6,358 research outputs found
Analysis of Serve and Serve-Return Strategies in Elite Male and Female Padel
This aim of this study was to analyze serve and return statistics in elite padel players regarding courtside and gender. The sample contained 668 serves and 600 returns of serves from 14 matches (7 male and 7 female) of the 2019 Masters Finals World Padel Tour. Variables pertaining to serve (number, direction, court side and effectiveness), return of serve (direction, height, stroke type and effectiveness) and point outcome were registered through systematic observation. The main results showed that the serving pair had an advantage in rallies, under 8 shots in women and under 12 shots in men. Statistical differences according to gender and court side were found. Female players execute more backhand and cross-court returns and use more lobs than men. On the right court, serves are more frequently aimed at the "T" and more down the line returns are executed when compared to the left side. Such knowledge could be useful to develop appropriate game strategies and to design specific training exercises based on actual competition context
The Ring Imaging Cherenkov detector (RICH) of the AMS experiment
The Alpha Magnetic Spectrometer (AMS) experiment to be installed on the
International Space Station (ISS) will be equipped with a proximity focusing
Ring Imaging Cherenkov (RICH) detector for measuring the electric charge and
velocity of the charged cosmic particles. A RICH prototype consisting of 96
photomultiplier units, including a piece of the conical reflector, was built
and its performance evaluated with ion beam data. Preliminary results of the
in-beam tests performed with ion fragments resulting from collisions of a 158
GeV/c/nuc primary beam of Indium ions (CERN SPS) on a Pb target are reported.
The collected data included tests to the final front-end electronics and to
different aerogel radiators. Cherenkov rings for a large range of charged
nuclei and with reflected photons were observed. The data analysis confirms the
design goals. Charge separation up to Fe and velocity resolution of the order
of 0.1% for singly charged particles are obtained.Comment: 29th International Conference on Cosmic Rays (Pune, India
Variabilin: A dual inhibitor of human secretory and cytosolic phospholipase A2 with antiinflammatory activity
ABSTRACT The marine product variabilin was identified as a novel inhibitor of phospholipase A 2 (PLA 2 ), which exhibited IC 50 values of 6.9 M and 7.9 M for human synovial secretory PLA 2 and U937 cells cytosolic PLA 2 activities, respectively. This compound was less potent on bee venom or zymosan-injected rat air pouch enzymes and failed to affect Naja naja venom PLA 2 . The production of leukotriene B 4 by human neutrophils stimulated with calcium ionophore A23187 was also inhibited by variabilin, which was without effect on 5-lipoxygenase, cyclo-oxygenase 1 and cyclo-oxygenase 2 activities in cell-free assays. Other functions of human neutrophils, such as degranulation and superoxide generation, were also significantly reduced in vitro. Variabilin administered topically suppressed the mouse ear edema induced by 12-O-tetradecanoylphorbol 13-acetate, whereas the ear edema induced by arachidonic acid was unaffected; this suggests an action previous to arachidonic acid metabolism. This compound administered p.o. at 30 mg/kg and 45 mg/kg significantly inhibited mouse paw edema induced by carrageenan and, at 0.01 to 1.0 mol/pouch in the mouse air pouch injected with zymosan, exerted a marked inhibition on PGE 2 and leukotriene B 4 levels in exudates (ID 50 values of approximately 0.028 -0.029 mol/pouch), without affecting cell migration. Our results indicate that variabilin is an inhibitor of human secretory and cytosolic PLA 2 activities that controls eicosanoid production in vitro and in vivo, inhibits neutrophil degranulation and superoxide generation in vitro and shows anti-inflammatory activity after topical or p.o. administration to mice
Search for Charged Current Coherent Pion Production on Carbon in a Few-GeV Neutrino Beam
The SciBooNE Collaboration has performed a search for charged current
coherent pion production from muon neutrinos scattering on carbon, \nu_\mu
^{12}C \to \mu^- ^{12}C \pi^+, with two distinct data samples. No evidence for
coherent pion production is observed. We set 90% confidence level upper limits
on the cross section ratio of charged current coherent pion production to the
total charged current cross section at 0.67\times 10^{-2} at mean neutrino
energy 1.1 GeV and 1.36\times 10^{-2} at mean neutrino energy 2.2 GeV.Comment: 18 pages, 16 figures, Minor revisions to match version accepted for
publication in Physical Review
Measurement of inclusive charged current interactions on carbon in a few-GeV neutrino beam
The SciBooNE Collaboration reports a measurement of inclusive charged current
interactions of muon neutrinos on carbon with an average energy of 0.8 GeV
using the Fermilab Booster Neutrino Beam. We compare our measurement with two
neutrino interaction simulations: NEUT and NUANCE. The charged current
interaction rates (product of flux and cross section) are extracted by fitting
the muon kinematics, with a precision of 6-15% for the energy dependent and 3%
for the energy integrated analyses. We also extract CC inclusive interaction
cross sections from the observed rates, with a precision of 10-30% for the
energy dependent and 8% for the energy integrated analyses. This is the first
measurement of the CC inclusive cross section on carbon around 1 GeV. These
results can be used to convert previous SciBooNE cross section ratio
measurements to absolute cross section values.Comment: 21 pages, 16 figures. Accepted by Phys. Rev. D. Minor revisions to
match the accepted versio
Electron quantum metamaterials in van der Waals heterostructures
In recent decades, scientists have developed the means to engineer synthetic
periodic arrays with feature sizes below the wavelength of light. When such
features are appropriately structured, electromagnetic radiation can be
manipulated in unusual ways, resulting in optical metamaterials whose function
is directly controlled through nanoscale structure. Nature, too, has adopted
such techniques -- for example in the unique coloring of butterfly wings -- to
manipulate photons as they propagate through nanoscale periodic assemblies. In
this Perspective, we highlight the intriguing potential of designer
sub-electron wavelength (as well as wavelength-scale) structuring of electronic
matter, which affords a new range of synthetic quantum metamaterials with
unconventional responses. Driven by experimental developments in stacking
atomically layered heterostructures -- e.g., mechanical pick-up/transfer
assembly -- atomic scale registrations and structures can be readily tuned over
distances smaller than characteristic electronic length-scales (such as
electron wavelength, screening length, and electron mean free path). Yet
electronic metamaterials promise far richer categories of behavior than those
found in conventional optical metamaterial technologies. This is because unlike
photons that scarcely interact with each other, electrons in subwavelength
structured metamaterials are charged, and strongly interact. As a result, an
enormous variety of emergent phenomena can be expected, and radically new
classes of interacting quantum metamaterials designed
Experimental study of the atmospheric neutrino backgrounds for proton decay to positron and neutral pion searches in water Cherenkov detectors
The atmospheric neutrino background for proton decay to positron and neutral
pion in ring imaging water Cherenkov detectors is studied with an artificial
accelerator neutrino beam for the first time. In total, about 314,000 neutrino
events corresponding to about 10 megaton-years of atmospheric neutrino
interactions were collected by a 1,000 ton water Cherenkov detector (KT). The
KT charged-current single neutral pion production data are well reproduced by
simulation programs of neutrino and secondary hadronic interactions used in the
Super-Kamiokande (SK) proton decay search. The obtained proton to positron and
neutral pion background rate by the KT data for SK from the atmospheric
neutrinos whose energies are below 3 GeV is about two per megaton-year. This
result is also relevant to possible future, megaton-scale water Cherenkov
detectors.Comment: 13 pages, 16 figure
Search for Branons at LEP
We search, in the context of extra-dimension scenarios, for the possible
existence of brane fluctuations, called branons. Events with a single photon or
a single Z-boson and missing energy and momentum collected with the L3 detector
in e^+ e^- collisions at centre-of-mass energies sqrt{s}=189-209$ GeV are
analysed. No excess over the Standard Model expectations is found and a lower
limit at 95% confidence level of 103 GeV is derived for the mass of branons,
for a scenario with small brane tensions. Alternatively, under the assumption
of a light branon, brane tensions below 180 GeV are excluded
K0s K0s Final State in Two-Photon Collisions and Implications for Glueballs
The K0s K0s final state in two-photon collisions is studied with the L3
detector at LEP. The mass spectrum is dominated by the formation of the
f_2'(1525) tensor meson in the helicity-two state with a two-photon width times
the branching ratio into K Kbar of 76 +- 6 +- 11 eV. A clear signal for the
formation of the f_J(1710) is observed and it is found to be dominated by the
spin-two helicity-two state. No resonance is observed in the mass region around
2.2 GeV and an upper limit of 1.4 eV at 95% C.L. is derived for the two-photon
width times the branching ratio into K0s K0s for the glueball candidate
xi(2230)
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