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Iowa State University

1997

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Further Characterization Of A Complement-Sensitive Mutant Of A Virulent Avian Escherichia Coli Isolate, Theodore J. Kottom, Lisa K. Nolan, Michael Robinson, John Brown, Tom Gustad, Shelley M. Horne, Catherine W. Giddings Dec 1997

Further Characterization Of A Complement-Sensitive Mutant Of A Virulent Avian Escherichia Coli Isolate, Theodore J. Kottom, Lisa K. Nolan, Michael Robinson, John Brown, Tom Gustad, Shelley M. Horne, Catherine W. Giddings

Lisa K. Nolan

An attempt was made to characterize the mechanism of complement resistance operating in a virulent avian Escherichia coli isolate. Using flow cytometry to detect antibody to C3, we found that there was significantly more antibody bound to a complement-sensitive mutant of this wild type than to the parent organism, suggesting that more C3 subunits were bound to the wild type. Neither the wild type nor the mutant degraded C3. Further, the mutant was phagocytosed to a significantly greater degree than the wild type by cultured phagocytes in the presence of C5-deficient serum. These data suggest that the wild type is ...


A Highly Adherent Phenotype Associated With Virulent Bvg+-Phase Swine Isolates Of Bordetella Bronchiseptica Grown Under Modulating Conditions, Karen B. Register, Mark R. Ackermann Dec 1997

A Highly Adherent Phenotype Associated With Virulent Bvg+-Phase Swine Isolates Of Bordetella Bronchiseptica Grown Under Modulating Conditions, Karen B. Register, Mark R. Ackermann

Mark R. Ackermann

The ability of Bvg(-)-phase and Bvg(+)-phase Bordetella bronchiseptica swine isolates, grown under modulating or nonmodulating conditions, to adhere to swine ciliated nasal epithelial cells was determined. When virulent strains were cultivated at 37 degrees C in the Bvg+ phase, numerous adherent bacteria (approximately eight per cell, depending on the strain used) were observed. However, when such strains were grown under modulating conditions (23 degrees C), a significant increase in the level of attachment was seen, suggesting that B. bronchiseptica produces a Bvg-repressed adhesin under these conditions. bvg mutant strains, including an isogenic bvgS mutant, adhered minimally. Western blots ...


Hydrodynamics Of Dispersed Liquid Droplets In Agitated Synthetic Fibrous Slurries, Theodore J. Heindel, Feler Bose, S. Mostafa Ghiaasiaan Nov 1997

Hydrodynamics Of Dispersed Liquid Droplets In Agitated Synthetic Fibrous Slurries, Theodore J. Heindel, Feler Bose, S. Mostafa Ghiaasiaan

Theodore J. Heindel

The hydrodynamic and liquid particle dispersion processes in agitated vessels containing dilute liquid−liquid dispersions, and dilute liquid dispersions in synthetic fibrous slurries, were experimentally studied. A transparent cylindrical vessel 25 cm in height and 15.5 cm in diameter equipped with a six-blade impeller, with geometric proportions representing the standard vessel configuration, was used. The steady-state size distributions of molten wax particles, which constituted 1% by weight of the mixture everywhere, in pure water, and in aqueous slurries with 0.1%, 0.5%, 0.8%, and 1.0% consistencies of nylon fibers, were measured using sampling and microscopic image ...


Structure Factors And Their Distributions In Driven Two-Species Models, G. Korniss, Beate Schmittmann Oct 1997

Structure Factors And Their Distributions In Driven Two-Species Models, G. Korniss, Beate Schmittmann

Beate Schmittmann

We study spatial correlations and structure factors in a three-state stochastic lattice gas, consisting of holes and two oppositely “charged” species of particles, subject to an “electric” field at zero total charge. The dynamics consists of two nearest-neighbor exchange processes, occurring on different times scales, namely, particle-hole and particle-particle exchanges. Using both Langevin equations and Monte Carlo simulations, we study the steady-state structure factors and correlation functions in the disordered phase, where density profiles are homogeneous. In contrast to equilibrium systems, the average structure factors here show a discontinuity singularity at the origin. The associated spatial correlation functions exhibit intricate ...


Women, Technology, And Rural Life: Some Recent Literature, Pamela Riney-Kehrberg Oct 1997

Women, Technology, And Rural Life: Some Recent Literature, Pamela Riney-Kehrberg

Pamela Riney-Kehrberg

Historical study of American farm women has had a relatively short life, reaching back approximately twenty years. Rural women rarely existed in earlier scholarship that reserved the categories of farmer and farming for males. Agricultural history thus manifested itself as a story of men and their tools, stretching back historiographically into the early days of the 20th century. Although in 1953 Jared van Wagenen described in careful detail many of the physical processes of farming in The Golden Age of Homespun, the women's work from which he derived his title occupied less than twenty pages at the end of ...


Iron Regulatory Protein 1 Is Not Required For The Modulation Of Ferritin And Transferrin Receptor Expression By Iron In A Murine Pro-B Lymphocyte Cell Line, Kevin Schalinske, Kenneth P. Blemings, Daniel W. Steffen, Opal S. Chen, Richard S. Eisenstein Sep 1997

Iron Regulatory Protein 1 Is Not Required For The Modulation Of Ferritin And Transferrin Receptor Expression By Iron In A Murine Pro-B Lymphocyte Cell Line, Kevin Schalinske, Kenneth P. Blemings, Daniel W. Steffen, Opal S. Chen, Richard S. Eisenstein

Kevin Schalinske

Iron regulatory proteins (IRPs) are cytoplasmic RNA binding proteins that are central components of a sensory and regulatory network that modulates vertebrate iron homeostasis. IRPs regulate iron metabolism by binding to iron responsive element(s) (IREs) in the 5* or 3* untranslated region of ferritin or transferrin receptor (TfR) mRNAs. Two IRPs, IRP1 and IRP2, have been identified previously. IRP1 exhibits two mutually exclusive functions as an RNA binding protein or as the cytosolic isoform of aconitase. We demonstrate that the BayF3 family of murine pro-B lymphocytes represents the first example of a mammalian cell line that fails to express ...


Effects Of Pasteurella Multocida Toxin On Porcine Bone Marrow Cell Differentiation Into Osteoclasts And Osteoblasts, S. M. Gwaltney, R. J. S. Galvin, K. B. Register, R. B. Rimler, Mark R. Ackermann Sep 1997

Effects Of Pasteurella Multocida Toxin On Porcine Bone Marrow Cell Differentiation Into Osteoclasts And Osteoblasts, S. M. Gwaltney, R. J. S. Galvin, K. B. Register, R. B. Rimler, Mark R. Ackermann

Mark R. Ackermann

The effect of Pasteurella multocida toxin (PMT) on porcine osteoclast and osteoblast differentiation was studied using in vitro cell culture systems. When grown in the presence of Vitamin D3, isolated porcine bone marrow cells formed multinucleated cells with features characteristic of osteoclasts. Exposure of bone marrow cells to Vitamin D3 and PMT during growth resulted in formation of increased numbers and earlier appearance of osteoclasts compared to controls. Ultrafiltered medium from PMT-treated cells likewise increased osteoclast numbers, suggesting that a soluble mediator may be involved in the action of PMT. When cell cultures were treated with fluorescein-labeled PMT, fluorescence was ...


Segregation Of Bismuth To Triple Junctions In Copper, K.-M. Yin, Alexander H. King, T.E. Hsieh, F.-R. Chen, J.J. Kai, L. Chang Sep 1997

Segregation Of Bismuth To Triple Junctions In Copper, K.-M. Yin, Alexander H. King, T.E. Hsieh, F.-R. Chen, J.J. Kai, L. Chang

Alexander H. King

Bismuth segregation in copper has been studied using energy-dispersive X-ray spectrometry (EDX) in a JEOL 2010F transmission electron microscope. In addition to the expected solute enrichment at grain boundaries, we have observed extremely high concentrations of bismuth at certain triple junctions, with significantly greater enrichment factors than in the adjacent grain boundaries. It is shown here that the triple junction segregation is a function of the parameters of the grain boundaries at the triple line, and existence of this type of segregation implies that the affected triple junctions embody excess free energy. At least one of the observed triple junctions ...


Vibrational Spectra In Ordered And Disordered Ni3al, Jeffrey D. Althoff, Dane Morgan, Didier De Fontaine, Mark Asta, S. M. Foiles, Duane D. Johnson Sep 1997

Vibrational Spectra In Ordered And Disordered Ni3al, Jeffrey D. Althoff, Dane Morgan, Didier De Fontaine, Mark Asta, S. M. Foiles, Duane D. Johnson

Duane D. Johnson

We calculate the vibrational density of states (DOS) and corresponding thermodynamic properties of L12 ordered and disordered Ni3Al in the quasiharmonic approximation using the embedded-atom method. Vibrational and thermodynamic properties, including vibrational entropy differences between ordered and disordered states, are found to be in good agreement with experiment. The DOS of the configurationally disordered alloy resembles a broadened version of the DOS of the L12 phase, not a one-atom per cell fcc DOS, and is shifted downward in frequency because the disordered state has a larger volume than the ordered phase. Calculations of the projected DOS indicate that high-frequency modes ...


The Lagrangian Spectral Relaxation Model Of The Scalar Dissipation In Homogeneous Turbulence, Rodney O. Fox Aug 1997

The Lagrangian Spectral Relaxation Model Of The Scalar Dissipation In Homogeneous Turbulence, Rodney O. Fox

Rodney O. Fox

Lagrangian pdf methods are employed to extend the spectral relaxation (SR) model of the scalar dissipation of an inert, passive scalar (1⩽Sc) in homogeneous turbulence. The Lagrangian spectral relaxation (LSR) model divides wavenumber space into a finite number (the total number depending on the Taylor-scale Reynolds numberRλ and the Schmidt number Sc) of wavenumber bands whose time constants are determined from the mean turbulent kinetic energy and instantaneous turbulent energy dissipation rate. The LSR model accounts for the evolution of the scalar spectrum (viz., pdf) from an arbitrary initial shape to its fully developed form. The effect of turbulent-frequencyfluctuations ...


Use Of Ultimate Load Theories For Design Of Drilled Shaft Sound Wall Foundations, Matthew J. Helmers Jun 1997

Use Of Ultimate Load Theories For Design Of Drilled Shaft Sound Wall Foundations, Matthew J. Helmers

Matthew J. Helmers

A study was performed to investigate the factors that affect the accuracy of the procedures used by the Virginia Department of Transportation for design of drilled shaft sound wall foundations. Field load tests were performed on eight inch and nine inch diameter drilled shafts, and the results were compared to theoretical solutions for ultimate lateral load capacity. Standard Penetration Tests were run in the field and laboratory strength tests were performed on the soils from the test sites. It was found that published correlations between blow count and friction angle for sands and gravels can be used to estimate friction ...


Relevant Design Experiences For Agricultural And Biosystems Engineers: Team Focus Through Competition, D. Raj Raman, Ronald E. Yoder Jun 1997

Relevant Design Experiences For Agricultural And Biosystems Engineers: Team Focus Through Competition, D. Raj Raman, Ronald E. Yoder

D. Raj Raman

The multitude of specializations within biosystems engineering makes traditional capstone design courses, which typically focus on a single topic, less relevant. In our department, our year-long capstone design experience involves machine component design. While this experience is useful to students in all concentrations, ideally, students concentrating on biological-, food-, and soil and water-engineering will have a capstone design experience that integrates their unique technical capabilities. New capstone courses should also enhance the broader skills of undergraduate engineers, including teamwork, time and resource management, oral and written communication, and integrated computer skills. However, a variety of issues militate against simply adding ...


The Evolution Of An Introductory Biological Engineering Course: Design Is The Endpoint!, D. Raj Raman Jun 1997

The Evolution Of An Introductory Biological Engineering Course: Design Is The Endpoint!, D. Raj Raman

D. Raj Raman

Four the past four years, I have taught the sophomore level course, Agricultural Engineering 243 Material and Energy Flows in Biological Systems each spring semester. During the first offering, I used the lecture method to transmit information, and homework assignments and exams to reinforce skills and test comprehension. The greatest weakness of this technique seemed the lack of hands-on experience which I gave my students, and their subsequent lack of physical intuition. Enhancing their physical intuition drove the first curricular revision—using in-class demonstrations and simulations of key physical and biological processes. This technique did not work as well as ...


Best-Value Contracting Criteria, Douglas D. Gransberg, Michael A. Ellicott Jun 1997

Best-Value Contracting Criteria, Douglas D. Gransberg, Michael A. Ellicott

Douglas D. Gransberg

Best-value procurements focus on selecting the contractor with the offer most advantageous to the government, when price and other factors are considered. Best-value procurements allow government contracting services to evaluate offers on the basis of total procurement costs, construction quality issues, completion dates, additional features and technical innovations. More importantly, they force the early development of detailed project and procurement plans and create solicitations that contain accurate source-selection criteria. This combination of early planning and quality-based contracting yields significant benefits in construction timeliness, cost containment and customer satisfaction.


Attitude About Engineering Survey, Fall 1995 And 1996: A Study Of Confidence By Gender, Hugh Fuller, Susan C. Grant, Kristine C. Lawyer, Richard L. Porter, Sarah A. Rajala Jun 1997

Attitude About Engineering Survey, Fall 1995 And 1996: A Study Of Confidence By Gender, Hugh Fuller, Susan C. Grant, Kristine C. Lawyer, Richard L. Porter, Sarah A. Rajala

Sarah A. Rajala

One of the primary goals of the North Carolina State University College of Engineering (COE) is to enroll the best undergraduate students possible. One factor hampering the achievement of this goal is the lack of interest of many female high school students in the traditionally male-dominated field of engineering. With no special recruiting activities aimed at informing young women about the field of engineering and recruiting them to our campus, the results are not surprising: even though women represent forty percent of the undergraduate enrollment at the University, they represent just under twenty percent in the COE. In order to ...


Predicting Modes Of Toxic Action From Chemical Structure: Acute Toxicity In The Fathead Minnow (Pimephales Promelas), Steven P. Bradbury, Christine L. Russom, Steven J. Broderius, Dean E. Hammermeister, Robert A. Drummond May 1997

Predicting Modes Of Toxic Action From Chemical Structure: Acute Toxicity In The Fathead Minnow (Pimephales Promelas), Steven P. Bradbury, Christine L. Russom, Steven J. Broderius, Dean E. Hammermeister, Robert A. Drummond

Steven P. Bradbury

In the field of aquatic toxicology, quantitative structure-activity relationships (QSARs) have developed as scientifically credible models for predicting the toxicity of chemicals when little or no empirical data are available. In recent years, there has been an evolution of QSAR development and application from that of a chemical-class perspective to one that is more consistent with assumptions regarding modes of toxic action. The objective of this research was to develop procedures that relate modes of acute toxic action in the fathead minnow (Pimephales promelas) to chemical structures and properties. An empirically derived database for diverse chemical structures of acute toxicity ...


Experimental And Theoretical Investigations Of Order-Disorder In Cu2almn, Duane D. Johnson, M. Asta, J. J. Hoyt, B. C. Chakoumakos, S. T. Misture, J. D. Althoff, R. Mccormack May 1997

Experimental And Theoretical Investigations Of Order-Disorder In Cu2almn, Duane D. Johnson, M. Asta, J. J. Hoyt, B. C. Chakoumakos, S. T. Misture, J. D. Althoff, R. Mccormack

Duane D. Johnson

A combination of X-ray and neutron powder diffraction has been used to measure the two long range order parameters vs. temperature below the disorder-B2 transition in the ternary alloy Cu2 AlMn. The results indicate that at temperatures just below the critical point the Al + Mn sublattice is enriched in Al. First-principles calculations based on only the atomic numbers of Cu, Mn and Al support the experimentally-observed preference of Al for the Al + Mn sublattice, and reveal the interplay between the constituent binary systems that gives rise to this behavior.


Acute Toxicity And Behavioral Effects Of Chlorpyrifos, Permethrin, Phenol, Strychnine, And 2,4-Dinitrophenol To 30-Day-Old Japanese Medaka (Oryzias Latipes), Steven P. Bradbury, Patricia J. Rice, Charles D. Drewes, Theresa M. Klubertanz, Joel R. Coats Apr 1997

Acute Toxicity And Behavioral Effects Of Chlorpyrifos, Permethrin, Phenol, Strychnine, And 2,4-Dinitrophenol To 30-Day-Old Japanese Medaka (Oryzias Latipes), Steven P. Bradbury, Patricia J. Rice, Charles D. Drewes, Theresa M. Klubertanz, Joel R. Coats

Steven P. Bradbury

Five chemicals with different modes of action were evaluated in laboratory studies to determine their acute toxicity (48-h median lethal concentration [LC50]) and behavioral effects on 30-d-old Japanese medaka (Oryzias latipes). The order of toxicity for these xenobiotics was permethrin > chlorpyrifos > 2,4-dinitrophenol (2,4-DNP) > strychnine > phenol. The 48-h LC50s were significantly different and ranged from 0.011 to 24.1 mg/L. In addition, chlorpyrifos and permethrin accumulated in the tissues of juvenile O. latipes. Observations of five behavioral/morphological responses, including changes in equilibrium, general activity, startle response, and morphology (e.g., hemorrhage and deformities) were used as ...


Internet Childhood Safety And Health Resource Guide, Steven A. Freeman, Scott D. Whitman, Roger L. Tormoehlen, Karla M. Embleton Apr 1997

Internet Childhood Safety And Health Resource Guide, Steven A. Freeman, Scott D. Whitman, Roger L. Tormoehlen, Karla M. Embleton

Steven A. Freeman

Purdue University's Agricultural Safety and Health Program, historically a paper-based directory of childhood safety and health resources, is now available on the World Wide Web (WWW). Advantages to WWW publication include: widespread availability, continuous updates, and low distribution costs. Disadvantages include: lack of acceptance by some Extension clientele, loss of portability, and initial difficulties in finding the publication's WWW location. The use of on-line resources has been moderate to date. However, a significant increase in utilization is expected as Internet access becomes less expensive and Extension educators and external clientele become more accustomed to using on-line resources.


Decreased Intracellular Survival Of An Fkpa Mutant Of Salmonella Typhimurium Copenhagen, Shelley M. Horne, Theodore J. Kottom, Lisa K. Nolan, Kevin D. Young Feb 1997

Decreased Intracellular Survival Of An Fkpa Mutant Of Salmonella Typhimurium Copenhagen, Shelley M. Horne, Theodore J. Kottom, Lisa K. Nolan, Kevin D. Young

Lisa K. Nolan

The fkpA gene of Salmonella typhimurium encodes a protein similar to the macrophage infectivity potentiator (Mip) proteins of Legionella pneumophila and Chlamydia trachomatis. Because Mip proteins enhance the ability of these intracellular pathogens to survive within macrophages and epithelial cells, we tested whether the product of the fkpA gene would have the same effect on the intracellular growth of a virulent strain of S. typhimurium. By a series of P22 transductions, the fkpA gene of S. typhimurium Copenhagen was replaced with the inactive fkpA1::omega-Cm gene from Escherichia coli, creating the mutant S. typhimurium KY32H1. The Copenhagen and KY32H1 strains ...


Identification Of A Fish Host Of The Inflated Heelsplitter Potamilus Inflatus( Bivalvia: Unionidae) With A Description Of Its Glochidium, Kevin J. Roe, Andrew M. Simons, Paul Hartfield Jan 1997

Identification Of A Fish Host Of The Inflated Heelsplitter Potamilus Inflatus( Bivalvia: Unionidae) With A Description Of Its Glochidium, Kevin J. Roe, Andrew M. Simons, Paul Hartfield

Kevin J. Roe

A survey of the fishes of the lack Warrior River was undertaken to determine fish host(s) of the federally threatened inflated heelsplitter, Potamilus inflatus. Seven hundred-twenty individual fishes representing 30 species were examined; mussel glochidia were found on 10 individual fishes representing nine species. Potamilus inflatus glochidia were only found infesting one freshwater drum (Aplodinotus grunniens), which is concordant with previous findings for the genus Potamilus. The morphology of P. inflatus glochidia is described and compared to P. purpuratus.


Processing Small Quantities Of Walnut Logs For Lumber And Craft Items, Douglas D. Stokke, Peter Y. S. Chen, J. W. Van Sambeek Jan 1997

Processing Small Quantities Of Walnut Logs For Lumber And Craft Items, Douglas D. Stokke, Peter Y. S. Chen, J. W. Van Sambeek

Douglas D. Stokke

Many walnut plantation owners and woodworking hobbyists would like to process small quantities of walnut logs into lumber and discs for furniture and craft items. Various options exist for sawing, drying, and processing small diameter or short logs into lumber and cross-sectional discs. Portable band saws are a safe and inexpensive log breakdown option to commercial headsaw mills. Processing using the saw-dry-rip method will yield higher quantities of usable lumber from small diameter logs than the conventional saw-rip-dry method. Small quantities of lumber and discs can be inexpensively air dried under shelters or open sheds followed by approximately 15 to ...


The Silviculture-Wood Quality Connection In Eastern Black Walnut, Douglas D. Stokke, Bruce E. Cutter, John E. Phelps Jan 1997

The Silviculture-Wood Quality Connection In Eastern Black Walnut, Douglas D. Stokke, Bruce E. Cutter, John E. Phelps

Douglas D. Stokke

The known effects of silvicultural practices on eastern black walnut (Juglans nigra L.) wood quality are reviewed. Since desirable quality differs from end user to end user, no specific recommendations are made.


Risk Analysis Of Black Walnut And Red Oak Plantations, Douglas D. Stokke, Stephen H. Kolison Jr., Jianbang Gan Jan 1997

Risk Analysis Of Black Walnut And Red Oak Plantations, Douglas D. Stokke, Stephen H. Kolison Jr., Jianbang Gan

Douglas D. Stokke

Risks and uncertainties are prevalent in timber production due to the nature and length of the production process. This paper examines the volatility of timber prices and the effects of some economic uncertainties and risks such as fluctuations in timber prices and the interest rate on the economic returns of black walnut and red oak plantations. Historical patterns of timber prices for black walnut and oaks are investigated and compared with those of other timber species and stock price. The sensitivity of economic returns from black walnut and red oak plantations to changes in timber prices and the discount rate ...


A Computationally-Based Hazard Identification Algorithm That Incorporates Ligand Flexibility. 1. Identification Of Potential Androgen Receptor Ligands, Steven P. Bradbury, Ovanes Mekenyan, Julian Ivanov, Stoyan Karabunarliev, Gerald T. Ankley, Walter Karcher Jan 1997

A Computationally-Based Hazard Identification Algorithm That Incorporates Ligand Flexibility. 1. Identification Of Potential Androgen Receptor Ligands, Steven P. Bradbury, Ovanes Mekenyan, Julian Ivanov, Stoyan Karabunarliev, Gerald T. Ankley, Walter Karcher

Steven P. Bradbury

To advance techniques for screening large data sets of diverse structures for toxicologically active compounds, an algorithm was developed that is not dependent upon a predetermined and specified toxicophore or an alignment of conformers to a lead compound. Instead, the approach provides the means to identify and quantify specific global and local stereoelectronic characteristics associated with active compounds through a comparison of energeticallyreasonable conformer distributions for specific descriptors. To illustrate the algorithm, the stereoelectronic requirements associated with the binding affinity of 28 steroidal and non-steroidal ligands to the androgen receptor were defined. Common ranges of interatomic distances, atomic charges, and ...


Influence Of Geographic Origin And Soil Properties On Color Of Black Walnut Veneer, Douglas D. Stokke, Edward C. Workman Jr., John E. Phelps, Felix Ponder Jr. Jan 1997

Influence Of Geographic Origin And Soil Properties On Color Of Black Walnut Veneer, Douglas D. Stokke, Edward C. Workman Jr., John E. Phelps, Felix Ponder Jr.

Douglas D. Stokke

Walnut veneer frorn sites in Missouri, Illinois, and Indiana was analyzed for color attributes and chemical properties. Veneer color also was compared to an industry color standard. Soil chemical and physical properties were measured on selected sites in each state. In general, walnut trees grown on soils with equal proportions of sand, silt, and clay have better veneer color attributes than trees grown on soils with high clay I sand or clay I silt ratios.


Effects Of Elevated Co2 And Defoliation On Grasses: A Comparative Ecosystem Approach, Brian J. Wilsey, James S. Coleman, Samuel J. Mcnaughton Jan 1997

Effects Of Elevated Co2 And Defoliation On Grasses: A Comparative Ecosystem Approach, Brian J. Wilsey, James S. Coleman, Samuel J. Mcnaughton

Brian J. Wilsey

Three plant species from each of three grassland ecosystems were grown under elevated (700 mL/m3) and ambient (350 mL/m3) CO2 and were defoliated or left undefoliated to test whether species response to elevated CO2 and grazing is related to evolutionary grazing history or to mode of photosynthesis. The three ecosystems represented a tropical grassland dominated by C4 species (the Serengeti of Africa), a temperate grassland dominated by a mixture of C3 and C4 species (Flooding Pampa of South America), and a northern temperate grassland dominated by C3 species (Yellowstone National Park of North America). Plants were grown in ...


Sensors For Site-Specific Management, Stuart J. Birrell, J. W. Hummel, K. A. Sudduth Jan 1997

Sensors For Site-Specific Management, Stuart J. Birrell, J. W. Hummel, K. A. Sudduth

Stuart J. Birrell

Site-specific management (SSM, also known as precision farming, precision agriculture, prescription farming, etc.) is a management strategy that seeks to address within-field variability and to optimize inputs such as pesticides and fertilizers on a point-by-point basis within a field. By reducing over-application and under-application of nutrients and pesticides, this strategy has the potential to improve profitability for the producer and also to reduce the threat of groundwater or surface water contamination from agrichemicals. SSM is being adopted by innovative producers across the country. Agricultural equipment manufacturers, farm input suppliers, and a host of other businesses are working along with publicsector ...


An Insect-Based Detector Of Bovine Manure Odors, D. Raj Raman, Reid R. Gerhardt Jan 1997

An Insect-Based Detector Of Bovine Manure Odors, D. Raj Raman, Reid R. Gerhardt

D. Raj Raman

We designed, constructed, and tested a single-stream insect odormeter for the measurement of bovine manure odors. The biosensing element in the odormeter is a group of six gravid face flies (Musca autumnalis DeGeer) in a 360 mL chamber. A microphone, mounted above the chamber, senses sounds made by the flies’ activity. The microphone signal is processed by an analog root-mean-square power-measuring circuit connected to a computer data acquisition system. The apparatus allows electronic measurement of insect activity. Initial experiments demonstrate the feasibility of this system for odor detection (yes/no). Kinetic experiments show that a dose-response curve can be produced ...


The S0 State Of The Oxygen-Evolving Complex In Photosystem Ii Is Paramagnetic:  Detection Of An Epr Multiline Signal, Johannes Messinger, John H. Robblee, Edward Yu, Kenneth Sauer, Vittal K. Yachandra, Melvin P. Klein Jan 1997

The S0 State Of The Oxygen-Evolving Complex In Photosystem Ii Is Paramagnetic:  Detection Of An Epr Multiline Signal, Johannes Messinger, John H. Robblee, Edward Yu, Kenneth Sauer, Vittal K. Yachandra, Melvin P. Klein

Edward Yu

The photosynthetic oxidation of water to molecular oxygen is energetically driven by light-induced charge separations in the reaction center of photosystem II (PS II). The reaction is catalyzed by a tetranuclear manganese cluster contained in the oxygen-evolving complex (OEC). The OEC cycles through five different redox states termed S0 to S4, with S1 being the darkstable state. Oxygen is released during the S4 f S0 transition.1 The removal of one electron from the OEC on each S state transition leads to the idea that alternate S states should be paramagnetic because of their odd-electron number. The multiline EPR signal ...