Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

2012

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 12061 - 12090 of 12196

Full-Text Articles in Physical Sciences and Mathematics

Polyelectrolyte Complex Materials Consisting Of Antibacterial And Cell-Supporting Layers, Khairul Mat Amin, Kerry Gilmore, Jake Matic, Stephen Poon, Mark Walker, Mark Wilson, Marc In Het Panhuis Dec 2011

Polyelectrolyte Complex Materials Consisting Of Antibacterial And Cell-Supporting Layers, Khairul Mat Amin, Kerry Gilmore, Jake Matic, Stephen Poon, Mark Walker, Mark Wilson, Marc In Het Panhuis

Mark R Wilson

The characterization of a polyelectrolyte complex material comprised of two biopolymers, a chitosan upper layer and a gellan gum under layer, is reported. It is shown that the upper layer of chitosan with incorporated levofloxacin displays an antibacterial activity, while the under layer of a gellan gum/TiO2 composite supports the growth of fibroblastic cells.

Go to article

Sex-Specific Sod Levels And Dna Damage In Painted Dragon Lizards (Ctenophorus Pictus), Mats Olsson, Mo Healey, Cecile Perrin, Mark Wilson, Michael Tobler Dec 2011

Sex-Specific Sod Levels And Dna Damage In Painted Dragon Lizards (Ctenophorus Pictus), Mats Olsson, Mo Healey, Cecile Perrin, Mark Wilson, Michael Tobler

Mark R Wilson

When groups of individuals differ in activities that may influence the production of reactive molecules, such as superoxide, we expect selection to result in congruent upregulation of antioxidant production in the group(s) most at risk of suffering concomitant erosion of essential tissue and biomolecules, such as DNA. We investigate this in a (near) annual lizard species, the Australian painted dragon (Ctenophorus pictus), in which males and females have fundamentally different lifestyles, with males being overtly conspicuous and aggressive, whereas females are placid and camouflaged. When kept in identical conditions to females in captivity, males had higher levels of superoxide dismutase …

Go to article

Testing For Regime Swtiching: A Comment, Douglas Steigerwald, Andrew Carter Dec 2011

Testing For Regime Swtiching: A Comment, Douglas Steigerwald, Andrew Carter

Douglas G. Steigerwald

An autoregressive model with Markov-regime switching is analyzed that reflects on the properties of the quasi-likelihood ratio test developed by Cho and White (2007). For such a model, we show that consistency of the quasi-maximum likelihood estimator for the population parameter values, on which consistency of the test is based, does not hold. We describe a condition that ensures consistency of the estimator and discuss the consistency of the test in the absence of consistency of the estimator.

Go to article

Avoiding Colored Partitions Of Two Elements In The Pattern Sense, Adam Goyt, Lara Pudwell Dec 2011

Avoiding Colored Partitions Of Two Elements In The Pattern Sense, Adam Goyt, Lara Pudwell

Lara K. Pudwell

No abstract provided.

Go to article

Beyond Cell Penetrating Peptides: Designed Molecular Transporters, Paul Wender, Christina Cooley, Erika Geihe Dec 2011

Beyond Cell Penetrating Peptides: Designed Molecular Transporters, Paul Wender, Christina Cooley, Erika Geihe

Christina B Cooley

Inspired originally by peptides that traverse biological barriers, research on molecular transporters has since identified the key structural requirements that govern cellular entry, leading to new, significantly more effective and more readily available agents. These new drug delivery systems enable or enhance cellular and tissue uptake, can be targeted and provide numerous additional advantages of significance in imaging, diagnostics and therapy.

Go to article

John Goodricke, Edward Pigott, And Their Work On Variable Stars, Linda French Dec 2011

John Goodricke, Edward Pigott, And Their Work On Variable Stars, Linda French

Linda French

John Goodricke and Edward Pigott, working in York, England, between 1781 and 1786, determined the periods of variation of eclipsing binaries such as b Persei (Algol) and b Lyrae and speculated that the eclipses of Algol might be caused by a “dark body,” perhaps even a planet. They also determined the periods of variation of the first two known Cepheid variables, the stars whose period-luminosity relation today enables astronomers to determine distances to distant galaxies. Goodricke holds special interest because he was completely deaf and because he died at the age of 21. The lives and work of these two …

Go to article

Predictors Of Telomere Content In Dragon Lizards, Cissy Ballen, Mo Healey, Mark Wilson, Michael Tobler, Mats Olsson Dec 2011

Predictors Of Telomere Content In Dragon Lizards, Cissy Ballen, Mo Healey, Mark Wilson, Michael Tobler, Mats Olsson

Mark R Wilson

Telomeres shorten as a consequence of DNA replication, in particular in cells with low production of telomerase and perhaps in response to physiological stress from exposure to reactive oxygen species, such as superoxide. This process of telomere attrition is countered by innate antioxidation, such as via the production of superoxide dismutase. We studied the inheritance of telomere length in the Australian painted dragon lizard (Ctenophorus pictus) and the extent to which telomere length covaries with masscorrected maternal reproductive investment, which reflects the level of circulating yolk precursor and antioxidant, vitellogenin. Our predictors of offspring telomere length explained 72 % of …

Go to article

Pattern Avoidance In Ternary Trees, Nathan Gabriel, Katie Peske, Lara Pudwell, Sam Tay Dec 2011

Pattern Avoidance In Ternary Trees, Nathan Gabriel, Katie Peske, Lara Pudwell, Sam Tay

Lara K. Pudwell

This paper considers the enumeration of ternary trees (i.e., rooted ordered trees in which each vertex has 0 or 3 children) avoiding a contiguous ternary tree pattern. We begin by finding recurrence relations for several simple tree patterns; then, for more complex trees, we compute generating functions by extending a known algorithm for pattern-avoiding binary trees. Next, we present an alternate one-dimensional notation for trees which we use to find bijections that explain why certain pairs of tree patterns yield the same avoidance generating function. Finally, we compare our bijections to known “replacement rules” for binary trees and generalize these …

Go to article

Book Review: Biology Of The Sauropod Dinosaurs: Understanding The Lives Of Giants, Kristi Curry Rogers Dec 2011

Book Review: Biology Of The Sauropod Dinosaurs: Understanding The Lives Of Giants, Kristi Curry Rogers

Kristi Curry Rogers

No abstract provided.

Go to article

Derivation Of The Binary Mass Function, Eric Addison Dec 2011

Derivation Of The Binary Mass Function, Eric Addison

Eric Addison

The observational quantity f(m), the binary mass function, is derived.

Go to article

C60 Oxide As A Key Component Of Aqueous C60 Colloidal Suspensions, Befrika Murdianti, Joshua Damron, Martha Hilburn, Randall Maples, Rangika Hikkaduwa Koralege, Sathish Kuriyavar, Kevin Ausman Dec 2011

C60 Oxide As A Key Component Of Aqueous C60 Colloidal Suspensions, Befrika Murdianti, Joshua Damron, Martha Hilburn, Randall Maples, Rangika Hikkaduwa Koralege, Sathish Kuriyavar, Kevin Ausman

Kevin D. Ausman

Stable aqueous fullerene colloidal suspensions (nC60) are demonstrated to rely on the [6,6]-closed epoxide derivative of the fullerene (C60O) for stability. This derivative is present, though often unrecognized, in small quantities in nearly all C60 starting materials due to a reaction with air. The low-yield formation of nC60 from organic solvent solutions results from a preferential partitioning and thus enrichment of C60O in the colloidal particles. This partitioning is significantly retarded in the nC60 synthesis method that does not involve organic solvent solutions: long-term stirring in water. Instead, this method relies on trace levels of ozone in the ambient atmosphere …

Go to article

Pmma-Libob Gel Electrolyte For Application In Lithium Ion Batteries, Siti Rohana Majid, Kufian M. Z., Aziz M. F., Shukur M. F., Rahim A. S., Ariffin N. E., Shuhaimi N. E. A., Yahya R., Arof A. K. Dec 2011

Pmma-Libob Gel Electrolyte For Application In Lithium Ion Batteries, Siti Rohana Majid, Kufian M. Z., Aziz M. F., Shukur M. F., Rahim A. S., Ariffin N. E., Shuhaimi N. E. A., Yahya R., Arof A. K.

Siti Rohana Majid

Different amounts of lithium bis(oxalato) borate (LiBOB) have been added into a mixture of equal weights of ethylene carbonate (EC) and propylene carbonate (PC). The variation of molar conductivity of the LiBOB based liquid electrolyte with square root of salt concentration obeys the weak electrolyte theory. The 0.6 M LiBOB in EC/PC liquid electrolyte with highest room temperature conductivity of 4.8 mS cm(-1) was chosen for further work. 10 to 50 wt.% PMMA was added to this composition and heated between 343 and 353 K for 20 min to obtain the gel polymer electrolytes (GPEs). Due to its dry state …

Go to article

A Comparative Analysis Of Decision Trees Vis-À-Vis Other Computational Data Mining Techniques In Automotive Insurance Fraud Detection, Adrian Gepp, Kuldeep Kumar, J Holton Wilson, Sukanto Bhattacharya Dec 2011

A Comparative Analysis Of Decision Trees Vis-À-Vis Other Computational Data Mining Techniques In Automotive Insurance Fraud Detection, Adrian Gepp, Kuldeep Kumar, J Holton Wilson, Sukanto Bhattacharya

Adrian Gepp

No abstract provided.

Go to article

Nanoscale Toughness And Behavior Of Graphene/Epoxy Interfaces, Nima Rahbar, Hossein Salahshoor Dec 2011

Nanoscale Toughness And Behavior Of Graphene/Epoxy Interfaces, Nima Rahbar, Hossein Salahshoor

Nima Rahbar

Atomistic simulations are performed to investigate the nano-scale interfacial fracture toughness between graphene and epoxy. Nano-mechanical properties of graphene and epoxy are initially studied using molecular dynamics simulations. A novel method is suggested to accurately model the behavior of the graphen/epoxy interface during the curing process of the epoxy as a function of temperature. The computed interfacial fracture energy is computed at about 0.203 J/m2, which is in good agreement with available experimental data. It is also shown that the adhesion between cured epoxy and graphene layer increases the pre-existing waviness of the 2-dimensional graphene sheet in a 3-dimensional space. …

Go to article

Introduction To Adobe Dreamweaver, Christy Allen Dec 2011

Introduction To Adobe Dreamweaver, Christy Allen

Christy Allen

No abstract provided.

Go to article

Toward Unification Of Exact And Heuristic Optimization Methods, John Hooker Dec 2011

Toward Unification Of Exact And Heuristic Optimization Methods, John Hooker

John Hooker

No abstract provided.

Go to article

Implementation Of The Vortex Force Formalism In The Coupled Ocean-Atmosphere-Wave-Sediment Transport (Coawst) Modeling System For Inner Shelf And Surf Zone Applications., Nirnimesh Kumar, George Voulgaris, John Warner, Maitane Olabarietta Dec 2011

Implementation Of The Vortex Force Formalism In The Coupled Ocean-Atmosphere-Wave-Sediment Transport (Coawst) Modeling System For Inner Shelf And Surf Zone Applications., Nirnimesh Kumar, George Voulgaris, John Warner, Maitane Olabarietta

George Voulgaris

No abstract provided.

Go to article

Induced Subgraphs Of Johnson Graphs, Ramin Naimi, Jeffrey Shaw Dec 2011

Induced Subgraphs Of Johnson Graphs, Ramin Naimi, Jeffrey Shaw

Ramin Naimi

The Johnson graph J(n,N) is defined as the graph whose vertices are the n-subsets of the set {1,2,...,N}, where two vertices are adjacent if they share exactly n - 1 elements. Unlike Johnson graphs, induced subgraphs of Johnson graphs (JIS for short) do not seem to have been studied before. We give some necessary conditions and some sufficient conditions for a graph to be JIS, including: in a JIS graph, any two maximal cliques share at most two vertices; all trees, cycles, and complete graphs are JIS; disjoint unions and Cartesian products of JIS graphs are JIS; every JIS graph …

Go to article

A Historical Usage-Based Approach Supporting Scientific Service Reuse, Jia Zhang, John Alexandar, Wei Tan, Ian Foster, Ravi Madduri, Carole Goble Dec 2011

A Historical Usage-Based Approach Supporting Scientific Service Reuse, Jia Zhang, John Alexandar, Wei Tan, Ian Foster, Ravi Madduri, Carole Goble

Jia Zhang

No abstract provided.

Go to article

Graphene Oxide And Its Electrochemical Performance, Siti Rohana Majid, Ban F. Y., Huang N. M., Lim H. N. Dec 2011

Graphene Oxide And Its Electrochemical Performance, Siti Rohana Majid, Ban F. Y., Huang N. M., Lim H. N.

Siti Rohana Majid

In this study, graphene oxide (GO) was synthesized from graphite flakes using simplified Hummer's method. Field Emission Scanning Electron Microscopy (FESEM) image showed that the GO nanosheets had an average area 7000 mu m(2) with lateral dimension of up to 150 mu m. The X-Ray Diffraction (XRD) pattern revealed a (002) diffraction peak, signifying the successful synthesis of GO. GO solution was cast on an aluminum (Al) foil placed in a petri dish and left to dry to form an electrode made up of GO film on the Al foil (GO-Al). It was found that GO-Al exhibited equivalent series resistance …

Go to article

Note On The Unbiased Estimation Of A Function Of The Parameter Of The Geometric Distribution, Tamas Lengyel Dec 2011

Note On The Unbiased Estimation Of A Function Of The Parameter Of The Geometric Distribution, Tamas Lengyel

Tamas Lengyel

Kolmogorov studied the problem of whether a function of the parameter p of the Bernoulli distribution Bernoulli[p] has an unbiased estimator based on a sample X1,X2,...,Xn of size n and proved that exactly the polynomial functions of degree at most n can be estimated. For the geometric distribution Geometric[p], we prove that exactly the functions that are analytic at p = 1 have unbiased estimators and present the best estimators.

Go to article

A Significant Component Of Ageing (Dna Damage) Is Reflected In Fading Breeding Colors: An Experimental Test Using Innate Antioxidant Mimetics In Painted Dragon Lizards, Mats Olsson, Michael Tobler, Mo Healey, Cecile Perrin, Mark Wilson Dec 2011

A Significant Component Of Ageing (Dna Damage) Is Reflected In Fading Breeding Colors: An Experimental Test Using Innate Antioxidant Mimetics In Painted Dragon Lizards, Mats Olsson, Michael Tobler, Mo Healey, Cecile Perrin, Mark Wilson

Mark R Wilson

A decade ahead of their time, von Schantz et al. united sexual selection and free radical biology by identifying causal links between deep-rooted physiological processes that dictate resistance to toxic waste from oxidative metabolism (reactive oxygen species, ROS), and phenotypic traits, such as ornaments.Ten years later, these ideas have still only been tested with indirect estimates of free radical levels (oxidative stress) subsequent to the action of innate and dietary antioxidants. Here, we measure net superoxide (a selection pressure for antioxidant production) and experimentally manipulate superoxide antioxidation using a synthetic mimetic of superoxide dismutase (SOD), Eukarion 134 (EUK). We then …

Go to article

Amyloid-Β Oligomers Are Sequestered By Both Intracellular And Extracellular Chaperones, P Narayan, Sarah Meehan, John Carver, Mark Wilson, C M Dobson, D Klenerman Dec 2011

Amyloid-Β Oligomers Are Sequestered By Both Intracellular And Extracellular Chaperones, P Narayan, Sarah Meehan, John Carver, Mark Wilson, C M Dobson, D Klenerman

Mark R Wilson

The aberrant aggregation of the amyloid-β peptide into β-sheet rich, fibrillar structures proceeds via a heterogeneous ensemble of oligomeric intermediates that have been associated with neurotoxicity in Alzheimer’s disease (AD). Of particular interest in this context are the mechanisms by which molecular chaperones, part of the primary biological defenses against protein misfolding, influence Aβ aggregation. We have used single-molecule fluorescence techniques to compare the interactions between distinct aggregation states (monomers, oligomers, and amyloid fibrils) of the AD-associated amyloid-β(1–40) peptide, and two molecular chaperones, both of which are upregulated in the brains of patients with AD and have been found colocalized …

Go to article

Synthesis Of Anion Binding Molecules: Potential Chemical Sensors, Ronald Brisbois, S. Larson, L. Erickson, H. Haley Dec 2011

Synthesis Of Anion Binding Molecules: Potential Chemical Sensors, Ronald Brisbois, S. Larson, L. Erickson, H. Haley

Ronald Brisbois

No abstract provided.

Go to article

Investigating Cognitive Task Difficulties And Expert Skills In E-Learning Storyboards Using A Cognitive Task Analysis Technique, Siti Salwah Salim Dec 2011

Investigating Cognitive Task Difficulties And Expert Skills In E-Learning Storyboards Using A Cognitive Task Analysis Technique, Siti Salwah Salim

Siti Salwah Salim Prof. Dr.

E-learning storyboards have been a useful approach in distance learning development to support interaction between instructional designers and subject-matter experts. Current works show that researchers are focusing on different approaches for use in storyboards, and there is less emphasis on the effect of design and process difficulties faced by instructional designers and subject-matter experts. This study explores problem aspects of the cognitive task and the skills required of subject-matter experts by applying a cognitive task analysis approach from the expert point of view. The result shows that subject-matter experts face difficulties in making decisions on three elements during e-learning course …

Go to article

Photometry Of 17 Jovian Trojan Asteroids, Linda French, Robert Stephens, Daniel Coley, Ralph Megna Dec 2011

Photometry Of 17 Jovian Trojan Asteroids, Linda French, Robert Stephens, Daniel Coley, Ralph Megna

Linda French

Lightcurves for 17 Jupiter Trojan asteroids were obtained from Cerro Tololo Interamerican Observatory, Lowell Observatory, and GMARS Observatory from 2010 August to 2012 March.

Go to article

Temporal And Spatial Variability Of Aeolian Sand Transport: Implications For Field Measurements, Jean Ellis, Douglas Sherman, Eugene Farrell, Bailiang Li Dec 2011

Temporal And Spatial Variability Of Aeolian Sand Transport: Implications For Field Measurements, Jean Ellis, Douglas Sherman, Eugene Farrell, Bailiang Li

Jean Taylor Ellis

No abstract provided.

Go to article

Short-Period Gravity Waves Over Alaska, Michael Negale Dec 2011

Short-Period Gravity Waves Over Alaska, Michael Negale

Michael Negale

The propagation nature and sources of short-period gravity waves have been studied extensively at low and mid-latitudes, while their extent and nature at the polar regions are less known. During the last decade, observations from select sites on the Antarctic continent have revealed a significant presence of these waves over the southern Polar Region as well as shown unexpected dynamical behavior. In contrast, observations over the Arctic region are few and the dynamical behavior is unknown. A recent project was initiated in January 2011 to investigate the presence and dynamics of these waves over interior Alaska. This site provides an …

Go to article

Partially Hyperbolic Sets With Positive Measure And Acip For Partially Hyperbolic Systems, Pengfei Zhang Dec 2011

Partially Hyperbolic Sets With Positive Measure And Acip For Partially Hyperbolic Systems, Pengfei Zhang

Pengfei Zhang

No abstract provided.

Go to article

Environmentally Friendly Organic Synthesis Using Bismuth(Iii) Compounds, Ram Mohan, Scott Krabbe Dec 2011

Environmentally Friendly Organic Synthesis Using Bismuth(Iii) Compounds, Ram Mohan, Scott Krabbe

Ram S. Mohan

Abstract With increasing environmental concerns, the need for environmentally friendly organic synthesis has gained increased importance. In this regard, bismuth (III) compounds are especially attractive as “green” reagents and catalysts for organic synthesis. Bismuth(III) compounds are remarkably nontoxic, relatively air and moisture stable, and easy to handle. The contributions from our laboratory in the last 5 years in the field of applications of bismuth(III) compounds as catalysts are presented.

Go to article

First Prev Next Last