ScholarsArchive@OSU

    Involvement of PP6 in Dephosphorylation of Bcl11b, a Tumor Suppressor Transcription Factor

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    The purpose of this honors thesis research project is to investigate the molecular causes of childhood and infant T-cell acute lymphoblastic leukemias. T-cells are the work horses of the immune system, and like any organ, must develop properly to be fully functional. Improper development of thymocytes into T-cells can lead to development of T-cell leukemias and lymphomas. Regulation of thymocyte development is coordinated by transcription factors, of which Bcl1 1b is essential for proper T-cell development. Bcl1 1b is regulated by phosphorylation and dephosphorylation. Previously, a correlation was found between dephosphorylation of Bcl1 1b and increased expression of Id2 in developing T-cells. Regulation of the tumorigenic Id2 gene is crucial for proper T-cell development. Based on preliminary studies, we hypothesized that PP6 is the phosphatase responsible for dephosphorylating Bcl11b and altering transcriptional activity of the Id2 gene. DNA constructs for PP6 and Bcl11b proteins were transfected into HEK-293T cells, and then cells were lysed and assayed for Bcl11b phosphorylation. Our results indicated that PP6 co-expression increased Bcl11b dephosphorylation in HEK-293T cells. However, reporter gene assays showed that PP6 co-expression has no effect on Bcl11b-dependent repression of the Id2 promoter in transfected HEK-293T cells. The\ud next step is to investigate whether PP6 down-regulation of Bcl1 1b affects Id2 expression in native thymocytes

    A Study on Graphics Quality in Smartphone Games

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    As of February 2012, approximately 46% of American adults own a smartphone. The graphics quality of these devices gets better each year. However, they still have many more limitations in graphics processing and storage space than desktop computers. This means that applications on these devices should focus on optimizing their file sizes and graphics quality in order to maximize the number of devices that can run and store them. Unfortunately, there is no defined metric for graphics resolution on smartphones. This thesis explores what users believe to be the minimum acceptable graphics quality in smartphone games and graphics applications. By using a testing program we designed in OpenGL, we were able to find at what point in an image’s degradation users found it graphically unappealing and found the app unacceptable. Participants gauged four images that degraded over time. For our two high frequency images, participants found the minimum acceptable graphics quality to occur at 43 pixels per inch (ppi), while in low frequency images they found minimum acceptable graphics quality to occur at around 31 ppi, with the average minimum being 37 ppi

    Pseudo-spectral approximations of Rossby and gravity waves in a two-Layer fluid

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    Graduation date: 2012The complexity of numerical ocean circulation models requires careful checking with\ud a variety of test problems. The purpose of this paper is to develop a test problem involving\ud Rossby and gravity waves in a two-layer \ud fluid in a channel. The goal is to compute very\ud accurate solutions to this test problem. These solutions can then be used as a part of the\ud checking process for numerical ocean circulation models.\ud Here, Chebychev pseudo-spectral methods are used to solve the governing equations\ud with a high degree of accuracy. Chebychev pseudo-spectral methods can be described in\ud the following way: For a given function, find the polynomial interpolant at a particular\ud non-uniform grid. The derivative of this polynomial serves as an approximation to the\ud derivative of the original function. This approximation can then be inserted to differential\ud equations to solve for approximate solutions. Here, the governing equations reduce to\ud an eigenvalue problem with eigenvectors and eigenvalues corresponding to the spatial\ud dependences of modal solutions and the frequencies of those solutions, respectively.\ud The results of this method are checked in two ways. First, the solutions using the\ud Chebychev pseudo-spectral methods are analyzed and are found to exhibit the properties\ud known to belong to physical Rossby and gravity waves. Second, in the special case\ud where the two-layer model degenerates to a one-layer system, some analytic solutions are\ud known. When the numerical solutions are compared to the analytic solutions, they show\ud an exponential rate of convergence.\ud The conclusion is that the solutions computed using the Chebychev pseudo-spectral\ud methods are highly accurate and could be used as a test problem to partially check numerical\ud ocean circulation models

    Export marketing activities of small-firm lumber manufacturers

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    Asparagus

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    Published July 1934. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

    Methods college students use to solve probability problems and the factors that support or impede their success

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    Graduation date: 2003The purpose of this descriptive case study analysis was to provide portraits of the\ud methods college students used to solve probability problems and the factors that\ud supported or impeded their success prior to and after two-week instruction on probability.\ud Fourteen-question Pre- and Post-Instructional Task-Based Questionnaires provided\ud verbal data of nine participants enrolled in a college finite mathematics course while\ud solving problems containing simple, compound, independent, and dependent probabilistic\ud events.\ud Overall, the general method modeled by the more successful students consisted of\ud the student reading the entire problem, including the question; breaking down the\ud problem into sections, analyzing each section separately; using the context of the\ud question to reason a solution; and checking the final answer. However, this ideal method\ud was not always successful. While some less successful students tried to use this approach\ud when solving their problems, their inability to work with percents and fractions, to\ud organize and analyze data within their own representation (Venn diagram, tree diagram,\ud table, or formula), and to relate the process of solving word problems to the context of the\ud problem hindered their success solving the problem. In addition, the more successful\ud student exhibited the discipline to attend the class, to try their homework problems\ud throughout the section on probability, and to seek outside help when they did not\ud understand a problem.\ud However, students did try alternate unsuccessful methods when attempting to\ud solve probability problems. While one student provided answers to the problems based\ud on his personal experience with the situation, other students sought key words within the\ud problem to prompt them to use a correct representation or formula, without evidence of\ud the student trying to interpret the problem. While most students recognized dependent\ud events, they encountered difficulty stating the probability of a dependent event due to\ud their weakness in basic counting principles to find the size of the sample space. For those\ud students who had not encountered probability problems before the first questionnaire,\ud some students were able to make connections between probability and percent. Finally,\ud other inexperienced students encountered difficulty interpreting the terminology\ud associated with the problems, solving the problem based on their own interpretations

    The determinants of library prices of biology journals : an econometric analysis

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    Graduation date: 2003Increases in the prices of scholarly journals have exceeded the general rate of\ud inflation for the last decade and more. In the face of this "serials crisis," libraries have\ud found it increasingly difficult to maintain essential journal collections. This thesis\ud investigates the causes of the serials crisis in biology using data generated for a study\ud conducted by the Mann Library of Cornell University for 1988 and 1994 and updated\ud by the author for 2001.\ud The major goals of this thesis are to elaborate some alternative explanations of\ud the crisis, identify econometrically the chief determinants of biology journal prices,\ud and test the theory that prices are significantly determined by market structure.\ud Existing literature sheds some light on price determinants specifically, technical\ud characteristics (including frequency and size), publisher's legal form (profit vs. non-profit),\ud location (domestic or foreign) and scale (circulation) have been found to be\ud statistically significant--but this work is incomplete and sometimes contradictory.\ud OLS and GLS regression analysis conducted in this thesis confirms that the\ud determinants of biology journal prices are country of origin, journal size and\ud frequency, circulation, and publisher's legal form. There is no evidence, however, that\ud greater concentration increases prices. According to this analysis, monopoly power is\ud not a problem in biology journal publishing

    The genus Caenorhabditis : a system for testing evolutionary questions

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    Graduation date: 2013Caenorhabditis elegans is arguably the best understood animal on the planet.\ud Used for over 50 years to study development, we have a vast amount of knowledge of\ud the inner workings of this worm. Our knowledge is incomplete, however, without\ud placing this organism in its evolutionary and ecological context. In this body of work,\ud I focused on examining the evolutionary forces shaping Caenorhabditis nematodes,\ud with a particular emphasis on C. briggsae. In the first part, I examined the evolution\ud of mitochondrial genomes throughout the genus. I tested for signatures of selection\ud and examined the evolution of mitochondrial genome architecture. Through this, I\ud have shown that the mitochondrial genomes of Caenorhabditis nematodes appear to\ud be primarily influenced by purifying selection and that molecular evolutionary\ud inference is greatly limited by mutational saturation. The evolutionary forces acting\ud on mitochondrial genomes have been examined before, however, this study,\ud extensively examining this within a single genus, provides a much better\ud characterization than any of the studies to date. In the second part, I characterized the\ud evolutionary dynamics of mitochondrial pseudogenes in C. briggsae and its closest\ud relatives. I showed that these elements, while they might not evolve under strictly\ud neutral terms, are still quite useful in uncovering cryptic diversity and population\ud structure. I also observed that they appear/disappear in a manner that appears\ud inconsistent with one commonly held model for mitochondrial pseudogene evolution.\ud In the final part, I examined the evolution of C. briggsae in response to a biotic\ud environment. I showed that fitness in a parasite-containing environment incurs a\ud trade-off with fitness in the absence of parasites. Together, the chapters of this\ud dissertation demonstrate the strength of Caenorhabditis, and in particular C. briggsae,\ud for examining evolutionary questions and advances this system as a tool for\ud evolutionary biology research

    Parasite communities indicate effects of cross-shelf distributions, but not mesoscale oceanographic features on northern California Current mid-trophic food web

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    To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work.Mesoscale physical oceanographic features, such as jets and eddies, can influence the structure of marine ecosystems. We used trophically transmitted parasite communities of pelagic fishes in the northern California Current to examine effects of physical oceanographic features on pelagic ecosystem structure. We tested the hypotheses that (1) oceanographic features associated with a coastal promontory, Cape Blanco, Oregon (USA), produced a faunal break resulting in different pelagic ecosystems north and south of the cape, and that (2) the use of biological hotspots in the area by pelagic nekton is reflected in the trophic interactions of mid- and upper trophic level fishes. We recovered 19 taxa of trophically transmitted parasites from 10 common pelagic fish species caught between Newport, Oregon, and Crescent City, California. Non-metric multidimensional scaling of parasite communities reflected a trophic structure among these fish species; results were similar to published diet studies. We found no evidence in the trophically transmitted parasites of spatial differences between the pelagic ecosystems north or south of Cape Blanco, or within versus outside of the biological hotspots. However, we found significant cross shelf differences in parasite communities. Therefore, Cape Blanco does not seem to be a strong faunal boundary, rather the strongest influence is cross-shelf transport associated with coastal upwelling
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