3,462 research outputs found

    Estimation of the finite right endpoint in the Gumbel domain

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    A simple estimator for the finite right endpoint of a distribution function in the Gumbel max-domain of attraction is proposed. Large sample properties such as consistency and the asymptotic distribution are derived. A simulation study is presented

    Treatment of bimodality in proficiency test of pH in bioethanol matrix

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    The pH value in bioethanol is a quality control parameter related to its acidity and to the corrosiveness of vehicle engines when it is used as fuel. In order to verify the comparability and reliability of the measurement of pH in bioethanol matrix among some experienced chemical laboratories, reference material (RM) of bioethanol developed by Inmetro - the Brazilian National Metrology Institute - was used in a proficiency testing (PT) scheme. There was a difference of more than one unit in the value of the pH measured due to the type of internal filling electrolytic solutions (potassium chloride, KCl or lithium chloride, LiCl) from the commercial pH combination electrodes used by the participant laboratories. Therefore, bimodal distribution has occurred from the data of this PT scheme. This work aims to present the possibilities that a PT scheme provider can use to overcome the bimodality problem. Data from the PT of pH in bioethanol were treated by two different statistical approaches: kernel density model and the mixture of distributions. Application of these statistical treatments improved the initial diagnoses of PT provider, by solving bimodality problem and contributing for a better performance evaluation in measuring pH of bioethanol.Comment: 20 pages, 6 figures, Accepted for publication in Accreditation and Quality Assurance (ACQUAL

    Juncus emmanuelis

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    This species is endemic to a small area in the southwestern Iberian Peninsula, with subpopulations scattered in approximately 16 localities. It is assessed as Endangered (EN B2ab(ii,iii,iv)) because it has an Area of Occupancy (AOO) of less than 500 km2 and shows signs of severe fragmentation due to the ongoing transformation of its specific habitat of sandy soils with an impermeable underlayer in temporary pools, as a result of several ongoing major threats associated with intensive agricultural activities. Based on this information, a continuing decline in the AOO, habitat quality and number of subpopulations has been inferred. Additional research and conservation action is needed for this species

    Zannichellia contorta

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    This species is native to southern, central and eastern Spain, with an old record from the Atlas Mountains in northern Morocco requiring confirmation. The species is very sensitive to eutrophication and deterioration of water quality. The Area of Occupancy (AOO) has been estimated to be less than 500 km2 based on confirmed records and knowledge that its habitat is in continuous decline and at least 40% of the known localities have disappeared, especially in southern Spain. Moreover, an ongoing continuing decline in AOO, habitat quality and number of subpopulations of this species due to the increase in nutrients concentration from waters of the streams where it lives, which stops its growth, has been observed. The same process of habitat deterioration is happening in central and eastern Spain. The population of this species is severely fragmented with more than half of its subpopulations being isolated with no exchange possibilities and suspected to have reached no viable levels. It therefore qualifies to be listed in the category Endangered (EN B2ab(ii,iii,iv)) in the Mediterranean region. Resource and habitat protection and site management are needed. Other recommended conservation measures are ex situ conservation, population and distribution research, and habitat and population monitoring

    Narcissus dubius, Narcisse Douteux

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    This species is endemic to southern France and eastern Spain. It is assessed as Least Concern because it has a widespread distribution, occurs in several protected areas throughout its range and its population is not expected to significantly decline in the near future. Further studies on the genetic structure of its population and trends in population size at global level are needed

    Anthocyanin actions at the gastrointestinal tract: Relevance to their health benefits

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    Anthocyanins (AC) are flavonoids abundant in the human diet, which consumption has been associated to several health benefits, including the mitigation of cardiovascular disease, type 2 diabetes, non-alcoholic fatty liver disease, and neurological disorders. It is widely recognized that the gastrointestinal (GI) tract is not only central for food digestion but actively participates in the regulation of whole body physiology. Given that AC, and their metabolites reach high concentrations in the intestinal lumen after food consumption, their biological actions at the GI tract can in part explain their proposed local and systemic health benefits. In terms of mechanisms of action, AC have been found to: i) inhibit GI luminal enzymes that participate in the absorption of lipids and carbohydrates; ii) preserve intestinal barrier integrity and prevent endotoxemia, inflammation and oxidative stress; iii) sustain goblet cell number, immunological functions, and mucus production; iv) promote a healthy microbiota; v) be metabolized by the microbiota to AC metabolites which will be absorbed and have systemic effects; and vi) modulate the metabolism of GI-generated hormones. This review will summarize and discuss the latest information on AC actions at the GI tract and their relationship to overall health benefits.Fil: Oteiza, Patricia I.. University of California at Davis; Estados UnidosFil: Cremonini, Eleonora. University of California at Davis; Estados UnidosFil: Fraga, César Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentin

    Validation of the Software “Recycling of Nutrients” in Dairy-Farms of Western Cuba

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    To maintain a good productivity in the soil-plant-animal system it is necessary to achieve an equilibrium between input and output of nutrients and energy. Models and simulation software have been proposed for this purpose. For dairy farms, models have been utilised to show the behaviour of different aspects, such as: feed utilisation, energy flow, digestibility values and daily weight gains (Freer et al., 1970; Assis & France, 1983, Bruce et al., 1984). However, there are few models showing the interaction between soil-plant- animal components of these systems. The objective of the present study was to validate the software Recycling of Nutrients proposed by Ortiz (2000) for dairy farms of western Cuba

    Recuperação de atributos físicos de um argissolo em função do seu revolvimento e do tempo de semeadura direta.

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    A melhoria da qualidade estrutural do solo pelo uso continuado do sistema semeadura direta ocorre junto com o processo de sua (re)acidificação. Em algumas circunstâncias, ocorre também compactação superficial devido ao tráfego de máquinas, que necessita ser corrigida pela mobilização do solo. Assim, em experimento conduzido há 12 anos sob diferentes sistemas de manejo do solo, avaliou-se o tempo necessário para o solo readquirir os atributos físicos iniciais, alterados no processo de revolvimento do solo, por ocasião da reaplicação de calcário. O experimento foi realizado na Estação Experimental Agronômica da UFRGS, em Eldorado do Sul - RS, em um Argissolo Vermelho distrófico típico. Os sistemas de manejo avaliados foram: (a) preparo convencional durante 12 anos, (b) sistema semeadura direta com revolvimento do solo para incorporar calcário a cada quatro anos, (c) sistema semeadura direta durante oito anos e (d) sistema semeadura direta durante 12 anos. Determinaram-se, imediatamente antes e 6, 12, 24, 36 e 48 meses depois da terceira reaplicação de calcário, a densidade, a porosidade total, a macroporosidade, a microporosidade, a estabilidade de agregados e o teor de C orgânico em três camadas (0,0-2,5; 2,5-7,5 e 7,5-15,0 cm) de solo. O revolvimento do solo para incorporação do calcário no sistema semeadura direta de quatro anos propiciou condições mais favoráveis de densidade e porosidade do solo, mas diminuiu a estabilidade de agregados. Houve necessidade de um período de quatro anos de cultivo do solo no sistema semeadura direta para o retorno da estabilidade de agregados à condição original. Os atributos físicos do solo foram mais uniformes no perfil no preparo convencional, porém com menor estabilidade de agregados na camada superficial, que foi relacionada ao teor de C orgânico
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