Carbon resistor gauges for measuring shock and detonation pressures. III. Revised calibration data and relationships

Rationale. Quantitative CT (QCT) bone densitometry with asynchronous calibration not require a phantom during the scan procedure. Based on calibration data it converts X-ray density in HU to bone mineral density (BMD). Given the large number of CT studies performed on patients at risk of osteoporosis, there is a need for a hands-on method capable of assessing BMD in a short period of time without tailored software or protocols.Goal. To develop a method for QCT bone densitometry using an PHK (PHantom Kalium), to compare the volume BMD measurements with the QCT data with asynchronous calibration provided by software from a reputable developer.Methods. The studies were performed at 64-slice CT unit with body scanning parameters. The BMD was measured using two techniques: 1) QCT with asynchronous calibration using software from a reputable developer; 2) QCT using a PHK phantom (QCT-PHK). For convert the HU to BMD values, we scanned the PHK phantom and calculate correction factor. Phantom contains “vertebrae” filled with potassium hydrogen phosphate in different concentrations. In both methods, the BMD values measured for LI–II, and sometimes for ThXII, LIII.Results. The study enrolled 65 subjects (11 male and 54 female patients); median age 69.0 years. A comparison of the vertebrae BMD measured by QCT and QCT-PHK revealed a significant linear Pearson correlation r = 0.977 (p < 0.05). The Bland–Altman analysis demonstrated a lack of relationship between the difference in measurements and the average BMD and a systematic BMD; bias of +4.50 mg/ml in QCT vs. QCT-PHK. Differences in the division into groups osteoporosis / osteopenia / norm according to the ACR criteria for the two methods were not significant.Conclusion. The developed asynchronous QCT-PHK method measure BMD comparable to the widely used QCT with asynchronous calibration. This method can be used for opportunistic screening for osteoporosis.

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Preliminary uncertainty analysis – a prerequisite for assessing the predictive uncertainty of hydrologic models

Water Science & Technology ◽

10.2166/wst.1996.0039 ◽

1996 ◽

Vol 33 (2) ◽

pp. 79-90 ◽

Cited By ~ 6

Author(s):

Jian Hua Lei ◽

Wolfgang Schilling

Keyword(s):

Uncertainty Analysis ◽

Model Parameters ◽

Observation Data ◽

Calibration Data ◽

Model Output ◽

Predictive Uncertainty ◽

Runoff Volume ◽

Output Uncertainty ◽

Sensitive Parameters ◽

Calculated Model

Physically-based urban rainfall-runoff models are mostly applied without parameter calibration. Given some preliminary estimates of the uncertainty of the model parameters the associated model output uncertainty can be calculated. Monte-Carlo simulation followed by multi-linear regression is used for this analysis. The calculated model output uncertainty can be compared to the uncertainty estimated by comparing model output and observed data. Based on this comparison systematic or spurious errors can be detected in the observation data, the validity of the model structure can be confirmed, and the most sensitive parameters can be identified. If the calculated model output uncertainty is unacceptably large the most sensitive parameters should be calibrated to reduce the uncertainty. Observation data for which systematic and/or spurious errors have been detected should be discarded from the calibration data. This procedure is referred to as preliminary uncertainty analysis; it is illustrated with an example. The HYSTEM program is applied to predict the runoff volume from an experimental catchment with a total area of 68 ha and an impervious area of 20 ha. Based on the preliminary uncertainty analysis, for 7 of 10 events the measured runoff volume is within the calculated uncertainty range, i.e. less than or equal to the calculated model predictive uncertainty. The remaining 3 events include most likely systematic or spurious errors in the observation data (either in the rainfall or the runoff measurements). These events are then discarded from further analysis. After calibrating the model the predictive uncertainty of the model is estimated.

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Prediction of signs/symptoms of decompression sickness following submarine tower escape

Undersea and Hyperbaric Medicine ◽

10.22462/01.03.2019.3 ◽

2019 ◽

pp. 17-33

Author(s):

Joel Edney ◽

Geoffrey Loveman ◽

Fiona Seddon ◽

Julian Thacker ◽

Karen Jurd ◽

...

Keyword(s):

Body Mass ◽

Marked Effect ◽

Decompression Sickness ◽

Outcome Data ◽

Calibration Data ◽

Limb Pain ◽

Pulmonary Barotrauma ◽

Escape Depth ◽

Different Types ◽

Risk Curves

Crew survival in a distressed submarine (DISSUB) scenario may be enhanced by the knowledge of the risks of different types of decompression sickness (DCS) should the crew attempt tower escape. Four models were generated through calibration against DCS outcome data from 3,919 pressure exposures, each for the prediction of one of four categories of DCS: neurological, limb pain, respiratory and cutaneous. The calibration data contained details of human, goat, sheep and pig exposures to raised pressure while breathing air or oxygen/nitrogen mixtures. No exposures had substantial staged decompression or cases of suspected pulmonary barotrauma. DCS risk was scaled between species and with body mass. A parameter was introduced to account for the possibility of the occurrence of some symptom types masking others. The calibrated models were used to estimate likelihood of DCS occurrence for each symptom category following submarine tower escape. Escape depth was found to have a marked effect only on predicted rates of neurological DCS. Saturation at raised internal DISSUB pressure prior to escape was found to affect predicted rates of all symptom types. The iso-risk curves presented are offered as guidance to submarine crews and rescue forces in preparation for, or in the event of, a DISSUB scenario.

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InSAR Multitemporal Data over Persistent Scatterers to Detect Floodwater in Urban Areas: A Case Study in Beletweyne, Somalia

Remote Sensing ◽

10.3390/rs13010037 ◽

2020 ◽

Vol 13 (1) ◽

pp. 37

Author(s):

Luca Pulvirenti ◽

Marco Chini ◽

Nazzareno Pierdicca

Keyword(s):

Urban Area ◽

Urban Areas ◽

The Other ◽

Spatial Average ◽

Calibration Data ◽

Suburban Areas ◽

Persistent Scatterers ◽

Optical Images ◽

Interferometric Phase ◽

Multitemporal Data

A stack of Sentinel-1 InSAR data in an urban area where flood events recurrently occur, namely Beletweyne town in Somalia, has been analyzed. From this analysis, a novel method to deal with the problem of flood mapping in urban areas has been derived. The approach assumes the availability of a map of persistent scatterers (PSs) inside the urban settlement and is based on the analysis of the temporal trend of the InSAR coherence and the spatial average of the exponential of the InSAR phase in each PS. Both interferometric products are expected to have high and stable values in the PSs; therefore, anomalous decreases may indicate that floodwater is present in an urban area. The stack of Sentinel-1 data has been divided into two subsets. The first one has been used as a calibration set to identify the PSs and determine, for each PS, reference values of the coherence and the spatial average of the exponential of the interferometric phase under standard non-flooded conditions. The other subset has been used for validation purposes. Flood maps produced by UNOSAT, analyzing very-high-resolution optical images of the floods that occurred in Beletweyne in April–May 2018, October–November 2019, and April–May 2020, have been used as reference data. In particular, the map of the April–May 2018 flood has been used for training purposes together with the subset of Sentinel-1 calibration data, whilst the other two maps have been used to validate the products generated by applying the proposed method. The main product is a binary map of flooded PSs that complements the floodwater map of rural/suburban areas produced by applying a well-consolidated algorithm based on intensity data. In addition, a flood severity map that labels the different districts of Beletweyne, as not, partially, or totally flooded has been generated to consolidate the validation. The results have confirmed the effectiveness of the proposed method.

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In vivo calibration of the T2* cardiovascular magnetic resonance method at 1.5 T for estimation of cardiac iron in a minipig model of transfusional iron overload

Journal of Cardiovascular Magnetic Resonance ◽

10.1186/s12968-021-00715-6 ◽

2021 ◽

Vol 23 (1) ◽

Author(s):

Peter Diedrich Jensen ◽

Asbjørn Haaning Nielsen ◽

Carsten Wiberg Simonsen ◽

Ulrik Thorngren Baandrup ◽

Svend Eggert Jensen ◽

...

Keyword(s):

Rank Correlation ◽

Calibration Data ◽

Iron Loading ◽

Spearman Rank Correlation ◽

Calibration Equation ◽

Spearman Rank ◽

Cardiac Iron ◽

In Vivo Calibration ◽

Spearman Rank Correlation Coefficient

Abstract Background Non-invasive estimation of the cardiac iron concentration (CIC) by T2* cardiovascular magnetic resonance (CMR) has been validated repeatedly and is in widespread clinical use. However, calibration data are limited, and mostly from post-mortem studies. In the present study, we performed an in vivo calibration in a dextran-iron loaded minipig model. Methods R2* (= 1/T2*) was assessed in vivo by 1.5 T CMR in the cardiac septum. Chemical CIC was assessed by inductively coupled plasma-optical emission spectroscopy in endomyocardial catheter biopsies (EMBs) from cardiac septum taken during follow up of 11 minipigs on dextran-iron loading, and also in full-wall biopsies from cardiac septum, taken post-mortem in another 16 minipigs, after completed iron loading. Results A strong correlation could be demonstrated between chemical CIC in 55 EMBs and parallel cardiac T2* (Spearman rank correlation coefficient 0.72, P < 0.001). Regression analysis led to [CIC] = (R2* − 17.16)/41.12 for the calibration equation with CIC in mg/g dry weight and R2* in Hz. An even stronger correlation was found, when chemical CIC was measured by full-wall biopsies from cardiac septum, taken immediately after euthanasia, in connection with the last CMR session after finished iron loading (Spearman rank correlation coefficient 0.95 (P < 0.001). Regression analysis led to the calibration equation [CIC] = (R2* − 17.2)/31.8. Conclusions Calibration of cardiac T2* by EMBs is possible in the minipig model but is less accurate than by full-wall biopsies. Likely explanations are sampling error, variable content of non-iron containing tissue and smaller biopsies, when using catheter biopsies. The results further validate the CMR T2* technique for estimation of cardiac iron in conditions with iron overload and add to the limited calibration data published earlier.

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Cariaco Basin Calibration Update: Revisions to Calendar and 14C Chronologies for Core Pl07-58Pc

Radiocarbon ◽

10.1017/s0033822200033075 ◽

2004 ◽

Vol 46 (3) ◽

pp. 1161-1187 ◽

Cited By ~ 46

Author(s):

Konrad A Hughen ◽

John R Southon ◽

Chanda J H Bertrand ◽

Brian Frantz ◽

Paula Zermeño

Keyword(s):

Tree Ring ◽

Cariaco Basin ◽

Calibration Data ◽

Data Set ◽

Varve Chronology ◽

Pine Tree ◽

Tree Ring Data ◽

Calibration Data Set ◽

Recent Version ◽

Radiocarbon Calibration

This paper describes the methods used to develop the Cariaco Basin PL07-58PC marine radiocarbon calibration data set. Background measurements are provided for the period when Cariaco samples were run, as well as revisions leading to the most recent version of the floating varve chronology. The floating Cariaco chronology has been anchored to an updated and expanded Preboreal pine tree-ring data set, with better estimates of uncertainty in the wiggle-match. Pending any further changes to the dendrochronology, these results represent the final Cariaco 58PC calibration data set.

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Atomic physics and solar polarimetry

Canadian Journal of Physics ◽

10.1139/cjp-2016-0836 ◽

2017 ◽

Vol 95 (9) ◽

pp. 847-854 ◽

Cited By ~ 4

Author(s):

P.G. Judge

Keyword(s):

Adaptive Optics ◽

Atomic Physics ◽

Solar Physics ◽

Polarized Light ◽

Initial Study ◽

Spectral Lines ◽

Calibration Data ◽

Science Data ◽

On Line ◽

Singly Charged

Major outstanding problems in solar physics relate to solar magnetism. Spectropolarimetry offers the best, and sometimes only, method of obtaining accurate measurements of the Sun’s magnetic field. New 1.5–2 m class telescopes with adaptive optics have come on line, and the Daniel K. Inouye 4 m Solar Telescope (DKIST) will begin observing in 2019. The calibration of polarized light entering such a large and polarizing ground-based telescope represents difficult challenges. This paper explores how special polarization properties of particular atomic transitions may provide calibration data, augmenting or even avoiding time-consuming calibration observations, as well as science data. This initial study concludes that solar spectral lines exist with special polarization properties, allowing the telescope calibration to be determined. The Sun’s visible and infrared spectrum is dominated by lines of neutral atoms and singly charged ions of iron and other complex atoms. Both solar and atomic physics should jointly benefit from telescopic advances, as observers explore regimes of broader wavelength ranges, and higher spatial resolutions and polarimetric sensitivities, than they have reached in the past. Further work is in progress to identify particular transitions of practical use to aid in calibrations.

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