594 resultados para 1081


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A series of enantiopure 2,2'-bipyridines have been synthesised from the corresponding cis-dihydrodiol metabolites of 2-chloroquinolines. Several of the resulting hydroxylated 2,2'-bipyridines were found to be useful chiral ligands for the asymmetric aminolysis of meso-epoxides leading to the formation of enantioenriched amino alcohols (-> 84%ee). N-oxide and N,N'-dioxide derivatives of these 2,2'-bipyridines, including separable atropisomers, have been synthesised and used as enantioselective organocatalysts in the asymmetric allylation of aldehydes to give allylic alcohols (-> 86%ee).

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The study explored the relationship between student wellbeing and academic achievement among 7–11 years old students and whether the relationship was moderated by gender and deprivation. 1081 students in Northern Ireland participated in a crosssectional survey that captured data on academic achievement and a range of wellbeing indicators. Findings suggested the existence of an underlying wellbeing factor, which was positively related to achievement. The relationship was not moderated by gender and/or deprivation. Findings were explored using a model of ‘academic buoyancy’. There was no evidence that suggested efforts to improve achievement that focus on wellbeing should be targeted speci?cally at students in economically deprived areas or be modi?ed in terms of gender.

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Laser desorption of dye-tagged oligonucleotides was studied using laser-induced fluorescence imaging. Desorption with ultra violet (UV) and infra-red (IR) lasers resulted in forward directed plumes of molecules. In the case of UV desorption, the initial shot desorbed approximately seven-fold more material than subsequent shots. In contrast, the initial shot in IR desorption resulted in the ejection of less material compared to subsequent shots and these plumes had a component directed along the path of the laser. Thermal equilibrium of the molecules in the plume was achieved after approximately 25 µs with a spread in molecular temperature which was described by a modified Maxwell-Boltzmann equation.

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Background: Patients with Barrett's oesophagus have an increased risk of oesophageal adenocarcinoma but this cancer only accounts for a small proportion of deaths in these patients. Other causes of death are reportedly raised in this group. We examined cause specific mortality among individuals in a population based Barrett's oesophagus register. Methods: We constructed a register of all patients diagnosed with columnar mucosa (including specialised intestinal metaplasia) of the oesophagus within Northern Ireland between 1993 and 1999. Deaths occurring within this cohort until 31 December 2000 were identified and mortality rates were compared with the general population. Results: Overall mortality was not raised in Barrett's patients. During 7413 person years of follow up in 2373 patients there were 253 deaths (standardised mortality ratio (SMR) 96 (95% confidence interval (CI) 84-107)). Mortality from oesophageal cancer was raised in patients with specialised intestinal metaplasia (SMR 774 (95% CI 317-1231 )) but only 4.7% of patients died from this cancer. Mortality from stroke (SMR 65 (95% CI 37-93)) was significantly lower than the general population while mortality from non-cancerous digestive system diseases was significantly higher (SMR 211 (95% CI 111-311)). Mortality rates from all other causes were similar to those of the general population. Conclusions: This study demonstrates that the overall mortality rate in patients with Barrett's oesophagus is closely similar to that of the general population. Oesophageal cancer mortality was raised but is an uncommon cause of death in these patients who also appear to have a reduced risk of death from stroke.

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A strong link between research and practice is essential to ensure
that the best available evidence gets into the hands of child welfare
practitioners, who are faced with the daunting task of making decisions
about vulnerable children on a daily basis. In 2007, a group of
senior child welfare leaders in the province of Ontario (Canada) created
a research dissemination model that replicated the worldrenowned
UK program, Research in Practice (http://www.rip.org.
uk). Practice and Research Together (PART; www.partontario.org) is
an Ontario consortium of 45 child welfare organizations whose mandate
is to disseminate research to its member agencies, which include
85% of the local child welfare organizations in the province. Each
member pays an annual membership-fee that is based on its size
(Dill & Shera, 2011). A key factor in PART's success has been its ability
to link its program offerings (i.e., webinars, literature reviews, conferences,
and publications) to issues of real-world relevance to child
welfare practitioners and senior leaders. A central and highly anticipated
program offering is PART's annual conference (learning
event). These conferences bring evidence to bear on practice in priority
areas in child welfare.
On May 31 and June 1 and 2, 2011, PART, in collaboration with the
Centre for Research on Educational and Community Services (CRECS)
at the University of Ottawa, co-hosted an international conference in
Ottawa that was focused on improving the educational achievement
of young people in out-of-home care (hereafter, in care). Speakers
from five countries – Canada, USA, Germany, Sweden, and UK – presented
the results of their research at the conference. The speakers
addressed three main topic areas: the disadvantaged socio-political
status of young people in care, many of whom do not complete secondary
or post-secondary education; innovative interventions to improve
their educational outcomes; and the effectiveness of tutoring,
which is the most common educational intervention for young people
in care.

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The cyclical properties of the Baltic Dry Index (BDI) and their implications for forecasting performance are investigated. We find that changes in the BDI can lead to permanent shocks to trade of major exporting economies. In our forecasting exercise, we show that commodities and trigonometric regression can lead to improved predictions and then use our forecasting results to perform an investment exercise and to show how they can be used for improved risk management in the freight sector.

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Background Very few studies on human exposure to allergenic pollen have been conducted using direct methods, with background concentrations measured at city center monitoring stations typically taken as a proxy for exposure despite the inhomogeneous nature of atmospheric pollen concentrations. A 2003 World Health Organization report highlighted the need for an improved understanding of the relation between monitoring station data and actual exposure. Objective To investigate the relation between grass pollen dose and background concentrations measured at a monitoring station, to assess the fidelity of monitoring station data as a qualitative proxy for dose, and to evaluate the ratio of dose rate to background concentration. Methods Grass pollen dose data were collected in Aarhus, Denmark, in an area where grass pollen sources were prevalent, using Nasal Air Samplers. Sample collection lasted for approximately 25 to 30 minutes and was performed at 2-hour intervals from noon to midevening under moderate exercise by 2 individuals. Results A median ratio of dose rate to background concentration of 0.018 was recorded, with higher ratio values frequently occurring at 12 to 2 pm, the time of day when grass species likely to be present in the area are expected to flower. From 4 to 8 pm, dose rate and background concentration data were found to be strongly and significantly correlated (rs = 0.81). Averaged dose rate and background concentration data showed opposing temporal trends. Conclusion Where local emissions are not a factor, background concentration data constitute a good quantitative proxy for inhaled dose. The present ratio of dose rate to background concentration may aid the study of dose–response relations.