Applications of analysis to the determination of the minimum number of distinct eigenvalues of a graph

We establish new bounds on the minimum number of distinct eigenvalues among real symmetric matrices with nonzero off-diagonal pattern described by the edges of a graph and apply these to determine the minimum number of distinct eigenvalues of several families of graphs and small graphs

La presencia de Boko Haram como factor de desestabilización político-social desde 2009 en Nigeria

O presente trabalho visa analisar a participação do grupo fundamentalista islâmico nigeriano, Boko Haram, principalmente na sociedade nigeriana, o qual constitui-se como um fator de desestabilização política e social desde a radicalização de suas ações em 2009. Embora o grupo tenha emergido oficialmente em 2002, e seus primeiros contatos com as redes da Al-Qaeda são conhecidos desde 2000, foi até 2009 que seus ataques se extremaram após a prisão e morte de centenas de seus membros. A partir daí, a violência armada desse grupo foi direcionada não só contra as forças de segurança nigerianas, mas também contra escolas, igrejas (cristãs ou muçulmanas) e contra aldeias e cidades inteiras, afetando também aos países da região e reforçando seu desejo de criar um Califado no norte do país.El presente trabajo tiene como objetivo analizar la participación del grupo fundamentalista islámico nigeriano, Boko Haram, principalmente en la sociedad nigeriana, el cual se constituye como un factor de desestabilización política y social desde la radicalización de sus acciones en 2009. Aunque el grupo surgió, oficialmente, en el año 2002, y se sabe de sus primeros contactos con las redes de Al- Qaeda desde el año 2000, fue hasta 2009 que se extremaron sus ataques tras la detención y muerte de centenares de sus integrantes, incluidos varios de sus líderes. A partir de entonces, la violencia armada de dicho grupo se dirigió no solo contra las fuerzas de seguridad nigerianas, sino también contra escuelas, iglesias (cristianas o musulmanas) y contra aldeas y ciudades enteras, afectando a los países de la región y reforzando su deseo de creación de un califato en el norte del país

Atomic Force Microscopy Imaging of Living Cells

Over the last two decades, Atomic Force Microscopy (AFM) has emerged as the tool of choice to image living organisms in a near-physiological environment. Whereas fluorescence microscopy techniques allow labeling and tracking of components inside cells and the observation of dynamic processes, AFM is mainly a surface technique that can be operated on a wide range of substrates including biological samples. AFM enables extraction of topographical, mechanical and chemical information from these sample

Relacion entre la personalidad y las preferencias por las tecnicas de ensenanza : evidencia de estudiantes de universidades tradicionales y privadas chilenas

105 p.Determinar la relación existente entre la personalidad de los estudiantes de las universidades chilenas y sus preferencias por las distintas metodologías de enseñanza utilizadas comúnmente en la asignatura de Marketing, ha sido el objetivo de estudio de esta investigación. La metodología utilizada establece la determinación de las variables de personalidad de los estudiantes universitarios muestreados, además de sus preferencias por los diferentes métodos de enseñanza, con objeto de, posteriormente, encontrar la dirección de relación entre estas variables. Para ello se aplicó el cuestionario "Percepciones de los estudiantes acerca de las técnicas de enseñanza" a 213 estudiantes universitarios chilenos, seleccionados de manera no probabilística, de la carrera de Ingeniería Comercial de las universidades: Diego Portales, de Chile, de Talca, del Desarrollo, Católica de Valparaíso, Católica de la Santísima Concepción y Central. Los resultados revelaron que las hipótesis de este estudio se cumplieron parcialmente, vale decir, sólo algunas variables de personalidad se relacionaron con los métodos instruccionales en la dirección predicha

Exploring the Readability of Ingredients Lists of Food Labels with Existing Metrics

Healthy diet and dietary behaviors are key components in prevention of chronic disease and management of chronic illness. Nutritional literacy has been associated with dietary behaviors and consumer choice of healthy foods. Nutritional literacy can be measured, for example, by examining consumer food label use, but current research focuses largely on the Nutrition Facts panel of a food product. Ingredients lists are critical for communicating food composition but are relatively unstudied in existing literature. The goal of this work is to measure the readability of ingredients lists on branded food products in the United States using existing metrics. We examined ingredients lists for all 495,646 products listed in the USDA Food Data Central database using four existing readability measures for text written in natural language. Each of these indices approximates the grade level that would be expected to comprehend a text; comparatively, patient consent forms are considered acceptable at an 8th grade reading level or lower. We report a broad variability for in readability using different metrics: ingredients lists recorded at a 9th grade reading level or higher to comprehend are found at rates of 16.5% (Automated Reading Index) to 74.9% (Gunning-Fog Index). Ingredients lists recorded at a 10th grade reading level or higher to comprehend are found at rates of 84.2% (using FRE Index). These results demonstrate the need to further explore how ingredients lists can be measured for readability, both for the purposes of consumer understanding as well as for supporting future nutrition research involving text mining

Population-based Interventions Engaging Communities of Color in Healthy Eating and Active Living: A Review

INTRODUCTION: The U.S. obesity epidemic is escalating, particularly among communities of color. Obesity control efforts have shifted away from individual-level approaches toward population-based approaches that address socio-cultural, political, economic, and physical environmental factors. Few data exist for ethnic minority groups. This article reviews studies of population-based interventions targeting communities of color or including sufficient samples to permit ethnic-specific analyses. METHODS: Inclusion criteria were established, an electronic database search conducted, and non-electronically catalogued studies retrieved. Findings were aggregated for earlier (early 1970s to early 1990s) and later (mid-1990s to present) interventions. RESULTS: The search yielded 23 ethnically inclusive intervention studies published between January 1970 and May 2003. Several characteristics of inclusive interventions were consistent with characteristics of community-level interventions among predominantly white European-American samples: use of non-interpersonal channels for information dissemination directed at broad spheres of influence (e.g., mass media), promotion of physical activity, and incorporation of social marketing principles. Ethnically inclusive studies, however, also placed greater emphasis on involving communities and building coalitions from study inception; targeting captive audiences; mobilizing social networks; and tailoring culturally specific messages and messengers. Inclusive studies also focused more on community than individual norms. Later studies used "upstream" approaches more than earlier studies. Fewer than half of the inclusive studies presented outcome evaluation data. Statistically significant effects were few and modest, but several studies demonstrated better outcomes among ethnic minority than white participants sampled. CONCLUSION: The best data available speak more about how to engage and retain people of color in these interventions than about how to create and sustain weight loss, regular engagement in physical activity, or improved diet. Advocacy should be directed at increasing the visibility and budget priority of interventions, particularly at the state and local levels

Blow up criterion for compressible nematic liquid crystal flows in dimension three

In this paper, we consider the short time strong solution to a simplified hydrodynamic flow modeling the compressible, nematic liquid crystal materials in dimension three. We establish a criterion for possible breakdown of such solutions at finite time in terms of the temporal integral of both the maximum norm of the deformation tensor of velocity gradient and the square of maximum norm of gradient of liquid crystal director field.Comment: 22 page

Mecanismos asociados a la resistencia al derribo “kdr” a la deltametrina en Aedes aegypti del occidente de Venezuela

moleculares involucrados con la resistencia al derribo “kdr” a la deltametrina en poblaciones de Aedes aegypti de los estados Trujillo, Lara y Táchira. Las poblaciones fueron expuestas a CK50 previamente determinadas mediante bioensayos con botellas impregnadas siguiendo la metodología de Brogdon (1989) por 1h. Posteriormente los insectos fueron colocados en envases post-recuperación libres de insecticidas y separados en 4 fenotipos: los no derribados luego de 1h, los recuperados a las 4h, los supervivientes y los muertos a las 24 horas post-exposición. Todos los ejemplares fueron seccionados; con cabeza y tórax se determinaron los niveles de esterasas α y β, oxidasas de función múltiple, glutation S transferasas y acetilcolinesterasa insensible y con el abdomen se extrajo ADN y se realizaron PCR para amplificar los alelos específicos Val1016 e Ile1016. Las enzimas desintoxicantes se incrementaron en la mayoría de las poblaciones entre las 4 y 24h posteriores a la exposición a la deltametrina sin encontrarse diferencia significativa con los niveles expresados en la cepa susceptible New Orleans (NO), excepto en la población de Ureña donde se encontró aumento significativo en las β-esterasas siendo superiores en el fenotipo superviviente con respecto al fenotipo muertos a las 24h. El genotipo silvestre V1016/V1016 prevaleció sobre el heterocigoto y homocigoto mutante en los cuatro fenotipos, en la mayoría de las poblaciones estudiadas, con excepción de la población Ureña donde el homocigoto mutante I1016/I1016 fue el genotipo predominante en los no derribados, lo cual se vio reflejado en la frecuencia alélica. Se asocia la mutación V1016I con la resistencia al derribo mostrada en las poblaciones evaluadas, destacando la importancia de la temprana detección de esta y otras mutaciones en el canal del sodio asociadas con resistencia a piretroides, lo cual debe ser considerado antes de incorporar el uso de deltametrina en el programa de control de Ae. aegypti en estas poblaciones

Deploying a Top-100 Supercomputer for Large Parallel Workloads: the Niagara Supercomputer

Niagara is currently the fastest supercomputer accessible to academics in Canada. It was deployed at the beginning of 2018 and has been serving the research community ever since. This homogeneous 60,000-core cluster, owned by the University of Toronto and operated by SciNet, was intended to enable large parallel jobs and has a measured performance of 3.02 petaflops, debuting at #53 in the June 2018 TOP500 list. It was designed to optimize throughput of a range of scientific codes running at scale, energy efficiency, and network and storage performance and capacity. It replaced two systems that SciNet operated for over 8 years, the Tightly Coupled System (TCS) and the General Purpose Cluster (GPC). In this paper we describe the transition process from these two systems, the procurement and deployment processes, as well as the unique features that make Niagara a one-of-a-kind machine in Canada.Comment: PEARC'19: "Practice and Experience in Advanced Research Computing", July 28-August 1, 2019, Chicago, IL, US