Catchment parameter analysis in fl ood hydrology using GIS applications

Published ArticleThe use of Geographical Information Systems (GIS) has permeated almost every field in the engineering, natural and social sciences, offering accurate, efficient, reproducible methods for collecting, viewing and analysing spatial data. GIS do not inherently have all the hydrological simulation capabilities that complex hydrological models do, but are used to determine many of the catchment parameters that hydrological models or design flood estimation methods require. The purpose of this study was to perform catchment parameter analysis using GIS applications available in the ArcGISTM environment. The paper will focus on the deployment of special GIS spatial modelling tools versus conventional manual methods used in conjunction with standard GIS tools to estimate typical catchment parameters, e.g. area, average catchment and watercourse slopes, main watercourse lengths and the catchment centroid. The manual catchment parameter estimation methods with GIS-based input parameters demonstrated an acceptable degree of association with the special GIS spatial modelling tools, but proved to be sensitive to biased user-input at different scale resolutions. GIS applications in an ArcGISTM environment for the purpose of catchment parameter analyses are recommended to be used as the standard procedure in any proposed hydrological assessment

Evaluation of the standard design flood method in selected basins in South Africa

Published ArticleDesign flood estimations display relatively wide confidence bands of uncertainty around all estimates of flood magnitude-frequency relationships. Taking cognisance of this, and the fact that most of the available design flood estimation methods in South Africa were developed in the 1970s and have not been updated since, led to the development of the Standard Design Flood (SDF) method (Alexander 2002a; 2002b; 2003). In this study, the SDF method was evaluated by establishing the accuracy of the regionalised SDF runoff coefficients, taking both the areal extent and homogeneous hydrological catchment responses into consideration. The SDF runoff coefficients were evaluated, calibrated and verified at a quaternary catchment level in SDF basin 9 (primary study area) and in 19 of the other 29 SDF basins in South Africa (secondary study areas) by establishing catchment parameters and evaluating the ratios between the results obtained through the SDF method and probabilistic analysis. The results showed that the original SDF method overestimated the magnitude and frequency (return period) of flood peaks in all the basins under consideration, while the verification results confirmed that the calibrated/verified SDF method, based on quaternary runoff coefficients, significantly improves the accuracy in comparison with the probabilistic analysis results. The result confirmed that the probabilisticbased approach of the original SDF method does not have the ability to overcome the deficiencies evident in the other design flood estimation techniques used in South Africa. Revision of the runoff coefficients at a quaternary catchment level is proposed

Water resources in Botswana with particular reference to the savanna regions

Production and development in the savanna regions of southern Africa are primarily determined by interactions between the limitations imposed by ecological determinants (such as rainfall and soil quality) and the management strategies of the specific region. Good planning, focussing on both the short and long-term effects of water use, is needed in water management strategies. Botswana is already experiencing so-called 'water stress' which is related to a number of factors such as rapidly increasing population leading to a sharp increase in water demand, low and variable rainfall, high rates of evaporation, and the high cost of exploiting existing water resources. At the current rates of abstraction, the lifetime of surface and groundwater resources is limited to decades. Botswana shares four river basins with its neighbouring countries. This results in a situation where 94% of the fresh water resources which Botswana can theoretically access originates outside its borders, making water resource management highly complex. Transnational sharing and management of water resources, therefore, plays a major role in securing sustainability of this precious resource

Effectiveness of e-recruiting : empirical evidence from the Rosebank business cluster in Auckland, New Zealand

This article focuses on the background of the \u27conventional\u27 or \u27old\u27 way of recruiting, it reviews different \u27new\u27 ways; e-recruiting and its effectiveness; advantages such as accessibility and disadvantages such as transgression of some legislation in e-recruiting and the impact it has on management. Face-to-face interviews were conducted with 102 companies within that population. A 36- question questionnaire was used and we employed random stratified cluster sampling. Research done in Auckland\u27s Rosebank Business Precinct (New Zealand) revealed that for certain job categories e-recruitment is effective. E-recruitment is revolutionising the way employers hire employees. Some implications for managers are pointed out such as the need to be trained for these changes; it can save a lot of money on advertisements; the savings could be used to develop careers or training for employees. The recommendations suggest that the HR objectives have to align with the organisational objectives to ensure that they recruit, select and employ the right candidate for the right job. A flow diagram for e-recruiting was developed by the authors for use by employers

Finite System Size Correction to the Effective Coupling in ϕ4\phi^4 Scattering

We compute and explore numerically the finite system size correction to NLO $2\to2$ scattering in massive scalar $\phi^4$ theory. The derivation uses "denominator regularization" (instead of the usual dimensional regularization) on a spacetime with spatial directions compactified to a torus, with characteristic lengths not necessarily of equal size. We determine a useful analytic continuation of the generalized Epstein zeta function to isolate the usual UV divergence. Self-consistently, the renormalized finite system size correction reduces to zero as the system size goes to infinity and, further, satisfies the optical theorem. One of our checks of unitarity leads to a generalization of a number theoretic result from Hardy and Ramanujan. Precise numerical exploration of the finite system size correction to the amplitude and coupling when two spatial dimensions are finite requires the exploitation of the analytic structure of the finite system size result via a dispersion relation. We find that the finite system size scattering amplitude exhibits "geometric" bound states. Even away from these bound states, the finite system size correction to the effective coupling can be large.Comment: 34 pages, 24 figure

NLO finite system size corrections to 2→22\to2 scattering in ϕ4\phi^4 theory using newly derived sum of sinc functions

Previously an equation of state for the relativistic hydrodynamics encountered in heavy-ion collisions at the LHC and RHIC has been calculated using lattice gauge theory methods. This leads to a prediction of very low viscosity, due to the calculated trace anomaly. Finite system corrections to this trace anomaly could challenge this calculation, since the lattice calculation was done in an effectively infinite system. In order to verify this trace anomaly it is sensible to add phenomenologically relevant finite system corrections. We investigate massive $\phi^4$ theory with periodic boundary conditions on $n$ of the 3 spatial dimensions. $2\to2$ NLO scattering is then computed. Using a newly derived formula for an arbitrary dimensional sum of sinc functions, we show that the NLO finite size corrections preserve unitarity.Comment: Submission to SciPos

Factors affecting the reproducibility of fermentation of grape juice and of the aroma composition of wines 1. Grape maturity, sugar, inoculum concentration, aeration, juice turbidity and ergosterol

Gas chromatographic analysis was used for the investigation of some factors which determine the production of volatile wine components during fermentation. Especially the effect of "heterogenous" juice factors such as turbidity and air content were investigated in respect of fermentation rate and the production of fatty acids, fusel alcohols and esters. lt was shown that the fermentation lag of clear filtered and de-aerated grape juices could be prevented by small ergosterol additions before inoculation. A marked similarity was observed in the chromatograms of wines from fermentations of clear juices which were stimulated either by air or by ergosterol. Grape maturity proved to be a major factor affecting the production of volatile acids, alcohols and esters during fermentation. Fermentations of de-aerated and clear filtered juice with an addition of 0.5 g bentonite/l yielded wines with the best scores an sensory evaluation.Maßgebliche Faktoren für die Reproduzierbarkeit der Vergärung von Traubenmostund die Aromazusammensetzung von WeinI. Traubenreife, Zucker, Konzentration des lnokulums, Luft, Klarheit des Mostesund ErgosterinEinige Faktoren, welche die Bildung flüchtiger Weininhaltsstoffe bei der Gärung beeinflussen, wurden gaschromatographisch untersucht. Besonders die Wirkung „heterogener" Faktoren im Traubenmost, wie zum Beispiel Trübung und Luftgehalt, auf die Gärungsgeschwindigkeit und die Bildung von Fettsäuren, Fuselalkoholen und Estern wurde untersucht. Es wurde gezeigt, daß die Gärungsverzögerung bei klarfiltrierten und entlüfteten Traubensäften durch die Zufügung kleiner Mengen von Ergosterin vor der Inokulation verhindert werden kann. Wurde die Gärung von geklärtem Most durch Luft oder durch Ergosterin angeregt, so zeigten die Chromatogramme der Weine eine starke Ähnlichkeit. Die Traubenreife erwies sich als der wichtigste Faktor, der die Bildung von flüchtigen Säuren, Alkoholen und Estern bei der Gärung beeinflußt. Die Vergärung von entlüftetem und klarfiltriertem Most mit Zusatz von 0,5 g Bentonit/l ergab Weine, die bei der Weinprobe die höchsten Punktezahlen erhielten

New trends regarding sustainability and integrated reporting for companies: what protection do directors have?

The authors explore some significant developments in recent times regarding modern expectations of corporations and the considerable impact of corporations on modern society. They also focus on some of the most dominant corporate law theories like the shareholder primacy theory, the enlightened shareholder value theory and the stakeholder theory. They illustrate that these developments require broader reporting than just financial reporting as is currently required by law for purposes of financial statements and reports. They then analyse the trend of broader reporting also on social and environmental issues. These forms of reporting have been done under general descriptive terms like corporate social reporting (CSR), sustainability reporting, integrated reporting and responsibility reporting. The question is then asked whether directors are opening themselves to greater liability by doing these forms of non-statutory reports. They compare three jurisdictions, namely Australia, Germany and South Africa. They conclude that the safe-harbour statutory provisions and some other statutory provisions in Australia and South Africa should be sufficient to protect directors against personal liability for judgment calls honestly made as long as the requirements of the statutory protection are present. The protection for directors in Germany seem to be more limited, especially in light of current statutory provisions requiring reporting on issues broader than financial issues and because of some recent developments in the European Union (EU) that will widen reporting obligations even further

Evaluation of the use of low-molecular-weight heparin for venous thromboembolism prophylaxis in medical patients

Background. Venous thromboembolism (VTE) complicates a significant proportion of medical admissions. As well as increasing patient morbidity, pulmonary embolism is one of the commonest preventable causes of in-hospital death. An increase in the use of pharmacological preventive measures has been advocated in recent years. South African (SA) and international guidelines have been published in an effort to promote the safe use of VTE prophylaxis.Objectives. To describe adherence to both local and international recommendations for VTE prophylaxis in an SA hospital with regard to appropriateness of the decision to prescribe or withhold low-molecular-weight heparin (LMWH), and to observe the practice of dose adjustment in special population groups.Methods. This was a prospective, observational study, and data were collected from consenting adults admitted to the medical wards. We assessed the patients’ VTE risk, bleeding risk and the presence of contraindications at the time of LMWH prescription as well as the dose prescribed, specifically taking into consideration adjustment for renal dysfunction and obesity.Results. Three hundred and fifty-two patients were enrolled, of whom 51.4% were male and 58.5% received LMWH. Primary outcomes. The appropriate overall decision according to both SA and international guidelines was made in 254 cases (72.2%). The inappropriate decision according to both guidelines was made in 79 cases (22.4%) and the appropriate decision according to one guideline only was made in 18 cases (5.1%), while 1 case (0.3%) was not categorised. Contraindications to VTE prophylaxis were present in 35 patients (9.9%), but 9 of these patients nevertheless received LMWH. An incorrect dose was prescribed in 36 cases (17.5%), the most common reason being an inappropriate reduction in the dose in mild renal dysfunction. Secondary outcomes. Other medications that may have increased bleeding risk were prescribed in 46 patients who received LMWH (22.3%). Mechanical prophylaxis was indicated in 25 (7.1%) of the total sample; however, none received this.Conclusions. Overall adherence to published guidelines for VTE prophylaxis has improved compared with other published reviews on the topic, but documentation of patients’ VTE risk in files is poor. Overuse in low-risk patients may be an unintended consequence of the widespread advocacy of LMWH use in hospital, highlighting the importance of adequate VTE risk stratification. Incorrect dosing in special population groups is an issue that needs to be addressed, as is non-utilisation of mechanical prophylaxis methods.

Composition analysis of nickel silicide formed from evaporated and sputtered nickel for microsystem devices

Nickel silicide (NiSi) is highly suitable for microsystem fabrication, exhibiting suitable mechanical properties and good resistance to bulk micromachining etchants. Conditions for the formation of nickel silicide by vacuum annealing thin films of nickel deposited on silicon substrates are investigated. Nickel silicide thin films formed using sputtered and evaporated nickel films were analysed using Auger electron spectroscopy, which has shown that evaporated thin films of nickel tend to form nickel silicide more readily and with less thermal effort