Modeling pan evaporation using Gaussian Process Regression, K-Nearest Neighbors, Random Forest, and Support Vector Machines: Comparative analysis

Evaporation is a very important process; it is one of the most critical factors in agricultural, hydrological, and meteorological studies. Due to the interactions of multiple climatic factors, evaporation is considered as a complex and nonlinear phenomenon to model. Thus, machine learning methods have gained popularity in this realm. In the present study, four machine learning methods of Gaussian Process Regression (GPR), K-Nearest Neighbors (KNN), Random Forest (RF) and Support Vector Regression (SVR) were used to predict the pan evaporation (PE). Meteorological data including PE, temperature (T), relative humidity (RH), wind speed (W), and sunny hours (S) collected from 2011 through 2017. The accuracy of the studied methods was determined using the statistical indices of Root Mean Squared Error (RMSE), correlation coefficient (R) and Mean Absolute Error (MAE). Furthermore, the Taylor charts utilized for evaluating the accuracy of the mentioned models. The results of this study showed that at Gonbad-e Kavus, Gorgan and Bandar Torkman stations, GPR with RMSE of 1.521 mm/day, 1.244 mm/day, and 1.254 mm/day, KNN with RMSE of 1.991 mm/day, 1.775 mm/day, and 1.577 mm/day, RF with RMSE of 1.614 mm/day, 1.337 mm/day, and 1.316 mm/day, and SVR with RMSE of 1.55 mm/day, 1.262 mm/day, and 1.275 mm/day had more appropriate performances in estimating PE values. It was found that GPR for Gonbad-e Kavus Station with input parameters of T, W and S and GPR for Gorgan and Bandar Torkmen stations with input parameters of T, RH, W and S had the most accurate predictions and were proposed for precise estimation of PE. The findings of the current study indicated that the PE values may be accurately estimated with few easily measured meteorological parameters

Increased Short-Term Beat-To-Beat Variability of QT Interval in Patients with Acromegaly.

Cardiovascular diseases, including ventricular arrhythmias are responsible for increased mortality in patients with acromegaly. Acromegaly may cause repolarization abnormalities such as QT prolongation and impairment of repolarization reserve enhancing liability to arrhythmia. The aim of this study was to determine the short-term beat-to-beat QT variability in patients with acromegaly. Thirty acromegalic patients (23 women and 7 men, mean age+/-SD: 55.7+/-10.4 years) were compared with age- and sex-matched volunteers (mean age 51.3+/-7.6 years). Cardiac repolarization parameters including frequency corrected QT interval, PQ and QRS intervals, duration of terminal part of T waves (Tpeak-Tend) and short-term variability of QT interval were evaluated. All acromegalic patients and controls underwent transthoracic echocardiographic examination. Autonomic function was assessed by means of five standard cardiovascular reflex tests. Comparison of the two groups revealed no significant differences in the conventional ECG parameters of repolarization (QT: 401.1+/-30.6 ms vs 389.3+/-16.5 ms, corrected QT interval: 430.1+/-18.6 ms vs 425.6+/-17.3 ms, QT dispersion: 38.2+/-13.2 ms vs 36.6+/-10.2 ms; acromegaly vs control, respectively). However, short-term beat-to-beat QT variability was significantly increased in acromegalic patients (4.23+/-1.03 ms vs 3.02+/-0.80, P<0.0001). There were significant differences between the two groups in the echocardiographic dimensions (left ventricular end diastolic diameter: 52.6+/-5.4 mm vs 48.0+/-3.9 mm, left ventricular end systolic diameter: 32.3+/-5.2 mm vs 29.1+/-4.4 mm, interventricular septum: 11.1+/-2.2 mm vs 8.8+/-0.7 mm, posterior wall of left ventricle: 10.8+/-1.4 mm vs 8.9+/-0.7 mm, P<0.05, respectively). Short-term beat-to-beat QT variability was elevated in patients with acromegaly in spite of unchanged conventional parameters of ventricular repolarization. This enhanced temporal QT variability may be an early indicator of increased liability to arrhythmia

Folyóirat-referátumok; Beszámolók; Kvíz

Folyóirat-referátumok: Laboratóriumi medicina: 1. R. K. Riezebos - G. J. Laarman - J. G. Tijssen [et al.]: Magas rizikójú, ST-elevációval nem járó akut coronariaszindrómás esetekben az N-terminális proBNP molekula alkalmazhatósága a korai szívizomelhalás felismerésére = The Value of N-terminal proB-type Natriuretic Peptide for Early Identification of Myocardial Infarction in Patients with High-risk Non-ST-Elevation Acute Coronary Syndromes Neurológia: 1. Chr. Campbell - H. Woessner - W. D. Freeman [et al.]: Összefüggés a hétvégi kórházi ellátás és a fatális szélütés között = Association Between Weekend Hospital Presentation and Stroke Fatality Beszámolók: 1. Az Osztrák Gyermek- és Ifjúsági Társaság 49. Kongresszusa = 49. Jahrestagung der ÖGKJ (Österreichischen Gesellschaft für Kinder- und Jugendheilkunde. Villach, 2011. október 6–8