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2007

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Articles 3631 - 3660 of 6758

Full-Text Articles in Physical Sciences and Mathematics

Live Surface, Christopher J. Armstrong Feb 2007

Live Surface, Christopher J. Armstrong

Theses and Dissertations

Live Surface allows users to segment and render complex surfaces from 3D image volumes at interactive (sub-second) rates using a novel, Cascading Graph Cut (CGC). Live Surface consists of two phases. (1) Preprocessing for generation of a complete 3D watershed hierarchy followed by tracking of all catchment basin surfaces. (2) User interaction in which, with each mouse movement, the 3D object is selected and rendered in real time. Real-time segmentation is ccomplished by cascading through the 3D watershed hierarchy from the top, applying graph cut successively at each level only to catchment basins bordering the segmented surface from the previous …


Nonlinear Inflaton Fragmentation After Preheating, Gary Felder, Lev Kofman Feb 2007

Nonlinear Inflaton Fragmentation After Preheating, Gary Felder, Lev Kofman

Physics: Faculty Publications

We consider the nonlinear dynamics of inflaton fragmentation during and after preheating in the simplest model of chaotic inflation. While the earlier regime of parametric resonant particle production and the later turbulent regime of interacting fields evolving towards equilibrium are well identified and understood, the short intermediate stage of violent nonlinear dynamics remains less explored. Lattice simulations of fully nonlinear preheating dynamics show specific features of this intermediate stage: occupation numbers of the scalar particles are peaked, scalar fields become significantly nongaussian and the field dynamics become chaotic and irreversible. Visualization of the field dynamics in position space reveals that …


The N-Terminal Domain Of Alphab-Crystallin Is Protected From Proteolysis By Bound Substrate, J. A. Aquilina, S. J. Watt Feb 2007

The N-Terminal Domain Of Alphab-Crystallin Is Protected From Proteolysis By Bound Substrate, J. A. Aquilina, S. J. Watt

Faculty of Science - Papers (Archive)

alpha-Crystallin, a major structural protein of the lens can also function as a molecular chaperone by binding to unfolding substrate proteins. We have used a combination of limited proteolysis at low temperature, and mass spectrometry to identify the regions of alpha-crystallin directly involved in binding to the structurally compromised substrate, reduced alpha-lactalbumin. In the presence of trypsin, alpha-crystallin which had been pre-incubated with substrate showed markedly reduced proteolysis at the C-terminus compared with a control, indicating that the bound substrate restricted access of trypsin to R157, the main cleavage site. Chymotrypsin was able to cleave at residues in both the …


Use Of Diazacon™ As A Reproductive Inhibitor For Monk Parakeets (Myiopsitta Monachus), Christi A. Yoder, Michael L. Avery, Kandy L. Keacher, Eric A. Tillman Feb 2007

Use Of Diazacon™ As A Reproductive Inhibitor For Monk Parakeets (Myiopsitta Monachus), Christi A. Yoder, Michael L. Avery, Kandy L. Keacher, Eric A. Tillman

United States Department of Agriculture Wildlife Services: Staff Publications

Feral monk parakeet (Myiopsitta monachus) populations have become established in the United States and other countries around the world, and can cause damage to electrical facilities. Because the monk parakeet is a highly visible species and there is often public opposition to lethal control measures, non-lethal methods, such as contraception, are being developed to help control the spread of feral populations. Two gavage studies and one ad libitum nesting study were conducted to assess the efficacy of DiazaCon™ as a potential contraceptive for the monk parakeet. The first gavage study compared daily dose levels of 0, 50, 75, …


How I Produced Nationally Award Winning Alfalfa Hay, Rick Alexander Feb 2007

How I Produced Nationally Award Winning Alfalfa Hay, Rick Alexander

Kentucky Alfalfa and Stored Forage Conference

No abstract provided.


Roundup Ready Alfalfa: Results After One Year On The Market, S. Ray Smith Feb 2007

Roundup Ready Alfalfa: Results After One Year On The Market, S. Ray Smith

Kentucky Alfalfa and Stored Forage Conference

Roundup Ready alfalfa has now been on the market for over a year with close to 30 varieties available or soon to be available across the U.S. This technology provides many new options for alfalfa producers in Kentucky. Several people have asked us which variety is highest yielding and unfortunately we have not been able to provide a good answer. The technology is so new (just approved fall 2005) that few of these varieties have been entered into University yield trials. Companies do have some private data, but they often don’t compare to the varieties you are familiar with. So …


Cowpea Aphids: Where Did They Come From, Will They Be Back?, Lee H. Townsend Feb 2007

Cowpea Aphids: Where Did They Come From, Will They Be Back?, Lee H. Townsend

Kentucky Alfalfa and Stored Forage Conference

Clearly, something was unusual back in March when large numbers of very dark aphids were found covering stems and tips in Logan, Marion, and Barren counties. They were the cowpea aphid or black legume aphid (Aphis craccivora), a sap-feeding insect known to occur in at least 28 states scattered over the US and into Canada. The cowpea aphid is the only black aphid found infesting alfalfa. Winged or wingless adults are usually shiny black, while the smaller nymphs are dull gray to black. Usually. they are lined along stems or clustered in the expanding leaf tips.


Hay Heating, Hay Sweat And Spontaneous Combustion, Tom Keene, Doug Overhults Feb 2007

Hay Heating, Hay Sweat And Spontaneous Combustion, Tom Keene, Doug Overhults

Kentucky Alfalfa and Stored Forage Conference

Making hay in central Kentucky can be one of the most trying on farm endeavors a producer can undertake. Our plentiful moisture, rolling topography, and climate make Kentucky ideal for producing high quality forage for either grazing or hay making. However, that same moisture either in the form of rain or high humidity can sometimes make it devilishly hard to make quality hay here in Kentucky.


Alfalfa For Summer Grazing, John Johns Feb 2007

Alfalfa For Summer Grazing, John Johns

Kentucky Alfalfa and Stored Forage Conference

Alfalfa can make an excellent grazing forage for cattle in the summer as well as at other times of year provided that good grazing management is utilized. Alfalfa can be grazed very close to the ground but should not be grazed continuously. Initial regrowth after grazing comes from nutrient reserves in the root; therefore, a sufficient rest period or regrowth period without grazing must be allowed for these nutrients to be replenished. In summer, this rest period is 30 to 35 days. In adequate rest for root nutrient replenishment is not allowed, the plant will be weakened and stand life …


Alfalfa Hay For Horses, Robert Coleman Feb 2007

Alfalfa Hay For Horses, Robert Coleman

Kentucky Alfalfa and Stored Forage Conference

Horses are designed to eat forage and quality forage is the basis for the feeding programs of all classes of horse. However, when one considers hay as that basic forage, what criteria are used to describe quality horse hay? In general terms, quality horse hay should supply needed nutrients, be palatable and should be free of anything harmful to the horse.


Requirements For Successful Alfalfa Establishment, Garry D. Lacefield Feb 2007

Requirements For Successful Alfalfa Establishment, Garry D. Lacefield

Kentucky Alfalfa and Stored Forage Conference

Establishing a good stand of alfalfa is expensive and time consuming, but the success rate is high if you give attention to the important factors. The following steps won’t insure success, but will increase greater likelihood.


How The Alfalfa Plant Grows: Impact On Management, S. Ray Smith Feb 2007

How The Alfalfa Plant Grows: Impact On Management, S. Ray Smith

Kentucky Alfalfa and Stored Forage Conference

Alfalfa is the premier forage crop with high yield, high forage quality, season long productivity, drought tolerance, and extended stand life. Alfalfa requires intensive management to insure that yield, quality, and stand life are maximized. It should be planted on deep, well drained soils and maintained with optimal fertilizer inputs. It also requires adequate rest periods between cutting for hay or grazing. Alfalfa can be prone to significant insect damage and stands may require insecticide treatments. There are many details to successfully managing an alfalfa stand, but if you understand how the plant grows then you will better understand the …


Alfalfa Information On The Web, Scott Flynn Feb 2007

Alfalfa Information On The Web, Scott Flynn

Kentucky Alfalfa and Stored Forage Conference

No abstract provided.


Foreword And Recipients Of Kentucky Alfalfa Awards [2007], Garry D. Lacefield, Christi L. Forsythe Feb 2007

Foreword And Recipients Of Kentucky Alfalfa Awards [2007], Garry D. Lacefield, Christi L. Forsythe

Kentucky Alfalfa and Stored Forage Conference

No abstract provided.


Concatenative Text-To-Speech Synthesis: A Study On Standard Colloquial Bengali., Soumen Chowdhury Dr. Feb 2007

Concatenative Text-To-Speech Synthesis: A Study On Standard Colloquial Bengali., Soumen Chowdhury Dr.

Doctoral Theses

The primary communication process between human beings is Speech. Speech synthesis is the automatic and artificial generation of the speech signal by a machine. A TTS (Text-To-Speech) synthesis system is one which can generate speech signal from a string of text in a given language. The development in the speech synthesis systems in various languages has been going on for several decades. With the unprecedented expansion of IT (Information Technology) invading the life of the common man it is highly desirable that at least the information dissemination be made via the speech mode which is the most natural mode of …


Modeling And Simulation Of Longitudinal Dynamics For Low Energy Ring-High Energy Ring At The Positron-Electron Project, C. Rivetta, Themis Mastorides, J.D. Fox, D. Teytelman, D. Van Winkle Feb 2007

Modeling And Simulation Of Longitudinal Dynamics For Low Energy Ring-High Energy Ring At The Positron-Electron Project, C. Rivetta, Themis Mastorides, J.D. Fox, D. Teytelman, D. Van Winkle

Physics

A time domain dynamic modeling and simulation tool for beam-cavity interactions in the Low Energy Ring (LER) and High Energy Ring (HER) at the Positron-Electron Project (PEP-II) is presented. Dynamic simulation results for PEP-II are compared to measurements of the actual machine. The motivation for this tool is to explore the stability margins and performance limits of PEP-II radio-frequency (RF) systems at future higher currents and upgraded RF configurations. It also serves as a test bed for new control algorithms and can define the ultimate limits of the low-level RF (LLRF) architecture. The time domain program captures the dynamic behavior …


Blackbird Use And Damage Of Wildlife Conservation Sunflower Plots: The Second Year, Jonathan M. Raetzman, George M. Linz, William J. Bleier Feb 2007

Blackbird Use And Damage Of Wildlife Conservation Sunflower Plots: The Second Year, Jonathan M. Raetzman, George M. Linz, William J. Bleier

United States Department of Agriculture Wildlife Services: Staff Publications

Annual blackbird damage to sunflower is valued at $5 to $10 million. Perhaps more importantly, the National Sunflower Association has identified blackbirds as the key reason for growers to abandon sunflower in areas of prime production. North Dakota and South Dakota together produce approximately 70% of sunflower grown in the United States. This crop adds $906 million to the regional economy. To date, cost effective and environmentally safe methods to reduce bird damage to sunflower remain elusive. In the 1980’s, scientists from the National Wildlife Research Center (NWRC) showed that “decoy” sunflower plots can greatly reduce bird damage to local …


Guest Perspective: Energy Efficiency And Conservation: The Most Cost-Effective Approach To Climate Change, John Dernbach Feb 2007

Guest Perspective: Energy Efficiency And Conservation: The Most Cost-Effective Approach To Climate Change, John Dernbach

John C. Dernbach

No abstract provided.


Crystalline Order On Riemannian Manifolds With Variable Gaussian Curvature And Boundary, Mark Bowick, Luca Giomi Feb 2007

Crystalline Order On Riemannian Manifolds With Variable Gaussian Curvature And Boundary, Mark Bowick, Luca Giomi

Physics - All Scholarship

We investigate the zero temperature structure of a crystalline monolayer constrained to lie on a two-dimensional Riemannian manifold with variable Gaussian curvature and boundary. A full analytical treatment is presented for the case of a paraboloid of revolution. Using the geometrical theory of topological defects in a continuum elastic background we find that the presence of a variable Gaussian curvature, combined with the additional constraint of a boundary, gives rise to a rich variety of phenomena beyond that known for spherical crystals. We also provide a numerical analysis of a system of classical particles interacting via a Coulomb potential on …


Power Boosting In Genome-Wide Studies Via Methods For Multivariate Outcomes, Mary J. Emond Feb 2007

Power Boosting In Genome-Wide Studies Via Methods For Multivariate Outcomes, Mary J. Emond

UW Biostatistics Working Paper Series

Whole-genome studies are becoming a mainstay of biomedical research. Examples include expression array experiments, comparative genomic hybridization analyses and large case-control studies for detecting polymorphism/disease associations. The tactic of applying a regression model to every locus to obtain test statistics is useful in such studies. However, this approach ignores potential correlation structure in the data that could be used to gain power, particularly when a Bonferroni correction is applied to adjust for multiple testing. In this article, we propose using regression techniques for misspecified multivariate outcomes to increase statistical power over independence-based modeling at each locus. Even when the outcome …


The Metallicity Distribution Of Intracluster Stars In Virgo, Benjamin F. Willaims, Ted Von Hippel, Et Al. Feb 2007

The Metallicity Distribution Of Intracluster Stars In Virgo, Benjamin F. Willaims, Ted Von Hippel, Et Al.

Publications

We have used the Hubble Space Telescope's Advanced Camera for Surveys (ACS) to detect and measure ~5300 stars in a single intracluster field in the Virgo Cluster. By performing F606W and F814W photometry on these stars, we have determined their metallicity distribution function and constrained the types of stars present in this portion of Virgo's intracluster space. Based on the small number of stars detected that were brighter than the red giant branch (RGB) tip, we suggest that in this region, Virgo's intracluster stars are mostly old (10 Gyr). Through analysis of the RGB stars themselves, we determine that …


Investigation Of A “Wall” Wave Event, Feng Li, Gary R. Swenson, Alan Z. Liu, Michael Taylor, Yucheng Zhao Feb 2007

Investigation Of A “Wall” Wave Event, Feng Li, Gary R. Swenson, Alan Z. Liu, Michael Taylor, Yucheng Zhao

Physical Sciences - Daytona Beach

A bright airglow event was observed at Maui, Hawaii, on the night of 11–12 August 2004 with multiple instruments including a Na wind/temperature lidar, an airglow imager, and a mesospheric temperature mapper. The characteristics of this event were investigated with measurements from these instruments. Analysis showed that this event was caused by a large-amplitude, upward-propagating gravity wave with a period of about 4–5 hours and a vertical wavelength of about 20 km, i.e., a “wall” wave. This wall wave induced dramatic changes in temperature (60 K), airglow intensity (doubled in the OH and tripled in the O2 emissions), and …


Photometry Of Type Ii Cepheid Candidates From The Rotse-I Demonstration Project, Edward G. Schmidt, Shawn Langan, Danielle Rogalla, Lauren Thacker-Lynn Feb 2007

Photometry Of Type Ii Cepheid Candidates From The Rotse-I Demonstration Project, Edward G. Schmidt, Shawn Langan, Danielle Rogalla, Lauren Thacker-Lynn

Edward Schmidt Publications

We have obtained VR photometry of 205 Cepheid variable star candidates that were discovered in a small section of the Northern Sky Variability Survey. Given their locations and apparent magnitudes, any stars in this sample that are Cepheids are very likely to be type II Cepheids. On the basis of the regularity of variation, revised periods, light-curve morphology, slope of the color-magnitude relation, and color, we have identified 97 probable Cepheids and 17 possible Cepheids. While some of the photometric properties, particularly the colors, are consistent with the identification of these stars as Cepheids, the amplitudes are small compared to …


Seasonal Changes In Allocation, Growth, And Photosynthetic Responses Of The Submersed Macrophyte Egeria Densa Planch. (Hydrocharitaceae) From Oregon And California, Toni Garrett Pennington Feb 2007

Seasonal Changes In Allocation, Growth, And Photosynthetic Responses Of The Submersed Macrophyte Egeria Densa Planch. (Hydrocharitaceae) From Oregon And California, Toni Garrett Pennington

Dissertations and Theses

Many rooted macrophytes form a dense canopy on the water surface that is detrimental to aquatic organisms, water quality, navigation, and recreation. Control of invasive macrophytes may be improved when management activities are linked to the plant's biology. The purpose of this research was to evaluate seasonal changes in the morphology, growth rates, allocation patterns and photosynthetic responses of a clonal submersed macrophyte. Egeria densa Planch. (Hydrocharitaceae) is highly invasive in the USA where it forms dense surface canopies in freshwater ecosystems. Using E. densa the following hypotheses were evaluated: (1) flowering stems have reduced capacity for vegetative growth as …


The Resolved Stellar Populations Of A Dwarf Spheroidal Galaxy In The Virgo Cluster, Patrick R. Durell, Ted Von Hippel, Et Al. Feb 2007

The Resolved Stellar Populations Of A Dwarf Spheroidal Galaxy In The Virgo Cluster, Patrick R. Durell, Ted Von Hippel, Et Al.

Publications

We report on the discovery of a faint (MV ~ -10.6 ± 0.2) dwarf spheroidal galaxy on deep F606W and F814W Hubble Space Telescope images of a Virgo intracluster field. The galaxy is easily resolved in our images, as our color magnitude diagram (CMD) extends 1 magnitude beyond the tip of the red giant branch (RGB). Thus, it is the deepest CMD for a small dwarf galaxy inside a cluster environment. Using the colors of the RGB stars, we derive a metal abundance for the dwarf of [M/H] = -2.3 ± 0.3 and show that the metallicity dispersion …


Quickest Flows Over Time, Lisa Fleischer, Martin Skutella Feb 2007

Quickest Flows Over Time, Lisa Fleischer, Martin Skutella

Dartmouth Scholarship

Flows over time (also called dynamic flows) generalize standard network flows by introducing an element of time. They naturally model problems where travel and transmission are not instantaneous. Traditionally, flows over time are solved in time‐expanded networks that contain one copy of the original network for each discrete time step. While this method makes available the whole algorithmic toolbox developed for static flows, its main and often fatal drawback is the enormous size of the time‐expanded network. We present several approaches for coping with this difficulty. First, inspired by the work of Ford and Fulkerson on maximal st …


High Energy Three-Body Breakup Of Three-Nucleon Systems, Tigran Abrahamyan Feb 2007

High Energy Three-Body Breakup Of Three-Nucleon Systems, Tigran Abrahamyan

FIU Electronic Theses and Dissertations

The main goal of this dissertation was to study two- and three-nucleon Short Range Correlations (SRCs) in high energy three-body breakup of 3He nucleus in 3He(e, e'NN)N reaction. SRCs are characterized by quantum fluctuations in nuclei during which constituent nucleons partially overlap with each other.

A theoretical framework is developed within the Generalized Eikonal Approximation (GEA) which upgrades existing medium-energy methods that are inapplicable for high momentum and energy transfer reactions. High momentum and energy transfer is required to provide sufficient resolution for probing SRCs. GEA is a covariant theory which is formulated through the effective Feynman …


Nondiffusive Spin Dynamics In A Two-Dimensional Electron Gas, Christopher P. Weber, J. Orenstein, B. Andrei Bernevig, Shou-Cheng Zhang, Jason Stephens, D. D. Awschalom Feb 2007

Nondiffusive Spin Dynamics In A Two-Dimensional Electron Gas, Christopher P. Weber, J. Orenstein, B. Andrei Bernevig, Shou-Cheng Zhang, Jason Stephens, D. D. Awschalom

Physics

We describe measurements of spin dynamics in the two-dimensional electron gas in GaAs=GaAlAs quantum wells. Optical techniques, including transient spin-grating spectroscopy, are used to probe the relaxation rates of spin polarization waves in the wave vector range from zero to 6 x 104 cm-1. We find that the spin polarization lifetime is maximal at a nonzero wave vector, in contrast with expectations based on ordinary spin diffusion, but in quantitative agreement with recent theories that treat diffusion in the presence of spin-orbit coupling


Analysis Using Smoothing Via Penalized Splines As Implemented In Lme() In R, John R. Howell Feb 2007

Analysis Using Smoothing Via Penalized Splines As Implemented In Lme() In R, John R. Howell

Theses and Dissertations

Spline smoothers as implemented in common mixed model software provide a familiar framework for estimating semi-parametric and non-parametric models. Following a review of literature on splines and mixed models, details for implementing mixed model splines are presented. The examples use an experiment in the health sciences to demonstrate how to use mixed models to generate the smoothers. The first example takes a simple one-group case, while the second example fits an expanded model using three groups simultaneously. The second example also demonstrates how to fit confidence bands to the three-group model. The examples use mixed model software as implemented in …


Determining Magmatic Processes From Analysis Of Phenocrysts And Gabbroic Xenoliths Contained In Calbuco Andesites, Tiffany Sperry Horst Feb 2007

Determining Magmatic Processes From Analysis Of Phenocrysts And Gabbroic Xenoliths Contained In Calbuco Andesites, Tiffany Sperry Horst

FIU Electronic Theses and Dissertations

Calbuco Volcano, in Southern Chile, has eruptive products of predominantly andesitic hornblende-bearing lava. A purpose of this work is to understand magmatic processes and how Calbuco magma chemistry is related to the explosive volcanic character. Calbuco lava has a mineral assemblage of plagioclase, hornblende, orthopyroxene, clinopyroxene, olivine, and magnetite and entrained gabbroic xenoliths with the same mineral assemblage. The presence of hornblende is evidence for dissolved water in the magma. Detailed petrographic/textural analysis has been done using petrographic microscopy and back-scattered electron imaging (BSE); geochemical analysis by electron microprobe (EPMA). Major findings include 1) that hornblende and hornblende-bearing gabbroic cumulates …