The development of a methodology to improve the parametric representation of the failure criteria used to characterize rock strength of a reservoir rock in the near-wellbore region is the focus of this study. We adopted a statistical method, so-called error-in-variables (EIV), to take into account experimental errors in all of the measured variables. The proposed methodology is employed to obtain the parameters of the failure envelope (2D criteria) from experimental data in the following cases: When the experimental data are used directly to determine the failure envelope in the Mohr plane. When a failure envelope is first obtained in the principal-stress plane and then transformed into the Mohr plane using Computer Algebra. When the presence of pore fluid requires the consideration of effective stresses. When the brittle-ductile transition requires special form of the envelope (cap models) Using generalization of previously developed methods, we employed EIV methods to obtain the parameters of a failure surface in the principal-stress space (3D criteria).The basic hypothesis of this work is that the EIV method provides a better representation of failure criteria than the previous methodology. The basic application of any failure criterion is to determine whether a certain stress state will or will not lead to failure. A parametric representation is considered better than another if the likelihood of obtaining the wrong answer is less than in the other case. Therefore, the best representation (within a certain family of envelopes or surfaces) is the one minimizing the objective function, which is nothing else but the likelihood of this wrong answer. To test the basic hypothesis of this work, I compared the objective function (likelihood of erroneous decision) calculated with parametric representations obtained by various methods. To achieve this I evaluated a well-documented, published set of experimental data, for which failure envelopes have been fitted by other methods. This work is limited to the processing of data obtained in experiments conducted in homogenous, isotropic rock at isothermal conditions. Sedimentary rocks such as sandstone are the focus of this study because of their importance in near-wellbore reservoir rock stability problems. Nevertheless, the methodology developed in this work is not limited to this type of rock.

BACKGROUND: Acute renal failure (ARF) is a clinical syndrome characterised by a rapid deterioration of kidney function over hours to days which may recover/return to normal values following appropriate therapy. Various scoring systems currently exist to predict the severity and outcome in patients with ARF. Recently the Acute Dialysis Quality Initiative (ADQI) Group has established the RIFLE (Risk of injury, Injury to the kidney, Failure of kidney function, Loss of kidney function, and End-stage kidney disease) classification which has become widely used globally. There is however, limited data on its use in Africa. In order to provide data on the use of RIFLE criteria from an African facility, we conducted a retrospective chart review to assess the outcome of ARF in patients admitted in the Intensive Care Unit (ICU) at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH). The data reviewed covered the period between January 1st to December 31st 2008. METHODS: This was a retrospective chart review conducted in the adult multi-disciplinary intensive care unit at CMJAH between January 1st to December 31st 2008. Medical records of patients admitted during this period were reviewed and patients with acute renal failure were identified. Demographic data, relevant clinical information such as reason for ICU admission, number of organ(s) involved, presence of co-morbidity, RIFLE criteria on admission and on discharge, modality and duration of treatment of ARF, need for mechanical ventilation and or inotropic support were recorded. For the purpose of this study, serum creatinine based on RIFLE classification was used to define ARF. Statistical analysis was performed using the data collected and STATA version 11. The Primary outcome, which was survival or death, was correlated with the maximum RIFLE classification during patients’ ICU stay. The study was approved by the Human Research Ethics Committee medical (HRECM) of the University of Witwatersrand with Clearance certificate number M090906 RESULTS: One hundred and ninety three (193) patients with acute renal failure were included in the study. The mean APACHE II score was 19 ± 6.4 SD, with the maximum score documented being 38. Patient ages ranged from 21 – 92 years with a mean of 50.5 years ± 18.3SD. Fifty two percent of the patients were male and 48% were female. Majority of patients were black (63%) with 36.8% being other race groups. According to RIFLE criteria on admission, 40.9% had normal renal function, 23.3%, 14.0% and 21.8% were in RIFLE R, I and F classes respectively. The overall mortality in ICU was 59.9%. Of those patients discharged to the ward from ICU, 14.1% subsequently demised. Factors associated with mortality in ICU included race, chronic pulmonary disease, mechanical ventilation, inotropic support, need for ventilation and inotropic support, dialysis and maximum RIFLE criteria reached in ICU. After multivariate analysis using Cox proportion regression model, factors such as race, inotropic support, need for both ventilation and inotropic support and maximum RIFLE criteria were independently associated with mortality in ICU, whereas for patients discharged from ICU to the ward, only cancer was found to be independently associated with mortality. Based on RIFLE criteria, patients in R, I, and F class had 5.41, 3.17 and 5.69 greater risk of dying respectively as compared to patients with normal renal function (Adjusted HR 5.41 95%CI 2.66 - 11.0, p-Value 0.000 for R class, HR 3.17 95%CI 1.65 - 6.07, p-value 0.001for I class, and HR 5.69 95%CI 2.93 - 11.06, p-value 0.001 for F class) CONCLUSION: RIFLE criteria is a useful tool for predicting the outcome of acute renal failure in the intensive care unit.

Something is Missing is an installation that incorporates drawing, a security camera, audio, appropriated objects and built sculptural elements using common construction materials and clay. This work is rooted in notions of failure and empathy. Drawings of organs float as if desperate to inhabit imaginary bodies, a security camera that resembles an examining tool of a medical practitioner fails to fix or function and walls fall short of completing a room. This room as a whole becomes a metaphor for a stage without actors. The thesis body of work that comprises Something is Missing is a meant to serve as what I call a dysfunctional affect machine that opens cross-sensory possibilities and induces empathetic feelings in the viewer. The aim of this machine is to pose questions rather than suggest answers to the contemporary predicament of being bodies in a post human era. This work is also meant to summarize a sort of contemporary anxiety, which I feel I participate in both as an artist and citizen of the World.

No description available.

Thesis (MHSc--Health Science) -- Auckland University of Technology, 2004. / Also held in print (170 leaves, 30 cm.) in Akoranga Theses Collection (T 362.19612900993 MUN)

Thesis (Ph. D.)--Columbia University, 1927. / Vita. Bibliography: p. 52-55.

Thesis--University of Pennsylvania. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1983. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 223-238).

Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Outcome of HIV positive patients presenting with renal failure at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) Background The majority of the 33.4 million people infected with HIV worldwide reside in sub-Saharan Africa. The HIV prevalence amongst young South Africans (ages 15- 49) is 16%. HIV is the third leading cause of ESRD in African - Americans aged 20-64 in the United States. There is a paucity of data regarding the prevalence of acute kidney injury (AKI) in HIV patients in sub-Saharan Africa. Methods A retrospective review of 101 HIV positive patients presenting with renal failure at the CMJAH from 1st October 2005 until 31st October 2006 was undertaken. There were 50 HIV positive patients with presumed AKI that were compared to 90 HIV negative patients with AKI. Results A total of 684 patients presented with renal failure, 101(14.8%) of whom were HIV positive. Ninetynine of the HIV positive patients were black and 56 were male. The mean age of HIV positive patients with renal failure was 38 years. Fifty-seven patients presented with AKI (seven patients were excluded due to lack of records), 21 with acute on chronic renal failure and 23 with chronic renal failure. The causes of AKI in the HIV positive group included sepsis (62%), haemodynamic instability (20%), toxins (10%), urological obstruction (8%) and miscellaneous (10%). The common underlying aetiologies of the 90 HIV negative patients studied presenting with AKI were sepsis (43%), haemodynamic instability (17%), toxins (7%), urological obstruction (8%) and miscellaneous (23%). Forty-seven (52%) of these HIV negative patients recovered. Forty-two (47%) patients died, compared with 22 (44%) patients in the HIV positive group. Hyponatraemia, hyperkalaemia, hypochloraemia and acidosis were more common in the HIV positive patients. Dialysis was initiated in 36% of HIV positive patients with AKI. There were more HIV positive patients that recovered with supportive care, including fluid therapy when compared to HIV negative patients. Recovery was noted to be more rapid in the HIV positive group. Using survival and death as the outcome there was no difference between the HIV positive and the HIV negative group presenting with AKI (p<0.7173). Discussion HIV positive patients presented with renal failure at a younger age – a mean age of 38 years in this study. Previous studies have shown mean ages ranging from 35 years to 46.7 years. The majority of the HIV positive patients presenting with renal failure were black (98%). The racial predominance is different to that of other countries which might be due to epidemiological factors. The gender differences were similar when compared to other studies. Sepsis was the more common aetiological factor of AKI (62% of HIV positive patients compared to 43% of HIV negative patients). HIV positive patients with AKI presented at an advanced stage of immunosuppression (more than 50% had CD4<100cells/μl). Electrolyte disturbances were common in HIV positive patients with AKI. Conclusion HIV positive patients with AKI presented with advanced immunosuppression. Sepsis was the most common aetiology of AKI. Supportive management or renal replacement therapy resulted in recovery in a large number of patients.HIV positive patients should be treated acutely just as HIV negative patients and should not be excluded on the basis of their HIV status. Dialysis should be offered when indicated and aggressive fluid resuscitation should be emphasized. Outcomes were similar in HIV positive and HIV negative patients presenting with AKI.