7,087 research outputs found
Single contact tailored gain phased array of semiconductor lasers
We demonstrate a single contact tailored gain-guided array in which the gain profile across the array is made strongly asymmetric by varying the width of the contact stripes. A proton isolated array of six (GaAl)As lasers with 5-µm separations and widths varying linearly between 3 and 8 µm had a single lobed far field 2° wide, close to the diffraction limit for a single supermode. Fabrication of this device is simple, and suited to large-scale processing techniques. We also show that in such an asymmetric gain-guided array the fundamental mode is favored over higher order modes, and that higher order modes can have single lobed far-field patterns differing only slightly from that of the fundamental
Structural and Dynamical Anomalies of a Gaussian Core Fluid: a Mode Coupling Theory Study
We present a theoretical study of transport properties of a liquid comprised
of particles uist1:/home/sokrates/egorov/oldhome/Pap41/Submit > m abs.tex We
present a theoretical study of transport properties of a liquid comprised of
particles interacting via Gaussian Core pair potential. Shear viscosity and
self-diffusion coefficient are computed on the basis of the mode-coupling
theory, with required structural input obtained from integral equation theory.
Both self-diffusion coefficient and viscosity display anomalous density
dependence, with diffusivity increasing and viscosity decreasing with density
within a particular density range along several isotherms below a certain
temperature. Our theoretical results for both transport coefficients are in
good agreement with the simulation data
Four Decades of the Journal \u3ci\u3eLaw and Human Behavior\u3c/i\u3e: A Content Analysis
Although still relatively young, the journal Law and Human Behavior (LHB) has amassed a publication history of more than 1300 full-length articles over four decades. Yet, no systematic analysis of the journal has been done until now. The current research coded all full-length articles to examine trends over time, predictors of the number of Google Scholar citations, and predictors of whether an article was cited by a court case. The predictors of interest included article organization, research topics, areas of law, areas of psychology, first-author gender, first-author country of institutional affiliation, and samples employed. Results revealed a vast and varied field that has shown marked diversification over the years. First authors have consistently become more diversified in both gender and country of institutional affiliation. Overall, the most common research topics were jury/judicial decision-making and eyewitness/memory, the most common legal connections were to criminal law and mental health law, and the most common psychology connection was to social-cognitive psychology. Research in psychology and law has the potential to impact both academic researchers and the legal system. Articles published in LHB appear to accomplish both
Helioseismic analysis of the solar flare-induced sunquake of 2005 January 15
We report the discovery of one of the most powerful sunquakes detected to
date, produced by an X1.2-class solar flare in active region 10720 on 2005
January 15. We used helioseismic holography to image the source of seismic
waves emitted into the solar interior from the site of the flare. Acoustic
egression power maps at 3 and 6 mHz with a 2 mHz bandpass reveal a compact
acoustic source strongly correlated with impulsive hard X-ray and
visible-continuum emission along the penumbral neutral line separating the two
major opposing umbrae in the -configuration sunspot that predominates
AR10720. The acoustic emission signatures were directly aligned with both hard
X-ray and visible continuum emission that emanated during the flare. The
visible continuum emission is estimated at J,
approximately 500 times the seismic emission of J. The
flare of 2005 January 15 exhibits the same close spatial alignment between the
sources of the seismic emission and impulsive visible continuum emission as
previous flares, reinforcing the hypothesis that the acoustic emission may be
driven by heating of the low photosphere. However, it is a major exception in
that there was no signature to indicate the inclusion of protons in the
particle beams thought to supply the energy radiated by the flare. The
continued strong coincidence between the sources of seismic emission and
impulsive visible continuum emission in the case of a proton-deficient
white-light flare lends substantial support to the ``back -- warming''
hypothesis, that the low photosphere is significantly heated by intense Balmer
and Paschen continuum-edge radiation from the overlying chromosphere in
white-light flares.Comment: 12 pages, 7 figures, published in MNRA
Today\u27s Predatory Lending Tactics Require New Strategies - and New Laws: How a Case from Chicago Helped Change Illinois Law
Diffusion Enhancement in a Periodic Potential under High-Frequency Space-Dependent Forcing
We study the long-time behavior of underdamped Brownian particle moving
through a viscous medium and in a systematic potential, when it is subjected to
a space-dependent high-frequency periodic force. When the frequency is very
large, much larger than all other relevant system-frequencies, there is a
Kapitsa time-window wherein the effect of frequency dependent forcing can be
replaced by a static effective potential. Our new analysis includes the case
when the forcing, in addition to being frequency-dependent, is space-dependent
as well. The results of the Kapitsa analysis then lead to additional
contributions to the effective potential. These are applied to the numerical
calculation of the diffusion coefficient (D) for a Brownian particle moving in
a periodic potential. Presented are numerical results, which are in excellent
agreement with theoretical predictions and which indicate a significant
enhancement of D due to the space-dependent forcing terms. In addition we study
the transport property (current) of underdamped Brownian particles in a ratchet
potential.Comment: RevTex 6 pages, 5 figure
Exposure of female juvenile rainbow trout to alkylphenolic compounds results in modifications to growth and ovosomatic index
The alkylphenol ethoxylates (APEOs) are a major group of non-ionic surfactants. Biodegradation of these compounds is incomplete during sewage treatment, thus they are ubiquitous aquatic pollutants. All the main degradation products of APEOs have recently been demonstrated to have estrogenic properties in vitro, but their effects in vivo remain to be established. In this study, female juvenile rainbow trout (Oncorhynchus mykiss Walbaum) were exposed to octylphenol (OP), nonylphenol (NP), nonylphenol diethoxylate (NP2EO) and nonylphenol mono-carboxylic acid (NP1EC) at environmentally relevant concentrations (Experiment 1: 1, 10 and 50 ug/L; Experiment 2: 1, 10 and 30 ug/L). Exposure to APEO’s commenced at hatch (day 0) and was terminated on day 22 (Expt. 1) or day 35 (Expt. 2). Body weight and fork length of representative samples of fish from each treatment group were recorded at intervals up to 108 days (Expt. 1) or 466 days (Expt. 2). In Experiment 1, significant differences in size of the exposed fish, related to treatment, were still apparent on day 108, 86 days after withdrawal of the treatments. These observations were confirmed during Experiment 2, in which significant changes in body weight and fork length as a consequence of exposure to the compounds were observed approximately 15 days after exposure was terminated. These differences were sustained for at least 466 days in the case of NP and NP1EC. In addition, the ovosomatic index (OSI) of fish exposed to NP and NP1EC was significantly affected by the treatment. Survival of fish in the natural environment is strongly influenced by body size, and an appropriate OSI is a crucial factor in successful reproduction. Therefore, exposure of natural populations of fish to these chemicals at concentrations currently measurable in the aquatic environment may have an impact on the performance of those populations
EXPOSURE OF FEMALE JUVENILE RAINBOW TROUT TO ALKYLPHENOLIC COMPOUNDS RESULTS IN MODIFICATIONS TO GROWTH AND OVOSOMATIC INDEX
Measurement of mutual inductance from frequency dependence of impedance of AC coupled circuit using digital dual-phase lock-in amplifier
We present a simple method to determine the mutual inductance between two
coils in a coupled AC circuit by using a digital dual-phase lock-in amplifier.
The frequency dependence of the real and imaginary parts is measured as the
coupling constant is changed. The mutual inductance decreases as the
distance between the centers of coils is increased. We show that the
coupling constant is proportional to with an exponent (
3). This coupling is similar to that of two magnetic moments coupled through a
dipole-dipole interaction.Comment: 9 pages, 10 figures, Fig.1 is corrected, figures in png files, short
version is published in Am. J. Phys. 76, (2008) 12
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