Die akademie in Suid-Afrika: ’n vervullende professie?

Academe in South Africa: a fulfilling profession? South African academics possess a collective value system. However, other value systems impact not only on their value system but also on their academic work. They typically find themselves working in an institutional, a national and an international context, each with its own hierarchy of values. A theoretical discussion of (the role of) values in the academic workplace is followed by an overview of the professional values held by South African academics as measured by means of the Changing Academic Profession (CAP) Survey, which was carried out in 2008. The survey revealed, for instance, a rift between the institutional value hierarchy and that of the academic profession. It can therefore be concluded that many South African academics seem to lead relatively unfulfilled professional lives, among others, because they find themselves working in an environment (various contexts) with many contradictions. These problems should be addressed for the sake of the well-being of both the academic profession and of the higher education sector

Symmetry and the thermodynamics of currents in open quantum systems

Symmetry is a powerful concept in physics, and its recent application to understand nonequilibrium behavior is providing deep insights and groundbreaking exact results. Here we show how to harness symmetry to control transport and statistics in open quantum systems. Such control is enabled by a first-order-type dynamic phase transition in current statistics and the associated coexistence of different transport channels (or nonequilibrium steady states) classified by symmetry. Microreversibility then ensues, via the Gallavotti-Cohen fluctuation theorem, a twin dynamic phase transition for rare current fluctuations. Interestingly, the symmetry present in the initial state is spontaneously broken at the fluctuating level, where the quantum system selects the symmetry sector that maximally facilitates a given fluctuation. We illustrate these results in a qubit network model motivated by the problem of coherent energy harvesting in photosynthetic complexes, and introduce the concept of a symmetry-controlled quantum thermal switch, suggesting symmetry-based design strategies for quantum devices with controllable transport properties.Comment: 12 pages, 6 figure

Preparation and Scintillating Properties of Sol-Gel Eu3+, Tb3+ Co-Doped Lu2O3 Nanopowders

Nanocrystalline Eu3+, Tb3+ co-doped Lu2O3 powders with a maximum size of 25.5 nm were prepared by the sol-gel process, using lutetium, europium and terbium nitrates as precursors, and ethanol as a solvent. Differential thermal analysis (DTA) and infrared spectroscopy (IR) were used to study the chemical changes during the xerogel annealing. After the sol evaporation at 100 °C, the formed gel was annealed from 300 to 900 °C for 30 min under a rich O2 atmosphere, and the yielded product was analyzed by X-ray diffraction (XRD) to characterize the microstructural behavior and confirm the crystalline structure. The results showed that Lu2O3 nanopowders start to crystallize at 400 °C and that the crystallite size increases along with the annealing temperature. A transmission electron microscopy (TEM) study of samples annealed at 700 and 900 °C was carried out in order to analyze the microstructure, as well as the size, of crystallites. Finally, in regard to scintillating properties, Eu3+ dopant (5 mol%), Tb3+ codoped Lu2O3 exhibited a typical red emission at 611 nm (D°→7F2), furthermore, the effect of Tb3+ molar content (0.01, 0.015 and 0.02% mol) on the Eu3+ radioluminiscence was analyzed and it was found that the higher emission intensity corresponds to the lower Tb3+ content

Norme en goedkeuringsisteme vir grootskaalse kleinhandelinstellings

Hypermarkets and other large scale retail facilities are making deep inroads into the retail market. The location of large retail facilities has far-reaching consequences which are not confined to municipal boundaries. Yet there is no specific system in South Africa for processing applications for these types of facility. On the basis of an analyses of methods of control used locally and overseas a method that can be applied locally, is formulated. It is suggested that applications for retail facilities with a floor area of more than 20 000 m2  should be subject to a special control system. A metropolitan authority, most probably a regional services council, should,in the first instance consider the desirability of an application. After the granting of approval at this level the development may be controlled at local authority level through a development plan. This plan would be drawn up by the developer and approved by the local authority.*This article is written in Afrikaans

Fate of the organophosphate herbicide glyphosate in arable soils and its relationship to soil phosphorus status

Glyphosate is one of the world's most widely used herbicides. This study was undertaken to unravel the factors affecting its movement, sorption, persistence and leachability in different Finnish soils to create a sound basis for risk assessment. Field experiments indicated rather long persistence of glyphosate in Finnsih soils low in soil test P. The key soil factors promoting the persistence and reducing the leaching of glyphosate and its metabolite aminomethylphosphonic acid appeared to be low P status and high Al and Fe oxide contents in soil, leading to low degree of P saturation and to reduced biodegradability as result of strong sorption

Stads- streekbeplanning binne die konteks van 'n nasionale beleid vir omgewingsbestuur

The President's Council recently con­ducted an inquiry into a national en­vironmental management system. The comments of the Cape Branch of the South African Institute of Town and Regional Planners to the Council prompted the author to undertake an in depth analysis of the role of town and regional planning in environmen­tal protection. Threats to the environment span a wide spectrum of both scale and types. Many perceived 'threats' are based on subjective norms of desirability. The extent to which these cultural values are perceived to be threatened, depend on the background and income level of the observer. Town planning deals mostly with cultural value systems. The town planning process is particu­larly suited to address threats to the environment at the local and regional levels. It provides a well tested arbitra­tion process. In a democratic political system it is responsive to the real needs and aspirations of citizens. Structure plans are an ideal medium for making explicit the policy of a community on environmental mat­ters, but they lack enforceability. Where strong protection is needed, other measures must be invoked. The present lack of coordination between the local planning process and Acts of Parliament that could provide protec­tion, such as the Environment Conser­vation Act, is a major shortcoming that needs to be addressed. The role of central government departments, such as Environment Affairs, Planning and Provincial Affairs, the various 'own affairs' departments dealing with lo­cal government and the provincial ad­ministrations, in planning and en­vironmental protection need to be clarified. Ideally the public should only have to deal with a single system encompassing planning, development control and environmental protection at the local level. At the local level ur­ban planning and environmental pro­tection can not logically be separated. The role that the local planning pro­cess can play in environmental protec­tion should be brought to the attention of the public, environmental groups and the relevant government depart­ments.*This article is written in Afrikaans.&nbsp

Linkage of the current ALS-resistance status with field history information of multiple fields infested with blackgrass (Alopecurus myosuroides Huds.) in southern Germany

The repetitive use of herbicides as major tool to control troublesome weeds in agriculture caused an increase in resistant weeds lately, especially when Integrated Weed Management principles were ingnored. In a case study approach we sampled blackgrass (Alopecurus myosuroides Huds.) in three distinctive locations for at least 3 years. Based on field infestation level, greenhouse biotests and laboratory analyses we grouped 23 fields as resitant (R), 28 fields as less sensitive (I) and 39 fields as sensitive (S) with regard to their ALS resistance status. Field history information was collected for 90 fields. Variables regarding the frequency of 1) summer crops, 2) winter cerals, 3) ploughing, 4) herbicide use, and 5) early versus late seeding were calculated. Fields with a higher frequency of summer crops, ploughing and later sowing dates in the crop rotation were less frequently grouped into R and I. No relationship was found between the number of modes of action used and the resistance status. Intensity of ALS-inhibitor use of grass herbicides played a role to distinguish resistant from sensitive fields. Our results suggest that cultural measures to bring the blackgrass population size to lower levels are more important than the selection by the herbicide.Zusammenhang des ALS-Resistenzstatus bei Ackerfuchsschwanz (Alopecurus myosuroides Huds.) mit den durchgeführten Bewirtschaftungsmaßnahmen auf mehreren Feldern in SüddeutschlandDer übermäßige Einsatz von Herbiziden als einzige Maßnahme zur Reduzierung von Problemunkräutern hat in den letzten jahren zu einer Zunahme resistenter Unkrautpopulationen geführt. Im Rahmen einer Fallstudie wurde daher Ackerfuchsschwanzsamen (Alopecurus myosuroides Huds.) an 3 Standorten über einen Zeitraum von mindetstens 3 Jahren beprobt. Basierend auf einer Befallseinschätzung im Feld, Gewächshaustests und Laboranalysen wurden 23 Felder als resistent (R), 28 Felder als vermindert sensitiv (I) und 39 Felder als sensitive Felder (S) gegenüber ALS-Inhibitoren klassifiziert. In Interviews mit den Landwirten konnten die Bewirtschaftungsmaßnahmen für diese 90 Felder erfragt werden. Aus diesen wurden Variablen, die den Anteil an 1) der Sommerungen in der Fruchtfolge, 2) des Wintergetreides in der Fruchtfolge, 3) den Pflugeinsatz, 4) den Herbizideinsatz sowie 5) die Saatzeitpunktewahl repräsentieren, generiert. Mit einer Zunahme an Sommerungen in der Fruchtfolge, einem erhöhten Pflugeinsatz sowie der häufigeren Wahl später Saatterminewar eine geringere Häufigkeit an resistenten Feldern zu beobachten. Dagegen wurde kein Zusammenhang zwischen der Anzahl der eingesetzten Wirkstoffklassen und dem Resistenzstatus gefunden. Signifikante Unterschiede beim Einsatz von ALS-Inhibitoren waren nur zwischen S und R erkennbar. Unsere Ergebnisse zeigen, dass ackerbauliche Maßnahmen eine stärkere Wirkung auf die Resistenzentwicklung haben, als die Häufigkeit and Art des Herbizid-Einsatzes

25 Jahre Sulfonylharnstoff-Herbizide – ein paar Gramm veränderten die Welt der chemischen Unkrautbekämpfung

Mit der Entdeckung der herbiziden Wirkung bestimmter Sulfonylharnstoff-Verbindungen durch George Levitt (1. Patent 1978 für DuPont) und der nachfolgenden Entwicklung und kommerziellen Einführung entsprechender Herbizide (erster in Deutschland erhältlicher Wirkstoff im Jahr 1985 war Metsulfuron-Methyl, GROPPER®) erfolgte ein Quantensprung in der chemischen Unkrautbekämpfung. Die im Vergleich zu damaligen kommerziellen Standards um den Faktor 100 bis 1000 drastisch verringerten Aufwandmengen, der völlig neuartige Wirkmechanismus (Hemmung des Enzyms Acetolactatsynthase, ALS), die flexiblen Einsatzmöglichkeiten vom frühen bis zum späten Nachauflauf und die günstigen Anwender- und Umweltsicherheitsprofile dieser Herbizide setzten einen neuen Standard, der bis heute nicht übertroffen wurde. Insgesamt wurden von mehreren Firmen seitdem weltweit über 30 Moleküle aus dieser Chemieklasse entwickelt und registriert, mit Einsatzmöglichkeiten in praktisch allen Ackerbaukulturen; es folgten noch weitere Verbindungs-klassen it dem gleichen Wirkungsmechanismus.Sulfonylharnstoffe werden über Blatt und Wurzel aufgenommen und akropetal und basipetal in der ganzen Pflanze verteilt. Die spezifische Hemmung der Acetolactatsynthase blockiert die Biosynthese der verzweigtkettigen Aminosäuren Valin, Leucin und Isoleucin und damit die Proteinsynthese. Die Kulturselektivität spezifischer Sulfonylharnstoffe in den verschiedenen Ackerbaukulturen beruht auf einem raschen Metabolismus des jeweiligen Wirkstoffs. Der Abbau im Boden kann über mikrobielle und/oder chemische Prozesse erfolgen, wobei die Halbwertzeiten molekül-, boden- und klimaabhängig sind. Durch vieljährige einseitige Selektion entstandene Unkrautpopulationen mit Resistenzen gegen ALS-Hemmer weisen entweder spezifische Punktmutationen am Zielenzym ALS oder einen beschleunigten Metabolismus des Wirkstoffs auf.Für eine erfolgreiche chemische Unkrautbekämpfung in der gesamten Fruchtfolge sind die Sulfonylharnstoffe im Zusammenhang mit der Verfügbarkeit anderer herbizider Wirkstoffklassen zu betrachten. Die Zukunft der bestehenden Wirkstoffe und die Aussicht auf weitere grundlegende Neuerungen im Bereich der Herbizide wird von der weiteren Entwicklung der Herbizidresistenztechnologien aus Kulturpflanze und Komplementärherbizid sowie dem Auffinden neuer Wirkungsmechanismen abhängen. Auch der zunehmende Anteil bewährter Altwirkstoffe, die preiswert verfügbar bleiben, beeinflusst über die Wirtschaftlichkeitsbetrachtung den Aufwand und Erfolg der Suche nach neuen Wirkungsmechanismen.Stichwörter: Acetolactatsynthase, ALS-Hemmer, Herbizidresistenz, Sulfonylharnstoff25 years of sulfonylurea herbicides – a few grams changed the world of chemical weed controlWith the discovery of herbicidal activity of certain sulfonylurea compounds by George Levitt (first patent awarded to DuPont in 1978) and with the subsequent development and commercialization of herbicides from this class (i.e. Metsulfuron-Methyl, GROPPER®, first registered as a product in Germany in 1985) a quantum leap in herbicide technology was achieved. The drastically reduced use rates (by a factor of 100- to 1000-fold compared with standard products of the time), the entirely new mechanism of action (inhibition of the ALS enzym), flexible application (pre- or post-emergent), and the outstanding safety to the applicator and the environment set a new standard for herbicides, which even today has not been superseded. A total of over 30 molecules have been commercialized from this class world-wide, with uses in practically all major row crops. Several additional structural subclasses with the same mode of action have followed. Sulfonylureas enter plants through foliar and soil uptake and are translocated acropetally and basipetally within the plant. The mechanism of action is through the inhibition of the acetolactate synthase enzyme, blocking the synthesis of the branched chain amino acids valine, leucine and isoleucine, and thus inhibiting protein synthesis. Selectivity is achieved through the rapid metabolism of the active substance to inactive metabolites within the crop before it can act. Sulfonylureas degrade in soils mainly through microbial action or through chemical hydrolysis; degradation rates and pathways are specific to the molecule, soil and climate. Selection of resistant individuals through continuous application of sulfonylurea herbicides over many years led to the development of resistant weed populations that possess specific point mutations in the ALS enzyme, or the ability to rapidly metabolize the active ingredient.The sulfonylureas must be compared with other important classes of herbicides as components of a sustainable weed management system within various crop rotations. The future of existing herbicide classes and the prospects for future basic advances in weed management technologies depend on the further development of technologies to counter herbicide resistance (crops and complementary herbicides), and the discovery of herbicides with novel modes of action. Keywords: Acetolactate synthase, ALS inhibitor, herbicide resistance, sulfonylure

Esmilo/Mediq: toetsingskader voor nietigheid ex art. 3:40 lid 1 BW

__Abstract__ Recent heeft de Hoge Raad het arrest Esmilo/Mediq gewezen, waarin de vraag speelt wanneer een overeenkomst die een verboden strekking heeft of verplicht tot een bij wet verboden prestatie op grond van art. 3:40 lid 1 Burgerlijk Wetboek (BW) nietig is.1 Dit arrest staat in deze bijdrage centraal. De stand van zaken vóór dit arrest bespreken wij in paragraaf 2. In paragraaf 3 geven wij de kern weer van Esmilo/Mediq. Vervolgens zal in paragraaf 4 het arrest nader worden besproken. Eerst zullen wij kort ingaan op art. 3:40 BW

Herbicide resistance in German and Swiss Lolium spp. populations - resistance factors and cross-resistance spectrum

In monitoring trials investigating the occurrence  and spread of herbicide resistance in German and Swiss Lolium populations 26 samples could be included since 2008. Biotypes which showed  resistance to post­ emergence herbicides were included into a detailed greenhouse trial in 2014. Based an dose-response experiments, resistance factors and cross resistance patterns for cycloxydim, flufenacet, glyphosate, iodosulfuron, meso- and iodosulfuron, pinoxaden and pyroxsulam could be determined. Resistance to ALS as weil as ACCase inhibitors was found. In a few cases also resistance to Aufenacet could be detected. Incontrast, no resistance to glyphosate was discovered. Resistant populations were found in four German federal states (Hessen, Mecklenburg-Vorpommern , Sachsen and Schleswig-Holstein).Two populations were resistant to all cereal selective post-emergence herbicides and to flufenacet. Same populations from Switzerland indicated presence of ACCase inhibitor resistance. In the future, more problems with herbicide resistant Lolium species as weeds in cereals may arise due to limited amount of available selective herbicides and climatic change with more favourableconditions for Lolium spp. as weeds.Herbizidresistenz in Lolium spp. aus Deutschland und der Schweiz - Resistenzfaktoren  und KreuzresistenzmusterIn Monitoringversuchen zur Verbreitung der Herbizidresistenz wurden seit 2008 26 Lolium-Herkünfte mit Resistenzverdacht aus Deutschland und der Schweiz untersucht. Herkünfte, die sich als resistent erwiesen, wurden in 2014 in einen weiteren Gewächshausversuch eingehender untersucht. Durch Dosis-Wirkungs-Experimente wurden Resistenzfaktoren und Kreuzresistenzmuster für die Wirkstoffe Cycloxydim, Flufenacet, Glyphosat, Iodosulfuron, Meso-+Iodosulfuron, Pinoxaden und Pyroxsulam bestimmt. Resistenzen traten bei ALS- und/oder ACCase-Hemmern auf. Bei einigen Herkünften wurde einedeutliche Resistenz gegen Flufenacet festgestellt. Alle Herkünfte erwiesen sich als sensitiv gegenüber Glyphosat. Resistente Herkünfte kamen aus Schleswig-Holstein, Mecklenburg-Vorpommern, Sachsen und Hessen. Zwei Herkünfte erwiesen sich als besonders widerstandsfähig   und  konnten durch alle registrierten getreideselektiven Herbizide nicht mehr kontrolliert werden. Einige Herkünfte aus der Schweiz wiesen Resistenzen gegen ACCase-lnhibitoren auf. Mit einer Ausweitung herbizidresistenter Lolium-Biotypen muss aufgrund des nur eingeschränkt möglichen Wirkstoffklassenwechsels, der  klimatischen Bedingungen und veränderter Ackerbausysteme zukünftig gerechnet werden