253 research outputs found

    Designing Volumetric Truss Structures

    Full text link
    We present the first algorithm for designing volumetric Michell Trusses. Our method uses a parametrization approach to generate trusses made of structural elements aligned with the primary direction of an object's stress field. Such trusses exhibit high strength-to-weight ratios. We demonstrate the structural robustness of our designs via a posteriori physical simulation. We believe our algorithm serves as an important complement to existing structural optimization tools and as a novel standalone design tool itself

    The Effect of Hospital Volume on Mortality in Patients Admitted with Severe Sepsis

    Get PDF
    Importance The association between hospital volume and inpatient mortality for severe sepsis is unclear. Objective: To assess the effect of severe sepsis case volume and inpatient mortality. Design Setting and Participants Retrospective cohort study from 646,988 patient discharges with severe sepsis from 3,487 hospitals in the Nationwide Inpatient Sample from 2002 to 2011. Exposures The exposure of interest was the mean yearly sepsis case volume per hospital divided into tertiles. Main Outcomes and Measures Inpatient mortality. Results: Compared with the highest tertile of severe sepsis volume (>60 cases per year), the odds ratio for inpatient mortality among persons admitted to hospitals in the lowest tertile (≤10 severe sepsis cases per year) was 1.188 (95% CI: 1.074–1.315), while the odds ratio was 1.090 (95% CI: 1.031–1.152) for patients admitted to hospitals in the middle tertile. Similarly, improved survival was seen across the tertiles with an adjusted inpatient mortality incidence of 35.81 (95% CI: 33.64–38.03) for hospitals with the lowest volume of severe sepsis cases and a drop to 32.07 (95% CI: 31.51–32.64) for hospitals with the highest volume. Conclusions and Relevance We demonstrate an association between a higher severe sepsis case volume and decreased mortality. The need for a systems-based approach for improved outcomes may require a high volume of severely septic patients

    The effect of a one-time 15-minute guided meditation (Isha Kriya) on stress and mood disturbances among operating room professionals: a prospective interventional pilot study

    Get PDF
    Background: Operating room professionals are exposed to high levels of stress and burnout. Besides affecting the individual, it can compromise patient safety and quality of care as well. Meditation practice is getting recognized for its ability to improve wellness among various populations, including healthcare providers. Methods: Baseline stress levels of perioperative healthcare providers were measured via an online survey using a Perceived Stress Scale (PSS) questionnaire. An in-person meditation workshop was demonstrated during surgical grand rounds and an international anesthesia conference using a 15-minute guided Isha Kriya meditation. The participants were then surveyed for mood changes before and after meditation using a Profile of Mood States (POMS) questionnaire. Results: Surgeons and anesthesiologists were found to have higher median (interquartile range) Perceived Stress Scores as compared to nurses respectively (17 [12, 20] and 17 [12, 21] vs 14 [9, 19]; P = 0.01). Total mood disturbances were found to be significantly reduced after meditation in both the surgical grand rounds (pre-meditation median [IQR] 99 [85, 112] vs 87 [80, 93] post-meditation; P < 0.0001) and anesthesia conference cohorts (pre-meditation 92 [86, 106] vs 87 [81, 92] post-meditation; P < 0.0001). Conclusions: Isha Kriya, a guided meditation, is easy to learn and takes less than 15 minutes to complete. This meditation technique improves mood changes and negative emotions among operating room professionals and could be used as a potential tool for improving wellness

    The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey:Constraining modified gravity

    Get PDF
    We use baryon acoustic oscillation and redshift space distortion from the completed Baryon Oscillation Spectroscopic Survey, corresponding to data release 12 of the Sloan Digital Sky Survey, combined sample analysis in combination with cosmic microwave background, supernova and redshift space distortion measurements from additional spectroscopic surveys to test deviations from general relativity. We present constraints on several phenomenological models of modified gravity: First, we parametrise the growth of structure using the growth index γ\gamma, finding γ=0.566±0.058\gamma=0.566\pm0.058 (68\% C.L.). Second, we modify the relation of the two Newtonian potentials by introducing two additional parameters, GMG_M and GLG_L. In this approach, GMG_M refers to modifications of the growth of structure whereas GLG_L to modification of the lensing potential. We consider a power law to model the redshift dependency of GMG_M and GLG_L as well as binning in redshift space, introducing four additional degrees of freedom, GM(z0.5)G_M(z0.5), GL(z0.5)G_L(z0.5). At 68\% C.L. we measure GM=0.980±0.096G_M=0.980 \pm 0.096 and GL=1.082±0.060G_L=1.082 \pm 0.060 for a linear model, GM=1.01±0.36G_M= 1.01\pm 0.36 and GL=1.31±0.19G_L=1.31 \pm 0.19 for a cubic model as well as GM(z<0.5)=1.26±0.32G_M(z<0.5)=1.26 \pm 0.32, GM(z>0.5)=0.986±0.022G_M(z>0.5)=0.986\pm0.022, GL(z<0.5)=1.067±0.058G_L(z<0.5)=1.067\pm0.058 and GL(z>0.5)=1.037±0.029G_L(z>0.5)=1.037\pm0.029. Thirdly, we investigate general scalar tensor theories of gravity, finding the model to be mostly unconstrained by current data. Assuming a one-parameter f(R)f(R) model we can constrain B0<7.7×105B_0< 7.7 \times 10^{-5} (95\% C.L). For all models we considered we find good agreement with general relativity.Comment: 10 pages, 7 figures, submitted to MNRA

    The clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey DR14 quasar sample : measuring the evolution of the growth rate using redshift-space distortions between redshift 0.8 and 2.2

    Get PDF
    Funding: RR and WJP acknowledge support from the European Research Council through the Darksurvey grant 614030. WJP also acknowledges support from the UK Science and Technology Facilities Council grant ST/N000668/1, and the UK Space Agency grant ST/N00180X/1. Funding for SDSS-III and SDSS-IV has been provided by the Alfred P. Sloan Foundation and Participating Institutions. Additional funding for SDSS-III comes from the National Science Foundationa nd the U.S. Department of Energy Office of Science.We measure the growth rate and its evolution using the anisotropic clustering of the extended Baryon Oscillation Spectroscopic Survey (eBOSS) Data Release 14 (DR14) quasar sample, which includes 148 659 quasars covering the wide redshift range of 0.8 < z < 2.2 and a sky area of 2112.90 deg2. To optimize measurements we deploy a redshift-dependent weighting scheme, which allows us to avoid binning and perform the data analysis consistently including the redshift evolution across the sample. We perform the analysis in Fourier space, and use the redshift evolving power spectrum multipoles to measure the redshift-space distortion parameter fσ8 and parameters controlling the anisotropic projection of the cosmological perturbations. We measure fσ8(z = 1.52) = 0.43 ± 0.05 and dfσ8/dz(z = 1.52) = -0.16 ± 0.08, consistent with the expectation for a lambda cold dark matter cosmology as constrained by the Planck experiment.Publisher PDFPeer reviewe

    Rapid weight gain and weight differential predict competitive success in 2100 professional combat-sport athletes.

    Get PDF
    Purpose: Combat-sport athletes commonly undergo rapid weight loss prior to prebout weigh-in and subsequently rapid weight gain (RWG) prior to competition. This investigation aimed to evaluate the effect of RWG and weight differential (WD) between opponents on competitive success. Methods: A retrospective cohort study was performed using data from professional mixed martial arts (MMA) and boxing events held between 2015 and 2019. The primary outcome was RWG (relative and absolute) between weigh-in and competition stratified by bout winners and losers. Binary logistic regression was used to explore the relationships among bout outcome, RWG, and WD between competitors on the day of their bout. Results: Among 708 MMA athletes included, winners regained more relative body mass (8.7% [3.7%] vs 7.9% [3.8%], P < .01) than losers. In 1392 included male boxers, winners regained significantly more relative body mass (8.0% [3.0%] vs 6.9% [3.2%], P < .01) than losers. Each percentage body mass increase resulted in a 7% increased likelihood of victory in MMA and a 13% increase in boxing. The relationship between RWG and competitive success remained significant in regional and male international MMA athletes, as well as boxers. WD predicted victory in international mixed martial artists and boxers. WD predicted victory by knockout or technical knockout in international MMA athletes and regional boxers. Conclusion: This analysis of combat-sport athletes indicates that RWG and WD influence competitive success. These findings raise fair-play and safety concerns in these popular sports and may help guide risk-mitigating regulation strategies

    The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

    Get PDF
    The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected

    Epidemiology, Molecular Characterization and Antibiotic Resistance of Neisseria meningitidis from Patients ≤15 Years in Manhiça, Rural Mozambique

    Get PDF
    BACKGROUND: The epidemiology of meningococcal disease in Mozambique and other African countries located outside the "meningitis belt" remains widely unknown. With the event of upcoming vaccines microbiological and epidemiological information is urgently needed. METHODS: Prospective surveillance for invasive bacterial infections was conducted at the Manhiça District hospital (rural Mozambique) among hospitalized children below 15 years of age. Available Neisseria meningitidis isolates were serogrouped and characterized by Multilocus Sequence Typing (MLST). Antibiotic resistance was also determined. RESULTS: Between 1998 and 2008, sixty-three cases of confirmed meningococcal disease (36 meningitis, 26 sepsis and 1 conjunctivitis) were identified among hospitalized children. The average incidence rate of meningococcal disease was 11.6/100,000 (8/100,000 for meningitis and 3.7/100,000 for meningococcemia, respectively). There was a significant rise on the number of meningococcal disease cases in 2005-2006 that was sustained till the end of the surveillance period. Serogroup was determined for 43 of the 63 meningococcal disease cases: 38 serogroup W-135, 3 serogroup A and 2 serogroup Y. ST-11 was the most predominant sequence type and strongly associated with serogroup W-135. Two of the three serogroup A isolates were ST-1, and both serogroup Y isolates were ST-175. N. meningitidis remained highly susceptible to all antibiotics used for treatment in the country, although the presence of isolates presenting intermediate resistance to penicillin advocates for continued surveillance. CONCLUSIONS: Our data show a high rate of meningococcal disease in Manhiça, Mozambique, mainly caused by serogroup W-135 ST-11 strains, and advocates for the implementation of a vaccination strategy covering serogroup W-135 meningococci in the country
    corecore