378 research outputs found
The Origins and Development of John F. Kennedy and Lyndon B. Johnson\u27s Perceptions of American Foreign Policy toward East Asia
The administrations of John F. Kennedy and Lyndon B. Johnson focused extensively on foreign affairs in East Asia related to China, Laos, and Vietnam. Examining the development of their respective perceptions proved instrumental in comprehending their approaches to the geopolitics of the region. The overall structure of this thesis includes an analysis of their tenure in Congress, a breakdown of the first-half of Kennedy’s presidency, an emphasis on the transition period between Kennedy and Johnson, an examination of Johnson’s presidency, and concluding with a detailed comparison of their foreign policy toward East Asia. Their differing perceptions to the regional geopolitics proved essential in shaping the respective legacies of their administrations
Reporte de formación complementaria
El objetivo de este documento es describir el trabajo de formación complementaria realizado en el área de Sistemas Embebidos. La selección de los proyectos presentados representa una serie de conceptos y metodologías que reflejan las necesidades actuales de la industria. En primer lugar, se analiza una implementación multi-core de un generador de señal PWM en donde se cubre el concepto clave de la distribución de tareas primarias y secundarias entre diferentes elementos de procesamiento de un mismo MCU. El segundo proyecto hace nuevamente uso del concepto multi-core y, a la vez, nos pone en primer contacto con uno de los protocolos de comunicación más importantes, especialmente en la industria automotriz, el protocolo CAN. Finalmente, el último trabajo presentado en este documento cubre las bases de la implementación de “schedulers”, concepto y metodología fundamental en el diseño e implementación de sistemas operativos de tiempo real.Consejo Nacional de Ciencia y Tecnologí
toward modeling kinetics of biomolecular complexes
In order to advance the mission of in silico cell biology, modeling the interactions of large and complex biological systems becomes increasingly relevant. The combination of molecular dynamics (MD) and Markov state models (MSMs) have enabled the construction of simplified models of molecular kinetics on long timescales. Despite its success, this approach is inherently limited by the size of the molecular system. With increasing size of macromolecular complexes, the number of independent or weakly coupled subsystems increases, and the number of global system states increase exponentially, making the sampling of all distinct global states unfeasible. In this work, we present a technique called Independent Markov Decomposition (IMD) that leverages weak coupling between subsystems in order to compute a global kinetic model without requiring to sample all combinatorial states of subsystems. We give a theoretical basis for IMD and propose an approach for finding and validating such a decomposition. Using empirical few-state MSMs of ion channel models that are well established in electrophysiology, we demonstrate that IMD can reproduce experimental conductance measurements with a major reduction in sampling compared with a standard MSM approach. We further show how to find the optimal partition of all-atom protein simulations into weakly coupled subunits
Genetic Evidence for Multiple Sources of the Non-Native Fish Cichlasoma urophthalmus (Günther; Mayan Cichlids) in Southern Florida
The number and diversity of source populations may influence the genetic diversity of newly introduced populations and affect the likelihood of their establishment and spread. We used the cytochrome b mitochondrial gene and nuclear microsatellite loci to identify the sources of a successful invader in southern Florida, USA, Cichlasoma urophthalmus (Mayan cichlid). Our cytochrome b data supported an introduction from Guatemala, while our microsatellite data suggested movement of Mayan Cichlids from the upper Yucatán Peninsula to Guatemala and introductions from Guatemala and Belize to Florida. The mismatch between mitochondrial and nuclear genomes suggests admixture of a female lineage from Guatemala, where all individuals were fixed for the mitochondrial haplotype found in the introduced population, and a more diverse but also relatively small number of individuals from Belize. The Florida cytochrome b haplotype appears to be absent from Belize (0 out of 136 fish screened from Belize had this haplotype). Genetic structure within the Florida population was minimal, indicating a panmictic population, while Mexican and Central American samples displayed more genetic subdivision. Individuals from the Upper Yucatán Peninsula and the Petén region of Guatemala were more genetically similar to each other than to fish from nearby sites and movement of Mayan Cichlids between these regions occurred thousands of generations ago, suggestive of pre-Columbian human transportation of Mayan Cichlids through this region. Mayan Cichlids present a rare example of cytonuclear disequilibrium and reduced genetic diversity in the introduced population that persists more than 30 years (at least 7–8 generations) after introduction. We suggest that hybridization occurred in ornamental fish farms in Florida and may contribute their establishment in the novel habitat. Hybridization prior to release may contribute to other successful invasions
Genetic Evidence for Multiple Sources of the Non-Native Fish \u3ci\u3eCichlasoma urophtalmus\u3c/i\u3e (Günther; Mayan Cichlids) in Southern Florida
The number and diversity of source populations may influence the genetic diversity of newly introduced populations and affect the likelihood of their establishment and spread. We used the cytochrome b mitochondrial gene and nuclear microsatellite loci to identify the sources of a successful invader in southern Florida, USA, Cichlasoma urophthalmus (Mayan cichlid). Our cytochrome b data supported an introduction from Guatemala, while our microsatellite data suggested movement of Mayan Cichlids from the upper Yucatán Peninsula to Guatemala and introductions from Guatemala and Belize to Florida. The mismatch between mitochondrial and nuclear genomes suggests admixture of a female lineage from Guatemala, where all individuals were fixed for the mitochondrial haplotype found in the introduced population, and a more diverse but also relatively small number of individuals from Belize. The Florida cytochrome b haplotype appears to be absent from Belize (0 out of 136 fish screened from Belize had this haplotype). Genetic structure within the Florida population was minimal, indicating a panmictic population, while Mexican and Central American samples displayed more genetic subdivision. Individuals from the Upper Yucatán Peninsula and the Petén region of Guatemala were more genetically similar to each other than to fish from nearby sites and movement of Mayan Cichlids between these regions occurred thousands of generations ago, suggestive of pre-Columbian human transportation of Mayan Cichlids through this region. Mayan Cichlids present a rare example of cytonuclear disequilibrium and reduced genetic diversity in the introduced population that persists more than 30 years (at least 7–8 generations) after introduction. We suggest that hybridization occurred in ornamental fish farms in Florida and may contribute their establishment in the novel habitat. Hybridization prior to release may contribute to other successful invasions
Exposure to arsenic in drinking water is associated with increased prevalence of diabetes: a cross-sectional study in the Zimapán and Lagunera regions in Mexico
<p>Abstract</p> <p>Background</p> <p>Human exposures to inorganic arsenic (iAs) have been linked to an increased risk of diabetes mellitus. Recent laboratory studies showed that methylated trivalent metabolites of iAs may play key roles in the diabetogenic effects of iAs. Our study examined associations between chronic exposure to iAs in drinking water, metabolism of iAs, and prevalence of diabetes in arsenicosis-endemic areas of Mexico.</p> <p>Methods</p> <p>We used fasting blood glucose (FBG), fasting plasma insulin (FPI), oral glucose tolerance test (OGTT), glycated hemoglobin (HbA1c), and insulin resistance (HOMA-IR) to characterize diabetic individuals. Arsenic levels in drinking water and urine were determined to estimate exposure to iAs. Urinary concentrations of iAs and its trivalent and pentavalent methylated metabolites were measured to assess iAs metabolism. Associations between diabetes and iAs exposure or urinary metabolites of iAs were estimated by logistic regression with adjustment for age, sex, hypertension and obesity.</p> <p>Results</p> <p>The prevalence of diabetes was positively associated with iAs in drinking water (OR 1.13 per 10 ppb, p < 0.01) and with the concentration of dimethylarsinite (DMAs<sup>III</sup>) in urine (OR 1.24 per inter-quartile range, p = 0.05). Notably, FPI and HOMA-IR were negatively associated with iAs exposure (β -2.08 and -1.64, respectively, p < 0.01), suggesting that the mechanisms of iAs-induced diabetes differ from those underlying type-2 diabetes, which is typically characterized by insulin resistance.</p> <p>Conclusions</p> <p>Our study confirms a previously reported, but frequently questioned, association between exposure to iAs and diabetes, and is the first to link the risk of diabetes to the production of one of the most toxic metabolites of iAs, DMAs<sup>III</sup>.</p
La información financiera. Su comparabilidad en el entorno inflacionario de las medianas empresas
Es objetivo de este artículo exponer los elementos conceptuales básicos para realizar la comparación temporal de la información en los estados financieros. Se abordó la comparabilidad como una de las características cualitativas de la información financiera. Se tuvo como premisa el reconocimiento de las transacciones, transformaciones internas y eventos para comparar los estados financieros de las medianas empresas en el tiempo. Se enunciaron además los efectos de la inflación en la información financiera. El índice de precios al consumidor resulta insuficiente como técnica exclusiva para la reexpresión y la inflación; aunque despreciable en el ámbito macroeconómico, afecta en la microeconomía y es necesario para la toma de decisiones empresariales
Transcriptome analyses throughout chili pepper fruit development reveal novel insights into the domestication process
Chili pepper (Capsicum spp.) is an important crop, as well as a model for fruit development studies and domestication. Here, we performed a time-course experiment to estimate standardized gene expression profiles with respect to fruit development for six domesticated and four wild chili pepper ancestors. We sampled the transcriptomes every 10 days from flowering to fruit maturity, and found that the mean standardized expression profiles for domesticated and wild accessions significantly differed. The mean standardized expression was higher and peaked earlier for domesticated vs. wild genotypes, particularly for genes involved in the cell cycle that ultimately control fruit size. We postulate that these gene expression changes are driven by selection pressures during domestication and show a robust network of cell cycle genes with a time shift in expression, which explains some of the differences between domesticated and wild phenotypes
Epigenetic Changes in Individuals with Arsenicosis
Inorganic arsenic (iAs) is an environmental toxicant currently poisoning millions of people worldwide, and chronically exposed individuals are susceptible to arsenicosis or arsenic poisoning. Using a state-of-the-art technique to map the methylomes of our study subjects, we identified a large interactome of hypermethylated genes that are enriched for their involvement in arsenic-associated diseases, such as cancer, heart disease, and diabetes. Notably, we have uncovered an arsenic-induced tumor suppressorome, a complex of 17 tumor suppressors known to be silenced in human cancers. This finding represents a pivotal clue in unraveling a possible epigenetic mode of arsenic-induced disease
Metastable liquid lamellar structures in binary and ternary mixtures of Lennard-Jones fluids
We have carried out extensive equilibrium molecular dynamics (MD) simulations
to investigate the Liquid-Vapor coexistence in partially miscible binary and
ternary mixtures of Lennard-Jones (LJ) fluids. We have studied in detail the
time evolution of the density profiles and the interfacial properties in a
temperature region of the phase diagram where the condensed phase is demixed.
The composition of the mixtures are fixed, 50% for the binary mixture and
33.33% for the ternary mixture. The results of the simulations clearly indicate
that in the range of temperatures K, --in the scale of
argon-- the system evolves towards a metastable alternated liquid-liquid
lamellar state in coexistence with its vapor phase. These states can be
achieved if the initial configuration is fully disordered, that is, when the
particles of the fluids are randomly placed on the sites of an FCC crystal or
the system is completely mixed. As temperature decreases these states become
very well defined and more stables in time. We find that below K,
the alternated liquid-liquid lamellar state remains alive for 80 ns, in the
scale of argon, the longest simulation we have carried out. Nonetheless, we
believe that in this temperature region these states will be alive for even
much longer times.Comment: 18 Latex-RevTex pages including 12 encapsulated postscript figures.
Figures with better resolution available upon request. Accepted for
publication in Phys. Rev. E Dec. 1st issu
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