1,876 research outputs found
Gallium self-interstitial relaxation in Gallium Arsenide: an {ab initio} characterization
Ga interstitials in GaAs () are studied using the local-orbital
{ab-initio} code SIESTA in a supercell of {216+1} atoms. Starting from eight
different initial configurations, we find five metastable structures: the two
tetrahedral sites in addition to the 110-split,
111-split, and 100-split. Studying
the competition between various configuration and charges of , we find
that predominant gallium interstitials in GaAs are charged +1, neutral or at
most -1 depending on doping conditions and prefer to occupy the tetrahedral
configuration where it is surrounded by Ga atoms. Our results are in excellent
agreement with recent experimental results concerning the dominant charge of
, underlining the importance of finite size effects in the calculation
of defects.Comment: v1) 18 pages, 5 figures, submitted to PRB (Latex preprint version)
v2) 9 pages, 5 figures, reviewed version resubmitted to PRB (correction to
equation 1, some changes and reformulations, minor grammatical and typo
corrections, added reference
LOWER EXTREMITY JOINT TORQUE OF TAI CHI GAIT – A PILOT STUDY
INTRODUCTION: Tai Chi is becoming popular among people of all age groups. Although a number of studies have reported the effect of Tai Chi practice on physical fitness [1], the evidence from biomechanical aspect has not been researched sufficiently. To interpret its effect, such as balance and muscle strength, biomechanical information is important. Therefore, the purpose of this study was to obtain information on the biomechanical characteristics of Tai Chi gait (TCG). In this study, TCG was compared to normal walking (NW) to characterize it
Possibility of valence-fluctuation mediated superconductivity in Cd-doped CeIrIn probed by In-NQR
We report on a pressure-induced evolution of exotic superconductivity and
spin correlations in CeIr(InCd) by means of
In-Nuclear-Quadrupole-Resonance (NQR) studies. Measurements of an NQR spectrum
and nuclear-spin-lattice-relaxation rate have revealed that
antiferromagnetism induced by the Cd-doping emerges locally around Cd dopants,
but superconductivity is suddenly induced at = 0.7 and 0.9 K at 2.34 and
2.75 GPa, respectively. The unique superconducting characteristics with a large
fraction of the residual density of state at the Fermi level that increases
with differ from those for anisotropic superconductivity mediated by
antiferromagnetic correlations. By incorporating the pressure dependence of the
NQR frequency pointing to the valence change of Ce, we suggest that
unconventional superconductivity in the CeIr(InCd) system may
be mediated by valence fluctuations.Comment: Accepted for publication in Physical Review Letter
ANALYSIS OF RELATIONSHIP BETWEEN VEGETATION DISTRIBUTION AND LAND PRICE USING MULTITEMPORAL DATA
Japanese cities are facing a rapidly aging society with birthrates, lower than the average rates of developed world. Population decline generates many problems such as depopulation in rural areas. One of the measures implemented is to define core areas for maintaining sufficient population density given current and predicted population dynamics. On the other hand, there is a potential for the surroundings of the core areas to be run-down because vacancies generate many problems such as crime, susceptibility to fire, and other negative events. There have been, however, few measures concerning the spatial distribution of parks and open spaces around the core areas. We applied a hedonic approach with a Geographically Weighted Regression (GWR) to the analysis of the relationship between the assessed values of land and geographical information in order to estimate the importance of landscape factors: the spatial continuity of vegetation distributions, public parks, and the local averages of NDVI. It was shown that the number of points where the spatial continuity of vegetation distributions makes positive impacts on nearby land prices is gradually increasing during years 2000 and 2015, while the average of land price continues to fall
Long-term QiGong practice is associated with improved self-perceived health and quality of life
In cross-sectional studies, we examined the long-term practice effects of QiGong exercise on perceived health and quality of life (QoL) in middle-aged (over 50 years) Japanese individuals. In Study 1, Japanese adults (n = 320) who practised QiGong responded to a questionnaire concerning the perceived benefits of QiGong practice and QoL. In Study 2, we collected data from QiGong participants who attended a QiGong conference (n = 799). Participants in Study 1 perceived that QiGong affords physical, psychological, and social benefits and QiGong duration in years correlated strongly with QoL. In Study 2, those who practised QiGong for 0–3 years vs. 13+ years reported a greater likelihood of perceived palpitation, insomnia, a lack of vigour, and attention deficit (odd ratios 1.56–2.60, all p  .05). QiGong is a multi-component form of physical activity, which – if practised for prolonged periods – affords motor, cognitive, social, and QoL benefits
Leading-Order Actions of Goldstino Fields
This paper starts with a self-contained discussion of the so-called
Akulov-Volkov action S_AV, which is traditionally taken to be the leading-order
action of Goldstino field. Explicit expressions for S_AV and its chiral version
S_AV^ch are presented. We then turn to the issue on how these actions are
related to the leading-order action S_NL proposed in the newly proposed
constrained superfield formalism. We show that S_NL may yield S_AV/S_AV^ch or a
totally different action S_KS, depending on how the auxiliary field in the
former is integrated out. However, S_KS and S_AV/S_AV^ch always yield the same
S-matrix elements, as one would have expected from general considerations in
quantum field theory.Comment: Minor changes, version to appear in European Physical Journal
Target Mass Effects in Polarized Virtual Photon Structure Functions
We study target mass effects in the polarized virtual photon structure
functions , in the kinematic
region , where is the mass squared of
the probe (target) photon. We obtain the expressions for and in closed form by inverting the
Nachtmann moments for the twist-2 and twist-3 operators. Numerical analysis
shows that target mass effects appear at large and become sizable near
, the maximal value of , as the ratio
increases. Target mass effects for the sum rules of and
are also discussed.Comment: 24 pages, LaTeX, 9 eps figure
Virtual photon structure functions and positivity constraints
We study the three positivity constraints among the eight virtual photon
structure functions, derived from the Cauchy-Schwarz inequality and which are
hence model-independent. The photon structure functions obtained from the
simple parton model show quite different behaviors in a massive quark or a
massless quark case, but they satisfy, in both cases, the three positivity
constraints. We then discuss an inequality which holds among the unpolarized
and polarized photon structure functions , and
, in the kinematic region , where is the mass squared of the probe (target) photon, and we examine
whether this inequality is satisfied by the perturbative QCD results.Comment: 24 pages, 13 eps figure
Parton distributions in the virtual photon target up to NNLO in QCD
Parton distributions in the virtual photon target are investigated in
perturbative QCD up to the next-to-next-to-leading order (NNLO). In the case
, where () is the mass squared of the
probe (target) photon, parton distributions can be predicted completely up to
the NNLO, but they are factorisation-scheme-dependent. We analyse parton
distributions in two different factorisation schemes, namely and
schemes, and discuss their scheme dependence. We show that
the factorisation-scheme dependence is characterised by the large-
behaviours of quark distributions. Gluon distribution is predicted to be very
small in absolute value except in the small- region.Comment: 28 pages, 5 figures, version to appear in Eur. Phys. J.
Effects of Single-site Anisotropy on Mixed Diamond Chains with Spins 1 and 1/2
Effects of single-site anisotropy on mixed diamond chains with spins 1 and
1/2 are investigated in the ground states and at finite temperatures. There are
phases where the ground state is a spin cluster solid, i.e., an array of
uncorrelated spin-1 clusters separated by singlet dimers. The ground state is
nonmagnetic for the easy-plane anisotropy, while it is paramagnetic for the
easy-axis anisotropy. Also, there are the N\'eel, Haldane, and large-
phases, where the ground state is a single spin cluster of infinite size and
the system is equivalent to the spin-1 Heisenberg chain with alternating
anisotropy. The longitudinal and transverse susceptibilities and entropy are
calculated at finite temperatures in the spin-cluster-solid phases. Their
low-temperature behaviors are sensitive to anisotropy.Comment: 8 pages, 4 figure
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