Showing papers by "Clemson University published in 2002"

A draft sequence of the rice genome (Oryza sativa L. ssp indica)

Abstract: We have produced a draft sequence of the rice genome for the most widely cultivated subspecies in China, Oryza sativa L. ssp. indica, by whole-genome shotgun sequencing. The genome was 466 megabases in size, with an estimated 46,022 to 55,615 genes. Functional coverage in the assembled sequences was 92.0%. About 42.2% of the genome was in exact 20-nucleotide oligomer repeats, and most of the transposons were in the intergenic regions between genes. Although 80.6% of predicted Arabidopsis thaliana genes had a homolog in rice, only 49.4% of predicted rice genes had a homolog in A. thaliana. The large proportion of rice genes with no recognizable homologs is due to a gradient in the GC-content of rice coding sequences.

A second-generation reactive empirical bond order (REBO) potential energy expression for hydrocarbons

Abstract: A second-generation potential energy function for solid carbon and hydrocarbon molecules that is based on an empirical bond order formalism is presented. This potential allows for covalent bond breaking and forming with associated changes in atomic hybridization within a classical potential, producing a powerful method for modelling complex chemistry in large many-atom systems. This revised potential contains improved analytic functions and an extended database relative to an earlier version (Brenner D W 1990 Phys. Rev. B 42 9458). These lead to a significantly better description of bond energies, lengths, and force constants for hydrocarbon molecules, as well as elastic properties, interstitial defect energies, and surface energies for diamond.

Functionalized Carbon Nanotubes: Properties and Applications

Abstract: Carbon nanotubes can be functionalized via amidation and esterification of the nanotube-bound carboxylic acids. The solubility of these functionalized carbon nanotubes makes it possible to characterize and study the properties of carbon nanotubes using solution-based techniques. Representative results concerning the solubility, dispersion, defunctionalization, and optical properties of the functionalized carbon nanotubes are presented. Several examples for the use of functionalized carbon nanotubes in the fabrication of polymeric carbon nanocomposites, the probing of nanotube-molecule interactions, and the conjugation with biological species are highlighted and discussed.

A breadth-first survey of eye-tracking applications

Abstract: Eye-tracking applications are surveyed in a breadth-first manner, reporting on work from the following domains: neuroscience, psychology, industrial engineering and human factors, marketing/advertising, and computer science. Following a review of traditionally diagnostic uses, emphasis is placed on interactive applications, differentiating between selective and gaze-contingent approaches.

An empirical examination of individual traits as antecedents to computer anxiety and computer self-efficacy

Abstract: To better understand how individual differences influence the use of information technology (IT), this study models and tests relationships among dynamic, IT-specific individual differences (i.e., computer self-efficacy and computer anxiety), stable, situation-specific traits (i.e., personal innovativeness in IT) and stable, broad traits (i.e., trait anxiety and negative affectivity). When compared to broad traits, the model suggests that situation-specific traits exert a more pervasive influence on IT situation-specific individual differences. Further, the model suggests that computer anxiety mediates the influence of situation-specific traits (i.e., personal innovativeness) on computer self-efficacy. Results provide support for many of the hypothesized relationships. From a theoretical perspective, the findings help to further our understanding of the nomological network among individual differences that lead to computer self-efficacy. From a practical perspective, the findings may help IT managers design training programs that more effectively increase the computer self-efficacy of users with different dispositional characteristics.

Synthesis and Characterization of Truncated Triangular Silver Nanoplates

Abstract: Truncated triangular silver nanoplates have been synthesized in large quantities using a solution phase method in the presence of cetyltrimethylammonium bromide micelles. The obtained particles have an average edge size of 68 nm, thickness of 24 nm, and the degree of truncation of 0.35. They are single crystals, with a (111) lattice plane as the basal plane. The aqueous solution of these particles displays a clear red color due to a strong in-plane dipole plasmon resonance peaked at 552 nm. These particles can self-assemble into chainlike nanostructures through either partial or close stacking of neighborhood nanoplates.

AGTR2 mutations in X-linked mental retardation.

Abstract: Two angiotensin II (Ang II)-specific receptors, AGTR1 and AGTR2, are expressed in the mammalian brain. Ang II actions on blood pressure regulation, water electrolyte balance, and hormone secretion are primarily mediated by AGTR1. The function of AGTR2 remains unclear. Here, we show that expression of the AGTR2 gene was absent in a female patient with mental retardation (MR) who had a balanced X;7 chromosomal translocation. Additionally, 8 of 590 unrelated male patients with MR were found to have sequence changes in the AGTR2 gene, including one frameshift and three missense mutations. These findings indicate a role for AGTR2 in brain development and cognitive function.

Does Corporate Diversification Destroy Value

Abstract: We analyze several hundred firms that expand via acquisition and0or increase their number of business segments. The combined market reaction to acquisition announcements is positive but acquiring firm excess values decline after the diversifying event. Much of the excess value reduction occurs because our sample firms acquire already discounted business units, and not because diversifying destroys value. This implies that the standard assumption that conglomerate divisions can be benchmarked to typical stand-alone f irms should be carefully reconsidered. We also show that excess value does not decline when firms increase their number of business segments because of pure reporting changes. DOES CORPORATE DIVERSIF ICATION destroy value? Several recent papers attempt to answer this question by comparing the market value of firms that operate multiple lines of business to the value of a portfolio of stand-alone firms operating in the same industries as the conglomerate’s divisions. Lang and Stulz ~1994! use this approach and find that multisegment firms have low values of Tobin’s q compared to stand-alone firms. Similarly, Berger and Ofek ~1995! find that U.S. conglomerates are priced at a mean discount of about 15 percent. Lins and Servaes ~1999! find similar discounts in Japan and the United Kingdom. Indeed, based on the Berger and Ofek methodology, diversified firms with valuation discounts had aggregate value losses of $800 billion in 1995. The magnitude of the value loss suggests that operating the divisions of conglomerates as stand-alone firms would create significant value. In this paper, we provide new evidence on whether the act of corporate diversification destroys value, or whether the divisions that make up conglomerates would trade at a discount, even if they operated as standalone firms.

An Examination of the Construct of Perceived Value for the Prediction of Golf Travelers’ Intentions to Revisit

Abstract: The construct of perceived value has been identified in the marketing literature as one of the most important measures for gaining competitive edge and has been argued to be the most important indicator of repurchase intentions. Yet, in the field of tourism, repurchase intentions and consumer loyalty are often predicted solely by measures of consumer satisfaction and/or service quality. One market in need of repurchase intention research is the golf traveler market. Thus, the purpose of this study was to investigate the measurement and utilization of the construct of golf travelers’ perceived value. Results suggest that current measures of perceived value may be inappropriate and do not capture the construct of perceived value of a service. These findings indicate that theoretical development of perceived value is in need of further research and understanding. Managerial and theoretical implications are discussed.

Partial Adjustment to Public Information and IPO Underpricing

Abstract: We examine the extent to which offer prices reflect public information for 3,325 IPOs over the period 1990–1999. We focus primarily on four variables: share overhang, file range amendments, venture capital backing, and previous issue underpricing. We show that 35%–50% of the variation in IPO underpricing can be predicted using public information known before the offer date and therefore conclude that IPO offer prices underadjust to widely available public information to a much greater extent than previously documented.

Attaching Proteins to Carbon Nanotubes via Diimide-Activated Amidation

Abstract: Carbon nanotubes are functionalized by bovine serum albumin (BSA) proteins via diimide-activated amidation under ambient conditions. The nanotube-BSA conjugates thus obtained are highly water-soluble, forming dark-colored aqueous solutions. Results from characterizations using atomic force microscopy (AFM), thermal gravimetric analysis, Raman, and gel electrophoresis show that the conjugate samples indeed contain both carbon nanotubes and BSA proteins and that the protein species are intimately associated with the nanotubes. Bioactivities of the nanotube-bound proteins are evaluated using the total protein micro-determination assay (the modified Lowry procedure). The results show that the overwhelming majority (∼90%) of the protein species in the nanotube-BSA conjugates remain bioactive.

Controlling Information Systems Development Projects: The View from the Client

Abstract: Increasingly, business clients are actively leading information systems (IS) projects, often in collaboration with IS professionals, and they are exercising a greater degree of project control. Control is defined as all attempts to motivate individuals to achieve desired objectives, and it can be exercised via formal and informal modes. Much of the previous research investigating the choice of control mode has focused on direct reporting relationships between IS project leaders and their superiors in a hierarchical setting. However, the client-IS relationships may take on a variety of forms, including both hierarchical and lateral settings. Moreover, prior research has found that the knowledge of the systems development process is a key antecedent of control, yet clients are unlikely to be as knowledgeable as IS professionals about this process. It is therefore unclear whether prior findings will generalize to the client-IS pair, and the goal of this research is to examine the exercise of control across this relationship. Data were gathered from a questionnaire survey of 69 pairs of clients and IS project leaders. The results are largely consistent with prior research on the antecedents offormal control modes, but they shed new insight on the choice ofinformal control modes.

An integrated physical and genetic map of the rice genome

Abstract: Rice was chosen as a model organism for genome sequencing because of its economic importance, small genome size, and syntenic relationship with other cereal species. We have constructed a bacterial artificial chromosome fingerprint–based physical map of the rice genome to facilitate the whole-genome sequencing of rice. Most of the rice genome (∼90.6%) was anchored genetically by overgo hybridization, DNA gel blot hybridization, and in silico anchoring. Genome sequencing data also were integrated into the rice physical map. Comparison of the genetic and physical maps reveals that recombination is suppressed severely in centromeric regions as well as on the short arms of chromosomes 4 and 10. This integrated high-resolution physical map of the rice genome will greatly facilitate whole-genome sequencing by helping to identify a minimum tiling path of clones to sequence. Furthermore, the physical map will aid map-based cloning of agronomically important genes and will provide an important tool for the comparative analysis of grass genomes.

Effects of hot and cold temperature exposure on performance: a meta-analytic review

Abstract: A meta-analysis to mathematically summarize the effect of hot and cold temperature exposure on performance was completed. The results from 515 effect sizes calculated from 22 original studies suggest that hot and cold temperatures negatively impact performance on a wide range of cognitive-related tasks. More specifically, hot temperatures of 90°F (32.22°C) Web Bulb Globe Temperature Index or above and cold temperatures of 50°F (10°C) or less resulted in the greatest decrement in performance in comparison to neutral temperature conditions (14.88% decrement and 13.91% decrement, respectively). Furthermore, the duration of exposure to the experimental temperature, the duration of exposure to the experimental temperature prior to the task onset, the type of task and the duration of the task had differential effects on performance. The current results indicate that hot and cold temperature exposure have a negative impact on performance and that other variables (e.g., length of exposure to the temperature or task duration) may modify this relationship.

Criterion validity, severity cut scores, and test-retest reliability of the Beck Depression Inventory-II in a university counseling center sample.

Abstract: The criterion validity of the Beck Depression Inventory-II (BDI-II; A. T. Beck, R. A. Steer, & G. K. Brown, 1996) was investigated by pairing blind BDI-II administrations with the major depressive episode portion of the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I; M. B. First, R. L. Spitzer, M. Gibbon, & J. B. W. Williams, 1997) in a sample of 137 students receiving treatment at a university counseling center. Student BDI-II scores correlated strongly (r =.83) with their number of SCID-I depressed mood symptoms. A BDI-II cut score of 16 yielded a sensitivity rate of 84% and a false-positive rate of 18% in identifying depressed mood. Receiver operating characteristic analyses were used to produce cut scores for determining severity of depressed mood. In a second study, a sample of 46 student clients were administered the BDI-II twice, yielding test-retest reliability of.96.

Silver Nanodisks: Synthesis, Characterization, and Self-Assembly

Abstract: A new form of silver nanostructured materials, silver nanodisks, are generated by a solution-phase approach. In this method, truncated triangular silver nanoplates are at first fabricated through s...

CUAVE: A new audio-visual database for multimodal human-computer interface research

Abstract: Multimodal signal processing has become an important topic of research for overcoming certain problems of audio-only speech processing. Audio-visual speech recognition is one area with great potential. Difficulties due to background noise and multiple speakers are significantly reduced by the additional information provided by extra visual features. Despite a few efforts to create databases in this area, none has emerged as a standard for comparison for several possible reasons. This paper seeks to introduce a new audiovisual database that is flexible and fairly comprehensive, yet easily available to researchers on one DVD. The CUAVE database is a speaker-independent corpus of over 7,000 utterances of both connected and isolated digits. It is designed to meet several goals that are discussed in this paper. The most notable are availability of the database, flexibility for use of the audio-visual data, and realistic considerations in the recordings (such as speaker movement). Another important focus of the database is the inclusion of pairs of simultaneous speakers, the first documented database of this kind. The overall goal of this project is to facilitate more widespread audio-visual research through an easily available database. For information on obtaining CUAVE, please visit our webpage (http://ece.clemson.edu/speech).

Contribution of inbreeding to extinction risk in threatened species

Abstract: Wild populations face threats both from deterministic factors, e.g., habitat loss, overexploitation, pollution, and introduced species, and from stochastic events of a demographic, genetic, and environmental nature, including catastrophes. Inbreeding reduces reproductive fitness in naturally outbreeding species, but its role in extinctions of wild populations is controversial. To evaluate critically the role of inbreeding in extinction, we conducted realistic population viability analyses of 20 threatened species, with and without inbreeding depression, using initial population sizes of 50, 250, and 1000. Inbreeding markedly decreased median times to extinction by 28.5, 30.5, and 25% for initial populations of 50, 250, and 1000, respectively, and the impacts were similar across major taxa. The major variable explaining differences among species was initial population growth rate, whereas the impact of inbreeding was least in species with negative growth rates. These results demonstrate that the prospects for survival of threatened species will usually be seriously overestimated if genetic factors are disregarded, and that inappropriate recovery plans may be instituted if inbreeding depression is ignored.

Poly(Vinyl Pyridine) as a Universal Surface Modifier for Immobilization of Nanoparticles

Abstract: Metal, metal oxide, and plastic surfaces were modified with poly(vinylpyridine) using adsorption, spin-coating, and dip-coating techniques and various metal, semiconductor, and dielectric nanoparticles were subsequently attached. Prior to the modification, the substrates were treated with glow discharge plasma for cleaning purposes and to introduce surface functional groups that are capable of interaction with the polymer. UV−vis absorption spectroscopy, atomic force, and electron scanning microscopies were used to characterize polymer layers and layers of immobilized nanoparticles. The surface modification with poly(vinylpyridine) via adsorption technique is suggested as a simple, effective, and highly versatile method for the preparation of single, mixed, and multilayered assemblies of various nanoparticles on different substrates.

A Multiple–Indicator Approach to Municipal Service Evaluation: Correlating Performance Measurement and Citizen Satisfaction across Jurisdictions

Abstract: Early work on municipal service–quality assessment recommended multiple measures of performance from both providers and users. Citizen satisfaction surveys have rivaled their more quantitative counterpart, administrative performance measures, in adoption, but the implication of survey results for action is not well understood by managers or scholars. To achieve meaningfully integrated multiple measures of service quality, we need to explore the dimensions of citizen satisfaction and review patterns of satisfaction across localities. We also need to understand the relationship between administrative performance measures and citizen perceptions. This cross–sectional analysis of municipal citizen satisfaction and performance benchmark data suggests that citizen satisfaction survey results are useful to managers in conjunction with performance–measurement programs as part of a multiple–indicator approach to evaluating municipal service quality. However, understanding citizen perceptions requires a different perspective than that applied to administrative service performance measurement.

Environmental Socialization Quantitative Tests of the Childhood Play Hypothesis

Abstract: Two studies with adolescent youth (N = 1,376, N = 450) help clarify the relationship between childhood play experiences in wild environments and later environmental preferences in the life domains of work, leisure, and school. Respondents reporting having played in wild environments had more positive perceptions of natural environments, outdoor recreation activities, and future indoor/outdoor occupational environments. No significant differences were found for preferences for environmental sciences activities conducted in schools. Results suggest that childhood play in wildland environments is related to environmental competencies and preferences but not necessarily an intellectual interest in environmental sciences or environmentalism.

Sonication-Assisted Functionalization and Solubilization of Carbon Nanotubes

Abstract: Carbon nanotubes were solubilized via functionalization with poly(propionylethylenimine-co-ethylenimine). The diimide-activated amidation reaction for the functionalization was found to be signific...

Temperature dependence of radial breathing mode Raman frequency of single-walled carbon nanotubes

Abstract: Recent high-temperature studies of Raman-active modes in single-walled carbon nanotube (SWNT) bundles report a softening of the radial and tangential band frequencies with increasing sample temperature. A few speculations have been proposed in the past to explain the origin of these frequency downshifts. In the present study, based on experimental data and the results of molecular dynamics simulations, we estimate the contributions from three factors that may be responsible for the observed temperature dependence of the radial breathing mode frequency $[{\ensuremath{\omega}}_{\mathrm{RBM}}(T)].$ These factors include thermal expansion of individual SWNTs in the radial direction, softening of the C-C (intratubular) bonds, and softening of the van der Waals intertubular interactions in SWNT bundles. Based on our analysis, we find that the first factor plays a minor role due to the very small value of the radial thermal expansion coefficient of SWNTs. On the contrary, the temperature-induced softening of the intra- and intertubular bonds contributes significantly to the temperature-dependent shift of ${\ensuremath{\omega}}_{\mathrm{RBM}}(T).$ For nanotubes with diameters $(d)g~1.34\mathrm{nm},$ the contribution due to the radial thermal expansion is \ensuremath{\leqslant}4% over the temperature range used in this study. Interestingly, this contribution increases to \ensuremath{\geqslant}10% in the case of nanotubes having $dl~0.89\mathrm{nm}$ due to the relatively larger curvature of these nanotubes. The contributions from the softening of the intra- and intertubular bonds are approximately equal. These two factors together contribute a total of about \ensuremath{\sim}95% and 90%, respectively, for SWNTs having $dg~1.34\mathrm{nm}$ and \ensuremath{\leqslant}0.89 nm.

Forecasting the NYSE composite index with technical analysis, pattern recognizer, neural networks, and genetic algorithm: a case study in romantic decision support

Abstract: The 21st century is seeing technological advances that make it possible to build more robust and sophisticated decision support systems than ever before. But the effectiveness of these systems may be limited if we do not consider more eclectic (or romantic) options. This paper exemplifies the potential that lies in the novel application and combination of methods, in this case to evaluating stock market purchasing opportunities using the "technical analysis" school of stock market prediction. Members of the technical analysis school predict market prices and movements based on the dynamics of market price and volume, rather than on economic fundamentals such as earnings and market share. The results of this paper support the effectiveness of the technical analysis approach through use of the "bull flag" price and volume pattern heuristic. The romantic approach to decision support exemplified in this paper is made possible by the recent development of: (1) high-performance desktop computing, (2) the methods and techniques of machine learning and soft computing, including neural networks and genetic algorithms, and (3) approaches recently developed that combine diverse classification and forecasting systems. The contribution of this paper lies in the novel application and combination of the decision-making methods and in the nature and superior quality of the results achieved.