Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Life Sciences

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 49981 - 50010 of 52497

Full-Text Articles in Entire DC Network

Models For Estimating Energy And Protein Utilization For Feeds, Muhammad Fadel Wardeh May 1981

Models For Estimating Energy And Protein Utilization For Feeds, Muhammad Fadel Wardeh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Data on the proximate nutrient content of feedstuffs, digestibility and energy utilization available from the International Feedstuffs Institute (Utah State University) were used to develop mathematical models for estimating energy and protein utilization of five classes of feedstuffs for various kinds of animals.

Classes of feedstuffs were subdivided into more related subclasses. Furthermore, data from all feeds were pooled together then subgrouped into more related subgroups in an attempt to gain high precision in prediction of digestible proximate nutrients and TDN from a single chemical entity by the use of simple regression models (Y = bo + b1x …


An Economic Analysis Of Farm Flock Sheep Production In Utah, Ken Beck May 1981

An Economic Analysis Of Farm Flock Sheep Production In Utah, Ken Beck

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to evaluate the economic aspects of farm flock sheep production in Utah. Using 1979 as a base year, costs and returns were calculated from data obtained from twenty- six Utah farms. Characteristics that typify the states· farm flock sheep production, at this writing, with regard to: 1) the farm flock producers and 2) the farm flock enterprise, were presented.

Various models were dev eloped and examined using Multiple Regression and Linear Programming analytical techniques. Multiple Regression was us ed to estimate the effects that different variables had on the profitability of the sheep enterprise. …


Hydraulic Conductivity And Drought Acclimation Of Cotton Root Systems, Derrick M. Oosterhuis May 1981

Hydraulic Conductivity And Drought Acclimation Of Cotton Root Systems, Derrick M. Oosterhuis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Hydraulic conductivity of single roots and whole root systems was studied for soil, sand and solution-grown cotton plants (Gossypium hirsutum L.). Conductivity varied widely depending on plant age and growing conditions. Total conductivity for soil-grown plants decreased from 357 x 10-6 µ1 s-1 bar-1 cm-1 one week after germination to 5 x 10-6 µ1 s-1 bar-1 cm-1 at boll set. There was a concomitant increase in total root length. Solution-grown plants had higher root conductivities than soil- or sand-grown plants. Root conductance was decreased by low temperatures, lack of oxygen and …


The Transport And Intracellular Distribution Of Iron In The Basidiomycete, Ustilago Sphaerogena, Charles W. Passavant May 1981

The Transport And Intracellular Distribution Of Iron In The Basidiomycete, Ustilago Sphaerogena, Charles W. Passavant

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The transport and intracellular distribution of iron in Ustilago sphaerogena via the native siderochrome ferrichrome A has been examined. Evidence is presented which suggests the involvement of deferriferrichrome in iron transport when the metal is supplied to the cell as ferrichrome A. This process requires both oxygen and ATP synthesis and may require a transmembrane electrochemical gradient. Once inside the cell, iron derived from ferrichrome A is rapidly distributed, with a major fraction found in the mitochondria, presumably as heme.

The kinetics of ferrichrome and ferrichrome A uptake have also been investigated. The Km of transport of ferrichrome was …


Seasonal Temperature Preference Of Adult Mountain Whitefish, Prosopium Williamsoni, Jean M. Ihnat May 1981

Seasonal Temperature Preference Of Adult Mountain Whitefish, Prosopium Williamsoni, Jean M. Ihnat

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Temperatures selected seasonally by adult mountain whitefish were measured in the laboratory in a horizontal gradient. Final preferendum estimates, based on acute (3-hour) preference tests conducted with fish acclimated to 5, 10, and 15 C each season, were 17.7 C (pre-spawning), 11.9 C (post-spawning), 9.9 C (winter), and 16.3 C (spring). Seasonal influence on temperature selection was evident on the basis of differences in final preferenda, covariance analysis of responses of laboratory-acclimated fish, and temperature selection by fish held at ambient river temperatures. Post-spawning and winter groups selected lower temperatures than did pre-spawning and spring groups. Pre-spawning fish selected temperatures …


Higher Plant Acclimation To Solar Ultraviolet-B Radiation, Ronald Robberecht May 1981

Higher Plant Acclimation To Solar Ultraviolet-B Radiation, Ronald Robberecht

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plant acclimation to natural and intensified solar UV-B irradiance was investigated in three species, Oenothera stricta Ledeb., Rumex obtusifolius L., and R. patientia L. The objectives of this study were to determine: (1) the relationship between plant sensitivity and epidermal UV attenuation, (2) the effect of phenotypic changes in the leaf epidermis, resulting from UV-B exposure, on plant sensitivity to UV radiation, and (3) the plasticity of these changes in the epidermis leading to plant acclimation to UVB radiation.

Epidermal UV transmittance was found to differ in magnitude and spectral distribution among the three species examined in this study. Epidermal …


Some Morphological And Chemical Responses Of Blackbrush (Coleogyne Ramosissima) To Goat Browsing: Influences On Dietary Blackbrush Selection By Goats And Cattle, Frederick D. Provenza May 1981

Some Morphological And Chemical Responses Of Blackbrush (Coleogyne Ramosissima) To Goat Browsing: Influences On Dietary Blackbrush Selection By Goats And Cattle, Frederick D. Provenza

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Domestic goats were used to modify the growth form of blackbrush, a spinescent shrub occurring in nearly monospecific stands on several million hectares of rangeland in the southwestern United States. The objective of this research was to evaluate goat browsing as a means of improving these rangelands for cattle. Winter goat browsing stimulated spring twig growth from basal and axillary buds which resulted in increased production.

Twig production by heavily browsed plants (>95 percent removal of current season's twigs) was a function of precipitation, soil depth, branch location on the plant, and period of rest after browsing. As precipitation …


Natural Pastures Of The Macquarie Region Of New South Wales: Their Origin, Composition And Management, David Leslie Michaelk May 1981

Natural Pastures Of The Macquarie Region Of New South Wales: Their Origin, Composition And Management, David Leslie Michaelk

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two experiments were conducted in the semi-arid (400 millimeter annual rainfall) Macquarie region of New South Wales, Australia, at the Trangie Agricultural Research Station (31° 59'S; 147° S7'E), to examine (a) the way botanical parameters can be used to separate grazing and climatic impacts on range vegetation, and (b) how this delineation affects application of range science tenets (site, condition and trend) to different pasture types.

Two range sites were studied: Site 1, a light soil type, was dominated by annual grasses, legumes and forbs, whereas perennial grasses (mainly Chloris acieularis and Chloris truncata) dominated the heavy soils of …


Effect Of Mild Water Stress And Enhanced Ultraviolet-B Irradiation On Leaf Growth Of Rumex Obtusifolius L. And Rumex Patientia L. (Polygonaceae)., Steve R. Holman May 1981

Effect Of Mild Water Stress And Enhanced Ultraviolet-B Irradiation On Leaf Growth Of Rumex Obtusifolius L. And Rumex Patientia L. (Polygonaceae)., Steve R. Holman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Leaves of Rumex obtusifolius L. and R. patientia L.were exposed to combinations of mild water stress and enhanced ultraviolet-B irradiation during their ontogeny. Two UV-B treatments (enhanced UV-B and control) and three water stress treatments (-0.0 MPa, -0.2 MPa and -0.4 MPa rooting medium matric potentials) were employed. The impact of the stress interaction was assessed on the basis of changes in leaf area, average adaxial epidermal cell size, and total number of adaxial epidermal cells per leaf. Although the level of UV-B irradiation applied was insufficient to significantly alter leaf growth at any given water stress, UV-B did interact …


The Energy Expenditure Of Heifers Grazing Crested Wheatgrass Rangeland In West-Central Utah, Kris M. Havstad May 1981

The Energy Expenditure Of Heifers Grazing Crested Wheatgrass Rangeland In West-Central Utah, Kris M. Havstad

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The free-roaming ruminant requires energy for the demands of vii grazing, traveling and thermoregulation that are not required by its confined counterpart. Literature estimates of these additional costs range from 10 to 170 percent above maintenance. The uncertain magnitude of this increased demand and the factors that contribute to it impede the ability of the rangeland ruminant nutritionist to establish guidelines for the energy requirements of the free-roaming herbivore. This study was designed to estimate the energy expenditure of yearling Angus heifers while grazing a declining supply of available crested wheatgrass forage (Agropyron cristatum) on rangeland in west-central …


The Rhode Island Quahogger: Candidate For The List Of Endangered Species?, James M. Korney Apr 1981

The Rhode Island Quahogger: Candidate For The List Of Endangered Species?, James M. Korney

Marine Affairs Theses and Major Papers

It is the hypothesis of this paper that today the livelihood of the independent Narragansett Bay quahogger is faced with two potentially dangerous threats; water pollution in upper Narragansett Bay and the prospect of an expanding aquaculture industry in the lower bay. Unless the state of Rhode Island properly interprets and enforces existing state legislation to protect the quahoggers interests, his very livelihood will be jeoprodized. This paper will examine the legal, political, economic, and environmental affects of water pollution in upper Narragansett Bay and an expanding aquaculture industry in the lower bay in their relation to the Rhode Island …


Municipal Sewage Treatment: Problems And Considerations, George R. Johnson Apr 1981

Municipal Sewage Treatment: Problems And Considerations, George R. Johnson

Marine Affairs Theses and Major Papers

The coastal areas are vital to the economic and physical well being of the United States. Virtually every facet of our way of life is related in some fashion to these coastal areas. Ocean borne transportation moves not only vast quantities of raw materials, but also many of the intermediate and final products that are then manufactured to their related market areas. Fisheries provide vast amounts of food and employment for many of our people. In addition, the coasts are a continuing source of enjoyment and recreation for millions of our citizens. Coastal waters provide much of the water necessary …


93rd Session Iowa Academy Of Science Awards Luncheon, April 24, 1981, Iowa Academy Of Science Apr 1981

93rd Session Iowa Academy Of Science Awards Luncheon, April 24, 1981, Iowa Academy Of Science

Iowa Academy of Science Documents

Program:

--- Introduction of Head Table - Donald M. Huffman, Central College, President, Iowa Academy of Science
--- Recognition of students participating in various state-wide activities - Gary Downs, Chair, Student Programs Committee
--- Presentation of students selected to present papers at the 1981 Iowa Academy Meeting and announcement of those selected to represent Iowa at the American Junior Academy of Science Meeting, Washington DC, January 1982 - Joe Moore, Director, Iowa Junior Academy of Science
--- Presentation of the Excellence in Science Teaching Award in Biology, Chemistry, Physics, Earth Science, Elementary Science, Junior High Science - David McCalley, University …


Abstracts Of Papers, 93rd Session, Iowa Academy Of Science, April 24-25, 1981, Iowa Academy Of Science Apr 1981

Abstracts Of Papers, 93rd Session, Iowa Academy Of Science, April 24-25, 1981, Iowa Academy Of Science

Iowa Academy of Science Documents

Presentation abstracts from the annual meeting of the Iowa Academy of Science


The Annual Meeting Of The Iowa Academy Of Science April 24-25, 1981 [Program, 93th Meeting], Iowa Academy Of Science Apr 1981

The Annual Meeting Of The Iowa Academy Of Science April 24-25, 1981 [Program, 93th Meeting], Iowa Academy Of Science

Iowa Academy of Science Documents

No abstract provided.


Field Studies Comparing The Effectiveness Of A Synthetic Female Sex Pheromone ([R,Z]-5-[1-Decenyl] Dihydro-2[3h]-Furanone) And A Floral Bait (Phenylethyl Propionate + Eugenol 7:3) In Controlling Adult Populations Of The Japanese Beetle (Popillia Japonica Newman), Sharon Kay Stahl Apr 1981

Field Studies Comparing The Effectiveness Of A Synthetic Female Sex Pheromone ([R,Z]-5-[1-Decenyl] Dihydro-2[3h]-Furanone) And A Floral Bait (Phenylethyl Propionate + Eugenol 7:3) In Controlling Adult Populations Of The Japanese Beetle (Popillia Japonica Newman), Sharon Kay Stahl

Morehead State Theses and Dissertations

A thesis presented to the faculty of the School of Sciences and Mathematics at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Sharon Kay Stahl on April 22, 1981.


Maine's Whitewater Rapids And Their Relevance To The Critical Areas Program, Janet Mcmahon Apr 1981

Maine's Whitewater Rapids And Their Relevance To The Critical Areas Program, Janet Mcmahon

Maine Collection

Maine's Whitewater Rapids and Their Relevance to the Critical Areas Program

by Janet McMahon

Planning Report No. 74, Critical Areas Program, 184 State St., Augusta, Maine,

April, 1981 (additions made in October, 1981). Reprinted July, 1983.

Contents: Introduction / Natural History of Whitewater Rapids / Methods / Criteria / Results / Conclusions / General Evaluation of Whitewater Rapids for Inclusion on the Register of Critical Areas / Bibliography / Action Plan


The Role Of Cationic Polymers In Water Removal On A Paper Machine, Paul T. Miller Apr 1981

The Role Of Cationic Polymers In Water Removal On A Paper Machine, Paul T. Miller

Paper Engineering Senior Theses

Cationic polymers have often been termed as both retention and/or drainage aids. A distinction was made between these two terms. Essentially drainage aids should be viewed as dewatering aids and retention aids should be viewed as those polymers that give superior retention. These effects may be interrelated, therefore the dominant characteristic should be used to classify these polymers. There have been many claimed benefits associated with the use of these cationic polymers in stock furnishes. The author felt that claimed dewatering benefits were mostly a matter of conjecture and contradictions existed. Therefore a pilot. paper machine study was designed to …


The Effects Of Cationic Valence On Wash Deinking Of Newsprint, Lawrence E. Mcenroe Apr 1981

The Effects Of Cationic Valence On Wash Deinking Of Newsprint, Lawrence E. Mcenroe

Paper Engineering Senior Theses

The effects of cationic valence were tested against final pulp brightness in the wash deinking process on newsprint. The electrolytes used were AlCl3,CaCl2 and NaCl. The concentrations were varied from 8.32 x 10-4 M to 100 times that amount on all three electrolytes. The effects were studied on the wash water and the cooking liquor seperately, using deionized water as a control run. It was found that there was a noticeable loss of brightness even at the lowest level of electrolyte addition in both the wash water trials and the cooking liquor trials. The effect was …


Mouthpart Morphology And Feeding Strategies Of The Commensal Amphipod, Anamixis Hanseni Stebbing, James Darwin Thomas, George W. Taylor Apr 1981

Mouthpart Morphology And Feeding Strategies Of The Commensal Amphipod, Anamixis Hanseni Stebbing, James Darwin Thomas, George W. Taylor

Marine & Environmental Sciences Faculty Articles

The lack of the information on the biology of the commensal amphipod family Anamixidae prompted investigations into mouthpart ultrastructure, feeding biology, and host specificity of Anamixis hanseni Stebbing, 1897. Earlier investigators presented conflicting reports on the structural composition of the buccal region and feeding modes in anamixids. Scanning electron microscope analysis of A. hanseni showed a complete set of mouthparts to be present, although much modified and reduced, except for the well-developed maxilliped palps. Feeding is not parasitic (piercing and sucking host tissue) as previously believed but is accomplished while A. hanseni rests inside its host. Minute food particles are …


The Diversity And Abundance Of The Benthic Macroinvertebrates In An Oligo-Mesotrophic Central Florida Lake, Jeffrey F. Spence Apr 1981

The Diversity And Abundance Of The Benthic Macroinvertebrates In An Oligo-Mesotrophic Central Florida Lake, Jeffrey F. Spence

Retrospective Theses and Dissertations

Benthic macroinvertebrates and physicochemical parameters were sampled monthly in Spring Lake, Florida from July, 1978, to June, 1979. Spring Lake is a slightly acidic, sand bottom lake located in the sandhill region of the Central Highlands. While submersed vegetation is not dense, the lake does contain an abundance of the endemic submersed plant Mayaca aubletii. The littoral zone is dominated by plants belonging to the genera Panicum, Nuphar, Hydrocotyle, Nymphaea, Satittaria, and Typha. The benthic macroinvertebrates collected consisted of 51 species; approximately 50 percent were in the family Chironomidae. The annual mean number of individuals was 947/m2. The mayfly Hexagenia …


Palynological Correlation Of The Kentucky No. 12 Coal, Gerald E. Vyhmeister Apr 1981

Palynological Correlation Of The Kentucky No. 12 Coal, Gerald E. Vyhmeister

Loma Linda University Electronic Theses, Dissertations & Projects

In attempting to analyze the depositional environment for the Kentucky No. 12 Coal three columns were sampled from a 1 km area. The columns yielded 76 miospore species belonging to 33 genera, and representing in decreasing order of abundance, arborescent lycopods, tree ferns, calamites, small ferns, gymnospermous trees, seed ferns, herbaceous lycopods, and others from unknown origin.

The pattern of spore distribution in the columns did not appear to be affected by the presence of several partings, a feature which calls into question several mechanisms proposed for the origin of partings and also creates difficulties for an autochthonous origin for …


High Performance Liquid Chromatographic Analysis Of Biogenic Amines, Thais Edwina Ahrendt Keegan Apr 1981

High Performance Liquid Chromatographic Analysis Of Biogenic Amines, Thais Edwina Ahrendt Keegan

Chemistry & Biochemistry Theses & Dissertations

The objectives of this research were to develop a sensitive method for separation and quantitation of biogenic amines and to apply that procedure by monitoring neurochemical changes resulting from stimuli to the test system.

Primary aromatic amines were derivatized with o-phthalaldehyde-mercaptoethanol prior to chromatography, Separation of the fluorescent adduct was achieved using a μBondapak/ phenyl reversed-phase column and a two-step gradient of methanol:0.08 M acetic acid, pH J.O. Fluorescence was monitored using a J40 nm excitation energy and an emission filter which transmits radiation greater than 400 nm (50% T at 418 nanometers).

Following optimization of the chromatographic conditions, studies …


Growth And Recruitment Of Two Penaeids In The Bay Of St. Louis, Mississippi During 1979, Teresa C. Heaton Apr 1981

Growth And Recruitment Of Two Penaeids In The Bay Of St. Louis, Mississippi During 1979, Teresa C. Heaton

OES Theses and Dissertations

Juvenile brown (Penaeus aztecus, Ives) and white (Penaeus setiferus, Linnaeus) shrimp were collected from two stations of a nursery area in St. Louis Bay Mississippi, during May to October, 1979. Periods of shrimp recruitment and growth were determined to discern whether the concurrent environmental variables of salinity and temperature had an influence on shrimp abundance and yield. Growth estimates were obtained from length frequency measurements of trawl samples taken over a 24-h period per month from each station. An analysis of variance of length versus the variables of sex, month, station, time of day, salinity and …


Back Matter Mar 1981

Back Matter

Henry Ford Hospital Medical Journal

No abstract provided.


Seasat Altimetry Adjustment Model Including Tidal And Other Sea Surface Effects, Georges Blaha Mar 1981

Seasat Altimetry Adjustment Model Including Tidal And Other Sea Surface Effects, Georges Blaha

Marine & Environmental Sciences Faculty Reports

This study is a part of the on-going effort aimed at improved determinations of the earth's gravity field through the adjustment of satellite altimeter data in the short-arc mode. Until recently the key role in such adjustments has been played by GEOS-3 altimeter data. However, SEASAT altimetry is envisioned as providing a more accurate means for addressing this task.

In view of the improved quality of altimeter data and of the corresponding more stringent requirements for the data reduction, several improvements in the existing altimetry model have been designed and are described herein. For example, the criteria have been established …


The Prairie Naturalist Volume 13, Number 1. March 1981 Mar 1981

The Prairie Naturalist Volume 13, Number 1. March 1981

The Prairie Naturalist

EDITOR: Dr. Paul B. Kannowski

BOOK REVIEW EDITOR: Douglas H. Johnson

TABLE OF CONTENTS

WATERFOWL USE OF A MUNICIPAL SEWAGE LAGOON ▪ G-A. D. Maxson

MASS MORTALITY OF MUSSELS FROM SLUMPING ALONG THE RED LAKE RIVER NEAR CROOKSTON, MINNESOTA ▪ A. M. Cvancara, D. J. Brown, D. K. Cudworth, and T. R. Klett

CHRISTMAS BIRD COUNTS FOR NORTH DAKOTA — 1980 ▪ R. N. Randall

BREEDING BIRDS ON WATERFOWL PRODUCTION AREAS IN NORTHEASTERN NORTH DAKOTA ▪ H. F. Duebbert

FURTHER EVIDENCE OF MARSH HAWKS FEEDING ON DUCKS ▪ R. A. Wishert, R. M. Kaminski, and D. W. Soprovich

FIRST NEST …


Comparison Of Lipid And Lipoprotein Levels In Diabetic And Non-Diabetic Juveniles Of Eastern Kentucky, Louise Mccall Isaacs Feb 1981

Comparison Of Lipid And Lipoprotein Levels In Diabetic And Non-Diabetic Juveniles Of Eastern Kentucky, Louise Mccall Isaacs

Morehead State Theses and Dissertations

A thesis presented to the faculty of the School of Science and Mathematics at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Louise McCall Isaacs on February 27, 1981.


Comparison Of Dna Synthesis Patterns In Polytene Chromosomes Between Normal And 20-Hydroxyecdysone-Treated Larvae, Eileen Robertson Feb 1981

Comparison Of Dna Synthesis Patterns In Polytene Chromosomes Between Normal And 20-Hydroxyecdysone-Treated Larvae, Eileen Robertson

Theses & Dissertations

The purpose of this study is to compare the patterns of chromosomal DNA synthesis during normal larval development with those patterns observed by Fresquez (1976) for hormonally-induced DNA synthesis. This will determine whether DNA synthesis responds in the same way in normal development as it does in the hormonally-induced state.


Aerial Spraying Trial., G A. Pearce Jan 1981

Aerial Spraying Trial., G A. Pearce

Experimental Summaries - Plant Research

Conclusions 1. The volume of application with water affected the results obtained. The visual results of Treatment 1 suggested it was not an acceptable commercial result and the plant counts support this conclusion. Treatments 2 and 3 looked very similar and were very similar and were very acceptable results. 2. The height of spraying affected the results in that where the plane had to start climbing to pass over trees, the effectiveness dropped off. 3. Spray drift could be a problem because of the risk of causing damage to trees and native vegetation. Severe damage was seen on trees at …