Chapter 1 gives a brief introduction to statistical quality control (SQC) and provides background information regarding the research conducted in this thesis. We begin Chapter 2 with the design of Shewhart-type Phase I S2, S and R control charts for the situation when the mean and the variance are both unknown and are estimated on the basis of m independent rational subgroups each of size n available from a normally distributed process. The derivations recognize that in Phase I (with unknown parameters) the signaling events are dependent and that more than one comparison is made against the same estimated limits simultaneously; this leads to working with the joint distribution of a set of dependent random variables. Using intensive computer simulations, tables are provided with the charting constants for each chart for a given false alarm probability. Second an overview of the literature on Phase I parametric control charts for univariate variables data is given assuming that the form of the underlying continuous distribution is known. The overview presents the current state of the art and what challenges still remain. It is pointed out that, because the Phase I signaling events are dependent and multiple signaling events are to be dealt with simultaneously (in making an in-control or not-in-control decision), the joint distribution of the charting statistics needs to be used and the recommendation is to control the probability of at least one false alarm while setting up the charts. In Chapter 3 we derive and evaluate expressions for the run-length distributions of the Phase II Shewhart-type p-chart and the Phase II Shewhart-type c-chart when the parameters are estimated. We then examine the effect of estimating and on the performance of the p-chart and the c-chart via their run-length distributions and associated characteristics such as the average run-length, the false alarm rate and the probability of a “no-signal”. An exact approach based on the binomial and the Poisson distributions is used to derive expressions for the Phase II run-length distributions and the related Phase II characteristics using expectation by conditioning (see e.g. Chakraborti, (2000)). We first obtain the characteristics of the run-length distributions conditioned on point estimates from Phase I and then find the unconditional characteristics by averaging over the distributions of the point estimators. The in-control and the out-of-control properties of the charts are looked at. The results are used to discuss the appropriateness of the widely followed empirical rules for choosing the size of the Phase I sample used to estimate the unknown parameters; this includes the number of reference samples m and the sample size n. Chapter 4 focuses on distribution-free control charts and considers a new class of nonparametric charts with runs-type signaling rules (i.e. runs of the charting statistics above and below the control limits) for both the scenarios where the percentile of interest of the distribution is known and unknown. In the former situation (or Case K) the charts are based on the sign test statistic and enhance the sign chart proposed by Amin et al. (1995); in the latter scenario (or Case U) the charts are based on the two-sample median test statistic and improve the precedence charts by Chakraborti et al. (2004). A Markov chain approach (see e.g. Fu and Lou, (2003)) is used to derive the run-length distributions, the average run-lengths, the standard deviation of the run-lengths etc. for our runs rule enhanced charts. In some cases, we also draw on the results of the geometric distribution of order k (see e.g. Chapter 2 of Balakrishnan and Koutras, (2002)) to obtain closed form and explicit expressions for the run-length distributions and/or their associated performance characteristics. Tables are provided for implementation of the charts and examples are given to illustrate the application and usefulness of the charts. The in-control and the out-of-control performance of the charts are studied and compared to the existing nonparametric charts using criteria such as the average run-length, the standard deviation of the run-length, the false alarm rate and some percentiles of the run-length, including the median run-length. It is shown that the proposed “runs rules enhanced” sign charts offer more practically desirable in-control average run-lengths and false alarm rates and perform better for some distributions. Chapter 5 wraps up this thesis with a summary of the research carried out and offers concluding remarks concerning unanswered questions and/or future research opportunities. / Thesis (PhD)--University of Pretoria, 2009. / Mathematics and Applied Mathematics / unrestricted

Nurses who work in the intensive care settings (or units, ICU) in Canada encounter a growing number of patients living with obesity (PLWO) in clinical practice. Many authors suggest that the number of PLWO who are admitted to the ICU has increased significantly because obesity is on the rise in Canada. PLWO are thought to be at a higher risk for developing chronic illnesses and life-threatening complications that require an admission to the ICU. They are also more likely to develop postoperative complications that require life-sustaining treatments, invasive hemodynamic monitoring and evaluation, assistive devices, pharmacological interventions, parenteral nutrition, fluid and electrolyte management, and prolonged admission with associated risks of complications. Yet, there is limited research on the experience of nurses providing care to PLWO. The goal of this qualitative study was to examine the experiences of ICU nurses who work with PLWO and how these experiences affect the way they provide care. More specifically, this study was designed to describe and explore the inclusionary and exclusionary practices developed by nurses providing care to PLWO by drawing Canales’ (2000) Othering framework. Lastly, an additional goal of this study was to document the needs of ICU nurses with respect to the care of PLWO and areas of improvement in the ICU. A total of 11 ICU nurses were interviewed for this study. Data analysis followed the principles of Applied Thematic Analysis (ATA) and revealed four themes. The first theme describes how the PLWO become “Other” in the ICU context. The second theme focuses on exclusionary Othering and how it manifests itself in the way PLWO are differentiated, cared for, and viewed in the ICU context. The third theme sheds light on inclusionary Othering in the form of strategies that are used by ICU nurses to engage with PLWO in a way that is inclusive and transformative. Finally, the last theme concentrates on the ICU environment itself and the resources available (or not available) to nurses, with a particular emphasis on the needs of nurses who provide care to PLWO.

D.Cur. / Intensive nursing science in the Republic of South Africa has become so comprehensive and has gained momentum to such an extent the curriculum for the diploma in intensive nursing science no longer suffices. This study has attempted to identify the scope of intensive care for the professional nurse within the context of the community need for intensive care and to develop the curriculum in accordance. To achieve this purpose a theoretical framework was compiled out of the literature according to which the curriculum was evaluated. The task of the professional nurse in intensive care was identified by means of a literature study, observations and interviews. In addition, a statistical survey was done of the diseases with which the patients are admitted into intensive care units. It is obvious that the prescribed curriculum has, to a large extent achieved its aim but an explicit need was indicated for more training schools and trained professional nurses in intensive care. The evaluation practices for the diploma in intensive nursing science must be placed upon a scientific basis.

M.Cur. / Please refer to full text to view abstract

M.Cur. (General Intensive Nursing) / In South Africa, where the nurse is seen as an independent practitioner, she must take continuously accountability and responsibility for her actions. Only she can decide whether she is legally able, or knowledgeable and competent enough to accept a prescription or direction from a doctor. Once she has indicated acceptance, she has made an independent decision and accepts full responsibility and accountability for her decisions and actions. Accountability means that the nurse must be able to give a reason for her actions and or omissions. It is very important that she has enough knowledge of the effects, side-effects, indications and contra-indications of the medications that are prescribed by the doctor before she administers it. Knowledge of medications and the Nursing Act with related regulations that directs her practice, are very important to the nurse to ensure a high standard of nursing care. The nurse working in an intensive care unit must often make decisions in a crisis situation in connection with her legal accountability. So much more in the private sector where the intensive care nurse must .often rely on her own judgement and knowledge because a doctor is not always available. Two questions evolving from this is what is the nurse's responsibility with in the legal framework of medication administration in a intensive care unit and do nurses have enough knowledge of selected medications? These two questions have been answered by evaluation of the doctor's prescriptions and nursing actions, with the help of prelisted control lists and a questionnaire The results of the study showed that the doctor's prescriptions were not legally correct and nurse's actions and knowledge of the selected medications were not up to the expected standard in the chosen unit. Two recommendations evolving from this study are that inservice training to increase knowledge of medications that are frequently used in the unit should be presented monthly and that more time must be spent on pharmacology during the training of the intensive care nurse.

Introduction : La réanimation est une discipline médicale récente ayant pour spécificité une surveillance rapprochée et tracée des patients et de leurs traitements. Une grande quantité de données concernant les caractéristiques des patients, leur prise en charge et leur évolution sont ainsi générées et collectées quotidiennement. La médecine basée sur les preuves oppose classiquement les études observationnelles et interventionnelles et confère à ces dernières, notamment aux études randomisées et contrôlées, un niveau de preuve scientifique supérieur.Objectifs : Décrire l’apport de l’utilisation des données observationnelles en réanimation au travers de travaux récents recourant à différentes méthodologies d’analyse. Discuter les contributions respectives qu’ont les études observationnelles et interventionnelles dans l’acquisition des connaissances scientifiques en réanimation.Méthode : Quatre études observationnelles prospectives multicentriques conduites en réanimation et publiées dans des revues à comité de relecture. Détail de la variété des outils disponibles dans la conception d’études observationnelles à travers différentes méthodes telles que l’utilisation de données en temps réel, la description de cohortes, et l’appariement sur un score de propension afin d’estimer l’effet d’un traitement. Résultats : Les différents travaux détaillés dans cette thèse décrivent la variété des apports des données observationnelles en réanimation. Ces données peuvent constituer un outil de surveillance des épidémies en temps réel comme nous l’avons montré au cours de la pandémie de grippe A H1N1 en France. Elles sont aussi indispensables à la réalisation d’études épidémiologiques telle celle que nous présentons concernant le syndrome de détresse respiratoire aigu. Nous montrons aussi comment ce type de données a remis en question la définition des groupes de sevrage de la ventilation mécanique initialement proposée par une conférence de consensus. Enfin, l’utilisation de techniques statistiques innovantes telles celles basées sur un score de propension a permis l’évaluation du bénéfice de l’utilisation de la circulation extra-corporelle à visée d’oxygénation dans les cas les plus sévères de détresse respiratoire secondaire à la grippe A H1N1.Conclusion : Les études observationnelles ne sont pas à opposer aux études interventionnelles mais apportent des résultats complémentaires et offrent des solutions alternatives lorsqu’une intervention ne peut pas être testée. Connaitre les avantages et limites de chacune des méthodes permet d’optimiser la conception des études l’interprétation des résultats. L’utilisation des données observationnelles en réanimation participe pleinement au progrès des connaissances de cette spécialité. / Introduction: Intensive care is a recent medical specialty which has the particularity to provide a close monitoring and traceability of patients and their treatments. Thus, a huge amount of data is daily collected on characteristics, management and evolution of patients. Evidence based medicine usually confronts observational and interventional studies confers to the latters, particularly randomized controlled trials, a higher scientific quality.Objective: To describe the benefit of observational data for intensive care through recent works using different analysis methods. To discuss respective benefits of observational and interventional studies for scientific knowledge in intensive care.Methods: Four prospective observational multicenter studies conducted in intensive care units and published in peer reviewed journals. Detail of the spectrum of available tools to design observational studies presenting different methods such as real time data use, cohort description and propensity matched analysis to estimate a treatment effect. Results: The studies presented in this thesis describe the different contributions of observational data for intensive care. As we demonstrated during the Influenza A H1N1 pandemics, observational data can be used for a real-time monitoring of epidemics. They are necessary to conduct epidemiological studies such as the acute respiratory distress syndrome study presented. We also show how observational data lead to question the definition of weaning from mechanical ventilation groups initially proposed by a consensus conference. Finally, innovative statistics techniques as propensity score allowed the evaluation of extracorporeal membrane oxygenation for the most severe cases of respiratory failure due the Influenza A H1N1. Conclusion: Observational studies should not be opposed to interventional studies as they provide additional results and give alternative options when an interventional cannot be tested. One must know the benefits and limits of each methods in order to optimize studies design and results interpretation. Observational data are fully part of the knowledge progress of intensive care specialty.

The hollow curve species abundance distribution describes the pattern of large numbers of rare species and a small number of common species in a community. The species abundance distribution is one of the most ubiquitous patterns in nature and many models have been proposed to explain the mechanisms that generate this pattern. While there have been numerous comparisons of species abundance distribution models, most of these comparisons only use a small subset of available models, focus on a single ecosystem or taxonomic group, and fail to use the most appropriate statistical methods. This makes it difficult to draw general conclusions about which, if any, models provide the best empirical fit to species abundance distributions. I compiled data from the literature to significantly expand the available data for underrepresented taxonomic groups, and combined this with other macroecological datasets to perform comprehensive model comparisons for the species abundance distribution. A multiple model comparison showed that most available models for the species abundance distribution fit the data equivalently well across a diverse array of ecosystems and taxonomic groups. In addition, a targeted comparison of the species abundance distribution predicted by a major ecological theory, the unified neutral theory of biodiversity (neutral theory), against a non-neutral model of species abundance, demonstrates that it is difficult to distinguish between these two classes of theory based on patterns in the species abundance distribution. In concert, these studies call into question the potential for using the species abundance distribution to infer the processes operating in ecological systems.

No description available.

A research dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg in fulfilment of the requirements for the degree of Master of Science in Nursing / Background: South African professional nurses, working in an Intensive Care Unit (ICU) experience many physical and psycho-social hazards and risks. Stress, provoked by failure to meet work demands, leads to illness, injury and psychological suffering. This in turn may result in absenteeism and to the nurse abandoning the profession. It is therefore necessary for healthcare administrators to address the aspects leading to nurse stress and work burnout. Setting: The study was conducted in the adult intensive care units of a public sector hospital. Purpose of the study: The purpose of the study was to develop and pilot test a stress management intervention for professional nurses practising in ICUs. Method: A quasi-experimental non-equivalent control group design was selected for this study. It comprised of pre-testing, development and implementation of the intervention and post testing. Both groups of professional nurses were recruited from the same hospital by means of convenience sampling. Each group was asked to complete the Expanded Nurses Stress Scale (ENSS). The Intervention group participated in the educational intervention on stress management. The control group received no form of any intervention. Both groups completed the ENSS, four weeks after completion of the intervention. The intervention group of participants also completed a stress management intervention assessment form in order to collect feedback for the evaluation of the workshop and the researcher. The quantitative data was analysed by means of descriptive summary statistics. Results: There was clear evidence of significant differences (p=0.000) emerging in all 9 subscale total average scores with respect to level of stress when considering the pre-test score and the post-test score. This indicates the stress management intervention had an effect on the stress levels of nurses practicing in the ICUs at the selected study sites. Evaluation of stress management intervention workshop also revealed that an overwhelming (>87%) number of nurse participants experienced all activities as meaningful, with contributory worth. Recommendations arising from the study findings are put forward for intensive care nursing practice, occupational health nursing, executive hospital management and further research. Key words: intensive care, nurses, stress management intervention. / GR2018

MSc Nursing, Faculty of Health Sciences, University of the Witwatersrand, 2009 / Critically ill patients are particularly vulnerable to pain as a result of the severity of their disease conditions, diagnostic and treatment interventions but pain management is not considered a priority in the Intensive Care Unit (ICU) team (Holden, 1991: Walsh & Ford, 1992). Pain causes complications in the ICU patient, which increases their ICU stay and cost of ICU treatment (Pooler-Lunse & Price, 1992). The purpose of this study was to describe the parameters identified by ICU nurses that can be used to assess pain in the critically ill unconscious patient in the adult Intensive Care Units and whether these parameters are considered by the ICU nurses when managing the unconscious patients’ pain. The objectives of the study were to describe the parameters identified by ICU nurses that can be used for assessing pain in unconscious patients and to determine whether these parameters were considered by ICU nurses when managing the unconscious patient’s pain. A non-experimental, descriptive, prospective, comparative, two part design was used for the study. The sample comprised of ICU nurses (n = 40) in four adult ICU’s and the unconscious patients (n = 40) they nursed. Part one involved the nurses’ responses to a self administered Likert-type questionnaire about parameters that could be indicative of pain in the unconscious patient and part two involved a prospective record review of the unconscious patients ICU charts. A comparison was then done between these two parts to determine if the parameters identified by ICU nurses that could be indicative of pain in the unconscious patient, were considered in their management of the unconscious patients pain. Descriptive statistics were used to analyse data. Of the responses elicited from the questionnaire, ICU nurses agreed that raised blood pressure, pyrexia, increased respiratory rate, dilated pupils and increased heart rate could all be indicative of pain in the unconscious patient but these did not influence their management of the unconscious patient’s pain.