299 research outputs found
Flight measured downwash of the QSRA
Several reports have been written on the performance of the Quiet Short-Haul Research Aircraft, which shows the advantages of upper-surface blowing or the propulsive-lift wing as it applies to lift, maneuverability, and short takeoff and landing. This high lift generation at low speeds results in substantial downwash, especially in the low-aft fuselage tail position. The high T-tail of the Quiet Short-Haul Research Aircraft minimizes the undesirable downwash effects from the propulsive-lift wing. Queries from Department of Defense agencies and industry for quantitative values prompted a series of flight-measured downwash tests at the high T-tail and the low aft fuselage position. The results are presented in a summarized format, showing downwash, Delta epsilon/Delta a, for both locations. As would be expected, downwash increases for increased power and USB flap settings. The downwash is greater in the low aft-fuselage position as compared to the high T-tail area
A potential flight evaluation of an upper-surface-blowing/circulation-control-wing concept
The technology data base for powered lift aircraft design has advanced over the last 15 years. NASA's Quiet Short Haul Research Aircraft (QSRA) has provided a flight verification of upper surface blowing (USB) technology. The A-6 Circulation Control Wing flight demonstration aricraft has provide data for circulation control wing (CCW) technology. Recent small scale wind tunnel model tests and full scale static flow turning test have shown the potential of combining USB with CCW technology. A flight research program is deemed necessary to fully explore the performance and control aspects of CCW jet substitution for the mechanical USB Coanda flap. The required hardware design would also address questions about the development of flight weight ducts and CCW jets and the engine bleed-air capabilities vs requirements. NASA's QSRA would be an optimum flight research vehicle for modification to the USB/CCW configuration. The existing QSRA data base, the design simplicity of the QSRA wing trailing edge controls, availability of engine bleed-air, and the low risk, low cost potential of the suggested program is discussed
Peripapillary and macular choroidal thickness in glaucoma.
PurposeTo compare choroidal thickness (CT) between individuals with and without glaucomatous damage and to explore the association of peripapillary and submacular CT with glaucoma severity using spectral domain optical coherence tomography (SD-OCT).MethodsNinety-one eyes of 20 normal subjects and 43 glaucoma patients from the UCLA SD-OCT Imaging Study were enrolled. Imaging was performed using Cirrus HD-OCT. Choroidal thickness was measured at four predetermined points in the macular and peripapillary regions, and compared between glaucoma and control groups before and after adjusting for potential confounding variables.ResultsThe average (± standard deviation) mean deviation (MD) on visual fields was -0.3 (±2.0) dB in controls and -3.5 (±3.5) dB in glaucoma patients. Age, axial length and their interaction were the most significant factors affecting CT on multivariate analysis. Adjusted average CT (corrected for age, axial length, their interaction, gender and lens status) however, was not different between glaucoma patients and the control group (P=0.083) except in the temporal parafoveal region (P=0.037); nor was choroidal thickness related to glaucoma severity (r=-0.187, P=0.176 for correlation with MD, r=-0.151, P=0.275 for correlation with average nerve fiber layer thickness).ConclusionsChoroidal thickness of the macular and peripapillary regions is not decreased in glaucoma. Anatomical measurements with SD-OCT do not support the possible influence of the choroid on the pathophysiology of glaucoma
Observations Suggesting a Possible Link Between Gammacarboxyglutamic Acid and Porcine Bioprosthetic Valve Calcification
Observations that link gammacarboxyglutamic acid (Gla) peptides with ectopic calcification are accumulating in the literature and may be summarized as follows: 1) Gla peptides selectively bind calcium and hydroxyapatite. 2) The presence of detectable levels of Gla in calcified tissue is concurrent with the onset of mineralization. 3) In an animal model, osteocalcin (a Gla-containing protein) accounts for more than 90% of all the Gla found in the resulting subcutaneously implanted calcified leaflet. 4) Vitamin D stimulates osteocalcin synthesis in cultures of osteosarcoma cells, and in vitamin D deficient rats subcutaneously implanted valve leaflets are not calcified. 5) Gla content and the degree of calcification in degenerated porcine bioprosthetic valves removed from humans are positively correlated. 6) Porcine bioprosthetic valves implanted in children are calcified more rapidly than those of adults, and the normal GIa levels in the urine of children are more than twice those of normal adults
Making a Case for Case-Based Teaching in Data Literacy
Building on a study conducted by the authors, this article provides strategies for teaching data literacy and outlines the case-based teaching method as an effective way of developing data-literate teachers
Asking, Learning, Seeking Out : An Exploration of Data Literacy for Teaching
The current study explored preservice and inservice teachers’ perspectives on data literacy for teaching. Semi-structured interviews were employed with 12 teacher candidates in elementary and special education. The findings revealed participants’ misconceptions regarding formative and summative data; their understanding of the value of formative data; perceptions of challenges related to data literacy for teaching including time, making sense of data, and reliability and validity; and candidates’ preferences for authentic data literacy instruction
Pathogen-specific risk of chronic gastrointestinal disorders following bacterial causes of foodborne illness
BACKGROUND: The US CDC estimates over 2 million foodborne illnesses are annually caused by 4 major enteropathogens: non-typhoid Salmonella spp., Campylobacter spp., Shigella spp. and Yersinia enterocoltica. While data suggest a number of costly and morbid chronic sequelae associated with these infections, pathogen-specific risk estimates are lacking. We utilized a US Department of Defense medical encounter database to evaluate the risk of several gastrointestinal disorders following select foodborne infections. METHODS: We identified subjects with acute gastroenteritis between 1998 to 2009 attributed to Salmonella (nontyphoidal) spp., Shigella spp., Campylobacter spp. or Yersinia enterocolitica and matched each with up to 4 unexposed subjects. Medical history was analyzed for the duration of military service time (or a minimum of 1Â year) to assess for incident chronic gastrointestinal disorders. Relative risks were calculated using modified Poisson regression while controlling for the effect of covariates. RESULTS: A total of 1,753 pathogen-specific gastroenteritis cases (Campylobacter: 738, Salmonella: 624, Shigella: 376, Yersinia: 17) were identified and followed for a median of 3.8Â years. The incidence (per 100,000 person-years) of PI sequelae among exposed was as follows: irritable bowel syndrome (IBS), 3.0; dyspepsia, 1.8; constipation, 3.9; gastroesophageal reflux disease (GERD), 9.7. In multivariate analyses, we found pathogen-specific increased risk of IBS, dyspepsia, constipation and GERD. CONCLUSIONS: These data confirm previous studies demonstrating risk of chronic gastrointestinal sequelae following bacterial enteric infections and highlight additional preventable burden of disease which may inform better food security policies and practices, and prompt further research into pathogenic mechanisms
Standing with our American Indian and Alaska Native Women, Girls, and Two-Spirit People: Exploring the Impact of and Resources for Survivors of Human Trafficking
Despite the violence against Indigenous women, girls, and two-spirit people occurring at epidemic levels there is little national visibility and data pertaining to the lived experiences of American Indian/Alaska Native (AI/AN) individuals and communities. The purpose of this manuscript is to specifically focus on violence regarding the missing and murdered Indigenous women, girls, and two-spirit people with a concentration on human trafficking. AI/AN leaders have identified human trafficking as a major contributor to the disappearance of AI/AN women, girls, and two-spirit people (Department of Justice, 2018). In a trauma-informed intersectional approach we review available data discussing the negative impacts on the brain, the role of complex trauma, and behavioral outcomes while highlighting cultural strengths and resilience. We conclude with culturally relevant and research-informed recommendations to continue to help raise awareness and action to end human trafficking
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Medical interpreter-mediated genetic counseling for Spanish preferring adults at risk for a hereditary cancer syndrome.
The objective of this study was to identify interpretation challenges specific to exome sequencing and errors of potential clinical significance in the context of genetic counseling for adults at risk for a hereditary cancer syndrome. Thirty transcripts of interpreter-mediated telephone results disclosure genetic counseling appointments were coded for errors by bilingual researchers, and the coders applied an overall rating to denote the degree to which the errors interfered with communication overall. Genetic counselors reviewed a subset of errors flagged for potential clinical significance to identify those likely to have clinical impact. Qualitative interviews with 19 interpreters were analyzed to elucidate the challenges they face in interpreting for genetic counseling appointments. Our analysis identified common interpretation errors such as raising the register, omissions, and additions. Further, we found errors specific to genetic counseling concepts and content that appeared to impact the ability of the genetic counselor to accurately assess risk. These errors also may have impacted the patients ability to understand their results, access appropriate follow-up care, and communicate with family members. Among interpreters strengths was the use of requests for clarification; in fact, even more use of clarification would have been beneficial in these encounters. Qualitative interviews surfaced challenges stemming from the structure of interpreter work, such as switching from medical and nonmedical interpretations without substantial breaks. Importantly, while errors were frequent, most did not impede communication overall, and most were not likely to impact clinical care. Nevertheless, potentially clinically impactful errors in communication of genetics concepts may contribute to inequitable care for limited English proficient patients and suggest that additional training in genetics and specialization in healthcare may be warranted. In addition, training for genetic counselors and guidance for patients in working effectively with interpreters could enhance interpreters transmission of complex genetic concepts
Planet Hunters. VIII. Characterization of 41 Long-Period Exoplanet Candidates from Kepler Archival Data
The census of exoplanets is incomplete for orbital distances larger than 1
AU. Here, we present 41 long-period planet candidates in 38 systems identified
by Planet Hunters based on Kepler archival data (Q0-Q17). Among them, 17
exhibit only one transit, 14 have two visible transits and 10 have more than
three visible transits. For planet candidates with only one visible transit, we
estimate their orbital periods based on transit duration and host star
properties. The majority of the planet candidates in this work (75%) have
orbital periods that correspond to distances of 1-3 AU from their host stars.
We conduct follow-up imaging and spectroscopic observations to validate and
characterize planet host stars. In total, we obtain adaptive optics images for
33 stars to search for possible blending sources. Six stars have stellar
companions within 4". We obtain high-resolution spectra for 6 stars to
determine their physical properties. Stellar properties for other stars are
obtained from the NASA Exoplanet Archive and the Kepler Stellar Catalog by
Huber et al. (2014). We validate 7 planet candidates that have planet
confidence over 0.997 (3-{\sigma} level). These validated planets include 3
single-transit planets (KIC-3558849b, KIC-5951458b, and KIC-8540376c), 3
planets with double transits (KIC-8540376b, KIC-9663113b, and KIC-10525077b),
and 1 planet with 4 transits (KIC-5437945b). This work provides assessment
regarding the existence of planets at wide separations and the associated false
positive rate for transiting observation (17%-33%). More than half of the
long-period planets with at least three transits in this paper exhibit transit
timing variations up to 41 hours, which suggest additional components that
dynamically interact with the transiting planet candidates. The nature of these
components can be determined by follow-up radial velocity and transit
observations.Comment: Published on ApJ, 815, 127 Notations of validated planets are changed
in accordance with naming convention of NASA Exoplanet Archiv
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