Dissertations / Theses on the topic 'Van Sommer'

Representational flexibility is usually assessed in the graphic domain by whether children can innovate canonical drawings. According to the Karmiloff-Smith’s RR Model (RRM 1990), flexibility is acquired with a marked discontinuity at 8-9 years, when routine drawings are overcome once and for all. RRM, though, is inherently recursive, implying that innovation entertains a continuous trade-off with graphic conservatism along development. In this regard, a less recent model by van Sommers (1984) suggests that pictorial conservatism coexist with flexibility, even in adulthood, and that continuity models fit better flexibility development. This study aims at comparing the two models and their ability to predict the relationship between conservatism and flexibility during development. 75 children (5, 7, 9, 11 year-olds) and 20 adults were asked to draw two similar and two different houses (administration order balanced across the sample). Drawings were coded with a 5 point scale for 6 aspects (e.g. house’s structure and details). Results show that linear trends fit flexibility development in all aspects. Adults draw canonical houses more than older children, although score highly in the differentiation task. Results suggest that flexibility coexist with some conservatism even in adults, lending support to van Sommers’s model, in these regards.

Les développements actuels de la méthode de Van der Corput pour les sommes d'exponentielles font apparaître la nécessité d'apporter des précisions aux transformations de base A et B. La première partie de cette thèse constitue une étude complète de la transformation B simple; le cas des sommes d'exponentielles avec paramètre est également étudié. Dans la deuxième partie, nous étudions un nouveau procédé de majoration pour les sommes simples d'exponentielles qui consiste à adapter la méthode de Fouvry et Iwaniec à celle de Van der Corput. Les résultats obtenus viennent compléter un tableau de Huxley. Enfin, la troisième partie reprend en détail le lemme de la phase stationnaire, le résultat obtenu donne une estimation (probablement) optimale pour les moyennes d'intégrales oscillantes en vue d'applications à la transformation B simple, double et multiple
In modern methods for analytic exponential sums theory, the A and B Van der Corput's process occur in various forms where more accuracy is needed. The' first part of this thesis achieves a complete study of B process for single exponential sums or sums with a parameter. In the second part, Fouvry and Iwaniec's method for multiple exponential sums with monomial is combined with A and B Van der Corput's process to get new bounds for single exponential sums which complete Huxley's table. The third part gives an accurate estimation for single oscillating integrals when the critical point is close to the endpoints of the integration interval which applies to mean values of oscillating integrals such as those that occur in the study of multiple B transform

Le travail présenté dans cette thèse tend à faire un premier pas vers l’utilisation de l’optique non linéaire dans le contexte interférométrique de la synthèse d’ouverture en astronomie optique. L’objectif principal de ce travail consiste à caractériser expérimentalement un phénomène d’interférences de signaux infrarouges en transférant les propriétés vers les signaux convertis dans le domaine visible par somme de fréquences. Les signaux infrarouges seront mélangés avec un laser de pompe monochromatique et polarisé rectilignement à 1,064 μm dans un cristal non linéaire PPLN (Niobium de Lithium à polarisation périodiquement inversée) de type massif ou guide d’onde afin d’être converti à une longueur d’onde de 632 nm. Cette opération est effectuée en entrée des deux voies d’un interféromètre fibré. Les signaux convertis sont ensuite recombinés, mélangés et comparés aux résultats obtenus par un interféromètremonté en parallèle et travaillant directement à la longueur d’émission des sources infrarouges à 1,55 μm. Dans la pratique, nous avons effectué nos expériences dans une configuration des plus simples afin de mesurer la cohérence temporelle puis spatiale des sources en analysant les signaux convertis. Tout d’abord nous avons utilisé un rayonnement bi-fréquences centré autour 1,55 μm avec un faible écart spectral pour démontrer expérimentalement le transfert de la cohérence temporelle par somme de fréquences, conséquence du théorème de Wiener Kinchine. Dans un deuxième temps, nous avons utilisé un doublet spatial à 1,55 μm pour démontrer expérimentalement le transfert de la cohérence spatiale, conséquence du théorème de Zernike Van Cittert
The main scope of the present thesis is to pave the way for the use of non-linear optics in the context of interferometric synthetic aperture in astronomy. The principal achievement is the experimental characterization of the interference of infrared signals with an interferometer working at visible light. This fact is made possible through the use of a nonlinear up-conversion mechanism which preserves the information of the phase front of the signal. The infrared signals at 1,550 μm have been mixed with a common monochromatic pump laser linearly polarized at 1,064 μm in periodically poled Lithium Niobate crystals. Either bulk crystals or waveguides have been used to obtain final up-converted radiations at 632 nm. The simplest case of stellar interferometer combines the radiation of two telescopes. To replicate the same observation at visible wavelengths, we used two distinct up-conversion stages driven by a common pump. The up-converted signals are then recombined andmixed. Such results have been systematically compared with those obtained by a parallel experimental setup based on an infrared interferometer working as a reference. We have focused our experiments to very simple and archetypal configurations in which we measured their temporal or spatial coherence by analyzing the up-converted radiations. In a first set of experiments the signal was composed by a doublet of closely spaced frequencies a bi-frequency radiation centered around 1. 55 μm with a low spectral gap. Our scope was to demonstrate experimentally that the up-converion by sum frequency generation keeps preserved the temporal coherence, as a consequence of theWiener Kinchine theorem. In a second set of experiments, we used a spatial doublet at 1. 55 μm to demonstrate that the same wavelength up-conversion also preserves the spatial coherence, as predicted by the corresponding theorem of Van Cittert Zernike

Ancient medicine is a fast-growing field of research at international level, but since successful research implies both medical (or pharmaceutical) knowledge and the ability to read Latin and Greek, only one classicist in South Africa has published on the topic in co-operation with a medical doctor. Although the professional and scholarly literature on ancient Greek and Roman medicine has proliferated in the last few decades, few studies have appeared that focus on narcotics and analgesics, their effects as observed and recorded by physicians, pharmacologists, and medical botanists, and an evaluation according to modern pharmacology or phytochemistry.1 The study is especially topical in the light of the modern-day search for herbal medicines and the renewed interest in South African ethno botanical traditions (e.g. Afrikaner, Zulu, Swazi) as opposed to chemically prepared narcotics. Phytochemical properties of crude drugs have predictable physiological effects in the living human organism. Therefore, presuming that humans have not changed except incrementally in their physiological chemistry over the short span of two millennia, one can likewise document the effects of narcotics and analgesics in Graeco-Roman pharmacology, provided that the botanical sources and their manufactured forms are carefully identified. A secondary assumption is that ancient plants also carried phytochemical properties generally identical to modern ones, so that the descriptive nomenclatures of modern botany and phytochemistry reveal multiple pharmacological principles and their actions in ancient drugs, as well as their potentially undesirable side effects. 1. One of the exceptions is the 1995 "The Opium Poppy in Hellenistic and Roman Medicine" by Prof. John Scarborough (in Roy Porter and Mikulas Teich, eds., Drugs and Narcotics in History [Cambridge and New York: Cambridge University Press]).
Thesis (Ph.D. (Latin))--North-West University, Potchefstroom Campus, 2009.

1. DIE DOEL VAN DIE NAVORSING: Die doel van hierdie navorsing was om die beste voorspellers van akademiese prestasie (dit is persentasie slaag) onder die kognitiewe, affektiewe en skoolveranderlikes vas te stel. Die teikengroep het uit standerd 10 leerlinge in Kwazulu skole bestaan. 2. DIE BEVINDINGE UIT DIE LITERATUUR: Om die voorgemelde doel te bereik 1s die oorsig van literatuur met verwysing na die vermelde onafhanklike veranderlikes gedoen, en die volgende gevolgtrekkings is bereik. 2.1 DIE VOORSPELLINGSWAARDES VAN DIE KOGNITIEWE VERANDERLIKES: Betreffende die voorspellingswaarde van die kognitiewe veranderlikes, het die literatuur daarop gewys dat die kognitiewe veranderlikes ongeveer 25 persent van die variansie in die akademiese prestasie verklaar. Belangrik in hierdie verband is die bevindinge deur Lavin (1967), Bloom (1979) en talle ander wat die voorspellingswaarde van intelligensie en aanleg ondersoek het. Die ander belangrike bevinding, in verband met intelligensie as voorspeller van akademiese prestasie, is dat die voorspellingswaarde van intelligensie daal as die leerlinge die hoer klasse bereik. Met ander woorde, intelligensie is volgens die literatuur 'n goeie voorspeller van akademiese prestasie in die primêre klasse. Sowel Lavin (1967) as Jensen (1980) het hierdie bewering gemaak. Die voorspellingswaarde van vorige deur die literatuur te bestudeer. literatuur daarop gewys dat voorspeller van akademiese prestasie is. Wat aanleg as voorspeller van akademiese prestasie betref, wys die literatuur daarop dat variansie wat grater as 25 persent in akademiese prestasie is, verklaar kan word op grond van aanleg. In hierdie verband kan die werke van Von Mollendorf (1978) en Vander Westhuizen (1987) genoem word. 2.2 DIE VOORSPELLINGSWAARDE VAN DIE AFFEKTIEWE VERANDERLIKES: Die affektiewe veranderlikes wat hier betrokke is, is persoonlikheid en beroepsbelangstelling. Betreffende die voorspellingswaarde van persoonlikheid is teenstrydige bevindinge in die literatuur verkry. Enersyds het ondersoeke wat in Amerika gedoen is, getoon dat die byvoeging van die persoonlikheidsveranderlikes by die kognitiewe veranderlikes in die voorspelling van akademiese prestasie 'n toename in die verklaring van variansie meebring. Andersyds het die navorsing wat in Suid-Afrika gedoen is, nie 'n duidelike beeld gegee nie. In die algemeen het die Suid-Afrikaanse ondersoeke daarop gewys dat die persoonlikheidsveranderlikes van min waarde is in die voorspelling van akademiese prestasie. Uit die studie van die literatuur, betreffende die voorspellingswaarde van beroepsbelangstelling, het dit geblyk dat beroepsbelangstelling van minder waarde is in die voorspelling van akademiese prestasie is as beroepsbelangstelling. 2.3 DIE VOORSPELLINGSWAARDE VAN DIE SKOOLVERANDERLIKES: Die skoolveranderlikes is in twee groepe verdeel: die fisiese wat skoolgrootte, klasgrootte, skoolligging en skool fasiliteite behels, en die sosiale wat die prinsipaal en die onderwysers behels. Die oorsig van die literatuur het daarop gewys dat die fisiese fasiliteite belangrik is vir opvoeding, maar hulle uitwerking op die kwaliteit van onderrig afhanklik is van hulle benutting deur die onderwysers. Byvoorbeeld, kleiner klasse het nie beduidend bygedra tot beter prestasie as die grater klasse nie. Die gevolgtrekking wat deur Bloom (1976) onder andere, bereik is, is dat die hele skoolomgewing belangrik is vir onderrig en n1e net die fisiese fasiliteite nie. Ongeveer 5 persent van die variansie in akademiese prestasie is volgens Bloom (1979) deur die skool verklaar. Dit was om hierdie rede dat die hele skool in hierdie ondersoek bestudeer is. Literatuur het ook deurgaans daarop gewys dat die verskille tussen die skole in akademiese prestasie verdwyn as intelligensie en die sosio-ekonomiese status gekontroleer is. 2.4 DIE INVLOED VAN GESLAG OP AKADEMIESE VOORSPELLING: Die literatuur het daarop gewys dat die twee geslagte se akademiese prestasie verskil. Die dogters, byvoorbeeld, presteer beter as seuns in toetse wat verbale aanleg verg, terwyl die seuns beter as dogters in wiskunde presteer: Die twee geslagte het geen verskille in intelligensie getoon nie. 3. DIE EMPIRIESE ONDERSOEK 3.1 DIE FORMULERING VAN HIPOTESES: 3. 1. 1 Hoof hipotese HOOF HIPOTESE 1 - Die aanleg veranderlikes is die beste voorspellers van standerd 10 akademiese prestasie in vergelyking met die affektiewe en die skoolveranderlikes. HOOF HIPOTESE 2 - Die affektiewe veranderlikes bring 'n toename mee in die variansie wat verklaarbaar is in akademiese prestasie as dit by die kognitiewe veranderlikes bygevoeg word. HOOF HIPOTESE 3 - Die skoolveranderlikes bring 'n toename mee in die variansie wat verklaarbaar is in akademiese prestasie as dit by die kognitiewe veranderlikes bygevoeg word. 3.1.2 Onderhipotese ONDERHIPOTESE 1 - Die gehalte van die skool het beduidende invloed op die voorspelling van akademiese prestasie in standerd 10. ONDERHIPOTESE 3 - Die ligging van die skool het 'n beduidende invloed op die voorspelling van akademiese prestasie in standerd 10. ONDERHIPOTESE 4 - Skoolsoort het 'n beduidende invloed op die voorspelling van akademiese prestasie in standerd 10. ONDERHIPOTESE 5 - Geslag het 'n beduidende invloed op die voorspelling van akademiese prestasie in standerd 10. ONDERHIPOTESE 6 - Daar bestaan steeds 'n verskil tussen koshuis en dagskole in akademiese prestasie selfs as aanleg gekontroleer is. ONDERHIPOTESE 7 - Daar bestaan steeds 'n verskil tussen stedelike en plattelandse skole in akademiese prestasie selfs as aanleg gekontroleer is. 3.2 DIE EMPIRIESE ONDERSOEK: Die empiriese ondersoek is ingestel om die geformuleerde hipoteses te toets. 3.2.1 Die teikengroep en die steekproef Die KwaZulu 1983 standerd 10 leerlinge is die teikengroep. Om die invloed van die ~kool op voorspelling vas te stel is 'n 10 persent ewekansige steekproef uit 170 sekondêre skole geneem (dit is 17 skole). As gevolg van die ewekansige steekproef is 'n monster van 1912 leerlinge gevorm. Die vermindering van die steekproef tot 1615 leerlinge in sommige analises, is 'n gevolg van onvolledige data van sekere leerlinge. 3.2.2 Die veranderlikes wat gebruik is 3.2.2.1 Die onafhanklike veranderlikes wat in hierdie ondersoek gebruik is, is die volgende: a. Aanlegtoetsresultate (AAT) b. Persoonlikheidsresultate (HSPQ) c. Belangstellingsresultate (VIQ) d. Skoolveranderlikheidstotaal (SVTOT) 3.2.2.2 Die afhanklike wat in hierdie ondersoek gebruik is, is die volgende: e. Standerd 10 geslaag persentasie. 3.2.2.3 Die modererende veranderlikes wat in hierdie studie bestudeer is, is die volgende: f. Die skoolgehalte; g. Die vakgroepe wat die leerlinge leer; h. Die ligging van die skool (stedelik of plattelands); i. Skooltipe (koshuis of dag); en j. Geslag. In hierdie ondersoek is gebruik gemaak van gestandardiseerde meetinstrumente om kognitiewe, en affektiewe veranderlikes te meet. Om die "skool" te meet is verskeie skoolveranderlikes eers geoperasionaliseer en daarna punte volgens rangorde deur die inspekteurs toegeken. Geslag is in hierdie ondersoek as modererende veranderlike gebruik om die invloed daarvan op voorspelling te bestudeer. Om die invloed van die skool as 'n modererende veranderlike te bestudeer is die steekproef verder verdeel volgens skoolgehalte, skoolligging en skooltipe. Die leerlinge was ook gegroepeer volgens die vakgroepe wat hulle geneem het (dit is algemeen, natuurwetenskap en handel). 4. STATISTIESE TEGNIEKE WAT IN HIERDIE NAVORSING GEBRUIK IS EN DIE RESULTATE VAN DIE ONDERSOEK: 4.1 MEERVOUDIGE REGRESSIE-ANALISE: Deurgaans toegepas is die meervoudige regressie-analise (BMDPIR program) om die beste voorspellers van akademiese prestasie te identifiseer. Die resultate van die analise het daarop gedui dat: i. die kognitiewe veranderlikes die beste voorspellers van akademiese prestasie is, in vergelyking met die affektiewe en die skoolveranderlikes; ii. die affektiewe veranderlikes van min voorspellingswaarde is; en iii. die skoolveranderlike 'n beduidende effek op voorspellings het. As gevolg van meervoudige regressie-analise is die kognitiewe en skoolveranderlikes gebruik as kontrole veranderlikes in die moderatorveranderlike studie. Die affektiewe veranderlikes is weggelaat weens hulle geringe bydrae tot R2 . 4.2 VARIANSIE ANALISE: Die meervoudige regressie-analise (BMDPIR) is ook gebruik by die moderatorondersoek. Die resultate van die ondersoek het daarop gedui dat: i. die skoolgehalte 'n beduidende invloed op die voorspelling van akademiese prestasie het; ii. die vakgroepe wat leerlinge leer 'n beduidende invloed op akademiese voorspelling het; iii. die skoolligging 'n beduidende invloed op akademiese voor spelling het; iv. die skooltipe 'n beduidende invloed op akademiese voorspelling het; v. geslag geen beduidende invloed op die voorspelling van algehele akademiese prestasie het nie; vi. die verskil in akademiese prestasie tussen die koshuisskole en dagskole bly steeds dieselfde selfs as aanleg gekontroleer is; en vii. die verskil in die akademiese prestasie van stedelike en plattelandse leerlinge steeds dieselfde bly selfs as aanleg gekontroleer is. 5. IMPLIKASIES VIR VERDERE ONDHRSOEK: In hierdie studie is gevind dat aanleg 'n goeie voorspeller van akademiese prestasie in goeie skole is, maar nie in swak skole nie. 'n Geldigheidsstudie is nodig om swak voorspelbaarheid in swak skole vas te stel. Sulke geldigheidstudies moet die sistematiese veranderlikes ook bestudeer sodat hulle invloed op R2 verklaar kan word. In hierdie studie is ook gevind dat die plattelandse skole akademies beter as stedelike skole presteer. Die bevinding is teenstrydig met die bevindinge van die vorige navorsers. 'n Verdere studie is dus ook nodig om die bevindinge van hierdie studie te bevestig of te verwerp. Die moontlikheid bestaan dat hierdie bevinding die invloed van die onrus wat gedurende daardie jare plaasgevind het, weerspieël. Verdere navorsing is ook nodig om die invloed van die groepvakke op akademiese prestasie te bevestig en o.a. die geldigheid van die resultate van hierdie navorsing te toets. Verdere navorsing is nodig om die waarde van die insluiting van 'n toets in moedertaal in die AAT battery vir voorspellings van akademiese prestasie vas te stel. Die resultate van hierdie studie (kyk tabel 6 • 2 ) het getoon dat die AAT die swakste met Zulutaal korreleer. 'n Toets in moedertaal blyk dus nodig te wees. 6. OPVOEDKUNDIGE IMPLIKASIE: Die kruisvalidasie van die beste stelveranderlikes het daarop gewys dat dit goed by goeie skole kan voorspel en nie by swak skole nie. Om al die skole se akademiese prestasie te verbeter, word dit aanbeveel dat die toetse aan die begin van die jaar toegepas moet word en dat die nuwe snitpunte (kyk paragraaf 6.7) by die verwagtingstabel gebruik moet word. Die vroegtydige beskikbaarheid van die toetsresultate kan help om leerlinge en die onderwysers te motiveer om beter te presteer.
Thesis (MEd)--PU vir CHO, 1989

Denna studie behandlar hur lärare undervisar i naturvetenskap och vilken didaktik de använder. Det finns många synpunkter kring hur den naturvetenskaplig undervisning bör vara utformad, men fungerar teorierna i praktiken? Vad tror pedagogerna på fältet, som vi talat med? Vad är en effektiv inlärningsmetod? Hur formar man som pedagog sin undervisning efter sina elevers erfarenheter och hur utvecklar kan de hjälpa eleverna att få en djupare förståelse för naturvetenskapliga fenomen? Det är vad denna studie kommer att handla om. Vårt syfte är att belysa att det finns många olika sätt och perspektiv på den naturvetenskapliga didaktiken. Vi har använt oss av kvalitativa intervjuer av pedagoger ute i verksamheterna som alla har något att delge av hur de praktiserar sin didaktik och hur de ser på elevers lärande inom de naturvetenskapliga områdena.

Many physical phenomena can be described by nonlinear models. The last few decades have seen an enormous growth of the applicability of nonlinear models and of the development of related nonlinear concepts. This has been driven by modern computer power as well as by the discovery of new mathematical techniques, which include two contrasting themes: (i) the theory of dynamical systems, most popularly associated with the study of chaos, and (ii) the theory of integrable systems associated, among other things, with the study of solitons. In this dissertation, we study two nonlinear models. One is the 1-dimensional vibrating string satisfying wtt − wxx = 0 with van der Pol boundary conditions. We formulate the problem into an equivalent first order hyperbolic system, and use the method of characteristics to derive a nonlinear reflection relation caused by the nonlinear boundary conditions. Thus, the problem is reduced to the discrete iteration problem of the type un+1 = F (un). Periodic solutions are investigated, an invariant interval for the Abel equation is studied, and numerical simulations and visualizations with different coefficients are illustrated. The other model is the Korteweg-de Vries-Burgers (KdVB) equation. In this dissertation, we proposed two new approaches: One is what we currently call First Integral Method, which is based on the ring theory of commutative algebra. Applying the Hilbert-Nullstellensatz, we reduce the KdVB equation to a first-order integrable ordinary differential equation. The other approach is called the Coordinate Transformation Method, which involves a series of variable transformations. Some new results on the traveling wave solution are established by using these two methods, which not only are more general than the existing ones in the previous literature, but also indicate that some corresponding solutions presented in the literature contain errors. We clarify the errors and instead give a refined result.

Being a skilled reader makes it easier to learn a new language. It is important to teach students how the knowledge and use of reading strategies can facilitate learning. This study was made in a Swedish fourth grade class with eighteen participant pupils. They were asked to translate two texts from English into Swedish: one was a poem with nonsense words, and the other a prose text. The texts were taken from Through the Looking Glass by Lewis Carroll and The Garbage King by Elizabeth Laird. After this an interview was made with all of the pupils in pairs, where they were asked about their reading strategies normally and in this situation. The results found were that the reading strategies used were: likeness with their native language, previous vocabulary knowledge of the L2, syntactic knowledge, and guessing the meaning through the context. The result confirms previous research in that the pupils who liked reading and did so in their spare time, did better when it came to making syntactically correct translations.

The effects of nitric oxide (NO) and histamine as modulators of neuromuscular transmission in the mouse vas deferens have been studied. Controls exerted by these agents have not previously been identified in this tissue. A pharmacological approach was taken to investigate the various activities of NO. The presence and identity of histamine receptors in this tissue was also determined by this method. The use of specific antagonists also showed that histamine is secreted during nerve stimulation. Contractions evoked by low frequency (5Hz) electrical nerve stimulation (5-50V) were recorded to give information about pre and postjunctional effects. Contractions evoked by the agonists noradrenaline or alphabeta-methylene ATP (alphabeta-met. ATP) gave information about postjunctional responses. Intracellular and focal recording techniques recorded evoked electrical activity (EJPs and EJCs); these reflect the neuronal release of ATP. Quantal analysis of EJC amplitudes permitted pre and postjunctional effects to be determined. Sodium nitroprusside (4x10-6m) depressed nerve evoked contractions suggesting a NO sensitivity. These contractions were also depressed by L-arginine (L-Arg), the natural precursor of NO. The nitric oxide synthase (NOS) inhibitor L-arginine methyl ester (L-AME) (2.3x10-4m), caused all mechanical responses to increase in amplitude suggesting a physiological depressive role for NO synthesis. An elevation of EJC amplitudes by L-AME (2.3x10-4m) was rapidly reversed by L-Arg (3.4x10-4m) suggesting that endogenous NO normally depresses ATP secretion. In the longer term L-Arg (3.4x10-4m) revealed a new RB2 sensitive low-threshold current of positive sign. L-Arg (3.4x10-4m) may have degranulated mast cells. This histamine may have been taken up and released as a neuro-transmitter. Thioperamide (6x10-6m) and ranitidine (1x10-4M) showed that endogenous histamine acts at H3 and H2 receptors to depress contractions but not those evoked by exogenous a?-met. ATP. Exogenous histamine (1x10-6M) also depressed EJC amplitudes by a physiological mechanism. The results showed that nitric oxide is a modulator of transmission in this tissue which depresses pre and postjunctional activities. Endogenous histamine also modulates transmission processes with effects similar to those of NO.

Validamycin A (Val-A) is an aminoglycoside's antibiotic with anti-fungal activity. Val-A synthesized by Streptomyces hygroscopicus strain depending on the growth and development of this actinomyces. In this study, the effects of Mn and Zn on the antifungal activity and biomass of the Streptomyces hygroscopicus were conducted. The results showed that micronutrients Mn, Zn had significant effects on biomass as well as antifungal activity of strain Streptomyces hygroscopicus- DA15. With the addition of Mn at a concentration of 1μg/l of the nutrient medium, biomass of Streptomyces hygroscopicus was 2.85±0.02g/ml, the anti-fungal Rhizoctoniasolani (R. solani) round diameter reached 3.5±0.2cm. With the addition of Zn=3μg/l of the nutrient medium, biomass of Streptomyces hygroscopicus DA15 was 4.5±0.02g/ml, the anti-fungal R. solani round diameter reached 3.4±0.2cm.
Validamycin A (val-A) là một loại kháng sinh có khả năng kháng nấm, được tổng hợp bởi xạ khuẩn Streptomyces hygroscopicus và phụ thuộc vào quá trình sinh trưởng, phát triển của xạ khuẩn. Bài báo này đánh giá ảnh hưởng của nguyên tố vi lượng Mn, Zn đến hoạt tính kháng nấm Rhizoctonia solani (R. solani) và sinh khối của chủng Streptomyces hygroscopicus DA15. Khi bổ sung Mn vào môi trường nuôi cấy với nồng độ 1μg/l, sinh khối của Streptomyces hygroscopicus- DA15 đạt 2,85±0,02g/ml, đường kính vòng kháng nấm đạt 3,5±0,2cm. Bổ sung Zn vào môi trường nuôi cấy với hàm lượng Zn=3μg/l, sinh khối của Streptomyces hygroscopicus DA15 đạt 4,5±0,02g/ml và đường kính vòng kháng nấm đạt 3,4±0,2cm.

Le Syndrome d’Apnée Obstructive du Sommeil affecte 4 à 6 % de la population en France soit près de 3 millions de personnes. Toutefois, les techniques de diagnostic usuelles ne permettent pas de déterminer de façon précise les sites d’occlusion ni de décrire les interactions fluide-paroi qui jouent un rôle important dans les processus de fermeture des voies aériennes supérieures. Au cours de ce travail, un ensemble d’outil a été mis en œuvre pour explorer les mécanismes sous-jacents conduisant à une apnée obstructive. La détermination géométrique et la caractérisation mécanique des voies aériennes supérieures, d’une part, la mesure des écoulements dans ces dernières, d’autre part, ont été réalisées par imagerie par résonance magnétique de l’hydrogène, pour les tissus, de l’hélium-3 et du fluor-19 pour les gaz. Les données obtenues ont été exploitées tout d’abord dans un modèle numérique statique pour estimer les lois d’état locales et caractériser la compliance des voies aériennes supérieures, puis, dans un modèle monodimensionnel, prenant en compte l’interaction fluide-structure et la limitation de débit au cours de l’inspiration, pour localiser les sites potentiellement responsables d’un éventuel collapsus. Par ailleurs, les écoulements de gaz d’hélium-3 et d’hexafluorure de soufre ont été simulés afin de déterminer le potentiel de ces deux modalités d’imagerie de gaz pour l’étude des obstructions des voies aériennes. La faisabilité d’une imagerie statique et dynamique par résonance magnétique du fluor a été démontrée. Avec une densité du gaz traceur bien plus importante, cette dernière technique présente une plus grande sensibilité à l’obstruction. Cette thèse ouvre ainsi une nouvelle voie de diagnostic et de guide thérapeutique personnalisé pour ce syndrome
Obstructive Sleep Apnea (OSA) is a common disorder occurring in almost 3 million French people. However, current diagnosis methods are not sufficient to precisely define obstructing sites and doesn't take into account the fluid structure coupling which plays an important role during upper airway closing. During this thesis, we developed a series of tools exploring upper airway closing process. On the one hand, a screening tool of the structure and the mechanical properties of the upper airway, and on the other hand, a screening tool exploring with dynamic images of inert gases flow into the upper airway, were obtained using conventional hydrogen MRI coupled to magnetic resonance elastography (MRE) and helium-3 or fluor-19 gases MRI, respectively. Geometric and biomechanical data obtained using MRI/MRE are injected into a numerical model given the compliance and the state law of upper airway. Contributions of anatomical restriction on airway collapse are also investigated using a multi-compartmental two-dimensional fluid structure interaction model during a breath inspiration to predicted airway mechanical changes and collapse pressures. Furthermore, helium 3 and sulfur hexafluoride flow was modeled at steady state using commercial finite volume software to evaluate potential feasibility to image upper airway collapsibility during OSA. First dynamic MR imaging using sulfur hexafluoride (SF6) was obtained showing the feasibility of this technique. Using SF6, 6 times denser than air, shows a higher sensibility to upper airway obstruction. This thesis opens a new imaging modality to probe and to diagnose upper airway obstruction

An investigation of the interaction of stable opioid/ligands and unstable opioid peptides with opioid receptors in guinea pig brain, guinea pig myenteric plexus and mouse vas deferens has been carried out. The initial aim of the study was to further characterise K opioid receptors, using binding assays and isolated tissue bioassays. The second aim was to determine the true affinity and potency of small dynorphin peptides for the K opioid receptor and to determine if metabolism of the peptides to non K opioid receptor-preferring products contributes to their observed in vitro pharmacology.

Relationships between net primary production and tree canopy parameters were investigated in 30 unmanaged stands of lodgepole pine (Pinus contort a var. I atifolia Engelm.) growing on sites with two contrasting hygrotopes (soil moisture regimes) and two contrasting trophotopes (soil nutrient regimes) in southeastern British Columbia. Sampled stands were between 50 and 130 years-of-age. Estimates of aboveground production (ANPP) were obtained for all 30 stands, and estimates of total (aboveground plus belowground) production (TNPP) were obtained for four stands. ANPP ranged from 2.2 to 4.4 t ha⁻¹yr⁻¹ for the xeric hygrotopes and from 2.9 to 7.4 t ha⁻¹yr⁻¹ for the sites with mesic hygrotopes. Variation in ANPP was explained by variation in stand foliage biomass, stand density, and age. Multiple regression equations fitted to data from each hygrotope differed significantly (a=0.05). The higher rates of ANPP observed in stands from mesic sites were attributed to the larger quantities of foliage biomass and to greater ANPP per kg of foliage (Foliage Efficiency) than in stands from the xeric sites. Total net primary production ranged from 7.9 to 11.9 t ha⁻¹yr⁻¹ in four stands. Belowground net primary production averaged 60% of TNPP on the two xeric sites and 42% of TNPP on the two mesic sites. This difference in production allocation between the two hygrotopes explains some of the between-site variation in foliage efficiency which was not accounted for by variation in foliage biomass. On the xeric sites, where moisture deficiencies appear to be limiting production, a multiple regression equation using foliage biomass, stand density, and stand age provided a better prediction of ANPP than did an equation which used foliage nitrogen content, stand density and stand age. Stand foliage biomass and stand density were significant variables in describing variation in foliage nitrogen efficiency (ANPP per kg of foliage nitrogen; an extension of the concept of "nitrogen productivity"). Either foliage efficiency or foliage nitrogen efficiency, in combination with data on the allocation of TNPP offer potentially useful alternatives to carbon budgets as driving functions for simulation models of forest production.
Forestry, Faculty of
Graduate

Both Pinus radiata and Chamaecytisus palmensis were inducted into tissue culture. In vitro clonal shoots were generated from cotyledon-derived meristematic cultures of P. radiata. Attempts were made to induce shoot organogenesis in C. palmensis explants, on solid media supplemented with a range of plant growth regulators. In vitro clonal shoots of C. palmensis were generated from seedling explants. The potential for Pb phytoextraction was investigated in seedlings and clones of P. radiata and C. palmensis. Aspects of tolerance, uptake, and translocation of Pb were studied within each species and in comparison to each other. Effects of Pb on different aspects of plant growth were examined including inhibition of seed germination, root growth inhibition, fresh weight changes of in vitro tissue, and responses of seedlings and excised shoots in solution culture. Both P. radiata and C. palmensis were insensitive to Pb during seed germination. Pb inhibited formation of lateral roots and inhibited root and shoot elongation in P. radiata seedlings. C. palmensis displayed greater tolerance to Pb than P. radiata during early seedling growth. Plants growing in hydroponic culture were exposed to Pb(N0₃)2, with and without the addition of the chelating agents H-EDTA and EDTA. Subsequently treated materials were examined for Pb uptake by flame atomic absorption spectrometry. Both P. radiata and C. palmensis accumulated unchelated Pb predominantly in root tissue, while Pb, in the presence of H-EDTA or EDTA, was taken up principally by the shoots in both species. With transmission electron microscopy, ultrastructural observations were carried out on ultra-thin sections, derived from tissues treated with Pb in the presence and absence of chelators, from both P. radiata and C. palmensis. In P. radiata, Pb was deposited in cell walls in root tissues; and in intercellular spaces in shoot tissues. In C. palmensis, Pb was found in cell walls, bacteroids and mitochondria in root nodule tissue; in middle lamellae and intercellular spaces in root tissues; and in chloroplasts, pit membranes, and plasmodesmata in shoot tissues. When acid phosphatase activity, in response to Pb exposure, was examined in both species, no substantial differences were found with regard to treatment but some evidence was found of differences in response among P. radiata clones. No new isozymes of acid phosphatase were found in C. palmensis in response to Pb but evidence was found that root isozyme activity increased in response to unchelated Pb.

Dans cette thèse sont montrés des développements de l'approximation de la phase aléatoire (RPA) dans le contexte de théories à séparation de portée. On présente des travaux sur le formalisme de la RPA en général, et en particulier sur le formalisme "matrice diélectrique" qui est exploré de manière systématique. On montre un résumé d'un travail sur les équations RPA dans le contexte d'orbitales localisées, notamment des développements des orbitales virtuelles localisées que sont les "orbitales oscillantes projetées" (POO). Un programme a été écrit pour calculer des fonctions telles que le trou de d'échange, la fonction de réponse, etc... sur des grilles de l'espace réel (grilles parallélépipédiques ou de type "DFT"). On montre certaines de ces visualisations. Dans l'espace réel, on expose une adaptation de l'approximation du dénominateur effectif (EED), développée originellement dans l'espace réciproque en physique du solide. Également, les gradients analytiques des énergies de corrélation RPA dans le contexte de la séparation de portée sont dérivés. Le formalisme développé ici à l'aide d'un lagrangien permet une dérivation tout-en-un des termes courte- et longue-portée qui émergent dans les expressions du gradient, et qui montrent un parallèle intéressant. Des applications sont montrées, telles que des optimisations de géométries aux niveaux RSH-dRPA-I et RSH-SOSEX d'un ensemble de 16 petites molécules, ou encore le calcul et la visualisation des densités corrélées au niveau RSH-dRPA-I
In this thesis are shown developments in the random phase approximation (RPA) in the context of range-separated theories. We present advances in the formalism of the RPA in general, and particularly in the "dielectric matrix" formulation of RPA, which is explored in details. We show a summary of a work on the RPA equations with localized orbitals, especially developments of the virtual localized orbitals that are the "projected oscillatory orbitals" (POO). A program has been written to calculate functions such as the exchange hole, the response function, etc... on real space grid (parallelepipedic or of the "DFT" type) ; some of those visualizations are shown here. In the real space, we offer an adaptation of the effective energy denominator approximation (EED), originally developed in the reciprocal space in solid physics. The analytical gradients of the RPA correlation energies in the context of range separation has been derived. The formalism developed here with a Lagrangian allows an all-in-one derivation of the short- and long-range terms that emerge in the expressions of the gradient. These terms show interesting parallels. Geometry optimizations at the RSH-dRPA-I and RSH-SOSEX levels on a set of 16 molecules are shown, as well as calculations and visualizations of correlated densities at the RSH-dRPA-I level

Actif de la fin des années 1930 jusqu'aux années 1980, Pierre Dufau (1908-1985) est, par l'importance quantitative de sa production bâtie, l'un des principaux acteurs de l'architecture française des Trente Glorieuses. Spécialisé dans la réalisation d'immeubles de bureaux, de bâtiments civils et d'équipements, il fait également oeuvre dans le domaine de l'urbanisme en concevant le plan de reconstruction d'Amiens puis en étant, trente ans plus tard, responsable du plan d'aménagement du Nouveau Créteil. Pierre Dufau est relativement peu présent dans l'historiographie de l'architecture contemporaine, au même titre que nombre d'architectes de sa génération, récipiendaires de la grande commande publique et souvent Prix de Rome. On s'interrogera sur la temporalité de sa réception critique à l'appui du dépouillement des archives de son agence, souvent inédites. Le détail de sa production révèle la complexité d'un parcours où, tant par stratégie commerciale que par conviction, l'architecte se convertit aux thèses modernistes après une jeunesse marquée par le respect des leçons du classicisme. Écrivain prolifique sans être théoricien ni enseignant, Pierre Dufau s'attachera dans ses mémoires, publiées à titre posthume, à donner un sens à un parcours professionnel donnant à voir en réduction les enjeux comme les impensés d'une époque. On proposera, dans cette thèse, de dépasser l'analyse plastique et technique des édifices pour étudier la rationalité de leurs circuits de production, et la cohérence des discours qui accompagnent une oeuvre jusqu'à présent essentiellement inscrite en creux dans l'histoire de l'art
Active from the late 1930s to the 1980s, Pierre Dufau (1908-1985) is one of the leading performers in the French architecture during the ‘Trente Glorieuses’ period, due to the quantitative importance of his built production. Specialized in office buildings, public buildings and facilities, he was also involved in the field of urban planning by designing the reconstruction plan of the city of Amiens, and thirty years later by being responsible for the conception of the ‘Nouveau Créteil’ masterplan, in Paris suburbs. Pierre Dufau is relatively unnoticed in the historiography of contemporary architecture, similarly to many architects of his generation, although recipients of public work orders, and most of the time recipients of the ‘Prix de Rome’. The details of his production reveal the complexity of a professional career where, motivated by both commercial strategy and conviction, the architect ultimately converted to modernist theses after a youth marked by respect for the lessons of classicism. As a prolific writer but without being a theorist nor a teacher, Pierre Dufau strived to give through his posthumous memoirs a meaning to his professional path. In this thesis, we propose to go beyond the plastic and technical analysis of the buildings to focus on the rationality of their production cycle and the coherence of the discourse that accompanies a work essentially unnoticed in the history of art so far. We also study the temporality of Dufau's critical reception with the support of the inventory of his office’s unpublished archives, most of the time original

An in-plane molecular beam apparatus, which has previously been used for high resolution spectroscopic experiments employing bolometric detection, is modified for the measurement of total differential scattering cross sections. The same method of detection is employed in the scattering experiments whilst translational characteristics of molecules within the primary and secondary beams are determined by means of time of flight techniques using mass spectrometric detection. The performance of the apparatus for scattering experiments is established by comparing results with previously reported scattering measurements for the He+Ar system. The molecular beam apparatus is used to obtain information sensitive enough for determining more accurately the potential surfaces of some important, weakly anisotropic, molecular interactions, namely He+HF, Ne+HF and CH₄+CH₄. These systems are of considerable theoretical interest and are of paramount importance with respect to the development of a universal potential model for anisotropic systems in general. Further fruitful theoretical effort is considered to be possible only with the aid of accurate scattering data. Previous experimental information for these systems is either non-existent or simply insufficient for the purposes of accurate determination of the potential surface. The data presented in this work provides enough detail for accurate prediction of the isotropic component of the potentials for each system studied.

The pure rotational spectra of several van der Waals dimers and trimers, namely Ar-Cl₂, Ne-Kr, Ne-Xe, Ar-Xe, Kr-Xe, Ne₂-Kr and Ne₂-Xe, as well as Ar₂-OCS and Ar₂-CO₂, have been investigated using a pulsed molecular beam cavity microwave Fourier transform spectrometer. Ar-Cl₂ has been found to have a T-shaped geometry dominated by pairwise additive forces, in contrast to the previously studied linear complex Ar-ClF. An effective van der Waals bond distance has been obtained, as well as an average vibrational angle for Cl₂. This study has not only confirmed the structure obtained from electronic spectroscopy, but has also provided a reliable estimate of the ³⁵Cl nuclear quadrupole coupling constant in the free chlorine molecule. In the microwave investigation of four mixed rare gas dimers, the newest available mixed rare gas pair potentials have been adjusted to obtain the equilibrium distances (re) between the rare gas atoms. The results have been compared with those obtained from isotopic data. It has been found that the present literature re values for these dimers had been underestimated in the order of 1~2%. The quadrupole coupling constants of ⁸³Kr and ¹³¹Xe have been determined for several different species containing these nuclei. The magnitudes of these constants are in the order of several hundreds of kHz, which are surprisingly large. The induced dipole moments are estimated to be in the order of 0.01 D. Transitions of four isotopomers of ²⁰Ne₂-Kr and of six isotopomers of ²⁰Ne₂-Xe, all with C₂v symmetry, as well as two mixed isotopomers of ²⁰Ne²²Ne-Kr, have been measured. A recent theoretical model derived for such floppy systems has been used to obtain structural parameters. The structures, harmonic force constants, ⁸³Kr and ¹³¹Xe nuclear quadrupole coupling constants and dipole moments have been compared with the corresponding parameters of the dimers. Possible nonpairwise additive contributions to these properties have been deduced from deviations of the experimental values from those obtained from corresponding dimers assuming pairwise additivity. The complexes Ar₂-OCS and Ar₂-CO₂ have been found to have distorted tetrahedral geometries (C₂ and C₂v symmetry, respectively), with the linear molecule lying in the symmetry plane. Harmonic force field analyses have been performed for Ar₂-OCS and Ar₂-CO₂. The structures and force constants obtained indicate a dominance of pairwise additivity. The basic geometric trend in Ar₂-molecule trimers is discussed.

Mon sujet de recherche en création est né d'une question demeurée sans réponse ; pourquoi Auschwitz ? À la suite de mes investigations, j'ai réalisé que ce n'est pas tant l'atrocité liée exclusivement au camp de la mort que j'interrogeais et tentais de comprendre, mais la déshumanisation de l'individu. Par déshumanisation j'entends dépersonnalisation. J'ai donc essayé de comprendre quels sont les dispositifs sociaux qui causent ce durcissement face à l'individu. Comment en arrive-t-on à départir une vie qui mérite d'être protégée, pleurée et une autre qui ne le mérite pas ? J'ai tenté de répondre à ma problématique de recherche initiale : «Comment redonner l'humanité aux individus par le biais de l'installation ?» en adoptant une perspective artistique. Dès le début de ma recherche, je me suis trouvée devant une impasse : les ouvrages théoriques sur le devoir de mémoire renvoient systématiquement aux guerres, aux génocides, à la « Grande Histoire », à la « Grande mémoire », celles des livres, alors que ce qui m'intéresse c'est la « petite mémoire ». Cette petite mémoire qui fait l'importance et l'unicité de chacun, cette masse de petites choses prônant notre différence les uns des autres. En m'inscrivant dans une démarche heuristique, j'ai démontré par un travail expérientiel, la pertinence de me concentrer sur la « petite mémoire » (Boltanski, 2002) et l'importance de commémorer l'unicité de chacun. À force d'expérimentations, une hypothèse de création a émergé et elle s'est déployée sous la forme de l'installation. J'ai donc délaissé la peinture et le dessin pour l'installation, dans le but d'offrir au spectateur une expérience de l'art différente de celle à laquelle je le conviais avant, dont l'oeuvre est étroitement liée au lieu d'exposition. Bien que le monument soit associé à la longévité, aux matériaux durables tels le marbre, la pierre, j'ai privilégié Fimpermanence pour mon oeuvre finale, car contrairement à la croyance répandue, les monuments de granit ne sont-ils pas conçus justement pour oublier, pour régler l'affaire une fois pour toute, alors qu'en utilisant des matériaux éphémères, nous serons obligés de nous rappeler ; il faudra refaire la prière, encore et encore, afin que la mémoire se perpétue. Pour la dernière étape de mon projet, j'ai fait une analyse dérivée de la phénoménologie structurale (Mucchielli, 1983). Cette méthode stipule que notre essence est, de façon spontanée et inconsciente, imprégnée dans chacun des gestes ayant transformé de façon intentionnelle la matière. C'est ainsi que j'ai pu saisir et cibler les intentions profondes de la communauté avec laquelle j'ai travaillé. Enfin, les principaux résultats de cette recherche en création ont culminé par la réalisation d'une d'installation in situ, qui s'est tenue dans le jardin du couvent de la Congrégation des Soeurs du Très Saint-Sacrement; le lieu étant inhérent à l'oeuvre, il était essentiel de réaliser l'exposition à cet endroit précis.

A country’s education system is a vital component of the country’s success. Without an excellent education system, our social, economic and financial positioning becomes threatened. At the heart of our education system lie our educators. Good educators are the key to an excellent education system. The loss of educators to the education system is significantly more than the current influx of qualified educators into schools. A great concern is why the South African education system is losing such large quantities of qualified and experienced educators. The literature review of this study focused on the factors contributing to job (dis)satisfaction and how it impacts on educators. Various sources were used to complete the literature study. The empirical study was done by means of quantitative research by distributing questionnaires to participating schools in the Vaal Triangle District. The educators at each of these schools were asked to complete a questionnaire that focussed on the issues that may contribute to job (dis)satisfaction and were divided into different sub-sections. The results were analysed and interpreted and certain recommendations were made in terms of the direct results and conclusions raised by the empirical study. The primary objective of this study was to determine the level of job satisfaction among some educators in the Vaal Triangle schools. The researcher looked at various trends in the education system and collected data relating to the determinants of job (dis)satisfaction in the school environment. The study showed that educators within the study population were not satisfied with their working conditions and should these issues be addressed by Department of Education, it could lead to fewer educators leaving the education system to seek work elsewhere.
MBA, North-West University, Potchefstroom Campus, 2014

碩士
國立中興大學
生命科學系
94
In order to elucidate some physiological characteristics of hemiphyte in response to water deficit, Ficus microcarpa was used as material. It was treated with natural water deficit as well as artificial osmostic stress. Results showed that the change of leaf water potential (Ψ) was not so large, but stomata resistant (Rs) increased suddenly with the degree of stress level in both natural drought and artificial osmostic stress. Suggesting in water deficit F. microcarpa could avoid water loss by closing stoma. It was also found that predawn Fv/Fm of epiphytic F. microcarpa was closely related to the minimum temperature of measured day, the photosynthetically active radiation (PAR) of one day before measurement and Rs. For the Fv/Fm measured at noon, it was affected by average temperature of measured day, Rs, and Ψ. Besides, when leaves were treated with 1500 μmol m-2 s-1 PAR for 2 hrs, their Fv/Fm decreased with Rs increasing, in spite of under osmostic stress or not; but this decreasing was drastic for detached leaves. In addition, under high illumination, detached leaves showed lower qf (include qE and qT, two of NPQ relaxing within seconds to tens of minutes) than attached leaves, in spite of high NPQ in detached leaves; probably detached leaves could not protected their PSII by ABA from roots. Present study also used scotch tape to limit the diffusing of CO2 from atmosphere to leaves. The results indicated that stomata closing itself did not affect the efficiency of PSII. Therefore, the decreasing of PSII efficiency in osmotic stressed leaves was due to the other effects. In contrast to the F. microcarpa avoiding water loss by closing stoma, present study also found that Ψ of a phreatophyte-Salix warburgii decreased drastically under osmotic stress due to the insensitive stoma appearture.

碩士
國立臺灣大學
園藝學研究所
84
The potential use of vesicular-arbuscular mycorrhiza fungi (VAMF) in the plug system of ornamental plants was intensively studied. Nine ornamental plants inculding five kinds of seedlings, such as scarlet sage ,polyanthus, ageratum, cineraria, dahlia and four kinds of cuttings, such as star-cluster, common lantana, wedelia anf cigar flower. The plant materials were inoculated with VAMF (inoculum content hyphae, spores, root and sand) in the mixture of perlite, vermiculite and peat growth medium during seed sowing or cutting in plug. The best inoculum, inoculum intensity, phosphorous application, growth medium and temperature for mycorrhizal cineraria and dahlia seedlings was recommended, the others also could result in better plant growth and higher mycorrhizal infection percentage in plug sysytem. Plants inoculated with VAMF grown in different temperature, growth medium and phosphorous application in 4-inch pot resulted that the benefits of mycorrhizal associations were affected by the specific combinations between VAMF and plants and environment factors. The better choice of inoculums are G.mix (Mixture of Glomus etunicatum, Glomus mosseae and G. fasciculatum) or Glomus etunicatum. The specific combinations of VAMF-plants were listed:(1)scarlet sage:G.mix or G. etunicatum;(2)polyanthus: G.mix;(3)ageratum:G.mix;(4)wedelia:G.etunicatum;(5)star-cluster :G.mix;(6)cigar flower:G.mix or Gig. gigantea;(7)common lantana:G.etunicatum;(8)dahlia:G.fasciculatum or G.etunicatum; (9)cineraria:G.mix..

The seed storage fungi (xerotolerant) species of the genera Aspergillus and Penicillium} are renowned for their devastating effects on stored grain and grain products. In view of the fact that most of these fungi Iiberate toxins which can be harmful to both man and his livestock this problem is becoming increasingly relevant, particularly in developing countries. The seed storage fungi are said to be saprophytes and opportunistic invaders of dead or naturally dried organic matter, and as such no direct host-pathogen relationship has been ascribed to them. This dissertation reports aspects of an investigation into the modes/pathways utilised by these fungi in their infection of maize caryopses (seeds) and plants. The work involved studies on: the effects of protracted storage on maize seeds; the morphology of storage fungi; extra-cellular enzymes of storage fungi; the pathways utiIised by the storage fungi in invasion of seed tissues; and the effects of the storage fungi on the seeds. Correlations have been made on a species basis between the extent of seed deterioration and fungal aggressiveness. The results of these investigations indicated that apart from affecting seed vigour and viability, these fungi can also affect plant vigour. This latter aspect was further investigated to determine whether a seed storage fungus could infect germinating maize seeds, and remain an internal contaminant of the tissues during plant growth and development. These latter studies revealed that Aspergillus flavus var. columnaris is capable of systemic transmission from one seed generation to the next. This hitherto unrecognised phenomenon apart from indicating that the fungal species is in fact a biotroph as well as a saprophyte, also has implications In control measures.
Thesis (Ph.D.)-University of Natal, Durban, 1990.

This thesis examines ways in which identities have been represented in new South African play texts. It begins by exploring various ways in which identity has been described from various philosophical, psychological and anthropological perspectives. In particular, the thesis describes its methodology in terms of Gilles Deleuze's definition of "rhizomatic" structures. The introduction also elaborates ways in which drama is uniquely suited to represent ¨C as well as to effect ¨C transformations of identity. The thesis then moves on to an examination of specific texts in terms of four broad areas of investigation ¨C gender, political affiliation, ethnicity and syncretism. In these chapters a number of play texts are investigated from different points of view. Firstly, in a chapter on gender, the thesis focuses specifically on issues of masculinity and exile in plays by Athol Fugard, Anthony Akerman and Zakes Mda. This chapter explores orientations of the masculine which have become embedded within notions of nationalism and patriotism. In terms of political affiliations, the thesis looks at what Loren Kruger has called "post-anti-apartheid theatre" (2002: 233) and considers the trend away from protest theatre. With reference to the plays of Mike van Graan it also examines new forms of protest theatre. This chapter also explores plays which were inspired by the Truth and Reconciliation Commission (TRC) and looks in more detail at Ubu and the Truth Commission by Jane Taylor. When considering ethnicities, the thesis reflects on how identity in terms of an ethnic collective is most often premised on laws of exclusion, and on the construction of what Benedict Anderson refers to as an "imagined community" (1991: 15). Representations of ethnic identities are then analysed in Happy Natives by Greig Coetzee. Syncretism seems to present a preferable description of how South African identities can be constructed and the thesis then elaborates attempts to forge a new identity in terms of amalgamation and a creative fusion of cultural resources, with particular reference to the plays of Brett Bailey and Reza de Wet. In the conclusion of this thesis, the thorny issue of racial identities is considered, and in particular the trope of the "rainbow nation", which many writers regard as a problematic blanketing description which cancels out difference. Instead, Ashraf Jamal's "radical syncretism", which does not seek to subsume heterogeneous identities, is suggested as a viable means of approaching definitions of identity. The final chapter also briefly touches on the development of physical theatre in South Africa and describes how the body can be used as a tool for transformation, relying principally on the writings of Mark Fleishman and Eugenio Barba in this regard. Finally, again resorting to a Deleuzian vocabulary which describes identity as constructed in terms of lines operating on particular planes, the thesis considers whether it may not be more beneficial in the post-apartheid context to favour paradoxical processes which relinquish identities, instead of those which attempt to consolidate them. @ 2008 Author Please cite as follows: Krueger, AR 2008, Experiments in freedom : representations of identity in new South African drama : an investigation into identity formations in some post-apartheid play-texts published in English by South African writers, from 1994 - 2007, DLitt thesis, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-10282008-141823/ > D497/gm
Thesis (DLitt)--University of Pretoria, 2008.
English
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