22,178 research outputs found
The Scaling Behavior of Classical Wave Transport in Mesoscopic Media at the Localization Transition
The propagation of classical wave in disordered media at the Anderson
localization transition is studied. Our results show that the classical waves
may follow a different scaling behavior from that for electrons. For electrons,
the effect of weak localization due to interference of recurrent scattering
paths is limited within a spherical volume because of electron-electron or
electron-phonon scattering, while for classical waves, it is the sample
geometry that determine the amount of recurrent scattering paths that
contribute. It is found that the weak localization effect is weaker in both
cubic and slab geometry than in spherical geometry. As a result, the averaged
static diffusion constant D(L) scales like ln(L)/L in cubic or slab geometry
and the corresponding transmission follows ~ln L/L^2. This is in contrast
to the behavior of D(L)~1/L and ~1/L^2 obtained previously for electrons
or spherical samples. For wave dynamics, we solve the Bethe-Salpeter equation
in a disordered slab with the recurrent scattering incorporated in a
self-consistent manner. All of the static and dynamic transport quantities
studied are found to follow the scaling behavior of D(L). We have also
considered position-dependent weak localization effects by using a plausible
form of position-dependent diffusion constant D(z). The same scaling behavior
is found, i.e., ~ln L/L^2.Comment: 11 pages, 12 figures. Submitted to Phys. Rev. B on 3 May 200
Unparticle physics and lepton flavor violating radion decays in the Randall-Sundrum scenario
We predict the branching ratios of the lepton flavor violating radion decays
r -> e^{\pm} \mu^{\pm}, r -> e^{\pm} \tau^{\pm} and r ->\mu^{\pm} \tau^{\pm} in
the framework of the Randall-Sundrum scenario that the lepton flavor violation
is carried by the scalar unparticle mediation. We observe that their BRs are
strongly sensitive to the unparticle scaling dimension and, for its small
values, the branching ratios can reach to the values of the order of 10^{-8},
for the heavy lepton flavor case.Comment: 21 pages, 11 Figures, 1 Tabl
Landau diamagnetism and magnetization of interacting diffusive conductors
We show how the orbital magnetization of an interacting disordered diffusive
electron gas can be simply related to the magnetization of the non-interacting
system having the same geometry. This result is applied to the persistent
current of a mesoscopic ring and to the relation between Landau diamagnetism
and the interaction correction to the magnetization of diffusive systems. The
field dependence of this interaction contribution can be deduced directly from
the de Haas-van Alphen oscillations of the free electron gas. Known results for
the free orbital magnetism of finite systems can be used to derive the
interaction contribution in the diffusive regime in various geometries.Comment: 4 pages, 2 figure
Structure of a liquid crystalline fluid around a macroparticle: Density functional theory study
The structure of a molecular liquid, in both the nematic liquid crystalline
and isotropic phases, around a cylindrical macroparticle, is studied using
density functional theory. In the nematic phase the structure of the fluid is
highly anisotropic with respect to the director, in agreement with results from
simulation and phenomenological theories. On going into the isotropic phase the
structure becomes rotationally invariant around the macroparticle with an
oriented layer at the surface.Comment: 10 pages, 6 figues. Submitted to Phys. Rev.
Are Asians comfortable with discussing death in health valuation studies? A study in multi-ethnic Singapore
BACKGROUND
To characterize ease in discussing death (EID) and its influence on health valuation in a multi-ethnic Asian population and to determine the acceptability of various descriptors of death and "pits"/"all-worst" in health valuation.
METHODS
In-depth interviews (English or mother-tongue) among adult Chinese, Malay and Indian Singaporeans selected to represent both genders and a wide range of ages/educational levels. Subjects rated using 0–10 visual analogue scales (VAS): (1) EID, (2) acceptability of 8 descriptors for death, and (3) appropriateness of "pits" and "all-worst" as descriptors for the worst possible health state. Subjects also valued 3 health states using VAS followed by time trade-off (TTO). The influence of sociocultural variables on EID and these descriptors was studied using univariable analyses and multiple linear regression (MLR). The influence of EID on VAS/TTO utilities with adjustment for sociocultural variables was assessed using MLR.
RESULTS
Subjects (n = 63, 35% Chinese, 32% Malay, median age 44 years) were generally comfortable with discussing death (median EID: 8.0). Only education significantly influenced EID (p = 0.045). EID correlated weakly with VAS/TTO scores (range: VAS: -0.23 to 0.07; TTO: -0.14 to 0.11). All subjects felt "passed away", "departed" and "deceased" were most acceptable (median acceptability: 8.0) while "sudden death" and "immediate death" were least acceptable (median acceptability: 5.0). Subjects clearly preferred "all-worst" to "pits" (63% vs. 19%, p < 0.001).
CONCLUSION
Singaporeans were generally comfortable with discussing death and had clear preferences for several descriptors of death and for "all-worst". EID is unlikely to influence health preference measurement in health valuation studies
What is the Thouless Energy for Ballistic Systems?
The Thouless energy, \Ec characterizes numerous quantities associated with
sensitivity to boundary conditions in diffusive mesoscopic conductors. What
happens to these quantities if the disorder strength is decreased and a
transition to the ballistic regime takes place? In the present analysis we
refute the intuitively plausible assumption that \Ec loses its meaning as an
inverse diffusion time through the system at hand, and generally disorder
independent scales take over. Instead we find that a variety of (thermodynamic)
observables are still characterized by the Thouless energy.Comment: 4 pages REVTEX, uuencoded file. To appear in Physical Review Letter
Improving coastal livelihoods through sustainable aquaculture practices - a report to the collaborative APEC Grouper Research and Development Network
Wild-harvest fisheries for live reef fish are largely over-exploited or unsustainable because of over-fishing and the widespread use of destructive fishing practices such as blast and cyanide fishing. Sustainable aquaculture – such as that of groupers – is one option for meeting the
strong demand for reef fish, as well as potentially maintaining or improving the livelihoods of coastal communities. This report from a short study by the STREAM Initiative draws on secondary literature, media sources and four diverse case studies from at-risk reef fisheries, to frame a strategy for encouraging sustainable aquaculture as an alternative to destructive fishing practices. It was undertaken as a component of the APEC-funded project Collaborative Grouper Research and Development Network (FWG/01/2001) to better understand how recent technical advances in grouper culture and other complementary work – including that of the Asia-Pacific Marine Finfish Aquaculture Network (APMFAN) hosted by NACA – could better support the livelihoods of poor coastal communities. (PDF contains 49 pages
Klein Levin syndrome is a steroid-responsive, non-N-methyl-D-aspartate receptor-mediated encephalitis
Poster SessionBACKGROUND: Klein Levin syndrome is a rare neuropsychiatric disorder with periodic hypersomnia, cognitive and behavioural disturbance. It is postulated to be triggered by a viral illness or is a postinfectious immune-mediated encephalitis. With an increasing awareness of immune-med...published_or_final_versio
Comparison of chemical profiles and effectiveness between Erxian decoction and mixtures of decoctions of its individual herbs : a novel approach for identification of the standard chemicals
Acknowledgements This study was partially supported by grants from the Seed Funding Programme for Basic Research (Project Number 201211159146 and 201411159213), the University of Hong Kong. We thank Mr Keith Wong and Ms Cindy Lee for their technical assistances.Peer reviewedPublisher PD
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