Physical Sciences and Mathematics Commons^™

Sadc Challenges Country Water Partnerships To Make Impact, Stanley Mubako

Stanley Mubako

No abstract provided.

Environment-Friendly Organic Synthesis Using Bismuth Compounds. Bismuth Triflate Catalyzed Synthesis Of Substituted 3,4-Dihydro-2h-L-Benzopyrans, Ram S. Mohan, Mai P. Nguyen, Joshua N. Arnold, Katherine E. Peterson

Ram S. Mohan

Bismuth Compounds In Organic Synthesis. Bismuth Nitrate Catalyzed Chemoselective Synthesis Of Acylals From Aromatic Aldehydes, Ram S. Mohan, David H. Aggen, Joshua N. Arnold, Patrick D. Hayes, Nathaniel J. Smoter

Ram S. Mohan

Cortical Activation And Synchronization During Sentence Comprehension In High-Functioning Autism: Evidence Of Underconnectivity, Marcel Adam Just, Vladimir L. Cherkassky, Timothy A. Keller, Nancy J. Minshew

Marcel Adam Just

No abstract provided.

Spectral Densities Of Embedded Interfaces In Composite Materials, A. R. Mcgurn, Anthony Roy Day, D. J. Bergman, L. C. Davis, M. F. Thorpe

Anthony Roy Day

The effective resistivity and conductivity of two media that meet at a randomly rough interface are computed in the quasistatic limit. The results are presented in the spectral density representations of the Bergman-Milton formulation for the properties of two-component composite materials. The spectral densities are extracted from computer simulations of resistor networks in which the random interface separates two regions containing different types of resistors. In the limit that the bond lengths in the resistor network are small compared to parameters characterizing the surface roughness, the resistor network simulation approximates the continuum limit of the two-component composite. The Bergman-Milton formulation …

Dynamic Heterogeneities In Supercooled Water, Nicolas Giovambattista, Marco Mazza, Sergey V. Buldyrev, Francis W. Starr, H. Eugene Stanley

Francis Starr

No abstract provided.

Existence Of Solutions To A Hamiltonian System Without Convexity Condition On The Nonlinearity, Gregory S. Spradlin

Gregory S. Spradlin

Swarm-Mediated Cluster-Based Construction, S. Kazadi, J. Wigglesworth, A. Grosz, A. Lim, D. Vitullo

Sanza Kazadi

Modelling Dynamic Conditional Correlations In Wti Oil Forward And Futures Returns, Alessandro Lanza, Matteo Manera, Micheal Mcaleer

Matteo Manera

This paper estimates the dynamic conditional correlations in the returns on WTI oil onemonth forward prices, and one-, three-, six-, and twelve-month futures prices, using recently developed multivariate conditional volatility models. The dynamic correlations enable a determination of whether the forward and various futures returns are substitutes or complements, which are crucial for deciding whether or not to hedge against unforeseen circumstances. The models are estimated using daily data on WTI oil forward and futures prices, and their associated returns, from 3 January 1985 to 16 January 2004. At the univariate level, the estimates are statistically significant, with the occasional …

Using Dynamic Information In The Supply Network, Jeffrey Barker

Jeffrey Barker

No abstract provided.

An Inference Network Approach To Image Retrieval, Donald Metzler, R. Manmatha

R. Manmatha

Most image retrieval systems only allow a fragment of text or an example image as a query. Most users have more complex information needs that are not easily expressed in either of these forms. This paper proposes a model based on the Inference Network framework from information retrieval that employs a powerful query language that allows structured query operators, term weighting, and the combination of text and images within a query. The model uses non-parametric methods to estimate probabilities within the inference network. Image annotation and retrieval results are reported and compared against other published systems and illustrative structured and …

Using Maximum Entropy For Automatic Image Annotation, Jiwoon Jeon, R. Manmatha

R. Manmatha

In this paper, we propose the use of the Maximum Entropy approach for the task of automatic image annotation. Given labeled training data, Maximum Entropy is a statistical technique which allows one to predict the probability of a label given test data. The techniques allow for relationships between features to be effectively captured and has been successfully applied to a number of language tasks including machine translation. In our case, we view the image annotation task as one where a training data set of images labeled with keywords is provided and we need to automatically label the test images with …

Vapor Pressures And Vaporization Enthalpies Of The N-Alkanes From C21 To C30 At T ) 298.15 K By Correlation Gas Chromatography, James S. Chickos, William Hanshaw

James Chickos

No abstract provided.

Synthesis And Characterization Of A Novel 32-Membered Unsymmetrical Dinucleating [N12] Macrocycle: Preparation Of Bimetallic Complexes M2lx2(Clo4)2 (M = Zn, Cd Or Hg; X = Cl, Ncs Or No3), Z. A. Siddiqi Dr, Mohammad Mansoob Khan Dr

Dr. Mohammad Mansoob Khan

The condensation reaction of N-acetylaniline with 1,3-diaminopropane in 2 : 1 mole ratio under reflux condition generates an intermediate species having C55N bonds. The in situ reaction of the intermediate with HCHO and 1,3-diaminopropane in the presence of perchloric acid results in an off-white solid product. Analytical, FAB mass, IR, 1H NMR and electronic spectral data of this solid are consistent with the formation of the dihydroperchlorate salt of an unsymmetrical 32-membered [N12] macrocycle [L.2HClO4] via a capping mechanism of the intermediate species. Reactions of [L 2HClO4] with Group 12 metal salts, MX2, and their precursors, [M(Ph3P)2Cl2], produce bimetallic complexes …

Ensuring The Comparability Of Comparison Groups: Is Randomization Enough?, Vance Berger, Sherri Rose

Sherri Rose

It is widely believed that baseline imbalances in randomized trials must necessarily be random. In fact, there is a type of selection bias that can cause substantial, systematic and reproducible baseline imbalances of prognostic covariates even in properly randomized trials. It is possible, given complete data, to quantify both the susceptibility of a given trial to this type of selection bias and the extent to which selection bias appears to have caused either observable or unobservable baseline imbalances. Yet, in articles reporting on randomized trials, it is uncommon to find either these assessments or the information that would enable a …

Making Sustainable Development Happen: From Johannesburg To Albany, John C. Dernbach

John C. Dernbach

No abstract provided.

Fall Prevention Programs For The Elderly: A Bayesian Secondary Meta-Analysis, Joseph F. Lucke

Joseph Lucke

A secondary meta-analysis of programs to reduce falls in the elderly is undertaken to demonstrate a Bayesian analysis. The Bayesian statistical tradition is carefully distinguished from the standard Neyman-Pearson-Wald (NPW) statistical tradition. In the 12 studies, the logit effect size is used to compare treatment groups using a prevention program to control groups without a program. To contrast the Bayesian analysis, independent-effects and fixed-effect meta-analyses are first conducted in the NPW tradition. This is followed by Bayesian independent-effects and fixed-effect meta-analyses that numerically replicate the NPW results but have conceptually different interpretations. The final analyses comprise Bayesian random-effects and predictive …

Traveling Waves In Rotating Rayleigh-Bénard Convection: Analysis Of Modes And Mean Flow, Janet Scheel, M. Paul, P. Fishcer

Janet D. Scheel

Numerical simulations of the Boussinesq equations with rotation for realistic no-slip boundary conditions and a finite annular domain are presented. These simulations reproduce traveling waves observed experimentally. Traveling waves are studied near threshhold by using the complex Ginzburg-Landau equation (CGLE): a mode analysis enables the CGLE coefficients to be determined. The CGLE coefficients are compared with previous experimental and theoretical results. Mean flows are also computed and found to be more significant as the Prandtl number decreases (from σ=6.4 to σ=1). In addition, the mean flow around the outer radius of the annulus appears to be correlated with the mean …

Magnetic And Transport Properties Of The V2– Vi3 Diluted Magnetic Semiconductor Sb2_Xmnxte3, Jeffrey Dyck, P. Svanda, P. Lostak, J. Horak, W. Chen, C. Uher

Jeffrey Dyck

We have measured electrical and magnetic properties of single crystals of Sb2_xMnxTe3 with x =0 – 0.045 at temperatures of 2 K to 300 K. Hall effect measurements indicate that each manganese atom donates approximately one hole to the valence band. The magnetic susceptibility is paramagnetic down to 2 K, and both Curie–Weiss and Brillouin analyses show that manganese substitutes for Sb and takes the Mn2+ state with S=5/2. Contrary to the case of III–V host matrices, manganese does not stimulate ferromagnetic order in the family of bulk layered V2– VI3 diluted magnetic semiconductors, at least in the range of …

Decoupling Of Erosion And Precipitation In The Himalayas, D Burbank, Ann Blythe, J Putkonen, B Pratt-Sitaula, E Gabet, M Oskin, A Barros, T Ohja

Ann Blythe

The hypothesis that abrupt spatial gradients in erosion can cause high strain rates in active orogens has been supported by numerical models that couple erosional processes with lithospheric deformation via gravitational feedbacks1, 2, 3. Most such models invoke a 'stream-power' rule, in which either increased discharge or steeper channel slopes cause higher erosion rates. Spatial variations in precipitation and slopes are therefore predicted to correlate with gradients in both erosion rates and crustal strain. Here we combine observations from a meteorological network across the Greater Himalaya, Nepal, along with estimates of erosion rates at geologic timescales (greater than 100,000 yr) …

Modeling The Optimum Duration Of Antibiotic Prophylaxis In An Anthrax Outbreak, Ron Brookmeyer, Elizabeth Johnson, Robert Bollinger

Ron Brookmeyer

A critical consideration in effective and measured public health responses to an outbreak of inhalational anthrax is the optimum duration of antibiotic prophylaxis. We develop a competing-risks model to address the duration of antibiotic prophylaxis and the incubation period that accounts for the risks of spore germination and spore clearance. The model predicts the incubation period distribution, which is confirmed by empirical data. The optimum duration of antibiotic prophylaxis depends critically on the dose of inhaled spores. At high doses, we show that exposed persons would need to remain on antibiotic prophylaxis for at least 4 months, and considerable morbidity …

Statistical Models And Bioterrorism: Application To The U.S. Anthrax Outbreak, Ron Brookmeyer, Natalie Blades

Ron Brookmeyer

In the fall of 2001 an outbreak of inhalational anthrax occurred in the United States that was the result of bioterrorism. Letters contaminated with anthrax spores were sent through the postal system. In response to the outbreak, public health officials treated over 10,000 persons with antibiotic prophylaxis in the hopes of preventing further morbidity and mortality. No persons receiving the antibiotics subsequently developed disease. The question arises as to how many cases of disease may actually have been prevented by the public health intervention of antibiotic prophylaxis. A statistical model is developed to answer this question by relating to the …

An Open Framework Supporting Multimedia Web Services, Jia Zhang, Jen-Yao Chung

Jia Zhang

No abstract provided.

Non-Steady-State Approach #11;To Steady-State Kinetics: #11;Case Study Of H2s Oxidation By Oxygen, Andrey N. Zagoruiko, Vladimir V. Mokrinskii

Andrey N Zagoruiko

Non-steady-state kinetic models may be used for treatment of steady-state kinetic data in case when algebraic elaboration of steady-state kinetic equations is impossible or complicated. The proposed approach includes numerical integration of time-dependent differential equations until achievement of steady-state, resulting in possibility to numerically obtain the rate values for separate reaction stages for given composition of reaction mixture. The obtained non-steady-state model may be then applied in simulation of catalyst pellets and catalyst beds in research and engineering purposes. The case study demonstrates application of such approach for steady-state kinetic description of complicated reaction system of H2S oxidation by oxygen. …

Mockup-Driven Fast Prototyping Methodology For Web Requirements Engineering, Jia Zhang, Carl Chang, Jen-Yao Chung

Jia Zhang

No abstract provided.

Using Information Literacy Standards To Improve Geoscience Courses, Aimee Dechambeau, Ira Sasowsky

Aimee deChambeau

Information literacy (IL) is the set of skills that enables a person to find, evaluate, and use information. Although IL is important in the geosciences, it is hard to teach because the information comes in so many forms. Most geoscience courses include work that implicitly addresses some IL issues. However, because of the importance of IL, it is worthwhile to explicitly include it as part of the curriculum. The Association of College and Research Libraries has developed Information Literacy Standards for Higher Education that may be used to assess an individual's level of information literacy. We introduce a method for …

Mediating Electronic Meetings, Jia Zhang, Carl Chang, Jen-Yao Chung

Jia Zhang

No abstract provided.

Assessment Of Model Development Techniques And Evaluation Methods For Binary Classification In The Credit Industry, Satish Nargundkar, Jennifer Priestley

Jennifer L. Priestley

We examine and compare the most prevalent modeling techniques in the credit industry, Linear Discriminant Analysis, Logistic Analysis and the emerging technique of Neural Network modeling. K-S Tests and Classification Rates are typically used in the industry to measure the success in predictive classification. We examine those two methods and a third, ROC Curves, to determine if the method of evaluation has an influence on the perceived performance of the modeling technique. We found that each modeling technique has its own strengths, and a determination of the “best” depends upon the evaluation method utilized and the costs associated with misclassification.

Absorptive Capacity, Causal Ambiguity And Outcome Ambiguity: The Network Effect And Knowledge Transfer Difficulty Among Four Network Forms, Subhashish Samaddar, Jennifer Priestley

Jennifer L. Priestley

No abstract is currently available.

Light Propagation In Variable-Refractive-Index Materials With Liquid-Crystal-Infiltrated Microcavities, Bin Wang, Philip Bos, Charles D. Hoke

Philip J. Bos

A liquid-crystal-infiltrated microcavity structure is proposed as a variable-refractive-index material. It has the advantages over previously considered nanostructured materials of having a larger phase-angle change and lower driving voltage. Two-dimensional liquid-crystal director and finite-difference time-domain optical simulations are used to select liquid crystal material parameters and optimize the dimension of the microcavity structured material.