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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Untersuchung zum Gesichtswachstum von Patienten mit Lippen-Kiefer-Gaumenspalten operiert nach dem Leipziger Konzept zur funktionellen Rehabilitation von Lippen-Kiefer-Gaumenspalten: Untersuchung zum Gesichtswachstum von Patienten mit Lippen-Kiefer-Gaumenspalten operiert nach dem Leipziger Konzept zur funktionellen Rehabilitation von Lippen-Kiefer-Gaumenspalten

Tzeuschner, Dominique 07 April 2014 (has links)
In der vorliegenden Dissertation wurde anhand von 1042 extraoralen Fotos im Profil und en face untersucht, wie sich das Wachstum longitudinal bei 166 gesunden Kindern, je zehn Kindern mit isolierter Gaumenspalte, einseitiger Lippen-Kiefer-Gaumenspalte sowie doppelseitiger Lippen-Kiefer-Gaumenspalte operiert nach dem Leipziger Konzept entwickelt, sowie inwiefern sich die einzelnen Gruppen in verschiedenen Altersstufen voneinander unterscheiden. Dazu wurden pro Gruppe jeweils fünf Jungen und fünf Mädchen kaukasischer Herkunft, geboren in den Jahren 1994 bis 2001, mit einer nichtsyndromalen Spalte ausgewählt, die ab der Geburt über mehrere Jahre hinweg fotografiert wurden. Diese Fotos wurden digitalisiert und denen von Kontrollpatienten gegenüber gestellt. Anhand von Winkeln der klassischen Morphometrie und Grafiken und Statistiken der geometrischen Morphometrie wurden die Veränderungen im Wachstum analysiert und die Kontrollpatienten mit dem Leipziger OP-Konzept verglichen. Es konnte gezeigt werden, dass die geometrische Morphometrie durchaus geeignet ist, das Gesichtswachstum anhand von extraoralen Fotos zu beurteilen. Weiterhin konnte bestätigt werden, dass mit dem Leipziger Konzept zur funktionellen Rehabilitation von Patienten mit Lippen-Kiefer-Gaumenspalten sehr gute Operationsergebnisse und vor allem Langzeitergebnisse erzielt werden können.
182

Shape Change and Variation in the Cranial Morphology of Wild Canids (Canis lupus, Canis latrans, Canis rufus) Compared to Domestic Dogs (Canis familiaris) Using Geometric Morphometrics

Schmitt, E., Wallace, S. 01 January 2014 (has links)
Wild canid populations exhibit different anatomical morphologies compared to domesticated dogs in North America. This is particularly important concerning archaeological sites, which may contain early domesticated species, for the proper identification of osteological remains. Previous studies have indicated domestic dogs exhibit a shorter rostrum accompanied by a crowded tooth row; however, none describe the overall complexity of these changes. Consequently, using a landmark-based geometric morphometric analysis, cranial morphological characteristics were examined in North American wild canids: the gray wolf (Canis lupus), coyote (Canis latrans), red wolf (Canis rufus), and the domestic dog (Canis familiaris). The shape and size of the cranium in lateral and ventral views were compared between the three wild species to the group of domesticated dogs. Wild canids clustered separately from the domestic group in all statistical analyses. Results indicate an expansion of the orbital region, a compression of the rostrum, and an overall warping in the shape and orientation of the skull. In domestic species, there is also a downward shift in the frontal portion of the skull accompanied by the braincase assuming a more upward position. This technique successfully depicted how slight changes in isolated areas of the cranium can have an impact on the overall shape and morphology of the skull. We presume these changes in cranial anatomy reflect the recent selective pressures domestic dogs have undergone since diverging from their wild ancestors.
183

Vitis Seeds (Vitaceae) From the Late Neogene Gray Fossil Site, Northeastern Tennessee, U.S.A.

Gong, Fade, Karsai, Istvan, Liu, Yu Sheng C. 01 August 2010 (has links)
This study focuses on morphometric and systematic analyses of the fossil Vitis seeds, recovered from the Gray Fossil Site (7-4.5. Ma, latest Miocene-earliest Pliocene), northeastern Tennessee, U.S.A. A multivariate analysis based on eleven measured characters from 76 complete fossil seeds recognizes three morphotaxa. Further comparisons with both selected modern and fossil vitaceous specimens confirm that these morphotaxa represent three new species, viz. Vitis grayensis sp. nov., Vitis lanatoides sp. nov., and Vitis latisulcata sp. nov. Furthermore, the close resemblance of the first two fossil grapes (V. grayensis and V. lanatoides) with two East Asian Vitis species provides further support concerning a strong eastern Asian aspect of the Gray fossil biota in the late Neogene southeastern North America, as previously evidenced by both animals (e.g. Pristinailurus bristoli [red panda]) and other plants (e.g. Sinomenium and Sargentodoxa).
184

Differentiating Microtus Xanthognathus and Microtus Pennsylvanicus Lower First Molars Using Discriminant Analysis of Landmark Data

Wallace, Steven 01 December 2006 (has links)
The distinct ecological requirements of Microtus xanthognathus (yellow-cheeked vole or taiga vole) and M. pennsylvanicus (meadow vole) warrant accurate discrimination of their remains in studies of paleoecology and past biogeographical shifts. An occlusal length of the lower 1st molars (ml) that is >3.2 mm for M. xanthognathus is the method most frequently used to separate these 2 taxa in archaeological and paleontological samples. However, these measurements alone are unreliable because some specimens of M. pennsylvanicus overlap smaller individuals of M. xanthognathus in size. Therefore, I created and tested a morphometric technique that discriminates Recent lower 1st molars (mis) of M. pennsylvanicus from those of M. xanthognathus, and is applicable to other taxa (both modern and fossil). Despite overlapping occlusal length, my discriminant function based on landmark data correctly classified 100% (n = 53) of Recent m1s from the 2 taxa and 97.7% (43 of 44) of (assumed) m1s of M. pennsylvanicus from an archaeological site from about AD 1200 in central Nebraska. This landmark scheme is applicable to fossil and modern Microtus worldwide. © 2006 American Society of Mammalogists.
185

A Systematic Revision of <i>Passiflora</i> Section <i>Dysosmia</i> (Passifloraceae)

Svoboda, Harlan T. 01 October 2018 (has links)
No description available.
186

Quantifying the link between craniodental morphology and diet in Soricidae using geometric morphometrics

Tse, Yuen Ting January 2020 (has links)
No description available.
187

Characterizing phenotypic diversity in marine populations of threespine sticklebacks

Fraser, Ainsley 26 April 2021 (has links)
The threespine stickleback (Gasterosteus aculeatus) is an important model for studying evolution. Sticklebacks are widely distributed in the northern hemisphere and inhabit freshwater, brackish, and marine waters. Anadromous and marine populations (hereafter marine) are assumed to be homogenous in space and invariant in time in their phenotypic characteristics, despite marine environments varying on regional and local scales. Recent studies suggest there is in fact genetic and phenotypic structure in marine sticklebacks, yet the ecological causes remain unclear. My goal was to assess trait variation in marine stickleback populations around Southern coastal British Columbia (BC), and to determine whether or not oceanographic and habitat characteristics explained this variation. The area around Vancouver Island was ideal because four distinct oceanographic regions surround the island with varying coastal habitat types. Between May-July 2019, I sampled ~600 sticklebacks from 15 sites. I then characterized trait variation using two-dimensional (2D) geometric morphometric analysis to compare individuals between oceanographic regions and coastal habitats. I focused on five traits: armour phenotype, head size, body size, head shape, and body shape. I chose these traits because they are ecologically important and well-studied in freshwater populations, where their ecological drivers are known. I found that marine sticklebacks did vary morphologically among and between regions and habitats, but the variation was not immediately related to environmental variation, nor obviously comparable to variation in freshwater populations. Sexual dimorphism was the largest source of variation in the data, a well-established finding. But oceanographic and habitat variables influenced differences between males and females. I concluded that marine sticklebacks offer abundant opportunities for expanding our knowledge of drivers of morphology in nature. / Graduate / 2022-04-11
188

Untersuchungen zur Morphologie von dentofazialen und skelettalen Strukturen Erwachsener mit Methoden der geometrischen Morphometrie

Krey, Karl-Friedrich 28 September 2010 (has links)
Bibliographische Beschreibung: Krey, Karl-Friedrich Untersuchungen zur Morphologie von dentofazialen und skelettalen Strukturen Erwachsener mit Methoden der geometrischen Morphometrie Universität Leipzig, Habilitation 251 S., 319 Lit.,109 Abb., 93 Tab. Referat: Die kieferorthopädische Diagnostik beruht neben der klinischen Untersuchung auf der metrischen Auswertung (Streckenmessungen, Winkelmessungen, Verhältniszahlen) von standardisierten extraoralen Fotos, Fernröntgenseitbildern und Modellen der Kiefer. Diese Verfahren werden denen der klassischen Morphometrie zugerechnet. In den letzen Jahren hat sich eine Vielfalt neuer Verfahren zur Analyse von biologischen Formen etabliert. Diese geometrische Morphometrie kann als Synthese multivariater statistischer Analysen kartesischer Koordinaten angesehen werden. Sie stellt eine effiziente, alle Eigenschaften von geometrischen Unterräumen abbildende Methode zur Beschreibung biologischer Formen unter Beibehaltung aller räumlichen Beziehungen dar. In der vorliegenden Untersuchung wurden diese Methoden umfassend auf die Befunde von erwachsenen Kaukasiern angewendet. Es handelte sich dabei um 179 extraorale Fotos jeweils en face und im Profil, 463 Fernröntgenseitbilder und 242 Modelle kieferorthopädisch unbehandelter Erwachsener. Ziel war es, mit den Methoden der geometrischen Morphometrie anhand dieser Befunde die Form, Größe und deren Variabilität in Abhängigkeit vom Geschlecht und Klassifikationen der klassischen Morphometrie zu beschreiben, und damit grundlegende Daten für die Etablierung dieser Verfahren in der Kieferorthopädie bereitzustellen. Für die untersuchten dentofazialen Strukturen konnten mit sexuellem Dimorphismus einhergehende Größenunterschiede festgestellt und in Abhängigkeit von bestimmten skelettalen Konfigurationen erstmals differenziert und quantifiziert werden. Die Betrachtung der Form des Gesichtes, repräsentiert durch die extraoralen Fotos, zeigte charakteristische geschlechtsspezifische Veränderungen sowie Eigenschaften, die nicht mit der Konfiguration der entsprechenden skelettalen Strukturen korrelierten. In der Analyse der Fernröntgenseitbilder konnten Veränderungen der vertikalen Dimension als ein für die Form bestimmender Faktor identifiziert werden. Auch für die untersuchten Modelle konnten in der Stichprobe die Varianz bestimmende Faktoren isoliert werden. Der gewählte mathematisch-statistische Ansatz ermöglichte die Beschreibung unterschiedlicher (zwei- und dreidimensionaler) Strukturen mit einem einheitlichen Repertoire an Verfahren. Es konnte gezeigt werden, dass die angewendeten Methoden in der Lage sind, die dentofaziale und skelettale Morphologie adäquat und vollständig numerisch und visuell zu beschreiben sowie klinisch relevante Fragestellungen zu beantworten.
189

Factors affecting morphometrics and epiphyseal closure of white-tailed deer

Flinn, Emily Brooke 07 August 2010 (has links)
Factors affecting morphometrics and epiphyseal closure are important in understanding regional variation and growth of white-tailed deer (Odocoileus virginianus). I compared body and antler growth from birth to 3 years of age in captive, first-generation, male white-tailed deer from three regions with varying soil quality and deer morphometrics. I also determined gender and age effects on epiphyseal closure timing in captive white-tailed deer. I found regional morphological variation present in first-generation male deer, which may be caused by regional genetic variation or lingering maternal effects. Determining cause of regional morphological variation will require data collection through a second-generation of males raised on the controlled diet. Epiphyseal closure timing was associated positively with age. Two of the four epiphyseal plates examined were affected by gender, with females closing prior to males. Morphometric and epiphyseal data confirm that age and gender affect epiphyseal closure timing in white-tailed deer.
190

The Origin of Banana Holes on San Salvador Island, the Bahamas

Infante, Louis R 12 May 2012 (has links)
Banana holes are a common karst feature of The Bahamas and several theories have been presented to explain their origin. The current model for banana hole formation places their dissolution at the mixing zone at the top of the fresh water lens. This theory is based on the observation that banana holes are often found in the interior of islands, far from the dissolutionally aggressive fresh water lens margin. This study proposes that banana holes form at the lens margin as it follows a prograding strandplain. Spatial observations show that banana holes appear to be associated with low inland ridges and their orientation appears to correlate with features found on modern shorelines. Bedding features such as herringbone cross beds and back-beach rubble found in banana hole wall rock point to a progradational environment of deposition for banana hole host rock.

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