1,190 research outputs found
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Life in the slip lane: the effect of molecular level friction on algal adhesion
The settlement and adhesion of Navicula perminuta and Ulva linza to methyl-terminated alkanethiol self-assembled monolayers (SAMs) of increasing chain length has been investigated. Organisms were allowed to settle onto the monolayers and were subsequently exposed to hydrodynamic shear stress in order to determine their adhesion strength. Results show that as the SAM structure changes from amorphous to crystalline (C14), there is a marked change in the adhesion of N. perminuta and U. linza. Given that the SAMs in the series all exhibit similar contact angle behaviour and surface energy, it is hypothesized that the lubricity of the surface plays a role in determining the surface adhesion
Evaluation of the water use efficiency of dairy production using crops and pastures
This study evaluated the water use efficiency (WUE) of milk and forage production from a range of temperate and tropical forages on 5 dairy farmlets and a small field plot study located at Mutdapilly Research Station in south east Queensland. The feedbase had a greater affect on the WUE of milk production than the volume of irrigation and rainfall received. For instance, the high irrigation, high quality temperate pasture based (M4) farmlet received an additional 36% volume of water when compared to the crop based feedlot (M5) farmlet, though milk production from forage was 30% less. This difference in efficiency occurred in part from the superior WUE of the irrigated maize (Zea mays) summer crop with 3.4 t DM/ML and lucerne (Medicago sativa) winter crop with 2 t DM/ML, and the increased efficiency of herbage utilisation from the conservation of crops compared with grazing of pastures. The raingrown (M1) farmlet’s WUE of milk production was relatively high, however forage production was limited and consequently milk yield was comparatively low. The range in herbage WUE associated with forage species was consistent between the farmlet and small plot studies. Farmers are challenged with striking a balance between selecting forage types that optimise WUE and those that increase diet quality
Signal Processing for Synthetic Aperture Sonar Image Enhancement
This thesis contains a description of SAS processing algorithms, offering improvements in Fourier-based reconstruction, motion-compensation, and autofocus. Fourier-based image reconstruction is reviewed and improvements shown as the result of improved system modelling. A number of new algorithms based on the wavenumber algorithm for correcting second order effects are proposed. In addition, a new framework for describing multiple-receiver reconstruction in terms of the bistatic geometry is presented and is a useful aid to understanding. Motion-compensation techniques for allowing Fourier-based reconstruction in widebeam geometries suffering large-motion errors are discussed. A motion-compensation algorithm exploiting multiple receiver geometries is suggested and shown to provide substantial improvement in image quality. New motion compensation techniques for yaw correction using the wavenumber algorithm are discussed. A common framework for describing phase estimation is presented and techniques from a number of fields are reviewed within this framework. In addition a new proof is provided outlining the relationship between eigenvector-based autofocus phase estimation kernels and the phase-closure techniques used astronomical imaging. Micronavigation techniques are reviewed and extensions to the shear average single-receiver micronavigation technique result in a 3 - 4 fold performance improvement when operating on high-contrast images. The stripmap phase gradient autofocus (SPGA) algorithm is developed and extends spotlight SAR PGA to the wide-beam, wide-band stripmap geometries common in SAS imaging. SPGA supersedes traditional PGA-based stripmap autofocus algorithms such as mPGA and PCA - the relationships between SPGA and these algorithms is discussed. SPGA's operation is verified on simulated and field-collected data where it provides significant image improvement. SPGA with phase-curvature based estimation is shown and found to perform poorly compared with phase-gradient techniques. The operation of SPGA on data collected from Sydney Harbour is shown with SPGA able to improve resolution to near the diffraction-limit. Additional analysis of practical stripmap autofocus operation in presence of undersampling and space-invariant blurring is presented with significant comment regarding the difficulties inherent in autofocusing field-collected data. Field-collected data from trials in Sydney Harbour is presented along with associated autofocus results from a number of algorithms
Annotated Bibliography of Fire Literature Relative to Northern Grasslands in South-Central Canada and North-Central United States
This publication provides a condensed reference of fire literature for those with an interest in fire ecology
The interaction of marine fouling organisms with topography of varied scale and geometry: a review
Many studies have examined the effects of surface topography on the settlement behaviour of marine organisms and this article reviews these investigations with more emphasis on the effects of topography scale. It has been observed that macro topographies (1-100 mm) are generally favoured by marine fouling taxa and are unsuitable for antifouling applications. This is because macro topographies are usually large enough to fit fouling organisms and provide refuge from dangers in the marine environment. Micro topographies had only limited success at reducing fouling from a wide range of marine taxa. The antifouling performance of micro topographies (1 to ≤1000 μm) is dependent on the properties of topography features in terms of symmetry, isotropy, width, length, height/depth, separation distance and average roughness. In terms of the antifouling performance of micro topography, topography geometry may only be of secondary importance in comparison to the size of features itself. It is also noted that hydrodynamic stresses also contribute to the settlement trends of foulers on textured surfaces. Future studies on antifouling topographies should be directed to hierarchical topographies because the mixed topography scales might potentially reduce fouling by both micro and macro organisms. Patterned nano-topographies (1- ≤1000 nm) should also be explored because the antifouling mechanisms of these topographies are not yet clear
Annotated Bibliography of Fire Literature
Natural resource managers have greatly increased the use of fire to manage grassland habitats during the past two decades in the northern Great Plains region of the United States and Canada. In support of these efforts, we have compiled this annotated bibliography to provide a condensed reference of fire literature for those managers with an interest in fire ecology. References are arranged alphabetically by author and year, numbered consecutively, and referenced by number in the author and subject indexes that follow the bibliography. The intent in compiling the bibliography and indexes is more to identify subject matter and to direct the reader to sources rather than to provide a digested interpretation of each manuscript
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Research capacity building with mycetoma as the central research challenge
The Lancet Commission on the future of health in sub-Saharan Africa concluded that Africa's research transformation will only happen through investment, collaboration and partnerships. Here we describe the research capacity building partnership developed between the Mycetoma Research Centre in Khartoum, Sudan, and the Centre for Global Health Research at Brighton & Sussex Medical School (BSMS), Brighton, UK. This partnership, supported by the BSMS–National Institute for Health Research (NIHR) Global Health Research Unit (GHRU) on Neglected Tropical Diseases and the NIHR Research Innovation for Global Health (RIGHT)-funded Social Sciences for Severe Stigmatising Skin Conditions (5S) Foundation, uses the multidisciplinary, translational model originally used to study podoconiosis, another highly neglected tropical condition, and applies this to the conundrum that is mycetoma
Escola de Belas Artes e Indústrias do Paraná : o projeto de ensino de artes e ofícios de Antônio Mariano de Lima - Curitiba, 1886-1902
Orientadora: Serlei Maria Fischer RanziDissertação (mestrado) - Universidade Federal do Paraná, Setor de Educação, Programa de Pós-Graduação em Educação. Defesa: Curitiba, 2004Inclui bibliografi
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