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Many, if not most, drug abuse counselors and treatment programs recommend abstinence from all psychoactive substances, in part, because of a fear that clients who decrease or stop their use of one drug will substitute another. Research to confirm this notion of substitution, however, mostly fails to show that abstinence from one drug increases use of another. A within-subjects study investigated whether consumption of alcohol and other substances changed during marijuana abstinence. Using an ABA design, 28 individuals who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSMIV; American Psychiatric Association [APA], 2000) criteria for either cannabis dependence or abuse and were not trying to stop their marijuana use completed an 8-day baseline period in which they used marijuana and other drugs as usual, then a 13-day marijuana abstinence period, and finally a 7-day return-to-baseline period. Marijuana abstinence was induced by a previously-validated contingent compensation schedule. Participants called a voicemail system daily to provide self-report of marijuana and alcohol use and visited the laboratory twice per week to provide self-report of caffeine, cigarette, and other illicit drug use, to complete self-report measures on psychological symptoms such as withdrawal and craving, and to submit urine samples to biochemically verify marijuana abstinence. Alcohol use significantly increased from a mean of 2.6 drinks/day (SD=1.0) during the baseline period to 3.0 drinks/day (SD=1.0) during the marijuana abstinence period (p=0.03), a 15% increase. Alcohol use then significantly decreased to 2.5 drinks/day (SD=1.3) during the return-to-baseline period (p=0.03), a 17% decrease. Although alcohol substitution occurred during marijuana abstinence, substitution of cigarettes, caffeine, and non-marijuana illicit drugs did not occur. Individuals with a diagnosis of past alcohol abuse or dependence substituted alcohol to a greater degree (52% increase) than those without this past history (3% increase). Increases in alcohol drinks/day correlated with increases in marijuana withdrawal discomfort scores and with increases in alcohol craving scores from the baseline to the marijuana abstinence period. Problems related to alcohol did not significantly increase from baseline to marijuana abstinence. This study provides empirical validation of the clinical notion of drug substitution and suggests that clinicians’ concerns about drug substitution may be valid, but this study’s results need to be replicated in individuals who seek treatment for marijuana problems. Whether substitution reduces the ability to abstain from marijuana also needs to be tested. If alcohol substitution does occur and interferes with the ability to quit marijuana, this would be important empirical support for the clinical practice of recommending abstinence from all substances.

L’objectif de ce travail était de mesurer l’effet de différentes essences sur un sol acide. Le milieu a été caractérisé par une analyse minéralogique approfondie de la roche et du sol. Cette étude a été réalisée sur le site expérimental de Breuil (Morvan) mis en place en 1976. Les essences étudiées sont : la forêt native constituée par un Taillis-sous-Futaie (TsF) feuillu, le chêne, le hêtre, l’épicéa commun, le Douglas, le sapin de Nordmann et le pin laricio. Plusieurs études ont été menées à différentes échelles pour caractériser l’effet des essences sur le sol avec la détermination : i) des propriétés physico-chimiques la terre fine ii) de la minéralogie des fractions fines iii) du fonctionnement actuel des sols par incubation de vermiculites-test iv) des propriétés physico-chimiques et minéralogiques du sol rhizosphérique. Les résultats indiquent que le sol est acide et très pauvre en cations alcalino-terreux. Comparativement aux feuillus, les résineux provoquent une désaturation et une acidification du complexe d’échange de ce sol selon l’ordre suivant : épicéa = Pin = Douglas > TsF =chêne = hêtre. L’étude des fractions granulométriques fines montre que le Douglas et le pin provoquent une dissolution nettement plus importante de certaines phases argileuses que l’épicéa et les feuillus. L’altération des minéraux est plus poussée dans le sol rhizosphérique que dans le sol global, notamment sous épicéa. Les modifications observées sur la phase solide du sol sont interprétées de manière satisfaisante par l’intégration des propriétés du cycle biogéochimique propre à chaque essence. Cette étude apporte des connaissances importantes pour les aménagistes forestiers. / The aim of this work was to measure the effect of different forest species on the same acid soil and its mineralogy. The site was described in detail by studying the parent material and a soil profile. The study was carried out at Breuil Experimental Site in Morvan, France, which was set up in 1976. The species studied were: native forest species in a broad-leaved Coppice with Standards (CwS), oak, beech, Norway spruce, Douglas fir, Nordmann fir and Corsican Laricio pine. Several methods were used: i) the physico-chemical properties of the fine earth; ii) the mineralogy of the fine soil fractions; iii) the present functioning of the soil using vermiculite placed in situ in the soil as a test-mineral, in parallel with a dissolution experiment on the same mineral in a controlled environment; and iv) the physico-chemical and mineralogical properties of the rhizospheric soil under oak and spruce. The results indicated that the granite was acid and very poor in basic cations. In comparison with the broad-leaved trees, the conifers caused additional desaturation and acidification of the exchange complex of this soil. Examination of the clay fraction showed that Douglas fir and pine caused a much greater dissolution of certain clay mineral phases than the spruce and broad-leaved trees. Mineral weathering was also greater in the rhizospheric soil, than in the total soil, especially below spruce which was related to the ammoniacal form of nitrogen nutrition. Changes observed in the solid soil phase were satisfactorily explained by the integration of the properties of the bio-geo-chemical cycle of each species. This study provides interesting information relevant to forest managers.

Selective pressures at the DNA level shape genes into pro les consisting of patterns of rapidly evolving sites and sites withstanding change. These pro les remain detectable even when protein sequences become extensively diverged. It has been hypothesised that these patterns can be used as gene identi ers. A common task in molecular biology is to infer functional, structural or evolutionary relationships by querying a database using an algorithm. However, problems arise when sequence similarity is low. The problem is that the algorithm produces numerous false positives when highly conserved datasets are aligned. To increase the sensitivity of the algorithm, the evolutionary rate based approach was reimplemented and coupled with a conventional BLOSUM substitution matrix to produce a new implementation called BLOSUM-FIRE. The two approaches are combined in a dynamic scoring function, which uses the selective pressure to score aligned residues. Analysis of quality of alignments produced, revealed that the new implementation of the FIRE algorithm performs as well as conventional algorithms. In addition, the Evolutionary rate Database (EvoDB), which is a compilation of evolutionary rate pro les of all the members of the PFAM-A protein domain database has been developed. The EvoDB database can be queried using FIRE to infer protein domain functions. The utility of this algorithm and database was tested by inferring the domain functions of the Hepatitis B X protein. Results show that the BLOSUM-FIRE algorithm was able to accurately identify the domain function of HBx as a trans-activation protein using EvoDB. The biological relevance of these results was not validated and requires further interrogation; however, these proteins share vital roles in viral replication. This study demonstrates the utility of an evolutionary rate based approach and demonstrates that such an approach is robust when coupled with an amino acid substitution matrix yielding results comparable to conventional algorithms. EvoDB is a catalogue of the evolutionary rate pro les and provides the corresponding phylogenetic trees, PFAM-A alignments and annotated accession identi er data. The BLOSUM-FIRE software and user manual including the EvoDB at le database and release notes have been made freely available at www.bioinf.wits.ac.za/software/fire. The BLOSUM-FIRE algorithm and EvoDB database present a tier of information untapped by current databases and tools. / A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in ful lment of the requirements of the degree of Master of Science (Medicine).

Vita. / Digitized by Kansas Correctional Industries

Includes bibliographical references. / 381 p. ; / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / A comprehensive study into the design, understanding and utilisation of free-radical homolytic substitution chemistry / Thesis (D.Sc.)--University of Adelaide, Dept. of Chemistry, 2000?

Thesis (M. Sc.)--University of Hong Kong, 1971. / Mimeographed.