1,295 research outputs found

    Martian surface physical properties to be derived by radar altimeter on the Mars observer spacecraft

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    The potential is described of a candidate Mars Observer altimeter for determining dielectric properties of Mars regolith. It is pointed out that it is straightforward to use the time between altimeter pulse trains for passive radiometry (hence dielectric properties) and roughness can be derived. Given the mission plan the whole surface can be mapped at least three times, yielding data on seasonal variability

    Sedimentology of Martian Gravels from Mardi Twilight Imaging: Techniques

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    Quantitative sedimentologic analysis of gravel surfaces dominated by pebble-sized clasts has been employed in an effort to untangle aspects of the provenance of surface sediments on Mars using Curiosity's MARDI nadir-viewing camera operated at twilight Images have been systematically acquired since sol 310 providing a representative sample of gravel-covered surfaces since the rover departed the Shaler region. The MARDI Twilight imaging dataset offers approximately 1 millimeter spatial resolution (slightly out of focus) for patches beneath the rover that cover just under 1 m2 in area, under illumination that makes clast size and inter-clast spacing analysis relatively straightforward using semi- automated codes developed for use with nadir images. Twilight images are utilized for these analyses in order to reduce light scattering off dust deposited on the front MARDI lens element during the terminal stages of Curiosity's entry, descent and landing. Such scattering is worse when imaging bright, directly-illuminated surfaces; twilight imaging times yield diffusely-illuminated surfaces that improve the clarity of the resulting MARDI product. Twilight images are obtained between 10-30 minutes after local sunset, governed by the timing of the end of the no-heat window for the camera. Techniques were also utilized to examine data terrestrial locations (the Kau Desert in Hawaii and near Askja Caldera in Iceland). Methods employed include log hyperbolic size distribution (LHD) analysis and Delauney Triangulation (DT) inter-clast spacing analysis. This work extends the initial results reported in Yingst et al., that covered the initial landing zone, to the Rapid-Transit Route (RTR) towards Mount Sharp

    A Vision for the Exploration of Mars: Robotic Precursors Followed by Humans to Mars Orbit in 2033

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    The reformulation of the Mars program gives NASA a rare opportunity to deliver a credible vision in which humans, robots, and advancements in information technology combine to open the deep space frontier to Mars. There is a broad challenge in the reformulation of the Mars exploration program that truly sets the stage for: 'a strategic collaboration between the Science Mission Directorate (SMD), the Human Exploration and Operations Mission Directorate (HEOMD) and the Office of the Chief Technologist, for the next several decades of exploring Mars'.Any strategy that links all three challenge areas listed into a true long term strategic program necessitates discussion. NASA's SMD and HEOMD should accept the President's challenge and vision by developing an integrated program that will enable a human expedition to Mars orbit in 2033 with the goal of returning samples suitable for addressing the question of whether life exists or ever existed on Mar

    Infrastructure for Retinal Image Analysis

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    This paper introduces a retinal image analysis infrastructure for the automatic assessment of biomarkers related to early signs of diabetes, hypertension and other systemic diseases. The developed application provides several tools, namely normalization, vessel enhancement and segmentation, optic disc and fovea detection, junction detection, bifurcation/crossing discrimination, artery/vein classification and red lesion detection. The pipeline of these methods allows the assessment of important biomarkers characterizing dynamic properties of retinal vessels, such as tortuosity, width, fractal dimension and bifurcation geometry features

    Physiological genetics of aluminum tolerance in the wheat cultivar Atlas 66

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    Aluminum toxicity limits wheat (Triticum aestivum L.) production on acidic soils. The wheat cultivar Atlas 66 reportedly may have both more than one Al tolerance gene and more than one Al tolerance mechanism. The purpose of this study was to identify the Al tolerance mechanisms conferred by the individual Atlas 66 Al tolerance genes present in near-isogenic lines (NILs) of the cv. Century and Chisholm ('Century-T' and 'Chisholm-T'). Seedling hydroponic culture analysis revealed that the NILs were not as Al tolerant, nor were they able to exclude Al from root apices as effectively as Atlas 66. Al-inducible malate release from root apices was significantly higher in the NILs compared with the recurrent parents, but less than that observed in Atlas 66. In contrast, root phosphate release was significantly lower than previously reported in Atlas 66, with no major differences observed among lines. These results indicate that the Atlas 66 Al tolerance gene present in each NIL acts by increasing Al-inducible malate release from root tips, but confers only a portion of the Al tolerance of Atlas 66 in both instances. Thus, differences in Al tolerance between the NILs and Atlas 66 can be attributed to malate release differences, and not differential phosphate release. Further, these results indicate that genetic variation at more than one locus underlies the malate- mediated Al tolerance differences in Atlas 66, when compared with Century and Chisholm. The Atlas 66 alleles for these loci have not been introgressed into the NILs.Peer reviewedPlant and Soil Science

    Stratified primary care versus non-stratified care for musculoskeletal pain: findings from the STarT MSK feasibility and pilot cluster randomized controlled trial

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    Background: Musculoskeletal (MSK) pain from the five most common presentations to primary care (back, neck, shoulder, knee or multi-site pain), where the majority of patients are managed, is a costly global health challenge. At present, first-line decisionmaking is based on clinical reasoning and stratified models of care have only been tested in patients with low back pain. We therefore, examined the feasibility of; a) a future definitive cluster randomised controlled trial (RCT), and b) General Practitioners (GPs) providing stratified care at the point-of-consultation for these five most common MSK pain presentations. Methods: The design was a pragmatic pilot, two parallel-arm (stratified versus nonstratified care), cluster RCT and the setting was 8 UK GP practices (4 intervention, 4 control) with randomisation (stratified by practice size) and blinding of trial statistician and outcome data-collectors. Participants were adult consulters with MSK pain without indicators of serious pathologies, urgent medical needs, or vulnerabilities. Potential participant records were tagged and individuals sent postal invitations using a GP point-of-consultation electronic medical record (EMR) template. The intervention was supported by the EMR template housing the Keele STarT MSK Tool (to stratify into low, medium and high-risk prognostic subgroups of persistent pain and disability) and recommended matched treatment options. Feasibility outcomes included exploration of recruitment and follow-up rates, selection bias, and GP intervention fidelity. To capture recommended outcomes including pain and function, participants completed an initial questionnaire, brief monthly questionnaire (postal or SMS), and 6-month follow-up questionnaire. An anonymised EMR audit described GP decision-making. Results: GPs screened 3063 patients (intervention=1591, control=1472), completed the EMR template with 1237 eligible patients (intervention=513, control=724) and 524 participants (42%) consented to data collection (intervention=231, control=293). Recruitment took 28 weeks (target 12 weeks) with >90% follow-up retention (target >75%). We detected no selection bias of concern and no harms identified. GP stratification tool fidelity failed to achieve a-priori success criteria, whilst fidelity to the matched treatments achieved “complete success”. Conclusions: A future definitive cluster RCT of stratified care for MSK pain is feasible and is underway, following key amendments including a clinician-completed version of the stratification tool and refinements to recommended matched treatments

    Computer-Based Stratified Primary Care for Musculoskeletal Consultations Compared With Usual Care: Study Protocol for the STarT MSK Cluster Randomized Controlled Trial.

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    BACKGROUND: Musculoskeletal (MSK) pain is a major cause of pain and disability. We previously developed a prognostic tool (STarT Back Tool) with demonstrated effectiveness in guiding primary care low back pain management by supporting decision-making using matched treatments. A logical next step is to determine whether prognostic stratified care has benefits for a broader range of common MSK pain presentations. OBJECTIVE: This study seeks to determine, in patients with 1 of the 5 most common MSK presentations (back, neck, knee, shoulder, and multisite pain), whether stratified care involving the use of the Keele STarT MSK Tool to allocate individuals into low-, medium-, and high-risk subgroups, and matching these subgroups to recommended matched clinical management options, is clinical and cost effective compared with usual nonstratified primary care. METHODS: This is a pragmatic, two-arm parallel (stratified vs nonstratified care), cluster randomized controlled trial, with a health economic analysis and mixed methods process evaluation. The setting is UK primary care, involving 24 average-sized general practices randomized (stratified by practice size) in a 1:1 ratio (12 per arm) with blinding of trial statistician and outcome data collectors. Randomization units are general practices, and units of observation are adult MSK consulters without indicators of serious pathologies, urgent medical needs, or vulnerabilities. Potential participant records are tagged and individuals invited using a general practitioner (GP) point-of-consultation electronic medical record (EMR) template. The intervention is supported by an EMR template (computer-based) housing the Keele STarT MSK Tool (to stratify into prognostic subgroups) and the recommended matched treatment options. The primary outcome using intention-to-treat analysis is pain intensity, measured monthly over 6 months. Secondary outcomes include physical function and quality of life, and an anonymized EMR audit to capture clinician decision making. The economic evaluation is focused on the estimation of incremental quality-adjusted life years and MSK pain-related health care costs. The process evaluation is exploring a range of potential factors influencing the intervention and understanding how it is perceived by patients and clinicians, with quantitative analyses focusing on a priori hypothesized intervention targets and qualitative approaches using focus groups and interviews. The target sample size is 1200 patients from 24 general practices, with >5000 MSK consultations available for anonymized medical record data comparisons. RESULTS: Trial recruitment commenced on May 18, 2018, and ended on July 15, 2019, after a 14-month recruitment period in 24 GP practices. Follow-up and interview data collection was completed in February 2020. CONCLUSIONS: This trial is the first attempt, as far as we know, at testing a prognostic stratified care approach for primary care patients with MSK pain. The results of this trial should be available by the summer of 2020. CLINICALTRIAL: International Standard Randomized Controlled Trial Number (ISRCTN): 15366334; http://www.isrctn.com/ISRCTN15366334

    TQM and performance appraisal : complementary or incompatible?

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    Despite the scholarly interest in performance management as a key determinant of the effectiveness of enterprise process improvement methods such as total quality management (TQM) and its derivatives, few empirical studies have explicitly explored the practice of performance management systems in TQM‐focused organizations. In order to redress this imbalance, this study aims to describe how organizational and managerial forces led to a performance management systems failing to embrace the core principles of process improvement methods such as TQM. Using a qualitative study of six large UK‐based automobile and auto parts manufacturers, our results illustrate how manager‐controlled, individual‐focused, past‐oriented, long‐cycle, and narrowly defined performance appraisal (PA) systems can intervene to underline the ultimate potential of TQM. The paper concludes with the discussion of implications for theory and practice of TQM and human resource performance management
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