6,706 research outputs found
Search for fermiophobic Higgs bosons in final states with photons at LEP 2
Higgs boson production with subsequent decay to photons was searched for in
the data collected by the DELPHI detector at centre-of-mass energies between
183 GeV and 209 GeV, corresponding to a total integrated luminosity of nearly
650 pb^{-1}. No evidence for a signal was found, and limits were set on h0Z0
and h0A0 production with h0 decay to photons. These results were used to
exclude regions in the parameter space of fermiophobic scenarios of Two Higgs
Doublet Models.Comment: 24 pages, 6 figures, Accepted by Eur. Phys. J.
Effect on smoking quit rate of telling patients their lung age: the Step2quit randomised controlled trial
Objective To evaluate the impact of telling patients their estimated spirometric lung age as an incentive to quit smoking.Design Randomised controlled trial.Setting Five general practices in Hertfordshire, England.Participants 561 current smokers aged over 35.Intervention All participants were offered spirometric assessment of lung function. Participants in intervention group received their results in terms of "lung age" (the age of the average healthy individual who would perform similar to them on spirometry). Those in the control group received a raw figure for forced expiratory volume at one second (FEV1). Both groups were advised to quit and offered referral to local NHS smoking cessation services.Main outcome measures The primary outcome measure was verified cessation of smoking by salivary cotinine testing 12 months after recruitment. Secondary outcomes were reported changes in daily consumption of cigarettes and identification of new diagnoses of chronic obstructive lung disease.Results Follow-up was 89%. Independently verified quit rates at 12 months in the intervention and control groups, respectively, were 13.6% and 6.4% (difference 7.2%, P=0.005, 95% confidence interval 2.2% to 12.1%; number needed to treat 14). People with worse spirometric lung age were no more likely to have quit than those with normal lung age in either group. Cost per successful quitter was estimated at 280 pound ((euro) 365, $556). A new diagnosis of obstructive lung disease was made in 17% in the intervention group and 14% in the control group; a total of 16% (89/561) of participants.Conclusion Telling smokers their lung age significantly improves the likelihood of them quitting smoking, but the mechanism by which this intervention achieves its effect is unclear.Trial registration National Research Register N0096173751
Impact of a theoretically based sex education programme (SHARE) delivered by teachers on NHS registered conceptions and terminations: final results of cluster randomised trial
<b>Objective</b>: To assess the impact of a theoretically based sex education programme (SHARE) delivered by teachers compared with conventional education in terms of conceptions and terminations registered by the NHS.
Design Follow-up of cluster randomised trial 4.5 years after intervention.
<b>Setting</b>: NHS records of women who had attended 25 secondary schools in east Scotland.
<b>Participants</b>: 4196 women (99.5% of those eligible).
<b>Intervention</b>: SHARE programme (intervention group) v existing sex education (control group).
<b>Main outcome measure</b>: NHS recorded conceptions and terminations for the achieved sample linked at age 20.
<b>Results</b>: In an "intention to treat" analysis there were no significant differences between the groups in registered conceptions per 1000 pupils (300 SHARE v 274 control; difference 26, 95% confidence interval ā33 to 86) and terminations per 1000 pupils (127 v 112; difference 15, ā13 to 42) between ages 16 and 20.
<b>Conclusions</b>: This specially designed sex education programme did not reduce conceptions or terminations by age 20 compared with conventional provision. The lack of effect was not due to quality of delivery. Enhancing teacher led school sex education beyond conventional provision in eastern Scotland is unlikely to reduce terminations in teenagers
Truthful Multi-unit Procurements with Budgets
We study procurement games where each seller supplies multiple units of his
item, with a cost per unit known only to him. The buyer can purchase any number
of units from each seller, values different combinations of the items
differently, and has a budget for his total payment.
For a special class of procurement games, the {\em bounded knapsack} problem,
we show that no universally truthful budget-feasible mechanism can approximate
the optimal value of the buyer within , where is the total number of
units of all items available. We then construct a polynomial-time mechanism
that gives a -approximation for procurement games with {\em concave
additive valuations}, which include bounded knapsack as a special case. Our
mechanism is thus optimal up to a constant factor. Moreover, for the bounded
knapsack problem, given the well-known FPTAS, our results imply there is a
provable gap between the optimization domain and the mechanism design domain.
Finally, for procurement games with {\em sub-additive valuations}, we
construct a universally truthful budget-feasible mechanism that gives an
-approximation in polynomial time with a
demand oracle.Comment: To appear at WINE 201
Identification of decomposition volatile organic compounds from surface deposited and submerged porcine remains
Cadaver dogs are routinely used internationally by police and civilian search organisations to locate human remains on land and in water, yet little is currently known about the volatile organic compounds (VOCs) that are released by a cadaver underwater; how this compares to those given off by a cadaver deposited on land; and ultimately, how this affects the detection of drowned victims by dogs. The aim of this study was to identify the VOCs released by whole porcine (Sus scrofa domesticus) cadavers deposited on the surface and submerged in water using solid phase microextraction gas chromatography mass spectrometry (SPME GCāMS) to ascertain if there are notable differences in decomposition odour depending on the deposition location. For the first time in the UK, the volatile organic compounds (VOCs) from the headspace of decomposing porcine cadavers deposited in both terrestrial and water environments have been detected and identified using SPME-GCMS, including thirteen new VOCs not previously detected from porcine cadavers. Distinct differences were found between the VOCs emitted by porcine cadavers in terrestrial and water environments. In total, seventy-four VOCs were identified from a variety of different chemical classes; carboxylic acids, alcohols, aromatics, aldehydes, ketones, hydrocarbons, esters, ethers, nitrogen compounds and sulphur compounds. Only forty-one VOCs were detected in the headspace of the submerged pigs with seventy detected in the headspace of the surface-deposited pigs. These deposition-dependent differences have important implications for the training of cadaver dogs in the UK. If dog training does not account for these depositional differences, there is potential for human remains to be missed. Whilst the specific odours that elicit a trained response from cadaver dogs remain unknown, this research means that recommendations can be made for the training of cadaver dogs to incorporate different depositions, to account for odour differences and mitigate the possibility of missed human remains operationally
A selected ion flow tube study of the ion-molecule reactions of monochloroethene, trichloroethene and tetrachloroethene
Data for the rate coefficients and product cations of the reactions of a large number of atomic and small molecular cations with monochloroethene, trichloroethene and tetrachloroethene in a selected ion flow tube at 298 K are reported. The recombination energy of the ions range from 6.27 eV (HO) through to 21.56 eV (Ne). Collisional rate coefficients are calculated by modified average dipole orientation theory and compared with experimental values. Thermochemistry and mass balance predict the most feasible neutral products. Together with previously reported results for the three isomers of dichloroethene (J. Phys. Chem. A., 2006, 110, 5760), the fragment ion branching ratios have been compared with those from threshold photoelectron photoion coincidence spectroscopy over the photon energy range 9-22 eV to determine the importance or otherwise of long-range charge transfer. For ions with recombination energy in excess of the ionisation energy of the chloroethene, charge transfer is energetically allowed. The similarity of the branching ratios from the two experiments suggest that long-range charge transfer is dominant. For ions with recombination energy less than the ionisation energy, charge transfer is not allowed; chemical reaction can only occur following formation of an ion-molecule complex, where steric effects are more significant. The products that are now formed and their percentage yield is a complex interplay between the number and position of the chlorine atoms with respect to the C=C bond, where inductive and conjugation effects can be important
High-throughput measurement methodologies for developing nutrient-dense crops
With the development of nutrient-dense crops comes the need for analytical methodologies to enable rapid and accurate analysis of the micronutrients of interest. The analysis of provitamin A carotenoids (pVACs) and the minerals iron (Fe) and zinc (Zn) are the focus of this chapter with the considerations and commonly employed methods discussed. When analyzing samples there are various considerations to minimise analyte degradation (in the case of provitamin A) and reduce possible contamination from external sources (for Fe and Zn). Spectroscopic and chromatographic analyses are the most common analysis approaches utilised when screening for carotenoids. Spectroscopic analyses including near-infrared spectroscopy (NIRS) and iCheck are rapid and require minimal samples preparation and provide fast analysis times. The carotenoids present in the sample is dependent on the crop analyzed and resulting number and concentration of carotenoids present will impact the final decision on suitable analysis techniques. For example, in crops with high concentrations of non-pVACs, chromatographic analysis is necessary in order to accurately quantify the micronutrients. This process is able to accurately identify and quantify individual carotenoids, but requires extensive sample preparation and often long chromatographic separation analysis. When analyzing the minerals Fe and Zn, these same techniques are not suitable, but it is still important to ensure careful sample preparation to deliver accurate analytical results. Degradation of these micronutrients is not a concern, however, possible contamination from soil/ dust/ insects can lead to inaccurate results. Commonly employed analysis such as atomic absorption spectroscopy (AAS) and Inductively Coupled Plasma-Optical Emission Spectrometry ICP-OES or Inductively Coupled Plasma-Mass spectrometry (ICP-MS) require sample digestion prior to analysis and highly pure reagents and gases. These techniques are able to analyze multiple elements and have high accuracy and sensitivity but require specialised facilities and highly trained staff. The use of high-throughput analyses to complement these high-accuracy methods include colorimetric and X-ray flourescence (XRF) technologies. These approaches enable much higher throughput with simple sample preparation and enable screening for micronutrient concentration without the need for specialised facilities.Keywords: Screening, Analysis, Carotenoid, Provitamin A, Iron, Zinc, Micronutrient analysi
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