The north-central zone of Chile is described with respect to groundwater supply problems. In this region, groundwater is almost exclusively obtained from the thin alluvium in the main transverse valleys, which descend from the Andes in those sections where the valleys cross the northerly trending "central valley." Because of the steep groundwater gradients prevailing, the groundwater resources ...

A multidisciplinary investigation was carried out in a karstic depression housing development under construction Madrid to assess its stability. It found that it is small basin within larger as result of subsidence accumulated during the Quaternary. Subsidence has built up progressively Miocene clay cap and bedrock due underlying dissolution gypsum rich intercalations. The preferential circulat...

A 45-year-old woman underwent an electrophysiology procedure because of a 20-year history of recunent episodes of paroxysmal tachycardia. The baseline sinus cycle length, atrial-His. and His-ventricular intervals were 700, 60, and 45 msec, respectively, and the QRS duration was 80 msec. Ventricular pacing at a cycle length of 300 msec induced a tachycardia that had a cycle length of 320 msec an...

The purpose of this study was to determine left ventricular activation, dispersion of refractoriness, and total recovery time in patients with coronary artery disease and ventricular tachycardia and in patients with the long QT syndrome and to compare these patients with a group of normal patients. Left ventricular endocardial catheter mapping and left ventricular refractory period determinatio...

background: the right ventricular (rv) dyssynchrony has not been studied extensively and the existing literature has established the effect of cardiac resynchronization therapy (crt) on the left ventricular (lv) dyssynchrony, but there is a dearth of data on the effect of crt on the forgotten ventricle . we sought to evaluate the presence of mechanical right ventricular dyssynchrony in patients...

To evaluate the direct electrophysiologic effects of i.v. disopyramide phosphate and to differentiate these effects from its autonomically mediated actions, we administered the drug (2 mg/kg over 5 minutes) during electrophysiologic study to eight cardiac transplant recipients who had documented functional cardiac denervation. After disopyramide, the cycle length of the denervated donor right a...

Two-dimensional sum-of-sines waveforms were pursued by the eye with very small phase delays compared with visual feedback delays estimated in the same monkeys. Processing delays in making smooth corrections averaged 90 msec after infrequent right-angle perturbations from a circular trajectory. These feedback delays were much larger than component phase delays during pursuit that averaged: 10 ms...

We examined the reflex change in refractory period (RP) of the left ventricle produced by stimulation of the central end of the caudovagal nerve (CVS). RP was recorded in the region of distribution of the left anterior descending coronary artery. During the determination of RP, hearts were paced at cycle lengths between 244 and 315 msec. Initially, the tonic effects of removing vagal and sympat...