3,757 research outputs found
Nutritional support for head-injured patients
Copyright John Wiley & Sons. This review is published as a Cochrane Review in the Cochrane Database of Systematic Reviews 2004, Issue 3. Cochrane Reviews are regularly updated as new evidence emerges and in response to comments and criticisms, and the Cochrane Database of Systematic Reviews should be consulted for the most recent version of the Review.β Perel, P. , Yanagawa, T. , Bunn, F. , Roberts, I. , Wentz, R. and Pierro, A. Nutritional support for head-injured patients. Cochrane Database of Systematic Reviews 2004, Issue 3. Art. No.: CD001530. DOI: 10.1002/14651858.CD001530.pub2Background: Head injury increases the body's metabolic responses, and therefore nutritional demands. Provision of an adequate supply of nutrients is associated with improved outcome. The best route for administering nutrition (parenterally (TPN) or enterally (EN)), and the best timing of administration (for example, early versus late) of nutrients needs to be established. Objectives: To quantify the effect on mortality and morbidity of alternative strategies of providing nutritional support following head injury. Search strategy: Trials were identified by computerised searches of the Cochrane Injuries Group specialised register, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, National Research Register, Web of Science and other electronic trials registers. Reference lists of trials and review articles were checked. The searches were last updated in July 2006. Selection criteria: Randomised controlled trials of timing or route of nutritional support following acute traumatic brain injury. Data collection and analysis: Two authors independently abstracted data and assessed trial quality. Information was collected on death, disability, and incidence of infection. If trial quality was unclear, or if there were missing outcome data, trialists were contacted in an attempt to get further information. Main results: A total of 11 trials were included. Seven trials addressed the timing of support (early versus delayed), data on mortality were obtained for all seven trials (284 participants). The relative risk (RR) for death with early nutritional support was 0.67 (95% CI 0.41 to 1.07). Data on disability were available for three trials. The RR for death or disability at the end of follow-up was 0.75 (95% CI 0.50 to 1.11). Seven trials compared parenteral versus enteral nutrition. Because early support often involves parenteral nutrition, three of the trials are also included in the previous analyses. Five trials (207 participants) reported mortality. The RR for mortality at the end of follow-up period was 0.66 (0.41 to 1.07). Two trials provided data on death and disability. The RR was 0.69 (95% Cl 0.40 to 1.19). One trial compared gastric versus jejunal enteral nutrition, there were no deaths and the RR was not estimable. Authors' conclusions: This review suggests that early feeding may be associated with a trend towards better outcomes in terms of survival and disability. Further trials are required. These trials should report not only nutritional outcomes but also the effect on death and disability.Peer reviewe
Systematic Errors in Cosmic Microwave Background Interferometry
Cosmic microwave background (CMB) polarization observations will require
superb control of systematic errors in order to achieve their full scientific
potential, particularly in the case of attempts to detect the B modes that may
provide a window on inflation. Interferometry may be a promising way to achieve
these goals. This paper presents a formalism for characterizing the effects of
a variety of systematic errors on interferometric CMB polarization
observations, with particular emphasis on estimates of the B-mode power
spectrum. The most severe errors are those that couple the temperature
anisotropy signal to polarization; such errors include cross-talk within
detectors, misalignment of polarizers, and cross-polarization. In a B mode
experiment, the next most serious category of errors are those that mix E and B
modes, such as gain fluctuations, pointing errors, and beam shape errors. The
paper also indicates which sources of error may cause circular polarization
(e.g., from foregrounds) to contaminate the cosmologically interesting linear
polarization channels, and conversely whether monitoring of the circular
polarization channels may yield useful information about the errors themselves.
For all the sources of error considered, estimates of the level of control that
will be required for both E and B mode experiments are provided. Both
experiments that interfere linear polarizations and those that interfere
circular polarizations are considered. The fact that circular experiments
simultaneously measure both linear polarization Stokes parameters in each
baseline mitigates some sources of error.Comment: 19 pages, 9 figures, submitted to Phys. Rev.
Metamaterials: optical activity without chirality
We report that the classical phenomenon of optical activity, which is traditionally associated with chirality (helicity) of organic molecules, proteins, and inorganic structures, can be observed in artificial planar media which exhibit neither 3D nor 2D chirality. We observe the effect in the microwave and optical parts of the spectrum at oblique incidence to regular arrays of nonchiral subwavelength metamolecules in the form of strong circular dichroism and birefringence indistinguishable from those of chiral three-dimensional media
Cosmological Consequences of String-forming Open Inflation Models
We present a study of open inflation cosmological scenarios in which cosmic
strings form betwen the two inflationary epochs. It is shown that in these
models strings are stretched outside the horizon due to the inflationary
expansion but must necessarily re-enter the horizon before the epoch of equal
matter and radiation densities. We determine the power spectrum of cold dark
matter perturbations in these hybrid models, finding good agreement with
observations for values of and comparable
contributions from the active and passive sources to the CMB. Finally, we
briefly discuss other cosmological consequences of these models.Comment: 11 LaTeX pages with 3 eps figure
A gender-sensitised weight loss and healthy living programme for overweight and obese men delivered by Scottish Premier League football clubs (FFIT): a pragmatic randomised controlled trial.
BACKGROUND: The prevalence of male obesity is increasing but few men take part in weight loss programmes. We assessed the effect of a weight loss and healthy living programme on weight loss in football (soccer) fans. METHODS: We did a two-group, pragmatic, randomised controlled trial of 747 male football fans aged 35-65 years with a body-mass index (BMI) of 28 kg/m(2) or higher from 13 Scottish professional football clubs. Participants were randomly assigned with SAS (version 9Β·2, block size 2-9) in a 1:1 ratio, stratified by club, to a weight loss programme delivered by community coaching staff in 12 sessions held every week. The intervention group started a weight loss programme within 3 weeks, and the comparison group were put on a 12 month waiting list. All participants received a weight management booklet. Primary outcome was mean difference in weight loss between groups at 12 months, expressed as absolute weight and a percentage of their baseline weight. Primary outcome assessment was masked. Analyses were based on intention to treat. The trial is registered with Current Controlled Trials, number ISRCTN32677491. FINDINGS: 374 men were allocated to the intervention group and 374 to the comparison group. 333 (89%) of the intervention group and 355 (95%) of the comparison group completed 12 month assessments. At 12 months the mean difference in weight loss between groups, adjusted for baseline weight and club, was 4Β·94 kg (95% CI 3Β·95-5Β·94) and percentage weight loss, similarly adjusted, was 4Β·36% (3Β·64-5Β·08), both in favour of the intervention (p<0Β·0001). Eight serious adverse events were reported, five in the intervention group (lost consciousness due to drugs for pre-existing angina, gallbladder removal, hospital admission with suspected heart attack, ruptured gut, and ruptured Achilles tendon) and three in the comparison group (transient ischaemic attack, and two deaths). Of these, two adverse events were reported as related to participation in the programme (gallbladder removal and ruptured Achilles tendon). INTERPRETATION: The FFIT programme can help a large proportion of men to lose a clinically important amount of weight; it offers one effective strategy to challenge male obesity. FUNDING: Scottish Government and The UK Football Pools funded delivery of the programme through a grant to the Scottish Premier League Trust. The National Institute for Health Research Public Health Research Programme funded the assessment (09/3010/06)
Inverting the Sachs-Wolfe Formula: an Inverse Problem Arising in Early-Universe Cosmology
The (ordinary) Sachs-Wolfe effect relates primordial matter perturbations to
the temperature variations in the cosmic microwave background
radiation; can be observed in all directions around us. A standard
but idealised model of this effect leads to an infinite set of moment-like
equations: the integral of with respect to k ()
is equal to a given constant, , for . Here, P is the
power spectrum of the primordial density variations, is a spherical
Bessel function and y is a positive constant. It is shown how to solve these
equations exactly for ~. The same solution can be recovered, in
principle, if the first ~m equations are discarded. Comparisons with classical
moment problems (where is replaced by ) are made.Comment: In Press Inverse Problems 1999, 15 pages, 0 figures, Late
Observation and studies of jet quenching in PbPb collisions at βsNN = 2.76 TeV
Jet production in PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV was studied with the Compact Muon Solenoid (CMS) detector at the LHC, using a data sample corresponding to an integrated luminosity of 6.7 ΞΌb^(β1). Jets are reconstructed using the energy deposited in the CMS calorimeters and studied as a function of collision centrality. With increasing collision centrality, a striking imbalance in dijet transverse
momentum is observed, consistent with jet quenching. The observed effect extends from the lower cutoff used
in this study (jet pT = 120 GeV/c) up to the statistical limit of the available data sample (jet pT β 210 GeV/c).
Correlations of charged particle tracks with jets indicate that the momentum imbalance is accompanied by a softening of the fragmentation pattern of the second most energetic, away-side jet. The dijet momentum balance is recovered when integrating low transverse momentum particles distributed over a wide angular range relative to the direction of the away-side jet
Long-term sustainability of bio-components production
Biofuels play an increasingly important role in motor fuel market. The list of biofuels (bio-components) in accordance with EU legislations contains a number of substances not widely used in the market. Traditionally these include: fatty acid methyl esters (FAME, in the Czech Republic methyl ether of rape seed oil) and bioethanol (also ethyl terc. buthyl ether ETBE, based on bioethanol). The availability and possible utilizations of bio-component fuels in Czech Republic and Serbia are discussed. Additional attention is paid on the identification of the possibilities to improve effectiveness of rape seeds cultivation and utilization of by-products from FAME production (utilization of sew, rape-meal and glycerol) which will allow fulfilment of the sustainability criteria for the first generation biofuels. The new approaches on renewable co-processing are commented. The concept of 3E (emissions, energy demand, and economics) is introduced specifying three main attributes for effective production of FAME production in accordance with legal compliances. Bio-components price change is analyzed in comparison to the price of motor fuels, identifying possible (speculative) crude price break-even point at the level of 149-176 USD/bbl at which point bio-fuels would become economically cost effective for the use by refiners
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