Showing papers by "University of Arkansas published in 1993"

Service firms' international entry-mode choice: A modified transaction-cost analysis approach

Abstract: Some peculiar characteristics of service firms, such as low capital intensity and the inseparability of production and consumption, have necessitated the modification of the traditional transaction...

Fit, Equifinality, and Organizational Effectiveness: A Test of Two Configurational Theories

Abstract: Mintzberg's and Miles and Snow's configurational theories have both received widespread attention. Most researchers, however, have interpreted these theories in terms of categories of organizations rather than organizational configurations based on ideal types. We explicated the logical structure of configurational theories and developed a set of configurational fit models that are congruent with alternative assumptions of equifinality, which is the premise that multiple organizational forms are equally effective. Then the two theories were formalized with these models and tested empirically. Contrary to our expectations, the results do not support Mintzberg's theory that organizations will be more effective to the extent that they resemble his five ideal types. In contrast with these null results, configurational fit based on Miles and Snow's theory predicted 24 percent of the variance in overall organizational effectiveness.

Observation of self-trapping of an optical beam due to the photorefractive effect.

Abstract: Recently, a new type of spatial soliton has been predicted to be observable in a photorefractive crystal.1,2 For example, consider an input laser beam that is diverging because of diffraction as it passes through a photorefractive material. Interference between the beam’s spatial-frequency components can be considered to write photorefractive gratings on the crystal. These gratings, or spatial variations in the index of refraction, have one component that is in phase and another that is 90° out of phase with their parent intensity pattern.

Effects of stressful job demands and control on physiological and attitudinal outcomes in a hospital setting.

Abstract: We tested the job demands--job control model of stress with a group of 136 registered nurses. Significant interactions between subjective and objective measures of work load and a measure of perceived control predicting physiological and attitudinal outcomes indicated support for the model. In addition, objectively assessed job demands were significantly associated with blood pressure and cortisol levels. The model also predicted elevations in physiological responses after individuals left work, suggesting that potentially health-impairing reactions to jobs that have high demands and low controllability might carry over to home settings and thus pose a high risk of long-term health impairment. The results have implications for the role of personal control in occupational stress generally and for nurse-management practices specifically.

Comparison of the boys and Pipek-Mezey localizations in the local correlation approach and automatic virtual basis selection

Abstract: Our implementation of Pipek-Mezey population localization is described. It is compared with other localization schemes and its use in the framework of the local correlation method is discussed. For such use, this localization is shown to be clearly superior to Boys in the case of physically well-localized systems. Our current algorithm for selection of local virtual spaces is also described

Effects of Poultry Litter Application Rate and Rainfall Intensity on Quality of Runoff from Fescuegrass Plots

Abstract: A 4×2 factorial experiment with three replications was conducted to determine how quality of runoff from grassed areas treated with poultry (Gallus gallus domesticus) litter is impacted by litter application rate and rainfall intensity for storms occurring 1 d after application. Poultry litter was applied at 0, 218, 435, and 870 kg N ha -1 to plots established with fescuegrass (Festuca arundinacea Schreb.) on a Captina silt loam soil (fine-silty, mixed, mesic Typic Fragiudult). Simulated rainfall was applied 24 h after litter application at 5 and 10 cm h -1 until runoff had occurred for a duration of 0.5 h.

Biological production of ethanol from coal synthesis gas

Abstract: The anaerobic bacteriaClostridium ljungdahlii produces ethanol and acetate from CO, CO2, and H2 in synthesis gas. Early studies with the bacterium showed that relatively high concentrations of ethanol could be produced by lowering the fermentation pH and eliminating yeast extract from the medium in favor of a defined medium. This article presents the results from a medium development study based on the aerobic bacteriumEscherichia coli. The results of continuous-reactor studies in a continuously stirred tank reactor (CSTR) with and without cell recycle are shown to demonstrate the utility of this improved medium.

Endophyte Effects on Growth and Persistence of Tall Fescue along a Water-Supply Gradient

Abstract: Ecophysiology of the endophyte (Acremonium coenophialum Morgan-Jones and Gams)-tall fescue (Festuca arundinacea Schreb.) association needs to be understood in order to promote environmental fitness traits of the association while reducing its deleterious effects on ruminants. Our objective was to determine the influence of endophyte on drought stress tolerance, persistence, and yield components of field-grown tall fescue on a Typic Hapludalfs soil. A water supply gradient was established during 1988 and 1989 with line-source irrigation on established populations of 0 and 80% endophyte-infected tall fescue. Whole plots consisted of endophyte infection status, across which a gradient of water was applied in a strip-split fashion with eight replicates [...]

Biduals of weighted banach spaces of analytic functions

Abstract: For a positive continuous weight function ν on an open subset G of CN, let Hv(G) and Hv0(G) denote the Banach spaces (under the weighted supremum norm) of all holomorphic functions f on G such that ν f is bounded and ν f vanishes at infinity, respectively. We address the biduality problem as to when Hν(G) is naturally isometrically isomorphic to Hν0(G)**, and show in particular that this is the case whenever the closed unit ball in Hν0(G) in compact-open dense in the closed unit ball of Hν(G).

How do L1 and L2 reading differ? Evidence from Think Aloud protocols

Abstract: "DISCIPLINES," AS HOBBS HAS WRITten, "are defined by what they consider given and what they take to be problematic" (p. 21). A crucial issue for investigators in the field of second/foreign language reading is whether the reading process is fundamentally different in the native language (Li) as opposed to the nonnative language (L2). In the research reported here, we used data collected from Think Aloud protocols to determine how two groups of adult subjects, who were proficient native language readers, approached reading in their L1 and in their L2. First, we briefly review some of the discussion about differences between Li and L2 reading. Second, we present the method, analytic techniques, and results of our study. Third, we suggest additional research questions raised by our findings. Finally, based upon results of this study of native readers of English and French, we propose that L2 reading researchers adopt a broader context within which to evalute the performance of subjects from cultures with diverging literacy practices.'

Consumer Perceptions of Tensile Price Claims in Advertisements: An Assessment of Claim Types Across Different Discount Levels:

Abstract: Findings are reported for two studies that examined the effects of three forms of tensile price claims (i.e., stating a minimum, maximum, or range of savings) on consumers’ price perceptions, search and shopping intentions, and estimates of price reduction across four different discount range levels. Hypotheses are offered based on a rationale drawn from an anchoring and adjustment framework. Results of both studies indicate that for broader discount ranges, tensile claims stating the maximum level of savings have more positive effects than those stating the minimum level or the entire savings range. For more narrow discount ranges, tensile claims stating the maximum level of savings appear to be no more effective than claims stating the minimum level or the entire savings range.

Spatial Patterns of Tree-Growth Anomalies in the United States and Southeastern Canada

Abstract: A network of 248 tree-ring chronologies in the conterminous United States is assembled and analyzed by rotated principal components analysis (RPCA) to delineate “regions” of common tree-growth variation during the period 1705–1979. Spatial continuity of the tree-ring data is summarized by variogram analysis, and tree-ring data are gridded before RPCA to reduce effects of site clustering. Principal component drought information is evaluated by comparing PC scores and primary pattern coefficients with Palmer Drought Severity Index (PDSI) data from instrumental records. High PC pattern coefficients group geographically into regions coinciding roughly with nine drought regions delineated by RPCA of PDSI by other researchers. The drought signal as measured by the correlation between tree-ring PC scores and July PDSI, 1929–79, is strongest in the South and the interior West (r>0.7), and weakest in the Northeast and Pacific Northwest (r<0.16). A count of years with large negative PC scores in multiple r...

The Concept concept

Abstract: This paper describes the application of formal concept analysis to the representation of relationships among word senses. The word "concept" is used as an exemplary case for three different formal contexts and their concept lattices. Formal contexts comprise both objects and attributes, explicitly indicating which objects share which attributes and which attributes share which objects. This information is then used to identify the concept nodes (for which there may or may not be a word ['label']) and the relationships among the nodes which form the Concept lattice. >

Self-trapping of optical beams in photorefractive media

Abstract: We study the possibility of self-trapping of an optical beam in a photorefractive medium under the combined influence of diffraction and self-scattering (two-wave mixing) of its spatial frequency components. We investigate the spectrum of solutions for the resulting photorefractive spatial solitons and discuss their unique properties. Design considerations and material requirements for experimental realization of these solitons, together with specific examples, are given.

Genetic relationships among and selection for rice yield and yield components

Abstract: Genetic correlations provide useful information to plant breeders for developing selection schemes. Genetic correlations among yield and yield components (panicle number, panicle weight, panicle length, primary branches, and plant height) for U.S. southern long-grain rice (Oryza sativa L.) have not been reported. The objectives of this work were to estimate and use genetic correlations in developing selection methodologies in rice breeding programs (.)

Southern Oscillation extremes reconstructed from tree rings of the Sierra Madre Occidental and southern Great Plains

Abstract: The El Ninio-Southern Oscillation (ENSO) is correlated with climate and tree growth over northern Mexico and the southern Great Plains of the USA. Warm events favor moist-cool conditions from October through March (event years 0 and +1), and subsequent tree growth (year +1) in the region tends to be above average. The opposite climate and tree growth conditions prevail with less consistency during cold events. ENSO-sensitive tree-ring chronologies from this region were selected to develop two reconstructions of the Southern Oscillation index (SOI) back to 1699. For the first reconstruction, a multiple regression-based calibration equation between prewhitened and regionally averaged tree-ring data from Mexico and Oklahoma and a prewhitened winter (DJF) SO index during the period 1900–71 were used to estimate the winter SOI for each year from 1699 to 1971. The tree-ring predictors account for 41% of the winter SOI variance from 1900 to 1971, and the reconstructed SO indices are significantly correl...

Choline acetyltransferase in schizophrenia

Abstract: Objective To test the hypothesis that schizophrenia involves altered cholinergic tone in the pons, the authors studied post-mortem brain tissue from subjects with schizophrenia. Method The authors used Western immunoblot to measure the concentration of choline acetyltransferase, an acetylcholine synthesizing enzyme, in the post-mortem brain tissue of 25 schizophrenic subjects and 28 nonschizophrenic comparison subjects. They also measured the concentration of glial fibrillary acidic protein, a protein from astrocytes, to examine the question of neurodegeneration. Results The pontine choline acetyltransferase concentrations of the schizophrenic subjects were 46% lower than those of comparison subjects, a significant difference. Glial fibrillary acidic protein concentrations did not differ between the two groups. Conclusions The lower concentration of choline acetyltransferase in the pontine tegmentum of schizophrenic subjects compared with comparison subjects suggests involvement of pontine cholinergic neurons in schizophrenia.

Nodular fasciitis: spontaneous resolution following diagnosis by fine-needle aspiration

Abstract: Nodular fasciitis can be histologically mistaken for a sarcoma. Typical cases are less than 5 cm and enlarge rapidly over days or weeks before diagnosis. The natural history of nodular fasciitis is unknown, since the diagnosis is usually based on excised lesions. Fine-needle aspiration of nodular fasciitis has been described, and features benign-appearing spindle cells (singly and in groups), collagen, and myxoid material. We describe 11 cases in which nonsurgical observation led spontaneously to complete resolution. Our study includes 7 males and 4 females (24 to 73 years of age; median = 42). Lesions were located in the arm (4), thigh (3), temporal area (2), breast (1) and the parotid (1) and ranged from 0.5 to 5.0 cm. (median = 1.5). They had been present for from less than 1 to 4 weeks (median = 2). In 9 cases, spontaneous resolution occurred in from 3 to 8 weeks (median = 4). Two other patients were lost to follow-up for up to 11 months, after which resolution was noted. Small palpable masses in the subcutaneous soft tissues which evolve over a short period of time and show the cytologic features of nodular fasciitis should be managed nonsurgically. If resolution does not occur within a few weeks, surgery can then be performed.

Nocturnality in Colonial Waterbirds: Occurrence, Special Adaptations, and Suspected Benefits

Abstract: Nocturnality, the habit of being active during darkness, has traditionally been viewed as characteristic of a minority of bird species, with the great majority being considered entirely diurnal. Primary examples of activity at night are found in the Apterigiformes, Strigiformes, Caprimulgiformes, and Apodiformes (Thomson, 1985; Martin, 1990). In the waterbirds (marine, freshwater, and marsh birds), excluding species that are crepuscular (i.e., active at dusk or dawn only), members of eight orders and 27 families are regularly or strictly active at night (Table I). Some seabirds are nocturnal in nest exchanges and chick feedings (e.g., storm petrels, shearwaters, diving petrels, small alcids) but to a large extent diurnal in their search for food. Many aquatic and wading birds (e.g., herons, ducks, shorebirds) are partly or mainly nocturnal, showing considerable activity by night, even during very dark nights. The Limpkins (Aramus aramus) and most rails and coots (Rallidae) are somewhat crepuscular or nocturnal; many species vocalize extensively at night (Bent, 1926; Van Tyne and Berger, 1976).

The prevalence of drugs and alcohol in fatally injured truck drivers.

Abstract: To assess the impact of alcohol and other drug use in the trucking industry, the National Transportation Safety Board, in collaboration with The National Institute on Drug Abuse investigated fatal-to-the-driver trucking accidents in eight states over a one year period. Comprehensive drug screens were performed on blood specimens collected from 168 fatally injured drivers. One or more drugs were detected in 67% of the drivers and 33% of the drivers had detectable blood concentrations of psychoactive drugs or alcohol. The most prevalent drugs were cannabinoids and ethanol, each found in 13% of the drivers. Cocaine or benzoylecgonine was found in 8% of the cases. Seven percent of the driver's blood specimens contained amphetamine or methamphetamine and 7% contained phenylpropanolamine, ephedrine, or pseudoephedrine. A panel of toxicologists reviewed the accident investigation report and the toxicology findings for each case and determined that impairment due to marijuana use was a factor in all cases where the delta-9-tetrahydrocannabinol concentration exceeded 1.0 ng/mL and that alcohol impairment contributed to all accidents where the blood alcohol concentration was 0.04% wt/vol or greater. In 50 of 56 cases where psychoactive drugs or alcohol were found, impairment due to substance use contributed to the fatal accident.

A Scale for Measuring Social Worker Empowerment

Abstract: This article describes the development of a 34-item scale designed to measure social workers' perceptions of personal and professional power. Utilizing selected methods of both rational and empirical scale construction approaches, the measure is derived from theory and statistically validated. The approach used a three-phase normalization procedure that employed multiple methods to extract items and enhance validity and reliability. Correlational and factor analysis were the primary statistical methods used in the validation process. A panel of 24 workers, a pilot sample of 62 professionals and students, and a random sample of 520 social workers were the participating respondent groups in this study. The final shortened scale is a relatively sound measure for tapping the five dimensions of empowerment.

Observer design for discrete and continuous non-linear stochastic systems

Abstract: An observer design methodology that is applicable to a general class of non-linear stochastic system and measurement models is given. It is proved that, under the conditions given, discrete- and continuous-time state estimation is possible with guaranteed exponential rate of convergence. The superior performance of the observer is illustrated with two examples.

Potential role of ascorbate oxidase as a plant defense protein against insect herbivory

Abstract: Ascorbic acid is essential for both nutritive and antioxidant functions in phytophagous insects; however, maintaining sufficient quantities of reduced ascorbate may be problematical for them. In this investigation, we show that the plant enzyme ascorbate oxidase retains activity in the digestive system of the herbivoreHelicoverpa zea. High levels of the enzyme are present in several host plants ofH. zea, including cotton, tomato, soybean, crimson clover, and vetch. The enzyme oxidizesL-ascorbic acid to dehydro-L-ascorbic acid, a potentially toxic product. The oxidation of ascorbic acid also produces active oxygen species such as the highly reactive hydroxyl radical. The nutritional quality of protein for larvalH. zea was significantly reduced by treatment with ascorbate and ascorbate oxidase. Oxidative damage to the protein was indicated by decreased lysine content, increased carbonyl formation, and the occurrence of protein fragmentation and polymerization. Furthermore, the oxidative loss of ascorbate in the herbivore's digestive system prevents ascorbate from functioning as an important antioxidant against a plethora of dietary prooxidants.

Chronic demands and responsivity to challenge.

Abstract: Certain kinds of arousal in response to challenge situations reflect conditioning that makes one adaptive to task demands. A growing literature implicates chronic stress as a factor degenerating this conditioning. This study investigated the relation between objective occupational demands to which workers were classified for at least 2 years and various indicators of adaptive responsivity to challenge situations. There were consistently significant and negative relations between the occupational exposures and cardiovascular and skin temperature responsivity to the acute challenges administered in the laboratory, the corresponding speed of recovery to baseline after removal of the challenge stimulus, and peripheral catecholamine changes during a work shift. Recent research using humans and animals as subjects indicates that chronic stress exposures may condition sympathetic nervous system arousal responses to demands in general. Specifically, there is evidence that chronic exposure to stressful conditions without corresponding control over coping resources may lead to a diminished ability to cope physiologically with challenging demands (see the review by Dienstbier, 1989). There are important implications if workers chronically exposed to occupational stress exhibit a lesser ability to respond adaptively to challenge situations. First, degeneration in responsivity can impede the worker's ability to perform effectively on challenging tasks, thereby reducing productivity and increasing workplace hazards. In addition, it has been suggested that diminished responsivity to challenge reduces the individual's capacity to cope actively with stressful demands (see Dienstbier, 1989). The degree of active coping in response to work-related stress is believed to determine whether the exposures will result in ill health (Karasek, Russell, & Theorell, 1982; Karasek et al., 1988). Such processes suggest an interactionist model wherein work environment exposures not only cause ill health, but also diminish adaptive physiological responses. Over time, stress exposures may become more toxic to individuals as their capacities for adaptation are reduced. Next, we review research suggesting that some forms of arousal are necessary for adaptation and that chronic stress can degenerate their activation in response to task challenges. We then present