Continuous improvement in the context of organizational culture

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering; and, Thesis (M.S.)--Sloan School of Management, 1996.Includes bibliographical references (p. 114-116).by W. Jaco Smit.M.S

An ‘apples to apples’ comparison of various tests for exponentiality

The exponential distribution is a popular model both in practice and in theoretical work. As a result, a multitude of tests based on varied characterisations have been developed for testing the hypothesis that observed data are realised from this distribution. Many of the recently developed tests contain a tuning parameter, usually appearing in a weight function. In this paper we compare the powers of 20 tests for exponentiality—some containing a tuning parameter and some that do not. To ensure a fair ‘apples to apples’ comparison between each of the tests, we employ a data-dependent choice of the tuning parameter for those tests that contain these parameters. The comparisons are conducted for various samples sizes and for a large number of alternative distributions. The results of the simulation study show that the test with the best overall power performance is the Baringhaus and Henze test, followed closely by the test by Henze and Meintanis; both tests contain a tuning parameter. The score test by Cox and Oakes performs the best among those tests that do not include a tuning parameter.The first author thanks the National Research Foundation of South Africa for financial support.https://link.springer.com/journal/1802018-05-20hj2017Statistic

Distribution of viral antigen in tissues of new-born lambs infected with Rift Valley fever virus

The distribution of Rift Valley fever (RVF) viral antigen was studied by immunohistochemistry in the liver, spleen, prescapular lymph node, lungs and kidneys of eight experimentally infected new-born lambs and in four new-born lambs that died of RVF during the 1974-75 RVF epidemic. The eight experimentally infected lambs were euthanazed at 6, 12, 18, 24, 30, 33, 48 and 51 h post-infection (p.i.), respectively. Immunohistochemical staining utilized polyclonal hyperimmune mouse ascites fluid to RVF virus and peroxidase-diaminobenzidine as substrate. Virus antigen was most prominent in the liver and was detected as early as 18 h p.i. in the cytoplasm of hepatocytes that were sparsely scattered throughout the lobules. At 24-33 h p.i., antigen was also present in or adjacent to small foci of hepatocellular necrosis. At 48-51 h p.i. and in one of the field cases, positive staining was widespread and most consistently present in the cytoplasm of large numbers of degenerated or necrotic hepatocytes and in a few acidophilic bodies. Immunohistochemical staining was rarely observed in hepatocyte nuclei. Almost diffuse histochemical staining was observed in disintegrated cells and in the cytoplasm of necrotic hepatocytes throughout the liver in the other three field cases with pannecrosis; only the primary foci of necrosis and a narrow periportal rim of intact hepatocytes did not stain. No staining was observed in bile duct epithelium, endothelial and Kupffer cells in the initial stages of infection, supporting the contention that hepatocytes constitute the primary site of RVF virus replication in new-born lambs. Few cells stained positively in the spleen, prescapular lymph node, lungs and kidneys.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Application of immunoperoxidase techniques to formalin-fixed brain tissue for the diagnosis of rabies in southern Africa

Two immunoperoxidase techniques, viz. avidin-biotin complex (ABC) and peroxidase-anti-peroxidase (PAP) procedures, were applied to paraffin-wax-embedded brain-tissue sections, from brains which had been fixed in 10% formalin, to demonstrate the presence of rabies-virus antigen by light microscopy. These techniques positively identified both "viverrid" and "canid" rabies-virus antigen in tissue sections of species commonly infected with rabies virus in southern Africa, viz. the domestic dog (Canis familiaris) , yellow mongoose (Cynictus penicillata), black-backed jackal (Canis mesomelas), bat-eared fox (Otocyon megalotus), cattle (Bos taurus), sheep (Ovis aries) and humans. With both of these techniques rabies-virus antigen stained as sharply demarcated, brown precipitates within the cytoplasm of neurons. The virtual absence of background staining enabled identification of fine granules of viral antigen, often referred to as "virus dust", within axons, dendrites and cytoplasm of the nerve cell body. Staining with the ABC procedure produced clearer, more deeply-coloured precipitates than the PAP method.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

The Lymnaea Cardioexcitatory Peptide (LyCEP) Receptor: A G-Protein–Coupled Receptor for a Novel Member of the RFamide Neuropeptide Family

A novel G-protein–coupled receptor (GRL106) resembling neuropeptide Y and tachykinin receptors was cloned from the molluscLymnaea stagnalis. Application of a peptide extract from the Lymnaea brain to Xenopus oocytes expressing GRL106 activated a calcium-dependent chloride channel. Using this response as a bioassay, we purified the ligand for GRL106,Lymnaea cardioexcitatory peptide (LyCEP), an RFamide-type decapeptide (TPHWRPQGRF-NH2) displaying significant similarity to the Achatina cardioexcitatory peptide (ACEP-1) as well as to the recently identified family of mammalian prolactin-releasing peptides. In the Lymnaeabrain, the cells that produce egg-laying hormone are the predominant site of GRL106 gene expression and appear to be innervated by LyCEP-containing fibers. Indeed, LyCEP application transiently hyperpolarizes isolated egg-laying hormone cells. In theLymnaea pericardium, LyCEP-containing fibers end blindly at the pericardial lumen, and the heart is stimulated by LyCEPin vitro. These data confirm that LyCEP is an RFamide ligand for GRL10

The diagnosis of Wesselsbron disease in a new-born lamb by immunohistochemical staining of viral antigen

Wesselsbron disease (WSL) was diagnosed in a 2-d-old lamb on a farm in the north-eastern Free State Province where a few abortions and neonatal deaths occurred in sheep in April 1994. The liver of the lamb was slightly swollen and orange-brown and, microscopically, it revealed single or small groups of necrotic hepatocytes that were randomly scattered throughout the lobules. Other histopathologic hepatic lesions included the presence of acidophilic bodies, intranuclear inclusion bodies in a few hepatocytes, neutrophils in the parenchyma, mild Kupffer-cell and bile-ductular proliferation and infiltration of mixed inflammatory cells in the portal tracts. Immunohistochemical staining of sections of formalin-fixed specimens of the liver with polyclonal antibody against WSL virus revealed positive staining in acidophilic bodies, cytoplasmic fragments of necrotic liver cells, the cytoplasm of degenerated hepatocytes and, rarely, in intranuclear inclusions. Positive staining was also obtained in liver sections from two newborn lambs experimentally infected with WSL virus. The results of this investigation showed that the immunohistochemical staining of sections of formalin-fixed liver can be used to confirm the diagnosis of WSL in new-born lambs.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Sediment Transport of Fine Sand to Fine Gravel on Transverse Bed Slopes in Rotating Annular Flume Experiments

Large‐scale morphology, in particular meander bend depth, bar dimensions, and bifurcation dynamics, are greatly affected by the deflection of sediment transport on transverse bed slopes due to gravity and by secondary flows. Overestimating the transverse bed slope effect in morphodynamic models leads to flattening of the morphology, while underestimating leads to unrealistically steep bars and banks and a higher braiding index downstream. However, existing transverse bed slope predictors are based on a small set of experiments with a minor range of flow conditions and sediment sizes, and in practice models are calibrated on measured morphology. The objective of this research is to experimentally quantify the transverse bed slope effect for a large range of near‐bed flow conditions with varying secondary flow intensity, sediment sizes (0.17–4 mm), sediment transport mode, and bed state to test existing predictors. We conducted over 200 experiments in a rotating annular flume with counterrotating floor, which allows control of the secondary flow intensity separate from the streamwise flow velocity. Flow velocity vectors were determined with a calibrated analytical model accounting for rough bed conditions. We isolated separate effects of all important parameters on the transverse slope. Resulting equilibrium transverse slopes show a clear trend with varying sediment mobilities and secondary flow intensities that deviate from known predictors depending on Shields number, and strongly depend on bed state and sediment transport mode. Fitted functions are provided for application in morphodynamic modelin

Persistently high incidence of HIV and poor service uptake in adolescent girls and young women in rural KwaZulu-Natal, South Africa prior to DREAMS.

BACKGROUND: Adolescent girls and young women (AGYW) bear the brunt of the HIV epidemic in South Africa. 'DREAMS' aims to reduce HIV incidence through multi-level combination prevention. We describe HIV incidence and uptake of HIV and sexual reproductive health (SRH) by AGYW in KwaZulu-Natal (KZN), prior to DREAMS. METHODS: Longitudinal and cross-sectional analysis of women (15-24 year old) in a population-based HIV incidence cohort within a demographic surveillance site in KZN. Observation time for HIV incidence was person-years at risk while resident. "Current use of contraceptives" and "having an HIV test in the past 12 months" was compared between 2011 and 2015. RESULTS: In 2015, HIV prevalence was 11.0% and 34.1% and HIV incidence (2011-2015) was 4.54% (95%CI:3.89-5.30) and 7.45% (95%CI:6.51-8.51) per year in 15-19 and 20-24 year olds respectively, with no significant decline compared to 2006-2010. In 2015, 90.7% of 20-24-year-olds were unemployed, 36.4% and 51.7% of 15-19 and 20-24 year olds reported recent migration; 20.9% and 72.6% of 15-19 and 20-24 year olds had ever been pregnant. In 2015, less than 50% reported condom-use at last sex, 15.0% of 15-19 year olds and 48.9% of 20-24 year olds were currently using contraception and 32.0% and 66.7% of 15-19 and 20-24 year olds had tested for HIV in the past 12 months. There had been no improvement compared to 2011. Factors associated with AGYW testing for HIV in the past 12 months were, survey year-2011 more likely than 2015 (aOR = 0.50), number of partners (aOR = 3.25), ever been pregnant (aOR = 2.47) and knowing where to find ART (aOR = 1.54). Factors associated with contraception use were being older (aOR = 4.83); ever been pregnant (aOR = 12.62); knowing where to get ART (aOR = 1.79) and having had an HIV test in past 12 months (aOR = 1.74). CONCLUSION: Prior to DREAMS, HIV incidence in AGYW was high. HIV and SRH service uptake did not improve and was suboptimal. Findings highlight the need for combination HIV prevention programmes for AGYW in this economically vulnerable area