In this work the dynamics of permalloy circular magnetic islands of 225 nm radius and 10 nm thickness arranged into square lattices was investigated employing micromagnetic simulations.The simulations of the vortex magnetization loops and the ferromagnetic resonance (FMR) spectra were carried out using a free micromagnetics simulation software Mumax3. The obtained data was analyzed using Matlab. The simulations were carried out on a single vortex island as well as on two different lattices. The first lattice is comprised of interacting islands, while the second lattice - of non-interacting islands, separated by 25 nm and by 450 nm edge-to-edge distance, respectively. The magnetization loops were simulated by applying the static magnetic field in-plane of the single island or the lattice. The FMR simulations were carried out by applying the static magnetic field in-plane of the lattice and after the system reached the ground state in that field, the excitation as a sinc pulse was sent out along the out-of-plane direction of the lattice. The analysis of the obtained FMR spectra revealed that the several resonant modes are present for the single vortex island and the lattice, comprised of such islands. However, the physical explanation of the origin of those modes is a subject for further investigations.

Thesis (PhD)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Climate sets range limits in many taxa, and as climate changes, the ranges that plants and animals occupy are altered. The responses of species to climate change involve either migration or local adaptation. An investigation of the local physiological adaptation shown by indigenous and alien arthropods to temperature acclimation formed the primary focus of this study. Increased environmental temperatures favour the establishment of alien species on Southern Ocean Islands. The first records of Porce/lio scaber Latreille, 1804 (Isopoda, Porcellionidae) and an Aphidius wasp species from Marion Island were documented here. The alien wasp was discovered in 2003 and had a current known distribution along the east coast of Marion Island. Both isopods and wasps were reproducing successfully on Marion Island. The wasp species is an aphid parasitoid and had been found mummifying the alien aphid Rhopalosiphum padi. These introductions highlighted the ongoing conflict between use and conservation on the Southern Ocean Islands. Despite considerable work on the upper and lower lethal limits of insects, several major taxa have received little attention. Here this issue was addressed and the lower and upper thermal tolerances and cold hardiness strategy of Antarciopsocus jeanneli Badonnel (Psocoptera: Elipsocidae) from sub-Antarctic Marion Island was investigated. A. jeanneli is freeze intolerant, and more specifically, moderately chill tolerant. Field fresh A. jeanne li had a mean supercooling point (SCP) of -11.1oC, whereas LTSO was -7.7°C, indicating pre-freeze mortality. A. jeanneli responded to acclimation: mean SCP increased from -IS.8°C at a treatment temperature ofO°C, to -7.3°C at ISOC. Investigations of the responses to acclimation of upper and lower lethal limits and limits to activity in insects have focussed primarily on Drosophila. Halmaeusa atriceps (Staphylinidae) was examined for thermal tolerance responses to acclimation, and seasonal acclimatization. In summer and winter, lower lethal temperatures of adults and larvae were c. -7.6 ± 0.03 and -11.1 ± 0.06 °C, respectively. Supercooling points (SCPs) were more variable, with winter SCPs of -S.4 ± 0.4 °C in larvae and -6.3 ± 0.8 °C in adults. The species appeared to be chill susceptible in summer and moderately freeze tolerant in winter, thus showing seasonal acclimatization. Critical thermal minima varied between -3.6 ± 0.2 and -0.6 ± 0.2 °C in larvae, and from -4.1 ± 0.1 to -0.8 ± 0.2 °C in adults. These findings were in keeping with the general pattern found in insects, although this species differed in several respects from others found on Marion Island. In this study the differential responses of indigenous and invasive springtails to temperature were explicitly examined in the context of the beneficial acclimation hypothesis (BAH) and its alternatives. In particular, the thermal acclimation responses of desiccation resistance, supercooling ability, lower and upper thermal limits were compared. Invasive springtails (Pogonognathellus jlavescens, Isotomurus palustris and Ceratophysella denticulata) did not display greater phenotypic flexibility than indigenous springtails (Cryptopygus antarcticus and Tullbergia bisetosa), but did perform better under high temperature conditions. Indigenous species, however, performed better under low temperature conditions. In most cases the BAH was not supported, or could not be distinguished from its alternatives. The prediction that invasive species will outperform indigenous species as climates on Southern Ocean Islands warm was supported. Because temperature plays such a large role in the distribution, abundance and physiological tolerances of invertebrates, microhabitat temperatures along an altitudinal gradient (0 to 800 m above sea level (asi)) were investigated over a two-year period on Marion Island. Mean microhabitat temperatures were comparable to those from previous studies for Southern Ocean Islands, and declined with increasing altitude. The 800 m asl site had the most severe microclimate (highest absolute maximum, lowest absolute minimum and the highest frequency of freeze-thaw cycles). Year one was substantially colder than year two, indicating that interannual variation in microclimate conditions could be responsible for substantial mortality amongst. invertebrate populations. Indeed, indigenous species were best able to tolerate the high incidence of low temperatures at high altitudes, whereas alien species appeared to be confined to lower altitudinal sites on Marion Island, possibly as a consequence of extreme low temperatures at higher altitudes. / AFRIKAANSE OPSOMMING: Klimaat is een van die grootste faktore wat die verpreiding en digthede van dier en plantspesies bepaal. Soos wat klimaatsverandering plaasvind, kan spesies migreer om stresvolle klimaatstoestande te vermy, of hulle kan aanpas by plaaslike omstandighede. Dit is die laasgenoemde opsie wat in hierdie tesis ondersoek was. Die opsporing van Porcellio scaber Latreille, 1804 (Isopoda Porcellionidae) en 'n Aphidius wesp van Marion Eiland word hier aangeteken. Die huidige verspreiding van houtluise in die omgewing van die Navorsingstasie dui daarop dat hulle die eiland waarskynlik vanaf Kaapstad in bou-materiaal bereik het. Die wesp is gedurende 2003 ontdek en is tans versprei langs die oostelike kuslyn van Marion Eiland. Beide hierdie spesies plant suksesvol voort op Marion Eiland. Die wesp spesie parasiteer die uitheemse plantluis Rhopalosiphum padi. Uitheemse muise en die inheemse kleinskedebek weier tot dusver om P. scaber te eet. Die ontdekking van twee nuwe uitheemse spesies dui weereens op die konflik tussen bewaring en benutting van die Suidsee Eilande. Ten spyte daarvan dat aansienlike aandag gewy is aan die hoë- en lae temperatuur toleransies van insekte, is daar talle taksa wat selde nagevors word. Dié toleransies is dus nagevors vir die boekluis Antarctopsocus jeanneli Badennel (Psocoptera: Elipsocidae) van Marion Eiland. Die spesie is vries vermydend, en meer spesifiek, matig verkoelingsbestand. Veldvars A. jeanneli het 'n gemiddelde superverkoelingspunt van - 11.1 °C gehad, en letale temperature (LTSO) van -7.7 °C, wat aandui dat individue vrek voordat hulle vnes, Hierdie spesie reageer op akklimasie: gemiddelde superverkoelingspunt het toegeneem van -15.8 °C na akklimasie by 0 °C tot -7.3 °C na akklimasie by 15 oe. Die effek van akklimasie op temperatuur toleransie in insekte het dusver meestalop Drosophila gefokus. Hier vors ons die effek van akklimasie op die temperatuur toleransie van Halmaeusa atriceps (Styphylynidae) na. In die somer en winter was die lae letale temperature van kewers en larwes onderskeidelik -7.6 ± 0.03 en -11.1 ± 0.06 °C. Superverkoelingspunte (SVP) het meer gevarieer, met SVP van -5.4 ± 0.4 °C in larwes en -6.3 ± 0.8 oe in kewers. Die spesie IS verkoelingsvatbaar in die somer en matig vriesbestand in die winter, wat dui op akklimatisasie in hierdie spesie. Kritiese termale minima het tussen -3.6 ± 0.2 en -0.6 ± 0.2 oe in larwes, en tussen -4.1 ± 0.1 tot -0.8 ± 0.2 oe in kewers gewissel. Hierdie spesie blyk dieselfde fisiologiese tendense wat in insekte te vinde is uit te beeld, maar verskil in verskeie opsigte van ander insekte op Marion Eiland. Hierdie studie het ook die verskillende reaksies van inheemse en uitheemse springsterte met betrekking tot temperatuur akklimasie bestudeer. Die voordelige-akklimasie hipotese en sy alternatiewe hipoteses is in terme van akklimasiereaksies tot desikkasie weerstand, superverkoeling en lae- en hoë temperatuur bestandheid in Marion Eiland springsterte getoets. Die uitheemse springsterte (Pogonognathellus jlavescens, Isotomurus cf palustris en Ceratophysella denticulata) het nie beter fenotipiese plastisiteit getoon as die inheemse spesies (Cryptopygus antarcticus en Tullbergia bisetosa) nie. Die inheemse spesies het egter beter gevaar onder lae-temperatuur toestande. Die voordeligeakklimasie hipotese ontvang nie veelondersteuning in die huidige studie nie, maar kon in sommige gevalle nie van die alternatiewe hipoteses onderskei word nie. Klimaatsverandering mag uitheemse spesies bevoordeel. Die rol wat temperatuur in die verspreiding en fisiologiese toleransies van invertebrate speel word lank reeds waardeer. Daarom vors hierdie studie die mikrohabitat temperature teen 'n gradient tussen seespieël en 800 m bo seespieël (m bs) oor 'n tydperk van twee jaar op Marion Eiland na. Gemiddelde temperature is vergelykbaar met die van vorige studies op Marion Eiland, en neem af soos wat hoogte bo seespieël toeneem. Die 800 m bs studie-gebied het die mees stresvolle mikrohabitat-toestande ondervind (die hoogste absolute maksimum, laagste absolute minimum temperature, en die meeste vries-ontdooi siklusse). Inheemse spesies op Marion Eiland toon hoër.toleransies tot lae temperature as uiheemse spesies, laasgenoemde kom slegs voor by laer hoogtes bo seespieël, waar ekstreme ternperatuur-toestande dalk minder volop is. Klimaatsverwarming mag egter tot 'n toename in ekstreme weerstoestande lei op Marion Eiland, wat aansienlike mortaliteit in invertebraat populasies kan veroorsaak.

Engineers Without Borders New Zealand (EWBNZ) has recently reached a stage in its organisational growth where a new strategy is needed to ensure its future engineering development initiatives are more consistent with its guiding philosophy of delivering sustainable long term development projects. A quantitative and qualitative analysis of the perceptions of the committee tasked with delivering projects revealed a preference for a strategy which enabled ‘placement’ type projects. To develop this strategy a qualitative analysis was conducted which focused on ascertaining what strategies and organisational structures are employed by comparable EWB organisations to deliver development projects. This process revealed EWB Australia to have a placement project process model which was deemed as the most acceptable to replicate. An implementation strategy and supporting set of recommendations were provided for this new placement project strategy. The most significant recommendation given to support this new strategy was to concentrate EWBNZ’s resources by prioritising projects in only two of the four countries EWBNZ currently operates. The countries deemed a strategic priority were Samoa and Tonga.

The novels of George Mackay Brown have often been read as upholding a traditional ideal of community as that which is singular and complete, a community which exists outside time and history. As this thesis will show, however, Brown emphasises themes of community, history and myth in his work not in order to validate them without reservation, but to question what use these ideas may have in contemporary life. By reading his novels in conjunction with the work of continental theorists ranging from Martin Heidegger to Jean-Luc Nancy, it becomes apparent that Brown critically explores a post-Kantian modernity in which metaphysical or faith-based foundations are no longer possible. Brown's greatest theme throughout his work is not only how community is built and maintained, but also how it is destroyed, and what life remains after that destruction. Brown continually problematises the idea of community in order to show both its relevance and impossibility in modern society. In separately regarding each of Brown's novels in length, this thesis will highlight the various approaches Brown takes to community: the potentially romantic view of community in Beside the Ocean of time; the centrality of sacrifice for the establishing of community in Magnus; and the interections between community and history in Time in a Red Coat, and Vinland. The thesis then turns directly to the question of the relation between individuals and community in Greenvoe, and ends with a discussion of the way in which Brown portrays his own relation to community in his nonfiction and autobiographical writings. Throughout the thesis, the prevailing notion of Brown as a parochial or naive writer will be continually questioned. In addition, by integrating a wide variety of continental theorists into a discussion of Brown's work, this thesis will explore new opportunities for the general study of contemporary Scottish fiction. By revealing Brown to be a more nuanced thinker of the relation between modernity and community than previous critics have allowed, this thesis will both offer a new perspective on Brown's novels and open new paths for the discussion of the role of community in modern literature.

The small land area of the islands of the Maldives, combined with high population density, makes the communities of these islands vulnerable to natural disaster events such as flooding and tsunami. The Indian Ocean Tsunami on 26 December 2004 impacted 69 islands of the Maldives, killing 82 people, leaving 26 people missing and 15, 000 people internally displaced, making it the worst disaster in recorded history. Following the event, the Government of the Maldives announced a Safer Island Development Programme which seeks to provide the infrastructure necessary to adapt to natural disasters. The key focus of disaster management is to reduce the vulnerability of the communities exposed to hazards and risks, and to help them to enhance their resilience. Efforts have been made to develop safer and sustainable communities in all corners of the developed and developing worlds. New Zealand Government announced its effort to build safe and secure communities in 2007 while at a local level the Christchurch City Council published the Safer Christchurch Strategy in 2005. Overseas, the Community Strategy 2000, outlines the vision of "A safe and strong Island" at Isle of Wight United Kingdom. The islands of the Maldives have natural characteristics which make them vulnerable to disasters such as tsunami. This research has been able to identify the relationship between these characteristics and the natural vulnerability of the islands using the data that was collected following the Indian Ocean Tsunami. Out of 11 island, that have been identified for the Safer Islands Development Programme, one island is found to have very high natural vulnerability and 5 islands a high natural vulnerability, from the island vulnerability index model developed through this study. The Island Vulnerability Index model could be used to enhance the present Safer Island Development Programme island selection criteria, to reduce the possibility of 'building risk' into the infrastructure development on the islands. The index could also be used in the Environmental Impact Assessment studies to address the issue of disasters, effective resources allocation in the Public Sector Infrastructure Programme for 'building back better', and resource identification in land use planning.

No description available.

In 2004, the Institut f??r Deutsche Sprache published the neologism dictionary "Neuer Wortschatz: Neologismen der 90er Jahre im Deutschen", which contains new words that entered the German language during the 1990s (for example "Elchtest" and "Handy"). Based on this dictionary this master's thesis examines to what extent those new words have reached the vocabulary of German speakers in the German language island of Kitchener-Waterloo, Ontario. Moreover, it describes the attitudes of the local speakers of German towards these new words. <br /><br /> First, the term <em>neologism</em> is defined, different types of neologisms are presented and a review of research on German neologisms in general is given. Second, the historical background of the German speakers in Kitchener-Waterloo is described. The focal point of this thesis, however, is on the methodology of the study and on the results of the actual research coming from a data collection amongst German speakers of Kitchener-Waterloo. On the one hand, the focus of the analysis is on the question to what extent this language change in the German language in Europe has reached them. Hence knowledge and usage of the neologisms are examined. On the other hand, the focus is on the attitudes the interviewees have towards these new words. Both aspects are compared to the result of the same study administered to German speakers, who lived during the 1990s in Germany. Hence knowledge and attitudes of the Canadian German speakers can be compared to those of speakers in Germany. <br /><br /> The results show that the participants from Germany knew more neologisms than those from Kitchener Waterloo. Concerning attitudes, both groups showed a slightly positive attitude towards the neologisms with interesting differences regarding certain types of neologisms.

Escherichia coli (E. coli) are a diverse species of bacteria that reside, often harmoniously and beneficially, in the gastrointestinal tracts of humans and other mammals. However, some strains are associated with serious intestinal and extra-intestinal disease and are considered pathogens. The main differences between strains of these different E. coli pathotypes can be explained by the acquisition of genetic information introduced by mobile genetic elements, in particular bacteriophage. In enterohaemorrhagic E. coli (EHEC) O157:H7 strain EDL933, a pathotype of E. coli containing prophage-encoded Shiga toxins associated with severe gastrointestinal and systemic disease in humans, these horizontally acquired elements have been termed O-islands (OIs) and include both fully functional and cryptic prophages. The overall aim of this research was to try and determine what these OIs are actually doing for the bacteria. Systems pertinent in the life cycle and virulence of this pathogen were therefore investigated by phenotypically screening a large library of OI deletions in EHEC strain TUV93-0, a Shiga toxin-negative derivative strain of EDL933, and then comparing these with the parent strain. These analyses highlighted a subset of OIs with the potential to regulate motility and type III secretion (T3S), the latter being an essential colonisation factor for EHEC that is encoded by the locus of enterocyte effacement (LEE). Deletion of OI-51, a 14.93 Kb cryptic prophage designated as CP-933C, significantly reduced persistence of faecal shedding in sheep and levels of T3S expression in vitro. Cloning and complementation together with targeted allelic replacements in OI-51 identified a novel positive regulator of the LEE, encoded by ecs1581 in the sequenced E. coli O157:H7 strain Sakai that is present but not annotated in the EDL933 sequence. Functionally important residues of ECs1581 were identified by site-directed mutagenesis based on phenotypic variants present in strains from different E. coli pathotypes, including strains not harbouring a LEE-encoded T3S system. This regulator was subsequently termed RgdR based on a motif demonstrated to be important for stimulation of gene expression from LEE1. Purified RgdR protein was able to form multiple complexes on a PCR generated LEE1 promoter fragment, and activation of this operon appeared to require this DNA binding capacity as a non-T3S inducing variant was unable to bind this same LEE1 promoter fragment. RgdR did not directly activate LEE1 transcription in vitro, nor did it activate transcription by relieving H-NS repression as proposed for the global regulator Ler (LEE-encoded regulator). However, RgdR activation did require a wild type LEE1 promoter and the Ler auto-induction cycle to induce LEE2-5 expression and T3S. RgdR was able to increase binding to Congo red and was capable of repressing bacterial motility. Further analyses demonstrated that RgdR did not regulate T3S and cell motility via GrlA (global regulator of LEE activator) and QseC (quorum sensing E. coli regulator C), two established regulators in E. coli that control LEE gene expression and motility in conjunction with their partners, GrlR (global regulator of LEE repressor) and QseB (quorum sensing E. coli regulator B) respectively. RgdR is therefore identified as a novel regulator able to co-ordinate T3S and motility expression. This research has identified OI-51 as being important for EHEC O157:H7 colonisation in sheep and has identified a completely new family of small bacterial regulators that control surface factor expression in E. coli.

Two major problems preventing the clinical application of pancreatic islet transplantation were investigated. The problem of allograft rejection was studied in rats, made diabetic by streptozotocin treatment. It was shown that DA rats given LEW renal allografts and treated with cyclosporine accepted their grafts, and subsequently developed a strain-specific unresponsive state that allowed successful transplantation of LEW islets without further immunosuppression, whilst BN islets were rejected normally. The effect was demonstrated to be independent of the site of islet transplantation, and, once an islet allograft had been accepted, it was possible to remove the original renal allograft without affecting the transplanted islets. The effect was shown to apply to another strain combination (LEW into PVG), and also to animals made unresponsive to renal allografts by another method (donor-specific blood transfusion). The problem of separation of adequate numbers of viable islets from the pancreas was studied in the rat, dog, pig and human. To aid the investigation, supravital staining techniques were developed, using neutral red to identify the islets, and fluorescein diacetate and ethidium bromide to assess islet viability. A variety of islet isolation techniques were investigated, and a new technique for isolation of islets from the dog pancreas, yielding up to 160,000 islets from 1 pancreas with a maximum purity of 80%, was developed. The structural integrity and in vitro function of the isolated islets was demonstrated, but it was not possible to prevent diabetes by autotransplantation of islets to the portal vein of pancreatectomised dogs. A method for isolation of islets from the human pancreas was developed from that used in the dog, yielding up to 80,000 islets from a whole pancreas, with a maximum purity of 40%. The technique was shown to be both simple and reliable. The structural integrity and in vitro function of the isolated islets was demonstrated, and the viability of the islets proven by successful transplantation under the kidney capsule of nude mice.

Acquisition of a superantigen pathogenicity island (SaPI) significantly increases virulence in Staphylococcus aureus. Horizontal transfer of SaPIs occurs at high frequency and depends upon a helper bacteriophage, either through direct infection or SOS-mediated induction of a lysogen. SaPIs hijack the packaging machinery of the helper phage, leading to the formation of SaPI-containing transducing particles that can introduce the pathogenicity island into neighboring SaPI-negative cells. All SaPIs contain a conserved core of genes, some of which are co-transcribed as an operon and encode functions involved in helper exploitation. The goal of this study was to more fully understand the intricate relationships between the SaPI elements and their helper bacteriophages, specifically any regulatory crosstalk that might occur between them. We demonstrated phage-host interactions in 80 and 80α, and SaPI1 and SaPIbov1-mediated crosstalk with helper phage 80α. The phage Sri protein was shown to be a bi-functional protein that both derepresses SaPI1 and interferes with host chromosome replication. Incoming SaPI1 experiments showed that SaPI1 modulates the levels of the N-terminal part of orf14 mRNA. Induction experiments using the 80α ΔrinA phage as a genetic tool, reveal several new phage genes that SaPI1 targets for expression modulation. Finally, a novel SaPI1 interference mechanism was identified. In an 80α ΔrinA mutant, which cannot activate its late operon, SaPI1 can directly turn on expression of the packaging and structural genes in a noncanonical manner, initiating from the 2nd gene in the operon, the large terminase subunit.