37 resultados para Skye


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Detailed oxygen, hydrogen and carbon isotope studies have been carried out on igneous and metamorphic rocks of the Stony Mountain complex, Colorado, and the Isle of Skye, Scotland, in order to better understand the problems of hydrothermal meteoric water-rock interaction.

The Tertiary Stony Mountain stock (~1.3 km in diameter), is composed of an outer diorite, a main mass of biotite gabbro, and an inner diorite. The entire complex and most of the surrounding country rocks have experienced various degrees of 18O depletion (up to 10 per mil) due to interaction with heated meteoric waters. The inner diorite apparently formed from a low-18O magma with δ18O ≃ +2.5, but most of the isotopic effects are a result of exchange between H2O and solidified igneous rocks. The low-18O inner diorite magma was probably produced by massive assimilation and/or melting of hydrothermally altered country rocks. The δ18O values of the rocks generally increase with increasing grain size, except that quartz typically has δ18O = +6 to +8, and is more resistant to hydrothermal exchange than any other mineral studied. Based on atom % oxygen, the outer diorites, gabbros, and volcanic rocks exhibit integrated water/rock ratios of 0.3 ± 0.2, 0.15 ± 0.1, and 0.2 ± 0.1, respectively. Locally, water/rock ratios attain values greater than 1.0. Hydrogen isotopic analyses of sericites, chlorites, biotites, and amphiboles range from -117 to -150. δD in biotites varies inversely with Fe/Fe+Mg, as predicted by Suzuoki and Epstein (1974), and positively with elevation, over a range of 600 m. The calculated δD of the mid-to-late-Tertiary meteoric waters is about -100. Carbonate δ13C values average -5.5 (PDB), within the generally accepted range for deep-seated carbon.

Almost all the rocks within 4 km of the central Tertiary intrusive complex of Skye are depleted in 18O. Whole-rock δ18O values of basalts (-7. 1 to +8.4), Mesozoic shales (-0.6 to + 12.4), and Precambrian sandstones (-6.2 to + 10.8) systematically decrease inward towards the center of the complex. The Cuillin gabbro may have formed from a 18O-depleted magma (depleted by about 2 per mil); δ18O of plagioclase (-7.1 to + 2.5) and pyroxene (-0.5 to + 3.2) decrease outward toward the margins of the pluton. The Red Hills epigranite plutons have δ18O quartz (-2.7 to + 7.6) and feldspar (-6.7 to + 6.0) that suggest about 3/4 of the exchange took place at subsolidus temperatures; profound disequilibrium quartz-feldspar fractionations (up to 12) are characteristic. The early epigranites were intruded as low-18O melts (depletions of up to 3 per mil) with δ18O of the primary, igneous quartz decreasing progressively with time. The Southern Porphyritic Epigranite was apparently intruded as a low-18O magma with δ18O ≃ -2.6. A good correlation exists between grain size and δ18O for the unique, high-18O Beinn an Dubhaich granite which intrudes limestone having a δ18O range of +0.5 to +20.8, and δ13C of -4.9 to -1.0. The δD values of sericites (-104 to -107), and amphiboles, chlorites, and biotites (-105 to -128) from the igneous rocks , indicate that Eocene surface waters at Skye had δD ≃ -90. The average water/rock ratio for the Skye hydrothermal system is approximately one; at least 2000 km3 of heated meteoric waters were cycled through these rocks.

Thus these detailed isotopic studies of two widely separated areas indicate that (1) 18O-depleted magmas are commonly produced in volcanic terranes invaded by epizonal intrusions; (2) most of the 18O-depletion in such areas are a result of subsolidus exchange (particularly of feldspars); however correlation of δ18O with grain size is generally preserved only for systems that have undergone relatively minor meteoric hydrothermal exchange; (3) feldspar and calcite are the minerals mos t susceptible to oxygen isotopic exchange, whereas quartz is very resistant to oxygen isotope exchange; biotite, magnetite, and pyroxene have intermediate susceptibilities; and (4) basaltic country rocks are much more permeable to the hydrothermal convective system than shale, sandstone, or the crystalline basement complex.

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Transactions of the Edinburgh Botanical Society, v. 1, 1844, p. 133-144.

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Peer reviewed

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Objective: To compare the location and accessibility of current Australian chronic heart failure (CHF) management programs and general practice services with the probable distribution of the population with CHF. Design and setting: Data on the prevalence and distribution of the CHF population throughout Australia, and the locations of CHF management programs and general practice services from 1 January 2004 to 31 December 2005 were analysed using geographic information systems (GIS) technology. Outcome measures: Distance of populations with CHF to CHF management programs and general practice services. Results: The highest prevalence of CHF (20.3–79.8 per 1000 population) occurred in areas with high concentrations of people over 65 years of age and in areas with higher proportions of Indigenous people. Five thousand CHF patients (8%) discharged from hospital in 2004–2005 were managed in one of the 62 identified CHF management programs. There were no CHF management programs in the Northern Territory or Tasmania. Only four CHF management programs were located outside major cities, with a total case load of 80 patients (0.7%). The mean distance from any Australian population centre to the nearest CHF management program was 332 km (median, 163 km; range, 0.15–3246 km). In rural areas, where the burden of CHF management falls upon general practitioners, the mean distance to general practice services was 37 km (median, 20 km; range, 0–656 km). Conclusion: There is an inequity in the provision of CHF management programs to rural Australians.

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Background Invasive species pose a significant threat to global economies, agriculture and biodiversity. Despite progress towards understanding the ecological factors associated with plant invasions, limited genomic resources have made it difficult to elucidate the evolutionary and genetic factors responsible for invasiveness. This study presents the first expressed sequence tag (EST) collection for Senecio madagascariensis, a globally invasive plant species. Methods We used pyrosequencing of one normalized and two subtractive libraries, derived from one native and one invasive population, to generate an EST collection. ESTs were assembled into contigs, annotated by BLAST comparison with the NCBI non-redundant protein database and assigned gene ontology (GO) terms from the Plant GO Slim ontologies. Key Results Assembly of the 221 746 sequence reads resulted in 12 442 contigs. Over 50 % (6183) of 12 442 contigs showed significant homology to proteins in the NCBI database, representing approx. 4800 independent transcripts. The molecular transducer GO term was significantly over-represented in the native (South African) subtractive library compared with the invasive (Australian) library. Based on NCBI BLAST hits and literature searches, 40 % of the molecular transducer genes identified in the South African subtractive library are likely to be involved in response to biotic stimuli, such as fungal, bacterial and viral pathogens. Conclusions This EST collection is the first representation of the S. madagascariensis transcriptome and provides an important resource for the discovery of candidate genes associated with plant invasiveness. The over-representation of molecular transducer genes associated with defence responses in the native subtractive library provides preliminary support for aspects of the enemy release and evolution of increased competitive ability hypotheses in this successful invasive. This study highlights the contribution of next-generation sequencing to better understanding the molecular mechanisms underlying ecological hypotheses that are important in successful plant invasions.

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Establishing healthy eating habits early in life is one important strategy to combat childhood obesity. Given that early maternal child feeding practices have been linked to child food intake and weight, identifying the maternal correlates of maternal child feeding practices is important in order to understand the determinants of childhood obesity; this was the overall aim of the current review. Academic databases were searched for studies examining the relationship between maternal child feeding practices and parenting, personal characteristics and psychopathology of mothers with preschoolers. Papers were limited to those published in English, between January 2000 - June 2012. Only studies with mothers of normally developing children between the ages of 2 - 6 years were included. There were no restrictions regarding the inclusion of maternal nationality or SES. Seventeen eligible studies were sourced. Information on the aim, sample, measures and findings of these was summarised into tables. The findings of this review support a relationship between maternal controlling parenting, general and eating psychopathology, and socioeconomic status and maternal child feeding practices. The main methodological issues of the studies reviewed included inconsistency in measures of maternal variables across studies and cross-sectional designs. We conclude that the maternal correlates associated with maternal child feeding practices are complex, and the pathways by which maternal correlates impact these feeding practices require further investigation.

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La version intégrale de ce mémoire est disponible uniquement pour consultation individuelle à la Bibliothèque de musique de l’Université de Montréal (www.bib.umontreal.ca/MU).

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[EN] In this paper we present a method for the regularization of a set of unstructured 3D points obtained from a sequence of stereo images. This method takes into account the information supplied by the disparity maps computed between pairs of images to constraint the regularization of the set of 3D points. We propose a model based on an energy which is composed of two terms: an attachment term that minimizes the distance from 3D points to the projective lines of camera points, and a second term that allows for the regularization of the set of 3D points by preserving discontinuities presented on the disparity maps. We embed this energy in a 2D finite element method. After minimizing, this method results in a large system of equations that can be optimized for fast computations. We derive an efficient implicit numerical scheme which reduces the number of calculations and memory allocations.

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BACKGROUND AND PURPOSE The DRAGON score predicts functional outcome in the hyperacute phase of intravenous thrombolysis treatment of ischemic stroke patients. We aimed to validate the score in a large multicenter cohort in anterior and posterior circulation. METHODS Prospectively collected data of consecutive ischemic stroke patients who received intravenous thrombolysis in 12 stroke centers were merged (n=5471). We excluded patients lacking data necessary to calculate the score and patients with missing 3-month modified Rankin scale scores. The final cohort comprised 4519 eligible patients. We assessed the performance of the DRAGON score with area under the receiver operating characteristic curve in the whole cohort for both good (modified Rankin scale score, 0-2) and miserable (modified Rankin scale score, 5-6) outcomes. RESULTS Area under the receiver operating characteristic curve was 0.84 (0.82-0.85) for miserable outcome and 0.82 (0.80-0.83) for good outcome. Proportions of patients with good outcome were 96%, 93%, 78%, and 0% for 0 to 1, 2, 3, and 8 to 10 score points, respectively. Proportions of patients with miserable outcome were 0%, 2%, 4%, 89%, and 97% for 0 to 1, 2, 3, 8, and 9 to 10 points, respectively. When tested separately for anterior and posterior circulation, there was no difference in performance (P=0.55); areas under the receiver operating characteristic curve were 0.84 (0.83-0.86) and 0.82 (0.78-0.87), respectively. No sex-related difference in performance was observed (P=0.25). CONCLUSIONS The DRAGON score showed very good performance in the large merged cohort in both anterior and posterior circulation strokes. The DRAGON score provides rapid estimation of patient prognosis and supports clinical decision-making in the hyperacute phase of stroke care (eg, when invasive add-on strategies are considered).