1000 resultados para Centro Regional de Investigaciones Científicas y Tecnológicas.
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Helcystogramma sp., es una nueva especie de microlepidóptero que afecta desde la siembra hasta la cosecha del boniato o camote (Ipomoea batatas L. Lam.) en Cuba. Debido a la falta de conocimientos y a la escasa bibliografía relacionada con las especies del género Helcystogramma en nuestro país, nos propusimos como objetivo conocer aspectos bio-ecológicos de este microlepidóptero, con la finalidad de proporcionar nuevos conocimientos para un futuro manejo de esta plaga. El trabajo se realizó desde septiembre 2013 a septiembre de 2014, en el Instituto de Investigaciones de Viandas Tropicales (INIVIT), Santo Domingo, Villa Clara, Cuba. Los insectos se estudiaron por observación directa en campos de I. batatas. La larva de este microlepidóptero es muy ágil, dobla la hoja, la cual pega con hilos de seda, creando una protección para su desarrollo hasta el estado de pupa, se alimenta dentro de esta cavidad a partir de la misma hoja, sin afectar la epidermis inferior. Sus poblaciones han aumentado considerablemente, llegando a 20 larvas/m2 en verano. La especies Helcystogramma sp., se cita por primera vez para Cuba y además se registra como una nueva especie de insecto que se alimenta del boniato. ABSTRACT. Primer registro de Helcystogramma sp. (Lepidoptera: Gelechiidae) en Cuba. Helcystogramma sp. is a new species of microlepidoptera affecting from planting to sweet potato (I. batatas L. Lam.) harvest crop in Cuba. Due to the lack of knowledgze and limited literature relate with the Helcystogramma genus in our country, the goal of this study was to know the bioecological aspects of such microlepidoptera, in order to provide new insights for future management of this pest. The study was conducted from September 2013 to September 2014 at the Research Institute of Tropical Root and Tuber Crops, Bananas and Plantains (INIVIT), Santo Domingo, Villa Clara, Cuba. Insects were studied by direct observation in sweet potato (I. batatas) fields. The microlepidoptera larvae is very agile, folds the sheet which sticks with silk threads, creating a protection for its development to the pupal stage. The larvae will feed in the cavity from the same leaf without affecting the lower epidermis. Their populations have increased significantly, reaching 20 larvae / m2 in summer. The species Helcystogramma sp., is cited for the first time in Cuba and it is reported as a new species of insect that feeds on sweet potato leaves.
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Central America is one of the most vulnerable regions to the adverse effects of climate change, due to the rise of frequency and intensity that hydrometeorological phenomena have occurred in recent years. In El Salvador 484 people died and 800,000 more were affected because these extreme events and economic losses reached up to 6.711 million dollars. According to the climate projections over the next 50 years in the territory, is expected that extreme events such as droughts and rainfall will intensify. Within the last 30 years, July of 2014 is considered the one with less rainfall. Meanwhile, Tropical Depression 12E in 2011 provoked an outstanding rainfall average of 1,137 mm, affecting more than 500,000 people; most of them live in the coastal zone. The death of 34 people and living economic losses of 840.4 million was recorded, equivalent to 4% of GDP. El Salvador has policies, national plans and strategies aimed to reducing vulnerability, promoting adaptation to these changes and more effective risk management. This paper compiles the impacts of climate variability in El Salvador and the efforts of the State on adaptation to improve environmental and social resilience.
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El sector micro empresarial en El Salvador afronta numerosos problemas que impiden el aumento de la competitividad y desarrollo de este. Para solventar la situación a la que se están enfrentando las Microempresas, surge el Centro de Desarrollo de Micro y Pequeñas Empresas (CDMYPE) que busca dar apoyo a través de capacitaciones y asesorías a los microempresarios; pero el no tener identificadas a las Microempresas específicamente a las que están domiciliadas en el departamento de Cuscatlán impide la construcción de un perfil para este sector y que el CDMYPE-ILOBASCO institución que atiende a este departamento, pueda ofrecer sus servicios a los microempresarios. De ahí la necesidad de realizar la investigación titulada “Identificación y construcción del perfil de las Microempresas del departamento de Cuscatlán potenciales usuarios de Centro de Desarrollo de Micro y Pequeñas Empresas sede Ilobasco (CDMYPE-ILOBASCO) en el año 2015”; con la aplicación del método científico y la metodología aplicada que permitió conocer las características de las Microempresas del departamento de Cuscatlán, mediante la recopilación de la información; y proceder así al análisis de los resultados para la construcción del perfil de los potenciales usuarios del CDMYPE-ILOBASCO. Los resultados de la investigación y la construcción del perfil permitirán aumentar el número de Microempresas atendidas por el CDMYPE-ILOBASCO; y con el apoyo recibido por esta institución las Microempresas puedan mejorar y fortalecer sus áreas estratégicas, su forma de reacción ante el entorno y aumentar así sus ventas y nivel de empleo, generando impacto económico para el departamento. ABSTRACT The micro enterprise sector in El Salvador faces many problems that prevent increasing the competitiveness and development of this. To overcome the situation they are facing Microenterprise arises Development Center of Micro and Small Enterprises (CDMYPE) which seeks to support through training and advisory services to microentrepreneurs; but not having identified Microenterprise specifically those that are domiciled in the department of Cuscatlán prevents the construction of a profile for this sector and the CDMYPE-ILOBASCO institution that attends this department, can offer their services to microentrepreneurs. Hence the need from research entitled "Identification and construction of the profile of Microenterprises from department Cuscatlán potential users Development Center Micro and Small Enterprises headquarters Ilobasco (CDMYPE-ILOBASCO) in the year 2015"; with the application of scientific method and the methodology applied that allowed to know the characteristics of the Microenterprise of department Cuscatlán, by collecting information; and thus proceed to the analysis of the results, to build the profile of potential users of CDMYPE-ILOBASCO. The results of research and profile construction of will allow increase the number of Microenterprises served by the CDMYPE-ILOBASCO; and with the support received by this institution the Microenterprises can improve and strengthen its strategic areas, their way of reaction before the environment and increase their sales and employment levels, generating economic impact for the department.
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Conspectus: The challenges of the 21st century demand scientific and technological achievements that must be developed under sustainable and environmentally benign practices. In this vein, click chemistry and green chemistry walk hand in hand on a pathway of rigorous principles that help to safeguard the health of our planet against negligent and uncontrolled production. Copper-catalyzed azide–alkyne cycloaddition (CuAAC), the paradigm of a click reaction, is one of the most reliable and widespread synthetic transformations in organic chemistry, with multidisciplinary applications. Nanocatalysis is a green chemistry tool that can increase the inherent effectiveness of CuAAC because of the enhanced catalytic activity of nanostructured metals and their plausible reutilization capability as heterogeneous catalysts. This Account describes our contribution to click chemistry using unsupported and supported copper nanoparticles (CuNPs) as catalysts prepared by chemical reduction. Cu(0)NPs (3.0 ± 1.5 nm) in tetrahydrofuran were found to catalyze the reaction of terminal alkynes and organic azides in the presence of triethylamine at rates comparable to those achieved under microwave heating (10–30 min in most cases). Unfortunately, the CuNPs underwent dissolution under the reaction conditions and consequently could not be recovered. Compelling experimental evidence on the in situ generation of highly reactive copper(I) chloride and the participation of copper(I) acetylides was provided. The supported CuNPs were found to be more robust and efficient catalyst than the unsupported counterpart in the following terms: (a) the multicomponent variant of CuAAC could be applied; (b) the metal loading could be substantially decreased; (c) reactions could be conducted in neat water; and (d) the catalyst could be recovered easily and reutilized. In particular, the catalyst composed of oxidized CuNPs (Cu2O/CuO, 6.0 ± 2.0 nm) supported on carbon (CuNPs/C) was shown to be highly versatile and very effective in the multicomponent and regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles in water from organic halides as azido precursors; magnetically recoverable CuNPs (3.0 ± 0.8 nm) supported on MagSilica could be alternatively used for the same purpose under similar conditions. Incorporation of an aromatic substituent at the 1-position of the triazole could be accomplished using the same CuNPs/C catalytic system starting from aryldiazonium salts or anilines as azido precursors. CuNPs/C in water also catalyzed the regioselective double-click synthesis of β-hydroxy-1,2,3-triazoles from epoxides. Furthermore, alkenes could be also used as azido precursors through a one-pot CuNPs/C-catalyzed azidosulfenylation–CuAAC sequential protocol, providing β-methylsulfanyl-1,2,3-triazoles in a stereo- and regioselective manner. In all types of reaction studied, CuNPs/C exhibited better behavior than some commercial copper catalysts with regard to the metal loading, reaction time, yield, and recyclability. Therefore, the results of this study also highlight the utility of nanosized copper in click chemistry compared with bulk copper sources.
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16 hojas.
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Introducción En 1973 se fundó la Universidad Nacional con sede en Heredia, se creo una de sus unidades académicas a al Escuela de Historia, la cual he venido funcionando interrumpidamente desde entonces. A lo largo de estos dieciséis años, la meta de esta Escuela ha sido la de brindar un especial impulso a la investigación atendiendo a necesidades temáticas y metodológicas que aporten una nueva interpretación a la historia costarricense cuestionando mitos por largo tiempos aceptados e incursionando en campos hasta entonces escasa o totalmente inexplorados.
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Caracterización general del país, con una descripción y análisis crítico del proceso de planificación y la regionalización de Panamá, se exploran las tendencias de la diferenciación regional a partir de propuestas concretas sobre los alcances de la planificación regional.
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Background: The cattle tick, Rhipicephalus (Boophilus) microplus, economically impact cattle industry in tropical and subtropical regions of the world. The morphological and genetic differences among R. microplus strains have been documented in the literature, suggesting that biogeographical and ecological separation may have resulted in boophilid ticks from America/Africa and those from Australia being different species. To test the hypothesis of the presence of different boophilid species, herein we performed a series of experiments to characterize the reproductive performance of crosses between R. microplus from Australia, Africa and America and the genetic diversity of strains from Australia, Asia, Africa and America. Results: The results showed that the crosses between Australian and Argentinean or Mozambican strains of boophilid ticks are infertile while crosses between Argentinean and Mozambican strains are fertile. These results showed that tick strains from Africa (Mozambique) and America (Argentina) are the same species, while ticks from Australia may actually represent a separate species. The genetic analysis of mitochondrial 12S and 16S rDNA and microsatellite loci were not conclusive when taken separately, but provided evidence that Australian tick strains were genetically different from Asian, African and American strains. Conclusion: The results reported herein support the hypothesis that at least two different species share the name R. microplus. These species could be redefined as R. microplus (Canestrini, 1887) (for American and African strains) and probably the old R. australis Fuller, 1899 (for Australian strains), which needs to be redescribed. However, experiments with a larger number of tick strains from different geographic locations are needed to corroborate these results.
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Aims. We create a catalogue of simulated fossil groups and study their properties, in particular the merging histories of their first-ranked galaxies. We compare the simulated fossil group properties with those of both simulated non-fossil and observed fossil groups. Methods. Using simulations and a mock galaxy catalogue, we searched for massive (>5 x 10(13) h(-1) M-circle dot) fossil groups in the Millennium Simulation Galaxy Catalogue. In addition, we attempted to identify observed fossil groups in the Sloan Digital Sky Survey Data Release 6 using identical selection criteria. Results. Our predictions on the basis of the simulation data are: (a) fossil groups comprise about 5.5% of the total population of groups/clusters with masses larger than 5 x 10(13) h(-1) M-circle dot. This fraction is consistent with the fraction of fossil groups identified in the SDSS, after all observational biases have been taken into account; (b) about 88% of the dominant central objects in fossil groups are elliptical galaxies that have a median R-band absolute magnitude of similar to-23.5-5 log h, which is typical of the observed fossil groups known in the literature; (c) first-ranked galaxies of systems with M > 5 x 10(13) h(-1) M-circle dot, regardless of whether they are either fossil or non-fossil, are mainly formed by gas-poor mergers; (d) although fossil groups, in general, assembled most of their virial masses at higher redshifts in comparison with non-fossil groups, first-ranked galaxies in fossil groups merged later, i.e. at lower redshifts, compared with their non-fossil-group counterparts. Conclusions. We therefore expect to observe a number of luminous galaxies in the centres of fossil groups that show signs of a recent major merger.
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Projecte de recerca elaborat a partir d’una estada al Centro Austral de Investigaciones Científicas en Ushuaia (Tierra de Fuego), Argentina, entre juliol i novembre del 2007. Aquesta, s’emmarca dins d’una sèrie de projectes que es van iniciar fa 20 anys entre un equip format per investigadors i investigadores de la UAB, del CSIC, del CADIC i la AIA de Buenos Aires. Aquest treball conjunt encara continua realitzant-se. El projecte inicial va contemplar la intervenció arqueològica a diferents jaciments de la societat Yamana, que habitava a les costes del Canal Beagle. Actualment segueixen les intervencions en jaciments de la costa i també a l’interior de la Isla Grande de Tierra del Fuego. L’estada realitzada forma part d’aquest projecte donat que l’estudi dels mol•luscos obtinguts en aquestes intervencions encara està inèdit. Les restes malacològiques provenen de jaciments de dues zones de Tierra del Fuego: jaciments de l’interior de l’illa amb presència de mol•luscos (Ewan I i Ewan II) i de la costa del Canal Beagle (Lanashuaia i Túnel VII). Els dos primers s’atribueixen a la societat Selknam i els segons a la societat Yamana. L’estada que s’ha realitzat al CADIC ha servit per obtenir informació bibliogràfica sobre les espècies malacològiques que es troben actualment al Canal Beagle, el tipus de costa que aquestes habiten i les condicions ecològiques que cadascuna necessita. També s’ha obtingut informació sobre la zona d’estudi i específicament sobre els estudis de malacofauna realitzats a la zona. Per una altra banda, l’estada al CADIC també ha servit per resoldre dubtes d’identificació d’espècies i sobre les diferències en els ritmes de creixement i de formació de la conquilla de les espècies de pegellides de la zona.
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Leptin, a 16-kDa protein mainly produced by adipose tissue, has been involved in the control of energy balance through its hypothalamic receptor. However, pleiotropic effects of leptin have been identified in reproduction and pregnancy, particularly in placenta, where it was found to be expressed. In the current study, we examined the effect of cAMP in the regulation of leptin expression in trophoblastic cells. We found that dibutyryl cAMP [(Bu)(2)cAMP], a cAMP analog, showed an inducing effect on endogenous leptin expression in BeWo and JEG-3 cell lines when analyzed by Western blot analysis and quantitative RT-PCR. Maximal effect was achieved at 100 microM. Leptin promoter activity was also stimulated, evaluated by transient transfection with a reporter plasmid construction. Similar results were obtained with human term placental explants, thus indicating physiological relevance. Because cAMP usually exerts its actions through activation of protein kinase A (PKA) signaling, this pathway was analyzed. We found that cAMP response element-binding protein (CREB) phosphorylation was significantly increased with (Bu)(2)cAMP treatment. Furthermore, cotransfection with the catalytic subunit of PKA and/or the transcription factor CREB caused a significant stimulation on leptin promoter activity. On the other hand, the cotransfection with a dominant negative mutant of the regulatory subunit of PKA inhibited leptin promoter activity. We determined that cAMP effect could be blocked by pharmacologic inhibition of PKA or adenylyl ciclase in BeWo cells and in human placental explants. Thereafter, we decided to investigate the involvement of the MAPK/ERK signaling pathway in the cAMP effect on leptin induction. We found that 50 microm PD98059, a MAPK kinase inhibitor, partially blocked leptin induction by cAMP, measured both by Western blot analysis and reporter transient transfection assay. Moreover, ERK 1/2 phosphorylation was significantly increased with (Bu)(2)cAMP treatment, and this effect was dose dependent. Finally, we observed that 50 microm PD98059 inhibited cAMP-dependent phosphorylation of CREB in placental explants. In summary, we provide some evidence suggesting that cAMP induces leptin expression in placental cells and that this effect seems to be mediated by a cross talk between PKA and MAPK signaling pathways.
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Pleiotropic effects of leptin have been identified in reproduction and pregnancy, particularly in the placenta, where it works as an autocrine hormone. In this work, we demonstrated that human chorionic gonadotropin (hCG) added to JEG-3 cell line or to placental explants induces endogenous leptin expression. We also found that hCG increased cAMP intracellular levels in BeWo cells in a dose-dependent manner, stimulated cAMP response element (CRE) activity and the cotransfection with an expression plasmid of a dominant negative mutant of CREB caused a significant inhibition of hCG stimulation of leptin promoter activity. These results demonstrate that hCG indeed activates cAMP/PKA pathway, and that this pathway is involved in leptin expression. Nevertheless, we found leptin induction by hCG is dependent on cAMP levels. Treatment with (Bu)(2)cAMP in combination with low and non stimulatory hCG concentrations led to an increase in leptin expression, whereas stimulatory concentrations showed the opposite effect. We found that specific PKA inhibition by H89 caused a significant increase of hCG leptin induction, suggesting that probably high cAMP levels might inhibit hCG effect. It was found that hCG enhancement of leptin mRNA expression involved the MAPK pathway. In this work, we demonstrated that hCG leptin induction through the MAPK signaling pathway is inhibited by PKA. We observed that ERK1/2 phosphorylation increased when hCG treatment was combined with H89. In view of these results, the involvement of the alternative cAMP/Epac signaling pathway was studied. We observed that a cAMP analogue that specifically activates Epac (CPT-OMe) stimulated leptin expression by hCG. In addition, the overexpression of Epac and Rap1 proteins increased leptin promoter activity and enhanced hCG. In conclusion, we provide evidence suggesting that hCG induction of leptin gene expression in placenta is mediated not only by activation of the MAPK signaling pathway but also by the alternative cAMP/Epac signaling pathway.
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Esta gu??a tiene como objetivo poner al alcance de los jovenes, informaci??n acerca de la estructura del sistema educativo en todos sus niveles, as?? como consideraciones generales que mejoran los procesos de toma de decisi??n y madurez vocacional para facilitar la elecci??n de estudios o profesiones que mejor se adapten a las preferencias, aptitudes e intereses de cada uno. Toca los siguientes aspectos : finalidad, caracter??sticas, estructura, condiciones de acceso de todas las ofertas educativas. Tras una explicaci??n del sistema educativo,hace un repaso por los distintos niveles desde educaci??n infantil, desarrolando con mayor amplitud el abanico en secundaria: ESO, Bachillerato, FP reglada,ocupacional u otras modalidades de Formaci??n Continua, as?? como los Programas de Garantia Social, Escuelas Taller, Modalidad de Autoempleo.As?? mismo hace referencia a la Educaci??n Especial, a las Ense??anzas Art??sticas, Ense??anza de Idiomas, Educaci??n de personas adultas, Universidad, Programas Educativos Comunitarios(SOCRATES,LEONARDO),Programas de Nuevas Tecnolog??as de la Informaci??n y de la Comunicaci??n. Por ??ltimo un apartado se dedica a las becas y ayudas al estudio y otro a las direcciones de interes para ampliar la informaci??n.
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Después que muchos Estados se enriquecieran tanto intelectual como económicamente de la explotación o apropiación ilegal de la biodiversidad andina de la cual los miembros de la CAN eran país de origen, surge la necesidad de proteger la riqueza de la región, razón por la cual nace la Decisión 391 en 1996 sobre un Régimen Común de Acceso a Recursos genéticos. De esta manera los países miembros de la CAN se convirtieron en los primeros con un mecanismo de control para el acceso a los recursos genéticos y partición equitativa de los beneficios; buscando con ello sentar bases para la creación de conocimientos sobre el tema, el desarrollo de capacidades científicas y tecnológicas, y la promoción del uso sostenible de los recursos. Sin embargo por razones de carácter nacional la implementación del mismo no ha progresado, generando que los casos de biopiratería aumenten e incluso sean difíciles de prevenir. Siendo este un tema de gran relevancia para Bolivia, Colombia, Ecuador, Perú y Venezuela, esta monografía examinará en las siguientes páginas la reglamentación nacional para comprender a mayor profundidad los defectos y/o cualidades de las decisiones tomadas por los Estados para la aplicación de la Decisión 391, y así mismo evidenciará las razones por las cuales la implementación de la Decisión no ha tenido éxito total sobre el control de la biopiratería, entre ellas la falta de reglamentación, la especificación de roles, la concientización ciudadana e incluso información al público en general.