Showing papers by "Wichita State University published in 2013"

Integrating service quality with system and information quality: an empirical test in the e-service context

Abstract: Wixom and Todd (2005) integrated the user satisfaction and the technology acceptance literatures to theorize about and account for the influence of the information technology artifact on usage. Based on Wixom and Todd's integrated model of technology usage, we propose the 3Q model by investigating the role of service quality (SQ), in addition to system quality (SysQ) and information quality (IQ), in website adoption. Attention to SQ is critical, as consumer websites have increasingly become the target of SQ assessment made by consumers, not just traditional SysQ and IQ evaluations. As part of our study, we further theorize and empirically test the relationships among these three types of quality constructs and hypothesize that perceived SysQ influences perceived IQ and perceived SQ, and perceived IQ influences perceived SQ. Our study extends the Wixom and Todd model in the e-service context and is the first of its kind to empirically examine the combined impact of perceived SQ, perceived SysQ, and perceived IQ on usage intention. Our study advances the theoretical understanding of SQ and the relationships among perceptions of SysQ, IQ, and SQ in the e-service context. The results also inform practitioners that high IQ and SysQ can directly or indirectly improve SQ in the e-service context.

Superhydrophobic electrospun nanofibers

Abstract: This review describes state-of-the-art scientific and technological developments of electrospun nanofibers and their use in self-cleaning membranes, responsive smart materials, and other related applications. Superhydrophobic self-cleaning, also called the lotus effect, utilizes the right combinations of surface chemistry and topology to form a very high contact angle on a surface and drive water droplets away from it. The high-contact-angle water droplets easily roll off the surface, carrying with them dirt, particles, and other contaminants by way of gravity. A brief introduction to the theory of superhydrophobic self-cleaning and the basic principles of the electrospinning process is presented. Also discussed is electrospinning for the purpose of creating superhydrophobic self-cleaning surfaces under a wide variety of parameters that allow effective control of roughness of the porous structure with hydrophobic entities. The main principle of electrospinning at the nanoscale and existing difficulties in synthesis of one-dimensional materials by electrospinning are also covered thoroughly. The results of different electrospun nanofibers are compared to each other in terms of their superhydrophobic properties and their scientific and technological applications.

Study of the effect of contact force model on the dynamic response of mechanical systems with dry clearance joints: computational and experimental approaches

Abstract: The main objective of this work is to present a computational and experimental study on the contact forces developed in revolute clearance joints. For this purpose, a well-known slider-crank mechanism with a revolute clearance joint between the connecting rod and slider is utilized. The intra-joint contact forces that are generated at these clearance joints are computed by considering several different elastic and dissipative approaches, namely those based on the Hertz contact theory and the ESDU tribology-based cylindrical contacts, along with a hysteresis-type dissipative damping. The normal contact force is augmented with the dry Coulomb’s friction force. In addition, an experimental apparatus is used to obtained some experimental data in order to verify and validate the computational models. From the outcomes reported in this paper, it is concluded that the selection of the appropriate contact force model with proper dissipative damping plays a significant role in the dynamic response of mechanical systems involving contact events at low or moderate impact velocities.

A near-optimal algorithm for differentially-private principal components

Abstract: The principal components analysis (PCA) algorithm is a standard tool for identifying good low-dimensional approximations to high-dimensional data. Many data sets of interest contain private or sensitive information about individuals. Algorithms which operate on such data should be sensitive to the privacy risks in publishing their outputs. Differential privacy is a framework for developing tradeoffs between privacy and the utility of these outputs. In this paper we investigate the theory and empirical performance of differentially private approximations to PCA and propose a new method which explicitly optimizes the utility of the output. We show that the sample complexity of the proposed method differs from the existing procedure in the scaling with the data dimension, and that our method is nearly optimal in terms of this scaling. We furthermore illustrate our results, showing that on real data there is a large performance gap between the existing method and our method.

A Maximum Confidence Enhancement Based Sequential Sampling Scheme for Simulation-Based Design

Abstract: This paper presents a maximum confidence enhancement based sequential sampling approach for simulation-based design under uncertainty. In the proposed approach, the ordinary Kriging method is adopted to construct surrogate models for all constraints and thus Monte Carlo simulation (MCS) is able to be used to estimate reliability and its sensitivity with respect to design variables. A cumulative confidence level is defined to quantify the accuracy of reliability estimation using MCS based on the Kriging models. To improve the efficiency of proposed approach, a maximum confidence enhancement based sequential sampling scheme is developed to update the Kriging models based on the maximum improvement of the defined cumulative confidence level, in which a sample that produces the largest improvement of the cumulative confidence level is selected to update the surrogate models. Moreover, a new design sensitivity estimation approach based upon constructed Kriging models is developed to estimate the reliability sensitivity information with respect to design variables without incurring any extra function evaluations. This enables to compute smooth sensitivity values and thus greatly enhances the efficiency and robustness of the design optimization process. Two case studies are used to demonstrate the proposed methodology.Copyright © 2013 by ASME

The effects of carbon dioxide and temperature on microRNA expression in Arabidopsis development

Abstract: An increase in the concentration of atmospheric carbon dioxide and warmer temperatures can alter plant growth and development. Here the authors show that these conditions can also elicit significant changes in microRNAs expression, including some which might induce early flowering in Arabidopsis.

Energy and spectrum-aware MAC protocol for perpetual wireless nanosensor networks in the Terahertz Band

Abstract: Wireless NanoSensor Networks (WNSNs), i.e., networks of nanoscale devices with unprecedented sensing capabilities, are the enabling technology of long-awaited applications such as advanced health monitoring systems or surveillance networks for chemical and biological attack prevention. The peculiarities of the Terahertz Band, which is the envisioned frequency band for communication among nano-devices, and the extreme energy limitations of nanosensors, which require the use of nanoscale energy harvesting systems, introduce major challenges in the design of MAC protocols for WNSNs. This paper aims to design energy and spectrum-aware MAC protocols for WNSNs with the objective to achieve fair, throughput and lifetime optimal channel access by jointly optimizing the energy harvesting and consumption processes in nanosensors. Towards this end, the critical packet transmission ratio (CTR) is derived, which is the maximum allowable ratio between the transmission time and the energy harvesting time, below which a nanosensor can harvest more energy than the consumed one, thus achieving perpetual data transmission. Based on the CTR, first, a novel symbol-compression scheduling algorithm, built on a recently proposed pulse-based physical layer technique, is introduced. The symbol-compression solution utilizes the unique elasticity of the inter-symbol spacing of the pulse-based physical layer to allow a large number of nanosensors to transmit their packets in parallel without inducing collisions. In addition, a packet-level timeline scheduling algorithm, built on a theoretical bandwidth-adaptive capacity-optimal physical layer, is proposed with an objective to achieve balanced single-user throughput with infinite network lifetime. The simulation results show that the proposed simple scheduling algorithms can enable nanosensors to transmit with extremely high speed perpetually without replacing the batteries.

Family relationships and adolescent well-being: are families equally protective for same-sex attracted youth?

Abstract: Existing research suggests that sexual minority youth experience lower levels of well-being, in part because they perceive less social support than heterosexual youth. Sexual minority youth with strong family relationships may demonstrate resilience and increased well-being; however, it is also possible that the experience of sexual stigma may make these relationships less protective for sexual minority youth. Using two waves of data from the National Longitudinal Study of Adolescent Health, we explore the links between same-sex attraction, family relationships, and adolescent well-being in a sample of over 13,000 7th–12th grade adolescents (51 % female, 52 % non-Latino/a white, 17 % Latino, 21 % African American, and 7 % Asian). Specifically, we examine whether lower levels of parental closeness, parental involvement, and family support among same-sex attracted youth explain in part why these youth experience increased depressive symptoms and risk behaviors, including binge drinking, illegal drug use, and running away from home, relative to other-sex attracted youth. Second, we ask whether family relationships are equally protective against depressive symptoms and risk behaviors for same-sex attracted and other-sex attracted youth. We find that same-sex attracted youth, particularly girls, report higher levels of depressive symptoms, binge drinking, and drug use in part because they perceive less closeness with parents and less support from their families. Results also suggest that parental closeness and parental involvement may be less protective against risk behaviors for same-sex attracted boys than for their other-sex attracted peers. Findings thus suggest that interventions targeting the families of sexual minority youth should educate parents about the potentially negative effects of heteronormative assumptions and attitudes on positive adolescent development.

Guilt, Shame, and Reparative Behavior: The Effect of Psychological Proximity

Abstract: Research has paid scant attention to reparative behavior to compensate for unintended wrongdoing or to the role of emotions in doing the right thing. We propose a new approach to investigating reparative behavior by looking at moral emotions and psychological proximity. In this study, we compare the effects of moral emotions (guilt and shame) on the level of compensation for financial harm. We also investigate the role of transgressors’ perceived psychological proximity to the victims of wrongdoing. Our hypotheses were tested through a scenario based questionnaire on a sample of 261 participants. Analyses indicate that (1) guilt has a stronger effect on the level of compensation than shame; (2) psychological proximity influences the level of guilt, shame, and compensation; and (3) shame interacts with psychological proximity to predict compensation, whereas guilt mediates the relationship between psychological proximity and compensation.

The Role of Social-Emotional Learning In Bullying Prevention Efforts

Abstract: This article examines how social emotional learning contributes to bullying prevention efforts in schools. Bullying behavior is impacted by multiple levels of the social-ecology of schools. Social emotional learning (SEL) is a structured way to improve a wide range of students' social and emotional competencies and impact bullying at the individual and peer levels of the school social-ecology. SEL has been shown to be an effective component in comprehensive bullying prevention interventions and other interventions targeting problems such as substance abuse. SEL programs have also been shown to improve student skills, reduce problem behaviors, and increase academic achievement. This article discusses how skills taught in SEL programs contribute to bullying prevention and shows the research links between SEL skills and bullying. Specific suggestions are provided for teachers of ways to support student skill acquisition and strengthen the gains provided by SEL programs.

Recent progress on conventional and non-conventional electrospinning processes

Abstract: Electrospinning is a process of producing micro- and nanoscale fibers using electrostatically charged polymeric solutions under various conditions. Most synthetic and naturally occurring polymers can be electrospun using appropriate solvents and/or their blends. Because of the fascinating properties of electrospun fibers, electrospinning has recently attracted enormous attention worldwide. Initially, this method did not receive much industrial attention due to lower production rates, costs, and lack of interest in size, shape, and flexibility of electrospun nanofibers. However, with the advancement of needleless electrospinning, multiple needles in series, near-field electrospinning techniques, and nanotechnology in particular, this is no longer an issue. This paper outlines the recent progress on the production of various sizes and shapes of fibers using conventional and non-conventional electrospinning processes (e.g., rotating drum and disc, translating spinnerets, rotating strings of electrodes in polymeric solutions, and forcespinning) and presents a complete view of electrospun fiber productions techniques and the resultant products’ applications in different fields to date.

Vertical Farming: Social Work and Sustainable Urban Agriculture in an Age of Global Food Crises

Abstract: Environmental concerns, including issues of ecological justice, attention to sustainability, and focus on issues of food security have gathered increased momentum in social work. This article will trace the background of sustainable urban agriculture as a partial solution to the issue of global food insecurity and its impact on marginalised urban populations. It will review the development of a sustainable agricultural initiative called vertical farming and suggest that it holds promise for communities struggling with chronic food security problems. It will outline some tentative steps social work may consider in order to become more fully involved in support of vertical farming initiatives.

Integrating conceptual and logical couplings for change impact analysis in software

Abstract: The paper presents an approach that combines conceptual and evolutionary techniques to support change impact analysis in source code. Conceptual couplings capture the extent to which domain concepts and software artifacts are related to each other. This information is derived using Information Retrieval based analysis of textual software artifacts that are found in a single version of software (e.g., comments and identifiers in a single snapshot of source code). Evolutionary couplings capture the extent to which software artifacts were co-changed. This information is derived from analyzing patterns, relationships, and relevant information of source code changes mined from multiple versions in software repositories. The premise is that such combined methods provide improvements to the accuracy of impact sets compared to the two individual approaches. A rigorous empirical assessment on the changes of the open source systems Apache httpd, ArgoUML, iBatis, KOffice, and jEdit is also reported. The impact sets are evaluated at the file and method levels of granularity for all the software systems considered in the empirical evaluation. The results show that a combination of conceptual and evolutionary techniques, across several cut-off points and periods of history, provides statistically significant improvements in accuracy over either of the two techniques used independently. Improvements in F-measure values of up to 14% (from 3% to 17%) over the conceptual technique in ArgoUML at the method granularity, and up to 21% over the evolutionary technique in iBatis (from 9% to 30%) at the file granularity were reported.

Understanding post‐adoption IS usage stages: an empirical assessment of self‐service information systems

Abstract: Organisations have invested in self-service information systems (IS) to provide a direct interface for service delivery. Enriching the usage of these systems can provide organisations with immense benefits. However, limited research has been directed towards understanding post-adoption IS usage behaviour in general and specifically in the context of self-service IS. This study proposes post-adoption IS usage behaviour as a broader concept constituting feature level usage of IS, integration of IS in the work system and exploration of new uses of IS. We evaluate how the new conceptualisation can be used to classify users at different stages of self-service IS usage. Further, we examine user perceptions that differentiate among the users situated at different self-service IS usage stages. Data were collected in the context of a self-service Web-based IS to validate the post-adoption IS usage constructs and to examine the proposed thesis. The newly developed conceptual structure and measures for post-adoption IS usage behaviour exhibit strong psychometric properties. The analysis shows three distinct post-adoption IS usage stages and highlights that usefulness, user-initiated learning, ease of use, satisfaction and voluntariness of use differentiate users at the different stages of post-adoption IS usage. The results show that these variables aggregate into value confirmation and learning orientation as two higher-level concepts. Further, we evaluate the predictive efficacy of the research model in classifying users into different post-adoption self-service IS usage stages. Implications are drawn for future research.

Functional Performance Testing for Power and Return to Sports

Abstract: Context:Functional performance testing of athletes can determine physical limitations that may affect sporting activities. Optimal functional performance testing simulates the athlete’s activity.Evidence Acquisition:A Medline search from 1960 to 2012 was implemented with the keywords functional testing, functional impairment testing, and functional performance testing in the English language. Each author also undertook independent searches of article references.Conclusion:Functional performance tests can bridge the gap between general physical tests and full, unrestricted athletic activity.

Simulations of protostellar collapse using multigroup radiation hydrodynamics

Abstract: Context. Star formation begins with the gravitational collapse of a dense core inside a molecular cloud. As the collapse progresses, the centre of the core begins to heat up as it becomes optically thick. The temperature and density in the centre eventually reach high enough values where fusion reactions can ignite, and the protostar is born. This sequence of events entails many physical processes, of which radiative transfer is of paramount importance. Simulated collapsing cores without radiative transfer rapidly become thermally supported before reaching high enough temperatures and densities, preventing the formation of stars.Aims. Many simulations of protostellar collapse make use of a grey treatment of radiative transfer coupled to the hydrodynamics. However, interstellar gas and dust opacities present large variations as a function of frequency, which can potentially be overlooked by grey models and lead to significantly different results. In this paper, we follow up on a previous paper on the collapse and formation of Larson’s first core using multigroup radiation hydrodynamics (Paper I) by extending the calculations to the second phase of the collapse and the formation of Larson’s second core.Methods. We have made the use of a non-ideal gas equation of state as well as an extensive set of spectral opacities in a spherically symmetric fully implicit Godunov code to model all the phases of the collapse of a 0.1, 1, and 10 M⊙ cloud cores.Results. We find that, for an identical central density, there are only small differences between the grey and multigroup simulations. The first core accretion shock remains supercritical while the shock at the second core border is found to be strongly subcritical with all the accreted energy being transfered to the core. The size of the first core was found to vary somewhat in the different simulations (more unstable clouds form smaller first cores) while the size, mass, and temperature of the second cores are independent of initial cloud mass, size, and temperature.Conclusions. Our simulations support the idea of a standard (universal) initial second core size of ~3 × 10-3 AU and mass ~1.4 × 10-3 M⊙. The grey approximation for radiative transfer appears to perform well in one-dimensional simulations of protostellar collapse, most probably because of the high optical thickness of the majority of the protostar-envelope system. A simple estimate of the characteristic timescale of the second core suggests that the effects of using multigroup radiative transfer may be more important in the long-term evolution of the protostar.

The effects of elastic band resistance training combined with blood flow restriction on strength, total bone‐free lean body mass and muscle thickness in postmenopausal women

Abstract: Summary Introduction Elastic band (EB) training is a common form of resistance training used by the elderly, individuals with joint problems or those recovering from injury. EB training performed at low intensities by these populations may have little effect on muscle hypertrophy. However, when combined with blood flow restriction (BFR), low-intensity EB resistance training may result in muscle hypertrophy. Methods Postmenopausal women (61 ± 5 years) were assigned to a moderate-to-high-intensity EB group (MH, n = 8) or a low-intensity EB group combined with BFR (LI-BFR, n = 6). Each group performed seated chest press, seated row and seated shoulder press with EB three times a week for eight weeks. EB colours progressed in each group by having participants maintain a rating of 7–9 on the OMNI Resistance for active muscle (OMNI-RES AM) scale (0–10) throughout training. In the LI-BFR group, BFR pressure progressed during the first 4 weeks of training (80–120 mmHg), after which EB colours were progressed. Results 1-repetition maximum increased for chest press (P = 0·01), shoulder press (P = 0·02) and seated row (P = 0·01), but no differences were found between groups. Only pectoralis major muscle thickness in the upper body increased (P = 0·04). A trend was found for an increase in total bone-free lean body mass (P = 0·055). Conclusions The main findings of this study were that moderate-to-high-intensity EB training and low-intensity EB training with BFR resulted in similar increases in strength, total bone-free lean body mass and muscle thickness.

What Performance Characteristics Determine Elite Versus Nonelite Athletes in the Same Sport

Abstract: Context:There are significant data comparing elite and nonelite athletes in anaerobic field and court sports as well as endurance sports This review delineates specific performance characteristics in the elite athlete and may help guide rehabilitationEvidence Acquisition:A Medline search from April 1982 to April 2012 was undertaken for articles written in English Additional references were accrued from reference lists of research articlesResults:In the anaerobic athlete, maximal power production was consistently correlated to elite performance Elite performance in the endurance athlete is more ambiguous, however, and appears to be related to the dependent variable investigated in each individual studyConclusion:In anaerobic field and court sport athletes, maximal power output is most predictive of elite performance In the endurance athlete, however, it is not as clear Elite endurance athletes consistently test higher than nonelite athletes in running economy, anaerobic threshold, and VO2max

Increasing consumption of fruits and vegetables in the school cafeteria: the influence of active choice

Abstract: This study evaluated a setting-level intervention designed to increase consumption of fruits and vegetables among low-socioeconomic status elementary and middle school students participating in the National School Lunch Program (NSLP). The NSLP provides students with access to fruits and vegetables; however, food served does not necessarily equal food consumed. High rates of waste, especially of fruits and vegetables, are well documented. The current, low-cost intervention altered the choice architecture of the cafeteria by introducing an active, forced choice into the school lunch service. Consumption was measured by observing (n=2,064) and weighing (n=84) student plate waste over two 10-day periods pre-intervention and during implementation. Results show an average daily 15% increase in consumption of both fruits and vegetables during the intervention period. These findings suggest that local schools can actively encourage students to take advantage of fruits and vegetables offered through the NSLP by implementing setting-level changes to the cafeteria environment.

Excitation‐Wavelength‐Dependent, Ultrafast Photoinduced Electron Transfer in Bisferrocene/BF2‐Chelated‐Azadipyrromethene/Fullerene Tetrads

Abstract: Donor-acceptor distance, orientation, and photoexcitation wavelength are key factors in governing the efficiency and mechanism of electron-transfer reactions both in natural and synthetic systems. Although distance and orientation effects have been successfully demonstrated in simple donor-acceptor dyads, revealing excitation-wavelength-dependent photochemical properties demands multimodular, photosynthetic-reaction-center model compounds. Here, we successfully demonstrate donor- acceptor excitation-wavelength-dependent, ultrafast charge separation and charge recombination in newly synthesized, novel tetrads featuring bisferrocene, BF2 -chelated azadipyrromethene, and fullerene entities. The tetrads synthesized using multistep synthetic procedure revealed characteristic optical, redox, and photo reactivities of the individual components and featured "closely" and "distantly" positioned donor-acceptor systems. The near-IR-emitting BF2-chelated azadipyrromethene acted as a photosensitizing electron acceptor along with fullerene, while the ferrocene entities acted as electron donors. Both tetrads revealed excitation-wavelength-dependent, photoinduced, electron-transfer events as probed by femtosecond transient absorption spectroscopy. That is, formation of the Fc(+)-ADP-C60(.-) charge-separated state upon C60 excitation, and Fc(+)-ADP(.-)-C60 formation upon ADP excitation is demonstrated.

Collagen microsphere serving as a cell carrier supports oligodendrocyte progenitor cell growth and differentiation for neurite myelination in vitro

Abstract: Microspheres fabricated from natural materials serve as a promising biodegradable and biocompatible carrier in a small volume for efficient cell delivery to the lesion of the injured neural tissue to generate biological functions. As the major component of extracellular matrix and due to its natural abundance within the body, collagen may be fabricated into microspheres and improve the ability of pre-seeded cells on the microspheres to encounter the hostile micro-environment in the lesion. In this study, collagen microspheres were fabricated using the water-in-oil emulsion technique and cross-linked with 1-ethyl-3-(3-dimethylaminopropryl) carbodiimide. Oligodendrocyte progenitor cells isolated from postnatal day P1 to 2 rats were cultured and differentiated on the microspheres. The microspheres carrying the oligodendrocyte progenitor cells were co-cultured with dorsal root ganglions from 15-day-old rat embryos. The myelination formation was studied for the co-culture of oligodendrocyte progenitor cells and dorsal root ganglions. We showed that the viability of oligodendrocyte progenitor cells, B104 cells and PC12 cells grown on microspheres was not significantly different with those in cell culture plates. Oligodendrocyte progenitor cells differentiated into oligodendrocytes on collagen microspheres. The oligodendrocytes grown on microspheres extended processes that wrapped the axons of dorsal root ganglion neurons and the formation of myelin sheath was observed in the co-culture. This study demonstrates the feasibility of collagen microspheres in further applications for the delivery of neural progenitor cells for neural regeneration.

Photometric properties of stellar populations in Galactic globular clusters: the role of the Mg-Al anticorrelation

Abstract: We have computed low-mass stellar models and synthetic spectra for an initial chemical composition that includes the full C-N, O-Na, and Mg-Al abundance anticorrelations observed in second-generation stars belonging to a number of massive Galactic globular clusters. This investigation extends a previous study that addressed the effect of only the C-N and O-Na anticorrelations seen in all globulars observed to date. We find that the impact of Mg-Al abundance variations at fixed [Fe/H] and helium abundance is negligible on stellar models and isochrones (from the main sequence to the tip of the red giant branch) and bolometric corrections, when compared to the effect of C-N and O-Na variations. We identify a spectral feature at 490–520 nm, for low-mass main sequence stars, caused by MgH molecular bands. This feature has a vanishingly small effect on bolometric corrections for Johnson and Stromgren filters that cover that spectral range. However, specific narrow-band filters able to target this wavelength region can be powerful tools for investigating the Mg-poor unevolved stars and highlight possible splittings of the main sequence due to variations of Mg abundances.

Galvanic corrosion of Al/Cu meshes with carbon fibers and graphene and ITO-based nanocomposite coatings as alternative approaches for lightning strikes

Abstract: Earlier airplane fuselages were made primarily of aluminum alloy sheets, which have very good electrical conductivity. If lightning strikes an aluminum alloy surface, the current generated by the lightning can easily flow without interruption or diversion to the interior of the aircraft. Today, fiber-reinforced polymer composites have been widely utilized in aircraft. In order to protect fiber-reinforced composites against lightning strikes, copper (Cu) and aluminum (Al) meshes or metal sheets are used in the uppermost layer. As it is known, carbon fibers are nobler than both Cu and Al meshes, resulting in galvanic corrosion when these dissimilar materials interact with each other under certain environmental conditions. Consequently, corroded metal mesh areas will lose conductivity on the composite surface. For this reason, lightning strike protection is vitally important for the new generation of composite aircraft. In the present study, we systematically studied the galvanic corrosion effects of carbon fibers and metal (Al and Cu) meshes in acidic and salty conditions. We found that environmental conditions had a big impact on the galvanic corrosion between carbon fibers and metal meshes used for fiber-reinforced composites. This paper discusses current lightning strike protection techniques and provides some experimental evidence of graphene and indium-doped tin oxide (ITO)-based nanocomposite coatings on carbon fiber-reinforced composites. This approach may overcome the problem of lightning strikes on composite aircraft and may be useful for redesigning the new generation of composite aircraft.