118 research outputs found
Verification Of High-Resolution Rapid Refresh Surface Winds In Support Of An Open-Source Small Unmanned Aerial Systems Application
Small Uncrewed Aerial Systems (sUAS) can be flown in many conditions under Part 107 of the Federal Aviation Administration (FAA) Code of Regulations. While some weather restrictions exist (visibility, ceiling, and horizontal distance from clouds), subjective flight limits (such as acceptable wind limits) are needed by pilots to ensure safe flight. Multiple websites or applications exist to aid sUAS pilots in decision-making regarding weather for flights, though most are not comprehensive or do little to aid the pilot beyond providing basic weather information. This work evaluates High-Resolution Rapid Refresh (HRRR) forecast wind data in the context of an open-source application to aid sUAS pilots in decision-making. Besides traditional model verification, skill is assessed by evaluating forecasts for specific wind speed thresholds that pilots could use adjust based on their skill level. Finally, bias correction is explored to improve HRRR forecasts.This work finds that systematic biases are present in HRRR surface winds, especially for wind gusts fields. The amount of bias is dependent on land surface type, PBL height, and climatological region. This information is used to understand how forecast output can be improved for the real-world beta test of the sUAS application
Improved small satellite access of the space network
This report contains the results of a study performed under the sponsorship of the National Aeronautics and Space Administration (NASA) made as a grant to the Center for Space Telemetering and Telecommunication Systems at New Mexico State University. The purpose of this phase of the grant is to increase user access to the Space Network (SN) run by NASA for supplying space-to-ground communications for satellites and associated control centers. The identified need is to bring more users into the community of those accessing the SN, especially those in the small satellite class of users. The initial phase of the study concerned the potential for modifications to the standard transponder used in the SN. The results of that investigation are summarized in Section 4. As the hardware modifications were being investigated, a second option was developed, namely to consider changes to the operational mode for the small satellites. This operational concept was to use a single, fixed-pointing antenna in a spin-stabilized satellite and let the antenna pattern sweep past the Tracking and Data Relay Satellites (TDRS) in the SN. The question to be answered by this phase of the study was twofold: could enough contact time per day be made available using this simple operating mode and could the data rate be high enough to allow for sufficient data throughput to satisfy the user community using existing components. Section 2 outlines the methodology and simulation results to answer these questions. Section 3 contains a summary of an operational simulation of a simple satellite payload using these contact scenarios. The simulation is not all inclusive but shows how a payload simulation could be configured to utilize variable contact times. The answer to both of the questions desired to be answered is affirmative. By carefully choosing the correct system transmission power and antenna pattern, the system will allow support to the 50th percentile of expected systems. It is recommended that based on this initial study, further work be done to quantify the exact parameters for transmission through the space network and to optimize usage of the contact time to maximize throughput
Marjolin\u27s Tumor Complicating Chronic Periprosthetic Infection of a Total Knee Arthroplasty
Marjolin\u27s tumor is a term used to describe a malignancy developing in the setting of a chronic wound, infection, or other tissue subject to chronic inflammatory changes. These malignancies usually present after many years of chronicity, and can range from lower grade basal cell carcinomas to high-grade sarcomas. We present the case of a squamous cell carcinoma that developed within a chronic periprosthetic infection of a total knee arthroplasty of 7 years duration. The intra-articular location, association with an orthopaedic implant, and brief latency period are all unique features of this case
A clinical review of robotic navigation in total knee arthroplasty: historical systems to modern design.
Robotic-assisted total knee arthroplasty (RA-TKA) has shown improved reproducibility and precision in mechanical alignment restoration, with improvement in early functional outcomes and 90-day episode of care cost savings compared to conventional TKA in some studies. However, its value is still to be determined.Current studies of RA-TKA systems are limited by short-term follow-up and significant heterogeneity of the available systems.In today\u27s paradigm shift towards an increased emphasis on quality of care while curtailing costs, providing value-based care is the primary goal for healthcare systems and clinicians. As robotic technology continues to develop, longer-term studies evaluating implant survivorship and complications will determine whether the initial capital is offset by improved outcomes.Future studies will have to determine the value of RA-TKA based on longer-term survivorships, patient-reported outcome measures, functional outcomes, and patient satisfaction measures
Unsupervised Home Exercises Versus Formal Physical Therapy After Primary Total Hip Arthroplasty: A Systematic Review
Historically, postoperative exercise and physical therapy (PT) have been viewed as crucial to a successful outcome following primary total hip arthroplasty (THA). This systematic review and meta-analysis aimed to assess differences in both short- and long-term objective and self-reported measures between primary THA patients with formal supervised physical therapy versus unsupervised home exercises after discharge. A search was conducted of six electronic databases from inception to December 14, 2020, for randomized controlled trials (RCTs) comparing changes from baseline in lower extremity strength (LES), aerobic capacity, and self-reported physical function and quality of life (QoL) between supervised and unsupervised physical therapy/exercise regimens following primary THA. Outcomes were separated into short-term (surgery, closest to 3 months) and long-term (≥6 months from surgery, closest to 12 months) measures. Meta-analyses were performed when possible and reported in standardized mean differences (SMDs) with 95% confidence intervals (CI). Seven studies (N=398) were included for review. No significant differences were observed with regard to lower extremity strength (p=0.85), aerobic capacity (p=0.98), or short-term quality of life scores (p=0.18). Although patients in supervised physical therapy demonstrated improved short-term self-reported outcomes compared to those performing unsupervised exercises, this was represented by a small effect size (SMD 0.23 [95% CI, 0.02-0.44]; p=0.04). No differences were observed between groups regarding long-term lower extremity strength (p=0.24), physical outcome scores (p=0.37), or quality of life (p=0.14). The routine use of supervised physical therapy may not provide any clinically significant benefit over unsupervised exercises following primary THA. These results suggest that providers should reconsider the routine use of supervised physical therapy after discharge
Functional gene group analysis indicates no role for heterotrimeric G proteins in cognitive ability
Previous functional gene group analyses implicated common single nucleotide polymorphisms (SNPs) in heterotrimeric G protein coding genes as being associated with differences in human intelligence. Here, we sought to replicate this finding using five independent cohorts of older adults including current IQ and childhood IQ, and using both gene- and SNP-based analytic strategies. No significant associations were found between variation in heterotrimeric G protein genes and intelligence in any cohort at either of the two time points. These results indicate that, whereas G protein systems are important in cognition, common genetic variation in these genes is unlikely to be a substantial influence on human intelligence differences
Psilocybin desynchronizes the human brain
A single dose of psilocybin, a psychedelic that acutely causes distortions of space-time perception and ego dissolution, produces rapid and persistent therapeutic effects in human clinical trials1-4. In animal models, psilocybin induces neuroplasticity in cortex and hippocampus5-8. It remains unclear how human brain network changes relate to subjective and lasting effects of psychedelics. Here we tracked individual-specific brain changes with longitudinal precision functional mapping (roughly 18 magnetic resonance imaging visits per participant). Healthy adults were tracked before, during and for 3 weeks after high-dose psilocybin (25 mg) and methylphenidate (40 mg), and brought back for an additional psilocybin dose 6-12 months later. Psilocybin massively disrupted functional connectivity (FC) in cortex and subcortex, acutely causing more than threefold greater change than methylphenidate. These FC changes were driven by brain desynchronization across spatial scales (areal, global), which dissolved network distinctions by reducing correlations within and anticorrelations between networks. Psilocybin-driven FC changes were strongest in the default mode network, which is connected to the anterior hippocampus and is thought to create our sense of space, time and self. Individual differences in FC changes were strongly linked to the subjective psychedelic experience. Performing a perceptual task reduced psilocybin-driven FC changes. Psilocybin caused persistent decrease in FC between the anterior hippocampus and default mode network, lasting for weeks. Persistent reduction of hippocampal-default mode network connectivity may represent a neuroanatomical and mechanistic correlate of the proplasticity and therapeutic effects of psychedelics
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
- …