Life Sciences Commons^™

Candidate Reproductive Genes Do Not Explain Responses In Lines Selected For Ovulation Rate And Litter Size, Regina Linville, Daniel Pomp, Rodger K. Johnson

Nebraska Swine Reports

Molecular technologies have developed rapidly and provide methods to select directly for genes controlling economic traits. The swine genetic linkage map is the most highly developed of all livestock species. Positions on the chromosomes of several genes are known. Some of these genes have been shown to have direct effects on economic traits. Selection lines that differ from the control line by as much as 50% in ovulation rate and litter size exist at Nebraska. This experiment evaluated whether six specific genes that produce important proteins in reproductive processes explained responses in ovulation rate and litter size in two of …

Developing Sustainable Management Policy For The National Elk Refuge, Wyoming, Tim W. Clark, Denise Casey, Anders Halverson

Yale School of the Environment Bulletin Series

No abstract provided.

Dairy Digest 2000, South Dakota State University Dairy Club

Dairy Digest

No abstract provided.

Effect Of Calving Time And Weaning Time On Cow And Calf Performance - A Preliminary Report, R. J. Pruitt, B. Epperson, B. Johnson, D. Zalesky, R. Haigh, D. Young

South Dakota Beef Report, 2000

Cows grazing native range year round were allotted to 3 management systems: 1.) A calving season starting in mid March with calves weaned in late October; 2) A calving season starting in mid March with calves weaned in mid September; and 3) A calving season starting early May with calves weaned in late October. After 2 years of the study, pregnancy rate and calving interval were not affected by management system. Average weaning weight was the highest for the March calving/October weaned group in both years. In the first year of the study, severe winter weather caused a lower calf …

Protein-Coding Genes As Molecular Markers For Ecologically Distinct Populations: The Case Of Two Bacillus Species, T. Palys, E. Berger, I. Mitrica, L. Nakamura, Frederick Cohan

Frederick M. Cohan

No abstract provided.

Terminology Work: Tools And Processes That Make A Difference, Uwe Muegge

Uwe Muegge

Technical texts, i.e., technical literature proper (data sheets, user documentation, scientific publications, etc.), as well as the whole range of medical and legal texts, have one feature in common: Their authors make generous use of: a) words not in common usage, e.g., dongle (a computer hardware device that prevents unauthorized use of protected software); and/or b) words that are in common usage but have a slightly, or even totally, different meaning in the special language, e.g., bug (in the general sense, this means a small insect, but in the computer software field, this is a small defect in the code …

Water Fog For Repelling Birds, Larry Clark, Thomas Nachtman, John Hull

Larry Clark

No abstract provided.

Container Substrate Temperatures Affect Mineralization Of Composts, Helen T. Kraus, Robert Mikkelsen, Stuart L. Warren

Robert Mikkelsen

Traditional N mineralization studies have been conducted by soil scientists using soils and temperatures found in field production. As temperature, in part, governs the rate of mineralization, and container substrates reach much higher temperatures than do soils, the effect of these elevated temperatures on mineralization must be considered to begin to understand N mineralization in container substrates during production. The N mineralization patterns of three composts [turkey (Meleagris gallopavo) litter, yard waste, and municipal waste] were determined under three temperature regimes (45, 25, and 45/25 °C). More organic N was mineralized from composted turkey litter (CTL) than from municipal or …

Beneficial Use Of Swine By-Products: Opportunities For The Future, Robert Mikkelsen

Robert Mikkelsen

No abstract provided.

The Ethics Of Caring And Medical Education, William T. Branch Jr. Md, Macp

William T.Branch Jr.MD

The ethics of caring, though the subject of much recent discussion by philosophers, has hardly been applied to medical ethics and medical education. Based on receptivity (that is, empathy and compassion) toward and taking responsibility for other persons, the ethics of caring has particular relevance to medicine. Caring guides the physician always to remain the patient's advocate and to maintain the therapeutic relationship when dealing with and resolving ethical dilemmas. This article discusses the philosophy behind the ethics of caring and then explores three issues that arise within its context: receptivity, taking responsibility, and creating an educational environment that fosters …

Supporting The Moral Development Of Medical Students, William T. Branch Jr. Md, Macp

William T.Branch Jr.MD

Philosophers who studied moral development have found that individuals normally progress rapidly in early adulthood from a conventional stage in which they base behavior on the norms and values of those around them to a more principled stage where they identify and attempt to live by personal moral values. Available data suggest that many medical students, who should be in this transition, show little change in their moral development. Possibly, this relates to perceived pressures to conform to the informal culture of the medical wards. Many students experience considerable internal dissidence as they struggle to accommodate personal values related to …

Toward An Ecosystem Approach To Remediation In The Great Basin, Ted K. Raab

Ted K. Raab

We consider the web of interactions among geologic materials, soils, plants, and animals to ask, "If mining or other extractive energy technologies occur in desert regions, what do we need to know to return the land to productivity?" The Great Basin represents a formidable challenge in this regard, as winters in these cold deserts and seasonal lack of moisture during parts of the year severely constrain the growing season for vegetation. Due to the nature of current or proposed mining activities in this region, we have chosen to concentrate on two potential pollutants: the trace element selenium (Se) and nitrate …

Size Selectivity Of Crappie Angling, Leandro E. Miranda, Brian S. Dorr

Brian S Dorr

Abstract.—Over 6,000 black crappies Pomoxis nigromaculatus and white crappies P. annularis were tagged in five lakes and reservoirs to quantify size selectivity of angling. Total length of fish tagged ranged from 20.0 to 39.8 cm; fish caught by anglers ranged from 20.0 to 38.8 cm. Return rates were low at lengths near 20 cm, increased gradually to a peak between 26 and 32 cm, and decreased for longer fish. This pattern was consistent among the five lakes and reservoirs and did not differ between species. Observed size-selective exploitation resulted in the lopsided removal of intermediate age-classes, thereby simulating a reversed …

Endocrine Responses To Chronic Androstenedione Intake In 30- To 56-Year-Old Men, Gregory A. Brown, Matthew D. Vukovich, Emily R. Martini, Marian L. Kohut, Warren D. Franke, David A. Jackson, Douglas S. King

Warren D Franke

In young men, chronic ingestion of 100 mg androstenedione (ASD), three times per day, does not increase serum total testosterone but does increase serum estrogen and ASD concentrations. We investigated the effects of ASD ingestion in healthy 30- to 56-yr-old men. In a double-blind, randomly assigned manner, subjects consumed 100 mg ASD three times daily (n 5 28), or placebo (n 5 27) for 28 days. Serum ASD , dihydrotestosterone (DHT), free and total testosterone, estradiol, prostate-specific antigen (PSA), and lipid concentrations were measured at week 0 and each week throughout the supplementation period. Serum total testosterone and PSA concentrations …

High-Pressure Effects On Lysosome Integrity And Lysosomal Enzyme Activity In Bovine Muscle, Stéphanie Jung, Marie De Lamballerie-Anton, Richard G. Taylor, Mohamed Ghoul

Stéphanie Jung

This study was conducted to determine whether the application of high hydrostatic pressure could modify the enzymatic activity and membrane integrity of lysosomes in muscle. Several combinations of pressure (0-600 MPa) and time (0-300 s) were applied to two types of samples: purified enzymes (cathepsin D and acid phosphatase) in buffer solution and intact muscle (biceps femoris). The enzymes studied showed varying degrees of susceptibility depending on the level of pressure, holding time, and environment. Acid phosphatase activity was minimally affected by pressure in buffer solution, whereas cathepsin D was modulated significantly by the pressure and time applied. The activities …

Biodiversity And Ecosystem Functioning: Importance Of Species Evenness In An Old Field, Brian J. Wilsey, Catherine Potvin

Brian J. Wilsey

Changes in land use, habitat fragmentation, nutrient enrichment, and environmental stress often lead to reduced plant diversity in ecosystems. However, it remains controversial whether these reductions in diversity will affect energy flow and nutrient cycling. Diversity has two components: species richness, or the number of plant species in a given area, and species evenness, or how well distributed abundance or biomass is among species within a community. We experimentally varied species evenness and the identity of the dominant plant species in an old field of Quebec to test whether plant productivity would increase with increasing levels of evenness, and whether …

Effects Of Resource Availability On Carbon Allocation And Developmental Instability In Cloned Birch Seedlings, Brian J. Wilsey, Janne H. Lappalainen, Jocelyn Martel, Kyösti Lempa, Vladimir Ossipov

Brian J. Wilsey

Abundant nitrogen improves seedling growth and establishment. Vigorous growth brings about changes in rates and patterns of plant development and changes in the relationship between primary and secondary metabolism, which may make seedlings more susceptible to herbivores and pathogens than are slow-growing seedlings. We studied how nitrogen fertilization and manual defoliation of source leaves affect growth, carbon allocation, and developmental instability in cloned seedlings of white birch (Betula pubescens Ehrh.). Biomass was higher, whereas concentrations of most classes of phenolic compounds were lower in the nitrogen-rich environment. Interestingly, fertilization did not change the concentrations of cell wall–bound proanthocyanidins, which represent …

A Computationally Based Identification Algorithm For Estrogen Receptor Ligands: Part 2. Evaluation Of A Herα Binding Affinity Model, Steven P. Bradbury, O. G. Mekenyan, V. Kamenska, P. K. Schmieder, G. T. Ankley

Steven P. Bradbury

The objective of this study was to evaluate the capability of an expert system described in the previous paper (S. Bradbury et al., Toxicol. Sci. 58, 253–269) to identify the potential for chemicals to act as ligands of mammalian estrogen receptors (ERs). The basis of the expert system was a structure activity relationship (SAR) model, based on relative binding affinity (RBA) values for steroidal and nonsteroidal chemicals derived from human ERa (hERa) competitive binding assays. The expert system enables categorization of chemicals into (RBA ranges of < 0.1, 0.1 to 1, 1 to 10, 10 to 100, and >150% relative to 17b-estradiol. In the current analysis, the algorithm was evaluated with respect …

A Computationally Based Identification Algorithm For Estrogen Receptor Ligands: Part 1. Predicting Herα Binding Affinity, Steven P. Bradbury, V. Kamenska, P. Schmieder, G. Ankley, O. Mekenyan

Steven P. Bradbury

The common reactivity pattern (COREPA) approach is a 3-dimensional, quantitative structure activity relationship (3-D QSAR) technique that permits identification and quantification of specific global and local stereoelectronic characteristics associated with a chemical’s biological activity. It goes beyond conventional 3-D QSAR approaches by incorporating dynamic chemical conformational flexibility in ligand-receptor interactions. The approach provides flexibility in screening chemical data sets in that it helps establish criteria for identifying false positives and false negatives, and is not dependent upon a predetermined and specified toxicophore or an alignment of conformers to a lead compound. The algorithm was recently used to screen chemical data …

Organic Carbon Supply And Metabolism In A Shallow Groundwater Ecosystem, Michelle A. Baker

Michelle A. Baker

In groundwater ecosystems, in situ primary production is low, and metabolism depends on organic matter inputs from other regions of the catchment. Heterotrophic metabolism and biogeochemistry in the floodplain groundwater of a headwater catchment (Rio Calaveras, New Mexico, USA) were examined to address the following questions: (1) How do groundwater metabolism and biogeochemistry vary spatially and temporally? (2) What factors influence groundwater metabolism? (3) What is the energy source for groundwater metabolism?

Vocal Tract Function In Birdsong Production: Experimental Manipulation Of Beak Movements, Jeffrey Podos, W. J. Hoese, N. C. Boetticher, S. Nowicki

Jeffrey Podos

Kinematic analyses have demonstrated that the extent to which a songbird's beak is open when singing correlates with the acoustic frequencies of the sounds produced, suggesting that beak movements function to modulate the acoustic properties of the vocal tract during song production. If motions of the beak are necessary for normal song production, then disrupting the ability of a bird to perform these movements should alter the acoustic properties of its song. We tested this prediction by comparing songs produced normally by white-throated sparrows and swamp sparrows with songs produced when the beak was temporarily immobilized. We also observed how …

F-Actin Is Concentrated In Nonrelease Domains At Frog Neuromuscular Junctions, Elizabeth A. Connor, A. Duneavsky

Elizabeth A. Connor

To gain insight into the role of F-actin in the organization of synaptic vesicles at release sites, we examined the synaptic distribution of F-actin by using a unique synaptic preparation of frog target-deprived nerve terminals. In this preparation, imaging of the synaptic site was unobstructed by the muscle fiber cytoskeleton, allowing for the examination of hundreds of synaptic sites in their entirety in whole mounts. At target-deprived synaptic sites F-actin was distributed in a ladder-like pattern and was colocalized with β-fodrin. Surprisingly, F-actin stain, which we localized to the nerve terminal itself, did not overlap a synaptic vesicle marker, suggesting …

Performance Of Trees In The Massachusetts Planting Of The 1994 Nc-140 Peach Rootstock Trial Over Seven Growing Seasons, Wesley Autio, James Krupa, Jon Clement

Wesley Autio

No abstract provided.

Performance Of Trees In The Massachusetts Planting Of The 1994 Nc‐140 Apple Rootstock Trial Over Seven Growing Seasons, Wesley Autio, James Krupa, Jon Clement

Wesley Autio

No abstract provided.

Stunted Plant 1 Mediates Effects Of Cytokinin, But Not Of Auxin, On Cell Division And Expansion In The Root Of Arabidopsis Thaliana, Tobias Baskin, G.T.S. Beemster

Tobias Baskin

Plants control organ growth rate by adjusting the rate and duration of cell division and expansion. Surprisingly, there have been few studies where both parameters have been measured in the same material, and thus we have little understanding of how division and expansion are regulated interdependently. We have investigated this regulation in the root meristem of the stunted plant 1(stp1) mutation of Arabidopsis, the roots of which elongate more slowly than those of the wild type and fail to accelerate. We used a kinematic method to quantify the spatial distribution of the rate and extent of cell division and expansion, …

School Foodservice Director’S Perceived Compliance With The Dietary Guidelines For Americans, Melanie Burns

Melanie Burns

No abstract provided.

Feeding-Induced Changes In Plant Quality Mediate Interspecific Competition Between Sap-Feeding Herbivores, Merrill A. Peterson

Biology Faculty and Staff Publications

Feeding-induced plant resistance is a well-documented phenomenon for leaf-chewing insects. Furthermore, feeding-induced resistance provides the mechanistic basis for many cases of delayed interspecific competition, whereby previous feeding by one species diminishes the performance of other herbivores which attack the same plant later in the season. This phenomenon, however, has been very poorly investigated for sap-feeding insects. The results we present here for salt marsh-inhabiting planthoppers (Prokelisia dolus and P. marginata) provide one of the few known examples of delayed, plant-mediated interspecific competition between two sap-feeding insects.

Three lines of experimental evidence from the laboratory, field cages, and open …

Stranger In A Strange Land: Biotechnology And The Federal Circuit, Lawrence M. Sung

Faculty Scholarship

No abstract provided.

Precision Farming Protocols. Part 2. Comparison Of Sampling Approaches For Precision Phosphorus Management, David E. Clay, Jiyul Chang, C. Gregg Carlson, Doug Malo, Sharon A. Clay, Mike Ellsbury

Agronomy, Horticulture and Plant Science Faculty Publications

Research is needed to compare the different techniques for developing site‐specific phosphorus (P) recommendations on a field‐wide basis. The objective of this study was to determine the impact different techniques for developing site‐specific P recommendation maps on yield and profitability. Enterprise analysis combined with a crop simulation model and detailed field characterization was used to estimate the value of spatial P information in a system where N was not limiting. The systems evaluated were continuous corn (Zea mays) and corn and soybean (Gfycine max) rotations where sampling and fertilizer applications were applied annually and semi‐annually, respectively. The sampling techniques tested …

Mapping The Boulder City Wetlands Using A Global Positioning System (Gps) And A Geographic Information System (Gis), Jennifer Lea Bishop

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Boulder City Wetlands is a constructed wetlands park located in Boulder City, Nevada, approximately 23 miles southeast of Las Vegas, Nevada. Currently, a baseline study of water quality is being conducted in the Boulder City Wetlands. This baseline study of the wetlands is an important step in understanding the development of the Boulder City Wetlands over time. As wastewater is eventually introduced into the existing community tap water running through the wetlands, it is expected that the nitrogen within the water will enhance the growth of vegetation in the surrounding area. Comparing the vegetation growth over time is only …