8,517 research outputs found
The prevalence of medical reasons for non-participation in the Scottish breast and bowel cancer screening programmes
Objective: Increasing uptake of cancer screening is a priority for health systems internationally, however, some patients may not attend because they are undergoing active treatment for the cancer of interest or have other medical reasons that mean participation would be inappropriate. This study aims to quantify the proportion of non-participants who have a medical reason for not attending cancer screening.<p></p>
Methods: Medical reasons for not participating in breast and bowel screening were defined a priori on the basis of a literature review and expert opinion. The notes of 700 patients at two GP practices in Scotland were reviewed, to ascertain the prevalence of medical reasons amongst non-participants. Simple proportions and confidence intervals were calculated.<p></p>
Results: 17.4% of breast and 2.3% of bowel screening non-participants had a medical reason to not participate. The two most common reasons were previous breast cancer follow up (8.86%) and recent mammogram (6.57%).<p></p>
Conclusion: These patients may not benefit from screening while also being distressed by receiving an invitation. This issue also makes accurate monitoring and target-setting for improving uptake difficult. Further work is needed to estimate robustly the extent to which medical reasons account for screening non-participation in a larger population.<p></p>
Optical Polarization of 52 Radio-Loud QSOs and BL Lac Objects
Polarization measurements are presented for 52 radio-loud QSOs and BL Lac
objects. For 9 highly polarized (p >3%) AGN, these are the first published
polarization measurements. Of these 9, 7 are highly-polarized QSOs (HPQs), one
is a BL Lac object and another is a likely BL Lac object. Polarization
variability is confirmed for some of these new and previously known
highly-polarized AGN. While 6 of the HPQs have flat radio spectra are almost
certainly blazars, PKS 1452-217 is probably a new member of the rare class of
radio-loud QSOs that show high polarization by scattering, and is therefore
important for testing orientation Unified Schemes. In competition for the
highest redshift HPQ are the well-observed QSO PKS 0438-43 at z = 2.85, with
maximum p = 4.7%, and PKS 0046-315 at z = 2.72, for which we find p = 13%.Comment: 6 pages. Astronomical Journal, in pres
Elementary Quantum Mechanics in a Space-time Lattice
Studies of quantum fields and gravity suggest the existence of a minimal
length, such as Planck length \cite{Floratos,Kempf}. It is natural to ask how
the existence of a minimal length may modify the results in elementary quantum
mechanics (QM) problems familiar to us \cite{Gasiorowicz}. In this paper we
address a simple problem from elementary non-relativistic quantum mechanics,
called "particle in a box", where the usual continuum (1+1)-space-time is
supplanted by a space-time lattice. Our lattice consists of a grid of
rectangles, where , the lattice
parameter, is a fundamental length (say Planck length) and, we take to
be equal to . The corresponding Schrodinger equation becomes a
difference equation, the solution of which yields the -eigenfunctions and
-eigenvalues of the energy operator as a function of . The
-eigenfunctions form an orthonormal set and both -eigenfunctions and
-eigenvalues reduce to continuum solutions as
The corrections to eigenvalues because of the assumed lattice is shown to be
We then compute the uncertainties in position and momentum,
for the box problem and study the consequent modification
of Heisenberg uncertainty relation due to the assumption of space-time lattice,
in contrast to modifications suggested by other investigations such as
\cite{Floratos}
GPAQ-R: development and psychometric properties of a version of the general practice assessment questionnaire for use for revalidation by general practitioners in the UK.
BACKGROUND: The General Practice Assessment Questionnaire (GPAQ) has been widely used to assess patient experience in general practice in the UK since 2004. In 2013, new regulations were introduced by the General Medical Council (GMC) requiring UK doctors to undertake periodic revalidation, which includes assessment of patient experience for individual doctors. We describe the development of a new version of GPAQ - GPAQ-R which addresses the GMC's requirements for revalidation as well as additional NHS requirements for surveys that GPs may need to carry out in their own practices. METHODS: Questionnaires were given out by doctors or practice staff after routine consultations in line with the guidance given by the General Medical Council for surveys to be used for revalidation. Data analysis and practice reports were provided independently. RESULTS: Data were analysed for questionnaires from 7258 patients relating to 164 GPs in 29 general practices. Levels of missing data were generally low (typically 4.5-6%). The number of returned questionnaires required to achieve reliability of 0.7 were around 35 for individual doctor communication items and 29 for a composite score based on doctor communication items. This suggests that the responses to GPAQ-R had similar reliability to the GMC's own questionnaire and we recommend 30 completed GPAQ-R questionnaires are sufficient for revalidation purposes. However, where an initial screen raises concern, the survey might be repeated with 50 completed questionnaires in order to increase reliability. CONCLUSIONS: GPAQ-R is a development of a well-established patient experience questionnaire used in general practice in the UK since 2004. This new version can be recommended for use in order to meet the UK General Medical Council's requirements for surveys to be used in revalidation of doctors. It also meets the needs of GPs to ask about patient experience relating to aspects of practice care that are not specific to individual general practitioners (e.g. receptionists, telephone access) which meet other survey requirements of the National Health Service in England. Use of GPAQ-R has the potential to reduce the number of surveys that GPs need to carry out in their practices to meet the various regulatory requirements which they face
Quantifying inherent predictability and spatial synchrony in the aphid vector Myzus persicae - field-scale patterns of abundance and regional forecasting error in the UK
BACKGROUND
Sugar beet is threatened by virus yellows, a disease complex vectored by aphids that reduces sugar content. We present an analysis of Myzus persicae population dynamics with and without neonicotinoid seed treatment. We use six yearsâ yellow water trap and field-collected aphid data and two decades of 12.2 m suction-trap aphid migration data. We investigate both spatial synchrony and forecasting error to understand the structure and spatial scale of field counts and why forecasting aphid migrants lacks accuracy. Our aim is to derive statistical parameters to inform regionwide pest management strategies.
RESULTS
Spatial synchrony, indicating the coincident change in counts over time across the region, is rarely present and is best described as stochastic. Uniquely, early season field populations in 2019, did show spatial synchrony to 90 km compared to the overall average weekly correlation length of 23 km. However, 70% of the time series were spatially heterogenous, indicating patchy between-field dynamics. Field counts lacked the same seasonal trend and did not peak in the same week. Forecasts tended to under-predict mid-season log10 counts. A strongly negative correlation between forecasting error and the proportion of zeros was shown.
CONCLUSION
Field populations are unpredictable and stochastic, regardless of neonicotinoid seed treatment. This outcome presents a problem for decision-support that cannot usefully provide a single regionwide solution. Weighted permutation entropy inferred that M. persicae 12.2 m suction-trap time series had moderate to low intrinsic predictability. Early warning using a migration model tended to predict counts at lower levels than observed
DFR Perturbative Quantum Field theory on Quantum Space Time, and Wick Reduction
We discuss the perturbative approach a` la Dyson to a quantum field theory
with nonlocal self-interaction :phi*...*phi:, according to Doplicher,
Fredenhagen and Roberts (DFR). In particular, we show that the Wick reduction
of non locally time--ordered products of Wick monomials can be performed as
usual, and we discuss a very simple Dyson diagram.Comment: 15 pages, pdf has active hyperlinks. To appear in the proceedings of
the conference on "Rigorous quantum Field Theory", held at Saclay on July
19-21, 2004, on the occasion of Jacques Bros' 70th birthda
The regulated four parameter one dimensional point interaction
The general four parameter point interaction in one dimensional quantum
mechanics is regulated. It allows the exact solution, but not the perturbative
one. We conjecture that this is due to the interaction not being asymptotically
free. We then propose a different breakup of unperturbed theory and
interaction, which now is asymptotically free but leads to the same physics.
The corresponding regulated potential can be solved both exactly and
perturbatively, in agreement with the conjecture.Comment: 17 pages, no figures, Tex fil
Black hole and the adiabatic phase
An open system consisting of a scalar field bound to a Kerr black hole whose
mass () and specific angular momentum () are slowly (adiabatically)
perturbed is considered. The adiabatically induced phase and the conditions for
the validity of the adiabatic approximation are obtained. The effect of closed
cycles in parameter space (, plane) on the energy levels of both stable
and unstable scalar field bound states, together with other quantities of
interest, is illustrated. Lastly it is noted that the black hole wavefunction
will acquire an equal and opposite phase to that of matter thus leading to a
change of its effective action (entropy).Comment: Plain TeX, 12 page
Optical and Radio monitoring of S5 1803+74
The optical (BVRI) and radio (8.4 GHz) light curves of S5 1803+784 on a time
span of nearly 6 years are presented and discussed. The optical light curve
showed an overall variation greater than 3 mag, and the largest changes occured
in three strong flares. No periodicity was found in the light curve on time
scales up to a year. The variability in the radio band is very different, and
shows moderate oscillations around an average constant flux density rather than
relevant flares, with a maximum amplitude of 30%, without a simultaneous
correspondence between optical and radio luminosity. The optical spectral
energy distribution was always well fitted by a power law. The spectral index
shows small variations and there is indication of a positive correlation with
the source luminosity. Possible explanations of the source behaviour are
discussed in the framework of current models.Comment: 25 pages, 12 figure
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