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2012

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Articles 12001 - 12030 of 12196

Full-Text Articles in Physical Sciences and Mathematics

Analysis Of Discrete Choice Probit Models With Structured Correlation Matrices, Bhaskara Ravi Jan 2012

Analysis Of Discrete Choice Probit Models With Structured Correlation Matrices, Bhaskara Ravi

Mathematics & Statistics Theses & Dissertations

Discrete choice models are very popular in Economics and the conditional logit model is the most widely used model to analyze consumer choice behavior, which was introduced in a seminal paper by McFadden (1974). This model is based on the assumption that the unobserved factors, which determine the consumer choices, are independent and follow a Gumbel distribution, widely known as the Independence of irrelevant Alternatives (IIA) assumption. Alternate models that relax IIA assumption are the Generalized Extreme Value (GEV) models, which allow dependency between unobserved factors. However, GEV models do not incorporate all dependency patterns, other choice behaviors such as …


Critical Assessment Of Outcomes In Acute Aortic Dissection (Type A) At A Community Hospital: A 10 Year Review, Timothy S. Misselbeck, James K. Wu Md, Stephen Deturk Ba, Michael F. Szwerc Md, Sanjay M. Mehta Md, Theodore G. Phillips Md, Gary W. Szydlowski Md, Raymond L. Singer Md Jan 2012

Critical Assessment Of Outcomes In Acute Aortic Dissection (Type A) At A Community Hospital: A 10 Year Review, Timothy S. Misselbeck, James K. Wu Md, Stephen Deturk Ba, Michael F. Szwerc Md, Sanjay M. Mehta Md, Theodore G. Phillips Md, Gary W. Szydlowski Md, Raymond L. Singer Md

Department of Surgery

No abstract provided.


Continuous And Smooth Images Of Sets, Krzysztof Ciesielski Jan 2012

Continuous And Smooth Images Of Sets, Krzysztof Ciesielski

Faculty & Staff Scholarship

This note shows that if a subset S of R is such that some continuous function f from R to R has the property "f[S] contains a perfect set," then some infinitely many times differentiable function g (from R to R) has the same property. Moreover, if f[S] is nowhere dense, then the g can have the stronger property "g[S] is perfect." The last result is used to show that it is consistent with ZFC (the usual axioms of set theory) that for each subset S of R of cardinality continuum there exists an infinitely many times differentiable function …


Functions Continuous On Twice Differentiable Curves, Discontinuous On Large Sets, Krzysztof Ciesielski Jan 2012

Functions Continuous On Twice Differentiable Curves, Discontinuous On Large Sets, Krzysztof Ciesielski

Faculty & Staff Scholarship

We provide a simple construction of a function F:R2-->R discontinuous on a perfect set P, while having continuous restrictions F|C for all twice differentiable curves C. In particular, F is separately continuous and linearly continuous. While it has been known that the projection \pi[P] of any such set P onto a straight line must be meager, our construction allows \pi[P] to have arbitrarily large measure. In particular, P can have arbitrarily large 1-Hausdorff measure, which is the best possible result in this direction, since any such P has Hausdorff dimension at most 1.


Geometric Graph Theory And Wireless Sensor Networks, Deniz Sarioz Jan 2012

Geometric Graph Theory And Wireless Sensor Networks, Deniz Sarioz

Dissertations, Theses, and Capstone Projects

In this work, we apply geometric and combinatorial methods to explore a variety of problems motivated by wireless sensor networks. Imagine sensors capable of communicating along straight lines except through obstacles like buildings or barriers, such that the communication network topology of the sensors is their visibility graph. Using a standard distributed algorithm, the sensors can build common knowledge of their network topology.

We first study the following inverse visibility problem: What positions of sensors and obstacles define the computed visibility graph, with fewest obstacles? This is the problem of finding a minimum obstacle representation of a graph. This minimum …


Photocatalytic Hydrogen Production At Titania-Supported Pt Nanoclusters That Are Derived From Surface-Anchored Molecular Precursors, Rony S. Khnayzer, Lucas B. Thompson, Mikhail Zamkov, Shane Ardo, Gerald J. Meyer, Catherine J. Murphy, Felix N. Castellano Jan 2012

Photocatalytic Hydrogen Production At Titania-Supported Pt Nanoclusters That Are Derived From Surface-Anchored Molecular Precursors, Rony S. Khnayzer, Lucas B. Thompson, Mikhail Zamkov, Shane Ardo, Gerald J. Meyer, Catherine J. Murphy, Felix N. Castellano

Physics and Astronomy Faculty Publications

Degussa P-25 TiO2 bearing surface-anchored Pt(dcbpy)Cl-2 [dcbpy = 4,4'-dicarboxylic acid-2,2'-bipyridine] prepared with systematically varied surface coverage produced Pt-0 nanoparticles under bandgap illumination in the presence of methanol hole scavengers. Energy-dispersive X-ray spectroscopy confirmed the presence of elemental platinum in the newly formed nanoparticles during scanning transmission electron microscopy (STEM) eleriments. According to the statistical analysis of numerous STEM images, the Pt-0 nanoclusters were distributed in a segregated manner throughout the titania surface, ranging in size from 1 to 3 nm in diameter. The final achieved nanoparticle size and net hydrogen production were determined as a function of the Pt(dcbpy)Cl-2 surface …


Acth Promotes Osteogenesis Of Rat Mesenchymal Stem Cells Through The Melanocortin-2 Receptor, Jodi F. Evans Ph.D., Sylvana Rodriguez, Louis Ragolia Jan 2012

Acth Promotes Osteogenesis Of Rat Mesenchymal Stem Cells Through The Melanocortin-2 Receptor, Jodi F. Evans Ph.D., Sylvana Rodriguez, Louis Ragolia

Faculty Works: BCES (1999-2023)

Adrenocorticotropin Hormone (ACTH) is an endocrine hormone that is secreted by the pituitary and stimulates the secretion of cortisol from the adrenal cortex. It is among the several melanocortin peptide hormones that are derived from proopiomelanocortin (POMC) such as α-melanocyte stimulating hormone (α-MSH), γ-MSH and the endorphins. ACTH is also produced by cells outside the central nervous system and has been found to play a role in osteogenesis. Using mesenchymal stem cells (MSC) obtained from bone marrow of the Wystar Kyoto (WKY) rat, we confirmed that ACTH increases osteogenesis in a dosedependent manner. Immunoblot of crude membrane fractions was used …


Reuse: Creating A Next Life For Common Items, Roslynn Brain, H. Waldbillig Jan 2012

Reuse: Creating A Next Life For Common Items, Roslynn Brain, H. Waldbillig

Environment and Society Faculty Publications

If you are looking for ways to save money and add creative flair to your daily life, reusing everyday items you are likely to throw away could be the answer! We produce an average of 4.4 pounds each of trash a day in the U.S., which amounts to 1,600 pounds per person each year (Environmental Protection Agency, 2011). This yearly waste produced by each one of us is more than the typical weight of a Bison, America’s largest land animal! Often overshadowed by recycling, reusing is a zero-impact technique for waste prevention. By using a product or item in its …


Fostering University-Wide Sustainable Behaviors Through Service Learning: A Classroom Transition From Theory To Real World Application, Roslynn Brain Jan 2012

Fostering University-Wide Sustainable Behaviors Through Service Learning: A Classroom Transition From Theory To Real World Application, Roslynn Brain

Environment and Society Faculty Publications

No abstract provided.


Sustainability Cultural Indicators, J. Callewaert, Roslynn Brain, L. C. Malan Jan 2012

Sustainability Cultural Indicators, J. Callewaert, Roslynn Brain, L. C. Malan

Environment and Society Faculty Publications

No abstract provided.


Vermicomposting! Sustain Your Life: Utah State University Extension Sustainability, Roslynn Brain, H. Waldbillig, K. Ladd, J. Greene Jan 2012

Vermicomposting! Sustain Your Life: Utah State University Extension Sustainability, Roslynn Brain, H. Waldbillig, K. Ladd, J. Greene

Environment and Society Faculty Publications

No abstract provided.


Stability Indices For Constrained Self-Adjoint Operators, Todd Kapitula, Keith Promislow Jan 2012

Stability Indices For Constrained Self-Adjoint Operators, Todd Kapitula, Keith Promislow

University Faculty Publications and Creative Works

A wide class of problems in the study of the spectral and orbital stability of dispersive waves in Hamiltonian systems can be reduced to understanding the so-called "energy spectrum", that is, the spectrum of the second variation of the Hamiltonian evaluated at the wave shape, which is constrained to act on a closed subspace of the underlying Hilbert space. We present a substantially simplified proof of the negative eigenvalue count for such constrained, self-adjoint operators, and extend the result to include an analysis of the location of the point spectra of the constrained operator relative to that of the unconstrained …


Coconuts And The Emergence Of Violence In Sulu: Beyond Resource Competitionpparadigms, Yancey Orr Jan 2012

Coconuts And The Emergence Of Violence In Sulu: Beyond Resource Competitionpparadigms, Yancey Orr

Environmental Science and Policy: Faculty Publications

No abstract provided.


Multi-Payload Measurement Of Transverse Velocity Shears In The Topside Ionosphere, E. T. Lundberg, P. M. Kintner, Kristina A. Lynch, M. R. Mella Jan 2012

Multi-Payload Measurement Of Transverse Velocity Shears In The Topside Ionosphere, E. T. Lundberg, P. M. Kintner, Kristina A. Lynch, M. R. Mella

Dartmouth Scholarship

Using a multi-payload sounding rocket mission, we present the first direct measurement of velocity shear in the topside auroral ionosphere. In regions of large, ∼200 mV/m, transient electric fields we directly measure differences in the plasma drift velocity. From these differences, shear frequencies reaching ±6Hz are measured. These directly measured shears are compared with the shear inferred from single payload measurements. It is shown this traditional measurement of shear overestimates the shear frequency by a factor of two for this event, highlighting the importance of the temporal component of near-DC electric field structures. Coincident with these strong fields and shears …


A Geophysical Investigation Of The Northeastern Rim Of The St. Martin Impact Structure, Manitoba, Canada, Vladimir B. Zivkovic Jan 2012

A Geophysical Investigation Of The Northeastern Rim Of The St. Martin Impact Structure, Manitoba, Canada, Vladimir B. Zivkovic

Theses and Dissertations

The St. Martin impact structure is a 40 Km diameter structure located in Manitoba, Canada lies in featureless, glaciated terrain lacking any surface expression of an impact structure. The age of the structure has been re-determined to range between 224.3 Ma to 241.4 Ma which nullified a previous hypothesis suggesting this impact was part of a multiple impact event. Within the proposed structural boundary two outcrops of Archean granite are present. The first outcrop is located in what has been identified as the central peak of the impact structure. The second outcrop lies along the northeastern boundary and is known …


Screen-Printing Of Ferrite Magnetic Nanoparticles Produced By Carbon Combustion Synthesis Of Oxides, Karen S. Martirosyan, Gamage Dannangoda, Eduard Galstyan, Dmitri Litvinov Jan 2012

Screen-Printing Of Ferrite Magnetic Nanoparticles Produced By Carbon Combustion Synthesis Of Oxides, Karen S. Martirosyan, Gamage Dannangoda, Eduard Galstyan, Dmitri Litvinov

Physics and Astronomy Faculty Publications and Presentations

The feasibility of screen-printing process of hard ferrite magnetic nanoparticles produced by carbon combustion synthesis of oxides (CCSO) is investigated. In CCSO, the exothermic oxidation of carbon generates a smolder thermal reaction wave that propagates through the solid reactant mixture converting it to the desired oxides. The complete conversion of hexaferrites occurs using reactant mixtures containing 11 wt. % of carbon. The BaFe12O19 and SrFe12O19 hexaferrites had hard magnetic properties with coercivity of 3 and 4.5 kOe, respectively. It was shown that the synthesized nanoparticles could be used to fabricate permanent magnet structures by consolidating them using screen-printing techniques.


Controlling Calibration Errors In Gravitational-Wave Detectors By Precise Location Of Calibration Forces, H. Daveloza, M Afrin Badhan, Mario C. Diaz, K. Kawabe, P. N. Konverski, M. Landry, R. L. Savage Jan 2012

Controlling Calibration Errors In Gravitational-Wave Detectors By Precise Location Of Calibration Forces, H. Daveloza, M Afrin Badhan, Mario C. Diaz, K. Kawabe, P. N. Konverski, M. Landry, R. L. Savage

Physics and Astronomy Faculty Publications and Presentations

We present results of finite element analysis simulations which could lead to more accurate calibration of interferometric gravitational wave detectors. Calibration and actuation forces applied to the interferometer test masses cause elastic deformation, inducing errors in the calibration. These errors increase with actuation frequency, and can be greater than 50% at frequencies above a few kilohertz. We show that they can be reduced significantly by optimizing the position at which the forces are applied. The Advanced LIGO [1] photon calibrators use a two-beam configuration to reduce the impact of local deformations of the test mass surface. The position of the …


A Data-Descriptive Feedback Framework For Data Stream Management Systems, Rafael J. Fernández Moctezuma Jan 2012

A Data-Descriptive Feedback Framework For Data Stream Management Systems, Rafael J. Fernández Moctezuma

Dissertations and Theses

Data Stream Management Systems (DSMSs) provide support for continuous query evaluation over data streams. Data streams provide processing challenges due to their unbounded nature and varying characteristics, such as rate and density fluctuations. DSMSs need to adapt stream processing to these changes within certain constraints, such as available computational resources and minimum latency requirements in producing results. The proposed research develops an inter-operator feedback framework, where opportunities for run-time adaptation of stream processing are expressed in terms of descriptions of substreams and actions applicable to the substreams, called feedback punctuations. Both the discovery of adaptation opportunities and the exploitation of …


Understanding The Emission From Semiconductor Nanoparticles, Beth Ann Manhat Jan 2012

Understanding The Emission From Semiconductor Nanoparticles, Beth Ann Manhat

Dissertations and Theses

This dissertation describes the synthesis and characterization of fluorescent semiconductor nanoparticles (NPs) in order to optimize their biomedical utility for imaging and sensing applications. While both direct and indirect bandgap semiconductor NPs have been studied, control over their emission properties vary. Quantum confinement (QC), which primarily controls the emission wavelength of nanosized semiconductors, dictates that as the size of semiconductor NPs decrease, the magnitude of the bandgap increases, resulting in changes in the observed emission wavelength: smaller NPs have a larger bandgap, and thus a bluer emission. However, surface, interfacial, or shell defects can act as non-radiative or radiative recombination …


Groundwater Surface Trends In The North Florence Dunal Aquifer, Oregon Coast, Usa, Sarah Rebecca Doliber Jan 2012

Groundwater Surface Trends In The North Florence Dunal Aquifer, Oregon Coast, Usa, Sarah Rebecca Doliber

Dissertations and Theses

The North Florence Dunal Aquifer is the only feasible source for drinking water for the coastal city of Florence, Oregon and Florence's Urban Growth Boundary. High infiltration rates and a shallow groundwater table leave the aquifer highly susceptible to contamination from septic tank effluent, storm runoff, chemical fertilizers and recreational ATV use throughout the dunes. Public interest in the quality and quantity of the aquifer water has been sparked since the City of Florence received a grant from the Environmental Protection Agency for a watershed protection and restoration project. Delineation of the shallow groundwater surface and its relationship to the …


Understanding Sand Mining On The Maha Oya: The Conflict Between Economic And Environmental Survival, Meredith Corea Talbert Jan 2012

Understanding Sand Mining On The Maha Oya: The Conflict Between Economic And Environmental Survival, Meredith Corea Talbert

Dissertations and Theses

River sand mining from the Maha Oya is the main source of income and a force that drives economic activity for residents along the river. This study takes place in Sri Lanka, there are three villages included in this project: Jambugaswatte, Janituspuraya and Thoppuwa. In Sri Lanka, sand serves as the main building material. It is used to make bricks, tiles, asphalt and concrete, therefore demanding a high market value. However, the over-extraction of sand comes along with significant environmental problems. These communities depend on the river in many ways and the health of the river directly corresponds to the …


Sustainability Education As A Framework For Enhancing Environmental Stewardship In Young Leaders: An Intervention At Tryon Creek Nature Day Camp, Andrea Nicole Lawrence Jan 2012

Sustainability Education As A Framework For Enhancing Environmental Stewardship In Young Leaders: An Intervention At Tryon Creek Nature Day Camp, Andrea Nicole Lawrence

Dissertations and Theses

UNESCO established Sustainability Education as a top priority when it declared 2005 - 2014 to be the global decade for sustainability. Sustainability education can be implemented in outdoor programs such as nature summer camps in order to build environmental stewardship and ecological literacy in counselors and campers. This study sought to determine the extent to which an ecology and leadership training given to assistant counselors at Tryon Creek State Natural Area day camp achieved the goals of sustainability education--for the assistant counselors to learn about ecology, develop stewardship attitudes and behaviors toward the environment, and become positive role models for …


Short-Term Plasticity At The Schaffer Collateral: A New Model With Implications For Hippocampal Processing, Andrew Hamilton Toland Jan 2012

Short-Term Plasticity At The Schaffer Collateral: A New Model With Implications For Hippocampal Processing, Andrew Hamilton Toland

Dissertations and Theses

A new mathematical model of short-term synaptic plasticity (STP) at the Schaffer collateral is introduced. Like other models of STP, the new model relates short-term synaptic plasticity to an interaction between facilitative and depressive dynamic influences. Unlike previous models, the new model successfully simulates facilitative and depressive dynamics within the framework of the synaptic vesicle cycle. The novelty of the model lies in the description of a competitive interaction between calcium-sensitive proteins for binding sites on the vesicle release machinery. By attributing specific molecular causes to observable presynaptic effects, the new model of STP can predict the effects of specific …


Long-Term Responses Of Phalaris Arundinacea And Columbia River Bottomland Vegetation To Managed Flooding, Tina Schantz Farrelly Jan 2012

Long-Term Responses Of Phalaris Arundinacea And Columbia River Bottomland Vegetation To Managed Flooding, Tina Schantz Farrelly

Dissertations and Theses

I sought to determine the effect of managed flooding on Phalaris arundinacea L. and other plant species distributions in a large wetland complex, Smith and Bybee Wetlands (SBW), in northwestern Oregon. Altered hydrology has reduced historically high spring flow and prematurely initiated the historic summer drying period at SBW. This alteration has increased the coverage of invasive plants (e.g., P. arundinacea) causing a decrease in native plant cover and thus degrading ecological functions. SBW managers installed a water control structure (WCS) between SBW and the Columbia Slough/River system to impound winter rainfall and thus approximate the ecological benefits that natural …


A Survey And Analysis Of Solutions To The Oblivious Memory Access Problem, Erin Elizabeth Chapman Jan 2012

A Survey And Analysis Of Solutions To The Oblivious Memory Access Problem, Erin Elizabeth Chapman

Dissertations and Theses

Despite the use of strong encryption schemes, one can still learn information about encrypted data using side channel attacks [2]. Watching what physical memory is being accessed can be such a side channel. One can hide this information by using oblivious simulation - hiding the true access pattern of a program. In this paper we will review the model behind oblivious simulation, attempt to formalize the problem and define a security game. We will review the major solutions pro- posed so far, the square root and hierarchical solutions, as well as propose a new variation on the square root solution. …


Controlling Nanoparticles Formation In Molten Metallic Bilayers By Pulsed-Laser Interference Heating, Mikhail Khenner, Sagar Yadavali, Ramki Kalyanaraman Jan 2012

Controlling Nanoparticles Formation In Molten Metallic Bilayers By Pulsed-Laser Interference Heating, Mikhail Khenner, Sagar Yadavali, Ramki Kalyanaraman

Mathematics Faculty Publications

The impacts of the two-beam interference heating on the number of core-shell and embedded nanoparticles and on nanostructure coarsening are studied numerically based on the non-linear dynamical model for dewetting of the pulsed-laser irradiated, thin (< 20 nm) metallic bilayers. The model incorporates thermocapillary forces and disjoining pressures, and assumes dewetting from the optically transparent substrate atop of the reflective support layer, which results in the complicated dependence of light reflectivity and absorption on the thicknesses of the layers. Stabilizing thermocapillary effect is due to the local thickness-dependent, steady- state temperature profile in the liquid, which is derived based on the mean substrate temperature estimated from the elaborate thermal model of transient heating and melting/freezing. Linear stability analysis of the model equations set for Ag/Co bilayer predicts the dewetting length scales in the qualitative agreement with experiment.


Summary Tables: City Of Virginia Beach, Virginia Shoreline Inventory Report, Marcia Berman, Harry Berquist, Sharon Killeen, Carl Hershner, Karinna Nunez, Karen Reay, Tamia Rudnicky, Daniel E. Schatt Jan 2012

Summary Tables: City Of Virginia Beach, Virginia Shoreline Inventory Report, Marcia Berman, Harry Berquist, Sharon Killeen, Carl Hershner, Karinna Nunez, Karen Reay, Tamia Rudnicky, Daniel E. Schatt

Reports

The Shoreline Inventory Summary Tables quantify observed conditions based on river systems, such as the combined length of linear features (e.g. shoreline miles surveyed, miles of bulkhead and revetment), the total number of point features (e.g. docks, boathouses, boat ramps) & total acres of polygon features (tidal marshes).


Summary Tables: 2012 Henrico County, Virginia Shoreline Inventory, Marcia Berman, Harry Berquist, Sharon Killeen, Carl H. Hershner, Karinna Nunez, Karen Reay, Tamia Rudnicky, Daniel E. Schatt Jan 2012

Summary Tables: 2012 Henrico County, Virginia Shoreline Inventory, Marcia Berman, Harry Berquist, Sharon Killeen, Carl H. Hershner, Karinna Nunez, Karen Reay, Tamia Rudnicky, Daniel E. Schatt

Reports

The Shoreline Inventory Summary Tables quantify observed conditions based on river systems, such as the combined length of linear features (e.g. shoreline miles surveyed, miles of bulkhead and revetment), the total number of point features (e.g. docks, boathouses, boat ramps) & total acres of polygon features (tidal marshes).


On The Influence Of Damping In Hyperbolic Equations With Parabolic Degeneracy, Ralph Saxton, Katarzyna Saxton Dec 2011

On The Influence Of Damping In Hyperbolic Equations With Parabolic Degeneracy, Ralph Saxton, Katarzyna Saxton

Ralph Saxton

This paper examines the effect of damping on a nonstrictly hyperbolic 2x2 system. It is shown that the growth of singularities is not restricted as in the strictly hyperbolic case where dissipation can be strong enough to preserve the smoothness of solutions globally in time. Here, irrespective of the stabilizing properties of damping, solutions are found to break down in finite time on a line where two eigenvalues coincide in state space.


Spatial Graphs With Local Knots, Ramin Naimi, Erica Flapan, Blake Mellor Dec 2011

Spatial Graphs With Local Knots, Ramin Naimi, Erica Flapan, Blake Mellor

Ramin Naimi

It is shown that for any locally knotted edge of a 3-connected graph in $S^3$, there is a ball that contains all of the local knots of that edge and is unique up to an isotopy setwise fixing the graph. This result is applied to the study of topological symmetry groups of graphs embedded in $S^3$.