Showing papers by "University of Memphis published in 2013"

Mobile computing devices in higher education: Student perspectives on learning with cellphones, smartphones & social media

Abstract: The purpose of this research was to explore teaching and learning when mobile computing devices, such as cellphones and smartphones, were implemented in higher education. This paper presents a portion of the findings on students' perceptions of learning with mobile computing devices and the roles social media played. This qualitative research study focused on students from three universities across the US. The students' teachers had been integrating mobile computing devices, such as cellphones and smartphones, into their courses for at least two semesters. Data were collected through student focus group interviews. Two specific themes emerged from the interview data: (a) advantages of mobile computing devices for student learning and (b) frustrations from learning with mobile computing devices. Mobile computing devices and the use of social media created opportunities for interaction, provided opportunities for collaboration, as well as allowed students to engage in content creation and communication using social media and Web 2.0 tools with the assistance of constant connectivity.

NLSR: named-data link state routing protocol

Abstract: This paper presents the design of the Named-data Link State Routing protocol (NLSR), a routing protocol for Named Data Networking (NDN). Since NDN uses names to identify and retrieve data, NLSR propagates reachability to name prefixes instead of IP prefixes. Moreover, NLSR differs from IP-based link-state routing protocols in two fundamental ways. First, NLSR uses Interest/Data packets to disseminate routing updates, directly benefiting from NDN's data authenticity. Second, NLSR produces a list of ranked forwarding options for each name prefix to facilitate NDN's adaptive forwarding strategies. In this paper we discuss NLSR's main design choices on (1) a hierarchical naming scheme for routers, keys, and routing updates, (2) a hierarchical trust model for routing within a single administrative domain, (3) a hop-by-hop synchronization protocol to replace the traditional network-wide flooding for routing update dissemination, and (4) a simple way to rank multiple forwarding options. Compared with IP-based link state routing, NLSR offers more efficient update dissemination, built-in update authentication, and native support of multipath forwarding.

The effects of social- and self-motives on the intentions to share positive and negative word of mouth

Abstract: We examine social- and self-motives as drivers of Word of Mouth (WOM). The main proposition is that the transmitter expects to gain personal and social benefits from sharing his opinion about a brand. The gains are in the form of expected satisfaction of self- and social-needs. In the research model, self-needs (i.e., self-enhancement and self-affirmation) are considered the initial driver of WOM. The desire for their satisfaction through WOM results in an intended social interaction, which in turn triggers social-motives: social-needs (i.e., social comparison and social bonding) and social-intentions (i.e., helping others and providing social information). WOM is the outcome of the intention to engage in a social interaction that is initiated by the intention to satisfy self-needs. Through an empirical analysis, we examine how the underlying mechanism varies for positive and negative WOM. Positive WOM is motivated primarily by the need for self-enhancement, and negative WOM is motivated by the need for self-affirmation. The need for social comparison affects both valences of WOM, the need for social bonding affects only positive WOM, and intention to help others and share social information affect only negative WOM. The findings suggest that discussing brands can be a mechanism for acquiring personal and social benefits, and consequently, promotional campaigns should highlight the gains customers accrue through WOM.

Perceived organizational support and embeddedness as key mechanisms connecting socialization tactics to commitment and turnover among new employees

Abstract: Summary Retention of new hires is a critical issue for organizations. We propose that relationships are important mechanisms through which socialization tactics influence commitment and turnover. The key theoretical mechanisms connecting socialization tactics to turnover in our model are the extent to which newcomers perceive their relationship with the organization as supportive, caring, and entailing positive social exchanges and the extent to which newcomers become embedded within the organization. We collected longitudinal data from over 500 employees over the first year of employment. Consistent with our hypotheses, socialization tactics influence perceived organizational support (POS) and job embeddedness, and POS and embeddedness both relate to organizational commitment and voluntary turnover. Results support POS and embeddedness as relational mechanisms that bind employees to the organization as a result of socialization tactics. Copyright © 2012 John Wiley & Sons, Ltd.

AutoTutor and affective autotutor: Learning by talking with cognitively and emotionally intelligent computers that talk back

Abstract: We present AutoTutor and Affective AutoTutor as examples of innovative 21st century interactive intelligent systems that promote learning and engagement. AutoTutor is an intelligent tutoring system that helps students compose explanations of difficult concepts in Newtonian physics and enhances computer literacy and critical thinking by interacting with them in natural language with adaptive dialog moves similar to those of human tutors. AutoTutor constructs a cognitive model of students' knowledge levels by analyzing the text of their typed or spoken responses to its questions. The model is used to dynamically tailor the interaction toward individual students' zones of proximal development. Affective AutoTutor takes the individualized instruction and human-like interactivity to a new level by automatically detecting and responding to students' emotional states in addition to their cognitive states. Over 20 controlled experiments comparing AutoTutor with ecological and experimental controls such reading a textbook have consistently yielded learning improvements of approximately one letter grade after brief 30--60-minute interactions. Furthermore, Affective AutoTutor shows even more dramatic improvements in learning than the original AutoTutor system, particularly for struggling students with low domain knowledge. In addition to providing a detailed description of the implementation and evaluation of AutoTutor and Affective AutoTutor, we also discuss new and exciting technologies motivated by AutoTutor such as AutoTutor-Lite, Operation ARIES, GuruTutor, DeepTutor, MetaTutor, and AutoMentor. We conclude this article with our vision for future work on interactive and engaging intelligent tutoring systems.

Very Fast Money: High-Frequency Trading on the NASDAQ

Abstract: This paper provides evidence regarding high-frequency trader (HFT) trading performance, trading costs, and effects on market efficiency using a sample of NASDAQ trades and quotes that directly identifies HFT participation. I find that HFTs engage in successful intra-day market timing, spreads are wider when HFTs provide liquidity and tighter when HFTs take liquidity, and prices incorporate information from order flow and market-wide returns more efficiently on days when HFT participation is high.

Mobile Health: Revolutionizing Healthcare Through Transdisciplinary Research

Abstract: Mobile health (mHealth) seeks to improve individuals' health and well-being by continuously monitoring their status, rapidly diagnosing medical conditions, recognizing behaviors, and delivering just-in-time interventions, all in the user's natural mobile environment. The Web extra at http://youtu.be/o2mieSywutY is an audio interview in which Santosh Kumar, Wendy Nilsen, and Mani Srivastava discuss the path toward realizing mobile health systems.

Tone Language Speakers and Musicians Share Enhanced Perceptual and Cognitive Abilities for Musical Pitch: Evidence for Bidirectionality between the Domains of Language and Music

Abstract: Psychophysiological evidence suggests that music and language are intimately coupled such that experience/training in one domain can influence processing required in the other domain. While the influence of music on language processing is now well-documented, evidence of language-to-music effects have yet to be firmly established. Here, using a cross-sectional design, we compared the performance of musicians to that of tone-language (Cantonese) speakers on tasks of auditory pitch acuity, music perception, and general cognitive ability (e.g., fluid intelligence, working memory). While musicians demonstrated superior performance on all auditory measures, comparable perceptual enhancements were observed for Cantonese participants, relative to English-speaking nonmusicians. These results provide evidence that tone-language background is associated with higher auditory perceptual performance for music listening. Musicians and Cantonese speakers also showed superior working memory capacity relative to nonmusician controls, suggesting that in addition to basic perceptual enhancements, tone-language background and music training might also be associated with enhanced general cognitive abilities. Our findings support the notion that tone language speakers and musically trained individuals have higher performance than English-speaking listeners for the perceptual-cognitive processing necessary for basic auditory as well as complex music perception. These results illustrate bidirectional influences between the domains of music and language.

What does it mean to "employ" the RE-AIM model?

Abstract: Many grant proposals identify the use of a given evaluation model or framework but offer little about how such models are implemented. The authors discuss what it means to employ a specific model, RE-AIM, and key dimensions from this model for program planning, implementation, evaluation, and reporting. The authors report both conceptual and content specifications for the use of the RE-AIM model and a content review of 42 recent dissemination and implementation grant applications to National Institutes of Health that proposed the use of this model. Outcomes include the extent to which proposals addressed the overall RE-AIM model and specific items within the five dimensions in their methods or evaluation plans. The majority of grants used only some elements of the model (less than 10% contained thorough measures across all RE-AIM dimensions). Few met criteria for “fully developed use” of RE-AIM and the percentage of key issues addressed varied from, on average, 45% to 78% across the RE-AIM dimensions. The...

Mind wandering while reading easy and difficult texts

Abstract: Mind wandering is a phenomenon in which attention drifts away from the primary task to task-unrelated thoughts. Previous studies have used self-report methods to measure the frequency of mind wandering and its effects on task performance. Many of these studies have investigated mind wandering in simple perceptual and memory tasks, such as recognition memory, sustained attention, and choice reaction time tasks. Manipulations of task difficulty have revealed that mind wandering occurs more frequently in easy than in difficult conditions, but that it has a greater negative impact on performance in the difficult conditions. The goal of this study was to examine the relation between mind wandering and task difficulty in a high-level cognitive task, namely reading comprehension of standardized texts. We hypothesized that reading comprehension may yield a different relation between mind wandering and task difficulty than has been observed previously. Participants read easy or difficult versions of eight passages and then answered comprehension questions after reading each of the passages. Mind wandering was reported using the probe-caught method from several previous studies. In contrast to the previous results, but consistent with our hypothesis, mind wandering occurred more frequently when participants read difficult rather than easy texts. However, mind wandering had a more negative influence on comprehension for the difficult texts, which is consistent with the previous data. The results are interpreted from the perspectives of the executive-resources and control-failure theories of mind wandering, as well as with regard to situation models of text comprehension.

Global workspace dynamics: cortical "binding and propagation" enables conscious contents.

Abstract: A global workspace is a hub of binding and propagation in a population of loosely coupled signaling elements. Global workspace (GW) architectures recruit many distributed, specialized agents to help resolve focal ambiguities. In the brain, conscious experiences may reflect a global workspace function. For animals the natural world is full of fitness-related ambiguities, suggesting a general adaptive pressure for brains to resolve focal ambiguities quickly and accurately. In humans and related species the cortico-thalamic (C-T) core is believed to underlie conscious aspects of perception, thinking, learning, feelings of knowing, emotions, imagery, working memory and executive control. The C-T core has many anatomical hubs, but conscious percepts are unitary and internally consistent at any given moment. The repertoire of conscious contents is a large, open set. These points suggest that a brain-based GW capacity cannot be localized in a single anatomical hub. Rather, it should be sought in a dynamic capacity for adaptive binding and propagation of neural signals over multi-hub networks. We refer to this as dynamic global workspace theory (dGW). In this view, conscious contents can arise in any region of the C-T core when multiple signal streams settle on a winner-take-all equilibrium. The resulting bound gestalt may ignite an any-to-many broadcast, lasting ~100-200 ms, and trigger widespread adaptation in established networks. Binding and broadcasting may involve theta/gamma or alpha/gamma phase coupling. Conscious contents (qualia) may reflect their sources in cortex. Sensory percepts may bind and broadcast from posterior regions, while non-sensory feelings of knowing (FOKs) may be frontotemporal. The small focal capacity of conscious contents may be the biological price to pay for global access. We propose that in the intact brain the hippocampal/rhinal complex may support conscious event organization as well as episodic memory coding.

Invited review: the preterm pig as a model in pediatric gastroenterology.

Abstract: At birth, the newborn mammal undergoes a transition from a sterile uterine environment with a constant nutrient supply, to a microbe-rich environment with intermittent oral intake of complex milk nutrients via the gastrointestinal tract (GIT). These functional challenges partly explain the relatively high morbidity and mortality of neonates. Preterm birth interrupts prenatal organ maturation, including that of the GIT, and increases disease risk. Exemplary is necrotizing enterocolitis (NEC), which is associated closely with GIT immaturity, enteral feeding, and bacterial colonization. Infants with NEC may require resection of the necrotic parts of the intestine, leading to short bowel syndrome (SBS), characterized by reduced digestive capacity, fluid loss, and dependency on parenteral nutrition. This review presents the preterm pig as a translational model in pediatric gastroenterology that has provided new insights into important pediatric diseases such as NEC and SBS. We describe protocols for delivery, care, and handling of preterm pigs, and show how the immature GIT responds to delivery method and different nutritional and therapeutic interventions. The preterm pig may also provide a sensitive model for postnatal adaptation of weak term piglets showing high mortality. Attributes of the preterm pig model include close similarities with preterm infants in body size, organ development, and many clinical features, thereby providing a translational advantage relative to rodent models of GIT immaturity. On the other hand, the need for a sow surgical facility, a piglet intensive care unit, and clinically trained personnel may limit widespread use of preterm pigs. Studies on organ adaptation in preterm pigs help to identify the physiological basis of neonatal survival for hypersensitive newborns and aid in defining the optimal diet and rearing conditions during the critical neonatal period.

Self-Efficacy, Competitiveness, and Effort as Antecedents of Salesperson Performance

Abstract: This paper posits and tests a model of the individual characteristics of self-efficacy, competitiveness, and effort as potential antecedents of salesperson performance. Based on two studies in different selling contexts, it is observed that whereas effort mediates the relationship between competitiveness and sales performance, self-efficacy has both direct and indirect effects on sales performance. Structural equation modeling results support the proposed model. Implications and conclusions of the studies are presented.

Examining the role of organizational variables in the salesperson job satisfaction model

Abstract: Job satisfaction has been one of the most studied variables in seeking to understand employee behaviors and attitudes. This has been especially true in sales research because salesperson job satisfaction has been shown to impact a number of key job related attitudes (organizational commitment) and behaviors (potential turnover of salespeople) (Johnston, Parasuraman, Futrell, and Black 1990; Behrman and Perreault 1984). Brown and Peterson (1993) performed a meta-analysis on salesperson job satisfaction that provides an important synthesis of research in this area. Moreover, Brown and Peterson (1994) demonstrated the consistency of several research results concerning key antecedents and consequences of job satisfaction. Importantly, they also point to certain inconclusive findings such as the role of the salesperson performance construct in the job satisfaction model.

Functional flexibility of infant vocalization and the emergence of language

Abstract: We report on the emergence of functional flexibility in vocalizations of human infants. This vastly underappreciated capability becomes apparent when prelinguistic vocalizations express a full range of emotional content—positive, neutral, and negative. The data show that at least three types of infant vocalizations (squeals, vowel-like sounds, and growls) occur with this full range of expression by 3–4 mo of age. In contrast, infant cry and laughter, which are species-specific signals apparently homologous to vocal calls in other primates, show functional stability, with cry overwhelmingly expressing negative and laughter positive emotional states. Functional flexibility is a sine qua non in spoken language, because all words or sentences can be produced as expressions of varying emotional states and because learning conventional “meanings” requires the ability to produce sounds that are free of any predetermined function. Functional flexibility is a defining characteristic of language, and empirically it appears before syntax, word learning, and even earlier-developing features presumed to be critical to language (e.g., joint attention, syllable imitation, and canonical babbling). The appearance of functional flexibility early in the first year of human life is a critical step in the development of vocal language and may have been a critical step in the evolution of human language, preceding protosyntax and even primitive single words. Such flexible affect expression of vocalizations has not yet been reported for any nonhuman primate but if found to occur would suggest deep roots for functional flexibility of vocalization in our primate heritage.

A pattern theory of self

Abstract: I argue for a pattern theory of self as a useful way to organize an interdisciplinary approach to discussions of what constitutes a self. According to the pattern theory, a self is constituted by a number of characteristic features or aspects that may include minimal embodied, minimal experiential, affective, intersubjective, psychological/cognitive, narrative, extended, and situated aspects. A pattern theory of self helps to clarify various interpretations of self as compatible or commensurable instead of thinking them in opposition, and it helps to show how various aspects of self may be related across certain dimensions. I also suggest that a pattern theory of self can help to adjudicate (or at least map the differences) between the idea that the self correlates to self-referential processing in the cortical midline structures of the brain and other narrower or wider conceptions of self.

The Embeddedness of Adolescent Friendship Nominations: The Formation of Social Capital in Emergent Network Structures.

Abstract: Although research on social embeddedness and social capital confirms the value of friendship networks, little has been written about how social relations form and are structured by social institutions. Using data from the Adolescent Health and Academic Achievement study and the National Longitudinal Study of Adolescent Health, the authors show that the odds of a new friendship nomination were 1.77 times greater within clusters of high school students taking courses together than between them. The estimated effect cannot be attributed to exposure to peers in similar grade levels, indirect friendship links, or pair-level course overlap, and the finding is robust to alternative model specifications. The authors also show how tendencies associated with status hierarchy inhering in triadic friendship nominations are neutralized within the clusters. These results have implications for the production and distribution of social capital within social systems such as schools, giving the clusters social salience as ...

Coseismic and postseismic slip associated with the 2010 Maule Earthquake, Chile: Characterizing the Arauco Peninsula barrier effect

Abstract: Observations of coseismic and postseismic deformation associated with the 2010 Mw = 8.8 Maule earthquake in south-central Chile provide constraints on the spatial heterogeneities of frictional properties on a major subduction megathrust and how they have influenced the seismic rupture and postseismic effects. We find that the bulk of coseismic slip occurs within a single elongated patch approximately 460 km long and 100 km wide between the depths of 15 and 40 km. We infer three major patches of afterslip: one extends northward along strike and downdip of the major coseismic patch between 40 and 60 km depth; the other two bound the northern and southern ends of the coseismic patch. The southern patch offshore of the Arauco Peninsula is the only place showing resolvable afterslip shallower than 20 km depth. Estimated slip potency associated with postseismic slip in the 1.3 years following the earthquake amounts to 20-30% of that generated coseismically. Our estimates of the megathrust frictional properties show that the Arauco Peninsula area has positive but relatively low (a−b)σn values (0.01 ~ 0.22 MPa), that would have allowed dynamic rupture propagation into this rate-strengthening area and afterslip. Given the only modestly rate-strengthening megathrust friction in this region, the barrier effect may be attributed to its relatively large size of the rate-strengthening patch. Coseismic and postseismic uplift of the Arauco Peninsula exceeds interseismic subsidence since the time of the last major earthquake in 1835, suggesting that coseismic and postseismic deformation has resulted in some permanent strain in the forearc.

The impact of chronic disease self-management programs: healthcare savings through a community-based intervention

Abstract: Background: Among the most studied evidence-based programs, the Chronic Disease Self-Management Program (CDSMP) has been shown to help participants improve their health behaviors, health outcomes, and reduce healthcare utilization. However, there is a lack of information on how CDSMP, when nationally disseminated, impacts healthcare utilization and averts healthcare costs. The purposes of this study were to: 1) document reductions in healthcare utilization among national CDSMP participants; 2) calculate potential cost savings associated with emergency room (ER) visits and hospitalizations; and 3) extrapolate the cost savings estimation to the American adults. Methods: The national study of CDSMP surveyed 1,170 community-dwelling CDSMP participants at baseline, 6 months, and 12 months from 22 organizations in 17 states. The procedure used to estimate potential cost savings included: 1) examining the pattern of healthcare utilization among CDSMP participants from self-reported healthcare utilization assessed at baseline, 6 months, and 12 months; 2) calculating age-adjusted average costs for persons using the 2010 Medical Expenditure Panel Survey; 3) calculating costs saved from reductions in healthcare utilization; 4) estimating per participant program costs; 5) computing potential cost savings by deducting program costs from estimated healthcare savings; and 6) extrapolating savings to national populations using Census data combined with national health statistics. Results: Findings from analyses showed significant reductions in ER visits (5%) at both the 6-month and 12-month assessments as well as hospitalizations (3%) at 6 months among national CDSMP participants. This equates to potential net savings of $364 per participant and a national savings of $3.3 billion if 5% of adults with one or more chronic conditions were reached. Conclusions: Findings emphasize the value of public health tertiary prevention interventions and the need for policies to support widespread adoption of CDSMP.

Exploring the Distinctive Nature of Work Commitments: Their Relationships with Personal Characteristics, Job Performance, and Propensity to Leave

Abstract: This study explores personal characteristics as antecedents to three types of work commitment: job, organizational, and career. Also, the relationships between these work commitments and key sales outcomes (performance and propensity to leave the organization) are assessed. We demonstrate the distinctive nature of these three work commitments while reducing the concept redundancy found between them and other forms of work commitment. The results indicate that each form of work commitment is uniquely related to a set of personal characteristics and sales outcomes. We also provide suggestions for future research and implications for sales managers.

National Study of Chronic Disease Self-Management Six-Month Outcome Findings

Abstract: Objective: To investigate how the Chronic Disease Self-Management Program (CDSMP) changes health outcomes, lifestyle behaviors, and health care service utilization over a 6 month period. Method: The participants were 1,170 adults enrolled in the National Study of CDSMP in 2010-2012 (M age = 65.4 years). Six-month assessments were available for 903 participants. Linear mixed models and generalized linear mixed models were used to assess the changes between baseline and 6-month assessment for primary and secondary outcomes among CDSMP participants. Results: Social/role activities limitations, depression, and communication with physicians improved significantly from baseline to 6-month follow-up. Study participants reported significant improvements in more physical activity and less emergency room (ER) visits and hospitalization during that period. Discussion: Nationally, CDSMP not only improves health outcomes and lifestyle behaviors but also decreases costly ER visits and hospitalization. Geriatricians and...

How Programmers Debug, Revisited: An Information Foraging Theory Perspective

Abstract: Many theories of human debugging rely on complex mental constructs that offer little practical advice to builders of software engineering tools. Although hypotheses are important in debugging, a theory of navigation adds more practical value to our understanding of how programmers debug. Therefore, in this paper, we reconsider how people go about debugging in large collections of source code using a modern programming environment. We present an information foraging theory of debugging that treats programmer navigation during debugging as being analogous to a predator following scent to find prey in the wild. The theory proposes that constructs of scent and topology provide enough information to describe and predict programmer navigation during debugging, without reference to mental states such as hypotheses. We investigate the scope of our theory through an empirical study of 10 professional programmers debugging a real-world open source program. We found that the programmers' verbalizations far more often concerned scent-following than hypotheses. To evaluate the predictiveness of our theory, we created an executable model that predicted programmer navigation behavior more accurately than comparable models that did not consider information scent. Finally, we discuss the implications of our results for enhancing software engineering tools.