408 research outputs found

    Economies of scale and scope in publicly funded biomedical and health research: evidence from the literature

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    BACKGROUND: Publicly funded biomedical and health research is expected to achieve the best return possible for taxpayers and for society generally. It is therefore important to know whether such research is more productive if concentrated into a small number of ‘research groups’ or dispersed across many. METHODS: We undertook a systematic rapid evidence assessment focused on the research question: do economies of scale and scope exist in biomedical and health research? In other words, is that research more productive per unit of cost if more of it, or a wider variety of it, is done in one location? We reviewed English language literature without date restriction to the end of 2014. To help us to classify and understand that literature, we first undertook a review of econometric literature discussing models for analysing economies of scale and/or scope in research generally (not limited to biomedical and health research). RESULTS: We found a large and disparate literature. We reviewed 60 empirical studies of (dis-)economies of scale and/or scope in biomedical and health research, or in categories of research including or overlapping with biomedical and health research. This literature is varied in methods and findings. At the level of universities or research institutes, studies more often point to positive economies of scale than to diseconomies of scale or constant returns to scale in biomedical and health research. However, all three findings exist in the literature, along with inverse U-shaped relationships. At the level of individual research units, laboratories or projects, the numbers of studies are smaller and evidence is mixed. Concerning economies of scope, the literature more often suggests positive economies of scope than diseconomies, but the picture is again mixed. The effect of varying the scope of activities by a research group was less often reported than the effect of scale and the results were more mixed. CONCLUSIONS: The absence of predominant findings for or against the existence of economies of scale or scope implies a continuing need for case by case decisions when distributing research funding, rather than a general policy either to concentrate funding in a few centres or to disperse it across many

    Impulsiveness Mediates the Association between \u3ci\u3eGABRA2\u3c/i\u3e SNPs and Lifetime Alcohol Problems

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    Genetic variants in GABRA2 have previously been shown to be associated with alcohol measures, electroencephalography (EEG) β waves and impulsiveness-related traits. Impulsiveness is a behavioral risk factor for alcohol and other substance abuse. Here, we tested association between 11 variants in GABRA2 with NEO-impulsiveness and problem drinking. Our sample of 295 unrelated adult subjects was from a community of families with at least one male with DSM-IV alcohol use diagnosis, and from a socioeconomically comparable control group. Ten GABRA2 SNPs (single-nucleotide polymorphisms) were associated with the NEO-impulsiveness (P \u3c 0.03). The alleles associated with higher impulsiveness correspond to the minor alleles identified in previous alcohol dependence studies. All ten SNPs are in linkage disequilibrium (LD) with each other and represent one effect on impulsiveness. Four SNPs and the corresponding haplotype from intron 3 to intron 4 were also associated with Lifetime Alcohol Problems Score (LAPS, P \u3c 0.03) (not corrected for multiple testing). Impulsiveness partially mediates (22.6% average) this relation between GABRA2 and LAPS. Our results suggest that GABRA2 variation in the region between introns 3 and 4 is associated with impulsiveness and this effect partially influences the development of alcohol problems, but a direct effect of GABRA2 on problem drinking remains. A potential functional SNP rs279827, located next to a splice site, is located in the most significant region for both impulsiveness and LAPS. The high degree of LD among nine of these SNPs and the conditional analyses we have performed suggest that all variants represent one signal

    Electric-pulse-induced reversible resistance in doped zinc oxide thin films

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    Nonvolatile, electric-pulse-induced resistance switching is reported on S and Co doped ZnO thin films deposited on different substrates using magnetron sputtering and laser ablation. Two resistance states were obtained by applying voltage pulses of different polarity. The switching was observed regardless of the substrate, dopant species, or microstructure of the samples. In the Co doped ZnO samples, the two resistance states are remarkably stable and uniform

    Sistemas de terminação de cordeiros do grupo genético pantaneiro.

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    Resumo: Ovinos Pantaneiros são nativos do Bioma Pantanal, na região Centro Oeste do Brasil, que tem como característica a produção de carne. Normalmente são criados em pastagens, sendo os cordeiros terminados geralmente no confinamento. Porém deve-se considerar sistemas de terminação sustentáveis e intensivos, adaptados a região. Neste sentido foram avaliados quatro sistemas de terminação, incluindo o desempenho produtivo e a eficiência econômica e indicadores de rentabilidade. Foram utilizados 54 cordeiros, 24 machos e 30 fêmeas, desverminados no desmame, com peso inicial de 16,70 kg, com idade média de 74±9 dias. Os sistemas de terminação avaliados foram o confinamento a base de volumoso de silagem de milho (Zea mays) (M); confinamento a base de volumoso de silagem de milho mais guandú (Cajanus cajan cv Mandarim) (MG); Integração Lavoura Pecuária (ILP) pastejo em Brachiaria brizantha cv. BRS Piatã mais guandú (Cajanus cajan cv Mandarim) em sucessão ao cultivo consorciado; pasto vedado (V) com Brachiaria brizantha cv. BRS Piatã. Em todos tratamentos os animais receberam suplementação de concentrado energético-proteico (16% PB e 82% NDT) equivalente a 2% do peso vivo. O delineamento experimental utilizado foi o inteiramente casualizado em esquema fatorial, sendo 4 sistemas de terminação e 2 sexos. As variáveis avaliadas foram, peso final (PVF) e ganho de peso médio diário (GMD), e a projeção econômica. Os sistemas de terminação sob M e ILP, obtiveram melhores desempenhos produtivos, não diferindo significativamente do MG, que por sua vez não diferiu estatisticamente do V. No entanto, na avaliação econômica ficou demonstrado que os sistemas ILP e MG foram mais rentáveis na terminação de cordeiros. O sistema a pasto formado em Integração Lavoura-Pecuária, com suplementação correspondente a 2% do peso corporal, mostrou-se o mais indicado para a região Centro-Oeste na terminação de cordeiros Pantaneiros no período seco. [Finishing systems of lambs pantaneiro genetic group]. Abstract: Pantaneiro genetic sheep group are native to the Pantanal Biome, in the Midwest region of Brazil, which is characterized by the production of meat. They are usually created under pasture, and the lambs usually finished in confinement. But should be considered sustainable and intensive finishing systems, adapted to the region. The aim of this study was to evaluate four finishing systems, including the productive performance and economic results as profitability indicators. Were used 54 lambs, 24 males and 30 females, wormed at weaning, with initial weight of 16.70 kg, with a mean age of 74 ± 9 days. Finishing systems were; Feedlot with corn silage (Zea mays) (CS) as roughage; Feedlot with mix corn silage and Pigeon pea (Cajanus cajan cv Mandarin) as roughage (CPS); Integration Crop-Livestock (ICL) grazing Brachiaria brizantha cv. BRS Piatã grass with Pigeon pea (Cajanus cajan cv Mandarin) in succession to mixed cultivation; stockpiled pasture (SP) with Brachiaria brizantha cv. BRS Piatã grass. All treatments the animals received energy-protein concentrate supplementation (16% CP and 82% TDN) equivalent to 2% of body weight. The experimental design was completely randomized in a factorial design, with four finishing systems and two sexes. The variables were final weight (FW) and average daily gain (ADG), and economic evaluation. Finishing systems under CS and ICL, obtained better productive performance not differing significantly from the CPS, which in turn did not differ statistically from SP. However, the economic evaluation demonstrated that the ICL and CPS systems were more profitable in finishing lambs. The pasture system formed in Integration Crop-Livestock with supplement of 2% of body weight, proved to be the most appropriate for the Midwest region in the finishing of Pantaneiro lambs in the dry season.Dissertação (Mestrado em Zootecnia) - Universidade Federal de Goiás, Goiânia. Orientador: João Restle; Coorientador: José Alexandre Agiova da Costa (Embrapa Caprinos e Ovinos

    Learning Styles and Motivations for Practicing English as a Foreign Language: A Case Study of Role-play in Two Ecuadorian Universities

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    This action research studies the Ecuadorian university students’ learning styles and motivations to practice English as a Foreign Language through Role-play. The sample is composed of 158 students from two national universities located in the Coastal region of Ecuador. They took part of Role-play practices in the English as a Foreign Language course during 2016-2017. The instruments applied were the Social Software Survey Used with Undergraduate Students; and a questionnaire designed ad hoc, by the research team named Likert Questionnaire Learners’ Motivations for Practicing English through Role-play. The results show participants' openness to cooperative learning and task-based learning. It is concluded that the learning styles that participants prefer is working in groups; situation that favours the implementation of English as a foreign language practices through role-play

    Role of prey and intraspecific density dependence on the population growth of an avian top predator

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    Exploring predator-prey systems in diverse ecosystems increases our knowledge about ecological processes. Predator population growth may be positive when conspecific density is low but predators also need areas with prey availability, associated with competition, which increases the risk of suffering losses but stabilises populations. We studied relationships between European rabbits Oryctolagus cuniculus (prey) and adult eagle owls Bubo bubo (predators) in south-western Europe. We assessed models explaining the predator population growth and stability. We estimated the abundance of rabbits and adult eagle owls during three years in eight localities of central-southern Spain. We explored models including rabbit and adult eagle owl abundance, accounting for yearly variations and including the locality as a random variable. We found that population growth of adult eagle owls was positive in situations with low conspecific abundance and tended to be negative but approaching equilibrium in situations of higher conspecific abundance. Population growth was also positively related to previous summer rabbit density when taking into account eagle owl conspecific abundance, possibly indicating that rabbits may support recruitment. Furthermore, abundance stability of adult eagle owls was positively related to previous winter-spring rabbit density, which could suggest predator population stabilisation through quick territory occupation in high-quality areas. These results exemplify the trade-off between prey availability and abundance of adult predators related to population growth and abundance stability in the eagle owl-rabbit system in south-western Europe. Despite rabbits have greatly declined during the last decades and eagle owls locally specialise on them, eagle owls currently have a favourable conservation status. As eagle owls are the only nocturnal raptor with such dependence on rabbits, this could point out that predators may overcome prey decreases in areas with favourable climate and prey in the absence of superior competitors with similar foraging mode.This study is a partial result from the I + D National Plan Projects CGL2005-02340 and CGL2009-10741, funded by the Spanish Ministry of Science and Innovation and EU-FEDER funds. J. Fernandez-de-Simon benefitted from an FPI scholarship (BES-2006-12562) funded by the Spanish Ministry of Science and Innovation and the European Social Fund.Peer Reviewe

    Influence of food abundance and quality on rabbit fluctuations : Conservation and management implications in Donana National Park (SW Spain)

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    Le lapin de garenne (Oryctolagus cuniculus) constitue la proie principale de plusieurs carnivores et rapaces menacés. Ces dernières années, une variété d'efforts a été déployée afin d'accroître les populations de lapins et ainsi augmenter la survie de ces prédateurs en danger de disparition. L'objet du présent travail était d'améliorer notre compréhension des facteurs qui jouent sur la variation naturelle des populations de lapins, en particulier ceux relatifs à l'abondance et à la qualité de la nourriture, et de discuter les efforts actuels en matière de gestion des populations de lapins. Des estimations de l'abondance des lapins furent obtenues chaque mois à partir de comptages routiers et ce durant une période de 25 mois dans le Parc National de Donana. Simultanément, des échantillons de la strate herbacée étaient recueillis sur la zone des recensements. Les fluctuations d'abondance des lapins furent comparées aux changements en biomasse et qualité des plantes herbacées. L'abondance des lapins s'est avérée être le mieux corrélée avec la disponibilité totale en protéines dans la strate herbacée. Les différences observées entre les valeurs maximales de l'abondance des lapins durant deux années consécutives furent dues à l'incidence de la première épizootie de virus hémorrhagique, couplée aux variations d'une année sur l'autre de la pluviométrie, ce qui affecta à la fois la disponibilité de la nourriture et la reproduction des lapins. L'importance relative des autres facteurs influençant les effectifs de lapins à Donana, incluant la myxomatose, la prédation et la compétition alimentaire avec les grands herbivores, est discutée

    Study of the light-induced metal-insulator transition in SrTiO3 by photoresistance spectroscopy

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    Photoresistivity and its spectral response has been systematically studied in oxygen deficient SrTiO3 single crystals for a wide range of resistivities, ρ, and carrier densities, n. At roomtemperature we have found a persistent photoresistance that gradually decreases as ρ is diminished or n is increased in addition to relaxation times of seconds to a few minutes suggesting that trapping of carriers is playing a major role. An analysis of the photoresistance excitation spectra shows two distinctive features that are related to the indirect gap of SrTiO3 at (3.25 ± 0.04) eV and to a direct transition at (3.40 ± 0.03) eV. The photoresistive crystals present a temperature dependent resisitivity under illumination that experiences a metal-insulator transition below T ∼ 85 K. Lowtemperature photoresistance spectrum reveals as a suitable technique to understand the origin of this transition, pointing to an enhanced efficiency of the ∼ 3.25 eV gap to promote electrons to the bottom of the conduction band.Fil: Bridoux, German. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Villafuerte, Manuel Jose. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ferreyra, J. M.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; ArgentinaFil: Bachi, N.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; ArgentinaFil: Figueroa, C. A.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; ArgentinaFil: Heluani, S. P.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentin
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