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Transactions Ofthe Nebraska Academy Of Sciences: Volume 28, 2002 Table Of Contents
Transactions Ofthe Nebraska Academy Of Sciences: Volume 28, 2002 Table Of Contents
Transactions of the Nebraska Academy of Sciences and Affiliated Societies
Table of Contents
Editorial Contents
Nebraska Academy of Sciences, Inc..........................inside front cover
Nebraska Association of Teachers of Science..........................inside front cover
Nebraska Executive Committee, Policy Committee..........................ii
Editorial Board..........................iv
Preparation of manuscripts..........................inside back cover
Papers
Additions to the lichen flora of Nebraska (Robert S. Egan, Sara Morgan, Clifford M. Wetmore, and Douglas Ladd)..........................1
Germination of threadleaf sedge (Cyperaceae: Carex filifolia) (Gina R. Tichota and James Stubbendieck)..........................15
Morphological variation of Alloereadium lobatum (Digenea: Allocreadiidae) in the creek chub, Semotilus atromaeulatus (Osteichthyes: Cyprinidae), in Nebraska, USA (Monte S. Willis)..........................21
Insects and the native vegetation of Nebraska (Brett C. Ratcliffe and Paul C. Hammond)..........................29 …
Food Habits Of Yellow Perch, Perca Flavescens, In West Long Lake, Nebraska, Justin L. Wilkens, Timothy J. Debates, David W. Willis
Food Habits Of Yellow Perch, Perca Flavescens, In West Long Lake, Nebraska, Justin L. Wilkens, Timothy J. Debates, David W. Willis
Transactions of the Nebraska Academy of Sciences and Affiliated Societies
Food-habits data were collected from 102 yellow perch, Perca flavescens, in West Long Lake, Nebraska, from April to October, 2001, to determine iffood habits changed seasonally in this shallow, vegetated, natural lake. Based on percent by number and weight, yellow perch in all length groups and during all seasons primarily consumed macro-invertebrates. Yellow perch < 130 mm in total length fed primarily on amphipods and chironomids in all months except October. For perch between 130 and 199 mm, amphipods and chironomids composed greater than 60% of the diet by weight in all months except August. Yellow perch ≥ 200 mm primarily consumed macro-invertebrates with fish contributing less than 6% ofthe diet by weight during all months except June. Knowledge of the trophic ecology of yellow perch in these lentic systems should help biologists better understand the role of perch as both predator and prey.
Morphological Variation Of Allocreadium Lobatum (Digenea: Allocreadiidae) In The Creek Chub, Semotilus Atromaculatus (Osteichthyes: Cyprinidae), In Nebraska, Usa, Monte S. Willis
Transactions of the Nebraska Academy of Sciences and Affiliated Societies
Allocreadium lobatum Wallin 1909, a parasite of fresh-water fish, was originally described as having distinct lobate testes, and subsequent descriptions have left this original description unchanged. The present study quantifies the observation of distinctly non-lobate testes that could be categorized as round or asymmetrical in addition to the previously described lobate testes. Six hundred thirty-six A. lobatum were collected from 228 Semotilus atromaculatus over a 9 month period. Overall, 21.3%, 61.6%, and 16% were found to be round, asymmetrical, and lobate testes respectively (N = 1,071). Analysis of testis morphology found the increasing presence of lobate testis as …
Geostatistical Analysis Of The Small-Scale Distribution Of European Corn Borer (Lepidoptera: Crambidae) Larvae And Damage In Whorl Stage Corn, Robert J. Wright, Terry A. Devries, Linda J. Young, Keith J. Jarvi, Ronald C. Seymour
Geostatistical Analysis Of The Small-Scale Distribution Of European Corn Borer (Lepidoptera: Crambidae) Larvae And Damage In Whorl Stage Corn, Robert J. Wright, Terry A. Devries, Linda J. Young, Keith J. Jarvi, Ronald C. Seymour
Department of Entomology: Faculty Publications
The small-scale spatial distribution of European corn borer, Ostrinia nubilalis (Hübner), larvae and damage in whorl stage corn, Zea mays L., was characterized using geostatistics. Spatial distribution of O. nubilalis larval feeding damage was studied at Clay Center, North Platte, and Concord, NE, during June-July 1992-1994, and spatial distribution of O. nubilalis larvae and damage was studied at Clay Center in June 1997. Semivariograms were calculated to model the change in spatial correlation with increasing distance between samples. Spatial distribution of larval damage during 1992-1994 was best described using a spherical model. Damage was spatially correlated among plants at distances …
Random Amplified Polymorphic Dna Markers For Discriminating Cochliomyia Hominivorax From C. Macellaria (Diptera: Calliphoridae), S. R. Skoda, Saowaluck Pornkulwat, John E. Foster
Random Amplified Polymorphic Dna Markers For Discriminating Cochliomyia Hominivorax From C. Macellaria (Diptera: Calliphoridae), S. R. Skoda, Saowaluck Pornkulwat, John E. Foster
Department of Entomology: Faculty Publications
The screwworm, Cochliomyia hominivorax (Coquerel), is one of the most important pests of livestock in the Western Hemisphere. During early immature stages it is morphologically very similar (first instars are virtually indistinguishable) to the secondary screwworm, C. macellaria (Fabricius). Here, the utility of the random amplified polymorphic DNA–polymerase chain reaction (RAPD–PCR) was explored as a technique for developing molecular genetic markers for these two species. Of the 120 arbitrary primers screened, 21 primers produced markers that were further investigated. Seven of the 21 primers produced clear and reproducible markers that were tested with DNA of five individuals from four populations …
Reduction Of Moniliformin During Alkaline Cooking Of Corn, Graciela Pineda-Valdes, Dojin Ryu, David S. Jackson, Lloyd B. Bullerman
Reduction Of Moniliformin During Alkaline Cooking Of Corn, Graciela Pineda-Valdes, Dojin Ryu, David S. Jackson, Lloyd B. Bullerman
Department of Food Science and Technology: Faculty Publications
The incidence of moniliformin (MON) producing Fusarium spp. in selected corn (Zea mays L.) samples from Mexico and the United States and the effects of alkaline cooking and the tortilla manufacturing processes on the reduction of MON were determined. The percentage of infected kernels with Fusariumspp. ranged from 0 to 22% in eight food-grade corn samples, including six from Mexico and two from the United States. Complete (100%) reduction of MON was observed when a naturally contaminated com sample containing 1.4 µg of MON/g of corn was used in a pilot-scale alkaline cooking and tortilla manufacturing process. In …
Enzymatic Process For Nixtamalization Of Cereal Grains, David S. Jackson, Deepak Sahai
Enzymatic Process For Nixtamalization Of Cereal Grains, David S. Jackson, Deepak Sahai
Department of Food Science and Technology: Faculty Publications
Disclosed are novel methods of producing food compositions by the use of an enzymatic digestion of the component parts of whole portions of cereal grains, and grain materials, to impart advantageous qualities to the resulting flour and dough related products produced therefrom. The present invention specifically relates to the fields of making flour and dough, used for totillas, corn chips, totilla chips, snacks, half-products and related products from the component parts and whole portions of cereal grains, and related materials.
Assemblages Of Breeding Birds As Indicators Of Grassland Condition, Sharon Freshman Browder, Douglas H. Johnson, I. J. Ball
Assemblages Of Breeding Birds As Indicators Of Grassland Condition, Sharon Freshman Browder, Douglas H. Johnson, I. J. Ball
United States Geological Survey, Northern Prairie Wildlife Research Center: Publications
We developed a measure of biological integrity for grasslands (GI) based on the most influential habitat types in the Prairie Pothole Region of North Dakota. GI is based on proportions of habitat types and the relationships of these habitat types to breeding birds. Habitat types were identified by digital aerial photography, verified on the ground, and quantified using GIS. We then developed an index to GI based on the presence or abundance of breeding bird species. Species abundance data were obtained from 3 min roadside point counts at 889 points in 44, 4050 ha study plots over a 2-year period. …
Leafy Spurge, R. M. Nowiersky, R. W. Pemberton
Leafy Spurge, R. M. Nowiersky, R. W. Pemberton
United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications
Leafy spurge, Euphorbia esula L., is an invasive, deep-rooted perennial herb that is native to Eurasia. The plant spreads through explosive seed release and vigorous lateral root growth, forming large, coalescing patches that can dominate rangeland, pastures, prairies and other non-crop areas in the Great Plains region of North America.
Spotted Knapweed, J. Story
Spotted Knapweed, J. Story
United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications
Spotted knapweed, Centaurea maculosa Lamarck, is a purple-flowered, herbaceous, perennial weed, living three to five years on average. It infests semiarid range lands in the western United States and roadsides and fields in the eastern part of the country. Infested areas are dominated by the plant, reducing their grazing value and suppressing native plant communities. The plant, originally from Central Asia, has been in North America for over 120 years.
Swallow-Worts, L. Tewksbury, R. Casagrande, A. Gassmann
Swallow-Worts, L. Tewksbury, R. Casagrande, A. Gassmann
United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications
There are three European species of swallow-worts found in North America: Vincetoxicum nigrum (L.) Moench (black swallow-wort), Vincetoxicum rossicum (Kleo.) Barb. (pale swallow-wort or dog strangling-vine), and Vincetoxicum hirundinaria Medik. (white swallow-wort) (Sheeley and Raynal, 1996). Swallow-worts are in the family Asclepiadaceae. Vincetoxicum nigrum and V. rossicum now are naturalized in northeastern North America, and both are invasive in natural areas and abandoned pastures (Lawlor, 2000). Swallow-worts are found in gardens and fields, along fencerows, roadways, grassy slopes, wooded edges, and streambanks. Tangled masses of swallow-wort vines shade and suppress native plants (Sheeley and Raynal, 1996). In Rhode Island, heavy …
Phylogenetic And Phenotypic Analysis Of Hiv Type 1 Env Gp120 In Cases Of Subtype C Mother-To-Child Transmission, Hong Zhang, Guillermo Ortí, Qiujiang Du, Jun He, Chipepo Kankasa, Ganapati Bhat, Charles Wood
Phylogenetic And Phenotypic Analysis Of Hiv Type 1 Env Gp120 In Cases Of Subtype C Mother-To-Child Transmission, Hong Zhang, Guillermo Ortí, Qiujiang Du, Jun He, Chipepo Kankasa, Ganapati Bhat, Charles Wood
Nebraska Center for Virology: Faculty Publications
Human immunodeficiency virus type 1 (HIV-1) subtype C constitutes a majority of the newly transmitted cases of HIV-1 in many developing countries. There is growing evidence suggesting that subtype C viruses may display characteristics that make them distinct from subtype B and other subtypes, and such differences may affect its transmission and pathogenesis in infected individuals. In this study, HIV-1 sequences from the C2–V4 region of the envelope gene were analyzed from four infected mother–infant pairs (MIPs) after perinatal transmission in Zambia. We found that all viral isolates from four Zambian MIPs were of the subtype C HIV-1 subgroup. All …
Effects Of Management Practices On Grassland Birds: Western Meadowlark, Jill A. Dechant, Marriah L. Sondreal, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Amy L. Zimmerman, Betty R. Euliss
Effects Of Management Practices On Grassland Birds: Western Meadowlark, Jill A. Dechant, Marriah L. Sondreal, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Amy L. Zimmerman, Betty R. Euliss
United States Geological Survey, Northern Prairie Wildlife Research Center: Publications
Western Meadowlark (Sturnella neglecta):
Breeding range
Suitable habitat
Area requirements
Brown-headed Cowbird brood parasitism
Breeding-season phenology and site fidelity
Species’ response to management
Management Recommendations
Habitat Characteristics
Effects Of Management Practices On Grassland Birds: Vesper Sparrow, Jill A. Dechant, Meghan F. Dinkins, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Betty R. Euliss
Effects Of Management Practices On Grassland Birds: Vesper Sparrow, Jill A. Dechant, Meghan F. Dinkins, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Betty R. Euliss
United States Geological Survey, Northern Prairie Wildlife Research Center: Publications
Upland Sandpiper (Pooecetes gramineus):
Breeding range
Suitable habitat
Area requirements
Brown-headed Cowbird brood parasitism
Breeding-season phenology and site fidelity
Species’ response to management
Management Recommendations
Habitat Characteristics
Effects Of Management Practices On Grassland Birds: Nelson’S Sharp-Tailed Sparrow, Jill A. Dechant, Marriah L. Sondreal, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Paul A. Rabie, Betty R. Euliss
Effects Of Management Practices On Grassland Birds: Nelson’S Sharp-Tailed Sparrow, Jill A. Dechant, Marriah L. Sondreal, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Paul A. Rabie, Betty R. Euliss
United States Geological Survey, Northern Prairie Wildlife Research Center: Publications
Nelson’s Sharp-Tailed Sparrow ( Ammodramus nelsoni nelsoni):
Breeding range
Suitable habitat
Area requirements
Brown-headed Cowbird brood parasitism
Breeding-season phenology and site fidelity
Species’ response to management
Management Recommendations
Habitat Characteristics
Immobilization Of Swift Foxes With Ketamine Hydrochloride-Xylazine Hydrochloride, Rebecca L. Telesco, Marsha A. Sovada
Immobilization Of Swift Foxes With Ketamine Hydrochloride-Xylazine Hydrochloride, Rebecca L. Telesco, Marsha A. Sovada
United States Geological Survey, Northern Prairie Wildlife Research Center: Publications
There is an increasing need to develop field immobilization techniques that allow researchers to handle safely swift foxes (Vulpes velox) with minimal risk of stress or injury. We immobilized captive swift foxes to determine the safety and effectiveness of ketamine hydrochloride and xylazine hydrochloride at different dosages. We attempted to determine appropriate dosages to immobilize swift foxes for an adequate field-handling period based on three anesthesia intervals (induction period, immobilization period, and recovery period) and physiologic responses (rectal temperature, respiration rate, and heart rate). Between October 1998–July 1999, we conducted four trials, evaluating three different dosage ratios of …
Effects Of Management Practices On Grassland Birds: Long-Billed Curlew, Jill A. Dechant, Marriah L. Sondreal, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Paul A. Rabie, Betty R. Euliss
Effects Of Management Practices On Grassland Birds: Long-Billed Curlew, Jill A. Dechant, Marriah L. Sondreal, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Paul A. Rabie, Betty R. Euliss
United States Geological Survey, Northern Prairie Wildlife Research Center: Publications
Long-Billed Curlew (Numenius americanus):
Breeding range
Suitable habitat
Area requirements
Brown-headed Cowbird brood parasitism
Breeding-season phenology and site fidelity
Species’ response to management
Management Recommendations
Habitat Characteristics
Genomewide Identification Of Proteins Secreted By The Hrp Type Iii Protein Secretion System Of Pseudomonas Syringae Pv. Tomato Dc3000, Tanja Petnicki-Ocwieja, David J. Schneider, Vincent C. Tam, Scott T. Chancey, Libo Shan, Yashitola Jamir, Lisa M. Schechter, Misty Janes, C. Robin Buell, Xiaoyan Tang, Alan Collmer, James R. Alfano
Genomewide Identification Of Proteins Secreted By The Hrp Type Iii Protein Secretion System Of Pseudomonas Syringae Pv. Tomato Dc3000, Tanja Petnicki-Ocwieja, David J. Schneider, Vincent C. Tam, Scott T. Chancey, Libo Shan, Yashitola Jamir, Lisa M. Schechter, Misty Janes, C. Robin Buell, Xiaoyan Tang, Alan Collmer, James R. Alfano
Department of Plant Pathology: Faculty Publications
The ability of Pseudomonas syringae pv. tomato DC3000 to be pathogenic on plants depends on the Hrp (hypersensitive response and pathogenicity) type III protein secretion system and the effector proteins it translocates into plant cells. Through iterative application of experimental and computational techniques, the DC3000 effector inventory has been substantially enlarged. Five homologs of known avirulence (Avr) proteins and five effector candidates, encoded by genes with putative Hrp promoters and signatures of horizontal acquisition, were demonstrated to be secreted in culture and/or translocated into Arabidopsis in a Hrp-dependent manner. These 10 Hrp-dependent outer proteins (Hops) were designated HopPtoC (Avr- PpiC2 …
The P23 Protein Of Citrus Tristeza Virus Controls Asymmetrical Rna Accumulation, Satyanarayana Tatineni, Siddarame Gowda, Maria A. Ayllon, Maria R. Albiach-Marti, Shailaja Rabindran, William O. Dawson
The P23 Protein Of Citrus Tristeza Virus Controls Asymmetrical Rna Accumulation, Satyanarayana Tatineni, Siddarame Gowda, Maria A. Ayllon, Maria R. Albiach-Marti, Shailaja Rabindran, William O. Dawson
Department of Plant Pathology: Faculty Publications
Citrus tristeza virus (CTV), a member of the Closteroviridae, has a 19.3-kb positive-stranded RNA genome that is organized into 12 open reading frames (ORFs) with the 10 3' genes expressed via a nested set of nine or ten 3'-coterminal subgenomic mRNAs (sgRNAs). Relatively large amounts of negative-stranded RNAs complementary to both genomic and sgRNAs accumulate in infected cells. As is characteristic of RNA viruses, wild-type CTV produced more positive than negative strands, with the plus-to-minus ratios of genomic and sgRNAs estimated at 10 to 20:1 and 40 to 50:1, respectively. However, a mutant with all of the 3' genes …
Influence Of Protein Tyrosine Kinases On Cell Volume Change-Induced Taurine Release, Herminia Pasantes-Morales, Rodrigo Franco
Influence Of Protein Tyrosine Kinases On Cell Volume Change-Induced Taurine Release, Herminia Pasantes-Morales, Rodrigo Franco
School of Veterinary and Biomedical Sciences: Faculty Publications
Taurine efflux occurs in association with cell swelling in both hyposmotic and isosmotic conditions and during cell shrinkage in apoptotic death. Release occurs through a leak pathway, is largely Ca2+-independent and is sensitive to Cl– channel blockers. Taurine efflux elicited by hyposmolarity is reduced or suppressed by tyrosine kinase blockers and increased by tyrosine phosphatase inhibitors. The specific kinases involved are still unknown and may be different in the various cell types. Non-receptor and scr-related protein kinases have been identified in some cells as elements that directly phosphorylate the taurine efflux pathway. Possible tyrosine kinase targets are …
Corn Yield Potential And Optimal Soil Productivity In Irrigated Corn/Soybean Systems, Achim R. Dobermann, Timothy J. Arkebauer, Kenneth G. Cassman, Rhae A. Drijber, J. Lindquist, S. Madhaven, John P. Markwell, Lenis Alton Nelson, James E. Specht, Daniel T. Walters, Haishun Yang, Brigid Amos, Darren L. Binder, C. Murphy, Gregory J. Teichmeier
Corn Yield Potential And Optimal Soil Productivity In Irrigated Corn/Soybean Systems, Achim R. Dobermann, Timothy J. Arkebauer, Kenneth G. Cassman, Rhae A. Drijber, J. Lindquist, S. Madhaven, John P. Markwell, Lenis Alton Nelson, James E. Specht, Daniel T. Walters, Haishun Yang, Brigid Amos, Darren L. Binder, C. Murphy, Gregory J. Teichmeier
Department of Agronomy and Horticulture: Faculty Publications
In 1999, an interdisciplinary research team at the University of Nebraska established a field experiment to (1) quantify and understand the yield potential of corn and soybean under irrigated conditions, (2) identify efficient crop management practices to achieve yields that approach potential levels, and (3) determine the energy use efficiency, global warming and soil C-sequestration potential of intensively managed corn systems. The experiment compares systems that represent different levels of management intensity expressed as combinations of crop rotation (continuous corn, corn-soybean), plant density (low, medium, high) and nutrient management (recommended best management vs. intensive management). Detailed measurements include soil nutrient …
Crop Sequence And Nitrogen Fertilization Effects On Soil Properties In The Western Corn Belt, M. A. Liebig, Gary E. Varvel, John W. Doran, Brian J. Wienhold
Crop Sequence And Nitrogen Fertilization Effects On Soil Properties In The Western Corn Belt, M. A. Liebig, Gary E. Varvel, John W. Doran, Brian J. Wienhold
Department of Agronomy and Horticulture: Faculty Publications
Understanding long-term management effects on soil properties is necessary to determine the relative sustainability of cropping systems. Soil physical, chemical, and biological properties were measured in a long-term cropping system study in the Western Corn Belt. Properties were evaluated after 16 yr in four crop sequences [continuous corn (Zea mays L.) (CC), corn–soybean [Glycine max. (L.)] (C–SB), corn–oat (Avena sativa L.) + clover (80% sweet clover [Melilotus officinalis L.] and 20% red clover [Trifolium pratense L.])–grain sorghum [(Sorghum bicolor (L.) Moench)–soybean (C–OCL–SG– SB), and corn–soybean-grain sorghum–oat + clover (C–SB–SG– OCL)] each at three …
Critical Period For Weed Control: The Concept And Data Analysis, Stevan Z. Knezevic, Sean P. Evans, Erin E. Blankenship, Rene C. Van Acker, John L. Lindquist
Critical Period For Weed Control: The Concept And Data Analysis, Stevan Z. Knezevic, Sean P. Evans, Erin E. Blankenship, Rene C. Van Acker, John L. Lindquist
Department of Agronomy and Horticulture: Faculty Publications
The critical period for weed control (CPWC) is a period in the crop growth cycle during which weeds must be controlled to prevent yield losses. Knowing the CPWC is useful in making decisions on the need for and timing of weed control and in achieving efficient herbicide use from both biological and economic perspectives. An increase in the use of herbicide-tolerant crops, especially soybean resistant to glyphosate, has stimulated interest in the concept of CPWC. Recently, several studies examined this concept in glyphosate-resistant corn and soybean across the midwestern United States. However, these studies presented various methods for data analysis …
Growth Response Of Velvetleaf To Three Postemergence Herbicides, Cheryl A. Murphy, John L. Lindquist
Growth Response Of Velvetleaf To Three Postemergence Herbicides, Cheryl A. Murphy, John L. Lindquist
Department of Agronomy and Horticulture: Faculty Publications
Knowledge of how reduction in the rate of herbicide application or rotation of their mode of action influences weed growth will provide insight into how successful these practices will be in an integrated weed management program. Field experiments were conducted in 1996 and 1997 to quantify velvetleaf growth response to three postemergence herbicides, each with a different mode of action. A monoculture of velvetleaf was treated with halosulfuron, dicamba, and flumiclorac at 0, 0.10, 0.25, 0.50, 0.75, and 1.0 X the labeled rate for weed control in corn. Percent plant mortality increased with rate of application; the greatest mortality occurred …
Genetic Analysis Of Feed Quality And Seed Weight Of Sorghum Inbred Lines And Hybrids Using Analytical Methods And Nirs, C. Hicks, M. R. Tuinstra, Jeffrey F. Pedersen, F. E. Dowell, K. D. Kofoid
Genetic Analysis Of Feed Quality And Seed Weight Of Sorghum Inbred Lines And Hybrids Using Analytical Methods And Nirs, C. Hicks, M. R. Tuinstra, Jeffrey F. Pedersen, F. E. Dowell, K. D. Kofoid
Department of Agronomy and Horticulture: Faculty Publications
Eight lines of grain sorghum and their F1 hybrids were evaluated for contents of crude protein (CP), fat (FAT), and starch (STA); protein digestibility (PD); and in vitro dry matter disappearance (IVDMD). The effect of seed weight (SW) on these traits and the potential use of near infrared reflectance spectroscopy (NIRS) to predict them also were investigated. The male lines included three normal-seeded lines (TX2737, TX435, and P954063) and two largeseeded lines (PL-1 and Eastin1). The female lines included commonU.S. seed parent lines (Wheatland, Redlan, and SA3042). The lines and their hybrids were grown under dryland conditions at Kansas State …
Combinatorial Control Of Yeast Fet4 Gene Expression By Iron, Zinc, And Oxygen, Brian M. Waters, David J. Eide
Combinatorial Control Of Yeast Fet4 Gene Expression By Iron, Zinc, And Oxygen, Brian M. Waters, David J. Eide
Department of Agronomy and Horticulture: Faculty Publications
Acquisition of metals such as iron, copper, and zinc by the yeast Saccharomyces cerevisiae is tightly regulated. High affinity uptake systems are induced under metal-limiting conditions to maintain an adequate supply of these essential nutrients. Low affinity uptake systems function when their substrates are in greater supply. The FET4 gene encodes a low affinity iron and copper uptake transporter. FET4 expression is regulated by several environmental factors. In this report, we describe the molecular mechanisms underlying this regulation. First, we found that FET4 expression is induced in iron-limited cells by the Aft1 iron-responsive transcriptional activator. Second, FET …
A Physically Based Two-Dimensional Infiltration Model For Furrow Irrigation, Christopher J. Skonard, Derrel L. Martin
A Physically Based Two-Dimensional Infiltration Model For Furrow Irrigation, Christopher J. Skonard, Derrel L. Martin
Department of Agricultural and Biological Systems Engineering: Presentations and White Papers
A two-dimensional physically based infiltration model was developed for furrow
irrigation. Infiltration was simulated using the Green-Ampt infiltration method. The Green-Ampt infiltration parameters are available from numerous sources, unlike the Kostiakov infiltration parameters. Simulation tests showed the two-dimensional model capable of estimating cumulative infiltration volume within 8% compared to simulated infiltration using the finite element model, Hydrus-2D. Application of the two-dimensional model in a surface irrigation advance model allows irrigation performance parameters to be predicted without extensive soil experiments.
Impact Of Manure Application On Phosphorus Runoff And Soil Erosion, Daniel T. Walters, C. Gossin, Gregory J. Teichmeier, Galen E. Erickson
Impact Of Manure Application On Phosphorus Runoff And Soil Erosion, Daniel T. Walters, C. Gossin, Gregory J. Teichmeier, Galen E. Erickson
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Phosphorus (P) losses from agricultural land is a serious environmental issue because of the impact of P on freshwater eutrophication (McDowell, et al., 2001). The movement of P from soil to surface water is impacted by P input to soil and manure management practices that impact P transport processes. Twenty-one natural runoff plots were established to monitor the effect of time and method of composted beef feedlot manure application and feed P input on net losses of bio-available P and sediment in surface runoff. Reducing feed P inputs resulted in a 33% reduction in manure P content. Runoff losses of …
‘Neuroecologists’ Are Not Made Of Straw, Robert R. Hampton, Susan D. Healy, Sara J. Shettleworth, Alan Kamil
‘Neuroecologists’ Are Not Made Of Straw, Robert R. Hampton, Susan D. Healy, Sara J. Shettleworth, Alan Kamil
Papers in Behavior in Biological Sciences
In the October issue of Trends in Cognitive Sciences, Bolhuis and Macphail criticized the functional/evolutionary approach to the neural mechanisms of learning and memory, and concluded that the approach is ‘often misleading and might provide us with the wrong answers’ [1]. Their critique touches on a number of interesting issues, and provides a useful prompt to examine the role of an adaptationist approach to the study of cognition. In their effort to stimulate discussion, however, Bolhuis and Macphail have overstated positions they attribute to ‘neuroecologists’.
Spatial And Social Cognition In Corvids: An Evolutionary Approach, Russell P. Balda, Alan Kamil
Spatial And Social Cognition In Corvids: An Evolutionary Approach, Russell P. Balda, Alan Kamil
Papers in Behavior in Biological Sciences
The central research questions that have guided our studies since 1981 combine issues and techniques from both comparative psychology and avian ecology. Most of our questions originate from the cognitive implications of extensive field studies on the natural history, ecology, and behavior of seed-caching corvids. Because our questions have evolved as our studies progressed, we have chosen to give a historical perspective outlining the progression of our ideas and questions.