1000 resultados para 338.2728
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El presente trabajo busca analizar los factores que llevaron a que se produjera una importante dinámica migratoria de venezolanos que llegaron a Colombia a invertir o a trabajar en el sector de hidrocarburos. Específicamente se busca encontrar la incidencia de la política de Seguridad Democrática en este fenómeno tomando como periodo de estudio el gobierno de Álvaro Uribe Vélez, es decir, de 2002 a 2010. Se examina la percepción de seguridad en Colombia vista por los venezolanos y por los colombianos y los diferentes factores que contribuyeron al “boom” petrolero en este país. El resultado de las investigaciones de este estudio de caso permite establecer que la Seguridad Democrática si fue un factor incidente en las dinámicas migratorias pero que se articula junto con otros hechos específicos para que se haya dado de la manera que se dio y que en este texto se expone.
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El presente trabajo se enfoca en el análisis de las acciones de Ecopetrol, empresa representativa del mercado de Extracción de Petróleo y Gas natural en Colombia (SP&G), durante el periodo, del 22 de mayo de 2012 al 30 de agosto de 2013. Durante este espacio de tiempo la acción sufrió una serie de variaciones en su precio las cuales se relacionaban a la nueva emisión de acciones que realizo la Compañía. Debido a este cambio en el comportamiento del activo se generaron una serie de interrogantes sobre, (i) la reacción del mercado ante diferentes sucesos ocurridos dentro de las firmas y en su entorno (ii) la capacidad de los modelos financieros de predecir y entender las posibles reacciones observadas de los activos (entendidos como deuda). Durante el desarrollo del presente trabajo se estudiará la pertinencia del mismo, en línea con los objetivos y desarrollos de la Escuela de Administración de la Universidad del Rosario. Puntualmente en temas de Perdurabilidad direccionados a la línea de Gerencia. Donde el entendimiento de la deuda como parte del funcionamiento actual y como variable determinante para el comportamiento futuro de las organizaciones tiene especial importancia. Una vez se clarifica la relación entre el presente trabajo y la Universidad, se desarrollan diferentes conceptos y teorías financieras que han permitido conocer y estudiar de manera más específica el mercado, con el objetivo de reducir los riesgos de las inversiones realizadas. Éste análisis se desarrolla en dos partes: (i) modelos de tiempo discreto y (ii) modelos de tiempo continúo. Una vez se tiene mayor claridad sobre los modelos estudiados hasta el momento se realiza el respectivo análisis de los datos mediante modelos de caos y análisis recurrente los cuales nos permiten entender que las acciones se comportan de manera caótica pero que establecen ciertas relaciones entre los precios actuales y los históricos, desarrollando comportamientos definidos entre los precios, las cantidades, el entorno macroeconómico y la organización. De otra parte, se realiza una descripción del mercado de petróleo en Colombia y se estudia a Ecopetrol como empresa y eje principal del mercado descrito en el país. La compañía Ecopetrol es representativa debido a que es uno de los mayores aportantes fiscales del país, pues sus ingresos se desprenden de bienes que se encuentran en el subsuelo por lo que la renta petrolera incluye impuestos a la producción transformación y consumo (Ecopetrol, 2003). Por último, se presentan los resultados del trabajo, así como el análisis que da lugar para presentar ciertas recomendaciones a partir de lo observado.
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The high Km glucose transporter GLUT2 is a membrane protein expressed in tissues involved in maintaining glucose homeostasis, and in cells where glucose-sensing is necessary. In many experimental models of diabetes, GLUT2 gene expression is decreased in pancreatic beta-cells, which could lead to a loss of glucose-induced insulin secretion. In order to identify factors involved in pancreatic beta-cell specific expression of GLUT2, we have recently cloned the murine GLUT2 promoter and identified cis-elements within the 338-bp of the proximal promoter capable of binding islet-specific trans-acting factors. Furthermore, in transient transfection studies, this 338-bp fragment could efficiently drive the expression of the chloramphenicol acetyl transferase (CAT) gene in cell lines derived from the endocrine pancreas, but displayed no promoter activity in non-pancreatic cells. In this report, we tested the cell-specific expression of a CAT reporter gene driven by a short (338 bp) and a larger (1311 bp) fragment of the GLUT2 promoter in transgenic mice. We generated ten transgenic lines that integrated one of the constructs. CAT mRNA expression in transgenic tissues was assessed using the RNAse protection assay and the quantitative reverse transcribed polymerase chain reaction (RT-PCR). Overall CAT mRNA expression for both constructs was low compared to endogenous GLUT2 mRNA levels but the reporter transcript could be detected in all animals in the pancreatic islets and the liver, and in a few transgenic lines in the kidney and the small intestine. The CAT protein was also present in Langerhans islets and in the liver for both constructs by immunocytochemistry. These findings suggest that the proximal 338 bp of the murine GLUT2 promoter contain cis-elements required for the islet-specific expression of GLUT2.
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The first phase of this research involved an effort to identify the issues relevant to gaining a better understanding of the County Engineering profession. A related objective was to develop strategies to attract responsible, motivated and committed professionals to pursue County Engineering positions. In an era where a large percentage of County Engineers are reaching retirement age, the shrinking employment pool may eventually jeopardize the quality of secondary road systems not only in Iowa, but nationwide. As we move toward the 21st century, in an era of declining resources, it is likely that professional staff members in charge of secondary roads will find themselves working with less flexible budgets for the construction and maintenance of roads and bridges. It was important to understand the challenges presented to them, and the degree to which those challenges will demand greater expertise in prioritizing resource allocations for the rehabilitation and maintenance of the 10 million miles of county roads nationwide. Only after understanding what a county engineer is and what this person does will it become feasible for the profession to begin "selling itself", i.e., attracting a new generation of County Engineers. Reaching this objective involved examining the responsibilities, goals, and, sometimes, the frustrations experienced by those persons in charge of secondary road systems in the nine states that agreed to participate in the study. The second phase of this research involved addressing ways to counter the problems associated with the exodus of County Engineers who are reaching retirement age. Many of the questions asked of participants asked them to compare the advantages and disadvantages of public sector work with the private sector. Based on interviews with nearly 50 County Engineers and feedback from 268 who returned surveys for the research, issues relevant to the profession were analyzed and recommendations were made to the profession as it prepares to attract a new generation. It was concluded that both State and Regional Associations for County Engineers, and the National Association of County Engineers are most well-situated to present opportunities for continued professional development. This factor is appealing for those who are interested in competitive advantages as professionals. While salaries in the public sector may not be able to effectively compete with those offered by the private sector, it was concluded that this is only one factor of concern to those who are in the business of "public service". It was concluded, however, that Boards of Supervisors and their equivalents in other states will need to more clearly understand the value of the contributions made by County Engineers. Then the selling points the profession can hope to capitalize on can focus on the strength of state organizations and a strong national organization that act as clearinghouses of information and advocates for the profession, as well as anchors that provide opportunities for staying current on issues and technologies.
Contribution of Intronic miR-338-3p and Its Hosting Gene AATK to Compensatory β-Cell Mass Expansion.
Resumo:
The elucidation of the mechanisms directing β-cell mass regeneration and maintenance is of interest, because the deficit of β-cell mass contributes to diabetes onset and progression. We previously found that the level of the microRNA (miRNA) miR-338-3p is decreased in pancreatic islets from rodent models displaying insulin resistance and compensatory β-cell mass expansion, including pregnant rats, diet-induced obese mice, and db/db mice. Transfection of rat islet cells with oligonucleotides that specifically block miR-338-3p activity increased the fraction of proliferating β-cells in vitro and promoted survival under proapoptotic conditions without affecting the capacity of β-cells to release insulin in response to glucose. Here, we evaluated the role of miR-338-3p in vivo by injecting mice with an adeno-associated viral vector permitting specific sequestration of this miRNA in β-cells. We found that the adeno-associated viral construct increased the fraction of proliferating β-cells confirming the data obtained in vitro. miR-338-3p is generated from an intron of the gene coding for apoptosis-associated tyrosine kinase (AATK). Similarly to miR-338-3p, we found that AATK is down-regulated in rat and human islets and INS832/13 β-cells in the presence of the cAMP-raising agents exendin-4, estradiol, and a G-protein-coupled Receptor 30 agonist. Moreover, AATK expression is reduced in islets of insulin resistant animal models and selective silencing of AATK in INS832/13 cells by RNA interference promoted β-cell proliferation. The results point to a coordinated reduction of miR-338-3p and AATK under insulin resistance conditions and provide evidence for a cooperative action of the miRNA and its hosting gene in compensatory β-cell mass expansion.
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Dark greyish-brown sediment with clasts ranging from small to large in size. Clasts are sub-angular to sub-rounded in shape. Fine grained domains can be seen scattered throughout the sample. The sample also contains comet structures, lineations, and minor amounts of rotation structures within the coarser domain.
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Pour toute demande de reproduction de contenu se trouvant dans cette publication, communiquer avec l’Association des diplômés de l’UdeM.
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Incluye cuatro tipos de índices que facilitan la búsqueda de los artículos incluidos en los números 336 a 338 y en el número extraordinario del año 2005. Estos índices agrupan los artículos por las notaciones de la Clasificación Decimal Universal (CDU) y por orden alfabético de autores, títulos y descriptores o materias.