A New Cloud Screening Algorithm for Ground-Based Direct-Beam Solar Radiation

2014 ◽  
Vol 31 (12) ◽  
pp. 2591-2605 ◽  
Author(s):  
Maosi Chen ◽  
John Davis ◽  
Wei Gao
Keyword(s):  
Solar Radiation ◽  
Screening Method ◽  
Mean Value ◽  
Target Point ◽  
Department Of Agriculture ◽  
Direct Beam ◽  
Screening Algorithm ◽  
In Situ Calibration ◽  
Multifilter Rotating Shadowband Radiometer ◽  
Cloud Screening

Abstract Cloud screening of direct-beam solar radiation is an essential step for in situ calibration and atmospheric properties retrieval. The internal cloud screening module of a Langley analysis program [Langley Analyzer (LA)] used by the U.S. Department of Agriculture (USDA) UV-B Monitoring and Research Program (UVMRP) is used for screening the uncalibrated direct-beam measurements and for deriving Langley offset voltages for calibration of the UV version of the Multifilter Rotating Shadowband Radiometer (UV-MFRSR). The current LA cloud screening module utilizes data from extended clear-sky periods and tends to ignore shorter periods that typify periods of broken cloudiness, and as a result, fewer values are generated for sites with higher frequencies of cloudy days (cloudy sites). A new cloud screening algorithm is presented that calculates the total optical depth (TOD) difference between a target point and pairs of points, and identifies the target as cloudy if the mean TOD difference exceeds a certain threshold. The screening is an iterative process that finishes when no new cloudy points are found. The result at a typical clear/sunny site shows that values from partly cloudy days are consistent with those from cloud-free days, when the new method is employed. The new cloud screening algorithm picks up significantly more values at cloudy sites. The larger decrease of the annual mean value of at cloudy sites than at relatively clear sites suggests the potential for improving calibration accuracy at cloudy sites. The results also show that the new cloud screening method is capable of detecting clear points in short clear windows and in transitional regions.

Effect of season on thermoregulatory responses and energy expenditure of goats on semi-arid range in India

2002 ◽  
Vol 139 (1) ◽  
pp. 87-93 ◽  
Author(s):  
A. K. SHINDE ◽  
RAGHAVENDRA BHATTA ◽  
S. K. SANKHYAN ◽  
D. L. VERMA
Keyword(s):  
Heart Rate ◽  
Heat Stress ◽  
Solar Radiation ◽  
Energy Expenditure ◽  
Arid Regions ◽  
Physiological Responses ◽  
Face Mask ◽  
Mean Value ◽  
The Mean ◽  
Semi Arid

A study of the physiological responses and energy expenditure of goats was carried out from June 1999 to May 2000 by conducting two experiments: one on bucks maintained on stall feeding in autumn 1999 (Expt 1) followed by year-round grazing on native ranges over three seasons: monsoon, winter and summer (Expt 2). Physiological responses and energy expenditure (EE) measurements of housed and grazing goats were recorded at 06.00 h and 14.00 h for 5 consecutive days in each season. Goats were fixed with a face mask and meteorological balloon for collection of expired air and measurement of EE. Respiration rate (RR) at 06.00 h was similar in all seasons (14 respiration/min) except in the monsoon, where a significantly (P<0.05) higher value (26 respiration/min) was recorded. At 14.00 h, RR was higher in monsoon and summer (81 and 91 respiration/min) than in winter (52 respiration/min). Irrespective of the season, heart rate (HR) was higher at 14.00 h (86 beat/min) than at 06.00 h (64 beat/min). The rise of rectal temperature (RT) from morning (06.00 h) to peak daily temperature (14.00 h) was 0.9 °C in housed goats in autumn and 1.0, 2.1 and 2.0 °C in grazing goats during monsoon, winter and summer, respectively. The mean value was 1.7 °C. Skin temperature (ST) was lowest in winter (30.1 °C) and highest at 14.00 h in summer (40.3 °C). Energy expenditure of goats at 06.00 h was 32.7 W in winter and significantly (P<0.05) increased to 52.0 W in summer and 107.8 W in monsoon. At 14.00 h, EE was 140.2 W in winter and increased to 389.0 W and 391.3 W respectively in monsoon and summer. It is concluded that monsoon and summer are both stressful seasons in semi-arid regions. Animals should be protected from direct solar radiation during the hottest hours of the day to ameliorate the effect of heat stress.

Cloud-Screening Algorithm for ENVISAT/MERIS Multispectral Images

2007 ◽  
Vol 45 (12) ◽  
pp. 4105-4118 ◽  
Author(s):  
L. Gomez-Chova ◽  
G. Camps-Valls ◽  
J. Calpe-Maravilla ◽  
L. Guanter ◽  
J. Moreno
Keyword(s):  
Multispectral Images ◽  
Screening Algorithm ◽  
Cloud Screening

scholarly journals Sensitivity of hemodynamic parameters obtained by conventional duplex scanner in the evaluation of extracranial carotid disease severity

2003 ◽  
Vol 60 (4) ◽  
pp. 435-442
Author(s):  
Gordana Arandjelovic-Minic
Keyword(s):  
Spectral Analysis ◽  
Carotid Stenosis ◽  
Doppler Ultrasonography ◽  
Screening Method ◽  
Statistical Processing ◽  
Mean Value ◽  
Hemodynamic Parameter ◽  
Hemodynamic Parameters ◽  
Carotid Disease ◽  
Significant Independent Predictor

Progresson of extracranial carotid disease is considered to be significant independent predictor in the evaluation of individual cerebrovascular prognosis. Doppler ultrasonography is a useful screening method in the diagnosis and evaluation of extracranial carotid disease. The aim of this study was to establish the most sensitive hemodynamic parameter of Doppler-ultrasonographic spectral analysis in clinical evaluation of extracranial carotid disease. Investigation included 90 patients (of both sexes) in hospital and outpatient clinic care. Spectral analysis (M-scanning technique) was used for the evaluation of hemodynamic status of carotid sinus, including the following parameters: Pourcelot (A-D/A), Gosling (A/B) and Mol (A/D) resistance parameters. After statistical processing the results of the research affirmed hemodynamic parameters' values and correlation between Pourcelot hemodynamic parameter and the degree of carotid stenosis ?=0,59 for all patients, and ?=0,58 for patients with pathological values. Correlation between Mol parameter and the degree of carotid stenosis was ?=0,50 for all patients, and ?=0,57 for patients with pathological values. Gosling parameter was not significantly different in mean value and was present in all three groups. Functional relationship between the degree of carotid stenosis and each of hemodynamic parameters was established. It was concluded that Pourcelot and Mol parameters were significant indicators of asimptomatic carotid disease, but Pourcelot parameter was considered as a more sensitive indicator in the evaluation of extracranial carotid disease.

scholarly journals Accuracy and Incremental Yield of the Chest X-Ray in Screening for Tuberculosis in Uganda: A Cross-Sectional Study

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Joanitah Nalunjogi ◽  
Frank Mugabe ◽  
Irene Najjingo ◽  
Pastan Lusiba ◽  
Francis Olweny ◽  
...  
Keyword(s):  
Screening Tool ◽  
Screening Method ◽  
Cross Sectional Study ◽  
Case Detection ◽  
Sectional Study ◽  
Cross Sectional ◽  
X Ray ◽  
Number Needed To Screen ◽  
Screening Algorithm ◽  
Chest X Ray

The WHO END TB strategy requires ≥90% case detection to combat tuberculosis (TB). Increased TB case detection requires a more sensitive and specific screening tool. Currently, the symptoms recommended for screening TB have been found to be suboptimal since up to 44% of individuals with TB are asymptomatic. The chest X-ray (CXR) as a screening tool for pulmonary TB was evaluated in this study, as well as its incremental yield in TB diagnosis using a cross-sectional study involving secondary analysis of data of 4512 consented/assented participants ≥15 years who participated in the Uganda National TB prevalence survey between 2014 and 2015. Participants with a cough ≥2 weeks, fever, weight loss, and night sweats screened positive for TB using the symptoms screening method, while participants with a TB defining abnormality on CXR screened positive for TB by the CXR screening method. The Löwenstein-Jensen (LJ) culture was used as a gold standard for TB diagnosis. The CXR had 93% sensitivity and 65% specificity compared to LJ culture results, while symptoms had 76% sensitivity and 31% specificity. The screening algorithm involving the CXR in addition to symptoms led to a 38% increment in the yield of diagnosed tuberculosis. The number needed to screen using the CXR and symptoms screening algorithm was 32 compared to 45 when the symptoms are used alone. Therefore, the CXR in combination with symptoms is a good TB screening tool and increases the yield of diagnosed TB.

scholarly journals Compatibility of different measurement techniques. Long-term global solar radiation observations at Izaña Observatory

2016 ◽  
Author(s):  
Rosa Delia García ◽  
Emilio Cuevas ◽  
Omaira Elena García ◽  
Ramon Ramón ◽  
Pedro Miguel Romero-Campos ◽  
...  
Keyword(s):  
Time Series ◽  
Solar Radiation ◽  
Sunshine Duration ◽  
Measurement Techniques ◽  
Temporal Stability ◽  
Global Solar Radiation ◽  
Surface Radiation ◽  
Multifilter Rotating Shadowband Radiometer ◽  
High Consistency

Abstract. A 1-year intercomparison of classical and modern radiation and sunshine duration instruments has been performed at Izaña Atmospheric Observatory (IZO) located in Tenerife (Canary Islands, Spain) starting on July 17, 2014. We compare global solar radiation (GSR) records measured with a CM-21 pyranometer Kipp &amp; Zonen, taken in the framework of the Baseline Surface Radiation Network, with those measured with a Multifilter Rotating Shadowband Radiometer (MFRSR), and a bimetallic pyranometer (PYR), and GSR estimated from sunshine duration performed by a Campbell-Stokes sunshine recorder (CS) and a Kipp &amp; Zonen sunshine duration sensor (CSD). Given the GSR BSRN records are subject of strict quality controls (based on principles of physical limits and comparison with the LibRadtran model), they have been used as reference in the intercomparison study. We obtain an overall root mean square error (RMSE) of ~0.9 MJm2 (4 %) for GSR PYR and GSR MFRSR, 1.9 MJm2 (7 %) and 1.2 MJm2 (5 %) for GSR CS and GSR CSD, respectively. Factors such as temperature, fraction of the clear sky, relative humidity and the solar zenith angle have shown to moderately affect the GSR observations. As application of the methodology developed in this work, we have re-evaluated the GSR time series between 1977 and 1991 obtained with two PYRs at IZO. By comparing with coincident GSR estimates from SD observations, we probe the high consistency of those measurements and their temporal stability. These results demonstrate that 1) the continuous-basis intercomparison of different GSR techniques offers important diagnostics for identifying inconsistencies between GSR data records, and 2) the GSR measurements performed with classical and more simple instruments are consistent with more modern techniques and, thus, valid to recover GSR time series and complete worldwide distributed GSR data. The intercomparison and quality assessment of these different techniques have allowed to obtain a complete and consistent long-term global solar radiation series (1977–2015) at Izaña.

scholarly journals Cloud screening in AVHRR digital data over Arctic regions

1993 ◽  
Vol 17 ◽  
pp. 386-390 ◽  
Author(s):  
Sonia C. Gallegos ◽  
Jeffrey D. Hawkins ◽  
Chiu Fu Cheng
Keyword(s):  
Single Channel ◽  
Screening Method ◽  
Detection Algorithm ◽  
Digital Data ◽  
Cloud Detection ◽  
Arctic Regions ◽  
Identification Technique ◽  
Multiple Band ◽  
Cloud Screening ◽  
Very High

A cloud screening method initially generated to mask cloud contaminated pixels over the ocean in visible/infrared imagery, has been revised and adapted to detect clouds over Arctic regions with encouraging results. Although the method is quite successful in eliminating very cold clouds, it underestimates low level clouds. However, this does not appear to interfere with monitoring of ice related features such as leads or the ice edge in Advanced Very High Resolution Radiometer (AVHRR) scenes. The method uses: a multiple-band approach to produce signatures not readily available in single channel data, an edge detection/dilation technique to locate features in the clouds and to join isolated edges, and a polygon identification technique to remove noise in the form of isolated pixels and separate clear regions from cloud contaminated areas. The method has been tested over a limited set of data with consistent results. Initial evaluation of the usefulness of this cloud-detection algorithm in data-fusion experiments indicate a potential in locating areas in AVHRR data which are cloud contaminated and which could yield a far superior representation of the ice features if replaced with data from a different sensor such as the Special Sensor Microwave/lmager (SSM/I).

Development of a cloud-screening algorithm for direct and diffuse AODs from the Skyradiometer Network

2020 ◽  
Vol 243 ◽  
pp. 104997
Author(s):  
Yongjoo Choi ◽  
Young Sung Ghim ◽  
Sang-Woo Kim ◽  
Huidong Yeo
Keyword(s):  
Screening Algorithm ◽  
Cloud Screening

Endoscopic approach to colloid cyst: what is the optimal entry point and trajectory?

2014 ◽  
Vol 121 (4) ◽  
pp. 790-796 ◽  
Author(s):  
Leonardo Rangel-Castilla ◽  
Fangxiang Chen ◽  
Lawrence Choi ◽  
Justin C. Clark ◽  
Peter Nakaji
Keyword(s):  
Colloid Cyst ◽  
Mean Value ◽  
Entry Point ◽  
Preoperative Imaging ◽  
Target Point ◽  
Coronal Suture ◽  
Anatomical Structures ◽  
Entry Points ◽  
Stereotactic Navigation ◽  
Neurovascular Structures

Object An optimal entry point and trajectory for endoscopic colloid cyst (ECC) resection helps to protect important neurovascular structures. There is a large discrepancy in the entry point and trajectory in the neuroendoscopic literature. Methods Trajectory views from MRI or CT scans used for cranial image guidance in 39 patients who had undergone ECC resection between July 2004 and July 2010 were retrospectively evaluated. A target point of the colloid cyst was extended out to the scalp through a trajectory carefully observed in a 3D model to ensure that important anatomical structures were not violated. The relation of the entry point to the midline and coronal sutures was established. Entry point and trajectory were correlated with the ventricular size. Results The optimal entry point was situated 42.3 ± 11.7 mm away from the sagittal suture, ranging from 19.1 to 66.9 mm (median 41.4 mm) and 46.9 ± 5.7 mm anterior to the coronal suture, ranging from 36.4 to 60.5 mm (median 45.9 mm). The distance from the entry point to the target on the colloid cyst varied from 56.5 to 78.0 mm, with a mean value of 67.9 ± 4.8 mm (median 68.5 mm). Approximately 90% of the optimal entry points are located 40–60 mm in front of the coronal suture, whereas their perpendicular distance from the midline ranges from 19.1 to 66.9 mm. The location of the “ideal” entry points changes laterally from the midline as the ventricles change in size. Conclusions The results suggest that the optimal entry for ECC excision be located at 42.3 ± 11.7 mm perpendicular to the midline, and 46.9 ± 5.7 mm anterior to the coronal suture, but also that this point differs with the size of the ventricles. Intraoperative stereotactic navigation should be considered for all ECC procedures whenever it is available. The entry point should be estimated from the patient's own preoperative imaging studies if intraoperative neuronavigation is not available. An estimated entry point of 4 cm perpendicular to the midline and 4.5 cm anterior to the coronal suture is an acceptable alternative that can be used in patients with ventriculomegaly.

Variability and habituation of nystagmic responses to hot caloric stimulation of normal subjects

1982 ◽  
Vol 96 (7) ◽  
pp. 599-612 ◽  
Author(s):  
P. G. Davey ◽  
E. S. Harpur ◽  
F. Jabeen ◽  
D. Shannon ◽  
P. M. Shenoi
Keyword(s):  
Phase Velocity ◽  
Screening Method ◽  
Normal Subjects ◽  
Mean Value ◽  
Slow Phase ◽  
Caloric Test ◽  
Maximum Frequency ◽  
Slow Phase Velocity ◽  
Caloric Stimulation ◽  
Vestibular Toxicity

AbstractExperiments were performed on 25 otoneurologically ‘normal’ subjects to evaluate the hot caloric test as a screening test for aminoglycoside vestibular toxicity.Using portable equipment under non-ideal conditions, it was found that there was a large inter-subject variability in nystagmic response and that, instead of a random test-retest variability, a systagmic variation in response occurred on repeated caloric stimulation with water at 44°C.A response deline (habituation) evident in both the maximum slow phase velocity and the maximum frequency occurred at second test, although the inter-test interval ranged from 24 to 72 hours.After a 3-month interval with no intervening tests, the mean value of the maximum frequency reverted back to the original level. However, there was still a significant reduction in maximum slow phase velocity at this time. Some individuals had a sustanined reduction in both parameters.Hence it is concluded that the hot caloric test, used under the conditions described in this study, is not a suitable serial screening method for aminoglycoside vestibular toxicity. The reproducibility of this test under other conditions, or any other caloric test, should be established in normal subjects befre employing, it as a serial screen for aminoglycoside vestibular toxicity.

Comparison of Assurance GDS® MPX ID for Top STEC with Reference Culture Methods for the Detection of E. coli Top 6 STEC; Direct Confirmation of Top 6 STEC from Isolation Plates and Determination of Equivalence of PickPen® and FSIS OctoMACS™ Concentration Protocols

2016 ◽  
Vol 99 (2) ◽  
pp. 428-443 ◽  
Author(s):  
Philip Feldsine ◽  
Andrew H Lienau ◽  
Khyati Shah ◽  
Amy Immermann ◽  
Khanh Soliven ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laboratory Study ◽  
Screening Method ◽  
Ground Beef ◽  
Immunomagnetic Separation ◽  
Culture Methods ◽  
Department Of Agriculture ◽  
Independent Laboratory ◽  
Environmental Surfaces ◽  
Microbiological Methods

Abstract Assurance GDS® MPX ID for Top Shiga toxin-producing Escherichia coli (STEC; MPX ID) was validated according to the AOAC INTERNATIONAL Methods Committee Guidelines for Validation of Microbiological Methods for Foods and Environmental Surfaces as (1) a secondary screening method for specific detection of the Top 6 STEC serogroups (O26, O45, O103, O111, O121, and O145) in raw beef trim, raw ground beef, raw spinach, and on stainless steel; and (2) as a confirmatory method for the identification of pure culture isolates as Top 6 STEC. MPX ID is used in conjunction with the upfront BCS Assurance GDS MPX Top 7 STEC assay. This Performance Tested MethodSM validation has two main parts: Method Developer studies and the Independent Laboratory study. A total of 180 samples and controls were analyzed. Results showed that MPX ID had no statistically significant differences with the reference culture methods for the detection of Top 6 STEC in the food matrixes (raw beef trim, raw ground beef, and raw spinach) and environmental sponges (stainless steel) studied. Inclusivity/exclusivity studies were also conducted. One hundred percent inclusivity among the 50 Top 6 STEC serovars tested and 100% exclusivity for the 30 non-Top 6 STEC organisms tested were demonstrated. For validation of MPX ID as a confirmatory method for isolated colonies, all inclusivity and exclusivity organisms were streaked for isolation onto five STEC plating media: modified rainbow agar, Levine's eosin-methylene blue (L-EMB) agar, rainbow agar with novobiocin and cefixime, and enterohemolysin agar with selective agents as well as trypticase soy agar with yeast extract. These isolated colonies were suspended and analyzed by Assurance GDS MPX Top 7 STEC and MPX ID. MPX ID was able to correctly confirm all inclusivity organisms from all plate types, except two STEC isolates from L-EMB agar plates only in the Independent Laboratory study. All exclusivity organisms were correctly determined by MPX ID as non-Top 6 STEC from the STEC plating media. An additional but separate part of these studies was a comparison of immunomagnetic separation (IMS) efficiency using the Assurance GDS procedure with a PickPen® device and the U.S. Department of Agriculture procedure using the OctoMACS™ Separator device for plating onto chromogenic agar. Results demonstrated the equivalence of the two IMS procedures for plate confirmation of Top 7 STEC.

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