131 research outputs found

    Efecto del NaCl sobre los parámetros de crecimiento, rendimiento y calidad de la cebolla de bulbo (Allium cepa L.) bajo condiciones controladas

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    El experimento se realizó en el primer semestre de 2010 en los invernaderos de la Facultad de Agronomía, Universidad Nacional de Colombia, Bogotá, con temperatura y humedad relativa promedio de 21°C y 60%, respectivamente. Se evaluó el efecto de concentraciones crecientes en el agua de riego de 0, 30, 60 y 90 mM de NaCl (conductividad eléctrica de 0, 3, 6 y 9 ±0,2 dS m-1, respectivamente) sobre parámetros de crecimiento, rendimiento y calidad en cebolla de bulbo, var. Yellow Granex, en un diseño completamente aleatorizado con cuatro repeticiones. Los niveles salinos crecientes generaron un desarrollo precoz, expresado en acumulación rápida de materia seca (MS) en los primeros estados de crecimiento, teniendo implicaciones fisiológicas en el desarrollo del bulbo. Se presentaron diferencias significativas a partir de la etapa de desarrollo del bulbo para las variables altura, número de hojas y diámetro del pseudotallo de la planta. Asimismo, se registraron reducciones respecto al tratamiento control de 31%, 53% y 70% de MS total, 44%, 53% y 71% de MS de la parte aérea, 28%, 49% y 74% de MS del bulbo, 12%, 25% y 43% para el diámetro y 30%, 52% y 78% para el peso fresco del bulbo en los niveles crecientes de 30, 60 y 90 mM de NaCl, respectivamente. Los niveles salinos crecientes se relacionaron directamente con el aumento en los valores de sólidos solubles totales y disminución en el contenido de ácido pirúvico, lo que se tradujo en un sabor más dulce y menos pungente de los bulbos.Cebolla de bulbo-Cebolla japonesa

    ENEMIGOS NATURALES DE ESTADIOS INMADUROS DE Methona confusaBUTHER, 1873 (LEPIDOPTERA: NYMPHALIDAE) EN CERRO AZUL, PANAMÁ

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    Por primera vez se reportan los enemigos naturales de los estadios inmaduros de la mariposa Methona confusa Butler, 1873 (Nymphalidae); mediante un monitoreo de ocho años continuos en Monte Fresco, colindante con Residencial Las Nubes, Cerro Azul, Provincia de Panamá, Panamá. Mediante observaciones biológicas y ecológicas en Brunfelsia grandiflora (Solanaceae), planta hospedero natural de Methona confusa se reconocieron sus enemigos naturales: los huevos son depredados por las hormigas Camponotus senex (Fr. Smith 1858); los estadios larvales son atacados por el ave Turdus grayi Bonaparte, 1838 “la casca” en el campo, y en condiciones de laboratorio la hormiga Tapinoma melanocephalum Fabricius, 1793 ataca a las larvas. El estadio de pupa atacado por avispas parasitoides del género Euplectrus sp (Eulophidae) y por hongos entomopatógenos del género Penicillium sp. (Cordycypitaceae). Consideramos que estos enemigos naturales son la causa del decrecimiento de las poblaciones silvestres de M. confusa. El ciclo biológico de Methona confusa dura aproximadamente ± 45 días, desde la eclosión de los huevos hasta la emergencia de los adultos

    Grassroots Agency: Participation and Conflict in Buenos Aires Shantytowns seen through the Pilot Plan for Villa 7 (1971–1975)

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    open access articleIn 1971, after more than a decade of national and municipal policies aimed at the top-down removal of shantytowns, the Buenos Aires City Council approved the Plan Piloto para la Relocalización de Villa 7 (Pilot Plan for the Relocation of Shantytown 7; 1971–1975, referred to as the Pilot Plan hereinafter). This particular plan, which resulted in the construction of the housing complex, Barrio Justo Suárez, endures in the collective memory of Argentines as a landmark project regarding grassroots participation in state housing initiatives addressed at shantytowns. Emerging from a context of a housing shortage for the growing urban poor and intense popular mobilizations during the transition to democracy, the authors of the Pilot Plan sought to empower shantytown residents in novel ways by: 1) maintaining the shantytown’s location as opposed to eradication schemes that relocated the residents elsewhere, 2) formally employing some of the residents for the stage of construction, as opposed to “self-help” housing projects in which the residents contributed with unpaid labor, and 3) including them in the urban and architectural design of the of the new housing. This paper will examine the context in which the Pilot Plan was conceived of as a way of re-assessing the roles of the state, the user, and housing-related professionals, often seen as antagonistic. The paper argues that residents’ fair participation and state intervention in housing schemes are not necessarily incompatible, and can function in specific social and political contexts through multiactor proposals backed by a political will that prioritizes grassroots agency

    Revista de Vertebrados de la Estación Biológica de Doñana

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    Descripción de un nuevo género y de una nueva especie Iberocypris palaciosi N.GEN.N.SO (Pisces, cyprinidae).Resultados de los censos d e aves acuáticas en Andalucía Occidental durante el invierno1978-79Interacciones en la alimentación de las larvas de dos especies de tritones. (Triturus marmoratus y Triturus boscai).Utilización del espacio en una comunidad de lacertidos del matorral mediterráneo en la Reserva Biológica de DoñanaMorfología dentaria de las liebres europeas (Lagomorpha, leporidae).El conejo, Oryctolagus cuniculus en Andalucía Occidental: Parámetros corporales y curva de crecimientoObservaciones de foca monje (Monachus monachus Herm.) en las costas del sureste de la Península Ibérica.Presencia de pejerrey Atherina (Hepsetia) boyeri, Risso 1810; Pisces ( Atherinidae) en la laguna de Zoñar (Córdoba, SO de España).Nuevas citas de la "loina" Chondrostoma (Machaerochilus) toxostoma arrigonis Stein. (pisces, cyprinidae) en EspañaRelativa subalimentación de Falco naumanni durante el periodo no reproductor en el valle del GuadalquivirComadrejas alimentandose de carroña.Agrupamientos de Alytes cisternasii bajo el mismo refugioDescripción de un nuevo género de quiróptero neotropical de la familia MolossidaeAlgunas notas sobre Platalea leucorodia en GaliciaInicidencia del murciélago hematófago Desmodus rotundus sobre los indígenas Yanomani de VenezuelaRitmo de actividad de algunos ratones de los llanos de Apure (Venezuela)Presencia del topillo campesino ibérico, Microtus arvalis asturianus Miller, 1908 en la meseta del DueroFalco columbarius EsmerejónCiconia ciconia CigüeñaNycticorax nycticorax MartinetePeer reviewe

    Single nucleotide polymorphisms in DNA repair genes as risk factors associated to prostate cancer progression

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    Background Besides serum levels of PSA, there is a lack of prostate cancer specific biomarkers. It is need to develop new biological markers associated with the tumor behavior which would be valuable to better individualize treatment. The aim of this study was to elucidate the relationship between single nucleotide polymorphisms (SNPs) in genes involved in DNA repair and prostate cancer progression.Methods A total of 494 prostate cancer patients from a Spanish multicenter study were genotyped for 10 SNPs in XRCC1, ERCC2, ERCC1, LIG4, ATM and TP53 genes. The SNP genotyping was made in a Biotrove OpenArray® NT Cycler. Clinical tumor stage, diagnostic PSA serum levels, and Gleason score at diagnosis were obtained for all participants. Genotypic and allelic frequencies were determined using the web-based environment SNPator.Results SNPs rs11615 (ERCC1) and rs17503908 (ATM) appeared as risk factors for prostate cancer aggressiveness. Patients wild homozygous for these SNPs (AA and TT, respectively) were at higher risk for developing cT2b – cT4 (OR = 2.21 (confidence interval (CI) 95% 1.47 – 3.31), p < 0.001) and Gleason scores ≥ 7 (OR = 2.22 (CI 95% 1.38 – 3.57), p < 0.001), respectively. Moreover, those patients wild homozygous for both SNPs had the greatest risk of presenting D’Amico high-risk tumors (OR = 2.57 (CI 95% 1.28 – 5.16)).Conclusions Genetic variants at DNA repair genes are associated with prostate cancer progression, and would be taken into account when assessing the malignancy of prostate cancer.This work was subsidized by a grant from the Instituto de Salud Carlos III (Ministerio de Economía y Competitividad from Spain), ID: PI12/01867. Almudena Valenciano has a grant from the Instituto Canario de Investigación del Cáncer (ICIC)

    Chagas Cardiomyopathy Manifestations and Trypanosoma cruzi Genotypes Circulating in Chronic Chagasic Patients

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    Chagas disease caused by Trypanosoma cruzi is a complex disease that is endemic and an important problem in public health in Latin America. The T. cruzi parasite is classified into six discrete taxonomic units (DTUs) based on the recently proposed nomenclature (TcI, TcII, TcIII, TcIV, TcV and TcVI). The discovery of genetic variability within TcI showed the presence of five genotypes (Ia, Ib, Ic, Id and Ie) related to the transmission cycle of Chagas disease. In Colombia, TcI is more prevalent but TcII has also been reported, as has mixed infection by both TcI and TcII in the same Chagasic patient. The objectives of this study were to determine the T. cruzi DTUs that are circulating in Colombian chronic Chagasic patients and to obtain more information about the molecular epidemiology of Chagas disease in Colombia. We also assessed the presence of electrocardiographic, radiologic and echocardiographic abnormalities with the purpose of correlating T. cruzi genetic variability and cardiac disease. Molecular characterization was performed in Colombian adult chronic Chagasic patients based on the intergenic region of the mini-exon gene, the 24Sα and 18S regions of rDNA and the variable region of satellite DNA, whereby the presence of T.cruzi I, II, III and IV was detected. In our population, mixed infections also occurred, with TcI-TcII, TcI-TcIII and TcI-TcIV, as well as the existence of the TcI genotypes showing the presence of genotypes Ia and Id. Patients infected with TcI demonstrated a higher prevalence of cardiac alterations than those infected with TcII. These results corroborate the predominance of TcI in Colombia and show the first report of TcIII and TcIV in Colombian Chagasic patients. Findings also indicate that Chagas cardiomyopathy manifestations are more correlated with TcI than with TcII in Colombia

    The Presidency and the Executive Branch in Latin America: What We Know and What We Need to Know

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    The presidential politics literature depicts presidents either as all- powerful actors or figureheads and seeks to explain outcomes accordingly. Th e president and the executive branch are nonetheless usually treated as black boxes, particularly i n developing countries, even though the presidency has evolved into an extremely complex branch of government. While these developments have been studied in the U nited States, far less i s known in other countries, particularly in Latin America, where presi dential systems have been considered the source of all goods and evils. To help close the knowledge gap and explore differences in policymaking characteristics not only between Latin America and the US but also across Latin American countries, this paper s ummarizes the vast literature on the organization and resources of the Executive Branch in the Americas and sets a research agenda for the study of Latin American presidencies.Fil: Bonvecchi, Alejandro. Universidad Torcuato Di Tella. Departamento de Ciencia Política y Estudios Internacionales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Scartascini, Juan Carlos. Banco Interamericano de Desarrollo; Estados Unido

    A collaboratively derived environmental research agenda for Galapagos

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    Galápagos is one of the most pristine archipelagos in the world and its conservation relies upon research and sensible management. In recent decades both the interest in, and the needs of, the islands have increased, yet the funds and capacity for necessary research have remained limited. It has become, therefore, increasingly important to identify areas of priority research to assist decision-making in Galápagos conservation. This study identified 50 questions considered priorities for future research and management. The exercise involved the collaboration of policy makers, practitioners and researchers from more than 30 different organisations. Initially, 360 people were consulted to generate 781 questions. An established process of preworkshop voting and three rounds to reduce and reword the questions, followed by a two-day workshop, was used to produce the final 50 questions. The most common issues raised by this list of questions were human population growth, climate change and the impact of invasive alien species. These results have already been used by a range of organisations and politicians and are expected to provide the basis for future research on the islands so that its sustainability may be enhanced. </jats:p
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