties, foundation configuration, seismicity, and staged construction. The physical properties of the foundation material were varied by changing the Mohr-Coulomb strength parameters c’ and φ’, whereas the hydraulic properties were varied by moving the groundwater table upwards or saturating a larger amount of the foundation material. A similar approach was adopted in order to vary the physical and hydraulic properties of the tailings. The foundation configuration was varied by hypothetically moving the starter buttress closer to the edge of steep slopes further downhill from the facility. Staged construction stability analyses were simulated by analyzing filtered tailings fill configurations, which followed the overall design slope but varied in height. All analyses presented herein were conducted for the most critical failure mode for each scenario. The results from these parametric analyses showed that the design of the facility was highly sensitive to tailings potential saturation. In the simulation scenarios, saturation of the tailings caused instability in both static and seismic conditions. This sensitivity to moisture conditions highlighted the importance of properly defining the unsaturated filtered tailings parameters and simulating water infiltration processes through the vadose zone.Fil: Preciado, H. F. AMEC S.A; Perú.Fil: Ale, J. AMEC S.A; Perú.Fil: Byler, B. AMEC Englewood; USA.Fil: Perez, F. AMEC S.A; Perú.Fil: Mejía, V. AMEC S.A; Perú.Fil: McIver, D. Minera IRL SA; Perú.Otras Ingeniería Civi