1,851 research outputs found

    An Investigation of the Overlap Between the Statistical Discrete Gust and the Power Spectral Density Analysis Methods

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    The results of a NASA investigation of a claimed Overlap between two gust response analysis methods: the Statistical Discrete Gust (SDG) Method and the Power Spectral Density (PSD) Method are presented. The claim is that the ratio of an SDG response to the corresponding PSD response is 10.4. Analytical results presented for several different airplanes at several different flight conditions indicate that such an Overlap does appear to exist. However, the claim was not met precisely: a scatter of up to about 10 percent about the 10.4 factor can be expected

    What does it mean to be “prepared for work”? Perceptions of new engineers

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    Background: Engineering education seeks to prepare students for engineering practice, but the concept of preparedness is often ill-defined. Moreover, findings from studies of different populations or in different contexts vary regarding how well new graduates are prepared. These variations, coupled with the lack of clarity, suggest the need to better understand what it means to be prepared for engineering work. Purpose: This study contributes to research on workplace preparation by exploring how new graduates describe being prepared for engineering work. Method: Applying secondary analysis to data from the multi-institution Capstone To Work (C2W) project, we used thematic analysis to explore new engineers\u27 descriptions of preparedness. We analyzed written responses to structured questions about the school-to-work transition collected weekly during participants\u27 first 12 weeks of work; 105 graduates drawn from four universities provided 956 responses, with a mean of 9 (out of 12 possible) responses per participant. Results: Participants\u27 descriptions of preparedness included applying concrete skills, recognizing familiar situations, and having strategies for approaching challenging tasks even when they lacked relevant knowledge or skill. Conclusion: Our findings suggest that although many discussions about workplace preparation implicitly focus narrowly on mastery of skills and knowledge, that focus may not fully capture new graduates\u27 experiences, and may limit discussions about the ways in which school can (and cannot) prepare students for work. A more expansive understanding may better support both student learning and workplace onboarding, though more research is needed across stakeholders to establish shared understanding

    Extra-articular arthroscopic release of lateral epicondylitis: a prospective study

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    Background: Operative management of lateral epicondylitis can be managed with percutaneous, arthroscopic, or open surgical release. Extraarticular arthroscopic release is a new technique, and no study has compared its outcomes and risk profile. Methods: A 26-patient cohort was reviewed before and after extraarticular arthroscopic release, which was performed by the senior author. The Mayo Elbow Performance Scores were used as a functional outcome score and obtained via a phone interview. Results were analyzed using a paired t-test with a statistical significance set at P \u3c .05. Results: Of the 26 patients, 10 were being treated under workers compensation. Preoperative Mayo Elbow Performance Score was 47.5, and the postoperative score was 90.2 with a significant difference of 42.7 (P value 1⁄4 .05). The workers compensation group scored 13.3 points lower postoperatively than the remainder of patients, which was shown to also be significant with a P value of .002. Discussion and Conclusion: The advantage of extraarticular arthroscopic release was better visualiza- tion of affected structures, which improved accuracy of debridement, and a small capsulotomy, which decreased the risk of a transient radial nerve palsy. Overall, extraarticular arthroscopic results were found to be good and comparable to the results of other operative techniques with the added advantage of a lower risk profile

    Staphylococcus aureus Nasal Carriage among Beefpacking Workers in a Midwestern United States Slaughterhouse

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    Occupational contact with livestock is an established risk factor for exposure to livestock-associated methicillin-resistant Staphylococcus aureus (MRSA), particularly among industrial swine workers. While S. aureus is known to infect cattle, livestock-associated S. aureuscarriage among workers in the beef production chain has received limited attention. Beefpacking workers, who slaughter, butcher and process cattle, have intensified exposure to potentially infectious animal materials and may be at risk of livestock-associated S. aureusexposure. We conducted a cross-sectional study of beefpacking workers (n = 137) at an industrial slaughterhouse in the Midwestern United States to evaluate prevalence and characteristics of S. aureus nasal colonization, specifically the absence of the scn gene to identify putative association with livestock, antibiotic susceptibility, presence of Panton-Valentin leukocidin (PVL) genes lukS-PV and lukF-PV, and spa type. Overall prevalence of S.aureus nasal carriage was 27.0%. No workers carried livestock-associated MRSA. Methicillin-sensitive S. aureus isolates (MSSA) recovered from five workers (3.6%) lacked the scn gene and were considered putative livestock-associated S. aureus (pLA-SA). Among pLA-SA isolates, spa types t338, t748, t1476 and t2379 were identified. To our knowledge, these spatypes have not previously been identified as associated with livestock. Prevalence of human-adapted MRSA carriage in workers was 3.6%. MRSA isolates were identified as spa types t002, t008 and t024, and four of five MRSA isolates were PVL-positive. To date, this is the first study to indicate that industrial beefpacking workers in the United States may be exposed to livestock-associated S. aureus, notably MSSA, and to spa types not previously identified in livestock and livestock workers. Occupational exposure to livestock-associated S. aureus in the beef production chain requires further epidemiologic investigation

    Primary Care Provider Perceptions of Colorectal Cancer Screening Barriers: Implications for Designing Quality Improvement Interventions

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    Aims. Colorectal cancer (CRC) screening is underutilized. Increasing CRC screening rates requires interventions targeting multiple barriers at each level of the healthcare organization (patient, provider, and system). We examined groups of primary care providers (PCPs) based on perceptions of screening barriers and the relationship to CRC screening rates to inform approaches for conducting barrier assessments prior to designing and implementing quality improvement interventions. Methods. We conducted a retrospective cohort study linking EHR and survey data. PCPs with complete survey responses for questions addressing CRC screening barriers were included (N=166 PCPs; 39,430 patients eligible for CRC screening). Cluster analysis identified groups of PCPs. Multivariate logistic regression estimated odds ratios and 95% confidence intervals for predictors of membership in one of the PCP groups. Results. We found two distinct groups: (1) PCPs identifying multiple barriers to CRC screening at patient, provider, and system levels (N=75) and (2) PCPs identifying no major barriers to screening (N=91). PCPs in the top half of CRC screening performance were more likely to identify multiple barriers than the bottom performers (OR, 4.14; 95% CI, 2.43–7.08). Conclusions. High-performing PCPs can more effectively identify CRC screening barriers. Targeting high-performers when conducting a barrier assessment is a novel approach to assist in designing quality improvement interventions for CRC screening

    The food choice at work study: effectiveness of complex workplace dietary interventions on dietary behaviours and diet-related disease risk - study protocol for a clustered controlled trial

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    Background: Dietary behaviour interventions have the potential to reduce diet-related disease. Ample opportunity exists to implement these interventions in the workplace. The overall aim is to assess the effectiveness and cost-effectiveness of complex dietary interventions focused on environmental dietary modification alone or in combination with nutrition education in large manufacturing workplace settings. Methods/design: A clustered controlled trial involving four large multinational manufacturing workplaces in Cork will be conducted. The complex intervention design has been developed using the Medical Research Council's framework and the National Institute for Health and Clinical Excellence (NICE) guidelines and will be reported using the TREND statement for the transparent reporting of evaluations with non-randomized designs. It will draw on a soft paternalistic 'nudge' theoretical perspective. It will draw on a soft paternalistic "nudge" theoretical perspective. Nutrition education will include three elements: group presentations, individual nutrition consultations and detailed nutrition information. Environmental dietary modification will consist of five elements: (a) restriction of fat, saturated fat, sugar and salt, (b) increase in fibre, fruit and vegetables, (c) price discounts for whole fresh fruit, (d) strategic positioning of healthier alternatives and (e) portion size control. No intervention will be offered in workplace A (control). Workplace B will receive nutrition education. Workplace C will receive nutrition education and environmental dietary modification. Workplace D will receive environmental dietary modification alone. A total of 448 participants aged 18 to 64 years will be selected randomly. All permanent, full-time employees, purchasing at least one main meal in the workplace daily, will be eligible. Changes in dietary behaviours, nutrition knowledge, health status with measurements obtained at baseline and at intervals of 3 to 4 months, 7 to 9 months and 13 to 16 months will be recorded. A process evaluation and cost-effectiveness economic evaluation will be undertaken. Discussion: A 'Food Choice at Work' toolbox (concise teaching kit to replicate the intervention) will be developed to inform and guide future researchers, workplace stakeholders, policy makers and the food industry. Trial registration: Current Controlled Trials, ISRCTN35108237

    Mid-to-Late M Dwarfs Lack Jupiter Analogs

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    Cold Jovian planets play an important role in sculpting the dynamical environment in which inner terrestrial planets form. The core accretion model predicts that giant planets cannot form around low-mass M dwarfs, although this idea has been challenged by recent planet discoveries. Here, we investigate the occurrence rate of giant planets around low-mass (0.1-0.3M_\odot) M dwarfs. We monitor a volume-complete, inactive sample of 200 such stars located within 15 parsecs, collecting four high-resolution spectra of each M dwarf over six years and performing intensive follow-up monitoring of two candidate radial-velocity variables. We use TRES on the 1.5 m telescope at the Fred Lawrence Whipple Observatory and CHIRON on the Cerro Tololo Inter-American Observatory 1.5 m telescope for our primary campaign, and MAROON-X on Gemini North for high-precision follow-up. We place a 95%-confidence upper limit of 1.5% (68%-confidence limit of 0.57%) on the occurrence of MPM_{\rm P}sini>i > 1MJ_{\rm J} giant planets out to the water snow line and provide additional constraints on the giant planet population as a function of MPM_{\rm P}sinii and period. Beyond the snow line (100100 K <Teq<150< T_{\rm eq} < 150 K), we place 95%-confidence upper limits of 1.5%, 1.7%, and 4.4% (68%-confidence limits of 0.58%, 0.66%, and 1.7%) for 3MJ<MP_{\rm J} < M_{\rm P}sini<10i < 10MJ_{\rm J}, 0.8MJ<MP_{\rm J} < M_{\rm P}sini<3i < 3MJ_{\rm J}, and 0.3MJ<MP_{\rm J} < M_{\rm P}sini<0.8i < 0.8MJ_{\rm J} giant planets; i.e., Jupiter analogs are rare around low-mass M dwarfs. In contrast, surveys of Sun-like stars have found that their giant planets are most common at these Jupiter-like instellations.Comment: Accepted for publication in AJ; 19 pages, 5 figures, 2 table

    Identification of Mutant Genes and Introgressed Tiger Salamander DNA in the Laboratory Axolotl, \u3cem\u3eAmbystoma mexicanum\u3c/em\u3e

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    The molecular genetic toolkit of the Mexican axolotl, a classic model organism, has matured to the point where it is now possible to identify genes for mutant phenotypes. We used a positional cloning–candidate gene approach to identify molecular bases for two historic axolotl pigment phenotypes: white and albino. White (d/d) mutants have defects in pigment cell morphogenesis and differentiation, whereas albino (a/a) mutants lack melanin. We identified in white mutants a transcriptional defect in endothelin 3 (edn3), encoding a peptide factor that promotes pigment cell migration and differentiation in other vertebrates. Transgenic restoration of Edn3 expression rescued the homozygous white mutant phenotype. We mapped the albino locus to tyrosinase (tyr) and identified polymorphisms shared between the albino allele (tyra) and tyr alleles in a Minnesota population of tiger salamanders from which the albino trait was introgressed. tyra has a 142 bp deletion and similar engineered alleles recapitulated the albinophenotype. Finally, we show that historical introgression of tyrasignificantly altered genomic composition of the laboratory axolotl, yielding a distinct, hybrid strain of ambystomatid salamander. Our results demonstrate the feasibility of identifying genes for traits in the laboratory Mexican axolotl

    The K2 & TESS Synergy II: Revisiting 26 systems in the TESS Primary Mission

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    The legacy of NASA's K2 mission has provided hundreds of transiting exoplanets that can be revisited by new and future facilities for further characterization, with a particular focus on studying the atmospheres of these systems. However, the majority of K2-discovered exoplanets have typical uncertainties on future times of transit within the next decade of greater than four hours, making observations less practical for many upcoming facilities. Fortunately, NASA's Transiting exoplanet Survey Satellite (TESS) mission is reobserving most of the sky, providing the opportunity to update the ephemerides for \sim300 K2 systems. In the second paper of this series, we reanalyze 26 single-planet, K2-discovered systems that were observed in the TESS primary mission by globally fitting their K2 and TESS lightcurves (including extended mission data where available), along with any archival radial velocity measurements. As a result of the faintness of the K2 sample, 13 systems studied here do not have transits detectable by TESS. In those cases, we re-fit the K2 lightcurve and provide updated system parameters. For the 23 systems with M0.6MM_* \gtrsim 0.6 M_\odot, we determine the host star parameters using a combination of Gaia parallaxes, Spectral Energy Distribution (SED) fits, and MESA Isochrones and Stellar Tracks (MIST) stellar evolution models. Given the expectation of future TESS extended missions, efforts like the K2 & TESS Synergy project will ensure the accessibility of transiting planets for future characterization while leading to a self-consistent catalog of stellar and planetary parameters for future population efforts.Comment: Accepted for publication in ApJ. 29 pages, 9 figures, 12 table

    Three red suns in the sky: A transiting, terrestrial planet in a triple M-dwarf system at 6.9 pc

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    We present the discovery from Transiting Exoplanet Survey Satellite (TESS) data of LTT 1445Ab. At a distance of 6.9 pc, it is the second nearest transiting exoplanet system found to date, and the closest one known for which the primary is an M dwarf. The host stellar system consists of three mid-to-late M dwarfs in a hierarchical configuration, which are blended in one TESS pixel. We use MEarth data and results from the Science Processing Operations Center data validation report to determine that the planet transits the primary star in the system. The planet has a radius of 1.380.12+0.13{1.38}_{-0.12}^{+0.13} R{R}_{\oplus }, an orbital period of 5.358820.00031+0.00030{5.35882}_{-0.00031}^{+0.00030} days, and an equilibrium temperature of 43327+28{433}_{-27}^{+28} K. With radial velocities from the High Accuracy Radial Velocity Planet Searcher, we place a 3σ upper mass limit of 8.4 M{M}_{\oplus } on the planet. LTT 1445Ab provides one of the best opportunities to date for the spectroscopic study of the atmosphere of a terrestrial world. We also present a detailed characterization of the host stellar system. We use high-resolution spectroscopy and imaging to rule out the presence of any other close stellar or brown dwarf companions. Nineteen years of photometric monitoring of A and BC indicate a moderate amount of variability, in agreement with that observed in the TESS light-curve data. We derive a preliminary astrometric orbit for the BC pair that reveals an edge-on and eccentric configuration. The presence of a transiting planet in this system hints that the entire system may be co-planar, implying that the system may have formed from the early fragmentation of an individual protostellar core.Accepted manuscrip
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