Search results for "Correlation coefficient"
showing 10 items of 166 documents
Ratio of UV to global broad band irradiation in Valencia, Spain
1999
This paper presents the results of an analysis of 6 years of measurements of UV and broad band irradiation values in Valencia, Spain. Hourly and daily integrated UV irradiance, ITUV, measured by a TUVR Eppley radiometer, and global irradiance IT from a Kipp-Zonen CM-11 pyranometer, were highly correlated, with ITUV/IT percentages varying from 2.9% to 3.5% for hourly values and from 2.9% to 3.4% for daily values. If a general linear relation ITUV=mIT is considered, the correlation coefficient r is always greater than 0.96 for hourly values and 0.91 for daily values. However, the relation between ITUV/IT and the clearness index kT is poorly correlated, although improved results, with less dep…
Two-days ahead prediction of daily maximum concentrations of SO2, O3, PM10, NO2, CO in the urban area of Palermo, Italy
2007
Abstract Artificial neural networks are functional alternative techniques in modelling the intricate vehicular exhaust emission dispersion phenomenon. Pollutant predictions are notoriously complex when using either deterministic or stochastic models, which explains why this model was developed using a neural network. Neural networks have the ability to learn about non-linear relationships between the used variables. In this paper a recurrent neural network (Elman model) based forecaster for the prediction of daily maximum concentrations of SO2, O3, PM10, NO2, CO in the city of Palermo is proposed. The effectiveness of the presented forecaster was tested using a time series recorded between …
The erythemal clearness index for Valencia, Spain
2009
The values of three clearness indices have been measured for the city of Valencia: kt, the clearness index for the whole solar spectrum, ktUV the clearness index for the ultraviolet range, and the erythemal clearness index for the erythemal radiation ktUVER, corresponding to the solar radiation weighted by the erythemal action spectrum on human skin, normalized with respect to the solar constant corresponding to that spectrum. The measurements of ktUV reached values that were approximately 54% of that corresponding to kt, while those of ktUVER were much smaller. Some statistics of the erythemal clearness index have been calculated both for monthly as well as hourly means. The shape of the d…
A statistical model for predicting the inter-annual variability of birch pollen abundance in Northern and North-Eastern Europe
2018
The paper suggests a methodology for predicting next-year seasonal pollen index (SPI, a sum of daily-mean pollen concentrations) over large regions and demonstrates its performance for birch in Northern and North-Eastern Europe. A statistical model is constructed using meteorological, geophysical and biological characteristics of the previous year). A cluster analysis of multi-annual data of European Aeroallergen Network (EAN) revealed several large regions in Europe, where the observed SPI exhibits similar patterns of the multi-annual variability. We built the model for the northern cluster of stations, which covers Finland, Sweden, Baltic States, part of Belarus, and, probably, Russia and…
Interannual Variability of Biomass (SMOS Vegetation Optical Depth) Over the Contiguous United States
2021
Interannual variability in biomass represented by SMOS vegetation optical depth (VOD) and precipitation was assessed over the Contiguous United States. The greatest interannual variability in both VOD and precipitation occurred in shrubs and herbaceous (grasslands), with forests the least variable. At a continental scale, VOD was strongly correlated with annual precipitation. Results showed a significant correlation coefficient (∼ 0.93) between interannual variability of precipitation and biomass, indicating that the interannual variability of precipitation could be a good predictor of the interannual variability of biomass.
Comparison between rectal and body surface temperature in dogs by the calibrated infrared thermometer
2020
Highlights • Dogs poorly tolerate rectal temperature measurements with a contact thermometer. • Existing alternative approaches used uncalibrated infrared thermometers. • Gum and inguinal temperature are correlated moderately to rectal temperature. • Hyperthermia was detected with sensitivity and specificity up to 90.0% and 78.6%. • Future studies should include a calibrated thermometer and control external factors.
Diagnostic efficacy of panoramic mandibular index to identify postmenopausal women with low bone mineral densities
2011
Objectives: The aim of the study was to compare and assess the accuracy of panoramic mandibular index (PMI) and antegonial index (AI) in the panoramic radiographs of postmenopausal women with normal and low skeletal bone mineral densities( BMD) diagnosed by using dual energy x-ray absorptiometry ( DXA). Study Design: In panoramic radiographs obtained from 40 post menopausal women( 20 normal and 20 osteoporo tic) aged between 50-75 who’s BMD has already been assessed by a DXA, the mean was calculated for PMI and AI index values measured in the right and left mandibles. The PMI and AI index values were evaluated using the student’s t test. The correlation between the observers for indices was…
Late Breaking Abstract - Validation of a tool for the assessment of disease awareness (DA) in COPD
2017
Background: DA could influence adherence to treatment and outcomes. No validated tools are available to assess DA in COPD Aims: To generate a tool able to explore DA in COPD patients, the Disease Awareness in COPD Questionnaire (DACQ) Methods: A 2-step Delphi approach was used to develop a questionnaire that was tested for validity in a cohort of COPD patients of an Italian observational, multicenter, prospective study (SAT study - NCT02689492) Results: Consensus on a 27-item provisional questionnaire was obtained with 2 Delphi rounds. Factor analysis showed a 4-factor solution accounting for 35% of variance; each factor (disease acceptance, awareness of treatment needs, disease knowledge, …
Three dimensional reliability analyses of currently used methods for assessment of sagittal jaw discrepancy
2018
Background The objective of this study was to analyse three dimensionally the reliability and correlation of angular and linear measurements in assessment of anteroposterior skeletal discrepancy. Material and Methods In this retrospective cross sectional study, a sample of 213 subjects were three-dimensionally analysed from cone-beam computed tomography scans. The sample was divided according to three dimensional measurement of anteroposterior relation (ANB angle) into three groups (skeletal Class I, Class II and Class III). The anterior-posterior cephalometric indicators were measured on volumetric images using Anatomage software (InVivo5.2). These measurements included three angular and s…
Validity and reliability of Veloflex to measure active cervical range of motion in asymptomatic and symptomatic subjects
2021
Background Neck pain has a high annual incidence and decreases the cervical active range of motion (ROM). Clinicians use various methods to evaluate cervical range of motion (CROM) that some of them have also been proposed to give instant feedback. Accordingly, this study aimed to examine the validity and reliability of Veloflex (VF) to measure the CROM by comparison with the cervical range of motion (CROM) device, and to examine their test-retest reliability. Methods Thirty-eight healthy and 20 symptomatic participants were evaluated. Cervical flexion-extension, side bending, and rotations were tested in two sessions, first by the CROM and VF and in the second only with the VF. To evaluat…