1,058 research outputs found
Entropy change at the martensitic transformation in ferromagnetic shape memory alloys Ni_{2+x}Mn_{1-x}Ga
The entropy change between the high-temperature cubic phase and
the low-temperature tetragonally-based martensitic phase of
NiMnGa () alloys was studied. The experimental
results obtained indicate that in the NiMnGa alloys
increases with the Ni excess . The increase of is presumably
accounted for by an increase of magnetic contribution to the entropy change. It
is suggested that the change in modulation of the martensitic phase of
NiMnGa results in discontinuity of the composition dependence
of .Comment: presented at MMM-47, to be published in J. Appl. Phys. (May 15, 2003
Vitamin Dietary Supplement: Changes and Challenges with the New ANVISA Regulations
In July 2018, the Brazilian National Health Surveillance Agency (Agência Nacional de Vigilância Sanitária, ANVISA, in Portuguese) published new regulations for food supplements, leading to changes both in the sales denomination and labeling statements, and in the composition of these products. Among dietary supplements, those containing vitamins are the most consumed by the population. The objective of the present work is to discuss the changes in the parameters established for the products containing vitamins, mainly in relation to the required and allowed concentrations of micronutrients, and to verify the impact of these changes for the population since the publication of the new standards. Until July 2018, vitamin-based products containing between 15% and 100% of the recommended daily intake (RDI) of these micronutrients were classified as vitamin supplements; above this dosage, they were considered medicines. The new legislation changed the minimum and maximum limits allowed for vitamin food supplements. Taking into account the maximum vitamin limits established for adults, the most relevant differences were the increase in these limits in a proportion of 100, 76 and 43 times in regarding vitamins E, B6 and C respectively, when compared to those previously established. For the required minimum limits, the major difference was observed for vitamin D, with a four-fold increase in its concentration. In conclusion, changes in legislation can influence the health of the population, so the ideal amounts of vitamin in supplements and the recommendation to consume these products require extensive discussion and reflection
Development and operational experience of magnetic horn system for T2K experiment
A magnetic horn system to be operated at a pulsed current of 320 kA and to
survive high-power proton beam operation at 750 kW was developed for the T2K
experiment. The first set of T2K magnetic horns was operated for over 12
million pulses during the four years of operation from 2010 to 2013, under a
maximum beam power of 230 kW, and protons were exposed to
the production target. No significant damage was observed throughout this
period. This successful operation of the T2K magnetic horns led to the
discovery of the oscillation phenomenon in 2013 by
the T2K experiment. In this paper, details of the design, construction, and
operation experience of the T2K magnetic horns are described.Comment: 22 pages, 40 figures, also submitted to Nuclear Instrument and
Methods in Physics Research,
Search for Cosmic-Ray Antideuterons
We performed a search for cosmic-ray antideuterons using data collected
during four BESS balloon flights from 1997 to 2000. No candidate was found. We
derived, for the first time, an upper limit of 1.9E-4 (m^2 s sr
GeV/nucleon)^(-1) for the differential flux of cosmic-ray antideuterons, at the
95% confidence level, between 0.17 and 1.15 GeV/nucleon at the top of the
atmosphere.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let
Constraining Supersymmetry
We review constraints on the minimal supersymmetric extension of the Standard
Model (MSSM) coming from direct searches at accelerators such as LEP, indirect
measurements such as b -> s gamma decay and the anomalous magnetic moment of
the muon. The recently corrected sign of pole light-by-light scattering
contributions to the latter is taken into account. We combine these constraints
with those due to the cosmological density of stable supersymmetric relic
particles. The possible indications on the supersymmetric mass scale provided
by fine-tuning arguments are reviewed critically. We discuss briefly the
prospects for future accelerator searches for supersymmetry.Comment: 21 LaTeX pages, 9 eps figures, Invited Contribution to the New
Journal of Physics Focus Issue on Supersymmetr
Precision Measurement of Cosmic-Ray Antiproton Spectrum
The energy spectrum of cosmic-ray antiprotons has been measured in the range
0.18 to 3.56 GeV, based on 458 antiprotons collected by BESS in recent
solar-minimum period. We have detected for the first time a distinctive peak at
2 GeV of antiprotons originating from cosmic-ray interactions with the
interstellar gas. The peak spectrum is reproduced by theoretical calculations,
implying that the propagation models are basically correct and that different
cosmic-ray species undergo a universal propagation. Future BESS flights toward
the solar maximum will help us to study the solar modulation and the
propagation in detail and to search for primary antiproton components.Comment: REVTeX, 4 pages including 4 eps figure
Charmless Hadronic Two-Body B Meson Decays
We report the results of a study of two-body B meson decays to the complete
set of K pi, pi pi, and K K final states. The study is performed on a data
sample of 31.7 +/- 0.3 million B B-bar events recorded on the Upsilon(4S)
resonance by the Belle experiment at KEKB. We observe significant signals in
all K pi final states and in the pi+ pi- and pi+ pi0 final states. We set
limits on the pi0 pi0 and K K final states. A search is performed for
partial-rate asymmetries between conjugate states for flavor-specific final
states.Comment: Submitted to PR
Improved Measurement of the Partial-Rate CP Asymmetry in B+ -> K0pi+ and B- -> K0bar pi- Decays
We report an improved measurement of the partial-rate CP asymmetry in B+ =>
K0pi+ and B- => K0bar pi- decays. The analysis is based on a data sample of 85
million BBbar pairs collected at the Upsilon(4S) resonance with the Belle
detector at the KEKB e+ e- storage ring. We measure Acp(K0pi+-) = 0.07^{+0.09
+0.01}_{-0.08 -0.03}, where the first and second errors are statistical and
systematic, respectively; the corresponding 90% confidence-level interval is
-0.10 < Acp(K0pi+-) < 0.22 .Comment: 7 pages, 8 figures, submitted to Phys. Rev.
Ferromagnetism in semiconductors and oxides: prospects from a ten years' perspective
Over the last decade the search for compounds combining the resources of
semiconductors and ferromagnets has evolved into an important field of
materials science. This endeavour has been fuelled by continual demonstrations
of remarkable low-temperature functionalities found for ferromagnetic
structures of (Ga,Mn)As, p-(Cd,Mn)Te, and related compounds as well as by ample
observations of ferromagnetic signatures at high temperatures in a number of
non-metallic systems. In this paper, recent experimental and theoretical
developments are reviewed emphasising that, from the one hand, they disentangle
many controversies and puzzles accumulated over the last decade and, on the
other, offer new research prospects.Comment: review, 13 pages, 8 figures, 109 reference
Evidence for CP-Violating Asymmetries in B0->pi+pi- Decays and Constraints on the CKM Angle phi2
We present an improved measurement of CP-violating asymmetries in B0 -> pi+
pi- decays based on a 78 fb^-1 data sample collected at the Y(4S) resonance
with the Belle detector at the KEKB asymmetric-energy e+e- collider. We
reconstruct one neutral B meson as a B0 -> pi+ pi- CP eigenstate and identify
the flavor of the accompanying B meson from inclusive properties of its decay
products. We apply an unbinned maximum likelihood fit to the distribution of
the time intervals between the two B meson decay points. The fit yields the
CP-violating asymmetry amplitudes Apipi = +0.77+/-0.27(stat)+/-0.08(syst) and
Spipi = -1.23+/-0.41(stat)+0.08/-0.07(syst), where the statistical
uncertainties are determined from Monte Carlo pseudo-experiments. We obtain
confidence intervals for CP-violating asymmetry parameters Apipi and Spipi
based on a frequentist approach. We rule out the CP-conserving case,
Apipi=Spipi=0, at the 99.93% confidence level. We discuss how these results
constrain the value of the CKM angle phi2.Comment: 26 pages, 13 figures, submitted to Phys. Rev.
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