Morpho-physiological analysis of adaptive responses of common bean (Phaseolus vulgaris L.) to drought stress. Thesis (Ph.D.)

Common bean (Phaseolus vulgaris L.) is the most important food legume in the diet of poor people in the tropics. This legume is cultivated by small farmers and is usually exposed to unfavorable conditions with minimum use of inputs. Drought and low soil fertility, especially phosphorus (P) and nitrogen (N) deficiencies, are major limitations to bean yield in smallholder systems. Beans can derive part of their required N from the atmosphere through symbiotic nitrogen fixation (SNF). Drought stress severely limits SNF ability of plants. Identification of traits associated with drought resistance contributes to improving the process of designing bean genotypes adapted to these conditions. Field studies were conducted at the International Center for Tropical Agriculture (CIAT), Palmira, Colombia to determine the relationship between grain yield and different parameters in elite lines selected for drought resistance over the past decade. The selected traits were effective use of water (EUW), canopy biomass, remobilization of photosynthates to grain (pod partitioning index, harvest index and pod harvest index) and SNF ability. Moreover, in field trials we also validated the use of 15N natural abundance in grain tissue to quantify phenotypic differences in SNF ability for its implementation in breeding programs aiming to improve SNF in common bean. Carbon isotope discrimination (CID) was used for estimation of water use efficiency (WUE) and effective use of water (EUW). A set of 36 bean genotypes belonging to the Middle American gene pool were evaluated under field conditions with two levels of water supply (irrigated and rainfed) over two seasons. Additionally, a greenhouse study was conducted at CIAT using plastic cylinders with soil inserted into PVC pipes, to determine the relationship between grain yield and different root parameters such as total root length, fine root production and visual root growth rate in same group of elite lines under drought stress. Eight bean lines (NCB 280, NCB 226, SEN 56, SCR 2, SCR 16, SMC 141, RCB 593 and BFS 67) were identified as resistant to drought stress. Resistance to terminal drought stress was positively associated with EUW combined with a deeper and vigorous root system, better plant growth, and superior mobilization of photosynthates to pod and seed production, but negatively associated with days to flowering and days to physiological maturity. Based on phenotypic differences in CID, leaf stomatal conductance, canopy biomass and grain yield under drought stress, the tested lines were classified into two groups, water savers and water spenders. These groups also differ in their root characteristics, water spenders with a vigorous and deeper root system and water savers genotypes with a moderate to shallow root system and more presence of fine roots. We used 15N natural abundance method to compare SNF ability estimated from shoot tissue sampled at mid-pod filling growth stage vs. grain tissue sampled at harvest. The results showed a significant positive correlation between nitrogen derived from the atmosphere (Ndfa), estimated using shoot tissue at mid-pod filling, and Ndfa estimated using grain tissue at harvest. The method showed phenotypic variability in SNF ability under both drought and irrigated conditions. A significant reduction in SNF ability was observed under drought stress. We suggest that the method of estimating Ndfa using grain tissue (Ndfa-G) can be applied in bean breeding programs to improve SNF ability. Using this method of Ndfa-G, we identified four bean lines (RCB 593, SEA 15, NCB 226 and BFS 29) that combine greater SNF ability with higher grain yield under drought stress. These lines could serve as potential parents to further improve SNF ability of common bean. Better SNF ability under drought stress was related with superior presence of thick roots. Superior N uptake from the soil was associated with a large root system with more presence of fine roots. Pod harvest index, grain CID and Ndfa using grain tissue could be a useful selection criterion in breeding programs to select for drought resistance in common bean

Simulating chemistry using quantum computers

The difficulty of simulating quantum systems, well-known to quantum chemists, prompted the idea of quantum computation. One can avoid the steep scaling associated with the exact simulation of increasingly large quantum systems on conventional computers, by mapping the quantum system to another, more controllable one. In this review, we discuss to what extent the ideas in quantum computation, now a well-established field, have been applied to chemical problems. We describe algorithms that achieve significant advantages for the electronic-structure problem, the simulation of chemical dynamics, protein folding, and other tasks. Although theory is still ahead of experiment, we outline recent advances that have led to the first chemical calculations on small quantum information processors.Comment: 27 pages. Submitted to Ann. Rev. Phys. Che

Engineering directed excitonic energy transfer

We provide an intuitive platform for engineering exciton transfer dynamics. We show that careful consideration of the spectral density, which describes the system-bath interaction, leads to opportunities to engineer the transfer of an exciton. Since excitons in nanostructures are proposed for use in quantum information processing and artificial photosynthetic designs, our approach paves the way for engineering a wide range of desired exciton dynamics. We carefully describe the validity of the model and use experimentally relevant material parameters to show counter-intuitive examples of a directed exciton transfer in a linear chain of quantum dots

The confrontation between Mayans and the Iriarte with respect to the Latin grammars

En la historiografía tradicional, y a propósito del pleito de las gramáticas latinas, generalmente se ha presentado a Mayans como una víctima inerme de las intrigas de los Iriarte, y esta imagen coincide con la que don Gregorio a menudo presentó de sí mismo. Sin embargo, un análisis de este enfrentamiento en relación con las otras polémicas en las que resultó implicado el valenciano pone de manifiesto que los hechos deben ser interpretados en un contexto más amplio y más complejo que trasciende los enfrentamientos y las meras ambiciones personales, y que también caracteriza a la sociedad y la cultura españolas del siglo XVIII: el reformismo borbónico, la renovación de las enseñanzas del latín, el clientelismo político y la lucha de facciones y las nuevas formas de socialización de los literatos. Esta interpretación sugiere la necesidad de una historiografía de la lingüística de carácter hermenéutico.In traditional historiography, and with regard to the litigation of the Latin grammars, usually presented to Mayans as defenseless victims of the machinations of the Iriarte, and this picture agrees with that Don Gregorio often presented itself. However, an analysis of this conflict in relation to the other controversies in which it was implied the valencian shows that the facts must be interpreted in a broader context and more complex that transcends mere confrontations and personal ambitions, and that also characterizes the Spanish society and culture of the eighteenth century: the Bourbon reforms, the renewal of the teaching of Latin, the political patronage and factional fighting and the new forms of socialization of the writers

Concepciones de ?tica y valores de los estudiantes del grado 11 en dos intituciones educativas Alberto Santofimio Caicedo de Ibagu? y el colegio Colombo Ingl?s del Huila en Neiva

96 p. Recurso Electr?nicoEl presente trabajo investigativo se ocup? de la identificaci?n y an?lisis de los conceptos de ?tica y valores que tienen los estudiantes del grado once (11) de las instituciones educativas Alberto Santofimio Caicedo y El Colegio Colombo Ingl?s del Huila. De ah? que se aplicar?n dos encuestas, la primera para identificar los conceptos de los estudiantes frente a la ?tica y los valores, dise?ada bajo tres constructos te?ricos: ?tica grecorromana, ?tica moderna, ?tica contempor?nea y una segunda dise?ada por categor?as: Conciencia de Grupo Solidaridad y Bien Com?n (CGSBC), Conciencia de Legalidad (CL) y Conciencia de Compromiso y Responsabilidad (CCR) con el prop?sito de poder caracterizar sus conceptos. En consecuencia se logr? identificar que los estudiantes de las dos instituciones identifican el concepto de ?tica desde la l?nea de pensamiento filos?fico moderno y una caracterizaci?n de la ?tica en las tres categor?as (CGSBC, CL, CCR) tendiente a una frecuencia de decisi?n (siempre, casi siempre, pocas veces, nunca) como casi siempre. Aun as?, con los resultados y an?lisis obtenidos se evidencio que su teor?a y caracterizaci?n son contarios a la vivencia relacional de los estudiantes en su ambiente escolar. Por consiguiente se dise?aron dos momentos de formaci?n y recomendaciones basados en el referente te?rico de la presente investigaci?n, donde se propuso un acercamiento que considero el contexto hist?rico cultural de los educandos y su desarrollo moral evolutivo, que busco una formaci?n en ?tica y valores contempor?nea, pertinente y que a su vez contribuyera a los procesos de afrontamiento de las diferentes problem?ticas de convivencia escolar que afrontan estas dos instituciones. Para tales efectos esta investigaci?n implemento como metodolog?a: Investigaci?n acci?n, acompa?ado de un enfoque cualitativo y un dise?o transversal reflexivo. Por esta raz?n se consider? el contexto inmediato de los discentes en la elaboraci?n, aplicaci?n de instrumentos de recolecci?n de informaci?n y los momentos de formaci?n.The purpose of this research was to reflect slightly upon ethics and values concepts that eleventh graders have. The aim of this is to restate and foster a healthy living together among youngsters at school. Ethics and values concept were determined and characterised based on a selected theoretical foundation that underpinned this final paper. The type of research conducted on this experience was an Action Research project. Surveys and workshops of formation were designed and applied in every research stage. These workshops relied on theory to practice. The sample population was formed by ninety (90) pupils from Alberto Santofimio Caicedo and Colombo Ingles del Huila schools. From the results emerged that students had bias in ethics and values concepts and viewpoints. Students had an unclear vision of Ancient, Modern and Contemporary concepts in ethics and values. The formation workshops were designed and developed in order to talk about socio-critic and light ethics aiming at fostering student?s critical thinking towards situations in their living together where ethics and values should be practiced. Finally, some recommendations were given to each school, mainly in their ethics and values subjects as an improvement plan regarding to themes such as interpersonal relations, acceptance of limits, respect of other?s difference and dignity for the benefit of a healthy living together in their social surrounding. Key words: Ethics, values, concepts, characterization, school context, living together, action research, improvement plan, ethics and values study plan and recommendations

Phenotyping common beans for adaptation to drought: protocol for field evaluation

This protocol was provided for the identification of phenotypic differences in drought resistance in common beans (Phaseolus vulgaris L.). It is available in both PDF and photo gallery format with the aim of providing visiting students and researchers with a consultation document they can use to answer questions about our in-house methodologies

Estudio comparativo de dos métodos de radiografías forzadas para detectar la insuficiencia del ligamento cruzado anterior

En 32 pacientes con rotura unilateral de ligamento cruzado anterior (LCA) comprobada mediante artroscopia se efectuó previamente una radiografía forzada de ambas rodillas para estudiar el desplazamiento anterior de la tibia. Cada paciente fue estudiado mediante dos métodos diferentes, Lachman activo radiológico (LAR) y TelosR. Se asumió el diagnóstico radiológico de inestabilidad cuando la diferencia en el desplazamiento entre la rodilla lesionada y su control fue superior a 3 mm. Los resultados demuestran que la diferencia media del desplazamiento entre la rodilla lesionada y la normal fue superior a 3 mm con ambos métodos. En el lado interno 3,7 ± 3,7 mm con el LAR y 4,8 ± 5,8 mm con el Telos (diferencias no significativas). En el lado externo esta diferencia fue de 4,3 ± 4,7 nun con el LAR y de 6,8 ± 6 mm con el Telos (p < 0,05). A pesar de estos resultados, ambos métodos mostraron una sensibilidad para la detección de la insuficiencia ligamentosa inferior al 70%, lo que cuestiona su valor para el diagnóstico de la misma.In a prospective study, 32 patients with arthroscopically proved anterior cruciate ligament rupture were previously stressradiographied on both knees through two methods: the quadriceps-contraction technique (QCT) and the TelosR device. Instability was assumed when radiological differential displacement between injured and normal knee was greated than 3 mm. Results showed that this differential displacement was greater than 3 mm with both methods: 3,7 ± 3,7 mm v.s. 4,8 ± 5,8 mm in the medial side (differences not significant) and 4,3 ± 4,7 mm v.s. 6,8 ± 6 mm (p < 0.05) for the lateral side with the QCT and TelosR respectively. In spite of these differences, both methods showed a sensitivity lower than 70%

Efeito de diferentes taxas de ventilação no desempenho de leitões na maternidade.

Determinar a influencia de diferentes taxas de renovação do ar no desempenho de leitões e no acondicionamento ambiental da maternidade.1987Resumo