The high-intensity hyperon beam at CERN

A high-intensity hyperon beam was constructed at CERN to deliver Sigma- to experiment WA89 at the Omega facility and operated from 1989 to 1994. The setup allowed rapid changeover between hyperon and conventional hadron beam configurations. The beam provided a Sigma-flux of 1.4 x 10^5 per burst at mean momenta between 330 and 345 Gev/c, produced by about 3 x 10^10 protons of 450 GeV/c . At the experiment target the beam had a Sigma-/pi- ratio close to 0.4 and a size of 1.6 x 3.7 cm^2. The beam particle trajectories and their momenta were measured with a scintillating fibre hodoscope in the beam channel and a silicon microstrip detector at the exit of the channel. A fast transition radiation detector was used to identify the pion component of the beam.Comment: 20 pages, 13 figures. Submitted to Nucl. Instr. Meth.

Der Agitator Ballohd und das Herrnhuterthum in Livland

http://www.ester.ee/record=b3787267*es

Isospin Breaking in Neutron β\beta-decay and SU(3) Violation in Semi-leptonic Hyperon Decays

Present precision measurements of the neutron life time lead to a CKM matrix element $|V_{ud}|$ which is three standard deviations off the value inferred from heavy quark decays etc. We investigate the possibility whether isospin-breaking effects in the neutron-to-proton vector current transition matrix element $=1+\delta g_V$ could eventually close this gap. For that we calculate in chiral perturbation theory the effect of pion and kaon loops on the matrix element $$ taking into account the mass differences of the charged and neutral mesons. We find a negligibly small isospin-breaking effect of $\delta g_V \simeq -4 \cdot 10^{-5}$. The crucial quantity in the analysis of neutron beta-decay precision measurements is thus the radiative correction term $\Delta_R$. Furthermore, we calculate in heavy baryon chiral perturbation theory the SU(3) breaking effects on the vector transition charges of weak semi-leptonic hyperon decays. We find for these quantities channel-dependent relative deviations from the SU(3) limit which range from -10% to $+1$.Comment: 6 pages, 1 figure, to be published in Physical Review C (brief report

SU(3) Breaking in Hyperon Beta Decays: a Prediction for Xi^0 -> Sigma^+ e nu-bar

On the basis of a previous analysis of hyperon semi-leptonic decay data, a prediction is presented for g_1/f_1 in the Xi^0 -> Sigma^+ e nu-bar beta-decay. The analysis takes into account SU(3) breaking in this sector via the inclusion of mass-driven corrections. A rather precise measurement of the above channel by the KTeV experiment at Fermilab will shortly be available. Since the dependence on the SU(3) parameters, F and D, is identical to that of the neutron beta-decay, such a measurement will provide a rather stringent test of SU(3) and the models used to describe its violation in these decays. The prediction given here for the above decay is g_1/f_1=1.17, which leads to a rate of 0.80 x 10^6 s^-1 and thus a branching fraction of 2.3 x 10^-4.Comment: LaTeX, 7 pages, uses acromake, cite and topcapt packages. Non-printing extended ascii characters replaced plus minor correction

Does physical exercise improve ADL capacities in people over 65 years with moderate or severe dementia hospitalized in an acute psychiatric setting? A multisite randomized clinical trial.

Several studies on the effect of physical exercise on activities of daily living (ADL) for people with dementia exist; yet, data concerning the specific context of acute psychiatric hospitals remain scant. This study measured the effect of a physical exercise program on ADL scores in patients with moderate to severe dementia hospitalized in an acute psychiatric ward. A multicenter clinical trial was conducted in five Swiss and Belgian psychiatric hospitals. Participants were randomly allocated to either an experimental group (EG) or a control group (CG). Members of the EG received 20 physical exercise sessions (strengthening, balance, and walking) over a four-week period while members of the CG participated in social interaction sessions of equivalent duration and frequency, but without physical exercise. The effect of exercise on ADL was measured by comparing scores of the Barthel Index and the Functional Independence Measure in the EG and CG before and after the intervention, and two weeks later. Hundred and sixty patients completed the program. Characteristics of participants of both groups were similar at the inception of the study. The mean ADL score of EG decreased slightly over time, whereas that of the CG significantly decreased compared to initial scores. Overall differences between groups were not significant; however, significant differences were found for mobility-related items. ADL scores in elderly with moderate to severe dementia deteriorate during acute psychiatric hospitalization. An exercise program delays the loss of mobility but does not have a significant impact on overall ADL scores

Analytical sensitivity of COVID-19 rapid antigen tests: A case for a robust reference standard

Aggressive diagnostic testing remains an indispensable strategy for health and aged care facilities to prevent the transmission of SARS-CoV-2 in vulnerable populations. The preferred diagnostic platform has shifted towards COVID-19 rapid antigen tests (RATs) to identify the most infectious individuals. As such, RATs are being manufactured faster than at any other time in our history yet lack the relevant quantitative analytics required to inform on absolute analytical sensitivity enabling manufacturers to maintain high batch-to-batch reproducibility, and end-users to accurately compare brands for decision making. Here, we describe a novel reference standard to measure and compare the analytical sensitivity of RATs using a recombinant GFP-tagged nucleocapsid protein (NP-GFP). Importantly, we show that the GFP tag does not interfere with NP detection and provides several advantages affording streamlined protein expression and purification in high yields as well as faster, cheaper and more sensitive quality control measures for post-production assessment of protein solubility and stability. Ten commercial COVID-19 RATs were evaluated and ranked using NP-GFP as a reference standard. Analytical sensitivity data of the selected devices as determined with NP-GFP did not correlate with those reported by the manufacturers using the median tissue culture infectious dose (TCID50) assay. Of note, TCID50 discordance has been previously reported. Taken together, our results highlight an urgent need for a reliable reference standard for evaluation and benchmarking of the analytical sensitivity of RAT devices. NP-GFP is a promising candidate as a reference standard that will ensure that RAT performance is accurately communicated to healthcare providers and the public

Sea Contributions and Nucleon Structure

We suggest a general formalism to treat a baryon as a composite system of three quarks and a `sea'. In this formalism, the sea is a cluster which can consists of gluons and quark-antiquark pairs. The hadron wave function with a sea component is given. The magnetic moments, related sum rules and axial weak coupling constants are obtained. The data seems to favor a vector sea rather than a scalar sea. The quark spin distributions in the nucleon are also discussed.Comment: 24 page

Experiments to Find or Exclude a Long-Lived, Light Gluino

Gluinos in the mass range ~1 1/2 - 3 1/2 GeV are absolutely excluded. Lighter gluinos are allowed, except for certain ranges of lifetime. Only small parts of the mass-lifetime parameter space are excluded for larger masses unless the lifetime is shorter than ~ 2 10^{-11} (m_{gluino}/ GeV) sec. Refined mass and lifetime estimates for R-hadrons are given, present direct and indirect experimental constraints are reviewed, and experiments to find or definitively exclude these possibilities are suggested.Comment: 27 pp, latex with 1 uufiled figure, RU-94-35. New version amplifies discussion of some points and corresponds to version for Phys. Rev.