545 research outputs found

    The Effect of Market Structure on Pest Resistance Buildup

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    In this paper we present a continuous time optimal control analysis of resistance buildup in agricultural chemicals when the supplier is a monopolist. We compare the monopolistic, competitive and socially optimal solutions after establishing the stability of each equilibrium. The central finding is that with a monopolistic supplier, resistance buildup is lower than socially optimal. This directly opposes the standard result in the resistance literature. This implies that policies to manage resistance should vary with the age of the chemical, with no intervention during the lifetime of a patent and an optimal tax once the patent expires.Research Methods/ Statistical Methods,

    Payments for Environmental Services: To whom, where, and how much?

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    In this paper we consider different strategies for implementing a payment for environmental services (PES) program to mitigate deforestation in Mexican common property forests (ejidos). We begin by discussing the policy context within which PES programs find themselves, highlighting other possible interventions to help preserve environmental amenities in Mexico. We then discuss some basic principles of environmental payment schemes, formalizing these into three that we simulate: payment of the opportunity cost for forests at risks; payment for environmental benefits provided by forests at risk; a flat payment scheme with a cap on allowable hectares, similar to the type of program often applied in developing countries; and a program of opportunity cost payments for forest at risk with highest environmental benefit per dollar paid. We find that, of these three, the last is most efficient and the second most egalitarian. We also repeat a simulation of the third scheme using predicted, rather than actual risk, which circumvents the problem of strategic behavior on the part of recipient communities but introduces some error into the targeting process. Finally, we consider the characteristics of communities that receive payments from the most efficient program, finding that larger and more remote ejidos receive the lion's share of the budget, but that payments to them are not necessarily more efficient. This scheme also gives more, though smaller on a per capita basis, payments to poor and indigenous communities, where they are more efficient than those to non-poor and non-indigenous ejidos.Environmental Economics and Policy,

    A new Eliomys from the Upper Miocene of Spain and its implications for the phylogeny of genus

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    In this paper, we describe a previously unknown species of the glirid Eliomys from the Late Miocene and Early Pliocene Cabriel, Alcoy and Granada basins of southeastern Spain. Eliomys yevesi sp. nov. is characterized by its relative small size, narrow lingual wall and common presence of two centrolophs in the upper molars, and well-developed centrolophids in the lower molars. The new species is the probable ancestor of E. intermedius, which in turn represents the ancestor of the extant E. quercinus. According to its morphologic and biometric features, the origin of E. yevesi sp. nov. is likely to be found in some population of E. truci from the Late Miocene. Based on these affinities, we propose the lineage E. truci–E. yevesi sp. nov.–E. intermedius–E. quercinus, in which there is a trend towards the development of centrolophs, as well as the reduction of accessory crests

    Centennial-scale vegetation and North Atlantic Oscillation changes during the Late Holocene in the southern Iberia

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    High-reso CE to lution pollen analysis, charcoal, non-pollen palynomorphs and magnetic susceptibility have been analyzed in the sediment record of a peat bog in Sierra Nevada in southern Iberia. The study of these proxies provided the reconstruction of vegetation, climate, fire and human activity of the last ∼4500 cal yr BP. A progressive trend towards aridification during the late Holocene is observed in this record. This trend is interrupted by millennial- and centennial-scale variability of relatively more humid and arid periods. Arid conditions are recorded between ∼4000 and 3100 cal yr BP, being characterized by a decline in arboreal pollen and with a spike in magnetic susceptibility. This is followed by a relatively humid period from ∼3100 to 1600 cal yr BP, coinciding partially with the Iberian-Roman Humid Period, and is indicated by the increase of Pinus and the decrease in xerophytic taxa. The last 1500 cal yr BP are characterized by several centennial-scale climatic oscillations. Generally arid conditions from ∼450 to 1300 CE, depicted by a decrease in Pinus and an increase in Artemisia, comprise the Dark Ages and the Medieval Climate Anomaly. Since ∼ 1300 to 1850 CE pronounced oscillations occur between relatively humid and arid conditions. Four periods depicted by relatively higher Pinus coinciding with the beginning and end of the Little Ice Age are interrupted by three arid events characterized by an increase in Artemisia. These alternating arid and humid shifts could be explained by centennial-scale changes in the North Atlantic Oscillation and solar activity

    Recopilación de la costumbre mercantil en las panaderías del municipio de Pamplona, que han manejado el vendaje como estrategia promocional y comercial dentro del ambiente de mercadeo

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    El mercadeo es una actividad cuya finalidad consiste en satisfacer las necesidades y deseos del ser humano mediante el proceso de intercambio, buscando asegurar el logro de los objetivos de la empresa. Para ello se requiere analizar el macroentorno, ya que tiene seis componentes que interactúan en forma compleja y que son críticos desde el punto de vista de mercadeo: el político y legal, el económico, el competitivo, el tecnológico, el sociocultural y el demográfico. Además la organización debe estar centrada en satisfacer las necesidades del consumidor o usuario, porque de ellos depende la permanencia en el mercado; es una labor difícil debido a que estamos en una sociedad muy cambiante y cada consumidor tiene su propio estilo de vida influyendo en las decisiones de compra. No se puede dejar de lado la consideración que hace la Corte Constitucional con respecto a la libre competencia económica, si bien es un derecho de todos, por precepto constitucional, supone ciertas responsabilidades, razón por la cual la ley puede delimitar el alcance de la libertad económica, cuando así lo exija el interés social. Las panaderías de Pamplona se han caracterizado por ser un mercado conservador y de gran tradición, además ha ido experimentado un crecimiento, es por ello que la Cámara de Comercio de Pamplona decidió orientar su labor de recopilación de la costumbre mercantil hacia este sector y confiamos que el trabajo que se adelantó, además de satisfacer los objetivos de orden legal, contribuyan en alguna medida a la promoción del desarrollo regional mediante el análisis del ambiente del mercadeo y sea la base de posteriores estudios en este sector comercial, que en últimas es nuestra gran misión como estudiantes de la UNAD.El mercadeo es una actividad cuya finalidad consiste en satisfacer las necesidades y deseos del ser humano mediante el proceso de intercambio, buscando asegurar el logro de los objetivos de la empresa. Para ello se requiere analizar el macroentorno, ya que tiene seis componentes que interactúan en forma compleja y que son críticos desde el punto de vista de mercadeo: el político y legal, el económico, el competitivo, el tecnológico, el sociocultural y el demográfico. Además la organización debe estar centrada en satisfacer las necesidades del consumidor o usuario, porque de ellos depende la permanencia en el mercado; es una labor difícil debido a que estamos en una sociedad muy cambiante y cada consumidor tiene su propio estilo de vida influyendo en las decisiones de compra. No se puede dejar de lado la consideración que hace la Corte Constitucional con respecto a la libre competencia económica, si bien es un derecho de todos, por precepto constitucional, supone ciertas responsabilidades, razón por la cual la ley puede delimitar el alcance de la libertad económica, cuando así lo exija el interés social. Las panaderías de Pamplona se han caracterizado por ser un mercado conservador y de gran tradición, además ha ido experimentado un crecimiento, es por ello que la Cámara de Comercio de Pamplona decidió orientar su labor de recopilación de la costumbre mercantil hacia este sector y confiamos que el trabajo que se adelantó, además de satisfacer los objetivos de orden legal, contribuyan en alguna medida a la promoción del desarrollo regional mediante el análisis del ambiente del mercadeo y sea la base de posteriores estudios en este sector comercial, que en últimas es nuestra gran misión como estudiantes de la UNAD

    Early identification of brain injury in infants with hypoxic ischemic encephalopathy at high risk for severe impairments: accuracy of MRI performed in the first days of life

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    BACKGROUND: Despite therapeutic hypothermia 30-70% of newborns with moderate or severe hypoxic ischemic encephalopathy will die or survive with significant long-term impairments. Magnetic resonance imaging (MRI) in the first days of life is being used for early identification of these infants and end of life decisions are relying more and more on it. The purpose of this study was to evaluate how MRI performed around day 4 of life correlates with the ones obtained in the second week of life in infants with hypoxic-ischemic encephalopathy (HIE) treated with hypothermia. METHODS: Prospective observational cohort study between April 2009 and July 2011. Consecutive newborns with HIE evaluated for therapeutic hypothermia were included. Two sequential MR studies were performed: an •early’ study around the 4th day of life and a •late’ study during the second week of life. MRI were assessed and scored by two neuroradiologists who were blinded to the clinical condition of the infants. RESULTS: Forty-eight MRI scans were obtained in the 40 newborns. Fifteen infants underwent two sequential MR scans. The localization, extension and severity of hypoxic-ischemic injury in early and late scans were highly correlated. Hypoxic-ischemic injury scores from conventional sequences (T1/T2) in the early MRI correlated with the scores of the late MRI (Spearman ρ = 0.940; p < .001) as did the scores between diffusion-weighted images in early scans and conventional images in late MR studies (Spearman ρ = 0.866; p < .001). There were no significant differences in MR images between the two sequential scans. CONCLUSIONS: MRI in the first days of life may be a useful prognostic tool for clinicians and can help parents and neonatologist in medical decisions, as it highly depicts hypoxic-ischemic brain injury seen in scans performed around the second week of life

    Holocene geochemical footprint from Semiarid alpine wetlands in southern Spain

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    Here we provide the geochemical dataset that our research group has collected after 10 years of investigation in the Sierra Nevada National Park in southern Spain. These data come from Holocene sedimentary records from four alpine sites (ranging from ∼2500 to ∼3000 masl): two peatlands and two shallow lakes. Different kinds of organic and inorganic analyses have been conducted. The organic matter in the bulk sediment was characterised using elemental measurements and isotope-ratio mass spectrometry (EA-IRMS). Leaf waxes in the sediment were investigated by means of chromatography with flame-ionization detection and mass spectrometry (GC-FID, GC-MS). Major, minor and trace elements of the sediments were analysed with atomic absorption (AAS), inductively coupled plasma mass spectrometry (ICP-MS), as well as X-ray scanning fluorescence. These data can be reused by environmental researchers and soil and land managers of the Sierra Nevada National Park and similar regions to identify the effect of natural climate change, overprinted by human impact, as well as to project new management policies in similar protected areas.Universidad de Granada. Departamento de Estratigrafía y PaleontologíaJunta de Andalucía: Grupos de investigación RNM190 y RNM309Junta de Andalucía: Proyecto P11-RNM-7332España, Ministerio de Economía y Competitividad: Proyecto CGL2013-47038-RRamón y Cajal Fellowship: RYC-2015-18966Small Research Grant by the Carnegie Trust for the Universities of ScotlandMarie Curie Intra-European Fellowship of the 7th Framework Programme for Research, Technological Development and Demonstration of the European Commission: NAOSIPUK. Grant Number: PIEF-GA-2012-62302

    Ten years since the introduction of therapeutic hypothermia in neonates with perinatal hypoxic-ischaemic encephalopathy in Spain

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    More than a decade has passed since therapeutic hypothermia (TH) was introduced in Spain; this is the only neuroprotective intervention that has become standard practice in the treatment of perinatal hypoxic-ischaemic encephalopathy (HIE). This article aims to provide a current picture of the technique and to address the controversies surrounding its use. In the last 10 years, TH has been successfully implemented in the vast majority of tertiary hospitals in Spain, and more than 85% of newborns with moderate or severe HIE currently receive the treatment. The factors that can improve the efficacy of TH include early treatment onset (first 6 hours of life) and the control of comorbid factors associated with perinatal asphyxia. In patients with moderate HIE, treatment onset after 6 hours seems to have some neuroprotective efficacy. TH duration longer than 72 hours or deeper hypothermia do not offer greater neuroprotective efficacy, but instead increase the risk of adverse effects. Unclarified aspects are the sedation of patients during TH, the application of the treatment in infants with mild HIE, and its application in other scenarios. Prognostic information and time frame are one of the most challenging aspects. TH is universal in countries with sufficient economic resources, although certain unresolved controversies remain. While the treatment is widespread in Spain, there is a need for cooling devices for the transfer of these patients and their centralisationSe cumple ahora más de una década del inicio de la hipotermia terapéutica (HT) en España, la única intervención neuroprotectora que ha venido a ser práctica estándar en el tratamiento de la encefalopatía hipóxico-isquémica perinatal (EHI). El objetivo de este artículo es ofrecer un panorama actual y presentar las controversias surgidas alrededor de la aplicación de esta terapia. En esta década se ha implantado con éxito la HT en la gran mayoría de los hospitales terciarios de España y más del 85% de los recién nacidos con EHI moderada-grave reciben esta terapia. Entre los aspectos que pueden mejorar la eficacia de la HT están su inicio precoz dentro de las primeras 6 horas de vida y el control de factores comórbidos asociados a la asfixia perinatal. En los pacientes con EHI moderada el inicio después de las 6 horas parece mantener cierta eficacia neuroprotectora. Una duración de la HT mayor de 72 horas o un enfriamiento más profundo no ofrecen mayor eficacia neuroprotectora y aumentan el riesgo de efectos adversos. Persiste la controversia acerca de la sedación durante la HT, la aplicación de esta intervención a los neonatos con EHI leve y en otros escenarios. La información pronóstica y su marco temporal es uno de los aspectos más desafiantes. La HT es universal en países con recursos económicos, aunque existen puntos de controversia no resueltos. Si bien es un tratamiento generalizado en nuestro país, falta disponer de dispositivos para el traslado de estos pacientes y su centralizació
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