A case for incorporating standby generators into the South African electricity system

This paper examines how existing standby generators may benefit the South African electricity system. Eskom, the national electricity utility, supplies 92% of South Africa’s electricity needs at a price to consumers that is the lowest in the world, making it virtually impossible for alternative generation to compete. Installed electricity generation capacity is 38 154MW with a reserve margin of 8-10%. Eskom would prefer a margin closer to 15% but demand growth for the next year will reduce the margin further, to 3.75%. One response has been to introduce a demand management programme The country has begun to suffer more frequent outages, particularly during winter when demand is highest. One aspect of the management programme is to shift the two daily peaks to the ‘valleys’. Eskom estimates a possible 3 000MW capacity available from standby generators. The research should deliver a more accurate figure, as well as the location of these generators, particularly with respect to network constraints. Also considered are issues of synchronisation with the grid, emissions, noise and other environmental impacts associated with the operation of distributed generation, as well as the contractual conditions under which such an arrangement may be possible

Collected Observations Pertaining to Hog Cholera

This bulletin reports on the following: (1) the possible role of Salmonella suipestifer in failed vaccinations (vaccination breaks); (2) excessive serum dosages as a cause of vaccination breaks; (3) experiments with crystal-violet hog cholera vaccine and (4) hog cholera vaccine of tissue origin, and (5) phenolized hog cholera virus as a possible vehicle for pathogenic contaminants

A robustness study of parametric and non-parametric tests in model-based multifactor dimensionality reduction for epistasis detection

Background: Applying a statistical method implies identifying underlying (model) assumptions and checking their validity in the particular context. One of these contexts is association modeling for epistasis detection. Here, depending on the technique used, violation of model assumptions may result in increased type I error, power loss, or biased parameter estimates. Remedial measures for violated underlying conditions or assumptions include data transformation or selecting a more relaxed modeling or testing strategy. Model-Based Multifactor Dimensionality Reduction (MB-MDR) for epistasis detection relies on association testing between a trait and a factor consisting of multilocus genotype information. For quantitative traits, the framework is essentially Analysis of Variance (ANOVA) that decomposes the variability in the trait amongst the different factors. In this study, we assess through simulations, the cumulative effect of deviations from normality and homoscedasticity on the overall performance of quantitative Model-Based Multifactor Dimensionality Reduction (MB-MDR) to detect 2-locus epistasis signals in the absence of main effects. Methodology: Our simulation study focuses on pure epistasis models with varying degrees of genetic influence on a quantitative trait. Conditional on a multilocus genotype, we consider quantitative trait distributions that are normal, chi-square or Student's t with constant or non-constant phenotypic variances. All data are analyzed with MB-MDR using the built-in Student's t-test for association, as well as a novel MB-MDR implementation based on Welch's t-test. Traits are either left untransformed or are transformed into new traits via logarithmic, standardization or rank-based transformations, prior to MB-MDR modeling. Results: Our simulation results show that MB-MDR controls type I error and false positive rates irrespective of the association test considered. Empirically-based MB-MDR power estimates for MB-MDR with Welch's t-tests are generally lower than those for MB-MDR with Student's t-tests. Trait transformations involving ranks tend to lead to increased power compared to the other considered data transformations. Conclusions: When performing MB-MDR screening for gene-gene interactions with quantitative traits, we recommend to first rank-transform traits to normality and then to apply MB-MDR modeling with Student's t-tests as internal tests for association

The Effects of Penicillin on E. Rhusiopathiae Infected Pigeons

Advantage was taken of an opportunity to study the effects of penicillin on Erysipelothrix rhusiopathiae, the causative organism of swine erysipelas. Owing to the fact that swine cannot readily be infected with erysipelas by artificial methods, pigeons which are highly susceptible to the disease, were selected to serve as experimental animals. It was the purpose of these studies to ascertain whether or not the swine erysipelas bacillus is sensitive to the drug and incidentally to determine the possibility of finding application of penicillin in the treatment of swine

Studies on the Validity of Swine Erysipelas Culture-Vaccines

In countries where vaccination against swine erysipelas has been practiced during the last half century, there is a consensus among veterinarians that the best results are obtained when the live culture-vaccine is not only fresh and highly virulent but is endowed also with a good capacity for growth on artificial culture media. Apparently avirulent culture-vaccines are apt to engender only a transitory immunity or fail altogether. The problem presented by undesirable culture-vaccines was deemed to be of such importance to the swine industry that this Station undertook a series of experiments, to determine what influences might be accountable for the production of inferior vaccination materials

Transforming growth factor-β1 regulates chemokine and complement production by human proximal tubular epithelial cells

Transforming growth factor-γ1 regulates chemokine and complement production by human proximal tubular epithelial cells. Previously it has been demonstrated that human proximal tubular epithelial cells (PTEC) are able to produce chemokines (such as IL-8 and MCP-1) and complement components (such as C2, C3, C4 and factor H), and that production of these proteins is regulated by pro-inflammatory cytokines such as interleukin-1α (IL-1α), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ). Since TGF-γ is also expressed in the renal interstitium during inflammation, we investigated the effect of TGF-γ on the production of chemokines and complement components by PTEC in culture. Transforming growth factor-γ1 up-regulated IL-8 production by an average of 4.11 ± 1.0-fold. macrophage chemoattractant phagocyte (MCP-1) production, on the other hand, was down-regulated by TGF-γ1 by an average of 2.2 ± 0.7-fold. The production of C3 and C4 was also down-regulated after incubation with TGF-γ1 (1.9 ± 0.3- and 3.0 ± 1.2-fold, respectively). All effects were dose- and time-dependent and were found to be specific for TGF-γ1, as assessed by inhibition of the effect with a neutralizing antibody against TGF-γ1. These data, together with the knowledge that TGF-γ, chemokines and complement components play a role in several types of renal disease, suggest that TGF-γ is involved in the regulation of local expression of chemokines and complement components by tubular cells

The relation between sleep quality, sleep quantity, and gastrointestinal problems among colorectal cancer survivors:Result from the PROFILES registry

PURPOSE: Common residual symptoms among survivors of colorectal cancer (CRC) are sleep difficulties and gastrointestinal symptoms. Among patients with various gastrointestinal (inflammatory) diseases, sleep quality has been related to gastrointestinal symptoms. For CRC survivors, this relation is unclear; therefore, we examined the association between sleep quality and quantity with gastrointestinal symptoms among CRC survivors. METHODS: CRC survivors registered in the Netherlands Cancer Registry—Southern Region diagnosed between 2000 and 2009 received a survey on sleep quality and quantity (Pittsburgh Sleep Quality Index) and gastrointestinal symptoms (European Organisation for Research and Treatment of Cancer, Quality of Life Questionnaire-Colorectal 38, EORTC QLQ-CR38) in 2014 (≥ 4 years after diagnosis). Secondary cross-sectional data analyses related sleep quality and quantity separately with gastrointestinal symptoms by means of logistic regression analyses. RESULTS: In total, 1233 CRC survivors were included, of which 15% reported poor sleep quality. The least often reported gastrointestinal symptom was pain in the buttocks (15.1%) and most often reported was bloating (29.2%). CRC survivors with poor sleep quality were more likely to report gastrointestinal symptoms (p’s < 0.01). Survivors who slept < 6 h were more likely to report symptoms of bloating or flatulence, whereas survivors who slept 6–7 h reported more problems with indigestion. CONCLUSIONS: Worse sleep quality and short sleep duration were associated with higher occurrence of gastrointestinal symptoms. IMPLICATIONS FOR CANCER SURVIVORS: Understanding the interplay between sleep quality and gastrointestinal symptoms and underlying mechanisms adds to better aftercare and perhaps reduction of residual gastrointestinal symptoms in CRC survivors by improving sleep quality

On Store Design and Affective Consumer Experience - Effects of color and store layout as a function of shopping goals

Although a considerable body of literature is available documenting effects of store design, understanding of how and when store design affects consumer responses is limited. In this paper, it is argued that effects of two important design variables (i.e., color and layout) vary with consumers’ shopping goals. After presenting a literature review highlighting the importance of arousal and spatial control in explaining effects of store design, an experimental study is reported in which color and store layout were manipulated in a clothing store. Findings indicate that whereas recreational shoppers are primarily affected by store color, and report positive affect in a high-arousing environment, task-oriented shoppers are mainly affected by store layout and benefit from spacious layout conditions. In terns of practical implications, these findings suggest that an improvement of store atmospherics from recreational shoppers’ point of view does not frustrate task-oriented shoppers. Reversely, a more spacious store layout is likely to reduce irritation, nervousness and distress among task-oriented shoppers, without taking away the fun for recreational shoppers

Dimeric and polymeric IgA, but not monomeric IgA, enhance the production of IL-6 by human renal mesangial cells

Depositions of IgA in the renal glomerular mesangial area are a hallmark of IgA nephropathy, and are thought to be crucial for the onset of inflammation processes in IgA nephropathy. In this report we show that human mesangial cells (MC) in vitro bind IgA and that binding of IgA enhances the production of IL-6 by MC. Furthermore we show that the size of IgA is crucial in its capability to enhance IL-6 production. Monomeric IgA does not affect basic IL-6 production, whereas dimeric and polymeric IgA enhance IL-6 production up to 3- to 9-fold respectively. Additional studies demonstrate that enhanced IL-6 production by MC is not accompanied by increased proliferation of human mesangial cells, a finding which is distinct from that found with rat mesangial cells. Taken together, these fmdings suggest that deposition of dimeric and polymeric IgA in the mesangial area of human kidneys in IgA nephropathy may amplify local inflammation