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2007

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Articles 2761 - 2790 of 6758

Full-Text Articles in Physical Sciences and Mathematics

Chemical Stidies On Nucleic Acids Interaction With Some Antiviral Drugs: Developing Of Some New Methods For Nucleic Aeids Determination And Their Application, Islam Kamal Ali Shams May 2007

Chemical Stidies On Nucleic Acids Interaction With Some Antiviral Drugs: Developing Of Some New Methods For Nucleic Aeids Determination And Their Application, Islam Kamal Ali Shams

Theses

No abstract provided.


Modeling Architectural Strategy Using Design Structure Networks, C. Jason Woodard May 2007

Modeling Architectural Strategy Using Design Structure Networks, C. Jason Woodard

Research Collection School Of Computing and Information Systems

System architects face the formidable task of purposefully shaping an evolving space of complex designs. Their task s further complicated when they lack full control of the design process, and therefore must anticipate the behavior of other stakeholders, including the designers of component products and competing systems. This paper presents a conceptual tool called a design structure network (DSN) to help architects and design scientists reason effectively about these situations. A DSN is a graphical representation of a system’s design space. DSNs improve on existing representation schemes by providing a compact and intuitive way to express design options—the ability to …


Achieving End-To-End Authentication In Intermediary-Enabled Multimedia Delivery Systems, Robert H. Deng, Yanjiang Yang May 2007

Achieving End-To-End Authentication In Intermediary-Enabled Multimedia Delivery Systems, Robert H. Deng, Yanjiang Yang

Research Collection School Of Computing and Information Systems

Considerable research and experiment results in recent years have shown that the server-proxy-user architecture represents an efficient and scalable new paradigm for multimedia content delivery. However, not much effort has been spent on the security issues in such systems. In this paper, we study data authentication in multimedia content delivery, and in particular, we focus on achieving end-to-end authentication from the multimedia server to end users in the server-proxy-user architecture where intermediary proxies transcode multimedia content dynamically. We present a formal model for the end-to-end authentication problem, and propose a basic construction for generic data modality and prove its security. …


Salinity, Ph, Temperature, Desiccation And Hypoxia Tolerance In The Invasive Freshwater Apple Snail Pomacea Insularum, Veena Ramakrishnan May 2007

Salinity, Ph, Temperature, Desiccation And Hypoxia Tolerance In The Invasive Freshwater Apple Snail Pomacea Insularum, Veena Ramakrishnan

Earth & Environmental Sciences Dissertations

Pomacea insularum is a tropical and subtropical, ampullariid, freshwater prosobranch snail that is native to slow-flowing rivers and canals in South America. It is a member of the genus, Pomacea, and, like other species in this genus, can be a severe agricultural pest in wetland rice and taro agriculture systems. It has been introduced to the United States, establishing populations in the rice belt region of southeastern Texas. The resistance adaptations of P. insularum were investigated with respect to important physico-chemical parameters including temperature, salinity, pH, emersion, desiccation and progressive hypoxia in order to predict its potential distribution in North …


Why? Why? Why?: Future Teachers Discover Mathematical Depth, Perla Myers Phd May 2007

Why? Why? Why?: Future Teachers Discover Mathematical Depth, Perla Myers Phd

Mathematics: Faculty Scholarship

In mathematics, it is not just the how, the procedures for solving problems, that is important, but the why, the underlying concepts, Perla Myers explains. When teachers regain the childlike wonder that leads them to seek the why of math, they will be better able to help their students learn.


Automated Gene Classification Using Nonnegative Matrix Factorization On Biomedical Literature, Kevin Erich Heinrich May 2007

Automated Gene Classification Using Nonnegative Matrix Factorization On Biomedical Literature, Kevin Erich Heinrich

Doctoral Dissertations

Understanding functional gene relationships is a challenging problem for biological applications. High-throughput technologies such as DNA microarrays have inundated biologists with a wealth of information, however, processing that information remains problematic. To help with this problem, researchers have begun applying text mining techniques to the biological literature. This work extends previous work based on Latent Semantic Indexing (LSI) by examining Nonnegative Matrix Factorization (NMF). Whereas LSI incorporates the singular value decomposition (SVD) to approximate data in a dense, mixed-sign space, NMF produces a parts-based factorization that is directly interpretable. This space can, in theory, be used to augment existing ontologies …


The Effects Of Gaze Guidance On Educational Software, Brian Murphy May 2007

The Effects Of Gaze Guidance On Educational Software, Brian Murphy

All Theses

There are currently three main kinds of eye tracking applications: gaze-responsive, gaze-aware, and gaze-contingent. A fourth classification, termed gaze-guiding, to our knowledge, coined and implemented for the first time. The gaze-guiding technique is the use of motion, light, color, or other visual stimuli to modify the user's fixation to predetermined locations when the user fixates on specific areas of interest. To test the technique, an education software program that teaches physics through the use of gaze-guidance was developed. It is suggested that a natural mapping exists between gaze-guidance and the software's built-in lesson plan. It is also speculated that gaze-guidance …


Arrow Symbols: Theory For Interpretation, Yohei Kurata May 2007

Arrow Symbols: Theory For Interpretation, Yohei Kurata

Electronic Theses and Dissertations

People often sketch diagrams when they communicate successfully among each other. Such an intuitive collaboration would also be possible with computers if the machines understood the meanings of the sketches. Arrow symbols are a frequent ingredient of such sketched diagrams. Due to the arrows’ versatility, however, it remains a challenging problem to make computers distinguish the various semantic roles of arrow symbols. The solution to this problem is highly desirable for more effective and user-friendly pen-based systems. This thesis, therefore, develops an algorithm for deducing the semantic roles of arrow symbols, called the arrow semantic interpreter (ASI). The …


Remote Assessment Of 4-D Phytoplankton Distributions Off The Washington Coast, Brandon S. Sackmann May 2007

Remote Assessment Of 4-D Phytoplankton Distributions Off The Washington Coast, Brandon S. Sackmann

Electronic Theses and Dissertations

Satellite-based optical measurements were coupled with physical and optical measurements from Seaglider – a long-range autonomous glider – to study interactions between biological and physical processes off the coast of Washington, USA, and to evaluate space-time variability of regional phytoplankton and particle distributions. Using satellite ocean color data variability in near-surface chlorophyll a was characterized across a range of spatial and temporal scales ranging from 1 – 500 km and from days – years to assess region-wide responses by phytoplankton to changes in environmental conditions. Results from 1998 – 2002 revealed both strong negative and positive anomalies associated with lingering …


Modification Of Semi-Metal Oxide And Metal Oxide Powders By Atomic Layer Deposition Of Thin Films, Mark Q. Snyder May 2007

Modification Of Semi-Metal Oxide And Metal Oxide Powders By Atomic Layer Deposition Of Thin Films, Mark Q. Snyder

Electronic Theses and Dissertations

This work describes two methods of modifying, and the subsequent characterizing of, oxide nanopowders. The first method, atomic layer deposition, or ALD, is a series of surface-limited reactions that are repeated to deposit a thin, inorganic film on the surface of the nanopowder. Deposition of a thin film is a useful method to alter the surface properties of a material while retaining its bulk properties. Part of this thesis concerns the understanding of the growth mechanism of thin film titanium nitride (a material known for thermal and chemical stability as well as electronic conductivity) on silica through the ALD process. …


Population Viability Analysis Of Monk Parakeets In The United States And Examination Of Alternative Management Strategies, Stephen Pruett-Jones, James R. Newman, Christian M. Newman, Michael L. Avery, James R. Lindsay May 2007

Population Viability Analysis Of Monk Parakeets In The United States And Examination Of Alternative Management Strategies, Stephen Pruett-Jones, James R. Newman, Christian M. Newman, Michael L. Avery, James R. Lindsay

United States Department of Agriculture Wildlife Services: Staff Publications

In the United States, monk parakeets (Myiopsitta monachus) are expanding their geographical distribution, and their overall population size is growing exponentially. Monk parakeets are causing widespread economic damage in the United States by nesting on utility structures, which leads to electrical fires and power outages. Although few life history data are available for the species from North America, extensive data are available from the species’ native range in South America. Incorporating data from South America into the population viability analysis program VORTEX, we simulated population growth in United States monk parakeets to determine whether it is likely that …


Us Department Of Agriculture, Wildlife Services, National Wildlife Research Center, Brian E. Washburn, Thomas W. Seamans May 2007

Us Department Of Agriculture, Wildlife Services, National Wildlife Research Center, Brian E. Washburn, Thomas W. Seamans

United States Department of Agriculture Wildlife Services: Staff Publications

Herbaceous vegetation comprises the main habitat type in cool-seasons grasslands and can be managed by various methods. We compared changes in plant communities and bird and mammal use of grasslands that were not managed, managed by mechanical methods (mowing), or managed by chemical methods (plant growth regulator). This 1-year study was conducted from May through October 2003 in Erie County, Ohio. Twelve circular 1.5 ha plots were established: 4 were not managed, 4 were mowed to maintain vegetation height between 9–15 cm, and 4 were sprayed with a plant growth regulator and mowed when vegetation exceeded 15 cm. We monitored …


Comparison Of 2 Vegetation-Height Management Practices For Wildlife Control At Airports, Thomas W. Seamans, Scott C. Barras, Glen E. Bernhardt, Bradley F. Blackwell, Jonathan D. Cepek May 2007

Comparison Of 2 Vegetation-Height Management Practices For Wildlife Control At Airports, Thomas W. Seamans, Scott C. Barras, Glen E. Bernhardt, Bradley F. Blackwell, Jonathan D. Cepek

United States Department of Agriculture Wildlife Services: Staff Publications

Vegetation-height management is a potential method to reduce bird numbers at airports. Based on studies in Europe, researchers recommended vegetation heights around 25 cm; however, preliminary studies in the United States produced conflicting results regarding the effect of tall (18 to >25 cm) vegetation on bird numbers at airports. From 1999 to 2002, we compared birds and other wildlife use of 4 short-vegetation plots (mean maximum height of 15.6 cm ± 5.1 SE and visual obstruction reading of 4.6 ± 3.0 cm) and 4 tall-vegetation plots (mean maximum height of 26.9 ± 8.4 cm and visual obstruction reading of 10.0 …


Seasonal Variations In Fish Assemblages Of Small Warmwater Streams In Four Southeastern National Parks, Joseph Carl Zimmerman May 2007

Seasonal Variations In Fish Assemblages Of Small Warmwater Streams In Four Southeastern National Parks, Joseph Carl Zimmerman

Masters Theses

Small warm-water streams in the southeastern United States experience significant differences in temperature, as well as changes in physical parameters due to seasonal fluctuations. It has been generally thought that fish assemblage patterns change as a direct result of these seasonal variations. This study was designed to determine the effects of variable flow regimes on fish species composition, diversity, and abundance. Eight small warm-water streams in four national parks (Chickamauga and Chattanooga National Military Park, Fort Donelson National Battlefield, Abraham Lincoln Birthplace National Historic Site, and Russell Cave National Monument) were sampled May-June 2005 for the summer trials, October-November 2005 …


Effects Of Quaternary Climate Change On Tributary Sedimentation And Geomorphology In Eastern Grand Canyon, Benjamin D. Dejong May 2007

Effects Of Quaternary Climate Change On Tributary Sedimentation And Geomorphology In Eastern Grand Canyon, Benjamin D. Dejong

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Climate variability has had a dramatic impact on eastern Grand Canyon tributaries over the past ~100 ky. This is readily observed in the Lava Chuar and Comanche catchments, which host well preserved colluvial remnants and river terraces that resulted from several climate-induced cycles of aggradation and incision. This study investigates these climate responses using surveying, sedimentology, and luminescence geochronology methods to investigate the mechanisms and timing of their deposition.

The survey data demonstrate that the concavity of terrace treads is lower than modern drainages. The sedimentology suggests the prevalence of stream-flow reworking of debris flow deposits and portrays an expected …


The Geologic History Of Subsurface Arkosic Sedimentary Rocks In The San Andreas Fault Observatory At Depth (Safod) Borehole, Central California, Sarah D. Draper May 2007

The Geologic History Of Subsurface Arkosic Sedimentary Rocks In The San Andreas Fault Observatory At Depth (Safod) Borehole, Central California, Sarah D. Draper

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The aim of the San Andreas Fault Observatory at Depth (SAFOD) project, a component of the NSF Earthscope Initiative, is to directly observe active fault processes at seismogenic depths through the drilling of a 3 km deep (true vertical depth) inclined borehole across San Andreas fault. Preliminary subsurface models based on surface mapping and geophysical data predicted different lithologies than were actually encountered. At 1920 meters measured depth (mmd), a sequence of well-indurated, interbedded arkosic conglomerates, sandstones, and siltstones was encountered. We present a detailed lithologic and structural characterization as a step toward understanding the complex geologic history of this …


Structural Characterization Of Three Southeast Segments Of The Clark Fault, Salton Trough California, Benjamin E. Belgarde May 2007

Structural Characterization Of Three Southeast Segments Of The Clark Fault, Salton Trough California, Benjamin E. Belgarde

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We examine the structural complexities of a 28-km long part of the Clark fault of the San Jacinto fault zone in southern California in order to better document its lateral extent and the style of deformation of its southeast end. Changes in structural style are observed as the Clark fault’s damage zone widens from ~ 1-2 km in crystalline rocks of the Peninsular Ranges southeastward to ~ 18 km in the sedimentary rocks of the San Felipe-Borrego subbasin of the Salton Trough. The Clark fault extends into the San Felipe-Borrego subbasin as the Arroyo Salada segment for ~ 11-12 km …


Investigations Of The Mechanism Of Dna Cleavage Using Ruthenium Polypyridyl Complexes, Fiona Ongeri May 2007

Investigations Of The Mechanism Of Dna Cleavage Using Ruthenium Polypyridyl Complexes, Fiona Ongeri

Chemistry & Biochemistry Theses

We have synthesized a ruthenium complex, [(phen)2Ru(tatpp)Ru(phen)2]4+ (P4+), which has been shown to undergo various redox and protonation steps to form different species that can be monitored by UV-Vis spectroscopy. In Chapter 2, the photochemistry of P4+ in the presence and absence of DNA was studied. It was hypothesized that the lifetime (t1/2) of the excited state of P4+, P*, would be extended in the presence of DNA. However, studies conducted showed that the lifetime of P* was diminished in the presence of DNA as compared to P4+ alone. Experiments have also shown that P4+ is capable of damaging DNA …


Tide Aware Enc: Demonstration Of An Operational Concept, Rick T. Brennan, Barry Gallagher, Jack Riley, Schwehr Kurt, Lee Alexander May 2007

Tide Aware Enc: Demonstration Of An Operational Concept, Rick T. Brennan, Barry Gallagher, Jack Riley, Schwehr Kurt, Lee Alexander

Center for Coastal and Ocean Mapping

No abstract provided.


Proposed Ais Binary Message Format Using Xml For Providing Hydrographic-Related Information, Schwehr Kurt, Lee Alexander May 2007

Proposed Ais Binary Message Format Using Xml For Providing Hydrographic-Related Information, Schwehr Kurt, Lee Alexander

Center for Coastal and Ocean Mapping

UNH is working with the USCG and NOAA to use XML (Extensible Markup Language) to define binary messages for maritime-based AIS (Automatic Identification System). A draft specification format is under development that will enable hydrographic and maritime safety agencies to encode AIS message contents by providing a bit-level description in XML (informally known the "AIS Binary Message Decoder Ring"). An AIS binary message definition in XML specifies the order, length, and type of fields following a subset of that used by the ITU-R.M.1371-1. The specification is independent of programming language (e.g., can be implemented in C, C++, C#, Java, Python, …


Google Earth Visualizations: Preview And Delivery Of Hydrographic And Other Marine Datasets, Kurt Schwehr, Briana M. Sullivan, James V. Gardner May 2007

Google Earth Visualizations: Preview And Delivery Of Hydrographic And Other Marine Datasets, Kurt Schwehr, Briana M. Sullivan, James V. Gardner

Center for Coastal and Ocean Mapping

Existing hydrographic data analysis and visualization tools are very powerful, but lack easy access to web data management tools. Virtual globe software provides a gateway to a host of important data products in formats usable by specialized tools such as CARIS, Fledermaus, and Arc/Info. With virtual globe interfaces, users see complimentary and consistent geographic representations of available data in an easy-tonavigate format. We present a preview of visualizations that build upon virtual globe software. These examples are viewed in Google Earth, but could also be implemented in a number of alternative programs (e.g. NASA World Wind, Dapple, OSSIM Planet). We …


Application Of High-Precision Timing Systems To Distributed Survey Systems, Brian R. Calder, Rick T. Brennan, C Malzone, J Marcus, Peter Canter May 2007

Application Of High-Precision Timing Systems To Distributed Survey Systems, Brian R. Calder, Rick T. Brennan, C Malzone, J Marcus, Peter Canter

Center for Coastal and Ocean Mapping

In any hydrographic survey system that consists of more than one computer, one of the most difficult integration problems is to ensure that all components maintain a coherent sense of time. Since virtually all modern survey systems are of this type, timekeeping and synchronized timestamping of data as it is created is of significant concern. This paper describes a method for resolving this problem based on the IEEE 1588 Precise Time Protocol (PTP) implemented by hardware devices, layered with some custom software called the Software Grandmaster (SWGM) algorithm. This combination of hardware and software maintains a coherent sense of time …


Clustering Acoustic Backscatter In The Angular Response Space, Luciano E. Fonseca, Brian R. Calder May 2007

Clustering Acoustic Backscatter In The Angular Response Space, Luciano E. Fonseca, Brian R. Calder

Center for Coastal and Ocean Mapping

Backscatter mosaicking is a necessary step in the analysis and interpretation of sidescan and multibeam sonar records. However, due to limitations intrinsic to the mosaicking technique, backscatter mosaics are restricted in their capacity to unambiguously discriminate seafloor properties. A more adequate technique to characterize the seafloor is the analysis of backscatter angular responses, since those responses are intrinsic properties of the seafloor. This technique sometimes lacks spatial resolution, however, as the analysis is limited to the swath width of the sonar. In this paper, we propose an approach to combine mosaicking and angular response analysis techniques in an attempt to …


Marine Heritage Monitoring With High Resolution Survey Tools: Scapamap 2001-2006, Brian R. Calder, Bobby Forbes, Duncan Mallace May 2007

Marine Heritage Monitoring With High Resolution Survey Tools: Scapamap 2001-2006, Brian R. Calder, Bobby Forbes, Duncan Mallace

Center for Coastal and Ocean Mapping

Archaeologically, marine sites can be just as significant as those on land. Until recently, however, they were not protected in the UK to the same degree, leading to degradation of sites; the difficulty of investigating such sites still makes it problematic and expensive to properly describe, schedule and monitor them. Use of conventional high-resolution survey tools in an archaeological context is changing the economic structure of such investigations however, and it is now possible to remotely but routinely monitor the state of submerged cultural artifacts. Use of such data to optimize expenditure of expensive and rare assets (e.g., divers and …


Analysis Of Nutraceuticals For Toxic Metals: Development And Validation Of Sample Preparation Method, Julia Cooper May 2007

Analysis Of Nutraceuticals For Toxic Metals: Development And Validation Of Sample Preparation Method, Julia Cooper

All Theses

With increasing numbers of health-conscious consumers purchasing nutraceutical supplements, total sales in the nutrition industry have soared to over $200 billion in 2006. It is important to assess the safety of these nutraceutical products, with specific regards to toxic metals, including arsenic, cadmium, lead, and mercury. Because species of these metals may be more toxic than others, they can have hazardous health effects if ingested in excess quantities. The work described in this thesis focuses on the development of a sample preparation method for nutraceutical products, specifically ethanolic tinctures and glycerin-based matrices, and analysis of these products by inductively coupled …


Keck Hires Spectroscopy Of Candidate Post T Tauri Stars, Eric Bubar May 2007

Keck Hires Spectroscopy Of Candidate Post T Tauri Stars, Eric Bubar

All Theses

This work utilizes an age-oriented method to identify isolated post T Tauri stars in a 13-star sample of high resolution spectroscopy from the 10-m Keck telescope. This analysis utilizes qualitative age information derived from lithium abundances, chromospheric emission indices and UVW kinematic motions in analyzing positions in the the H-R diagram. Once qualitatively assigned a ``young'' age, pre-main sequence isochrones are utilized to determine stellar mass and age estimates. Through this method, 5 of the 13 stars have been confirmed as being in the post T Tauri class. We also examine irregular photometric variability of PTTs and compare the homology …


Gamma Ray Burst Afterglow Observations, Adria Updike May 2007

Gamma Ray Burst Afterglow Observations, Adria Updike

All Theses

Gamma ray bursts (GRBs) are among the most luminous explosions in the universe. We present an overview of the observational history of GRBs and the mechanisms involved, then focus on one burst in particular, GRB 070125 and our observational campaign. Finally, we present the results of a model of the global optical response to GRBs, and make recommendations as to how we could improve the global response in preparation for upcoming satellite missions.


Air Monitoring Of Some Air Pollutants In Al-Ain City Using Passive Samplers, By Ismail Abdel Karim El Haty May 2007

Air Monitoring Of Some Air Pollutants In Al-Ain City Using Passive Samplers, By Ismail Abdel Karim El Haty

Theses

Air pollution monitoring is highly valuable due to effects on economics and public health. Hence, concerned authorities in different countries as well as the World Health Organization (WHO) specified the permitted standard concentration of the main pollutants. Large number of countries also have built their air quality monitoring stations, and distributed them in several sites to monitor air pollutants over the whole year. Some developed countries established an awareness environmental program to educate the public and inform them of daily pollution level to take necessary precautions.

In this study, air pollution was monitored in AI-Ain City over twelve months, through …


New Applications Of The Pauson-Khand Reaction And Studies Towards The Synthesis Of The Hamigerans, Christian Emeka Madu May 2007

New Applications Of The Pauson-Khand Reaction And Studies Towards The Synthesis Of The Hamigerans, Christian Emeka Madu

Chemistry & Biochemistry Dissertations

This dissertation is divided into two parts. The first part describes the dicobalt octacarbonyl mediated synthesis of medium sized rings via intramolecular Pauson-Khand (IMPK) reaction. The cyclization of 1,8-enynes has proved to be difficult via the IMPK reaction due to entropy reasons. To overcome thid limitation we attempted this cyclization in the presence of an ortho- buttressing group (t-butyl group) on the aromatic ring so as to reduce the conformationally allowed volume of the alkene arm of the substrate. The construction of the substrates started with O-alkenylation of the commercially available 3,5 di-tert-butyl-2-hydroxylbenzaldehyde and then the O-alkenylation products were alkynylated …


Study Of Oxide Surfaces Using Time Of Flight Positron Annihilation Induced Auger Electron Spectroscopy, Manori Prasadika Nadesalingam May 2007

Study Of Oxide Surfaces Using Time Of Flight Positron Annihilation Induced Auger Electron Spectroscopy, Manori Prasadika Nadesalingam

Physics Dissertations

Transition metal oxides (TMOs) exhibit a rich collection of interesting and intriguing properties which can be used for wide variety of applications. In this dissertation, I will discuss the first PAES measurements on vacuum anneal induced changes in the surface layers of Cu2O/Ta, Cu 2O/TCO and oxidized Cu(100) prepared by spray coated, electrochemically deposition and thermal oxidation techniques respectively. PAES measurements on Cu2O/TCO shows that the a very large increase in the intensity of the Cu (M2,3 VV) Auger peak after annealing at 250°C. Similar but significantly smaller changes were observed in the EAES spectra consistent with the fact that …