The problem of tracking radar targets in the low-angle region Where conventional monopulse radars face difficulties due to the presence of multipath waves is considered in this thesis. The emphasis of the presentation is mainly directed towards finding a new simple closed-form solution to the coherent multipath problem over a smooth surface. Another concern is to improve the performance of the three-subapertures maximum-likelihood estimator when the two received signals are in-phase or anti-phase at the centre of the array. The multipath phenomenon and its modelling for smooth and rough surfaces are discussed and simulation results obtained for different surfaces. subsequently the following are treated First. a new four-subapertures technique to improve the in-phase and anti-phase performance of the maximum likelihood estimator above is derived and simulation results are shown. Then. an improved version of this technique is introduced as a part of the new algorithm. Second. a new three-subapertures trigonometric solution to solve the coherent multipath problem is derived and demonstrated by simulation results. This new method is simpler than the maximum likelihood estimator above and very similar in its estimation accuracy. Third. the performance of the maximum entropy method is tested for the coherent multipath problem by using the three-subapertures arrangement of a linear array. Finally the performances of the above three methods and the normal phase monopulse radar are tested and compared to different surfaces when the coherent and noncoherent multipath exist together. Simulation results show that the performances of the maximum entropy method and phase monopulse are much better than the others when the target is low-tlyine over a rough surface.

This dissertation investigates the crustal structure of the eastern Basin and Range Province in the western United States and its relationship with the present-day extensional regime governing this region. The use of combined results from different geophysical methods provide a better understanding of the subsurface crustal structure and the processes involved in this extensional deformation. Teleseismic receiver functions were used to create a uniformly sampled map of the crustal thickness variations and stacked images of the crust beneath the majority of the state of Utah, which provide additional constraints on the seismic characteristics of the crust and upper mantle. These results reveal crustal variations characterized by a distinct change in crustal thickness that closely follows the surface trace of the Wasatch fault, with differences in depth of up to 10 km across a distance of less than 55 km. Analysis of seismic reflection profiles, horizontal and vertical crustal velocities from continuous GPS, and surface geology provide new constraints on the relationships between interseismic strain accumulation, subsurface fault geometry, and geologic slip rates on seismogenic faults. Seismic reflection data show recent activity along high-angle normal faults that become listric with depth, sole into preexisting décollements, reactivating them, and appear to be connected at depth with a regionally extensive detachment horizon. GPS data reveal present-day crustal extension of ~3 mm/yr and no net vertical motion between the Colorado Plateau and eastern Basin and Range. Inverse modeling results of the crustal deformation data include a low-angle dislocation (~8-20°) at a locking depth of ~7-10 km, consistent with the interpreted seismic data, and slipping at 3.2±0.2 mm/yr, suggesting an active regionally extensive sub-horizontal surface beneath the eastern Basin and Range. A test of this hypothesis using seismic data interpretation as the basis for a forward strain accumulation model shows that displacement across a deep low-angle detachment imaged seismically is also consistent with geodetic velocities. Seismic and geodetic data support a model for eastern Basin and Range mechanics wherein diffuse permanent strain of the upper crust by multiple discrete faults is facilitated by displacement along a single low-angle detachment at midcrustal depth.

Geologic mapping, basin analysis, and tephrochronologic analysis in the Clifton quadrangle of southeast Idaho indicates that the modern Basin-and-Range topography is only a few million years old and that the bulk of Cenozoic extension was accommodated by slip on an older low-angle normal-fault system, the Bannock detachment system. The detachment system was active between ~12 and < 4 Ma and accommodated ~50 % extension. Cross-cutting relationships show that the master detachment fault, the Clifton fault, is the youngest low-angle normal fault of the system, was active at a low angle, and has not been rotated to a low-dip angle through time. Map patterns and relationships indicate that the hanging wall to the detachment system began as a cohesive block that later broke up along listric and planar normal faults that either sole into or are cut by the master detachment fault. The Miocene-Pliocene Salt Lake Formation, a syntectonic, basin-fill deposit of the Bannock detachment system, was deposited during three sub-episodes of extension on the detachment system. Depositional systems within the Salt Lake Formation evolved from saline/alkaline lakes to fresh water lakes and streams to braided streams in response to the changing structural configuration of rift basins in the hanging wall of the detachment system. After breakup of the hanging wall began, the master detachment fault excised part of the hanging wall and cut hanging-wall deposits and structures. The structural geometry of the Bannock detachment system strongly resembles that of detachments documented in metamorphic core complexes. Therefore, we interpret the Bannock detachment system as a proto-metamorphic core complex, akin to the Sevier Desert detachment fault. The Bannock detachment system also collapsed the Cache-Pocatello culmination of the dormant Sevier fold-and-thrust belt, much like the Sevier Desert detachment collapsed the Sevier culmination. Structures of the Bannock detachment system are overprinted by a second episode of extension accommodated by E- and NE-trending normal faults that may be related to subsidence along the Yellowstone hotspot track and a third episode of extension accommodated by high-angle, Basin-and-Range normal faults. This last episode of extension began no earlier than 4-5 Ma and continues today.

Kinematic analysis and field mapping of the Homestake shear zone (HSZ) and Slide Lake shear zone (SLSZ) in central Colorado provide new evidence for strain partitioning in the mid-crust at ~1.4 Ga. The northeast-striking, steeply dipping HSZ comprises a ~10-km-wide set of anastomosing ductile shear zones and pseudotachylyte-bearing faults. Approximately 3-km south of the HSZ, the north-northeast-striking, shallowly dipping mylonites of the SLSZ form three 1-10-m-thick shear zone splays. Both top-up-to-the-northwest and top-down-to-the-southeast shear sense are recorded in the SLSZ and HSZ. Oblique stretching lineations in both shear zones show vertical (top-down-to-the-southeast and top-up-to-the-northwest) and dextral movement occurred during mylonite development. Quartz and feldspar deformation mechanisms and quartz [c] axis lattice preferred orientation (LPO) patterns are consistent with deformation temperatures ranging from ~280-500°C in the HSZ to ~280-600°C in the SLSZ. Mean kinematic vorticity and quartz [c] axis LPOs for parts of each shear zone suggest plane and non-plane strain general shear with contributions of 47-69% pure shear and 31-53% simple shear. Based on micro- and mesoscale kinematics along with mean kinematic vorticity values and deformation temperature estimates, we propose that HSZ and SLSZ formed during strain localization and partitioning within a mid-crustal transpressional shear zone system that involved subvertical shuffling at ~1.4 Ga.

Ground based radars often experience difficulties in target detection and direction finding (DF) applications due to the interference between the direct and surface reflected signals when the targets fly at low altitudes. In this thesis, the phenomena governing the low angle propagation are overviewed and a multipath signal model including the effects of refraction, specular reflection, diffuse reflection, curvature of the earth and antenna polarization is presented. Then, the model is utilized to develop detection and DF algorithms for the targets at low altitudes. The target detection algorithm aims to increase signal-to-noise ratio (SNR) to overcome the effects of signal fading caused by surface reflections. The algorithm is based on diversity combining and the combining weight vector is calculated by maximizing average value of SNR. The technique is compared with Maximum Ratio Combining (MRC) algorithm which is optimal in terms of SNR. In direction finding, it is the height of the target that is explored since the target range information is obtained from the time delay. The target height is estimated by utilizing Maximum Likelihood Estimation (MLE). The performance of our algorithm is compared with that of the technique that is known in the literature as Refined Maximum Likelihood (RML).

Orientador: Iscia Teresinha Lopes Cendes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-19T22:29:20Z (GMT). No. of bitstreams: 1 Santos_KalincaPatriciaMarengo_D.pdf: 1191675 bytes, checksum: 8cf648c2f6c8894384e853d9dd28cde2 (MD5) Previous issue date: 2012 / Resumo: A análise molecular de proteínas é um componente crítico para o entendimento da molécula como um todo e de suas interações com outras moléculas nos mecanismos celulares. O papel de uma proteína no contexto celular fornece informações fundamentais para o entendimento de mecanismos biológicos causadores de muitas doenças hereditárias, cujas formas de tratamento ou cura são desconhecidas. Para que estas causas sejam elucidadas é necessário o entendimento dos processos de funcionamento das células, que em ultima análise depende essencialmente da descoberta das interações proteína-proteína no ambiente celular. Dentro deste contexto, é grande o interesse nas proteínas envolvidas nos mecanismos causadores de uma classe de doenças neurodegenerativas hereditárias por repetições de poliglutaminas (poliQ), as ataxias espinocerebelares (SCAs). Dentre elas nosso interesse recaiu sobre a proteína relacionada à doença ataxia espinocerebelar do tipo1 (SCA1). A mutação responsável pela SCA1 foi atribuída a expansões instáveis de poliQ localizadas na região codificadora do gene ATX1 que codifica uma proteína, a ataxina 1. A ataxina 1 apresenta entre 782-869 aminoácidos dependendo do número de glutaminas, tem massa molecular de aproximadamente 100 kDa, e é normalmente uma proteína predominantemente citoplasmática. No entanto, nos estados patológicos ela parece agregarse no núcleo dos neurônios de pacientes com a SCA1 (Paulson et al., 1997). O papel exato da proteína ataxina 1 normal ainda é desconhecido, embora evidências sugiram que sua função possa estar ligada a fatores de transcrição (Tsai et al., 2004). O mesmo acontece com o único domínio identificado e caracterizado na ataxina denominado AXH (De Chiara et al., 2005), que exibe uma similaridade significativa com a proteína HBP1 que age como ativador da transcrição para diversos genes (Levender et al., 1997; Tevosian et al., 1997). Neste estudo, o objetivo principal foi expressar e purificar o domínio AXH da proteína ataxina 1 e fragmento com poliQ nas formas normal e mutada, a fim de caracterizar essas regiões quanto às suas propriedades moleculares através da aplicação de técnicas de dicroísmo circular e raios-X de baixo ângulo / Abstract: Molecular analysis of proteins is a critical component to understanding the molecule as a whole and its interactions with other molecules in cellular mechanisms. The role of a protein in the cellular context provides information essential to understanding the biological mechanisms that cause many inherited diseases whose treatment or cure are unknown. For these causes are elucidated it is necessary to understanding the processes of cell function, which ultimately depends essentially on the discovery of protein-protein interactions in cellular environment. Within this context, it is great interest in the proteins involved in the mechanisms causing a class of hereditary neurodegenerative diseases by repeats of polyglutamine (poliQ), the spinocerebellar ataxias (SCAs). Among them our interest fell on the protein related to the disease spinocerebellar ataxia type 1 (SCA1). The mutation responsible for SCA1 was attributed to unstable expansions of poliQ located in the coding region of ATX1 gene that encodes a protein ataxin 1. Ataxin- 1 shows between 782-869 amino acids depending on the number of glutamine, has a molecular mass of approximately 100 kDa, and is usually a predominantly cytoplasmic protein. However, in pathological states it seems to aggregate in the nucleus of neurons of patients with SCA1 (Paulson et al., 1997). The exact role of the protein ataxin-1 standard is still unknown, although evidence suggests that its function may be linked to transcription factors (Tsai et al., 2004). The same applies to the only area identified and characterized in ataxin named AXH (De Chiara et al., 2005), which displays a significant similarity to HBP1 protein that acts as an activator of transcription for several genes (Levender et al., 1997; Tevosian et al., 1997). In this study, the main objective is to express and purify the AXH domain of ataxin-1 protein in normal and mutated forms in order to characterize this region in terms of some of its molecular properties with the application of the techniques of circular dichroism and X-rays of low angle / Doutorado / Ciencias Biomedicas / Doutor em Ciências Médicas

No description available.

Mid-Tertiary metamorphic core complexes in the Basin and Range province of the western North American Cordillera are characterized by large-magnitude extensional deformation. Numerous models have been proposed for the kinematic evolution of these metamorphic core complexes. Such models generally invoke footwall isotatic rebound due to tectonic denudation, and the presence of a weak middle crust capable of flow at mid-crustal levels. In popular models of Cordilleran-style metamorphic core-complex development, initial extension occurs along a breakaway fault, which subsequently is deformed into a synform and abandoned in response to isostatic rebound, with new faults breaking forward in the dominant transport direction. In southeast Arizona, the Catalina and Pinaleño Mountains core complexes have been pointed to as type examples of this model. In this study, the “traditional” core-complex model is tested through analysis of field relations and geochronological age constraints, and by interpretation of seismic reflection profiles along a transect incorporating these core complexes. Elements of these linked core-complex systems, from southwest to northeast, include the Tucson Basin, the Santa Catalina-Rincon Mountains, the San Pedro trough, the Galiuro Mountains, the Sulphur Springs Valley, the Pinaleño Mountains, and the Safford Basin. A new digital compilation of geological data, across highly extended terranes, in conjunction with reprocessing and interpretation of a suite of industry 2-D seismic reflection profiles spanning nearly sub-parallel to regional extension, illuminate subsurface structural features related to Cenozoic crustal extension and provide new constraints on evolution of core complexes in southeast Arizona. The main objective is to develop a new kinematic model for mid-Tertiary extension and core complex evolution in southeast Arizona that incorporates new geological and geophysical observations. Geological and seismological data indicate that viable alternative models explain observations at least as well as previous core-complex models. In contrast to the “traditional” model often employed for these structures, our models suggest that the southwest- and northeast-dipping normal-fault systems on the flanks of the Galiuro Mountains extend to mid-crustal depths beneath the San Pedro trough and Sulphur-Springs Valley, respectively. In our interpretations and models, these oppositely vergent fault systems are not the breakaway faults for the Catalina and Pinaleño detachment systems.

Precambrian metamorphic rocks in the Beaver Dam Mountains display asymmetric, isoclinal folds with consistent fold axes plunging to the NW. These folds are parasitic and have a recursive nature that occurs on wavelengths from centimeters to perhaps kilometers as part of a NW-SE striking shear zone. The vergence of the folds indicates oblique shearing with a transport direction plunging 29° to the south. This shear zone may be associated with the collision of Yavapai Province island arcs with Laurentia. Structurally overlying, and adjacent to the metamorphic rocks are allochthonous and attenuated Mississippian limestone blocks and other strata debated to be either the result of mega-landsliding or fragments of the hanging wall rocks above a low-angle normal fault. We document previously unreported cataclastic damage zones tens of meters thick, an anastomosing zone of greenschist facies alteration hundreds of meters thick, and polished low-angle fault surfaces beneath these blocks. Other observations previously used to support a mega-landslide hypothesis are blocks of Redwall Limestone structurally overlying what was interpreted as Tertiary conglomerate. However, this contact is depositional, and the conglomerate is likely a sedimentary breccia facies of the Mississippian Redwall Limestone which is documented in several locations within the region. Additionally, some of the deformation and attenuation that was wrongly attributed to mega-landsliding or low-angle normal faulting is due to previously undocumented soft-sediment deformation. This deformation was gravity driven and accommodated by ductile granular flow, resulting in recumbent folds within the Mississippian Redwall Limestone and a prominent non-brittle detachment surface between the Redwall Limestone and the Cambrian Bonanza King Formation at Castle Cliff. This detachment was previously interpreted as the Castle Cliff Detachment, a low-angle normal fault, or as the slip surface of a landslide.

Lisozima mostrou-se capaz, quando dispersa em certos meios orgânico-aquosos, de gerar sistemas pseudoplásticos que evoluem espontaneamente para redes de caráter viscoelástico. Esse fenômeno foi investigado neste estudo, para lisozima dispersa em uma série de misturas binárias contendo derivados de uréia como componente orgânico. Devido aos notáveis efeitos observados para um de tais derivados, a saber, tetrametiluréia (TMU), especial atenção foi dedicada aos sistemas contendo esse composto. O enfoque experimental incluiu espectroscopia Raman, microcalorimetria, reologia e espalhamento de raios X a baixo ângulo (SAXS). O trabalho envolveu o estudo dos sistemas orgânico-aquosos isolados e na presença de proteína. No primeiro caso, foi feita uma investigação espectroscópica e microcalorimétrica dos sistemas quanto a aspectos relativos à segregação de microdomínios na fase liquida e sua conseqüente relação com a deflagração da transição viscoelástica na proteína. Foram observadas descontinuidades nos valores de entalpias de excesso de mistura para o sistema TMU/água em torno de wTMU = 0,6, assim como padrões peculiares de comportamento espectral em torno dessa concentração da mistura binária. No segundo caso, os sistemas complexos de proteínas gerados foram investigados sob o ponto de vista morfológico e dinâmico, através das técnicas reológicas e de SAXS. Energias de ativação de fluxo determinadas na região sub-crítica, de comportamento Newtoniano, mostraram uma dependência exponencial direta com wTMU, indicando que mudanças estruturais nos fluidos complexos já ocorrem em regiões de composição do solvente bem abaixo da região de transição em wTMU = 0,6. Na região viscoelástica, 0,6<wTMU<0,9, ensaios de relaxação indicaram a presença de duas populações distintas. A tangente de perda (tg &#948; = G\"/G\') apresentou valores menores que a unidade para todos os casos, indicando o caráter \"solid-like\" das redes nas condições de ensaio. Apesar de seu caráter sólido, as redes mostram-se bastante flexíveis, suportando grandes deformações antes da ruptura, como inferido a partir da larga região viscoelástica linear. A variação nos módulos elástico (G\') e de perda (G\") com a composição do solvente indica a dependência do caráter viscoelástico com a fração de massa de TMU na mistura binária. Na região de baixo conteúdo de água (wTMU = 0,9), um aumento em G\" após a região viscoelástica linear é observado, indicando aumento da estruturação antes da ruptura da rede. As curvas de SAXS foram modeladas em seus fatores de forma e de interferência com uma equação unificada para objetos aleatoriamente distribuídos em um continuum. Os resultados permitiram a construção de um modelo, compatível com as demais evidências experimentais, segundo o qual as moléculas de lisozima encontram-se em duas conformações distintas nas matrizes: uma de conformação estendida e caráter fractal, predominante em wTMU > 0,6, com dimensão máxima de ca. de 160 &#197;, responsável pela interdigitação com espécies fractais vizinhas e uma espécie compacta, minoritária em wTMU > 0,6 (porém predominante em wTMU <0,6), com raio de giro de ca. 48 &#197;, presente nos microdomínios intersticiais aquosos da matriz. Verificou-se ainda a viabilidade de incorporação homogênea de uma metaloproteína, o citocromo-c, às matrizes de lisozima, sem perturbação significativa de sua morfologia, o que constitue um evento de potencial interesse biotecnológico. Os resultados deste trabalho trazem novos suportes experimentais à hipótese de correlação entre inversão na microconfiguração do meio solvente binário e deflagração do processo de transição sol-gel da proteína. / Lysozyme was found to be able, when dispersed in certain organic/aqueous media, to generate pseudoplastic systems that spontaneously evolve to three-dimensional networks with viscoelastic character. This phenomenon was investigated in this study, for lysozyme dispersed in a series of binary mixtures containing urea derivatives as the organic component. Due to the remarkable effects obtained in one of such derivatives, namely, tetramethylurea (TMU), special attention was given to systems containing that compound. The experimental approach included Raman spectroscopy, microcalorimetry, rheology and small angle X ray scattering (SAXS). The work involved the study of the organic/aqueous systems on their own and in the presence of protein. The former consisted of binary liquid mixtures that were spectroscopically and microcalorimetrically investigated as to aspects concerning microdomain segregation in the liquid phase and its consequent relationship with the threshold of the protein viscoelastic transition. Discontinuities in the excess enthalpy of mixture were observed for TMU/water system around wTMU=0.6, as well as peculiar spectral patterns around that same binary mixture concentration. The latter comprised complex protein systems that were investigated both under a morphological and dynamical point of view. Flow activation energies determined in the sub-critical (Newtonian) region showed an exponential increase with wTMU, indicating that structural changes in the comp]ex fluids are under way at solvent concentration regions well below that of the transition, at wTMU = 0.6. In the viscoelastic region, 0.6<wTMU<0.9, relaxation studies indicated the presence of two distinct populations. The loss tangent (tan &#948; = G\"/G\') presented values lower than the unity for all cases, indicating the solid-like character of the matrices, in the assay conditions. Despite their solid character the networks are quite flexible, standing large strains before rupture, as inferred from the large linear viscoelastic region. The variation in elastic (G\') and loss (G\") moduli with solvent composition indicates a dependence of the viscoelastic character on TMU mass fraction in the binary mixture. In the region of low water content (wTMU = 0.9), an increase in G\" after the LVR is observed, indicating increase in network structuring before rupture. SAXS curves were modeled with a unified equation for randomly distributed objects in a continuum. Results allowed the proposal of a model, which is compatible with the experimental evidence obtained through the other techniques in this work, according to which lysozyme molecules occur in two distinct conformations: one expanded and with fractal character, prevailing at wTMU > 0.6, with maximum dimension ca. 160 &#197; and interdigitated with neighbouring fractal species; and a compact conformation, of minor prevalence at wTMU>0.6 (but prevailing at wTMU < 0.6), with radius of gyration ca. 48 &#197;, present in the matrix microdomain interstices. It has also been verified the feasibility of homogeneous incorporation of cytochrome-c into the lysozyme matrices, an event of potential biotechnological interest. Results from this work bring further experimental support to our hypothesis on the correlation between microconfigurational inversion in the binary solvent medium and the sol-gel transition in the protein.