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2013

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Articles 10831 - 10860 of 11462

Full-Text Articles in Physical Sciences and Mathematics

Visual-Textual Joint Relevance Learning For Tag-Based Social Image Search, Yue Gao, Meng Wang, Zheng-Jun Zha, Jialie Shen, Xuelong Li, Xindong Wu Jan 2013

Visual-Textual Joint Relevance Learning For Tag-Based Social Image Search, Yue Gao, Meng Wang, Zheng-Jun Zha, Jialie Shen, Xuelong Li, Xindong Wu

Research Collection School Of Computing and Information Systems

With the popularity of social media websites, extensive research efforts have been dedicated to tag-based social image search. Both visual information and tags have been investigated in the research field. However, most existing methods use tags and visual characteristics either separately or sequentially in order to estimate the relevance of images. In this paper, we propose an approach that simultaneously utilizes both visual and textual information to estimate the relevance of user tagged images. The relevance estimation is determined with a hypergraph learning approach. In this method, a social image hypergraph is constructed, where vertices represent images and hyperedges represent …

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Optical Characterization Of Magnetism In Magnetic/Nonmagnetic Heterostructures, Yichun Fan Jan 2013

Optical Characterization Of Magnetism In Magnetic/Nonmagnetic Heterostructures, Yichun Fan

Dissertations, Theses, and Masters Projects

This thesis focuses on the study of the static and dynamic magnetic interactions in ferromagnetic/nonmagnetic heterostructures using interface-specific and time-resolved optical techniques. The goal of this thesis is to elucidate the interface exchange coupling, magnetic anisotropy, and coherent spin dynamics in these advanced material systems, crucial to the realization of high performance spintronic devices.;First, a pronounced exchange bias (EB) phenomenon is observed in Fe/MgO (001) by magnetic second harmonic generation. The bulk magnetization does not, in marked contrast to typical systems where EB is manifested only in the net magnetization. The magnitude of the exchange bias varies with interface oxygen …

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Multi-Meson Systems From Lattice Quantum Chromodynamics, Zhifeng Shi Jan 2013

Multi-Meson Systems From Lattice Quantum Chromodynamics, Zhifeng Shi

Dissertations, Theses, and Masters Projects

Systems of non-zero isospin chemical potential ( muI), where the chemical potential for up and down quarks is equal in magnitude but of opposite sign, do not suffer from the sign problem, and normal LQCD techniques can be successfully adapted to study such systems. From chiral perturbation theory (chiPT), in addition to the deconfined phase transition at high temperature at zero chemical potential, another phase transition from ordinary hadronic states to a Bose Einstein Condensate (BEC) state has been conjectured [1] at non-zero isospin chemical potential. Such a BEC phase is of phenomenological relevance in the interior of neutron stars.;In …

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Applications Of Holographic Dualities, Dylan Judd Albrecht Jan 2013

Applications Of Holographic Dualities, Dylan Judd Albrecht

Dissertations, Theses, and Masters Projects

We introduce and review some of the building blocks to what is known as the AdS/CFT correspondence. We then present, using the framework of the correspondence, two applications: one to QCD (Chapters 2 and 3) and one to superconductivity (Chapter 4). The work presented in these chapters was carried out by the author and collaborators during the author's graduate studies.

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Improving Security And Privacy In Online Social Networks, Wei Wei Jan 2013

Improving Security And Privacy In Online Social Networks, Wei Wei

Dissertations, Theses, and Masters Projects

Online social networks (OSNs) have gained soaring popularity and are among the most popular sites on the Web. With OSNs, users around the world establish and strengthen connections by sharing thoughts, activities, photos, locations, and other personal information. However, the immense popularity of OSNs also raises significant security and privacy concerns. Storing millions of users' private information and their social connections, OSNs are susceptible to becoming the target of various attacks. In addition, user privacy will be compromised if the private data collected by OSNs are abused, inadvertently leaked, or under the control of adversaries. as a result, the tension …

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Improving Energy Efficiency And Security For Pervasive Computing Systems, Fengyuan Xu Jan 2013

Improving Energy Efficiency And Security For Pervasive Computing Systems, Fengyuan Xu

Dissertations, Theses, and Masters Projects

Pervasive computing systems are comprised of various personal mobile devices connected by the wireless networks. Pervasive computing systems have gained soaring popularity because of the rapid proliferation of the personal mobile devices. The number of personal mobile devices increased steeply over years and will surpass world population by 2016.;However, the fast development of pervasive computing systems is facing two critical issues, energy efficiency and security assurance. Power consumption of personal mobile devices keeps increasing while the battery capacity has been hardly improved over years. at the same time, a lot of private information is stored on and transmitted from personal …

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Real-Time High-Quality Image To Mesh Conversion For Finite Element Simulations, Panagiotis Foteinos Jan 2013

Real-Time High-Quality Image To Mesh Conversion For Finite Element Simulations, Panagiotis Foteinos

Dissertations, Theses, and Masters Projects

Technological Advances in Medical Imaging have enabled the acquisition of images accurately describing biological tissues. Finite Element (FE) methods on these images provide the means to simulate biological phenomena such as brain shift registration, respiratory organ motion, blood flow pressure in vessels, etc. FE methods require the domain of tissues be discretized by simpler geometric elements, such as triangles in two dimensions, tetrahedra in three, and pentatopes in four. This exact discretization is called a mesh . The accuracy and speed of FE methods depend on the quality and fidelity of the mesh used to describe the biological object. Elements …

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Experimental And Computational Studies Of Environmentally Persistent Free Radicals (Epfrs) Formation, Lucy W. Kiruri Jan 2013

Experimental And Computational Studies Of Environmentally Persistent Free Radicals (Epfrs) Formation, Lucy W. Kiruri

LSU Doctoral Dissertations

The first part of the thesis investigates the use of theoretical quantum calculations for the study of EPFRs as the initial and fundamental step in the formation of polychlorinated dibenzo-p-dioxin and dibenzofuran. The computational model comprised of density functionals (B3LYP, PBE1PBE, and M06) and two types of basis set namely: LANL2DZ for all atoms and GEN (LANL2DZ for metals and aug-cc-pVDZ for non-metals). Full mechanisms of EPFRs formation over (CuO)1-8, and aluminum oxide clusters were studied. The most stable intermediates and products have been determined and compared to available experimental data. In case of (CuO)1-8 clusters, the small clusters are …

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Incorporating Science-Based Approaches Into The Rapid Assessment Of Wetlands And Streams : Validation, Restoration Trajectory, And Method Development, Jacob Franklin Berkowitz Jan 2013

Incorporating Science-Based Approaches Into The Rapid Assessment Of Wetlands And Streams : Validation, Restoration Trajectory, And Method Development, Jacob Franklin Berkowitz

LSU Doctoral Dissertations

Human alterations within wetlands and streams have resulted in a decrease in ecological functions and associated benefits to society. The scientific literature highlights the functional benefits provided by ecosystems including flood protection, nutrient cycling, and habitat maintenance. Additionally, legislation and regulatory policy require mitigation and restoration as compensation for declines in ecological functions. As a result, the need for practical, repeatable, and technically sound ecosystem assessment methods remains essential to natural resource management. However, few studies determine the validity of rapid assessment approaches by applying quantitative parameters, especially with respect to biogeochemical functions. We assessed biogeochemical functions applied to restored …

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Foraging Ecology And Habitat Use Of The Northern Diamondback Terrapin (Malaclemys Terrapin Terrapin) In Southern Chesapeake Bay, Diane C. Tulipani Jan 2013

Foraging Ecology And Habitat Use Of The Northern Diamondback Terrapin (Malaclemys Terrapin Terrapin) In Southern Chesapeake Bay, Diane C. Tulipani

Dissertations, Theses, and Masters Projects

The northern diamondback terrapin (Malaclemys terrapin ) is the only estuarine turtle residing along western Atlantic and Gulf of Mexico coasts of North America. Through predation, terrapins may be a key species in coastal marine habitats by exerting top-down control on marsh invertebrates, and thereby help to maintain healthy marshes. Despite the terrapin's ecological importance, there has not been a thorough study of terrapin foraging ecology and movements in lower Chesapeake Bay. In this dissertation, the research focused on the foraging habits of diamondback terrapins and their effects within salt marsh and seagrass habitats of lower Chesapeake Bay. I provided …

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Amplifying Conjugated Polymers For Fluorescent Chemosensing, Deepa Pangeni Jan 2013

Amplifying Conjugated Polymers For Fluorescent Chemosensing, Deepa Pangeni

LSU Doctoral Dissertations

Chemo- and biosensors based on fluorescent conjugated polymers benefit from greater detection sensitivity due to amplification of the electronic perturbations produced by analyte binding. This amplification stems from the exciton-transporting properties of conjugated polymers. In the conventional sensor design paradigm, excitons migrate from the bulk of the polymer to the analyte binding sites which can be either fluorescence quenching sites (turn-off sensors) or lower energy fluorophores (turn-on sensors). In this dissertation, we proposed an alternative design paradigm when analyte binding creates a higher energy gap site in the polymer backbone. In the case of isolated polymer chains in dilute solution, …

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Microfluidics For The Analysis Of Integral Membrane Proteins: A Top-Down Approach, Katrina Nychole Battle Jan 2013

Microfluidics For The Analysis Of Integral Membrane Proteins: A Top-Down Approach, Katrina Nychole Battle

LSU Doctoral Dissertations

The development of fully automated and high-throughput systems for proteomics is now in demand because of the need to generate new protein-based disease biomarkers. Unfortunately, it is difficult to identify protein biomarkers that are low abundant when in the presence of highly abundant proteins, especially in complex biological samples like serum, cell lysates, and other biological fluids. Membrane proteins, which are in many cases of low abundance compared to cytosolic proteins, have various functions and can provide insight into the state of disease and serve as targets for new drugs making them attractive biomarker candidates. Traditionally, proteins are identified through …

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A Raman Spectroscopic Study Of The Effects Of Hydrogen Bonding On 1,2,3-Triazole, Anna Craig Jan 2013

A Raman Spectroscopic Study Of The Effects Of Hydrogen Bonding On 1,2,3-Triazole, Anna Craig

Honors Theses

The goal of this thesis is to analyze the effects of hydrogen bonding on liquid 1H- 1,2,3-triazole. Spectra of neat 1H-1,2,3-triazole are compared to simulated spectra and are found to differ greatly. The experimental spectrum, however, matches the simulated spectra of 1H-1,2,3-triazole dimers very well. This suggests that dimers play a large role in the liquid structure of 1H-1,2,3-triazole. Though tautomerism is thought to play a large role in the vibrational behavior of 1,2,3- triazole, the Raman spectra obtained here suggest that molecular dimers dominate the liquid state much more so than tautomerism. Even in aqueous solution, the simulated spectra …

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Spectroscopic Study Of Charge Transfer Induced Blue Shifting Of Pyrimidine/Water Mixtures On Silver Substrate, Annie Katherine Mcclellan Jan 2013

Spectroscopic Study Of Charge Transfer Induced Blue Shifting Of Pyrimidine/Water Mixtures On Silver Substrate, Annie Katherine Mcclellan

Honors Theses

Surface enhanced Raman spectroscopy (SERS) is a chemical method gaining much popularity in recent years. With the use of a roughened metal surface or metal nanoparticles, surface plasmon resonances enhance the electromagnetic field allowing for increased Raman signal. Pyrimidine, having two lone pairs of electrons, is capable of charge transfer interactions contributing to a SERS chemical enhancement factor as well. It has recently been reported that hydrogen bonding with water results in the blue-shifting of certain normal modes of pyrimidine. By comparing experimental polarized Raman spectra with the results of electronic structure calculations, the origin of this blue-shifting was found …

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Ph Dependent Proteolysis Of Neural Cadherin, Candice Ashton Walters Jan 2013

Ph Dependent Proteolysis Of Neural Cadherin, Candice Ashton Walters

Honors Theses

Cadherins are the primary calcium-dependent cell-cell adhesion molecule and are essential to vertebrates. They ensure the integrity of epithelial barriers that allow for maintenance of homeostasis in humans and protection against invading microorganisms. A common invader capable of forging past this line of defense is the fungus Candida albicans. The main virulence mechanism of C. alibans in acidic environments is its secreted aspartyl proteinases (SAPs), which are hydrolytic enzymes that degrade cadherin-mediated cell adhesion leading to infection of the underlying tissues. Cadherin is normally resistant to cleavage by proteases due to stabilization of the protein structure by bound calcium and …

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Effects Of Micro-Solvation On Room Temperature Ionic Liquids, Joseph Wellington Golden Jan 2013

Effects Of Micro-Solvation On Room Temperature Ionic Liquids, Joseph Wellington Golden

Honors Theses

Room temperature ionic liquids (RTILs) have received much attention lately. These compounds are made completely of ions and are liquid at or near room temperature. These liquid salts have a number of unique properties that make them an interesting system to study. These properties include almost zero vapor pressure, thermal stability, large liquidus range, etc. Due to these properties and others, ionic liquids (ILs) have attracted much attention in the emerging field of green chemistry as potentially new solvents for many of the hazardous and volatile solvents currently in use. Moreover, the complex interactions of the anion and cation systems …

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Skein Theory And Topological Quantum Field Theory, Xuanting Cai Jan 2013

Skein Theory And Topological Quantum Field Theory, Xuanting Cai

LSU Doctoral Dissertations

Skein modules arise naturally when mathematicians try to generalize the Jones polynomial of knots. In the first part of this work, we study properties of skein modules. The Temperley-Lieb algebra and some of its generalizations are skein modules. We construct a bases for these skein modules. With this basis, we are able to compute some gram determinants of bilinear forms on these skein modules. Also we use this basis to prove that the Mahler measures of colored Jones polynomial of a sequence of knots converges to the Mahler measure of some two variable polynomial. The topological quantum field theory constructed …

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Transport In Correlated And Uncorrelated Random Media, With Applications To Molecularly Doped Polymers, Nilanka Praveena Gurusinghe Jan 2013

Transport In Correlated And Uncorrelated Random Media, With Applications To Molecularly Doped Polymers, Nilanka Praveena Gurusinghe

Doctoral Dissertations

"The commonly observed Poole-Frenkel field dependence; of the mobility of photo-injected charges in molecularly-doped polymers has been shown to arise from the spatially-correlated, Gaussian energy distribution of transport sites encountered by charges moving through the material. Experimental current-time transients obtained for molecularly-doped polymers exhibit universality with respect to electric field and a metal-insulator-like transition from non-dispersive to dispersive transport, features usually identified with multiple trapping models that assume an uncorrelated exponential distribution of trap energies. For materials that exhibit both sets of features the possibility arises that both kinds of disorder coexist. We study here, analytically and numerically, transport in …

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Study Of Artificially Disordered Optical Fibers, Herath Mudiyanselage Sumudu Rasika Kumari Herath Jan 2013

Study Of Artificially Disordered Optical Fibers, Herath Mudiyanselage Sumudu Rasika Kumari Herath

Doctoral Dissertations

"Light transmission through photo-sensitive multi-mode fibers (MMF) with controlled volume disorder is investigated. Experiment shows that a segment of disordered MMF as short as 10 cm is sufficient to distribute power uniformly over all co-propagating modes and the intensity at the output surface of the fiber follows the Rayleigh negative exponential function. To explain the experimental findings, a comprehensive theoretical model is developed with three main results. First, statistical properties of all components of the dielectric tensor are obtained and analyzed in the framework a microscopical model of photo-sensitivity in a germano-silicate glasses. Secondly, it is shown that induced birefringence …

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Optical Spectroscopic Studies Of Two Star Forming Regions, Kristen Leilani Erickson Jan 2013

Optical Spectroscopic Studies Of Two Star Forming Regions, Kristen Leilani Erickson

Doctoral Dissertations

"The ρ Ophiuchi and Serpens molecular clouds are sites of low mass star formation. The goals of this study were to identify young stellar objects (YSOs) and estimate ages and masses in order to infer an initial mass function (IMF), investigate disk evolution, and determine the star-forming history. Optical spectroscopic surveys of an unbiased sample of candidate young stars have been completed. Optical images taken in different photometric bands were used to create color-magnitude diagrams from which sources were selected for spectroscopic observation. In combination with published data, 135 association members in ρ Ophiuchi and 63 association members plus 16 …

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Quantum Phase Transitions In Impurity Models And Percolating Lattices, Manal M. Al-Ali Jan 2013

Quantum Phase Transitions In Impurity Models And Percolating Lattices, Manal M. Al-Ali

Doctoral Dissertations

"This thesis investigates the influence of random disorder and dissipation on zero-temperature quantum phase transitions. Both phenomena can fundamentally change the character of the phases of a quantum many-particle system and of the transitions between them. If dissipation and disorder occur simultaneously in a system undergoing a quantum phase transition, particularly strong effects can be expected. In the first paper reproduced in this thesis, we study a single quantum rotor coupled to a sub-Ohmic dissipative bath. We find that this system undergoes a quantum phase transition from a delocalized phase to a localized phase as the dissipation strength is increased. …

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Design, Synthesis, And Characterization Of Porphyrin Derivatives For Biological Applications, Raja Gabadage Waruna Eranga Jinadasa Jan 2013

Design, Synthesis, And Characterization Of Porphyrin Derivatives For Biological Applications, Raja Gabadage Waruna Eranga Jinadasa

LSU Doctoral Dissertations

Chapter 1 of this Dissertation presents a brief introduction to the basic properties of porphyrins and their derivatives (hydroporphyrins), their abundance and functions in the nature, and their applications in photodynamic therapy. Chapter 2 reports the synthesis, characterization, conformational analysis and cellular studies of novel mono conjugated regioisomers of chlorin e6 derivatives that are promising photosensitizers for photodynamic therapy. All three regioisomers were synthesized from pheophytin a, which was extracted from the alga Spirulina pacifica. In vitro investigations using human carcinoma HEp2 cells show that the 152-lysyl regioisomers accumulate the most within cells, and the most phototoxic …

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Modeling The Formation Of Periodic Hypoxia In Partially Mixed Estuaries And Its Response To Oligotrophication And Climate Change, Samuel J. Lake Jan 2013

Modeling The Formation Of Periodic Hypoxia In Partially Mixed Estuaries And Its Response To Oligotrophication And Climate Change, Samuel J. Lake

Dissertations, Theses, and Masters Projects

The development of hypoxia represents one of the most common and ecologically detrimental effects of anthropogenic nutrient enrichment in coastal marine ecosystems. Due to the physiological importance of oxygen as a key component of metabolic processes, the development and persistence of hypoxia can reduce the distribution of important species, modify food webs, decrease diversity and richness, and sub-lethally affect growth and reproductive rates. While many recent studies have focused on the global increase in hypoxia and highlighted the need for nutrient reduction strategies, some key processes associated with hypoxia remain understudied. of particular importance is the resolution of the major …

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Food Availability And Utilization For Cultured Hard Clams, Richard Garrik Secrist Jan 2013

Food Availability And Utilization For Cultured Hard Clams, Richard Garrik Secrist

Dissertations, Theses, and Masters Projects

Aquaculture of the hard clam Mercenaria mercenaria is a valuable industry on the east coast. At high planting densities, cultured bivalves can become limited by food availability, resulting in reduced growth. Centric diatoms are considered the dominant food source to cultured bivalves. Alternative sources may also be important, including resuspended benthic microalgae (pennate diatoms) and detritus from macroalgae growing on predator exclusion nets. This study measured (1) the availability of different food sources in clam beds at Cherrystone Inlet in Chesapeake Bay, including the effects of macroalgae on food availability, and (2) the clearance rates and absorption efficiencies by cultured …

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Holocene Sedimentation On The Lanyang Plain And Adjacent Continental Shelf, Northwestern Taiwan, Chia-Yu Wu Jan 2013

Holocene Sedimentation On The Lanyang Plain And Adjacent Continental Shelf, Northwestern Taiwan, Chia-Yu Wu

Dissertations, Theses, and Masters Projects

The Lanyang Plain, along the northeastern Taiwan orogen, provides an excellent example of the tectonic and climatic controls on erosion and subsequent riverine sediment supply to the coastal ocean and deep sea. 12 deep borings on the Lanyang Plain and 2 long cores in Southern Okinawa Trough (MD12403, ODP1202), together with high-resolution seismic data on Ilan Shelf, provide a good record of the depositional history during Holocene, in both on-land and offshore areas. Based on these data, we find the sediment thickness reaches 216 m in Lanyang Plain, and the average sediment rate is estimated to be 3.6 Mt/yr - …

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Phytoplankton Growth Rates In The Ross Sea, Antarctica, Anna Ford Mosby Jan 2013

Phytoplankton Growth Rates In The Ross Sea, Antarctica, Anna Ford Mosby

Dissertations, Theses, and Masters Projects

The Ross Sea is a highly productive region of the Southern Ocean characterized by spatially variable distribution of phytoplankton, primarily Phaeocystis antarctica, but phytoplankton growth rates in the region have not been thoroughly investigated. Variability in growth rates was investigated from January to February 2012 on a cruise to the Ross Sea using two methods: 14C-isotopic tracer incubations and dilution experiments. Because all methods of measuring growth rates may not be appropriate in all systems due to errors inherent to each method, I assessed and compared the two methods for possible sources of error by examining the effect of extended …

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Wireless Electronic Scoring Of Kendo Competition Matches Using An Embedded System, Edward B. Hogan Jan 2013

Wireless Electronic Scoring Of Kendo Competition Matches Using An Embedded System, Edward B. Hogan

EWU Masters Thesis Collection

"This paper describes the wireless electronic system for the scoring of competition Kendo matches. This system is composed of an Arduino UNO microcontroller board with force sensing resistor pads located on the outside of the combatants Kendo armor. These pads sense the amount of force applied by each combatant as they strike their opponent. The system also utilizes Window Comparator Chips to determine if the strike is of sufficient force. If the force is sufficient the Arduino UN0 board reports the hit via a Bluetooth modem to a laptop. The program running on the laptop records the time of the …

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Fractal Dimension And Julia Sets, Robert Delorto Jan 2013

Fractal Dimension And Julia Sets, Robert Delorto

EWU Masters Thesis Collection

No abstract provided.

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Not All That Glitters Is Gold: The Effect Of Attention And Blogs On The Investors' Investing Behaviors, Nan Hu, Yi Dong, Ling Liu, Lee J. Yao Jan 2013

Not All That Glitters Is Gold: The Effect Of Attention And Blogs On The Investors' Investing Behaviors, Nan Hu, Yi Dong, Ling Liu, Lee J. Yao

Research Collection School Of Computing and Information Systems

This article investigates the relationship between a firm’s visibility in blogspaces, termed blog exposure, and the cross-sectional stock returns. We show that blog exposure is fundamentally different from the traditional media coverage, and securities with low blog exposure earn higher returns than stocks with high blog exposure. We further illustrate that such an effect is more prominent for stocks with low institutional ownership. Contrary to traditional media coverage, the return premium associated with blog exposure cannot be explained by either the illiquidity hypothesis or the investor recognition hypothesis based on the rational-agent framework. Instead, our results suggest that blog effect …

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Depairing Current Density In Cuprate Superconductors, Manlai Liang Jan 2013

Depairing Current Density In Cuprate Superconductors, Manlai Liang

Theses and Dissertations

We report a study of the depairing critical current density in the electron-doped infinite-layer Sr1-xLaxCuO2 and Nd2-xCexCuO4-\delta system. In this work, many new apparatuses were set up to measure the samples. Resistance-versus-temperature transition curves measured at high pulsed current densities show the classic proportionality between the transition-temperature shift and the two-thirds power of the applied current. The measurement provides an assessment of the superfluid density in the system, and a secondary route for obtaining the penetration depth purely through a transport measurements.

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