Suicides on Commuter Rail in California: Possible Patterns — A Case Study, Research Report 10-05

Suicides on rail systems constitute a significant social concern. Reports in local media, whether in newspapers, television, or radio, have brought awareness to this very sensitive and personal subject. This is also true for the San Francisco Bay Area. These events also cause severe trauma for the train operators and staff of the system as well as disruption and cost to society. The overall objective of this project was to conduct a pilot study to identify possible patterns in suicides associated with urban commuter rail systems in California. The Caltrain commuter rail system in the San Francisco Bay Area was used as the subject system for the pilot study. The primary intent of the data analysis was to determine whether suicides along the Caltrain tracks exhibited patterns. Pattern detection in this study was conducted primarily on the basis of time and location. Because the data were readily available, the gender factor was also included in the analysis, although this is not a factor that is connected to the rail system. It was concluded that the data did show some patterns for suicides with respect to time and location. Some of the patterns can be explained while the reasons for some are not immediately obvious. However, the patterns in the latter category did not indicate a particularly attractive location or possible source for suicides

Epidemiological research methods. Part VII. Epidemiological research in health planning

CITATION: Yach, D. & Botha, J. L. 1987. Epidemiological research methods. Part VII. Epidemiological research in health planning. South African Medical Journal, 72:633-636.The original publication is available at http://www.samj.org.zaThe goal of epidemiology is to improve the health status of human populations. In our series thus far we have srressed the need to use the correct design for epidemiological studies, a sampling scheme that yields interpretable results, measurements that are both valid and reliable, and finally the appropriate analysis. These methodological considerations are of importance if the goal is to be reached. In this article we assume that most of these issues have been adequately dealt with and focus on how the results of epidemiological research can be used by health planners to improve the health status of regions and the country as a whole.Publisher’s versio

Epidemiological research methods. Part II. Descriptive studies

CITATION: Botha, J. L. & Yach, D. 1986. Epidemiological research methods. Part II. Descriptive studies. South African Medical Journal, 70:766-772.The original publication is available at http://www.samj.org.zaIn a descriptive study, therefore, the magnitude and distribution of a health problem in a specified population is studied in terms of TIME (when did it occur?), PLACE (where did it occur?) and PERSON (which groups are affected?). The design starts with an idea that occurs to the researcher about a particular problem. This is followed by selecting a group of individuals to be studied (sampling), considering which attributes to measure (measurement), describing the findings, and finally drawing conclusions on the basis of the findings. Commonly, new ideas or hypotheses are generated in this final stage, usually regarding possible explanations for the health problems described (cause-effect relationships). Such relationships may be attempts to explain the aetiology of diseases or the effect of preventive, curative or rehabilitative measures. Important issues affecting the reliability of the sampling and measurement processes are discussed, some descriptive statistical measures demonstrated and how conclusions are affected by these, are indicated.Publisher’s versio

Die bepaling van die ‘sentrum van hoofbelange’ by oorgrens insolvensies: Is die Parmalat-benadering voldoende om die behoeftes van moderne handel te bevredig?

Despite various viewpoints on the determination of the centre of main interest (COMI), the legal question in this investigation is whether, and to what extent, the approach in In re Eurofood IFSC Ltd (the Parmalat case) brings about an effective solution for the determination of the location of the COMI of individual companies, either unattached or as part of a group (in contrast with companies forming a so called economic unit). There exists a presumption that the COMI is situated there where the company’s registered office is. This is the physical factor in determining the COMI. There is also a mental or psychological factor. The COMI must correspond with the place which third parties (including foreigners) regard as the place where the debtor ordinarily manages its business and most prominent interests on a regular basis. If the registered office is situated at one place and the judgment of third parties with regard to the COMI is elsewhere, the presumption will not come into operation and the ordinary onus of proof will rest on the party concerned. If the subsidiary’s registered office and the opinion of third parties point to the same location (in order for the presumption to come into operation) the holding company should lead more substantial evidence so as to rebut the presumption. The presumption shall not be rebutted easily. An essential and delicate process of weighing up relevant factors should take place. The COMI must be identified with reference to criteria which are objectively foreseeable by all parties involved

Resistance or tolerance: an examination of aphid (Sitobion yakini) phloem feeding on Betta and Betta-Dn wheat (Triticum aestivum)

Engineering pest resistance into crops is important. However, the mechanisms of resistance are not clearly understood. In this study, we examined the effects of aphid feeding on Russian wheat aphid-resistant and -susceptible cultivars of wheat (Triticum aestivum L.); Betta-Dn and Betta, respectively, by the grass aphid, Sitobion yakini (Eastop). These cultivars were grown with or without aphid colonies. In each case, we examined the plants specifically for the formation of wound callose associated with the phloem, using aniline blue and fluorescence microscopy. We observed that aphid feeding stimulated the formation of wound callose in the susceptible cultivar, but that callose was comparatively reduced in the resistant cultivar of wheat. In a separate series of experiments, the xenobiotic, 5, 6-carboxyfluorescein diacetate was applied to attached sink leaves, distal to feeding aphids. When leaf segments were examined four hours after application, little evidence of phloem transport of the fluorescent cleavage product, 5, 6-carboxyfluorescein (5, 6-CF), was evident below known aphid-probed sieve tubes. Low levels or absence of 5, 6-CF indicates that either the aphids have successfully redirected sap to themselves, or that the phloem is no longer functional. In contrast, 5, 6-CF transport was evident below sites of aphid probing in Betta-Dn, suggesting that the phloem was still capable of long-distance transport. In addition, callose deposition was reduced in Betta-Dn leaf phloem and it is surmised that transport was not as affected by aphid feeding in the resistant cultivar. This indicates that the ‘resistant’ wheat cultivar may in fact be tolerant to aphid feeding by successfully overcoming the nutrient drain that feeding aphids imposed on the phloem transport system

The intake and quality of breakfast consumption in adolescents attending public secondary schools in the North West province, South Africa

Objectives: The objectives of the study were to determine the proportion and quality of breakfast intake in adolescents, and to determine the effect of breakfast intake and quality on overall diet quality.Design: A cross-sectional quantitative study design was used.Setting: The setting was seven public secondary schools in Potchefstroom and the surrounding areas in North West province.Subjects: The subjects were randomly selected adolescents in grades 9-11 (n = 244).Outcome measures: A self-administered demographic questionnaire was completed by the adolescents. Single 24-hour recall, using the four-stage multiple-pass method, was conducted to obtain information on breakfast and dietary intake for the day. Breakfast quality was measured by applying a breakfast quality score. The Diet Quality Index Revised was used to assess the quality of the overall diet. Spearman’s rank correlation coefficient was employed to assess an association between the continuous variables. The chi-square or Fisher’s exact test was utilised to assess an association between the categorical variables.Results: The proportion of breakfast intake and skipping was 81% and 19%, respectively. The mean breakfast quality score was moderate (3.1). No significant difference was shown in the diet quality score for the breakfast eaters and skippers. The breakfast quality score was marginally associated with calcium intake (p-value < 0.0001, r = 0.418), phosphorous intake (p-value < 0.0001, r = 0.378) and total diversity score (p-value < 0.0001, r = 0.369).Conclusion: The proportion of breakfast skipping, moderate quality of the breakfast consumed and trend of improved nutrient intake with improved breakfast quality highlights the need for breakfast education and intervention as part of the Integrated School Health Policy.Keywords: adolescent, breakfast, breakfast quality, diet quality, adolescenc

The isolation and characterisation of Xylophilus ampelinus

Bacterial blight, caused by Xylophilus ampelinus (PANAGOPOULUS) WILLEMS et al. is a destructive disease of grapevine (Vitis vinifera). Incubation of cuttings at 15 °C for three days under moist conditions significantly increased the number of isolated X. ampelinus colonies. This treatment facilitates the isolation of the pathogen from infected material from which it could previously not be isolated

Strong plasmonic fluorescence enhancement of individual plant light-harvesting complexes

Plasmonic coupling of metallic nanoparticles and adjacent pigments can dramatically increase the brightness of the pigments due to the enhanced local electric field. Here, we demonstrate that the fluorescence brightness of a single plant light-harvesting complex (LHCII) can be significantly enhanced when coupled to single gold nanorods (AuNRs). The AuNRs utilized in this study were prepared via chemical reactions, and the hybrid system was constructed using a simple and economical spin-assisted layer-by-layer technique. Enhancement of fluorescence brightness of up to 240-fold was observed, accompanied by a 109-fold decrease in the average (amplitude-weighted) fluorescence lifetime from approximately 3.5 ns down to 32 ps, corresponding to an excitation enhancement of 63-fold and emission enhancement of up to 3.8-fold. This large enhancement is due to the strong spectral overlap of the longitudinal localized surface plasmon resonance of the utilized AuNRs and the absorption or emission bands of LHCII. This study provides an inexpensive strategy to explore the fluorescence dynamics of weakly emitting photosynthetic light-harvesting complexes at the single molecule level.Comment: 23 pages, 6 figures, 2 supplementary figures, and supplementary equation

Characterisation of penA and tetM resistance genes of Neisseria gonorrhoeae isolated in southern Africa - epidemiological monitoring and resistance development

Objective. To investigate penA and tetM resistance gene variation of Neisseria gonorrhoeae in order to define gene types for epidemiological monitoring and resistance development. Design. Isolates of N. gonorrhoeae which were susceptible and resistant to penicillin and/or tetracycline were selected. Strains comprised South African isolates (22 from Bloemfontein, 13 from Transvaal, 20 from the Cape) and 15 Botswana and 4 Namibia isolates. The penA genes (2 kb) of all strains and tetM genes (765 bp) of 11 high-level tetracycline-resistant strains were amplified and restricted with Hpall. Results and conclusions. Twelve different Hpall fingerprint patterns were obtained from the 74 isolates analysed for penicillin-binding protein (PBP) 2 gene (penA) alterations. Focusing on the transpeptidase domain, 25 isolates (3 whole gene patterns, minimal inhibitory concentrations (MICs) ~ 0,03 - 0,125 ug/ml) had restriction sites equivalent to those previously described for a susceptible strain. Of the remaining 9 PBP 2 'gene groups, 25 strains fell into a designated group E. Penicillin/ penicillin + clavulanic acid MICs determined on these group E isolates gave a range of 0,125 - 2,0 ug/ml, although MICs against 4 strains were ~ 0,03 ug/ml. MICs of penicillin/penicillin + c1avulanic acid for the 24 isolates that contained altered PBP 2 transpeptidase gene regions not designated group E were only ~ 0,03 - 0,125 ug/ml. The lack of a Hpall restriction site at nucleotide 1934 in the PBP 2 gene of group E strains was indicative of a small terminal region of N. cinerea DNA. This gene block, which was found in all the southern African areas studied, appears to predispose isolates to increased penicillin resistance. The 25,2 MDa conjugative plasmid carrying the tetM resistance determinant was readily demonstrated in 11 Botswana Namibia isolates exhibiting high-level resistance to tetracycline (MICs > 16 ug/ml). The tetM gene was shown to be of the American type

Enterococcal endocarditis - a case treated with teicoplanin and amoxycillin

The study aimed to determine the antibacterial therapy effective in the cure of endocarditis caused by Enterococcus faecalis resistant to clinically achievable levels of vancomycin. Isolation of the causative enterococcus had been achieved by direct inoculation of the resected valve into the culture medium in theatre. The patient was known to have had an aortic valve defect since childhood and had recently undergone splenectomy following trauma. Blood cultures were negative prior to valve replacement. A perivalvular abscess was noted at operation. In vitro minimal bactericidal results and serum activity were the basis of the postoperative choice of drugs. The minimal bactericidal level of teicoplanin was 250 µg/ml and that of amoxycillin 64 µg/ml. Neither is achievable with the advocated dosage. A combination of these two cell-wall-active agents successfully eliminated the infection. Acting at two different sites in the synthesis of the bacterial cell wall, teicoplanin and amoxycillin were found to be bactericidal in vitro at the trough levels of the antibiotics in the serum. The patient recovered fully