416 research outputs found

    Preparation de α-magnesyl-α-toluenesulfonate de sodium et quelques syntheses avec

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    L \u27acide a-toluenesÎŒlfonique, C6H5CH2S03H, qui est un analogue sulfonique de l\u27acide phenylacetique, C6H5CH2COOH, peut etre transforme en un reactif organomagnesien polyfonctionnel I. Au moyen de ce reactif on peut introduire dans des composes organiques le groupe sulfonique aliphatiquement lie. Ainsi avec la benzophenone et la cyclohexanone on obtient les acides B-hydroxysulfoniques correspondants II et III avec de bons rendements

    Preparation de α-magnesyl-α-toluenesulfonate de sodium et quelques syntheses avec

    Get PDF
    L \u27acide a-toluenesÎŒlfonique, C6H5CH2S03H, qui est un analogue sulfonique de l\u27acide phenylacetique, C6H5CH2COOH, peut etre transforme en un reactif organomagnesien polyfonctionnel I. Au moyen de ce reactif on peut introduire dans des composes organiques le groupe sulfonique aliphatiquement lie. Ainsi avec la benzophenone et la cyclohexanone on obtient les acides B-hydroxysulfoniques correspondants II et III avec de bons rendements

    The Quaternary lions of Ukraine and a trend of decreasing size in Panthera spelaea (advance online)

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    The fossil record of the cave lion, Panthera spelaea, suggests a gradual decrease in body size, the process peaking just before the extinction of the species at the end of the Late Pleistocene. Such an evolutionary trend appears rather unusual for a large felid species and requires further investigation. This study reviews the cave lions of Ukraine, whose fossils are known from 46 localities dated from 800 kyr to 18–17 kyr ago, with a special emphasis on size changes through time. We describe several important finds including those of Panthera spelaea fossilis from Sambir, Panthera spelaea ssp. from Bilykh Stin Cave and Panthera spelaea spelaea from Kryshtaleva Cave. We make subspecific identifications of specimens from the region and focus on their size characteristics. Our analysis of Ukrainian cave lions agrees with the temporal trend of decreasing size, particularly accelerating during MIS 2, as exemplified by the extremely small female skull from Kryshtaleva Cave. We provide a direct AMS date for this specimen (22.0–21.5 cal kyr BP), which suggests that the Kryshtaleva lioness must have belonged to a Panthera spelaea spelaea population forced south by the spreading ice sheet. We discuss some palaeoecological aspects of the evolutionary history and eventual extinction of the cave lion. Finally, we review the subfossil records of the extant lion Panthera leo known from several Ukrainian sites archaeologically dated to 6.4–2.0 kyr BP. These finds most probably represent the Persian lion Panthera leo persica

    A datamining approach to identifying spatial patterns of phosphorus forms in the Stormwater Treatment Areas in the Everglades

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    The Everglades ecosystem in Florida, USA, is naturally phosphorus (P) limited, and faces threats of ecosystem change and associated losses to habitat, biodiversity, and ecosystem function if subjected to high inflows of P and other nutrients. In addition to changes in historic hydropattern, upstream agriculture (sugar cane, vegetable, citrus) and urbanization has placed the Everglades at risk due to nutrient-rich runoff. In response to this threat, the Stormwater Treatment Areas (STAs) were constructed along the northern boundary of the Everglades as engineered ecological systems designed to retain P from water flowing into the Everglades. This research investigated data collected over a period from 2002 to 2014 from the interior of the STAs using data mining and analysis techniques including (a) exploratory methods such as Principal Component Analysis to test for patterns and groupings in the data, and (b) modelling approaches to test for predictive relationships between environmental variables. The purpose of this research was to reveal and compare spatial trends and relationships between environmental variables across the various treatment cells, flow-ways, and STAs. Common spatial patterns and their drivers indicated that the flow-ways do not function along simple linear gradients; instead forming zonal patterns of P distribution that may increasingly align with the predominant flow path over time. Findings also indicate that the primary drivers of the spatial distribution of P in many of these systems relate to soil characteristics. The results suggest that coupled cycles may be a key component of these systems; i.e. the movement and transformation of P is coupled to that of nitrogen (N)

    Healthy ageing and home: The perspectives of very old people in five European countries

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    This paper reports on in-depth research, using a grounded theory approach, to examine the ways in which very old people perceive healthy ageing in the context of living alone at home within urban settings in five European countries. This qualitative study was part of a cross-national project entitled ENABLE-AGE which examined the relationship between home and healthy ageing. Interviews explored the notion of healthy ageing, the meaning and importance of home, conceptualisations of independence and autonomy and links between healthy ageing and home. Data analysis identified five ways in which older people constructed healthy ageing: home and keeping active; managing lifestyles, health and illness; balancing social life; and balancing material and financial circumstances. Older people reflected on their everyday lives at home in terms of being engaged in purposeful, meaningful action and evaluated healthy ageing in relation to the symbolic and practical affordances of the home, contextualised within constructions of their national context. The research suggests that older people perceive healthy ageing as an active achievement, created through individual, personal effort and supported through social ties despite the health, financial and social decline associated with growing older. The physicality and spatiality of home provided the context for establishing and evaluating the notion of healthy ageing, whilst the experienced relationship between home, life history and identity created a meaningful space within which healthy ageing was negotiated

    Sedimentação da Lagoa Itapeva, RS, Brasil

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    Hydrodynamic factors that control sedimentation in the Itapeva Lake were assessed on the granulometric distribution map generated by the Pejrup’s diagram and by the analysis of the hydrodynamic action, which results from the waves in the lacustrine body. The texture patterns of bottom samples showed that there is significant hydrodynamic energy in the sedimentation process: the sand fraction prevails in the submerged margins whereas grain size decreases, from coarse silt to fine silt, moved towards the center. The content of organic matter also shows this pattern, with a steady increase in the central area of the lacustrine body and near the mouths of the TrĂȘs Forquilhas and Cardoso rivers. The main processes that determine sedimentation are mainly controlled by the amount of fluvial sediment, which is redistributed by the action of waves and currents resulting from the action of winds. The concentration of clay-sized grains is not very significant not only because there is low input by the rivers, but also because the wave agitation avoid this granulometric class from depositing on the lacustrine bottom. Fine sediment in the deepest spots and in the most sheltered areas shows the influence of less effective currents that enable deposition in these areas.Os fatores hidrodinĂąmicos que controlam a sedimentação na Lagoa Itapeva foram avaliados atravĂ©s do mapa de distribuição granulomĂ©trica gerado a partir do diagrama de Pejrup e da anĂĄlise da ação hidrodinĂąmica induzida pelas ondas no corpo lacustre. Os padrĂ”es texturais das amostras de fundo indicaram a presença de significativa energia hidrodinĂąmica atuante no processo de sedimentação, com predomĂ­nio da fração arenosa nas margens submersas e granodecrescĂȘncia para tamanhos silte grosso a fino em direção ao centro. O teor de matĂ©ria orgĂąnica tambĂ©m apresenta este padrĂŁo, com aumento gradativo na ĂĄrea central do corpo lacustre e nas proximidades das desembocaduras dos rios TrĂȘs Forquilhas e Cardoso. Os principais processos que condicionam a sedimentação na lagoa sĂŁo controlados pelo aporte de sedimentos fluviais, redistribuĂ­dos pela ação das ondas e correntes induzidas pela ação dos ventos. A concentração de grĂŁos tamanho argila Ă© pouco significativa, devido Ă  baixa inserção pelos rios, alĂ©m da agitação gerada por ondas sobre o piso lacustre, que dificulta a deposição desta classe granulomĂ©trica. A presença de sedimentos finos nos locais mais profundos e nas ĂĄreas mais abrigadas indica a influĂȘncia de correntes menos efetivas, permitindo a deposição nestes locais
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