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2009

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Articles 7561 - 7590 of 7616

Full-Text Articles in Physical Sciences and Mathematics

Living Anionic Polymerization Using A Microfluidic Reactor, Kazunori Iida, Thomas Q. Chastek, Kathryn L. Beers, Kevin Cavicchi, Jaehun Chun, Fasolka J. Michael Dec 2008

Living Anionic Polymerization Using A Microfluidic Reactor, Kazunori Iida, Thomas Q. Chastek, Kathryn L. Beers, Kevin Cavicchi, Jaehun Chun, Fasolka J. Michael

Kevin Cavicchi

Living anionic polymerizations were conducted within aluminum-polyimide microfluidic devices. Polymerizations of styrene in cyclohexane were carried out at various conditions, including elevated temperature (60 degrees C) and high monomer concentration (42%, by volume). The reactions were safely maintained at a controlled temperature at all points in the reactor. Conducting these reactions in a batch reactor results in uncontrolled heat generation with potentially dangerous rises in pressure. Moreover, the microfluidic nature of these devices allows for flexible 2D designing of the flow channel. Four flow designs were examined (straight, periodically pinched, obtuse zigzag, and acute zigzag channels). The ability to use …


Detection Of Gene Pathways With Predictive Power For Breast Cancer Prognosis, Shuangge Ma Dec 2008

Detection Of Gene Pathways With Predictive Power For Breast Cancer Prognosis, Shuangge Ma

Shuangge Ma

Prognosis of breast cancer is of great scientific and practical interest. Biomedical studies suggest that clinical and environmental risk factors do not have satisfactory predictive power for prognosis. Multiple gene profiling studies have been conducted, searching for predictive genomic measurements. Genes have the inherent pathway structure, where pathways are composed of multiple genes with similar biological functions. The goal of this study is to identify gene pathways with predictive power for breast cancer prognosis. Although multiple pathway analysis methods are available, they have certain drawbacks and are not suitable for the proposed analysis. In this article, we develop a new …


Alamethicin In Lipid Bilayers: Combined Use Of X-Ray Scattering And Md Simulations, Jianjun Pan, D. Peter Tieleman, John F. Nagle, Norbert Kučerka, Prof. Stephanie Tristram-Nagle Ph.D. Dec 2008

Alamethicin In Lipid Bilayers: Combined Use Of X-Ray Scattering And Md Simulations, Jianjun Pan, D. Peter Tieleman, John F. Nagle, Norbert Kučerka, Prof. Stephanie Tristram-Nagle Ph.D.

Prof. Stephanie Tristram-Nagle Ph.D.

We study fully hydrated bilayers of two di-monounsaturated phospholipids diC18:1PC (DOPC) and diC22:1PC with varying amounts of alamethicin (Alm). We combine the use of X-ray diffuse scattering and molecular dynamics simulations to determine the orientation of alamethicin in model lipids. Comparison of the experimental and simulated form factors shows that Alm helices are inserted transmembrane at high humidity and high concentrations, in agreement with earlier results. The X-ray scattering data and the MD simulations agree that membrane thickness changes very little up to 1/10 Alm/ DOPC. In contrast, the X-ray data indicate that the thicker diC22:1PC membrane thins with added …


The Role Of The Theory-Of-Mind Cortical Network In The Comprehension Of Narratives, Robert Mason, Marcel Just Dec 2008

The Role Of The Theory-Of-Mind Cortical Network In The Comprehension Of Narratives, Robert Mason, Marcel Just

Marcel Adam Just

No abstract provided.


Rethinking Lda: Why Priors Matter, Hanna M. Wallach, David Minmo, Andrew Mccallum Dec 2008

Rethinking Lda: Why Priors Matter, Hanna M. Wallach, David Minmo, Andrew Mccallum

Hanna M. Wallach

Implementations of topic models typically use symmetric Dirichlet priors with fixed concentration parameters, with the implicit assumption that such "smoothing parameters" have little practical effect. In this paper, we explore several classes of structured priors for topic models. We find that an asymmetric Dirichlet prior over the document-topic distributions has substantial advantages over a symmetric prior, while an asymmetric prior over the topic-word distributions provides no real benefit. Approximation of this prior structure through simple, efficient hyperparameter optimization steps is sufficient to achieve these performance gains. The prior structure we advocate substantially increases the robustness of topic models to variations …


Social Interaction With Robots And Agents: Where Do We Stand, Where Do We Go?, Eva Hudlicka, Sabine Payr, Rodrigo Ventura, Christian Becker-Asano, Kerstin Fischer, Iolanda Leite, Ana Paiva, Christian Von Scheve Dec 2008

Social Interaction With Robots And Agents: Where Do We Stand, Where Do We Go?, Eva Hudlicka, Sabine Payr, Rodrigo Ventura, Christian Becker-Asano, Kerstin Fischer, Iolanda Leite, Ana Paiva, Christian Von Scheve

Eva Hudlicka

Robots and agents are becoming increasingly prominent in everyday life, taking on a variety of roles, including helpers, coaches, and even social companions. A core requirement for these social agents is the ability to establish and maintain long-term trusting and engaging relationship with their human users. Much research has already been done on the prerequisites for these types of social agents and robots, in affective computing, social computing and affective HCI. A number of disciplines within psychology and the social sciences are also relevant, contributing theories, data and methods relevant for the emerging areas of social robotics, and social computing …


Statistical-Based Wcet Estimation And Validation, Jeffery Hansen, Scott A. Hissam, Gabriel A. Moreno Dec 2008

Statistical-Based Wcet Estimation And Validation, Jeffery Hansen, Scott A. Hissam, Gabriel A. Moreno

Gabriel A. Moreno

In this paper we present a measurement-based approach that produces both a WCET (Worst Case Execution Time) estimate, and a prediction of the probability that a future execution time will exceed our estimate. Our statistical-based approach uses extreme value theory to build a model of the tail behavior of the measured execution time value. We validate our approach using an industrial data set comprised of over 150 sampled components and nearly 200 million sample execution times. Each trace is divided into two segments, with one used to make the WCET estimate, and the second used check our prediction of the …


Bounding The Probability Of Error For High Precision Recognition, Andrew Kae, Gary B. Huang, Erik G. Learned-Miller Dec 2008

Bounding The Probability Of Error For High Precision Recognition, Andrew Kae, Gary B. Huang, Erik G. Learned-Miller

Erik G Learned-Miller

We consider models for which it is important, early in proces sing, to estimate some variables with high precision, but perhaps at relative ly low rates of recall. If some variables can be identified with near certainty, then th ey can be conditioned upon, allowing further inference to be done efficiently. Spe cifically, we consider optical character recognition (OCR) systems that can be boo tstrapped by identify- ing a subset of correctly translated document words with ver y high precision. This “clean set” is subsequently used as document-specific train ing data. While many current OCR systems produce measures of confidence …


Towards The Integration Of Social Media With Traditional Information Systems, Michael J. Rees, Peta J. Hopkins Dec 2008

Towards The Integration Of Social Media With Traditional Information Systems, Michael J. Rees, Peta J. Hopkins

Michael J Rees

This paper was inspired by the authors’ personal experience of using social media systems over the last two years. During that time both authors have used a range of public, private and hosted social media systems for their professional activities and well as for personal use. They and other colleagues are convinced that a unified approach to social media systems can benefit the communications processes within our institution and our interaction with our important existing and potential clients, the students and alumni.


Properties Of Multilevel Block $\Alpha$-Circulants, William F. Trench Dec 2008

Properties Of Multilevel Block $\Alpha$-Circulants, William F. Trench

William F. Trench

No abstract provided.


Bounding The Probability Of Error For High Precision Recognition, Andrew Kae, Gary B. Huang, Erik G. Learned-Miller Dec 2008

Bounding The Probability Of Error For High Precision Recognition, Andrew Kae, Gary B. Huang, Erik G. Learned-Miller

Andrew Kae

We consider models for which it is important, early in proces sing, to estimate some variables with high precision, but perhaps at relative ly low rates of recall. If some variables can be identified with near certainty, then th ey can be conditioned upon, allowing further inference to be done efficiently. Spe cifically, we consider optical character recognition (OCR) systems that can be boo tstrapped by identify- ing a subset of correctly translated document words with ver y high precision. This “clean set” is subsequently used as document-specific train ing data. While many current OCR systems produce measures of confidence …


Non-Parametric Curve Alignment, Marwan Mattar, Michael G. Ross, Erik G. Learned-Miller Dec 2008

Non-Parametric Curve Alignment, Marwan Mattar, Michael G. Ross, Erik G. Learned-Miller

Erik G Learned-Miller

Congealing is a flexible nonparametric data-driven framework for the joint alignment of data. It has been successfully applied to the joint alignment of binary images of digits, binary images of object silhouettes, grayscale MRI images, color images of cars and faces, and 3D brain volumes. This research enhances congealing to practically and effectively apply it to curve data. We develop a parameterized set of nonlinear transformations that allow us to apply congealing to this type of data. We present positive results on aligning synthetic and real curve data sets and conclude with a discussion on extending this work to simultaneous …


Environmentally Friendly Organic Synthesis Using Bismuth Compounds. Bismuth(Iii) Bromide Catalyzed Synthesis Of Substituted Tetrahydroquinoline Derivatives, Ram S. Mohan, Jamie L. Rogers, Justin J. Ernat, Herbie Yung Dec 2008

Environmentally Friendly Organic Synthesis Using Bismuth Compounds. Bismuth(Iii) Bromide Catalyzed Synthesis Of Substituted Tetrahydroquinoline Derivatives, Ram S. Mohan, Jamie L. Rogers, Justin J. Ernat, Herbie Yung

Ram S. Mohan

The bismuth bromide catalyzed synthesis of a range of substituted tetrahydroquinoline derivatives via a three component coupling reaction between substituted anilines and enol ethers is reported. Bismuth compounds are attractive for use as catalysts because of their remarkably low toxicity. Bismuth bromide is relatively inexpensive and easy to handle, and hence preferable to other corrosive catalysts previously used for synthesis of tetrahydroquinoline derivatives.


Evaluation Of Heterogeneity In Pharmacotherapy Trials For Drug Dependence: A Bayesian Approach, Charles E. Green, F. G. Moeller, J. M. Schmitz, Joseph F. Lucke, S. D. Lane, A. C. Swann, Robert E. Lasky, Joseph P. Carbonari Dec 2008

Evaluation Of Heterogeneity In Pharmacotherapy Trials For Drug Dependence: A Bayesian Approach, Charles E. Green, F. G. Moeller, J. M. Schmitz, Joseph F. Lucke, S. D. Lane, A. C. Swann, Robert E. Lasky, Joseph P. Carbonari

Joseph Lucke

Difficulty identifying effective pharmacotherapies for cocaine dependence has led to suggestions that subgroup differences may account for some of the heterogeneity in treatment response. Well-attested methodologicalifficulties associated with these analyses recommend the use of Bayesian statistical reasoning for evaluation of salient interaction effects.

Methods: A secondary data analysis of a previously published, double-blind, randomized controlled trial examines the interaction of decision-making, as measured by the Iowa Gambling Task, and citalopram in increasing longest sustained abstinence from cocaine use.

Results: Bayesian analysis indicated that there was a 99% chance that improved decision-making enhances response to citalopram. Given the strong positive nature …


Fundamentals For Using Geographic Information Science To Measure The Effectiveness Of Land Conservation Projects, Robert G. Pontius Jr., Shaily Menon, Joseph Duncan, Shalini Gupta Dec 2008

Fundamentals For Using Geographic Information Science To Measure The Effectiveness Of Land Conservation Projects, Robert G. Pontius Jr., Shaily Menon, Joseph Duncan, Shalini Gupta

Shaily Menon

Some humans spend a tremendous amount of effort to change landscapes from a “natural” state to a “developed” state for a variety of desirable economic uses, such as urban, agriculture, transportation, and mining. Others spend a tremendous amount of effort to prevent such development in order to conserve the landscapes for a variety of important environmental uses, such as biodiversity maintenance, carbon storage, water filtration, and landslide prevention. It would be efficient in theory if a society were to focus its development efforts at locations that give the largest economic utility per area developed, and to focus its conservation efforts …


Suchy System Oczyszczania Spalin Ze Spalania Odpadów Niebezpiecznych – Ocena Skuteczności Usuwania Substancji Gazowych I Możliwości Spełniania Standardów Emisyjnych, Robert Oleniacz Dec 2008

Suchy System Oczyszczania Spalin Ze Spalania Odpadów Niebezpiecznych – Ocena Skuteczności Usuwania Substancji Gazowych I Możliwości Spełniania Standardów Emisyjnych, Robert Oleniacz

Robert Oleniacz

The research object was a medical waste incineration plant with a flue-gas treatment system based on dry sorption agent injection to combustion gases before a high-efficiency particulate collector. A combustion system was consisted with the fluidized bed reactor (starved air gasifier) and the secondary combustion chamber. As the dry absorbent was used a mixture of high reactive hydrated lime and activated carbon. Activated carbon content in the mixture was 5-10 % by mass. The absorbent was injected in the minimal recommended amount (4-5 kg/h). Applied collector was a ceramic filter with total filtration area of 120 m2 and guaranteed outlet …


Bayesian Approach To Average Power Calculations For Binary Regression Models With Misclassified Outcomes, Dunlei Cheng, James D. Stamey, Adam J. Branscum Dec 2008

Bayesian Approach To Average Power Calculations For Binary Regression Models With Misclassified Outcomes, Dunlei Cheng, James D. Stamey, Adam J. Branscum

Dunlei Cheng

We develop a simulation-based procedure for determining the required sample size in binomial regression risk assessment studies when response data are subject to misclassification. A Bayesian average power criterion is used to determine a sample size that provides high probability, averaged over the distribution of potential future data sets, of correctly establishing the direction of association between predictor variables and the probability of event occurrence. The method is broadly applicable to any parametric binomial regression model including, but not limited to, the popular logistic, probit, and complementary log-log models. We detail a common medical scenario wherein ascertainment of true disease …


Patent Citation Networks Revisited: Signs Of A Twenty-First Century Change, Katherine J. Strandburg, Gabor Csardi, Laszlo Zalanyi, Jan Tobochnik, Peter Erdi Dec 2008

Patent Citation Networks Revisited: Signs Of A Twenty-First Century Change, Katherine J. Strandburg, Gabor Csardi, Laszlo Zalanyi, Jan Tobochnik, Peter Erdi

Katherine J. Strandburg

This Article reports an empirical study of the network composed of patent “nodes” and citation “links” between them. It builds on an earlier study, in which we argued that trends in the growth of the patent citation network provide evidence that the explosive growth in patenting in the late twentieth century was due at least in part to the issuance of increasingly trivial patents. We defined a measure of patent stratification based on comparative probability of citation; an increase in this measure suggests that the USPTO is issuing patents of comparatively less technological significance. Provocatively, we found that stratification increased …


Appearance Of A Fractional Stokes-Einstein Relation In Water And A Structural Interpretation Of Its Onset, L. Xu, F. Mallamace, Z. Yan, Francis W. Starr, S. V. Buldyrev, H. E. Stanley Dec 2008

Appearance Of A Fractional Stokes-Einstein Relation In Water And A Structural Interpretation Of Its Onset, L. Xu, F. Mallamace, Z. Yan, Francis W. Starr, S. V. Buldyrev, H. E. Stanley

Francis Starr

The Stokes–Einstein relation has long been regarded as one of the hallmarks of transport in liquids. It predicts that the self-diffusion constant D is proportional to (τ/T)−1, where τ is the structural relaxation time and T is the temperature. Here, we present experimental data on water confirming that, below a crossover temperature T× ≈ 290 K, the Stokes– Einstein relation is replaced by a ‘fractional’ Stokes–Einstein relation D ∼ (τ/T)−ζ with ζ ≈ 3/5 (refs 1–6). We interpret the microscopic origin of this crossover by analysing the OH- stretch region of the Fourier transform infrared spectrum over a temperature range …


Slip Heterogeneity On A Corrugated Fault, Phillip G. Resor, Vanessa E. Meer Dec 2008

Slip Heterogeneity On A Corrugated Fault, Phillip G. Resor, Vanessa E. Meer

Phillip G Resor

Slip heterogeneity reflects the fundamental physics of earthquake rupture and has been attributed to strong fault patches termed asperities or barriers. We propose that variations in fault-surface orientation due to slip-parallel corrugations may act as geometric asperities and barriers, generating variations in incremental (i.e. due to a single earthquake) slip across a fault surface. We evaluate this hypothesis using observations from the Arkitsa normal fault exposure in central Greece. A scan of the Arkitsa fault surface with 1-m spatial resolution and mm-scale precision reveals corrugations made up of 1–5 m wide synforms, antiforms, and nearly planar fault sections with long …


Syllabus Of Mathematics For Economists (Master's Course), Reza Moosavi Mohseni Dr. Dec 2008

Syllabus Of Mathematics For Economists (Master's Course), Reza Moosavi Mohseni Dr.

Reza Moosavi Mohseni

No abstract provided.


When To Spray: A Time-Scale Calculus Approach To Controlling The Impact Of West Nile Virus, Diana Thomas, Marion Weedermann, Lora Billings, Joan Hoffacker, Robert A. Washington-Allen Dec 2008

When To Spray: A Time-Scale Calculus Approach To Controlling The Impact Of West Nile Virus, Diana Thomas, Marion Weedermann, Lora Billings, Joan Hoffacker, Robert A. Washington-Allen

Lora Billings

West Nile Virus (WNV) made its initial appearance in the New York City (NYC) metropolitan area in 1999 and was implicated in cases of human encephalitis and the extensive mortality in crows (Corvus sp.) and other avian species. Mosquitoes were found to be the primary vectors and NYC’s current policy on control strategies involved an eradication program that depends on the synchronicity of the summer mosquito population’s increases with the occurrence of cases in humans. The purpose of this paper is to investigate whether this is the most effective control strategy because past mathematical models assumed discrete behavior that …


Review Of Biocd Physics And Technology, David D. Nolte Dec 2008

Review Of Biocd Physics And Technology, David D. Nolte

David D Nolte

Spinning biodisks have advantages that make them attractive for specialized biochip applications. The two main classes of spinning biodisks are microfluidic disks and bio-optical compact disks BioCD. Microfluidic biodisks take advantage of noninertial pumping for lab-on-a-chip devices using noninertial valves and switches under centrifugal and Coriolis forces to distribute fluids about the disks. BioCDs use spinning-disk interferometry, under the condition of common-path phase quadrature, to perform interferometric label-free detection of molecular recognition and binding. The optical detection of bound molecules on a disk is facilitated by rapid spinning that enables high-speed repetitive sampling to eliminate 1/ f noise through common-mode …


Inverses Of Lower Triangular Toeplitz Matrices, William F. Trench Dec 2008

Inverses Of Lower Triangular Toeplitz Matrices, William F. Trench

William F. Trench

No abstract provided.


The Development Of Humans – A Study Including Languages, Cultures, Religions And Genetics, Dr. Erik Dahlquist, Dr. Allan Dahlquist Dec 2008

The Development Of Humans – A Study Including Languages, Cultures, Religions And Genetics, Dr. Erik Dahlquist, Dr. Allan Dahlquist

Dr. Erik Dahlquist

The book covers the development of culture, religion, language and genetics of the human population since prehistory. Four main cultures have spread around the globe: 1) Monosyllabic language people with ancestor cult 2) Austroasiatic people with sun worshipping and megalit graves. Counting with 20 as the base 3) Uralic speaking people with kings from the sky, and strong city states. Moon and mother godess. Don´t differentiate between male and female, he and she. 4) Inflectual language speaking people with sky gods and cattles. Indoeuropeans. Often endings differentiating he and she. Shows how original cultures are refelected in todays society.


On Nonautonomous Linear Systems Of Differential And Difference Equations With $R$-Symmetric Coefficient Matrices, William F. Trench Dec 2008

On Nonautonomous Linear Systems Of Differential And Difference Equations With $R$-Symmetric Coefficient Matrices, William F. Trench

William F. Trench

No abstract provided.


Problems Of Local Fractional Definite Integral Of The One-Variable Non-Differentiable Function, Yang Xiao-Jun Dec 2008

Problems Of Local Fractional Definite Integral Of The One-Variable Non-Differentiable Function, Yang Xiao-Jun

Xiao-Jun Yang

It is proposed that local fractional calculas introduced by Kolwankar and Gangal is extended by the concept of Jumarie’s fractional calculus and local fractional definite integral is redefined. The properties and the theorems of local fractional calculus are discussed in this paper.


Charles Patrick Daly, Karen M. Morin Dec 2008

Charles Patrick Daly, Karen M. Morin

Karen M. Morin

No abstract provided.


May 2009 East Coast Low Flood Warning Community Feedback Report, Neil Dufty Dec 2008

May 2009 East Coast Low Flood Warning Community Feedback Report, Neil Dufty

Neil Dufty

No abstract provided.


Synthesis Of Facial Amphiphile 3,7-Diamino-5Α-Cholestane Derivatives As A Molecular Receptor, Md Wasi Ahmad, Young Mee Jung, Sharaf Nawaz Khan, Hong Seok Kim Dec 2008

Synthesis Of Facial Amphiphile 3,7-Diamino-5Α-Cholestane Derivatives As A Molecular Receptor, Md Wasi Ahmad, Young Mee Jung, Sharaf Nawaz Khan, Hong Seok Kim

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

A series of facial amphiphiles 3,7-diaminocholestane were synthesized from 3,7-diketocholestane via 2 sequential reductive aminations and anion recognition was evaluated with acetate, chloride, bromide, fluoride and phosphate anions. The stereo-selective reductive amination protocol was utilized to synthesized facial amphiphiles afforded receptors in high yields. The molecular receptor 2 showed the highest binding constant with acetate in a 1:1 ratio.