781 research outputs found

    A Graph Grammar to Transform a Dataflow Graph into a Multithread Graph and its Application in Task Scheduling

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    The scheduling of tasks in a parallel program is an NP-complete problem, where scheduling tasks over multiple processing units requires an effective strategy to maximize the exploitation of the parallel hardware. Several studies focus on the scheduling of parallel programs described into DAGs (Directed Acyclic Graphs). However, this representation does not describe a multithreaded program suitably. This paper shows the structure and semantics of a DCG, an abstraction which describes a multithreaded program, and proposes standards to map structures found in DAGs into segments of a DCG. A graph grammar has been developed to perform the proposed transformation and case studies using DAGs found in the literature validate the transformation process. Besides the automatic translation and precise definition of the mapping, the use of a formal language also allowed the verification of the existence and uniqueness of the out coming model.

    Cytokine production in experimental paracoccidioidomycosis of murine selected lineages for acute inflammatory response (AIR)

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    Paracoccidioidomycosis is a systemic human mycosis caused by Paracoccidioides brasiliensis (P. brasiliensis), an imperfect dimorphic fungus whose conidia are its infective form. Mice genetically selected for maximum (AIRmax) and minimum (AIRmin) acute inflammatory response were used as experimental paracoccidioidomycosis models. The animals were intraperitoneally inoculated with P. brasiliensis (strain 18) and killed 6, 12 and 24 hours or 3, 7 and 14 days after infection. In these periods, fragments from their spleen, liver and lung were removed for evaluation of the infection level by fungal cells, assessment of macrophagic activity by peritoneal and splenic macrophages - through the determination of nitric oxide (NO) concentrations and production of pro- and anti-inflammatory cytokines of lung and spleen homogenate supernatants. In the present study, it was observed that AIRmax lineages presented greater control of the infectious process than the AIRmin ones. Regarding NO production, AIRmax animals produced more metabolites in late periods, what may help control the infectious process. Concerning cytokine production, it was observed that the production of INF-gamma, TNF-alpha, IL-1, IL-6, IL-8 and IL-12 were increased in AIRmax lineages in most analyzed organs and periods, thus contributing to the greater resistance exhibited by such lineages against infection, except for IL-4 and IL-10 that showed decreased production in AIRmax lineage, reproducing its suppressive biological effect. From these results, it was observed that the AIRmax lineage was more effective in controlling the infectious process, with an important involvement of the analyzed cytokines. These findings are probably related to the genetically selected factors involved in the acute inflammatory response

    Laboratory and field leaching tests for predicting the environmental impact of Portuguese steel slag

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    The use of waste in the construction of Portuguese public works is feasible if there are no risks for the environment. The materials that meet these requirements in Portugal are those admissible for landfills of inert waste, their classification being done on the basis of the comparison of the leaching values obtained in standard laboratory leach tests with the leaching limit values established in the Portuguese legislation. This paper addresses the results of the leaching tests performed in laboratory and in the field with materials coming from electrical arc furnace steel slag produced in the Portuguese Iron and Steel Company

    The UV/H2O2 - photodegradation of poly(ethyleneglycol) and model compounds

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    The general mechanism for the photodegradation of polyethyleneglycol (PEG) by H2O2/UV was determined studying the photooxidation of small model molecules, like low molecular weight ethyleneglycols (tetra-, tri-, di-, and ethyleneglycol). After 30 min of irradiation the average molar mass (Mw) of the degradated PEG, analysed by GPC, fall to half of its initial value, with a concomitant increase in polydispersitivity and number of average chain scission (S), characterizing a random chain scission process yielding oligomers and smaller size ethyleneglycols. HPLC analysis of the photodegradation of the model ethyleneglycols proved that the oxidation mechanism involved consecutive reactions, where the larger ethyleneglycols gave rise, successively, to smaller ones. The photodegradation of ethyleneglycol lead to the formation of low molecular weight carboxylic acids, like glycolic, oxalic and formic acids.O mecanismo geral para a fotodegradação do polietilenoglicol (PEG) usando o sistema H2O2/UV foi determinado por GPC e HPLC, analisando o comportamento de moléculas modelo, como por exemplo os etilenoglicóis de baixa massa molar (tetra-, tri-, di-, e etilenoglicol). Após 30 min de irradiação, a massa molar ponderal média (Mw) do PEG degradado, analisada por GPC, cai para metade do seu valor inicial com um aumento concomitante na polidispersidade e número médio de quebra de cadeia (S). Essa queda acentuada caracteriza uma quebra de cadeia aleatória, formando oligômeros e etilenoglicóis de menor massa molar. A análise da fotodegradação de etilenoglicóis modelo por HPLC permitiu sugerir um mecanismo que envolve processos consecutivos, em que etilenoglicóis maiores originam menores, sucessivamente. A fotodegradação do etilenoglicol formou ácidos carboxílicos de baixa massa molar, como por exemplo os ácidos glicólico, oxálico e fórmico.FAPESPCNP

    Study of age-related changes in postural control during quiet standing through Linear Discriminant Analysis

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    <p>Abstract</p> <p>Background</p> <p>The human body adopts a number of strategies to maintain an upright position. The analysis of the human balance allows for the understanding and identification of such strategies. The displacement of the centre of pressure (COP) is a measure that has been successfully employed in studies regarding the postural control. Most of these investigations are related to the analysis of individuals suffering from neuromuscular disorders. Recent studies have shown that the elderly population is growing very fast in many countries all over the world, and therefore, researches that try to understand changes in this group are required. In this context, this study proposes the analysis of the postural control, measured by the displacement of the COP, in groups of young and elderly adults.</p> <p>Methods</p> <p>In total 59 subjects participated of this study. They were divided into seven groups according to their age. The displacement of the COP was collected for each subject standing on a force plate. Two experimental conditions, of 30 seconds each, were investigated: opened eyes and closed eyes. Traditional and recent digital signal processing tools were employed for feature computation from the displacement of the COP. Statistical analyses were carried out in order to identify significant differences between the features computed from the distinct groups that could allow for their discrimination.</p> <p>Results</p> <p>Our results showed that Linear Discrimination Analysis (LDA), which is one of the most popular feature extraction and classifier design techniques, could be successfully employed as a linear transformation, based on the linear combination of standard features for COP analysis, capable of estimating a unique feature, so-called <it>LDA-value</it>, from which it was possible to discriminate the investigated groups and show a high correlation between this feature and age.</p> <p>Conclusion</p> <p>These results show that the analysis of features computed from the displacement of the COP are of great importance in studies trying to understand the ageing process. In particular, the <it>LDA-value </it>showed to be an adequate feature for assessment of changes in the postural control which can be related to functional changes that occur over the ageing.</p

    A Graphite-Polyurethane Composite Electrode for the Analysis of Furosemide

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    A graphite-polyurethane composite electrode has been used for the determination of furosemide, a antihypertensive drug, in pharmaceutical samples by anodic oxidation. Cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize the electrooxidation process at +1.0 V vs. SCE over a wide pH range, with the result that no adsorption of analyte or products occurs, unlike at other carbon-based electrode materials. Quantification was carried out using cyclic voltammetry, differential pulse voltammetry, and square-wave voltammetry. Linear ranges were determined (up to 21 mumol L-1 with cyclic voltammetry) as well as limits of detection (0.15 mumol L-1 by differential pulse voltammetry). Four different types of commercial samples were successfully analyzed. Recovery tests were performed which agreed with those obtained by spectrophotometric evaluation. The advantages of this electrode material for repetitive analyzes, due to the fact that no electrode surface renewal is needed owing to the lack of adsorption, are highlighted

    Coring the sedimentary expression of the early Toarcian Oceanic Anoxic Event: New stratigraphic records from the Tethys Ocean

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    The Toarcian Oceanic Anoxic Event (T-OAE) interval was cored at Colle di Sogno and Gajum in the Lombardy Basin (Southern Alps, northern Italy). The Sogno and Gajum cores recovered 26.83 and 31.18 stratigraphic metres, respectively, of pelagic sediments consisting of marly limestones, marlstone, marly claystone, and black shale. Drilling at both sites resulted in 100\u2009% recovery of unweathered material. The pelagic succession comprises a relatively expanded black shale interval of 4.98\u2009m in the Sogno core and 15.35\u2009m in the Gajum core, with lower and upper boundaries without evidence of hiatuses. The Sogno and Gajum cores can be considered reference sections for the pelagic lower Toarcian interval of the western Tethys and will provide high-resolution micropaleontological, inorganic and organic geochemical, isotopic multiproxy data. Integrated stratigraphy and cyclostratigraphy are predicted to result in estimates of durations and rates to model the ecosystem resilience to the extreme perturbations of the T-OAE and gain a better understanding of current global changes and help provide better projections of future scenarios
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