Cranial vault thickness (CVT) has been reported at many different osteometric landmarks and features on the vault. Historically, only a few landmarks are used, often bregma, lambda, vertex, and right and left euryon, and frequently comparisons are based only on “thick” versus “thin” to describe the vault overall. What is inherent in this strategy is the use of a few locations to characterize the entire vault. The problem remains that there is little information concerning CVT variation throughout an individual's vault, and the causes of variation within recent Homo sapiens important to investigating thickness variation between species in Homo. This work describes thickness variation over the entire superior vault and compares the sexes, age groups and populations in recent H. sapiens. A proportional grid is applied to the superior vault to measure thickness at 219 sampling points in a geographically diverse sample of recent H. sapiens. Thickness values are analyzed in their two-dimensional spatial relationships to determine patterns of vault thickness. Males were identified to be thicker than females at more lateral locations and along the midsagittal plane, although this finding is not statistically significant. Individuals over the age of 45 years are found to be statistically significantly thicker than individuals younger than 31 years at more lateral locations of the vault. Aboriginal Australians are statistically significantly thicker at more lateral locations of the vault than any other populations, whereas Northern Canada/Greenland individuals were thinner than other populations at these locations. The trend of thicker vaults in the older age group and the Australians is identified across the vault, although is not statistically significant at more locations. Several thickness patterns are identified. The boss thickening pattern is the most common pattern, followed by a midsagittal pattern, a posterior pattern, and an anterior pattern. Some specimens do not demonstrate thickness variation and are coded as undifferentiated. Each pattern is observed alone and in combination with others, signifying that pattern causes are not mutually exclusive. Boss thickening is interpreted as the result of passive bone thickening during normal bone and brain growth during fetal and adolescent development. The midsagittal thickness pattern coincides with inferred strain along the sagittal suture from nuchal muscle engagement during mastication. Previous researchers have proposed adaptive explanations for thickness variation, such as protection from interpersonal violence; the patterns of cranial vault thickness reported here point to normal growth and development of the brain as a driving force, a relationship that could drive thickness variation in other Homo species. Comparing thickness at bregma, and the frontal and parietal eminences for recent H. sapiens and H. erectus, there is no statistical difference between African and Asian H. erectus, and between the on average thicker H. sapiens populations and H. erectus, based on published data. Future work will investigate the presence or absence of thickness patterns in these fossil species.

A graph is planar if it can be drawn on a piece of paper such that no two edges cross. The smallest complete and complete bipartite graphs that are not planar are K5 and K{3,3}. A biplanar graph is a graph whose edges can be colored using red and blue such that the red edges induce a planar subgraph and the blue edges induce a planar subgraph. In this thesis, we determine the smallest complete and complete bipartite graphs that are not biplanar.

Introduction: The aim of this in vitro study was two part. The first being to assess and compare the amount of dentin removed by an instrument with a taper of 0.04 versus an instrument with a taper of 0.06 using the Edge Evolve® file system at different increments within the canal system. Secondly, this study evaluated whether instrumentation with either taper resulted in a remaining dentin thickness (RDT) of less than 0.3mm. If this RDT was imposed upon, fracture resistance was compromised. Both pre and post instrumentation measurements were taken of samples instrumented with the 0.04 and 0.06 tapered files. Methods: Ten maxillary premolars exhibiting Weine class III canal systems and minimal to no root canal curvature were mounted in an acrylic resin filled K-cube. Each acrylic resin cube was sectioned horizontally at 3, 6, 9, and 12mm increments from the apex. The K-cube is a device which allows the investigator to disassemble and then reassemble root slices in their original orientation. Dentin thickness was measured at three positions on each canal using the Zeiss Discovery V20 stereomicroscope. The sections were then reassembled into the K-cube. The ten premolar roots were separated into two groups. In half of the teeth the buccal canals were instrumented with 0.04 tapered files and the lingual canals instrumented with 0.06 tapered files. In the other half of the teeth, instrumentation was reversed: the buccal canals were instrumented with 0.06 tapered files and the lingual canals were instrumented with 0.04 tapered files. Root sections were again separated, and the remaining dentin thickness was measured. A repeated-measures mixed-model ANCOVA was performed to analyze the effect of taper on RDT. Results: The amount of dentin removed was statistically different between the two tapers (P=0.02). Across all of the slices and positions, the 0.04 tapered instruments had an average pre-post difference of 0.1313mm. The 0.06 tapered instruments had an average pre-post difference of 0.1672mm. None of the instruments imposed upon the recommended 0.3mm RDT. Conclusion: The 0.04 tapered files instrument with greater conservancy than the 0.06 tapered files. The 0.06 tapered files had their greatest effect on the canal in the 9mm and 12mm sections. However, neither taper imposed upon the recommended RDT for optimal fracture resistance within the apical 12mm root portion observed in this study. Keywords: Instrumentation, Edge Evolve, Root canal preparation, Taper

The ecology of plant species at Sandford Rocks Nature Reserve (SRNR) was studied. The study site is an important nature reserve that contains relatively undisturbed natural vegetation. It has a mosaic of exposed granite rocks, scrublands and woodlands. The study involved: a description of the structure and composition of the vegetation; the population characteristics of selected Acacia species; aspects of reproduction in Acacia; germination and seedling characteristics of some Acacia and grass species that dominate the reserve; the effect of seed size on germination and seedling characteristics; and, the relationship of seed size to seed coat thickness in selected Acacia species. Five different areas were studied using the point centered quarter method to sample the woody perennial species. Thirteen Acacia species were examined for reproduction characteristics; and in 2 selected Acacia species, the effects of phyllode and/or inflorescence removal on reproduction was investigated. Germination tests were conducted to identify germination characteristics in 8 Acacia and 7 grass species dominant at SRNR. The possible effects of variation in seed size on germination; seedling characteristics; and, seed coat thickness were investigated in Acacia fauntleroyi and Acacia prainii. A total of 85 species from 20 families of woody perennials were collated. All areas were dominated by the Myrtaceae, Mimosaceae and Proteaceae families. There was considerable variability in the structure and composition of vegetation. Most species were present in particular sites and the composition of communities appears to be related to the heterogeneity of the habitat within the reserve. In areas of shallow or rocky soil, vegetation types present include Allocasuarina huegeliana woodland, Grevillea paradoxa low scrubland and Acacia neurophylla medium shrubland. / In a seasonally wet area, vegetation types present include low open grassland; Eucalyptus capillosa (wandoo) woodland; and, Acacia saligna thicket. In deep, dry sandy soil, vegetation types include Phebalium tuberculosum shrubland, Acacia acuminata and Acacia coolgardiensis thickets. On relatively flat areas that gain water from adjacent large granite hills, the vegetation consists mainly of tall, open woodlands of Eucalyptus species. Vegetation types include: medium tall Eucalyptus salmonophloia woodland with Kunzea pulchella shrubland at the periphery of the Eucalyptus woodland. At rock areas, vegetation types present include dense Leptospermum erubescens thicket, low open Acacia prainii and Dodonaea viscosa shrubland. Of the Acacia populations studied, in A. lasiocalyx no recent seedling establishment was observed. It is hypothesised that recruitment occurs in particular periods. As the plants are associated with rock and soils are generally shallow, it appears that recruitment depends on run-off water from the rocks in winter. Continuous recruitment seems to be the pattern in A. prainii with both seedlings and saplings represented. A. fauntleroyi forms relatively small populations; apparently long drought periods (>l00 d) result in mass death and limit its population size. In A. hemiteles, no seedling stage was found, root competition (for water) from associated Eucalyptus species presumably limits its recruitment. Reproductive success of Acacia is affected by rainfall. A wet winter is required to induce flowering and further rain is required after flowering to promote pod development and good seed set. / All Acacia species suffer from drought in the reproduction season, however they differ in their degree of susceptibility. Leaflessness and tree shape also affect Acacia fecundity. Plants bearing more phyllodes produce more flowers and pods, and branches in the upper part of the crown bear heavier inflorescences. In 1998, all Acacia species at SRNR produced mature seed of low weight, with many immature and diseased seed, which gave poor germination. A late spring frost in 1998 is believed to be responsible for limited seed development. In two selected Acacia species, removal of phyllodes reduced the number of pods produced. Presumably, phyllode removal reduces photosynthate produced, therefore the competition among inflorescences (or pods) for resources is more intense and subsequent abortions are likely to occur. All Acacia species studied showed best germination in the cool winter temperature range. Apparently, seeds are adapted to germinate in winter when seasonal moisture is more likely to be available. The best temperature however, varied slightly between species. The grass species dominant in the reserve, except for Aristida contorta, also had more germination in cooler rather than warmer temperatures. The flora of SRNR is similar to typical vegetation of the Southwest. Generally, Acacia species are present only in particular sites, presumably were habitat moisture allows. Seedlings of Acacia species growing in naturally dry areas have greater root: shoot masses than those growing in seasonally wet areas. Biomass partitioning is an apparent strategy to conserve water. Of the 7 grass species, Amphipogon strictus appears to have fastest growth. / Eriachne ovata has greater root than shoot mass, while in all other species, shoot mass is greater than root mass; a characteristic of species that grow well in moist habitats. The longest shoots and roots are in Austrostipa elegantissima, an understorey species of eucalypt woodland. In A. fauntleroyi, the degree of hard-seededness varies between seed sizes. There is a higher proportion of soft seed in smaller seed. Seed of different sizes show some responses to different pre-treatments and incubation temperatures for germination. Larger seeds generally germinate in greater numbers after higher treatment temperatures. The best treatment for small seeds is pre-treatment at 75°C and incubated at 15°C. For medium and large seed, best pre-treatment is at 75°C with incubation at 30°C or soaking in boiling water and incubation at either 15 or 3°C. In A. prainii, seed size; pre-treatment; incubation; and, their interaction all affected germination; larger seeds are more viable. The best treatment to promote germination of A. prainii is soaking in boiling water and incubation at 25°C. In both A. fauntleroyi and A. prainii, larger seeds produce larger seedlings. Seedlings from large seeds have the potential for more rapid pre-photosynthetic growth. Larger, heavier seed has a thicker seed coat. The seed coat of A. prainii is thicker than in A. fauntleroyi; the difference in seed coat thickness is reflected by more soft seed in A. fauntleroyi (35%) than in A. prainii (6%).

Orthokeratology (OK) is the reduction, modification or elimination of myopia through application of contact lenses. With the development of high Dk/t lens materials, overnight therapy has become the modality of choice for OK. Overnight OK lens wear has been previously investigated in terms of its efficacy to reduce myopia. However, the underlying effects of overnight OK lens wear on the human cornea have received less attention. As well as the clinical efficacy of overnight OK, this study investigated the effects of overnight OK on topographical corneal thickness and the overnight corneal edema response, and corneal tissue changes with overnight OK. Eighteen subjects participated as the OK lens-wearing group, wearing BE lenses (UltraVision, Brisbane, Queensland) in both eyes. A further ten subjects participated as control subjects, wearing conventional rigid lenses (J-Contour, UltraVision) in the right eye (RE) only. The left eye (LE) acted as a non-lens-wearing control. Both groups wore lenses overnight only, with no lens wear during the day. Measurements were conducted at baseline then on day 1, 4, 10, 30, 60, and 90 for the OK lens-wearing eyes; and up to day 30 for the control group, in the morning (after overnight lens wear) and in the evening (after 8-10 hours of lens removal). Variables measured included best vision sphere (BVS), unaided logMAR visual acuity (VA), refractive astigmatism, apical corneal power (ACP), simulated K readings (Medmont E300 corneal topographer), topographical corneal thickness (Holden-Payor optical pachometer), and keratocyte and endothelial cell densities (ConfoScan2 confocal microscope). Approximately 75% of myopia was corrected after the first night of OK lens wear and the changes in refractive error stabilised by day 10. By day 90, myopia reduction averaged 2.54 ?? 0.63 D. This was associated with significant improvement in unaided VA of about 82% after the first night of lens wear. There was no change in refractive astigmatism over the 3-month period. There was significant reduction in ACP in the OK lens-wearing eyes after the first night of lens wear, which accounted for more than 70% of the total ACP change over the 3-month period (RE: -2.16 ?? 0.53 D; LE: -2.11 ?? 0.86 D). There was significant central epithelial thinning (about 30%) and significant thickening (about 3%) in the mid-peripheral stroma in the OK lens-wearing eyes. Significant central epithelial thinning was found after the first night of lens wear while thickening in the mid-peripheral stroma reached statistical significance by day 4. Further analysis suggests that topographical corneal thickness changes account for the refractive error changes with overnight OK lens wear, rather than corneal bending. The central overnight stromal edema response was significantly reduced in the OK lens-wearing eyes (1.2 ?? 0.5%) to a level lower than in the conventional RGP (6.2 ?? 1.2%) and non-lens-wearing eyes (2.5 ?? 0.9%) in the control group. Mid-peripheral and peripheral stromal edema responses showed similar levels to those predicted based on lens Dk/t. A single overnight wear of BE and Paragon Corneal Refractive Therapy (CRT) lenses showed that the edema response to BE lens wear is significantly less than in the CRT lens-wearing eyes (BE: 2.5 ?? 0.7%; CRT 3.5 ?? 1.3%) immediately on eye opening. No significant changes were found in either central stromal keratocyte or endothelial cell densities in either OK or control groups over the study period. In conclusion, overnight OK lens wear induces significant reductions in myopia after the first night of lens wear associated with improvement in unaided VA. Overnight OK lens wear causes significant thinning in the central epithelium and significant mid-peripheral stromal thickening which results in flattening of the central cornea and steepening in the mid-periphery. Although there were no significant changes in central stromal keratocyte and endothelial cell densities, thinning of the central epithelial layer raises concerns regarding the safety of the procedure, especially with the alarming number of corneal infections reported recently in the literature.

Un des enjeux majeurs dans l'intégration de nouveaux systèmes de guerre électronique (GE) dans les avions d'armes est notamment la réduction de l'encombrement des antennes. En GE, La bande passante des antennes peut être de l'ordre de la décade et la fréquence basse peut être voisine de la centaine de MHz, ce qui rend l'intégration des antennes difficile voire impossible selon les cas. Les antennes de GE font habituellement appel à des antennes dites "indépendantes de la fréquence" placées au-dessus d'une cavité absorbante. La fabrication des matériaux absorbants est à ce jour encore "artisanale" et donc onéreuse. De plus, ces matériaux sont lourds et ils ne présentent pas les mêmes caractéristiques électriques d'une fabrication à l'autre. Les travaux présentés dans ce manuscrit sont dédiés à la réalisation d'antennes à très large bande passante de très faible épaisseur et sans absorbant. Nous avons proposé et validé une nouvelle structure basée sur les matériaux à bandes interdites électromagnétiques (BIE). Le nouveau dispositif permet de remplacer les matériaux absorbants, de réduire l'épaisseur des antennes large bande et de réduire les coûts de fabrication grâce à un procédé industriel de fabrication. La nouvelle structure présente contrairement à toutes les autres structures BIE l'avantage d'être ultra large bande et compacte (de l'ordre de 1/100ième de longueur d'onde d'épaisseur). Nous avons montré l'intérêt d'utiliser un tel dispositif pour réduire l'épaisseur et améliorer les performances des antennes planaires de forme et de polarisation quelconque.

<p>Many prey species are able to develop different morphological structures as defence against</p><p>for example predators. Some of these structures are induced only by individuals exposed to a</p><p>predator. This phenomenon is called phenotypic plasticity. In this paper we examine whether</p><p>cuticle thickness in Leucorrhinia dubia (Odonata) larvae differed between specimens caught</p><p>in fish containing lakes and fish-free lakes respectively. We measured the thickness of the</p><p>cuticle from four different parts of the larvae; profemur, pronotum, ninth segment sternite and</p><p>ninth segment tergite. Our results showed a significantly thicker exocuticle on profemur in</p><p>larvae with a head width bigger than 4.5 mm caught in lakes with fish. The smaller larvae</p><p>showed a tendency to have thinner exocuticle on profemur in presence of fish. We discuss the</p><p>probability that the differences in exocuticle thickness on profemur could be some kind of</p><p>trade-off situation. The results also showed a tendency among the large larvae; the large</p><p>individuals from lakes containing fish had a slightly thicker exocuticle on pronotum than the</p><p>bigger individuals from fish-free lakes.</p>

Tube bending is a widely used manufacturing process in the aerospace, automotive, and other industries. During tube bending, considerable in-plane distortion and thickness variation occurs. The thickness increases at the intrados (surface of tube in contact with the die) and it reduces at the extrados (outer surface of the tube). In some cases, when the bend die radius is small, wrinkling occurs at the intrados. In industry a mandrel is used to eliminate wrinkling and reduce distortion. However, in the case of a close bend die radius, use of a mandrel should be avoided as bending with the mandrel increases the thinning of the wall at the extrados, which is undesirable in the manufacturing operation. The present research focuses on additional loadings such as axial force and internal pressure which can be used to achieve better shape control and thickness distribution of the tube. Based on plasticity theories, an analytical model is developed to predict cross section distortion and thickness change of tubes under various loading conditions. Results from both the FEA and analytical model indicated that at the intrados the increase in thickness for bending with internal pressure and bending with combined axial pull and internal pressure was nearly the same. But in the case of bending with the combination of axial pull and internal pressure there was a significant reduction of thickness at the extrados. A parametric study was conducted for the case of bending with combined internal pressure and axial pull and it was seen that with proper selection of the pressure and axial pull wrinkling can be eliminated, thickness distribution around the tube can be optimized, and cross section distortion of the tube can be reduced. Predictions of the analytical model are in good agreement with finite element simulations and published experimental results. The model can be used to evaluate tooling and process design in tube bending.

Many prey species are able to develop different morphological structures as defence against for example predators. Some of these structures are induced only by individuals exposed to a predator. This phenomenon is called phenotypic plasticity. In this paper we examine whether cuticle thickness in Leucorrhinia dubia (Odonata) larvae differed between specimens caught in fish containing lakes and fish-free lakes respectively. We measured the thickness of the cuticle from four different parts of the larvae; profemur, pronotum, ninth segment sternite and ninth segment tergite. Our results showed a significantly thicker exocuticle on profemur in larvae with a head width bigger than 4.5 mm caught in lakes with fish. The smaller larvae showed a tendency to have thinner exocuticle on profemur in presence of fish. We discuss the probability that the differences in exocuticle thickness on profemur could be some kind of trade-off situation. The results also showed a tendency among the large larvae; the large individuals from lakes containing fish had a slightly thicker exocuticle on pronotum than the bigger individuals from fish-free lakes.

This thesis describes a fundamental study of the miscibility and the nature of the interface between components of core-shell polymer blends using the technique of Fluorescence Resonance Energy Transfer (FRET) coupled with data analysis that involves Monte-Carlo simulations. Our aim in this study was to develop a fundamental methodology to quantitatively determine the width of the interface between the two components in binary polymer blends. At the current state of the art, data analysis of FRET experiments requires translational symmetry. In the system under study, uniform core-shell structures satisfy this criterion. Thus, in this work our focus was directed toward the study of a blend system with a core-shell structure. For this FRET study, I have identified a number of potential donor and acceptor dye pairs that fluoresce in the visible range of the spectrum and can be chemically attached to polymers. Among them, I selected, as the donor and the acceptor, a pair of naphthalimide dyes that have not previously been used for FRET experiments. Model experiments showed that while the fluorescence decay profile of the donor chromophore was exponential in solution, it was not exponential in polystyrene (PS) or poly(methyl methacrylate) (PMMA) films. Thus, I carried out refinements to existing FRET theory to interpret the data generated by using these dyes. Also, I derived a new model to predict the fluorescence intensity of non-exponential decaying donor dyes in core-shell systems. I selected a model system composed of a PS core surrounded by a PMMA shell. The PS core particles were prepared by miniemulsion polymerization to obtain cross-linked PS particles with a narrow size distribution. Seeded emulsion polymerization under starved-fed condition was employed to synthesize monodisperse dye-labeled core-shell particles. The extent of miscibility and the nature of interface between the core and the shell polymers were retrieved from a combined study by Monte-Carlo simulations and analysis of the donor fluorescence intensity decays. Agreement between the retrieved interface thickness and the literature data on PS-PMMA validates the methodology developed here for the use of such donor dyes in FRET studies on polymer blends.