Showing papers by "University of South Carolina published in 2005"

Anisotropic metal nanoparticles: Synthesis, assembly, and optical applications

Abstract: This feature article highlights work from the authors' laboratories on the synthesis, assembly, reactivity, and optical applications of metallic nanoparticles of nonspherical shape, especially nanorods. The synthesis is a seed-mediated growth procedure, in which metal salts are reduced initially with a strong reducing agent, in water, to produce ∼4 nm seed particles. Subsequent reduction of more metal salt with a weak reducing agent, in the presence of structure-directing additives, leads to the controlled formation of nanorods of specified aspect ratio and can also yield other shapes of nanoparticles (stars, tetrapods, blocks, cubes, etc.). Variations in reaction conditions and crystallographic analysis of gold nanorods have led to insight into the growth mechanism of these materials. Assembly of nanorods can be driven by simple evaporation from solution or by rational design with molecular-scale connectors. Short nanorods appear to be more chemically reactive than long nanorods. Finally, optical applica...

Market Orientation: A Meta-Analytic Review and Assessment of Its Antecedents and Impact on Performance

Abstract: The authors conduct a meta-analysis that aggregates empirical findings from the market orientation literature. First, the study provides a quantitative summary of the bivariate findings regarding the antecedents and the consequences of market orientation. Second, the authors use multivariate analyses of aggregate study effects to identify significant antecedents of market orientation and the process variables that mediate the relationship between market orientation and performance. In addition, using regression analysis, the authors find that the market orientation–performance relationship is stronger in samples of manufacturing firms, in low power-distance and uncertainty-avoidance cultures, and in studies that use subjective measures of performance. The authors also find that the market orientation–performance correlation is stronger for both cost-based and revenue-based performance measures in manufacturing firms than in service firms. On the basis of the findings, the authors conclude with a ...

Service-oriented computing

Abstract: Traditional approaches to software development - the ones embodied in CASE tools and modeling frameworks - are appropriate for building individual software components, but they are not designed to face the challenges of open environments. Service-oriented computing provides a way to create a new architecture that reflects components' trends toward autonomy and heterogeneity. We thus emphasize SOC concepts instead of how to deploy Web services in accord with current standards. To begin the series, we describe the key concepts and abstractions of SOC and the elements of a corresponding engineering methodology.

The Effect of Social Desirability and Social Approval on Self-Reports of Physical Activity

Abstract: The purpose of this investigation was to examine social desirability and social approval as sources of error in three self-reported physical activity assessments using objective measures of physical activity as reference measures. In 1997, women (n = 81) living in Worcester, Massachusetts, completed doubly labeled water measurements and wore an activity monitor for 14 days. They also completed seven interviewer-administered 24-hour physical activity recalls (PARs) and two different self-administered 7-day PARs. Measures of the personality traits "social desirability" and "social approval" were regressed on 1) the difference between physical activity energy expenditure estimated from doubly labeled water and each physical activity assessment instrument and 2) the difference between monitor-derived physical activity duration and each instrument. Social desirability was associated with overreporting of activity, resulting in overestimation of physical activity energy expenditure by 0.65 kcal/kg/day on the second 7-day PAR (95% confidence interval: 0.06, 1.25) and overestimation of activity durations by 4.15-11.30 minutes/day (both 7-day PARs). Social approval was weakly associated with underestimation of physical activity on the 24-hour PAR (-0.15 kcal/kg/day, 95% confidence interval: -0.30, 0.005). Body size was not associated with reporting bias in this study. The authors conclude that social desirability and social approval may influence self-reported physical activity on some survey instruments.

The Role of Relational Information Processes and Technology Use in Customer Relationship Management

Abstract: Drawing on the relationship marketing and market information processing literature streams, the authors conceptualize and measure relational information processes, or organizational routines that are critical for customer relationship management (CRM). The authors examine the key drivers and outcome of relational information processes and the role of technology in implementing CRM using data collected from a diverse sample of firms. The results show that relational information processes play a vital role in enhancing an organization's customer relationship performance. By moderating the influence of relational information processes on customer relationship performance, technology used for CRM performs an important and supportive role. The study provides insights into why the use of CRM technology might not always deliver the expected customer relationship performance outcome.

Self-directed self-assembly of nanoparticle/copolymer mixtures

Abstract: The organization of inorganic nanostructures within self-assembled organic or biological templates is receiving the attention of scientists interested in developing functional hybrid materials. Previous efforts have concentrated on using such scaffolds to spatially arrange nanoscopic elements as a strategy for tailoring the electrical, magnetic or photonic properties of the material. Recent theoretical arguments have suggested that synergistic interactions between self-organizing particles and a self-assembling matrix material can lead to hierarchically ordered structures. Here we show that mixtures of diblock copolymers and either cadmium selenide- or ferritin-based nanoparticles exhibit cooperative, coupled self-assembly on the nanoscale. In thin films, the copolymers assemble into cylindrical domains, which dictate the spatial distribution of the nanoparticles; segregation of the particles to the interfaces mediates interfacial interactions and orients the copolymer domains normal to the surface, even when one of the blocks is strongly attracted to the substrate. Organization of both the polymeric and particulate entities is thus achieved without the use of external fields, opening a simple and general route for fabrication of nanostructured materials with hierarchical order.

Structural and functional characterisation of cardiac fibroblasts

Abstract: Cardiac fibroblasts form one of the largest cell populations, in terms of cell numbers, in the heart They contribute to structural, biochemical, mechanical and electrical properties of the myocardium Nonetheless, they are often disregarded by in vivo and in vitro studies into cardiac function This review summarizes our understanding of fibroblast origin and identity, their structural organization and role in myocardial architecture, as well as functional aspects related to cell signalling and electro-mechanical function in the heart

Tuned Lamb-Wave Excitation and Detection with Piezoelectric Wafer Active Sensors for Structural Health Monitoring

Abstract: The capability of embedded piezoelectric wafer active sensors (PWAS) to excite and detect tuned Lamb waves for structural health monitoring is explored. First, a brief review of Lamb waves theory is presented. Second, the PWAS operating principles and their structural coupling through a thin adhesive layer are analyzed. Then, a model of the Lamb waves tuning mechanism with PWAS transducers is described. The model uses the space domain Fourier transform. The analysis is performed in the wavenumber space. The inverse Fourier transform is used to return into the physical space. The integrals are evaluated with the residues theorem. A general solution is obtained for a generic expression of the interface shear stress distribution. The general solution is reduced to a closed-form expression for the case of ideal bonding which admits a closed-form Fourier transform of the interfacial shear stress. It is shown that the strain wave response varies like sin a, whereas the displacement response varies like sinc a. ...

Developing a Process-Evaluation Plan for Assessing Health Promotion Program Implementation: A How-To Guide

Abstract: Process evaluation is used to monitor and document program implementation and can aid in understanding the relationship between specific program elements and program outcomes. The scope and implementation of process evaluation has grown in complexity as its importance and utility have become more widely recognized. Several practical frameworks and models are available to practitioners to guide the development of a comprehensive evaluation plan, including process evaluation for collaborative community initiatives. However, frameworks for developing a comprehensive process-evaluation plan for targeted programs are less common. Building from previous frameworks, the authors present a comprehensive and systematic approach for developing a process-evaluation plan to assess the implementation of a targeted health promotion intervention. Suggested elements for process-evaluation plans include fidelity, dose (delivered and received), reach, recruitment, and context. The purpose of this article is to describe and illustrate the steps involved in developing a process evaluation plan for any health promotion program.

Food insecurity affects school children's academic performance, weight gain, and social skills

Abstract: Food insecurity has been associated with diverse developmental consequences for U.S. children primarily from cross-sectional studies. We used longitudinal data to investigate how food insecurity over time related to changes in reading and mathematics test performance, weight and BMI, and social skills in children. Data were from the Early Childhood Longitudinal Study-Kindergarten Cohort, a prospective sample of approximately 21,000 nationally representative children entering kindergarten in 1998 and followed through 3rd grade. Food insecurity was measured by parent interview using a modification of the USDA module in which households were classified as food insecure if they reported > or =1 affirmative response in the past year. Households were grouped into 4 categories based on the temporal occurrence of food insecurity in kindergarten and 3rd grade. Children's academic performance, height, and weight were assessed directly. Children's social skills were reported by teachers. Analyses examined the effects of modified food insecurity on changes in child outcomes using lagged, dynamic, and difference (i.e., fixed-effects) models and controlling for child and household contextual variables. In lagged models, food insecurity was predictive of poor developmental trajectories in children before controlling for other variables. Food insecurity thus serves as an important marker for identifying children who fare worse in terms of subsequent development. In all models with controls, food insecurity was associated with outcomes, and associations differed by gender. This study provides the strongest empirical evidence to date that food insecurity is linked to specific developmental consequences for children, and that these consequences may be both nutritional and nonnutritional.

Internal and External Integration for Product Development: The Contingency Effects of Uncertainty, Equivocality, and Platform Strategy

Abstract: Effective product development requires firms to unify internal and external participants. As companies attempt to create this integrated environment, two important questions emerge. Does a high level of internal integration lead to a higher level of external integration? In the context of product development, this study considers whether internal integration in the form of concurrent engineering practices affects the level of external integration as manifested by customer integration, supplier product integration, and supplier process integration. External integration, in turn, may influence competitive capabilities, namely product innovation performance and quality performance. Second, using contingency theory, do certain contextual variables moderate the linkages between integration strategy (external and internal) and performance? Specifically, this study considers whether uncertainty, equivocality, and platform development strategy change the relationships among internal integration, external integration, and competitive capabilities. Data collected from 244 manufacturing firms across several industries were used to test these research questions. The results indicate that both internal and external integration positively influence product innovation and quality and ultimately, profitability. With respect to contingency effects, the results indicate that equivocality moderates the relationships between integration and performance.

Bayesian Survival Analysis

Abstract: Great strides in the analysis of survival data using Bayesian methods have been made in the past ten years due to advances in Bayesian computation and the feasibility of such methods. In this chapter, we review Bayesian advances in survival analysis and discuss the various semiparametric modeling techniques that are now commonly used. We review parametric and semiparametric approaches to Bayesian survival analysis, with a focus on proportional hazards models. Reference to other types of models are also given. Keywords: beta process; Cox model; Dirichlet process; gamma process; Gibbs sampling; piecewise exponential model; Weibull model

Surface-Enhanced Raman Spectroscopy of Self-Assembled Monolayers: Sandwich Architecture and Nanoparticle Shape Dependence

Abstract: Surface enhanced Raman scattering (SERS) spectra of 4-mercaptobenzoic acid (4-MBA) self-assembled monolayers (SAMs) on gold substrates is presented for SAMs onto which gold nanoparticles of various shapes have been electrostatically immobilized. SERS spectra of 4-MBA SAMs are enhanced in the presence of immobilized gold nanocrystals by a factor of 107−109 relative to 4-MBA in solution. Large enhancement factors are a likely result of plasmon coupling between the nanoparticles (localized surface plasmon) and the smooth gold substrate (surface plasmon polariton), creating large localized electromagnetic fields at their interface, where 4-MBA molecules reside in this sandwich architecture. Moreover, enhancement factors depend on nanoparticle shape and vary by a factor of 102. This SERS geometry offers large surface enhancements for molecules adsorbed onto planar substrates and could be quite useful for determining chemical information for poor Raman scatterers from assays on 2-D substrates.

Corporate Governance and Bank Performance: A Joint Analysis of the Static, Selection, and Dynamic Effects of Domestic, Foreign, and State Ownership

Abstract: We jointly analyze the static, selection, and dynamic effects of domestic, foreign, and state ownership on bank performance. We argue that it is important to include indicators of all the relevant governance effects in the same model. "Nonrobustness" checks (which purposely exclude some indicators) support this argument. Using data from Argentina in the 1990s, our strongest and most robust results concern state ownership. State-owned banks have poor long-term performance (static effect), those undergoing privatization had particularly poor performance beforehand (selection effect), and these banks dramatically improved following privatization (dynamic effect). However, much of the measured improvement is likely due to placing nonperforming loans into residual entities, leaving "good" privatized banks.

Treatment of acute midshaft clavicle fractures: Systematic review of 2144 fractures. On behalf of the Evidence-Based Orthopaedic Trauma Working Group

Abstract: Background:Fractures of the clavicle were reported to represent 2.6% of all fractures1 with an overall incidence of 64 per 100,000 per year (1987, Malmo, Sweden).2 Midshaft fractures account for approximately 69% to 81% of all clavicle fractures.1-4 Treatment options for acute midshaft clavicle frac

False Discovery Rate–Adjusted Multiple Confidence Intervals for Selected Parameters

Abstract: Often in applied research, confidence intervals (CIs) are constructed or reported only for parameters selected after viewing the data. We show that such selected intervals fail to provide the assumed coverage probability. By generalizing the false discovery rate (FDR) approach from multiple testing to selected multiple CIs, we suggest the false coverage-statement rate (FCR) as a measure of interval coverage following selection. A general procedure is then introduced, offering FCR control at level q under any selection rule. The procedure constructs a marginal CI for each selected parameter, but instead of the confidence level 1 − q being used marginally, q is divided by the number of parameters considered and multiplied by the number selected. If we further use the FDR controlling testing procedure of Benjamini and Hochberg for selecting the parameters, the newly suggested procedure offers CIs that are dual to the testing procedure and are shown to be optimal in the independent case. Under the positive re...

What Makes the Difference? A Practical Analysis of Research on the Effectiveness of Distance Education

Abstract: This article reports findings of a meta-analytical study of research on distance education. The purpose of this study was to identify factors that affect the effectiveness of distance education. The results show that although the aggregated data of available studies show no significant difference in outcomes between distance education and face-to-face education as previous research reviews suggest, there is remarkable difference across the studies. Further examination of the difference reveals that distance education programs, just like traditional education programs, vary a great deal in their outcomes, and the outcome of distance education is associated with a number of pedagogical and technological factors. This study led to some important data-driven suggestions for and about distance education.

Molecular Mechanisms of Flower Development: An Armchair Guide

Abstract: An afternoon stroll through an English garden reveals the breathtaking beauty and enormous diversity of flowering plants. The extreme variation of flower morphologies, combined with the relative simplicity of floral structures and the wealth of floral mutants available, has made the flower an excellent model for studying developmental cell-fate specification, morphogenesis and tissue patterning. Recent molecular genetic studies have begun to reveal the transcriptional regulatory cascades that control early patterning events during flower formation, the dynamics of the gene-regulatory interactions, and the complex combinatorial mechanisms that create a distinct final floral architecture and form.

Fine-tuning the shape of gold nanorods

Abstract: Gold nanorods prepared by a seed-mediated growth approach use ∼4-nm gold nanospheres as the seeds and subsequent reduction of metal salt with a weak reducing agent (ascorbic acid) in the presence of a directing surfactant to produce nanorods. If insufficient ascorbic acid is added in the growth step, then metal salt remains. Additional input of ascorbic acid preferentially deposits more metal at the ends of the nanorods, to yield “dogbone”-like structures. Surprisingly, heat treatment of the unpurified gold nanorods (prepared with an insufficient amount of ascorbic acid) yielded fatter gold nanorods; the oxidation product of ascorbic acid appears to act as a reductant at higher temperature. These modified shapes of the gold nanorods directly influence their optical properties.

Enjoyment mediates effects of a school-based physical-activity intervention.

Abstract: Purpose:The study evaluated whether targeted changes in factors influencing enjoyment of physical education (PE), physical activity enjoyment, and self-efficacy beliefs about participating in physical activity mediated the effect of the Lifestyle Education for Activity Program (LEAP) interve

BIOPHYSICS, PHYSIOLOGICAL ECOLOGY, AND CLIMATE CHANGE: Does Mechanism Matter?

Abstract: Recent meta-analyses have shown that the effects of climate change are detectable and significant in their magnitude, but these studies have emphasized the utility of looking for large-scale patterns without necessarily understanding the mechanisms underlying these changes. Using a series of case studies, we explore the potential pitfalls when one fails to incorporate aspects of physiological performance when predicting the consequences of climate change on biotic communities. We argue that by considering the mechanistic details of physiological performance within the context of biophysical ecology (engineering methods of heat, mass and momentum exchange applied to biological systems), such approaches will be better poised to predict where and when the impacts of climate change will most likely occur.

Mechanisms for the Inhibition of DNA Methyltransferases by Tea Catechins and Bioflavonoids

Abstract: In the present investigation, we studied the modulating effects of several tea catechins and bioflavonoids on DNA methylation catalyzed by prokaryotic SssI DNA methyltransferase (DNMT) and human DNMT1. We found that each of the tea polyphenols [catechin, epicatechin, and (-)-epigallocatechin-3-O-gallate (EGCG)] and bioflavonoids (quercetin, fisetin, and myricetin) inhibited SssI DNMT- and DNMT1-mediated DNA methylation in a concentration-dependent manner. The IC(50) values for catechin, epicatechin, and various flavonoids ranged from 1.0 to 8.4 microM, but EGCG was a more potent inhibitor, with IC(50) values ranging from 0.21 to 0.47 microM. When epicatechin was used as a model inhibitor, kinetic analyses showed that this catechol-containing dietary polyphenol inhibited enzymatic DNA methylation in vitro largely by increasing the formation of S-adenosyl-L-homocysteine (a potent noncompetitive inhibitor of DNMTs) during the catechol-O-methyltransferase-mediated O-methylation of this dietary catechol. In comparison, the strong inhibitory effect of EGCG on DNMT-mediated DNA methylation was independent of its own methylation and was largely due to its direct inhibition of the DNMTs. This inhibition is strongly enhanced by Mg(2+). Computational modeling studies showed that the gallic acid moiety of EGCG plays a crucial role in its high-affinity, direct inhibitory interaction with the catalytic site of the human DNMT1, and its binding with the enzyme is stabilized by Mg(2+). The modeling data on the precise molecular mode of EGCG's inhibitory interaction with human DNMT1 agrees perfectly with our experimental finding.

Quantum Paradoxes: Quantum Theory for the Perplexed

Abstract: 1 The Uses of Paradox.1.1 Paradox in Physics.1.2 Errors.1.3 Gaps.1.4 Contradictions.1.5 Overview of the Book.References.2 How to Weigh a Quantum.2.1 Why does the Color of the Light Change?2.2 Quanta.2.3 Uncertainty Relations.2.4 The Clock-in-the-Box Paradox.2.5 From Inconsistency to Incompleteness.References.3 Is Quantum Theory Complete?3.1 The Einstein-Podolsky-Rosen Paradox.3.2 Polarized Photons.3.3 Quantum States and Observables.3.4 Bell's Inequality.3.5 Paradox and Beyond.References.4 Phases and Gauges.4.1 Two Paradoxical Procedures.4.2 Classical and Quantum Phases.4.3 Phase Meets Gauge.4.4 The Aharonov-Bohm Effect.4.5 Quantum Consistency and the Aharonov-Bohm Effect.4.6 Flux Quantization.4.7 Magnetoresistance.4.8 Non-Abelian Phases.References.5 Modular Variables.5.1 A Lattice of Solenoids.5.2 Non-overlapping Wave Packets.5.3 Modular Momentum.5.4 The xmod, pmod Representation.5.5 Intimations of Nonlocality.References.6 Nonlocality and Causality.6.1 Causality and a Piston.6.2 Quantum Effects Without Classical Analogues.6.3 Modular Energy.6.4 Reconciling the Irreconcilable.References.7 Quantum Measurements.7.1 The Velocity Paradox.7.2 A Quantum Measurement Paradigm.7.3 Quantum Measurements and Uncertainty Relations.7.4 Paradox Lost.References.8 Measurement and Compensation.8.1 Paradox Regained.8.2 Compensating Forces.8.3 Quantum Measurements of Noncanonical Observables.8.4 Measuring the Electric Field.8.5 Energy and Time.References.9 Quantum Cats.9.1 Schr odinger's Cat.9.2 A Quantum Catalyst.9.3 Quantum Concatenations.9.4 A Quantum Catalog.References.10 A Quantum Arrow of Time?10.1 A Quantum Card Trick.10.2 Time Reversal.10.3 The Aharonov-Bergmann-Lebowitz Formula.10.4 The Arrow of Time Revisited.10.5 Boundary Conditions on the Universe.References.11 Superselection Rules.11.1 Superselection Rule for Angular Momentum?11.2 T and Spin.11.3 The Wick-Wightman-Wigner Argument.11.4 Everything is Relative.11.5 Superposing Charge States.References.12 Quantum Slow Dance.12.1 A Watched Pot Never Boils.12.2 The Adiabatic Approximation.12.3 Feynman Paths.12.4 Classical Analogues.References.13 Charges and Fluxons.13.1 Hidden Momentum?13.2 Duality of the Aharonov-Bohm Effect.13.3 The Aharonov-Bohm Effect and Berry's Phase.13.4 The Aharonov-Casher Effect.References.14 Quantum Measurements and Relativity.14.1 Collapse and Relativity.14.2 Relativistic Constraints on Measurements.14.3 Nonlocal Measurements.14.4 Which Nonlocal Operators are Measurable?14.5 Measuring a Nonlocal Operator.14.6 Collapse and Relativity Revisited.References.15 How to Observe a Quantum Wave.15.1 Dipole Paradox.15.2 How not to Observe a Quantum Wave.15.3 Protective Measurements.15.4 Galilean Dialogue.15.5 Protective Measurements and Causality.15.6 Towards Quantum Field Theory.References.16 Weak Values.16.1 A Weak Measurement.16.2 A Paradox of Errors.16.3 Pre- and Postselected Ensembles.16.4 Weak Measurements and Weak Values.16.5 A Quantum Shell Game.16.6 The Quantum Walk.16.7 Faster than Light.16.8 Galilean Dialogue.References.17 Weak Values and Entanglement.17.1 Interaction-free Paradox.17.2 A Grin Without a Cat.17.3 Alice and Bob in Wonderland.17.4 Galilean Dialogue.17.5 Complex Weak Values.References.18 The Quantum World.18.1 Weak Measurements and Interference.18.2 From Amplitudes to Probabilities.18.3 The Fate of the Universe.18.4 The Role of h.18.5 Causality and Nonlocality as Axioms.18.6 Causality, Nonlocality and Scaling.18.7 What is the Quantum World?References.Index.

Breaking the School to Prison Pipeline: Identifying School Risk and Protective Factors for Youth Delinquency

Abstract: Academic failure, exclusionary discipline practices, and dropout have been identified as key elements in a "school to prison pipeline." Although a strong body of research exists on the risks for delinquency, few studies have attempted to understand the variables within schools that exacerbate or counteract these risks. We conducted three multimethod studies that examined three school characteristics related to delinquency-academic failure, suspension, and dropout-at the elementary, middle, and high school levels respectively. We compared schools that were high performing with those that were low performing with respect to each of these characteristics. Our results suggest that school-level characteristics can help minimize the risks for youth delinquency. The majority of court-involved youth have experienced academic failure, school exclusion, and dropout. Our findings, in conjunction with those of other researchers, identified school-based policies and practices that may exacerbate or mitigate the risks ...