619 research outputs found
Development of nuclear DNA markers to detect hybridization and assess phylogenetic relationships among subspecies of rainbow trout ( Oncorhynchus mykiss) and cutthroat trout (Oncorhynchus clarki)
Place representation in tourist guidebooks - an example from Singapore
Tourist guidebooks provide an important source of information on places. Different guidebooks are written for different types of visitors to better meet their individual travel needs. This is demonstrated through a content analysis of four guidebooks written for Singapore in the early 1980s. Two of the guidebooks represent variations on mainstream, mass travel interests. The third source presents the long-term expatriates perception, while the fourth source presents the alternative or youth tourist view of Singapore. Urban tourism is shown to be multifaceted, allowing for a diversity of travel motivations, experiences, and behavior
Role of correlated two-pion exchange in scattering
A dynamical model for S-- and P--wave correlated (and )
exchange between a kaon and a nucleon is presented, starting from corresponding
amplitudes in the pseudophysical region, which
have been constructed from nucleon, --isobar and hyperon (,
) exchange Born terms and a realistic meson exchange model of the and amplitude. The
contribution in the s--channel is then obtained by performing a dispersion
relation over the unitarity cut. In the --channel, considerable
ambiguities exist, depending on how the dispersion integral is performed. Our
model, supplemented by short range interaction terms, is able to describe
empirical data below pion production threshold in a satisfactory way.Comment: 24 pages, REVTEX, figures available from the author
Unitarity and the Bethe-Salpeter Equation
We investigate the relation between different three-dimensional reductions of
the Bethe-Salpeter equation and the analytic structure of the resultant
amplitudes in the energy plane. This correlation is studied for both the
interaction Lagrangian and the system with -, -,
and -channel pole diagrams as driving terms. We observe that the equal-time
equation, which includes some of the three-body unitarity cuts, gives the best
agreement with the Bethe-Salpeter result. This is followed by other 3-D
approximations that have less of the analytic structure.Comment: 17 pages, 8 figures; RevTeX. Version accepted for publication in
Phys. Rev.
Climate change refugia for the flora and fauna of England
A variety of evidence suggests that species have, in the past, been able to withstand the effects of climatic change in localised environments known as refugia, where specific environmental conditions acted as a buffer against broader-scale climatic changes.
Therefore, an important question for conservation is whether refugia might exist under current and future anthropogenic climate change. If there are areas that are likely to remain relatively climatically stable and so enable species to persist despite climate change making surrounding areas unsuitable, identifying and protecting these places will be an important part of future conservation strategies.
This report is part of a project that is investigating this question. The report was commissioned to identify the characteristics of potential refugia, to investigate evidence for the existence of contemporary refugia by analysing patterns of local persistence and disappearance of over 1000 species across a range of taxa, and to identify sites in England with the potential to function as refugia for different taxonomic groups at a range of spatial scales
BICCO-Net II. Final report to the Biological Impacts of Climate Change Observation Network (BICCO-Net) Steering Group
• BICCO-Net Phase II presents the most comprehensive single assessment of climate change impacts on UK biodiversity to date.
• The results provide a valuable resource for the CCRA 2018, future LWEC report cards, the National Adaptation Programme and other policy-relevant initiatives linked to climate change impacts on biodiversity
Impacts of climate change on national biodiversity population trends
Climate change has had well-documented impacts on the distribution and phenology of species across many taxa, but impacts on species’ abundance, which relates closely to extinction risk and ecosystem function, have not been assessed across taxa. In the most comprehensive multi-taxa comparison to date, we modelled variation in national population indices of 501 mammal, bird, aphid, butterfly and moth species as a function of annual variation in weather variables, which through time allowed us to identify a component of species’ population growth that can be associated with post-1970s climate trends. We found evidence that these climate trends have significantly affected population trends of 15.8% of species, including eight with extreme (> 30% decline per decade) negative trends consistent with detrimental impacts of climate change. The modelled effect of climate change could explain 48% of the significant across-species population decline in moths and 63% of the population increase in winged aphids. The other taxa did not have significant across-species population trends or consistent climate change responses. Population declines in species of conservation concern were linked to both climatic and non-climatic factors respectively accounting for 42 and 58% of the decline. Evident differential impacts of climate change between trophic levels may signal the potential for future ecosystem disruption. Climate change has therefore already driven large-scale population changes of some species, had significant impacts on the overall abundance of some key invertebrate groups and may already have altered biological communities and ecosystems in Great Britain
Adalimumab for non-infectious uveitis: is it cost-effective?
BACKGROUND/AIMS: Uveitis is inflammation inside the eye. Our objective was to assess the cost-effectiveness of adalimumab compared with current practice (immunosuppressants and systemic corticosteroids) in patients with non-infectious intermediate, posterior or panuveitis and to identify areas for future research. METHODS: A Markov model was built to estimate costs and benefits of the interventions. Systematic reviews were performed to identify the available relevant clinical and cost-effectiveness evidence. Data collected in two key randomised controlled trials (VISUAL I and VISUAL II) were used to estimate the interventions' effectiveness compared with the trials' comparator arms (placebo plus limited current practice (LCP)). The analysis was performed from the National Health Service and Personal Social Services perspective. Costs were calculated based on standard UK sources. RESULTS: The estimated incremental cost-effectiveness ratios (ICERs) of adalimumab versus LCP for the base case are £92 600 and £318 075 per quality-adjusted life year (QALY) gained for active and inactive uveitis, respectively. In sensitivity analyses, the ICER varied from £15 579 to £120 653 and £35 642 to £800 775 per QALY for active and inactive uveitis. CONCLUSION: The estimated ICERs of adalimumab versus LCP are above generally accepted thresholds for cost-effectiveness in the UK. Adalimumab may be more cost-effective in patients with active uveitis at greater risk of blindness. However, there is an unmet need for additional primary data to provide more reliable estimates in several important areas, including effectiveness of adalimumab versus current practice (instead of LCP), incidence of long-term blindness, adalimumab effectiveness in avoiding blindness, and rates and time to remission while on adalimumab
Leadership in Improving Schools: A Qualitative Perspective
This article reports early case-study data gathered from 20 schools involved in the ‘Impact of School Leadership on Pupil Outcomes’ project. We present and discuss the perceptions of headteachers and other school leaders regarding leadership factors that directly and indirectly affect pupil outcomes in these improving schools. Included are issues relating to the pivotal role played by the headteacher in setting and communicating a strategic vision for the school; models of distributed leadership; and the building of leadership capacity so as to build a collective responsibility for the improvement of pupil outcomes
Promotion of testa rupture during garden cress germination involves seed compartment-specific expression and activity of pectin methylesterases
Pectin methylesterase (PME) controls the methylesterification status of pectins and thereby determines the biophysical properties of plant cell walls, which are important for tissue growth and weakening processes. We demonstrate here that tissue-specific and spatiotemporal alterations in cell wall pectin methylesterification occur during the germination of garden cress (Lepidium sativum). These cell wall changes are associated with characteristic expression patterns of PME genes and resultant enzyme activities in the key seed compartments CAP (micropylar endosperm) and RAD (radicle plus lower hypocotyl). Transcriptome and quantitative real-time reverse transcription-polymerase chain reaction analysis as well as PME enzyme activity measurements of separated seed compartments, including CAP and RAD, revealed distinct phases during germination. These were associated with hormonal and compartment-specific regulation of PME group 1, PME group 2, and PME inhibitor transcript expression and total PME activity. The regulatory patterns indicated a role for PME activity in testa rupture (TR). Consistent with a role for cell wall pectin methylesterification in TR, treatment of seeds with PME resulted in enhanced testa permeability and promoted TR. Mathematical modeling of transcript expression changes in germinating garden cress and Arabidopsis (Arabidopsis thaliana) seeds suggested that group 2 PMEs make a major contribution to the overall PME activity rather than acting as PME inhibitors. It is concluded that regulated changes in the degree of pectin methylesterification through CAP- and RAD-specific PME and PME inhibitor expression play a crucial role during Brassicaceae seed germination
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