725 research outputs found
Measurement of high-order polarization mode dispersion
We demonstrate a new method to measure high-order polarization mode dispersion (PMD) using the Jones matrix exponential expansion. High-order PMD is characterized by measuring a series of characteristic matrices, which are convenient quantities for analyzing PMD effects in the time-domain. An experimental method is developed to estimate the validity range of the exponential expansion
Polarization mode dispersion in radio-frequency interferometric embedded fiber-optic sensors
The effect of fiber birefringence on the propagation delay in an embedded fiber-optic strain sensor is studied. The polarization characteristics of the sensor are described in terms of polarization mode dispersion through the principal states of polarization and their differential group delay. Using these descriptors, an analytical expression for the response of the sensor for an arbitrary input state of polarization is given and experimentally verified. It is found that the differential group delay, as well as the input and output principal states of polarization, vary when the embedded fiber is strained, leading to fluctuations in the sensor output. The use of high birefringence fibers and different embedding geometries is examined as a means for reducing the polarization dependency of the sensor
BCC vs. HCP - The Effect of Crystal Symmetry on the High Temperature Mobility of Solid He
We report results of torsional oscillator (TO) experiments on solid He at
temperatures above 1K. We have previously found that single crystals, once
disordered, show some mobility (decoupled mass) even at these rather high
temperatures. The decoupled mass fraction with single crystals is typically 20-
30%. In the present work we performed similar measurements on polycrystalline
solid samples. The decoupled mass with polycrystals is much smaller, 1%,
similar to what is observed by other groups. In particular, we compared the
properties of samples grown with the TO's rotation axis at different
orientations with respect to gravity. We found that the decoupled mass fraction
of bcc samples is independent of the angle between the rotation axis and
gravity. In contrast, hcp samples showed a significant difference in the
fraction of decoupled mass as the angle between the rotation axis and gravity
was varied between zero and 85 degrees. Dislocation dynamics in the solid
offers one possible explanation of this anisotropy.Comment: 10 pages, 5 figures, to appear in Journal of Low Temperature Physics
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Understanding Social and Cultural Contexts of Alcohol Misuse in Mexican-Origin Hispanic Men
Evidence suggests that Hispanic and non-Hispanic White men (NHW) have comparable prevalence rates of alcohol use. However, Hispanic men consistently have higher prevalence rates of alcohol misuse compared with NHW men. Consequently, Hispanic men experience disproportionate levels of adverse health consequences of alcohol misuse when compared with NHW men. The aim of this study was to explore Hispanic male perspectives and opinions regarding alcohol use patterns that may lead to disparate rates of alcohol misuse in Hispanic males. Demographic data were collected with questionnaires. Twenty semistructured one-on-one interviews were completed in English and Spanish with Mexican-origin Hispanic men (age: 44.6 +/- 11.3 years). A thematic analysis was conducted using a hybrid deductive-inductive strategy with an a priori codebook supplemented with iterative analysis of transcripts. Results suggest that alcohol misuse patterns in Hispanic males are influenced by an interaction between alcohol-related social norms and learned expressions of masculinity; a lack of knowledge of the alcohol-related health risks that further perpetuate the normalization of alcohol misuse; and expressions of masculinity and adaptive coping that lead to alcohol misuse as an escape from life stressors. Given the rapid expansion of the Hispanic population in the United States, and the disparate consequences of alcohol misuse in this population, it is imperative to consider the complex and often compounded impact of sociocultural norms and the social context on misuse-related behaviors. Viable prevention and treatment strategies should be addressed thought multicomponent, community-level strategies that more comprehensively address the complexities of alcohol misuse in this population.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
On The Mobile Behavior of Solid He at High Temperatures
We report studies of solid helium contained inside a torsional oscillator, at
temperatures between 1.07K and 1.87K. We grew single crystals inside the
oscillator using commercially pure He and He-He mixtures containing
100 ppm He. Crystals were grown at constant temperature and pressure on the
melting curve. At the end of the growth, the crystals were disordered,
following which they partially decoupled from the oscillator. The fraction of
the decoupled He mass was temperature and velocity dependent. Around 1K, the
decoupled mass fraction for crystals grown from the mixture reached a limiting
value of around 35%. In the case of crystals grown using commercially pure
He at temperatures below 1.3K, this fraction was much smaller. This
difference could possibly be associated with the roughening transition at the
solid-liquid interface.Comment: 15 pages, 6 figure
Overtaking CPU DBMSes with a GPU in whole-query analytic processing with parallelism-friendly execution plan optimization
Existing work on accelerating analytic DB query processing
with (discrete) GPUs fails to fully realize their potential for speedup through
parallelism: Published results do not achieve significant speedup over more
performant CPU-only DBMSes when processing complete queries.
This paper presents a successful
Wigner Crystalline Edges in nu < 1 Quantum Dots
We investigate the edge reconstruction phenomenon believed to occur in
quantum dots in the quantum Hall regime when the filling fraction is nu < 1.
Our approach involves the examination of large dots (< 40 electrons) using a
partial diagonalization technique in which the occupancies of the deep interior
orbitals are frozen. To interpret the results of this calculation, we evaluate
the overlap between the diagonalized ground state and a set of trial
wavefunctions which we call projected necklace (PN) states. A PN state is
simply the angular momentum projection of a maximum density droplet surrounded
by a ring of localized electrons. Our calculations reveal that PN states have
up to 99% overlap with the diagonalized ground states, and are lower in energy
than the states identified in Chamon and Wen's study of the edge
reconstruction.Comment: 8 pages, 8 figures, to be published in Phys. Rev.
Cognitive foundations of impartial punitive decision making in organizations: attribution and abstraction
Partial decision making about disciplinary responses to misbehavior is generally considered unfair and undermines the effectiveness of punishment. Nonetheless, organizational actors often struggle to remain impartial in situations that call for punishment. Impartiality appears specifically hard to obtain when some element of the transgression reflects badly upon the punisher themselves, for instance, when in the past the punisher has benefited from the misbehavior, even if just derivatively. In this paper, we argue that in such cases, punishers tend to defensively attribute causes of the transgression to the circumstances in order to protect their own selfâimage, thus leading them to relatively lenient punishments. However, we also suggest that psychological impartiality can be obtained through cognitive abstraction. An abstract understanding (highâlevel construal) of the punitive situation puts the focus squarely on the gist of the situation and makes circumstantial details less likely to be cognitively available. This hinders defensive circumstantial attribution. We show in a field study and an experiment that partiality in making decisions about punishments occurs under conditions of lowâlevel (i.e., concrete) construal, whereas impartiality is facilitated by highâlevel (i.e., abstract) construal
Tree-level FCNC in the B system: from CP asymmetries to rare decays
Tree-level Flavor-Changing Neutral Currents (FCNC) are characteristic of
models with extra vector-like quarks. These new couplings can strongly modify
the B^0 CP asymmetries without conflicting with low--energy constraints. In the
light of a low CP asymmetry in B --> J/\psi K_{S}, we discuss the implications
of these contributions. We find that even these low values can be easily
accommodated in these models. Furthermore, we show that the new data from B
factories tend to favor an O(20) enhancement of the b --> d l \bar{l}
transition over the SM expectation.Comment: 5 pages, 4 figures. Accepted version in PRD. Updated analysis with
the new results from BaBar and BELLE. Figures enlarged, small typos
corrected. Conclusions essentially unchange
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