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The indiscriminate increase in impervious surface area, mainly associated with anthropogenic activities, is causing important environmental changes. Given the relevance of impervious surface area, this paper introduces an approach designed to map impervious areas. The proposed method was applied to the State of São Paulo, southern Brazil, using nighttime light imagery collected by the Visible Infrared Imaging Radiometer Suite Day–Night Band from the Suomi National Polar-orbiting Partnership satellite. Our hypothesis is that impervious surface area is primarily related to the presence of persistent nighttime light in space and time, and that its quantification basically depends on the brightness pattern emitted by the urban surface. Thus, brightness patterns extracted from monthly composites of nighttime light were associated with impervious surface area established through a random forest regression model. The results for the entire study area (248,000 km2) showed that the method was quite effective in predicting impervious surface area (R2= 0.90, p< 0.001), although, on average, an underestimation deviation (~ 20%) occurred. Focusing on densely urbanized areas, on the other hand, an overestimation error was reported, mainly around downtown areas. Despite this error, graduated values of impervious surface area were found in intra-urban spaces, making it possible to characterize, consistently, differences in the land-use patterns.

The effect of amiodarone on oral and intravenous pharmacokinetics of digoxin was studied in healthy volunteers. A single 0.5-mg dose of digoxin was administered orally to three subjects both before and after 2 weeks of oral amiodarone (200 mg daily), while three subjects received a 0.5-mg intravenous dose of the glycoside under the same experimental conditions. Two other subjects were given both oral and intravenous doses of digoxin at different times, in the absence and in the presence of amiodarone. After oral digoxin treatment, amiodarone increased peak serum concentration, total area under the serum concentration-time curve (AUC), and 5-day urinary recovery of the glycoside, without changes in peak time and absorption rate constant. During the intravenous study, no significant change occurred in AUC and urinary recovery after amiodarone administration. Absolute bioavailability, for the two subjects who received both oral and intravenous digoxin, increased by 36 and 43, respectively, after amiodarone treatment. Bioavailability derived from the mean values of oral and intravenous AUCs was 33 greater with amiodarone treatment. Apparent volume of distribution and systemic, extrarenal, and renal clearances of oral digoxin were not modified by amiodarone, when corrected for the bioavailability factor. Amiodarone had no effect on these pharmacokinetic parameters during the intravenous study with the glycoside. Our data indicate that increased oral bioavailability is the most relevant change in digoxin pharmacokinetics during the interaction with amiodarone and this can account for the increase in the glycoside concentrations.