Fast genetic mapping of complex traits in C. elegans using millions of individuals in bulk.

Genetic studies of complex traits in animals have been hindered by the need to generate, maintain, and phenotype large panels of recombinant lines. We developed a new method, C. elegans eXtreme Quantitative Trait Locus (ceX-QTL) mapping, that overcomes this obstacle via bulk selection on millions of unique recombinant individuals. We use ceX-QTL to map a drug resistance locus with high resolution. We also map differences in gene expression in live worms and discovered that mutations in the co-chaperone sti-1 upregulate the transcription of HSP-90. Lastly, we use ceX-QTL to map loci that influence fitness genome-wide confirming previously reported causal variants and uncovering new fitness loci. ceX-QTL is fast, powerful and cost-effective, and will accelerate the study of complex traits in animals

Switchgrass Cultivar/Ecotype Selection and Management for Biofuels in the Upper Southeast USA

Switchgrass (Panicum virgatum L.), a perennial warm-season grass indigenous to the eastern USA, has potential as a biofuels feedstock. The objective of this study was to investigate the performance of upland and lowland switchgrass cultivars under different environments and management treatments. Four cultivars of switchgrass were evaluated from 2000 to 2001 under two management regimes in plots established in 1992 at eight locations in the upper southeastern USA. Two management treatments included 1) a single annual harvest (in late October to early November) and a single application of 50 kg N/ha/yr and 2) two annual harvests (in midsummer and November) and a split application of 100 kg N/ha/yr. Biomass yields averaged 15 Mg/ha/yr and ranged from 10 to 22 Mg/ha/yr across cultivars, managements, locations, and years. There was no yield advantage in taking two harvests of the lowland cultivars (Alamo and Kanlow). When harvested twice, upland cultivars (Cave-in-Rock and Shelter) provided yields equivalent to the lowland ecotypes. Tiller density was 36% lower in stands cutting only once per year, but the stands appeared vigorous after nine years of such management. Lowland cultivars and a one-cutting management (after the tops have senesced) using low rates of applied N (50 kg/ha) are recommended

A quantitative analysis of the effects of tariff and non-tariff barriers on U.S. - Mexico poultry trade

Since the inception of the North American Free Trade Agreement (NAFTA) in 1994, tariff restriction to U.S. poultry products entering the Mexican market has decreased significantly. While poultry trade from the U.S. to Mexico has increased considerably, Mexican chicken exports to the U.S. face a sanitary restriction. This concerns chicken producers in Mexico. Consequently, the Mexican government negotiated with the U.S. government an extension, from 2003 to 2008, of the tariff rate quota (TRQ) on U.S. chicken leg quarters entering the Mexican market. The purpose of this study was to estimate the economic impact of trade policies restricting the chicken trade between Mexico and the U.S. Two trade policy scenarios were analyzed: (1) a removal of the Mexican tariff rate quota (TRQ) on U.S. chicken leg quarters, and (2) a removal of the TRQ and, in addition, a removal of the U.S. sanitary restrictions to Mexican chicken. A cost minimization mathematical programming model was used to estimate the optimum levels of production, consumption and trade, subject to policy restrictions. The study found that if the Mexican TRQ on U.S. chicken leg quarters is eliminated, chicken production in Mexico would shrink by 51% compared to the actual level of production as of 2003. A less drastic effect on Mexican production of chicken was found when, in addition to the TRQ removal, the U.S. sanitary restriction on Mexican chicken is eliminated. In this second scenario total production in Mexico would decrease by 24%. Under both scenarios chicken production in the U.S. is estimated to have an increase, 8% and 4% for the first and second scenarios, respectively. These new levels of production would affect trade levels and prices for chicken and chicken parts in both countries

Essays on Price Dynamics, Welfare Analysis, Household Food Insecurity in Mexico

Higher and more volatile food prices, as reported in recent years, have consequences on household welfare and potentially on public policy. Analysis of agricultural commodities price dynamics, welfare effects of increased food prices, and determinants of household food insecurity are discussed and presented in three separate essays. In the first essay, the dynamic information flows among prices of important agricultural commodities in the United States (U.S.) and Mexico for the years 2000-2012 are analyzed. Error correction models and directed acyclical graphs are employed with observational data to identify the dynamic relationships among prices of grains and meats. Unlike previous studies, results here suggest the existence of long-run relationships among prices in both countries. U.S. grain prices have a consistently strong impact on price movements in Mexican agricultural markets in the long-run. In the second essay, the impacts of rising food prices on poverty and welfare of Mexican households are examined by using a linearized version of the Exact Affine Stone Index (EASI) demand system. The distribution of monetary measures of welfare effects from food price changes is estimated as well as equivalence scales that allow inter-household comparison of welfare changes. After accounting for substitution effects, poverty related impacts are estimated. Findings indicate that the actual increase in prices of five food groups from 2006 to 2010 led to an increase of 1.8 percentage points in the proportion of households with income below the food poverty line. The third essay uses an ordered probit model with a nationally representative dataset and a newly developed food security scale in Mexico to identify the demographic determinants of household food insecurity. The analysis is conducted for the general population first and then for a subpopulation group of rural lower-income households. It was found that households with younger, less-educated household heads were more likely to suffer from food insecurity. Other groups that were found to be vulnerable in terms of food insecurity include: households headed by a single, widowed or divorced mother, households with disabled family members, households with strong indigenous background, rural households, low-income households, non-agricultural households, and households with children

Wikidata: Open Linked Data for Library Publishing

Presentation given at the 2019 Library Publishing ForumWikidata, a collaboratively edited, open, linked data knowledge base hosted by the Wikimedia foundation, includes a growing collection of open citation data. As of November 2018, more than 20 million publications and 160 million citations have been contributed to Wikidata (http://wikicite.org/statistics.html). Many of these data items have been added by bots that contribute data from open bibliographic databases, including PubMed Central, and from data made available by Crossref and the Initiative for Open Citations (I4OC). Although this approach may be the most efficient way to build a large corpus of open citation data, many scholarly journals will be missed. Journals that cannot meet the requirements of a Crossref contract (for financial or technical reasons) will be invisible in growing open citation network. The journals that are likely to be missed are also those that have not been well-served by for-profit publishers and large university presses–including print journals that flipped to open access and journals in fields that are unfamiliar with or unconvinced of the value of a Crossref DOI (e.g., law reviews and some arts and humanities journals). In this presentation we demonstrate how a library publisher can contribute bibliographic data to Wikidata. By using both manual and batch-processing methods, we contributed complete runs for selected journals hosted on our library’s instance of Open Journal Systems. We share our methods for contributing data for journals that mint DOIs and for journals that do not. We also provide a demonstration of the short-term benefits of building this collection in Wikidata and reflect on the challenges of including Wikidata in a library-publishing program

Efectos de la acción sísmica, en edificaciones regulares de concreto armado considerando la interacción suelo-estructura de manera explícita para suelos arenosos y arcillosos

Realiza una comparación y análisis de varianza entre los resultados obtenidos haciendo uso de la metodología tradicional con la metodología explícita simplificada que incorpora los efectos de interacción suelo-estructura, a través de la modificación del apoyo de la edificación de rígido a flexible, con el uso de resortes cuyas rigideces se calibraron a partir de funciones de impedancia dinámica, en donde se concluyó que la metodología recomendada por la normativa venezolana puede llegar a ser más conservadora que la utilizada en esta investigación. Puesto que no considera la rigidez del sistema suelo fundación de manera flexible, despreciando la capacidad de deformación del suelo. Esto se puede ver reflejado en los resultados obtenidos como de la aplicación de dicha metodología explícita simplificada, ya que los mismos arrojaron valores de menores de cortante basal y momento de volcamiento que los obtenidos por el análisis tradicional. Por lo tanto, se recomienda que al incorporar los efectos de interacción suelo-estructura en el análisis estructural, se tome en cuenta la rigidez del sistema suelo fundación, ya que implementarlo ayuda a obtener respuestas más reales del análisis sísmico estructural, disminuyendo parte de las incertidumbres de diseño y por lo tanto la vulnerabilidad en las edificaciones.Trabajo de suficiencia profesiona

Características epidemiologícas (clínicas, radiológicas y microbiológicas) de la enfermedad periodontal, en empleados municipales de 22 a 45 años de edad de la República de Guatemala, año 2008

Con el propósito de establecer la prevalencia, severidad, extensión, características radiológicas de la enfermedad periodontal, así como la presencia de Actinobacillus actinomycetemcomitans (A.a.) y Porphyromonas gingivalis (P.g.) en empleados municipales de 22 a 45 años de la República de Guatemala en el año 2009, se seleccionó una muestra aleatoria por conglomerados, en dos etapas, de todas las municipalidades del país; se incluyeron las 8 regiones contempladas por el Ministerio de Salud Pública y Asistencia Social, de las cuales se tomó 3 Municipalidades por región y 13 personas por institución, para un total de 39 personas por región y 312 por toda la República. Se incluyó únicamente a las personas que aceptaron participar mediante un consentimiento informado y comprendido. A cada paciente se le realizo una anamnesis, un examen de la cavidad bucal y un examen periodontal que incluyó: dientes presentes, sondeo periodontal (PSG), determinación de sangrado al sondeo (SS), presencia de factores irritantes y movilidad dental; 6 exposiciones radiográficas y toma de muestras de placa dentobacteriana (PDB) de las 4 áreas gingivales con mayor profundidad y de las mucosas de carrillo, lengua y región amigdalina. El 99.68% de los sujetos examinados presentó enfermedad periodontal. El 36.86% de los sujetos presentó 4mm, SS, irritantes, furcas o movilidad. El 100% de los sujetos estudiados presentó PDB; el 91.66% presentó cálculos. El 51.3% de los pacientes presentó pérdida de la continuidad de la lámina dura, el 57.7% presentó reabsorción de la cresta ósea y el 13.1% presentó ensanchamiento del ligamento periodontal. El 2.05% de los pacientes presentó la bacteria (A.a). se concluye que la prevalencia de la enfermedad periodontal es alta, la severidad es leve, la extensión es localizada. El examen radiológico evidenció pérdida ósea. La presencia de (A.a.) fue baja

La tabla de eclipses en el códice de Dresden. Más de cien años de estudio y discusión

El códice Dresden es el más antiguo de tres libros escritos con glifos mayas que han sobrevivido hasta nuestros días. Contiene tablas y almanaques relacionados a los planetas visibles y una tabla con 69 intervalos de 177 o 148 días relacionados a eclipses de sol y de luna que a pesar de haber sido estudiada por más de 100 años, sigue motivando ideas y propuestas sobre su posible uso y significado. La opinión más aceptada es que la tabla es uninstrumento para predecir la posibilidad de eclipses, sin embargo algunos investigadores piensan que puede ser un registro de eclipses observados si se cambia la correlación entre los calendarios maya y gregoriano, lo cual ha llevado a proponer otras correlaciones entre calendarios. Algunos artículos proponen que la tabla se refiere a eclipses de sol, otros a eclipses de luna, o incluso de ambos tipos. El objetivo del presente estudio es comparar losdatos en la tabla de eclipses con el catálogo de eclipses ocurridos del año cero al año 1500 de esta era y presentar bajo un mismo instrumento las evidencias a favor de las varias hipótesis en la literatura científica sobre el tema, considerando solamente la información en las tablas numéricas. Aunque dejar de lado la información en los textos jeroglíficos e imágenes limita el alcance de las conclusiones, la intención es proporcionar una visión imparcial de los datos en la tabla que permita estimar la validez de los distintos argumentos propuestos en la literatura, como un primer paso para desarrollar instrumentos que sirvan para un estudio multidisciplinario enfocado en estudiar las diez figuras que sobresalen en la tabla, las cuales son tan elaboradas y contienen tanto detalle que es muy probable que correspondan a fenómenos que sí fueron observados por los antiguos astrónomos

Comparación de métodos de caracterización de señales MER

En este documento presenta una comparación de los métodos propuestos para la caracterización de señales provenientes de microeléctrodos de registro (MER) para la identificación de zonas cerebrales que intervienen en la cirugía de la enfermedad de Parkinson. Los mejores porcentajes de acierto se obtienen utilizando como método de caracterización la transformada wavelet, 97.37% y 71.4% para 2 y 4 clases respectivamente.This document presents a microelectrode registers feature extraction methodologies comparison for brain zones identification found in Parkinson¿s disease surgery. Best results are obtained using wavelet transforms, 97.37% and 71.4% for 2 and 4 classes, respectively