19,252 research outputs found
Maths for Biosciences: towards developing an innovative e-learning resource for post GCSE students.
Qualitative study of pilot payment aimed at increasing general practitioners' antismoking advice to smokers
OBJECTIVES: To elicit general practitioners' and practice nurses' accounts of changes in their clinical practice or practice organisation made to claim a pilot health promotion payment. To describe attitudes towards the piloted and previous health promotion payments.
DESIGN: Qualitative, semistructured interview study.
SETTING: 13 general practices in Leicester.
PARTICIPANTS: 18 general practitioners and 13 practice nurses.
RESULTS: Health professionals did not report substantially changing their clinical practice to claim the new payments and made only minimal changes in practice organisation. The new health promotion payment did not overcome general practitioners' resistance towards raising the issue of smoking when they felt that doing so could cause confrontation with patients. General practitioners who made the largest number of claims altered the way in which they recorded patients' smoking status rather than raising the topic of smoking more frequently with patients. Participants had strong negative views on die new payment, feeling it would also be viewed negatively by patients. They were, however, more positive about health promotion payments that rewarded "extra" effort-for example, setting up practice based smoking cessation clinics.
CONCLUSIONS: General practitioners and practice nurses were negative about a new health promotion payment, despite agreeing to pilot it. Health promotion payments do not automatically generate effective health promotion activity, and policymakers should consider careful piloting and evaluation of future changes in health promotion payments
Hypervelocity impact microfoil perforations in the LEO space environment (LDEF, MAP AO-023 experiment)
The Microabrasion Foil Experiment comprises arrays of frames, each supporting two layers of closely spaced metallic foils and a back-stop plate. The arrays, deploying aluminum and brass foil ranging from 1.5 to some 30 microns were exposed for 5.78 years on NASA's LDEF at a mean altitude of 458 km. They were deployed on the North, South, East, West, and Space pointing faces; results presented comprise the perforation rates for each location as a function of foil thickness. Initial results refer primarily to aluminum of 5 microns thickness or greater. This penetration distribution, comprising 2,342 perforations in total, shows significantly differing characteristics for each detector face. The anisotropy confirms, incorporating the dynamics of particulate orbital mechanics, the dominance of incorporating extraterrestrial particulates penetrating thicknesses greater than 20 microns in Al foil, yielding fluxes compatible with hyperbolic geocentric velocities. For thinner foils, a disproportionate increase in flux of particles on the East, North, and South faces shows the presence of orbital particulates which exceed the extraterrestrial component perforation rate at 5 micron foil thickness by a factor of approx. 4
Recurrence rates for SIDS - the importance of risk stratification
Objective:
To investigate the importance of stratification by risk factors in computing the probability of a second SIDS in a family.
Design: Simulation Study
Background:
The fact that a baby dies suddenly and unexpectedly means that there is a raised probability that the baby’s family have risk factors associated with Sudden Infant Death Syndrome (SIDS). Thus one cannot consider the risk of a subsequent death to be that of the general population. The Confidential Enquiry into Stillbirths and Deaths in Infancy (CESDI)6 identified three major social risk factors: smoking, age1, and unemployed/unwaged as major risk factors. It gave estimates of risk for families with different numbers of these risk factors. We investigate whether it is reasonable to assume that, conditional on these risk factors, the risk of a second event is independent of the risk of the first and as a consequence one can square the risks to get the risk of two SIDS in a family. We have used CESDI data to estimate the probability of a second SID in a family under different plausible scenarios of the prevalence of the risk factors. We have applied the model to make predictions in the Care of Next Infant (CONI) study7.
Results:
The model gave plausible predictions. The CONI study observed 18 second SIDS. Our model predicted 14 (95% prediction interval 7 to 21).
Conclusion:
When considering the risk of a subsequent SIDS in a family one should always take into account the known risk factors. If all risks have been identified, then conditional on these risks, the risk of two events is the product of the individual risks However for a given family we cannot quantify the magnitude of the increased risk because of other possible risk factors not accounted for in the model
Defining Landscape Resistance Values in Least-Cost Connectivity Models for the Invasive Grey Squirrel: A Comparison of Approaches Using Expert-Opinion and Habitat Suitability Modelling
Least-cost models are widely used to study the functional connectivity of habitat within a varied landscape matrix. A critical step in the process is identifying resistance values for each land cover based upon the facilitating or impeding impact on species movement. Ideally resistance values would be parameterised with empirical data, but due to a shortage of such information, expert-opinion is often used. However, the use of expert-opinion is seen as subjective, human-centric and unreliable. This study derived resistance values from grey squirrel habitat suitability models (HSM) in order to compare the utility and validity of this approach with more traditional, expert-led methods. Models were built and tested with MaxEnt, using squirrel presence records and a categorical land cover map for Cumbria, UK. Predictions on the likelihood of squirrel occurrence within each land cover type were inverted, providing resistance values which were used to parameterise a leastcost model. The resulting habitat networks were measured and compared to those derived from a least-cost model built with previously collated information from experts. The expert-derived and HSM-inferred least-cost networks differ in precision. The HSM-informed networks were smaller and more fragmented because of the higher resistance values attributed to most habitats. These results are discussed in relation to the applicability of both approaches for conservation and management objectives, providing guidance to researchers and practitioners attempting to apply and interpret a leastcost approach to mapping ecological networks.This project was funded by the Forestry Commission GB and the National School of Forestry at the University of Cumbria. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Dynamical symmetry breaking and the Nambu-Goldstone theorem in the Gaussian wave functional approximation
We analyze the group-theoretical ramifications of the Nambu-Goldstone [NG]
theorem in the self-consistent relativistic variational Gaussian wave
functional approximation to spinless field theories. In an illustrative example
we show how the Nambu-Goldstone theorem would work in the O(N) symmetric
scalar field theory, if the residual symmetry of the vacuum were
lesser than O(N-1), e.g. if the vacuum were O(N-2), or O(N-3),... symmetric.
[This does not imply that any of the "lesser" vacua is actually the absolute
energy minimum: stability analysis has not been done.] The requisite number of
NG bosons would be (2N - 3), or (3N - 6), ... respectively, which may exceed N,
the number of elementary fields in the Lagrangian. We show how the requisite
new NG bosons would appear even in channels that do not carry the same quantum
numbers as one of N "elementary particles" (scalar field quanta, or
Castillejo-Dalitz-Dyson [CDD] poles) in the Lagrangian, i.e. in those "flavour"
channels that have no CDD poles. The corresponding Nambu-Goldstone bosons are
composites (bound states) of pairs of massive elementary (CDD) scalar fields
excitations. As a nontrivial example of this method we apply it to the
physically more interesting 't Hooft model (an extended
bosonic linear model with four scalar and four pseudoscalar fields),
with spontaneously and explicitly broken chiral symmetry.Comment: 17 pages, no figure
The Effect of Guardianship on Estate Plans
One responds to the certainty of death with dread and respect, and one lays plans for the event. Few, however, admit or even think of the possibility that they may become incompetent in their old age; hence, provision is rarely made for this possibility in estate plans. The increased longevity resulting from the recent rapid strides in medicine has as its corollary an increase both in the number of persons who become incompetent before death and the duration of their affliction. This poses a challenge to estate planners and the law of guardianship.
Today the guardianship of the person of an incompetent does not present the law with many new problems; this comment, therefore, will be concerned exclusively with the problems associated with the guardianship of an incompetent\u27s estate
Density distributions of superheavy nuclei
We employed the Skyrme-Hartree-Fock model to investigate the density
distributions and their dependence on nuclear shapes and isospins in the
superheavy mass region. Different Skyrme forces were used for the calculations
with a special comparison to the experimental data in Pb. The
ground-state deformations, nuclear radii, neutron skin thicknesses and
-decay energies were also calculated. Density distributions were
discussed with the calculations of single-particle wavefunctions and shell
fillings. Calculations show that deformations have considerable effects on the
density distributions, with a detailed discussion on the 120 nucleus.
Earlier predictions of remarkably low central density are not supported when
deformation is allowed for.Comment: 7 pages, 10 figure
QCD Corrections to t anti-b H^- Associated Production in e^+ e^- Annihilation
We calculate the QCD corrections to the cross section of e^+ e^- -> t anti-b
H^- and its charge-conjugate counterpart within the minimal supersymmetric
extension of the Standard Model. This process is particularly important if m_t
b H^+ and e^+ e^- -> H^+ H^- are
not allowed kinematically. Large logarithmic corrections that arise in the
on-mass-shell scheme of quark mass renormalization, especially from the t
anti-b H^- Yukawa coupling for large values of tan(beta), are resummed by
adopting the modified minimal-subtraction scheme, so that the convergence
behavior of the perturbative expansion is improved. The inclusion of the QCD
corrections leads to a significant reduction of the theoretical uncertainties
due to scheme and scale dependences.Comment: 21 pages (Latex), 8 figures (Postscript); detailed discussion of
scheme and scale dependences adde
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