438 research outputs found
Feasibility of a chemical poison loop system
Chemical poison loop system for reactivity control of tungsten water moderated rocket reacto
Waveguiding microstructures in Nd:YAG with cladding and inner dual-line configuration produced by femtosecond laser inscription
We demonstrate a new design of waveguiding microstructure, which contains both cladding and inner dual-line configurations, in Nd:YAG laser crystals inscribed by femtosecond laser processing. Based on this prototype, a few “cladding + dual-line” hybrid structures with different parameters have been successfully manufactured in Nd:YAG. The waveguide lasing at 1.06 μm has been realized in the hybrid structures under 808-nm optical pump. Compared to the single dual-line waveguides, the dual-line core in hybrid configuration benefits from the large-area pump from the external cladding, reaching an enhancement of 26% on the maximum output power and of 24% on the slope efficiency of the waveguide lasing. In addition, the symmetric stress field of external cladding structure produces anisotropic stress field in the inner cores, supporting guidance along both TE and TM polarizations, thus differing significantly from the single dual-line waveguides.The work is supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (No.20130131130001) and Junta de Castilla y León under Project SA086A12-2. Support from the Centro de Láseres Pulsados (CLPU) is also acknowledged
Avaliação, caracterização e manipulação de plantas medicinais do horto da Embrapa Amazônia Oriental.
Obesity Prevalence, Weight-Related Beliefs and Behaviors among Low-Income Ethnically Diverse National Job Corps Students
The obesity rates of Job Corps students, a predominantly ethnic minority and low income group of youth, are unknown. The purpose of this project was to examine obesity rates among these youth as well as their weight-related perceptions and behavior. First, medical charts (N=641) of all Job Corps students (ages 16-25) who were enrolled in the program in the past year were examined for height and weight. In the second phase of the study, 344 Job Corp students were recruited and information on weight perceptions, knowledge of obesity consequences, and weight loss behavior were examined. Almost half of the participants were overweight or obese. Overweight males were less likely to perceive themselves as being overweight than females. The majority of participants were aware of obesity-related health consequences but of those with past weight loss attempts, only 13% reported using both exercise and diet. High levels of overweight and obesity among Job Corps students are likely to impact employment and career goals. Evidence-based obesity interventions for Job Corps students are needed
Continuous-wave lasing at 1.06μm in femtosecond laser written Nd:KGW waveguides
We report on the buried channel waveguide laser at 1065 nm in Nd:KGW waveguides fabricated by femtosecond laser writing with dual-line approach. A relatively high scanning speed of 0.5 mm/s enables acceptable propagation loss less than 2 dB/cm. The fluorescence emission spectra of Nd3+ ions measured shows that the fluorescence properties were well preserved in the waveguide region. A stable continuous wave laser at 1065 nm has been obtained at room temperature in the buried channel waveguides by optical pumping at 808 nm. A maximum output power of 33 mW and a slope efficiency of 52.3% were achieved in the Nd:KGW waveguide laser system.The work is supported by the National Natural Science Foundation of China (No. 11274203), the Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 20130131130001) and Junta de Castilla y León under project SA086A12-2. Support from the Centro de Láseres Pulsados (CLPU) is also acknowledged
Coleta, avaliação e caracterização de plantas medicinais do horto da Embrapa Amazônia Oriental.
Psychometric Development of the Research and Knowledge Scale
BACKGROUND: Many research participants are misinformed about research terms, procedures, and goals; however, no validated instruments exist to assess individual\u27s comprehension of health-related research information. We propose research literacy as a concept that incorporates understanding about the purpose and nature of research.
OBJECTIVES: We developed the Research and Knowledge Scale (RaKS) to measure research literacy in a culturally, literacy-sensitive manner. We describe its development and psychometric properties.
RESEARCH DESIGN: Qualitative methods were used to assess perspectives of research participants and researchers. Literature and informed consent reviews were conducted to develop initial items. These data were used to develop initial domains and items of the RaKS, and expert panel reviews and cognitive pretesting were done to refine the scale. We conducted psychometric analyses to evaluate the scale.
SUBJECTS: The cross-sectional survey was administered to a purposive community-based sample (n=430) using a Web-based data collection system and paper.
MEASURES: We did classic theory testing on individual items and assessed test-retest reliability and Kuder-Richardson-20 for internal consistency. We conducted exploratory factor analysis and analysis of variance to assess differences in mean research literacy scores in sociodemographic subgroups. RESULTS: The RaKS is comprised of 16 items, with a Kuder-Richardson-20 estimate of 0.81 and test-retest reliability 0.84. There were differences in mean scale scores by race/ethnicity, age, education, income, and health literacy (all P \u3c 0.01).
CONCLUSIONS: This study provides preliminary evidence for the reliability and validity of the RaKS. This scale can be used to measure research participants\u27 understanding about health-related research processes and identify areas to improve informed decision-making about research participation
Monolithic crystalline cladding microstructures for efficient light guiding and beam manipulation in passive and active regimes
Miniature laser sources with on-demand beam features are desirable devices for a broad range of photonic
applications. Lasing based on direct-pump of miniaturized waveguiding active structures offers a low-cost
but intriguing solution for compact light-emitting devices. In this work, we demonstrate a novel family of
three dimensional (3D) photonic microstructures monolithically integrated in a Nd:YAG laser crystal wafer.
They are produced by the femtosecond laser writing, capable of simultaneous light waveguiding and beam
manipulation. In these guiding systems, tailoring of laser modes by both passive/active beam splitting and
ring-shaped transformation are achieved by an appropriate design of refractive index patterns. Integration
of graphene thin-layer as saturable absorber in the 3D laser structures allows for efficient passive
Q-switching of tailored laser radiations which may enable miniature waveguiding lasers for broader
applications. Our results pave a way to construct complex integrated passive and active laser circuits in
dielectric crystals by using femtosecond laser written monolithic photonic chipsThis work was supported by National Natural Science Foundation of China (No.
11274203), Specialized Research Fund for the Doctoral Program of Higher Education of
China (No. 20130131130001), and Junta de Castillay León under project SA086A12-
Differences Between Women and Men Undergoing TKR and THR in a National Research Consortium
Introduction: Prior studies reported higher prevalence of arthritis, greater disability, lower rate of utilization of total knee replacement (TKR) and total hip replacement (THR) in women as compared to men, as well as differences in outcomes after surgery. We examined sex differences in terms of demographic and clinical factors that influence surgical outcomes in a national sample of patients who underwent TKR or THR.
Methods: Patients undergoing primary THR and TKR from 7/1/11 through 12/03/12 were identified from a national research consortium that gathers demographic data, the Western Ontario and McMaster Universities Arthritis Index (WOMAC) estimated from the Knee injury and Osteoarthritis Outcome Score (KOOS) or the Hip injury and Osteoarthritis Outcome Score (HOOS), Short Form 36 Physical Component Score (PCS) and Mental Component Score (MCS) and musculoskeletal burden of illness. Descriptive statistics were performed.
Results: Primary TKR patients included 2042 women and 1276 men. Women were more likely nonwhite (11.2% vs. 7.5%), unmarried (40.3% vs. 17.8%), lower income (p
Conclusion: In this national sample, women undergoing primary THR and TKR have more severe arthritis, greater functional impairment and greater burden of musculoskeletal disease as compared to men. Understanding these differences will help tailor peri-operative care to the needs of the patients
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