The primary goal of this study is to ascertain whether relapse to drug dependence, in terms of continuous abstinence assessment, exhibits a typical pattern that can be characterized by a common quantitative function. If the relapse curve is indeed ubiquitous, then some underlying mechanism must be operating to shape the curve that transcends variables such as drug class, population or treatment type. Survival analyses are performed on 20 alcohol and tobaccotreatment studies using the proportions of individuals remaining abstinent following a period of initial abstinence. Several parametric models of relapse are compared and the results demonstrate that a log-logistic distribution is the most accurate reflection of the available data and the basic shape of the relapse curve is uniform. In the vast majority of reports examined, the rate of relapse decelerates after initial abstinence has been achieved, and therefore the amount of accumulated time abstinent may be the transcending variable that operates to shape the relapse curve.

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The lampricide 3-trifluoromethyl-4-nitrophenol (TFM) is used to control sea lamprey (Petromyzon marinus) populations in freshwater lakes. While TFM can have sublethal and lethal effects, little is known about gene expression changes with TFM exposure. Microarray analysis was used to determine differential gene expression over 4 hours of exposure in S. cerevisiae. Among the most significantly up regulated genes were regulators of carbohydrate transport including HXT1, HXT3, HXT4, IMA5, MIG2, and YKR075C.

SynopsisIn standard treatments of calculus, the Fundamental Theorem of Calculus is often presented as a computational method to evaluate definite integrals, with such powerful utility that one is tempted to overlook its beauty. To improve students' appreciation for the first part of the Fundamental Theorem of Calculus, we suggest a few classroom examples focusing on the accumulation function, to be introduced early and often throughout an introductory calculus course. These examples are small enough that they would not necessarily result in changes to a typical course schedule; yet we believe their contribution to student understanding can be significant. Furthermore, such examples might allow students to share more of the excitement that the pioneers of the subject surely experienced along the way.