824 resultados para Group of Eight


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Experimental values for the solubility of carbon dioxide, ethane, methane, oxygen, nitrogen, hydrogen, argon and carbon monoxide in 1-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF6] - a room temperature ionic liquid - are reported as a function of temperature between 283 and 343 K and at pressures close to atmospheric. Carbon dioxide is the most soluble and hydrogen is the least soluble of the gases studied with mole fraction solubilities of the order of 10-2 and 10-4, respectively. All the mole fraction solubilities decrease with temperature except for hydrogen for which a maximum is observed at temperatures close to 310 K. From the variation of solubility, expressed as Henry's law constants, with temperature, the partial molar thermodynamic functions of solvation such as the standard Gibbs energy, the enthalpy, and the entropy are calculated. The precision of the experimental data, considered as the average absolute deviation of the Henry's law constants from appropriate smoothing equations, is better than ±1%. © 2005 Elsevier B.V. All rights reserved.

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Purpose: The authors present the unique clinical features of cavitary uveal melanoma. Design: Retrospective chart review. Participants: Eight patients with cavitary uveal melanoma. Main Outcome Measures: The clinical, ultrasonographic, and histopathologic features of eight patients with cavitary melanoma of the ciliary body were studied. Results: In all eyes there was a brown ciliary body mass that blocked transmission of light on trans-scleral transillumination. Ocular ultrasonography revealed a large, single hollow cavity (unilocular 'pseudocyst') in five cases and multiple hollow cavities (multilocular 'pseudocyst') in three cases. The cavity occupied a mean of 55% of the entire mass thickness (range, 31%-79%). In five cases, a basal uveal mass was noted on ultrasonography. Four patients underwent tumor resection; one had enucleation, and three had 1251 radioactive plaque treatment. In the five cases confirmed histopathologically, the cavitation was empty, contained erythrocytes, serous fluid, and/or pigment-laden macrophages. In no case was the cavity lined by necrotic tumor, endothelial cells, or epithelial cells. Conclusion: Ciliary body melanoma can develop an intralesional cavity resembling an intraocular cyst. The presence of a solid mass at the base and a thick wall surrounding the cavity can assist in the differentiation of cavitary melanoma from benign cyst.

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Eight new microsatellite loci were isolated and characterized for the Natterer's bat Myotis nattereri from a microsatellite-enriched genomic library. The usefulness of these markers was assessed by screening a sample comprising 100 specimens collected from throughout the species range in Europe. Both moderately and highly polymorphic loci were identified with 3-17 alleles segregating per locus (mean 8.1 SE +/- A 0.048). No evidence for departure from HWE or linkage disequilibrium among loci was observed. These markers will provide a valuable addition to the molecular toolbox currently available for studies of population genetic structure, parentage and social organisation of M. nattereri and related species.

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This paper employs a unique decentralised cooperative control method to realise a formation-based collision avoidance strategy for a group of autonomous vehicles. In this approach, the vehicles' role in the formation and their alert and danger areas are first defined, and the formation-based intra-group and external collision avoidance methods are then proposed to translate the collision avoidance problem into the formation stability problem. The extension–decomposition–aggregation formation control method is next employed to stabilise the original and modified formations, whilst manoeuvring, and subsequently solve their collision avoidance problem indirectly. Simulation study verifies the feasibility and effectiveness of the intra-group and external collision avoidance strategy. It is demonstrated that both formation control and collision avoidance problems can be simultaneously solved if the stability of the expanded formation including external obstacles can be satisfied.

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It has been estimated that one out of forty people in the general population suffer from congenital prosopagnosia (CP), a neurodevelopmental disorder characterized by difficulty identifying people by their faces. CP involves impairment in recognising faces, although the perception of non-face stimuli may also be impaired. Given that social interaction does not only depend on face processing, but also the processing of bodies, it is of theoretical importance to ascertain whether CP is also characterised by body perception impairments. Here, we tested eleven CPs and eleven matched control participants on the Body Identity Recognition Task (BIRT), a forced-choice match-to-sample task, using stimuli that require processing of body, not clothing, specific features. Results indicated that the group of CPs was as accurate as controls on the BIRT, which is in line with the lack of body perception complaints by CPs. However the CPs were slower than controls, and when accuracy and response times were combined into inverse efficiency scores (IES), the group of CPs were impaired, suggesting that the CPs could be using more effortful cognitive mechanisms to be as accurate as controls. In conclusion, our findings demonstrate CP may not generally be limited to face processing difficulties, but may also extend to body perception

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Total phenol, hydroxycinnamic acid derivatives, flavone/flavonol and flavanones/dihydroflavonol contents of hydro-alcoholic extracts, obtained by sonication, from the aerial parts of Artemisia campestris L., Anthemis arvensis L., Haloxylon scoparium Pomel, Juniperus phoenicea L., Arbutus unedo L., Cytisus monspessulanus L., Thymus algeriensis Boiss et Reut, Zizyphus lotus L (Desf.) collected in Djebel Amour (Sahara Atlas, Algeria) were quantified by spectrophotometric methods. The chemical composition of the essential oils obtained by hydrodistillation from Artemisia campestris L. and Juniperus phoenicea I aerial parts were also evaluated by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). The antioxidant activity of the extracts and essential oils was assessed measuring the capacity for preventing lipid peroxidation using two lipidic substrates (egg yolk and liposomes), the capacity for scavenging DPPH, ABTS, superoxide anion radicals, hydroxyl radicals and peroxyl radicals. Anti-inflammatory activity was assessed by measuring the capacity for inhibiting lipoxygenase. Reducing power and chelating capacity were also assayed. The results showed different amounts of total phenols depending on the method used: A. campestris extract had the highest levels of total phenols when the measurement was made at lambda = 280 nm, whereas H. scoparium and A. unedo extracts showed the highest levels of total phenols with Folin-Ciocalteau. C. monspessulanus had the highest levels of flavones/flavonols and flavanones/dihydroflavonols. The essential oils of A. campestris and J. phoenicea were mainly constituted by alpha-pinene, beta-pinene and sabinene; and a-pinene, respectively. The methods used for assaying the capacity for preventing lipid peroxidation revealed to be inadequate for extracts due to the great interferences detected. The essential oils were more active than the generality of extracts for scavenging peroxyl radicals and for inhibiting lipoxygenase, whereas A. unedo extract was the most active for scavenging ABTS, DPPH, superoxide anion radicals and it also had the best reducing capacity. In a general way, the great majority of the antioxidant activities correlated well with the phenol content although such correlation was not so clear with the flavonoid content. (c) 2013 Elsevier B.V. All rights reserved.

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Tese de doutoramento, Biologia (Biologia Celular), Universidade de Lisboa, Faculdade de Ciências, 2016

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With the 2010 Vancouver Winter Olympic Games quickly approaching, there has been a heightened interest in the performance of Canadian athletes at international competitions (Duffy, 2007; Fidlin, 2005; Longley, 2006). Two significant documents outline Canada's goal to become the number one sporting nation at the 2010 Olympic Games, and improve Canada's performance at the 2008 Olympic Games: Own the Podium and Road to Excellence (Priestner Allinger & Allinger, 2004; Road to Excellence, 2006). These two documents represent heightened interest in the performance of our elite athletes, in conjunction with Canada's hosting status of the Vancouver 2010 Winter Olympic Games. The requirements to train and compete at the international level have become more demanding both in terms of financial resources and time commitment. The need to financially assist athletes with their training and competition costs has been an important topic of debate over the past decades (Beamish & Borowy, 1987; Gatehouse, 2004; Macintosh, 1996; Munro, 1970; Owens, 2004). Two sources of fiinding for high performance athletes in Canada are the Athlete Assistance Program (AAP) provided by the Federal Government and the Canadian Olympic Excellence Fund provided by the Canadian Olympic Committee. The importance of these fiinds for athletes has been discussed in various forums (Ekos, 1992, 1997, 2005; Priestner Allinger & Allinger, 2004; Thibault «& Babiak, 2005). However, alternative sources of funds for high performance athletes have never been the object of research. As such the purpose of this study was to describe a group of athlete applicants from the time period of November 2004 to April 2006, and to contextualize these applications within the development of the Charitable Fund for Athletes.

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Vitamin D metabolites are important in the regulation of bone and calcium homeostasis, but also have a more ubiquitous role in the regulation of cell differentiation and immune function. Severely low circulating 25-dihydroxyvitamin D [25(OH)D] concentrations have been associated with the onset of active tuberculosis (TB) in immigrant populations, although the association with latent TB infection (LTBI) has not received much attention. A previous study identified the prevalence of LTBI among a sample of Mexican migrant workers enrolled in Canada's Seasonal Agricultural Workers Program (SA WP) in the Niagara Region of Ontario. The aim of the present study was to determine the vitamin D status of the same sample, and identify if a relationship existed with LTBI. Studies of vitamin D deficiency and active TB are most commonly carried out among immigrant populations to non-endemic regions, in which reactivation of LTBI has occurred. Currently, there is limited knowledge of the association between vitamin D deficiency and LTBI. Entry into Canada ensured that these individuals did not have active TB, and L TBI status was established previously by an interferon-gamma release assay (IGRA) (QuantiFERON-TB Gold In-Tube®, Cellestis Ltd., Australia). Awareness of vitamin D status may enable individuals at risk of deficiency to improve their nutritional health, and those with LTBI to be aware of this risk factor for disease. Prevalence of vitamin D insufficiency among the Mexican migrant workers was determined from serum samples collected in the summer of 2007 as part of the cross sectional LTBI study. Samples were measured for concentrations of the main circulating vitamin D metabolite, 25(OH)D, with a widely used 1251 250HD RIA (DiaSorin Inc.®, Stillwater, MN), and were categorized as deficient «37.5 nmoI/L), insufficient (>37.5 nmollL, < 80 nmol/L) or sufficient (2::80 nmoI/L). Fisher's exact tests and t tests were used to determine if vitamin D status (sufficiency or insufficiency) or 25(OH)D concentrations significantly differed by sex or age categories. Predictors of vitamin D insufficiency and 25(OH)D concentrations were taken from questionnaires carried out during the previous study, and analyzed in the present study using multiple regression prediction models. Fisher's exact test and t test was used to determine if vitamin D status or 25(OH)D concentration differed by LTBI status. Strength of the relationship between interferongamma (IFN-y) concentration (released by peripheral T cells in response to TB antigens) and 25(OH)D concentration was analyzed using a Spearman correlation. Out of 87 participants included in the study (78% male; mean age 38 years), 14 were identified as LTBI positive but none had any signs or symptoms of TB reactivation. Only 30% of the participants were vitamin D sufficient, whereas 68% were insufficient and 2% were deficient. Significant independent predictors of lower 25(OH)D concentrations were sex, number of years enrolled in the SA WP and length of stay in Canada. No significant differences were found between 25(OH)D concentrations and LTBI status. There was a significant moderate correlation between IFN-y and 25(OH)D concentrations ofLTBI-positive individuals. The majority of participants presented with Vitamin D insufficiency but none were severely deficient, indicating that 25(OH)D concentrations do not decrease dramatically in populations who temporarily reside in Canada but go back to their countries of origin during the Canadian winter. This study did not find a statistical relationship between low levels of vitamin D and LTBI which suggests that in the presence of overall good health, lower than ideal levels of 2S(OH)D, may still be exerting a protective immunological effect against LTBI reactivation. The challenge remains to determine a critical 2S(OH)D concentration at which reactivation is more likely to occur.

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Please consult the paper edition of this thesis to read. It is available on the 5th Floor of the Library at Call Number: Z 9999 C54 O46 2007

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Four men (unidentified) walking in tunnel wearing hard hats and carrying flashlights.