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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
461

Fluorescent Dyes with Large Stokes Shifts of 80−200 nm for Optical Microscopy and Nanoscopy

Sednev, Maksim 08 June 2015 (has links)
No description available.
462

Combinatorial Interpretations Of Generalizations Of Catalan Numbers And Ballot Numbers

Allen, Emily 01 May 2014 (has links)
The super Catalan numbers T(m,n) = (2m)!(2n)!=2m!n!(m+n)! are integers which generalize the Catalan numbers. Since 1874, when Eugene Catalan discovered these numbers, many mathematicians have tried to find their combinatorial interpretation. This dissertation is dedicated to this open problem. In Chapter 1 we review known results on T (m,n) and their q-analog polynomials. In Chapter 2 we give a weighted interpretation for T(m,n) in terms of 2-Motzkin paths of length m+n2 and a reformulation of this interpretation in terms of Dyck paths. We then convert our weighted interpretation into a conventional combinatorial interpretation for m = 1,2. At the beginning of Chapter 2, we prove our weighted interpretation for T(m,n) by induction. In the final section of Chapter 2 we present a constructive combinatorial proof of this result based on rooted plane trees. In Chapter 3 we introduce two q-analog super Catalan numbers. We also define the q-Ballot number and provide its combinatorial interpretation. Using our q-Ballot number, we give an identity for one of the q-analog super Catalan numbers and use it to interpret a q-analog super Catalan number in the case m= 2. In Chapter 4 we review problems left open and discuss their difficulties. This includes the unimodality of some of the q-analog polynomials and the conventional combinatorial interpretation of the super Catalan numbers and their q-analogs for higher values of m.
463

The Super Bowl and Advertising: An Analysis of Firm Enhancement

Thomasson, Joshua M 01 January 2014 (has links)
This paper conducts an analysis of the short-term Firm Value Enhancement that companies experience during large-scale advertising campaigns, such as the Super Bowl. The findings suggest that these firms may experience a positive or negative return during the days after a large event, by signaling to investors and consumers the value of their firm through their advertisements. Some of the highlights include an approximately – 5% return for Super Bowl Advertisers on the Monday after the event, and underperformance during the two weeks surrounding the event.
464

炭素14と宇宙線変動 : 奈良時代の異変

Nakamura, Toshio, Nagaya, Kentarou, Miyake, Fusa, Masuda, Kimiaki, 中村, 俊夫, 永冶, 健太朗, 三宅, 芙沙, 増田, 公明 03 1900 (has links)
名古屋大学年代測定総合研究センターシンポジウム報告
465

Gene regulation during development by chromatin and the Super Elongation Complex

Dahlberg, Olle January 2014 (has links)
Developmental processes are carefully controlled at the level of transcription to ensure that the fertilized egg develops into an adult organism. The mechanisms that controls transcription of protein-coding genes ultimately ensure that the Pol II machine synthesizes mRNA from the correct set of genes in every cell type. Transcriptional control involves Pol II recruitment as well as transcriptional elongation. Recent genome-wide studies shows that recruitment of Pol II is often followed by an intermediate step where Pol II is halted in a promoter-proximal paused configuration. The release of Pol II from promoter-proximal pausing is thus an additional and commonly occurring mechanism in metazoan gene regulation. The serine kinase P-TEFb is part of the Super Elongation Complex that regulates the release of paused Pol II into productive elongation. However, little is known about the role of P-TEFb mediated gene expression in development. We have investigated the function of P-TEFb in early Drosophila embryogenesis and find that P-TEFb and other Super Elongation Complex subunits are critical for activation of the most early expressed genes. We demonstrate an unexpected function for Super Elongation Complex in activation of genes with non-paused Pol II. Furthermore, the Super Elongation Complex shares phenotypes with subunits of the Mediator complex to control the activation of essential developmental genes. This raises the possibility that the Super Elongation Complex has an unappreciated role in the recruitment of Pol II to promoters. The unique chromatin landscape of each cell type is comprised of post-translational chromatin modifications such as histone methylations and acetylations. To study the function of histone modifications during development, we depleted the histone demethylase KDM4A in Drosophila to evaluate the role of KDM4A and histone H3 lysine 36 trimethylation (H3K36me3) in gene regulation. We find that KDM4A has a male-specific function and regulates gene expression both by catalytic-dependent and independent mechanisms. Furthermore, we used histone replacement to investigate the direct role of H3K14 acetylation in a multicellular organism. We show that H3K14 acetylation is essential for development, but is not cell lethal, suggesting that H3K14 acetylation has a critical role in developmental gene regulation. This work expands our knowledge of the mechanisms that precisely controls gene regulation and transcription, and in addition highlights the complexity of metazoan development. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 3: Manuscript.</p>
466

Catalyzed Big Bang Nucleosynthesis and the properties of charged relics in the early universe

Koopmans, Kristen Alanna 27 August 2007 (has links)
The existence of charged electroweak-scale particles in the early universe can drastically affect the evolution of elemental abundances. Through the formation of Coulombic bound states with light nuclei, these exotic relic particles (hereafter referred to as X–) act to catalyze nuclear reactions by reducing their threshold energies. This thesis examines the properties of the X– bound states, and uses primordial element observations to constrain the abundance, lifetime, and mass of this exotic particle species. If the X– is a Dirac Fermion, its abundance relative to baryons is found to be YX- ~ 0.01, with a lifetime of 1500s ≤ τX- ≤ 3000s, and a mass of order 100 GeV. Assuming that the X– is a Scalar particle that decays into gravitinos, the resulting bounds become, 5x10-4 ≤ YX- ≤ 0.07, 1600s ≤ τX- ≤ 7000s, and 60GeV ≤ mX- ≤ 1000GeV. These ranges are consistent with Dark Matter constraints.
467

FPGA interconnection networks with capacitive boosting in strong and weak inversion

Eslami, Fatemeh 22 August 2012 (has links)
Designers of Field-Programmable Gate Arrays (FPGAs) are always striving to improve the speed of their designs. The propagation delay of FPGA interconnection networks is a major challenge and continues to grow with newer technologies. FPGAs interconnection networks are implemented using NMOS pass transistor based multiplexers followed by buffers. The threshold voltage drop across an NMOS device degrades the high logic value, and results in unbalanced rising and falling edges, static power consumption due to the crowbar currents, and reduced noise margins. In this work, circuit design techniques to construct interconnection circuit with capacitive boosting are proposed. By using capacitive boosting in FPGAs interconnection networks, the signal transitions are accelerated and the crowbar currents of downstream buffers are reduced. In addition, buffers can be non-skewed or slightly skewed to improve noise immunity of the interconnection network. Results indicate that by using the presented circuit design technique, the propagation delay can be reduced by at least 10% versus prior art at the expense of a slight increase in silicon area. In addition, in a bid to reduce power consumption in reconfigurable arrays, operation in weak inversion region has been suggested. Current programmable interconnections cannot be directly used in this region due to a very poor propagation delay and sensitivity to Process-Voltage-Temperature (PVT) variations. This work also focuses on designing a common structure for FPGAs interconnection networks that can operate in both strong and weak inversion. We propose to use capacitive boosting together with a new circuit design technique, called Twins transmission gates in implementing FPGA interconnect multiplexers. We also propose to use capacitive boosting in designing buffers. This way, the operation region of the interconnection circuitry is shifted away from weak inversion toward strong inversion resulting in improved speed and enhanced tolerance to PVT variations. Simulation results indicate using capacitive boosting to implement the interconnection network can have a significant influence on delay and tolerance to variations. The interconnection network with capacitive boosting is at least 34% faster than prior art in weak inversion. / Graduate
468

Investigation of Nanoparticles for Use in Microwave Systems in Biomedicine

Taghavi, Houra 03 October 2013 (has links)
This research focuses on the microwave properties of nanoparticles for use as contrast and hyperthermia agents. Currently, visible light is used for irradiation of nanoparticles as hyperthermia agents. Additionally, visible/Near-infrared light is used for photoacoustic tomography (PAT) imaging. Compared to optical wavelengths, frequencies in microwave range transmit through tissue with high penetration depth . Thus, deep cancerous cells and malignant tissue may be treated and imaged. These nanoparticles could enable the use of a hybrid microwave/acoustic technique known as thermoacoustic tomography. Here, quantitative measurements of the heat generation in super paramagnetic iron oxide nanoparticle (SPIONs), gold nanoparticles (AuNPs), and gold nanoclusters (AuNCs) induced by microwave energy at 3 GHz, are presented and compared. Based on our experiments, SPIONs are the most efficient nanoparticles for microwave heating. Very high concentrations of SPIONs are able to convert microwave energy into heat about 22° C more than DI-water. AuNPs, which support plasmon resonances, do not provide heat under microwave irradiation as predicted by our computational analysis based on Mie Theory. AuNCs are a new form of ultra-small (<2.5 nm) AuNPs which do not support plasmonic resonances and have supra-molecular properties such as sub-conduction band transitions. Interestingly, AuNCs have the potential to absorb microwave energy and may provide an alternative to SPIONs. These nanoparticles had not yet been studied before in this frequency region. In addition, the absorption coefficient of nanoparticles were calculated using complex permittivity data from a dip probe kit and a Vector Network Analyzer (VNA) in a broad band range from 500 MHZ to 10 GHz. This method allows identification of best frequency region with highest penetration depth. In the last step, the nanoparticles with different concentrations were tested as exogenous contrast agents in a Thermoacoustic Tomography (TAT) system. TAT utilizes the penetration depth of microwave energy while producing high resolution images through acoustic waves. The addition of an exogenous contrast agent improves image quality by more effectively converting microwave energy to heat. The experiment reveals that the time resolved thermoacoustic signal (TA) from SPIONs is stronger than AuNPs and AuNCs and thus, the image contrast produced by SPIONs is stronger than the two other aforementioned nanoparticles.
469

A Composite Frame/joint Super Element For Structures Strengthened By Externally Bonded Steel/frp Plates

Kaymak, Yalcin 01 January 2003 (has links) (PDF)
A materially non-linear layered beam super element is developed for the analysis of RC beams and columns strengthened by externally bonded steel/FRP plates. The elasto-plastic behavior of RC member is incorporated by its internally generated or externally supplied moment-curvature diagram. The steel plate is assumed to be elasto-plastic and the FRP laminate is assumed to behave linearly elastic up to rupture. The thin epoxy layer between the RC member and the externally bonded lamina is simulated by a special interface element which allows for the changing failure modes from steel plate yielding/FRP plate rupture to separation of the bonded plates as a result of bond failure in the epoxy layer. An empirical failure criterion based on test results is used for the epoxy material of the interface. The most critical aspect of such applications in real life frame structures is the anchorage conditions at the member ends and junctions. This has direct influence on the success and the effectiveness of the application. Therefore, a special corner piece anchorage element is also considered in the formulation of the joint super element, which establishes the fixity and continuity conditions at the member ends and the joints.
470

An Examination Of Super Resolution Methods

Sert, Yilca Baris 01 April 2006 (has links) (PDF)
The resolution of the image is one of the main measures of image quality. Higher resolution is desired and often required in most of the applications, because higher resolution means more details in the image. The use of better image sensors and optics is an expensive and also limiting way of increasing pixel density within the image. The use of image processing methods, to obtain a high resolution image from low resolution images is a cheap and effective solution. This kind of image enhancement is called super resolution image reconstruction. This thesis focuses on the definition, implementation and analysis on well-known techniques of super resolution. The comparison and analysis are the main concerns to understand the improvements of the super resolution methods over single frame interpolation techniques. In addition, the comparison also gives us an insight to the practical uses of super resolution methods. As a result of the analysis, the critical examination of the techniques and their performance evaluation are achieved.

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