A new fossil ichneumon wasp from the Lowermost Eocene amber of Paris Basin (France), with a checklist of fossil Ichneumonoidea s.l. (Insecta : Hymenoptera : Ichneumonidae : Metopiinae)

We describe a new fossil genus and species Palaeometopius eocenicus of Ichneumonidae Metopiinae (Insecta: Hymenoptera), from the Lowermost Eocene amber of the Paris Basin. A list of the described fossil Ichneumonidae is proposed

The use of bioassays to assess the toxicity of sediment in an acid mine drainage impacted river in Gauteng (South Africa)

Abstract: Sediment contamination may occur from various anthropogenic activities, such as mining-, agricultural- and industrial practices. Many of the contaminants arising from these activities enter the aquatic system and precipitate from the surrounding water, becoming bound to sediment particles. These bound contaminants may reach concentrations higher than in the overlying water. Although water quality may be acceptable, an aquatic system may still be at risk if the contaminated sediment were to be disturbed through flooding, bioturbation or changes in the water chemistry. These contaminants may then desorb into the water column and prove detrimental to life forms in contact and dependent on that water source. Sediment quality monitoring has been a widespread international initiative and has led to the development of sediment toxicity assessment methods. This study focused on sediment bioassays, namely, Phytotoxkit, Ostracodtoxkit F and the Diptera bioassay, in assessing sediment quality of the Tweelopiespruit-Rietspruit-Bloubankspruit river system in Gauteng, South Africa. This river is known to have been impacted by acid mine drainage (AMD) since late August, 2002. Exposure of river sediment from 7 sampling sites to these bioassays provided an eco-toxicological estimation of the acute toxicity and chronic toxicity emanating from the contaminated sediments. Physico-chemical analyses revealed higher levels of sediment contamination closer to the mine. The bioassays displayed a similar trend with greater sensitivities to sediments closer to the mine and lower sensitivities to the less contaminated sites further downstream. AMD was therefore the main driver for sediment contamination. Whilst not all contaminants were bioavailable, statistical analysis showed that there were significant correlations between the elevated contaminant concentrations closer to the mine and bioassay responses

Retention of engineering students

Abstract: Retention of engineering students is an international concern. Most countries report a shortage of engineers. By increasing the number of retained engineering students it is potentially possible to increase the number of engineering graduates. The purpose of this article is to identify and analyse what retention research has been done in the past to avoid unnecessary duplication. Although duplication may bring valuable new information, progress in this field has been slow. Therefore, the focus is on facilitating progress rather than seeking more accurate results. The three main themes identified in literature are: the individual’s internal and external characteristics that affect retention, the models that describe retention, conceptual and predictive, and the interventions attempted to improve retention. Further research into methods for improving student retention is certainly justified since in spite of existing research most institutions still struggle to retain engineering students

Biology Extended 1A

Exam paper (Supplementary) for second semeste

A conceptual framework to analyse supply chain designs

Objectives: Supply chain design (SCD) is a concept that forms an integral part of supply chain management (SCM). Effective SCD enhances supply chain integration (SCI) which in turn contributes towards improved supply chain performance. Therefore, organisations' supply chain designs need to be analysed. This article proposes a conceptual framework to analyse organisations' supply chain designs. The objective of this article is to determine whether the proposed conceptual framework is a workable instrument with which organisations can analyse their supply chain designs. Problem investigated: Effective SCD is a complex and demanding undertaking and has become a major challenge for organisations. Moreover, the literature suggests that organisations allow their supply chains to evolve rather than consciously designing them. Although the importance of SCD is emphasised, very little attention is given to what it entails exactly. The problem statement of this article is thus: What are the elements of SCD and how can these elements be included in a conceptual framework to analyse organisations' supply chain designs? Methodology: The methodology used in this article comprised two phases. Firstly, a literature review was conducted to identify SCD elements. The elements were used to develop a conceptual framework with which organisations can analyse their supply chain designs. Secondly, the conceptual framework was tested in 13 organisations to determine whether it is a workable instrument to analyse supply chain designs. The respondents were selected by means of non-probability sampling. Purposive, judgmental and convenience sampling methods were used to select the sample. Findings and implications: As mentioned, the conceptual framework was tested empirically within 13 organisations. The findings show that the conceptual framework is in fact a workable instrument to analyse supply chain designs. Value of the research: The research will make a contribution in the field of supply chain management and more specifically in the field of supply chain design. As mentioned, very little attention is given to the specifics of SCD. This article provides a more structured approach to analysing supply chain designs. Conclusion: SCD forms an important part of SCM and may play a role in improving performance. The conceptual framework proposed in this article will assist organisations with the analysis of their supply chain designs, which in turn may highlight potential areas in their supply chains where there may be room for improving their SCD practices

Structural and magnetic properties of CoPt mixed clusters

In this present work, we report a structural and magnetic study of mixed Co58Pt42 clusters. MgO, Nb and Si matrix can be used to embed clusters, avoiding any magnetic interactions between particles. Transmission Electron Microscopy (TEM) observations show that Co58Pt42 supported isolated clusters are about 2nm in diameter and crystallized in the A1 fcc chemically disordered phase. Grazing Incidence Small Angle X-ray Scattering (GISAXS) and Grazing Incidence Wide Angle X-ray Scattering (GIWAXS) reveal that buried clusters conserve these properties, interaction with matrix atoms being limited to their first atomic layers. Considering that 60% of particle atoms are located at surface, this interactions leads to a drastic change in magnetic properties which were investigated with conventional magnetometry and X-Ray Magnetic Circular Dichro\"{i}sm (XMCD). Magnetization and blocking temperature are weaker for clusters embedded in Nb than in MgO, and totally vanish in silicon as silicides are formed. Magnetic volume of clusters embedded in MgO is close to the crystallized volume determined by GIWAXS experiments. Cluster can be seen as a pure ferromagnetic CoPt crystallized core surrounded by a cluster-matrix mixed shell. The outer shell plays a predominant role in magnetic properties, especially for clusters embedded in niobium which have a blocking temperature 3 times smaller than clusters embedded in MgO

The clinical and biochemical effects of riboflavin and nicotinamide supplementation upon Bantu school children using maize meal as carrier medium

A comprehensive clinical, biochemical and technological investigation was undertaken to establish the feasibility of ,enriching maize meal with riboflavin and nicotinamide. It was clear from the results that the addition of these vitamins to, maize satisfied all the prerequisites of a -scientifically sound enrichment scheme, as laid down by the NNRI. It was found that the addition of 1 mg of riboflavin and 10 mg of nicotinamide per 400 g maize ,meal was adequate to effectively reduce the incidence of .subclinical deficiency of these two vitamins among Bantu schoolchildren. Since the enrichment was found to be -effective, as well as technologically and economically jeasible, it is strongly recommended that a compulsory national maize enrichment scheme be introduced with the .least possible delay

Predicting freshwater habitat integrity using land-use surrogates

Freshwater biodiversity is globally threatened due to human disturbances, but freshwater ecosystems have been accorded lessprotection than their terrestrial and marine counterparts. Few criteria exist for assessing the habitat integrity of rivers and data used for such assessments are generally of limited geographical coverage. Here, we use a fine-scale dataset describing river integrity in north-western South Africa to explore the extent to which measures of freshwater habitat integrity can be predicted from remotely sensed data, which are readily available in many parts of the world. A spatial statistical model was built using broad land-cover variables to predict the habitat integrity (subdivided into riparian and instream integrity) of rivers.We also explored the importance of the spatial scale. Results showed that riparian and, to a lesser degree, instream habitat integrity of river systems could be predicted with reasonable accuracy. The total area under natural vegetation was the most significant predictor of riparian integrity, which is best predicted by land-use activities at catchment level, rather than more locally. Our GIS-based model thus provides a fine-scale approach to assessing river habitat integrity as a supplement to landscape-level conservation plans for river systems, and represents a significant contribution towards the monitoring componentof the River Health Programme (RHP), which reports on the state of rivers in South Africa