60 research outputs found
Hadronic contributions to of the leptons and to the effective fine structure constant
The hadronic contributions to the anomalous magnetic moments of the leptons
and to the effective fine structure constant at the Z-mass are reevaluated
using all presently available data.Comment: 36 pages, 11 Postscript figures, available at
ftp://129.129.40.58/pub/preprints/vapogm2.ps.g
Study of the process in the energy region from 0.98 to 1.38 GeV.}
The cross section of the process was measured in
the Spherical Neutral Detector experiment at the VEPP-2M collider in the energy
region MeV. The measured cross section, together
with the and cross sections
obtained in other experiments, was analyzed in the framework of the generalized
vector meson dominance model. It was found that the experimental data can be
described by a sum of , mesons and two and
resonances contributions, with masses
, MeV and
widths , MeV. The analysis of the invariant mass spectra in the energy
region from 1100 to 1380 MeV has shown that for their
descriptionone should take into account the
mechanism also. The phase between the
amplitudes corresponding to the and
intermediate states was measured for the first time. The value of the phase is
close to zero and depends on energy.Comment: 29 pages REVTEX and 17 figures, accepted for publication in Physical
Review
The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape : A Large-Scale Genome-Wide Interaction Study
Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially between men and women. To systematically screen for age-and/or sex-specific effects of genetic variants on BMI and WHRadjBMI, we performed meta-analyses of 114 studies (up to 320,485 individuals of European descent) with genome-wide chip and/or Metabochip data by the Genetic Investigation of Anthropometric Traits (GIANT) Consortium. Each study tested the association of up to similar to 2.8M SNPs with BMI and WHRadjBMI in four strata (men 50y, women 50y) and summary statistics were combined in stratum-specific meta-analyses. We then screened for variants that showed age-specific effects (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed significant (FDR= 50y). No sex-dependent effects were identified for BMI. For WHRadjBMI, we identified 44 loci (27 previously established for main effects, 17 novel) with sex-specific effects, of which 28 showed larger effects in women than in men, five showed larger effects in men than in women, and 11 showed opposite effects between sexes. No age-dependent effects were identified for WHRadjBMI. This is the first genome-wide interaction meta-analysis to report convincing evidence of age-dependent genetic effects on BMI. In addition, we confirm the sex-specificity of genetic effects on WHRadjBMI. These results may providefurther insights into the biology that underlies weight change with age or the sexually dimorphism of body shape.Peer reviewe
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
Sensor networks or smart artifacts?:An exploration of organizational issues of an industrial health and safety monitoring system
Industrial health and safety is an important yet largely unexplored application area of ubiquitous computing. In this paper we investigate the relationship between technology and organization in the context of a concrete industrial health and safety system. The system is designed to reduce the number of incidents of "�vibration white finger"� (VWF) at construction sites and uses wireless sensor nodes for monitoring workers'� exposure to vibrations and testing of compliance with legal health and safety regulations. In particular we investigate the impact of this ubiquitous technology on the relationship between management and operatives, the formulation of health and safety rules and the risk perception and risk behavior of operatives. In addition, we contrast sensor-network inspired and smart artifact inspired compliance systems, and make the case that these technology models have a strong influence on the linkage between technology and organization
Tuning the basicity of synergic bimetallic reagents : switching the regioselectivity of the direct dimetalation of toluene from 2,5-to 3,5-positions
Meta-meta metalation: Remarkably, toluene can be directly dimanganated or dimagnesiated at the 3,5-positions using bimetallic bases with active Me3SiCH2 ligands (see scheme, blue). In contrast, n-butyl ligands lead to 2,5-metalation (red). tmp=2,2,6,6-tetramethylpiperidide
Structural and magnetic insights into the trinuclear ferrocenophane and unexpected hydrido inverse crown products of alkali-metal-mediated manganation(ii) of ferrocene
With the aim of introducing the diisopropylamide [NiPr2]- ligand to alkali-metal-mediated manganation (AMMMn) chemistry, the temperature-dependent reactions of a 1:1:3 mixture of butylsodium, bis(trimethylsilylmethyl)manganese(II), and diisopropylamine with ferrocene in hexane/toluene have been investigated. Performed at reflux temperature, the reaction affords the surprising, ferrocene-free, hydrido product [Na2Mn2 (-H)2{N(iPr)2}4]2 toluene (1), the first Mn hydrido inverse crown complex. Repeating the reaction rationally, excluding ferrocene, produces 1 in an isolated crystalline yield of 62 %. At lower temperatures, the same bimetallic amide mixture leads to the manganation of ferrocene to generate the first trimanganese, trinuclear ferrocenophane, [{Fe(C5H4)2}3{Mn3Na2(NiPr2)2 (HNiPr2)2}] (2) in an isolated crystalline yield of 81 %. Both 1 and 2 have been characterised by X-ray crystallographic studies. The magnetic properties of paramagnetic 1 and 2 have also been examined by variable-temperature magnetisation measurements on powdered samples. For 1, the room-temperature value for T is 3.45 cm3 K mol-1, and on lowering the temperature a strong antiferromagnetic coupling between the two Mn ions is observed. For 2, the room-temperature value for T is 4.06 cm3 K mol-1, which is significantly lower than the expected value for three isolated paramagnetic MnII ions
Bis[(trimethylsilyl)methyl]manganese: structural variations of its solvent-free and tmeda-, pyridine-, and dioxane-complexed forms
First synthesized in 1976 and recently taking on a new significance as a key precursor to heterobimetallic alkali-metal-manganese(II) complexes, bis[(trimethylsilyl)methyl] manganese has been structurally characterized by X-ray crystallography. It forms a polymeric chain structure of formula [{Mn(CH2SiMe3)(2)}(infinity)], 1, in which distorted tetrahedral, spiro Mn atoms are linked together via mu(2)-bonding alkyl ligands. The structure is notable for displaying two distinct categories of Mn-C bond lengths with a mean size differential of 0.225 angstrom and for being the first fully crystallographically characterized polymeric manganese(II) dialkyl compound. Magnetic measurements of 1 indicate a surprisingly strong spin exchange coupling of J approximate to -45 cm(-1) between the manganese ions aligned along the chain. Four Lewis base complexes of bis[(trimethyl silyl)methyl] manganese have also been subjected to X-ray crystallographic studies. Previously known [TMEDA center dot Mn(CH2SiMe3)(2)], 2, and [(pyridine)(2)Mn(CH2SiMe3)(2)], 3, both adopt a simple monomeric arrangement with C2N2 distorted tetrahedral coordinations of the metal atom. Synthesized by direct addition of the Lewis base to 1, two further, new complexes, [{(dioxane)-[Mn(CH2SiMe3)(2)](2)}(infinity)], 4, and [{(dioxane)[Mn(CH2SiMe3)(2)]}(infinity)], 5, are also reported. Hemisolvate 4 displays dimeric [(Me3SiCH2)Mn(mu-CH2SiMe3)(2)Mn(CH2SiMe3)] subunits, whereas 1:1 solvate 5 consists of monomeric subunits of [{Mn(CH2SiMe3)(2)}(infinity)]; in both cases these subunits are linked together via O(CH2CH2)(2)O bridges to generate one-dimensional polymers
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