1,886 research outputs found
Rapid intravenous rehydration of children with acute gastroenteritis and dehydration: a systematic review and meta-analysis
Background: The World Health Organization (WHO) recommends rapid intravenous rehydration, using fluid volumes of 70-100mls/kg over 3–6 h, with some of the initial volume given rapidly as initial fluid boluses to treat hypovolaemic shock for children with acute gastroenteritis (AGE) and severe dehydration. The evidence supporting the safety and efficacy of rapid versus slower rehydration remains uncertain.Methods: We conducted a systematic review of randomised controlled trials (RCTs) on 11th of May 2017 comparing different rates of intravenous fluid therapy in children with AGE and moderate or severe dehydration, using standard search terms. Two authors independently assessed trial quality and extracted data. Non-RCTs and non-English articles were excluded. The primary endpoint was mortality and secondary endpoints included adverse events (safety) and treatment efficacy.Main results: Of the 1390 studies initially identified, 18 were assessed for eligibility. Of these, 3 studies (n = 464) fulfilled a priori criteria for inclusion; most studied children with moderate dehydration and none were conducted in resource-poor settings. Volumes and rates of fluid replacement varied from 20 to 60 ml/kg given over 1-2 h (fast) versus 2-4 h (slow). There was substantial heterogeneity in methodology between the studies with only one adjudicated to be of high quality. There were no deaths in any study. Safety endpoints only identified oedema (n = 6) and dysnatraemia (n = 2). Pooled analysis showed no significant difference between the rapid and slow intravenous rehydration groups for the proportion of treatment failures (N = 468): pooled RR 1.30 (95% CI: 0.87, 1.93) and the readmission rates (N = 439): pooled RR 1.39 (95% CI: 0.68, 2.85).Conclusions: Despite wide implementation of WHO Plan C guideline for severe AGE, we found no clinical evaluation in resource-limited settings, and only limited evaluation of the rate and volume of rehydration in other parts of the world. Recent concerns over aggressive fluid expansion warrants further research to inform guidelines on rates of intravenous rehydration therapy for severe AG
Temperature-Dependent X-Ray Absorption Spectroscopy of Colossal Magnetoresistive Perovskites
The temperature dependence of the O K-edge pre-edge structure in the x-ray
absorption spectra of the perovskites La(1-x)A(x)MnO(3), (A = Ca, Sr; x = 0.3,
0.4) reveals a correlation between the disappearance of the splitting in the
pre-edge region and the presence of Jahn-Teller distortions. The different
magnitudes of the distortions for different compounds is proposed to explain
some dissimilarity in the line shape of the spectra taken above the Curie
temperature.Comment: To appear in Phys. Rev. B, 5 pages, 3 figure
Lord of the Rings: A Kinematic Distance to Circinus X-1 from a Giant X-Ray Light Echo
Circinus X-1 exhibited a bright X-ray flare in late 2013. Follow-up
observations with Chandra and XMM-Newton from 40 to 80 days after the flare
reveal a bright X-ray light echo in the form of four well-defined rings with
radii from 5 to 13 arcminutes, growing in radius with time. The large fluence
of the flare and the large column density of interstellar dust towards Circinus
X-1 make this the largest and brightest set of rings from an X-ray light echo
observed to date. By deconvolving the radial intensity profile of the echo with
the MAXI X-ray lightcurve of the flare we reconstruct the dust distribution
towards Circinus X-1 into four distinct dust concentrations. By comparing the
peak in scattering intensity with the peak intensity in CO maps of molecular
clouds from the Mopra Southern Galactic Plane CO Survey we identify the two
innermost rings with clouds at radial velocity ~ -74 km/s and ~ -81 km/s,
respectively. We identify a prominent band of foreground photoelectric
absorption with a lane of CO gas at ~ -32 km/s. From the association of the
rings with individual CO clouds we determine the kinematic distance to Circinus
X-1 to be kpc. This distance rules out
earlier claims of a distance around 4 kpc, implies that Circinus X-1 is a
frequent super-Eddington source, and places a lower limit of on the Lorentz factor and an upper limit of on the jet viewing angle.Comment: 20 pages, 21 figures, Astrophysical Journal, in prin
Effects of Carbohydrates on Landing Mechanics and Postural Stability During Intermittent High-Intensity Exercise to Fatigue
Please refer to the pdf version of the abstract located adjacent to the title
The Origins of X-ray Line Emissions in Circinus~X-1 at Very Low X-ray Flux
Accretion conditions and morphologies of X-ray transients containing neutron
stars are still poorly understood. Circinus X-1 is an enigmatic case where we
observe X-ray flux changes covering four orders of magnitude. We observed
Circinus X-1 several times at its very lowest X-ray flux using the high energy
transmission grating spectrometer on board the Chandra X-ray Observatory. At a
flux of 1.8 \ergcm we observed a single 1.6 keV blackbody
spectrum. The observed continuum luminosity of 10 \ergsec is about two
orders of magnitude too low to explain the observed photoionized luminosity
suggesting a much more complex structure of the X-ray source which is partially
or entirely obscured as had been previously suggested. This affects most
emissions from the accretion disk including previously observed accretion disk
coronal line emissions. Instead, the strongest observed photoionized lines are
blueshifted by about \kms\ and we suggest that they originate in the
ionized wind of a B5Ia supergaint companion supporting a previous
identification. The neutron star in Cir X-1 is very young and should have a
high magnetic field. At the observed luminosity the emission radius of the
blackbody is small enough to be associated with the accretion hot spot as the
X-ray emitting region. The small emission radius then points to a field
strength below G which would be consistent with the observation of
occasional type I X-ray bursts at high magnetic fields. We discuss Cir X-1 in
the context of being a high-mass X-ray binary with some emphasis on a possible
Be-star X-ray binary nature.Comment: 11 pages, 9 figures, 3 table
Identifying Predictors of Acquired Velopharyngeal Insufficiency in Cleft Lip and Palate Following Maxillary Osteotomy Using Multiple Regression Analyses
Background:
Maxillary osteotomy is typically undertaken to correct abnormal facial growth in cleft lip and palate. The surgery can cause velopharyngeal insufficiency resulting in hypernasality. This study aims to identify valid predictors of acquired velopharyngeal insufficiency following maxillary osteotomy by using a range of perceptual and instrumental speech investigations and multiple regression.
/
Methods:
A prospective study was undertaken consisting of a consecutive series of patients with cleft lip and palate (N = 20) undergoing maxillary osteotomy by a single surgeon. Participants were seen at: 0 to 3 months pre-surgery (T1), 3-months (T2), and 12-months (T3) post-surgery. Hypernasality was rated using the cleft audit protocol for speech-augmented (CAPS-A) and visual analog scales, and nasalance was measured on the Nasometer II 6400. For lateral videofluorosopic and nasendoscopic images, visual perceptual ratings and quantitative ratiometric measurements were undertaken. Multiple regression analyses were undertaken to identify predictors.
/
Results:
T3 models with hypernasality as the dependent variable were found to be a good fit and significant (eg, CAPS-A: R2 = 0.920, F(11,7) = 7.303, P = 0.007). Closure ratio (a quantitative ratiometric measurement) and proportion of palate contacting the posterior pharyngeal wall (a visual perceptual rating) were identified as significant predictors for the CAPS-A model (P = 0.030, P = 0.002)
Parsec-Scale Bipolar X-ray Shocks Produced by Powerful Jets from the Neutron Star Circinus X-1
We report the discovery of multi-scale X-ray jets from the accreting neutron
star X-ray binary, Circinus X-1. The bipolar outflows show wide opening angles
and are spatially coincident with the radio jets seen in new high-resolution
radio images of the region. The morphology of the emission regions suggests
that the jets from Circinus X-1 are running into a terminal shock with the
interstellar medium, as is seen in powerful radio galaxies. This and other
observations indicate that the jets have a wide opening angle, suggesting that
the jets are either not very well collimated or precessing. We interpret the
spectra from the shocks as cooled synchrotron emission and derive a cooling age
of approximately 1600 yr. This allows us to constrain the jet power to be
between 3e35 erg/s and 2e37 erg/s, making this one of a few microquasars with a
direct measurement of its jet power and the only known microquasar that
exhibits stationary large-scale X-ray emission.Comment: 5 pages, 4 figures, to be published in the Astrophysical Journal
Letter
Effect of Maxillary Osteotomy on Speech in Cleft Lip and Palate: Instrumental Outcomes of Velopharyngeal Function
Objective:
To investigate the effect of maxillary osteotomy on velopharyngeal function in cleft lip and palate (CLP) using instrumental measures.
/
Design:
A prospective study.
/
Participants:
A consecutive series of 20 patients with CLP undergoing maxillary osteotomy by a single surgeon were seen at 0 to 3 months presurgery (T1), 3 months (T2), and 12 months (T3) post-surgery.
/
Interventions:
Nasalance was measured on the Nasometer II 6400. For videofluoroscopy and nasendoscopy data, visual perceptual ratings, for example, palatal lift angle (PLAn), and quantitative ratiometric measurements, for example, closure ratio (CRa), were made using a validated methodology and computer software. Reliability studies were undertaken for all instrumental measures.
/
Main Outcome Measures:
Repeated measures analysis of variance (with time at 3 levels) for nasalance and each velar parameter. Planned comparisons across pairs of time points (T1-T2, T1-T3, and T2-T3) including effect sizes.
/
Results:
A significant difference over time was found for nasalance (P = .001) and planned comparisons across pairs of time points were significant between T1 and T2 (P = .008), T1 and T3 (P = .002), but not between T2 and T3 (P = .459) providing evidence that maxillary osteotomy can impact on nasalance adversely and that the changes seen are permanent and stable. There were also significant differences over time for PLAn (P = .012) and CRa (P = −.059) and planned comparisons for both velar parameters reflected similar findings to those of nasalance.
/
Conclusions:
Maxillary osteotomy can adversely affect velopharyngeal function in patients with CLP. The study provides evidence for a much earlier post-surgery review even as early as 3 months after surgery
Food web structure and community composition : a comparison across space and time in the North Sea
Ecological communities are constantly changing as a response to environmental and anthropogenic pressures. Yet, how changes in community composition influence the structure of food webs over time and space remains elusive. Using ecological network analysis, we assessed how food web structure changed across six distinct areas of the North Sea over a sixteen-year time-period. We used multivariate analyses to disentangle and compare spatio-temporal dynamics in community composition (i.e. changes in species abundances) and food web structure (i.e. changes in network properties). Specifically, we assessed how changes in community composition were reflected in food web structure. Our results revealed a strong spatial coupling between community composition and food web structure along a south-north gradient. However, the temporal covariation between community composition and food web structure depended on the spatial scale. We observed a temporal mismatch at regional scale, but a strong coupling at local scale. In particular, we found that community composition can be influenced by hydro-climatic events over large areas, with diverse effects manifesting in local food web structure. Our proposed methodological framework quantified and compared spatio-temporal changes in community composition and food web structure, providing key information to support effective management strategies aimed at conserving the structure and functioning of ecological communities in times of environmental change.Peer reviewe
Anomalous diffusion in polymers: long-time behaviour
We study the Dirichlet boundary value problem for viscoelastic diffusion in
polymers. We show that its weak solutions generate a dissipative semiflow. We
construct the minimal trajectory attractor and the global attractor for this
problem.Comment: 13 page
- …