Swarnadeep Sen

Aims: The purpose of this study was to determine the association between the nicotine metabolic rate and smoking behavior, including addiction, in adolescent smokers. Design: Baseline data from a prospective study of adolescent smoking behaviors and nicotine metabolism. Setting: The setting was an out-patient university hospital in San Francisco. Participants: Adolescent smokers aged 13-17 years old. Measurements: Participants completed self-report measures of smoking behavior and nicotine dependence. The nicotine metabolite ratio, a phenotypic marker of the rate of nicotine metabolism, was calculated using the ratio of concentrations of deuterium-labeled 3′-hydroxycotinine to cotinine-d4. Findings: Participants reported smoking a mean of 2.86 cigarettes per day [median=1.78, standard deviation =3.35] for 1.37 years. Results from multivariate analyses accounting for age, race/ethnicity, gender and duration of smoking indicated that slower metabolizers smoked more CPD than faster metabolizers. Slower metabolizers also showed greater dependence on the mFTQ. Conclusions: In adolescence, slower clearance of nicotine may be associated with greater levels of addiction, perhaps mediated by a greater number of cigarettes smoked. © 2012 The Authors, Addiction © 2012 Society for the Study of Addiction.

In this paper a theoretical model for measuring consciousness based on experimental observations is proposed. Consciousness, the awareness of one's self and one's immediate environment, is defined, in this paper, in terms of the information about this awareness that is contained in or being processed by the brain. This particular information content in the brain is extracted from the correlation functions of brain waves observed in EEG measurements at N points by determining an observation-based special time-dependent probability function, PN and Shannon's information theory formula. It is shown how PN provides information about awareness contained in the ensemble of brain waves. Consciousness is defined either directly by a formula, C, that depends on PN and represents the information contained in brain waves at time t, or its time derivate, D, that represents the rate at which this information is being processed. These measures are not localized; they do not depend on a single, immutable, hardwired detail of the brain but they do reflect subjective experiences, encoded by any one of a number of possible hardwired circuits. They are not clinical tools for measuring consciousness but rather represent ways to extract the information content of the brain from experimental measurements. Justifications, based on observational evidence, are given for the formulas presented.