Showing papers by "University of Arkansas published in 1989"
TL;DR: The results indicate that bacterial cells are capable of binding large quantities of different metals and Adsorption equations may be useful for describing bacterium-metal interactions with metals such as Cd and Cu; however, this approach may be adequate when precipitation of metals occurs.
Abstract: Four bacteria, Bacillus cereus, B. subtilis, Escherichia coli, and Pseudomonas aeruginosa, were examined for the ability to remove Ag+, Cd2+, Cu2+, and La3+ from solution by batch equilibration methods. Cd and Cu sorption over the concentration range 0.001 to 1 mM was described by Freundlich isotherms. At 1 mM concentrations of both Cd2+ and Cu2+, P. aeruginosa and B. cereus were the most and least efficient at metal removal, respectively. Freundlich K constants indicated that E. coli was most efficient at Cd2+ removal and B. subtilis removed the most Cu2+. Removal of Ag+ from solution by bacteria was very efficient; an average of 89% of the total Ag+ was removed from the 1 mM solution, while only 12, 29, and 27% of the total Cd2+, Cu2+, and La3+, respectively, were sorbed from 1 mM solutions. Electron microscopy indicated that La3+ accumulated at the cell surface as needlelike, crystalline precipitates. Silver precipitated as discrete colloidal aggregates at the cell surface and occasionally in the cytoplasm. Neither Cd2+ nor Cu2+ provided enough electron scattering to identify the location of sorption. The affinity series for bacterial removal of these metals decreased in the order Ag greater than La greater than Cu greater than Cd. The results indicate that bacterial cells are capable of binding large quantities of different metals. Adsorption equations may be useful for describing bacterium-metal interactions with metals such as Cd and Cu; however, this approach may not be adequate when precipitation of metals occurs.
496 citations
TL;DR: In this article, child witnesses to parental violence, both abused and nonabused, who were temporarily residing in a battered women's shelter were compared with children from a similar economic background (N =66) on measures of anxiety, depression, and behavior problems.
Abstract: Child witnesses to parental violence, both abused (N =40) and nonabused (N =44), who were temporarily residing in a battered women's shelter were compared with children from a similar economic background (N =66) on measures of anxiety, depression, and behavior problems. Mothers of the three groups of children (comparison, witness, abused/witness) across the age range from 4 to 12 years completed a behavior problem inventory; the youngsters responded to paper-and-pencil self-report measures. Results indicated that the abused/witness children were manifesting significantly more distress on the behavior problem measure than the comparison youngsters, with the witness children showing a moderate amount and the comparison children the least. However, these patterns were mediated by the age of the child. Implications of these differential findings are discussed.
313 citations
TL;DR: The Sexuality Scale as mentioned in this paper is an instrument designed to measure three aspects of human sexuality: sexualesteem, positive regard for and confidence in the capacity to experience one's sexuality in a satisfying and enjoyable way; sexualdepression, defined as the experience of feelings of depression regarding one's sex life; and sexual preoccupation, the tendency to think about sex to an excessive degree.
Abstract: This article describes the development of the Sexuality Scale, an instrument designed to measure three aspects of human sexuality: sexual‐esteem, defined as positive regard for and confidence in the capacity to experience one's sexuality in a satisfying and enjoyable way; sexual‐depression, defined as the experience of feelings of depression regarding one's sex life; and sexual‐preoccupation, defined as the tendency to think about sex to an excessive degree. The procedure involved (a) item construction, selection and subsequent validation through item analysis; and (b) a factor analysis of the items on the Sexuality Scale and the establishment of factorial validity. The results indicated that the three subscales were psychometrically sound, that males reported more sexual‐preoccupation than did females, and that the three subscales have unique intercorrelation patterns. The exploratory nature of these findings are discussed.
309 citations
TL;DR: The copper complex of histidine has been found to increase the secretion of luteinizing hormone-releasing hormone (LH-RH) from granules of the median eminence, consistent with the newly found role for copper in synthesis of neuroendocrine peptides.
Abstract: Publisher Summary This chapter discusses copper complexes that offer a physiological approach to the treatment of chronic diseases. Copper is recognized as an essential metalloelement just as sodium, potassium, magnesium, calcium, iron, zinc, chromium, vanadium, and manganese. Just as essential amino acids, essential fatty acids and essential cofactors (vitamins), essential metalloelements are required for normal metabolic processes but cannot be synthesized de novo, and daily dietary intake and absorption are required. The adult body contains between 1.4 mg (22 pmol) and 2.1 mg (33 pmol) of copper per kilogram of body weight while the infant body contains three times this amount, consistent with the fact that infant metabolic needs are that much greater than those of adults. The essentiality of copper is now understood as being based upon its recognized need for activation of copper-dependent enzymes. Complexed forms of copper also facilitate absorption, tissue distribution, and tissue utilization. In the nondisease state, these forms of copper account for the physiologic regulation of copper-dependent homeostatic processes. Consistent with the newly found role for copper in synthesis of neuroendocrine peptides, the copper complex of histidine has been found to increase the secretion of luteinizing hormone-releasing hormone (LH-RH) from granules of the median eminence.
309 citations
TL;DR: A partial cDNA clone isolated on the basis of its preferential hybridization to RNA from normal versus regenerating rat liver is described, resulting in a 53% decrease in the fraction of nuclei incorporating tritiated thymidine in human diploid fibroblasts.
167 citations
TL;DR: In this article, a culture has been isolated from animal waste that is capable of producing ethanol and acetate from carbon monoxide and from hydrogen and carbon dioxide, the major components of synthesis gas.
Abstract: There has been considerable interest recently in the production of liquid fuels from coal through direct or indirect liquefaction. A culture has been isolated from animal waste that is capable of producing ethanol and acetate from carbon monoxide and from hydrogen and carbon dioxide, the major components of synthesis gas. This paper presents results of batch and continuous laboratory studies with this culture. Special efforts are directed toward maximizing the ratio of ethanol to acetate.
156 citations
TL;DR: Canopy height and dry weight decreased linearly with duration of the flood at both growth stages, and growth rates were 25 to 35% less when soybean was flooded at R2 than at V4.
Abstract: (...)Flood duration effects on the soybean plant were manifested in yellowing and abscission of leaves at the lower nodes,stunting, and reduced dry weight and seed yield. Canopy height and dry weight decreased linearly with duration of the flood at both growth stages. The growth rates were 25 to 35% less when soybean was flooded at R2 than at V4. The additional 4 wk of vegetative growth after flooding allowed the soybean flooded at V4 to recover to a greater extent than the cultivars flooded at R2 (...)
148 citations
TL;DR: Some generalizations of binary template matching procedures which enable one to weight matches according to both statistical and spatial information are considered.
135 citations
TL;DR: In this article, a double step characteristic is observed at 76 K in the transport critical current as a function of magnetic field (10 -4 T to 10 T) in bulk sintered Y-, Bi-and Tl-based high-T c superconducting materials.
Abstract: A double step characteristic is observed at 76 K in the transport critical current as a function of magnetic field (10 -4 T to 10 T) in bulk sintered Y-, Bi- and Tl-based high- T c superconducting materials. The low-field, step-like drop in the critical current density J c commences at magnetic fields B between about 0.3 and 2 mT. This is followed by a plateau region of relatively constant critical current extending from about 30 to 300 mT, and then a second drop at fields between about 0.3 and 10 T. These features occur for all three superconductor materials and are interpreted respectively as a self-field/weak-link regime, a remnant percolation path regime and a flux-flow/upper-critical-field regime. The sharpness of the transition of the voltage-current ( V-I characteristic, represented by the transition parameter n (i.e., V ∝ I n ), has a similar double-step shape as a function of magnetic field directly corresponding to the features of the J c ( B ) characteristic.
132 citations
107 citations
TL;DR: In this paper, an econometric model pooling monthly cross-sectional and time-series data is estimated to measure the impact of national and regional generic fluid milk advertising, showing that the effectiveness of advertising has increased since the implementation of the Dairy Adjustment Act.
Abstract: An econometric model pooling monthly cross-sectional and time-series data is estimated to measure the impact of national and regional generic fluid milk advertising. The estimated model shows that the effectiveness of advertising has increased since the implementation of the Dairy Adjustment Act. Gains in fluid milk sales attributed to milk advertising are estimated. Sales gains for both the pre- and post-act periods are shown along with the gains associated with parameter changes in the post-act periods. Marginal advertising responses are derived.
TL;DR: A method for determining fermentation parameters of a gaseous substrate in convenient batch vessels using a modified Monod model is presented and experimental data for the conversion of carbon monoxide to acetate by the strict anaerobe Peptostreptococcus productus is illustrated.
Abstract: The fermentation of gaseous substrates such as CO, H2, and CO2 may be performed in a continuous stirred tank reactor, as well as the traditional batch reactor. In this article, the conversion of carbon monoxide by Peptostreptococcus productus is demonstrated in a stirred tank reactor under both mass transfer-controlled and nonmass transfer-controlled conditions. Utilizing a non-steady-state procedure, intrinsic rates are evaluated under non-mass transfer-controlled conditions in a time period of only 5–6 hours. A steady-state procedure was used to evaluate CSTR performance under mass transfer-controlled conditions. The mass transfer coefficient was calculated, followed by the development of a model to predict CSTR behavior for this gas phase substrate.
TL;DR: Cytochrome c derivatives labeled at specific lysine amino groups with ruthenium bis(bipyridine) dicarboxybipyrsidine [RuII(bpy)2(dcbpy)] were prepared by using the procedure described previously and have a strong luminescence emission centered at 662 nm arising from the excited state, RuII*.
Abstract: Cytochrome c derivatives labeled at specific lysine amino groups with ruthenium bis(bipyridine) dicarboxybipyridine [RuII(bpy)2(dcbpy)] were prepared by using the procedure described previously [Pan, L. P., Durham, B., Wolinska, J., & Millett, F. (1988) Biochemistry 27, 7180-7184]. Four additional singly labeled derivatives were purified, bringing the total number to 10. These derivatives have a strong luminescence emission centered at 662 nm arising from the excited state, RuII*. Transient absorption spectroscopy was used to directly measure the rate constants for the photoinduced electron-transfer reaction from RuII* to the ferric heme group (k1) and for the thermal back-reaction from the ferrous heme group to RuIII (k2). The rate constants were found to be k1 = 14 X 10(6) s-1 and k2 = 24 X 10(6) s-1 for the derivative modified at lysine 72, which has a distance of 8-16 A between the ruthenium and heme groups. Similar rate constants were found for the derivatives modified at lysines 13 and 27, which have distances of 6-12 A separating the ruthenium and heme groups. The rate constants were significantly slower for the derivatives modified at lysine 25 (k1 = 1 X 10(6) s-1, k2 = 1.5 X 10(6) s-1) and lysine 7 (k1 = 0.3 X 10(6) s-1, k2 = 0.5 X 10(6) s-1), which have distances of 9-16 A. Transients due to photoinduced electron transfer could not be detected for the remaining derivatives, which have larger distances between the ruthenium and heme groups.(ABSTRACT TRUNCATED AT 250 WORDS)
01 Jan 1989
TL;DR: In this article, the authors introduce two properties which are useful in addressing the question of non-uniqueness of representations of phase-type distributions, and discuss their interrelationship, and relate them to some known results on mixtures of convolutions of exponential distributions.
Abstract: We introduce two properties which are useful in addressing the question of non-uniqueness of representations of phase-type distributions. One property, called phase-type simplicity, concerns the possibility that a given phase-type distribution may have two distinct representations in terms of the same Markov chain. The second, called phase-type majorization, concerns the possibility that one Markov chain may provide representations for all the distributions represented by another Markov chain. We prove some characterizations of these properties, discuss their interrelationship, and relate them to some known results on mixtures of convolutions of exponential distributions.
TL;DR: In this paper, an analysis of the films Alien and Aliens reveals that the frontier myth is evolving, at least in this case, into a land/space hybrid, in which the lost feminine is encountered, found to be vengeful at the exploitation of her domain, and then killed by a patriarchalized heroine.
Abstract: Feminine symbolism in the American frontier myth is an evolving cultural/rhetorical manifestation of a developing archetypal process. The land‐based frontier myth represents a middle stage in which a once‐whole image of the feminine was split by the emergence of patriarchy. An analysis of the films Alien and Aliens reveals that the frontier myth is evolving, at least in this case, into a land/space hybrid, in which the lost feminine is encountered, found to be vengeful at the exploitation of her domain, and then killed by a patriarchalized heroine.
TL;DR: Cet article de synthese fait le point sur les mecanismes d'absorption des sels dans la branche grele ascendante de l'anse de Henle dans the corticale et the medullaire renale.
TL;DR: In this article, a two-level atom with the radiation field is studied when the radiation is initially in a strongly squeezed coherent state and the mean, variance, and entropy for the photon-number distribution are calculated and found to show behavior similar to that of the atomic inversion.
Abstract: The Jaynes–Cummings interaction of a two-level atom with the radiation field is studied when the radiation is initially in a strongly squeezed coherent state. The dynamic response of the atomic inversion shows echoes after each revival when the squeezed coherent state exhibits an oscillatory photon-counting distribution due to the phase-space interference effect. The sensitivity of the dynamic behavior to approximations used in computing the atomic inversion is discussed. Comparison is made with the intensity-dependent interaction model of Buck and Sukumar [ Phys. Lett.81A, 132 ( 1981)]; this model does not exhibit echoes. The mean, variance, and entropy for the photon-number distribution are calculated and found to show behavior similar to that of the atomic inversion.
TL;DR: Peptide mapping and sequencing studies revealed two sites of linkage between the two proteins, and Asp-44 of plastocyanin is covalently linked to Lys-187 of cytochrome f, which represents the first identification of a group on cy tochrome f that is involved in the interaction with plastOCyanin.
Abstract: Spinach plastocyanin and turnip cytochrome f have been covalently linked by using a water-soluble carbodiimide to yield an adduct of the two proteins. The redox potential of cytochrome f in the adduct was shifted by -20 mV relative to that of free cytochrome f, while the redox potential of plastocyanin in the adduct was the same as that of free plastocyanin. Solvent perturbation studies showed the degree of heme exposure in the adduct to be less than in free cytochrome f, indicating that plastocyanin was linked in such a way as to bury the exposed heme edge. Small changes were also observed when the resonance Raman spectrum of the adduct was compared to that of free cytochrome f. The adduct was incapable of interacting with or donating electrons to photosystem I. Peptide mapping and sequencing studies revealed two sites of linkage between the two proteins. In one site of linkage, Asp-44 of plastocyanin is covalently linked to Lys-187 of cytochrome f. This represents the first identification of a group on cytochrome f that is involved in the interaction with plastocyanin. The other site of linkage involves Glu-59 and/or Glu-60 of plastocyanin to as yet unidentified amino groups on cytochrome f. Euglena cytochrome c-552 could also be covalently linked to turnip cytochrome f, although with a lower efficiency than spinach plastocyanin. In contrast, a variety of cyanobacterial cytochrome c-553's and a cyanobacterial plastocyanin could not be covalently linked to turnip cytochrome f.
TL;DR: These experiments suggest that lysine 338 is located at the binding site for adrenodoxin and electrostatically interacts with one of the carboxylate groups on Adrenodoxin that has been implicated in binding.
TL;DR: In this paper, a study was conducted to determine the logical reasoning necessary to construct line graphs and the responses were classified into one of nine categories: no attempt to make a graph, complete graph with a statement of a relationship between the variables.
Abstract: A study was conducted to determine the logical reasoning necessary to construct line graphs. Three types of line graphs were used: a straight line with a positive slope, a straight line with a negative slope, and an exponentially increasing curve. The subjects were students in grades six through twelve enrolled in a laboratory school. The responses were classified into one of nine categories. The categories ranged from no attempt to make a graph to a complete graph with a statement of a relationship between the variables. Subjects in grades six through eight exhibited behaviors mainly in the first four categories, ninth- and tenth-grade subjects scored in the middle categories, and eleventh and twelfth graders scored mainly in the upper categories. These response categories also showed a close fit with Piagetian concrete operational structures for single and double seriation and formal operational structures for proportional reasoning and correlational reasoning.
TL;DR: The paper presents the results from ammonia limited batch and continuous fermentations using the yeast strain Saccharomycopsis (Candida) lipolytica (NRRL Y-7576), and cell and acid yields appeared to be almost the same inbatch and continuous culture.
Abstract: Citric acid is finding new areas of use each year and the demand for the acid is constantly increasing. Being a bulk chemical, the continuous production of citric acid would be advantageous. The paper presents the results from ammonia limited batch and continuous fermentations using the yeast strainSaccharomycopsis (Candida) lipolytica (NRRL Y-7576). Mathematical models were developed for growth and glucose utilization in batch and continuous culture. Cell and acid yields appeared to be almost the same in batch and continuous culture. The specific production rates were found to be constant, equal to 0.053 g/g h, in the batch fermentations but varied in the continuous experiments from 0 to 0.11 g/g h depending on the fermentation conditions. Continuous production in a single stage CSTR was studied for over 1,000 hours without shutdown.
TL;DR: Feeding trials indicate that the addition of a buffered propionic acid can alter intestinal microflora and decrease contamination of the processed carcass without adversely affecting live bird performance and processing trials indicate some chemicals at high concentrations may produce undesirable organoleptic characteristics.
TL;DR: In this paper, an evolving shadow myth that expresses repressed fears the culture has about its relationship to technology is constructed through an examination of Rocky IV, Blade Runner, and The Terminator.
Abstract: Through an examination of Rocky IV, Blade Runner, and The Terminator, this essay constructs an evolving dystopian shadow myth that expresses repressed fears the culture has about its relationship to technology. In its patriarchal form, the myth depicts an increasing division of technological agency from human agent, leading toward an entelechial end of human obsolescence. If this tragic “perfection” is to be averted, the myth implies, the culture must reintegrate feminine values into its consciousness, thereby activating an oppositional entelechial motive to reidentify agent with agency.
TL;DR: In this paper, the stability robustness problem for nominally stable linear discrete-time systems using time-domain analysis methods and Lyapunov theory is considered, and bounds on the norms of the time-varying (non-)linear perturbations are given, to maintain the asymptotic stability of these systems in the presence of such perturbation.
Abstract: The stability robustness problem is considered for nominally stable linear discrete-time systems Using time-domain analysis methods and Lyapunov theory, bounds on the norms of the time-varying (non-)linear perturbations are given, to maintain the asymptotic stability of these systems in the presence of such perturbations
TL;DR: Le pattern and the distance de dispersion de ces excrements sont determines pour estimer leur influence dans l'evitement de the predation.
Abstract: Etude de la predation sur le nid et de l'influence des excrements dans le reperage du predateur. Le pattern et la distance de dispersion de ces excrements sont determines pour estimer leur influence dans l'evitement de la predation
TL;DR: The lactoperoxidase-thiocyanate-H2O2 system delayed but did not prevent growth of L. monocytogenes Scott A and the net lag periods determined spectrophotometrically varied inversely with temperature and were shorter at 5 and 10 degrees C for cultures from shaken versus from statically grown inocula.
Abstract: The lactoperoxidase-thiocyanate-H2O2 system (LP system), consisting of lactoperoxidase (0.37 U/ml), KSCN (0.3 mM), and H2O2 (0.3 mM), delayed but did not prevent growth of L. monocytogenes Scott A at 5, 10, 20, and 30 degrees C in broth and at 20 degrees C in milk. The net lag periods determined spectrophotometrically varied inversely with temperature and were shorter at 5 and 10 degrees C for cultures from shaken versus from statically grown inocula. Lag periods for cultures from shaken and statically grown inocula, respectively, were 73 and 98 h at 5 degrees C, 22 and 32 h at 10 degrees C, both 8.9 h at 20 degrees C, and both 2.8 h at 30 degrees C. After the lag periods, the maximum specific growth rates were similar for each of the three treatments (complete LP system, H2O2 alone, or control broth) at 5, 10, and 20 degrees C and were 0.06 to 0.08, 0.09 to 0.1, and 0.32 to 0.36/h, respectively. At 20 degrees C in sterile reconstituted skim milk, the LP system restricted growth of Scott A, with log CFU counts per ml at 0, 36, and 68 h being 5.7, 6.4 and 7.9 (versus 5.7, 9.8, and 11.2 for controls). Possible explanations for the decreased lag times observed for cultures from aerobically grown inocula are discussed.
TL;DR: Tomato spotted wilt virus (TSWV) was obtained from infected tomatoes in commercial fields in Arkansas in 1985 and a greenhouse screening procedure for identifying tomatoes resistant to TSWV was established using an enzyme-linked immunosorbent assay (ELISA) to detect infected plants.
Abstract: Tomato spotted wilt virus (TSWV) was obtained from infected tomatoes in commercial fields in Arkansas in 1985. A greenhouse screening procedure for identifying tomatoes resistant to TSWV was established using an enzyme-linked immunosorbent assay (ELISA) to detect infected plants. Symptom expression was variable and symptom expression was not reliable for identifying infected plants. Germplasm evaluated for resistance to one typical Arkansas isolate (85–9) of TSWV included: twenty cultivars and breeding lines of Lycopersicon esculentum Mill, 52 accessions of L. pimpinellifolium (Jusl.) Mill and 8 accessions of L. peruvianum (L.) Mill. All cultivated accessions and breeding lines evaluated were susceptible. Some individual plants in several accessions of L. pimpinellifolium were resistant and nearly all plants of the L. peruvianum accessions that were evaluated were resistant to isolate 85–9.
TL;DR: The second Shuttle Imaging Radar experiment (SIR-B) obtained two digital images over the summit caldera and the Southwest Rift Zone of Kilauea Volcano in 1984 as discussed by the authors.
Abstract: Analyses of imaging radar data of volcanic terranes on Earth and Venus have emphasized the need for a clearer understanding of how these data can be most effectively used to accomplish important volcanological goals, including the interpretation of eruptive styles and the characterization of the geologic history of volcanic centers. The second Shuttle Imaging Radar experiment (SIR-B) obtained two digital images over the summit caldera and the Southwest Rift Zone of Kilauea Volcano in 1984. Our geologic analyses of these images indicate that SIR-B data are particularly useful for delineating the distribution and surface textural variations of a9a lava flows, for mapping large-scale topographic features with radar-facing slopes, and for identifying an areally extensive pyroclastic deposit. Analyses of the SIR-B data of Kilauea, however, do not permit unambiguous identification of landforms such as pahoehoe lava flows, cinder cones, and fissures. Although separation of low-return units such as pahoehoe lava flows and adjacent pyroclastic ash is not greatly improved using standard image-enhancement techniques, the texture-analysis technique applied here did facilitate discrimination of such smooth-surfaced volcanic deposits. Although analyses of the SIR-B data permit a generally accurate interpretation of the eruptive history of Kilauea, the inability to distinguish low-return pahoehoe flows results in misinterpretation of several aspects of Kilauea volcanism, suggesting that caution should be exercised in the interpretation of SAR data of volcanic terranes.
TL;DR: Phospholipid fatty acid composition analysis revealed that the normal rat fed the saturated fat or menhaden oil diet had significantly decreased arachidonate levels, consistent with decreased Δ5 desaturase activities and decreased 18∶2n−6 intake.
Abstract: We have studied the effect of various diets on the phospholipid fatty acid composition andin vitro Δ5 desaturase activity of hepatic microsomes derived either from the normal or streptozotocin-induced diabetic rat. The diets studied were the standard rat chow diet and a basal fat-free diet supplemented either with 20 percent saturated fat, 20 percent unsaturated fat, or 20 percent menhaden oil. Phospholipid fatty acid composition analysis revealed that the normal rat fed the saturated fat or menhaden oil diet had significantly decreased arachidonate levels, consistent with decreased Δ5 desaturase activities and decreased 18∶2n−6 intake. On the contrary, the unsaturated fat diet decreased dihomo-γ-linolenate and increased arachidonate levels, without increased Δ5 desaturase activity. Streptozotocininduced diabetes resulted in decreased arachidonate and Δ5 desaturase activity. The unsaturated fat diet fed to the diabetic rat also failed to correct this decreased Δ5 desaturase activity. The unsaturated fatty acids in this diet also displaced a substantial amount of n−3 fatty acids in both normal and diabetic microsomes, due to the competition between these two fatty acid families for incorporation into the membrane phospholipids. Conversely, the menhaden oil diet fed to the normal and diabetic rats displaced n−6 fatty acids, reduced Δ5 desaturase activity, and enhanced 22∶6n−3 incorporation into diabetic microsomes.