Showing papers by "Florida Atlantic University published in 2012"

Customer engagement, buyer‐seller relationships, and social media

Abstract: Purpose – The advent of the internet and in particular the interactive features of Web 2.0 in recent years have led to an explosion of interest in customer engagement. The opportunities presented by social media to help build close relationships with customers seem to have excited practitioners in a wide variety of industries worldwide. Academic scholarship on customer engagement, however, has lagged practice and its theoretical foundation is relatively underdeveloped and a better understanding of the concept is essential to develop strategies for customer engagement. This paper seeks to address some of these issues.Design/methodology/approach – The paper attempts to enhance understanding of customer engagement by examining practitioner views of customer engagement, linking it to the marketing concept, market orientation, and relationship marketing, modeling the customer engagement cycle, and developing a customer engagement matrix.Findings – The paper develops a model of the customer engagement cycle wit...

Signaling in Equity Crowdfunding

Abstract: This paper presents an initial empirical examination of which start-up signals will induce small investors to commit financial resources in an equity crowdfunding context. We examine the impact of firms’ financial roadmaps (e.g., preplanned exit strategies such as IPOs or acquisitions), external certification (awards, government grants and patents), internal governance (such as board structure), and risk factors (such as amount of equity offered and the presence of disclaimers) on fundraising success. Our data highlight the importance of financial roadmaps and risk factors, as well as internal governance, for successful equity crowdfunding. External certification, by contrast, has little or no impact on success. We also discuss the implications for successful policy design.

Resolution of ray-finned fish phylogeny and timing of diversification

Abstract: Ray-finned fishes make up half of all living vertebrate species. Nearly all ray-finned fishes are teleosts, which include most commercially important fish species, several model organisms for genomics and developmental biology, and the dominant component of marine and freshwater vertebrate faunas. Despite the economic and scientific importance of ray-finned fishes, the lack of a single comprehensive phylogeny with corresponding divergence-time estimates has limited our understanding of the evolution and diversification of this radiation. Our analyses, which use multiple nuclear gene sequences in conjunction with 36 fossil age constraints, result in a well-supported phylogeny of all major ray-finned fish lineages and molecular age estimates that are generally consistent with the fossil record. This phylogeny informs three long-standing problems: specifically identifying elopomorphs (eels and tarpons) as the sister lineage of all other teleosts, providing a unique hypothesis on the radiation of early euteleosts, and offering a promising strategy for resolution of the “bush at the top of the tree” that includes percomorphs and other spiny-finned teleosts. Contrasting our divergence time estimates with studies using a single nuclear gene or whole mitochondrial genomes, we find that the former underestimates ages of the oldest ray-finned fish divergences, but the latter dramatically overestimates ages for derived teleost lineages. Our time-calibrated phylogeny reveals that much of the diversification leading to extant groups of teleosts occurred between the late Mesozoic and early Cenozoic, identifying this period as the “Second Age of Fishes.”

Dual language exposure and early bilingual development

Abstract: The extant literature includes conflicting assertions regarding the influence of bilingualism on the rate of language development. The present study compared the language development of equivalently high-SES samples of bilingually and monolingually developing children from 1 ; 10 to 2 ; 6. The monolingually developing children were significantly more advanced than the bilingually developing children on measures of both vocabulary and grammar in single language comparisons, but they were comparable on a measure of total vocabulary. Within the bilingually developing sample, all measures of vocabulary and grammar were related to the relative amount of input in that language. Implications for theories of language acquisition and for understanding bilingual development are discussed.

Inhibition of natural antisense transcripts in vivo results in gene-specific transcriptional upregulation

Abstract: The ability to specifically upregulate genes in vivo holds great therapeutic promise. Here we show that inhibition or degradation of natural antisense transcripts (NATs) by single-stranded oligonucleotides or siRNAs can transiently and reversibly upregulate locus-specific gene expression. Brain-derived neurotrophic factor (BDNF) is normally repressed by a conserved noncoding antisense RNA transcript, BDNF-AS. Inhibition of this transcript upregulates BDNF mRNA by two- to sevenfold, alters chromatin marks at the BDNF locus, leads to increased protein levels and induces neuronal outgrowth and differentiation both in vitro and in vivo. We also show that inhibition of NATs leads to increases in glial-derived neurotrophic factor (GDNF) and ephrin receptor B2 (EPHB2) mRNA. Our data suggest that pharmacological approaches targeting NATs can confer locus-specific gene upregulation effects.

Managing Employee Compliance with Information Security Policies: The Critical Role of Top Management and Organizational Culture

Abstract: We develop an individual behavioral model that integrates the role of top management and organizational culture into the theory of planned behavior in an attempt to better understand how top management can influence security compliance behavior of employees. Using survey data and structural equation modeling, we test hypotheses on the relationships among top management participation, organizational culture, and key determinants of employee compliance with information security policies. We find that top management participation in information security initiatives has significant direct and indirect influences on employees’ attitudes towards, subjective norm of, and perceived behavioral control over compliance with information security policies. We also find that the top management participation strongly influences organizational culture which in turn impacts employees’ attitudes towards and perceived behavioral control over compliance with information security policies. Furthermore, we find that the effects of top management participation and organizational culture on employee behavioral intentions are fully mediated by employee cognitive beliefs about compliance with information security policies. Our findings extend information security research literature by showing how top management can play a proactive role in shaping employee compliance behavior in addition to the deterrence oriented remedies advocated in the extant literature. Our findings also refine the theories about the role of organizational culture in shaping employee compliance behavior. Significant theoretical and practical implications of these findings are discussed.

Infants deploy selective attention to the mouth of a talking face when learning speech

Abstract: The mechanisms underlying the acquisition of speech-production ability in human infancy are not well understood. We tracked 4–12-mo-old English-learning infants’ and adults’ eye gaze while they watched and listened to a female reciting a monologue either in their native (English) or nonnative (Spanish) language. We found that infants shifted their attention from the eyes to the mouth between 4 and 8 mo of age regardless of language and then began a shift back to the eyes at 12 mo in response to native but not nonnative speech. We posit that the first shift enables infants to gain access to redundant audiovisual speech cues that enable them to learn their native speech forms and that the second shift reflects growing native-language expertise that frees them to shift attention to the eyes to gain access to social cues. On this account, 12-mo-old infants do not shift attention to the eyes when exposed to nonnative speech because increasing native-language expertise and perceptual narrowing make it more difficult to process nonnative speech and require them to continue to access redundant audiovisual cues. Overall, the current findings demonstrate that the development of speech production capacity relies on changes in selective audiovisual attention and that this depends critically on early experience.

Religion and Stock Price Crash Risk

Abstract: This study examines whether religiosity at the county level is associated with future stock price crash risk. We find robust evidence that firms headquartered in counties with higher levels of religiosity exhibit lower levels of future stock price crash risk. This finding is consistent with the view that religion, as a set of social norms, helps to curb bad news hoarding activities by managers. Our evidence further shows that religiosity is more salient in curbing bad news hoarding for riskier firms and firms with weak governance mechanisms. Specifically, we find that the negative relation between religiosity and stock price crash risk is stronger (more negative) for riskier firms and for firms with weaker corporate governance monitoring mechanisms as measured by shareholder takeover rights and dedicated institutional ownership.

Historical ecology with real numbers: past and present extent and biomass of an imperilled estuarine habitat

Abstract: Historic baselines are important in developing our understanding of ecosystems in the face of rapid global change. While a number of studies have sought to determine changes in extent of exploited habitats over historic timescales, few have quantified such changes prior to late twentieth century baselines. Here, we present, to our knowledge, the first ever large-scale quantitative assessment of the extent and biomass of marine habitat-forming species over a 100-year time frame. We examined records of wild native oyster abundance in the United States from a historic, yet already exploited, baseline between 1878 and 1935 (predominantly 1885–1915), and a current baseline between 1968 and 2010 (predominantly 2000–2010). We quantified the extent of oyster grounds in 39 estuaries historically and 51 estuaries from recent times. Data from 24 estuaries allowed comparison of historic to present extent and biomass. We found evidence for a 64 per cent decline in the spatial extent of oyster habitat and an 88 per cent decline in oyster biomass over time. The difference between these two numbers illustrates that current areal extent measures may be masking significant loss of habitat through degradation.

Multilevel models in international business research

Abstract: Multiple-level (or mixed linear) modeling (MLM) can simultaneously test hypotheses at several levels of analysis (usually two or three), or control for confounding effects at one level while testing hypotheses at others. Advances in multi-level modeling allow increased precision in quantitative international business (IB) research, and open up new methodological and conceptual possibilities. However, they create new challenges, and they are still not frequently used in IB research. In this editorial we outline some key methodological issues for the uses of MLM in IB, including criteria, sample size, and measure equivalence issues. We then examine promising directions for future multilevel IB research considering comparative opportunities at nation, multiple-nation cluster, and within-nation region levels, including large multilevel databases. We also consider its promise for MNE research about semi-globalization, interorganizational effects across nations, clusters within nations, and teams and subsidiaries within MNEs.

Risk Factors for Anterior Cruciate Ligament Injury A Review of the Literature — Part 1: Neuromuscular and Anatomic Risk

Abstract: Context: Injuries to the anterior cruciate ligament (ACL) of the knee are immediately debilitating and can cause long-term consequences, including the early onset of osteoarthritis It is important to have a comprehensive understanding of all possible risk factors for ACL injury to identify individuals who are at risk for future injuries and to provide an appropriate level of counseling and programs for preventionObjective: This review, part 1 of a 2-part series, highlights what is known and still unknown regarding anatomic and neuromuscular risk factors for injury to the ACL from the current peer-reviewed literatureData Sources: Studies were identified from MEDLINE (1951–March 2011) using the MeSH terms anterior cruciate ligament, knee injury, and risk factors The bibliographies of relevant articles and reviews were cross-referenced to complete the searchStudy Selection: Prognostic studies that utilized the case-control and prospective cohort study designs to evaluate risk factors for ACL injury were included in this reviewResults: A total of 50 case-control and prospective cohort articles were included in the review, and 30 of these studies focused on neuromuscular and anatomic risk factorsConclusions: Several anatomic and neuromuscular risk factors are associated with increased risk of suffering ACL injury—such as female sex and specific measures of bony geometry of the knee joint, including decreased intercondylar femoral notch size, decreased depth of concavity of the medial tibial plateau, increased slope of the tibial plateaus, and increased anterior-posterior knee laxity These risk factors most likely act in combination to influence the risk of ACL injury; however, multivariate risk models that consider all the aforementioned risk factors in combination have not been established to explore this interaction

Parent-child communication during adolescence

Abstract: Conventional wisdom regards parent-adolescent communication as an oxymoron. As is often the case with adolescence, however, conventional wisdom can be misleading. Although communication during the adolescent years certainly is a challenge for parents and children, this challenge stems primarily from the changing nature of the relationship, not from an inherent inability of adolescents and parents to engage in meaningful conversation (for recent reviews, see Laursen & Collins, 2009; Smetana, Campione-Barr, & Metzger, 2006). As families navigate the transition from childhood into adulthood, the frequency and content of their interactions change. Increasing adolescent autonomy inevitably alters patterns of self-disclosure, shared experiences, and perceptions of privacy and responsibilities. Yet even in the face of these significant alterations, familial emotional bonds are noteworthy for their resilience and continuity. To the extent that there is a generation gap, it is as much a product of incongruentperceptions and expectations as it is of inadequate or insufficient conversation (Steinberg, 2001). Parents and adolescents do not necessarily share the same view of the relationship and their ability to communicate, nor are their perspectives typically congruent with those of observers outside the relationship. Parents and adolescents pursue different implicit goals and timetables regarding the adolescent’s autonomy, which may give rise to communication difficulties (Collins & Laursen, 2004). But families differ widely in the extent to which autonomy has a corrosive effect on parent-child communication. For some it is a difficult passage, but most families are well equipped to navigate the developmental challenges of adolescence. This chapter will describe how patterns of parent-child communication are trans-formed across adolescence years in terms of changes in the nature and functions of relationships. We will focus on salient aspects of parent-adolescent relationships that best illustrate alterations in patterns of communication. The chapter is divided into five sections. The first section provides an overview of theoretical accounts of parent-child relationships during adolescence. Most models of development assume perturbations in family relationships during the adolescent years, although there is less agreement as to the implications for family communication. The second section describes continuity and change in manifestations of parent-adolescent closeness. For most families, closeness and interdependence decline across adolescence, but the fall-off in intimatecommunication appears to be especially pronounced for those in troubled relationships. The third section describes continuity and change in manifestations of parent-adolescent conflict. Expressions of anger and coercion may increase during the transition from childhood to adolescence, particularly among families with prior communication difficulties, but strife is not a normative feature of this age period. The fourth section describes continuity and change in manifestations of parent-adolescent monitoring and information management. Parental control of adolescents’ unsupervised activities may increasingly threaten adolescents’ growing needs for autonomy, and parents need to provide an emotional climate in which adolescents voluntarily disclose information about their activities and whereabouts. The concluding remarks place changing patterns of parentadolescent communication in the larger context of relationship transformations from childhood to adulthood.

Potentially avoidable hospitalizations of dually eligible Medicare and Medicaid beneficiaries from nursing facility and Home- and Community-Based Services waiver programs.

Abstract: Objectives: Beneficiaries dually eligible for Medicare and Medicaid are of increasing interest because of their clinical complexity and high costs. The objective of this study was to examine the incidence, costs, and factors associated with potentially avoidable hospitalizations (PAH) in this population. Design: Retrospective study of hospitalizations. Setting: Hospitalizations from nursing facilities (NF) including Medicare and Medicaid-covered stays, and Medicaid Home and Community-Based Services (HCBS) waiver programs. Participants: Dually eligible individuals who received Medicare skilled nursing facility (SNF) or Medicaid NF services or HCBS waiver services in 2005. Interventions: None. Measurements: Potentiall avoidable hospitalizations were defined by an expert panel that identified conditions and associated Diagnostic Related Groups (DRGs) which can often be prevented or safely and effectively managed without hospitalization. Results: More than one-third of the population was hospitalized at least once, totaling almost 1 million hospitalizations. The admitting DRG for 382,846 (39%) admissions were identified as PAH. PAH rates varied considerably among states, and blacks had a higher rate and costs for PAH than whites. Five conditions (pneumonia, congestive heart failure, urinary tract infections, dehydration, and chronic obstructive pulmonary disease/asthma) were responsible for 78% of the PAH. The total Medicare costs for these hospitalizations were $3 billion, but only $463 million for Medicaid. A sensitivity analysis, assuming that 20%�60% of these hospitalizations could be prevented, revealed that between 77,000 and 260,000 hospitalizations and between $625 million and $1.9 billion in expenditures could be avoided annually in this population. Conclusion: Potentially avoidable hospitalizations are common and costly in the dually eligible population. New initiatives are needed to reduce PAH in this population as they are costly and can adversely affect function and quality of life.

Noiseonomics: The relationship between ambient noise levels in the sea and global economic trends

Abstract: In recent years, the topic of noise in the sea and its effects on marine mammals has attracted considerable attention from both the scientific community and the general public. Since marine mammals rely heavily on acoustics as a primary means of communicating, navigating, and foraging in the ocean, any change in their acoustic environment may have an impact on their behavior. Specifically, a growing body of literature suggests that low-frequency, ambient noise levels in the open ocean increased approximately 3.3 dB per decade during the period 1950–2007. Here we show that this increase can be attributed primarily to commercial shipping activity, which in turn, can be linked to global economic growth. As a corollary, we conclude that ambient noise levels can be directly related to global economic conditions. We provide experimental evidence supporting this theory and discuss its implications for predicting future noise levels based on global economic trends.

Income diversification and risk: Does ownership matter? An empirical examination of Indian banks

Abstract: We examine the impact of ownership on income diversification and risk for Indian banks over the period 2001–2009. We investigate both the determinants of non-interest income and the impact of diversification on various profitability and insolvency risk measures for public sector, private domestic, and foreign banks. We document that ownership does matter in the pursuit of non-interest income. Relative to private domestic banks, public sector banks earn significantly less fee-income, while foreign banks report higher fee income. Public sector banks with higher levels of governmental ownership are significantly less likely to pursue non-interest income sources. Fee-based income significantly reduces risk, measured by profitability variables, for public sector banks. Default risk is also reduced for these banks. From a regulatory perspective, it appears that diversification benefits India’s public sector banks. Our research has implications for the changes in the risk profile for banks in emerging banking markets pursuing non-interest revenue sources.

Cyberbullying: Neither an epidemic nor a rarity

Abstract: There appears to be some perceptual confusion with regard to the scope and extent of online bullying based on media reports and a number of studies—some of which are theoretically sound and methodologically rigorous and some of which are not. In the following text, we share findings from our own research and those of our peers to highlight the actual prevalence rates of cyberbullying. We also depict an overlap between offline and online bullying based on empirical works to make clear that those who are mistreated in the real world and in cyberspace are not two separate populations. Finally, we champion the systemic approach of enhancing the emotional and relational climate within schools as the most promising way to stem the tide of adolescent aggression.

The impact of education, experience and inner circle advisors on SME performance: insights from a study of public development centers

Abstract: In this study, we investigate the effects of entrepreneurial human capital on SME performance using data on 2,713 SMEs within the European Union. Performance was measured in two ways: profitability as ROA and productivity as revenue per employee. Results indicate that both profitability and productivity are positively related to industry-specific knowledge possessed by the CEO-owner prior to starting up the firm and the general business knowledge acquired once the firm is up and running. Experience as a result of having previously worked in a firm in the same industry before starting a business was related to productivity, but there is no relation with profitability. There is a link between performance and inclusion of other CEO-owners in the founder’s inner circle of advisors. This relationship is positive when the advisor’s venture has experienced failure and negative when the advisor’s venture has been successful. We discuss the significance of these findings for research and practice.

Risk Factors for Anterior Cruciate Ligament Injury A Review of the Literature—Part 2: Hormonal, Genetic, Cognitive Function, Previous Injury, and Extrinsic Risk Factors

Abstract: Context: Injuries to the anterior cruciate ligament (ACL) are immediately disabling and are associated with long-term consequences, such as posttraumatic osteoarthritis. It is important to have a comprehensive understanding of all possible risk factors for ACL injury to identify individuals who are at risk for future injuries and to provide an appropriate level of counseling and programs for prevention.Objective: This review, part 2 of a 2-part series, highlights what is known and still unknown regarding hormonal, genetic, cognitive function, previous injury, and extrinsic risk factors for ACL injury.Data Sources: Studies were identified from MEDLINE (1951–March 2011) using the MeSH terms anterior cruciate ligament, knee injury, and risk factors. The bibliographies of relevant articles and reviews were cross-referenced to complete the search.Study Selection: Prognostic case-control and prospective cohort study designs to evaluate risk factors for ACL injury were included in this review.Results: A total of 50 case-control and prospective cohort articles were included in parts 1 and 2. Twenty-one focused on hormonal, genetic, cognitive function, previous injury, and extrinsic risk factors.Conclusions: Several risk factors are associated with increased risk of suffering ACL injury—such as female sex, prior reconstruction of the ACL, and familial predisposition. These risk factors most likely act in combination with the anatomic factors reviewed in part 1 of this series to influence the risk of suffering ACL injury.

Thinking through the Body: Essays in Somaesthetics

Abstract: This book provides a richly rewarding vision of the burgeoning interdisciplinary field of somaesthetics. Composed of fourteen wide-ranging but finely integrated essays by Richard Shusterman, the originator of the field, Thinking through the Body explains the philosophical foundations of somaesthetics and applies its insights to central issues in ethics, education, cultural politics, consciousness studies, sexuality and the arts. Integrating Western philosophy, cognitive science and somatic methodologies with classical Asian theories of body, mind and action, these essays probe the nature of somatic existence and the role of body consciousness in knowledge, memory and behavior. Deploying somaesthetic perspectives to analyze key aesthetic concepts (such as style and the sublime), he offers detailed studies of embodiment in drama, dance, architecture and photography. The volume also includes somaesthetic exercises for the classroom and explores the ars erotica as an art of living.

Mapping Individual Tree Species in an Urban Forest Using Airborne Lidar Data and Hyperspectral Imagery

Abstract: We developed a neural network based approach to identify urban tree species at the individual tree level from lidar and hyperspectral imagery. This approach is capable of modeling the characteristics of multiple spectral signatures within each species using an internally unsupervised engine, and is able to catch spectral differences between species using an externally supervised system. To generate a species-level map for an urban forest with high spatial heterogeneity and species diversity, we conducted a treetop-based species identification. This can avoid the problems of double-sided illumination, shadow, and mixed pixels, encountered in the crown-based species classification. The study indicates lidar data in conjunction with hyperspectral imagery are not only capable of detecting individual trees and estimating their tree metrics, but also identifying their species types using the developed algorithm. The integration of these two data sources has great potential to take the place of traditional field surveys.

Compact implementation and performance evaluation of block ciphers in ATtiny devices

Abstract: The design of lightweight block ciphers has been a very active research topic over the last years. However, the lack of comparative source codes generally makes it hard to evaluate the extent to which implementations of different ciphers actually reach their low-cost goals on various platforms. This paper reports on an initiative aiming to relax this issue. First, we provide implementations of 12 block ciphers on an ATMEL AVR ATtiny45 8-bit microcontroller, and make the corresponding source code available on a web page. All implementations are made public under an open-source license. Common interfaces and design goals are followed by all designers to achieve comparable implementation results. Second, we evaluate performance figures of our implementations with respect to different metrics, including energy-consumption measurements and show our improvements compared to existing implementations.

Beyond the blank slate: routes to learning new coordination patterns depend on the intrinsic dynamics of the learner—experimental evidence and theoretical model

Abstract: Using an approach that combines experimental studies of bimanual movements to visual stimuli and theoretical modeling, the present paper develops a dynamical account of sensorimotor learning, that is, how new skills are acquired and old ones modified. A significant aspect of our approach is the focus on the individual learner as the basic unit of analysis, in particular the quantification of predispositions and capabilities that the individual learner brings to the learning environment. Such predispositions constitute the learner’s behavioral repertoire, captured here theoretically as a dynamical landscape (‘intrinsic dynamics’). The learning process is demonstrated to not only lead to a relatively permanent improvement of performance in the required task —the usual outcome— but also to alter the individual’s entire repertoire. Changes in the dynamical landscape due to learning are shown to result from two basic mechanisms or “routes”: bifurcation and shift. Which mechanism is selected depends both on the initial individual repertoire before new learning begins and the task to be learned. Both bifurcation and shift mechanisms are accommodated by a dynamical model, a relatively straightforward development of the well-established HKB model of movement coordination. Model simulations show that although environmental or task demands may be met equally well using either mechanism, the bifurcation route results in greater stabilization of the to-be-learned behavior. Thus stability not (or not only) error is demonstrated to be the basis of selection, both of a new pattern of behavior and the path (smooth shift versus abrupt qualitative change) that learning takes. In line with these results, recent neurophysiological evidence indicates that stability is a relevant feature around which brain activity is organized while an individual performs a coordination task. Finally, we explore the consequences of the dynamical approach to learning for theories of biological change.

Splice variant of the SND1 transcription factor is a dominant negative of SND1 members and their regulation in Populus trichocarpa

Abstract: Secondary Wall-Associated NAC Domain 1s (SND1s) are transcription factors (TFs) known to activate a cascade of TF and pathway genes affecting secondary cell wall biosynthesis (xylogenesis) in Arabidopsis and poplars. Elevated SND1 transcriptional activation leads to ectopic xylogenesis and stunted growth. Nothing is known about the upstream regulators of SND1. Here we report the discovery of a stem-differentiating xylem (SDX)-specific alternative SND1 splice variant, PtrSND1-A2IR, that acts as a dominant negative of SND1 transcriptional network genes in Populus trichocarpa. PtrSND1-A2IR derives from PtrSND1-A2, one of the four fully spliced PtrSND1 gene family members (PtrSND1-A1, -A2, -B1, and -B2). Each full-size PtrSND1 activates its own gene, and all four full-size members activate a common MYB gene (PtrMYB021). PtrSND1-A2IR represses the expression of its PtrSND1 member genes and PtrMYB021. Repression of the autoregulation of a TF family by its only splice variant has not been previously reported in plants. PtrSND1-A2IR lacks DNA binding and transactivation abilities but retains dimerization capability. PtrSND1-A2IR is localized exclusively in cytoplasmic foci. In the presence of any full-size PtrSND1 member, PtrSND1-A2IR is translocated into the nucleus exclusively as a heterodimeric partner with full-size PtrSND1s. Our findings are consistent with a model in which the translocated PtrSND1-A2IR lacking DNA-binding and transactivating abilities can disrupt the function of full-size PtrSND1s, making them nonproductive through heterodimerization, and thereby modulating the SND1 transcriptional network. PtrSND1-A2IR may contribute to transcriptional homeostasis to avoid deleterious effects on xylogenesis and plant growth.

Stress and Coping in Women Living with HIV: A Meta-Analytic Review

Abstract: To examine effects between stressors and coping mechanisms on behavioral health outcomes a meta-analysis was conducted using forty empirical articles which sampled 7,602 adult women living with HIV/AIDS in the U.S. (M = 36.3 years). Three independent reviewers conducted searches in abstract databases from 1997 to present day. Articles reporting effect sizes amongst psychosocial stressors and coping mechanisms with indices of behavioral/mental health were selected. The meta-analyses revealed that in a time frame characterized by the widespread availability of anti-retroviral medication, poor mental health outcomes were predicted, in a similar manner, by psychosocial stress and HIV/AIDS symptomology. Significant effects were also observed with functional impairment, though to a lesser degree. Coping by avoidance and social isolation predicted more severe mental health outcomes. Spirituality and positive reappraisal predicted greater psychological adaptation than did social support seeking. Despite advancements in anti-retroviral treatment for women, HIV/AIDS symptoms and acute and/or chronic psychosocial stress pose the same threat to behavioral and mental health. In the face of these stressors, positive reframing appears to promote psychological adaptation in a way which may lead to positive health outcomes in women living with HIV/AIDS.

An Efficient Prediction-Based Routing in Disruption-Tolerant Networks

Abstract: Routing is one of the most challenging, open problems in disruption-tolerant networks (DTNs) because of the short-lived wireless connectivity environment. To deal with this issue, researchers have investigated routing based on the prediction of future contacts, taking advantage of nodes' mobility history. However, most of the previous work focused on the prediction of whether two nodes would have a contact, without considering the time of the contact. This paper proposes predict and relay (PER), an efficient routing algorithm for DTNs, where nodes determine the probability distribution of future contact times and choose a proper next-hop in order to improve the end-to-end delivery probability. The algorithm is based on two observations: one is that nodes usually move around a set of well-visited landmark points instead of moving randomly; the other is that node mobility behavior is semi-deterministic and could be predicted once there is sufficient mobility history information. Specifically, our approach employs a time-homogeneous semi-Markov process model that describes node mobility as transitions between landmarks. Then, we extend it to handle the scenario where we consider the transition time between two landmarks. A simulation study shows that this approach improves the delivery ratio and also reduces the delivery latency compared to traditional DTN routing schemes.

A review of the stability of feature selection techniques for bioinformatics data

Abstract: Feature selection is an important step in data mining and is used in various domains including genetics, medicine, and bioinformatics. Choosing the important features (genes) is essential for the discovery of new knowledge hidden within the genetic code as well as the identification of important biomarkers. Although feature selection methods can help sort through large numbers of genes based on their relevance to the problem at hand, the results generated tend to be unstable and thus cannot be reproduced in other experiments. Relatedly, research interest in the stability of feature ranking methods has grown recently and researchers have produced experimental designs for testing the stability of feature selection, creating new metrics for measuring stability and new techniques designed to improve the stability of the feature selection process. In this paper, we will introduce the role of stability in feature selection with DNA microarray data. We list various ways of improving feature ranking stability, and discuss feature selection techniques, specifically explaining ensemble feature ranking and presenting various ensemble feature ranking aggregation methods. Finally, we discuss experimental procedures such as dataset perturbation, fixed overlap partitioning, and cross validation procedures that help researchers analyze and measure the stability of feature ranking methods. Throughout this work, we investigate current research in the field and discuss possible avenues of continuing such research efforts.