Pubertal Development, Choice of Friends, and Smoking Initiation among Adolescent Males

Prior research has indicated that pubertal development and peer associations are important determinants of adolescent smoking behavior. However, more remains to be learned about why these variables matter or how they may be related to one another in ways that lead to the initiation of smoking. Using contractual data from the National Longitudinal Study of Adolescent Health, we consider the relationship between early pubertal development and associations with close friends who smoke, and smoking initiation among male youths. The results of the study reveal a link between advanced pubertal development and the initiation of smoking among boys, but we discover that the effect is indirect, mediated by a greater propensity of sexually mature males to forge friendships with peers who smoke. We also find that this propensity is greatest among the youngest adolescents in the sample, suggesting that the age of the respondent conditions the effects of pubertal development on the formation of friendships with peers who smoke.(Ph.D., The University of Texas at Austin), is an Assistant Professor at Washington State University at Vancouver. Her areas of interest include juvenile delinquency and substance abuse.(Ph.D., Rutgers: The State University of New Jersey) is an Assistant Professor at Westfield State College. Her area of interest is adolescent identity development.(Ph.D., The University of Texas at Austin) is an Associate Professor at the University of Portland. His areas of interest include biosocial models of adolescent problem behavior.     

Monotone Comparative Statics for Models of Politics

We elucidate a powerful yet simple method for deriving comparative statics conclusions for a wide variety of models: Monotone Comparative Statics ( Milgrom and Shannon 1994 ). Monotone comparative static methods allow researchers to extract robust, substantive empirical implications from formal models that can be tested using ordinal data and simple nonparametric tests. When these methods apply, they can replace a diverse range of more technically difficult mathematics (facilitating richer, more realistic models), assumptions that are hard to understand or justify substantively (highlighting the political intuitions underlying a model's results), and a complicated set of methods for extracting implications from models. We present an accessible introduction to the central monotone comparative statics results and a series of practical tools for using these techniques in applied models (with reference to original sources, when relevant). Throughout we demonstrate the techniques with examples drawn from political science .     

Nomenklatura,state monopoly,and private enterprise

Using a behavioral model of political decisionmaking, it is argued that an increasing population size and/or an increasing efficiency of production in a private enterprise economy relative to a centrally planned economy may create the conditions for a self-interested nomenklatura in a Soviet-type economy to consider a transition to a market economy. This transition may be thwarted, however, by the threat for prospective private enterpreneurs of exploitation after the change of regime. Some form of political pluralism guaranteeing sufficient political influence to private entrepreneurs appears to be required for a successful transition. The analysis shows that such a combined political and economic reform can be in the interest of the nomenklatura, thereby providing an endogenous behavioral explanation for a change of regime.     

Selenium determination in mother and child's hair by electrothermal atomic absorption spectrometry

A method for the selenium determination in a mother and her child's hair using palladium as a chemical modifier was optimized. The sample was digested with nitric acid and hydrogen peroxide and diluted to 5 ml. To achieve complete mineralization the samples were ashed at 1200 degrees C in the presence of palladium as a chemical modifier. The optimum atomization temperature was 1900 degrees C. The precision and accuracy of the method were studied using the reference material CRM 397. Results of calibration using aqueous standards and the standard addition method were compared. The method was applied to the selenium determination in 30 samples of the mother's and child's hair. The levels found were 0.54 +/- 0.34 microgram/g for mother's hair and 0.77 +/- 0.25 microgram/g for child's hair.     

DNA typing: an accessory evidence in doping control

A clear positive case for anabolic steroids doping was confounded by alleged urine tampering during doping control procedures. Review of the chain of custody showed no flaws, but nevertheless the athlete was adamant that the urine sample should be analyzed for DNA in order to support her contention that she was not the donor of the sample. The results obtained showed that the urine sample that scored positive for steroids contained nuclear DNA that could not be matched to the DNA obtained from the athlete's blood. On the other hand, the same urine sample contained mitochondrial DNA whose nucleotide sequences spanning the hyper variable regions HV1 and HV2 proved to be identical to those determined in mitochondrial DNA amplified from the athlete's blood. The occurrence of an extraneous genotype is compatible with exogenous nuclear DNA admixture to the athlete's urine. Alternatively, taking in consideration the mitochondrial DNA, we could not exclude that a sibling or a maternal relative of the athlete could have acted as a donor of the urine utilized for doping control and DNA analysis. Both situations point to possible tampering of the urine by the athlete. Adjudication at CAS maintained previous national and international federation decision that there was no proof of a chain of custody flaw to justify the athlete's allegation of urine substitution after collection.