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2008

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Articles 571 - 600 of 5871

Full-Text Articles in Physical Sciences and Mathematics

What Is Ccs?, University Of North Dakota. Energy And Environmental Research Center Nov 2008

What Is Ccs?, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet about carbon capture and storage (CCS) and the Plains CO2 Reduction (PCOR) Partnership. Outlines the three phases of U.S. Department of Energy National Energy Technology Laboratory’s Regional Carbon Sequestration Partnership program. [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]


A Catalog Of Outer Ejecta Knots In The Cassiopeia A Supernova Remnant, Molly C. Hammell, Robert A. Fesen Nov 2008

A Catalog Of Outer Ejecta Knots In The Cassiopeia A Supernova Remnant, Molly C. Hammell, Robert A. Fesen

Dartmouth Scholarship

Hubble Space Telescope images of the core-collapse supernova remnant Cassiopeia A are used to identify high-velocity knots of ejecta located outside the remnant's main emission shell of expanding debris. These ejecta fragments are found near or ahead of the remnant's forward shock front and mostly lie from 120'' to 300'' in radial distance from the remnant's center of expansion. Filter flux ratios when correlated with published spectra show that these knots can be divided into three emission classes: (1) knots dominated by [N II] λλ6548, 6583 emissions, (2) knots dominated by [O II] λλ7319, 7330 emissions, and (3) …


Structure Property Relationships In Organic Conjugated Systems, Luke O'Neill Nov 2008

Structure Property Relationships In Organic Conjugated Systems, Luke O'Neill

Doctoral

A series of pi(п) conjugated oligomers containing 1 to 6 monomer units were studied by absorption and photoluminescence spectroscopies. The results are discussed and examined with regard to the variation of the optical properties with the increase of effective conjugation length. It was found that there was a linear relationship between the positioning of the absorption and photoluminescence maxima plotted against inverse conjugation length. The relationships are in good agreement with the simple particle in a box method, one of the earliest descriptions of the properties of one-dimensional organic molecules. Variations in the infinite chain limit band gap for a …


Virtual World Affordances: Enhancing Brand Value, S. Park, Fiona Fui-Hoon Nah, D. Dewester, B. Eschenbrenner, S. Jeon Nov 2008

Virtual World Affordances: Enhancing Brand Value, S. Park, Fiona Fui-Hoon Nah, D. Dewester, B. Eschenbrenner, S. Jeon

Research Collection School Of Computing and Information Systems

Virtual worlds are three-dimensional, computer-generated worlds that are a natural extension of the existing Internet. Although many businesses are jumping on the bandwagon to maintain a presence in virtual worlds, there is no well-established knowledge or theory to guide businesses in their involvement in these environments. In this paper, we identify affordances in the virtual worlds that can be used to increase the state of flow experienced in a business virtual site, which in turn may enhance brand equity, or the perceived added value of a brand to customers. We present a conceptual model that can be used to guide …


Secure Communications Over Hybrid Military Networks, Vamsi Paruchuri, Arjan Durresi, Sriram Chellappan Nov 2008

Secure Communications Over Hybrid Military Networks, Vamsi Paruchuri, Arjan Durresi, Sriram Chellappan

Computer Science Faculty Research & Creative Works

Stealthiness can be described as a disposition to be sly and to do things surreptitiously. This paper presents a new architecture for flexible and secure networking in battlefields that enables stealthy and covert communication in the presence of node mobility. Our architecture is based on the combination of optical (fiber) and wireless links. Our objective is to be able to carry on undeterred communication without the attack/eavesdropping nodes being able to detect the presence of any communication. This objective is not only crucial for successful completion of the operation, but also for the safety of our mobile nodes, by not …


Localizing Sensor Networks In Un-Friendly Environments, Sriram Chellappan, Vamsi Paruchuri, Dylan Mcdonald, Arjan Durresi Nov 2008

Localizing Sensor Networks In Un-Friendly Environments, Sriram Chellappan, Vamsi Paruchuri, Dylan Mcdonald, Arjan Durresi

Computer Science Faculty Research & Creative Works

In this paper, we study the issue of defending against a wireless sensor network (WSN) that has been deployed by a malicious enemy agent in an area of interest to us. While there can be many approaches to defend against maliciously deployed WSNs, we propose the design of a localization centric approach. Specifically, the problem we address is: given an enemy deployed WSN in an area of interest to us, how can we determine locations of the sensors without co-operating with the sensors themselves during localization. In our approach, we employ a physically mobile agent called the localizer (e.g., a …


Seasonal Changes In A Eutrophic Lake, Wilgreen Lake, Madison County, Kentucky, Richard D. Stockwell, Walter S. Borowski Nov 2008

Seasonal Changes In A Eutrophic Lake, Wilgreen Lake, Madison County, Kentucky, Richard D. Stockwell, Walter S. Borowski

EKU Faculty and Staff Scholarship

WilgreenLake (Madison County, Kentucky) covers ~169 acres, formed in 1966 by damming Taylor Fork. The Wilgreen watershed drains residential developments, modified woodlands, cattle pasture, and some industrial/urban areas in the city of Richmond. The lake is deemed “nutrient impaired” by the EPA.

Our main objective is to document the seasonal changes in key lake parameters from summer stratification through fall overturn over 4 months of sampling, August through November, 2008. We collect temperature, oxygen, pH, and conductivity data from 19 stations at depth intervals of 1 meter using an YSI multi-probe. Concurrent with collecting these framework data, we take water …


Observations Of Clustering Inside Oceanic Bubble Clouds And The Effect On Short-Range Acoustic Propagation, Thomas C. Weber Nov 2008

Observations Of Clustering Inside Oceanic Bubble Clouds And The Effect On Short-Range Acoustic Propagation, Thomas C. Weber

Center for Coastal and Ocean Mapping

It has recently been shown [Weber, T. C. et al. (Year: 2007). “Acoustic propagation through clustered bubble clouds,” IEEE J. Ocean. Eng.32, 513–523] that gas bubble clustering plays a role in determining the acoustic field characteristics of bubbly fluids. In particular, it has been shown that clustering changes the bubble-induced attenuation as well as the ping-to-ping variability in the acoustic field. The degree to which bubble clustering exists in nature, however, is unknown. This paper describes a method for quantifying bubble clustering using a high frequency (400kHz) multibeam sonar, and reports on observations of near-surface bubbleclustering during a storm ( …


Kinetic And Spectroscopic Analysis Of The Catalytic Role Of H79 In The Methionine Aminopeptidase From Escherichia Coli, Sarah J. Watterson, Sanghamitra Mitra, Sabina I. Swierczek, Brian Bennett, Richard C. Holz Nov 2008

Kinetic And Spectroscopic Analysis Of The Catalytic Role Of H79 In The Methionine Aminopeptidase From Escherichia Coli, Sarah J. Watterson, Sanghamitra Mitra, Sabina I. Swierczek, Brian Bennett, Richard C. Holz

Physics Faculty Research and Publications

To gain insight into the role of the strictly conserved histidine residue, H79, in the reaction mechanism of the methionyl aminopeptidase from Escherichia coli (EcMetAP-I), the H79A mutated enzyme was prepared. Co(II)-loaded H79A exhibits an overall >7000-fold decrease in specific activity. The almost complete loss of activity is primarily due to a >6000-fold decrease in kcat. Interestingly, the Km value obtained for Co(II)-loaded H79A was approximately half the value observed for wild-type (WT) EcMetAP-I. Consequently, kcat/Km values decreased only 3000-fold. On the other hand, the observed specific activity of Mn(II)-loaded …


Defining Resonance Raman Spectral Responses To Substrate Binding By Cytochrome P450 From Pseudomonas Putida, Piotr J. Mak, Daniel Kaluka, Munyaradzi Edith Manyumwa, Haiqing Zhang, Tianjing Deng, James R. Kincaid Nov 2008

Defining Resonance Raman Spectral Responses To Substrate Binding By Cytochrome P450 From Pseudomonas Putida, Piotr J. Mak, Daniel Kaluka, Munyaradzi Edith Manyumwa, Haiqing Zhang, Tianjing Deng, James R. Kincaid

Chemistry Faculty Research and Publications

Resonance Raman spectra are reported for substrate-free and camphor-bound cytochrome P450cam and its isotopically labeled analogues that have been reconstituted with protoheme derivatives that bear -CD3 groups at the 1, 3, 5, and 8-positions (d12-protoheme) or deuterated methine carbons (d4-protoheme). In agreement with previous studies of this and similar enzymes, substrate binding induces changes in the high frequency and low frequency spectral regions, with the most dramatic effect in the low frequency region being activation of a new mode near 367 cm−1. This substrate-activated mode had been previously assigned as a second “propionate bending” mode (Chen et …


Water, Energy And Climate Change Nexus For Egypt, Adel Beshara Nov 2008

Water, Energy And Climate Change Nexus For Egypt, Adel Beshara

Egypt & Libya

Evaluating Egypt’s future energy needs for water production and mobilisation and water needs for energy production until 2050, while taking into consideration the “climate change” factor. Identifying the existing gaps in related data and information that is hindering the adequate evaluation of present and future water and energy needs. Estimate required investments to supply energy and water needs until 2050 (without and with taking the impacts of climate change into account). Starting the establishment of a “knowledge platform” on this issue in the SEMCs to initiate information, experience and awareness sharing. Drawing the attention to and developing a roadmap for …


Modality Mixture Projections For Semantic Video Event Detection, Jialie Shen, Dacheng Tao, Xuelong Li Nov 2008

Modality Mixture Projections For Semantic Video Event Detection, Jialie Shen, Dacheng Tao, Xuelong Li

Research Collection School Of Computing and Information Systems

Event detection is one of the most fundamental components for various kinds of domain applications of video information system. In recent years, it has gained a considerable interest of practitioners and academics from different areas. While detecting video event has been the subject of extensive research efforts recently, much less existing approach has considered multimodal information and related efficiency issues. In this paper, we use a subspace selection technique to achieve fast and accurate video event detection using a subspace selection technique. The approach is capable of discriminating different classes and preserving the intramodal geometry of samples within an identical …


Visualizing A Fourth Dimension: Hypercubic Resistor Networks, Andrew J. Nelson '08 Nov 2008

Visualizing A Fourth Dimension: Hypercubic Resistor Networks, Andrew J. Nelson '08

Honors Projects

A booming field in physics research today is the search for extra dimensions. This is something that has been thought about and discussed in both the scientific and non-scientific world for a long time. Many physicists are currently attempting to answer the question: "is our world really four dimensional?" The purpose of this research, however, is not to answer that question. The purpose of this work is to help reveal four-dimensional artifacts in our perceived three-dimensional world in order to help a student, even a non-physicist, to understand and visualize how the extra spatial dimensionality, if present, might reveal itself …


Dynamical Pattern Formation During Growth Of A Dual-Species Bose-Einstein Condensate, Shai Ronen, John L. Bohn, Laura Elisa Halmo, Mark Edwards Nov 2008

Dynamical Pattern Formation During Growth Of A Dual-Species Bose-Einstein Condensate, Shai Ronen, John L. Bohn, Laura Elisa Halmo, Mark Edwards

Physics & Astronomy: Faculty Publications

We simulate the growth of a dual species Bose-Einstein condensate using a Gross-Pitaevskii equation with an additional gain term giving rise to the growth. Such growth occurs during simultaneous evaporative cooling of a mixture of two gases. The ground state of a dual condensate is normally either a miscible mixture, or an immiscible phase with two spatially separated components. In a cigar trap the ground state typically consists of one component in the center, and the other component flanking it. Our simulations show that when the condensates are formed in a cigar trap and the mixture is phase separated, then …


Revisiting Unitarity Corrections For Electromagnetic Processes In Collisions Of Relativistic Nuclei, Ulrich D. Jentschura, Kai Hencken, Valery G. Serbo Nov 2008

Revisiting Unitarity Corrections For Electromagnetic Processes In Collisions Of Relativistic Nuclei, Ulrich D. Jentschura, Kai Hencken, Valery G. Serbo

Physics Faculty Research & Creative Works

Unitarity corrections to several electromagnetic processes in collisions of relativistic heavy nuclei are considered. They are due to the unitarity requirement for the S-matrix and correspond to the exchange of a light-by-light scattering block between colliding nuclei. We obtain improved results for the corrections to e+ e- and μ+ μ- pair production as well as new results for unitarity corrections to the production of photons via virtual Compton and virtual Delbrück scattering. These corrections can be numerically large; e.g., the μ+ μ- pair production cross section is reduced by about 50% and nuclear bremsstrahlung …


New (E,2e) Studies Of Atomic And Molecular Targets, E. M. Staicu-Casagrande, A. Naja, A. Lahmam-Bennani, A. S. Kheifets, Don H. Madison, B. Joulakian Nov 2008

New (E,2e) Studies Of Atomic And Molecular Targets, E. M. Staicu-Casagrande, A. Naja, A. Lahmam-Bennani, A. S. Kheifets, Don H. Madison, B. Joulakian

Physics Faculty Research & Creative Works

We report new coplanar (e,2e) measurements characterised by large energy transfer and close to minimum momentum transfer from the projectile to the target. Ionisation of the two-electron targets He and H2 is investigated under these particular kinematics. The experimental data are compared with the predictions of the most elaborate theoretical models. The obtained good agreement motivated us to extend our research to the case of more complex targets such as Ar. Comparison with the most elaborate models in the case of multi-electron targets is excellent. Destructive and constructive interference effects in the case of H2 are observed and …


A New Framework For The Design And Analysis Of Identity-Based Identification Schemes, Guomin Yang, Jing Chen, Duncan S. Wong, Xiaotie Deng, Dongsheng Wang Nov 2008

A New Framework For The Design And Analysis Of Identity-Based Identification Schemes, Guomin Yang, Jing Chen, Duncan S. Wong, Xiaotie Deng, Dongsheng Wang

Research Collection School Of Computing and Information Systems

Constructing an identification scheme is one of the fundamental problems in cryptography, and is very useful in practice. An identity-based identification (IBI) scheme allows a prover to identify himself to a public verifier who knows only the claimed identity of the prover and some public information. In this paper, we propose a new framework for both the design and analysis of IBI schemes. Our approach works in an engineering way. We first identify an IBI scheme as the composition of two building blocks, and then show that, with different security properties of these building blocks, the corresponding IBI schemes can …


Lifestyle Of Shellmound Builders In Brazil (Galley Proofs), Sabine Eggers, C. C. Petronilho, K. Brandt, J. Filippini, Karl J. Reinhard Nov 2008

Lifestyle Of Shellmound Builders In Brazil (Galley Proofs), Sabine Eggers, C. C. Petronilho, K. Brandt, J. Filippini, Karl J. Reinhard

School of Natural Resources: Faculty Publications

The contact of inland and coastal prehistoric groups in Brazil is believed to have been restricted to regions with no geographical barrier, as is the case in the Ribeira de Iguape valley. The inland osteological collection from the riverine shellmound Moraes (5800–4500 BP) represents a unique opportunity to test this assumption for this region. Despite cultural similarities between riverine and coastal shellmounds, important ecological and site distribution differences are expected to impact on lifestyle. The purpose of this study is thus to document and interpret health and lifestyle indicators in Moraes in comparison to coastal shellmound groups. Specifically we test …


Analyzing The Catalytic Mechanism Of The Fe-Type Nitrile Hydratase From Comamonas Testosteroni Ni1, Saroja Rao, Richard C. Holz Nov 2008

Analyzing The Catalytic Mechanism Of The Fe-Type Nitrile Hydratase From Comamonas Testosteroni Ni1, Saroja Rao, Richard C. Holz

Chemistry Faculty Research and Publications

In order to gain insight into the catalytic mechanism of Fe-type nitrile hydratases (NHase), the pH and temperature dependence of the kinetic parameters kcat, Km, and kcat/Km along with the solvent isotope effect were examined for the Fe-type NHase from Comamonas testosteroni Ni1 (CtNHase). CtNHase was found to exhibit a bell-shaped curve for plots of relative activity vs pH over pH values 4−10 for the hydration of acrylonitrile and was found to display maximal activity at pH ∼7.2. Fits of these data provided a pKES1 value of …


Regulating Self-Organizing Nanostructures Via External Mechanism, Jiangyu Li, Q. G. Du, Stephen Ducharme Nov 2008

Regulating Self-Organizing Nanostructures Via External Mechanism, Jiangyu Li, Q. G. Du, Stephen Ducharme

Stephen Ducharme Publications

Self-organizing nanostructures are ubiquitous in both natural and synthetic materials. They are not only appealing scientifically, by revealing the intrinsic atomic and molecular interactions that might be difficult to detect otherwise, but may also hold the key for the development of novel functional structures and devices. For their technological potential to be fully realized, the size, morphology, and distribution of the self-organizing nanostructures must be regulated. In this paper, we investigate the principles under which the self-organizing nanostructures can be regulated via external mechanisms. Using nanomesa and nanowell formation in polyvinylidene fluoride trifluoroethylene copolymer film as an example, we demonstrate …


Progress Toward Meeting The Challenges Of Our Coastal Urban Future, Juile Pullen, Jason Ching, David J. Sailor, William Thompson, Bob Bornstein, Darko Koracin Nov 2008

Progress Toward Meeting The Challenges Of Our Coastal Urban Future, Juile Pullen, Jason Ching, David J. Sailor, William Thompson, Bob Bornstein, Darko Koracin

Mechanical and Materials Engineering Faculty Publications and Presentations

The article provides information on the Seventh Conference on Coastal Atmospheric and Oceanic Prediction and Processes, and the Seventh Symposium on the Urban Environment in San Diego, California on September 9-13, 2008. Topics include the heterogeneity of urban areas, coastal vulnerabilities, urban planning, and emergency response modeling. The conference featured several speakers including Walter Dabberdt and James Voogt.


Bias And Controversy In Evaluation Systems, Hady Wirawan Lauw, Ee Peng Lim, Ke Wang Nov 2008

Bias And Controversy In Evaluation Systems, Hady Wirawan Lauw, Ee Peng Lim, Ke Wang

Research Collection School Of Computing and Information Systems

Evaluation is prevalent in real life. With the advent of Web 2.0, online evaluation has become an important feature in many applications that involve information (e.g., video, photo, and audio) sharing and social networking (e.g., blogging). In these evaluation settings, a set of reviewers assign scores to a set of objects. As part of the evaluation analysis, we want to obtain fair reviews for all the given objects. However, the reality is that reviewers may deviate in their scores assigned to the same object, due to the potential bias of reviewers or controversy of objects. The statistical approach of averaging …


Profile-Guided Program Simplification For Effective Testing And Analysis, Lingxiao Jiang, Zhendong Su Nov 2008

Profile-Guided Program Simplification For Effective Testing And Analysis, Lingxiao Jiang, Zhendong Su

Research Collection School Of Computing and Information Systems

Many testing and analysis techniques have been developed for inhouse use. Although they are effective at discovering defects before a program is deployed, these techniques are often limited due to the complexity of real-world code and thus miss program faults. It will be the users of the program who eventually experience failures caused by the undetected faults. To take advantage of the large number of program runs carried by the users, recent work has proposed techniques to collect execution profiles from the users for developers to perform post-deployment failure analysis. However, in order to protect users' privacy and to reduce …


Lsuhsc Facilities Biweekly Update: November 2008, Lsuhsc Property And Facilities Management Nov 2008

Lsuhsc Facilities Biweekly Update: November 2008, Lsuhsc Property And Facilities Management

LSUHSC Facilities Biweekly Updates: 2008

LSUHSC Facilities Biweekly Updates from November 7 and 21, 2008.

These updates describe damage and a timeline of repairs at the LSU Health Sciences Center - New Orleans campus due to Hurricane Katrina which made landfall August 29, 2005.


Lsuhsc Facilities Daily Update: November 2008, Lsuhsc Property And Facilities Management Nov 2008

Lsuhsc Facilities Daily Update: November 2008, Lsuhsc Property And Facilities Management

LSUHSC Facilities Daily Updates: 2008

LSUHSC Dailly Facilities Updates from November 2008. These updates describe damage and a timeline of repairs at the LSU Health Sciences Center - New Orleans campus due to Hurricane Katrina which made landfall August 29, 2005.


Beyond Semantic Search: What You Observe May Not Be What You Think, Chong-Wah Ngo, Yu-Gang Jiang, Xiaoyong Wei, Wanlei Zhao, Feng Wang, Xiao Wu, Hung-Khoon Tan Nov 2008

Beyond Semantic Search: What You Observe May Not Be What You Think, Chong-Wah Ngo, Yu-Gang Jiang, Xiaoyong Wei, Wanlei Zhao, Feng Wang, Xiao Wu, Hung-Khoon Tan

Research Collection School Of Computing and Information Systems

This paper presents our approaches and results of the four TRECVID 2008 tasks we participated in: high-level feature extraction, automatic video search, video copy detection, and rushes summarization


A Neural Network Model For A Hierarchical Spatio-Temporal Memory, Kiruthika Ramanathan, Luping Shi, Jianming Li, Kian Guan Lim, Zhi Ping Ang, Chong Chong Tow Nov 2008

A Neural Network Model For A Hierarchical Spatio-Temporal Memory, Kiruthika Ramanathan, Luping Shi, Jianming Li, Kian Guan Lim, Zhi Ping Ang, Chong Chong Tow

Research Collection School Of Computing and Information Systems

The architecture of the human cortex is uniform and hierarchical in nature. In this paper, we build upon works on hierarchical classification systems that model the cortex to develop a neural network representation for a hierarchical spatio-temporal memory (HST-M) system. The system implements spatial and temporal processing using neural network architectures. We have tested the algorithms developed against both the MLP and the Hierarchical Temporal Memory algorithms. Our results show definite improvement over MLP and are comparable to the performance of HTM.


Model-Driven Remote Attestation: Attesting Remote System From Behavioral Aspect, Liang Gu, Xuhua Ding, Robert H. Deng, Yanzhen Zou, Bing Xie, Weizhong Shao, Hong Mei Nov 2008

Model-Driven Remote Attestation: Attesting Remote System From Behavioral Aspect, Liang Gu, Xuhua Ding, Robert H. Deng, Yanzhen Zou, Bing Xie, Weizhong Shao, Hong Mei

Research Collection School Of Computing and Information Systems

Remote attestation was introduced in TCG specifications to determine whether a remote system is trusted to behave in a particular manner for a specific purpose; however, most of the existing approaches attest only the integrity state of a remote system and hence have a long way to go in achieving the above attestation objective. Behavior-based attestation and semantic attestation were recently introduced as solutions to approach the TCG attestation objective. In this paper, we extend behavior-based attestation to a model-driven remote attestation to prove that a remote system is trusted as defined by TCG. Our model-driven remote attestation verifies two …


Irrelevance, Polymorphism, And Erasure In Type Theory, Richard Nathan Mishra-Linger Nov 2008

Irrelevance, Polymorphism, And Erasure In Type Theory, Richard Nathan Mishra-Linger

Dissertations and Theses

Dependent type theory is a proven technology for verified functional programming in which programs and their correctness proofs may be developed using the same rules in a single formal system. In practice, large portions of programs developed in this way have no computational relevance to the ultimate result of the program and should therefore be removed prior to program execution. In previous work on identifying and removing irrelevant portions of programs, computational irrelevance is usually treated as an intrinsic property of program expressions. We find that such an approach forces programmers to maintain two copies of commonly used datatypes: a …


Search For Gravitational-Wave Bursts From Soft Gamma Repeaters, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, K. Hayama, Soma Mukherjee, Soumya Mohanty, Joseph D. Romano, Robert Stone Nov 2008

Search For Gravitational-Wave Bursts From Soft Gamma Repeaters, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, K. Hayama, Soma Mukherjee, Soumya Mohanty, Joseph D. Romano, Robert Stone

Physics & Astronomy Faculty Publications

We present a LIGO search for short-duration gravitational waves (GWs) associated with soft gamma ray repeater (SGR) bursts. This is the first search sensitive to neutron star f modes, usually considered the most efficient GW emitting modes. We find no evidence of GWs associated with any SGR burst in a sample consisting of the 27 Dec. 2004 giant flare from SGR 1806−20 and 190 lesser events from SGR 1806−20 and SGR 1900+14. The unprecedented sensitivity of the detectors allows us to set the most stringent limits on transient GW amplitudes published to date. We find upper limit estimates on the …