Showing papers by "Oklahoma State University–Stillwater published in 1997"
09 Jun 1997
TL;DR: The application of Bayesian regularization to the training of feedforward neural networks is described, using a Gauss-Newton approximation to the Hessian matrix to reduce the computational overhead.
Abstract: This paper describes the application of Bayesian regularization to the training of feedforward neural networks. A Gauss-Newton approximation to the Hessian matrix, which can be conveniently implemented within the framework of the Levenberg-Marquardt algorithm, is used to reduce the computational overhead. The resulting algorithm is demonstrated on a simple test problem and is then applied to three practical problems. The results demonstrate that the algorithm produces networks which have excellent generalization capabilities.
1,338 citations
TL;DR: In this paper, a local geometric realization of quantum field theories together with a local application of mirror symmetry is proposed to reduce non-trivial quantum field theory results to much better understood T -dualities of type 11 strings.
726 citations
TL;DR: In this article, the authors discuss how four contextual factors affect organizational receptivity to transformational leadership and how the configuration of these factors may be used as a framework for enriching transformational research.
Abstract: In the existing transformational leadership research, little attention has been paid to contextual influences on transformational leadership. To more fully understand transformational leadership as an organizational process, researchers must study it in relation to a contextual framework. We discuss how four contextual factors affect organizational receptivity to transformational leadership. We also examine how the configuration of these factors may be used as a framework for enriching transformational leadership research.
597 citations
TL;DR: Water loss is not unique to desert streams, because intermittent streams are found in many different environments and increasing demands on a finite water supply arc increasing the likelihood of drying in streams and rivers worldwide as discussed by the authors.
Abstract: St re
439 citations
TL;DR: The unidimensional nature of the Perceived Wellness Survey suggests that perceptions of wellness in various dimensions are intertwined by their affective nature.
Abstract: Purpose. The impact of individual perceptions on health is well-established. However, no valid and reliable measure of individual wellness perceptions exists. Therefore, the purpose was to introduce a measure called the Perceived Wellness Survey (PWS). Design. Convenience sampling facilitated recruitment of a sample large enough to perform factor analysis with adequate power (.85). The appropriateness of factor analysis is supported by Bartlett's test (χ2 = 7110, p ≤ .01) and the Kaiser-Meyer-Olkin measure of sampling adequacy (.91). Setting. The sample (n = 558) was composed of 3M Inc. employees from multiple sites in Austin, Texas (n = 393); employees from MuRata Electronics, Inc., College Station, Pennsylvania (n = 53); and students enrolled at the University of Texas at Austin (n = 112). Subjects. Racial, gender, and age distribution was, respectively, 6.3% African-American (n = 35), 8.2% Asian (n = 46), 73.3% Caucasian (n = 409), 9.5% Hispanic (n = 53), and 2.7% other (n = 15); 47.8% male (n...
431 citations
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TL;DR: In this article, a local geometric description of how charged matter arises in type IIA, M-theory, of Ftheory compactifications on Calabi-Yau manifolds is given.
351 citations
TL;DR: Evidence is provided that leptin, at physiological levels, can directly attenuate insulin-induced steroidogenesis of granulosa cells without affecting proliferation of this ovarian cell type, to support the hypothesis that leptin can act as a metabolic signal to the reproductive system via direct action at the ovarian level.
Abstract: Leptin, a recently-discovered hormonal product of the obese gene, circulates in the blood at levels paralleling those of fat reserves and regulates satiety and improves reproductive performance if injected into mice lacking circulating leptin. Therefore, we tested the hypothesis that leptin signals metabolic information to the reproductive system by directly affecting granulosa cell function. Doses of 10–300 ng/ml leptin had no effect (P > 0.10) on basal or insulin-induced numbers of granulosa cells cultured from small (1–5 mm) or large (≥8 mm) bovine follicles. Similarly, 30 and 300 ng/ml leptin had no effect (P > 0.10) on basal estradiol production. However, leptin, in a dose-dependent manner, inhibited (P < 0.05) insulin-induced progesterone and estradiol production by granulosa cells from small and large follicles. Leptin did not compete for specific 125I-insulin binding to granulosa cells. Furthermore, specific binding of 125I-leptin was demonstrable in granulosa cells. In conclusion, leptin, at phys...
341 citations
TL;DR: The details of hairpin structures containing trinucleotide repeats are summarized and discussed with respect to potential mechanisms of triplet repeat expansion and d(CGG.CCG) n methylation/demethylation.
Abstract: Triplet repeat expansion diseases (TREDs) are characterized by the coincidence of disease manifestation with amplification of d(CAG. CTG), d(CGG.CCG) or d(GAA.TTC) repeats contained within specific genes. Amplification of triplet repeats continues in offspring of affected individuals, which generally results in progressive severity of the disease and/or an earlier age of onset, phenomena clinically referred to as 'anticipation'. Recent biophysical and biochemical studies reveal that five of the six [d(CGG)n, d(CCG)n, (CAG)n, d(CTG)n and d(GAA)n] complementary sequences that are associated with human disease form stable hairpin structures. Although the triplet repeat sequences d(GAC)n and d(GTC)n also form hairpins, repeats of the double-stranded forms of these sequences are conspicuously absent from DNA sequence databases and are not anticipated to be associated with human disease. With the exception of d(GAG)n and d(GTG)n, the remaining triplet repeat sequences are unlikely to form hairpin structures at physiological salt and temperature. The details of hairpin structures containing trinucleotide repeats are summarized and discussed with respect to potential mechanisms of triplet repeat expansion and d(CGG.CCG) n methylation/demethylation.
297 citations
TL;DR: In this paper, the authors focus on fine abrasive processes with emphasis on material removal in brittle workmaterials, and make an attempt to rationalize various models by linking conventional machining, grinding, ultraprecision machining and indentation sliding.
282 citations
TL;DR: In this article, the physics of a 4-brane probe in type V compactification to nine dimensions are described. But this is not the case for the case of exceptional groups, which arise geometrically by a collapsing del Pezzo surface.
234 citations
TL;DR: In this paper, the complex conductivity of doped silicon from low frequencies to frequencies higher than the plasma frequency and the carrier damping rate was measured using ultrafast optoelectronic THz techniques.
Abstract: Via ultrafast optoelectronic THz techniques, we are able to test alternative theories of conduction by precisely measuring the complex conductivity of doped silicon from low frequencies to frequencies higher than the plasma frequency and the carrier damping rate. These results, obtained for both $n$ and $p$-type samples, spanning a range of more than 2 orders of magnitude in the carrier density, do not fit any standard theory. We only find agreement over the full frequency range with the complex conductivity given by a Cole-Davidson type distribution applied here for the first time to a crystalline semiconductor, and thereby demonstrate that fractal conductivity is not just found in disordered material.
TL;DR: Since the introduction of glass fiber-reinforced polymer composites in the early 1940s, composite materials development was driven by the needs of space, defense, and aircraft industries.
Abstract: Since the introduction of glass fiber-reinforced polymer composites in the early 1940s, composite materials development was driven by the needs of space, defense, and aircraft industries w...
TL;DR: In this paper, a local geometric model in terms of F-and M-theory compactification on Calabi-Yau 4-folds is constructed, which leads to N = 1 Yang-Mills theory in d = 4 and its reduction on a circle to d = 3.
TL;DR: The specific cell adhesion molecules and their ligands that may be involved in pathologic conditions and potential therapeutie strategies by modulating the expression of these molecules will be discussed.
Abstract: Cell adhesion molecules are glycoproteins expressed on the cell surface and play an important role in inflammatory as well as neoplastic diseases. There are four main groups: the integrin family, the immunoglobulin superfamily, selectins, and cadherins. The integrin family has eight subfamilies, designated as beta 1 through beta 8. The most widely studied subfamilies are beta 1 (CD29, very late activation [VLA] members), beta 2 (leukocyte integrins such as CD11a/CD18, CD11b/CD18, CD11c/CD18, and alpha d beta 2), beta 3 (CD61, cytoadhesions), and beta 7 (alpha 4 beta 7 and alpha E beta 7). The immunoglobulin superfamily includes leukocyte function antigen-2 (LFA-2 or CD2), leukocyte function antigen-3 (LFA-3 or CD58), intercellular adhesion molecules (ICAMs), vascular adhesion molecule-1 (VCAM-1), platelet-endothelial cell adhesion molecule-1 (PE-CAM-1), and mucosal addressin cell adhesion molecule-1 (MAdCAM-1). The selectin family includes E-selectin (CD62E), P-selectin (CD62P), and L-selectin (CD62L). Cadherins are major cell-cell adhesion molecules and include epithelial (E), placental (P), and neural (N) subclasses. The binding sites (ligands/receptors) are different for each of these cell adhesion molecules (e.g., ICAM binds to CD11/CD18; VCAM-1 binds to VLA-4). The specific cell adhesion molecules and their ligands that may be involved in pathologic conditions and potential therapeutic strategies by modulating the expression of these molecules will be discussed.
TL;DR: It appears that T'ai Chi Chuan presents a low-stress method to enhance stability, selected kinesthetic sense, and strength of knee extension.
Abstract: The purpose of this study was to assess the effect of T'ai Chi Chuan training on lateral stability, kinesthetic sense, and strength of voluntary knee extension. Subjects consisted of 24 naive volunteers (12 men and 12 women) between the ages of 20 and 45 years. Pre- and 12-week posttests included lateral body stability, kinesthetic sense in the glenohumeral joint for 30°, 45°, and 60°, and strength of knee extension. After pretest data collection, 12 subjects performed T'ai Chi Chuan three times per week for 12 weeks, learning 108 forms of T'ai Chi Chuan. A 2 × 2 analysis of variance was used to estimate significance of group differences on all of the dependent variables. Significant group differences were found in lateral body stability, kinesthetic sense at 60°, and strength of the dominant knee extensor. No significant differences between the T'ai Chi and the control group were found for kinesthetic sense at 30° and 45° rotation of the glenohumeral joint. Film analysis indicated that the two lesser ang...
TL;DR: In this article, the authors experimentally planted annual crop species in monoculture and polyculture, and found that the species compo- sition of weeds was similar among treatments, but the species richness of weeds were significantly higher in the polycultures than in the monoccultures.
Abstract: The ecological literature is ambiguous as to whether the initial diversity of a plant community facilitates or deters the diversity of colonizing species. We experimentally planted annual crop species in monoculture and polyculture, and ex- amined the resulting weed communities. The species compo- sition of weeds was similar among treatments, but the species richness of weeds was significantly higher in the polycultures than in the monocultures. This supports the 'diversity begets diversity' hypothesis. Environmental microheterogeneity, di- versity promoters, and ecological equivalency do not seem able to explain the observed patterns.
TL;DR: In this article, the authors extended the previous research on creativity and person-environment fit by examining fit on the dimension of creativity and by incorporating both supply-value and demand-ability versions of fit.
TL;DR: Cholesterol that was assimilated by Lactobacillus acidophilus ATCC 43121 was not metabolically degraded; most of it was recovered with the cells, and the type of fatty acid in the phospholipid did not influence the assimilation.
TL;DR: In this article, the authors analyzed the long-term basal area dynamics of dominant graminoid species across three grazing inten- sity treatments (heavily grazed, moderately grazed and ungrazed) at the Texas A&M University Agricultural Re- search Station on the Edwards Plateau, Texas.
Abstract: Long-term (45-yr) basal area dynamics of dominant graminoid species were analyzed across three grazing inten- sity treatments (heavily grazed, moderately grazed and ungrazed) at the Texas A&M University Agricultural Re- search Station on the Edwards Plateau, Texas. Grazing inten- sity was identified as the primary influence on long-term variations in species composition. Periodic weather events, including a severe drought (1951-1956), had little direct influ- ence on composition dynamics. However, the drought inter- acted with grazing intensity in the heavily grazed treatment to exacerbate directional changes caused by grazing intensity. Species response to grazing was individualistic and noisy. Three response groups were identified. Taller, more produc- tive mid-grasses were most abundant under moderate or no grazing. Short grasses were most abundant under heavy graz- ing. Intermediate species were most abundant under moderate grazing and opportunistic to weather patterns. Graminoid diver- sity increased with the removal or reduction of grazing inten- sity. The moderately and ungrazed treatments appeared most resistant to short-term weather fluctuations, while the heavily grazed treatment demonstrated significant resilience when graz- ing intensity was reduced after over 110 yr of overgrazing. Identification of a 'climax' state is difficult. Significant directional change, which took nearly 20 yr, appears to con- tinue in the ungrazed treatment after 45 yr of succession. The observed, relatively linear patterns of perennial grass compo- sition within the herbaceous patches of this savanna were generally explained by traditional Clementsian succession. However, when dynamics of the herbaceous community are combined with the woody component of this savanna, the frequency and intensity of fire becomes more important. Across the landscape, successional changes follow several pathways. When vegetation change is influenced by several factors, a multi-scale model is necessary to demonstrate interactions and feedbacks and accurately describe successional patterns. Ab- sence of fires, with or without grazing, leads ultimately to a Juniperus/Quercus woodland with grazing intensity primarily influencing the fuel load and hence fire intensity.
TL;DR: Female BALB/c mice were infested four times with pathogen-free Ixodes scapularis nymphs prior to infestation with nymphS infected with Borrelia burgdorferi B31, and one hundred percent of control mice infested only with infected ticks were culture positive for B. burgdorFERi.
Abstract: Female BALB/c mice were infested four times with pathogen-free Ixodes scapularis nymphs prior to infestation with nymphs infected with Borrelia burgdorferi B31. Each infestation was separated by a 14-day tick-free period. Mean weights of fed ticks and percentage reaching repletion did not indicate development of acquired resistance. Only 16.7% of mice repeatedly infested with pathogen-free ticks prior to infected I. scapularis nymph challenge became positive for B. burgdorferi. One hundred percent of control mice infested only with infected ticks were culture positive for B. burgdorferi.
Journal Article•
TL;DR: Recently, endometrial expression for the inter-trypsin inhibitor (I alpha I) family of protease inhibitors has been detected in the pig endometrium during conceptus elongation and attachment, suggesting that I alpha Is may function to inhibit trophoblast invasion and also serve as targets for adhesion molecules to aid in placental attachment to the uterine epithelium.
Abstract: Implantation/placentation in domestic pigs is preceded by synthesis of oestrogen by the conceptus to maintain functional corpora lutea throughout pregnancy and a rapid morphological transformation of conceptuses from spherical to long filamentous thread-like structures Initial conceptus expansion, reaching a metre in length, not only delineates the surface area for placental attachment, but also provides the mechanism for delivery of oestrogen to signal events necessary for placentation throughout the uterine horn Timing for conceptus gene expression to induce trophoblast expansion and attachment in pigs is temporally associated with downregulation of progesterone receptors and increase in oestrogen receptors within the uterine epithelium Within the confines of the uterine lumen, pig conceptuses normally do not erode or invade through the uterine epithelial surface However, the pig conceptus possesses extensive proteolytic activity as it is highly invasive outside the uterine lumen of the pig Initial release of oestrogen by the elongating pig conceptus induces endometrial release of cytokines and a variety of protease inhibitors Recently, endometrial expression for the inter-trypsin inhibitor (I alpha I) family of protease inhibitors has been detected in the pig endometrium during conceptus elongation and attachment It is possible that I alpha Is may function to inhibit trophoblast invasion and also serve as targets for adhesion molecules, such as integrins and heparin, to aid in placental attachment to the uterine epithelium
TL;DR: In this article, the shape of Optically Stimulated Luminescence (OSL) decay curves is examined, both experimentally and theoretically, in an effort to understand and describe the behavior of OSL as a function of temperature.
TL;DR: The present article reviews the most recent work on salivary gland secretion with special emphasis on how they favour pathogen transmission, and investigates the role of saliva in the transmission and establishment of tick‐borne pathogens.
Abstract: Secretions of the tick salivary glands are essential to the successful completion of the prolonged feeding of these ectoparasites as well as the conduit by which most tick-borne pathogens are transmitted to the host. In ixodid ticks the salivary glands are the organs of osmoregulation, and excess water from the bloodmeal is returned via saliva into the host. Host blood must continue to flow into the feeding lesion as well as remain fluid in the tick mouthparts and gut. The host's haemostatic mechanisms are thwarted by various anti-platelet aggregatory, anticoagulatory and anti-vasoconstrictory factors in tick saliva. Saliva components suppress the immune and inflammatory response of the host permitting the ticks to remain on the host for an extended period of time and, adventitiously, enhancing the transmission and establishment of tick-borne pathogens. Over the years much work has been done on the numerous enzyme and pharmacological activities found in the tick saliva. The present article reviews the most recent work on salivary gland secretions with special emphasis on how they favour pathogen transmission.
TL;DR: Recent advances in understanding tick-host immunology are discussed, and future studies are proposed to exploit these interactions and exploit them in novel immunological control strategies.
TL;DR: In this paper, a model of thermomechanical shear instability in high-speed machining of some difficult-to-machine materials leading to shear localization is presented.
TL;DR: In this article, an intermolecular potential that describes the structure of the α-form of the hexahydro-1,3,5-trinitro- 1,3-5-s-triazine (RDX) crystal was developed.
Abstract: We have developed an intermolecular potential that describes the structure of the α-form of the hexahydro-1,3,5-trinitro-1,3,5-s-triazine (RDX) crystal. The potential is composed of pairwise atom−atom (6-exp) Buckingham interactions and charge−charge interactions. The parameters of the Buckingham repulsion−dispersion terms have been determined through a combination of nonlinear least-squares fitting to observed crystal structures and lattice energies and trial-and-error adjustment. Crystal packing calculations were performed to determine the equilibrium crystallographic structure and lattice energy of the model. There are no significant differences in the geometrical structures and crystal energies resulting from minimization of the lattice energy with and without symmetry constraints. Further testing of the intermolecular potential has been done by performing symmetry-constrained isothermal−isobaric Monte Carlo simulations. The properties of the crystal (lattice dimensions, molecular orientation, and lat...
TL;DR: Data indicate that PSTVd moves from cell to cell via plasmodesmata, and this movement may be mediated by a specific sequence or structural motif.
Abstract: Viroids are non-translatable, autonomously replicating circular RNAs that infect only plants. An important component of the viroid infection process is cell-to-cell movement; however, there is virtually no information available about the pathways and mechanisms of this process. In this study, potato spindle tuber viroid (PSTVd) has been used as a model system to investigate the mechanism of viroid cell-to-cell transport. Infectious RNA transcripts were produced from PSTVd cDNA clones in vitro, labeled with the nucleotide-specific fluorescent dye TOTO-1 iodide, and used for micro-injection. When injected into symplasmically isolated guard cells of mature tomato and tobacco leaves, PSTVd remained in the injected cells; in contrast, PSTVd injected into symplasmically connected mesophyll cells moved rapidly from cell to cell. A 1400 nt RNA containing only vector sequences was unable to move out of the injected mesophyll cells, but when PSTVd was fused to this transcript, the fusion RNA moved from cell to cell. At the DNA level, PSTVd cDNA also appears able to mediate cell-to-cell movement of plasmid DNA. These data indicate that (i) PSTVd moves from cell to cell via plasmodesmata, and (ii) this movement may be mediated by a specific sequence or structural motif.
TL;DR: The purpose of the experiments reported here was to determine bacteriophage-host interactions under environmentally relevant conditions of nutrient limitation, and revealed the importance of a phenomenon called pseudolysogeny in the maintenance of viral genetic material for extended periods of time in natural ecosystems.
Abstract: Bacteriophages occur in high numbers in environmental ecosystems and are thus significant mediators of microbial survival and activities. However, interactions between microbial populations and phages in situ have been largely ignored. Current understanding of the process relies on studies performed with well-fed, laboratory-grown host bacteria. The purpose of the experiments reported here was to determine bacteriophage-host interactions under environmentally relevant conditions of nutrient limitation. These studies have revealed the importance of a phenomenon called pseudolysogeny in the maintenance of viral genetic material for extended periods of time in natural ecosystems. Pseudolysogeny is a form of phage-host cell interaction in which the nucleic acid of the phage resides within its starved host in an unstable, inactive state. It is hypothesized that pseudolysogeny occurs due to the cell's highly starved condition. In such cells, there is insufficient energy available for the phage to initiate genetic expression leading to either a true temperate response or to the lytic response. However, upon nutrient addition, the pseudolysogenic state is resolved, resulting in either the establishment of true lysogeny or the initiation of the lytic production of progeny virions. The pseudolysogenic state may explain the long-term survival of viruses in unfavourable environments in which the infective half-life of their virions is relatively short.
TL;DR: The role of semiochemicals in stored-product pest management is increasing as more biorational methods are employed and host-finding efficiency of natural enemies in biological control programs could be improved with the use of kairomones in mass-rearing or release protocols.
TL;DR: Two studies were conducted to assess separateness-connectedness (SC) as a new message variable and individual difference variable in advertising as discussed by the authors, and the results revealed that individuals with a separate self-schema preferred a separated advertising theme, and those with a connected self-schemas preferred a connected advertising theme.
Abstract: Two studies were conducted to assess separateness-connectedness (SC) as a new message variable and as a new individual difference variable in advertising. Study I began the process of developing a Separateness-Connectedness scale based on a sample of 140 college students (97 Westerners and 43 non-Westerners, 81 males and 59 females) attending a midwestern university. The 9-item, 2-factor scale revealed good reliability and construct validity. The structure of the overall model was then successfully tested on a new sample by confirmatory factor analysis. In Study II an experiment assessed whether the separateness/connectedness self-schema would moderate the effect of using either a connected or a separated advertising appeal on consumers' attitude toward the ad. As predicted, a significant interaction effect was found. The results revealed that individuals with a separate self-schema preferred a separated advertising theme, and individuals with a connected self-schema preferred a connected advertising theme. Implications for advertising managers, the studies' limitations, and future research directions are also discussed. © 1997 John Wiley & Sons, Inc.