Ecosystem approach to aquaculture and fisheries

Documento que proporciona información del V Seminario Avanzado de Pesca y Acuicultura celebrado en Ifapa de Huelva y organizado por la Agencia Europea de Cooperacion Internacional (AECI) el 12 de noviembre de 2008. <br

Current Algebra in the Path Integral framework

In this letter we describe an approach to the current algebra based in the Path Integral formalism. We use this method for abelian and non-abelian quantum field theories in 1+1 and 2+1 dimensions and the correct expressions are obtained. Our results show the independence of the regularization of the current algebras.Comment: 8 pages, Revtex. One reference added. To appear in Mod. Phys. Lett. A, Vol. 13, No. 27 (1998

Los musgos pleurocárpicos del Valle de México, México

A pesar de su pequeña extensión (7500 km²), el Valle de México es una región de alta diversidad vegetal. Su flora incluye alrededor de 105 especies y variedades de musgos pleurocárpicos, o sea, el 31% del total reconocido para la República Mexicana. El orden Leucodontales incluye 22 taxa, las Hookeriales apenas están representadas por dos especies y las Hypnales por unas 81. Las Leucodontales se encuentran principalmente como epífitas por lo que son comparativamente escasas en el Valle de México; las Hookeriales generalmente crecen en bosques de elevaciones bajas, muy sombreados y húmedos. Las Hypnales, por su parte, representan un orden grande y diverso que se distribuye principalmente en el Hemisferio Norte y, en las zonas tropicales, en elevaciones altas, en los bosques abiertos que abundan en la zona de estudio. Drepanocladus capillifolius e Hygroamblystegium fluviatile se registran por primera vez para México.Despite its small area (7500 km2), the Valle de México is the site of high plant diversity. Its flora includes about 105 species and varieties of pleuocarpous mosses, i.e., 31% of the total recognized for Mexico. The Leucodontales include 22 taxa, the Hookeriales are represented by two species only, and the Hypnales by some 81 taxa. Because of their epiphytic habitat, the Leucodontales are comparatively scarce in the Valle de México; the Hookeriales usually grow in lowland, shaded moist tropical forests. The large and diverse Order Hypnales is a north temperate taxon which, in the tropical latitudes, is distributed at high elevations in open forests that are frequent in the area of study. Drepanocladus capillifolius and Hygroamblystegium fluviatile are recorded for the first time for Mexico

Situación de la enseñanza de la briología en México

The teaching of bryology in Mexico confronts various difficulties that prevent students from having at least a broad overview of what bryophytes are. There are three main problems: lack of institutional facilities, lack of specialized literature and ignorance of the structure, biology and significance of these plants on the part of teachers. To resolve these difficulties, schools must obtain the minimum necessary facilities (Microscopes, laboratory materials ans specialized literature) and request specialists to teach courses and colaborate in workshops and fieldtrips to give teachers a better understanding of bryophytes.La enseñanza de la briología en México enfrenta varios problemas que impiden a los estudiantes obtener siquiera un panorama general de lo que son las briofitas; se han identificado tres problemas principales: la falta de infraestructura institucional, la carencia de bibliografía especializada y el desconocimiento de la estructura, biología e importancia de estas plantas por parte de los profesores. Para superar los problemas es necesario adquirir el equipo minímo indispensable (microscopios, material de laboratorio y literatura especializada) y pedir a los especialistas su participación en cursos, talleres y excursiones para ayudar a los profesores a comprender mejor a este grupo de plantas

Disaster Risk Management by Communities and Local Governments

This study refers to disaster risk management at the local level. The topic was selected by the members of the Natural Disasters Network of the Regional Policy Dialogue, and was presented during its 3rd Meeting, on March 6 and 7, 2003. The goal of this document is to achieve a better knowledge of the best practices and benefits that disaster risk management represents for Latin America and the Caribbean. Included are comparative case studies of the Philippines, Colombia, Guatemala and Switzerland. Also discussed are strengths and weaknesses of local organizations in decentralized systems and financial services for disaster risk management.Disasters, Financial Risk, Decentralization, Civil Society, Environment, disaster risk management

The Development of Colombian Bond Market.

Abstract: In this paper we explore the determinants and the consequences of the development of the corporate bond market in Colombia. We use a large firm-level dataset for the period 1997-2004 and find that the larger, more profitable and more leveraged firms have a higher probability to issue bonds. The econometric results also show that the larger the treasury bond market, the lower the probability that a firm will issue bonds, suggesting the presenceof a crowding out effect. On the demand side, the panel estimations indicate that investors with larger portfolios tend to hold more corporate bonds. Also, from the viewpoint of investors, average bond issue size is a critical variable. Finally, we find that sectors that have more corporate bonds (as percentage of total liabilities) have greater loan quality, and this result is stronger during periods of banking crises. We conclude that bond market development can play an important countercyclical role during periods of financial stress.Resumen: En este trabajo exploramos los determinantes y las consecuencias del desarrollo del mercado de bonos corporativos en Colombia. Utilizamos una muestra amplia con información por firma para el período 1997-2004 y encontramos que las firmas más grandes, rentables y apalancadas tienen una mayor probabilidad de emitir bonos. Los resultados econométricos también muestran que un mayor tamaño del mercado de deuda pública tiene un efecto negativo sobre la probabilidad de las firmas de emitir bonos, lo cual sugiere un efecto de crowding out. Por el lado de la demanda, las estimaciones de panel indican que los inversionistas con portafolios grandes tienen mayor probabilidad de adquirir bonos. Así mismo, desde el punto de vista de los inversionistas, el tamaño promedio de la emisión es una variable crítica. Finalmente, encontramos que los sectores económicos en donde la participación de los bonos dentro del total de pasivos es mayor, tienen una mejor calidad de la cartera y enfrentan con mayor fortaleza los períodos de crisis. Concluimos que el mercado de bonos puede tener un importante papel contra cíclico en períodos de stress financiero.Mercado de bonos, mercado financiero; Bonos corporativos, Inversionistas, Colombia

On the Orbital Period of the Intermediate Polar 1WGA J1958.2+3232

Recently, Norton et al. 2002, on the basis of multiwavelength photometry of 1WGA J1958.2+3232, argued that the -1 day alias of the strongest peak in the power spectrum is the true orbital period of the system, casting doubts on the period estimated by Zharikov et al. 2001. We re-analyzed this system using our photometric and spectroscopic data along with the data kindly provided by Andy Norton and confirm our previous finding. After refining our analysis we find that the true orbital period of this binary system is 4.35h.Comment: 4 pages, 5 figures, Accepted for publication in A&A Letter

A study of local approximation for polarization potentials

We discuss the derivation of an equivalent \textit{l}-independent polarization potential for use in the optical Schr\"{o}dinger equation that describes the elastic scattering of heavy ions. Three diffferent methods are used for this purpose. Application of our theory to the low energy scattering of the halo nucleus $^{11}$Li from a $^{12}$C target is made. It is found that the notion of \textit{l}-independent polarization potential has some validity but can not be a good substitute for the \textit{l}-dependent local equivalent Feshbach polarization potential.Comment: 8 pages, 4 figure