What Makes Chilean Agriculture Tick? Estimation and Interpretation of Elasticities in Representative Markets
The Chilean countryside has experienced dramatic change in the last 20 years. From the mid-1960s onwards successive governments implemented increasingly radical land reforms. This process was stopped by the 1973 military coup, after which some land was returned to the original owners and most of it distributed in individual parcels. Later on some concentration occurred, resulting mainly from small farmers being forced to sell by lack of credit and technical support. But the age-old traditional large estates (described by some authors as pre-capitalist latifundia or haciendas) were not reestablished; instead new family-sized and modern capitalist farms developed. At the same time, the post-1973 macroeconomic policies liberalised external trade and domestic prices, and agricultural exports and imports rose. The traditional patterns of land exploitation, labour use and rural-urban migration all experienced substantive change (Rivera and Cruz, 1984; Kay, 1985).
Assertion without empirical basis: an econometric appraisal of monetary trends in... the United Kingdom, by Milton Friedman and Anna J. Schwartz
This paper critically re-evaluates some of the fundamental empirical claims about monetary behavior in the United Kingdom made by Milton Friedman and Anna J. Schwartz in their 1982 book Monetary Trends in the United States and the United Kingdom. We focus on six aspects of their analysis: the exogeneity of money; their claims of the constancy and correct specification of their money-demand equation; their interpretation of a dummy variable in that equation as capturing a "shift in liquidity preference" for 1921-55; their treatment of the interdependence of money, income, prices, and interest rates; and their use of phase-average data. They fail to support many of their empirical assertions with valid econometric evidence: in particular, they leave untested many conditions necessary to sustain their inferences. However, those conditions either are in part directly testable from their data or have testable implications: we test many of those hypotheses and reject virtually all of them. We reject basic claims made for their empirical model of money demand, e.g., those of parameter constancy, price homogeneity, and normality of the disturbances. En route, we show that their model of velocity as a constant performs poorly relative to the "will-o'-the-wisp" model of velocity as a random walk. As constructive evidence against their models, we develop a money-demand model superior to either model of velocity, and which has an unexplained residual variance less than one tenth that of their money-demand equation. This paper, however, is not an "anti-monetarist" critique; rather, it is a pro-econometrics tract which highlights the practical dangers of seeking to analyze complex stochastic processes while eschewing modern econometric methods.
Pharmacokinetics of Mivacurium Isomers and Their Metabolites in Healthy Volunteers after Intravenous Bolus Administration
Background Previous studies report the pharmacokinetics of mivacurium isomers after an infusion using venous blood sampling. Although the extent of the mivacurium arterial‐venous gradient is not known, the sampling site is likely to influence mivacurium pharmacokinetic parameters because the drug is rapidly metabolized as it traverses the circulation. The objectives of this study were (1) to determine the pharmacokinetics of mivacurium isomers in healthy persons after intravenous bolus administration using intensive arterial blood sampling, and (2) to characterize the formation and elimination of mivacurium metabolites in human plasma. Methods Eight persons classified as American Society of Anesthesiologists physical status 1 or 2 who were scheduled to undergo elective surgery under balanced anesthesia received 0.15 mg/kg mivacurium chloride as an intravenous bolus. Arterial blood samples were collected every 10 s during the first 2 min and at frequent intervals for 4 h thereafter. Plasma concentrations of mivacurium isomers and their metabolites were determined by two stereoselective high‐performance liquid chromatographic methods coupled with fluorometric detection and noncompartmental pharmacokinetic parameters. Results Mean elimination half‐lives of the trans‐trans, cis‐trans, and cis‐cis isomers were 2.4, 2, and 28.5 min, respectively, with corresponding mean plasma clearances of 29.2, 45.7, and 6.7 ml [center dot] min‐1 [center dot] kg‐1. The volumes of distribution at steady state of the trans‐trans, cis‐trans, and cis‐cis isomers were 0.047, 0.054, and 0.189 l/kg, respectively. Plasma concentrations of monoester and alcohol metabolites peaked 25 s (median) after mivacurium injection, with half‐lives in the range of 90 min, except for the cis alcohol metabolite, which was only negligibly and transiently formed. Conclusions Substantial hydrolysis of mivacurium isomers by cholinesterases was confirmed by the rapid appearance of mivacurium metabolites in plasma. The intensive arterial sampling proved to be critical for the trans‐trans and cis‐trans isomers because the area under the curve between 0 and 2 min accounted for 75% and 86% of the total, respectively.