David Richard Walker’s Metrology of the Roman Silver Coinage analyzed the silver content of over 5000 Roman denarii, antoniniani, and drachmae using x-ray fluorescence (XRF) spectrometry. His results have been widely cited and used by scholars in the fields of Roman economic theory and numismatics. This thesis seeks to prove that Walker’s XRF results were not only inaccurate, but inconsistently so. Corrosion and surface enrichment on silver-copper coins have caused surface-level elemental examinations, like XRF, to produce incorrect results. The results from Walker’s XRF analysis have been compared against results from four individual wet chemical studies. The comparisons display striking, and significant, differences. I am forced to conclude that Walker’s data does not in any way align with the true silver content of the coins he analyzed. As a result, this thesis will re-examine several theories and hypotheses posed by scholars who used Walker’s data and propose new, more appropriate, uses for Walker and XRF analysis outside of the examination of corroded silver-copper coins.

Considerando as várias propriedades fisiológicas e patológicas já descritas para os nucleotídeos da adenina, muitos estudos têm sugerido um importante papel destas moléculas no desenvolvimento de tumores. Enquanto o ATP parece ser citotóxico às células tumorais, a adenosina possui uma atividade tumorogênica. Além disso, muitos estudos demonstram o envolvimento dos nucleotídeos na modulação da resposta imune. As ações induzidas pela sinalização purinérgica são reguladas pelas nucleotidases, que podem estar localizadas nas membranas celulares ou podem apresentar-se de forma solúvel no meio intracelular e/ou extracelular. Pertencem a este grupo de enzimas a família das nucleosídeo trifosfato difosfoidrolase (NTPDases), a família das nucleotídeo pirofosfatase/fosfodiesterase (NPPs) e a 5’-nucleotidase. Muitos estudos sugerem que o uso de antiinflamatórios não-esteroidais está associado com a proteção contra o desenvolvimento de muitos tipos de câncer. Neste estudo, nós avaliamos a hidrólise extracelular dos nucleotídeos da adenina em linfócitos de ratos adultos submetidos ao modelo tumoral de Walker 256, bem como uma possível modulação do ácido acetilsalicílico (AAS) nas atividades nucleotidásicas em linfócitos e soro de ratos submetidos ao mesmo modelo. Nossos resultados demonstraram um aumento significativo nas hidrólises de ATP e ADP em linfócitos no décimo dia após a indução tumoral e/ou o tratamento com AAS. Nenhuma alteração na hidrólise do AMP foi observada. A administração de AAS aumentou a hidrólise de ATP e ADP em linfócitos de ratos inoculados com o tumor. Os níveis transcricionais das NTPDases1-3 foram significativamente aumentados na presença do tumor e diferentemente afetados pela administração do AAS. No soro, a hidrólise do ATP foi alterada pelo AAS apenas no décimo dia de tratamento, enquanto as hidrólises de ADP e AMP foram alteradas no sexto e no décimo dias. A administração de AAS aos animais inoculados com o tumor promoveu uma redução significativa nas hidrólises de ATP e AMP no sexto dia. A partir desses resultados, podemos concluir que a modulação dos níveis dos nucleotídeos em linfócitos pareceu não contribuir para os efeitos benéficos do AAS no câncer. Por outro lado, na circulação, um efeito potencialmente benéfico do AAS sobre o tumor foi observado no período inicial de tratamento. Assim, é possível sugerir, que o AAS possa desempenhar um importante papel na prevenção da invasão do tumor, parecendo não ser mais efetivo após sua instalação e desenvolvimento no hospedeiro. / In addition to the various physiological and pathological properties already known for adenine nucleotides, an important role of these molecules in tumor development has been proposed. Whereas ATP has been shown to be cytotoxic for tumoral cells, adenosine has been shown to posses a tumor-promoting action. Moreover, many studies have also demonstrated the nucleotide involvement in immune response modulation. The actions induced by purinergic signaling are regulated by nucleotidases, that are located on cell membrane or they are present in soluble forms on the intracellular and/or extracellular milieu. These enzymes comprise the nucleoside triphosphate diphosphohydrolase family (NTPDases), the nucleotide pyrophosphatase/ phosphodiesterase family (NPPs) and the 5’- nucleotidase. Numerous studies have suggested that the use of non-steroidal antiinflammatory drugs can protect against the development of cancer. In the present study, we evaluated the extracellular adenine nucleotide hydrolysis from rat lymphocytes submitted to the Walker 256 tumor model and a possible modulation of acetylsalicylic acid on nucleotidase activities from rat lymphocytes and rat blood serum submitted to the same model. Our results demonstrated a significant increase on ATP and ADP hydrolysis from rat lymphocyte ten days after the tumor induction and/or the ASA treatment. No alterations were observed to AMP hydrolysis. The ASA administration increased ATP and ADP hydrolysis from tumor-bearing rat lymphocytes. The transcriptional levels of NTPDases1-3 were significantly increased in the tumor presence and differently affected by ASA administration. In the blood serum, the ATP hydrolysis was altered by ASA only at 10 days of treatment whereas the ADP and AMP hydrolysis were altered at 6 and 10 days. The ASA administration in tumor-bearing rats promoted a significant reduction on ATP and AMP hydrolysis at 6 days of treatment. Considering our results, it is possible to conclude that modulation on nucleotide levels in lymphocytes seems not contribute to beneficial effects of ASA in cancer. By other hand, in the circulation, a potential beneficial effect of ASA on tumor was observed in the initial period of treatment. Thus, it is possible to suggest that ASA could have an important role in the tumor invasion, but does not seem to be effective after its installation and development in the host.

Made available in DSpace on 2014-06-11T19:30:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-02-21Bitstream added on 2014-06-13T20:20:34Z : No. of bitstreams: 1 morselli_jp_me_botib.pdf: 6036306 bytes, checksum: a1d3b81b03b0a6291da447d8dae4d178 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O presente trabalho teve por objetivo estudar, do ponto de vista taxonômico, as espécies de Lutosa Walker, 1869 (Orthoptera, Ensifera, Stenopelmatoidea, Anostostomatidae) que ocorrem nas florestas do leste do Estado de São Paulo, Brasil, abrangendo análises da morfologia corporal externa, do complexo fálico e espermateca. Além da re-descrição do gênero e de três espécies já conhecidas, treze novas foram descritas e uma chave dicotômica de identificação é proposta para todas as espécies examinadas. Com base na estrutura de certos elementos que compõem o complexo fálico, dois grupos de espécies foram reconhecidos e definidos. Ainda no que concerne à morfologia da genitália masculina, uma proposta de terminologia para as diferentes áreas do apódema epifálico é apresentada. Dados preliminares sobre hábitos, ecologia e comportamento de espécies de Lutosa são fornecidos. / The aim of the present work was to study, from a taxonomic perspective, the species of Lutosa Walker, 1869 (Orthoptera, Ensifera, Stenopelmatoidea, Anostostomatidae) from the eastern forests from the State of São Paulo, Brazil, including analyses of external body morphology, phallic complex and spermatheca. Besides re-describing the genus and three of its valid species, thirteen new ones were described, and a dichotomic identification key for all examined species is presented. Based on the structure of certain elements that comprise the phallic complex, two species groups were recognized and defined. Still regarding male genital morphology, a terminological proposal for the different areas of the epiphallic apodeme is presented. Preliminary data on habits, ecology, and behavior of Lutosa species are given.

Considerando as várias propriedades fisiológicas e patológicas já descritas para os nucleotídeos da adenina, muitos estudos têm sugerido um importante papel destas moléculas no desenvolvimento de tumores. Enquanto o ATP parece ser citotóxico às células tumorais, a adenosina possui uma atividade tumorogênica. Além disso, muitos estudos demonstram o envolvimento dos nucleotídeos na modulação da resposta imune. As ações induzidas pela sinalização purinérgica são reguladas pelas nucleotidases, que podem estar localizadas nas membranas celulares ou podem apresentar-se de forma solúvel no meio intracelular e/ou extracelular. Pertencem a este grupo de enzimas a família das nucleosídeo trifosfato difosfoidrolase (NTPDases), a família das nucleotídeo pirofosfatase/fosfodiesterase (NPPs) e a 5’-nucleotidase. Muitos estudos sugerem que o uso de antiinflamatórios não-esteroidais está associado com a proteção contra o desenvolvimento de muitos tipos de câncer. Neste estudo, nós avaliamos a hidrólise extracelular dos nucleotídeos da adenina em linfócitos de ratos adultos submetidos ao modelo tumoral de Walker 256, bem como uma possível modulação do ácido acetilsalicílico (AAS) nas atividades nucleotidásicas em linfócitos e soro de ratos submetidos ao mesmo modelo. Nossos resultados demonstraram um aumento significativo nas hidrólises de ATP e ADP em linfócitos no décimo dia após a indução tumoral e/ou o tratamento com AAS. Nenhuma alteração na hidrólise do AMP foi observada. A administração de AAS aumentou a hidrólise de ATP e ADP em linfócitos de ratos inoculados com o tumor. Os níveis transcricionais das NTPDases1-3 foram significativamente aumentados na presença do tumor e diferentemente afetados pela administração do AAS. No soro, a hidrólise do ATP foi alterada pelo AAS apenas no décimo dia de tratamento, enquanto as hidrólises de ADP e AMP foram alteradas no sexto e no décimo dias. A administração de AAS aos animais inoculados com o tumor promoveu uma redução significativa nas hidrólises de ATP e AMP no sexto dia. A partir desses resultados, podemos concluir que a modulação dos níveis dos nucleotídeos em linfócitos pareceu não contribuir para os efeitos benéficos do AAS no câncer. Por outro lado, na circulação, um efeito potencialmente benéfico do AAS sobre o tumor foi observado no período inicial de tratamento. Assim, é possível sugerir, que o AAS possa desempenhar um importante papel na prevenção da invasão do tumor, parecendo não ser mais efetivo após sua instalação e desenvolvimento no hospedeiro. / In addition to the various physiological and pathological properties already known for adenine nucleotides, an important role of these molecules in tumor development has been proposed. Whereas ATP has been shown to be cytotoxic for tumoral cells, adenosine has been shown to posses a tumor-promoting action. Moreover, many studies have also demonstrated the nucleotide involvement in immune response modulation. The actions induced by purinergic signaling are regulated by nucleotidases, that are located on cell membrane or they are present in soluble forms on the intracellular and/or extracellular milieu. These enzymes comprise the nucleoside triphosphate diphosphohydrolase family (NTPDases), the nucleotide pyrophosphatase/ phosphodiesterase family (NPPs) and the 5’- nucleotidase. Numerous studies have suggested that the use of non-steroidal antiinflammatory drugs can protect against the development of cancer. In the present study, we evaluated the extracellular adenine nucleotide hydrolysis from rat lymphocytes submitted to the Walker 256 tumor model and a possible modulation of acetylsalicylic acid on nucleotidase activities from rat lymphocytes and rat blood serum submitted to the same model. Our results demonstrated a significant increase on ATP and ADP hydrolysis from rat lymphocyte ten days after the tumor induction and/or the ASA treatment. No alterations were observed to AMP hydrolysis. The ASA administration increased ATP and ADP hydrolysis from tumor-bearing rat lymphocytes. The transcriptional levels of NTPDases1-3 were significantly increased in the tumor presence and differently affected by ASA administration. In the blood serum, the ATP hydrolysis was altered by ASA only at 10 days of treatment whereas the ADP and AMP hydrolysis were altered at 6 and 10 days. The ASA administration in tumor-bearing rats promoted a significant reduction on ATP and AMP hydrolysis at 6 days of treatment. Considering our results, it is possible to conclude that modulation on nucleotide levels in lymphocytes seems not contribute to beneficial effects of ASA in cancer. By other hand, in the circulation, a potential beneficial effect of ASA on tumor was observed in the initial period of treatment. Thus, it is possible to suggest that ASA could have an important role in the tumor invasion, but does not seem to be effective after its installation and development in the host.

Made available in DSpace on 2014-06-12T18:05:14Z (GMT). No. of bitstreams: 2 arquivo577_1.pdf: 3475189 bytes, checksum: 05c1943b3c5a1d5f1e44faecc54366cd (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2009 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / No século XX, a cosmologia deixou o campo da metafísica para ser consolidada como um ramo da ciência teórica e experimental. Nos últimos anos tem sido observado um grande avanço no importante aparato observacional da cosmologia tornando possível sondar eventos físicos que ocorreram a cerca de 13 bilhões de anos, supostamente ocorridos próximos à singularidade inicial conhecida como Big Bang. Entretanto, muitos mistérios permanecem esperando para ser resolvidos neste novo e promissor século. Entre eles estão as questões da formação de estruturas cosmológicas e das flutuações de densidade na radiação cósmica de fundo (CMB). A solução mais popular parece ser a chamada inflação cosmológica, a ideia de que um período de expansão acelerada ocorrido cerca de 10��43 s após o início do Universo poderia explicar as condições iniciais do Big Bang e o espectro da CMB. Neste trabalho, analisamos a generalidade do modelo mais simples e mais usado na literatura, o modelo f-FRW, e suas propriedades no espaço de fase da teoria. A ação estudada consiste na de Einstein-Hilbert onde supomos uma métrica do tipo Robertson-Walker acoplada com um campo escalar f e um potencial arbitrário V(f). Aplicamos a equação de Wheeler-DeWitt no modelo f-FRW e, então, propomos uma medida quântica no espaço de fase modificada pelo princípio holográfico de forma a contar heuristicamente a degenerescência proveniente dos graus de liberdade quânticos da gravitação

Richard Wright's Black Boy, Alice Walker's Meridian, and Ernest Gaines's The Autobiography of Miss Jane Pittman depict the African American struggle for rights and freedom both before, during, and after the recognized Civil Rights Era. By exploring the novels’ definitions of freedom, this work examines how these definitions inform the characters’ search for freedom. Using Wright, Walker, and Gaines to follow the freedom struggle from slavery to the post-civil rights era provides a comprehensive, historical framework for understanding the evolving rhetoric of freedom. Reflecting a “long,” complicated history of the Civil Rights Movement, these novels obscure a simplified, dichotomous understanding of the movement and provide a multivalent definition of freedom that encompasses both the political and psychological self. Ultimately, this research analyzes how these authors respond to each other and the racial and political climate of their time and examines how the search for freedom changes over time.

William Walker's expedition should be a fertile source of examples of such incipient dependency. This is because that expedition was grounded in the political desires of Manifest Destiny and the pragmatic economics of a cross-isthmus connection between the Atlantic and Pacific Oceans during the crucial years just before the U.S. Civil war. Walker's actions caused a war in Central America, brought the United States and England to the brink of war, effected a significant economic relationship, and influenced diplomatic relations between Nicaragua and the U.S. for years afterward. Because of these various actions and reactions, this episode in inter-American relations provides instances of many of the basic elements of the putative dependency relationships alluded to above. There were governments seeking economic advantage, businessmen seeking profitable investments, trade treaties negotiated, and military force used. It was a brief and intense period when economic interests were ultimately controlled by policy decisions.

No description available.

The Saltville thrust sheet in the southwest Virginia portion of the Appalachian foreland fold and thrust belt generally has very little penetrative deformation. At the southern termination of Walker Mountain however, a continuous 10-15 km zone along strike is highly strained and polydeformed. In this area a NW-trending mesoscopic solution cleavage and associated buckle folds are obliquely superimposed on the regional northeast structural trend. Values of penetrative strain, determined from syntectonic fibrous mineral growths in pressure fringes, vary along strike and vertically within the thrust sheet and indicate up to 50% shortening approximately orthogonal to cleavage. Fibers are virtually straight and undeformed reflecting a nearly coaxial strain history associated with cross-structural evolution. The cross-structures deform the Saltville sheet as well as the leading edge of the Pulaski sheet and were not rotated into their present orientation, but were initiated and evolved oblique to the northwest direction of tectonic transport. Cross-structural development is best explained by the oblique propagation of a portion of the frontal-tip of the evolving Saltivlle thrust in response to varying degrees of detachment. The variable ease with which the decollement was able to migrate through the rocks created zones of differential movement in the overlying sheet and the generation of locally high strains in the tip region. Spatial variation in strain and in the orientation of structural elements may be used to delineate zones of differential thrust movement. / M.S. / Bibliography: leaves 57-65.

This thesis explores the dynamics of two bipedal, passive-walker models that are free to move in a three-dimensional environment. Specifically, two rigid-bodied walkers that can sustain anthropomorphic gait down an inclined plane with gravity being the only source of energy were studied using standard dynamical systems methods. This includes calculating the stability of periodic orbits and varying the system parameter to create bifurcation diagrams and to address the persistence of a periodic solution under specific parameter variations. These periodic orbits are found by implementing the Newton-Raphson root solving scheme. The dynamical systems associated with these periodic orbits are not completely smooth. Instead, they include discontinuities, such as those produced due to forces at foot contact points and during knee hyper-extension. These discontinuities are addressed in the stability calculations through appropriate discontinuity mappings. The difference between the two walker models is the number of degrees of freedom (DOF) at the hip. Humans possess three DOF at each hip joint, one DOF at each knee joint, and at least two DOF at each ankle joint. The first walker model studied had revolute joints at the hips and knees and completely locked ankles. To make the walking motion more anthropomorphic, additional degrees of freedom were added to the hip. Specifically, the second walker model has ball joints at the hips. Two control algorithms are used for controlling the local stability of periodic motions for both walker models. The methods, reference and delay feedback control, rely on the presence of discontinuities in the system. Moreover, it is possible to predict the effects of the control strategy based entirely on information from the uncontrolled system. Control is applied to both passive walker models to try and stabilize an unstable periodic gait by making small, discrete, changes in the foot orientation during gait. Results show that both methods are successful in stabilizing an unstable walking motion for a 3D model with one DOF in each hip and to reduce the instability of the walking motions for the model having more mobility in the hip joints. / Master of Science