111 research outputs found

    Adaptive refinement and selection process through defect localization for reconstructing an inhomogeneous refraction index

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    We consider the iterative reconstruction of both the internal geometry and the values of an inhomogeneous acoustic refraction index through a piecewise constant approximation. In this context, we propose two enhancements intended to reduce the number of parameters to reconstruct, while preserving accuracy. This is achieved through the use of geometrical informations obtained from a previously developed defect localization method. The first enhancement consists in a preliminary selection of relevant parameters, while the second one is an adaptive refinement to enhance precision with a low number of parameters. Each of them is numerically illustrated

    Genetic Dissection of Acute Ethanol Responsive Gene Networks in Prefrontal Cortex: Functional and Mechanistic Implications

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    Background Individual differences in initial sensitivity to ethanol are strongly related to the heritable risk of alcoholism in humans. To elucidate key molecular networks that modulate ethanol sensitivity we performed the first systems genetics analysis of ethanol-responsive gene expression in brain regions of the mesocorticolimbic reward circuit (prefrontal cortex, nucleus accumbens, and ventral midbrain) across a highly diverse family of 27 isogenic mouse strains (BXD panel) before and after treatment with ethanol. Results Acute ethanol altered the expression of ~2,750 genes in one or more regions and 400 transcripts were jointly modulated in all three. Ethanol-responsive gene networks were extracted with a powerful graph theoretical method that efficiently summarized ethanol\u27s effects. These networks correlated with acute behavioral responses to ethanol and other drugs of abuse. As predicted, networks were heavily populated by genes controlling synaptic transmission and neuroplasticity. Several of the most densely interconnected network hubs, including Kcnma1 and Gsk3β, are known to influence behavioral or physiological responses to ethanol, validating our overall approach. Other major hub genes like Grm3, Pten and Nrg3 represent novel targets of ethanol effects. Networks were under strong genetic control by variants that we mapped to a small number of chromosomal loci. Using a novel combination of genetic, bioinformatic and network-based approaches, we identified high priority cis-regulatory candidate genes, including Scn1b,Gria1, Sncb and Nell2. Conclusions The ethanol-responsive gene networks identified here represent a previously uncharacterized intermediate phenotype between DNA variation and ethanol sensitivity in mice. Networks involved in synaptic transmission were strongly regulated by ethanol and could contribute to behavioral plasticity seen with chronic ethanol. Our novel finding that hub genes and a small number of loci exert major influence over the ethanol response of gene networks could have important implications for future studies regarding the mechanisms and treatment of alcohol use disorders

    Intra-European Movement: Multi-Level or Mismatched Governance?

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    The case of intra-EU mobility raises significant debate about multi-level governance (MLG) both in analytical terms – how multi-level is governance of intra-EU mobility, what actors are involved and how? – and normative terms – can intra-EU mobility be seen as ‘successful’ multi-level governance? Intra-EU mobility is an area that faces both issue complexity and institutional complexity (Stephenson, 2013, pp. 817) and as such, the governance arrangements are often correspondingly complex. This chapter will attempt to locate the case of intra-EU mobility within the broader literature on multi-level governance and try to draw out lessons for understanding MLG as a practical, analytical and normative concept. This is relevant to both the understanding of intra-EU mobility and the understanding of MLG. On the one hand, additional cases help to support or refute the robustness of our conceptualisation of multi-level governance; on the other hand, MLG as a concept can help us to understand the entanglement of a complex issue that cuts across political and policy bounds. The chapter will first develop a framework of multi-level governance that can be applied to intra-EU migration. Then, the structural, relational and policy factors that affect MLG will be explored in the context of this specific case. The final section will try to craft some answers about what intra-EU migration policy can tell us about multi-level governance, and vice versa

    Approaches in biotechnological applications of natural polymers

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    Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

    Adenovirus humano tipo 36 (Ad36) se relaciona con un mejor perfil lipídico en niños mexicanos, pero no con obesidad.

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    Background. Obesity and its comorbidities are one of the main causes of death in Mexico; it is a multifactorial disease, in which the participation of an infectious agent has been evaluated. Ad36 is associated with obesity, but paradoxically also with lower levels of glucose, cholesterol and triglycerides; however, there is controversy in different populations. Objective. To evaluate the association of antibodies against Ad36 with anthropometric and biochemical variables. Material and Methods. Cross-sectional study in 299 Mexican-mestizo children of elementary schools (6-12 years old). Anthropometric measurements of height, body weight, waist circumference, thickness of the triceps skin fold were obtained; body mass index (BMI) and waist / height ratio were calculated. Biochemical variables included serum glucose, triglycerides, total cholesterol, high-density lipoproteins, and low-density lipoproteins. An enzyme-linked immunosorbent assay (ELISA) was used to determine antibodies against Ad36 in serum samples. Results. Anti-Ad36 antibodies were associated with lower levels of total serum cholesterol (β = -0.133, p = 0.021) and LDL (β = -0.166, p = 0.004), and with higher levels of HDL (β = 0.120, p = 0.037), but not with obesity. Conclusion. Previous exposure to Ad36 was associated with a better lipid profile in Mexican children, regardless of obesityIntroducción. La obesidad y su comorbilidad son de las principales causas de muerte en México, es una enfermedad multifactorial, en la que se ha visto además la participación de un agente infeccioso. Ad36 se ha asociado con obesidad, pero paradójicamente también con niveles más bajos de glucosa, colesterol y triglicéridos, sin embargo, existe controversia en diferentes poblaciones. Objetivo. Evaluar la asociación de anticuerpos antiAd36 con variables antropométricas y bioquímicas. Material y métodos. Estudio transversal en 299 niños mexicanos mestizos en edad escolar (6 a 12 años). Se obtuvieron mediciones antropométricas de altura, peso corporal, circunferencia de la cintura, grosor del pliegue cutáneo del tríceps, se calculó índice de masa corporal (IMC) y relación cintura/ altura. Las variables bioquímicas incluyeron niveles séricos de glucosa, triglicéridos, colesterol total, lipoproteínas de alta densidad y lipoproteínas de baja densidad. Se utilizó un ensayo inmunoabsorbente ligado a enzimas (ELISA) para determinar los anticuerpos contra Ad36 en las muestras de suero. Resultados. Los anticuerpos anti-Ad36 se asociaron con niveles más bajos de colesterol sérico total (β = -0.133, p = 0.021) y LDL (β = -0.166, p = 0.004), y con niveles más altos de HDL (β = 0.120, p = 0.037), pero no con obesidad. Conclusión. En resumen, la exposición previa a Ad36 se asoció con un mejor perfil lipídico en niños mexicanos, independientemente de la obesidad

    EVALUACIÓN DEL RIESGO SÍSMICO DEL FONDO HABITACIONAL DE LAS CIUDADES GUARENAS Y GUATIRE / SEISMIC RISK ASSESSMENT OF THE HOUSING BUILDINGS OF THE CITIES GUARENAS AND GUATIRE

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    Las ciudades Guarenas y Guatire constituyen la principal zona de expansión de población del área Metropolitana deCaracas y están expuestas a la posible ocurrencia de un sismo de moderada a gran intensidad, por ello evaluar la respuestasísmica estructural del fondo habitacional de estas ciudades ante estos constituye un objetivo de gran importancia para supoblación y autoridades. El resultado de este trabajo permitió, utilizando la información estructural existente, determinar lavulnerabilidad y estimar las pérdidas materiales de las tipologías constructivas existentes y estimar las pérdidas humanas,además de proponer medidas generales de reforzamiento estructural, para continuar de manera sostenible el desarrollourbanístico de estas ciudades. Entre sus resultados más notables se destacan que solo el 40% de la población de ambosmunicipios vive en edificaciones formales, más del 50% de estas edificaciones formales y el total de las edificaciones noformales de ambas ciudades se evalúan como de una vulnerabilidad alta. Toda esta información aparece cartografiada enun SIG para su uso por parte de las autoridades.ABSTRACTThe Guarenas and Guatire cities are the main development area of the metropolitan region of Caracas, and are exposedto the possible occurrence of an earthquake of moderate to high intensity. For this reason, the evaluation of the structuralseismic response of buildings housing in these cities plays an important role in the sustainable development. According tothe existing structural information, the result of this work allowed assessing the vulnerability and estimating the materiallosses of the existing building typologies as well as the human losses. Additionally, it proposes guidelines of structuralreinforcement, for the sustainable urban development in these cities. Among the most notable results are that only 40%of the population of both municipalities live in formal buildings, more than 50% of these formal buildings and the totalof the non-formal structures of both cities are evaluated as high vulnerable. All this information is mapped into a GIS foruse by the authorities.Keywords: Vulnerability, Seismic risk, Prioritization index, Structural damage, Causalities

    Global Invasion of <i>Lantana camara</i>: Has the Climatic Niche Been Conserved across Continents?

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    <div><p><i>Lantana camara</i>, a native plant from tropical America, is considered one of the most harmful invasive species worldwide. Several studies have identified potentially invasible areas under scenarios of global change, on the assumption that niche is conserved during the invasion process. Recent studies, however, suggest that many invasive plants do not conserve their niches. Using Principal Components Analyses (PCA), we tested the hypothesis of niche conservatism for <i>L. camara</i> by comparing its native niche in South America with its expressed niche in Africa, Australia and India. Using MaxEnt, the estimated niche for the native region was projected onto each invaded region to generate potential distributions there. Our results demonstrate that while <i>L. camara</i> occupied subsets of its original native niche in Africa and Australia, in India its niche shifted significantly. There, 34% of the occurrences were detected in warmer habitats nonexistent in its native range. The estimated niche for India was also projected onto Africa and Australia to identify other vulnerable areas predicted from the observed niche shift detected in India. As a result, new potentially invasible areas were identified in central Africa and southern Australia. Our findings do not support the hypothesis of niche conservatism for the invasion of <i>L. camara</i>. The mechanisms that allow this species to expand its niche need to be investigated in order to improve our capacity to predict long-term geographic changes in the face of global climatic changes.</p></div
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