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Sample records for rethinking natural interactions

  1. Rethinking natural altruism: Simple reciprocal interactions trigger children’s benevolence

    PubMed Central

    Cortes Barragan, Rodolfo; Dweck, Carol S.

    2014-01-01

    A very simple reciprocal activity elicited high degrees of altruism in 1- and 2-y-old children, whereas friendly but nonreciprocal activity yielded little subsequent altruism. In a second study, reciprocity with one adult led 1- and 2-y-olds to provide help to a new person. These results question the current dominant claim that social experiences cannot account for early occurring altruistic behavior. A third study, with preschool-age children, showed that subtle reciprocal cues remain potent elicitors of altruism, whereas a fourth study with preschoolers showed that even a brief reciprocal experience fostered children’s expectation of altruism from others. Collectively, the studies suggest that simple reciprocal interactions are a potent trigger of altruism for young children, and that these interactions lead children to believe that their relationships are characterized by mutual care and commitment. PMID:25404334

  2. Emergent Interactions: Rethinking the Relationship between Teaching and Learning

    ERIC Educational Resources Information Center

    Case, Jennifer M.

    2015-01-01

    The relationship between teaching and learning is represented in contemporary higher education research which has looked at the correlations between students' approaches to learning and teachers' approaches to teaching. This article proposes a rethinking of this relationship, building on a critical realist perspective. Here, the teaching-learning…

  3. Rethinking the Natural Capital Metaphor: Implications for Education and Learning

    ERIC Educational Resources Information Center

    Gough, Stephen

    2005-01-01

    One way in which the concept of sustainable development has been understood is through the metaphor of natural capital. This sees that the natural world has performing functions similar to those of economic capital. This metaphor is usually developed by applying to Nature standard economic techniques for capital valuation. However, where valuation…

  4. Rethinking niche evolution: experiments with natural communities of Protozoa in pitcher plants.

    PubMed

    Miller, Thomas E; Moran, Emma R; terHorst, Casey P

    2014-08-01

    Classic niche theory predicts that competing species will evolve to use different resources and interact less, whereas recent niche-converge ideas predict that species evolve to use similar resources and interact more. Most data supporting niche evolution are based on observations of contemporary niche use, whereas experimental support is quite sparse. We followed the evolution of four species of Protozoa during succession in the water-filled leaves of the pitcher plant, Sarracenia purpurea, and found that evolution in multispecies systems follows a surprising pattern. Over several hundred generations, weak competitors evolved to be stronger, while strong competitors evolved to become weaker, which does not conform to expectations of either niche divergence or convergence. Evolution in this system appears to occur in response to characteristics of a suite of several competitors in the community, rather than pairwise interactions. Ecologists may need to rethink the roles of competition and evolution in structuring communities.

  5. Rethinking the process of detrainment: jets in obstructed natural flows

    NASA Astrophysics Data System (ADS)

    Mossa, Michele; de Serio, Francesca

    2016-12-01

    A thorough understanding of the mixing and diffusion of turbulent jets released in porous obstructions is still lacking in literature. This issue is undoubtedly of interest because it is not strictly limited to vegetated flows, but also includes outflows which come from different sources and which spread among oyster or wind farms, as well as aerial pesticide treatments sprayed onto orchards. The aim of the present research is to analyze this process from a theoretical point of view. Specifically, by examining the entrainment coefficient, it is deduced that the presence of a canopy prevents a momentum jet from having an entrainment process, but rather promotes its detrainment. In nature, detrainment is usually associated with buoyancy-driven flows, such as plumes or density currents flowing in a stratified environment. The present study proves that detrainment occurs also when a momentum-driven jet is issued in a not-stratified obstructed current, such as a vegetated flow.

  6. Rethinking the process of detrainment: jets in obstructed natural flows

    PubMed Central

    Mossa, Michele; De Serio, Francesca

    2016-01-01

    A thorough understanding of the mixing and diffusion of turbulent jets released in porous obstructions is still lacking in literature. This issue is undoubtedly of interest because it is not strictly limited to vegetated flows, but also includes outflows which come from different sources and which spread among oyster or wind farms, as well as aerial pesticide treatments sprayed onto orchards. The aim of the present research is to analyze this process from a theoretical point of view. Specifically, by examining the entrainment coefficient, it is deduced that the presence of a canopy prevents a momentum jet from having an entrainment process, but rather promotes its detrainment. In nature, detrainment is usually associated with buoyancy-driven flows, such as plumes or density currents flowing in a stratified environment. The present study proves that detrainment occurs also when a momentum-driven jet is issued in a not-stratified obstructed current, such as a vegetated flow. PMID:27974835

  7. Rethinking the logistic approach for population dynamics of mutualistic interactions.

    PubMed

    García-Algarra, Javier; Galeano, Javier; Pastor, Juan Manuel; Iriondo, José María; Ramasco, José J

    2014-12-21

    Mutualistic communities have an internal structure that makes them resilient to external perturbations. Late research has focused on their stability and the topology of the relations between the different organisms to explain the reasons of the system robustness. Much less attention has been invested in analyzing the systems dynamics. The main population models in use are modifications of the r-K formulation of logistic equation with additional terms to account for the benefits produced by the interspecific interactions. These models have shortcomings as the so-called r-K formulation diverges under some conditions. In this work, we introduce a model for population dynamics under mutualism that preserves the original logistic formulation. It is mathematically simpler than the widely used type II models, although it shows similar complexity in terms of fixed points and stability of the dynamics. We perform an analytical stability analysis and numerical simulations to study the model behavior in general interaction scenarios including tests of the resilience of its dynamics under external perturbations. Despite its simplicity, our results indicate that the model dynamics shows an important richness that can be used to gain further insights in the dynamics of mutualistic communities.

  8. Natural interaction for unmanned systems

    NASA Astrophysics Data System (ADS)

    Taylor, Glenn; Purman, Ben; Schermerhorn, Paul; Garcia-Sampedro, Guillermo; Lanting, Matt; Quist, Michael; Kawatsu, Chris

    2015-05-01

    Military unmanned systems today are typically controlled by two methods: tele-operation or menu-based, search-andclick interfaces. Both approaches require the operator's constant vigilance: tele-operation requires constant input to drive the vehicle inch by inch; a menu-based interface requires eyes on the screen in order to search through alternatives and select the right menu item. In both cases, operators spend most of their time and attention driving and minding the unmanned systems rather than on being a warfighter. With these approaches, the platform and interface become more of a burden than a benefit. The availability of inexpensive sensor systems in products such as Microsoft Kinect™ or Nintendo Wii™ has resulted in new ways of interacting with computing systems, but new sensors alone are not enough. Developing useful and usable human-system interfaces requires understanding users and interaction in context: not just what new sensors afford in terms of interaction, but how users want to interact with these systems, for what purpose, and how sensors might enable those interactions. Additionally, the system needs to reliably make sense of the user's inputs in context, translate that interpretation into commands for the unmanned system, and give feedback to the user. In this paper, we describe an example natural interface for unmanned systems, called the Smart Interaction Device (SID), which enables natural two-way interaction with unmanned systems including the use of speech, sketch, and gestures. We present a few example applications SID to different types of unmanned systems and different kinds of interactions.

  9. Rethinking the senses and their interactions: the case for sensory pluralism

    PubMed Central

    Fulkerson, Matthew

    2014-01-01

    I argue for sensory pluralism. This is the view that there are many forms of sensory interaction and unity, and no single category that classifies them all. In other words, sensory interactions do not form a single natural kind. This view suggests that how we classify sensory systems (and the experiences they generate) partly depends on our explanatory purposes. I begin with a detailed discussion of the issue as it arises for our understanding of thermal perception, followed by a general account and defense of sensory pluralism. PMID:25540630

  10. Rethinking the area of protection "natural resources" in life cycle assessment.

    PubMed

    Dewulf, Jo; Benini, Lorenzo; Mancini, Lucia; Sala, Serenella; Blengini, Gian Andrea; Ardente, Fulvio; Recchioni, Marco; Maes, Joachim; Pant, Rana; Pennington, David

    2015-05-05

    Life cycle impact assessment (LCIA) in classical life cycle assessment (LCA) aims at analyzing potential impacts of products and services typically on three so-called areas of protection (AoPs): Natural Environment, Human Health, and Natural Resources. This paper proposes an elaboration of the AoP Natural Resources. It starts with analyzing different perspectives on Natural Resources as they are somehow sandwiched in between the Natural Environment (their cradle) and the human-industrial environment (their application). Reflecting different viewpoints, five perspectives are developed with the suggestion to select three in function of classical LCA. They result in three safeguard subjects: the Asset of Natural Resources, their Provisioning Capacity, and their role in Global Functions. Whereas the Provisioning Capacity is fully in function of humans, the global functions go beyond provisioning as they include nonprovisioning functions for humans and regulating and maintenance services for the globe as a whole, following the ecosystem services framework. A fourth and fifth safeguard subject has been identified: recognizing the role Natural Resources for human welfare, either specifically as building block in supply chains of products and services as such, either with or without their functions beyond provisioning. But as these are far broader as they in principle should include characterization of mechanisms within the human industrial society, they are considered as subjects for an integrated sustainability assessment (LCSA: life cycle sustainability assessment), that is, incorporating social, economic and environmental issues.

  11. Rethinking Diversity.

    ERIC Educational Resources Information Center

    1996

    These three papers were presented at a symposium on rethinking diversity in human resource development (HRD) moderated by Neal Chalofsky at the 1996 conference of the Academy of Human Resource Development. "Diversity: A Double-Edged Sword" (Sally F. Angus) presents the notion of work force diversity through two differing perspectives in order to…

  12. Rousseau and the Fable: Rethinking the Fabulous Nature of Educational Philosophy

    ERIC Educational Resources Information Center

    Lewis, Tyson E.

    2012-01-01

    In this essay Tyson Lewis reevaluates Jean-Jacques Rousseau's assessment of the pedagogical value of fables in Emile's education using Giorgio Agamben's theory of poetic production and Thomas Keenan's theory of the inherent ambiguity of the fable. From this perspective, the "unreadable" nature of the fable that Rousseau exposed is not simply the…

  13. "Before Today, I Was Afraid of Trees": Rethinking Nature Deficit Disorder

    ERIC Educational Resources Information Center

    Larkin, Doug

    2011-01-01

    Science teachers in urban schools often serve students whose experiences with the natural environment are more obviously constrained by human factors than their suburban or rural counterparts. At the same time, parents and teachers are contending with an increase in sedentary indoor activities that have affected youth of every demographic. Coupled…

  14. Rethinking the Nature of Disaster: From Failed Instruments of Learning to a Post-Social Understanding

    ERIC Educational Resources Information Center

    Williams, Stewart

    2008-01-01

    Recent disasters have been of such scale and complexity that both the common assumptions made about learning from them, and the traditional approaches distinguishing natural from technological disasters (and now terrorism) are thus challenged. Beck's risk thesis likewise signals the need for a paradigmatic change. Despite sociological inflections…

  15. Holocene Changes in Land Cover and Greenhouse-gas Concentrations: Rethinking Natural vs Anthropogenic Causation

    NASA Astrophysics Data System (ADS)

    Roberts, C.

    2008-12-01

    The Holocene has witnessed a switch from a nature-dominated to a human-dominated Earth system. Although globally-significant human impacts (wildfire, megafaunal extinctions) occurred during the late Pleistocene, it was the advent of agriculture that led to the progressive transformation of land cover, and which distinguishes the Holocene from previous interglacial periods. A wide array of data provide clear evidence of local-to-regional human disturbance from ~5 ka BP, in some cases earlier. There is more uncertainty about when the anthropogenic "footprint" became detectable at a global scale, and there has consequently been debate about how much of the pre-industrial increase in atmospheric greenhouse gas concentrations is attributable to human causation, linked to processes such as deforestation (CO2) and wet rice cultivation (CH4). Although there has been recent progress in developing quantitative methods for translating pollen data into palaeo-land cover, such as the REVEALS model of Sugita (Holocene 2007) coupled to GIS, this has yet to be widely applied to existing data bases, and most pollen-based land-use reconstructions remain qualitative or semi-quantitative. Lake trophic status, sediment flux / soil erosion, and microcharcoal records of biomass burning provide alternative proxies that integrate regional-scale landscape disturbance. These proxy data along with documentary sources imply that globally-significant changes in land cover occurred prior to ~250 BP which must have altered atmospheric greenhouse gas concentrations by this time. The polarised debate for and against early anthropogenic impact on global carbon cycling mirrors our industrial-era division between nature and society, both conceptually (e.g. Cartesian dualism) and on the ground (e.g. demarcating land between monoculture agriculture and wilderness). However, for the period before ~1750 AD, this likely represents a false dichotomy, because pre-industrial societies more often formed part

  16. Troublesome toxins: Time to re-think plant-herbivore interactions in vertebrate ecology

    USGS Publications Warehouse

    Swihart, R.K.; DeAngelis, D.L.; Feng, Z.; Bryant, J.P.

    2009-01-01

    Earlier models of plant-herbivore interactions relied on forms of functional response that related rates of ingestion by herbivores to mechanical or physical attributes such as bite size and rate. These models fail to predict a growing number of findings that implicate chemical toxins as important determinants of plant-herbivore dynamics. Specifically, considerable evidence suggests that toxins set upper limits on food intake for many species of herbivorous vertebrates. Herbivores feeding on toxin-containing plants must avoid saturating their detoxification systems, which often occurs before ingestion rates are limited by mechanical handling of food items. In light of the importance of plant toxins, a new approach is needed to link herbivores to their food base. We discuss necessary features of such an approach, note recent advances in herbivore functional response models that incorporate effects of plant toxins, and mention predictions that are consistent with observations in natural systems. Future ecological studies will need to address explicitly the importance of plant toxins in shaping plant and herbivore communities.

  17. Rethinking Drinking: Alcohol and Your Health | NIH MedlinePlus the Magazine

    MedlinePlus

    ... this page please turn JavaScript on. Rethinking Drinking: Alcohol and Your Health Past Issues / Spring 2014 Table of Contents RETHINKING DRINKING Alcohol and Your Health Visit NIAAA's Fully Interactive Web ...

  18. Rethinking echolalia: repetition as interactional resource in the communication of a child with autism.

    PubMed

    Sterponi, Laura; Shankey, Jennifer

    2014-03-01

    Echolalia is a pervasive phenomenon in verbal children with autism, traditionally conceived of as an automatic behavior with no communicative function. However, recently it has been shown that echoes may serve interactional goals. This article, which presents a case study of a six-year-old child with autism, examines how social interaction organizes autism echolalia and how repetitive speech responds to discernible interactional trajectories. Using linguistic, discourse, and acoustic analyses, we demonstrate that the child is able to mobilize echolalia to mark different stances, through the segmental and suprasegmental modulation of echoes. We offer an interpretive framework that deepens our understanding of the complex interactions that children with autism can engage in by using echoes, and discuss the implications of this perspective for current views of atypical language development in autism.

  19. Rethinking ideology.

    PubMed

    Young, A

    1983-01-01

    Rethinking the relationship between medicine and ideology means investigating the origins of the efficacy of ideological knowledge. Only after this investigation is completed is it possible to advance claims about dominance and hegemony. In order to rethink ideology, it is useful to divide the field into three levels of analysis: the level of ideological knowledge, where manifold and contradictory facts and meanings are produced and come to occupy the consciousness of the individual; the level of ideological discourse, where ideological knowledge is organized into trajectories of dominant facts and meanings; and the level of ideological process, where discourses are given authority and, sometimes, incorporated into ideological hegemonies. However, such an investigation requires that we reject certain preconceptions about "rationality." In the sovereign sense in which empiricist writers use this term, it has the effect of hiding the origins of ideological knowledge by desocializing its mode of production. Correctly understood, rationality is only one element within a socially determined and embedded rationalization process through which dominant facts and meanings are produced. Only by distinguishing between rationality (an aspect of mind) and rationalization (a social process) is it possible to clarify the relationship between ideology, medicine, and science.

  20. Rethinking Echolalia: Repetition as Interactional Resource in the Communication of a Child with Autism

    ERIC Educational Resources Information Center

    Sterponi, Laura; Shankey, Jennifer

    2014-01-01

    Echolalia is a pervasive phenomenon in verbal children with autism, traditionally conceived of as an automatic behavior with no communicative function. However, recently it has been shown that echoes may serve interactional goals. This article, which presents a case study of a six-year-old child with autism, examines how social interaction…

  1. Rethinking Human-Centered Computing: Finding the Customer and Negotiated Interactions at the Airport

    NASA Technical Reports Server (NTRS)

    Wales, Roxana; O'Neill, John; Mirmalek, Zara

    2003-01-01

    The breakdown in the air transportation system over the past several years raises an interesting question for researchers: How can we help improve the reliability of airline operations? In offering some answers to this question, we make a statement about Huuman-Centered Computing (HCC). First we offer the definition that HCC is a multi-disciplinary research and design methodology focused on supporting humans as they use technology by including cognitive and social systems, computational tools and the physical environment in the analysis of organizational systems. We suggest that a key element in understanding organizational systems is that there are external cognitive and social systems (customers) as well as internal cognitive and social systems (employees) and that they interact dynamically to impact the organization and its work. The design of human-centered intelligent systems must take this outside-inside dynamic into account. In the past, the design of intelligent systems has focused on supporting the work and improvisation requirements of employees but has often assumed that customer requirements are implicitly satisfied by employee requirements. Taking a customer-centric perspective provides a different lens for understanding this outside-inside dynamic, the work of the organization and the requirements of both customers and employees In this article we will: 1) Demonstrate how the use of ethnographic methods revealed the important outside-inside dynamic in an airline, specifically the consequential relationship between external customer requirements and perspectives and internal organizational processes and perspectives as they came together in a changing environment; 2) Describe how taking a customer centric perspective identifies places where the impact of the outside-inside dynamic is most critical and requires technology that can be adaptive; 3) Define and discuss the place of negotiated interactions in airline operations, identifying how these

  2. Rethinking schizophrenia.

    PubMed

    Insel, Thomas R

    2010-11-11

    How will we view schizophrenia in 2030? Schizophrenia today is a chronic, frequently disabling mental disorder that affects about one per cent of the world's population. After a century of studying schizophrenia, the cause of the disorder remains unknown. Treatments, especially pharmacological treatments, have been in wide use for nearly half a century, yet there is little evidence that these treatments have substantially improved outcomes for most people with schizophrenia. These current unsatisfactory outcomes may change as we approach schizophrenia as a neurodevelopmental disorder with psychosis as a late, potentially preventable stage of the illness. This 'rethinking' of schizophrenia as a neurodevelopmental disorder, which is profoundly different from the way we have seen this illness for the past century, yields new hope for prevention and cure over the next two decades.

  3. Transnational indigenous exchange: rethinking global interactions of indigenous peoples at the 1904 St. Louis Exposition.

    PubMed

    Medak-Saltzman, Danika

    2010-01-01

    When the St. Louis Exposition opened in 1904 it became host to the largest gathering of the world's Indigenous peoples to that date. However, questions about how Native peoples understood these transnational Indigenous interactions have remained largely out of the realm of academic inquiry-a fact often attributed to the "absence" of primary sources. This article counters such assertions by providing a rereading that interrogates colonial assumptions embedded in both archival materials and contemporary scholarly interpretations. By analyzing a candid photograph of two Native women-one Tzoneca, the other Ainu-taken at the fair by Jessie Tarbox Beals and utilizing Frederick Starr's journal, this article ultimately questions whether the Exposition's celebration of empire may have inadvertently served anti-colonial purposes. Namely, by presenting Indigenous participants with opportunities to forge relationships across the globe, a fact that may have served to inform the late 20th century emergence of a global Indigenous consciousness.

  4. Rethinking expertise: A multifactorial gene-environment interaction model of expert performance.

    PubMed

    Ullén, Fredrik; Hambrick, David Zachary; Mosing, Miriam Anna

    2016-04-01

    Scientific interest in expertise-superior performance within a specific domain-has a long history in psychology. Although there is a broad consensus that a long period of practice is essential for expertise, a long-standing controversy in the field concerns the importance of other variables such as cognitive abilities and genetic factors. According to the influential deliberate practice theory, expert performance is essentially limited by a single variable: the amount of deliberate practice an individual has accumulated. Here, we provide a review of the literature on deliberate practice, expert performance, and its neural correlates. A particular emphasis is on recent studies indicating that expertise is related to numerous traits other than practice as well as genetic factors. We argue that deliberate practice theory is unable to account for major recent findings relating to expertise and expert performance, and propose an alternative multifactorial gene-environment interaction model of expertise, which provides an adequate explanation for the available empirical data and may serve as a useful framework for future empirical and theoretical work on expert performance.

  5. Learning procedures from interactive natural language instructions

    NASA Technical Reports Server (NTRS)

    Huffman, Scott B.; Laird, John E.

    1994-01-01

    Despite its ubiquity in human learning, very little work has been done in artificial intelligence on agents that learn from interactive natural language instructions. In this paper, the problem of learning procedures from interactive, situated instruction is examined in which the student is attempting to perform tasks within the instructional domain, and asks for instruction when it is needed. Presented is Instructo-Soar, a system that behaves and learns in response to interactive natural language instructions. Instructo-Soar learns completely new procedures from sequences of instruction, and also learns how to extend its knowledge of previously known procedures to new situations. These learning tasks require both inductive and analytic learning. Instructo-Soar exhibits a multiple execution learning process in which initial learning has a rote, episodic flavor, and later executions allow the initially learned knowledge to be generalized properly.

  6. Rethinking map legends with visualization.

    PubMed

    Dykes, Jason; Wood, Jo; Slingsby, Aidan

    2010-01-01

    This design paper presents new guidance for creating map legends in a dynamic environment. Our contribution is a set of guidelines for legend design in a visualization context and a series of illustrative themes through which they may be expressed. These are demonstrated in an applications context through interactive software prototypes. The guidelines are derived from cartographic literature and in liaison with EDINA who provide digital mapping services for UK tertiary education. They enhance approaches to legend design that have evolved for static media with visualization by considering: selection, layout, symbols, position, dynamism and design and process. Broad visualization legend themes include: The Ground Truth Legend, The Legend as Statistical Graphic and The Map is the Legend. Together, these concepts enable us to augment legends with dynamic properties that address specific needs, rethink their nature and role and contribute to a wider re-evaluation of maps as artifacts of usage rather than statements of fact. EDINA has acquired funding to enhance their clients with visualization legends that use these concepts as a consequence of this work. The guidance applies to the design of a wide range of legends and keys used in cartography and information visualization.

  7. Bacteria-phage interactions in natural environments.

    PubMed

    Díaz-Muñoz, Samuel L; Koskella, Britt

    2014-01-01

    Phages are considered the most abundant and diverse biological entities on Earth and are notable not only for their sheer abundance, but also for their influence on bacterial hosts. In nature, bacteria-phage relationships are complex and have far-reaching consequences beyond particular pairwise interactions, influencing everything from bacterial virulence to eukaryotic fitness to the carbon cycle. In this review, we examine bacteria and phage distributions in nature first by highlighting biogeographic patterns and nonhost environmental influences on phage distribution, then by considering the ways in which phages and bacteria interact, emphasizing phage life cycles, bacterial responses to phage infection, and the complex patterns of phage host specificity. Finally, we discuss phage impacts on bacterial abundance, genetics, and physiology, and further aim to clarify distinctions between current theoretical models and point out areas in need of future research.

  8. Rethinking language in autism.

    PubMed

    Sterponi, Laura; de Kirby, Kenton; Shankey, Jennifer

    2015-07-01

    In this article, we invite a rethinking of traditional perspectives of language in autism. We advocate a theoretical reappraisal that offers a corrective to the dominant and largely tacitly held view that language, in its essence, is a referential system and a reflection of the individual's cognition. Drawing on scholarship in Conversation Analysis and linguistic anthropology, we present a multidimensional view of language, showing how it also functions as interactional accomplishment, social action, and mode of experience. From such a multidimensional perspective, we revisit data presented by other researchers that include instances of prototypical features of autistic speech, giving them a somewhat different-at times complementary, at times alternative-interpretation. In doing so, we demonstrate that there is much at stake in the view of language that we as researchers bring to our analysis of autistic speech. Ultimately, we argue that adopting a multidimensional view of language has wide ranging implications, deepening our understanding of autism's core features and developmental trajectory.

  9. Resilience to Interacting multi-natural hazards

    NASA Astrophysics Data System (ADS)

    Zhuo, Lu; Han, Dawei

    2016-04-01

    Conventional analyses of hazard assessment tend to focus on individual hazards in isolation. However, many parts of the world are usually affected by multiple natural hazards with the potential for interacting relationships. The understanding of such interactions, their impacts and the related uncertainties, are an important and topical area of research. Interacting multi-hazards may appear in different forms, including 1) CASCADING HAZARDS (a primary hazard triggering one or more secondary hazards such as an earthquake triggering landslides which may block river channels with dammed lakes and ensued floods), 2) CONCURRING HAZARDS (two or more primary hazards coinciding to trigger or exacerbate secondary hazards such as an earthquake and a rainfall event simultaneously creating landslides), and 3) ALTERING HAZARDS (a primary hazard increasing the probability of a secondary hazard occurring such as major earthquakes disturbing soil/rock materials by violent ground shaking which alter the regional patterns of landslides and debris flows in the subsequent years to come). All three types of interacting multi-hazards may occur in natural hazard prone regions, so it is important that research on hazard resilience should cover all of them. In the past decades, great progresses have been made in tackling disaster risk around the world. However, there are still many challenging issues to be solved, and the disasters over recent years have clearly demonstrated the inadequate resilience in our highly interconnected and interdependent systems. We have identified the following weaknesses and knowledge gaps in the current disaster risk management: 1) although our understanding in individual hazards has been greatly improved, there is a lack of sound knowledge about mechanisms and processes of interacting multi-hazards. Therefore, the resultant multi-hazard risk is often significantly underestimated with severe consequences. It is also poorly understood about the spatial and

  10. Interactive natural image segmentation via spline regression.

    PubMed

    Xiang, Shiming; Nie, Feiping; Zhang, Chunxia; Zhang, Changshui

    2009-07-01

    This paper presents an interactive algorithm for segmentation of natural images. The task is formulated as a problem of spline regression, in which the spline is derived in Sobolev space and has a form of a combination of linear and Green's functions. Besides its nonlinear representation capability, one advantage of this spline in usage is that, once it has been constructed, no parameters need to be tuned to data. We define this spline on the user specified foreground and background pixels, and solve its parameters (the combination coefficients of functions) from a group of linear equations. To speed up spline construction, K-means clustering algorithm is employed to cluster the user specified pixels. By taking the cluster centers as representatives, this spline can be easily constructed. The foreground object is finally cut out from its background via spline interpolation. The computational complexity of the proposed algorithm is linear in the number of the pixels to be segmented. Experiments on diverse natural images, with comparison to existing algorithms, illustrate the validity of our method.

  11. Natural microemulsions: formulation design and skin interaction.

    PubMed

    Schwarz, Julia C; Klang, Victoria; Hoppel, Magdalena; Mahrhauser, Denise; Valenta, Claudia

    2012-08-01

    Microemulsions are thermodynamically stable, colloidal drug delivery systems. This study presents the first substantiated comparison of natural, skin-compatible and biodegradable surfactants in terms of their suitability to form isotropic microemulsions and their skin interaction. Pseudoternery phase diagrams were constructed for lecithin, sucrose laurate and alkylpolyglycoside as single surfactants. Moreover, also mixed surfactant films of lecithin and alkylpolyglycoside as well as lecithin and sucrose laurate were tested. Large isotropic areas could be identified for lecithin, sucrose laurate and lecithin-sucrose laurate. One defined composition was chosen from the pseudoternery phase diagram, prepared with all investigated surfactants and 1:1 surfactant mixtures, respectively, and analysed for their effect on the stratum corneum on a molecular level by ATR-FTIR. Significantly higher frequency values of the symmetric and asymmetric CH(2)-stretching bands compared to the control were recorded for all microemulsions, indicating a hexagonal arrangement of the lipid chains. A similar trend was observed for the lateral packing of the alkyl chains as suggested by the shift of the CH(2)-scissoring bands. Moreover, diffusion cell experiments using porcine skin were performed with the two model drugs flufenamic acid and fluconazole. In both cases, the lecithin-based microemulsions showed the highest permeation rates followed by the alkylpolyglycoside-lecithin microemulsions.

  12. Rethinking adherence.

    PubMed

    Steiner, John F

    2012-10-16

    In 2012, the Centers for Medicare & Medicaid Services (CMS) will introduce measures of adherence to oral hypoglycemic, antihypertensive, and cholesterol-lowering drugs into its Medicare Advantage quality program. To meet these quality goals, delivery systems will need to develop and disseminate strategies to improve adherence. The design of adherence interventions has too often been guided by the mistaken assumptions that adherence is a single behavior that can be predicted from readily available patient characteristics and that individual clinicians alone can improve adherence at the population level.Effective interventions require recognition that adherence is a set of interacting behaviors influenced by individual, social, and environmental forces; adherence interventions must be broadly based, rather than targeted to specific population subgroups; and counseling with a trusted clinician needs to be complemented by outreach interventions and removal of structural and organizational barriers. To achieve the adherence goals set by CMS, front-line clinicians, interdisciplinary teams, organizational leaders, and policymakers will need to coordinate efforts in ways that exemplify the underlying principles of health care reform.

  13. Rethinking wedges

    NASA Astrophysics Data System (ADS)

    Davis, Steven J.; Cao, Long; Caldeira, Ken; Hoffert, Martin I.

    2013-03-01

    ). Wedges expand linearly from 0 to 1 GtC y-1 from 2010 to 2060. The total avoided emissions per wedge is 25 GtC, such that altogether the hidden, stabilization and phase-out wedges represent 775 GtC of cumulative emissions. Unless current climate targets are sacrificed, solving the climate problem requires significantly reducing emissions over the next 50 years. Just how significant those reductions need to be will depend on a global trade-off between the damages imposed by climatic changes and the costs of avoiding them. But given substantial uncertainties associated with climate model projections (e.g., climate sensitivity), the arbitrary nature of targets like 500 ppm and 2 °C, and the permanence implied by the term 'solution', the ultimate solution to the climate problem is a complete phase-out of carbon emissions. 3. Counting wedges But significantly reducing current emissions while also sustaining historical growth rates of the global economy is likely to require many more than seven wedges. Gross world product (GWP) projections embedded in the A2 scenario imply as many as 31 wedges would be required to completely phase-out emissions, grouped into three distinct groups: (1) 12 'hidden' wedges that represent the continued decarbonization of our energy system at historical rates (i.e. decreases in the carbon intensity of the global economy that are assumed to regardless of any additional efforts to mitigate emissions) [9, 39]. (2) 9 'stabilization' wedges that represent additional efforts to mitigate emissions above and beyond the technological progress already assumed by the scenario [1]. And (3), 10 'phase-out' wedges that represent the complete transition from energy infrastructure and land-use practices that emit CO2 (on net) to the atmosphere to infrastructure and practices which do not (figure 2) [9, 14, 40]. There is good reason to be concerned that at least some number of the hidden wedges will not come to be—that the rates of decarbonization assumed by

  14. On the Nature of Interaction in SLA: A Philosophical Stream

    ERIC Educational Resources Information Center

    Maftoon, Parviz; Shakouri, Nima

    2013-01-01

    Researchers have long grappled with situating the stance of interaction in SLA, but it is only recently that interaction has begun to receive consideration from SLA quarters. Delving into the nature of interaction and the prerequisite of interaction in real world, in general, and in classroom, in particular, the authors hold that based on…

  15. Exploring the Nature of Cortical Recurrent Interactions

    NASA Astrophysics Data System (ADS)

    Morita, Kenji; Kalra, Rita; Aihara, Kazuyuki; Robinson, Hugh P. C.

    2011-09-01

    Fast rhythmic activity of neural population has been frequently observed in cortical circuits, and suggested to be associated with various cognitive functions including working memory and selective attention. However, precisely how recurrent synaptic interactions, that are prominent in these circuits, shape and/or modulate such population rhythm has not been fully elucidated. We have addressed this issue by combining electrophysiological and computational approaches.

  16. Rethinking Management Education.

    ERIC Educational Resources Information Center

    French, Robert, Ed.; Grey, Christopher, Ed.

    This book brings together the work of practitioners actively engaged in developing new approaches to management education, and their application. The 10 chapters are: Chapter 1, "Rethinking Management Education: An Introduction" (Christopher Grey and Robert French); chapter 2, "Can Management Education be Educational?" (Alan B. Thomjas and Peter…

  17. Rethinking Early Childhood Education

    ERIC Educational Resources Information Center

    Pelo, Ann, Ed.

    2008-01-01

    "Rethinking Early Childhood Education" is alive with the conviction that teaching young children involves values and vision. This anthology collects inspiring stories about social justice teaching with young children. Included here is outstanding writing from childcare teachers, early-grade public school teachers, scholars, and parents.…

  18. Rethinking Language in Autism

    ERIC Educational Resources Information Center

    Sterponi, Laura; de Kirby, Kenton; Shankey, Jennifer

    2015-01-01

    In this article, we invite a rethinking of traditional perspectives of language in autism. We advocate a theoretical reappraisal that offers a corrective to the dominant and largely tacitly held view that language, in its essence, is a referential system and a reflection of the individual's cognition. Drawing on scholarship in Conversation…

  19. Rethinking the River.

    ERIC Educational Resources Information Center

    Tenenbaum, David

    1994-01-01

    Examines the ecological impacts of the Mississippi River flood of 1993 and the rethinking of river management practices that has resulted. Provides a map of the flood area which shows the occurrence of rare wildlife found in or near the region's rivers. (LZ)

  20. Nature of the effective interaction between dendrimers

    SciTech Connect

    Mandal, Taraknath Dasgupta, Chandan Maiti, Prabal K.

    2014-10-14

    We have performed fully atomistic classical molecular dynamics simulations to calculate the effective interaction between two polyamidoamine dendrimers. Using the umbrella sampling technique, we have obtained the potential of mean force (PMF) between the dendrimers and investigated the effects of protonation level and dendrimer size on the PMF. Our results show that the interaction between the dendrimers can be tuned from purely repulsive to partly attractive by changing the protonation level. The PMF profiles are well-fitted by the sum of an exponential and a Gaussian function with the weight of the exponential function dominating over that of the Gaussian function. This observation is in disagreement with the results obtained in previous analytic [C. Likos, M. Schmidt, H. Löwen, M. Ballauff, D. Pötschke, and P. Lindner, Macromolecules 34, 2914 (2001)] and coarse-grained simulation [I. Götze, H. Harreis, and C. Likos, J. Chem. Phys. 120, 7761 (2004)] studies which predicted the effective interaction to be Gaussian.

  1. Experimental analysis of nature-nurture interactions.

    PubMed

    Wyman, Robert J

    2005-06-01

    The presumed opposition of nature and nurture has been a major concern of western civilization since its beginnings. Christian theologians interpreted Adam and Eve's eating of the forbidden fruit as the origin of an inherited 'original sin'. Saint Augustine explicitly applied the concept to human mental development, arguing that, because of original sin, children are inclined toward evil and education requires physical punishment. For centuries, it was considered parents' moral and religious obligation, not to nurture their children, in our current sense of that word, but to beat the willfulness out of them. 16thC humanists fought back, arguing that "schools have become torture chambers" while it is adults "who corrupt young minds with evil". Locke's (1690) statement that children are born as a 'white paper' was crucial in rejecting the dogma of an inborn (and sinful) nature. The original sin vs. white paper argument merged with another ancient dichotomy: inborn instinct (which controls animal behavior) vs. the reason and free will which humans have. Darwin made the concept of inherited instinct, common to both man and animals, one cornerstone of his theory of evolution. The 20(th)C saw scientists recast the debate as instinct vs. learning, bitterly argued between behaviorists and ethologists. Laboratory experimentation and field observation showed that behavior could develop without learning but also that conditioning paradigms could powerfully mold behavior. The progress of genetics and neurobiology has led to the modern synthesis that neural development, and hence behavior, results from the interdependent action of both heredity and environment.

  2. Natural enemy interactions constrain pest control in complex agricultural landscapes

    PubMed Central

    Martin, Emily A.; Reineking, Björn; Seo, Bumsuk; Steffan-Dewenter, Ingolf

    2013-01-01

    Biological control of pests by natural enemies is a major ecosystem service delivered to agriculture worldwide. Quantifying and predicting its effectiveness at large spatial scales is critical for increased sustainability of agricultural production. Landscape complexity is known to benefit natural enemies, but its effects on interactions between natural enemies and the consequences for crop damage and yield are unclear. Here, we show that pest control at the landscape scale is driven by differences in natural enemy interactions across landscapes, rather than by the effectiveness of individual natural enemy guilds. In a field exclusion experiment, pest control by flying insect enemies increased with landscape complexity. However, so did antagonistic interactions between flying insects and birds, which were neutral in simple landscapes and increasingly negative in complex landscapes. Negative natural enemy interactions thus constrained pest control in complex landscapes. These results show that, by altering natural enemy interactions, landscape complexity can provide ecosystem services as well as disservices. Careful handling of the tradeoffs among multiple ecosystem services, biodiversity, and societal concerns is thus crucial and depends on our ability to predict the functional consequences of landscape-scale changes in trophic interactions. PMID:23513216

  3. Natural enemy interactions constrain pest control in complex agricultural landscapes.

    PubMed

    Martin, Emily A; Reineking, Björn; Seo, Bumsuk; Steffan-Dewenter, Ingolf

    2013-04-02

    Biological control of pests by natural enemies is a major ecosystem service delivered to agriculture worldwide. Quantifying and predicting its effectiveness at large spatial scales is critical for increased sustainability of agricultural production. Landscape complexity is known to benefit natural enemies, but its effects on interactions between natural enemies and the consequences for crop damage and yield are unclear. Here, we show that pest control at the landscape scale is driven by differences in natural enemy interactions across landscapes, rather than by the effectiveness of individual natural enemy guilds. In a field exclusion experiment, pest control by flying insect enemies increased with landscape complexity. However, so did antagonistic interactions between flying insects and birds, which were neutral in simple landscapes and increasingly negative in complex landscapes. Negative natural enemy interactions thus constrained pest control in complex landscapes. These results show that, by altering natural enemy interactions, landscape complexity can provide ecosystem services as well as disservices. Careful handling of the tradeoffs among multiple ecosystem services, biodiversity, and societal concerns is thus crucial and depends on our ability to predict the functional consequences of landscape-scale changes in trophic interactions.

  4. What are the benefits of interacting with nature?

    PubMed

    Keniger, Lucy E; Gaston, Kevin J; Irvine, Katherine N; Fuller, Richard A

    2013-03-06

    There is mounting empirical evidence that interacting with nature delivers measurable benefits to people. Reviews of this topic have generally focused on a specific type of benefit, been limited to a single discipline, or covered the benefits delivered from a particular type of interaction. Here we construct novel typologies of the settings, interactions and potential benefits of people-nature experiences, and use these to organise an assessment of the benefits of interacting with nature. We discover that evidence for the benefits of interacting with nature is geographically biased towards high latitudes and Western societies, potentially contributing to a focus on certain types of settings and benefits. Social scientists have been the most active researchers in this field. Contributions from ecologists are few in number, perhaps hindering the identification of key ecological features of the natural environment that deliver human benefits. Although many types of benefits have been studied, benefits to physical health, cognitive performance and psychological well-being have received much more attention than the social or spiritual benefits of interacting with nature, despite the potential for important consequences arising from the latter. The evidence for most benefits is correlational, and although there are several experimental studies, little as yet is known about the mechanisms that are important for delivering these benefits. For example, we do not know which characteristics of natural settings (e.g., biodiversity, level of disturbance, proximity, accessibility) are most important for triggering a beneficial interaction, and how these characteristics vary in importance among cultures, geographic regions and socio-economic groups. These are key directions for future research if we are to design landscapes that promote high quality interactions between people and nature in a rapidly urbanising world.

  5. What are the Benefits of Interacting with Nature?

    PubMed Central

    Keniger, Lucy E.; Gaston, Kevin J.; Irvine, Katherine N.; Fuller, Richard A.

    2013-01-01

    There is mounting empirical evidence that interacting with nature delivers measurable benefits to people. Reviews of this topic have generally focused on a specific type of benefit, been limited to a single discipline, or covered the benefits delivered from a particular type of interaction. Here we construct novel typologies of the settings, interactions and potential benefits of people-nature experiences, and use these to organise an assessment of the benefits of interacting with nature. We discover that evidence for the benefits of interacting with nature is geographically biased towards high latitudes and Western societies, potentially contributing to a focus on certain types of settings and benefits. Social scientists have been the most active researchers in this field. Contributions from ecologists are few in number, perhaps hindering the identification of key ecological features of the natural environment that deliver human benefits. Although many types of benefits have been studied, benefits to physical health, cognitive performance and psychological well-being have received much more attention than the social or spiritual benefits of interacting with nature, despite the potential for important consequences arising from the latter. The evidence for most benefits is correlational, and although there are several experimental studies, little as yet is known about the mechanisms that are important for delivering these benefits. For example, we do not know which characteristics of natural settings (e.g., biodiversity, level of disturbance, proximity, accessibility) are most important for triggering a beneficial interaction, and how these characteristics vary in importance among cultures, geographic regions and socio-economic groups. These are key directions for future research if we are to design landscapes that promote high quality interactions between people and nature in a rapidly urbanising world. PMID:23466828

  6. Natural Interaction Based Online Military Boxing Learning System

    ERIC Educational Resources Information Center

    Yang, Chenglei; Wang, Lu; Sun, Bing; Yin, Xu; Wang, Xiaoting; Liu, Li; Lu, Lin

    2013-01-01

    Military boxing, a kind of Chinese martial arts, is widespread and health beneficial. In this paper, the authors introduce a military boxing learning system realized by 3D motion capture, Web3D and 3D interactive technologies. The interactions with the system are natural and intuitive. Users can observe and learn the details of each action of the…

  7. Reviewing and visualizing the interactions of natural hazards

    NASA Astrophysics Data System (ADS)

    Gill, Joel C.; Malamud, Bruce D.

    2014-12-01

    This paper presents a broad overview, characterization, and visualization of the interaction relationships between 21 natural hazards, drawn from six hazard groups (geophysical, hydrological, shallow Earth, atmospheric, biophysical, and space hazards). A synthesis is presented of the identified interaction relationships between these hazards, using an accessible visual format particularly suited to end users. Interactions considered are primarily those where a primary hazard triggers or increases the probability of secondary hazards occurring. In this paper we do the following: (i) identify, through a wide-ranging review of grey- and peer-review literature, 90 interactions; (ii) subdivide the interactions into three levels, based on how well we can characterize secondary hazards, given information about the primary hazard; (iii) determine the spatial overlap and temporal likelihood of the triggering relationships occurring; and (iv) examine the relationship between primary and secondary hazard intensities for each identified hazard interaction and group these into five possible categories. In this study we have synthesized, using accessible visualization techniques, large amounts of information drawn from many scientific disciplines. We outline the importance of constraining hazard interactions and reinforce the importance of a holistic (or multihazard) approach to natural hazard assessment. This approach allows those undertaking research into single hazards to place their work within the context of other hazards. It also communicates important aspects of hazard interactions, facilitating an effective analysis by those working on reducing and managing disaster risk within both the policy and practitioner communities.

  8. Natural Interaction Metaphors for Functional Validations of Virtual Car Models.

    PubMed

    Moehring, Mathias; Froehlich, Bernd

    2011-09-01

    Natural Interaction in virtual environments is a key requirement for the virtual validation of functional aspects in automotive product development processes. Natural Interaction is the metaphor people encounter in reality: the direct manipulation of objects by their hands. To enable this kind of Natural Interaction, we propose a pseudophysical metaphor that is both plausible enough to provide realistic interaction and robust enough to meet the needs of industrial applications. Our analysis of the most common types of objects in typical automotive scenarios guided the development of a set of refined grasping heuristics to support robust finger-based interaction of multiple hands and users. The objects' behavior in reaction to the users' finger motions is based on pseudophysical simulations, which also take various types of constrained objects into account. In dealing with real-world scenarios, we had to introduce the concept of Normal Proxies, which extend objects with appropriate normals for improved grasp detection and grasp stability. An expert review revealed that our interaction metaphors allow for an intuitive and reliable assessment of several functionalities of objects found in a car interior. Follow-up user studies showed that overall task performance and usability are similar for CAVE and HMD environments. For larger objects and more gross manipulation, using the CAVE without employing a virtual hand representation is preferred, but for more fine-grained manipulation and smaller objects, the HMD turns out to be beneficial.

  9. Rethinking National Security

    DTIC Science & Technology

    1990-10-01

    WDefnteU N nA8SjIt.. (Colorado Springs. Colo.?): USAF Academy. 1904. (113 790 .10 1984) Sederberg . Peter C . Nuclear Winter. Detertene. MI & h ...ChanginL f f j . Washington: U.S. Dept. of State, 1989. (Gov Does S 1.71/4:1181) Barnett, Frank R., and Carnes Lord. P t Warfare ZjohlLoAarna...Operations: Rethinking b& E & oj k. Washington: GPO, 1989. (Gov Does D 5.402: P 75/2) Barton, John H ., and Ryukiobh Imal. 4W Cntrol L1: & EaRn Af&tqkWA jo

  10. Inferring consistent functional interaction patterns from natural stimulus FMRI data.

    PubMed

    Sun, Jiehuan; Hu, Xintao; Huang, Xiu; Liu, Yang; Li, Kaiming; Li, Xiang; Han, Junwei; Guo, Lei; Liu, Tianming; Zhang, Jing

    2012-07-16

    There has been increasing interest in how the human brain responds to natural stimulus such as video watching in the neuroimaging field. Along this direction, this paper presents our effort in inferring consistent and reproducible functional interaction patterns under natural stimulus of video watching among known functional brain regions identified by task-based fMRI. Then, we applied and compared four statistical approaches, including Bayesian network modeling with searching algorithms: greedy equivalence search (GES), Peter and Clark (PC) analysis, independent multiple greedy equivalence search (IMaGES), and the commonly used Granger causality analysis (GCA), to infer consistent and reproducible functional interaction patterns among these brain regions. It is interesting that a number of reliable and consistent functional interaction patterns were identified by the GES, PC and IMaGES algorithms in different participating subjects when they watched multiple video shots of the same semantic category. These interaction patterns are meaningful given current neuroscience knowledge and are reasonably reproducible across different brains and video shots. In particular, these consistent functional interaction patterns are supported by structural connections derived from diffusion tensor imaging (DTI) data, suggesting the structural underpinnings of consistent functional interactions. Our work demonstrates that specific consistent patterns of functional interactions among relevant brain regions might reflect the brain's fundamental mechanisms of online processing and comprehension of video messages.

  11. Solar-wind interactions - Nature and composition of lunar atmosphere

    NASA Technical Reports Server (NTRS)

    Mukherjee, N. R.

    1975-01-01

    The nature and composition of the lunar atmosphere are examined on the basis of solar-wind interactions, and the nature of the species in the trapped-gas layer is discussed using results of theoretical and experimental investigations. It is shown that the moon has a highly tenuous atmosphere consisting of various species derived from five sources: solar-wind interaction products, cosmic-ray interaction products, effects of meteoritic impacts, planetary degassing, and radioactive-decay products. Atmospheric concentrations are determined for those species derived from solar-wind protons, alpha particles, and oxygen ions. Carbon chemistry is briefly discussed, and difficulties encountered in attempts to determine quantitatively the concentrations of molecular oxygen, atomic oxygen, carbon monoxide, carbon dioxide, and methane are noted. The calculated concentrations are shown to be in good agreement with observations by the Apollo 17 lunar-surface mass spectrometer and orbital UV spectrometer.

  12. Groundwater surface water interaction study using natural isotopes tracer

    NASA Astrophysics Data System (ADS)

    Yoon, Yoon Yeol; Kim, Yong Chul; Cho, Soo Young; Lee, Kil Yong

    2015-04-01

    Tritium and stable isotopes are a component of the water molecule, they are the most conservative tracer for groundwater study. And also, radon is natural radioactive nuclide and well dissolved in groundwater. Therefore, these isotopes are used natural tracer for the study of surface water and groundwater interaction of water curtain greenhouse area. The study area used groundwater as a water curtain for warming tool of greenhouse during the winter, and is associated with issues of groundwater shortage while being subject to groundwater-river water interaction. During the winter time, these interactions were studied by using Rn-222, stable isotopes and H-3. These interaction was monitored in multi depth well and linear direction well of groundwater flow. And dam effect was also compared. Samples were collected monthly from October 2013 to April 2014. Radon and tritium were analyzed using Quantulus low background liquid scintillation counter and stable isotopes were analyzed using an IRIS (Isotope Ratio Infrared Spectroscopy ; L2120-i, Picarro). During the winter time, radon concentration was varied from 0.07 Bq/L to 8.9 Bq/L and different interaction was showed between dam. Surface water intrusion was severe at February and restored April when greenhouse warming was ended. The stable isotope results showed different trend with depth and ranged from -9.16 ‰ to -7.24 ‰ for δ 18O value, while the δD value was ranged from -57.86 ‰ to -50.98 ‰. The groundwater age as dated by H-3 was ranged 0.23 Bq/L - 0.59 Bq/L with an average value of 0.37 Bq/L.

  13. Natural Rubber-Filler Interactions: What Are the Parameters?

    PubMed

    Chan, Alan Jenkin; Steenkeste, Karine; Canette, Alexis; Eloy, Marie; Brosson, Damien; Gaboriaud, Fabien; Fontaine-Aupart, Marie-Pierre

    2015-11-17

    Reinforcement of a polymer matrix through the incorporation of nanoparticles (fillers) is a common industrial practice that greatly enhances the mechanical properties of the composite material. The origin of such mechanical reinforcement has been linked to the interaction between the polymer and filler as well as the homogeneous dispersion of the filler within the polymer matrix. In natural rubber (NR) technology, knowledge of the conditions necessary to achieve more efficient NR-filler interactions is improving continuously. This study explores the important physicochemical parameters required to achieve NR-filler interactions under dilute aqueous conditions by varying both the properties of the filler (size, composition, surface activity, concentration) and the aqueous solution (ionic strength, ion valency). By combining fluorescence and electron microscopy methods, we show that NR and silica interact only in the presence of ions and that heteroaggregation is favored more than homoaggregation of silica-silica or NR-NR. The interaction kinetics increases with the ion valence, whereas the morphology of the heteroaggregates depends on the size of silica and the volume percent ratio (dry silica/dry NR). We observe dendritic structures using silica with a diameter (d) of 100 nm at a ∼20-50 vol % ratio, whereas we obtain raspberry-like structures using silica with d = 30 nm particles. We observe that in liquid the interaction is controlled by the hydrophilic bioshell, in contrast to dried conditions, where hydrophobic polymer dominates the interaction of NR with the fillers. A good correlation between the nanoscopic aggregation behavior and the macroscopic aggregation dynamics of the particles was observed. These results provide insight into improving the reinforcement of a polymer matrix using NR-filler films.

  14. Econo-Thermodynamics: The Nature of Economic Interactions

    NASA Astrophysics Data System (ADS)

    Mimkes, Juergen

    2006-03-01

    Physicists often model economic interactions like collisions of atoms in gases: by interaction one agent gains, the other loses. This leads to a Boltzmann distribution of capital, which has been observed in wealth distributions of different countries. However, economists object: no economic agent will attend a market in which he gets robbed! This conflict may be resolved by writing basic laws of economics into terms of calculus. In these terms the daily struggle for survival of all economic systems turns out to be a Carnot cycle that is driven by energy: heat pumps and economic production depend on oil, GNP and oil consumption run parallel for all countries. Motors and markets are based on the same laws of calculus (macro-economics) and statistics (micro-economics). Economic interactions mean exploiting a third party (nature) and are indeed close to robbing! A baker sells bread to his customers, but the flour comes from nature. Banks sells loans to investors, but the money comes from savers. Econo-thermodynamics is a thrilling new interdisciplinary field.

  15. Interactions between plasma proteins and naturally occurring polyphenols.

    PubMed

    Li, Min; Hagerman, Ann E

    2013-05-01

    The plant natural products known as polyphenols are found at micronutrient levels in fruits, vegetables, and plant-based beverages such as wine, tea, coffee and cocoa. Consumption of a fruit- and vegetable-rich diet, the "Mediterranean diet", has been epidemiologically related to health benefits especially for chronic diseases including diabetes, cardiovascular disease, and Alzheimer's disease. The abundance of polyphenols in plant-rich diets, and the potent bioactivities of polyphenols, provide indirect evidence for a role for polyphenols in maintaining good health. However, molecular mechanisms for therapeutic or preventative activity have not been demonstrated in vivo. We summarize the chemical classes of natural polyphenols, their bioactivities and bioavailability and metabolism. Because many polyphenols bind protein, we focus on the potential of protein binding to mediate the health-related effects of polyphenols. We discuss interactions with plasma proteins as the first target organ past the digestive tract for these orally-ingested compounds.

  16. Smoking and COPD: the impact of nature-nurture interactions.

    PubMed

    Clancy, John; Turner, Christopher

    The maintenance of health (homeostasis) and the occurrence of disease such as chronic obstructive pulmonary disease (COPD) are acquired through nature-nurture interactions. The inherited genotype of a person is responsible for producing a deficiency of enzymes called anti-proteases, such as alpha-1 antitrypsin, which protect lung tissue--or for producing an excess of enzymes, such as proteases, which destroy lung tissue. Smoking is discussed in this paper, since it is a major risk factor in the development of COPD, a condition affecting 3 million people in the UK. Research into genetics is beginning to indicate that smoking behaviour may be linked to some form of genetic disposition. Such an association would help health professionals deliver a more patient-centred smoking cessation service. This paper argues that the nurse, in this educator role, can only be considered a partial agent of homeostatic control with patients who have COPD, due to the progressive nature of this disease.

  17. Organic matter interactions with natural manganese oxide and synthetic birnessite.

    PubMed

    Allard, Sébastien; Gutierrez, Leonardo; Fontaine, Claude; Croué, Jean-Philippe; Gallard, Hervé

    2017-04-01

    Redox reactions of inorganic and organic contaminants on manganese oxides have been widely studied. However, these reactions are strongly affected by the presence of natural organic matter (NOM) at the surface of the manganese oxide. Interestingly, the mechanism behind NOM adsorption onto manganese oxides remains unclear. Therefore, in this study, the adsorption kinetics and equilibrium of different NOM isolates to synthetic manganese oxide (birnessite) and natural manganese oxide (Mn sand) were investigated. Natural manganese oxide is composed of both amorphous and well-crystallised Mn phases (i.e., lithiophorite, birnessite, and cryptomelane). NOM adsorption on both manganese oxides increased with decreasing pH (from pH7 to 5), in agreement with surface complexation and ligand exchange mechanisms. The presence of calcium enhanced the rate of NOM adsorption by decreasing the electrostatic repulsion between NOM and Mn sand. Also, the adsorption was limited by the diffusion of NOM macromolecules through the Mn sand pores. At equilibrium, a preferential adsorption of high molecular weight molecules enriched in aromatic moieties was observed for both the synthetic and natural manganese oxide. Hydrophobic interactions may explain the adsorption of organic matter on manganese oxides. The formation of low molecular weight UV absorbing molecules was detected with the synthetic birnessite, suggesting oxidation and reduction processes occurring during NOM adsorption. This study provides a deep insight for both environmental and engineered systems to better understand the impact of NOM adsorption on the biogeochemical cycle of manganese.

  18. Self-interacting dark matter with naturally light mediator

    NASA Astrophysics Data System (ADS)

    Ma, Ernest

    2017-02-01

    A promising proposal for resolving the cusp-core anomaly in the density profile of dwarf galaxies is to allow dark matter to interact with itself through a light mediator of mass much less than a GeV. The theoretical challenge is to have a complete renormalizable theory where this happens naturally even though dark matter itself may be of the electroweak scale, i.e. 100 GeV to 1 TeV. I propose here such a model with just two neutral complex scalar singlets under a softly broken dark global U(1) symmetry.

  19. Re-thinking residential mobility

    PubMed Central

    van Ham, Maarten; Findlay, Allan M.

    2015-01-01

    While researchers are increasingly re-conceptualizing international migration, far less attention has been devoted to re-thinking short-distance residential mobility and immobility. In this paper we harness the life course approach to propose a new conceptual framework for residential mobility research. We contend that residential mobility and immobility should be re-conceptualized as relational practices that link lives through time and space while connecting people to structural conditions. Re-thinking and re-assessing residential mobility by exploiting new developments in longitudinal analysis will allow geographers to understand, critique and address pressing societal challenges. PMID:27330243

  20. Modeling insurer-homeowner interactions in managing natural disaster risk.

    PubMed

    Kesete, Yohannes; Peng, Jiazhen; Gao, Yang; Shan, Xiaojun; Davidson, Rachel A; Nozick, Linda K; Kruse, Jamie

    2014-06-01

    The current system for managing natural disaster risk in the United States is problematic for both homeowners and insurers. Homeowners are often uninsured or underinsured against natural disaster losses, and typically do not invest in retrofits that can reduce losses. Insurers often do not want to insure against these losses, which are some of their biggest exposures and can cause an undesirably high chance of insolvency. There is a need to design an improved system that acknowledges the different perspectives of the stakeholders. In this article, we introduce a new modeling framework to help understand and manage the insurer's role in catastrophe risk management. The framework includes a new game-theoretic optimization model of insurer decisions that interacts with a utility-based homeowner decision model and is integrated with a regional catastrophe loss estimation model. Reinsurer and government roles are represented as bounds on the insurer-insured interactions. We demonstrate the model for a full-scale case study for hurricane risk to residential buildings in eastern North Carolina; present the results from the perspectives of all stakeholders-primary insurers, homeowners (insured and uninsured), and reinsurers; and examine the effect of key parameters on the results.

  1. Chronic obstructive pulmonary disease: nature-nurture interactions.

    PubMed

    Clancy, John; Nobes, Maggie

    A person's health status is rarely constant, it is usually subject to continual change as a person moves from health to illness and usually back to health again; the health-illness continuum illustrates this dynamism. This highlights the person's various states of health and illness (ranging from extremely good health to clinically defined mild, moderate and severe illness) and their fluctuations throughout the life span, until ultimately leading to the pathology associated with the person's death. Maintenance of a stable homeostatic environment within the body to support the stability of this continuum depends on a complex series of ultimately intracellular chemical reactions. These reactions are activated by environmental factors that cause the expression of genes associated with healthy phenotypes as well as illness susceptibility genes associated with homeostatic imbalances. Obviously, the body aims to support intracellular and extracellular environments allied with health; however, the complexity of these nature-nurture interactions results in illness throughout an individual's life span. This paper will discuss the nature-nurture interactions of chronic obstructive pulmonary disease.

  2. Sparse codes of harmonic natural sounds and their modulatory interactions.

    PubMed

    Terashima, Hiroki; Hosoya, Haruo

    2009-01-01

    Sparse coding and its related theories have been successful to explain various response properties of early stages of sensory information processing such as primary visual cortex and peripheral auditory system, which suggests that the emergence of such properties results from adaptation of the nerve system to natural stimuli. The present study continues this line of research in a higher stage of auditory processing, focusing on harmonic structures that are often found in behaviourally important natural sound like animal vocalization. It has been physiologically shown that monkey primary auditory cortices (A1) have neurons with response properties capturing such harmonic structures: their response and modulation peaks are often found at frequencies that are harmonically related to each other. We hypothesize that such relations emerge from sparse coding of harmonic natural sounds. Our simulation shows that similar harmonic relations emerge from frequency-domain sparse codes of harmonic sounds, namely, piano performance and human speech. Moreover, the modulatory behaviours can be explained by competitive interactions of model neurons that capture partially common harmonic structures.

  3. Newtonian cell interactions shape natural killer cell education.

    PubMed

    Goodridge, Jodie P; Önfelt, Björn; Malmberg, Karl-Johan

    2015-09-01

    Newton's third law of motion states that for every action on a physical object there is an equal and opposite reaction. The dynamic change in functional potential of natural killer (NK) cells during education bears many features of such classical mechanics. Cumulative physical interactions between cells, under a constant influence of homeostatic drivers of differentiation, lead to a reactive spectrum that ultimately shapes the functionality of each NK cell. Inhibitory signaling from an array of self-specific receptors appear not only to suppress self-reactivity but also aid in the persistence of effector functions over time, thereby allowing the cell to gradually build up a functional potential. Conversely, the frequent non-cytolytic interactions between normal cells in the absence of such inhibitory signaling result in continuous stimulation of the cells and attenuation of effector function. Although an innate cell, the degree to which the fate of the NK cell is predetermined versus its ability to adapt to its own environment can be revealed through a Newtonian view of NK cell education, one which is both chronological and dynamic. As such, the development of NK cell functional diversity is the product of qualitatively different physical interactions with host cells, rather than simply the sum of their signals or an imprint based on intrinsically different transcriptional programs.

  4. Interacting vs. non-interacting single domain behavior in natural and synthetic samples

    NASA Technical Reports Server (NTRS)

    Cisowski, S.

    1981-01-01

    The disparity in response to high alternating field (AF) demagnetization for samples containing fine magnetic carriers is apparently related to the degree of interactions between those carriers. The presence of interaction fields between single domain (SD) grains can be tested by plotting isothermal remanence (IRM) acquisition vs. saturation remanence (SIRM) demagnetization. For the case of noninteracting SD grains, the two curves will be symmetrical. For the interacting SD case, the acquisition curve will be steepest at higher field, and the demagnetization curve steepest at lower fields, resulting in nonsymmetry. The point of intersection of the two curves approximates the remanent coercive force (H sub RC) field for all cases. Minor hysteresis loops and anhysteretic remanence (ARM) acquisition curves are also strongly influenced by interaction fields. Because of the difficulty in dispersing strongly magnetic grains, fine grained synthetic samples made with highly magnetic materials will not display equivalent AF stability to natural samples with fine, dispersed grains.

  5. Rethinking Popular Culture and Media

    ERIC Educational Resources Information Center

    Marshall, Elizabeth, Ed.; Sensoy, Ozlem, Ed.

    2011-01-01

    "Rethinking Popular Culture and Media" is a provocative collection of articles that begins with the idea that the "popular" in classrooms and in the everyday lives of teachers and students is fundamentally political. This anthology includes outstanding articles by elementary and secondary public school teachers, scholars, and activists who…

  6. The Birth of Rethinking Schools

    ERIC Educational Resources Information Center

    Peterson, Bob

    2011-01-01

    The author often says that Rethinking Schools began on his kitchen table with a can of rubber cement and an Apple IIe computer. But that's not exactly true. In some ways the publication started a year and half earlier in a study group of teachers and community activists who were struggling to figure out how to apply a generally progressive,…

  7. Modeling Gene-Environment Interactions With Quasi-Natural Experiments.

    PubMed

    Schmitz, Lauren; Conley, Dalton

    2017-02-01

    This overview develops new empirical models that can effectively document Gene × Environment (G×E) interactions in observational data. Current G×E studies are often unable to support causal inference because they use endogenous measures of the environment or fail to adequately address the nonrandom distribution of genes across environments, confounding estimates. Comprehensive measures of genetic variation are incorporated into quasi-natural experimental designs to exploit exogenous environmental shocks or isolate variation in environmental exposure to avoid potential confounders. In addition, we offer insights from population genetics that improve upon extant approaches to address problems from population stratification. Together, these tools offer a powerful way forward for G×E research on the origin and development of social inequality across the life course.

  8. Rethinking the 2000 ACRL Standards: Some Things to Consider

    ERIC Educational Resources Information Center

    Kuhlthau, Carol C.

    2013-01-01

    I propose three "rethinks" to consider in recasting the ACRL Standards for information literacy for the coming decades. First, rethink the concept of information need. Second, rethink the notion that information literacy is composed of a set of abilities for "extracting information." Third, rethink the holistic process of…

  9. Rethinking Multicultural Education: Teaching for Racial and Cultural Justice

    ERIC Educational Resources Information Center

    Au, Wayne, Ed.

    2009-01-01

    Since the 1980s, "Rethinking Schools" magazine has been renowned for its commitment to racial equality in education. Now, "Rethinking Multicultural Education: Teaching for Racial and Cultural Justice" has collected the best Rethinking Schools articles that deal with race and culture. "Rethinking Multicultural…

  10. Interfacial interactions between natural RBC membranes and synthetic polymeric nanoparticles

    NASA Astrophysics Data System (ADS)

    Luk, Brian T.; Jack Hu, Che-Ming; Fang, Ronnie H.; Dehaini, Diana; Carpenter, Cody; Gao, Weiwei; Zhang, Liangfang

    2014-02-01

    The unique structural features and stealth properties of a recently developed red blood cell membrane-cloaked nanoparticle (RBC-NP) platform raise curiosity over the interfacial interactions between natural cellular membranes and polymeric nanoparticle substrates. Herein, several interfacial aspects of the RBC-NPs are examined, including completeness of membrane coverage, membrane sidedness upon coating, and the effects of polymeric particles' surface charge and surface curvature on the membrane cloaking process. The study shows that RBC membranes completely cover negatively charged polymeric nanoparticles in a right-side-out manner and enhance the particles' colloidal stability. The membrane cloaking process is applicable to particle substrates with a diameter ranging from 65 to 340 nm. Additionally, the study reveals that both surface glycans on RBC membranes and the substrate properties play a significant role in driving and directing the membrane-particle assembly. These findings further the understanding of the dynamics between cellular membranes and nanoscale substrates and provide valuable information toward future development and characterization of cellular membrane-cloaked nanodevices.The unique structural features and stealth properties of a recently developed red blood cell membrane-cloaked nanoparticle (RBC-NP) platform raise curiosity over the interfacial interactions between natural cellular membranes and polymeric nanoparticle substrates. Herein, several interfacial aspects of the RBC-NPs are examined, including completeness of membrane coverage, membrane sidedness upon coating, and the effects of polymeric particles' surface charge and surface curvature on the membrane cloaking process. The study shows that RBC membranes completely cover negatively charged polymeric nanoparticles in a right-side-out manner and enhance the particles' colloidal stability. The membrane cloaking process is applicable to particle substrates with a diameter ranging from

  11. The nature of electrical interaction of Schottky contacts

    SciTech Connect

    Torkhov, N. A.

    2011-08-15

    Electrical interaction between metal-semiconductor contacts combined in a diode matrix with a Schottky barrier manifests itself in an appreciable variation in their surface potentials and static current-volt-characteristics. The necessary condition for appearance of electrical interaction between such contacts consists in the presence of a peripheral electric field (a halo) around them; this field propagates to a fairly large distances (<30 {mu}m). The sufficient condition is the presence of regions where the above halos overlap. It has been shown that variation in the surface potential and the current-voltage characteristics of contacts occurs under the effect of the intrinsic electric field of the contact's periphery and also under the effect of an electric field at matrix periphery; the latter field is formed as a result of superposition of electric fields of halos which form its contacts. The degree of the corresponding effect is governed by the distance between contacts and by the total charge of the space charge regions for all contacts of the matrix: their number, sizes (diameter D{sub i,j}), concentration of doping impurities in the semiconductor N{sub D}, and physical nature of a metal-semiconductor system with a Schottky barrier (with the barrier height {phi}{sub b}). It is established that bringing the contacts closer leads to a relative decrease in the threshold value of the 'dead' zone in the forward current-voltage characteristics, an increase in the effective height of the barrier, and an insignificant increase in the nonideality factor. An increase in the total area of contacts (a total electric charge in the space charge region) in the matrix brings about an increase in the threshold value of the 'dead' zone, a relative decrease in the effective barrier height, and an insignificant increase in the ideality factor.

  12. Rethinking Schools and the Power of Silver

    ERIC Educational Resources Information Center

    Sleeter, Christine

    2011-01-01

    This 25th anniversary of "Rethinking Schools" can be thought of as its silver anniversary. Silver itself must be considered through contrasting lenses. On the one hand, as lessons in "Rethinking Globalization" teach, silver and gold were the basis of Europe's horrendous exploitation of Latin America. On the other hand, silver is often associated…

  13. A Natural Interaction Interface for UAVs Using Intuitive Gesture Recognition

    NASA Technical Reports Server (NTRS)

    Chandarana, Meghan; Trujillo, Anna; Shimada, Kenji; Allen, Danette

    2016-01-01

    The popularity of unmanned aerial vehicles (UAVs) is increasing as technological advancements boost their favorability for a broad range of applications. One application is science data collection. In fields like Earth and atmospheric science, researchers are seeking to use UAVs to augment their current portfolio of platforms and increase their accessibility to geographic areas of interest. By increasing the number of data collection platforms UAVs will significantly improve system robustness and allow for more sophisticated studies. Scientists would like be able to deploy an available fleet of UAVs to fly a desired flight path and collect sensor data without needing to understand the complex low-level controls required to describe and coordinate such a mission. A natural interaction interface for a Ground Control System (GCS) using gesture recognition is developed to allow non-expert users (e.g., scientists) to define a complex flight path for a UAV using intuitive hand gesture inputs from the constructed gesture library. The GCS calculates the combined trajectory on-line, verifies the trajectory with the user, and sends it to the UAV controller to be flown.

  14. Outer satellite atmospheres: Their nature and planetary interactions

    NASA Technical Reports Server (NTRS)

    Smyth, W. H.; Combi, M. R.

    1984-01-01

    Significant insights regarding the nature and interactions of Io and the planetary magnetosphere were gained through modeling studies of the spatial morphology and brightness of the Io sodium cloud. East-west intensity asymmetries in Region A are consistent with an east-west electric field and the offset of the magnetic and planetary-spin axes. East-west orbital asymmetries and the absolute brightness of Region B suggest a low-velocity (3 km/sec) satellite source of 1 to 2 x 10(26) sodium atoms/sec. The time-varying spatial structure of the sodium directional features in near Region C provides direct evidence for a magnetospheric-wind-driven escape mechanism with a high-velocity (20 km/sec) source of 1 x 10(26) atoms/sec and a flux distribution enhanced at the equator relative to the poles. A model for the Io potassium cloud is presented and analysis of data suggests a low velocity source rate of 5 x 10(24) atoms/sec. To understand the role of Titan and non-Titan sources for H atoms in the Saturn system, the lifetime of hydrogen in the planetary magnetosphere was incorporated into the earlier Titan torus model of Smyth (1981) and its expected impact discussed. A particle trajectory model for cometary hydrogen is presented and applied to the Lyman-alpha distribution of Comet Kohoutek (1973XII).

  15. Natural and pyrogenic humic acids at goethite and natural oxide surfaces interacting with phosphate.

    PubMed

    Hiemstra, Tjisse; Mia, Shamim; Duhaut, Pierre-Benoît; Molleman, Bastiaan

    2013-08-20

    Fulvic and humic acids have a large variability in binding to metal (hydr) oxide surfaces and interact differently with oxyanions, as examined here experimentally. Pyrogenic humic acid has been included in our study since it will be released to the environment in the case of large-scale application of biochar, potentially creating Darks Earths or Terra Preta soils. A surface complexation approach has been developed that aims to describe the competitive behavior of natural organic matter (NOM) in soil as well as model systems. Modeling points unexpectedly to a strong change of the molecular conformation of humic acid (HA) with a predominant adsorption in the Stern layer domain at low NOM loading. In soil, mineral oxide surfaces remain efficiently loaded by mineral-protected organic carbon (OC), equivalent with a layer thickness of ≥ ~0.5 nm that represents at least 0.1-1.0% OC, while surface-associated OC may be even three times higher. In natural systems, surface complexation modeling should account for this pervasive NOM coverage. With our charge distribution model for NOM (NOM-CD), the pH-dependent oxyanion competition of the organo-mineral oxide fraction can be described. For pyrogenic HA, a more than 10-fold increase in dissolved phosphate is predicted at long-term applications of biochar or black carbon.

  16. Interfacial interaction between the epoxidized natural rubber and silica in natural rubber/silica composites

    NASA Astrophysics Data System (ADS)

    Xu, Tiwen; Jia, Zhixin; Luo, Yuanfang; Jia, Demin; Peng, Zheng

    2015-02-01

    The epoxidized natural rubber (ENR) as an interfacial modifier was used to improve the mechanical and dynamical mechanical properties of NR/silica composites. In order to reveal the interaction mechanism between ENR and silica, the ENR/Silica model compound was prepared by using an open mill and the interfacial interaction of ENR with silica was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and stress-strain testing. The results indicated that the ring-opening reaction occurs between the epoxy groups of ENR chains and Si-OH groups on the silica surfaces and the covalent bonds are formed between two phases, which can improve the dispersion of silica in the rubber matrix and enhance the interfacial combination between rubber and silica. The ring-opening reaction occurs not only in vulcanization process but also in mixing process, meanwhile, the latter seems to be more important due to the simultaneous effects of mechanical force and temperature.

  17. Insights From Natural Host-Parasite Interactions: The Drosophila Model

    PubMed Central

    Keebaugh, Erin S.; Schlenke, Todd A.

    2013-01-01

    Immune responses against opportunistic pathogens have been extensively studied in Drosophila, leading to a detailed map of the genetics behind innate immunity networks including the Toll, Imd, Jak-Stat, and JNK pathways. However, immune mechanisms of other organisms, particularly plants, have primarily been investigated using natural pathogens. It was the use of natural pathogens in plant research that revealed the plant R/Avr system, a specialized immune response derived from antagonistic coevolution between plant immune proteins and their natural pathogens’ virulence proteins. Thus, we recommend that researchers begin to use natural Drosophila pathogens to identify novel immune mechanisms that may have arisen through antagonistic coevolution with common natural pathogens. In this review, we address the benefits of using natural pathogens in research, describe the known natural pathogens of Drosophila, and discuss exciting prospects for future research on select natural pathogens of Drosophila. PMID:23764256

  18. Geothermal field's interaction with geophysical fields of another nature

    SciTech Connect

    Novik, Oleg B.; Mikhailovskaya, Irina B.; Repin, Dmitry G.; Yershov, Sergey V.

    1996-01-24

    The energy balance of active lithosphere zones is to a large extent determined by nonstationary interaction of mechanical (elastic and hydrodynamic), thermal, electromagnetic, and gravitational geophysical fields. Seismic disturbances of electromagnetic and temperature fields, repeatedly observed before earthquakes are a striking manifestation of this interaction (Sec. 1). Technological processes of exploitation of hydrothermal deposits are determined by the interaction of hydrodynamical and temperature field (Sec. 2). These “fast” interactions (with the characteristic time scale from seconds to years) take place against the background of “slow” thermomechanical interactions (time scale of Myears), the latter determining the formation of regional geothermal fields (Sec. 3).

  19. Interactions in Natural Colloid Systems "Biosolids" - Soil and Plant

    NASA Astrophysics Data System (ADS)

    Kalinichenko, Kira V.; Nikovskaya, Galina N.; Ulberg, Zoya R.

    2016-04-01

    The "biosolids" are complex biocolloid system arising in huge amounts (mln tons per year) from biological municipal wastewater treatment. These contain clusters of nanoparticles of heavy metal compounds (in slightly soluble or unsoluble forms, such as phosphates, sulphates, carbonates, hydroxides, and etc.), cells, humic substances and so on, involved in exopolysaccharides (EPS) net matrix. One may consider that biosolids are the natural nanocomposite. Due to the presence of nitrogen, phosphorus, potassium and other macro- and microelements (heavy metals), vitamins, aminoacids, etc., the biosolids are a depot of bioelements for plant nutrition. Thus, it is generally recognized that most rationally to utilize them for land application. For this purpose the biocolloid process was developed in biosolids system by initiation of microbial vital ability followed by the synthesis of EPS, propagation of ecologically important microorganisms, loosening of the structure and weakening of the coagulation contacts between biosolids colloids, but the structure integrity maintaining [1,2]. It was demonstrated that the applying of biosolids with metabolizing microorganisms to soil provided the improving soil structure, namely the increasing of waterstable aggregates content (70% vs. 20%). It occurs due to flocculation ability of biosolids EPS. The experimental modelling of mutual interactions in systems of soils - biosolids (with metabolizing microorganisms) were realized and their colloid and chemical mechanisms were formulated [3]. As it is known, the most harmonious plant growth comes at a prolonged entering of nutrients under the action of plant roots exudates which include pool of organic acids and polysaccharides [4]. Special investigations showed that under the influence of exudates excreted by growing plants, the biosolids microelements can release gradually from immobilized state into environment and are able to absorb by plants. Thus, the biosolids can serve as an active

  20. Natural gas storage - end user interaction. Task 2. Topical report

    SciTech Connect

    1996-01-01

    New opportunities have been created for underground gas storage as a result of recent regulatory developments in the energy industry. The Federal Energy Regulatory Commission (FERC) Order 636 directly changed the economics of gas storage nationwide. This paper discusses the storage of natural gas, storage facilities, and factors affecting the current, and future situation for natural gas storage.

  1. Interface interactions of natural rubber and protein/fiber aggregates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mechanical properties of natural rubber are improved with a renewable filler for rubber applications. Aggregates of protein and fiber that constitute soy protein concentrate were shear-reduced and used to enhance the tensile modulus of the natural rubber. The aqueous dispersion of the shear-reduced ...

  2. Local nature of substituent effects in stacking interactions.

    PubMed

    Wheeler, Steven E

    2011-07-06

    Popular explanations of substituent effects in π-stacking interactions hinge upon substituent-induced changes in the aryl π-system. This entrenched view has been used to explain substituent effects in countless stacking interactions over the past 2 decades. However, for a broad range of stacked dimers, it is shown that substituent effects are better described as arising from local, direct interactions of the substituent with the proximal vertex of the other ring. Consequently, substituent effects in stacking interactions are additive, regardless of whether the substituents are on the same or opposite rings. Substituent effects are also insensitive to the introduction of heteroatoms on distant parts of either stacked ring. This local, direct interaction viewpoint provides clear, unambiguous explanations of substituent effects for myriad stacking interactions that are in accord with robust computational data, including DFT-D and new benchmark CCSD(T) results. Many of these computational results cannot be readily explained using traditional π-polarization-based models. Analyses of stacking interactions based solely on the sign of the electrostatic potential above the face of an aromatic ring or the molecular quadrupole moment face a similar fate. The local, direct interaction model provides a simple means of analyzing substituent effects in complex aromatic systems and also offers simple explanations of the crystal packing of fluorinated benzenes and the recently published dependence of the stability of protein-RNA complexes on the regiochemistry of fluorinated base analogues [J. Am. Chem. Soc.2011, 133, 3687-3689].

  3. A unifying framework for quantifying the nature of animal interactions

    PubMed Central

    Potts, Jonathan R.; Mokross, Karl; Lewis, Mark A.

    2014-01-01

    Collective phenomena, whereby agent–agent interactions determine spatial patterns, are ubiquitous in the animal kingdom. On the other hand, movement and space use are also greatly influenced by the interactions between animals and their environment. Despite both types of interaction fundamentally influencing animal behaviour, there has hitherto been no unifying framework for the models proposed in both areas. Here, we construct a general method for inferring population-level spatial patterns from underlying individual movement and interaction processes, a key ingredient in building a statistical mechanics for ecological systems. We show that resource selection functions, as well as several examples of collective motion models, arise as special cases of our framework, thus bringing together resource selection analysis and collective animal behaviour into a single theory. In particular, we focus on combining the various mechanistic models of territorial interactions in the literature with step selection functions, by incorporating interactions into the step selection framework and demonstrating how to derive territorial patterns from the resulting models. We demonstrate the efficacy of our model by application to a population of insectivore birds in the Amazon rainforest. PMID:24829284

  4. A unifying framework for quantifying the nature of animal interactions.

    PubMed

    Potts, Jonathan R; Mokross, Karl; Lewis, Mark A

    2014-07-06

    Collective phenomena, whereby agent-agent interactions determine spatial patterns, are ubiquitous in the animal kingdom. On the other hand, movement and space use are also greatly influenced by the interactions between animals and their environment. Despite both types of interaction fundamentally influencing animal behaviour, there has hitherto been no unifying framework for the models proposed in both areas. Here, we construct a general method for inferring population-level spatial patterns from underlying individual movement and interaction processes, a key ingredient in building a statistical mechanics for ecological systems. We show that resource selection functions, as well as several examples of collective motion models, arise as special cases of our framework, thus bringing together resource selection analysis and collective animal behaviour into a single theory. In particular, we focus on combining the various mechanistic models of territorial interactions in the literature with step selection functions, by incorporating interactions into the step selection framework and demonstrating how to derive territorial patterns from the resulting models. We demonstrate the efficacy of our model by application to a population of insectivore birds in the Amazon rainforest.

  5. Rethinking Virtual Reference

    ERIC Educational Resources Information Center

    Tenopir, Carol

    2004-01-01

    Virtual reference services seem a natural extension of libraries digital collections and the emphasis on access to the library anytime, anywhere. If patrons use the library from home, it makes sense to provide them with person-to-person online reference. The Library of Congress (LC), OCLC, and several large library systems have developed and…

  6. A Simple Model for Human and Nature Interaction

    NASA Astrophysics Data System (ADS)

    Motesharrei, S.; Rivas, J.; Kalnay, E.

    2012-12-01

    There are widespread concerns that current trends in population and resource-use are unsustainable, but the possibilities of an overshoot and collapse remain unclear and controversial. Collapses of civilizations have occurred many times in the past 5000 years, often followed by centuries of economic, intellectual, and population decline. Many different natural and social phenomena have been invoked to explain specific collapses, but a general explanation remains elusive. Two important features seem to appear across societies that have collapsed: Ecological Strain and Economic Stratification. Our new model (Human And Nature DYnamics, HANDY) has just four equations that describe the evolution of Elites, Commoners, Nature, and Wealth. Mechanisms leading to collapse are discussed and the measure "Carrying Capacity" is developed and defined. The model shows that societal collapse can happen due to either one of two independent factors: (1) over-consumption of natural resources, and/or (2) deep inequity between Elites and Commoners. The model also portrays two distinct types of collapse: (i) collapse followed by recovery of nature, and (ii) full collapse. The model suggests that the estimation of Carrying Capacity is a practical means for early detection of a collapse. Collapse can be avoided, and population can reach a sustainable equilibrium, if the rate of depletion of nature is reduced to a sustainable level, and if resources are distributed in a reasonably equitable fashion.; A type-ii (full) collapse is shown in this figure. With high inequality and high depletion, societies are doomed to collapse. Wealth starts to decrease when population rises above the carrying capacity. The large gap between carrying capacity and its maximum is a result of depletion factor being much larger than the sustainable limit. ; It is possible to overshoot, oscillate, and eventually converge to an equilibrium, even in an inequitable society. However, it requires policies that control

  7. Rethinking Resources: Multimodal Pedagogies in the ESL Classroom.

    ERIC Educational Resources Information Center

    Stein, Pippa

    2000-01-01

    Describes a process for rethinking resources in the English-as-a-Second-Language classroom. Rethinking resources is possible through multimodal pedagogies that recognize students as remakers and transformers of the representational resources available to them. (Author/VWL)

  8. Molecular Diagnosis of Natural enemy-host Interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The cryptic behaviors, small size, and rapid movement and feeding actions of arthropod natural enemies dictate the need for alternative technologies for the study of trophic linkages to replace the traditional approaches of direct observation and laboratory experimentation. Many molecular approaches...

  9. On the nature of the solar-wind-Mars interaction

    NASA Technical Reports Server (NTRS)

    Vaisberg, O. L.; Bogdanov, A. V.; Smirnov, V. N.; Romanov, S. A.

    1976-01-01

    Plasma measurements near Mars on the U.S.S.R. Mars-2, -3, and -5 spacecraft are considered. The data are compared with simultaneous magnetic measurements. Strong evidence is obtained in favor of a direct interaction and mass exchange between the solar wind plasma and the gaseous envelope of Mars.

  10. Speed Limits: Orientation and Semantic Context Interactions Constrain Natural Scene Discrimination Dynamics

    ERIC Educational Resources Information Center

    Rieger, Jochem W.; Kochy, Nick; Schalk, Franziska; Gruschow, Marcus; Heinze, Hans-Jochen

    2008-01-01

    The visual system rapidly extracts information about objects from the cluttered natural environment. In 5 experiments, the authors quantified the influence of orientation and semantics on the classification speed of objects in natural scenes, particularly with regard to object-context interactions. Natural scene photographs were presented in an…

  11. A Goal-Oriented Model of Natural Language Interaction

    DTIC Science & Technology

    1977-01-01

    AHSTKACT This report describes a research program in modeling human communication . The methodology involved selecting a single, naturally-occurring...knowledge is seldom used in the design process. Human communication skills have not bee’’ characferi?ed at a level of detail appropriate for guiding design...necessarily combine to give a complete picture of human communication . Experience over several more dialogues may suggest that one or all be replaced

  12. Effects of Human-Nature Interactions on Wildlife Habitat Dynamics: The Case of Wolong Nature Reserve for Giant Pandas

    NASA Astrophysics Data System (ADS)

    Vina, A.; Tuanmu, M.; Yang, W.; Liu, J.

    2012-12-01

    Human activities continue to induce the degradation of natural ecosystems, thus threatening not only the long-term survival of many wildlife species around the world, but also the resilience of natural ecosystems to global environmental changes. In response, many conservation efforts are emerging as adaptive strategies for coping with the degradation of natural ecosystems. Among them, the establishment of nature reserves is considered to be the most effective. However the effectiveness of nature reserves depends on the type and intensity of human activities occurring within their boundaries. But many of these activities constitute important livelihood systems for local human populations. Therefore, to enhance the effectiveness of conservation actions without significantly affecting local livelihood systems, it is essential to understand the complexity of human-nature interactions and their effects on the spatio-temporal dynamics of natural ecosystems. In this study, we evaluated the relation between giant panda habitat dynamics, conservation efforts and human activities in Wolong Nature Reserve for Giant Pandas, Sichuan Province, China. This reserve supports ca. 10% of the entire wild giant panda population but is also home to ca. 4,900 local residents. The spatio-temporal dynamics of giant panda habitat over the last four decades were analyzed using a time series of remotely sensed imagery acquired by different satellite sensor systems, including the Landsat Multi-Spectral Scanner, the Landsat Thematic Mapper and the Moderate Resolution Imaging Spectroradiometer (MODIS). Our assessment suggests that when local residents were actively involved in conservation efforts (through a payment for ecosystem services scheme established since around 2000) panda habitat started to recover, thus enhancing the resilience capacity of natural ecosystems in the Reserve. This reversed a long-term (> 30 years) trend of panda habitat degradation. The study not only has direct

  13. Rethinking equal access: agency, quality, and norms.

    PubMed

    Ruger, J P

    2007-01-01

    In 2005 the Global Health Council convened healthcare providers, community organizers, policymakers and researchers at Health Systems: Putting Pieces Together to discuss health from a systems perspective. Its report and others have established healthcare access and quality as two of the most important issues in health policy today. Still, there is little agreement about what equal access and quality mean for health system development. At the philosophical level, few have sought to understand why differences in healthcare quality are morally so troubling. While there has been considerable work in medical ethics on equal access, these efforts have neglected health agency (individuals' ability to work toward health goals they value) and health norms, both of which influence individuals' ability to be healthy. This paper argues for rethinking equal access in terms of an alternative ethical aim: to ensure the social conditions in which all individuals have the capability to be healthy. This perspective requires that we examine injustices not just by the level of healthcare resources, but by the: (1) quality of those resources and their capacity to enable effective health functioning; (2) extent to which society supports health agency so that individuals can convert healthcare resources into health functioning; and (3) nature of health norms, which affect individuals' efforts to achieve functioning.

  14. Natural cold baryogenesis from strongly interacting electroweak symmetry breaking

    SciTech Connect

    Konstandin, Thomas; Servant, Géraldine E-mail: geraldine.servant@cern.ch

    2011-07-01

    The mechanism of ''cold electroweak baryogenesis'' has been so far unpopular because its proposal has relied on the ad-hoc assumption of a period of hybrid inflation at the electroweak scale with the Higgs acting as the waterfall field. We argue here that cold baryogenesis can be naturally realized without the need to introduce any slow-roll potential. Our point is that composite Higgs models where electroweak symmetry breaking arises via a strongly first-order phase transition provide a well-motivated framework for cold baryogenesis. In this case, reheating proceeds by bubble collisions and we argue that this can induce changes in Chern-Simons number, which in the presence of new sources of CP violation commonly lead to baryogenesis. We illustrate this mechanism using as a source of CP violation an effective dimension-six operator which is free from EDM constraints, another advantage of cold baryogenesis compared to the standard theory of electroweak baryogenesis. Our results are general as they do not rely on any particular UV completion but only on a stage of supercooling ended by a first-order phase transition in the evolution of the universe, which can be natural if there is nearly conformal dynamics at the TeV scale. Besides, baryon-number violation originates from the Standard Model only.

  15. The complex nature of calcium cation interactions with phospholipid bilayers

    NASA Astrophysics Data System (ADS)

    Melcrová, Adéla; Pokorna, Sarka; Pullanchery, Saranya; Kohagen, Miriam; Jurkiewicz, Piotr; Hof, Martin; Jungwirth, Pavel; Cremer, Paul S.; Cwiklik, Lukasz

    2016-12-01

    Understanding interactions of calcium with lipid membranes at the molecular level is of great importance in light of their involvement in calcium signaling, association of proteins with cellular membranes, and membrane fusion. We quantify these interactions in detail by employing a combination of spectroscopic methods with atomistic molecular dynamics simulations. Namely, time-resolved fluorescent spectroscopy of lipid vesicles and vibrational sum frequency spectroscopy of lipid monolayers are used to characterize local binding sites of calcium in zwitterionic and anionic model lipid assemblies, while dynamic light scattering and zeta potential measurements are employed for macroscopic characterization of lipid vesicles in calcium-containing environments. To gain additional atomic-level information, the experiments are complemented by molecular simulations that utilize an accurate force field for calcium ions with scaled charges effectively accounting for electronic polarization effects. We demonstrate that lipid membranes have substantial calcium-binding capacity, with several types of binding sites present. Significantly, the binding mode depends on calcium concentration with important implications for calcium buffering, synaptic plasticity, and protein-membrane association.

  16. The complex nature of calcium cation interactions with phospholipid bilayers

    PubMed Central

    Melcrová, Adéla; Pokorna, Sarka; Pullanchery, Saranya; Kohagen, Miriam; Jurkiewicz, Piotr; Hof, Martin; Jungwirth, Pavel; Cremer, Paul S.; Cwiklik, Lukasz

    2016-01-01

    Understanding interactions of calcium with lipid membranes at the molecular level is of great importance in light of their involvement in calcium signaling, association of proteins with cellular membranes, and membrane fusion. We quantify these interactions in detail by employing a combination of spectroscopic methods with atomistic molecular dynamics simulations. Namely, time-resolved fluorescent spectroscopy of lipid vesicles and vibrational sum frequency spectroscopy of lipid monolayers are used to characterize local binding sites of calcium in zwitterionic and anionic model lipid assemblies, while dynamic light scattering and zeta potential measurements are employed for macroscopic characterization of lipid vesicles in calcium-containing environments. To gain additional atomic-level information, the experiments are complemented by molecular simulations that utilize an accurate force field for calcium ions with scaled charges effectively accounting for electronic polarization effects. We demonstrate that lipid membranes have substantial calcium-binding capacity, with several types of binding sites present. Significantly, the binding mode depends on calcium concentration with important implications for calcium buffering, synaptic plasticity, and protein-membrane association. PMID:27905555

  17. Simulation of Hydraulic and Natural Fracture Interaction Using a Coupled DFN-DEM Model

    SciTech Connect

    J. Zhou; H. Huang; M. Deo

    2016-03-01

    The presence of natural fractures will usually result in a complex fracture network due to the interactions between hydraulic and natural fracture. The reactivation of natural fractures can generally provide additional flow paths from formation to wellbore which play a crucial role in improving the hydrocarbon recovery in these ultra-low permeability reservoir. Thus, accurate description of the geometry of discrete fractures and bedding is highly desired for accurate flow and production predictions. Compared to conventional continuum models that implicitly represent the discrete feature, Discrete Fracture Network (DFN) models could realistically model the connectivity of discontinuities at both reservoir scale and well scale. In this work, a new hybrid numerical model that couples Discrete Fracture Network (DFN) and Dual-Lattice Discrete Element Method (DL-DEM) is proposed to investigate the interaction between hydraulic fracture and natural fractures. Based on the proposed model, the effects of natural fracture orientation, density and injection properties on hydraulic-natural fractures interaction are investigated.

  18. The nature of the metal-CO interaction and bonding

    NASA Technical Reports Server (NTRS)

    Bagus, P. S.; Nelin, C. J.; Bauschlicher, C. W., Jr.

    1984-01-01

    The adsorption of CO on metal surfaces is represented by molecular orbital cluster models of CO at an on top site and adsorbed normal to the surface carbon end down. Ab initio SCF and MCSCF calculations are performed for several clusters. The new constrained space orbital variation CSOV approach is used to analyze the bonding and to compare CO adsorption on Al, representative of sp metals, with that on Cu, representative of transition metals. There is a large repulsion between the superposed free CO and metal charge distributions which is considerably smaller for Cu than for Al because there are fewer valence sigma electrons for Cu than for Al. The CSOV analysis shows that the metal to CO pi donation is much more important than the CO to metal sigma donation. It is also shown that for Cu, the d pi contribution to the metal pi donation is larger than the valence 4p pi contribution. The d pi donation is compared between Fe, Ni, and Cu and this donation and the metal-CO interaction are found to be different in the order Fe greater than Ni greater than Cu.

  19. Rethinking Recycling in Arcs

    NASA Astrophysics Data System (ADS)

    Kelemen, P.; Behn, M. D.; Jagoutz, O.

    2012-12-01

    Hacker et al EPSL 2011 and Behn et al Nature Geosci 2011 investigated pathways for return of buoyant, subducted material to arc crust. These include (1) diapirs rising into the hot mantle wedge, with extensive melts adding a component to arc magmas, (2) flow of material back up a relatively cold "subduction channel", adding solids to the lower crust and small-degree partial melts to the upper crust, (3) flow from the forearc along the base of arc crust, and (4) imbrication of forearc material into arc crust. These processes add felsic, incompatible-element-rich components to arc crust. The flux of incompatible elements such as Th in arc lavas, thought to be mainly recycled from subducted sediments, is > sediment subduction flux. There are large uncertainties: arc crustal growth rates are imprecise; young, primitive arc lavas may not be representative of magmatic flux into arc crust; sediment subduction flux may have varied. Nevertheless, this result is found for all arcs examined, using recently published growth rates. Perhaps arc growth rates that include subduction erosion are systematically overestimated. Instead or in addition, maybe significant Th comes from material other than sediments. Here, we consider the implications of pathways 1-4 for arc growth rates and incompatible element enrichment, in the context of subduction erosion and arc-arc collision. Subducting arc lithologies can become separated, with only felsic components returned to arc crust. Buoyant lithologies are mobile in viscous instabilities at > 700-800°C. Whereas thin layers such as sediments may become mobile all at once, instabilities may periodically strip the hottest parts from the top of thick buoyant layers, replacing them with hot mantle. In arc-arc collision, the top of a subducting plate starts at about 0°C on the seafloor, so heating is slow. In subduction erosion, forearc material in the subducting package can be > 200°C before erosion so buoyant lithologies reach 700-800

  20. Rethinking biological activation of methane and conversion to liquid fuels.

    PubMed

    Haynes, Chad A; Gonzalez, Ramon

    2014-05-01

    If methane, the main component of natural gas, can be efficiently converted to liquid fuels, world reserves of methane could satisfy the demand for transportation fuels in addition to use in other sectors. However, the direct activation of strong C-H bonds in methane and conversion to desired products remains a difficult technological challenge. This perspective reveals an opportunity to rethink the logic of biological methane activation and conversion to liquid fuels. We formulate a vision for a new foundation for methane bioconversion and suggest paths to develop technologies for the production of liquid transportation fuels from methane at high carbon yield and high energy efficiency and with low CO2 emissions. These technologies could support natural gas bioconversion facilities with a low capital cost and at small scales, which in turn could monetize the use of natural gas resources that are frequently flared, vented or emitted.

  1. Nature of Interactions among Young Children and Adult Caregivers in a Children's Museum

    ERIC Educational Resources Information Center

    Dooley, Caitlin McMunn; Welch, Meghan M.

    2014-01-01

    This naturalistic, qualitative study examines the nature of child- and adult-led interactions in a children's museum. Using dialogic learning as a theoretical framework, the study examines how children and adults engage in interactions while learning at a museum. Findings suggest that children and adults are almost equally likely to lead…

  2. Using Script Fading to Promote Natural Environment Stimulus Control of Verbal Interactions among Youths with Autism

    ERIC Educational Resources Information Center

    Brown, John L.; Krantz, Patricia J.; McClannahan, Lynn E.; Poulson, Claire L.

    2008-01-01

    Script fading was used to teach three youths with autism to initiate and sustain verbal interactions under stimulus control consistent with the natural environment. The youths learned to engage in verbal interactions during simulated shopping trips and during visits to community stores. The effectiveness of script fading was examined using a…

  3. Psychological linguistics: A natural science approach to the study of language interactions

    PubMed Central

    Bijou, Sidney W.; Umbreit, John; Ghezzi, Patrick M.; Chao, Chia-Chen

    1986-01-01

    Kantor's theoretical analysis of “psychological linguistics” offers a natural science approach to the study of linguistic behavior and interactions. This paper includes brief descriptions of (a) some of the basic assumptions of the approach, (b) Kantor's conception of linguistic behavior and interactions, (c) a compatible research method and sample research data, and (d) some areas of research and application. PMID:22477507

  4. WordlePlus: Expanding Wordle's Use through Natural Interaction and Animation.

    PubMed

    Jo, Jaemin; Lee, Bongshin; Seo, Jinwook

    2015-01-01

    Wordle has been commonly used to summarize texts, with each word size-coded by its frequency of occurrences--the more often a word occurs in texts, the bigger it is. The interactive authoring tool WordlePlus leverages natural interaction and animation to give users more control over wordle development. WordlePlus supports direct manipulation of words with pen and touch interaction. It introduces two-word multitouch manipulation, such as concatenating and grouping two words, and provides pen interaction for adding and deleting words. In addition, WordlePlus employs animation to help users create more dynamic and engaging wordles.

  5. From nature versus nurture, via nature and nurture, to gene x environment interaction in mental disorders.

    PubMed

    Wermter, Anne-Kathrin; Laucht, Manfred; Schimmelmann, Benno G; Banaschewski, Tobias; Banaschweski, Tobias; Sonuga-Barke, Edmund J S; Rietschel, Marcella; Becker, Katja

    2010-03-01

    It is now generally accepted that complex mental disorders are the results of interplay between genetic and environmental factors. This holds out the prospect that by studying G x E interplay we can explain individual variation in vulnerability and resilience to environmental hazards in the development of mental disorders. Furthermore studying G x E findings may give insights in neurobiological mechanisms of psychiatric disorder and so improve individualized treatment and potentially prevention. In this paper, we provide an overview of the state of field with regard to G x E in mental disorders. Strategies for G x E research are introduced. G x E findings from selected mental disorders with onset in childhood or adolescence are reviewed [such as depressive disorders, attention-deficit/hyperactivity disorder (ADHD), obesity, schizophrenia and substance use disorders]. Early seminal studies provided evidence for G x E in the pathogenesis of depression implicating 5-HTTLPR, and conduct problems implicating MAOA. Since then G x E effects have been seen across a wide range of mental disorders (e.g., ADHD, anxiety, schizophrenia, substance abuse disorder) implicating a wide range of measured genes and measured environments (e.g., pre-, peri- and postnatal influences of both a physical and a social nature). To date few of these G x E effects have been sufficiently replicated. Indeed meta-analyses have raised doubts about the robustness of even the most well studied findings. In future we need larger, sufficiently powered studies that include a detailed and sophisticated characterization of both phenotype and the environmental risk.

  6. Long-range interactions and the sign of natural amplitudes in two-electron systems

    SciTech Connect

    Giesbertz, Klaas J. H.; Leeuwen, Robert van

    2013-09-14

    In singlet two-electron systems, the natural occupation numbers of the one-particle reduced density matrix are given as squares of the natural amplitudes which are defined as the expansion coefficients of the two-electron wave function in a natural orbital basis. In this work, we relate the sign of the natural amplitudes to the nature of the two-body interaction. We show that long-range Coulomb-type interactions are responsible for the appearance of positive amplitudes and give both analytical and numerical examples that illustrate how the long-distance structure of the wave function affects these amplitudes. We further demonstrate that the amplitudes show an avoided crossing behavior as function of a parameter in the Hamiltonian and use this feature to show that these amplitudes never become zero, except for special interactions in which infinitely many of them can become zero simultaneously when changing the interaction strength. This mechanism of avoided crossings provides an alternative argument for the non-vanishing of the natural occupation numbers in Coulomb systems.

  7. Natural history matters: how biological constraints shape diversified interactions in pollination networks.

    PubMed

    Jordano, Pedro

    2016-11-01

    Species-specific traits constrain the ways organisms interact in nature. Some pairwise interactions among coexisting species simply do not occur; they are impossible to observe despite the fact that partners coexist in the same place. The author discusses these 'forbidden links' of species interaction networks. Photo: a sphingid moth, Manduca sexta visiting a flower of Tocoyena formosa (Rubiaceae) in the Brazilian Cerrado; tongue and corolla tube lengths approximately 100 mm. Courtesy of Felipe Amorim. Sazatornil, F.D., Moré, M., Benitez-Vieyra, S., Cocucci, A.A., Kitching, I.J., Schlumpberger, B.O., Oliveira, P.E., Sazima, M. & Amorim, F.W. (2016) Beyond neutral and forbidden links: morphological matches and the assembly of mutualistic hawkmoth-plant networks. Journal of Animal Ecology, 85, 1586-1594. Species-specific traits and life-history characteristics constrain the ways organisms interact in nature. For example, gape-limited predators are constrained in the sizes of prey they can handle and efficiently consume. When we consider the ubiquity of such constrains, it is evident how hard it can be to be a generalist partner in ecological interactions: a free-living animal or plant cannot simply interact with every available partner it encounters. Some pairwise interactions among coexisting species simply do not occur; they are impossible to observe despite the fact that partners coexist in the same place. Sazatornil et al. () explore the nature of such constraints in the mutualisms among hawkmoths and the plants they pollinate. In this iconic interaction, used by Darwin and Wallace to vividly illustrate the power of natural selection in shaping evolutionary change, both pollinators and plants are sharply constrained in their interaction modes and outcomes.

  8. Macro and micro scale interactions between cohesive sediment tracers and natural mud.

    NASA Astrophysics Data System (ADS)

    Spencer, Kate; Manning, Andrew; Droppo, Ian; Leppard, Gary; Benson, Thomas

    2010-05-01

    Understanding the dispersion patterns of fine, cohesive sediment (< 63 micron) is fundamental to the sustainable management of aquatic environments. In order to develop sediment transport models and predict sediment dispersion, accurate field techniques for the measurement of sediment transport are required. Although this is relatively simple for the sand sized fraction, measuring transport pathways for cohesive sediment is more problematic. Cohesive sediment tracers developed for this purpose include synthetic tracer particles (e.g. polymers) and labelled natural clays (e.g. Mahler et al. 1998, Yin et al. 1999, Krezoski 1985; Spencer et al. 2007) and a fundamental assumption is that the tracer has the same physical properties as natural sediment. For the cohesive fraction this means that the tracer must be incorporated into and transported via floc aggregates (Black et al. 2006). A few studies have examined the physical behaviour of cohesive tracers (e.g. Manning et al. in press) but most are limited to the examination of gross settling characteristics (e.g. Louisse et al. 1986) rather than floc formation and behaviour. This work focuses on a labelled natural clay; a Ho-montmorillonite (see Spencer et al. 2007). The aims of this work were to examine the physical characteristics, internal structure and settling dynamics of the tracer and to determine whether the tracer flocculated and interacted with natural estuarine muds at both macro- and microscales. To our knowledge, this is the first study to present data examining the flocculation characteristics and structure of cohesive sediment tracers and their interaction with natural sediment. Macroscale floc characteristics such as floc size and settling velocity measurements were obtained using the LabSFLOC - Laboratory Spectral Flocculation Characteristics - instrument. Floc density, porosity, dry mass, and mass settling flux were then calculated. Floc internal microstructure (1-2 nm) and elemental floc composition

  9. Rethinking reproductive "tourism" as reproductive "exile".

    PubMed

    Inhorn, Marcia C; Patrizio, Pasquale

    2009-09-01

    Whereas reproductive "tourism" implies leisure travel, reproductive "exile" bespeaks the numerous difficulties and constraints faced by infertile patients who are "forced" to travel globally for assisted reproduction. Given this reality, it is time to rethink the language of "reproductive tourism," replacing it with more accurate and patient-centered terms.

  10. Rethinking the Use of Teaching Resources.

    ERIC Educational Resources Information Center

    Miles, Karen Hawley

    1997-01-01

    Rethinks the use of teachers, a school's most expensive and important resource. Four categories could benefit from restructuring: teacher and aide allocation/assignment, teacher compensation, student support services, and general and special program administration. Middletown, New York, actually improved its student:teacher ratio by using its…

  11. Pest control of aphids depends on landscape complexity and natural enemy interactions

    PubMed Central

    Reineking, Björn; Seo, Bumsuk; Steffan-Dewenter, Ingolf

    2015-01-01

    Aphids are a major concern in agricultural crops worldwide, and control by natural enemies is an essential component of the ecological intensification of agriculture. Although the complexity of agricultural landscapes is known to influence natural enemies of pests, few studies have measured the degree of pest control by different enemy guilds across gradients in landscape complexity. Here, we use multiple natural-enemy exclosures replicated in 18 fields across a gradient in landscape complexity to investigate (1) the strength of natural pest control across landscapes, measured as the difference between pest pressure in the presence and in the absence of natural enemies; (2) the differential contributions of natural enemy guilds to pest control, and the nature of their interactions across landscapes. We show that natural pest control of aphids increased up to six-fold from simple to complex landscapes. In the absence of pest control, aphid population growth was higher in complex than simple landscapes, but was reduced by natural enemies to similar growth rates across all landscapes. The effects of enemy guilds were landscape-dependent. Particularly in complex landscapes, total pest control was supplied by the combined contribution of flying insects and ground-dwellers. Birds had little overall impact on aphid control. Despite evidence for intraguild predation of flying insects by ground-dwellers and birds, the overall effect of enemy guilds on aphid control was complementary. Understanding pest control services at large spatial scales is critical to increase the success of ecological intensification schemes. Our results suggest that, where aphids are the main pest of concern, interactions between natural enemies are largely complementary and lead to a strongly positive effect of landscape complexity on pest control. Increasing the availability of seminatural habitats in agricultural landscapes may thus benefit not only natural enemies, but also the effectiveness of

  12. Pest control of aphids depends on landscape complexity and natural enemy interactions.

    PubMed

    Martin, Emily A; Reineking, Björn; Seo, Bumsuk; Steffan-Dewenter, Ingolf

    2015-01-01

    Aphids are a major concern in agricultural crops worldwide, and control by natural enemies is an essential component of the ecological intensification of agriculture. Although the complexity of agricultural landscapes is known to influence natural enemies of pests, few studies have measured the degree of pest control by different enemy guilds across gradients in landscape complexity. Here, we use multiple natural-enemy exclosures replicated in 18 fields across a gradient in landscape complexity to investigate (1) the strength of natural pest control across landscapes, measured as the difference between pest pressure in the presence and in the absence of natural enemies; (2) the differential contributions of natural enemy guilds to pest control, and the nature of their interactions across landscapes. We show that natural pest control of aphids increased up to six-fold from simple to complex landscapes. In the absence of pest control, aphid population growth was higher in complex than simple landscapes, but was reduced by natural enemies to similar growth rates across all landscapes. The effects of enemy guilds were landscape-dependent. Particularly in complex landscapes, total pest control was supplied by the combined contribution of flying insects and ground-dwellers. Birds had little overall impact on aphid control. Despite evidence for intraguild predation of flying insects by ground-dwellers and birds, the overall effect of enemy guilds on aphid control was complementary. Understanding pest control services at large spatial scales is critical to increase the success of ecological intensification schemes. Our results suggest that, where aphids are the main pest of concern, interactions between natural enemies are largely complementary and lead to a strongly positive effect of landscape complexity on pest control. Increasing the availability of seminatural habitats in agricultural landscapes may thus benefit not only natural enemies, but also the effectiveness of

  13. Nature and nurture: A step towards investigating their interactions in the wild.

    PubMed

    Fríre, Celine H; Mann, Janet; Krützen, Michael; Connor, Richard C; Bejder, Lars; Sherwin, William B

    2011-03-01

    The debate about the relative importance of nature versus nurture has been around for decades, but despite this, there has been very little evidence about how these might in fact interact to drive evolution in the wild. Recently, the identification of a comparable methodology for analyzing both genetic and social effects of phenotypic variation revealed that fitness variation in a free-living population of dolphin was driven by a strong social and genetic interaction. This study not only provides evidence that nature and nurture do interact to drive phenotypic evolution but also represents a step towards partitioning the effects of genetic, social, environmental factors and their multiway interactions to better understand phenotypic evolution in the wild.

  14. Nature of Short Li...H-C Contact Interactions in Organolithium Compounds and Its Implication

    DTIC Science & Technology

    1992-05-15

    4.W I IT DATI A3.3T P A M M W 9 05-15-92 Technical 06-01-91 to 05-;31-92 4. lI AND SUBITTLE 5.pgoj5uua Nature of Short Li ... -C Contact Interactions...strongly stabilizing, and the associated interaction energy is nearly half the inding energy of an isolated LiH. This finding provides a natural...clusters leads to a large number of strongly stabilizing intermolecular Li ... H-C contacts involving the Li- baring carbon atoms. The present work

  15. Study on interaction between induced and natural fractures by extended finite element method

    NASA Astrophysics Data System (ADS)

    Xu, DanDan; Liu, ZhanLi; Zhuang, Zhuo; Zeng, QingLei; Wang, Tao

    2017-02-01

    Fracking is one of the kernel technologies in the remarkable shale gas revolution. The extended finite element method is used in this paper to numerically investigate the interaction between hydraulic and natural fractures, which is an important issue of the enigmatic fracture network formation in fracking. The criteria which control the opening of natural fracture and crossing of hydraulic fracture are tentatively presented. Influence factors on the interaction process are systematically analyzed, which include the approach angle, anisotropy of in-situ stress and fluid pressure profile.

  16. Exploring the Interaction Natures in Plutonyl (VI) Complexes with Topological Analyses of Electron Density.

    PubMed

    Du, Jiguang; Sun, Xiyuan; Jiang, Gang

    2016-04-11

    The interaction natures between Pu and different ligands in several plutonyl (VI) complexes are investigated by performing topological analyses of electron density. The geometrical structures in both gaseous and aqueous phases are obtained with B3LYP functional, and are generally in agreement with available theoretical and experimental results when combined with all-electron segmented all-electron relativistic contracted (SARC) basis set. The Pu- O y l bond orders show significant linear dependence on bond length and the charge of oxygen atoms in plutonyl moiety. The closed-shell interactions were identified for Pu-Ligand bonds in most complexes with quantum theory of atoms in molecules (QTAIM) analyses. Meanwhile, we found that some Pu-Ligand bonds, like Pu-OH(-), show weak covalent. The interactive nature of Pu-ligand bonds were revealed based on the interaction quantum atom (IQA) energy decomposition approach, and our results indicate that all Pu-Ligand interactions is dominated by the electrostatic attraction interaction as expected. Meanwhile it is also important to note that the quantum mechanical exchange-correlation contributions can not be ignored. By means of the non-covalent interaction (NCI) approach it has been found that some weak and repulsion interactions existed in plutonyl(VI) complexes, which can not be distinguished by QTAIM, can be successfully identified.

  17. Exploring the Interaction Natures in Plutonyl (VI) Complexes with Topological Analyses of Electron Density

    PubMed Central

    Du, Jiguang; Sun, Xiyuan; Jiang, Gang

    2016-01-01

    The interaction natures between Pu and different ligands in several plutonyl (VI) complexes are investigated by performing topological analyses of electron density. The geometrical structures in both gaseous and aqueous phases are obtained with B3LYP functional, and are generally in agreement with available theoretical and experimental results when combined with all-electron segmented all-electron relativistic contracted (SARC) basis set. The Pu–Oyl bond orders show significant linear dependence on bond length and the charge of oxygen atoms in plutonyl moiety. The closed-shell interactions were identified for Pu-Ligand bonds in most complexes with quantum theory of atoms in molecules (QTAIM) analyses. Meanwhile, we found that some Pu–Ligand bonds, like Pu–OH−, show weak covalent. The interactive nature of Pu–ligand bonds were revealed based on the interaction quantum atom (IQA) energy decomposition approach, and our results indicate that all Pu–Ligand interactions is dominated by the electrostatic attraction interaction as expected. Meanwhile it is also important to note that the quantum mechanical exchange-correlation contributions can not be ignored. By means of the non-covalent interaction (NCI) approach it has been found that some weak and repulsion interactions existed in plutonyl(VI) complexes, which can not be distinguished by QTAIM, can be successfully identified. PMID:27077844

  18. Interactions between toxic chemicals and natural environmental factors--a meta-analysis and case studies.

    PubMed

    Laskowski, Ryszard; Bednarska, Agnieszka J; Kramarz, Paulina E; Loureiro, Susana; Scheil, Volker; Kudłek, Joanna; Holmstrup, Martin

    2010-08-15

    The paper addresses problems arising from effects of natural environmental factors on toxicity of pollutants to organisms. Most studies on interactions between toxicants and natural factors, including those completed in the EU project NoMiracle (Novel Methods for Integrated Risk Assessment of Cumulative Stressors in Europe) described herein, showed that effects of toxic chemicals on organisms can differ vastly depending purely on external conditions. We compiled data from 61 studies on effects of temperature, moisture and dissolved oxygen on toxicity of a range of chemicals representing pesticides, polycyclic aromatic hydrocarbons, plant protection products of bacterial origin and trace metals. In 62.3% cases significant interactions (p< or =0.05 or less) between natural factors and chemicals were found, reaching 100% for the effect of dissolved oxygen on toxicity of waterborne chemicals. The meta-analysis of the 61 studies showed that the null hypothesis assuming no interactions between toxic chemicals and natural environmental factors should be rejected at p=2.7 x 10(-82) (truncated product method probability). In a few cases of more complex experimental designs, also second-order interactions were found, indicating that natural factors can modify interactions among chemicals. Such data emphasize the necessity of including information on natural factors and their variation in time and across geographic regions in ecological risk assessment. This can be done only if appropriate ecotoxicological test designs are used, in which test organisms are exposed to toxicants at a range of environmental conditions. We advocate designing such tests for the second-tier ecological risk assessment procedures.

  19. Quenching interaction of BSA with DTAB is dynamic in nature: A spectroscopic insight

    NASA Astrophysics Data System (ADS)

    Das, Nirmal Kumar; Pawar, Lavanya; Kumar, Naveen; Mukherjee, Saptarshi

    2015-08-01

    The role of electrostatic interactions between the protein, Bovine Serum Albumin (BSA) and the cationic surfactant, dodecyltrimethylammonium bromide (DTAB) has been substantiated using spectroscopic approaches. The primary mechanism of fluorescence quenching of the tryptophan of BSA is most probably dynamic in nature as the complex formation resulting in a protein-surfactant assembly is not very spontaneous. The weak interaction buries the tryptophan amino acid residue inside the protein scaffolds which have been quantitatively proved by our acrylamide quenching studies. The loss in the secondary structure of the protein as a result of interaction with DTAB has been elucidated by CD spectroscopy.

  20. Interaction of diamidino-2-phenylindole (DAPI) with natural and synthetic nucleic acids.

    PubMed Central

    Manzini, G; Barcellona, M L; Avitabile, M; Quadrifoglio, F

    1983-01-01

    The interaction of DAPI with natural and synthetic polydeoxynucleotides of different base content and sequences was studied with circular dichroism, ultracentrifugation, viscosity and calorimetry. All the polymers show two types of binding. The strength of the interaction and its resistance to ionic strength are related to the content of AT clusters in the chain. On the other hand, sedimentation measurements rule out an intercalation mechanism. A model of DAPI interaction with DNA, similar to that displayed by distamycin and netropsin, is proposed. PMID:6672773

  1. Communication Interaction between Aided and Natural Speakers: A State of the Art Report.

    ERIC Educational Resources Information Center

    Kraat, Arlene W.

    The report integrates findings of an international state-of-the-art study of augmentative communication, focusing on the interaction between a person using a communication aid and an able-bodied, natural speaker. Chapter titles and selected subtopics are as follows: (1) "Beyond Symbols and Switches: The Study of Communication Aid Use";…

  2. Discrimination of Coronal Stops by Bilingual Adults: The Timing and Nature of Language Interaction

    ERIC Educational Resources Information Center

    Sundara, Megha; Polka, Linda

    2008-01-01

    The current study was designed to investigate the timing and nature of interaction between the two languages of bilinguals. For this purpose, we compared discrimination of Canadian French and Canadian English coronal stops by simultaneous bilingual, monolingual and advanced early L2 learners of French and English. French /d/ is phonetically…

  3. Utilizing Teaching Interactions to Facilitate Social Skills in the Natural Environment

    ERIC Educational Resources Information Center

    Kassardjian, Alyne; Taubman, Mitchell; Rudrud, Eric; Leaf, Justin B.; Edwards, Andrew; McEachin, John; Leaf, Ron; Schulze, Kim

    2013-01-01

    Individuals diagnosed with autism spectrum disorder often display deficits in social skills. While research has shown behavioral interventions to be effective in teaching and/or increasing a variety of appropriate social skills, limited research has shown generalization of these skills to the natural setting. The Teaching Interaction procedure…

  4. Language and Interactional Discourse: Deconstrusting the Talk-Generating Machinery in Natural Conversation

    ERIC Educational Resources Information Center

    Enyi, Amaechi Uneke

    2015-01-01

    The study entitled "Language and Interactional Discourse: Deconstructing the Talk-Generating Machinery in Natural Conversation" is an analysis of spontaneous and informal conversation. The study, carried out in the theoretical and methodological tradition of Ethnomethodology, was aimed at explicating how ordinary talk is organized and…

  5. A mass assembly of associative mechanisms: a dynamical systems account of natural social interaction.

    PubMed

    Duran, Nicholas D; Dale, Rick; Richardson, Daniel C

    2014-04-01

    The target article offers a negative, eliminativist thesis, dissolving the specialness of mirroring processes into a solution of associative mechanisms. We support the authors' project enthusiastically. What they are currently missing, we argue, is a positive, generative thesis about associative learning mechanisms and how they might give way to the complex, multimodal coordination that naturally arises in social interaction.

  6. Introduction to Special Issue: Understanding the Nature-Nurture Interactions in Language and Learning Differences.

    ERIC Educational Resources Information Center

    Berninger, Virginia Wise

    2001-01-01

    The introduction to this special issue on nature-nurture interactions notes that the following articles represent five biologically oriented research approaches which each provide a tutorial on the investigator's major research tool, a summary of current research understandings regarding language and learning differences, and a discussion of…

  7. Interpreters' Involvement in Multi-Party Interactions: The Nature of Participation as Listener and Speaker

    ERIC Educational Resources Information Center

    Takimoto, Masato

    2012-01-01

    This paper investigates two naturally occurring business interpreting situations where there are a number of participants. Unlike dialogue interpreting situations where there are only two primary interlocutors, the overall interaction shows more complexity in these multi-party situations. This, in turn, means that the interpreters' functions and…

  8. Multimodal interactions in typically and atypically developing children: natural versus artificial environments.

    PubMed

    Giannopulu, Irini

    2013-11-01

    This review addresses the central role played by multimodal interactions in neurocognitive development. We first analyzed our studies of multimodal verbal and nonverbal cognition and emotional interactions within neuronal, that is, natural environments in typically developing children. We then tried to relate them to the topic of creating artificial environments using mobile toy robots to neurorehabilitate severely autistic children. By doing so, both neural/natural and artificial environments are considered as the basis of neuronal organization and reorganization. The common thread underlying the thinking behind this approach revolves around the brain's intrinsic properties: neuroplasticity and the fact that the brain is neurodynamic. In our approach, neural organization and reorganization using natural or artificial environments aspires to bring computational perspectives into cognitive developmental neuroscience.

  9. Discrimination of coronal stops by bilingual adults: the timing and nature of language interaction.

    PubMed

    Sundara, Megha; Polka, Linda

    2008-01-01

    The current study was designed to investigate the timing and nature of interaction between the two languages of bilinguals. For this purpose, we compared discrimination of Canadian French and Canadian English coronal stops by simultaneous bilingual, monolingual and advanced early L2 learners of French and English. French /d/ is phonetically described as dental whereas English /d/ is described as alveolar. Using a categorial AXB task, the performance of all four groups was compared to chance and to the performance of native Hindi listeners. Hindi listeners performed well above chance in discriminating French and English /d/-initial syllables. The discrimination performance of advanced early L2 learners, but not simultaneous bilinguals, was consistent with one merged category for coronal stops in the two languages. The data provide evidence for interaction in L2 learners as well as simultaneous bilinguals; however, the nature of the interaction is different in the two groups.

  10. Four basic levels of the interactions between humanity and the imbalanced Nature

    NASA Astrophysics Data System (ADS)

    Kontar, V. A.

    2013-12-01

    There are the clearly distinguishable four basic levels of interaction the humanity with the imbalanced Nature: 1 Level - Naivety: Self-healing Nature in defiance of the humanity activities. 2 Level - Collaboration: Restoration of Nature in cooperation with humanity. 3 Level - Conflict: The resistance of Nature against the humanity's interference. 4 Level - Disappearance: Nature destroys humanity as the trouble maker. On the first level the people were afraid and respected Nature and are taking from Nature only what Nature gave willingly. Therefore Nature could easy regenerate itself. So it was thousands of years and people become under the false impression that it will be forever. The first signs the end of this period was visible in the era of industrialization. It turned out that resources are not infinite, and the waste of humanity grows much faster than Nature can utilize or dispose it. But in the world still had plenty of the untouched places and industrialization continued to develop rapidly. Thus problems with Nature were dislocated into the colonies rather far off from the prosperous metropolitan countries. The false impression about the man's victory over Nature has increased. Very soon the main untouched place was used, and the global circulations bring the pollutions from colonies to the metropolis. The second level was started as processes to creating the national parks, natural reservations, etc. It was some beginning of the cooperation humanity with Nature. The invasion into the Nature of the colonies was intensified. In addition start increasing the pollution in the metropolis from the waste of resources which have been imported from the colonies. The third level was started and Nature began to resist and revenge to the self-confident man. But man didn't stop and continued create more and more aggressive processes which provoked some avalanches-looks reactions of Nature. Now people can start these avalanches, but cannot stop it. One of these man

  11. Pregnane X receptor and natural products: beyond drug-drug interactions.

    PubMed

    Staudinger, Jeff L; Ding, Xunshan; Lichti, Kristin

    2006-12-01

    The pregnane X receptor (PXR, NR1I2) is a member of the nuclear receptor superfamily that is activated by a myriad of compounds and natural products in clinical use. Activation of PXR represents the basis for several clinically important drug-drug interactions. Although PXR activation has undesirable effects in patients on combination therapy, it also mediates the hepatoprotective effects exhibited by some herbal remedies. This review focuses on PXR activation by natural products and the potential therapeutic opportunities presented. In particular, the biological effects of St. John's Wort, gugulipid, kava kava, Coleus forskolii, Hypoxis, Sutherlandia, qing hao, wu wei zi, gan cao and other natural products are discussed. The impact of these natural products on drug metabolism and hepatoprotection is highlighted in the context of activation and antagonism of PXR.

  12. Pregnane X receptor and natural products: beyond drug–drug interactions

    PubMed Central

    Staudinger, Jeff L; Ding, Xunshan; Lichti, Kristin

    2010-01-01

    The pregnane X receptor (PXR, NR1I2) is a member of the nuclear receptor superfamily that is activated by a myriad of compounds and natural products in clinical use. Activation of PXR represents the basis for several clinically important drug–drug interactions. Although PXR activation has undesirable effects in patients on combination therapy, it also mediates the hepatoprotective effects exhibited by some herbal remedies. This review focuses on PXR activation by natural products and the potential therapeutic opportunities presented. In particular, the biological effects of St. John’s Wort, gugulipid, kava kava, Coleus forskolii, Hypoxis, Sutherlandia, qing hao, wu wei zi, gan cao and other natural products are discussed. The impact of these natural products on drug metabolism and hepatoprotection is highlighted in the context of activation and antagonism of PXR. PMID:17125405

  13. Interaction of plant pigment brazilin with synthetic and natural DNA: spectroscopic and in silico perspective.

    PubMed

    Bhakta, Dipita; Lulu, Sajitha; Jayaraman, G; Babu, S; Siva, Ramamoorthy

    2013-03-01

    The interactions between the molecules and DNA shape up an avenue for DNA targeted therapeutics. For the first time, brazilin, a major component of Caesalpinia sappan L., has been investigated for its interaction with natural and synthetic DNA. Detailed analyses of the binding property of brazilin dye with DNA by UV-vis, FTIR and Circular Dichroism were carried out. In addition, in silico studies have been conducted via tools of energy minimization and ligand optimization using Yasara and Argus Lab softwares along with the molecular docking server integrating Auto Dock, Mavin and Mopac. Results show that brazilin dye has commendable proficiency in being moulded as a binder with DNA. The specificity of the dye to stain nuclei in tissue sections positively indicates its interaction with nucleic acid. As the intracellular target for the majority of anticancer and antibiotic drugs is DNA, the study on the interaction between molecules like brazilin and DNA has great significance and implications in several biological applications.

  14. The stress-coping (mis)match hypothesis for nature × nurture interactions.

    PubMed

    Homberg, Judith R

    2012-01-13

    There is high consensus that stress-related disorders like depression are shaped by nature×nurture interactions. However, the complexity appears larger than envisaged and nature×nurture research is progressing too slowly. An important reason is that mainstream research is focussing on the idea that a combination of genotypic stress-sensitivity and stress exposure inevitably leads to maladaptive stress-coping responses, and thereby stress-related disorders. However, stress-coping responses can also be adaptive and adhere to the expected norm. Here I elaborate the 'environment' mismatch hypothesis proposed by Mathias Schmidt (Psychoneuroendocrinology, 36, 330-338, 2011) to the stress-coping (mis)match (SCM) hypothesis postulating that stress-coping responses-as programmed by nature×age-dependent nurture interactions-are adaptive when they match current stress conditions, but maladaptive when they mismatch current stress conditions. For instance, acquisition of an active stress-coping response during nurture may lead to the programmed release of active coping responses in current life. This is adaptive when current stress is escapable, but maladaptive when current stress is inescapable, leading to agitation. A model par example for nature×nurture interactions is the serotonin transporter promoter polymorphism, which will be discussed in the framework of the SCM hypothesis. The potential role of the prefrontal-amygdala circuit and the therapeutic implications of the SCM hypothesis will also be discussed.

  15. The nature of the interaction of dimethylselenide with IIIA group element compounds.

    PubMed

    Madzhidov, Timur I; Chmutova, Galina A

    2013-05-16

    The first systematic theoretical study of the nature of intermolecular bonding of dimethylselenide as donor and IIIA group element halides as acceptors was made with the help of the approach of Quantum Theory of Atoms in Molecules. Density Functional Theory with "old" Sapporo triple-ζ basis sets was used to calculate geometry, thermodynamics, and wave function of Me2Se···AX3 complexes. The analysis of the electron density distribution and the Laplacian of the electron density allowed us to reveal and explain the tendencies in the influence of the central atom (A = B, Al, Ga, In) and halogen (X = F, Cl, Br, I) on the nature of Se···A bonding. Significant changes in properties of the selenium lone pair upon complexation were described by means of the analysis of the Laplacian of the charge density. Charge transfer characteristics and the contributions to it from electron localization and delocalization were analyzed in terms of localization and delocalization indexes. Common features of the complexation and differences in the nature of bonding were revealed. Performed analysis evidenced that gallium and indium halide complexes can be attributed to charge transfer-driven complexes; aluminum halides complexes seem to be mainly of an electrostatic nature. The nature of bonding in different boron halides essentially varies; these complexes are stabilized mainly by covalent Se···B interaction. In all the complexes under study covalence of the Se···A interaction is rather high.

  16. Application of isothermal titration calorimetry as a tool to study natural product interactions.

    PubMed

    Callies, O; Hernández Daranas, A

    2016-07-28

    Covering: up to February 2015Over the past twenty-five years, isothermal titration calorimetry (ITC) has become a potent tool for the study a great variety of molecular interactions. This technique is able to provide a complete thermodynamic profile of an interaction process in a single experiment, with a series of advantages in comparison to other comparable techniques, such as less amount of sample or no need of chemical modification or labelling. It is thus not surprising that ITC has been applied to study the manifold types of interactions of natural products to get new insights into the molecular key factors implied in the complexation process of this type of compounds. This review provides an overview over the applications of ITC as a potent tool to investigate interactions of natural products with proteins, nucleic acids, oligosaccharides, and other types of receptors. The examples have been selected depending on the impact that this technique had during the investigation and revision of the interactions involved in the bioactivity of a compound, lead optimization or technical applications.

  17. The nature of social preference and interactions in Smith-Magenis syndrome.

    PubMed

    Wilde, Lucy; Silva, Daniel; Oliver, Chris

    2013-12-01

    This natural observation study was designed to evaluate hypothesized elevated 'attention-seeking' and preference for adult attention in Smith-Magenis syndrome. Ten children with Smith-Magenis syndrome were observed across one school day, together with an age matched sample of 10 children with Down syndrome. Levels of attention given to, and vigilance for, adults and peers were recorded and compared. Sequences of behaviour were analyzed to evaluate the temporal relationships between giving and receiving attention during adult-child interactions. Compared to children with Down syndrome, children with Smith-Magenis syndrome gave preferential attention to adults and looked towards adults significantly more than they looked towards peers. Sequential analyses revealed that while children with Smith-Magenis syndrome did not initiate interactions with adults more than children with Down syndrome did, reciprocity between child and adult social behaviours in Smith-Magenis syndrome within interactions was compromised. This less synchronous sequence of child and adult interactions in Smith-Magenis syndrome may be the result of children with Smith-Magenis syndrome attempting to initiate interaction at times when it is unavailable. The marked preference for interacting with adults over peers in Smith-Magenis syndrome indicates atypicality of social interaction in this syndrome.

  18. The Tri-Trophic Interactions Hypothesis: Interactive Effects of Host Plant Quality, Diet Breadth and Natural Enemies on Herbivores

    PubMed Central

    Mooney, Kailen A.; Pratt, Riley T.; Singer, Michael S.

    2012-01-01

    Several influential hypotheses in plant-herbivore and herbivore-predator interactions consider the interactive effects of plant quality, herbivore diet breadth, and predation on herbivore performance. Yet individually and collectively, these hypotheses fail to address the simultaneous influence of all three factors. Here we review existing hypotheses, and propose the tri-trophic interactions (TTI) hypothesis to consolidate and integrate their predictions. The TTI hypothesis predicts that dietary specialist herbivores (as compared to generalists) should escape predators and be competitively dominant due to faster growth rates, and that such differences should be greater on low quality (as compared to high quality) host plants. To provide a preliminary test of these predictions, we conducted an empirical study comparing the effects of plant (Baccharis salicifolia) quality and predators between a specialist (Uroleucon macolai) and a generalist (Aphis gossypii) aphid herbivore. Consistent with predictions, these three factors interactively determine herbivore performance in ways not addressed by existing hypotheses. Compared to the specialist, the generalist was less fecund, competitively inferior, and more sensitive to low plant quality. Correspondingly, predator effects were contingent upon plant quality only for the generalist. Contrary to predictions, predator effects were weaker for the generalist and on low-quality plants, likely due to density-dependent benefits provided to the generalist by mutualist ants. Because the TTI hypothesis predicts the superior performance of specialists, mutualist ants may be critical to A. gossypii persistence under competition from U. macolai. In summary, the integrative nature of the TTI hypothesis offers novel insight into the determinants of plant-herbivore and herbivore-predator interactions and the coexistence of specialist and generalist herbivores. PMID:22509298

  19. Interacting with Nature Improves Cognition and Affect for Individuals with Depression

    PubMed Central

    Berman, Marc G.; Kross, Ethan; Krpan, Katherine M.; Askren, Mary K.; Burson, Aleah; Deldin, Patricia J.; Kaplan, Stephen; Sherdell, Lindsey; Gotlib, Ian H.; Jonides, John

    2012-01-01

    Background This study aimed to explore whether walking in nature may be beneficial for individuals with major depressive disorder (MDD). Healthy adults demonstrate significant cognitive gains after nature walks, but it was unclear whether those same benefits would be achieved in a depressed sample as walking alone in nature might induce rumination, thereby worsening memory and mood. Methods Twenty individuals diagnosed with MDD participated in this study. At baseline, mood and short term memory span were assessed using the PANAS and the backwards digit span (BDS) task, respectively. Participants were then asked to think about an unresolved negative autobiographical event to prime rumination, prior to taking a 50 minute walk in either a natural or urban setting. After the walk, mood and short-term memory span were reassessed. The following week, participants returned to the lab and repeated the entire procedure, but walked in the location not visited in the first session (i.e., a counterbalanced within-subjects design). Results Participants exhibited significant increases in memory span after the nature walk relative to the urban walk, p < .001, ηp2= .53 (a large effect-size). Participants also showed increases in mood, but the mood effects did not correlate with the memory effects, suggesting separable mechanisms and replicating previous work. Limitations Sample size and participants’ motivation. Conclusions These findings extend earlier work demonstrating the cognitive and affective benefits of interacting with nature to individuals with MDD. Therefore, interacting with nature may be useful clinically as a supplement to existing treatments for MDD. PMID:22464936

  20. Nature of chalcogen hor ellipsis chalcogen contact interactions in organic donor-molecule salts

    SciTech Connect

    Novoa, J.J.; Whangbo, Myung-Hwan . Dept. of Chemistry); Williams, J.M. )

    1990-01-01

    The nature of chalcogen{hor ellipsis}chalcogen contact interactions in organic donor-molecule salts was examined by performing ab initio SCF-MO/MP2 calculations on H{sub 2}X{hor ellipsis}XH{sub 2}(X = O, S, SE, Te) and MM2 calculations on donor dimers (TXF){sub 2} (X = S, SE, Te) and (BEDX-TTF){sub 2} (X = O, S). 14 refs., 4 figs., 4 tabs.

  1. Interactions between Oil-Spill Pollutants and Natural Stressors Can Compound Ecotoxicological Effects

    PubMed Central

    Whitehead, Andrew

    2013-01-01

    Coastal estuaries are among the most biologically productive habitats on earth, yet are at risk from human activities including marine oil spills. The 2010 Deepwater Horizon oil spill contaminated hundreds of kilometers of coastal habitat, particularly in Louisiana's delta. Coastal estuaries are naturally dynamic habitats where periodic and stochastic fluctuations, for example in temperature, salinity, nutrients, and hypoxia, are common. Such environmental variability regularly imposes suboptimal conditions for which resident species must continually compensate by drawing on diverse physiological abilities. However, exposures to oil, in addition to their direct toxic effects, may interfere with functions that normally enable physiological compensation for suboptimal conditions. This review summarizes the panoply of naturally-encountered stressors that may interact with oil, including salinity, hypoxia, pathogens, and competition, and the mechanisms that may underlie these interactions. Combined effects of these stressors can amplify the costs of oil-exposures to organisms in the real world, and contribute to impacts on fitness, populations, and communities, that may not have been predicted from direct toxicity of hydrocarbons alone. These interactions pose challenges for accurate and realistic assessment of risks and of actual damage. To meet these challenges, environmental scientists and managers must capitalize on the latest understanding of the complexities of chemical effects of natural stressors on organisms, and adopt integrative and holistic measures of effect from the molecular to whole-animal levels, in order to anticipate, characterize, diagnose, and solve, ecotoxicological problems. PMID:23842611

  2. Evolutionary Influenced Interaction Pattern as Indicator for the Investigation of Natural Variants Causing Nephrogenic Diabetes Insipidus.

    PubMed

    Grunert, Steffen; Labudde, Dirk

    2015-01-01

    The importance of short membrane sequence motifs has been shown in many works and emphasizes the related sequence motif analysis. Together with specific transmembrane helix-helix interactions, the analysis of interacting sequence parts is helpful for understanding the process during membrane protein folding and in retaining the three-dimensional fold. Here we present a simple high-throughput analysis method for deriving mutational information of interacting sequence parts. Applied on aquaporin water channel proteins, our approach supports the analysis of mutational variants within different interacting subsequences and finally the investigation of natural variants which cause diseases like, for example, nephrogenic diabetes insipidus. In this work we demonstrate a simple method for massive membrane protein data analysis. As shown, the presented in silico analyses provide information about interacting sequence parts which are constrained by protein evolution. We present a simple graphical visualization medium for the representation of evolutionary influenced interaction pattern pairs (EIPPs) adapted to mutagen investigations of aquaporin-2, a protein whose mutants are involved in the rare endocrine disorder known as nephrogenic diabetes insipidus, and membrane proteins in general. Furthermore, we present a new method to derive new evolutionary variations within EIPPs which can be used for further mutagen laboratory investigations.

  3. Important factors stabilizing stacking interaction between 3-nitropyrrole and natural nucleobases revealed by ab initio calculations.

    PubMed

    Seio, Kohji; Ukawa, Hisashi; Shohda, Koh-ichiro; Sekine, Mitsuo

    2003-01-01

    Stacking energies between canonical nucleobases and a universal base, 3-nitropyrrole (3-NP), were estimated by use of molecular orbital (MO) and molecular mechanics (MM) calculations. The detailed analysis of the energy profiles revealed the importance of the London dispersion energy to stabilize the stacked dimers and electrostatic interactions to determine the orientation of 3-NP to the nucleobases in the dimers. Although the energy profiles of 3-NP/natural base dimers obtained by the MO and MM calculations were qualitatively correlated with each other, the correlations were poorer than those obtained for the stacking between natural bases. The origin of the difference between 3-NP and natural bases will be discussed to understand the possibility and limitation of the current MM calculations for the simulation and design of other universal bases.

  4. Interactions of Prosthetic and Natural Vision in Animals With Local Retinal Degeneration

    PubMed Central

    Lorach, Henri; Lei, Xin; Galambos, Ludwig; Kamins, Theodore; Mathieson, Keith; Dalal, Roopa; Huie, Philip; Harris, James; Palanker, Daniel

    2015-01-01

    Purpose Prosthetic restoration of partial sensory loss leads to interactions between artificial and natural inputs. Ideally, the rehabilitation should allow perceptual fusion of the two modalities. Here we studied the interactions between normal and prosthetic vision in a rodent model of local retinal degeneration. Methods Implantation of a photovoltaic array in the subretinal space of normally sighted rats induced local degeneration of the photoreceptors above the chip, and the inner retinal neurons in this area were electrically stimulated by the photovoltaic implant powered by near-infrared (NIR) light. We studied prosthetic and natural visually evoked potentials (VEP) in response to simultaneous stimulation by NIR and visible light patterns. Results We demonstrate that electrical and natural VEPs summed linearly in the visual cortex, and both responses decreased under brighter ambient light. Responses to visible light flashes increased over 3 orders of magnitude of contrast (flash/background), while for electrical stimulation the contrast range was limited to 1 order of magnitude. The maximum amplitude of the prosthetic VEP was three times lower than the maximum response to a visible flash over the same area on the retina. Conclusions Ambient light affects prosthetic responses, albeit much less than responses to visible stimuli. Prosthetic representation of contrast in the visual scene can be encoded, to a limited extent, by the appropriately calibrated stimulus intensity, which also depends on the ambient light conditions. Such calibration will be important for patients combining central prosthetic vision with natural peripheral sight, such as in age-related macular degeneration. PMID:26618643

  5. Contextual Interactions in Grating Plaid Configurations Are Explained by Natural Image Statistics and Neural Modeling

    PubMed Central

    Ernst, Udo A.; Schiffer, Alina; Persike, Malte; Meinhardt, Günter

    2016-01-01

    Processing natural scenes requires the visual system to integrate local features into global object descriptions. To achieve coherent representations, the human brain uses statistical dependencies to guide weighting of local feature conjunctions. Pairwise interactions among feature detectors in early visual areas may form the early substrate of these local feature bindings. To investigate local interaction structures in visual cortex, we combined psychophysical experiments with computational modeling and natural scene analysis. We first measured contrast thresholds for 2 × 2 grating patch arrangements (plaids), which differed in spatial frequency composition (low, high, or mixed), number of grating patch co-alignments (0, 1, or 2), and inter-patch distances (1° and 2° of visual angle). Contrast thresholds for the different configurations were compared to the prediction of probability summation (PS) among detector families tuned to the four retinal positions. For 1° distance the thresholds for all configurations were larger than predicted by PS, indicating inhibitory interactions. For 2° distance, thresholds were significantly lower compared to PS when the plaids were homogeneous in spatial frequency and orientation, but not when spatial frequencies were mixed or there was at least one misalignment. Next, we constructed a neural population model with horizontal laminar structure, which reproduced the detection thresholds after adaptation of connection weights. Consistent with prior work, contextual interactions were medium-range inhibition and long-range, orientation-specific excitation. However, inclusion of orientation-specific, inhibitory interactions between populations with different spatial frequency preferences were crucial for explaining detection thresholds. Finally, for all plaid configurations we computed their likelihood of occurrence in natural images. The likelihoods turned out to be inversely related to the detection thresholds obtained at larger

  6. Macro and micro scale interactions between cohesive sediment tracers and natural estuarine mud.

    NASA Astrophysics Data System (ADS)

    Spencer, K. L.; Manning, A. J.; Droppo, I. G.; Leppard, G. G.; Benson, T.

    2009-04-01

    Improving the understanding of dispersion patterns of the fine sediment fraction (< 63 micron) and associated contaminants is fundamental to the sustainable management of estuarine and marine environments. In order to develop sediment transport models and predict sediment dispersion, accurate and reliable field techniques for the measurement of sediment transport are required. Although this is relatively simple for the sand sized fraction, measuring transport pathways for the < 63 micron sediment fraction has been more problematic. There has been considerable effort within the scientific community to develop a tracer for the fine/cohesive sediment fraction. This has included the use of synthetic tracer particles and the labelling of natural clays (e.g. Mahler et al. 1998, Yin et al. 1999, Krezoski 1985; Spencer et al. 2007). Synthetic tracers have included polymer-based fluorescent tracers, with the same size, density and surface charge characteristics as the flocculated clay and silt fraction. A fundamental assumption of tracer technology is that the tracer has the same physical properties as the natural sediment it is intended to mimic. For sand-sized material matching particle size, shape and density has been easy to achieve. However, the < 63 micron sediment fraction is cohesive and in order to satisfy this assumption cohesive sediment tracers must be incorporated into and transported via floc aggregates (Black et al. 2006). This work focuses on the use of a labelled natural clay; a Ho-montmorillonite (see Spencer et al. 2007). The aim of the research was to determine whether this tracer interacted with and was transported via floc aggregates in saline environments and would therefore be a suitable cohesive sediment tracer in estuaries. Our objectives were to examine the physical characteristics, internal structure and settling dynamics of flocculated tracer and to determine the extent to which the tracer interacted with natural estuarine muds under laboratory

  7. On the Mapping of Epistatic Genetic Interactions in Natural Isolates: Combining Classical Genetics and Genomics.

    PubMed

    Hou, Jing; Schacherer, Joseph

    2016-01-01

    Genetic variation within species is the substrate of evolution. Epistasis, which designates the non-additive interaction between loci affecting a specific phenotype, could be one of the possible outcomes of genetic diversity. Dissecting the basis of such interactions is of current interest in different fields of biology, from exploring the gene regulatory network, to complex disease genetics, to the onset of reproductive isolation and speciation. We present here a general workflow to identify epistatic interactions between independently evolving loci in natural populations of the yeast Saccharomyces cerevisiae. The idea is to exploit the genetic diversity present in the species by evaluating a large number of crosses and analyzing the phenotypic distribution in the offspring. For a cross of interest, both parental strains would have a similar phenotypic value, whereas the resulting offspring would have a bimodal distribution of the phenotype, possibly indicating the presence of epistasis. Classical segregation analysis of the tetrads uncovers the penetrance and complexity of the interaction. In addition, this segregation could serve as the guidelines for choosing appropriate mapping strategies to narrow down the genomic regions involved. Depending on the segregation patterns observed, we propose different mapping strategies based on bulk segregant analysis or consecutive backcrosses followed by high-throughput genome sequencing. Our method is generally applicable to all systems with a haplodiplobiontic life cycle and allows high resolution mapping of interacting loci that govern various DNA polymorphisms from single nucleotide mutations to large-scale structural variations.

  8. Antimony in the environment: A review focused on natural waters. III. Microbiota relevant interactions

    NASA Astrophysics Data System (ADS)

    Filella, Montserrat; Belzile, Nelson; Lett, Marie-Claire

    2007-02-01

    Antimony is ubiquitously present in the environment as a result of natural processes and human activities. Antimony is not considered to be an essential element for plants or animals. In this third review paper on the occurrence of antimony in natural waters, the interactions of antimony with microbiota are discussed in relation to its fate in natural waters. This paper covers the following aspects: occurrence in microbiota, uptake transport mechanisms, pathways of Sb(III) removal from cells involved in antimony tolerance, oxidation and reduction of antimony by living organisms, phytochelatin induction and biomethylation. This review is based on a careful and systematic examination of a comprehensive collection of papers on the above mentioned aspects of the subject. All data are quoted from the original sources. Relatively little existing information falls within the strict scope of this review and, when relevant, discussion on the interactions of antimony with reference microorganisms, such as Escherichia coli, Saccharomyces cerevisiae and different protozoan parasites of the genus Leishmania, has been included.

  9. Modeling the Interaction Between Hydraulic and Natural Fractures Using Dual-Lattice Discrete Element Method

    SciTech Connect

    Zhou, Jing; Huang, Hai; Deo, Milind

    2015-10-01

    The interaction between hydraulic fractures (HF) and natural fractures (NF) will lead to complex fracture networks due to the branching and merging of natural and hydraulic fractures in unconventional reservoirs. In this paper, a newly developed hydraulic fracturing simulator based on discrete element method is used to predict the generation of complex fracture network in the presence of pre-existing natural fractures. By coupling geomechanics and reservoir flow within a dual lattice system, this simulator can effectively capture the poro-elastic effects and fluid leakoff into the formation. When HFs are intercepting single or multiple NFs, complex mechanisms such as direct crossing, arresting, dilating and branching can be simulated. Based on the model, the effects of injected fluid rate and viscosity, the orientation and permeability of NFs and stress anisotropy on the HF-NF interaction process are investigated. Combined impacts from multiple parameters are also examined in the paper. The numerical results show that large values of stress anisotropy, intercepting angle, injection rate and viscosity will impede the opening of NFs.

  10. Pollinator interactions with yellow starthistle (Centaurea solstitialis) across urban, agricultural, and natural landscapes.

    PubMed

    Leong, Misha; Kremen, Claire; Roderick, George K

    2014-01-01

    Pollinator-plant relationships are found to be particularly vulnerable to land use change. Yet despite extensive research in agricultural and natural systems, less attention has focused on these interactions in neighboring urban areas and its impact on pollination services. We investigated pollinator-plant interactions in a peri-urban landscape on the outskirts of the San Francisco Bay Area, California, where urban, agricultural, and natural land use types interface. We made standardized observations of floral visitation and measured seed set of yellow starthistle (Centaurea solstitialis), a common grassland invasive, to test the hypotheses that increasing urbanization decreases 1) rates of bee visitation, 2) viable seed set, and 3) the efficiency of pollination (relationship between bee visitation and seed set). We unexpectedly found that bee visitation was highest in urban and agricultural land use contexts, but in contrast, seed set rates in these human-altered landscapes were lower than in natural sites. An explanation for the discrepancy between floral visitation and seed set is that higher plant diversity in urban and agricultural areas, as a result of more introduced species, decreases pollinator efficiency. If these patterns are consistent across other plant species, the novel plant communities created in these managed landscapes and the generalist bee species that are favored by human-altered environments will reduce pollination services.

  11. Hsp12p and PAU genes are involved in ecological interactions between natural yeast strains.

    PubMed

    Rivero, Damaríz; Berná, Luisa; Stefanini, Irene; Baruffini, Enrico; Bergerat, Agnes; Csikász-Nagy, Attila; De Filippo, Carlotta; Cavalieri, Duccio

    2015-08-01

    The coexistence of different yeasts in a single vineyard raises the question on how they communicate and why slow growers are not competed out. Genetically modified laboratory strains of Saccharomyces cerevisiae are extensively used to investigate ecological interactions, but little is known about the genes regulating cooperation and competition in ecologically relevant settings. Here, we present evidences of Hsp12p-dependent altruistic and contact-dependent competitive interactions between two natural yeast isolates. Hsp12p is released during cell death for public benefit by a fast-growing strain that also produces a killer toxin to inhibit growth of a slow grower that can enjoy the benefits of released Hsp12p. We also show that the protein Pau5p is essential in the defense against the killer effect. Our results demonstrate that the combined action of Hsp12p, Pau5p and a killer toxin is sufficient to steer a yeast community.

  12. A review of natural aerosol interactions and feedbacks within the Earth system

    NASA Astrophysics Data System (ADS)

    Carslaw, K. S.; Boucher, O.; Spracklen, D. V.; Mann, G. W.; Rae, J. G. L.; Woodward, S.; Kulmala, M.

    2010-02-01

    The natural environment is a major source of atmospheric aerosols, including dust, secondary organic material from terrestrial biogenic emissions, carbonaceous particles from wildfires, and sulphate from marine phytoplankton dimethyl sulphide emissions. These aerosols also have a significant effect on many components of the Earth system such as the atmospheric radiative balance and photosynthetically available radiation entering the biosphere, the supply of nutrients to the ocean, and the albedo of snow and ice. The physical and biological systems that produce these aerosols can be highly susceptible to modification due to climate change so there is the potential for important climate feedbacks. We review the impact of these natural systems on atmospheric aerosol based on observations and models, including the potential for long term changes in emissions and the feedbacks on climate. The number of drivers of change is very large and the various systems are strongly coupled. There have therefore been very few studies that integrate the various effects to estimate climate feedback factors. Nevertheless, available observations and model studies suggest that the regional radiative perturbations are potentially several Watts per square metre due to changes in these natural aerosol emissions in a future climate. Taking into account only the direct radiative effect of changes in the atmospheric burden of natural aerosols, and neglecting potentially large effects on other parts of the Earth system, a global mean radiative perturbation approaching 1 W m-2 is possible by the end of the century. The level of scientific understanding of the climate drivers, interactions and impacts is very low.

  13. Modifying effects of phenotypic plasticity on interactions among natural selection, adaptation and gene flow.

    PubMed

    Crispo, E

    2008-11-01

    Divergent natural selection, adaptive divergence and gene flow may interact in a number of ways. Recent studies have focused on the balance between selection and gene flow in natural populations, and empirical work has shown that gene flow can constrain adaptive divergence, and that divergent selection can constrain gene flow. A caveat is that phenotypic diversification may be under the direct influence of environmental factors (i.e. it may be due to phenotypic plasticity), in addition to partial genetic influence. In this case, phenotypic divergence may occur between populations despite high gene flow that imposes a constraint on genetic divergence. Plasticity may dampen the effects of natural selection by allowing individuals to rapidly adapt phenotypically to new conditions, thus slowing adaptive genetic divergence. On the other hand, plasticity may promote future adaptive divergence by allowing populations to persist in novel environments. Plasticity may promote gene flow between selective regimes by allowing dispersers to adapt to alternate conditions, or high gene flow may result in the selection for increased plasticity. Here I expand frameworks for understanding relationships among selection, adaptation and gene flow to include the effects of phenotypic plasticity in natural populations, and highlight its importance in evolutionary diversification.

  14. Natural gas storage and end user interaction: A progress report, September 30, 1994--March 31, 1995

    SciTech Connect

    Crook, L.R. Jr.; Reich, S.; Godec, M.L.

    1995-07-01

    In late 1994, ICF Resources began a contract with the Morgantown Energy Technology Center (METC) to conduct a study of natural gas storage and end user interaction. This study is being conducted in three phases: the first phase is an assessment of the market requirements for natural gas storage and in particular to identify those end user requirements for storage that could benefit from METC-sponsored research and development (R&D) in storage technology; the second phase will address the particular technical and economic feasibility for expanding conventional storage; and the third phase will address alternative, unconventional technologies. ICF is approaching the conclusion of the first phase of the study and the second phase has begun. This paper summarizes the scope of the study and reports some of the preliminary findings of the first phase. We begin by providing an overview of the goals of the effort and of natural gas storage. We will address the evolving market requirements for storage and the regulatory and institutional changes that are having a major impact on the use of natural gas storage. We address the demand for storage and the alternatives for meeting this demand, with specific reference to regional and end use issues.

  15. Interaction of flavonoids, the naturally occurring antioxidants with different media: A UV-visible spectroscopic study

    NASA Astrophysics Data System (ADS)

    Naseem, Bushra; Shah, S. W. H.; Hasan, Aurangzeb; Sakhawat Shah, S.

    2010-04-01

    Quantitative parameters for interaction of flavonoids—the naturally occurring antioxidants, with solvents and surfactants are determined using UV-visible absorption spectroscopy. The availability of flavonoids; kaempferol, apigenin, kaempferide and rhamnetin in micelles of sodium dodecyl sulfate (SDS) is reflected in terms of partition coefficient, Kc. Thermodynamic calculations show that the process of transfer of flavonoid molecules to anionic micelles of SDS is energy efficient. A distortion in flavonoid's morphology occurs in case of kaempferol and apigenin in surfactant and water, exhibited in terms of a new band in the UV region of electronic spectra of these flavonoids. The partition coefficients of structurally related flavonoids are correlated with their antioxidant activities.

  16. Special issue: redox active natural products and their interaction with cellular signalling pathways.

    PubMed

    Jacob, Claus

    2014-11-26

    During the last decade, research into natural products has experienced a certain renaissance. The urgent need for more and more effective antibiotics in medicine, the demand for ecologically friendly plant protectants in agriculture, "natural" cosmetics and the issue of a sustainable and healthy nutrition in an ageing society have fuelled research into Nature's treasure chest of "green gold". Here, redox active secondary metabolites from plants, fungi, bacteria and other (micro-)organisms often have been at the forefront of the most interesting developments. These agents provide powerful means to interfere with many, probably most cellular signaling pathways in humans, animals and lower organisms, and therefore can be used to protect, i.e., in form of antioxidants, and to frighten off or even kill, i.e., in form of repellants, antibiotics, fungicides and selective, often catalytic "sensor/effector" anticancer agents. Interestingly, whilst natural product research dates back many decades, in some cases even centuries, and compounds such as allicin and various flavonoids have been investigated thoroughly in the past, it has only recently become possible to investigate their precise interactions and mode(s) of action inside living cells. Here, fluorescent staining and labelling on the one side, and appropriate detection, either qualitatively under the microscope or quantitatively in flow cytometers and plate readers, on the other, enable researchers to obtain the various pieces of information necessary to construct a fairly complete puzzle of how such compounds act and interact in living cells. Complemented by the more traditional activity assays and Western Blots, and increasingly joined by techniques such as proteomics, chemogenetic screening and mRNA profiling, these cell based bioanalytical techniques form a powerful platform for "intracellular diagnostics". In the case of redox active compounds, especially of Reactive Sulfur Species (RSS), such techniques have

  17. Assessing Natural Product-Drug Interactions: An End-to-End Safety Framework.

    PubMed

    Roe, Amy L; Paine, Mary F; Gurley, Bill J; Brouwer, Kenneth R; Jordan, Scott; Griffiths, James C

    2016-04-01

    The use of natural products (NPs), including herbal medicines and other dietary supplements, by North Americans continues to increase across all age groups. This population has access to conventional medications, with significant polypharmacy observed in older adults. Thus, the safety of the interactions between multi-ingredient NPs and drugs is a topic of paramount importance. Considerations such as history of safe use, literature data from animal toxicity and human clinical studies, and NP constituent characterization would provide guidance on whether to assess NP-drug interactions experimentally. The literature is replete with reports of various NP extracts and constituents as potent inhibitors of drug metabolizing enzymes, and transporters. However, without standard methods for NP characterization or in vitro testing, extrapolating these reports to clinically-relevant NP-drug interactions is difficult. This lack of a clear definition of risk precludes clinicians and consumers from making informed decisions about the safety of taking NPs with conventional medications. A framework is needed that describes an integrated robust approach for assessing NP-drug interactions; and, translation of the data into formulation alterations, dose adjustment, labelling, and/or post-marketing surveillance strategies. A session was held at the 41st Annual Summer Meeting of the Toxicology Forum in Colorado Springs, CO, to highlight the challenges and critical components that should be included in a framework approach.

  18. Impact and Influence of the Natural Vibrio-Squid Symbiosis in Understanding Bacterial–Animal Interactions

    PubMed Central

    Mandel, Mark J.; Dunn, Anne K.

    2016-01-01

    Animals are colonized by bacteria, and in many cases partners have co-evolved to perform mutually beneficial functions. An exciting and ongoing legacy of the past decade has been an expansion of technology to enable study of natural associations in situ/in vivo. As a result, more symbioses are being examined, and additional details are being revealed for well-studied systems with a focus on the interactions between partners in the native context. With this framing, we review recent literature from the Vibrio fischeri–Euprymna scolopes symbiosis and focus on key studies that have had an impact on understanding bacteria–animal interactions broadly. This is not intended to be a comprehensive review of the system, but rather to focus on particular studies that have excelled at moving from pattern to process in facilitating an understanding of the molecular basis to intriguing observations in the field of host–microbe interactions. In this review we discuss the following topics: processes regulating strain and species specificity; bacterial signaling to host morphogenesis; multiple roles for nitric oxide; flagellar motility and chemotaxis; and efforts to understand unannotated and poorly annotated genes. Overall these studies demonstrate how functional approaches in vivo in a tractable system have provided valuable insight into general principles of microbe–host interactions. PMID:28018314

  19. Impact and Influence of the Natural Vibrio-Squid Symbiosis in Understanding Bacterial-Animal Interactions.

    PubMed

    Mandel, Mark J; Dunn, Anne K

    2016-01-01

    Animals are colonized by bacteria, and in many cases partners have co-evolved to perform mutually beneficial functions. An exciting and ongoing legacy of the past decade has been an expansion of technology to enable study of natural associations in situ/in vivo. As a result, more symbioses are being examined, and additional details are being revealed for well-studied systems with a focus on the interactions between partners in the native context. With this framing, we review recent literature from the Vibrio fischeri-Euprymna scolopes symbiosis and focus on key studies that have had an impact on understanding bacteria-animal interactions broadly. This is not intended to be a comprehensive review of the system, but rather to focus on particular studies that have excelled at moving from pattern to process in facilitating an understanding of the molecular basis to intriguing observations in the field of host-microbe interactions. In this review we discuss the following topics: processes regulating strain and species specificity; bacterial signaling to host morphogenesis; multiple roles for nitric oxide; flagellar motility and chemotaxis; and efforts to understand unannotated and poorly annotated genes. Overall these studies demonstrate how functional approaches in vivo in a tractable system have provided valuable insight into general principles of microbe-host interactions.

  20. Preparation of anhydrothrombin and characterization of its interaction with natural thrombin substrates.

    PubMed Central

    Hosokawa, K; Ohnishi, T; Shima, M; Nagata, M; Koide, T

    2001-01-01

    Thrombin is a serine proteinase that plays a key role in thrombosis and haemostasis through its interaction with several coagulation factors. Anhydrothrombin was prepared from PMSF-inactivated thrombin under alkaline conditions, and the folded anhydrothrombin was successfully recovered after dialysis in the presence of glycerol. Anhydro-derivatives of factor Xa, factor VIIa and activated protein C could also be prepared essentially by the same procedure. Anhydrothrombin retained affinity for various natural substrates of thrombin, including fibrinogen, factor VIII, factor XIII and protein C. In addition, these proteins were bound to anhydrothrombin-agarose in a reversible manner. The K(d) values for factor VIII, fibrinogen, factor XIII and protein C were 1.2x10(-8), 4.4x10(-8), 2.8x10(-7) and 8.1x10(-5) M, respectively. Thus thrombin substrates known to interact with the exosite I of thrombin demonstrated high affinity for anhydrothrombin. Furthermore, in the presence of Na+, substantial enhancement of the association rate constant (k(ass)) was observed for interactions of fibrinogen and factor VIII with anhydrothrombin. These results suggest that anhydrothrombin is useful in the purification of thrombin substrate proteins as well as in the investigation of detailed interactions between thrombin and these substrates in their activation or degradation processes. PMID:11171108

  1. Nature of amine-surfactant interactions at the air-solution interface.

    PubMed

    Penfold, J; Thomas, R K; Zhang, X L; Taylor, D J F

    2009-04-07

    significant in the context of understanding the unusual nature of the PEI/surfactant interaction and of using small molecular weight additives rather than much larger molecular weight polymers to manipulate adsorption properties.

  2. Metabolic Network Modeling of Microbial Interactions in Natural and Engineered Environmental Systems.

    PubMed

    Perez-Garcia, Octavio; Lear, Gavin; Singhal, Naresh

    2016-01-01

    We review approaches to characterize metabolic interactions within microbial communities using Stoichiometric Metabolic Network (SMN) models for applications in environmental and industrial biotechnology. SMN models are computational tools used to evaluate the metabolic engineering potential of various organisms. They have successfully been applied to design and optimize the microbial production of antibiotics, alcohols and amino acids by single strains. To date however, such models have been rarely applied to analyze and control the metabolism of more complex microbial communities. This is largely attributed to the diversity of microbial community functions, metabolisms, and interactions. Here, we firstly review different types of microbial interaction and describe their relevance for natural and engineered environmental processes. Next, we provide a general description of the essential methods of the SMN modeling workflow including the steps of network reconstruction, simulation through Flux Balance Analysis (FBA), experimental data gathering, and model calibration. Then we broadly describe and compare four approaches to model microbial interactions using metabolic networks, i.e., (i) lumped networks, (ii) compartment per guild networks, (iii) bi-level optimization simulations, and (iv) dynamic-SMN methods. These approaches can be used to integrate and analyze diverse microbial physiology, ecology and molecular community data. All of them (except the lumped approach) are suitable for incorporating species abundance data but so far they have been used only to model simple communities of two to eight different species. Interactions based on substrate exchange and competition can be directly modeled using the above approaches. However, interactions based on metabolic feedbacks, such as product inhibition and synthropy require extensions to current models, incorporating gene regulation and compounding accumulation mechanisms. SMN models of microbial interactions can

  3. Metabolic Network Modeling of Microbial Interactions in Natural and Engineered Environmental Systems

    PubMed Central

    Perez-Garcia, Octavio; Lear, Gavin; Singhal, Naresh

    2016-01-01

    We review approaches to characterize metabolic interactions within microbial communities using Stoichiometric Metabolic Network (SMN) models for applications in environmental and industrial biotechnology. SMN models are computational tools used to evaluate the metabolic engineering potential of various organisms. They have successfully been applied to design and optimize the microbial production of antibiotics, alcohols and amino acids by single strains. To date however, such models have been rarely applied to analyze and control the metabolism of more complex microbial communities. This is largely attributed to the diversity of microbial community functions, metabolisms, and interactions. Here, we firstly review different types of microbial interaction and describe their relevance for natural and engineered environmental processes. Next, we provide a general description of the essential methods of the SMN modeling workflow including the steps of network reconstruction, simulation through Flux Balance Analysis (FBA), experimental data gathering, and model calibration. Then we broadly describe and compare four approaches to model microbial interactions using metabolic networks, i.e., (i) lumped networks, (ii) compartment per guild networks, (iii) bi-level optimization simulations, and (iv) dynamic-SMN methods. These approaches can be used to integrate and analyze diverse microbial physiology, ecology and molecular community data. All of them (except the lumped approach) are suitable for incorporating species abundance data but so far they have been used only to model simple communities of two to eight different species. Interactions based on substrate exchange and competition can be directly modeled using the above approaches. However, interactions based on metabolic feedbacks, such as product inhibition and synthropy require extensions to current models, incorporating gene regulation and compounding accumulation mechanisms. SMN models of microbial interactions can

  4. Classifying a Person's Degree of Accessibility From Natural Body Language During Social Human-Robot Interactions.

    PubMed

    McColl, Derek; Jiang, Chuan; Nejat, Goldie

    2017-02-01

    For social robots to be successfully integrated and accepted within society, they need to be able to interpret human social cues that are displayed through natural modes of communication. In particular, a key challenge in the design of social robots is developing the robot's ability to recognize a person's affective states (emotions, moods, and attitudes) in order to respond appropriately during social human-robot interactions (HRIs). In this paper, we present and discuss social HRI experiments we have conducted to investigate the development of an accessibility-aware social robot able to autonomously determine a person's degree of accessibility (rapport, openness) toward the robot based on the person's natural static body language. In particular, we present two one-on-one HRI experiments to: 1) determine the performance of our automated system in being able to recognize and classify a person's accessibility levels and 2) investigate how people interact with an accessibility-aware robot which determines its own behaviors based on a person's speech and accessibility levels.

  5. Different types of interactions of links in artificial and natural ecosystems under anthropogenic pressure

    NASA Astrophysics Data System (ADS)

    Somova, Lydia; Pisman, Tamara; Mikheeva, Galina; Pechurkin, Nickolay

    The life of organisms in an ecosystem depends not only on abiotic factors, but also on the interaction of organisms in which they come with each other. The study of mechanisms of the bioregulation based on ecological - biochemical interactions of ecosystem links is necessary to know the ecosystem development, its stability, survival of ecosystem organisms. It is of high importance as for the creation of artificial ecosystems, and also for the study of natural ecosystems under anthropogenic pressure on them. To create well-functioning ecosystems is necessary to study and consider the basic types of relationships between organisms. The basic types of interactions between organisms have been studied with simple terrestrial and water ecosystems. 1. The interaction of microbiocenoses and plants were studied in experiments with agrocenoses. Microbiocenosis proposed for increase of productivity of plants and for obtaining ecologically pure production of plants has been created taking into account mutual relationships between species of microorganisms. 2. The experimental model of the atmosphere closed «autotroph - heterotroph» system in which heterotrophic link was the mixed population of yeasts (Candida utilis and Candida guilliermondii) was studied. The algae Chlorella vulgaris was used as an autotroph link. It was shown, that the competition result for heterotrophic link depended on strategy of populations of yeast in relation to a substrate and oxygen utilization. 3. As a result of experimental and theoretical modelling of a competition of algae Chlorella vulgaris and Scenedesmus quadricauda at continuous cultivation, the impossibility of their coexistence in the conditions of limitation on nitrogen was shown. 4. Pray-predator interactions between algae (Chlorella vulgaris, Scenedesmus quadricauda) and invertebrates (Paramecium caudatum, Brachionus plicatilis) were studied in experimental closed ecosystem. This work was partly supported by the Russian Foundation for

  6. Milk Thistle Constituents Inhibit Raloxifene Intestinal Glucuronidation: A Potential Clinically Relevant Natural Product-Drug Interaction.

    PubMed

    Gufford, Brandon T; Chen, Gang; Vergara, Ana G; Lazarus, Philip; Oberlies, Nicholas H; Paine, Mary F

    2015-09-01

    Women at high risk of developing breast cancer are prescribed selective estrogen response modulators, including raloxifene, as chemoprevention. Patients often seek complementary and alternative treatment modalities, including herbal products, to supplement prescribed medications. Milk thistle preparations, including silibinin and silymarin, are top-selling herbal products that may be consumed by women taking raloxifene, which undergoes extensive first-pass glucuronidation in the intestine. Key constituents in milk thistle, flavonolignans, were previously shown to be potent inhibitors of intestinal UDP-glucuronosyl transferases (UGTs), with IC50s ≤ 10 μM. Taken together, milk thistle preparations may perpetrate unwanted interactions with raloxifene. The objective of this work was to evaluate the inhibitory effects of individual milk thistle constituents on the intestinal glucuronidation of raloxifene using human intestinal microsomes and human embryonic kidney cell lysates overexpressing UGT1A1, UGT1A8, and UGT1A10, isoforms highly expressed in the intestine that are critical to raloxifene clearance. The flavonolignans silybin A and silybin B were potent inhibitors of both raloxifene 4'- and 6-glucuronidation in all enzyme systems. The Kis (human intestinal microsomes, 27-66 µM; UGT1A1, 3.2-8.3 µM; UGT1A8, 19-73 µM; and UGT1A10, 65-120 µM) encompassed reported intestinal tissue concentrations (20-310 µM), prompting prediction of clinical interaction risk using a mechanistic static model. Silibinin and silymarin were predicted to increase raloxifene systemic exposure by 4- to 5-fold, indicating high interaction risk that merits further evaluation. This systematic investigation of the potential interaction between a widely used herbal product and chemopreventive agent underscores the importance of understanding natural product-drug interactions in the context of cancer prevention.

  7. Abundance and phenology patterns of two pond-breeding salamanders determine species interactions in natural populations.

    PubMed

    Anderson, Thomas L; Hocking, Daniel J; Conner, Christopher A; Earl, Julia E; Harper, Elizabeth B; Osbourn, Michael S; Peterman, William E; Rittenhouse, Tracy A G; Semlitsch, Raymond D

    2015-03-01

    Phenology often determines the outcome of interspecific interactions, where early-arriving species often dominate interactions over those arriving later. The effects of phenology on species interactions are especially pronounced in aquatic systems, but the evidence is largely derived from experimental studies. We examined whether differences in breeding phenology between two pond-breeding salamanders (Ambystoma annulatum and A. maculatum) affected metamorph recruitment and demographic traits within natural populations, with the expectation that the fall-breeding A. annulatum would negatively affect the spring-breeding A. maculatum. We monitored populations of each species at five ponds over 4 years using drift fences. Metamorph abundance and survival of A. annulatum were affected by intra- and interspecific processes, whereas metamorph size and date of emigration were primarily influenced by intraspecific effects. Metamorph abundance, snout-vent length, date of emigration and survival for A. maculatum were all predicted by combinations of intra- and interspecific effects, but often showed negative relationships with A. annulatum metamorph traits and abundance. Size and date of metamorphosis were strongly correlated within each species, but in opposite patterns (negative for A. annulatum and positive for A. maculatum), suggesting that the two species use alternative strategies to enhance terrestrial survival and that these factors may influence their interactions. Our results match predictions from experimental studies that suggest recruitment is influenced by intra- and interspecific processes which are determined by phenological differences between species. Incorporating spatiotemporal variability when modeling population dynamics is necessary to understand the importance of phenology in species interactions, especially as shifts in phenology occur under climate change.

  8. Rethink Disposable: Packaging Waste Source Reduction Pilot Project

    EPA Pesticide Factsheets

    Information about the SFBWQP Rethink Disposable: Packaging Waste Source Reduction Pilot Project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  9. Paracelsus's conception of seeds: rethinking Paracelsus's ideas of body and matter.

    PubMed

    Cislo, Amy Eisen

    2008-11-01

    This article examines how Paracelsus understands seeds in his notion of corporeality in his early works. In his article, "Invisible Wombs: Rethinking Paracelsus's Concept of Body and Matter" (Ambix 53.2), Dane Thor Daniel classified the Archiodoxen of 1527 as Paracelsus's early work. My essay argues that Archiodoxen demonstrates a development in Paracelsus's thinking, and suggests how Buch von der Gebärung (ca. 1520) and Volumen Paramirum (ca. 1520) represent Paracelsus's human seed theory in its earliest stages. In these works, Paracelsus does not necessarily base his seed theory entirely on scripture, but rather focuses on the relationship between nature and the human seed.

  10. Rethinking the Poverty-disease Nexus: the Case of HIV/AIDS in South Africa.

    PubMed

    Pienaar, Kiran

    2015-12-19

    While it is well-established that poverty and disease are intimately connected, the nature of this connection and the role of poverty in disease causation remains contested in scientific and social studies of disease. Using the case of HIV/AIDS in South Africa and drawing on a theoretically grounded analysis, this paper reconceptualises disease and poverty as ontologically entangled. In the context of the South African HIV epidemic, this rethinking of the poverty-disease dynamic enables an account of how social forces such as poverty become embodied in the very substance of disease to produce ontologies of HIV/AIDS unique to South Africa.

  11. Simulated pond-aquifer interactions under natural and stressed conditions near Snake Pond, Cape Cod, Massachusetts

    USGS Publications Warehouse

    Walter, Donald A.; Masterson, John P.; LeBlanc, Denis R.

    2002-01-01

    A numerical model was used to simulate pond-aquifer interactions under natural and stressed conditions near Snake Pond, Cape Cod, Massachusetts. Simulation results show that pond-bottom hydraulic conductivity, which represents the degree of hydraulic connection between the pond and the aquifer, is an important control on these interactions. As this parameter was incrementally increased from 10 to 350 feet per day, the rate of ground-water inflow into the pond under natural conditions increased by about 250 percent, the associated residence times of water in the pond decreased by about 50 percent, and ground-water inflow to the pond shifted closer to the pond shore. Most ground-water inflow (90 to 98 percent) was in the upper model layer, which corresponded to shallow, near-shore areas of the pond, over the entire range of pond-bottom hydraulic conductivity. Ground-water flow paths into the pond became more vertical, the contributing area to the pond became larger, and the pond captured water from greater depths in the aquifer as the hydraulic conductivity of the pond bottom was increased. The pond level, however, remained nearly constant, and regional ground-water levels and gradients differed little over the range of pond-bottom hydraulic conductivity, indicating that calibrated models with similar head solutions can have different pond-aquifer interaction characteristics. Hydrologic stresses caused by a simulated plume-containment system that specifies the extraction and injection of large volumes of ground water near the pond increased the pond level by about 0.4 foot and ground-water inflow rates into the pond by about 25 percent. Several factors related to the operation of the simulated containment system are affected by the hydraulic conductivity of the pond bottom. With increasing pond-bottom hydraulic conductivity, the amount of injected water that flows into Snake Pond increased and the amount of water recirculated between extraction and injection wells

  12. Investigation of adverse effects of interactions between herbal drugs and natural blood clotting mechanism.

    PubMed

    Adhyapak, M S; Kachole, M S

    2016-05-01

    Throughout the world, herbal medicines are consumed by most of the patients without considering their adverse effects. Many herbal medicines/plant extracts have been reported to interact with the natural blood clotting system. In continuation to this effort, thirty medicinal plant extracts were allowed to interact with citrated human blood and the clotting time was measured after re-calcification in vitro using Lee and White method. The aq. leaf ext. of Syzygium cumini and Camellia sinensis significantly prolonged the clotting time. In response to the prothrombin time and activated partial thromboplastin time tests, the ext. of C. sinensis showed normal APTT and marginally prolonged the PT to 16.7 s (control-15.2 s) while S. cumini showed normal PT but significantly prolonged the APTT to 66.9 s (control-20.7 s). This suggests that, C. sinensis acts on the extrinsic pathway while S. cumini on the intrinsic pathway. There are some common herbal formulations that are frequently used by the patients which contain above plant materials, like, Syzygium cumin in anti-diabetic formulations, while the ext. of C. sinensis is consumed frequently as beverage in many part of the world. Hence, patients having known bleeding tendency or haemophilia disease should take into account the interaction potential of these plants with the natural blood clotting system while taking herbal formulations containing above plants; specially, the patients suffering from intrinsic pathway factor deficiency should keep a limit on the consumption of S. cumini while extrinsic pathway factor deficiency patients should limit C. sinensis. Also, the medical practitioners should consider the patient's food consumption history before doing any major surgical procedures.

  13. Integrating natural language processing and web GIS for interactive knowledge domain visualization

    NASA Astrophysics Data System (ADS)

    Du, Fangming

    Recent years have seen a powerful shift towards data-rich environments throughout society. This has extended to a change in how the artifacts and products of scientific knowledge production can be analyzed and understood. Bottom-up approaches are on the rise that combine access to huge amounts of academic publications with advanced computer graphics and data processing tools, including natural language processing. Knowledge domain visualization is one of those multi-technology approaches, with its aim of turning domain-specific human knowledge into highly visual representations in order to better understand the structure and evolution of domain knowledge. For example, network visualizations built from co-author relations contained in academic publications can provide insight on how scholars collaborate with each other in one or multiple domains, and visualizations built from the text content of articles can help us understand the topical structure of knowledge domains. These knowledge domain visualizations need to support interactive viewing and exploration by users. Such spatialization efforts are increasingly looking to geography and GIS as a source of metaphors and practical technology solutions, even when non-georeferenced information is managed, analyzed, and visualized. When it comes to deploying spatialized representations online, web mapping and web GIS can provide practical technology solutions for interactive viewing of knowledge domain visualizations, from panning and zooming to the overlay of additional information. This thesis presents a novel combination of advanced natural language processing - in the form of topic modeling - with dimensionality reduction through self-organizing maps and the deployment of web mapping/GIS technology towards intuitive, GIS-like, exploration of a knowledge domain visualization. A complete workflow is proposed and implemented that processes any corpus of input text documents into a map form and leverages a web

  14. The interaction of Saccharomyces paradoxus with its natural competitors on oak bark.

    PubMed

    Kowallik, Vienna; Miller, Eric; Greig, Duncan

    2015-04-01

    The natural history of the model yeast Saccharomyces cerevisiae is poorly understood and confounded by domestication. In nature, S. cerevisiae and its undomesticated relative S. paradoxus are usually found on the bark of oak trees, a habitat very different from wine or other human fermentations. It is unclear whether the oak trees are really the primary habitat for wild yeast, or whether this apparent association is due to biased sampling. We use culturing and high-throughput environmental sequencing to show that S. paradoxus is a very rare member of the oak bark microbial community. We find that S. paradoxus can grow well on sterile medium made from oak bark, but that its growth is strongly suppressed when the other members of the community are present. We purified a set of twelve common fungal and bacterial species from the oak bark community and tested how each affected the growth of S. paradoxus in direct competition on oak bark medium at summer and winter temperatures, identifying both positive and negative interactions. One Pseudomonas species produces a diffusible toxin that suppresses S. paradoxus as effectively as either the whole set of twelve species together or the complete community present in nonsterilized oak medium. Conversely, one of the twelve species, Mucilaginibacter sp., had the opposite effect and promoted S. paradoxus growth at low temperatures. We conclude that, in its natural oak tree habitat, S. paradoxus is a rare species whose success depends on the much more abundant microbial species surrounding it.

  15. The interaction of Saccharomyces paradoxus with its natural competitors on oak bark

    PubMed Central

    Kowallik, Vienna; Miller, Eric; Greig, Duncan

    2015-01-01

    The natural history of the model yeast Saccharomyces cerevisiae is poorly understood and confounded by domestication. In nature, S. cerevisiae and its undomesticated relative S. paradoxus are usually found on the bark of oak trees, a habitat very different from wine or other human fermentations. It is unclear whether the oak trees are really the primary habitat for wild yeast, or whether this apparent association is due to biased sampling. We use culturing and high-throughput environmental sequencing to show that S. paradoxus is a very rare member of the oak bark microbial community. We find that S. paradoxus can grow well on sterile medium made from oak bark, but that its growth is strongly suppressed when the other members of the community are present. We purified a set of twelve common fungal and bacterial species from the oak bark community and tested how each affected the growth of S. paradoxus in direct competition on oak bark medium at summer and winter temperatures, identifying both positive and negative interactions. One Pseudomonas species produces a diffusible toxin that suppresses S. paradoxus as effectively as either the whole set of twelve species together or the complete community present in nonsterilized oak medium. Conversely, one of the twelve species, Mucilaginibacter sp., had the opposite effect and promoted S. paradoxus growth at low temperatures. We conclude that, in its natural oak tree habitat, S. paradoxus is a rare species whose success depends on the much more abundant microbial species surrounding it. PMID:25706044

  16. Effects of structure on the interactions between five natural antimicrobial compounds and phospholipids of bacterial cell membrane on model monolayers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Monolayers composed of bacterial phospholipids were used as model membranes to study interactions of naturally occurring phenolic compounds 2,5-dihydroxybenzaldehyde, 2-hydroxy-5-methoxybenzaldehyde and the plant essential oil compounds carvacrol, cinnamaldehyde, and geraniol, previously found to be...

  17. The nature and role of the gold-krypton interactions in small neutral gold clusters.

    PubMed

    Mancera, Luis A; Benoit, David M

    2015-03-26

    We investigate the nature and role of krypton embedding in small neutral gold clusters. For some of these clusters, we observe a particular site-dependent character of the Kr binding that does not completely follow the criterion of binding at low-coordinated sites, widely accepted for interaction of a noble gas with closed-shell metal systems such as metal surfaces. We aim at understanding the effect of low dimensionality and open-shell electronic structure of the odd-numbered clusters on the noble gas-metal cluster interaction. First, we investigate the role of attractive and repulsive forces, and the frontier molecular orbitals. Second, we investigate the Au-Kr interaction in terms of reactivity and bonding character. We use a reactivity index derived from Fukui formalism, and criteria provided by the electron localization function (ELF), in order to classify the type of bonding. We carry out this study on the minimum energy structures of neutral gold clusters, as obtained using pseudo potential plane-wave density functional theory (DFT). A model is proposed that includes the effect of attractive electrostatic, van der Waals and repulsive forces, together with effects originating from orbital overlap. This satisfactorily explains minimum configurations of the noble gas-gold cluster systems, the site preference of the noble gas atoms, and changes in electronic properties.

  18. Collective interaction of microscale matters in natural analogy: human cancer cells vs. microspheres

    NASA Astrophysics Data System (ADS)

    Ahn, Sungsook; Lee, Sang Joon; Postech Team

    2014-11-01

    Collective behaviors have been considered both in living and lifeless things as a natural phenomenon. During the ordering process, a sudden and spontaneous transition is typically generated between an order and a disorder according to the population density of interacting elements. In a cellular level collective behavior, the cells are distributed in the characteristic patterns according to the population density and the mutual interaction of the individual cells undergo density-dependent diffusive motion. On the other hand, density-controlled surface-modified hollow microsphere suspension induces an overpopulation via buoyancy which provides a driving force to induce an assembly. The collective behaviors of the cells and microspheres in a designed liquid medium are explained in terms of the deviation from the interparticle distance distribution and the induced strength to organize the particle position in a specific distance range. as a result, microscale particulate matters exhibit high resemblance in their pair correlation and dynamical heterogeneity in the intermediate range between a single individual and an agglomerate. Therefore, it is suggested that biological systems are analogically explained to be dominated by physically interactive aspects.

  19. Interactions of graphene oxide nanomaterials with natural organic matter and metal oxide surfaces.

    PubMed

    Chowdhury, Indranil; Duch, Matthew C; Mansukhani, Nikhita D; Hersam, Mark C; Bouchard, Dermont

    2014-08-19

    Interactions of graphene oxide (GO) nanomaterials with natural organic matter (NOM) and metal oxide surfaces were investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D). Three different types of NOM were studied: Suwannee River humic and fulvic acids (SRHA and SRFA) and alginate. Aluminum oxide surface was used as a model metal oxide surface. Deposition trends show that GO has the highest attachment on alginate, followed by SRFA, SRHA, and aluminum oxide surfaces, and that GO displayed higher interactions with all investigated surfaces than with silica. Deposition and release behavior of GO on aluminum oxide surface is very similar to positively charged poly-L-lysine-coated surface. Higher interactions of GO with NOM-coated surfaces are attributed to the hydroxyl, epoxy, and carboxyl functional groups of GO; higher deposition on alginate-coated surfaces is attributed to the rougher surface created by the extended conformation of the larger alginate macromolecules. Both ionic strength (IS) and ion valence (Na(+) vs Ca(2+)) had notable impact on interactions of GO with different environmental surfaces. Due to charge screening, increased IS resulted in greater deposition for NOM-coated surfaces. Release behavior of deposited GO varied significantly between different environmental surfaces. All surfaces showed significant release of deposited GO upon introduction of low IS water, indicating that deposition of GO on these surfaces is reversible. Release of GO from NOM-coated surfaces decreased with IS due to charge screening. Release rates of deposited GO from alginate-coated surface were significantly lower than from SRHA and SRFA-coated surfaces due to trapping of GO within the rough surface of the alginate layer.

  20. The front line of social capital creation--a natural experiment in symbolic interaction.

    PubMed

    Patulny, Roger; Siminski, Peter; Mendolia, Silvia

    2015-01-01

    This paper offers theoretical and empirical contributions to understanding the micro-sociological processes behind the creation of social capital. Theoretically, we argue that the emotional and shared experience of participating in symbolic interaction rituals may affect social capital in four different ways, via: (i) a 'citizenship' effect, connecting participants symbolically to the broader, civic society; (ii) a 'supportive' effect, bonding participants with each other; (iii) an exclusive 'tribal' effect, which crowds-out connections with other groups and the wider society; and (iv) an 'atomising' effect, whereby intense experiences create mental health problems that damage social capital. We illustrate this with a case study of Australian veterans of the Vietnam War. The randomness of the National Service conscription lotteries of that era translates into a high-quality natural experiment. We formulate several hypotheses about which of the four effects dominates for veterans who participated in the 'symbolic interaction' of training and deployment. We test these hypotheses using data from the 2006 Australian Census of Population and Housing, and the NSW 45 & Up Study. We found that war service reduced 'bonding' social capital, but increased 'bridging' social capital, and this is not explained completely by mental health problems. This suggests that while the combined 'tribal' and 'atomizing' effects of service outweigh the 'supportive' effects, the 'citizenship' effect is surprisingly robust. Although they feel unsupported and isolated, veterans are committed to their community and country. These paradoxical findings suggest that social capital is formed through symbolic interaction. The emotional and symbolic qualities of interaction rituals may formulate non-strategic (perhaps irrational) connections with society regardless of the status of one's personal support networks.

  1. Interactions Between Trypanosoma cruzi the Chagas Disease Parasite and Naturally Infected Wild Mepraia Vectors of Chile.

    PubMed

    Campos-Soto, Ricardo; Ortiz, Sylvia; Cordova, Ivan; Bruneau, Nicole; Botto-Mahan, Carezza; Solari, Aldo

    2016-03-01

    Chagas disease, which ranks among the world's most neglected diseases, is a chronic, systemic, parasitic infection caused by the protozoan Trypanosoma cruzi. Mepraia species are the wild vectors of this parasite in Chile. Host-parasite interactions can occur at several levels, such as co-speciation and ecological host fitting, among others. Thus, we are exploring the interactions between T. cruzi circulating in naturally infected Mepraia species in all areas endemic of Chile. We evaluated T. cruzi infection rates of 27 different haplotypes of the wild Mepraia species and identified their parasite genotypes using minicircle PCR amplification and hybridization tests with genotype-specific DNA probes. Infection rates were lower in northern Chile where Mepraia gajardoi circulates (10-35%); in central Chile, Mepraia spinolai is most abundant, and infection rates varied in space and time (0-55%). T. cruzi discrete typing units (DTUs) TcI, TcII, TcV, and Tc VI were detected. Mixed infections with two or more DTUs are frequently found in highly infected insects. T. cruzi DTUs have distinct, but not exclusive, ecological and epidemiological associations with their hosts. T. cruzi infection rates of M. spinolai were higher than in M. gajardoi, but the presence of mixed infection with more than one T. cruzi DTU was the same. The same T. cruzi DTUs (TcI, TcII, TcV, and TcVI) were found circulating in both vector species, even though TcI was not equally distributed. These results suggest that T. cruzi DTUs are not associated with any of the two genetically related vector species nor with the geographic area. The T. cruzi vectors interactions are discussed in terms of old and recent events. By exploring T. cruzi DTUs present in Mepraia haplotypes and species from northern to central Chile, we open the analysis on these invertebrate host-parasite interactions.

  2. The Dorsal Medial Prefrontal Cortex Responds Preferentially to Social Interactions during Natural Viewing

    PubMed Central

    Kelley, William M.; Haxby, James V.; Heatherton, Todd F.

    2016-01-01

    Humans display a strong tendency to make spontaneous inferences concerning the thoughts and intentions of others. Although this ability relies upon the concerted effort of multiple brain regions, the dorsal medial prefrontal cortex (DMPFC) is most closely associated with the ability to reason about other people's mental states and form impressions of their character. Here, we investigated this region's putative social category preference using fMRI as 34 participants engaged in uninstructed viewing of a complex naturalistic stimulus. Using a data-driven “reverse correlation” approach, we characterize the DMPFC's stimulus response profile from ongoing neural responses to a dynamic movie stimulus. Results of this analysis demonstrate that the DMPFC's response profile is dominated by the presence of scenes involving social interactions between characters. Subsequent content analysis of video clips created from this response profile confirmed this finding. In contrast, regions of the inferotemporal and parietal cortex were selectively tuned to faces and actions, both features that often covary with social interaction but may be difficult to disentangle using standard event-related approaches. Together, these findings suggest that the DMPFC is finely tuned for processing social interaction above other categories and that this preference is maintained during unrestricted viewing of complex natural stimuli such as movies. SIGNIFICANCE STATEMENT Recently, studies have brought into question whether the dorsal medial prefrontal cortex (DMPFC), a region long associated with social cognition, is specialized for the processing of social information. We examine the response profile of this region during natural viewing of a reasonably naturalistic stimulus (i.e., a Hollywood movie) using a data-driven reverse correlation technique. Our findings demonstrate that, during natural viewing, the DMPFC is strongly tuned to the social features of the stimulus above other categories

  3. Interaction-based evolution: how natural selection and nonrandom mutation work together

    PubMed Central

    2013-01-01

    Background The modern evolutionary synthesis leaves unresolved some of the most fundamental, long-standing questions in evolutionary biology: What is the role of sex in evolution? How does complex adaptation evolve? How can selection operate effectively on genetic interactions? More recently, the molecular biology and genomics revolutions have raised a host of critical new questions, through empirical findings that the modern synthesis fails to explain: for example, the discovery of de novo genes; the immense constructive role of transposable elements in evolution; genetic variance and biochemical activity that go far beyond what traditional natural selection can maintain; perplexing cases of molecular parallelism; and more. Presentation of the hypothesis Here I address these questions from a unified perspective, by means of a new mechanistic view of evolution that offers a novel connection between selection on the phenotype and genetic evolutionary change (while relying, like the traditional theory, on natural selection as the only source of feedback on the fit between an organism and its environment). I hypothesize that the mutation that is of relevance for the evolution of complex adaptation—while not Lamarckian, or “directed” to increase fitness—is not random, but is instead the outcome of a complex and continually evolving biological process that combines information from multiple loci into one. This allows selection on a fleeting combination of interacting alleles at different loci to have a hereditary effect according to the combination’s fitness. Testing and implications of the hypothesis This proposed mechanism addresses the problem of how beneficial genetic interactions can evolve under selection, and also offers an intuitive explanation for the role of sex in evolution, which focuses on sex as the generator of genetic combinations. Importantly, it also implies that genetic variation that has appeared neutral through the lens of traditional

  4. The Impact of Interactive Computer Simulations on the Nature and Quality of Postgraduate Science Teachers' Explanations in Physics

    ERIC Educational Resources Information Center

    Zacharia, Zacharias C.

    2005-01-01

    This study investigated how individuals' construction of explanations--a way of ascertaining how well an individual understands a concept--develops from an interactive simulation. Specifically, the purpose was to investigate the effect of interactive computer simulations or science textbook assignments on the nature and quality of postgraduate…

  5. Nature of Teacher-Students' Interaction in Electronic Learning and Traditional Courses of Higher Education--A Review

    ERIC Educational Resources Information Center

    Malik, Sufiana Khatoon; Khurshed, Fauzia

    2011-01-01

    Present paper explores differential teacher-student interaction in electronic learning (el) and in face to face traditional learning (tl) courses at higher education. After thorough study literature available and getting information from university teachers teaching el and tl courses about the nature of teacher-students interaction in both modes…

  6. Rethinking Theoretical Approaches to Stigma

    PubMed Central

    Martin, Jack K; Lang, Annie; Olafsdottir, Sigrun

    2008-01-01

    A resurgence of research and policy efforts on stigma both facilitates and forces a reconsideration of the levels and types of factors that shape reactions to persons with conditions that engender prejudice and discrimination. Focusing on the case of mental illness but drawing from theories and studies of stigma across the social sciences, we propose a framework that brings together theoretical insights from micro, meso and macro level research: Framework Integrating Normative Influences on Stigma (FINIS) starts with Goffman’s notion that understanding stigma requires a language of social relationships, but acknowledges that individuals do not come to social interaction devoid of affect and motivation. Further, all social interactions take place in a context in which organizations, media and larger cultures structure normative expectations which create the possibility of marking “difference”. Labelling theory, social network theory, the limited capacity model of media influence, the social psychology of prejudice and discrimination, and theories of the welfare state all contribute to an understanding of the complex web of expectations shaping stigma. FINIS offers the potential to build a broad-based scientific foundation based on understanding the effects of stigma on the lives of persons with mental illness, the resources devoted to the organizations and families who care for them, and policies and programs designed to combat stigma. We end by discussing the clear implications this framework holds for stigma reduction, even in the face of conflicting results. PMID:18436358

  7. Folding of the natural hammerhead ribozyme is enhanced by interaction of auxiliary elements

    PubMed Central

    PENEDO, J. CARLOS; WILSON, TIMOTHY J.; JAYASENA, SUMEDHA D.; KHVOROVA, ANASTASIA; LILLEY, DAVID M.J.

    2004-01-01

    It has been shown that the activity of the hammerhead ribozyme at μM magnesium ion concentrations is markedly increased by the inclusion of loops in helices I and II. We have studied the effect of such loops on the magnesium ion-induced folding of the ribozyme, using fluorescence resonance energy transfer. We find that with the loops in place, folding into the active conformation occurs in a single step, in the μM range of magnesium ion concentration. Disruption of the loop–loop interaction leads to a reversion to two-step folding, with the second stage requiring mM concentrations of magnesium ion. Sodium ions also promote the folding of the natural form of the ribozyme at high concentrations, but the folding occurs as a two-stage process. The loops clearly act as important auxiliary elements in the function of the ribozyme, permitting folding to occur efficiently under physiological conditions. PMID:15100442

  8. Trace metal interactions with microbial biofilms in natural and engineered systems

    SciTech Connect

    Lion, L.W.; Shuler, M.L.; Hsieh, K.M.; Ghiorse, W.C. )

    1988-01-01

    Trace metal adsorption and desorption are important processes in natural aquatic systems and in designed treatment systems. Adsorption of metals onto particulate matter and humic substances has been documented in fresh water and marine systems. Although biofilms coating surfaces are well documented, the chemical mechanisms concerning metal removal have not been investigated thoroughly. Biofilms consist predominantly of bacterial cells enmeshed in a network of negatively charged extracellular polymers. The biofilms are assumed to contain ferromanganese deposits which can play an important role in trace metal absorption. Microorganisms have developed resistance to metal toxicity, especially since the Industrial Revolution. Detoxification mechanisms include biomethylation, biosynthesis of intracellular traps, cellular efflux, synthesis of chelating agents, and surface precipitation. Mathematical models have been developed to describe various aspects of trace metal interaction with surfaces: (1) cellular growth, attachment, and polymer production; (2) metal binding to inorganic surfaces; (3) metal binding to cellular surfaces; and (4) biofilm model integrated with a metal-binding model.

  9. Effect of nature of oxygen interactions on friction of titanium, aluminum, and molybdenum

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1976-01-01

    Friction studies were conducted with a gold pin contacting titanium, aluminum, and molybdenum surfaces after exposure to oxygen with various methods. Oxygen was adsorbed on the surface, it reacted with the surface, and the surface was ion bombarded with oxygen. The presence of oxygen was monitored with Auger spectroscopy. Titanium friction varied with the mode of the metal-oxygen interaction. It was highest with the adsorbed oxygen and least with ion bombardment using oxygen. Aluminum exhibited lower friction values for the reacted and the ion bombarded surfaces than for the surface having the adsorbed layer. With molybdenum the friction coefficients were generally the same despite the nature of the surface treatment with oxygen.

  10. Denosumab mimics the natural decoy receptor osteoprotegerin by interacting with its major binding site on RANKL.

    PubMed

    Schieferdecker, Aneta; Voigt, Mareike; Riecken, Kristoffer; Braig, Friederike; Schinke, Thorsten; Loges, Sonja; Bokemeyer, Carsten; Fehse, Boris; Binder, Mascha

    2014-08-30

    Bone homeostasis critically relies on the RANKL-RANK-OPG axis which can be targeted by the fully human monoclonal antibody denosumab in conditions with increased bone resporption such as bone metastases. The binding site and therefore the molecular mechanism by which this antibody inhibits RANKL has not been characterized so far. Here, we used random peptide phage display library screenings to identify the denosumab epitope on RANKL. Alignments of phage derived peptide sequences with RANKL suggested that this antibody recognized a linear epitope between position T233 and Y241. Mutational analysis confirmed the core residues as critical for this interaction. The spatial localization of this epitope on a 3-dimensional model of RANKL showed that it overlapped with the major binding sites of OPG and RANK on RANKL. We conclude that denosumab inhibits RANKL by both functional and molecular mimicry of the natural decoy receptor OPG.

  11. [Characteristics of Natural Selection in Populations of Nodule Bacteria (Rhizobium leguminosarum) Interacting With Different Host Plants].

    PubMed

    Andronov, E E; Igolkina, A A; Kimeklis, A K; Vorobyov, N I; Provorov, N A

    2015-10-01

    Using high throughput sequencing of the nodA gene, we studied the population dynamics of Rhizobium leguminosarum (bv. viciae, bv. trifolii) in rhizospheric and nodular subpopulations associated with the leguminous plants representing different cross-inoculation groups (Vicia sativa, Lathyrus pratensis of the vetch/vetchling/pea group and Trifolium hybridum of the clover group). The "rhizosphere-nodules" transitions result in either an increase or decrease in the frequencies of 10 of the 23 operational taxonomic units (OTUs) (which were identified with 95% similarity) depending on the symbiotic specificity and phylogenetic positions of OTUs. Statistical and bioinformatical analysis of the population structures suggest that the type of natural selection responsible for these changes may be diversifying at the whole-population level and frequency-dependent at the OTU-specific level, ensuring the divergent evolution of rhizobia interacting with different host species.

  12. Evolution of non-interacting entropic dark energy and its phantom nature

    NASA Astrophysics Data System (ADS)

    Mathew, Titus K.; Murali, Chinthak; Shejeelammal, J.

    2016-04-01

    Assuming the form of the entropic dark energy (EDE) as it arises from the surface term in the Einstein-Hilbert’s action, its evolution was analyzed in an expanding flat universe. The model parameters were evaluated by constraining the model using the Union data on Type Ia supernovae. We found that in the non-interacting case, the model predicts an early decelerated phase and a later accelerated phase at the background level. The evolutions of the Hubble parameter, dark energy (DE) density, equation of state parameter and deceleration parameter were obtained. The model hardly seems to be supporting the linear perturbation growth for the structure formation. We also found that the EDE shows phantom nature for redshifts z < 0.257. During the phantom epoch, the model predicts big rip effect at which both the scale factor of expansion and the DE density become infinitely large and the big rip time is found to be around 36 Giga years from now.

  13. Rethinking Global Water Governance for the 21st Century

    NASA Astrophysics Data System (ADS)

    Ajami, N. K.; Cooley, H.

    2012-12-01

    Growing pressure on the world's water resources is having major impacts on our social and economic well-being. According to the United Nations, today, at least 1.1 billion people do not have access to clean drinking water. Pressures on water resources are likely to continue to worsen in response to decaying and crumbling infrastructure, continued population growth, climate change, degradation of water quality, and other challenges. If these challenges are not addressed, they pose future risks for many countries around the world, making it urgent that efforts are made to understand both the nature of the problems and the possible solutions that can effectively reduce the associated risks. There is growing understanding of the need to rethink governance to meet the 21st century water challenges. More and more water problems extend over traditional national boundaries and to the global community and the types and numbers of organizations addressing water issues are large and growing. Economic globalization and transnational organizations and activities point to the need for improving coordination and integration on addressing water issues, which are increasingly tied to food and energy security, trade, global climate change, and other international policies. We will present some of the key limitations of global water governance institutions and provide recommendations for improving these institutions to address 21st century global water challenges more effectively.

  14. Rethinking intractable conflict: the perspective of dynamical systems.

    PubMed

    Vallacher, Robin R; Coleman, Peter T; Nowak, Andrzej; Bui-Wrzosinska, Lan

    2010-01-01

    Intractable conflicts are demoralizing. Beyond destabilizing the families, communities, or international regions in which they occur, they tend to perpetuate the very conditions of misery and hate that contributed to them in the first place. Although the common factors and processes associated with intractable conflicts have been identified through research, they represent an embarrassment of riches for theory construction. Thus, the current task in this area is integrating these diverse factors into an account that provides a coherent perspective yet allows for prediction and a basis for conflict resolution in specific conflict settings. We suggest that the perspective of dynamical systems provides such an account. This article outlines the key concepts and hypotheses associated with this approach. It is organized around a set of basic questions concerning intractable conflict for which the dynamical perspective offers fresh insight and testable propositions. The questions and answers are intended to provide readers with basic concepts and principles of complexity and dynamical systems that are useful for rethinking the nature of intractable conflict and the means by which such conflict can be transformed.

  15. Prediction of barrier island restoration response and its interactions with the natural environment

    NASA Astrophysics Data System (ADS)

    Plant, N. G.; Stockdon, H. F.; Flocks, J.; Sallenger, A. H.; Long, J. W.; Cormier, J. M.; Guy, K.; Thompson, D. M.

    2012-12-01

    A 2-meter high sand berm was constructed along Chandeleur Island, Louisiana, in an attempt to provide protection against the Deepwater Horizon oil spill. Berm construction started in June 2010 and ended in April 2011. Variations in both island morphology and construction of the 15-km long berm resulted in the development of four different morphologies: a berm built on a submerged island platform to the north of the existing island, a berm built seaward of the existing island, a berm built along the island shoreline, and portions of the island where no berm was constructed. These different morphologies provide a natural laboratory for testing the understanding of berm and barrier island response to storms. In particular, the ability to predict berm evolution using statistical modeling of the interactions between the island, berm, and oceanographic processes was tested. This particular test was part of a broader USGS research effort to understand processes that bridge the gap between short-term storm response and longer-term geologic and climate interactions that shape barrier-island systems. Berm construction and subsequent berm and island evolution were monitored using satellite and aerial remote sensing and topographic and bathymetric surveys. To date, significant berm evolution occurred in both the north (including terminal erosion, overwash, and a large breach), center (overwash and numerous breaches), and south (overwash). The response of the central portion of the berm to winter and tropical storms was significant such that none of the residual berm remained within its construction footprint. The evolution of the central portion of the berm was well predicted using a statistical modeling approach that used predicted and modeled wave conditions to identify the likelihood of overwash events. Comparison of different modeled evolution scenarios to the one that was observed showed that berm response was sensitive to the frequency and severity of winter and tropical

  16. Interactions among wildland fires in a long-established Sierra Nevada natural fire area

    USGS Publications Warehouse

    Collins, B.M.; Miller, J.D.; Thode, A.E.; Kelly, M.; van Wagtendonk, J.W.; Stephens, S.L.

    2009-01-01

    We investigate interactions between successive naturally occurring fires, and assess to what extent the environments in which fires burn influence these interactions. Using mapped fire perimeters and satellite-based estimates of post-fire effects (referred to hereafter as fire severity) for 19 fires burning relatively freely over a 31-year period, we demonstrate that fire as a landscape process can exhibit self-limiting characteristics in an upper elevation Sierra Nevada mixed conifer forest. We use the term 'self-limiting' to refer to recurring fire as a process over time (that is, fire regime) consuming fuel and ultimately constraining the spatial extent and lessening fire-induced effects of subsequent fires. When the amount of time between successive adjacent fires is under 9 years, and when fire weather is not extreme (burning index <34.9), the probability of the latter fire burning into the previous fire area is extremely low. Analysis of fire severity data by 10-year periods revealed a fair degree of stability in the proportion of area burned among fire severity classes (unchanged, low, moderate, high). This is in contrast to a recent study demonstrating increasing high-severity burning throughout the Sierra Nevada from 1984 to 2006, which suggests freely burning fires over time in upper elevation Sierra Nevada mixed conifer forests can regulate fire-induced effects across the landscape. This information can help managers better anticipate short- and long-term effects of allowing naturally ignited fires to burn, and ultimately, improve their ability to implement Wildland Fire Use programs in similar forest types. ?? 2008 Springer Science+Business Media, LLC.

  17. Uncertainty of natural tracer methods for quantifying river-aquifer interaction in a large river

    NASA Astrophysics Data System (ADS)

    Xie, Yueqing; Cook, Peter G.; Shanafield, Margaret; Simmons, Craig T.; Zheng, Chunmiao

    2016-04-01

    The quantification of river-aquifer interaction is critical to the conjunctive management of surface water and groundwater, in particular in the arid and semiarid environment with much higher potential evapotranspiration than precipitation. A variety of natural tracer methods are available to quantify river-aquifer interaction at different scales. These methods however have only been tested in rivers with relatively low flow rates (mostly less than 5 m3 s-1). In this study, several natural tracers including heat, radon-222 and electrical conductivity were measured both on vertical riverbed profiles and on longitudinal river samples to quantify river-aquifer exchange flux at both point and regional scales in the Heihe River (northwest China; flow rate 63 m3 s-1). Results show that the radon-222 profile method can estimate a narrower range of point-scale flux than the temperature profile method. In particular, three vertical radon-222 profiles failed to estimate the upper bounds of plausible flux ranges. Results also show that when quantifying regional-scale river-aquifer exchange flux, the river chemistry method constrained the flux (5.20-10.39 m2 d-1) better than the river temperature method (-100 to 100 m2 d-1). The river chemistry method also identified spatial variability of flux, whereas the river temperature method did not have sufficient resolution. Overall, for quantifying river-aquifer exchange flux in a large river, both the temperature profile method and the radon-222 profile method provide useful complementary information at the point scale to complement each other, whereas the river chemistry method is recommended over the river temperature method at the regional scale.

  18. Rethinking "posterior" tongue-tie.

    PubMed

    Douglas, Pamela Sylvia

    2013-12-01

    Currently, many clinicians who help with breastfeeding problems are diagnosing "posterior" tongue-tie in infants and performing or referring for frenotomy. In this "Speaking Out" article, I argue that the diagnosis of "posterior" tongue-tie has successfully raised awareness of the importance of impaired tongue function in breastfeeding difficulty. However, the diagnosis of "posterior" tongue-tie also applies a reductionist, medicalized theoretical frame to the complex problem of impaired tongue function, risking unintended outcomes. Impaired tongue function arises out of multiple interacting and co-evolving factors, including the interplay between social behaviors concerning breastfeeding and mother-infant biology. Consideration of theoretical frames is vital if we are to build an evidence base through efficient use of the scarce resources available for clinical breastfeeding research and minimize unintended outcomes.

  19. Mimicking bubble use in nature: propulsion of Janus particles due to hydrophobic-hydrophilic interactions.

    PubMed

    Pinchasik, Bat-El; Möhwald, Helmuth; Skirtach, Andre G

    2014-07-09

    Bubbles are widely used by animals in nature in order to fulfill important functions. They are used by animals in order to walk underwater or to stabilize themselves at the water/air interface. The main aim of this work is to imitate such phenomena, which is the essence of biomimetics. Here, bubbles are used to propel and to control the location of Janus particles in an aqueous medium. The synthesis of Janus SiO2-Ag and polystyrene-Ag (PS-Ag) particles through embedment in Parafilm is presented. The Janus particles, partially covered with catalytically active Ag nanoparticles, are redispersed in water and placed on a glass substrate. The active Ag sites are used for the splitting of H2O2 into water and oxygen. As a result, an oxygen bubble is formed on one side of the particle and promotes its propulsion. Once formed, the bubble-particle complex is stable and therefore, can be manipulated by tuning hydrophilic-hydrophobic interactions with the surface. In this way a transition between two- and three- dimensional motion is possible by changing the hydrophobicity of the substrate. Similar principles are used in nature.

  20. Host-parasite genetic interactions and virulence-transmission relationships in natural populations of monarch butterflies.

    PubMed

    de Roode, Jacobus C; Altizer, Sonia

    2010-02-01

    Evolutionary models predict that parasite virulence (parasite-induced host mortality) can evolve as a consequence of natural selection operating on between-host parasite transmission. Two major assumptions are that virulence and transmission are genetically related and that the relative virulence and transmission of parasite genotypes remain similar across host genotypes. We conducted a cross-infection experiment using monarch butterflies and their protozoan parasites from two populations in eastern and western North America. We tested each of 10 host family lines against each of 18 parasite genotypes and measured virulence (host life span) and parasite transmission potential (spore load). Consistent with virulence evolution theory, we found a positive relationship between virulence and transmission across parasite genotypes. However, the absolute values of virulence and transmission differed among host family lines, as did the rank order of parasite clones along the virulence-transmission relationship. Population-level analyses showed that parasites from western North America caused higher infection levels and virulence, but there was no evidence of local adaptation of parasites on sympatric hosts. Collectively, our results suggest that host genotypes can affect the strength and direction of selection on virulence in natural populations, and that predicting virulence evolution may require building genotype-specific interactions into simpler trade-off models.

  1. HAZPAC; an interactive map of Pacific Rim natural hazards, population, and infrastructure

    USGS Publications Warehouse

    Bemis, B.L.; Goss, H.V.; Yurkovich, E.S.; Perron, T.J.; Howell, D.G.

    2002-01-01

    This is an online version of a CD-ROM publication. The text files that describe using this publication make reference to software provided on the disc. For this online version the software can be downloaded for free from Adobe Systems and Environmental Systems Research Institute, Inc. (ESRI). Welcome to HAZPAC! HAZPAC is an interactive map about natural hazard risk in the Pacific Rim region. It is intended to communicate to a broad audience the ideas of 'Crowding the Rim,' which is an international, public-private partnership that fosters collaborative solutions for regional risks. HAZPAC, which stands for 'HAZards of the PACific,' uses Geographic Information System (GIS) technology to help people visualize the socioeconomic connections and shared hazard vulnerabilities among Pacific Rim countries, as well as to explore the general nature of risk. Please refer to the 'INTRODUCTION TO HAZPAC' section of the readme file below to determine which HAZPAC project will be right for you. Once you have decided which HAZPAC project is suitable for you, please refer to the 'GETTING STARTED' sections in the readme file for some basic information that will help you begin using HAZPAC. Also, we highly recommend that you follow the Tutorial exercises in the project-specific HAZPAC User Guides. The User Guides are PDF (Portable Document Format) files that must be read with Adobe Acrobat Reader (a free copy of Acrobat Reader is available using the link near the bottom of this page).

  2. Combining Natural Sequence Variation with High Throughput Mutational Data to Reveal Protein Interaction Sites

    PubMed Central

    Melamed, Daniel; Young, David L.; Miller, Christina R.; Fields, Stanley

    2015-01-01

    Many protein interactions are conserved among organisms despite changes in the amino acid sequences that comprise their contact sites, a property that has been used to infer the location of these sites from protein homology. In an inter-species complementation experiment, a sequence present in a homologue is substituted into a protein and tested for its ability to support function. Therefore, substitutions that inhibit function can identify interaction sites that changed over evolution. However, most of the sequence differences within a protein family remain unexplored because of the small-scale nature of these complementation approaches. Here we use existing high throughput mutational data on the in vivo function of the RRM2 domain of the Saccharomyces cerevisiae poly(A)-binding protein, Pab1, to analyze its sites of interaction. Of 197 single amino acid differences in 52 Pab1 homologues, 17 reduce the function of Pab1 when substituted into the yeast protein. The majority of these deleterious mutations interfere with the binding of the RRM2 domain to eIF4G1 and eIF4G2, isoforms of a translation initiation factor. A large-scale mutational analysis of the RRM2 domain in a two-hybrid assay for eIF4G1 binding supports these findings and identifies peripheral residues that make a smaller contribution to eIF4G1 binding. Three single amino acid substitutions in yeast Pab1 corresponding to residues from the human orthologue are deleterious and eliminate binding to the yeast eIF4G isoforms. We create a triple mutant that carries these substitutions and other humanizing substitutions that collectively support a switch in binding specificity of RRM2 from the yeast eIF4G1 to its human orthologue. Finally, we map other deleterious substitutions in Pab1 to inter-domain (RRM2–RRM1) or protein-RNA (RRM2–poly(A)) interaction sites. Thus, the combined approach of large-scale mutational data and evolutionary conservation can be used to characterize interaction sites at single

  3. Risk dynamics: unraveling the role of socio-techno-nature interactions

    NASA Astrophysics Data System (ADS)

    Di Baldassarre, G.; Viglione, A.; Carr, G.; Kuil, L., Jr.; Brandimarte, L.; Yan, K.; Bloeschl, G.

    2015-12-01

    In disaster risk reduction, there is still a lack of methods capturing the dynamics of risk emerging from the complex interplay between physical and social processes. Two examples of these dynamics are the learning and levee effects. The learning effect is about the empirical evidence that more frequent hazardous events are often associated with decreasing societal vulnerability, e.g. human adaptation. The levee effect is about the stylized fact (discussed already by White in the 1940s) that less frequent hazardous events (sometimes paradoxically due to the implementation of risk prevention structures, such as levees) often lead to increasing societal vulnerability. We posit that current projections of future flood risk are not realistic because most analytical frameworks do not capture the aforementioned dynamics. Then, we propose an interdisciplinary approach whereby two-way interactions and feedbacks between social and physical processes are explicitly accounted for (Di Baldassarre et al., 2014; 2015). Here we show an application of this approach with a focus on flood risk changes, and demonstrate its capability to capture and explain the dynamics emerging from socio-techno-nature interactions. Lastly, the potentials and limitations of the proposed approach to assess risk dynamics in a rapidly changing environment are critically discussed.

  4. Time Lapse Spectropolarimetry: Constraining the Nature and Progenitors of Interacting CCSNe

    NASA Astrophysics Data System (ADS)

    Huk, Leah N.; SNSPOL

    2017-01-01

    SNe Type IIn are among the brightest supernova explosions due to strong circumstellar interaction, but the category is not well defined. The heterogeneous nature of the class implies that any number of different progenitors can give rise to a IIn event so long as there is appreciable mass loss prior to explosion. Examining the geometric and optical properties of the circumstellar material (CSM) can help to identify the progenitors of individual IIn SNe. Polarimetry is the optimal method for constraining CSM characteristics as polarimetric signals depend on and preserve geometric information from unresolved sources.I present results of an ensemble of three-dimensional simulations of the polarized H alpha emission-line profiles of interacting SNe using a Monte Carlo radiative transfer code called SLIP. A novel feature of these simulations is their ability to emit photons from a distributed shock region as well as from a central source. This allows us to investigate two different illumination scenarios as well as CSM properties. We present results for how these different models best match multi-epoch observed polarized spectra of the IIn SNe 1997eg, and all IIn from the the SNSPOL collaboration database. I will use the results to investigate relationships among SNe IIn based on viewing angle and consider whether the IIn category should be subdivided based on physical properties of the CSM and/or progenitor.

  5. Motions and electrostatic interactions in natural and semisynthetic myoglobins: a carbon-13 nuclear magnetic resonance study

    SciTech Connect

    Maskalick, D.G.

    1984-01-01

    It is expected that the internal motions of amino acid side chains and protein backbone segments influence and are in turn affected by charge-charge and related interactions, steric constraints, hydrophobic forces, and hydrogen bonding. As an initial test of this theory /sup 13/C-enriched glycine, alanine, and isoleucine have been substituted for the amino terminal valine of sperm whale myoglobin using semisynthetic techniques. /sup 13/C-NMR has been used to analyze the motions of the side chain and the protonation state of the alpha amino group as a function of pH. The addition of a single methyl group to the side chain can alter the alpha amino pK value by as much as 0.3 pH units indicating a delicately balanced set of change-charge interactions between the alpha amino group and the rest of the protein. Further evidence in support of the state theory was found upon examination of the internal motions of seven of nine isoleucine vectors. These motions were extracted from natural abundance /sup 13/C-NMR relaxation data. The results suggest a strong possibility that concerted motions are important. Also, an increase in temperature from 32/sup 0/C to 52/sup 0/C leads to an electrostatically driven tightening of the myoglobin structure as evidenced by no significant increase in motion amplitude of most of the vectors.

  6. Extraction of CYP chemical interactions from biomedical literature using natural language processing methods.

    PubMed

    Jiao, Dazhi; Wild, David J

    2009-02-01

    This paper proposes a system that automatically extracts CYP protein and chemical interactions from journal article abstracts, using natural language processing (NLP) and text mining methods. In our system, we employ a maximum entropy based learning method, using results from syntactic, semantic, and lexical analysis of texts. We first present our system architecture and then discuss the data set for training our machine learning based models and the methods in building components in our system, such as part of speech (POS) tagging, Named Entity Recognition (NER), dependency parsing, and relation extraction. An evaluation of the system is conducted at the end, yielding very promising results: The POS, dependency parsing, and NER components in our system have achieved a very high level of accuracy as measured by precision, ranging from 85.9% to 98.5%, and the precision and the recall of the interaction extraction component are 76.0% and 82.6%, and for the overall system are 68.4% and 72.2%, respectively.

  7. Nature of the Surface-Exposed Cytochrome-Electrode Interactions in Electroactive Biofilms of Desulfuromonas acetoxidans.

    PubMed

    Alves, A; Ly, H K; Hildebrandt, P; Louro, R O; Millo, D

    2015-06-25

    Metal-respiring bacteria are microorganisms capable of oxidizing organic pollutants present in wastewater and transferring the liberated electrons to an electrode. This ability has led to their application as catalysts in bioelectrochemical systems (BESs), a sustainable technology coupling bioremediation to electricity production. Crucial for the functioning of these BESs is a complex protein architecture consisting of several surface-exposed multiheme proteins, called outer membrane cytochromes, wiring the cell metabolism to the electrode. Although the role of these proteins has been increasingly understood, little is known about the protein-electrode interactions and their impact on the performance of BESs. In this study, we used surface-enhanced resonance Raman spectroscopy in combination with electrochemical techniques to unravel the nature of the protein-electrode interaction for the outer membrane cytochrome OmcB from Desulfuromonas acetoxidans (Dace). Comparing the spectroelectrochemical properties of OmcB bound directly to the electrode surface with those of the same protein embedded inside an electroactive biofilm, we have shown that the surface-exposed cytochromes of Dace biofilms are in direct contact with the electrode surface. Even if direct binding causes protein denaturation, the biofilm possesses the ability to minimize the extent of the damage maximizing the amount of cells in direct electrical communication with the electrode.

  8. Nature of the interactions between hypocrealean fungi and the mutualistic fungus of leaf-cutter ants.

    PubMed

    Varanda-Haifig, Sadala Schmidt; Albarici, Tatiane Regina; Nunes, Pablo Henrique; Haifig, Ives; Vieira, Paulo Cezar; Rodrigues, Andre

    2017-04-01

    Leaf-cutter ants cultivate and feed on the mutualistic fungus, Leucoagaricus gongylophorus, which is threatened by parasitic fungi of the genus Escovopsis. The mechanism of Escovopsis parasitism is poorly understood. Here, we assessed the nature of the antagonism of different Escovopsis species against its host. We also evaluated the potential antagonism of Escovopsioides, a recently described fungal genus from the attine ant environment whose role in the colonies of these insects is unknown. We performed dual-culture assays to assess the interactions between L. gongylophorus and both fungi. We also evaluated the antifungal activity of compounds secreted by the latter on L. gongylophorus growth using crude extracts of Escovopsis spp. and Escovopsioides nivea obtained either in (1) absence or (2) presence of the mutualistic fungus. The physical interaction between these fungi and the mutualistic fungus was examined under scanning electron microscopy (SEM). Escovopsis spp. and E. nivea negatively affected the growth of L. gongylophorus, which was also significantly inhibited by both types of crude extract. These results indicate that Escovopsis spp. and E. nivea produce antifungal metabolites against the mutualistic fungus. SEM showed that Escovopsis spp. and E. nivea maintained physical contact with the mutualistic fungus, though no specialised structures related to mycoparasitism were observed. These results showed that Escovopsis is a destructive mycoparasite that needs physical contact for the death of the mutualistic fungus to occur. Also, our findings suggest that E. nivea is an antagonist of the ant fungal cultivar.

  9. [Interactions between natural vegetation succession and waste residue in lead-zinc tailings deposited sites].

    PubMed

    Liu, Hong-yan; Xing, Dan; Xlao, Jiu-jun; Liu, Fang

    2010-12-01

    Natural vegetation succession process and related mechanism is one of the important research contents in ecological restoration of abandoned mining land. Taking 4 lead-zinc tailings deposited sites with the recovery time being about 10 years, 20 years, 30 year, and over 40 years under similar site conditions in northwest Guizhou Provinnce as study areas, this paper studied the interactions between the natural vegetation succession and the physicochemical properties of waste residue. The results showed that with the increasing dumping time of the waste residue, the nutritional conditions of base material improved significantly, the total N, P, and K contents and the pH value increased, while the EC, bulk density, and especially, available lead and cadmium contents decreased. Meanwhile, the plant community species richness (S), diversity index (H), and evenness (J) increased correspondingly with increasing recovery time. The composition of plant communities was dominated by perennial herbaceous. In the first 20 years of recovery, the vegetation succession process was very slow, but after 30- and 40-year recovery, the vegetation coverage reached 53% and 87%, respectively. Canonical correlation analysis showed that there were significant correlations between base material properties and species diversity, and the canonical variables were the total N, P, and K contents of base material. The species diversity index was significantly negatively correlated with the available Pb and Cd contents of base material. The natural vegetation succession process in the study areas accelerated after 30 years of recovery, and the limiting factors of vegetation recovery were the nutrient deficiency and the high availability of Pb and Cd in base material.

  10. Perceiving referential intent: Dynamics of reference in natural parent-child interactions.

    PubMed

    Trueswell, John C; Lin, Yi; Armstrong, Benjamin; Cartmill, Erica A; Goldin-Meadow, Susan; Gleitman, Lila R

    2016-03-01

    Two studies are presented which examined the temporal dynamics of the social-attentive behaviors that co-occur with referent identification during natural parent-child interactions in the home. Study 1 focused on 6.2 h of videos of 56 parents interacting during everyday activities with their 14-18 month-olds, during which parents uttered common nouns as parts of spontaneously occurring utterances. Trained coders recorded, on a second-by-second basis, parent and child attentional behaviors relevant to reference in the period (40 s) immediately surrounding parental naming. The referential transparency of each interaction was independently assessed by having naïve adult participants guess what word the parent had uttered in these video segments, but with the audio turned off, forcing them to use only non-linguistic evidence available in the ongoing stream of events. We found a great deal of ambiguity in the input along with a few potent moments of word-referent transparency; these transparent moments have a particular temporal signature with respect to parent and child attentive behavior: it was the object's appearance and/or the fact that it captured parent/child attention at the moment the word was uttered, not the presence of the object throughout the video, that predicted observers' accuracy. Study 2 experimentally investigated the precision of the timing relation, and whether it has an effect on observer accuracy, by disrupting the timing between when the word was uttered and the behaviors present in the videos as they were originally recorded. Disrupting timing by only ±1 to 2 s reduced participant confidence and significantly decreased their accuracy in word identification. The results enhance an expanding literature on how dyadic attentional factors can influence early vocabulary growth. By hypothesis, this kind of time-sensitive data-selection process operates as a filter on input, removing many extraneous and ill-supported word-meaning hypotheses from

  11. Rethinking Actions: Implementation and Association

    PubMed Central

    Chatterjee, Anjan

    2015-01-01

    Action processing allows us to move through and interact with the world, as well as understand the movements performed by other people. In recent years, there has been increasing interest in the semantics of actions as differentiated from the semantics of objects. However, as the understanding of action semantics has evolved, it is evident that the existing literature conflates two senses of the word “action”—one that stems from studies of tool use and the other from event representation. In this paper, we suggest that this issue can be clarified by closely examining differences in how the human parietal and temporal cortices of the brain process action-related stimuli. By contrasting the posterior parietal cortex to the posterolateral temporal cortex, we characterize two complementary action systems in the human brain, each with its own specialization of function. We suggest that these two systems be referred to as the parietal Action Implementation System, and the posterolateral temporal Action Association System. While the fronto-parietal system is concerned primarily with how we perform actions, and simulate others’ actions, the temporal action system is more involved with processing actions from a third-person, conceptual standpoint. Recent work in cognitive neuroscience of perception and language, as well as the neuroanatomical organization of these brain regions support this distinction. We will discuss the implications of this work for cognition-, language-, and neuroscience-based action research. PMID:26352170

  12. Biology, childhood trauma, and murder: rethinking justice.

    PubMed

    Heide, Kathleen M; Solomon, Eldra P

    2006-01-01

    This article reviews recent findings in the developmental neurophysiology of children subjected to psychological trauma. Studies link extreme neglect and abuse with long-term changes in the nervous and endocrine systems. A growing body of research literature indicates that individuals with severe trauma histories are at higher risk of behaving violently than those without such histories. This article links these two research areas by discussing how severe and protracted child abuse and/or neglect can lead to biological changes, putting these individuals at greater risk for committing homicide and other forms of violence than those without child maltreatment histories. The implications of these biological findings for forensic evaluations are discussed. Based on new understanding of the effects of child maltreatment, the authors invite law and mental health professionals to rethink their notions of justice and offender accountability, and they challenge policymakers to allocate funds for research into effective treatment and for service delivery.

  13. Rethinking the Buy vs. Lease Decision

    DTIC Science & Technology

    2014-04-30

    mêçÖê~ãW= `êÉ~íáåÖ=póåÉêÖó=Ñçê=fåÑçêãÉÇ=`Ü~åÖÉ= - 23 - The United Kingdom approved a similar plan to lease tankers via a private finance initiative...bäÉîÉåíÜ=^ååì~ä=^Åèìáëáíáçå= oÉëÉ~êÅÜ=póãéçëáìã= qÜìêëÇ~ó=pÉëëáçåë= sçäìãÉ=ff= = Rethinking the Buy vs. Lease Decision Jacques Gansler, University...Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302

  14. Illustrating the Interaction of Nature and People in Ecosystem Services: The Case of Terroir in Wine

    NASA Astrophysics Data System (ADS)

    Nicholas, K. A.

    2014-12-01

    The ecosystem services (ES) approach is increasingly used in research and policy, with the Common International Framework on Ecosystem Services (CICES) "cascade" gaining traction as a framework for conceptualizing the production of ecosystem services by the natural environment, and then people consuming these services and obtaining benefits depending on their values. However, uptake of the ES concept on the ground by ecosystem managers, and understanding by everyday citizens, is still limited. One barrier is the challenge of providing tangible, examples of everyday benefits and values that people can readily connect with the biophysical structures and functions that underlie their provision. Winegrowing offers one promising case to illustrate the linkages all along the chain of production and consumption of ecosystem services. The sensitive winegrape has long been known for its properties of terroir, where the taste of wine reflects the environmental conditions of the place where it is grown, a feature valued by consumers. Here the CICES framework is illustrated with the case of winegrowing, demonstrating that the current linear model of natural production and human consumption of ES needs to be modified for this case because people influence each of the five stages by shaping and responding to their environment, producing a two-way interaction between people and the environment throughout. For example, while natural drivers such as climate and soils are key to the provision of the service of winegrape yields, landowners modify the biophysical environment through site selection and growers modify plant ecophysiological function through farming practices such as pruning and irrigation in order to influence the final service. Similarly, winemakers' expertise is needed to transform the service of winegrape yields into the product of wine that can be enjoyed and valued by consumers, whose preferences shape wine styles as well. This case illustrates how incorporating

  15. Rethinking Black Hole Accretion Discs

    NASA Astrophysics Data System (ADS)

    Salvesen, Greg

    Accretion discs are staples of astrophysics. Tapping into the gravitational potential energy of the accreting material, these discs are highly efficient machines that produce copious radiation and extreme outflows. While interesting in their own right, accretion discs also act as tools to study black holes and directly influence the properties of the Universe. Black hole X-ray binaries are fantastic natural laboratories for studying accretion disc physics and black hole phenomena. Among many of the curious behaviors exhibited by these systems are black hole state transitions -- complicated cycles of dramatic brightening and dimming. Using X-ray observations with high temporal cadence, we show that the evolution of the accretion disc spectrum during black hole state transitions can be described by a variable disc atmospheric structure without invoking a radially truncated disc geometry. The accretion disc spectrum can be a powerful diagnostic for measuring black hole spin if the effects of the disc atmosphere on the emergent spectrum are well-understood; however, properties of the disc atmosphere are largely unconstrained. Using statistical methods, we decompose this black hole spin measurement technique and show that modest uncertainties regarding the disc atmosphere can lead to erroneous spin measurements. The vertical structure of the disc is difficult to constrain due to our ignorance of the contribution to hydrostatic balance by magnetic fields, which are fundamental to the accretion process. Observations of black hole X-ray binaries and the accretion environments near supermassive black holes provide mounting evidence for strong magnetization. Performing numerical simulations of accretion discs in the shearing box approximation, we impose a net vertical magnetic flux that allows us to effectively control the level of disc magnetization. We study how dynamo activity and the properties of turbulence driven by the magnetorotational instability depend on the

  16. Son of SPECOPS: Rethinking the Nature and Operationalization of Cyberspace

    DTIC Science & Technology

    2012-04-27

    nano-satellites,” which have dimensions similar to a loaf of bread , hover in low earth orbit (LEO), and broadcast data directly to fielded SOF...consequences, as the 1993 “ Black Hawk Down” incident illustrates. It was, after all, the fallout from this tragic episode that influenced the decision not...personality types, regardless of intelligence, can be molded to conduct effective operations in the cyber domain. This axiom also applies to the

  17. Re/Thinking the Nature of Technology in Science Classrooms

    ERIC Educational Resources Information Center

    Kim, Mijung; Roth, Wolff-Michael

    2016-01-01

    With increasing technological changes and needs in society, technology and engineering education has received much attention in school science. Yet, technology traditionally has been subordinated to science or simply taken as the application of science. This position has resulted in a limited understanding of teaching technological and engineering…

  18. Natural vs synthetic auxin: studies on the interactions between plant hormones and biological membrane lipids.

    PubMed

    Flasiński, Michał; Hąc-Wydro, Katarzyna

    2014-08-01

    Analysis of the interactions between two representatives of plant hormones: synthetic (1-naphthaleneacetic acid, NAA) as well as natural (indole-3-acetic acid, IAA) and phospholipids occurring in biological membrane of both plant and animal cells was the subject of present studies. The aim of undertaken experiments was to elucidate the problem of direct influence of these plant growth regulators on phosphatidylcholines (PCs) and phosphatidylethanolamines (PEs) in monolayers at the air/water solution interface. The studied phospholipids differ not only as regards the structure of polar head-groups but also in the length of hydrophobic chains as well as their saturation degree. These differences result also in the main properties and functions of these phospholipids in biomembranes. The analysis of the results was based on the characteristics of the surface pressure (π)--area (A) isotherms registered for monolayers spread on the subphase containing plant hormone and as a reference on the surface of pure water. Moreover, as a complementary technique, Brewster angle microscopy was applied for the direct visualization of the investigated surface films. The obtained results revealed that auxins effectively influence phospholipids monolayers, regardless of the lipid structure, at the concentration of 10(-4)M. It was found that for this concentration, the influence of auxins was visibly larger in the case of PCs as compared to PEs. On the other hand, in the case of auxins solution of ≤ 10(-5)M, the observed trend was opposite. Generally, our studies showed that the natural plant hormone (IAA) interacts with the investigated lipid monolayers stronger than its synthetic derivative (NAA). The reason of these differences connects with the steric properties of both auxins; namely, the naphthalene ring of NAA molecule occupies larger space than the indole system of IAA. Therefore molecules of the latter compound penetrate easier into the region of phospholipids׳ polar head

  19. Dissecting Oceanic Detachment Faults: Fault Zone Geometry, Deformation Mechanisms, and Nature of Fluid-Rock Interactions

    NASA Astrophysics Data System (ADS)

    Bonnemains, D.; Escartin, J.; Verlaguet, A.; Andreani, M.; Mevel, C.

    2015-12-01

    To understand the extreme strain localization at long-lived oceanic detachment faults rooting deeply below the axis, we present results of geological investigations at the 13°19'N detachment along the Mid-Atlantic Ridge, conducted during the ODEMAR cruise (Nov-Dec13, NO Pourquoi Pas?) with ROV Victor6000 (IFREMER). During this cruise we investigated and sampled the corrugated fault to understand its geometry, nature of deformation, and links to fluid flow. We identified and explored 7 fault outcrops on the flanks of microbathymetric striations subparallel to extension. These outcrops expose extensive fault planes, with the most prominent ones extending 40-90m laterally, and up to 10 m vertically. These fault surfaces systematically show subhorizontal striations subparallel to extension, and define slabs of fault-rock that are flat and also striated at sample scale. Visual observations show a complex detachment fault zone, with anastomosing fault planes at outcrop scale (1-10 m), with a highly heterogeneous distribution of deformation. We observe heterogeneity in fault-rock nature at outcrop scale. In situ samples from striated faults are primarily basalt breccias with prior green-schist facies alteration, and a few ultramafic fault-rocks that show a complex deformation history, with early schistose textures, brittlely reworked as clasts within the fault. The basalt breccias show variable silicification and associated sulfides, recording important fluid-rock interactions during exhumation. To understand the link between fluid and deformation during exhumation, we will present microstructural observation of deformation textures, composition, and distribution and origin of quartz and sulfides, as well as constraints on the temperature of silicifying fluids from fluid inclusions in quartz. These results allow us to characterize in detail the detachment fault zone geometry, and investigate the timing of silicification relative to deformation.

  20. Infrared spectroscopic examination of the interaction of urea with the naturally occurring zeolite clinoptilolite

    USGS Publications Warehouse

    Byler, D.M.; Gerasimowicz, W.V.; Stockette, V.M.; Eberl, D.D.

    1991-01-01

    Infrared spectroscopy has shown for the first time that the naturally occurring zeolite clinoptilolite can absorb urea, (NH2)2CO, under ambient conditions from either aqueous or ethanolic solutions. The two strongest NH stretching bands at 3441 and 3344 cm-1 in pure, solid urea shift to higher frequency (about 3504 and 3401 cm-1) after absorption. Two of the four urea bands in the 1800-1300 cm-1 range (at 1683 and 1467 cm-1) undergo marked downward shifts to about 1670 and 1445 cm-1. The other two bands show little change in frequency. The strong band at 1602 cm-1, however, diminishes in intensity to little more than an ill-defined shoulder on the 1626-cm-1 peak. When clinoptilolite is heated to 450 ??C and then treated with molten urea (ca. 140 ??C) for several minutes, and finally washed twice with ethanol to remove excess unreacted urea, further changes become apparent in the spectrum of the urea-treated clinoptilolite. The two NH stretching bands broaden without significant change in frequency. Two new bands appear in the midfrequency range at 1777 (weak) and 1719 (medium strong) cm-1. Of the four original midfrequency peaks, the one at 1602 cm-1 is now absent. Two others (1627 and 1440 cm-1) exhibit little change, while the fourth has broadened and shifted down to 1663 cm-1, where it appears as a shoulder on the band at 1627 cm-1. Both treatments clearly induce interaction between urea and the zeolite which seems to result in significant modifications in the nature of the hydrogen bonding of the substrate. ?? 1991.

  1. Natural gas conversion to higher hydrocarbons using plasma interactions with surfaces. Final report

    SciTech Connect

    Sackinger, W.M.; Kamath, V.A.; Morgan, B.L.; Airey, R.W.

    1993-12-01

    Experiments are reported in which a methane plasma is created, and the methyl ions and hydrogen ions are accelerated within a microchannel array so that they interact with neutral methane molecules on the inside surfaces of the microchannels. No catalysts are used, and the device operates at room temperature. Impact energies of the ions are in the range of 10 eV to greater than 100 eV, and the energy delivered in the interaction at the surfaces causes the production of larger hydrocarbon molecules, such as C{sub 2}H{sub 2}, C{sub 2}H{sub 4}, and C{sub 2}H{sub 6}, along with C{sub 3}, C{sub 4}, C{sub 5}m C{sub 6}, C{sub 7}m and C{sub 8} molecules. There is a decreasing percentage of larger molecules produced, in comparison with the C{sub 2} and C{sub 3} types. Conversion effectiveness is greater at higher pressure, due to the increased ionic activity. The yield of the higher hydrocarbons depends upon the external voltage used, and voltage can be used as a control parameter to adjust the output mixture proportions. A conversion energy of 2.59 kilowatt hours/killogram of output has been demonstrated, and a reduction of this by a factor of 10 is possible using known techniques. In batch experiments, the selectivity for C{sub 2} has varied from 47% to 88%, and selectivity for C{sub 6} has ranged from 0% to 12.8%. Other hydrocarbon selectivities also span a wide and useful range. The estimated costs for hydrocarbons produced with this technology are in the range of $200 per tonne, in production quantities, depending upon natural gas costs. Pilot production experiments are recommended to make these estimates more precise, and to address strategies for scaling the technology up to production levels. Applications are discussed.

  2. Perceiving referential intent: Dynamics of reference in natural parent-child interactions

    PubMed Central

    Trueswell, John C.; Lin, Yi; Armstrong, Benjamin; Cartmill, Erica A.; Goldin-Meadow, Susan; Gleitman, Lila R.

    2016-01-01

    Two studies are presented which examined the temporal dynamics of the social-attentive behaviors that co-occur with referent identification during natural parent-child interactions in the home. Study 1 focused on 6.2 hours of videos of 56 parents interacting during everyday activities with their 14–18 month-olds, during which parents uttered common nouns as parts of spontaneously occurring utterances. Trained coders recorded, on a second-by-second basis, parent and child attentional behaviors relevant to reference in the period (40 sec.) immediately surrounding parental naming. The referential transparency of each interaction was independently assessed by having naïve adult participants guess what word the parent had uttered in these video segments, but with the audio turned off, forcing them to use only non-linguistic evidence available in the ongoing stream of events. We found a great deal of ambiguity in the input along with a few potent moments of word-referent transparency; these transparent moments have a particular temporal signature with respect to parent and child attentive behavior: it was the object’s appearance and/or the fact that it captured parent/child attention at the moment the word was uttered, not the presence of the object throughout the video, that predicted observers’ accuracy. Study 2 experimentally investigated the precision of the timing relation, and whether it has an effect on observer accuracy, by disrupting the timing between when the word was uttered and the behaviors present in the videos as they were originally recorded. Disrupting timing by only +/− 1 to 2 sec. reduced participant confidence and significantly decreased their accuracy in word identification. The results enhance an expanding literature on how dyadic attentional factors can influence early vocabulary growth. By hypothesis, this kind of time-sensitive data-selection process operates as a filter on input, removing many extraneous and ill-supported word

  3. Characteristics and nature of the halogen-bonding interactions between CCl3F and ozone: a supermolecular and SAPT study

    NASA Astrophysics Data System (ADS)

    Esrafili, Mehdi D.; Yourdkhani, Sirous; Bahrami, Aidin

    2013-12-01

    The strength and nature of the halogen-bond interactions in CCl3F...O3 complexes were examined by means of ab initio quantum-chemical calculations and symmetry-adapted perturbation theory (SAPT). Our calculations predict a trifurcated C-Cl...O interaction for the global minimum of CCl3F...O3 complex and several local minima, differing slightly in energy, separated by very low barriers. The calculations, which include a rigorous decomposition of the interaction energies, also indicate that the interaction of CCl3F molecule with O3 is characterised by contributions from both electrostatic and dispersion energies, with the contribution of the latter being dominant. The evaluated SAPT interaction energies for the CCl3F...O3 complexes are generally in good agreement with those obtained using the supermolecule CCSD(T) method, suggesting that SAPT is a proper method to study the intermolecular interactions in these complexes.

  4. The Fragment Molecular Orbital Method Reveals New Insight into the Chemical Nature of GPCR-Ligand Interactions.

    PubMed

    Heifetz, Alexander; Chudyk, Ewa I; Gleave, Laura; Aldeghi, Matteo; Cherezov, Vadim; Fedorov, Dmitri G; Biggin, Philip C; Bodkin, Mike J

    2016-01-25

    Our interpretation of ligand-protein interactions is often informed by high-resolution structures, which represent the cornerstone of structure-based drug design. However, visual inspection and molecular mechanics approaches cannot explain the full complexity of molecular interactions. Quantum Mechanics approaches are often too computationally expensive, but one method, Fragment Molecular Orbital (FMO), offers an excellent compromise and has the potential to reveal key interactions that would otherwise be hard to detect. To illustrate this, we have applied the FMO method to 18 Class A GPCR-ligand crystal structures, representing different branches of the GPCR genome. Our work reveals key interactions that are often omitted from structure-based descriptions, including hydrophobic interactions, nonclassical hydrogen bonds, and the involvement of backbone atoms. This approach provides a more comprehensive picture of receptor-ligand interactions than is currently used and should prove useful for evaluation of the chemical nature of ligand binding and to support structure-based drug design.

  5. Food plant derived disease tolerance and resistance in a natural butterfly-plant-parasite interactions.

    PubMed

    Sternberg, Eleanore D; Lefèvre, Thierry; Li, James; de Castillejo, Carlos Lopez Fernandez; Li, Hui; Hunter, Mark D; de Roode, Jacobus C

    2012-11-01

    Organisms can protect themselves against parasite-induced fitness costs through resistance or tolerance. Resistance includes mechanisms that prevent infection or limit parasite growth while tolerance alleviates the fitness costs from parasitism without limiting infection. Although tolerance and resistance affect host-parasite coevolution in fundamentally different ways, tolerance has often been ignored in animal-parasite systems. Where it has been studied, tolerance has been assumed to be a genetic mechanism, unaffected by the host environment. Here we studied the effects of host ecology on tolerance and resistance to infection by rearing monarch butterflies on 12 different species of milkweed food plants and infecting them with a naturally occurring protozoan parasite. Our results show that monarch butterflies experience different levels of tolerance to parasitism depending on the species of milkweed that they feed on, with some species providing over twofold greater tolerance than other milkweed species. Resistance was also affected by milkweed species, but there was no relationship between milkweed-conferred resistance and tolerance. Chemical analysis suggests that infected monarchs obtain highest fitness when reared on milkweeds with an intermediate concentration, diversity, and polarity of toxic secondary plant chemicals known as cardenolides. Our results demonstrate that environmental factors-such as interacting species in ecological food webs-are important drivers of disease tolerance.

  6. Natural Interactions between S. haematobium and S. guineensis in the Republic of Benin

    PubMed Central

    Moné, Hélène; Minguez, Stéphanie; Ibikounlé, Moudachirou; Allienne, Jean-François; Massougbodji, Achille; Mouahid, Gabriel

    2012-01-01

    Schistosomiasis is a parasitic disease which affects millions of people around the world, particularly in Africa. In this continent, different species are able to interbreed, like Schistosoma haematobium and Schistosoma guineensis, two schistosome species infecting humans. The Republic of Benin is known to harbor S. haematobium, but its geographical situation in between Nigeria, Mali, and Burkina Faso, where S. guineensis was found, raises the question about the possible presence of S. haematobium/S. guineensis hybrids in this country. We conducted morphological analyses on schistosome eggs and molecular analyses on schistosome larvae (high resolution melting (HRM) analysis and gene sequencing) in order to detect any natural interaction between these two species of schistosomes. The morphological results showed the presence of three egg morphotypes (S. haematobium, S. guineensis, and intermediate). Three genotypes were detected by ITS2 rDNA HRM analysis: S. haematobium, S. guineensis, and hybrid, and their percentages confirmed the results of the morphological analysis. However, sequencing of the CO1 mtDNA gene showed that all the samples from Benin belonged to S. haematobium. Our results provide the first evidence of introgression of S. guineensis genes in S. haematobium in Benin. PMID:22645454

  7. Anti-proliferative activity of the NPM1 interacting natural product avrainvillamide in acute myeloid leukemia.

    PubMed

    Andresen, Vibeke; Erikstein, Bjarte S; Mukherjee, Herschel; Sulen, André; Popa, Mihaela; Sørnes, Steinar; Reikvam, Håkon; Chan, Kok-Ping; Hovland, Randi; McCormack, Emmet; Bruserud, Øystein; Myers, Andrew G; Gjertsen, Bjørn T

    2016-12-01

    Mutated nucleophosmin 1 (NPM1) acts as a proto-oncogene and is present in ~30% of patients with acute myeloid leukemia (AML). Here we examined the in vitro and in vivo anti-leukemic activity of the NPM1 and chromosome region maintenance 1 homolog (CRM1) interacting natural product avrainvillamide (AVA) and a fully syntetic AVA analog. The NPM1-mutated cell line OCI-AML3 and normal karyotype primary AML cells with NPM1 mutations were significantly more sensitive towards AVA than cells expressing wild-type (wt) NPM1. Furthermore, the presence of wt p53 sensitized cells toward AVA. Cells exhibiting fms-like tyrosine kinase 3 (FLT3) internal tandem duplication mutations also displayed a trend toward increased sensitivity to AVA. AVA treatment induced nuclear retention of the NPM1 mutant protein (NPMc+) in OCI-AML3 cells and primary AML cells, caused proteasomal degradation of NPMc+ and the nuclear export factor CRM1 and downregulated wt FLT3 protein. In addition, both AVA and its analog induced differentiation of OCI-AML3 cells together with an increased phagocytotic activity and oxidative burst potential. Finally, the AVA analog displayed anti-proliferative activity against subcutaneous xenografted HCT-116 and OCI-AML3 cells in mice. Our results demonstrate that AVA displays enhanced potency against defined subsets of AML cells, suggesting that therapeutic intervention employing AVA or related compounds may be feasible.

  8. Doses and risks from uranium are not increased significantly by interactions with natural background photon radiation.

    PubMed

    Tanner, R J; Eakins, J S; Jansen, J T M; Harrison, J D

    2012-08-01

    The impact of depleted uranium (DU) on human health has been the subject of much conjecture. Both the chemical and radiological aspects of its behaviour in the human body have previously been investigated in detail, with the radiological impact being assumed to be linked to the alpha decay of uranium. More recently, it has been proposed that the accumulation in tissue of high-Z materials, such as DU, may give rise to enhanced local energy deposition in the presence of natural background photon radiation due to the high photoelectric interaction cross sections of high-Z atoms. It is speculated that, in addition to producing short-range photoelectrons, these events will be followed by intense Auger and Coster-Kronig electron emission, thereby causing levels of cell damage that are unaccounted for in conventional models of radiological risk. In this study, the physical and biological bases of these claims are investigated. The potential magnitudes of any effect are evaluated and discussed, and compared with the risks from other radiological or chemical hazards. Monte Carlo calculations are performed to estimate likely energy depositions due to the presence of uranium in human tissues in photon fields: whole body doses, organ doses in anthropomorphic phantoms and nano-/micro-dosimetric scenarios are each considered. The proposal is shown generally to be based on sound physics, but overall the impact on human health is expected to be negligible.

  9. Interaction of natural survival instincts and internalized social norms exploring the Titanic and Lusitania disasters.

    PubMed

    Frey, Bruno S; Savage, David A; Torgler, Benno

    2010-03-16

    To understand human behavior, it is important to know under what conditions people deviate from selfish rationality. This study explores the interaction of natural survival instincts and internalized social norms using data on the sinking of the Titanic and the Lusitania. We show that time pressure appears to be crucial when explaining behavior under extreme conditions of life and death. Even though the two vessels and the composition of their passengers were quite similar, the behavior of the individuals on board was dramatically different. On the Lusitania, selfish behavior dominated (which corresponds to the classical homo economicus); on the Titanic, social norms and social status (class) dominated, which contradicts standard economics. This difference could be attributed to the fact that the Lusitania sank in 18 min, creating a situation in which the short-run flight impulse dominated behavior. On the slowly sinking Titanic (2 h, 40 min), there was time for socially determined behavioral patterns to reemerge. Maritime disasters are traditionally not analyzed in a comparative manner with advanced statistical (econometric) techniques using individual data of the passengers and crew. Knowing human behavior under extreme conditions provides insight into how widely human behavior can vary, depending on differing external conditions.

  10. Inhibitory Network Interactions Shape the Auditory Processing of Natural Communication Signals in the Songbird Auditory Forebrain

    PubMed Central

    Pinaud, Raphael; Terleph, Thomas A.; Tremere, Liisa A.; Phan, Mimi L.; Dagostin, André A.; Leão, Ricardo M.; Mello, Claudio V.; Vicario, David S.

    2008-01-01

    The role of GABA in the central processing of complex auditory signals is not fully understood. We have studied the involvement of GABAA-mediated inhibition in the processing of birdsong, a learned vocal communication signal requiring intact hearing for its development and maintenance. We focused on caudomedial nidopallium (NCM), an area analogous to parts of the mammalian auditory cortex with selective responses to birdsong. We present evidence that GABAA-mediated inhibition plays a pronounced role in NCM's auditory processing of birdsong. Using immunocytochemistry, we show that approximately half of NCM's neurons are GABAergic. Whole cell patch-clamp recordings in a slice preparation demonstrate that, at rest, spontaneously active GABAergic synapses inhibit excitatory inputs onto NCM neurons via GABAA receptors. Multi-electrode electrophysiological recordings in awake birds show that local blockade of GABAA-mediated inhibition in NCM markedly affects the temporal pattern of song-evoked responses in NCM without modifications in frequency tuning. Surprisingly, this blockade increases the phasic and largely suppresses the tonic response component, reflecting dynamic relationships of inhibitory networks that could include disinhibition. Thus processing of learned natural communication sounds in songbirds, and possibly other vocal learners, may depend on complex interactions of inhibitory networks. PMID:18480371

  11. Interaction of natural survival instincts and internalized social norms exploring the Titanic and Lusitania disasters

    PubMed Central

    Frey, Bruno S.; Savage, David A.; Torgler, Benno

    2010-01-01

    To understand human behavior, it is important to know under what conditions people deviate from selfish rationality. This study explores the interaction of natural survival instincts and internalized social norms using data on the sinking of the Titanic and the Lusitania. We show that time pressure appears to be crucial when explaining behavior under extreme conditions of life and death. Even though the two vessels and the composition of their passengers were quite similar, the behavior of the individuals on board was dramatically different. On the Lusitania, selfish behavior dominated (which corresponds to the classical homo economicus); on the Titanic, social norms and social status (class) dominated, which contradicts standard economics. This difference could be attributed to the fact that the Lusitania sank in 18 min, creating a situation in which the short-run flight impulse dominated behavior. On the slowly sinking Titanic (2 h, 40 min), there was time for socially determined behavioral patterns to reemerge. Maritime disasters are traditionally not analyzed in a comparative manner with advanced statistical (econometric) techniques using individual data of the passengers and crew. Knowing human behavior under extreme conditions provides insight into how widely human behavior can vary, depending on differing external conditions. PMID:20194743

  12. Osteoarthritis: genes, nature-nurture interaction and the role of leptin.

    PubMed

    Garner, Malgorzata; Alshameeri, Zeiad; Khanduja, Vikas

    2013-12-01

    Osteoarthritis (OA) is a common disease affecting patients at different ages regardless of gender or ethnicity. As with many chronic diseases, OA is thought to have a multifactorial aetiology, which is not fully understood. Whereas the pathophysiological process of OA can be analysed at a cellular and molecular level, the interaction between genes and lifestyle remains an important factor in the development of this disease. The expanding awareness of different genes that may play a role in OA, together with many chemical mediators thought to be associated with the progression of the disease, will help in better management of this condition. Some of the chemical mediators recently implicated in this condition are the adipokines (leptin, adiponectin and resistin). Few but consistent studies suggest that leptin in association with obesity could be an important factor in OA aetiology. Hence, this could establish a strong and direct molecular link between patient life style (nurture) and the pathological process of OA (nature). However, neither a clear mechanism nor a direct clinical association linking leptin to OA has yet been established. In this article, we explore some of the genetic and environmental factors in OA aetiology. We discuss leptin in obesity and assess its possible association with OA aetiology. This should emphasise the important role of health professionals in treating obesity in order to control OA symptoms and possibly progression.

  13. Interaction of natural polyphenols with α-amylase in vitro: molecular property-affinity relationship aspect.

    PubMed

    Xiao, Jianbo; Kai, Guoyin; Ni, Xiaoling; Yang, Fan; Chen, Xiaoqing

    2011-06-01

    The relationship between the structural properties of natural polyphenols and their affinities for α-amylase were investigated by fluorescence titration analysis. The binding process with α-amylase was strongly influenced by the structural differences of the compounds under study. For instance, the methylation of the hydroxyl group in flavonoids increased their binding affinities for α-amylase by 2.14 to 7.76 times. The hydroxylation on rings A, B, and C of flavonoids also significantly affected their affinities for α-amylase. The glycosylation of isoflavones and flavanones reduced their affinities for α-amylase and the glycosylation of flavones and flavonols enhanced their affinities for α-amylase. Hydrogenation of the C2=C3 double bond of flavonoids decreased the binding affinities. The galloylated catechins had higher binding affinities with α-amylase than non-galloylated catechins and the pyrogallol-type catechins had higher affinities than the catechol-type catechins. The presence of the galloyl moiety is the most decisive factor. The glycosylation of resveratrol decreased its affinity for α-amylase. The esterification of gallic acid significantly reduced the affinity for α-amylase. The binding interaction between polyphenols and α-amylase was mainly caused by hydrophobic forces.

  14. Interactive effects of Na and K in killing by natural killer cells

    SciTech Connect

    Schlichter, L.C.; MacCoubrey, I.C. )

    1989-09-01

    Contact-mediated lysis by human natural killer cells is inhibited by a number of drugs that block the predominant K channel. In this study the authors have further examined the role of the K channel and the interactions between passive K and Na transport in killing. Low external Na-inhibited killing and inhibition were not due to reduced inward current through the Na channels in the target cell. A role for the Na/H antiport is suggested since amiloride inhibited killing in a dose-dependent manner that was competitive with external Na. Depolarizing the killer cell with elevated external K did not inhibit killing. On the contrary, high K{sub 0} reduced the inhibition caused by low Na{sub 0} and by the K-channel blockers quinidine, verapamil, and retinoic acid. Hyperpolarizing the killer cell with low K{sub 0} or valinomycin inhibited killing. Hence, the primary role of the K channels during killing is not to maintain the negative membrane potential. On the contrary, depolarization may promote killing under conditions where killing is submaximal.

  15. Anti-proliferative activity of the NPM1 interacting natural product avrainvillamide in acute myeloid leukemia

    PubMed Central

    Andresen, Vibeke; Erikstein, Bjarte S; Mukherjee, Herschel; Sulen, André; Popa, Mihaela; Sørnes, Steinar; Reikvam, Håkon; Chan, Kok-Ping; Hovland, Randi; McCormack, Emmet; Bruserud, Øystein; Myers, Andrew G; Gjertsen, Bjørn T

    2016-01-01

    Mutated nucleophosmin 1 (NPM1) acts as a proto-oncogene and is present in ~30% of patients with acute myeloid leukemia (AML). Here we examined the in vitro and in vivo anti-leukemic activity of the NPM1 and chromosome region maintenance 1 homolog (CRM1) interacting natural product avrainvillamide (AVA) and a fully syntetic AVA analog. The NPM1-mutated cell line OCI-AML3 and normal karyotype primary AML cells with NPM1 mutations were significantly more sensitive towards AVA than cells expressing wild-type (wt) NPM1. Furthermore, the presence of wt p53 sensitized cells toward AVA. Cells exhibiting fms-like tyrosine kinase 3 (FLT3) internal tandem duplication mutations also displayed a trend toward increased sensitivity to AVA. AVA treatment induced nuclear retention of the NPM1 mutant protein (NPMc+) in OCI-AML3 cells and primary AML cells, caused proteasomal degradation of NPMc+ and the nuclear export factor CRM1 and downregulated wt FLT3 protein. In addition, both AVA and its analog induced differentiation of OCI-AML3 cells together with an increased phagocytotic activity and oxidative burst potential. Finally, the AVA analog displayed anti-proliferative activity against subcutaneous xenografted HCT-116 and OCI-AML3 cells in mice. Our results demonstrate that AVA displays enhanced potency against defined subsets of AML cells, suggesting that therapeutic intervention employing AVA or related compounds may be feasible. PMID:27906185

  16. Rethinking Traffic Management: Design of Optimizable Networks

    DTIC Science & Technology

    2008-06-01

    general, boldface are used to denote vectors and small letters are used to denote its components, e.g., x with xi as its i th component; capital letters...which is represen- tative of a common network structure . In the middle is a full mesh representing the core of the network with rich connectivity. On...Aggregate utility gap for the N -node, 1-destination ring. Given the structure of (3.2), it is natural to wonder if the interaction of congestion control

  17. How 'alternative' is CAM? Rethinking conventional dichotomies between biomedicine and complementary/alternative medicine.

    PubMed

    Ning, Ana M

    2013-03-01

    The aim of this article is to interrogate the pervasive dichotomization of 'conventional' and 'alternative' therapies in popular, academic and medical literature. Specifically, I rethink the concepts such as holism, vitalism, spirituality, natural healing and individual responsibility for health care as taken-for-granted alternative ideologies. I explore how these ideologies are not necessarily 'alternative', but integral to the practice of clinical medicine as well as socially and culturally dominant values, norms and practices related to health and health care in Canada and elsewhere. These reflections address both theoretical and applied concerns central to the study of integration of different medical practices in western industrialized nations such as Canada. Overall, in examining homologies present in both biomedicine and complementary/alternative medicine (CAM), this article rethinks major social practices against binary oppositions by illustrating through literature review that the biomedical and CAM models may be homologous in their original inceptions and in recent cross-fertilizations towards a rigorous approach in medicine. By highlighting biomedicine and CAM as homologous symbolic systems, this article also sheds light on the potential for enhancing dialogue between diverse perspectives to facilitate an integrative health care system that meets multiple consumer needs.

  18. Nature and consequences of non-covalent interactions between flavonoids and macronutrients in foods.

    PubMed

    Bordenave, Nicolas; Hamaker, Bruce R; Ferruzzi, Mario G

    2014-01-01

    Many of the potential health benefits of flavonoids have been associated with their specific chemical and biological properties including their ability to interact and bind non-covalently to macronutrients in foods. While flavonoid-protein interactions and binding have been the subject of intensive study, significantly less is understood about non-covalent interactions with carbohydrates and lipids. These interactions with macronutrients are likely to impact both the flavonoid properties in foods, such as their radical scavenging activity, and the food or beverage matrix itself, including their taste, texture and other sensorial properties. Overall, non-covalent binding of flavonoids with macronutrients is primarily driven by van der Waals interactions. From the flavonoid perspective, these interactions are modulated by characteristics such as degree of polymerization, molecular flexibility, number of external hydroxyl groups, or number of terminal galloyl groups. From the macronutrient standpoint, electrostatic and ionic interactions are generally predominant with carbohydrates, while hydrophobic interactions are generally predominant with lipids and mainly limited to interactions with flavonols. All of these interactions are involved in flavonoid-protein interactions. While primarily associated with undesirable characteristics in foods and beverages, such as astringency, negative impact on macronutrient digestibility and hazing, more recent efforts have attempted to leverage these interactions to develop controlled delivery systems or strategies to enhance flavonoids bioavailability. This paper aims at reviewing the fundamental bases for non-covalent interactions, their occurrence in food and beverage systems and their impact on the physico-chemical, organoleptic and some nutritional properties of food.

  19. Nature of Hydrogen Bonds and S···S Interactions in the l-Cystine Crystal.

    PubMed

    Flores-Huerta, Anaid G; Tkatchenko, Alexandre; Galván, Marcelo

    2016-06-23

    The intermolecular interactions that govern the stability of the l-cystine crystal were studied. This task is accomplished by using density-functional theory (DFT) with the generalized-gradient approximation (GGA) and including many-body dispersion (MBD) interactions. The strengths of the different interactions within the molecular crystal were obtained by a decomposition of the total interaction energy in two-, three-, and four-body contributions. It was determined that most of the hydrogen bonds formed within the crystal are strong (13, 15, and 19 kcal/mol) and the van der Waals nature of the S···S interaction is fully confirmed. Also, the presence of strong repulsive three-body contributions is determined. The results obtained support the idea of designing crystal growth inhibitors for this system in such a way that, when inserted in the crystal, they maintain the disulfide bridge environment but its capacity of generate hydrogen-bond networks is removed.

  20. Microbial Interactions with Natural Organic Matter Extracted from the Oak Ridge FRC

    NASA Astrophysics Data System (ADS)

    Wu, X.; Jagadamma, S.; Lancaster, A.; Adams, M. W. W.; Hazen, T.; Justice, N.; Chakraborty, R.

    2015-12-01

    Natural organic matter (NOM) is central to microbial food webs; however, little is known about the interplay between the physical and chemical characteristics of NOM and its turnover by microbial communities based upon biotic and abiotic parameters (e.g., biogenic precursors, redox state, bioavailability). Microbial activity changes the structures and properties that influence further bioavailability of NOM. To date, our understanding of these interactions is insufficient, and indigenous microbial activities that regulate NOM turnover are poorly resolved. It is critical to identify NOM characteristics to the structure and composition of microbial communities and to the metabolic potential of that community. Towards that end, sediment samples collected from the background area well FW305 (Oak Ridge Field Research Center, Oak Ridge, TN) were tested for NOM extraction methods that used three mild solvents, e.g., phosphate buffered saline (PBS), pyrophosphate, and MilliQ-water. MilliQ-water was finally chosen for extracting sediment samples via shaking and sonication. Groundwater from well FW301 was used as an inoculum to which the extracted NOM was added as carbon sources to feed native microbes. To identify the specific functional groups of extracted NOM that are bioavailable to indigenous microbes, several techniques, including FTIR, LC-MS, EEM, were applied to characterize the extracted NOM as well as the transformed NOM metabolites. 16S rDNA amplicon sequencing was also performed to identify the specific microbial diversity that was enriched and microbial isolates that preferentially grew with these NOM was also cultivated in the lab for future detailed studies.

  1. New physics at the weak scale: axigluon models, scale invariance and naturalness, and interacting dark matter

    NASA Astrophysics Data System (ADS)

    Tavares, Gustavo Marques

    The Standard Model of particle physics describes all known elementary particles and their interactions. Despite its great experimental success, we know that the Standard Model is not a complete description of Nature and therefore new phenomena should be observed at higher energies. In the coming years the Large Hadron Collider will test the Standard Model by colliding protons with center of mass energies of up to 14 TeV providing some of the most stringent tests on the Standard Model. Experimental searches for Dark Matter provide a complementary program to test physics at the weak scale. In the near future new experimental data coming from direct detection experiments, and from satellites and telescopes will drastically improve our sensitivity to weak scale dark matter. This could lead to the first direct observation of dark matter, and thus of physics beyond the Standard Model. In this thesis I propose different extensions of the Standard Model and discuss their experimental consequences. I first discuss models for Axigluons, which are spin one particles in the adjoint representation of the SU(3) color gauge group. These models were motivated by the measurement of higher than predicted forward-backward asymmetry in top quark pair production at the Tevatron. I study different scenarios for Axigluon models that can explain the Tevatron result and explore their signatures at the Large Hadron Collider. Second I discuss the implications of ultraviolet scale invariance for the Standard Model, which has been advocated as a solution to the hierarchy problem. I show that in order to solve the hierarchy problem with scale invariance, new physics is required not far from the weak scale. In the last part of this thesis I propose a new model for dark matter, in which dark matter is charged under a hidden non-Abelian gauge group. This leads to modifications in the sensitivity of the usual experimental searches for dark matter in addition to distinct signatures in the Cosmic

  2. The Nature of Negotiations in Face-to-Face versus Computer-Mediated Communication in Pair Interactions

    ERIC Educational Resources Information Center

    Rouhshad, Amir; Wigglesworth, Gillian; Storch, Neomy

    2016-01-01

    The Interaction Approach argues that negotiation for meaning and form is conducive to second language development. To date, most of the research on negotiations has been either in face-to-face (FTF) or text-based synchronous computer-mediated communication (SCMC) modes. Very few studies have compared the nature of negotiations across the modes.…

  3. The Nature of Children's Interactions while Composing Together on Computers. CIERA Report.

    ERIC Educational Resources Information Center

    Lomangino, Adrienne Gelpi; Nicholson, Julie; Sulzby, Elizabeth

    Patterns of interaction, including power relations and social goals, were investigated by observing first-grade children over a 5-month period as they worked in small groups to compose stories on the computer. Three groups selected for in-depth analysis represent the wide range of observed interaction patterns. Differences in interaction patterns…

  4. The Nature of Adolescent Learner Interaction in a Virtual High School Setting

    ERIC Educational Resources Information Center

    Borup, J.; Graham, C.R.; Davies, R.S.

    2013-01-01

    This study used survey data to measure the effect of learners' reported interactions with content, peers, and instructors on several course outcomes in two virtual high school courses that emphasized interactive learning. Surveys found that the large majority of students viewed all investigated types of interaction as educational and motivational.…

  5. Nature of intramolecular interactions of vitamin C in view of interacting quantum atoms: the role of hydrogen bond cooperativity on geometry.

    PubMed

    Ebrahimi, Saeid; Dabbagh, Hossein A; Eskandari, Kiamars

    2016-07-21

    The conformational analysis of six dihedral angles was calculated by second-order Moller-Plesset perturbation theory (MP2) with the correlation-consistent aug-cc-pVDZ basis set. The quantum theory of atoms in molecules (QTAIM) was applied to gain a description of the atoms and chemical bonds. A high content of hydroxyl groups in vitamin C's (VC) structure leads to a wide range of intramolecular interactions. The nature of these interactions within the selected VC conformers was studied in view of the interacting quantum atom (IQA) approach. Complete IQA analysis of the atomic and interatomic interaction energies indicated hydrogen bond formation was responsible for the stability of most of the local minima in the potential energy surface. In these conformers, the tandem participation of interactions was operating by way of two- or three-centered (bifurcated) cooperative networks. For the intramolecular hydrogen bond interplay in cooperativity, changes of the IQA atomic and interatomic interaction energies of the participant interactions were monitored during the formation of cooperative networks. The results of the intramolecular cooperativity were evaluated with changes of the delocalization index and bond distances.

  6. 5G: rethink mobile communications for 2020+.

    PubMed

    Chih-Lin, I; Han, Shuangfeng; Xu, Zhikun; Sun, Qi; Pan, Zhengang

    2016-03-06

    The 5G network is anticipated to meet the challenging requirements of mobile traffic in the 2020s, which are characterized by super high data rate, low latency, high mobility, high energy efficiency and high traffic density. This paper provides an overview of China Mobile's 5G vision and potential solutions. Three key characteristics of 5G are analysed, i.e. super fast, soft and green. The main 5G R&D themes are further elaborated, which include five fundamental rethinkings of the traditional design methodologies. The 5G network design considerations are also discussed, with cloud radio access network, ultra-dense network, software defined network and network function virtualization examined as key potential solutions towards a green and soft 5G network. The paradigm shift to user-centric network operation from the traditional cell-centric operation is also investigated, where the decoupled downlink and uplink, control and data, and adaptive multiple connections provide sufficient means to achieve a user-centric 5G network with 'no more cells'. The software defined air interface is investigated under a uniform framework and can adaptively adapt the parameters to well satisfy various requirements in different 5G scenarios.

  7. Microbial Dysbiosis: Rethinking Disease in Marine Ecosystems

    PubMed Central

    Egan, Suhelen; Gardiner, Melissa

    2016-01-01

    With growing environmental pressures placed on our marine habitats there is concern that the prevalence and severity of diseases affecting marine organisms will increase. Yet relative to terrestrial systems, we know little about the underlying causes of many of these diseases. Moreover, factors such as saprophytic colonizers and a lack of baseline data on healthy individuals make it difficult to accurately assess the role of specific microbial pathogens in disease states. Emerging evidence in the field of medicine suggests that a growing number of human diseases result from a microbiome imbalance (or dysbiosis), questioning the traditional view of a singular pathogenic agent. Here we discuss the possibility that many diseases seen in marine systems are, similarly, the result of microbial dysbiosis and the rise of opportunistic or polymicrobial infections. Thus, understanding and managing disease in the future will require us to also rethink definitions of disease and pathogenesis for marine systems. We suggest that a targeted, multidisciplinary approach that addresses the questions of microbial symbiosis in both healthy and diseased states, and at that the level of the holobiont, will be key to progress in this area. PMID:27446031

  8. Microbial Dysbiosis: Rethinking Disease in Marine Ecosystems.

    PubMed

    Egan, Suhelen; Gardiner, Melissa

    2016-01-01

    With growing environmental pressures placed on our marine habitats there is concern that the prevalence and severity of diseases affecting marine organisms will increase. Yet relative to terrestrial systems, we know little about the underlying causes of many of these diseases. Moreover, factors such as saprophytic colonizers and a lack of baseline data on healthy individuals make it difficult to accurately assess the role of specific microbial pathogens in disease states. Emerging evidence in the field of medicine suggests that a growing number of human diseases result from a microbiome imbalance (or dysbiosis), questioning the traditional view of a singular pathogenic agent. Here we discuss the possibility that many diseases seen in marine systems are, similarly, the result of microbial dysbiosis and the rise of opportunistic or polymicrobial infections. Thus, understanding and managing disease in the future will require us to also rethink definitions of disease and pathogenesis for marine systems. We suggest that a targeted, multidisciplinary approach that addresses the questions of microbial symbiosis in both healthy and diseased states, and at that the level of the holobiont, will be key to progress in this area.

  9. Rethinking sanitation: panacea or Pandora's box.

    PubMed

    Esrey, S A

    2000-01-01

    In the 19th century, sanitation solutions were designed and built on the premises that human excreta was a waste suitable only for disposal and that the environment was capable of assimilating the waste. The prevailing view last century was that vapors from smells caused disease, and the best way to deal with excreta was to convey it to rivers and streams where it could be diluted and cleansed. Times have changed, the premises are outdated, and current solutions contribute, either directly or indirectly, to many of the problems faced by society today: water pollution, scarcity of fresh water, food insecurity, destruction and loss of soil fertility, loss of biodiversity, depletion of the ozone layer, and global warming. A common denominator of all these problems is how society deals with its wastes, specifically how it deals with human excrement. We have to rethink past premises, design and build new systems, and contribute to the solving of society's most pressing problems. The panacea of the 19th century is turning out to be the pandora's box of the 21st century.

  10. Representing the nature of science in a science textbook: Exploring author-editor-publisher interactions

    NASA Astrophysics Data System (ADS)

    Digiuseppe, Maurizio

    Current reforms in elementary and secondary science education call for students and teachers to develop more informed views of the nature of science---a process in which learning materials like science textbooks play a significant role. This dissertation reports on a case study of the development of representations of the nature of science in one unit of a senior high school chemistry textbook by the book's author, editor, and publisher. The study examines the multiple discourses that arose as the developers reflected on their personal and shared understandings of the nature of science; squared these understandings with mandated curricula, the educational needs of chemistry students and teachers, and the exigencies of large-scale commercial textbook publishing; and developed and incorporated into the textbook representations of the nature of science they believed were the most suitable. Analyses of the data in this study indicate that a number of factors significantly influenced the development of representations of the nature of science, including representational accuracy (the degree to which suggested representations of the nature of science conformed to what the developers believed were contemporary understandings of the nature of science), representational consistency (the degree to which similar representations of the nature of science in different parts of the textbook conveyed the same meaning), representational appropriateness (the age-, grade-, and reading-level suitability of the suggested nature of science representations), representational alignment (the degree to which suggested representations of the nature of science addressed the requirements of mandated curricula), representational marketability (the degree to which textbook developers believed suggested representations of the nature of science would affect sales of the textbook in the marketplace), and a number of "Workplace Resources" factors such as the availability of time, relevant expertise

  11. Interaction between anthelmintic treatment and vaccine responses in ponies naturally infected with cyathostomins.

    PubMed

    Nielsen, M K; Rubinson, E F; Chambers, T M; Horohov, D W; Wagner, B; Betancourt, A; Reedy, S E; Jacobsen, S

    2015-04-15

    Anthelmintics and vaccines are commonly given concurrently in routine equine management, but it is unknown to what extent an interaction between the two exists. Cyathostomins can modulate the local immune response by stimulating a type 2 helper T cell (Th2) response. In addition, anti-inflammatory effects of ivermectin have been found in rodent models. It is unknown whether these anti-inflammatory effects affect the acute phase response elicited by commonly used vaccines. This study evaluated how the acute phase inflammatory response, leukocyte expression of pro-inflammatory cytokines, and vaccine-specific titers induced by simultaneous injection of three vaccines (West Nile Virus, Equine Herpes Rhinopneumonitis, and Keyhole Limpet Hemocyanin) were modulated by concurrent administration of ivermectin or pyrantel pamoate in ponies naturally infected with cyathostomins. Mixed-breed yearling ponies were blocked by gender and fecal strongyle egg count, then randomly assigned to three treatment groups: ivermectin (n=8), pyrantel pamoate (n=8), and control (n=7). All ponies received vaccinations intramuscularly on days 0 and 29, and anthelmintics were administered on the same days. Whole blood, serum and plasma samples were collected one, three and 14 days after each vaccination. Samples were analyzed for concentrations of acute phase reactants (haptoglobin, serum amyloid A, fibrinogen and iron), mRNA expression levels of cytokines (interleukin (IL)-1β, IL-4, IL-10, tumor necrosis factor (TNF)-α and interferon (IFN)-γ) in leukocytes, and vaccine-specific antibody titers. A marked acute-phase response was noted following both vaccinations. In contrast, the pattern of change in cytokine expression was less pronounced and more variable. Statistical differences were observed between groups for haptoglobin, fibrinogen, IL-1β, IL-4, and IL-10, but differences were generally small and none of the vaccine titers were different between the groups. Taken together, the study

  12. On the nature of the stacking interaction between two graphene layers

    NASA Astrophysics Data System (ADS)

    Wang, Weizhou; Zhang, Yu; Sun, Tao; Wang, Yi-Bo

    2015-01-01

    The interlayer interaction energy and its components of the bilayer graphene were obtained by extrapolation of the interlayer interaction energies and their components of the dimers formed by graphene with benzene, naphthalene, anthracene, phenanthrene, pyrene, tetracene, perylene, pentacene and hexacene. The resulting interaction energy of the bilayer graphene is -1.82 kcal/mol (or -79 meV) per carbon atom. The dispersion energy represents 70% of the total attractive energy between two graphene layers. In contrast, the electrostatic component is responsible for 25% of the total attractive interaction and the induction term contributes 5% to the stability of two graphene layers.

  13. Living on Borrowed Time: Rethinking Temporality, Self, Nihilism, and Schooling

    ERIC Educational Resources Information Center

    Rappleye, Jeremy; Komatsu, Hikaru

    2016-01-01

    Seeking to contribute to recent attempts to rethink the deepest foundations of the field, this paper offers news ways of contemplating time, specifically its relations to self, nihilism, and schooling. We briefly review how some leading Western thinkers have contemplated time before detailing Japanese scholars who have offered divergent, original,…

  14. Rethinking and Redesigning Education Assessment. Preschool through Postsecondary.

    ERIC Educational Resources Information Center

    Pellegrino, James W.

    The recent National Research Council (NRC) report, "Knowing What Students Know: The Science and Design of Educational Assessment," suggests that it is time to rethink the basic assumptions underlying assessment of students and the use of measurement data to enhance teaching and learning. This essay draws on arguments developed in the NRC report to…

  15. Rethinking Schools. An Agenda for Change. Leading Reformers Speak Out.

    ERIC Educational Resources Information Center

    Levine, David, Ed.; And Others

    This collection presents the best of 8 years of "Rethinking Schools," an education reform journal created in Milwaukee (Wisconsin) in 1986 by teachers vitally concerned with educational change. This volume contains 29 essays by classroom teachers, as well as pieces by such national reform figures as Henry Louis Gates, Jr., Herbert Kohl,…

  16. Caution or Stasis: Using Research to Rethink Schools--Now

    ERIC Educational Resources Information Center

    Blodget, Alden

    2016-01-01

    In this article, Alden Blodget reflects on his more than 50 years of working in what he terms "the tragicomedy club of school reform," and suggests a need to rethink not just classroom teaching methods but the entire system. Blodget states that if the current system is built on faulty assumptions about learning, then there must be a…

  17. Rethinking Education for the Caribbean: A Radical Approach

    ERIC Educational Resources Information Center

    Jules, Didacus

    2008-01-01

    The article reflects critically on the experience of the Caribbean Anglophone countries (CARICOM) in reforming their education systems to meet the challenges of the present era. It argues that education reform in the current conjuncture can no longer be incremental and that what is required is a fundamental rethinking of educational provision.…

  18. Rethinking Leadership Development: How School Leaders Learn in Action

    ERIC Educational Resources Information Center

    Mackenzie, Sarah V.; Marnik, George F.

    2008-01-01

    In order to meet the needs of evolving school leaders, university professors and others who provide professional development must rethink and expand their roles. Based on experiences as instructors in a leadership development program, the authors had the opportunity to explore and understand more fully how leaders grow. This article describes our…

  19. Rethinking Mathematics: Teaching Social Justice by the Numbers

    ERIC Educational Resources Information Center

    Gutstein, Eric, Ed.; Peterson, Bob, Ed.

    2005-01-01

    This unique collection of more than 30 articles shows teachers how to weave social-justice principles throughout the math curriculum, and how to integrate social-justice math into other curricular areas as well. "Rethinking Mathematics" presents teaching ideas, lesson plans and reflections by practicing classroom teachers and distinguished…

  20. Rethinking Our Classrooms: Teaching for Equity and Justice. Volume 2.

    ERIC Educational Resources Information Center

    Bigelow, Bill, Ed.; Harvey, Brenda, Ed.; Karp, Stan, Ed.; Miller, Larry, Ed.

    This companion volume to the first "Rethinking Our Classrooms" presents a collection of articles, curriculum ideas, lesson plans, poetry, and resources designed for educators seeking to pair concerns for social justice with student academic achievement. Topics are: (1) "The Power of Words," including "Where I'm From:…

  1. The Global Imperative: Rethinking the Economy, the Environment, and Education.

    ERIC Educational Resources Information Center

    Lukensmeyer, Carolyn J.

    The global imperative is acting on the reality that people's survival, the planet's existence, and the quality of humanity requires change in the relationship between economic development and environmental redevelopment. The destructive patterns of shortsighted global economic development warrant rethinking of the link between the economy and the…

  2. Rethinking Classroom Management: Strategies for Prevention, Intervention, and Problem Solving.

    ERIC Educational Resources Information Center

    Belvel, Patricia Sequeira; Jordan, Maya Marcia

    This book illustrates an approach to achieving a positive, harmonious classroom environment which enables educators to evolve effectively from managers to leaders by rethinking their roles as teachers, discussing how to create classrooms where students are more self-managing and demonstrate mutual respect, self-esteem, and responsibility. Key…

  3. Rethinking Validation in Complex High-Stakes Assessment Contexts

    ERIC Educational Resources Information Center

    Koch, Martha J.; DeLuca, Christopher

    2012-01-01

    In this article we rethink validation within the complex contexts of high-stakes assessment. We begin by considering the utility of existing models for validation and argue that these models tend to overlook some of the complexities inherent to assessment use, including the multiple interpretations of assessment purposes and the potential…

  4. Non-empirical analysis of the nature of the inhibitor active-site interactions in leucine aminopeptidase

    NASA Astrophysics Data System (ADS)

    Grembecka, J.; K ȩdzierski, P.; Sokalski, W. A.

    1999-11-01

    Non-empirical analysis of the physical nature of the intermolecular interactions between several leucine aminopeptidase inhibitors and various constituents of the enzyme active site has been performed using a direct version of the hybrid variation-perturbation decomposition of SCF and MP2 interaction energies. The interaction energy terms obtained at different theory levels have been correlated with experimentally measured activities of the inhibitors, indicating that the more advanced the quantum-chemical method and, the larger the active-site model, the better is the correlation between calculated and measured binding energies. The electrostatic multipole term constitutes the dominant contribution in the total interaction energy, whereas Zn 2+488 and Lys +262 enzyme residues play the crucial role in the binding of these inhibitors by leucine aminopeptidase.

  5. Magnitude and nature of carbohydrate-aromatic interactions in fucose-phenol and fucose-indole complexes: CCSD(T) level interaction energy calculations.

    PubMed

    Tsuzuki, Seiji; Uchimaru, Tadafumi; Mikami, Masuhiro

    2011-10-20

    The CH/π contact structures of the fucose-phenol and fucose-indole complexes and the stabilization energies by formation of the complexes (E(form)) were studied by ab initio molecular orbital calculations. The three types of interactions (CH/π and OH/π interactions and OH/O hydrogen bonds) were compared and evaluated in a single molecular system and at the same level of theory. The E(form) calculated for the most stable CH/π contact structure of the fucose-phenol complex at the CCSD(T) level (-4.9 kcal/mol) is close to that for the most stable CH/π contact structure of the fucose-benzene complex (-4.5 kcal/mol). On the other hand the most stable CH/π contact structure of the fucose-indole complex has substantially larger E(form) (-6.5 kcal/mol). The dispersion interaction is the major source of the attraction in the CH/π contact structures of the fucose-phenol and fucose-indole complexes as in the case of the fucose-benzene complex. The electrostatic interactions in the CH/π contact structures are small (less than 1.5 kcal/mol). The nature of the interactions between the nonpolar surface of the carbohydrate and aromatic rings is completely different from that of the conventional hydrogen bonds where the electrostatic interaction is the major source of the attraction. The distributed multipole analysis and DFT-SATP analysis show that the dispersion interactions in the CH/π contact structure of fucose-indole complex are substantially larger than those in the CH/π contact structures of fucose-benzene and fucose-phenol complexes. The large dispersion interactions are responsible for the large E(form) for the fucose-indole complex.

  6. Interactive rhythmic auditory stimulation reinstates natural 1/f timing in gait of Parkinson's patients.

    PubMed

    Hove, Michael J; Suzuki, Kazuki; Uchitomi, Hirotaka; Orimo, Satoshi; Miyake, Yoshihiro

    2012-01-01

    Parkinson's disease (PD) and basal ganglia dysfunction impair movement timing, which leads to gait instability and falls. Parkinsonian gait consists of random, disconnected stride times--rather than the 1/f structure observed in healthy gait--and this randomness of stride times (low fractal scaling) predicts falling. Walking with fixed-tempo Rhythmic Auditory Stimulation (RAS) can improve many aspects of gait timing; however, it lowers fractal scaling (away from healthy 1/f structure) and requires attention. Here we show that interactive rhythmic auditory stimulation reestablishes healthy gait dynamics in PD patients. In the experiment, PD patients and healthy participants walked with a) no auditory stimulation, b) fixed-tempo RAS, and c) interactive rhythmic auditory stimulation. The interactive system used foot sensors and nonlinear oscillators to track and mutually entrain with the human's step timing. Patients consistently synchronized with the interactive system, their fractal scaling returned to levels of healthy participants, and their gait felt more stable to them. Patients and healthy participants rarely synchronized with fixed-tempo RAS, and when they did synchronize their fractal scaling declined from healthy 1/f levels. Five minutes after removing the interactive rhythmic stimulation, the PD patients' gait retained high fractal scaling, suggesting that the interaction stabilized the internal rhythm generating system and reintegrated timing networks. The experiment demonstrates that complex interaction is important in the (re)emergence of 1/f structure in human behavior and that interactive rhythmic auditory stimulation is a promising therapeutic tool for improving gait of PD patients.

  7. Plant-based antimicrobial studies--methods and approaches to study the interaction between natural products.

    PubMed

    van Vuuren, Sandy; Viljoen, Alvaro

    2011-07-01

    The therapeutic value of synergistic interactions has been known since antiquity, and many different cultural healing systems still rely on this principle in the belief that combination therapy may enhance efficacy. This paper intends to provide an overview, from an antimicrobial perspective, on the research undertaken and interactive principles involved in pharmacognosy studies. Methods used to determine antimicrobial interactions include basic combination studies, the sum of the fractional inhibitory concentration index (ΣFIC), isobole interpretations, and death kinetic (time-kill) assays. The various interactions are discussed with reference to molecules, different plant parts or fractions, different plant species, and combinations with nonbotanical antimicrobial agents. It is recommended for future development in the field of phytosynergy that consideration should be given to the selection criteria for the two inhibitors. A more conservative approach should be adopted when classifying synergy. When examining interactions in plant-based studies, antagonistic interactions should not be ignored. Combinations involving more than two test samples should be examined where applicable, and very importantly, the mechanism of action of synergistic interactions should be given precedence. It is encouraging to observe the upsurge in papers exploring the complex interactions of medicinal plants, and undoubtedly this will become increasingly important in our continued quest to understand the mechanism of action of phytotherapy. The scientific validation of efficacious antimicrobial combinations could lead to patentable entities making research in the field of phytosynergy not only academically rewarding but also commercially relevant.

  8. Interactions between natural-occurring landscape conditions and land use influencing the abundance of riverine smallmouth bass, micropterus dolomieu

    USGS Publications Warehouse

    Brewer, S.K.; Rabeni, C.F.

    2011-01-01

    This study examined how interactions between natural landscape features and land use influenced the abundance of smallmouth bass, Micropterus dolomieu, in Missouri, USA, streams. Stream segments were placed into one of four groups based on natural-occurring watershed characteristics (soil texture and soil permeability) predicted to relate to smallmouth bass abundance. Within each group, stream segments were assigned forest (n = 3), pasture (n = 3), or urban (n = 3) designations based on the percentages of land use within each watershed. Analyses of variance indicated smallmouth bass densities differed between land use and natural conditions. Decision tree models indicated abundance was highest in forested stream segments and lowest in urban stream segments, regardless of group designation. Land use explained the most variation in decision tree models, but in-channel features of temperature, flow, and sediment also contributed significantly. These results are unique and indicate the importance of natural-occurring watershed conditions in defining the potential of populations and how finer-scale filters interact with land use to further alter population potential. Smallmouth bass has differing vulnerabilities to land-use attributes, and the better the natural watershed conditions are for population success, the more resilient these populations will be when land conversion occurs.

  9. Spatial and temporal patterns of nature-based tourism interactions with whale sharks (Rhincodon typus) at Ningaloo Reef, Western Australia

    NASA Astrophysics Data System (ADS)

    Anderson, Douglas J.; Kobryn, Halina T.; Norman, Brad M.; Bejder, Lars; Tyne, Julian A.; Loneragan, Neil R.

    2014-07-01

    As with other nature-based tourism ventures, whale shark tourism is expanding rapidly worldwide, which highlights the need to understand more about the nature of these activities. Records of interactions between tour operators and whale sharks at Ningaloo Reef, Western Australia (22.5°S, 113.5°E) were obtained from the Western Australian Department of Parks and Wildlife from 2006 to 2010 and evaluated to determine the scale of the tourism operations and the spatial and temporal distribution of interactions. The number of whale shark tours at Ningaloo increased by approx. 70% (520-886 tours per year) and the number of interactions with whale sharks by 370% between 2006 (694) and 2010 (3254). The locations of whale shark interactions recorded in logbooks (2006-2009) and electronic monitoring systems (2009 and 2010) were used to plot the smoothed densities of tour operator interactions with whale sharks. Generalised linear models were used to investigate how the presence/absence and number of whale shark interactions at North and South Ningaloo were influenced by the distance to the reef crest, the distance to passages and their interaction terms for the aggregated five-year data set. Over the five years, distance to the reef crest was the best predictor of the presence/absence of whale shark interactions at both North (interactions concentrated within 3 km of the reef crest) and South Ningaloo (interactions within 6 km of the reef crest) followed by distance to passages. The reef passages are very significant areas for tourism interactions with whale sharks at Ningaloo. The distribution of interactions at North and South Ningaloo varied from year to year, particularly in the strong La Niña year of 2010, when average sea surface temperatures remained above 24 °C and whale sharks were observed much later in the year than previously (late August). This study demonstrates the value of the data collected by the tour operators at Ningaloo Reef and managed by a

  10. Natural Language Query System Design for Interactive Information Storage and Retrieval Systems. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Dominick, Wayne D. (Editor); Liu, I-Hsiung

    1985-01-01

    The currently developed multi-level language interfaces of information systems are generally designed for experienced users. These interfaces commonly ignore the nature and needs of the largest user group, i.e., casual users. This research identifies the importance of natural language query system research within information storage and retrieval system development; addresses the topics of developing such a query system; and finally, proposes a framework for the development of natural language query systems in order to facilitate the communication between casual users and information storage and retrieval systems.

  11. Nature of the attractive interaction between proton acceptors and organic ring systems.

    PubMed

    Arras, Emmanuel; Seitsonen, Ari Paavo; Klappenberger, Florian; Barth, Johannes V

    2012-12-14

    Systematic ab initio calculations are combined with a deconvolution of electrostatic contributions to analyze the interplay between potential hydrogen bond acceptors and organic rings with C(sp(2))-H groups (benzene, pyridine and cyclopentadiene). A distinct anisotropic interaction between the ring systems and the electron lone pairs of cyanide, water and other acceptor species is revealed that favors the in-plane orientation of the proton acceptor group. In the attractive regime this interaction carries a pronounced electrostatic signature. By decomposing the electrostatic contribution into parts attributed to different subunits of the ring systems we demonstrate that a major proportion of the interaction energy gain is originating from the non-adjacent moieties, that are not in close contact with. This behavior holds equally for homocyclic, heterocyclic and non-aromatic rings but contrasts that of the ethyne molecule, taken as reference for a weak hydrogen bond donor clearly exhibiting the expected localized character. The ring interaction requires the presence of π-electron clouds and typically results in an interaction energy gain of 40 to 80 meV. Our findings suggest the proton acceptor-ring interaction as a new category of intermolecular non-covalent interactions.

  12. Light-Induced Transformations of the C60 Derivative, Fullerenol: Interactions with Natural Organic Matter

    EPA Science Inventory

    Recent studies have indicated that fullerenes, an important class of nanomaterials, are photodegraded by solar radiation and can sensitize the photoproduction of reactive oxygen species such as singlet oxygen. Because natural organic matter (NOM) can retard photoreactions that a...

  13. Molecular dynamics simulations on the interactions of low molecular weight natural organic acids with C60.

    PubMed

    Sun, Qian; Xie, Hong-Bin; Chen, Jingwen; Li, Xuehua; Wang, Zhuang; Sheng, Lianxi

    2013-07-01

    As an important part of dissolved organic matter (DOM), low molecular weight organic acids (LOAs) may play a key role in the process for DOM stabilizing carbon nanomaterials (e.g. C60) suspensions in aquatic environment. In addition, both LOAs and C60 have been detected in the troposphere and therefore have a chance to interact with each other in the gaseous phase. However, the mechanism for LOAs-C60 interactions and their environmental implications need further investigations. In this study, molecular dynamics (MD) simulation was employed to investigate the interactions between both neutral and ionic LOAs with C60 in vacuum and water. The results showed that the adsorptions of all LOAs on C60 in energy are favorable, and the aromatic acids have stronger interactions with C60 than the aliphatic acids in vacuum and water. The interaction energies (Eint) of the LOA anions with C60 were weaker than those of their corresponding neutral LOA molecules. The models were also developed to predict and interpret Eint based on the results from MD simulations. Dispersion, induction and hydrophobic interactions were found to be the dominating factor in Eint. These findings indicate that cost-efficient MD simulation can be employed as an important tool to predict the adsorption behavior of LOAs on carbon nanomaterials.

  14. What is a 21st-century doctor? Rethinking the significance of the medical degree.

    PubMed

    Ten Cate, Olle

    2014-07-01

    The undergraduate medical degree, leading to a license to practice, has traditionally been the defining professional milestone of the physician. Developments in health care and medical education and training, however, have changed the significance of the medical degree in the continuum of education toward clinical practice. The author discusses six questions that should lead us to rethink the current status and significance of the medical degree and, consequently, that of the physician. These questions include the quest for core knowledge and competence of the doctor, the place of the degree in the education continuum, the increasing length of training, the sharing of health care tasks with other professionals, and the nature of professional identity in a multitasking world. The author concludes by examining ways to redefine what it means to be a "medical doctor."

  15. Different foraging preferences of hummingbirds on artificial and natural flowers reveal mechanisms structuring plant-pollinator interactions.

    PubMed

    Maglianesi, María A; Böhning-Gaese, Katrin; Schleuning, Matthias

    2015-05-01

    In plant-pollinator networks, the floral morphology of food plants is an important determinant of the interaction niche of pollinators. Studies on foraging preferences of pollinators combining experimental and observational approaches may help to understand the mechanisms behind patterns of interactions and niche partitioning within pollinator communities. In this study, we tested whether morphological floral traits were associated with foraging preferences of hummingbirds for artificial and natural flower types in Costa Rica. We performed field experiments with artificial feeders, differing in length and curvature of flower types, to quantify the hummingbirds' interaction niche under unlimited nectar resources. To quantify the interaction niche under real-world conditions of limited nectar resources, we measured foraging preferences of hummingbirds for a total of 34 plant species. Artificial feeders were visited by Eupherusa nigriventris and Phaethornis guy in the pre-montane forest, and Lampornis calolaemus in the lower montane forest. Under experimental conditions, all three hummingbird species overlapped their interaction niches and showed a preference for the short artificial flower type over the long-straight and the long-curved flower types. Under natural conditions, the two co-occurring hummingbird species preferred to feed on plant species with floral traits corresponding to their bill morphology. The short-billed hummingbird E. nigriventris preferred to feed on short and straight flowers, whereas the long- and curved-billed P. guy preferred long and curved natural flowers. The medium-size billed species L. calolaemus preferred to feed on flowers of medium length and did not show preferences for plant species with specific corolla curvature. Our results show that floral morphological traits constrain access by short-billed hummingbird species to nectar resources. Morphological constraints, therefore, represent one important mechanism structuring trophic

  16. Interactional nursing--a practice-theory in the dynamic field between the natural, human and social sciences.

    PubMed

    Scheel, Merry Elisabeth; Pedersen, Birthe D; Rosenkrands, Vibeke

    2008-12-01

    Nursing is often described from the point of view of either the natural or the human sciences. In contrast to this, the value foundation in Interactional nursing practice is understood from the point of view of the natural sciences as well as that of the human and social sciences. This article presents many-faceted practice-theory of nursing, which is situated in the dynamic field between these three sciences. The focus of the theory is on interaction and practice resulting in a caring practice. Here practice is based on Taylor's and MacIntyre's interpretation of this concept. Action in nursing is based on Habermas' three varied modes of action seen in the light of an understanding of the world as a system world and a life world. Nursing as an interactional practice-theory is presented with examples of interpretative nursing science, seen in the ethical action-oriented, socio-cultural framework of Taylor and Habermas. It is concluded that phenomenologic and socio-cultural research into caring practice as well as an in-depth, comprehensive interpretation of nursing practice are both highly suited to forming the fundamental theoretical framework in nursing, here seen as an interpretative nursing science. Finally, a comparison is drawn between Interactional nursing practice and Benner's theory of nursing practice.

  17. Split-ubiquitin yeast two-hybrid interaction reveals a novel interaction between a natural resistance associated macrophage protein and a membrane bound thioredoxin in Brassica juncea.

    PubMed

    Marik, Ananya; Naiya, Haraprasad; Das, Madhumanti; Mukherjee, Gairik; Basu, Soumalee; Saha, Chinmay; Chowdhury, Rajdeep; Bhattacharyya, Kankan; Seal, Anindita

    2016-11-01

    Natural resistance associated macrophage proteins (NRAMPs) are evolutionarily conserved metal transporters involved in the transport of essential and nonessential metals in plants. Fifty protein interactors of a Brassica juncea NRAMP protein was identified by a Split-Ubiquitin Yeast-Two-Hybrid screen. The interactors were predicted to function as components of stress response, signaling, development, RNA binding and processing. BjNRAMP4.1 interactors were particularly enriched in proteins taking part in photosynthetic or light regulated processes, or proteins predicted to be localized in plastid/chloroplast. Further, many interactors also had a suggested role in cellular redox regulation. Among these, the interaction of a photosynthesis-related thioredoxin, homologous to Arabidopsis HCF164 (High-chlorophyll fluorescence164) was studied in detail. Homology modeling of BjNRAMP4.1 suggested that it could be redox regulated by BjHCF164. In yeast, the interaction between the two proteins was found to increase in response to metal deficiency; Mn excess and exogenous thiol. Excess Mn also increased the interaction in planta and led to greater accumulation of the complex at the root apoplast. Network analysis of Arabidopsis homologs of BjNRAMP4.1 interactors showed enrichment of many protein components, central to chloroplastic/cellular ROS signaling. BjNRAMP4.1 interacted with BjHCF164 at the root membrane and also in the chloroplast in accordance with its proposed function related to photosynthesis, indicating that this interaction occurred at different sub-cellular locations depending on the tissue. This may serve as a link between metal homeostasis and chloroplastic/cellular ROS through protein-protein interaction.

  18. Effect of the nature of phospholipids on the degree of their interaction with isobornylphenol antioxidants

    NASA Astrophysics Data System (ADS)

    Marakulina, K. M.; Kramor, R. V.; Lukanina, Yu. K.; Plashchina, I. G.; Polyakov, A. V.; Fedorova, I. V.; Chukicheva, I. Yu.; Kutchin, A. V.; Shishkina, L. N.

    2016-02-01

    The parameters of complexation between natural phospholipids (lecithin, sphingomyelin, and cephalin) with antioxidants of a new class, isobornylphenols (IBPs), were determined by UV and IR spectroscopy. The self-organization of phospholipids (PLs) was studied depending on the structure of IBPs by dynamic light scattering. The nature of phospholipids and the structure of IBPs was found to produce a substantial effect both on the degree of complexation and on the size of PL aggregates in a nonpolar solvent. Based on the obtained data it was concluded that the structure of biological membranes mainly depends on the complexation of IBP with sphingomyelin.

  19. Nature of soliton interaction in fiber lasers with continuous external optical injection

    NASA Astrophysics Data System (ADS)

    Komarov, Andrey; Komarov, Konstantin; Niang, Alioune; Sanchez, François

    2014-01-01

    It has been shown by numerical simulation that the nonlinear interaction between a laser soliton and an injected monochromatic cw results in their phase locking. As a consequence, the velocity of the soliton begins to depend on the amplitude and frequency of the injected radiation. It has been found that if the frequency of the external signal coincides with the frequency of the dispersive waves emitted by solitons in a laser cavity with lumped intracavity elements, a mechanism for controlling long-range soliton interaction occurs. This mechanism is related to the interference between the injected wave and the dispersive waves involved in the strong long-range interaction between solitons. We have demonstrated the mechanism of soliton-soliton repulsion and, as its consequence, the occurrence of harmonic passive mode locking (multipulse generation with an equidistant arrangement of identical solitons in the laser cavity).

  20. Representing Nature of Science in a Science Textbook: Exploring Author-Editor-Publisher Interactions

    ERIC Educational Resources Information Center

    DiGiuseppe, Maurice

    2014-01-01

    Current reforms in elementary and secondary science education call for students and teachers to develop more informed views of the nature of science (NOS)--a process in which science textbooks play a significant role. This paper reports on a case study of the development of representations of the NOS in a senior high school chemistry textbook by…

  1. A Tutoring System That Simulates the Highly Interactive Nature of Human Tutoring

    ERIC Educational Resources Information Center

    Katz, Sandra; Albacete, Patricia L.

    2013-01-01

    For some time, it has been clear that students who are tutored generally learn more than students who experience classroom instruction (e.g., Bloom, 1984). Much research has been devoted to identifying features of tutorial dialogue that can explain its effectiveness, so that these features can be simulated in natural-language tutoring systems. One…

  2. Self-Report Data on the Interactive Nature of Stress in Canadian Elementary School Principals.

    ERIC Educational Resources Information Center

    McMurray, J. G.

    Stress has been defined as a stimulus event, a complex personal response to the interaction of various personal and environmental factors. When a demand, real or imagined, is perceived, a stress response will occur unless appropriate coping responses are present. The terms burnout or excessive distress refer to the experience of physical,…

  3. Interactions of Graphene Oxide Nanomaterials with Natural Organic Matter and Metal Oxide Surfaces

    EPA Science Inventory

    Interactions of graphene oxide (GO) with silica surfaces were investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D). Both GO deposition and release were monitored on silica- and poly-l-lysine (PLL) coated surfaces as a function of GO concentration a...

  4. Physical nature of ethidium and proflavine interactions with nucleic acid bases in the intercalation plane.

    PubMed

    Langner, Karol M; Kedzierski, Pawel; Sokalski, W Andrzej; Leszczynski, Jerzy

    2006-05-18

    On the basis of the crystallographic structures of three nucleic acid intercalation complexes involving ethidium and proflavine, we have analyzed the interaction energies between intercalator chromophores and their four nearest bases, using a hybrid variation-perturbation method at the second-order Møller-Plesset theory level (MP2) with a 6-31G(d,p) basis set. A total MP2 interaction energy minimum precisely reproduces the crystallographic position of the ethidium chromophore in the intercalation plane between UA/AU bases. The electrostatic component constitutes the same fraction of the total energy for all three studied structures. The multipole electrostatic interaction energy, calculated from cumulative atomic multipole moments (CAMMs), was found to converge only after including components above the fifth order. CAMM interaction surfaces, calculated on grids in the intercalation planes of these structures, reasonably reproduce the alignment of intercalators in crystal structures; they exhibit additional minima in the direction of the DNA grooves, however, which also need to be examined at higher theory levels if no crystallographic data are given.

  5. The Use of Interactive Whiteboards: Enhancing the Nature of Teaching Young Language Learners

    ERIC Educational Resources Information Center

    Giannikas, Christina Nicole

    2016-01-01

    Language teaching can be enhanced by effective uses of technology; nonetheless, there are teachers who are reluctant to integrate technology in their practice. The debated issue has resulted in a number of Ministries of Education worldwide, including the Greek Ministry, to support a transition through the introduction of Interactive Whiteboards…

  6. NATURE OF BINDING INTERACTION OF SELECTED CHEMICALS WITH RAT ESTROGEN RECEPTORS

    EPA Science Inventory

    The US EPA is currently validating a rat uterine estrogen receptor (ER) binding assay as part of the Tier 1 Screening Battery for the Endocrine Disruptor Program. An eventual goal is to use interactive data to create computerized structure-activity models. However, more informati...

  7. Natural gas storage - end user interaction. Final report, September 1992--May 1996

    SciTech Connect

    1998-12-31

    The primary purpose of this project is to develop an understanding of the market for natural gas storage that will provide for rigorous evaluation of federal research and development opportunities in storage technologies. The project objectives are: (1) to identify market areas and end use sectors where new natural gas underground storage capacity can be economically employed; (2) to develop a storage evaluation system that will provide the analytical tool to evaluate storage requirements under alternate economic, technology, and market conditions; and (3) to analyze the economic and technical feasibility of alternatives to conventional gas storage. An analytical approach was designed to examine storage need and economics on a total U.S. gas system basis, focusing on technical and market issues. Major findings of each subtask are reported in detail. 79 figs.

  8. Rethinking the Study of Volition for Clinical Use.

    PubMed

    Torres, Elizabeth B

    2016-01-01

    Volition, the acquired voluntary control of our actions (at will), requires from birth to development and beyond a proper balance across multiple layers of the nervous systems. These levels range from the autonomic, to the automatic, to the voluntary control level, providing as well taxonomy with phylogenetic order of appearance in evolution. In the past few decades of movement research at the behavioral and systems levels, there has been a paucity of studies focusing on the possible contributions of involuntary movements to volitional control. Moreover, the work focusing on voluntary behavior has given us a valuable body of knowledge about constrained and highly over practiced activities while work involving unrestrained, naturalistic behaviors remains scarce. Perhaps in making theoretical assumptions about our data acquisition and analyses without properly empirically verifying, these assumptions have left us with a somewhat skewed notion of how we think the brain may be realizing the neural control of bodily motions; a notion that does not exactly correspond to the outcome of the extant empirical work assessing unrestrained movements as the nervous system acquires them and modifies skillful behaviors on demand. This chapter takes advantage of new technological advances and new analytics to invite rethinking some of the problems that we study in movement science by enforcing somewhat oversimplified assumptions on the data that we model, acquire, and analyze. I show that by relaxing our a priori assumptions of normality, linearity and stationarity in data from biophysical rhythms of the nervous systems, we would gain better insights into the motor phenomena. Further, we would shy away from a "self-fulfilling prophesy" paradigm with a tendency to a priori handcraft the outcome of our inquiry. The new lens to study natural movements and their control includes as well involuntary motions that take place largely beneath deliberate awareness. I present examples of

  9. Rethinking dry eye disease: a perspective on clinical implications.

    PubMed

    Bron, Anthony J; Tomlinson, Alan; Foulks, Gary N; Pepose, Jay S; Baudouin, Christophe; Geerling, Gerd; Nichols, Kelly K; Lemp, Michael A

    2014-04-01

    Publication of the DEWS report in 2007 established the state of the science of dry eye disease (DED). Since that time, new evidence suggests that a rethinking of traditional concepts of dry eye disease is in order. Specifically, new evidence on the epidemiology of the disease, as well as strategies for diagnosis, have changed the understanding of DED, which is a heterogeneous disease associated with considerable variability in presentation. These advances, along with implications for clinical care, are summarized herein. The most widely used signs of DED are poorly correlated with each other and with symptoms. While symptoms are thought to be characteristic of DED, recent studies have shown that less than 60% of subjects with other objective evidence of DED are symptomatic. Thus the use of symptoms alone in diagnosis will likely result in missing a significant percentage of DED patients, particularly with early/mild disease. This could have considerable impact in patients undergoing cataract or refractive surgery as patients with DED have less than optimal visual results. The most widely used objective signs for diagnosing DED all show greater variability between eyes and in the same eye over time compared with normal subjects. This variability is thought to be a manifestation of tear film instability which results in rapid breakup of the tearfilm between blinks and is an identifier of patients with DED. This feature emphasizes the bilateral nature of the disease in most subjects not suffering from unilateral lid or other unilateral destabilizing surface disorders. Instability of the composition of the tears also occurs in dry eye disease and shows the same variance between eyes. Finally, elevated tear osmolarity has been reported to be a global marker (present in both subtypes of the disease- aqueous-deficient dry eye and evaporative dry eye). Clinically, osmolarity has been shown to be the best single metric for diagnosis of DED and is directly related to

  10. Multitrophic interactions involving genetically modified potatoes, nontarget aphids, natural enemies and hyperparasitoids.

    PubMed

    Cowgill, S E; Danks, C; Atkinson, H J

    2004-03-01

    Genetically modified (GM) potatoes expressing a cysteine proteinase inhibitor (cystatin) have been developed as an option for the management of plant parasitic nematodes. The relative impact of such plants on predators and parasitoids (natural enemies) of nontarget insects was determined in a field trial. The trial consisted of GM plants, control plants grown in soil treated with a nematicide and untreated control plants. The quantity of nontarget aphids and their quality as hosts for natural enemies were studied. Aphid density was significantly reduced by nematicide treatment and few natural enemies were recorded from treated potatoes during the study. In contrast, similar numbers of aphids and their more abundant predators were recorded from the untreated control and the GM potatoes. The size of aphids on GM and control plants was recorded twice during the study. During the first sampling period (2-9 July) aphids clip-caged on GM plants were smaller than those on control plants. During the second sampling period (23-30 July) there was no difference in aphid size between those from the GM and control plants. Host size is an important component of host quality. It can affect the size and fecundity of parasitoid females and the sex ratio of their offspring. However, neither the fitness of females of Aphidius ervi, the most prevalent primary parasitoid, nor the sex ratio of their progeny, were affected when the parasitoids developed on aphids feeding on GM plants. Two guilds of secondary parasitoid were also recorded during the study. The fitness of the most abundant species, Aspahes vulgaris, was not affected when it developed on hosts from GM plants. The transgene product, OC I Delta D86, was not detected in aphids that had fed on GM plants in the field, suggesting that there is minimal secondary exposure of natural enemies to the inhibitor. The results indicate that transgenic nematode resistance is potentially more compatible with aphid biological control than is

  11. Natural asynchronies in audiovisual communication signals regulate neuronal multisensory interactions in voice-sensitive cortex

    PubMed Central

    Perrodin, Catherine; Kayser, Christoph; Logothetis, Nikos K.; Petkov, Christopher I.

    2015-01-01

    When social animals communicate, the onset of informative content in one modality varies considerably relative to the other, such as when visual orofacial movements precede a vocalization. These naturally occurring asynchronies do not disrupt intelligibility or perceptual coherence. However, they occur on time scales where they likely affect integrative neuronal activity in ways that have remained unclear, especially for hierarchically downstream regions in which neurons exhibit temporally imprecise but highly selective responses to communication signals. To address this, we exploited naturally occurring face- and voice-onset asynchronies in primate vocalizations. Using these as stimuli we recorded cortical oscillations and neuronal spiking responses from functional MRI (fMRI)-localized voice-sensitive cortex in the anterior temporal lobe of macaques. We show that the onset of the visual face stimulus resets the phase of low-frequency oscillations, and that the face–voice asynchrony affects the prominence of two key types of neuronal multisensory responses: enhancement or suppression. Our findings show a three-way association between temporal delays in audiovisual communication signals, phase-resetting of ongoing oscillations, and the sign of multisensory responses. The results reveal how natural onset asynchronies in cross-sensory inputs regulate network oscillations and neuronal excitability in the voice-sensitive cortex of macaques, a suggested animal model for human voice areas. These findings also advance predictions on the impact of multisensory input on neuronal processes in face areas and other brain regions. PMID:25535356

  12. Natural asynchronies in audiovisual communication signals regulate neuronal multisensory interactions in voice-sensitive cortex.

    PubMed

    Perrodin, Catherine; Kayser, Christoph; Logothetis, Nikos K; Petkov, Christopher I

    2015-01-06

    When social animals communicate, the onset of informative content in one modality varies considerably relative to the other, such as when visual orofacial movements precede a vocalization. These naturally occurring asynchronies do not disrupt intelligibility or perceptual coherence. However, they occur on time scales where they likely affect integrative neuronal activity in ways that have remained unclear, especially for hierarchically downstream regions in which neurons exhibit temporally imprecise but highly selective responses to communication signals. To address this, we exploited naturally occurring face- and voice-onset asynchronies in primate vocalizations. Using these as stimuli we recorded cortical oscillations and neuronal spiking responses from functional MRI (fMRI)-localized voice-sensitive cortex in the anterior temporal lobe of macaques. We show that the onset of the visual face stimulus resets the phase of low-frequency oscillations, and that the face-voice asynchrony affects the prominence of two key types of neuronal multisensory responses: enhancement or suppression. Our findings show a three-way association between temporal delays in audiovisual communication signals, phase-resetting of ongoing oscillations, and the sign of multisensory responses. The results reveal how natural onset asynchronies in cross-sensory inputs regulate network oscillations and neuronal excitability in the voice-sensitive cortex of macaques, a suggested animal model for human voice areas. These findings also advance predictions on the impact of multisensory input on neuronal processes in face areas and other brain regions.

  13. Competitive interactions and controlled release of a natural antioxidant from halloysite nanotubes.

    PubMed

    Hári, József; Gyürki, Ádám; Sárközi, Márk; Földes, Enikő; Pukánszky, Béla

    2016-01-15

    Halloysite nanotubes used as potential carrier material for a controlled release stabilizer in polyethylene were thoroughly characterized with several techniques including the measurement of specific surface area, pore volume and surface energy. The high surface energy of the halloysite results in the strong bonding of the additive to the surface. Dissolution experiments carried out with eight different solvents for the determination of the effect of solvent characteristics on the amount of irreversibly bonded quercetin proved that adsorption and dissolution depend on competitive interactions prevailing in the system. Solvents with low polarity dissolve only surplus quercetin adsorbed in multilayers. Polyethylene is a very apolar polymer forming weak interactions with every substance; quercetin dissolves into it from the halloysite surface only above a critical surface coverage. Stabilization experiments confirmed that strong adhesion prevents dissolution and results in limited stabilization efficiency. At larger adsorbed amounts better stability and extended effect were measured indicating dissolution and controlled release.

  14. Fluorescence spectroscopy as a specific tool for the interaction study of two surfactants with natural and synthetic organic compounds

    NASA Astrophysics Data System (ADS)

    Jung, Aude-Valérie; Frochot, Céline; Bersillon, Jean-Luc

    2016-04-01

    Four different techniques were used to study the binding of cationic cetyltrimethylammonium bromide (CTAB) and non-ionic nonylphenylethoxyl (NPE) surfactants to three synthetic organic components that mimic humic-like aggregates and to two natural aggregated humic substances (HS) extracted from aquatic suspended matter. The composition of synthetic organic components were chosen to be similar to high molecular weight highly processed terrigenous HS and low and high molecular weight less processed terrigenous (or aquatic terrigenous) HS. The natural HS were extracted under two different meteorological conditions (rainy and dry periods). No significant interaction between the non-ionic surfactant and any of the studied compounds was found. Concerning CTAB; pH, conductivity and turbidity measurements, along with fluorescence spectroscopy were combined to provide a better understanding of interactions between organic aggregates and the surfactant. The spectroscopic data show that a "highly processed terrigenous HS" fluorophore interacts in a different way with the cationic surfactant than an "aquatic terrigenous (or less processed terrigenous) HS" fluorophore does. Under similar conditions, some spectral changes in the fluorescence signal are correlated to changes in non-specific physical-chemical parameters (pH, turbidity, conductivity) for the organic compounds tested. The complexation mechanism is essentially governed by charge neutralization, which can be monitored specifically by the fluorescence of the organic moieties.

  15. Rethinking Soils: an under-investigated commons?

    NASA Astrophysics Data System (ADS)

    Short, Chrisopher; Mills, Jane; Ingram, Julie

    2015-04-01

    category of ecosystem services. As a result of the increasing evidence regarding soil threats, there is concern that the knowledge relating to soils is fragmented and incomplete. This is particular true regarding the complexity and functioning of soil systems and their interaction with human activities and the effectiveness of governance arrangements to promote resilience in the management of soils. Therefore discussions concerning soils needs to be taken from an interdisciplinary perspectives that embraces both natural and social sciences. This paper will seek to examine soils from a multi-scale governance/complex commons perspective. It will also consider how a commons perspective might be useful in reducing soil threats and in the development of effective prevention, remediation and restoration measures. This often requires a change in thinking about soil, perhaps considering it as a 'slow variable', able to drive long-term change or as a 'cultural asset' and 'knowledge resource'.

  16. Rethinking Management Education for the 21st Century. Research in Management Education and Development.

    ERIC Educational Resources Information Center

    Wankel, Charles, Ed.; DeFillippi, Robert, Ed.

    This book series focuses on trends in theory and practice likely to influence 21st century management education. This first volume examines a series of innovative and distinctive approaches to rethinking management education for the 21st century. Part 1 of the collection, "Rethinking What We Teach," contains: (1) "Development of Political Skill"…

  17. Feet to the Fire: New Orleans Kids Rethink Their Devastated School System

    ERIC Educational Resources Information Center

    Wholey, Jane; Burkes, Betty

    2015-01-01

    Kids Rethink New Orleans Schools is an organization of primarily middle school youth that formed after Hurricane Katrina destroyed most of the city's schools. This chapter describes Rethink's first six years of operation, which culminated in school system policy changes and an HBO documentary about the organization's groundbreaking work.

  18. Airborne Next: Rethinking Airborne Organization and Applying New Concepts

    DTIC Science & Technology

    2015-06-01

    structures since its employment on a large scale during World War II. It is puzzling to consider how little airborne organizational structures and employment...future potential of airborne concepts by rethinking traditional airborne organizational structures and employment concepts. Using a holistic approach in... structures of airborne forces to model a “small and many” approach over a “large and few” approach, while incorporating a “swarming” concept. Utilizing

  19. Of spheres and squares: Can Sloterdijk help us rethink the architecture of climate science?

    PubMed

    Skrydstrup, Martin

    2016-12-01

    This article explores how different visions and values of science translate into different architectural shapes. I bring Peter Sloterdijk's 'spherology' to bear on my ethnographic fieldwork at the NEEM ice core base in Greenland, a significant node in the global infrastructure of climate science. I argue that the visual form of the geodesic dome of the camp materializes specific values and visions of this branch of paleoclimate science, which I elaborate vis-a-vis the pragmatic claims of the scientists/designers and the particular architectural history of Danish ice core drilling in Greenland. I argue that this aesthetic history articulates with Buckminster Fuller's ideas of a 'new nature' and 'scalar connections' encapsulated in his geodesic form. Second, I argue that the aesthetic production of space in the camp replicates the modern distinction between science and society, in so far as the lab space is rectangular and the recreational space is spherical. Third, I argue that NEEM scientists and Sloterdijk are essentially engaged in a common project: the scientists work hard to align air bubbles in the cores with atmospheric fluctuations in the hemisphere on the evidentiary terrain of ice, and Sloterdijk attempts to connect micro-uteri with macro-uteri in an attempt to fundamentally rethink space. Fuller's notion of 'Spaceship Earth', appropriated by Sloterdijk in his thinking about anthropogenic climate change, lends itself well to capturing the scalar alignments and the isolated NEEM base - on a mission to save planet Earth. In conclusion, I argue that Sloterdijk's spherology may serve as a point of departure for rethinking the aesthetic grammar of the architecture of science.

  20. Computational analysis of stacking interactions between 3-nitropyrrole and natural nucleobases.

    PubMed

    Ukawa, Hisashi; Seio, Kohji; Sekine, Mitsuo

    2002-01-01

    The stacking energies between natural nucleobases and a universal base of 3-nitropyrrole (3-NP) were calculated by use of two theoretically independent quantum chemical methods, namely, molecular orbital (MO) and density function theory (DFT) calculations. The parameters required for molecular mechanics calculation of 3-NP were obtained by use of a software of Direct Force Field and used to evaluate the stacking energy of the complexes formed between 3-NP and canonical four nucleobases. Dependence of the twist angle between the two stacked bases on the stacking energy was studied in great detail.

  1. Pyridine and phenol removal using natural and synthetic apatites as low cost sorbents: influence of porosity and surface interactions.

    PubMed

    Bouyarmane, H; El Asri, S; Rami, A; Roux, C; Mahly, M A; Saoiabi, A; Coradin, T; Laghzizil, A

    2010-09-15

    A natural phosphate rock and two synthetic mesoporous hydroxyapatites were evaluated for the removal of pyridine and phenol from aqueous solutions. Experiments performed by the batch method showed that the sorption process occurs by a first order reaction for both pyridine and phenol. In contrast, the Freundlich model was able to describe sorption isotherms for phenol but not for pyridine. In parallel, the three apatites exhibit similar pyridine sorption capacities whereas phenol loading was in agreement with their respective specific surface area. This was attributed to the strong interaction arising between pyridine and apatite surface that hinders further inter-particular diffusion. This study suggests that, despite its low specific surface area, natural phosphate rock may be used as an efficient sorbent material for specific organic pollutants, with comparable efficiency and lower processing costs than some activated carbons.

  2. Overlapping Yet Response-Specific Transcriptome Alterations Characterize the Nature of Tobacco–Pseudomonas syringae Interactions

    PubMed Central

    Bozsó, Zoltán; Ott, Péter G.; Kámán-Tóth, Evelin; Bognár, Gábor F.; Pogány, Miklós; Szatmári, Ágnes

    2016-01-01

    In this study transcriptomic alterations of bacterially induced pattern triggered immunity (PTI) were compared with other types of tobacco–Pseudomonas interactions. In addition, using pharmacological agents we blocked some signal transduction pathways (Ca2+ influx, kinases, phospholipases, proteasomic protein degradation) to find out how they contribute to gene expression during PTI. PTI is the first defense response of plant cells to microbes, elicited by their widely conserved molecular patterns. Tobacco is an important model of Solanaceae to study resistance responses, including defense mechanisms against bacteria. In spite of these facts the transcription regulation of tobacco genes during different types of plant bacterial interactions is not well-described. In this paper we compared the tobacco transcriptomic alterations in microarray experiments induced by (i) PTI inducer Pseudomonas syringae pv. syringae type III secretion mutant (hrcC) at earlier (6 h post inoculation) and later (48 hpi) stages of defense, (ii) wild type P. syringae (6 hpi) that causes effector triggered immunity (ETI) and cell death (HR), and (iii) disease-causing P. syringae pv. tabaci (6 hpi). Among the different treatments the highest overlap was between the PTI and ETI at 6 hpi, however, there were groups of genes with specifically altered activity for either type of defenses. Instead of quantitative effects of the virulent P. tabaci on PTI-related genes it influenced transcription qualitatively and blocked the expression changes of a special set of genes including ones involved in signal transduction and transcription regulation. P. tabaci specifically activated or repressed other groups of genes seemingly not related to either PTI or ETI. Kinase and phospholipase A inhibitors had highest impacts on the PTI response and effects of these signal inhibitors on transcription greatly overlapped. Remarkable interactions of phospholipase C-related pathways with the proteasomal system were

  3. RoboFish: increased acceptance of interactive robotic fish with realistic eyes and natural motion patterns by live Trinidadian guppies.

    PubMed

    Landgraf, Tim; Bierbach, David; Nguyen, Hai; Muggelberg, Nadine; Romanczuk, Pawel; Krause, Jens

    2016-01-12

    In recent years, simple biomimetic robots have been increasingly used in biological studies to investigate social behavior, for example collective movement. Nevertheless, a big challenge in developing biomimetic robots is the acceptance of the robotic agents by live animals. In this contribution, we describe our recent advances with regard to the acceptance of our biomimetic RoboFish by live Trinidadian guppies (Poecilia reticulata). We provide a detailed technical description of the RoboFish system and show the effect of different appearance, motion patterns and interaction modes on the acceptance of the artificial fish replica. Our results indicate that realistic eye dummies along with natural motion patterns significantly improve the acceptance level of the RoboFish. Through the interactive behaviors, our system can be adjusted to imitate different individual characteristics of live animals, which further increases the bandwidth of possible applications of our RoboFish for the study of animal behavior.

  4. Nature of bonding in group 13 dimetallenes: a delicate balance between singlet diradical character and closed shell interactions.

    PubMed

    Moilanen, Jani; Power, Philip P; Tuononen, Heikki M

    2010-12-06

    The nature of metal-metal bonding in group 13 dimetallenes REER (E = Al, Ga, In, Tl; R = H, Me, (t)Bu, Ph) was investigated by use of quantum chemical methods that include HF, second order Møller-Plesset perturbation theory (MP2), coupled cluster (CCSD(T)), complete active space with (CASPT2) and without (CAS) second order perturbation theory, and two density functionals, namely, B3LYP and M06-2X. The results show that the metal-metal interaction in group 13 dimetallenes stems almost exclusively from static and dynamic electron correlation effects: both dialuminenes and digallenes have an important singlet diradical component in their wave function, whereas the bonding in the heavier diindenes and, in particular, dithallenes is dominated by closed shell metallophilic interactions. The reported calculations represent a systematic attempt to determine the metal and ligand dependent bonding changes in these systems.

  5. Solar ultraviolet-B radiation affects plant-insect interactions in a natural ecosystem of Tierra del Fuego (southern Argentina).

    PubMed

    Rousseaux, M Cecilia; Ballaré, Carlos L; Scopel, Ana L; Searles, Peter S; Caldwell, Martyn M

    1998-10-01

    We examined the effects of solar ultraviolet-B radiation (UVB) on plant-herbivore interactions in native ecosystems of the Tierra del Fuego National Park (southern Argentina), an area of the globe that is frequently under the Antarctic "ozone hole" in early spring. We found that filtering out solar UVB from the sunlight received by naturally-occurring plants of Gunnera magellanica, a creeping perennial herb, significantly increased the number of leaf lesions caused by chewing insects. Field surveys suggested that early-season herbivory was principally due to the activity of moth larvae (Lepidoptera: Noctuidae). Manipulative field experiments showed that exposure to solar UVB changes the attractiveness of G. magellanica leaf tissue to natural grazers. In a laboratory experiment, locally caught moth caterpillars tended to eat more tissue from leaves grown without UVB than from leaves exposed to natural UVB during development; however, the difference between treatments was not significant. Leaves grown under solar UVB had slightly higher N levels than leaves not exposed to UVB; no differences between UVB treatments in specific leaf mass, relative water content, and total methanol-soluble phenolics were detected. Our results show that insect herbivory in a natural ecosystem is influenced by solar UVB, and that this influence could not be predicted from crude measurements of leaf physical and chemical characteristics and a common laboratory bioassay.

  6. Rethinking mental health: a European WHO perspective

    PubMed Central

    RUTZ, WOLFGANG

    2003-01-01

    In spite of recent clinical and research advances, an increased burden of mortality and morbidity related to stress and mental ill health can be noted, especially in European societies and populations undergoing stressful transitions and dramatic changes. A societal syndrome, consisting of depression, suicide, abuse, risk-taking and violent behaviour as well as vascular morbidity and mortality, can be observed, reflecting individual psychopathology related to disturbances of the serotonin metabolism as one of the oldest, most basic cerebral instruments of mankind to survive, to socialize, to cope with stress and danger. In a time where mental health professionals look for new and challenging identities, they have a tendency to abdicate from social psychiatric and public health activities in favour of more prestigious positions in brain research, genetics or advanced psychotherapy. A redefinition, reconceptualization and renaissance of social psychiatry seems timely and necessary, responding to the burden, advances and possibilities related to mental health we find today. It should proceed from the reductionism which often has characterized earlier psychosocial and social psychiatric approaches, utilize modern knowledge about neuroplasticity, psychoimmunology, neuropsychology and neurophilosophy, reflect the interaction between environment and structure, nature and nurture, and integrate different areas of knowledge in a holistic public mental health approach. Political decisions and societal solutions can be more or less in line with basic human preconditions. Consequences of failure to respect this already can be seen. A new awareness and responsibility-taking with regard to basic human ethological, physiological, psychological and existential conditions is needed and has to be concretized in innovative public mental health approaches. PMID:16946915

  7. Climate Change and Tritrophic Interactions: Will Modifications to Greenhouse Gas Emissions Increase the Vulnerability of Herbivorous Insects to Natural Enemies?

    PubMed

    Boullis, Antoine; Francis, Frederic; Verheggen, François J

    2015-04-01

    Insects are highly dependent on odor cues released into the environment to locate conspecifics or food sources. This mechanism is particularly important for insect predators that rely on kairomones released by their prey to detect them. In the context of climate change and, more specifically, modifications in the gas composition of the atmosphere, chemical communication-mediating interactions between phytophagous insect pests, their host plants, and their natural enemies is likely to be impacted. Several reports have indicated that modifications to plants caused by elevated carbon dioxide and ozone concentrations might indirectly affect insect herbivores, with community-level modifications to this group potentially having an indirect influence on higher trophic levels. The vulnerability of agricultural insect pests toward their natural enemies under elevated greenhouse gases concentrations has been frequently reported, but conflicting results have been obtained. This literature review shows that the higher levels of carbon dioxide, as predicted for the coming century, do not enhance the abundance or efficiency of natural enemies to locate hosts or prey in most published studies. Increased ozone levels lead to modifications in herbivore-induced volatile organic compounds (VOCs) released by damaged plants, which may impact the attractiveness of these herbivores to the third trophic level. Furthermore, other oxidative gases (such as SO2 and NO2) tend to reduce the abundance of natural enemies. The impact of changes in atmospheric gas emissions on plant-insect and insect-insect chemical communication has been under-documented, despite the significance of these mechanisms in tritrophic interactions. We conclude by suggesting some further prospects on this topic of research yet to be investigated.

  8. Interactions between natural killer cells, cortisol and prolactin in malaria during pregnancy.

    PubMed

    Mavoungou, Elie

    2006-03-01

    Natural killer cells derived from pluripotent hematopoietic stem cells are important cells of the immune system that have two main functions: a cytolytic activity and a cytokine-producing capacity. These functions are tightly regulated by numerous activating and inhibitory receptors, including newly discovered receptors that selectively trigger the cytolytic activity in a major histocompatibility complex independent manner. Based on their defining function of spontaneous cytotoxicity without prior immunization, natural killer (NK) cells have been thought to play a critical role in immune surveillance and cancer therapy. New insights into NK cell biology have suggested their major roles in the control of infections, particularly in Plasmodium falciparum infection and in fetal implantation. P. falciparum is the main protozoan parasite responsible for malaria causing 200-300 million clinical cases and killing over 3 million people each year. This review provides an update on NK cell function, ontogeny and biology in order to better understand the role of NK cells in pregnancy in regions where malaria is endemic. Understanding mechanisms of NK cell functions may lead to novel therapeutic strategies for the treatment of human disease, in general, and particularly in the fight against malaria.

  9. The Mechanisms of Natural Variability and its Interaction with Anthropogenic Climate Change Final Report

    SciTech Connect

    Vallis, Geoffrey K.

    2015-01-30

    The project had two main components. The first concerns estimating the climate sensitivity in the presence of forcing uncertainty and natural variability. Climate sensitivity is the increase in the average surface temperature for a given increase in greenhouse gases, for example a doubling of carbon dioxide. We have provided new, probabilistic estimates of climate sensitivity using a simple climate model an the observed warming in the 20th century, in conjunction with ideas in data assimilation and parameter estimation developed in the engineering community. The estimates combine the uncertainty in the anthropogenic aerosols with the uncertainty arising because of natural variability. The second component concerns how the atmospheric circulation itself might change with anthropogenic global warming. We have shown that GCMs robustly predict an increase in the length scale of eddies, and we have also explored the dynamical mechanisms whereby there might be a shift in the latitude of the jet stream associated with anthropogenic warming. Such shifts in the jet might cause large changes in regional climate, potentially larger than the globally-averaged signal itself. We have also shown that the tropopause robustly increases in height with global warming, and that the Hadley Cell expands, and that the expansion of the Hadley Cell is correlated with the polewards movement of the mid-latitude jet.

  10. Early reversal cells in adult human bone remodeling: osteoblastic nature, catabolic functions and interactions with osteoclasts.

    PubMed

    Abdelgawad, Mohamed Essameldin; Delaisse, Jean-Marie; Hinge, Maja; Jensen, Pia Rosgaard; Alnaimi, Ragad Walid; Rolighed, Lars; Engelholm, Lars H; Marcussen, Niels; Andersen, Thomas Levin

    2016-06-01

    The mechanism coupling bone resorption and formation is a burning question that remains incompletely answered through the current investigations on osteoclasts and osteoblasts. An attractive hypothesis is that the reversal cells are likely mediators of this coupling. Their nature is a big matter of debate. The present study performed on human cancellous bone is the first one combining in situ hybridization and immunohistochemistry to demonstrate their osteoblastic nature. It shows that the Runx2 and CD56 immunoreactive reversal cells appear to take up TRAcP released by neighboring osteoclasts. Earlier preclinical studies indicate that reversal cells degrade the organic matrix left behind by the osteoclasts and that this degradation is crucial for the initiation of the subsequent bone formation. To our knowledge, this study is the first addressing these catabolic activities in adult human bone through electron microscopy and analysis of molecular markers. Periosteoclastic reversal cells show direct contacts with the osteoclasts and with the demineralized resorption debris. These early reversal cells show (1) ¾-collagen fragments typically generated by extracellular collagenases of the MMP family, (2) MMP-13 (collagenase-3) and (3) the endocytic collagen receptor uPARAP/Endo180. The prevalence of these markers was lower in the later reversal cells, which are located near the osteoid surfaces and morphologically resemble mature bone-forming osteoblasts. In conclusion, this study demonstrates that reversal cells colonizing bone surfaces right after resorption are osteoblast-lineage cells, and extends to adult human bone remodeling their role in rendering eroded surfaces osteogenic.

  11. Psychomotor impairment detection via finger interactions with a computer keyboard during natural typing.

    PubMed

    Giancardo, L; Sánchez-Ferro, A; Butterworth, I; Mendoza, C S; Hooker, J M

    2015-04-16

    Modern digital devices and appliances are capable of monitoring the timing of button presses, or finger interactions in general, with a sub-millisecond accuracy. However, the massive amount of high resolution temporal information that these devices could collect is currently being discarded. Multiple studies have shown that the act of pressing a button triggers well defined brain areas which are known to be affected by motor-compromised conditions. In this study, we demonstrate that the daily interaction with a computer keyboard can be employed as means to observe and potentially quantify psychomotor impairment. We induced a psychomotor impairment via a sleep inertia paradigm in 14 healthy subjects, which is detected by our classifier with an Area Under the ROC Curve (AUC) of 0.93/0.91. The detection relies on novel features derived from key-hold times acquired on standard computer keyboards during an uncontrolled typing task. These features correlate with the progression to psychomotor impairment (p < 0.001) regardless of the content and language of the text typed, and perform consistently with different keyboards. The ability to acquire longitudinal measurements of subtle motor changes from a digital device without altering its functionality may allow for early screening and follow-up of motor-compromised neurodegenerative conditions, psychological disorders or intoxication at a negligible cost in the general population.

  12. Psychomotor Impairment Detection via Finger Interactions with a Computer Keyboard During Natural Typing

    NASA Astrophysics Data System (ADS)

    Giancardo, L.; Sánchez-Ferro, A.; Butterworth, I.; Mendoza, C. S.; Hooker, J. M.

    2015-04-01

    Modern digital devices and appliances are capable of monitoring the timing of button presses, or finger interactions in general, with a sub-millisecond accuracy. However, the massive amount of high resolution temporal information that these devices could collect is currently being discarded. Multiple studies have shown that the act of pressing a button triggers well defined brain areas which are known to be affected by motor-compromised conditions. In this study, we demonstrate that the daily interaction with a computer keyboard can be employed as means to observe and potentially quantify psychomotor impairment. We induced a psychomotor impairment via a sleep inertia paradigm in 14 healthy subjects, which is detected by our classifier with an Area Under the ROC Curve (AUC) of 0.93/0.91. The detection relies on novel features derived from key-hold times acquired on standard computer keyboards during an uncontrolled typing task. These features correlate with the progression to psychomotor impairment (p < 0.001) regardless of the content and language of the text typed, and perform consistently with different keyboards. The ability to acquire longitudinal measurements of subtle motor changes from a digital device without altering its functionality may allow for early screening and follow-up of motor-compromised neurodegenerative conditions, psychological disorders or intoxication at a negligible cost in the general population.

  13. Psychomotor Impairment Detection via Finger Interactions with a Computer Keyboard During Natural Typing

    PubMed Central

    Giancardo, L.; Sánchez-Ferro, A.; Butterworth, I.; Mendoza, C. S.; Hooker, J. M.

    2015-01-01

    Modern digital devices and appliances are capable of monitoring the timing of button presses, or finger interactions in general, with a sub-millisecond accuracy. However, the massive amount of high resolution temporal information that these devices could collect is currently being discarded. Multiple studies have shown that the act of pressing a button triggers well defined brain areas which are known to be affected by motor-compromised conditions. In this study, we demonstrate that the daily interaction with a computer keyboard can be employed as means to observe and potentially quantify psychomotor impairment. We induced a psychomotor impairment via a sleep inertia paradigm in 14 healthy subjects, which is detected by our classifier with an Area Under the ROC Curve (AUC) of 0.93/0.91. The detection relies on novel features derived from key-hold times acquired on standard computer keyboards during an uncontrolled typing task. These features correlate with the progression to psychomotor impairment (p < 0.001) regardless of the content and language of the text typed, and perform consistently with different keyboards. The ability to acquire longitudinal measurements of subtle motor changes from a digital device without altering its functionality may allow for early screening and follow-up of motor-compromised neurodegenerative conditions, psychological disorders or intoxication at a negligible cost in the general population. PMID:25882641

  14. Distinct modes of interaction of the retinoic acid receptor alpha with natural and synthetic retinoids.

    PubMed

    Lefebvre, B; Mouchon, A; Formstecher, P; Lefebvre, P

    1998-04-30

    Retinoids regulate key cellular processes through their binding to their cognate nuclear receptors, RARs and RXRs. Synthetic ligands mimic most of their biological effects and alteration of their chemical structure confers selectivity for RAR isotypes alpha, beta or gamma. In this study, we have examined the contribution of a domain (L box) of hRARalpha located at the C-terminus of the ligand binding domain (LBD), between helices H11 and H12, to the ligand binding activity of this receptor. By site-directed mutagenesis, we demonstrate that, in the absence of the ligand-dependent activation domain 2 (AF2-AD), the receptor discriminates between classes of structurally distinct retinoids. This property was lost in the presence of the AF2-AD domain, evidencing major structural transitions in this part of the receptor. We propose that ligand binding occurs in two steps: first, the ligand interacts with the LBD in its opened, holo-receptor conformation in which the L box plays a crucial role in defining the ligand binding repertoire of hRARalpha; secondly, the LBD adopts its closed conformation in which the ligand interacts with the receptor mostly through its carboxylic moiety.

  15. Interaction between lysozyme and procyanidin: multilevel structural nature and effect of carbohydrates.

    PubMed

    Liang, Miao; Liu, Rui; Qi, Wei; Su, Rongxin; Yu, Yanjun; Wang, Libing; He, Zhimin

    2013-06-01

    The interaction of procyanidins with proteins has aroused extensive attention due to its important relationship with the bioavailability and astringent property of polyphenols. In the present work, we have investigated the interactions of lysozyme with procyanidin dimer (B3) using various biophysical approaches, which aims to provide insights into the mechanism of protein/polyphenol aggregation. Procyanidin B3 spontaneously binds lysozyme, inducing the multilevel structural changes in lysozyme and the formation of insoluble complexes. The relationship between lysozyme aggregation and the loss of enzymatic activity was monitored using dynamic light scattering and fluorescence quenching. The influences of two carbohydrates (gum arabic and sucrose) on lysozyme/B3 aggregation were also studied. Gum arabic effectively inhibited the formation of insoluble aggregates, but was unable to restore the fluorescence and activity of lysozyme. However, sucrose concomitantly decreased the aggregate size with the recovery of fluorescence and lysozyme activity. These results proposed two probable mechanisms by which these two carbohydrates inhibit protein/polyphenol aggregation.

  16. Rethinking the history of modern agriculture: British pig production, c.1910-65.

    PubMed

    Woods, Abigail

    2012-01-01

    This article uses a study of pig production in Britain, c.1910-65, to rethink the history of modern agriculture and its implications for human-animal relationships. Drawing on literature written by and for pig producers and experts, it challenges existing portrayals of a unidirectional, post-Second World War shift from traditional small-scale mixed farming to large, specialized, intensive systems. Rather, 'factory-style' pig production was already established in Britain by the 1930s, and its fortunes waxed and waned over time in relation to different kinds of outdoor production, which was still prominent in the mid-1960s. In revealing that the progressive proponents of both indoor and outdoor methods regarded them as modern and efficient, but defined and pursued these values in quite different ways, the article argues for a more historically situated understanding of agricultural modernity. Analysis reveals that regardless of their preferred production system, leading experts and producers were keen to develop what they considered to be natural methods that reflected the pig's natural needs and desires. They perceived pigs as active, sentient individuals, and believed that working in harmony with their natures was essential, even if this was, ultimately, for commercial ends. Such views contradict received accounts of modern farming as a utilitarian enterprise, concerned only with dominating and manipulating nature. They are used to argue that a romantic, moral view of the pig did not simply pre-date or emerge in opposition to modern agriculture, but, rather, was integral to it.

  17. Interactive effects of natural and anthropogenic factors on growth and physiology of southern red spruce

    SciTech Connect

    McLaughlin, S.B.; Andersen, C.P.; Hanson, P.J.; Norby, R.J.; Edwards, N.T.; Tardiff, R.R.

    1987-01-01

    Field and laboratory studies are underway to characterize physiologial changes associated with the decline of red spruce (Picea rubens Sarg.) at high elevations in the Great Smocky Mountains National Park. Two research plots have been established on Clingman's Dome at 1720 m and 1935 m elevations to document the magnitude of growth changes at sites experiencing varying degrees of growth decline and to explore the physiological basis of observed differences. The objective is to evaluate likely mechanisms of action and identify natural and anthropogenic factors influencing the observed growth patterns. Field measurements include historical and current radial growth of mature trees and saplings, and seasonal patterns of carbon assimilation, carbon allocation, and water relations of saplings. Laboratory experiments include dose response exposures with H/sub 2/O/sub 2/, toxicity screening studies with Al, Mn, and Ca, and characterization of the foliar uptake and metabolism of nitrogen oxides. 9 refs., 2 figs., 6 tabs.

  18. Modelling nitrogen and carbon interactions in composting of animal manure in naturally aerated piles.

    PubMed

    Oudart, D; Robin, P; Paillat, J M; Paul, E

    2015-12-01

    Composting animal manure with natural aeration is a low-cost and low-energy process that can improve nitrogen recycling in millions of farms world-wide. Modelling can decrease the cost of choosing the best options for solid manure management in order to decrease the risk of loss of fertilizer value and ammonia emission. Semi-empirical models are suitable, considering the scarce data available in farm situations. Eleven static piles of pig or poultry manure were monitored to identify the main processes governing nitrogen transformations and losses. A new model was implemented to represent these processes in a pile considered as homogeneous. The model is based on four modules: biodegradation, nitrogen transformations and volatilization, thermal exchanges, and free air space evolution. When necessary, the parameters were calibrated with the data set. The results showed that microbial growth could reduce ammonia volatilization. Greatest nitrogen conservation is achieved when microbial growth was limited by nitrogen availability.

  19. Thymic Low Affinity/Avidity Interaction Selects Natural Th1 Cells

    PubMed Central

    Kang, Byung Hyun; Park, Hyo Jin; Yum, Hye In; Park, Seung Pyo; Park, Jin Kyun; Kang, Eun Ha; Lee, Jae-Il; Lee, Eun Bong; Park, Chung-Gyu

    2015-01-01

    Identification of intrathymic eomesodermin+ (Eomes+) CD4 T cells creates a novel idea that there is more than one way for the generation of innate CD4 T cells. Promyelocytic leukemia zinc finger protein+ T cells and natural Th17 cells are known to be generated by sensing a high and persistent TCR strength, whereas this is not the case for Eomes+ CD4 T cells. These cells go through low-level signal during the entire maturation pathway, which subsequently leads to induction of high susceptibility to cytokine IL-4. This event seems to be a major determinant for the generation of this type of cell. These T cells are functionally equivalent to Th1 cells that are present in the periphery, and this event takes place both in transgenic and in wild-type mice. There is additional evidence that this type of Eomes+ innate CD4 T cell is also present in human cord blood. PMID:25972479

  20. Inhibition of growth and alteration of host cell interactions of Pasteurella multocida with natural byproducts.

    PubMed

    Salaheen, S; Almario, J A; Biswas, D

    2014-06-01

    Pasteurella multocida is a leading cause of fowl cholera in both free-range pasture and conventional/commercially raised poultry. Its infection is a serious threat to poultry health and overall flock viability. Organic poultry is comparatively more vulnerable to this pathogen. It is a significant cause of production loss and price increase of poultry products, specifically organic poultry products. Some plant products are well documented as sources of natural antimicrobials such as polyphenols found in different berry pomaces and citrus oil. Pomace, a byproduct (primarily of seeds and skins) of fruits used for juice and wine production, and citrus oil, the byproduct of citrus juice production, show promising antimicrobial activity against various pathogens. Here, we showed for the first time that blackberry and blueberry pomace extracts and citrus oil inhibited P. multocida growth. Minimum bactericidal concentrations were determined as 0.3 and 0.4 mg/mL gallic acid equivalent for blackberry and blueberry pomace extracts, respectively. Similarly, only 0.05% citrus oil (vol/vol) completely inhibited P. multocida growth. Under shaking conditions, the antimicrobial activity of both pomace extracts and citrus oil was more intensive. Even citrus oil vapor also significantly reduced the growth of P. multocida. In addition, cell surface hydrophobicity of P. multocida was increased by 2- to 3-fold and its adherence to chicken fibroblast (DF1) and bovine mammary gland (MacT) cells was reduced significantly in the presence of pomace extracts only. This study indicates that these natural products might be good alternatives to conventional antimicrobial agents, and hence, may be used as feed or water supplements to control fowl cholera and reduce production loss caused by P. multocida.

  1. Guest:host interactions of lidocaine and prilocaine with natural cyclodextrins: Spectral and molecular modeling studies

    NASA Astrophysics Data System (ADS)

    Rajendiran, N.; Mohandoss, T.; Saravanan, J.

    2014-11-01

    Inclusion complex formation of two local anesthetics drugs (lidocaine (LC) and prilocaine (PC)) with α- and β-cyclodextrins (CDs) in aqueous solution were studied by absorption, fluorescence, time-resolved fluorescence and molecular modeling methods. The formation of inclusion complexes was confirmed by 1H NMR, FTIR, differential scanning calorimetry, SEM, TEM and X-ray diffractometry. Both drugs formed 1:1 inclusion complex and exhibit biexponential decay in water whereas triexponential decay in the CD solution. Nanosized self-aggregated particles of drug: CD complexes were found by TEM. Both experimental and theoretical studies revealed that the phenyl ring with the amide group of the drug is encapsulated in the hydrophobic CD nanocavity. Investigations of energetic and thermodynamic properties confirmed the stability of the inclusion complexes. van der Waals interactions are mainly responsible for enthalpy driven complex formation of LC and PC with CDs.

  2. Occupant Interactions and Effectiveness of Natural Ventilation Strategies in Contemporary New Housing in Scotland, UK.

    PubMed

    Sharpe, Tim; Farren, Paul; Howieson, Stirling; Tuohy, Paul; McQuillan, Jonathan

    2015-07-21

    The need to reduce carbon emissions and fuel poverty has led to increased building envelope air tightness, intended to reduce uncontrolled ventilation heat losses. Ventilation strategies in dwellings still allow the use of trickle ventilators in window frames for background ventilation. The extent to which this results in "healthy" Indoor Air Quality (IAQ) in recently constructed dwellings was a concern of regulators in Scotland. This paper describes research to explore this. First a review of literature was conducted, then data on occupant interactions with ventilation provisions (windows, doors, trickle vents) gathered through an interview-based survey of 200 recently constructed dwellings, and measurements made on a sample of 40 of these. The main measured parameter discussed here is CO2 concentration. It was concluded after the literature review that 1000 ppm absolute was a reasonable threshold to use for "adequate" ventilation. The occupant survey found that there was very little occupant interaction with the trickle ventilators e.g., in bedrooms 63% were always closed, 28% always open, and in only 9% of cases occupants intervened to make occasional adjustments. In the measured dwellings average bedroom CO2 levels of 1520 ppm during occupied (night time) hours were observed. Where windows were open the average bedroom CO2 levels were 972 ppm. With windows closed, the combination of "trickle ventilators open plus doors open" gave an average of 1021 ppm. "Trickle ventilators open" gave an average of 1571 ppm. All other combinations gave averages of 1550 to 2000 ppm. Ventilation rates and air change rates were estimated from measured CO2 levels, for all dwellings calculated ventilation rate was less than 8 L/s/p, in 42% of cases calculated air change rate was less than 0.5 ach. It was concluded that trickle ventilation as installed and used is ineffective in meeting desired ventilation rates, evidenced by high CO2 levels reported across the sampled dwellings

  3. Interactions of an insecticide, herbicide, and natural stressors in amphibian community mesocosms

    USGS Publications Warehouse

    Boone, M.D.; James, S.M.

    2003-01-01

    Amphibians developing in wetlands embedded within or near agricultural lands may frequently encounter chemical mixtures. The objectives of our study were to determine the effects that post-application concentrations of an insecticide (carbaryl) and an herbicide (atrazine) have on body mass, development, and survival of two anuran species (southern leopard frog, Rana sphenocephala; American toad, Bufo americanus) and two caudate species (spotted salamander, Ambystoma maculatum; small-mouthed salamander, A. texanum) reared in outdoor cattle tank mesocosms. In one experiment, we manipulated tadpole density (low or high), carbaryl exposure (0, 3.5, 7.0 mg/L), and atrazine exposure (0 or 200 ??g/L) to test for effects on development, mass, and survival of larvae. In a second experiment, we manipulated pond hydroperiod (constant or drying), carbaryl exposure (0 or 5 mg/L), and atrazine exposure (0 or 200 ??g/L) to test for effects on mass, time, and survival to metamorphosis. Salamanders were virtually eliminated in carbaryl treatments, indicating that at realistic levels, this insecticide could cause population declines for salamanders in contaminated habitats. Carbaryl also had negative effects on toad survival. Exposure to atrazine had negative effects on body size, development, and time to metamorphosis in anuran species, which were associated with reduced chlorophyll levels. Both chemicals interacted significantly with density or hydroperiod, indicating that the environmental conditions could influence the impact of a contaminant. A significant atrazine-by-carbaryl interaction resulted in smaller and less developed spotted salamander larvae than in control ponds. Atrazine exposure, however, appeared to moderate negative effects of carbaryl for spotted salamanders. Our research suggests that important changes in the community's food web result from chemical exposure, which influence the susceptibility of amphibian species to contaminants.

  4. Interactivity in Health Care: Bodies, Values and Dynamics

    ERIC Educational Resources Information Center

    Pedersen, Sarah Bro

    2012-01-01

    This paper discusses recent paradigm changes in linguistics as well as other scientific disciplines in order to stress how such changes affect interactional approaches to health care. It argues that moving from a reductionist to a more holistic and trans-disciplinary approach to human interactivity entails a rethinking of both theory and…

  5. Towards a better understanding on agglomeration mechanisms and thermodynamic properties of TiO₂ nanoparticles interacting with natural organic matter.

    PubMed

    Loosli, Frédéric; Vitorazi, Letícia; Berret, Jean-François; Stoll, Serge

    2015-09-01

    Interaction between engineered nanoparticles and natural organic matter is investigated by measuring the exchanged heat during binding process with isothermal titration calorimetry. TiO2 anatase nanoparticles and alginate are used as engineered nanoparticles and natural organic matter to get an insight into the thermodynamic association properties and mechanisms of adsorption and agglomeration. Changes of enthalpy, entropy and total free energy, reaction stoichiometry and affinity binding constant are determined or calculated at a pH value where the TiO2 nanoparticles surface charge is positive and the alginate exhibits a negative structural charge. Our results indicate that strong TiO2-alginate interactions are essentially entropy driven and enthalpically favorable with exothermic binding reactions. The reaction stoichiometry and entropy gain are also found dependent on the mixing order. Finally correlation is established between the binding enthalpy, the reaction stoichiometry and the zeta potential values determined by electrophoretic mobility measurements. From these results two types of agglomeration mechanisms are proposed depending on the mixing order. Addition of alginate in TiO2 dispersions is found to form agglomerates due to polymer bridging whereas addition of TiO2 in alginate promotes a more individually coating of the nanoparticles.

  6. Ab initio no-core configuration interaction calculations of electromagnetic observables for p-shell nuclei using natural orbitals

    NASA Astrophysics Data System (ADS)

    Constantinou, Chrysovalantis; Caprio, Mark A.; Vary, James P.; Maris, Pieter

    2016-09-01

    The goal of ab initio nuclear theory is to provide quantitative predictions of nuclear observables, by solving the many-body problem starting from the internucleon interaction. The solution of the many-body problem involves large spaces with dimensions that grow fast with the number of nucleons and single-particle states included in the space. Convergence of nuclear observables in the employed space using an adequate set of single-particle orbitals is essential for making quantitative predictions. Long-range nuclear observables, such as the matrix elements of the E 2 operator, converge slowly when conventional oscillator single-particle orbitals are used for no-core configuration interaction (NCCI) calculations. Natural orbitals, obtained by diagonalizing the one-body density matrix from an initial NCCI calculation in the harmonic oscillator basis, provide accelerated convergence since they are adapted to the properties of the many-body wave function of the nucleus under study. We explore the convergence of electromagnetic observables of p-shell nuclei obtained using natural orbitals for NCCI calculations. Supported by the US DOE under Grants DE-FG02-95ER-40934, DESC0008485 (SciDAC/NUCLEI), and DE-FG02-87ER40371. Computational resources provided by NERSC (supported by US DOE Contract DE-AC02-05CH11231) and the Notre Dame Center for Research Computing.

  7. A flexible object-based software framework for modeling complex systems with interacting natural and societal processes.

    SciTech Connect

    Christiansen, J. H.

    2000-06-15

    The Dynamic Information Architecture System (DIAS) is a flexible, extensible, object-based framework for developing and maintaining complex multidisciplinary simulations. The DIAS infrastructure makes it feasible to build and manipulate complex simulation scenarios in which many thousands of objects can interact via dozens to hundreds of concurrent dynamic processes. The flexibility and extensibility of the DIAS software infrastructure stem mainly from (1) the abstraction of object behaviors, (2) the encapsulation and formalization of model functionality, and (3) the mutability of domain object contents. DIAS simulation objects are inherently capable of highly flexible and heterogeneous spatial realizations. Geospatial graphical representation of DIAS simulation objects is addressed via the GeoViewer, an object-based GIS toolkit application developed at ANL. DIAS simulation capabilities have been extended by inclusion of societal process models generated by the Framework for Addressing Cooperative Extended Transactions (FACET), another object-based framework developed at Argonne National Laboratory. By using FACET models to implement societal behaviors of individuals and organizations within larger DIAS-based natural systems simulations, it has become possible to conveniently address a broad range of issues involving interaction and feedback among natural and societal processes. Example DIAS application areas discussed in this paper include a dynamic virtual oceanic environment, detailed simulation of clinical, physiological, and logistical aspects of health care delivery, and studies of agricultural sustainability of urban centers under environmental stress in ancient Mesopotamia.

  8. Occupant Interactions and Effectiveness of Natural Ventilation Strategies in Contemporary New Housing in Scotland, UK

    PubMed Central

    Sharpe, Tim; Farren, Paul; Howieson, Stirling; Tuohy, Paul; McQuillan, Jonathan

    2015-01-01

    The need to reduce carbon emissions and fuel poverty has led to increased building envelope air tightness, intended to reduce uncontrolled ventilation heat losses. Ventilation strategies in dwellings still allow the use of trickle ventilators in window frames for background ventilation. The extent to which this results in “healthy” Indoor Air Quality (IAQ) in recently constructed dwellings was a concern of regulators in Scotland. This paper describes research to explore this. First a review of literature was conducted, then data on occupant interactions with ventilation provisions (windows, doors, trickle vents) gathered through an interview-based survey of 200 recently constructed dwellings, and measurements made on a sample of 40 of these. The main measured parameter discussed here is CO2 concentration. It was concluded after the literature review that 1000 ppm absolute was a reasonable threshold to use for “adequate” ventilation. The occupant survey found that there was very little occupant interaction with the trickle ventilators e.g., in bedrooms 63% were always closed, 28% always open, and in only 9% of cases occupants intervened to make occasional adjustments. In the measured dwellings average bedroom CO2 levels of 1520 ppm during occupied (night time) hours were observed. Where windows were open the average bedroom CO2 levels were 972 ppm. With windows closed, the combination of “trickle ventilators open plus doors open” gave an average of 1021 ppm. “Trickle ventilators open” gave an average of 1571 ppm. All other combinations gave averages of 1550 to 2000 ppm. Ventilation rates and air change rates were estimated from measured CO2 levels, for all dwellings calculated ventilation rate was less than 8 L/s/p, in 42% of cases calculated air change rate was less than 0.5 ach. It was concluded that trickle ventilation as installed and used is ineffective in meeting desired ventilation rates, evidenced by high CO2 levels reported across the

  9. Interaction of KRAS G-quadruplex with natural polyphenols: A spectroscopic analysis with molecular modeling.

    PubMed

    Pattanayak, Rudradip; Basak, Pijush; Sen, Srikanta; Bhattacharyya, Maitree

    2016-08-01

    Researchers are endeavoring to find out new therapeutics for curing cancer and G-quadruplex DNA has already been identified as a prospective one in this venture. Stabilizing G-quadruplex structures of telomere has emerged to be an important strategy in this context. Mutation in KRAS is mostly responsible for pancreatic, lung and colon cancer. In this present study we explored binding and conformational behaviour of G-quadruplex with different ligands by utilizing several biophysical techniques. Natural polyphenols like Curcumin and Ellagic acid were observed to bind with the G-quadruplex and enhance the melting temperature significantly indicating higher stability. UV-vis spectroscopy confirms formation of G quadruplex-ligand complex for both the compounds with specific binding affinity. Fluorimetric studies revealed that Ellagic acid had stronger binding affinity, 1.10×10(5)M(-1) compared to Curcumin, 1.6×10(4)M(-1) towards G-quadruplex. Interestingly, Curcumin provides greater stability by stacking on the top of the quadruplex structure with the help of the loops compared to Ellagic acid as is evident by docking studies. The keto form of curcumin showed stronger affinity than the enol form. We have developed a general model to estimate the influence of the ligands towards stabilizing the G-quadruplex subsequently characterizing the binding profile to enlighten prospective therapeutics.

  10. The combination of appetitive and aversive reinforcers and the nature of their interaction during auditory learning.

    PubMed

    Ilango, A; Wetzel, W; Scheich, H; Ohl, F W

    2010-03-31

    Learned changes in behavior can be elicited by either appetitive or aversive reinforcers. It is, however, not clear whether the two types of motivation, (approaching appetitive stimuli and avoiding aversive stimuli) drive learning in the same or different ways, nor is their interaction understood in situations where the two types are combined in a single experiment. To investigate this question we have developed a novel learning paradigm for Mongolian gerbils, which not only allows rewards and punishments to be presented in isolation or in combination with each other, but also can use these opposite reinforcers to drive the same learned behavior. Specifically, we studied learning of tone-conditioned hurdle crossing in a shuttle box driven by either an appetitive reinforcer (brain stimulation reward) or an aversive reinforcer (electrical footshock), or by a combination of both. Combination of the two reinforcers potentiated speed of acquisition, led to maximum possible performance, and delayed extinction as compared to either reinforcer alone. Additional experiments, using partial reinforcement protocols and experiments in which one of the reinforcers was omitted after the animals had been previously trained with the combination of both reinforcers, indicated that appetitive and aversive reinforcers operated together but acted in different ways: in this particular experimental context, punishment appeared to be more effective for initial acquisition and reward more effective to maintain a high level of conditioned responses (CRs). The results imply that learning mechanisms in problem solving were maximally effective when the initial punishment of mistakes was combined with the subsequent rewarding of correct performance.

  11. Group tele-immersion:enabling natural interactions between groups at distant sites.

    SciTech Connect

    Yang, Christine L. (Sandia National Laboratories, Livermore, CA); Stewart, Corbin (Sandia National Laboratories, Livermore, CA); Nashel, Andrew (University of North Carolina at Chapel Hill, Chapel Hill, NC)

    2005-08-01

    We present techniques and a system for synthesizing views for video teleconferencing between small groups. In place of replicating one-to-one systems for each pair of users, we create a single unified display of the remote group. Instead of performing dense 3D scene computation, we use more cameras and trade-off storage and hardware for computation. While it is expensive to directly capture a scene from all possible viewpoints, we have observed that the participants viewpoints usually remain at a constant height (eye level) during video teleconferencing. Therefore, we can restrict the possible viewpoint to be within a virtual plane without sacrificing much of the realism, and in cloning so we significantly reduce the number of required cameras. Based on this observation, we have developed a technique that uses light-field style rendering to guarantee the quality of the synthesized views, using a linear array of cameras with a life-sized, projected display. Our full-duplex prototype system between Sandia National Laboratories, California and the University of North Carolina at Chapel Hill has been able to synthesize photo-realistic views at interactive rates, and has been used to video conference during regular meetings between the sites.

  12. Natural resilience in Arctic charr Salvelinus alpinus: life history, spatial and dietary alterations along gradients of interspecific interactions.

    PubMed

    Hammar, J

    2014-07-01

    The Arctic charr Salvelinus alpinus species complex has been shown to be exceptionally vulnerable to rapid abiotic and biotic changes. Salvelinus alpinus, however, inhabit environmental extremes ranging from lakes and rivers in the High Arctic to deep multi-fish species lakes far outside the polar region. Long-term responses to post-glacial environmental variations and successively increased interspecific interactions reveal an essential degree of natural ecological resilience and phenotypic flexibility. Case studies in Scandinavia and Newfoundland illustrate the alternate trophic roles of S. alpinus, and its flexible niche use and life-history changes in order to regain or maintain body size in gradients of lakes with increasing fish species diversity. While allopatric in northern low-productive upland lakes, landlocked populations are commonly structured by cannibalism. In sympatry with other fish species, S. alpinus mostly serve as prey, with their decreasing growth and body size reflecting the successive diet shift from littoral macro-benthos to zooplankton and profundal microbenthos as interspecific competition for food and habitat intensifies. Interactions with natural and introduced superior zooplankton feeders and ultimate predators finally become detrimental. Consequently, the niche of S. alpinus is increasingly compressed in lakes along latitudinal and altitudinal gradients, although certain natural key conditions offer S. alpinus temporary asylum in the inescapable process towards local and regional extinction. The water temperature drop during winter allows S. alpinus to temporarily resume the richer littoral dietary and spatial niche use in low diversity lakes. In southern lowland and coastal lakes with more complex fish communities, access to key prey species such as profundal macro-crustaceans and smelt Osmerus spp. allow S. alpinus to regain its original niche space and characteristics as a large piscivore. In conclusion, S. alpinus along its

  13. Exploitation of natural genetic diversity to study plant-virus interactions: what can we learn from Arabidopsis thaliana?

    PubMed

    Ouibrahim, Laurence; Caranta, Carole

    2013-10-01

    The development and use of cultivars that are genetically resistant to viruses is an efficient strategy to tackle the problems of virus diseases. Over the past two decades, the model plant Arabidopsis thaliana has been documented as a host for a broad range of viral species, providing access to a large panel of resources and tools for the study of viral infection processes and resistance mechanisms. Exploration of its natural genetic diversity has revealed a wide range of genes conferring virus resistance. The molecular characterization of some of these genes has unveiled resistance mechanisms distinct from those described in crops. In these respects, Arabidopsis represents a rich and largely untapped source of new genes and mechanisms involved in virus resistance. Here, we review the current status of our knowledge concerning natural virus resistance in Arabidopsis. We also address the impact of environmental conditions on Arabidopsis-virus interactions and resistance mechanisms, and discuss the potential of applying the knowledge gained from the study of Arabidopsis natural diversity for crop improvement.

  14. Presence redefined: The reciprocal nature of engagement between elder-clowns and persons with dementia.

    PubMed

    Kontos, Pia; Miller, Karen-Lee; Mitchell, Gail Joyce; Stirling-Twist, Jan

    2015-04-23

    Elder-clowns are a recent innovation in arts-based approaches to person-centred dementia care. They use improvisation, humour, and empathy, as well as song, dance, and music. We examined elder-clown practice and techniques through a 12-week programme with 23 long-term care residents with moderate to severe dementia in Ontario, Canada. Analysis was based on qualitative interviews and ethnographic observations of video-recorded clown-resident interactions and practice reflections. Findings highlight the reciprocal nature of clown-resident engagement and the capacity of residents to initiate as well as respond to verbal and embodied engagement. Termed relational presence, this was achieved and experienced through affective relationality, reciprocal playfulness, and coconstructed imagination. These results highlight the often overlooked capacity of individuals living with dementia to be deliberately funny, playful, and imaginative. Relational presence offers an important perspective with which to rethink care relationships between individuals living with dementia and long-term care staff.

  15. [Visual and olfactory factors interaction in resource-location by the blowfly, Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae), in natural conditions].

    PubMed

    Gomes, Leonardo; Gomes, Guilherme; Casarin, Fabiana E; da Silva, Iracema M; Sanches, Marcos R; Von Zuben, Claudio J; Fowler, Harold G

    2007-01-01

    The interaction between olfactory and visual cues in the landing responses of Chrysomya megacephala (Fabricius) was analyzed in a natural environment (grass) using three plain cardboard circles with the colors white, black and other being the own grass (control) with 30 cm in diameter. The circles were divided in four quadrants and five sectors using as bait 80 mg of carcass of fish and minced flesh put in the center. To check the interaction between visual and olfactory factors, we analyzed the relation among the direction of wind and the sectors, the quadrants and the color of circle where C. megacephala adults landed. In the presence of the black and white circles, flies landed closer to the central release point of the bait when the wind was present compared with the other control circle. The results show that while odor cues may enhance the induction of landing by C. megacephala, visual cues are important when selecting a final landing site. Improved understanding of this interaction may allow the development of more effective traps or targets, enhancing the control efficiency of these control devices.

  16. The interaction of human natural killer cells with either unpolarized or polarized macrophages results in different functional outcomes.

    PubMed

    Bellora, Francesca; Castriconi, Roberta; Dondero, Alessandra; Reggiardo, Giorgio; Moretta, Lorenzo; Mantovani, Alberto; Moretta, Alessandro; Bottino, Cristina

    2010-12-14

    The cross-talk among cells of the innate immunity can greatly affect both innate and adaptive responses. Here we analyzed the molecular interactions between human natural killer (NK) cells and autologous macrophages. Activated NK cells killed M0 and M2, whereas M1 macrophages were more resistant to lysis because of their higher expression of HLA class I molecules. Following exposure to LPS or bacillus Calmette-Guérin, M0 and M2, but not polarized (endotoxin tolerant) M1 macrophages, induced strong activation of resting NK cells. The expression of CD69 and CD25 activation markers and the acquisition of cytotoxicity against tumor cells and immature dendritic cells required soluble factors being mostly contact independent. On the contrary, IFN-γ production was contact dependent and required the interaction of DNAM-1 and 2B4 (on NK) with their ligands on macrophages as well as IL-18. IL-18 was involved also in the acquisition of CCR7 by NK cells. Interestingly, M0 and M2 cells expressed a membrane-bound form of IL-18, which was released in small amounts after LPS treatment. Our data indicate that, upon interaction with M0 macrophages exposed to microbial products, NK cells may amplify classical type 1 immune responses. In addition, M1-polarizing stimuli can rescue M2 macrophages from their immunomodulatory state and shape their functional behavior toward NK stimulatory capability.

  17. Configuration interaction singles natural orbitals: An orbital basis for an efficient and size intensive multireference description of electronic excited states

    SciTech Connect

    Shu, Yinan; Levine, Benjamin G.; Hohenstein, Edward G.

    2015-01-14

    Multireference quantum chemical methods, such as the complete active space self-consistent field (CASSCF) method, have long been the state of the art for computing regions of potential energy surfaces (PESs) where complex, multiconfigurational wavefunctions are required, such as near conical intersections. Herein, we present a computationally efficient alternative to the widely used CASSCF method based on a complete active space configuration interaction (CASCI) expansion built from the state-averaged natural orbitals of configuration interaction singles calculations (CISNOs). This CISNO-CASCI approach is shown to predict vertical excitation energies of molecules with closed-shell ground states similar to those predicted by state averaged (SA)-CASSCF in many cases and to provide an excellent reference for a perturbative treatment of dynamic electron correlation. Absolute energies computed at the CISNO-CASCI level are found to be variationally superior, on average, to other CASCI methods. Unlike SA-CASSCF, CISNO-CASCI provides vertical excitation energies which are both size intensive and size consistent, thus suggesting that CISNO-CASCI would be preferable to SA-CASSCF for the study of systems with multiple excitable centers. The fact that SA-CASSCF and some other CASCI methods do not provide a size intensive/consistent description of excited states is attributed to changes in the orbitals that occur upon introduction of non-interacting subsystems. Finally, CISNO-CASCI is found to provide a suitable description of the PES surrounding a biradicaloid conical intersection in ethylene.

  18. A Natural Mutation in Helix 5 of the Ligand Binding Domain of Glucocorticoid Receptor Enhances Receptor-Ligand Interaction

    PubMed Central

    Reyer, Henry; Ponsuksili, Siriluck; Kanitz, Ellen; Pöhland, Ralf; Wimmers, Klaus; Murani, Eduard

    2016-01-01

    The glucocorticoid receptor (GR) is a central player in the neuroendocrine stress response; it mediates feedback regulation of the hypothalamus-pituitary-adrenal (HPA) axis and physiological actions of glucocorticoids in the periphery. Despite intensive investigations of GR in the context of receptor-ligand interaction, only recently the first naturally occurring gain-of-function substitution, Ala610Val, of the ligand binding domain was identified in mammals. We showed that this mutation underlies a major quantitative trait locus for HPA axis activity in pigs, reducing cortisol production by about 40–50 percent. To unravel the molecular mechanisms behind this gain of function, receptor-ligand interactions were evaluated in silico, in vitro and in vivo. In accordance with previously observed phenotypic effects, the mutant Val610 GR showed significantly increased activation in response to glucocorticoid and non-glucocorticoid steroids, and, as revealed by GR-binding studies in vitro and in pituitary glands, enhanced ligand binding. Concordantly, the protein structure prediction depicted reduced binding distances between the receptor and ligand, and altered interactions in the ligand binding pocket. Consequently, the Ala610Val substitution opens up new structural information for the design of potent GR ligands and to examine effects of the enhanced GR responsiveness to glucocorticoids on the entire organism. PMID:27736993

  19. On the nature of the B...N interaction and the conformational flexibility of arylboronic azaesters.

    PubMed

    Durka, Krzysztof; Kamiński, Radosław; Luliński, Sergiusz; Serwatowski, Janusz; Woźniak, Krzysztof

    2010-10-28

    It is shown that the structural and physicochemical properties of arylboronic azaesters result from the properties of the key B-N bond. This bond is different in arylboronic azaesters from typical single/double/triple B-N bonds present in other boron-nitrogen compounds. By studying a model example, 6-tert-butyl-2-(3',5'-difluorophenyl)-(N-B)-1,3,6,2-dioxazaborocane, it is proved that the molecule adopts the closed form in the solid state with the BN bond length equal to 1.7646(3) Å. This represents the longest B-N bond length for an arylboronic ester reported in literature. According to the results of experimental charge density studies and QTAIM analysis, the BN bond/contact shows good separation of the respective atomic basins and significant flexibility. The source function and NBO analyses indicate an evident involvement of the oxygen atoms in the creation of the B-N bonding. According to our DFT calculations the isolated model molecule exists in the open conformer. The constrained energy scans reveal an E(d(B-N)) potential energy surface which depends strongly on the nature of the substituents at the nitrogen and aromatic carbon atoms. It appears that an appropriate substitution can produce either conformer. A dipole moment analysis provides a good insight into the reactivity properties of the compound in solution. The opening of the azaester cage is associated with a breaking of the B-N bond, thus decreasing the magnitude of the dipole moment. The existence of the open conformer is confirmed by multi-temperature NMR studies. When decreasing the temperature of the measurements the (1)H and (11)B NMR spectra show features corresponding to the open form of the model arylboronic azaester.

  20. Call intercalation in dyadic interactions in natural choruses of Johnstone's whistling frog Eleutherodactylus johnstonei (Anura: Eleutherodactylidae).

    PubMed

    Tárano, Zaida; Carballo, Luisana

    2016-05-01

    Communal signaling increases the likelihood of acoustic interference and impairs mate choice; consequently, mechanisms of interference avoidance are expected. Adjustment of the timing of the calls between signalers, specifically call alternation, is probably the most efficient strategy. For this reason, in the present study we analyzed call timing in dyads of males of E. johnstonei in six natural assemblages. We addressed whether males entrain their calls with those of other males at the assemblage and if they show selective attention in relation to perceived amplitude of the other males' calls, inter-male distance, or intrinsic call features (call duration, period or dominant frequency). We expected males to selectively attend to closer or louder males and/or to those of higher or similar attractiveness for females than themselves, because those would be their strongest competitors. We found that most males intercalated their calls with those of at least one male. In assemblages of 3 individuals, males seemed to attend to a fixed number of males regardless of their characteristics. In assemblages of more than 3 individuals, the perceived amplitude of the call of the neighboring male was higher, and the call periods of the males were more similar in alternating dyads than in the non-alternating ones. At the proximate level, selective attention based on perceived amplitude may relate to behavioral hearing thresholds. Selective attention based on the similarity of call periods may relate to the properties of the call oscillators controlling calling rhythms. At the ultimate level, selective attention may be related to the likelihood of acoustic competition for females.

  1. Microbial interactions with naturally occurring hydrophobic sediments: Influence on sediment and associated contaminant mobility.

    PubMed

    Droppo, I G; Krishnappan, B G; Lawrence, J R

    2016-04-01

    The erosion, transport and fate of sediments and associated contaminants are known to be influenced by both particle characteristics and the flow dynamics imparted onto the sediment. The influential role of bitumen containing hydrophobic sediments and the microbial community on sediment dynamics are however less understood. This study links an experimental evaluation of sediment erosion with measured sediment-associated contaminant concentrations and microbial community analysis to provide an estimate of the potential for sediment to control the erosion, transport and fate of contaminants. Specifically the paper addresses the unique behaviour of hydrophobic sediments and the role that the microbial community associated with hydrophobic sediment may play in the transport of contaminated sediment. Results demonstrate that the hydrophobic cohesive sediment demonstrates unique transport and particle characteristics (poor settling and small floc size). Biofilms were observed to increase with consolidation/biostabilization times and generated a unique microbial consortium relative to the eroded flocs. Natural oil associated with the flocs appeared to be preferentially associated with microbial derived extracellular polymeric substances. While PAHs and naphthenic acid increased with increasing shear (indicative of increasing loads), they tended to decrease with consolidation/biostabilization (CB) time at similar shears suggesting a chemical and/or biological degradation. PAH and napthenic acid degrading microbes decreased with time as well, which may suggest that there was a reduced pool of PAHs and naphthenic acids available resulting in their die off. This study emphasizes the importance that any management strategies and operational assessments for the protection of human and aquatic health incorporate the sediment (suspended and bed sediment) and biological (biofilm) compartments and the energy dynamics within the system in order to better predict contaminant

  2. Interactive effects of senescence and natural disturbance on the annual survival probabilities of snail kites

    USGS Publications Warehouse

    Reichert, Brian E.; Martin, J.; Kendall, William L.; Cattau, Christopher E.; Kitchens, Wiley M.

    2010-01-01

    Individuals in wild populations face risks associated with both intrinsic (i.e. aging) and external (i.e. environmental) sources of mortality. Condition-dependent mortality occurs when there is an interaction between such factors; however, few studies have clearly demonstrated condition-dependent mortality and some have even argued that condition-dependent mortality does not occur in wild avian populations. Using large sample sizes (2084 individuals, 3746 re-sights) of individual-based longitudinal data collected over a 33 year period (1976-2008) on multiple cohorts, we used a capture-mark-recapture framework to model age-dependent survival in the snail kite Rostrhamus sociabilis plumbeus population in Florida. Adding to the growing amount of evidence for actuarial senescence in wild populations, we found evidence of senescent declines in survival probabilities in adult kites. We also tested the hypothesis that older kites experienced condition-dependent mortality during a range-wide drought event (2000-2002). The results provide convincing evidence that the annual survival probability of senescent kites was disproportionately affected by the drought relative to the survival probability of prime-aged adults. To our knowledge, this is the first evidence of condition-dependent mortality to be demonstrated in a wild avian population, a finding which challenges recent conclusions drawn in the literature. Our study suggests that senescence and condition-dependent mortality can affect the demography of wild avian populations. Accounting for these sources of variation may be particularly important to appropriately compute estimates of population growth rate, and probabilities of quasi-extinctions.

  3. The nature of interactions between tissue-type plasminogen activator and platelets

    SciTech Connect

    Torr, S.R.; Winters, K.J.; Santoro, S.A.; Sobel, B.E. )

    1990-07-15

    To elucidate interactions responsible for inhibition of aggregation of platelets in platelet-rich plasma (PRP) harvested from whole blood preincubated with t-PA, experiments were performed with PRP and washed platelets under diverse conditions of preincubation. Both ADP and collagen induced aggregation were inhibited in PRP unless aprotinin had been added to the preincubated whole blood concomitantly with t-PA. However, in washed platelets prepared after the same exposure aggregation was intact. When washed platelets were supplemented with fibrinogen degradation products (FDPs) in concentrations simulating those in whole blood preincubated with t-PA, aggregation induced with either ADP or collagen was inhibited. Thus, the inhibition in PRP depended on generation of FDPs by activated plasminogen. The functional integrity of surface glycoprotein (GP) IIb/IIIa receptors in washed platelets was documented by autoradiography after SDS-PAGE of surface labeled GPs and by fibrinogen binding despite preincubation of the whole blood or washed platelets themselves with t-PA and plasminogen as long as exogenous calcium (greater than or equal to 0.1 microM) was present. In contrast, when calcium was absent, the platelet GP IIb/IIIa receptor was rendered susceptible to degradation by plasmin, and aggregation was inhibited by preincubation at 37 degrees C even if aprotinin was present when aggregation was being assayed. These observations reconcile disparate results in the literature from studies in vivo and in vitro by demonstrating that inhibition of aggregation of platelets in PRP and in whole blood reflects indirect effects of plasminogen activation rather than direct effects of t-PA or plasmin on the platelets themselves.

  4. Nature of the spin-glass phase in models with long-range interactions

    NASA Astrophysics Data System (ADS)

    Wittmann, Matthew C.

    Despite decades of effort, our understanding of low-temperature phase of spin glass models with short-range interactions remains incomplete. Replica symmetry breaking (RSB) theory, based on the solution of the Sherrington-Kirkpatrick mean-field model, predicts many pure states; meanwhile, competing theories of short-range systems, such as the droplet picture, predict a single pair of pure states related by time-reversal symmetry, analogously to the ferromagnet. Since RSB certainly holds for the mean-field (infinite-range) model, it is interesting to study short-range models in high dimensions to observe whether RSB also holds here; however, computer simulations of short-range models in high dimensions are difficult because the number of spins to equilibrate grows so rapidly with the linear size of the system. A relatively recent idea which has been fruitful is to instead study one-dimensional models with long-range (power-law) interactions, which are argued to have the same critical behavior as corresponding short-range models in high dimensions, but for which simulations for a range of sizes (crucial for finite-size scaling analysis) are feasible. For these one-dimensional long-range (1DLR) models, we fill in a previously unexplored region of parameter space where the interactions become sufficiently long-range that they must be rescaled with the system size to maintain the thermodynamic limit. We find strong evidence that detailed behavior of the 1DLR models everywhere in this "nonextensive regime" is identical to that of the Sherrington-Kirkpatrick model, lending support to a recent conjecture. In an attempt to distinguish the RSB and droplet pictures, we study recently-proposed observables based on the statistics of individual disorder samples, rather than simply averaging over the disorder as is most frequently done in previous studies. We compare Monte Carlo results for 1DLR models which are proxies for short-range models in 3, 4, and 10 dimensions with

  5. Interaction of rising frazil with suspended particles: tank experiments with applications to nature

    USGS Publications Warehouse

    Reimnitz, E.; Clayton, J.R.; Kempema, E.W.; Payne, J.R.; Weber, W.S.

    1993-01-01

    Widespread occurrence of sediment-laden (turbid) sea ice and high concentrations of diatoms and foraminifers in ice have recently been reported from both polar regions. Many possible mechanisms of particle entrainment into ice have been postulated, among which scavenging by rising frazil ice and nucleation or adhesion of ice onto suspended particles appear to be the most likely ones. No reliable experimental data on the mechanisms, however, are available. Because of the importance of turbid ice for sediment transport, tanks for laboratory-scale experiments were constructed, in which frazil crystals produced at the base were monitored rising through water column laden with various types of particulate matter, including plankton. Observations made in salt water are reported here. Over a distance of 1.5 m, frazil < 1 mm in diameter grew to crystals or flocs several cm in diameter, rising at average velocities of 2 to 3 cm/s. Rise velocities were a function of frazil size, but varied greatly due to interactions of ice particles of different size and velocity and the resulting turbulence. Sand-size particles could be either trapped permanently by rising frazil, or were temporarily supported and again released. With live plankton, a several-fold enrichment of ice occurred, suggesting that their irregular shapes or appendages were caught by ice flocs. Diatom- and foram tests were also relatively effectively trapped. The concentration of silt- and clay-size terrigenous detritus in frazil tended to increase relative to the water. We found no preferential sorting by ice in this size range. Various kinds of evidence showed that ice does not nucleate onto foreign particles, and has no adhesive properties. Foreign material resided in the interstices of crystal aggregates, and particles denser than water could be released by agitation, suggesting that scavenging is a mechanical process. With rising frazil, the settling of particulate matter therefore is either retarded or

  6. Rethinking soil erosion, phosphorus and colloid transfers from intensive grasslands

    NASA Astrophysics Data System (ADS)

    Brazier, R. E.; Bilotta, G.

    2006-12-01

    undrained plots. Results are presented as time series at each plot as well as event, monthly, seasonal and annual budgets. Results indicate that significant, event-based yields of both sediments (1.18 kg ha-1 from drained plots and 3.09 kg ha-1 from undrained plots) and nutrients (3.9 g ha-1 of TP from drained plots and 9.86 g ha-1 from undrained plots) are forthcoming, as the artificial drainage influences both the hydrograph response and form to natural rainfall events. In addition, significant yields of fine particles (<0.45ìm), of both organic and inorganic origin (colloids) are observed, from both drained and undrained plots, associated with high levels of particulate phosphorus. Such results suggest that though grasslands may not suffer from `classical' erosion processes, such as rilling and gullying, they can still contribute significant levels of fine sediments and nutrients, whether they are drained or not, which in turn will make a detrimental impact on the quality of adjacent surface waters. Bilotta, G. S., and Brazier, R.E. (in press). Rethinking soil erosion and sediment and colloid transfers from intensive grasslands. Hydrological Processes. Heathwaite, A.L. and Dils, R.M. (2000) Characterising phosphorus loss in surface and subsurface hydrological pathways. The Science Of The Total Environment, 251/252: 523-538. Sharpley, A.N., Foy, R.H. and Withers, P.J.A. (2000) Practical and innovative measures for the control of agricultural phosphorus losses to water. An Overview. Journal of Environmental Quality, 29: 1-9.

  7. Skin Cancer Risk Is Modified by KIR/HLA Interactions That Influence the Activation of Natural Killer Immune Cells.

    PubMed

    Vineretsky, Karin A; Karagas, Margaret R; Christensen, Brock C; Kuriger-Laber, Jacquelyn K; Perry, Ann E; Storm, Craig A; Nelson, Heather H

    2016-01-15

    Natural killer (NK)-cell phenotype is partially mediated through binding of killer-cell immunoglobulin-like receptors (KIR) with HLA class I ligands. The KIR gene family is highly polymorphic and not well captured by standard genome-wide association study approaches. Here, we tested the hypothesis that variations in KIR gene content combined with HLA class I ligand status is associated with keratinocyte skin cancers using a population-based study of basal cell carcinoma (BCC) and squamous cell carcinomas (SCC). We conducted an interaction analysis of KIR gene content variation and HLA-B (Bw4 vs. Bw6) and HLA-C (C1 vs. C2). KIR centromeric B haplotype was associated with significant risk of multiple BCC tumors (OR, 2.39; 95% confidence interval, 1.10-5.21), and there was a significant interaction between HLA-C and the activating gene KIR2DS3 for BCC (Pinteraction = 0.005). Furthermore, there was significant interaction between HLA-B and telomeric KIR B haplotype (containing the activating genes KIR3DS1 and KIR2DS1) as well as HLA-B and the activating KIR gene KIR2DS5 (Pinteraction 0.001 and 0.012, respectively). Similar but greatly attenuated associations were observed for SCC. Moreover, previous in vitro models demonstrated that p53 is required for upregulation of NK ligands, and accordingly, we observed there was a strong association between the KIR B haplotype and p53 alteration in BCC tumors, with a higher likelihood that KIR B carriers harbor abnormal p53 (P < 0.004). Taken together, our data suggest that functional interactions between KIR and HLA modify risks of BCC and SCC and that KIR encoded by the B genes provides selective pressure for altered p53 in BCC tumors.

  8. Nonlinear interaction of long dispersive Kelvin waves in deep natural basins

    NASA Astrophysics Data System (ADS)

    Budnev, Nikolay M.; Lovtsov, Sergey V.; Portyanskaya, Inna A.; Rastegin, Alexey E.; Rubtsov, Valeriy Yu.

    2010-05-01

    solitons in two-liquid systems are certainly assigned by deformation convex into thicker layer. This is another reason for studies of nonlinear Kelvin waves in strongly stratified fluids. At the same time, the developed method may be useful beyond and outside the described processes in natural reservoirs. In our analysis, we have used the variant of technique known as derivative expansion method. All the dependent and independent variables are reduced to dimensionless form. The principal moment of our approach consists in consideration of boundary with vertical wall with model dispersion term introduced in dynamic equation immediately. This simplifies analysis in comparison with the original equations with generally unknown coast slope on shelf. Even if this slope is approximated by analytical expression then mathematical transformations remain enough difficult. On the other hand, the final dimensionless equations should contain only contribution of first order from dispersion caused by boundary effects. So, as initial step we merely introduce a dispersive term of proper form that is provided by similarity reasons. In zero order with respect to small parameter, the standard relations of linear theory of Kelvin waves are obtained. In order to build those expansions those are uniformly valid for all times, we reduced a certain terms to zero. So the system of nonlinear KdV-like equations is arisen as condition that all the secular terms have been removed in the first order. We also discuss possible approaches to solution of obtained equations in regimes of one- and two excited vertical modes of oscillations.

  9. In Search of Ecopedagogy: Emplacing Nature in the Light of Proust and Thoreau

    ERIC Educational Resources Information Center

    Hung, Ruyu

    2014-01-01

    In this article I intend to explore one possible way of using "place" to rethink "nature," the relationship between humans and nature, and the implications for education. The elucidation and discussion of the sense of place will reveal that there are profound and superficial or, placeful and placeless, senses of place. This…

  10. Why Machiavellianism Matters in Childhood: The Relationship Between Children's Machiavellian Traits and Their Peer Interactions in a Natural Setting

    PubMed Central

    Abell, Loren; Qualter, Pamela; Brewer, Gayle; Barlow, Alexandra; Stylianou, Maria; Henzi, Peter; Barrett, Louise

    2015-01-01

    The current study investigated the association between Machiavellianism and children’s peer interactions in the playground using observational methods. Primary school children (N = 34; 17 female), aged 9 to 11 years, completed the Kiddie Mach scale and were observed in natural play during 39 recesses (average observed time = 11.70 hours) over a full school year. Correlations for boys revealed that Machiavellianism was related to more time engaging in direct and indirect aggression, being accepted into other peer groups, and accepting peers into their own social group. Correlations revealed that for girls, Machiavellianism was associated with lower levels of indirect aggression, less time being accepted into other groups and less time accepting and rejecting other children into their own group. This preliminary pilot study indicates that Machiavellianism is associated with children’s observed social behaviour and aims to promote future observational research in this area. PMID:27247672

  11. Natural orbitals from single and double excitation configuration interaction wave functions: their use in second-order configuration interaction and wave functions incorporating limited triple and quadruple excitations

    NASA Astrophysics Data System (ADS)

    Grev, Roger S.; Schaefer, Henry F., III

    1992-05-01

    As an alternative to orbitals obtained from a molecular complete-active-space self-consistent-field (CASSCF) wave function, we have investigated the use of natural orbitals (NOs) obtained from configuration interaction (CI) wave functions including all single and double excitations (CISD) for use in multireference CI (MRCI) studies. The specific MRCI methods investigated are (1) second-order CI (SOCI), which includes all single and double excitations with respect to a full CI in the valence space and (2) a wave function that includes all single and double excitations out of a valence space CISD reference function. The latter wave function can also be described as a single-double-triple-quadruple excitation CI in which only two electrons are allowed to simultaneously reside outside of the valence space, ``which we call CISD[TQ].'' Comparison is made with CASSCF-SOCI and full CI results for NH2 (2B1), CH3 (2A`2), and SiH2 (1B1) at equilibrium bond distances (Re) 1.5 and 2.0Re, and with full CI results for the dissociation energy of N2. The dissociation energies of N2 and C2 are also obtained using large atomic natural orbital basis sets and the results compared to CASSCF-SOCI and internally contracted MRCI results. In all, the MRCI results with CISD NOs are very similar to the CASSCF-MRCI results, and at geometries where the reference wave function is dominant, the relatively compact CISD[TQ] method yields results that are very close to SOCI. In addition to their ease of generation, the CISD NOs offer the added advantage of allowing for truncation of the CI configuration list on an orbital basis by simply deleting high-lying virtual orbitals. The errors introduced by this truncation are almost quantitatively obtained at the CISD level of theory.

  12. Women and Nature: Using Memory-Work to Rethink Our Relationship to the Natural World

    ERIC Educational Resources Information Center

    Kaufman, Judith S.; Ewing, Margaret S.; Hyle, Adrienne E.; Montgomery, Diane; Self, Patricia A.

    2006-01-01

    Memory-work is a feminist research methodology that is used by research collectives to study socialization within the dominant values that make up a particular culture. The power of memory-work lies with its potential to interrupt hegemonic ways of seeing and knowing the world. Consequently, it can open up possibilities for individual and social…

  13. Quercetin, a Natural Flavonoid Interacts with DNA, Arrests Cell Cycle and Causes Tumor Regression by Activating Mitochondrial Pathway of Apoptosis

    PubMed Central

    Srivastava, Shikha; Somasagara, Ranganatha R.; Hegde, Mahesh; Nishana, Mayilaadumveettil; Tadi, Satish Kumar; Srivastava, Mrinal; Choudhary, Bibha; Raghavan, Sathees C.

    2016-01-01

    Naturally occurring compounds are considered as attractive candidates for cancer treatment and prevention. Quercetin and ellagic acid are naturally occurring flavonoids abundantly seen in several fruits and vegetables. In the present study, we evaluate and compare antitumor efficacies of quercetin and ellagic acid in animal models and cancer cell lines in a comprehensive manner. We found that quercetin induced cytotoxicity in leukemic cells in a dose-dependent manner, while ellagic acid showed only limited toxicity. Besides leukemic cells, quercetin also induced cytotoxicity in breast cancer cells, however, its effect on normal cells was limited or none. Further, quercetin caused S phase arrest during cell cycle progression in tested cancer cells. Quercetin induced tumor regression in mice at a concentration 3-fold lower than ellagic acid. Importantly, administration of quercetin lead to ~5 fold increase in the life span in tumor bearing mice compared to that of untreated controls. Further, we found that quercetin interacts with DNA directly, and could be one of the mechanisms for inducing apoptosis in both, cancer cell lines and tumor tissues by activating the intrinsic pathway. Thus, our data suggests that quercetin can be further explored for its potential to be used in cancer therapeutics and combination therapy. PMID:27068577

  14. Amyloidogenic Propensity of a Natural Variant of Human Apolipoprotein A-I: Stability and Interaction with Ligands

    PubMed Central

    Rosú, Silvana A.; Rimoldi, Omar J.; Prieto, Eduardo D.; Curto, Lucrecia M.; Delfino, José M.

    2015-01-01

    A number of naturally occurring mutations of human apolipoprotein A-I (apoA-I) have been associated with hereditary amyloidoses. The molecular mechanisms involved in amyloid-associated pathology remain largely unknown. Here we examined the effects of the Arg173Pro point mutation in apoA-I on the structure, stability, and aggregation propensity, as well as on the ability to bind to putative ligands. Our results indicate that the mutation induces a drastic loss of stability, and a lower efficiency to bind to phospholipid vesicles at physiological pH, which could determine the observed higher tendency to aggregate as pro-amyloidogenic complexes. Incubation under acidic conditions does not seem to induce significant desestabilization or aggregation tendency, neither does it contribute to the binding of the mutant to sodium dodecyl sulfate. While the binding to this detergent is higher for the mutant as compared to wt apoA-I, the interaction of the Arg173Pro variant with heparin depends on pH, being lower at pH 5.0 and higher than wt under physiological pH conditions. We suggest that binding to ligands as heparin or other glycosaminoglycans could be key events tuning the fine details of the interaction of apoA-I variants with the micro-environment, and probably eliciting the toxicity of these variants in hereditary amyloidoses. PMID:25950566

  15. The nature of inter- and intramolecular interactions in F2OXe(…)HX (X= F, Cl, Br, I) complexes.

    PubMed

    Makarewicz, Emilia; Lundell, Jan; Gordon, Agnieszka J; Berski, Slawomir

    2016-06-01

    Electronic structure of the XeOF2 molecule and its two complexes with HX (X= F, Cl, Br, I) molecules have been studied in the gas phase using quantum chemical topology methods: topological analysis of electron localization function (ELF), electron density, ρ(r), reduced gradient of electron density |RDG(r)| in real space, and symmetry adapted perturbation theory (SAPT) in the Hilbert space. The wave function has been approximated by the MP2 and DFT methods, using APF-D, B3LYP, M062X, and B2PLYP functionals, with the dispersion correction as proposed by Grimme (GD3). For the Xe-F and Xe=O bonds in the isolated XeOF2 molecule, the bonding ELF-localization basins have not been observed. According to the ELF results, these interactions are not of covalent nature with shared electron density. There are two stable F2OXe(…)HF complexes. The first one is stabilized by the F-H(…)F and Xe(…)F interactions (type I) and the second by the F-H(…)O hydrogen bond (type II). The SAPT analysis confirms the electrostatic term, Eelst ((1)) and the induction energy, Eind ((2)) to be the major contributors to stabilizing both types of complexes.

  16. Natural products mediating ecological interactions in Antarctic benthic communities: a mini-review of the known molecules.

    PubMed

    Núñez-Pons, L; Avila, C

    2015-07-01

    Out of the many bioactive compounds described from the oceans, only a small fraction have been studied for their ecological significance. Similarly, most chemically mediated interactions are not well understood, because the molecules involved remain unrevealed. In Antarctica, this gap in knowledge is even more acute in comparison to tropical or temperate regions, even though polar organisms are also prolific producers of chemical defenses, and pharmacologically relevant products are being reported from the Southern Ocean. The extreme and unique marine environments surrounding Antarctica along with the numerous unusual interactions taking place in benthic communities are expected to select for novel functional secondary metabolites. There is an urgent need to comprehend the evolutionary role of marine derived substances in general, and particularly at the Poles, since molecules of keystone significance are vital in species survival, and therefore, in structuring the communities. Here we provide a mini-review on the identified marine natural products proven to have an ecological function in Antarctic ecosystems. This report recapitulates some of the bibliography from original Antarctic reviews, and updates the new literature in the field from 2009 to the present.

  17. Structure and stability of clusters of β-alanine in the gas phase: importance of the nature of intermolecular interactions.

    PubMed

    Piekarski, Dariusz Grzegorz; Díaz-Tendero, Sergio

    2017-02-15

    We present a theoretical study of neutral clusters of β-alanine molecules in the gas phase, (β-ala)nn ≤ 5. Classical molecular dynamics simulations carried out with different internal excitation energies provide information on the clusters formation and their thermal decomposition limits. We also present an assessment study performed with different families of density functionals using the dimer, (β-ala)2, as a benchmark system. The M06-2X functional provides the best agreement in geometries and relative energies in comparison with the reference values computed with the MP2 and CCSD(T) methods. The structure, stability, dissociation energies and vertical ionization potentials of the studied clusters have been investigated using this functional in combination with the 6-311++G(d,p) basis set. An exhaustive analysis of intermolecular interactions is also presented. These results provide new insights into the stability, interaction nature and formation mechanisms of clusters of amino acids in the gas phase.

  18. Molecular interaction between natural IgG and ficolin - mechanistic insights on adaptive-innate immune crosstalk

    NASA Astrophysics Data System (ADS)

    Panda, Saswati; Zhang, Jing; Yang, Lifeng; Anand, Ganesh S.; Ding, Jeak L.

    2014-01-01

    Recently, we found that natural IgG (nIgG; a non-specific immunoglobulin of adaptive immunity) is not quiescent, but plays a crucial role in immediate immune defense by collaborating with ficolin (an innate immune protein). However, how the nIgG and ficolin interplay and what factors control the complex formation during infection is unknown. Here, we found that mild acidosis and hypocalcaemia induced by infection- inflammation condition increased the nIgG:ficolin complex formation. Hydrogen-deuterium exchange mass spectrometry delineated the binding interfaces to the CH2-CH3 region of nIgG Fc and P-subdomain of ficolin FBG domain. Infection condition exposes novel binding sites. Site-directed mutagenesis and surface plasmon resonance analyses of peptides, derived from nIgG and ficolin, defined the interacting residues between the proteins. These results provide mechanistic insights on the interaction between two molecules representing the adaptive and innate immune pathways, prompting potential development of immunomodulatory/prophylactic peptides tunable to prevailing infection conditions.

  19. Comparing the effects of various fuel alcohols on the natural attenuation of Benzene Plumes using a general substrate interaction model

    NASA Astrophysics Data System (ADS)

    Gomez, Diego E.; Alvarez, Pedro J. J.

    2010-04-01

    The effects of five fuel alcohols (methanol, ethanol, 1-propanol, iso-butanol and n-butanol) on the natural attenuation of benzene were compared using a previously developed numerical model (General Substrate Interaction Module — GSIM) and a probabilistic sensitivity analysis. Simulations with a 30 gal dissolving LNAPL (light non-aqueous phase liquid) source consisting of a range of gasoline blends (10% and 85% v:v alcohol content) suggest that all fuel alcohols can hinder the natural attenuation of benzene, due mainly to accelerated depletion of dissolved oxygen and a decrease in the specific degradation rate for benzene (due to catabolite repression and metabolic flux dilution). Simulations for blends with 10% alcohol, assuming a homogeneous sandy aquifer, inferred maximum benzene plume elongations (relative to a regular gasoline release) of 26% for ethanol, 47% for iso-butanol, 147% for methanol, 188% for 1-propanol, and 265% for n-butanol. The corresponding elongation percentages for blends with 85% alcohol were generally smaller (i.e., 25%, 54%, 135%, 163%, and 181%, respectively), reflecting a lower content of benzene in the simulated release. Benzene plume elongation and longevity were more pronounced in the presence of alcohols that biodegrade slower (e.g., propanol and n-butanol), forming longer and more persistent alcohol plumes. Conversely, ethanol and iso-butanol exhibited the lowest potential to hinder the natural attenuation of benzene, illustrating the significant effect that a small difference in chemical structure (e.g., isomers) can have on biodegradation. Overall, simulations were highly sensitive to site-specific biokinetic coefficients for alcohol degradation, which forewarns against generalizations about the level of impact of specific fuel alcohols on benzene plume dynamics.

  20. North Atlantic Ocean OSSE system development: Nature Run evaluation and application to hurricane interaction with the Gulf Stream

    NASA Astrophysics Data System (ADS)

    Kourafalou, Vassiliki H.; Androulidakis, Yannis S.; Halliwell, George R.; Kang, HeeSook; Mehari, Michael M.; Le Hénaff, Matthieu; Atlas, Robert; Lumpkin, Rick

    2016-11-01

    A high resolution, free-running model has been developed for the hurricane region of the North Atlantic Ocean. The model is evaluated with a variety of observations to ensure that it adequately represents both the ocean climatology and variability over this region, with a focus on processes relevant to hurricane-ocean interactions. As such, it can be used as the "Nature Run" (NR) model within the framework of Observing System Simulation Experiments (OSSEs), designed specifically to improve the ocean component of coupled ocean-atmosphere hurricane forecast models. The OSSE methodology provides quantitative assessment of the impact of specific observations on the skill of forecast models and enables the comprehensive design of future observational platforms and the optimization of existing ones. Ocean OSSEs require a state-of-the-art, high-resolution free-running model simulation that represents the true ocean (the NR). This study concentrates on the development and data based evaluation of the NR model component, which leads to a reliable model simulation that has a dual purpose: (a) to provide the basis for future hurricane related OSSEs; (b) to explore process oriented studies of hurricane-ocean interactions. A specific example is presented, where the impact of Hurricane Bill (2009) on the eastward extension and transport of the Gulf Stream is analyzed. The hurricane induced cold wake is shown in both NR simulation and observations. Interaction of storm-forced currents with the Gulf Stream produced a temporary large reduction in eastward transport downstream from Cape Hatteras and had a marked influence on frontal displacement in the upper ocean. The kinetic energy due to ageostrophic currents showed a significant increase as the storm passed, and then decreased to pre-storm levels within 8 days after the hurricane advanced further north. This is a unique result of direct hurricane impact on a western boundary current, with possible implications on the ocean

  1. Rethinking Giftedness and Talent in Sport

    ERIC Educational Resources Information Center

    Tranckle, Peter; Cushion, Christopher J.

    2006-01-01

    The purpose of this paper is to understand how gifts are discovered and talents developed within sport. The current literature is critically discussed, highlighting contributions and gaps in current knowledge. Due to issues concerning terminology and the nature versus nurture debate, research on talent faces challenges relating to continuity and…

  2. Rethinking Recycling: An Oregon Waste Reduction Curriculum.

    ERIC Educational Resources Information Center

    Oregon State Dept. of Environmental Quality, Portland.

    This updated curriculum guide is designed to provide teachers of elementary school science with a set of activities on recycling and waste reduction. The curriculum has three sections: (1) Grades K-3 Lessons; (2) Grades 4-5 Lessons; and (3) Teacher's Resource Guide. It is designed to take students from an introduction to natural resources and…

  3. Rethinking Education--Emerging Roles for Teachers

    ERIC Educational Resources Information Center

    Dar, Fatima Rehan

    2015-01-01

    The purpose of the study was to find out how teachers role modeled and taught empathetic and pro-social skills at the primary level. The study was qualitative in nature and followed a case study approach. Observations of regular English language classes were done from Grades 1-5 to see if class lessons incorporated the said themes and whether…

  4. Sharing the Caring: Rethinking Current Policies.

    ERIC Educational Resources Information Center

    Edgar, Don

    1992-01-01

    This article presents an argument for reforming Australian public policy in favor of social care, rather than family, residential, or community care, for the elderly, sick, and disabled. After noting policy assumptions that families are the focus of caring and women are the natural caregivers, the paper describes changes in Australian family…

  5. Rethinking School Discipline through Effective Behavioral Support.

    ERIC Educational Resources Information Center

    Lewis, Timothy J.; Daniels, Carol

    2000-01-01

    Identifies three strategies for reducing challenging behaviors in students. They include teaching parents how to interact with their children in order to set limits, social skills training for students, and insuring a measure of academic success for the students. Advocates a three-tiered schoolwide prevention and intervention. (Author/JDM)

  6. Rethinking a Right Hemisphere Deficit in ADHD

    ERIC Educational Resources Information Center

    Hale, T. Sigi; Loo, Sandra K.; Zaidel, Eran; Hanada, Grant; Macion, James; Smalley, Susan L.

    2009-01-01

    Introduction: Early observations from lesion studies suggested right hemisphere (RH) dysfunction in ADHD. However, a strictly right-lateralized deficit has not been well supported. An alternatively view suggests increased R greater than L asymmetry of brain function and abnormal interhemispheric interaction. If true, RH pathology in ADHD should…

  7. Rational design of carbonitrile-carboxaldehyde cation receptor models: probing the nature of the heteroatom-metal interaction.

    PubMed

    Rosli, Ahmad Nazmi; Abu Bakar, Maizathul Akmam; Lee, Vannajan Sanghiran; Zain, Sharifuddin Md; Ahmad, Mohd Rais; Abdul Manan, Ninie Suhana; Alias, Yatimah; Woi, Pei Meng

    2014-09-01

    In this work, hybrid functional and G4 methods were employed in the rational design of carbonitrile-carboxaldehyde receptor models for cation recognition. Electron-sharing and ionic interactions between the models and the cations were analyzed utilizing the concepts of overlap population, atomic valence, electrostatic potential, and CHELPG charge in order to elucidate the nature of the heteroatom-metal interaction, the N versus O disparity, and the effect of pH. Receptor fragment models from ionomycin were employed to rationalize the selection of receptor models for discriminating group I cations and enhancing the selectivity for Mg(II) rather than Ca(II), and to examine the effects of keto-enol forms and negatively charged sites. The changes in geometries, overlap population, metal valence, and CHELPG charge upon solvation in heptane medium as compared to the gas phase were negligible. The optimized geometries reveal that the interaction between group II cations and the keto, enol, and enolate forms of 2-cyanoethanal causes 12 % bending of the C-C-N angle from linearity. Overlap populations show that the electron-sharing interaction favors group II cations but that the same mechanism allows Li(I) to compete. The total spin of Li(I) is 17 % greater than that of Ca(II), but the G4 binding energies of the two are separated by more than 50 kcal/mol, favoring group II cations, which may eliminate interference from Li(I). 1,2-Dicyanoethylene, which has only one form, shows similar characteristics. CHELPG analysis shows that Mg(II) transfers 25 and 18 % of its positive charge to 2-cyanoethanal enolate and 1,2-dicyanoethylene, respectively. Hydrogen atoms receive most of the positive charge in both receptors, but the N-termini exhibit strikingly different characteristics. Electrostatic potential contour profiles were found to be in good agreement with the atomic charge distributions. The application of uncharged 1,3-dicarbonyl and 2-cyanocarbonyl receptors and a judicious

  8. Multi-isotope tracing of CO2 leakage and water-rock interaction in a natural CCS analogue.

    NASA Astrophysics Data System (ADS)

    Kloppmann, Wolfram; Gemeni, Vasiliki; Lions, Julie; Koukouzas, Nikolaos; Humez, Pauline; Vasilatos, Charalampos; Millot, Romain; Pauwels, Hélène

    2015-04-01

    Natural analogues of CO2 accumulation and, potentially, leakage, provide a highly valuable opportunity to study (1) geochemical processes within a CO2-reservoir and the overlying aquifers or aquicludes, i.e. gas-water-rock interactions, (2) geology and tightness of reservoirs over geological timescales, (3) potential or real leakage pathways, (3) impact of leakage on shallow groundwater resources quality, and (4) direct and indirect geochemical indicators of gas leakage (Lions et al., 2014, Humez et al., 2014). The Florina Basin in NW Macedonia, Greece, contains a deep CO2-rich aquifer within a graben structure. The graben filling consists of highly heterogeneous Neogene clastic sediments constituted by components from the adjacent massifs including carbonates, schists, gneiss as well as some ultramafic volcanic rocks. Clay layers are observed that isolate hydraulically the deep, partly artesian aquifer. Organic matter, in form of lignite accumulations, is abundant in the Neogene series. The underlying bedrocks are metamorphic carbonates and silicate rocks. The origin of the CO2 accumulation is controversial (deep, partially mantle-derived D'Allessandro et al., 2008 or resulting from thermal decomposition of carbonates, Hatziyannis and Arvanitis, 2011). Groundwaters have been sampled from springs and borewells over 3 years at different depths. First results on major, minor and trace elements give evidence of water-rock interaction, mainly with carbonates but also with ultramafic components but do not indicate that CO2-seepage is the principal driver of those processes (Gemeni et al., submitted). Here we present isotope data on a selection of groundwaters (δ2H , δ18O, δ13CTDIC, 87Sr/86Sr, δ11B, δ7Li). Stable isotopes of water indicate paleo-recharge for some of the groundwaters, limited exchange with gaseous CO2 and, in one case, possibly thermal exchange processes with silicates. Sr isotope ratios vary between marine ratios and radiogenic values indicating

  9. Assessing the interactions of a natural antibacterial clay with model Gram-positive and Gram-negative human pathogens

    NASA Astrophysics Data System (ADS)

    Londono, S. C.; Williams, L. B.

    2013-12-01

    The emergence of antibiotic resistant bacteria and increasing accumulations of antibiotics in reclaimed water, drive the quest for new natural antimicrobials. We are studying the antibacterial mechanism(s) of clays that have shown an ability to destroy bacteria or significantly inhibit their growth. One possible mode of action is from soluble transition metal species, particularly reduced Fe, capable of generating deleterious oxygen radical species. Yet another possibility is related to membrane damage as a consequence of physical or electrostatic interaction between clay and bacteria. Both mechanisms could combine to produce cell death. This study addresses a natural antibacterial clay from the NW Amazon basin, South America (AMZ clay). Clay mineralogy is composed of disordered kaolinite (28.9%), halloysite (17.8%) illite (12%) and smectite (16.7%). Mean particle size is 1.6μm and total and specific surface area 278.82 and 51.23 m2/g respectively. The pH of a suspension (200mg/ml) is 4.1 and its Eh is 361mV after 24h of equilibration. The ionic strength of the water in equilibrium with the clay after 24 h. is 6 x10-4M. These conditions, affect the element solubility, speciation, and interactions between clay and bacteria. Standard microbiological methods were used to assess the viability of two model bacteria (Escherichia coli and Bacillus subtilis) after incubation with clay at 37 degC for 24 hrs. A threefold reduction in bacterial viability was observed upon treatment with AMZ clay. We separated the cells from the clay using Nycodenz gradient media and observed the mounts under the TEM and SEM. Results showed several membrane anomalies and structural changes that were not observed in the control cells. Additionally, clay minerals appeared in some places attached to cell walls. Experiments showed that exchanging AMZ clay with KCl caused loss of antibacterial property. Among the exchangeable -and potentially toxic- ions we measured Al+3, Cu+2, Zn+2, Ba+2 and Co+2

  10. The interaction of natural background gamma radiation with depleted uranium micro-particles in the human body.

    PubMed

    Pattison, John E

    2013-03-01

    In this study, some characteristics of the photo-electrons produced when natural background gamma radiation interacts with micron-sized depleted uranium (DU) particles in the human body have been estimated using Monte Carlo simulations. In addition, an estimate has been made of the likelihood of radiological health effects occurring due to such an exposure. Upon exposure to naturally occurring background gamma radiation, DU particles in the body will produce an enhancement of the dose to the tissue in the immediate vicinity of the particles due to the photo-electric absorption of the radiation in the particle. In this study, the photo-electrons produced by a 10 μm-size particle embedded in tissue at the centre of the human torso have been investigated. The mean energies of the photo-electrons in the DU particle and in the two consecutive immediately surrounding 2 μm-wide tissue shells around the particle were found to be 38, 49 and 50 keV, respectively, with corresponding ranges of 1.3, 38 and 39 μm, respectively. The total photo-electron fluence-rates in the two consecutive 2 μm-wide tissue layers were found to be 14% and 7% of the fluence-rate in the DU particle, respectively. The estimated dose enhancement due to one 10 μm-sized DU particle in 1 cm(3) of tissue was less than 2 in 10 million of the dose received by the tissue without a particle being present. The increase in risk of death from cancer due to this effect is consequently insignificant.

  11. Natural frequencies, modeshapes and modal interactions for strings vibrating against an obstacle: Relevance to Sitar and Veena

    NASA Astrophysics Data System (ADS)

    Mandal, A. K.; Wahi, P.

    2015-03-01

    We study the vibration characteristics of a string with a smooth unilateral obstacle placed at one of the ends similar to the strings in musical instruments like sitar and veena. In particular, we explore the correlation between the string vibrations and some unique sound characteristics of these instruments like less inharmonicity in the frequencies, a large number of overtones and the presence of both frequency and amplitude modulations. At the obstacle, we have a moving boundary due to the wrapping of the string and an appropriate scaling of the spatial variable leads to a fixed boundary at the cost of introducing nonlinearity in the governing equation. Reduced order system of equations has been obtained by assuming a functional form for the string displacement which satisfies all the boundary conditions and gives the free length of the string in terms of the modal coordinates. To study the natural frequencies and mode-shapes, the nonlinear governing equation is linearized about the static configuration. The natural frequencies have been found to be harmonic and they depend on the shape of the obstacle through the effective free length of the string. Expressions have been obtained for the time-varying mode-shapes as well as the variation of the nodal points. Modal interactions due to coupling have been studied which show the appearance of higher overtones as well as amplitude modulations in our theoretical model akin to the experimental observations. All the obtained results have been verified with an alternate formulation based on the assumed mode method with polynomial shape functions.

  12. Nonequilibrium thermodynamics of interacting tunneling transport: variational grand potential, density functional formulation and nature of steady-state forces.

    PubMed

    Hyldgaard, P

    2012-10-24

    The standard formulation of tunneling transport rests on an open-boundary modeling. There, conserving approximations to nonequilibrium Green function or quantum statistical mechanics provide consistent but computational costly approaches; alternatively, the use of density-dependent ballistic-transport calculations (e.g., Lang 1995 Phys. Rev. B 52 5335), here denoted 'DBT', provides computationally efficient (approximate) atomistic characterizations of the electron behavior but has until now lacked a formal justification. This paper presents an exact, variational nonequilibrium thermodynamic theory for fully interacting tunneling and provides a rigorous foundation for frozen-nuclei DBT calculations as a lowest-order approximation to an exact nonequilibrium thermodynamic density functional evaluation. The theory starts from the complete electron nonequilibrium quantum statistical mechanics and I identify the operator for the nonequilibrium Gibbs free energy which, generally, must be treated as an implicit solution of the fully interacting many-body dynamics. I demonstrate a minimal property of a functional for the nonequilibrium thermodynamic grand potential which thus uniquely identifies the solution as the exact nonequilibrium density matrix. I also show that the uniqueness-of-density proof from a closely related Lippmann-Schwinger collision density functional theory (Hyldgaard 2008 Phys. Rev. B 78 165109) makes it possible to express the variational nonequilibrium thermodynamic description as a single-particle formulation based on universal electron-density functionals; the full nonequilibrium single-particle formulation improves the DBT method, for example, by a more refined account of Gibbs free energy effects. I illustrate a formal evaluation of the zero-temperature thermodynamic grand potential value which I find is closely related to the variation in the scattering phase shifts and hence to Friedel density oscillations. This paper also discusses the

  13. Grazing-induced effects on soil properties modify plant competitive interactions in semi-natural mountain grasslands.

    PubMed

    Medina-Roldán, Eduardo; Paz-Ferreiro, Jorge; Bardgett, Richard D

    2012-09-01

    Plant-soil feedbacks are widely recognized as playing a significant role in structuring plant communities through their effects on plant-plant interactions. However, the question of whether plant-soil feedbacks can be indirectly driven by other ecological agents, such as large herbivores, which are known to strongly modify plant community structure and soil properties, remains poorly explored. We tested in a glasshouse experiment how changes in soil properties resulting from long-term sheep grazing affect competitive interactions (intra- and inter-specific) of two graminoid species: Nardus stricta, which is typically abundant under high sheep grazing pressure in British mountain grasslands; and Eriophorum vaginatum, whose abundance is typically diminished under grazing. Both species were grown in monocultures and mixtures at different densities in soils taken from adjacent grazed and ungrazed mountain grassland in the Yorkshire Dales, northern England. Nardus stricta performed better (shoot and root biomass) when grown in grazing-conditioned soil, independent of whether or not it grew under inter-specific competition. Eriophorum vaginatum also grew better when planted in soil from the grazed site, but this occurred only when it did not experience inter-specific competition with N. stricta. This indicates that plant-soil feedback for E. vaginatum is dependent on the presence of an inter-specific competitor. A yield density model showed that indirect effects of grazing increased the intensity of intra-specific competition in both species in comparison with ungrazed-conditioned soil. However, indirect effects of grazing on the intensity of inter-specific competition were species-specific favouring N. stricta. We explain these asymmetric grazing-induced effects on competition on the basis of traits of the superior competitor and grazing effects on soil nutrients. Finally, we discuss the relevance of our findings for plant community dynamics in grazed, semi-natural

  14. Nonequilibrium thermodynamics of interacting tunneling transport: variational grand potential, density functional formulation and nature of steady-state forces

    NASA Astrophysics Data System (ADS)

    Hyldgaard, P.

    2012-10-01

    The standard formulation of tunneling transport rests on an open-boundary modeling. There, conserving approximations to nonequilibrium Green function or quantum statistical mechanics provide consistent but computational costly approaches; alternatively, the use of density-dependent ballistic-transport calculations (e.g., Lang 1995 Phys. Rev. B 52 5335), here denoted ‘DBT’, provides computationally efficient (approximate) atomistic characterizations of the electron behavior but has until now lacked a formal justification. This paper presents an exact, variational nonequilibrium thermodynamic theory for fully interacting tunneling and provides a rigorous foundation for frozen-nuclei DBT calculations as a lowest-order approximation to an exact nonequilibrium thermodynamic density functional evaluation. The theory starts from the complete electron nonequilibrium quantum statistical mechanics and I identify the operator for the nonequilibrium Gibbs free energy which, generally, must be treated as an implicit solution of the fully interacting many-body dynamics. I demonstrate a minimal property of a functional for the nonequilibrium thermodynamic grand potential which thus uniquely identifies the solution as the exact nonequilibrium density matrix. I also show that the uniqueness-of-density proof from a closely related Lippmann-Schwinger collision density functional theory (Hyldgaard 2008 Phys. Rev. B 78 165109) makes it possible to express the variational nonequilibrium thermodynamic description as a single-particle formulation based on universal electron-density functionals; the full nonequilibrium single-particle formulation improves the DBT method, for example, by a more refined account of Gibbs free energy effects. I illustrate a formal evaluation of the zero-temperature thermodynamic grand potential value which I find is closely related to the variation in the scattering phase shifts and hence to Friedel density oscillations. This paper also discusses the

  15. Compact two-electron wave function for bond dissociation and Van der Waals interactions: A natural amplitude assessment

    SciTech Connect

    Giesbertz, Klaas J. H.; Leeuwen, Robert van

    2014-05-14

    Electron correlations in molecules can be divided in short range dynamical correlations, long range Van der Waals type interactions, and near degeneracy static correlations. In this work, we analyze for a one-dimensional model of a two-electron system how these three types of correlations can be incorporated in a simple wave function of restricted functional form consisting of an orbital product multiplied by a single correlation function f (r{sub 12}) depending on the interelectronic distance r{sub 12}. Since the three types of correlations mentioned lead to different signatures in terms of the natural orbital (NO) amplitudes in two-electron systems, we make an analysis of the wave function in terms of the NO amplitudes for a model system of a diatomic molecule. In our numerical implementation, we fully optimize the orbitals and the correlation function on a spatial grid without restrictions on their functional form. Due to this particular form of the wave function, we can prove that none of the amplitudes vanishes and moreover that it displays a distinct sign pattern and a series of avoided crossings as a function of the bond distance in agreement with the exact solution. This shows that the wave function ansatz correctly incorporates the long range Van der Waals interactions. We further show that the approximate wave function gives an excellent binding curve and is able to describe static correlations. We show that in order to do this the correlation function f (r{sub 12}) needs to diverge for large r{sub 12} at large internuclear distances while for shorter bond distances it increases as a function of r{sub 12} to a maximum value after which it decays exponentially. We further give a physical interpretation of this behavior.

  16. Particle coating-dependent interaction of molecular weight fractionated natural organic matter: impacts on the aggregation of silver nanoparticles.

    PubMed

    Yin, Yongguang; Shen, Mohai; Tan, Zhiqiang; Yu, Sujuan; Liu, Jingfu; Jiang, Guibin

    2015-06-02

    Ubiquitous natural organic matter (NOM) plays an important role in the aggregation state of engineered silver nanoparticles (AgNPs) in aquatic environment, which determines the transport, transformation, and toxicity of AgNPs. As various capping agents are used as coatings for nanoparticles and NOM are natural polymer mixture with wide molecular weight (MW) distribution, probing the particle coating-dependent interaction of MW fractionated natural organic matter (Mf-NOM) with various coatings is helpful for understanding the differential aggregation and transport behavior of engineered AgNPs as well as other metal nanoparticles. In this study, we investigated the role of pristine and Mf-NOM on the aggregation of AgNPs with Bare, citrate, and PVP coating (Bare-, Cit-, and PVP-AgNP) in mono- and divalent electrolyte solutions. We observed that the enhanced aggregation or dispersion of AgNPs in NOM solution highly depends on the coating of AgNPs. Pristine NOM inhibited the aggregation of Bare-AgNPs but enhanced the aggregation of PVP-AgNPs. In addition, Mf-NOM fractions have distinguishing roles on the aggregation and dispersion of AgNPs, which also highly depend on the AgNPs coating as well as the MW of Mf-NOM. Higher MW Mf-NOM (>100 kDa and 30-100 kDa) enhanced the aggregation of PVP-AgNPs in mono- and divalent electrolyte solutions, whereas lower MW Mf-NOM (10-30 kDa, 3-10 kDa and <3 kDa) inhibited the aggregation of PVP-AgNPs. However, all the Mf-NOM fractions inhibited the aggregation of Bare-AgNPs. For PVP- and Bare-AgNPs, the stability of AgNPs in electrolyte solution was significantly correlated to the MW of Mf-NOM. But for Cit-AgNPs, pristine NOM and Mf-NOM has minor influence on the stability of AgNPs. These findings about significantly different roles of Mf-NOM on aggregation of engineered AgNPs with various coating are important for better understanding of the transport and subsequent transformation of AgNPs in aquatic environment.

  17. Aerosol-halogen interaction: Change of physico-chemical properties of SOA by naturally released halogen species

    NASA Astrophysics Data System (ADS)

    Ofner, J.; Balzer, N.; Buxmann, J.; Grothe, H.; Krüger, H.; Platt, U.; Schmitt-Kopplin, P.; Zetzsch, C.

    2011-12-01

    Reactive halogen species are released by various sources like photo-activated sea-salt aerosol or salt pans and salt lakes. These heterogeneous release mechanisms have been overlooked so far, although their potential of interaction with organic aerosols like Secondary Organic Aerosol (SOA), Biomass Burning Organic Aerosol (BBOA) or Atmospheric Humic LIke Substances (HULIS) is completely unknown. Such reactions can constitute sources of gaseous organo-halogen compounds or halogenated organic particles in the atmospheric boundary layer. To study the interaction of organic aerosols with reactive halogen species (RHS), SOA was produced from α-pinene, catechol and guaiacol using an aerosol smog-chamber. The model SOAs were characterized in detail using a variety of physico-chemical methods (Ofner et al., 2011). Those aerosols were exposed to molecular halogens in the presence of UV/VIS irradiation and to halogens, released from simulated natural halogen sources like salt pans, in order to study the complex aerosol-halogen interaction. The heterogeneous reaction of RHS with those model aerosols leads to different gaseous species like CO2, CO and small reactive/toxic molecules like phosgene (COCl2). Hydrogen containing groups on the aerosol particles are destroyed to form HCl or HBr, and a significant formation of C-Br bonds could be verified in the particle phase. Carbonyl containing functional groups of the aerosol are strongly affected by the halogenation process. While changes of functional groups and gaseous species were visible using FTIR spectroscopy, optical properties were studied using Diffuse Reflectance UV/VIS spectroscopy. Overall, the optical properties of the processed organic aerosols are significantly changed. While chlorine causes a "bleaching" of the aerosol particles, bromine shifts the maximum of UV/VIS absorption to the red end of the UV/VIS spectrum. Further physico-chemical changes were recognized according to the aerosol size-distributions or the

  18. Rethinking differentiation: Stem cells, regeneration, and plasticity

    PubMed Central

    Alvarado, Alejandro Sánchez; Yamanaka, Shinya

    2014-01-01

    Cell differentiation is an essential process for the development, growth, reproduction and longevity of all multicellular organisms, and its regulation has been the focus of intense investigation for the past 4 decades. The study of natural and induced stem cells has ushered an age of re-examination of what it means to be a stem or a differentiated cell. Past and recent discoveries in plants and animals, as well as novel experimental manipulations are beginning to erode many of these established concepts, and are forcing a re-evaluation of the experimental systems and paradigms presently being used to explore these and other biological process. PMID:24679530

  19. Starch and natural rubber allergen interaction in the production of latex gloves: a hand-held aerosol.

    PubMed

    Swanson, Mark C; Ramalingam, Mohan

    2002-08-01

    Starch powders continue to be used as donning agents on natural rubber (NR) gloves. NR aeroallergens are an important aspect of human sensitivity to latex. Asthma, upper airway, and ocular symptoms are associated with these airborne proteins. These bioaerosols feature starch as the carrier. The association of NR allergen and starch is demonstrated in NR glove manufacturing, in laboratory simulation, and as occupational aeroallergens in health care environments. Four aspects of latex allergen affinity for starch powders were examined by using a competitive IgE immunoassay for NR latex. Allergen content was assessed in finished gloves before and after powder process points and related to the allergen content of the raw latex source material. In another manufacturing process, allergen uptake by two different starch powders was quantified. NR allergen affinity for the starches was also determined under laboratory conditions. Finally, NR aeroallergens carried by starch powder in production facilities were measured. This article outlines the sources, mechanisms, and conditions for NR allergens to interact with two different starches. The quantitative airborne allergen data are used to compare and contrast various occupational indices of NR allergen exposure. Powdered NR gloves continue to cause concern; however, the technology used for contemporary glove powder applications may be advanced and improved enough to consistently produce powdered gloves with a low allergen content.

  20. Improvement of interfacial interactions using natural polyphenol-inspired tannic acid-coated nanoclay enhancement of soy protein isolate biofilms

    NASA Astrophysics Data System (ADS)

    Wang, Zhong; Kang, Haijiao; Zhang, Wei; Zhang, Shifeng; Li, Jianzhang

    2017-04-01

    In this study, a novel and economic surface modification technique for montmorillonite (MMT) nanosheets, a biocompatible coupling cross-linking agent, was developed on an attempt at improving the interfacial adhesion with soy protein isolate (SPI) matrix. Inspired by natural polyphenol, the "green dip-coating" method using tannic acid (TA) to surface-modify MMT (TA@MMT). SPI nanocomposite films modified with MMT or TA@MMT, as well as the control ones, were prepared via the casting method. The TA layer was successfully coated on the MMT surface through the (FeIII) ions coordination chemistry and the synthetic samples were characterized by the Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The compatibility and interfacial interactions between modified MMT and SPI matrix were greatly enhanced by the TA-FeIII coating on the MMT surface. The mechanical properties, water resistance, and thermal stability of the resultant biofilm were increased accordingly. Compared with that of the unmodified SPI film, the tensile strength of the nanocomposite films modified by the green dip-coating was increased by 113.3%. These SPI-based nanocomposite films showed the favorable potential in terms of food packing applications due to their efficient barriers to water vapor and UV and/or visible light.

  1. The interaction of domain knowledge and linguistic structure in natural language processing: interpreting hypernymic propositions in biomedical text.

    PubMed

    Rindflesch, Thomas C; Fiszman, Marcelo

    2003-12-01

    Interpretation of semantic propositions in free-text documents such as MEDLINE citations would provide valuable support for biomedical applications, and several approaches to semantic interpretation are being pursued in the biomedical informatics community. In this paper, we describe a methodology for interpreting linguistic structures that encode hypernymic propositions, in which a more specific concept is in a taxonomic relationship with a more general concept. In order to effectively process these constructions, we exploit underspecified syntactic analysis and structured domain knowledge from the Unified Medical Language System (UMLS). After introducing the syntactic processing on which our system depends, we focus on the UMLS knowledge that supports interpretation of hypernymic propositions. We first use semantic groups from the Semantic Network to ensure that the two concepts involved are compatible; hierarchical information in the Metathesaurus then determines which concept is more general and which more specific. A preliminary evaluation of a sample based on the semantic group Chemicals and Drugs provides 83% precision. An error analysis was conducted and potential solutions to the problems encountered are presented. The research discussed here serves as a paradigm for investigating the interaction between domain knowledge and linguistic structure in natural language processing, and could also make a contribution to research on automatic processing of discourse structure. Additional implications of the system we present include its integration in advanced semantic interpretation processors for biomedical text and its use for information extraction in specific domains. The approach has the potential to support a range of applications, including information retrieval and ontology engineering.

  2. CD34+ hematopoietic precursors are present in human decidua and differentiate into natural killer cells upon interaction with stromal cells

    PubMed Central

    Vacca, Paola; Vitale, Chiara; Montaldo, Elisa; Conte, Romana; Cantoni, Claudia; Fulcheri, Ezio; Darretta, Valeria; Moretta, Lorenzo; Mingari, Maria Cristina

    2011-01-01

    Natural killer (NK) cells are the main lymphoid population in the maternal decidua during the first trimester of pregnancy. Decidual NK (dNK) cells display a unique functional profile and play a key role in promoting tissue remodeling, neoangiogenesis, and immune modulation. However, little information exists on their origin and development. Here we discovered CD34+ hematopoietic precursors in human decidua (dCD34+). We show that dCD34+ cells differ from cord blood- or peripheral blood-derived CD34+ precursors. The expression of IL-15/IL-2 receptor common β-chain (CD122), IL-7 receptor α-chain (CD127), and mRNA for E4BP4 and ID2 transcription factors suggested that dCD34+ cells are committed to the NK cell lineage. Moreover, they could undergo in vitro differentiation into functional (i.e., IL-8– and IL-22–producing) CD56brightCD16−KIR+/− NK cells in the presence of growth factors or even upon coculture with decidual stromal cells. Their NK cell commitment was further supported by the failure to undergo myeloid differentiation in the presence of GM-CSF. Our findings strongly suggest that decidual NK cells may directly derive from CD34+ cell precursors present in the decidua upon specific cellular interactions with components of the decidual microenvironment. PMID:21248224

  3. The isolation, total synthesis and structure elucidation of chlorofusin, a natural product inhibitor of the p53-MDM2 protein-protein interaction

    PubMed Central

    Clark, Ryan C.; Lee, Sang Yeul; Searcey, Mark; Boger, Dale L.

    2009-01-01

    Inhibitors of key protein-protein interactions are emerging as exciting therapeutic targets for the treatment of cancer. One such interaction between MDM2 (HDM2) and p53, that silences the tumour suppression activities of p53, was found to be inhibited by the recently isolated natural product chlorofusin. Synthetic studies on this complex natural product summarized herein have served to reassign its chromophore relative stereochemistry, assign its absolute stereochemistry, and provided access to a series of key analogues and partial structures for biological evaluation. PMID:19642417

  4. Comparing the peroxo/superoxo nature of the interaction between molecular O2 and β-diketiminato-copper and nickel complexes.

    PubMed

    Zapata-Rivera, Jhon; Caballol, Rosa; Calzado, Carmen J

    2011-12-07

    Adducts resulting from the interaction between molecular oxygen and β-diketiminato-copper and nickel complexes have been recently described in the literature as peroxo and superoxo complexes, respectively. The nature of the interaction is analyzed by means of DDCI calculations and an orthogonal valence bond reading of the ground state wavefunction for each system. Our results reveal that there is not any substantial difference between these systems, both presenting a marked leading superoxo nature, which is in line with the fact that LCu-O(2) and LNi-O(2) adducts present similar O-O distances and quite close O-O stretching vibration modes.

  5. Rethinking vulnerability analysis and governance with emphasis on a participatory approach.

    PubMed

    Rossignol, Nicolas; Delvenne, Pierre; Turcanu, Catrinel

    2015-01-01

    This article draws on vulnerability analysis as it emerged as a complement to classical risk analysis, and it aims at exploring its ability for nurturing risk and vulnerability governance actions. An analysis of the literature on vulnerability analysis allows us to formulate a three-fold critique: first, vulnerability analysis has been treated separately in the natural and the technological hazards fields. This separation prevents vulnerability from unleashing the full range of its potential, as it constrains appraisals into artificial categories and thus already closes down the outcomes of the analysis. Second, vulnerability analysis focused on assessment tools that are mainly quantitative, whereas qualitative appraisal is a key to assessing vulnerability in a comprehensive way and to informing policy making. Third, a systematic literature review of case studies reporting on participatory approaches to vulnerability analysis allows us to argue that participation has been important to address the above, but it remains too closed down in its approach and would benefit from embracing a more open, encompassing perspective. Therefore, we suggest rethinking vulnerability analysis as one part of a dynamic process between opening-up and closing-down strategies, in order to support a vulnerability governance framework.

  6. Rethinking global health research: towards integrative expertise

    PubMed Central

    MacLachlan, Malcolm

    2009-01-01

    The Bamako Call for Action on Research for Health stresses the importance of inter-disciplinary, inter-ministerial and inter-sectoral working. This challenges much of our current research and postgraduate research training in health, which mostly seeks to produce narrowly focused content specialists. We now need to compliment this type of research and research training, by offering alternative pathways that seek to create expertise, not only in specific narrow content areas, but also in the process and context of research, as well as in the interaction of these different facets of knowledge. Such an approach, developing 'integrative expertise', could greatly facilitate better research utilisation, helping policy makers and practitioners work through more evidence-based practice and across traditional research boundaries. PMID:19643021

  7. Democracy and environment: Rethinking our educational priorities

    NASA Astrophysics Data System (ADS)

    Goodlad, Stephen John

    Two groups of scholars have recently pined prominence. Both are concerned about what is taught in America's schools and how it is taught. One group is focused on the need to strengthen a democracy they see as weakening and under attack. A second is concerned about an impending ecological catastrophe. These two concerns are often regarded as separate, unrelated, even conflicting. This paper argues that democracy and environmental issues actually have much in common; that both are fundamentally concerned with relationships and both are threatened in similar ways, for similar reasons. Moreover, if fully and property understood, these two crises can be recognized as mere symptoms of a much deeper crisis of modern, industrialized cultures, which are defined as vast, paradigmatic "super-cultures" that share enough in common that they can be seen as unique in their own right. To address this cultural crisis will require deliberate, widespread intervention. This intervention should begin in our public schools: first, because a major purpose of public education is enculturation. Second, educators have moral and ethical obligations that suggest that such intervention is justified, perhaps even imperative. If public education is to play a proactive role in our cultural evolution, sweeping curricular and pedagogical reforms will be necessary. Cultural issues cannot be separated from other aspects of a curriculum, or set aside as a separate discipline. Therefore fundamental curricular and pedagogical changes will need to be made throughout the entire educational system. Democracy (how we interact with one another) and environment (how we interact with the world around us) ought to form the foundational priorities on which all such reforms rest. An undertaking of this magnitude will encounter a great many obstacles. Some of the most prominent of those obstacles are assessed and serve as broad indicators of certain key areas in which reform efforts might be initiated. Finally

  8. Rethinking Environmental Protection: Meeting the Challenges ...

    EPA Pesticide Factsheets

    Background: The U.S. Environmental Protection Agency (EPA) has made great progress in addressing some major environmental problems. These successes were framed within EPA’s statutory mandates which are largely media-specific and receptor-focused and follow a segmented risk-based construct. Today’s environmental problems are increasingly complex, and new approaches are needed to achieve sustainable solutions that protect the environment and public health. Objectives: We provide an overview of environmental protection at EPA and highlight today’s environmental challenges. We provide case examples of systems approaches that consider the links between environment and human health. We offer a strategic framework for tackling challenges so EPA can continue to protect the environment and public health.Discussion: Expanded approaches will be transdisciplinary, informed by vast new sources of data, and build upon new stakeholder partnerships. A systems approach to environmental protection looks at problems holistically, includes the drivers and stressors that impact the issue and the dimensions that frame it, and integrates various types of data from health, ecological, and social sciences, with the goal of formulating sustainable solutions to environmental issues. Conclusions: The natural environment and human health are inextricably linked, and human health, well-being, and economic prosperity depend on healthy ecosystems. EPA research is leading an evolution in

  9. Rethinking the INN system for therapeutic antibodies

    PubMed Central

    Pottier, Jérémy; Chastang, Romane; Dumet, Christophe; Watier, Hervé

    2017-01-01

    ABSTRACT In the context of a possible revision of the International Nonproprietary Names (INN) system of recombinant monoclonal antibodies, which is saturated, we propose several avenues of reflection driven by the primary goal of the INN, information of health-care professionals. Clinical considerations argue for an abandon of the substems A (target category) and B (origin category), which lengthen the INN without real added-value. On the contrary, new substems or suffixes are required to alert on the absence/presence of an Fc portion and/or multispecificity, which are essential from a pharmacological point of view. Moreover, we think it necessary to explicitly mention Fc variations since they could influence the pharmacology of these biopharmaceuticals, and hence their efficacy and side-effects. Besides indicating the subclass/isotype in the documents easily accessible to health care professionals, we propose to systematically describe both the natural variations (allotypes) by using the Gm (G marker) system, and the artificial variations by using a Ge (G engineering) system that is discussed here and could apply to all IgG constant domains (tentatively called the Fy portion). PMID:27808597

  10. Evidence for chemical bond formation at rubber-brass interface: Photoelectron spectroscopy study of bonding interaction between copper sulfide and model molecules of natural rubber

    NASA Astrophysics Data System (ADS)

    Ozawa, Kenichi; Mase, Kazuhiko

    2016-12-01

    Strong adhesion between rubber and brass has been considered to arise mainly from the mechanical interaction, which is characterized by dendritic interlocking at the interface. In order to examine a possible contribution of the chemical interaction, chemical state analysis was carried out for model molecules of natural rubber (2-methyl-2-butene and isoprene) adsorbed on Cu2S, a key chemical species for adhesion, by means of photoelectron spectroscopy (PES). Absence of a C 1s PES component associated with C=C bonds and the appearance of adsorption-induced components in the S 2p region indicate that the molecules interact with the Cu2S surface via the C=C bond to form C-S covalent bonds. This proves that the chemical interaction certainly plays a role in rubber-brass adhesion along with the mechanical interaction.

  11. Particle-image velocimetry investigation of the fluid-structure interaction mechanisms of a natural owl wing.

    PubMed

    Winzen, A; Roidl, B; Schröder, W

    2015-09-15

    The increasing interest in the development of small flying air vehicles has given rise to a strong need to thoroughly understand low-speed aerodynamics. The barn owl is a well-known example of a biological system that possesses a high level of adaptation to its habitat and as such can inspire future small-scale air vehicle design. The combination of the owl-specific wing geometry and plumage adaptations with the flexibility of the wing structure yields a highly complex flow field, still enabling the owl to perform stable and at the same time silent low-speed gliding flight. To investigate the effects leading to such a characteristic flight, time-resolved stereoscopic particle-image velocimetry (TR-SPIV) measurements are performed on a prepared natural owl wing in a range of angles of attack 0° ≤ α ≤ 6° and Reynolds numbers 40,000 ≤ Re(c) ≤ 120,000 based on the chord length at a position located at 30% of the halfspan from the owl's body. The flow field does not show any flow separation on the suction side, whereas flow separation is found on the pressure side for all investigated cases. The flow field on the pressure side is characterized by large-scale vortices which interact with the flexible wing structure. The good agreement of the shedding frequency of the pressure side vortices with the frequency of the trailing-edge deflection indicates that the structural deformation is induced by the flow field on the pressure side. Additionally, the reduction of the time-averaged mean wing curvature at high Reynolds numbers indicates a passive lift-control mechanism that provides constant lift in the entire flight envelope of the owl.

  12. Acceleration of wound healing by α-gal nanoparticles interacting with the natural anti-Gal antibody.

    PubMed

    Galili, Uri

    2015-01-01

    Application of α-gal nanoparticles to wounds and burns induces accelerated healing by harnessing the natural anti-Gal antibody which constitutes ~1% of human immunoglobulins. α-gal nanoparticles present multiple α-gal epitopes (Galα1-3Galβ1-4GlcNAc-R), the carbohydrate ligand of anti-Gal. Studied α-gal nanoparticles were comprised of glycolipids with α-gal epitopes, phospholipids, and cholesterol. Binding of anti-Gal to α-gal nanoparticles in wounds activates the complement cascade, resulting in formation of chemotactic complement cleavage peptides that induce rapid recruitment of many macrophages. The Fc/Fcγ receptors interaction between anti-Gal coating α-gal nanoparticles and the recruited macrophages activates macrophages to produce cytokines/growth factors that promote wound healing and recruit stem cells. Studies of wound healing by α-gal nanoparticles were feasible in α1,3galactosyltransferase knockout mice and pigs. In contrast to other nonprimate mammals, these mice and pigs lack the α-gal epitope, and thus they are not immunotolerant to it and produce anti-Gal. Treatment of skin wounds and burns with α-gal nanoparticles resulted in 40-60% decrease in healing time in comparison with control wounds treated with saline. This accelerated healing is associated with increased recruitment of macrophages and extensive angiogenesis in wounds, faster regrowth of epidermis, and regeneration of the dermis. The accelerated healing further decreases and may completely eliminate fibrosis and scar formation in wounds. Since healing of internal injuries is mediated by mechanisms similar to those in external wound healing, it is suggested that α-gal nanoparticles treatment may also improve regeneration and restoration of biological function following internal injuries such as surgical incisions, myocardial ischemia following infarction, and nerve injuries.

  13. Metaphors for the Nature of Human-Computer Interaction in an Empowering Environment: Interaction Style Influences the Manner of Human Accomplishment.

    ERIC Educational Resources Information Center

    Weller, Herman G.; Hartson, H. Rex

    1992-01-01

    Describes human-computer interface needs for empowering environments in computer usage in which the machine handles the routine mechanics of problem solving while the user concentrates on its higher order meanings. A closed-loop model of interaction is described, interface as illusion is discussed, and metaphors for human-computer interaction are…

  14. The lethic phallus: rethinking the misery of Oedipus.

    PubMed

    Schmidt-Hellerau, Cordelia

    2008-07-01

    The author rethinks Sophocles' dramas Oedipus the King and Oedipus at Colonus with a special focus on how self- and object-preservative drives are expressed in the protagonist's thoughts, feelings, and actions. What endangered Oedipus' survival at the beginning of his life-the planned infanticide-becomes the disease that later befalls his kingdom and finally culminates in his self-mutilation, which entitles the blinded Oedipus to be cared for by Antigone until he dies. The concept of the lethic phallus demonstrates how trauma and the resultant failure in structuring the lethic energies of the preservative and death drives can result in a specific pathology in which disease is used as a trophy and a means to bind the object in an ongoing caretaker relationship.

  15. Collective curriculum design as a tool for rethinking scientific literacy

    NASA Astrophysics Data System (ADS)

    Plakitsi, Katerina

    2010-09-01

    This is a review essay from an educator's point of view, on the article written by Maria Inês Mafra Goulart and Wolff-Michael Roth Engaging young children in collective curriculum design. The article as well as the commentary essay contributes to the current agenda about the feasibility of social practices in (science) education even from the early childhood. A child centered collective curriculum design can be a tool for rethinking scientific literacy towards a multi-science perspective, participative thinking and dialectical teaching strategies that take account of structure or/and agency relationships. The review is structured on five levels: (a) scientific literacy, (b) multi-science perspective, (c) participative thinking—structure or∣and agency, (d) comments on methodology—the emergency of a new order, (e) conclusions.

  16. Investigation of the interaction modes between nonpolar organic pollutants with ionizable functional groups and natural organic matter via AuNP-based colorimetric assays.

    PubMed

    Niu, Hongyun; Wang, Saihua; Tan, Yixin; Cai, Yaqi

    2015-12-14

    For the first time, natural organic matter (NOM) modified AuNPs have been used as sensors to "observe" the specific interactions (such as hydrogen-bonds and halogen-bonds) between functional groups of organic compounds and NOM using colorimetric assays.

  17. "Big Loud Voice. You Have Important Things to Say": The Nature of Student Initiations during One Teacher's Interactive Read-Alouds

    ERIC Educational Resources Information Center

    Maloch, Beth; Beutel, Denise Duncan

    2010-01-01

    This qualitative study explored the nature of student initiations during interactive read alouds of fiction and non-fiction texts in a second grade, urban classroom. Data sources--including expanded field notes, video/audiotape records and transcripts, and teacher interviews--were analyzed inductively, utilizing the constant comparative method and…

  18. Natural language query system design for interactive information storage and retrieval systems. Presentation visuals. M.S. Thesis Final Report, 1 Jul. 1985 - 31 Dec. 1987

    NASA Technical Reports Server (NTRS)

    Dominick, Wayne D. (Editor); Liu, I-Hsiung

    1985-01-01

    This Working Paper Series entry represents a collection of presentation visuals associated with the companion report entitled Natural Language Query System Design for Interactive Information Storage and Retrieval Systems, USL/DBMS NASA/RECON Working Paper Series report number DBMS.NASA/RECON-17.

  19. Toward a Rethinking of the Relativity Revolution

    NASA Astrophysics Data System (ADS)

    Siegel, Daniel

    2014-03-01

    This journey in the history of physics is offered in celebration of David Cassidy's Pais Prize. The journey, undertaken in part with the community of historians of physics and in part not, starts from a conventional characterization of the relativity revolution as an abrupt transition, in 1905, from pre-Einsteinian darkness to Einsteinian light, and ends with an alternative perspective on the relativity revolution, seeing it as a process extending over 50 years, in two phases: first, the protorelativity phase, lasting from the early 1880s to 1905, and involving initial treatments of the length contraction, the mass increase, and invariance properties; second, the Einsteinian phase, beginning with his recasting of the basic theoretical framework--with the inclusion now of the time dilation and the E = mc2 relationship--and continuing with the ensuing competition between the protorelativistic and Einsteinian approaches, issuing in the final triumph of the Einsteinian approach only in the early 1930s. A proper appreciation of the character and importance of the protorelativity phase of the relativity revolution is relevant to a variety of contexts: for the teaching of relativity theory, it makes available a more concrete and pictorial approach to the relativistic effects--retaining greater (length contraction) or somewhat lesser (mass increase) validity to the present day; for the ongoing discourse on the nature of scientific revolutions, it provides a perspective on the intricacies and complexities of those occurrences, and on the elements of continuity and gradualism in even the most radical changes; and for our general understanding of historical process in the history of the sciences, it shows the importance of the broader scientific research community for even the most individual accomplishments.

  20. Rethinking Process-Based Writing Approaches in the ESOL Middle School Classroom: Developing Linguistic Fluency via Hybrid Pedagogies

    ERIC Educational Resources Information Center

    Pandey, Anjali

    2012-01-01

    This article calls for a rethinking of pure process-based approaches in the teaching of second language writers in the middle school classroom. The author provides evidence from a detailed case study of the writing of a Korean middle school student in a U.S. school setting to make a case for rethinking the efficacy of classic process-based…

  1. Natural variation in the heparan sulfate binding domain of the eastern equine encephalitis virus E2 glycoprotein alters interactions with cell surfaces and virulence in mice.

    PubMed

    Gardner, Christina L; Choi-Nurvitadhi, Jo; Sun, Chengqun; Bayer, Avraham; Hritz, Jozef; Ryman, Kate D; Klimstra, William B

    2013-08-01

    Recently, we compared amino acid sequences of the E2 glycoprotein of natural North American eastern equine encephalitis virus (NA-EEEV) isolates and demonstrated that naturally circulating viruses interact with heparan sulfate (HS) and that this interaction contributes to the extreme neurovirulence of EEEV (C. L. Gardner, G. D. Ebel, K. D. Ryman, and W. B. Klimstra, Proc. Natl. Acad. Sci. U. S. A., 108:16026-16031, 2011). In the current study, we have examined the contribution to HS binding of each of three lysine residues in the E2 71-to-77 region that comprise the primary HS binding site of wild-type (WT) NA-EEEV viruses. We also report that the original sequence comparison identified five virus isolates, each with one of three amino acid differences in the E2 71-to-77 region, including mutations in residues critical for HS binding by the WT virus. The natural variant viruses, which possessed either a mutation from lysine to glutamine at E2 71, a mutation from lysine to threonine at E2 71, or a mutation from threonine to lysine at E2 72, exhibited altered interactions with heparan sulfate and cell surfaces and altered virulence in a mouse model of EEEV disease. An electrostatic map of the EEEV E1/E2 heterotrimer based upon the recent Chikungunya virus crystal structure (J. E. Voss, M. C. Vaney, S. Duquerroy, C. Vonrhein, C. Girard-Blanc, E. Crublet, A. Thompson, G. Bricogne, and F. A. Rey, Nature, 468:709-712, 2010) showed the HS binding site to be at the apical surface of E2, with variants affecting the electrochemical nature of the binding site. Together, these results suggest that natural variation in the EEEV HS binding domain may arise during EEEV sylvatic cycles and that this variation may influence receptor interaction and the severity of EEEV disease.

  2. Linear Four-Chalcogen Interactions in Radical Cationic and Dicationic Dimers of 1,5-(Dichalcogena)canes: Nature of the Interactions Elucidated by QTAIM Dual Functional Analysis with QC Calculations.

    PubMed

    Hayashi, Satoko; Nagata, Kengo; Otsuki, Shota; Nakanishi, Waro

    2017-03-15

    The dynamic and static nature of extended hypervalent interactions of the (B)E···(A)E···(A)E···(B)E type are elucidated for four center-seven electron interactions (4c-7e) in the radical cationic dimers (1·(+)) and 4c-6e in the dicationic dimers (1(2+)) of 1,5-(dichalcogena)canes (2: (A)E(CH2CH2CH2)2(B)E: (A)E, (B)E = S, Se, Te, and O). The quantum theory of atoms-in-molecules dual functional analysis (QTAIM-DFA) is applied for the analysis. Total electron energy densities Hb(rc) are plotted versus Hb(rc) - Vb(rc)/2 [= (ℏ(2)/8m)∇(2)ρb(rc)] at bond critical points (BCPs) of the interactions, where Vb(rc) values show potential energy densities at BCPs. Data from the fully optimized structures correspond to the static nature of the interactions. Those from the perturbed structures around the fully optimized ones are also plotted, in addition to those of the fully optimized ones, which represent the dynamic nature of interactions. The (B)E···(A)E-(A)E···(B)E interactions in 1(2+) are stronger than the corresponding ones in 1·(+), respectively. On the one hand, for 1(2+) with (A)E, (B)E = S, Se, and Te, (A)E···(A)E are all classified by the shared shell interactions and predicted to have the weak covalent nature, except for those in 1a(2+) ((A)E = (B)E = S) and 1d(2+) ((A)E = (B)E = Se), which have the nature of regular closed shell (r-CS)/trigonal bipyramidal adduct formation through charge transfer (CT-TBP). On the other hand, (A)E···(B)E are predicted to have the nature of r-CS/molecular complex formation through charge transfer for 1a(2+), 1b(2+) ((A)E = Se; (B)E = S), and 1d(2+) or r-CS/CT-TBP for 1c(2+) ((A)E = Te; (B)E = S), 1e(2+) ((A)E = Te; (B)E = Se), and 1f(2+) ((A)E = (B)E = Te). The (B)E···(A)E-(A)E···(B)E interactions in 1·(+) and 1(2+) are well-analyzed by applying QTAIM-DFA.

  3. Interactions Between Fe(III)-oxides and Fe(III)-phyllosilicates During Microbial Reduction 2: Natural Subsurface Sediments

    SciTech Connect

    Wu, T.; Griffin, A. M.; Gorski, C. A.; Shelobolina, E. S.; Xu, H.; Kukkadapu, R. K.; Roden, E. E.

    2016-04-19

    Dissimilatory microbial reduction of solid-phase Fe(III)-oxides and Fe(III)-bearing phyllosilicates (Fe(III)-phyllosilicates) is an important process in anoxic soils, sediments, and subsurface materials. Although various studies have documented the relative extent of microbial reduction of single-phase Fe(III)-oxides and Fe(III)-phyllosilicates, detailed information is not available on interaction between these two processes in situations where both phases are available for microbial reduction. The goal of this research was to use the model dissimilatory iron-reducing bacterium (DIRB) Geobacter sulfurreducens to study Fe(III)-oxide vs. Fe(III)-phyllosilicate reduction in a range of subsurface materials and Fe(III)-oxide stripped versions of the materials. Low temperature (12K) Mossbauer spectroscopy was used to infer changes in the relative abundances of Fe(III)-oxide, Fe(III)-phyllosilicate, and phyllosilicate-associated Fe(II) (Fe(II)-phyllosilicate). A Fe partitioning model was employed to analyze the fate of Fe(II) and assess the potential for abiotic Fe(II)-catalyzed reduction of Fe(III)-phyllosilicates. The results showed that in most cases Fe(III)- oxide utilization dominated (70-100 %) bulk Fe(III) reduction activity, and that electron transfer from oxide-derived Fe(II) played only a minor role (ca. 10-20 %) in Fe partitioning. In addition, the extent of Fe(III)-oxide reduction was positively correlated to surface area-normalized cation exchange capacity and the phyllosilicate-Fe(III)/total Fe(III) ratio, which suggests that the phyllosilicates in the natural sediments promoted Fe(III)-oxide reduction by binding of oxide-derived Fe(II), thereby enhancing Fe(III)-oxide reduction by reducing or delaying the inhibitory effect that Fe(II) accumulation on oxide and DIRB cell surfaces has on Fe(III)-oxide reduction. In general our results suggest that although Fe(III)-oxide reduction is likely to dominate bulk Fe(III) reduction in most subsurface sediments, Fe

  4. Nature of interactions of tryptophan with zinc oxide nanoparticles and L-aspartic acid: A spectroscopic approach

    NASA Astrophysics Data System (ADS)

    Mandal, Gopa; Bhattacharya, Sudeshna; Ganguly, Tapan

    2009-04-01

    The interaction between an essential amino acid L-tryptophan (TRP) with semiconductor zinc oxide (ZnO) nanoparticles and amino acid L-aspartic acid (ASP) is investigated by steady state and time resolved spectroscopic techniques. In both the cases static mode of fluorescence quenching occurs indicating the formation of ground-state complex. Binding constants and the number of binding sites were determined for both the complexes. The observed thermodynamic parameters suggest that the key interacting forces involved are van der Waals interaction and hydrogen bonding in case of TRP and ZnO nanoparticles whereas hydrophobic interaction is responsible in formations of TRP-ASP complex.

  5. High-Affinity Small-Molecule Inhibitors of the Menin-Mixed Lineage Leukemia (MLL) Interaction Closely Mimic a Natural Protein-Protein Interaction

    SciTech Connect

    He, Shihan; Senter, Timothy J.; Pollock, Jonathan; Han, Changho; Upadhyay, Sunil Kumar; Purohit, Trupta; Gogliotti, Rocco D.; Lindsley, Craig W.; Cierpicki, Tomasz; Stauffer, Shaun R.; Grembecka, Jolanta

    2014-10-02

    The protein–protein interaction (PPI) between menin and mixed lineage leukemia (MLL) plays a critical role in acute leukemias, and inhibition of this interaction represents a new potential therapeutic strategy for MLL leukemias. We report development of a novel class of small-molecule inhibitors of the menin–MLL interaction, the hydroxy- and aminomethylpiperidine compounds, which originated from HTS of ~288000 small molecules. We determined menin–inhibitor co-crystal structures and found that these compounds closely mimic all key interactions of MLL with menin. Extensive crystallography studies combined with structure-based design were applied for optimization of these compounds, resulting in MIV-6R, which inhibits the menin–MLL interaction with IC50 = 56 nM. Treatment with MIV-6 demonstrated strong and selective effects in MLL leukemia cells, validating specific mechanism of action. Our studies provide novel and attractive scaffold as a new potential therapeutic approach for MLL leukemias and demonstrate an example of PPI amenable to inhibition by small molecules.

  6. The Genetics Underlying Natural Variation in the Biotic Interactions of Arabidopsis thaliana: The Challenges of Linking Evolutionary Genetics and Community Ecology.

    PubMed

    Roux, F; Bergelson, J

    2016-01-01

    In the context of global change, predicting the responses of plant communities in an ever-changing biotic environment calls for a multipronged approach at the interface of evolutionary genetics and community ecology. However, our understanding of the genetic basis of natural variation involved in mediating biotic interactions, and associated adaptive dynamics of focal plants in their natural communities, is still in its infancy. Here, we review the genetic and molecular bases of natural variation in the response to biotic interactions (viruses, bacteria, fungi, oomycetes, herbivores, and plants) in the model plant Arabidopsis thaliana as well as the adaptive value of these bases. Among the 60 identified genes are a number that encode nucleotide-binding site leucine-rich repeat (NBS-LRR)-type proteins, consistent with early examples of plant defense genes. However, recent studies have revealed an extensive diversity in the molecular mechanisms of defense. Many types of genetic variants associate with phenotypic variation in biotic interactions, even among the genes of large effect that tend to be identified. In general, we found that (i) balancing selection rather than directional selection explains the observed patterns of genetic diversity within A. thaliana and (ii) the cost/benefit tradeoffs of adaptive alleles can be strongly dependent on both genomic and environmental contexts. Finally, because A. thaliana rarely interacts with only one biotic partner in nature, we highlight the benefit of exploring diffuse biotic interactions rather than tightly associated host-enemy pairs. This challenge would help to improve our understanding of coevolutionary quantitative genetics within the context of realistic community complexity.

  7. Interactions between Drosophila and its natural yeast symbionts-Is Saccharomyces cerevisiae a good model for studying the fly-yeast relationship?

    PubMed

    Hoang, Don; Kopp, Artyom; Chandler, James Angus

    2015-01-01

    Yeasts play an important role in the biology of the fruit fly, Drosophila melanogaster. In addition to being a valuable source of nutrition, yeasts affect D. melanogaster behavior and interact with the host immune system. Most experiments investigating the role of yeasts in D. melanogaster biology use the baker's yeast, Saccharomyces cerevisiae. However, S. cerevisiae is rarely found with natural populations of D. melanogaster or other Drosophila species. Moreover, the strain of S. cerevisiae used most often in D. melanogaster experiments is a commercially and industrially important strain that, to the best of our knowledge, was not isolated from flies. Since disrupting natural host-microbe interactions can have profound effects on host biology, the results from D. melanogaster-S. cerevisiae laboratory experiments may not be fully representative of host-microbe interactions in nature. In this study, we explore the D. melanogaster-yeast relationship using five different strains of yeast that were isolated from wild Drosophila populations. Ingested live yeasts have variable persistence in the D. melanogaster gastrointestinal tract. For example, Hanseniaspora occidentalis persists relative to S. cerevisiae, while Brettanomyces naardenensis is removed. Despite these differences in persistence relative to S. cerevisiae, we find that all yeasts decrease in total abundance over time. Reactive oxygen species (ROS) are an important component of the D. melanogaster anti-microbial response and can inhibit S. cerevisiae growth in the intestine. To determine if sensitivity to ROS explains the differences in yeast persistence, we measured yeast growth in the presence and absence of hydrogen peroxide. We find that B. naardenesis is completely inhibited by hydrogen peroxide, while H. occidentalis is not, which is consistent with yeast sensitivity to ROS affecting persistence within the D. melanogaster gastrointestinal tract. We also compared the feeding preference of D

  8. The Dynamic Nature of Goals and Message Production as Revealed in a Sequential Analysis of Conflict Interactions

    ERIC Educational Resources Information Center

    Keck, K. Laura; Samp, Jennifer A.

    2007-01-01

    Although message-production theories often assume that goals behave dynamically to direct communication behavior, few studies consider the interconnectedness of goals and behavior throughout interactions. Here, the interrelationship of communication goals and tactics was examined through a sequential analysis of 47 conflict interactions between…

  9. Noncovalent π⋅⋅⋅π interaction between graphene and aromatic molecule: structure, energy, and nature.

    PubMed

    Wang, Weizhou; Zhang, Yu; Wang, Yi-Bo

    2014-03-07

    Noncovalent π⋅⋅⋅π interactions between graphene and aromatic molecules have been studied by using density functional theory with empirical dispersion correction (ωB97X-D) combined with zeroth-order symmetry adapted perturbation theory (SAPT0). Excellent agreement of the interaction energies computed by means of ωB97X-D and spin component scaled (SCS) SAPT0 methods, respectively, shows great promise for the two methods in the study of the adsorption of aromatic molecules on graphene. The other important finding in this study is that, according to SCS-SAPT0 analyses, π⋅⋅⋅π interactions between graphene and aromatic molecules are largely dependent on both dispersion and electrostatic type interactions. It is also noticed that π⋅⋅⋅π interactions become stronger and more dispersive (less electrostatic) upon substitution of the very electronegative fluorine atoms onto the aromatic molecules.

  10. Noncovalent π⋅⋅⋅π interaction between graphene and aromatic molecule: Structure, energy, and nature

    SciTech Connect

    Wang, Weizhou E-mail: ybw@gzu.edu.cn; Zhang, Yu; Wang, Yi-Bo E-mail: ybw@gzu.edu.cn

    2014-03-07

    Noncovalent π⋅⋅⋅π interactions between graphene and aromatic molecules have been studied by using density functional theory with empirical dispersion correction (ωB97X-D) combined with zeroth-order symmetry adapted perturbation theory (SAPT0). Excellent agreement of the interaction energies computed by means of ωB97X-D and spin component scaled (SCS) SAPT0 methods, respectively, shows great promise for the two methods in the study of the adsorption of aromatic molecules on graphene. The other important finding in this study is that, according to SCS-SAPT0 analyses, π⋅⋅⋅π interactions between graphene and aromatic molecules are largely dependent on both dispersion and electrostatic type interactions. It is also noticed that π⋅⋅⋅π interactions become stronger and more dispersive (less electrostatic) upon substitution of the very electronegative fluorine atoms onto the aromatic molecules.

  11. The Nature of Metal-Metal Interactions in Dimeric Hydrides and Halides of Group 11 Elements in the Light of High Level Relativistic Calculations.

    PubMed

    Dem'yanov, Piotr I; Polestshuk, Pavel M; Kostin, Vladimir V

    2017-03-08

    The titular calculations show that charges at metal atoms M are apparently the main factor governing the nature of M⋅⋅⋅M interactions in two-nuclear coinage-metal complexes, and there are certain critical values of positive charges on M atoms, on exceeding which the pair-wise M⋅⋅⋅M interactions and/or the binding between M atoms in such complexes become repulsive despite negative formation energies of such complexes, short M-M internuclear distances, and the existence of a bond critical point (BCP) between M atoms.

  12. Hydrothermal vents and methane seeps: Rethinking the sphere of influence

    USGS Publications Warehouse

    Levin, Lisa A.; Baco, Amy; Bowden, David; Colaco, Ana; Cordes, Erik E.; Cunha, Marina; Demopoulos, Amanda; Gobin, Judith; Grupe, Ben; Le, Jennifer; Metaxas, Anna; Netburn, Amanda; Rouse, Greg; Thurber, Andrew; Tunnicliffe, Verena; Van Dover, Cindy L.; Vanreusel, Ann; Watling, Les

    2016-01-01

    Although initially viewed as oases within a barren deep ocean, hydrothermal vent and methane seep communities are now recognized to interact with surrounding ecosystems on the sea floor and in the water column, and to affect global geochemical cycles. The importance of understanding these interactions is growing as the potential rises for disturbance from oil and gas extraction, seabed mining and bottom trawling. Here we synthesize current knowledge of the nature, extent and time and space scales of vent and seep interactions with background systems. We document an expanded footprint beyond the site of local venting or seepage with respect to elemental cycling and energy flux, habitat use, trophic interactions, and connectivity. Heat and energy are released, global biogeochemical and elemental cycles are modified, and particulates are transported widely in plumes. Hard and biotic substrates produced at vents and seeps are used by “benthic background” fauna for attachment substrata, shelter, and access to food via grazing or through position in the current, while particulates and fluid fluxes modify planktonic microbial communities. Chemosynthetic production provides nutrition to a host of benthic and planktonic heterotrophic background species through multiple horizontal and vertical transfer pathways assisted by flow, gamete release, animal movements, and succession, but these pathways remain poorly known. Shared species, genera and families indicate that ecological and evolutionary connectivity exists among vents, seeps, organic falls and background communities in the deep sea; the genetic linkages with inactive vents and seeps and background assemblages however, are practically unstudied. The waning of venting or seepage activity generates major transitions in space and time that create links to surrounding ecosystems, often with identifiable ecotones or successional stages. The nature of all these interactions is dependent on water depth, as well as

  13. Influence of substituents on the nature of metal⋯π interaction and its cooperativity with halogen bond

    SciTech Connect

    Gao, Meng; Cheng, Jianbo E-mail: liqingzhong1990@sina.com; Yang, Xin; Li, Wenzuo; Xiao, Bo; Li, Qingzhong E-mail: liqingzhong1990@sina.com

    2015-08-07

    High-level quantum chemical calculations have been performed to investigate the influence of substituents on the metal—π interaction and its cooperative effect with halogen bond in C{sub 2}X{sub 4}⋯MCN⋯ClF (X = H, CN, CH{sub 3}; M = Cu, Ag, Au). The strong electron-withdrawing group CN weakens the metal—π covalent interaction, while the weak electron-withdrawing group CH{sub 3} strengthens it. The metal—π covalent interaction is dominated by electrostatic energy although the AuCN complex has approximately equal electrostatic and polarization contributions. However, the metal—π covalent interaction is governed by polarization energy due to the CN substitution. A cooperative effect is found for the halogen bond and metal—π interactions in C{sub 2}H{sub 4}⋯MCN⋯ClF, while a diminutive effect occurs in the triads by the CN substituent. Orbital interaction analysis indicates that the strong electron-withdrawing group CN causes the C=C group vary from a stronger donor orbital to a stronger acceptor orbital.

  14. U.S. Support of Plan Colombia: Rethinking the Ends and Means

    DTIC Science & Technology

    2001-05-01

    national security. Dr. Flynn argues that the U.S. emphasis on drug control in its support of Plan Colombia is misguided and akin to prescribing an...U.S. SUPPORT OF PLAN COLOMBIA: RETHINKING THE ENDS AND MEANS Stephen E. Flynn May 2001 Form SF298 Citation Data Report Date ("DD MON YYYY...34) 00MAY2001 Report Type N/A Dates Covered (from... to) ("DD MON YYYY") Title and Subtitle U.S. SUPPORT OF PLAN COLOMBIA: RETHINKING THE ENDS AND MEANS

  15. A natural orbital analysis of the long range behavior of chemical bonding and van der Waals interaction in singlet H2: the issue of zero natural orbital occupation numbers.

    PubMed

    Sheng, X W; Mentel, Ł M; Gritsenko, O V; Baerends, E J

    2013-04-28

    This paper gives a natural orbital (NO) based analysis of the van der Waals interaction in (singlet) H2 at long distance. The van der Waals interaction, even if not leading to a distinct van der Waals well, affects the shape of the interaction potential in the van der Waals distance range of 5-9 bohrs and can be clearly distinguished from chemical bonding effects. In the NO basis the van der Waals interaction can be quantitatively covered with, apart from the ground state configurations (1σ(g))(2) and (1σ(u))(2), just the 4 configurations (2σ(g))(2) and (2σ(u))(2), and (1π(u))(2) and (1π(g))(2). The physics of the dispersion interaction requires and explains the peculiar relatively large positive CI coefficients of the doubly excited electron configurations (2σ(u))(2) and (1π(g))(2) (the occupancy amplitudes of the 2σ(u) and 1π(gx, y) NOs) in the distance range 5-9 bohrs, which have been observed before by Cioslowski and Pernal [Chem. Phys. Lett. 430, 188 (2006)]. We show that such positive occupancy amplitudes do not necessarily lead to the existence of zero occupation numbers at some H-H distances.

  16. Pharmaceuticals May Disrupt Natural Chemical Information Flows and Species Interactions in Aquatic Systems: Ideas and Perspectives on a Hidden Global Change.

    PubMed

    Van Donk, Ellen; Peacor, Scott; Grosser, Katharina; De Senerpont Domis, Lisette N; Lürling, Miquel

    Pharmaceuticals consumption by humans and animals is increasing substantially, leading to unprecedented levels of these compounds in aquatic environments worldwide. Recent findings that concentrations reach levels that can directly have negative effects on organisms are important per se, but also sound an alarm for other potentially more pervasive effects that arise from the interconnected nature of ecological communities. Aquatic organisms use chemical cues to navigate numerous challenges, including the location of mates and food, and the avoidance of natural enemies. Low concentrations of pharmaceuticals can disrupt this "smellscape" of information leading to maladaptive responses. Furthermore, direct effects of pharmaceuticals on the traits and abundance of one species can cascade through a community, indirectly affecting other species. We review mechanisms by which pharmaceuticals in surface waters can disrupt natural chemical information flows and species interactions. Pharmaceuticals form a new class of chemical threats, which could have far-reaching implications for ecosystem functioning and conservation management.

  17. Revealing the neural networks associated with processing of natural social interaction and the related effects of actor-orientation and face-visibility.

    PubMed

    Saggar, Manish; Shelly, Elizabeth Walter; Lepage, Jean-Francois; Hoeft, Fumiko; Reiss, Allan L

    2014-01-01

    Understanding the intentions and desires of those around us is vital for adapting to a dynamic social environment. In this paper, a novel event-related functional Magnetic Resonance Imaging (fMRI) paradigm with dynamic and natural stimuli (2s video clips) was developed to directly examine the neural networks associated with processing of gestures with social intent as compared to nonsocial intent. When comparing social to nonsocial gestures, increased activation in both the mentalizing (or theory of mind) and amygdala networks was found. As a secondary aim, a factor of actor-orientation was included in the paradigm to examine how the neural mechanisms differ with respect to personal engagement during a social interaction versus passively observing an interaction. Activity in the lateral occipital cortex and precentral gyrus was found sensitive to actor-orientation during social interactions. Lastly, by manipulating face-visibility we tested whether facial information alone is the primary driver of neural activation differences observed between social and nonsocial gestures. We discovered that activity in the posterior superior temporal sulcus (pSTS) and fusiform gyrus (FFG) was partially driven by observing facial expressions during social gestures. Altogether, using multiple factors associated with processing of natural social interaction, we conceptually advance our understanding of how social stimuli is processed in the brain and discuss the application of this paradigm to clinical populations where atypical social cognition is manifested as a key symptom.

  18. A Lot Can Happen in a Few Minutes: Examining Dynamic Patterns Within an Interaction to Illuminate the Interpersonal Nature of Personality Disorders.

    PubMed

    Sadler, Pamela; Woody, Erik; McDonald, Kelly; Lizdek, Ivana; Little, Jerrica

    2015-08-01

    Although problematic interpersonal tendencies have often been characterized as a traitlike excess of a particular interpersonal style, the interpersonal nature of personality disorders may have more to do with patterns of variability in interpersonal behavior and the relation of this variability to the varying behavior of interaction partners. Indeed, problematic interpersonal tendencies may often be evident as patterns within even one interaction. A useful methodology for examining moment-to-moment patterns within the course of an interaction is the computer joystick technique. To illustrate the potential of this new approach for studying problematic interpersonal patterns, the authors provide joystick-based analyses of the videoed session between Dr. Donald Meichenbaum and the client, Richard (Shostrom, 1986a). The authors show how to examine the association between concurrent levels of dominance and affiliation within a person, patterns of covariation between partners, and the moderation of such entrainment patterns. They also discuss how these indices could illuminate disordered interpersonal patterns.

  19. A Lettuce (Lactuca sativa) Homolog of Human Nogo-B Receptor Interacts with cis-Prenyltransferase and Is Necessary for Natural Rubber Biosynthesis*

    PubMed Central

    Qu, Yang; Chakrabarty, Romit; Tran, Hue T.; Kwon, Eun-Joo G.; Kwon, Moonhyuk; Nguyen, Trinh-Don; Ro, Dae-Kyun

    2015-01-01

    Natural rubber (cis-1,4-polyisoprene) is an indispensable biopolymer used to manufacture diverse consumer products. Although a major source of natural rubber is the rubber tree (Hevea brasiliensis), lettuce (Lactuca sativa) is also known to synthesize natural rubber. Here, we report that an unusual cis-prenyltransferase-like 2 (CPTL2) that lacks the conserved motifs of conventional cis-prenyltransferase is required for natural rubber biosynthesis in lettuce. CPTL2, identified from the lettuce rubber particle proteome, displays homology to a human NogoB receptor and is predominantly expressed in latex. Multiple transgenic lettuces expressing CPTL2-RNAi constructs showed that a decrease of CPTL2 transcripts (3–15% CPTL2 expression relative to controls) coincided with the reduction of natural rubber as low as 5%. We also identified a conventional cis-prenyltransferase 3 (CPT3), exclusively expressed in latex. In subcellular localization studies using fluorescent proteins, cytosolic CPT3 was relocalized to endoplasmic reticulum by co-occurrence of CPTL2 in tobacco and yeast at the log phase. Furthermore, yeast two-hybrid data showed that CPTL2 and CPT3 interact. Yeast microsomes containing CPTL2/CPT3 showed enhanced synthesis of short cis-polyisoprenes, but natural rubber could not be synthesized in vitro. Intriguingly, a homologous pair CPTL1/CPT1, which displays ubiquitous expressions in lettuce, showed a potent dolichol biosynthetic activity in vitro. Taken together, our data suggest that CPTL2 is a scaffolding protein that tethers CPT3 on endoplasmic reticulum and is necessary for natural rubber biosynthesis in planta, but yeast-expressed CPTL2 and CPT3 alone could not synthesize high molecular weight natural rubber in vitro. PMID:25477521

  20. A lettuce (Lactuca sativa) homolog of human Nogo-B receptor interacts with cis-prenyltransferase and is necessary for natural rubber biosynthesis.

    PubMed

    Qu, Yang; Chakrabarty, Romit; Tran, Hue T; Kwon, Eun-Joo G; Kwon, Moonhyuk; Nguyen, Trinh-Don; Ro, Dae-Kyun

    2015-01-23

    Natural rubber (cis-1,4-polyisoprene) is an indispensable biopolymer used to manufacture diverse consumer products. Although a major source of natural rubber is the rubber tree (Hevea brasiliensis), lettuce (Lactuca sativa) is also known to synthesize natural rubber. Here, we report that an unusual cis-prenyltransferase-like 2 (CPTL2) that lacks the conserved motifs of conventional cis-prenyltransferase is required for natural rubber biosynthesis in lettuce. CPTL2, identified from the lettuce rubber particle proteome, displays homology to a human NogoB receptor and is predominantly expressed in latex. Multiple transgenic lettuces expressing CPTL2-RNAi constructs showed that a decrease of CPTL2 transcripts (3-15% CPTL2 expression relative to controls) coincided with the reduction of natural rubber as low as 5%. We also identified a conventional cis-prenyltransferase 3 (CPT3), exclusively expressed in latex. In subcellular localization studies using fluorescent proteins, cytosolic CPT3 was relocalized to endoplasmic reticulum by co-occurrence of CPTL2 in tobacco and yeast at the log phase. Furthermore, yeast two-hybrid data showed that CPTL2 and CPT3 interact. Yeast microsomes containing CPTL2/CPT3 showed enhanced synthesis of short cis-polyisoprenes, but natural rubber could not be synthesized in vitro. Intriguingly, a homologous pair CPTL1/CPT1, which displays ubiquitous expressions in lettuce, showed a potent dolichol biosynthetic activity in vitro. Taken together, our data suggest that CPTL2 is a scaffolding protein that tethers CPT3 on endoplasmic reticulum and is necessary for natural rubber biosynthesis in planta, but yeast-expressed CPTL2 and CPT3 alone could not synthesize high molecular weight natural rubber in vitro.

  1. Rethink, Reform, Reenter: An Entrepreneurial Approach to Prison Programming.

    PubMed

    Keena, Linda; Simmons, Chris

    2015-07-01

    The purpose of this article was to present a description and first-stage evaluation of the impact of the Ice House Entrepreneurship Program on the learning experience of participating prerelease inmates at a Mississippi maximum-security prison and their perception of the transfer of skills learned in program into securing employment upon reentry. The Ice House Entrepreneurship Program is a 12-week program facilitated by volunteer university professors to inmates in a prerelease unit of a maximum-security prison in Mississippi. Participants' perspectives were examined through content analysis of inmates' answers to program Reflection and Response Assignments and interviews. The analyses were conducted according to the constant comparative method. Findings reveal the emergent of eight life-lessons and suggest that this is a promising approach to prison programming for prerelease inmates. This study discusses three approaches to better prepare inmates for a mindset change. The rethink, reform, and reenter approaches help break the traditional cycle of release, reoffend, and return.

  2. HIV Exposed Infants: Rethinking care for a lifelong condition

    PubMed Central

    Sugandhi, N; Rodrigues, J; Kim, MH; Ahmed, S; Amzel, A; Tolle, M; Dzubien, E; Rivadeneira, E; Kellerman, S

    2014-01-01

    Summary Each year over a million infants are born to HIV infected mothers though with scale up of prevention of mother to child transmission (PMTCT) interventions, only 210,000 of the 1.3 million infants born to mothers with HIV/AIDS in 2012 became infected. Current programmatic efforts directed at infants born to HIV-infected mothers are primarily focused on decreasing their risk of infection, but this emphasis on maternal interventions has meant follow-up of exposed infants has been poor. Programs are struggling to retain this population in care until the end of exposure, typically at the cessation of breastfeeding, between 12 and 24 months of age. But HIV exposure is a life-long condition that continues to impact the health and well-being of a child long after exposure has ended. A better understanding of the impact of HIV on exposed infants is needed and new programs and interventions must take into consideration the long-term health needs of this growing population. The introduction of lifelong treatment for all HIV-infected pregnant women is an opportunity to rethink how we provide services adapted for the long-term retention of mother-infant pairs. PMID:24361628

  3. Particle size and particle-particle interactions on tensile properties and reinforcement of corn flour particles in natural rubber

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Renewable corn flour has a significant reinforcement effect in natural rubber. The corn flour was hydrolyzed and microfluidized to reduce its particle size. Greater than 90% of the hydrolyzed corn flour had an average size of ~300 nm, a reduction of 33 times compared to unhydrolyzed corn flour. Comp...

  4. Explicit-Reflective Teaching Nature of Science as Embedded within the Science Topic: Interactive Historical Vignettes Technique

    ERIC Educational Resources Information Center

    Nur, Erdogan Melek; Fitnat, Koseoglu

    2015-01-01

    It is obvious that more extensive work is needed in developing historical materials that address nature of science (NOS) concepts that will be implemented by teachers. Owing to the importance of meeting this need, research problem of this study is to design historical vignettes focused on the concept of chemical equilibrium which lies at the heart…

  5. On the nature of interactions in the F2 OXe(…) NCCH3 complex: Is there the Xe(IV)N bond?

    PubMed

    Makarewicz, Emilia; Lundell, Jan; Gordon, Agnieszka J; Berski, Slawomir

    2016-07-01

    Nature of the bonding in isolated XeOF2 molecule and F2 OXe(…) NCCH3 complexes have been studied in the gas phase (0 K) using Quantum Chemical Topology methods. The wave functions have been approximated at the MP2 and DFT levels of calculations, using the APFD, B3LYP, M062X, and B2PLYP functionals with the GD3 dispersion correction. The nature of the formal XeO bond in the XeOF2 monomer depends on the basis set used (all-electron vs. the ecp-28 approximation for Xe). Within the all-electron basis set approach the bond is represented by two bonding attractors, Vi = 1,2 (Xe,O), with total population of about 1.06e and highly delocalized electron density in both bonding basins. No bonding basins are observed using the ecp-28 approximation. These results shows that the nature of xenon-oxygen is complicated and may be described with mesomeric equilibrium of the Lewis representations: Xe((+)) O((-)) and Xe((-)) O((+)) . For both the xenon-oxygen and xenon-fluorine interactions the charge-shift model can be applied. The F2 OXe(…) NCCH3 complex exists in two structures: "parallel," stabilized by non-covalent C(…) O and Xe(…) N interactions and "linear" stabilized by the Xe(…) N interaction. Topological analysis of ELF shows that the F2 OXe(…) NCCH3 molecule appears as a weakly bound intermolecular complex. Intermolecular interaction energy components have also been studied using Symmetry Adapted Perturbation Theory. © 2016 Wiley Periodicals, Inc.

  6. Assessing the impact of natural service bulls and genotype by environment interactions on genetic gain and inbreeding in organic dairy cattle genomic breeding programs.

    PubMed

    Yin, T; Wensch-Dorendorf, M; Simianer, H; Swalve, H H; König, S

    2014-06-01

    The objective of the present study was to compare genetic gain and inbreeding coefficients of dairy cattle in organic breeding program designs by applying stochastic simulations. Evaluated breeding strategies were: (i) selecting bulls from conventional breeding programs, and taking into account genotype by environment (G×E) interactions, (ii) selecting genotyped bulls within the organic environment for artificial insemination (AI) programs and (iii) selecting genotyped natural service bulls within organic herds. The simulated conventional population comprised 148 800 cows from 2976 herds with an average herd size of 50 cows per herd, and 1200 cows were assigned to 60 organic herds. In a young bull program, selection criteria of young bulls in both production systems (conventional and organic) were either 'conventional' estimated breeding values (EBV) or genomic estimated breeding values (GEBV) for two traits with low (h 2=0.05) and moderate heritability (h 2=0.30). GEBV were calculated for different accuracies (r mg), and G×E interactions were considered by modifying originally simulated true breeding values in the range from r g=0.5 to 1.0. For both traits (h 2=0.05 and 0.30) and r mg⩾0.8, genomic selection of bulls directly in the organic population and using selected bulls via AI revealed higher genetic gain than selecting young bulls in the larger conventional population based on EBV; also without the existence of G×E interactions. Only for pronounced G×E interactions (r g=0.5), and for highly accurate GEBV for natural service bulls (r mg>0.9), results suggests the use of genotyped organic natural service bulls instead of implementing an AI program. Inbreeding coefficients of selected bulls and their offspring were generally lower when basing selection decisions for young bulls on GEBV compared with selection strategies based on pedigree indices.

  7. Coastal Resilience: Using interactive decision support to address the needs of natural and human communities in Long Island Sound, USA

    NASA Astrophysics Data System (ADS)

    Gilmer, B.; Whelchel, A.; Newkirk, S.; Beck, M.; Shepard, C.; Ferdana, Z.

    2010-12-01

    Coastal Resilience (www.coastalresilience.org) is an ecosystem-based, coastal and marine spatial planning framework and web mapping application that illustrates ecological, socioeconomic, and coastal hazards information in Long Island Sound (New York and Connecticut), USA. Much of Long Island Sound’s private property is only inches above sea level, placing millions of dollars in public and private funds at risk to rising sea levels and other coastal hazards. These impacts also threaten wetlands and other coastal ecosystems that provide habitat, natural buffers to storms, and other ecosystem services. Despite a growing awareness of global climate change, local decision makers still lack the tools to examine different management objectives as sea levels rise and coastal hazards increase. The Coastal Resilience project provides tools and information to better inform decision-making with a primary goal of identifying vulnerable human and natural communities, while illustrating the important role that ecosystems will play in the face of sea level rise and increased storm intensity. This study focuses on The Nature Conservancy’s use of innovative spatial analysis techniques and community engagement to identify and plan for the protection of vulnerable coastal communities and ecosystems, natural resource migration, and economic risk. This work is intended to help identify ecosystem based adaptation solutions in the face of global climate change. The Nature Conservancy, working with multiple partners such as the NASA Goddard Institute for Space Studies and NOAA’s Coastal Services Center, deliver this information via the internet to help local decision makers keep the environment and public safety in mind.

  8. Changes in Children's Peer Interactions Following a Natural Disaster: How Predisaster Bullying and Victimization Rates Changed Following Hurricane Katrina

    ERIC Educational Resources Information Center

    Terranova, Andrew M.; Boxer, Paul; Morris, Amanda Sheffield

    2009-01-01

    Youth exposed to disasters experience stress and adjustment difficulties, which likely influence their interactions with peers. In this study, we examined changes in bullying and peer victimization in two cohorts of children. Youth from an area affected by Hurricane Katrina were assessed pre- and postdisaster (n = 96, mean [M] = 10.9 years old,…

  9. Insights into the nature of fronto-temporal interactions from a biconditional discrimination task in the monkey.

    PubMed

    Easton, Alexander; Gaffan, David

    2002-10-17

    Previous work in monkeys has shown that both frontal and inferior temporal cortices are required to solve visual learning tasks. When communication between these cortical areas is prevented within the same hemisphere by crossed lesions of the frontal cortex in one hemisphere and the inferior temporal cortex in the opposite hemisphere, most learning tasks are impaired, but learning of object-reward associations is unimpaired. The current experiment aims to understand further the role of the interaction between the frontal and inferior temporal cortices in learning tasks. We trained monkeys on a biconditional discrimination task, in which different visual cues guided behaviour towards choice objects. One visual cue predicted immediate delivery of reward to a correct response, the other visual cue predicted a delayed delivery of reward to a correct response. Pre-operative behavioural data clearly shows that the monkeys form expectations of the reward outcome for the individual cues and choice objects. Crossed lesions of frontal and inferior temporal cortices, however, produce no impairment on this task. The result suggests (in combination with previous experiments) that task difficulty does not determine the reliance of a task on interactions between the frontal cortex and the inferior temporal cortex within the same hemisphere. Instead, we propose that tasks that can be solved by using expectation of the reward outcome do not require interaction of frontal and inferior temporal cortices within the same hemisphere. The results are discussed in the context of other data on frontal interactions with inferior temporal cortex in learning tasks.

  10. Interactions between natural killer cells and dendritic cells favour T helper1-type responses to BCG in calves.

    PubMed

    Hamilton, Carly A; Mahan, Suman; Entrican, Gary; Hope, Jayne C

    2016-08-17

    Vaccination of neonatal calves with BCG induces a significant level of protection from infection with Mycobacterium bovis, the causative agent of bovine tuberculosis. Since neonatal vaccination of humans with BCG induces activation of NK cells, and young calves have high circulating numbers of these cells, we hypothesised that NK cells are important in the protective response to BCG. Furthermore, since NK cells play a role in shaping adaptive immune responses through interactions with DCs, we investigated the interactions between NK cells and DCs in the context of BCG. DCs infected with BCG expressed significantly higher levels of MHC class II and the co-stimulatory molecules CD40 and CD80, alongside augmented production of the Th1 polarising cytokine IL-12, when compared with uninfected DCs. Following in vitro co-culture with BCG-infected DCs, NK cells increased their expression of the activatory molecule CD25, with preferential activation of the CD2- NK cell subset. NK cell effector function, as measured by production of IFN-γ, was also significantly enhanced following co-culture with BCG-infected DCs. This study provides novel evidence to demonstrate that NK cells phenotypically and functionally mature after interactions with DCs in the context of BCG. Furthermore, through the production of IFN-γ and IL-12 by NK cells and DCs respectively, this interaction may drive protective Th1-type immune responses to Mycobacteria.

  11. A Two-Mode Clustering Method to Capture the Nature of the Dominant Interaction Pattern in Large Profile Data Matrices

    ERIC Educational Resources Information Center

    Schepers, Jan; Van Mechelen, Iven

    2011-01-01

    Profile data abound in a broad range of research settings. Often it is of considerable theoretical importance to address specific structural questions with regard to the major pattern as included in such data. A key challenge in this regard pertains to identifying which type of interaction (double ordinal, mixed ordinal/disordinal, double…

  12. Probing the nature of interactions in SH2 binding interfaces--evidence from electrospray ionization mass spectrometry.

    PubMed Central

    Chung, E. W.; Henriques, D. A.; Renzoni, D.; Morton, C. J.; Mulhern, T. D.; Pitkeathly, M. C.; Ladbury, J. E.; Robinson, C. V.

    1999-01-01

    We have adopted nanoflow electrospray ionization mass spectrometry (ESI-MS) and isothermal titration calorimetry (ITC) to probe the mechanism of peptide recognition by the SH2 domain from the Src family tyrosine kinase protein, Fyn. This domain is involved in the mediation of intracellular signal transduction pathways by interaction with proteins containing phosphorylated tyrosine (Y*) residues. The binding of tyrosyl phosphopeptides can mimic these interactions. Specificity in these interactions has been attributed to the interaction of the Y* and residues proximal and C-terminal to it. Previous studies have established that for specific binding with Fyn, the recognition sequence consists of pTyr-Glu-Glu-Ile. The specific interactions involve the binding of Y* with the ionic, and the Y* + 3 Ile residue with the hydrophobic binding pockets on the surface of the Fyn SH2 domain. In this work, a variation in the Y* + 3 residue of this high-affinity sequence was observed to result in changes in the relative binding affinities as determined in solution (ITC) and in the gas phase (nanoflow ESI-MS). X-ray analysis shows that a feature of the Src family SH2 domains is the involvement of water molecules in the peptide binding site. Under the nanoflow ESI conditions, water molecules appear to be maintained in the Fyn SH2-ligand complex. Compelling evidence for these molecules being incorporated in the SH2-peptide interface is provided by the prevalence of the peaks assigned to water-bound over the water-free complex at high-energy conditions. Thus, the stability of water protein-ligand complex appears to be intimately linked to the presence of water. PMID:10548041

  13. Conformational analyses of bacillomycin D, a natural antimicrobial lipopeptide, alone or in interaction with lipid monolayers at the air-water interface.

    PubMed

    Nasir, Mehmet Nail; Besson, Françoise

    2012-12-01

    Bacillomycin D is a natural antimicrobial lipopeptide belonging to the iturin family. It is produced by Bacillus subtilis strains. Bacillomycin D is characterized by its strong antifungal and hemolytic properties, due to its interaction with the plasma membrane of sensitive cells. Until now, only few limited analyses were conducted to understand the biological activities of bacillomycin D at the molecular level. Our purpose was to analyze the conformation of bacillomycin D using IR spectroscopy and to model its interactions with cytoplasmic membranes using Langmuir interfacial monolayers. Our findings indicate that bacillomycin D contains turns and allow to model its three-dimensional structure. Bacillomycin D formed a monolayer film at the air-water interface and kept its turn conformation, as shown by polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). To identify the membrane lipid target of bacillomycin D, its interactions with pure lipid monolayers were analyzed and an original behavior of the lipopeptide toward cholesterol-containing monolayers was shown. This original behavior was lost when bacillomycin D was interacting with pure cholesteryl acetate monolayers, suggesting the involvement of the alcohol group of cholesterol in the lipopeptide-cholesterol interaction.

  14. Rethinking Adult Education for Development II. Conference Proceedings (Ljubljana, Slovenia, October 6-9, 1993).

    ERIC Educational Resources Information Center

    Svetina, Metka, Ed.

    This book contains papers, reports, and opening and closing speeches presented at a worldwide conference of adult education experts. The document begins with the following: an introduction (Jelenc); a reprinted article, "Time to Collectively Rethink Our Field" (Franklin W. Spikes); and opening speeches by various adult education officials (Jelenc,…

  15. Civic Education for Diverse Citizens in Global Times: Rethinking Theory and Practice

    ERIC Educational Resources Information Center

    Rubin, Beth C., Ed.; Giarelli, James M., Ed.

    2007-01-01

    This book explores four interrelated themes: rethinking civic education in light of the diversity of U.S. society; re-examining these notions in an increasingly interconnected global context; re-considering the ways that civic education is researched and practiced; and taking stock of where we are currently through use of an historical…

  16. Building Reading Resilience: Re-Thinking Reading for the Literary Studies Classroom

    ERIC Educational Resources Information Center

    Douglas, Kate; Barnett, Tully; Poletti, Anna; Seaboyer, Judith; Kennedy, Rosanne

    2016-01-01

    This paper introduces the concept of "reading resilience": students' ability to read and interpret complex and demanding literary texts by drawing on advanced, engaged, critical reading skills. Reading resilience is a means for rethinking the place and pedagogies of close reading in the contemporary literary studies classroom. Our…

  17. Rethinking Research Supervision: Some Reflections from the Field of Employment Relations

    ERIC Educational Resources Information Center

    Bingham, Cecilie; Durán-Palma, Fernando

    2014-01-01

    This essay offers some reflections for the theory and practice of research supervision drawn from the field of employment relations. It argues that rethinking supervision in terms of the employment relationship can advance dialogue and debate about supervision. This is twofold. (1) Reframing supervision in terms of the employment relationship can…

  18. Rethinking Well-Child Care: Teaching Parents to Teach Their Children?

    ERIC Educational Resources Information Center

    Duby, John C.

    2013-01-01

    Pediatricians have been challenged to rethink the schedule, content, and structure of well-child care. There is growing recognition of the need to include a focus on promoting healthy social and emotional development in the context of the parent-child relationship to minimize exposure to toxic stress and reduce the later burden of adult disease.…

  19. Rethinking Multicultural Education for the Next Generation: The New Empathy and Social Justice

    ERIC Educational Resources Information Center

    Dolby, Nadine

    2012-01-01

    "Rethinking Multicultural Education for the Next Generation" builds on the legacy of social justice multicultural education, while recognizing the considerable challenges of reaching today's college students. By drawing on breakthrough research in two fields--neuroscience and animal studies--Nadine Dolby argues that empathy is an underlying…

  20. Rethinking Composing in a Digital Age: Authoring Literate Identities through Multimodal Storytelling

    ERIC Educational Resources Information Center

    Vasudevan, Lalitha; Schultz, Katherine; Bateman, Jennifer

    2010-01-01

    In this article, the authors engage the theoretical lens of multimodality in rethinking the practices and processes of composing in classrooms. Specifically, they focus on how learning new composing practices led some fifth-grade students to author new literate identities--what they call authorial stances--in their classroom community. Their…

  1. Rethinking Conventional Teaching in Language Learning and Proposing Edmodo as Intervention: A Qualitative Analysis

    ERIC Educational Resources Information Center

    Mokhtar, Farha Alia

    2016-01-01

    In recent times, educators are urged to transform the techniques in conducting language learning by incorporating technological tools because new technologies stimulate an explosion of new methods for teaching and learning. This article emphasizes the conventional teaching pedagogy and the urgency to rethink its practice in language learning while…

  2. Rethinking Communication in Innovation Processes: Creating Space for Change in Complex Systems

    ERIC Educational Resources Information Center

    Leeuwis, Cees; Aarts, Noelle

    2011-01-01

    This paper systematically rethinks the role of communication in innovation processes, starting from largely separate theoretical developments in communication science and innovation studies. Literature review forms the basis of the arguments presented. The paper concludes that innovation is a collective process that involves the contextual…

  3. Literature. CUNY Panel: Rethinking the Disciplines. Women in the Curriculum Series.

    ERIC Educational Resources Information Center

    Hartman, Joan E.; de Filippis, Daisy Cocco; Kruger, Steven F.; O'Driscoll, Sally; Ling, Amy; Webb, Barbara J.

    This collection of six essays examines the ways in which literature, as a discipline, reflects ongoing scholarship on gender, race, ethnicity, social class, and sexual orientation. In "Rethinking the Discipline of Literature: Gender," Joan E. Hartman presents the results of a Modern Language Association survey that highlights the…

  4. Rethinking Our Classrooms: Teaching for Equity and Justice. Volume 2. Revised Edition

    ERIC Educational Resources Information Center

    Bigelow, Bill, Ed.

    2004-01-01

    With more than 180,000 copies in print, the first volume of "Rethinking Our Classrooms" broke new ground, providing teachers with hands-on ways to promote values of community, justice, and equality--and build students' academic skills. This companion volume continues in that tradition, presenting a rich new collection of…

  5. Rethinking Undergraduate Mathematics Education: The Importance of Classroom Climate and Self-Efficacy on Mathematics Achievement

    ERIC Educational Resources Information Center

    Peters, Michelle Lynn; Kortecamp, Karen

    2010-01-01

    Given the growing societal demand for a more mathematically proficient work force, mathematics proficiency is viewed as a necessary component for success in today's world. To ensure proficiency, undergraduate institutions may need to "rethink" their instructional approaches to teaching mathematics. Understanding the influence of classroom climate…

  6. Rethinking Approaches to Working with Children Who Challenge: Action Learning for Emancipatory Practice

    ERIC Educational Resources Information Center

    MacNaughton, Glenda; Hughes, Patrick; Smith, Kylie

    2007-01-01

    This article describes an action-learning project that helped teachers to rethink their approaches to children who challenge. The project enabled and encouraged teachers to reflect critically on why and how particular children challenged them and then to use their critical reflections to strengthen their capacity to work with those children. The…

  7. History versus Equilibrium Revisited: Rethinking Neoclassical Economics as the Foundation of Business Education

    ERIC Educational Resources Information Center

    Clark, Charles Michael Andres

    2014-01-01

    The financial crisis was partially caused by neoclassical economic theory and theorists. This failure has prompted business educators to rethink the role of neoclassical economics as the foundation of business education. The author connects this question to the more general critique of the scientific model of business education and the old…

  8. Rethinking Nutrition: Connecting Science and Practice in Early Childhood Settings, Revised Edition

    ERIC Educational Resources Information Center

    Nitzke, Susan; Riley, Dave; Ramminger, Ann; Jacobs, Georgine

    2015-01-01

    Nutrition has vital and long-lasting effects on children's development. Good nutrition helps children learn better and promotes lifelong healthy eating habits. Connecting current scientific research with best practices, "Rethinking Nutrition" provides information to help you meet and understand children's nutritional and developmental…

  9. Rethinking the Learning Society: Giorgio Agamben on Studying, Stupidity, and Impotence

    ERIC Educational Resources Information Center

    Lewis, Tyson E.

    2011-01-01

    In this article, the author rethinks critiques of the learning society using Giorgio Agamben's theory of potentiality. Summarizing several major contributions to our understanding of the limitations of the discourse of learning, the author proposes that critics thus far have failed to fully pinpoint the exact danger of learning. Importantly,…

  10. Rethinking Our Classrooms: Teaching for Equity and Justice. Volume 1. New Edition--Revised and Expanded

    ERIC Educational Resources Information Center

    Au, Wayne, Ed.; Bigelow, Bill, Ed.; Karp, Stan, Ed.

    2007-01-01

    Since the first edition was published in 1994, Rethinking Our Classrooms has sold over 180,000 copies. This revised and expanded edition includes new essays on: (1) science and environmental education; (2) immigration and language; (3) military recruitment; (4) teaching about the world through mathematics; and (5) gay and lesbian issues. Creative…

  11. Re-Thinking the "Thing" Sociomaterial Approaches to Understanding and Researching Learning in Work

    ERIC Educational Resources Information Center

    Fenwick, Tara

    2010-01-01

    Purpose: The purpose of this paper is to compare theoretical conceptions that reclaim and re-think material practice--"the thing" in the social and personal mix--specifically in terms of work activity and what is construed to be learning in that activity. Design/methodology/approach: The paper is theory-based. Three perspectives have been selected…

  12. Economising Education: From the Silent Revolution to Rethinking Education. A New Moment of Europeanisation of Education?

    ERIC Educational Resources Information Center

    Antunes, Fátima

    2016-01-01

    "Rethinking Education" (EC, 2012) suggests a new phase in European education policy. The constitution of education as a marketable service and the European (Higher) Education area as a market was pinpointed as an "implicit" agenda in the "silent revolution in education landscape" fostered by the open method of…

  13. Considering Pastoral Power: A Commentary on Aaron Schutz's "Rethinking Domination and Resistance: Challenging Postmodernism"

    ERIC Educational Resources Information Center

    Caughlan, Samantha

    2005-01-01

    In his "Rethinking Domination and Resistance: Challenging Postmodernism" ("Educational Researcher," January-February, 2004), Aaron Schutz questioned what he saw as postmodernism's fascination with the workings of pastoral modes of control, a preoccupation that prevents postmodernists from locating and opposing the disciplinary controls experienced…

  14. Development of Proteogenomic Approaches to Analyze the Role of Virus-Microbe Interactions in Shaping Natural Microbial Communities

    SciTech Connect

    Banfield, Jillian; Breitbart, Mya; VerBerkmoes, Nathan

    2014-04-25

    CRISPRs (clustered regularly interspaced short palindromic repeats) are adaptive immune systems in Bacteria and Archaea. Transcripts of the spacers that separate the repeats confer immunity through sequence identity with a targeted region (proto-spacer) in phage/viral, plasmid, or other foreign DNA. Short sequences immediately flanking the proto-spacer (proto-spacer adjacent motifs—PAMs) are important in both procuring spacers from and providing immunity to targeted sequences. New spacers are incorporated unidirectionally at the leader end of the CRISPR loci, thus recording a timeline of recent viral exposure. In the early phase of our research, we documented extremely rapid diversification of the CRISPR loci in natural populations [Tyson and Banfield, 2008] matched by high levels of sequence variation in natural viral populations [Andersson and Banfield, 2008]. Since then, in a genetically tractable model laboratory system, we have 1) tracked phage mutation and CRISPR diversification, and in a natural model system, we have 2) examined population history via over time, 3) investigated the timescale over which spacers become ineffective and the process by which ineffective spacers are removed, and 4) analyzed viral diversity. In addition to research activities, our group has organized five international CRISPR meetings, the fifth to be held at University of California, Berkeley in June 2012. Most importantly, the project provided the majority of funding support for Christine Sun (Ph.D. 2012).

  15. Study on the interaction of artificial and natural food colorants with human serum albumin: A computational point of view.

    PubMed

    Masone, Diego; Chanforan, Céline

    2015-06-01

    Due to the high amount of artificial food colorants present in infants' diets, their adverse effects have been of major concern among the literature. Artificial food colorants have been suggested to affect children's behavior, being hyperactivity the most common disorder. In this study we compare binding affinities of a group of artificial colorants (sunset yellow, quinoline yellow, carmoisine, allura red and tartrazine) and their natural industrial equivalents (carminic acid, curcumin, peonidin-3-glucoside, cyanidin-3-glucoside) to human serum albumin (HSA) by a docking approach and further refinement through atomistic molecular dynamics simulations. Due to the protein-ligand conformational interface complexity, we used collective variable driven molecular dynamics to refine docking predictions and to score them according to a hydrogen-bond criterion. With this protocol, we were able to rank ligand affinities to HSA and to compare between the studied natural and artificial food additives. Our results show that the five artificial colorants studied bind better to HSA than their equivalent natural options, in terms of their H-bonding network, supporting the hypothesis of their potential risk to human health.

  16. Comprehensive studies on the nature of interaction between carboxylated multi-walled carbon nanotubes and bovine serum albumin.

    PubMed

    Lou, Kai; Zhu, Zhaohua; Zhang, Hongmei; Wang, Yanqing; Wang, Xiaojiong; Cao, Jian

    2016-01-05

    Herein, the interaction between carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) and bovine serum albumin has been investigated by using circular dichroism, UV-vis, and fluorescence spectroscopic methods and molecular modeling in order to better understand the basic behavior of carbon nanotubes in biological systems. The spectral results showed that MWCNTs-COOH bound to BSA and induced the relatively large changes in secondary structure of protein by mainly hydrophobic forces and π-π stacking interactions. Thermal denaturation of BSA in the presence of MWCNTs-COOH indicated that carbon nanotubes acted as a structure destabilizer for BSA. In addition, the putative binding site of MWCNTs-COOH on BSA was near to domain II. With regard to human health, the present study could provide a better understanding of the biological properties, cytotocicity of surface modified carbon nanotubes.

  17. Natural history of interaction between Meteorus sp. Haliday, 1835 (Hymenoptera: Braconidae) and its hyperparasitoid Toxeumella albipes Girault, 1913 (Hymenoptera: Pteromalidae).

    PubMed

    Sobczak, J F; Maia, D P; Moura, J C M S; Costa, V A; Vasconcellos-Neto, J

    2012-02-01

    Some parasitoids build a cocoon mass that hangs in the host body until the adults emergence, which is an advantage against attack by predators who troll the vegetation in search of prey. However, such behaviour is not effective against the hyperparasitoid attacks. This study reports the interaction between the caterpillar Manduca sexta Linnaeus, 1763 (Lepidoptera, Sphingidae) parasitised by Meteorus sp. (Hymenoptera, Braconidae) larvae and its hyperparasitoid Toxeumella albipes (Hymenoptera, Pteromalidae). This is the first description of the attack and oviposition of T. albipes.

  18. Structural variability and the nature of intermolecular interactions in Watson-Crick B-DNA base pairs.

    PubMed

    Czyznikowska, Z; Góra, R W; Zaleśny, R; Lipkowski, P; Jarzembska, K N; Dominiak, P M; Leszczynski, J

    2010-07-29

    A set of nearly 100 crystallographic structures was analyzed using ab initio methods in order to verify the effect of the conformational variability of Watson-Crick guanine-cytosine and adenine-thymine base pairs on the intermolecular interaction energy and its components. Furthermore, for the representative structures, a potential energy scan of the structural parameters describing mutual orientation of the base pairs was carried out. The results were obtained using the hybrid variational-perturbational interaction energy decomposition scheme. The electron correlation effects were estimated by means of the second-order Møller-Plesset perturbation theory and coupled clusters with singles and doubles method adopting AUG-cc-pVDZ basis set. Moreover, the characteristics of hydrogen bonds in complexes, mimicking those appearing in B-DNA, were evaluated using topological analysis of the electron density. Although the first-order electrostatic energy is usually the largest stabilizing component, it is canceled out by the associated exchange repulsion in majority of the studied crystallographic structures. Therefore, the analyzed complexes of the nucleic acid bases appeared to be stabilized mainly by the delocalization component of the intermolecular interaction energy which, in terms of symmetry adapted perturbation theory, encompasses the second- and higher-order induction and exchange-induction terms. Furthermore, it was found that the dispersion contribution, albeit much smaller in terms of magnitude, is also a vital stabilizing factor. It was also revealed that the intermolecular interaction energy and its components are strongly influenced by four (out of six) structural parameters describing mutual orientation of bases in Watson-Crick pairs, namely shear, stagger, stretch, and opening. Finally, as a part of a model study, much of the effort was devoted to an extensive testing of the UBDB databank. It was shown that the databank quite successfully reproduces the

  19. Interactions among chemical components of Cocoa tea (Camellia ptilophylla Chang), a naturally low caffeine-containing tea species.

    PubMed

    Lin, Xiaorong; Chen, Zhongzheng; Zhang, Yuanyuan; Gao, Xiong; Luo, Wei; Li, Bin

    2014-06-01

    In the 1980s, a novel tea species, Cocoa tea (Camellia ptilophylla Chang), was discovered in Southern China with surprisingly low caffeine content (0.2% by dry weight). Although its health promoting characteristics have been known for a while, a very limited amount of scientific research has been focused on Cocoa tea. Herein, a systematic study on Cocoa tea and its chemical components, interactions and bioactivities was performed. YD tea (Yunnan Daye tea, Camellia sinensis), a tea species with a high caffeine content (5.8% by dry weight), was used as a control. By UV-Vis spectrometry, High Performance Liquid Chromatography (HPLC), and Flame Atomic Absorption Spectrometry (FAAS) for chemical composition analysis, C-2 epimeric isomers of tea catechins and theobromine were found to be the major catechins and methylxanthine in Cocoa tea, respectively. More gallated catechins, methylxanthines, and proteins were detected in Cocoa tea compared with YD tea. Moreover, the tendency of major components in Cocoa tea for precipitation was significantly higher than that in YD tea. Catechins, methylxanthines, proteins, iron, calcium, and copper were presumed to be the origins of molecular interactions in Cocoa tea and YD tea. The interactions between catechins and methylxanthines were highly related to the galloyl moiety in catechins and methyl groups in methylxanthines. In vitro anti-inflammatory activity assays revealed that Cocoa tea was a more potent inhibitor of nitric oxide (NO) in lipopolysaccharide (LPS)-stimulated macrophage cells (RAW 264.7) than YD tea. This study constructs a solid phytochemical foundation for further research on the mechanisms of molecular interactions and the integrated functions of Cocoa tea.

  20. Deviation from niche optima affects the nature of plant-plant interactions along a soil acidity gradient.

    PubMed

    He, Lei; Cheng, Lulu; Hu, Liangliang; Tang, Jianjun; Chen, Xin

    2016-01-01

    There is increasing recognition of the importance of niche optima in the shift of plant-plant interactions along environmental stress gradients. Here, we investigate whether deviation from niche optima would affect the outcome of plant-plant interactions along a soil acidity gradient (pH = 3.1, 4.1, 5.5 and 6.1) in a pot experiment. We used the acid-tolerant species Lespedeza formosa Koehne as the neighbouring plant and the acid-tolerant species Indigofera pseudotinctoria Mats. or acid-sensitive species Medicago sativa L. as the target plants. Biomass was used to determine the optimal pH and to calculate the relative interaction index (RII). We found that the relationships between RII and the deviation of soil pH from the target's optimal pH were linear for both target species. Both targets were increasingly promoted by the neighbour as pH values deviated from their optima; neighbours benefitted target plants by promoting soil symbiotic arbuscular mycorrhizal fungi, increasing soil organic matter or reducing soil exchangeable aluminium. Our results suggest that the shape of the curve describing the relationship between soil pH and facilitation/competition depends on the soil pH optima of the particular species.

  1. Monomeric nature of dengue virus NS3 helicase and thermodynamic analysis of the interaction with single-stranded RNA

    PubMed Central

    Gebhard, Leopoldo G.; Incicco, J. Jeremías; Smal, Clara; Gallo, Mariana; Gamarnik, Andrea V.; Kaufman, Sergio B.

    2014-01-01

    Dengue virus nonstructural protein 3 (NS3) is a multifunctional protein formed by a superfamily-2 RNA helicase linked to a protease domain. In this work, we report results from in vitro experiments designed to determine the oligomeric state of dengue virus NS3 helicase (NS3h) and to characterize fundamental properties of the interaction with single-stranded (ss)RNA. Pulsed field gradient-NMR spectroscopy was used to determine the effective hydrodynamic radius of NS3h, which was constant over a wide range of protein concentrations in the absence and presence of ssRNA. Size exclusion chromatography-static light scattering experiments showed that NS3h eluted as a monomeric molecule even in the presence of ssRNA. Binding of NS3h to ssRNA was studied by quantitative fluorescence titrations using fluorescein-labeled and unlabeled ssRNA oligonucleotides of different lengths, and the effect of the fluorescein label on the interaction parameters was also analyzed. Experimental results were well described by a statistical thermodynamic model based on the theory of non-specific interactions of large ligands to a one-dimensional lattice. We found that binding of NS3h to ssRNA oligonucleotides and to poly(A) is characterized by minimum and occluded binding site sizes both of 10 nucleotides and by a weak positive cooperativity between adjacent proteins. PMID:25223789

  2. What is special about expertise? Visual expertise reveals the interactive nature of real-world object recognition.

    PubMed

    Harel, Assaf

    2016-03-01

    Ever since Diamond and Carey (1986. J. Exp. Psychol.: Gen., vol. 115, pp. 107-117) seminal work, the main model for studying expertise in visual object recognition ("visual expertise") has been face perception. The underlying assumption was that since faces may be considered the ultimate domain of visual expertise, any face-processing signature might actually be a general characteristic of visual expertise. However, while humans are clearly experts in face recognition, visual expertise is not restricted to faces and can be observed in a variety of domains. This raises the question of whether face recognition is in fact the right model to study visual expertise, and if not, what are the common cognitive and neural characteristics of visual expertise. The current perspective article addresses this question by revisiting past and recent neuroimaging and behavioural works on visual expertise. The view of visual expertise that emerges from these works is that expertise is a unique phenomenon, with distinctive neural and cognitive characteristics. Specifically, visual expertise is a controlled, interactive process that develops from the reciprocal interactions between the visual system and multiple top-down factors, including semantic knowledge, top-down attentional control, and task relevance. These interactions enable the ability to flexibly access domain-specific information at multiple scales and levels guided by multiple recognition goals. Extensive visual experience with a given object category culminates in the recruitment of these multiple systems, and is reflected in widespread neural activity, extending well beyond visual cortex, to include higher-level cortical areas.

  3. Rethinking adaptation for a 4°C world.

    PubMed

    Stafford Smith, Mark; Horrocks, Lisa; Harvey, Alex; Hamilton, Clive

    2011-01-13

    With weakening prospects of prompt mitigation, it is increasingly likely that the world will experience 4°C and more of global warming. In such a world, adaptation decisions that have long lead times or that have implications playing out over many decades become more uncertain and complex. Adapting to global warming of 4°C cannot be seen as a mere extrapolation of adaptation to 2°C; it will be a more substantial, continuous and transformative process. However, a variety of psychological, social and institutional barriers to adaptation are exacerbated by uncertainty and long timeframes, with the danger of immobilizing decision-makers. In this paper, we show how complexity and uncertainty can be reduced by a systematic approach to categorizing the interactions between decision lifetime, the type of uncertainty in the relevant drivers of change and the nature of adaptation response options. We synthesize a number of issues previously raised in the literature to link the categories of interactions to a variety of risk-management strategies and tactics. Such application could help to break down some barriers to adaptation and both simplify and better target adaptation decision-making. The approach needs to be tested and adopted rapidly.

  4. Natural Compounds Interacting with Nicotinic Acetylcholine Receptors: From Low-Molecular Weight Ones to Peptides and Proteins

    PubMed Central

    Kudryavtsev, Denis; Shelukhina, Irina; Vulfius, Catherine; Makarieva, Tatyana; Stonik, Valentin; Zhmak, Maxim; Ivanov, Igor; Kasheverov, Igor; Utkin, Yuri; Tsetlin, Victor

    2015-01-01

    Nicotinic acetylcholine receptors (nAChRs) fulfill a variety of functions making identification and analysis of nAChR subtypes a challenging task. Traditional instruments for nAChR research are d-tubocurarine, snake venom protein α-bungarotoxin (α-Bgt), and α-conotoxins, neurotoxic peptides from Conus snails. Various new compounds of different structural classes also interacting with nAChRs have been recently identified. Among the low-molecular weight compounds are alkaloids pibocin, varacin and makaluvamines C and G. 6-Bromohypaphorine from the mollusk Hermissenda crassicornis does not bind to Torpedo nAChR but behaves as an agonist on human α7 nAChR. To get more selective α-conotoxins, computer modeling of their complexes with acetylcholine-binding proteins and distinct nAChRs was used. Several novel three-finger neurotoxins targeting nAChRs were described and α-Bgt inhibition of GABA-A receptors was discovered. Information on the mechanisms of nAChR interactions with the three-finger proteins of the Ly6 family was found. Snake venom phospholipases A2 were recently found to inhibit different nAChR subtypes. Blocking of nAChRs in Lymnaea stagnalis neurons was shown for venom C-type lectin-like proteins, appearing to be the largest molecules capable to interact with the receptor. A huge nAChR molecule sensible to conformational rearrangements accommodates diverse binding sites recognizable by structurally very different compounds. PMID:26008231

  5. From Perspectiva Artificialis to Cyberspace: Game-Engine and the Interactive Visualization of Natural Light in the Interior of the Building

    NASA Astrophysics Data System (ADS)

    Christakou, Evangelos Dimitrios; Silva, Neander Furtado; Lima, Ecilamar Maciel

    In order to support the early stages of conceptual design, the architect used throughout the years, mockups - scaled physical models - or perspective drawings that intended to predict architectural ambience before its effective construction. This paper studies the real time interactive visualization, focused on one of the most important aspects inside building space: the natural light. However, the majority of physically-based algorithms currently existing was designed for the synthesis of static images which may not take into account how to rebuild the scene - in real time - when the user is doing experiments to change certain properties of design. In this paper we show a possible solution for this problem.

  6. Mycophagous growth of Collimonas bacteria in natural soils, impact on fungal biomass turnover and interactions with mycophagous Trichoderma fungi.

    PubMed

    Höppener-Ogawa, Sachie; Leveau, Johan H J; van Veen, Johannes A; De Boer, Wietse

    2009-02-01

    Bacteria of the genus Collimonas are widely distributed in soils, although at low densities. In the laboratory, they were shown to be mycophagous, that is, they are able to grow at the expense of living hyphae. However, so far the importance of mycophagy for growth and survival of collimonads in natural soil habitats is unknown. Using a Collimonas-specific real-time PCR assay, we show here that the invasion of field soils by fungal hyphae (Absidia sp.) resulted in a short-term, significant increase (average fourfold) of indigenous collimonads. No such responses were observed for other soil bacteria studied (Pseudomonas, Burkholderia, PCR-denaturing gradient gel electrophoresis patterns of total bacteria and Burkholderia). Hence, it appears that the stimulation of growth of Collimonas bacteria by fungal hyphae is not common among other soil bacteria. In the same field soils, Trichoderma, a fungal genus known for mycophagous (mycoparasitic) growth, increased upon introduction of Absidia hyphae. Hence, mycophagous growth by Collimonas and Trichoderma can occur in the same soils. However, in controlled experiments (sand microcosms), collimonads appeared to have a negative effect on mycophagous growth of a Trichoderma strain. The effect of mycophagous growth of collimonads on fungal biomass dynamics was studied in sand microcosms using the same Absidia sp. as a test fungus. The growth of collimonads did not cause a significant reduction in the Absidia biomass. Overall, the study indicates that mycophagous nutrition may be important for collimonads in natural soils, but the impact on fungal biomass turnover is likely to be minor.

  7. Multiple loci and genetic interactions involving flowering time genes regulate stem branching among natural variants of Arabidopsis.

    PubMed

    Huang, Xueqing; Ding, Jia; Effgen, Sigi; Turck, Franziska; Koornneef, Maarten

    2013-08-01

    Shoot branching is a major determinant of plant architecture. Genetic variants for reduced stem branching in the axils of cauline leaves of Arabidopsis were found in some natural accessions and also at low frequency in the progeny of multiparent crosses. Detailed genetic analysis using segregating populations derived from backcrosses with the parental lines and bulked segregant analysis was used to identify the allelic variation controlling reduced stem branching. Eight quantitative trait loci (QTLs) contributing to natural variation for reduced stem branching were identified (REDUCED STEM BRANCHING 1-8 (RSB1-8)). Genetic analysis showed that RSB6 and RSB7, corresponding to flowering time genes FLOWERING LOCUS C (FLC) and FRIGIDA (FRI), epistatically regulate stem branching. Furthermore, FLOWERING LOCUS T (FT), which corresponds to RSB8 as demonstrated by fine-mapping, transgenic complementation and expression analysis, caused pleiotropic effects not only on flowering time, but, in the specific background of active FRI and FLC alleles, also on the RSB trait. The consequence of allelic variation only expressed in late-flowering genotypes revealed novel and thus far unsuspected roles of several genes well characterized for their roles in flowering time control.

  8. Towards a Complete Commonsense Theory of Motion: The interaction of dimensions in children's predictions of natural object motion

    NASA Astrophysics Data System (ADS)

    Hast, Michael; Howe, Christine

    2013-07-01

    Events involving motion in fall are differentiated psychologically from events involving horizontal motion. Do children associate motion down inclines more with motion along horizontals or more with motion in fall, or do they even treat it as an integration of the two? The question was raised over 20 years ago but never satisfactorily answered, so the principal aim of the reported research was to take matters forward. Children (n = 144) aged 5-11 years were assessed while predicting natural dynamic events along a horizontal, in fall and down an incline. They were required to make predictions of speed with heavy and light balls and under changes in incline heights. The results show that, consistent with previous work, faster horizontal motion was associated with the light ball across all ages, whereas faster fall was associated with the heavy ball. However, while the younger children predicted faster incline motion for the lighter ball, there was a shift in this conception towards older children predicting faster motion for the heavier ball. Understanding of how changes in incline height affect speed was generally good, with this aspect of the study helping to establish how children perceive diagonal dimensions. How supported horizontal motion and unsupported fall motion may affect children's changing understanding of incline motion is discussed, thus providing more complete insight into children's understanding of natural object motion than has been established so far.

  9. Physical nature of interactions in Zn(II) complexes with 2,2'-bipyridyl: quantum theory of atoms in molecules (QTAIM), interacting quantum atoms (IQA), noncovalent interactions (NCI), and extended transition state coupled with natural orbitals for chemical valence (ETS-NOCV) comparative studies.

    PubMed

    Cukrowski, Ignacy; de Lange, Jurgens H; Mitoraj, Mariusz

    2014-01-23

    In the present account factors determining the stability of ZnL, ZnL2, and ZnL3 complexes (L = bpy, 2,2′-bipyridyl) were characterized on the basis of various techniques: the quantum theory of atoms in molecules (QTAIM), energy decomposition schemes based on interacting quantum atoms (IQA), and extended transition state coupled with natural orbitals for chemical valence (ETS-NOCV). Finally, the noncovalent interactions (NCI) index was also applied. All methods consistently indicated that the strength of the coordination bonds, Zn–O and Zn–N, decreases from ZnL to ZnL3. Importantly, it has been identified that the strength of secondary intramolecular heteropolar hydrogen bonding interactions, CH···O and CH···N, increases when going from ZnL to ZnL3. A similar trend appeared to be valid for the π-bonding as well as electrostatic stabilization. In addition to the above leading bonding contributions, all techniques suggested the existence of very subtle, but non-negligible additional stabilization from the CH···HC electronic exchange channel; these interactions are the weakest among all considered here. From IQA it was found that the local diatomic interaction energy, Eint(H,H), amounts at HF to −2.5, −2.7, and −2.9 kcal mol(–1) for ZnL, ZnL2, and ZnL3, respectively (−2.1 kcal mol(–1) for ZnL at MP2). NOCV-based deformation density channels showed that formation of CH--HC contacts in Zn complexes causes significant polarization of σ(C–H) bonds, which accordingly leads to charge accumulation in the CH···HC bay region. Charge depletion from σ(C–H) bonds was also reflected in the calculated spin–spin (1)J(C–H) coupling constants, which decrease from 177.06 Hz (ZnL) to 173.87 Hz (ZnL3). This last result supports our findings of an increase in the local electronic CH···HC stabilization from ZnL to ZnL3 found from QTAIM, IQA, and ETS-NOCV. Finally, this work unites for the first time the results from four methods that are widely

  10. Nature of the interaction between rare gas atoms and transition metal doped silicon clusters: the role of shielding effects.

    PubMed

    Ngan, Vu Thi; Janssens, Ewald; Claes, Pieterjan; Fielicke, André; Nguyen, Minh Tho; Lievens, Peter

    2015-07-21

    Mass spectrometry experiments show an exceptionally weak bonding between Si7Mn(+) and rare gas atoms as compared to other exohedrally transition metal (TM) doped silicon clusters and other SinMn(+) (n = 5-10) sizes. The Si7Mn(+) cluster does not form Ar complexes and the observed fraction of Xe complexes is low. The interaction of two cluster series, SinMn(+) (n = 6-10) and Si7TM(+) (TM = Cr, Mn, Cu, and Zn), with Ar and Xe is investigated by density functional theory calculations. The cluster-rare gas binding is for all clusters, except Si7Mn(+) and Si7Zn(+), predominantly driven by short-range interaction between the TM dopant and the rare gas atoms. A high s-character electron density on the metal atoms in Si7Mn(+) and Si7Zn(+) shields the polarization toward the rare gas atoms and thereby hinders formation of short-range complexes. Overall, both Ar and Xe complexes are similar except that the larger polarizability of Xe leads to larger binding energies.

  11. Nature of point defects on SiO2/Mo(112) thin films and their interaction with Au atoms.

    PubMed

    Martinez, Umberto; Giordano, Livia; Pacchioni, Gianfranco

    2006-08-31

    We have studied by means of periodic DFT calculations the structure and properties of point defects at the surface of ultrathin silica films epitaxially grown on Mo(112) and their interaction with adsorbed Au atoms. For comparison, the same defects have been generated on an unsupported silica film with the same structure. Four defects have been considered: nonbridging oxygen (NBO, [triple bond]Si-O(*)), Si dangling bond (E' center, [triple bond]Si(*)), oxygen vacancy (V(O), [triple bond]Si-Si[triple bond]), and peroxo group ([triple bond]Si-O-O-Si[triple bond]), but only the NBO and the V(O) centers are likely to form on the SiO(2)/Mo(112) films under normal experimental conditions. The [triple bond]Si-O(*) center captures one electron from Mo forming a silanolate group, [triple bond]Si-O(-), sign of a direct interaction with the metal substrate. Apart from the peroxo group, which is unreactive, the other defects bind strongly the Au atom forming stable surface complexes, but their behavior may differ from that of the same centers generated on an unsupported silica film. This is true in particular for the two most likely defects considered, the nonbridging oxygen, [triple bond]Si-O(*), and the oxygen vacancy, [triple bond]Si-Si[triple bond].

  12. Deepwater Horizon Oil-Protection Sand Berm and its Morphologic Interactions with a Natural Barrier Island: an Overview

    NASA Astrophysics Data System (ADS)

    Sallenger, A. H.; Plant, N. G.; Flocks, J.; Long, J. W.; Miselis, J. L.; Sherwood, C. R.; Hansen, M.; Nayegandhi, A.; Wright, W.

    2011-12-01

    After the Deepwater Horizon explosion and oil spill, Louisiana received permission to build a sand berm parallel to and offshore of the ~30-km-long Chandeleur Islands to capture floating oil and keep it from reaching mainland marshes. The berm was built with dredged sand to a height of approximately 2 m above mean sea level and within 100 m of the Gulf-side of the natural barrier island. Here, we update the status of the sand berm and how its morphology has evolved since construction began in June 2010. This is part of a study of morphologic change involving time series of airborne lidar topographic and bathymetric surveys, boat acoustic bathymetric surveys, satellite imagery, and modeling of sediment transport. Waves and sea level are being monitored with models and in-situ sensors. We will examine, as of our latest surveys, whether the introduction of new sand from the berm has significantly changed peak elevations, Dhigh, along the natural islands and hence changed island vulnerability to being overtopped by storm-driven water levels, such as still-water level (η, due to tides, surge, and wave setup) and runup (R, due to swash). Vulnerabilities to overwash, where R > Dhigh, and inundation, where η > Dhigh, will be identified. We will investigate the impacts on the berm and island of extra-tropical storms through June 2011 and tropical storms through the hurricane season of summer and early fall 2011. For example, during a storm in early January 2011, significant wave heights of 4.9 m generated runup on the berm where R > Dhigh. Four breaches were cut through the berm, the largest 590 m wide. This study provides a unique opportunity to investigate the wave and current transport of a large quantity of introduced sand and determine whether and how the sand nourishes a severely eroding barrier island.

  13. Outer satellite atmospheres: Their extended nature and planetary interactions. [sodium cloud of Io, hydrogen torus of Titan, and comet atmospheres

    NASA Technical Reports Server (NTRS)

    Smyth, W. H.

    1980-01-01

    Highly developed numerical models are applied to interpret extended-atmosphere data for the sodium cloud of Io and the hydrogen torus of Titan. Solar radiation pressure was identified and verified by model calculations as the mechanism to explain two different east-west asymmetries observed in the sodium cloud. Analysis of sodium line profile data, suggesting that a Jupiter magnetospheric wind may be responsible for high speed sodium atoms emitted from Io, and preliminary modeling of the interaction of the Io plasma torus and Io's sodium cloud are also reported. Models presented for Titan's hydrogen torus are consistent both with the recent Pioneer 11 measurements and earlier Earth-orbiting observations by the Copernicus satellite. Progress is reported on developing models for extended gas and dust atmospheres of comets.

  14. Nature versus nurture: A systematic approach to elucidate gene-environment interactions in the development of myopic refractive errors.

    PubMed

    Miraldi Utz, Virginia

    2017-01-01

    Myopia is the most common eye disorder and major cause of visual impairment worldwide. As the incidence of myopia continues to rise, the need to further understand the complex roles of molecular and environmental factors controlling variation in refractive error is of increasing importance. Tkatchenko and colleagues applied a systematic approach using a combination of gene set enrichment analysis, genome-wide association studies, and functional analysis of a murine model to identify a myopia susceptibility gene, APLP2. Differential expression of refractive error was associated with time spent reading for those with low frequency variants in this gene. This provides support for the longstanding hypothesis of gene-environment interactions in refractive error development.

  15. Evolution of long-toothed fishes and the changing nature of fish-benthos interactions on coral reefs.

    PubMed

    Bellwood, David R; Hoey, Andrew S; Bellwood, Orpha; Goatley, Christopher H R

    2014-01-01

    Interactions between fishes and the benthos have shaped the development of marine ecosystems since at least the early Mesozoic. Here, using the morphology of fish teeth as an indicator of feeding abilities, we quantify changes over the last 240 million years of reef fish evolution. Fossil and extant coral reef fish assemblages reveal exceptional stasis in tooth design over time, with one notable exception, a distinct long-toothed form. Arising only in the last 40 million years, these long-toothed fishes have bypassed the invertebrate link in the food chain, feeding directly on benthic particulate material. With the appearance of elongated teeth, these specialized detritivores have moved from eating invertebrates to eating the food of invertebrates. Over evolutionary time, fishes have slid back down the food chain.

  16. Inhibition of preS1-hepatocyte interaction by an array of recombinant human antibodies from naturally recovered individuals

    PubMed Central

    Sankhyan, Anurag; Sharma, Chandresh; Dutta, Durgashree; Sharma, Tarang; Chosdol, Kunzang; Wakita, Takaji; Watashi, Koichi; Awasthi, Amit; Acharya, Subrat K.; Khanna, Navin; Tiwari, Ashutosh; Sinha, Subrata

    2016-01-01

    Neutralizing monoclonal antibodies are being found to be increasingly useful in viral infections. In hepatitis B infection, antibodies are proven to be useful for passive prophylaxis. The preS1 region (21–47a.a.) of HBV contains the viral hepatocyte-binding domain crucial for its attachment and infection of hepatocytes. Antibodies against this region are neutralizing and are best suited for immune-based neutralization of HBV, especially in view of their not recognizing decoy particles. Anti-preS1 (21–47a.a.) antibodies are present in serum of spontaneously recovered individuals. We generated a phage-displayed scFv library using circulating lymphocytes from these individuals and selected four preS1-peptide specific scFvs with markedly distinct sequences from this library. All the antibodies recognized the blood-derived and recombinant preS1 containing antigens. Each scFv showed a discrete binding signature, interacting with different amino acids within the preS1-peptide region. Ability to prevent binding of the preS1 protein (N-terminus 60a.a.) to HepG2 cells stably expressing hNTCP (HepG2-hNTCP-C4 cells), the HBV receptor on human hepatocytes was taken as a surrogate marker for neutralizing capacity. These antibodies inhibited preS1-hepatocyte interaction individually and even better in combination. Such a combination of potentially neutralizing recombinant antibodies with defined specificities could be used for preventing/managing HBV infections, including those by possible escape mutants. PMID:26888694

  17. Inhibition of preS1-hepatocyte interaction by an array of recombinant human antibodies from naturally recovered individuals.

    PubMed

    Sankhyan, Anurag; Sharma, Chandresh; Dutta, Durgashree; Sharma, Tarang; Chosdol, Kunzang; Wakita, Takaji; Watashi, Koichi; Awasthi, Amit; Acharya, Subrat K; Khanna, Navin; Tiwari, Ashutosh; Sinha, Subrata

    2016-02-18

    Neutralizing monoclonal antibodies are being found to be increasingly useful in viral infections. In hepatitis B infection, antibodies are proven to be useful for passive prophylaxis. The preS1 region (21-47a.a.) of HBV contains the viral hepatocyte-binding domain crucial for its attachment and infection of hepatocytes. Antibodies against this region are neutralizing and are best suited for immune-based neutralization of HBV, especially in view of their not recognizing decoy particles. Anti-preS1 (21-47a.a.) antibodies are present in serum of spontaneously recovered individuals. We generated a phage-displayed scFv library using circulating lymphocytes from these individuals and selected four preS1-peptide specific scFvs with markedly distinct sequences from this library. All the antibodies recognized the blood-derived and recombinant preS1 containing antigens. Each scFv showed a discrete binding signature, interacting with different amino acids within the preS1-peptide region. Ability to prevent binding of the preS1 protein (N-terminus 60a.a.) to HepG2 cells stably expressing hNTCP (HepG2-hNTCP-C4 cells), the HBV receptor on human hepatocytes was taken as a surrogate marker for neutralizing capacity. These antibodies inhibited preS1-hepatocyte interaction individually and even better in combination. Such a combination of potentially neutralizing recombinant antibodies with defined specificities could be used for preventing/managing HBV infections, including those by possible escape mutants.

  18. Past agricultural land use and present-day fire regimes can interact to determine the nature of seed predation.

    PubMed

    Stuhler, John D; Orrock, John L

    2016-06-01

    Historical agriculture and present-day fire regimes can have significant effects on contemporary ecosystems. Although past agricultural land use can lead to long-term changes in plant communities, it remains unclear whether these persistent land-use legacies alter plant-consumer interactions, such as seed predation, and whether contemporary disturbance (e.g., fire) alters the effects of historical agriculture on these interactions. We conducted a study at 27 sites distributed across 80,300 ha in post-agricultural and non-agricultural longleaf pine woodlands with different degrees of fire frequency to test the hypothesis that past and present-day disturbances that alter plant communities can subsequently alter seed predation. We quantified seed removal by arthropods and rodents for Tephrosia virginiana and Vernonia angustifolia, species of conservation interest. We found that the effects of land-use history and fire frequency on seed removal were contingent on granivore guild and microhabitat characteristics. Tephrosia virginiana removal was greater in low fire frequency sites, due to greater seed removal by rodents. Although overall removal of V. angustifolia did not differ among habitats, rodents removed more seeds than arthropods at post-agricultural sites and non-agricultural sites with low fire frequencies, but not at non-agricultural sites with high fire frequencies. Land-use history and fire frequency also affected the relationship between microhabitat characteristics and removal of V. angustifolia. Our results suggest that historical agriculture and present-day fire regimes may alter seed predation by shifting the impact of rodent and arthropod seed predators among habitats, with potential consequences for the establishment of rare plant species consumed by one or both predators.

  19. Interaction of Bovine Peripheral Blood Polymorphonuclear Cells and Leptospira Species; Innate Responses in the Natural Bovine Reservoir Host

    PubMed Central

    Wilson-Welder, Jennifer H.; Frank, Ami T.; Hornsby, Richard L.; Olsen, Steven C.; Alt, David P.

    2016-01-01

    Cattle are the reservoir hosts of Leptospira borgpetersenii serovar Hardjo, and can also be reservoir hosts of other Leptospira species such as L. kirschneri, and Leptospira interrogans. As a reservoir host, cattle shed Leptospira, infecting other animals, including humans. Previous studies with human and murine neutrophils have shown activation of neutrophil extracellular trap or NET formation, and upregulation of inflammatory mediators by neutrophils in the presence of Leptospira. Humans, companion animals and most widely studied models of Leptospirosis are of acute infection, hallmarked by systemic inflammatory response, neutrophilia, and septicemia. In contrast, cattle exhibit chronic infection with few outward clinical signs aside from reproductive failure. Taking into consideration that there is host species variation in innate immunity, especially in pathogen recognition and response, the interaction of bovine peripheral blood polymorphonuclear cells (PMNs) and several Leptospira strains was evaluated. Studies including bovine-adapted strains, human pathogen strains, a saprophyte and inactivated organisms. Incubation of PMNs with Leptospira did induce slight activation of neutrophil NETs, greater than unstimulated cells but less than the quantity from E. coli P4 stimulated PMNs. Very low but significant from non-stimulated, levels of reactive oxygen peroxides were produced in the presence of all Leptospira strains and E. coli P4. Similarly, significant levels of reactive nitrogen intermediaries (NO2) was produced from PMNs when incubated with the Leptospira strains and greater quantities in the presence of E. coli P4. PMNs incubated with Leptospira induced RNA transcripts of IL-1β, MIP-1α, and TNF-α, with greater amounts induced by live organisms when compared to heat-inactivated leptospires. Transcript for inflammatory cytokine IL-8 was also induced, at similar levels regardless of Leptospira strain or viability. However, incubation of Leptospira strains

  20. Study on Karst Rock Desertification by Human-Nature Interaction: A Case Study of Fengshan County of Guangxi, China

    NASA Astrophysics Data System (ADS)

    Zhou, G.; Su, C.; Zhang, R.; Shi, Y.; Liu, Y.; Ma, Y.

    2014-11-01

    Rocky desertification is a process of soil erosion leading to the bareness of bedrock, and is a kind of typical natural disaster in karst areas, which seriously constrains the developments of local society and economy. This paper studies the impact of human activities on the changes of rocky desertification. With the interpretation of remote sensing images of Fengshan County, GuangXi, China covering 1990, 1995 and 2005, this paper analyzes the relationship of the changes of social and economic index (including population density, agricultural population, rural per capital net income, and farmland) and the changes of rocky desertification in recent 15 years. The results indicate that: in recent 15 years, the average annual growth rate of rocky desertification, rate of change of population density, agricultural population, rural per capita net income, and farmland area are 8.7375 km2 /year, 0.7 person/km2.year, 1153 person/year, 85 Yuan/year, and -269.1 ha/year, respectively. The first three of social and economic indicators at different degrees of growth, show a positive correlation with rocky desertification change. However, farmland area, which has been diminishing, shows a negative correlation with rocky desertification. The influence of human activities for karst rocky desertification can be regarded as population growth - steep slope reclamation - the destruction of vegetation - erosion - rocky desertification - poverty.

  1. Interpersonal frontopolar neural synchronization in group communication: An exploration toward fNIRS hyperscanning of natural interactions.

    PubMed

    Nozawa, Takayuki; Sasaki, Yukako; Sakaki, Kohei; Yokoyama, Ryoichi; Kawashima, Ryuta

    2016-06-01

    Research of interpersonal neural synchronization (INS) using functional near-infrared spectroscopy (fNIRS) hyperscanning is an expanding nascent field. This field still requires the accumulation of findings and establishment of analytic standards. In this study, we therefore intend to extend fNIRS-based INS research in three directions: (1) verifying the enhancement of frontopolar INS by natural and unstructured verbal communication involving more than two individuals; (2) examining timescale dependence of the INS modulation; and (3) evaluating the effects of artifact reduction methods in capturing INS. We conducted an fNIRS hyperscanning study while 12 groups of four subjects were engaged in cooperative verbal communication. Corresponding to the three objectives, our analyses of the data (1) confirmed communication-enhanced frontopolar INS, as expected from the region's roles in social communication; (2) revealed the timescale dependency in the INS modulation, suggesting the merit of evaluating INS in fine timescale bins; and (3) determined that removal of the skin blood flow component engenders substantial improvement in sensitivity to communication-enhanced INS and segregation from artifactual synchronization, and that caution for artifact reduction preprocessing is needed to avoid excessive removal of the neural fluctuation component. Accordingly, this study provides a prospective technical basis for future hyperscanning studies during daily communicative activities.

  2. Single-step scalable conversion of waste natural oils to carbon nanowhiskers and their interaction with mammalian cells

    NASA Astrophysics Data System (ADS)

    Datta, Abheek; Dutta, Priyanka; Sadhu, Anustup; Maiti, Sankar; Bhattacharyya, Sayan

    2013-07-01

    Waste cooking oil has daily deliberate hazardous effects on human health due to consumption of re-cooked oil and on the environment from disposal of the waste oil. These hazards can be controlled if there are ways to economically convert the waste oils into industrially relevant materials. Large-scale controlled catalytic conversion of the waste natural oils to carbon nanowhiskers (CNWs; diameter: 98-191 nm, length: ≤2 μm) was achieved by a one-pot, environmentally friendly process. The no-cost CNWs consist of carbon spirals with spacing between two adjacent layers at 3.1 ± 0.2 nm and arranged perpendicular to the whisker axis. The reactions were performed inside a sealed container at 500-850 °C and autogenic pressure for 4-10 h. It was demonstrated that the gaseous pressure from the decomposition of the fatty acids was crucial for formation of the semi-graphitic filamentous structures. The dilute acid-washed catalyst free CNWs were found to be negligibly toxic to the mammalian cells and can be localized inside the cell nucleus. The cellular internalization studies of the fluorescent CNWs demonstrated their viability as potential delivery vehicles into the mammalian cells.

  3. The interaction of natural organic matter with iron in a wetland (Tennessee Park, Colorado) receiving acid mine drainage

    USGS Publications Warehouse

    Peiffer, Stefan; Walton-Day, Katherine; Macalady, Donald L.

    1999-01-01

    Pore water from a wetland receiving acid mine drainage was studied for its iron and natural organic matter (NOM) geochemistry on three different sampling dates during summer 1994. Samples were obtained using a new sampling technique that is based on screened pipes of varying length (several centimeters), into which dialysis vessels can be placed and that can be screwed together to allow for vertical pore-water sampling. The iron concentration increased with time (through the summer) and had distinct peaks in the subsurface. Iron was mainly in the ferrous form; however, close to the surface, significant amounts of ferric iron (up to 40% of 2 mmol L-1 total iron concentration) were observed. In all samples studied, iron was strongly associated with NOM. Results from laboratory experiments indicate that the NOM stabilizes the ferric iron as small iron oxide colloids (able to pass a 0.45μm dialysis membrane). We hypothesize that, in the pore water of the wetland, the high NOM concentrations (>100 mg C L-1) allow formation of such colloids at the redoxcline close to the surface and at the contact zone to the adjacent oxic aquifer. Therefore, particle transport along flow paths and resultant export of ferric iron from the wetland into ground water might be possible.

  4. Mortality trajectory analysis reveals the drivers of sex-specific epidemiology in natural wildlife-disease interactions.

    PubMed

    McDonald, Jennifer L; Smith, Graham C; McDonald, Robbie A; Delahay, Richard J; Hodgson, Dave

    2014-09-07

    In animal populations, males are commonly more susceptible to disease-induced mortality than females. However, three competing mechanisms can cause this sex bias: weak males may simultaneously be more prone to exposure to infection and mortality; being 'male' may be an imperfect proxy for the underlying driver of disease-induced mortality; or males may experience increased severity of disease-induced effects compared with females. Here, we infer the drivers of sex-specific epidemiology by decomposing fixed mortality rates into mortality trajectories and comparing their parameters. We applied Bayesian survival trajectory analysis to a 22-year longitudinal study of a population of badgers (Meles meles) naturally infected with bovine tuberculosis (bTB). At the point of infection, infected male and female badgers had equal mortality risk, refuting the hypothesis that acquisition of infection occurs in males with coincidentally high mortality. Males and females exhibited similar levels of heterogeneity in mortality risk, refuting the hypothesis that maleness is only a proxy for disease susceptibility. Instead, sex differences were caused by a more rapid increase in male mortality rates following infection. Males are indeed more susceptible to bTB, probably due to immunological differences between the sexes. We recommend this mortality trajectory approach for the study of infection in animal populations.

  5. Interaction of natural killer cells with neutrophils exerts a significant antitumor immunity in hematopoietic stem cell transplantation recipients.

    PubMed

    Ueda, Ryosuke; Narumi, Kenta; Hashimoto, Hisayoshi; Miyakawa, Reina; Okusaka, Takuji; Aoki, Kazunori

    2016-01-01

    Autologous hematopoietic stem cell transplantation (HSCT) can induce a strong antitumor immunity by homeostatic proliferation (HP) of T cells and suppression of regulatory T cells following preconditioning-induced lymphopenia. However, the role of innate immunity including natural killer (NK) cells is still not understood. Here, first, we examined whether NK cells exert an antitumor effect after syngeneic HSCT in a murine colon cancer model. Flow cytometry showed that NK cells as well as T cells rapidly proliferated after HSCT, and the frequency of mature NK cells was increased in tumor during HP. Furthermore, NK cells undergoing HP were highly activated, which contributed to substantial tumor suppression. Then, we found that a large number of neutrophils accumulated in tumor early after syngeneic HSCT. It was recently reported that neutrophil-derived mediators modulate NK cell effector functions, and so we examined whether the neutrophils infiltrated in tumor are associated with NK cell-mediated antitumor effect. The depletion of neutrophils significantly impaired an activation of NK cells in tumor and increased the fraction of proliferative NK cells accompanied by a decrease in NK cell survival. The results suggested that neutrophils in tumor prevent NK cells from activation-induced cell death during HP, thus leading to a significant antitumor effect by NK cells. This study revealed a novel aspect of antitumor immunity induced by HSCT and may contribute to the development of an effective therapeutic strategy for cancer using HSCT.

  6. Theoretical study of the interaction between pyridine derivatives and atomic chlorine. Substituent effect and nature of the bonding

    NASA Astrophysics Data System (ADS)

    Sutradhar, Dipankar; Zeegers-Huyskens, Therese; Chandra, Asit K.

    2015-11-01

    The interaction of pyridine derivatives (H, 4-NH2, 4-CH3, 4-F, 4-CN, 4-NO2) with atomic chlorine is investigated theoretically by the density functional theory (DFT)-based LC-BLYP/aug-cc-pVDZ method. Pyridines and Cl° are held together by a (2c--3e) bond and the intermolecular distances range from 2.313 to 2.343 Å. The existence of a N…Cl bond is confirmed by the atom-in-molecule analysis of the systems. The binding energies of the adducts, ranging from -42.08 to -53.96 kJ mol-1, are linearly correlated to the proton affinity of the pyridines. The charge transfer from pyridine to Cl° varies between 0.222 and 0.277 e. The spin density analysis shows that the strongest complex has the highest (2c-3e) character. The CH bonds are contracted and the ν(CH) vibrations are blueshifted owing to the decrease in σ*(CH) occupation. This decrease results not only from the classical anomeric effect but also from the σ(CC) and σ(CN) → σ*(CH) delocalisation in the heteroaromatic ring.

  7. Spectroscopic studies on the binding interaction of novel 13-phenylalkyl analogs of the natural alkaloid berberine to nucleic acid triplexes.

    PubMed

    Bhowmik, Debipreeta; Buzzetti, Franco; Fiorillo, Gaetano; Lombardi, Paolo; Suresh Kumar, Gopinatha

    2014-01-01

    In this study we have characterized the capability of six 13-phenylalkyl analogs of berberine to stabilize nucleic acid triplex structures, poly(rA)⋅2poly(rU) and poly(dA)⋅2poly(dT). Berberine analogs bind to the RNA and DNA triplexes non-cooperatively. As the chain length of the substitution increased beyond CH2, the affinity enhanced up to critical length of (CH2)4, there after which the binding affinity decreased for both the triplexes. A remarkably stronger intercalative binding of the analogs compared to berberine to the triplexes was confirmed from ferrocyanide fluorescence quenching, fluorescence polarization and viscosity results. Circular dichroism results had indicated strong conformational changes in the triplexes on binding of the analogs. The analogs enhanced the stability of the Hoogsteen base paired third strand of both the triplexes while no significant change in the high-temperature duplex-to-single strand transitions was observed. Energetics of the interaction revealed that as the alkyl chain length increased, the binding was more entropy driven. This study demonstrates that phenylalkyl substitution at the 13-position of berberine increased the triplex binding affinity of berberine but a threshold length of the side chain is critical for the strong intercalative binding to occur.

  8. Ecological interactions and the fitness effect of water-use efficiency: Competition and drought alter the impact of natural MPK12 alleles in Arabidopsis.

    PubMed

    Campitelli, Brandon E; Des Marais, David L; Juenger, Thomas E

    2016-04-01

    The presence of substantial genetic variation for water-use efficiency (WUE) suggests that natural selection plays a role in maintaining alleles that affect WUE. Soil water deficit can reduce plant survival, and is likely to impose selection to increase WUE, whereas competition for resources may select for decreased WUE to ensure water acquisition. We tested the fitness consequences of natural allelic variation in a single gene (MPK12) that influences WUE in Arabidopsis, using transgenic lines contrasting in MPK12 alleles, under four treatments; drought/competition, drought/no competition, well-watered/competition, well-watered/no competition. Results revealed an allele × environment interaction: Low WUE plants performed better in competition, resulting from increased resource consumption. Contrastingly, high WUE individuals performed better in no competition, irrespective of water availability, presumably from enhanced water conservation and nitrogen acquisition. Our findings suggest that selection can influence MPK12 evolution, and represents the first assessment of plant fitness resulting from natural allelic variation at a single locus affecting WUE.

  9. Use of Interactive Sessions and E-Learning in Teaching Anatomy to First-Year Optometry Students

    ERIC Educational Resources Information Center

    Choudhury, Bipasha; Gouldsborough, Ingrid; Gabriel, Stefan

    2010-01-01

    Students enrolled in the Optometry program at the University of Manchester are required to take a functional anatomy course during the first year of their studies. Low mean scores in the written examination of this unit for the past two academic years energized staff to rethink the teaching format. Interactive sessions lasting 20 minutes each were…

  10. Interaction of a dengue virus NS1-derived peptide with the inhibitory receptor KIR3DL1 on natural killer cells.

    PubMed

    Townsley, E; O'Connor, G; Cosgrove, C; Woda, M; Co, M; Thomas, S J; Kalayanarooj, S; Yoon, I-K; Nisalak, A; Srikiatkhachorn, A; Green, S; Stephens, H A F; Gostick, E; Price, D A; Carrington, M; Alter, G; McVicar, D W; Rothman, A L; Mathew, A

    2016-03-01

    Killer immunoglobulin-like receptors (KIRs) interact with human leucocyte antigen (HLA) class I ligands and play a key role in the regulation and activation of NK cells. The functional importance of KIR-HLA interactions has been demonstrated for a number of chronic viral infections, but to date only a few studies have been performed in the context of acute self-limited viral infections. During our investigation of CD8(+) T cell responses to a conserved HLA-B57-restricted epitope derived from dengue virus (DENV) non-structural protein-1 (NS1), we observed substantial binding of the tetrameric complex to non-T/non-B lymphocytes in peripheral blood mononuclear cells (PBMC) from a long-standing clinical cohort in Thailand. We confirmed binding of the NS1 tetramer to CD56(dim) NK cells, which are known to express KIRs. Using depletion studies and KIR-transfected cell lines, we demonstrated further that the NS1 tetramer bound the inhibitory receptor KIR3DL1. Phenotypical analysis of PBMC from HLA-B57(+) subjects with acute DENV infection revealed marked activation of NS1 tetramer-binding natural killer (NK) cells around the time of defervescence in subjects with severe dengue disease. Collectively, our findings indicate that subsets of NK cells are activated relatively late in the course of acute DENV illness and reveal a possible role for specific KIR-HLA interactions in the modulation of disease outcomes.

  11. Interacting composite fermions: Nature of the 4/5, 5/7, 6/7, and 6/17 fractional quantum Hall states

    NASA Astrophysics Data System (ADS)

    Balram, Ajit C.

    2016-10-01

    Numerical studies by Wójs, Yi, and Quinn have suggested that an unconventional fractional quantum Hall effect is plausible at filling factors ν =1 /3 and 1/5, provided the interparticle interaction has an unusual form for which the energy of two fermions in the relative angular momentum three channel dominates. The interaction between composite fermions in the second Λ level (composite fermion analog of the electronic Landau level) satisfies this property, and recent studies have supported unconventional fractional quantum Hall effect of composite fermions at ν*=4 /3 and 5 /3 , which manifests as fractional quantum Hall effect of electrons at ν =4 /11 , 4/13, 5/13, and 5/17. I investigate in this article the nature of the fractional quantum Hall states at ν =4 /5 , 5/7, 6/17, and 6/7, which correspond to composite fermions at ν*=4 /3 , 5/3, and 6/5, and find that all these fractional quantum Hall states are conventional. The underlying reason is that the interaction between composite fermions depends substantially on both the number and the direction of the vortices attached to the electrons. I also study in detail the states with different spin polarizations at 6/17 and 6/7 and predict the critical Zeeman energies for the spin phase transitions between them. I calculate the excitation gaps at 4/5, 5/7, 6/7, and 6/17 and compare them against recent experiments.

  12. Cell metal interactions: A comparison of natural uranium to other common metals in renal cells and bone osteoblasts

    NASA Astrophysics Data System (ADS)

    Milgram, S.; Carrière, M.; Thiebault, C.; Berger, P.; Khodja, H.; Gouget, B.

    2007-07-01

    Uranium acute intoxication has been documented to induce nephrotoxicity. Kidneys are the main target organs after short term exposures to high concentrations of the toxic, while chronic exposures lead to its accumulation in the skeleton. In this paper, chemical toxicity of uranium is investigated for rat osteoblastic bone cells and compared to results previously obtained on renal cells. We show that bone cells are less sensitive to uranium than renal cells. The influence of the chemical form on U cytotoxicity is demonstrated. For both cell types, a comparison of uranium toxicity with other metals or metalloids toxicities (Mn, Ni, Co, Cu, Zn, Se and Cd) permits classification of Cd, Zn, Se IV and Cu as the most toxic and Ni, Se VI, Mn and U as the least toxic. Chemical toxicity of natural uranium proves to be far less than that of cadmium. To try to explain the differences in sensitivities observed between metals and different cell types, cellular accumulations in cell monolayers are quantified by inductively coupled plasma-mass spectroscopy (ICP-MS), function of time or function of dose: lethal doses which simulate acute intoxications and sub-lethal doses which are more realistic with regard to environmentally metals concentrations. In addition to being more resistant, bone cells accumulated much more uranium than did renal cells. Moreover, for both cell models, Mn, U-citrate and U-bicarbonate are strongly accumulated whereas Cu, Zn and Ni are weakly accumulated. On the other hand, a strong difference in Cd behaviour between the two cell types is shown: whereas Cd is very weakly accumulated in bone cells, it is very strongly accumulated in renal cells. Finally, elemental distribution of the toxics is determined on a cellular scale using nuclear microprobe analysis. For both renal and osteoblastic cells, uranium was accumulated in as intracellular precipitates similar to those observed previously by SEM/EDS.

  13. Structural energetics of protein–carbohydrate interactions: Insights derived from the study of lysozyme binding to its natural saccharide inhibitors

    PubMed Central

    García-Hernández, Enrique; Zubillaga, Rafael A.; Chavelas-Adame, Eneas A.; Vázquez-Contreras, Edgar; Rojo-Domínguez, Arturo; Costas, Miguel

    2003-01-01

    High-sensitivity isothermal titration calorimetry was used to characterize the binding of the glycohydrolitic enzyme hen egg-white lysozyme to its natural saccharide inhibitors, chitobiose and chitrotriose. Measurements were done at a pH of 4.7, in the 15°C –45°C temperature range. Using a structural-energetic parameterization derived previously for lectin-carbohydrate associations, both binding enthalpies and entropies for the present systems and for the complex of chitobiose with turkey egg-white lysozyme from the literature were correctly accounted for. These observations suggest that both lysozymes and lectins follow the same structural-energetic behavior in the binding to their ligands. From the analysis of lysozyme data in conjunction with other binding data reported in the literature, an ad hoc parameterization of ΔCp for protein–carbohydrate complexes was derived for the first time. The novel parameters for both polar and apolar surface areas differed significantly from correlations obtained previously from model compounds and protein-folding data. As ΔCp is extremely sensitive to changes in solvent structure, this finding indicates that protein–carbohydrate complexes have distinctive hydration properties. According to our analysis, the dehydration of polar groups is the major cause for the observed decrease in ΔCp, which implies that these groups behave hydrophobically. The contribution of apolar surface areas was found of the expected sign, but their specific weight is much smaller than those obtained in other correlations. This small contribution to ΔCp is consistent with Lemieux’s hypothesis of a low degree of hydration of apolar surfaces on carbohydrates. PMID:12493836

  14. The nature of peptide interactions with acid end-group PLGAs and facile aqueous-based microencapsulation of therapeutic peptides

    PubMed Central

    Sophocleous, Andreas M.; Desai, Kashappa-Goud H.; Mazzara, J. Maxwell; Tong, Ling; Cheng, Ji-Xin; Olsen, Karl F.; Schwendeman, Steven P.

    2013-01-01

    An important poorly understood phenomenon in controlled-release depots involves the strong interaction between common cationic peptides and low Mw free acid end-group poly(lactic-co-glycolic acids) (PLGAs) used to achieve continuous peptide release kinetics. The kinetics of peptide sorption to PLGA was examined by incubating peptide solutions of 0.2-4 mM octreotide or leuprolide acetate salts in 0.1 M HEPES buffer, pH 7.4, with polymer particles or films at 4-37 °C for 24 h. The extent of absorption/loading of peptides in PLGA particles/films was assayed by two-phase extraction and amino acid analysis. Confocal Raman microspectroscopy and stimulated Raman scattering (SRS) and laser scanning confocal imaging techniques were used to examine peptide penetration in the polymer phase. The release of sorbed peptide from leuprolide-PLGA particles was evaluated both in vitro (PBST + 0.02% sodium azide, 37 °C) and in vivo (male Sprague-Dawley rats). We found that when the PLGA-COOH chains are sufficiently mobilized, therapeutic peptides not only bind at the surface, a common belief to date, but can also internalized and distributed throughout the polymer phase at physiological temperature forming a salt with low-molecular weight PLGA-COOH. Importantly, absorption of leuprolide into low MW PLGA-COOH particles yielded ~17 wt% leuprolide loading in the polymer (i.e., ~70% of PLGA-COOH acids occupied), and the absorbed peptide was released from the polymer for > 2 weeks in a controlled fashion in vitro and as indicated by sustained testosterone suppression in male Sprague-Dawley rats. This new approach, which bypasses the traditional encapsulation method and associated production cost, opens up the potential for facile production of low-cost controlled-release injectable depots for leuprolide and related peptides. PMID:24021356

  15. Rethinking quasispecies theory: From fittest type to cooperative consortia.

    PubMed

    Villarreal, Luis P; Witzany, Guenther

    2013-11-26

    Recent investigations surprisingly indicate that single RNA "stem-loops" operate solely by chemical laws that act without selective forces, and in contrast, self-ligated consortia of RNA stem-loops operate by biological selection. To understand consortial RNA selection, the concept of single quasi-species and its mutant spectra as drivers of RNA variation and evolution is rethought here. Instead, we evaluate the current RNA world scenario in which consortia of cooperating RNA stem-loops (not individuals) are the basic players. We thus redefine quasispecies as RNA quasispecies consortia (qs-c) and argue that it has essential behavioral motifs that are relevant to the inherent variation, evolution and diversity in biology. We propose that qs-c is an especially innovative force. We apply qs-c thinking to RNA stem-loops and evaluate how it yields altered bulges and loops in the stem-loop regions, not as errors, but as a natural capability to generate diversity. This basic competence-not error-opens a variety of combinatorial possibilities which may alter and create new biological interactions, identities and newly emerged self identity (immunity) functions. Thus RNA stem-loops typically operate as cooperative modules, like members of social groups. From such qs-c of stem-loop groups we can trace a variety of RNA secondary structures such as ribozymes, viroids, viruses, mobile genetic elements as abundant infection derived agents that provide the stem-loop societies of small and long non-coding RNAs.

  16. Robustness and evolvability in natural chemical resistance: identification of novel systems properties, biochemical mechanisms and regulatory interactions.

    PubMed

    Venancio, Thiago M; Balaji, S; Geetha, S; Aravind, L

    2010-08-01

    A vast amount of data on the natural resistance of Saccharomyces cerevisiae to a diverse array of chemicals has been generated over the past decade (chemical genetics). We endeavored to use this data to better characterize the "systems" level properties of this phenomenon. By collating data from over 30 different genome-scale studies on growth of gene deletion mutants in presence of diverse chemicals, we assembled the largest currently available gene-chemical network. We also derived a second gene-gene network that links genes with significantly overlapping chemical-genetic profiles. We analyzed properties of these networks and investigated their significance by overlaying various sources of information, such as presence of TATA boxes in their promoters (which typically correlate with transcriptional noise), association with TFIID or SAGA, and propensity to function as phenotypic capacitors. We further combined these networks with ubiquitin and protein kinase-substrate networks to understand chemical tolerance in the context of major post-translational regulatory processes. Hubs in the gene-chemical network (multidrug resistance genes) are notably enriched for phenotypic capacitors (buffers against phenotypic variation), suggesting the generality of these players in buffering mechanistically unrelated deleterious forces impinging on the cell. More strikingly, analysis of the gene-gene network derived from the gene-chemical network uncovered another set of genes that appear to function in providing chemical tolerance in a cooperative manner. These appear to be enriched in lineage-specific and rapidly diverging members that also show a corresponding tendency for SAGA-dependent regulation, evolutionary divergence and noisy expression patterns. This set represents a previously underappreciated component of the chemical response that enables cells to explore alternative survival strategies. Thus, systems robustness and evolvability are simultaneously active as general

  17. Natural resource management in a protected area of the Indian Himalayas: a modeling approach for anthropogenic interactions on ecosystem.

    PubMed

    Nautiyal, Sunil; Kaechele, Harald

    2009-06-01

    varied and most showed that the current trend within rural ecosystems has emerged because of the implementation of conservation policies/creation of national park and biosphere reserve (80%), followed by limitation (22%), climate (20%), population growth (7%), national economy (10%) and least by socioeconomic change (5%). The theoretical agent model developed here draws attention to agent/farmer behavior and land resource use for his livelihood in the temporal dimension. The current study would be helpful to introduce new approaches for the development of the methodological and theoretical aspects associated with the complex human and ecosystem interactions in the Himalayan mountains for sustainable landscape development.

  18. Q?rius: An innovative and new interactive educational space at the Smithsonian Institution's National Museum of Natural History, in Washington, D.C

    NASA Astrophysics Data System (ADS)

    Blankenbicker, R.

    2013-12-01

    The Fall of 2013 marks the opening of Q?rius ('curious'), a 10,000 square foot, interactive educational space at the Smithsonian Institution's National Museum of Natural History. Representing the 7 areas of the museum's research divisions, Q?rius includes a publicly accessible collection of over 6,000 natural history objects and multiple opportunities for visitors to engage themselves in natural history and the research conducted at the museum in various settings, including a lab, theater, and studio. A digital component to the space allows visitors to save parts of their experiences to a personal account, which they can later access remotely from their home or school. The space also serves as a tool for scientists to conduct outreach programs for museum visitors and for schools across the country through distance learning capabilities. Geology content for Q?rius was developed through collaboration between the Office of Education and Outreach and the Department of Mineral Sciences, as well as scientists and educators from outside agencies. Current experiences for the public include modeling plate tectonics and how they change rocks on small and large scales, identifying minerals in rocks, and using Earth to understand Martian geology. A school program adds the concept of drill cores and natural resources to the plate tectonics activity, which allows discussion about resource extraction. Developing experiences for Q?rius in all content areas took place over 2 phases; first, through taking prototypes into the museum exhibition halls to test with visitors through several iterations, and second in the new space, where all of the activities could be tested as a group and in the appropriate environment. By the time this abstract has been submitted, the official opening will not have occurred, though Q?rius will have been open for about 1 month by the time of the 2013 AGU annual conference, allowing us to further evaluate the development of the space.

  19. On the multiscale nature of soil moisture-temperature couplings: the role of seasonality, causation and non-linear feedbacks in land-atmosphere interactions (Invited)

    NASA Astrophysics Data System (ADS)

    Molini, A.; Casagrande, E.; Mueller, B.

    2013-12-01

    Land-Atmosphere (L-A) interactions, their strength and directionality, are one of the main sources of uncertainty in current climate modeling, with strong implications on the accurate assessment of future climate variability and climate change impacts. Beside from the scarcity of direct observations, major uncertainties derive from the inherent complexity and nonlinearity of these interactions, and from their multi-scale character. Statistical analysis of L-A couplings is traditionally based on linear correlation methods and metrics. However, these approaches are not designed to detect causal connections or non-linear couplings and they poorly perform in presence of non-stationarities. Additionally these methods assess L-A couplings essentially in the time domain, despite the fact that L-A dynamical drivers can act simultaneously over a wide range of different space and time scales. This talk explores the multi-scale nature of L-A interactions, through the example of soil moisture-temperature couplings and soil-moisture memory effects. In several regions of the world, soil moisture can have a dampening effect on temperature due to evaporative cooling. By using spectral decomposition techniques and both newly developed satellite based products and re-analysis, we analyze the contribution of different time scales to the build-up of global soil moisture-temperature coupling hot spots, addressing at the same time the role of seasonality, causation and non-linear feedbacks in land-atmosphere interactions. Finally we focus on the role of fine (sub-monthly) time scales and their interplay with the seasonal scales.

  20. Kinetic and thermodynamic studies of the interaction between activating and inhibitory Ly49 natural killer receptors and MHC class I molecules.

    PubMed

    Romasanta, Pablo N; Curto, Lucrecia M; Sarratea, María B; Noli Truant, Sofía; Antonoglou, María B; Fernández Lynch, María J; Delfino, José M; Mariuzza, Roy A; Fernández, Marisa M; Malchiodi, Emilio L

    2017-01-01

    Natural killer (NK) cells are lymphocytes of the innate immune system that eliminate virally infected or malignantly transformed cells. NK cell function is regulated by diverse surface receptors that are both activating and inhibitory. Among them, the homodimeric Ly49 receptors control NK cell cytotoxicity by sensing major histocompatibility complex class I molecules (MHC-I) on target cells. Although crystal structures have been reported for Ly49/MHC-I complexes, the underlying binding mechanism has not been elucidated. Accordingly, we carried out thermodynamic and kinetic experiments on the interaction of four NK Ly49 receptors (Ly49G, Ly49H, Ly49I and Ly49P) with two MHC-I ligands (H-2D(d) and H-2D(k)). These Ly49s embrace the structural and functional diversity of the highly polymorphic Ly49 family. Combining surface plasmon resonance, fluorescence anisotropy and far-UV circular dichroism (CD), we determined that the best model to describe both inhibitory and activating Ly49/MHC-I interactions is one in which the two MHC-I binding sites of the Ly49 homodimer present similar binding constants for the two sites (∼10(6) M(-1)) with a slightly positive co-operativity in some cases, and without far-UV CD observable conformational changes. Furthermore, Ly49/MHC-I interactions are diffusion-controlled and enthalpy-driven. These features stand in marked contrast with the activation-controlled and entropy-driven interaction of Ly49s with the viral immunoevasin m157, which is characterized by strong positive co-operativity and conformational selection. These differences are explained by the distinct structures of Ly49/MHC-I and Ly49/m157 complexes. Moreover, they reflect the opposing roles of NK cells to rapidly scan for virally infected cells and of viruses to escape detection using immunoevasins such as m157.