298 research outputs found

    Gause's exclusion principle revisited: artificial modified species and competition

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    Gause's principle of competition between two species is studied when one of them is sterile. We study the condition for total extinction in the niche, namely, when the sterile population exterminates the native one by an optimal use of resources. A mathematical Lotka-Volterra non linear model of interaction between a native and sterile species is proposed. The condition for total extinction is related to the initial number MoM_{o} of sterile individuals released in the niche. In fact, the existence of a critical sterile-population value McM_{c} is conjectured from numerical analysis and an analytical estimation is found. When spatial diffusion (migration) is considered a critical size territory is found and, for small territory, total extinction exist in any case. This work is motived by the extermination agriculture problem of fruit flies in our region.Comment: 11 pages. Published in Jour.Phys.A Math.Gen. 33, 4877 (2000

    An annotated list of the Lepidoptera of Honduras

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    A biodiversity inventory of the Lepidoptera of Pico Bonito National Park and vicinity, in the Department of Atlantida of northern Honduras, was initiated in 2009 to obtain baseline data. We present a revised checklist of Honduran butterfly species (updated from the initial 1967 lists), as well as the first comprehensive list of Honduran moths. Our updated list includes 550 species of Papilionoidea, 311 Hesperioidea, and 1,441 moth species

    An annotated list of the Lepidoptera of Honduras

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    A biodiversity inventory of the Lepidoptera of Pico Bonito National Park and vicinity, in the Department of Atlantida of northern Honduras, was initiated in 2009 to obtain baseline data. We present a revised checklist of Honduran butterfly species (updated from the initial 1967 lists), as well as the first comprehensive list of Honduran moths. Our updated list includes 550 species of Papilionoidea, 311 Hesperioidea, and 1,441 moth species

    The duality between care and education in a nursery daily activities

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    This article has the as objective to verify concepts related to care and to educate, with nursery professionals. Some documents about children education were studied and some interviews and observations of the work were done with seven nursery professionals. The main focus were the activities related to care developed with children. Data were organized following the degrees: function of the nursery, education and care concepts. Data were submitted of quality analysis, allowing the confrontation between the theorical and empirical material. The results showed that official documents do not worry about the phase under discussion, letting inaccurate the relation between the activities of care and its educational role. This inexactness is noticed in the nursery professionals' speech. The activities of care are enclosed in child education, once in the vision of the professionals it has a corrective function. This aspect is justified by the lack of formation and by the fact of they entail this activity to their mothers' experience.Esse trabalho objetivou verificar conceitos relativos ao cuidar e educar, junto a profissionais de berçário. Foram estudados documentos sobre educação infantil e realizadas entrevistas e observações da prática de sete profissionais de berçários, com enfoque nas atividades de cuidados desenvolvidas com as crianças. Os dados foram organizados segundo categorias: função do berçário, conceito de educar e de cuidar e sofreram análise qualitativa, permitindo a confrontação entre o material empírico e o teórico. Os resultados mostraram que os documentos oficiais pouco discutem a fase em questão, deixando imprecisa a relação entre as atividades de cuidado e seu papel educacional. Essa imprecisão se reflete no discurso das profissionais do berçário. As atividades de cuidados passam a estar contidas na educação da criança, na medida em que, na visão das profissionais, têm função disciplinadora. Esse aspecto justifica-se pela falta de formação e pelo fato de vincularem esta atividade às suas experiências de mães

    Inclusão escolar e avaliações inclusivas

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    Como ensinar nos tempos de hoje, em meio aos desafios que nos cercam, e transpor as barreiras do não aprender em busca de aprendizagens significativas e autônomas? Nos dias atuais, é essencial um planejamento sólido e relevante, através do diagnóstico pontual sobre como se constituem as aprendizagens de cada estudante. Muitas são as facetas que consolidam as aprendizagens, sejam elas visuais, auditivas, cinestésicas; portanto, é preciso repensar a prática que respeite cada aprendente com suas necessidades, sejam especiais ou não, como sujeito único na sua forma de aprender

    Two approaches in scanner-printer calibration: colorimetric space-based vs. "closed-loop"

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    Studies two different table-based approaches for the calibration of electronic imaging systems. The first approach, which is the classical one, uses the device-independent CIE-XYZ colorimetric space as an intermediate standard space. Input and output devices such as scanners, displays and printers are calibrated separately with respect to the objective CIE-XYZ space. The calibration process requires establishing a 3D mapping between a scanner's device-dependent RGB space and a device-independent colorimetric space such as CIE-XYZ. Measured samples belonging to the calibration set are used for splitting the colorimetric space into Delaunay tetrahedrons. The second approach, the so-called “closed-loop” approach, directly calibrates scanner-printer pairs, without any reference to an objective colorimetric space. It enables a 3D mapping to be built between the scanner's RGB space and the printer's CMY space without requiring any colorimetric measurement. It offers very accurate calibrated output for input samples having the same characteristics (halftone dot, ink spectral reflectance) as the printed samples used for the calibration process. When the desktop scanners' RGB sensibilities are not a linear transform of the CIE x¯,y¯,z¯ matching curves, an accurate calibration can only be made if input color patches are based on the same primary inks as the patches used for device calibratio

    Integrated management of a Swiss cropland is not sufficient to preserve its soil carbon pool in the long term

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    Croplands are involved in the exchange of carbon dioxide (CO2) between the atmosphere and the biosphere. Furthermore, soil carbon (C) stocks play an important role in soil fertility. It is thus of great interest to know whether intensively managed croplands act as a net source or sink of atmospheric CO2 and if soil C stocks are preserved over long timescales. The FluxNet site CH-Oe2 in Oensingen, Switzerland, has been operational since the end of 2003. This cropland is managed under the Swiss framework of the Proof of Ecological Performance (PEP, a variant of integrated management) with a crop rotation centred on winter wheat, which also includes winter barley, winter rapeseed, peas, potato and intermediate cover crops. In addition to eddy covariance measurements, meteorological and soil measurements were available along with information on C imports and exports from organic fertilisation, sowing and harvesting. This study investigates cropland C budgets over 13 years and assesses whether the PEP regulations resulted in a balanced C budget. The strongest CO2 uptake was observed during cereal seasons. C export through harvest, however, offset the strong uptake of the cereal crops. The largest net CO2 emissions to the atmosphere were observed during pea and cover crop seasons. Net biome production, representing the overall C budget (assuming carbon leaching to groundwater to be negligible), typically ranged between close to C neutral to C losses of up to 407&thinsp;g&thinsp;C&thinsp;m−2 per season, with peas being the largest source. Overall, the field lost 1674&thinsp;g&thinsp;C&thinsp;m−2 over 13 years (129&thinsp;g&thinsp;C&thinsp;m−2&thinsp;yr−1), which was confirmed by soil C stock measurements at the beginning and the end of the study period. Although managing the field under the regulations of PEP did not result in an overall C sink, model simulations showed that the use of cover crops reduced the C losses compared to leaving the field bare. The use of solid manure improved the C budget by importing substantial amounts of C into the soil, while liquid manure had only a small effect. We thus conclude that additional efforts are needed to bring Swiss management practices closer to the goal of preserving soil C in the long term.</p
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