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Articles 15481 - 15510 of 16838

Full-Text Articles in Physical Sciences and Mathematics

Targets, Timetables And Effective Implementing Mechanisms: Necessary Building Blocks For Sustainable Development, John C. Dernbach Dec 2004

Targets, Timetables And Effective Implementing Mechanisms: Necessary Building Blocks For Sustainable Development, John C. Dernbach

John C. Dernbach

No abstract provided.


Integrating High-Precision Aftershock Locations And Geodetic Observations To Model Coseismic Deformation Associated With The 1995 Kozani-Grevena Earthquake, Greece, Phillip G. Resor, David Pollard, T J. Wright, G C. Beroza Dec 2004

Integrating High-Precision Aftershock Locations And Geodetic Observations To Model Coseismic Deformation Associated With The 1995 Kozani-Grevena Earthquake, Greece, Phillip G. Resor, David Pollard, T J. Wright, G C. Beroza

Phillip G Resor

We integrate high-precision aftershock locations with geodetic inverse modeling to create a more complete kinematic model for the Kozani-Grevena earthquake sequence. Using the double-difference algorithm, we have improved relative hypocentral locations by a factor of ∼7 and thus imaged the details of the fault network associated with the seismic sequence. The interpreted fault network consists of multiple segments including (1) a master normal fault that strikes nearly due west and dips toward the north at 43°, extending from 6 to 15 km depth; (2) an upper segment that connects the top of the seismicity to the observed surface ruptures and …


Advances In High Resolution Imaging From Underwater Vehicles, Hanumant Singh, Christopher Roman, Oscar Pizarro, Ryan Eustice Dec 2004

Advances In High Resolution Imaging From Underwater Vehicles, Hanumant Singh, Christopher Roman, Oscar Pizarro, Ryan Eustice

Christopher N. Roman

Large area mapping at high resolution underwater continues to be constrained by the mismatch between available navigation as compared to sensor accuracy. In this paper we present advances that exploit consistency and redundancy within local sensor measurements to build high resolution optical and acoustic maps that are a consistent representation of the environment.

We present our work in the context of real world data acquired using Autonomous Underwater Vehicles (AUVs) and Remotely Operated Vehicles (ROVs) working in diverse applications including shallow water coral reef surveys with the Seabed AUV, a forensic survey of the RMS Titanic in the North Atlantic …


Multilevel Matrices With Involutory Symmetries And Skew Symmetries, William F. Trench Dec 2004

Multilevel Matrices With Involutory Symmetries And Skew Symmetries, William F. Trench

William F. Trench

No abstract provided.


Environment Friendly Organic Synthesis Using Bismuth Compounds. An Efficient Method For Carbonyl-Ene Reactions Catalyzed By Bismuth Triflate, Ram S. Mohan, Erin D. Anderson, Justin J. Ernat, Mai P. Nguyen, Ann C. Palma Dec 2004

Environment Friendly Organic Synthesis Using Bismuth Compounds. An Efficient Method For Carbonyl-Ene Reactions Catalyzed By Bismuth Triflate, Ram S. Mohan, Erin D. Anderson, Justin J. Ernat, Mai P. Nguyen, Ann C. Palma

Ram S. Mohan

Bismuth triflate (0.1 mol %) is a highly efficient catalyst for the cyclization of citronellal 1, a reaction that yields a ratio of 80:20 of isopulegol 2 and neoisopulegol 3. This methodology has also been extended to the synthesis of substituted piperidines. The bismuth triflate catalyzed ene reaction of aldehyde 4 gives a 70:30 mixture of piperidines 5 and 6. The advantages of these methods include the use of a highly efficient catalyst that is relatively nontoxic, cheap and easy to handle.


A Study Of Epoxyolefin Cyclizations Catalyzed By Bismuth Trifluoromethanesulfonate And Other Metal Triflates, Ram S. Mohan, Joshua R. Lacey, Peter W. Anzalone, Christopher M. Duncan, Matthew J. Hackert Dec 2004

A Study Of Epoxyolefin Cyclizations Catalyzed By Bismuth Trifluoromethanesulfonate And Other Metal Triflates, Ram S. Mohan, Joshua R. Lacey, Peter W. Anzalone, Christopher M. Duncan, Matthew J. Hackert

Ram S. Mohan

Epoxyolefin cyclizations have attracted considerable interest due to their importance in biosynthetic pathways. Bismuth trifluoromethanesulfonate as well as several other metal triflates are shown to be highly effective (0.1 mol %) catalysts for the cyclization of geraniolene oxide. The product composition is found to be more dependent on solvent and substrate concentration than on the nature of the metal triflate. Cyclization products are favored in CH2Cl2 and under high dilution conditions. Ether solvents favored acyclic products.


The Discovery-Oriented Approach To Organic Chemistry. 6. Selective Reduction In Organic Chemistry: Reduction Of Aldehydes In The Presence Of Esters Using Sodium Borohydride, Ram S. Mohan, Ashvin R. Baru Dec 2004

The Discovery-Oriented Approach To Organic Chemistry. 6. Selective Reduction In Organic Chemistry: Reduction Of Aldehydes In The Presence Of Esters Using Sodium Borohydride, Ram S. Mohan, Ashvin R. Baru

Ram S. Mohan

Chemoselective reductions are valuable in organic synthesis and are routinely discussed in a sophomore organic chemistry course. Yet, there are few examples of laboratory experiments that illustrate such chemoselectivity. A reaction that is routinely discussed in sophomore organic chemistry is the selective reduction of aldehydes and ketones using sodium borohydride. Esters are typically not affected by NaBH4. However, none of the lab experiments reported to date illustrate this chemoselectivity (1). We have developed a discovery-oriented lab experiment that illustrates the chemoselective nature of reductions using sodium borohydride. The experiments involve the reduction of vanillin acetate (Scheme I) and methyl …


Efficient Population Registration Of 3d Data, Lilla Zöllei, Erik G. Learned-Miller, Eric Grimson, William Wells Dec 2004

Efficient Population Registration Of 3d Data, Lilla Zöllei, Erik G. Learned-Miller, Eric Grimson, William Wells

Erik G Learned-Miller

We present a population registration framework that acts on large collections or populations of data volumes. The data alignment procedure runs in a simultaneous fashion, with every member of the population approaching the central tendency of the collection at the same time. Such a mechanism eliminates the need for selecting a particular reference frame a priori, resulting in a non-biased estimate of a digital atlas. Our algorithm adopts an affine congealing framework with an information theoretic objective function and is optimized via a gradientbased stochastic approximation process embedded in a multi-resolution setting. We present experimental results on both synthetic and …


Classification Models For Historical Manuscript Recognition, S. L. Feng, R. Manmatha Dec 2004

Classification Models For Historical Manuscript Recognition, S. L. Feng, R. Manmatha

R. Manmatha

This paper investigates different machine learning models to solve the historical handwritten manuscript recognition problem. In particular, we test and compare support vector machines, conditional maximum entropy models and Naive Bayes with kernel density estimates and explore their behaviors and properties when solving this problem. We focus on a whole word problem to avoid having to do character segmentation which is difficult with degraded handwritten documents. Our results on a publicly available standard dataset of 20 pages of George Washington's manuscripts show that Naive Bayes with Gaussian kernel density estimates significantly outperforms the other models and prior work using hidden …


An Explicit Fusion Algebra Isomorphism For Twisted Quantum Doubles Of Finite Groups, Christopher Goff Dec 2004

An Explicit Fusion Algebra Isomorphism For Twisted Quantum Doubles Of Finite Groups, Christopher Goff

Christopher Goff

We exhibit an isomorphism between the fusion algebra of the quantum double of an extraspecial p-group, where p is an odd prime, and the fusion algebra of a twisted quantum double of an elementary abelian group of the same order.


The $\Alpha$ And The $\Omega$ Of Congeneric Test Theory: An Extension Of Reliability And Internal Consistency To Heterogeneous Tests, Joseph F. Lucke Dec 2004

The $\Alpha$ And The $\Omega$ Of Congeneric Test Theory: An Extension Of Reliability And Internal Consistency To Heterogeneous Tests, Joseph F. Lucke

Joseph Lucke

Psychometric theory focuses primarily on tests that are homogeneous, that measure only one attribute of a psychosocial entity. However, the complexity of psychosocial behavior often requires tests that are heterogeneous, that measure more than one attribute. In this presentation, reliability and internal consistency are extended to heterogeneous tests under the rubric of congeneric test theory. The extensions show that reliability and internal consistency have very similar properties. Reliability and internal consistency are shown to be unique up to a linear transformation. Whereas internal consistency is a lower bound to reliability in the homogeneous case, it is a strict lower bound …


Are Credit Constraints In Italy Really More Binding In The South?, Claudio Lupi Dec 2004

Are Credit Constraints In Italy Really More Binding In The South?, Claudio Lupi

Claudio Lupi

This paper is motivated by a very practical question: are there significant geographical differences in the accessibility to the credit market on the part of Italian households? The investigation is carried using robust probit model. Estimation is carried out in a Bayesian framework. The results are somewhat surprising, showing that the area where households are more likely to be credit constrained is not the South, as could be easily imagined, but rather the highly developed and industrialized North-West.


Sign Classification Using Local And Meta-Features, Marwan A. Mattar,, Allen R. Hanson,, Erik G. Learned-Miller Dec 2004

Sign Classification Using Local And Meta-Features, Marwan A. Mattar,, Allen R. Hanson,, Erik G. Learned-Miller

Erik G Learned-Miller

Our world is populated with visual information that a sighted person makes use of daily. Unfortunately, the visually impaired are deprived from such information, which limits their mobility in unconstrained environments. To help alleviate this we are developing a wearable system [1, 19] that is capable of detecting and recognizing signs in natural scenes. The system is composed of two main components, sign detection and recognition. The sign detector, uses a conditional maximum entropy model to find regions in an image that correspond to a sign. The sign recognizer matches the hypothesized sign regions with sign images in a database. …


A Study Of Chlorophenol Concentrations In Kentucky Lake, Barrett Brown Dec 2004

A Study Of Chlorophenol Concentrations In Kentucky Lake, Barrett Brown

Bommanna Loganathan

Widespread use of chlorophenols in industry, agricultural and consumer products has resulted in environmental contamination. Exposure to chlorophenols can cause harmful effects in plants and animals, including humans. In this study, sediment, mussel tissues and wood samples from two local reservoirs (Kentucky Lake and Lake Barkley) were analyzed for dichlorophenol (DCP), trichlorophenol (TCP), tetrachlorophenol (TeCP), and pentachlorophenol (PCP). PCP concentrations ranged from below detection limits (0.6 ng) to 86 ng/g dry weight in sediment samples and from 660 to 2270 ng/g dry weight in freshwater mussel tissue samples. Elevated concentrations in mussel tissues indicate bioaccumulation of chlorophenols in freshwater mussels. …


Inverting For Slip On Three-Dimensional Fault Surfaces Using Angular Dislocations, Phillip G. Resor, David Pollard, Frantz Maerten, Laurent Maerten Dec 2004

Inverting For Slip On Three-Dimensional Fault Surfaces Using Angular Dislocations, Phillip G. Resor, David Pollard, Frantz Maerten, Laurent Maerten

Phillip G Resor

The increasing quality of geodetic data (synthetic aperture radar interferometry [INSAR] dense Global Positioning System [GPS] arrays) now available to geophysicists and geologists are not fully exploited in slip-inversion procedures. Most common methods of inversion use rectangular dislocation segments to model fault ruptures and therefore oversimplify fault geometries. These geometric simplifications can lead to inconsistencies when inverting for slip on earthquake faults, and they preclude a more complete understanding of the role of fault geometry in the earthquake process. We have developed a new three-dimensional slip-inversion method based on the analytical solution for an angular dislocation in a linear-elastic, homogeneous, …


Hartford Basin Cross Section – Southington To Portland, Ct, Phillip G. Resor, J Z. Deboer Dec 2004

Hartford Basin Cross Section – Southington To Portland, Ct, Phillip G. Resor, J Z. Deboer

Phillip G Resor

No abstract provided.


Laramie Peak Shear System, Central Laramie Mountains, Wyoming, Usa: Regeneration Of The Archean Wyoming Province During Palaeoproterozoic Accretion, Phillip G. Resor, Arthur W. Snoke Dec 2004

Laramie Peak Shear System, Central Laramie Mountains, Wyoming, Usa: Regeneration Of The Archean Wyoming Province During Palaeoproterozoic Accretion, Phillip G. Resor, Arthur W. Snoke

Phillip G Resor

The Laramie Peak shear system (LPSS) is a 10 km-thick zone of heterogeneous general shear (non-coaxial) that records significant tectonic regeneration of middle-lower crustal rocks of the Archean Wyoming province. The shear system is related to the 1.78–1.74 Ga Medicine Bow orogeny that involved the collision of an oceanic-arc terrane (Colorado province or Green Mountain block or arc) with the rifted, southern margin of the Wyoming province. The style and character of deformation associated with the LPSS is distinctive: a strong, penetrative (mylonitic) foliation commonly containing a moderately steep, SW-plunging elongation lineation. In mylonitic quartzo-feldspathic gneisses of the Fletcher Park …


Western End Of The Honey Hill Fault Along The Eastern Bank Of The Connecticut River, Phillip G. Resor, J Z. Deboer Dec 2004

Western End Of The Honey Hill Fault Along The Eastern Bank Of The Connecticut River, Phillip G. Resor, J Z. Deboer

Phillip G Resor

No abstract provided.


The Framing Effect And Risky Decisions: Examining Cognitive Functions With Fmri, Cleotilde Gonzalez, Jason Dana, Hideya Koshino, Marcel Adam Just Dec 2004

The Framing Effect And Risky Decisions: Examining Cognitive Functions With Fmri, Cleotilde Gonzalez, Jason Dana, Hideya Koshino, Marcel Adam Just

Marcel Adam Just

No abstract provided.


Interactions Between Xenon And Phospholipid Bicelles Studied By 2h/129xe/131xe Nmr And Optical Pumping Of Nuclear Spins, Xiaoxia Li, Caitlin Newberry, Indrajit Saha, Panayiotis Nikolaou, Nicholas Whiting, Boyd M. Goodson Dec 2004

Interactions Between Xenon And Phospholipid Bicelles Studied By 2h/129xe/131xe Nmr And Optical Pumping Of Nuclear Spins, Xiaoxia Li, Caitlin Newberry, Indrajit Saha, Panayiotis Nikolaou, Nicholas Whiting, Boyd M. Goodson

Nicholas Whiting

The interactions between xenon and DMPC/DHPC bicelles (q = 3.5%,7.5% w/v) were studied via 2H, 129Xe, 131Xe, and optically enhanced 129Xe NMR. The chemical shifts, linewidths, and quadrupolar couplings of the xenon/bicelle NMR signals were correlated with different regions of the bicellar phase diagram. The addition of xenon (<70 mM) was observed to reduce the temperature-onset of bicelle alignment by several degrees, in quantitative agreement with effects previously observed with chloroform; however, the stable liquid-crystalline range was not significantly reduced. Preliminary laser-polarized xenon/bicelle studies yielded 129Xe T1 values of ~120 s, long enough to permit a variety of planned experiments.


Distance Learning And Student Satisfaction In Java Programming Courses, Amber Settle, Chad Settle Dec 2004

Distance Learning And Student Satisfaction In Java Programming Courses, Amber Settle, Chad Settle

Amber Settle

Student satisfaction with distance learning is impacted by a variety of factors, including interaction with the instructor and the structure of the course. In an earlier article, we determined that student satisfaction as measured by course evaluation scores in an online discrete mathematics course taught by the first author was not statistically significantly different from that of students in traditional versions of the same course. In this article we show that vastly different results are seen when the course evaluations for online and traditional sections of Java I and II programming courses are considered.


Course Mentoring: Toward Achieving Consistency In The Curriculum, Lucia Dettori, Amber Settle Dec 2004

Course Mentoring: Toward Achieving Consistency In The Curriculum, Lucia Dettori, Amber Settle

Amber Settle

One the main challenges in achieving consistency in the curriculum is the delivery and coordination of multi-section introductory courses. The mix of adjunct, new, and seasoned instructors, the frequent changes in course content and learning goals, and the non-homogeneous student body are some of the factors that makes successfully teaching such courses a challenge. In this paper we describe how the course mentoring project combines personal involvement with a technological solution to build an effective knowledge-sharing virtual community. Course mentoring has proven to be an efficient way to address and overcome the challenges of teaching introductory computer science courses.


Barotropic Tides In The South Atlantic Bight, Brian O. Blanton, Francisco E. Werner, Harvey E. Seim, Richard A. Luettich Jr., Daniel R. Lynch, Keston W. Smith, George Voulgaris, Frederick M. Bingham, Francis Way Dec 2004

Barotropic Tides In The South Atlantic Bight, Brian O. Blanton, Francisco E. Werner, Harvey E. Seim, Richard A. Luettich Jr., Daniel R. Lynch, Keston W. Smith, George Voulgaris, Frederick M. Bingham, Francis Way

George Voulgaris

The characteristics of the principal barotropic diurnal and semidiurnal tides are examined for the South Atlantic Bight (SAB) of the eastern United States coast. We combine recent observations from pressure gauges and ADCPs on fixed platforms and additional short-term deployments off the Georgia and South Carolina coasts together with National Ocean Service coastal tidal elevation harmonics. These data have shed light on the regional tidal propagation, particularly off the Georgia/South Carolina coast, which is perforated by a dense estuary/tidal inlet complex (ETIC). We have computed tidal solutions for the western North Atlantic Ocean on two model domains. One includes a …


Data Exploration Tools For The Gene Ontology Database, Elizabeth Shoop, Paulo Casaes, Getiria Onsongo, Lisa Lesnett, Erla Petursdottir, Edward Donkor, Dennis Tkach, Michael Cosimini Dec 2004

Data Exploration Tools For The Gene Ontology Database, Elizabeth Shoop, Paulo Casaes, Getiria Onsongo, Lisa Lesnett, Erla Petursdottir, Edward Donkor, Dennis Tkach, Michael Cosimini

Elizabeth Shoop

No abstract provided.


Application Of Detuned Laser Beatwave For Generation Of Few-Cycle Electromagnetic Pulses, Serguei Y. Kalmykov, Gennady Shvets Nov 2004

Application Of Detuned Laser Beatwave For Generation Of Few-Cycle Electromagnetic Pulses, Serguei Y. Kalmykov, Gennady Shvets

Serge Youri Kalmykov

An approach to compressing high-power laser beams in plasmas via coherent Raman sideband generation is described. The technique requires two beams: a pump and a probe detuned by a near-resonant frequency \Omega < \omega_p. The two laser beams drive a high-amplitude electron plasma wave (EPW) which modifies the refractive index of plasma so as to produce a periodic phase modulation of the incident laser with the laser beat period t_b = 2\pi / \Omega. After propagation through plasma, the original laser beam breaks into a train of chirped beatnotes (each of duration t_b). The chirp is positive (the longer-wavelength sidebands are advanced in time) when \Omega < \omega_p and negative otherwise. Finite group velocity dispersion (GVD) of radiation in plasma can compress the positively chirped beatnotes to a few-laser-cycle duration thus creating in plasma a sequence of sharp electromagnetic spikes separated in time by t_b. Driven EPW strongly couples the laser sidebands and thus reduces the effect of GVD. Compression of the chirped beatnotes can be implemented in a separate plasma of higher density, where the laser sidebands become uncoupled.


Inheritance Evaluation System Using Islamic Law, Dr. Muhammad Zubair Asghar, Fazal Masud Kundi, Abdur Rashid Khan Nov 2004

Inheritance Evaluation System Using Islamic Law, Dr. Muhammad Zubair Asghar, Fazal Masud Kundi, Abdur Rashid Khan

Dr. Muhammad Zubair Asghar

The research work about the Inheritance Evaluation System using Islamic law is valuable for automatic calculation of share out of total inheritance of a deceased to his/her legal heir(s). First version of the software named as Islamic Inheritance Evaluation System (IIES) deals with Hanfi School of thought. IIES may solve the heritage problem of heirs in text as well as in graphical form at home without establishing a suit in any court. This also leads to further research of who is how much related to whom?


Micro-Bathymetric Mapping Using Acoustic Range Images, Christopher Roman, Hanumant Singh Oct 2004

Micro-Bathymetric Mapping Using Acoustic Range Images, Christopher Roman, Hanumant Singh

Christopher N. Roman

This work focuses on the creation of high resolution micro-bathymetric maps using a high frequency pencil beam sonar. These maps typically cover areas of 10's to 100's of square meters. Data is collected using a sonar mounted to an underwater vehicle that can be positioned at discrete locations on the sea floor or flown in a survey pattern above the bottom. Specifically, we are focused on improving the accuracy of these terrain maps by merging sonar pings taken from multiple vantage points over the same location. This requires the adaption of data registration techniques to handle errors related to the …


Modeling Correlated Main-Chain Motions In Proteins For Flexible Molecular Recognition., Maria Zavodsky, Ming Lei, M. Thorpe, Anthony Day, Leslie Kuhn Oct 2004

Modeling Correlated Main-Chain Motions In Proteins For Flexible Molecular Recognition., Maria Zavodsky, Ming Lei, M. Thorpe, Anthony Day, Leslie Kuhn

Anthony Roy Day

We describe a new method for modeling protein and ligand main-chain flexibility, and show its ability to model flexible molecular recognition. The goal is to sample the full conformational space, including large-scale motions that typically cannot be reached in molecular dynamics simulations due to the computational intensity, as well as conformations that have not been observed yet by crystallography or NMR. A secondary goal is to assess the degree of flexibility consistent with protein–ligand recognition. Flexibility analysis of the target protein is performed using the graph-theoretic algorithm FIRST, which also identifies coupled networks of covalent and noncovalent bonds within the …


An Approach To Facilitate Reliability Testing Of Web Services Components, Jia Zhang Oct 2004

An Approach To Facilitate Reliability Testing Of Web Services Components, Jia Zhang

Jia Zhang

No abstract provided.


Modelling The Turbulent Mixing Noise Associated With Coanda Jets, Caroline Lubert Oct 2004

Modelling The Turbulent Mixing Noise Associated With Coanda Jets, Caroline Lubert

Caroline P Lubert

No abstract provided.