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This study aims to evaluate the potential for potable water savings by modelling the hypothetical installation of a system that combines rainwater and greywater in a house. The system consists of using rainwater to wash clothes and then reusing the effluent to flush toilets. The potential for potable water savings and the tank capacity for rainwater storage were estimated using the computer programme Netuno. A financial analysis was performed. For a rainwater tank capacity equal to 5000 litres, it was possible to obtain 51.6% potable water savings. The payback period was estimated as five years and three months. The system combining rainwater and greywater is a good alternative to save potable water because there was a significant reduction in potable water consumption and low payback period. The high potable savings and low payback period found in this work may contribute to the acceptability of these technologies and practices. [ABSTRACT FROM AUTHOR]

Left atrium function is essential for cardiovascular performance and is evaluable by two-dimensional speckle-tracking echocardiography (2D-STE). Our aim was to determine how echocardiographic parameters interrelate with exercise capacity and ventilatory efficiency in subjects with no structural heart disease. Asymptomatic volunteers, in sinus rhythm and with normal biventricular size and function, were recruited from a community-based population. Individuals with moderate-to-severe valvular disease, pulmonary hypertension, and history of cardiac disease were excluded. We performed a transthoracic echocardiogram and assessed left atrial (LA) and left ventricular (LV) mechanics via 2D-STE. Cardiopulmonary exercise testing by treadmill took place immediately thereafter. Peak oxygen uptake (VO2) served as measure of functional capacity and ventilation/carbon dioxide output (VE/VCO2) slope as surrogate of ventilation/perfusion mismatch. 20 subjects were included (age 51 ± 14 years, male gender 65%). Peak VO2 strongly correlated with age (r = -0.83; P < 0.01), with E/e' ratio (r = -0.72; P < 0.01), and with LA reservoir- and conduit-phase mechanics, particularly with LA conduit strain rate (SR) (r = -0.82; P < 0.01), but showed no correlation with LA volume index or LV mechanics. A similar pattern of associations was identified for VE/VCO2 slope. In multivariate analysis, LA conduit SR (β = -0.69; P = 0.02) emerged as sole independent correlate of peak VO2, adjusted for age and for E/e' ratio (adjusted r 2  = 0.76; P < 0.01). Conduit and reservoir components of LA mechanics displayed strong associations with peak VO2 and VE/VCO2 slope. LA conduit-phase SR seems best suited as echocardiographic marker of functional capacity in subjects with no structural heart disease. [ABSTRACT FROM AUTHOR]