2,765 research outputs found
Active cleaning technique for removing contamination from optical surfaces in space
Plasma cleaning experiments were completed on hydrocarbon contaminant films, experiments were initiated to determine a satisfactory technique for depositing contaminant films, and an experiment was conducted to determine whether specimens are being thermally cleaned rather than plasma cleaned. Results of plasma cleaning experiments on hydrocarbon contaminant films showed that the optical properties of mirrors and gratings could be satisfactorily restored. Results on fused silica optical flats were inconclusive because of the insensitivity of measurement techniques to the contaminant films. White thermal control surfaces, degraded by the hydrocarbon contaminant film, could not be restored by oxygen plasma exposure. The reflectance of silvered FEP Teflon thermal control surfaces could be restored by plasma cleaning. Experiments with a silicone contaminant indicated that it could not be easily polymerized onto surfaces with ultraviolet radiation. Results of the thermal cleaning experiment showed that the polymerized hydrocarbon contaminant film could not be removed by heating in vacuum to a temperature in excess of that expected during plasma cleaning
Phase Lags in the Optical-Infrared Light Curves of AGB Stars
To search for phase lags in the optical-infrared light curves of asymptotic
giant branch stars, we have compared infrared data from the COBE DIRBE
satellite with optical light curves from the AAVSO and other sources. We found
17 examples of phase lags in the time of maximum in the infrared vs. that in
the optical, and 4 stars with no observed lags. There is a clear difference
between the Mira variables and the semi-regulars in the sample, with the
maximum in the optical preceding that in the near-infrared in the Miras, while
in most of the semi-regulars no lags are observed. Comparison to published
theoretical models indicates that the phase lags in the Miras are due to strong
titanium oxide absorption in the visual at stellar maximum, and suggests that
Miras pulsate in the fundamental mode, while at least some semi-regulars are
first overtone pulsators. There is a clear optical-near-infrared phase lag in
the carbon-rich Mira V CrB; this is likely due to C2 and CN absorption
variations in the optical.Comment: AJ, in pres
NGC 4314. III. Inflowing Molecular Gas Feeding a Nuclear Ring of Star Formation
NGC 4314 is an early-type barred galaxy containing a nuclear ring of recent
star formation. We present CO(1-0) interferometer data of the bar and
circumnuclear region with 2.3 x 2.2 arcsec spatial resolution and 13 km/s
velocity resolution acquired at the Owens Valley Radio Observatory . These data
reveal a clumpy circumnuclear ring of molecular gas. We also find a peak of CO
inside the ring within 2 arcsec of the optical center that is not associated
with massive star formation. We construct a rotation curve from these CO
kinematic data and the mass model of Combes et al. (1992). Using this rotation
curve, we have identified the location of orbital resonances in the galaxy.
Assuming that the bar ends at corotation, the circumnuclear ring of star
formation lies between two Inner Lindblad Resonances, while the nuclear stellar
bar ends near the IILR. Deviations from circular motion are detected just
beyond the CO and H-alpha ring, where the dust lanes along the leading edge of
the bar intersect the nuclear ring. These non-circular motions along the minor
axis correspond to radially inward streaming motions at speeds of 20 - 90 km/s
and clearly show inflowing gas feeding an ILR ring. There are bright HII
regions near the ends of this inflow region, perhaps indicating triggering of
star formation by the inflow.Comment: 25 pages, uses aasms.sty. 7 Postscript figures, 12 JPEG figures.
Figures may be retrieved from
ftp://clyde.as.utexas.edu/pub/N4314COfigs.tar.g
Communication Apprehension and Interpersonal Skills in Physical Therapy Students : A Comparative Study of Problem-Based Learning and Traditional Curricula
Physical Therapy education has been challenged to prepare students to meet the increasing demands upon and changing needs of physical therapy practice in the evolving health delivery system. Today\u27s practitioner needs strong interpersonal and collaborative skills for effective communication with patients, families, third party payers, community and other members of the health care team. The characteristics of problem-based learning (PBL) curricula appeared to offer greater potential for students to develop communication skills as compared to traditional curricula. Therefore, this study used available measures of communication apprehension and clinical performance of communication related behaviors to compare students educated in PBL curricula with students from traditional educational models
Head-up displays : effect of information location on the processing of superimposed symbology
Exploring the Use of the Check & Connect Program as a Behavioral Intervention for Students with Attention-Deficit Hyperactivity Disorder
Student engagement is critical to the overall academic and behavioral well-being of a child in school. When working with students who have been diagnosed with Attention-Deficit Hyperactivity Disorder (ADHD), it is important for students to understand that, even though it may be more difficult for them to complete certain tasks or follow certain rules, they can be engaged and successful. Check & Connect is a research-based intervention which involves developing a strong, positive relationship between a student and a trained mentor (University of Minnesota, 2013). A single subject design using a non-concurrent multiple baseline across students’ was employed to determine the effect of a Check & Connect program on appropriate classroom behaviors for four 2nd grade students who had a medical diagnosis of ADHD. The behaviors that were addressed included remaining on-task, following directions and completing assignments throughout the school day. Each student had the opportunity to complete a daily checklist and earn up to eight or ten points per day for assignment completion and on-task behavior depending on the schedule of the classroom. Based on the results of this study, the implementation of the “Check & Connect” program yielded positive results for three of the four students who participated
A Review of the Legal Issues Surrounding Academic Dismissal
Among the challenges faced by physical therapy educators is to determine whether students have made sufficient progress in the academic and/or clinical curriculum to merit continuance in the physical therapy program. At times, faculties must make the decision to dismiss a student due to failure to achieve the necessary performance criteria. These decisions are often clouded by fear of lawsuits and confusion about the responsibilities and prerogatives of professional judgments. This article traces the history of case law related to academic dismissal, examining a number of significant cases and the ramifications of these cases for professional programs. Key legal concepts are defined and discussed. Recommendations are provided for preserving the rights of the student to due process while protecting academic institutions
The multidimensionality of health protective behaviors
This study explored the relationship among health protective behaviors in an asymptomatic population and identified multiple dimensions. A battery containing measures of health locus of control, general well-being and health value was given to 395 college students. The findings suggested that the three sets of variables offered predictive models unique to each health behavior dimension. Perceived outcomes or benefits were also assessed in relation to the specific health behaviors endorsed by each individual and were found to differentially relate to the various dimensions, providing suggestive evidence for underlying motivations. Several implications were discussed. First, multiple models are needed given multiple dimensions of health behavior. Second, health behaviors are not always performed for health related reasons, and alternative motivations need to be considered. Once identified, these motivations will allow better refinement of health enhancement models based on an approach theory, rather than one of disease-avoiDance
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