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2006

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Modeling, Analysis, And Experimental Study Of In Vivo Wheeled Robotic Mobility, Mark E. Rentschler, Jason Dumpert, Stephen R. Platt, Karl Iagnemma, Dmitry Oleynikov, Shane M. Farritor Jan 2006

Modeling, Analysis, And Experimental Study Of In Vivo Wheeled Robotic Mobility, Mark E. Rentschler, Jason Dumpert, Stephen R. Platt, Karl Iagnemma, Dmitry Oleynikov, Shane M. Farritor

Department of Mechanical and Materials Engineering: Faculty Publications

Laparoscopy is abdominal surgery performed with long tools inserted through small incisions. The use of small incisions reduces patient trauma, but also eliminates the surgeon’s ability to view and touch the surgical environment directly. These limitations generally restrict the application of laparoscopy to procedures less complex than those performed during open surgery. This paper presents a theoretical and experimental analysis of miniature, wheeled, in vivo robots to support laparoscopy. The objective is to develop a wireless mobile imaging robot that can be placed inside the abdominal cavity during surgery. Such robots will allow the surgeon to view the surgical environment …

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Sentinel Nematodes Of Land-Use Change And Restoration In Tallgrass Prairie, T. C. Todd, T. O. Powers, P.G. Mullin Jan 2006

Sentinel Nematodes Of Land-Use Change And Restoration In Tallgrass Prairie, T. C. Todd, T. O. Powers, P.G. Mullin

Department of Plant Pathology: Faculty Publications

Changes in land use and the associated changes in land cover are recognized as the most important component of human-induced global change. Much attention has been focused on deforestation, but grasslands are among the most endangered ecosystems on Earth. The North American tallgrass prairie is a dramatic example, exhibiting a greater than 95% decline in historical area. Renewed interest in prairie conservation and restoration has highlighted the need for ecological indicators of disturbance and recovery in native systems, including the below ground component. The tallgrass prairie differs from the agricultural systems that have replaced it in having greater diversity and …

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A Position Paper On The Electronic Publication Of Nematode Taxonomic Manuscripts, Eyualem Abebe, James G. Baldwin, Byron Adams, Duane Hope, Scott Gardner, Robin Huettel, Peter Mullin, Thomas O. Powers, Jyotsna Sharma, Weimin Ye, William K. Thomas Jan 2006

A Position Paper On The Electronic Publication Of Nematode Taxonomic Manuscripts, Eyualem Abebe, James G. Baldwin, Byron Adams, Duane Hope, Scott Gardner, Robin Huettel, Peter Mullin, Thomas O. Powers, Jyotsna Sharma, Weimin Ye, William K. Thomas

Department of Plant Pathology: Faculty Publications

Several nematode species have now attained ‘model organism’ status, yet there remain many niches in basic biological inquiry for which nematodes would be ideal model systems of study. However, furthering the model system approach is hindered by lack of information on nematode biodiversity. The shortage of taxonomic resources to inventory and characterize biodiversity hinders research programs in invasion biology, ecosystem functioning, conservation biology, and many others. The disproportion between numbers of species to be described and numbers of available taxonomic specialists is greater for Nematoda than for any other metazoan phylum. A partial solution to the taxonomic impediment is the …

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Interactions Between The Soybean Cyst Nematode And Fusarium Solani F. Sp. Glycines Based On Greenhouse Factorial Experiments, X. Gao, T. A. Jackson, G. L. Hartman, T. L. Niblack Jan 2006

Interactions Between The Soybean Cyst Nematode And Fusarium Solani F. Sp. Glycines Based On Greenhouse Factorial Experiments, X. Gao, T. A. Jackson, G. L. Hartman, T. L. Niblack

Department of Plant Pathology: Faculty Publications

The soybean cyst nematode, Heterodera glycines, and the fungus that causes sudden death syndrome (SDS) of soybean, Fusarium solani f. sp. glycines, frequently co-infest soybean (Glycine max) fields. The interactions between H. glycines and F. solani f. sp. glycines were investigated in factorial greenhouse experiments with different inoculum levels of both organisms on a soybean cultivar susceptible to both pathogens. Measured responses included root and shoot dry weights, H. glycines reproduction, area under the SDS disease progress curve, and fungal colonization of roots. Both H. glycines and F. solani f. sp. glycines reduced the growth of …

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First Report Of Leaf Spot Of Smooth Bromegrass Caused By Pithomyces Chartarum In Nebraska, C. Eken, C. C. Jochum, G. Y. Yuen Jan 2006

First Report Of Leaf Spot Of Smooth Bromegrass Caused By Pithomyces Chartarum In Nebraska, C. Eken, C. C. Jochum, G. Y. Yuen

Department of Plant Pathology: Faculty Publications

Smooth bromegrass (Bromus inermis Leyss.) is the most common perennial grass species cultivated for forage in North America. During late fall of 2004, smooth bromegrass plants in Lincoln, NE were observed to have brown lesions on leaf midveins that were several centimeters long. Symptomatic leaves were surface disinfested for 1 min in 2% NaOCl and incubated at 25°C on potato dextrose agar (PDA) and water agar. The fungus, Pithomyces chartarum (Berk. & Curt) Ellis, was isolated consistently and identified on the basis of morphological characteristics (1). Colonies were effused and black on PDA. Conidiophores measured 3.5 to 8 …

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Bioinformatics-Enabled Identification Of The Hrpl Regulon And Type Iii Secretion System Effector Proteins Of Pseudomonas Syringae Pv. Phaseolicola 1448a, Monica Vencato, Fang Tian, James R. Alfano, C. Robin Buell, Samuel Cartinhour, Genevieve A. Declerck, David S. Guttman, John Stavrinides, Vinita Joardar, Magdalen Lindeberg, Philip A. Bronstein, John W. Mansfield, Christopher R. Myers, Alan Collmer, David J. Schneider Jan 2006

Bioinformatics-Enabled Identification Of The Hrpl Regulon And Type Iii Secretion System Effector Proteins Of Pseudomonas Syringae Pv. Phaseolicola 1448a, Monica Vencato, Fang Tian, James R. Alfano, C. Robin Buell, Samuel Cartinhour, Genevieve A. Declerck, David S. Guttman, John Stavrinides, Vinita Joardar, Magdalen Lindeberg, Philip A. Bronstein, John W. Mansfield, Christopher R. Myers, Alan Collmer, David J. Schneider

Department of Plant Pathology: Faculty Publications

The ability of Pseudomonas syringae pv. phaseolicola to cause halo blight of bean is dependent on its ability to translocate effector proteins into host cells via the hypersensitive response and pathogenicity (Hrp) type III secretion system (T3SS). To identify genes encoding type III effectors and other potential virulence factors that are regulated by the HrpL alternative sigma factor, we used a hidden Markov model, weight matrix model, and type III targeting-associated patterns to search the genome of P. syringae pv. phaseolicola 1448A, which recently was sequenced to completion. We identified 44 high-probability putative Hrp promoters upstream of genes encoding the …

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Regulation Of Hyphal Morphogenesis And The Dna Damage Response By The Aspergillus Nidulans Atm Homolog Atma, Iran Malavazi, Camile P. Semighini, Marcia Regina Von Zeska Kress, Steven D. Harris, Gustavo H. Goldman Jan 2006

Regulation Of Hyphal Morphogenesis And The Dna Damage Response By The Aspergillus Nidulans Atm Homolog Atma, Iran Malavazi, Camile P. Semighini, Marcia Regina Von Zeska Kress, Steven D. Harris, Gustavo H. Goldman

Department of Plant Pathology: Faculty Publications

Ataxia telangiectasia (A-T) is an inherited disorder characterized by progressive loss of motor function and susceptibility to cancer. The most prominent clinical feature observed in A-T patients is the degeneration of Purkinje motor neurons. Numerous studies have emphasized the role of the affected gene product, ATM, in the regulation of the DNA damage response. However, in Purkinje cells, the bulk of ATM localizes to the cytoplasm and may play a role in vesicle trafficking. The nature of this function, and its involvement in the pathology underlying A-T, remain unknown. Here we characterize the homolog of ATM (AtmA) in the filamentous …

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Characterization Of Hiv-1 Subtype C Envelope Glycoproteins From Perinatally Infected Children With Different Courses Of Disease, Hong Zhang, Federico Hoffmann, Jun He, Xiang He, Chipepo Kankasa, John T. West, Charles D. Mitchell, Ruth M. Ruprecht, Guillermo Orti, Charles Wood Jan 2006

Characterization Of Hiv-1 Subtype C Envelope Glycoproteins From Perinatally Infected Children With Different Courses Of Disease, Hong Zhang, Federico Hoffmann, Jun He, Xiang He, Chipepo Kankasa, John T. West, Charles D. Mitchell, Ruth M. Ruprecht, Guillermo Orti, Charles Wood

Nebraska Center for Virology: Faculty Publications

Background: The causal mechanisms of differential disease progression in HIV-1 infected children remain poorly defined, and much of the accumulated knowledge comes from studies of subtype B infected individuals. The applicability of such findings to other subtypes, such as subtype C, remains to be substantiated. In this study, we longitudinally characterized the evolution of the Env V1–V5 region from seven subtype C HIV-1 perinatally infected children with different clinical outcomes. We investigated the possible influence of viral genotype and humoral immune response on disease progression in infants.

Results: Genetic analyses revealed that rapid progressors (infants that died in the first …

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Or.76. Myelin Specific Regulatory T-Cells Expand From Naturally Occurring Regulatory T-Cells And Accumulate In The Cns During Eae [Abstract Only], Thomas Korn, Jay Reddy, Wenda Gao, Terry Strom, Mohamed Oukka, Vijay K. Kuchroo Jan 2006

Or.76. Myelin Specific Regulatory T-Cells Expand From Naturally Occurring Regulatory T-Cells And Accumulate In The Cns During Eae [Abstract Only], Thomas Korn, Jay Reddy, Wenda Gao, Terry Strom, Mohamed Oukka, Vijay K. Kuchroo

Jay Reddy Publications

FoxP3 is a lineage specific marker for regulatory T-cells (Treg). We have generated FoxP3 knock-in (KI) mice by introducing a bicistronic GFP reporter into the endogenous FoxP3 locus, allowing us to faithfully track T-reg in vivo. Recently, we have also generated a MOG 35-55/IAb-tetramer. The combination of these two technologies enables us to study the in vivo behavior of myelin specific T-reg and effector T-cells (T-eff) during EAE. Upon immunization with MOG 35-55, we identified a population of MOG-tetramerreactive T-reg in the peripheral lymphoid compartment. T-reg trafficked to the CNS where they were readily detected as early as day 10 …

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Or.107. Tim-1 Plays A Crucial Role In The Expansion Of Autopathogneic T-Cells And Regulation Of Autoimmunity [Abstract Only], Sheng Xioa, Nader Najafian, Jay Reddy, Monica Albin, Chen Zhu, Ana Anderson, Zheng Zhang, Cristina Gutierrez, Raymond Sobel, Dale Umetsu, Hideo Yagita, Hisaya Akiba, Mohamed Sayegh, Rosemarie Dekruyff, Vijay K. Kuchroo Jan 2006

Or.107. Tim-1 Plays A Crucial Role In The Expansion Of Autopathogneic T-Cells And Regulation Of Autoimmunity [Abstract Only], Sheng Xioa, Nader Najafian, Jay Reddy, Monica Albin, Chen Zhu, Ana Anderson, Zheng Zhang, Cristina Gutierrez, Raymond Sobel, Dale Umetsu, Hideo Yagita, Hisaya Akiba, Mohamed Sayegh, Rosemarie Dekruyff, Vijay K. Kuchroo

Jay Reddy Publications

T-cell immunoglobulin and mucin (TIM) family Members are differentially expressed on Th1 and Th2 cells. Polymorphisms of TIM-1 have been associated with susceptibility to asthma; however, its role in regulating autoimmunity has not been studied. Here, we have used an agonistic antiTIM-1 antibody (Ab, Clone 3B3) which has previously been shown to costimulate T-cell activation and expansion, to analyze the role of TIM-1 in the development and regulation of experimental autoimmune encephalomyelitis (EAE). Treatment with 3B3 dramatically enhances the severity of EAE as well as the frequency of encephalitogenic CD4+ T-cells and the production of IFN-g and IL-17 by these …

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Structure And Magnetism Of Atomically Thin Fe Layers On Flat And Vicinal Pt Surfaces, D. Repetto, T. Y. Lee, S. Rusponi, Jan Honolka, K. Kuhnke, Violetta Sessi, Ulrich Starke, H. Brune, P. Gambardella, C. Carbone, Axel Enders, K. Kern Jan 2006

Structure And Magnetism Of Atomically Thin Fe Layers On Flat And Vicinal Pt Surfaces, D. Repetto, T. Y. Lee, S. Rusponi, Jan Honolka, K. Kuhnke, Violetta Sessi, Ulrich Starke, H. Brune, P. Gambardella, C. Carbone, Axel Enders, K. Kern

Axel Enders Publications

Ultrathin Fe films on Pt substrates have been investigated under ultrahigh vacuum conditions by scanning tunneling microscopy, low energy electron diffraction, magneto-optical Kerr effect, x-ray magnetic circular dichroism measurements, and Kerr microscopy. We present a comparison between Fe films on flat Pt(111) and stepped Pt(997), with particular focus on the magnetic anisotropy in the submonolayer thickness range below 0.2 monolayer coverage, and above the spin reorientation transition at 3 monolayer thickness. The comparison of structure and magnetism suggests that the perpendicular easy axis found for films thinner than three monolayers is due to dominating contributions from both film interfaces to …

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The Electronic Structure And Band Hybridization Of Co/Ti Doped Bafe12O19, Natalie Palina, H. Modrow, R. Müller, J. Hormes, Peter A. Dowben, Yaroslav B. Losovyj Jan 2006

The Electronic Structure And Band Hybridization Of Co/Ti Doped Bafe12O19, Natalie Palina, H. Modrow, R. Müller, J. Hormes, Peter A. Dowben, Yaroslav B. Losovyj

Department of Physics and Astronomy: Faculty Publications

We identify contributions to the valence band of the nanosized BaFe12−2xCoxTixO19 barium ferrite particles, from the cobalt and titanium dopants. Resonant photoemission results show that cobalt and titanium dopants strongly hybridize with the barium ferrite matrix. Fano resonances are identified in the valence band region, at the Ba (5s), Ti (3p) and Co (3p) thresholds, and there are significant contributions to the density of states, residing within 2 eV of the Fermi level, from barium and/or iron.

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A Three-Grating Electron Interferometer, G. Gronniger, Brett E. Barwick, Herman Batelaan Jan 2006

A Three-Grating Electron Interferometer, G. Gronniger, Brett E. Barwick, Herman Batelaan

Department of Physics and Astronomy: Faculty Publications

We report the observation of fringes from a three-grating electron interferometer. Interference fringes have been observed at low energies ranging from 6 to 10 keV. Contrasts of up to 25% are recorded and exceed the maximal contrast of the classical equivalent Moiré deflectometer. This type of interferometer could serve as a separate beam Mach–Zehnder interferometer for low-energy electron interferometry experiments.

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Inclusive Jet Cross Section Measurement At Dø, M. Voutilainen Jan 2006

Inclusive Jet Cross Section Measurement At Dø, M. Voutilainen

Department of Physics and Astronomy: Faculty Publications

We present a new preliminary measurement of the inclusive jet cross section in pp collisions based on a integrated luminosity of about 0.8 fb-1. The data were acquired using the DØ detector between 2002 and 2005. Jets are reconstructed using an iterative cone algorithm with radius Rcone = 0:7. The inclusive jet cross section is presented as a function of transverse jet momentum and rapidity. Predictions from perturbative QCD in next-to-leading order, plus threshold corrections in 2-loop accuracy describe the shape in the transverse jet momentum.

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Ferromagnetism And Structure Of Epitaxial Cr-Doped Anatase Tio2 Thin Films, T. C. Kaspar, T. Droubay, V. Shutthanandan, S. M. Heald, C. M. Wang, D. E. Mccready, S. Thevuthasan, J. D. Bryan, D. R. Gamelin, A. J. Kellock, M. F. Toney, X. Hong, C. H. Ahn, S. A. Chambers Jan 2006

Ferromagnetism And Structure Of Epitaxial Cr-Doped Anatase Tio2 Thin Films, T. C. Kaspar, T. Droubay, V. Shutthanandan, S. M. Heald, C. M. Wang, D. E. Mccready, S. Thevuthasan, J. D. Bryan, D. R. Gamelin, A. J. Kellock, M. F. Toney, X. Hong, C. H. Ahn, S. A. Chambers

Xia Hong Publications

The materials and magnetic properties of Cr-doped anatase TiO2 thin films deposited on LaAlO3(001) and SrTiO3(001) substrates by oxygen-plasma-assisted molecular beam epitaxy have been studied in detail to elucidate the origin of ferromagnetic ordering. Cr substitution for Ti in the anatase lattice, with no evidence of Cr interstitials, segregation, or secondary phases, was independently confirmed by transmission electron microscopy with energy dispersive x-ray spectroscopy, extended x-ray absorption fine structure, and Rutherford backscattering spectrometry in the channeling geometry. Epitaxial films deposited at ~0.1 Å/ s were found to have a highly defected crystalline structure, as quantified …

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Effect Of Electric Field Doping On The Anisotropic Magnetoresistance In Doped Manganites, X. Hong, J.-B. Yau, J. D. Hoffman, C. H. Ahn Jan 2006

Effect Of Electric Field Doping On The Anisotropic Magnetoresistance In Doped Manganites, X. Hong, J.-B. Yau, J. D. Hoffman, C. H. Ahn

Xia Hong Publications

We have modulated the anisotropic magnetoresistance (AMR) in 3–4 nm manganite films using the ferroelectric field effect—a method that electrostatically varies the carrier density without affecting the lattice distortion. While significant changes have been induced in TC and p, the AMR ratio remains the same when the magnetic state is not changed. This scaling behavior is in striking contrast to chemical doping results, where similar modulation of the carrier concentration (~0.1/Mn) changes the AMR ratio by ≥30%. The results reveal unambiguously the dominant role of chemical distortion in determining the AMR in manganites.

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Regional Patterns In The Isotopic Composition Of Natural And Anthropogenic Nitrate In Groundwater, High Plains, U.S.A., P. B. Mcmahon, J. K. Bohlke Jan 2006

Regional Patterns In The Isotopic Composition Of Natural And Anthropogenic Nitrate In Groundwater, High Plains, U.S.A., P. B. Mcmahon, J. K. Bohlke

United States Geological Survey: Staff Publications

Mobilization of natural nitrate (NO3-) deposits in the subsoil by irrigation water in arid and semiarid regions has the potential to produce large groundwater NO3- concentrations. The use of isotopes to distinguish between natural and anthropogenic NO3- sources in these settings could be complicated by the wide range in δ15N values of natural NO3-. An ~10 000 year record of paleore-charge from the regionally extensive High Plains aquifer indicates that δ15N values for NO3- derived from natural sources ranged from 1.3 to 12.3‰ and …

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Effect Of Method Of Delivering Nicarbazin To Mallards On Plasma 4,4′-Dinitrocarbanilide Levels And Reproduction, C. A. Yoder, J. K. Graham, L. A. Miller, K. S. Bynum, J. J. Johnston, M. J. Goodall Jan 2006

Effect Of Method Of Delivering Nicarbazin To Mallards On Plasma 4,4′-Dinitrocarbanilide Levels And Reproduction, C. A. Yoder, J. K. Graham, L. A. Miller, K. S. Bynum, J. J. Johnston, M. J. Goodall

United States Department of Agriculture Wildlife Services: Staff Publications

Nicarbazin (NCZ), a coccidiostat used in the poultry industry, has been developed as a contraceptive for resident Canada geese. We tested the efficacy of NCZ as a contraceptive using mallards (Anas platyrhynchos) as a model for Canada geese. Nicarbazin-treated corn was fed ad libitum for 14 d at 0, 750, 1,000, or 1,500 ppm. Plasma and egg levels of 4,4′-dinitrocarbanilide (DNC), the active anticoccidial component of NCZ, differed among treatment groups in a dose-response relationship, but plasma levels did not differ between sexes. Nicarbazin caused a decrease in egg weight, but there was no effect of NCZ on …

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Evaluation Of Nicarbazin As A Potential Waterfowl Contraceptive Using Mallards As A Model, C. A. Yoder, J. K. Graham, L. A. Miller, K. S. Bynum, J. J. Johnston, M. J. Goodall Jan 2006

Evaluation Of Nicarbazin As A Potential Waterfowl Contraceptive Using Mallards As A Model, C. A. Yoder, J. K. Graham, L. A. Miller, K. S. Bynum, J. J. Johnston, M. J. Goodall

United States Department of Agriculture Wildlife Services: Staff Publications

Contraception may provide a useful nonlethal management tool to reduce wild bird populations. We tested the efficacy of nicarbazin (NCZ) as a contraceptive for waterfowl and assessed health effects of NCZ, using domestic mallards (Anas platyrhynchos) as a model for Canada geese (Branta canadensis). Mallards were given gelatin capsules containing 0, 8.5, 17.0, or 33.75 mg of NCZ/kg of BW perorally once daily for 14 d. Fecal 4,4′- dinitrocarbanilide (DNC) and fluorescein were evaluated as potential markers of plasma and egg DNC levels. Plasma, egg, and fecal DNC levels differed among treatment groups in a dose …

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Molecular Effects Of Nicarbazin On Avian Reproduction, C. A. Yoder, J. K. Graham, L. A. Miller Jan 2006

Molecular Effects Of Nicarbazin On Avian Reproduction, C. A. Yoder, J. K. Graham, L. A. Miller

United States Department of Agriculture Wildlife Services: Staff Publications

Nicarbazin (NCZ) is an anticoccidial drug routinely used in the poultry industry that can negatively affect reproduction by reducing egg production, egg weight, and egg hatchability. The molecular mechanisms by which NCZ affects reproduction are unknown. Lipoprotein lipase, vitellogenin, transglutaminase, and calcium are all involved in egg formation and embryogenesis. Therefore, in vitro assays were used to evaluate 4 potential mechanisms of action of NCZ on egg formation and embryogenesis. First, a lipoprotein lipase assay was conducted to determine if NCZ increases lipoprotein lipase activity. Second, vitellogenin phosphorylation was evaluated to determine if NCZ acts as a vitellogenin phosphatase. Third, …

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Anthropogenic Drivers Of Ecosystem Change: An Overview, Gerald C. Nelson, Elena Bennett, Asmeret A. Berhe, Kenneth G. Cassman, Ruth Defries, Thomas Dietz, Achim R. Dobermann, Andrew Dobson, Anthony Janetos, Marc Levy, Diana Marco, Nebojsa Nakicenovic, Brian O'Neill, Richard Norgaard, Gerhard Petschel-Held, Dennis Ojima, Prabhu Pingali, Robert Watson, Monika Zurek Jan 2006

Anthropogenic Drivers Of Ecosystem Change: An Overview, Gerald C. Nelson, Elena Bennett, Asmeret A. Berhe, Kenneth G. Cassman, Ruth Defries, Thomas Dietz, Achim R. Dobermann, Andrew Dobson, Anthony Janetos, Marc Levy, Diana Marco, Nebojsa Nakicenovic, Brian O'Neill, Richard Norgaard, Gerhard Petschel-Held, Dennis Ojima, Prabhu Pingali, Robert Watson, Monika Zurek

Department of Agronomy and Horticulture: Faculty Publications

This paper provides an overview of what the Millennium Ecosystem Assessment (MA) calls “indirect and direct drivers” of change in ecosystem services at a global level. The MA definition of a driver is any natural or human-induced factor that directly or indirectly causes a change in an ecosystem. A direct driver unequivocally influences ecosystem processes. An indirect driver operates more diffusely by altering one or more direct drivers. Global driving forces are categorized as demographic, economic, sociopolitical, cultural and religious, scientific and technological, and physical and biological. Drivers in all categories other than physical and biological are considered indirect. Important …

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Performance Of Weedsoft For Predicting Soybean Yield Loss, Shawn M. Hock, Stevan Z. Knezevic, Alex Martin, John L. Lindquist Jan 2006

Performance Of Weedsoft For Predicting Soybean Yield Loss, Shawn M. Hock, Stevan Z. Knezevic, Alex Martin, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Decision support systems (DSSs) have been developed to assist producers and consultants with weed management decisions. WeedSOFT is a DSS currently used in several states in the northcentral region of the United States. Accurate estimates of crop yield loss due to weed interference are required for cost-effective weed management recommendations. WeedSOFT uses competitive indices (CIs) to predict crop yield loss under multiple weed species, weed densities, and relative times of weed emergence. Performance of several WeedSOFT versions to predict soybean yield loss from weed competition was evaluated using CI values in WeedSOFT version 9.0 compared to new CI values calculated …

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Predicting Biomass Partitioning To Root Versus Shoot In Corn And Velvetleaf (Abutilon Theophrasti), Kimberly D. Bonifas, John L. Lindquist Jan 2006

Predicting Biomass Partitioning To Root Versus Shoot In Corn And Velvetleaf (Abutilon Theophrasti), Kimberly D. Bonifas, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Knowledge of how plants will partition their new biomass will aid in understanding competition between crops and weeds. This study determined if the amount of biomass partitioned to the root versus the shoot can be predicted from tissue carbon [C] and nitrogen [N] concentrations and the daily gain in C (GC) and N (GN) for each unit shoot and root biomass, respectively. Pots measuring 28 cm diameter and 60 cm deep were embedded in the ground, and each contained one plant of either corn or velvetleaf. Each plant received one of three nitrogen treatments: 0, 1, …

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Early-Season Insect Defoliation Influences The Critical Time For Weed Removal In Soybean, Travis C. Gustafson, Stevan Z. Knezevic, Thomas E. Hunt, John L. Lindquist Jan 2006

Early-Season Insect Defoliation Influences The Critical Time For Weed Removal In Soybean, Travis C. Gustafson, Stevan Z. Knezevic, Thomas E. Hunt, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

To develop more effective pest-management strategies, it is essential to understand how different pests interact with each other and the crop. Field studies were conducted in 2003 and 2004 at two Nebraska locations to determine the effects of early-season crop defoliation on the critical time for weed removal (CTWR) in narrow-row soybean. Three soybean defoliation levels were selected to simulate 0, 30, and 60% leaf tissue removal by the bean leaf beetle. Weeds were allowed to compete with the crop until V2, V4, V6, R3, and R5 growth stages. There were also season-long weedy and weed-free treatments. Results indicated that …

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Effect Of Nitrogen Addition On The Comparative Productivity Of Corn And Velvetleaf (Abutilon Theophrasti), Darren C. Barker, Stevan Z. Knezevic, Alex R. Martin, Daniel T. Walters, John L. Lindquist Jan 2006

Effect Of Nitrogen Addition On The Comparative Productivity Of Corn And Velvetleaf (Abutilon Theophrasti), Darren C. Barker, Stevan Z. Knezevic, Alex R. Martin, Daniel T. Walters, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Weeds that respond more to nitrogen fertilizer than crops may be more competitive under high nitrogen (N) conditions. Therefore, understanding the effects of nitrogen on crop and weed growth and competition is critical. Field experiments were conducted at two locations in 1999 and 2000 to determine the influence of varying levels of N addition on corn and velvetleaf height, leaf area, biomass accumulation, and yield. Nitrogen addition increased corn and velvetleaf height by a maximum of 15 and 68%, respectively. N addition increased corn and velvetleaf maximum leaf area index (LAI) by up to 51 and 90%. Corn and velvetleaf …

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Plant Breeding Training In The U.S., P. Stephen Baenziger Jan 2006

Plant Breeding Training In The U.S., P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

The plant breeding enterprise is large and highly interdisciplinary. In considering how to approach this topic, it is necessary to define who is a plant breeder for that defines the scope of this paper. For the purpose of this paper, a plant breeder will be defined as a person who is actively involved in creating new plant germplasm that may lead to new cultivars or be used as parents to create new cultivars of food, feed, fiber, and ornamental plants. This definition is deliberately narrow. For example it does not include those who are developing molecular markers for marker assisted …

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Soybean Cultivars Resulted From More Recombination Events Than Unselected Lines In The Same Population, T. R. Stefaniak, D. L. Hyten Jr., V. R. Pantalone, A. Klarer, T. W. Pfeiffer Jan 2006

Soybean Cultivars Resulted From More Recombination Events Than Unselected Lines In The Same Population, T. R. Stefaniak, D. L. Hyten Jr., V. R. Pantalone, A. Klarer, T. W. Pfeiffer

Department of Agronomy and Horticulture: Faculty Publications

The selection of superior adapted cultivars has contributed to the doubling of soybean [Glycine max (L.) Merr.] yields in the USA since 1930. Genetic variation was required for this selection to be effective. The objective of this study was to evaluate the importance of homologous chromosome meiotic recombination in the creation of soybean cultivars. A set of 10 adapted high-yielding cultivars selected from the cross ‘Williams’ × ‘Essex’ was com-pared with a set of 156 random recombinant inbred lines (RILs) from the same population. Crossover events were identified using 143 simple sequence repeat (SSR) markers span-ning all 20 soybean …

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Impacts Of Genetic Bottlenecks On Soybean Genome Diversity, D. L. Hyten, Qijian Song, Youlin Zhu, Ik-Young Choi, Randall L. Nelson, Jose M. Costa, James E. Specht, Randy C. Shoemaker, Perry B. Cregan Jan 2006

Impacts Of Genetic Bottlenecks On Soybean Genome Diversity, D. L. Hyten, Qijian Song, Youlin Zhu, Ik-Young Choi, Randall L. Nelson, Jose M. Costa, James E. Specht, Randy C. Shoemaker, Perry B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

Soybean has undergone several genetic bottlenecks. These include domestication in Asia to produce numerous Asian landraces, introduction of relatively few landraces to North America, and then selective breeding over the past 75 years. It is presumed that these three human-mediated events have reduced genetic diversity. We sequenced 111 fragments from 102 genes in four soybean populations representing the populations before and after genetic bottlenecks. We show that soybean has lost many rare sequence variants and has undergone numerous allele frequency changes throughout its history. Although soybean genetic diversity has been eroded by human selection after domestication, it is notable that …

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Ethylene Could Influence Ferric Reductase, Iron Transporter, And H+-Atpase Gene Expression By Affecting Fer (Or Fer-Like) Gene Activity, Carlos Lucera, Brian M. Waters, Francisco Javier Romera, María José García, María Morales, Esteban Alcántara, Rafael Pérez-Vicente Jan 2006

Ethylene Could Influence Ferric Reductase, Iron Transporter, And H+-Atpase Gene Expression By Affecting Fer (Or Fer-Like) Gene Activity, Carlos Lucera, Brian M. Waters, Francisco Javier Romera, María José García, María Morales, Esteban Alcántara, Rafael Pérez-Vicente

Department of Agronomy and Horticulture: Faculty Publications

In previous works, it has been shown, by using ethylene inhibitors and precursors, that ethylene could participate in the regulation of the enhanced ferric reductase activity of Fe-deficient Strategy I plants. However, it was not known whether ethylene regulates the ferric reductase gene expression or other aspects related to this activity. This paper is a study of the effects of ethylene inhibitors and precursors on the expression of the genes encoding the ferric reductases and iron transporters of Arabidopsis thaliana (FRO2 and IRT1) and Lycopersicon esculentum (= Solanum lycopersicum) (FRO1 and IRT1) plants. The effects …

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Circular Ultrasound Compounding By Designed Matrix Weighting, Gregory Bashford, Jonathan Morse Jan 2006

Circular Ultrasound Compounding By Designed Matrix Weighting, Gregory Bashford, Jonathan Morse

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Spatial compounding is an imaging technique that aims to improve image contrast by combining partially decorrelated images acquired at different angles or positions. In conventional spatial compounding, data sets are combined with equal weighting. Here, we describe an alternative method of reconstruction using algorithms which weight the data based on a “quality” matrix. The quality matrix is derived from beam-forming characteristics. For each data set, the reliability of the data is assumed to vary spatially. By compounding the data based on the quality matrix, a complete image is formed. Here, we describe the construction of a rotational translation stage and …

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