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1987

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Articles 1 - 30 of 1759

Full-Text Articles in Life Sciences

Ec88-116 Universal Soil Loss Equation: A Handbook For Nebraska Producers, A. J. Jones, D. Walters, W. G. Hance, Elbert C. Dickey, J.R. Culver Dec 1987

Ec88-116 Universal Soil Loss Equation: A Handbook For Nebraska Producers, A. J. Jones, D. Walters, W. G. Hance, Elbert C. Dickey, J.R. Culver

Historical Materials from University of Nebraska-Lincoln Extension

Tons of soil are lost from agricultural fields in Nebraska each year as a result of water erosion. The accelerated loss of topsoil reduces the availability of plant nutrients and water needed for optimum crop production. In addition, the eroded soil frequently moves into surface waters causing sediment to be deposited in streams and reservoirs and nutrients to be released into other biological systems. The purposes of this workbook are to provide an understandng of how soil erosion estimates are determined, to estimate erosion control resulting from numerous cropping systems, and to inform the producer of alternative practices which may ...


Overview Of Physical Studies Of Bulk Water In Biopolymers, Wm. Negendank Dec 1987

Overview Of Physical Studies Of Bulk Water In Biopolymers, Wm. Negendank

Scanning Microscopy

The Symposium of which this paper is a part, "The State Of Water In The Cell", examines evidence which indicates that the bulk water of the cell has physical properties that are different from those of free water in a dilute aqueous solution. The heterogeneity of environments of water within cells makes direct application of physical studies difficult. However, the major physiologic effect of an ordered state of bulk cell water is solute exclusion, and this is also demonstrated by simple polymer solutions. Such systems have provided an opportunity to show that such water has motional correlation times within an ...


Fibroblast And Epidermal Cell-Type I Collagen Interactions: Cell Culture And Human Studies, Charles J. Doillon, Frederick H. Silver, Robert M. Olson, Chandrakala Y. Kamath, Richard A. Berg Dec 1987

Fibroblast And Epidermal Cell-Type I Collagen Interactions: Cell Culture And Human Studies, Charles J. Doillon, Frederick H. Silver, Robert M. Olson, Chandrakala Y. Kamath, Richard A. Berg

Scanning Microscopy

Fibroblast and epidermal cell-type I collagen sponge interactions were studied in cell culture as well as in humans. In cell culture, fibroblasts were observed to migrate and proliferate throughout a type I collagen sponge containing either hyaluronic acid (HA) or fibronectin (FN). Fibroblasts accumulated in the center of the pores in sponges containing HA and appeared to surround themselves with newly synthesized extracellular matrix. In sponges containing FN, fibroblasts attached to and elongated along the collagen fibers of the sponge. In the absence of FN or HA protein synthesis of fibroblasts appeared to be inhibited by the presence of the ...


The Role Of Scanning Electron Microscopy In Periodontal Research, A. Carrassi, S. Abati, G. Santarelli Dec 1987

The Role Of Scanning Electron Microscopy In Periodontal Research, A. Carrassi, S. Abati, G. Santarelli

Scanning Microscopy

During recent years a great amount of research has led to a better understanding of the etiology, pathogenesis and pattern of progression of periodontal diseases. Scanning electron microscopy (SEM) has contributed to this improvement, mainly with respect to histology of periodontal tissues, the description of the morphology and distribution of bacteria on the exposed root surface, analysis of the host-parasite interactions on the gingival pocket wall, and morphological evaluation of root treatment. This review deals with all these topics. Unusual types of SEM research are also described and discussed. Uncommon sample preparation techniques for SEM in periodontal research are described ...


Nucleotide Sequence And Characterization Of The Transcript Of A Dictyostelium Ribosomal Protein Gene, Laura F. Steel, A. Smyth, Allan Jacobson Dec 1987

Nucleotide Sequence And Characterization Of The Transcript Of A Dictyostelium Ribosomal Protein Gene, Laura F. Steel, A. Smyth, Allan Jacobson

Open Access Publications by UMMS Authors

Dictyostelium ribosomal protein mRNAs are subject to developmental regulation of both their translation and their stability. In order to consider whether such post-transcriptional regulation can be attributed to structural features of the mRNAs, we have cloned and sequenced a 1.9 kb EcoRI genomic DNA fragment which contains the gene for the Dictyostelium ribosomal protein 1024 (rp1024). The rp1024 gene contains a single intron of 350 bp which begins just after the fourth codon of protein coding sequence. Transcription begins 11 to 28 bp upstream from the initiator ATG in a pyrimidine rich region which is preceded by an oligo ...


The Cell Water Problem Posed By Electron Microscopic Studies Of Ion Binding In Muscle, L. Edelmann Dec 1987

The Cell Water Problem Posed By Electron Microscopic Studies Of Ion Binding In Muscle, L. Edelmann

Scanning Microscopy

The question whether cell K+ is free or bound in the striated frog muscle has been investigated during the last 10 years by different cryomethods and electron microscopy. The results support the view that most of cellular ions are osmotically inactive and that therefore the observed cell water activity must be explained by a model which assumes a specific cell water structure. According to the association-induction hypothesis, cell water is influenced by macromolecules and has low solubilities for Na+ and other solutes which therefore are partly excluded from cellular water. Autoradiography of frozen hydrated Na+ loaded muscles and microanalytical studies ...


Microvascular Casting Of The Lung: Vascular Lavage, Dean E. Schraufnagel, Aloisia Schmid Dec 1987

Microvascular Casting Of The Lung: Vascular Lavage, Dean E. Schraufnagel, Aloisia Schmid

Scanning Microscopy

Corrosion casting is an important tool for the study of microvascular structure, but unlike tissue preparation for light and electron microscopy, few controlled studies of the methods for preparation of microvascular casts for scanning electron microscopy have been reported. Most vascular casting begins with rinsing cells from the lumen of the blood vessels, but the necessity of this has not been shown. Because of a report of successful casting without rinsing and light microscopic evidence of edema with complete rinsing prior to casting, this preparation procedure was examined. Casts of lung vasculature that were thoroughly rinsed were compared to those ...


A Review Of Methodology And Quantification In Dental Microwear Analysis, K. D. Gordon Dec 1987

A Review Of Methodology And Quantification In Dental Microwear Analysis, K. D. Gordon

Scanning Microscopy

Dental microwear analysis is a method of inferring oral events (primarily food processing and aspects of masticatory biomechanics) from microscopic abrasion patterns retained on the enamel surfaces of teeth. Although some qualitative pattern differences may be easily distinguishable, most of the significant results produced thus far have derived from quantified studies of SEM images of occlusal enamel. It often goes unnoticed by readers of microwear reports who are not themselves specialists that microwear analysis is essentially a statistical method, not a visual one. In this review of current techniques and methods, several problems in current approaches are detailed. It is ...


Industrial Applications Of Auger Surface Analysis, R. E. Chase, G. S. Cole Dec 1987

Industrial Applications Of Auger Surface Analysis, R. E. Chase, G. S. Cole

Scanning Microscopy

Scanning Auger microscopy is distinguished by its unique combination of surface selectivity, high spatial resolution, ease of identifying elements and quantifying composition, and ability to distinguish between chemical states. This paper describes several applications of scanning Auger microscopy, emphasizing the range of industrial research activities:

1. Electronic Materials. Contamination in an integrated circuit processing facility was identified and procedures for its removal determined. Causes for the delamination of printed circuit board foils were identified. Superlattice films were characterized and the deposition process evaluated.

2. Tribology. Analysis of surfaces in lubricated sliding contact revealed the effects of con tact kinematics and ...


A Review Of Dental Microwear And Diet In Modern Mammals, Mark F. Teaford Dec 1987

A Review Of Dental Microwear And Diet In Modern Mammals, Mark F. Teaford

Scanning Microscopy

Recent work has shown that microscopic wear patterns on teeth may yield insights into variations in diet and tooth use in modern and prehistoric mammals. This paper presents a review of dental microwear and diet in modern mammals, plus a discussion of topics for further research. To date, incisor and molar microwear have been examined, although there are far fewer studies of the former. Facilitated by the use of high-resolution casts and scanning electron microscopy, analyses have ranged from: qualitative to quantitative, low magnification to high magnification, and experimental studies to comparative studies of museum collections. Results are encouraging and ...


Northeast Research Station Watertown, South Dakota Annual Progress Report, 1987, Agricultural Experiment Station, Plant Science Department Dec 1987

Northeast Research Station Watertown, South Dakota Annual Progress Report, 1987, Agricultural Experiment Station, Plant Science Department

Agricultural Experiment Station and Research Farm Annual Reports

This is the 1987 annual progress report for the Northeast Research Station in Watertown, South Dakota. This report is issued by the South Dakota Agricultural Experiment Station and the South Dakota State University Plant Science Department. This report includes information on the 1987 crop season, including precipitation data, grain and wheat research and disease control, corn breeding, sunflower breeding, insect control, alfalfa test, oats research, and information on the economics of alternative farming.


Oyster Spatfall In Virginia Rivers: 1987 Annual Summary, James Whitcomb Dec 1987

Oyster Spatfall In Virginia Rivers: 1987 Annual Summary, James Whitcomb

Reports

The Virginia Institute of Marine Science (VIMS) conducts weekly surveys from June through early October to obtain oyster spatfall information. Spat counts are made on oyster shells strung on wire and suspended from stakes on public and private beds. The number of spat on shells is counted each week of the spawning season to determine the potential of a particular area for receiving a strike and to predict the most likely period the strikes will occur.


Microanalytical And Micromorphological Investigations Of High Temperature Materials With And Without Protective Coatings, Volker Thien, W. Voss Dec 1987

Microanalytical And Micromorphological Investigations Of High Temperature Materials With And Without Protective Coatings, Volker Thien, W. Voss

Scanning Microscopy

The phenomenon "High Temperature Corrosion" (HTC) is described; three different types (pure oxidation, high temperature hot corrosion, low temperature hot corrosion) are defined. HTC is demonstrated taking gas turbine blades as an example. The results of laboratory HTC tests under defined conditions were compared with those of long time engine experience; the agreement is very satisfactory.

Metallurgical investigations with scanning electron microscopy and EDX-/WDX-analytical techniques gave explanations for the behaviour of protective coatings . The corrosion mechanism of a NiCrAlY-plasma spray coating is explained as consequence of Cr- and Al-oxidation. A special analytical technique - the "integral layer profile analysis" is ...


Preparation Of Biological Samples For Transmission X-Ray Microanalysis: A Review Of Alternative Procedures To The Use Of Sectioned Material, D. C. Sigee Dec 1987

Preparation Of Biological Samples For Transmission X-Ray Microanalysis: A Review Of Alternative Procedures To The Use Of Sectioned Material, D. C. Sigee

Scanning Microscopy

Although transmission X-ray microanalysis of biological material has traditionally been carried out mainly on sectioned preparations, a number of alternative procedures exist. These are considered under three major headings - whole cell preparations, analysis of cell homogenates and biological fluids, and applications of the technique to microsamples of purified biochemicals. These three aspects provide a continuous range of investigative level - from the cellular to the molecular.

The use of X-ray microanalysis with whole cell preparations is considered in reference to eukaryote (animal) cells and prokaryotes - where it has particular potential in environmental studies on bacteria. In the case of cell homogenates ...


Influence Of Phosphorus And Sulphur Segregation On Stress Relief Cracking, H. Horn, T. Pintat, V. Schlett, H. Weiss Dec 1987

Influence Of Phosphorus And Sulphur Segregation On Stress Relief Cracking, H. Horn, T. Pintat, V. Schlett, H. Weiss

Scanning Microscopy

Three commercial weldable fine grained structural steels and four experimental melts with lowered contents of trace elements were subjected to a welding simulation treatment followed by stress relaxation (SR) tests. After testing times of up to 8 hours the samples were removed from the testing rig, broken in the fracture stage of an Auger instrument, and the fracture surface was examined in situ for segregation of elements. SEM investigations of the fracture surfaces and light microscope served to characterize fracture mode and microstructure.

The microfractural appearance of the grain boundaries exposed by the impact loading in the Auger instrument and ...


Processing Of Scanning Electron Microscope Images On Basis Of Fast Fourier-Transformation, A. Yu. Sasov, A. A. Shanyavsky Dec 1987

Processing Of Scanning Electron Microscope Images On Basis Of Fast Fourier-Transformation, A. Yu. Sasov, A. A. Shanyavsky

Scanning Microscopy

The solar cell as a combined substrate and detector was used for automated SEM-image analysis. It was noted that an image processing system was created and its operational features are shown in some typical applications. The step size of the fatigue striations was found. The obtained value of the step corresponds to the formula with an accuracy of about 1 per cent. Quantum-mechanical constant of material fracture for aluminum alloys was found to be 𝛥 = 0.22. Two-dimensional periodic analysis was applied to fracture surfaces and a microchannel plate. The integral characteristics of microstructure was determined quantitatively.


Book Review- Nebraska Bird Review (December 1987) Dec 1987

Book Review- Nebraska Bird Review (December 1987)

Nebraska Bird Review

A Field Guide to Hawks of North America, William S. Clark. Illustrations by Brian K. Wheeler. 1987. Number 35 in The Peterson Field Guide Series. edited by Roger Tory Peterson. Houghton Mifflin Co., Boston. xii + 198 pp., 24 color plates. 2 black-and-white plates, 241 photographs. 6 figures. 32 maps. ISB N 0- 395-36001 - 3 (hardcover) $19.95, ISBN 0-395-44112-9 (softcover) $13.95.

The softcover is a mere 4.5 x 7.25 inches, and less than 0.75 inches thick, but the wealth of information concerning the field identification of diurnal raptors is enormous. William S. Clark, from Arlington, VA ...


Eskimo Curlew Sighted Dec 1987

Eskimo Curlew Sighted

Nebraska Bird Review

When Craig Faanes, Grand Island, went to the Mormon Island Crane Meadows 16 April 1987 to watch Sandhill Cranes at night he saw a bird that he first took for a Whimbrel. He was familiar with Whimbrels on both coasts, but the more he studied the bird the more he was convinced that the bird was an Eskimo Curlew. After he had gone to the natural history museum at UNL and studied a stuffed Eskimo Curlew be was convinced that that was what he had seen. After the date of this sighting Eskimo Curlews were reported from "the Sabine and ...


Early Fall Migration Of Sedge Wrens, Paul A. Bedell Dec 1987

Early Fall Migration Of Sedge Wrens, Paul A. Bedell

Nebraska Bird Review

Johnsgard (1980) lists the Sedge Wren (Cistothorus platensis) as an uncommon spring and fall migrant in eastern Nebraska, and a rare summer resident in eastern Nebraska, mostly east of a line from Knox to Gage counties. Half of the initial spring records occur between 1 and 12 May, with the latest 3 June. Half of the final fal1 records occur between 11 Sept. and 9 Oct., with the earliest 29 July. This paper presents observations of Sedge Wrens during 1987 in southcentral Nebraska, west of the line.

I found Sedge Wrens to be local1y common in grassy or marshy areas ...


Research Report No. 17, Stand Structure And Yield Of Slash Pine Plantations In East Texas, Update: 1987, J. David Lenhart Dec 1987

Research Report No. 17, Stand Structure And Yield Of Slash Pine Plantations In East Texas, Update: 1987, J. David Lenhart

Informal Project Reports

An updated diameter distribution yield prediction system is Presented for slash pine ( Pinus elliottii Engelm. ) plantations on non-old-fields in East Texas. The new revised system was developed using data from initial measurement ( 1982- 84) and first remeasurement ( 1985-87) of the East Texas Pine Plan tat ion Research Project permanent Plots.


Obstructing Giant Pseudopolyposis Of The Colon In Ulcerative Colitis, Roberta E. Sonnino, Farouck N. Obeid Dec 1987

Obstructing Giant Pseudopolyposis Of The Colon In Ulcerative Colitis, Roberta E. Sonnino, Farouck N. Obeid

Henry Ford Hospital Medical Journal

Pseudopolyposis of the colon is a well-recognized local complication of ulcerative colitis. Giant pseudopolyposis is uncommon, and its presentation as a complete obstruction of the colon is a rare occurrence. We report such a case, where retrograde flow of barium on double-contrast barium enema was completely obstructed at midtransverse colon. After resection by total abdominal colectomy, pathology examination ofthe specimen confirmed massive pseudopolyposis without malignancy. A brief review of the pathology and current literature is presented.


Naltrexone Does Not Affect Adrenal Steroidogenesis In Women With Hirsutism/Oligomenorrhea, Jeffrey A. Jackson, Thomas J. Wincek, Jose F. Pliego Dec 1987

Naltrexone Does Not Affect Adrenal Steroidogenesis In Women With Hirsutism/Oligomenorrhea, Jeffrey A. Jackson, Thomas J. Wincek, Jose F. Pliego

Henry Ford Hospital Medical Journal

We studied the effects of the oral opiate receptor antagonist naltrexone on basal and ACTH-stimulated adrenal steroid levels in six women with hirsutism/oligomenorrhea and preexisting elevation of serum dehydroepiandrosterone sulfate. One of the six patients met the criteria for partial 3-β-hydroxysteroid dehydrogenase deficiency. No statistical differences were detected in steroid levels or ratios before and after 14 days of 50 mg/day of naltrexone. Thus, we find no support for the hypothesis that opioid peptides acting through opiate receptors (predominantly μ subtype) modulate the abnormal adrenal androgen secretion seen in these women with hirsutism/oligomenorrhea.


Diet-Selection Ecology Of Tropically And Temperately Adapted Honey Bees, Robert G. Danka, Richard L. Hellmich, Thomas E. Rinderer, Anita M. Collins Dec 1987

Diet-Selection Ecology Of Tropically And Temperately Adapted Honey Bees, Robert G. Danka, Richard L. Hellmich, Thomas E. Rinderer, Anita M. Collins

Richard L Hellmich

Colonies of tropically adapted (Africanized) honey bees had greater numbers and higher percentages of pollen foragers than did temperately adapted (European) honey bees. European colonies had greater overall foraging activity. The number of pollen gatherers in Africanized nests was greater throughout the daily foraging cycle, and was especially high early in the morning when pollen was most abundant. Africanized colonies fielded more pollen collectors even when levels of stimuli which are known to regulate pollen foraging were altered experimentally. Collectively, the foraging patterns resulted in larger stores of pollen in Africanized honey bee nests, while European bee nests typically had ...


Factors Affecting Frost Damage To Wheat In Western Australia, S P. Loss Dec 1987

Factors Affecting Frost Damage To Wheat In Western Australia, S P. Loss

Division of Plant Research : Technical Report Series

It may at first seem strange that precious research funds are being channelled into a project concerned with frost damage in a country where high temperatures and moisture stress limit the growth of plants for a large portion of the year. But cereal crops are only grown in the temperate zones of the continent during winter and spring when they may be exposed to low diurnal temperatures. In many areas cold damage is irregular and rare,however it limits yields not only by causing actual damage but also by restricting the most effective period for flowering. For muck of the ...


Disease And Insect Resistance Screening Of The National Subterranean Clover Collection, D J. Gillespie, M J. Barbetti Dec 1987

Disease And Insect Resistance Screening Of The National Subterranean Clover Collection, D J. Gillespie, M J. Barbetti

Division of Plant Research : Technical Report Series

This project commenced in May 1981 primarily to identify sources of resistance to clover scorch (Kabatiella caulivora), root rots (Pythium, Fusarium and Rhizoctonia spp.), and bluegreen aphid (Acyrthospihon kondoi) in the National Subterranean Clover Collection. Screening for resistance to red legged earthmite (Halotydeus destructor) was initiated part way through the project. Since commencement approximately 5,250 introductions and crossbred clover shave been tested for resistance to clover scorch, 420 for resistance to rootrots, 690 for resistance to blue green aphid and 160 for resistance to redlegged earth mite (R.L.E.M.). A large number of clovers possessing resistance to ...


The 1987 Iowa Corn Yield Test Report, District 5, K.E. Ziegler Dec 1987

The 1987 Iowa Corn Yield Test Report, District 5, K.E. Ziegler

Iowa Corn Yield Tests

Results of the Iowa Com Yield Test are published to aid Iowa farmers in selecting corn hybrids. This is the sixty-eighth consecutive year for the test. The presentation of data for the hybrids tested does not imply approval or endorsement by the authors or by the agencies sponsoring or conducting the test. Entries in tables I and 2 are designated by brand name and variety.


The 1987 Iowa Corn Yield Test Report, District 4, K.E. Ziegler Dec 1987

The 1987 Iowa Corn Yield Test Report, District 4, K.E. Ziegler

Iowa Corn Yield Tests

Results of the Iowa Com Yield Test are published to aid Iowa farmers in selecting com hybrids . This is the sixty-eighth consecutive year for the test. The presentation of data for the hybrids tested does not imply approval or endorsement by the authors or by the agencies sponsoring or conducting the test. Entries in tables land 2 are designated by brand name and variety.


The 1987 Iowa Corn Yield Test Report, District 1, K.E. Ziegler Dec 1987

The 1987 Iowa Corn Yield Test Report, District 1, K.E. Ziegler

Iowa Corn Yield Tests

Results of the Iowa Com Yield Test are published to aid Iowa farmers in selecting com hybrids. This is the sixty-eighth consecutive year for the test. The presentation of data for the hybrids tested does not imply approval or endorsement by the authors or by the agencies sponsoring or conducting the test. Entries in tables I and 2 are designated by brand name and variety.


The 1987 Iowa Corn Yield Test Report, District 2, K.E. Ziegler Dec 1987

The 1987 Iowa Corn Yield Test Report, District 2, K.E. Ziegler

Iowa Corn Yield Tests

Results of the Iowa Com Yield Test are published to aid Iowa farmers in selecting com hybrids. This is the sixty-eighth consecutive year for the test. The presentation of data for the hybrids tested does not imply approval or endorsement by the authors or by the agencies sponsoring or conducting the test. Entries in tables land 2 are designated by brand name and variety.


The 1987 Iowa Corn Yield Test Report, District 7, K.E. Ziegler Dec 1987

The 1987 Iowa Corn Yield Test Report, District 7, K.E. Ziegler

Iowa Corn Yield Tests

Results of the Iowa Corn Yield Test are published to aid Iowa farmers in selecting corn hybrids . This is the sixty-eighth consecutive year for the test. The presentation of data for the hybrids tested does not imply approval or endorsement by the authors or by the agencies sponsoring or conducting the test. Entries in tables 1 and 2 are designated by brand name and variety.