Sentando las bases políticas para la integración económica: el Grupo de Río y la concertación regional

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Privatización portuaria: bases, alternativas y consecuencias

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Política fiscal y medio ambiente: bases para una agenda común

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Complejidad campesina en ecosistemas andinos de altura: bases para políticas de desarrollo

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Manual de contratación pública electrónica para América Latina: bases conceptuales, modelo legal, indicadores, parámetros de interoperabilidad

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Bases para el diseño de un plan estratégico de la Unidad del Sistema de Parques Nacionales y del Sistema Nacional de Áreas Protegidas

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Physiological bases for understanding estrous cycle differences between bos taurus and bos indicus

Background: Although there is some information in the literature discussing differences of the estrous cycle of Bos taurus and Bos indicus cattle, most of the data derive from studies performed in temperate climate countries, under environmental and nutritional conditions very different than those found in tropical countries. Moreover, the physiological basis for understanding the differences between Bos taurus and Bos indicus estrous cycles are still unknown. This review explores the physiological and metabolic bases for understanding the key differences between the Bos taurus and Bos indicus estrous cycle. Moreover, it presents recent results of studies that have directly compared reproductive variables between Zebu and European cattle. Review: The knowledge of reproductive physiology, especially the differences between Bos taurus and Bos indicus, is important for the development and application of different techniques of reproductive management in cattle. In this regard, overall, Bos indicus have a greater number of small ovarian follicles and ovulatory follicles are smaller as compared to Bos taurus. Consequently, Zebu cattle also have smaller corpus luteum (CL). Nevertheless, circulating concentrations of steroid and metabolic hormones are not necessarily higher in European cattle. In fact, some studies have shown that despite ovulating smaller follicles and having smaller CL, Bos indicus cows or heifers have higher circulating concentrations of estradiol, progesterone, insulin and IGF-I compared to Bos taurus females. In addition, there are also substantial differences between Bos indicus and Bos taurus cattle in relation to follicle size at the time of selection of the dominant follicle. Conclusion: Data from very recent studies performed in Brazil have corroborated results from previous reports that have observed substantial differences in the estrous cycle variables of Bos indicus versus Bos taurus cattle. Those differences are probably related to distinct metabolism and metabolic hormone concentrations between Zebu and European cattle. This increased knowledge will allow for the establishment of more adequate reproductive management protocols in both breeds of cattle.

UMP kinase from Mycobacterium tuberculosis: Mode of action and allosteric interactions, and their likely role in pyrimidine metabolism regulation

The pyrH-encoded uridine 5′-monophosphate kinase (UMPK) is involved in both de novo and salvage synthesis of DNA and RNA precursors. Here we describe Mycobacterium tuberculosis UMPK (MtUMPK) cloning and expression in Escherichia coli. N-terminal amino acid sequencing and electrospray ionization mass spectrometry analyses confirmed the identity of homogeneous MtUMPK. MtUMPK catalyzed the phosphorylation of UMP to UDP, using ATP-Mg 2+ as phosphate donor. Size exclusion chromatography showed that the protein is a homotetramer. Kinetic studies revealed that MtUMPK exhibits cooperative kinetics towards ATP and undergoes allosteric regulation. GTP and UTP are, respectively, positive and negative effectors, maintaining the balance of purine versus pyrimidine synthesis. Initial velocity studies and substrate(s) binding measured by isothermal titration calorimetry suggested that catalysis proceeds by a sequential ordered mechanism, in which ATP binds first followed by UMP binding, and release of products is random. As MtUMPK does not resemble its eukaryotic counterparts, specific inhibitors could be designed to be tested as antitubercular agents. © 2010 Elsevier Inc. All rights reserved.

Manual de prospectiva y decisión estratégica: bases teóricas e instrumentos para América Latina y el Caribe

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Bases conceptuales para el ciclo de cursos sobre gerencia de proyectos y programas

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Sentando las bases políticas para la integración económica: el Grupo de Río y la concertación regional

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Bases conceptuales para la elaboración de una nueva agenda sobre los recursos naturales

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ILPES: bases del programa de trabajo para 1987

Presenta las bases del programa de trabajo del ILPES para 1987 en su gestión institucional, dirección de programas de asesoría, capacitación e investigación

ILPES: nuevas bases de trabajo y síntesis de actividades 1986-1987

Presenta los principales lineamientos para el trabajo que el ILPES deberá desempeñar en el próximo bienio, así como un resumen de las actividades realizadas en 1986-1987

Manual de generación de bases de datos REDATAM = REDATAM: database generation manual

Tiene por objetivo principal instruir al usuario, a través de ejemplos, en la creación de nuevas bases de datos.