Tesi sul tema "Methodological issues"

Retrospective pretests provide a potentially useful elaboration on research methodology if they can be shown to be dependable under specific sets of conditions. Previous studies have examined response-shift bias and response-style effects, but less attention has been given to memory distortion associated with the retrospective recall of diverse types of variables. Identifying psychometric characteristics of these measures may help to clarify the picture emerging from retrospective accounts. The present study applied a methodology developed to measure the systematic error (i.e., memory distortion) that may be associated with variables involving a range of recall tasks. The study examined which types of variables account for the least measurement error in retrospective pretests administered at three time points. The types of variables examined in this study include students' self-ratings of academic abilities, self-reported attitudes and opinions about college, mood states, and perceptions of general health. The results of this study indicate that there was no main effect of time on any of the pairs of difference scores, and a moderate level of memory distortion was detected in the three variable types examined. The methodology applied provides an effective approach to understanding the effect of memory distortion on retrospective pretest variables. The author recommends that future applications of this methodology be applied to heterogeneous populations, investigate a range of complex variables, and include an examination of individual subject differences.

Cette thèse explore différents problèmes méthodologiques associés à l'évaluation non-marchande. Dans la première partie, je m'intéresse à certaines difficultés posées par l'élicitation des préférences. En particulier, j'analyse les performances d'un nouveau format d'élicitation pour réduire le biais d'ancrage des consentements à payer (Chapitre 1). J'étudie aussi l'effet de la confiance dans les institutions sur les comportements de protestation dans les questionnaires d'évaluation (Chapitre 2). La seconde partie de la thèse est dédiée à l'analyse statistique des consentements à payer. Je compare les modèles de régressions quantiles avec les modèles standards pour mesurer leur capacité à prendre en compte des caractéristiques récurrentes des données de consentement à payer (Chapitre 3). Je propose aussi un test pour un nouveau type de biais de publication (Chapitre 4). Dans la dernière partie, je m'intéresse aux problèmes d'équité liés à l'agrégation des consentements à payer pour mesurer les bénéfices d'un projet, et le rôle joué par les besoins de subsistance (Chapitre 5)
In this thesis I explore different methodological issues arising in non-market valuation. In the first part of the thesis, I try to provide solutions to some problems of preference elicitation. In particular, I analyze the performance of a new elicitation format to reduce anchoring bias in multiple willingness to pay (WTP) elicitation (Chapter 1) and I propose a new strategy to identify the effect of trust in institution on protesting behaviors (Chapter 2). The second part of the thesis is devoted to the statistical analysis of WTP. I compare quantile regression models with standard models to assess their respective ability to account for recurrent issues in WTP data (Chapter 3), I also propose a test for a new type of publication bias (Chapter 4). In the last part of the thesis, I investigate the equity issues in WTP aggregation as a measure of benefits, and the role of subsistence needs (Chapter 5)

Fahrerablenkung ist ein Begriff, der in den vergangen Jahren verstärkt in das Blickfeld der Öffentlichkeit geraten ist. Dies ist im Wesentlichen zurückzuführen auf die deutlich steigende Verbreitung und Nutzung von Fahrerinformationssystemen. Gleichzeitig führt die steigende Automatisierung im Fahrzeug dazu, dass dem Fahrer in seiner subjektiven Wahrnehmung mehr Ressourcen zur Verfügung stehen, um sich anderen Aktivitäten wie etwa Essen, Rauchen oder Telefonieren zuzuwenden. Die steigende Aktualität dieser Problematik wirft viele Fragen auf. Wie häufig tritt Fahrerablenkung auf? Welche Konsequenzen hat sie? Welche kognitiven Prozesse zeichnen für diese Konsequenzen verantwortlich? Und wie kann man Fahrerablenkung messen? Die vorliegende Dissertation besteht aus drei empirischen Beiträgen, sowie einer kurzen Einführung, die die grundlegenden Fragen und Befunde zum Thema Fahrerablenkung betrachtet. Das Augenmerk des ersten Beitrags liegt auf der Überprüfung theoretischer Annahmen zur Fahrerablenkung. Eine Vielzahl von Untersuchungen zeigt, dass sich kognitiv beanspruchende Zweitaufgaben negativ auf die Fahrleistung auswirken. Im vorliegenden Beitrag wird davon ausgegangen, dass dieser Effekt eine Folge von Interferenzen zwischen den Funktionen des Arbeitsgedächtnisses, die dazu dienen das Situationsmodell der Verkehrssituation aktuell zu halten, und den bearbeiteten Zweitaufgaben ist. Im Rahmen einer Simulatorstudie wurde diese Annahme überprüft. Es zeigte sich, dass die Probanden, die eine Zweitaufgabe ausführten, die speziell die Integration von neuen Informationen in das bestehende Situationsmodell behindern sollte, später auf antizipierbare kritische Ereignisse reagierten als Vergleichsgruppen. Im Gegensatz dazu ergaben sich für unvorhersehbare Ereignisse keine Unterschiede. Diese Ergebnisse weisen darauf hin, dass die negativen Effekte kognitiver Belastung tatsächlich auf Interferenzen mit spezifischen Arbeitsgedächtnisprozessen zurückzuführen sind. Die beiden weiteren Beiträge befassen sich mit messmethodischen Fragen in Bezug auf Fahrerablenkung. In Beitrag zwei wird die Lane Change Task (LCT) thematisiert, eine Labormethode zur Erfassung von Ablenkung. Aufgabe der Probanden ist die Steuerung eines virtuellen Fahrzeuges mittels Lenkrad, und dabei konkret die Ausführung von Spurwechseln, bei gleichzeitiger Bearbeitung von Zweitaufgaben. Trotz eines standardisierten Versuchsaufbaus sind allerdings starke Messvarianzen zwischen verschiedenen Testreihen zu beobachten. Der Übungsgrad der Versuchsteilnehmer wurde dabei als eine mögliche Ursache identifiziert. In zwei Experimenten wurde dieser Vermutungnachgegangen. Probanden bearbeiteten parallel zur LCT Zweitaufgaben verschiedener Schwierigkeitsstufen, nachdem sie zuvor trainiert wurden. Es konnte gezeigt werden, dass der Grad der Übung tatsächlich einen Einfluss auf die Spurwechselperformanz hat, und dass dieser Einfluss auch Monate später noch zu finden ist. Es ist jedoch zweifelhaft, dass dieser Effekt allein ursächlich für die zu beobachtenden Messvarianzen ist. Im dritten Beitrag wird die Critical Tracking Task (CTT) betrachtet, ein Verfahren, das im Kontext Fahrerablenkung bisher kaum Beachtung fand. Die CTT ist eine einfache Trackingaufgabe, welche vom Nutzer die Stabilisierung eines dynamischen, instabilen Elementes auf einem Bildschirm fordert. Die zur Bearbeitung der Aufgabe auszuführenden Tätigkeiten der kontinuierlichen visuellen Überwachung und manuellen Kontrolle sind grundsätzlich vergleichbar mit basalen Anforderungen der Fahraufgabe. Ziel war es, das Potenzial der CTT als Messverfahren von Fahrerablenkung durch Fahrerinformationssysteme zu überprüfen. Die Ergebnisse der vier durchgeführten Experimente, in denen sowohl künstliche als auch reale Aufgaben und Systeme bearbeitet und bedient wurden, legen den Schluss nahe, dass die CTT in der Tat in der Lage ist, das Ausmaß von Ablenkung ausgelöst durch Fahrerinformationssysteme zu quantifizieren.

Aim: To examine the multi-faceted menorrhagia complaint in terms of: subjective account of menstrual periods and symptoms, psychosocial measures, socio-demographic factors, and objective measurement of the menstrual loss. Study population: All women aged 25 to 49 years newly referred for menstrual problems to collaborating consultants at gynaecology clinics at Edinburgh and Glasgow Royal Infirmaries, and Glasgow Western Infirmary. Problems eligible for inclusion in the survey were excessive periods, period paid, premenstrual changes, ‘period problems’ (non-specific) and irregular periods. Only those with putatively heavy periods (referral for that reason, or subjective judgement) were invited to have their blood loss measured. Methods: Survey data were collected using the brief Clinic Questionnaire (ascertaining minimal essential data from as many as possible of the eligible clinic population); a more detailed Menstrual Evaluation Questionnaire; and the Menstrual Background Questionnaire (addressing contraceptive and obstetric history, and general health). The SF-36 quality-of-life questionnaire was also used. A Menstrual Chart was developed for the menstrual collection, and both total menstrual fluid loss and blood loss volume were measured. Results: The 952 women recruited were representative, in terms of age, socio-economic status and referral condition, of all 1506 eligible referrals. The 226 who had their menstrual loss measured were socio-demographically representative of all 865 women eligible for this stage. Case notes were found and reviewed for 665 (89%) of the 748 recruited early enough to be followed-up. The study sample is described in terms of socio-demographic factors, referral reasons, subjective report of periods, quality-of-life, well-being and clinic outcome, and for the relevant subset, menstrual loss volumes. Prior hypotheses with regard to associations between these factors are evaluated and reported. Methodological issues in menorrhagia assessment and measurement are considered. Conclusions: The current focus on volume of blood loss in menorrhagia complaint is unhelpful, since it ignores the associated symptoms and social disability that play a key role in leading a woman to seek help for her periods. The 80 ML criterion is of dubious clinical utility as it is neither sensitive nor specific for adverse impact of periods, compromised iron status, or pathology.

The overall aim of this thesis was to investigate psychosocial consequences of cancer during adolescence, using a longitudinal approach. An additional aim was to investigate if mode of administration has an influence on adolescents’ and young adults’ self-reported psychosocial function. In Study I participants, aged 13-23 years, were randomised according to two modes of administration, telephone interview and postal questionnaire, and asked to complete the Hospital Anxiety and Depression Scale (HADS) and Short Form 36 (SF-36). The telephone mode resulted in a higher response rate, better self-rated psychosocial function (except for the youngest age group), overall lower Cronbach’s alpha values, and a larger percentage of ceiling effects compared to the postal mode. A higher proportion of males than females chose not to participate in the postal mode. In Study II and III adolescents diagnosed with cancer completed the HADS and two sub-scales from the SF-36 (Mental Health and Vitality) 4-8 weeks, 6, 12, and 18 months after diagnosis. In Study II adolescents with cancer were compared to a reference group from the general population. Shortly after diagnosis the cancer group rated their psychosocial function as worse compared to the reference group. However, the differences gradually disappeared over time and were then reversed, resulting in the cancer group reporting better vitality and lower levels of anxiety and depression than the reference group eighteen months after diagnosis. In Study III five distinct psychosocial states were identified, characterised by: psychosocial dysfunction (state A), poor psychosocial function (state B), incomplete psychosocial function (state C), good psychosocial function (state D), and excellent psychosocial function (state E). Shortly after diagnosis more adolescents than expected by chance were found in states A and C and fewer were found in states D and E. Eighteen months after diagnosis a different pattern emerged, where more adolescents than expected were found in state E and fewer than expected in state C. In Study IV adolescents, two years after diagnosis, reported problems with physical impairment, intrusive thoughts, feelings of alienation, and problems catching up with school. However, a majority of the participants also reported positive consequences with regard to the cancer disease: a more positive view of life, good self-esteem, knowledge and experience with regard to disease and hospital care, good relations, broader perspectives, and material gains. Study V, a review of the literature, indicates that survivors of childhood/adolescent cancer do not differ from comparison groups with regard to relations to others and relation to self. However, some findings highlight that friendship and marital status are areas of concern, and parenthood and sexuality are areas of potential concern. In conclusion, mode of administration influences adolescents’ and young adults’ self-reported psychosocial function and is related to age. Psychosocial function increases with time from diagnosis for most adolescents diagnosed with cancer. However, some individuals remain in poor psychosocial states during the first eighteen months after diagnosis. Increased efforts should be taken to identify these individuals.

The POINT-AGAPE collaboration, an international project looking for gravitational microlensing towards the Andromeda galaxy, uses the 'superpixel' technique to detect MAssive Compact Halo Objects (MACHOs). The 3-year survey has discovered about a dozen microlensing candidates. Part I of the thesis describes the project's background. Dark matter is discussed (cliapter 1). Microlensing is explained, emphasising the POINT-AGAPE work, and the superpixel technique is introduced (chapter 2). CCD technology and the Isaac Newton Telescope are discussed (chapter 3). In Part II the three recent POINT-AGAPE pipelines and their results are detailed, including the work at Queen Mary. The elimination of Mira variables is discussed, these masquerade as microlensing events (chapters 4 - 6). In addition we estimate the efficiency of detecting microlensing events (chapter 7). Part III describes various methodological issues associated with thesuperpixel technique, which uses a program called SExtractor to detect lightcurves with a bump. However, this generates fake lightcurves associated with CCD defects, bad pixels and resolved stars. Likelihood maps are investigated (chapter 8). The bad pixels and resolved stars were masked, but no mask is perfect and it is important to understand the degree of incompleteness. CCD defects are studied, their causes and effects are analysed; as are bright variable objects (chapter 9). In particular, a new method is described, involving close pairs of variables, which can be used in analysing the defects (chapter 10). Tight groups of variables are studied and bad columns analysed (chapter 11). Telescope pointing is investigated, relating offsets with defects and analysing anomalies in the bad columns. Field close pairs are discussed; once defective pairs are accounted for, what remains are genuine close pairs (chapter 12). Part IV discusses a search made for Cepheids (chapter 13) and summarises a coauthored paper on Nova discoveries in M31 (chapter 14). This is followed with appendicies with some more technical details. collaboration, an international project looking for gravitational microlensing towards the Andromeda galaxy, uses the 'superpixel' technique to detect MAssive Compact Halo Objects (MACHOs). The 3-year survey has discovered about a dozen microlensing candidates.

Multidimensional deprivation and persistent poverty are important research areas within the poverty measurement literature. Still, both encompass measurement issues for which methodological solutions are yet to be analysed. The thesis that I present here analyses three specific measurement issues, identified as relevant within these research areas, and proposes methodological approaches to tackle each of them. First, it evaluates the effect of different demographic population structures on societal multidimensional deprivation incidence comparisons. The results of this evaluation demonstrate that societal multidimensional comparisons reflect not only differences in relative deprivation but also differences in the demographic composition of the societies to be compared. These differences in the demographic structure of the population, thus, confound societal multidimensional deprivation comparisons. To tackle this comparability problem, the application of direct and indirect standardisation methods is proposed and analysed in this context. Second, it studies the effect of differences in need, exhibited across individuals from different demographic population subgroups or households of different sizes and compositions, on multidimensional deprivation incidence profiles. To address differences in needs and enhance individual or household comparability, I propose a family of multidimensional deprivation indices that describes how much deprivation two demographically heterogeneous units with different needs must exhibit to be catalogued as equivalently deprived. The obtained empirical results demonstrate that neglecting differences in needs yields biased multidimensional deprivation incidence profiles. The results also shed light on the ability of my proposed family of measures to capture these differences in need effectively. Third, this thesis analyses the reliability of persistent poverty measures in the presence of survey non-response. The obtained empirical results indicate that persistent poverty measures based on balanced panel estimates that do not account for the relationship between survey non-response and the socioeconomic status of the household provide a significantly biased picture of the intertemporal phenomenon. The methodologies that I present in this thesis are meant foremost to be easy to implement and understand by policymakers. As such, they are proposed as methodological tools to improve the measurement and analysis of poverty in the policy context.

This thesis explored a number of methodological issues present in motor cognition research using transcranial magnetic stimulation (TMS). The facilitatory effect of the corticospinal pathway during observation of simple hand actions was also investigated. TMS was applied to the motor cortex during action observation and the resulting MEP peak-to-peak amplitudes were analysed. A series of four studies were conducted to test whether a motor facilitation effect specific to the muscles involved in the observed actions were obtained, while simultaneously investigating five prominent methodological concerns in TMS research. In Study 1 the issue of choosing the optimal control condition was investigated. The MEP facilitation obtained during action observation (ball pinch) was compared to two commonly used control conditions (fixation cross and static image). Consistent with published literature, the action condition resulted in larger MEP amplitudes than the controls. There was no statistical difference in MEP amplitude between the two resting conditions. It was argued, however, that the static image allows for more accurate comparison with the action condition by providing meaningful visual cues without the associated action. In Study 2, the effect of short-term physical execution on the relationship between observed actions and neural activity was explored. The motor facilitation effect was present during action observation. This was not enhanced following execution of the observed action which is in contrast with the literature that shows the observation-execution matching system tuned to familiarity with an action. In TMS studies, different stimulation timings are included in order to reduce anticipatory effects of the TMS pulse. While the different timings are usually analysed together, in Studies 1 and 2, the two stimulation timings were analysed separately. As a consequence, a motor facilitation effect was only evident for the earlier stimulation timing of 6250ms in Study 1. When participants executed the action prior to observing it in Study 2, there was no effect of stimulation timing, leading to speculation that the prior execution may have had some effect on the attentional demands during the subsequent observation. Studies 3 and 4 explored two general methods concerns regarding the motor hotspot and stimulation intensity. In Study 3, the muscle- vi specificity notion was explored via observation of index finger and little finger movements versus observation of a static hand, with the corresponding muscles tested at their individual hotspots. This was a novel approach as one hotspot is typically used for all muscles under investigation. The choice of motor hotspot, however, did not significantly affect the muscle-specific findings, providing further support for the muscle-specific motor facilitation findings reported in the literature. Finally, Study 4 investigated the concept of stimulation intensity. TMS action observation studies differ in the stimulation intensities used, typically ranging from 110% to 130% of resting motor threshold. Since the motor response obtained through TMS may be affected depending on the stimulation intensity used, two stimulation intensities were employed (high vs. low) during observation of finger movements. A motor facilitation effect was reported in the low intensity stimulation, which was expected given that near threshold intensities are more representative of the ongoing level of cortical excitability. No motor facilitation effect was shown in the high intensity stimulation, possibly due to the nature of high stimulation intensities on the corticospinal pathway, or simply because the low intensity stimulations were always delivered before the high intensity stimulations. In light of the stimulation timing findings of Study 1, this may have resulted in participants getting distracted or fatigued, focussing their attention elsewhere (and therefore lowering MEP amplitudes) during the latter high stimulations. From the results presented in these studies, it is clear that there is a muscle specific motor facilitation during action observation and its characteristics are influenced by many procedural, technical and cognitive and attentional factors. This thesis provides a much needed critical analysis into the methods and methodologies commonly adopted in this area of research. It is essential to continue to explore the methods employed in TMS motor cognition studies, making them accepted universally and scientifically rigorous.

This thesis is concerned with current debates as to the value of patient satisfaction research. The thesis reports two surveys by means of which the scope of patient satisfaction research is considered. Conceptual and methodological problems in this field of research and alternative theories of the social process whereby patients evaluate health care are reviewed. The two surveys are presented in terms of an introduction to the particular field of medicine involved, the methods of enquiry used, survey responses and discussion of results. The first survey is of patients attending outpatient neurological clinics presenting with headache. This study was conducted with intensive interviews, one before the neurological consultation and a second at home, one month later. The problems of making sense of patients' accounts in terms of 'expectations' and 'satisfaction' are outlined. Instead different perceptions of the value of clinic visits are related to four different concerns felt by patients in relation to their headaches, concerns for reassurance, explanation, prevention and symptomatic treatment. The second survey is of patient satisfaction with outpatient care in a department of genito-urinary medicine. This survey was conducted with two questionnaires: one completed whilst patients waited in the clinic for theirconsultation, and a second which was mailed to patients one month later. Survey results are used to examine an interactionist model of patient satisfaction developed by Ben Sira. The data is examined by various methods to suggest limitations of and modifications to the original model. Finally the thesis assesses the contribution of the two surveys to an understanding of how patients evaluate medical care. Alternative models of patient satisfaction are reexamined. It is argued that some perspectives have too restricted a view of patients' abilities. The implications of the two surveys are reviewed in terms of the different interests researchers may have in surveying patients' views.

New ideas and methodologies need to be developed to advance our knowledge in the understanding of moral development. The intertwined nature of human activities, communication processes, and the numerous aspects of morality pose a challenge to researchers to construct a methodology that takes into account cognition, affect, sociocultural processes and characteristics, as well as the active role of individuals in their own development. In this paper we aim at suggesting fresh theoretical ideas and a micro genetic methodology to study moral development, particularly within educational contexts.
Se parte de la importancia del desarrollo de nueva ideas y metodologías que posibiliten elavance en la interpretación científica del desarrollo moral. La relación entre la ctividad humana, los procesos de comunicación y las cuestiones de moralidad, colocan a los investigadores frente al desafío de desarrollar un abordaje metodológico del desarrollo moral a partir de un enfoque que considere los aspectos cognitivos, afectivos y socioculturales, así como el papel activo de la persona en su proceso de desarrollo. A partir de esas ideas, nuestro objetivo es proponer el análisis microgenético para el estudio del desarrollo moral, tanto desde el punto de vista teórico como metodológico, en el contexto educacional.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
A partir do crescente interesse no estudo da fase pré-clínica das demências possibilitando a identificação clínica precoce do processo de adoecimento, o estudo mais aprofundado do Comprometimento Cognitivo Leve (CCL) torna-se de grande importância. Ele corresponde a uma provável transição para demência e seu diagnóstico pode promover intervenção precoce tanto medicamentosa quanto comportamental. A presente dissertação tem como objetivo investigar as principais questões metodológicas associadas ao uso das medidas neuropsicológicas para definir critérios diagnósticos de CCL, comparando instrumentos cognitivos (Bateria Breve de Rastreio Cognitivo e Escala Mattis de Avaliação de Demência) em uma amostra de idosos assistidos em um ambulatório de geriatria de hospital público do Rio de Janeiro.
The growing interest of preclinical phase of dementia study allow early clinical identification of the disease process, the depth study of Mild Cognitive Impairment (MCI) becomes of great importance. It corresponds to a likely transition to dementia and its diagnosis can promote early both drug and behavior intervention. The present dissertation aims to investigate the main methodological issues associated with the use of neuropsychological measures to establish diagnostics criteria for MCI comparing cognitive instruments (Brief Cognitive Screening Battery and Mattis Dementia Rating Scale) in an elderly sample assisted in a geriatric outpatient clinic of a public hospital in Rio de Janeiro.

The accurate determination of malingering relies on the use of validated and clinically relevant assessment measures. Simulation design is the most often-used research design to accomplish this. However, its external validity is sometimes questioned. The goal of the thesis was to systematically evaluate these major elements: situation, incentives, and coaching. The situation in simulation studies can vary from relevant (academic failure in a college population) to irrelevant (capital murder) for the samples being studied. Incentives refer to the external motivation given to improve simulators' performance and can be positive (extra credit and monetary reward) or negative (extra time and effort). Finally, coaching refers to whether the participant receives any information on detection strategies that are designed to identify feigners. Using a large undergraduate sample in a factorial design, results indicate that a scenario familiar to the participants generally improved the believability of their responses. Coaching also improved the ability to feign convincingly, while incentive type was not associated with any change in scores. The implications of these findings for future research designs and the connection to practice are discussed.

Increasing use of cannabis for therapeutic purposes raises safety concerns; however, epidemiological studies have not been conducted to specifically evaluate the safety of herbal cannabis used for medical purposes. Available safety information comes primarily from either observational studies that focus on recreational use or from randomized controlled trials (RCTs) that emphasize efficacy as the primary study objective.
This thesis seeks to improve our understanding of the safety of medical cannabis use. Existing safety information was first assessed in a meta-analysis of all cannabinoid RCTs and a separate systematic review of recreational cannabis. Following this, a prospective cohort study [Cannabis for the Management of Pain, Assessment of Safety Study (COMPASS)] was then conducted. A total of 215 subjects (chronic pain patients who used cannabis provided by Health Canada in the study) and 216 controls (who did not use cannabis) were recruited from across Canada. Adverse events were collected over a one-year period to assess the safety of herbal cannabis for the treatment of chronic pain. In considering the most efficient strategy to control for potential confounders in the development of COMPASS, the statistical efficiency of matching and a multiple model with an adjustment for confounders were compared in a separate project.
This thesis improves our knowledge about adverse events associated with medical cannabis (pharmaceutical cannabinoid products and herbal cannabis), and contributes to the discussion concerning its therapeutic uses from a safety point of view. The consistency of results from our meta-analysis and the COMPASS study allows us to more firmly conclude that medical cannabis was associated with an increased risk of non-serious adverse events (AEs), in particular in relation to the nervous system and psychiatric disorders, compared to controls. However, the evidence regarding the presence or absence of a potential risk of serious adverse events, among patients on cannabis compared with controls, is inconclusive because the study lacks power.
In conclusion, the results suggest the adverse effects of medical cannabis among experienced users are modest. Further studies with systematic long-term follow-up are required to characterize safety issues among new cannabis users and the risk of serious adverse events.
L'utilisation accrue du cannabis pour des besoins thérapeutiques soulève des questions sur son innocuité; et pourtant, aucune étude épidémiologique n'a été conduite pour évaluer cette innocuité. L'information disponible vient essentiellement, d'études observationnelles d'utilisation du cannabis dans le cadre d'un usage récréatif, ou d'essais cliniques randomisés qui ont comme principal objectif l'évaluation de l'efficacité d'un produit.
Cette thèse cherche à améliorer notre connaissance sur l'innocuité du cannabis pour usage médical. L'information disponible a été initialement utilisée dans le cadre d'une méta-analyse des essais cliniques randomisés sur les cannabinoïdes et ensuite dans le cadre d'une revue systématique des études observationnelles sur l'utilisation du cannabis dans le cadre d'un usage récréatif. Par la suite, une étude de cohorte prospective [Cannabis for the Management of Pain, Assessment of Safety Study (COMPASS)] a été menée. Dans le cadre de cette étude, un total de 215 sujets (des patients ayant une douleur chronique et qui ont utilisé le cannabis fourni dans le cadre du programme de Santé Canada) ainsi que 216 contrôles (des gens avec douleur chrnonique qui n'ont pas utilisé de cannabis) ont été recrutés à travers tout le Canada. Les effets indésirables ont été collectés sur une période d'une année pour évaluer l'innocuité du cannabis. En cherchant la meilleure stratégie pour contrôler les facteurs confondants, dans le cadre de l'étude COMPASS, l'efficience statistique de l'appariement (matching) et du modèle multiple (multiple model) avec ajustement pour les facteurs confondants a été examinée dans un projet séparé. fr
Cette thèse améliore nos connaissances concernant les effets indésirables associés à l'utilisation du cannabis à des fins médicales (cannabinoïdes pharmaceutiques et les feuilles de cannabis), et contribue à la discussion concernant l'usage thérapeutique du cannabis d'un point de vue de son innocuité. La concordance des résultats de notre méta-analyse et de ceux de l'étude COMPASS nous permet de conclure, en comparaison avec le groupe contrôle, l'utilisation du cannabis pour des besoins thérapeutiques est associée à un risque accrue d'effets indésirables moins sévères, en particulier ceux relatifs au système nerveux et aux désordres psychiatriques. Cependant, comparativement au groupe de contrôle, les résultats relatifs au risque potentiel d'effets indésirables sérieux chez les patients exposés au cannabis sont non concluants. fr
En conclusion, les résultats de notre étude suggèrent que les effets indésirables sont minimes parmi les utilisateurs de longue durée du cannabis. D'autres études ayant une période de suivi plus longue sont nécessaires pour déterminer l'innocuité du cannabis parmi les nouveaux utilisateurs et le risque d'effets indésirables graves. fr

Decision-analytic models are increasingly used to inform health policy decisions on adoption and specification of large-scale screening programmes, and to establish the rationale for further scientific inquiries into the effectiveness and cost-effectiveness of alternative screening strategies. While recent years have witnessed considerable methodological advancement in analytical techniques for handling uncertainty in decision-analytic models, the measurement and valuation of health benefits in terms of quality-adjusted life years (QALYs) remains an area of contention, particularly in specific populations such as children. This thesis aims to advance both areas in the context of modelled evaluations of newborn screening programmes.

A presente dissertação tem por objetivo discutir diferentes aspectos de um método de modelagem econômica conhecido por Modelos Stock-Flow Consistent (SFC). Essa classe de modelos tem como principais características a presença de matrizes que representam os balanços patrimoniais dos setores modelados, bem como os fluxos de transações e de fundos financeiros. A primeira etapa do trabalho consiste em analisar as origens dos modelos SFC, apresentando os trabalhos que precederam as primeiras formulações. Em seguida, é feito um survey completo da literatura SFC corrente. Essas duas etapas são realizadas através de uma revisão bibliográfica de artigos, working papers, teses e dissertações. A terceira etapa do trabalho consiste em discutir aspectos metodológicos da modelagem SFC, em especial a modelagem de equações comportamentais de expectativas. Por fim, um modelo SFC é elaborado com o objetivo de analisar o comportamento de uma economia sob quatro regimes fiscais diferentes: (i) balanço equilibrado; (ii) meta de gastos do governo como proporção do PIB; (iii) meta de déficit do governo como proporção do PIB; (iv) meta de dívida pública como proporção do PIB. O comportamento em estado estacionário desses regimes é analisado, bem como sua resiliência a choques. Entre as conclusões, percebeu-se que o segundo regime apresenta a maior taxa de crescimento no steady state, além de ser mais resiliente a choques negativos.
The general goal of this dissertation is to discuss different dimensions of a class of Post-Keynesian models known as Stock-Flow Consistent Models. The main features of these models are: (i) the presence of balance sheets matrices of the sectors to be modeled, guaranteeing the consistency in the economic stocks; (ii) the flow of funds matrix, that records the real and financial transactions of the economy. The first step of the work is to analyze the origins of the SFC models, presenting the works that preceded the first elaborations. Next to it, the current SFC literature is surveyed. These two steps are accomplished by means of a survey of the literature in academic journals, working papers, dissertations and thesis. The third step of the work is a discussion of methodological issues such as the role of expectations in the behavioral functions for consumption. Finally, the fourth step consists of elaborating a SFC model in order to analyze four fiscal policy regimes: (i) balanced budget, (ii) a target for government’s expenditures , (iii) a target for government deficit, and (iv) a target for government debt. The steady state behavior of each regime is analyzed, as well as its resilience to adverse shocks. The second regime is the one with the higher steady state growth rate and also is the more resilient to negative shocks.

There is evidence that sedentary behaviour and breaks in sedentary time, independent of physical activity levels, influence human health. In order to explore this relationship, accurate and validated measurement instruments are required. Such tools are also required for exploring the effects of factors such as the differences in sedentary behaviour between groups, e.g. overweight/obese vs. healthy weight children. One promising instrument for making such measurements is the activPAL™ monitor. This is an event-based accelerometer with inbuilt inclinometer, and it may be more accurate for the measurement of sitting time and breaks in sitting than earlier instruments. An important setting in the monitor depends on the time required to define a new posture – the minimum sitting/upright period (MSUP). At present, the optimum activPAL™ MSUP setting is not known, particularly for children, who are likely to change posture faster than adults. This thesis includes four studies: Study 1 (Chapter 3): Using the activPAL™, we investigated the effect of variations in MSUP on total sitting time and breaks in sitting. Methods: Study 1a: In this in vitro experiment, the activPAL™ monitor was turned from a horizontal position to a vertical position manually (by hand) to simulate 5 sitting bouts. The length of the sitting time was varied from 1s to 10s. The number of the true events (i.e. 50) and the data from the activPAL™ (the number of sitting bouts for each bout length) was compared and represented in a graph. Study 1b: in data collected from children in a free-living environment (23 children (mean (SD) age 4.5yrs (0.7)) who wore the activPAL™ (24 hr/d) for 5-7d), we varied the setting of the MSUP. For each child, we calculated the following measures of sitting behaviour: volume (total time in sit/lie postures); number of breaks (number of sit/lie to stand transitions); number of sitting bouts (number of discrete periods spent sitting/lying); and pattern of accumulation of sitting (represented by accumulation curves and fragmentation index). We first studied the activPAL™ using the default setting of 10s MSUP, and then reduced this to 5s, 2s, and 1s. Results: Study 1a: the analysis software did not count sitting bouts of a shorter duration than the user defined MSUP in the new posture. For example, the sitting bouts with a period less than 10s were not counted when we used the activPAL™ setting of 10s MSUP. Study 1b: Comparing settings of 10, 5, 2, and 1s, there were no significant differences in total sitting time (6.2 hr (1.0), 6.3 hr (1.0), 6.4 hr (1.0), and 6.3 hr (1.6), respectively) between settings, but there were significant increases in: the apparent number of breaks - 8(3), 14(2), 21(4), and 28 (6)/hr) total number of bouts (118(18) vs 382 (80)); and Fragmentation Index (19.3 (3.7) vs 61.6 (16.4)), with a reduction in 50% bout length from 80s (14.7) to 42s (7.7) at 10s and 1s setting, respectively. Conclusion: With the activPAL™, breaks in sitting, but not total sitting time, are highly sensitive to the setting of the MSUP. Additional studies will be required to confirm these findings and to define the most appropriate MSUP for different age groups. Simple measures can characterise sitting behaviour in young children using the activPAL™. Study 2 (Chapter 4): Posture transitions are likely to be much more rapid in young children than in adults. We investigated the optimum activPAL™ setting of MSUP to define a change in posture for measurement of sitting time and breaks in sitting (not previously known). We evaluated the validity of different minimum event duration settings against direct observation as the criterion method. Methods: In a convenience sample of 30 pre-school children (mean age 4.1yrs (SD 0.5)), we validated the activPAL™ measures of sitting time and breaks in sitting at different MSUP settings against direct observation. Results: In comparison with direct observation, a 2s setting had the smallest error relative to direct observation (95% limits of agreement: -14 to +17 sitting bouts/hr, mean difference 1.83, p = 0.2). Conclusion: For pre-school children, 2s appears to be an appropriate MSUP to define breaks in sitting using the activPAL™. Study 3 (Chapter 5): The identification of risk factors for obesity is considered key to obesity prevention. Differences in time sitting compared to standing have been observed in obese and non-obese adults. Whether such differences are present between obese and non-obese children has not yet been examined. In a pilot study, we investigated differences in sitting behaviour between overweight/obese and healthy weight children. Methods: Overweight/obese children were recruited from weight management and dietetic clinics, the Active Children Eating Smart programme, and from three primary schools, while healthy weight children were recruited from schools. The participants wore the activPAL™ (24 hr/d) for 5-7d. During waking time, the time spent sitting, number of sitting bouts, the 50% and 90% sitting bouts length, and the Fragmentation Index were measured in both groups using the activPAL™ with a 2s MSUP setting. Results were available for 26 healthy weight children (mean age 6.4yrs (SD 0.9), median BMI Z-score 0.04 (range -3.24 - 0.66)) and 13 overweight/obese children (mean age 6.4 yrs (SD 0.9), median BMI Z-score of 1.38 (range 1.14 - 3.10). Results: In healthy weight children during the waking hours, the mean (SD) percentage of waking time spent sitting was 53.0 % (6.4) representing 6.8 hrs (0.9) per day; mean (SD) total number of sitting bouts per day was 280 (65). The median (range) of 50% and 90% of sitting bouts were ≤50.0s (40.0-50.0) and ≤3.5 min (2.0-6.0), respectively. The mean (SD) Fragmentation Index was 42.1(12.7). In the 13 overweight/obese children, the mean (SD) percentage of waking time spent sitting was 52.4% (5.2), representing 6.9 hrs per day (SD 0.8). The total number of sitting bouts was 284 per day (66). The median (range) of 50% and 90% of sitting bouts length were ≤50.0s (40.0-50.0) and ≤3.5 min (3.0-6.0), respectively. The mean (SD) Fragmentation Index was 41.5 (9.6). Conclusion: Both healthy weight children and overweight/obese children in this study spent the majority of their waking time sitting. Furthermore, there were no significant difference in the sitting time, number, or duration of sitting bouts and the Fragmentation Index between the two groups in this study. Study 4 (Chapter 6): Previous studies have shown differences in the total sedentary time between boys and girls using accelerometers where sedentary behaviour was defined as low movement or low energy expenditure. In the present study, we examined whether there were also differences in breaks in sitting time. Methods: A convenience sample of 62 (32 girls: 30 boys) free-living healthy children (mean age 5.8yrs (SD1.3)) was recruited from nurseries and schools in Glasgow and Edinburgh, Scotland, who each wore the activPAL™ monitor continuously for 5–7 days. For each child, the components of sedentary behaviour were measured. Results: The percentage of waking time spent sitting was significantly higher in girls, the mean (SD) (54.4% (5.6)) compared to boys (50.9 (5.6)), (2-sample t-test, p-value <0.02). The total sitting time in girls vs. boys respectively per day was 6.9 (0.8) vs. (6.5) (0.9), (p-value <0.08). There were no significant differences in the number of sitting bouts, Fragmentation Index, or in 50% and 90% sitting bout length between girls and boys. Conclusion: This study suggested that girls spend more time in sitting than boys. However, there were no significant gender differences in the number or duration of sitting bouts. Summary Conclusion: These studies have validated the activPAL™ as an instrument for measuring breaks in sedentary time in young children, and have established appropriate settings for making accurate measurements in this age group. Using these monitors to explore differences between obese and non-obese children, and between boys and girls, we found that, while there were differences between boys and girls in the total sitting time, there were no differences in the number of breaks between girls and boys, or between obese and non-obese children. These studies suggest that the activPAL™ may be useful to identify between group differences in sitting time and sitting fragmentation in future studies.

Thesis (Ph. D.)--School of Education and Dept. of Mathematics and Statistics. University of Missouri--Kansas City, 2006.
"A dissertation in education and mathematics and statistics." Advisor: Tamera B. Murdock. Typescript. Vita. Description based on contents viewed Jan. 29, 2007; title from "catalog record" of the print edition. Includes bibliographical references (leaves 165-172). Online version of the print edition.

Thesis (MPhil)--Stellenbosch University, 2004.
ENGLISH ABSTRACT: Evaluating small business development policies and programmes is a methodologically difficult task. A wide range of role players in the economy - government departments and agencies, corporations, international donors, and non-governmental organisations - invest resources of sizeable magnitude annually in promoting small business. This investment is often justified on the basis of the importance of small business in contributing to the attainment of a range of socio-economic objectives such as job creation, addressing economic inequity among various population groups, stimulating competition in the economy, and enhancing economic growth. With the increase in the magnitude of public investment in small business development, and increasing competition for the same resources from other worthwhile interventions, the pressure for public accountability and the need to demonstrate effectiveness of policies and programmes has increased. Programme sponsors are increasingly requiring that those receiving public funds for small business development projects should ensure effective monitoring and evaluation of their programmes in order to ensure that there is a sound information base to provide the necessary policy and programme feedback. The question, however, is to what extent small business policies and programmes are successful in ensuring the attainment of their objectives. To what degree can any changes at the level of the enterprise and its immediate environment be realistically attributed to the effectiveness of policies and programmes? Can ongoing investment In small business development be justified in the face of competing demands for the same resources from other worthwhile and perhaps more pressing causes? How efficient is a particular policy or programme in terms of its cost in relation to other policy or programme alternatives? These and more are questions facing evaluators of small business development policies and programmes. This thesis shows that the task facing these evaluators is not an easy one, due to methodological complexities encountered in attempting to answer these questions.
AFRIKAANSE OPSOMMING: Die evaluering van ontwikkelingsbeleidsrigtinge en -programme van kleinsakeondernemings is metodologies geen maklike taak nie. 'n Groot verskeidenheid rolspelers in die ekonomie, ingeslote regeringsdepartemente en -instansies, korporasies, internasionale skenkers en nie-regeringsorganisasies, belê jaarliks aansienlike hulpbronne in die bevordering van kleinsakeondernemings. Sodanige beleggings word dikwels geregverdig aan die hand van die belangrikheid van kleinsakeondernemings se bydrae tot die bereiking van verskeie sosio-ekonomiese doelwitte soos werkskepping, en om die kwessie van ekonomiese ongelykheid tussen onderskeie bevolkingsgroepe aan te roer, om mededinging binne die ekonomie aan te moedig en om ekonomiese groei te versterk. Die toename in die omvang van openbare beleggings in kleinsakeontwikkeling asook toenemende mededinging vir dieselfde hulpbronne deur ander verdienstelike partye gaan gepaard met toenemende druk vir openbare aanspreeklikheid en noodsaak doeltreffende beleidsrigtingr en -programme. Programborge vereis toenemend dat diegene wat openbare fondse vir kleinsakeontwikkelingsprojekte ontvang, die doeltreffende monitering en evaluering van hulle programme moet waarborg sodat daar 'n deeglike inligtingsbasis bestaan om die nodige beleids- en programterugvoer te verskaf. Die vraag is egter tot welke mate kleinsakebeleidsrigtinge en -programme daarin slaag om te verseker dat hul doelwitte bereik word. Tot watter mate kan enige veranderinge op ondernemingsvlak en sy onmiddellike omgewing, realisties gesproke, aan die doeltreffendheid van beleidsrigtinge en -programme toegeskryfword? Kan voortgesette beleggings in kleinsakeontwikkeling geregverdig word in die lig van mededinging vir dieselfde hulpbronne deur ander verdienstelike, en moontlik selfs meer dwingende, sake? Hoe doeltreffend is 'n bepaalde beleid of program in terme van sy koste, gesien in verhouding tot ander beleids- of programkeuses? Diegene, wat verantwoordelik is vir die beoordeling van kleinsakeontwikkelingsbeleidsrigtinge en - programme word deur hierdie en vele ander vrae gekonfronteer. Hierdie tesis toon aan dat sodanige beoordelaars, as gevolg van die metodologiese ingewikkeldhede waarvoor hulle te staan kom in die poging om hierdie vrae te beantwoord, geen maklike taak het me.

Significant global health attention and promotion has been focused on hand washing with soap due to the clear benefits observed in promoting and ensuring child health. However, the measurement and evaluation of hand washing behaviours remains complex. The Sanitation, Hygiene Education and Water Supply in Bangladesh Programme (SHEWA-B) is a large project being implemented by the Government of Bangladesh and UNICEF. This research assessed methodological issues of measuring hand washing behaviours through comparison of structured observation and responses to cross-sectional survey measures (spot-check observation, selfreported hand washing and a hand washing demonstration) and discusses the suitability of indicators. Focus group discussions with fieldworkers were also conducted. The results of this study indicate that hand washing behaviours were over-reported compared with structured observation findings. This implies that current estimates of hand washing from large scale surveys, for example, Demographic and Health Surveys (DHS) are also likely to be overestimates. In about 1000 households, approximately 1% or less of female caregivers were observed to wash their hands with soap or ash before preparing food, before eating, and 3% before feeding a child. Hand washing with soap was higher for defecation related events with approximately 29% of female caregivers using soap two thirds or more of the time after cleaning a child’s anus/disposing of a child’s stools and 38% used soap two-thirds or more of the time after defecation. Soap was observed at the hand washing location in about 50% of the households but actual practice was much lower. Reported knowledge was high; approximately 90% identified the important times for hand washing as being before eating and after defecation and approximately 50% identified before preparing food and after cleaning/changing a baby. The measurement of hand washing is complex and there has been limited research into the validity of different measurement methods. This research used an epidemiological style approach using the concepts of screening/diagnostic testing and calculation of kappa statistics to assess validity. In conclusion, this research demonstrates that self report hand washing measures are subject to over reporting. Structured observation provides useful information on directly observed hand washing behaviours and the frequency of behaviours. Spot check methods of soap and hand washing locations also provide more optimistic data than observations and can be used as an alternative to structured observation. In addition, the use of questions on the 24 hour recall of soap and other self report questions on knowledge and the availability of spare soap demonstrate potential for use as potential indicators as an alternative to structured observation. Further validation of measurement methods is required in different country settings.

Capturing life as it is lived is an important goal in psychology, and diary methods are commonly used for this purpose. They capture events near the time of their occurrence and are less prone to retrospective biases associated with questionnaire, interview and survey methods. However, participants in diary studies must remember to carry the diary with them, and find it convenient to make entries in timely fashion. New approaches, replacing paper diaries with technology (e.g. personal digital assistants), can overcome forgetting to make entries and retrospective filling of data. However, until recently technology had its own problems (e.g. unreliability and cost of devices, the need for training, biases of technical competence, etc.). The research described in this dissertation arose from the anticipation that the rapid, worldwide growth of smartphone ownership would overcome many of these limitations since participant-owned smartphone diaries can eliminate associated costs and facilitate increased rates of compliance. Six diary studies were conducted on two transient cognitive phenomena. Initially, a smartphone app was developed and compared with a paper diary in the study of involuntary autobiographical memories. Although participants in the smartphone-diary condition demonstrated significantly better compliance than those in the paper-diary condition by reliably carrying their smartphones, and promptly completing diary entries in the app, they recorded significantly fewer events than paper diary users. To test that this unexpected finding was not specific to involuntary autobiographical memories, the method was tested with everyday memory failures, and the same unexpected finding was obtained. Further studies manipulated the length of diary-keeping period and demonstrated a diary entry rate reduction effect with longer diary keeping periods, an effect seen in both paper- and participant-owned smartphone-diaries. For involuntary autobiographical memories, the effect was demonstrated by comparing 1-day and 7-day diaries, and also by using a 30-40 minutelong digital audio recording method. With everyday memory failures, the effect was demonstrated by comparing 7-day and 28-day diaries. The audio recording method was used to capture involuntary autobiographical memories while driving. It was also used on a campus walk and compared with a 1-day paper diary within-subjects, finding a higher rate of recording in the shorter period, and consistency of memory counts across two modes of recording. This novel audio-recording method facilitated much more detailed analysis of involuntary memory cues and chaining and enabled the evaluation of potential instances of priming. Finally, a telephone and postal-based diary study of everyday memory failures demonstrated the feasibility of recruitment and measurement of participants remotely, which can be particularly useful with older adults. Taken together, the results of this research make a significant methodological contribution to research on transient everyday cognitive phenomena by showing that (1) care is needed when using participant-owned smartphone diaries, (2) paper diaries may be more reliable than currently given credit, and (3) diary-recording periods can be substantially reduced without compromising the quantity and the quality of data obtained. In addition, results increase our theoretical understanding of two specific phenomena studied in this dissertation: involuntary autobiographical memories and everyday memory failures. The findings indicate that involuntary memories are much more frequent than previously thought, may represent a stable characteristic of a person and, in addition to immediately present cues, can be elicited by internal memory chaining process and more distant priming of events and thoughts. Finally, the absence of age effects in the frequency and nature of recorded everyday memory failures, together with significant negative age effects in laboratory tests of memory and cognition, is a novel finding that has significant implications for research on cognitive ageing.

Diet Induced Thermogenesis (DIT) is the energy expended consequent to meal consumption, and reflects the energy required for the processing and digestion of food consumed throughout each day. Although DIT is the total energy expended across a day in digestive processes to a number of meals, most studies measure thermogenesis in response to a single meal (Meal Induced Thermogenesis: MIT) as a representation of an individual’s thermogenic response to acute food ingestion. As a component of energy expenditure, DIT may have a contributing role in weight gain and weight loss. While the evidence is inconsistent, research has tended to reveal a suppressed MIT response in obese compared to lean individuals, which identifies individuals with an efficient storage of food energy, hence a greater tendency for weight gain. Appetite is another factor regulating body weight through its influence on energy intake. Preliminary research has shown a potential link between MIT and postprandial appetite as both are responses to food ingestion and have a similar response dependent upon the macronutrient content of food. There is a growing interest in understanding how both MIT and appetite are modified with changes in diet, activity levels and body size. However, the findings from MIT research have been highly inconsistent, potentially due to the vastly divergent protocols used for its measurement. Therefore, the main theme of this thesis was firstly, to address some of the methodological issues associated with measuring MIT. Additionally this thesis aimed to measure postprandial appetite simultaneously to MIT to test for any relationships between these meal-induced variables and to assess changes that occur in MIT and postprandial appetite during periods of energy restriction (ER) and following weight loss. Two separate studies were conducted to achieve these aims. Based on the increasing prevalence of obesity, it is important to develop accurate methodologies for measuring the components potentially contributing to its development and to understand the variability within these variables. Therefore, the aim of Study One was to establish a protocol for measuring the thermogenic response to a single test meal (MIT), as a representation of DIT across a day. This was done by determining the reproducibility of MIT with a continuous measurement protocol and determining the effect of measurement duration. The benefit of a fixed resting metabolic rate (RMR), which is a single measure of RMR used to calculate each subsequent measure of MIT, compared to separate baseline RMRs, which are separate measures of RMR measured immediately prior to each MIT test meal to calculate each measure of MIT, was also assessed to determine the method with greater reproducibility. Subsidiary aims were to measure postprandial appetite simultaneously to MIT, to determine its reproducibility between days and to assess potential relationships between these two variables. Ten healthy individuals (5 males, 5 females, age = 30.2 ± 7.6 years, BMI = 22.3 ± 1.9 kg/m2, %Fat Mass = 27.6 ± 5.9%) undertook three testing sessions within a 1-4 week time period. During the first visit, participants had their body composition measured using DXA for descriptive purposes, then had an initial 30-minute measure of RMR to familiarise them with the testing and to be used as a fixed baseline for calculating MIT. During the second and third testing sessions, MIT was measured. Measures of RMR and MIT were undertaken using a metabolic cart with a ventilated hood to measure energy expenditure via indirect calorimetry with participants in a semi-reclined position. The procedure on each MIT test day was: 1) a baseline RMR measured for 30 minutes, 2) a 15-minute break in the measure to consume a standard 576 kcal breakfast (54.3% CHO, 14.3% PRO, 31.4% FAT), comprising muesli, milk toast, butter, jam and juice, and 3) six hours of measuring MIT with two, ten-minute breaks at 3 and 4.5 hours for participants to visit the bathroom. On the MIT test days, pre and post breakfast then at 45-minute intervals, participants rated their subjective appetite, alertness and comfort on visual analogue scales (VAS). Prior to each test, participants were required to be fasted for 12 hours, and have undertaken no high intensity physical activity for the previous 48 hours. Despite no significant group changes in the MIT response between days, individual variability was high with an average between-day CV of 33%, which was not significantly improved by the use of a fixed RMR to 31%. The 95% limits of agreements which ranged from 9.9% of energy intake (%EI) to -10.7%EI with the baseline RMRs and between 9.6%EI to -12.4%EI with the fixed RMR, indicated very large changes relative to the size of the average MIT response (MIT 1: 8.4%EI, 13.3%EI; MIT 2: 8.8%EI, 14.7%EI; baseline and fixed RMRs respectively). After just three hours, the between-day CV with the baseline RMR was 26%, which may indicate an enhanced MIT reproducibility with shorter measurement durations. On average, 76, 89, and 96% of the six-hour MIT response was completed within three, four and five hours, respectively. Strong correlations were found between MIT at each of these time points and the total six-hour MIT (range for correlations r = 0.990 to 0.998; P < 0.01). The reproducibility of the proportion of the six-hour MIT completed at 3, 4 and 5 hours was reproducible (between-day CVs ≤ 8.5%). This indicated the suitability to use shorter durations on repeated occasions and a similar percent of the total response to be completed. There was a lack of strong evidence of any relationship between the magnitude of the MIT response and subjective postprandial appetite. Given a six-hour protocol places a considerable burden on participants, these results suggests that a post-meal measurement period of only three hours is sufficient to produce valid information on the metabolic response to a meal. However while there was no mean change in MIT between test days, individual variability was large. Further research is required to better understand which factors best explain the between-day variability in this physiological measure. With such a high prevalence of obesity, dieting has become a necessity to reduce body weight. However, during periods of ER, metabolic and appetite adaptations can occur which may impede weight loss. Understanding how metabolic and appetite factors change during ER and weight loss is important for designing optimal weight loss protocols. The purpose of Study Two was to measure the changes in the MIT response and subjective postprandial appetite during either continuous (CONT) or intermittent (INT) ER and following post diet energy balance (post-diet EB). Thirty-six obese male participants were randomly assigned to either the CONT (Age = 38.6 ± 7.0 years, weight = 109.8 ± 9.2 kg, % fat mass = 38.2 ± 5.2%) or INT diet groups (Age = 39.1 ± 9.1 years, weight = 107.1 ± 12.5 kg, % fat mass = 39.6 ± 6.8%). The study was divided into three phases: a four-week baseline (BL) phase where participants were provided with a diet to maintain body weight, an ER phase lasting either 16 (CONT) or 30 (INT) weeks, where participants were provided with a diet which supplied 67% of their energy balance requirements to induce weight loss and an eight-week post-diet EB phase, providing a diet to maintain body weight post weight loss. The INT ER phase was delivered as eight, two-week blocks of ER interspersed with two-week blocks designed to achieve weight maintenance. Energy requirements for each phase were predicted based on measured RMR, and adjusted throughout the study to account for changes in RMR. All participants completed MIT and appetite tests during BL and the ER phase. Nine CONT and 15 INT participants completed the post-diet EB MIT and 14 INT and 15 CONT participants completed the post-diet EB appetite tests. The MIT test day protocol was as follows: 1) a baseline RMR measured for 30 minutes, 2) a 15-minute break in the measure to consume a standard breakfast meal (874 kcal, 53.3% CHO, 14.5% PRO, 32.2% FAT), and 3) three hours of measuring MIT. MIT was calculated as the energy expenditure above the pre-meal RMR. Appetite test days were undertaken on a separate day using the same 576 kcal breakfast used in Study One. VAS were used to assess appetite pre and post breakfast, at one hour post breakfast then a further three times at 45-minute intervals. Appetite ratings were calculated for hunger and fullness as both the intra-meal change in appetite and the AUC. The three-hour MIT response at BL, ER and post-diet EB respectively were 5.4 ± 1.4%EI, 5.1 ± 1.3%EI and 5.0 ± 0.8%EI for the CONT group and 4.4 ± 1.0%EI, 4.7 ± 1.0%EI and 4.8 ± 0.8%EI for the INT group. Compared to BL, neither group had significant changes in their MIT response during ER or post-diet EB. There were no significant time by group interactions (p = 0.17) indicating a similar response to ER and post-diet EB in both groups. Contrary to what was hypothesised, there was a significant increase in postprandial AUC fullness in response to ER in both groups (p < 0.05). However, there were no significant changes in any of the other postprandial hunger or fullness variables. Despite no changes in MIT in both the CONT or INT group in response to ER or post-diet EB and only a minor increase in postprandial AUC fullness, the individual changes in MIT and postprandial appetite in response to ER were large. However those with the greatest MIT changes did not have the greatest changes in postprandial appetite. This study shows that postprandial appetite and MIT are unlikely to be altered during ER and are unlikely to hinder weight loss. Additionally, there were no changes in MIT in response to weight loss, indicating that body weight did not influence the magnitude of the MIT response. There were large individual changes in both variables, however further research is required to determine whether these changes were real compensatory changes to ER or simply between-day variation. Overall, the results of this thesis add to the current literature by showing the large variability of continuous MIT measurements, which make it difficult to compare MIT between groups and in response to diet interventions. This thesis was able to provide evidence to suggest that shorter measures may provide equally valid information about the total MIT response and can therefore be utilised in future research in order to reduce the burden of long measurements durations. This thesis indicates that MIT and postprandial subjective appetite are most likely independent of each other. This thesis also shows that, on average, energy restriction was not associated with compensatory changes in MIT and postprandial appetite that would have impeded weight loss. However, the large inter-individual variability supports the need to examine individual responses in more detail.

The thesis investigates the dynamics that surround participants' responses to questions about illicit drug activities. By examining the attributional and discursive literatures, the opening chapters (Chapters 1 and 2) outline the difficulties associated with assuming veridicality in question-answer dyads. Emphasis is placed on the essentially social and intentional foundations of the applied research procedure. The existing research on methodological effects in substance research is outlined at the start of Chapter 3. These form the foundation for the empirical investigations that constitute the remainder of the thesis. The studies carried out attempt to examine methodological issues in the context of applied research procedures that combine quantitative outcomes with qualitative considerations such as reflexive consideration of the role of the researcher and the status of the participant. The first investigation demonstrates the influence of treatment status on the discourse provided by adult substance users. Drug users in contact with treatment services provide drug-related explanations distinct from those given by users who are not in treatment. This distinction is assessed in terms of a theoretical model of addiction based on discursive criteria and contextual influence (Chapter 4). These contextual influences are further examined in the empirical studies presented in Chapters 4 and 5 in which the subjects are young people whose drug experiences are assessed in the context of drug education (Chapter 5) and treatment and service needs (Chapter 6). Each of these investigations attempts to demonstrate the sophistication of discourse that respondents exhibit in their drug-related conversations and the ways in which their attitudes and understandings of these topics are shaped by the context of the experiences they have had.