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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The effects of heat strain in psychological performance

O'Connor, Elinor Margaret January 1999 (has links)
The impact of thermal stress on psychological performance has been the subject of considerable research attention. However, the effects of heat on performance are poorly understood. The literature yields inconsistent results, reflecting methodological shortcomings in previous research, particularly with regard to the definition of the independent variable. Investigators have focused on heat stress per se to the neglect of the participants' thermal physiological response. In addition, investigators have typically tested small samples, and have relied on a limited range of performance measures of unknown sensitivity. Few theoretical accounts of performance during thermal stress have been proposed, and these are poorly elaborated. The principal aim of this research programme was to elucidate the effects of heat on psychological performance. Emphasis was placed on defining the independent variable in terms of physiological strain. Performance was measured using a comprehensive range of sensitive tasks. In the first and second experiments, an innovative water immersion technique was used to control thermal strain precisely. The principal effect of heat strain observed in these experiments was an increase in the speed of performance, without variation in accuracy. This effect was attributed to an increase in nerve conduction velocity associated with raised body temperature. The duration of immersion in the second experiment was fifty percent longer than that in the first, but little variation in performance with the duration of heat strain was evident. In light of the limited external validity of the immersion experiments, subsequent investigation focused on the effects of more realistic sources of thermal strain. A survey of military personnel indicated that occupational exposure to thermal stress is perceived to impair some cognitive and psychomotor functions. The final experiment measured performance during prolonged exposure to heat stress in a climatic chamber. The results indicate that the performance changes observed in the immersion experiments generalize to conditions involving exposure to more realistic sources of heat strain
2

EXAMINATION OF ELECTRONIC CIGARETTE USER PUFF TOPOGRAPHY: THE EFFECT OF A MOUTHPIECE-BASED TOPOGRAPHY MEASUREMENT DEVICE ON PLASMA NICOTINE AND SUBJECTIVE EFFECTS

Spindle, Tory 01 January 2015 (has links)
Electronic cigarettes (ECIGs) operate by heating a nicotine-containing solution resulting in an inhalable aerosol. Nicotine delivery may be affected by users’ puffing behavior (puff topography), and little is known about the puff topography of ECIG users. The purpose of this study was to examine the extent to which a mouthpiece-based topography measurement device influences the acute effects associated with ECIG use. Twenty-nine experienced ECIG users completed two sessions differing only by the presence of a mouthpiece-based topography recording device. In both sessions, participants completed one 10 puff, 30 sec inter-puff interval (IPI) ECIG-use bout and another 90 minute ad libitum bout. Acute ECIG effects (plasma nicotine concentration, heart rate [HR], and subjective effects) were largely unaffected by the presence of the topography recording device. Evaluating ECIG puff topography through clinical laboratory methodology is necessary to understand the effects of these products (including toxicant exposure) and to inform their regulation.
3

Effects of Repeated Cue Exposure on Cannabis Craving

Fogel, Jessica S 01 January 2015 (has links)
Craving is a key element of the cannabis withdrawal syndrome that has been associated with continued use and relapse. Although cue-induced cannabis craving has been established in single laboratory sessions, procedures to sustain craving over multiple sessions are needed. The purpose of the present study was to determine if cue-induced craving responses could be elicited in the same subjects across multiple sessions. It was hypothesized that exposure to cannabis cues would produce more robust craving responses than exposure to neutral cues and that elicited craving responses will be sustained across multiple cue exposures. Five experimental cue exposure sessions (1 neutral and 4 cannabis) were conducted. Craving was assessed with the Marijuana Craving Questionnaire (MCQ) Short Form, Visual Analog Scale (VAS), Subject-Rated Physiological Questionnaire, blood pressure, and heart rate. Results revealed significant effects of initial cannabis cue exposure on VAS craving responses and Subject-Rated Physiological measures relative to the neutral cue exposure condition. No significant differences were found on MCQ composite scores or physiological measures. Craving responses following initial cannabis cue exposure were not maintained across sessions. There is a need for a better understanding of the factors that contribute to continued drug use despite quit attempts.
4

Are Subjective Effects More Extreme with Higher-Potency Cannabis? A Within-Person Comparison of the Subjective Effects of Marijuana and Butane Hash Oil.

January 2019 (has links)
abstract: Background: Hash oil, a cannabis preparation that contains ultra-high concentrations of tetrahydrocannabinol (THC), is quickly gaining popularity in the United States. Some evidence suggests that hash oil might produce greater intoxication and more severe negative effects than marijuana. This study examined whether the subjective effects of hash oil are more extreme than the subjective effects of marijuana and whether frequency of hash oil use is associated with the subjective effects of marijuana and hash oil. Method: Past-year cannabis users (n = 1,268) were recruited online to complete a questionnaire about the subjective effects of cannabis. Participants who reported past-year use of both hash oil and marijuana (n = 574) rated subjective effects of each type of cannabis in the following positive and negative domains: positive affect, cognitive enhancement, negative affect, cognitive impairment, physiological effects, reduced consciousness, and psychotic-like experiences. Results: Results of within-person comparisons showed that hash oil was rated as producing lesser positive effects (Hash oil: M = 4.53, Marijuana: M = 5.55, t = 14.67, p < .001) than marijuana. Negative effects of hash oil were minimal for the full sample (n = 574) and for both frequent and infrequent hash oil users. In general, the frequency of hash oil use was not associated with the subjective effects of marijuana but more frequent hash oil use was associated with rating hash oil as producing greater positive effects ( = 0.28, t = 6.86, p < .001) and lesser negative effects ( = -0.16, t = -3.83, p < .001). Findings were unchanged after controlling for sex, medical cannabis use, and frequency of marijuana use. Conclusions: Hash oil produced lesser positive effects than marijuana. Negative effects of hash oil were minimal, suggesting that extreme negative effects may be unlikely for experienced cannabis users. / Dissertation/Thesis / Masters Thesis Psychology 2019
5

Reinforcing Effects of D-Amphetamine: Influence of Novel Ratios on a Progressive-Ratio Schedule

Sevak, Rajkumar J., Stoops, William W., Glaser, Paul E. A., Hays, Lon R., Rush, Craig R. 01 December 2010 (has links)
Progressive-ratio schedules are useful for studying the reinforcing effects of drugs. Earlier human laboratory studies showed that d-amphetamine significantly increased break points relative to placebo. However, the magnitude of the increase was modest, which may be attributable to rather high levels of placebo responding. We used novel response requirements in a modified progressive-ratio procedure and hypothesized that the altered range of response requirements would decrease responding for placebo and increase responding for d-amphetamine. Eight participants completed the study. The participants first sampled oral doses of d-amphetamine (0, 8, 16, and 24mg). In subsequent sessions, the participants were offered the opportunity to work for the sampled dose on a modified progressive-ratio procedure with response requirements ranging from 400 to 1800 mouse clicks. A battery of participant-rated drug-effect questionnaires, a performance measure, and cardiovascular measures were included to more fully characterize the effects of d-amphetamine. Placebo maintained low levels of responding. The intermediate dose of d-amphetamine increased responding significantly above placebo levels. d-Amphetamine produced prototypical subject-rated effects that were an orderly function of dose. These data suggest that the modified response requirements resulted in lower levels of placebo taking and a larger separation between the number of placebo and d-amphetamine capsules earned. Behavioural Pharmacology.
6

Abrangência da coisa julgada e ações coletivas (lato sensu) efeito erga omnes e (in)constitucionalidade legal

Alves, Maíra Feltrin 18 October 2012 (has links)
Made available in DSpace on 2016-04-26T20:21:16Z (GMT). No. of bitstreams: 1 Maira Feltrin Alves.pdf: 8584122 bytes, checksum: 2ddba294640f1d620f960ca028daaaff (MD5) Previous issue date: 2012-10-18 / This paper discusses the normative propositions about the res judicata broadly in collective action and, given the dynamics and scope of this kind of action, that legal institution should operate. To be considered both the legal and the guiding principles of constitutional and collective process leading to interpretation from constitucion as to who can give the best possible outcome observing the systematic legal and essence of collective action lato sensu. The big question that arises is whether or not there would be a limitation of the subjective effects of res judicata in view of the existence of express statutory rule for both. The issue raises a lot of discussion and must be faced with assertiveness that fits the legal system itself. We tried the method to present deductive logical conclusion indicates that the unconstitutionality of any limitation on the effectiveness of geographically broad and unrestricted res judicata in the collective process / O presente trabalho pretende demonstrar as proposições normativas sobre a coisa julgada na ação coletiva lato sensu e, diante da dinâmica e escopo desse tipo de ação, o referido instituto jurídico deve operar. Para tanto são consideradas as disposições legais e os princípios norteadores constitucionais e do processo coletivo, conduzindo a uma interpretação conforme para que se possa dar o resultado mais adequado possível observando-se a sistemática do ordenamento jurídico e a essência da ação coletiva lato sensu. A grande questão que se apresenta é se haveria ou não a limitação dos efeitos subjetivos da coisa julgada, tendo em vista a existência de regra legal expressa para tanto. O tema suscita bastante discussão e precisa ser enfrentado com assertividade para que o sistema jurídico se adéqüe em si mesmo. Buscou-se o método lógico dedutivo para apresentar a conclusão que indica à inconstitucionalidade de qualquer limitação à eficácia ampla e irrestrita territorialmente da coisa julgada no processo coletivo

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