2,718 research outputs found
Transference in spaces of measures
The transference theory for Lp spaces of Calderon, Coifman, and Weiss is a
powerful tool with many applications to singular integrals, ergodic theory, and
spectral theory of operators. Transference methods afford a unified approach to
many problems in diverse areas, which before were proved by a variety of
methods. The purpose of this paper is to bring about a similar approach to the
study of measures. Specifically, deep results in classical harmonic analysis
and ergodic theory, due to Bochner, de Leeuw-Glicksberg, Forelli, and others,
are all extensions of the classical F.&M. Riesz Theorem. We will show that all
these extensions are obtainable via our new transference principle for spaces
of measures.Comment: Also available at http://www.math.missouri.edu/~stephen/preprints
Comparison among Various Expressions of Complex Admittance for Quantum System in Contact with Heat Reservoir
Relation among various expressions of the complex admittance for quantum
systems in contact with heat reservoir is studied. Exact expressions of the
complex admittance are derived in various types of formulations of equations of
motion under contact with heat reservoir. Namely, the complex admittance is
studied in the relaxation method and the external-field method. In the former
method, the admittance is calculated using the Kubo formula for quantum systems
in contact with heat reservoir in no external driving fields, while in the
latter method the admittance is directly calculated from equations of motion
with external driving terms. In each method, two types of equation of motions
are considered, i.e., the time-convolution (TC) equation and
time-convolutionless (TCL) equation. That is, the full of the four cases are
studied. It is turned out that the expression of the complex admittance
obtained by using the relaxation method with the TC equation exactly coincides
with that obtained by using the external-field method with the TC equation,
while other two methods give different forms. It is also explicitly
demonstrated that all the expressions of the complex admittance coincide with
each other in the lowest Born approximation for the systemreservoir
interaction. The formulae necessary for the higher order expansions in powers
of the system-reservoir interaction are derived, and also the expressions of
the admittance in the n-th order approximation are given. To characterize the
TC and TCL methods, we study the expressions of the admittances of two exactly
solvable models. Each exact form of admittance is compared with the results of
the two methods in the lowest Born approximation. It is found that depending on
the model, either of TC and TCL would be the better method.Comment: 34pages, no figur
Carbon storage and DNA absorption in allophanic soils and paleosols
Andisols and andic paleosols dominated by the nanocrystalline mineral allophane sequester large amounts of carbon (C), attributable mainly to its chemical bonding with charged hydroxyl groups on the surface of allophane together with its physical protection in nanopores within and between allophane nanoaggregates. C near-edge X-ray absorption fine structure (NEXAFS) spectra for a New Zealand Andisol (Tirau series) showed that the organic matter (OM) mainly comprises quinonic, aromatic, aliphatic, and carboxylic C. In different buried horizons from several other Andisols, C contents varied but the C species were similar, attributable to pedogenic processes operating during developmental upbuilding, downward leaching, or both. The presence of OM in natural allophanic soils weakened the adsorption of DNA on clay; an adsorption isotherm experiment involving humic acid (HA) showed that HA-free synthetic allophane adsorbed seven times more DNA than HA-rich synthetic allophane. Phosphorus X-ray absorption near-edge structure (XANES) spectra for salmonsperm DNA and DNA-clay complexes indicated that DNA was bound to the allophane clay through the phosphate group, but it is not clear if DNA was chemically bound to the surface of the allophane or to OM, or both. We plan more experiments to investigate interactions among DNA, allophane (natural and synthetic), and OM. Because DNA shows a high affinity to allophane, we are studying the potential to reconstruct late Quaternary palaeoenvironments by attempting to extract and characterise ancient DNA from allophanic paleosol
Enabling Personalized Composition and Adaptive Provisioning of Web Services
The proliferation of interconnected computing devices is fostering the emergence of environments where Web services made available to mobile users are a commodity. Unfortunately, inherent limitations of mobile devices still hinder the seamless access to Web services, and their use in supporting complex user activities. In this paper, we describe the design and implementation of a distributed, adaptive, and context-aware framework for personalized service composition and provisioning adapted to mobile users. Users specify their preferences by annotating existing process templates, leading to personalized service-based processes. To cater for the possibility of low bandwidth communication channels and frequent disconnections, an execution model is proposed whereby the responsibility of orchestrating personalized processes is spread across the participating services and user agents. In addition, the execution model is adaptive in the sense that the runtime environment is able to detect exceptions and react to them according to a set of rules
Indication of antiferromagnetic interaction between paramagnetic Co ions in the diluted magnetic semiconductor ZnCoO
The magnetic properties of ZnCoO ( and 0.10) thin films,
which were homo-epitaxially grown on a ZnO(0001) substrates with varying
relatively high oxygen pressure, have been investigated using x-ray magnetic
circular dichroism (XMCD) at Co core-level absorption edge. The line
shapes of the absorption spectra are the same in all the films and indicate
that the Co ions substitute for the Zn sites. The magnetic-field and
temperature dependences of the XMCD intensity are consistent with the
magnetization measurements, indicating that except for Co there are no
additional sources for the magnetic moment, and demonstrate the coexistence of
paramagnetic and ferromagnetic components in the homo-epitaxial
ZnCoO thin films, in contrast to the ferromagnetism in the
hetero-epitaxial ZnCoO films studied previously. The analysis of
the XMCD intensities using the Curie-Weiss law reveals the presence of
antiferromagnetic interaction between the paramagnetic Co ions. Missing XMCD
intensities and magnetization signals indicate that most of Co ions are
non-magnetic probably because they are strongly coupled antiferromagnetically
with each other. Annealing in a high vacuum reduces both the paramagnetic and
ferromagnetic signals. We attribute the reductions to thermal diffusion and
aggregation of Co ions with antiferromagnetic nanoclusters in
ZnCoO.Comment: 21 pages, 7 figures, accepted for Physical Review
Dissociated Oxygen Consumption and Carbon Dioxide Production in the Post-Cardiac Arrest Rat: A Novel Metabolic Phenotype.
BACKGROUND: The concept that resuscitation from cardiac arrest (CA) results in a metabolic injury is broadly accepted, yet patients never receive this diagnosis. We sought to find evidence of metabolic injuries after CA by measuring O
METHODS AND RESULTS: Rats were anesthetized and randomized into 3 groups: resuscitation from 10-minute asphyxia with inhaled 100% O
CONCLUSIONS: CA altered cellular metabolism resulting in increased V
Soft x-ray magnetic circular dichroism study of weakly ferromagnetic ZnVO thin film
We performed a soft x-ray magnetic circular dichroism (XMCD) study of a
ZnVO thin film which showed small ferromagnetic moment. Field and
temperature dependences of V 2 XMCD signals indicated the coexistence of
Curie-Weiss paramagnetic, antiferromagnetic, and possibly ferromagnetic V ions,
quantitatively consistent with the magnetization measurements. We attribute the
paramagnetic signal to V ions substituting Zn sites which are somewhat
elongated along the c-axis
- …