311 research outputs found
Measurement of tau polarization in e+ e- annihilation at sqrt{s}=58 GeV
The polarization of tau leptons in the reaction e+ e- --> tau+ tau- has been
measured using a e+e- collider, TRISTAN, at the center-of-mass energy of 58
GeV. From the kinematical distributions of daughter particles in tau --> e nu
nu-bar, mu nu nu-bar, rho nu or pi(K) nu decays, the average polarization of
tau- and its forward-backward asymmetry have been evaluated to be 0.012 +-
0.058 and 0.029 +- 0.057, respectively.Comment: 18 pages, 5 figure
Study of variable stars in the MOA data base: long-period red variables in the Large Magellanic Cloud
One hundred and forty six long-period red variable stars in the Large
Magellanic Cloud (LMC) from the three year MOA project database were analysed.
A careful periodic analysis was performed on these stars and a catalogue of
their magnitudes, colours, periods and amplitudes is presented. We convert our
blue and red magnitudes to band values using 19 oxygen-rich stars. A group
of red short-period stars separated from the Mira sequence has been found on a
(log P, K) diagram. They are located at the short period side of the Mira
sequence consistent with the work of Wood and Sebo (1996). There are two
interpretations for such stars; a difference in pulsation mode or a difference
in chemical composition. We investigated the properties of these stars together
with their colour, amplitude and periodicity. We conclude that they have small
amplitudes and less regular variability. They are likely to be higher mode
pulsators. A large scatter has been also found on the long period side of the
(log P, K) diagram. This is possibly a systematic spread given that the blue
band of our photometric system covers both standard B and V bands and affects
carbon-rich stars.Comment: 19 pages, 19 figures, accepted for publication in MNRA
Measurement and comparison of individual external doses of high-school students living in Japan, France, Poland and Belarus -- the "D-shuttle" project --
Twelve high schools in Japan (of which six are in Fukushima Prefecture), four
in France, eight in Poland and two in Belarus cooperated in the measurement and
comparison of individual external doses in 2014. In total 216 high-school
students and teachers participated in the study. Each participant wore an
electronic personal dosimeter "D-shuttle" for two weeks, and kept a journal of
his/her whereabouts and activities. The distributions of annual external doses
estimated for each region overlap with each other, demonstrating that the
personal external individual doses in locations where residence is currently
allowed in Fukushima Prefecture and in Belarus are well within the range of
estimated annual doses due to the background radiation level of other
regions/countries
On Planetary Companions to the MACHO-98-BLG-35 Microlens Star
We present observations of microlensing event MACHO-98-BLG-35 which reached a
peak magnification factor of almost 80. These observations by the Microlensing
Planet Search (MPS) and the MOA Collaborations place strong constraints on the
possible planetary system of the lens star and show intriguing evidence for a
low mass planet with a mass fraction . A giant planet with is excluded from 95%
of the region between 0.4 and 2.5 from the lens star, where is the
Einstein ring radius of the lens. This exclusion region is more extensive than
the generic "lensing zone" which is . For smaller mass planets,
we can exclude 57% of the "lensing zone" for and 14% of
the lensing zone for . The mass fraction corresponds to an Earth mass planet for a lensing star of mass \sim
0.3 \msun. A number of similar events will provide statistically significant
constraints on the prevalence of Earth mass planets. In order to put our limits
in more familiar terms, we have compared our results to those expected for a
Solar System clone averaging over possible lens system distances and
orientations. We find that such a system is ruled out at the 90% confidence
level. A copy of the Solar System with Jupiter replaced by a second Saturn mass
planet can be ruled out at 70% confidence. Our low mass planetary signal (few
Earth masses to Neptune mass) is significant at the confidence
level. If this planetary interpretation is correct, the MACHO-98-BLG-35 lens
system constitutes the first detection of a low mass planet orbiting an
ordinary star without gas giant planets.Comment: ApJ, April 1, 2000; 27 pages including 8 color postscript figure
Belle II Technical Design Report
The Belle detector at the KEKB electron-positron collider has collected
almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an
upgrade of KEKB is under construction, to increase the luminosity by two orders
of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2
/s luminosity. To exploit the increased luminosity, an upgrade of the Belle
detector has been proposed. A new international collaboration Belle-II, is
being formed. The Technical Design Report presents physics motivation, basic
methods of the accelerator upgrade, as well as key improvements of the
detector.Comment: Edited by: Z. Dole\v{z}al and S. Un
New insight into kinetics behavor of the structural formation process in Agar gelation
A time-resolved experimental study on the kinetics and relaxation of the
structural formation process in gelling Agar-water solutions was carried out
using our custom-built torsion resonator. The study was based on measurements
of three naturally cooled solutions with agar concentrations of 0.75%, 1.0% and
2.0% w/w. It was found that the natural-cooling agar gelation process could be
divided into three stages, sol stage (Stage I), gelation zone (Stage II) and
gel stage (Stage III), based on the time/temperature evolutions of the
structural development rate (SDR). An interesting fluctuant decaying behavior
of SDR was observed in Stage II and III, indicative of a sum of multiple
relaxation processes and well described by a multiple-order Gaussisn-like
equation: . More interestingly, the temperature dependences of the fitted
values of Wn in Stage II and Stage III were found to follow the different
Arrhenius laws, with different activation energies of EaII= 39-74 KJ/mol and
EaIII~7.0 KJ/mol. The two different Arrhenius-like behaviors respectively
suggest that dispersions in Stage II be attributed to the relaxation of the
self-assembly of agar molecules or the growth of junction zones en route to
gelation, in which the formation or fission of hydrogen bonding interactions
plays an important role; and that dispersions in Stage III be attributed to the
relaxation dynamics of water released from various size domains close to the
domain of the viscous flow of water during the syneresis process.Comment: 24 pages, 4 figures, 1 tabl
No Benefit from Chronic Lithium Dosing in a Sibling-Matched, Gender Balanced, Investigator-Blinded Trial Using a Standard Mouse Model of Familial ALS
Background: In any animal model of human disease a positive control therapy that demonstrates efficacy in both the animal model and the human disease can validate the application of that animal model to the discovery of new therapeutics. Such a therapy has recently been reported by Fornai et al. using chronic lithium carbonate treatment and showing therapeutic efficacy in both the high-copy SOD1G93A mouse model of familial amyotrophic lateral sclerosis (ALS), and in human ALS patients. Methodology/Principal Findings: Seeking to verify this positive control therapy, we tested chronic lithium dosing in a sibling-matched, gender balanced, investigator-blinded trial using the high-copy (average 23 copies) SOD1G93A mouse (n = 27â28/group). Lithium-treated mice received single daily 36.9 mg/kg i.p. injections from 50 days of age through death. This dose delivered 1 mEq/kg (6.94 mg/kg/day lithium ions). Neurological disease severity score and body weight were determined daily during the dosing period. Age at onset of definitive disease and survival duration were recorded. Summary measures from individual body weight changes and neurological score progression, age at disease onset, and age at death were compared using Kaplan-Meier and Cox proportional hazards analysis. Our study did not show lithium efficacy by any measure. Conclusions/Significance: Rigorous survival study design that includes sibling matching, gender balancing, investigato
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