Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 179-194).

No description available.

This study endeavors to give an insight into the causes and characteristics of price fluctuations of spot cotton at New York, N.Y., for the period 1911-1953, and to indicate whenever possible the factors which caused the price of cotton to rise or fall during selected periods.

Semiconductor Electroabosortion Modualtor (EAM) has become an important element in optical fiber communications because of its capability to integrate with other semiconductor devices, high-speed and low driving voltage. However, high optical insertion loss and low tolerance in optical power coupling are main general problems to be solved in order to get high electro-optical (EO) efficiency. Monolithically integrating EAM with optical spot-size converter (SSC) can lead to high-efficiency single-mode fiber coupling, but the price is on the complex fabrication methods. In this paper, based on previous work, the selective undercut etching active region (UEAR) and the whole wet-etching techniques are employed to fabricate the integration of laterally tapered SSC and EAM. Also, by applying the ion-implantation in SSC region, the reliable transfer efficiency and also high-speed performance are obtained based on the high resistance and low parasitic capacitance in SSC. The active region containing 10 strain compensated multiple-quantum-wells (MQWs) sandwiched by n-InP (bottom) and p-InP (top) for the electroabsorption region of EAM and also the top region of lateral tapered SSC. The converted waveguide in SSC consists of alternating InGaAsP and InP layers. An HBr-base etching solution is first used to define the top p-cladding with the widths of from 6um to 8um. An H2O2-base solution is then utilized to selectively undercut-etch the MQWs from InP material. The active waveguide p-cladding in EAM is set as 8um. After defining EAM and SSC, the converted waveguide is fabricated by aligning the top SSC and then wet-etched. By using an e-beam evaporator, Ti/Pt/Au and Ni/AuGe/Ni/Au are deposited as p- and n-type metallization, respectively. PMGI is spun serving as the passivation, planarization and bridging. The microwave coplanar waveguide (CPW) line is finally defined by depositing Ti/Au for microwave load- and feed- lines and connecting EAM. The length of SSC is 350um. The Spot-Size Converter monolithically integrated with Electroabsortion Modulator using whole wet-etching technique is demonstrated. ¡V12.5dB of fiber-to-fiber insertion loss and 10dB (TE) 10dB(TM) extinction ration in 1V(1570nm excitation) is obtained in this device. Using Fabry-Perot method, the average optical transfer loss in SSC is extracted to be 2dB, quite consistent with simulation results. By applying ion-implantation on SSC, the broadband EO performance 45GHz of ¡V3dB bandwidth is achieved for 100um long device due to the low capacitance and the high resistivity in SSC.

We present the fabrication of InGaAsP/InP buried heterostructure spot-size converter lasers. In the lateral conversion, we use photolithography to make tapered ridge waveguides. In the vertical conversion, we use a pair of step-index passive waveguides, namely guard waveguides (GWs), in the two sides of the step-index active waveguide region to increase optical-field profile. In order to decrease leakage current, we use a p-n-p current blocking structure by MOCVD regrowth. From numerical simulations, the far-field divergence is 21x21. The step-index GW structure shows an internal efficiency of 63%. However, the BH lasers did not lase from our fabrication processes. From the I-V characteristics, a large leakage current has bypassed through the blocking structure. The reason may relate to the high background doping concentration of our MOCVD growth.

Abstract Optical spot-size converter (SSC) is an essential element in the opto-electronic integrated circuit because of its direct coupling to single-mode optical fiber, low-cost from the misalignment issue in package. By the tapered waveguide structure, SSC offers a capability to transfer an elliptical optical mode of optical waveguide to single-mode fiber matched mode, allowing the independence of device design from the coupling issue. However, the conversion efficiency of SSC is strongly reliant on tapered waveguide structure, material index, and also excitation wavelengths, restricting design and fabrication of SSC. In order to enhance the reliability on SSC fabrication, a voltage-controllable SSC integrated with electroabsorption modulator (EAM) is designed and fabricated. The tapered waveguide processing is based on the selective undercut wet-etching on InGaAsP-material system. The active waveguide width of EAM is 3.5£gm, where the tapered waveguide widths is ranged from 1.7£gm to 3.5£gm. The transferred optical waveguide (passive waveguide) is 8£gm wide. By adjusting the voltage of tapered waveguide, coupling efficiency is enhanced by 2dB from 1560nm to 1570nm. A reliable SSC-integrated EAM with -12dB of insertion loss, extinction ratio of 22dB is demonstrated. By extracting the index change from Fabry-Perot optical mode of waveguide, index variation from reverse bias is in the order of 10-3, consistent with the calculation based on Kramer-Kronig model.

The expert blind spot hypothesis provides an explanation as to why experts with superior content knowledge find it difficult to communicate this knowledge to novices. Previous studies have shown that as predicted by the expert blind spot hypothesis, participants with more advanced mathematics education are more likely to believe in the necessity of symbolic reasoning and mastery of equations as a prerequisite for algorithmic or mathematical problem solving. This pattern has been shown across several subject areas including mathematics, science, and language arts. While there has been a good deal of work done identifying this issue, findings have been slow to transfer to teachers in the field. This project integrates findings regarding the expert blind spot into an online training module that will educate in-service teachers about the expert blind spot and provide strategies to overcome its pitfalls. / text

Acyl carrier protein plays an essential role in bacterial fatty acid synthesis and has been recognized as an attractive new antibiotic target. In a previous study using TAP tagged ACP, we identified two ACP binding partners not directly involved in lipid metabolism, AidB and SpoT, that showed increased binding to ACP in stationary phase. In the current project, we found that the increase in binding of SpoT, a stringent response protein, to ACP appears to be due to increased affinity. In contrast, the increase in binding of AidB, an adaptive response protein, appears to be due to increased expression of AidB. Transformation of SpoT-TAP strains with pGEX-ACP vectors followed by purification revealed that SpoT interacts with wild type ACP, but not with ACP mutants that neutralized helix II or cannot fold properly. We used a far western approach to confirm the direct interaction between ACP and AidB in vitro. Overall, these results support the hypothesis that interaction of ACP with SpoT is highly specific and may reflect a regulatory role for ACP, while that with AidB might reflect non-specific interactions.

No description available.

O Vírus Zika é um arbovírus pertencente à família Flaviviridae e ao gênero Flavivirus, é constituído por RNA de cadeia simples senso positivo e foi primeiramente descrito em 1947 na floresta de Ziika, em Uganda. Este estudo, visa mapear os epitopos do Vírus Zika (ZIKV), experimento que nos permite avaliar e compreender a resposta imune do hospedeiro contra o vírus por meio da detecção de regiões imunodominantes nas proteínas virais. O processo de identificação dos epitopos de ZIKV foi realizado pela técnica de spot synthesis, que se baseia em arranjos de peptídeos relacionados às proteínas do ZIKV. Amostras de soro de pacientes residentes em áreas endêmicas de arboviroses, mães e bebês que apresentaram sintomatologia típica foram selecionadas e triadas pelo método de ELISA e PCR real time. Sequências de referência do vírus foram submetidas a análises in sílico, para a determinação das áreas de interação na superfície da proteína e suas características antigênicas, para efeito de comparação com a resposta observada pelas amostras. Os experimentos evidenciaram um alta antigenicidade nas proteínas estruturais do vírus, e em nas não-estruturais 1,3 e 5. / The Zika virus is an arbovirus belonging to the genus Flavivirus of the Flaviridae family. It consists of single-stranded positive-sense RNA and was first described in 1947 in the Ziika Forest in Uganda. This study aims to map the Zika virus (ZIKV) epitopes, in an experimental design that allows us to evaluate and understand the immune response of the host against the virus by detecting immunodominant regions in the viral proteins. The process of identification of the ZIKV epitopes was performed by the spot synthesis technique, which is based on peptide arrangements related to the ZIKV proteins. Serum samples from patients living in arboviruses endemic areas, mothers and infants presenting typical symptoms were selected and screened by ELISA and real time PCR. Reference sequences of the virus were submitted to in silico analyzes to determine the interaction areas on the surface of the protein and its antigenic characteristics, for comparison with the response observed by using serum samples. The experiments demonstrated a high antigenicity in the structural proteins of the virus, and in the non-structural proteins 1, 3 and 5.