BACKGROUND The restitution of the action potential duration (APDR) and conduction velocity (CVR) are mechanisms whereby cardiac excitation and repolarization adapt to changes in heart rate. They modulate the vulnerability to dangerous arrhythmia, but the mechanistic link between restitution and arrhythmogenesis remains only partially understood. METHODS This paper provides an experimental and...

Quantifying critical conditions of rill formation can be useful for a better understanding of soil erosion processes. Current studies lack a consensus and related rationale on how to describe these conditions. This study was based on the concepts that (1) the shear stress available for erosion at any given point is a function of the runoff rate, the slope steepness, and hydraulic characteristic...

Economic and environmental logging is important for sustainable wood production in the Caspian forests, north of Iran. Predetermination of the skid trail network and directional felling is a usual recommended method to reduce logging impact. The aim of this study was evaluation of directional felling and finding factors effective on felling error. Totally 135 trees were selected randomly for di...

We compare the effects of taxes and quotas for an environmental problem where the regulator and polluter have asymmetric information about abatement costs, and environmental damage depends on pollution stock. An increase in the slope of the marginal abatement cost curve, or a decrease in the slope of the marginal damage curve, favors taxes. An increase in the discount rate or the stock decay ra...

We examined the length changes and electromyographic (EMG) activity of two hindlimb muscles in wild turkeys, to determine how these muscles modulate mechanical function with changes in running speed and slope. The muscles studied were the iliotibialis lateralis pars postacetabularis (ILPO), a biarticular knee and hip extensor, and the femorotibialis lateralis (FT), a knee extensor. Muscle lengt...

Operational speed is an index that represents drivers’ speeding behaviors and shows the comfort and safety levels they experience. Many models had been proposed to predict operational speed in tangent and curve segments of highways. Most of these works had used geometric, with few of them conducted using roadside variables to predict operational speed. Also, the operational speed study in multi...

the rate of soil erosion and sediment yield estimation in the catchment areas is considered as an important factor for soil and water conservation practices. due to difficulties and restrictions in common soil erosion methods, applying a high accuracy method with lowest cost and time consuming would be necessary. assessment of soil loss in hilly areas with capacity of rang land that has changed...