1,411 research outputs found
GALEX Observations of CS and OH Emission in Comet 9P/Tempel 1 During Deep Impact
GALEX observations of comet 9P/Tempel 1 using the near ultraviolet (NUV)
objective grism were made before, during and after the Deep Impact event that
occurred on 2005 July 4 at 05:52:03 UT when a 370 kg NASA spacecraft was
maneuvered into the path of the comet. The NUV channel provides usable spectral
information in a bandpass covering 2000 - 3400 A with a point source spectral
resolving power of approximately 100. The primary spectral features in this
range include solar continuum scattered from cometary dust and emissions from
OH and CS molecular bands centered near 3085 and 2575 A, respectively. In
particular, we report the only cometary CS emission detected during this event.
The observations allow the evolution of these spectral features to be tracked
over the period of the encounter. In general, the NUV emissions observed from
Tempel 1 are much fainter than those that have been observed by GALEX from
other comets. However, it is possible to derive production rates for the parent
molecules of the species detected by GALEX in Tempel 1 and to determine the
number of these molecules liberated by the impact. The derived quiescent
production rates are Q(H2O) = 6.4e27 molecules/s and Q(CS2) = 6.7e24
molecules/s, while the impact produced an additional 1.6e32 H2O molecules and
1.3e29 CS2 molecules, a similar ratio as in quiescent outgassing.Comment: 15 pages, 4 figures, accepted for publication in the Astrophysical
Journa
Construct Validity of Depression and Anxiety in Pre-Adolescents and Adolescents: A Taxometric Approach.
The similarities and differences of the response classes of depression and anxiety were investigated with a sample of pre-adolescents and adolescents. The subjects were 412 pre-adolescents and adolescents from a local public school and a local psychiatric hospital. All of the participants were administered a battery of self-rating on two consecutive days. Two self-ratings of depression and two anxiety measures were utilized in order to adequately sample the content domains. Additionally, self-ratings were used to assess nine related response classes (i.e, fears, social skills, major life events, activity, hopelessness, depressed mood, anxious mood, parent-adolescent conflict, and dysfunctional thoughts). All assessment measures were evaluated in terms of their psychometric properties e.g., internal consistency, homogeneity, test-retest reliabilities, and criterion-related validity. The findings from these analyses indicated that all but one of the measures exhibited high internal consistency and homogeneity. Moreover, those measures for which test-retest reliability was assessed exhibited acceptable temporal stability. Regarding the criterion-related validity, as expected, the total scores from the depression and anxiety measures were moderately correlated. Additionally, only in a few instances did the demographic variables correlate significantly with one or more of the independent or dependent variables. Regarding the first primary analysis, the findings from the revised 2 (gender) x 2 (Trait; depression and anxiety present, depression and anxiety absent) extreme groups MANOVA indicated that the two traits could be significantly differentiated in the predicted direction, however, using this approach two Traits (anxiety present, depression present) were excluded due to zero cell sizes. The second primary analysis, cluster analysis, indicated that eight clusters could be reliably replicated across samples. These cluster(s) appear to represent each of the following response classes: depression and anxiety present, depression present, anxiety present, depression and anxiety absent. In summary, based on the findings from this study it appears that depression and anxiety can be significantly differentiated when a multivariate approach such as cluster analysis is used in an appropriate manner
The Development of a Myoelectric Training Tool for Above-Elbow Amputees
The objective of above-elbow myoelectric prostheses is to reestablish the functionality of missing limbs and increase the quality of life of amputees. By using electromyography (EMG) electrodes attached to the surface of the skin, amputees are able to control motors in myoelectric prostheses by voluntarily contracting the muscles of their residual limb. This work describes the development of an inexpensive myoelectric training tool (MTT) designed to help upper limb amputees learn how to use myoelectric technology in advance of receiving their actual myoelectric prosthesis. The training tool consists of a physical and simulated robotic arm, signal acquisition hardware, controller software, and a graphical user interface. The MTT improves over earlier training systems by allowing a targeted muscle reinnervation
(TMR) patient to control up to two degrees of freedom simultaneously. The training tool has also been designed to function as a research prototype for novel myoelectric controllers. A preliminary experiment was performed in order to evaluate the effectiveness of the MTT as a learning tool and to identify any issues with the system. Five able-bodied participants performed a motor-learning task using the EMG controlled robotic arm with the goal of moving five balls from one box to another as quickly as possible. The results indicate that the subjects improved their skill in myoelectric control over the course of the trials. A usability survey was administered to the subjects after their trials. Results from the survey showed that the shoulder degree of freedom was the most difficult to control
L^2 torsion without the determinant class condition and extended L^2 cohomology
We associate determinant lines to objects of the extended abelian category
built out of a von Neumann category with a trace. Using this we suggest
constructions of the combinatorial and the analytic L^2 torsions which, unlike
the work of the previous authors, requires no additional assumptions; in
particular we do not impose the determinant class condition. The resulting
torsions are elements of the determinant line of the extended L^2 cohomology.
Under the determinant class assumption the L^2 torsions of this paper
specialize to the invariants studied in our previous work. Applying a recent
theorem of D. Burghelea, L. Friedlander and T. Kappeler we obtain a Cheeger -
Muller type theorem stating the equality between the combinatorial and the
analytic L^2 torsions.Comment: 39 page
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111th Congress
This report explains the process for filling positions to which the President makes appointments with the advice and consent of the Senate (also referred to as PAS positions). It also identifies, for the 111th Congress, all nominations to full-time positions requiring Senate confirmation in the 15 executive departments
Screening for sexually transmitted infections at a DeAddictions service in South India
Objectives To estimate the lifetime prevalence of four sexually transmitted infections (STIs) and to identify correlates of these infections among patients seeking care for a substance use disorder at a specialized DeAddictions Unit in southern India. Methods Consecutive inpatients (n = 361; 98% male; M age = 36.7 years) admitted to DeAddictions Unit of the National Institute of Mental Health and Neuro Sciences in Bangalore, India, participated in a structured interview to obtain demographic, psychiatric, sexual behavior, and substance use data; each patient also provided a blood sample for serologic testing for HIV, chlamydia, syphilis, and hepatitis B. Results One-quarter of all patients tested positive for at least one STI. Lifetime seroprevalence rates were 12.9% for syphilis, 10.3% for chlamydia, 3.1% for hepatitis B, and 1.1% for HIV. Analyses did not reveal any consistent pattern of associations between STI status and sociodemographic, psychiatric, and sexual behavioral characteristics. Conclusions All patients should receive a comprehensive sexual assessment during standard care; for those patients who report risky sexual practices, we recommend voluntary counseling and testing for STIs. Although we do not recommend universal testing for STIs at this time, this should be revisited based upon national surveillance data
Collective efficacy and HIV Prevention in South African Townships
South African townships have high HIV prevalence and a strong need for collective action to
change normative sexual risk behaviors. This study investigated the relationship between
perceptions of individuals about collective efficacy in the community’s ability to prevent HIV and
their personal HIV risk behaviors. Men (n=1581) and women (n=718) completed anonymous
surveys within four Black African Townships in Cape Town, South Africa from June 2008 to
December 2010. Measures included demographics, alcohol use, attitudinal and behavioral norms,
sexual health communications, and sexual risk behaviors. In multivariate logistic regressions, men
were more likely to endorse collective efficacy if they were married, drank less often in alcohol
serving establishments, believed that fewer men approve of HIV risk behaviors, talk more with
others about HIV/AIDS, and had more sex partners in the past month. Women were more likely to
endorse collective efficacy if they drank alcohol less often, talked more with others about HIV/
AIDS, had more sex partners in the past month, but reported fewer unprotected sex acts in the past
month. Community level interventions that strengthen collective efficacy beliefs will have to
consider both protective and risk behaviors associated with believing that the community is ready
and capable of preventing HIV.Department of HE and Training approved lis
Heterosexual anal intercourse and HIV infection risks in the context of alcohol serving venues, Cape Town, South Africa
<p>Abstract</p> <p>Background</p> <p>The most efficient sexual behavior for HIV transmission is unprotected receptive anal intercourse. However, it is unclear what role heterosexual unprotected anal sex is playing in the world's worst HIV epidemics of southern Africa. The objective is to examine the prevalence of heterosexual unprotected anal intercourse among men and women who drink at informal alcohol serving establishments (shebeens) in South Africa.</p> <p>Methods</p> <p>Cross-sectional surveys were collected from a convenience sample of 5037 patrons of 10 shebeens in a peri-urban township of Cape Town, South Africa. Analyses concentrated on establishing the rates of unprotected anal intercourse practiced by men and women as well as the factors associated with practicing anal intercourse.</p> <p>Results</p> <p>We found that 15% of men and 11% of women reported anal intercourse in the previous month, with 8% of men and 7% of women practicing any unprotected anal intercourse. Multiple logistic regression showed that younger age, having primary and casual sex partners, and meeting sex partners at shebeens were independently associated with engaging in anal intercourse. Mathematical modeling showed that individual risks are significantly impacted by anal intercourse but probably not to the degree needed to drive a generalized HIV epidemic.</p> <p>Conclusions</p> <p>Anal intercourse likely plays a significant role in HIV infections among a small minority of South Africans who patronize alcohol serving establishments. Heterosexual anal intercourse, the most risky sexual behavior for HIV transmission, should not be ignored in HIV prevention for South African heterosexuals. However, this relatively infrequent behavior should not become the focus of prevention efforts.</p
Gender and Depression Moderate Response to Brief Motivational Intervention for Alcohol Misuse Among College Students
Objective: Brief motivational interventions (BMIs) effectively reduce problematic drinking in college students. However, not all students benefit, and little is known about the subgroups of students for whom BMIs are most effective. In the present study, we examined 2 factors that may influence BMI efficacy: gender and depression. Method: We reanalyzed data from a clinical trial in which heavy drinking students (N Ď 330; 65% female) were randomized to a BMI (n Ď 165) or an assessment only control (n Ď 165). Depression was assessed at baseline; past-month typical drinks per week, heavy drinking frequency, and consequences were assessed at baseline and 1 month. Three-and 2-way interactions among intervention condition (BMI vs. control), gender (male vs. female), and depression (low vs. high) were tested. Results: We observed 3-way interaction effects on 2 outcomes: (a) typical drinks per week and (b) frequency of heavy drinking at 1 month. Relative to controls and adjusting for baseline drinking, low-depression women reduced their drinking more after a BMI whereas high-depression women did not show differential improvement. In contrast, high-depression men showed significant reductions in weekly drinks following the BMI whereas low-depression men did not show differential improvement. In addition, higher levels of depression were associated with higher levels of consequences at follow-up across conditions. Conclusions: BMIs are indicated for heavy drinking, depressed men, consistent with recommendations for implementing screening and brief intervention in mental health settings. However, BMIs may need to be refined to enhance their efficacy for depressed women
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