Digital Commons Network^™

Commentary: Considerations For Use Of Racial/Ethnic Classification In Etiologic Research, Jay S. Kaufman, Richard S. Cooper

Faculty Publications

Numerous authors have critiqued the use of race as an etiologic quantity in medical research. Despite this criticism, the use of variables encoding racial/ethnic categorization has increased in epidemiology, and most researchers agree that important variation in disease risk is captured by this classification system. Previous discussions have generally neglected to articulate guidelines for appropriate use of racial/ethnic information in etiologic research. The authors summarize the logical, conceptual, and practical problems associated with the "ethnic paradigm" as currently applied in biomedical sciences and offer a set of methodological recommendations toward more valid use of racial/ethnic classification in etiologic studies. These …

Kaufman And Copper Respond To "Race,'Racism,And The Practice Of Epidemiology, Jay S. Kaufman, Richard S. Cooper

Faculty Publications

No abstract provided.

Function Of Escherichia Coli Biotin Carboxylase Requires Catalytic Activity Of Both Subunits Of The Homodimer, Kamala Janiyani, Tee Bordelon, Grover L. Waldrop, John E. Cronan

Faculty Publications

Biotin carboxylase catalyzes the ATP-dependent carboxylation of biotin and is one component of the multienzyme complex acetyl-CoA carboxylase that catalyzes the first committed step in fatty acid synthesis. The Escherichia coli biotin carboxylase is readily isolated from the other components of the acetyl-CoA carboxylase complex such that enzymatic activity is retained. The three-dimensional structure of biotin carboxylase, determined by x-ray crystallography, demonstrated that the enzyme is a homodimer consisting of two active sites in which each subunit contains a complete active site. To understand how each subunit contributes to the overall function of biotin carboxylase, we made hybrid molecules in …

Green Electrochemistry. Examples And Challenges, Michael A. Matthews

Faculty Publications

Electrochemical methods have been proposed for synthesis of organic compounds, including conversion of CO₂. Such methods may provide a basis for environmentally friendly and sustainable methods for chemical production. Nevertheless, electrochemical syntheses are not widely utilized. Several examples of ongoing research are presented that illustrate both the opportunities as well as the challenges associated with the utilization of electrochemistry for green chemical manufacturing.

The Scientific Foundations Of Habitat Conservation Plans: A Quantitative Assessment, Elaine K. Harding, Elizabeth E. Crone, Bret D. Elderd, Jonathan M. Hoekstra, Alexa J. Mckerrow, John D. Perrine, Jim Regetz, Leslie J. Rissler, Amanda G. Stanley, Eric L. Walters

Faculty Publications

The number of habitat conservation plans (HCP) has risen dramatically since the first plan was written over 18 years ago. Until recently, no studies have quantitatively investigated the scientific foundations underlying these documents. As part of a larger study of HCPs, we examined 43 plans primarily to assess the availability and use of scientific data and secondarily to determine the extent of involvement by, and influence of independent scientists within the process. Specifically, our analysis focused on five key steps taken when an HCP is developed: assessing status of a species, determining take, predicting the project effects, mitigating for those …

Improving The Hopfield Network Through Beam Search, Tony R. Martinez, Xinchuan Zeng

Faculty Publications

In this paper we propose a beam search mechanism to improve the performance of the Hopfield network for solving optimization problems. The beam search readjusts the top M (M > 1) activated neurons to more similar activation levels in the early phase of relaxation, so that the network has the opportunity to explore more alternative, potentially better solutions. We evaluated this approach using a large number of simulations (20,000 for each parameter setting), based on 200 randomly generated city distributions of the 10-city traveling salesman problem. The results show that the beam search has the capability of significantly improving the network …

The Need For Small Learning Rates On Large Problems, Tony R. Martinez, D. Randall Wilson

Faculty Publications

In gradient descent learning algorithms such as error backpropagation, the learning rate parameter can have a significant effect on generalization accuracy. In particular, decreasing the learning rate below that which yields the fastest convergence can significantly improve generalization accuracy, especially on large, complex problems. The learning rate also directly affects training speed, but not necessarily in the way that many people expect. Many neural network practitioners currently attempt to use the largest learning rate that still allows for convergence, in order to improve training speed. However, a learning rate that is too large can be as slow as a learning …

Site-Directed Mutagenesis Of Atp Binding Residues Of Biotin Carboxylase: Insight Into The Mechanism Of Catalysis, Valerie Sloane, Carol Z. Blanchard, Frankie Guillot, Grover L. Waldrop

Faculty Publications

Acetyl-CoA carboxylase catalyzes the first committed step in fatty acid synthesis in all plants, animals, and bacteria. The Escherichia coli form is a multimeric protein complex consisting of three distinct and separate components: biotin carboxylase, carboxyltransferase, and the biotin carboxyl carrier protein. The biotin carboxylase component catalyzes the ATP-dependent carboxylation of biotin using bicarbonate as the carboxylate source and has a distinct architecture that is characteristic of the ATP-grasp superfamily of enzymes. Included in this superfamily are D-Ala D-Ala ligase, glutathione synthetase, carbamyl phosphate synthetase, N⁵-carboxyaminoimidazole ribonucleotide synthetase, and glycinamide ribonucleotide transformylase, all of which have known three-dimensional …

Embryonic Stem Cell Research As An Ethical Issue: On The Emptiness Of Symbolic Value, Kevin Quinn

Faculty Publications

The ability to generate a wide variety of stem cell lines (in relatively renewable tissue cultures) opens up a whole new world of breathtaking possibilities for science and medicine. The possibilities include: "in vitro studies of normal embryo-genesis, human gene discovery, and drug and teratogen testing and as a renewable source of cells for tissue transplantation, cell replacement, and gene therapies." But it also opens up a world of complications.

Human EG and ES cells must be recovered from aborted fetuses or live embryos. Because primordial gonadal tissue is removed from fetuses after their death, the derivation of EO cells …

A Primer On Adoption Law, Douglas E. Abrams

Faculty Publications

No abstract provided.

Bioavailability: On The Frontiers Of Science And Law In Cleanup Methodologies For Contamination, Linda A. Malone

Faculty Publications

No abstract provided.

Experimental Evaluation Of Vitellogenin As A Predictive Biomarker For Reproductive Disruption, Ann Oliver Cheek, Thea Hoexum Brouwer, Suzanne Carroll, Steve Manning, John A. Mclachlan, Marius Brouwer

Faculty Publications

Vitellogenin (VTG) synthesis in male oviparous vertebrates is used as an indicator of environmental estrogen exposure, but the relationship between elevated VTG levels and the effects of environmental estrogens on reproductive success are poorly understood. To examine whether altered VTG expression predicts reproductive impairment, we exposed medaka (Oryzias latipes) for 2 or 8 weeks posthatch to 0, 0.5, 1.0, 2.5, and 7.5 ppb of the environmental estrogen o,p ' -DDT. Fish were sampled 2, 4, and 8 weeks after hatch to examine VTG expression and gonad development. After exposure, fish were transferred to clean water, grown to sexual maturity, and …

Scaling Gridded River Networks For Macroscale Hydrology: Development, Analysis, And Control Of Error, Balazs M. Fekete, Charles J. Vorosmarty, Richard B. Lammers

Faculty Publications

A simple and robust river network scaling algorithm (NSA) is presented to rescale fine‐resolution networks to any coarser resolution. The algorithm was tested over the Danube River basin and the European continent. Coarse‐resolution networks, at 2.5, 5, 10, and 30 min resolutions, were derived from higher‐resolution gridded networks using NSA and geomorphometric attributes, such as river order, shape index, and width function. These parameters were calculated and compared at each resolution. Simple scaling relationships were found to predict decreasing river lengths with coarser‐resolution data. This relationship can be used to correct river length as a function of grid resolution. The …

Molecular Diversity, Structure And Domestication Of Grasses, Edward S. Buckler Iv, Jeffry M. Thornsberry, Stephen Kresovich

Faculty Publications

Over the last 10,000 years, crop domestication has been the single most important human cultural development. Grasses are prominent among these crops, and provide the vast majority of the world's food. Similar traits have been selected during the domestication and breeding of these critically important grasses, and since they share a similar complement of genes, the same set of genes may have been selected. Even though the process of domestication occurred over the same 5000 to 10,000 year period, the domesticated grasses have major differences in genome structure, diversity, and life history. Molecular investigations of grass domestication have succeeded in …

Shape Imprinting Due To Variable Disulfide Bonds In Polyacrylamide Gels, Andrew B. Greytak, Alexander Y. Grosberg, Toyoichi Tanaka

Faculty Publications

Through the use of variable disulfide crosslinkers, we have created polyacrylamide gels whose shape can be altered after polymerization. N,N'-bisacryloylcystamine is incorporated as a crosslinker, along with a smaller amount of a permanent crosslinker. After polymerization, the disulfide bonds are cleaved into thiols through reduction. By reoxidizing the thiols with the gel held in a new macroscopic shape, a new set of disulfide bonds is formed, and the gel is forced to adopt the new shape. Retension of the new shape improves with greater distortion from the original shape, as well as with increased concentration of variable …

Chloropigment Distribution And Transport On The Inner Shelf Off Duck, North Carolina, Eurico J. D'Sa, Steven E. Lohrenz, James H. Churchill, Vernon L. Asper, John L. Largier, Albert J. Williams Iii

Faculty Publications

The distribution and movement of chloropigments (chlorophylls and associated degradation products) in the bottom boundary layer near Duck, North Carolina, were examined during July and August 1994. Time series of chloropigment fluorescence, current velocity, and surface wave properties were acquired from instruments mounted on a bottom tripod set at 20 m depth. These data were combined with moored current meter measurements, meteorological data, and shipboard surveys in a comparative assessment of physical processes and chloropigment distribution over a wide range of temporal and spatial scales. Two dominant scales of chloropigment variation were observed. On numerous occasions, small-scale (order m) structure …

Near-Field Scanning Optical Microscopy (Nsom) Studies Of The Relationship Between Interchain Interactions, Morphology, Photodamage, And Energy Transport In Conjugated Polymer Films, Thuc Quyen Nguyen, Benjamin J. Schwartz, Richard D. Schaller, Justin C. Johnson, Lynn F. Lee, Louis H. Haber, Richard J. Saykally

Faculty Publications

It is becoming increasingly clear that the way in which a conjugated polymer film is cast affects the interactions between polymer chains and thus the optical and electrical properties of the film. Given that conjugated polymer films cast in different ways also show different nanometer-scale surface topographies, the question that arises is: What is the correlation between surface topography, local chain packing, and the local electronic properties of a conjugated polymer film? In this paper, we address this question using fluorescence near-field scanning optical microscopy (NSOM) to examine films of poly(2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene) (MEH-PPV) that were prepared in different ways. The …

How To Evaluate The Financial Maturity Of Timber, Steven H. Bullard

Faculty Publications

If you own merchantable timber, you face an important question on a continuing basis: "Should I sell my timber now or should I wait?" How you respond to this question involves many issues, of course, including stand conditions, site conditions, and other physical and biological considerations. For many landowners, however, financial considerations are also extremely important. In this article we discuss "financial maturity" as a specific tool that can be used to help evaluate timber harvest decisions.

Restoration Of Fish Habitat In The Provo River: A Multispecies Approach, Mark C. Belk

Faculty Publications

Historically, the Provo river, located in Utah and Wasatch Cos., Utah, was a clear-flowing stream with headwaters in the western edge of the Uinta mountains that emptied into Utah Lake near Provo, Utah. The river had a wide flood plain and a braided channel, especially in the Heber valley and Utah valley areas. Diversion of water and construction of water storage facilities began in the late 1800's and intensified in the 1900's. Deer Creek reservoir was built in the 1950's and diking and channelization continued until the construction of Jordanelle reservoir in the late 1980's. The Provo River Restoration Project, …

Comparative Phylogeography Of Mesoamerican Highland Rodents: Concerted Versus Independent Response To Past Climatic Fluctuations, Duke S. Rogers, Jack Sullivan, Elizabeth Arellano

Faculty Publications

The phylogeography of Sumichrast's harvest mouse (Reithrodontomys sumichrasti) was examined through maximumlikelihood and parsimony analyses of 1,130 bp of mitochondrial Cytochrome b sequence data from 43 individuals. The phylogeography of this Middle American highland forest-dwelling species was compared to that previously published for the codistributed Aztec deer mouse complex (Peromyscus aztecus/Peromyscus hylocetes complex) in order to test competing hypotheses of concerted versus independent responses of codistributed forms to past climatic fluctuations. Qualitatively, there were strong similarities in the phylogeographic patterns of the two groups, yet there were also areas of incongruence. Likelihood-ratio tests (Kishino-Hasegawa-Templeton and parametric bootstrap tests) indicated that …

Controls On Floc Size In A Continental Shelf Bottom Boundary Layer, Paul S. Hill, George Voulgaris, John H. Trowbridge

Faculty Publications

Simultaneous in situ observations of floc size, waves, and currents in a continental shelf bottom boundary layer do not support generally accepted functional relationships between turbulence and floc size in the sea. In September and October 1996 and January 1997, two tripods were deployed in 70 m of water on the continental shelf south of Woods Hole, Massachusetts. On one a camera photographed particles in suspension 1.2 m above the bottom that had equivalent circular diameters larger than 250 um, and on the other, three horizontally displaced acoustic current meters measured flow velocity 0.35 m above the bottom. The …

Alu Insertion Polymorphisms And The Genetic Structure Of Human Populations From The Caucasus, Ivane Nasidze, Gregory M. Risch, Myles Robichaux, Stephen T. Sherry, Mark A. Batzer, Mark Stoneking

Faculty Publications

An analysis of 8 Alu insertion loci (ACE, TPA25, PV92, APO, FXIIIB, D1, A25, B65) has been carried out in six populations from the Caucasus, including Indo-European-speaking Armenians; Altaic-speaking Azerbaijanians; North Caucasian-speaking Cherkessians, Darginians, and Ingushians; and South Caucasian (Kartvelian)-speaking Georgians. The Caucasus populations exhibit low levels of within-population variation and high levels of between-population differentiation, with the average Fst value for the Caucasus of 0.113, which is almost as large as the Fst value of 0.157 for worldwide populations. Maximum likelihood tree and principal coordinate analyses both group the Caucasus populations with European populations. Neither geographic nor linguistic relationships …

Group I Metabotropic Glutamate Receptors Are Expressed In The Chicken Retina And By Cultured Retinal Amacrine Cells, Kathryn M. Kreimborg, Martha L. Lester, Kathryn F. Medler, Evanna L. Gleason

Faculty Publications

Glutamate is well established as an excitatory neurotransmitter in the vertebrate retina. Its role as a modulator of retinal function, however, is poorly understood. We used immunocytochemistry and calcium imaging techniques to investigate whether metabotropic glutamate receptors are expressed in the chicken retina and by identified GABAergic amacrine cells in culture. Antibody labeling for both metabotropic glutamate receptors 1 and 5 in the retina was consistent with their expression by amacrine cells as well as by other retinal cell types. In double-labeling experiments, most metabotropic glutamate receptor 1-positive cell bodies in the inner nuclear layer also label with anti-GABA antibodies. …

Seasonal Variation Of The North Atlantic Current, Max I. Yaremchuk, Dmitri A. Nechaev, Keith R. Thompson

Faculty Publications

The seasonal circulation of the upper 1000 m of the North Atlantic between 40 degrees -55 degreesN and 20 degrees -40 degreesW is calculated using the traditional dynamic method and a circulation model with a density field that evolves with the flow. The model is of finite difference form and is based on dynamics that describe the nonlinear evolution of the ocean at low Rossby number. The model is controlled by initial and boundary conditions that include air-sea buoyancy and momentum fluxes. The model is run in two ways: with controls specified directly from observations and with controls inferred by …

Of Manatees, Mangroves, And The Mississippi River: Is There An Estuarine Signature For The Gulf Of Mexico?, R. Eugene Turner

Faculty Publications

Important parameters of estuarine variability include morphology, flushing times, nutrient loading rates, and wetland: water ratios. This variability both reflects and disguises underlying relationships between the physics and biology of estuaries, which this comparative analysis seeks to reveal, using the Gulf of Mexico (GOM) estuaries as a starting point. A question used to focus this analysis is: are the GOM estuaries unique? The GOM receives the Mississippi River, a uniquely large, world-class river, which dominates the freshwater and nutrient inflows to the GOM continental shelf, whose margins include 35 major estuarine systems. These GOM estuaries have 28% and 41% of …

Simultaneous Capture And Mineralization Of Coal Combustion Flue Gas Carbon Dioxide (Co2), Morris D. Argyle, Katta J. Reddy, Sanil John, Hollis Weber, Pradip Bhattacharyya, David T. Taylor, Mikol Christensen, Thomas Foulke, Paul Fahlsing

Faculty Publications

The mineral carbonation, a process of converting CO2 into stable minerals (mineralization), has been studied extensively to capture and store CO2. However, most of the mineral carbonation studies have been largely investigated at lab scale. Preliminary and pilot scale studies for accelerated mineral carbonation (AMC) were conducted at one of the largest coal-fired power plants (2120 MW) in the USA by reacting flue gas with fly ash particles in a fluidized bed reactor. In the preliminary experiments, flue gas CO2 and SO2 concentrations decreased from 13.0 to 9.6% and from 107.8 to 15.1 ppmv, respectively during the first 2 min. …

Novel Transactivation Domain In Erythroid Kruppel-Like Factor (Eklf), Kumar Pandya, David Donze, Tim M. Townes

Faculty Publications

Erythroid Kruppel-like Factor (EKLF) is an erythroid-specific transcription factor that plays a critical role in γ- to β-globin gene switching during development. To identify essential domains required for EKLF transactivation function, we cotransfected a human erythroleukemia cell line (K562) with a locus control region γ/Luc-β/Cat reporter and an EKLF expression vector. In this assay EKLF mediates a 500-fold induction of β/CAT expression compared with controls. To map essential transactivation domains, progressive NH2-terminal and internal deletion mutants of EKLF were constructed. All EKLF mutants were expressed at wild-type levels, localized to the nucleus, and bound DNA. When mutant EKLF proteins were …

Interferon-Γ-Induced Regulation Of Peroxisome Proliferator-Activated Receptor Γ And Stats In Adipocytes, Kyle J. Waite, Z. Elizabeth Floyd, Patricia Arbour-Reily, Jacqueline M. Stephens

Faculty Publications

Interferon-γ (IFN-γ) is known primarily for its roles in immunological responses but also has been shown to affect fat metabolism and adipocyte gene expression. To further investigate the effects of IFN-γ on fat cells, we examined the effects of this cytokine on the expression of adipocyte transcription factors in 3T3-L1 adipocytes. Although IFN-γ regulated the expression of several adipocyte transcription factors, IFN-γ treatment resulted in a rapid reduction of both peroxisome proliferator-activated receptor (PPAR) protein and mRNA. A 48-h exposure to IFN-γ also resulted in a decrease of both CCAAT/enhancer-binding α and sterol regulatory element binding protein (SREBP-1) expression. The …

Expression Characteristics Of The Transfer-Related Kilb Gene Product Of Streptomyces Plasmid Pij101: Implications For The Plasmid Spread Function, G. S. Pettis, N. Ward, K. L. Schully

Faculty Publications

Intermycelial transfer of Streptomyces plasmid pIJ101 occurs prior to cellular differentiation and is mediated by plasmid functions that are also required for production of zones of growth-inhibited recipient cells (i.e., pocks) that develop around individual donors during mating on agar medium. Several other pIJ101 functions, including that of the kilB gene, whose unregulated expression on pIJ101 is lethal, are required for normal pock size and so have been postulated to mediate intramycelial spread of the plasmid throughout recipient cells. Using antibodies raised against a KilB fusion protein expressed in Escherichia coli, native KilB protein was detected throughout development of pIJ101-containing …

Optimum Timing Of Insecticide Applications Against Diamondback Moth Plutella Xylostella In Cole Crops Using Threshold Catches In Sex Pheromone Traps, Gadi Venkata Prasad Reddy, Angel Guerrero

Faculty Publications

Field trials were conducted in cabbage (Brassica oleracea var capitata), cauliflower (B oleracea var botrytis) and knol khol (B oleracea gongylodes) crops at two different locations in Karnataka State (India) to optimize the timing of insecticide applications to control the diamondback moth, Plutella xylostella, using sex pheromone traps. Our results indicate that applications of cartap hydrochloride as insecticide during a 12-24h period after the pheromone traps had caught on average 8, 12 and 16 males per trap per night in cabbage, cauliflower and knol khol, respectively, were significantly more effective than regular insecticide sprays at 7, 9, 12 or 15 …