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Rcapture: Loglinear Models for Capture-Recapture in R
This article introduces Rcapture, an R package for capture-recapture experiments. The data for analysis consists of the frequencies of the observable capture histories over the t capture occasions of the experiment. A capture history is a vector of zeros and ones where one stands for a capture and zero for a miss. Rcapture can fit three types of models. With a closed population model, the goal of the analysis is to estimate the size N of the population which is assumed to be constant throughout the experiment. The estimator depends on the way in which the capture probabilities of the animals vary. Rcapture features several models for these capture probabilities that lead to different estimators for N. In an open population model, immigration and death occur between sampling periods. The estimation of survival rates is of primary interest. Rcapture can fit the basic Cormack-Jolly-Seber and Jolly-Seber model to such data. The third type of models fitted by Rcapture are robust design models. It features two levels of sampling; closed population models apply within primary periods and an open population model applies between periods. Most models in Rcapture have a loglinear form; they are fitted by carrying out a Poisson regression with the R function glm. Estimates of the demographic parameters of interest are derived from the loglinear parameter estimates; their variances are obtained by linearization. The novel feature of this package is the provision of several new options for modeling capture probabilities heterogeneity between animals in both closed population models and the primary periods of a robust design. It also implements many of the techniques developed by R. M. Cormack for open population models.
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Testing Drugs and Attesting Cures: Pharmaceutical Monopolies and Military Contracts in Eighteenth-Century France.
This article explores the role of testing in the allocation of royal monopoly privileges for drugs in eighteenth-century France by following the multi-generational fortunes of a single "secret remedy" from 1713 to 1776: the poudre fébrifuge of the Chevalier de Guiller. On at least five occasions, this drug was tested on patients in order to decide whether it should be protected by a privilege and whether or not its vendors should be awarded lucrative contracts to supply it in bulk to the French military. Although efforts were made early in the century to test the drug through large-scale hospital trials and to relegate privilege granting to a bureaucratic commission, the case of the poudre fébrifuge instead suggests that military expediency and relatively small-scale trials administered personally by royal practitioners remained decisive in determining whether or not a drug received a monopoly privilege or a military contract
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