Showing papers by "University of North Texas published in 2010"

Strategies in the design of nanoparticles for therapeutic applications

Abstract: Engineered nanoparticles have the potential to revolutionize the diagnosis and treatment of many diseases; for example, by allowing the targeted delivery of a drug to particular subsets of cells. However, so far, such nanoparticles have not proved capable of surmounting all of the biological barriers required to achieve this goal. Nevertheless, advances in nanoparticle engineering, as well as advances in understanding the importance of nanoparticle characteristics such as size, shape and surface properties for biological interactions, are creating new opportunities for the development of nanoparticles for therapeutic applications. This Review focuses on recent progress important for the rational design of such nanoparticles and discusses the challenges to realizing the potential of nanoparticles.

T-drive: driving directions based on taxi trajectories

Abstract: GPS-equipped taxis can be regarded as mobile sensors probing traffic flows on road surfaces, and taxi drivers are usually experienced in finding the fastest (quickest) route to a destination based on their knowledge. In this paper, we mine smart driving directions from the historical GPS trajectories of a large number of taxis, and provide a user with the practically fastest route to a given destination at a given departure time. In our approach, we propose a time-dependent landmark graph, where a node (landmark) is a road segment frequently traversed by taxis, to model the intelligence of taxi drivers and the properties of dynamic road networks. Then, a Variance-Entropy-Based Clustering approach is devised to estimate the distribution of travel time between two landmarks in different time slots. Based on this graph, we design a two-stage routing algorithm to compute the practically fastest route. We build our system based on a real-world trajectory dataset generated by over 33,000 taxis in a period of 3 months, and evaluate the system by conducting both synthetic experiments and in-the-field evaluations. As a result, 60-70% of the routes suggested by our method are faster than the competing methods, and 20% of the routes share the same results. On average, 50% of our routes are at least 20% faster than the competing approaches.

Engaging online learners: The impact of Web-based learning technology on college student engagement

Abstract: Widespread use of the Web and other Internet technologies in postsecondary education has exploded in the last 15years. Using a set of items developed by the National Survey of Student Engagement (NSSE), the researchers utilized the hierarchical linear model (HLM) and multiple regressions to investigate the impact of Web-based learning technology on student engagement and self-reported learning outcomes in face-to-face and online learning environments. The results show a general positive relationship between the use the learning technology and student engagement and learning outcomes. We also discuss the possible impact on minority and part-time students as they are more likely to enroll in online courses.

Corporate psychopathy: Talking the walk.

Abstract: There is a very large literature on the important role of psychopathy in the criminal justice system. We know much less about corporate psychopathy and its implications, in large part because of the difficulty in obtaining the active cooperation of business organizations. This has left us with only a few small-sample studies, anecdotes, and speculation. In this study, we had a unique opportunity to examine psychopathy and its correlates in a sample of 203 corporate professionals selected by their companies to participate in management development programs. The correlates included demographic and status variables, as well as in-house 360 degrees assessments and performance ratings. The prevalence of psychopathic traits-as measured by the Psychopathy Checklist-Revised (PCL-R) and a Psychopathy Checklist: Screening Version (PCL: SV) "equivalent"-was higher than that found in community samples. The results of confirmatory factor analysis (CFA) and structural equation modeling (SEM) indicated that the underlying latent structure of psychopathy in our corporate sample was consistent with that model found in community and offender studies. Psychopathy was positively associated with in-house ratings of charisma/presentation style (creativity, good strategic thinking and communication skills) but negatively associated with ratings of responsibility/performance (being a team player, management skills, and overall accomplishments).

Measuring state capacity: Theoretical and empirical implications for the study of civil conflict

Abstract: This article identifies and addresses key conceptual and measurement issues raised by measures of state capacity in studies of civil conflict. First, it reviews competing definitions and operationa...

Testing for Interaction in Binary Logit and Probit Models: Is a Product Term Essential?

Abstract: Political scientists presenting binary dependent variable (BDV) models often hypothesize that variables interact to influence the probability of an event, Pr(Y). The current typical approach to testing such hypotheses is (1) estimate a logit or probit model with a product term, (2) test the hypothesis by determining whether the coefficient for this term is statistically significant, and (3) characterize the nature of any interaction detected by describing how the estimated effect of one variable on Pr(Y) varies with the value of another. This approach makes a statistically significant product term necessary to support the interaction hypothesis. We show that a statistically significant product term is neither necessary nor sufficient for variables to interact meaningfully in influencing Pr(Y). Indeed, even when a logit or probit model contains no product term, the effect of one variable on Pr(Y) may be strongly related to the value of another. We present a strategy for testing for interaction in a BDV model, including guidance on when to include a product term.

Testosterone physiology in resistance exercise and training: the up-stream regulatory elements.

Abstract: Testosterone is one of the most potent naturally secreted androgenic-anabolic hormones, and its biological effects include promotion of muscle growth. In muscle, testosterone stimulates protein synthesis (anabolic effect) and inhibits protein degradation (anti-catabolic effect); combined, these effects account for the promotion of muscle hypertrophy by testosterone. These physiological signals from testosterone are modulated through the interaction of testosterone with the intracellular androgen receptor (AR). Testosterone is important for the desired adaptations to resistance exercise and training; in fact, testosterone is considered the major promoter of muscle growth and subsequent increase in muscle strength in response to resistance training in men. The acute endocrine response to a bout of heavy resistance exercise generally includes increased secretion of various catabolic (breakdown-related) and anabolic (growth-related) hormones including testosterone. The response of testosterone and AR to resistance exercise is largely determined by upper regulatory elements including the acute exercise programme variable domains, sex and age. In general, testosterone concentration is elevated directly following heavy resistance exercise in men. Findings on the testosterone response in women are equivocal with both increases and no changes observed in response to a bout of heavy resistance exercise. Age also significantly affects circulating testosterone concentrations. Until puberty, children do not experience an acute increase in testosterone from a bout of resistance exercise; after puberty some acute increases in testosterone from resistance exercise can be found in boys but not in girls. Aging beyond 35-40 years is associated with a 1-3% decline per year in circulating testosterone concentration in men; this decline eventually results in the condition known as andropause. Similarly, aging results in a reduced acute testosterone response to resistance exercise in men. In women, circulating testosterone concentration also gradually declines until menopause, after which a drastic reduction is found. In summary, testosterone is an important modulator of muscle mass in both men and women and acute increases in testosterone can be induced by resistance exercise. In general, the variables within the acute programme variable domains must be selected such that the resistance exercise session contains high volume and metabolic demand in order to induce an acute testosterone response.

Microelectrode arrays: a physiologically based neurotoxicity testing platform for the 21st century.

Abstract: Microelectrode arrays (MEAs) have been in use over the past decade and a half to study multiple aspects of electrically excitable cells. In particular, MEAs have been applied to explore the pharmacological and toxicological effects of numerous compounds on spontaneous activity of neuronal and cardiac cell networks. The MEA system enables simultaneous extracellular recordings from multiple sites in the network in real time, increasing spatial resolution and thereby providing a robust measure of network activity. The simultaneous gathering of action potential and field potential data over long periods of time allows the monitoring of network functions that arise from the interaction of all cellular mechanisms responsible for spatio-temporal pattern generation. In these functional, dynamic systems, physical, chemical, and pharmacological perturbations are holistically reflected by the tissue responses. Such features make MEA technology well suited for the screening of compounds of interest, and also allow scaling to high throughput systems that can record from multiple, separate cell networks simultaneously in multi-well chips or plates. This article is designed to be useful to newcomers to this technology as well as those who are currently using MEAs in their research. It explains how MEA systems operate, summarizes what systems are available, and provides a discussion of emerging mathematical schemes that can be used for a rapid classification of drug or chemical effects. Current efforts that will expand this technology to an influential, high throughput, electrophysiological approach for reliable determinations of compound toxicity are also described and a comprehensive review of toxicological publications using MEAs is provided as an appendix to this publication. Overall, this article highlights the benefits and promise of MEA technology as a high throughput, rapid screening method for toxicity testing.

Toward an integrated framework for online consumer behavior and decision making process: A review

Abstract: This paper presents a comprehensive review of recent empirical studies dealing with online consumer behavior and decision-making processes. To that end, the paper adapts and extends Engel, Kollat, and Blackwell's (1978) and Engel, Blackwell, and Miniard's (1986) decision-making model as backdrop in the review of the literature. The vast majority of studies examine the link between external factors and one or more components of the decision-making process. The findings of this study show a paucity of research on a number of components of decision making, as well as inconsistencies in the way the online environment is characterized. Finally, the findings show that student samples are prevalent among the studies identified and the research method is biased toward the survey method as opposed to experimentation. Discussion and conclusions are provided, and directions for future research are presented. ©2010 Wiley Periodicals, Inc.

The role of antisociality in the psychopathy construct: comment on Skeem and Cooke (2010).

Abstract: J. Skeem and D. J. Cooke (2010) asserted that Hare and Neumann consider criminality to be an essential component of the psychopathy construct. The assertion, presented in the guise of a debate on the nature of psychopathy, is neither accurate nor consistent with the clinical and empirical literature on psychopathy to which Hare and Neumann have contributed. Broadly defined antisociality, not criminality per se, is considered to be part of the psychopathy construct. Skeem and Cooke also expressed concerns that the popularity of the Psychopathy Checklist-Revised (R. D. Hare, 2003) inhibits the development and use of other instruments, that it has become the construct it measures, that it deviates from its clinical roots, and that it conflates criminality with personality. These and related issues are addressed, and it is suggested that the arguments proffered by Skeem and Cooke are not convincing, nor do they provide clear directions for theory and research.

An Interactive-Voting Based Map Matching Algorithm

Abstract: Matching a raw GPS trajectory to roads on a digital map is often referred to as the Map Matching problem. However, the occurrence of the low-sampling-rate trajectories (e.g. one point per 2 minutes) has brought lots of challenges to existing map matching algorithms. To address this problem, we propose an Interactive Voting-based Map Matching (IVMM) algorithm based on the following three insights: 1) The position context of a GPS point as well as the topological information of road networks, 2) the mutual influence between GPS points (i.e., the matching result of a point references the positions of its neighbors; in turn, when matching its neighbors, the position of this point will also be referenced), and 3) the strength of the mutual influence weighted by the distance between GPS points (i.e., the farther distance is the weaker influence exists). In this approach, we do not only consider the spatial and temporal information of a GPS trajectory but also devise a voting-based strategy to model the weighted mutual influences between GPS points. We evaluate our IVMM algorithm based on a user labeled real trajectory dataset. As a result, the IVMM algorithm outperforms the related method (ST-Matching algorithm).

Epigenetics and transgenerational transfer: A physiological perspective

Abstract: Epigenetics, the transgenerational transfer of phenotypic characters without modification of gene sequence, is a burgeoning area of study in many disciplines of biology. However, the potential impact of this phenomenon on the physiology of animals is not yet broadly appreciated, in part because the phenomenon of epigenetics is not typically part of the design of physiological investigations. Still enigmatic and somewhat ill defined is the relationship between the overarching concept of epigenetics and interesting transgenerational phenomena (e.g. 'maternal/parental effects') that alter the physiological phenotype of subsequent generations. The lingering effect on subsequent generations of an initial environmental disturbance in parent animals can be profound, with genes continuing to be variously silenced or expressed without an associated change in gene sequence for many generations. Known epigenetic mechanisms involved in this phenomenon include chromatin remodeling (DNA methylation and histone modification), RNA-mediated modifications (non-coding RNA and microRNA), as well as other less well studied mechanisms such as self-sustaining loops and structural inheritance. In this review we: (1) discuss how the concepts of epigenetics and maternal effects both overlap with, and are distinct from, each other; (2) analyze examples of existing animal physiological studies based on these concepts; and (3) offer a construct by which to integrate these concepts into the design of future investigations in animal physiology.

Determinants of US consumer mobile shopping services adoption: implications for designing mobile shopping services

Abstract: Purpose – The purpose of this study is to examine critical determinants of US consumers' intentions to use mobile shopping services and to provide implications for retailers and mobile marketers in order to offer mobile shopping services that meet consumers' quality expectations.Design/methodology/approach – A sample of 400 mobile services users drawn from a purchased consumer panel participated in an online survey. The Unified Theory of Acceptance and Use of Technology (UTAUT) model was adapted and incorporated with attitude and hedonic performance expectancy. Two steps of structural equation modeling were used to validate the measurement model and test the hypothesized relationships.Findings – The study found that utilitarian and hedonic performance expectancy, social influence, and facilitating conditions are critical determinants of US consumers' intentions to use mobile shopping services. Effort expectancy is a driving factor affecting utilitarian and hedonic performance expectancy of mobile shopping...

Conformal Fractals: Ergodic Theory Methods

Abstract: Introduction Basic examples and definitions 1. Measure preserving endomorphisms 2. Compact metric spaces 3. Distance expanding maps 4. Thermodynamical formalism 5. Expanding repellers in manifolds and in the Riemann sphere, preliminaries 6. Cantor repellers in the line, Sullivan's scaling function, application in Feigenbaum universality 7. Fractal dimensions 8. Conformal expanding repellers 9. Sullivan's classification of conformal expanding repellers 10. Holomorphic maps with invariant probability measures of positive Lyapunov exponent 11. Conformal measures References Index.

Identification in organizations: The role of self-concept orientations and identification motives

Abstract: We develop an integrative framework that sheds light on managing multiple targets of employee identifications—specifically, coworker, workgroup, and organizational identifications. Drawing from cross-cultural and gender studies, we distinguish between individual tendencies (self-concept orientations) and self-definitions with specific relationships or groups (identifications). We explicate the role of individualist, relationist, and collectivist self-concept orientations, as well as identification motives, on organizationally relevant identifications and conclude with a discussion of the implications for identification in organizations.

Financial Executive Qualifications, Financial Executive Turnover, and Adverse SOX 404 Opinions

Abstract: This study attempts to provide a comprehensive understanding of the interrelationships among chief financial officers’ (CFOs’) professional qualifications, SOX Section 404 internal control weakness, CFOs’ turnover, CFOs’ qualification improvement, and remediation of material weaknesses. We find that firms receiving initial adverse SOX 404 opinions for 2004 have less qualified CFOs. Adverse SOX 404 opinion recipients experience more CFO turnover in 2005, and these firms are more likely to hire CFOs having improved qualifications. Results show that simply hiring a new CFO is not associated with SOX 404 opinion improvement. Opinion improvement requires hiring a better qualified CFO.

Childhood emotional abuse and the attachment system across the life cycle: What theory and research tell us.

Abstract: The purpose of this article is to review the theoretical and empirical literature regarding the normative development of the attachment system from infancy through adulthood, and then discuss deviations from the normal developmental pathways that occur in response to emotionally abusive parenting (e.g., strong rejection, intrusive or controlling, hostile, or frightening behavior). A theoretical model grounded in attachment theory is presented describing the development of maladaptive interaction patterns in adult romantic relationships. The model proposes that early emotional abuse engenders insecure attachment, which impairs emotional regulation, fosters negative views of self and others that support maladaptive coping responses, interferes with social functioning and the capacity for intimate adult attachments, contributes to poor mental health, and consequently shapes the quality of romantic relationships.

Text and Structural Data Mining of Influenza Mentions in Web and Social Media

Abstract: Text and structural data mining of web and social media (WSM) provides a novel disease surveillance resource and can identify online communities for targeted public health communications (PHC) to assure wide dissemination of pertinent information WSM that mention influenza are harvested over a 24-week period, 5 October 2008 to 21 March 2009 Link analysis reveals communities for targeted PHC Text mining is shown to identify trends in flu posts that correlate to real-world influenza-like illness patient report data We also bring to bear a graph-based data mining technique to detect anomalies among flu blogs connected by publisher type, links, and user-tags

A serum protein-based algorithm for the detection of Alzheimer disease.

Abstract: Objective To develop an algorithm that separates patients with Alzheimer disease (AD) from controls. Design Longitudinal case-control study. Setting The Texas Alzheimer's Research Consortium project. Patients We analyzed serum protein–based multiplex biomarker data from 197 patients diagnosed with AD and 203 controls. Main Outcome Measure The total sample was randomized equally into training and test sets and random forest methods were applied to the training set to create a biomarker risk score. Results The biomarker risk score had a sensitivity and specificity of 0.80 and 0.91, respectively, and an area under the curve of 0.91 in detecting AD. When age, sex, education, and APOE status were added to the algorithm, the sensitivity, specificity, and area under the curve were 0.94, 0.84, and 0.95, respectively. Conclusions These initial data suggest that serum protein-based biomarkers can be combined with clinical information to accurately classify AD. A disproportionate number of inflammatory and vascular markers were weighted most heavily in the analyses. Additionally, these markers consistently distinguished cases from controls in significant analysis of microarray, logistic regression, and Wilcoxon analyses, suggesting the existence of an inflammatory-related endophenotype of AD that may provide targeted therapeutic opportunities for this subset of patients.

Characteristic Male Urine Microbiomes Associate with Asymptomatic Sexually Transmitted Infection

Abstract: Article discussing research on characteristic male urine microbiomes associated with asymptomatic sexually transmitted infection.

Evaluating the Effectiveness of Video Instruction on Social and Communication Skills Training for Children with Autism Spectrum Disorders: A Review of the Literature.

Abstract: Video instruction as an intervention for teaching skills to children with Autism Spectrum Disorders (ASD) is gaining increased momentum in applied settings. Video instruction, comprised of video modeling, video self-modeling, and point-ofview video, has been utilized in various fields of study with various populations and target behaviors. Literature on video instruction will be reviewed to determine its effects on the acquisition and generalization of social and communication skills for students with ASD in order to determine whether empirical findings support video instruction as an evidence-based practice. Guidelines for effective implementation of video instruction strategies for students with ASD and recommendations for further research will be provided.

Ghana's National Health Insurance Scheme in the context of the health MDGs: an empirical evaluation using propensity score matching.

Abstract: In 2003 the Government of Ghana established a National Health Insurance Scheme (NHIS) to improve health care access for Ghanaians and eventually replace the cashand-carry system. This study evaluates the NHIS to determine whether it is fulfi lling its purpose in the context of the Millennium Development Goals #4 and #5 which deal with the health of women and children. We use Propensity Score Matching techniques to balance the relevant background characteristics in our survey data and compare health outcomes of recent mothers who are enrolled in the NHIS with those who are not. Our fi ndings suggest that NHIS women are more likely to receive prenatal care, deliver at a hospital, have their deliveries attended by trained health professionals, and experience less birth complications. We conclude that NHIS is an eff ective tool for increasing health care access, and improving health outcomes. JEL Classifi cation: I18, O12, C21

Validation of the New Interpretive Guidelines for the Clinical Dementia Rating Scale Sum of Boxes Score in the National Alzheimer's Coordinating Center Database

Abstract: Background It was recently demonstrated that the Clinical Dementia Rating scale Sum of Boxes (CDR-SB) score can be used to accurately stage severity of Alzheimer dementia and mild cognitive impairment (MCI). However, to our knowledge, the utility of those interpretive guidelines has not been cross-validated or applied to a heterogeneous sample of dementia cases. Objective To cross-validate the staging guidelines proposed in a previous study using the National Alzheimer's Coordinating Center (NACC) database. Design The previously published cut scores were applied to the NACC sample and diagnostic accuracy estimates obtained. Next, analyses were restricted to NACC participants with a CDR global score (CDR-GS) of 0.5 and receiver operating characteristic curves generated to determine optimal CDR-SB cut scores for distinguishing MCI from very early dementia. Setting The 2008 NACC uniform data set. Participants There were 12 462 participants (5115 controls; 2551 patients with MCI; 4796 patients with dementia, all etiologies) in the NACC data set used for the current analysis. Main Outcome Measure Accurate prediction of diagnoses (MCI or dementia) using the CDR-SB score. Results The previously proposed CDR-SB ranges successfully classified the vast majority of patients across all impairment ranges with a κ of 0.91 and 94% overall correct classification rate. Additionally, the CDR-SB score discriminated between patients diagnosed with MCI and dementia when CDR-GS was restricted to 0.5 (overall area under the curve = 0.83). Conclusions These findings cross-validate the previously published CDR-SB interpretative guidelines for staging dementia severity and extend those findings to a large heterogeneous sample of patients with dementia. Additionally, the CDR-SB scores distinguished MCI from dementia in patients with reasonable accuracy when CDR-GS was restricted to 0.5.

Free zinc ions outside a narrow concentration range are toxic to a variety of cells in vitro

Abstract: The zinc(II) ion has recently been implicated in a number of novel functions and pathologies in loci as diverse as the brain, retina, small intestine, prostate, heart, pancreas, and immune system. ...

Patch dynamics and environmental heterogeneity in lotic ecosystems

Abstract: We reviewed concepts of patch dynamics and environmental heterogeneity and their applications to the study of fluvial ecosystems, with emphasis on research published in J-NABS. We discuss several important papers synthesizing theories and findings on this topic and reports of descriptive and experimental research. A large body of research, much of it published in J-NABS, has demonstrated how spatial and temporal variation influences population, community, and ecosystem patterns and processes in fluvial ecosystems. Conceptual models of patch dynamics can be traced to 2 basic approaches: 1) the landscape ecology perspective and 2) the metacommunity perspective. The former focuses on how spatial patterns are created and affect ecological processes over variable scales of space and time, whereas the latter emphasizes the important influence of periodic disturbances, refugia, and dispersal in maintaining nonequilibrium communities within patch mosaics. The origin of the metacommunity Patch Dynamics Con...

High capacity and excellent stability of lithium ion battery anode using interface-controlled binder-free multiwall carbon nanotubes grown on copper.

Abstract: We present a novel binder-free multiwall carbon nanotube (MWCNT) structure as an anode in Li ion batteries. The interface-controlled MWCNT structure, synthesized through a two-step process of catalyst deposition and chemical vapor deposition (CVD) and directly grown on a copper current collector, showed very high specific capacity, almost three times as that of graphite, excellent rate capability even at a charging/discharging rate of 3 C, and no capacity degradation up to 50 cycles. Significantly enhanced properties of this anode could be related to high Li ion intercalation on the carbon nanotube walls, strong bonding with the substrate, and excellent conductivity.