691 research outputs found

    iTETRIS Platform Architecture for the Integration of Cooperative Traffic and Wireless Simulations

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    The use of cooperative wireless communications can support driving through dynamic exchange of Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) messages. Traffic applications based on such systems will be able to generate a safer, faster, cheaper and cleaner way for people and goods to move. In this context, the iTERIS project aims at providing the framework to combine traffic mobility and wireless communication simulations for large scale testing of traffic management solutions based on cooperative systems. This paper addresses the description and explanation of the implementation choices taken to build a modular and interoperable architecture integrating heterogeneous traffic and wireless simulators, and application algorithms supporting traffic management strategies. The functions of an “in-between” control system for managing correct simulation executions over the platform are presented. The inter-block interaction procedures identified to ensure optimum data transfer for simulation efficiency are also introduced

    Agricultural support policies and GHG emissions from agriculture in Latin America: relationships and policy implications for climate change

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    Domestic support policies for farmers and agriculture, through their price effect, have been deemed potentially environmentally harmful; for example, in developing countries, agricultural prices have been set- below the world market prices, aiming to secure low retail prices for urban consumers. This practice has lowered producer prices, and thereby prevented farmers from adopting ecofriendly production techniques. This study uses policy data —market price support (MPS) and general service support estimates (GSSE) as shares of total support estimate (TSE)— and greenhouse gases (GHG) data for main crops and livestock sectors in 18 Latin-American countries and it applies cluster analysis to construct a typology that highlights patterns between policy incentives for agricultural crops and activities and GHG emissions. The results suggest that an increase in the TSE and/or MPS comprising a large share of the TSE leads to an increase in GHGs. Conversely, GHGs fall when GSSE comprise a larger share of the TSE. Las políticas internas de apoyo a los agricultores y la agricultura, a través de su efecto sobre los precios, pueden ser potencialmente dañinas para el medio ambiente; por ejemplo, en los países en desarrollo, los precios agrícolas se han fijado por debajo de los precios del mercado mundial, con el objetivo de asegurar precios minoristas bajos para los consumidores urbanos. Esta práctica reduce bajar los precios al productor y, por lo tanto, es un obstáculo que los agricultores adopten técnicas de producción ecológicas. En este estudio, se utilizan datos de políticas —soporte de precios de mercado y estimaciones de apoyo a los servicios generales como porcentajes de la estimación del apoyo total— y datos de gases de efecto invernadero (GEI) para los principales cultivos y sectores ganaderos en 18 países latinoamericanos, además de aplicarse análisis de conglomerados para construir una tipología en la que se destacan patrones entre políticas de incentivos para cultivos y actividades agrícolas y emisiones de GEI. Los resultados sugieren que un aumento en la estimación del apoyo total y/o en el soporte de precios de mercado, que comprende una gran parte, conduce a un incremento en los GEI. Por el contrario, estos caen cuando las estimaciones de apoyo a los servicios generales comprenden una mayor parte de la estimación del apoyo total.

    Investigating the Efficiency of ITS Cooperative Systems for a Better Use of Urban Transport Infrastructures: The iTETRIS Simulation Platform

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    The use of cooperative ITS communication systems, supporting driving through the dynamic exchange of Vehicle-to- Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) messages, is a potential candidate to improve the economical and societal welfare. The application of such systems for novel cooperative traffic management strategies can introduce a lot of beneficial effects not only for road safety, but also for the economy related to transportation systems and the environmental impact. Despite this apparent set of promising features, City Road Authorities, which hold a key-role in determining the final adoption of such systems, still look at cooperative systems without sharing a clear opinion. This is mainly due to the current lack of definitive and solid evidences of the effectiveness of such systems when applied in the real world. In order to fill this gap and let Road Authorities estimate the usefulness of such technologies in achieving the objectives dictated by cities’ traffic management policies, the EU consortium iTETRIS is developing a simulation platform for large scale testing of traffic management solutions making use of cooperative ITS systems. Thanks to its own distinguishing features, iTETRIS aims at becoming a good supporting tool for Road Authorities to implement preliminary tests on the effectiveness of ITS solutions prior to investing money for the physical deployment of the communication infrastructures allowing their functioning

    Un'analisi geografica del disequilibrio di genere in India

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    India population has fewer women than men (the 2001 census recorded 93 women for every 100 men) and the number of "missing women" is estimated to be between 30 and 62 million. The volume explains this demographic gender imbalance by means of a geographical analysis that embraces social, cultural, religious and economic aspects. The convergence point of the variables that negatively influence the female sex ratio is the low social and cultural value enjoyed by women, which translates into such a discrimination (in the access to food resources, medical care, education and well-being) that it strongly affects the female mortality rate

    Voltage gated inter-cation selective ion channels from graphene nanopores

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    With the ability to selectively control ionic flux, biological protein ion channels perform a fundamental role in many physiological processes. For practical applications that require the functionality of a biological ion channel, graphene provides a promising solid-state alternative, due to its atomic thinness and mechanical strength. Here, we demonstrate that nanopores introduced into graphene membranes, as large as 50 nm in diameter, exhibit inter-cation selectivity with a ~20x preference for K+ over divalent cations and can be modulated by an applied gate voltage. Liquid atomic force microscopy of the graphene devices reveals surface nanobubbles near the pore to be responsible for the observed selective behavior. Molecular dynamics simulations indicate that translocation of ions across the pore likely occurs via a thin water layer at the edge of the pore and the nanobubble. Our results demonstrate a significant improvement in the inter-cation selectivity displayed by a solid-state nanopore device and by utilizing the pores in a de-wetted state, offers an approach to fabricating selective graphene membranes that does not rely on the fabrication of sub-nm pores

    Developmental switch from prolonged insulin action to increased insulin sensitivity in protein tyrosine phosphatase 1B-deficient hepatocytes

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    15 pages, 10 figures.Protein tyrosine phosphatase 1B (PTP1B) is a negative regulator of insulin signaling and a therapeutic target for type 2 diabetes. The purpose of this study was to evaluate the differences in insulin sensitivity between neonate and adult hepatocytes lacking PTP1B. Immortalized neonatal hepatocytes and primary neonatal and adult hepatocytes have been generated from PTP1B(-/-) and wild-type mice. PTP1B deficiency in immortalized neonatal hepatocytes prolonged insulin-induced tyrosine phosphorylation of the insulin receptor (IR) and IR substrates (IRS) -1, -2 compared with wild-type control cells. Endogenous IR and IRS-2 were down-regulated, whereas IRS-1 was up-regulated in PTP1B(-/-) neonatal hepatocytes and livers of PTP1B(-/-) neonates. Insulin-induced activation of phosphatidylinositol 3-kinase/Akt pathway was prolonged in PTP1B(-/-) immortalized neonatal hepatocytes. However, insulin sensitivity was comparable to wild-type hepatocytes. Rescue of PTP1B in deficient cells suppressed the prolonged insulin signaling, whereas RNA interference in wild-type cells promoted prolonged signaling. In primary neonatal PTP1B(-/-) hepatocytes, insulin prolonged the inhibition of gluconeogenic mRNAs, but the sensitivity to this inhibition was similar to wild-type cells. By contrast, in adult PTP1B-deficient livers, p85alpha was down-regulated compared with the wild type. Moreover, primary hepatocytes from adult PTP1B(-/-) mice displayed enhanced Akt phosphorylation and a more pronounced inhibition of gluconeogenic mRNAs than wild-type cells. Hepatic insulin sensitivity due to PTP1B deficiency is acquired through postnatal development. Thus, changes in IR and IRS-2 expression and in the balance between regulatory and catalytic subunits of phosphatidylinositol 3-kinase are necessary to achieve insulin sensitization in adult PTP1B(-/-) hepatocytes.This work was supported by Grant BFU 2005-01615 (to A.M.V.) and Grant SAF 2004-5545 (to M.B.) from Ministerio de Educación y Ciencia (Spain), Grant CAM/GR/SAL/0384/2004 (to A.M.V.) from Comunidad de Madrid (Spain), and Red de Grupos de Diabetes Mellitus Grant G03/212, Instituto Carlos III (Spain). A.G.-R. was supported by Grant FPU (Ministerio de Educación, Spain). O.E. was supported by Juan de la Cierva programe (Ministerio de Educación, Spain).Peer reviewe

    Un análisis exploratorio de los exchangeable trade funds y su influencia en el proceso de financiarización de commodities

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    The aim of this paper is to provide comprehensive insights into the architecture and impact of a recent financial innovation known as commodity index. The motivation of this study is based on the impact that these instruments may have in the functioning of commodity markets, leading to what the literature has called “financialization of commodities”. Therefore, we first present the concept of financialization. Then, we describe the architecture of commodites index and the corresponding trading vehicle called Exchangeable Trade Funds. In the third section we introduce an exploratory analysis of recent trends and stylized facts of the evolution of the market. We conclude with possible impacts of those instruments on the market, opening the hypothesis that they can generate a major source of risk in the markets that already describe a high level of volatility

    Symposium on basic writing, conflict and struggle, and the legacy of Mina Shaughnessy.

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    Two articles in the December 1992 College English presented historical perspectives on the field of Basic Writing. In Conflict and Struggle: The Enemies or Preconditions of Basic Writing? Min-Zhan Lu argued for the value of a pedagogy in which conflict and struggle help Basic Writers to reposition themselves; she suggested that resistance to such a pedagogy is traceable to three pioneers in the field, Kenneth Bruffee, Thomas Farrell, and Mina Shaughnessy, and the historical context in which they worked. In Waiting for an Aristotle, Paul Hunter analyzed the special issue of the Journal of Basic Writing published in 1980 as a memorial to Mina Shaughnessy, finding a conservative impulse both in its structure and in its reading of Shaughnessy\u27s message. This symposium presents several commentaries on Lu \u27s and Hunter\u27s articles, followed by the authors\u27 responses. Sources for all contributions to the Symposium are combined in a common Works Cited list at the end
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