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Imagen de apoyo de  Una mirada a los patrones demográficos de las misiones jesuitas de Paraguay

Una mirada a los patrones demográficos de las misiones jesuitas de Paraguay

Por: Robert H. Jackson | Fecha: 27/12/2004

Este artículo analiza la historia demográfica de las misiones jesuitas de Paraguay con el fin de ofrecer nuevas perspectivas basadas en un enfoque comparativo. Se plantea que los patrones demográficos en las misiones guaraníes fueron únicos, lo cual se aprecia al ser comparados con las misiones de otras fronteras de la América española, como la del norte de México. Mientras que las poblaciones nativas disminuyeron en estas misiones, las poblaciones guaraníes se recuperaron y crecieron a través de la reproducción natural, aun después de una severa mortalidad causada por las epidemias. Muchos pueblos nativos obligados a vivir en las misiones o en otras fronteras españolas de las Américas enfrentaron una virtual extinción biológica y cultural, mientras que los guaraníes siguieron siendo una población viable después de la expulsión de los jesuitas en 1768 y el traspaso de las antiguas misiones durante las tres primeras décadas del siglo XIX.
Fuente: Icanh - Fronteras de la Historia Tipo de contenido: Artículos
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Una mirada a los patrones demográficos de las misiones jesuitas de Paraguay

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Imagen de apoyo de  Non-gaussianity from the second-order cosmological perturbation

Non-gaussianity from the second-order cosmological perturbation

Por: David H; Rodríguez García Lyth | Fecha: 01/01/2005

Cosmological scales leave the horizon during in?ation and reenter it after big bang nucleosynthesis. Throughout the superhorizon era it is very useful to de?ne a primordial cosmological curvature perturbation, which is conserved if and only if pressure throughout the Universe is a unique function of energy density (the adiabatic pressure condition) [1–7].Observation directly constrains the curvature perturbation at the very end of the superhorizon era, a few Hubble times before cosmological scales start to enter the horizon, when it apparently sets the initial condition for the subsequent evolution of all cosmological perturbations. The observed curvature perturbation is almost Gaussian with an almost scale-invariant spectrum.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Artículos
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Non-gaussianity from the second-order cosmological perturbation

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Imagen de apoyo de  Leptogenesis and tensor polarisation from a gravitational Chern-Simons term

Leptogenesis and tensor polarisation from a gravitational Chern-Simons term

Por: Yeinzon; Lyth Rodríguez García | Fecha: 01/01/2005

Within an effective field theory derived from string theory, the universal axion has to be coupled to the the gravitational Chern-Simons (gCS) term. During any era when the axion field is varying, the vacuum fluctuation of the gravitational wave amplitude will then be circularly polarised, generating an expectation value for the gCS term.The polarisation may be observable through the Cosmic Microwave Background, and the vacuum expectation value of the gCS term may generate the baryon asymmetry of the Universe.We argue here that such effects cannot be computed without further input from string theory, since the `vacuum' in question is unlikely to be the field-theoretic one.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Artículos
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Leptogenesis and tensor polarisation from a gravitational Chern-Simons term

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Imagen de apoyo de  Are the New Physics Contributions from the Left-Right Symmetric Model Important for the Indirect CP Violation in the Neutral B Mesons?

Are the New Physics Contributions from the Left-Right Symmetric Model Important for the Indirect CP Violation in the Neutral B Mesons?

Por: Yeinzon; Quimbay Rodríguez García | Fecha: 01/01/2005

Several works analyzing the new physics contributions from the LeftRight Symmetric Model to the CP violation phenomena in the neutral B mesons can be found in the literature. These works exhibit interesting and experimentally sensible deviations from the Standard Model predictions but at the expense of considering a low right scale ?R around 1 TeV.However, when we stick to the more conservative estimates for ?R which say that it must be at least 107 GeV, no experimentally sensible deviations from the Standard Model appear for indirect CP violation. This estimate for ?R arises when the generation of neutrino masses is considered. In spite of the fact that this scenario is much less interesting and says nothing new about both the CP violation phenomenon and the structure of the LeftRight Symmetric Model, this possibility must be taken into account for the sake of completeness and when considering the see-saw mechanism that provides masses to the neutrino sector.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Artículos
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Are the New Physics Contributions from the Left-Right Symmetric Model Important for the Indirect CP Violation in the Neutral B Mesons?

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Imagen de apoyo de  Low scale inflation and the immediate heavy curvaton decay = Inflacion de baja energia y el decaimiento inmediato del curvaton pesado

Low scale inflation and the immediate heavy curvaton decay = Inflacion de baja energia y el decaimiento inmediato del curvaton pesado

Por: Yeinzon Rodríguez García | Fecha: 01/01/2005

The end of a thermal inflation era, driven by the rolling of a flaton fi eld coupled to the curvaton, cause a huge increase in the curvaton mass and decay rate while the curvaton is still frozen. It is shown that, if this increase is enough for the curvaton to immediately decay, low scale in inflation with Hubble parameter.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Artículos
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Low scale inflation and the immediate heavy curvaton decay = Inflacion de baja energia y el decaimiento inmediato del curvaton pesado

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Imagen de apoyo de  Inflationary prediction for primordial non-gaussianity = La prediccion inflacionaria acerca de la no-gaussianidad primordial

Inflationary prediction for primordial non-gaussianity = La prediccion inflacionaria acerca de la no-gaussianidad primordial

Por: David H; Rodríguez García Lyth | Fecha: 01/01/2005

We extend the Infinite N formalism so that it gives all of the stochastic properties of the primordial curvature perturbation if the initial ?eld perturbations are Gaussian. The calculation requires only the knowledge of some family of unperturbed universes.A formula is given for the normalization fNL of the bispectrum of, which is the main signal of non-Gaussianity. Examples of the use of the formula are given, and its relation to cosmological perturbation theory is explained.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Artículos
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Inflationary prediction for primordial non-gaussianity = La prediccion inflacionaria acerca de la no-gaussianidad primordial

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Imagen de apoyo de  The impact of marketing systems on soil sustainability of agriculture in developing countries: a method and an application

The impact of marketing systems on soil sustainability of agriculture in developing countries: a method and an application

Por: Jairo; Meulenberg Castaño Galves | Fecha: 01/01/2005

This article is concerned with soil-sustainability problems of agriculture in developing countries, in particular with soil erosion. The aim of our study is to develop a comprehensive model that explains the adoption of sustainable agricultural practices with respect to soil conservation. Our approach includes the following special features:(A) The model is comprehensive in that it includes a large number of institutional, personal–social, economic, and physical explanatory variables.(B) Particular attention is paid to the influence of marketing systems on the adoption of sustainable agricultural practices, which to our knowledge has been neglected in past research.(C) The concept of adopting sustainable agricultural practices (ASAP) is differentiated into a limited number of basic components of soil conservation.(D) The model is estimated by Principal Component Regression, which enhances efficient estimation of the impact of many explanatory variables on ASAP. Our model is applied to Cabuyal hillside farming in Colombia. The application demonstrates the usefulness of the proposed model.ASAP is differentiated into three basic components: soil-disturbance control, soil-protection practices, and run-off control. It appears that soil-disturbance control is particularly influenced by farmers’ characteristics, such as education and managerial variables.The second component, soil-protection practices, appears to be strongly influenced not only by farmers’ managerial variables but also by their relationship with their environment, in particular marketing institutions.The third soil-conservation component, run-off control, is influenced by the physical characteristics of the plot and by the available farm labor. Our empirical results demonstrate the usefulness of the proposed model in designing agricultural policies, because it can determine which variables are more likely to influence the adoption of a specific type of soil conservation.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Artículos
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The impact of marketing systems on soil sustainability of agriculture in developing countries: a method and an application

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Imagen de apoyo de  Low scale inflation and the curvaton mechanism = Inflacion de baja energia y el mecanismo del curvaton

Low scale inflation and the curvaton mechanism = Inflacion de baja energia y el mecanismo del curvaton

Por: Yeinzon; Dimopoulos Rodríguez García | Fecha: 01/01/2005

The primordial curvature perturbation may be due to a `curvaton' field, which dominates (or almost dominates) the energy density before it decays. In the simplest version of the curvaton model the scale of inflation has to be quite high corresponding to a Hubble parameter H>10^7 GeV. We here explore two modifications of the curvaton model which can instead allow inflation at a low scale. (i) The curvaton is a Pseudo Nambu-Goldstone Boson (PNGB), with a symmetry-breaking phase transition during inflation. (ii) The curvaton mass increases suddenly at some moment after the end of inflation but before the onset of the curvaton oscillations.Both proposals can work but not in a completely natural way. Also, the lower bound on the scale of inflation depends somewhat on the details of the framework used. Nevertheless, we show that inflation with H as low as 1 TeV or lower is possible to be attained.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Artículos
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Low scale inflation and the curvaton mechanism = Inflacion de baja energia y el mecanismo del curvaton

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Imagen de apoyo de  Relación entre PM2.5 y PM10 en la ciudad de Bogotá

Relación entre PM2.5 y PM10 en la ciudad de Bogotá

Por: Néstor Yezid; Galvis Rojas Roa | Fecha: 01/01/2005

Se realizaron mediciones simultáneas de material particulado menor a 2.5 micras (PM2.5) y menor a 10 micras (PM10), durante periodos de hasta dos meses, en varias estaciones de la red de monitoreo de calidad del aire de la ciudad de Bogotá y se analizaron los resultados con herramientas estadísticas. Los resultados del análisis muestran una correlación positiva y lineal entre los dos parámetros.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Artículos
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Relación entre PM2.5 y PM10 en la ciudad de Bogotá

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Imagen de apoyo de  Sustainability indicators in the educational and research context

Sustainability indicators in the educational and research context

Por: Adriana Carolina; Ferrer Balas Cortés | Fecha: 01/01/2005

As UNESCO indicates ""The Decade of the United Nations for the education with a view to the sustainable development tries to promote the education as foundation of a more viable society for the humanity and to integrate the sustainable development in the system of school education to all the levels”. In essence it proposes to stimulate a solidarity education that contributes to a correct perception of the world state, generate attitudes and responsible behaviors and preparefor the decision making towards the achievement of a cultural plural and physically sustainable development.This way the UPC has developed in its new study plan of studies, a system of generic competitions solved in seven levels: entrepreneur and innovation, sustainability and social understanding, third language, efficient oral and writing communication, team work, solvent use of the resources of information, autonomous learning. With this, as a base of investigation, a group of indicators where developed under the EMAS Project umbrella; that would give the university a system to assess the educational processes that promote the competition in SUSTAINABILITY AND SOCIAL COMMITMENT.Nevertheless, as sustainability is not based on a linear definition, but on the comprehension of the interconnections between the different aspects that it concerns, the indicators needed to give answer from different dimensions. That is to say, it where developed a range of indicators that concerned the different degrees of conscience and knowledge that can be acquired during an educational process.These, took into account on one hand the conceptual knowledge acquired and on the other, the personal values, attitudes, behaviors developed during an educational process and finally the coherence the students had between them at the end of the course. Having the previous in account there where developed 5 different indicators (Sustainability Credits Implication, Sustainability Students Internalizing, Professional Activity, Sustainability Investigation Implication, Sustainability Promotion and Diffusion Activities) which evaluate different scopes of the education for the sustainability from the school.The development of this Project has been framed under the rules of the utility, practicality, extension possibilities and continuity at the university. Also it has taken into account the different methodologies for obtaining the data needed for the indicators. Until now the results are being of satisfaction because of the easy -way of use in the different campus of the university and schools but also by the easy way of interpretation and understanding.
Fuente: Biblioteca Virtual Banco de la República Tipo de contenido: Artículos
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Sustainability indicators in the educational and research context

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