1,317 research outputs found
Factors contributing to the time taken to consult with symptoms of lung cancer: a cross-sectional study
<b>Objectives</b>: To determine what factors are associated with the time people take to consult with symptoms of lung cancer, with a focus on those from rural and socially deprived areas.
<b>Methods</b>: A cross-sectional quantitative interview survey was performed of 360 patients with newly diagnosed primary lung cancer in three Scottish hospitals (two in Glasgow, one in NE Scotland). Supplementary data were obtained from medical case notes. The main outcome measures were the number of days from (1) the date participant defined first symptom until date of presentation to a medical practitioner; and (2) the date of earliest symptom from a symptom checklist (derived from clinical guidelines) until date of presentation to a medical practitioner.
<b>Results</b>: 179 participants (50%) had symptoms for more than 14 weeks before presenting to a medical practitioner (median 99 days; interquartile range 31–381). 270 participants (75%) had unrecognised symptoms of lung cancer. There were no significant differences in time taken to consult with symptoms of lung cancer between rural and/or deprived participants compared with urban and/or affluent participants. Factors independently associated with increased time before consulting about symptoms were living alone, a history of chronic obstructive pulmonary disease (COPD) and longer pack years of smoking. Haemoptysis, new onset of shortness of breath, cough and loss of appetite were significantly associated with earlier consulting, as were a history of chest infection and renal failure.
<b>Conclusion</b>: For many people with lung cancer, regardless of location and socioeconomic status, the time between symptom onset and consultation was long enough to plausibly affect prognosis. Long-term smokers, those with COPD and/or those living alone are at particular risk of taking longer to consult with symptoms of lung cancer and practitioners should be alert to this
Nanoengineering Carbon Allotropes from Graphene
Monolithic structures can be built into graphene by the addition and
subsequent re-arrangement of carbon atoms. To this end, ad-dimers of carbon are
a particularly attractive building block because a number of emerging
technologies offer the promise of precisely placing them on carbon surfaces. In
concert with the more common Stone-Wales defect, repeating patterns can be
introduced to create as yet unrealized materials. The idea of building such
allotropes out of defects is new, and we demonstrate the technique by
constructing two-dimensional carbon allotropes known as haeckelite. We then
extend the idea to create a new class of membranic carbon allotropes that we
call \emph{dimerite}, composed exclusively of ad-dimer defects.Comment: 5 pages, 5 figure
Effect of initial correlations on short-time decoherence
We study the effect of initial correlations on the short-time decoherence of
a particle linearly coupled to a bath of harmonic oscillators. We analytically
evaluate the attenuation coefficient of a Schroedinger cat state both for a
free and a harmonically bound particle, with and without initial thermal
correlations between the particle and the bath. While short-time decoherence
appears to be independent of the system in the absence of initial correlations,
we find on the contrary that, for initial thermal correlations, decoherence
becomes system dependent even for times much shorter than the characteristic
time of the system. The temperature behavior of this system dependence is
discussed.Comment: 7 pages, 1 figur
Cut Vertices and Semi-Inclusive Deep Inelastic Processes
Cut vertices, a generalization of matrix elements of local operators, are
revisited, and an expansion in terms of minimally subtracted cut vertices is
formulated. An extension of the formalism to deal with semi-inclusive deep
inelastic processes in the target fragmentation region is explicitly
constructed. The problem of factorization is discussed in detail.Comment: LaTex2e, 24 pages including 17 postscript figure
Magnetoresistance of Two-Dimensional Fermions in a Random Magnetic Field
We perform a semiclassical calculation of the magnetoresistance of spinless
two-dimensional fermions in a long-range correlated random magnetic field. In
the regime relevant for the problem of the half filled Landau level the
perturbative Born approximation fails and we develop a new method of solving
the Boltzmann equation beyond the relaxation time approximation. In absence of
interactions, electron density modulations, in-plane fields, and Fermi surface
anisotropy we obtain a quadratic negative magnetoresistance in the weak field
limit.Comment: 12 pages, Latex, no figures, Nordita repor
Three point SUSY Ward identities without Ghosts
We utilise a non-local gauge transform which renders the entire action of
SUSY QED invariant and respects the SUSY algebra modulo the gauge-fixing
condition, to derive two- and three-point ghost-free SUSY Ward identities in
SUSY QED. We use the cluster decomposition principle to find the Green's
function Ward identities and then takes linear combinations of the latter to
derive identities for the proper functions.Comment: 20 pages, no figures, typos correcte
The Quark-Hadron Phase Transition, QCD Lattice Calculations and Inhomogeneous Big-Bang Nucleosynthesis
We review recent lattice QCD results for the surface tension at the finite
temperature quark-hadron phase transition and discuss their implications on the
possible scale of inhomogeneities. In the quenched approximation the average
distance between nucleating centers is smaller than the diffusion length of a
protron, so that inhomogeneities are washed out by the time nucleosynthesis
sets in. Consequently the baryon density fluctuations formed by a QCD phase
transition in the early universe cannot significantly affect standard big-bang
nucleosynthesis calculations and certainly cannot allow baryons to close the
universe. At present lattice results are inconclusive when dynamical fermions
are included.Comment: 8 pages, LaTe
Electron energy loss and induced photon emission in photonic crystals
The interaction of a fast electron with a photonic crystal is investigated by
solving the Maxwell equations exactly for the external field provided by the
electron in the presence of the crystal. The energy loss is obtained from the
retarding force exerted on the electron by the induced electric field. The
features of the energy loss spectra are shown to be related to the photonic
band structure of the crystal. Two different regimes are discussed: for small
lattice constants relative to the wavelength of the associated electron
excitations , an effective medium theory can be used to describe the
material; however, for the photonic band structure plays an
important role. Special attention is paid to the frequency gap regions in the
latter case.Comment: 12 pages, 7 figure
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