199 research outputs found
We\u27re With You, Boys, We\u27re With You!
https://digitalcommons.library.umaine.edu/mmb-vp/3403/thumbnail.jp
Changes in physical health among participants in a multidisciplinary health programme for long-term unemployed persons
Background. The relationship between poor health and unemployment is well established. Health promotion among unemployed persons may improve their health. The aims of this study were to investigate characteristics of non-participants and drop-outs in a multidisciplinary health promotion programme for long-term unemployed persons with health complaints, to evaluate changes in physical health among participants, and to investigate determinants of improvement in physical health. Methods. A longitudinal, non-controlled design was used. The programme consisted of two weekly exercise sessions and one weekly cognitive session during 12 weeks. The main outcome measures were body mass index, blood pressure, cardiorespiratory fitness, abd
Evidence for the h_b(1P) meson in the decay Upsilon(3S) --> pi0 h_b(1P)
Using a sample of 122 million Upsilon(3S) events recorded with the BaBar
detector at the PEP-II asymmetric-energy e+e- collider at SLAC, we search for
the spin-singlet partner of the P-wave chi_{bJ}(1P) states in the
sequential decay Upsilon(3S) --> pi0 h_b(1P), h_b(1P) --> gamma eta_b(1S). We
observe an excess of events above background in the distribution of the recoil
mass against the pi0 at mass 9902 +/- 4(stat.) +/- 2(syst.) MeV/c^2. The width
of the observed signal is consistent with experimental resolution, and its
significance is 3.1sigma, including systematic uncertainties. We obtain the
value (4.3 +/- 1.1(stat.) +/- 0.9(syst.)) x 10^{-4} for the product branching
fraction BF(Upsilon(3S)-->pi0 h_b) x BF(h_b-->gamma eta_b).Comment: 8 pages, 4 postscript figures, submitted to Phys. Rev. D (Rapid
Communications
Transverse Emittance Reduction in Muon Beams by Ionization Cooling
Accelerated muon beams have been considered for next-generation studies of
high-energy lepton-antilepton collisions and neutrino oscillations. However,
high-brightness muon beams have not yet been produced. The main challenge for
muon acceleration and storage stems from the large phase-space volume occupied
by the beam, derived from the muon production mechanism through the decay of
pions from proton collisions. Ionization cooling is the technique proposed to
decrease the muon beam phase-space volume. Here we demonstrate a clear signal
of ionization cooling through the observation of transverse emittance reduction
in beams that traverse lithium hydride or liquid hydrogen absorbers in the Muon
Ionization Cooling Experiment (MICE). The measurement is well reproduced by the
simulation of the experiment and the theoretical model. The results shown here
represent a substantial advance towards the realization of muon-based
facilities that could operate at the energy and intensity frontiers.Comment: 23 pages and 5 figure
First demonstration of ionization cooling by the Muon Ionization Cooling Experiment
High-brightness muon beams of energy comparable to those produced by
state-of-the-art electron, proton and ion accelerators have yet to be realised.
Such beams have the potential to carry the search for new phenomena in
lepton-antilepton collisions to extremely high energy and also to provide
uniquely well-characterised neutrino beams. A muon beam may be created through
the decay of pions produced in the interaction of a proton beam with a target.
To produce a high-brightness beam from such a source requires that the phase
space volume occupied by the muons be reduced (cooled). Ionization cooling is
the novel technique by which it is proposed to cool the beam. The Muon
Ionization Cooling Experiment collaboration has constructed a section of an
ionization cooling cell and used it to provide the first demonstration of
ionization cooling. We present these ground-breaking measurements.Comment: 19 pages and 6 figure
Demonstration of cooling by the Muon Ionization Cooling Experiment
The use of accelerated beams of electrons, protons or ions has furthered the development of nearly every scientific discipline. However, high-energy muon beams of equivalent quality have not yet been delivered. Muon beams can be created through the decay of pions produced by the interaction of a proton beam with a target. Such âtertiaryâ beams have much lower brightness than those created by accelerating electrons, protons or ions. High-brightness muon beams comparable to those produced by state-of-the-art electron, proton and ion accelerators could facilitate the study of leptonâantilepton collisions at extremely high energies and provide well characterized neutrino beams1,2,3,4,5,6. Such muon beams could be realized using ionization cooling, which has been proposed to increase muon-beam brightness7,8. Here we report the realization of ionization cooling, which was confirmed by the observation of an increased number of low-amplitude muons after passage of the muon beam through an absorber, as well as an increase in the corresponding phase-space density. The simulated performance of the ionization cooling system is consistent with the measured data, validating designs of the ionization cooling channel in which the cooling process is repeated to produce a substantial cooling effect9,10,11. The results presented here are an important step towards achieving the muon-beam quality required to search for phenomena at energy scales beyond the reach of the Large Hadron Collider at a facility of equivalent or reduced footprint6
First demonstration of ionization cooling by the muon ionization cooling experiment
High-brightness muon beams of energy comparable to those produced by state-of-the-art electron, proton and ion accelerators have yet to be realised. Such beams have the potential to carry the search for new phenomena in lepton-antilepton collisions to extremely high energy and also to provide uniquely well-characterised neutrino beams. A muon beam may be created through the decay of pions produced in the interaction of a proton beam with a target. To produce a high-brightness beam from such a source requires that the phase space volume occupied by the muons be reduced (cooled). Ionization cooling is the novel technique by which it is proposed to cool the beam. The Muon Ionization Cooling Experiment collaboration has constructed a section of an ionization cooling cell and used it to provide the first demonstration of ionization cooling. We present these ground-breaking measurements
Local actin polymerization during endocytic carrier formation
Extracellular macromolecules, pathogens and cell surface proteins rely on endocytosis to enter cells. Key steps of endocytic carrier formation are cargo molecule selection, plasma membrane folding and detachment from the cell surface. While dedicated proteins mediate each step, the actin cytoskeleton contributes to all. However, its role can be indirect to the actual molecular events driving endocytosis. Here, we review our understanding of the molecular steps mediating local actin polymerization during the formation of endocytic carriers. Clathrin-mediated endocytosis (CME) is the least reliant on local actin polymerization, as it is only engaged to counter forces induced by membrane tension or cytoplasmic pressure. Two opposite situations are coated pit formation in yeast and at the basolateral surface of polarized mammalian cells which are respectively dependent and independent on actin polymerization. Conversely, Clathrin-independent endocytosis (CIE) forming both nanometer (CLIC/GEEC, caveolae, FEME, IL2ÎČ uptake) and micrometer carriers (macropinocytosis) are dependent on actin polymerization to power local membrane deformation and carrier budding. A variety of endocytic adaptors can recruit and activate the Cdc42/N-WASP or Rac1/WAVE complexes, which in turn engage the Arp2/3 complex, thereby mediating local actin polymerization at the membrane. However, the molecular steps for RhoA and formin-mediated actin bundling during endocytic pit formation remains unclear
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