Thesis (Ph. D.)--University of Adelaide, Dept. of Botany, 1990. / Includes bibliographical references (leaves 151-184).

Dissertation (PhD)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

No description available.

No description available.

No description available.

Lichens are an underrepresented group of organisms when it comes to both research and conservation efforts. At the same time, lichens face increasing threats from anthropogenic sources including wildfires, climate change and urbanization. With this thesis, I seek to ascertain and publish ecological data on a critically endangered lichen to inform future conservation designations and efforts to preserve and protect the species in perpetuity. In Chapter 1, I provide an ecological overview of the known range of Sulcaria isidiifera and assess the status of Sulcaria isidiifera via a population count. Sulcaria isidiifera occurs in maritime chaparral habitat in the Los Osos-Baywood Park-Morro Bay area of San Luis Obispo County, California. Although apparently similar maritime chaparral is known from a much larger range along the coast of California, S. isidiifera has never been found outside of this extremely local population area. Population data collected during the study determined there are an estimated 3,588-7,772 mature individuals of S. isidiifera range-wide. Chapter 1 also characterizes the vascular plant vegetation community, microclimate parameters, and lichen community assemblage in which S. isidiifera occurs. The elegant fringe lichen (Leucodermia leucomelos) was found to be a strong indicator for the presence of S. isidiifera. Chamise (Adenostoma fasciculatum), buck brush (Ceanothus cuneatus), and Morro manzanita (Arctostaphylos morroensis) were the most common shrub species on which S. isidiifera was found. In Chapter 2, conservation translocation was tested as a mitigation strategy for the previously observed population decline of S. isidiifera. Whole thalli were translocated while attached to their original substrate to adjacent shrubs in suitable habitat that was not occupied by S. isidiifera. The vitality of translocated thalli was tested using chlorophyll fluorescence techniques. After 13.5 months, I report 100 percent survival of translocated thalli with no significant negative impacts to thallus health. The S. isidiifera transplants will continue to be monitored indefinitely. Guidance on future conservation translocations for S. isidiifera is provided and these methods will continue to be updated as further observations and results are gathered.

Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Title from first page of PDF file (viewed March 18, 2010). Includes bibliographical references. Issued in print and online. Available via ProQuest Digital Dissertations.

The chromosomes involved in twenty reciprocal translocations in G. hirsutum were reidentified by means of a specially designed crossing program. Each translocation line was crossed to appropriate monosomic, monotelodisomic, and/or translocation lines. The F₁ hybrids were then scored cytologically to verify the original chromosome identification. These twenty reciprocal translocations now become the cytogenetic tester set for G. hirsutum. Seed stocks for each verified translocation line will be maintained at, and distributed by, the University of Arizona. Nineteen of the twenty heterozygous translocations had a modal chiasma frequency per quadrivalent of four. Fourteen of these translocation lines formed predominantly ring multivalents at MI, and the remaining five translocations usually formed multivalents with at least one interstitial chiasma. One translocation line, which was originally produced by an interspecies cross, formed predominantly chains at MI. This increased amount of chaining in the quadrivalent is probably the result of interspecific chromosome material within the translocation reducing the chiasma frequency. The orientation of the centromeres in quadrivalents is influenced by the size of the chromosomes involved in the reciprocal translocation, and the constraints imposed by the chiasmata within the chromosome arms. Ten of the twenty reciprocal translocations studied formed predominantly alternate orientations at MI. Eight of these ten translocation lines were reciprocal translocations between two A subgenome chromosomes. This suggests that the large A subgenome chromosomes allow the quadrivalent to be more flexible, resulting in easy reorientation to the stable alternate configuration. Proximal chiasma formation influences the orientation and probable involvement of the homologous centromeres in spindle formation. Lines in which a high frequency of multivalents with interstitial chiasma were observed had a significantly lower frequency of multivalents with either one or two centromeres not involved in spindle formation of 3:1 orientations. In most of the heterozygous translocations, identification of each chromosome within the quadrivalent at MI was not possible. Estimation formulae were developed to estimate the positions of the breakpoints and the genetic lengths of each segment defined by multivalents in these translocations.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Afin de faciliter le séquençage des génomes, une troisième génération de systèmes de séquençage est nécessaire. La translocation de biomolécules est le phénomène clé mis en jeu dans l'optique d'un séquençage par nanopore. Nous nous sommes intéressé à ce phénomène avec une approche à la fois théorique et numérique. Dans le cadre de nos travaux, nous avons tout d'abord élaboré un modèle dit gros grain de polymère structuré (présentant une structure proche de celle de l'ADN) adapté à une étude par dynamique moléculaire. Après avoir vérifié la pertinence de notre modèle avec les lois de la physique statistique des polymères, nous nous sommes concentrés sur la translocation. Nous avons revisité le cas standard d'un nanopore au sein d'une membrane fixe et proposé un modèle théorique dans le cas de la traction du polymère. L'arrivée des membranes fines, clés du succès d'un éventuel séquençage non destructif par nanopore entraine de nouvelles intéractions avec la membrane qui n'ont pas encore été étudiées. Nous présentons la première étude numérique de grande ampleur sur ses intéractions. Nos résultats permettent d'étudier l'influence des vibrations, de la déformabilité et de la flexibilité de la membrane. / So as to facilitate genomic sequencing, a third generation of sequencing devices is needed. Biopolymer translocation is the key phenomenon involved in nanopore sequencing prospects. We investigated this phenomenon through both theoretical and numerical approaches. Our work started with devicing a coarse grained structured polymer (with a DNA like structure) adapted to a molecular dynamics study. Once we have verified the reliability of our model towards statistical polymer physics, we focused on translocation. We reinvestigated the common case of a nanopore within a fix membrane and proposed a theoretical model for translocation under a pulling force. The arrival of thin membranes is key to an eventual success of non destructive sequencing with a nanopore. This enables new interactions with the membrane which have not been investigated yet. We provide the first large scale numerical investigation of such interactions. our results provide an insight over the influence of membrane vibrations, deformability and flexibility.