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2007

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Articles 2341 - 2370 of 6758

Full-Text Articles in Physical Sciences and Mathematics

Environmental Risk Assessment Of Groundwater Recharge In Liwa Aquifer, Entisar Salem Al-Katheeri Jun 2007

Environmental Risk Assessment Of Groundwater Recharge In Liwa Aquifer, Entisar Salem Al-Katheeri

Theses

The Abu Dhabi Emirate has witnessed a remarkable development in the various aspects of life during the last three decades. Such rapid development imposes a tremendous pressure on natural resources including water. Conventional water resources in the Emirate are limited. The surface water is almost absent due to the scarcity and randomness of rainfall coupled with the prevailing arid conditions and high evaporation rates. In addition, groundwater is mostly brackish and non-renewable. Over-pumping practices have resulted into a severe decline in the groundwater levels and quality. A large portion of the freshwater demands in the Abu Dhabi Emirate is covered …


Introduction Of A New Construct: The Conceptual Tool "Flexibility", Mette Andresen Jun 2007

Introduction Of A New Construct: The Conceptual Tool "Flexibility", Mette Andresen

The Mathematics Enthusiast

This paper presents a new construct: the conceptual tool ‘Flexibility’. The construct was a result of an attempt to extract experiences of teaching and learning with the use of laptops. It was further developed and refined on the basis of four small-scale teaching experiments. The teaching experiments, being part of a development project in upper secondary school mathematics, investigated the use of laptops for teaching differential equations from a modeling point of view. The research was double-aimed: one objective was to conclude the project with some recommendations for the design of teaching, in the form of guidelines suitable for a …


Looking Back At The Beginning: Critical Thinking In Solving Unrealistic Problems, Mark Applebaum, Roza Leikin Jun 2007

Looking Back At The Beginning: Critical Thinking In Solving Unrealistic Problems, Mark Applebaum, Roza Leikin

The Mathematics Enthusiast

We believe that problem-solving skills engage critical thinking at every phase of problem solution. In this research a special attention is given to the fist phase - "understanding the problem". We consider this phase as a continuation of all the previous mathematical experience, in which understanding of new problems requires "looking back" at those solved in the past. Evaluation of the givens in the problem sometimes allows immediate solution whereas in other cases it shows that solution does not exist. We found that it is not easy for mathematics teachers to discover that a problem includes contradictory (i.e. unrealistic) conditions. …


Geophysical And Hydrogeological Studies Of Al-Foah Area, North Al Ain, United Arab Emirates (Uae), Sameh Yahyia Ali Suleiman Jun 2007

Geophysical And Hydrogeological Studies Of Al-Foah Area, North Al Ain, United Arab Emirates (Uae), Sameh Yahyia Ali Suleiman

Theses

No abstract provided.


Uniform Estimates For Eulerian-Lagrangian Methods For Singularly Perturbed Time-Dependent Problems, Hong Wang, Kaixin Wang Jun 2007

Uniform Estimates For Eulerian-Lagrangian Methods For Singularly Perturbed Time-Dependent Problems, Hong Wang, Kaixin Wang

Faculty Publications

We prove a priori optimal-order error estimates in a weighted energy norm for several Eulerian–Lagrangian methods for singularly perturbed, time-dependent convection-diffusion equations with full regularity. The estimates depend only on certain Sobolev norms of the initial and right-hand side data, but not on ε or any norm of the true solution, and so hold uniformly with respect to ε. We use the interpolation of spaces and stability estimates to derive an ε-uniform estimate for problems with minimal or intermediate regularity, where the convergence rates are proportional to certain Besov norms of the initial and right-hand side data.


Southeast Florida Coral Reef Evaluation And Monitoring Project 2006 Year 4 Final Report, Jennifer Wheaton, Carl Beaver, Sandra Brooks, Michael Callahan, Shannon Wade, Jeff Beal, Chantal Collier, Laura Herren, Jamie Monty, David S. Gilliam, Vanessa I. P. Brinkhuis, Daniel P. Fahy, Shaun M. Gill, Lindsey Habakuk Klink, M. A. Philips, Nicole R. Stephens, Brian K. Walker, Joanna C. Walczak, Richard E. Dodge, Tim Mcintosh, Steven Blair, Kenneth Banks, Louis E. Fisher, David Stout, Joe Ligas, Janet Phipps Jun 2007

Southeast Florida Coral Reef Evaluation And Monitoring Project 2006 Year 4 Final Report, Jennifer Wheaton, Carl Beaver, Sandra Brooks, Michael Callahan, Shannon Wade, Jeff Beal, Chantal Collier, Laura Herren, Jamie Monty, David S. Gilliam, Vanessa I. P. Brinkhuis, Daniel P. Fahy, Shaun M. Gill, Lindsey Habakuk Klink, M. A. Philips, Nicole R. Stephens, Brian K. Walker, Joanna C. Walczak, Richard E. Dodge, Tim Mcintosh, Steven Blair, Kenneth Banks, Louis E. Fisher, David Stout, Joe Ligas, Janet Phipps

Marine & Environmental Sciences Faculty Reports

No abstract provided.


Structural Analysis Of Csos1a And The Protein Shell Of The Halothiobacillus Neapolitanus Carboxysome, Yingssu Tsai, Michael R. Sawaya, Gordon C. Cannon, Fei Cai, Eric B. Williams, Sabine Heinhorst, Cheryl A. Kerfeld, Todd O. Yeates Jun 2007

Structural Analysis Of Csos1a And The Protein Shell Of The Halothiobacillus Neapolitanus Carboxysome, Yingssu Tsai, Michael R. Sawaya, Gordon C. Cannon, Fei Cai, Eric B. Williams, Sabine Heinhorst, Cheryl A. Kerfeld, Todd O. Yeates

Faculty Publications

The carboxysome is a bacterial organelle that functions to enhance the efficiency of CO2 fixation by encapsulating the enzymes ribulose bisphosphate carboxylase/ oxygenase (RuBisCO) and carbonic anhydrase. The outer shell of the carboxysome is reminiscent of a viral capsid, being constructed from many copies of a few small proteins. Here we describe the structure of the shell protein CsoS1A from the chemoautotrophic bacterium Halothiobacillus neapolitanus. The CsoS1A protein forms hexameric units that pack tightly together to form a molecular layer, which is perforated by narrow pores. Sulfate ions, soaked into crystals of CsoS1A, are observed in the pores of the …


Optimal Foraging In Eastern Fox Squirrel: Food Size Matters For A Generalist Forager, Robert Tatina Jun 2007

Optimal Foraging In Eastern Fox Squirrel: Food Size Matters For A Generalist Forager, Robert Tatina

The Prairie Naturalist

Classical optimal foraging theory (OFT) predicts that an animal forages optimally when it chooses foods with the highest energy benefit or minimizes time searching for and handling food. r evaluated OFT by presenting eastern fox squirrel (Sciurus niger) multiple food items (i.e., sunflower seeds and • fruits) in various density combinations. When the choice was between foods of equal energy benefits but different costs, they chose forage items with greater costs, seemingly not foraging optimally. However, individuals showed a partial preference for food items which minimized search time, but not handling time. The eastern fox squirrel also was …


Marshes-In Photos And Words. Review Of Marshes: The Disappearing Edens By Bill Burt, Douglas H. Johnson Jun 2007

Marshes-In Photos And Words. Review Of Marshes: The Disappearing Edens By Bill Burt, Douglas H. Johnson

The Prairie Naturalist

Bill Burt has done it again. The author of two superbly illustrated books (Shadowbirds and Rare and Elusive Birds of North America) that were reviewed earlier in this journal, Burt has returned with another excellent book, this one focusing on marshes. Like his earlier books, Marshes features wonderful close-up views of many hard-to-photograph birds. Here, in addition, are grand images of marsh landscapes and other marsh denizens, especially plants. Burt best characterizes his own book, which he intends as "an evocation and exploration, rather than a catalog of marshland life." He tells of his 30 years spent prowling …


Notes On Black-Footed Ferret Detectability And Behavior, David S. Jachowski Jun 2007

Notes On Black-Footed Ferret Detectability And Behavior, David S. Jachowski

The Prairie Naturalist

Despite over two decades of recovery efforts, the black-footed ferret (Mustela nigripes) remains one of the least understood and most critically endangered mammals in North America. Once extinct in the wild, over 2,400 captive-born individuals of black-footed ferret (hereafter referred to as ferret) have been released at 13 reintroduction sites ranging from northern Montana to Chihuahua, Mexico, since 1991. However, ferret populations currently are considered to be self-sustaining at only two sites in South Dakota and a single site in Wyoming (United States Fish and Wildlife Service 2006). To understand why ferret recovery is not succeeding at a …


Epsilon-Unfolding Orthogonal Polyhedra, Mirela Damian, Robin Flatland, Joseph O'Rourke Jun 2007

Epsilon-Unfolding Orthogonal Polyhedra, Mirela Damian, Robin Flatland, Joseph O'Rourke

Computer Science: Faculty Publications

An unfolding of a polyhedron is produced by cutting the surface and flattening to a single, connected, planar piece without overlap (except possibly at boundary points). It is a long unsolved problem to determine whether every polyhedron may be unfolded. Here we prove, via an algorithm, that every orthogonal polyhedron (one whose faces meet at right angles) of genus zero may be unfolded. Our cuts are not necessarily along edges of the polyhedron, but they are always parallel to polyhedron edges. For a polyhedron of n vertices, portions of the unfolding will be rectangular strips which, in the worst case, …


Tumbleweed Exploratory Drilling Environmental Assessment, United States Deparment Of The Interior, Bureau Of Land Management Jun 2007

Tumbleweed Exploratory Drilling Environmental Assessment, United States Deparment Of The Interior, Bureau Of Land Management

All U.S. Government Documents (Utah Regional Depository)

This Environmental Assessment (EA) has been prepared to analyze Stewart Petroleum Corporation’s (Stewart) proposed exploratory natural gas drilling on their Federal leases within the Tumbleweed Oil and Gas Unit (Tumbleweed Unit). This EA is a site-specific analysis of potential impacts that could result with the implementation of Alternative - the Proposed Action; Alternative B – Buried Pipelines; or Alternative C - the No Action Alternative. The EA assists the Bureau of Land Management (BLM) in project planning and ensuring compliance with the National Environmental Policy Act (NEPA), and in making a determination as to whether any “significant” impacts could result …


A Multi-Scale Tikhonov Regularization Scheme For Implicit Surface Modeling, Jianke Zhu, Steven C. H. Hoi, Michael R. Lyu Jun 2007

A Multi-Scale Tikhonov Regularization Scheme For Implicit Surface Modeling, Jianke Zhu, Steven C. H. Hoi, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Kernel machines have recently been considered as a promising solution for implicit surface modelling. A key challenge of machine learning solutions is how to fit implicit shape models from large-scale sets of point cloud samples efficiently. In this paper, we propose a fast solution for approximating implicit surfaces based on a multi-scale Tikhonov regularization scheme. The optimization of our scheme is formulated into a sparse linear equation system, which can be efficiently solved by factorization methods. Different from traditional approaches, our scheme does not employ auxiliary off-surface points, which not only saves the computational cost but also avoids the problem …


Signatures Of Black Holes At The Lhc, Marco Cavaglia, Romulus Godang, Lucien M. Cremaldi, Donald J. Summers Jun 2007

Signatures Of Black Holes At The Lhc, Marco Cavaglia, Romulus Godang, Lucien M. Cremaldi, Donald J. Summers

Physics Faculty Research & Creative Works

Signatures of black hole events at CERN's Large Hadron Collider are discussed. Event simulations are carried out with the Fortran Monte Carlo generator CATFISH. Inelasticity effects, exact field emissivities, color and charge conservation, corrections to semiclassical black hole evaporation, gravitational energy loss at formation and possibility of a black hole remnant are included in the analysis.


Solutions Through Science: Economics Of Wildlife Damage Management Jun 2007

Solutions Through Science: Economics Of Wildlife Damage Management

United States Department of Agriculture Wildlife Services: Staff Publications

Wildlife is a public resource greatly valued by all Americans. As the stewards of this valuable resource, wildlife managers plan management actions based upon the best biological information available. Often, though, they do not clearly explain the economic benefits of their actions. Thorough economic analyses can aid in the prioritization of management efforts. Additionally, as more citizens request increasing fiscal responsibility from government agencies, wildlife managers can turn to economics to provide information on the financial benefits and costs associated with their management activities.
Within the National Wildlife Research Center (NWRC)—the research arm of the U.S. Department of Agriculture’s Wildlife …


A New Model For Cooperative Mobility In Support If Qos In Manets With Heterogeneous Autonomy Requirements, Ghassen Ben Brahim Jun 2007

A New Model For Cooperative Mobility In Support If Qos In Manets With Heterogeneous Autonomy Requirements, Ghassen Ben Brahim

Dissertations

Modern mobile ad-hoc networks (MANETs) frequently consist of nodes which exhibit a wide range of autonomy needs. This is particularly true in the settings where MANETs are model compelling, i.e. battlefield, response & rescue, and contexts requiring rapid deployment of mobile users. The time-critical nature of the underlying circumstances frequently requires deployment of both manned and unmanned nodes, and a coordination structure which provides prioritized tasking to them.

In classic ad-hoc networks settings, it is assumed that all nodes are autonomous and do not depend in any case on other nodes. In this research work, contrarily to this design, we …


Search For Techniparticles In ℯ + Jets Events At D0, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration Jun 2007

Search For Techniparticles In ℯ + Jets Events At D0, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration

Kenneth Bloom Publications

Fermilab Tevatron. Technicolor predicts that technipions π T decay dominantly into bb̅, bc̅, or b̅c, depending on their charge. In these events b and c quarks are identified by their secondary decay vertices within jets. Two analysis methods based on topological variables are presented. Since no excess above the standard model prediction was found, the result is presented as an exclusion in the πT vs ρ T mass plane for a given set of model parameters.


Measurement Of K0S, Λ And Λ Production At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, 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, L. Rinaldi Jun 2007

Measurement Of K0S, Λ And Λ Production At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, 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, L. Rinaldi

Faculty Publications

The production of the neutral strange hadrons K0S, Λ and Λ has been measured in ep collisions at HERA using the ZEUS detector. Cross sections, baryon-to-meson ratios, relative yields of strange and charged light hadrons, Λ (Λ) asymmetry and polarization have been measured in three kinematic regions: Q2 > 25 GeV2; 5 < Q2 < 25 GeV2; and in photoproduction (Q 2 0). In photoproduction the presence of two hadronic jets, each with at least 5 GeV transverse energy, was required. The measurements agree in general with Monte Carlo models and are consistent with measurements made at e+e- colliders, except for an enhancement of baryon relative to meson production in photoproduction. © Springer-Verlag / Società Italiana di Fisica 2007.


Eesi Newsletter, No. 1, June 2007, Energy & Environmental Security Initiative (University Of Colorado Boulder) Jun 2007

Eesi Newsletter, No. 1, June 2007, Energy & Environmental Security Initiative (University Of Colorado Boulder)

EESI: The Energy & Environmental Security Initiative [Newsletter] (2007)

No abstract provided.


Web Based Candidate Assessment System, Noel Kyne Jun 2007

Web Based Candidate Assessment System, Noel Kyne

Regis University Student Publications (comprehensive collection)

Devplex Technologies Limited is a privately owned company based in Galway Ireland. They have been operating for over two years and currently undertake contract projects for the travel and financial industries. The projects are varied and a wide range of skills are necessary. Devplex Technologies are currently undergoing expansion and intend to hire a number of new employees with varying levels of experience. Devplex Technologies also employ a high number of contractors, with varying skills and contract periods range from one month to twenty four months. The current technical leaders are all very busy with project work. The human resource …


Seismic Field Survey Of The Ground Of The National Research Institute Of Astronomy And Geophysics, Mohamed Said Hanno Jun 2007

Seismic Field Survey Of The Ground Of The National Research Institute Of Astronomy And Geophysics, Mohamed Said Hanno

Archived Theses and Dissertations

No abstract provided.


Linking Images And Sound In A 3d Museum Exhibit Demonstration, Briana M. Sullivan, Colin Ware, Matthew D. Plumlee Jun 2007

Linking Images And Sound In A 3d Museum Exhibit Demonstration, Briana M. Sullivan, Colin Ware, Matthew D. Plumlee

Center for Coastal and Ocean Mapping

No abstract provided.


A 20-Year Plan For Hunter/Angler Recruitment, Development And Retention In Nebraska Jun 2007

A 20-Year Plan For Hunter/Angler Recruitment, Development And Retention In Nebraska

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

Hunting and fishing are important parts of Nebraska’s rich heritage. These time-honored outdoor pursuits are important to overall lifestyle, well-being and natural resources of the citizens of Nebraska. The North American Model for Conservation was based primarily on the activism from our nation’s hunters and anglers. Their role helped develop and instill the seven basic premises of the model: Wildlife is to be held in public trust, there should be an elimination of market hunting, wildlife should be allocated by law, there should be hunting/angling opportunities for all citizens, wildlife should only be killed for legitimate reasons, wildlife should be …


The Evolution Of Protoplanetary Disks: A Decade Of Hst Coronagraphy, Sean Brittain, C Grady, G Schneider, B E. Woodgate, J P. Wisniewski, M L. Sitko, K Collins Jun 2007

The Evolution Of Protoplanetary Disks: A Decade Of Hst Coronagraphy, Sean Brittain, C Grady, G Schneider, B E. Woodgate, J P. Wisniewski, M L. Sitko, K Collins

Presentation

No abstract provided.


Pressure Utilization In Water Transmission Pipelines In Alain Region Considering Transient Conditions, Mohamed Sultan Al Maamari Jun 2007

Pressure Utilization In Water Transmission Pipelines In Alain Region Considering Transient Conditions, Mohamed Sultan Al Maamari

Theses

The residual pressure energy available in water transmission pipelines can be easily utilized via direct connection to the distribution system and bypassing the storage reservoirs and booster pumping stations. This thesis investigates the feasibility of bypassing a number of reservoirs and pumping stations in a small transmission system in AlAin City of United Arab Emirates. The system has a major transmission pumping station (AlAin Reception Pumping Station, or 'AARS') that hosts four fixed-speed pumps, a main 1200mm line, storage reservoirs and boosting pumps at three zones (Dahma, Markhania and Maqam), besides few other connection pipes. The system also has three …


Urban Spatial Pattern As Self-Organizing System: An Empirical Evaluation Of Firm Location Decisions In Cleveland–Akron Pmsa, Ohio, Mukesh Kumar, William M. Bowen, Miron Kaufman Jun 2007

Urban Spatial Pattern As Self-Organizing System: An Empirical Evaluation Of Firm Location Decisions In Cleveland–Akron Pmsa, Ohio, Mukesh Kumar, William M. Bowen, Miron Kaufman

Physics Faculty Publications

Economic models of urban spatial patterns have largely ignored complexity as an attribute of urban systems. Complexity theorists on the other hand have not made sufficiently serious and sustained attempts to verify empirically the relevance of complex systems models for urban spatial patterns. This research bridges this gap by simulating the evolution of an urban employment pattern as a self-organizing complex system and seeking its empirical validation. It estimates the model’s parameters by using firm data aggregated to the level of municipalities in Cleveland-Akron Consolidated Metropolitan Statistical Area in Ohio. The interaction among four parameters, forces of attraction and dispersion …


Parallel Fast Multipole Method For Molecular Dynamics, Reid G. Ormseth Jun 2007

Parallel Fast Multipole Method For Molecular Dynamics, Reid G. Ormseth

Theses and Dissertations

We report on a parallel version of the Fast Multipole Method (FMM) implemented in the classical molecular dynamics code, NAMD (Not Another Molecular Dynamics program). This novel implementation of FMM aims to minimize interprocessor communication through the modification of the FMM grid to match the hybrid force and spatial decomposition scheme already present in NAMD. This new implementation has the benefit of replacing all-to-all communications broadcasts with direct communications between nearest neighbors. This results in a significant reduction in the amount of communication compared to earlier attempts to integrate FMM into common molecular dynamics programs. The early performance of FMM …


Lp133-373 A New Chromospherically Active Eclipsing Dme Binary With A Distant, Cool White Dwarf Companion, T. R. Vaccaro, T. D. Oswalt, M. Rudkin, Adela Kawka, Stephane Vennes, Et Al. Jun 2007

Lp133-373 A New Chromospherically Active Eclipsing Dme Binary With A Distant, Cool White Dwarf Companion, T. R. Vaccaro, T. D. Oswalt, M. Rudkin, Adela Kawka, Stephane Vennes, Et Al.

Publications

We report the discovery of the partially eclipsing binary LP 133-373. Nearly identical eclipses along with observed photometric colors and spectroscopy indicate that it is a pair of chromospherically active dM4 stars in a circular 1.6 day orbit. Light and velocity curve modeling to our differential photometry and velocity data show that each star has a mass and radius of 0.340 ± 0.014 M☉ and 0.33 ± 0.02 R☉. The binary is itself part of a common proper motion pair with LP 133-374, a cool DC or possible DA white dwarf with a mass of 0.49-0.82 M☉, …


Characterization Of The Catalytically Active Mn(Ii)-Loaded Arge-Encoded N-Acetyl-L-Ornithine Deacetylase From Escherichia Coli, Wade C. Mcgregor, Sabina I. Swierczek, Brian Bennett, Richard C. Holz Jun 2007

Characterization Of The Catalytically Active Mn(Ii)-Loaded Arge-Encoded N-Acetyl-L-Ornithine Deacetylase From Escherichia Coli, Wade C. Mcgregor, Sabina I. Swierczek, Brian Bennett, Richard C. Holz

Physics Faculty Research and Publications

The catalytically competent Mn(II)-loaded form of the argE-encoded N-acetyl-l-ornithine deacetylase from Escherichia coli (ArgE) was characterized by kinetic, thermodynamic, and spectroscopic methods. Maximum N-acetyl-l-ornithine (NAO) hydrolytic activity was observed in the presence of one Mn(II) ion with k cat and K m values of 550 s−1 and 0.8 mM, respectively, providing a catalytic efficiency (k cat/K m) of 6.9 × 105 M−1 s−1. The ArgE dissociation constant (K d) for Mn(II) was determined to be 0.18 μM, correlating well with a value obtained by isothermal titration …


Micromagnetics Of The Domain Wall Mobility In Permalloy Nanowires, Andrew Kunz Jun 2007

Micromagnetics Of The Domain Wall Mobility In Permalloy Nanowires, Andrew Kunz

Physics Faculty Research and Publications

The domain wall mobility in long permalloy nanowires with thicknesses of 2-20 nm and widths of 50-200 nm has been simulated. The domain wall is driven into motion by an external magnetic field and the average wall mobility is calculated after the wall has traveled 2.5 mum along the wire. The results were obtained using the three-dimensional dynamic Landau-Lifshitz equation. We find that the domain wall mobility decreases linearly up to the critical field called the Walker field. The decreasing wall mobility is related to the decrease in the dynamic domain wall length as the applied field is increased. The …