Showing papers by "North Carolina State University published in 1987"

The impact of corporate characteristics on social responsibility disclosure: A typology and frequency-based analysis

Abstract: Since the mid-1970s a number of studies have investigated the nature and frequency of corporate social responsibility disclosures, their patterns and trends, and their general relationships to corporate size and profitability. This study seeks to extend our knowledge of the relationship between a number of corporate characteristics and specific types of social responsibility disclosures, based on an extensive sample of U.S. corporate annual reports. Corporate size and industry category are found to correlate with certain types of disclosures while the existence of a corporate social responsibility committee appears to correlate with one particular type of disclosure.

Variance Function Estimation

Abstract: Heteroscedastic regression models are used in fields including economics, engineering, and the biological and physical sciences. Often, the heteroscedasticity is modeled as a function of the covariates or the regression and other structural parameters. Standard asymptotic theory implies that how one estimates the variance function, in particular the structural parameters, has no effect on the first-order properties of the regression parameter estimates; there is evidence, however, both in practice and higher-order theory to suggest that how one estimates the variance function does matter. Further, in some settings, estimation of the variance function is of independent interest or plays an important role in estimation of other quantities. In this article, we study variance function estimation in a unified way, focusing on common methods proposed in the statistical and other literature, to make both general observations and compare different estimation schemes. We show that there are significant di...

Determining the Order of Differencing in Autoregressive Processes

Abstract: One way of handling nonstationarity in time series is to compute first differences and fit a model to the differenced series unless the differenced series also looks nonstationary. In that case, second- or higher-order differencing is done. To decide if the current degree of differencing is sufficient, one can look at the autocorrelation function for slow decay. A formal statistical test for the need to difference further is available if one is willing to assume that at most one more difference will render the series stationary. In this article, we present a proper sequence of statistical tests that allows the practitioner to handle cases in which a high order of differencing may be needed. The proper sequence is not the traditional sequence, which begins with a test for a single unit root.

Reconciling Bayesian and Frequentist Evidence in the One-Sided Testing Problem

Abstract: For the one-sided hypothesis testing problem it is shown that it is possible to reconcile Bayesian evidence against H 0, expressed in terms of the posterior probability that H 0 is true, with frequentist evidence against H 0, expressed in terms of the p value. In fact, for many classes of prior distributions it is shown that the infimum of the Bayesian posterior probability of H 0 is equal to the p value; in other cases the infimum is less than the p value. The results are in contrast to recent work of Berger and Sellke (1987) in the two-sided (point null) case, where it was found that the p value is much smaller than the Bayesian infimum. Some comments on the point null problem are also given.

Fracture of nonhomogeneous materials

Abstract: The nonhomogeneous materials considered in this work are of a class whose elastic moduli are specified by continuous and generally differentiable functions of the spatial coordinates. The elastic stress and displacement fields near a crack tip in a two-dimensional nonhomogeneous cracked body are derived utilizing an extension of the Wiliams eigenfunction expansion technique. The nature of the stress and strain singularity is ascertained to be precisely of the same form as the well-known inverse square root stress singularity near a crack tip in a homogeneous material, independent of the functional form of the elastic moduli variation. A new quasipath-independent integral has been generated which proves useful for computing the energy release rate and mixed-mode stress intensity factors in nonhomogeneous cracked bodies. The integral is used in conjunction with finite element analysis for purposes of computing stress intensity factors. Numerical results are compared with certain exact solutions which are available for nonhomogeneous cracked bodies. Cracked composite bodies have traditionally been modeled and analyzed as possessing discontinuous elastic moduli, but are treated here as having rapid, but smooth variations of the material properties.

Cognitive Science: An Introduction

Abstract: Cognitive Science is a single-source undergraduate text that broadly surveys the theories and empirical results of cognitive science within a consistent computational perspective. In addition to covering the individual contributions of psychology, philosophy, linguistics, and artificial intelligence to cognitive science, the book has been revised to introduce the connectionist approach as well as the classical symbolic approach and adds a new chapter on cognitively related advances in neuroscience. Cognitive science is a rapidly evolving field that is characterized by considerable contention among different views and approaches. Cognitive Science presents these in a relatively neutral manner. It covers many new orientations theories and findings, embedding them in an integrated computational perspective and establishing a sense of continuity and contrast with more traditional work in cognitive science. The text assumes no prerequisite knowledge, introducing all topics in a uniform, accessible style. Many topics, such as natural language processing and vision, however, are developed in considerable depth, which allows the book to be used with more advanced undergraduates or even in beginning graduate settings. A Bradford Book

Conditional scores and optimal scores for generalized linear measurement-error models

Abstract: : This paper studies estimation of the parameters of generalized linear models in canonical form when the explanatory vector is measured with independent normal error. For the functional case, i.e., when the explanatory vectors are fixed constants, unbiased score functions are obtained by conditioning on certain sufficient statistics. This work generalizes results obtained for logistic regression. In the case that the explanatory vectors are independent and identically distributed with unknown distribtuion, efficient score functions are obtained using the theory developed in Begun et al. (1983). Keywords: Conditional score function; Efficient score function; Functional model; Generalized linear model; Measurement error; Structural model.

An analysis of nonlinear behavior in delta - sigma modulators

Abstract: This paper introduces a new method of analysis for deltasigma modulators based on modeling the nonlinear quantizer with a linearized gain, obtained by minimizing a mean-square-error criterion [7], followed by an additive noise source representing distortion components. In the paper, input signal amplitude dependencies of delta-sigma modulator stability and signal-to-noise ratio are analyzed. It is shown that due to the nonlinearity of the quantizer, the signal-to-noise ratio of the modulator may decrease as the input amplitude increases prior to saturation. Also, a stable third-order delta-sigma modulator may become unstable by increasing the input amplitude beyond a certain threshold. Both of these phenomena are explained by the nonlinear analysis of this paper. The analysis is carried out for both dc and sinusoidal excitations.

A mitochondrial protein associated with cytoplasmic male sterility in the T cytoplasm of maize.

Abstract: Mitochondrial DNA in the T male-sterile cytoplasm (cms-T) of maize contains an open reading frame (ORF 13) associated with the T type of sterility. Antibodies raised to a chemically synthesized oligopeptide corresponding to ORF 13 were used to establish the expression of a 13-kDa protein from this reading frame. The 13-kDa polypeptide is synthesized uniquely in cms-T maize and purifies with the membrane fraction of T mitochondria. We assign the symbol urf13-T to designate this mitochondrial gene. Presence of the nuclear restorer gene Rf1 in cms-T plants results in a decrease in abundance of 13-kDa protein and alteration in the transcripts of urf13-T.

Variability in oil quality among peanut genotypes in the Florida breeding program

Abstract: The improvement of peanut (Arachis hypogaea L.) oil quality has long been an objective of the Florida breeding program, since it influences the shelf-life and nutritional quality of manufactured products. Fatty acid distribution of the peanut genotypes (228 in 1984 and 298 in 1985) from the Gainesville and Marianna locations was determined by gas-liquid chromatography. A wider range in fatty acid composition, especially in oleic and linoleic acids, was found among these genotypes than that reported previously in the literature for the cultivated peanut. Two closely related experimental lines (435–2–1 and 435–2–2) had 80% oleic and 2% linoleic acid, with iodine values of 74. For the Florida breeding lines, iodine values of the oil ranged from 74 to 107 and the oleic/linoleic (O/L) ratios from 0.9 to 35:1. Florunner, by comparison, has an iodine value of 95 and an O/L ratio of slightly less than 2. The oleic acid content of the different experimental lines ranged from 37% to 80%, and the linoleic a...

Dry etching of silicon carbide

Abstract: The invention comprises a method of etching silicon carbide targets. In one embodiment, a reactive ion plasma is formed from a gas which is easily dissociated into its elemental species in the plasma, for which all of the dissociated elemental species are volatile in the plasma, and for which at least one of the elemental species is reactive with silicon carbide. The silicon carbide target to be etched is positioned on one of the electrodes which is formed from a material with a low sputter yield and which material reacts with a dissociated species to thereby prevent contamination of the target with either sputtered materials from the electrode or polymerized species from the plasma.

A Survey and Comparision of Fault-Tolerant Multistage Interconnection Networks

Abstract: Today all branches of engineering and a multitude of other disciplines rely firmly and increasingly on computational support. However, each discipline has important problems that, to be solved feasibly, await our ability to field computers with orders of magnitude greater performance than currently available. Consequently, the need for very high performance computing is larger than ever and growing. To date, high-performance computers have owed their speed primarily to advances in circuit and packaging technology. These technologies are subject to physical limits constraining the ultimate speed of a conventional uniprocessor computer. Parallel processing computers executing problems solutions expressed as parallel algorithms translated into parallel machine programs can exceed the single processor speed limit. The means for communication among processors, memory modules, and other devices of a parallel computer is the interconnection network.

Resource Mobilization Through Ethnic Networks: Kinship and Friendship Ties of Shopkeepers in England

Abstract: Shopkeepers have social networks composed of ties to many others: Family, friends, customers, suppliers, employees, and moneylenders. We examine how ties to family and friends affect three aspects of entrepreneurship for Asian and white shop owners in four English cities: Business foundings, business success, and business turnover. Social ties are important for all three processes in both groups. An implication of our research is that the comparative study of immigrant and native groups shifts the focus from group differences to group similarities. Studies examining only immigrants may find apparently distinctive characteristics, but, in fact, many traits are common to all small-business owners, given the turbulent environment they face.

Small nuclear inclusion protein encoded by a plant potyvirus genome is a protease.

Abstract: Tobacco etch virus, a plant potyvirus, expresses its RNA genome as a large polyprotein precursor which undergoes extensive proteolytic processing to yield seven or more mature products Two of these products, proteins with apparent molecular weights of 49,000 and 54,000 (49K and 54K proteins), aggregate in the form of crystalline inclusions within the nuclei of infected cells Cell-free translation of synthetic transcripts was used to map the genes for these two products on the viral genome and to express an enzymatically active protein The 49K protein was determined to be a viral protease responsible for several cleavages of the polyprotein, including its own autocatalytic excision Analyses of products expressed from the 49K protein genes which were altered by deletion revealed that only the carboxyl-terminal half was required for proteolytic activity

Global existence and boundedness in reaction-diffusion systems

Abstract: In many applications, systems of reaction-diffusion equations arise in which the nature of the nonlinearity in the reaction terms renders ineffective the standard techniques (such as invariant sets and differential inequalities) for establishing global existence, boundedness, and asymptotic behavior of solutions. In this paper we prove global existence and uniform boundedness for a class of reaction-diffusion systems involving two unknowns in which an a priori bound is available for one component as long as solutions exist. Among this class of systems is the so-called Brusselator, a model from the study of instabilities in chemical processes.

Conjugal Transfer of Plasmid-Encoded Determinants for Bacteriocin Production and Immunity in Lactobacillus acidophilus 88.

Abstract: Lactobacillus acidophilus 88 produced a bacteriocin, designated lactacin F, that demonstrated inhibitory activity toward L. acidophilus 6032, L. lactis 970, L. helveticus 87, L. bulgaricus 1489, L. leichmanii 4797, L. fermentum 1750, and Streptococcus faecalis 19433. Production of lactacin F was pH dependent and could be maximized in MRS broth cultures maintained at pH 7.0. Lactacin F was heat stable and sensitive to ficin, proteinase K, trypsin, and Bacillus subtilis protease. L. acidophilus 88 harbored plasmids of 4 and 27 megadaltons. Variants of L. acidophilus 88 which were deficient in lactacin F production (Laf) and lactacin F immunity (Laf) retained the two resident plasmids. A Laf Laf derivative, L. acidophilus 89, was used as a recipient in agar surface mating experiments with L. acidophilus 88 (Laf Laf). Two types of Laf Laf transconjugants were recovered. One type (T-E) had acquired two plasmids of 68 (pPM68) and 52 (pPM52) megadaltons that were not detected in either the conjugal donor or the other type of Laf Laf transconjugants (T-89). Laf and Laf were unstable in the plasmid-bearing transconjugant. Plasmid analysis of Laf Laf variants revealed that pPM52 and pPM68 were cured with loss of Laf and Laf. Bacteriocin production and immunity phenotypes were genetically stable in Laf Laf transconjugants not harboring pPM52 and pPM68, suggesting chromosomal integration of the transferred determinants. The data demonstrated intragenic conjugation in L. acidophilus and provided direct evidence for involvement of transient plasmid determinants in Laf and Laf.

Microbial ecology of fermenting plant materials

Abstract: The lactic acid fermentation of plant materials is presented from an ecological perspective emphasizing microbial interactions and their influence on the production of fermented plant foods and silage. The plant lactic acid bacteria are discussed in terms of evolution; epiphytic function; physical distribution within fermented material; substrates and products; microbial sequences in fermentation; interactions among species; pure culture fermentation; and starter culture development.

Formation of thin superconducting films by the laser processing method

Abstract: We have prepared thin films of Y‐Ba‐Cu‐O superconductors using a pulsed laser evaporation technique. Thin films were formed on (100) Si, (100) MgO, (1102) sapphire, (100) SrTiO3, and amorphous SiO2 substrates using a XeCl excimer laser (λ=0.308 μm, τ=45×10−9 s). The depositions were done in an ultrahigh vacuum chamber with pressure of about 10−6 Torr during thin‐film formation. The deposition by pulsed nanosecond laser irradiation results in stoichiometry close to that of the target. The thickness of the film was controlled by varying the pulse energy density and the number of pulses. The substrate temperature was kept at 470 °C during deposition. Subsequent annealing treatments were carried out at 900 and 650 °C in oxygen atmosphere to recover the superconducting properties of these thin films. The resistance of these films was measured as a function of temperature using the four‐point probe method. These thin films were analyzed using cross‐section transmission electron microscopy, Rutherford backscatt...

Loss Leader Pricing and Rain Check Policy

Abstract: Loss leader pricing and rain check policies are common in retail markets, yet research on these topics is surprisingly scarce. In this paper, we study the effects of leader pricing and rain check policy on stores' profits and market outcomes. Suppose stores can accurately predict demand. Might they still run out of stock? We investigate whether such a result is plausible when stores can offer rain checks. The paper also helps resolve an issue that has recently attracted much attention: Should the FTC repeal its rule prohibiting stock outs of advertised sale items?

HPLC Separation of Cis-Trans Carotene Isomers in Fresh and Processed Fruits and Vegetables

Abstract: Resolution of cis-trans alpha- and beta-carotene isomers was achieved using a rapid (30 min) high-performance liquid chromatography method employing a slurry-packed calcium hydroxide column. The isomers found in fruit and vegetable products were identical to those formed through iodine catalyzed isomerization of carotene solutions. A survey of fresh and commercially processed fruit and vegetable products indicated that the greatest percentage of isomers was found in processed foods (20.1–54.0%). Of the fresh products surveyed, cis-isomers were found in plums, nectarines and peaches, and no cis-isomers were detected in sweet potatoes, carrots and tomatoes; however, all fresh green vegetables contained from 19.6–28.3% monocis-isomers.

Flavor Constituents of Beef as Influenced by Forage‐ and Grain‐Feeding

Abstract: Hereford yearling steers (N= 144) were alloted to one of three pasture systems: tall fescue, smooth bromegrass-red clover or orchardgrass-red clover. After the grazing period, steers were finished in drylot and then serially slaughtered at 0, 56, 84 and 112 days. Carcass quality grades and yield grade numbers increased when steers were fed grain up to 112 days. Tenderness of loin steaks increased up to 84 days, after which no improvements were observed. Sensory panel scores for grassy flavor of steaks and ground beef decreased up to 112 days. Fifty-three compounds were identified in the volatiles of melted subcutaneous fat by direct sampling-gas chromatography/mass spectro-metry. The major differences between volatiles from fat of forage-fed compared to grain-fed steers were the higher concentrations of 2,3-octanedione and various diterpenoids present in the samples of the forage-fed animals.

Exploration of Mechanisms Regulating Larval Survival in Lake Michigan Bloater: A Recruitment Analysis Based on Characteristics of Individual Larvae

Abstract: Estimates of relative egg deposition and larval abundance suggest that events occurring between spawning and the first 1–2 months after hatching play a major role in determining recruitment success of bloater Coregonus hoyi in Lake Michigan. Although relative egg deposition in 1983 was only 57% of that in 1982, larval recruitment was 2.4 times greater in 1983. We investigated mechanisms governing survival of larval bloaters by comparing characteristics of individual “survivors” through the first 1–2 months of life with those of larvae at earlier life history stages. Otolith analysis was used to identify stress periods and to determine ages, first-feeding dates (close correlates of birthdate), and average growth rates of individual bloater larvae from hatching to nearly 2 months of age in 1982 and 1983. Differences between the observed distribution of first-feeding dates for newly hatched larvae and the expected distribution predicted from egg deposition showed that eggs spawned early experienced ...

Galactinol Synthase Activity and Soluble Sugars in Developing Seeds of Four Soybean Genotypes

Abstract: Galactinol synthase (UDP-galactose:inositol galactosyltransferase) is the first unique enzyme in the biosynthetic pathway of raffinose saccharides. Its role as a regulator of carbon partitioning between sucrose and raffinose saccharides in developing soybean (Glycine max L. Merrill) seeds was examined. Galactinol synthase activity and concentrations of sucrose, stachyose, and raffinose were compared during seed development between two genotypes that were high and two genotypes that were low in mature seed raffinose saccharide concentration. In all genotypes, sucrose concentration increased as seed development progressed, but in both low raffinose saccharide genotypes, greater increases in sucrose concentration were observed late in seed development. Sucrose to stachyose ratios in mature seeds were 2.3-fold greater in low raffinose saccharide genotypes than in the high raffinose saccharide genotypes. During seed development, higher levels of galactinol synthase activity were observed in the high raffinose saccharide genotypes than in the low raffinose saccharide genotypes. A common linear relationship for all four soybean genotypes was shown to exist between galactinol formed estimated from galactinol synthase activity data and the concentration of galactose present in raffinose saccharides. Results of this study implied that galactinol synthase is an important regulator of carbon partitioning between sucrose and raffinose saccharides in developing soybean seeds.

The legitimate concern with fairness.

Abstract: Decision usefulness has become a central principle for organizing accounting research and practice. Arguments presented in this paper demonstrate two serious conceptual problems with a singular reliance upon decision usefulness: assuming the symmetry of decision usefulness and ignoring the simultaneity of efficiency and distributive effects. Arguments are provided supporting a concept of fairness as a construct necessary to provide accounting with a lexicon complete enough to discuss accounting problems.

Homoepitaxial growth of alpha-SiC thin films and semiconductor devices fabricated thereon

Abstract: Device quality monocrystalline Alpha-SiC thin films are epitaxially grown by chemical vapor deposition on Alpha-SiC [0001] substrates prepared off axis.

The classification of 2 × 2 systems of non‐strictly hyperbolic conservation laws, with application to oil recovery

Abstract: On considere un systeme 2×2 a une variable d'espace: U + +F(U) x =0, −∞ 0, ou U=U(x,t)∈R 2 et F:R 2 →R 2 . On montre que, pour des equations hyperboliques, des points ombilicaux sont typiquement isoles et que en un point ombilical isole dF est typiquement diagonalisable. On donne une classification des equations hyperboliques a points ombilicaux isoles