Showing papers by "University of South Carolina published in 1994"

Social Network Analysis: Methods and Applications

Abstract: Part I. Introduction: Networks, Relations, and Structure: 1. Relations and networks in the social and behavioral sciences 2. Social network data: collection and application Part II. Mathematical Representations of Social Networks: 3. Notation 4. Graphs and matrixes Part III. Structural and Locational Properties: 5. Centrality, prestige, and related actor and group measures 6. Structural balance, clusterability, and transitivity 7. Cohesive subgroups 8. Affiliations, co-memberships, and overlapping subgroups Part IV. Roles and Positions: 9. Structural equivalence 10. Blockmodels 11. Relational algebras 12. Network positions and roles Part V. Dyadic and Triadic Methods: 13. Dyads 14. Triads Part VI. Statistical Dyadic Interaction Models: 15. Statistical analysis of single relational networks 16. Stochastic blockmodels and goodness-of-fit indices Part VII. Epilogue: 17. Future directions.

Relationship Lending and Lines of Credit in Small Firm Finance

Abstract: This paper examines the role of relationship lending in small firm finance. We examine price and nonprice terms of bank lines of credit (L/C) extended to small firms. Our focus on bank L/Cs allows us toe examine a type of loan contract in which the bank-borrower relationship is likely to be an important mechanism for solving asymmetric information problems associated with financing small enterprises. We find that borrowers with longer banking relationships pay lower interest rates and are less likely to pledge collateral. These results are consistent with theoretical arguments that relationship lending generates valuable information about borrower quality.

Perceived Service Quality and User Satisfaction with the Information Services Function

Abstract: A constant concern of management information systems (MIS) researchers and practitioners has been improving user satisfaction with the information services function (USISF). Due to the growth of end-user computing, decentralization, and alternative sources of supply, an organization's information services function (ISF) is now faced with serving customers that possess substantial discretion in their use and purchase of information systems (IS) services. This increasingly market-oriented environment demands sensitivity to IS customers' expectations and perceived value of ISF services. One important source of guidance in such an IS management environment is to look at marketing literature for frameworks that may permit the ISF to more effectively determine and convey the value of their services. Recognizing the need to improve existing MIS measures of user satisfaction with the ISF, this study adapts the SERVQUAL measure from marketing to provide more specific information about user satisfaction with the information service function. It was found that, while the three original dimensions of the traditional user information satisfaction (UIS) measure remain strong predictors of overall ISF user satisfaction, two aspects of IS service quality, “reliability” and “empathy,” are also significant predictors. The results suggest that the original dimensions of UIS may not be comprehensive enough to capture the more detailed dimensions of ISF service quality in SERVQUAL, and that the reliability and empathy dimensions of service quality may be needed to supplement the traditional UIS measure in determining user satisfaction with the information services function. Implications for research and practice resulting from these findings are discussed.

The Decision to Retire Early: A Review and Conceptualization

Abstract: This article explores three interconnected decisions related to early retirement- the decision whether to leave a long-term job prior to age 65. the decision whether to accept bridge employment, and the decision whether to obtain bridge employment in the same industry or occupation as the last job- and the relationships among these three decisions and adjustment to retirement. In addition, this article examines the key variables that influence these three decisions, integrating previous research on individual-level, family-level, job- and career-related, organization-level, and environmental-level factors. The article concludes with an examination of methodological issues in the study of early retirement decisions and provides directions for future theory development.

Working memory and retrieval: a resource-dependent inhibition model.

Abstract: Four experiments examined individual differences in working memory (WM) capacity and how those differences affect performance on retrieval from both primary and secondary memory. The results showed that WM differences appear only in retrieval from primary memory and then only under conditions that lead to interference or response competition within the task. This suggests that WM capacity is important to retrieval that is based on controlled effortful search but not search that is based on automatic activation. A view is presented suggesting that individual differences in attentional resources lead to differences in the ability to inhibit or suppress irrelevant information. The paradigm also allowed more general comparisons between the processes involved in retrieval from primary and secondary memory. As expected, it was found that retrieval from primary memory was a function of set size. However, for sets larger than 2 items, retrieval from secondary memory was independent of set size.

The effects of industry growth and strategic breadth on new venture performance and strategy content

Abstract: A sample of 123 independent new ventures was classified into four industry growthlstrategic breadth categories. High growth industry environments were found to provide a favorable environment for new ventures to achieve sales growth; however, the highest sales growth rates were exhibited by new ventures pursuing broad breadth strategies in high growth industries. One-way ANOVA and contrast tests were also used to identify whether specific strategic variables varied across the four industry growth/strategic breadth combinations. New ventures in high growth industries chose to enter on a larger, more aggressive scale and placed more emphasis on new product development than those entering low growth industries. Broad breadth strategy ventures had higher levels of advertising and promotion expenses and placed greater emphasis on the dominance of marketing expertise in their top management team, developing new channels of distribution, and on brand name recognition. Ventures pursuing focus strategies emphasized specialty products and were less cost conscious.

Glycation, glycoxidation, and cross-linking of collagen by glucose. Kinetics, mechanisms, and inhibition of late stages of the Maillard reaction.

Abstract: The Maillard or browning reaction between sugar and protein contributes to the increased chemical modification and cross-linking of long-lived tissue proteins in diabetes. To evaluate the role of glycation and oxidation in these reactions, we have studied the effects of oxidative and antioxidative conditions and various types of inhibitors on the reaction of glucose with rat tail tendon collagen in phosphate buffer at physiological pH and temperature. The chemical modifications of collagen that were measured included fructoselysine, the glycoxidation products N epsilon-(carboxymethyl)lysine and pentosidine and fluorescence. Collagen cross-linking was evaluated by analysis of cyanogen bromide peptides using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by changes in collagen solubilization on treatment with pepsin or sodium dodecylsulfate. Although glycation was unaffected, formation of glycoxidation products and cross-linking of collagen were inhibited by antioxidative conditions. The kinetics of formation of glycoxidation products proceeded with a short lag phase and were independent of the amount of Amadori adduct on the protein, suggesting that autoxidative degradation of glucose was a major contributor to glycoxidation and cross-linking reactions. Chelators, sulfhydryl compounds, antioxidants, and aminoguanidine also inhibited formation of glycoxidation products, generation of fluorescence, and cross-linking of collagen without significant effect on the extent of glycation of the protein. We conclude that autoxidation of glucose or Amadori compounds on protein plays a major role in the formation of glycoxidation products and cross-liking of collagen by glucose in vitro and that chelators, sulfhydryl compounds, antioxidants, and aminoguanidine act as uncouplers of glycation from subsequent glycoxidation and cross-linking reactions.

Frequency of obsessive-compulsive disorder in a community sample of young adolescents.

Abstract: Objective To investigate the incidence, transition probabilities, and risk factors for obsessive-compulsive disorder (OCD) and subclinical OCD in adolescents. Method A two-stage epidemiological study originally designed to investigate depression was conducted between 1987 and 1989 in the southeastern United States. For the screening, a self-report depressive symptom questionnaire was administered to a community sample of 3,283 adolescents. In the diagnostic stage, the Schedule for Affective Disorders and Schizophrenia for School-Age Children was administered to 488 mother–child pairs. Baseline screening and diagnostic data from the first year the subject completed an interview and follow-up diagnostic data from subsequent years were used. Results The 1-year incidence rates of OCD and subclinical OCD were found to be 0.7% and 8.4%, respectively. Transition probabilities demonstrated a pattern of moving from more severe to less severe categories. Of those with baseline OCD, 17% had the diagnosis of OCD at follow-up; 62% moved to the referent group. Of those with baseline subclinical OCD, 1.5% had OCD at follow-up and 75% moved to the referent group. Black race (odds ratio [OR] = 23.38), age (OR = 4.02), desirable life events (OR = 0.78), undesirable life events (OR = 1.21), and socioeconomic status (OR not estimable) were significant predictors of incident OCD. Age (OR = 2.30), desirable life events (OR = 0.92), and undesirable life events (OR = 1.13) were significantly associated with incident subclinical OCD. Conclusion An initial diagnosis of subclinical OCD was not significantly predictive of a diagnosis of OCD at 1-year follow-up. The overall morbidity remained higher at follow-up in the baseline OCD group than in the baseline subclinical OCD group. The baseline subclinical OCD group was more dysfunctional at follow-up than was the baseline referent group. Further research concerning differences in symptomatology and impairment between OCD and subclinical OCD is warranted.

Impact of agency risks and task uncertainty on venture capitalist-ceo interaction

Abstract: This study examined the impact of agency risks and task uncertainty on venture capitalist-chief executive officer (VC-CEO) interaction. Results from 51 VC-CEO dyads indicate that the frequency of interaction depends on the extent of VC-CEO goal congruence, the degree of the CEO's new venture experience, the venture's stage of development, and the degree of technical innovation it is pursuing. However, contrary to conventional expectations, the degree of management ownership had no impact on the frequency of interaction.

Resolving the paradox of conflict, strategic decision making, and organizational performance

Abstract: Strategic decision making influences organizational performance. However, close examination of this relationship reveals a subtle paradox. It appears that the products of strategic decision making, all of which are necessary for enhanced organizational performance, do not peacefully coexist. Conflict seems to be the crux of this conundrum. As such, a better understanding of conflict's effects on strategic decision making is needed This paper integrates a multidimensional conceptualization of conflict Into a model of strategic decision making and organizational performance and develops propositions to guide empirical study of the effects of conflict on strategic decision making.

Family-Based Treatment for Childhood Antisocial Behavior: Experimental Influences on Dropout and Engagement.

Abstract: Antisocial behavior in childhood and adolescence is an unquestionably serious problem for society. Family-based treatments are promising but face the challenging obstacle of premature parental dropout. To systematically study dropout, we randomly assigned 147 families with a markedly aggressive child (age 4 to 9 years) to a standard family treatment (SFT) focusing exclusively on parental management or to an enhanced family treatment (EFT) that also promoted frequent discussions of adult issues. EFT produced a significantly lower dropout rate than SFT overall, but particularly for high-adversity families. Dropouts were clearly distinguishable from completers on several dimensions. The results underscore the importance of addressing contextual variables such as family adversity in the treatment of childhood antisocial behavior.

Correlates and Consequences of Early Initiation of Sexual Intercourse.

Abstract: This cross-sectional analysis of the 1991 CDC Youth Risk Behavior Survey explored factors associated with an early age at first sexual intercourse. Almost 18% of White males, 49% of Black males, 5% of White females and 12% of Black females were sexually active before age 13. Carrying a weapon to school, fighting, and early (< age 13) experimentation with cigarettes and alcohol were associated with early initiation of sexual activity for all four race and gender groupings. Those initiating sexual activity early had greater numbers of partners but were 50% less likely to use condoms regularly and were two-seven times more likely to have been pregnant or caused a pregnancy. Females who initiated sexual activity early were more likely to have had a sexually transmitted disease (STD). Interventions to postpone sexual activity need to be tailored to the ethnic and gender differences observed in these analyses. Interventions must begin before age 13 and should be comprehensive school-based efforts.

Total Cholesterol and High Density Lipoprotein Cholesterol as Important Predictors of Erectile Dysfunction

Abstract: Although erectile dysfunction is frequently seen in patients with manifestations of arteriosclerotic disease, the independent contribution of serum cholesterol in predicting erectile dysfunction is unclear The aim of this study was to examine the relation between serum cholesterol and erectile dysfunction Medical histories, physical examinations, and blood tests were obtained at Cooper Clinic, Dallas, Texas, from 3,250 men aged 26-83 years (mean, 51 years) without erectile dysfunction at their first visit, who had one more clinic visit, all between 1987 and 1991 These men were followed 6-48 months after the first clinic visit (mean, 22 months) Erectile dysfunction was reported in 71 men (22%) during follow-up Every mmol/liter of increase in total cholesterol was associated with 132 times the risk of erectile dysfunction (95% confidence interval 104-168), while every mmol/liter of increase in high density lipoprotein cholesterol was associated with 038 times the risk (95% confidence interval 018-080) Men with a high density lipoprotein cholesterol measurement over 155 mmol/liter (60 mg/dl) had 030 times the risk (95% confidence interval 009-103) as did men with less than 078 mmol/liter (30 mg/dl) Men with total cholesterol over 621 mmol/liter (240 mg/dl) had 183 times the risk (95% confidence interval 100-337) as did men with less than 465 mmol/liter (180 mg/dl) Those differences remained essentially unchanged after adjustment for other potential confounders The authors conclude that a high level of total cholesterol and a low level of high density lipoprotein cholesterol are important risk factors for erectile dysfunction

Business Process Reengineering: Charting a Strategic Path for the Information Age

Abstract: Many organizations are undergoing major restructuring efforts in order to be viable in today's changing economic environment. Business process redesign (BPR), which involves the radical redesign of age-old business processes, represents one such effort. Information technologies (IT) play an important role in BPR. This article presents a framework for examining business processes based on two process characteristics—degree of mediation and degree of collaboration—to show how IT may be applied to improve process performance by altering these process characteristics. Based on the framework, guidelines are provided for selecting strategic paths in reengineering specific processes.

On the fracture of solids characterized by one or two parameters: Theory and practice

Abstract: Based on the asymptotic stress fields including higher order terms at the crack tip of a non-linear material, conditions under which single or double parameter controlled onset of fracture initiation occur are discussed. A set of experimental data under cleavage fracture was analysed. It is shown that under Mode I plane strain conditions two parameters J and A2 can be utilized to predict the onset of fracture with J setting the loading level and A2 relating to the constraint. Theoretical meanings of fracture toughness values corresponding to conditions of small scale yielding and the HRR stress distribution are discussed. A procedure of applying this concept to the evaluation of flawed structures is outlined.

Computer program for the analysis of mutational spectra: application to p53 mutations

Abstract: Mutations in the p53 oncogene are extremely common in human cancers, and environmental exposure to mutagenic agents may play a role in the frequency and nature of the mutations. Differences in the patterns of p53 mutations have been observed for different tumor types. It is not trivial to determine if the differences observed in two mutational spectra are statistically significant. To this end, we present a computer program for comparison of two mutational spectra. The program runs on IBM-compatible personal computers and is freely available. The input for the program is a text file containing the number and nature of mutations observed in the two spectra. The output of the program is a P value, which indicates the probability that the two spectra are drawn from the same population. To demonstrate the program, the mutational spectra of single base substitutions in the p53 gene are compared in (i) bladder cancers from smokers and non-smokers, (ii) small-cell lung cancers, non-small-cell lung cancers and colon cancers and (iii) hepatocellular carcinomas from high- and low-aflatoxin exposure groups. p53 mutations differ in several important aspects from a typical mutational spectra experiment, where a homogeneous population of cells is treated with a specific mutagen and mutations at a specific locus are recovered by phenotypic selection. The means by which p53 mutations are recognized is by the appearance of a cancer, and this phenotype is very complex and varied.

Fourier transform raman spectroscopy of synthetic and biological calcium phosphates

Abstract: Fourier-transform (FT) Raman spectroscopy was used to characterize the organic and mineral components of biological and synthetic calcium phosphate minerals. Raman spectroscopy provides information on biological minerals that is complimentary to more widely used infrared methodologies as some infrared-inactive vibrational modes are Raman-active. The application of FT-Raman technology has, for the first time, enabled the problems of high sample fluorescence and low signal-to-noise that are inherent in calcified tissues to be overcome. Raman spectra of calcium phosphates are dominated by a very strong band near 960 cm−1 that arises from the symmetric stretching mode $$\left( {{\mathbf{\rlap{--} v}}_{\text{1}} } \right)$$ of the phosphate group. Other Raman-active phosphate vibrational bands are seen at approximately 1075 $$\left( {{\mathbf{\rlap{--} v}}_{\text{3}} } \right)$$ , 590 $$\left( {{\mathbf{\rlap{--} v}}_{\text{4}} } \right)$$ , and 435 cm−1 $$\left( {{\mathbf{\rlap{--} v}}_{\text{2}} } \right)$$ . Minerals containing acidic phosphate groups show additional vibrational modes. The different calcium phosphate mineral phases can be distinguished from one another by the relative positions and shapes of these bands in the Raman spectra. FT-Raman spectra of nascent, nonmineralized matrix vesicles (MV) show a distinct absence of the phosphate $${\mathbf{\rlap{--} v}}_{\text{1}}$$ band even though these structures are rich in calcium and phosphate. Similar results were seen with milk casein and synthetic Ca-phosphatidyl-serine-PO4 complexes. Hence, the phosphate and/or acidic phosphate ions in these noncrystalline biological calcium phosphates is in a molecular environment that differs from that in synthetic amorphous calcium phosphate. In MV, the first distinct mineral phase to form contained acidic phosphate bands similar to those seen in octacalcium phosphate. The mineral phase present in fully mineralized MV was much more apatitic, resembling that found in bones and teeth. These findings are consistent with formation of an OCP-like precursor during MV mineral formation that subsequently hydrolyzes to form hydroxyapatite.

Chemical identity and ecological implications of a waterborne, larval settlement cue

Abstract: Planktonic oyster larvae (Crassostreu virginica) respond behaviorally to waterborne chemical cues and rapidly settle on substratum. “Settlement” is defined here as attachment of the larval foot to the substrate. Although a topic of considerable research for the past 50 yr, the identity of these cues remains unresolved. We provide four lines of experimental evidence all pointing to the singular identity of these substances. First, molecular-weight fractionations of seawater used to bathe adult oysters (with intact biofilms) were bioassayed, indicating the presence of waterborne settlement inducers between 500 and 1,000 Da. The inducers were degraded by proteases but not by carbohydrases or by lipase. Of several proteases we applied, only those cleaving basic amino acids (lysine and arginine) from the C-terminal and arginase (an enzyme condensing arginine at the C-terminal to ornithine) eliminated settlement-inducing activity. Second, trypsin hydrolysates of casein were significantly more effective in causing larval settlement than products of either acid or pronase hydrolysis of this protein. Third, a tri-peptide having arginine at the C-terminal, glycyl-glycyl+arginine (hereafter referred to as GGR), evoked settlement at a concentration as low as lo-lo M. Dose-response curves for GGR and for the active fraction (500-1,000 Da) of oyster bath water were essentially identical. Fourth, tests of 21 free amino acids identified only lysine and arginine as settlement cues. Larval settlers were far more sensitive to arginine than lysine but significantly less sensitive to arginine than to peptides with arginine at the C-terminal. Our combined results are all consistent in identifying low-molecular-weight peptides with arginine at the C-terminal as the natural, water-soluble cues inducing oyster settlement.

Lexical and message-level sentence context effects on fixation times in reading.

Abstract: Readers' eye movements were recorded as they read an unambiguous noun in a sentence context. In Experiment 1, fixation durations on a target noun were shorter when it was embedded in context containing a subject noun and a verb that were weakly related to the target than when either content word was replaced with a more neutral word. These results were not affected by changes in the syntactic relations between the content words. In Experiment 2, the semantic relations between the message-level representation of the sentence and the target word were altered whereas the lexical content was held constant. Fixation time on the target word was shorter when the context was semantically related to the target word than when it was unrelated. Intralexical priming effects between the subject noun and the verb were also observed. The results suggest that both lexical and message-level representations can influence the access of an individual lexical item in a sentence context.

Modulation of cardiac myocyte phenotype in vitro by the composition and orientation of the extracellular matrix.

Abstract: Cellular phenotype is the result of a dynamic interaction between a cell's intrinsic genetic program and the morphogenetic signals that serve to modulate the extent to which that program is expressed In the present study we have examined how morphogenetic information might be stored in the extracellular matrix (ECM) and communicated to the neonatal heart cell (NHC) by the cardiac alpha 1 beta 1 integrin molecule A thin film of type I collagen (T1C) was prepared with a defined orientation This was achieved by applying T1C to the peripheral edge of a 100 mm culture dish The T1C was then drawn across the surface of the dish in a continuous stroke with a sterile cell scraper and allowed to polymerize When NHCs were cultured on this substrate, they spread, as a population, along a common axis in parallel with the gel lattice and expressed an in vivo-like phenotype Individual NHCs displayed an elongated, rod-like shape and disclosed parallel arrays of myofibrils These phenotypic characteristics were maintained for at least 4 weeks in primary culture The evolution of this tissue-like organizational pattern was dependent upon specific interactions between the NHCs and the collagen-based matrix that were mediated by the cardiac alpha 1 beta 1 integrin complex This conclusion was supported by a variety of experimental results Altering the tertiary structure of the matrix or blocking the extracellular domains of either the cardiac alpha 1 or beta 1 integrin chain inhibited the expression of the tissue-like pattern of organization Neither cell-to-cell contact or contractile function were necessary to induce the formation of the rod-like cell shape However, beating activity was necessary for the assembly of a well-differentiated myofibrillar apparatus These data suggest that the cardiac alpha 1 beta 1 integrin complex serves to detect and transduce phenotypic information stored within the tertiary structure of the surrounding matrix

Primary care, specialty care, and life chances

Abstract: The relationship between the availability of primary care and specialty care and certain life chance indicators such as mortality rates and life expectancy is analyzed using the multiple regression procedure. Dependent variables are life chance indicators; independent variables were selected based on Starfield's and Blum's health determinant models and include socioeconomic environment, lifestyles, demographics, and medical care. The author also examines the rankings of states in terms of these indicators, using Spearman's rho coefficient. Among the medical care variables, primary care is by far the most significant variable related to better health status, correlating with lower overall mortality, lower death rates due to diseases of the heart and cancer, longer life expectancy, lower neonatal death rate, and lower low birth weight. In contrast, the number of specialty physicians is positively and significantly related to total mortality, deaths due to heart diseases and cancer, shorter life expectancy, higher neonatal mortality, and higher low birth weight. From a policy perspective, a likely implication is to reorient the medical profession from its current expensive, clinically based, treatment-focused practice to a more cost-effective, prevention-oriented primary care system.

Cross-cultural research in advertising: An assessment of methodologies

Abstract: The volume of scholarly work in cross-cultural advertising has been increasing in recent years. This study examines empirical studies in this area from a methodological perspective. Cross-cultural research designs should include many critical facets that do not surface in studies involving single cultures. These facets are discussed within the context of cross-cultural advertising literature. It is apparent from this review that a sharper focus on cross-cultural research tools and considerations can strengthen studies of advertising, lead to more robust results, and increase validity and reliability. Both students and practitioners need meaningful and generalizable findings that will emerge only when strict methodological considerations are adhered to.

Black and white females' perceptions of ideal body size and social norms.

Abstract: Different cultural norms and standards for appropriate female body size might contribute to the disparity in obesity rates between black and white adult females (46.0% and 24.6% respectively). The purpose of this study was to measure adolescents' perceptions of ideal size and social norms regarding female body size as well as adolescents' perceptions of significant others' evaluation and expectations of the adolescents' body size. Subjects included 437 adolescent girls (247 white and 190 black) aged 13 to 19 (x = 14.9, SD = .979) from six randomly selected public schools. The subjects, heights and weights were measured. Responses to a body image questionnaire and a series of nine female body drawings (arranged ordinally, 1 to 9, from thinnest to heaviest) were analyzed using the General Linear Model and Logistic Regression. The female body size considered ideal by black females was significantly larger than the size selected as ideal by white females (x = 3.47 and x = 3.13 respectively, p < 0.001). Black females were two times more likely than white females to describe themselves as thinner than other girls their age (O.R. = 2.01, 95% C.I. 1.34, 3.01) and seven times as likely to say that they were not overweight (O.R. = 7.08, 95% C.I. 3.72, 13.45). White females wanted to be a smaller size than they currently were and felt encouraged by significant others to lose weight or reduce their size. Black females did not indicate as great a desire as whites to be smaller and they tended to feel that their size was considered satisfactory by significant others. Only subjects from the low SES group perceived that significant others wanted them to gain weight. The differences between black and white subjects' beliefs and perceptions about body size norms may explain, in part, why heavier body weights persist in some cultural groups.