Com o advento dos estudos moleculares evolutivos baseados nas sequências dos genes de RNAr 16S em cianobactérias, a taxonomia de Anabaena (Cyanobacteria) tem sido amplamente discutida e uma revisão deste gênero faz-se necessária. Os problemas variam desde o nível genérico, tal como o grupo Anabaena Aphanizomenon, até níveis de diferenciação de linhagens (morfoespécies). Estudos moleculares de linhagens de Anabaena isoladas de ecossistemas brasileiros são inexistentes. A fim de se explorar a diversidade, filogenia e diversificação evolutiva de Anabaena isoladas de ambientes brasileiros, estudos fenotípicos e genotípicos foram realizados no presente estudo. Um total de 43 isolados foram obtidos de corpos d´água do Estado de São Paulo (Reservatórios Billings, Santo Grande, Rio Piracicaba e Lago da ESALQ/USP (Engenharia) e do Estado do Ceará (Lagoa do Povoado Nova Aurora e Rio Camarão). As espécies de Anabaena isoladas foram identificadas como A. aphanizomenoides Forti, A. circinalis Rabenhorst ex Bornet et Flahault, A. crassa (Lemmermann) Komárková-Legnerová et Cronberg, A. cf. fallax Komárek et Komárková-Legnerová e A. planctonica Brunnthaler. Os meios de cultura usados no isolamento das cianobactérias foram AA/4, ASM-1 e BGN, este último também nas variantes com 50% de NaNO3 (BG50) e sem nitrato (BGS), com ou sem adição de vitamina B12. O meio ASM-1 não promoveu o crescimento de Anabaena. As espécies A. circinalis e A. crassa não cresceram no meio de culturaBGN com 17,65 mM de NaNO3, apresentando crescimento no meio BG50. A adição de vitamina B12 favoreceu o crescimento de A. circinalis. Os caracteres morfológicos analisados para 23 isolados foram o comprimento (compr) e diâmetro (diam) da célula vegetativa (V), heterócito (HT), acineto (AC), espira (ES), razões (R) comprimento/diâmetro para V, HT e AC e razão diâmetro/comprimento para ES (RES). O diâmetro da bainha (diamBA) foi também avaliado. As análises de componentes principais (ACP) confirmaram que a espira é uma característica importante para separar as morfoespécies A. circinalis, A.crassa e A. cf. fallax. RV e RHT foram diacríticos para diferenciação de A. cf. fallax. O comprimento do acineto (comprAC) foi importante para diferenciar A. aphanizomenoides de A. planctonica. A bainha diferenciou A. crassa das outras morfoespécies. As análises filogenéticas para o RNAr 16S mostraram os isolados brasileiros de A. circinalis, A. crassa, A. planctonica, A. aphanizomenoides e A. cf. fallax em agrupamentos separados, confirmando os resultados dos caracteres morfológicos. Com exceção da A. planctonica, as sequências de RNAr 16S dos isolados brasileiros não agruparam com linhagens relativas provenientes de outros países, indicando que elas são únicas. As análises filogenéticas dos genes RNAr 16S, rpoC1, rbcL, tufA concatenados corroboraram os resultados de filogenia do gene de RNAr 16S e as identificações morfológicas. A tentativa de obtenção de padrões moleculares para as espécies de Anabaena isoladas do Brasil foi feita utilizando a técnica de PCR-DGGE. Os fragmentos da região 359-781 do RNAr 16S apresentaram banda única para A. circinalis, enquanto que mais de uma banda foi verificado nas outras morfoespécies de Anabaena. / The advent of molecular evolutionary studies based on 16S rRNA genes sequences of cyanobacteria, the taxonomy of Anabaena (Cyanobacteria) has been widely discussed and a revision of the genus is required. The problems range from the generic level, such as Anabaena Aphanizomenon group, to levels of strains differentiation (morphospecies). Molecular studies of Anabaena strains isolated from Brazilian ecosystems are lacking. In order to explore the diversity, phylogeny and evolutionary diversification of Anabaena strains isolated from Brazilian environments, phenotypic and genotypic studies were performed. A total of 43 Anabaena isolates were obtained from water bodies of Sao Paulo State (Billings reservoir, Santo Grande reservoir, Piracicaba river and Engenharia pond Esalq) and Ceara State (Povoado Nova Aurora pond and Camarao river). The isolated Anabaena species were identified as A. aphanizomenoides Forti, A. circinalis Rabenhorst ex Bornet et Flahault, A. crassa (Lemmermann) Komárková-Legnerová et Cronberg, A. cf. fallax Lomárek et Komárková-Legnerová and A. planctonica Brunnthaler. The culture media used for cyanobacterial isolation were AA/4, ASM-1 andBGN, the latter also in the variants with NaNO3 50% (BG50) and without nitrate (BGS), with and without addition of B12 vitamin. The ASM-1 medium did not promote the growth of Anabaena. The A. circinalis and A. crassa species had not grown inBGN culture medium with NaNO3 17.65 mM, showing growth in BG50 medium. The addition of B12 vitamin favored the growth of A. circinalis. The morphological characters analyzed for 23 isolates were the length (L) and diameter (D) of vegetative cell (V), heterocyte (HT), akinete (AK), coil (CO), L/D ratio (R) for V, HT and AK, and D/L ratio for CO (RCO). The sheath diameter (SD) was also evaluated. The principal component analysis (PCA) confirmed that the coil is an important feature to separate the morphospecies A. circinalis, A.crassa and A. cf. fallax. RV and RHT were diacritical for differentiation of A. cf. fallax. The akinete length (LAK) was important to differentiate A. aphanizomenoides from A. planctonica. The sheath differentiated A. crassa from other morphospecies. Phylogenetic analyses of 16S rRNA gene placed A. circinalis and A. crassa, A. planctonica, A. aphanizomenoides and A. cf. fallax Brazilian isolates in separated clades in agreement with morphological characters. With the exception of A. planctonica, the 16S rRNA sequences of the Brazilian isolates did not cluster with relative strains originated from other countries, indicating that they are unique. The phylogenetic analysis of concatenated genes16S rRNA, rpoC1, rbcL, tufA corroborated results of 16S rRNA phylogeny and morphological identifications. The attempt to obtain molecular standards for the Anabaena species isolated from Brazil was made using the PCR-DGGE technique. The fragments of the 359-781 region of 16S rRNA showed only one DNA band for A. circinalis, while more than one band was observed in other Anabaena morphospecies.

Η θεωρία σκέδασης καλύπτει ένα μεγάλο φάσμα επιστημονικών και τεχνολογικών εφαρμογών, όπως μη καταστρεπτικός έλεγχος, ραντάρ, σόναρ, γεωφυσική έρευνα, απομακρυσμένη καταγραφή, ιατρική απεικόνιση, υποθαλάσσια ακουστική, σεισμολογία, αναγνώριση βιολογικών προτύπων και ειδικές τεχνικές που εφαρμόζονται στη διαγνωστική ιατρική. Στις περισσότερες από τις παραπάνω περιπτώσεις η υπόθεση πως το υλικό είναι ισότροπο δεν αρκεί και προκειμένου τα αποτελέσματα να προσεγγίζουν ικανοποιητικά την πραγματικότητα, θα πρέπει να γίνει η παραδοχή πως ο χώρος είναι ανισότροπος, πως οι ιδιότητές του εξαρτώνται δηλαδή από την κατεύθυνση. Παρόλο που η ιδιότητα της ανισοτροπίας ήταν ήδη γνωστή από την εποχή του Green (μέσα 19ου αιώνα), λόγω της αυξημένης μαθηματικής πολυπλοκότητας που παρουσιάζει, μόνο τα τελευταία χρόνια εμφανίζεται σημαντικός αριθμός δημοσιεύσεων που ασχολούνται με την ανισότροπη σκέδαση, οι οποίες στην πλειοψηφία τους αναφέρονται μόνο σε ανισότροπο σκεδαστή. Η παρούσα διατριβή ερευνά το πρόβλημα ανισότροπης σκέδασης βαθμωτών πεδίων για τη γενική περίπτωση, όπου όχι μόνο ο σκεδαστής αλλά και ο χώρος σκέδασης είναι ανισότροποι χώροι και μάλιστα έχουν διαφορετικά χαρακτηριστικά. Όπως προκύπτει, τα χαρακτηριστικά του ανισότροπου μέσου μεταφέρονται πλήρως από έναν τροποποιημένο τελεστή κλίσης, ο οποίος εμφανίζεται σε κάθε περίπτωση ανισοτροπίας και μας επιτρέπει να βρούμε τη θεμελιώδη λύση της τροποποιημένης εξίσωσης Helmholtz. Δεδομένης της θεμελιώδους λύσης, τοποθετείται το βασικό πρόβλημα σκέδασης σε ανισότροπα μέσα όπως και οι συνθήκες διαπερατότητας καθώς και οι συνοριακές συνθήκες. Στη συνέχεια παρουσιάζεται η μορφή και οι ιδιότητες των προσπίπτοντων πεδίων και παράγονται τα συναρτησιακά ενέργειας για αυτό το πρόβλημα σκέδασης. Αναπτύσσονται οι ολοκληρωτικές αναπαραστάσεις για το σκεδαζόμενο, το ολικό και το εσωτερικό πεδίο, ενώ παράλληλα προκύπτει η τροποποιημένη συνθήκη ακτινοβολίας και με αυτό τον τρόπο ολοκληρώνεται η βασική θεωρία. Με ασυμπτωτική ανάλυση προκύπτει το ανισότροπο πλάτος σκέδασης και έπειτα ορίζονται οι ενεργειακές διατομές που αντιστοιχούν στην περίπτωση που εξετάζεται. Ακολούθως αποδεικνύονται τα θεωρήματα αμοιβαιότητας, το γενικευμένο και το οπτικό θεώρημα σκέδασης για τα ανισότροπα μέσα. Ως εφαρμογή παρουσιάζεται το πρόβλημα σκέδασης χαμηλών συχνοτήτων για έναν ανισότροπο διαπερατό σκεδαστή. Τέλος, όλο το πρόβλημα ανισότροπης σκέδασης ανάγεται στο αντίστοιχο του ισότροπου χώρου, προς επιβεβαίωση των αποτελεσμάτων. / Scattering theory covers a large spectrum of scientific and technological applications such as non destructive control, radars, sonar, geophysical exploration, remote sensing, medical imaging, under-water acoustics, seismology, biological pattern recognition and special techniques in medical diagnostics. In most of the above cases the assumption that the material is isotropic is inadequate. Therefore, in order to conform to reality, we have to accept that the space is anisotropic, i.e. its properties depend on the direction. Although the anisotropic property was already known, since Green’s era, only a few publications have appeared, due to the mathematical complexity related with the anisotropic property. It was during the last years that more references considered the anisotropic scattering, while most of them regarded only anisotropic scatterers. The thesis examines the problem of scalar field anisotropic scattering for the general case, where not only the scatterer but also the propagation space are anisotropic and they do not have the same characteristics. It comes out that the characteristics of an anisotropic medium are being fully carried by a modified gradient operator which appears in any case of anisotropy and allows the calculation of the fundamental solution for the modified Helmholtz’ equation. Once the fundamental solution is known, the basic problem of anisotropic scattering is postulated as well as the transmission and the boundary conditions. Incident fields’ forms and characteristics are being presented and the energy functional for this scattering problem is being produced. The integral representations for the scattered, total and internal field are also developed, while at the same time arises the modified radiation condition. Asymptotic analysis produces the anisotropic scattering amplitude and afterwards follows the definition of the energy functionals that correspond to our case. The reciprocity theorems, the general scattering, as well as the optical theorem for anisotropic medium are also proved. As an example, the theory developed in this thesis is applied to the low frequency problem for an anisotropic scatterrer. Finally, the results are verified by reducing the whole problem of anisotropic scattering to its equivalent of isotropic space.

Summaries in English and Afrikaans / Across the world children are affected by factors such as poverty, HIV/AIDS, divorce and loss. More organisations are getting involved in the training of voluntary counsellors. Although these counsellors have the necessary theoretical knowledge they still experience problems in working effectively with these children. Possible reasons for this are these counsellors' own unfinished issues and loss. Within this study the focus is on creating awareness for counsellors within training situations from a Gestalt approach. As part of the fulfilment of the literature study an empirical study has been done. A qualitative study with a small portion of quantitative research has been done with the implementation of a training programme for voluntary counsellors. Various mediums were used to create heightened self-awareness with regard to various topics. Training guidelines are than given for creating awareness within training situations for voluntary counsellors. / Dwarsoor die wereld word kinders beinvloed deur faktore soos armoede, HIV/VIGS, egskeiding en verlies. Al meer organisasies, soos Philippi Trust Namibia, raak betrokke in die opleiding van vrywillige beraders, ten einde bekostigbare dienste vir hierdie kinders daar te stel. Alhoewel hierdie beraders oor voldoende teoretiese kennis beskik, ervaar hulle steeds probleme om effektief met kinders te werk. Moontlike redes is vrywillige beraders se eie onvoltooidhede en verlies. Binne hierdie studie word op die bewusmaking van beraders binne opleidingsituasies gefokus ten einde selfbelewing daar te stel. 'n Literatuurstudie is gedoen waartydens aspekte bekom is: teoretiese perspektief op die volgende > Bewustheid en die vrywillige berader vanuit die Gestalt-benadering. > Riglyne binne opleidingsituasies vir verhoogde bewustheidsbelewing. Deur bogenoemde teoretiese perspektief word die eerste navorsingsdoelwit van die studie beantwoord. Ter aanvulling van die literatuurstudie is empiriese ondersoek ondermeem. Kwalitatiewe studie met kleiner komponent van kwantitatiewe navorsing is voltooi deur die implementering van 'n program vir vrywillige beraders. Die program het oor vyf dae geskied. Verskeie mediums is gebruik om selfbelewing rondom spesifieke onderwerpe te verhoog. Deur bogenoemde empiriese ondersoek word die tweede doelwit van die studie beantwoord. Na aanleiding van die studie word opleidingsriglyne vir die verhoging van bewustheid binne opleidingsituasies vir vrywillige beraders daargestel. / Social work / M. Diac. (Play Therapy)

No / Security is a function of the trust that is associated with the active variables in a system. Thus, the human factor being the most critical element in security systems, the security perimeter could be defined in relation to the human trust level. Trust level could be measured via positive identification of the person/device on the other side of the interaction medium, using various authentication schemes; location-based being one of the latest. As for the location-based services, the identity of a customer remains hazy as long as his location is unknown; he virtually remains a ghost in the air, with implications on trust. This paper reviews the various location-based authentication techniques with a focus on the role that GPS could play in optimising this authentication approach. It advocates the urgent need to make all transmission devices GPS-compliant as a way forward, despite the privacy issues that might arise.

It is common knowledge that owing to their particular vulnerability children worldwide falls prey to physical and/or sexual violence in the home and/or community or witness criminal acts. Consequently children are called upon to testify in a court of law to cruelties or acts of violence. As a result of their developmental shortcomings and immaturity, children find the criminal justice system extremely intimidating and challenging. The importance of realising a justice system that not only affords an accused person the right to a fair trial but also protects and safeguards the rights of the child victims of and witnesses to the crime is thus indisputable. The purpose of this research was therefore to assist the South African criminal justice system in its on-going challenge to find a balance between the right of the accused person to a fair trial and the protection and safeguarding of the rights of child victims and child witnesses. The protection and safeguarding of the rights of child victims and child witnesses in terms of the South African Constitution, applicable domestic law and international instruments relating thereto were extensively discussed and shortcomings identified. Possible solutions to ensure that child witnesses and child victims are adequately protected and supported during the trial stage of the criminal process were advanced. Particular emphasis was placed on the role of an intermediary in assisting child victims and child witnesses during the court process. Comparative research on the protection of child victims and child witnesses in the criminal justice systems of New Zealand and Namibia were also conducted. Conclusions drawn from comparative studies were used to recommend appropriate changes to the current system. It is submitted that the adequate protection and safeguarding of the rights of child victims and child witnesses are dependent not only on sound legal principles but also on governmental and other involved stakeholders’ commitment toward the realisation of these rights. In order to give proper effect to the protection and safeguarding of child victims’ and child witnesses’ rights, it is proposed that the recommendations made throughout this study should be adopted and implemented. In this regard the role of an intermediary is crucial and the use of intermediaries should be promoted. / Private Law / LL.D.