6,032 research outputs found
The Minimal Set of Electroweak Precision Parameters
We present a simple method for analyzing the impact of precision electroweak
data above and below the Z-peak on flavour-conserving heavy new physics. We
find that experiments have probed about ten combinations of new physics
effects, which to a good approximation can be condensed into the effective
oblique parameters Shat, That, Uhat, V, X, W, Y (we prove positivity
constraints W, Y >= 0) and three combinations of quark couplings (including a
distinct parameter for the bottom). We apply our method to generic extra Z'
vectors.Comment: 22 pages, 3 figure
Topical analgesia for acute otitis media
BACKGROUND: Acute otitis media (AOM) is a spontaneously remitting disease of which pain is the most distressing symptom. Antibiotics are now known to have less benefit than previously assumed. Topical pain relief may be a satisfactory intervention for AOM sufferers and encourage clinicians to prescribe fewer antibiotics. OBJECTIVES: To assess the effectiveness of topical analgesia for AOM in adults and children. SEARCH METHODS: For this second update we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), Ovid MEDLINE (2008 to February Week 1 2011), Ovid MEDLINE (InâProcess & Other NonâIndexed Citations 10 February 2011), Ovid EMBASE (2008 to 2011 Week 05), EBSCO CINAHL (2008 to 4 February 2011) and Ovid AMED (2008 to April 2011). SELECTION CRITERIA: Doubleâblind randomised controlled trials (RCTs) or quasiâRCTs comparing an otic preparation with an analgesic effect (excluding antibiotics) versus placebo or an otic preparation with an analgesic effect (excluding antibiotics) versus any other otic preparation with an analgesic effect, in adults or children presenting at primary care settings with AOM without perforation. DATA COLLECTION AND ANALYSIS: Three review authors independently screened studies, assessed trial quality and extracted data. Attempts to obtain additional information from the trial authors of the included trials were unsuccessful. MAIN RESULTS: Five trials including 391 children aged three to 18 years met our criteria. Two studies (117 children) compared anaesthetic ear drops versus placebo immediately at diagnosis. All children received some form of oral pain relief. In all five studies it was clear that ear pain diminishes rapidly for most sufferers. Nevertheless there was a statistically significant difference in the proportion of children achieving a 50% reduction in pain in favour of anaesthetic drops 10 minutes after instillation (risk ratio (RR) 2.13, 95% confidence interval (CI) 1.19 to 3.80) and 30 minutes after instillation (RR 1.43, 95% CI 1.12 to 1.81) on the day AOM was diagnosed but not at 20 minutes (RR 1.24, 95% CI 0.88 to 1.74). Three trials (274 children) compared anaesthetic ear drops with naturopathic herbal ear drops. Naturopathic drops were favoured 15 and 30 minutes after instillation, one to three days after diagnosis, but the differences were not statistically significant. Only one trial looked at adverse reactions and found none. Overall the findings of this review are based on trial evidence that is at low or unclear risk of bias. AUTHORS' CONCLUSIONS: Evidence from five RCTs, only two of which addressed the most relevant question of primary effectiveness, provides limited evidence that ear drops are effective 30 minutes after administration in older children with AOM. Uncertainty exists as to the magnitude of this effect and more highâquality studies are needed
Low-Metallicity Gas Clouds in a Galaxy Proto-Cluster at Redshift 2.38
We present high resolution spectroscopy of a QSO whose sight-line passes
through the halo of a pair of elliptical galaxies at redshift 2.38. This pair
of galaxies probably lies at the center of a galaxy proto-cluster, and is
embedded in a luminous extended Ly-alpha nebula.
The QSO sight-line intersects two small gas clouds within this halo. These
clouds have properties similar to those of high velocity clouds (HVCs) seen in
the halo of the Milky Way. The gas is in a cool (< 2 x 10^4 K) and at least 20%
neutral phase, with metallicities in the range -3.0 < [Fe/H] < -1.1 and neutral
hydrogen column densities of ~10^19.5 /cm^2.
The origin of these clouds is unclear. The presence of low metallicity gas
within this possible proto-cluster implies either that the intra-cluster medium
has not been enriched with metals at this redshift, or the clouds are embedded
within a hot, ionized, metal-rich gas phase.Comment: Accepted to appear in ApJ Letter
Voltage-controlled electron tunnelling from a single self-assembled quantum dot embedded in a two-dimensional-electron-gas-based photovoltaic cell
We perform high-resolution photocurrent (PC) spectroscopy to investigate
resonantly the neutral exciton ground-state (X0) in a single InAs/GaAs
self-assembled quantum dot (QD) embedded in the intrinsic region of an
n-i-Schottky photodiode based on a two-dimensional electron gas (2DEG), which
was formed from a Si delta-doped GaAs layer. Using such a device, a single-QD
PC spectrum of X0 is measured by sweeping the bias-dependent X0 transition
energy through that of a fixed narrow-bandwidth laser via the quantum-confined
Stark effect (QCSE). By repeating such a measurement for a series of laser
energies, a precise relationship between the X0 transition energy and bias
voltage is then obtained. Taking into account power broadening of the X0
absorption peak, this allows for high-resolution measurements of the X0
homogeneous linewidth and, hence, the electron tunnelling rate. The electron
tunnelling rate is measured as a function of the vertical electric field and
described accurately by a theoretical model, yielding information about the
electron confinement energy and QD height. We demonstrate that our devices can
operate as 2DEG-based QD photovoltaic cells and conclude by proposing two
optical spintronic devices that are now feasible.Comment: 34 pages, 11 figure
Effects of Prebiotic and Probiotic Supplementation on Lactase Deficiency and Lactose Intolerance: A Systematic Review of Controlled Trials
Lactose intolerance (LI) is characterized by the presence of primarily gastrointestinal clinical signs resulting from colonic fermentation of lactose, the absorption of which is impaired due to a deficiency in the lactase enzyme. These clinical signs can be modified by several factors, including lactose dose, residual lactase expression, concurrent ingestion of other dietary components, gut-transit time, and enteric microbiome composition. In many of individuals with lactose malabsorption, clinical signs may be absent after consumption of normal amounts of milk or, in particular, dairy products (yogurt and cheese), which contain lactose partially digested by live bacteria. The intestinal microbiota can be modulated by biotic supplementation, which may alleviate the signs and symptoms of LI. This systematic review summarizes the available evidence on the influence of prebiotics and probiotics on lactase deficiency and LI. The literature search was conducted using the MEDLINE (via PUBMED) and SCOPUS databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and included randomized controlled trials. For each study selected, the risk of bias was assessed following the Cochrane Collaboration methodology. Our findings showed varying degrees of efficacy but an overall positive relationship between probiotics and LI in relation to specific strains and concentrations. Limitations regarding the wide heterogeneity between the studies included in this review should be taken into account. Only one study examined the benefits of prebiotic supplementation and LI. So further clinical trials are needed in order to gather more evidence
Bayesian and maximum likelihood phylogenetic analyses of protein sequence data under relative branch-length differences and model violation
BACKGROUND: Bayesian phylogenetic inference holds promise as an alternative to maximum likelihood, particularly for large molecular-sequence data sets. We have investigated the performance of Bayesian inference with empirical and simulated protein-sequence data under conditions of relative branch-length differences and model violation. RESULTS: With empirical protein-sequence data, Bayesian posterior probabilities provide more-generous estimates of subtree reliability than does the nonparametric bootstrap combined with maximum likelihood inference, reaching 100% posterior probability at bootstrap proportions around 80%. With simulated 7-taxon protein-sequence datasets, Bayesian posterior probabilities are somewhat more generous than bootstrap proportions, but do not saturate. Compared with likelihood, Bayesian phylogenetic inference can be as or more robust to relative branch-length differences for datasets of this size, particularly when among-sites rate variation is modeled using a gamma distribution. When the (known) correct model was used to infer trees, Bayesian inference recovered the (known) correct tree in 100% of instances in which one or two branches were up to 20-fold longer than the others. At ratios more extreme than 20-fold, topological accuracy of reconstruction degraded only slowly when only one branch was of relatively greater length, but more rapidly when there were two such branches. Under an incorrect model of sequence change, inaccurate trees were sometimes observed at less extreme branch-length ratios, and (particularly for trees with single long branches) such trees tended to be more inaccurate. The effect of model violation on accuracy of reconstruction for trees with two long branches was more variable, but gamma-corrected Bayesian inference nonetheless yielded more-accurate trees than did either maximum likelihood or uncorrected Bayesian inference across the range of conditions we examined. Assuming an exponential Bayesian prior on branch lengths did not improve, and under certain extreme conditions significantly diminished, performance. The two topology-comparison metrics we employed, edit distance and Robinson-Foulds symmetric distance, yielded different but highly complementary measures of performance. CONCLUSIONS: Our results demonstrate that Bayesian inference can be relatively robust against biologically reasonable levels of relative branch-length differences and model violation, and thus may provide a promising alternative to maximum likelihood for inference of phylogenetic trees from protein-sequence data
Hubungan Kontrasepsi Hormonal, Pengetahuan dan Sikap Tentang Cuti Haid dengan Praktik Cuti Haid pada Pekerja Perempuan PT. Nyonya Meneer Semarang
Background: According to state role on section 81 undang-undang No 13/2003 mentioned that woman workers who are suffering dismenorrhea during menstruations period could take leave on first and second day menstruation. However not all woman workers in PT.Nyonya Meneer Semarang utilize this policy. One of the reason is using hormonal contraception make their period unstable and irregular. The aim of this study was to analyze about relationships between hormonal contraception usage, knowledge and attitude about menstruation leave and the practice of menstruation leave.Method: This research was an explanatory, with a cross sectional approach. The sample recruited from woman workers of PT. Nyonya Meneer Semarang who have age less than 50 years, not menopause, and using hormonal contraception. 81 woman workers were involved in this study selected by simple random sampling. Chi-square test was employed to test significances between variables.Result: The study shows that there was a relationship between hormonal contraception usages with the practice. However, knowledge and attitude of woman workers have no relation with menstrual leave practice. This study suggest that the company should socialize about determination on menstruation leave and the effect to the woman workers in order to makethe woman workers utilize this rule.Keywords: hormonal contraception, rules of menstruation leave, women worke
Neutron-Capture elements in planetary nebulae: first detections of near-Infrared [Te III] and [Br V] emission lines
We have identified two new near-infrared emission lines in the spectra of
planetary nebulae (PNe) arising from heavy elements produced by neutron capture
reactions: [Te III] 2.1019 m and [Br V] 1.6429 m. [Te III] was
detected in both NGC 7027 and IC 418, while [Br V] was seen in NGC 7027. The
observations were obtained with the medium-resolution spectrograph EMIR on the
10.4m Gran Telescopio Canarias at La Palma, and with the high-resolution
spectrograph IGRINS on the 2.7m Harlan J. Smith telescope at McDonald
Observatory. New calculations of atomic data for these ions, specifically
A-values and collision strengths, are presented and used to derive ionic
abundances of Te and Br. We also derive ionic abundances of other
neutron-capture elements detected in the near-infrared spectra, and estimate
total elemental abundances of Se, Br, Kr, Rb, and Te after correcting for
unobserved ions. Comparison of our derived enrichments to theoretical
predictions from AGB evolutionary models shows reasonable agreement for solar
metallicity progenitor stars of 2 - 4 M. The
spectrally-isolated [Br V] 1.6429 m line has advantages for determining
nebular Br abundances over optical [Br III] emission lines that can be blended
with other features. Finally, measurements of Te are of special interest
because this element lies beyond the first peak of the s-process, and thus
provides new leverage on the abundance pattern of trans-iron species produced
by AGB stars.Comment: 9 pages, 1 figure, 4 tables. Accepted for publication in ApJ Letter
Revealing the Dusty Warm Absorber in MCG--6-30-15 with the Chandra HETG
We present detailed evidence for a warm absorber in the Seyfert 1 galaxy
MCG--6-30-15 and dispute earlier claims for relativistic O line emission. The
HETG spectra show numerous narrow, unresolved (FWHM < 200 km/s) absorption
lines from a wide range of ionization states of N, O, Mg, Ne, Si, S, Ar, and
Fe. The O VII edge and 1s^2--1snp resonance line series to n=9 are clearly
detected at rest in the AGN frame. We attribute previous reports of an
apparently highly redshifted O VII edge to the 1s^2--1snp (n > 5) O VII
resonance lines, and a neutral Fe L absorption complex. The shape of the Fe L
feature is nearly identical to that seen in the spectra of several X-ray
binaries, and in laboratory data. The implied dust column density agrees with
that obtained from reddening studies, and gives the first direct X-ray evidence
for dust embedded in a warm absorber. The O VIII resonance lines and weak edge
are also detected, and the spectral rollover below 2 keV is explained by the
superposition of numerous absorption lines and edges. We identify, for the
first time, a KLL resonance in the O VI photoabsorption cross section, giving a
measure of the O VI column density. The O VII (f) emission detected at the
systemic velocity implies a covering fraction of ~5% (depending on the observed
vs. time-averaged ionizing flux). Our observations show that a dusty warm
absorber model is not only adequate to explain all the spectral features > 0.48
keV (< 26 \AA) the data REQUIRE it. This contradicts the interpretation of
Branduardi-Raymont et al. (2001) that this spectral region is dominated by
highly relativistic line emission from the vicinity of the black hole.Comment: 4.5 pages, 1 color figure, accepted (April 2001) for publication in
ApJL, not many changes from the initial submission - updated/added some
measuements for the O VII resonance series, and added a discussion about FeO2
grain
- âŠ