350 research outputs found
Nuclear abnormalities in aspirated thyroid cells and chromosome aberrations in lymphocytes of residents near the Semipalatinsk Nuclear Test Site
Chromosomal studies in peripheral lymphocytes from 63 residents near the Semipalatinsk nuclear test site, at ages of 52–63 years old, were performed in 2001–2002. A higher rate of chromosome aberrations was observed in the two contaminated villages, Dolon and Sarjal, compared with the control village,
Kokpekti. Moreover, a relationship of frequency of cells with radiation induced chromosome aberrations and the previously estimated exposure dose was observed. Furthermore, apparent nuclear abnormalities (ANA) of thyroid follicular cells were studied in 30 out of 63 residents, who were examined for chromosome aberrations. A higher rate of ANA was also found in the residents in the exposed villages compared with those in the control village. These results suggest radiation effects both on the chromosomes in
peripheral lymphocytes and on the follicular cells in the thyroid
Nuclear abnormalities in aspirated thyroid cells and chromosome aberrations in lymphocytes of residents near the Semipalatinsk Nuclear Test Site
Chromosomal studies in peripheral lymphocytes from 63 residents near the Semipalatinsk nuclear test site, at ages of 52–63 years old, were performed in 2001–2002. A higher rate of chromosome aberrations was observed in the two contaminated villages, Dolon and Sarjal, compared with the control village,
Kokpekti. Moreover, a relationship of frequency of cells with radiation induced chromosome aberrations and the previously estimated exposure dose was observed. Furthermore, apparent nuclear abnormalities (ANA) of thyroid follicular cells were studied in 30 out of 63 residents, who were examined for chromosome aberrations. A higher rate of ANA was also found in the residents in the exposed villages compared with those in the control village. These results suggest radiation effects both on the chromosomes in
peripheral lymphocytes and on the follicular cells in the thyroid
Development and Test Results of a low- Quadrupole Model for the Large Hadron Collider
A 1-m model of the high gradient 70 mm aperture superconducting low-b quadrupoles for the Large Hadron Collider (LHC) has been developed. A field gradient of 250 T/m at 1.9 K has been achieved with a peak field of 10 T in the coil. This paper describes development of the first model magnet and presents the test results
Measurement of inclusive electron cross section in collisions at TRISTAN
We have studied open charm production in collisions with the
TOPAZ detector at the TRISTAN collider. In this study, charm
quarks were identified by electrons (and positrons) from semi-leptonic decays
of charmed hadrons. The data corresponded to an integrated luminosity of 95.3
pb at a center-of-mass energy of 58 GeV. The results are presented as
the cross sections of inclusive electron production in
collisions with an anti-tag condition, as well as the subprocess cross
sections, which correspond to resolved-photon processes. The latter were
measured by using a sub-sample with remnant jets. A comparison with various
theoretical predictions based on direct and resolved-photon processes showed
that our data prefer that with relatively large gluon contents in a photon at
small , with the next-to-leading order correction, and with a
charm-quark mass of 1.3 GeV.Comment: 26 pages, Latex format (article), 5 figures included, to be published
in Phys. Lett.
A Measurement of the Cross Section in Two-Photon Processes
We have measured the inclusive production cross section in a
two-photon collision at the TRISTAN collider. The mean of
the collider was 57.16 GeV and the integrated luminosity was 150 . The
differential cross section () was obtained in the
range between 1.6 and 6.6 GeV and compared with theoretical predictions, such
as those involving direct and resolved photon processes.Comment: 8 pages, Latex format (article), figures corrected, published in
Phys. Rev. D 50 (1994) 187
Search for Matter-Dependent Atmospheric Neutrino Oscillations in Super-Kamiokande
We consider muon neutrino to tau neutrino oscillations in the context of the
Mass Varying Neutrino (MaVaN) model, where the neutrino mass can vary depending
on the electron density along the flight path of the neutrino. Our analysis
assumes a mechanism with dependence only upon the electron density, hence
ordinary matter density, of the medium through which the neutrino travels.
Fully-contained, partially-contained and upward-going muon atmospheric neutrino
data from the Super--Kamiokande detector, taken from the entire SK--I period of
1489 live days, are compared to MaVaN model predictions. We find that, for the
case of 2-flavor oscillations, and for the specific models tested, oscillation
independent of electron density is favored over density dependence. Assuming
maximal mixing, the best-fit case and the density-independent case do not
differ significantly.Comment: 6 pages, 1 figur
Study of Non-Standard Neutrino Interactions with Atmospheric Neutrino Data in Super-Kamiokande I and II
In this paper we study non-standard neutrino interactions as an example of
physics beyond the standard model using atmospheric neutrino data collected
during the Super-Kamiokande I(1996-2001) and II(2003-2005) periods. We focus on
flavor-changing-neutral-currents (FCNC), which allow neutrino flavor
transitions via neutral current interactions, and effects which violate lepton
non-universality (NU) and give rise to different neutral-current
interaction-amplitudes for different neutrino flavors. We obtain a limit on the
FCNC coupling parameter, varepsilon_{mu tau}, |varepsilon_{mu tau}|<1.1 x
10^{-2} at 90%C.L. and various constraints on other FCNC parameters as a
function of the NU coupling, varepsilon_{e e}. We find no evidence of
non-standard neutrino interactions in the Super-Kamiokande atmospheric data.Comment: 12 Pages, 14 figures. To be submitted to Phys. Rev.
Search for Nucleon Decay into Charged Anti-lepton plus Meson in Super-Kamiokande I and II
Searches for a nucleon decay into a charged anti-lepton (e^+ or {\mu}^+) plus
a light meson ({\pi}^0, {\pi}^-, {\eta}, {\rho}^0, {\rho}^-, {\omega}) were
performed using the Super-Kamiokande I and II data. Twelve nucleon decay modes
were searched for. The total exposure is 140.9 kiloton \cdot years, which
includes a 91.7 kiloton \cdot year exposure (1489.2 live days) of
Super-Kamiokande-I and a 49.2 kiloton \cdot year exposure (798.6 live days) of
Super-Kamiokande-II. The number of candidate events in the data was consistent
with the atmospheric neutrino background expectation. No significant evidence
for a nucleon decay was observed in the data. Thus, lower limits on the nucleon
partial lifetime at 90% confidence level were obtained. The limits range from
3.6 \times 10^31 to 8.2 \times 10^33 years, depending on the decay modes.Comment: 25 pages, 18 figure
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