Science.gov

Sample records for rethinking natural interactions

  1. Rethinking natural altruism: simple reciprocal interactions trigger children's benevolence.

    PubMed

    Cortes Barragan, Rodolfo; Dweck, Carol S

    2014-12-01

    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. 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

  3. Rethinking Terrestrial Pedagogy: Nature, Cultures, and Ethics

    ERIC Educational Resources Information Center

    Li, Huey-Li

    2006-01-01

    In this article, I offer a clarification of the ambiguities surrounding the pivotal concepts that have shaped and will continue to shape environmental education movement in the United States and beyond: nature, conservation, sustainable development, and environmental justice. I point out that dualistic frameworks not only polarize environmental…

  4. 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…

  5. 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…

  6. 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

  7. 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.

  8. Rethinking Natural Environment Practice: Implications from Examining Various Interpretations and Approaches

    ERIC Educational Resources Information Center

    Chai, Angie Y.; Zhang, Chun; Bisberg, Marilyn

    2006-01-01

    Early intervention professionals have implemented natural environment practices for over a decade, despite the continued debate on how to interpret and implement this practice. This article reviews several theoretical frameworks for understanding natural environment practice, and also summarizes different approaches for implementation. The authors…

  9. 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.

  10. 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…

  11. 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…

  12. "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…

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

    MedlinePlus

    ... 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 site. Tools to ...

  14. 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 ...

  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. Rethinking the nature of fibrolamellar bone: an integrative biological revision of sauropod plexiform bone formation.

    PubMed

    Stein, Koen; Prondvai, Edina

    2014-02-01

    We present novel findings on sauropod bone histology that cast doubt on general palaeohistological concepts concerning the true nature of woven bone in primary cortical bone and its role in the rapid growth and giant body sizes of sauropod dinosaurs. By preparing and investigating longitudinal thin sections of sauropod long bones, of which transverse thin sections were published previously, we found that the amount of woven bone in the primary complex has been largely overestimated. Using comparative cellular and light-extinction characteristics in the two section planes, we revealed that the majority of the bony lamina consists of longitudinally organized primary bone, whereas woven bone is usually represented only by a layer a few cells thin in the laminae. Previous arguments on sauropod biology, which have been based on the overestimated amount, misinterpreted formation process and misjudged role of woven bone in the plexiform bone formation of sauropod dinosaurs, are thereby rejected. To explain the observed pattern in fossil bones, we review the most recent advances in bone biology concerning bone formation processes at the cellular and tissue levels. Differentiation between static and dynamic osteogenesis (SO and DO) and the revealed characteristics of SO- versus DO-derived bone tissues shed light on several questions raised by our palaeohistological results and permit identification of these bone tissues in fossils with high confidence. By presenting the methods generally used for investigating fossil bones, we show that the major cause of overestimation of the amount of woven bone in previous palaeohistological studies is the almost exclusive usage of transverse sections. In these sections, cells and crystallites of the longitudinally organized primary bone are cut transversely, thus cells appear rounded and crystallites remain dark under crossed plane polarizers, thereby giving the false impression of woven bone. In order to avoid further confusion in

  17. 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…

  18. 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

  19. Interaction of pesticides with natural organic material

    USGS Publications Warehouse

    Wershaw, R. L.; Burcar, P.J.; Goldberg, M.C.

    1969-01-01

    Two examples of the interaction of pesticides with natural organic materials have been investigated. Sodium humate solubilizes DDT in water and humic acid strongly sorbs 2,4,5-T. These two types of interactions are indicative of the types that one would expect when any organic pesticide is applied to a natural soil-water system.

  20. Two Fundamental Principles of Nature's Interactions

    NASA Astrophysics Data System (ADS)

    Ma, Tian; Wang, Shouhong

    2014-03-01

    In this talk, we present two fundamental principles of nature's interactions, the principle of interaction dynamics (PID) and the principle of representation invariance (PRI). Intuitively, PID takes the variation of the action functional under energy-momentum conservation constraint. PID offers a completely different and natural way of introducing Higgs fields. PRI requires that physical laws be independent of representations of the gauge groups. These two principles give rise to a unified field model for four interactions, which can be naturally decoupled to study individual interactions. With these two principles, we are able to derive 1) a unified theory for dark matter and dark energy, 2) layered strong and weak interaction potentials, and 3) the energy levels of subatomic particles. Supported in part by NSF, ONR and Chinese NSF.

  1. Rethinking Resource Sharing

    ERIC Educational Resources Information Center

    Beaubien, Anne; Stevens, Patricia

    2008-01-01

    This article describes the need for rethinking resource sharing to offer both library users and nonlibrary users options to obtain the material they seek from both libraries and commerical sources. The article discusses several programs that are emerging including the "GoGetter" function, the Rethinking Resource Sharing Manifesto, user needs, and…

  2. 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.

  3. 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. PMID:25131402

  4. 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. PMID:24916453

  5. Gestures for natural interaction with video

    NASA Astrophysics Data System (ADS)

    Fourati, Nesrine; Marilly, Emmanuel

    2012-01-01

    In the context of immersive communications, we propose a method enabling natural video interactions through hand gesture recognition between users and a video meeting system. The interaction can be performed either by the mean of hand posture recognition or by the dynamic hand gesture recognition according to user's preference. The statistical approach adopted in our work to recognize hand posture has shown accurate results for both performance evaluation and user test. Besides, the combination of data-mining fields and signal processing for dynamic gestures recognition allows us to define the appropriate rules and to reduce the confusion between gestures. Furthermore, the hand region extraction is based on both skin color and background subtraction to avoid the detection of static objects that have a similar skin color. Finally, the collected user's feedback allows as to evaluate our approach from the user's point of view and to define the limitations that will be discussed in our perspectives in order to improve the results.

  6. 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. PMID:23070491

  7. 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

  8. Rethinking Roe.

    PubMed

    Scofield, G R

    1993-01-01

    This article maintains that when the US Supreme Court chose to decide Roe vs. Wade based on the concepts of privacy and personhood, it made a mistake that has crippled the approach to the problems raised by abortion. The Court opened itself to immediate challenge by ruling that a fetus is not a person and that a woman's right to abortion is tied to fetal viability. This approach has been further compromised by advances in medical technology which have substantially increased fetal viability. While one problem with insisting upon the right to privacy is that the Constitution fails to mention the concept, the real question about privacy concerns the nature of the relationship which should exist between the individual and the state. When pro-life forces voice an intention to eradicate privacy, they (perhaps unwittingly) play into the hands of those who view privacy as an impediment to the government's ability to assert itself in individual lives. The use of this concept to justify abortion leaves people wondering why privacy rather than life has anything to do with abortion. Just because the Roe decision is flawed, however, does not imply that it must or should be overturned. Roe was not wrongly decided, it was simply poorly decided, and both Roe and its opponents attempt to deny that the Court faced a tragic choice that implicates essential values which can not be decided in absolute terms. In order to reach a solution that demonstrates a respect for life and liberty, we must look beyond these concepts to that of equity. When considering rape, incest, and even contraception and the pursuit of motherhood, it is easy to see that we are a long way from equalizing sexual relations between men and women. The equity approach opens a much broader view of what abortion is really about, which is the status and role of women in society. While Roe has polarized women, centering the debate on a belief in equity may have generated solidarity and consensus around that principle

  9. NICA: Natural Interaction with a Caring Agent

    NASA Astrophysics Data System (ADS)

    de Carolis, Berardina; Mazzotta, Irene; Novielli, Nicole

    Ambient Intelligence solutions may provide a great opportunity for elderly people to live longer at home. Assistance and care are delegated to the intelligence embedded in the environment. However, besides considering service-oriented response to the user needs, the assistance has to take into account the establishment of social relations. We propose the use of a robot NICA (as the name of the project Natural Interaction with a Caring Agent) acting as a caring assistant that provides a social interface with the smart home services. In this paper, we introduce the general architecture of the robot's "mind" and then we focus on the need to properly react to affective and socially oriented situations.

  10. 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

  11. 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. This book…

  12. Rethinking TV History.

    ERIC Educational Resources Information Center

    Gomery, Douglas

    1997-01-01

    Proposes a rethinking of historical analysis of U. S. television history, to begin at the local level. Offers a case study of the place of Washington, DC, as a site for network news. Notes that, as a community, Washington presents an important site where forces such as migration and suburbanization shaped the early history of television. (SR)

  13. 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)

  14. 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…

  15. 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…

  16. The role of magnetic interactions in natural systems

    NASA Astrophysics Data System (ADS)

    Muxworthy, Adrian

    2013-04-01

    Inter-particle magnetic interactions between crystals in natural systems strongly affect their magnetic response. In the Bullerwell Lecture 2011, Adrian Muxworthy discusses how these interactions affect our ability to recover from rocks information about the ancient geomagnetic field behaviour, plate tectonics and palaeogeography, and how magnetotactic bacteria utilize interactions to improve navigational efficiency.

  17. 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.

  18. Analyzing Acoustic Interactions in Natural Bullfrog Choruses

    PubMed Central

    Simmons, Andrea Megela; Simmons, James A.; Bates, Mary E.

    2008-01-01

    Analysis of acoustic interactions between animals in active choruses is complex because of the large numbers of individuals present, their high calling rates, and the considerable numbers of vocalizations that either overlap or show close temporal alternation. The authors describe a methodology for recording chorus activity in bullfrogs (Rana catesbeiana) using multiple, closely-spaced acoustic sensors that provide simultaneous estimates of sound direction and sound characteristics. This method provides estimates of location of individual callers, even under conditions of call overlap. This is a useful technique for understanding the complexity of the acoustic scene faced by animals vocalizing in groups. PMID:18729655

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

    PubMed

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

    2013-04-01

    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

  20. 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

  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. PMID:15880766

  2. 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

  3. 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…

  4. Rethinking resilience from indigenous perspectives.

    PubMed

    Kirmayer, Laurence J; Dandeneau, Stéphane; Marshall, Elizabeth; Phillips, Morgan Kahentonni; Williamson, Karla Jessen

    2011-02-01

    The notions of resilience that have emerged in developmental psychology and psychiatry in recent years require systematic rethinking to address the distinctive cultures, geographic and social settings, and histories of adversity of indigenous peoples. In Canada, the overriding social realities of indigenous peoples include their historical rootedness to a specific place (with traditional lands, communities, and transactions with the environment) and the profound displacements caused by colonization and subsequent loss of autonomy, political oppression, and bureaucratic control. We report observations from an ongoing collaborative project on resilience in Inuit, Métis, Mi'kmaq, and Mohawk communities that suggests the value of incorporating indigenous constructs in resilience research. These constructs are expressed through specific stories and metaphors grounded in local culture and language; however, they can be framed more generally in terms of processes that include: regulating emotion and supporting adaptation through relational, ecocentric, and cosmocentric concepts of self and personhood; revisioning collective history in ways that valorize collective identity; revitalizing language and culture as resources for narrative self-fashioning, social positioning, and healing; and renewing individual and collective agency through political activism, empowerment, and reconciliation. Each of these sources of resilience can be understood in dynamic terms as emerging from interactions between individuals, their communities, and the larger regional, national, and global systems that locate and sustain indigenous agency and identity. This social-ecological view of resilience has important implications for mental health promotion, policy, and clinical practice. PMID:21333035

  5. Tuning inter-virus interactions in natural aquatic environments

    NASA Astrophysics Data System (ADS)

    Schmidt, Nathan W.; Udit, Andrew K.; Gutierrez, Leonardo; Nguyen; Finn, M. G.; Wong, Gerard C. L.

    2009-03-01

    Polymeric natural organic matter (NOM) originating from plants and animals is ubiquitous in natural aquatic environments. Many water-borne pathogens, including viruses, readily associate with NOM, which has a statistical distribution of charged and hydrophobic groups. Virus-NOM association influences the transport of viruses in groundwater environments, but little is known about this interaction, or how NOM can induce new inter-virus interactions. To better understand the interaction between NOM and aqueous contaminants, we use the MS2 and Qbeta viruses (diameters ˜ 27nm) as surrogate water-borne pathogens. Small Angle X-ray Scattering is used to characterize the inter-particle interaction between viruses over a range of NOM concentrations and different salt types and concentrations.

  6. 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.

  7. How Many Protein-Protein Interactions Types Exist in Nature?

    PubMed Central

    Mitra, Pralay; Zhang, Yang

    2012-01-01

    “Protein quaternary structure universe” refers to the ensemble of all protein-protein complexes across all organisms in nature. The number of quaternary folds thus corresponds to the number of ways proteins physically interact with other proteins. This study focuses on answering two basic questions: Whether the number of protein-protein interactions is limited and, if yes, how many different quaternary folds exist in nature. By all-to-all sequence and structure comparisons, we grouped the protein complexes in the protein data bank (PDB) into 3,629 families and 1,761 folds. A statistical model was introduced to obtain the quantitative relation between the numbers of quaternary families and quaternary folds in nature. The total number of possible protein-protein interactions was estimated around 4,000, which indicates that the current protein repository contains only 42% of quaternary folds in nature and a full coverage needs approximately a quarter century of experimental effort. The results have important implications to the protein complex structural modeling and the structure genomics of protein-protein interactions. PMID:22719985

  8. How many protein-protein interactions types exist in nature?

    PubMed

    Garma, Leonardo; Mukherjee, Srayanta; Mitra, Pralay; Zhang, Yang

    2012-01-01

    "Protein quaternary structure universe" refers to the ensemble of all protein-protein complexes across all organisms in nature. The number of quaternary folds thus corresponds to the number of ways proteins physically interact with other proteins. This study focuses on answering two basic questions: Whether the number of protein-protein interactions is limited and, if yes, how many different quaternary folds exist in nature. By all-to-all sequence and structure comparisons, we grouped the protein complexes in the protein data bank (PDB) into 3,629 families and 1,761 folds. A statistical model was introduced to obtain the quantitative relation between the numbers of quaternary families and quaternary folds in nature. The total number of possible protein-protein interactions was estimated around 4,000, which indicates that the current protein repository contains only 42% of quaternary folds in nature and a full coverage needs approximately a quarter century of experimental effort. The results have important implications to the protein complex structural modeling and the structure genomics of protein-protein interactions. PMID:22719985

  9. The Nature of Teacher-Child Interactions in Emotion Discourse

    ERIC Educational Resources Information Center

    Thomas, Dawn V.

    2010-01-01

    Emotions find their meanings within human relationships that permit emotions to be experienced, expressed, and explored. Social and emotional competence, marked by an understanding, expression, and control of emotion, is one of the hallmarks of emotional discourse--demonstrated in the very nature of interactive communication as individuals relate…

  10. 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.

  11. 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

  12. Query2Question: Translating Visualization Interaction into Natural Language.

    PubMed

    Nafari, Maryam; Weaver, Chris

    2015-06-01

    Richly interactive visualization tools are increasingly popular for data exploration and analysis in a wide variety of domains. Existing systems and techniques for recording provenance of interaction focus either on comprehensive automated recording of low-level interaction events or on idiosyncratic manual transcription of high-level analysis activities. In this paper, we present the architecture and translation design of a query-to-question (Q2Q) system that automatically records user interactions and presents them semantically using natural language (written English). Q2Q takes advantage of domain knowledge and uses natural language generation (NLG) techniques to translate and transcribe a progression of interactive visualization states into a visual log of styled text that complements and effectively extends the functionality of visualization tools. We present Q2Q as a means to support a cross-examination process in which questions rather than interactions are the focus of analytic reasoning and action. We describe the architecture and implementation of the Q2Q system, discuss key design factors and variations that effect question generation, and present several visualizations that incorporate Q2Q for analysis in a variety of knowledge domains. PMID:26357239

  13. The Nature of Intermolecular Interactions Between Aromatic Amino Acid Residues

    SciTech Connect

    Gervasio, Francesco; Chelli, Riccardo; Procacci, Piero; Schettino, Vincenzo

    2002-05-01

    The nature of intermolecular interactions between aromatic amino acid residues has been investigated by a combination of molecular dynamics and ab initio methods. The potential energy surface of various interacting pairs, including tryptophan, phenilalanine, and tyrosine, was scanned for determining all the relevant local minima by a combined molecular dynamics and conjugate gradient methodology with the AMBER force field. For each of these minima, single-point correlated ab initio calculations of the binding energy were performed. The agreement between empirical force field and ab initio binding energies of the minimum energy structures is excellent. Aromatic-aromatic interactions can be rationalized on the basis of electrostatic and van der Waals interactions, whereas charge transfer or polarization phenomena are small for all intermolecular complexes and, particularly, for stacked structures.

  14. Genetic Interactions Between Transcription Factors Cause Natural Variation in Yeast

    PubMed Central

    Gerke, Justin; Lorenz, Kim; Cohen, Barak

    2016-01-01

    Our understanding of the genetic basis of phenotypic diversity is limited by the paucity of examples in which multiple, interacting loci have been identified. We show that natural variation in the efficiency of sporulation, the program in yeast that initiates the sexual phase of the life cycle, between oak tree and vineyard strains is due to allelic variation between four nucleotide changes in three transcription factors: IME1, RME1, and RSF1. Furthermore, we identified that selection has shaped quantitative variation in yeast sporulation between strains. These results illustrate how genetic interactions between transcription factors are a major source of phenotypic diversity within species. PMID:19164747

  15. The Re-Think Tree.

    ERIC Educational Resources Information Center

    Gear, Jim

    1993-01-01

    The Re-Think Tree is a simple framework to help individuals assess and improve their behaviors related to environmental issues. The branches of the tree in order of priority are refuse, reduce, re-use, and recycle. Roots of the tree include such things as public opinion, education, and watchdog groups. (KS)

  16. 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,…

  17. 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…

  18. Does textual feedback hinder spoken interaction in natural language?

    PubMed

    Le Bigot, Ludovic; Terrier, Patrice; Jamet, Eric; Botherel, Valerie; Rouet, Jean-Francois

    2010-01-01

    The aim of the study was to determine the influence of textual feedback on the content and outcome of spoken interaction with a natural language dialogue system. More specifically, the assumption that textual feedback could disrupt spoken interaction was tested in a human-computer dialogue situation. In total, 48 adult participants, familiar with the system, had to find restaurants based on simple or difficult scenarios using a real natural language service system in a speech-only (phone), speech plus textual dialogue history (multimodal) or text-only (web) modality. The linguistic contents of the dialogues differed as a function of modality, but were similar whether the textual feedback was included in the spoken condition or not. These results add to burgeoning research efforts on multimodal feedback, in suggesting that textual feedback may have little or no detrimental effect on information searching with a real system. STATEMENT OF RELEVANCE: The results suggest that adding textual feedback to interfaces for human-computer dialogue could enhance spoken interaction rather than create interference. The literature currently suggests that adding textual feedback to tasks that depend on the visual sense benefits human-computer interaction. The addition of textual output when the spoken modality is heavily taxed by the task was investigated. PMID:20069480

  19. Nature of Amide Carbonyl−Carbonyl Interactions in Proteins

    PubMed Central

    2010-01-01

    Noncovalent interactions define and modulate biomolecular structure, function, and dynamics. In many protein secondary structures, an intimate interaction exists between adjacent carbonyl groups of the main-chain amide bonds. As this short contact contributes to the energetics of protein conformational stability as well as protein−ligand interactions, understanding its nature is crucial. The intimacy of the carbonyl groups could arise from a charge−charge or dipole−dipole interaction, or n→π * electronic delocalization. This last putative origin, which is reminiscent of the Bürgi−Dunitz trajectory, involves delocalization of the lone pairs (n) of the oxygen (Oi−1) of a peptide bond over the antibonding orbital (π*) of the carbonyl group (Ci=Oi) of the subsequent peptide bond. By installing isosteric chemical substituents in a peptidic model system and using NMR spectroscopy, X-ray diffraction analysis, and ab initio calculations to analyze the consequences, the intimate interaction between adjacent carbonyl groups is shown to arise primarily from n→π* electronic delocalization. This finding has implications for organic, biological, and medicinal chemistry. PMID:19469574

  20. 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…

  1. 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 Education" moves beyond a simplistic…

  2. 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.

  3. 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. PMID:26488560

  4. 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.

  5. Tubulin-Interactive Natural Products as Anticancer Agents1

    PubMed Central

    Kingston, David G. I.

    2009-01-01

    This review provides an overview of the discovery, structures, and biological activities of anticancer natural products which act by inhibiting or promoting the assembly of tubulin to microtubules. The emphasis is on providing recent information on those compounds in clinical use or in advanced clinical trials. The vinca alkaloids, the combretastatins, NPI-2358, the halichondrin B analog eribulin, dolastatin 10, noscapine, hemiasterlin, and rhizoxin are discussed as tubulin polymerization inhibitors, while the taxanes and the epothilones are the major classes of tubulin polymerization promoters presented, with brief treatments of discodermolide, eleutherobin, and laulimalide. The challenges and future directions of tubulin-interactive natural products-based drug discovery programs are also discussed briefly. PMID:19125622

  6. Effect Of Interaction On Apertures Of Multisegmented Natural Veins

    NASA Astrophysics Data System (ADS)

    Sim, Y.; Germanovich, L. N.; Vermilye, J. M.

    2003-12-01

    Echelons of multisegmented fluid-driven natural fractures (such as dikes, veins, and sometimes joints) with consecutive overlapping are one of the most common types of structures in the Earth­_s crust. The mechanical behavior of these fractures is quite different from that of single fractures, because of the interaction between the segments. In this work we compute the apertures of a highly segmented calcite vein, with 71 segments, in siltstone (Culpeper Quarry, Virginia) described by Vermilye and Scholz [1995]. The effect of elastic interaction between the segments is considered at three different special scales and accurately evaluated by solving the corresponding system of singular integral equations. For comparison, the case of ignored interaction is also considered. Our results unambiguously suggest that the effect of interaction highly affects the vein apertures. By using two net pressures in the vein as fitting parameters, it is possible to obtain an excellent match of the computed and measured apertures (based on 3,000 data points). This indicates two episodes in the history of vein evolution. Based on the performed simulation, a concept of effective fracture (vein) has been suggested. This is a single fracture of the same overall size (length) as the real vein. It is also pressurized by two net pressures that are determined by fitting the field data. As a result, practically the same net pressures are obtained as by accounting for the full interaction between the vein segments. The concept of effective fracture allows the sufficiently accurate computation of the vein (fracture) apertures, but without considering the interaction between the multiple segments.

  7. [The interactions between natural products and OATP1B1].

    PubMed

    Shi, Mei-zhi; Liu, Yu; Bian, Jia-lin; Jin, Meng; Gui, Chun-shan

    2015-07-01

    Organic anion transporting polypeptide 1B1 (OATP1B1) is an important liver-specific uptake transporter, which mediates transport of numerous endogenous substances and drugs from blood into hepatocytes. To identify and investigate potential modulators of OATP1B1 from natural products, the effect of 21 frequently used natural compounds and extracts on OATP1B1-mediated fluorescein methotrexate transport was studied by using Chinese hamster ovary cells stably expressing OATP1B1 (CHO-OATP1B1) in 96-well plates. This method could be used for the screening of large compound libraries. Our studies showed that some flavonoids (e.g., quercetin, quercitrin, rutin, chrysanthemum flavonoids and mulberrin) and triterpenoids (e.g., glycyrrhetinic acid and glycyrrhizic acid) were inhibitors of OATP1B1 with IC50 values less than 16 µmol · L(-1). The IC50 value of glycyrrhetinic acid on OATP1B1 was comparable to its blood concentration in clinics, indicating an OATPlB1-mediated drug-drug interaction could occur. Structure-activity relationship analysis showed that flavonoids had much higher inhibitory activity than their glycosides. Furthermore, the type and length of saccharides had a significant effect on their activity. In addition, we used OATP1B1 substrates fluvastatin and rosuvastatin as probe drugs to investigate the substrate-dependent effect of several natural compounds on the function of OATP1B1 in vitro. Our results demonstrated that the effect of these natural products on the function of OATPlB1 was substrate-dependent. In summary, this study would be conducive to predicting and avoiding potential OATP1B1-mediated drug-drug and drug-food interactions and thus provide the experimental basis and guidance for rational drug use. PMID:26552146

  8. 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…

  9. Interaction between manufactured gold nanoparticles and naturally occurring organic macromolecules.

    PubMed

    Diegoli, Sara; Manciulea, Adriana L; Begum, Shakiela; Jones, Ian P; Lead, Jamie R; Preece, Jon A

    2008-08-25

    The increasing exploitation of nanomaterials into many consumer and other products is raising concerns as these nanomaterials are likely to be released into the environment. Due to our lack of knowledge about the environmental chemistry, transport and ecotoxicology of nanomaterials, it is of paramount importance to study how natural aquatic colloids can interact with manufactured gold nanoparticles as these interactions will determine their environmental fate and behaviour. In this context, our work aims to quantify the effect of naturally occurring riverine macromolecules--International Humic Substances Society (IHSS) Suwannee River Humic Acid Standard (SRHA)--on citrate- and acrylate-stabilized gold nanoparticles. The influence of SRHA on the stability of the gold colloids was studied as a function of pH by UV-visible absorption spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). At high ionic strengths (0.1 M), extensive and rapid aggregation occurred, while more subtle effects were observed at lower ionic strength values. Evidence was found that SRHA enhances particle stability at extreme pH values (ionic strength<0.01 M) by substituting and/or over-coating the original stabilizer on the gold nanoparticle surface, thus affecting surface charge and chemistry. These findings have important implications for the fate and behaviour of nanoparticles in the environment and their ecotoxicity. PMID:18534664

  10. 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.

  11. Fungal ABC transporters and microbial interactions in natural environments.

    PubMed

    Schoonbeek, Henk-jan; Raaijmakers, Jos M; De Waard, Maarten A

    2002-11-01

    In natural environments, microorganisms are exposed to a wide variety of antibiotic compounds produced by competing organisms. Target organisms have evolved various mechanisms of natural resistance to these metabolites. In this study, the role of ATP-binding cassette (ABC) transporters in interactions between the plant-pathogenic fungus Botrytis cinerea and antibiotic-producing Pseudomonas bacteria was investigated in detail. We discovered that 2,4-diacetylphloroglucinol, phenazine-1-carboxylic acid and phenazine-1-carboxamide (PCN), broad-spectrum antibiotics produced by Pseudomonas spp., induced expression of several ABC transporter genes in B. cinerea. Phenazines strongly induced expression of BcatrB, and deltaBcatrB mutants were significantly more sensitive to these antibiotics than their parental strain. Treatment of B. cinerea germlings with PCN strongly affected the accumulation of [14C]fludioxonil, a phenylpyrrole fungicide known to be transported by BcatrB, indicating that phenazines also are transported by BcatrB. Pseudomonas strains producing phenazines displayed a stronger antagonistic activity in vitro toward ABcatrB mutants than to the parental B. cinerea strain. On tomato leaves, phenazine-producing Pseudomonas strains were significantly more effective in reducing gray mold symptoms incited by a ABcatrB mutant than by the parental strain. We conclude that the ABC transporter BcatrB provides protection to B. cinerea in phenazine-mediated interactions with Pseudomonas spp. Collectively, these results indicate that fungal ABC transporters can play an important role in antibiotic-mediated interactions between bacteria and fungi in plant-associated environments. The implications of these findings for the implementation and sustainability of crop protection by antagonistic microorganisms are discussed. PMID:12423022

  12. Use of interactive immersive visualization techniques for natural resources management

    NASA Astrophysics Data System (ADS)

    Bishop, Ian D.; Karadaglis, Chris

    1996-03-01

    Natural resources management typically requires prediction of environmental changes over long time periods. In the case of forest management, for example, decisions can affect timber production, water catchment properties, recreational values, aesthetic values, energy usage or employment opportunities. This paper presents an application of advanced visualization techniques in combination with a geographic information system and linear programming in this context. The emphasis is on provision of visual feedback on the outcome of decision options. This main interactive window include a 3D view of the management area based initially on remote sensing imagery draped on a digital terrain model. Also on screen are a slider for time (from the present to 200 years hence), and sliders for decision variables such as required job support level, extent of habit conservation or catchment performance. As the time, or the decision variables are altered by the user the result is presented through replacement of textures in the 3D view to represent the changes in land cover. Initially the visualization is based on prior modeling in a well-defined decision space. The system reads model output in ARC/INFO export format while interactive visualization is based on the Silicon Graphics Performer Toolkit.

  13. 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.

  14. Rethinking Tree Planting.

    ERIC Educational Resources Information Center

    Kock, Henry

    1994-01-01

    This author contends that observing and understanding natural succession is far more valuable to students than memories of planting lonely seedlings in a schoolyard. An approach that provides a richer experience using an holistic approach to habitat restoration is explored. (LZ)

  15. 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…

  16. 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.

  17. 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).

  18. Rethinking Drinking | NIH MedlinePlus the Magazine

    MedlinePlus

    ... this page please turn JavaScript on. Feature: Rethinking Drinking Rethinking Drinking Past Issues / Spring 2014 Table of Contents Do ... samhsa.gov Do You Have a Problem with Drinking? Ever felt you should cut down on your ...

  19. 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)

  20. 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. PMID:23875678

  1. 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.

  2. 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

  3. 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

  4. 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 ...

  5. 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

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

    PubMed

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

    2014-07-01

    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

  7. 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

  8. Unraveling the nature of interaction between substituted phenol and amiodarone.

    PubMed

    Hassan, Walid M I; Abo Dena, Ahmed S

    2014-02-01

    A comprehensive study of the interaction between nitrophenols (π-acceptors) and amiodarone (AM) was performed using electronic absorption spectra. The key point is to clarify the erroneous interpretation of the interaction between nitrophenols and one of the basic organic drugs. Matching of the experimental UV-vis spectra and the theoretical ones obtained by DFT calculations revealed that the tertiary amino group of AM reacts with the phenol compounds under investigation via proton-transfer but not charge-transfer (C.T.) mechanisms, unlike what is commonly known about this type of interaction. The interaction was carried out in solutions of different basic pH values to study the effect of hydrogen ion concentration on the reaction. The results show that the reaction is a simple acid-base reaction. As a result, this reaction cannot be used by analytical chemists for determination of one of the studied compounds due to its very low selectivity. TD-DFT as well as geometry optimization of the nitrophenols were calculated with the B3LYP functional, using aug-cc-pvDZ and LanL2DZ as basis sets for ionic and neutral compounds, respectively. The theoretical spectra of possible interactions between AM and nitrophenols result in the same spectra of ionized nitrophenols alone, indicating no possibility for the formation of charge-transfer complexes. PMID:24428617

  9. Interactions between Natural Health Products and Oral Anticoagulants: Spontaneous Reports in the Italian Surveillance System of Natural Health Products

    PubMed Central

    Paoletti, Angelica; Gallo, Eugenia; Benemei, Silvia; Vietri, Michele; Lapi, Francesco; Volpi, Roberta; Menniti-Ippolito, Francesca; Gori, Luigi; Mugelli, Alessandro; Firenzuoli, Fabio; Vannacci, Alfredo

    2011-01-01

    Introduction. The safety of vitamin K antagonists (VKA) use can be compromised by many popular herbal supplements taken by individuals. The literature reports that 30% of warfarin-treated patients self-medicates with herbs. Possible interactions represent an health risk. We aimed to identify all herbs-oral anticoagulants interactions collected in the Italian database of suspected adverse reactions to “natural health” products. Methods. The Italian database of spontaneous reports of suspected adverse reactions to natural products was analyzed to address herb-VKAs interactions. Results. From 2002 to 2009, we identified 12 reports with 7 cases of INR reduction in patients treated with warfarin (n = 3) and acenocoumarol (n = 4), and 5 cases of INR increase (all warfarin associated). It was reported 8 different herbal products as possibly interacting. Discussion. Our study confirms the risk of interactions, highlighting the difficulty to characterize them and their mechanisms and, finally, prevent their onset. The reported data underline the urgent need of healthcare providers being aware of the possible interaction between natural products and VKA, also because of the critical clinical conditions affecting patients. This is the first step to have the best approach to understand possible INR alterations linked to herb-VKA interaction and to rightly educate patients in treatment with VKA. PMID:21274401

  10. Covalent interaction of ascorbic acid with natural products

    PubMed Central

    Kesinger, Nicholas G.; Stevens, Jan F.

    2009-01-01

    While ascorbic acid (Vitamin C) is mostly known as a cofactor for proline hydroxylase and as a biological antioxidant, it also forms covalent bonds with natural products which we here refer to as ‘ascorbylation’. A number of natural products containing an ascorbate moiety has been isolated and characterized from a variety of biological sources, ranging from marine algae to flowering plants. Most of these compounds are formed as a result of nucleophilic substitution or addition by ascorbate, e.g. the ascorbigens from Brassica species are ascorbylated indole derivatives. Some ascorbylated tannins appear to be formed from electrophilic addition to dehydroascorbic acid. There are also examples of annulations of ascorbate with dietary polyphenols, e.g., epigallocatechin gallate (EGCG) and resveratrol derivatives. Herein is a survey of thirty-three ascorbylated natural products and their reported biological activities. PMID:19875138

  11. 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

  12. 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…

  13. 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...

  14. The nature of species interactions shifts profoundly between time periods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species interactions change through time, for example ontogenetically, successionally, and evolutionarily. They also change as environmental conditions change, both within years (seasonally) and between years (year effects). The former are relatively well-studied, but the latter have received less a...

  15. Nature of electron-lattice interaction in superconducting oxides

    SciTech Connect

    Egami, T.; Dmowski, W.; McQueeney, R.J.

    1994-12-31

    Various experimental results show that in high temperature superconducting oxides the lattice responds rather anomalously to the onset of superconductivity. This suggests that some unconventional electron-lattice interaction may be at work in these solids which could be important to the mechanism of high temperature superconductivity. The authors describe their recent experimental observations by neutron and X-ray scattering as well as some theoretical results which support this view, and discuss their implications.

  16. 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

  17. 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.

  18. 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. PMID:19249025

  19. 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.

  20. Wave-Current Interaction in a Natural Tidal Inlets

    NASA Astrophysics Data System (ADS)

    Moghimi, S.; Akan, C.; Özkan-Haller, H. T.

    2012-12-01

    The nearshore environment is characterized by complex hydrodynamics with high spatial and temporal variability, wave breaking, turbulence and other nonlinear processes. At a river mouth or an inlet, more complicated wave-current interaction processes and dynamics are involved. In this research we are intended to further develop and apply a dynamical coupled model system to the New River Inlet case. The modeling system consistent of a three-dimensional (3D) ocean model and a third generation spectral wind wave model to the above mentioned challenging environments. It seems even after inclusion of different physical processes (e.g. roller evolution, wave-current bottom boundary, wave enhanced eddy-viscosity) together with complicated mathematical methods (e.g. Vortex force (VF) formulation), there is still a lack of predictability compared to field observations. Here we also explore to what extent data assimilation techniques might be able to enhance the hydrodynamical modeling results and give a better understanding of the importance of different inputs parameters (e.g.bathymetry, surface roller).

  1. The temporary nature of number-space interactions.

    PubMed

    Fias, Wim; van Dijck, Jean-Philippe

    2016-03-01

    It is commonly accepted that the mental representation and processing of numbers and of space are tightly linked. This is evident from studies that have shown relations between math ability and visuospatial skill. Also, math instruction and education rely strongly on visuospatial tools and strategies. The dominant explanation for these number-space interactions is that the mental representation of numbers takes the form of a mental number line with numbers positioned in ascending order according to our reading habits. A long-standing debate is whether the link between numbers and space can be considered as evidence for a spatial number representation in long-term semantic memory, or whether this spatial frame is a temporary representation that emerges in working memory (WM) during task execution. We summarise our recent work that suggests basic number processing tasks do not operate on a long-term spatial memory representation, but on a representation constructed in serial order WM, where the elements are spatially coded as a function of their ordinal position in the memorised sequence. Implications for a new theoretical framework linking serial order WM and basic number processing are discussed. (PsycINFO Database Record PMID:26913783

  2. Infant Directed Speech in Natural Interaction--Norwegian Vowel Quantity and Quality

    ERIC Educational Resources Information Center

    Englund, Kjellrun T.; Behne, Dawn M.

    2005-01-01

    An interactive face-to-face setting is used to study natural infant directed speech (IDS) compared to adult directed speech (ADS). With distinctive vowel quantity and vowel quality, Norwegian IDS was used in a natural quasi-experimental design. Six Norwegian mothers were recorded over a period of 6 months alone with their infants and in an adult…

  3. Tasks, Teacher Feedback, and Learner Modified Output in Naturally Occurring Classroom Interaction

    ERIC Educational Resources Information Center

    Gurzynski-Weiss, Laura; Revesz, Andrea

    2012-01-01

    Tasks and interactional feedback have received much attention in instructed second language acquisition research in recent years. However, little research exists that has investigated feedback and task factors together during naturally occurring teacher-student interaction in classroom settings. To bridge this gap, the current study explored the…

  4. 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…

  5. Nature Utilizes Unusual High London Dispersion Interactions for Compact Membranes Composed of Molecular Ladders.

    PubMed

    Wagner, J Philipp; Schreiner, Peter R

    2014-03-11

    London dispersion interactions play a key role in nature, in particular, in membranes that constitute natural barriers. Here we demonstrate that the spatial alignment of "molecular ladders" ([n]ladderanes), i.e., highly unusual and strained all-trans-fused cyclobutane moieties, leads to much larger attractive dispersion interactions as compared to alkyl chains of the same length. This provides a rationale for the occurrence of peculiar ladderane fatty acids in the dense cell walls of anammox bacteria. Despite the energetic penalty paid for the assembly of such strained polycycles, the advantage lies in significantly higher, dispersion-dominated interaction energies as compared to straight-chain hydrocarbon moieties commonly found in fatty acids. We discern the dispersion contributions to the total interaction energies using a variety of computational methods including modern dispersion-corrected density functional theory and high level ab initio approaches. Utilizing larger assemblies, we also show that the intermolecular interactions behave additively. PMID:26580198

  6. An Investigation of the Nature and Form of Interactions in Live Interactive Television.

    ERIC Educational Resources Information Center

    Oliver, Ron; McLoughlin, Catherine

    Live interactive television (LIT) is a popular medium for delivering educational programs to students in remote areas in Australia. The medium uses television to deliver a live one-way video signal and standard telephony to provide two-way audio communication between the instructor and students. Much of the potential of this medium is derived from…

  7. 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.

  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. 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

  10. 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

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

    PubMed

    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- 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. PMID:27077844

  12. 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

  13. 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…

  14. 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…

  15. 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…

  16. 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…

  17. Radiative natural SUSY spectrum from deflected AMSB scenario with messenger-matter interactions

    NASA Astrophysics Data System (ADS)

    Wang, Fei; Yang, Jin Min; Zhang, Yang

    2016-04-01

    A radiative natural SUSY spectrum are proposed in the deflected anomaly mediation scenario with general messenger-matter interactions. Due to the contributions from the new interactions, positive slepton masses as well as a large | A t | term can naturally be obtained with either sign of deflection parameter and few messenger species (thus avoid the possible Landau pole problem). In this scenario, in contrast to the ordinary (radiative) natural SUSY scenario with under-abundance of dark matter (DM), the DM can be the mixed bino-higgsino and have the right relic density. The 125 GeV Higgs mass can also be easily obtained in our scenario. The majority of low EW fine tuning points can be covered by the XENON-1T direct detection experiments.

  18. 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. PMID:23689878

  19. 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

  20. Rethinking Piaget's Theory of Infancy.

    ERIC Educational Resources Information Center

    Smillie, David

    1982-01-01

    Drawing on Piaget's own work and some contemporary studies of social interaction, the author concludes that one may reinterpret Piaget's descriptive psychology in terms of the infant's growing communicative competency. (Author/MP)

  1. 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. PMID:27186603

  2. The Nature of the Noncovalent Interactions between Benzene and C60 Fullerene.

    PubMed

    Li, Ming-Ming; Wang, Yi-Bo; Zhang, Yu; Wang, Weizhou

    2016-07-21

    Noncovalent interactions between aromatic compounds and fullerenes have received considerable attention in various fields of science and technology. Employing benzene (C6H6) and C60 fullerene as model molecules, we theoretically explored in the present study the nature of this kind of noncovalent interaction. Our results clearly show that the π···π stacking configurations of the complex C6H6···C60 are more strongly bound than in the C-H···π analogues, and the C-H···π interactions in the C-H···π configurations of C6H6···C60 are not of the hydrogen bonds. According to symmetry adapted perturbation theory analyses, all of the configurations of C6H6···C60 are dominated by dispersion forces. The percentage of the dispersion components in the overall attractive interactions for the π···π stacking configurations is smaller than the percentage of the dispersion components in the overall attractive interactions for the C-H···π configurations, whereas the percentage of the electrostatic terms in the overall attractive interactions for the π···π stacking configurations is larger than the percentage of the electrostatic terms in the overall attractive interactions for the C-H···π configurations. This is distinctly different from the case of the benzene dimer. PMID:27366821

  3. Natural and orthogonal model for estimating gene-gene interactions applied to cutaneous melanoma.

    PubMed

    Xiao, Feifei; Ma, Jianzhong; Cai, Guoshuai; Fang, Shenying; Lee, Jeffrey E; Wei, Qingyi; Amos, Christopher I

    2014-05-01

    Epistasis, or gene-gene interaction, results from joint effects of genes on a trait; thus, the same alleles of one gene may display different genetic effects in different genetic backgrounds. In this study, we generalized the coding technique of a natural and orthogonal interaction (NOIA) model for association studies along with gene-gene interactions for dichotomous traits and human complex diseases. The NOIA model which has non-correlated estimators for genetic effects is important for estimating influence from multiple loci. We conducted simulations and data analyses to evaluate the performance of the NOIA model. Both simulation and real data analyses revealed that the NOIA statistical model had higher power for detecting main genetic effects and usually had higher power for some interaction effects than the usual model. Although associated genes have been identified for predisposing people to melanoma risk: HERC2 at 15q13.1, MC1R at 16q24.3 and CDKN2A at 9p21.3, no gene-gene interaction study has been fully explored for melanoma. By applying the NOIA statistical model to a genome-wide melanoma dataset, we confirmed the previously identified significantly associated genes and found potential regions at chromosomes 5 and 4 that may interact with the HERC2 and MC1R genes, respectively. Our study not only generalized the orthogonal NOIA model but also provided useful insights for understanding the influence of interactions on melanoma risk. PMID:24241239

  4. The nature of the interlayer interaction in bulk and few-layer phosphorus

    DOE PAGESBeta

    Shulenburger, Luke; Baczewski, A. D.; Zhu, Z.; Guan, J.; Tomanek, David

    2015-11-02

    Sensitive dependence of the electronic structure on the number of layers in few-layer phosphorene raises a question about the true nature of the interlayer interaction in so-called van der Waals (vdW) solids . We performed quantum Monte Carlo calculations and found that the interlayer interaction in bulk black phosphorus and related few-layer phosphorene is associated with a significant charge redistribution that is incompatible with purely dispersive forces and not captured by density functional theory calculations with different vdW corrected functionals. Lastly, these findings confirm the necessity of more sophisticated treatment of nonlocal electron correlation in total energy calculations.

  5. Using the Semi-Circular Bending Test to Investigate the Interaction Between Hydraulic and Natural Fractures

    NASA Astrophysics Data System (ADS)

    Wang, W.; Olson, J. E.; Prodanovic, M.

    2014-12-01

    Micro-seismic data shows that hydraulic fracture propagation is a complex process. When hydraulic fractures interact with pre-existing natural fractures, it can result in a complex fracture network. The interaction depends on in-situ stresses, rock and natural fracture mechanical properties, approach angle and hydraulic fracture treatment parameters. Most simulation studies treat natural fractures as frictional interfaces with cohesive properties. However, from core observation, partially cemented and fully cemented natural fractures are widely present and it is not clear that whether they fit the common description or not. In this study, semi-circular bending experiments are utilized to examine the fracture propagation paths. Synthetic hydrostone samples with embedded inclusions of different mechanical properties are used to mimic rock and cemented natural fractures. Simulation results are generated using finite element software ABAQUS. The extended finite element method (XFEM) capability of ABAQUS allows the fracture initiation and propagation along a solution dependent path without the need for re-meshing. The simulation results are used to explain the experimental observations. In a series of experiment and modeling work, we assess the influence of the fracture approach angle, inclusion strength, and inclusion thickness on fracture propagation. Current results indicate the fracture propagation direction is strongly influenced by pre-existing inclusions. The propagating fractures tend to cross the inclusion when the approach angle is high and divert into the inclusion when the approach angle is low. The crossing surface is thus not a clean cut, but with a jog distance that depends on the inclusion thickness and approach angle. Results imply that if hydraulic fractures have lower approach angles to pre-existing natural fractures, the ultimate fracture network is going to have higher complexity. The thickness of natural fractures can also add to the complexity.

  6. Rethinking the Tertiary Mathematics Curriculum

    ERIC Educational Resources Information Center

    Petocz, Peter; Reid, Anna

    2005-01-01

    Mathematics curriculum at the tertiary level is located within a range of social and cultural theories, and is often constructed by academics seeking to promulgate a particular view of mathematics. We argue that such a curriculum should incorporate a real acknowledgement of the different ways in which students understand the nature of mathematics…

  7. 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.

  8. Role of ATP-binding cassette (ABC) transporters in interactions between natural products and drugs.

    PubMed

    Aszalos, Adorjan

    2008-12-01

    Medicinal use of natural products such as extracts of plants has existed for many years in China and in other countries and they are now available worldwide. Citrus fruit juices are consumed on a daily basis around the world. Modern medicine provides well-tested compounds or drugs for most sicknesses. However, the simultaneous consumption of plant extracts, food supplements, and fruit juices with drugs can create metabolic aberrations in humans. Interactions between drugs used simultaneously are regulated by government agencies. Not regulated, but warned against in drug inserts are potential interactions between drugs and food and food-additives containing certain compounds with potential side effects. Summarized here are the results of investigations that point out possible interactions at the level of transporter molecules by drugs and compounds of natural origin. These transporter molecules play important roles in absorption in the intestines, at the blood brain barrier, in the liver, the kidney and in some other parts of the human body. Drugs and metabolites pass through these pumps and may compete with compounds from food supplements. The most studied natural compounds that are potential modulators of these transport molecules are flavonoids, found in fruit juices, vegetables, flowers and tea. Mycotoxins found in cereal grains are also shown to modulate transporter proteins. We detail here how such constituents of natural origin were shown to modulate three types of the major transporter molecules, P-glycoprotein (ABCB1), multidrug resistance proteins (ABCCs) and breast cancer resistance protein (ABCG2). Interference of these natural compounds with drugs at the transporter level is also discussed. PMID:19075617

  9. 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

  10. Ab initio no core configuration interaction calculations in the natural orbital basis

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

    The natural orbital basis has been successfully used in the past in atomic and molecular structure calculations. The natural orbitals used in those calculations are calculated by diagonalizing the electron one-body density matrix. Here we develop natural orbitals for nuclear no-core configuration interaction (NCCI) calculations. A NCCI calculation using an initial single particle basis, such as the harmonic oscillator basis, must first be performed in order to obtain a one-body density matrix. The eigenvectors of the one-body density matrix are the natural orbitals, and the corresponding eigenvalues are the occupations of these natural orbitals in the nuclear wave function. According to these occupancies, the most important natural orbitals, in the sense of the most occupied, can then be selected and used in a NCCI calculation. We discuss ab initio nuclear NCCI calculations for light nuclei and assess their ability to provide faster convergence. Supported by the US DOE (under Grants DE-FG02-95ER-40934, DESC0008485 SciDAC/NUCLEI, and DE-FG02-87ER40371), and the US NSF (under Grant 0904782). Computational resources provided by NERSC (supported by US DOE Contract DE-AC02-05CH11231), and NDCRC.

  11. Interactions of bovine and caprine herpesviruses with the natural and the foreign hosts.

    PubMed

    Engels, M; Palatini, M; Metzler, A E; Probst, U; Kihm, U; Ackermann, M

    1992-11-01

    Bovine herpesvirus 1 (BHV1) and caprine herpesvirus 1 (CapHV1) are useful models to study virus-host interactions, as well as pathogenicity and latency, when comparing the outcome of infection in the natural and the foreign hosts. Molecular seroepidemiological analyses revealed that cross-reacting antibodies were mainly induced by glycoprotein gI (gB analogue), by the major capsid protein and by nonstructural proteins, whereas the most virus-specific antibodies were elicited by glycoproteins gIII and gIV. These glycoproteins, especially gIII (gC analogue), might therefore play an important role in the virus-host-interactions. As a basis for further studies, we re-evaluated observations concerning experimental infections with BHV1 and CapHV1 in the natural and the foreign hosts. All parameters indicated that both viruses were able to infect either host, but that the pathogenicity was restricted to the natural host. Latent virus could be reactivated exclusively from cows infected with BHV1. It was possible neither to reactivate BHV1 from goats, nor to reactivate CapHV1 from either species. The experiments indicated that the outcome of infection in the natural and the foreign host is dependent on host and viral factors, whereby gIII is only one important virus component involved. Further investigations in the host and host cell range of BHV1 and CapHV1 will help to clarify the role of factors responsible for virus-host-interactions. PMID:1336252

  12. 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

  13. 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

  14. [Interaction of human alpha-thrombin with organic ligands of ionic nature].

    PubMed

    Kolodzeĭskaia, M V; Chumachenko, Iu V; Volkov, G L

    2003-01-01

    Investigations results of human thrombin interaction with organic ligands of ion nature containing nonpolar groups are presented. It is shown that electrostatic interaction is the basic one under enzyme binding, while hydrophobic binding is only additional function in the reaction enzyme-ligand, this fact is confirmed by the absence of interaction between thrombin and rivanol which has a positive charge side by side with cumbrous hydrophobic group. New data are presented about the ligand specificity of binding sites of thrombin active centre. The importance of relative arrangement of hydrophobic ligand groups for interaction with enzyme is shown. It is supposed that thrombin binding with organic ligands occurs owing anionic site of beta-domain of active thrombin centre with the major aminoacids arginine and lysine (Lys 68, Arg 78, Arg 77, Arg 66 etc.). It is shown that the compounds containing negative group SO3 and have some cunbours hydrophobic groups interact more intensively with the enzyme. Thus, rosseline--with symmetrical hydrophobic nucleus (four benzene rings)--is the most efficient ligand for the binding with thrombin. The obtained investigation results evidence for bacteriostatical and stabilizing effect of low-molecular asobenzene ligands on rather labile thrombin molecules. PMID:15143519

  15. 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.

  16. Asymmetrical nature of the Trollius-Chiastocheta interaction: insights into the evolution of nursery pollination systems.

    PubMed

    Suchan, Tomasz; Beauverd, Mélanie; Trim, Naïké; Alvarez, Nadir

    2015-11-01

    The mutualistic versus antagonistic nature of an interaction is defined by costs and benefits of each partner, which may vary depending on the environment. Contrasting with this dynamic view, several pollination interactions are considered as strictly obligate and mutualistic. Here, we focus on the interaction between Trollius europaeus and Chiastocheta flies, considered as a specialized and obligate nursery pollination system - the flies are thought to be exclusive pollinators of the plant and their larvae develop only in T. europaeus fruits. In this system, features such as the globelike flower shape are claimed to have evolved in a coevolutionary context. We examine the specificity of this pollination system and measure traits related to offspring fitness in isolated T. europaeus populations, in some of which Chiastocheta flies have gone extinct. We hypothesize that if this interaction is specific and obligate, the plant should experience dramatic drop in its relative fitness in the absence of Chiastocheta. Contrasting with this hypothesis, T. europaeus populations without flies demonstrate a similar relative fitness to those with the flies present, contradicting the putative obligatory nature of this pollination system. It also agrees with our observation that many other insects also visit and carry pollen among T. europaeus flowers. We propose that the interaction could have evolved through maximization of by-product benefits of the Chiastocheta visits, through the male flower function, and selection on floral traits by the most effective pollinator. We argue this mechanism is also central in the evolution of other nursery pollination systems. PMID:26640658

  17. Strength and nature of hydrogen bonding interactions in mono- and di-hydrated formamide complexes.

    PubMed

    Angelina, Emilio L; Peruchena, Nélida M

    2011-05-12

    In this work, mono- and di-hydrated complexes of the formamide were studied. The calculations were performed at the MP2/6-311++G(d,p) level of approximation. The atoms in molecules theory (AIM), based on the topological properties of the electronic density distribution, was used to characterize the different types of bonds. The analysis of the hydrogen bonds (H-bonds) in the most stable mono- and di-hydrated formamide complexes shows a mutual reinforcement of the interactions, and some of these complexes can be considered as "bifunctional hydrogen bonding hydration complexes". In addition, we analyzed how the strength and the nature of the interactions, in mono-hydrated complexes, are modified by the presence of a second water molecule in di-hydrated formamide complexes. Structural changes, cooperativity, and electron density redistributions demonstrate that the H-bonds are stronger in the di-hydrated complexes than in the corresponding mono-hydrated complexes, wherein the σ- and π-electron delocalization were found. To explain the nature of such interactions, we carried out the atoms in molecules theory in conjunction with reduced variational space self-consistent field (RVS) decomposition analysis. On the basis of the local Virial theorem, the characteristics of the local electron energy density components at the bond critical points (BCPs) (the 1/4∇ (2)ρ(b) component of electron energy density and the kinetic energy density) were analyzed. These parameters were used in conjunction with the electron density and the Laplacian of the electron density to analyze the characteristics of the interactions. The analysis of the interaction energy components for the systems considered indicates that the strengthening of the hydrogen bonds is manifested by an increased contribution of the electrostatic energy component represented by the kinetic energy density at the BCP. PMID:21506592

  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. PMID:24143939

  19. Pollinator Interactions with Yellow Starthistle (Centaurea solstitialis) across Urban, Agricultural, and Natural Landscapes

    PubMed Central

    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. PMID:24466050

  20. 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.

  1. 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.

  2. 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. PMID:16516292

  3. a Unified Perspective on the Nature of Pairwise Interatomic Interactions from Ar2 to Carbon Monoxide.

    NASA Astrophysics Data System (ADS)

    Rosales, Charles K.; Rivera-Rivera, Luis A.; McElmurry, Blake A.; Lucchese, Robert R.; Bevan, John W.; Walton, Jay R.

    2014-06-01

    A method is developed that gives a unified perspective on the nature of a wide range of pairwise interatomic interactions. The approach is applied to the diatomic molecules CO, H2+, H2, HF, LiH, Li2, O2, and Ar2, and one-dimensional cuts through the potentials of OC-HBr, OC-HF, OC-HCCH, OC-HCN, OC-HCl, OC-HI, OC-BrCl, and OC-Cl2. Systems selected for investigation illustrate different bound categories varying from van der Waals, halogen bonded, hydrogen bonded to strongly bound covalently bound carbon monoxide with binding energies varying over almost three orders of magnitude, from 99.3 wn to 90683 wn. Accurate semi-empirically determined Rydberg-Klein-Rees or morphed interatomic potentials are used in transformations for this wide range of species to a reduced potential demonstrating commonality in their fundamental nature.

  4. 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. PMID:26079802

  5. 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.

  6. The interaction of sexually and naturally selected traits in the adaptive radiations of cichlid fishes.

    PubMed

    Salzburger, Walter

    2009-01-01

    The question of how genetic variation translates into organismal diversity has puzzled biologists for decades. Despite recent advances in evolutionary and developmental genetics, the mechanisms that underlie adaptation, diversification and evolutionary innovation remain largely unknown. The exceptionally diverse species flocks of cichlid fishes are textbook examples of adaptive radiation and explosive speciation and emerge as powerful model systems to study the genetic basis of animal diversification. East Africa's hundreds of endemic cichlid species are akin to a natural mutagenesis screen and differ greatly not only in ecologically relevant (hence naturally selected) characters such as mouth morphology and body shape, but also in sexually selected traits such as coloration. One of the most fascinating aspects of cichlid evolution is the frequent occurrence of evolutionary parallelisms, which has led to the question whether selection alone is sufficient to produce these parallel morphologies, or whether a developmental or genetic bias has influenced the direction of diversification. Here, I review fitness-relevant traits that could be responsible for the cichlids' evolutionary success and assess whether these were shaped by sexual or natural selection. I then focus on the interaction and the relative importance of sexual vs. natural selection in cichlid evolution. Finally, I discuss what is currently known about the genes underlying the morphogenesis of adaptively relevant traits and highlight the importance of the forthcoming cichlid genomes in the quest of the genetic basis of diversification in this group. PMID:18992003

  7. 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.

  8. The nature of the hydrogen bond: A synthesis from the interacting quantum atoms picture

    NASA Astrophysics Data System (ADS)

    Martín Pendás, A.; Blanco, M. A.; Francisco, E.

    2006-11-01

    The interacting quantum atoms approach [IQA, as presented by Blanco et al., J. Chem. Theory Comput. 1, 1096 (2005)] is applied to standard hydrogen bonded dimers. IQA is an interpretation tool based on a real space energy decomposition scheme fully consistent with the quantum theory of atoms in molecules. It provides a partition of every physical term present in the Hamiltonian into atomic and interatomic contributions. The procedure is orbital-free and self-contained, needing neither external references nor artificial intermediate states. Binding is the result of a competition between the destabilizing deformations suffered by the interacting fragments upon interaction and the stabilizing interaction energy itself. According to IQA, there is no incompatibility between the prevalent electrostatic image of hydrogen bonded systems and that favoring important covalent contributions. Depending on how we gather the different energetic terms, we may recover electrostatic or covalent pictures from the same underlying quantum mechanical description. Our results show that the nonclassical contributions to hydrogen bonding are spatially localized, involving only the H atom and its two nearest neighbors. IQA is well suited as a comparative tool. Its thin energetic decomposition allows us to recover exactly (or to a very good approximation) the quantities of the most widely used energy decomposition schemes. Such a comparison sheds light on the virtues and faults of the different methods and on the origin of the 50years old debate regarding the covalent/electrostatic nature of the hydrogen bond.

  9. Molecular interaction of human brain acetylcholinesterase with a natural inhibitor huperzine-B: an enzoinformatics approach.

    PubMed

    Alam, Aftab; Shaikh, Sibhghatulla; Ahmad, Syed S; Ansari, Mohammad A; Shakil, Shahnawaz; Rizvi, Syed M D; Shakil, Shazi; Imran, Mohammad; Haneef, Mohammad; Abuzenadah, Adel M; Kamal, Mohammad A

    2014-04-01

    The present study emphasizes the molecular interactions between human brain acetylcholinesterase (AChE) and the natural ligand Huperzine-B and its comparison to 'AChE-Tolserine interactions'. Docking between Huperzine-B and AChE was performed using 'Autodock4.2'. Hydrophobic interactions and hydrogen bonds both play an equally important role in the correct positioning of Huperzine-B within the 'catalytic site' of AChE to permit docking. However, docking of Tolserine to AChE is largely dominated by hydrophobic interactions. Such information may aid in the design of versatile AChE-inhibitors, and is expected to aid in safe clinical use of Huperzine-B. Scope still remains in the determination of the three-dimensional structure of AChE-Huperzine-B complex by X-ray crystallography to validate the described data. Furthermore, this study confirms that Huperzine-B is a more efficient inhibitor of human brain AChE compared to tolserine with reference to Ki and ΔG values. PMID:24059299

  10. 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. PMID:26776752

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

    PubMed

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

    2009-04-01

    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. PMID:19714886

  12. QSAR modeling and molecular interaction analysis of natural compounds as potent neuraminidase inhibitors.

    PubMed

    Sun, Jiaying; Mei, Hu

    2016-04-26

    Different QSAR models of 40 natural compounds as neuraminidase inhibitors (NIs) are developed to comprehend chemical-biological interactions and predict activities against neuraminidase (NA) from Clostridium perfringens. Based on the constitutional, topological and conformational descriptors, R(2) and Q(2) values of the obtained SRA model are 0.931 and 0.856. The R(2) and Q(2) values of the constructed HQSAR and almond models are 0.903 and 0.767, 0.904 and 0.511, respectively. Based on the pharmacophore alignment, R(2) and Q(2) values of the optimal CoMSIA model are 0.936 and 0.654. Moreover, Rtest(2) and Qext(2) of values of SRA, HQSAR, almond and CoMSIA models are 0.611 and 0.565, 0.753 and 0.750, 0.612 and 0.582, 0.582 and 0.571, respectively. So, QSAR models have good predictive capability. They can be further used to evaluate and screen new compounds. Moreover, hydrogen bonds and electrostatic factors have high contributions to activities. To understand molecular interactions between natural compounds and NA from Clostridium perfringens, molecular docking is investigated. The docking results elucidate that Arg266, Asp291, Asp328, Tyr485, Glu493, Arg555, Arg615 and Tyr655 are especially the key residues in the active site of 2bf6. Hydrogen bonds and electrostatics are key factors, which impact the interactions between NIs and NA. So, the influential factors of interactions between NIs and NA in the docking results are in agreement with the QSAR results. PMID:27008437

  13. 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

  14. 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

  15. 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. PMID:26070840

  16. 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. PMID:25413866

  17. 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

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

    PubMed Central

    Gufford, Brandon T.; Chen, Gang; Vergara, Ana G.; Lazarus, Philip; Oberlies, Nicholas H.

    2015-01-01

    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. PMID:26070840

  19. Destructive Interactions Between Mitigation Strategies and the Causes of Unexpected Failures in Natural Hazard Mitigation Systems

    NASA Astrophysics Data System (ADS)

    Day, S. J.; Fearnley, C. J.

    2013-12-01

    Large investments in the mitigation of natural hazards, using a variety of technology-based mitigation strategies, have proven to be surprisingly ineffective in some recent natural disasters. These failures reveal a need for a systematic classification of mitigation strategies; an understanding of the scientific uncertainties that affect the effectiveness of such strategies; and an understanding of how the different types of strategy within an overall mitigation system interact destructively to reduce the effectiveness of the overall mitigation system. We classify mitigation strategies into permanent, responsive and anticipatory. Permanent mitigation strategies such as flood and tsunami defenses or land use restrictions, are both costly and 'brittle': when they malfunction they can increase mortality. Such strategies critically depend on the accuracy of the estimates of expected hazard intensity in the hazard assessments that underpin their design. Responsive mitigation strategies such as tsunami and lahar warning systems rely on capacities to detect and quantify the hazard source events and to transmit warnings fast enough to enable at risk populations to decide and act effectively. Self-warning and voluntary evacuation is also usually a responsive mitigation strategy. Uncertainty in the nature and magnitude of the detected hazard source event is often the key scientific obstacle to responsive mitigation; public understanding of both the hazard and the warnings, to enable decision making, can also be a critical obstacle. Anticipatory mitigation strategies use interpretation of precursors to hazard source events and are used widely in mitigation of volcanic hazards. Their critical limitations are due to uncertainties in time, space and magnitude relationships between precursors and hazard events. Examples of destructive interaction between different mitigation strategies are provided by the Tohoku 2011 earthquake and tsunami; recent earthquakes that have impacted

  20. 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...

  1. Genetic variations and miRNA-target interactions contribute to natural phenotypic variations in Populus.

    PubMed

    Chen, Jinhui; Xie, Jianbo; Chen, Beibei; Quan, Mingyang; Li, Ying; Li, Bailian; Zhang, Deqiang

    2016-10-01

    Variation in regulatory factors, including microRNAs (miRNAs), contributes to variation in quantitative and complex traits. However, in plants, variants in miRNAs and their target genes that contribute to natural phenotypic variation, and the underlying regulatory networks, remain poorly characterized. We investigated the associations and interactions of single-nucleotide polymorphisms (SNPs) in miRNAs and their target genes with phenotypes in 435 individuals from a natural population of Populus. We used RNA-seq to identify 217 miRNAs differentially expressed in a tension wood system, and identified 1196 candidate target genes; degradome sequencing confirmed 60 of the target sites. In addition, 72 miRNA-target pairs showed significant co-expression. Gene ontology (GO) term analysis showed that most of the genes in the co-regulated pairs participate in biological regulation. Genome resequencing found 5383 common SNPs (frequency ≥ 0.05) in 139 miRNAs and 31 037 SNPs in 819 target genes. Single-SNP association analyses identified 232 significant associations between wood traits (P ≤ 0.05) and SNPs in 102 miRNAs and 1387 associations with 478 target genes. Among these, 102 miRNA-target pairs associated with the same traits. Multi-SNP associations found 102 epistatic pairs associated with traits. Furthermore, a reconstructed regulatory network contained 12 significantly co-expressed pairs, including eight miRNAs and nine targets associated with traits. Lastly, both expression and genetic association showed that miR156i, miR156j, miR396a and miR6445b were involved in the formation of tension wood. This study shows that variants in miRNAs and target genes contribute to natural phenotypic variation and annotated roles and interactions of miRNAs and their target genes by genetic association analysis. PMID:27265357

  2. 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

  3. 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. PMID:26340850

  4. 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

  5. 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. PMID:25706044

  6. Computational strategies for understanding the nature of interaction in dioxin imprinted nanoporous trappers.

    PubMed

    Khan, Muntazir S; Pal, Sourav; Krupadam, Reddithota J

    2015-07-01

    A new computational model capable of understanding the nature of interactions in signature complexes formed between the template (2,3,7,8-tetrachlorodibenzo-p dioxin (TCDD)) and the functional monomers (methacrylic acid (MAA)) using density functional theory (DFT) has been designed. The polymer precursors were optimized for geometries in polymerization media, computing the interaction energies between template molecules and functional monomers of transient pre-polymerized complexes (PPC), and structural and vibrational properties reference to theoretical infrared spectra were computed using DFT of B3LYP/6 311+G(d,p) hybrid functional method. Atom in molecule theory was used to analyze the hydrogen-bonding characteristics of PPC of MAA-TCDD. Considering the theoretical titrations conducted in a virtual solvent box, it was found that the 1:4 molar ratio was required to form the most stable PPC in a given solvent system. The electron density plots indicate strong hydrogen bonding as shown by the 2pz dominant highest occupied molecular orbital (HOMO) character that could be the preferable sites of binding for target molecule, TCDD. Considering HOMO approach, the active adsorption sites in molecularly imprinted polymer was modeled to get insight on molecular recognition property for targeted molecule, TCDD. The proposed computational protocol is simple, accurate, and novel to design the polymer and is useful to predict the properties of polymer systems than the conventional theoretical analysis of template-monomer interactions. PMID:25703338

  7. In-Situ Investigation of Interactions between Magnesium Ion and Natural Organic Matter.

    PubMed

    Yan, Mingquan; Lu, Yujuan; Gao, Yuan; Benedetti, Marc F; Korshin, Gregory V

    2015-07-21

    Natural organic matter (NOM) generated in all niches of the environment constitutes a large fraction of the global pool of organic carbon while magnesium is one of the most abundant elements that has multiple roles in both biotic and abiotic processes. Although interactions between Mg(2+) and NOM have been recognized to affect many environmental processes, little is understood about relevant mechanisms and equilibria. This study addressed this deficiency and quantified Mg(2+)-NOM interactions using differential absorbance spectroscopy (DAS) in combination with the NICA-Donnan speciation model. DAS data were obtained for varying total Mg concentrations, pHs from 5.0 to 11.0 and ionic strengths from 0.001 to 0.3 mol L(-1). DAS results demonstrated the existence of strong interactions between magnesium and NOM at all examined conditions and demonstrated that the binding of Mg(2+) by NOM was accompanied by the replacement of protons in the protonation-active phenolic and carboxylic groups. The slope of the log-transformed absorbance spectra of NOM in the range of wavelength 350-400 nm was found to be indicative of the extent of Mg(2+)-NOM binding. The differential and absolute values of the spectral slopes were strongly correlated with the amount of NOM-bound Mg(2+) ions and with the concentrations of NOM-bound protons. PMID:26090773

  8. 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. PMID:25742369

  9. 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.

  10. The nature of the solar wind interaction with CO2/CO-dominated comets

    NASA Technical Reports Server (NTRS)

    Houpis, H. L. F.; Mendis, D. A.

    1981-01-01

    The nature of the interaction of the solar wind with the ionospheres (field-free ion cavities) of comets with CO or CO2 as their dominant volatile species is considered and compared with the solar wind interaction with H2O-diominated comets. Calculations of the heliocentric variation of scale lengths defined as the nuclear distance at which the mean free path for ion-neutral collisions becomes equal to the nuclear distance, and the ion and neutral stand-off distances are presented for different modes of energy addition, nuclear radii and ionization time scales. Results indicate that whereas little activity can be expected from H2O-dominated comets at distances beyond 3 AU, COand CO2-dominated comets can be expected to be quite prolific at such distances. In contrast to H2O-dominated comets characterized by weak shocks, CO/CO2-dominated comet solar wind interactions are found to produce strong bow shocks within a specific heliocentric distance for the isothermal case of a CO-dominated comet, and a weak shock outside of this distance. In the general case, two types of cometary ionosphere transitions are found: a transition from strong to weak bow shock and from a compressible (soft) to an incompressible (hard) ionosphere, and a transition from a soft to a hard ionosphere with the bow shock remaining weak at a heliocentric distance dependant on atmospheric optical depth, bolometric albedo, nuclear radius, latent heat of sublimation of nuclear material, ionization time scale and type of heat addition. It is pointed out that the behavior of Comet Humason can be explained by solar wind interactions with a CO- or CO2-dominated comet.

  11. 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. PMID:24836279

  12. 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. PMID:26771702

  13. 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…

  14. 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…

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

    PubMed

    Jacob, Claus

    2014-01-01

    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

  16. 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

  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. [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. PMID:27169225

  19. 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.

  20. On the performance of atomic natural orbital basis sets: A full configuration interaction study

    SciTech Connect

    Illas, F. Departament de Quimica Fisica, Grup de Quimica Quantica, Facultat de Quimica, Universitat de Barcelona, C Ricart, J.M. ); Rubio, J. ); Bagus, P.S. )

    1990-10-01

    The performance of atomic natural orbital (ANO) basis sets has been studied by comparing self-consistant field (SCF) and full configuration interaction (CI) results obtained for the first row atoms and hydrides. The ANO results have been compared with those obtained using a segmented basis set containing the same number of contracted basis functions. The total energies obtained with the ANO basis sets are always lower than the one obtained by using the segmented one. However, for the hydrides, differential electronic correlation energy obtained with the ANO basis set may be smaller than the one recovered with the segmented set. We relate this poorer differential correlation energy for the ANO basis set to the fact that only one contracted {ital d} function is used for the ANO and segmented basis sets.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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).

  6. Edges in agricultural landscapes: species interactions and movement of natural enemies.

    PubMed

    Macfadyen, Sarina; Muller, Warren

    2013-01-01

    Agricultural landscapes can be characterized as a mosaic of habitat patches interspersed with hostile matrix, or as a gradient of patches ranging from suitable to unsuitable for different species. Arthropods moving through these landscapes encounter a range of edges, with different permeability. Patches of native vegetation in these landscapes may support natural enemies of crop pests by providing alternate hosts for parasitic wasps and/or acting as a source for predatory insects. We test this by quantifying species interactions and measuring movement across different edge-types. A high diversity of parasitoid species used hosts in the native vegetation patches, however we recorded few instances of the same parasitoid species using hosts in both the native vegetation and the crop (canola). However, we did find overall greater densities of parasitoids moving from native vegetation into the crop. Of the parasitoid groups examined, parasitoids of aphids (Braconidae: Aphidiinae) frequently moved from native vegetation into canola. In contrast, parasitoids of caterpillars (Braconidae: Microgastrinae) moved commonly from cereal fields into canola. Late season samples showed both aphids and parasitoids moving frequently out of native vegetation, in contrast predators moved less commonly from native vegetation (across the whole season). The season-long net advantage or disadvantage of native vegetation for pest control services is therefore difficult to evaluate. It appears that the different edge-types alter movement patterns of natural enemies more so than herbivorous pest species, and this may impact pest control services. PMID:23555737

  7. Color and shape interactions in the recognition of natural scenes by human and monkey observers.

    PubMed

    Liebe, Stefanie; Fischer, Elvira; Logothetis, Nikos K; Rainer, Gregor

    2009-01-01

    Trichromatic color vision is a fundamental aspect of the visual system shared by humans and non-human primates. In human observers, color has been shown to facilitate object identification. However, little is known about the role that color plays in higher level vision of non-human primates. Here, we addressed this question and studied the interaction between luminance- and color-based structural information for the recognition of natural scenes. We present psychophysical data showing that both monkey and human observers equally profited from color when recognizing natural scenes, and they were equally impaired when scenes were manipulated using colored noise. This effect was most prominent for degraded image conditions. By using a specific procedure for stimulus degradation, we found that the improvement as well as the impairment in visual memory performance is due to contribution of image color independent of luminance-based object information. Our results demonstrate that humans as well as non-human primates exploit their sensory ability of color vision to achieve higher performance in visual recognition tasks especially when shape features are degraded. PMID:19757892

  8. Evaluating contributions of natural language parsers to protein–protein interaction extraction

    PubMed Central

    Miyao, Yusuke; Sagae, Kenji; Sætre, Rune; Matsuzaki, Takuya; Tsujii, Jun'ichi

    2009-01-01

    Motivation: While text mining technologies for biomedical research have gained popularity as a way to take advantage of the explosive growth of information in text form in biomedical papers, selecting appropriate natural language processing (NLP) tools is still difficult for researchers who are not familiar with recent advances in NLP. This article provides a comparative evaluation of several state-of-the-art natural language parsers, focusing on the task of extracting protein–protein interaction (PPI) from biomedical papers. We measure how each parser, and its output representation, contributes to accuracy improvement when the parser is used as a component in a PPI system. Results: All the parsers attained improvements in accuracy of PPI extraction. The levels of accuracy obtained with these different parsers vary slightly, while differences in parsing speed are larger. The best accuracy in this work was obtained when we combined Miyao and Tsujii's Enju parser and Charniak and Johnson's reranking parser, and the accuracy is better than the state-of-the-art results on the same data. Availability: The PPI extraction system used in this work (AkanePPI) is available online at http://www-tsujii.is.s.u-tokyo.ac.jp/-100downloads/downloads.cgi. The evaluated parsers are also available online from each developer's site. Contact: yusuke@is.s.u-tokyo.ac.jp PMID:19073593

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

    PubMed

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

    2014-07-01

    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. PMID:24664591

  10. 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.

  11. Dispersion interactions within the Piris natural orbital functional theory: the helium dimer.

    PubMed

    Piris, M; Lopez, X; Ugalde, J M

    2007-06-01

    The authors have investigated the description of the dispersion interaction within the Piris natural orbital functional (PNOF) theory. The PNOF arises from an explicit antisymmetric approach for the two-particle cumulant in terms of two symmetric matrices, Delta and Lambda. The functional forms of these matrices are obtained from the generalization of the two-particle system expressions, except for the off-diagonal elements of Delta. The mean value theorem and the partial sum rule obtained for the off-diagonal elements of Delta provide a prescription for deriving practical functionals. In particular, the previous employed approximation {Jpp/2} for the mean values {Jp*} affords several molecular properties but it is incapable to account for dispersion effects. In this work, the authors analyze a new approach for Jp* obtained by factorization of the matrix Delta within the bounds on its off-diagonal elements imposed by the positivity conditions of the two-particle reduced density matrix. Additional terms for the matrix elements of Lambda proportional to the square root of the holes are again introduced to describe properly the occupation numbers of the lowest occupied levels. The authors have found that the cross products between weakly occupied orbitals must be removed from the functional form of Lambda to obtain a correct long-range asymptotic behavior. The PNOF is used to predict the binding energy as well as the equilibrium distance of the helium dimer. The results are compared with the full configuration-interaction calculations and the corresponding experimental data. PMID:17567186

  12. Structural and Biochemical Characterization of the Interaction of Tubulin with Potent Natural Analogues of Podophyllotoxin.

    PubMed

    Antúnez-Mojica, Mayra; Rodríguez-Salarichs, Javier; Redondo-Horcajo, Mariano; León, Alejandra; Barasoain, Isabel; Canales, Ángeles; Cañada, F J; Jiménez-Barbero, Jesús; Alvarez, Laura; Díaz, J Fernando

    2016-08-26

    Four natural analogues of podophyllotoxin obtained from the Mexican medicinal plant Bursera fagaroides, namely, acetyl podophyllotoxin (2), 5'-desmethoxy-β-peltatin A methyl ether (3), 7',8'-dehydro acetyl podophyllotoxin (4), and burseranin (5), have been characterized, and their interactions with tubulin have been investigated. Cytotoxic activity measurements, followed by immunofluorescence microscopy and flow cytometry studies, demonstrated that these compounds disrupt microtubule networks in cells and cause cell cycle arrest in the G2/M phase in the A549 cell line. A tubulin binding assay showed that compounds 1-4 were potent assembly inhibitors, displaying binding to the colchicine site with Kb values ranging from 11.75 to 185.0 × 10(5) M(-1). In contrast, burseranin (5) was not able to inhibit tubulin assembly. From the structural perspective, the ligand-binding epitopes of compounds 1-3 have been mapped using STD-NMR, showing that B and E rings are the major points for interaction with the protein. The obtained results indicate that the inhibition of tubulin assembly of this family of compounds is more effective when there are at least two methoxyl groups at the E ring, along with a trans configuration of the lactone ring in the aryltetralin lignan core. PMID:27518758

  13. 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.

  14. Selective toxin-lipid membrane interactions of natural, haemolytic Scyphozoan toxins analyzed by surface plasmon resonance.

    PubMed

    Helmholz, Heike

    2010-10-01

    A comparison of the molecular interaction of natural Scyphozoan lysins with their bioactivity in a haemolytic assay was performed by establishing an efficient, automatable and reproducible procedure for the measurement of protein-membrane interactions. The toxin-membrane interactions were analyzed utilising a chip-based technology with immobilized liposomes as artificial cell membranes. The technique was established with streptolysin O as a cholesterol-selective model toxin and its cholesterol-selectivity has been proven. The haemolytic potency of protein fractions derived from the venom of the jellyfish Aurelia aurita and Cyanea capillata was tested and EC50 values of 35.3mug/mL and 43.1mug/mL against sheep and 13.5mug/mL and 8.8mug/mL against rabbit erythrocytes were measured. Cell membrane binding as a first step in the haemolytic process was analyzed using the Biacore((R)) technology. Major cell membrane lipids (cholesterol, sphingomyelin and phosphatidylcholine) were immobilized as pure liposomes and in binary mixtures. A preference for cholesterol and sphingomyelin of both jellyfish species was demonstrated. The specificity of the method was proven with a non-haemolytic A. aurita protein fraction that did not express a lipid binding. Additionally, an inactivated C. capillata lysine with negligible haemolytic activity showed a remaining but reduced adsorption onto lipid layers. The binding level of the lytic venom fraction of these dominant boreal jellyfish species increased as a function of protein concentration. The binding strength was expressed in RU50 values ranging from 12.4mug/mL to 35.4mug/mL, which were in the same order of magnitude as the EC50 values in the haemolytic assay. PMID:20599534

  15. 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

  16. 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

  17. 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. PMID:10842787

  18. 5G: rethink mobile communications for 2020.

    PubMed

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

    2016-03-01

    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. PMID:26809577

  19. Assessment of the nature interactions of β-amyloid protein by a nanoprobe method.

    PubMed

    Caballero, Leonardo; Mena, Juan; Morales-Alvarez, Aurora; Kogan, Marcelo J; Melo, Francisco

    2015-01-01

    We present a method based on atomic force microscopy (AFM) to assess the work of adhesion between the interfaces of gold AFM tips functionalized with three peptides derived from β-sheet breaker LPFFD [CLPFFD-NH2 (i0) and their isomers CDLPFF-NH2 (i1) and CLPDFF-NH2 (i2)], and the beta-amyloid protein (Aβ1-42). β-Amyloid protein was deposited onto a highly oriented graphite (HOPG) surface as protofibrils and fibrils. The presence of the residues Leu (L), Phe (F), and Phe (F), which are also present in the native sequence, confirm that the peptides are able to bind to the aggregates of Aβ1-42 fibrils and protofibrils. Force of adhesion data were directly obtained from the maximum force on retraction, and the work of adhesion was calculated from the Jhonson-Kendall-Roberts model (JKR-Model). Both the polar and dispersive contributions to the surface energy of the peptides i0, i1, and i2, as well as Aβ1-42 fibrils and protofibrils, were determined by means of measuring the contact angle and using the two-fluid method. The macroscopic energies of the functionalized gold surfaces do not differ significantly between isomers, which confirms the similar nature of the peptides i0, i1, and i2 but suggests that the macroscopic measurements are not able to distinguish specific sequences. The nanoprobe reveals a typical adhesion work value associated with the interaction of protofibrils with i0 and i2; this value is three times higher than that of i1. The difference is attributed to the hydrophobic nature of protofibrils, the predominant exposition of hydrophobic residues of the peptides i0 and i2, with respect to i1, and the degree of functionalization. i0 and i2 presented a slight adhesion with Aβ fibrils, which is associated with the exposed hydrophilic groups of these fibrils (onto HOPG) compared to the protofibrils. However, i1 showed interaction with both Aβ fibrils and protofibrils. For this, we propose an explanation based on the fact that the peptide i1 locates

  20. 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

  1. Schooling for Happiness: Rethinking the Aims of Education

    ERIC Educational Resources Information Center

    Cavanagh, Tom

    2008-01-01

    The release of "The New Zealand Curriculum" causes us to rethink the aims of education. Dr Cavanagh offers an alternative set of aims to the vision outlined in the Ministry of Education document, which is based, at least in part, on socialisation into the corporate industrial world. Dr Cavanagh's position is focused on putting relationships at the…

  2. 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.…

  3. 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…

  4. 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: Inviting Students' Lives into…

  5. 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…

  6. 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…

  7. Rethinking Themes for Teaching the Era of the Cold War.

    ERIC Educational Resources Information Center

    Rosenberg, Norman L.; Rosenberg, Emily S.

    1994-01-01

    Maintains that the "tried and true" strategies for teaching about the early Cold War years highlight the U.S. response to Soviet expansionism. Identifies four other focus themes: (1) debates over mass culture and youth culture; (2) gender and sexuality; (3) the civil rights era; and (4) rethinking the cold war itself. (CFR)

  8. Rethinking "At-Risk" in Drama Education: Beyond Prescribed Roles

    ERIC Educational Resources Information Center

    Conrad, Diane

    2005-01-01

    Concern over students deemed "at-risk" constructs youth as deficient and deviant without considering the experiences of youth themselves. My interest in "at-risk" grows out of my previous work with youth, in various drama education contexts and the fact that youth have told me they found the label offensive. My research re-thinks "at-risk" to…

  9. 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…

  10. Comment on "Schooling for Happiness: Rethinking the Aims of Education"

    ERIC Educational Resources Information Center

    Glynn, Ted

    2008-01-01

    This commentary presents the author's response to an article published in the last version of "Kairaranga" entitled "Schooling for Happiness: Rethinking the aims of education," written by Dr. Tom Cavanagh. He found it refreshing to read Cavanagh's article that focuses educators' energies onto re-visiting the wider socio-cultural goals of…

  11. 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,…

  12. When Learning Counts: Rethinking Licenses for School Leaders

    ERIC Educational Resources Information Center

    Adams, Jacob E., Jr.; Copland, Michael A.

    2005-01-01

    This report asks two fundamental questions: do the licenses that states require of school principals encompass the knowledge and skills those principals need to promote student learning? If not, what kind of policy framework would help decision makers, educators, and others rethink principal licenses and the school leadership they support? To find…

  13. Extending, Broadening and Rethinking Existing Research on Transfer of Training

    ERIC Educational Resources Information Center

    Volet, Simone

    2013-01-01

    The aim of this Special Issue was to generate a new integrated agenda for research on transfer of training. It brought together scholars from diverse perspectives and invited them to strive toward synergy. This article examines how this collection of articles, as well as other bodies of literature, can help extend, broaden and rethink current…

  14. Rethinking the morality of animal research.

    PubMed

    Tannenbaum, J; Rowan, A N

    1985-10-01

    A review is provided of major ethical positions concerning the moral status of animals and the use of animals in research. These positions are characterized as ethical skepticism and relativism, absolute dominionism, anthropocentric consequentialism, reverence for life, utilitarianism, and abolitionism. The authors contend that any acceptable ethical discussion of the use of research animals must take into account suffering and well-being, pleasure, thought and reason, purposiveness, and self awareness. Other issues to be addressed are the nature of different animals and the principle of social interaction with humans. Justifications for animal research may be based on claims of benefits to humans, benefits to other animals, or the value of research to science and knowledge. PMID:3905706

  15. Experimental Determination of the Electrostatic Nature of Carbonyl Hydrogen-Bonding Interactions Using IR-NMR Correlations.

    PubMed

    Kashid, Somnath M; Bagchi, Sayan

    2014-09-18

    Hydrogen-bonding plays a fundamental role in the structure, function, and dynamics of various chemical and biological systems. Understanding the physical nature of interactions and the role of electrostatics in hydrogen-bonding has been the focus of several theoretical and computational research. We present an experimental approach involving IR-(13)C NMR correlations to determine the electrostatic nature of carbonyl hydrogen-bonding interactions. This report provides a direct experimental evidence of the classical nature of hydrogen-bonding interaction in carbonyls, independent of any theoretical approximation. These results have important implications in chemistry and biology and can be applied to probe the reaction mechanisms involving carbonyl activation/stabilization by hydrogen bonds using spectroscopic techniques. PMID:26276334

  16. 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.

  17. 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.

  18. Nature of protein-CO2 interactions as elucidated via molecular dynamics.

    PubMed

    Drummond, Michael L; Wilson, Angela K; Cundari, Thomas R

    2012-09-27

    Rising global temperatures require innovative measures to reduce atmospheric concentrations of CO(2). The most successful carbon capture technology on Earth is the enzymatic capture of CO(2) and its sequestration in the form of glucose. Efforts to improve upon or mimic this naturally occurring process will require a rich understanding of protein-CO(2) interactions. Toward that end, extensive all-atom molecular dynamics (MD) simulations were performed on the CO(2)-utilizing enzyme phosphoenolpyruvate carboxykinase (PEPCK). Preliminary simulations were performed using implicit and explicit solvent models, which yielded similar results: arginine, lysine, tyrosine, and asparagine enhance the ability of a protein to bind carbon dioxide. Extensive explicit solvent simulations were performed for both wild-type PEPCK and five single-point PEPCK mutants, revealing three prevalent channels by which CO(2) enters (or exits) the active site cleft, as well as a fourth channel (observed only once), the existence of which can be rationalized in terms of the position of a key Arg residue. The strongest CO(2) binding sites in these simulations consist of appropriately positioned hydrogen bond donors and acceptors. Interactions between CO(2) and both Mn(2+) and Mg(2+) present in PEPCK are minimal due to the stable protein- and solvent-based coordination environments of these cations. His 232, suggested by X-ray crystallography as being a potential important CO(2) binding site, is indeed found to be particularly "CO(2)-philic" in these simulations. Finally, a recent mechanism, proposed on the basis of X-ray crystallography, for PEPCK active site lid closure is discussed in light of the MD trajectories. Overall, the results of this work will prove useful not only to scientists investigating PEPCK, but also to groups seeking to develop an environmentally benign, protein-based carbon capture, sequestration, and utilization system. PMID:22882078

  19. 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.

  20. 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.

  1. Glutathione transferase from Plasmodium falciparum--interaction with malagashanine and selected plant natural products.

    PubMed

    Mangoyi, Rumbidzai; Hayeshi, Rose; Ngadjui, Bonventure; Ngandeu, Francois; Bezabih, Merhatibebe; Abegaz, Berhanu; Razafimahefa, Solofoniaina; Rasoanaivo, Philippe; Mukanganyama, Stanley

    2010-12-01

    A glutathione transferase (PfGST) isolated from Plasmodium falciparum has been associated with chloroquine resistance. A range of natural products including malagashanine (MG) were screened for inhibition of PfGST by a GST assay with 1-chloro-2,4-dinitrobenzene as a substrate. Only the sesquiterpene (JBC 42C), the bicoumarin (Tral-1), ellagic acid and curcumin, were shown to be potent inhibitors of PfGST with IC(50) values of 8.5, 12, 50 and 69 μM, respectively. Kinetic studies were performed on PfGST using ellagic acid as an inhibitor. Uncompetitive and mixed types of inhibition were obtained for glutathione (GSH) and 1-chloro-2, 4-dinitrobenzene (CDNB). The K(i) for GSH and CDNB were -0.015 μM and 0.011 μM, respectively. Malagashanine (100 µM) only reduced the activity of PfGST to 80% but showed a time-dependent inactivation of PfGST with a t(1/2) of 34 minutes compared to >120 minutes in the absence of MG or in the presence of 5 mM GSH. This work facilitates the understanding of the interaction of PfGST with some plant derived compounds. PMID:20521884

  2. 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. PMID:24036528

  3. 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. PMID:20194743

  4. 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. PMID:23106703

  5. 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.

  6. Natural Variation for Carbohydrate Content in Arabidopsis. Interaction with Complex Traits Dissected by Quantitative Genetics1

    PubMed Central

    Calenge, Fanny; Saliba-Colombani, Véra; Mahieu, Stéphanie; Loudet, Olivier; Daniel-Vedele, Françoise; Krapp, Anne

    2006-01-01

    Besides being a metabolic fuel, carbohydrates play important roles in plant growth and development, in stress responses, and as signal molecules. We exploited natural variation in Arabidopsis (Arabidopsis thaliana) to decipher the genetic architecture determining carbohydrate content. A quantitative trait locus (QTL) approach in the Bay-0 × Shahdara progeny grown in two contrasting nitrogen environments led to the identification of 39 QTLs for starch, glucose, fructose, and sucrose contents representing at least 14 distinct polymorphic loci. A major QTL for fructose content (FR3.4) and a QTL for starch content (ST3.4) were confirmed in heterogeneous inbred families. Several genes associated with carbon (C) metabolism colocalize with the identified QTL. QTLs for senescence-related traits, and for flowering time, water status, and nitrogen-related traits, previously detected with the same genetic material, colocalize with C-related QTLs. These colocalizations reflect the complex interactions of C metabolism with other physiological processes. QTL fine-mapping and cloning could thus lead soon to the identification of genes potentially involved in the control of different connected physiological processes. PMID:16798941

  7. How do natural, uncultivated microbes interact with organic matter? Insights from single cell genomics and metagenomics

    NASA Astrophysics Data System (ADS)

    Lloyd, K. G.; Bird, J.; Schreiber, L.; Petersen, D.; Kjeldsen, K.; Schramm, A.; Stepanauskas, R.; Jørgensen, B. B.

    2013-12-01

    Since most of the microbes in marine sediments remain uncultured, little is known about the mechanisms by which these natural communities degrade organic matter (OM). Likewise, little is known about the make-up of labile OM in marine sediments beyond general functional classes such as proteins, carbohydrates, and lipids, measured as monomers. However, microbes have complex interactions with specific polymers within these functional classes, which can be indicated by a microbe's enzymatic toolkit. We found that four single cell genomes of archaea have very different peptidase compositions than four single cells of bacteria, suggesting that archaea and bacteria may play different roles in OM degradation. We also found that predicted extracellular cysteine peptidases, which require chemically reducing conditions, were common in IMG database metagenomes from marine sediments, and absent in those from seawater. This suggests that the pathways, and not just the rates, of OM degradation may differ between seawater and sediments. By comparing enzyme classes in different organisms, or in different types of marine environments, we present an emerging view of the microbial potential for specific carbon remineralization pathways in marine sediments. In addition, the methods we present hold promise for characterizing OM degradation in any environment where genomic information is available.

  8. 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. PMID:27332782

  9. Hydrogeophysical Characterizations of Streambed Sedimentology and Stream-Groundwater Interactions in a Natural Stream

    NASA Astrophysics Data System (ADS)

    Hyun, Y.; Lee, S.; Kim, H.; Lee, K.

    2011-12-01

    than values at 10 cm depth due to, getting to deep, existence of low permeable sediments like loamy sand and silt loam. Depositional features of streambed in a natural stream are predicted to affect both vertical water flux and pattern on surface water-groundwater interaction. This subject is supported by Brain Korea 21 and Korea Ministry of Environment as 'The GAIA Project (173-092-009)'

  10. 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. PMID:24326533

  11. 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.…

  12. 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.

  13. Effects of Naturally Occuring Arginine 14 Deletion on Phospholamban Conformational Dynamics and Membrane Interactions

    PubMed Central

    Vostrikov, Vitaly V.; Soller, Kailey J.; Ha, Kim N.; Gopinath, T.; Veglia, Gianluigi

    2014-01-01

    Phospholamban (PLN) is a single-pass membrane protein that regulates the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA). Phosphorylation of PLN at Ser16 reverses its inhibitory function under β-adrenergic stimulation, augmenting Ca2+ uptake in the sarcoplasmic reticulum and muscle contractility. PLN exists in two conformations; a T state, where the cytoplasmic domain is helical and absorbed on the membrane surface, and an R state, where the cytoplasmic domain is unfolded and membrane detached. Previous studies from our group have shown that the PLN conformational equilibrium is crucial to SERCA regulation. Here, we used a combination of solution and solid-state NMR techniques to compare the structural topology and conformational dynamics of monomeric PLN (PLNAFA) with that of the PLNR14del, a naturally occurring deletion mutant that is linked to the progression of dilated cardiomyopathy. We found that the behavior of the inhibitory transmembrane domain of PLNR14del is similar to that of the native sequence. In contrast, the conformational dynamics of R14del both in micelles and lipid membranes are enhanced. We conclude that the deletion of Arg14 in the cytoplasmic region weakens the interactions with the membrane and shifts the conformational equilibrium of PLN toward the disordered R state. This conformational transition is correlated with the loss-of-function character of this mutant and is corroborated by SERCA’s activity assays. These findings further support our hypothesis that SERCA function is fine-tuned by PLN conformational dynamics and begin to explain the aberrant regulation of SERCA by the R14del mutant. PMID:25251363

  14. 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

  15. Oxygen Modulates Human Decidual Natural Killer Cell Surface Receptor Expression and Interactions with Trophoblasts1

    PubMed Central

    Wallace, Alison E.; Goulwara, Sonu S.; Whitley, Guy S.; Cartwright, Judith E.

    2014-01-01

    Decidual natural killer (dNK) cells have been shown to both promote and inhibit trophoblast behavior important for decidual remodeling in pregnancy and have a distinct phenotype compared to peripheral blood NK cells. We investigated whether different levels of oxygen tension, mimicking the physiological conditions of the decidua in early pregnancy, altered cell surface receptor expression and activity of dNK cells and their interactions with trophoblast. dNK cells were isolated from terminated first-trimester pregnancies and cultured in oxygen tensions of 3%, 10%, and 21% for 24 h. Cell surface receptor expression was examined by flow cytometry, and the effects of secreted factors in conditioned medium (CM) on the trophoblast cell line SGHPL-4 were assessed in vitro. SGHPL-4 cells treated with dNK cell CM incubated in oxygen tensions of 10% were significantly more invasive (P < 0.05) and formed endothelial-like networks to a greater extent (P < 0.05) than SGHPL-4 cells treated with dNK cell CM incubated in oxygen tensions of 3% or 21%. After 24 h, a lower percentage of dNK cells expressed CD56 at 21% oxygen (P < 0.05), and an increased percentage of dNK cells expressed NKG2D at 10% oxygen (P < 0.05) compared to other oxygen tensions, with large patient variation. This study demonstrates dNK cell phenotype and secreted factors are modulated by oxygen tension, which induces changes in trophoblast invasion and endovascular-like differentiation. Alterations in dNK cell surface receptor expression and secreted factors at different oxygen tensions may represent regulation of function within the decidua during the first trimester of pregnancy. PMID:25232021

  16. 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.…

  17. 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

  18. 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"…

  19. 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.

  20. 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'.

  1. 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

  2. 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

  3. Interactions between radioactively labeled colloids and natural particles: Evidence for colloidal pumping

    NASA Astrophysics Data System (ADS)

    Wen, Liang-Saw; Santschi, Peter H.; Tang, Degui

    1997-07-01

    It has been hypothesized that colloidal forms of trace metals can be reactive intermediaries in the scavenging processes leading to the removal of their particulate forms. A series of radiotracer experiments using natural colloidal organic matter from Galveston Bay, USA were carried out in order to test this hypothesis. Suspended particle uptake of originally colloidally bound trace metals occurred in a matter of hours to days in estuarine waters. After ten days, the majority (>50%) of the colloidal trace metals had been transferred into the particulate phase (≥0.45 μm), except for 65Zn. Two distinctively different temporal regions of removal of colloidal trace metals were identified: a faster reaction during the first four hours, followed by a slower reaction after approximately one day. In a separate river water-seawater mixing experiment, the solid/solution partitioning of the radiotracers was investigated in the absence of suspended matter. About 30% of most of the elements, except Ag and Fe (˜60%), were associated with a newly formed particulate phase after eight days. There were two major trends: (1) the particulate fraction of 59Fe and 110Ag increased while the colloidal fraction decreased, suggesting a colloidal pumping mechanism. (2) The particulate fraction of 54Mn, 133Ba, 65Zn, 109Cd, 113Sn, and 60CO increased while the LMW (≤ 1 kDa) fraction decreased, suggesting a direct uptake into the particulate fraction with less involvement of a transitory colloidal phase. The values of the particle-water ( Kd) and colloid-water partitioning ( Kc) coefficients for most trace metals were similar to those observed in Galveston Bay waters, suggesting complementary results to field studies. The results from these experiments suggested two different pathways for colloidal tracer uptake by particles: (1) colloidal pumping of a major component (e.g., biopolymer) of the colloidal pool and (2) coagulation of trace components (e.g., phytochelatins) with varying

  4. 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

  5. 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.

  6. Modulation of natural killer cell functions by interactions between 2B4 and CD48 in cis and in trans

    PubMed Central

    Claus, Maren; Wingert, Sabine

    2016-01-01

    SLAM-related receptors (SRRs) are important modulators of immune cell function. While most SRRs are homophilic, 2B4 (CD244) interacts with CD48, a GPI-anchored protein expressed on many haematopoietic cells. Here we show that natural killer (NK) cell-expressed 2B4 not only binds in trans to CD48 on neighbouring cells but also interacts in cis with CD48 on the same cell. 2B4 uses the same binding site to interact with CD48 in cis and in trans and structural flexibility of 2B4 is necessary for the cis interaction. Furthermore, the cis interaction is sufficient to induce basal phosphorylation of 2B4. However, cis interaction reduces the ability of 2B4 to bind CD48 in trans. As a consequence, stimulation-dependent phosphorylation of 2B4 upon binding to CD48 positive target cells is reduced. Interfering with the cis interaction therefore enhanced the lysis of CD48-expressing tumour cells. These data show that the density of 2B4 and CD48 on both the NK cell and the potential target cell modulates NK cell activity. PMID:27249817

  7. Interactive Perceptual Psychology: The Human Psychology That Mirrors the Naturalness of Human Behavior.

    ERIC Educational Resources Information Center

    Russell, Gary F.; Shoare, Linda

    This study presents results of research on the impact of Interactive Perceptual Psychology (IPP) on teachers. IPP is the psychology showing human behavior as the sum of internal energy derived from thinking, feeling, and acting. This energy comes from the interaction among 10 receptors found within each human being: (1) "man's" will; (2) internal…

  8. Utilization of mutants to analyze the interaction between Arabidopsis thaliana and its naturally root-associated Pseudomonas.

    PubMed

    Persello-Cartieaux, F; David, P; Sarrobert, C; Thibaud, M C; Achouak, W; Robaglia, C; Nussaume, L

    2001-01-01

    A model system based on the Arabidopsis thaliana (L.) Heynh. Ws ecotype and its naturally colonizing Pseudomonas thivervalensis rhizobacteria was defined. Pseudomonas strains colonizing A. thaliana were found to modify the root architecture either in vivo or in vitro. A gnotobiotic system using bacteria labelled with green fluorescent protein revealed that P. thivervalensis exhibited a colonization profile similar to that of other rhizobacterial species. Mutants of A. thaliana affected in root hair development and possible hormone perception were used to analyze the plant genetic determinants of bacterial colonization. A screen for mutants insensitive to P. thivervalensis colonization yielded two mutants found to be auxin resistant. This further supports a proposed role for bacterial auxin in inducing morphological modifications of roots. This work paves the way for studying the interaction between plants and non-pathogenic rhizobacteria in a gnotobiotic system, derived from a natural association, where interactions between both partners can be genetically dissected. PMID:11216839

  9. 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. PMID:23045887

  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. Humic acids: Characterization and interactions in natural and wastewater systems. (Latest citations from Pollution Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-09-01

    The bibliography contains citations concerning the absorptive and complexation properties of humic and fulvic acids. Characterization and the occurrence of these acids in wastewater systems and natural systems are studied. The interaction of humic substances with metallic pollutants and chlorinated hydrocarbons, and removal of humic acids by precipitation are among the topics discussed. Wastewater treatment processes are discussed in separate bibliographies. (Contains 250 citations and includes a subject term index and title list.)

  12. Humic acids: Characterization and interactions in natural and wastewater systems. (Latest citations from Pollution abstracts). Published Search

    SciTech Connect

    1995-11-01

    The bibliography contains citations concerning the absorptive and complexation properties of humic and fulvic acids. Characterization and the occurrence of these acids in wastewater systems and natural systems are studied. The interaction of humic substances with metallic pollutants and chlorinated hydrocarbons, and removal of humic acids by precipitation are among the topics discussed. Wastewater treatment processes are discussed in separate bibliographies. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  13. Humic acids: Characterization and interactions in natural and wastewater systems. (Latest citations from Pollution abstracts). Published Search

    SciTech Connect

    Not Available

    1993-11-01

    The bibliography contains citations concerning the absorptive and complexation properties of humic and fulvic acids. Characterization and the occurrence of these acids in wastewater systems and natural systems are studied. The interaction of humic substances with metallic pollutants and chlorinated hydrocarbons, and removal of humic acids by precipitation are among the topics discussed. Wastewater treatment processes are discussed in separate bibliographies. (Contains 250 citations and includes a subject term index and title list.)

  14. 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...

  15. The Nature of Staff - Family Interactions in Nursing Homes: Staff Perceptions

    PubMed Central

    Colón-Emeric, Cathleen S.; Lekan-Rutledge, Deborah; Ammarell, Natalie; Bailey, Donald; Corazzini, Kirsten; Piven, Mary L.; Anderson, Ruth A.

    2008-01-01

    Each year thousands of older adults are admitted to nursing homes. Following admission, nursing home staff and family members must interact and communicate with each other. This study examined relationship and communication patterns between nursing home staff members and family members of nursing home residents, as part of a larger multi-method comparative case study. Here, we report on 6- month case studies of two nursing homes where in-depth interviews, shadowing experiences, and direct observations were completed. Staff members from both nursing homes described staff-family interactions as difficult, problematic and time consuming, yet identified strategies that when implemented consistently, influenced the staff-family interaction positively. Findings suggest explanatory processes in staff-family interactions, while pointing toward promising interventions. PMID:19649311

  16. 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

  17. 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. PMID:19068053

  18. Minor Allele Frequency Changes the Nature of Genotype by Environment Interactions.

    PubMed

    Verhulst, Brad; Neale, Michael C

    2016-09-01

    In the classical twin study, phenotypic variation is often partitioned into additive genetic (A), common (C) and specific environment (E) components. From genetical theory, the outcome of genotype by environment interaction is expected to inflate A when the interacting factor is shared (i.e., C) between the members of a twin pair. We show that estimates of both A and C can be inflated. When the shared interacting factor changes the size of the difference between homozygotes' means, the expected sibling or DZ twin correlation is .5 if and only if the minor allele frequency (MAF) is .5; otherwise the expected DZ correlation is greater than this value, consistent (and confounded) with some additional effect of C. This result is considered in the light of the distribution of minor allele frequencies for polygenic traits. Also discussed is whether such interactions take place at the locus level or affect an aggregated biological structure or system. Interactions with structures or endophenotypes that result from the aggregated effects of many loci will generally emerge as part of the A estimate. PMID:27105628

  19. On the nature of the interaction between structures and actuators in vibration suppression

    NASA Technical Reports Server (NTRS)

    Inman, Daniel J.; Garcia, Ephrahim; Umland, Jeff

    1990-01-01

    This lecture presents a summary of work on the analysis of the interaction between a structure, an actuator used to suppress the vibration of the structure, and the control law implemented by the actuator. Two control applications are considered. First, a proof-mass actuator with experimentally verified dynamics, capable of being used in a space structure configuration is examined. This is connected to a cantilevered beam modeled as a single degree of freedom system. Secondly, an electric motor, again with experimentally verified dynamics, is used to slew a beam modeled by a partial differential equation. Both the experimental and numerical configuration predict the presence of potential instabilities in system performance if proper consideration is not given to interactions between the control law, the structure and the actuator. In addition, an understanding of the interaction is shown to greatly effect performance. In particular it is shown that judicious choice of actuator parameters greatly improves closed loop performance.

  20. Rethinking Strategy and Strategic Leadership in Schools.

    ERIC Educational Resources Information Center

    Davies, Brent

    2003-01-01

    Reviews nature of strategy and strategic leadership in schools. Considers how leaders can map and reconceptualize the nature of strategy and develop strategic capabilities for longer-term sustainability. Questions hierarchical models of leadership. Highlights three characteristics of strategically oriented schools; suggests ways to improve art of…

  1. 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.

  2. Nature of the Surface and Its Effect on Solid-state Interactions

    NASA Technical Reports Server (NTRS)

    Georges, J. M.

    1984-01-01

    An important aspect of the friction and wear of solids is the nature and the mechanical behavior of the surface films. A description of the mechanical, physical, and chemical behavior of surface films is achieved by an investigation of boundary lubrication. Two major points are demonstrated. First, the sliding of two solid surfaces under boundary lubricating conditions creates third bodies in the interface. Second, the nature and the evolution of the interface are dictated by the colloidal behavior of the products generated. To illustrate these two propositions, some recent work is presented.

  3. Depth Camera-Based 3D Hand Gesture Controls with Immersive Tactile Feedback for Natural Mid-Air Gesture Interactions

    PubMed Central

    Kim, Kwangtaek; Kim, Joongrock; Choi, Jaesung; Kim, Junghyun; Lee, Sangyoun

    2015-01-01

    Vision-based hand gesture interactions are natural and intuitive when interacting with computers, since we naturally exploit gestures to communicate with other people. However, it is agreed that users suffer from discomfort and fatigue when using gesture-controlled interfaces, due to the lack of physical feedback. To solve the problem, we propose a novel complete solution of a hand gesture control system employing immersive tactile feedback to the user's hand. For this goal, we first developed a fast and accurate hand-tracking algorithm with a Kinect sensor using the proposed MLBP (modified local binary pattern) that can efficiently analyze 3D shapes in depth images. The superiority of our tracking method was verified in terms of tracking accuracy and speed by comparing with existing methods, Natural Interaction Technology for End-user (NITE), 3D Hand Tracker and CamShift. As the second step, a new tactile feedback technology with a piezoelectric actuator has been developed and integrated into the developed hand tracking algorithm, including the DTW (dynamic time warping) gesture recognition algorithm for a complete solution of an immersive gesture control system. The quantitative and qualitative evaluations of the integrated system were conducted with human subjects, and the results demonstrate that our gesture control with tactile feedback is a promising technology compared to a vision-based gesture control system that has typically no feedback for the user's gesture inputs. Our study provides researchers and designers with informative guidelines to develop more natural gesture control systems or immersive user interfaces with haptic feedback. PMID:25580901

  4. Depth camera-based 3D hand gesture controls with immersive tactile feedback for natural mid-air gesture interactions.

    PubMed

    Kim, Kwangtaek; Kim, Joongrock; Choi, Jaesung; Kim, Junghyun; Lee, Sangyoun

    2015-01-01

    Vision-based hand gesture interactions are natural and intuitive when interacting with computers, since we naturally exploit gestures to communicate with other people. However, it is agreed that users suffer from discomfort and fatigue when using gesture-controlled interfaces, due to the lack of physical feedback. To solve the problem, we propose a novel complete solution of a hand gesture control system employing immersive tactile feedback to the user's hand. For this goal, we first developed a fast and accurate hand-tracking algorithm with a Kinect sensor using the proposed MLBP (modified local binary pattern) that can efficiently analyze 3D shapes in depth images. The superiority of our tracking method was verified in terms of tracking accuracy and speed by comparing with existing methods, Natural Interaction Technology for End-user (NITE), 3D Hand Tracker and CamShift. As the second step, a new tactile feedback technology with a piezoelectric actuator has been developed and integrated into the developed hand tracking algorithm, including the DTW (dynamic time warping) gesture recognition algorithm for a complete solution of an immersive gesture control system. The quantitative and qualitative evaluations of the integrated system were conducted with human subjects, and the results demonstrate that our gesture control with tactile feedback is a promising technology compared to a vision-based gesture control system that has typically no feedback for the user's gesture inputs. Our study provides researchers and designers with informative guidelines to develop more natural gesture control systems or immersive user interfaces with haptic feedback. PMID:25580901

  5. 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…

  6. 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…

  7. [Natural toxins in inter- and intraspecies interaction of human being (elements of ethnotoxinology)].

    PubMed

    Gelashvili, D B

    2002-01-01

    The author considers the application of natural toxins as arrow poison by Homo sapiens from ancient time till today for hunting and ethnic wars on the example of natives of Asia, Africa, South America and Oceania. Geographic isolation was important determining the spectrum of natural toxin sources and the methods of their application. Cellular and molecular mechanisms of arrow poisons effects are considered in biogeographical context: aconitin and strychnin in Asia, diamphotoxin in Africa, indole alcaloids of plants and steroid alcaloids of amphibian in Central and South America, palytoxin in Oceania islands. High efficiency and selective effect of natural toxins allow to use them as molecular markers in current studies of functional membrane architecture and cellular structures. Great differences in pace of civilization development leads to the co-existence at the beginning of the XXI century ethnic groups that use natural toxins as arrow poison and human beings that use the same toxins in fundamental and applied investigations within international scientific society. PMID:12070945

  8. Self-Regulated Learning in Learning Environments with Pedagogical Agents that Interact in Natural Language

    ERIC Educational Resources Information Center

    Graesser, Arthur; McNamara, Danielle

    2010-01-01

    This article discusses the occurrence and measurement of self-regulated learning (SRL) both in human tutoring and in computer tutors with agents that hold conversations with students in natural language and help them learn at deeper levels. One challenge in building these computer tutors is to accommodate, encourage, and scaffold SRL because these…

  9. 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,…

  10. 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...

  11. 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...

  12. Enzyme-clay interactions and their impact on transformations of natural and anthropogenic organic compounds in soil

    SciTech Connect

    Naidja, A.; Huang, P.M.; Bollag, J.M.

    2000-06-01

    Soil is a living system in which enzymes are present either free in solution or bound to clay and clay-humus complexes. Enzyme-clay interactions play a key role in transforming organic compounds in soil environments where the decomposition and synthetic processes are largely catalyzed by enzymes. Scientific evidence indicates that mineral colloids take part in the catalysis of degradative and synthetic reactions of organic compounds. Such information is essential to understanding the role of mineral colloids, the hidden half of the enzyme-mineral colloid complexes, in catalytic reactions. Despite the abundant literature on the enzyme interactions with pure crystalline aluminosilicates, the nature of enzyme association with soil constituents, including both clean and coated clay minerals and other mineral colloids, and the effect on soil processes still remain unclear. This study integrates the existing information, including recent findings on enzyme-mineral colloid interactions and their effect on natural and anthropogenic organic compound transformation in soil. Further, the study focuses on the catalytic role of enzyme-clay complex surfaces in toxic industrial and agricultural compound bioremediation in soil and water environments.

  13. 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.

  14. Cytoplasmic genetic variation and extensive cytonuclear interactions influence natural variation in the metabolome

    PubMed Central

    Joseph, Bindu; Corwin, Jason A; Li, Baohua; Atwell, Suzi; Kliebenstein, Daniel J

    2013-01-01

    Understanding genome to phenotype linkages has been greatly enabled by genomic sequencing. However, most genome analysis is typically confined to the nuclear genome. We conducted a metabolomic QTL analysis on a reciprocal RIL population structured to examine how variation in the organelle genomes affects phenotypic variation. This showed that the cytoplasmic variation had effects similar to, if not larger than, the largest individual nuclear locus. Inclusion of cytoplasmic variation into the genetic model greatly increased the explained phenotypic variation. Cytoplasmic genetic variation was a central hub in the epistatic network controlling the plant metabolome. This epistatic influence manifested such that the cytoplasmic background could alter or hide pairwise epistasis between nuclear loci. Thus, cytoplasmic genetic variation plays a central role in controlling natural variation in metabolomic networks. This suggests that cytoplasmic genomes must be included in any future analysis of natural variation. DOI: http://dx.doi.org/10.7554/eLife.00776.001 PMID:24150750

  15. 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.

  16. 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. PMID:26454181

  17. 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

  18. Allosteric interactions and the modular nature of the voltage- and Ca2+-activated (BK) channel

    PubMed Central

    Latorre, Ramon; Morera, Francisco J; Zaelzer, Cristian

    2010-01-01

    The high conductance voltage- and Ca2+-activated K+ channel is one of the most broadly expressed channels in mammals. This channel is named BK for ‘big K’ because of its single-channel conductance that can be as large as 250 pS in 100 mm symmetrical K+. BK channels increase their activity by membrane depolarization or an increase in cytosolic Ca2+. One of the key features that defines the behaviour of BK channels is that neither Ca2+ nor voltage is strictly necessary for channel activation. This and several other observations led to the idea that both Ca2+ and voltage increase the open probability by an allosteric mechanism. In this type of mechanism, the processes of voltage sensor displacement, Ca2+ binding and pore opening are independent equilibria that interact allosterically with each other. These allosteric interactions in BK channels reside in the structural characteristics of the BK channel in the sense that voltage and Ca2+ sensors and the pore need to be contained in different structures or ‘modules’. Through electrophysiological, mutagenesis, biochemical and fluorescence studies these modules have been identified and, more important, some of the interactions between them have been unveiled. In this review, we have covered the main advances achieved during the last few years in the elucidation of the structure of the BK channel and how this is related with its function as an allosteric protein. PMID:20603335

  19. 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

    2016-02-01

    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. PMID:26757096

  20. Exploring the nature of interactions among thiophene, thiophene sulfone, dibenzothiophene, dibenzothiophene sulfone and a pyridinium-based ionic liquid.

    PubMed

    Gu, Peng; Lü, Renqing; Liu, Dong; Lu, Yukun; Wang, Shutao

    2014-06-14

    In order to gain an understanding of the nature of the interactions among thiophene (TS), thiophene sulfone (TSO2), dibenzothiophene (DBT), dibenzothiophene sulfone (DBTO2) and the ionic liquid N-butylpyridinium hydrogen sulfate ([BPY][HSO4]), a systematic investigation has been carried out using ab initio methods. The most stable structures indicate that both [BPY](+) and [HSO4](-) play crucial roles in the interactions between TS, TSO2, DBT, DBTO2 and [BPY][HSO4]. Analyses of the most stable optimized structures suggest the occurrence of steric effects, π-π stacking effects, hydrogen bonds, and dihydrogen bonds. The π-π stacking effect in [BPY][HSO4]-TSO2/[BPY][HSO4]-DBTO2 is less significant than that in [BPY][HSO4]-TS/[BPY][HSO4]-DBT, as TSO2 and DBTO2 are more nucleophilic than TS and DBT, resulting in stronger interactions between [BPY][HSO4] and TSO2/DBTO2 than between [BPY][HSO4] and TS/DBT. Thermodynamical data also demonstrate that TSO2/DBTO2 are more prone to interact with [BPY][HSO4] compared with TS/DBT. PMID:24741670

  1. 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. PMID:26313181

  2. Experimental Insights on Natural Lava-Ice/Snow Interactions and Their Implications for Glaciovolcanic and Submarine Eruptions

    NASA Astrophysics Data System (ADS)

    Edwards, B. R.; Karson, J.; Wysocki, R.; Lev, E.; Bindeman, I. N.; Kueppers, U.

    2012-12-01

    Lava-ice-snow interactions have recently gained global attention through the eruptions of ice-covered volcanoes, particularly from Eyjafjallajokull in south-central Iceland, with dramatic effects on local communities and global air travel. However, as with most submarine eruptions, direct observations of lava-ice/snow interactions are rare. Only a few hundred potentially active volcanoes are presently ice-covered, these volcanoes are generally in remote places, and their associated hazards make close observation and measurements dangerous. Here we report the results of the first large-scale experiments designed to provide new constraints on natural interactions between lava and ice/snow. The experiments comprised controlled effusion of tens of kilograms of melted basalt on top of ice/snow, and provide insights about observations from natural lava-ice-snow interactions including new constraints for: 1) rapid lava advance along the ice-lava interface; 2) rapid downwards melting of lava flows through ice; 3) lava flow exploitation of pre-existing discontinuities to travel laterally beneath and within ice; and 4) formation of abundant limu o Pele and non-explosive vapor transport from the base to the top of the lava flow with minor O isotope exchange. The experiments are consistent with observations from eruptions showing that lava is more efficient at melting ice when emplaced on top of the ice as opposed to beneath the ice, as well as the efficacy of tephra cover for slowing melting. The experimental extrusion rates are as within the range of those for submarine eruptions as well, and reproduce some features seen in submarine eruptions including voluminous production of gas rich cavities within initially anhydrous lavas and limu on lava surfaces. Our initial results raise questions about the possibility of secondary ingestion of water by submarine and glaciovolcanic lava flows, and the origins of apparent primary gas cavities in those flows. Basaltic melt moving down

  3. Interactions of non-natural halogenated substrates with D-specific dehalogenase (DehD) mutants using in silico studies

    PubMed Central

    Sudi, Ismaila Yada; Shamsir, Mohd Shahir; Jamaluddin, Haryati; Wahab, Roswanira Abdul; Huyop, Fahrul

    2014-01-01

    The D-2-haloacid dehalogenase of D-specific dehalogenase (DehD) from Rhizobium sp. RC1 catalyses the hydrolytic dehalogenation of D-haloalkanoic acids, inverting the substrate-product configuration and thereby forming the corresponding L-hydroxyalkanoic acids. Our investigations were focused on DehD mutants: R134A and Y135A. We examined the possible interactions between these mutants with haloalkanoic acids and characterized the key catalytic residues in the wild-type dehalogenase, to design dehalogenase enzyme(s) with improved potential for dehalogenation of a wider range of substrates. Three natural substrates of wild-type DehD, specifically, monochloroacetate, monobromoacetate and D,L-2,3-dichloropropionate, and eight other non-natural haloalkanoic acids substrates of DehD, namely, L-2-chloropropionate; L-2-bromopropionate; 2,2-dichloropropionate; dichloroacetate; dibromoacetate; trichloroacetate; tribromoacetate; and 3-chloropropionate, were docked into the active site of the DehD mutants R134A and Y135A, which produced altered catalytic functions. The mutants interacted strongly with substrates that wild-type DehD does not interact with or degrade. The interaction was particularly enhanced with 3-chloropropionate, in addition to monobromoacetate, monochloroacetate and D,L-2,3-dichloropropionate. In summary, DehD variants R134A and Y135A demonstrated increased propensity for binding haloalkanoic acid and were non-stereospecific towards halogenated substrates. The improved characteristics in these mutants suggest that their functionality could be further exploited and harnessed in bioremediations and biotechnological applications. PMID:26019583

  4. Physicochemical nature of interfaces controlling ferredoxin NADP(+) reductase activity through its interprotein interactions with ferredoxin.

    PubMed

    Kinoshita, Misaki; Kim, Ju Yaen; Kume, Satoshi; Sakakibara, Yukiko; Sugiki, Toshihiko; Kojima, Chojiro; Kurisu, Genji; Ikegami, Takahisa; Hase, Toshiharu; Kimata-Ariga, Yoko; Lee, Young-Ho

    2015-10-01

    Although acidic residues of ferredoxin (Fd) are known to be essential for activities of various Fd-dependent enzymes, including ferredoxin NADP(+) reductase (FNR) and sulfite reductase (SiR), through electrostatic interactions with basic residues of partner enzymes, non-electrostatic contributions such as hydrophobic forces remain largely unknown. We herein demonstrated that intermolecular hydrophobic and charge-charge interactions between Fd and enzymes were both critical for enzymatic activity. Systematic site-directed mutagenesis, which altered physicochemical properties of residues on the interfaces of Fd for FNR /SiR, revealed various changes in activities of both enzymes. The replacement of serine 43 of Fd to a hydrophobic residue (S43W) and charged residue (S43D) increased and decreased FNR activity, respectively, while S43W showed significantly lower SiR activity without affecting SiR activity by S43D, suggesting that hydrophobic and electrostatic interprotein forces affected FNR activity. Enzyme kinetics revealed that changes in FNR activity by mutating Fd correlated with Km, but not with kcat or activation energy, indicating that interprotein interactions determined FNR activity. Calorimetry-based binding thermodynamics between Fd and FNR showed different binding modes of FNR to wild-type, S43W, or S43D, which were controlled by enthalpy and entropy, as shown by the driving force plot. Residue-based NMR spectroscopy of (15)N FNR with Fds also revealed distinct binding modes of each complex based on different directions of NMR peak shifts with similar overall chemical shift differences. We proposed that subtle adjustments in both hydrophobic and electrostatic forces were critical for enzymatic activity, and these results may be applicable to protein-based electron transfer systems. PMID:26087388

  5. 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

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

    PubMed

    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 (Ca(2+) 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

  7. Numerical Modeling of Hydraulic Fractures Interaction in Complex Naturally Fractured Formations

    NASA Astrophysics Data System (ADS)

    Kresse, Olga; Weng, Xiaowei; Gu, Hongren; Wu, Ruiting

    2013-05-01

    A recently developed unconventional fracture model (UFM) is able to simulate complex fracture network propagation in a formation with pre-existing natural fractures. A method for computing the stress shadow from fracture branches in a complex hydraulic fracture network (HFN) based on an enhanced 2D displacement discontinuity method with correction for finite fracture height is implemented in UFM and is presented in detail including approach validation and examples. The influence of stress shadow effect from the HFN generated at previous treatment stage on the HFN propagation and shape at new stage is also discussed.

  8. Rethinking remediation technologies for desertified landscapes

    SciTech Connect

    Herrick, J.E.; Havstad, K.M.; Coffin, D.P.

    1997-07-01

    Shrub-dominated communities have replaced native grasslands throughout much of the arid Southwest during the past 120 years. Most currently available remediation technologies are uneconomical due to large inputs of energy, fertilizers, herbicides and labor, or are ecologically ineffective due to harsh environments and the highly competitive nature of these native shrubs. Our analysis of these historical remediation technologies together with new information on ecosystem processes has led us to pursue an ecologically-based approach in which more limited inputs are targeted to promote natural processes of regeneration. Advantages to this approach include lower costs, reduced reliance on agronomic practices, and maintenance of natural landscape features. Disadvantages include longer time required for desired changes to occur, and a need for increased understanding of arid land processes.

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

    SciTech Connect

    Vallis, Geoffrey K.

    2015-02-01

    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. 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.

  11. Nature of the collapse transition in interacting self-avoiding trails

    NASA Astrophysics Data System (ADS)

    Oliveira, Tiago J.; Stilck, Jürgen F.

    2016-01-01

    We study the interacting self-avoiding trail (ISAT) model on a Bethe lattice of general coordination q and on a Husimi lattice built with squares and coordination q =4 . The exact grand-canonical solutions of the model are obtained, considering that up to K monomers can be placed on a site and associating a weight ωi with an i -fold visited site. Very rich phase diagrams are found with nonpolymerized, regular polymerized, and dense polymerized phases separated by lines (or surfaces) of continuous and discontinuous transitions. For a Bethe lattice with q =4 and K =2 , the collapse transition is identified with a bicritical point and the collapsed phase is associated with the dense polymerized (solidlike) phase instead of the regular polymerized (liquidlike) phase. A similar result is found for the Husimi lattice, which may explain the difference between the collapse transition for ISATs and for interacting self-avoiding walks on the square lattice. For q =6 and K =3 (studied on the Bethe lattice only), a more complex phase diagram is found, with two critical planes and two coexistence surfaces, separated by two tricritical and two critical end-point lines meeting at a multicritical point. The mapping of the phase diagrams in the canonical ensemble is discussed and compared with simulational results for regular lattices.

  12. Nature of the collapse transition in interacting self-avoiding trails.

    PubMed

    Oliveira, Tiago J; Stilck, Jürgen F

    2016-01-01

    We study the interacting self-avoiding trail (ISAT) model on a Bethe lattice of general coordination q and on a Husimi lattice built with squares and coordination q=4. The exact grand-canonical solutions of the model are obtained, considering that up to K monomers can be placed on a site and associating a weight ω_{i} with an i-fold visited site. Very rich phase diagrams are found with nonpolymerized, regular polymerized, and dense polymerized phases separated by lines (or surfaces) of continuous and discontinuous transitions. For a Bethe lattice with q=4 and K=2, the collapse transition is identified with a bicritical point and the collapsed phase is associated with the dense polymerized (solidlike) phase instead of the regular polymerized (liquidlike) phase. A similar result is found for the Husimi lattice, which may explain the difference between the collapse transition for ISATs and for interacting self-avoiding walks on the square lattice. For q=6 and K=3 (studied on the Bethe lattice only), a more complex phase diagram is found, with two critical planes and two coexistence surfaces, separated by two tricritical and two critical end-point lines meeting at a multicritical point. The mapping of the phase diagrams in the canonical ensemble is discussed and compared with simulational results for regular lattices. PMID:26871113

  13. 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…

  14. 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…

  15. 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…

  16. Revisiting and Rethinking the Reading Process.

    ERIC Educational Resources Information Center

    Kucer, Stephen B.; Tuten, Jenny

    2003-01-01

    Reports on the authors' revisiting of the reading process using proficient adult readers (advanced graduate students in a school of education) as their informants. Begins with a brief overview of the current debate concerning the nature of reading and explains how they went about investigating the issue. Discusses what they learned from their…

  17. 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…

  18. A Dialectical Approach to Rethinking Roommate Relationships

    ERIC Educational Resources Information Center

    Hanasono, Lisa K.; Nadler, Lawrence B.

    2012-01-01

    Previous research on the complex interplay between roommate factors and relational satisfaction has offered contradictory findings. This study establishes a typology that accounts for relational satisfaction among first-year college roommates. Drawing from the theoretical framework of Interactional Dialectics and the ideal hypothesis, three…

  19. 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…

  20. Inside School Spaces: Rethinking the Hidden Dimension.

    ERIC Educational Resources Information Center

    Sitton, Thad

    1980-01-01

    Considers the spatial arrangements of public schools as culturally derived characteristics that reflect particular traditional expectations in regard to the learning process and teacher student interactions. Discusses fixed spatial arrangements as well as the territorial manipulation of school space by students. (GC)

  1. 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. PMID:26403389

  2. 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. PMID:26001280

  3. 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.

  4. 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. PMID:24879687

  5. 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. PMID:26860863

  6. 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

    2015-07-01

    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 sampled dwellings

  7. Interaction of antitumor alpha-lactalbumin-oleic acid complexes with artificial and natural membranes.

    PubMed

    Zherelova, Olga M; Kataev, Anatoly A; Grishchenko, Valery M; Knyazeva, Ekaterina L; Permyakov, Sergei E; Permyakov, Eugene A

    2009-06-01

    The specific complexes of human alpha-lactalbumin (alpha-LA) with oleic acid (OA), HAMLET and LA-OA-17 (OA-complexes), possess cytotoxic activity against tumor cells but the mechanism of their cell penetration remains unclear. To explore the molecular mechanisms underlying interaction of the OA-complexes with the cell membrane, their interactions with small unilamellar dipalmitoylphosphatidylcholine (DPPC) vesicles and electroexcitable plasma membrane of internodal native and perfused cells of the green alga Chara corallina have been studied. The fractionation (Sephadex G-200) of mixtures of the OA-complexes with the vesicles shows that OA-binding increases the affinity of alpha-LA to DPPC vesicles. Calcium association decreases protein affinity to the vesicles; the effect being less pronounced for LA-OA-17. The voltage clamp technique studies show that LA-OA-17, HAMLET, and their constituents produce different modifying effects on the plasmalemmal ionic channels of the Chara corallina cells. The irreversible binding of OA-complexes to the plasmalemma is accompanied by changes in the activation-inactivation kinetics of developing integral transmembrane currents, suppression of the Ca(2+) current and Ca(2+)-activated Cl(-) current, and by increase in the nonspecific K(+) leakage currents. The latter reflects development of nonselective permeability of the plasma membrane. The HAMLET-induced effects on the plasmalemmal currents are less pronounced and potentiated by LA-OA-17. The control experiments with OA and intact alpha-LA show their qualitatively different and much less pronounced effects on the transmembrane ionic currents. Thus, the modification of alpha-LA by OA results in an increase in the protein association with the model lipid bilayer and in drastic irreversible changes in permeability of several types of the plasmalemmal ionic channels. PMID:19588235

  8. 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.

  9. 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

  10. 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

  11. Interaction of Glucagon G-Protein Coupled Receptor with Known Natural Antidiabetic Compounds: Multiscoring In Silico Approach

    PubMed Central

    Baig, M. H.; Ahmad, K.; Hasan, Q.; Khan, M. K. A.; Rao, N. S.; Kamal, M. A.; Choi, I.

    2015-01-01

    Glucagon receptor (GCGR) is a secretin-like (class B) family of G-protein coupled receptors (GPCRs) in humans that plays an important role in elevating the glucose concentration in blood and has thus become one of the promising therapeutic targets for treatment of type 2 diabetes mellitus. GCGR based inhibitors for the treatment of type 2 diabetes are either glucagon neutralizers or small molecular antagonists. Management of diabetes without any side effects is still a challenge to the medical system, and the search for a new and effective natural GCGR antagonist is an important area for the treatment of type 2 diabetes. In the present study, a number of natural compounds containing antidiabetic properties were selected from the literature and their binding potential against GCGR was determined using molecular docking and other in silico approaches. Among all selected natural compounds, curcumin was found to be the most effective compound against GCGR followed by amorfrutin 1 and 4-hydroxyderricin. These compounds were rescored to confirm the accuracy of binding using another scoring function (x-score). The final conclusions were drawn based on the results obtained from the GOLD and x-score. Further experiments were conducted to identify the atomic level interactions of selected compounds with GCGR. PMID:26236379

  12. Interaction of Aβ(25-35) fibrillation products with mitochondria: Effect of small-molecule natural products.

    PubMed

    Ghobeh, Maryam; Ahmadian, Shahin; Meratan, Ali Akbar; Ebrahim-Habibi, Azadeh; Ghasemi, Atiyeh; Shafizadeh, Mahshid; Nemat-Gorgani, Mohsen

    2014-11-01

    The 25-35 fragment of the amyloid β (Aβ) peptide is a naturally occurring proteolytic by-product that retains the pathophysiology of its larger parent molecule, whose deposition has been shown to involve mitochondrial dysfunction. Hence, disruption of Aβ(25-35) aggregates could afford an effective remedial strategy for Alzheimer's disease (AD). In the present study, the effect of a number of selected small-molecule natural products (polyphenols: resveratrol, quercetin, biochanin A, and indoles: indole-3-acetic acid, indole-3-carbinol (I3C)) on Aβ(25-35) fibrillogenesis was explored under physiological conditions, and interaction of the resulting structures with rat brain mitochondria was investigated. Several techniques, including fluorescence, circular dichroism, and transmission electron microscopy were utilized to characterize the aggregation products, and possible mitochondrial membrane permeabilization was determined following release of marker enzymes. Results demonstrate the capacity of Aβ(25-35) fibrils to damage mitochondria and suggest how small molecules may afford protection. While I3C appeared more effective in inhibiting the fibrillation process, all natural products behaved similarly in destabilizing preformed aggregates. It is concluded that elucidation of such protection may provide important insights into the development of preventive and therapeutic agents for AD. PMID:25297917

  13. 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.

  14. 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. PMID:27130653

  15. Representing Nature of Science in a Science Textbook: Exploring author-editor-publisher interactions

    NASA Astrophysics Data System (ADS)

    DiGiuseppe, Maurice

    2014-05-01

    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 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 NOS; squared these with mandated curricula, the educational needs of chemistry students and teachers, and the exigencies of large-scale commercial textbook publishing. As a result, the team developed and incorporated, in the textbook, representations of NOS they believed were the most pedagogically suitable. Analysis of the data in this study indicates that a number of factors significantly influenced the development of representations of NOS, including representational accuracy (the degree to which representations of NOS conformed to informed views of the NOS), representational consistency (the degree to which representations of NOS in different parts of the book conveyed the same meaning), representational appropriateness (the age-, grade-, and reading-level appropriateness of the NOS representations), representational alignment (the degree to which NOS representations aligned with mandated curriculum), representational marketability (the degree to which NOS representations would affect sales of the textbook), and 'Workplace Resources' factors including availability of time, relevant expertise, and opportunities for professional development.

  16. Transmembrane transport of steviol glucuronide and its potential interaction with selected drugs and natural compounds.

    PubMed

    Wang, Meiyu; Qi, Huixin; Li, Jiajun; Xu, Yunting; Zhang, Hongjian

    2015-12-01

    Steviol glucuronide (SVG) is the major metabolite derived from steviol, the aglycone of stevioside and rebaudioside A. After the ingestion of stevioside and rebaudioside A, SVG is formed and excreted into the urine in humans. In the present study, transporter mediated efflux and uptake of SVG was investigated in order to understand molecular mechanisms underlying its renal clearance. Results showed that SVG was not a substrate of efflux transporters BCRP, MRP2, MATE1 or P-gp. In contrast, OAT3 played a predominant role in the uptake of SVG in comparison to OATP1B1, OATP1B3, or OATP2B1. Quercetin, telmisartan, diclofenac, and mulberrin displayed a relatively strong inhibition against OAT3 mediated uptake of SVG with IC50 values of 1.8, 2.9, 8.0, and 10.0 μM, respectively. Because OAT3 is a major uptake transporter in the kidney, inhibition of OAT3 activity may alter SVG's renal clearance by drugs and natural compounds that are used concomitantly with stevia leaf extracts. PMID:26525112

  17. Interactions between chensinin-1, a natural antimicrobial peptide derived from Rana chensinensis, and lipopolysaccharide.

    PubMed

    Dong, Weibing; Sun, Yue; Shang, Dejing

    2015-12-01

    Lipopolysaccharide (LPS) plays a critical role in the pathogenesis of sepsis caused by gram-negative bacterial infections. Therefore, LPS-neutralizing molecules would have important clinical applications. Chensinin-1, a novel antimicrobial peptide with atypical structural features, was found in the skin secretions of the Chinese brown frog Rana chensinensis. To understand the role of LPS in the bacterial susceptibility to chensinin-1 and to investigate its anti-endotoxin effects, the interactions of chensinin-1 with LPS were investigated in this study using circular dichroism, in situ IR, isothermal titration calorimetry, and zeta potential. This study is the first to use in situ IR spectroscopy to evaluate the secondary structural changes of this peptide. The capacity of chensinin-1 to block the LPS-dependent cytokine secretion of macrophages was also investigated. Our results show that chensinin-1 can form α-helical structures in LPS suspensions. LPS can affect the antimicrobial activity of chensinin-1, and chensinin-1 was able to mitigate the effects of LPS. These data may facilitate the development of antimicrobial peptides with potent antimicrobial and anti-endotoxin activities. PMID:26340228

  18. 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.

  19. Benzene dispersion and natural attenuation in an alluvial aquifer with strong interactions with surface water

    NASA Astrophysics Data System (ADS)

    Batlle-Aguilar, Jordi; Brouyère, Serge; Dassargues, Alain; Morasch, Barbara; Hunkeler, Daniel; Höhener, Patrick; Diels, Ludo; Vanbroekhoven, Karolien; Seuntjens, Piet; Halen, Henri

    2009-05-01

    levels, leading to the hypothesis that benzene dispersion is mainly controlled by natural attenuation.

  20. Interactions between radioactively labeled colloids and natural particles: Evidence for colloidal pumping

    SciTech Connect

    Wen, L.S.; Santschi, P.H.; Tang, D.

    1997-07-01

    It has been hypothesized that colloidal forms of trace metals can be reactive intermediaries in the scavenging processes leading to the removal of their particulate forms. A series of radiotracer experiments using natural colloidal organic matter from Galveston Bay, USA were carried out in order to test this hypothesis. Suspended particle uptake of originally colloidally bound trace metals occurred in a matter of hours to days in estuarine waters. After ten days, the majority ( >50%) of the colloidal trace metals had been transferred into the particulate phase ({ge} 0.45{mu}m), except for {sup 65}Zn. Two distinctively different temporal regions of removal of colloidal trace metals were identified: a faster reaction during the first four hours, followed by a slower reaction after approximately one day. In a separate river water-seawater mixing experiment, the solid/solution partitioning of the radiotracers was investigated in the absence of suspended matter. About 30% of most of the elements, except Ag and Fe ({approximately}60%), were associated with a newly formed particulate phase after eight days. There were two major trends: (1) the particulate fraction of {sup 59}Fe and {sup 110}Ag increased while the colloidal fraction decreased, suggesting a colloidal pumping mechanism. (2) The particulate fraction of {sup 54}Mn, {sup 133}Ba, {sup 65}Zn, {sup 109}Cd, {sup 113}Sn, and {sup 60}Co increased while the LMW({le}1 kDa) fraction decreased, suggesting a direct uptake into the particulate fraction with less involvement of a transitory colloidal phase. The results from these experiments suggested two different pathways for colloidal tracer uptake by particles: (1) colloidal pumping of a major component (e.g., biopolymer) of the colloidal pool and (2) coagulation of trace components (e.g., phytochelatins) with varying affinities for different trace metals. 39 refs., 8 figs., 3 tabs.

  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. 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. PMID:26988233

  3. Platelet activation and platelet-leukocyte interaction in dogs naturally infected with Babesia rossi.

    PubMed

    Goddard, Amelia; Leisewitz, Andrew L; Kristensen, Annemarie T; Schoeman, Johan P

    2015-09-01

    Using flow cytometry, platelet-leukocyte aggregate (PLA) formation has previously been documented in dogs with a variety of systemic inflammatory disorders and immune-mediated haemolytic anaemia. Platelet activation and subsequent interaction between platelets and leukocytes are important for regulating innate immunity and systemic inflammation. The objective of this study was to investigate PLA formation in canine babesiosis and to determine whether it was associated with outcome. Blood was collected from 36 client-owned dogs diagnosed with Babesia rossi infection and 15 healthy controls using EDTA as anticoagulant. Activated platelets and PLA formation were detected by measuring surface expression of P-selectin (CD62P) on platelets, monocytes and neutrophils. Of the Babesia-infected dogs, 29 survived and seven died. The percentage of CD62P-positive monocytes was significantly higher (P = 0.036) in the Babesia-infected dogs (54%) than in healthy control dogs (35.3%). However, there were no significant differences between the Babesia-infected and control groups for CD62P-positive platelets (4.9% and 1.2%, respectively) and CD62P-positive neutrophils (28.3% and 17.9%, respectively). The percentage of CD62P-positive monocytes was significantly higher (P = 0.019) in the survivors (58.9%) than in healthy control dogs; however, there were no significant differences between the non-survivors (39.2%) and the controls or between survivors and non-survivors. There were no significant differences between groups for the percentage of CD62P-positive platelets (survivors 4.8%; non-survivors 5.3%; controls 1.2%) or CD62P-positive neutrophils (survivors 31.6%; non-survivors 5.6%; controls 17.9%). In conclusion, Babesia-infected dogs, specifically dogs that survived, had a significantly increased percentage of platelet-monocyte aggregates compared to healthy control dogs. PMID:26088270

  4. 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.

  5. 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.

  6. Differences in the nature of the interaction of insulin and proinsulin with zinc

    PubMed Central

    Grant, P. T.; Coombs, T. L.; Frank, B. H.

    1972-01-01

    1. The reversible interaction of zinc with pig insulin and proinsulin has been studied at pH7 by equilibrium dialysis (ultrafiltration) and by sedimentation equilibrium and velocity measurements in the ultracentrifuge. Binding values calculated from equilibria, where the ratio of free to bound zinc was varied in the range 0.01:1–10:1, indicated that proinsulin and insulin each contained two main orders of zinc binding with very different affinities for the metal. 2. In equilibria containing low concentrations of free zinc (free: bound ratios of 0.01–0.1:1) both insulin and proinsulin aggregated to form soluble hexamers containing firmly bound zinc (up to 0.284g-atom/monomer) with an apparent intrinsic association constant of 1.9×106m−1. 3. Higher concentrations of zinc (free: bound ratios of 0.1–10.0:1) resulted in a progressive difference in the zinc binding, aggregation and solubility properties of the metal complexes of insulin and proinsulin. At the highest concentration of free zinc, proinsulin bound a total of more than 5.0g-atom/monomer and aggregated to form a mixture of soluble polymers (mainly 5.1S). In contrast, insulin bound a total of only 1.0g-atom/monomer and was almost completely precipitated from solution. 4. These results would indicate that the presence of the peptide segment connecting the insulin moiety in proinsulin does not prevent the firm binding of zinc to the insulin moiety and the formation of hexamers of zinc–proinsulin. At the same time although the connecting peptide contains additional sites of lower affinity for zinc, which should facilitate inter- and intra-molecular cross-linking, the general conformation of the zinc–proinsulin hexamer must preclude the formation of very large and close-packed aggregates that are insoluble in solutions at equilibrium. PMID:5062309

  7. 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

  8. Rethinking cumulative exposure in epidemiology, again.

    PubMed

    de Vocht, Frank; Burstyn, Igor; Sanguanchaiyakrit, Nuthchyawach

    2015-01-01

    The use of cumulative exposure, the product of intensity and duration, has enjoyed great popularity in epidemiology of chronic diseases despite numerous known caveats in its interpretation. We briefly review the history of use of cumulative exposure in epidemiology and propose an alternative method for relating time-integrated exposures to health risks. We argue, as others before us have, that cumulative exposure metrics obscures the interplay of exposure intensity and duration. We propose to use a computationally simple alternative in which duration and intensity of exposure are modelled as a main effect and their interaction, cumulative exposure, only be added if there is evidence of deviation from this additive model. We also consider the Lubin-Caporaso model of interplay of exposure intensity and duration. The impact of measurement error in intensity on model selection was also examined. The value of this conceptualization is demonstrated using a simulation study and further illustrated in the context of respiratory health and occupational exposure to latex dust. We demonstrate why cumulative exposure has been so popular because the cumulative exposure metric per se gives a robust answer to the existence of an association, regardless of the underlying true mechanism of disease. Treating cumulative exposure as the interaction of main effects of exposure duration and intensity enables epidemiologists to derive more information about mechanism of disease then fitting cumulative exposure metric by itself, and without the need to collect additional data. We propose that the practice of fitting duration, intensity and cumulative exposure separately to epidemiologic data should lead to conceptualization of cumulative exposure as interaction of main effects of duration and intensity of exposure. PMID:25138292

  9. 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

  10. 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…

  11. 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

  12. Social media and medical professionalism: rethinking the debate and the way forward.

    PubMed

    Fenwick, Tara

    2014-10-01

    This Perspective addresses the growing literature about online medical professionalism. Whereas some studies point to the positive potential of social media to enhance and extend medical practice, the dominant emphasis is on the risks and abuses of social media. Overall evidence regarding online medical professionalism is (as with any new area of practice) limited; however, simply accumulating more evidence, without critically checking the assumptions that frame the debate, risks reinforcing negativity toward social media. In this Perspective, the author argues that the medical community should step back and reconsider its assumptions regarding both professionalism and the digital world of social media. Toward this aim, she outlines three areas for critical rethinking by educators and students, administrators, professional associations, and researchers. First she raises some cautions regarding the current literature on using social media in medical practice, which sometimes leaps too quickly from description to prescription. Second, she discusses professionalism. Current debates about the changing nature and contexts of professionalism generally might be helpful in reconsidering notions of online medical professionalism specifically. Third, the author argues that the virtual world itself and its built-in codes deserve more critical scrutiny. She briefly summarizes new research from digital studies both to situate the wider trends more critically and to appreciate the evolving implications for medical practice. Next, the author revisits the potential benefits of social media, including their possibilities to signal new forms of professionalism. Finally, the Perspective ends with specific suggestions for further research that may help move the debate forward. PMID:25076200

  13. A depth camera for natural human-computer interaction based on near-infrared imaging and structured light

    NASA Astrophysics Data System (ADS)

    Liu, Yue; Wang, Liqiang; Yuan, Bo; Liu, Hao

    2015-08-01

    Designing of a novel depth camera is presented, which targets close-range (20-60cm) natural human-computer interaction especially for mobile terminals. In order to achieve high precision through the working range, a two-stepping method is employed to match the near infrared intensity image to absolute depth in real-time. First, we use structured light achieved by an 808nm laser diode and a Dammann grating to coarsely quantize the output space of depth values into discrete bins. Then use a learning-based classification forest algorithm to predict the depth distribution over these bins for each pixel in the image. The quantitative experimental results show that this depth camera has 1% precision over range of 20-60cm, which show that the camera suit resource-limited and low-cost application.

  14. 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

  15. Rethinking the surface of optical waveguides

    NASA Astrophysics Data System (ADS)

    Melati, D.; Morichetti, F.; Grillanda, S.; Annoni, A.; Melloni, A.

    2015-05-01

    The interface between the core and the cladding of optical waveguides exhibits a number of physical phenomena that do not occur in the bulk of the material. For this reason, the behavior of nanoscale devices is expected to be conditioned, or even dominated, by the nature of their surfaces. Roughness-induced losses, backscattering and crosstalk between adjacent waveguides, together with surface states absorption impact on the optical and electrical properties of the waveguides must be considered in the design of any integrated optoelectronic device. The detrimental effects and the possibility of their exploitation are carefully reviewed, presenting in particular the ContacLess Integrated Photonic Probe to be used as transparent power monitor.

  16. 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

  17. 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

  18. 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. PMID:27146283

  19. 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.

  20. 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

  1. Interactions Between Mathematics and Physics: The History of the Concept of Function—Teaching with and About Nature of Mathematics

    NASA Astrophysics Data System (ADS)

    Kjeldsen, Tinne Hoff; Lützen, Jesper

    2015-07-01

    In this paper, we discuss the history of the concept of function and emphasize in particular how problems in physics have led to essential changes in its definition and application in mathematical practices. Euler defined a function as an analytic expression, whereas Dirichlet defined it as a variable that depends in an arbitrary manner on another variable. The change was required when mathematicians discovered that analytic expressions were not sufficient to represent physical phenomena such as the vibration of a string (Euler) and heat conduction (Fourier and Dirichlet). The introduction of generalized functions or distributions is shown to stem partly from the development of new theories of physics such as electrical engineering and quantum mechanics that led to the use of improper functions such as the delta function that demanded a proper foundation. We argue that the development of student understanding of mathematics and its nature is enhanced by embedding mathematical concepts and theories, within an explicit-reflective framework, into a rich historical context emphasizing its interaction with other disciplines such as physics. Students recognize and become engaged with meta-discursive rules governing mathematics. Mathematics teachers can thereby teach inquiry in mathematics as it occurs in the sciences, as mathematical practice aimed at obtaining new mathematical knowledge. We illustrate such a historical teaching and learning of mathematics within an explicit and reflective framework by two examples of student-directed, problem-oriented project work following the Roskilde Model, in which the connection to physics is explicit and provides a learning space where the nature of mathematics and mathematical practices are linked to natural science.

  2. Autoreactive natural killer T cells: promoting immune protection and immune tolerance through varied interactions with myeloid antigen-presenting cells

    PubMed Central

    Hegde, Subramanya; Fox, Lisa; Wang, Xiaohua; Gumperz, Jenny E

    2010-01-01

    Natural killer T (NKT) cells are innate T lymphocytes that are restricted by CD1d antigen-presenting molecules and recognize lipids and glycolipids as antigens. NKT cells have attracted attention for their potent immunoregulatory effects. Like other types of regulatory lymphocytes, a high proportion of NKT cells appear to be autoreactive to self antigens. Thus, as myeloid antigen-presenting cells (APCs) such as monocytes, dendritic cells (DCs) and myeloid-derived suppressor cells (MDSCs) constitutively express CD1d, NKT cells are able to interact with these APCs not only during times of immune activation but also in immunologically quiescent periods. The interactions of NKT cells with myeloid APCs can have either pro-inflammatory or tolerizing outcomes, and a central question is how the ensuing response is determined. Here we bring together published results from a variety of model systems to highlight three critical factors that influence the outcome of the NKT–APC interaction: (i) the strength of the antigenic signal delivered to the NKT cell, as determined by antigen abundance and/or T-cell receptor (TCR) affinity; (ii) the presence or absence of cytokines that costimulate NKT cells [e.g. interleukin (IL)-12, IL-18 and interferon (IFN)-α]; (iii) APC intrinsic factors such as differentiation state (e.g. monocyte versus DC) and Toll-like receptor (TLR) stimulation. Together with recent findings that demonstrate new links between NKT cell activation and endogenous lipid metabolism, these results outline a picture in which the functions of NKT cells are closely attuned to the existing biological context. Thus, NKT cells may actively promote tolerance until a critical level of danger signals arises, at which point they switch to activating pro-inflammatory immune responses. PMID:20465577

  3. Rethinking the Postgraduate Teaching Program and Examinations in Today's India.

    PubMed

    Abraham, Georgi; George, Tarun K

    2015-07-01

    Postgraduate medical education has undergone drastic changes in the developed and developing countries on par with advancements in technology. The Indian examination system which we imbibed from the British requires a rethinking and restructuring to keep pace with the changing trends shown by the Federation of the Royal Colleges of UK. In this manuscript we look at the strengths and weaknesses of different examination systems. We suggest changes in the theory examination which should be objectively based rather than the outdated essay and short notes. We discuss positive and proactive changes to reform our clinical examination system to enable a just and fair assessment of the candidate in a strictly time bound fashion. PMID:26731837

  4. 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. PMID:18686789

  5. 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.

  6. Matter, metaphors, and mechanisms: rethinking cell theories.

    PubMed

    Müller-Strahl, Gerhard

    2014-12-01

    This study analyzes the logical structure of classical cell theory (CCT) by pointing out that CCT conceives the properties of organic cellular matter as supervenient to successively emerging states of quasi-crystalline atoms. This concept supports the design of a metaphorical space the intelligible components of which display an explanatory structure in accordance with the contemporary complex-systems approach of mechanisms. These findings support the thesis of an explanatory turn within the life-sciences due to a conflict between anti-classificatory (Buffon), analogous (Wolff, Reil, Weber), and causal-mechanical (Kepler) strategies of explanation. The continuous process underlying these diverse discontinuities is taken to be the immanent process of objectifying scientific concepts for the need of explanation. This process repeatedly provides concepts which are identified as nomadic concepts. The meta-analysis of their interactions reveals that concepts of matter are obtained by idealizations which entertain one process with three dimensions: atomization originating from empirical classificatory regularities (classification) and aiming at an explanation of changing phenomena (dynamization). These dimensions are successfully incorporated into the explanatory scheme of CCT. The migrations of a second group of nomadic concepts beyond this historical point of transition are made responsible for blurring the explanatory turn. PMID:25156862

  7. Behavioral externalities in natural resource production possibility frontiers: integrating biology and economics to model human-wildlife interactions.

    PubMed

    McCoy, N H

    2003-09-01

    Production possibility modeling has been applied to a variety of wildlife management issues. Although it has seen only limited employment in modeling human-wildlife output decisions, it can be expected that the theory's use in this area will increase as human interactions with and impacts on wildlife become more frequent. At present, most models applying production possibility theory to wildlife production can be characterized in that wildlife output quantities are determined by physically quantifiable functions representing rivalrous resources. When the theory is applied to human-wildlife interactions, it may not be sufficient to model the production tradeoffs using only physical constraints. As wildlife are known to respond to human presence, it could be expected that human activity may appear in wildlife production functions as an externality. Behavioral externalities are revealed by an output's response to the presence of another output and can result in a loss of concavity of the production possibilities frontier. Ignoring the potential of a behavioral externality can result in an unexpected and inefficient output allocation that may compromise a wildlife population's well-being. Behavioral externalities can be included in PPF models in a number of ways, including the use of data or cumulative effects modeling. While identifying that behavioral externalities exist and incorporating them into a model is important, correctly interpreting their implications will be critical to improve the efficiency of natural resource management. Behavioral externalities may cause a loss of concavity anywhere along a PPF that may compel managerial decisions that are inconsistent with multiple use doctrines. Convex PPFs may result when wildlife species are extremely sensitive to any level of human activity. It may be possible to improve the PPF's concavity by reducing the strength of the behavioral effect. Any change in the PPF that increases the convexity of the production set

  8. 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…

  9. 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

  10. 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

  11. 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

  12. 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.

  13. 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. PMID:23295360

  14. 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.

  15. 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

  16. The Interaction of Telomeric DNA and C-myc22 G-Quadruplex with 11 Natural Alkaloids

    PubMed Central

    Ji, Xiaohui; Sun, Hongxia; Zhou, Huaxi; Xiang, Junfeng

    2012-01-01

    Telomeric DNA and C-myc22 are DNA G-quadruplex (G4)-forming sequences associated with tumorigenesis. Ligands that can facilitate the formation and increase the stabilization of G4 can halt tumor cell proliferation and have been regarded as potential anti-cancer drugs. In the present study, we have investigated the interaction of 11 natural alkaloids with G4 formed by telomeric DNA and C-myc22 sequences. Our results indicated that sanguinarine (San), palmatine (Pal), and berberine (Beb) of the first series (S1) can induce the formation of G4 as well as increase the stabilization ability. Daurisoline (S2-1), O-methyldauricine (S2-2), O-diacetyldaurisoline (S2-3), daurinoline (S2-4), dauricinoline (S2-5), N,N′-dimethyldauricine iodide (S2-6), and N,N′-dimethyldaurisoline iodide (S2-7) of the second series (S2) showed similar stabilization ability. We found that unsaturated ring C, N+ positively charged centers, and conjugated aromatic rings are key factors to increase the stabilization ability of S1, and we gave some advice on structure modification to S2 through structure-activity study. Besides, we found San and Pal to be cell cycle blocker in G1. San was speculated to bind to G4 through intercalation or end stacking. PMID:22480315

  17. CD34+ hematopoietic precursors are present in human decidua and differentiate into natural killer cells upon interaction with stromal cells.

    PubMed

    Vacca, Paola; Vitale, Chiara; Montaldo, Elisa; Conte, Romana; Cantoni, Claudia; Fulcheri, Ezio; Darretta, Valeria; Moretta, Lorenzo; Mingari, Maria Cristina

    2011-02-01

    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) CD56(bright)CD16(-)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

  18. Symmetry structure in discrete models of biochemical systems: natural subsystems and the weak control hierarchy in a new model of computation driven by interactions.

    PubMed

    Nehaniv, Chrystopher L; Rhodes, John; Egri-Nagy, Attila; Dini, Paolo; Morris, Eric Rothstein; Horváth, Gábor; Karimi, Fariba; Schreckling, Daniel; Schilstra, Maria J

    2015-07-28

    Interaction computing is inspired by the observation that cell metabolic/regulatory systems construct order dynamically, through constrained interactions between their components and based on a wide range of possible inputs and environmental conditions. The goals of this work are to (i) identify and understand mathematically the natural subsystems and hierarchical relations in natural systems enabling this and (ii) use the resulting insights to define a new model of computation based on interactions that is useful for both biology and computation. The dynamical characteristics of the cellular pathways studied in systems biology relate, mathematically, to the computational characteristics of automata derived from them, and their internal symmetry structures to computational power. Finite discrete automata models of biological systems such as the lac operon, the Krebs cycle and p53-mdm2 genetic regulation constructed from systems biology models have canonically associated algebraic structures (their transformation semigroups). These contain permutation groups (local substructures exhibiting symmetry) that correspond to 'pools of reversibility'. These natural subsystems are related to one another in a hierarchical manner by the notion of 'weak control'. We present natural subsystems arising from several biological examples and their weak control hierarchies in detail. Finite simple non-Abelian groups are found in biological examples and can be harnessed to realize finitary universal computation. This allows ensembles of cells to achieve any desired finitary computational transformation, depending on external inputs, via suitably constrained interactions. Based on this, interaction machines that grow and change their structure recursively are introduced and applied, providing a natural model of computation driven by interactions. PMID:26078349

  19. 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

  20. 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.

  1. Acceleration of Wound Healing by α-gal Nanoparticles Interacting with the Natural Anti-Gal Antibody

    PubMed Central

    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. PMID:25922849

  2. Nature of hydrogen interactions with Ni(II) complexes containing cyclic phosphine ligands with pendant nitrogen bases

    PubMed Central

    Wilson, Aaron D.; Shoemaker, R. K.; Miedaner, A.; Muckerman, J. T.; DuBois, Daniel L.; DuBois, M. Rakowski

    2007-01-01

    Studies of the role of proton relays in molecular catalysts for the electrocatalytic production and oxidation of H2 have been carried out. The electrochemical production of hydrogen from protonated DMF solutions catalyzed by [Ni(P2PhN2Ph)2(CH3CN)](BF4)2, 3a (where P2PhN2Ph is 1,3,5,7-tetraphenyl-1,5-diaza-3,7-diphosphacyclooctane), permits a limiting value of the H2 production rate to be determined. The turnover frequency of 350 s−1 establishes that the rate of H2 production for the mononuclear nickel catalyst 3a is comparable to those observed for Ni-Fe hydrogenase enzymes. In the electrochemical oxidation of hydrogen catalyzed by [Ni(P2CyN2Bz)2](BF4)2, 3b (where Cy is cyclohexyl and Bz is benzyl), the initial step is the reversible addition of hydrogen to 3b (Keq = 190 atm−1 at 25°C). The hydrogen addition product exists as three nearly isoenergetic isomers 4A–4C, which have been identified by a combination of one- and two-dimensional 1H, 31P, and 15N NMR spectroscopies as Ni(0) complexes with a protonated amine in each cyclic ligand. The nature of the isomers, together with calculations, suggests a mode of hydrogen activation that involves a symmetrical interaction of a nickel dihydrogen ligand with two amine bases in the diphosphine ligands. Single deprotonation of 4 by an external base results in a rearrangement to [HNi(P2CyN2Bz)2](BF4), 5, and this reaction is reversed by the addition of a proton to the nickel hydride complex. The small energy differences associated with significantly different distributions in electron density and protons within these molecules may contribute to their high catalytic activity. PMID:17360385

  3. Heterogeneous nucleation as the predominant mode of crystallization in natural magmas: numerical model and implications for crystal-melt interaction

    NASA Astrophysics Data System (ADS)

    Špillar, Václav; Dolejš, David

    2015-01-01

    Crystallization of natural magmas is inherently a disequilibrium process, which involves nucleation and growth kinetics, melt-crystal mechanical interactions and subsolidus modifications, which are all recorded in the resulting rock texture. We use a new high-resolution three-dimensional numerical model to address the significance and consequences of homogeneous versus heterogeneous crystal nucleation in silicate magmas. With increasing amount of heterogeneous nuclei during crystallization, initially equigranular textures evolve to porphyritic, bimodal and spherulitic types. The corresponding crystal size distributions (CSDs) become concave-up curved, the clustering index progressively decreases, and the grain contact relationships record increased clustering. Concave-up curved CSDs previously interpreted as resulting from multistage crystallization, mixing of crystal populations, grain agglomeration, or size-dependent growth are now predicted, consistently with other size, spatial and clustering parameters, to form by heterogeneous crystal nucleation. Correlation relationships between various textural parameters and the fraction of heterogeneous nuclei are calibrated and used on representative volcanic and plutonic rocks, including cumulate rocks, to deduce the fraction of heterogeneous nuclei. The results indicate that ~60 to ~99 % of all nuclei are heterogeneous. For plutonic and cumulate rocks, the estimate of the heterogeneous nuclei fraction based on the clustering index is significantly lower than other estimates. Such discrepancies, in general, point to the occurrence of other processes, and here, the results imply that crystal-mush compaction and interstitial melt extraction were involved during the magma solidification. Formation of crystals in clusters, implicit for heterogeneous nucleation, implies that greater efficiency of crystal-melt separation is expected in these situations.

  4. Particle-image velocimetry investigation of the fluid-structure interaction mechanisms of a natural owl wing.

    PubMed

    Winzen, A; Roidl, B; Schröder, W

    2015-10-01

    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. PMID:26372422

  5. 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. PMID:25922849

  6. Synthetic and natural compounds that interact with human cytochrome P450 1A2 and implications in drug development.

    PubMed

    Wang, Bo; Zhou, Shu-Feng

    2009-01-01

    Human cytochrome P450 1A2 (CYP1A2) is one of the major CYPs in the liver ( approximately 13%) and metabolizes about 20% of clinically used drugs. CYP1A2 is a 515-residue protein with a molecular mass of 58,294 Dal. The recently published crystal structure of CYP1A2 in complex with alpha-naphthoflavone has showed a rather compact active site with a relatively small volume of the cavity of 375 A(3), which is 44.2% and 49.3% larger than that of CYP2A6 (260 A(3)) and CYP2E1 (190 A(3)), respectively. A series of residues in the substrate recognition regions of CYP1A2 (e.g. Arg108, Thr124, Thr223, Glu225, Phe226, Lys250, Arg251, Lys253, Asn312, Asp313, Glu318, Thr319, Asp320, Thr321, Val322, Leu382, Thr385, and Ile386) have been shown to play important roles in ligand-enzyme binding based on site-directed mutagenesis and homology modeling studies. Typical CYP1A2 substrates generally contain planar ring that can fit the narrow and planar active site of the enzyme, such as propranolol, clozapine, guanabenz, flutamide, imatinib, thalidomide, carbamazepine, lidocaine, theophylline, tacrine, tizanidine, zolpidem, riluzole, zileuton, and leflunomide. CYP1A2 is one of the major enzymes that bioactivate a number of procarcinogens including polycyclic aromatic hydrocarbons (e.g., benzo[a]pyrene), heterocyclic aromatic amines/amides (e.g. 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), mycotoxins (e.g. aflatoxin B(1)) and some natural compounds such as aristolochic acids present in several Chinese herbal medicines. This enzyme also metabolizes several important endogenous compounds including retinols, melatonin, steroids, uroporphyrinogen and arachidonic acids. Like many of other CYPs, CYP1A2 is subject to induction and inhibition by a number of compounds. In particular, several therapeutic drugs including antofloxacin, carbamazepine, dihydralazine, furafylline, isoniazid, rofecoxib, clorgyline, thiabendazole, and zileuton are mechanism-based inhibitors of CYP1A2. Reversible and

  7. 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. PMID:24535947

  8. Interaction of natural products with cell survival and signaling pathways in the biochemical elucidation of drug targets in cancer.

    PubMed

    Qurishi, Yasrib; Hamid, Abid; Majeed, Rabiya; Hussain, Aashiq; Qazi, Asif K; Ahmed, Mudassier; Zargar, Mohmmad Afzal; Singh, Shashank Kumar; Saxena, Ajit Kumar

    2011-08-01

    The use of natural products with therapeutic properties is as ancient as human civilization and for a long time mineral, plant and animal products were the main sources of drugs. Worldwide sales of medicinal plants, crude extracts and finished products amounted to US$15 billion in 1999 and it increased to $23 billion in 2002. More interestingly, the influence of natural products upon anticancer drug discovery and design cannot be underestimated. Approximately 60% of all drugs in clinical trials are either a natural product, compounds derived from natural products or contain pharmacophores derived from active natural products. Thus, even today, in the presence of massive numbers of agents from combinatorial libraries, compounds from natural sources are still in the forefront of cancer chemotherapeutics as sources of active drug types, as well as being involved in drug discovery in diseases such as microbial and parasitic infections and the control of cholesterol/lipids, among other functions. PMID:21823895

  9. What's Love Got to Do with It? Rethinking Common Sense Assumptions

    ERIC Educational Resources Information Center

    Trachman, Matthew; Bluestone, Cheryl

    2005-01-01

    One of the most basic tasks in introductory social science classes is to get students to reexamine their common sense assumptions concerning human behavior. This article introduces a shared assignment developed for a learning community that paired an introductory sociology and psychology class. The assignment challenges students to rethink the…

  10. 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…

  11. 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,…

  12. 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…

  13. 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…

  14. 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…

  15. 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…

  16. Sexual Outlaws and Class Struggle: Rethinking History and Class-Consciousness from a Queer Perspective

    ERIC Educational Resources Information Center

    Libretti, Tim

    2004-01-01

    The rethinking history and a queer perspective of the consciousness regarding the sexual outlaws and class struggle is explained. On a theoretical level, the homophobia results in an impoverished and undialectical understanding of class and class consciousness as it precludes the comprehension that classes are composed of people of different…

  17. 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…

  18. 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…

  19. 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…

  20. 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…

  1. 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…

  2. 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,…

  3. 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…

  4. 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…

  5. 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 from-the-classroom…

  6. Beyond Inquiry-Oriented Teacher Education: Rethinking the Practicum. Monograph No. 17.

    ERIC Educational Resources Information Center

    Zeichner, Kenneth M.

    This paper highlights some emerging trends in rethinking the teacher education practicum in North America. The paper discusses several major obstacles to student teacher learning that persist even in many of the new inquiry-oriented practicums that focus on the development of reflective teaching practice. While teachers praise the value of the…

  7. 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…

  8. The RETHINK Parenting and Anger Management Program: A Follow-Up Validation Study

    ERIC Educational Resources Information Center

    Fetsch, Robert J.; Yang, Raymond K.; Pettit, Matthew J.

    2008-01-01

    This study is the first follow-up assessment of the RETHINK Parenting and Anger Management Program. Parent participants (N = 168) reduced their anger, violence, and family conflict levels from posttest to follow-up, on average, at 2.5 months on 13 of 15 dependent variables. Current findings are consistent with a small, albeit growing body of…

  9. 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…

  10. 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 prominence of…

  11. The Second Educational Revolution: Rethinking Education in the Age of Technology

    ERIC Educational Resources Information Center

    Collins, A.; Halverson, R.

    2010-01-01

    This paper drew upon a recent book ("Rethinking Education in the Age of Technology") to summarize a number of prospects and challenges arising from the appropriation of digital technology into learning and educational practice. Tensions between traditional models of schooling and the affordances of digital media were noted, while the promise of…

  12. 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.

  13. High-Affinity Small-Molecule Inhibitors of the Menin-Mixed Lineage Leukemia (MLL) Interaction Closely Mimic a Natural Protein–Protein Interaction

    PubMed Central

    2015-01-01

    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. PMID:24472025

  14. Proteomic characterization of a natural host-pathogen interaction: repertoire of in vivo expressed bacterial and host surface-associated proteins.

    PubMed

    Rees, Megan A; Kleifeld, Oded; Crellin, Paul K; Ho, Bosco; Stinear, Timothy P; Smith, A Ian; Coppel, Ross L

    2015-01-01

    Interactions between a host and a bacterial pathogen are mediated by cross-talk between molecules present on, or secreted by, pathogens and host binding-molecules. Identifying proteins involved at this interface would provide substantial insights into this interaction. Although numerous studies have examined in vitro models of infection at the level of transcriptional change and proteomic profiling, there is virtually no information available on naturally occurring host-pathogen interactions in vivo. We employed membrane shaving to identify peptide fragments cleaved from surface-expressed bacterial proteins and also detected proteins originating from the infected host. We optimized this technique for media-cultured Corynebacterium pseudotuberculosis, a sheep pathogen, revealing a set of 247 surface proteins. We then studied a natural host-pathogen interaction by performing membrane shaving on C. pseudotuberculosis harvested directly from naturally infected sheep lymph nodes. Thirty-one bacterial surface proteins were identified, including 13 not identified in culture media, suggesting that a different surface protein repertoire is expressed in this hostile environment. Forty-nine host proteins were identified, including immune mediators and antimicrobial peptides such as cathelicidin. This novel application of proteolytic shaving has documented sets of host and pathogen proteins present at the bacterial surface in an infection of the native host. PMID:25329524

  15. Interactions of ciprofloxacin (CIP), titanium dioxide (TiO2) nanoparticles and natural organic matter (NOM) in aqueous suspensions.

    PubMed

    Fries, Elke; Crouzet, Catherine; Michel, Caroline; Togola, Anne

    2016-09-01

    The aim of the present study was to investigate interactions of the antibiotic ciprofloxacin (CIP), titanium dioxide nanoparticles (TiO2 NP) and natural organic matter (NOM) in aqueous suspensions. The mean hydrodynamic diameter of particles of TiO2 NP and NOM in the suspensions ranged from 113 to 255nm. During batch experiments the radioactivity resulting from (14)CIP was determined in the filtrate (filter pore size 100nm) by scintillation measurements. Up to 72h, no significant sorption of NOM to TiO2 NP was observed at a TiO2 NP concentration of 5mg/L. When the concentration of TiO2 NP was increased to 500mg/L, a small amount of NOM of 9.5%±0.6% was sorbed at 72h. The low sorption affinity of NOM on TiO2 NP surfaces could be explained by the negative charge of both components in alkaline media or by the low hydrophobicity of the NOM contents. At a TiO2 NP concentration of 5mgL(-1), the sorption of CIP on TiO2 NP was insignificant (TiO2 NP/CIP ratio: 10). When the TiO2 NP/CIP ratio was increased to 1000, a significant amount of 53.6%±7.2% of CIP was sorbed on TiO2 NP under equilibrium conditions at 64h. In alkaline media, CIP is present mainly as zwitterions which have an affinity to sorb on negatively charged TiO2 NP surfaces. The sorption of CIP on TiO2 NP in the range of TiO2 NP concentrations currently estimated for municipal wastewater treatment plants is estimated to be rather low. The Freundlich sorption coefficients (KF) in the presence of NOM of 2167L(n)mgmg(-n)kg(-1) was about 10 times lower than in the absence of NOM. This is an indication that the particle fraction of NOM<100nm could play a role as a carrier for ionic organic micro-pollutants as CIP. PMID:26765511

  16. 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. PMID:27282025

  17. 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

  18. INTERACTIONS OF NATURAL ORGANIC MATTER WITH C60 FULLERENE AND THEIR IMPACT ON C60 TRANSPORT, BIOAVAILABILITY AND TOXICITY

    EPA Science Inventory

    The outcome of the project is expected to provide 1) a realistic estimate of C60 exposure levels in natural aqueous environment; 2) quantitative description of nC60 transport behavior in systems well representing the natural aqueous environment; 3) id...

  19. 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.

  20. 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. PMID:21115520

  1. Rethinking the politics and implementation of health in all policies

    PubMed Central

    2013-01-01

    In Europe, successful health policies have contributed to a continued decline in mortality. However, not all parts of Europe have benefited equally and the sustainability of achievements cannot be taken for granted since health policies vary widely even among neighbouring countries. Furthermore, there are a number of remaining public health challenges such as food and alcohol polices. We argue that if we are to make further progress we need to rethink the politics and implementation of Health in All Policies. Commenting on an article analyzing the roll out and early implementation of Israel’s National Programme to Promote Active, Healthy Lifestyles provides an opportunity to thrash out four issues. First, intersectoral structures are key transmission belts for Health in All Policies between ministries and sectors and we need to exploit their specific uses and understand their limitations. Second, our analytical perspective should focus on what it takes to introduce policy change instead of assuming an idealized policy cycle. This includes a reconsideration of interventions which may not be very effective but help to raise the standing of health on the political agenda, thus providing a stronger basis for policy change. Third, we need to better understand variations in context between and within countries, e.g. why do some countries adopt Health in All policies but others don’t, and why is it that in the same country compliance with some health policies is better than with others. Finally, we will need to better understand how a diverse set of actors from other sectors can internalize health as an intrinsic value. PMID:23607717

  2. 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.

  3. 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

    2016-01-01

    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. PMID:26572767

  4. Environmental and genetic interactions reveal FLOWERING LOCUS C as a modulator of the natural variation for the plasticity of flowering in Arabidopsis.

    PubMed

    Méndez-Vigo, Belén; Savic, Marija; Ausín, Israel; Ramiro, Mercedes; Martín, Beatriz; Picó, F Xavier; Alonso-Blanco, Carlos

    2016-02-01

    The timing of flowering initiation depends strongly on the environment, a property termed as the plasticity of flowering. Such plasticity determines the adaptive potential of plants because it provides phenotypic buffer against environmental changes, and its natural variation contributes to evolutionary adaptation. We addressed the genetic mechanisms of the natural variation for this plasticity in Arabidopsis thaliana by analysing a population of recombinant inbred lines derived from Don-0 and Ler accessions collected from distinct climates. Quantitative trait locus (QTL) mapping in four environmental conditions differing in photoperiod, vernalization treatment and ambient temperature detected the folllowing: (i) FLOWERING LOCUS C (FLC) as a large effect QTL affecting flowering time differentially in all environments; (ii) numerous QTL displaying smaller effects specifically in some conditions; and (iii) significant genetic interactions between FLC and other loci. Hence, the variation for the plasticity of flowering is determined by a combination of environmentally sensitive and specific QTL, and epistasis. Analysis of FLC from Don identified a new and more active allele likely caused by a cis-regulatory deletion covering the non-coding RNA COLDAIR. Further characterization of four FLC natural alleles showed different environmental and genetic interactions. Thus, FLC appears as a major modulator of the natural variation for the plasticity of flowering to multiple environmental factors. PMID:26173848

  5. 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. PMID:23635109

  6. How Not to Become a Buffoon in Front of a Shop Window: A Solution Allowing Natural Head Movement for Interaction with a Public Display

    NASA Astrophysics Data System (ADS)

    Mubin, Omar; Lashina, Tatiana; van Loenen, Evert

    The user interaction solution described in this paper was developed in the context of an Intelligent Shop Window (ISW) with an aim to offer a user the interaction solution where system response would be triggered by naturally gazing at products. We have analyzed a possibility to realize such a user interaction solution using gaze tracking and concluded that remote calibration free eye tracking is still a subject of academic research, but that head tracking could be used instead. We argue that conventional use of head tracking requires conscious intentional head movements and thus does not fit into the context of applications such as the ISW. We further describe our experiment aimed to explore how head movements relate to eye movements when looking at objects in a shop window context. We show large variability in head movement and that per individual the gaze-head data could well be approximated with a straight line. Based on these results we propose a new solution that enables natural gaze interaction by means of head tracking.

  7. Natural and augmented snowfall growth processes and their interactions with the natural and modified aerosol. Final report, 1 March 1989-30 AprIL 1990

    SciTech Connect

    Warburton, J.

    1991-07-01

    The second annual report describes the activities performed under seven separate tasks. These are the same tasks as outlined in the original proposal for the three-year program of research. These tasks dealt with the development of a trace chemical method of assessing the effects of seeding in a snow producing environment and the use of the stable isotopes of water for assessing the regions of ice-phase water capture in the cloud systems from which precipitation fell in the study regions. They also dealt with the theoretical aspects of these trace chemical programs of study and with the roles which trace impurities can play in affecting the growth characteristics of ice particles in supercooled clouds and of the shapes and number fluxes of ice crystals which occur under both natural and artificially seeded conditions. These tasks also included studies of the supercooled liquid water and ice contents of winter storms over the central Sierra Nevada, both spatially and temporally through the use of ground-based remote sensing radar and microwave radiometers. Some work was also conducted on the further development of new aircraft instrumentation for measuring atmospheric motions and the microphysical composition of winter orographic clouds.

  8. 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. PMID:25477521

  9. 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

  10. Enhancement effect of water associated with natural organic matter (NOM) on organic compound-NOM interactions: a case study with carbamazepine.

    PubMed

    Borisover, Mikhail; Sela, Maggie; Chefetz, Benny

    2011-03-01

    Natural organic matter (NOM) in soils and sediments is recognized to strongly affect environmental distributions of organic compounds. Water associated with NOM may have a significant impact on NOM-organic compound interactions. The objectives of this research were (1) to determine the effect of hydration of a model NOM sorbent on interactions with a probe organic compound, carbamazepine (CBZ), and (2) based on the comparison with the literature data, to evaluate the effect of organic compound structure on the cooperative participation of water molecules in organic sorbate-NOM interactions. CBZ is one of the most widely reported water pollutants from the pharmaceutical and personal care products family. Therefore, CBZ sorption on Pahokee peat was compared from water and from n-hexadecane, using solubility-normalized solute concentrations. CBZ-NOM interactions were enhanced by one to two orders of magnitudes when NOM became fully hydrated. This enhancement is associated with the distinct ability of CBZ to undergo strong, specific interactions with NOM which was revealed by comparing the transfer of CBZ and another model sorbate, phenanthrene, from solution in n-hexadecane to the hydrated NOM sorbent. The enhancing effect of NOM hydration on CBZ-NOM interactions was also observed when CBZ sorption was examined on partially hydrated NOM. In comparison with a smaller-size organic sorbate such as phenol, CBZ needs more NOM-associated water in order to demonstrate the strengthening of interactions with NOM. Therefore, for penetration of the larger sorbate molecules into the NOM interior, a greater number of water molecules are needed to compensate for the local NOM disintegration thus suggesting the greater extent of the cooperativity in an involvement of water molecules in the CBZ-NOM interactions. PMID:21138776

  11. 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…

  12. Enhancing Learner-Learner Interaction Using Video Communications in Higher Education: Implications from Theorising about a New Model

    ERIC Educational Resources Information Center

    Smyth, Robyn

    2011-01-01

    As visual connectivity improves, an opportunity to enrich and rethink the place of learning design in online and distance education is presenting itself. The opportunity is derived from the increasing scope for personalised synchronous interaction which has been missing in computer mediated communications (CMC) and previous generations of distance…

  13. Interaction between Pin1 and its natural product inhibitor epigallocatechin-3-gallate by spectroscopy and molecular dynamics simulations.

    PubMed

    Xi, Lei; Wang, Yu; He, Qing; Zhang, Qingyan; Du, Linfang

    2016-12-01

    The binding of epigallocatechin-3-gallate (EGCG) to wild type Pin1 in solution was studied by spectroscopic methods and molecular dynamics simulations in this research to explore the binding mode and inhibition mechanism. The binding constants and number of binding sites per Pin1 for EGCG were calculated through the Stern-Volmer equation. The values of binding free energy and thermodynamic parameters were calculated and indicated that hydrogen bonds, electrostatic interaction and Van der Waals interaction played the major role in the binding process. The alterations of Pin1 secondary structure in the presence of EGCG were confirmed by far-UV circular dichroism spectra. The binding model at atomic-level revealed that EGCG was bound to the Glu12, Lys13, Arg14, Met15 and Arg17 in WW domain. Furthermore, EGCG could also interact with Arg69, Asp112, Cys113 and Ser114 in PPIase domain. PMID:27372509

  14. Physical nature of intermolecular interactions inside Sir2 homolog active site: molecular dynamics and ab initio study.

    PubMed

    Czeleń, Przemysław; Czyżnikowska, Żaneta

    2016-06-01

    In the present study, we analyze the interactions of NAD+-dependent deacetylase (Sir2 homolog yeast Hst2) with carba-nicotinamide-adenine-dinucleotide (ADP-HPD). For the Sir2 homolog, a yeast Hst2 docking procedure was applied. The structure of the protein-ADP-HPD complex obtained during the docking procedure was used as a starting point for molecular dynamics simulation. The intermolecular interaction energy partitioning was performed for protein-ADP-HPD complex resulting from molecular dynamics simulation. The analysis was performed for ADP-HPD and 15 amino acids forming a deacetylase binding pocket. Although the results indicate that the first-order electrostatic interaction energy is substantial, the presence of multiple hydrogen bonds in investigated complexes can lead to significant value of induction component. PMID:27154340

  15. 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. PMID:27302488

  16. 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. PMID:24703184

  17. 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. PMID:22967349

  18. 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…

  19. 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...

  20. 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

    2016-01-01

    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. PMID:27530534

  1. 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,…

  2. Characterizing natural hydrogel for reconstruction of three-dimensional lymphoid stromal network to model T-cell interactions.

    PubMed

    Kim, Jiwon; Wu, Biming; Niedzielski, Steven M; Hill, Matthew T; Coleman, Rhima M; Ono, Akira; Shikanov, Ariella

    2015-08-01

    Hydrogels have been used in regenerative medicine because they provide a three-dimensional environment similar to soft tissues, allow diffusion of nutrients, present critical biological signals, and degrade via endogenous enzymatic mechanisms. Herein, we developed in vitro system mimicking cell-cell and cell-matrix interactions in secondary lymphoid organs (SLOs). Existing in vitro culture systems cannot accurately represent the complex interactions happening between T-cells and stromal cells in immune response. To model T-cell interaction in SLOs in vitro, we encapsulated stromal cells in fibrin, collagen, or fibrin-collagen hydrogels and studied how different mechanical and biological properties affect stromal network formation. Overall, fibrin supplemented with aprotinin was superior to collagen and fibrin-collagen in terms of network formation and promotion of T-cell penetration. After 8 days of culture, stromal networks formed through branching and joining with other adjacent cell populations. T-cells added to the newly formed stromal networks migrated and attached to stromal cells, similar to the T-cell zones of the lymph nodes in vivo. Our results suggest that the constructed three-dimensional lymphoid stromal network can mimic the in vivo environment and allow the modeling of T-cell interaction in SLOs. PMID:25649205

  3. The Nature of Interactions between Chinese Immigrant Families and Preschool Staff: How Culture, Class, and Methodology Matter

    ERIC Educational Resources Information Center

    Heng, Tang T.

    2014-01-01

    While the parental involvement field has progressed from asking what the impact of parental involvement is to how we can better involve parents, research has lagged in finding out how sociocultural and class differentials between homes and schools affect immigrant families' interactions with schools. This case study uses ethnographic tools to…

  4. 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.

  5. Drug interaction study of natural steroids from herbs specifically toward human UDP-glucuronosyltransferase (UGT) 1A4 and their quantitative structure activity relationship (QSAR) analysis for prediction.

    PubMed

    Xu, Min; Dong, Peipei; Tian, Xiangge; Wang, Chao; Huo, Xiaokui; Zhang, Baojing; Wu, Lijun; Deng, Sa; Ma, Xiaochi

    2016-08-01

    The wide application of herbal medicines and foods containing steroids has resulted in the high risk of herb-drug interactions (HDIs). The present study aims to evaluate the inhibition potential of 43 natural steroids from herb medicines toward human UDP- glucuronosyltransferases (UGTs). A remarkable structure-dependent inhibition toward UGT1A4 was observed in vitro. Some natural steroids such as gitogenin, tigogenin, and solasodine were found to be the novel selective inhibitors of UGT1A4, and did not inhibit the activities of major human CYP isoforms. To clarify the possibility of the in vivo interaction of common steroids and clinical drugs, the kinetic inhibition type and related kinetic parameters (Ki) were measured. The target compounds 2-6 and 15, competitively inhibited the UGT1A4-catalyzed trifluoperazine glucuronidation reaction, with Ki values of 0.6, 0.18, 1.1, 0.7, 0.8, and 12.3μM, respectively. And this inhibition of steroids towards UGT1A4 was also verified in human primary hepatocytes. Furthermore, a quantitative structure-activity relationship (QSAR) of steroids with inhibitory effects toward human UGT1A4 isoform was established using the computational methods. Our findings elucidate the potential for in vivo HDI effects of steroids in herbal medicine and foods, with the clinical dr ugs eliminated by UGT1A4, and reveal the vital pharamcophoric requirement of natural steroids for UGT1A4 inhibition activity. PMID:27208893

  6. Rethinking the role and impact of health information technology: informatics as an interventional discipline.

    PubMed

    Payne, Philip R O; Lussier, Yves; Foraker, Randi E; Embi, Peter J

    2016-01-01

    Recent advances in the adoption and use of health information technology (HIT) have had a dramatic impact on the practice of medicine. In many environments, this has led to the ability to achieve new efficiencies and levels of safety. In others, the impact has been less positive, and is associated with both: 1) workflow and user experience dissatisfaction; and 2) perceptions of missed opportunities relative to the use of computational tools to enable data-driven and precise clinical decision making. Simultaneously, the "pipeline" through which new diagnostic tools and therapeutic agents are being developed and brought to the point-of-care or population health is challenged in terms of both cost and timeliness. Given the confluence of these trends, it can be argued that now is the time to consider new ways in which HIT can be used to deliver health and wellness interventions comparable to traditional approaches (e.g., drugs, devices, diagnostics, and behavioral modifications). Doing so could serve to fulfill the promise of what has been recently promoted as "precision medicine" in a rapid and cost-effective manner. However, it will also require the health and life sciences community to embrace new modes of using HIT, wherein the use of technology becomes a primary intervention as opposed to enabler of more conventional approaches, a model that we refer to in this commentary as "interventional informatics". Such a paradigm requires attention to critical issues, including: 1) the nature of the relationships between HIT vendors and healthcare innovators; 2) the formation and function of multidisciplinary teams consisting of technologists, informaticians, and clinical or scientific subject matter experts; and 3) the optimal design and execution of clinical studies that focus on HIT as the intervention of interest. Ultimately, the goal of an "interventional informatics" approach can and should be to substantially improve human health and wellness through the use of data

  7. Rethinking Emancipation, Rethinking Education

    ERIC Educational Resources Information Center

    Safstrom, Carl Anders

    2011-01-01

    In this paper I discuss the possibility of the idea of emancipation within an educational philosophy that does not accept schooling as its first premise. The first part of the paper will take Sweden as an example of an educational state defined through educational policies such as life long learning, accountability and evidence-based research, and…

  8. Trends in Thermostability Provide Information on the Nature of Substrate, Inhibitor, and Lipid Interactions with Mitochondrial Carriers*

    PubMed Central

    Crichton, Paul G.; Lee, Yang; Ruprecht, Jonathan J.; Cerson, Elizabeth; Thangaratnarajah, Chancievan; King, Martin S.; Kunji, Edmund R. S.

    2015-01-01

    Mitochondrial carriers, including uncoupling proteins, are unstable in detergents, which hampers structural and mechanistic studies. To investigate carrier stability, we have purified ligand-free carriers and assessed their stability with a fluorescence-based thermostability assay that monitors protein unfolding with a thiol-reactive dye. We find that mitochondrial carriers from both mesophilic and thermophilic organisms exhibit poor stability in mild detergents, indicating that instability is inherent to the protein family. Trends in the thermostability of yeast ADP/ATP carrier AAC2 and ovine uncoupling protein UCP1 allow optimal conditions for stability in detergents to be established but also provide mechanistic insights into the interactions of lipids, substrates, and inhibitors with these proteins. Both proteins exhibit similar stability profiles across various detergents, where stability increases with the size of the associated detergent micelle. Detailed analysis shows that lipids stabilize carriers indirectly by increasing the associated detergent micelle size, but cardiolipin stabilizes by direct interactions as well. Cardiolipin reverses destabilizing effects of ADP and bongkrekic acid on AAC2 and enhances large stabilizing effects of carboxyatractyloside, revealing that this lipid interacts in the m-state and possibly other states of the transport cycle, despite being in a dynamic interface. Fatty acid activators destabilize UCP1 in a similar way, which can also be prevented by cardiolipin, indicating that they interact like transport substrates. Our controls show that carriers can be soluble but unfolded in some commonly used detergents, such as the zwitterionic Fos-choline-12, which emphasizes the need for simple validation assays like the one used here. PMID:25653283

  9. 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. PMID:25935119

  10. The Effect of Plant Inbreeding and Stoichiometry on Interactions with Herbivores in Nature: Echinacea angustifolia and Its Specialist Aphid

    PubMed Central

    Wagenius, Stuart; Stanton-Geddes, John; Shaw, Ruth G.

    2011-01-01

    Fragmentation of once widespread communities may alter interspecific interactions by changing genetic composition of interacting populations as well as their abundances and spatial distributions. In a long-term study of a fragmented population of Echinacea angustifolia, a perennial plant native to the North American prairie, we investigated influences on its interaction with a specialist aphid and tending ants. We grew plant progeny of sib-matings (I), and of random pairings within (W) and between (B) seven remnants in a common field within 8 km of the source remnants. During the fifth growing season, we determined each plant's burden of aphids and ants, as well as its size and foliar elemental composition (C, N, P). We also assayed composition (C, N) of aphids and ants. Early in the season, progeny from genotypic classes B and I were twice as likely to harbor aphids, and in greater abundance, than genotypic class W; aphid loads were inversely related to foliar concentration of P and positively related to leaf N and plant size. At the end of the season, aphid loads were indistinguishable among genotypic classes. Ant abundance tracked aphid abundance throughout the season but showed no direct relationship with plant traits. Through its potential to alter the genotypic composition of remnant populations of Echinacea, fragmentation can increase Echinacea's susceptibility to herbivory by its specialist aphid and, in turn, perturb the abundance and distribution of aphids. PMID:21935460

  11. 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. PMID:26740568

  12. tRNA binding with anti-cancer alkaloids-nature of interaction and comparison with DNA-alkaloids adducts.

    PubMed

    Tyagi, Gunjan; Agarwal, Shweta; Mehrotra, Ranjana

    2015-01-01

    Vincristine and vinblastine are potent anti-proliferative compound whose mechanism of action inside a cell is not well elucidated and the basis of their differential cellular effect is also unknown. This work focuses towards understanding the interaction of vincristine and vinblastine with tRNA using spectroscopic approach. Fourier transform infrared (FTIR) spectroscopy, Fourier transform infrared difference spectroscopy and UV-visible spectroscopy were used to study the binding parameters of tRNA-alkaloids interaction. Both the vinca alkaloids interact with tRNA through external binding with some degree of intercalation into the nitrogenous bases. The alkaloids adduct formation did not alter the A-conformation of the biopolymer and vincristine-tRNA complexes were found to be more stable than that of vinblastine-tRNA complexes. The binding constants (K) estimated for VCR-tRNA and VBS-tRNA complexation are 3×10(2)M(-1) and 2.5×10(2)M(-1) respectively, which suggests low affinity of alkaloids to tRNA. The study recognizes tRNA binding properties of vital vinca alkaloids and contributes to a better understanding of their mechanism of action and could also help in identifying the reason behind their diverse action in a cell. PMID:25574589

  13. 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

  14. 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.

  15. 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

  16. 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. PMID:22437404

  17. Natural variant of the Helicobacter pylori CagA oncoprotein that lost the ability to interact with PAR1.

    PubMed

    Hashi, Kana; Murata-Kamiya, Naoko; Varon, Christine; Mégraud, Francis; Dominguez-Bello, Maria Gloria; Hatakeyama, Masanori

    2014-03-01

    Helicobacter pylori strains carrying the cagA gene are associated with severe disease outcomes, most notably gastric cancer. CagA protein is delivered into gastric epithelial cells by a type IV secretion system. The translocated CagA undergoes tyrosine phosphorylation at the C-terminal EPIYA motifs by host cell kinases. Tyrosine-phosphorylated CagA acquires the ability to interact with and activate SHP2, thereby activating mitogenic signaling and inducing cell morphological transformation (hummingbird phenotype). CagA also interacts with PAR1b via the CM sequence, resulting in induction of junctional and polarity defects. Furthermore, CagA-PAR1b interaction stabilizes the CagA-SHP2 complex. Because transgenic mice systemically expressing CagA develop gastrointestinal and hematological malignancies, CagA is recognized as a bacterium-derived oncoprotein. Interestingly, the C-terminal region of CagA displays a large diversity among H. pylori strains, which influences the ability of CagA to bind to SHP2 and PAR1b. In the present study, we investigated the biological activity of v225d CagA, an Amerindian CagA of H. pylori isolated from a Venezuelan Piaroa Amerindian subject, because the variant CagA does not possess a canonical CM sequence. We found that v225d CagA interacts with SHP2 but not PAR1b. Furthermore, SHP2-binding activity of v225d CagA was much lower than that of CagA of H. pylori isolated from Western countries (Western CagA). v225d CagA also displayed a reduced ability to induce the hummingbird phenotype than that of Western CagA. Given that perturbation of PAR1b and SHP2 by CagA underlies the oncogenic potential of CagA, the v225d strain is considered to be less oncogenic than other well-studied cagA-positive H. pylori strains. PMID:24354359

  18. Rethinking quasispecies theory: From fittest type to cooperative consortia

    PubMed Central

    Villarreal, Luis P; Witzany, Guenther

    2013-01-01

    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. PMID:24340131

  19. 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.

  20. Broadening Perspectives on Clinical Performance Assessment: Rethinking the Nature of In-Training Assessment

    ERIC Educational Resources Information Center

    Govaerts, Marjan J. B.; van der Vleuten, Cees P. M.; Schuwirth, Lambert W. T.; Muijtjens, Arno M. M.

    2007-01-01

    Context: In-training assessment (ITA), defined as multiple assessments of performance in the setting of day-to-day practice, is an invaluable tool in assessment programmes which aim to assess professional competence in a comprehensive and valid way. Research on clinical performance ratings, however, consistently shows weaknesses concerning…

  1. Rethinking Coal: Thin Films of Solution Processed Natural Carbon Nanoparticles for Electronic Devices.

    PubMed

    Keller, Brent D; Ferralis, Nicola; Grossman, Jeffrey C

    2016-05-11

    Disordered carbon materials, both amorphous and with long-range order, have been used in a variety of applications, from conductive additives and contact materials to transistors and photovoltaics. Here we show a flexible solution-based method of preparing thin films with tunable electrical properties from suspensions of ball-milled coals following centrifugation. The as-prepared films retain the rich carbon chemistry of the starting coals with conductivities ranging over orders of magnitude, and thermal treatment of the resulting films further tunes the electrical conductivity in excess of 7 orders of magnitude. Optical absorption measurements demonstrate tunable optical gaps from 0 to 1.8 eV. Through low-temperature conductivity measurements and Raman spectroscopy, we demonstrate that variable range hopping controls the electrical properties in as-prepared and thermally treated films and that annealing increases the sp(2) content, localization length, and disorder. The measured hopping energies demonstrate electronic properties similar to amorphous carbon materials and reduced graphene oxide. Finally, Joule heating devices were fabricated from coal-based films, and temperatures as high as 285 °C with excellent stability were achieved. PMID:27031328

  2. Auditory Warnings, Signal-Referent Relations, and Natural Indicators: Re-Thinking Theory and Application

    ERIC Educational Resources Information Center

    Petocz, Agnes; Keller, Peter E.; Stevens, Catherine J.

    2008-01-01

    In auditory warning design the idea of the strength of the association between sound and referent has been pivotal. Research has proceeded via constructing classification systems of signal-referent associations and then testing predictions about ease of learning of different levels of signal-referent relation strength across and within different…

  3. Quantitative EPR study on free radicals in the natural polyphenols interacting with metal ions and other environmental pollutants

    NASA Astrophysics Data System (ADS)

    Jezierski, Adam; Czechowski, Franciszek; Jerzykiewicz, Maria; Golonka, Iwona; Drozd, Jerzy; Bylinska, Ewa; Chen, Yona; Seaward, Mark R. D.

    2002-04-01

    Quantitative electron paramagnetic resonance (EPR) method was applied to characterise radicals stabilised in polyphenolic matrices of various biogenic materials: lichens, mosses, composts, soils, peats, brown coals and sewage sludge sediments. The investigations were carried out on raw materials and extracted fractions of humic acids (HA). General trends of g value and spin concentration changes were found. These parameters in lichens strongly depend on lichen species and air pollution. Determination of the g value and semiquinone spin concentration allows to assess degree of transformation of organic matter in compost, soil, peat and lignite. Application of gaseous ammonia as a base penetrating the organic matrices extends the possibilities and usefulness of the method. Interaction of metal ions with humic materials is illustrated by interaction of VO 2+ ion with peat and lignite HA as well as demineralised (raw and carbonised) brown coal. Our investigations demonstrate that quantitative EPR is a rapid and effective monitoring method to study the influence of various environmental factors on substances containing polyphenolic matrices.

  4. 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.

  5. Surface chemical characteristics of coal fly ash particles after interaction with seawater under natural deep sea conditions

    SciTech Connect

    Brami, Y.; Shemesh, A.; Cohen, H.; Herut, B.

    1999-01-15

    The surface chemical characteristics of coal fly ash (CFA) before and after interaction with Mediterranean deep seawater was studied by X-ray photoelectron spectroscopy (XPS). Significantly lower values of Si, Ca, and S and higher values of Mg and Cl were found in the retrieved CFA as compared to fresh CFA. It is suggested that hydrolysis of the oxide matrixes results in an alkaline environment which rapidly leads to several chemical reactions. The two most important are (a) dissolution of the amorphous silicate and the calcium phases and (b) precipitation of Mg(OH){sub 2}-brucite. A depth profile of the retrieved CFA was measured by both line-shape analysis of the XPS spectra and by consecutive cycle of sputtering. The thickness of the brucite layer is estimated to be 1.3 nm.

  6. 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

  7. 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. PMID:26905418

  8. 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

  9. Interaction of Bovine Peripheral Blood Polymorphonuclear Cells and Leptospira Species; Innate Responses in the Natural Bovine Reservoir Host.

    PubMed

    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

  10. Probing the Kinetic Parameters of Plutonium-Naturally Occurring Organic Matter Interactions in Freshwaters Using the Diffusive Gradients in Thin Films Technique.

    PubMed

    Cusnir, Ruslan; Jaccard, Maud; Bailat, Claude; Christl, Marcus; Steinmann, Philipp; Haldimann, Max; Bochud, François; Froidevaux, Pascal

    2016-05-17

    The interaction of trace metals with naturally occurring organic matter (NOM) is a key process of the speciation of trace elements in aquatic environments. The rate of dissociation of metal-NOM complexes will impact the amount of free metal available for biouptake. Assessing the bioavailability of plutonium (Pu) helps to predict its toxic effects on aquatic biota. However, the rate of dissociation of Pu-NOM complexes in natural freshwaters is currently unknown. Here, we used the technique of diffusive gradients in thin films (DGT) with several diffusive layer thicknesses to provide new insights into the dissociation kinetics of Pu-NOM complexes. Results show that Pu complexes with NOM (mainly fulvic acid) are somewhat labile (0.2 ≤ ξ ≤ 0.4), with kd = 7.5 × 10(-3) s(-1). DGT measurements of environmental Pu in organic-rich natural water confirm these findings. In addition, we determined the effective diffusion coefficients of Pu(V) in polyacrylamide (PAM) gel in the presence of humic acid using a diffusion cell (D = 1.70 ± 0.25 × 10(-6) cm(2) s(-1)). These results show that Pu(V) is a more mobile species than Pu(IV). PMID:27064997

  11. 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. PMID:26868103

  12. 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. PMID:27039144

  13. Mortality trajectory analysis reveals the drivers of sex-specific epidemiology in natural wildlife–disease interactions

    PubMed Central

    McDonald, Jennifer L.; Smith, Graham C.; McDonald, Robbie A.; Delahay, Richard J.; Hodgson, Dave

    2014-01-01

    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. PMID:25056621

  14. 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.

  15. Interaction with Mesenchymal Stem Cells Provokes Natural Killer Cells for Enhanced IL-12/IL-18-Induced Interferon-Gamma Secretion

    PubMed Central

    Thomas, Heike; Jäger, Marcus; Mauel, Katharina; Brandau, Sven; Lask, Sara; Flohé, Stefanie B.

    2014-01-01

    Tissue injury induces an inflammatory response accompanied by the recruitment of immune cells and of mesenchymal stem cells (MSC) that contribute to tissue regeneration. After stimulation with interleukin- (IL-) 12 and IL-18 natural killer (NK) cells secrete the proinflammatory cytokine interferon- (IFN-) γ. IFN-γ plays a crucial role in the defense against infections and modulates tissue regeneration. In consideration of close proximity of NK cells and MSC at the site of injury we investigated if MSC could influence the ability of NK-cells to produce IFN-γ. Coculture experiments were performed with bone marrow-derived human MSC and human NK cells. MSC enhanced the ability of IL-12/IL-18-stimulated NK cells to secrete IFN-γ in a dose-dependent manner. This activation of NK cells was dependent on cell-cell contact as well as on soluble factors. The increased IFN-γ secretion from NK cells after contact with MSC correlated with an increased level of intracellular IFN-γ. Alterations in the IL-12 signaling pathway including an increased expression of the IL-12β1 receptor subunit and an increased phosphorylation of signal transducer and activator of transcription 4 (STAT4) could be observed. In conclusion, MSC enhance the IFN-γ release from NK cells which might improve the defense against infections at the site of injury but additionally might affect tissue regeneration. PMID:24876666

  16. Use of Spectroscopic Techniques to Reveal the Nature of the Interactions of Two Sialic Acid Specific Lectins with Gold Nanoparticles.

    PubMed

    Singha, Shuvendu; Dutta, Gopa; Bose, Partha P; Das, Subrata; Bardhan, Munmun; Chatterjee, Bishnu P; Ganguly, Tapan

    2016-01-01

    From UV-vis absorption, steady state and time resolved fluorescence measurements coupled with circular dichroism (CD) spectral studies, it was revealed that among the two lectins: Sambucus nigra agglutinin (SNA) and Saraca indica (saracin II), SNA forms stronger binding complex in the ground state with gold nanoparticles (GNPs). From the measurements of Stern-Volmer (SV) constants Ksv, and binding constants K(A) and number of binding sites two important inferences could be drawn. Firstly, the fluorescence quenching is primarily due to static quenching and secondly SNA forms stronger binding with GNPs relative to the other lectin saracin II. Synchronous fluorescence spectral measurements further substantiate this proposition of exhibiting the fully exposed tryptophan residue in case of SNA. It appears that the lectin SNA adopted a relatively looser conformation with the extended polypeptide structures leading to the exposure of the hydrophobic cavities which favoured stronger binding with GNPs. CD measurements demonstrate that gold nanoparticles when interact with the lectins (glycoproteins), no significant distortion in the structural pattern of the later occurs. The unaltered identity in the secondary structural pattern of both SNA and saracin II in presence of gold nanoparticles hints that GNPs may be used as useful drug or drug delivery systems. PMID:27398481

  17. 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.

  18. Physical Nature of Fatty Acid Amide Hydrolase Interactions with Its Inhibitors: Testing a Simple Nonempirical Scoring Model.

    PubMed

    Giedroyć-Piasecka, Wiktoria; Dyguda-Kazimierowicz, Edyta; Beker, Wiktor; Mor, Marco; Lodola, Alessio; Sokalski, W Andrzej

    2014-12-26

    Fatty acid amide hydrolase (FAAH) is an enzyme responsible for the deactivating hydrolysis of fatty acid ethanolamide neuromodulators. FAAH inhibitors have gained considerable interest due to their possible application in the treatment of anxiety, inflammation, and pain. In the context of inhibitor design, the availability of reliable computational tools for predicting binding affinity is still a challenging task, and it is now well understood that empirical scoring functions have several limitations that in principle could be overcome by quantum mechanics. Herein, systematic ab initio analyses of FAAH interactions with a series of inhibitors belonging to the class of the N-alkylcarbamic acid aryl esters have been performed. In contrast to our earlier studies of other classes of enzyme-inhibitor complexes, reasonable correlation with experimental results required us to consider correlation effects along with electrostatic term. Therefore, the simplest comprehensive nonempirical model allowing for qualitative predictions of binding affinities for FAAH ligands consists of electrostatic multipole and second-order dispersion terms. Such a model has been validated against the relative stabilities of the benchmark S66 set of biomolecular complexes. As it does not involve parameters fitted to experimentally derived data, this model offers a unique opportunity for generally applicable inhibitor design and virtual screening. PMID:25420234

  19. [Antagonistic interactions between stress factors during the growth of microorganisms under conditions simulating the parameters of their natural ecotopes].

    PubMed

    Arzumanian, V G; Voronina, N A; Geĭdebrekht, O V; Shelemekh, O V; Plakunov, V K; Beliaev, S S

    2002-01-01

    Two stress factors, hypoxia (microaerobic conditions) and a high salt concentration, if applied simultaneously to aerobic microorganisms, display an antagonistic mode of interaction. As a result, the NaCl level that is usually optimal for moderate halophiles (5-6%) becomes optimal for the growth of weak halophiles (Rhodococcus erythropolis and Shewanella sp. CN32); the halotolerant yeast Yarrowia lypolytica acquires halophilic properties (with a growth optimum at a NaCl concentration of 10%), and the growth rate of the extremely halophilic Halobacterium salinarum increases at supraoptimal salt concentrations (25-34%). This phenomenon is apparently due to multiple changes in metabolic reactions. In particular, high salt concentrations suppress respiration and the formation of enzymes (superoxide dismutase and catalase) that protect the cell from toxic oxygen species. Therefore, establishment of microaerobic conditions compensates for the loss of these protective mechanisms and enables cell growth at higher salt concentrations than under aerobic conditions. Of some importance can also be the increase in the intracellular concentrations of osmoprotectants caused by the suppression of their intracellular oxidation. The implications of this phenomenon for the ecophysiology of microorganisms (including oiloxidizing species) and for the classification of weak and moderate halophiles are discussed. PMID:12024812

  20. 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.

  1. Staphylococcal Phenotypes Induced by Naturally Occurring and Synthetic Membrane-Interactive Polyphenolic β-Lactam Resistance Modifiers

    PubMed Central

    Palacios, Lucia; Rosado, Helena; Micol, Vicente; Rosato, Adriana E.; Bernal, Patricia; Arroyo, Raquel; Grounds, Helen; Anderson, James C.; Stabler, Richard A.; Taylor, Peter W.

    2014-01-01

    Galloyl catechins, in particular (-)-epicatechin gallate (ECg), have the capacity to abrogate β-lactam resistance in methicillin-resistant strains of Staphylococcus aureus (MRSA); they also prevent biofilm formation, reduce the secretion of a large proportion of the exoproteome and induce profound changes to cell morphology. Current evidence suggests that these reversible phenotypic traits result from their intercalation into the bacterial cytoplasmic membrane. We have endeavoured to potentiate the capacity of ECg to modify the MRSA phenotype by stepwise removal of hydroxyl groups from the B-ring pharmacophore and the A:C fused ring system of the naturally occurring molecule. ECg binds rapidly to the membrane, inducing up-regulation of genes responsible for protection against cell wall stress and maintenance of membrane integrity and function. Studies with artificial membranes modelled on the lipid composition of the staphylococcal bilayer indicated that ECg adopts a position deep within the lipid palisade, eliciting major alterations in the thermotropic behaviour of the bilayer. The non-galloylated homolog (-)-epicatechin enhanced ECg-mediated effects by facilitating entry of ECg molecules into the membrane. ECg analogs with unnatural B-ring hydroxylation patterns induced higher levels of gene expression and more profound changes to MRSA membrane fluidity than ECg but adopted a more superficial location within the bilayer. ECg possessed a high affinity for the positively charged staphylococcal membrane and induced changes to the biophysical properties of the bilayer that are likely to account for its capacity to disperse the cell wall biosynthetic machinery responsible for β-lactam resistance. The ability to enhance these properties by chemical modification of ECg raises the possibility that more potent analogs could be developed for clinical evaluation. PMID:24699700

  2. 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

  3. 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.

  4. Interactions between Silicon Oxide Nanoparticles (SONPs) and U(VI) Contaminations: Effects of pH, Temperature and Natural Organic Matters.

    PubMed

    Wu, Hanyu; Li, Ping; Pan, Duoqiang; Yin, Zhuoxin; Fan, Qiaohui; Wu, Wangsuo

    2016-01-01

    The interactions between contaminations of U(VI) and silicon oxide nanoparticles (SONPs), both of which have been widely used in modern industry and induced serious environmental challenge due to their high mobility, bioavailability, and toxicity, were studied under different environmental conditions such as pH, temperature, and natural organic matters (NOMs) by using both batch and spectroscopic approaches. The results showed that the accumulation process, i.e., sorption, of U(VI) on SONPs was strongly dependent on pH and ionic strength, demonstrating that possible outer- and/or inner-sphere complexes were controlling the sorption process of U(VI) on SONPs in the observed pH range. Humic acid (HA), one dominated component of NOMs, bounded SONPs can enhance U(VI) sorption below pH~4.5, whereas restrain at high pH range. The reversible sorption of U(VI) on SONPs possibly indicated that the outer-sphere complexes were prevalent at pH 5. However, an irreversible interaction of U(VI) was observed in the presence of HA (Fig 1). It was mainly due to the ternary SONPs-HA-U(VI) complexes (Type A Complexes). After SONPs adsorbed U(VI), the particle size in suspension was apparently increased from ~240 nm to ~350 nm. These results showed that toxicity of both SONPs and U(VI) will decrease to some extent after the interaction in the environment. These findings are key for providing useful information on the possible mutual interactions among different contaminants in the environment. PMID:26930197

  5. Interactions between Silicon Oxide Nanoparticles (SONPs) and U(VI) Contaminations: Effects of pH, Temperature and Natural Organic Matters

    PubMed Central

    Wu, Hanyu; Li, Ping; Pan, Duoqiang; Yin, Zhuoxin; Fan, Qiaohui; Wu, Wangsuo

    2016-01-01

    The interactions between contaminations of U(VI) and silicon oxide nanoparticles (SONPs), both of which have been widely used in modern industry and induced serious environmental challenge due to their high mobility, bioavailability, and toxicity, were studied under different environmental conditions such as pH, temperature, and natural organic matters (NOMs) by using both batch and spectroscopic approaches. The results showed that the accumulation process, i.e., sorption, of U(VI) on SONPs was strongly dependent on pH and ionic strength, demonstrating that possible outer- and/or inner-sphere complexes were controlling the sorption process of U(VI) on SONPs in the observed pH range. Humic acid (HA), one dominated component of NOMs, bounded SONPs can enhance U(VI) sorption below pH~4.5, whereas restrain at high pH range. The reversible sorption of U(VI) on SONPs possibly indicated that the outer-sphere complexes were prevalent at pH 5. However, an irreversible interaction of U(VI) was observed in the presence of HA (Fig 1). It was mainly due to the ternary SONPs-HA-U(VI) complexes (Type A Complexes). After SONPs adsorbed U(VI), the particle size in suspension was apparently increased from ~240 nm to ~350 nm. These results showed that toxicity of both SONPs and U(VI) will decrease to some extent after the interaction in the environment. These findings are key for providing useful information on the possible mutual interactions among different contaminants in the environment. PMID:26930197

  6. Learning Disabilities or Teaching Disabilities? Rethinking Literacy Failure

    ERIC Educational Resources Information Center

    Applegate, Anthony J.; Applegate, Mary Dekonty; Turner, Jennifer D.

    2010-01-01

    It takes a literacy leader to save some schools and districts from serious misconceptions about the nature of core reading programs as well as the nature of some reading disabilities. Well-prepared professionals can, by means of their extensive pedagogical repertoire, help districts to avoid compulsive repetition of the same fundamental types of…

  7. 'Tagger' - a Mac OS X Interactive Graphical Application for Data Inference and Analysis of N-Dimensional Datasets in the Natural Physical Sciences.

    NASA Astrophysics Data System (ADS)

    Morse, P. E.; Reading, A. M.; Lueg, C.

    2014-12-01

    observations of important or noticeable events. Other visualisations and modes of interaction will also be demonstrated, with the aim of discovering knowledge in large datasets in the natural, physical sciences. Fig.1 Wave height data from an oceanographic Wave Rider Buoy. Colors/radii are driven by wave height data.

  8. Investigating the Heterogeneous Interaction of VOCs with Natural Atmospheric Particles: Adsorption of Limonene and Toluene on Saharan Mineral Dusts.

    PubMed

    Romanías, Manolis N; Ourrad, Habib; Thévenet, Frédéric; Riffault, Véronique

    2016-03-01

    The heterogeneous interaction of limonene and toluene with Saharan dusts was investigated under dark conditions, pressure of 1 atm, and temperature 293 K. The mineral dust samples were collected from six different regions along the Sahara desert, extending from Tunisia to the western Atlantic coastal areas of Morocco, and experiments were carried out with the smallest sieved fractions, that is, inferior to 100 μm. N2 sorption measurements, granulometric analysis, and X-ray fluorescence and diffraction (XRF and XRD) measurements were conducted to determine the physicochemical properties of the particles. The chemical characterization showed that dust originating from mideastern Sahara has a significantly higher SiO2 content (∼ 82%) than dust collected from the western coastal regions where the SiO2 relative abundance was ∼ 50%. A novel experimental setup combining diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), selected-ion flow-tube mass spectrometry (SIFT-MS), and long path transmission Fourier transform infrared spectroscopy (FTIR) allowed us to follow both the adsorbed and gas phases. The kinetic adsorption/desorption measurements were performed using purified dry air as bath gas, exposing each dust surface to 10 ppm of the selective volatile organic compound (VOC). The adsorption of limonene was independent of the SiO2 content, given the experimental uncertainties, and the coverage measurements ranged between (10 and 18) × 10(13) molecules cm(-2). Experimental results suggest that other metal oxides that could possibly influence dust acidity may enhance the adsorption of limonene. On the contrary, in the case of toluene, the adsorption capacities of the Saharan samples increased with decreasing SiO2 content; however, the coverage measurements were significantly lower than those of limonene and ranged between (2 and 12) × 10(13) molecules cm(-2). Flushing the surface with purified dry air showed that VOC desorption is not a

  9. 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. PMID:18604590

  10. The Nature of Plume-Ridge Interaction on the Mid-Atlantic Ridge south of the Azores

    NASA Astrophysics Data System (ADS)

    Gale, A.; Laubier, M.; Escrig, S.; Langmuir, C. H.

    2011-12-01

    Classical work in the 1970s established a gradient in ridge depth and chemical composition southwards from the Azores hot spot. Proximal basalts were enriched in highly incompatible elements and 87Sr/86Sr, and this enrichment decreased southwards until depleted MORB were encountered south of the Hayes fracture zone. This was explained through mantle source mixing, with the proportion of plume mantle decreasing with distance from the plume. Detailed maps of ocean ridges, however, show that ocean ridges consist of a series of segments that are shallow in their centers and deeper at their ends, so the "regional gradient" in depth actually consists of a series of undulations at various scales. The question then arises how the regional gradient in geochemistry is influenced by this segmentation. Detailed major element, trace element (TE) and isotopic study of over 200 samples from four segments south of the Azores platform allows a better assessment of the detailed characteristics of the geochemical gradient, with implications for plume-ridge interaction. All basalts from the KP-5 ("Menez Gwen"), PO-1 ("Lucky Strike"), PO-2 and PO-3 ("FAMOUS") segments (in order from north to south) are enriched relative to depleted MORB. While this enrichment is related to the Azores plume, as confirmed by the trends in isotope diagrams, there is much complexity in detail regarding how the enriched signature is imparted to the lavas. The KP-5 and PO-1 segments contain two groups of chemically distinct basalts. Moderately enriched basalts are found throughout the segments. At the segment centers highly enriched basalts with high concentrations of incompatible elements and an enriched isotopic signature predominate. Remarkably, incompatible element ratios (e.g. Ba/La, Nb/Zr) of these basalts are higher than basalts from the center of the Azores platform, while their isotopic values are less enriched. This dichotomy between TE ratios and isotopes of the highly enriched samples can be

  11. A Journey with Parents and Infants: Rethinking Parent Professional Interactions. An Early Intervention Training Manual.

    ERIC Educational Resources Information Center

    Hanson, Janice; Freund, Maxine B.

    This manual describes the results of a 3-year research project at George Washington University (District of Columbia) called the Assessment as Intervention Project, which explored approaches to parent-sensitive developmental follow-up for prematurely born infants who received neonatal intensive care and their families (N=25). After an…

  12. Rethinking Online Education: The Impact of Synchronous Telecommunication Interactions on Student Success

    ERIC Educational Resources Information Center

    Hibbard, Joshua A.

    2013-01-01

    Higher education leaders in the 21st century are faced with challenges of affordability, accessibility, and increased demand for postsecondary education. The recent growth of online educational programs in the United States provides institutions with potential solutions to these challenges; yet, persistence rates continue to lag behind traditional…

  13. The interaction between natural organic matter in raw waters and pesticide residues: a three dimensional excitation-emission matrix (3DEEM) fluorescence investigation.

    PubMed

    Beale, David J; Porter, Nichola A; Roddick, Felicity A

    2013-01-01

    This paper examines the interaction between dissolved natural organic matter and pesticide residues, both of which are found in raw water sources, using three dimensional excitation-emission matrix (3DEEM) fluorescence spectroscopy. It was observed that pesticide residue at 0.1 mg L(-1) formed a complex with humic-like fluorophores that are commonly found in raw water samples. Applying 3DEEM fluorescence to investigate the humic fractions, it was found that identification of changes in water sources was possible, and, importantly, the presence of a number of pesticides was able to be determined. In addition, the formation of this complex, and the influence of soluble cations and anions upon it, was shown to impact the efficiency of analytical extraction procedures for pesticides; however, 3DEEM fluorescence could be an approach to account for such losses. PMID:23752373

  14. The effect of long-term fluid-rock interactions on the mechanical properties of reservoir rock - a case study of the Werkendam natural CO2 analogue field

    NASA Astrophysics Data System (ADS)

    Hangx, Suzanne; Bertier, Pieter; Bakker, Elisenda; Nover, Georg; Busch, Andreas

    2015-04-01

    Geological storage of CO2 is one of the most promising technologies to rapidly reduce anthropogenic emissions of carbon dioxide. During long-term geological storage of CO2, fluid-rock interactions, induced by the formation of carbonic acid, may affect the mineralogical composition of the reservoir rock. Commonly expected reactions include the dissolution of carbonate and/or sulphate cements, as well as the reaction of primary minerals (feldspars, clays, micas) to form new, secondary phases. In order to ensure storage integrity, it is important to understand the effect of such fluid-rock interactions on the mechanical behaviour of a CO2 storage complex. However, most of these reactions are very slow, which limits the ability to study coupled chemical-mechanical processes in the lab. A possible way to circumvent long reaction times is to investigate natural CO2 analogue fields, which experienced CO2-exposure for thousands of years. In this study, we looked at the Dutch Werkendam natural CO2 field and its unreacted counterpart (Röt Fringe Sandstone, Werkendam, the Netherlands). We focussed on CO2-induced mineralogical and porosity-permeability changes, and their effect on mechanical behaviour of intact rock. Overall, CO2-exposure did not lead to drastic mineralogical changes, though markedly different porosity-permeability relationships were found for the unreacted and exposed material. The limited extent of reaction was in part the result of bitumen coatings protecting specific mineral phases from reaction. In local, mm-sized zones displaying significant anhydrite dissolution, enhanced porosity was observed. For most of the reservoir the long-term mechanical behaviour after CO2-exposure could be described by the behaviour of the unreacted sandstone, while these more 'porous' zones were significantly weaker. Simple stress path calculations predict that reservoir failure due to depletion and injection is unlikely.

  15. Fluid-structure interaction analysis and lifetime estimation of a natural gas pipeline centrifugal compressor under near-choke and near-surge conditions

    NASA Astrophysics Data System (ADS)

    Ju, Yaping; Liu, Hui; Yao, Ziyun; Xing, Peng; Zhang, Chuhua

    2015-11-01

    Up to present, there have been no studies concerning the application of fluid-structure interaction (FSI) analysis to the lifetime estimation of multi-stage centrifugal compressors under dangerous unsteady aerodynamic excitations. In this paper, computational fluid dynamics (CFD) simulations of a three-stage natural gas pipeline centrifugal compressor are performed under near-choke and near-surge conditions, and the unsteady aerodynamic pressure acting on impeller blades are obtained. Then computational structural dynamics (CSD) analysis is conducted through a one-way coupling FSI model to predict alternating stresses in impeller blades. Finally, the compressor lifetime is estimated using the nominal stress approach. The FSI results show that the impellers of latter stages suffer larger fluctuation stresses but smaller mean stresses than those at preceding stages under near-choke and near-surge conditions. The most dangerous position in the compressor is found to be located near the leading edge of the last-stage impeller blade. Compressor lifetime estimation shows that the investigated compressor can run up to 102.7 h under the near-choke condition and 200.2 h under the near-surge condition. This study is expected to provide a scientific guidance for the operation safety of natural gas pipeline centrifugal compressors.

  16. Theoretical investigations on the layer-anion interaction in Mg-Al layered double hydroxides: Influence of the anion nature and layer composition

    NASA Astrophysics Data System (ADS)

    Cuautli, Cristina; Ireta, Joel

    2015-03-01

    The influence of the anion nature and layer composition on the anion-layer interaction in Mg-Al layered double hydroxides (LDHs) is investigated using density functional theory. Changes in the strength of the anion-layer interaction are assessed calculating the potential energy surface (PES) associated to the interlayer anion (OH-/Cl-) in Mg-Al-OH and Mg-Al-Cl LDHs. The layer composition is varied changing the divalent to trivalent cation proportion (R). Mg-Al-OH is thus investigated with R = 2, 3, 3.5 and Mg-Al-Cl with R = 3. It is found that the PES for OH- in Mg-Al-OH/R = 3 presents wider energy basins and lower energy barriers than any other of the investigated compositions. It is shown that the latter is connected to the number of hydrogen bonds formed by the anions. These results have interesting implications for understanding the enhancement of the physicochemical properties of LDHs upon changing composition.

  17. Computational Docking Study of p7 Ion Channel from HCV Genotype 3 and Genotype 4 and Its Interaction with Natural Compounds

    PubMed Central

    Mathew, Shilu; Fatima, Kaneez; Fatmi, M. Qaiser; Archunan, Govindaraju; Ilyas, Muhammad; Begum, Nargis; Azhar, Esam; Damanhouri, Ghazi; Qadri, Ishtiaq

    2015-01-01

    Background The current standard care therapy for hepatitis C virus (HCV) infection consists of two regimes, namely interferon-based and interferon-free treatments. The treatment through the combination of ribavirin and pegylated interferon is expensive, only mildly effective, and is associated with severe side effects. In 2011, two direct-acting antiviral (DAA) drugs, boceprevir and telaprevir, were licensed that have shown enhanced sustained virologic response (SVR) in phase III clinical trial, however, these interferon-free treatments are more sensitive to HCV genotype 1 infection. The variable nature of HCV, and the limited number of inhibitors developed thus aim in expanding the repertoire of available drug targets, resulting in targeting the virus assembly therapeutically. Aim We conducted this study to predict the 3D structure of the p7 protein from the HCV genotypes 3 and 4. Approximately 63 amino acid residues encoded in HCV render this channel sensitive to inhibitors, making p7 a promising target for novel therapies. HCV p7 protein forms a small membrane known as viroporin, and is essential for effective self-assembly of large channels that conduct cation assembly and discharge infectious virion particles. Method In this study, we screened drugs and flavonoids known to disrupt translation and production of HCV proteins, targeted against the active site of p7 residues of HCV genotype 3 (GT3) (isolatek3a) and HCV genotype 4a (GT4) (isolateED43). Furthermore, we conducted a quantitative structure–activity relationship and docking interaction study. Results The drug NB-DNJ formed the highest number of hydrogen bond interactions with both modeled p7 proteins with high interaction energy, followed by BIT225. A flavonoid screen demonstrated that Epigallocatechin gallate (EGCG), nobiletin, and quercetin, have more binding modes in GT3 than in GT4. Thus, the predicted p7 protein molecule of HCV from GT3 and GT4 provides a general avenue to target structure

  18. Toward re-thinking science education in terms of affective practices: reflections from the field

    NASA Astrophysics Data System (ADS)

    Kayumova, Shakhnoza; Tippins, Deborah

    2016-06-01

    Rational and operationalized views of science and what it means for teachers and students to know and enact legitimate science practices have dominated science education research for many decades (Fusco and Barton in J Res Sci Teach 38(3):337-354, 2001. doi: 10.1002/1098-2736(200103)38:3<337::AID-TEA1009>3.0.CO;2-0). Michalinos Zembylas challenges historically prevalent dichotomies of mind/body, reason/emotion, and emotion/affect, calling researchers and educators to move beyond the Cartesian dualisms, which have perpetuated a myth of scientific objectivity devoid of bias, subjectivity and emotions. Zembylas (Crit Stud Teach Learn 1(1):1-21, 2013. doi: 10.14426/cristal.v1i1.2) contends that the role of emotions and affect are best understood as relational and entangled in epistemological, cultural, and historical contexts of education, which represent contested sites of control and resistance. We argue that Zembylas' work is pivotal since "theoretical frames of reference for doing research in science education…[and] what constitutes knowledge and being within a particular frame" carry material bearings over the enactments of science teaching and learning (Kyle in J Res Sci Teach 31:695-696, 1994, p. 321. doi: 10.1002/tea.3660310703). In this paper, we hold cogen dialogue about how re-thinking notions of emotion and affect affords us, both science educators and researchers, to re-envision science education beyond cognitive and social frames. The framing of our dialogue as cogen builds on Wolff-Michael Roth and Kenneth Tobin's (At the elbows of another: learning to teach through coteaching. Peter Lang Publishing, New York, 2002) notion of cogenerative dialogue. Holding cogen is an invitation to an openly dialogic and safe area, which serves as a space for a dialogic inquiry that includes radical listening of situated knowledges and learning from similarities as well as differences of experiences (Tobin in Cult Stud Sci Educ, in review, 2015). From our situated

  19. Rethinking Adolescent Risk-Taking Behavior and the Peer Leader Dynamic.

    ERIC Educational Resources Information Center

    Carter, D. S. G.; And Others

    The nature of the interactions that occur among peer leaders, peer influence, and the dynamics of the peer reference group in the context of health, interpersonal relations and lifestyle choice were the subjects of this study. Its first stage (of two) employed a case study of a single metropolitan senior high school in Australia. Adolescent peer…

  20. Encounters between the "Oppressed" and the "Oppressor": Rethinking Paulo Freire in Anti-Racist Feminist Education in Sweden

    ERIC Educational Resources Information Center

    Yang, Chia-Ling

    2016-01-01

    With the aim of rethinking Paulo Freire's theory and its practices in race/ethnicity and education, this article uses intersectionality to deepen our understanding of differences among the oppressed and break the opposition between the oppressed and oppressor. Based on an ethnographic study carried out at a feminist adult educational institution…

  1. Backgrounder. Rethinking Science and Society: Public Survey by EKOS Research Associates. Canadians See Clear-Cut Benefits to University Research

    ERIC Educational Resources Information Center

    Association of Universities and Colleges of Canada, 2004

    2004-01-01

    Between August and September 2004, EKOS Research Associates conducted the first round of a study entitled, Rethinking Science and Society. The aim of this study is to assess Canadians' attitudes toward science and research, particularly since research and innovation policies have become increasingly important for the federal government. The…

  2. Review of "Expanding Choice in Elementary and Secondary Education: A Report on Rethinking the Federal Role in Education"

    ERIC Educational Resources Information Center

    Scott, Janelle

    2010-01-01

    "Expanding Choice in Elementary and Secondary Education: A Report on Rethinking the Federal Role in Education" presents a seemingly egalitarian prescription for the federal government to expand school choice. An examination of the arguments and evidence for increasing choice, however, reveals at least three important shortcomings. First, the…

  3. Steer, Row or Abandon Ship? Rethinking the Federal Role for Children, Youth & Families. Special Report No. 8.

    ERIC Educational Resources Information Center

    Dunkle, Margaret C.

    Based on 1996 testimony by Margaret Dunkle, director of the Institute of Educational Leadership (IEL) Policy Exchange, before the U.S. House of Representatives Subcommittee on Early Childhood, Youth and Families, this report calls for a rethinking of the federal role for children, youth, and families, encouraging the federal government to "steer"…

  4. One Starfish at a Time: Using Fundamentals in Sociology to Rethink Impressions about People Living with HIV/AIDS

    ERIC Educational Resources Information Center

    Moremen, Robin D.

    2010-01-01

    The purpose of this article is to document how a course in the fundamentals of sociology encouraged students to rethink negative impressions about people with AIDS. Multimethod, active learning processes were utilized to introduce the sociological imagination, critical thinking, and theory and methods in sociology. The intent was to apply basic…

  5. Rethinking Education in the Age of Technology: The Digital Revolution and Schooling in America. Technology, Education--Connections (TEC) Series

    ERIC Educational Resources Information Center

    Collins, Allan; Halverson, Richard

    2009-01-01

    The digital revolution has hit education, with more and more classrooms plugged into the whole wired world. But are schools making the most of new technologies? Are they tapping into the learning potential of today's Firefox/Facebook/cell phone generation? Have schools fallen through the crack of the digital divide? In "Rethinking Education in the…

  6. Important Issues, Some Rhetoric, and a Few Straw Men: A Response to Comments on "Rethinking Giftedness and Gifted Education"

    ERIC Educational Resources Information Center

    Worrell, Frank C.; Olszewski-Kubilius, Paula; Subotnik, Rena F.

    2012-01-01

    In this article, the authors respond to the eight commentaries on "Rethinking Giftedness and Gifted Education: A Proposed Direction Forward Based on Psychological Science" using several themes to organize their response. These themes include ability, developmental trajectories, effort and opportunity, psychosocial factors, eminence, and equity.…

  7. Rethinking the Development of Weapons and Their Impact

    ERIC Educational Resources Information Center

    Katsioloudis, Petros J.; Jones, Mildred V.

    2011-01-01

    As one reads about the history of humans, he/she sees very early on that humans are naturally "tool users." More specifically, humans used tools as a means of subsistence and survival. Even today humans use tools to extend their capabilities beyond imagination. These tools are even used as weapons. However primitive, these early weapons would soon…

  8. Rethinking General Education in the English Upper Secondary System

    ERIC Educational Resources Information Center

    Hodgson, Ann; Spours, Ken

    2011-01-01

    The Secretary of State for Education's recent announcement of an English Baccalaureate at 16+ has opened up a debate about the nature of general education in the English upper secondary system. Drawing on evidence from national and local studies, we argue that it is important to see general education in England, not only in terms of the…

  9. Re-Thinking Green - Alternatives to Environmental Bureaucracy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The majority of environmental scientists active today are familiar with the key tenets of landmark environmental legislation (e.g. Clean Air Act and Endangered Species Act) and the associated guidelines that delineate the current framework for natural resource management. This book challenges the r...

  10. Mobile Learning: Rethinking the Future of Journalism Practice and Pedagogy

    ERIC Educational Resources Information Center

    Walck, Pamela E.; Cruikshank, Sally Ann; Kalyango, Yusuf, Jr.

    2015-01-01

    Despite the proliferation of mobile devices, there is limited awareness of how journalism students are prepared for the evolving nature of the workplace in regard to mobile devices and how journalism professionals utilize this technology in daily routines. This study examines how journalism educators, students, and practitioners embrace the…

  11. Rethinking Respite Policy for People with Intellectual and Developmental Disabilities

    ERIC Educational Resources Information Center

    Chan, Jeffrey; Merriman, Brian; Parmenter, Trevor; Stancliffe, Roger

    2012-01-01

    Respite care is one of a range of support services typically available to carers of people with dependencies who need a break from caring, and the factors that influence the need for respite care are generally similar irrespective of the nature of the dependencies. Hence, the expectations of families potentially have policy and service provision…

  12. Rethinking Business Education as a Profession: Implications for Catholic Universities

    ERIC Educational Resources Information Center

    Sullivan, William M.

    2013-01-01

    Professional education importantly shapes the way future professionals understand their work and their identity as members of their professional field. Undergraduate business education does this by giving students an understanding of the nature and functions of business as well as what they may hope for from a business career, along with the…

  13. Shrek Meets Vygotsky: Rethinking Adolescents' Multimodal Literacy Practices in Schools

    ERIC Educational Resources Information Center

    Mills, Kathy A.

    2010-01-01

    Recent research has emphasized the multimodal and digital nature of adolescent literacy practices. These practices cross multiple social spaces, particularly settings outside of schools. This article re-examines current research to yield three caveats that counter assumptions about the pervasiveness, relevance, and spontaneity of youths'…

  14. Rethinking Combined Departments: An Argument for History and Anthropology

    ERIC Educational Resources Information Center

    Sluis, Ageeth; Edwards, Elise

    2013-01-01

    Many opportunities for more integrated teaching that better capture the interdisciplinary nature of contemporary scholars' work and better achieve the aims of liberal arts education still remain untapped, particularly at smaller schools where combined departments are often necessary. The disciplinary boundaries between history and…

  15. Rethinking Critical Thinking and Its Role in Art Museum Education

    ERIC Educational Resources Information Center

    Hubard, Olga

    2011-01-01

    Meaningful interactions with works of art are often absent from education. Across the country, art museums are intent on changing this situation. But to incorporate art viewing into an educational milieu that does not value art, art museum educators are constantly forced to justify the educational value of their programs. One common argument to…

  16. Nativism versus Neuroconstructivism: Rethinking the Study of Developmental Disorders

    ERIC Educational Resources Information Center

    Karmiloff-Smith, Annette

    2009-01-01

    This article argues that one dominant position in psychology, linguistics, neuroscience, and philosophy about how genetic disorders point to the innate specification of dissociated modules in the human brain should be replaced by a dynamic, neuroconstructivist approach in which genes, brain, cognition, and environment interact multidirectionally.…

  17. Numerical Simulation of The Mediterranean Sea Using Diecast: Interaction Between Basin, Sub-basin and Local Scale Features and Natural Variability.

    NASA Astrophysics Data System (ADS)

    Fernández, V.; Dietrich, D. E.; Haney, R. L.; Tintoré, J.

    In situ and satellite data obtained during the last ten years have shown that the circula- tion in the Mediterranean Sea is extremely complex in space, with significant features ranging from mesoscale to sub-basin and basin scale, and highly variable in time, with mesoscale to seasonal and interannual signals. Also, the steep bottom topography and the variable atmospheric conditions from one sub-basin to another, make the circula- tion to be composed of numerous energetic and narrow coastal currents, density fronts and mesoscale structures that interact at sub-basin scale with the large scale circula- tion. To simulate numerically and better understand these features, besides high grid resolution, a low numerical dispersion and low physical dissipation ocean model is required. We present the results from a 1/8z horizontal resolution numerical simula- tion of the Mediterranean Sea using DieCAST ocean model, which meets the above requirements since it is stable with low general dissipation and uses accurate fourth- order-accurate approximations with low numerical dispersion. The simulations are carried out with climatological surface forcing using monthly mean winds and relax- ation towards climatological values of temperature and salinity. The model reproduces the main features of the large basin scale circulation, as well as the seasonal variabil- ity of sub-basin scale currents that are well documented by observations in straits and channels. In addition, DieCAST brings out natural fronts and eddies that usually do not appear in numerical simulations of the Mediterranean and that lead to a natural interannual variability. The role of this intrinsic variability in the general circulation will be discussed.

  18. Investigation of Solute-Fiber Affinity and Orientational Ordering of Norbornadiene Interacting with Two-Polypeptide Chiral Liquid Crystalline Solvents by Natural Abundance Deuterium (NAD) NMR.

    PubMed

    Serhan, Zeinab; Aroulanda, Christie; Lesot, Philippe

    2016-08-01

    A prochiral bridged compound of C2v symmetry, the norbornadiene (NBD), oriented in a chiral liquid crystal composed of various mixtures of poly-γ-benzyl-l-glutamate (PBLG) and poly-ε-carboxy-l-lysine (PCBLL), two chiral homopolypeptides, is investigated using natural abundance deuterium 2D-NMR (NAD 2D-NMR) spectroscopy. In such chiral oriented solvents, enantiotopic directions are spectrally nonequivalent, and two distinct (2)H quadrupolar doublets associated with enantioisotopomeric pairs of NBD are detected. As the two homopolypeptides have the same absolute configuration but distinct chemical functions in their side chains, the variation of residual quadrupolar couplings (RQC's) allows the determination of the relative solute-fiber affinities toward the two polypeptides in these lyotropic bipolymeric systems. Besides the experimental measurement of RQC's and the determination of their signs at each inequivalent (2)H site, the elements of the second-rank order tensor, Sαβ, are calculated by assuming a modeled structure. The variations of RQC's and diagonalized order parameters, Sα'α', are followed versus the relative proportion of two polypeptides in the chiral oriented mixture. The influence of the solute mass fraction in the two-homopolypeptide oriented samples is also examined as well as the case of homogeneous and uniform achiral mesophases "PBG-PCBL" made of two pairs of mirror-image homopolypeptides (PBLG/PBDG and PCBLL/PCBDL). In the latter, the solute ordering is modulated by the proportion of each type of homopolypeptide (chemical nature and absolute configuration), leading to eliminate the enantiodiscrimination mechanisms on the average. In the frame of a model, new insights on the solute-homopolypeptide fiber interactions are discussed. PMID:27383731

  19. The Darwinian revolution: Rethinking its meaning and significance

    PubMed Central

    Ruse, Michael

    2009-01-01

    The Darwinian revolution is generally taken to be one of the key events in the history of Western science. In recent years, however, the very notion of a scientific revolution has come under attack, and in the specific case of Charles Darwin and his Origin of Species there are serious questions about the nature of the change (if there was such) and the specifically Darwinian input. This article considers these issues by addressing these questions: Was there a Darwinian revolution? That is, was there a revolution at all? Was there a Darwinian revolution? That is, what was the specific contribution of Charles Darwin? Was there a Darwinian revolution? That is, what was the conceptual nature of what occurred on and around the publication of the Origin? I argue that there was a major change, both scientifically and in a broader metaphysical sense; that Charles Darwin was the major player in the change, although one must qualify the nature and the extent of the change, looking particularly at things in a broader historical context than just as an immediate event; and that the revolution was complex and we need the insights of rather different philosophies of scientific change to capture the whole phenomenon. In some respects, indeed, the process of analysis is still ongoing and unresolved. PMID:19528652

  20. The Nature of Secondary Interactions at Electrophilic Metal Sites of Molecular and Silica-Supported Organolutetium Complexes from Solid-State NMR Spectroscopy.

    PubMed

    Conley, Matthew P; Lapadula, Giuseppe; Sanders, Kevin; Gajan, David; Lesage, Anne; del Rosal, Iker; Maron, Laurent; Lukens, Wayne W; Copéret, Christophe; Andersen, Richard A

    2016-03-23

    Lu[CH(SiMe3)2]3 reacts with [SiO2-700] to give [(≡SiO)Lu[CH(SiMe3)2]2] and CH2(SiMe3)2. [(≡SiO)Lu[CH(SiMe3)2]2] is characterized by solid-state NMR and EXAFS spectroscopy, which show that secondary Lu···C and Lu···O interactions, involving a γ-CH3 and a siloxane bridge, are present. From X-ray crystallographic analysis, the molecular analogues Lu[CH(SiMe3)2]3-x[O-2,6-tBu-C6H3]x (x = 0-2) also have secondary Lu···C interactions. The (1)H NMR spectrum of Lu[CH(SiMe3)2]3 shows that the -SiMe3 groups are equivalent to -125 °C and inequivalent below that temperature, ΔG(⧧)(Tc = 148 K) = 7.1 kcal mol(-1). Both -SiMe3 groups in Lu[CH(SiMe3)2]3 have (1)JCH = 117 ± 1 Hz at -140 °C. The solid-state (13)C CPMAS NMR spectrum at 20 °C shows three chemically inequivalent resonances in the area ratio of 4:1:1 (12:3:3); the J-resolved spectra for each resonance give (1)JCH = 117 ± 2 Hz. The (29)Si CPMAS NMR spectrum shows two chemically inequivalent resonances with different values of chemical shift anisotropy. Similar observations are obtained for Lu[CH(SiMe3)2]3-x[O-2,6-tBu-C6H3]x (x = 1 and 2). The spectroscopic data point to short Lu···Cγ contacts corresponding to 3c-2e Lu···Cγ-Siβ interactions, which are supported by DFT calculations. Calculated natural bond orbital (NBO) charges show that Cγ carries a negative charge, while Lu, Hγ, and Siβ carry positive charges; as the number of O-based ligands increases so does the positive charge at Lu, which in turns shortens the Lu···Cγ distance. The change in NBO charges and the resulting changes in the spectroscopic and crystallographic properties show how ligands and surface-support sites rearrange to accommodate these changes, consistent with Pauling's electroneutrality concept. PMID:26887899