3,523 research outputs found
Evaluation of wear resistance of fourteen gear materials Final technical report, Jun. 1965 - Mar. 1970
Vacuum and atmospheric tests of selected gear materials for wear resistanc
GaAs monolithic frequency doublers with series connected varactor diodes
GaAs monolithic frequency doublers using series connected varactor diodes have been fabricated for the first time. Output powers of 150 mW at 36.9 GHz with 24% efficiency and 300 mW at 24.8 GHz with 18% efficiency have been obtained. Peak efficiencies of 35% at output power levels near 100 mW have been achieved at both frequencies. Both K-band and Ka-band frequency doublers are derived from a lower power, single-diode design by series connection of two diodes and scaling to achieve different power and frequency specifications. Their fabrication was accomplished using the same process sequence
Estimating the Population Attributable Fraction of Asthma Due to Electronic Cigarette Use and Other Risk Factors Using Kentucky Behavioral Risk Factor Survey Data, 2016-2017
Introduction: Electronic nicotine delivery systems ENDS have become popular in the United States among both new users of nicotine and those seeking less harmful alternatives to traditional cigarettes. Users often perceive ENDS as being less harmful than traditional cigarettes. This study investigated the relationship between use of ENDS and asthma in a representative sample of adults. Methods: For this cross-sectional study, we used data from the Kentucky Behavioral Risk Factor Surveillance System telephone survey data from 2016-2017. Using a weighted multivariable logistic regression analysis, we identified important covariates to adjust for to calculate the population attributable fraction (PAF) of asthma due to ENDS and other modifiable risk factors factors (cigarette use, obesity, education, and employment). The confidence intervals for the PAFs were estimated using bootstrap methods of variance estimation. Results: We found that 10.6% of those aged 18-30 reported currently had asthma. After adjusting for noted covariates, ENDS use did not significantly increase the odds of asthma. In the final PAF model, the PAF of asthma due to ENDS was 0.4% (95% CI: -5.41, 6.21). Conclusion: While these findings suggest only modest effects of ENDS use on asthma prevalence, future research including older age groups and more long-term users might produce different results
A New Species of Blepharicera Macquart (Diptera: Blephariceridae) from Western North America
During a review of the Blepharicera of western North America, we discovered a new species from several mid-sized rivers in southwestern Oregon and northwestern California. We hereby present descriptions of the larvae, pupae, and adults of B. kalmiopsis, new species. Diagnostic characters and a brief discussion of bionomics and distribution are also provided. Based on previous and ongoing studies, B. kalmiopsis clearly belongs to the B. micheneri Alexander species group and appears closely related to B. zionensis Alexander
Interactive manipulation of microparticles in an octagonal sonotweezer
An ultrasonic device for micro-patterning and precision manipulation of micrometre-scale particles is demonstrated. The device is formed using eight piezoelectric transducers shaped into an octagonal cavity. By exciting combinations of transducers simultaneously, with a controlled phase delay between them, different acoustic landscapes can be created, patterning micro-particles into lines, squares, and more complex shapes. When operated with all eight transducers the device can, with appropriate phase control, manipulate the two dimensional acoustic pressure gradient; it thus has the ability to position and translate a single tweezing zone to different locations on a surface in a precise and programmable manner
Influence of Source Credibility on Agricultural Water Use Communication
As the agriculture industry strives to communicate with the public about its role in protecting natural resources such as water, it struggles to provide messages from sources the public trusts. The purpose of this quasi-experimental study explored public perception of agricultural water use and how perception was influenced by a video message delivered from four different sources including 1) an environmental scientist from the Nature Conservancy, 2) a farmer, 3) a regulator from a Florida water management district, and 4) a water scientist from the University of Florida. The findings revealed that overall the general public had a positive view of how the agriculture industry used water, regardless of message source. Differences between groups were evident when message source expertise and trustworthiness was dependent on domain area. Results indicated the respondents receiving the Nature Conservancy video treatment exhibited a significantly higher level of agreement with negatively framed items related to agriculture’s relationship with the natural environment than the respondents receiving the farmer video treatment. Based on the findings from this study, agricultural communicators should consider the trustworthiness and perceived expertise of sources, such as representatives from regulatory agencies, educational institutions, members of the agriculture sector, or environmental organizations, when developing messages about water use targeted at the general public
Using Multiple-hierarchy Stratification and Life Course Approaches to Understand Health Inequalities: The Intersecting Consequences of Race, Gender, SES, and Age
This study examines how the intersecting consequences of race-ethnicity, gender, socioeconomics status (SES), and age influence health inequality. We draw on multiple-hierarchy stratification and life course perspectives to address two main research questions. First, does racial-ethnic stratification of health vary by gender and/or SES? More specifically, are the joint health consequences of racial-ethnic, gender, and socioeconomic stratification additive or multiplicative? Second, does this combined inequality in health decrease, remain stable, or increase between middle and late life? We use panel data from the Health and Retirement Study (N = 12,976) to investigate between- and within-group differences in in self-rated health among whites, blacks, and Mexican Americans. Findings indicate that the effects of racial-ethnic, gender, and SES stratification are interactive, resulting in the greatest racial-ethnic inequalities in health among women and those with higher levels of SES. Furthermore, racial-ethnic/gender/SES inequalities in health tend to decline with age. These results are broadly consistent with intersectionality and aging-as-leveler hypotheses
Planet Candidates from K2 Campaigns 5-8 and Follow-Up Optical Spectroscopy
We present 151 planet candidates orbiting 141 stars from K2 campaigns 5-8
(C5-C8), identified through a systematic search of K2 photometry. In addition,
we identify 16 targets as likely eclipsing binaries, based on their light curve
morphology. We obtained follow-up optical spectra of 105/141 candidate host
stars and 8/16 eclipsing binaries to improve stellar properties and to identify
spectroscopic binaries. Importantly, spectroscopy enables measurements of host
star radii with 10% precision, compared to 40% precision when
only broadband photometry is available. The improved stellar radii enable
improved planet radii. Our curated catalog of planet candidates provides a
starting point for future efforts to confirm and characterize K2 discoveries.Comment: Accepted for publication in the Astronomical Journal; 17 pages, 8
figures, 2 tables, download source for full table
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