53,100 research outputs found
Are there gender differences in perceived sexual self-efficacy among African-American adolescents?
Background: African American adolescents accounted for more than half of all HIV/AIDS cases in 2009. Behavioral Strategies are needed to help lessen the incidence of HIV/AIDS among this population.
Purpose: The aim of his study was to examine sexual self-efficacy practices and beliefs among African American adolescents. We also examined gender differences between African American adolescents to better understand their perceptions of sexual self-efficacy, condom use intention, and other safer sex practices and beliefs.
Methods: A cross-sectional study was conducted with 214 African American adolescents using survey instruments to examine their beliefs, perception and intentions on the use of condoms, sexual self-efficacy and safe sex practices. Participants were recruited though a mass media campaign and local youth serving organizations within Sedgwick County, KS.
Results: Our findings indicate significant differences exist between genders in perception of sexual self-efficacy among African American adolescents. Females were found to have higher perceived sexual self-efficacy compared to males. Having high negotiation skills and a sexual partner who approved of condom use were significant predictors for high perceived sexual self-efficacy.
Conclusions: African American adolescent females were more likely to have higher perceived sexual self-efficacy then African American male adolescents. Because of the dynamics that exist in male and female relationships and the mediating role sexual self-efficacy might play in engaging in safe sex practices, it is important to design gender specific interventions in order to curb the spread of HIV/AIDS and other STDS/STIās
USSR Space Life Sciences Digest
Research in exobiology, life sciences technology, space biology, and space medicine and physiology, primarily using data gathered on the Salyut 6 orbital space station, is reported. Methods for predicting, diagnosing, and preventing the effects of weightlessness are discussed. Psychological factors are discussed. The effects of space flight on plants and animals are reported. Bioinstrumentation advances are noted
Intensity-Correlation Spectroscopy
A survey is given of techniques for spectroscopic analysis using intensity fluctuations. Particular attention is given to counting times, the role of macroscopic sources and detectors, and the electronic constraints placed on the observations
Microwave resonance of the reentrant insulating quantum Hall phases in the 1st excited Landau Level
We present measurements of the real diagonal microwave conductivity of the
reentrant insulating quantum Hall phases in the first excited Landau level at
temperatures below 50 mK. A resonance is detected around filling factor
and weaker frequency dependence is seen at and 2.28.
These measurements are consistent with the formation of a bubble phase crystal
centered around these at very low temperatures
Oscillator strengths and line widths of dipole-allowed transitions in Ā¹ā“Nā between 89.7 and 93.5ānm
Line oscillator strengths in the 20 electric dipole-allowed bands of Ā¹ā“Nā in the 89.7ā93.5nm (111480ā106950cmā»Ā¹) region are reported from photoabsorptionmeasurements at an instrumental resolution of ā¼6mĆ
(0.7cmā»Ā¹) full width at half maximum. The absorptionspectrum comprises transitions to vibrational levels of the 3pĻįµ¤cā²āĀ¹Ī£įµ¤āŗ, 3pĻįµ¤cĀ³Ī įµ¤, and 3sĻgoāĀ¹Ī įµ¤Rydberg states and of the bā²Ā¹Ī£įµ¤āŗ and bĀ¹Ī įµ¤ valence states. The J dependences of band f values derived from the experimental line f values are reported as polynomials in Jā²(Jā²+1) and are extrapolated to Jā²=0 in order to facilitate comparisons with results of coupled Schrƶdinger-equation calculations. Most bands in this study are characterized by a strong J dependence of the band f values and display anomalous P-, Q-, and R-branch intensity patterns. Predissociation line widths, which are reported for 11 bands, also exhibit strong J dependences. The f value and line width patterns can inform current efforts to develop comprehensive spectroscopic models that incorporate rotational effects and predissociation mechanisms, and they are critical for the construction of realistic atmospheric radiative-transfer models.This work was supported in part by NASA Grant No.
NNG05GA03G to Wellesley College and Australian Research
Council Discovery Program Grant No. DP0558962
CMB lensing and primordial squeezed non-Gaussianity
Squeezed primordial non-Gaussianity can strongly constrain early-universe
physics, but it can only be observed on the CMB after it has been
gravitationally lensed. We give a new simple non-perturbative prescription for
accurately calculating the effect of lensing on any squeezed primordial
bispectrum shape, and test it with simulations. We give the generalization to
polarization bispectra, and discuss the effect of lensing on the trispectrum.
We explain why neglecting the lensing smoothing effect does not significantly
bias estimators of local primordial non-Gaussianity, even though the change in
shape can be >~10%. We also show how tau_NL trispectrum estimators can be well
approximated by much simpler CMB temperature modulation estimators, and hence
that there is potentially a ~10-30% bias due to very large-scale lensing modes,
depending on the range of modulation scales included. Including dipole sky
modulations can halve the tau_NL error bar if kinematic effects can be
subtracted using known properties of the CMB temperature dipole. Lensing
effects on the g_NL trispectrum are small compared to the error bar. In
appendices we give the general result for lensing of any primordial bispectrum,
and show how any full-sky squeezed bispectrum can be decomposed into orthogonal
modes of distinct angular dependence.Comment: 22 pages, 6 figures; minor edits to match published versio
Voice control of the space shuttle video system
A pilot voice control system developed at the Jet Propulsion Laboratory (JPL) to test and evaluate the feasibility of controlling the shuttle TV cameras and monitors by voice commands utilizes a commercially available discrete word speech recognizer which can be trained to the individual utterances of each operator. Successful ground tests were conducted using a simulated full-scale space shuttle manipulator. The test configuration involved the berthing, maneuvering and deploying a simulated science payload in the shuttle bay. The handling task typically required 15 to 20 minutes and 60 to 80 commands to 4 TV cameras and 2 TV monitors. The best test runs show 96 to 100 percent voice recognition accuracy
A retrospective study of the short-term complication rate following 750 elective elbow arthroscopies
Quasar Microlensing at High Magnification and the Role of Dark Matter: Enhanced Fluctuations and Suppressed Saddlepoints
Contrary to naive expectation, diluting the stellar component of the lensing
galaxy in a highly magnified system with smoothly distributed ``dark'' matter
increases rather than decreases the microlensing fluctuations caused by the
remaining stars. For a bright pair of images straddling a critical curve, the
saddlepoint (of the arrival time surface) is much more strongly affected than
the associated minimum. With a mass ratio of smooth matter to microlensing
matter of 4:1, a saddlepoint with a macro-magnification of mu = 9.5 will spend
half of its time more than a magnitude fainter than predicted. The anomalous
flux ratio observed for the close pair of images in MG0414+0534 is a factor of
five more likely than computed by Witt, Mao and Schechter if the smooth matter
fraction is as high as 93%. The magnification probability histograms for
macro-images exhibit distinctly different structure that varies with the smooth
matter content, providing a handle on the smooth matter fraction. Enhanced
fluctuations can manifest themselves either in the temporal variations of a
lightcurve or as flux ratio anomalies in a single epoch snapshot of a multiply
imaged system. While the millilensing simulations of Metcalf and Madau also
give larger anomalies for saddlepoints than for minima, the effect appears to
be less dramatic for extended subhalos than for point masses. Morever,
microlensing is distinguishable from millilensing because it will produce
noticeable changes in the magnification on a time scale of a decade or less.Comment: As accepted for publication in ApJ. 17 pages. Substantial revisions
include a discussion of constant M/L models and the calculation of a
"photometric" dark matter fraction for MG0414+053
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