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2007

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Articles 1381 - 1410 of 6758

Full-Text Articles in Physical Sciences and Mathematics

Effective Communication Of Standard Errors And Confidence Intervals, Thomas A. Louis, Scott L. Zeger Aug 2007

Effective Communication Of Standard Errors And Confidence Intervals, Thomas A. Louis, Scott L. Zeger

Johns Hopkins University, Dept. of Biostatistics Working Papers

We recommend a format for communicating an estimate with its standard error or confidence interval. The format reinforces that the associated variability is an inseparable component of the estimate and it substantially improves clarity in tabular displays.


Parasite Findings In Archeological Remains: Diagnosis And Interpretation, Adauto Arajuo, Karl J. Reinhard, Luiz Fernando Ferreira Aug 2007

Parasite Findings In Archeological Remains: Diagnosis And Interpretation, Adauto Arajuo, Karl J. Reinhard, Luiz Fernando Ferreira

School of Natural Resources: Faculty Publications

Paleoparasitology has contributed to resolving the debate about the peopling of the Americas and determining the antiquity of human parasite infection. Hookworm (Ancylostomidae) and whipworm (Trichuris trichiura) and other exclusive human intestinal parasites have been recorded in pre-Columbian America. These parasite species originated in pre-hominids and have accompanied humans across continents when people went out of Africa. However, for those human populations that crossed the Bering Land Bridge from Siberia to Alaska, cold climate conditions hampered parasite transmission. Alternative migration routes have been proposed to explain the presence of these parasites in pre-Columbian populations in the Americas. Other …


Comparative Analysis Of Environmental Kuznets Curve In Central And Eastern Europe And South And East Asia, Yu-Chin Pang Aug 2007

Comparative Analysis Of Environmental Kuznets Curve In Central And Eastern Europe And South And East Asia, Yu-Chin Pang

Graduate Student Dissertations, Theses, Capstones, and Portfolios

Environmental deterioration has frequently been viewed as a problem that inevitably accompanies economic development and industrialization. However, different economic backgrounds might experience different kinds and levels of environmental deterioration. This study investigated environmental deterioration in two groups of countries with comparable income levels but different economic backgrounds-transitional Central and Eastern Europe (CEE) and non-transitional South and East Asian (SEA) countries.

This research utilized the environmental Kuznets curve (EKC) hypothesis to explain the relationships among macroeconomic indicators, country categories, and atmospheric concentrations in the CEE and SEA regions. Three research questions and six hypotheses and related sub-hypotheses were answered and tested …


Some Necessary Conditions Of Boolean Functions To Resist Algebraic Attacks., Deepak Dalai Dr. Aug 2007

Some Necessary Conditions Of Boolean Functions To Resist Algebraic Attacks., Deepak Dalai Dr.

Doctoral Theses

No abstract provided.


Construction Of (Hierarchical) Identity-Based Encryption Protocols Using Bilinear Pairing., Sanjit Chatterjee Dr. Aug 2007

Construction Of (Hierarchical) Identity-Based Encryption Protocols Using Bilinear Pairing., Sanjit Chatterjee Dr.

Doctoral Theses

Science, it is argued [65], advances through paradigm shifts. Concepts emerge that open-up new vistas of research, fundamentally changing the way we are used to looking at things. Between these paradigm shifts remain the periods of consolidation. Periods when human mind explores the newly found territory, shedding light on hitherto unknown dimensions. If radical changes are the hallmarks of paradigm shifts, the period within witnesses small but continuous developments, occasionally marked by its own milestones. It is in these periods that human faculty tries to grasp the full significance of the new concepts, consolidates its gains and thereby pushes the …


Surfactant Properties Of Atmospheric And Model Humic‐Like Substances (Hulis), Ilya Taraniuk, Ellen Graber, Alexander Kostinski, Yinon Rudich Aug 2007

Surfactant Properties Of Atmospheric And Model Humic‐Like Substances (Hulis), Ilya Taraniuk, Ellen Graber, Alexander Kostinski, Yinon Rudich

Department of Physics Publications

Surface‐active organics such as humic‐like substances (HULIS) are abundant in aerosol particles and can lower the surface tension of cloud droplets forming on secondary organic and biomass burning aerosols. How fast is the diffusion of these species, relative to the time scale of cloud droplet growth? Here we report surface tension measurements of solutions containing HULIS extracted from smoke and pollution aerosol particles as well those of molecular weight‐fractionated aquatic fulvic acids. Diffusion coefficients are estimated based on the Gibbs adsorption isotherms. The results suggest that HULIS diffusion to the surface of forming droplets is typically more rapid than the …


Game-Theoretic View On Intermediated Exchange, Thomas Grassl Aug 2007

Game-Theoretic View On Intermediated Exchange, Thomas Grassl

Dissertations, Master's Theses and Master's Reports - Open

Intermediaries permeate modern economic exchange. Most classical models on intermediated exchange are driven by information asymmetry and inventory management. These two factors are of reduced significance in modern economies. This makes it necessary to develop models that correspond more closely to modern financial marketplaces. The goal of this dissertation is to propose and examine such models in a game theoretical context.

The proposed models are driven by asymmetries in the goals of different market participants. Hedging pressure as one of the most critical aspects in the behavior of commercial entities plays a crucial role.

The first market model shows that …


Correcting Instrumental Variables Estimators For Systematic Measurement Error, Stijn Vansteelandt, Manoochehr Babanezhad, Els Goetghebeur Aug 2007

Correcting Instrumental Variables Estimators For Systematic Measurement Error, Stijn Vansteelandt, Manoochehr Babanezhad, Els Goetghebeur

Harvard University Biostatistics Working Paper Series

No abstract provided.


Significance Of Trends Toward Earlier Snowmelt Runoff, Columbia And Missouri Basin Headwaters, Western United States, Johnnie N. Moore, Joel T. Harper, Mark C. Greenwood Aug 2007

Significance Of Trends Toward Earlier Snowmelt Runoff, Columbia And Missouri Basin Headwaters, Western United States, Johnnie N. Moore, Joel T. Harper, Mark C. Greenwood

Geosciences Faculty Publications

We assess changes in runoff timing over the last 55 years at 21 gages unaffected by human influences, in the headwaters of the Columbia-Missouri Rivers. Linear regression models and tests for significance that control for ‘‘false discoveries’’ of many tests, combined with a conceptual runoff response model, were used to examine the detailed structure of spring runoff timing. We conclude that only about one third of the gages exhibit significant trends with time but over half of the gages tested show significant relationships with discharge. Therefore, runoff timing is more significantly correlated with annual discharge than with time. This result …


Development Of A New Ca Ii H And K Spectrophotometric Temperature Index, Kathleen Elizabeth Moncrieff Aug 2007

Development Of A New Ca Ii H And K Spectrophotometric Temperature Index, Kathleen Elizabeth Moncrieff

Theses and Dissertations

We are developing a new spectrophotometric temperature index based on the Ca II H and K lines. Because these lines are present even in very cool stars and because the Ca II H line is blended with the H-epsilon line in hot stars, this index should cover a very broad range of spectral types. Our data set consisted of 95 stars with spectral types ranging from O9 to M1. We examined five different indices based on the Ca II H + H-epsilon and K lines, as well as single-wavelength indices centered on each of the H-delta and H-gamma lines, which …


Diffusive Compression Acceleration Of Energetic Particles With An Application To Shock Acceleration Near Injection Energies, Ming Zhang Aug 2007

Diffusive Compression Acceleration Of Energetic Particles With An Application To Shock Acceleration Near Injection Energies, Ming Zhang

Aerospace, Physics, and Space Science Faculty Publications

The behavior of energetic charged particles accelerated by a continuous plasma compression profile is explored in the framework of diffusion. At high enough energies, the accelerated particles have a power-law spectrum with a slope generally steeper than a shock spectrum with the same compression ratio. The spectral slope depends on the ratio of the diffusion coefficient to the product of the upstream plasma speed and the thickness of the compression region. In the limit of large diffusion, the spectrum becomes identical to that of diffusive shock acceleration, and when diffusion is small enough, it is consistent with adiabatic acceleration by …


Risk Assessment In Early Software Design Based On The Software Function-Failure Design Method, Jayson P. Vucovich, Robert B. Stone, Xiaoqing Frank Liu, Irem Y. Tumer Aug 2007

Risk Assessment In Early Software Design Based On The Software Function-Failure Design Method, Jayson P. Vucovich, Robert B. Stone, Xiaoqing Frank Liu, Irem Y. Tumer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Potential software failures present a sizable risk element in the design and development of many systems. In this paper, we augment the Software Function-Failure Design method, which is capable of predicting potential software failures in the very early stages of design, with the Risk in Early Design technique. This synergistic combination allows a risk assessment to be conducted at an early time in the software development process when traditional techniques are not applicable. The results are concise risk statements regarding the potential failure of functionalities with likelihood and consequence quantifications that can be used as part of a risk management …


The 14N Quadrupole Coupling In Hexamethylene Triperoxide Diamine (Hmtd), John Persons, Gerard S. Harbison Aug 2007

The 14N Quadrupole Coupling In Hexamethylene Triperoxide Diamine (Hmtd), John Persons, Gerard S. Harbison

Gerard Harbison Publications

Using high-field NMR, we have determined the magnitude of the nuclear quadrupole interaction in hexamethylene triperoxide diamine (HMTD), the explosive allegedly used in the London bombings of July 2005. The experimental quadrupolar coupling constant, 5.334 MHz, is in good agreement with quantum chemical calculations. The predicted single zero-field transition frequency should lie in a relatively empty part of the 14N nuclear quadrupole resonance (NQR) spectrum; the spin relaxation rate is reasonably fast.


Torsional Waveguide Density Sensor, Radek Glaser Aug 2007

Torsional Waveguide Density Sensor, Radek Glaser

Radek Glaser

As a part of National Science Foundation-Research for Undergraduates program, a torsional wave guide density sensor has been investigated in the Laboratory of Surface Science and Technology at the University Of Maine. This simple design uses torsional piezo-electric transducers to generate torsional mode in a long circular rod.
The non-circular portion of the wave guide allows for the measurement of different properties of fluids. Theory is presented from energy balance perspective and from the acoustic wave propagation approach. A series of experiments have been conducted with variety of liquids and gases. Several relationships have been verified and also new have …


Investigation Of Proton-Proton Short-Range Correlations Via The (12)C(E,E′Pp) Reaction, R. Shneor, Timothy Holmstrom, Jefferson Hall Lab A Collaboration Aug 2007

Investigation Of Proton-Proton Short-Range Correlations Via The (12)C(E,E′Pp) Reaction, R. Shneor, Timothy Holmstrom, Jefferson Hall Lab A Collaboration

Chemistry & Physics Faculty Publications

We investigated simultaneously the 12C(e,ep) and 12C(e,epp) reactions at Q2=2  (GeV/c)2, xB=1.2, and in an (e, ep) missing-momentum range from 300 to 600  MeV/c. At these kinematics, with a missing momentum greater than the Fermi momentum of nucleons in a nucleus and far from the delta excitation, short-range nucleon-nucleon correlations are predicted to dominate the reaction. For (9.5±2)% of the 12C(e,ep) events, a recoiling partner proton was observed back-to-back to the 12C(e,ep) missing-momentum vector, an experimental signature of correlations.


A Supply Chain Design Model With Unreliable Supply, Lian Qi, Zuo-Jun Max Shen Aug 2007

A Supply Chain Design Model With Unreliable Supply, Lian Qi, Zuo-Jun Max Shen

Business and Information Technology Faculty Research & Creative Works

Uncertainties abound within a supply chain and have big impacts on its performance. We propose an integrated model for a three-tiered supply chain network with one supplier, one or more facilities and retailers. This model takes into consideration the unreliable aspects of a supply chain. the properties of the optimal solution to the model are analyzed to reveal the impacts of supply uncertainty on supply chain design decisions. We also propose a general solution algorithm for this model. Computational experience is presented and discussed.


Coherent Excitation Of The Optic Phonon In Si: Transiently Stimulated Raman Scattering With Afinite-Lifetime Electronic Excitation, D. Mark Riffe, A. J. Sabbah Aug 2007

Coherent Excitation Of The Optic Phonon In Si: Transiently Stimulated Raman Scattering With Afinite-Lifetime Electronic Excitation, D. Mark Riffe, A. J. Sabbah

All Physics Faculty Publications

Using 28-fs, 800-nm laser pulses we have coherently excited and subsequently probed, with time-dependent reflectivity, the Si zone-center optic phonon. The phonon-induced reflectivity change ΔR∕R is well described by the response of an underdamped oscillator: ΔR∕R∝ exp(−t∕τph) cos(2πt∕Tph+ϕ). The measured phase ϕ indicates that transiently stimulated Raman scattering (TSRS) is responsible for the coherent-phonon generation: our results are in good agreement with a recent theory of TSRS for opaque materials [ T. E. Stevens et al. Phys. Rev. B 65 144304 (2002)] when we extend the theory to include the finite lifetime of the excited charge …


The Ecology Of Vertebrate Pests And Integrated Pest Management (Ipm), Gary W. Witmer Aug 2007

The Ecology Of Vertebrate Pests And Integrated Pest Management (Ipm), Gary W. Witmer

United States Department of Agriculture Wildlife Services: Staff Publications

Across the world, vertebrates cause considerable annual damage to agriculture, property, human health and safety, and natural resources. Although some species of all vertebrate groups have been implicated in damage, the species most often involved in serious amounts of damage are birds and mammals. Agroecosystems have provided many new opportunities for vertebrates to exploit, resulting in their becoming serious "pests" with humans taking various steps to protect their agricultural resources. This conflict has intensified as the human population has increased, efforts to get more production out of traditional croplands have intensified, and marginal lands have been placed into crop production. …


Design Of A Web-Based Project Tracking System, Robert F. Tschiemer Aug 2007

Design Of A Web-Based Project Tracking System, Robert F. Tschiemer

Regis University Student Publications (comprehensive collection)

This paper explores the design of a prototype Web-based database application that will support a professional project tracking system for students and Advisers. Specifically, this paper combines a relational database and web-based applications that are integrated into NET framework and PHP code technologies. The initial database-driven web application is designed for 200-300 student usage and is scalable to a 1500 student project usage. The methodology that governs the application design was determined by review of waterfall methodology approach. The chosen development methodology provides the application design and prototype construction. The actual database design and web page implementation will conclude the …


Observation Of Type-I And Type-Ii Excitons In Strained Si/Sige Quantum-Well Structures, K. Y. Wang, W. P. Huang, H. H. Cheng, Greg Sun, R. A. Soref, R. J. Nicholas, Y. W. Suen Aug 2007

Observation Of Type-I And Type-Ii Excitons In Strained Si/Sige Quantum-Well Structures, K. Y. Wang, W. P. Huang, H. H. Cheng, Greg Sun, R. A. Soref, R. J. Nicholas, Y. W. Suen

Physics Faculty Publications

The authors report photoluminescence (PL) measurement on a series of Si/SiGequantum-well structures that had different internal strain distributions. When each sample was placed in a high magnetic field, the field-dependent energy shift of the relevant PL peaks revealed either type-I or type-II exciton formation depending on the strain distribution. This observation is in agreement with theoretical modeling. The present investigation shows that type-I band alignment—desired for electroluminescent devices—can be achieved by strain engineering.


Ontology Aware Software Service Agents: Meeting Ordinary User Needs On The Semantic Web, Muhammed Jassem Al Muhammed Aug 2007

Ontology Aware Software Service Agents: Meeting Ordinary User Needs On The Semantic Web, Muhammed Jassem Al Muhammed

Theses and Dissertations

To achieve the dream of the semantic web, it must be possible for ordinary users to invoke services. It is clear that users need simple-to-invoke-and-use services. This dissertation offers an ontological approach to declaratively create services that users can invoke using free-form, natural-language-like specifications. Our approach uses task ontologies as foundational knowledge. A task ontology consists of a domain ontology and a process ontology. The domain ontology encodes domain information such as possible constraints and instances in terms of object sets, relationship sets among these object sets, and operations over values in object sets and relationship sets. The process ontology …


Roundtable Discussion: Southern Nevada’S Future In Renewable And Sustainable Energy, Oliver Hemmers Aug 2007

Roundtable Discussion: Southern Nevada’S Future In Renewable And Sustainable Energy, Oliver Hemmers

UNLV Renewable Energy Symposium

This inaugural event is dedicated to showcasing the renewable/sustainable energy projects of UNLV faculty, staff, students, and collaborators, as well as other external projects underway statewide and nationally. The development and utilization of new technologies to protect the environment, achieve energy independence, and strengthen the economy will be explored. Speakers and poster-session presenters will provide further insight to many ongoing projects and innovative research ideas.

Organized by UNLV’s Office of Strategic Energy Programs, the event offers participants the opportunity to learn about energy projects and will encourage networking and collaboration. This symposium is intended for researchers, educators, students, policy makers, …


Fundamental Studies Of Hydrogen Storage And Catalysis, Balakrishnan Naduvalath Aug 2007

Fundamental Studies Of Hydrogen Storage And Catalysis, Balakrishnan Naduvalath

UNLV Renewable Energy Symposium

This inaugural event is dedicated to showcasing the renewable/sustainable energy projects of UNLV faculty, staff, students, and collaborators, as well as other external projects underway statewide and nationally. The development and utilization of new technologies to protect the environment, achieve energy independence, and strengthen the economy will be explored. Speakers and poster-session presenters will provide further insight to many ongoing projects and innovative research ideas.

Organized by UNLV’s Office of Strategic Energy Programs, the event offers participants the opportunity to learn about energy projects and will encourage networking and collaboration. This symposium is intended for researchers, educators, students, policy makers, …


Understanding And Optimizing Surfaces And Interfaces In Energy Conversion Devices, Clemens Heske Aug 2007

Understanding And Optimizing Surfaces And Interfaces In Energy Conversion Devices, Clemens Heske

UNLV Renewable Energy Symposium

This inaugural event is dedicated to showcasing the renewable/sustainable energy projects of UNLV faculty, staff, students, and collaborators, as well as other external projects underway statewide and nationally. The development and utilization of new technologies to protect the environment, achieve energy independence, and strengthen the economy will be explored. Speakers and poster-session presenters will provide further insight to many ongoing projects and innovative research ideas.

Organized by UNLV’s Office of Strategic Energy Programs, the event offers participants the opportunity to learn about energy projects and will encourage networking and collaboration. This symposium is intended for researchers, educators, students, policy makers, …


Hydrogen In Transportation Applications, Amber Broch Aug 2007

Hydrogen In Transportation Applications, Amber Broch

UNLV Renewable Energy Symposium

This inaugural event is dedicated to showcasing the renewable/sustainable energy projects of UNLV faculty, staff, students, and collaborators, as well as other external projects underway statewide and nationally. The development and utilization of new technologies to protect the environment, achieve energy independence, and strengthen the economy will be explored. Speakers and poster-session presenters will provide further insight to many ongoing projects and innovative research ideas.

Organized by UNLV’s Office of Strategic Energy Programs, the event offers participants the opportunity to learn about energy projects and will encourage networking and collaboration. This symposium is intended for researchers, educators, students, policy makers, …


Hydrogen Power System For Remote Applications, Curtis Robbins Aug 2007

Hydrogen Power System For Remote Applications, Curtis Robbins

UNLV Renewable Energy Symposium

This inaugural event is dedicated to showcasing the renewable/sustainable energy projects of UNLV faculty, staff, students, and collaborators, as well as other external projects underway statewide and nationally. The development and utilization of new technologies to protect the environment, achieve energy independence, and strengthen the economy will be explored. Speakers and poster-session presenters will provide further insight to many ongoing projects and innovative research ideas.

Organized by UNLV’s Office of Strategic Energy Programs, the event offers participants the opportunity to learn about energy projects and will encourage networking and collaboration. This symposium is intended for researchers, educators, students, policy makers, …


Assessment Of Wind Energy For Nevada Using Towers And Mesoscale Modeling, Darko Koracin Aug 2007

Assessment Of Wind Energy For Nevada Using Towers And Mesoscale Modeling, Darko Koracin

UNLV Renewable Energy Symposium

This inaugural event is dedicated to showcasing the renewable/sustainable energy projects of UNLV faculty, staff, students, and collaborators, as well as other external projects underway statewide and nationally. The development and utilization of new technologies to protect the environment, achieve energy independence, and strengthen the economy will be explored. Speakers and poster-session presenters will provide further insight to many ongoing projects and innovative research ideas. Organized by UNLV’s Office of Strategic Energy Programs, the event offers participants the opportunity to learn about energy projects and will encourage networking and collaboration. This symposium is intended for researchers, educators, students, policy makers, …


Assessing Wind Energy Potential For Nevada, Darrell Pepper Aug 2007

Assessing Wind Energy Potential For Nevada, Darrell Pepper

UNLV Renewable Energy Symposium

This inaugural event is dedicated to showcasing the renewable/sustainable energy projects of UNLV faculty, staff, students, and collaborators, as well as other external projects underway statewide and nationally. The development and utilization of new technologies to protect the environment, achieve energy independence, and strengthen the economy will be explored. Speakers and poster-session presenters will provide further insight to many ongoing projects and innovative research ideas.

Organized by UNLV’s Office of Strategic Energy Programs, the event offers participants the opportunity to learn about energy projects and will encourage networking and collaboration. This symposium is intended for researchers, educators, students, policy makers, …


Photonics In Engineering, Rama Venkat Aug 2007

Photonics In Engineering, Rama Venkat

UNLV Renewable Energy Symposium

This inaugural event is dedicated to showcasing the renewable/sustainable energy projects of UNLV faculty, staff, students, and collaborators, as well as other external projects underway statewide and nationally. The development and utilization of new technologies to protect the environment, achieve energy independence, and strengthen the economy will be explored. Speakers and poster-session presenters will provide further insight to many ongoing projects and innovative research ideas.

Organized by UNLV’s Office of Strategic Energy Programs, the event offers participants the opportunity to learn about energy projects and will encourage networking and collaboration. This symposium is intended for researchers, educators, students, policy makers, …


Reduction In Northward Incursions Of The South Asian Monsoon Since ~1400 Ad Inferred From A Mt. Everest Ice Core, Susan D. Kaspari, Paul Andrew Mayewski, Shichang Kang, Sharon B. Sneed, Shugui Hou, Roger Hooke, Karl J. Kreutz, D. Introne, M. Handley, Kirk A. Maasch, Dahe Qin, J. Ren Aug 2007

Reduction In Northward Incursions Of The South Asian Monsoon Since ~1400 Ad Inferred From A Mt. Everest Ice Core, Susan D. Kaspari, Paul Andrew Mayewski, Shichang Kang, Sharon B. Sneed, Shugui Hou, Roger Hooke, Karl J. Kreutz, D. Introne, M. Handley, Kirk A. Maasch, Dahe Qin, J. Ren

Earth Science Faculty Scholarship

A highly resolved Mt. Everest ice core reveals a decrease in marine and increase in continental air masses related to relatively high summer surface pressure over Mongolia, and reduction in northward incursions of the summer South Asian monsoon since similar to 1400 AD. Previously published proxy records from lower sites south of the Himalayas indicate strengthening of the monsoon since this time. These regional differences are consistent with a south north seesaw in convective activity in the Asian monsoon region, and reflect a southward shift in the mean summer position of the monsoon trough since similar to 1400 AD. The …