A reconfigurable array processor

Thesis (PhD)--University of Stellenbosch, 1996.ENGLISH ABSTRACT: This dissertation reports on an investigation of the trade-off of the properties of presently available fixed and reconfigurable logic to find an optimal use for both types of logic in a typical engineering application. The research vehicle is a 32 bit floating point matrix-vector array processor. The system named MIX is designed, simulated, built and tested and the results are evaluated. Simulation and synthesis tools are used to extensively and a firm base for further research is established. State machines are implemented with a shift register technique developed earlier by the author. The results prove that fixed logic is most suited for subsystems such as memories and floating point units where reconfiguration is not necessarily required, but high logic density and speed are essential. Reconfigurable logic proves most useful for control functions and simple data manipulation. Delays resulting form the routing of data through the reconfigurable logic, as hidden by using pipeline techniques. It is proven that the performance of a mixed logic system approaches that of a pure fixed logic implementation, if the design allows the overlap of the execution of functions in the fixed and reconfigurable subsystems.AFRIKAANSE OPSOMMING: Hierdie verhandeling rapporteer oor 'n ondersoek van die afspeel van die eienskappe van huidig beskikbare vast en herkonfigureerbare logika om 'n optimale gebruik te vind vir beide tipe logika in 'n tipiese ingenieurs toepassing. Die voertuig vir die navorsing is 'n 32 bis wisselpunt matriks-vektor verwerker. Die MIX stelsel is ontwerp, gesimuleer, gebou en die resultate geevalueer. Simulasie en sintese gereedskap word vryelik gebruik en 'n ferm basis vir verder navorsing is geskep. Toestandmasjiene is met 'n skuifregistertegniek, wat vroeër deur die skrywer ontwikkel is, geïmplimenteer. Die resultate bewys dat vast logika mees geskik is vir substelsels, soos geheue en wisselpuntverwerkers, waar herkonfigurasie nie noodwendig benodig word nie maar hoe digtheid en spoed essensieël is. Herkonfiguureerbare logika is mees bruikbaar vir beheer en eenvoudige data manupilasie funksies. Die vertraging a.g.v. die roetering van data deur herkonfigureerbare logika, word versteek deur van pyplyn tegnieke gerbuik te maak. Dit word bewys dat die werkverrigting van 'n stelsel, met 'n mengsel van vaste en herkonfigureerbare logika, die van die stelsel met slegs vaste logika benader, indien die ontwerp toelaat dat uitvoering van funksies in die vaste en herkonfigureerbare substelsels in tyd oorvleuel.Doctora

The ABC-Type Multidrug Resistance Transporter LmrCD Is Responsible for an Extrusion-Based Mechanism of Bile Acid Resistance in Lactococcus lactis▿

Upon prolonged exposure to cholate and other toxic compounds, Lactococcus lactis develops a multidrug resistance phenotype that has been attributed to an elevated expression of the heterodimeric ABC-type multidrug transporter LmrCD. To investigate the molecular basis of bile acid resistance in L. lactis and to evaluate the contribution of efflux-based mechanisms in this process, the drug-sensitive L. lactis NZ9000 ΔlmrCD strain was challenged with cholate. A resistant strain was obtained that, compared to the parental strain, showed (i) significantly improved resistance toward several bile acids but not to drugs, (ii) morphological changes, and (iii) an altered susceptibility to antimicrobial peptides. Transcriptome and transport analyses suggest that the acquired resistance is unrelated to elevated transport activity but, instead, results from a multitude of stress responses, changes to the cell envelope, and metabolic changes. In contrast, wild-type cells induce the expression of lmrCD upon exposure to cholate, whereupon the cholate is actively extruded from the cells. Together, these data suggest a central role for an efflux-based mechanism in bile acid resistance and implicate LmrCD as the main system responsible in L. lactis

Cognitive agents for microscopic traffic simulations in virtual environments

Traffic simulations in current open world video games and driving simulators are still limited with respect to the complexity of the behavior of simulated agents. These limitations are typically due to scarce computational resources, but also to the applied methodologies. We suggest adding cognitive components to traffic agents in order to achieve more realistic behavior, such as opting for risky actions or occasionally breaking traffic rules. To achieve this goal, we start by adding a personality profile to each agent, which is based on the “Five Factor Model” from psychology. We test our enhancement on a specific traffic scenario where simplistic behaviors would lead to a complete standstill of traffic. Our results show that the approach resolves critical situations and keeps traffic flowing

Easy and rapid purification of highly active nisin

Nisin is an antimicrobial peptide produced and secreted by several L. lactis strains and is specifically active against Gram-positive bacteria. In previous studies, nisin was purified via cation exchange chromatography at low pH employing a single-step elution using 1 M NaCl. Here, we describe an optimized purification protocol using a five-step NaCl elution to remove contaminants. The obtained nisin is devoid of impurities and shows high bactericidal activity against the nisin-sensitive L. lactis strain NZ9000. Purified nisin exhibits an IC 50 of ∼3 nM, which is a tenfold improvement as compared to nisin obtained via the one-step elution procedure

Signature:.............................

I, the undersigned, hereby declare that the work contained in this thesis is my own original work and that I have not previously in its entirety or in part submitted it at any university for a degree

De toekomst van het wereldmilieu: modelmatige scenario-analyse ten behoeve van de eerste wereldmilieuverkenning door UNEP

This report documents the scenario analysis in UNEP's first Global Environment Outlook, published at the same time as the scenario analysis. This Outlook provides a pilot assessment of developments in the environment, both global and regional, between now and 2015, with a further projection to 2050. The study was carried out in support of the Agenda 21 interim evaluation, five years after 'Rio' and ten years after 'Brundtland'. The scenario analysis is based on only one scenario, Conventional Development. It features higher incomes and better health, but increasing regional inequalities. This pattern is reinforced by the analysis using detailed environmental models. Agricultural land use has to expand considerably in order to meet the growing demand for food, while agricultural productivity is not growing quickly enough in Africa and Asia. The little that remains of natural areas comes under heavy pressure. The ratio between water demand and availability becomes problematic in an increasing number of the world's catchment areas, although there are strong regional differences. Trade in food products becomes even more important than it is now, both for one's well-being and for the question on where the environmental pressures will occur. The necessary demographic and health transitions are illustrated with case studies for India, Mexico and the Netherlands. Protection of the environment will become an increasingly important factor in improving healthy life expectancy in developing countries. Future generations will be able to use energy, land and water more efficiently. Although the scenario analyzed in this study is rather optimistic in this respect. The assumed efficiency increases are by and large insufficient to meet the absolute growth in demand. On the other hand, there is technically speaking evidence given of considerable room for reducing the pressure on natural resources - assuming political determination, of course.Dit rapport bevat de details van de scenario-analyse in de gelijktijdig verschijnende eerste Global Environment Outlook, onder auspicien van UNEP. Dit is een proeve van een wereldmilieuverkenning tot 2015 met een doorkijkje naar 2050. De studie is uitgevoerd ten behoeve van de tussenbalans van Agenda 21, vijf jaar na 'Rio' en tien jaar na 'Brundtland'. De scenario-analyse is gebaseerd op slechts een scenario, het Conventional Development scenario. Impliciet daarin is dat hoewel de gemiddelde welvaart stijgt, de verschillen in de wereld alleen maar toenemen. De analyse met behulp van gedetailleerde milieumodellen versterkt dat beeld. Het landbouwareaal breidt sterk uit om aan de toenemende vraag naar voedsel te voldoen, bij achterblijvende landbouwproductiviteit in Afrika en Azie. Van de natuurgebieden blijft niet veel over, en wat overblijft komt onder grote druk. De verhouding tussen beschikbaar en benodigd zoet water wordt ongunstiger, met sterke regionale verschillen. Handel in voedsel wordt een steeds belangrijker factor, zowel voor welvaart als voor de vraag waar op de wereld het milieu het meest belast wordt. De noodzakelijke transities op het gebied van gezondheid en demografische ontwikkelingen worden geillustreerd met case-studies over India, Mexico en Nederland. Milieubeheer zal gaandeweg een belangrijker factor worden bij het bevorderen van een gezonde levensverwachting in ontwikkelingslanden. Toekomstige generaties zullen steeds effectiever omspringen met energie, land en water. Maar hoewel het onderzochte scenario op dit punt tamelijk optimistisch is, zijn de veronderstelde efficiencyverbeteringen over het geheel genomen onvoldoende om de groei van de behoefte op te vangen. Aan de andere kant laten voorlopige berekeningen zien dat er technisch gesproken veel ruimte is om de druk op natuurlijke hulpbronnen te verminderen - aangenomen dat de politieke wil aanwezig is

De toekomst van het wereldmilieu: modelmatige scenario-analyse ten behoeve van de eerste wereldmilieuverkenning door UNEP

Dit rapport bevat de details van de scenario-analyse in de gelijktijdig verschijnende eerste Global Environment Outlook, onder auspicien van UNEP. Dit is een proeve van een wereldmilieuverkenning tot 2015 met een doorkijkje naar 2050. De studie is uitgevoerd ten behoeve van de tussenbalans van Agenda 21, vijf jaar na 'Rio' en tien jaar na 'Brundtland'. De scenario-analyse is gebaseerd op slechts een scenario, het Conventional Development scenario. Impliciet daarin is dat hoewel de gemiddelde welvaart stijgt, de verschillen in de wereld alleen maar toenemen. De analyse met behulp van gedetailleerde milieumodellen versterkt dat beeld. Het landbouwareaal breidt sterk uit om aan de toenemende vraag naar voedsel te voldoen, bij achterblijvende landbouwproductiviteit in Afrika en Azie. Van de natuurgebieden blijft niet veel over, en wat overblijft komt onder grote druk. De verhouding tussen beschikbaar en benodigd zoet water wordt ongunstiger, met sterke regionale verschillen. Handel in voedsel wordt een steeds belangrijker factor, zowel voor welvaart als voor de vraag waar op de wereld het milieu het meest belast wordt. De noodzakelijke transities op het gebied van gezondheid en demografische ontwikkelingen worden geillustreerd met case-studies over India, Mexico en Nederland. Milieubeheer zal gaandeweg een belangrijker factor worden bij het bevorderen van een gezonde levensverwachting in ontwikkelingslanden. Toekomstige generaties zullen steeds effectiever omspringen met energie, land en water. Maar hoewel het onderzochte scenario op dit punt tamelijk optimistisch is, zijn de veronderstelde efficiencyverbeteringen over het geheel genomen onvoldoende om de groei van de behoefte op te vangen. Aan de andere kant laten voorlopige berekeningen zien dat er technisch gesproken veel ruimte is om de druk op natuurlijke hulpbronnen te verminderen - aangenomen dat de politieke wil aanwezig is.This report documents the scenario analysis in UNEP's first Global Environment Outlook, published at the same time as the scenario analysis. This Outlook provides a pilot assessment of developments in the environment, both global and regional, between now and 2015, with a further projection to 2050. The study was carried out in support of the Agenda 21 interim evaluation, five years after 'Rio' and ten years after 'Brundtland'. The scenario analysis is based on only one scenario, Conventional Development. It features higher incomes and better health, but increasing regional inequalities. This pattern is reinforced by the analysis using detailed environmental models. Agricultural land use has to expand considerably in order to meet the growing demand for food, while agricultural productivity is not growing quickly enough in Africa and Asia. The little that remains of natural areas comes under heavy pressure. The ratio between water demand and availability becomes problematic in an increasing number of the world's catchment areas, although there are strong regional differences. Trade in food products becomes even more important than it is now, both for one's well-being and for the question on where the environmental pressures will occur. The necessary demographic and health transitions are illustrated with case studies for India, Mexico and the Netherlands. Protection of the environment will become an increasingly important factor in improving healthy life expectancy in developing countries. Future generations will be able to use energy, land and water more efficiently. Although the scenario analyzed in this study is rather optimistic in this respect. The assumed efficiency increases are by and large insufficient to meet the absolute growth in demand. On the other hand, there is technically speaking evidence given of considerable room for reducing the pressure on natural resources - assuming political determination, of course.DGMUNE

Evolution of lacewings and allied orders using anchored phylogenomics (Neuroptera, Megaloptera, Raphidioptera)

Analysis of anchored hybrid enrichment (AHE) data under a variety of analytical parameters for a broadly representative sample of taxa (136 species representing all extant families) recovered a well-resolved and strongly supported tree for the higher phylogeny of Neuropterida that is highly concordant with previous estimates based on DNA sequence data. Important conclusions include: Megaloptera is sister to Neuroptera; Coniopterygidae is sister to all other lacewings; Osmylidae, Nevrorthidae and Sisyridae are recovered as a monophyletic Osmyloidea, and Rhachiberothidae and Berothidae were recovered within a paraphyletic Mantispidae. Contrary to previous studies, Chrysopidae and Hemerobiidae were not recovered as sister families and morphological similarities between larvae of both families supporting this assumption are reinterpreted as symplesiomorphies. Relationships among myrmeleontoid families are similar to recent studies except Ithonidae are placed as sister to Nymphidae. Notably, Ascalaphidae render Myrmeleontidae paraphyletic, again calling into question the status of Ascalaphidae as a separate family. Using statistical binning of partitioned loci based on a branch-length proxy, we found that the diversity of phylogenetic signal across partitions was minimal from the slowest to the fastest evolving loci and varied little over time. Ancestral character-state reconstruction of the sclerotization of the gular region in the larval head found that although it is present in Coleoptera, Raphidioptera and Megaloptera, it is lost early in lacewing evolution and then regained twice as a nonhomologous gula-like sclerite in distantly related clades. Reconstruction of the ancestral larval habitat also indicates that the ancestral neuropteridan larva was aquatic, regardless of the assumed condition (i.e., aquatic or terrestrial) of the outgroup (Coleopterida)