Showing papers by "Clemson University published in 2014"

Bullying in the Digital Age: A Critical Review and Meta-Analysis of Cyberbullying Research Among Youth

Abstract: Although the Internet has transformed the way our world operates, it has also served as a venue for cyberbullying, a serious form of misbehavior among youth. With many of today's youth experiencing acts of cyberbullying, a growing body of literature has begun to document the prevalence, predictors, and outcomes of this behavior, but the literature is highly fragmented and lacks theoretical focus. Therefore, our purpose in the present article is to provide a critical review of the existing cyberbullying research. The general aggression model is proposed as a useful theoretical framework from which to understand this phenomenon. Additionally, results from a meta-analytic review are presented to highlight the size of the relationships between cyberbullying and traditional bullying, as well as relationships between cyberbullying and other meaningful behavioral and psychological variables. Mixed effects meta-analysis results indicate that among the strongest associations with cyberbullying perpetration were normative beliefs about aggression and moral disengagement, and the strongest associations with cyberbullying victimization were stress and suicidal ideation. Several methodological and sample characteristics served as moderators of these relationships. Limitations of the meta-analysis include issues dealing with causality or directionality of these associations as well as generalizability for those meta-analytic estimates that are based on smaller sets of studies (k < 5). Finally, the present results uncover important areas for future research. We provide a relevant agenda, including the need for understanding the incremental impact of cyberbullying (over and above traditional bullying) on key behavioral and psychological outcomes.

The Dalton quantum chemistry program system

Abstract: Dalton is a powerful general-purpose program system for the study of molecular electronic structure at the Hartree-Fock, Kohn-Sham, multiconfigurational self-consistent-field, MOller-Plesset, confi ...

On the Role of Nonlinearities in Vibratory Energy Harvesting: A Critical Review and Discussion

Abstract: The last two decades have witnessed several advances in microfabrication technologies and electronics, leading to the development of small, low-power devices for wireless sensing, data transmission, actuation, and medical implants. Unfortunately, the actual implementation of such devices in their respective environment has been hindered by the lack of scalable energy sources that are necessary to power and maintain them. Batteries, which remain the most commonly used power sources, have not kept pace with the demands of these devices, especially in terms of energy density. In light of this challenge, the concept of vibratory energy harvesting has flourished in recent years as a possible alternative to provide a continuous power supply. While linear vibratory energy harvesters have received the majority of the literature’s attention, a significant body of the current research activity is focused on the concept of purposeful inclusion of nonlinearities for broadband transduction. When compared to their linear resonant counterparts, nonlinear energy harvesters have a wider steady-state frequency bandwidth, leading to a common belief that they can be utilized to improve performance in ambient environments. Through a review of the open literature, this paper highlights the role of nonlinearities in the transduction of energy harvesters under different types of excitations and investigates the conditions, in terms of excitation nature and potential shape, under which such nonlinearities can be beneficial for energy harvesting. [DOI: 10.1115/1.4026278]

Trust, satisfaction, and online repurchase intention: the moderating role of perceived effectiveness of E-commerce institutional mechanisms

Abstract: The effects of e-commerce institutional mechanisms on trust and online purchase have traditionally been understood in the initial online purchase context. This study extends this literature by exploring the role of e-commerce institutional mechanisms in the online repurchase context. In doing so, it responds to the emerging call for understanding the institutional context under which customer trust operates in an e-commerce environment. Specifically, this study introduces a key moderator, perceived effectiveness of e-commerce institutional mechanisms (PEEIM), to the relationships between trust, satisfaction, and repurchase intention. Drawing on the theory of organizational trust, and based on a survey of 362 returning online customers, we find that PEEIM negatively moderates the relationship between trust in an online vendor and online customer repurchase intention, as it decreases the importance of trust to promoting repurchase behavior. We also find that PEEIM positively moderates the relationship between customer satisfaction and trust as it enhances the customer's reliance on past transaction experience with the vendor to reevaluate trust in the vendor. Consistent with the predictions made in the literature, PEEIM does not directly affect trust or repurchase intention. Academic and practical implications and future research directions are discussed.

The Economics of Bitcoin and Similar Private Digital Currencies

Abstract: Recent innovations have made it feasible to transfer private digital currency without the intervention of an institution. A digital currency must prevent users from spending their balances more than once, which is easier said than done with purely digital currencies. Current digital currencies such as Bitcoin use peer-to-peer networks and open-source software to stop double spending and create finality of transactions. This paper explains how the use of these technologies and limitation of the quantity produced can create an equilibrium in which a digital currency has a positive value. This paper also summarizes the rise of 24/7 trading on computerized markets in Bitcoin in which there are no brokers or other agents, a remarkable innovation in financial markets. I conclude that exchanges of foreign currency may be the obvious way in which use of digital currencies can become widespread and that Bitcoin is likely to limit governments’ revenue from inflation.

Evidence for General and Domain‐Specific Elements of Teacher–Child Interactions: Associations With Preschool Children's Development

Abstract: This study evaluates a model for considering domain-general and domain-specific associations between teacher-child interactions and children's development, using a bifactor analytic strategy. Among a sample of 325 early childhood classrooms there was evidence for both general elements of teacher-child interaction (responsive teaching) and domain-specific elements related to positive management and routines and cognitive facilitation. Among a diverse population of 4-year-old children (n = 1,407) responsive teaching was modestly associated with development across social and cognitive domains, whereas positive management and routines was modestly associated with increases in inhibitory control and cognitive facilitation was associated with gains in early language and literacy skills. The conceptual and methodological contributions and challenges of this approach are discussed.

Finding the missing honey bee genes: Lessons learned from a genome upgrade

Abstract: The first generation of genome sequence assemblies and annotations have had a significant impact upon our understanding of the biology of the sequenced species, the phylogenetic relationships among species, the study of populations within and across species, and have informed the biology of humans. As only a few Metazoan genomes are approaching finished quality (human, mouse, fly and worm), there is room for improvement of most genome assemblies. The honey bee (Apis mellifera) genome, published in 2006, was noted for its bimodal GC content distribution that affected the quality of the assembly in some regions and for fewer genes in the initial gene set (OGSv1.0) compared to what would be expected based on other sequenced insect genomes. Here, we report an improved honey bee genome assembly (Amel_4.5) with a new gene annotation set (OGSv3.2), and show that the honey bee genome contains a number of genes similar to that of other insect genomes, contrary to what was suggested in OGSv1.0. The new genome assembly is more contiguous and complete and the new gene set includes ~5000 more protein-coding genes, 50% more than previously reported. About 1/6 of the additional genes were due to improvements to the assembly, and the remaining were inferred based on new RNAseq and protein data. Lessons learned from this genome upgrade have important implications for future genome sequencing projects. Furthermore, the improvements significantly enhance genomic resources for the honey bee, a key model for social behavior and essential to global ecology through pollination.

Corporate Social Responsibility, Customer Orientation, and the Job Performance of Frontline Employees.

Abstract: This study examines frontline employee responses to corporate social responsibility (CSR) using a multisourced data set at a Global 500 financial services company. The authors find that frontline employees identify with the organization (i.e., organizational identification) and with customers (i.e., employee–customer identification) as a function of how much the employees perceive management and customers (respectively) to support the company's CSR activities. However, these respective effects are stronger among employees for whom CSR is already tied to their sense of self (i.e., CSR importance to the employee). In addition, both organizational identification and employee–customer identification are related to supervisor-rated job performance; however, only the effect of employee–customer identification is mediated by customer orientation, suggesting that these two targets of identification manifest through distinct mechanisms. The research empirically addresses the open questions of whether and when CSR ...

Analysis of the Genome and Transcriptome of Cryptococcus neoformans var. grubii Reveals Complex RNA Expression and Microevolution Leading to Virulence Attenuation

Abstract: Cryptococcus neoformans is a pathogenic basidiomycetous yeast responsible for more than 600,000 deaths each year. It occurs as two serotypes (A and D) representing two varieties (i.e. grubii and neoformans, respectively). Here, we sequenced the genome and performed an RNA-Seq-based analysis of the C. neoformans var. grubii transcriptome structure. We determined the chromosomal locations, analyzed the sequence/structural features of the centromeres, and identified origins of replication. The genome was annotated based on automated and manual curation. More than 40,000 introns populating more than 99% of the expressed genes were identified. Although most of these introns are located in the coding DNA sequences (CDS), over 2,000 introns in the untranslated regions (UTRs) were also identified. Poly(A)-containing reads were employed to locate the polyadenylation sites of more than 80% of the genes. Examination of the sequences around these sites revealed a new poly(A)-site-associated motif (AUGHAH). In addition, 1,197 miscRNAs were identified. These miscRNAs can be spliced and/or polyadenylated, but do not appear to have obvious coding capacities. Finally, this genome sequence enabled a comparative analysis of strain H99 variants obtained after laboratory passage. The spectrum of mutations identified provides insights into the genetics underlying the micro-evolution of a laboratory strain, and identifies mutations involved in stress responses, mating efficiency, and virulence.

Accelerating charging dynamics in subnanometre pores.

Abstract: Supercapacitors have exceptional power density and cyclability but smaller energy density than batteries. Their energy density can be increased using ionic liquids and electrodes with subnanometre pores, but this tends to reduce their power density and compromise the key advantage of supercapacitors. To help address this issue through material optimization, here we unravel the mechanisms of charging subnanometre pores with ionic liquids using molecular dynamics simulations, navigated by a phenomenological model. We show that charging of ionophilic pores is a diffusive process, often accompanied by overfilling followed by de-filling. In sharp contrast to conventional expectations, charging is fast because ion diffusion during charging can be an order of magnitude faster than in the bulk, and charging itself is accelerated by the onset of collective modes. Further acceleration can be achieved using ionophobic pores by eliminating overfilling/de-filling and thus leading to charging behaviour qualitatively different from that in conventional, ionophilic pores.

Carbon-based quantum dots for fluorescence imaging of cells and tissues

Abstract: Carbon dots (or carbon quantum dots in some literature reports), generally small carbon nanoparticles with various surface passivation effects, have attracted widespread attention in recent years, with a rapidly increasing number of research publications. The reported studies covered many aspects of carbon dots, from the development of many new synthetic methodologies to an improved mechanistic elucidation and to the exploration of application opportunities, especially for those in the fluorescence imaging of cells and tissues. There have also been significant advances in the establishment of a shared mechanistic framework for carbon dots and other carbon-based quantum dots, graphene quantum dots in particular. In this article, representative recent studies for more efficient syntheses of better-performing carbon dots are highlighted along with results from explorations of their various bioimaging applications in vitro and in vivo. Similar fluorescence properties and potential imaging uses of some graphene quantum dots are also discussed, toward a more consistent and uniform understanding of phenomenologically different carbon-based quantum dots.

Environmental education program evaluation in the new millennium: what do we measure and what have we learned?

Abstract: We conducted a systematic literature review of peer-reviewed research studies published between 1999 and 2010 that empirically evaluated the outcomes of environmental education (EE) programs for youth (ages 18 and younger) in an attempt to address the following objectives: (1) to seek reported empirical evidence for what works (or does not) in EE programming and (2) to uncover lessons regarding promising approaches for future EE initiatives and their evaluation. While the review generally supports consensus-based best practices, such as those published in the North American Association for Environmental Education’s Guidelines for Excellence, we also identified additional themes that may drive positive outcomes, including the provision of holistic experiences and the characteristics and delivery styles of environmental educators. Overall, the evidence in support of these themes contained in the 66 articles reviewed is mostly circumstantial. Few studies attempted to empirically isolate the characteristics of programs responsible for measured outcomes. We discuss general trends in research design and the associated implications for future research and EE programming.

It's What You Make of It: Founder Identity and Enacting Strategic Responses to Adversity

Abstract: We conducted a longitudinal field study of 13 resource-constrained founder-run textile and apparel firms to understand how and why firms vary in their strategic responses to the same adversity. We discovered that founders enact distinctly different definitions of the adversity and use their firms as vehicles to defend who they are or to become who they want to be. Bridging two formerly disparate social psychological theories of identity, we develop grounded theory and a process model that together contribute toward our understanding of how and why differences in the structure of founder identity—the set of identities that is chronically salient to a founder in her/his day-to-day work—drive patterned differences in firms’ strategic responses. The processes we describe help explain responses to adversity and also provide a platform for research that may generate new insights into the significance for founders of bringing “who I am” into closer alignment with “who I want to be.”

FLOWGUARD: building robust firewalls for software-defined networks

Abstract: Software-Defined Networking (SDN) introduces significant granularity, visibility and flexibility to networking, but at the same time brings forth new security challenges. One of the fundamental challenges is to build robust firewalls for protecting OpenFlow-based networks where network states and traffic are frequently changed. To address this challenge, we introduce FlowGuard, a comprehensive framework, to facilitate not only accurate detection but also effective resolution of firewall policy violations in dynamic OpenFlow-based networks. FlowGuard checks network flow path spaces to detect firewall policy violations when network states are updated. In addition, FlowGuard conducts automatic and real-time violation resolutions with the help of several innovative resolution strategies designed for diverse network update situations. We also implement our framework and demonstrate the efficacy and efficiency of the proposed detection and resolution approaches in FlowGuard through experiments with a real-world network topology.

Functional properties of vinegar.

Abstract: A variety of natural vinegar products are found in civilizations around the world. A review of research on these fermented products indicates numerous reports of health benefits derived by consumption of vinegar components. Therapeutic effects of vinegar arising from consuming the inherent bioactive components including acetic acid, gallic acid, catechin, ephicatechin, chlorogenic acid, caffeic acid, p-coumaric acid, and ferulic acid cause antioxidative, antidiabetic, antimicrobial, antitumor, antiobesity, antihypertensive, and cholesterol-lowering responses. The aims of this article are to discuss vinegar history, production, varieties, acetic acid bacteria, and functional properties of vinegars.

Damaging effects of a high-fat diet to the brain and cognition: A review of proposed mechanisms

Abstract: The prevalence of obesity is growing and now includes at least one-third of the adult population in the United States. As obesity and dementia rates reach epidemic proportions, an even greater interest in the effects of nutrition on the brain have become evident. This review discusses various mechanisms by which a high fat diet and/or obesity can alter the brain and cognition. It is well known that a poor diet and obesity can lead to certain disorders such as type II diabetes, metabolic syndrome, and heart disease. However, long-term effects of obesity on the brain need to be further examined. The contribution of insulin resistance and oxidative stress is briefly reviewed from studies in the current literature. The role of inflammation and vascular alterations are described in more detail due to our laboratory's experience in evaluating these specific factors. It is very likely that each of these factors plays a role in diet-induced and/or obesity-induced cognitive decline.

Looking toward the future of IT-bUSINESS strategic alignment through the past: a meta-analysis

Abstract: Research examining the relationship between IT-business strategic alignment (hereafter referred to as alignment) and firm performance (hereafter referred to as performance) has produced apparently conflicting findings (i.e., an alignment paradox). To examine the alignment paradox, we conducted a meta-analysis that probed the interrelationships between alignment, performance, and context constructs. We found the alignment dimensions (intellectual, operational, and cross-domain) demonstrate unique relationships with the different performance types (financial performance, productivity, and customer benefit) and with many of the other constructs in alignment's nomological network. All mean corrected correlations between dimensions of alignment and dependent variables were positive and most of the credibility interval values in these analyses were also positive. Overall, the evidence gathered from the extant literature suggests there is not much of an alignment paradox. This study contributes to the literature by clarifying the relationships between alignment and performance outcomes and offering insight into sources of inconsistencies in alignment research. By doing so, this paper lays a foundation for more consistent treatment of alignment in future IT research.

Design and Synthesis of Copper–Cobalt Catalysts for the Selective Conversion of Synthesis Gas to Ethanol and Higher Alcohols

Abstract: Combining quantum-mechanical simulations and synthesis tools allows the design of highly efficient CuCo/MoOx catalysts for the selective conversion of synthesis gas (CO+H2) into ethanol and higher alcohols, which are of eminent interest for the production of platform chemicals from non-petroleum feedstocks. Density functional theory calculations coupled to microkinetic models identify mixed Cu-Co alloy sites, at Co-enriched surfaces, as ideal for the selective production of long-chain alcohols. Accordingly, a versatile synthesis route is developed based on metal nanoparticle exsolution from a molybdate precursor compound whose crystalline structure isomorphically accommodates Cu2+ and Co2+ cations in a wide range of compositions. As revealed by energy-dispersive X-ray nanospectroscopy and temperature-resolved X-ray diffraction, superior mixing of Cu and Co species promotes formation of CuCo alloy nanocrystals after activation, leading to two orders of magnitude higher yield to high alcohols than a benchmark CuCoCr catalyst. Substantiating simulations, the yield to high alcohols is maximized in parallel to the CuCo alloy contribution, for Co-rich surface compositions, for which Cu phase segregation is prevented. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microbiological Safety of Chicken Litter or Chicken Litter-Based Organic Fertilizers: A Review

Abstract: Chicken litter or chicken litter-based organic fertilizers are usually recycled into the soil to improve the structure and fertility of agricultural land. As an important source of nutrients for crop production, chicken litter may also contain a variety of human pathogens that can threaten humans who consume the contaminated food or water. Composting can inactivate pathogens while creating a soil amendment beneficial for application to arable agricultural land. Some foodborne pathogens may have the potential to survive for long periods of time in raw chicken litter or its composted products after land application, and a small population of pathogenic cells may even regrow to high levels when the conditions are favorable for growth. Thermal processing is a good choice for inactivating pathogens in chicken litter or chicken litter-based organic fertilizers prior to land application. However, some populations may become acclimatized to a hostile environment during build-up or composting and develop heat resistance through cross-protection during subsequent high temperature treatment. Therefore, this paper reviews currently available information on the microbiological safety of chicken litter or chicken litter-based organic fertilizers, and discusses about further research on developing novel and effective disinfection techniques, including physical, chemical, and biological treatments, as an alternative to current methods.

Detecting periods of eating during free-living by tracking wrist motion.

Abstract: This paper is motivated by the growing prevalence of obesity, a health problem affecting over 500 million people. Measurements of energy intake are commonly used for the study and treatment of obesity. However, the most widely used tools rely upon self-report and require a considerable manual effort, leading to underreporting of consumption, noncompliance, and discontinued use over the long term. The purpose of this paper is to describe a new method that uses a watch-like configuration of sensors to continuously track wrist motion throughout the day and automatically detect periods of eating. Our method uses the novel idea that meals tend to be preceded and succeeded by the periods of vigorous wrist motion. We describe an algorithm that segments and classifies such periods as eating or noneating activities. We also evaluate our method on a large dataset (43 subjects, 449 total h of data, containing 116 periods of eating) collected during free-living. Our results show an accuracy of 81% for detecting eating at 1-s resolution in comparison to manually marked event logs of periods eating. These results indicate that vigorous wrist motion is a useful indicator for identifying the boundaries of eating activities, and that our method should prove useful in the continued development of body-worn sensor tools for monitoring energy intake.

Toward Structurally Defined Carbon Dots as Ultracompact Fluorescent Probes

Abstract: There has been much discussion on the need to develop fluorescent quantum dots (QDs) as ultracompact probes, with overall size profiles comparable to those of the genetically encoded fluorescent tags. In the use of conventional semiconductor QDs for such a purpose, the beautifully displayed dependence of fluorescence color on the particle diameter becomes a limitation. More recently, carbon dots have emerged as a new platform of QD-like fluorescent nanomaterials. The optical absorption and fluorescence emissions in carbon dots are not bandgap in origin, different from those in conventional semiconductor QDs. The absence of any theoretically defined fluorescence color - dot size relationships in carbon dots may actually be exploited as a unique advantage in the size reduction toward having carbon dots serve as ultracompact QD-like fluorescence probes. Here we report on carbon dots of less than 5 nm in the overall dot diameter with the use of 2,2′-(ethylenedioxy)bis(ethylamine) (EDA) molecules for the carbo...

Chemically tailoring coal to fluorescent carbon dots with tuned size and their capacity for Cu(II) detection.

Abstract: The desired control of size, structure, and optical properties of fluorescent carbon dots (CDs) is critical for understanding the fluorescence mechanism and exploring their potential application. Herein, a top-down strategy to chemically tailor the inexpensive coal to fluorescent CDs by a combined method of carbonization and acidic oxidation etching is reported. The size and optical properties of the as-made CDs are tuned by controlling the structures of graphitic crystallites in the starting precursor. The coal-derived CDs exhibit two different distinctive emission modes, where the intensity of the short-wavelength emission is significantly enhanced by partial reduction treatment. The evolution of the electronic structure and the surface states analysis show that two different types of fluorescence centers, nano-sized sp(2) carbon domains and surface defects, are responsible for the observed emission characteristics. The reduced CDs are demonstrated as an effective fluorescent sensing material for label-free and selective detection of Cu(II) ions with a detection limit as low as 2.0 nM, showing a great promise for real-world sensor applications.