The demand for residential electricity in South Africa

This paper examines the residential demand for electricity in South Africa as a function of real gross domestic product per capita, and the price of electricity during the period 1978–2005. We make use of the bounds testing approach to cointegration within an autoregressive distributed framework, suggested by Pesaran et al. [2001. Bounds testing approaches to the analysis of level relationships. Journal of Applied Econometrics 16(3) 289–326]. Following the literature, we use a linear double-logarithmic form using income and price as independent variables in the empirical analysis. In the long run, we find that income is the main determinant of electricity demand, while electricity price is insignificant.     

Remote sensing of phytoplankton functional types

The principal goal in early missions of satellite-borne visible spectral radiometry (ocean colour) was to create synoptic fields of phytoplankton biomass indexed as concentration of chlorophyll-a. In the context of climate change, a major application of the results has been in the modelling of primary production and the ocean carbon cycle. It is now recognised that a partition of the marine autotrophic pool into a suite of phytoplankton functional types, each type having a characteristic role in the biogeochemical cycle of the ocean, would increase our understanding of the role of phytoplankton in the global carbon cycle. At the same time, new methods have been emerging that use visible spectral radiometry to map some of the phytoplankton functional types. Here, we assess the state of the art, and suggest paths for future work.     

Towards Systematic Achievement of Compliance in Service-Oriented Architectures: The MASTER Approach

Service-oriented architectures (SOA) have been successfully adapted by agile businesses to support dynamic outsourcing of business processes and the maintenance of business ecosystems. Still, businesses need to comply with applicable laws and regulations. Abstract service interfaces, distributed ownership and cross-domain operations introduce new challenges for the implementation of compliance controls and the assessment of their effectiveness. In this paper, we analyze the challenges for automated support of the enforcement and evaluation of IT security controls in a SOA. We introduce these challenges by means of an example control, and outline a methodology and a high-level architecture that supports the phases of the control lifecycle through dedicated components for observation, evaluation, decision support and reaction. The approach is model-based and features policy-driven controls. A monitoring infrastructure assesses observations in terms of key indicators and interprets them in business terms. Reaction is supported through components that implement both automated enforcement and the provision of feedback by a human user. The resulting architecture essentially is a decoupled security architecture for SOA with enhanced analysis capabilities and will be detailed and implemented in the MASTER project.     

Prediction of Hansen Solubility Parameters with a New Group-Contribution Method

A group-contribution method for the estimation of Hansen solubility parameters of pure organic compounds is presented. It uses two kinds of characteristic groups: first-order groups that describe the basic molecular structure of compounds and second-order groups, which are based on the conjugation theory and improve the accuracy of predictions. A large variety of characteristic groups ensure the prediction of Hansen solubility parameters for a broad series of organic compounds, including those having complex multi-ring, heterocyclic, and aromatic structures. The predictions are exclusively based on the molecular structure of compounds, and no experimental data are needed. The predicted values permit a fairly reliable selection of solvents based on the radius of a Hansen solubility parameter sphere or on a Teas parameter ternary plot. Especially designed algorithms permit the preparation of a list of new molecular structures which, if synthesized, could be the ideally suited solvents for a series of corresponding applications.     

Modeling nitrate fluxes at the catchment scale using the integrated tool CAWAQS

Nitrates fluxes in the Grand Morin basin (1200 km(2)), that is subjected to intense agricultural pressure, are considered using in-stream observations (around 250 sampling days over 5 years) and physically based simulations using the CAWAQS model (CAtchment WAter Quality Simulator). In-stream nitrate concentration averaged 6 mg N L(-1), increasing by approximately 0.2 mg N L(-1) yr(-1) around this value (period 1991-1996). Our results show that, over the period of 1991-1996, the differences between in-stream observed nitrate concentrations and simulated nitrate concentrations result from nitrate losses at the basin scale. These losses are due to denitrification by transfer through wetlands, alluvial plains, the hyporheic zone, and by benthic processes in rivers. A mean annual mass balance at the basin scale indicates that 40% of the infiltration flux (3360 kg N km(-2) yr(-1)) is removed from the system via the river network, 40% is stored in aquifers and 20% is lost by denitrification (period 1991-1996).     

Build as you earn and learn: informal urbanism and incremental housing financing in Kumasi,Ghana

The continuous evolution, proliferation and resilience of informal housing in cities of developing countries defy all attempts by their formal planning processes to marginalise and relegate them to the periphery. In most instances, their rapid and uncontrolled growth has overwhelmed city planning authorities. More importantly, strategies for financing these informal housing units present complex networks of sources not clearly discussed in the housing literature. Using two informal communities—Ayigya-Zongo and Dakodwom—in Kumasi, Ghana, this paper explores the nature and characteristics of these non-conventional housing financing strategies. The study reveals an evolving and enduring non-conventional informal housing financing system effective for providing convenient and affordable housing for the urban poor; but this system is continuously sidelined by the conventional urban planning and housing financing systems. We argue against these attitudes of formal institutions towards these non-conventional housing financing strategies, and submit that these strategies are the gradual, incremental, and collective responses of residents in informal communities to a hostile formal urban planning and housing environment. Hence the dynamics of these non-conventional housing financing schemes point to a complex and fluid network of informal housing financial sources and structures, which are co-evolving with the processes of informal urbanisation and social learning among residents in informal settlements.     

Microbiological quality of tomatoes and peppers produced under the good agricultural practices protocol AGRO 2-1 & 2-2 in Crete, Greece

The efficiency of the good agricultural practices (GAP) protocol AGRO 2-1 & 2-2, in advancing microbiological-quality of tomatoes and peppers, was studied in greenhouses at Ierapetra, Crete, Greece. The 240 tested vegetables-samples, produced under AGRO 2-1 & 2-2, showed satisfactory quality: Listeria monocytogenes absent per 25 g; Escherichia coli < 20 Colony Forming Units per gram (CFU/g); total coliforms 4.37–4.68 log CFU/g; aerobic plate counts 5.78–5.92 log CFU/g. Based on actual results and practices evaluation, we conclude that AGRO 2-1 & 2-2 can reduce microbial hazards for consumers and furthermore can establish practices in compliance to basic Euro-Retailer-Produce GAP (EUREPGAP) requirements.     

Silica based polishing of {100} and {111} single crystal diamond

Diamond is one of the hardest and most difficult to polish materials. In this paper, the polishing of {111} and {100} single crystal diamond surfaces by standard chemical mechanical polishing, as used in the silicon industry, is demonstrated. A Logitech Tribo Chemical Mechanical Polishing system with Logitech SF1 Syton and a polyurethane/polyester polishing pad was used. A reduction in roughness from 0.92 to 0.23 nm root mean square and 0.31 to 0.09 nm rms for {100} and {111} samples respectively was observed.     

RAB10 Interacts with ABCB4 and Regulates Its Intracellular Traffic

ABCB4 (ATP-binding cassette subfamily B member 4) is an ABC transporter expressed at the canalicular membrane of hepatocytes where it ensures phosphatidylcholine secretion into bile. Genetic variations of ABCB4 are associated with several rare cholestatic diseases. The available treatments are not efficient for a significant proportion of patients with ABCB4-related diseases and liver transplantation is often required. The development of novel therapies requires a deep understanding of the molecular mechanisms regulating ABCB4 expression, intracellular traffic, and function. Using an immunoprecipitation approach combined with mass spectrometry analyses, we have identified the small GTPase RAB10 as a novel molecular partner of ABCB4. Our results indicate that the overexpression of wild type RAB10 or its dominant-active mutant significantly increases the amount of ABCB4 at the plasma membrane expression and its phosphatidylcholine floppase function. Contrariwise, RAB10 silencing induces the intracellular retention of ABCB4 and then indirectly diminishes its secretory function. Taken together, our findings suggest that RAB10 regulates the plasma membrane targeting of ABCB4 and consequently its capacity to mediate phosphatidylcholine secretion.