86 resultados para Occasional speeches

em Université de Lausanne, Switzerland


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Many studies based on either an experimental or an epidemiological approach, have shown that the ability to drive is impaired when the driver is under the influence of cannabis. Baseline performances of heavy users remain impaired even after several weeks of abstinence. Symptoms of cannabis abuse and dependence are generally considered incompatible with safe driving. Recently, it has been shown that traffic safety can be increased by reporting the long-term unfit drivers to the driver licensing authorities and referring the cases for further medical assessment. Evaluation of the frequency of cannabis use is a prerequisite for a reliable medical assessment of the fitness to drive. In a previous paper we advocated the use of two thresholds based on 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) concentration in whole blood to help to distinguish occasional cannabis users (≤3μg/L) from heavy regular smokers (≥40μg/L). These criteria were established on the basis of results obtained in a controlled cannabis smoking study with placebo, carried out with two groups of young male volunteers; the first group was characterized by a heavy use (≥10 joints/month) while the second group was made up of occasional users smoking at most 1 joint/week. However, to date, these cutoffs have not been adequately assessed under real conditions. Their validity can now be evaluated and confirmed with 146 traffic offenders' real cases in which the whole blood cannabinoid concentrations and the frequency of cannabis use are known. The two thresholds were not challenged by the presence of ethanol (40% of cases) and of other therapeutic and illegal drugs (24%). Thus, we propose the following procedure that can be very useful in the Swiss context but also in other countries with similar traffic policies: if the whole blood THCCOOH concentration is higher than 40μg/L, traffic offenders must be directed first and foremost toward medical assessment of their fitness to drive. This evaluation is not recommended if the THCCOOH concentration is lower than 3μg/L and if the self-rated frequency of cannabis use is less than 1 time/week. A THCCOOH level between these two thresholds cannot be reliably interpreted. In such a case, further medical assessment and follow-up of the fitness to drive are also suggested, but with lower priority.

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A questionnaire investigating adolescents' opinions and experiences regarding marijuana use was administered to 163 adolescents and young adults (96 boys and 67 girls) aged 13 to 20 (mean age = 16.8, s.d. = 1.5). Items referred to marijuana and other substances' dangerousness, representations regarding the positive and negative consequences of marijuana use. Responses were compared according to marijuana use status (classified into never/occasional use, current regular use and past regular use). Results show that adolescents' opinions differ according to their experience with marijuana use. Current regular users evaluate marijuana as less dangerous, but alcohol and heroin as more dangerous in comparison with never/occasional and past users. Current and past users are more likely to define marijuana as a medical drug and a plant used in agriculture, and less likely to define it as an illegal drug. Current and past users evaluate marijuana use as a way to cope with stress, to relax to a greater extent than do never/occasional users do. The latter attribute more negative consequences to marijuana use such as diminished driving ability and school performance and a pathway to hard drugs.

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Objectives: Our aim was to study the brain regions involved in a divided attention tracking task related to driving in occasional cannabis smokers. In addition we assessed the relationship between THC levels in whole blood and changes in brain activity, behavioural and psychomotor performances. Methods: Twenty-one smokers participated to two independent cross-over fMRI experiments before and after smoking cannabis and a placebo. The paradigm was based on a visuo-motor tracking task, alternating active tracking blocks with passive tracking viewing and rest condition. Half of the active tracking conditions included randomly presented traffic lights as distractors. Blood samples were taken at regular intervals to determine the time-profiles of the major cannabinoids. Their levels during the fMRI experiments were interpolated from concentrations measured by GCMS/ MS just before and after brain imaging. Results: Behavioural data, such as the discard between target and cursor, the time of correct tracking and the reaction time during traffic lights appearance showed a statistical significant impairment of subject s skills due to THC intoxication. Highest THC blood concentrations were measured soon after smoking and ranged between 28.8 and 167.9 ng/ml. These concentrations reached values of a few ng/ml during the fMRI. fMRI results pointed out that under the effect of THC, high order visual areas (V3d) and Intraparietal sulcus (IPS) showed an higher activation compared to the control condition. The opposite comparison showed a decrease of activation during the THC condition in the anterior cingulate gyrus and orbitofrontal areas. In these locations, the BOLD showed a negative correlation with the THC level. Conclusion: Acute cannabis smoking significantly impairs performances and brain activity during active tracking tasks, partly reorganizing the recruitment of brain areas of the attention network. Neural activity in the anterior cingulate might be responsible of the changes in the cognitive controls required in our divided attention task.

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Some forensic and clinical circumstances require knowledge of the frequency of drug use. Care of the patient, administrative, and legal consequences will be different if the subject is a regular or an occasional cannabis smoker. To this end, 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) has been proposed as a criterion to help to distinguish between these two groups of users. However, to date this indicator has not been adequately assessed under experimental conditions. We carried out a controlled administration study of smoked cannabis with a placebo. Cannabinoid levels were determined in whole blood using tandem mass spectrometry. Significantly high differences in THCCOOH concentrations were found between the two groups when measured during the screening visit, prior to the smoking session, and throughout the day of the experiment. Receiver operating characteristic (ROC) curves were determined and two threshold criteria were proposed in order to distinguish between these groups: a free THCCOOH concentration below 3 µg/L suggested an occasional consumption (≤ 1 joint/week) while a concentration higher than 40 µg/L corresponded to a heavy use (≥ 10 joints/month). These thresholds were tested and found to be consistent with previously published experimental data. The decision threshold of 40 µg/L could be a cut-off for possible disqualification for driving while under the influence of cannabis. A further medical assessment and follow-up would be necessary for the reissuing of a driving license once abstinence from cannabis has been demonstrated. A THCCOOH level below 3 µg/L would indicate that no medical assessment is required. Copyright © 2013 John Wiley & Sons, Ltd.

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In contrast with mammals and birds, most poikilothermic vertebrates feature structurally undifferentiated sex chromosomes, which may result either from frequent turnovers, or from occasional events of XY recombination. The latter mechanism was recently suggested to be responsible for sex-chromosome homomorphy in European tree frogs (Hyla arborea). However, no single case of male recombination has been identified in large-scale laboratory crosses, and populations from NW Europe consistently display sex-specific allelic frequencies with male-diagnostic alleles, suggesting the absence of recombination in their recent history. To address this apparent paradox, we extended the phylogeographic scope of investigations, by analyzing the sequences of three sex-linked markers throughout the whole species distribution. Refugial populations (southern Balkans and Adriatic coast) show a mix of X and Y alleles in haplotypic networks, and no more within-individual pairwise nucleotide differences in males than in females, testifying to recurrent XY recombination. In contrast, populations of NW Europe, which originated from a recent postglacial expansion, show a clear pattern of XY differentiation; the X and Y gametologs of the sex-linked gene Med15 present different alleles, likely fixed by drift on the front wave of expansions, and kept differentiated since. Our results support the view that sex-chromosome homomorphy in H. arborea is maintained by occasional or historical events of recombination; whether the frequency of these events indeed differs between populations remains to be clarified.

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A cross-over controlled administration study of smoked cannabis was carried out on occasional and heavy smokers. The participants smoked a joint (11 % Δ9-tetrahydrocannabinol (THC)) or a matching placebo on two different occasions. Whole blood (WB) and oral fluid (OF) samples were collected before and up to 3.5 h after smoking the joints. Pharmacokinetic analyses were obtained from these data. Questionnaires assessing the subjective effects were administered to the subjects during each session before and after the smoking time period. THC, 11-hydroxy-THC (11-OH-THC) and 11-nor-9-carboxy-THC (THCCOOH) were analyzed in the blood by gas chromatography or liquid chromatography (LC)-tandem mass spectrometry (MS/MS). The determination of THC, THCCOOH, cannabinol (CBN), and Δ9-tetrahydrocannabinolic acid A (THC-A) was carried out on OF only using LC-MS/MS. In line with the widely accepted assumption that cannabis smoking results in a strong contamination of the oral cavity, we found that THC, and also THC-A, shows a sharp, high concentration peak just after smoking, with a rapid decrease in these levels within 3 h. No obvious differences were found between both groups concerning THC median maximum concentrations measured either in blood or in OF; these levels were equal to 1,338 and 1,041 μg/L in OF and to 82 and 94 μg/L in WB for occasional and heavy smokers, respectively. The initial WB THCCOOH concentration was much higher in regular smokers than in occasional users. Compared with the occasional smokers, the sensation of confusion felt by the regular smokers was much less while the feeling of intoxication remained almost unchanged.

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Introduction: THC-COOH has been proposed as a criterion to help to distinguish between occasional from regular cannabis users. However, to date this indicator has not been adequately assessed under experimental and real-life conditions. Methods: We carried out a controlled administration study of smoked cannabis with a placebo. Twenty-three heavy smokers and 25 occasional smokers, between 18 and 30 years of age, participated in this study [Battistella G et al., PloS one. 2013;8(1):e52545]. We collected data from a second real case study performed with 146 traffic offenders' cases in which the whole blood cannabinoid concentrations and the frequency of cannabis use were known. Cannabinoid levels were determined in whole blood using tandem mass spectrometry methods. Results: Significantly high differences in THC-COOH concentrations were found between the two groups when measured during the screening visit, prior to the smoking session, and throughout the day of the experiment. Receiver operating characteristic (ROC) curves were determined and two threshold criteria were proposed in order to distinguish between these groups: a free THC-COOH concentration below 3 μg/L suggested an occasional consumption (≤ 1 joint/week) while a concentration higher than 40 μg/L corresponded to a heavy use (≥ 10 joints/month). These thresholds were successfully tested with the second real case study. The two thresholds were not challenged by the presence of ethanol (40% of cases) and of other therapeutic and illegal drugs (24%). These thresholds were also found to be consistent with previously published experimental data. Conclusion: We propose the following procedure that can be very useful in the Swiss context but also in other countries with similar traffic policies: If the whole blood THC-COOH concentration is higher than 40 μg/L, traffic offenders must be directed first and foremost toward medical assessment of their fitness to drive. This evaluation is not recommended if the THC-COOH concentration is lower than 3 μg/L. A THC-COOH level between these two thresholds can't be reliably interpreted. In such a case, further medical assessment and follow up of the fitness to drive are also suggested, but with lower priority.

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abstract:occasional Adnominal Idiom Modification - A Cognitive Linguistic Approach From a cognitive-linguistic perspective, this paper explores alternative types of adnoniinal modification in occasional variants of English verbal idioms. Being discussed against data extracted from the British National Corpiis (BNC), the model claims that in idioni-production idiomatic constructions are activated as complex linguistic schemas to code a context-specific target-conceptualisation. Adnominal pre- and postmodifications are one specific form of creative alteration to adapt the idiom for this purpose. Semantically, idiom-interna1 NPextension is not a uniforni process. It is necessary to distinguish two systematic types of adnominal modification: external and internal modification (Ernst 1981). While external NPmodification has adverbial function, ¡.e. it modifies the idiom as a unit, internal modification directly applies to the head-noun and thus depends on the degree of motivation and analysability of a given idiom. Following the cognitive-linguistic framework, these dimensions of idiom-transparency result from the language user's ability to remotivate the bipartite semantic structure by conceptual metaphors and metonymies.

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Research has suggested that exogenous opioid substances can have direct effects on cardiac muscle or influence neurotransmitter release via presynaptic modulation of neuronal inputs to the heart. In the present study, multiple-labelling immunohistochemistry was employed to determine the distribution of endogenous opioid peptides within the guinea-pig heart. Approximately 40% of cardiac ganglion cells contained immunoreactivity for dynorphin A (1-8), dynorphin A (1-17) and dynorphin B whilst 20% displayed leu-enkephalin immunoreactivity. Different populations of opioid-containing ganglion cells were identified according to the co-existence of opioid immunoreactivity with immunoreactivity for somatostatin and neuropeptide Y. Immunoreactivity for prodynorphin-derived peptides was observed in many sympathetic axons in the heart and was also observed, though to a lesser extent, in sensory axons. Leu-enkephalin immunoreactivity was observed in occasional sympathetic and sensory axons. No immunoreactivity was observed for met-enkephalin-arg-gly-leu or for beta-endorphin. These results demonstrate that prodynorphin-derived peptides are present in parasympathetic, sympathetic and sensory nerves within the heart, but suggest that only the prodynorphin gene is expressed in guinea-pig cardiac nerves. This study has shown that endogenous opioid peptides are well placed to regulate cardiac function via both autonomic and sensory pathways.

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The thesis examines the impact of collective war victimization on individuals' readiness to accept or assign collective guilt for past war atrocities. As a complement to previous studies, its aim is to articulate an integrated approach to collective victimization, which distinguishes between individual-, communal-, and societal-level consequences of warfare. Building on a social representation approach, it is guided by the assumption that individuals form beliefs about a conflict through their personal experiences of victimization, communal experiences of warfare that occur in their proximal surrounding, and the mass- mediatised narratives that circulate in a society's public sphere. Four empirical studies test the hypothesis that individuals' beliefs about the conflict depend on the level and type of war experiences to which they have been exposed, that is, on informative and normative micro and macro contexts in which they are embedded. The studies have been conducted in the context of the Yugoslav wars that attended the breakup of Yugoslavia, a series of wars fought between 1991 and 2001 during which numerous war atrocities were perpetrated causing a massive victimisation of population. To examine the content and impact of war experiences at each level of analysis, the empirical studies employed various methodological strategies, from quantitative analyses of a representative public opinion survey, to qualitative analyses of media content and political speeches. Study 1 examines the impact of individual- and communal- level war experiences on individuals' acceptance and assignment of collective guilt. It further examines the impact of the type of communal level victimization: exposure to symmetric (i.e., violence that similarly affects members of different ethnic groups, including adversaries) and asymmetric violence. The main goal of Study 2 is to examine the structural and political circumstances that enhance collective guilt assignment. While the previous studies emphasize the role of past victimisation, Study 2 tests the assumption that the political demobilisation strategy employed by elites facing public discontent in the collective system-threatening circumstances can fuel out-group blame. Studies 3 and 4 have been conducted predominantly in the context of Croatia and examine rhetoric construction of the dominant politicized narrative of war in a public sphere (Study 3) and its maintenance through public delegitimization of alternative (critical) representations (Study 4). Study 4 further examines the likelihood that highly identified group members adhere to publicly delegitimized critical stances on war. - Cette thèse étudie l'impact de la victimisation collective de guerre sur la capacité des individus à accepter ou à attribuer une culpabilité collective liée à des atrocités commises en temps de guerre. En compléments aux recherches existantes, le but de ce travail est de définir une approche intégrative de la victimisation collective, qui distingue les conséquences de la guerre aux niveaux individuel, régional et sociétal. En partant de l'approche des représentations sociales, cette thèse repose sur le postulat que les individus forment des croyances sur un conflit au travers de leurs expériences personnelles de victimisation, de leurs expériences de guerre lorsque celle-ci se déroule près d'eux, ainsi qu'au travers des récits relayés par les mass media. Quatre études testent l'hypothèse que les croyances des individus dépendent des niveaux et des types d'expériences de guerre auxquels ils ont été exposés, c'est-à-dire, des contextes informatifs et normatifs, micro et macro dans lesquels ils sont insérés. Ces études ont été réalisées dans le contexte des guerres qui, entre 1991 et 2001, ont suivi la dissolution de la Yougoslavie et durant lesquelles de nombreuses atrocités de guerre ont été commises, causant une victimisation massive de la population. Afin d'étudier le contenu et l'impact des expériences de guerre sur chaque niveau d'analyse, différentes stratégies méthodologiques ont été utilisées, des analyses quantitatives sur une enquête représentative d'opinion publique aux analyses qualitatives de contenu de médias et de discours politiques. L'étude 1 étudie l'impact des expériences de guerre individuelles et régionales sur l'acceptation et l'attribution de la culpabilité collective par les individus. Elle examine aussi l'impact du type de victimisation régionale : exposition à la violence symétrique (i.e., violence qui touche les membres de différents groupes ethniques, y compris les adversaires) et asymétrique. L'étude 2 se penche sur les circonstances structurelles et politiques qui augmentent l'attribution de culpabilité collective. Alors que les recherches précédentes ont mis l'accent sur le rôle de la victimisation passée, l'étude 2 teste l'hypothèse que la stratégie de démobilisation politique utilisée par les élites pour faire face à l'insatisfaction publique peut encourager l'attribution de la culpabilité à l'exogroupe. Les études 3 et 4 étudient, principalement dans le contexte croate, la construction rhétorique du récit de guerre politisé dominant (étude 3) et son entretien à travers la délégitimation publique des représentations alternatives (critiques] (étude 4). L'étude 4 examine aussi la probabilité qu'ont les membres de groupe fortement identifiés d'adhérer à des points de vue sur la guerre critiques et publiquement délégitimés.