675 research outputs found
Variants of transcription factor 7-like 2 (TCF7L2) gene and incident glucose intolerance in Japanese-Brazilians
Common variants of the transcription factor 7-like 2 (TCF7L2) gene have been found to be associated with type 2 diabetes in different ethnic groups. The Japanese-Brazilian population has one of the highest prevalence rates of diabetes. Therefore, the aim of the present study was to assess whether two single-nucleotide polymorphisms (SNPs) of TCF7L2, rs7903146 and rs12255372, could predict the development of glucose intolerance in Japanese-Brazilians. In a population-based 7-year prospective study, we genotyped 222 individuals (72 males and 150 females, aged 56.2 ± 10.5 years) with normal glucose tolerance at baseline. In the study population, we found that the minor allele frequency was 0.05 for SNP rs7903146 and 0.03 for SNP rs12255372. No significant allele or genotype association with glucose intolerance incidence was found for either SNP. Haplotypes were constructed with these two SNPs and three haplotypes were defined: CG (frequency: 0.94), TT (frequency = 0.027) and TG (frequency = 0.026). None of the haplotypes provided evidence for association with the incidence of glucose intolerance. Despite no associations between incidence of glucose intolerance and SNPs of the TCF7L2 gene in Japanese-Brazilians, we found that carriers of the CT genotype for rs7903146 had significantly lower insulin levels 2 h after a 75-g glucose load than carriers of the CC genotype. In conclusion, in Japanese-Brazilians, a population with a high prevalence of type 2 diabetes, common TCF7L2 variants did not make major contributions to the incidence of glucose tolerance abnormalities
Measurement of the solar 8B neutrino rate with a liquid scintillator target and 3 MeV energy threshold in the Borexino detector
We report the measurement of electron neutrino elastic scattering from 8B
solar neutrinos with 3 MeV energy threshold by the Borexino detector in Gran
Sasso (Italy). The rate of solar neutrino-induced electron scattering events
above this energy in Borexino is 0.217 +- 0.038 (stat) +- 0.008 (syst) cpd/100
t, which corresponds to the equivalent unoscillated flux of (2.4 +- 0.4 (stat)
+- 0.1 (syst))x10^6 cm^-2 s^-1, in good agreement with measurements from SNO
and SuperKamiokaNDE. Assuming the 8B neutrino flux predicted by the high
metallicity Standard Solar Model, the average 8B neutrino survival probability
above 3 MeV is measured to be 0.29+-0.10. The survival probabilities for 7Be
and 8B neutrinos as measured by Borexino differ by 1.9 sigma. These results are
consistent with the prediction of the MSW-LMA solution of a transition in the
solar electron neutrino survival probability between the low energy
vacuum-driven and the high-energy matter-enhanced solar neutrino oscillation
regimes.Comment: 10 pages, 8 figures, 6 table
Pulse-Shape discrimination with the Counting Test Facility
Pulse shape discrimination (PSD) is one of the most distinctive features of
liquid scintillators. Since the introduction of the scintillation techniques in
the field of particle detection, many studies have been carried out to
characterize intrinsic properties of the most common liquid scintillator
mixtures in this respect. Several application methods and algorithms able to
achieve optimum discrimination performances have been developed. However, the
vast majority of these studies have been performed on samples of small
dimensions. The Counting Test Facility, prototype of the solar neutrino
experiment Borexino, as a 4 ton spherical scintillation detector immersed in
1000 tons of shielding water, represents a unique opportunity to extend the
small-sample PSD studies to a large-volume setup. Specifically, in this work we
consider two different liquid scintillation mixtures employed in CTF,
illustrating for both the PSD characterization results obtained either with the
processing of the scintillation waveform through the optimum Gatti's method, or
via a more conventional approach based on the charge content of the
scintillation tail. The outcomes of this study, while interesting per se, are
also of paramount importance in view of the expected Borexino detector
performances, where PSD will be an essential tool in the framework of the
background rejection strategy needed to achieve the required sensitivity to the
solar neutrino signals.Comment: 39 pages, 17 figures, submitted to Nucl. Instr. Meth.
Impact of interaction between chronic variable stress and moderate intensity physical exercise on antibody production in Wistar rats
Stress in its chronic form has been an important factor in the onset of depression. In addition, it can lead to immunosuppression. On the other hand, physical exercise has a protective action on the immune system and reduces the signs and symptoms of stress. Studies on the effects of chronic variable stress (CVS) and moderate intensity physical exercise (MIPE) on humoral immunity are scarce. Thus, in this study, we investigated the interaction between the effects of CVS and MIPE on antibody production. Wistar rats were divided into four groups: control (C); physical exercise (P); stress (S); and physical exercise and stress (PS). The P and PS groups were trained in MIPE for six weeks. From the fourth week of the study, concomitant with the MIPE, the S and PS groups were subjected to CVS. To evaluate the production of antibodies, all groups were immunized. Regarding antibody production, it was observed that females in the C and S groups presented higher IgM antibody production in relation to males. Furthermore, the production of IgM was potentiated in males of the PS group. On the other hand, no significant differences were observed in relation to the production of IgG1 and IgG2a. We conclude that CVS prevented the increase in IgM production in male rats and MIPE was effective in reversing the effects of stress on the production of IgM in male rats. On the other hand, the production of IgG1 and IgG2a was not affected by MIPE or CVS
Interstellar MHD Turbulence and Star Formation
This chapter reviews the nature of turbulence in the Galactic interstellar
medium (ISM) and its connections to the star formation (SF) process. The ISM is
turbulent, magnetized, self-gravitating, and is subject to heating and cooling
processes that control its thermodynamic behavior. The turbulence in the warm
and hot ionized components of the ISM appears to be trans- or subsonic, and
thus to behave nearly incompressibly. However, the neutral warm and cold
components are highly compressible, as a consequence of both thermal
instability in the atomic gas and of moderately-to-strongly supersonic motions
in the roughly isothermal cold atomic and molecular components. Within this
context, we discuss: i) the production and statistical distribution of
turbulent density fluctuations in both isothermal and polytropic media; ii) the
nature of the clumps produced by thermal instability, noting that, contrary to
classical ideas, they in general accrete mass from their environment; iii) the
density-magnetic field correlation (or lack thereof) in turbulent density
fluctuations, as a consequence of the superposition of the different wave modes
in the turbulent flow; iv) the evolution of the mass-to-magnetic flux ratio
(MFR) in density fluctuations as they are built up by dynamic compressions; v)
the formation of cold, dense clouds aided by thermal instability; vi) the
expectation that star-forming molecular clouds are likely to be undergoing
global gravitational contraction, rather than being near equilibrium, and vii)
the regulation of the star formation rate (SFR) in such gravitationally
contracting clouds by stellar feedback which, rather than keeping the clouds
from collapsing, evaporates and diperses them while they collapse.Comment: 43 pages. Invited chapter for the book "Magnetic Fields in Diffuse
Media", edited by Elisabete de Gouveia dal Pino and Alex Lazarian. Revised as
per referee's recommendation
Measurement of CNGS muon neutrino speed with Borexino
We have measured the speed of muon neutrinos with the Borexino detector using
short-bunch CNGS beams. The final result for the difference in time-of-flight
between a =17 GeV muon neutrino and a particle moving at the speed of light
in vacuum is {\delta}t = 0.8 \pm 0.7stat \pm 2.9sys ns, well consistent with
zero.Comment: 6 pages, 5 figure
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Observation of Geo-Neutrinos
Geo-neutrinos, electron anti-neutrinos produced in beta decays of naturally
occurring radioactive isotopes in the Earth, are a unique direct probe of our
planet's interior. We report the first observation at more than 3 C.L.
of geo-neutrinos, performed with the Borexino detector at Laboratori Nazionali
del Gran Sasso. Anti-neutrinos are detected through the neutron inverse beta
decay reaction. With a 252.6 ton-yr fiducial exposure after all selection cuts,
we detected 9.9^{+4.1}_{-3.4}(^{+14.6}_{-8.2}) geo-neutrino events, with errors
corresponding to a 68.3%(99.73%) C.L. From the profile, the
statistical significance of the Borexino geo-neutrino observation corresponds
to a 99.997% C.L. Our measurement of the geo-neutrinos rate is
3.9^{+1.6}_{-1.3}(^{+5.8}_{-3.2}) events/(100ton-yr). This measurement rejects
the hypothesis of an active geo-reactor in the Earth's core with a power above
3 TW at 95% C.L. The observed prompt positron spectrum above 2.6 MeV is
compatible with that expected from european nuclear reactors (mean base line of
approximately 1000 km). Our measurement of reactor anti-neutrinos excludes the
non-oscillation hypothesis at 99.60% C.L.Comment: 8 pages, 4 figures, 3 table
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