13,885 research outputs found
Multiangle observations of Arctic clouds from FIRE ACE: June 3, 1998, case study
In May and June 1998 the Airborne Multiangle Imaging Spectroradiometer (AirMISR) participated in the FIRE Arctic Cloud Experiment (ACE). AirMISR is an airborne instrument for obtaining multiangle imagery similar to that of the satellite-borne MISR instrument. This paper presents a detailed analysis of the data collected on June 3, 1998. In particular, AirMISR radiance measurements are compared with measurements made by two other instruments, the Cloud Absorption Radiometer (CAR) and the MODIS airborne simulator (MAS), as well as to plane-parallel radiative transfer simulations. It is found that the AirMISR radiance measurements and albedo estimates compare favorably both with the other instruments and with the radiative transfer simulations. In addition to radiance and albedo, the multiangle AirMISR data can be used to obtain estimates of cloud top height using stereoimaging techniques. Comparison of AirMISR retrieved cloud top height (using the complete MISR-based stereoimaging approach) shows excellent agreement with the measurements from the airborne Cloud Lidar System (CLS) and ground-based millimeterwave cloud radar
Gravitational coupling of neutrinos in a medium
In a medium that contains electrons but not the other charged leptons, such
as normal matter, the gravitational interactions of neutrinos are not the same
for all the neutrino flavors. We calculate the leading order matter-induced
corrections to the neutrino gravitational interactions in such a medium and
consider some of their physical implications.Comment: 21 pages, Latex, uses axodraw.sty (typos corrected; two references
added. To appear in Phys. Rev. D
Autonomous and controlled motivational regulations for multiple health related behaviors: between- and within-participants analyses
Self-determination theory has been applied to the prediction of a number of health-related behaviors with self-determined or autonomous forms of motivation generally more effective in predicting health behavior than non-self-determined or controlled forms. Research has been confined to examining the motivational predictors in single health behaviors rather than comparing effects across multiple behaviors. The present study addressed this gap in the literature by testing the relative contribution of autonomous and controlling motivation to the prediction of a large number of health-related behaviors, and examining individual differences in self-determined motivation as a moderator of the effects of autonomous and controlling motivation on health behavior. Participants were undergraduate students (N = 140) who completed measures of autonomous and controlled motivational regulations and behavioral intention for 20 health-related behaviors at an initial occasion with follow-up behavioral measures taken four weeks later. Path analysis was used to test a process model for each behavior in which motivational regulations predicted behavior mediated by intentions. Some minor idiosyncratic findings aside, between-participants analyses revealed significant effects for autonomous motivational regulations on intentions and behavior across the 20 behaviors. Effects for controlled motivation on intentions and behavior were relatively modest by comparison. Intentions mediated the effect of autonomous motivation on behavior. Within-participants analyses were used to segregate the sample into individuals who based their intentions on autonomous motivation (autonomy-oriented) and controlled motivation (control-oriented). Replicating the between-participants path analyses for the process model in the autonomy- and control-oriented samples did not alter the relative effects of the motivational orientations on intention and behavior. Results provide evidence for consistent effects of autonomous motivation on intentions and behavior across multiple health-related behaviors with little evidence of moderation by individual differences. Findings have implications for the generalizability of proposed effects in self-determination theory and intentions as a mediator of distal motivational factors on health-related behavior
Deformed Special Relativity and Deformed Symmetries in a Canonical Framework
In this paper we have studied the nature of kinematical and dynamical laws in
-Minkowski spacetime from a new perspective: the canonical phase space
approach. We discuss a particular form of -Minkowski phase space
algebra that yields the -extended finite Lorentz transformations
derived in \cite{kim}. This is a particular form of a Deformed Special
Relativity model that admits a modified energy-momentum dispersion law as well
as noncommutative -Minkowski phase space. We show that this system can
be completely mapped to a set of phase space variables that obey canonical (and
{\it{not}} -Minkowski) phase space algebra and Special Relativity
Lorentz transformation (and {\it{not}} -extended Lorentz
transformation). The complete set of deformed symmetry generators are
constructed that obeys an unmodified closed algebra but induce deformations in
the symmetry transformations of the physical -Minkowski phase space
variables. Furthermore, we demonstrate the usefulness and simplicity of this
approach through a number of phenomenological applications both in classical
and quantum mechanics. We also construct a Lagrangian for the
-particle.Comment: Revised version with change in Title and Abstract, No change in
mathematical content, Reference section enlarged, Discussion on Soccer Ball
Problem removed; Version to appear in PR
Public exhibit for demonstrating the quantum of electrical conductance
We present a new robust setup that explains and demonstrates the quantum of
electrical conductance for a general audience and which is continuously
available in a public space. The setup allows users to manually thin a gold
wire of several atoms in diameter while monitoring its conductance in real
time. During the experiment, a characteristic step-like conductance decrease
due to rearrangements of atoms in the cross-section of the wire is observed.
Just before the wire breaks, a contact consisting of a single atom with a
characteristic conductance close to the quantum of conductance can be
maintained up to several seconds. The setup is operated full-time, needs
practically no maintenance and is used on different educational levels
Scale-Dependent Price Fluctuations for the Indian Stock Market
Classic studies of the probability density of price fluctuations for
stocks and foreign exchanges of several highly developed economies have been
interpreted using a {\it power-law} probability density function with exponent values , which are outside the
L\'evy-stable regime . To test the universality of this
relationship for less highly developed economies, we analyze daily returns for
the period Nov. 1994--June 2002 for the 49 largest stocks of the National Stock
Exchange which has the highest volume of trade in India. We find that
decays as an {\it exponential} function with a
characteristic decay scales for the negative tail and
for the positive tail, which is significantly different
from that observed for developed economies. Thus we conclude that the Indian
stock market may belong to a universality class that differs from those of
developed countries analyzed previously.Comment: 7 pages, 8 figure
Chaos modified wall formula damping of the surface motion of a cavity undergoing fissionlike shape evolutions
The chaos weighted wall formula developed earlier for systems with partially
chaotic single particle motion is applied to large amplitude collective motions
similar to those in nuclear fission. Considering an ideal gas in a cavity
undergoing fission-like shape evolutions, the irreversible energy transfer to
the gas is dynamically calculated and compared with the prediction of the chaos
weighted wall formula. We conclude that the chaos weighted wall formula
provides a fairly accurate description of one body dissipation in dynamical
systems similar to fissioning nuclei. We also find a qualitative similarity
between the phenomenological friction in nuclear fission and the chaos weighted
wall formula. This provides further evidence for one body nature of the
dissipative force acting in a fissioning nucleus.Comment: 8 pages (RevTex), 7 Postscript figures, to appear in Phys.Rev.C.,
Section I (Introduction) is modified to discuss some other works (138 kb
Proton Decay and Related Processes in Unified Models with Gauged Baryon Number:
In unification models based on SU(15) or SU(16), baryon number is part of the
gauge symmetry, broken spontaneously. In such models, we discuss various
scenarios of important baryon number violating processes like proton decay and
neutron-antineutron oscillation. Our analysis depends on the effective operator
method, and covers many variations of symmetry breaking, including different
intermediate groups and different Higgs boson content. We discuss processes
mediated by gauge bosons and Higgs bosons parallely. We show how accidental
global or discrete symmetries present in the full gauge invariant Lagrangian
restrict baryon number violating processes in these models. In all cases, we
find that baryon number violating interactions are sufficiently suppressed to
allow grand unification at energies much lower than the usual GeV.Comment: (32 pages LATEX) [DOE-ER\,40757-022, CPP-93-22] {Small changes made
and two references added. This version will appear in Phys. Rev. D
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