Showing papers by "Oklahoma State University–Stillwater published in 2004"
TL;DR: This article developed and tested a model that explains how service-worker customer orientation affects several important job responses, including perceived job fit, job satisfaction, commitment to the firm, and organizational citizenship behaviors.
Abstract: Implementation of the marketing concept in service firms is accomplished through individual service employees and their interactions with customers. Although prior research has established a link between service-worker customer orientation and performance outcomes, little research has addressed other potentially important outcomes of customer orientation. Drawing from the literature on person‐situation interaction and fit theory, the authors develop and test a model that explains how service-worker customer orientation affects several important job responses, including perceived job fit, job satisfaction, commitment to the firm, and organizational citizenship behaviors. Across three field studies in two distinct services industries, the results indicate that the positive influence of customer orientation on certain job responses is stronger for service workers who spend more time in direct contact with customers than for workers who spend less time with customers. The authors discuss the implications of the results for services marketing managers and researchers.
815 citations
TL;DR: In this paper, the authors proposed a general approach and a set of indices to assess some of the technical benefits in a quantitative manner, including voltage profile improvement, line loss reduction, environmental impact reduction, and DG benefit index.
Abstract: Recent changes in the electric utility infrastructure have created opportunities for many technological innovations, including the employment of distributed generation (DG) to achieve a variety of benefits. After a brief discussion of the benefits, this paper proposes a general approach and a set of indices to assess some of the technical benefits in a quantitative manner. The indices proposed are: 1) voltage profile improvement index; 2) line-loss reduction index; 3) environmental impact reduction index; and 4) DG benefit index. Simulation results obtained using a simple 12-bus test system and a radial system are presented and discussed to illustrate the value and usefulness of the proposed approach.
707 citations
TL;DR: In this article, the authors used a simple experiment to show that fitting to a power law distribution by using graphical methods based on linear fit on the log-log scale is biased and inaccurate.
Abstract: This short communication uses a simple experiment to show that fitting to a power law distribution by using graphical methods based on linear fit on the log-log scale is biased and inaccurate. It shows that using maximum likelihood estimation (MLE) is far more robust. Finally, it presents a new table for performing the Kolmogorov-Smirnov test for goodness-of-fit tailored to power-law distributions in which the power-law exponent is estimated using MLE. The techniques presented here will advance the application of complex network theory by allowing reliable estimation of power-law models from data and further allowing quantitative assessment of goodness-of-fit of proposed power-law models to empirical data.
659 citations
TL;DR: Current research is focused on the proteolytic activation of prophenoloxidase (proPO) – a reaction implicated in melanotic encapsulation, wound healing, and protein cross‐linking, and three proPO‐activating proteinases, each of which requires serine proteinase homologs as a cofactor for generating active phenol oxidase.
Abstract: Many innate immune mechanisms are conserved throughout the animal kingdom. Manduca sexta, a widely used model for insect biochemical research, employs these mechanisms to defend against invading pathogens and parasites. We have isolated from M. sexta hemolymph a group of proteins (hemolin, peptidoglycan recognition proteins, beta-1,3-glucan recognition proteins, and C-type lectins), which serve as a surveillance mechanism by binding to microbial surface molecules (e.g. peptidoglycan, lipopolysaccharide, lipoteichoic acid, and beta-1,3-glucan). The binding triggers diverse responses such as phagocytosis, nodule formation, encapsulation, melanization, and synthesis of anti-microbial peptides/proteins. Some of these responses are mediated and coordinated by serine proteinase cascades, analogous to the complement system in mammals. Our current research is focused on the proteolytic activation of prophenoloxidase (proPO)--a reaction implicated in melanotic encapsulation, wound healing, and protein cross-linking. We have isolated three proPO-activating proteinases, each of which requires serine proteinase homologs as a cofactor for generating active phenoloxidase. The proteinases and proteinase-like molecules, containing one to two clip domains at their amino-terminus, are acute-phase proteins induced upon an immune challenge. Inhibitory regulation of the proteinases by serpins and association of the proteinase homologs with a bacteria-binding lectin are important for ensuring a localized defense response. Additional serine proteinases expressed in M. sexta hemocytes and fat body have been discovered. Future research efforts will be aimed at elucidating the proteinase cascade for proPO activation and investigating the roles of proteinases in other immune responses such as processing of plasmatocyte-spreading peptide.
649 citations
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TL;DR: In this paper, a detailed description of the CRM process is provided along with a comprehensive framework intended to aid marketers in their quest to achieve CRM success, which is best conceptualized as an ongoing process that involves the development and leveraging of market intelligence for the purpose of building and maintaining a profit-maximizing portfolio of customer relationships.
Abstract: Prompted – in part – by the highly publicized failure of customer relationship management (CRM) initiatives, academic research on CRM has begun to flourish. While numerous studies have yielded important insights, the extant CRM literature appears to be inconsistent and is highly fragmented due, primarily, to the lack of a common conceptualization. Thus, in order to help advance a cohesive body of knowledge on this topic of growing interest and importance, this paper attempts to provide a clear and accurate delineation of CRM’s domain. Following the review and analysis of process, strategy, philosophy, capability and technology-based CRM perspectives, the authors propose that the phenomenon is best conceptualized as an ongoing process that involves the development and leveraging of market intelligence for the purpose of building and maintaining a profit-maximizing portfolio of customer relationships. Based on the proposed conceptualization, a detailed description of the CRM process is provided along with a comprehensive framework intended to aid marketers in their quest to achieve CRM success.
637 citations
TL;DR: In this article, the authors investigated the relationship between service quality and customer satisfaction within the setting of online securities brokerage services and found that primary service quality dimensions leading to online customer satisfaction are closely related to traditional services while key factors leading to dissatisfaction are tied to information systems quality.
Abstract: This exploratory research intends to extend our understanding of service quality and customer satisfaction within the setting of online securities brokerage services. Based upon conceptual frameworks from the areas of services marketing and information systems management, the authors uncovered 52 items across 16 major service quality dimensions by content analysis of 740 customer reviews. The results indicate that primary service quality dimensions leading to online customer satisfaction, with the exception of ease of use, are closely related to traditional services while key factors leading to dissatisfaction are tied to information systems quality. In addition, major drivers of satisfaction and dissatisfaction are identified at the sub‐dimensional level. Theoretical contribution and managerial implications of the findings are further discussed.
552 citations
TL;DR: In this paper, a model of the fire-grazing interaction is proposed, which argues that grazing and fire interact through a series of positive and negative feedbacks to cause a shifting mosaic of vegetation pattern across the landscape.
Abstract: Summary 1. Management of rangelands has long operated under the paradigm of minimizing spatially discrete disturbances, often under the objective of reducing inherent heterogeneity within managed ecosystems. Management of grazing animals has focused on uniform distribution of disturbance, so that no areas are heavily disturbed or undisturbed (i.e. management to the ‘middle’). 2. A model of the fire‐grazing interaction argues that grazing and fire interact through a series of positive and negative feedbacks to cause a shifting mosaic of vegetation pattern across the landscape. This interaction was important in the evolution of species in the North American Great Plains grasslands. This approach has the potential to serve as an ecological-based model for management of grasslands with a long evolutionary history of grazing. 3. We compared a heterogeneity-based approach, in which fire is applied to discrete patches, with typical homogeneity-based land management in the North American Great Plains, to determine if patch burning followed by focal grazing creates a shifting mosaic pattern of vegetation structure and composition. 4. Our data suggest that spatially discrete fires promote focal grazing, where grazing animals devote 75% of grazing time within the one-third of the area that has been burned within the past year. These focal disturbances cause local changes in the plant community and increase patch-level heterogeneity across landscapes. As the focal disturbance is shifted to other patches over time, successional processes lead to changes in local plant communities and the patchwork landscape can be described as a shifting mosaic. 5. A patch-dynamic approach can be accomplished in the tallgrass prairie through applying spatially discrete fires and allowing animals free access to a diversity of landscape elements that vary in time since focal disturbance. This increases heterogeneity across the landscape, a variable that has been shown to be critical to some wildlife species as well as the structure and function of grassland ecosystems. 6. Synthesis and applications. Our study demonstrates that the fire-grazing model may be useful for generating heterogeneity in grassland management. Discrete fires are applied to patches, and patchy grazing by herbivores promotes a shifting vegetation mosaic across the landscape. Furthermore, application of the model has the potential of increasing the area of rangelands under management for conservation purposes, because livestock production is maintained at a level similar to traditional management. So, by managing transient focal patches that move through the landscape, heterogeneity has the potential to be a central paradigm for managing landscapes for multiple objectives, such as biodiversity and agricultural productivity.
523 citations
TL;DR: It is demonstrated that expression of these genes is not embryo-specific, validated a strategy for identifying interacting proteins through complementation with epitope-tagged proteins, and discussed the value of EMB genes in identifying novel proteins associated with important plant processes.
Abstract: A long-term goal of Arabidopsis research is to define the minimal gene set needed to produce a viable plant with a normal phenotype under diverse conditions. This will require both forward and reverse genetics along with novel strategies to characterize multigene families and redundant biochemical pathways. Here we describe an initial dataset of 250 EMB genes required for normal embryo development in Arabidopsis. This represents the first large-scale dataset of essential genes in a flowering plant. When compared with 550 genes with other knockout phenotypes, EMB genes are enriched for basal cellular functions, deficient in transcription factors and signaling components, have fewer paralogs, and are more likely to have counterparts among essential genes of yeast (Saccharomyces cerevisiae) and worm (Caenorhabditis elegans). EMB genes also represent a valuable source of plant-specific proteins with unknown functions required for growth and development. Analyzing such unknowns is a central objective of genomics efforts worldwide. We focus here on 34 confirmed EMB genes with unknown functions, demonstrate that expression of these genes is not embryo-specific, validate a strategy for identifying interacting proteins through complementation with epitope-tagged proteins, and discuss the value of EMB genes in identifying novel proteins associated with important plant processes. Based on sequence comparison with essential genes in other model eukaryotes, we identify 244 candidate EMB genes without paralogs that represent promising targets for reverse genetics. These candidates should facilitate the recovery of additional genes required for seed development.
475 citations
TL;DR: In this article, a cancellation of absorption occurs on resonance for two (or any even number of) coupled optical resonators, due to mode splitting and classical destructive interference, particularly when the resonator finesse is large and the loss in resonator farthest from the excitation waveguide is small.
Abstract: We demonstrate that a cancellation of absorption occurs on resonance for two (or any even number of) coupled optical resonators, due to mode splitting and classical destructive interference, particularly when the resonator finesse is large and the loss in the resonator farthest from the excitation waveguide is small. The linewidth and group velocity of a collection of such coupled-resonator structures may be decreased by using larger resonators of equal size, by using larger resonators of unequal size where the optical path length of the larger resonator is an integer multiple of that of the smaller one, or by using a larger number of resonators per structure. We explore the analogy between these effects and electromagnetically-induced transparency in an atomic system.
461 citations
TL;DR: The far-infrared absorption and index of refraction of high resistivity, float-zone, crystalline silicon has been measured by terahertz time-domain spectroscopy.
Abstract: The far-infrared absorption and index of refraction of high-resistivity, float-zone, crystalline silicon has been measured by terahertz time-domain spectroscopy. The measured new upper limit for the absorption of this most transparent dielectric material in the far infrared shows unprecedented transparency over the range from 0.5 to 2.5 THz and a well-resolved absorption feature at 3.6 THz. The index of refraction shows remarkably little dispersion, changing by only 0.0001 over the range from 0.5 to 4.5 THz.
412 citations
TL;DR: In order to be used in the site-specific ecological risk assessment of chemicals, effects concentrations must be developed from laboratory toxicity tests based on exposure estimates utilizing techniques that measure the bioavailable fraction of chemicals in soil, not total chemical concentrations.
TL;DR: Three chemical immobilization materials, agricultural limestone (AL), mineral rock phosphate (RP), and diammonium phosphate (DAP), were evaluated using solute transport experiments to determine their ability to reduce subsurface heavy metal transport in a smelter contaminated soil.
TL;DR: In this article, the authors analyze how a student teacher negotiated the different conceptions of teaching that provided the expectations for good instruction in her university and the site of her student teaching and how her effort to reconcile the different belief systems affected her identity as a teacher.
Abstract: This article analyzes how Sharon, a student teacher, negotiated the different conceptions of teaching that provided the expectations for good instruction in her university and the site of her student teaching and how her effort to reconcile the different belief systems affected her identity as a teacher. The key settings of Sharon’s experience were the university program, her third-grade class at Harding Elementary, and her first teaching job. During student teaching, Sharon experienced frustrating tensions because her cooperating teacher provided little room for experimentation, mentoring instead with a mimetic approach. When in her first job, Sharon had the opportunity to resolve instructional problems with greater authority. We see tensions that require a socially contextualized intellectual resolution rather than simply one of relational accommodation as potentially productive in creating environments conductive to the formation of a satisfying teaching identity.
TL;DR: This work presents the largest survey to date, to the authors' knowledge, of the heritability of gene-expression traits in segregating human populations, and views clusters or networks based on genetic correlation measures and shared QTLs as potentially novel insights into the relationship among genes that may underlie complex traits.
Abstract: Combining genetic inheritance information, for both molecular profiles and complex traits, is a promising strategy not only for detecting quantitative trait loci (QTLs) for complex traits but for understanding which genes, pathways, and biological processes are also under the influence of a given QTL. As a primary step in determining the feasibility of such an approach in humans, we present the largest survey to date, to our knowledge, of the heritability of gene-expression traits in segregating human populations. In particular, we measured expression for 23,499 genes in lymphoblastoid cell lines for members of 15 Centre d'Etude du Polymorphisme Humain (CEPH) families. Of the total set of genes, 2,340 were found to be expressed, of which 31% had significant heritability when a false-discovery rate of 0.05 was used. QTLs were detected for 33 genes on the basis of at least one P value <.000005. Of these, 13 genes possessed a QTL within 5 Mb of their physical location. Hierarchical clustering was performed on the basis of both Pearson correlation of gene expression and genetic correlation. Both reflected biologically relevant activity taking place in the lymphoblastoid cell lines, with greater coherency represented in Kyoto Encyclopedia of Genes and Genomes database (KEGG) pathways than in Gene Ontology database pathways. However, more pathway coherence was observed in KEGG pathways when clustering was based on genetic correlation than when clustering was based on Pearson correlation. As more expression data in segregating populations are generated, viewing clusters or networks based on genetic correlation measures and shared QTLs will offer potentially novel insights into the relationship among genes that may underlie complex traits.
TL;DR: Thermogravimetric analyses and near-infrared and Raman spectra indicate that the side walls of the SWNT were lightly functionalized by the nitric acid treatment and that the degree of functionalization did not change significantly during the formation of initiator or during the polymerization.
Abstract: Polymer brushes with single-walled carbon nanotubes (SWNT) as backbones were synthesized by grafting n-butyl methacrylate (nBMA) from the ends and sidewalls of SWNT via atom transfer radical polymerization (ATRP). Carboxylic acid groups on SWNT were formed by nitric acid oxidation. The ATRP initiators were covalently attached to the SWNT by esterification of 2-hydroxyethyl 2'-bromopropionate with carboxylic acid groups. Methyl 2-bromopropionate (MBP) was added as free initiator during the brush preparation to control growth of the brushes and to monitor the polymerization kinetics. Size-exclusion chromatography (SEC) results show that the molecular weight of free poly(n-butyl methacrylate) (PnBMA) increased linearly with nBMA monomer conversion. PnBMA cleaved from the SWNT after high conversion had the same molecular weight as PnBMA produced in solution. Thermogravimetric analyses (TGA) show that the amount of PnBMA grown from the SWNT increased linearly with the molecular weight of the free PnBMA. The most highly PnBMA-functionalized SWNT dissolve in 1,2-dichlorobenzene, chloroform, and tetrahydrofuran, and solubility increases with the amount of PnBMA bound to SWNT. Near-infrared and Raman spectra indicate that the side walls of the SWNT were lightly functionalized by the nitric acid treatment and that the degree of functionalization of the SWNT did not change significantly during the formation of initiator or during the polymerization. Atomic force microscopy (AFM) images show contour lengths of the SWNT brushes on a mica surface from 200 nm to 2.0 microm and an average height of the backbone of 2-3 nm, indicating that the bundles of original SWNT were broken into individual tubes by functionalization and polymerization.
TL;DR: In this paper, single-walled carbon nanotubes (SWNT) were functionalized with polystyrene (PSt) by grafting to and grafting from methods.
Abstract: Single-walled carbon nanotubes (SWNT) were functionalized with polystyrene (PSt) by grafting to and grafting from methods. PSt-N3 with designed molecular weight and narrow molecular weight distribution was synthesized by atom transfer radical polymerization (ATRP) of styrene (St) followed by end group transformation and then added to SWNT. The grafting from functionalization was achieved by ATRP of St using 2-bromopropionate groups immobilized SWNT as initiator. Methyl 2-bromopropionate (MBP) was added as free initiator to control the chain propagation on SWNT during the polymerization. Raman and near-IR spectra show that PSt was covalently attached to the sidewalls of SWNT by the grafting to approach, and the degree of functionalization was about 1 in 48 SWNT carbon atoms as determined by thermogravimetric analyses (TGA). In the grafting from approach, size exclusion chromatography (SEC) results show that the molecular weight of free St increased linearly with St conversion, and the PSt cleaved from the ...
TL;DR: In this paper, the authors investigate whether demographic and behavioral characteristics differ significantly among groups of online virtual community members; identify factors that affect the community members' loyalty; and determine if the loyalty to an online virtual communities would lead members to purchase products.
TL;DR: Empirical results indicate that HFM is relatively less accurate and RBFN is relatively more reliable for the weather forecasting problem, while the ensemble of neural networks produced the most accurate forecasts.
Abstract: This study presents the applicability of an ensemble of artificial neural networks (ANNs) and learning paradigms for weather forecasting in southern Saskatchewan, Canada. The proposed ensemble method for weather forecasting has advantages over other techniques like linear combination. Generally, the output of an ensemble is a weighted sum, which are weight-fixed, with the weights being determined from the training or validation data. In the proposed approach, weights are determined dynamically from the respective certainties of the network outputs. The more certain a network seems to be of its decision, the higher the weight. The proposed ensemble model performance is contrasted with multi-layered perceptron network (MLPN), Elman recurrent neural network (ERNN), radial basis function network (RBFN), Hopfield model (HFM) predictive models and regression techniques. The data of temperature, wind speed and relative humidity are used to train and test the different models. With each model, 24-h-ahead forecasts are made for the winter, spring, summer and fall seasons. Moreover, the performance and reliability of the seven models are then evaluated by a number of statistical measures. Among the direct approaches employed, empirical results indicate that HFM is relatively less accurate and RBFN is relatively more reliable for the weather forecasting problem. In comparison, the ensemble of neural networks produced the most accurate forecasts.
TL;DR: It is concluded that the chicken genome encodes only β-defensin sequences and that all mammalian defensins are evolved from a common β- defensin-like ancestor.
Abstract: Defensins comprise a large family of cationic antimicrobial peptides that are characterized by the presence of a conserved cysteine-rich defensin motif. Based on the spacing pattern of cysteines, these defensins are broadly divided into five groups, namely plant, invertebrate, α-, β-, and θ-defensins, with the last three groups being mostly found in mammalian species. However, the evolutionary relationships among these five groups of defensins remain controversial. Following a comprehensive screen, here we report that the chicken genome encodes a total of 13 different β-defensins but with no other groups of defensins being discovered. These chicken β-defensin genes, designated as Gallinacin 1–13, are clustered densely within a 86-Kb distance on the chromosome 3q3.5-q3.7. The deduced peptides vary from 63 to 104 amino acid residues in length sharing the characteristic defensin motif. Based on the tissue expression pattern, 13 β-defensin genes can be divided into two subgroups with Gallinacin 1–7 being predominantly expressed in bone marrow and the respiratory tract and the remaining genes being restricted to liver and the urogenital tract. Comparative analysis of the defensin clusters among chicken, mouse, and human suggested that vertebrate defensins have evolved from a single β-defensin-like gene, which has undergone rapid duplication, diversification, and translocation in various vertebrate lineages during evolution. We conclude that the chicken genome encodes only β-defensin sequences and that all mammalian defensins are evolved from a common β-defensin-like ancestor. The α-defensins arose from β-defensins by gene duplication, which may have occurred after the divergence of mammals from other vertebrates, and θ-defensins have arisen from α-defensins specific to the primate lineage. Further analysis of these defensins in different vertebrate lineages will shed light on the mechanisms of host defense and evolution of innate immunity.
TL;DR: In this article, the authors present a review of the literature on non-market valuation of urban wetlands, with a particular focus on the value of urban wetland ecosystems, showing that certain types of wetlands or certain services are more highly valued than others.
Abstract: Wetlands provide a range of valuable ecosystem services from water purification and nutrient retention to recreation and aesthetics. The value of these services is often difficult to quantify and document to policy makers and the general public. Economists have developed non-market approaches to address difficult issues related to valuation of the environment. This paper reviews recent literature on non-market valuation as applied to wetlands, with a particular focus on the value of urban wetlands. Wetland valuation studies have generated a wide range of values, in part due to differences in what is valued and in part due to differences in methodology. Several studies have shown that property owners value proximity to wetlands in urban areas. In addition, studies have found positive values for recreation (fishing and hunting), commercial fishing, water purification, and other ecosystem services provided by wetlands, although little of this work has been done on urban wetlands. Valuation studies can provide useful information about relative rankings of value, showing, for example, that certain types of wetlands or certain services are more highly valued than others. Whether the absolute magnitude of valuation estimates is correct is less clear.
TL;DR: Using coordinated observations from instruments on the Advanced Composition Explorer (ACE), the Solar and Heliospheric Observatory (SOHO), and the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), this article evaluated the energetics of two well-observed flare/CME events on 21 April 2002 and 23 July 2002.
Abstract: Using coordinated observations from instruments on the Advanced Composition Explorer (ACE), the Solar and Heliospheric Observatory (SOHO), and the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), we have evaluated the energetics of two well-observed flare/CME events on 21 April 2002 and 23 July 2002. For each event, we have estimated the energy contents (and the likely uncertainties) of (1) the coronal mass ejection, (2) the thermal plasma at the Sun, (3) the hard X-ray producing accelerated electrons, (4) the gamma-ray producing ions, and (5) the solar energetic particles. The results are assimilated and discussed relative to the probable amount of nonpotential magnetic energy available in a large active region.
TL;DR: The A. marginale/vector/host studies described herein could serve as a model for research on other tick-borne rickettsiae and prospects for development of control strategies by use of pathogen and tick-derived antigens are discussed.
Abstract: The tick-borne intracellular pathogen Anaplasma marginale (Rickettsiales: Anaplasmataceae) develops persistent infections in cattle and tick hosts While erythrocytes appear to be the only site of infection in cattle, A marginale undergoes a complex developmental cycle in ticks and transmission occurs via salivary glands during feeding Many geographic isolates occur that vary in genotype, antigenic composition, morphology and infectivity for ticks In this chapter we review recent research on the host-vector-pathogen interactions of A marginale Major surface proteins (MSPs) play a crucial role in the interaction of A marginale with host cells The MSP1a protein, which is an adhesin for bovine erythrocytes and tick cells, is differentially regulated and affects infection and transmission of A marginale by Dermacentor spp ticks MSP2 undergoes antigenic variation and selection in cattle and ticks, and contributes to the maintenance of persistent infections Phylogenetic studies of A marginale geographic isolates using msp4 and msp1alpha provide information about the biogeography and evolution of A marginale: msp1alpha genotypes evolve under positive selection pressure Isolates of A marginale are maintained by independent transmission events and a mechanism of infection exclusion in cattle and ticks allows for only the infection of one isolate per animal Prospects for development of control strategies by use of pathogen and tick-derived antigens are discussed The A marginale/vector/host studies described herein could serve as a model for research on other tick-borne rickettsiae
TL;DR: The demonstration of the fermentation of biomass‐generated producer gas to ethanol is the major focus of this article and several key findings following the introduction of producer gas included: the cells stopped growing but were still viable, ethanol was primarily produced once the cells stop growing, and cells began growing again if “clean” bottled gases were introduced following exposure to the producer gas.
Abstract: The development of low-cost, sustainable, and renewable energy sources has been a major focus since the 1970s. Fuel-grade ethanol is one energy source that has great potential for being generated from biomass. The demonstration of the fermentation of biomass-generated producer gas to ethanol is the major focus of this article in addition to assessing the effects of producer gas on the fermentation process. In this work, producer gas (primarily CO, CO(2), CH(4), H(2), and N(2)) was generated from switchgrass via gasification. The fluidized-bed gasifier generated gas with a composition of 56.8% N(2), 14.7% CO, 16.5% CO(2), 4.4% H(2), and 4.2% CH(4). The producer gas was utilized in a 4-L bioreactor to generate ethanol and other products via fermentation using a novel clostridial bacterium. The effects of biomass-generated producer gas on cell concentration, hydrogen uptake, and acid/alcohol production are shown in comparison with "clean" bottled gases of similar compositions for CO, CO(2), and H(2). The successful implementation of generating producer gas from biomass and then fermenting the producer gas to ethanol was demonstrated. Several key findings following the introduction of producer gas included: (1) the cells stopped growing but were still viable, (2) ethanol was primarily produced once the cells stopped growing (ethanol is nongrowth associated), (3) H(2) utilization stopped, and (4) cells began growing again if "clean" bottled gases were introduced following exposure to the producer gas.
TL;DR: This article reviews the common themes that surfaced across work groups, with attention paid to the identification, training, and assessment of competencies and competence.
Abstract: The Competencies Conference: Future Directions in Education and Credentialing in Professional Psychology was organized around eight competency-focused work groups, as well as work groups on specialties and the assessment of competence. A diverse group of psychologists participated in this multisponsored conference. After describing the background and structure of the conference, this article reviews the common themes that surfaced across work groups, with attention paid to the identification, training, and assessment of competencies and competence. Recommendations to advance competency-based education, training, and credentialing in professional psychology are discussed. This is one of a series of articles published together in this issue of the Journal of Clinical Psychology. Several other articles that resulted from the Competencies Conference will appear in Professional Psychology: Research and Practice and The Counseling Psychologist.
TL;DR: Adaptation to carbon deprivation stress results in an increased tolerance to oxidative stress, which involves the induction of GSH-dependent elements of the antioxidant defence system.
Abstract: Glutathione (GSH; gamma-L-glutamyl-L-cysteinyl-glycine), a non-protein thiol with a very low redox potential (E'0 = 240 mV for thiol-disulfide exchange), is present in high concentration up to 10 mM in yeasts and filamentous fungi. GSH is concerned with basic cellular functions as well as the maintenance of mitochondrial structure, membrane integrity, and in cell differentiation and development. GSH plays key roles in the response to several stress situations in fungi. For example, GSH is an important antioxidant molecule, which reacts non-enzymatically with a series of reactive oxygen species. In addition, the response to oxidative stress also involves GSH biosynthesis enzymes, NADPH-dependent GSH-regenerating reductase, glutathione S-transferase along with peroxide-eliminating glutathione peroxidase and glutaredoxins. Some components of the GSH-dependent antioxidative defence system confer resistance against heat shock and osmotic stress. Formation of protein-SSG mixed disulfides results in protection against desiccation-induced oxidative injuries in lichens. Intracellular GSH and GSH-derived phytochelatins hinder the progression of heavy metal-initiated cell injuries by chelating and sequestering the metal ions themselves and/or by eliminating reactive oxygen species. In fungi, GSH is mobilized to ensure cellular maintenance under sulfur or nitrogen starvation. Moreover, adaptation to carbon deprivation stress results in an increased tolerance to oxidative stress, which involves the induction of GSH-dependent elements of the antioxidant defence system. GSH-dependent detoxification processes concern the elimination of toxic endogenous metabolites, such as excess formaldehyde produced during the growth of the methylotrophic yeasts, by formaldehyde dehydrogenase and methylglyoxal, a by-product of glycolysis, by the glyoxalase pathway. Detoxification of xenobiotics, such as halogenated aromatic and alkylating agents, relies on glutathione S-transferases. In yeast, these enzymes may participate in the elimination of toxic intermediates that accumulate in stationary phase and/or act in a similar fashion as heat shock proteins. GSH S-conjugates may also form in a glutathione S-transferases-independent way, e.g. through chemical reaction between GSH and the antifugal agent Thiram. GSH-dependent detoxification of penicillin side-chain precursors was shown in Penicillium sp. GSH controls aging and autolysis in several fungal species, and possesses an anti-apoptotic feature.
TL;DR: In this article, the authors describe course design elements most valued by adult learners in blended learning environments that combine face-to-face contact with Web-based learning and identify the online course features and the instructional design goals selected as most important by a sample of 67 adults and compares the group rankings with those of various subgroups based on gender, pre-course technology and self-direction skills and experiences, and preferred learning strategies as measured by Assessing the Learning Strategies of Adults (ATLAS).
Abstract: This research describes course design elements most valued by adult learners in blended learning environments that combine face‐to‐face contact with Web‐based learning. It identifies the online course features and the instructional design goals selected as most important by a sample of 67 adults and compares the group rankings with those of various sub‐groups based on gender, pre‐course technology and self‐direction skills and experiences, and preferred learning strategies as measured by Assessing the Learning Strategies of Adults (ATLAS). The results of the study support the principles of adult learning, indicating that adults value course designs containing options, personalization, self‐direction, variety, and a learning community. Findings also identify some differences in learning emphasis by gender, preferred learning strategies, and previous experience with technology and self‐directed learning. Implications of these findings for higher education in serving adult learners are discussed. Die von Erw...
TL;DR: New structural information, together with structures previously determined, provide a basis that, combined with biophysical and mutational data, suggest a modification to the existing classification of bc(1) inhibitors.
TL;DR: Although cytotype explained much of the variation among populations and the population x location interaction, ecotypic differentiation within cytotypes accounted for considerable variation in adaption of switchgrass populations.
Abstract: Switchgrass (Panicum virgatum L.) is a widely adapted warm-season perennial that has considerable potential as a biofuel crop. Evolutionary processes and environmental factors have combined to create considerable ecotypic differentiation in switchgrass. The objective of this study was to determine the nature of population × location interaction for switchgrass, quantifying potential differences in latitudinal adaptation of switchgrass populations. Twenty populations were evaluated for biofuel and agronomic traits for 2 yr at five locations ranging from 36 to 46° N lat. Biomass yield, survival, and plant height had considerable population × location interaction, much of which (53–65%) could be attributed to the linear effect of latitude and to germplasm groups (Northern Upland, Southern Upland, Northern Lowland, and Southern Lowland). Differences among populations were consistent across locations for maturity, dry matter, and lodging. Increasingly later maturity and the more rapid stem elongation rate of more southern-origin ecotypes (mainly lowland cytotypes) resulted in high biomass yield potential, reduced dry matter concentration, and longer retention of photosynthetically active tissue at more southern locations. Conversely, increasing cold tolerance of more northern-origin ecotypes (mainly upland cytotypes) resulted in higher survival, stand longevity, and sustained biomass yields at more northern locations, allowing switchgrass to thrive at cold, northern latitudes. Although cytotype explained much of the variation among populations and the population × location interaction, ecotypic differentiation within cytotypes accounted for considerable variation in adaption of switchgrass populations.
TL;DR: NdhR should be renamed ccmR to better represent its broader regulatory characteristics, indicating a vital role of this regulatory gene in both CO2 andbatchmode uptake.
TL;DR: The complex response of C. jejuni to iron availability is documents, the genetic network between the Fur and iron regulons is described, and insight is provided regarding the role of iron in C.Jejuni colonization in vivo.
Abstract: Iron affects the physiology of bacteria in two different ways: as a micronutrient for bacterial growth and as a catalyst for the formation of hydroxyl radicals. In this study, we used DNA microarrays to identify the C. jejuni genes that have their transcript abundance affected by iron availability. The transcript levels of 647 genes were affected after the addition of iron to iron-limited C. jejuni cells. Several classes of affected genes were revealed within 15 min, including immediate-early response genes as well as those specific to iron acquisition and metabolism. In contrast, only 208 genes were differentially expressed during steady-state experiments comparing iron-rich and iron-limited growth conditions. As expected, genes annotated as being involved in either iron acquisition or oxidative stress defense were downregulated during both time course and steady-state experiments, while genes encoding proteins involved in energy metabolism were upregulated. Because the level of protein glycosylation increased with iron limitation, iron may modulate the level of C. jejuni virulence by affecting the degree of protein glycosylation. Since iron homeostasis has been shown to be Fur regulated in C. jejuni, an isogenic fur mutant was used to define the Fur regulon by transcriptome profiling. A total of 53 genes were Fur regulated, including many genes not previously associated with Fur regulation. A putative Fur binding consensus sequence was identified in the promoter region of most iron-repressed and Fur-regulated genes. Interestingly, a fur mutant was found to be significantly affected in its ability to colonize the gastrointestinal tract of chicks, highlighting the importance of iron homeostasis in vivo. Directed mutagenesis of other genes identified by the microarray analyses allowed the characterization of the ferric enterobactin receptor, previously named CfrA. Chick colonization assays indicated that mutants defective in enterobactin-mediated iron acquisition were unable to colonize the gastrointestinal tract. In addition, a mutation in a receptor (Cj0178) for an uncharacterized iron source also resulted in reduced colonization potential. Overall, this work documents the complex response of C. jejuni to iron availability, describes the genetic network between the Fur and iron regulons, and provides insight regarding the role of iron in C. jejuni colonization in vivo.