13,547 research outputs found
Waves in a hot uniaxial plasma excited by a current source
The fields excited by a short dipole antenna in a hot uniaxially anisotropic plasma (B_0→∞) have been studied. When ω<ω_p, the dipole effectively excites two propagating waves, a slow wave and a fast wave, inside a cone of half‐cone angle sin^(−1)(ω/ω_p). Inside the cone a characteristic interference structure in the angular distribution of the fields is noted. Outside the cone fields fall off exponentially. The appearance of the cone and the characteristic interference structure in the field is useful from the viewpoint of laboratory diagnostics
R-matrices and Tensor Product Graph Method
A systematic method for constructing trigonometric R-matrices corresponding
to the (multiplicity-free) tensor product of any two affinizable
representations of a quantum algebra or superalgebra has been developed by the
Brisbane group and its collaborators. This method has been referred to as the
Tensor Product Graph Method. Here we describe applications of this method to
untwisted and twisted quantum affine superalgebras.Comment: LaTex 7 pages. Contribution to the APCTP-Nankai Joint Symposium on
"Lattice Statistics and Mathematical Physics", 8-10 October 2001, Tianjin,
Chin
Disk M Dwarf Luminosity Function From HST Star Counts
We study a sample of 257 Galactic disk M dwarfs (8<M_V<18.5) found in images
obtained using HST. These include 192 stars in 22 fields imaged with the
repaired WFC2 with mean limiting mag I=23.7 and 65 stars in 162 fields imaged
with the pre-repair Planetary Camera with mean limiting mag V=21.3. We find
that the disk luminosity function (LF) drops sharply for M_V>12 (M<0.25 \ms),
decreasing by a factor \gsim 3 by M_V~14 (M~0.14\ms). This decrease in the LF
is in good agreement with the ground-based photometric study of nearby stars by
Stobie et al. (1989), and in mild conflict with the most recent LF measurements
based on local parallax stars by Reid et al. (1995). The local LF of the faint
Galactic disk stars can be transformed into a local mass function using an
empirical mass-M_V relation. The mass function can be represented analytically
over the mass range 0.1\ms<M<1.6\ms by \log(\phi)=-1.35-1.34\log(M/\ms)-1.85
[\log(M/\ms)]^2 where \phi is the number density per logarithmic unit of mass.
The total column density of M stars is only \Sigma_M=11.8\pm 1.8\ms\pc^{-2},
implying a total `observed' disk column density of \Sigma_\obs~=39\ms\pc^{-2},
lower than previously believed, and also lower than all estimates with which we
are familiar of the dynamically inferred mass of the disk. The measured scale
length for the M-star disk is 3.0\pm 0.4 kpc. The optical depth to microlensing
toward the LMC by the observed stars in the Milky Way disk is \tau~1x10^{-8},
compared to the observed optical depth found in ongoing experiments \tau_\obs~
10^{-7}. The M-stars show evidence for a population with characteristics
intermediate between thin disk and spheroid populations. Approximating what may
be a continuum of populations by two separate component, we find characteristic
exponential scale heights of ~210 pc and ~740 pc.Comment: 30 pages, uuencoded postscript, includes 3 figures, 2 table
Casimir invariants and characteristic identities for
A full set of (higher order) Casimir invariants for the Lie algebra
is constructed and shown to be well defined in the category
generated by the highest weight (unitarizable) irreducible
representations with only a finite number of non-zero weight components.
Moreover the eigenvalues of these Casimir invariants are determined explicitly
in terms of the highest weight. Characteristic identities satisfied by certain
(infinite) matrices with entries from are also determined and
generalize those previously obtained for by Bracken and Green.Comment: 10 pages, PlainTe
Infrared Line Emission from Planetary Nebulae. I - General Theory
General theory of infrared line emission from planetary nebul
Recommended from our members
Interventions to improve hand hygiene compliance in patient care
Background
Health care‐associated infection is a major cause of morbidity and mortality. Hand hygiene is regarded as an effective preventive measure. This is an update of a previously published review.
Objectives
To assess the short‐ and long‐term success of strategies to improve compliance to recommendations for hand hygiene, and to determine whether an increase in hand hygiene compliance can reduce rates of health care‐associated infection.
Search methods
We conducted electronic searches of the Cochrane Register of Controlled Trials, PubMed, Embase, and CINAHL. We conducted the searches from November 2009 to October 2016.
Selection criteria
We included randomised trials, non‐randomised trials, controlled before‐after studies, and interrupted time series analyses (ITS) that evaluated any intervention to improve compliance with hand hygiene using soap and water or alcohol‐based hand rub (ABHR), or both.
Data collection and analysis
Two review authors independently screened citations for inclusion, extracted data, and assessed risks of bias for each included study. Meta‐analysis was not possible, as there was substantial heterogeneity across studies. We assessed the certainty of evidence using the GRADE approach and present the results narratively in a 'Summary of findings' table.
Main results
This review includes 26 studies: 14 randomised trials, two non‐randomised trials and 10 ITS studies. Most studies were conducted in hospitals or long‐term care facilities in different countries, and collected data from a variety of healthcare workers. Fourteen studies assessed the success of different combinations of strategies recommended by the World Health Organization (WHO) to improve hand hygiene compliance. Strategies consisted of the following: increasing the availability of ABHR, different types of education for staff, reminders (written and verbal), different types of performance feedback, administrative support, and staff involvement. Six studies assessed different types of performance feedback, two studies evaluated education, three studies evaluated cues such as signs or scent, and one study assessed placement of ABHR. Observed hand hygiene compliance was measured in all but three studies which reported product usage. Eight studies also reported either infection or colonisation rates. All studies had two or more sources of high or unclear risks of bias, most often associated with blinding or independence of the intervention.
Multimodal interventions that include some but not all strategies recommended in the WHO guidelines may slightly improve hand hygiene compliance (five studies; 56 centres) and may slightly reduce infection rates (three studies; 34 centres), low certainty of evidence for both outcomes.
Multimodal interventions that include all strategies recommended in the WHO guidelines may slightly reduce colonisation rates (one study; 167 centres; low certainty of evidence). It is unclear whether the intervention improves hand hygiene compliance (five studies; 184 centres) or reduces infection (two studies; 16 centres) because the certainty of this evidence is very low.
Multimodal interventions that contain all strategies recommended in the WHO guidelines plus additional strategies may slightly improve hand hygiene compliance (six studies; 15 centres; low certainty of evidence). It is unclear whether this intervention reduces infection rates (one study; one centre; very low certainty of evidence).
Performance feedback may improve hand hygiene compliance (six studies; 21 centres; low certainty of evidence). This intervention probably slightly reduces infection (one study; one centre) and colonisation rates (one study; one centre) based on moderate certainty of evidence.
Education may improve hand hygiene compliance (two studies; two centres), low certainty of evidence.
Cues such as signs or scent may slightly improve hand hygiene compliance (three studies; three centres), low certainty of evidence.
Placement of ABHR close to point of use probably slightly improves hand hygiene compliance (one study; one centre), moderate certainty of evidence.
Authors' conclusions
With the identified variability in certainty of evidence, interventions, and methods, there remains an urgent need to undertake methodologically robust research to explore the effectiveness of multimodal versus simpler interventions to increase hand hygiene compliance, and to identify which components of multimodal interventions or combinations of strategies are most effective in a particular context
A New Photometric Model of the Galactic Bar using Red Clump Giants
We present a study of the luminosity density distribution of the Galactic bar
using number counts of red clump giants (RCGs) from the OGLE-III survey. The
data were recently published by Nataf et al. (2013) for 9019 fields towards the
bulge and have RC stars over a viewing area of . The data include the number counts, mean distance modulus
(), dispersion in and full error matrix, from which we fit the data
with several tri-axial parametric models. We use the Markov Chain Monte Carlo
(MCMC) method to explore the parameter space and find that the best-fit model
is the model, with the distance to the GC is 8.13 kpc, the ratio of
semi-major and semi-minor bar axis scale lengths in the Galactic plane
, and vertical bar scale length , is (close to being prolate). The scale length of the stellar
density profile along the bar's major axis is 0.67 kpc and has an angle
of , slightly larger than the value obtained from a similar study
based on OGLE-II data. The number of estimated RC stars within the field of
view is , which is systematically lower than the observed
value. We subtract the smooth parametric model from the observed counts and
find that the residuals are consistent with the presence of an X-shaped
structure in the Galactic centre, the excess to the estimated mass content is
. We estimate the total mass of the bar is . Our results can be used as a key ingredient to construct new density
models of the Milky Way and will have implications on the predictions of the
optical depth to gravitational microlensing and the patterns of hydrodynamical
gas flow in the Milky Way.Comment: 15 pages, 6 figures, 4 tables. MNRAS accepte
- …