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2007

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Articles 91 - 120 of 5716

Full-Text Articles in Physical Sciences and Mathematics

Identification Of The Possible Defect States In Poly(3-Hexylthiophene) Thin Films, D.-Q. Feng, A. N. Caruso, Yaroslav B. Losovyj, D. L. Schulz, Peter A. Dowben Dec 2007

Identification Of The Possible Defect States In Poly(3-Hexylthiophene) Thin Films, D.-Q. Feng, A. N. Caruso, Yaroslav B. Losovyj, D. L. Schulz, Peter A. Dowben

Peter Dowben Publications

The possible origins of a low density of defect states within the highest occupied molecular orbital to lowest unoccupied molecular orbital gap are suggested for regioregular poly(3- hexylthiophene). A number of chemical defects, impurities, and structural defects could contribute to features in photoemission for regioregular poly(3-hexylthiophene), observed within the highest occupied molecular orbital to lowest unoccupied molecular orbital gap of regioregular poly(3-hexylthiophene).


Spitzer Irs Observations Of Seyfert 1.8 And 1.9 Galaxies: A Comparison With Seyfert 1 And Seyfert 2, R. P. Deo, D. M. Crenshaw, S. B. Kraemer, M. Dietrich, Moshe Elitzur, H. Teplitz, T. J. Turner Dec 2007

Spitzer Irs Observations Of Seyfert 1.8 And 1.9 Galaxies: A Comparison With Seyfert 1 And Seyfert 2, R. P. Deo, D. M. Crenshaw, S. B. Kraemer, M. Dietrich, Moshe Elitzur, H. Teplitz, T. J. Turner

Physics and Astronomy Faculty Publications

We present Spitzer mid-infrared spectra of 12 Seyfert 1.8 and 1.9 galaxies over the 5-38 μm region. We compare the spectral characteristics of this sample to those of 58 Seyfert 1 and 2 galaxies from the Spitzer archives. An analysis of the spectral shapes, the silicate 10 μm feature and the emission-line fluxes have enabled us to characterize the mid-IR properties of Seyfert 1.8/1.9s. We find that the EWs of the 10 μm silicate feature are generally weak in all Seyfert galaxies, as previously reported by several studies. The few Seyfert galaxies in this sample that show …


Multijet Production At Low XBj In Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi Dec 2007

Multijet Production At Low XBj In Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi

Faculty Publications

Inclusive dijet and trijet production in deep inelastic ep scattering has been measured for 10 < Q2 < 100 GeV2 and low Bjorken x, 10-4 < xBj < 10-2. The data were taken at the HERA ep collider with centre-of-mass energy sqrt(s) = 318 GeV using the ZEUS detector and correspond to an integrated luminosity of 82 pb-1. Jets were identified in the hadronic centre-of-mass (HCM) frame using the kT cluster algorithm in the longitudinally invariant inclusive mode. Measurements of dijet and trijet differential cross sections are presented as functions of Q2, xBj, jet transverse energy, and jet pseudorapidity. As a further examination of low-xBj dynamics, multi-differential cross sections as functions of the jet correlations in transverse momenta, azimuthal angles, and pseudorapidity are also presented. Calculations at O (αs3) generally describe the trijet data well and improve the description of the dijet data compared to the calculation at O (αs2). © 2007 Elsevier B.V. All rights reserved.


Learning Languages From Positive Data And A Limited Number Of Short Counterexamples, Sanjay Jain, Efim Kinber Dec 2007

Learning Languages From Positive Data And A Limited Number Of Short Counterexamples, Sanjay Jain, Efim Kinber

School of Computer Science & Engineering Faculty Publications

We consider two variants of a model for learning languages in the limit from positive data and a limited number of short negative counterexamples (counterexamples are considered to be short if they are smaller than the largest element of input seen so far). Negative counterexamples to a conjecture are examples which belong to the conjectured language but do not belong to the input language. Within this framework, we explore how/when learners using n short (arbitrary) negative counterexamples can be simulated (or simulate) using least short counterexamples or just ‘no’ answers from a teacher. We also study how a limited number …


Hybrid Image/Model Based Gaze-Contingent Rendering, Hunter Murphy Dec 2007

Hybrid Image/Model Based Gaze-Contingent Rendering, Hunter Murphy

All Dissertations

A non-isotropic hybrid image/model based gaze-contingent rendering technique utilizing ray casting on a GPU is discussed. Empirical evidence derived from human subject experiments indicates an inverse relationship between a peripherally degraded scene's high-resolution inset size and mean search time, a trend consistent with existing image-based and model-based techniques. In addition, the data suggest that maintaining a target's silhouette edges decreases search times when compared to targets with degraded edges. Benefits of the hybrid technique include simplicity of design and parallelizability, both conducive to GPU implementation.


Development Of Fullerene Based Sturctures For Photovoltaic And Electronic Applications, Amit Palkar Dec 2007

Development Of Fullerene Based Sturctures For Photovoltaic And Electronic Applications, Amit Palkar

All Dissertations

Solar energy can be envisioned as a long term alternative to rapidly depleting fossil fuels. The energy from the sun can be harnessed by constructing donor-acceptor (D-A) type devices where the incident photon induces the transfer of an electron from the donor to the acceptor. If recombination is prevented, this electron can then be channeled through an external circuit, thus leading to the generation of photocurrent. Porphyrins, which are the naturally occurring pigments in photosynthesis, have been widely established as donors while fullerenes, such as C60 and C70 , due to their unique electron accepting properties, have been …


Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges, And Bars, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula Dec 2007

Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges, And Bars, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula

Physics & Astronomy: Faculty Publications

We investigate formation and evolution of galactic disks immersed in assembling live DM halos. Models have been evolved from cosmological initial conditions and represent the collapse of an isolated density perturbation. The baryons include gas participating in star formation (SF) and stars with the energy feedback onto the ISM. We find that (1) the triaxial halo figure tumbling is insignificant and the angular momentum (J) is channeled into the internal circulation, while the baryonic collapse is stopped by the centrifugal barrier; (2) density response of the (disk) baryons is out of phase with DM, thus washing out the …


Lithium-Conducting Ionic Melt Electrolytes From Oligomeric Ethylene Glycols: Synthesis And Characterization, Boutros Hallac Dec 2007

Lithium-Conducting Ionic Melt Electrolytes From Oligomeric Ethylene Glycols: Synthesis And Characterization, Boutros Hallac

All Dissertations

Commercial lithium ion cells consist of electrolytes that undergo salt concentration polarization which is acute upon high discharge currents. This type of polarization occurs as a result of the mobility of more than one ionic species in the presence of an electric field. One way to overcome it is by employing a material that would allow the mobility of one ionic species. This thesis will describe the synthesis and characterization of several fluorosulfonimide and fluorosulfonate based ionic liquids/melts as electrolytes having lithium as the only mobile ion. These materials were prepared by the nucleophilic addition reaction of a deprotonated polyether …


Thermodynaimic Study Of Nucleic Acids Recognition By Aminoglycosides , Hongjuan Xi Dec 2007

Thermodynaimic Study Of Nucleic Acids Recognition By Aminoglycosides , Hongjuan Xi

All Dissertations

ABSTRACT


Since the origin of first aminoglycosides antibiotics, streptomycin, isolated by Selman Waksman about 60 years ago, a number of aminoglycosides antibiotics were discovered to treat different infections. Neomycin class aminoglycosides were found to originally target the A site 16S rRNA in the 30S subunit of the ribosome within the Gram-negative bacteria. In addition to its antibacterial effect, aminoglycosides were also found to binding to various other viral RNA structures such as TAR and RRE of HIV, Group I introns and hammerhead ribozyme, implying its potential to be used as antiviral reagent.

Furthermore, previous studies in our laboratory discovered a …


Water Quality Dynamics Of Lake James In The Catawba River Basin Of North Carolina, Susan Stokes Dec 2007

Water Quality Dynamics Of Lake James In The Catawba River Basin Of North Carolina, Susan Stokes

All Dissertations

Lake James is the uppermost hydropower reservoir in the Catawba River drainage in North Carolina. The Lake James Assessment (LJA) was a descriptive study initiated between Clemson University and Duke Energy Corporation to explore the physical, chemical and biological dynamics of this oligotrophic reservoir from spring 1997 through fall 1999 (Schindler 1997). The goals of this study were to ascertain the primary drivers for the chemical dynamics of Lake James, to assess the quantities of constituents entering and leaving the reservoir, where these chemicals were incorporated within the reservoir basins, and to evaluate the efficacy of the LJA chemical budget …


Studies Of The Stability And Potential Applications Of Pyrrolidinofullerenes And Other Fullerene Derivatives, Olena Lukoyanova Dec 2007

Studies Of The Stability And Potential Applications Of Pyrrolidinofullerenes And Other Fullerene Derivatives, Olena Lukoyanova

All Dissertations

Over the last decade, the variety of chemically modified fullerenes and their potential applications has increased significantly. Among fullerene derivatives, pyrrolidinofullerenes are one of the most widely synthesized types since they can be easily and efficiently obtained via simple reactions from both empty and endohedral fullerenes. Although fullerenes in general and pyrrolidinofullerenes in particular have been considered for numerous applications in electronic and optoelectronic devices, photovoltaics, medicinal chemistry, etc., their potential application in the evolving field of molecular electronics has not been extensively explored. The envisioned role of the fullerenes usually involves storage or transport of electrons. Therefore, studies of …


Issues In Model Selection, Minimax Estimation, And Censored Data Analysis, Meng Zhao Dec 2007

Issues In Model Selection, Minimax Estimation, And Censored Data Analysis, Meng Zhao

All Dissertations

In this dissertation, we address several research problems in statistical inference. We obtain results in the following four directions: linear model selection, minimax estimation of linear functionals, Bayes type estimators for the survival functions based on right censored data, and estimation of survival functions based on doubly censored data.


Diversity And Abundance Of Ants At Forest Edges , Eric Paysen Dec 2007

Diversity And Abundance Of Ants At Forest Edges , Eric Paysen

All Dissertations

Fragmented habitats are a common result of human activities that involve the clearing of native vegetation for various land uses. Habitat fragmentation has two primary and inseparable components: habitat loss and insularization. Landscape-level connectivity in fragmented habitats is diminished for many species, and edge characteristics become more important as the edge-to-interior ratio increases. The study of the effects of edges on biodiversity has compelled ecologists to study them for over a century and has influenced the design and management of natural preserves. Invasion of habitats by non-native species is a phenomenon that coincides with the increased human activity typical of …


Influence Of Mercury-Dissolved Organic Matter (Dom) Complexation On Toxicity In Natural Waters, Christina Mcnaughton Dec 2007

Influence Of Mercury-Dissolved Organic Matter (Dom) Complexation On Toxicity In Natural Waters, Christina Mcnaughton

All Dissertations

Global industrialization, coupled with a large biogeochemical cycle that moves mercury through the environment, has resulted in higher mercury concentrations being detected in many environmental compartments. Although the presence of mercury in each compartment has the potential to elicit toxicity, mercury found in natural waters provides the greatest risk, due to the various reactions it can undergo, resulting in a plethora of different species.
Due to the fact that mercury contamination in aquatic systems has the potential to bioaccumulate and biomagnify up the food chain and cause toxicity, understanding the behavior of mercury in these systems is imperative in the …


Measurement Of (Anti)Deuteron And (Anti)Proton Production In Dis At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi Dec 2007

Measurement Of (Anti)Deuteron And (Anti)Proton Production In Dis At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi

Faculty Publications

The first observation of (anti)deuterons in deep inelastic scattering at HERA has been made with the ZEUS detector at a centre-of-mass energy of 300-318 GeV using an integrated luminosity of 120 pb-1. The measurement was performed in the central rapidity region for transverse momentum per unit of mass in the range 0.3 < pT / M < 0.7. The particle rates have been extracted and interpreted in terms of the coalescence model. The (anti)deuteron production yield is smaller than the (anti)proton yield by approximately three orders of magnitude, consistent with the world measurements. © 2007 Elsevier B.V. All rights reserved.


Charge Effects In Bilayer Electric Transport, Christopher Czech Dec 2007

Charge Effects In Bilayer Electric Transport, Christopher Czech

All Theses

The mathematical isomorphism between the layer index in a bilayer system and the spin index in a spin-polarized system is used to draw an analogy between phenomena that occur in the two systems as a result of the electron-electron (e-e) interaction. First, the classical case of the Coulomb drag, a phenomenon resulting from momentum transfer through e-e collisions, is reviewed for both bilayer systems and spin-polarized systems. Then, the spin-backflow phenomenon, a result of the interaction-induced changes in the local quasiparticle energy that affects the charge transport in spin-polarized systems is presented. Finally, the iso-spin correlation is exploited to establish …


Solid Phase Crystallization Of Vanadium Dioxide Thin Films And Characterization Through Scanning Electron Microscopy, Felipe Rivera Dec 2007

Solid Phase Crystallization Of Vanadium Dioxide Thin Films And Characterization Through Scanning Electron Microscopy, Felipe Rivera

Theses and Dissertations

Crystalline films of vanadium dioxide were obtained through thermal annealing of amorphous vanadium dioxide thin films sputtered on silicon dioxide. An annealing process was found that yielded polycrystalline vanadium dioxide thin films, semi-continuous thin films, and films of isolated single-crystal particles. Orientation Imaging Microscopy (OIM) was used to characterize and study the phase and the orientation of the vanadium dioxide crystals obtained, as well as to diferentiate them from other vanadium oxide stoichiometries that may have formed during the annealing process. There was no evidence of any other vanadium oxides present in the prepared samples. Indexing of the crystals for …


Geochemical Reconstruction Of Late Holocene Drainage And Mixing In Kluane Lake, Yukon Territory, Janice Brahney, John J. Clague, Brian Menounos, Thomas W. D. Edwards Dec 2007

Geochemical Reconstruction Of Late Holocene Drainage And Mixing In Kluane Lake, Yukon Territory, Janice Brahney, John J. Clague, Brian Menounos, Thomas W. D. Edwards

Watershed Sciences Faculty Publications

The level of Kluane Lake in southwest Yukon Territory, Canada, has fluctuated tens of metres during the late Holocene. Contributions of sediment from different watersheds in the basin over the past 5,000 years were inferred from the elemental geochemistry of Kluane Lake sediment cores. Elements associated with organic material and oxyhydroxides were used to reconstruct redox fluctuations in the hypolimnion of the lake. The data reveal complex relationships between climate and river discharge during the late Holocene. A period of influx of Duke River sediment coincides with a relatively warm climate around 1,300 years BP. Discharge of Slims River into …


Reed-Solomon Codes Construction & Decoding, Samuel J. Parsons Dec 2007

Reed-Solomon Codes Construction & Decoding, Samuel J. Parsons

Honors Capstones

Capstone submitted as a graduation requirement for the BSU Honors Program.


How To Hunt A Wild Neutrino, Janet Conrad Dec 2007

How To Hunt A Wild Neutrino, Janet Conrad

IMSA Great Minds Program ®

Of all of the particles which make up matter, the neutrino is the most mysterious. Remnants of the big bang, neutrinos are everywhere -- up in your attic, out in the cornfields, deep in the farthest galaxies. Catching them has always been a problem. But recently we have discovered one of their tricks. They can change their spots -- from one type into another! This talk will discuss neutrinos, how to catch them, and in the context of the research at Fermilab.


Small-Scale X-Ray Variability In The Cassiopeia A Supernova Remnant, Daniel J. Patnaude, Robert A. Fesen Dec 2007

Small-Scale X-Ray Variability In The Cassiopeia A Supernova Remnant, Daniel J. Patnaude, Robert A. Fesen

Dartmouth Scholarship

A comparison of X-ray observations of the Cassiopeia A supernova remnant taken in 2000, 2002, and 2004 with the Chandra ACIS-S3 reveals the presence of several small-scale features (≤10'') that exhibit significant intensity changes over a 4 yr time frame. Here we report on the variability of six features, four of which show count rate increases from ~10% to over 90%, and two of which show decreases of ~30%-40%. While extracted 1-4.5 keV X-ray spectra do not reveal gross changes in emission-line strengths, spectral fits using nonequilibrium-ionization, metal-rich plasma models indicate increased or decreased electron temperatures for features showing increasing …


Measurement Of The Parameter Kappa, And Reevaluation Of Kappa For Small To Moderate Earthquakes At Seismic Stations In The Vicinity Of Yucca Mountain, Nevada, Glenn Biasi, John G. Anderson, Amy J. Smiecinski, Nevada Seismological Laboratory Dec 2007

Measurement Of The Parameter Kappa, And Reevaluation Of Kappa For Small To Moderate Earthquakes At Seismic Stations In The Vicinity Of Yucca Mountain, Nevada, Glenn Biasi, John G. Anderson, Amy J. Smiecinski, Nevada Seismological Laboratory

Publications (YM)

We address two primary questions. First, what are the values of seismic spectral decay parameter kappa at stations on and around Yucca Mountain. Second, can small and/or moderate earthquakes provide estimates of kappa that are valid for conditions of strong ground motion.


College Of Engineering Senior Design Competition Fall 2007, University Of Nevada, Las Vegas Dec 2007

College Of Engineering Senior Design Competition Fall 2007, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge.

The senior design competition helps to focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects …


Benthic Macroinvertebrate Exploration In The Rumford River Dec 2007

Benthic Macroinvertebrate Exploration In The Rumford River

Watershed Access Lab Projects

The students of Qualters Middle School performed a study called “Benthic Macroinvertebrate Exploration in the Rumford River”. The study was conducted on October 16, 2007 in Mansfield, Massachusetts. The study location consisted of one site located at 143 Chauncy Street.

The purpose of this study was to introduce benthic macroinvertebrates and their role as indicators for evaluating stream water quality. Students utilized state of the art methods and techniques during all aspects of this study.

The Rumford River is listed on the Environmental Protection Agencies (EPA) National Priority List (NPL). The river was polluted with dioxins, furans and phenols by …


Comparative Nutrient Data For Two Locations On The Marstons Mills River Dec 2007

Comparative Nutrient Data For Two Locations On The Marstons Mills River

Watershed Access Lab Projects

On October 30, 2007, we deployed water samplers at two locations along the Marstons Mills River: River Road and Hyrdo Dam/Route 28. We programmed a Sigma at each location to take a water sample each hour for 24 hours, to determine the amount of dissolved nutrients in the water in the course of one day. When compared to the discharge at each site, we found that the Hydro Dam location moved nearly 117 000 000 liters of water, 10 000 grams of phosphorus, and 25 000 grams of nitrogen-nitrate each day. Only a short distance upstream, the River Road location …


How Healthy Is Furnace Brook Dec 2007

How Healthy Is Furnace Brook

Watershed Access Lab Projects

Located across the street from the High school is Furnace Brook. Mike Gilbert and I are conducting an independent Study to determine the relative health of the Furnace Brook. This small stream is a tributary of the South River in Marshfield, Ma. To access the health will we be using a macro-invertebrate biological index as our primary tool? We will also be conducting a riparian survey as well as both a stream profile and flow. To start with we scouted the watershed using both aerial photos and Google earth. After driving to several potential areas we designated three sample sites: …


Rumford River Monitoring Project Dec 2007

Rumford River Monitoring Project

Watershed Access Lab Projects

Land use within a watershed can negatively impact water quality. Students investigated these impacts by collecting water samples at one sample site along the Rumford River at Route 123, Norton, MA. These samples were analyzed for phosphorus and nitrogen levels, as well as temperature and dissolved oxygen. Results of these tests are as follows:

The greatest potential impacts come from run off. Most of the land around the Rumford River has been developed for residential housing. These houses have septic systems for waste disposal. The TCP golf course is also located near the Norton Reservoir. Potential sources of nitrogen come …


Palmer River Water Discharge And Nutrient Study Dec 2007

Palmer River Water Discharge And Nutrient Study

Watershed Access Lab Projects

Can significant differences in Discharge and Nutrient concentration & load be determined or inferred for the Palmer River? Students studied 2 sites. These were located at Wilmarth Bridge Road (just off of Route 44) and at Reed Street (further south & downstream). Between the 2 sites are a few farms as well as a golf course. It is possible that runoff from these 2 sources has influenced the amount of phosphates &/or nitrates found in the Palmer River. Most Primary & Secondary habitat characteristics were the same for both sites; though Reed Street exhibited more variations

Students collected data on …


Rivernet Watershed Access Lab Program Overview - Dec. 2007, Kevin Curry Dec 2007

Rivernet Watershed Access Lab Program Overview - Dec. 2007, Kevin Curry

Watershed Access Lab Projects

Brief overview of the RiverNet Watershed Access program - its history and the achievements of the many participating teachers and students from throughout Southeastern Massachusetts.


Improving Information Security Management In Nonprofit Organisations With Action, Mark Carey-Smith, Karen Nelson, Lauren May Dec 2007

Improving Information Security Management In Nonprofit Organisations With Action, Mark Carey-Smith, Karen Nelson, Lauren May

Australian Information Security Management Conference

Information security is vital for protecting important assets of organisations, including the information resources and the organisation’s reputation. In Australia, the nonprofit sector makes a significant contribution to society but is under represented in the information security literature. This paper describes research in progress that is investigating and improving information security management in some nonprofit organisations (NPOs), which incorporates a participatory action research methodology. This approach will enhance the skill set likely to be present in Australian nonprofit organisations, producing a more sustainable solution, as well as contributing to the open literature. The Technology Acceptance Model will be utilised as …