Showing papers by "University of Arkansas published in 2003"

User acceptance of information technology: toward a unified view

Abstract: Information technology (IT) acceptance research has yielded many competing models, each with different sets of acceptance determinants. In this paper, we (1) review user acceptance literature and discuss eight prominent models, (2) empirically compare the eight models and their extensions, (3) formulate a unified model that integrates elements across the eight models, and (4) empirically validate the unified model. The eight models reviewed are the theory of reasoned action, the technology acceptance model, the motivational model, the theory of planned behavior, a model combining the technology acceptance model and the theory of planned behavior, the model of PC utilization, the innovation diffusion theory, and the social cognitive theory. Using data from four organizations over a six-month period with three points of measurement, the eight models explained between 17 percent and 53 percent of the variance in user intentions to use information technology. Next, a unified model, called the Unified Theory of Acceptance and Use of Technology (UTAUT), was formulated, with four core determinants of intention and usage, and up to four moderators of key relationships. UTAUT was then tested using the original data and found to outperform the eight individual models (adjusted R2 of 69 percent). UTAUT was then confirmed with data from two new organizations with similar results (adjusted R2 of 70 percent). UTAUT thus provides a useful tool for managers needing to assess the likelihood of success for new technology introductions and helps them understand the drivers of acceptance in order to proactively design interventions (including training, marketing, etc.) targeted at populations of users that may be less inclined to adopt and use new systems. The paper also makes several recommendations for future research including developing a deeper understanding of the dynamic influences studied here, refining measurement of the core constructs used in UTAUT, and understanding the organizational outcomes associated with new technology use.

User Acceptance of Information Technology: Toward a Unified View

Abstract: Information technology (IT) acceptance research has yielded many competing models, each with different sets of acceptance determinants. In this paper, we: (1) review user acceptance literature and discuss eight prominent models, (2) empirically compare the eight models and their extensions, (3) formulate a unified model that integrates elements across the eight models, and (4) empirically validate the unified model. The eight models reviewed are the theory of reasoned action, the technology acceptance model, the motivational model, the theory of planned behavior, a model combining the technology acceptance model and the theory of planned behavior, the model of PC utilization, the innovation diffusion theory, and the social cognitive theory. Using data from four organizations over a six-month period with three points of measurement, the eight models explained between 17 percent and 53 percent of the variance in user intentions to use information technology. Next, a unified model, called the Unified Theory of Acceptance and Use of Technology (UTAUT), was formulated, with four core determinants of intention and usage, and up to four moderators of key relationships. UTAUT was then tested using the original data and found to outperform the eight individual models (adjusted R2 of 69 percent). UTAUT was then confirmed with data from two new organizations with similar results (adjusted R2 of 70 percent). UTAUT thus provides a useful tool for managers needing to assess the likelihood of success for new technology introductions and helps them understand the drivers of acceptance in order to proactively design interventions (including training, marketing, etc.) targeted at populations of users that may be less inclined to adopt and use new systems. The paper also makes several recommendations for future research including developing a deeper understanding of the dynamic influences studied here, refining measurement of the core constructs used in UTAUT, and understanding the organizational outcomes associated with new technology use.

Experimental Determination of the Extinction Coefficient of CdTe, CdSe, and CdS Nanocrystals

Abstract: The extinction coefficient per mole of nanocrystals at the first exitonic absorption peak, e, for high-quality CdTe, CdSe, and CdS nanocrystals was found to be strongly dependent on the size of the nanocrystals, between a square and a cubic dependence. The measurements were carried out using either nanocrystals purified with monitored purification procedures or nanocrystals prepared through controlled etching methods. The nature of the surface ligands, the refractive index of the solvents, the PL quantum yield of the nanocrystals, the methods used for the synthesis of the nanocrystals, and the temperature for the measurements all did not show detectable influence on the extinction coefficient for a given sized nanocrystal within experimental error.

Criteria for the classification of monoclonal gammopathies, multiple myeloma and related disorders: a report of the International Myeloma Working Group

Abstract: The monoclonal gammopathies are a group of disorders associated with monoclonal proliferation of plasma cells. The characterization of specific entities is an area of difficulty in clinical practice. The International Myeloma Working Group has reviewed the criteria for diagnosis and classification with the aim of producing simple, easily used definitions based on routinely available investigations. In monoclonal gammopathy of undetermined significance (MGUS) or monoclonal gammopathy, unattributed/unassociated (MG[u]), the monoclonal protein is < 30 g/l and the bone marrow clonal cells < 10% with no evidence of multiple myeloma, other B-cell proliferative disorders or amyloidosis. In asymptomatic (smouldering) myeloma the M-protein is greater than or equal to 30 g/l and/or bone marrow clonal cells greater than or equal to 10% but no related organ or tissue impairment (ROTI)(end-organ damage), which is typically manifested by increased calcium, renal insufficiency, anaemia, or bone lesions (CRAB) attributed to the plasma cell proliferative process. Symptomatic myeloma requires evidence of ROTI. Non-secretory myeloma is characterized by the absence of an M-protein in the serum and urine, bone marrow plasmacytosis and ROTI. Solitary plasmacytoma of bone, extramedullary plasmacytoma and multiple solitary plasmacytomas (+/- recurrent) are also defined as distinct entities. The use of these criteria will facilitate comparison of therapeutic trial data. Evaluation of currently available prognostic factors may allow better definition of prognosis in multiple myeloma.

Large-scale synthesis of nearly monodisperse CdSe/CdS core/shell nanocrystals using air-stable reagents via successive ion layer adsorption and reaction.

Abstract: Successive ion layer adsorption and reaction (SILAR) originally developed for the deposition of thin films on solid substrates from solution baths is introduced as a technique for the growth of high-quality core/shell nanocrystals of compound semiconductors. The growth of the shell was designed to grow one monolayer at a time by alternating injections of air-stable and inexpensive cationic and anionic precursors into the reaction mixture with core nanocrystals. The principles of SILAR were demonstrated by the CdSe/CdS core/shell model system using its shell-thickness-dependent optical spectra as the probes with CdO and elemental S as the precursors. For this reaction system, a relatively high temperature, about 220−240 °C, was found to be essential for SILAR to fully occur. The synthesis can be readily performed on a multigram scale. The size distribution of the core/shell nanocrystals was maintained even after five monolayers of CdS shell (equivalent to about 10 times volume increase for a 3.5 nm CdSe na...

Disease Resistance and Abiotic Stress Tolerance in Rice Are Inversely Modulated by an Abscisic Acid–Inducible Mitogen-Activated Protein Kinase

Abstract: Mitogen-activated protein kinase (MAPK) cascades play an important role in mediating stress responses in eukaryotic organisms. However, little is known about the role of MAPKs in modulating the interaction of defense pathways activated by biotic and abiotic factors. In this study, we have isolated and functionally characterized a stress-responsive MAPK gene (OsMAPK5) from rice. OsMAPK5 is a single-copy gene but can generate at least two differentially spliced transcripts. The OsMAPK5 gene, its protein, and kinase activity were inducible by abscisic acid as well as various biotic (pathogen infection) and abiotic (wounding, drought, salt, and cold) stresses. To determine its biological function, we generated and analyzed transgenic rice plants with overexpression (using the 35S promoter of Cauliflower mosaic virus) or suppression (using double-stranded RNA interference [dsRNAi]) of OsMAPK5. Interestingly, suppression of OsMAPK5 expression and its kinase activity resulted in the constitutive expression of pathogenesis-related (PR) genes such as PR1 and PR10 in the dsRNAi transgenic plants and significantly enhanced resistance to fungal (Magnaporthe grisea) and bacterial (Burkholderia glumae) pathogens. However, these same dsRNAi lines had significant reductions in drought, salt, and cold tolerance. By contrast, overexpression lines exhibited increased OsMAPK5 kinase activity and increased tolerance to drought, salt, and cold stresses. These results strongly suggest that OsMAPK5 can positively regulate drought, salt, and cold tolerance and negatively modulate PR gene expression and broad-spectrum disease resistance.

Formation and stability of size-, shape-, and structure-controlled CdTe nanocrystals: Ligand effects on monomers and nanocrystals

Abstract: The formation of nearly monodisperse CdTe nanocrystalsdots (either zinc blende or wurtzite crystal structure), rods, and tetrapodsin a noncoordinating solvent was studied Several strong ligand effects were observed, and the ligand effects on the monomers were found to play a more important role than the ligand effects on the nanocrystals Experimental results suggest that, instead of monomer concentrations, monomer activities is a more relevant term for understanding the formation of nanocrystals because strong ligands always exist in the reaction solutions The bonding strength and the steric effects of ligands dramatically affect the reactivity of monomers and are considered as contributors to the activity coefficients of monomers The overall optical properties of the as-prepared CdTe nanocrystals are better than those reported in the literature and comparable to the standard CdSe nanocrystal system The configuration of the hydrocarbon chains of the ligands on the surface of each nanocrystal also pla

Making Healthful Food Choices: The Influence of Health Claims and Nutrition Information on Consumers’ Evaluations of Packaged Food Products and Restaurant Menu Items

Abstract: The authors report the results of three experiments that address the effects of health claims and nutrition information placed on restaurant menus and packaged food labels. The results indicate that when favorable nutrition information or health claims are presented, consumers have more favorable attitudes toward the product, nutrition attitudes, and purchase intentions, and they perceive risks of heart disease and stroke to be lower. The nutritional context in which a restaurant menu item is presented moderates the effects of both nutrition information and a health claim on consumer evaluations, which suggests that alternative (i.e., nontarget) menu items serve as a frame of reference against which the target menu item is evaluated.

The effects of psychological contract breach and organizational cynicism: not all social exchange violations are created equal

Abstract: This research explored the differential effects on employees of two types of social exchange violations: those that generate perceptions of psychological contract breach and of organizational cynicism. We predicted that psychological contract breach and cynicism would result in differential outcomes because of differences in the person specificity of their underlying social exchange relationships. Using a sample of bank employees, we found that cynicism partially mediated the effects of psychological contract breach on work-related attitudes (organizational commitment, job satisfaction), but that only psychological contract breach (not cynicism) predicted employees' behavioral responses (performance, absenteeism). Further, affective cynicism fully mediated the relationship between psychological contract breach and emotional exhaustion, suggesting that cynical attitudes have negative consequences for the attitude holder. Copyright © 2003 John Wiley & Sons, Ltd.

The Association between Audit Committee Characteristics and Audit Fees

Abstract: This study examines the association between audit committee characteristics and audit fees, using data gathered under the recent SEC fee disclosure rules. We hypothesize that audit fees will be positively associated with audit committee independence, financial expertise, and meeting frequency. We examine a sample of 492 nonregulated, Big 5‐audited firms that filed proxy statements with the SEC in the period from February 5, 2001 to June 30, 2001. We find that audit committee independence (defined as an audit committee comprised entirely of outside, independent directors) and financial expertise (defined as an audit committee containing at least one member with financial expertise) are significantly, positively associated with audit fees. This is in contrast to the findings of Carcello et al. (2002a), who find that audit committee characteristics are not significant in the presence of board‐related variables. Meeting frequency (defined as an audit committee that meets at least four times annually) was not ...

Developing and Validating an Observational Learning Model of Computer Software Training and Skill Acquisition

Abstract: Computer skills are key to organizational performance, and past research indicates that behavior modeling is a highly effective form of computer skill training. The present research develops and tests a new theoretical model of the underlyingobservational learning processes by which modeling-based training interventions influence computer task performance. Observational learning processes are represented as a second-order construct with four dimensions (attention, retention, production, and motivation). New measures for these dimensions were developed and shown to have strong psychometric properties. The proposed model controls for two pretraining individual differences (motivation to learn and self-efficacy) and specifies the relationships among three training outcomes (declarative knowledge, post-training self-efficacy, and task performance). The model was tested using PLS on data from an experiment ( N = 95) on computer spreadsheet training. As hypothesized, observational learning processes significantly influenced training outcomes. A representative modeling-based training intervention (retention enhancement) significantly improved task performance through its specific effects on the retention processes dimension of observational learning. The new model provides a more complete theoretical account of the mechanisms by which modeling-based interventions affect training outcomes, which should enable future research to systematically evaluate the effectiveness of a wide range of modeling-based training interventions. Further, the new instruments can be used by practitioners to refine ongoing training programs.

Single-Phase and Gram-Scale Routes toward Nearly Monodisperse Au and Other Noble Metal Nanocrystals

Abstract: Single-phase approaches are introduced for the synthesis of nearly monodisperse Au and other noble metal nanocrystals. The new approaches possess all the advantages of the popular Brust method. With weak ligands or surfactants for the metal ions, the control of the size and size distribution of the nanocrystals in synthesis in the size range between 1 and 15 nm was achieved via maintaining balanced nucleation and growth by tuning the activities of the metal precursors and reducing reagents. Because only weak ligands are employed in the new synthetic schemes, surface modification and functionalization of the resulting nanocrystals can be readily carried out.

The role of refugia for fishes during drought: a review and synthesis

Abstract: SUMMARY 1. Drought is a natural disturbance of aquatic ecosystems and can be a major factor in structuring aquatic communities. For individuals, populations and communities to persist in disturbed environments, they must have refuge from disturbance or disturbance must be minimal. Refugia convey spatial and temporal resistance or resilience in the face of disturbance, but the role of refugia in aquatic systems remains poorly understood. 2. We review available literature on aquatic refugia for fishes in order to synthesise current knowledge and provide suggestions for needed research. Our objectives were to clarify definitions of disturbance and refugia in the context of drought in aquatic systems, review how refuge habitats influence fish community structure, and consider the potential impact of refugia on fish population and community dynamics during drought. 3. Droughts cause a decrease in surface area/volume and an increase in extremes of physical and chemical water quality parameters. These conditions are linked with biotic interactions that structure the community of fishes residing in low-flow or dry season refugia by increasing mortality rates, decreasing birth rates and/or increasing migration rates. Many aquatic organisms seek refuge from disturbance and/or have adaptations (e.g. physiological tolerance) that provide refuge. 4. Drought in aquatic systems leads to shifts in refugia spacing and connectance at multiple spatial and temporal scales. Refuge size, disturbance intensity, and mobility of organisms is predicted to play a large role in population persistence. We expect that refuge habitats will experience net immigration during drying and net emigration after rewetting, with the opposite occurring in surrounding habitat patches. Population dynamics of fishes using refugia during drought are best modelled by modified source-sink dynamics, but dynamics are likely to change with spatial scale.

Surface-Related Emission in Highly Luminescent CdSe Quantum Dots

Abstract: We report our experimental studies of surface-related emission in highly luminescent CdSe quantum dots (QDs) with controlled quantum yield and photooxidation by time-resolved photoluminescence measurements. This kind of surface-related emission, with a radiative lifetime of tens of nanoseconds, implies the involvement of surface states in the carrier recombination process of such highly luminescent CdSe QDs.

Avoiding Pitfalls of Using Species-Distribution Models in Conservation Planning

Abstract: : Museum records have great potential to provide valuable insights into the vulnerability, historic distribution, and conservation of species, especially when coupled with species-distribution models used to predict species' ranges. Yet, the increasing dependence on species-distribution models in identifying conservation priorities calls for a more critical evaluation of model robustness. We used 11 bird species of conservation concern in Brazil's highly fragmented Atlantic Forest and data on environmental conditions in the region to predict species distributions. These predictions were repeated for five different model types for each of the 11 bird species. We then combined these species distributions for each model separately and applied a reserve-selection algorithm to identify priority sites. We compared the potential outcomes from the reserve selection among the models. Although similarity in identification of conservation reserve networks occurred among models, models differed markedly in geographic scope and flexibility of reserve networks. It is essential for planners to evaluate the conservation implications of false-positive and false-negative errors for their specific management scenario before beginning the modeling process. Reserve networks selected by models that minimized false-positive errors provided a better match with priority areas identified by specialists. Thus, we urge caution in the use of models that overestimate species' occurrences because they may misdirect conservation action. Our approach further demonstrates the great potential value of museum records to biodiversity studies and the utility of species-distribution models to conservation decision-making. Our results also demonstrate, however, that these models must be applied critically and cautiously. Resumen: Los registros de museos tienen un gran valor potencial al proporcionar entendimiento sobre la vulnerabilidad, distribucion historica y conservacion de especies, especialmente cuando se combinan con modelos de distribucion de especies utilizados para predecir los rangos de distribucion de las especies. No obstante, la mayor dependencia sobre los modelos de distribucion de especies para la identificacion de prioridades de conservacion requiere una evaluacion critica de la robustez del modelo. Utilizamos 11 especies de aves de interes para la conservacion en el muy fragmentado Bosque Atlantico en Brasil asi como datos de condiciones ambientales en la region para predecir la distribucion de las especies. Estas predicciones fueron repetidas para cinco tipos diferentes de modelos para cada una de las 11 especies de aves. Luego combinamos estas distribuciones de especies para cada modelo por separado y aplicamos un algoritmo de seleccion de reservas para identificar sitios prioritarios. Comparamos los resultados potenciales de la seleccion de reservas entre modelos. Aunque hubo similitud entre los modelos en la identificacion de redes de reservas, los modelos difirieron marcadamente en el alcance geografico y la flexibilidad de las redes de reservas. Es de importancia fundamental para los planificadores evaluar las implicaciones sobre la conservacion de errores falsos positivos y falsos negativos para su escenario de manejo especifico antes de comenzar el proceso de modelado. Las redes de reservas seleccionadas por modelos que minimizaron los errores falsos positivos proporcionaron mejor correspondencia con las areas prioritarias identificadas por especialistas. Por lo tanto, instamos a tener precaucion con el uso de modelos que sobreestiman la ocurrencia de especies porque pueden desviar las acciones de conservacion. Nuestro metodo demuestra ademas el gran potencial de los registros de museos en estudios de biodiversidad y la utilidad de los modelos de distribucion de especies para la toma de decisiones de conservacion. Sin embargo, nuestros resultados demuestran que estos modelos deben ser aplicados critica y cuidadosamente.

Teacher–Student Relationships as Compensatory Resources for Aggressive Children

Abstract: This 2-year prospective investigation examined the association between the quality of teacher-student relationships and children's levels of aggression in a sample of 140 second- and third-grade aggressive children (M age = 8.18). Consistent with the proposed dual-risk compensatory hypothesis, positive teacher-student relationships were more beneficial for aggressive African American and Hispanic children than for aggressive Caucasian children. Data did not support a moderating effect of negative parent-child relationship quality on the association between supportive teacher-student relationships and aggression. Findings underscore the importance of recruiting and preparing teachers capable of establishing supportive relationships with aggressive African American and Hispanic children. Results also suggest the need for multiple reporters of relationship quality in future research.

Quantifying Turfgrass Color Using Digital Image Analysis

Abstract: Color is a major component of the aesthetic quality of turf and often evaluated in field studies. Digital image analysis may be an improved, objective method to quantify turf color. Studies were conducted to determine if digital image analysis with SigmaScan software (SPSS, Chicago, IL) was capable of: (i) accurately determining the hue, saturation, and brightness (HSB) levels of Munsell Plant Tissue color chips, (ii) quantifying visual color differences among zoysiagrass (Zoysia japonica Steud.) and creeping bentgrass (Agrostis palustris Huds. { = A. stolonifera var. palustris (Hods.) Farw.}} plots receiving various N treatments, and (iii) quantifying genetic color differences among bermudagrass (Cynodon spp.) cultivars. Digital images of turf plots were analyzed with SigmaScan software to determine average HSB levels for each image. A dark green color index (DGCI) was created from HSB values for direct comparison with visual ratings. Digital image analysis accurately quantified the HSB levels (r 2 = 0.99, 0.96, and 0.97, respectively) of Munsell color chips corresponding to turf colors. Significant HSB differences were present among N treatments in creeping bentgrass, while only significant hue differences existed in zoysiagrass. Significant hue and saturation differences were present among bermudagrass cultivars. There was strong agreement between DGCI values and visual ratings. The relative variances of the HSB and DGCI were significantly less than the variance associated with multiple raters. This evaluation technique may facilitate objective comparisons of turf color across researchers, locations, and years when images are collected under equal lighting conditions (i.e., the use of an artificial light source at night or in an enclosed system).

Effects of solvent and temperature on pressurized liquid extraction of anthocyanins and total phenolics from dried red grape skin.

Abstract: Pressurized liquid extraction (PLE) was used to extract anthocyanins from the freeze-dried skin of a highly pigmented red wine grape with six solvents at 50 °C, 10.1 MPa, and 3 × 5 min extraction cycles. Temperature (from 20 to 140 °C in 20 °C increments) effects on anthocyanin recovery by acidified water and acidified 60% methanol were also studied. Acidified methanol extracted the highest levels of total monoglucosides and total anthocyanins, whereas the solvent mixture (40:40:20:0.1 methanol/acetone/water HCl) extracted the highest levels of total phenolics and total acylated anthocyanins. Acidified water extracts obtained by PLE at 80−100 °C had the highest levels of total monoglucosides, total acylated anthocyanins, total anthocyanins, total phenolics, and ORAC values. Acidified methanol extracts obtained by PLE at 60 °C had the highest levels of total monoglucosides and total anthocyanins, whereas extracts obtained at 120 °C had the highest levels of total phenolics. High-temperature PLE (80−100 °C)...

Luminescent CdSe/CdS core/shell nanocrystals in dendron boxes: superior chemical, photochemical and thermal stability.

Abstract: The surface ligands, generation-3 (G3) dendrons, on each semiconductor nanocrystal were globally cross-linked through ring-closing metathesis (RCM). The global cross-linking of the dendron ligands sealed each nanocrystal in a dendron box, which yielded box-nanocrystals. Although the dendron ligands coated CdSe nanocrystals (CdSe dendron-nanocrystals) were already quite stable, the stability of CdSe box-nanocrystals against chemical, photochemical, and thermal treatments were dramatically improved in comparison to that of the original dendron-nanocrystals. Furthermore, the box structure of the ligands monolayer coupled with the stable inorganic CdSe/CdS core/shell nanocrystals resulted in a class of extremely stable nanocrystal/ligands complexes. The band edge photoluminescence of the core/shell dendron-nanocrystals and box-nanocrystals were partially remained, and could be further brightened through controlled chemical oxidation or photooxidation. Practically, the stability of the box-nanocrystals is sufficient for most fundamental studies and technical applications. The box-nanocrystals may represent a general solution for the commonly encountered instability for many types of colloidal nanocrystals. The size distribution of the empty dendron boxes formed by the dissolution of the inorganic nanocrystals in concentrated HCl was very narrow. The empty boxes as new types of polymer capsules are soluble in solution, mesoporous, and with a very thin but stable peripheral. Those nanometer-sized cavities should be of interest for many purposes in the field of solution host-guest chemistry.

Enhanced pesticide sorption by soils containing particulate matter from crop residue burns.

Abstract: Lack of proper techniques to isolate black carbon (BC) from soils has hindered the understanding of their roles in the sorption and environmental fate of organic contaminants in soils and sediments. The burning of crop residues may be the primary source of BC in agricultural soils. In this study, wheat (Triticum aestivum L.) and rice (Oryza sativa L.) residues were burned, and the resulting particulate matter (ashes) along with a soil were used to sorb diuron from water. Calculations indicated that the burning of crop residues may result in an appreciable level of ashes in soils. The diuron sorption isotherms on ashes were curvilinear Langmuir type, suggestive of surface adsorption and similar to that with activated carbon. Ashes were 400-2500 times more effective than soil in sorbing diuron over the concentration range of 0-6 mg/L. Sorption by wheat ash-amended soils and the degree of isotherm nonlinearity increased with increasing ash content from 0% to 1% (weight), indicating the significant contribution of wheat ash to the sorption. Calculations show that wheat ash and soil independently contributed to the sorption. Above the wheat ash content of 0.05%, the sorption was largely controlled by the ash. Density-based fractionation and repeated HCI-HF washing of wheat ash yielded carbon-enriched fractions and enhanced diuron sorption by these fractions. BC appeared primarily responsible for the high adsorptivity of ashes. Ashes arising from the burning of crop residues may be an important determinant of pesticide immobilization and environmental fate in soils.

Antioxidant capacity and phenolic content in blueberries as affected by genotype and growing season

Abstract: Blueberry fruits from five commercial cultivars and 13 breeding selections grown at the same locations over two growing seasons were analysed for total phenolics (TPH), total anthocyanins (ACY), total hydroxycinnamic acids (HCA), total flavonols (FLA), fruit weight and oxygen radical-absorbing capacity (ORAC). Variation in ORAC, TPH, ACY, HCA, FLA and fruit weight among genotypes was much greater than that observed between growing seasons, indicating that genetics plays a more important role than growing season in influencing ORAC and phenolic content in blueberries. Significant main effects for growing season and genotype × growing season observed for ORAC, ACY, HCA and fruit weight demonstrate that environmental growing conditions can impact levels of phenolics and ORAC in blueberries and that certain genotypes vary in their capacity to synthesise phenolics under different growing conditions. In general, genotypes with smaller berries had higher ORAC values and levels of TPH, ACY, HCA and FLA than large-berried genotypes. Over both growing seasons, ORAC correlated highly with TPH, ACY, HCA and FLA, while fruit weight correlated inversely with all phenolics measured. Our results indicate that blueberry genotypes should be screened over multiple growing seasons in order to identify antioxidant- and phenolic-rich germplasm. Copyright © 2003 Society of Chemical Industry

Characterization of diversity in Colletotrichum acutatum sensu lato by sequence analysis of two gene introns, mtDNA and intron RFLPs, and mating compatibility

Abstract: A diverse collection of isolates identified as Colletotrichum acutatum, including a range of fruit-rot and foliar pathogens, was examined for mtDNA RFLPs and RFLPs and sequence variation of a 900-bp intron of the glutamine synthetase (GS) gene and a 200-bp intron of the glyceraldehyde-3-phosphate dehydrogenase (GPDH) gene. RFLPs of mtDNA, RFLPs of the 900-bp GS intron and sequence analysis of each intron identified the same seven distinct molecular groups, or clades, within C. acutatum sensu lato. Sequence analysis produced highly concordant tree topologies with definitive phylogenetic relationships within and between the clades. The clades might represent phylogenetically distinct species within C. acutatum sensu lato. Mating tests also were conducted to assess sexual compatibility with tester isolates known to outcross to form the teleomorph Glomerella acutata. Mating compatibility was identified within one clade, C, and between two phylogenetically distinct clades, C and J4. The C clade represented isolates from a wide range of hosts and geographic origins. J4 clade contained isolates from Australia or New Zealand recovered from fruit rot and pine seedlings with terminal crook disease. That isolates in two phylogenetically distinct clades were capable of mating suggests that genetic isolation occurred before reproductive isolation. No other isolates were sexually compatible with the mating testers, which also were in groups C and J4. Certain clades identified by mtDNA and intron analysis (D1, J3 and J6) appeared to represent relatively host-limited populations. Other clades (C1, F1 and J4) contained isolates from a wide range of hosts. Isolates described as C. acutatum f. sp. pineum were clearly polyphyletic.

An Empirical Investigation of Audit Fees, Nonaudit Fees, and Audit Committees*

Abstract: This stody examines the association between audit committee characteristics and the ratioof nonaudit service (NAS) fees to audit fees, using data gathered under the Secuiities andExchange Commission's (SEC's) fee disclosure rules. Issues related to NAS fees have beenof concern to practitioners, regulators, and academics for a number of years. Prior researchsuggests that audit committees possessing certain characteristics are important participantsin the process of managing the client—auditor relationship. We hypothesize that audit com-mittees that are independent and active financial monitors have incentives to limit NAS fees(relative to audit fees) paid to incumbent auditors, in an effort to enhance auditor indepen-dence in either appearance or fact. Our analysis using a sample of 538 flrms indicates thataudit committees comprised solely of independent directors meeting at least four timesamiually are significantly and negatively associated with the NAS fee ratio. This evidence isconsistent with audit committee members perceiving a high level of NAS fees in a negativelight and taking actions to decrease the NAS fee ratio.Keywords Audit committee; Audit fees; Auditor independence; Nonaudit seiYicesCoiidenseLes auteurs examinent le lien entre les caracteristiques du comite de verification et le rapportentre les honoraires des services autres que la verification (designes NAS — non-auditsenAces) et les honoraires des services de verification, a l'aide de donnees recueillies auxEtats-Unis, sous le regime des regies imposees par la Securities and Exchange Commission(SEC) en matiere d'ioformation a foumir sur les honoraires. Depuis bon nombre d'annees,les questions relatives aux honoraires des NAS preoccupent les praticiens, les responsablesde !a reglementation et ies chercheurs. La presente etude est motivee par deux decisions

Detection of Urban-Induced Rainfall Anomalies in a Major Coastal City

Abstract: There is increasing evidence that large coastal cities, like Houston, Texas, can influence weather through complex urban land use- weather-climate feedbacks. Recent work in the literature establishes the ex- istence of enhanced lightning activity over and downwind of Houston. Since lightning is a signature of convection in the atmosphere, it would seem rea- sonable that urbanized Houston would also impact the distribution of rainfall. This paper presents results using data from the world's first satellite-based precipitation radar (PR) aboard the Tropical Rainfall Measuring Mission (TRMM) and ground-based rain gauges to quantify rainfall anomalies that we hypothesize to be linked to extensive urbanization in the Houston area. It is one of the first rigorous efforts to quantify an urban-induced rainfall anomaly near a major U.S. coastal city and one of the first applications of space-borne radar data to the problem. Quantitative results reveal the presence of annual and warm season rainfall anomalies over and downwind of Houston. Several hypotheses have surfaced to explain how the sea breeze, coastline curvature,

Photoactivated CdSe Nanocrystals as Nanosensors for Gases

Abstract: The photoluminescence (PL) of high-quality CdSe nanocrystals (NCs) incorporated into polymer thin films was found to respond reversibly and rapidly to environmental changes upon photoradiation above their absorption onset. The PL of the NCs may be dramatically enhanced or diminished depending on the properties of the gases. Photostimulation was found to be necessary for the response, which likely makes the original dense-ligands monolayer on the surface of the NCs permeable to gases by the activation of the vibration modes of the NC lattice through photon−phonon coupling.

Early revascularization is associated with improved survival in elderly patients with acute myocardial infarction complicated by cardiogenic shock: a report from the SHOCK Trial Registry

Abstract: Aims The SHould we emergently revascularize Occluded Coronaries in cardiogenic shocK (SHOCK) Trial showed no benefit of early revascularization in patients aged ≥75 years with acute myocardial infarction and cardiogenic shock. We examined the effect of age on treatment and outcomes of patients with cardiogenic shock in the SHOCK Trial Registry. Methods and results We compared clinical and treatment factors in patients in the SHOCK Trial Registry with shock due to pump failure aged <75 years \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \((n=588)\) \end{document} and ≥75 years \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \((n=277)\) \end{document}, and 30-day mortality of patients treated with early revascularization <18 hours since onset of shock and those undergoing a later or no revascularization procedure. After excluding early deaths covariate-adjusted relative risk and 95% confidence intervals were calculated to compare the revascularization strategies within the two age groups. Older patients more often had prior myocardial infarction, congestive heart failure, renal insufficiency, other comorbidities, and severe coronary anatomy. In-hospital mortality in the early vs. late or no revascularization groups was 45 vs. 61% for patients aged <75 years \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \((p=0.002)\) \end{document} and 48 vs. 81% for those aged ≥75 years \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \((p=0.0003)\) \end{document}. After exclusion of 65 early deaths and covariate adjustment, the relative risk was 0.76 (0.59, 0.99; \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(p=0.045\) \end{document}) in patients aged <75 years and 0.46 (0.28, 0.75; \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(p=0.002\) \end{document}) in patients aged ≥75 years. Conclusions Elderly patients with myocardial infarction complicated by cardiogenic shock are less likely to be treated with invasive therapies than younger patients with shock. Covariate-adjusted modeling reveals that elderly patients selected for early revascularization have a lower mortality rate than those receiving a revascularization procedure later or never.

Comparing DC-DC converters for power management in hybrid electric vehicles

Abstract: The design of DC-DC converters for power electronic interfaces in power management systems for hybrid electric vehicle (HEV) is a very challenging task. To this end, this paper presents an analysis, design, and comparison study of several bi-directional non-isolated DC-DC converter topologies that could be considered potential candidates for the power electronic interface of HEV energy/power sources, in particular an ultracapacitor pack. The considered topologies are the half-bridge, Cuk, SEPIC, and Luo converters. The analysis and design of the converters is performed throughout equations for the stresses of the active and passive components. The comparison study, achieved by means of graphs where the variables of interest are plotted as a function of the voltage ratio Vo/Vi, uses the half-bridge converter as the base case. Particular attention is paid to the stresses of the active and passive components due to the wide input voltage requirements typical of this load-leveling or power-management application.