116 resultados para Origin country
Resumo:
The impact of burning and grazing on plant, ground beetle and spider species was investigated experimentally in stands of varying ages (burnt in 1982 and 1988 and unburnt plots) on an area of heather moorland in County Antrim, north-east Ireland. Burning initiated complex succession pathways which appear to have characteristic plant and invertebrate species associations. Removal of Calluna dominance initiated a period of high plant species diversity. Investigation of initial post-fire regeneration suggested that the frequency of occurrence of plant species changed over time and was affected by grazing. Grouping of species by the position of their renewal bud, i.e. their life-form, did not account for all observed interspecific variation. The dominant species after burning were Eriophorum vaginatum, E. angustifolium and Vaccinium myrtillus. Studies of vegetation canopy structure showed that, even with the exclusion of the main grazing herbivores, Calluna will not re-establish itself as the dominant species until several years after burning. The ground beetle Nebria salina was trapped more often on plots burnt in 1988 than on unburnt plots or those burnt in 1982. In comparison, Pterostichus niger and Carabus granulatus were trapped in greater numbers on plots burnt in 1982 than on unburnt plots and plots burnt in 1988. The large species Carabus problematicus and Carabus glabratus were trapped in greater numbers on unburnt plots. Similarly, more of the spiders Ceratinella brevipes and Centromerita concinna were trapped on the plots burnt in 1982. In comparison, Lepthyphantes zimmermanni and Robertus lividus were trapped more often on unburnt plots than on plots burnt in 1982 and 1988. Results are discussed with respect to the importance of the continuation of traditional heathland management practices.
Resumo:
Resumo:
Activity and selectivity are both important issues in heterogeneous catalysis and recent experimental results have shown that Ni catalysts doped by gold exhibit high activity for the hydrogenation of acetylene with good selectivity of ethylene formation. To unravel the underlying mechanism for this observation, the general trend of activity and selectivity of Ni surfaces doped by Au, Ag, and Cu has been investigated using density functional theory calculations. Complete energy profiles from C2H2 to C2H4 on Ni(111), Au/Ni(111), Ag/Ni(111) and Cu/Ni(111) are obtained and their turnover frequencies (TOFs) are computed. The results show that acetylene adsorption on Ni catalyst is strong which leads to the low activity while the doping of Au, Ag, and Cu on the Ni catalyst weakens the acetylene adsorption, giving rise to the increase of activity. The selectivity of ethylene formation is also quantified by using the energy difference between the hydrogenation barriers and the absolute value of the adsorption energies of ethylene. It is found that the selectivity of ethylene formation increases by doping Au and Ag, while those of Cu/Ni and Ni are similar.
Resumo:
Objectives: To evaluate a booklet on comfort care in dementia from the perspective of family with relevant experience, and assess nursing home resident and family factors associated with evaluations. Design: Retrospective study. Setting: Long term care facilities in French-speaking Canada, and the Netherlands and Italy.
Participants: Bereaved family (n = 138).
Measurements: An 8-item scale assessed the booklet's acceptability. Usefulness was rated on a 0 to 10 scale, and perceived usefulness referred to usefulness if family had had the booklet during the resident's stay. Families indicated preferred ways of obtaining, and the most appropriate time to get the booklet.
Results: Almost all families (94%) perceived the booklet as useful. Canadian and Dutch families evaluated the booklet's contents and format favorably, whereas Italian families' evaluations were less favorable. Almost all families endorsed roles for physicians or nurses and about half additionally accepted availability through own initiative, in print or through the Internet. Preference of timing was highly variable. Better acceptability, usefulness, and availability through own initiative were independently associated with non-Italian nationality, presence of more physical signs discussed in the booklet, feeling ill-prepared, and higher satisfaction with care. A preference of receiving the booklet early was more likely in Italian families, those without university education, and those involved with older residents.
Conclusion: The booklet is suitable to inform Dutch and Canadian families on comfort care in dementia, but implementation in Italy requires further consideration. The booklet may be integrated in advance care planning in long term care, and made available outside long term care settings to serve families who wish to be informed early. © 2012 American Medical Directors Association, Inc.
Keywords: Decision aid; decision making; advance care planning; palliative care; nursing homes; dementia.
Resumo:
The phragmoplast coordinates cytokinesis in plants [1]. It directs vesicles to the midzone, the site where they coalesce to form the new cell plate. Failure in phragmoplast function results in aborted or incomplete cytokinesis leading to embryo lethality, morphological defects, or multinucleate cells [2, 3]. The asymmetry of vesicular traffic is regulated by microtubules [1, 4, 5, 6], and the current model suggests that this asymmetry is established and maintained through treadmilling of parallel microtubules. However, we have analyzed the behavior of microtubules in the phragmoplast using live-cell imaging coupled with mathematical modeling and dynamic simulations and report that microtubules initiate randomly in the phragmoplast and that the majority exhibit dynamic instability with higher turnover rates nearer to the midzone. The directional transport of vesicles is possible because the majority of the microtubules polymerize toward the midzone. Here, we propose the first inclusive model where microtubule dynamics and phragmoplast asymmetry are consistent with the localization and activity of proteins known to regulate microtubule assembly and disassembly.
Resumo:
I originated, developed and wrote this one-hour documentary for RTE Television on newly discovered aspects of the life of WB Yeats. I am credited as producer and co-writer.