Showing papers by "University of Memphis published in 2012"

The golden age: gold nanoparticles for biomedicine

Abstract: Gold nanoparticles have been used in biomedical applications since their first colloidal syntheses more than three centuries ago. However, over the past two decades, their beautiful colors and unique electronic properties have also attracted tremendous attention due to their historical applications in art and ancient medicine and current applications in enhanced optoelectronics and photovoltaics. In spite of their modest alchemical beginnings, gold nanoparticles exhibit physical properties that are truly different from both small molecules and bulk materials, as well as from other nanoscale particles. Their unique combination of properties is just beginning to be fully realized in range of medical diagnostic and therapeutic applications. This critical review will provide insights into the design, synthesis, functionalization, and applications of these artificial molecules in biomedicine and discuss their tailored interactions with biological systems to achieve improved patient health. Further, we provide a survey of the rapidly expanding body of literature on this topic and argue that gold nanotechnology-enabled biomedicine is not simply an act of ‘gilding the (nanomedicinal) lily’, but that a new ‘Golden Age’ of biomedical nanotechnology is truly upon us. Moving forward, the most challenging nanoscience ahead of us will be to find new chemical and physical methods of functionalizing gold nanoparticles with compounds that can promote efficient binding, clearance, and biocompatibility and to assess their safety to other biological systems and their long-term term effects on human health and reproduction (472 references).

The Golden Age: Gold Nanoparticles for Biomedicine

Abstract: Gold nanoparticles have been used in biomedical applications since their first colloidal syntheses more than three centuries ago. However, over the past two decades, their beautiful colors and unique electronic properties have also attracted tremendous attention due to their historical applications in art and ancient medicine and current applications in enhanced optoelectronics and photovoltaics. In spite of their modest alchemical beginnings, gold nanoparticles exhibit physical properties that are truly different from both small molecules and bulk materials, as well as from other nanoscale particles. Their unique combination of properties is just beginning to be fully realized in range of medical diagnostic and therapeutic applications. This critical review will provide insights into the design, synthesis, functionalization, and applications of these artificial molecules in biomedicine and discuss their tailored interactions with biological systems to achieve improved patient health. Further, we provide a survey of the rapidly expanding body of literature on this topic and argue that gold nanotechnology-enabled biomedicine is not simply an act of ‘gilding the (nanomedicinal) lily’, but that a new ‘Golden Age’ of biomedical nanotechnology is truly upon us. Moving forward, the most challenging nanoscience ahead of us will be to find new chemical and physical methods of functionalizing gold nanoparticles with compounds that can promote efficient binding, clearance, and biocompatibility and to assess their safety to other biological systems and their long-term term effects on human health and reproduction (472 references).

Consensus Paper: Pathological Role of the Cerebellum in Autism

Abstract: There has been significant advancement in various aspects of scientific knowledge concerning the role of cerebellum in the etiopathogenesis of autism. In the current consensus paper, we will observe the diversity of opinions regarding the involvement of this important site in the pathology of autism. Recent emergent findings in literature related to cerebellar involvement in autism are discussed, including: cerebellar pathology, cerebellar imaging and symptom expression in autism, cerebellar genetics, cerebellar immune function, oxidative stress and mitochondrial dysfunction, GABAergic and glutamatergic systems, cholinergic, dopaminergic, serotonergic, and oxytocin-related changes in autism, motor control and cognitive deficits, cerebellar coordination of movements and cognition, gene–environment interactions, therapeutics in autism, and relevant animal models of autism. Points of consensus include presence of abnormal cerebellar anatomy, abnormal neurotransmitter systems, oxidative stress, cerebellar motor and cognitive deficits, and neuroinflammation in subjects with autism. Undefined areas or areas requiring further investigation include lack of treatment options for core symptoms of autism, vermal hypoplasia, and other vermal abnormalities as a consistent feature of autism, mechanisms underlying cerebellar contributions to cognition, and unknown mechanisms underlying neuroinflammation.

Adaptive forwarding in named data networking

Abstract: In Named Data Networking (NDN) architecture, packets carry data names rather than source or destination addresses. This change of paradigm leads to a new data plane: data consumers send out Interest packets, routers forward them and maintain the state of pending Interests, which is used to guide Data packets back to the consumers. NDN routers' forwarding process is able to detect network problems by observing the two-way traffic of Interest and Data packets, and explore multiple alternative paths without loops. This is in sharp contrast to today's IP forwarding process which follows a single path chosen by the routing process, with no adaptability of its own. In this paper we outline the design of NDN's adaptive forwarding, articulate its potential benefits, and identify open research issues.

Disposal of Hydrofracking Waste Fluid by Injection into Subsurface Aquifers Triggers Earthquake Swarm in Central Arkansas with Potential for Damaging Earthquake

Abstract: Only a handful of the thousands of waste disposal wells across the United States have been linked to induced or triggered earthquakes. Still, two well-documented cases—Rocky Mountain Arsenal, Colorado, in the 1960s (Healy et al. 1968) and Paradox Valley, Colorado, in the 1990s (Ake et al. 2005)— demonstrate that fluid injection into the subsurface can trigger earthquakes. The largest event at Rocky Mountain Arsenal was M 5.2, and the largest event at Paradox Valley was M 4.3. The U.S. Environmental Protection Agency provides Underground Injection Control (UIC) regulations administered by the states to protect underground sources of drinking water. However, the UIC does not limit the proximity of waste disposal wells to active seismic zones or to critical facilities ( e.g. , hospitals, schools, or nuclear power plants) based on the potential to induce or trigger earthquakes. Over the last several years, hydraulic fracturing (hydrofracking), a technique used to enhance natural gas recovery, has become widely used in north-central Arkansas (Figure 1). Wastewater, a byproduct of the hydrofracking process, is being injected under pressure into subsurface rocks at eight waste disposal wells (Table 1) in the study area. Since the first waste disposal well became operational in April 2009, the study area has experienced an increase in the rate of magnitude ≥ 2.5 earthquakes, with one in 2007, two in 2008, 10 in 2009, 54 in 2010, and 157 in 2011. The study area has a long history of seismic activity including earthquake swarms in the early 1980s (Chiu et al. 1984) and 2001 (Rabak et al. 2010), so the current earthquake-rate increase may simply reflect another peak in a natural cycle. However, 98% of the recent earthquakes occurred within 6 km of one of three waste disposal wells after the start of injection at those wells. This close spatial and …

Size-dependent cell uptake of protein-coated graphene oxide nanosheets

Abstract: As an emerging applied material, graphene has shown tremendous application potential in many fields, including biomedicine. However, the biological behavior of these nanosheets, especially their interactions with cells, is not well understood. Here, we report our findings about the cell surface adhesion, subcellular locations, and size-dependent uptake mechanisms of protein-coated graphene oxide nanosheets (PCGO). Small nanosheets enter cells mainly through clathrin-mediated endocytosis, and the increase of graphene size enhances phagocytotic uptake of the nanosheets. These findings will facilitate biomedical and toxicologic studies of graphenes and provide fundamental understanding of interactions at the interface of two-dimensional nanostructures and biological systems.

Gaze tutor: A gaze-reactive intelligent tutoring system

Abstract: We developed an intelligent tutoring system (ITS) that aims to promote engagement and learning by dynamically detecting and responding to students' boredom and disengagement. The tutor uses a commercial eye tracker to monitor a student's gaze patterns and identify when the student is bored, disengaged, or is zoning out. The tutor then attempts to reengage the student with dialog moves that direct the student to reorient his or her attentional patterns towards the animated pedagogical agent embodying the tutor. We evaluated the efficacy of the gaze-reactive tutor in promoting learning, motivation, and engagement in a controlled experiment where 48 students were tutored on four biology topics with both gaze-reactive and non-gaze-reactive (control condition) versions of the tutor. The results indicated that: (a) gaze-sensitive dialogs were successful in dynamically reorienting students' attentional patterns to the important areas of the interface, (b) gaze-reactivity was effective in promoting learning gains for questions that required deep reasoning, (c) gaze-reactivity had minimal impact on students' state motivation and on self-reported engagement, and (d) individual differences in scholastic aptitude moderated the impact of gaze-reactivity on overall learning gains. We discuss the implications of our findings, limitations, future work, and consider the possibility of using gaze-reactive ITSs in classrooms.

Comprehending and Learning From Internet Sources: Processing Patterns of Better and Poorer Learners

Abstract: Readers increasingly attempt to understand and learn from information sources they find on the Internet. Doing so highlights the crucial role that evaluative processes play in selecting and making sense of the information. In a prior study, Wiley et al. (2009, Experiment 1) asked undergraduates to perform a web-based inquiry task about volcanoes using multiple Internet sources. A major finding established a clear link between learning outcomes, source evaluations, and reading behaviors. The present study used think-aloud protocol methodology to better understand the processing that learners engaged in during this task: 10 better learners were contrasted with 11 poorer learners. Results indicate that better learners engaged in more sense-making, self-explanation, and comprehension-monitoring processes on reliable sites as compared with unreliable sites, and did so by a larger margin than did poorer learners. Better learners also engaged in more goal-directed navigation than poorer learners. Case studies of two better and two poorer learners further illustrate how evaluation processes contributed to navigation decisions. Findings suggest that multiple-source comprehension is a dynamic process that involves interplay among sense-making, monitoring, and evaluation processes, all of which promote strategic reading. 阅读者日益想要弄明白及学习他们从互联网上各种来源所找到的信息资料。他们这样做突显出在选择和弄明白这些信息时评价过程所起的重要作用。威立等人在以前一项研究(2009,实验1)中,参与研究的大学生要利用互联网多种资源来完成一项关于火山的網路探究式学习任务。该研究的一个主要结果是建立了学习成果、信息来源评价与阅读行为之间的明确联系。本研究则使用有声思维研究方法,以深入考查学习者在参与同一个学习任务时他们处理信息的过程,并以10名表现较好的与11名表现较差的学习者作比对。结果显示,对于可靠网站上的资料,表现较好的学习者较多致力于弄明白自我解释的过程和理解监控的过程,而对于不可靠网站上的资料,这种行为则较少;他们这种行为亦远多于表现较差的学习者。此外,表现较好的学习者比表现较差的学习者较多致力于有目标的网上浏览。两个表现较好及两个表现较差的学习者的案例研究,进一步说明评价过程如何有助于在网上浏览时所作的决定。本研究结果显示,理解多种来源的信息是一个动态的过程,其中涉及弄明白、监控和评价过程之间的相互作用,而这些过程均能促进策略性阅读。 Es cada vez mas comun que lectores intenten entender y aprender de fuentes de informacion del Internet. Esto demuestra el rol crucial que los procesos de evaluacion tienen en seleccionar y sacar sentido de la informacion recibida. En un estudio anterior, Wiley et al. (2009, Experiment 1) les pidieron a subgraduados que hicieran una busqueda en la red sobre volcanes usando multiples fuentes del Internet. Un resultado clave establecio una conexion clara entre los resultados del aprendizaje, la evaluacion de las fuentes, y la manera de leer. El presente estudio uso la metodologia del protocolo de pensar en voz alta para mejor entender los procesos usados por los aprendices al cumplir dicha tarea: se compararon 10 aprendices mejores con 11 aprendices pobres. Los resultados senalan que los mejores aprendices buscaban sus propias explicaciones que hicieran sentido y procesos de monitoreo de comprension en sitios confiables comparados con los sitios que no eran confiables, y lo hacian con un margen mayor que los aprendices pobres. Un estudio de casos de dos mejores y dos pobres aprendices ilustran aun mas como los procesos de evaluacion contribuian al proceso de navegacion. Los resultados sugieren que la comprension de multiples fuentes es un proceso dinamico que requiere interaccion entre los procesos de hacer sentido, monitoreo, y evaluacion, todos de los cuales promulgan la lectura estrategica. يحاول القراء بشكل متزايد الفهم والتعلم من مصادر المعلومات التي يجدونها على شبكة الإنترنيت؛ وبذلك فهذا يسلط الضوء على الدور الحاسم الذي تلعبه عمليات التقييم في اختيار وإعطاء معنى للمعلومات. وفي دراسة سابقة طلب “وايلي” وآخرون (التجربة١،٢٠٠٩) من الطلبة الجامعيين إجراء بحث على شبكة الإنترنيت حول البراكين مستخدمين مصادر إنترنيت متعددة.تم التوصل إلى نتيجة رئيسية تقوم على أن هناك صلة واضحة بين التعلم وتقييمات المصدر وسلوكيات القراءة. استخدمت الدراسة الحالية منهجية بروتوكول التفكيير بصوت عال لفهم بشكل أفضل العمليات التي استخدمها المتعلمون أثناء هذه المهمة: تمت مقارنة ١٠من أفضل المتعلمين ب١١من أضعف المتعلمين. تشير النتائج إلى أن أفضل المتعلمين استخدموا عمليات أكثر في إعطاء معنى للتفسير الذاتي ومراقبة الفهم على مواقع موثوق بها بالمقارنة مع مواقع غير موثوق بها وفعلوا ذلك أكثر من أضعف المتعلمين. كما أن أفضل المتعلمين قد قاموا بالبحث على أهدافهم عبر الإنترنيت بصورة مباشرة. وتوضح كذلك دراسة الحالة لأفضل متعلمين وأضعف متعلمين كيف ساهمت عمليات التقييم في قرارات البحث عبر الإنترنيت. تشير النتائج إلى أن فهم المصادر المتعددة عملية فعالة تشمل التفاعل المتبادل بين إعطاء المعنى والمراقبة وعملية التقييم، وكل منها تنمي القراءة الاستراتيجية. Читaющиe люди вce чaщe oбpaщaютcя к интepнeтy кaк к иcтoчникy инфopмaции. Oднaкo, для eeгpaмoтнoгo oтбopa ивocпpиятиякpaйнeвaжнo yмeть oцeнить эти иcтoчники. B paнee пpoвeдeнныx иccлeдoвaнияx (Wiley и дp., 2009, Экcпepимeнт 1) yчeныe пpeдлoжили cтyдeнтaм млaдшиx кypcoв пoиcкaть мaтepиaл o вyлкaнax пo paзличныминтepнeт-caйтaм. B итoгe выявилacь пpямaя cвязь мeждy peзyльтaтaми yчeбнoй дeятeльнocти, yмeниeм oцeнить иcтoчники и caмим пoвeдeниeм cтyдeнтoв-читaтeлeй. B нacтoящeмиccлeдoвaнии, чтoбы лyчшe пoнять, кaк пpoиcxoдит пpoцecc oцeнивaния, иcпoльзoвaлcя мeтoд “paзмышлeниe вcлyx”, и cpaвнивaлиcь paзмышлeния дecяти лyчшиx и дecяти нaибoлee cлaбыx yчaщиxcя. Peзyльтaты пoкaзывaют, чтo cильныe yчaщиecя знaчитeльнo чaщe paбoтaют c нaдeжными caйтaми, бoльшe зaнимaютcя aнaлизoм инфopмaции и кoнтpoлиpyют coбcтвeннoe ocмыcлeниe пpoчитaннoгo. Кpoмe тoгo, caм пpoцecc иx ceтeвoгo пoиcкa бoлee цeлeнaпpaвлeн, чeм дeятeльнocть cлaбыx yчaщиxcя. B кaчecтвe иллюcтpaции oпиcaн пpoцecc oцeнивaния иcтoчникoв и cooтвeтcтвyющaя eмy тpaeктopия пoиcкa для двyx cильныx и двyx cлaбыx yчaщиxcя. Aвтopы пoлaгaют, чтo вocпpиятиe инфopмaции из мнoжecтвa иcтoчникoв – динaмичный пpoцecc, кoтopый coчeтaeт в ceбe вoccoздaниe нoвыx для читaтeля cмыcлoв, a тaкжe мoнитopинг и oцeнивaниe пpoцeccoв пoзнaния, чтo в coвoкyпнocти paзвивaeт нaвыки cтpaтeгичecкoгo чтeния. Les lecteurs essaient de plus en plus de comprendre et d'apprendre au moyen de sources d'information qu'ils trouvent sur Internet. Cette pratique souligne le role crucial que jouent les processus d’evaluation lors de la selection de l'information et du sens qu'on lui donne. Dans une etude precedente, Wiley et al. (2009, premiere experience) ont demande a des etudiants de premier cycle d'effectuer sur la Toile une recherche sur les volcans en utilisant plusieurs sources d'Internet. Des liens sont apparus clairement entre les resultats obtenus, les evaluations des sources et les comportements de lecture. L’etude presentee ici a utilise la methodologie du protocole consistant a penser a haute voix pour mieux comprendre la facon de proceder des lecteurs lors de cette tâche, ceci avec 10 eleves de bon niveau contrastes a 11 eleves de niveau faible. Les resultats montrent que les meilleurs eleves s'engagent dans des processus d'auto-explication de recherche du sens et de pilotage de la comprehension sur des sites plus fiables que d'autres, et qu'ils procedent ainsi plus largement que les moins bons eleves. Les meilleurs eleves sont aussi plus engages dans une navigation avec but que les moins bons eleves. L’etude de cas de deux bons eleves et de deux faibles permettant de mieux illustrer encore comment les processus d’evaluation contribuent aux decisions de navigation. Les resultats suggerent que la comprehension de sources multiples est un processus dynamique qui implique des interactions entre l'attribution de sens, le pilotage, et les processus d’evaluation, tous ces elements contribuant a une lecture strategique.

Is Talk 'Cheap'? An Initial Investigation of the Equivalence of Alcohol Purchase Task Performance for Hypothetical and Actual Rewards

Abstract: Background: Behavioral economic alcohol purchase tasks (APTs) are self-report measures of alcohol demand that assess estimated consumption at escalating levels of price. However, the relationship between estimated performance for hypothetical outcomes and choices for actual outcomes has not been determined. The present study examined both the correspondence between choices for hypothetical and actual outcomes, and the correspondence between estimated alcohol consumption and actual drinking behavior. A collateral goal of the study was to examine the effects of alcohol cues on APT performance. Methods: Forty-one heavy-drinking adults (56% men) participated in a human laboratory protocol comprising APTs for hypothetical and actual alcohol and money, an alcohol cue reactivity paradigm, an alcohol self-administration period, and a recovery period. Results: Pearson correlations revealed very high correspondence between APT performance for hypothetical and actual alcohol (ps Language: en

Composition of the solar corona, solar wind, and solar energetic particles

Abstract: Along with temperature and density, the elemental abundance is a basic parameter required by astronomers to understand and model any physical system. The abundances of the solar corona are known to differ from those of the solar photosphere via a mechanism related to the first ionization potential of the element, but the normalization of these values with respect to hydrogen is challenging. Here, we show that the values used by solar physicists for over a decade and currently referred to as the coronal abundances do not agree with the data themselves. As a result, recent analysis and interpretation of solar data involving coronal abundances may need to be revised. We use observations from coronal spectroscopy, the solar wind, and solar energetic particles as well as the latest abundances of the solar photosphere to establish a new set of abundances that reflect our current understanding of the coronal plasma.

Hormone therapy and Alzheimer disease dementia: New findings from the Cache County Study

Abstract: Objectives: Observational studies suggest reduced risk of Alzheimer disease (AD) in users of hormone therapy (HT), but trials show higher risk. We examined whether the association of HT with AD varies with timing or type of HT use. Methods: Between 1995 and 2006, the population-based Cache County Study followed 1,768 women who had provided a detailed history on age at menopause and use of HT. During this interval, 176 women developed incident AD. Cox proportional hazard models evaluated the association of HT use with AD, overall and in relation to timing, duration of use, and type (opposed vs unopposed) of HT. Results: Women who used any type of HT within 5 years of menopause had 30% less risk of AD (95% confidence interval 0.49–0.99), especially if use was for 10 or more years. By contrast, AD risk was not reduced among those who had initiated HT 5 or more years after menopause. Instead, rates were increased among those who began “opposed” estrogen-progestin compounds within the 3 years preceding the Cache County Study baseline (adjusted hazard ratio 1.93; 95% confidence interval 0.94–3.96). This last hazard ratio was similar to the ratio of 2.05 reported in randomized trial participants assigned to opposed HT. Conclusions: Association of HT use and risk of AD may depend on timing of use. Although possibly beneficial if taken during a critical window near menopause, HT (especially opposed compounds) initiated in later life may be associated with increased risk. The relation of AD risk to timing and type of HT deserves further study.

Predicting Second Language Writing Proficiency: The Roles of Cohesion and Linguistic Sophistication

Abstract: This study addresses research gaps in predicting second language (L2) writing proficiency using linguistic features. Key to this analysis is the inclusion of linguistic measures at the surface, textbase and situation model level that assess text cohesion and linguistic sophistication. The results of this study demonstrate that five variables (lexical diversity, word frequency, word meaningfulness, aspect repetition and word familiarity) can be used to significantly predict L2 writing proficiency. The results demonstrate that L2 writers categorised as highly proficient do not produce essays that are more cohesive, but instead produce texts that are more linguistically sophisticated. These findings have important implications for L2 writing development and L2 writing pedagogy.

A Randomized Controlled Trial of a Behavioral Economic Supplement to Brief Motivational Interventions for College Drinking

Abstract: Objective: Behavioral economic theory suggests that a reduction in substance use is most likely when there is an increase in rewarding substance-free activities. The goal of this randomized controlled clinical trial was to evaluate the incremental efficacy of a novel behavioral economic supplement (Substance-Free Activity Session [SFAS]) to a standard alcohol brief motivational interviewing (BMI) session for heavy-drinking college students. Method: Participants were 82 first-year college students (50% female; 81.7% White/European American; M age 18.5 years, SD 0.71) who reported 2 or more past-month heavy drinking episodes. After completing a baseline assessment and an individual alcohol-focused BMI, participants were randomized to either the SFAS or to a Relaxation Training (RT) control session. The SFAS was delivered in an MI style and attempted to increase the salience of delayed academic and career rewards and the patterns of behavior leading to those rewards. Results: The combination of an alcohol BMI plus the SFAS was associated with significantly greater reductions in alcohol problems compared with an alcohol BMI plus RT at the 1-month and 6-month follow-up assessments (p .015, p .07), an effect that was partially mediated by increases in protective behavioral strategies. BMI SFAS was also associated with greater reductions in heavy drinking among participants who at baseline reported low levels of substance-free reinforcement or symptoms of depression. Conclusion: These results are consistent with behavioral economic theory and suggest that a single session focused on increasing engagement in alternatives to drinking can enhance the effects of brief alcohol interventions.

Work engagement in nursing: a concept analysis

Abstract: antoinette bargagliotti l. (2012) Work engagement in nursing: a concept analysis. Journal of Advanced Nursing68(6), 1414–1428. Abstract Aim. This article is a report of an analysis of the concept of work engagement. Background. Work engagement is the central issue for 21st century professionals and specifically for registered nurses. Conceptual clarity about work engagement gives empirical direction for future research and a theoretical underpinning for the myriad studies about nurses and their work environment. Method. Walker and Avant’s method of concept analysis was used. Nursing, business, psychology and health sciences databases were searched using Science Direct, CINAHL, OVID, Academic One File, ABI INFORM and PsycINFO for publications that were: written in English, published between 1990 and 2010, and described or studied work engagement in any setting with any population. Results. Work engagement is a positive, fulfilling state of mind about work that is characterized by vigour, dedication and absorption. Trust (organizationally, managerially and collegially) and autonomy are the antecedents of work engagement. The outcomes of nurses’ work engagement are higher levels of personal initiative that are contagious, decreased hospital mortality rates and significantly higher financial profitability of organizations. Conclusion. When work engagement is conceptually removed from a transactional job demands-resources model, the relational antecedents of trust and autonomy have greater explanatory power for work engagement in nurses. Untangling the antecedents, attributes and outcomes of work engagement is important to future research efforts.

Soil Oxidation-Reduction in Wetlands and Its Impact on Plant Functioning

Abstract: Soil flooding in wetlands is accompanied by changes in soil physical and chemical characteristics. These changes include the lowering of soil redox potential (Eh) leading to increasing demand for oxygen within the soil profile as well as production of soil phytotoxins that are by-products of soil reduction and thus, imposing potentially severe stress on plant roots. Various methods are utilized for quantifying plant responses to reducing soil conditions that include measurement of radial oxygen transport, plant enzymatic responses, and assessment of anatomical/morphological changes. However, the chemical properties and reducing nature of soil environment in which plant roots are grown, including oxygen demand, and other associated processes that occur in wetland soils, pose a challenge to evaluation and comparison of plant responses that are reported in the literature. This review emphasizes soil-plant interactions in wetlands, drawing attention to the importance of quantifying the intensity and capacity of soil reduction for proper evaluation of wetland plant responses, particularly at the process and whole-plant levels. Furthermore, while root oxygen-deficiency may partially account for plant stress responses, the importance of soil phytotoxins, produced as by-products of low soil Eh conditions, is discussed and the need for development of methods to allow differentiation of plant responses to reduced or anaerobic soil conditions vs. soil phytotoxins is emphasized.

Advancing the Science of mHealth

Abstract: Mobile health (mHealth) technologies have the potential to greatly impact health research, health care, and health outcomes, but the exponential growth of the technology has outpaced the science. This article outlines two initiatives designed to enhance the science of mHealth. The mHealth Evidence Workshop used an expert panel to identify optimal methodological approaches for mHealth research. The NIH mHealth Training Institutes address the silos among the many academic and technology areas in mHealth research and is an effort to build the interdisciplinary research capacity of the field. Both address the growing need for high quality mobile health research both in the United States and internationally. mHealth requires a solid, interdisciplinary scientific approach that pairs the rapid change associated with technological progress with a rigorous evaluation approach. The mHealth Evidence Workshop and the NIH mHealth Training Institutes were both designed to address and further develop this scientific app...

The sharp threshold for bootstrap percolation in all dimensions

Abstract: In r-neighbour bootstrap percolation on a graph G, a (typically random) set A of initially 'infected' vertices spreads by infecting (at each time step) vertices with at least r already-infected neighbours. This process may be viewed as a monotone version of the Glauber dynamics of the Ising model, and has been extensively studied on the d-dimensional grid $[n]^d$. The elements of the set A are usually chosen independently, with some density p, and the main question is to determine $p_c([n]^d,r)$, the density at which percolation (infection of the entire vertex set) becomes likely. In this paper we prove, for every pair $d ge r ge 2$, that there is a constant L(d,r) such that $p_c([n]^d,r) = [(L(d,r) + o(1)) / log_(r-1) (n)]^{d-r+1}$ as $n o infty$, where $log_r$ denotes an r-times iterated logarithm. We thus prove the existence of a sharp threshold for percolation in any (fixed) number of dimensions. Moreover, we determine L(d,r) for every pair (d,r).

A Comparison of Greedy and Optimal Assessment of Natural Language Student Input Using Word-to-Word Similarity Metrics

Abstract: We present in this paper a novel, optimal semantic similarity approach based on word-to-word similarity metrics to solve the important task of assessing natural language student input in dialogue-based intelligent tutoring systems. The optimal matching is guaranteed using the sailor assignment problem, also known as the job assignment problem, a well-known combinatorial optimization problem. We compare the optimal matching method with a greedy method as well as with a baseline method on data sets from two intelligent tutoring systems, AutoTutor and iSTART.

Models of Massive Parallelism: Analysis of Cellular Automata and Neural Networks

Abstract: This textbook provides an introduction to the fundamental models of massively parallel computation, the most important technique for high-performance computing. It presents a coherent exposition of analytic methods and results for the exploration and understanding of cellular automata and discrete neural networks as computational and dynamical systems. The book will be useful also as a reference manual to the scattered literature in the field. Each chapter includes a separate bibliography, as well as pointers to historically relevant papers, and gives exercise problems for the reader.

EMNEs and Knowledge-seeking FDI

Abstract: Knowledge is the preeminent resource of firms that wish to become and/or remain globally competitive. This is especially true for emerging market multinationals, whose ability to overcome their inherent disadvantages as latecomers relies heavily on their ability to seek knowledge outside of their home borders through foreign direct investment. Our conceptual framework explores drivers of knowledge-seeking foreign direct investment, the types of functional knowledge sought, and the impact on location choice and entry mode decisions. It is argued that EMNE knowledge-seeking outward FDI is not based on the traditional asset-exploitation model of FDI, but rather tends to be focused on asset-augmentation through the exploitation of EMNE unique circumstances. Specifically, this work posits that an EMNE’s strategic orientation predicts its propensity to engage in knowledge-seeking FDI and that the type of knowledge sought predicts location choice and entry mode.

A New Open Door: The Smartphone's Impact on Work-to-Life Conflict, Stress, and Resistance

Abstract: Use of job-provided or personally owned smartphones at work and at home, henceforth office-home smartphone (OHS), has created a "new open door policy," portending many changes for employees and organizations. We examine the unique attributes of OHS use, such as flexibility, productivity, and work overload, along with the impact of these attributes on work-to-life conflict and other work-related outcomes. The findings of this study show that an increased work overload due to OHS use results in greater work-to-life conflict, which creates job stress and user resistance to OHS; however, productivity gained due to OHS use can reduce work overload. Our findings indicate that business organizations can minimize negative effects of OHS by promoting an organizational culture that supports segmentation of work and attempts to minimize work-to-life conflict and its consequences. Results also provide guidance to scholars seeking a comprehensive research model on the use of smartphones traversing work and home.

Can states buy peace? Social welfare spending and civil conflicts:

Abstract: This study examines whether the state’s ability to provide social welfare services has any major effect on the probability of civil conflict onset. We argue that welfare spending contributes to sus...

When the PCAOB talks, Who Listens? Evidence from Stakeholder Reaction to GAAP- Deficient PCAOB Inspection Reports of Small Auditors

Abstract: Section 104 of the Sarbanes-Oxley Act (SOX) created the Public Company Accounting Oversight Board (PCAOB). The PCAOB conducts inspections of registered public accounting firms that provide audits for publicly traded companies. The results of the inspection process are summarized in publicly available reports at the PCAOB website. Using these reports, we categorize the inspection reports into three levels of increasing severity: clean, GAAS-deficient, and GAAP-deficient. We examine the potential use of GAAP-deficient PCAOB inspection reports as perceived audit quality signals for the clients of GAAP-deficient auditors that are inspected on a triennial basis by the PCAOB. Our investigation is predicated on the notion that audit quality is generally not directly observable. Thus the clients of these auditors may seek to signal their desire for audit quality by dismissing their GAAP-deficient auditors. Our results suggest that the clients of GAAP-deficient, triennially inspected auditors are more likely to dismiss these auditors in favor of triennially inspected auditors that are not GAAP-deficient. In addition, we find that greater agency conflicts, the presence of an independent and expert audit committee, and outside blockholdings magnify this effect. Interestingly, we find no evidence that the clients use GAAP-deficient reports to procure a subsequent year audit fee discount or more favorable going-concern auditor reporting treatment. Our evidence indicates that PCAOB inspection reports created heterogeneity in auditor brand name among a group of non-Big N/non-national auditors that did not previously exist and universally treated by prior research as “other auditors.”