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2015

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Articles 11551 - 11580 of 11604

Full-Text Articles in Physical Sciences and Mathematics

Investigating Anthropogenic Mammoth Extinction With Mathematical Models, Michael Frank, Anneliese Slaton, Teresa Tinta, Alex Capaldi Dec 2014

Investigating Anthropogenic Mammoth Extinction With Mathematical Models, Michael Frank, Anneliese Slaton, Teresa Tinta, Alex Capaldi

Alex Capaldi

One extinction hypothesis of the Columbian mammoth (Mammuthus columbi), called overkill, theorizes that early humans overhunted the animal. We employ two different approaches to test this hypothesis mathematically: analyze the stability of the equilibria of a 2D ordinary differential equations (ODE) system and develop a metapopulation differential equations model. The 2D ODE system is a modified predator-prey model that also includes migration. The metapopulation model is a spatial expansion of the first model on a rectangular grid. Using this metapopulation system, we model the migration of humans into North America and the response in the mammoth population. These approaches show …


Colloidal Plasmonic Titanium Nitride Nanoparticles: Properties And Applications, Urcan Guler, Sergey Suslov, Alexander V. Kildishev, Alexandra Boltasseva, Vladimir M. Shalaev Dec 2014

Colloidal Plasmonic Titanium Nitride Nanoparticles: Properties And Applications, Urcan Guler, Sergey Suslov, Alexander V. Kildishev, Alexandra Boltasseva, Vladimir M. Shalaev

U. Guler

Optical properties of colloidal plasmonic titanium nitride nanoparticles are examined with an eye on their photothermal and photocatalytic applications via transmission electron microscopy and optical transmittance measurements. Single crystal titanium nitride cubic nanoparticles with an average size of 50 nm, which was found to be the optimum size for cellular uptake with gold nanoparticles [1], exhibit plasmon resonance in the biological transparency window and demonstrate a high absorption efficiency. A self-passivating native oxide at the surface of the nanoparticles provides an additional degree of freedom for surface functionalization. The titanium oxide shell surrounding the plasmonic core can create new opportunities …


Analyzing Latency-Aware Self-Adaptation Using Stochastic Games And Simulations, Javier Camara, Gabriel A. Moreno, David Garlan, Bradley Schmerl Dec 2014

Analyzing Latency-Aware Self-Adaptation Using Stochastic Games And Simulations, Javier Camara, Gabriel A. Moreno, David Garlan, Bradley Schmerl

Gabriel A. Moreno

Self-adaptive systems must decide which adaptations to apply and when. In reactive approaches, adaptations are chosen and executed after some issue in the system has been detected (e.g., unforeseen attacks or failures). In proactive approaches, predictions are used to prepare the system for some future event (e.g., traffic spikes during holidays). In both cases, the choice of adaptation is based on the estimated impact it will have on the system. Current decision-making approaches assume that the impact will be instantaneous, whereas it is common that adaptations take time to produce their impact. Ignoring this latency is problematic because adaptations may …


Proactive Self-Adaptation Under Uncertainty: A Probabilistic Model Checking Approach, Gabriel A. Moreno, Javier Camara, David Garlan, Bradley Schmerl Dec 2014

Proactive Self-Adaptation Under Uncertainty: A Probabilistic Model Checking Approach, Gabriel A. Moreno, Javier Camara, David Garlan, Bradley Schmerl

Gabriel A. Moreno

Self-adaptive systems tend to be reactive and myopic, adapting in response to changes without anticipating what the subsequent adaptation needs will be. Adapting reactively can result in inefficiencies due to the system performing a suboptimal sequence of adaptations. Furthermore, when adaptations have latency, and take some time to produce their effect, they have to be started with sufficient lead time so that they complete by the time their effect is needed. Proactive latency-aware adaptation addresses these issues by making adaptation decisions with a look-ahead horizon and taking adaptation latency into account. In this paper we present an approach for proactive …


A Review Of Frequentist Tests For The 2x2 Binomial Trial, Chris Lloyd Dec 2014

A Review Of Frequentist Tests For The 2x2 Binomial Trial, Chris Lloyd

Chris J. Lloyd

The 2x2 binomial trial is the simplest of data structures yet its statistical analysis and the issues it raises have been debated and revisited for over 70 years. Which analysis should biomedical researchers use in applications? In this review, we consider frequentist tests only, specifically tests with control size either exactly or very close to exactly. These procedures can be classified as conditional and unconditional. Amongst tests motivated by a conditional model, Lancaster’s mid-p and Liebermeister’s test are less conservative than Fisher’s classical test, but do not control type 1 error. Within the conditional framework, only Fisher’s test can be …


Prognostic And Predictive Directions For Clinical Trials, Debashis Ghosh Dec 2014

Prognostic And Predictive Directions For Clinical Trials, Debashis Ghosh

Debashis Ghosh

In many clinical trials, treatment effects can be quite heterogeneous across subgroups so that individuals in different subgroups can receive different benefits of the treatment. This can be quite important for the purposes of clinical decision-making purposes. In this article, we introduce a general concept of risk score that is motivated by potential outcomes consider- ations. The concepts of prognostic and predictive directions for outcome data are defined. Their basis is in the dimension reduction (DR) literature and can also be motivated by con- ditional independence assumptions. Under some conditions, one can use existing methods from the DR literature to …


Application Of Fa´A Di Bruno’S Formula In The Construction Of Combinatorial Identities, Tian-Xiao He Dec 2014

Application Of Fa´A Di Bruno’S Formula In The Construction Of Combinatorial Identities, Tian-Xiao He

Tian-Xiao He

Chou, Hsu, and Shiue in [3] use Fa`a di Bruno’s formula give a class of composite series expansions. In this paper, we apply those expansions to construct a class of identities for Catalan numbers, large Schroder numbers, small Schroder numbers, parametric Catalan numbers, Stirling numbers, binomial numbers, some other recursive
number sequences, and recursive polynomial sequences.


Convexity Of Spherical Bernstein-B´Ezier Patches And Circular Bernstein-B´Ezier Curves, Tian-Xiao He, Ram Mohapatray Dec 2014

Convexity Of Spherical Bernstein-B´Ezier Patches And Circular Bernstein-B´Ezier Curves, Tian-Xiao He, Ram Mohapatray

Tian-Xiao He

This paper discusses the criteria of convexity of spherical Bernstein-Bezier patches, circular Bernstein-Bezier curves, and homogeneous Bernstein-Bezier polynomials.


Fabrication Of Ferroelectric Polymer Nanostructures On Flexible Substrates By Soft-Mold Reverse.Pdf, Shumin Li Dec 2014

Fabrication Of Ferroelectric Polymer Nanostructures On Flexible Substrates By Soft-Mold Reverse.Pdf, Shumin Li

Shumin Li

No abstract provided.


2015_Balzer_Adaptive.Pdf, Laura Balzer Dec 2014

2015_Balzer_Adaptive.Pdf, Laura Balzer

Laura B. Balzer

In randomized trials, pair-matching is an intuitive design strategy to protect study validity and to potentially
increase study power. In a common design, candidate units are identified, and their baseline characteristics used
to create the best n/2 matched pairs.Within the resulting pairs, the intervention is randomized, and the outcomes
measured at the end of follow-up.We consider this design to be adaptive, because the construction of thematched
pairs depends on the baseline covariates of all candidate units. As a consequence, the observed data cannot be
considered as n/2 independent, identically distributed pairs of units, as common practice assumes. Instead, the
observed …


Linkages Between Water Challenges And Land Use Planning In Megacities, Enjie Li, Joanna Endter-Wada, Shujuan Li Dec 2014

Linkages Between Water Challenges And Land Use Planning In Megacities, Enjie Li, Joanna Endter-Wada, Shujuan Li

Enjie Li

No abstract provided.


Architecture And Systems Ecology: Thermodynamic Principles Of Environmental Building Design, In Three Parts, William Braham Dec 2014

Architecture And Systems Ecology: Thermodynamic Principles Of Environmental Building Design, In Three Parts, William Braham

William W. Braham

Modern buildings are both wasteful machines that can be made more efficient and instruments of the massive, metropolitan system engendered by the power of high-quality fuels. A comprehensive method of environmental design must reconcile the techniques of efficient building design with the radical urban and economic reorganization that we face. Over the coming century, we will be challenged to return to the renewable resource base of the eighteenth-century city with the knowledge, technologies, and expectations of the twenty-first-century metropolis.

This book explores the architectural implications of systems ecology, which extends the principles of thermodynamics from the nineteenth-century focus on more …


Reasoning About Human Participation In Self-Adaptive Systems, Javier Camara, Gabriel A. Moreno, David Garlan Dec 2014

Reasoning About Human Participation In Self-Adaptive Systems, Javier Camara, Gabriel A. Moreno, David Garlan

Gabriel A. Moreno

Self-adaptive systems overcome many of the limitations of human supervision in complex software-intensive systems by endowing them with the ability to automatically adapt their structure and behavior in the presence of runtime changes. However, adaptation in some classes of systems (e.g., safety- critical) can benefit by receiving information from humans (e.g., acting as sophisticated sensors, decision-makers), or by involving them as system-level effectors to execute adaptations (e.g., when automation is not possible, or as a fallback mechanism). However, human participants are influenced by factors external to the system (e.g., training level, fatigue) that affect the likelihood of success when they …


Nitrates In Karst Systems: Comparing Impacted Systems To A Relatively Unimpacted System, Julie C. Angel, Eric Wade Peterson Dec 2014

Nitrates In Karst Systems: Comparing Impacted Systems To A Relatively Unimpacted System, Julie C. Angel, Eric Wade Peterson

Eric Wade Peterson

Karst aquifers are highly susceptible to contamination because of the connection with surface water. Nitrate contamination is common; with most karst aquifers exhibiting some degree of impact. This work assesses the potential impacts of anthropogenic activities on the Horn Hollow Valley (HHV) in Carter County Kentucky. HHV is a karst aquifer system that appears to be minimally impacted by nitrate and chloride contamination. Sampling of the HHV area was conducted from June 2005 to November 2006. Nitrate as nitrogen (NO3-N) concentrations were between 0.13 to 1.54 mg/L; chloride concentrations ranged from 1.43 to 66.3 mg/L. Impact from anthropogenic sources are …


Introducing Virtual Water Accounting To The Great Lakes, Stanley Mubako Dec 2014

Introducing Virtual Water Accounting To The Great Lakes, Stanley Mubako

Stanley Mubako

No abstract provided.


An Assessment Of South China Tiger Reintroduction Potential In Hupingshan And Houhe National Nature Reserves, China, Yiyuan Qin, Philip J. Nyhus, Courtney L. Larson, Charles J.W. Carroll, Jeff Muntifering, Thomas D. Dahmer, Lu Jun, Ronald L. Tilson Dec 2014

An Assessment Of South China Tiger Reintroduction Potential In Hupingshan And Houhe National Nature Reserves, China, Yiyuan Qin, Philip J. Nyhus, Courtney L. Larson, Charles J.W. Carroll, Jeff Muntifering, Thomas D. Dahmer, Lu Jun, Ronald L. Tilson

Philip J. Nyhus

Human-caused biodiversity loss is a global problem, large carnivores are particularly threatened, and the tiger (Panthera tigris) is among the world’s most endangered large carnivores. The South China tiger (Panthera tigris amoyensis) is the most critically endangered tiger subspecies and is considered functionally extinct in the wild. The government of China has expressed its intent to reintroduce a small population of South China tigers into a portion of their historic range as part of a larger goal to recover wild tiger populations in China. This would be the world’s first major tiger reintroduction program. A free-ranging population of 15–20 tigers …


Integrated Survival Analysis Using An Event Time Approach In A Bayesian Framework, Daniel Walsh, Victoria Dreitz, Dennis Heisey Dec 2014

Integrated Survival Analysis Using An Event Time Approach In A Bayesian Framework, Daniel Walsh, Victoria Dreitz, Dennis Heisey

Victoria Dreitz

No abstract provided.


Case Studies In Evaluating Time Series Prediction Models Using The Relative Mean Absolute Error, Nicholas G. Reich, Justin Lessler, Krzysztof Sakrejda, Stephen A. Lauer, Sopon Iamsirithaworn, Derek A T Cummings Dec 2014

Case Studies In Evaluating Time Series Prediction Models Using The Relative Mean Absolute Error, Nicholas G. Reich, Justin Lessler, Krzysztof Sakrejda, Stephen A. Lauer, Sopon Iamsirithaworn, Derek A T Cummings

Nicholas G Reich

Statistical prediction models inform decision-making processes in many real-world settings. Prior to using predictions in practice, one must rigorously test and validate candidate models to ensure that the proposed predictions have sufficient accuracy to be used in practice. In this paper, we present a framework for evaluating time series predictions that emphasizes computational simplicity and an intuitive interpretation using the relative mean absolute error metric. For a single time series, this metric enables comparisons of candidate model predictions against naive reference models, a method that can provide useful and standardized performance benchmarks. Additionally, in applications with multiple time series, this …


The Spatial Distribution Of Electric Field Intensity When The Motion Of Electric Charge In Absolute Space, Vildyan Yanbikov Dec 2014

The Spatial Distribution Of Electric Field Intensity When The Motion Of Electric Charge In Absolute Space, Vildyan Yanbikov

Vildyan Yanbikov

When driving an electric or gravitational charge in absolute space. Field created by these particles will have a different distribution in space. In comparison with by a stationary charge. When the charge motion of the deformation field.


Studying The Effects Of Non Oil Exports On Targeted Economic Growth In Iranian 5th Development Plan: A Computable General Equilibrium Approach, Rasoul Bakhsi Dastjerdi Dr., Reza Moosavi Mohseni Dr., Somayye Jafari Dec 2014

Studying The Effects Of Non Oil Exports On Targeted Economic Growth In Iranian 5th Development Plan: A Computable General Equilibrium Approach, Rasoul Bakhsi Dastjerdi Dr., Reza Moosavi Mohseni Dr., Somayye Jafari

Reza Moosavi Mohseni

we investigate the effects of non oil export on Iran’s economic growth using a computable general equilibrium (CGE) and study which tradable sectors has a larger share in reaching to targeted growth rate 8% in 5th socio economic development plan. We calibrate the model by GAMS (with emphasis on foreign trade sector). Numerical solution to the model is based on Iran’s social accounting matrix (SAM). Results show that 2.03% of targeted economic growth rate is achieved by encouraging a 6% growth in export. It also be mentioned that industry and mine sector in Iran, has more influence on growth than …


Copula Modelling Of Dependence In Multivariate Time Series, Michael S. Smith Dec 2014

Copula Modelling Of Dependence In Multivariate Time Series, Michael S. Smith

Michael Stanley Smith

Almost all existing nonlinear multivariate time series models remain linear, conditional on a point in time or latent regime. Here, an alternative is proposed, where nonlinear serial and cross-sectional dependence is captured by a copula model. The copula defines a multivariate time series on the unit cube. A drawable vine copula is employed, along with a factorization which allows the marginal and transitional densities of the time series to be expressed analytically. The factorization also provides for simple conditions under which the series is stationary and/or Markov, as well as being parsimonious. A parallel algorithm for computing the likelihood is …


Legal Issues: Security And Privacy With Mobile Devices, Brian Leonard, Maurice Dawson Dec 2014

Legal Issues: Security And Privacy With Mobile Devices, Brian Leonard, Maurice Dawson

Maurice Dawson

Privacy and security are two items being woven into the fabric of American law concerning mobile devices. This chapter will review and analyze the associated laws and policies that are currently in place or have been proposed to ensure proper execution of security measures for mobile and other devices while still protecting individual privacy. This chapter will address the fact that as the American society significantly uses mobile devices, it is imperative to understand the legal actions surrounding these technologies to include their associated uses. This chapter will also address the fact that with 9/11 in the not so distant …


Use Of Geographical Information Systems To Identify Counties In Georgia With High Risk For Childhood Lead Poisoning, R. Christopher Rustin, Christy Kuriatnyk, Byron Lobsinger, Simone Charles Dec 2014

Use Of Geographical Information Systems To Identify Counties In Georgia With High Risk For Childhood Lead Poisoning, R. Christopher Rustin, Christy Kuriatnyk, Byron Lobsinger, Simone Charles

R. Christopher Rustin

Background: For children in Georgia, lead poisoning is a substantial public health problem. Primary risk factors include low socioeconomic status and poor-quality housing built prior to 1978. The Environmental Health Team of the Georgia Department of Public Health (DPH) utilized geographical information system (GIS) technology and census housing data to identify counties in which children have high risk for lead poisoning. The purpose of this research was to update and refine previous maps developed with older technology and on a different geographic scale so that targeted public health interventions can be developed.

Methods: Data related to stratified and …


Riemann Hypothesis Disproved Using Infinity, Elements, Solution Operator Defined To Solve Riemann But Not Have Solutions 1/2 And Other Solutions With Real Solutions Not 1/2, James T. Struck Dec 2014

Riemann Hypothesis Disproved Using Infinity, Elements, Solution Operator Defined To Solve Riemann But Not Have Solutions 1/2 And Other Solutions With Real Solutions Not 1/2, James T. Struck

James T Struck

Riemann Hypothesis Disproved Using Infinity, Elements, solution operator defined to solve Riemann but not have solutions 1/2 and other Solutions with Real Solutions Not 1/2 The Riemann hypothesis is that all [[Triviality (mathematics)|nontrivial]] zeros of the analytical continuation of the [[Riemann zeta function]] have a real part of 1/2. A proof or disproof of this would have far-reaching implications in [[number theory]], especially for the distribution of [[prime number]]s. This was [[Hilbert's problems|Hilbert's eighth problem]], and is still considered an important open problem a century later. One of James T. Struck's Disproofs of the Riemann Hypothesis is that zeros can …


Zespół Energii Odnawialnej I Zrównoważonego Rozwoju (Eozr), Wojciech M. Budzianowski Dec 2014

Zespół Energii Odnawialnej I Zrównoważonego Rozwoju (Eozr), Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


Adaptive Pair-Matching In Randomized Trials With Unbiased And Efficient Effect Estimation, Laura Balzer, M Petersen, M Van Der Laan, The Search Consortium Dec 2014

Adaptive Pair-Matching In Randomized Trials With Unbiased And Efficient Effect Estimation, Laura Balzer, M Petersen, M Van Der Laan, The Search Consortium

Laura B. Balzer

In randomized trials, pair-matching is an intuitive design strategy to protect study validity and to potentially
increase study power. In a common design, candidate units are identified, and their baseline characteristics used
to create the best n∕2 matched pairs.Within the resulting pairs, the intervention is randomized, and the outcomes
measured at the end of follow-up.We consider this design to be adaptive, because the construction of thematched
pairs depends on the baseline covariates of all candidate units. As a consequence, the observed data cannot be
considered as n∕2 independent, identically distributed pairs of units, as common practice assumes. Instead, the
observed …


Experimental Check On The Validity Of The Special Theory Of Relativity, Vildyan Yanbikov Dec 2014

Experimental Check On The Validity Of The Special Theory Of Relativity, Vildyan Yanbikov

Vildyan Yanbikov

Calculation of quantitative characteristics of rotating interferometer Michelson-Morley experiment. The objective of the experiment. Confirmation alternate the Lorentz contraction of the interferometer arms as it rotates. Experimental check on the validity of the special theory of relativity.


Creating Computer Availability Maps, Scott Bacon Dec 2014

Creating Computer Availability Maps, Scott Bacon

Scott Bacon

During the fall semester of 2012, the Kimbel Library and Bryan Information Commons conducted a LibQUAL+ survey to gauge how patron needs were being met. Many survey respondents commented that there were not enough computers for use in the library buildings. This issue was remedied by the addition of over 70 percent more computer workstations in the new commons building, a move that was well received by patrons. However, these desktops still filled up quickly, especially during midterms and finals, so the library decided to create a dynamic system to show patrons which computers were available for use at any …


Simulating Univariate And Multivariate Nonnormal Distributions Through The Method Of Percentiles, Jennifer Koran, Todd C. Headrick, Tzu Chun Kuo Dec 2014

Simulating Univariate And Multivariate Nonnormal Distributions Through The Method Of Percentiles, Jennifer Koran, Todd C. Headrick, Tzu Chun Kuo

Todd Christopher Headrick

This article derives a standard normal-based power method polynomial transformation for Monte Carlo simulation studies, approximating distributions, and fitting distributions to data based on the method of percentiles. The proposed method is used primarily when (1) conventional (or L) moment-based estimators such as skew (or L-skew) and kurtosis (or L -kurtosis) are unknown or (2) data are unavailable but percentiles are known (e.g., standardized test score reports). The proposed transformation also has the advantage that solutions to polynomial coefficients are available in simple closed form and thus obviates numerical equation solving. A procedure is also described for simulating power method …


Spin-Exchange Optical Pumping At High Xenon Densities And Laser Fluxes: Principles And Practice, Boyd M. Goodson, Nicholas Whiting, Hayley Newton, Jason G. Skinner, Kaili Ranta, Panayiotis Nikolaou, Michael J. Barlow, Eduard Y. Chekmenev Dec 2014

Spin-Exchange Optical Pumping At High Xenon Densities And Laser Fluxes: Principles And Practice, Boyd M. Goodson, Nicholas Whiting, Hayley Newton, Jason G. Skinner, Kaili Ranta, Panayiotis Nikolaou, Michael J. Barlow, Eduard Y. Chekmenev

Nicholas Whiting

Once limited to the realm of fundamental physics experiments, hyperpolarized (HP) noble gases have been exploited for a wide range of applications across NMR and MRI. In most cases, hyperpolarized noble gases are prepared by spin-exchange optical pumping (SEOP)...