Journal articles: 'RV coefficient'

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Josse, J., J. Pagès, and F. Husson. "Testing the significance of the RV coefficient." Computational Statistics & Data Analysis 53, no. 1 (September 2008): 82–91. http://dx.doi.org/10.1016/j.csda.2008.06.012.

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Klok, Frederikus A., Noortje van der Bijl, Albert de Roos, Lucia J. M. Kroft, Menno V. Huisman, and Sharif M. Pasha. "NT-pro-BNP levels in patients with acute pulmonary embolism are correlated to right but not left ventricular volume and function." Thrombosis and Haemostasis 108, no. 08 (2012): 367–72. http://dx.doi.org/10.1160/th11-12-0901.

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SummaryN-terminal pro-Brain Natriuretic Peptide (NT-pro-BNP) is primarily secreted by left ventricular (LV) stretch and wall tension. Notably, NT-pro-BNP is a prognostic marker in acute pulmonary embolism (PE), which primarily stresses the right ventricle (RV). We sought to evaluate the relative contribution of the RV to NT-pro-BNP levels during PE. A posthoc analysis of an observational prospective outcome study in 113 consecutive patients with computed tomography (CT)-proven PE and 226 patients in whom PE was clinically suspected but ruled out by CT. In all patients RV and LV function was established by assessing ECG-triggered-CT measured ventricular end-diastolic-volumes and ejection fraction (EF). NT-pro-BNP was assessed in all patients. The correlation between RV and LV end-diastolic-volumes and systolic function was evaluated by multiple linear regression corrected for known con-founders. In the PE cohort increased RVEF (β-coefficient (95% confidence interval [CI]) –0.044 (± –0.011); p<0.001) and higher RV enddiastolic-volume (β-coefficient 0.005 (± 0.001); p<0.001) were significantly correlated to NT-pro-BNP, while no correlation was found with LVEF ( β-coefficient 0.005 (± 0.010); p=0.587) and LV end-diastolic-volume (β-coefficient –0.003 (± 0.002); p=0.074). In control patients without PE we found a strong correlation between NT-pro-BNP levels and LVEF ( β-coefficient –0.027 (± –0.006); p<0.001) although not LV enddiastolic-volume (β-coefficient 0.001 (± 0.001); p=0.418). RVEF (β-co-efficient –0.002 (± –0.006); p=0.802) and RV end-diastolic-volume (β-coefficient <0.001 (± 0.001); p=0.730) were not correlated in patients without PE. In PE patients, lower RVEF and higher RV end-diastolic-volume were significantly correlated to NT-pro-BNP levels as compared to control patients without PE. These observations provide patho-physiological ground for the well-known prognostic value of NT-pro-BNP in acute PE.

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Smilde, A. K., H. A. L. Kiers, S. Bijlsma, C. M. Rubingh, and M. J. van Erk. "Matrix correlations for high-dimensional data: the modified RV-coefficient." Bioinformatics 25, no. 3 (December 10, 2008): 401–5. http://dx.doi.org/10.1093/bioinformatics/btn634.

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Rauf Ahmad, M. "A significance test of the RV coefficient in high dimensions." Computational Statistics & Data Analysis 131 (March 2019): 116–30. http://dx.doi.org/10.1016/j.csda.2018.10.008.

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Draheim, Christopher C., Bruce L. Bakke, Robert C. Serfass, Paul V. Snyder, and Ava J. Walker. "Underwater Weighing Familiarization Program for Adults with Prader-Willi Syndrome." Adapted Physical Activity Quarterly 19, no. 2 (April 2002): 188–98. http://dx.doi.org/10.1123/apaq.19.2.188.

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The purpose of the project was to evaluate an underwater weighing (UWW) and residual lung volume (RV) familiarization program developed for adults with Prader-Willi syndrome (PWS). UWW was conducted on 15 adults (10 men, 5 women) with PWS following a UWW familiarization program. Repeated measures ANOVA revealed no difference in percent body fat derived from UWW over the four sessions, F(3, 27) = 0.80, p = .505, with an intraclass reliability coefficient of R = .93. There was, however, a significant difference in RV, F(3, 27) = 5.25, p = .006, with an intraclass reliability coefficient of R = .65. The familiarization program is recommended for implementation prior to measuring percent body fat via UWW. However, predicting the RV may be an easier and more consistent alternative to measuring the RV in adults with PWS.

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Oakland, Hannah, Phillip Joseph, Robert Naeije, Ahmed Elassal, Marjorie Cullinan, Paul M. Heerdt, and Inderjit Singh. "Arterial load and right ventricular-vascular coupling in pulmonary hypertension." Journal of Applied Physiology 131, no. 1 (July 1, 2021): 424–33. http://dx.doi.org/10.1152/japplphysiol.00204.2021.

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Pulmonary vascular impedance (PVZ) represents the most comprehensive measure of right ventricle (RV) afterload; however, measurement of this variable is complex. We demonstrate that characteristic impedance ( Zc) and a wave reflection coefficient, λ, can be derived from RV pressure waveform analysis. In addition, RV dysfunction in left heart disease is independent of its afterload. The current study provides a platform for future studies to examine the pharmacotherapeutic effects and prognosis of different measures of RV afterload.

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Lim, San Y., Rohayu Mohd Salleh, and Norhaidah Mohd Asrah. "Behaviours of Bursa Malaysia: a Multidimensional Network Analysis." International Journal of Engineering & Technology 7, no. 4.30 (November 30, 2018): 229. http://dx.doi.org/10.14419/ijet.v7i4.30.22126.

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In current practice, the similarities between two or more univariate time series of stocks are determined by using the Pearson correlation coefficient (PCC). However, the economic information might be misleading if the analysis applies only the univariate time series of stock price, as each stock is denoted by four types of prices. Therefore, multidimensional of stocks are taken into account in this paper. The similarities between two or more multi-dimensional of stocks are quantified by using Random Vector (RV) coefficient. Additionally, an algorithm is proposed due to the computational of RV coefficient is tedious and time-consuming when a large number of stocks are included. In this paper, the Malaysian stock network analysis in univariate and multivariate setting are conducted and analysed by using the PCC, RV coefficient, forest of all possible MSTs and centrality measures. In summary, there is some important economic information could not be brought out by univariate network analysis alone.

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PIAGGI, PAOLO, DANILO MENICUCCI, CLAUDIO GENTILI, GIACOMO HANDJARAS, ANGELO GEMIGNANI, and ALBERTO LANDI. "ADAPTIVE FILTERING AND RANDOM VARIABLES COEFFICIENT FOR ANALYZING FUNCTIONAL MAGNETIC RESONANCE IMAGING DATA." International Journal of Neural Systems 23, no. 03 (April 29, 2013): 1350011. http://dx.doi.org/10.1142/s0129065713500111.

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Functional magnetic resonance imaging (fMRI) is used to study brain functional connectivity (FC) after filtering the physiological noise (PN). Herein, we employ: adaptive filtering for removing nonstationary PN; random variables (RV) coefficient for FC analysis. Comparisons with standard techniques were performed by quantifying PN filtering and FC in neural vs. non-neural regions. As a result, adaptive filtering plus RV coefficient showed a greater suppression of PN and higher connectivity in neural regions, representing a novel effective approach to analyze fMRI data.

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Kurkin, Evgenii Igorevich, Vladislava Olegovna Chertykovtseva, and Yaroslav Vyacheslavovich Zakhvatkin. "Processing a Brookfield Rotational Viscometer Measurement Results in the MATLAB." Key Engineering Materials 834 (March 2020): 82–89. http://dx.doi.org/10.4028/www.scientific.net/kem.834.82.

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The Brookfield_to_MATLAB and ViscosityApproximation codes for processing of experiments results for determination of viscosity on a rotational Brookfield DV3T viscometer is developed in the MATLAB. The codes allow to carry out automatic capture data, to calculate the shear rate for standard spindles RV-1 ... RV-7, to sort the measurement results on temperatures, to combine the experimental data and to determine the coefficients of the Andrade type power-law model. Paper describes experiment results on determination of viscosity of the epoxy binder reinforced by short carbon fibers. The coefficients of the viscosity model are determined by the linear regression coefficients. The obtained determination coefficient shows a good agreement of the model with the experimental data. The results are used for study various contents of a mass fraction of fibers: 0%, 5%, 10%, and 15%.

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Schlich, Pascal, and Elisabeth Guichard. "Selection and classification of volatile compounds of apricot using the RV coefficient." Journal of Agricultural and Food Chemistry 37, no. 1 (January 1989): 142–50. http://dx.doi.org/10.1021/jf00085a034.

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Kamińska, Halszka, Łukasz A. Małek, Marzena Barczuk-Falęcka, and Bożena Werner. "Usefulness of three-dimensional echocardiography for assessment of left and right ventricular volumes in children, verified by cardiac magnetic resonance. Can we overcome the discrepancy?" Archives of Medical Science 17, no. 1 (January 5, 2021): 71–83. http://dx.doi.org/10.5114/aoms.2019.84215.

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IntroductionThe role of three-dimensional echocardiography (3D-ECHO) chamber quantification in children is still underestimated.Material and methodsIn 43 children 3D-ECHO measurements of end-diastolic (EDV) and end-systolic ventricular volumes (ESV) were compared to cardiac magnetic resonance (CMR) using Bland-Altman analysis and linear regression. The values of left and right ventricular volumes calculated in 3D-ECHO were compared with each other and verified by CMR.ResultsThe values of LV-EDV and LV-ESV measured in 3D-ECHO showed highly significant correlations with CMR (for LV-EDV r = 0.892, p < 0.00001; for LV-ESV r = 0.896, p < 0.00001). In the case of the right ventricle the correlation of 3D-ECHO results with CMR was still high (RV-EDV r = 0.848, p < 0.00001, RV-ESV r = 0.914, p < 0.00001), although mean RV-EDV and RV-ESV in 3D-ECHO were underestimated compared to CMR (by 38% for RV-EDV and 45% for RV-ESV). Correction of 3D-ECHO results using the coefficient of 1.38 and 1.45 for RV-EDV and RV-ESV, respectively, significantly improved the consistency of the results with CMR. 3D-ECHO offered lower mean values of right ventricular volumes compared to the left ventricle. The discrepancy was again reduced by the calculated coefficients.Conclusions3D-ECHO is a valuable tool for assessment of left ventricular volume, which strongly correlates and agrees with CMR. The right ventricular volumes calculated in 3D-ECHO tend to be significantly underestimated in comparison to CMR and corresponding left ventricular volumes obtained from 3D-ECHO. The use of coefficients developed by the study improves the consistency of right ventricular volumes measured by 3D-ECHO with results obtained by CMR and reduces the volumetric discrepancy between ventricles in 3D-ECHO.

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Doste, Ruben, Rafael Sebastian, Juan Francisco Gomez, David Soto-Iglesias, Alejandro Alcaine, Lluis Mont, Antonio Berruezo, Diego Penela, and Oscar Camara. "In silico pace-mapping: prediction of left vs. right outflow tract origin in idiopathic ventricular arrhythmias with patient-specific electrophysiological simulations." EP Europace 22, no. 9 (July 1, 2020): 1419–30. http://dx.doi.org/10.1093/europace/euaa102.

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Abstract Aims A pre-operative non-invasive identification of the site of origin (SOO) of outflow tract ventricular arrhythmias (OTVAs) is important to properly plan radiofrequency ablation procedures. Although some algorithms based on electrocardiograms (ECGs) have been developed to predict left vs. right ventricular origins, their accuracy is still limited, especially in complex anatomies. The aim of this work is to use patient-specific electrophysiological simulations of the heart to predict the SOO in OTVA patients. Methods and results An in silico pace-mapping procedure was designed and used on 11 heart geometries, generating for each case simulated ECGs from 12 clinically plausible SOO. Subsequently, the simulated ECGs were compared with patient ECG data obtained during the clinical tachycardia using the 12-lead correlation coefficient (12-lead ρ). Left ventricle (LV) vs. right ventricle (RV) SOO was estimated by computing the LV/RV ratio for each patient, obtained by dividing the average 12-lead ρ value of the LV- and RV-SOO simulated ECGs, respectively. Simulated ECGs that had virtual sites close to the ablation points that stopped the arrhythmia presented higher correlation coefficients. The LV/RV ratio correctly predicted LV vs. RV SOO in 10/11 cases; 1.07 vs. 0.93 P < 0.05 for 12-lead ρ. Conclusion The obtained results demonstrate the potential of the developed in silico pace-mapping technique to complement standard ECG for the pre-operative planning of complex ventricular arrhythmias.

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Moonseong Heo and K. Ruben Gabriel. "A permutation test of association between configurations by means of the rv coefficient." Communications in Statistics - Simulation and Computation 27, no. 3 (January 1998): 843–56. http://dx.doi.org/10.1080/03610919808813512.

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Moiseeva, N. A., T. Ya Churilova, T. V. Efimova, V. A. Artemiev, and E. Yu Skorokhod. "Spectral bio-optical properties of water of Atlantic sector of Antarctic." Marine Biological Journal 5, no. 4 (December 30, 2020): 69–78. http://dx.doi.org/10.21072/mbj.2020.05.4.06.

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Studies of variability of spectral bio-optical properties of water of Atlantic sector of Antarctic were carried out during the 79th cruise of the RV “Akademik Mstislav Keldysh” (11.01.2020–04.02.2020). Chlorophyll a and phaeopigment concentration varied in the layer studied from 0.1 to 1.8 mg·m−3, except for two stations with content reaching 2.2 and 4.4 mg·m−3. The relationship was revealed between light absorption coefficient by phytoplankton and chlorophyll a concentration at a wavelength, corresponding to spectrum maxima: aph(438) = 0.044 × Ca1.2, r2 = 0.84 (n = 117); aph(678) = 0.021 × Ca1.1, r2 = 0.89 (n = 117). Spectral distribution of light absorption coefficient by non-algal particles and colored dissolved organic matter was described by exponential function. Absorption parameterization coefficients were retrieved: (1) light absorption coefficient by non-algal particles (0.001–0.027 m−1) and by colored dissolved organic matter (0.016–0.19 m−1) at a wavelength of 438 nm; (2) spectral slope coefficients of these components (0.005–0.016 and 0.009–0.022 nm−1, respectively).

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Peixoto, Alberto Borges, Nathalie Jeanne Bravo-valenzuela, Wellington P. Martins, Rosiane Mattar, Antonio Fernandes Moron, and Edward Araujo Júnior. "Reference ranges for left, right and interventricular septum indices at 20 to 36+6 weeks of gestation derived using spectral myocardial tissue Doppler on Voluson ultrasound machines." Medical Ultrasonography 21, no. 3 (August 31, 2019): 279. http://dx.doi.org/10.11152/mu-1945.

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Aim: To establish reference range values for peak myocardial tissue Doppler velocity (MTD) and myocardial performance index (MPI) of the left ventricle (LV), the right ventricle (RV), and the interventricular septum (IVS) at 20 to 36+6 weeks of gestation using spectral tissue Doppler.Material and methods: This cross-sectional study was conducted among 360 lowrisk singleton pregnancies. MTD during systole (S’), and early (E’) and late diastole (A’), and MPI’ were assessed by placing sample volume at the basal segment of the LV free wall, the RV free wall, and the IVS, respectively. Polynomial regression was used to obtain the best-fit curves for MTD and MPI’ measurements as a function of gestational age (GA), and adjustments were made using the determination coefficient (R2). Intra- and inter-observer reproducibility was evaluated using the concordance correlation coefficient (CCC).Results: All MTD velocities (cm/s) progressively increased with advancing GA (p<0.0001). Mean LV MTD values were 4.19 to 6.86 for S’, 3.52 to 7.22 for E’, and 6.85 to 9.19 for A’; mean RV MTD were 4.85 to 7.97 for S’, 4.49 to 8.66 for E’, and 8.44 to 11.20 for A’; and mean IVS MTD values were 3.75 to 5.78 for S’, 3.34 to 5.79 for E’, and 5.88 to 7.98 for A’. LV MPI’, RV MPI’, and IVS MPI’ did not significantly change with advancing GA. The CCC values for MTD were predominantly greater than 0.70, while those for MPI’ were <0.70.Conclusions: Reference values for the fetal MTD and MPI’ of RV, LV and IVS using tissue Doppler between 20 and 36+6 weeks of gestation were described.

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Vanderpool, Rebecca R., Reena Puri, Alexandra Osorio, Kelly Wickstrom, Ankit A. Desai, Stephen M. Black, Joe G. N. Garcia, Jason X. J. Yuan, and Franz P. Rischard. "Surfing the right ventricular pressure waveform: methods to assess global, systolic and diastolic RV function from a clinical right heart catheterization." Pulmonary Circulation 10, no. 1 (January 2020): 204589401985099. http://dx.doi.org/10.1177/2045894019850993.

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Right ventricular (RV) function strongly associates with mortality in patients with pulmonary arterial hypertension (PAH). Current methods to determine RV function require temporal measurements of pressure and volume. The aim of the study was to investigate the feasibility of using right heart catheterization (RHC) measurements to estimate systolic and diastolic RV function. RV pressure and volume points were fit to P = α(eβV-1) to assess diastolic stiffness coefficient (β) and end-diastolic elastance (Eed). Single-beat methods were used to assess RV contractility (Ees). The effects of a non-zero unstressed RV volume (V0), RHC-derived stroke volume (SVRHC), and normalization of the end-diastolic volume (EDV) on estimates of β, Eed, and Ees were tested using Bland–Altman analysis in an incident PAH cohort (n = 32) that had both a RHC and cardiac magnetic resonance (CMR) test. RHC-derived measures of RV function were used to detect the effect of prostacyclin therapy in an incident PAH cohort and the severity of PAH in prevalent PAH (n = 21). A non-zero V0 had a minimal effect on β with a small bias and limits of agreement (LOA). Stroke volume (SV) significantly influenced estimates of β and Ees with a large LOA. Normalization of EDV had minimal effect on both β and Eed. RHC-derived β and Eed increased due to the severity of PAH and decreased due to three months of prostacyclin therapy. It is feasible to detect therapeutic changes in specific stiffness and elastic properties of the RV from signal-beat pressure-volume loops by using RHC-derived SV and normalizing RV EDV.

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Aronu, Charles, Godday Ebuh, Cecilia Okoli, and Rose Nwosu. "Comparison of Randomization method for RV coefficient and Permutation Method for Hotelling T-Squared." SOP Transactions on Statistics and Analysis 2014, no. 2 (July 31, 2014): 37–73. http://dx.doi.org/10.15764/stsa.2014.02003.

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Cretignier, M., X. Dumusque, R. Allart, F. Pepe, and C. Lovis. "Measuring precise radial velocities on individual spectral lines." Astronomy & Astrophysics 633 (January 2020): A76. http://dx.doi.org/10.1051/0004-6361/201936548.

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Context. Although the new generation of radial-velocity (RV) instruments such as ESPRESSO are expected to reach the long-term precision required to find other earths, the RV measurements are contaminated by some signal from stellar activity. This makes these detections hard. Aims. Based on real observations, we here demonstrate for the first time the effect of stellar activity on the RV of individual spectral lines. Recent studies have shown that this is probably the key for mitigating this perturbing signal. By measuring the line-by-line RV of each individual spectral line in the 2010 HARPS RV measurements of α Cen B, we study their sensitivity to telluric line contamination and line profile asymmetry. After selecting lines on which we are confident to measure a real Doppler-shift, we study the different effects of the RV signal that is induced by stellar activity on spectral lines based on their physical properties. Results. We estimate that at least 89% of the lines that appear in the spectrum of α Cen B for which we measure a reliable RV are correlated with the stellar activity signal (Pearson correlation coefficient R > 0.3 at 2σ). This can be interpreted as those lines being sensitive to the inhibition of the convective blueshift observed in active regions. Because the velocity of the convective blueshift increases with physical depth inside the stellar atmosphere, we find that the effect induced by stellar activity on the RV of individual spectral lines is inversely proportional to the line depth. The stellar activity signal can be mitigated down to ~0.8–0.9 m s−1 either by selecting lines that are less sensitive to activity or by using the difference between the RV of the spectral lines that are formed at different depths in the stellar atmosphere as an activity proxy. Conclusions. This paper shows for the first time that based on real observations of solar-type stars, it is possible to measure the RV effect of stellar activity on the RV of individual spectral lines. Our results are very promising and demonstrate that analysing the RV of individual spectral lines is probably one of the solutions to mitigate stellar activity signal in RV measurements down to a level enabling the detection of other earths.

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Solda, P. L., P. Pantaleo, S. Perlini, A. Calciati, G. Finardi, M. R. Pinsky, and L. Bernardi. "Continuous monitoring of right ventricular volume changes using a conductance catheter in the rabbit." Journal of Applied Physiology 73, no. 5 (November 1, 1992): 1770–75. http://dx.doi.org/10.1152/jappl.1992.73.5.1770.

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To assess the reliability of conductance (G) catheter for evaluating right ventricular (RV) volume changes, a miniature (3.5F) six-electrode catheter was developed and tested in 11 New Zealand rabbit hearts. In five animals the heart was excised; in six it was left in the thorax. RV conductance was recorded while the RV was filled with blood in 0.25-ml steps at different left ventricular (LV) volumes. Linear correlation of measured conductance vs. reference volumes was computed. RV conductance was highly correlated with reference volume [correlation coefficient (r) ranging from 0.991 to 0.999]. Slope of regression lines was not significantly affected by LV volume variations in 1-ml steps or by acute conductance changes of structures surrounding the heart, whereas the intercept was affected only by the 0- to 1-ml LV volume change. In four rabbits, RV conductance changes during a cardiac cycle [stroke volume- (SV) G] were compared in vivo with electromagnetic flow probe-derived estimates of SV (SVem) as stroke volume was varied by graded inferior vena caval occlusion. SV-G correlated well with SVem (r ranging from 0.92 to 0.96). This correlation persisted after the thorax was filled with saline; however, significant differences were found in individual slopes (P < 0.001). These results show that the conductance catheter has a potential to reliably monitor in vivo relative RV volume changes in small-animal hearts.

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van der Ploeg, Grant E., Simon M. Gunn, Robert T. Withers, Andrew C. Modra, and Alan J. Crockett. "Comparison of two hydrodensitometric methods for estimating percent body fat." Journal of Applied Physiology 88, no. 4 (April 1, 2000): 1175–80. http://dx.doi.org/10.1152/jappl.2000.88.4.1175.

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This study compared the two following hydrodensitometric methods for estimating percent body fat (%BF): 1) estimation of residual volume (RV) by helium dilution before and after measurement of immersed mass at RV, and 2) determination of immersed mass at a comfortable level of expiration (approximately functional residual capacity) with measurement of the associated gas volume by oxygen dilution. Twelve men [27.9 ± 7.5 (SD) yr; 79.32 ± 12.79 kg; 180.5 ± 9.9 cm] were tested for %BF via both methods on each of two separate visits within 3 days by using a counterbalanced design. The two helium dilution measurements yielded a technical error of measurement of 0.2% BF and an intraclass correlation coefficient of 0.999. Corresponding values for the oxygen dilution method were 0.4% BF and 0.999, respectively. There was no difference ( P = 0.80) between the helium dilution (16.9 ± 9.3% BF) and oxygen dilution (16.9 ± 9.4% BF) methods, and the individual differences ranged from −0.7 to 0.6% BF. The interclass correlation coefficient between the two methods was 0.999 with a SE of estimate of 0.4% BF. Whereas both methods were precise and reliable and yielded similar results, the oxygen dilution technique was more expedient and was preferred by the subjects because they were not required to exhale to RV.

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Borzou, Ahmad, Razie Yousefi, and Rovshan G. Sadygov. "Another look at matrix correlations." Bioinformatics 35, no. 22 (April 25, 2019): 4748–53. http://dx.doi.org/10.1093/bioinformatics/btz281.

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Abstract Motivation High throughput technologies are widely employed in modern biomedical research. They yield measurements of a large number of biomolecules in a single experiment. The number of experiments usually is much smaller than the number of measurements in each experiment. The simultaneous measurements of biomolecules provide a basis for a comprehensive, systems view for describing relevant biological processes. Often it is necessary to determine correlations between the data matrices under different conditions or pathways. However, the techniques for analyzing the data with a low number of samples for possible correlations within or between conditions are still in development. Earlier developed correlative measures, such as the RV coefficient, use the trace of the product of data matrices as the most relevant characteristic. However, a recent study has shown that the RV coefficient consistently overestimates the correlations in the case of low sample numbers. To correct for this bias, it was suggested to discard the diagonal elements of the outer products of each data matrix. In this work, a principled approach based on the matrix decomposition generates three trace-independent parts for every matrix. These components are unique, and they are used to determine different aspects of correlations between the original datasets. Results Simulations show that the decomposition results in the removal of high correlation bias and the dependence on the sample number intrinsic to the RV coefficient. We then use the correlations to analyze a real proteomics dataset. Availability and implementation The python code can be downloaded from http://dynamic-proteome.utmb.edu/MatrixCorrelations.aspx. Supplementary information Supplementary data are available at Bioinformatics online.

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Sharma, R. D. "Technical Note: On the possibly missing mechanism of 15 μm emission in the mesosphere–lower thermosphere (MLT)." Atmospheric Chemistry and Physics 15, no. 4 (February 17, 2015): 1661–67. http://dx.doi.org/10.5194/acp-15-1661-2015.

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Abstract. Accurate knowledge of the rate as well as the mechanism of excitation of the bending mode of CO2 is necessary for reliable modeling of the mesosphere–lower thermosphere (MLT) region of the atmosphere. Assuming the excitation mechanism to be thermal collisions with atomic oxygen, the rate coefficient derived from the observed 15 μm emission by space-based experiments (kATM = 6.0 × 10−12 cm3s−1) differs from the laboratory measurements (kLAB =(1.5-2.5) × 10−12 cm3s−1) by a factor of 2–4. The general circulation models (GCMs) of Earth, Venus, and Mars have chosen to use a median value of kGCM = 3.0 × 10−12 cm3s−1 for this rate coefficient. As a first step to resolve the discrepancies between the three rate coefficients, we attempt to find the source of disagreement between the first two. It is pointed out that a large magnitude of the difference between these two rate coefficients (kx ≡ kATM - kLAB) requires that the unknown mechanism involve one or both major species: N2, O. Because of the rapidly decreasing volume mixing ratio (VMR) of CO2 with altitude, the exciting partner must be long lived and transfer energy efficiently. It is shown that thermal collisions with N2, mediated by a near-resonant rotation-to-vibration (RV) energy transfer process, while giving a reasonable rate coefficient kVR for de-excitation of the bending mode of CO2, lead to vibration-to-translation kVT rate coefficients in the terrestrial atmosphere that are 1–2 orders of magnitude larger than those observed in the laboratory. It is pointed out that the efficient near-resonant rotation-to-vibration (RV) energy transfer process has a chance of being the unknown mechanism if very high rotational levels of N2, produced by the reaction of N and NO and other collisional processes, have a super-thermal population and are long lived. Since atomic oxygen plays a critical role in the mechanisms discussed here, it suggested that its density be determined experimentally by ground- and space-based Raman lidars proposed earlier.

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Coertjens, Patrícia Chaves, Marli Maria Knorst, Anelise Dumke, Adriane Schmidt Pasqualoto, João Riboldi, and Sérgio Saldanha Menna Barreto. "Can the single-breath helium dilution method predict lung volumes as measured by whole-body plethysmography?" Jornal Brasileiro de Pneumologia 39, no. 6 (December 2013): 675–85. http://dx.doi.org/10.1590/s1806-37132013000600006.

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OBJECTIVE: To compare TLC and RV values obtained by the single-breath helium dilution (SBHD) method with those obtained by whole-body plethysmography (WBP) in patients with normal lung function, patients with obstructive lung disease (OLD), and patients with restrictive lung disease (RLD), varying in severity, and to devise equations to estimate the SBHD results.METHODS: This was a retrospective cross-sectional study involving 169 individuals, of whom 93 and 49 presented with OLD and RLD, respectively, the remaining 27 having normal lung function. All patients underwent spirometry and lung volume measurement by both methods.RESULTS: TLC and RV were higher by WBP than by SBHD. The discrepancy between the methods was more pronounced in the OLD group, correlating with the severity of airflow obstruction. In the OLD group, the correlation coefficient of the comparison between the two methods was 0.57 and 0.56 for TLC and RV, respectively (p < 0.001 for both). We used regression equations, adjusted for the groups studied, in order to predict the WBP values of TLC and RV, using the corresponding SBHD values. It was possible to create regression equations to predict differences in TLC and RV between the two methods only for the OLD group. The TLC and RV equations were, respectively, ∆TLCWBP-SBHD in L = 5.264 − 0.060 × FEV1/FVC (r2= 0.33; adjusted r2 = 0.32) and ∆RVWBP-SBHD in L = 4.862 − 0.055 × FEV1/FVC (r2= 0.31; adjusted r2 = 0.30).CONCLUSIONS: The correction of TLC and RV results obtained by SBHD can improve the accuracy of this method for assessing lung volumes in patients with OLD. However, additional studies are needed in order to validate these equations.

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Yin, Kedong, Zhe Liu, Chong Huang, and Peide Liu. "TOPOLOGICAL STRUCTURAL ANALYSIS OF CHINA'S NEW ENERGY STOCK MARKET: A MULTI-DIMENSIONAL DATA NETWORK PERSPECTIVE." Technological and Economic Development of Economy 26, no. 5 (May 26, 2020): 1030–51. http://dx.doi.org/10.3846/tede.2020.12723.

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In this paper, we apply an RV coefficient network to investigate the topological structure of China’s new energy stock market via daily prices of 60 component stocks of CSI (China Stock Index) New Energy Index spanning the period January 4, 2012 to March 29, 2019. Compared with the Pearson correlation coefficient, RV coefficient can better reflect the similarity between stocks from the perspective of multi-dimensional data. The empirical result indicates that (1) the scale-free characteristics of China’s new energy stock market are not significant; (2) the new energy storage is the leading sub-sector of the new energy sector and the new energy interactive equipment plays a connecting role between renewable energy production and new energy storage; (3) the most influential stock in the network is Group DMEGC Magnetics Co., Ltd., Xiamen Tungsten Co., Ltd. and GEM Co., Ltd. play an important role in the network connection. These findings are of great significance to understand the interaction between Chinese new energy stocks and the pricing mechanism of stocks. The authority should pay more attention to the new energy storage industry. Investor’s portfolios can be optimized according to the influence assessment of stocks and sub-sectors.

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Adams, Dean C. "Evaluating modularity in morphometric data: challenges with the RV coefficient and a new test measure." Methods in Ecology and Evolution 7, no. 5 (January 6, 2016): 565–72. http://dx.doi.org/10.1111/2041-210x.12511.

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Matsumoto, Takeshi, Jun Ebata, Hiroyuki Tachibana, Masami Goto, and Fumihiko Kajiya. "Transmural microcirculatory blood flow distribution in right and left ventricular free walls of rabbits." American Journal of Physiology-Heart and Circulatory Physiology 277, no. 1 (July 1, 1999): H183—H191. http://dx.doi.org/10.1152/ajpheart.1999.277.1.h183.

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Within-layer regional myocardial flows in the left and right ventricles (LV, RV) and in LV with increased myocardial workload (β1-adrenoceptor stimulation) were studied transmurally in anesthetized rabbits. Myocardial flow distribution was visualized with resolutions between 0.1 × 0.1- and 1 × 1-mm2 pixels, using digital radiography combined with the3H-labeled desmethylimipramine deposition technique. The spatial pattern of flow distribution was quantitated by the coefficient of variation of regional flows (CV, related to global flow heterogeneity) and the correlation between adjacent regional flows (CA, inversely related to local flow randomness). CV was lower in LV than in RV [ P < 0.05, nonparametric 2-way analysis of variance (NANOVA)]. When resolution was lowered from 0.1 × 0.1- to 1 × 1-mm2 pixels, CV decreased by 70% in both LV and RV. CA was higher in LV than in RV ( P < 0.05, NANOVA); the interventricular difference in CA was large over the resolutions between 0.4 × 0.4- and 1 × 1-mm2 pixels. In LV, both CV and CA increased with depth of myocardium ( P < 0.05, NANOVA); in subendocardium CV was high comparable with CV in RV ( P = 0.47, NANOVA). The enhancement of myocardial workload decreased CV and tended to decrease CA in LV subendocardium ( P < 0.05, P = 0.06, respectively; NANOVA). We conclude that 1) microregional flow distribution is less heterogeneous and less random in LV than in RV; 2) transmurally, in LV subendocardium global flow heterogeneity was the highest whereas local flow randomness was the lowest, so that clusters of low- or high-flow regions exist in this LV layer; and 3) global flow heterogeneity decreased and local flow randomness tended to increase (flow homogenizing occurred) in LV subendocardium with increasing myocardial workload. Thus the distributed pattern of myocardial microregional flows may be adaptable to local myocardial metabolic change.

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Lord, Rachel N., Keith George, Helen Jones, John Somauroo, and David Oxborough. "Reproducibility and feasibility of right ventricular strain and strain rate (SR) as determined by myocardial speckle tracking during high-intensity upright exercise: a comparison with tissue Doppler-derived strain and SR in healthy human hearts." Echo Research and Practice 1, no. 1 (September 2014): 31–41. http://dx.doi.org/10.1530/erp-14-0011.

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This study aimed to establish feasibility for myocardial speckle tracking (MST) and intra-observer reliability of both MST and tissue velocity imaging (TVI)-derived right ventricular (RV) strain (ε) and strain rate (SR) at rest and during upright incremental exercise. RV ε and SR were derived using both techniques in 19 healthy male participants. MST-derived ε and SR were feasible at rest (85% of segments tracked appropriately). Feasibility reduced significantly with progressive exercise intensity (3% of segments tracking appropriately at 90% maximum heart rate (HRmax)). Coefficient of variations (CoVs) of global ε values at rest was acceptable for both TVI and MST (7–12%), with low bias and narrow limits of agreement. Global SR data were less reliable for MST compared with TVI as demonstrated with CoV data (systolic SR=15 and 61%, early diastolic SR=16 and 17% and late diastolic SR=26 and 31% respectively). CoVs of global RV ε and SR obtained at 50% HRmax were acceptable using both techniques. As exercise intensity increased to 70 and 90% HRmax, reliability of ε and SR values reduced with larger variability in MST. We conclude that RV global and regional ε and SR data are feasible, comparable and reliable at rest and at 50% HRmax using both MST and TVI. Reliability was reduced during higher exercise intensities with only TVI acceptable for clinical and scientific use.

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Bonisławska, Małgorzata, Arkadiusz Nędzarek, Arkadiusz Drost, Agnieszka Rybczyk, and Agnieszka Tórz. "The application of ceramic membranes for treating effluent water from closed-circuit fish farming." Archives of Environmental Protection 42, no. 2 (June 1, 2016): 59–66. http://dx.doi.org/10.1515/aep-2016-0012.

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Abstract The aim of the study was to analyze and assess the possibility of using a two-stage filtration system with ceramic membranes: a 3-tube module with 1.0 kDa cut-off (1st stage) and a one-tube module with 0.45 kDa cut-off (2nd stage) for treating effluent water from a juvenile African catfish aquaculture. The study revealed that during the 1st filtration stage of the effluent water, the highest degrees of retention were obtained with respect to: suspended solids SS (rejection coefficient RI=100%), turbidity (RI=99.40%), total iron (RI=89.20%), BOD5 (RI=76.0%), nitrite nitrogen (RI=62.30%), and CODCr (RI=41.74%). The 2nd filtration stage resulted in a lower reduction degree of the tested indicators in comparison to the 1st filtration stage. At the 2nd stage, the highest values of the rejection coefficient were noted in for the total iron content (RIV=100%), CODCr (RIV=59.52%; RV=64.28%, RVI=63.49%) and turbidity (RIV and RV = 45.0%, RVI=50.0%). The obtained results indicate that ceramic membranes (with 1.0 and 0.45 kDa cut-offs) may be used in recirculation aquaculture systems as one of the stages of effluent water treatment.

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Yi, Cancan, Xing Wang, Yajun Zhu, and Wei Ke. "A Novel Adaptive Mode Decomposition Method Based on Reassignment Vector and Its Application to Fault Diagnosis of Rolling Bearing." Applied Sciences 10, no. 16 (August 7, 2020): 5479. http://dx.doi.org/10.3390/app10165479.

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To solve the problem that the random distribution of noise in the time-frequency (TF) plane largely affects the readability of TF representations, a novel signal adaptive decomposition algorithm processed in TF domain, which provides adequate information about the time-varying instantaneous frequency, is presented in this paper. The theoretical basis of this algorithm is short-time Fourier transform (STFT). The research into the algorithm comprises two steps: the TF plane denoising takes sparse low-rank matrix estimation as a priority and then achieves signal decomposition based on reassignment vector (RV). A low-rank matrix approximation scheme, which exploits the sparse properties of the TF transformation coefficient and uses non-convex penalty, is put forward to obtain clean STFT. Then, a new approach called RV, which is different from the traditional mode decomposition methods such as Empirical Mode Decomposition (EMD), is used to estimate the characteristic curve corresponding to the TF ridges of the interested modes. Based on the classical reassignment method, RV has a solid theory foundation. Moreover, it can identify different signal components such as stationary signal, modulating signal and impulse characteristic. Combining the advantages of low-rank matrix approximation approach and those of RV defined in TF plane, a novel signal adaptive decomposition method is proposed in this paper to identify fault characteristics. To illustrate the effectiveness of the method, fault signals of rolling bearing under stationary condition and time-varying speed are respectively analyzed.

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Townsley, M. I., R. J. Korthuis, and A. E. Taylor. "Effects of arachidonate on permeability and resistance distribution in canine lungs." Journal of Applied Physiology 58, no. 1 (January 1, 1985): 206–10. http://dx.doi.org/10.1152/jappl.1985.58.1.206.

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In this study, 14 canine lung lobes were isolated and perfused with autologous blood at constant pressure (CP) or constant flow (CF). Pulmonary capillary pressure (Pc) was measured via venous occlusion or simultaneous arterial and venous occlusions. Arterial and venous pressures and blood flow were measured concurrently so that total pulmonary vascular resistance (RT) as well as pre- (Ra) and post- (Rv) capillary resistances could be calculated. In both CP and CF perfused lobes, 5-min arachidonic acid (AA) infusions (0.085 +/- 0.005 to 2.80 +/- 0.16 mg X min-1 X 100 g lung-1) increased RT, Rv, and Pc (P less than 0.05 at the highest dose), while Ra was not significantly altered and Ra/Rv fell (P less than 0.05 at the highest AA dose). In five CP-perfused lobes, the effect of AA infusion on the pulmonary capillary filtration coefficient (Kf,C) was also determined. Neither low-dose AA (0.167 +/- 0.033 mg X min-1 X 100 g-1) nor high-dose AA (1.35 +/- 0.39 mg X min-1 X 100 g-1) altered Kf,C from control values (0.19 +/- 0.02 ml X min-1 X cmH2O-1 X 100 g-1). The hemodynamic response to AA was attenuated by prior administration of indomethacin (n = 2). We conclude that AA infusion in blood-perfused canine lung lobes increased RT and Pc by increasing Rv and that microvascular permeability is unaltered by AA infusion.

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Chen, Pengyu. "On the Diversity-Based Weighting Method for Risk Assessment and Decision-Making about Natural Hazards." Entropy 21, no. 3 (March 11, 2019): 269. http://dx.doi.org/10.3390/e21030269.

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The entropy-weighting method (EWM) and variation coefficient method (VCM) are two typical diversity-based weighting methods, which are widely used in risk assessment and decision-making for natural hazards. However, for the attributes with a specific range of values (RV), the weights calculated by EWM and VCM (abbreviated as WE and WV) may be irrational. To solve this problem, a new indicator representing the dipartite degree is proposed, which is called the coefficient of dipartite degree (CDD), and the corresponding weighting method is called the dipartite coefficient method (DCM). Firstly, based on a large amount of statistical data, a comparison between the EWM and VCM is carried out. It is found that there is a strong correlation between the weights calculated by the EWM and VCM (abbreviated as WE and WV); however, in some cases the difference between WE and WV is big. Especially when the diversity of attributes is high, WE may be much larger than WV. Then, a comparison of the DCM, EWM and VCM is carried out based on two case studies. The results indicate that DCM is preferred for determining the weights of the attributes with a specific RV, and if the values of attributes are large enough, the EWM and VCM are both available. The EWM is more suitable for distinguishing the alternatives, but prudence is required when the diversity of an attribute is high. Finally, the applications of the diversity-based weighting method in natural hazards are discussed.

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Wang, Yanhai, Wei Jiang, Shengguo Cheng, Pengcheng Song, and Cong Mao. "Effects of the impact angle on the coefficient of restitution in rockfall analysis based on a medium-scale laboratory test." Natural Hazards and Earth System Sciences 18, no. 11 (November 19, 2018): 3045–61. http://dx.doi.org/10.5194/nhess-18-3045-2018.

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Abstract. The reliability of a computer program simulating rockfall trajectory depends on the ascertainment of reasonable values for the coefficients of restitution, which typically vary with the kinematic parameters and terrain conditions. The effects of the impact angle with respect to the slope on the coefficients of restitution have been identified and studied using small-scale laboratory tests. To investigate whether the existing conclusion based on small-scale laboratory tests is valid when the test scale changes as well as the role of rotation in the effect of the impact angle on the coefficients of restitution, this study performed a medium-scale laboratory test using spherical limestone polyhedrons to impact concrete slabs. Free-fall tests are conducted, and the velocities before and after the impact are obtained by a 3-D motion capture system. The comparison of results between our test and the existing small-scale tests verified that several general laws occur when accounting for the effect of the impact angle, regardless of the test scales and conditions. Increasing the impact angle will induce reductions in the normal coefficient of restitution Rn, the kinematic coefficient of restitution Rv and the kinetic energy coefficient of restitution RE, whereas it will lead to increases in the tangential coefficient of restitution Rt. The rotation plays an important role in the effect of the impact angle. A higher percentage of kinetic energy converted to rotational energy always induces a higher normal coefficient of restitution Rn and a lower tangential coefficient of restitution Rt. As the impact angle decreases, the ratio between the rebound angle β and the impact angle α increases, and the percentage of kinetic energy dissipated in rotation as the collision became higher. Considering that the effect of block shape and the detailed impact orientations are not involved in the present study, the test results are valid for trajectory simulation codes based on a lumped-mass model and can be referenced in the trajectory predication of spherical rocks impacting hard surfaces using a rigid body model.

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Mohammed, Faez A. E., Rahma Bchitou, Mohamed Boulmane, Ahmed Bouhaouss, and Dominique Guillaume. "Modeling of the Distribution of Heavy Metals and Trace Elements in Argan Forest Soil and Parts of Argan Tree." Natural Product Communications 8, no. 1 (January 2013): 1934578X1300800. http://dx.doi.org/10.1177/1934578x1300800105.

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The transfer of heavy metals and trace elements from argan forest soil into the wood, leaves, almonds, and argan oil was studied. Analyzed metals were: chromium, cadmium, copper, zinc, lead, calcium, phosphorus, potassium, and magnesium. Correlations linking different behaviors of the studied heavy metals and trace elements observed by multidimensional analysis were attributed to partial-spatial variations. Whereas the RV-coefficient of wood, leaf, almond and oil groups was high, the soil group correlated poorly with the other groups.

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Druk, I. V., G. I. Nechaeva, V. E. Smyalovskiy, V. V. Potapov, I. V. Kolmenkova, and N. Yu Sidorova. "Tolerance for physical activity and speckle tracking-characteristics of right ventricle deformation in young patients with connective tissue dysplasia." Patologiya krovoobrashcheniya i kardiokhirurgiya 18, no. 1 (October 10, 2015): 42. http://dx.doi.org/10.21688/1681-3472-2014-1-42-46.

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In order to clarify the state of physical performance of young patients with signs of poorly differentiated connective tissue dysplasia (CTD) in comparison with morphometric and functional performance of the heart, an open comparative study was conducted. Speckle tracking (ST) echocardiography was applied for quantitative evaluation of deformation properties of the right ventricle (RV) free wall. The study included 549 patients with CTD (330 men, mean age 23.51 8.67). An average diagnostic coefficient of CTD was 28.8410.76. The main symptoms were CTD changes in the musculoskeletal system (n = 549), cardiovascular system (n=409), skin (n=169) and respiratory system (n=119). 44 patients with CTD and low exercise tolerance and 13 healthy volunteers were tested by using a speckle tracking technique. In the group of patients with CTD a significantly higher incidence of low exercise tolerance and dystonic reactions to physical exertion were observed. Also recorded were changes in the ST-parameters of RV systolic strain.

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Chauhan, S., H. S. Srivastava, and P. Patel. "IMPROVED PARAMETERIZATION OF WATER CLOUD MODEL FOR HYBRID-POLARIZED BACKSCATTER SIMULATION USING INTERACTION FACTOR." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W2 (July 5, 2017): 61–66. http://dx.doi.org/10.5194/isprs-archives-xlii-4-w2-61-2017.

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The prime aim of this study was to assess the potential of semi-empirical water cloud model (WCM) in simulating hybrid-polarized SAR backscatter signatures (RH and RV) retrieved from RISAT-1 data and integrate the results into a graphical user interface (GUI) to facilitate easy comprehension and interpretation. A predominant agricultural wheat growing area was selected in Mathura and Bharatpur districts located in the Indian states of Uttar Pradesh and Rajasthan respectively to carry out the study. The three-date datasets were acquired covering the crucial growth stages of the wheat crop. In synchrony, the fieldwork was organized to measure crop/soil parameters. The RH and RV backscattering coefficient images were extracted from the SAR data for all the three dates. The effect of four combinations of vegetation descriptors (V1 and V2) viz., LAI-LAI, LAI-Plant water content (PWC), Leaf water area index (LWAI)-LWAI, and LAI-Interaction factor (IF) on the total RH and RV backscatter was analyzed. The results revealed that WCM calibrated with LAI and IF as the two vegetation descriptors simulated the total RH and RV backscatter values with highest R2 of 0.90 and 0.85 while the RMSE was lowest among the other tested models (1.18 and 1.25 dB, respectively). The theoretical considerations and interpretations have been discussed and examined in the paper. The novelty of this work emanates from the fact that it is a first step towards the modeling of hybrid-polarized backscatter data using an accurately parameterized semi-empirical approach.

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Barros, Fernanda Silveira Bello, Antonio Fernandes Moron, Liliam Cristine Rolo, Luciane Alves Rocha, Wellington P. Martins, Gabriele Tonni, Luciano Marcondes Machado Nardozza, and Edward Araujo Júnior. "Fetal Myocardial Wall Area: Constructing a Reference Range by Means of Spatiotemporal Image Correlation in the Rendering Mode." Fetal Diagnosis and Therapy 37, no. 1 (July 31, 2014): 44–50. http://dx.doi.org/10.1159/000363653.

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Objective: To establish the reference range of the myocardial wall area in the fetus using three-dimensional ultrasound in the rendering mode. Methods: A prospective, cross-sectional study including 371 singleton, uncomplicated pregnancies at 20 weeks 0 day to 33 weeks 6 days of gestation was carried out. Cardiac volumes were obtained using spatiotemporal image correlation (STIC) at the level of the four-chamber view. The end-diastolic myocardial area of the both ventricles was measured manually. The intraclass correlation coefficient (ICC) was used to assess intra- and interobserver concordance. Results: The mean myocardial area of the fetal right ventricular (RV) wall ranged from 0.86 ± 0.23 cm2 at 20 weeks 0 day to 2.75 ± 0.69 cm2 at 33 weeks 6 days of gestation. The mean myocardial area of the fetal left ventricular (LV) wall ranged from 0.82 ± 0.20 cm2 at 20 weeks 0 day to 2.49 ± 0.59 cm2 at 33 weeks 6 days of gestation. In addition, intra- and interobserver concordance for the myocardial area of the RV and LV walls was good, with ICC values of 0.94, 0.95, 0.85, and 0.93, respectively. Conclusions: The reference range for the myocardial area of the RV and LV walls was determined by cardio-STIC in the rendering mode at 20 weeks 0 day to 33 weeks 6 days of gestation, with good concordance between values.

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Khanduja, Sudesh K., and Jayanti Saha. "Generalized Hensel's lemma." Proceedings of the Edinburgh Mathematical Society 42, no. 3 (October 1999): 469–80. http://dx.doi.org/10.1017/s0013091500020460.

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Let (K, v) be a complete, rank-1 valued field with valuation ring Rv, and residue field kv. Let vx be the Gaussian extension of the valuation v to a simple transcendental extension K(x) defined by The classical Hensel's lemma asserts that if polynomials F(x), G0(x), H0(x) in Rv[x] are such that (i) vx(F(x) – G0(x)H0(x)) > 0, (ii) the leading coefficient of G0(x) has v-valuation zero, (iii) there are polynomials A(x), B(x) belonging to the valuation ring of vx satisfying vx(A(x)G0(x) + B(x)H0(x) – 1) > 0, then there exist G(x), H(x) in K[x] such that (a) F(x) = G(x)H(x), (b) deg G(x) = deg G0(x), (c) vx(G(x)–G0(x)) > 0, vx(H(x) – H0(x)) > 0. In this paper, our goal is to prove an analogous result when vx is replaced by any prolongation w of v to K(x), with the residue field of wa transcendental extension of kv.

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Roy, B. J., V. H. Pitts, and M. I. Townsley. "Pulmonary vascular response to angiotensin II in canine pacing-induced heart failure." American Journal of Physiology-Heart and Circulatory Physiology 271, no. 1 (July 1, 1996): H222—H227. http://dx.doi.org/10.1152/ajpheart.1996.271.1.h222.

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The effects of angiotensin II(ANG II) on pulmonary vascular resistance and microvascular permeability were studied in isolated, blood-perfused, ventilated canine lung lobes from control animals (n = 40) and animals with pacing-induced heart failure (n = 15). Conditioned dogs were paced (245 beats/min) for 30.6 +/- 0.9 (SE) days until left ventricular shortening fraction decreased by 56% (P < 0.05). Baseline pulmonary arterial resistance (Ra) (19.1 +/- 1.6 vs. 8.0 +/- 1.1 cmH2O.1(-1).min.100g) and venous resistance (Rv) (17.1 +/- 2.3 vs. 7.8 +/- 1.0 cmH2O.1(-1).min.100 g) were greater (P < 0.05) in the paced group compared with controls, respectively. Increments in Ra (delta Ra) and Rv(delta Rv) were measured after intra-arterial boluses of ANG II (1-10 micrograms). ANG II produced a dose-dependent response in delta Ra that was enhanced after pacing (P < 0.05). There was no effect on delta Rv in either group. At increased venous pressure (Pv = 20 cmH2O), the increments in delta Ra were significantly attenuated in both groups. In control lobes at low Pv, delta Ra and delta Rv both tended to decrease with increased lobar blood flow, suggesting that blood flow affects the pulmonary vascular response of ANG II. The baseline capillary filtration coefficient (Kf,c) was not different in the paced group compared with control, nor was there any effect of ANG II on Kf,c in the paced group. However, Kf,c did increase after ANG II in the control groups evaluated at either low or high Pv (P < 0.05). This difference in Kf,c was not seen if the experiment was done at increased Pv but without ANG II administration. We conclude that the pulmonary vasoconstrictor activity of ANG II is modestly enhanced in canine pacing-induced heart failure. Nonetheless, ANG II does not likely contribute to increased pulmonary vascular resistance in vivo in heart failure, since this effect was abolished at increased Pv. Finally, the absence of any effect of ANG II on pulmonary microvascular permeability in the paced group is suggestive of some adaptive remodeling of the capillary endothelial barrier.

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Wang, Han, and Wei Ming Zeng. "An Improved RV Based Fuzzy Cluster Analysis (IRVFCA) Method for Task-Related Functional MRI Data Analysis." Applied Mechanics and Materials 427-429 (September 2013): 1570–73. http://dx.doi.org/10.4028/www.scientific.net/amm.427-429.1570.

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Functional magnetic resonance imaging (fMRI) has become one of the important tools of functional connectivity studies of the human brain. Fuzzy clustering method (FCM) is a common method for analysis of FMRI data. Traditional FCA methods measure the similarity between the BOLD time course of a centroid and the ones of all other voxels in the brain on the basis of Pearson correlation coefficient. This article puts forward a multi-voxel-based similarity measure, an improved RV (IRV) measure, which takes the hypothesis into account that the function homogeneous voxels of brain volume are spatially clustered within a local region. Experimental validation is presented through four visual fMRI data sets which shows that the IRVFCA method not only has improved the speed of FCA, but has comparatively raised the accuracy of the method.

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Hou, Sizhe, Jiangrui Chen, Lianqian Yin, Wei Zhang, Xiaojie Liu, and Haoting Li. "Realized Volatility Analysis from Various Perspectives Based on Hilbert Huang Transform." International Journal of Economics and Finance 7, no. 12 (November 24, 2015): 189. http://dx.doi.org/10.5539/ijef.v7n12p189.

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In this paper, based on results of the volatility of stock returns after the Hilbert Huang Transform, to research the influential factors of volatility composition, the influential factor model of yield volatility is established. This model studies the volatility from three angles respectively: the hysteresis of impact, the influence degree and the affect correlation. For the hysteresis of impact, this paper uses the model to determine lag phases of different IMF of volatility. For the influence degree, after using principal component analysis to eliminate the multicollinearity between different IMF, we calculate direct contribution, correlation coefficient and variable coefficient to quantify the influence degree of IMF on RV, BV and JV, the independence degree and the information abundance. For affect correlation, this paper adopts four different distance calculating methods and grey correlation method to depict the connection degree between RV and IMFin different dimensions. Finally, this paper uses the data of China's financial markets to carry on the empirical analysis, and explores various characteristics of realized volatility through comprehensive influence degree, in order to provide new perspectives and ideas for financial analysis and forecast. provide new perspectives and ideas for financial analysis and forecast.

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Noonan, T. C., W. M. Selig, D. F. Kern, and S. B. Malik. "Mechanism of peptidoleukotriene-induced increases in pulmonary transvascular fluid filtration." Journal of Applied Physiology 61, no. 5 (November 1, 1986): 1928–34. http://dx.doi.org/10.1152/jappl.1986.61.5.1928.

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We examined the effects of leukotrienes C4 (LTC4) and D4 (LTD4) (1 microgram) on the pulmonary vascular filtration coefficient, a measure of vessel wall conductivity to water, and the alterations in pulmonary vascular resistance (PVR) in isolated-perfused guinea pig lungs. We also assessed whether LTC4 and LTD4 increased the permeability to albumin in cultured monolayers of pulmonary artery endothelial cells. In Ringer-perfused and blood-perfused lungs, LTC4 resulted in increases in pulmonary arterial pressure (Ppa) and the pulmonary capillary pressure (Pcap) measured as the equilibration pressure after simultaneous pulmonary arterial and venous occlusions. Pulmonary venous resistance (Rv) increased to a greater extent than arterial resistance (Ra) in both Ringer-perfused and blood-perused lungs challenged with LTC4. The greater increase in PVR in blood-perfused lungs corresponded with a greater elevation of lung effluent thromboxane B2 (TxB2) concentration. The LTC4-stimulated increase in PVR was prevented by pretreatment with meclofenamate (10(-4) M). LTD4 also induced rapid increases in Ppa and Pcap in both Ringer-perfused and blood-perfused lungs; however, Ppa decreased before stabilizing at a pressure higher than base line. The increases in Rv with LTD4 were greater than Ra. The LTD4-stimulated increases in Ra and Rv also paralleled the elevation in TxB2 concentration. As with LTC4, the increases in Ppa, Pcap, PVR, and TxB2 concentration were greater in blood-perfused than in Ringer-perfused lungs. Pretreatment with meclofenamate reduced the magnitude of the initial increase in Ppa, but did not prevent the response.(ABSTRACT TRUNCATED AT 250 WORDS)

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Lertphokanont, Vitchuda, Takayuki Sato, Minoru Ota, Keishi Yamaguchi, and Kai Egashira. "Surface Quality of Textured Surface on Cylindrical Inner Surface Using Whirling Electrical Discharge Texturing." Advanced Materials Research 797 (September 2013): 338–43. http://dx.doi.org/10.4028/www.scientific.net/amr.797.338.

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Whirling Electrical Discharge Texturing (WEDT) was developed to create microstructures. It was thought that textured surface with low surface roughness could reduce friction coefficient on the sliding parts. In this research, surface quality was studied to evaluate the quality of WEDT textured surface. Surface quality was evaluated in terms of the surface roughness and surface integrity which were characterized by microstructure, composition and residual stress of the textured surface. The value of Rp and Rv of textured surface after finishing with improved finishing method were obtained as expected for low surface roughness to reduce friction coefficient. In addition, it was clarified that microstructure and composition of textured surface after texturing with WEDT and finishing with lapping-film depend on feed speed. Furthermore, the compressive residual stress was presented on WEDT textured surface and depended on feed speed. It was confirmed that good surface quality of textured surface could be obtained by WEDT.

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Stachowicz, Katarzyna, Luiz F. Brito, Hinayah R. Oliveira, Stephen P. Miller, and Flávio S. Schenkel. "Assessing genetic diversity of various Canadian sheep breeds through pedigree analyses." Canadian Journal of Animal Science 98, no. 4 (December 1, 2018): 741–49. http://dx.doi.org/10.1139/cjas-2017-0187.

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The loss of genetic variability in a population will drastically affect the success of a breeding program by reducing selection response and fitness and, consequently, affecting reproduction, resilience, and production efficiency. The objective of this study was to perform an in-depth analysis of the pedigree of the Canadian sheep breeds to assess the levels of inbreeding, effective population size, and other metrics of genetic diversity, which included the five most important sheep breeds in Canada: Dorset, Polypay (PO), Rideau-Arcott, Romanov (RV), and Suffolk, using a large dataset (1 336 926 animals). As measures of genetic diversity, effective population size, inbreeding coefficient, effective number of founders, effective number of founder genomes, effective number of nonfounders, and effective number of ancestors were estimated. The completeness and depth of the Canadian sheep pedigree datasets were reasonably high, with <20% parental information missing. More attention should be given to PO breed, which was found to have the smallest effective population size (55), and RV breed, which had the highest average level of inbreeding (4.8%). Techniques such as optimum contribution selection and minimum coancestry mating could be used to minimize the inbreeding of future generations, while maintaining genetic progress at a desirable level.

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White, Paul A., Carl I. O. Brookes, Hanne Ravn, Vibeke Hjortdal, Rajiv R. Chaturvedi, and Andrew N. Redington. "Validation and utility of novel volume reduction technique for determination of parallel conductance." American Journal of Physiology-Heart and Circulatory Physiology 280, no. 1 (January 1, 2001): H475—H482. http://dx.doi.org/10.1152/ajpheart.2001.280.1.h475.

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The parallel conductance volume, created by the conductivity of structures surrounding the ventricular blood pool, can be estimated by using a saline dilution technique. This paper examines the use of a novel volume reduction method, during a standard vena caval preload reduction maneuver, as an alternative to the routinely used saline dilution method to calibrate conductance catheter measurements in the left (LV) and right ventricle (RV) of animals and humans. The serial reproducibility of both methods was examined by measurement of percent difference, and by assessing the coefficient of repeatability 1) between two measurements within the same subject, 2) between the two techniques, and 3) interobserver variability. The effect of ventricular size and contractile state on the volume reduction technique was also observed. It was essential to ensure the technique was not affected by inotropic state. The volume reduction technique and saline dilution method were repeated at three different loading states (baseline, 5, and 10 μg · kg−1 · min−1 of dobutamine). The coefficient of repeatability between serial measurements was similar for both the volume reduction and saline dilution methods, and good interobserver variability was demonstrated. The volume reduction technique was compared with the saline dilution technique over a large range of ventricular sizes. No significant difference was observed in the RV or LV of adult humans or in the LV of neonatal pigs and children. There was no significant effect on either the saline dilution or the volume reduction technique as the inotropic state increased. In conclusion, the volume reduction technique is neither affected by ventricular size nor contractile state, is repeatable between different observers, and can be used to substitute the saline dilution method when preload reduction of the ventricle is being employed.

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45

Choi, JinCheol, Donghuan Lu, Mirza Faisal Beg, Jinko Graham, and Brad McNeney. "The Contribution Plot: Decomposition and Graphical Display of the RV Coefficient, with Application to Genetic and Brain Imaging Biomarkers of Alzheimer’s Disease." Human Heredity 84, no. 2 (2019): 59–72. http://dx.doi.org/10.1159/000501334.

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Gao, Yanjun, and Yongqiang Zhang. "Effects of the Three Gorges Project on Runoff and Related Benefits of the Key Regions along Main Branches of the Yangtze River." Water 11, no. 2 (February 4, 2019): 269. http://dx.doi.org/10.3390/w11020269.

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The Three Gorges Project (TGP) is the largest hydroelectric project in the world. It is crucial to understand the relationship between runoff regime changes and TGP’s full operation after 2009 in the Yangtze River Basin (YRB). This paper defines core, extended and buffer areas of YRB, analyzes the effects of TGP on runoff anomaly (RA), runoff variation (RV) and change of coefficient of variation (CCV) between two periods (2003–2008 and 2009–2016), takes percentage of runoff anomaly (PRA) as the evaluation standard, assures alleviation effect on severe dry and wet years of the research area, and finally summarizes related benefits of flood control from TGP. Our results indicate the inter-annual fluctuation of runoff in the core and extended areas expanded, but reduced in the buffer areas, and the frequencies of severe dry and wet years alleviated in the buffer, core and extended areas. Generally, the extended and core areas become less wet, and the buffer areas become less dry. The RV and CCV are both strengthened in the extended and core areas, but are weakened in the buffer areas, and RV is well positively correlated (R2 = 0.80) to CCV. Furthermore, the main benefits of TGP on flood control are remarkable in the reduction of disaster affected population, the decrease of agricultural disaster-damaged area, and the decline of direct economic loss. However, due to torrentially seasonal and non-seasonal precipitation, the sharp rebounds of three standards for Hubei and Anhui occurred in 2010 and 2016, and the percentage of agricultural damage area of five regions in the core and extended areas did not decline synchronously and performed irregularly. Our results suggest that the five key regions along the main branches of the Yangtze River should establish a flood control system and promote the connectivity of infrastructures at different levels to meet the significant functions of TGP. It is a great challenge for TGP operation to balance the benefits and conflicts among flood control, power generation and water resources supply in the future.

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Wang, Ping, Ankie Piters, Jos van Geffen, Olaf Tuinder, Piet Stammes, and Stefan Kinne. "Shipborne MAX-DOAS measurements for validation of TROPOMI NO2 products." Atmospheric Measurement Techniques 13, no. 3 (March 30, 2020): 1413–26. http://dx.doi.org/10.5194/amt-13-1413-2020.

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Abstract. Tropospheric NO2 and stratospheric NO2 vertical column densities are important TROPOspheric Monitoring Instrument (TROPOMI) data products. In order to validate the TROPOMI NO2 products, KNMI Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) instruments have measured NO2 on ship cruises over the Atlantic and the Pacific oceans. The MAX-DOAS instruments have participated in five cruises on board RV Sonne (in 2017 and 2019) and RV Maria S. Merian (in 2018). The MAX-DOAS measurements were acquired over 7 months and spanned about 90∘ in latitude and 300∘ in longitude. During the cruises aerosol measurements from Microtops sun photometers were also taken. The MAX-DOAS measured stratospheric NO2 columns between 1.5×1015 and 3.5×1015 molec cm−2 and tropospheric NO2 up to 0.6×1015 molec cm−2. The MAX-DOAS stratospheric NO2 vertical column densities have been compared with TROPOMI stratospheric NO2 vertical column densities and the stratospheric NO2 vertical column densities simulated by the global chemistry Transport Model, version 5, Massively Parallel model (TM5-MP). Good correlation is found between the MAX-DOAS and TROPOMI and TM5 stratospheric NO2 vertical column densities, with a correlation coefficient of 0.93 or larger. The TROPOMI and TM5 stratospheric NO2 vertical column densities are about 0.4×1015 molec cm−2 (19 %) higher than the MAX-DOAS measurements. The TROPOMI tropospheric NO2 also has good agreement with the MAX-DOAS measurements. The tropospheric NO2 vertical column density is as low as 0.5×1015 molec cm−2 over remote oceans.

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Kahnert, Kathrin, Bertram Jobst, Frank Biertz, Jürgen Biederer, Henrik Watz, Rudolf M. Huber, Jürgen Behr, et al. "Relationship of spirometric, body plethysmographic, and diffusing capacity parameters to emphysema scores derived from CT scans." Chronic Respiratory Disease 16 (May 9, 2018): 147997231877542. http://dx.doi.org/10.1177/1479972318775423.

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Phenotyping of chronic obstructive pulmonary disease (COPD) with computed tomography (CT) is used to distinguish between emphysema- and airway-dominated type. The phenotype is reflected in correlations with lung function measures. Among these, the relative value of body plethysmography has not been quantified. We addressed this question using CT scans retrospectively collected from clinical routine in a large COPD cohort. Three hundred and thirty five patients with baseline data of the German COPD cohort COPD and Systemic Consequences-Comorbidities Network were included. CT scans were primarily evaluated using a qualitative binary emphysema score. The binary score was positive for emphysema in 52.5% of patients, and there were significant differences between the positive/negative groups regarding forced expiratory volume in 1 second (FEV1), FEV1/forced vital capacity (FVC), intrathoracic gas volume (ITGV), residual volume (RV), specific airway resistance (sRaw), transfer coefficient (KCO), transfer factor for carbon monoxide (TLCO), age, pack-years, and body mass index (BMI). Stepwise discriminant analyses revealed the combination of FEV1/FVC, RV, sRaw, and KCO to be significantly related to the binary emphysema score. The additional positive predictive value of body plethysmography, however, was only slightly higher than that of the conventional combination of spirometry and diffusing capacity, which if taken alone also achieved high predictive values, in contrast to body plethysmography. The additional information on the presence of CT-diagnosed emphysema as conferred by body plethysmography appeared to be minor compared to the well-known combination of spirometry and CO diffusing capacity.

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Selig, W. M., T. C. Noonan, D. F. Kern, and A. B. Malik. "Pulmonary microvascular responses to arachidonic acid in isolated perfused guinea pig lung." Journal of Applied Physiology 60, no. 6 (June 1, 1986): 1972–79. http://dx.doi.org/10.1152/jappl.1986.60.6.1972.

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We examined the effects of arachidonic acid (AA) on pulmonary hemodynamics and fluid balance in Ringer- and blood-perfused guinea pig lungs during constant-flow conditions. Mean pulmonary arterial (Ppa), venous (Pv), and capillary pressures (Pcap, estimated by the double-occlusion method) were measured, and arterial (Ra) and venous resistances (Rv) were calculated. Bolus AA injection (500 micrograms) caused transient increases (peak response 1 min post-AA) in Ppa, Pcap, and Rv without affecting Ra in both Ringer- and blood-perfused lungs. The response was sustained in blood-perfused lungs. AA had no effect on the capillary filtration coefficient in either Ringer- or blood-perfused lungs. AA stimulated the release of thromboxane B2 and 6-ketoprostaglandin F1 alpha in both Ringer- and blood-perfused lungs, but the responses were sustained only in the blood-perfused lungs. Meclofenamate (1.5 X 10(-4) M), a cyclooxygenase inhibitor, abolished the AA-induced pulmonary hemodynamic responses in both Ringer- and blood-perfused lungs, whereas U-60257 (10 microM), a lipoxygenase inhibitor, attenuated the response only in the blood-perfused lungs. In conclusion, AA does not alter pulmonary vascular permeability to water in either Ringer- or blood-perfused lungs. AA mediates pulmonary venoconstriction and thus contributes to the rise in Pcap. The venoconstriction results from the generation of cyclooxygenase-derived metabolites from lung parenchymal cells and blood-formed elements. Lipoxygenase metabolites may also contribute to the vasoconstriction in the blood-perfused lungs.

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Pajtášová, Mariana, Zuzana Mičicová, Darina Ondrušová, Slavomíra Božeková, Róbert Janík, Beáta Pecušová, and Lukáš Raník. "Use of waste materials in rubber matrix." MATEC Web of Conferences 157 (2018): 07009. http://dx.doi.org/10.1051/matecconf/201815707009.

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The presented paper deals with the use of waste materials as ecological fillers into rubber matrix. Waste materials were used as partial replacement of the commercial filler – carbon black, designated as N339. These prepared rubber compounds were characterized on the basis of the rheology and vulcanization characteristics – minimum torque (ML), maximum torque (MH), optimum time of vulcanization (t(c90)), processing safety of compound (ts), rate coefficient of vulcanization (Rv). In the case of the prepared vulcanizates, physical-mechanical properties (tensile strength, tensibility and hardness) and dynamic-mechanical properties (storage modulus, loss modulus, loss angle tan δ) were investigated. Using the dependency of loss angle on temperature, the selected properties for tyre tread vulcanizates were evaluated, including traction on snow and ice, traction on the wet surface and rolling resistance.

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Journal articles on the topic 'RV coefficient'

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