Life Sciences Commons^™

Stress Corrosion And Stress Induced Surface Morphology Of Epitaxial Films, Michael Grinfeld

Scanning Microscopy

In addition to several new predictions, the general theory of thermodynamic stability of heterogeneous systems with rearrangement has allowed us to understand the roots of several experimental and theoretical results of the past. One of them is an outstanding paper of Asaro and Tiller on stress corrosion cracking by surface diffusion published two decades ago. We compare results of Asaro and Tiller with conclusions of thermodynamic theory of solids with rearrangement and develop some Asaro-Tiller results in the directions dictated by the needs of thin films technology and experiment. A surface diffusion model in a prestressed elastic solid is studied …

Utilization Of An Electron-Beam Tester For Determining Internal Electric Field Profiles In Micro-Structured Thin-Film Semiconductor Devices, A. Jank, M. Jung, M. Lambert, G. Lichter, H. Schmoranzer

Scanning Microscopy

An electron-beam tester was used to determine the depth profile of the internal potential distribution in an a-Si:H solar cell and hence the internal electric field profile. The a-Si:H solar cells were prepared for the measurements with the electron-beam tester by low-energy chemical plasma beam etching through a plasma-resistant mask structured by electron-beam lithography. In contrast to an earlier work, the solar cells were in situ illuminated and the electric field profiles were determined for new, degraded and in situ annealed solar cells at various cell temperatures. The measuring results demonstrate that the electron-beam testing technique in combination with a …

Comparative Scanning, Transmission And Atomic Force Microscopy Of The Microtubular Cytoskeleton In Fenestrated Liver Endothelial Cells, Filip Braet, Ronald De Zanger, Wouter Kalle, Anton Raap, Hans Tanke, Eddie Wisse

Scanning Microscopy

Endothelial fenestrae control the exchange of fluids, solutes and particles between the sinusoidal lumen and the microvillous surface of the parenchymal cells. Fenestrae have a critical dimension in the order of 150-200 nm, making it necessary to use microscopes with a resolution better than the light microscope. Comparative whole-mount preparations of isolated, purified and cultured rat liver sinusoidal endothelial cells (LEC) were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Examination of detergent-extracted LEC by SEM and TEM shows an integral cytoskeleton: sieve plates are delineated by a sieve plate-associated cytoskeleton ring and …

Characterizing The Outlines Of Degraded Fine-Particles By Fractal Dimension, Andrew Hunt, David L. Johnson

Scanning Microscopy

Fractal dimension has been used extensively as a descriptor of the rugged outlines of fine-particles. Potentially, it may be a useful parameter for characterizing the outlines of fine-particles which have been subjected to some form of chemical degradation. Here, fractal dimension values have been computed for the outlines of microscopic lead fine-particles both before and after weak hydrochloric acid dissolution experiments. Values obtained for the post-dissolution rugged profiles were greater than those of the pristine fracture grains which had a Euclidean form. The profiles of the degraded fine-particles could be characterized by a single fractal dimension value, or they exhibited …

Recognition And Phagocytosis Of Apoptotic Cells, Luciana Dini, Maria Teresa Ruzittu, Laura Falasca

Scanning Microscopy

Physiological elimination of unwanted cells within the organism occurs via cell death by apoptosis and phagocytosis of these cells represents a key event in the apoptotic process. Macrophages, which are the dedicated phagocytes, and other occasionally phagocytic cells ingest the apoptotic cells while they are still intact, thus preventing the leakage of potentially harmful materials from the dying cells. Although evidence has been presented that the elimination of apoptotic bodies from the tissue operates by means of specific recognition systems, the molecular mechanisms by which an apoptotic cell is recognized are poorly understood. Recent data indicate that phagocyte recognition of …

Scanning Electron Microscopic Study Of The Postnatal Development Of The Rabbit Cochlea, With An Emphasis On Innervation, Hirofumi Morita, Tomoyuki Hoshino, Kunihiro Mizuta, Satoshi Iwasaki

Scanning Microscopy

The development of nerve fiber arrangements of the organ of Corti was studied in rabbits 1, 3, 5, 7 and 12-days-old using thick sections from celloidin-embedded cochleas which were examined under a scanning electron microscope. The arrangements of nerve fibers varied with developmental age. The tunnel spiral bundle was thick and loosely collected in the immature cochlea. The outer spiral fibers were recognized even in the narrow space of Nuel in the one-day-old cochlea. As Nuel's space is extending, the fibers course along the medial side of Deiters' cells. The arrangement of the outer spiral fibers was irregular and sparse …

Nutritional Value Of Grazed Forages And How It Fits The Cow’S Requirement, Don C. Adams, Richard T. Clark, Terry J. Klopfenstein, Jerry D. Volesky

Range Beef Cow Symposium

The concept of matching nutrients available in grazed forages with nutrient requirements of the cow has been reviewed and recommended as a means to most efficiently utilize grazed forages (Valentine 1990, Vavra and Raleigh 1976). We further develop the principles and concepts necessary to improve the match between forage quality and the cow's nutrient needs and discuss potential impacts on management and production cost.

"Near-Organic" And "Mainstream" Crop-Livestock Production: South Dakota Case Study, Donald Taylor

Economics Research Reports

In this report, results are presented of a case study on alternative strategies for producing crops and beef cattle in South Dakota. The alternative production strategies are termed "nearorganic" and "mainstream." "Near-organic" producers were defined as farmers/ranchers1 expected to substantially meet standards of private "organic" certification authorities in raising crops and livestock, whereas "mainstream" producers were defined as those who generally follow practices recommended by the S.D. Cooperative Extension Service. Four matching pairs of near-organic and mainstream case study farmers from the following locations were selected for study: Morristown in the Northwest Region, Norris in the South Central Region, Roscoe-Eureka …

The Structure Of The G Protein Heterotrimer GIα1Β1Γ2, Mark A. Wall, David E. Coleman, Ethan Lee, Jorge A. Iñiguez-Lluhi, Bruce A. Posner, Alfred G. Gilman, Stephen R. Sprang

Biological Sciences Faculty Publications

The crystallographic structure of the G protein heterotrimer G_iα1(GDP)β₁γ₂ (at 2.3 A) reveals two nonoverlapping regions of contact between α and β, an extended interface between β and nearly all of γ, and limited interaction of α with γ. The major α/β interface covers switch II of α, and GTP-induced rearrangement of switch II causes subunit dissociation during signaling. Alterations in GDP binding in the heterotrimer (compared with α-GDP) explain stabilization of the inactive conformation of α by βγ. Repeated WD motifs in β form a circularized sevenfold β propeller. The conserved cores of these …

Cascading Disturbances In Florida Bay, Usa: Cyanobacteria Blooms, Sponge Mortality, And Implications For Juvenile Spiny Lobsters Panulirus Argus, Mark J. Butler Iv, John H. Hunt, William F. Herrnkind, Michael J. Childress, Rodney Bertelsen, William Sharp, Thomas Matthews, Jennifer M. Field, Harold G. Marshall

Biological Sciences Faculty Publications

Florida Bay, the shallow lagoon separating mainland Florida and the Florida Keys, USA, is experiencing an unprecedented series of ecological disturbances. In 1991, following reports of other ecosystem perturbations, we observed widespread and persistent blooms of cyanobacteria that coincided with the decimation of sponge communities over hundreds of square kilometers. Juvenile Caribbean spiny lobsters Panulirus argus, among other animals, rely on sponges for shelter; the impact of sponge loss on the abundance of lobsters and their use of shelter, in particular, has been dramatic. The loss of sponges on 27 experimental sites in hard bottom habitat in central Florida Bay …

Meeting Minutes, December 12th, 1995, National Smokejumper Association Executive Committee

National Smokejumper Association Meeting Minutes

Agenda: The Minutes of the Oct. 10 and Nov. 14; Treasurer's report; membership report; Committee reports:; NSA cleanup day in the Adopt a Highway Program; the future of the NSA; researching the availability of land/ facilities; New Business:; 1. Earl Cooley's offer of office space free of charge, to the NSA; 2. electric typewriter; 3. computer-on-line operations, and its potential usefullness to the NSA; 4. NSA nomination form for review by NSA Executive Committe; meeting adjourned; next meeting is scheduled;

Volume Determination Of Human Metaphase Chromosomes By Scanning Force Microscopy, Wolfgang Fritzsche, Eric Henderson

Scanning Microscopy

The scanning force microscope (SFM) yields the topography of the investigated surface. A procedure was developed which starts from this three-dimensional information to estimate the volume of a biological specimen. The volume of spread human metaphase chromosomes was determined in air and rehydrated in aqueous buffer. A difference of the determined volume of a air-dried metaphase chromosome set was found compared to values from electron microscopic investigations, and could be correlated with differences in the hydration state of the chromosomes. SFM-based relative volumes of air-dried chromosomes resembles literature data regarding volume range and distribution. Possible application of SFM-based relative volume …

The Phase Effect In Electronic Stopping: A Survey Of The Contributing Physical Processes, P. Bauer, E. Steinbauer, F. Kastner

Scanning Microscopy

The phase effect in electronic stopping deals with the question whether the energy loss of an ion due to the interaction with electrons depends on the state of aggregation of the target. It is commonly accepted that charge changing collisions of the projectile and changes in the electronic states of the target contribute to the phase effect In addition, the energy loss measurements might possibly be influenced by different impact parameter selection in the two experiments (solid and gas phase). Quantitative results of our calculations show that generally the impact parameter selection inherently present in a transmission experiment is quenched …

Evaluation Of The Surface Changes In Enamel And Dentin Due To Possibility Of Thermal Overheating Induced By Erbium:Yag Laser Radiation, Tat̂Jana Dostálová, Helena Jelíková, Otakar Krejsa, Karel Hamal

Scanning Microscopy

This study investigates the thermal danger of Erbium (Er):YAG laser ablation. Classical preparation techniques have many disadvantages caused by unfavorable changes of temperature, pressure, and by mechanical vibrations. The effect of mechanical vibrations and pressure is eliminated by use of laser ablation technique. The purpose of this study was to analyze the side effects resulting from thermal changes of enamel and dentin in extracted human teeth subjected to pulsed Er:YAG laser radiation using both wet and dry ablation methods.

The micrographs of the sections were checked and measured afterwards. The effect of the investigated laser irradiation on the origin of …

Channel Catfish, Ictalurus Punctatus, T-Lymphocyte Mitogenic Responses To Outer Membrane Proteins And Lps Of The Gram Negative Rod Bacterium, Edwardsiella Ictaluri, Barry Revis Hamilton

Morehead State Theses and Dissertations

A thesis presented to the faculty of the Department of Biological and Environmental Sciences at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Barry Revis Hamilton on December 8, 1995.

Keeping Employees "Positive And Pulling", John Flocchini

Range Beef Cow Symposium

Content:
Personal Introduction
Ranch Description
Ranch History
People
Planning Process
Benefits

Spatial Dependence Of Electron-Hole Pair Creation In Ion-Solid And Electron-Solid Interactions, F. J. García De Abajo

Scanning Microscopy

The problem of electron excitation induced by interaction of charged particles with solids is investigated on theoretical grounds. The excitation probability is calculated both in homogeneous media and at surfaces. The surface wake potential, needed in the latter, is reviewed. The cases of transmission and aloof geometries are considered separately. Surface plasmons are shown to play a crucial role in the latter. An application to coincidence scanning transmission electron microscopy (STEM) experiments is also discussed. Finally, a spatial representation of the excitation probability is presented.

Our Product, Beef – What Are Consumers Saying?, Mary M. Adolf

Range Beef Cow Symposium

The beef industry has long recognized the importance of quality and consistency in meeting the demands of customers in the marketplace. The critical nature of these product characteristics was clearly stated in the "War on Fat" report issued by the beef industry’s Value Based Marketing Task Force in 1990. That report expressed the industry’s need to define the most appropriate product mix that would achieve the highest level of consumer satisfaction and thus maximize beef demand.

The need for quality and consistency has resulted in several long range research efforts designed to develop technologies that could be used to produce …

Government Decisions And Policy: Impact On The Cattle Industry, Roy Frederick

Range Beef Cow Symposium

Unlike much of the rest of agriculture, almost all public policy that impacts the beef cow industry comes through the back door. You have never asked for price supports, income supplements or production limits like you neighbors who produce wheat, corn, sugar beets or milk. What you have asked for is a chance to compete fairly in the market place.

Some government policies help move toward the objective of good, fair markets for your product. Others don't. It's often a mixed bag, a situation I see being repeated as policymaking winds down for 1995 and we prepare for a new …

Cattle Markets And Captive Supplies – Opportunities To Improve True Value Of Cattle, Logan B. Mcclelland

Range Beef Cow Symposium

Concentration in the packing industry has resulted in 5 major packers processing over 75 percent of the cattle on feed. During the last cattle cycle, total cattle numbers declined at the same time packers were increasing chain speeds and increasing individual plant volumes. From 1987 through 1992 the cow herd did not expand, therefore, supplies of fed cattle were consumed easily by existing packing facilities. All packers participated in the cash market to some extent, but in order to guarantee sufficient supplies of fed cattle in short supply situations, packers fed their own cattle, actively contracted cattle, and created marketing …

The Use Of Composite Bulls – Long Term Benefits And Challenges, James A. Gosey

Range Beef Cow Symposium

Composite bulls won't perform magic or offset poor management but they offer a tool to help solve production/management problems and optimize production for a wide range of environments.

The impact of crossbreeding through heterosis (hybrid vigor) and utilization of breed differences (complementarity) for major traits like reproduction, calf survival, maternal ability, growth, longevity and other fitness traits is powerful. The cumulative effect of crossbreeding can increase calf weight weaned per cow exposed by 20 percent.

Conventional crossbreeding programs fall short in "management ease" because: 1) Rotations tie up several breeding pastures; thus, complicating grazing management, 2) Identification by sire breed …

New Or Emerging Infectious Diseases In Cattle, Dale M. Grotelueschen

Range Beef Cow Symposium

Disease is defined as a definite process having a characteristic progression of symptoms that may affect the whole body or any of its parts. Its cause, specific effects, and outcome may or may not be known. Infectious, metabolic, toxic, deficient, genetic and traumatic causes are examples of categories fitting the definition. Infectious processes frequently receive attention due in part to their ability to spread to other animals through various means.

Infectious processes are given "new or emerging" status for various reasons. New or relatively rare entities may become prevalent. Changes in existing infectious disease characteristics have resulted in new clinical …

Management Factors To Decrease Health Problems In Weaned Calves, M. L. Galyean, G. C. Duff, K. J. Malcom-Callis

Range Beef Cow Symposium

Economic losses caused by morbidity and mortality from bovine respiratory disease (BRD) in newly weaned/received cattle are one of the most significant problems facing the beef cattle industry. In small feedlots (100 to 1,000 animals marketed annually) throughout the United States (USDA-APHIS, 1994), death losses ranged from 1.5 to 2.7 per 100 animals marketed, with greater losses in western than in central regions of the US. Two-thirds to three-quarters of these deaths were attributed to respiratory disease (USDA-APHIS, 1994).

Two factors contribute to the high incidence of BRD in newly received, lightweight (e.g., < 400 to 500 lb) cattle. First, stresses associated with weaning and transportation negatively impact the immune system (Blecha et al., 1984) at a time when the animal is often exposed to a variety of infectious agents as a result of marketing procedures. Second, feed intake by stressed calves is typically low (Cole, 1995), averaging approximately 1.5% of BW during the first 2 wk after arrival of lightweight feeder cattle (Galyean and Hubbert, 1995). This low feed, and thereby nutrient, intake may further impair immune function (Cole, 1995). Older (e.g., yearling) cattle typically have greater intake than lightweight cattle subjected to shipping stress, although outbreaks of BRD can still be a problem in older cattle. Practices that have been used to offset these negative factors that impact the health of newly received cattle include preconditioning (Cole, 1993), on-ranch vaccination programs (Parker et al., 1993), nutritional management, and prophylactic medication. This review will emphasize nutritional and prophylactic medication approaches and their effects on performance and health of newly weaned/received beef cattle.

Reducing Calving Difficulty By Heifer And Sire Selection And Management, Gene H. Deutscher

Range Beef Cow Symposium

Calf deaths caused by dystocia (calving difficulty) result in a $600 million annual loss to U.S. beef producers (Bellows and Short, 1994). Therefore, methods to reduce dystocia must be investigated, understood, and utilized to decrease the incidence and degree of calving difficulty. A review of early research was presented at the 1989 Range Beef Cow Symposium at Rapid City (Deutscher, 1989) indicating the major cause of dystocia in first calf heifers was a disproportion between the size of calf at birth (birth weight) and the cow's birth canal (pelvic area). A pelvic area/ birth weight ratio developed in Nebraska was …

Developing Specified And Predictable Replacement Heifers, Richard (Dick) Kjerstad

Range Beef Cow Symposium

Thank you for the invitation to participate in the Range Beef Cow Symposium XIV. I have attended some of the Symposia over the years and have found them all to be very informative and educational. I congratulate the staff of the four Universities for the contribution they give to the Beef Industry.

My family has a grain and livestock operation in western South Dakota. My wife and I have four sons, who are all involved in our operation.

Developing a cow herd that will produce specific, predictable and on-time off-spring, has always been a challenge for most ranchers.

Buying feeder …

Strategic Alliances: Advantages And Challenges...Or What Does It Take To Turn A Marketing Concept Into A Business Practice?, Richard H. Lacey

Range Beef Cow Symposium

The beef industry has just lost $300 per calf weaned. Industry analysts have rumored that 40% of the beef producers are currently broke and but just don’t know it yet. Bankers tell their clients that they only have two ways to keep out of debt--cut costs, and/or make more money. Simply keeping from spending--doesn’t contribute much to refilling the coffers and satisfying cash flow--therefore cowmen are left with few alternatives. Since we can’t get more for them-- we have to figure a way to get more out of them.

The first strategic alliance study challenged traditions of "blending", "averaging", and …

What Does A Commercial Producer Expect In A Strategic Alliance?, Burke Teichert

Range Beef Cow Symposium

The discussion of strategic alliances in this setting at this time in the cattle numbers and price cycle is extremely appropriate. I am honored to have been selected to speak for commercial producers regarding what we expect of strategic alliances.

While some may have a fairly concise, narrowly defined idea of what a strategic alliance is, I would prefer a less structured view. A strategic alliance could be any long-term win/win relationship between two or more independent businesses. When this happens the businesses become inter-dependent. This makes the quality and structure of the alliance very important to all parties.

A …

What Does The Cattle Buyer Look For In Feeder Cattle?, Robbi H. Pritchard

Range Beef Cow Symposium

This subject is steeped with opinion, prejudice and fact in a recipe similar to politics. Some issues are understood, definable and reflected in market prices. We all are aware of body weight, fill, frame, and flesh influences on price and value. Unfortunately, these four factors are inadequate for identifying as much of the profit potential differences between feeder cattle as we would like. As the industry pushes to find sources of profitable cattle, a much broader range of issues is being addressed. The motives and rationales behind these promotions deserve serious scrutiny. We need to distinguish between opinion, prejudice and …

Improving Cattle Health Through Trace Mineral Supplementation, Jerry W. Spears

Range Beef Cow Symposium

A number of trace minerals are required by beef cattle. Feeds consumed by cattle may supply most trace minerals in adequate amounts. However, some minerals may be severely or at least marginally deficient in beef cattle diets. Even marginal mineral deficiencies can reduce growth, reproduction and/or health of cattle showing few if any clinical signs of deficiency. Other trace minerals such as iron and molybdenum may be naturally present in feeds in levels high enough to reduce animal productivity.

Certain trace minerals affect immunity and may affect disease susceptibility in cattle. Selenium, copper, zinc, cobalt and iron have been shown …

Understanding Basic Mineral And Vitamin Nutrition, Larry Corah

Range Beef Cow Symposium

In a typical cow-calf operation in the Great Plains, the nutritional focus is on supplying protein and energy to the cows. That focus is appropriate since these two nutrients comprise the major portion of the annual feed cost of maintaining the cow herd. Recent concerns regarding trace mineral deficiencies has resulted in more producers now asking questions about the mineral and vitamin portion of the cow herd nutrition program.

The common sense approach to supplying minerals and vitamins to beef cows should be very similar to the one used in supplying energy and protein to the cows. In other words, …