Nanocomposites: the contribution of multiscale modelling to improve the dispersion levels

Tese de Doutoramento em Ciência e Engenharia de Polímeros e Compósitos

Green's relations, regularity and abundancy for semigroups of quasi-onto transformations

Let V be an infinite-dimensional vector space and for every infinite cardinal n such that n≤dimV, let AE(V,n) denote the semigroup of all linear transformations of V whose defect is less than n. In 2009, Mendes-Gonçalves and Sullivan studied the ideal structure of AE(V,n). Here, we consider a similarly-defined semigroup AE(X,q) of transformations defined on an infinite set X. Quite surprisingly, the results obtained for sets differ substantially from the results obtained in the linear setting.

Effects of propranolol on the QT dispersion in congestive heart failure

OBJECTIVE - Studies have shown that therapy with beta-blockers reduces mortality in patients with heart failure. However, there are no studies describing the effects of propranolol on the QT dispersion in this population. The objective of this study was to assess the electrophysiological profile, mainly QT dispersion, of patients with heart failure regularly using propranolol. METHODS - Fifteen patients with heart failure and using propranolol were assessed over a period of 12 months. Twelve-lead electrocardiograms (ECG) were recorded prior to the onset of beta-blocker therapy and after 3 months of drug use. RESULTS - A significant reduction in heart rate, in QT dispersion and in QTc dispersion was observed, as was also an increase in the PR interval and in the QT interval, after the use of propranolol in an average dosage of 100 mg/day. CONCLUSION - Reduction in QT dispersion in patients with heart failure using propranolol may explain the reduction in the risk of sudden cardiac death with beta-blocker therapy, in this specific group of patients.

Arrhythmogenic cardiomyopathy of the right ventricle. Predictive value of QT interval dispersion to assess arrhythmogenic risk and sudden death

OBJECTIVE: To determine in arrhythmogenic right ventricular cardiomyopathy the value of QT interval dispersion for identifying the induction of sustained ventricular tachycardia in the electrophysiological study or the risk of sudden cardiac death. METHODS: We assessed QT interval dispersion in the 12-lead electrocardiogram of 26 patients with arrhythmogenic right ventricular cardiomyopathy. We analyzed its association with sustained ventricular tachycardia and sudden cardiac death, and in 16 controls similar in age and sex. RESULTS: (mean ± SD). QT interval dispersion: patients = 53.8±14.1ms; control group = 35.0±10.6ms, p=0.001. Patients with induction of ventricular tachycardia: 52.5±13.8ms; without induction of ventricular tachycardia: 57.5±12.8ms, p=0.420. In a mean follow-up period of 41±11 months, five sudden cardiac deaths occurred. QT interval dispersion in this group was 62.0±17.8, and in the others it was 51.9±12.8ms, p=0.852. Using a cutoff > or = 60ms to define an increase in the degree of the QT interval dispersion, we were able to identify patients at risk of sudden cardiac death with a sensitivity of 60%, a specificity of 57%, and positive and negative predictive values of 25% and 85%, respectively. CONCLUSION: Patients with arrhythmogenic right ventricular cardiomyopathy have a significant increase in the degree of QT interval dispersion when compared with the healthy population. However it, did not identify patients with induction of ventricular tachycardia in the electrophysiological study, showing a very low predictive value for defining the risk of sudden cardiac death in the population studied.

Reduction of QTc interval dispersion. Potential mechanism of cardiac protection of pyridostigmine bromide

OBJECTIVE: Parasympathetic dysfunction is an independent risk factor in individuals with coronary artery disease, and cholinergic stimulation is a potential therapeutical option. We determined the effects of pyridostigmine bromide, a reversible anticholinesterase agent, on electrocardiographic variables of healthy individuals. METHODS: We carried out a cross-sectional, double blind, randomized, placebo-controlled study. We obtained electrocardiographic tracings in 12 simultaneous leads of 10 healthy young individuals at rest before and after oral administration of 45 mg of pyridostigmine or placebo. RESULTS: Pyridostigmine increased RR intervals (before: 886±27 ms vs after: 1054±37 ms) and decreased QTc dispersion (before: 72±9ms vs after: 45±3ms), without changing other electrocardiographic variables (PR segment, QT interval, QTc, and QT dispersion). CONCLUSION: Bradycardia and the reduction in QTc dispersion induced by pyridostigmine may effectively represent a protective mechanism if these results can be reproduced in individuals with cardiovascular diseases.

A voyage to the islands Madera, Barbados, Nieves, S. Christophers and Jamaica : with the natural history of the herbs and trees, four-footed beasts, fishes, birds, insects, reptiles, &c. of the last of those islands; to which is prefix'd, an introduction, wherein is an account of the inhabitants, air, waters, diseases, trade, &c. of that place, with some relations concerning the neighbouring continent, and islands of America. Illustrated with figures of the things described, which have not been heretofore engraved. In large copper-plates as big as the life /

Vol. 2

A voyage to the islands Madera, Barbados, Nieves, S. Christophers and Jamaica : with the natural history of the herbs and trees, four-footed beasts, fishes, birds, insects, reptiles, &c. of the last of those islands; to which is prefix'd, an introduction, wherein is an account of the inhabitants, air, waters, diseases, trade, &c. of that place, with some relations concerning the neighbouring continent, and islands of America. Illustrated with figures of the things described, which have not been heretofore engraved. In large copper-plates as big as the life /

Vol. 1

Patrones dinámicos de abundancia y dispersión de una plaga en un paisaje heterogéneo. Dynamic patterns of abundance and dispersion of a pest in a heterogeneous landscape.

El desarrollo de conocimiento empírico sobre cómo la heterogeneidad espacial de un paisaje afecta los patrones de movimiento de una especie animal es considerado una prioridad para el manejo y la conservación de las especies y sus hábitats. En el caso de los insectos plaga, estos estudios resultan importantes ya que aportan las bases teóricas y empíricas fundamentales para su manejo. La persistencia de éstas especies en un paisaje modificado depende de la interrelación entre procesos ecológicos y la estructura del paisaje, tales como la interacción entre especies, la disponibilidad de parches hábitat y la influencia de las prácticas de manejo. El análisis de éstos procesos en un agroecosistema permite simplificar los modelos de heterogeneidad espacial, debido a que los lotes de cultivo son internamente homogéneos y los disturbios antropogénicos generalmente ocurren a la escala de parche, permitiendo determinar las respuestas de los insectos a dicha escala. La alfalfa (Medicago sativa) es un recurso fundamental para la producción agropecuaria y en Argentina, es el recurso forrajero más importante, constituyendo la base de la producción ganadera del país. Actualmente se cultivan alrededor de 5 millones de hectáreas, de las cuales un millón se siembran en la provincia de Córdoba. Además, cumple un rol importante en la sustentabilidad de los sistemas de producción por su función de recuperación de la fertilidad y estabilidad edáfica. La isoca de la alfalfa (Colias lesbia) es la plaga principal del cultivo, produciendo en promedio la pérdida de un corte por año. La hipótesis principal de nuestro trabajo es que los patrones de abundancia y movilidad de la isoca de la alfalfa son afectados por la estructura del paisaje y las prácticas de manejo. Los objetivos específicos del proyecto son: (a) Establecer el efecto de la estructura del paisaje y y el manejo del cultivo en la abundancia de los distintos estadios de Colias lesbia. (b) Determinar los patrones de dispersión de Colias lesbia en relación a la heterogeneidad espacial del paisaje (c) Generar un modelo predictivo de la abundancia de Colias lesbia según la estructura espacial del paisaje, el clima y el manejo del cultivo. (d) Desarrollar un conjunto de recomendaciones de manejo a escala regional para el control de la isoca de la alfalfa. Para ello se elegirán lotes de alfalfa en la región este de la provincia de Córdoba, en el departamento de San Justo, donde se realizará un relevamiento inicial del área de estudio y se dialogará con los productores. Paralelamente, se realizará una clasificación supervisada del área de estudio a partir de escenas de imágenes Landsat TM. En los parches seleccionados, durante 3 años y durante los meses de verano, se muestrearán quincenalmente los distintos estadios de Colias lesbia. Se realizarán análisis de correlación y regresión entre las variables independientes (métricas de la configuración y dinámica del paisaje) y las variables dependientes, (abundancia media de los diferentes estadios de las poblaciones). Asimismo, se realizarán experimentos de marcado-liberación-recaptura para determinar cómo el movimiento de la especie depende de la estructura del paisaje. Para modelar el movimiento inherente de la especie se combinará la información obtenida en el campo con un modelo de difusión utilizando métodos bayesianos. Se espera obtener modelos que permitan comprender los mecanismos que generan los patrones observados. Con esta información se propondrán lineamientos generales y específicos para un manejo de la isoca de la alfalfa a escala regional. En tal sentido, se espera aportar información para restringir la dispersión de la plaga, y reducir los costos y perjuicios del control químico que podrían evitarse con la aplicación de prácticas de manejo integrado y de "manejo de área" que minimicen el impacto de la plaga como también contribuir al conocimiento general de la ecología de insectos.

Prácticas comunicativas forenses: Las relaciones intertextuales en el examen de testigos. Forensic communicative practices: intertextual relations in examination of witnesses.

Inscripto en el análisis del discurso interaccional de tradición angloamericana y optando por un abordaje metodológico etnográfico, este proyecto plantea investigar las relaciones entre textos orales y entre textos orales y escritos vinculados en cadenas textuales en un acontecimiento comunicativo institucional en el que tales relaciones tienen consecuencias directas en la confiabilidad de la información e intervienen en la construcción del conocimiento oficial. La situación comunicativa elegida es el examen y el contraexamen de testigos comunes durante procesos penales orales, de formato común no abreviado, en la jurisdicción de Córdoba capital. En las interacciones verbales con litigantes y jueces en las que emerge el testimonio se ponen en juego otros textos orales (en forma de citas de lo dicho antes por el mismo testigo u otras personas, referencias a rumores u opiniones colectivas, etc.) y textos escritos (actas de secuestro, informes periciales, actas de las declaraciones testimoniales en la etapa de instrucción, etc.). El foco de atención son las prácticas asociadas a la intertextualidad puesto que condicionan el carácter de la prueba testimonial producida ante el juzgador. Postulamos que los litigantes despliegan tácticas locales y estrategias globales reconocibles y recurrentes vinculadas al tratamiento de diversas categorías de textos previos. Además, planteamos averiguar si la participación de los jueces en interacción con los testigos es de suficiente injerencia como para ser un modo importante de generación de prueba testimonial. El enfoque metodológico general es etnográfico y analíticodiscursivo. Se seleccionará una causa por delito grave, se presenciará el debate en la cámara y se registrará el audio de todas las audiencias. Los datos a analizar serán los segmentos en las interacciones en los que se incorpora la lectura o se cita las actas de las declaraciones indagatorias o testimoniales anteriores, y los segmentos en los que se requiere, en calidad de prueba testimonial, la reproducción de dichos. Se procederá a partir de los detalles de la superficie textual y la pragmática de los intercambios y aprovechando el valor heurístico del concepto de voz, buscando identificar patrones recurrentes y los mecanismos generales que los rigen. Sobre esa base, se considerarán los intercambios verbales como interacción social que emerge moldeada por condiciones situacionales e institucionales y otros factores, tales como la incidencia de la pertenencia a grupos sociales o profesionales. Con el estudio se obtendrá una visión de prácticas cotidianas asociadas a la intertextualidad que son de crucial importancia para el carácter de la prueba testimonial producida ante el juzgador. Este paso nos acercará a conocer cómo se lleva a cabo efectivamente la administración de justicia penal y permitirá valorar los patrones de conducta a la luz de las normas procesales. In line with the Anglo-American tradition of situated discourse analysis, this project aims at tracing the links between oral texts and between oral and written texts related in textual chains which are present in an institutional event in which such relations have a direct consequence on the reliability of the information given and have an impact on the construction of what counts as official knowledge. The communicative situation under study is that of the direct and cross-examination of lay witnesses during a criminal trial in the city of Córdoba. During the face-to-face interactions between trial lawyers and judges in which the testimony takes place, other oral texts and written texts get incorporated. The focus of this research is centered on practices of intertextuality as they condition the nature of the oral evidence produced. It is argued that trial lawyers use recurrent local tactics and global strategies that are related to the treatment given to different categories of previous texts. Another aim of this study is to examine if judge’s interventions have an impact on the generation of the oral evidence. The data will come from a criminal trial that will be audio-taped in its entirety. Ethnographic observations of a criminal trial will be made. The focus of analysis will be on segments of interactions in which previous texts are read aloud or incorporated as quotes. After carrying out a detailed analysis of the surface of texts and the pragmatics of the exchanges, recurrent patterns and the general mechanisms that condition their emergence will be described. In this way, verbal exchanges will be considered social interactions that unfold conditioned by situational, institutional and social factors. This study will examine the relationship between intertextuality and the institutional practice of providing oral evidence. This will help understand how justice is actually administered and how patterns of behavior are valued according to institutional norms.

On the status and relations of Crocodylus mindorensis.

v.33:no.5(1956)

Intra-relations of African canaries, genus Serinus [by] Austin L. Rand.

v.51:no.9(1968)

Molecular phylogenies, chromosomes and dispersion in Brazilian akodontines (Rodentia, Sigmodontinae)

A new molecular phylogeny for akodontine rodents from Brazil was proposed. The phylogenetic tree was enriched with the area of occurrence and with information on the karyotype of the samples. Based on this enriched tree, and with a described methodology, hypotheses were proposed on the karyotype and area of occurrence of the ancestors of each Clade. Thus it was possible to discuss hypotheses on chromosome evolution of the group, and on dispersion events from the "area of original differentiation" of akodontines in the Andes. Chromosome evolution started with high diploid numbers (2n=52) and showed a tendency to reduction (until 2n=14 in more recent clades). Independent side-branches of the tree showed 2n reduction and in one case the 2n increased. At least four dispersion events from the Andes down to South-eastern Brazil were proposed. The results should suggest the direction of new studies on comparative karyology.

Ecological relations between mangrove leaf litter and the spatial distribution of the gastropod Melampus coffeus in a fringe mangrove forest

Leaf litter represents a food source to many organisms that may directly contribute to organic matter decomposition. In addition, the physical presence of these vegetal detritus contributes for the modification of some environmental areas and produce microhabitats that may act as a refuge against predators and desiccation for many animals. The pulmonate gastropod Melampus coffeus (Linnaeus, 1758) (Ellobiidae) is a very common specie in Atlantic Coast mangrove forests and feeds on fallen mangrove leaves. It was hypothesized that the spatial distribution of Melampus coffeus is directly affected by mangrove leaf litter biomass deposition. Thus, this research aimed at evaluating the spatial distribution of these gastropods in relation to the biomass of mangrove leaf litter through a twelve-month period. The study area was established in the middle estuary of Pacoti River, state of Ceará, Brazil where two adjacent zones with different topographic profiles were determined. Samples of Melampus coffeus and leaf litter were collected monthly, throughout a year, from the mangrove ground surface. The results indicated that the presence of twigs in mangrove litter favor the occupation by smaller individuals of M. coffeus, probably because smaller individuals are more susceptible to predator attacks and desiccation than larger ones, and twigs and branches may provide a safe microhabitat.

Science, technology, and American diplomacy : an extended study of the interactions of science and technology with United States foreign policy / Committee on International Relations, U.S. House of Representatives.

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