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Articles 19021 - 19050 of 20606

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Total Body Water And Body Composition In Phalaropes And Other Birds, Hugh I. Ellis, Joseph R. Jehl Jr Jan 1991

Total Body Water And Body Composition In Phalaropes And Other Birds, Hugh I. Ellis, Joseph R. Jehl Jr

Biology: Faculty Scholarship

Contrary to some reviews, total body water (TBW) may fall below the expected value of about 65% in birds if measured as a percentage of total body mass. However, water constitutes a relatively stable proportion (659%-70%) of body composition when measured as a percentage of lean body mass (LBM). We demonstrate this by using data from two migratory phalaropes (Phalaropus tricolor and Phalaropus lobatus), which exhibit inverse relationships between TBW and body mass and between TBW and fat content. As the phalaropes fatten before migration, lipids increase but not at the expense of water, which also increases with gains in …


Effects Of Low Energy Beta-Irradiation From Tritiated Water On The Morphology Of 3t3 Fibroblasts, Z. Somosy, Tamara Kubasova, J. Kovács, G. J. Köteles Jan 1991

Effects Of Low Energy Beta-Irradiation From Tritiated Water On The Morphology Of 3t3 Fibroblasts, Z. Somosy, Tamara Kubasova, J. Kovács, G. J. Köteles

Scanning Microscopy

Cellular alterations of cultured 3T3 cells irradiated with beta-rays from tritiated water were studied by scanning and transmission electron microscopy. We observed decreased negative surface charges, vacuolization of rough endoplasmic reticulum and Golgi-complex, degeneration of mitochondria, increase of lysosomal activity and changes in distribution and amount of microfilaments in the irradiated cells, that parallelled changes in cell shape.


Characteristics Of The Motor Responsible For The Gliding Of Native Microtubules From Squid Axoplasm, Dieter G. Weiss, Dieter Seitz-Tutter, George M. Langford Jan 1991

Characteristics Of The Motor Responsible For The Gliding Of Native Microtubules From Squid Axoplasm, Dieter G. Weiss, Dieter Seitz-Tutter, George M. Langford

Biology - All Scholarship

Nucleotide-dependent movement of native microtubules (nMTs) in squid axoplasm has biochemical and biophysical characteristics of kinesin-driven motility. However, the high vanadate and N-ethylmaleimide sensitivity and the velocity demonstrate that the properties of the native motile system differ considerably from those of purified kinesin preparations.


"Introduction" (To Alfred Russel Wallace; An Anthology Of His Shorter Writings), Charles H. Smith Jan 1991

"Introduction" (To Alfred Russel Wallace; An Anthology Of His Shorter Writings), Charles H. Smith

DLPS Faculty Publications

No abstract provided.


Culture Medium Ph Is Influenced By Basal Medium, Carbohydrate Source, Gelling Agent, Activated Charcoal, And Medium Storage Method, Henry R. Owen, Donna Wengerd, A. Raymond Miller Jan 1991

Culture Medium Ph Is Influenced By Basal Medium, Carbohydrate Source, Gelling Agent, Activated Charcoal, And Medium Storage Method, Henry R. Owen, Donna Wengerd, A. Raymond Miller

Faculty Research & Creative Activity

When four carbohydrates were tested against six commonly cited inorganic basal media, post-autoclave pH was highest for carbohydrate-free and sucrose- containing media, and progressively lower for maltose-, P lucose-, and fructose-containing media, respectively, post-autoclave pH for these media without carbohydrates was related to medium buffering capacity. Addition of gelling agents (10 of 11 tested) increased the post¬autoclave pH of MS medium containing sucrose. Neutralized and acid-washed activated charcoal also increased the post-autoclave pH of liquid and agar- solidified MS medium, and the pH changed further during 8 weeks of storage. Changes in medium pH caused by gelling agents, but not …


Catch-Effort Estimation Of White-Tailed Deer Population Size, James M. Novak, Kim T. Scribner, William D. Dupont, Michael H. Smith Jan 1991

Catch-Effort Estimation Of White-Tailed Deer Population Size, James M. Novak, Kim T. Scribner, William D. Dupont, Michael H. Smith

Faculty Research & Creative Activity

Estimation of population size is important for most research in population biology and in the management of game species. Using a stochastic, catch-effort, competing risks model (Dupont 1983), we estimated the population size of the Savannah River Site white-tailed deer (Odocotleus virginianus) herd for 1965-86. Population size varied markedly in response to changes in both hunting method and pressure. Still hunters preferentially harvested older animals compared to dog hunters. Deer were 2.37 times more susceptible to harvest from dog hunting than from still hunting. Hunter-induced mortality was estimated as 1.73 and 4.10 times as large as nonhunting mortality for still …


Frequency Distribution Of Conception Dates In A White-Tailed Deer Herd, James M. Novak, Olin E. Rhodes, Michael H. Smith, Paul E. Johns Jan 1991

Frequency Distribution Of Conception Dates In A White-Tailed Deer Herd, James M. Novak, Olin E. Rhodes, Michael H. Smith, Paul E. Johns

Faculty Research & Creative Activity

Conception dates of white-tailed deer, Odocoi/eus virginia1111s (Zinunennann, 1780) were estimated for the breeding periods of 1974 - 76 and 1984 using fall and winter- spring fetal data. Conception dates estimated from data collected in the fall were biased. This bias resulted in an earlier mean conception date than that based on information which included data from later breeding females. Mean breeding dates differed significantly between female age classes due to delayed conception in fawns which also resulted in a skewed frequency distribution of conception dates. The frequency distribution of conception dates was leptokurtotic, suggesting that the distribution is constrnincd …


High Voltage Electron Microscopy And Low Voltage Scanning Electron Microscopy Of Human Neoplastic Cell Culture, Marek Malecki Jan 1991

High Voltage Electron Microscopy And Low Voltage Scanning Electron Microscopy Of Human Neoplastic Cell Culture, Marek Malecki

Scanning Microscopy

Improved procedures were developed to correlate cell culture data with the images provided by advanced ultrastructural technologies. These procedures were compatible with the two main types of cellular behavior: adherent, spreading (melanomas, rhabdomyosarcomas) and non-adherent in suspension (leukemias).

The ultrastructure and function of spreading neoplastic cells primarily depend on surface properties of the attaching substrates. Therefore, the films used for cultured cell whole-mount ultrastructural analysis must have adherence features identical to those of standard cell culture vessels. Improved procedures were developed to produce the polystyrene films of required qualities. These films allowed processing of cells for electron microscopy including chemical …


The Species-Genus Relationship In Antillean Bat Communities, Donald A. Mcfarlane Jan 1991

The Species-Genus Relationship In Antillean Bat Communities, Donald A. Mcfarlane

WM Keck Science Faculty Papers

The ratio of the number of species to the number of genera in an island community has long been recognised as a potential proxy indicator of competitive interaction. An analysis of this relationship in the bat fauna of the Antillean archipelago demonstrates that the observed species-genus ratios are significantly depressed below null-model expectations, and that the magnitude of this depression is inversely proportional to the log of the appropriate island area. These observations are consistent with the hypothesis that interspecific competition may play an important role in structuring Antillean bat communities.


Reproductive Insularity In A Migratory Sparrow: A Field Study Of Lincoln's Sparrow Populations In Southern California, Cin Greyhaven Jan 1991

Reproductive Insularity In A Migratory Sparrow: A Field Study Of Lincoln's Sparrow Populations In Southern California, Cin Greyhaven

Theses Digitization Project

Melospiza lincolnii -- San Bernardino and San Jacinto mountain ranges -- migrational return -- Dispersal - Morphometric analysis.


Shrimp Stocking, Salmon Collapse, And Eagle Displacement, Craig N. Spencer, B. Riley Mcclelland, Jack Arthur Stanford Jan 1991

Shrimp Stocking, Salmon Collapse, And Eagle Displacement, Craig N. Spencer, B. Riley Mcclelland, Jack Arthur Stanford

Biological Sciences Faculty Publications

No abstract provided.


Preservation And Immunogold Localization Of Lipids By Freeze-Substitution And Low Temperature Embedding, Wim Voorhout, Ida Van Genderen, Gerrit Van Meer, Hans Geuze Jan 1991

Preservation And Immunogold Localization Of Lipids By Freeze-Substitution And Low Temperature Embedding, Wim Voorhout, Ida Van Genderen, Gerrit Van Meer, Hans Geuze

Scanning Microscopy

The success of postembedding immunocytochemistry depends largely on the preparation methods. The requirements for structural preservation and immunocytochemistry are in some cases contradictory. This is especially the case in the study of lipid-rich structures and the localization of lipid components. Earlier work on freeze-substitution has shown that this method is very promising for the preservation of lipids and the immunocytochemical localization of lipids at the electron microscopical level.

In this study we show that freeze-substitution in combination with low temperature embedding in Lowicryl HM20 has fulfilled this promise. Lamellar bodies in alveolar type II cells contain about 90% lipids and …


Reliability Of Intracellular Water And Ion Distributions As Measured By X-Ray Microanalysis - A Review, Thomas Von Zglinicki Jan 1991

Reliability Of Intracellular Water And Ion Distributions As Measured By X-Ray Microanalysis - A Review, Thomas Von Zglinicki

Scanning Microscopy

X-ray microanalysis can be an important tool to reveal the spatial relationships between polyelectrolytes, ions, and water as they occur within cells and tissues in vivo. To reach this goal, at least two of these three closely interrelated variables should be measured independently. Moreover, the absence of systematic errors should be proven.

The present review discusses the probability of artificial ion and water shifts between intracellular compartments due to the growth of dendritic ice crystals much larger than the cross-sectioned remnants commonly seen in frozen-dried sections. Considering the possible mechanism of ice crystal growth it is concluded that ions and …


Cryopreparation Of Tissue For Clinical Applications Of X-Ray Microanalysis, Godfried M. Roomans Jan 1991

Cryopreparation Of Tissue For Clinical Applications Of X-Ray Microanalysis, Godfried M. Roomans

Scanning Microscopy

A number of diseases is associated with changes in ion and/or water distribution at the tissue or cell level, and X-ray microanalysis can be used to investigate the relationship between the disease process and the changes in elemental distribution. For analysis of diffusible elements by X-ray microanalysis, the tissue has to be prepared by cryotechniques. To carry out studies of this kind in a clinical environment poses a number of problems. Some of these problems occur already before the tissue is frozen, others are caused by the practical and ethical limitations that are imposed on the freezing method itself when …


Aldehyde Fixation Causes Membrane Vesiculation During Platelet Exocytosis: A Freeze-Substitution Study, E. Morgenstern Jan 1991

Aldehyde Fixation Causes Membrane Vesiculation During Platelet Exocytosis: A Freeze-Substitution Study, E. Morgenstern

Scanning Microscopy

Despite a plethora of reports on the ultrastructure of secretory granule release by exocytosis, the release of coagulant activity from stimulated platelets is still being attributed to membrane vesiculation. Membrane vesiculation and the formation of myelin figures have been shown to be artifacts of glutaraldehyde GA fixation. Cells fixed by direct osmium or rapid freezing are free of such structures. Yet there is still doubt that rapid freezing interferes with vesiculation process. This study has addressed this issue by examining: (1) whether freezing and freeze-substitution affects membrane vesiculation, (2) whether paraformaldehyde-fixation also induces the phenomenon, and (3) whether the aldehyde …


Evolution Of Life History Parameters In Animals With Indeterminate Growth, Particularly Fish, Eric Charnov, David Berrigan Jan 1991

Evolution Of Life History Parameters In Animals With Indeterminate Growth, Particularly Fish, Eric Charnov, David Berrigan

Biology Faculty & Staff Publications

Optimal life history theory is used to understand the Beverton-Holt dimensionless numbers for fish life histories


Diurnal Variation In Mass, Metabolic Rate, And Respiratory Quotient In Anna's And Costa's Hummingbirds, Donald R. Powers Jan 1991

Diurnal Variation In Mass, Metabolic Rate, And Respiratory Quotient In Anna's And Costa's Hummingbirds, Donald R. Powers

Faculty Publications - Department of Biological & Molecular Science

To examine how hummingbirds that do not enter torpor at night store and utilize energy, open-circuit respirometry and a strain gauge were used to measure daily variation in 0 2 consumption (Vo2 ), C02 production, respiratory quotient (RQ), and body mass in Anna's hummingbird, Calypte anna, and Costa's hummingbird, Calypte costae. During the day, Vo2 was highly variable primarily because of dif ferences in activity among individuals. At night Vo2 varied little between individuals, but mean Vo2 was more than two times that predicted from body mass for resting, postabsorptive birds. F0.85), indicating the use of carbohydrate as a …


Osmotic Effects On Mitochondria From Two Species Of Amphibian, Bufo Marinus And Rana Catesbeiana, Jeff Duerr Jan 1991

Osmotic Effects On Mitochondria From Two Species Of Amphibian, Bufo Marinus And Rana Catesbeiana, Jeff Duerr

Faculty Publications - Department of Biological & Molecular Science

The effects ql ionic and/or osmotic change on skeletal muscle mitochondrial performance were investigated. Two substrates, pyruvate and glutamate, and variation in osmotic pressure from 205 to 360 mosm in KCl or mannitol/sucrose media had no effect on maximal respiratory rate (state 3) or coupling (respiratory control ratio) in either species. Over an equivalent range of osmolalities associated with dehydration, organismic maximal 02-consumption rates are severely diminished with increasing osmolalities. The data do not support a mitochondria/limit to organismic 02 consumption under dehydration. There were interspecies differences in state 3 respiration and coupling that were similar to differences noted in …


Decreased Sprint Speed As A Cost Of Reproduction In The Lizard Scelopours Occidentalis: Variation Among Populations, Barry Sinervo, Richard Hedges, Stephen C. Adolph Jan 1991

Decreased Sprint Speed As A Cost Of Reproduction In The Lizard Scelopours Occidentalis: Variation Among Populations, Barry Sinervo, Richard Hedges, Stephen C. Adolph

All HMC Faculty Publications and Research

Decreased mobility of gravid females is thought to be an important cost of reproduction in lizards. We measured sprint speeds of female western fence lizards (Sceloporus occidentalis Baird and Girard) before and after they had oviposited. Females from two California populations were about 20% slower when gravid, females from an Oregon population were about 30% slower, and females from a Washington population were about 45% slower, compared to their speeds after recovering from reproduction. The decrease in sprint speed persisted for several weeks after oviposition, suggesting that reproduction impairs sprint performance by affecting body condition in addition to the burdening …


Foreword, Scott F. Gilbert Jan 1991

Foreword, Scott F. Gilbert

Biology Faculty Works

No abstract provided.


Atrial Natriuretic Factor In Meriones Unguiculatus, The Mongolian Gerbil, Kyriakos Tarasidis Jan 1991

Atrial Natriuretic Factor In Meriones Unguiculatus, The Mongolian Gerbil, Kyriakos Tarasidis

Master's Theses

The basis for the great osmoregulatory ability in Meriones unguiculatus, the Mongolian gerbil, has been studied previously, but as yet no clear mechanism has been determined. The present study investigated the level of cardiac atrial natriuretic factor (ANF) under high and low sodium stress. In addition, cardiac ANF values for the Mongolian gerbil were compared with another desert mammal (Mesocricetus auratus, the Syrian golden hamster) and a non-desert mammal, (Rattus norvegicus, the white rat). ANF was found to exist in the hear atria of the Mongolian gerbil at a level of 388±66 µg ANF/g tissue. High and low sodium stress …


Factors Affecting Parental Investment Strategies In Male Waterbugs, Scott Kight Jan 1991

Factors Affecting Parental Investment Strategies In Male Waterbugs, Scott Kight

Department of Biology Faculty Scholarship and Creative Works

Male giant waterbugs (Belostoma flumineum Say) brood eggs oviposited on their dorsi by conspecific females. Preliminary observations indicate that viable egg pads are sometimes discarded before hatching. Theory predicts that such behavior should occur only if costs incurred by brooding exceed benefits of hatching the egg pad. The amount of paternal investment per pad should be similar for both large and small pad sizes, but as egg pads become smaller, investment per egg increases. Thus, smaller pads should be more likely to be discarded unhatched than larger ones. Similarly, egg pads containing inviable eggs should also be more frequently …


Drop-Box Technique For Quantitative Sampling Of Macrofauna And Aquatic Plants At Restored And Natural Wetlands, J. Douglas Oliver, Andrew J. Leslie, William M. Bartodziej Jan 1991

Drop-Box Technique For Quantitative Sampling Of Macrofauna And Aquatic Plants At Restored And Natural Wetlands, J. Douglas Oliver, Andrew J. Leslie, William M. Bartodziej

Faculty Publications and Presentations

No abstract provided.


Intracellular Ph Decreases During Entry Into Estivation In The Land Snail Oreohelix, Bernard Rees Jan 1991

Intracellular Ph Decreases During Entry Into Estivation In The Land Snail Oreohelix, Bernard Rees

Biological Sciences Faculty Publications

No abstract provided.


Genetic Analysis Of Posterior Bithorax-Complex Mutants In Drosophila Melanogaster, Chunni Duan Jan 1991

Genetic Analysis Of Posterior Bithorax-Complex Mutants In Drosophila Melanogaster, Chunni Duan

Retrospective Theses and Dissertations

No abstract provided.


Potential Impacts Of Biomass Production In The United States On Biological Diversity, James H. Cook, Jan Beyea, Kathleen H. Keeler Jan 1991

Potential Impacts Of Biomass Production In The United States On Biological Diversity, James H. Cook, Jan Beyea, Kathleen H. Keeler

School of Biological Sciences: Faculty Publications

Biomass could be a renewable source of energy and chemicals that would not add CO2 to the atmosphere. It will become economically competitive as its cost decreases relative to energy costs, and biotechnology is expected to accelerate this trend by increasing biomass productivity. Pressure to slow global warming may also make biomass more attractive. Substantial dependence on biomass would entail massive changes in land use, risking serious reductions in biodiversity through destruction of habitat for native species. Forests could be managed and harvested more intensively, and virtually all arable land unsuitable for high-value agriculture or silviculture might be used …


Littoral And Limnetic Zooplankton Communities In Lake Mead, Nevada-Arizona, Usa, Patrick J. Sollberger, Larry J. Paulson Jan 1991

Littoral And Limnetic Zooplankton Communities In Lake Mead, Nevada-Arizona, Usa, Patrick J. Sollberger, Larry J. Paulson

Publications (WR)

Zooplankton were collected from adjacent littoral and limnetic sites in Lake Mead, Nevada-Arizona, USA. Limnetic species dominated both littoral and limnetic zooplankton communities; littoral species rarely exceeded 2% of monthly total zooplankton densities. Low species richness of littoral taxa and high similarity in species composition between littoral and limnetic habitats appeared to result from uniform horizontal physical and chemical environments, due to horizontal mixing, and from the absence aquatic macrophytes. Significant differences in spatial distribution occurred in phytoplankton biomass, total zooplankton density, and fish "abundances; highest concentrations of these factors occurred nearest an inflow high in nutrients and progressively declined …


Phenology And Bionomics Of Culicoides (Diptera: Ceratopogonidae) In Glynn County, Georgia, Lisa M. Westberry Jan 1991

Phenology And Bionomics Of Culicoides (Diptera: Ceratopogonidae) In Glynn County, Georgia, Lisa M. Westberry

College of Graduate Studies: Theses & Dissertations (1964–2006)

Seasonal abundance and population densities of Culicoides species from sites in Glynn County, Georgia were surveyed using 15 New Jersey light traps during a 9-month period from April-December 1990. Environmental effects on the abundances were also analyzed. The three primary species present were: Culicoides furens (Poey), C. hollensis Mellander & Brues, and C. melleus (Coguillett). C. furens were collected year round, but predominantly during the summer. C. hollensis had a bimodal abundance (spring and fall) . C. melleus also had a bimodal abundance (late summer and fall).

Larval habitats of the primary species were identified …


Structure And Function Of Human Alphoid Dna, Darryl S. Schlegel Jan 1991

Structure And Function Of Human Alphoid Dna, Darryl S. Schlegel

Master's Theses

No abstract provided.


Nesting Ecology Of The Cooper’S Hawk In Iowa, David John Conrads Jan 1991

Nesting Ecology Of The Cooper’S Hawk In Iowa, David John Conrads

Dissertations and Theses @ UNI

The Cooper's Hawk (Accipiter cooperii) was once a common nesting raptor in Iowa. Habitat destruction, pesticides and their residues, and human persecution have recently contributed to the decline of this species throughout its range. It is listed as an endangered species in Iowa by the Iowa Department of Natural Resources. In 1988 and 1989, historic nesting areas were searched for nesting Cooper's Hawks. Areas with birds displaying breeding behavior were also searched for nests. Nests were observed to determine nesting success and productivity. Habitat characteristics were measured for 33 nests found between 1985 and 1989. Macrohabitat and microhabitat were defined …