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2009

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Articles 6091 - 6120 of 6353

Full-Text Articles in Physical Sciences and Mathematics

Revealing The Copy And Paste Habits Of End Users, Kathryn T. Stolee, Sebastian Elbaum, Gregg Rothermel Jan 2009

Revealing The Copy And Paste Habits Of End Users, Kathryn T. Stolee, Sebastian Elbaum, Gregg Rothermel

School of Computing: Conference and Workshop Papers

Transferring data across applications is a common end user task, and copying and pasting via the clipboard lets users do so relatively easily. Using the clipboard, however, can also introduce inefficiencies and errors in user tasks. To help researchers and tool developers understand and address these problems, we studied how end users interact with the clipboard through cut, copy, and paste actions. This study was performed by logging clipboard interactions while end users performed everyday tasks. From the clipboard usage data, we have identified several usage patterns that describe how data is transferred within the desktop environment. Such patterns help …

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Soil Carbon And Nitrogen Accumulation In A Forested Debris Flow Chronosequence, California, Judith K. Turk, Robert C. Graham Jan 2009

Soil Carbon And Nitrogen Accumulation In A Forested Debris Flow Chronosequence, California, Judith K. Turk, Robert C. Graham

Conservation and Survey Division: Faculty and Staff Publications

The role of forest soils in the biogeochemical cycling of C and N is most dynamic during the early stages of soil development. To define C and N trends that occur with soil development in a mixed coniferous forest, a chronosequence formed by debris flows was studied. The accumulation rates of total organic C (TOC) and total N (TN) were evaluated in soils on 10 debris flow deposits, ranging from depth, since this was the depth of the shallowest debris flows. Carbon was found to accumulate in the organic horizons at a rate of 26.5 g m−2 yr−1 …

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Using Hadoop As A Grid Storage Element, Brian Bockelman Jan 2009

Using Hadoop As A Grid Storage Element, Brian Bockelman

School of Computing: Conference and Workshop Papers

Hadoop is an open-source data processing framework that includes a scalable, fault- tolerant distributed file system, HDFS. Although HDFS was designed to work in conjunction with Hadoop's job scheduler, we have re-purposed it to serve as a grid storage element by adding GridFTP and SRM servers. We have tested the system thoroughly in order to understand its scalability and fault tolerance. The turn-on of the Large Hadron Collider (LHC) in 2009 poses a significant data management and storage challenge; we have been working to introduce HDFS as a solution for data storage for one LHC experiment, the Compact Muon Solenoid …

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An Adaptive Steganography Scheme For Voice Over Ip, Hui Tian, Ke Zhou, Hong Jiang, Yongfeng Huang, Jin Liu, Dan Feng Jan 2009

An Adaptive Steganography Scheme For Voice Over Ip, Hui Tian, Ke Zhou, Hong Jiang, Yongfeng Huang, Jin Liu, Dan Feng

School of Computing: Conference and Workshop Papers

This paper presents an adaptive steganography scheme for Voice over IP (VoIP). Differing from existing steganography techniques for VoIP, this scheme enhances the embedding transparency by taking into account the similarity between Least Significant Bits (LSBs) and embedded messages. Moreover, we introduce the notion of Partial Similarity Value (PSV). By properly setting the threshold PSV, we can adaptively balance the embedding transparency and capacity. We evaluate the effectiveness of this scheme with G.729a as the codec of the cover speech in StegTalk, a covert communication system based on VoIP. The experimental results demonstrate that our technique provides better performance than …

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Density-Based Clustering Of Polygons, Deepti Joshi, Ashok Samal, Leen-Kiat Soh Jan 2009

Density-Based Clustering Of Polygons, Deepti Joshi, Ashok Samal, Leen-Kiat Soh

School of Computing: Conference and Workshop Papers

Clustering is an important task in spatial data mining and spatial analysis. We propose a clustering algorithm P-DBSCAN to cluster polygons in space. PDBSCAN is based on the well established density-based clustering algorithm DBSCAN. In order to cluster polygons, we incorporate their topological and spatial properties in the process of clustering by using a distance function customized for the polygon space. The objective of our clustering algorithm is to produce spatially compact clusters. We measure the compactness of the clusters produced using P-DBSCAN and compare it with the clusters formed using DBSCAN, using the Schwartzberg Index. We measure the effectiveness …

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An Adaptive Steganography Scheme For Voice Over Ip, Hui Tian, Ke Zhou, Hong Jiang, Yongfeng Huang, Jin Liu, Dan Feng Jan 2009

An Adaptive Steganography Scheme For Voice Over Ip, Hui Tian, Ke Zhou, Hong Jiang, Yongfeng Huang, Jin Liu, Dan Feng

School of Computing: Conference and Workshop Papers

This paper presents an adaptive steganography scheme for Voice over IP (VoIP). Differing from existing steganography techniques for VoIP, this scheme enhances the embedding transparency by taking into account the similarity between Least Significant Bits (LSBs) and embedded messages. Moreover, we introduce the notion of Partial Similarity Value (PSV). By properly setting the threshold PSV, we can adaptively balance the embedding transparency and capacity. We evaluate the effectiveness of this scheme with G.729a as the codec of the cover speech in StegTalk, a covert communication system based on VoIP. The experimental results demonstrate that our technique provides better performance than …

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Joint Computing And Network Resource Scheduling In A Lambda Grid Network, Vaidhehi Lakshmiraman, Byrav Ramamurthy Jan 2009

Joint Computing And Network Resource Scheduling In A Lambda Grid Network, Vaidhehi Lakshmiraman, Byrav Ramamurthy

School of Computing: Conference and Workshop Papers

Data-intensive Grid applications require huge data transfers between grid computing nodes. These computing nodes, where computing jobs are executed, are usually geographically separated. A grid network that employs optical wavelength division multiplexing (WDM) technology and optical switches to interconnect computing resources with dynamically provisioned multi-gigabit rate bandwidth lightpath is called a Lambda Grid network. A computing task may be executed on any one of several computing nodes which possesses the necessary resources. In order to reflect the reality in job scheduling, allocation of network resources for data transfer should be taken into consideration. However, few scheduling methods consider the communication …

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A Cooperative Scheme For Dynamic Window Resizing In P2p Live Streaming, Zhipeng Ouyang, Lisong Xu, Byrav Ramamurthy Jan 2009

A Cooperative Scheme For Dynamic Window Resizing In P2p Live Streaming, Zhipeng Ouyang, Lisong Xu, Byrav Ramamurthy

School of Computing: Conference and Workshop Papers

Due to their widespread popularity, Peer-to-Peer (P2P) live streaming systems have become a great challenge for Internet Service Providers (ISPs) as they consume huge amount of Internet bandwidth. By observing that different users may watch a channel with different window sizes, we propose a cooperative scheme called Partial Participation Scheme (PPS) in which different peers request a video stream at different rates based on their window sizes, and a subset of peers viewing the video stream using a small window work as helpers to forward extra data to help other peers using a large window. By reducing streaming rate received …

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Error Control In Wireless Sensor Networks: A Cross Layer Analysis, Mehmet C. Vuran, Ian F. Akyildiz Jan 2009

Error Control In Wireless Sensor Networks: A Cross Layer Analysis, Mehmet C. Vuran, Ian F. Akyildiz

School of Computing: Faculty Publications

Error control is of significant importance for Wireless Sensor Networks (WSNs) because of their severe energy constraints and the low power communication requirements. In this paper, a cross-layer methodology for the analysis of error control schemes in WSNs is presented such that the effects of multi-hop routing and the broadcast nature of the wireless channel are investigated. More specifically, the cross-layer effects of routing, medium access, and physical layers are considered. This analysis enables a comprehensive comparison of forward error correction (FEC) codes, automatic repeat request (ARQ), and hybrid ARQ schemes in WSNs. The validation results show that the developed …

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Tuning The Electronic Properties Of The Golden Buckyball By Endohedral Doping: M@Au16− (M=Ag,Zn, In), Lei-Ming Wang, Rhitankar Pal, Wei Huang, Xiao Cheng Zeng, Lai-Sheng Wang Jan 2009

Tuning The Electronic Properties Of The Golden Buckyball By Endohedral Doping: M@Au16− (M=Ag,Zn, In), Lei-Ming Wang, Rhitankar Pal, Wei Huang, Xiao Cheng Zeng, Lai-Sheng Wang

Xiao Cheng Zeng Publications

The golden Au16- cage is doped systematically with an external atom of different valence electrons: Ag, Zn, and In. The electronic and structural properties of the doped clusters, MAu16- (M =Ag,Zn, In), are investigated by photoelectron spectroscopy and theoretical calculations. It is observed that the characteristic spectral features of 16-, reflecting its near tetrahedral (Td) symmetry, are retained in the photoelectron spectra of MAu16-, suggesting endohedral structures with little distortion from the parent Au16- cage for the doped clusters. Density functional calculations show that …

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Dipole-Induced, Thermally Stable Lamellar Structure By Polar Aromatic Silane, Jinyue Jiang, Ocelio V. Lima, Yong Pei, Xiao Cheng Zeng, Li Tan, Eric Forsythe Jan 2009

Dipole-Induced, Thermally Stable Lamellar Structure By Polar Aromatic Silane, Jinyue Jiang, Ocelio V. Lima, Yong Pei, Xiao Cheng Zeng, Li Tan, Eric Forsythe

Xiao Cheng Zeng Publications

Lamellar structures, consisting of alternating inorganic layers separated by organic moieties, have attracted much attention over a wide range of applications, such as polymer-clay composites, rheology control, and optoelectronic devices. Organosilanes are ideal candidates for such efforts due to their ability to self-assemble and the intrinsic hybrid configuration of organic/inorganic moieties. Yet, the main emphasis has been focused on alkylsilane, where an alkyl group is linked with a silane terminal, i.e., R-SiX3 (R is alkane and X can be halogen or alkoxy). Construction of stacked monolayers of alkylsilane through chemisorption is possible. The demonstrated pathway usually takes place after …

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Materials Design Of Half-Metallic Graphene And Graphene Nanoribbons, Menghao Wu, Xiaojun Wu, Yi Gao, Xiao Cheng Zeng Jan 2009

Materials Design Of Half-Metallic Graphene And Graphene Nanoribbons, Menghao Wu, Xiaojun Wu, Yi Gao, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Through patterned chemical modification, we show that both graphene sheets and zigzag-edged graphene nanoribbons (ZGNRs) can be converted to half-metals as long as the unmodified carbon strip (or width of ZGNRs) is sufficiently wide. Periodically functionalized graphene can mimic electronic behavior of edge-modified ZGNRs as the edge-modified zigzag carbon chains effectively divide a graphene sheet into a series of identical ZGNRs.

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On The Phase Diagram Of Water With Density Functional Theory Potentials: The Melting Temperature Of Ice /H With The Perdew–Burke–Ernzerhof And Becke–Lee–Yang–Parr Functionals, Soohaeng Yoo, Xiao Cheng Zeng, Sotiris C. Xantheas Jan 2009

On The Phase Diagram Of Water With Density Functional Theory Potentials: The Melting Temperature Of Ice /H With The Perdew–Burke–Ernzerhof And Becke–Lee–Yang–Parr Functionals, Soohaeng Yoo, Xiao Cheng Zeng, Sotiris C. Xantheas

Xiao Cheng Zeng Publications

The melting temperature (Tm) of ice Ih was determined from constant enthalpy and pressure (NPH) Born–Oppenheimer molecular dynamics simulations to be 417±3 K for the Perdew–Burke– Ernzerhof and 411±4 K for the Becke–Lee–Yang–Parr density functionals using a coexisting ice (Ih)-liquid phase at constant pressures of P=2500 and 10 000 bar and a density p=1 g/cm3, respectively.

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First-Principles Study Of Methane Dehydrogenation On A Bimetallic Cu/N(111) Surface, Wei An, Xiao Cheng Zeng, C. Heath Turner Jan 2009

First-Principles Study Of Methane Dehydrogenation On A Bimetallic Cu/N(111) Surface, Wei An, Xiao Cheng Zeng, C. Heath Turner

Xiao Cheng Zeng Publications

We present density-functional theory calculations of the dehydrogenation of methane and CHx (x = 1 – 3) on a Cu/Ni(111) surface, where Cu atoms are substituted on the Ni surface at a coverage of 1/4 monolayer.

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Noncovalent Interactions In The Asymmetric Synthesis Of Rigid, Conjugated Helical Structures, Makoto Miyasaka, Maren Pink, Suchada Rajca, Andrzej Rajca Jan 2009

Noncovalent Interactions In The Asymmetric Synthesis Of Rigid, Conjugated Helical Structures, Makoto Miyasaka, Maren Pink, Suchada Rajca, Andrzej Rajca

Andrzej Rajca Publications

Helical supramolecular architecture, such as helical foldamers, supramolecular helicates and aggregates, helical molecules, macromolecules, and oligomers, is a fascinating topic of interest in chemistry and materials science. Although such supramolecular structures may provide advantages in the design of stimuli-responsive and functional materials, the weak nature of the noncovalent forces, as well as the dependency of the dynamic process on their local environments, may hinder their possible applications because of their limited structural stability and processibility. Stabilization of these supramolecular structures could be achieved by modification of the molecular backbone with specific functional groups that permit intramolecular cross-linking, in which covalent …

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Paleolimnological Evidence Of The Effects On Lakes Of Energy And Mass Transfer From Climate And Humans, Peter R. Leavitt, Sherilyn C. Fritz, N. J. Anderson, P. A. Baker, T. Blenckner, L. Bunting, J. Catalan, D. J. Conley, W. O. Hobbs, E. Jeppesen, A. Korhola, S. Mcgowan, K. Rühland, J. A. Rusak, G. L. Simpson, N. Solovieva, J. Werne Jan 2009

Paleolimnological Evidence Of The Effects On Lakes Of Energy And Mass Transfer From Climate And Humans, Peter R. Leavitt, Sherilyn C. Fritz, N. J. Anderson, P. A. Baker, T. Blenckner, L. Bunting, J. Catalan, D. J. Conley, W. O. Hobbs, E. Jeppesen, A. Korhola, S. Mcgowan, K. Rühland, J. A. Rusak, G. L. Simpson, N. Solovieva, J. Werne

Department of Earth and Atmospheric Sciences: Faculty Publications

The premise of this article is that climate effects on lakes can be quantified most effectively by the integration of process-oriented limnological studies with paleolimnological research, particularly when both disciplines operate within a common conceptual framework. To this end, the energy (E)–mass (m) flux framework (Em flux) is developed and applied to selected retrospective studies to demonstrate that climate variability regulates lake structure and function over diverse temporal and spatial scales through four main pathways: rapid direct transfer of E to the lake surface by irradiance, heat, and wind; slow indirect effects of E via changes in …

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Estimating Hydraulic Conductivity From Drainage Patterns Derived From Dem -- A Case Study In The Oregon Cascades, B. P. Grudzinski, W. Luo, Daryll Pederson Jan 2009

Estimating Hydraulic Conductivity From Drainage Patterns Derived From Dem -- A Case Study In The Oregon Cascades, B. P. Grudzinski, W. Luo, Daryll Pederson

Department of Earth and Atmospheric Sciences: Faculty Publications

Hydraulic conductivity is an important parameter in hydrology which describes the ease with which water moves through porous media. This parameter is also important in understanding the hydrology of Mars. On Earth, this parameter can be measured by conducting controlled experiments in laboratories or conducting pumping tests in the field. This study introduces a new method of estimating hydraulic conductivity from drainage dissection pattern derived from digital elevation model (DEM). This method can be applied to Mars if it is robustly tested on Earth.

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Obliquity-Paced Pliocene West Antarctic Ice Sheet Oscillations, T. Naish, R. D. Powell, R. Levy, G. Wilson, R. Scherer, F. Talarico, L. Krissek, F. Niessen, M. Pompilio, T. J. Wilson, L. Carter, R. Deconto, P. Huybers, R. Mckay, D. Pollard, J. Ross, D. Winter, P. Barrett, G. Browne, R. Cody, E. A. Cowan, J. Crampton, G. Dunbar, N. Dunbar, F. Florindo, C. Gebhardt, I. Graham, M. Hannah, D. Hansaraj, David M. Harwood, D. Helling, S. Henrys, L. Hinnov, G. Kuhn, P. Kyle, A. La¨Ufer, P. Maffioli, D. Magens, K. Mandernack, W. Mcintosh, C. Millan, R. Morin, C. Ohneiser, T. Paulsen, D. Persico, I. Raine, J. Reed, C. Riesselman, L. Sagnotti, D. Schmitt, C. Sjunneskog, P. Strong, M. Taviani, S. Vogel, T. Wilch, T. Williams Jan 2009

Obliquity-Paced Pliocene West Antarctic Ice Sheet Oscillations, T. Naish, R. D. Powell, R. Levy, G. Wilson, R. Scherer, F. Talarico, L. Krissek, F. Niessen, M. Pompilio, T. J. Wilson, L. Carter, R. Deconto, P. Huybers, R. Mckay, D. Pollard, J. Ross, D. Winter, P. Barrett, G. Browne, R. Cody, E. A. Cowan, J. Crampton, G. Dunbar, N. Dunbar, F. Florindo, C. Gebhardt, I. Graham, M. Hannah, D. Hansaraj, David M. Harwood, D. Helling, S. Henrys, L. Hinnov, G. Kuhn, P. Kyle, A. La¨Ufer, P. Maffioli, D. Magens, K. Mandernack, W. Mcintosh, C. Millan, R. Morin, C. Ohneiser, T. Paulsen, D. Persico, I. Raine, J. Reed, C. Riesselman, L. Sagnotti, D. Schmitt, C. Sjunneskog, P. Strong, M. Taviani, S. Vogel, T. Wilch, T. Williams

Department of Earth and Atmospheric Sciences: Faculty Publications

Thirty years after oxygen isotope records frommicrofossils deposited in ocean sediments confirmed the hypothesis that variations in the Earth’s orbital geometry control the ice ages1, fundamental questions remain over the response of the Antarctic ice sheets to orbital cycles2. Furthermore, an understanding of the behaviour of the marinebased West Antarctic ice sheet (WAIS) during the ‘warmerthan- present’ early-Pliocene epoch ( ~5–3Myr ago) is needed to better constrain the possible range of ice-sheet behaviour in the context of future global warming3. Here we present a marine glacial record from the upper 600mof the AND-1B sediment …

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Biostratigraphy Of The Hunter Creek Sandstone, Verdi Basin, Washoe County, Nevada, Thomas S. Kelly, Ross Secord Jan 2009

Biostratigraphy Of The Hunter Creek Sandstone, Verdi Basin, Washoe County, Nevada, Thomas S. Kelly, Ross Secord

Department of Earth and Atmospheric Sciences: Faculty Publications

The Hunter Creek Sandstone of the Verdi Basin, Nevada, yielded a succession of superposed continental faunal assemblages ranging in age from the late Clarendonian (late Miocene) through the late Blancan (late Pliocene) in the North American land mammal age framework, or ca. 10.5-2.5 Ma. We describe two new local faunas from the Hunter Creek Sandstone: the East Verdi local fauna, of late-medial to late Clarendonian age, which includes Dinohippus cf. D. leardi, Camelidae, ?Antilocapridae, and Mammutidae or Gomphotheriidae; and the Mogul local fauna, of Hemphillian age, which includes Dinohippus sp., Rhinocerotidae, Camelidae (at least two species), Mammut sp., and …

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High-Resolution Calcareous Nannofossil Biostratigraphy For The Coniacian/Santonian Stage Boundary, Western Interior Basin, Stacie A. Blair, David K. Watkins Jan 2009

High-Resolution Calcareous Nannofossil Biostratigraphy For The Coniacian/Santonian Stage Boundary, Western Interior Basin, Stacie A. Blair, David K. Watkins

Department of Earth and Atmospheric Sciences: Faculty Publications

The Ten Mile Creek area (Dallas, Texas) is a proposed Global Stratotype Section and Point (GSSP) candidate for the Coniacian/Santonian Stage boundary. The Santonian Working Group has designated the first appearance of Inoc¬eramus (Cladoceramus) undulatoplicatus as the diagnostic macrofossil bioevent for the base of the Santonian Stage. Cal¬careous nannofossils were examined from sediments of the Bruceville Marl at the proposed GSSP site and from well-preserved sediments of the coeval Smoky Hill Member-type area (northwestern Kansas) of the Niobrara Formation. Nannofossil bioevents were correlated with the lowest stratigraphic occurrence of I. undulatoplicatus to create a high resolution biostratigraphic framework and stratigraphic …

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Paleohydrology Of Kangerlussuaq (Søndre Strømfjord), West Greenland During The Last ~8,000 Years, Frank Aebly, Sherilyn C. Fritz Jan 2009

Paleohydrology Of Kangerlussuaq (Søndre Strømfjord), West Greenland During The Last ~8,000 Years, Frank Aebly, Sherilyn C. Fritz

Department of Earth and Atmospheric Sciences: Faculty Publications

Major fluctuations of hydroclimate in West Greenland are recorded in paleoshoreline terraces that encircle several lakes near Kangerlussuaq, Greenland (67°01’N, 50°40’W). Geomorphic and stratigraphic analyses were used to construct a lake-level curve for Hunde Sø, a large closed-basin lake in this region. Changes in lake volume associated with lake-level fluctuations were calculated, and a water-balance model was used to determine the primary factors influencing lake volume and the changes in those factors necessary to affect reconstructed lake-level change. Sensitivity tests suggest that mean annual precipitation and the relative proportion of summer versus winter precipitation are the primary climate drivers of …

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Multi-Site Photometry Of The Pulsating Herbig Ae Star V346 Ori, S Bernabei, T D. Oswalt Jan 2009

Multi-Site Photometry Of The Pulsating Herbig Ae Star V346 Ori, S Bernabei, T D. Oswalt

Aerospace, Physics, and Space Science Faculty Publications

Context. The study of pulsation in pre-main-sequence intermediate-mass stars represents an important tool for deriving information about fundamental stellar parameters and internal structure, as well as testing theoretical models. Interest in this class of variable stars has increased significantly during the last decade and about 30 members are presently known in the literature. Aims. After constructing the frequency spectrum of oscillations in V346 Ori, we apply asteroseismic tools to these data to estimate the intrinsic parameters (mass, luminosity, effective temperature) of V346 Ori and obtain information about its internal structure. Methods. CCD time-series photometry in the Johnson V filter was …

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Spectral Dependence Of Terrestrial Gamma-Ray Flashes On Source Distance, Bryna J. Hazelton, Brian W. Grefenstette, David M. Smith, Joseph R. Dwyer, Xuanmin Shao, Steven A. Cummer, Themis G. Chronis, Erin H. Lay, Robert H. Holzworth Jan 2009

Spectral Dependence Of Terrestrial Gamma-Ray Flashes On Source Distance, Bryna J. Hazelton, Brian W. Grefenstette, David M. Smith, Joseph R. Dwyer, Xuanmin Shao, Steven A. Cummer, Themis G. Chronis, Erin H. Lay, Robert H. Holzworth

Aerospace, Physics, and Space Science Faculty Publications

We use lightning sferics from the World Wide Lightning Location Network to identify storms near 362 Terrestrial Gamma-ray Flashes (TGFs). The combined spectrum of TGFs with storms within 300 km of the sub-satellite point is much harder than the spectrum of TGFs with more distant storms. When these data are compared with simulations of vertically oriented relativistic runaway breakdown, it is found that the most likely model has a source altitude of 15 km and a wide-beam geometry. We find four associations of TGFs with individual sferics geolocated to positions more than 300 km from the sub-satellite point and show …

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Preliminary Xcov26 Results For Ec14012-1446, Judith L. Provençal, Matt A. Wood, Stéphane Vennes Jan 2009

Preliminary Xcov26 Results For Ec14012-1446, Judith L. Provençal, Matt A. Wood, Stéphane Vennes

Aerospace, Physics, and Space Science Faculty Publications

EC14012-1446 is a hydrogen atmosphere (DA) white dwarf pulsator. Its rich pulsation spectrum displays a range of excited modes with complex multiplet structure, in addition to numerous combination frequencies. In April 2008, EC14012-1446 was the primary target of XCOV26. We obtained over 300 hrs of nearly continuous high speed photometry with the goal of using the nonlinear pulse shapes to empirically determine the parameters of the convection zone. The Fourier transform (FT) of the light curve contains power between 1000 to 4000 μHz, with the dominant peak at 1234 μHz. We find 13 independent frequencies distributed in 8 modes, as …

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Fuse Observations Of Intermediate Temperature Da: Atmospheric Parameters And Metal Abundances, Jean François Dupuis, Vincent Hénault-Brunet, Perre Chayer, Stéphane Vennes, Jeffrey W. Kruk Jan 2009

Fuse Observations Of Intermediate Temperature Da: Atmospheric Parameters And Metal Abundances, Jean François Dupuis, Vincent Hénault-Brunet, Perre Chayer, Stéphane Vennes, Jeffrey W. Kruk

Aerospace, Physics, and Space Science Faculty Publications

We present results from our analysis of a sample of DA white dwarfs having effective temperature below 25,000 K observed with the FUSE satellite with the goals of better understanding the origin of metals detected in the atmosphere of these stars. When possible, we combine the FUSE spectra with the IUE spectra and determine atmospheric parameters by fitting the Lyman line profiles. In general we find a good agreement with published values based on fits of the Balmer series. We observe that the continuum in the blue wing of the Lyman α line profile is generally lower in comparison with …

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The Tata-Binding Protein Core Domain In Solution Variably Bends Tata Sequences Via A Three-Step Binding Mechanism [Tables & Figures], Roberto F. Delgadillo, Jodell E. Whittington, Laura K. Parkhurst, Lawrence J. Parkhurst Jan 2009

The Tata-Binding Protein Core Domain In Solution Variably Bends Tata Sequences Via A Three-Step Binding Mechanism [Tables & Figures], Roberto F. Delgadillo, Jodell E. Whittington, Laura K. Parkhurst, Lawrence J. Parkhurst

Lawrence Parkhurst Publications

Studies of the binding and bending of the AdMLP TATA sequence (TATAAAAG) by the core domain of yeast TBP allow quantitation of the roles of the N-terminal domains of yeast and human TBP. All three proteins bind DNA via a three-step mechanism with no evidence for an initially bound but unbent DNA. The large enthalpy and entropy of activation for the first step in yTBP binding can now be assigned to movement of the NTD from the DNA binding pocket and not to energetics of DNA bending. The energetic patterns for hTBP and cTBP suggest that the …

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A System For Estimating Bowen Ratio And Evaporation From Waste Lagoons, Rezaul Mahmood Jan 2009

A System For Estimating Bowen Ratio And Evaporation From Waste Lagoons, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

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Farmers And Nature Conservation: What Is Known About Attitudes, Context Factors And Actions Affecting Conservation?, Johan Ahnström, Jenny Höckert, Hanna L. Bergea, Charles A. Francis, Peter Skelton, Lars Hallgren Jan 2009

Farmers And Nature Conservation: What Is Known About Attitudes, Context Factors And Actions Affecting Conservation?, Johan Ahnström, Jenny Höckert, Hanna L. Bergea, Charles A. Francis, Peter Skelton, Lars Hallgren

Department of Agronomy and Horticulture: Faculty Publications

Farmers’ attitudes towards viability of specific conservation practices or actions strongly impact their decisions on adoption and change. This review of ‘attitude’ information reveals a wide range of perceptions about what conservation means and what the impacts of adoption will mean in economic and environmental terms. Farmers operate in a tight financial situation, and in parts of the world they are highly dependent on government subsidies, and cannot afford to risk losing that support. Use of conservation practices is most effective when these are understood in the context of the individual farm, and decisions are rooted in land and resource …

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Farming Systems Education: Case Study Of Swedish Test Pilots, Lennart Salomonsson, Anna Nilsson, Sofia Palmer, Adam Roigart, Charles A. Francis Jan 2009

Farming Systems Education: Case Study Of Swedish Test Pilots, Lennart Salomonsson, Anna Nilsson, Sofia Palmer, Adam Roigart, Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

We describe and analyze a pedagogical experiment that introduced a broad and holistic perspective on complete farming systems, systemic learning tools, and a participatory learning strategy at an early stage in agronomy education. The paper describes the adventure of three students, who came from a conventional agronomy program at the Swedish University of Agricultural Sciences (SLU), who were frustrated with the lack of integrated approaches to the study of agricultural systems and a strong focus on molecular-level processes in their first year of education. They encountered a narrow focus in most courses and the overall curricula of agricultural education that …

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Matrix Geochemistry And Phytophthora Occurrence On Reforested Mine Lands In Appalachia, Kathryn M. Ward Jan 2009

Matrix Geochemistry And Phytophthora Occurrence On Reforested Mine Lands In Appalachia, Kathryn M. Ward

University of Kentucky Master's Theses

At the Bent Mountain surface mine, Pike County, Kentucky, a study has been ongoing since 2005 to assess the influence of various types of loose-graded mine spoils on water quality and forest establishment. Six research plots consist of two replicates of brown weathered sandstone, gray unweathered sandstone, and mixed brown sandstone, gray sandstone, and shale that were emplaced according to Forestry Reclamation Approach criteria. A series of analyses was initiated in 2007 to examine influence of spoil matrix composition on sulfate and carbonate geochemistry of infiltrated waters, as well as to investigate the occurrence of Phytophthora, a group of …

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