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Test 1702s - S190: New Holland 3930 8x8 Diesel, Nebraska Tractor Test Lab Jan 1998

Test 1702s - S190: New Holland 3930 8x8 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

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Nebraska Summary: S326 Case-Ih C70, Nebraska Tractor Test Lab Jan 1998

Nebraska Summary: S326 Case-Ih C70, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

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Nebraska Summary: S295 New Holland Ts 100, Nebraska Tractor Test Lab Jan 1998

Nebraska Summary: S295 New Holland Ts 100, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

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Nebraska Summary: S329 Case-Ih C100, Nebraska Tractor Test Lab Jan 1998

Nebraska Summary: S329 Case-Ih C100, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

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Nebraska Summary: S327 Case-Ih C80, Nebraska Tractor Test Lab Jan 1998

Nebraska Summary: S327 Case-Ih C80, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

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Nebraska Summary: S445 Zetor 10741, Nebraska Tractor Test Lab Jan 1998

Nebraska Summary: S445 Zetor 10741, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

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Nebraska Summary: S502 Kubota M9000dt, Nebraska Tractor Test Lab Jan 1998

Nebraska Summary: S502 Kubota M9000dt, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

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Arthropods On Pine Foliage In Urban Landscapes, Mary Ellen Dix, Frederick P. Baxendale Jan 1998

Arthropods On Pine Foliage In Urban Landscapes, Mary Ellen Dix, Frederick P. Baxendale

Department of Entomology: Faculty Publications

Urban landscapes are dense heterogenous matrices composed of turf broken up by tree patches or corridors (Forman and Godron, 1986, Landscape ecology. John Wiley, NY). Trees and their associated understory vegetation in the urban landscape provide food and protective habitat for many arthropods and their natural enemies and increase biological and spatial diversity (Andow, 1991, Annu. Rev. Entomol. 36:561-586). Pest management strategies that enhance the abundance of natural predator populations are alternatives to chemical pesticides. The goal of this research was to obtain essential baseline information on pine trees in turf landscapes by identifying common families or classes of arthropod …

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Susceptibility Of House Fly (Diptera: Muscidae) Larvae To Entomopathogenic Nematodes (Rhabditida: Heterorhabditidae, Steinernematidae), David B. Taylor, Allen L. Szalanski, Byron J. Adams, Richard D. Peterson Ii Jan 1998

Susceptibility Of House Fly (Diptera: Muscidae) Larvae To Entomopathogenic Nematodes (Rhabditida: Heterorhabditidae, Steinernematidae), David B. Taylor, Allen L. Szalanski, Byron J. Adams, Richard D. Peterson Ii

Department of Entomology: Faculty Publications

The potential for entomopathogenic nematodes to control flies in cattle feedlots was determined by screening 40 strains representing 8 species of Heterorhabditis Poinar and 5 species of Steinemema Travassos for virulence toward 3rd-instar house flies (maggots), Musca domestica L. None of the 22 strains of Heterorhabditis infecting maggots caused significant levels of mortality in a filter paper assay. Ten strains of Steinemema infected maggots, of which 7 strains (4 S. carpocapsae (Weiser), 2 S.feltiae (Filipjev), and 1 S. scapterisci Nguyen & Smart) caused significant mortality. Ten Heterorhabditis strains and 10 Steinemema strains successfully reproduced for ≥ 2 generations in maggots. …

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Parasitoids Recovered From European Corn Borer, Ostrinia Nubilalis Hübner, (Lepidoptera: Pyralidae) Larvae In Nebraska, Thomas L. Clark, John E. Foster, John F. Witkowski, Blair D. Siegfried, Terence A. Spencer Jan 1998

Parasitoids Recovered From European Corn Borer, Ostrinia Nubilalis Hübner, (Lepidoptera: Pyralidae) Larvae In Nebraska, Thomas L. Clark, John E. Foster, John F. Witkowski, Blair D. Siegfried, Terence A. Spencer

Department of Entomology: Faculty Publications

Information about the current status of parasitoids attacking European com borer, Ostrinia nubilalis (Hübner). larvae is lacking in Nebraska. This study was conducted at multiple sites in 5 counties during 1995 and 1996 to determine the presence and prevalence of European com borer parasitoids in Eastern Nebraska. The braconid, Macrocentrus grandii Goidanich. was recovered from 8.9 and 10.2% of collected 5th instar European com borer larvae during 1995 and 1996, respectively. Recovery of this parasitoid had not been previously reported in Nebraska. Meanwhile. the ichneumonid, Eriborus terebrans (Gravenhorst), was recovered from 7.6 and 7.5% of collected larvae during the same …

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Entomology In The Developing World, Elvis A. Heinrichs Jan 1998

Entomology In The Developing World, Elvis A. Heinrichs

Department of Entomology: Faculty Publications

The global population continues to increase at an alarming rate, with 90% of the added population, or 85 million per year, occurring in the developing nations of the world. From 1950 to 1980, world food production doubled, with increases in the developing countries exceeding that of the developed countries. However, food production was not able to keep pace with the population in the developing world, where population increases were twice the rate of those in the developed world. Increases in per capita food production since the 1950s have been only one-third of the developed world because increased food production has …

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Interpreting Carnivore Scent-Station Surveys, Glen A. Sargeant, Douglas H. Johnson, William E. Berg Jan 1998

Interpreting Carnivore Scent-Station Surveys, Glen A. Sargeant, Douglas H. Johnson, William E. Berg

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

The scent-station survey method has been widely used to estimate trends in carnivore abundance. However, statistical properties of scent-station data are poorly understood, and the relation between scent- station indices and carnivore abundance has not been adequately evaluated. We assessed properties of scent- station indices by analyzing data collected in Minnesota during 1986-93. Visits to stations separated by < 2 km were correlated for all species because individual carnivores sometimes visited several stations in succession. Thus, visits to stations had an intractable statistical distribution. Dichotomizing results for lines of 10 stations (0 or ≥ 1 visits) produced binomially distributed data that were robust to multiple visits by individuals. We abandoned 2-way comparisons among years in favor of tests for population trend, which are less susceptible to bias, and analyzed results separately for biogeographic sections of Minnesota because trends differed among sections. Before drawing inferences about carnivore population trends, we reevaluated published validation experiments. Results implicated low statistical power and confounding as possible explanations for equivocal or conflicting results of validation efforts. Long-term trends in visitation rates probably reflect real changes in populations, but poor spatial and temporal resolution, susceptibility to confounding, and low statistical power limit the usefulness of this survey method.

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A Phylogenetic Analysis Of Heterorhabditis (Nemata: Rhabditidae) Based On Internal Transcribed Spacer 1 Dna Sequence Data, B. J. Adams, A. M. Burnell, Thomas O. Powers Jan 1998

A Phylogenetic Analysis Of Heterorhabditis (Nemata: Rhabditidae) Based On Internal Transcribed Spacer 1 Dna Sequence Data, B. J. Adams, A. M. Burnell, Thomas O. Powers

Department of Plant Pathology: Faculty Publications

Internal transcribed spacer 1 sequences were used to infer phylogenetic relationships among 8 of the 9 described species and one putative species of the entomopathogenic nematode genus Heterorhabditis. Sequences were aligned and optimized based on pairwise genetic distance and parsimony criteria and subjected to a variety of sequence alignment parameters. Phylogenetic trees were constructed with maximum parsimony, cladistic, distance, and maximum likelihood algorithms. Our results gave strong support for four pairs of sister species, while relationships between these pairs also were resolved but less well supported. The ITS1 region of the nuclear ribosomal repeat was a reliable source of …

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Peanut Yellow Spot Virus Is A Member Of A New Serogroup Of Tospovirus Genus Based On Small (S) Rna Sequence And Organization, Satyanarayana Tatineni, S. Gowda, K. Lakshminarayana Reddy, S. E. Mitchell, W. O. Dawson, D. V. R. Reddy Jan 1998

Peanut Yellow Spot Virus Is A Member Of A New Serogroup Of Tospovirus Genus Based On Small (S) Rna Sequence And Organization, Satyanarayana Tatineni, S. Gowda, K. Lakshminarayana Reddy, S. E. Mitchell, W. O. Dawson, D. V. R. Reddy

Department of Plant Pathology: Faculty Publications

Peanut yellow spot virus (PYSV) represents a distinct tospovirus species based on serology and nucleic acid hybridization. The sequence of the S RNA was 2 970 nucleotides with 22 nucleotide long inverted repeats (with three mismatches) at the termini. The coding was ambisense with a long open reading frame (ORF) in each strand. The 5'-large ORF (1 440 nucleotides in the viral sense (v) strand) encoded a protein with a predicted size of 53.2 kDa that was identified as the nonstructural (NSs) protein based on 16–21% sequence identity and 42– 48% sequence similarity with other tospoviruses. A 3' ORF (741 …

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Polyadenylation Of Vesicular Stomatitis Virus Mrna Dictates Efficient Transcription Termination At The Intercistronic Gene Junctions, Leroy N. Hwang, Nathan Englund, Asit K. Pattnaik Jan 1998

Polyadenylation Of Vesicular Stomatitis Virus Mrna Dictates Efficient Transcription Termination At The Intercistronic Gene Junctions, Leroy N. Hwang, Nathan Englund, Asit K. Pattnaik

School of Veterinary and Biomedical Sciences: Faculty Publications

The intercistronic gene junctions of vesicular stomatitis virus (VSV) contain conserved sequence elements that are important for polyadenylation and transcription termination of upstream transcript as well as reinitiation of transcription of downstream transcript. To examine the role of the putative polyadenylation signal 3' AUACU75' at the gene junctions in polyadenylation and transcription termination, we constructed plasmids encoding antigenomic minireplicons containing one or two transcription units. In plasmid-transfected cells, analyses of the bicistronic minireplicon containing the wild-type or mutant intercistronic gene junctions for the ability to direct synthesis of polyadenylated upstream, downstream, and readthrough mRNAs showed that the AUACU …

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Selective And Organotypic Culture Of Intrahepatic Bile Duct Cells From Adult Pig Liver, Neil C. Talbot, Thomas J. Caperna Jan 1998

Selective And Organotypic Culture Of Intrahepatic Bile Duct Cells From Adult Pig Liver, Neil C. Talbot, Thomas J. Caperna

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

Secondary culture of nontransformed bile duct epithelium has been difficult to achieve. STO feeder cell-dependent secondary cultures of adult pig bile duct cells were established from primary cultures of adult pig liver cells. Adult pig hepatocytes exhibited limited or no replication and were lost from the secondary culture at Passage 3 or 4. In contrast, adult pig bile duct cells replicated and were carried for 4-8 passages in secondary culture. A simple method to produce nearly pure pig intrahepatic bile duct cultures was first to freeze a relatively crude liver cell preparation. Upon subsequent thawing, all hepatocytes and most macrophages …

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Estimates Of Annual Survival Probabilities For Adult Florida Manatees (Trichechus Manatus Latirostris), C. A. Langtimm, T. J. O'Shea, R. Pradel, C. A. Beck Jan 1998

Estimates Of Annual Survival Probabilities For Adult Florida Manatees (Trichechus Manatus Latirostris), C. A. Langtimm, T. J. O'Shea, R. Pradel, C. A. Beck

United States Geological Survey: Staff Publications

The population dynamics of large, long-lived mammals are particularly sensitive to changes in adult survival. Understanding factors affecting survival patterns is therefore critical for developing and testing theories of population dynamics and for developing management strategies aimed at preventing declines or extinction in such taxa. Few studies have used modern analytical approaches for analyzing variation and testing hypotheses about survival probabilities in large mammals. This paper reports a detailed analysis of annual adult survival in the Florida manatee (Trichechus manatus latirostris), an endangered marine mammal, based on a mark-recapture approach. Natural and boat- inflicted scars distinctively "marked" individual …

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The ‘‘Foliage Is The Fruit’’ Hypothesis: Complex Adaptations In Buffalograss (Buchloe Dactyloides), John Ortmann, Walter H. Schacht, James L. Stubbendieck, Dennis R. Brink Jan 1998

The ‘‘Foliage Is The Fruit’’ Hypothesis: Complex Adaptations In Buffalograss (Buchloe Dactyloides), John Ortmann, Walter H. Schacht, James L. Stubbendieck, Dennis R. Brink

Department of Agronomy and Horticulture: Faculty Publications

Buffalograss (Buchloe dactyloides) has been described as an excellent fit for Janzen’s ‘‘Foliage is the Fruit’’ (FF) hypothesis, which suggests that large grazing animals ingest and later disperse seeds of some herbs when consuming their foliage. We tested this hypothesis by feeding buffalograss burs and legume seeds to ruminally fistulated beef steers. Our objectives were to determine (1) rumen residence times of buffalograss burs, free buffalograss caryopses and legume seeds; (2) total tract residence times for the three types of propagules; (3) percentage propagule survival after passage and (4) germinability of fed and unfed burs and caryopses. Bur …

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Expression Of A Heterologous Polypeptide In Mammary Tissue Of Transgenic Non-Human Mammals Using Along Whey Acdic Protein Promoter, Henryk Lubon, William N. Drohan, Lother Hennighausen Jan 1998

Expression Of A Heterologous Polypeptide In Mammary Tissue Of Transgenic Non-Human Mammals Using Along Whey Acdic Protein Promoter, Henryk Lubon, William N. Drohan, Lother Hennighausen

Department of Chemical and Biomolecular Engineering: Faculty Publications

Heterologous polypeptides are produced in the milk of transgenic non-human mammals by the expression of a Stably integrated DNA sequence containing the long whey acidic protein promoter operably linked to a DNA sequence encoding a heterologous polypeptide and a signal Sequence. The transgenic non-human mammals of the present invention are produced by introducing this DNA sequence Such that the DNA sequence is stably integrated into the DNA of germ line cells of the mature mammal and inherited in normal Mendelian fashion. A representative heterologous polypeptide is protein C.

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Growth Traits Among Sorghum Genotypes In Response To Aluminum, J. H. Bernal, R. B. Clark Jan 1998

Growth Traits Among Sorghum Genotypes In Response To Aluminum, J. H. Bernal, R. B. Clark

Department of Agronomy and Horticulture: Faculty Publications

Aluminum (Al) has many detrimental effects on plant growth, and shoots and roots are normally affected differently. A study was conducted to determine differences among sorghum [Sorghum bicolor (L.) Moench] genotypes with broad genetic backgrounds for growth traits of plants grown at 0,200,400,600, and 800 uM Al in nutrient solutions (pH 4.0). Genotypes were categorized into "Al-sensitive", "intermediate Al-tolerant", "Al-tolerant", and SC 283 (an Al-tolerant standard). As Al increased, shoot and root dry matter (DM), net main axis root length (NMARL), and total root length (TRL) became lower than controls (0 Al). Aluminum toxicity and/or nutrient deficiency symptoms become …

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Design Of Tapered Augers For Uniform Unloading Particulate Material From Rectangular Cross-Section Containers, M. S. Burr, Michael F. Kocher, David D. Jones Jan 1998

Design Of Tapered Augers For Uniform Unloading Particulate Material From Rectangular Cross-Section Containers, M. S. Burr, Michael F. Kocher, David D. Jones

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The design equation for an auger to provide uniform unloading of particulate material from a container with a rectangular cross-section (Jones and Kocher, 1995) was revised to account for the minimum flighting height that could effectively unload particles with a known average smallest diameter. A minimum flighting height that was about 64% of the average smallest diameter of the particles was experimentally determined to obtain mean slopes of the top surface of the material not significantly different from zero for screened soybeans. A linear taper that best fit the square root curve for the inside diameter of the auger was …

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Matrix-Enhanced Calibration Procedure For Multivariate Calibration Models With Near-Infrared Spectra, Mark R. Riley, Mark A. Arnold, David W. Murhammer Jan 1998

Matrix-Enhanced Calibration Procedure For Multivariate Calibration Models With Near-Infrared Spectra, Mark R. Riley, Mark A. Arnold, David W. Murhammer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A novel method is introduced for developing calibration models for the spectroscopic measurement of chemical concentrations in an aqueous environment. To demonstrate this matrix-enhanced calibration procedure, we developed calibration models to quantitate glucose and glutamine concentrations in an insect cell culture medium that is a complex mixture of more than 20 components, with three components that manifest significant concentration changes. Accurate calibration models were generated for glucose and glutamine by using a calibration data set composed of 60 samples containing the analytes dissolved in an aqueous buffer along with as few as two samples of the analytes dissolved in culture …

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The Ecology And Evolution Of Spatial Memory In Corvids Of The Southwestern Usa: The Perplexing Pinyon Jay, Russell P. Balda, Alan Kamil Jan 1998

The Ecology And Evolution Of Spatial Memory In Corvids Of The Southwestern Usa: The Perplexing Pinyon Jay, Russell P. Balda, Alan Kamil

Papers in Behavior in Biological Sciences

The corvids of the southwest possess many adaptations for the harvest, transport, caching and recovery of pine seeds. However, there is a large degree of between-species variation in the distribution of these traits. These corvids have a well-accepted phylogeny (Hope, 1989), live within close proximity to one another and have relatively well-known natural histories. They therefore present an excellent opportunity to apply the comparative method (Kamil, 1988) to the study of these species differences (Balda et al., 1997). The comparative method for the study of adaptation and evolution of behavioral traits begins with a careful study of the natural histories …

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On The Proper Definition Of Cognitive Ethology, Alan Kamil Jan 1998

On The Proper Definition Of Cognitive Ethology, Alan Kamil

Papers in Behavior in Biological Sciences

The last 20-30 years have seen two “scientific revolutions” in the study of animal behavior: the cognitive revolution that originated in psychology, and the Darwinian, behavioral ecology revolution that originated in biology. Among psychologists, the cognitive revolution has had enormous impact. Similarly, among biologists, the Darwinian revolution has had enormous impact. The major theme of this chapter is that these two scientific research programs need to be combined into a single approach, simultaneously cognitive and Darwinian, and that this single approach is most appropriately called cognitive ethology.

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Preface: Animal Cognition In Nature, Russell P. Balda, Irene M. Pepperberg, Alan Kamil Jan 1998

Preface: Animal Cognition In Nature, Russell P. Balda, Irene M. Pepperberg, Alan Kamil

Papers in Behavior in Biological Sciences

This volume, Animal Cognition in Nature, is the result of an ongoing synthesis of several ideas that were considered revolutionary, if not heretical, in the 1960s. At that time, animal behavior, whether studied in field or laboratory, by ethologists or psychologists, was generally interpreted as the result of simple processes relating specific stimuli to specific behaviors. Examples from that time include S–R models, sign stimuli, IRMs, etc. Theoretical constructs such as mental representations, memory or attention were avoided. Today, students of animal behavior work in an entirely different atmosphere. This is the result of several developments.

One of these developments …

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Telomerase Expression In Chickens: Constitutive Activity In Somatic Tissues And Down-Regulation In Culture, Ranga N. Venkatesan, Carolyn Price Jan 1998

Telomerase Expression In Chickens: Constitutive Activity In Somatic Tissues And Down-Regulation In Culture, Ranga N. Venkatesan, Carolyn Price

Department of Biochemistry: Faculty Publications

Although human and rodent telomeres have been studied extensively, very little is known about telomere dynamics in other vertebrates. Moreover, our current dependence on mice as a model for human tumorigenesis and aging poses a problem because human and mouse telomere biology is very different. To explore whether chickens might provide a more useful model, we have examined telomerase activity and telomere length in chicken tissues as well as in primary cell cultures. Although chicken telomeres resemble human telomeres in that they are 8–20 kb in length, the distribution of telomerase activity in chickens resembles what is found in mice. …

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Purification And Characterization Of A Soybean Root Nodule Phosphatase Expressed In Pichia Pastoris, Alan R. Penheiter, Robert V. Klucas, Gautam Sarath Jan 1998

Purification And Characterization Of A Soybean Root Nodule Phosphatase Expressed In Pichia Pastoris, Alan R. Penheiter, Robert V. Klucas, Gautam Sarath

Gautam Sarath Publications

Soybean root nodules possess a developmentally regulated acid phosphatase (ACP) that exhibits the highest specificity for purine 5’-nucleoside monophosphates. The enzyme is a glycosylated dimer of 28- and 31-kDa subunits, which appear to be products of the same gene but differ in posttranslational modifications. In order to perform directed mutagenesis and more extensive biochemical characterization, a means of producing recombinant ACP was needed. Several attempts were made to express ACP in Escherichia coli, but all conditions employed resulted in protein that was found entirely in inclusion bodies, and resolubilization experiments were unsuccessful. Therefore, the methyltrophic yeast Pichia pastoris was …

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Differential Gene Expression In Insects: Transcriptional Control, Lawrence G. Harshman, Anthony A. James Jan 1998

Differential Gene Expression In Insects: Transcriptional Control, Lawrence G. Harshman, Anthony A. James

School of Biological Sciences: Faculty Publications

Studies on transcriptional control of gene expression play a pivotal role in many areas of biology. In non-Drosophilid insects, the cuticle, chorion, immune response, silk gland, storage proteins, and vitellogenin are foci for advances in basic research on promoter elements and transcription factors. Insects offer other advantages for gene regulation studies, including the availability of applied problems. In non-Drosophilid insects, the most serious problem for transcriptional control studies is the lack of homologous in vivo expression systems. Once this deficiency is addressed, the full impact of research on transcription control will be realized throughout the field of entomology.

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Life-History Decisions Under Predation Risk: Importance Of A Game Perspective, Amos Bouskila, Michael E. Robinson, Bernard D. Roitberg, Brigitte Tenhumberg Jan 1998

Life-History Decisions Under Predation Risk: Importance Of A Game Perspective, Amos Bouskila, Michael E. Robinson, Bernard D. Roitberg, Brigitte Tenhumberg

School of Biological Sciences: Faculty Publications

We model ontogenetic shifts (e.g. in food or habitat use) during development under predation risk. We ask whether inclusion of state and frequency dependence will provide new insights when compared with game-free life-history theory. We model a simple biological scenario in which a prey animal must switch from a low-predation, low-growth habitat to a high-predation, high-growth habitat. To assess the importance of frequency dependence, we compare the results of four scenarios of increasing complexity: (1) no predation; (2) constant predation; (3) frequency-dependent predation (predation risk diluted at high prey density); and (4) frequency-dependent predation as in (3) but with predators …

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Population Biology Of Intraspecific Polyploidy In Grasses, Kathleen H. Keeler Jan 1998

Population Biology Of Intraspecific Polyploidy In Grasses, Kathleen H. Keeler

School of Biological Sciences: Faculty Publications

Polyploidy is the duplication of an entire nuclear genome, whether diploid or higher level (Stebbins, 1971; Thompson and Lumaret, 1992) and a frequent occurrence in plants. Stebbins (1971) estimated that 30-35% of flowering plant species are polyploid, and that many more had a polyploid event in their evolutionary history, including all members of such important families as the Magnoliaceae, Salicaceae, and Ericaceae. Goldblatt (1980) estimated 55%, but probably up to 75%, of monocotyledons had at least one polyploid event in their history, using the criterion that if the species has a base number higher than n = 13 it is …

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