4,523 research outputs found
Evidence for prevention and screening: recommendations in adults.
A growing body of evidence supports preventive interventions in asymptomatic adults. Primary prevention, which includes counselling (in particular for smoking cessation) and review of immunisation status, has been shown to be more cost-effective than secondary prevention. Evidence supports screening for hypertension, hyperlipidaemia, cervical cancer, colorectal cancer, breast cancer and obesity. Screening for lung, pancreatic and ovarian cancer has no effect on outcome and should not be performed. Controversial preventive interventions include general screening for diabetes mellitus, thyroid disorders and prostate cancer. Physicians should be aware of a possible hidden agenda in patients presenting for a checkup
Equation of motion for a domain wall coupled to gravitational field
The equation of motion for a domain wall coupled to gravitational field is
derived from the Nambu-Goto action. The domain wall is treated as a source of
gravitational field. The perturbed equation is also obtained with gravitational
back reaction on the wall motion taken into account. For general spherically
symmetric background case, the equation is expressed in terms of the
gauge-invariant variables.Comment: 13 pages, latex, no figures, uses REVTe
An Observational Test of Two-field Inflation
We study adiabatic and isocurvature perturbation spectra produced by a period
of cosmological inflation driven by two scalar fields. We show that there
exists a model-independent consistency condition for all two-field models of
slow-roll inflation, despite allowing for model-dependent linear processing of
curvature and isocurvature perturbations during and after inflation on
super-horizon scales. The scale-dependence of all spectra are determined solely
in terms of slow-roll parameters during inflation and the dimensionless
cross-correlation between curvature and isocurvature perturbations. We present
additional model-dependent consistency relations that may be derived in
specific two-field models, such as the curvaton scenario.Comment: 6 pages, latex with revtex, no figures; v2, minor changes, to appear
in Physical Review
Structural and magnetic properties of E-Fe_{1-x}Co_xSi thin films deposited via pulsed laser deposition
We report pulsed laser deposition synthesis and characterization of
polycrystalline Fe1-xCox Si thin films on Si (111). X-ray diffraction,
transmission electron, and atomic force microscopies reveal films to be dense,
very smooth, and single phase with a cubic B20 crystal structure.
Ferromagnetism with significant magnetic hysteresis is found for all films
including nominally pure FeSi films in contrast to the very weak paramagnetism
of bulk FeSi. For Fe1-xCoxSi this signifies a change from helimagnetism in
bulk, to ferromagnetism in thin films. These ferromagnetic thin films are
promising as a magnetic-silicide/silicon system for polarized current
production, manipulation, and detection.Comment: 12 pages, 4 figures accepted in the Applied Physics Letter
SO(10) Cosmic Strings and SU(3) Color Cheshire Charge
Certain cosmic strings that occur in GUT models such as can carry a
magnetic flux which acts nontrivially on objects carrying
quantum numbers. We show that such strings are non-Abelian Alice strings
carrying nonlocalizable colored ``Cheshire" charge. We examine claims made in
the literature that strings can have a long-range, topological
Aharonov-Bohm interaction that turns quarks into leptons, and observe that such
a process is impossible. We also discuss flux-flux scattering using a
multi-sheeted formalism.Comment: 37 Pages, 8 Figures (available upon request) phyzzx, iassns-hep-93-6,
itp-sb-93-6
Gravity Waves from Instantons
We perform a first principles computation of the spectrum of gravity waves
produced in open inflationary universes. The background spacetime is taken to
be the continuation of an instanton saddle point of the Euclidean no boundary
path integral. The two-point tensor correlator is computed directly from the
path integral and is shown to be unique and well behaved in the infrared. We
discuss the tensor contribution to the cosmic microwave background anisotropy
and show how it may provide an observational discriminant between different
types of primordial instantons.Comment: 19 pages, RevTex file, including two postscript figure file
Upper Limit on the molecular resonance strengths in the C+C fusion reaction
Carbon burning is a crucial process for a number of important astrophysical
scenarios. The lowest measured energy is around E=2.1 MeV, only
partially overlapping with the energy range of astrophysical interest. The
currently adopted reaction rates are based on an extrapolation which is highly
uncertain because of potential resonances existing in the unmeasured energy
range and the complication of the effective nuclear potential. By comparing the
cross sections of the three carbon isotope fusion reactions,
C+C, C+C and C+C, we have
established an upper limit on the molecular resonance strengths in
C+C fusion reaction. The preliminary results are presented
and the impact on nuclear astrophysics is discussed.Comment: 4 pages, 3 figures, FUSION11 conference proceedin
Optical study of the electronic phase transition of strongly correlated YbInCu_4
Infrared, visible and near-UV reflectivity measurements are used to obtain
conductivity as a function of temperature and frequency in YbInCu_4, which
exhibits an isostructural phase-transition into a mixed-valent phase below
T_v=42 K. In addition to a gradual loss of spectral weight with decreasing
temperature extending up to 1.5 eV, a sharp resonance appears at 0.25 eV in the
mixed-valent phase. This feature can be described in terms of excitations into
the Kondo (Abrikosov-Suhl) resonance, and, like the sudden reduction of
resistivity, provides a direct reflection of the onset of coherence in this
strongly correlated electron system.Comment: 4 pages, 3 figures (to appear in Phys. Rev. B
Bubble wall perturbations coupled with gravitational waves
We study a coupled system of gravitational waves and a domain wall which is
the boundary of a vacuum bubble in de Sitter spacetime. To treat the system, we
use the metric junction formalism of Israel. We show that the dynamical degree
of the bubble wall is lost and the bubble wall can oscillate only while the
gravitational waves go across it. It means that the gravitational backreaction
on the motion of the bubble wall can not be ignored.Comment: 23 pages with 3 eps figure
Thermo-mechanical behaviour of a compacted swelling clay
Compacted unsaturated swelling clay is often considered as a possible buffer
material for deep nuclear waste disposal. An isotropic cell permitting
simultaneous control of suction, temperature and pressure was used to study the
thermo-mechanical behaviour of this clay. Tests were performed at total
suctions ranging from 9 to 110 MPa, temperature from 25 to 80 degrees C,
isotropic pressure from 0.1 to 60 MPa. It was observed that heating at constant
suction and pressure induces either swelling or contraction. The results from
compression tests at constant suction and temperature evidenced that at lower
suction, the yield pressure was lower, the elastic compressibility parameter
and the plastic compressibility parameter were higher. On the other hand, at a
similar suction, the yield pressure was slightly influenced by the temperature;
and the compressibility parameters were insensitive to temperature changes. The
thermal hardening phenomenon was equally evidenced by following a
thermo-mechanical path of loading-heating-cooling-reloading
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