In this thesis, multidimensional signal processing techniques to mitigate disturbances in synthetic aperture systems such as radio telescopes are investigated. Here, two computationally efficient three-dimensional (3D) spatio-temporal (ST) finite impulse response (FIR) cone filter bank structures are proposed. Furthermore, a strategy is proposed to design 3D ST FIR frustum filter banks, having double-frustum-shaped passbands oriented along the temporal axis, derived from appropriate 3D ST FIR cone filter banks. Both types of cone and frustum filter banks are almost alias free and provide near-perfect reconstruction. In the proposed cone and frustum filter banks, both temporal and spatial filtering operations can be carried out at a significantly lower rate compared to previously reported 3D ST FIR cone filter banks implying lower power consumption. Furthermore, the proposed cone and frustum filter banks require a significantly lower computational complexity than previously reported 3D ST FIR cone and frustum filter banks. Importantly, this is achieved without deteriorating the improvement in signal-to-interference-plus-noise ratio. A theoretical analysis of brightness distribution (BD) errors caused by parameter perturbations and mismatches among the transfer functions of receivers employed in synthetic aperture systems is presented. First, the BD errors caused by perturbations in the transfer functions of low noise amplifiers (LNAs) and anti-aliasing filters (AAFs) are considered, and the characteristics of the additive BD error and its effects on synthesized BDs are thoroughly analyzed. Second, the conditions that should be satisfied by the transfer functions of digital beamformers to eliminate the BD errors caused by their phase responses are examined. The sufficient condition to eliminate the BD errors is that the transfer functions are matched, and, interestingly, the phase responses are not necessary to be linear. Furthermore, the BD errors caused by typical tolerances of passive L and C elements used to implement the AAFs and those caused by the random variations of gain from LNA to LNA are quantified through numerical simulations. The simulations indicate that substantial BD errors are observed at frequencies that are close to the passband edge of the AAFs. / Graduate

Thesis (M.S.)--Ohio University, June, 2003. / Title from PDF t.p. Includes bibliographical references (leaves 102-108).

Thesis (M.S.) -- University of Tennessee, Knoxville, 2005. / Title from title page screen (viewed on Feb. 2, 2006). Thesis advisor: Marianne Breinig. Vita. Includes bibliographical references.

The following study was implemented in order to evaluate the effects of different shading levels on the growth and development of Aloysia triphylla plant and the production of essential oil in the four seasons of the year. The experiment was conducted at the Federal University of Santa Maria Campus of Frederico Westphalen, from August 2011 to December 2012. The experimental design was a randomized block design in a factorial scheme with three shading levels (0%, 30% and 50%) and four seasons of the year (summer, autumn, winter and spring). For growth analysis, plants were collected every fortnight. The essential oil was extracted from fresh plant material by steam distillation process, using the modified Clevenger apparatus at the end of each season. For all analyzed variables, it was observed higher growth, production, yield and essential oil content in the season of summer, followed by spring, showing that, in these seasons, the cultivation of Aloysia triphylla may be possible in environments with 30% and 50% shading. Autumn and winter showed low plant growth and essential oil production, and shading decreased further the increase and plant yield. / O presente trabalho foi implantado com o objetivo de avaliar os efeitos de diferentes níveis de sombreamento sobre o crescimento de planta de Aloysia triphylla e a produção de óleo essencial nas quatro estações do ano. O experimento foi instalado na Universidade Federal de Santa Maria - Campus de Frederico Westphalen, de agosto de 2011 a dezembro de 2012. O delineamento experimental utilizado foi de blocos casualizados, em esquema bifatorial com três níveis de sombreamento (0%, 30% e 50%) e quatro estações do ano (verão, outono, inverno e primavera). Para análise de crescimento foi realizada coleta quinzenal de plantas e para extração do óleo essencial foi utilizado material fresco, utilizando-se aparelho Clevenger modificado. Para todas as variáveis analisadas observou-se maior crescimento, produção, rendimento e teor de óleo essencial na estação do verão, seguido pela primavera, podendo, nestas estações ser realizado o cultivo da Aloysia triphylla em ambientes com 30% e 50% de sombreamento. O outono e inverno apresentaram baixo crescimento de planta e produção de óleo essencial e o sombreamento diminuiu ainda mais o incremento e rendimento da planta.

The aim of this work has been to increase our understanding of the surface brightness distributions of late-type stars through Doppler imaging and eclipse mapping techniques. Combining spectroscopic and photometric observations with the technique of Doppler Imaging, I have reconstructed surface images of the G2V star He 699 (for 08 October 2000), which show high latitude and polar structures. In the case of the KOV star AB Dor, the Doppler images for January 1992 and November 1993 show a large polar cap with small dark features also present at intermediate to high latitudes. As the phase sampling of the observations was insufficient to apply the sheared-image method it was not possible to detect any differential rotation. In the second part of my thesis I determine the surface brightness distribution of the primary component of the RS CVn eclipsing binary SV Cam. I have used extrapolated size distributions of sunspots to an active star to synthesize images of stellar photospheres with high spot filling factors. The resulting surface images, reconstructed with the Maximum Entropy eclipse mapping technique, show large spurious spot features at the quadrature points. It is concluded that two-spot modelling or chi-squared minimisation techniques are more susceptible to spurious structures being generated by systematic errors, arising from incorrect assumptions about photospheric surface brightness, than simple Fourier analysis of the light-curves. Spectrophotometric data from 9 HST orbits, observed in November 2001, have been used to eclipse-map the primary component of SV Cam. In combination with its HIPPAR- COS parallax it is found that the surface flux in the eclipsed low-latitude region is about 30% lower than computed from the best fitting PHOENIX model atmosphere. This flux deficit can only be accounted for if about a third of the primary's surface is covered with unresolved spots. However, when the spottedness from the eclipsed region is applied to the entire surface of the primary star, there still remains an unaccounted flux deficit. The remaining flux deficit is explained by the presence of a large polar spot extending down to latitude 48+/-6 deg. When the Maximum Entropy eclipse mapping technique is used to fit SV Cam's lightcurve, the observed minus computed residuals show strong spurious peaks at the quadrature points. It is only possible to reduce these peaks with the addition of a polar cap and the reduction of the primary star's temperature, to account for the star being peppered with unresolvable spots. Motivated by this result we investigate the limb darkening of the primary component of SV Cam. The wavelength dependence of the limb darkening is analysed by sub-dividing the HST lightcurve into 10 bands of equal emission flux. Flux variations between the first and fourth contact of the primary eclipse indicate that the limb darkening decreases towards longer wavelengths, in accordance with published limb darkening laws. Comparing fits of ATLAS and PHOENIX model atmospheres we find a wavelength dependence of the best fitting model. Due to its smooth cutoff at the stellar limb, the spherical geometry of the PHOENIX model atmosphere gives the best fit during partial eclipse. Between the second and third contact the difference between spherical and plane-parallel geometry is less important.

abstract: ABSTRACT 1. Aposematic signals advertise prey distastefulness or metabolic unprofitability to potential predators and have evolved independently in many prey groups over the course of evolutionary history as a means of protection from predation. Most aposematic signals investigated to date exhibit highly chromatic patterning; however, relatives in these toxic groups with patterns of very low chroma have been largely overlooked. 2. We propose that bright displays with low chroma arose in toxic prey species because they were more effective at deterring predation than were their chromatic counterparts, especially when viewed in relatively low light environments such as forest understories. 3. We analyzed the reflectance and radiance of color patches on the wings of 90 tropical butterfly species that belong to groups with documented toxicity that vary in their habitat preferences to test this prediction: Warning signal chroma and perceived chromaticity are expected to be higher and brightness lower in species that fly in open environments when compared to those that fly in forested environments. 4. Analyses of the reflectance and radiance of warning color patches and predator visual modeling support this prediction. Moreover, phylogenetic tests, which correct for statistical non-independence due to phylogenetic relatedness of test species, also support the hypothesis of an evolutionary correlation between perceived chromaticity of aposematic signals and the flight habits of the butterflies that exhibit these signals. / Dissertation/Thesis / M.S. Biology 2013

No description available.

Monomeric red fluorescent proteins (RFPs) are used extensively for applications in molecular biology research, and are especially suited for whole body imaging applications due to their longer excitation and emission wavelengths, which are less damaging and penetrate deeper into animal tissue. However, these proteins suffer from reduced brightness compared to other fluorescent proteins, and require further engineering, which is often achieved through random methods, incurring large time and resource costs. Here we propose a rational design approach to improve the quantum yield of RFPs by reducing conformational variability of the chromophore. We engineered mRojoA, a mutant containing a π-stack involving Tyr197 and the chromophore phenolate, to include the P63F/H/Y mutations on its other side, by simultaneously mutating neighbouring positions 16, 143, and 163. The brightest mutants that we found in each library, mRojo-VYGV, mRojo-VFAV, and mRojo-VHSV, exhibited 1.8- to 2.4-fold increases in brightness, and quantum yield increases of up to 2.1-fold. In all three mutants, the increases in brightness were predominantly due to improvements in the quantum yield and not the extinction coefficient. Solving the crystal structures of two of these mutants along with a dim variant allowed us to strongly infer a link between rigidity of the chromophore and increased quantum yield. In addition, back-mutating position 63 in the highest quantum yield mutant, mRojo-VYGV, reversed the improvement in quantum yield, indicating that Y63 was the primary residue responsible for the improved brightness of the protein. Unfortunately, the mCherry-VYGV mutant did not achieve a similar increase in quantum yield or brightness. This is likely due to the lack of a second bulky aromatic residue at position 197, which is present in mRojoA. Nevertheless, this rational approach could be applied to some other RFPs whose chromophores exhibit increased conformational variability in order to further improve their brightness.

A produção de biocombustíveis a partir das microalgas vem se tornando promissora por ser uma fonte renovável, não poluente e por não competir com áreas de cultivo de alimentos. Devido à exaustão das fontes fósseis e à alta demanda por combustível de origem renovável e não poluente, as microalgas vêm despertando interesse nos cenários energético e ambiental. Por outro lado, existe um elevado custo no cultivo das mesmas, fazendo-se necessário estudos para desenvolvimento de novos reatores, meios de cultivos, técnicas de colheita, de extração de lipídios, transesterificação e também a implementação do conceito de biorrefinaria. Levando em conta o interesse crescente na utilização das microalgas como matéria prima na produção de biocombustíveis e a necessidade de estudos que torne o cultivo das microalgas em grande escala economicamente viável, esta pesquisa teve como objetivo determinar as melhores condições para o cultivo da microalga Chlorella vulgaris, buscando uma maior produtividade de biomassa e de lipídios. Os fatores avaliados foram: tempo de luminosidade, reciclo da biomassa após extração de lipídios e concentração de nutrientes (NaNO3, K2HPO4, KH2PO4 e glicerol) no meio de cultivo, em um arranjo ortogonal de Taguchi L8. De acordo com os resultados, identificou-se uma maior relevância, para a produtividade de biomassa, a utilização de glicerol e luminosidade (12 h), seguido do NaNO3 em alta concentração. A utilização de biomassa extraída mostrou-se inviável para o processo de cultivo, e a utilização de K2HPO4, KH2PO4 foram pouco influentes, porém essenciais. Paralelamente foi avaliado a viabilidade em se utilizar o efluente da Estação de Tratamento de Esgoto (ETE) da Escola de Engenharia de Lorena (EEL-USP) como meio de cultivo em um reator de PVC, construído para cultivo heterotrófico, no qual obteve-se uma alta produtividade de biomassa (0,20 g.L-1.d-1) e de lipídios (83,35 mg.L-1.d-1), se comparados a outros processos. / The production of biofuels from microalgae has become promising because it is a renewable, non-polluting source and because it does not compete with food growing areas. Due to the exhaustion of fossil fuel sources and the high demand of fuel from renewable and non-polluting origin, microalgae have been attracting interest in the energy and environmental scenarios. On the other hand, there is a high cost to cultivate microalgae, making necessary studies for the development of new reactors, culture media, harvesting techniques, lipid extraction, transesterification and also the implementation of the biorefinery concept. Taking the growing interest in the use of microalgae as a raw material in the production of biofuels and the need of studies to make large-scale microalgae cultivation economically viable, this research aimed to determination of the best conditions for the cultivation of microalga Chlorella vulgaris, seeking a higher productivity of biomass and lipids. The factors evaluated were: time of luminosity, biomass recycling after lipid extraction and nutrient concentration (NaNO3, K2HPO4, KH2PO4 and glycerol) in the culture medium using a orthogonal arrangement of Taguchi L8. According to the results, a greater relevance was identified for biomass productivity, the use of glycerol and luminosity (12 h), followed by NaNO3 in high concentration. The use of extracted biomass proved to be impractical for the process, and the use of K2HPO4, KH2PO4 was weak but essential. In parallel, the feasibility of using the effluent of the Effluent Treatment Plant (ETP) on Escola de Engenharia de Lorena (EEL-USP) as a culture medium for a PVC reactor, built for heterotrophic cultivation. It was obtained higger productivity of biomass (0.20 g.L-1.d-1) and lipids (83.35 mg.L-1.d-1) from it, if you compare to others process.

With global warming on the rise and the urge for conserving our natural resources, it becomes very important that proper steps are taken to protect our natural resources and utilize them efficiently. Forest fires are one of the many issues on the charts towards protection of natural resources. The catastrophic aftermaths caused by forest fires are known to all. The causes for these fires could be known/unknown natural causes or human intervention. Remote sensing techniques use the electromagnetic radiation in the RF/Microwave region, emitted from an object. The amount of energy emitted from an object depends on its present conditions, primarily its temperature and its emissivity. The sensing devices used in such measurements are classified into active and passive sensors. Herein, passive radiometry is used to investigate a model for the propagation of subsurface radiation from underground forest fires through upper ground layers of soil till the land-air interface. Passive radiometry involves capturing the radiation incident on a radiometer antenna aperture directly or deflected from several objects. The energy emitted from sources above 0K is collected and is compared with the calibration standards to estimate the physical quantity under test. Detecting forest fires is one of the potential applications of passive radiometry investigated here.