921 research outputs found
Sensitivity of low energy neutrino experiments to physics beyond the standard model
We study the sensitivity of future low energy neutrino experiments to extra
neutral gauge bosons, leptoquarks and R-parity breaking interactions. We focus
on future proposals to measure coherent neutrino-nuclei scattering and
neutrino-electron elastic scattering. We introduce a new comparative analysis
between these experiments and show that in different types of new physics it is
possible to obtain competitive bounds to those of present and future collider
experiments. For the cases of leptoquarks and R-parity breaking interactions we
found that the expected sensitivity for most of the future low energy
experimental setups is better than the current constraints.Comment: 21 pages, 5 figures. A more detailed analysis of systematic errors is
done. Final version to be published in PR
Effect of statins on atrial fibrillation: collaborative meta-analysis of published and unpublished evidence from randomised controlled trials
Objective To examine whether statins can reduce the risk of atrial fibrillation.
Design Meta-analysis of published and unpublished results from larger scale statin trials, with comparison of the findings against the published results from smaller scale or shorter duration studies.
Data sources Medline, Embase, and Cochrane's CENTRAL up to October 2010. Unpublished data from longer term trials were obtained through contact with investigators.
Study selection Randomised controlled trials comparing statin with no statin or comparing high dose versus standard dose statin; all longer term trials had at least 100 participants and at least six months' follow-up.
Results In published data from 13 short term trials (4414 randomised patients, 659 events), statin treatment seemed to reduce the odds of an episode of atrial fibrillation by 39% (odds ratio 0.61, 95% confidence interval 0.51 to 0.74; P<0.001), but there was significant heterogeneity (P<0.001) between the trials. In contrast, among 22 longer term and mostly larger trials of statin versus control (105 791 randomised patients, 2535 events), statin treatment was not associated with a significant reduction in atrial fibrillation (0.95, 0.88 to 1.03; P=0.24) (P<0.001 for test of difference between the two sets of trials). Seven longer term trials of more intensive versus standard statin regimens (28 964 randomised patients and 1419 events) also showed no evidence of a reduction in the risk of atrial fibrillation (1.00, 0.90 to 1.12; P=0.99).
Conclusions The suggested beneficial effect of statins on atrial fibrillation from published shorter term studies is not supported by a comprehensive review of published and unpublished evidence from larger scale trials
Endo-Porter–Mediated Delivery of Phosphorodiamidate Morpholino Oligos (PMOs) in Erythrocyte Suspension Cultures from Cope\u27s Gray Treefrog Hyla Chrysoscelis
Cope\u27s gray treefrog, Hyla chrysoscelis, is a freeze-tolerant anuran that accumulates cryoprotective glycerol during cold acclimation. H. chrysoscelis erythrocytes express the aquaglyceroporin HC-3, which facilitates transmembrane glycerol and water movement. Aquaglyceroporins have no pharmacological inhibitors, and no genetic knockout tools currently exist for H. chrysoscelis. A phosphorodiamidate morpholino oligo (PMO)–mediated expression knockdown approach was therefore pursued to provide a model for testing the role of HC-3. We describe a novel procedure optimized for specific, efficient knockdown of HC-3 expression in amphibian erythrocyte suspensions cultured at nonmammalian physiological temperatures using Endo-Porter. Our protocol includes three critical components: pre-incubation at 37°C, two rounds of Endo-Porter and HC-3 PMO administration at ~23°C, and continuous shaking at 190 rpm. This combination of steps resulted in 94% reduction in HC-3 protein expression (Western blot), substantial decrease in HC-3 expression in \u3e65% of erythrocytes, and no detectable expression in an additional 30% of cells (immunocytochemistry)
Are environmental characteristics in the municipal eldercare, more closely associated with frequent short sick leave spells among employees than with total sick leave: a cross-sectional study
Background: It has been suggested that frequent-, short-term sick leave is associated with work environment
factors, whereas long-term sick leave is associated mainly with health factors. However, studies of the hypothesis of
an association between a poor working environment and frequent short spells of sick leave are few and results are
inconsistent. Therefore, we aimed to explore associations between self-reported psychosocial work factors and
workplace-registered frequency and length of sick leave in the eldercare sector.
Methods: Employees from the municipal eldercare in Aarhus (N = 2,534) were included. In 2005, they responded to
a work environment questionnaire. Sick leave records from 2005 were dichotomised into total sick leave days (0–14
and above 14 days) and into spell patterns (0–2 short, 3–9 short, and mixed spells and 1–3 long spells). Logistic
regression models were used to analyse associations; adjusted for age, gender, occupation, and number of spells or
sick leave length.
Results: The response rate was 76%; 96% of the respondents were women. Unfavourable mean scores in work
pace, demands for hiding emotions, poor quality of leadership and bullying were best indicated by more than 14
sick leave days compared with 0–14 sick leave days. For work pace, the best indicator was a long-term sick leave
pattern compared with a non-frequent short-term pattern. A frequent short-term sick leave pattern was a better
indicator of emotional demands (1.62; 95% CI: 1.1-2.5) and role conflict (1.50; 95% CI: 1.2-1.9) than a short-term
non-frequent pattern.
Age (= 40 years) statistically significantly modified the association between the 1–3 long-term sick leave
spell pattern and commitment to the workplace compared with the 3–9 frequent short-term pattern.
Conclusions: Total sick leave length and a long-term sick leave spell pattern were just as good or even better
indicators of unfavourable work factor scores than a frequent short-term sick leave pattern. Scores in commitment
to the workplace and quality of leadership varied with sick leave pattern and age. Thus, different sick leave
measures seem to be associated with different work environment factors. Further studies on these associations may
inform interventions to improve occupational health care
Superconducting and Normal State Properties of Neutron Irradiated MgB2
We have performed a systematic study of the evolution of the superconducting
and normal state properties of neutron irradiated MgB wire segments as a
function of fluence and post exposure annealing temperature and time. All
fluences used suppressed the transition temperature, Tc, below 5 K and expanded
the unit cell. For each annealing temperature Tc recovers with annealing time
and the upper critical field, Hc2(T=0), approximately scales with Tc. By
judicious choice of fluence, annealing temperature and time, the Tc of damaged
MgB2 can be tuned to virtually any value between 5 and 39 K. For higher
annealing temperatures and longer annealing times the recovery of Tc tends to
coincide with a decrease in the normal state resistivity and a systematic
recovery of the lattice parameters.Comment: Updated version, to appear in Phys. Rev.
Necessary conditions for accurate computations of three-body partial decay widths
The partial width for decay of a resonance into three fragments is largely
determined at distances where the energy is smaller than the effective
potential producing the corresponding wave function. At short distances the
many-body properties are accounted for by preformation or spectroscopic
factors. We use the adiabatic expansion method combined with the WKB
approximation to obtain the indispensable cluster model wave functions at
intermediate and larger distances. We test the concept by deriving conditions
for the minimal basis expressed in terms of partial waves and radial nodes. We
compare results for different effective interactions and methods. Agreement is
found with experimental values for a sufficiently large basis. We illustrate
the ideas with realistic examples from -emission of C and
two-proton emission of Ne. Basis requirements for accurate momentum
distributions are briefly discussed.Comment: To be published in Physical Review
Identification of mixed-symmetry states in an odd-mass nearly-spherical nucleus
The low-spin structure of 93Nb has been studied using the (n,n' gamma)
reaction at neutron energies ranging from 1.5 to 3.0 MeV and the 94Zr(p,2n
gamma)93Nb reaction at bombarding energies from 11.5 to 19 MeV. States at
1779.7 and 1840.6 keV, respectively, are proposed as mixed-symmetry states
associated with the coupling of a proton hole in the p_1/2 orbit to the 2+_1,ms
state in 94Mo. These assignments are derived from the observed M1 and E2
transition strengths to the symmetric one-phonon states, energy systematics,
spins and parities, and comparison with shell model calculations.Comment: 5 pages, 3 figure
Mathematical Modelling Method Application for Optimisation of Catalytic Reforming process
The application of mathematical modelling method monitoring of catalytic reforming unit of Komsomolsk oil-refinery is proposed. The mathematical model-based system “Catalyst's Control” which takes into account both the physical and chemical mechanisms of hydrocarbon mixture conversion reaction as well as the catalyst deactivation was used for catalytic reforming installation monitoring. The models created can be used for optimization and prediction of operating parameters (octane number, reactors outlet temperature and yield) of the reforming process. It is shown, that the work on the optimal activity allows increasing product output with a constant level of production costs, and get the information about Pt-Re catalyst work efficiency
Very high rotational frequencies and band termination in 73Br
Rotational bands in 73Br have been investigated up to spins of 65/2 using the
EUROBALL III spectrometer. One of the negative-parity bands displays the
highest rotational frequency 1.85 MeV reported to date in nuclei with mass
number greater than 25. At high frequencies, the experimental dynamic moment of
inertia for all bands decrease to very low values, indicating a loss of
collectivity. The bands are described in the configuration-dependent cranked
Nilsson-Strutinsky model. The calculations indicate that one of the
negative-parity bands is observed up to its terminating single-particle state
at spin 63/2. This result establishes the first band termination case in the A
= 70 mass region.Comment: 6 pages, 6 figures, submitted to Phys. Rev. C as a Rapid
Communicatio
Muon capture by 3He nuclei followed by proton and deuteron production
The paper describes an experiment aimed at studying muon capture by
nuclei in pure and mixtures at various densities. Energy distributions of
protons and deuterons produced via and are measured for the
energy intervals MeV and MeV, respectively. Muon capture
rates, and are obtained using two different analysis methods. The
least--squares methods gives , . The Bayes theorem
gives ,
. The experimental
differential capture rates, and , are compared with theoretical
calculations performed using the plane--wave impulse approximation (PWIA) with
the realistic NN interaction Bonn B potential. Extrapolation to the full energy
range yields total proton and deuteron capture rates in good agreement with
former results.Comment: 17 pages, 13 figures, accepted for publication in PR
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