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Articles 2101 - 2130 of 2597

Full-Text Articles in Agricultural Science

Tillage And Beef Cattle Manure Effects On Soil Nitrogen In A Dryland Rotation, R. C. Schwartz, R.L. Baumhardt, T.H. Dao Jan 2002

Tillage And Beef Cattle Manure Effects On Soil Nitrogen In A Dryland Rotation, R. C. Schwartz, R.L. Baumhardt, T.H. Dao

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Minimum tillage practices used in dryland cropping systems that reduce soil water evaporation and erosion may also decrease efficiency of manure nutrient utilization. We initiated a study in 1997 to investigate the effects of surface-applied stockpiled and composted beef cattle (Bos taurus) manure on soil N and sorghum [Sorghum bicolor (L.) Moench] and wheat (Triticum aestivum L.) yields and N-uptake within a wheat-sorghum-fallow dryland crop rotation. Paired terraces with no-tillage (NT) and stubble-mulch tillage (ST) systems were main plots of a single rotation phase. Stockpiled manure, composted manure, or commercial fertilizer (urea + ammonium phosphate) were …

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Particulate Soil Organic Matter Carbon In Surface Soils After 12 Years In No-Till Dryland Cropping Systems, L.A. Sherrod, G. A. Peterson, D.G. Westfall, L.R. Ahuja Jan 2002

Particulate Soil Organic Matter Carbon In Surface Soils After 12 Years In No-Till Dryland Cropping Systems, L.A. Sherrod, G. A. Peterson, D.G. Westfall, L.R. Ahuja

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Soil organic carbon (SOC) in the surface soils has increased when summer fallow is reduced or eliminated in the central Great Plains. We evaluated the effect of no-till cropping systems of WF, wheat-com-fallow (WCF), wheat-corn-millet-fallow (WCMF), opportunity cropping (OPP), and native grass species (G) on particulate organic matter (POM-C) and mineral associated C in the silt and clay fractions. Soil organic carbon (SOC) has increased with increasing cropping intensity after 12 years, of no-till management. Particulate organic matter C accounted for 38 to 52 % of the total SOC in the 0-2.5 cm and 24 to 48 % of the …

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Development Of Granular Boric Acid Sugar Baits For House Flies (Diptera: Muscidae), Jerome A. Hogsette, David A. Carlson, Alyce S. Nejame Jan 2002

Development Of Granular Boric Acid Sugar Baits For House Flies (Diptera: Muscidae), Jerome A. Hogsette, David A. Carlson, Alyce S. Nejame

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Freeze-dried, granular sugar baits containing boric acid as the toxicant were evaluated against house flies, Musca domestica L., in two bioassays with toxicant dose ranges of 3, 5, 7, 8, and 12%, and 3, 5, 9, 17, and 33% boric acid, respectively, calculated and expressed on a dry weight basis. Flies in bioassay 1 were mixed sex and unstarved and flies in bioassay 2 were females only and starved 4 h before testing began. LC50s were 8.97 and 14.33%, and LT50s were 59.75 and 53.34 h in bioassays 1 and 2, respectively. Baits were tested at …

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Development Of Hydrotaea Aenescens (Diptera: Muscidae) In Manure Of Unweaned Dairy Calves And Lactating Cows, Jerome Hogsette, Robert Farkas, Reginald Coler Jan 2002

Development Of Hydrotaea Aenescens (Diptera: Muscidae) In Manure Of Unweaned Dairy Calves And Lactating Cows, Jerome Hogsette, Robert Farkas, Reginald Coler

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

In laboratory studies performed in the United States and Hungary, the dump fly Hydrotaea aenescens (Wiedemann) was reared successfully in manure of 1- to 8-wk-old dairy calves, and in manure from adult lactating dairy cows. Survival in manure collected from 1-wk-old calves was poor (7.2%), better in manure collected from 2- and 3-wk-old calves (53.5%), and best in manure collected from 4- to 8-wk-old calves (71.4%). Survival in cow manure was slightly lower (47.4%) than that in calf manure. Reasons for different rates of development in the United States and in Hungary, and by calf age are discussed as are …

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Thermal Death Kinetics And Heatingrate Effects For Fifth-Instar Cydia Pomonella (L.) (Lepidoptera: Tortricidae), S. Wang, J. N. Ikediala, J. Tang, J. D. Hansen Jan 2002

Thermal Death Kinetics And Heatingrate Effects For Fifth-Instar Cydia Pomonella (L.) (Lepidoptera: Tortricidae), S. Wang, J. N. Ikediala, J. Tang, J. D. Hansen

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Thermal death kinetic parameters of fifth-instar codlingmoths (Cydia pomonella (L.)) and the effect of three heating rates (1°Cmin-1, 10°Cmin-1, and 18°Cmin-1) on larval mortality were determined by a heatingblock system. The insects were heated to four temperatures (46°C, 48°C, 50°C, and 52°C) held for predetermined periods followed by 24 h storage at 4°C before mortality evaluation. Thermal death kinetics for fifth-instar codlingmoths followed a 0.5th order of kinetic reaction. Minimum time required to achieve 100% mortality of a given population decreased with temperature in a semi-logarithmic manner. No larval survival was observed in …

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Crop Sequence, Tillage, And Nitrogen Fertilization Effects On Soil Ph In The Northern Great Plains, Mark A. Liebig, D. L. Tanaka, A.L. Black Jan 2002

Crop Sequence, Tillage, And Nitrogen Fertilization Effects On Soil Ph In The Northern Great Plains, Mark A. Liebig, D. L. Tanaka, A.L. Black

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Decreases in soil pH in agricultural soils can affect plant nutrient availability and crop yield. For soils possessing high levels of calcareous minerals, such as those found throughout much of the Northern Great Plains, decreases in soil pH can also enhance C loss to the atmosphere due to acid decomposition of CaCO3. We evaluated changes in soil pH over a 16 yr period for a long-term cropping systems experiment established on calcareous parent material near Mandan, ND. Management variables included in the experiment were crop sequence [spring wheat-fallow (SW-F) and spring wheat-winter wheat-sunflower (SW-WW-SF)], tillage (conventional, minimum, no-till), …

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Identification Of Waxy Wheat By Near-Infrared Reflectance Spectroscopy, S. R. Delwiche, Robert A. Graybosch Jan 2002

Identification Of Waxy Wheat By Near-Infrared Reflectance Spectroscopy, S. R. Delwiche, Robert A. Graybosch

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Newly developed low amylose wheats (Triticum aestivum L.) have unique processing characteristics and thus allow millers to blend defined levels of amylose in mixes requiring low-amylose flour. The amount of amylose synthesized during grain fill is dependent on the expression of three structural genes that encode isoforms of granule-bound starch synthase (GBSS). Lines possessing null alleles at the three waxy (wx) loci produce starch that lacks amylose. While such wheats are readily identified by iodine staining, their identification in wheat marketing and production systems would be facilitated by the use of rapid, spectral methods. The present study …

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Review And Interpretation: Nitrogen Management Strategies To Reduce Nitrate Leaching In Tile-Drained Midwestern Soils, Dana L. Dinnes, Douglas L. Karlen, Dan B. Jaynes, Thomas C. Kaspar, Jerry L. Hatfield, Thomas S. Colvin, Cynthia A. Cambardella Jan 2002

Review And Interpretation: Nitrogen Management Strategies To Reduce Nitrate Leaching In Tile-Drained Midwestern Soils, Dana L. Dinnes, Douglas L. Karlen, Dan B. Jaynes, Thomas C. Kaspar, Jerry L. Hatfield, Thomas S. Colvin, Cynthia A. Cambardella

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Balancing the amount of N needed for optimum plant growth while minimizing the NO3 that is transported to ground and surface waters remains a major challenge for everyone attempting to understand and improve agricultural nutrient use efficiency. Our objectives for this review are to examine how changes in agricultural management practices during the past century have affected N in Midwestern soils and to identify the types of research and management practices needed to reduce the potential for nonpoint NO3 leakage into water resources. Inherent soil characteristics and management practices contributing to nonpoint NO3 loss from Midwestern soils, …

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Molecular Cloning, Functional Characterization, And Subcellular Localization Of Soybean Nodule Dihydrolipoamide Reductase, Jose F. Moran, Zhaohui Sun, Gautam Sarath, Raul Arredondo-Peter, Euan K. James, Manuel Becana, Robert V. Klucas Jan 2002

Molecular Cloning, Functional Characterization, And Subcellular Localization Of Soybean Nodule Dihydrolipoamide Reductase, Jose F. Moran, Zhaohui Sun, Gautam Sarath, Raul Arredondo-Peter, Euan K. James, Manuel Becana, Robert V. Klucas

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Nodule ferric leghemoglobin reductase (FLbR) and leaf dihydrolipoamide reductase (DLDH) belong to the same family of pyridine nucleotide-disulfide oxidoreductases. We report here the cloning, expression, and characterization of a second protein with FLbR activity, FLbR-2, from soybean (Glycine max) nodules. The cDNA is 1,779 bp in length and codes for a precursor protein comprising a 30-residue mitochondrial transit peptide and a 470-residue mature protein of 50 kD. The derived protein has considerable homology with soybean nodule FLbR-1 (93% identity) and pea (Pisum sativum) leaf mitochondria DLDH (89% identity). The cDNA encoding the mature protein was overexpressed …

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Continuous Production Of Extracellular Antioxidants In Suspension Cells Attenuates The Oxidative Burst Detected In Plant Microbe Interactions, C. Jacyn Baker, Nichole R. O'Neil, Kenneth Deahl, John Lydon Jan 2002

Continuous Production Of Extracellular Antioxidants In Suspension Cells Attenuates The Oxidative Burst Detected In Plant Microbe Interactions, C. Jacyn Baker, Nichole R. O'Neil, Kenneth Deahl, John Lydon

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Suspension cells of Solanacearum tuberosum and Nicotiana tabacum placed in fresh buffer rapidly produce and maintain significant pools of extracellular antioxidants. The extracellular antioxidant was detected by first adding a known amount of exogenous H2O2 to samples and then immediately measuring the remaining H2O2. The difference between the amount added and amount remaining was used to determine the antioxidant capacity of the sample. This extracellular antioxidant pool attenuates levels of hydrogen peroxide produced during plant–bacterial interactions. When tobacco cells were inoculated with an isolate Pseudomonas syringae pv. syringae that causes a hypersensitive response …

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Oestrus Ovis In Sheep: Relative Third-Instar Populations, Risks Of Infection And Parasitic Control, Guillaume Tabouret, Philippe Jacquiet, Philip Scholl, Philippe Dorchies Nov 2001

Oestrus Ovis In Sheep: Relative Third-Instar Populations, Risks Of Infection And Parasitic Control, Guillaume Tabouret, Philippe Jacquiet, Philip Scholl, Philippe Dorchies

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Oestrus ovis (L.) (Diptera: Oestridae), the nasal bot fly, has a relatively short free-living life cycle outside of the host, and therefore it is necessary to know when the parasitic period occurs in order to prevent the clinical signs and economic losses caused by this parasite. The length of this parasitic portion of the life cycle is quite variable: a few weeks to several months depending on the season and climatic conditions. Surveys of Oestrus ovis larval populations in sheep show different results on the number of generations according to the local climate. Mean monthly larval profiles of L1 and …

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Structure And Temporal Dynamics Of Populations Within Wheat Streak Mosaic Virus Isolates, Jeffrey S. Hall, Roy C. French, Thomas Jack Morris, Drake C. Stenger Nov 2001

Structure And Temporal Dynamics Of Populations Within Wheat Streak Mosaic Virus Isolates, Jeffrey S. Hall, Roy C. French, Thomas Jack Morris, Drake C. Stenger

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Variation within the Type and Sidney 81 strains of wheat streak mosaic virus was assessed by single-strand conformation polymorphism (SSCP) analysis and confirmed by nucleotide sequencing. Limiting-dilution subisolates (LDSIs) of each strain were evaluated for polymorphism in the P1, P3, NIa, and CP cistrons. Different SSCP patterns among LDSIs of a strain were associated with single-nucleotide substitutions. Sidney 81 LDSI-S10 was used as founding inoculum to establish three lineages each in wheat, corn, and barley. The P1, HC-Pro, P3, CI, NIa, NIb, and CP cistrons of LDSI-S10 and each lineage at passages 1, 3, 6, and 9 were evaluated for …

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Frequency Grid-A Simple Tool For Measuring Grassland Establishment, Kenneth P. Vogel, Robert A. Masters Nov 2001

Frequency Grid-A Simple Tool For Measuring Grassland Establishment, Kenneth P. Vogel, Robert A. Masters

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Simple, reliable tools are needed by land managers to quantify establishment success when seeding or re-seeding pastures or rangeland. A frequency grid was designed to measure seedling or plant establishment success for a single species, mixtures of species, or single species of a mixture. The frequency grid is a metal frame containing 25 squares (5 x 5) or cells and can be made from concrete reinforcing sheets that have 15 x 15 cm squares. When used, the frequency grid is either randomly or systematically placed within a seeded area. The number of cells containing 1 or more seeded plants is …

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Accumulation And Consumption Of Odorous Compounds In Feedlot Soils Under Aerobic, Fermentative, And Anaerobic Respiratory Conditions, D. N. Miller Oct 2001

Accumulation And Consumption Of Odorous Compounds In Feedlot Soils Under Aerobic, Fermentative, And Anaerobic Respiratory Conditions, D. N. Miller

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Agricultural odors present an increasingly difficult challenge to livestock producers, yet very little information is available on the microbiology of odor production or microbial factors that regulate the emission of odors. This study examined the microbial potential for odor production and odor consumption in two soils from a cattle production facility in central Nebraska. The two soils tested were collected from a feedlot pen and a runoff ditch below the pen and contained high- and low-fecal matter content, respectively. These soils were tested for their ability to produce and consume a mixture of VFA and aromatic compounds (phenols and indoles) …

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‘Forrest’ Resistance To The Soybean Cyst Nematode Is Bigenic: Saturation Mapping Of The Rhg1 And Rhg4 Loci, K. Meksem, P. Pantazopoulos, V. N. Njiti, D. L. Hyten, P. R. Arelli, D. A. Lightfoot Oct 2001

‘Forrest’ Resistance To The Soybean Cyst Nematode Is Bigenic: Saturation Mapping Of The Rhg1 And Rhg4 Loci, K. Meksem, P. Pantazopoulos, V. N. Njiti, D. L. Hyten, P. R. Arelli, D. A. Lightfoot

Department of Agronomy and Horticulture: Faculty Publications

Field resistance to cyst nematode (SCN) race 3 (Heterodera glycines I.) in soybean [Glycine max (L.) Merr.] cv ‘Forrest’ is conditioned by two QTLs: the underlying genes are presumed to include Rhg1 on linkage group G and Rhg4 on linkage group A2. A population of recombinant inbred lines (RILs) and two populations of near-isogenic lines (NILs) derived from a cross of Forrest × Essex were used to map the loci affecting resistance to SCN. Bulked segregant analysis, with 512 AFLP primer combinations and microsatellite markers, produced a high-density genetic map for the intervals carrying Rhg …

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Corn Stalk Nitrate Concentration Profile: Implications For The End-Of-Season Stalk Nitrate Test, Wally Wilhelm, Gary E. Varvel, James S. Schepers Oct 2001

Corn Stalk Nitrate Concentration Profile: Implications For The End-Of-Season Stalk Nitrate Test, Wally Wilhelm, Gary E. Varvel, James S. Schepers

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The end-of-season corn (Zea maysL.) stalk nitrate-N test was developed as a post-mortem to determine if excessive or insufficient N was available to the corn crop during the latter part of the season. The stalk section specified for the test was very specific, the 20 cm-long section between 15 and 35 cm above the soil. Under production conditions, it may not always be possible to collect this precise stalk section. The objective of this study was to determine how nitrate concentration varied within the stalk from the soil level to the ear node, and how this variation could …

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Thermoregulatory Profile Of A Newer Genetic Line Of Pigs, T. M. Brown-Brandl, R. A. Eigenberg, John A. Nienaber, Stephen D. Kachman Sep 2001

Thermoregulatory Profile Of A Newer Genetic Line Of Pigs, T. M. Brown-Brandl, R. A. Eigenberg, John A. Nienaber, Stephen D. Kachman

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Researchers and producers alike have noted the increased susceptibility to heat stress exhibited by the newer genetic lines of pigs. A study was conducted to gather baseline information on the effects of acute heat stress on total heat production (THP), respiratory quotient (RQ), respiration rate (RR), and rectal temperature (Trectal ) and to investigate the dynamic interaction of these parameters in growing–finishing barrows. Sixteen moderate–lean growth barrows were randomly assigned to a set of treatments as dictated by a repeated 4x4 Latin square crossover design. Pigs were moved from an individual pen to an indirect calorimeter where one …

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Murine Monoclonal Antibodies Against Escherichia Coli O4 Lipopolysaccharide And H5 Flagellin, Mildred Rivera-Betancourt, James E. Keen Sep 2001

Murine Monoclonal Antibodies Against Escherichia Coli O4 Lipopolysaccharide And H5 Flagellin, Mildred Rivera-Betancourt, James E. Keen

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Two murine monoclonal antibodies (MAb), 2C5-F10 and 8D1-H10, reactive with Escherichia coli O4 and H5 antigens, respectively, were generated and characterized. Enzyme immunoassays and immunoblots demonstrated that MAb 2C5-F10 reacted specifically with lipopolysaccharide O antigen of E. coli O4 isolates, while MAb 8D1-H10 reacted with E. coli strains expressing H5 flagella.

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Invited Synthesis Paper: Principles And Practices For Managing Rangeland Invasive Plants, Robert A. Masters, Roger Sheley Sep 2001

Invited Synthesis Paper: Principles And Practices For Managing Rangeland Invasive Plants, Robert A. Masters, Roger Sheley

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Invasive plants reduce the capacity of ecosystems to provide goods and services required by society, alter ecological processes, and can displace desirable species. They can reduce wildlife habitat quality, riparian area integrity, rangeland economic value, and enterprise net returns. The invasion process is regulated by characteristics of the invading plant and the community being invaded. The presence and spread of invasive plants is often symptomatic of underlying management problems that must be corrected before acceptable, long-term rangeland improvement can be achieved. Disturbance appears to be important early in the invasion process because it creates vacant niches that alien plants can …

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Genotypic Analyses Of Escherichia Coli O157:H7 And O157 Nonmotile Isolates Recovered From Beef Cattle And Carcasses At Processing Plants In The Midwestern States Of The United States, Genevieve A. Barkocy-Gallagher, Terrance M. Arthur, Gregory R. Siragusa, James E. Keen, Robert O. Elder, William Laegreid, Mohammad Koohmaraie Sep 2001

Genotypic Analyses Of Escherichia Coli O157:H7 And O157 Nonmotile Isolates Recovered From Beef Cattle And Carcasses At Processing Plants In The Midwestern States Of The United States, Genevieve A. Barkocy-Gallagher, Terrance M. Arthur, Gregory R. Siragusa, James E. Keen, Robert O. Elder, William Laegreid, Mohammad Koohmaraie

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Escherichia coli O157:H7 and O157 nonmotile isolates (E. coli O157) previously were recovered from feces, hides, and carcasses at four large Midwestern beef processing plants (R. O. Elder, J. E. Keen, G. R. Siragusa, G. A. Barkocy-Gallagher, M. Koohmaraie, and W. W. Laegreid, Proc. Natl. Acad. Sci. USA 97:2999–3003, 2000). The study implied relationships between cattle infection and carcass contamination within single-source lots as well as between preevisceration and postprocessing carcass contamination, based on prevalence. These relationships now have been verified based on identification of isolates by genomic fingerprinting. E. coli O157 isolates from all positive samples were analyzed …

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Chemical Compounds That Attract Arthropods- Patent 2001, Ulrich R. Bernier, Daniel L. Kline, Donald Barnard, Kenneth Posey, Matthew Booth, Richard A. Yost Jul 2001

Chemical Compounds That Attract Arthropods- Patent 2001, Ulrich R. Bernier, Daniel L. Kline, Donald Barnard, Kenneth Posey, Matthew Booth, Richard A. Yost

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Compositions and methods employing the compositions for attracting arthropods. The compositions comprise at least one compound of formula I and at least one compound from group II.

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Performance Of A Grid-Connected Photovoltaic System Using Actual And Kriged Hourly Solar Radiation, G. G. Merino, David Jones, Laverne E. Stetson Jul 2001

Performance Of A Grid-Connected Photovoltaic System Using Actual And Kriged Hourly Solar Radiation, G. G. Merino, David Jones, Laverne E. Stetson

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

In this article the performance of a grid-connected PV system supplying a farmstead was evaluated using a commercially available energy balance simulation model, Hybrid2. By performing annual hourly simulations, the influence of system size, actual radiation data, and estimated radiation data on economic and energy production were assessed. The estimated radiation data were developed from kriging actual radiation data from 16 weather stations in western Nebraska. The results indicated that the capital costs associated with a PV system dictate the economic performance of the overall system. The energy costs associated with the grid-connected PV system were six times the retail …

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Restoring Tallgrass Prairie Species Mixtures On Leafy Spurge-Infested Rangeland, Robert A. Masters, Daniel Beran, Roch E. Gaussoin Jul 2001

Restoring Tallgrass Prairie Species Mixtures On Leafy Spurge-Infested Rangeland, Robert A. Masters, Daniel Beran, Roch E. Gaussoin

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Leafy spurge (Euphorbia esula L.) reduces northern Great Plains rangeland carrying capacity. Treatment strategies were evaluated that suppressed leafy spurge and facilitated establishment of mixtures of native grasses and legumes on range sites near Mason City and Tilden, Nebr. Glyphosate at 1,600 g a.i. (active ingredient) ha-1 was applied with or without imazapic at 140 or 210 g a.i. ha-1 in October 1995. In April 1996, standing crop was burned or mowed. Mixtures of native grasses [big bluestem (Andropogon gerardii Vitman), indiangrass (Sorghastrum nutans (L.) Nash), switchgrass (Panicum virgatum L.), little bluestem (Schizachyrium …

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Modeling Vegetative Buffer Performance Considering Topographic Data Accuracy, Jason M. Brothers, Dean E. Eisenhauer, Matthew J. Helmers, Michael G. Dosskey, Thomas G. Franti Jul 2001

Modeling Vegetative Buffer Performance Considering Topographic Data Accuracy, Jason M. Brothers, Dean E. Eisenhauer, Matthew J. Helmers, Michael G. Dosskey, Thomas G. Franti

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Riparian buffers are a promising tool in efforts to reduce sediment contribution to streams. Models that predict the capacity of buffers to trap sediment have recently been developed. A number of parameters that are required to conduct such modeling efforts are derived from the topography of the site. In this study, three topographic data sources were used to generate the model input for an agricultural field with a riparian buffer. The runoff and sediment transport in the system was then simulated for three years. As a result, the area that contributed runoff and sediment to the buffer was substantially different …

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Mutations In The Csgd Promoter Associated With Variations In Curli Expression In Certain Strains Of Escherichia Coli O157:H7, Gaylen A. Uhlich, James E. Keen, Robert O. Elder May 2001

Mutations In The Csgd Promoter Associated With Variations In Curli Expression In Certain Strains Of Escherichia Coli O157:H7, Gaylen A. Uhlich, James E. Keen, Robert O. Elder

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Single-base-pair csgD promoter mutations in human outbreak Escherichia coli O157:H7 strains ATCC 43894 and ATCC 43895 coincided with differential Congo red dye binding from curli fiber expression. Red phenotype csgD::lacZ promoter fusions had fourfold-greater expression than white promoter fusions. Cloning the red variant csgDEFG operon into white variants induced the red phenotype. Substrate utilization differed between red and white variants.

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Erythropoietin Mrna Expression In Pig Embryos, H. G. Klemcke, J. L. Vallet, R. K. Christenson, P. L. Pearson Apr 2001

Erythropoietin Mrna Expression In Pig Embryos, H. G. Klemcke, J. L. Vallet, R. K. Christenson, P. L. Pearson

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

To address whether altered erythropoietin (EPO) synthesis might be involved in prenatal pig mortality, studies were conducted to measure porcine embryonic EPO mRNA expression during early gestation (days 24–40). Three pig models differing in embryonic survival from days 24–40 were investigated: intact white crossbred gilts (INT), white crossbred gilts that were unilaterally hysterectomized-ovariectomized before puberty and whose pregnant uterus constituted a crowded environment (UHO), and prolific, intact Meishan gilts (ME). A partial cDNA for porcine EPO, developed via reverse transcription and polymerase chain reaction procedures was used to generate a 32P-labeled probe for use in Northern analyses. In an initial …

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Modeling A Spring Wheat Crop Under Elevated Co2 And Drought, S. Grossman-Clarke, P. J. Pinter Jr., T. Kartschall, B. A. Kimball, D. J. Hunsaker, G. W. Wall, R. L. Garcia, R. L. Lamorte Mar 2001

Modeling A Spring Wheat Crop Under Elevated Co2 And Drought, S. Grossman-Clarke, P. J. Pinter Jr., T. Kartschall, B. A. Kimball, D. J. Hunsaker, G. W. Wall, R. L. Garcia, R. L. Lamorte

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

• The simulation model DEMETER was used here to investigate which mechanisms led to a larger CO2 effect on biomass production and yield of a spring wheat crop under drought compared with unlimited water supply.

• Field data of the free-air CO2enrichment (FACE) wheat experiments in Arizona (1993–94) were used to test the model. The influence of a particular mechanism leading to a higher CO2effect under drought was investigated by eliminating the influence of the other causes on the simulation results on selected days during the growing seasons.

• A larger CO2effect under …

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Plant-Derived Oils Reduce Pathogens And Gaseous Emissions From Stored Cattle Waste, Vincent H. Varel, Daniel N. Miller Mar 2001

Plant-Derived Oils Reduce Pathogens And Gaseous Emissions From Stored Cattle Waste, Vincent H. Varel, Daniel N. Miller

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Carvacrol and thymol in combination at 6.7 mM each completely inhibited the production of short-chain volatile fatty acids and lactate from cattle waste in anoxic flasks over 23 days. Fecal coliforms were reduced from 4.6 x 106 to 2.0 x 103 cells per ml 2 days after treatment and were nondetectable within 4 days. Total anaerobic bacteria were reduced from 8.4 x 1010 to 1.5 x 107 cells per ml after 2 days and continued to be suppressed to that level after 14 days. If the concentration of carvacrol or thymol were doubled (13.3 mM), either …

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Evaluation Of Gel Filtration Resins For The Removal Of Pcr-Inhibitory Substances From Soils And Sediments, Daniel N. Miller Jan 2001

Evaluation Of Gel Filtration Resins For The Removal Of Pcr-Inhibitory Substances From Soils And Sediments, Daniel N. Miller

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

A variety of gel filtration resins (Sephadex G200 and G150; Sepharose 6B, 4B and 2B; Bio-Gel P100, P200; and Toyopearl HW 55, HW 65, and HW 75) were evaluated for their efficacy in removing PCR-inhibitory substances from feedlot soil DNA crude extracts using gravity-flow disposable columns. Sepharose resins demonstrated the best properties for DNA purification when compared to other gel filtration resins, and Sepharose 2B was the most efficient purification resin based upon flow rate and the elution of DNA and humic acids from the columns. A method for purifying large solution volumes of DNA extract economically was also developed …

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Intsormil 2001 Annual Report, John M. Yohe, Thomas Crawford Jr., Joan Frederick, Dorothy Stoner Jan 2001

Intsormil 2001 Annual Report, John M. Yohe, Thomas Crawford Jr., Joan Frederick, Dorothy Stoner

INTSORMIL Impacts and Bulletins

Presently, worldwide, more than 800 million people are hungry and over one billion are desperately poor, and food demand is increasing rapidly. The majority of poor live in rural areas in developing countries and agricultural and food systems development is vital to economic growth; improving environmental quality; strengthening nutrition, health and child survival; improving the status of women; and promoting democratization. It is estimated that, between 1980 and 2030, the population ofow- and middle-income countries will more than double-to seven billion, compared with one billion for high-income countries. In the next 35 years, 2.5 billion people will be added to …

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