12,408 research outputs found
Uncertainties for Pre- and Post-Launch Radiometric Calibration of Imaging Spectrometers for Multi-Sensor Applications
An important aspect to using imaging spectrometer data is the radiometric characterization and calibration of the sensors and validation of their data products and doing so with error budgets with known traceability. The radiometric accuracy of a given sensor is important for demonstrating the expected quality of data from the sensor. Known traceability allows data from multiple sensors to be directly comparable as will become more important in the near future with the expected launches of multiple imaging spectrometers from multiple countries, agencies, and commercial entities. The current work describes the state of pre- and post-launch radiometric absolute and relative uncertainties and their role in harmonising on-orbit data. Examples of prelaunch uncertainties based on the calibration of EnMAP and the calibration planned for the CLARREO Pathfinder Mission are presented highlighting recent work in the area of detector-based approaches using tunable laser sources. Post-launch calibration approaches for Pathfinder, EnMAP, CHIME, and DESIS including traditional vicarious calibration methods and the challenges of working with commercial data are presented. The vicarious calibration discussion relies on the example of the recently-available RadCalNet data to describe typical methods and challenges that will be faced when harmonising data between imaging spectrometers as well as with multispectral sensors
Cooling and recombination processes in cometary plasma
The ion electron plasma in comets is examined for cooling processes which result from its interactions with the neutral coma. A cometary coma model is formulated that is composed predominantly of H2O and its decomposition products where electrons are cooled in a variety of processes at rates varying with energy. It is shown that solar plasma plus accumulated cometary ions and electrons is affected very strongly as it flows into the coma. The electrons are rapidly cooled and all but some 10% of the ions undergo charge exchange. Photodissociation of H2O is assumed where ion electron recombination is the dominant loss process
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The Veterans Affairs Neuropathy Scale: A Reliable, Remote Polyneuropathy Exam.
Introduction: Polyneuropathy (PN) complaints are common, prompting many referrals for neurologic evaluation. To improve access of PN care in distant community clinics, we developed a telemedicine service (patient-clinician interactions using real-time videoconference technology) for PN. The primary goal of this study was to construct a remote exam for PN that is feasible, reliable, and concordant with in-person assessments for use in our tele-PN clinics. Methods: To construct the VA Neuropathy Scale (VANS), we searched the literature for existing, validated PN assessments. From these assessments, we selected a parsimonious set of exam elements based on literature-reported sensitivity and specificity of PN detection, with modifications as necessary for our teleneurology setting (i.e., a technician examination under the direction of a neurologist). We recruited 28 participants with varying degrees of PN to undergo VANS testing under 5 scenarios. The 5 scenarios differed by mode of VANS grading (in-person vs. telemedicine) and by the in-person examiner type (neurologist vs. technician) in telemedicine scenarios. We analyzed concordance between the VANS and a person's medical chart-derived PN status by modeling the receiver operating characteristic (ROC) curve. We analyzed reliability of the VANS by mixed effects regression and computing the intraclass correlation coefficient (ICC) of scores across the 5 scenarios. Results: The VA Neuropathy Scale (VANS) tests balance, gait, reflexes, foot inspection, vibration, and pinprick. Possible scores range from 0 to 50 (worst). From the ROC curve, a cutoff of >2 points on the VANS sets the sensitivity and specificity of detecting PN at 98 and 91%, respectively. There is a small (1.3 points) but statistically significant difference in VANS scoring between in-person and telemedicine grading scenarios. For telemedicine grading scenarios, there is no difference in VANS scores between neurologist and technician examinations. The ICC is 0.89 across all scenarios. Discussion: The VANS, informed by existing PN instruments, is a promising clinical assessment tool for diagnosing and monitoring the severity of PN in telemedicine settings. This pilot study indicates acceptable concordance and reliability of the VANS with in-person examinations
A 3-D Multilateration: A Precision Geodetic Measurement System
A system was designed with the capability of determining 1-cm accuracy station positions in three dimensions using pulsed laser earth satellite tracking stations coupled with strictly geometric data reduction. With this high accuracy, several crucial geodetic applications become possible, including earthquake hazards assessment, precision surveying, plate tectonics, and orbital determination
Field-Tuning of the electron and hole populations in the ruthenate Bi_3Ru_3O_11
Experiments on the Hall coefficient R_H and heat capactity C reveal an
unusual, compensated electronic ground state in the ruthenate Bi_3Ru_3O_11. At
low temperature T, R_H decreases linearly with magnetic field |H| for fields
larger than the field scale set by the Zeeman energy. The results suggest that
the electron and hole populations are tuned by H in opposite directions via
coupling of the spins to the field. As T is decreased below 5 K, the curve
C(T)/T vs. T^2 shows an anomalous flattening consistent with a rapidly growing
Sommerfeld parameter \gamma(T). We discuss shifts of the electron and hole
chemical potentials by H to interpret the observed behavior of R_H.Comment: 5 pages, 6 figures, reference adde
Pemahaman Tabib Etnis Tionghoa di Surabaya Mengenai Yīnyáng 泗水中医对阴阳之理解
Artikel ini bertujuan untuk mengetahui pemahaman tabib etnis Tionghoa di Surabaya mengenai yīnyáng dan cara penerapan konsep yīnyáng dalam profesi mereka.Teori yang menunjang terdiri atas teori keseimbangan yīnyáng merupakan dasar vitalitas kehidupan; keterkaitan konsep yīnyáng dengan keseimbangan bekerja, istirahat, dan bergerak. Artikel ini menggunakan metode penelitian kualitatif deskriptif dan teknik pengumpulan data dilakukan dengan cara wawancara semi terstruktur kepada masyarakat etnis Tionghoa Surabaya yang berprofesi sebagai tabib. Dari hasil penelitian diketahui bahwa para responden semuanya mengetahui konsep yīnyáng, sehingga semua responden menerapkan konsep keseimbangan yīnyáng dalam profesi mereka masing-masing
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Teleneurology clinics for polyneuropathy: a pilot study.
INTRODUCTION:Polyneuropathy (PN) is a common condition with significant morbidity. We developed tele-polyneuropathy (tele-PN) clinics to improve access to neurology and increase guideline-concordant PN care. This article describes the mixed-methods evaluation of pilot tele-PN clinics at three community sites within the Greater Los Angeles VA Healthcare System. METHODS:For the first 25 patients (48 scheduled visits), we recorded the duration of the tele-PN visit and exam; the performance on three guideline-concordant care indicators (PN screening labs, opiate reduction, physical therapy for falls); and patient-satisfaction scores. We elicited comments about the tele-PN clinic from patients and the clinical team. We combined descriptive statistics with qualitative themes to determine the feasibility and acceptability of the tele-PN clinics. RESULTS:The average tele-PN encounter and exam times were 28.5 and 9.1 min, respectively. PN screening lab completion increased from 80 to 100%. Opiate freedom improved from 68 to 88%. Physical therapy for patients with recent falls increased from 58 to 100%. The tele-PN clinic was preferred for follow-up over in-person clinics in 86% of cases. Convenience was paramount to the clinic's success, saving an average of 231 min per patient in round-trip travel. The medical team's caring and collaborative spirit received high praise. While the clinic's efficiency was equal or superior to in-person care, the limited treatment options for PN and the small clinical exam space are areas for improvement. CONCLUSION:In this pilot, we were able to efficiently see and examine patients remotely, promote guideline-concordant PN care, and provide a high-satisfaction encounter
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