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Sample records for dispersal anachronisms rethinking

  1. Seed Dispersal Anachronisms: Rethinking the Fruits Extinct Megafauna Ate

    OpenAIRE

    Guimarães, Paulo R.; Galetti, Mauro; Jordano, Pedro

    2008-01-01

    Background: Some neotropical, fleshy-fruited plants have fruits structurally similar to paleotropical fruits dispersed by megafauna (mammals .103 kg), yet these dispersers were extinct in South America 10–15 Kyr BP. Anachronic dispersal systems are best explained by interactions with extinct animals and show impaired dispersal resulting in altered seed dispersal dynamics. Methodology/Principal Findings: We introduce an operational definition of megafaunal fruits and perform a comparativ...

  2. Seed dispersal anachronisms: rethinking the fruits extinct megafauna ate.

    Directory of Open Access Journals (Sweden)

    Paulo R Guimarães

    Full Text Available BACKGROUND: Some neotropical, fleshy-fruited plants have fruits structurally similar to paleotropical fruits dispersed by megafauna (mammals > 10(3 kg, yet these dispersers were extinct in South America 10-15 Kyr BP. Anachronic dispersal systems are best explained by interactions with extinct animals and show impaired dispersal resulting in altered seed dispersal dynamics. METHODOLOGY/PRINCIPAL FINDINGS: We introduce an operational definition of megafaunal fruits and perform a comparative analysis of 103 Neotropical fruit species fitting this dispersal mode. We define two megafaunal fruit types based on previous analyses of elephant fruits: fruits 4-10 cm in diameter with up to five large seeds, and fruits > 10 cm diameter with numerous small seeds. Megafaunal fruits are well represented in unrelated families such as Sapotaceae, Fabaceae, Solanaceae, Apocynaceae, Malvaceae, Caryocaraceae, and Arecaceae and combine an overbuilt design (large fruit mass and size with either a single or few ( 100 seeds. Within-family and within-genus contrasts between megafaunal and non-megafaunal groups of species indicate a marked difference in fruit diameter and fruit mass but less so for individual seed mass, with a significant trend for megafaunal fruits to have larger seeds and seediness. CONCLUSIONS/SIGNIFICANCE: Megafaunal fruits allow plants to circumvent the trade-off between seed size and dispersal by relying on frugivores able to disperse enormous seed loads over long-distances. Present-day seed dispersal by scatter-hoarding rodents, introduced livestock, runoff, flooding, gravity, and human-mediated dispersal allowed survival of megafauna-dependent fruit species after extinction of the major seed dispersers. Megafauna extinction had several potential consequences, such as a scale shift reducing the seed dispersal distances, increasingly clumped spatial patterns, reduced geographic ranges and limited genetic variation and increased among

  3. Rethinking the dispersal of Homo sapiens out of Africa.

    Science.gov (United States)

    Groucutt, Huw S; Petraglia, Michael D; Bailey, Geoff; Scerri, Eleanor M L; Parton, Ash; Clark-Balzan, Laine; Jennings, Richard P; Lewis, Laura; Blinkhorn, James; Drake, Nick A; Breeze, Paul S; Inglis, Robyn H; Devès, Maud H; Meredith-Williams, Matthew; Boivin, Nicole; Thomas, Mark G; Scally, Aylwyn

    2015-01-01

    Current fossil, genetic, and archeological data indicate that Homo sapiens originated in Africa in the late Middle Pleistocene. By the end of the Late Pleistocene, our species was distributed across every continent except Antarctica, setting the foundations for the subsequent demographic and cultural changes of the Holocene. The intervening processes remain intensely debated and a key theme in hominin evolutionary studies. We review archeological, fossil, environmental, and genetic data to evaluate the current state of knowledge on the dispersal of Homo sapiens out of Africa. The emerging picture of the dispersal process suggests dynamic behavioral variability, complex interactions between populations, and an intricate genetic and cultural legacy. This evolutionary and historical complexity challenges simple narratives and suggests that hybrid models and the testing of explicit hypotheses are required to understand the expansion of Homo sapiens into Eurasia. © 2015 Wiley Periodicals, Inc.

  4. Anachronism and the rewriting of history: the South Africa case

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    Georgi Verbeeck

    2006-04-01

    Full Text Available The use and abuse of anachronism is often seen as the quintessence of the writing of history. Historians tend to conceive it as the hardcore of their métier to avoid anachronism. It designates a confusion in order of time, especially the mistake of placing an event, attitude, or circumstance too early. The awareness of historical anachronism is omnipresent in times of a radical rewriting of history, in particular as a result of political transformation. History reflects the needs and ambitions of a political context, and the sense of what is deemed historically significant does not remain unattached hereby. Chronology and anachronism are essential to particular conceptions of history, and if history is in a process of being rewritten, they are the first items to be addressed by the defenders of the old system and the advocates of a new discourse. In political debates on the use or abuse of history anachronism is often seen as ultimate proof of the (un-reliability of new insights and conceptions. As anachronism is defined as a way of transferring contemporary sets of values, assumptions and interpretative categories, every political reorientation inevitably provokes a discussion on that level. If a ‘new nation’ is in search of a ‘new past’, a new reflection on the basic categories of historical thinking becomes necessary. The changing discourses in South African historiography since the end of Apartheid serve here as an illuminative example.

  5. Textures of Time. A Study of Cinematic Sensations of Anachronism

    NARCIS (Netherlands)

    Wortel, E.D.N.

    2008-01-01

    This research project presents a nonlinear method of encounters to investigate and affirm the spatial effects of anachronism on our traditional sensation of time in four unique and inventive cinematographic representations of the past: Elizabeth (Kapur 1998), Moulin Rouge (Luhrmann 2001), Russian

  6. Decolonizing Queer time: a critique of anachronism in latin@ writings

    Directory of Open Access Journals (Sweden)

    Eliana de Souza Avila

    2017-01-01

    Full Text Available http://dx.doi.org/10.5007/2175-8026.2017v70n1p39 While the term Latin@ is untraceable to any coherent referent in terms of geographical or epistemic origin (Rodríguez 2014, still it denotes a very stable referent when it comes to geographical destination — the USA being the central migratory destiny shaped by and shaping identity shifts and epistemic positions variously associated with Latin America. As much as this narrative determinacy is the effect of global power asymmetries, it also tends to naturalize them by couching migration in evolutionist terms that anachronize struggles against displacement, deterritorialization, and dispossession. The field of Latin@ literature and criticism therefore becomes an effective locus from which the ongoing historical conflicts elided by those narratives can be creatively recalled and reconfigured. This essay reflects on the temporal borderlands as a critical paradigm for reconfiguring narratives of straight temporality within Latin@ texts.

  7. Ecological anachronisms in the recruitment of temperate light-demanding tree species in wooded pastures

    NARCIS (Netherlands)

    Bakker, ES; Olff, H; Vandenberghe, C; De Maeyer, K; Smit, R; Gleichman, JM; Vera, FWM

    1. Light-demanding trees and thorny shrubs in temperate plant communities may reflect adaptations to now-extinct large grazers, such as aurochs and tarpans, rendering these adaptations ecological anachronisms. 2. We explored the ecological functions of plant traits of Quercus robur and Prunus

  8. Re-Thinking the Two-Body Problem: The Segregation of Women into Geographically-Dispersed Occupations

    Science.gov (United States)

    Benson, Alan

    2014-01-01

    Empirical research on the family cites the tendency for couples to relocate for husbands’ careers as evidence against the gender-neutrality of household economic decisions. For these studies, occupational segregation is a concern because occupations are not random by sex and mobility is not random by occupation. I find the tendency for households to relocate for husbands’ careers is better-explained by the segregation of women into geographically-dispersed occupations rather than by the direct prioritization of men’s careers. Among never-married workers, women relocate for work less-often than men and the gender effect disappears after accounting for occupational segregation. While most two-earner families feature husbands in geographically-clustered jobs involving frequent relocation for work, families are no-less-likely to relocate for work when it belongs to the wife. I conclude future research in household mobility should treat occupational segregation occurring prior to marriage rather than gender bias within married couples as the primary explanation for the prioritization of husbands’ careers in household mobility decisions. PMID:25189156

  9. Rethinking Diversity.

    Science.gov (United States)

    1996

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

  10. The Uses of Anachronism in Shakespeare’s Troilus and Cressida

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    Evrim Doğan ADANUR

    2017-10-01

    Full Text Available Written at the turn of the century, Troilus and Cressida includes different codes of conduct in relation to those belonging to the past and the contemporary. In the play, the fading away ideals of the chivalric age are represented by the Trojan Hector and of the modern by the Greek Ulysses. William Shakespeare, by juxtaposing the medieval/feudal and the modern/capitalist in this play, employs an anachronistic approach to looking at the past and the present. In his version of the most famous story of war and valour in the Western tradition, Shakespeare problematizes the linear view of history and offers a kairotic understanding of historical difference not only by carrying contemporary forms of behavior and thought to the past but also by showing the anachronism of trying to be chivalric in the modern age. This necessary anachronism lets Shakespeare make a comment on the early modern ideology in his retelling of the seemingly Homeric tale that reached to the Renaissance in an altered form through the romance tradition.

  11. Rethinking schizophrenia.

    Science.gov (United States)

    Insel, Thomas R

    2010-11-11

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

  12. Rethinking Creativity

    DEFF Research Database (Denmark)

    Despite more than half a century of psychological research on creativity we are still far from a clear understanding of the creative process, its antecedents and consequences and, most of all, the ways in which we can effectively support creativity. This is primarily due to a narrow focus...... on creative individuals isolated from culture and society. Rethinking Creativity proposes a fundamental review of this position and argues that creativity is not only a psychological but a sociocultural phenomenon. This edited volume aims to relocate creativity from inside individual minds to the material......, symbolic and social world of culture. It brings together eminent social and cultural psychologists who study dynamic, transformative and emergent phenomena, and invites them to conceptualise creativity in ways that depart from mainstream definitions and theoretical models existing in past and present...

  13. The Anachronism of the Local Public Accountancy Determinate by the Accrual European Model

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    Riana Iren RADU

    2009-01-01

    Full Text Available Placing the European accrual model upon cash accountancy model,presently used in Romania, at the level of the local communities, makespossible that the anachronism of the model to manifest itself on the discussion’sconcentration at the nominalization about the model’s inclusion in everydaypublic practice. The basis of the accrual model were first defined in the lawregarding the commercial societies adopted in Great Britain in 1985, when theydetermined that all income and taxes referring to the financial year “will betaken into consideration without any boundary to the reception or paymentdate.”1 The accrual model in accountancy needs the recording of the non-casheffects in transactions or financial events for their appearance periods and not inany generated cash, received or paid. The business development was the basisfor “sophistication” of the recordings of the transactions and financial events,being prerequisite for recording the debtors’ or creditors’ sums.

  14. Forms of presentism in the history of science. Rethinking the project of historical epistemology.

    Science.gov (United States)

    Loison, Laurent

    2016-12-01

    Since the late 1980s, presentism has seen a resurgence among some historians of science. Most of them draw a line between a good form of presentism and typical anachronism, but where the line should be drawn remains an open question. The present article aims at resolving this problem. In the first part I define the four main distinct forms of presentism at work in the history of science and the different purposes they serve. Based on this typology, the second part reconsiders what counts as anachronism, Whiggism and positivist history. This clarification is used as a basis to rethink the research program of historical epistemology in the third section. Throughout this article, I examine the conceptual core of historical epistemology more than its actual history, from Bachelard to Foucault or others. Its project should be defined - as Canguilhem suggested - as an attempt to account for both the contingency and the rationality of science. As such, historical epistemology is based on a complex fifth form of presentism, which I call critical presentism. The critical relation at stake not only works from the present to the past, because of the acknowledged rationality of science, but also from the past to the present because of the contingency and historicity of scientific knowledge. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Rethinking image indexing?

    DEFF Research Database (Denmark)

    Christensen, Hans Dam

    2017-01-01

    Hans Dam Christensen, ”Rethinking image indexing?”, in: Journal of the Association for Information Science and Technology, vol. 68, no. 7, 2017, 1782-1785......Hans Dam Christensen, ”Rethinking image indexing?”, in: Journal of the Association for Information Science and Technology, vol. 68, no. 7, 2017, 1782-1785...

  16. Haiti’s first national pavilion at the Venice Biennale: anachronism or illuminating opportunity?

    Directory of Open Access Journals (Sweden)

    Wendy Asquith

    2014-02-01

    Full Text Available A barrage of criticism has been levelled against the Venice Biennale’s national pavilion structure in recent decades, chiefly accusing it of anachronism on account of its western biases. Yet the tide has begun to turn, making much of this criticism sound a little worn-out. As this event increasingly attracts debuting ‘non-western’ national exhibitors each year, its pavilion structure event is beginning to be reassessed. Haiti was one such debutant at the 54th edition of La Biennale di Venezia held in 2011. This article will explore in detail the debates raised by Haiti’s national pavilion, particularly as they related to the central exhibition theme of ILLUMInations selected by the International Art Exhibition Director for 2011, Bice Curiger. In doing so this piece will consider both: how the national pavilion structure at the Venice Biennale was challenged, and our wider understanding of it deepened, by Haiti’s participation; and what Venice’s national pavilion structure might be able to offer a post-colonial, ‘third-world’ nation like Haiti.

  17. Rethinking Education and Poverty

    Science.gov (United States)

    Tierney, William G., Ed.

    2015-01-01

    In "Rethinking Education and Poverty," William G. Tierney brings together scholars from around the world to examine the complex relationship between poverty and education in the twenty first century. International in scope, this book assembles the best contemporary thinking about how education can mediate class and improve the lives of…

  18. Rethinking e-learning

    DEFF Research Database (Denmark)

    Bang, Jørgen; Dalsgaard, Christian

    2006-01-01

    “Technology alone does not deliver educational success. It only becomes valuable in education if learners and teachers can do something useful with it” (E-Learning: The Partnership Challenge, 2001, p. 24). This quotation could be used as a bon mot for this chapter. Our main goal is to rethink e-learning...... by shifting the focus of attention from learning resources (learning objects) to learning activities, which also implies a refocusing of the pedagogical discussion of the learning process.Firstly, we try to identify why e-learning has not been able to deliver the educational results as expected five years ago...

  19. Rethinking Project Management in Denmark

    DEFF Research Database (Denmark)

    Svejvig, Per

    2012-01-01

    . The chapter argues for a rethinking process due to pervasiveness and complexity in the contemporary project environment where rethinking is needed in order to stay competitive. The suggested approach for the rethinking project management is a framing process where body of ideas is established......Projects are everywhere across different sectors, industries and countries. Project management is no longer a sub-discipline of engineering and other rather technical disciplines but is also used for many other purposes. Even though practice has changed dramatically over the years, the models...... and methodologies for project management has been fairly static and has therefore received substantial criticism for a lack of relevance to practice. Several scholars have therefore started to think more widely about projects and project management conceptualized as rethinking project management. However this theme...

  20. Gourds and squashes (Cucurbita spp.) adapted to megafaunal extinction and ecological anachronism through domestication.

    Science.gov (United States)

    Kistler, Logan; Newsom, Lee A; Ryan, Timothy M; Clarke, Andrew C; Smith, Bruce D; Perry, George H

    2015-12-08

    The genus Cucurbita (squashes, pumpkins, gourds) contains numerous domesticated lineages with ancient New World origins. It was broadly distributed in the past but has declined to the point that several of the crops' progenitor species are scarce or unknown in the wild. We hypothesize that Holocene ecological shifts and megafaunal extinctions severely impacted wild Cucurbita, whereas their domestic counterparts adapted to changing conditions via symbiosis with human cultivators. First, we used high-throughput sequencing to analyze complete plastid genomes of 91 total Cucurbita samples, comprising ancient (n = 19), modern wild (n = 30), and modern domestic (n = 42) taxa. This analysis demonstrates independent domestication in eastern North America, evidence of a previously unknown pathway to domestication in northeastern Mexico, and broad archaeological distributions of taxa currently unknown in the wild. Further, sequence similarity between distant wild populations suggests recent fragmentation. Collectively, these results point to wild-type declines coinciding with widespread domestication. Second, we hypothesize that the disappearance of large herbivores struck a critical ecological blow against wild Cucurbita, and we take initial steps to consider this hypothesis through cross-mammal analyses of bitter taste receptor gene repertoires. Directly, megafauna consumed Cucurbita fruits and dispersed their seeds; wild Cucurbita were likely left without mutualistic dispersal partners in the Holocene because they are unpalatable to smaller surviving mammals with more bitter taste receptor genes. Indirectly, megafauna maintained mosaic-like landscapes ideal for Cucurbita, and vegetative changes following the megafaunal extinctions likely crowded out their disturbed-ground niche. Thus, anthropogenic landscapes provided favorable growth habitats and willing dispersal partners in the wake of ecological upheaval.

  1. Rethinking the mathematics curriculum

    CERN Document Server

    Hoyles, Celia; Woodhouse, Geoffrey

    1998-01-01

    At a time when political interest in mathematics education is at its highest, this book demonstrates that the issues are far from straightforward. A wide range of international contributors address such questions as: What is mathematics, and what is it for? What skills does mathematics education need to provide as technology advances? What are the implications for teacher education? What can we learn from past attempts to change the mathematics curriculum? Rethinking the Mathematics Curriculum offers stimulating discussions, showing much is to be learnt from the differences in culture, national expectations, and political restraints revealed in the book. This accessible book will be of particular interest to policy makers, curriculum developers, educators, researchers and employers as well as the general reader.

  2. Rethinking the Enlightenment

    Directory of Open Access Journals (Sweden)

    Yehuda Elkana

    2011-11-01

    Full Text Available In this introductory statement, given at the beginning of the Aboagora symposium in Turku in August 2011, Yehuda Elkana highlights the need, in accordance with the title of the conference, to rethink rather than unthink the Enlightenment. Indeed, the Enlightenment remained an unfinished project, but one should never forget that this era formed the basis for the greatest and most important creation of knowledge in all areas for 300 years. Over the last 100 or more years, however, cracks have started to appear in this edifice, Elkana argues: researchers have started to realise that one cannot really distinguish the rational from the irrational and that being contextual does not necessarily mean being relativist.

  3. Rethinking Sexual Citizenship.

    Science.gov (United States)

    Richardson, Diane

    2017-04-01

    Over the last two decades sexuality has emerged as a key theme in debates about citizenship, leading to the development of the concept of sexual citizenship. This article reviews this literature and identifies four main areas of critical framing: work that contests the significance of sexuality to citizenship; critiques that focus on the possibilities and limitations of mobilising the language of citizenship in sexual politics; analyses of sexual citizenship in relation to nationalisms and border making; and literature that critically examines western constructions of sexuality and sexual politics underpinning understandings of sexual citizenship. In order to progress the field theoretically, the article seeks to extend critiques of sexual citizenship focusing on two key aspects of its construction: the sexual citizen-subject and spaces of sexual citizenship. It argues for a critical rethink that encompasses a de-centring of a 'western-centric' focus in order to advance understandings of how sexual citizenship operates both in the Global North and South.

  4. Rethinking macroeconomic policies for development

    Directory of Open Access Journals (Sweden)

    Deepak Nayyar

    2011-09-01

    Full Text Available The global economic crisis has created an opportunity to rethink macroeconomics for development. Such rethinking is both necessary and desirable. It is essential to redefine macroeconomic objectives so that the emphasis is on fostering employment creation and supporting economic growth instead of the focus on price stability alone. It is just as important to rethink macroeconomic policies which cannot simply be used for the management of inflation and the elimination of macroeconomic imbalances, since fiscal and monetary policies are powerful and versatile instruments in the pursuit of development objectives. In doing so, it is essential to the overcome the constraints embedded in orthodox economic thinking and recognize the constraints implicit in the politics of ideology and interests.

  5. Re-thinking residential mobility

    Science.gov (United States)

    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

  6. Rethink Your Drink.

    Science.gov (United States)

    Hartigan, Phyllis; Patton-Ku, Dana; Fidler, Cheri; Boutelle, Kerri N

    2017-03-01

    Sugar-sweetened beverages (SSBs) are linked to obesity; hospitals are a priority setting to reduce intake. This article describes the development, implementation, and results of a focused intervention to reduce SSB sales within a hospital setting. After a formative research process, Rethink Your Drink was launched at a children's hospital in San Diego. The initiative consisted of an educational intervention using the stoplight system to categorize beverages as red, yellow, or green based on sugar content. Beverage sales data were collected for 3 months prior, during the 12-month intervention, and for 4 months after the intervention ended. Monthly red beverage sales decreased from an average of 56% during baseline to 32% at the end of the data collection period (p sales increased from an average of 12.2% during baseline to 38% at the end of the data collection period (p Sales revenue for all drinks remained constant. The intervention resulted in a decrease in SSB sales and an increase in sales of healthier beverage choices. Such interventions can play an important role in obesity prevention and may be more feasible for smaller hospitals with limited resources.

  7. Rethinking language in autism.

    Science.gov (United States)

    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. © The Author(s) 2014.

  8. Rethinking headache chronification.

    Science.gov (United States)

    Turner, Dana P; Smitherman, Todd A; Penzien, Donald B; Lipton, Richard B; Houle, Timothy T

    2013-06-01

    The objective of this series is to examine several threats to the interpretation of headache chronification studies that arise from methodological issues. The study of headache chronification has extensively used longitudinal designs with 2 or more measurement occasions. Unfortunately, application of these designs, when combined with the common practice of extreme score selection as well as the extant challenges in measuring headache frequency rates (eg, unreliability, regression to the mean), induces substantive threats to accurate interpretation of findings. Partitioning the amount of observed variance in rates of chronification and remission attributable to regression artifacts is a critical yet previously overlooked step to learning more about headache as a potentially progressive disease. In this series on rethinking headache chronification, we provide an overview of methodological issues in this area (this paper), highlight the influence of rounding error on estimates of headache frequency (second paper), examine the influence of random error and regression artifacts on estimates of chronification and remission (third paper), and consider future directions for this line of research (fourth paper). © 2013 American Headache Society.

  9. Rethinking Sexual Citizenship

    Science.gov (United States)

    Richardson, Diane

    2016-01-01

    Over the last two decades sexuality has emerged as a key theme in debates about citizenship, leading to the development of the concept of sexual citizenship. This article reviews this literature and identifies four main areas of critical framing: work that contests the significance of sexuality to citizenship; critiques that focus on the possibilities and limitations of mobilising the language of citizenship in sexual politics; analyses of sexual citizenship in relation to nationalisms and border making; and literature that critically examines western constructions of sexuality and sexual politics underpinning understandings of sexual citizenship. In order to progress the field theoretically, the article seeks to extend critiques of sexual citizenship focusing on two key aspects of its construction: the sexual citizen-subject and spaces of sexual citizenship. It argues for a critical rethink that encompasses a de-centring of a ‘western-centric’ focus in order to advance understandings of how sexual citizenship operates both in the Global North and South. PMID:28490816

  10. The Re-Think Tree.

    Science.gov (United States)

    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)

  11. Rethinking Popular Culture and Media

    Science.gov (United States)

    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…

  12. Anachronism in the writing of History: ¿Error or Possibility? Some reflections about the concept of time in Carlo Ginzburg, Marc Bloch and Georges Didi-Huberman

    Directory of Open Access Journals (Sweden)

    Maria Eugenia Chaves Maldonado

    2016-01-01

    Full Text Available In his unfinished and posthumously published book Apologie pour l’histoire, Marc Bloch bestowed on future historians a seminal legacy of critical reflections on the concept of time as the object of historical analysis. During the last decades, the concept of time in History has experienced a renewed interest by professional historians, in particular in reference to the category of anachronism. The Italian historian Carlo Ginzburg and the French art historian Georges Didi-Huberman are among those engaged in this debate. This article offers a reading of two works by these historians with the purpose of underlying the fundamental influence that Marc Bloch’s ideas on time had in Ginzburg and Didi-Hubermans’ critical interventions.

  13. Rethinking Educational Evaluation for Quality Educational Outcomes

    African Journals Online (AJOL)

    Rethinking Educational Evaluation for Quality Educational Outcomes. ... Educational Evaluation (EE) provides information for action by offering invaluable knowledge in terms of theoretical and practical ... AJOL African Journals Online.

  14. Are unions an anachronism?

    Science.gov (United States)

    Schrank, R

    1979-01-01

    The labor movement in the United States has its roots deep in the soil of worker discontent over grueling working conditions, low pay, and indifference of bosses, who profited from others' sweaty labor. As more and more grubby jobs are replaced by technological innovations, as work becomes more abstract and everyone wears a white shirt, and as managers schooled in motivation theory and humane ideals of participation replace the owner-bosses of yesterday, what role will the unions have left to play? The author of this article, who has been in both the labor force and management, explores what the changes in the labor market will be in the future and what these changes will mean for labor-management relations. He does not conclude that there is no role for unions-only that it will be very different and that to survive unions will have to tackle new issues in the workplace. That adaptation will affect management's stance as well.

  15. Rethinking the Space for Religion

    DEFF Research Database (Denmark)

    What happens to people’s sense of belonging when globalization meets with proclaimed regional identities resting heavily on conceptions of religion and ethnicity? Who are the actors stressing cultural heritage and authenticity as tools for self-understanding? In Rethinking the Space for Religion...... as a political and cultural argument. The approach makes a nuanced and fresh survey for researchers and other initiated readers to engage in....

  16. Towards rethinking Project portfolio management

    DEFF Research Database (Denmark)

    Hansen, Lars Kristian; Svejvig, Per

    the last five years. Utilizing the theoretical lens proposed by Svejvig and Andersen (2015), we apply two complementary analytical perspectives to classify and analyze the stocks. One perspective, denoted as classical project management (CPM), highlights key characteristics of conventional research....... A second perspective, denoted as rethinking project management (RPM), highlights characteristics of progressive research. Not surprisingly, characteristics from CPM are very dominant in the stock of most cited publications of all years — instrumentality and controllability in particular. In the newest...

  17. The Danish Agenda for Rethinking Project Management

    DEFF Research Database (Denmark)

    Svejvig, Per; Grex, Sara

    2016-01-01

    Purpose – The purpose of this paper is to analyze the similarities and differences between the Danish Re-thinking Project Management initiative named Project Half Double (PHD) and the rethinking project man-agement (RPM) research stream. The paper furthermore discusses how PHD and RPM can inspire...... ideas and local implementations. Findings – RPM and PHD share a focus on value creation, social processes, learning and complexity while PHD also focuses on lean thinking, agile thinking, front-end loading and leadership, which are largely topics beyond the RPM research stream. Originality...... a foundation for further development of both rethinking project management and Project Half Double....

  18. The Danish Agenda for Rethinking Project Management

    DEFF Research Database (Denmark)

    Svejvig, Per; Grex, Sara

    2016-01-01

    Purpose – The purpose of this paper is to analyze the similarities and differences between the Danish Re-thinking Project Management initiative named Project Half Double (PHD) and the rethinking project man-agement (RPM) research stream. The paper furthermore discusses how PHD and RPM can inspire...... a foundation for further development of both rethinking project management and Project Half Double....... each other in research and practice. Design/methodology/approach – This is an empirical paper based on collaborative research between in-dustry and researchers. PHD has developed principles and practices driven by industry consisting of 10 leading stars and the impact, leadership and flow (ILF) method...

  19. Rethinking Interaction in Creative Work

    DEFF Research Database (Denmark)

    Dalsgaard, Peter

    The use of digital tools has become central in many creative practices. However, research into the design and use of such tools has thus far fallen in between the disciplinary cracks between HCI and Creativity Research. In this position paper, I offer a brief overview of our work on exploring...... and developing digital tools for collaborative creative work that integrates approaches and insights from these two disciplines. On this basis, I offer two theoretical perspectives for discussion at the the Rethinking Interactions workshop: shearing layers, building on studies of architecure in use [Brand 1994...

  20. Rethinking Colour Constancy.

    Science.gov (United States)

    Logvinenko, Alexander D; Funt, Brian; Mirzaei, Hamidreza; Tokunaga, Rumi

    2015-01-01

    Colour constancy needs to be reconsidered in light of the limits imposed by metamer mismatching. Metamer mismatching refers to the fact that two objects reflecting metameric light under one illumination may reflect non-metameric light under a second; so two objects appearing as having the same colour under one illuminant can appear as having different colours under a second. Yet since Helmholtz, object colour has generally been believed to remain relatively constant. The deviations from colour constancy registered in experiments are usually thought to be small enough that they do not contradict the notion of colour constancy. However, it is important to determine how the deviations from colour constancy relate to the limits metamer mismatching imposes on constancy. Hence, we calculated metamer mismatching's effect for the 20 Munsell papers and 8 pairs of illuminants employed in the colour constancy study by Logvinenko and Tokunaga and found it to be so extensive that the two notions-metamer mismatching and colour constancy-must be mutually exclusive. In particular, the notion of colour constancy leads to some paradoxical phenomena such as the possibility of 20 objects having the same colour under chromatic light dispersing into a hue circle of colours under neutral light. Thus, colour constancy refers to a phenomenon, which because of metamer mismatching, simply cannot exist. Moreover, it obscures the really important visual phenomenon; namely, the alteration of object colours induced by illumination change. We show that colour is not an independent, intrinsic attribute of an object, but rather an attribute of an object/light pair, and then define a concept of material colour in terms of equivalence classes of such object/light pairs. We suggest that studying the shift in material colour under a change in illuminant will be more fruitful than pursuing colour constancy's false premise that colour is an intrinsic attribute of an object.

  1. Rethinking Colour Constancy.

    Directory of Open Access Journals (Sweden)

    Alexander D Logvinenko

    Full Text Available Colour constancy needs to be reconsidered in light of the limits imposed by metamer mismatching. Metamer mismatching refers to the fact that two objects reflecting metameric light under one illumination may reflect non-metameric light under a second; so two objects appearing as having the same colour under one illuminant can appear as having different colours under a second. Yet since Helmholtz, object colour has generally been believed to remain relatively constant. The deviations from colour constancy registered in experiments are usually thought to be small enough that they do not contradict the notion of colour constancy. However, it is important to determine how the deviations from colour constancy relate to the limits metamer mismatching imposes on constancy. Hence, we calculated metamer mismatching's effect for the 20 Munsell papers and 8 pairs of illuminants employed in the colour constancy study by Logvinenko and Tokunaga and found it to be so extensive that the two notions-metamer mismatching and colour constancy-must be mutually exclusive. In particular, the notion of colour constancy leads to some paradoxical phenomena such as the possibility of 20 objects having the same colour under chromatic light dispersing into a hue circle of colours under neutral light. Thus, colour constancy refers to a phenomenon, which because of metamer mismatching, simply cannot exist. Moreover, it obscures the really important visual phenomenon; namely, the alteration of object colours induced by illumination change. We show that colour is not an independent, intrinsic attribute of an object, but rather an attribute of an object/light pair, and then define a concept of material colour in terms of equivalence classes of such object/light pairs. We suggest that studying the shift in material colour under a change in illuminant will be more fruitful than pursuing colour constancy's false premise that colour is an intrinsic attribute of an object.

  2. Rethinking mobilities: is tourism dying?

    Directory of Open Access Journals (Sweden)

    Maximiliano Korstanje

    2015-06-01

    Full Text Available The present essay-review explores the conceptual limitations of mobility as an all encompassing theory, which explains why thousand of citizens are unable to make tourism worldwide. Imagining tourism as a massindustry not only rests on a great fallacy but also ignores the effects of last financial crisis in global economies. Only less 1% of total population in the world has the necessary resources to vacation abroad. We need to rethink  mobilities in terms of the great asymmetries caused by capitalism, where behaviour of few  ones is ideologically presented as the guiding values to follow. Like chivalry in Middle Age, mobility and tourism are privileges for global mobile elite alone.

  3. Avenues of Rethinking CSR in development

    DEFF Research Database (Denmark)

    Azizi, Sameer Ahmad

    2015-01-01

    ’. The developmental implication is based on the governance structures triggering CSR in each context. We need to differentiate between strong and weak states and understand the ways that (lack of) states can influence CSR in developing countries. "Responsible business practices" are explored as useful among......The chapter addresses flaws of the CSR literature and seeks to rethink the concept in relation to developing countries. Two avenues for rethinking CSR in developing countries are outlined; a) a governance approach, and b) an application of the term ‘responsible business practices...

  4. Beyond the Spectrum: Rethinking Autism

    Directory of Open Access Journals (Sweden)

    Heather Thomas

    2017-03-01

    Full Text Available The "spectrum" has become the dominant metaphor for conceptualizing autism, with fundamental consequences for notions of disability, diversity, and normality. In this article, we draw on ethnographic research with autistic communities to explore how the notion of the autism spectrum has become a focus of explicit identification, reflection, and contestation. To further this inquiry, we place these debates into conversation with earlier debates regarding another spectrum—the Kinsey Scale, a "spectrum" for conceptualizing sexual orientation that first appeared in 1948 but has been critiqued since the 1970s. How might responses to the Kinsey Scale (like the Klein Grid contribute to rethinking the autism spectrum? This is a question about the cultural and political implications of metaphors and conceptual models. It is of broad importance because the spectrum metaphor is being extended to a range of conditions beyond autism itself. Our goal is thus to build on insights from sexuality studies as well as the insights of autistic persons, advocates, and researchers who wish to forestall the naturalization of "the spectrum." In doing so, we seek to contribute to a discussion of what alternative frameworks might bring to questions of social justice, ability, and human flourishing.

  5. Rethinking reproductive "tourism" as reproductive "exile".

    Science.gov (United States)

    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.

  6. RETHINKING AN AFRICAN ETHICAL SYSTEM: BETWEEN ...

    African Journals Online (AJOL)

    ... paper, to rethink an aspect of African Philosophy Morality (ethics), ancient and modern, among the Tiv of the lower Benue valley in Nigeria. This shall be done in the light of what has changed and what has remained unchanged, and the effects of the change on Tiv social system. (Humanities Review: 2002 2(1): 134-147) ...

  7. Rethink! prototyping transdisciplinary concepts of prototyping

    CERN Document Server

    Nagy, Emilia; Stark, Rainer

    2016-01-01

    In this book, the authors describe the findings derived from interaction and cooperation between scientific actors employing diverse practices. They reflect on distinct prototyping concepts and examine the transformation of development culture in their fusion to hybrid approaches and solutions. The products of tomorrow are going to be multifunctional, interactive systems – and already are to some degree today. Collaboration across multiple disciplines is the only way to grasp their complexity in design concepts. This underscores the importance of reconsidering the prototyping process for the development of these systems, particularly in transdisciplinary research teams. “Rethinking Prototyping – new hybrid concepts for prototyping” was a transdisciplinary project that took up this challenge. The aim of this programmatic rethinking was to come up with a general concept of prototyping by combining innovative prototyping concepts, which had been researched and developed in three sub-projects: “Hybrid P...

  8. Rethinking Disarmament, Demobilization and Reintegration Programs

    Directory of Open Access Journals (Sweden)

    Jairo Munive

    2015-10-01

    Full Text Available This article introduces the special issue on DDR and ‘Armed Non-Statutory Actors’ (ANSAs which we prefer to the less precise label of Armed Non-State Actors. The understanding that disarmament, demobilization and reintegration (DDR programs are essential in helping to prevent the recurrence of war in post-conflict situations is at the heart of current peacebuilding practice and the academic literature on peacekeeping and stabilization. But the changing strategic context of DDR programs and in particular the proliferation of ANSAs presents new challenges, the responses to which have been characterized as ‘second generation’ DDR. The changing context poses new questions and forces us to rethink assumptions and templates of DDR as the concept is blurred and expanded. The question is if it makes sense to hold on to the concept or whether the assumptions associated with it will get in the way of rethinking templates for violence reduction in the future.

  9. Rethinking Information Systems in the Public Sector

    DEFF Research Database (Denmark)

    Medaglia, Rony

    2014-01-01

    This section of Information Polity consists of papers presented during the workshop “Rethinking Information Systems in the Public Sector: Bridging Academia and Public Service”. The workshop was held on 8 June 2014 in Tel Aviv, Israel, in conjunction with the European Conference on Information...... Systems (ECIS 2014), and it is part of the activities of the Special Interest Group for eGovernment (SIGeGov) of the Association for Information Systems (AIS)....

  10. Gap analysis: rethinking the conceptual foundations

    OpenAIRE

    Langford, Gary O.; Franck, Raymond; Huynh, Tom; Lewis, Ira A.

    2007-01-01

    Acquisition research (Graduate School of Business & Public Policy) Gap Analysis is widely regarded as a useful tool to facilitate commercial and defense system acquisitions. This paper is a rethinking of the theoretical foundations and systematics of Gap Analysis with practical extensions to illustrate its utility and limitations. It also provides a new perspective on those theoretical foundations from the perspectives of systems and value engineering. The growing sophistication and comple...

  11. Hydrodynamic disperser

    Energy Technology Data Exchange (ETDEWEB)

    Bulatov, A.I.; Chernov, V.S.; Prokopov, L.I.; Proselkov, Yu.M.; Tikhonov, Yu.P.

    1980-01-15

    A hydrodynamic disperser is suggested which contains a housing, slit nozzles installed on a circular base arranged opposite from each other, resonators secured opposite the nozzle and outlet sleeve. In order to improve the effectiveness of dispersion by throttling the flow, each resonator is made in the form of a crimped plate with crimpings that decrease in height in a direction towards the nozzle.

  12. Dispersion Forces

    CERN Document Server

    Buhmann, Stefan Yoshi

    2012-01-01

    In this book, a modern unified theory of dispersion forces on atoms and bodies is presented which covers a broad range of advanced aspects and scenarios. Macroscopic quantum electrodynamics is shown to provide a powerful framework for dispersion forces which allows for discussing general properties like their non-additivity and the relation between microscopic and macroscopic interactions. It is demonstrated how the general results can be used to obtain dispersion forces on atoms in the presence of bodies of various shapes and materials. Starting with a brief recapitulation of volume I, this volume II deals especially with bodies of irregular shapes, universal scaling laws, dynamical forces on excited atoms, enhanced forces in cavity quantum electrodynamics, non-equilibrium forces in thermal environments and quantum friction. The book gives both the specialist and those new to the field a thorough overview over recent results in the field. It provides a toolbox for studying dispersion forces in various contex...

  13. Rethinking Research for Genetically Modified (GM) Food

    OpenAIRE

    Yin-Ling; Lin

    2012-01-01

    This paper suggests a rethinking of the existing research about Genetically Modified (GM) food. Since the first batch of GM food was commercialised in the UK market, GM food rapidly received and lost media attention in the UK. Disagreement on GM food policy between the US and the EU has also drawn scholarly attention to this issue. Much research has been carried out intending to understand people-s views about GM food and the shaping of these views. This paper was based o...

  14. Rethinking the economics of climate change

    International Nuclear Information System (INIS)

    Damian, Michel

    2012-05-01

    The paper makes a case for rethinking the economics of climate change. It questions the way the problem was conventionally framed and solved through top-down international cooperation and carbon emission permits, taxes and pricing. The paper argues that the on-going industrial and energy transition reflects a paradigmatic shift as compared to neoclassical environmental economics that has framed climate policy since the Rio conference in 1992. On a normative basis, the paper maintains that a carbon tax should not follow a Pigovian rationale. To be feasible such a tax should be of a Marshallian nature, i.e. earmarked, and rather modest at the beginning. (author)

  15. Rethinking resistance : revolt and violence in African history

    NARCIS (Netherlands)

    Abbink, G.J.; Bruijn, de M.E.; Walraven, van K.

    2003-01-01

    This collective volume reinterprets the genre of resistance studies, introduces recent conceptual perspectives and considers examples of African (civil) wars and insurgent movements. Contributions: Rethinking resistance in African history, an introduction, by Klaas van Walraven and Jon Abbink. Part

  16. Rethinking Game Based Learning: applying pedagogical standards to educational games

    NARCIS (Netherlands)

    Schmitz, Birgit; Kelle, Sebastian

    2010-01-01

    Schmitz, B., & Kelle, S. (2010, 1-6 February). Rethinking Game Based Learning: applying pedagogical standards to educational games. Presentation at JTEL Winter School 2010 on Advanced Learning Technologies, Innsbruck, Austria.

  17. Re-thinking instructional strategies for enhancing gender equity in ...

    African Journals Online (AJOL)

    Re-thinking instructional strategies for enhancing gender equity in learning ... instructional mode on the cognitive achievement of boys and girls in primary science. ... Results revealed no statistically significant difference in the achievement of ...

  18. Book Review: J. Kelly. Rethinking Industrial Relations: Mobilization ...

    African Journals Online (AJOL)

    Book Review: J. Kelly. Rethinking Industrial Relations: Mobilization, Collectivism and Long Waves. K. Moody. Workers in a Lean World: Unions in the International Economy. B. Nissen. Which Direction for Organized Labour? Essays on Organizing, Outreach and Internal Transformation.

  19. Rethinking Volks V Robinson: The Implications of Applying a ...

    African Journals Online (AJOL)

    Rethinking Volks V Robinson: The Implications of Applying a "Contextaulised Choice Model" to Prospective South African Domestic Partnerships Legislation. ... is enacted. Keywords: Life partnership; domestic partnership; Domestic Partnerships Bill; choice argument; contextualised choice model; reciprocal duty of support.

  20. Ethnic diversity and knowledge synergies: Rethinking the interrelations

    DEFF Research Database (Denmark)

    Lauring, Jakob

    2005-01-01

    desire to see ethnical diversity as productive. Theoretical reviews and empirical research have indicated that the link between diversity and knowledge synergy cannot be taken for granted. This article argues that some theoretical rethinking of managerial strategies toward cultural diversity...

  1. Rethinking I-94: Minnesota DOT: A TPCB Peer Exchange

    Science.gov (United States)

    2017-12-01

    This report highlights key recommendations and noteworthy practices identified at Rethinking I-94: MnDOT Peer Exchange held on August 15-16, 2017 in St. Paul, Minnesota. This event was sponsored by the Transportation Planning Capacity Building ...

  2. Chemical dispersants

    NARCIS (Netherlands)

    Rahsepar, Shokouhalsadat; Smit, Martijn P.J.; Murk, Albertinka J.; Rijnaarts, Huub H.M.; Langenhoff, Alette A.M.

    2016-01-01

    Chemical dispersants were used in response to the Deepwater Horizon oil spill in the Gulf of Mexico, both at the sea surface and the wellhead. Their effect on oil biodegradation is unclear, as studies showed both inhibition and enhancement. This study addresses the effect of Corexit on oil

  3. Rethinking Value in the Bio-economy

    Science.gov (United States)

    2016-01-01

    Current debates in science and technology studies emphasize that the bio-economy—or, the articulation of capitalism and biotechnology—is built on notions of commodity production, commodification, and materiality, emphasizing that it is possible to derive value from body parts, molecular and cellular tissues, biological processes, and so on. What is missing from these perspectives, however, is consideration of the political-economic actors, knowledges, and practices involved in the creation and management of value. As part of a rethinking of value in the bio-economy, this article analyzes three key political-economic processes: financialization, capitalization, and assetization. In doing so, it argues that value is managed as part of a series of valuation practices, it is not inherent in biological materialities. PMID:28458406

  4. Rethinking Participation and Re-enacting Its Dilemmas?

    DEFF Research Database (Denmark)

    Eriksson, Birgit; Stephensen, Jan Løhmann

    2015-01-01

    In 2012 the Danish city of Aarhus was appointed European Capital of Culture for 2017. The appointment was based on an ambitious programme that – under the headline Rethink – tried to set an agenda of societal transformation, mainly by seeking to increase the impact of art and culture, and to enha......In 2012 the Danish city of Aarhus was appointed European Capital of Culture for 2017. The appointment was based on an ambitious programme that – under the headline Rethink – tried to set an agenda of societal transformation, mainly by seeking to increase the impact of art and culture...... Rethink project. Informed by theoretical distinctions between different forms of participation, and the diverse interests invested in participatory processes, we investigate how the young cultural entrepreneurs and the artistic administrators of Aarhus 2017 separately, in conjunction, and sometimes even...

  5. Dispersion strengthening

    International Nuclear Information System (INIS)

    Scattergood, R.O.; Das, E.S.P.

    1976-01-01

    Using digital computer-based methods, models for dispersion strengthening can now be developed which take into account many of the important effects that have been neglected in the past. In particular, the self interaction of a dislocation can be treated, and a computer simulation method was developed to determine the flow stress of a random distribution of circular, impenetrable obstacles, taking into account all such interactions. The flow stress values depended on the obstacle sizes and spacings, over and above the usual 1/L dependence where L is the average obstacle spacing. From an analysis of the results, it was found that the main effects of the self interactions can be captured in a line tension analogue in which the obstacles appear to be penetrable

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

    Science.gov (United States)

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

    2016-03-06

    The 5G network is anticipated to meet the challenging requirements of mobile traffic in the 2020s, which are characterized by super high data rate, low latency, high mobility, high energy efficiency and high traffic density. This paper provides an overview of China Mobile's 5G vision and potential solutions. Three key characteristics of 5G are analysed, i.e. super fast, soft and green. The main 5G R&D themes are further elaborated, which include five fundamental rethinkings of the traditional design methodologies. The 5G network design considerations are also discussed, with cloud radio access network, ultra-dense network, software defined network and network function virtualization examined as key potential solutions towards a green and soft 5G network. The paradigm shift to user-centric network operation from the traditional cell-centric operation is also investigated, where the decoupled downlink and uplink, control and data, and adaptive multiple connections provide sufficient means to achieve a user-centric 5G network with 'no more cells'. The software defined air interface is investigated under a uniform framework and can adaptively adapt the parameters to well satisfy various requirements in different 5G scenarios. © 2016 The Author(s).

  7. Basic Concepts for rethinking environmental issues

    International Nuclear Information System (INIS)

    Gonzalez Ladron de Guevara, Francisco Jose; Valencia Cuellar, Jorge

    2013-01-01

    This article presents a review of the fundamental concepts from which environmental problems have been explained and solved during the last decades. Environment is understood as an encounter between nature and culture that is a social construct that reflects the interaction between human beings and the biophysical space in which they live. On the other hand, development is conceived as the ability that societies have to develop their potentialities, being a notion of a totalizing and ethical political nature, which incorporates the biophysical and social heritage of a certain society. Regarding the concept of culture, it must be said that it is built upon the basis that this is an adaptive strategy of the human species. Finally, the relationships between the concepts of culture, environment and development are studied in order to formulate a new perspective for rethinking the environmental issue, so that, in turn, it could be used to redirect survival strategies that human beings currently apply in their interaction with the environment.

  8. Rethinking tourism: Bali’s failure

    Science.gov (United States)

    Khamdevi, M.; Bott, H.

    2018-03-01

    Bali is famous as the tourist destination in the world. Ironically, most of the people of Bali thought that tourism in Bali is a failure. The negative impact showed on modernization in South Bali, including Denpasar, Kuta, and Ubud. Cultural imperialism has shifted local culture in many aspects, especially the traditional houses and buildings. The climax of this problem is the development of Benoa Bay Reclamation, where the sacred location for the traditional ceremony will be built for new tourism development that offers pleasure and leisure. This raised hard protest from the people of Bali. They are also afraid that the Balinese cultural and natural environment will vanish. On the other hand, some movement of sustainable tourism in North Bali, that ran by the local community has also arisen. What is tourism? Is it only for pleasure and leisure only? This research will discuss the rethinking of tourism definition with Bali as a reflection case. The purpose of this paper is to find its right definition with qualitative methodology. A more sustainable tourism that more on local context would be a research result.

  9. Hydrodynamic dispersion

    International Nuclear Information System (INIS)

    Pryce, M.H.L.

    1985-01-01

    A dominant mechanism contributing to hydrodynamic dispersion in fluid flow through rocks is variation of travel speeds within the channels carrying the fluid, whether these be interstices between grains, in granular rocks, or cracks in fractured crystalline rocks. The complex interconnections of the channels ensure a mixing of those parts of the fluid which travel more slowly and those which travel faster. On a macroscopic scale this can be treated statistically in terms of the distribution of times taken by a particle of fluid to move from one surface of constant hydraulic potential to another, lower, potential. The distributions in the individual channels are such that very long travel times make a very important contribution. Indeed, while the mean travel time is related to distance by a well-defined transport speed, the mean square is effectively infinite. This results in an asymmetrical plume which differs markedly from a gaussian shape. The distribution of microscopic travel times is related to the distribution of apertures in the interstices, or in the microcracks, which in turn are affected in a complex way by the stresses acting on the rock matrix

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

    Science.gov (United States)

    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,…

  11. Re-thinking clinical research training in residency

    Directory of Open Access Journals (Sweden)

    Jennifer O'Brien

    2014-12-01

    Conclusions: We conclude that medical educators should critically re-think our programs to develop resident researchers. If it is worthwhile to require original research projects during residency, then we must consider the priorities of local settings to best serve the public interest.

  12. The African Mind and Globalization: Rethinking the Causes of ...

    African Journals Online (AJOL)

    The African Mind and Globalization: Rethinking the Causes of Africa's ... which has become “the new bride” in building socio-economic, socio-cultural and ... Africa, the once touted “cradle of civilisation”, and indeed, the forerunner of science ...

  13. Academic and Career Development: Rethinking Advising for Asian American Students

    Science.gov (United States)

    Kodama, Corinne M.; Huynh, Jill

    2017-01-01

    Academic and career development for Asian American students is complicated by cultural influences, interdependence with family, and racial stereotyping. This chapter highlights research, theory, and practice to help educators rethink traditional advising approaches to more appropriately work with Asian American students as they navigate their…

  14. Intimate Distance: Rethinking the Unthought God in Christianity

    NARCIS (Netherlands)

    Kate, L. ten

    2008-01-01

    The work of the French philosopher Jean-Luc Nancy shares with the thinkers of the ‘theological turn in phenomenology’ the programmatic desire to place the ‘theological’, in the broad sense of rethinking the religious traditions in our secular time, back on the agenda of critical thought. Like those

  15. Objectivity and Subjectivity: an Argument for Rethinking the ...

    African Journals Online (AJOL)

    Objectivity and Subjectivity: an Argument for Rethinking the Philosophy Syllabus. ... South African Journal of Philosophy ... The aftermath of the rise of modern physics has been a picture of reality as alienated from our commonly experienced sense of purposes, aims, and intentions as defining our everyday lives, what we ...

  16. La invención de la familia: supervivencia, anacronismo y ficción en la fotografía familiar del primer franquismo = Invention of family: survival, anachronism and fiction in family photography during Francoism

    Directory of Open Access Journals (Sweden)

    Mónica Alonso Riveiro

    2015-01-01

    Full Text Available A mediados del siglo XX la fotografía familiar se había popularizado en Europa. Ello produjo una modernización en los códigos de representación; se fotografía con más espontaneidad, los retratos pierden su carácter idealizado y solemne y, paulatinamente, desparece también el carácter ritual del acto fotográfico. En cambio, en la España del primer franquismo la fotografía familiar muestra una pervivencia de antiguos usos, técnicas y estéticas. Se mantienen valores anacrónicos (carácter ritual, confianza en su carácter probatorio y consideración como objeto de culto que remiten a la concepción decimonónica del medio.El presente estudio pretende, a partir de fotografías familiares españolas de esta época, identificar y describir estos anacronismos. También explicar cómo estos valores llevaron a los españoles a considerar la fotografía como el medio ideal para representar y (reconstruir la unidad de la familia, quebrada tras la guerra por el exilio o la muerte. In the middle of the 20th, family photography has been popular in Europe. This popularization led to a change in the codes of representation; the photos become more spontaneous, portraits lose their idealization and the act of shooting, gradually, lose their cult conception. In contrast, in Spain during the first years of Franco regime, family photography shows the survival of ancient practices, techniques  and aesthetics. Some anachronistic values that refer to the nineteenth-century conception of the medium, (ritual character, confidence in his probative value and the consideration as an cult item survives in photography.This paper demonstrates these anachronisms with a collection of family photographs from this period. Also explain how these values led the Spaniards to consider photography as the ideal for representing and (rebuild the unity of the family, broken after the war by exile or death.

  17. Seed dispersal in fens

    NARCIS (Netherlands)

    Middleton, Beth; van Diggelen, Rudy; Jensen, Kai

    Question: How does seed dispersal reduce fen isolation and contribute to biodiversity? Location: European and North American fens. Methods: This paper reviews the literature on seed dispersal to fens. Results: Landscape fragmentation may reduce dispersal opportunities thereby isolating fens and

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

    Science.gov (United States)

    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.

  19. Towards Enhanced Affective Design: Rethinking the Notion of Design

    Science.gov (United States)

    Kim, SuKyoung; Cho, Youngil

    2017-09-01

    Design disciplines have been contributing to shaping the life of human beings, as well as fostering culture and heritage. Design disciplines and research have been rapidly transforming, and not only objects but also services are target of design. This paper reviews design disciplines towards enhanced affective design, which attributes to intuitive knowledge. It aims at rethinking the notion of design to propose a conceptual framework for integrating user experience into objects that strengthen the form and function based design with pleasing.

  20. Rethinking the Method of Principled Negotiation--1981-2011

    OpenAIRE

    Yoshiaki Nomura

    2012-01-01

    Fisher, Ury & Patton's Getting to Yes has established the Seven Elements of Negotiation and shows what a "theory for practitioners" should be. However, the following three points, among others, should be given reconsideration. First, though various authors support the framework of the seven elements, their interrelationship has not been clarified by those authors. Second, the meaning of 5 core concerns and its relationship with the element of interests are not so clear. Rethinking of non-econ...

  1. Rethinking Socialization Research through the Lens of New Materialism

    OpenAIRE

    Höppner, Grit

    2017-01-01

    In recent decades, socialization research appears to have suffered the loss of its former capacity to explain the processes of becoming a socialized subject in a social environment. In this article, I review socialization theories taking into account assumptions regarding human subjects and their social environments. I confront them with the idea of rethinking dualisms, ontologies, and agencies addressed by the field of new materialism. I propose a new materialist-inspired socialization theor...

  2. Reversing functional extinction of mammals prompts a rethink of paradigms about seed fate in arid Australia.

    Science.gov (United States)

    Mills, Charlotte H; Letnic, Mike

    2018-01-01

    Functional extinction of once abundant species has frequently preceded understanding of their ecological roles. Consequently, our understanding of ecosystems is prone to shifting baselines because it often relies on observations made on depauperate species assemblages. In Australian deserts, current paradigms are that ants are the dominant granivores, mammals are unimportant seed predators and that myrmecochory in many Australian shrubs is an adaptation to increase dispersal distance and direct seeds to favourable germination sites. Here, we ask whether these paradigms could be artefacts of mammal extinction. We take advantage of a predator-proof reserve within which locally extinct native mammals have been reintroduced to compare seed removal by ants and mammals. Using foraging trays that selectively excluded mammals and ants we show that a reintroduced mammal, the woylie ( Bettongia penicillata ) was at least as important as ants in the removal of seeds of two shrub species ( Dodonaea viscosa and Acacia ligulata ). Our results provide evidence that the dominance of ants as granivores and current understanding of the adaptive benefit of myrmecochory in arid Australia may be artefacts of the functional extinction of mammals. Our study shows how reversing functional extinction can provide the opportunity to rethink contemporary understanding of ecological processes.

  3. The File System Interface is an Anachronism

    OpenAIRE

    Ellard, Daniel

    2003-01-01

    Contemporary file systems implement a set of abstractions and semantics that are suboptimal for many (if not most) purposes. The philosophy of using the simple mechanisms of the file system as the basis for a vast array of higher-level mechanisms leads to inefficient and incorrect implementations. We propose several extensions to the canonical file system model, including explicit support for lock files, indexed files, and resource forks, and the benefit of session semantics for write updates...

  4. Clock synchronization and dispersion

    International Nuclear Information System (INIS)

    Giovannetti, Vittorio; Lloyd, Seth; Maccone, Lorenzo; Wong, Franco N C

    2002-01-01

    We present a method to defeat effects of dispersion of timing signals when synchronizing clocks. It is based on the recently proposed 'conveyor belt synchronization' scheme and on the quantum dispersion cancellation effect

  5. Dispersing powders in liquids

    CERN Document Server

    Nelson, RD

    1988-01-01

    This book provides powder technologists with laboratory procedures for selecting dispersing agents and preparing stable dispersions that can then be used in particle size characterization instruments. Its broader goal is to introduce industrial chemists and engineers to the phenomena, terminology, physical principles, and chemical considerations involved in preparing and handling dispersions on a commercial scale. The book introduces novices to: - industrial problems due to improper degree of dispersion; - the nomenclature used in describing particles; - the basic physica

  6. Theory of dispersive microlenses

    Science.gov (United States)

    Herman, B.; Gal, George

    1993-01-01

    A dispersive microlens is a miniature optical element which simultaneously focuses and disperses light. Arrays of dispersive mircolenses have potential applications in multicolor focal planes. They have a 100 percent optical fill factor and can focus light down to detectors of diffraction spot size, freeing up areas on the focal plane for on-chip analog signal processing. Use of dispersive microlenses allows inband color separation within a pixel and perfect scene registration. A dual-color separation has the potential for temperature discrimination. We discuss the design of dispersive microlenses and present sample results for efficient designs.

  7. Rethinking Hearing Aid Fitting by Learning From Behavioral Patterns

    DEFF Research Database (Denmark)

    Johansen, Benjamin; Petersen, Michael Kai; Pontoppidan, Niels Henrik

    2017-01-01

    users to remotely enhance auditory focus and attenuate background noise to improve speech intelligibility. N=5, participants changed program settings and adjusted volume on their hearing instruments using their smartphones. We found that individual behavioral patterns affected the usage of the devices....... A significant difference between program usage, and weekdays versus weekends, were found. Users not only changed programs to modify aspects of directionality and noise reduction, but also continuously adjusted the volume. Rethinking hearing instruments as devices that adaptively learn behavioral patterns based...

  8. Rethinking Faraday's law for teaching motional electromotive force

    International Nuclear Information System (INIS)

    Zuza, Kristina; Guisasola, Jenaro; Michelini, Marisa; Santi, Lorenzo

    2012-01-01

    This study shows physicists' discussions on the meaning of Faraday's law where situations involving extended conductors or moving contact points are particularly troublesome. We raise questions to test students' difficulties in applying Faraday's law in motional electromotive force phenomena. We suggest the benefit of analysing these phenomena when teaching Faraday's law in introductory physics courses at university. We are not implying that Faraday's law should be revised, but we do want to set the stage for careful rethinking regarding the meaning and application of each term of the law as it appears in traditional introductory courses. (paper)

  9. [Towards a theoretical framework for rethinking cultural accessibility].

    Science.gov (United States)

    Landini, Fernando; Cowes, Valeria González; D'Amore, Eliana

    2014-02-01

    Health services accessibility is a key health policy issue. However, few in-depth studies have addressed it theoretically. Most distinguish between availability, accessibility, and acceptability, or between geographic, financial, administrative, and cultural accessibility. We discuss and analyze the concept of accessibility as conflictive articulation between supply and demand in health. The article addresses the importance of cultural accessibility, rethinking it as a social interface, i.e., a social arena with clashing worldviews (namely, those of physicians and patients). The approach sheds light on the complex processes of grasping, translating, and reshaping knowledge and recommendations within such interaction.

  10. Rethinking learning networks collaborative possibilities for a Deleuzian century

    CERN Document Server

    Kamp, Annelies

    2013-01-01

    In the face of today's complex policy challenges, various forms of 'joining-up' - networking, collaborating, partnering - have become key responses. However, institutions often fail to take advantage of the full benefits that joining-up offers. In this book, the author draws on ethnographic research into learning networks in post compulsory education and training in the state of Victoria, Australia, to explore why this might be the case and presents an argument for rethinking how joining-up works in practice. Throughout the book, Deleuzian concepts are engaged to forge a 'little complicating m

  11. RETHINKING THE GOVERNANCE OF SECURITY: THE PROBLEM OF UNCONSCIOUS CONSEQUENCES

    Directory of Open Access Journals (Sweden)

    CARLOS SOLAR FORNAZZARI

    2017-12-01

    Full Text Available Friesendorf and Daase, both researchers from the Peace Reasearch Institute Frankfurt (PRIF, establish in Rethinking Security Governance the problem of unforeseen consequences that are the result of the implementation of almost any security policy. The results of this book confirm that many, but not all, consequences are problematic, due in part to the fact that the effects of a security policy have become contingent on an infinity of factors that make it highly complex to attribute to what extent success was due or the failure of a particular policy.

  12. Rethinking communication in innovation processes: creating space for change in complex systems

    NARCIS (Netherlands)

    Leeuwis, C.; Aarts, N.

    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

  13. Rethinking Communication in Innovation Processes: Creating Space for Change in Complex Systems

    NARCIS (Netherlands)

    Leeuwis, C.; Aarts, N.

    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

  14. Rethinking Study and Management of Agricultural Systems for Policy Design

    Directory of Open Access Journals (Sweden)

    Johann Baumgärtner

    2013-09-01

    Full Text Available There is a concern that agriculture will no longer be able to meet, on a global scale, the growing demand for food. Facing such a challenge requires new patterns of thinking in the context of complexity and sustainability sciences. This paper, focused on the social dimension of the study and management of agricultural systems, suggests that rethinking the study of agricultural systems entails analyzing them as complex socio-ecological systems, as well as considering the differing thinking patterns of diverse stakeholders. The intersubjective nature of knowledge, as studied by different philosophical schools, needs to be better integrated into the study and management of agricultural systems than it is done so far, forcing us to accept that there are no simplistic solutions, and to seek a better understanding of the social dimension of agriculture. Different agriculture related problems require different policy and institutional approaches. Finally, the intersubjective nature of knowledge asks for the visualization of different framings and the power relations taking place in the decision-making process. Rethinking management of agricultural systems implies that policy making should be shaped by different principles: learning, flexibility, adaptation, scale-matching, participation, diversity enhancement and precaution hold the promise to significantly improve current standard management procedures.

  15. Introduction to "Rethinking Business History in Modern China"

    Directory of Open Access Journals (Sweden)

    Wen-hsin Yeh

    2015-09-01

    Full Text Available In this special issue of Cross-Currents, the contributing authors look at how business linked China and the world from the mid-nineteenth to the mid-twentieth century, and how Chinese and foreign companies interacted with one another, as well as with political power, long before today. Some authors concentrate on material connections, including shipping, banking, the building of railroads, the spread of the motion picture industry, international treaties, and the formation of knowledge, while others investigate the role of business culture and how entrepreneurship and networks of trust crossed borders. Both of these aspects are set against the backdrop of simultaneous Chinese state-building efforts that became evident in the state creation of a national market and the formation of political borders. All of the authors collected here draw on case studies of individual entrepreneurs or companies, just as they draw on the new historical and theoretical scholarship summarized above to fill out the picture of China’s economic development within global processes. As the contributions to this issue demonstrate, rethinking Chinese business history also forces us to rethink Chinese urban history more generally... The new pictures of business practice presented here entail a remapping of the spatial dynamics of such activities and thereby a new understanding of the making of urban China...

  16. Book Review: Jessica F Green, Rethinking Private Authority: Agents and Entrepreneurs in Global Environmental Governance

    DEFF Research Database (Denmark)

    Keremis, Anestis

    2017-01-01

    Book review of "Rethinking Private Authority: Agents and Entrepreneurs in Global Environmental Governance" by Jessica F Green. Princeton,NJ and Oxford: Princeton University Press, 2014.215 pp., £16.95 (p/b), ISBN 9780691157597......Book review of "Rethinking Private Authority: Agents and Entrepreneurs in Global Environmental Governance" by Jessica F Green. Princeton,NJ and Oxford: Princeton University Press, 2014.215 pp., £16.95 (p/b), ISBN 9780691157597...

  17. Dispersal of forest insects

    Science.gov (United States)

    Mcmanus, M. L.

    1979-01-01

    Dispersal flights of selected species of forest insects which are associated with periodic outbreaks of pests that occur over large contiguous forested areas are discussed. Gypsy moths, spruce budworms, and forest tent caterpillars were studied for their massive migrations in forested areas. Results indicate that large dispersals into forested areas are due to the females, except in the case of the gypsy moth.

  18. Improved new generation dispersants

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    The use of dispersants to combat oil spills has attracted controversy over the years, and there has been a number of accusations of the chemicals involved doing more harm than good. A new study by the International Petroleum Industry Environmental Conservation Association discusses the positive and the negatives of dispersant use to be considered when drawing up spill contingency plans. (author)

  19. Seed dispersal in fens

    Science.gov (United States)

    Middleton, B.; Van Diggelen, R.; Jensen, K.

    2006-01-01

    Question: How does seed dispersal reduce fen isolation and contribute to biodiversity? Location: European and North American fens. Methods: This paper reviews the literature on seed dispersal to fens. Results: Landscape fragmentation may reduce dispersal opportunities thereby isolating fens and reducing genetic exchange. Species in fragmented wetlands may have lower reproductive success, which can lead to biodiversity loss. While fens may have always been relatively isolated from each other, they have become increasingly fragmented in modern times within agricultural and urban landscapes in both Europe and North America. Dispersal by water, animals and wind has been hampered by changes related to development in landscapes surrounding fens. Because the seeds of certain species are long-lived in the seed bank, frequent episodes of dispersal are not always necessary to maintain the biodiversity of fens. However, of particular concern to restoration is that some dominant species, such as the tussock sedge Carex stricta, may not disperse readily between fens. Conclusions: Knowledge of seed dispersal can be used to maintain and restore the biodiversity of fens in fragmented landscapes. Given that development has fragmented landscapes and that this situation is not likely to change, the dispersal of seeds might be enhanced by moving hay or cattle from fens to damaged sites, or by reestablishing lost hydrological connections. ?? IAVS; Opulus Press.

  20. Dispersal and metapopulation stability

    Directory of Open Access Journals (Sweden)

    Shaopeng Wang

    2015-10-01

    Full Text Available Metapopulation dynamics are jointly regulated by local and spatial factors. These factors may affect the dynamics of local populations and of the entire metapopulation differently. Previous studies have shown that dispersal can stabilize local populations; however, as dispersal also tends to increase spatial synchrony, its net effect on metapopulation stability has been controversial. Here we present a simple metapopulation model to study how dispersal, in interaction with other spatial and local processes, affects the temporal variability of metapopulations in a stochastic environment. Our results show that in homogeneous metapopulations, the local stabilizing and spatial synchronizing effects of dispersal cancel each other out, such that dispersal has no effect on metapopulation variability. This result is robust to moderate heterogeneities in local and spatial parameters. When local and spatial dynamics exhibit high heterogeneities, however, dispersal can either stabilize or destabilize metapopulation dynamics through various mechanisms. Our findings have important theoretical and practical implications. We show that dispersal functions as a form of spatial intraspecific mutualism in metapopulation dynamics and that its effect on metapopulation stability is opposite to that of interspecific competition on local community stability. Our results also suggest that conservation corridors should be designed with appreciation of spatial heterogeneities in population dynamics in order to maximize metapopulation stability.

  1. New challenges to rethink the training of ecuadorian teachers

    Directory of Open Access Journals (Sweden)

    María Sol Villagómez

    2012-12-01

    Full Text Available Training ecuadorian teachers has traditionally been linked to public policy and national curricula that have defined the task of teaching, classroom work, and what basic teacher training institutions should prioritize on when it comes to training teachers. Recent years have seen major changes in the educational sector, as well as a revaluation of the teaching trade. New training challenges arise, not only from the teacher's perspective as executor of the curricula, but as a key player in the educational process. We need to rethink the training of teachers to and from a critical reflection and research point-of-view, in order to reflect on the curricula, their own experience, and their relevance in relation to the framework in wich they develop.

  2. Review Essay: Rethinking Gender Justice a Transnational Approach

    DEFF Research Database (Denmark)

    Siim, Birte

    2015-01-01

    Ambivalence” is one reason for feminists to be concerned about Fraser’s new theoretical and political approach. Here Fraser uses Karl Polanyi’s classical book: ’The Great Transformation’ (1944) as inspiration to rethink the character of the present political-economic crisis, social justice...... and the emancipatory potentials of feminism. The ambitious aim of the book is to contribute to feminism’s theoretical and political project in a globalized world. The title:’Fortunes of Feminism’, the prologue and the book’s structure as a drama in three acts all refer to Fraser’s interpretation of the evolution...... in in Justice Interruptus; two articles have only appeared in French It is therefore great to have a collection of some of her best articles, but the question is what gender researchers can learn from this book? To me, the final chapter: ”Between Marketization and Social Protection: Resolving the Feminist...

  3. Rethinking cities in the post-carbon society. Research notebook

    International Nuclear Information System (INIS)

    Cecutti-Etahiri, Nathalie; Brou, Evane; Riviere, Antoine; Emelianoff, C.; Mor, E.; Chevalier, J.; Boulianne, L.M.; Tabaka, K.; Pichavant, F.; Barbezet, S.; Pezet-Kuhn, M.; Aubree, L.; Bonduelle, A.; Metivier, S.; Dossier, J.; Hain, L.; Pares-Ramos, I.K.; Dupas, S.; Coutard, O.; Rutherford, J.; Gillet, C.; Lange, J.; Ranoux, M.; Noisette, P.; Deseez, G.; Allio, C.; Waisman, H.; Mousel, Michel; Girard, S.; Huber, A.; Thomas, Y.; Dobre, M.; Cordellier, M.; Barbier, C.; Blanc, N.; Sander, A.; Castelain Meunier, C.; Joliton, D.; Leroy, P.; Pour Rou Chottamin, N.; Radanne, P.; Chevrier, S.; Darris, G.; Gauthier, V.; Theile, D.; Souami, T.; Kasdi, I.; Meyer, P.; Artous, A.; Salini, P.; Vanel, S.

    2014-10-01

    This document compiles the different syntheses of the research projects which were used to prepare the synthesis report 'Rethinking cities in the post-carbon society', published in March 2014 by the French Agency of environment and energy mastery (Ademe). It allows to browse more precisely the experience of six French cities (Lille, Mulhouse, Tours, Fontainebleau, Plaine Commune et Grenoble) and to go deeper into the governance stakes. This publication also brings together some unpublished sectoral studies about life styles and consumption habits, energy inequalities and poverty, housing etc. Different levels of reading of the document are possible, in order to make it accessible to all readers and to involve all citizens in the post-carbon city culture

  4. Creative learning technologies as a catalyst for rethinking education

    DEFF Research Database (Denmark)

    Gjedde, Lisa

    2017-01-01

    is on exploring how learning with creative technologies can be a catalyst for rethinking education in primary and lower secondary school The mixed methods based research project has involved classes from all schools in one municipality in Denmark in digital creative lab activities The research points...... presents preliminary results from an R&D project on teacher led designs for creative and multimodal learning The focus is on developing designs for learning using creative learning technologies These include digital storytelling with mobile devices and digital animation in hybrid environments The focus......There is a movement towards a new paradigm in the mediatized Scandinavian societies that aims at developing the students' creativity, critical sense and ability to collaborate and communicate, thereby equipping them with necessary media skills and competencies for 21st Century learning This paper...

  5. Climate Change after the International : Rethinking Security, Territory and Authority

    International Nuclear Information System (INIS)

    Stripple, Johannes

    2005-01-01

    What does a politics after the international mean? Many strands of contemporary scholarship converge on the image of the international as obsolete, but strongly diverge on the contours of the kinds of politics that are superseding it. The modern state has been pivotal to the meaning of security, territory and authority - concepts central to the idea of the international - but they do not necessarily have to be tied to the state. This thesis offers a critique of International Relations theory combined with a study of climate change. A departure in 'process philosophy' facilitate a rethinking of security, territory and authority as activities rather than things, as verbs rather than nouns. The author shows that a multiplicity of practices of securitization, territorialization, and authorization are visible in the climate issue. The book goes beyond, and reflects upon, the traditional study of 'International Environmental Politics' as a particular subfield of International Relations

  6. Rethinking Socialization Research through the Lens of New Materialism

    Directory of Open Access Journals (Sweden)

    Grit Höppner

    2017-09-01

    Full Text Available In recent decades, socialization research appears to have suffered the loss of its former capacity to explain the processes of becoming a socialized subject in a social environment. In this article, I review socialization theories taking into account assumptions regarding human subjects and their social environments. I confront them with the idea of rethinking dualisms, ontologies, and agencies addressed by the field of new materialism. I propose a new materialist-inspired socialization theory that assumes that humans, knowledge, and material environments become inseparable parts of (gendered socialization processes in a world of constant change. This approach contributes to socialization theory and methodology because it illustrates precisely how humans and non-humans coproduce socialization in situated material-discursive processes.

  7. On Rethinking Our Classrooms: A Critical Pedagogy View

    Directory of Open Access Journals (Sweden)

    Yolanda Samacá Bohórquez

    2012-12-01

    Full Text Available This paper, as its title suggests, introduces some reflections on the importance critical pedagogy as well as awareness-raising practices have in education today, especially in language teacher preparation programs, and how they provide a new opportunity for pre-service teachers to re-think their pedagogical experiences for social transformation. Critical pedagogy (CP as a philosophy of life helps teachers achieve a better understanding of what teaching really entails and raising awareness fosters reflection regarding our practices in educational settings, starting in the language classroom, exploring on the one hand, what pre-service teachers think and perceive about teaching and learning in the context they are involved in, and on the other hand, how those perceptions might influence their educational practices.

  8. Sustainable Refugee Migration: A Rethink towards a Positive Capability Approach

    Directory of Open Access Journals (Sweden)

    Mohammed Al-Husban

    2016-05-01

    Full Text Available A major challenge facing many countries around the world is how to sustainably address the issues of increased numbers of refugee migrants. The refugee migrant “issue” is often heavily political as a high density of migrants in local areas impacts communities (e.g., disrupting local employment, service and culture. Different migrants come with different “baggage” and needs which can be a significant draw on the hosting communities’ resources. This paper argues that sustainable long-term solutions to refugee migrants will require a rethink to the existing dominant models of containment and charity. The paper draws upon insights from a study of a large refugee camp in Jordan over a three-and-a-half-year period, and historical cases of refugee migration. The paper presents a sustainable model that develops long-term capability for the various stakeholder groups.

  9. Rethinking platelet function: thrombocytopenia induced immunodeficiency in critical illness

    DEFF Research Database (Denmark)

    Ostrowski, Sisse R; Johansson, Per Ingemar

    2011-01-01

    Thrombocytopenia in critical illness predicts a poor clinical outcome. Apart from its role in microvascular thrombus formation, it is widely anticipated that this association is indirect rather than causal. Emerging evidence however indicates that platelets are also immune competent cells. Like...... per se results in immunodeficiency through loss of platelet-mediated immune functions, and propose that thrombocytopenia induced immunodeficiency in critical illness in part explain the negative predictive value of low or declining platelet count. We propose that rethinking the risks...... of thrombocytopenia to include not only bleeding but also immunodeficiency and immune dysregulation along with the conduct of studies investigating mechanisms contributing to thrombocytopenia induced poor non-hemorrhagic outcome in critical illness, may be means to improve outcome in these patients through...

  10. Rethinking School Finance. A Policy Issues Paper Prepared for the Chief State School Officers of the Northwest and Pacific.

    Science.gov (United States)

    Hansen, Kenneth H.; And Others

    Ways of rethinking school financial policy issues are examined in this report. This rethinking has evolved from growing recognition of two related principles: school finance as part of public finance; and policy formation as a product of commitments and constraints. Principles of public finance, commitments and constraints are described. Five…

  11. A costal dispersion model

    International Nuclear Information System (INIS)

    Rahm, L.; Nyberg, L.; Gidhagen, L.

    1990-01-01

    A dispersion model to be used off costal waters has been developed. The model has been applied to describe the migration of radionuclides in the Baltic sea. A summary of the results is presented here. (K.A.E)

  12. Wave-equation dispersion inversion

    KAUST Repository

    Li, Jing; Feng, Zongcai; Schuster, Gerard T.

    2016-01-01

    We present the theory for wave-equation inversion of dispersion curves, where the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. The dispersion curves are obtained

  13. Reactimeter dispersion equation

    OpenAIRE

    A.G. Yuferov

    2016-01-01

    The aim of this work is to derive and analyze a reactimeter metrological model in the form of the dispersion equation which connects reactimeter input/output signal dispersions with superimposed random noise at the inlet. It is proposed to standardize the reactimeter equation form, presenting the main reactimeter computing unit by a convolution equation. Hence, the reactimeter metrological characteristics are completely determined by this unit hardware function which represents a transient re...

  14. Fickian dispersion is anomalous

    Science.gov (United States)

    Cushman, John H.; O'Malley, Dan

    2015-12-01

    The thesis put forward here is that the occurrence of Fickian dispersion in geophysical settings is a rare event and consequently should be labeled as anomalous. What people classically call anomalous is really the norm. In a Lagrangian setting, a process with mean square displacement which is proportional to time is generally labeled as Fickian dispersion. With a number of counter examples we show why this definition is fraught with difficulty. In a related discussion, we show an infinite second moment does not necessarily imply the process is super dispersive. By employing a rigorous mathematical definition of Fickian dispersion we illustrate why it is so hard to find a Fickian process. We go on to employ a number of renormalization group approaches to classify non-Fickian dispersive behavior. Scaling laws for the probability density function for a dispersive process, the distribution for the first passage times, the mean first passage time, and the finite-size Lyapunov exponent are presented for fixed points of both deterministic and stochastic renormalization group operators. The fixed points of the renormalization group operators are p-self-similar processes. A generalized renormalization group operator is introduced whose fixed points form a set of generalized self-similar processes. Power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.

  15. Coping with power dispersion?

    DEFF Research Database (Denmark)

    2014-01-01

    The last decades have witnessed a significant shift in policy competences away from central governments in Europe. The reallocation of competences spans over three dimensions: upwards; sideways; and downwards. This collection takes the dispersion of powers as a starting point and seeks to assess...... how the actors involved cope with the new configurations. In this introduction, we discuss the conceptualization of power dispersion and highlight the ways in which the contributions add to this research agenda. We then outline some general conclusions and end by indicating future avenues of research....... Taken together, the collection contributes some answers to the challenge of defining and measuring – in a comparative way – the control and co-ordination mechanisms which power dispersion generates. It also explores the tension between political actors' quest for autonomy and the acknowledgement...

  16. Rethinking project management: A structured literature review with a critical look at the brave new world

    DEFF Research Database (Denmark)

    Svejvig, Per; Andersen, Peter

    2015-01-01

    This paper presents the results of a structured review of the rethinking project management (RPM) literature based on the classification and analysis of 74 contributions and in addition takes a critical look at this brave new world. Through the analysis, a total of 6 overarching categories emerged......: contextualization, social and political aspects, rethinking practice, complexity and uncertainty, actuality of projects and broader conceptualization. These categories cover a broad range of different contributions with diverse and alternative perspectives on project management. The early RPM literature dates back...

  17. Interface, a dispersed architecture

    NARCIS (Netherlands)

    Vissers, C.A.

    1976-01-01

    Past and current specification techniques use timing diagrams and written text to describe the phenomenology of an interface. This paper treats an interface as the architecture of a number of processes, which are dispersed over the related system parts and the message path. This approach yields a

  18. Psychorheology of food dispersions

    Czech Academy of Sciences Publication Activity Database

    Štern, Petr; Panovská, Z.; Pokorný, J.

    2010-01-01

    Roč. 58, č. 1 (2010), s. 29-35 ISSN 0042-790X R&D Projects: GA AV ČR IAA2060404 Institutional research plan: CEZ:AV0Z20600510 Keywords : psychorheology * food dispersions * tomato ketchup * rheology * sensory analysis Subject RIV: BK - Fluid Dynamics Impact factor: 0.553, year: 2010

  19. Dispersal of sticky particles

    Science.gov (United States)

    Reddy, Ramana; Kumar, Sanjeev

    2007-12-01

    In this paper, we show through simulations that when sticky particles are broken continually, particles are dispersed into fine dust only if they are present in a narrow range of volume fractions. The upper limit of this range is 0.20 in the 2D and 0.10 in the 3D space. An increase in the dimensionality of space reduces the upper limit nearly by a factor of two. This scaling holds for dispersal of particles in hyperdimensional space of dimensions up to ten, the maximum dimension studied in this work. The maximum values of volume fractions obtained are significantly lower than those required for close packing and random packing of discs in 2D and spheres in 3D space. These values are also smaller than those required for critical phenomena of cluster percolation. The results obtained are attributed to merger cascades of sticky particles, triggered by breakup events. A simple theory that incorporates this cascade is developed to quantitatively explain the observed scaling of the upper limit with the dimensionality of space. The theory also captures the dynamics of the dispersal process in the corresponding range of particle volume fractions. The theory suggests that cascades of order one and two predominantly decide the upper limit for complete dispersal of particles.

  20. Analogy in causal inference: rethinking Austin Bradford Hill's neglected consideration.

    Science.gov (United States)

    Weed, Douglas L

    2018-05-01

    The purpose of this article was to rethink and resurrect Austin Bradford Hill's "criterion" of analogy as an important consideration in causal inference. In epidemiology today, analogy is either completely ignored (e.g., in many textbooks), or equated with biologic plausibility or coherence, or aligned with the scientist's imagination. None of these examples, however, captures Hill's description of analogy. His words suggest that there may be something gained by contrasting two bodies of evidence, one from an established causal relationship, the other not. Coupled with developments in the methods of systematic assessments of evidence-including but not limited to meta-analysis-analogy can be restructured as a key component in causal inference. This new approach will require that a collection-a library-of known cases of causal inference (i.e., bodies of evidence involving established causal relationships) be developed. This library would likely include causal assessments by organizations such as the International Agency for Research on Cancer, the National Toxicology Program, and the United States Environmental Protection Agency. In addition, a process for describing key features of a causal relationship would need to be developed along with what will be considered paradigm cases of causation. Finally, it will be important to develop ways to objectively compare a "new" body of evidence with the relevant paradigm case of causation. Analogy, along with all other existing methods and causal considerations, may improve our ability to identify causal relationships. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Rethink, Reform, Reenter: An Entrepreneurial Approach to Prison Programming.

    Science.gov (United States)

    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. © The Author(s) 2014.

  2. Rethinking Global Water Governance for the 21st Century

    Science.gov (United States)

    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.

  3. Rethinking Approaches to Strategic Stability in the 21st Century

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Brian [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-02-01

    Lawrence Livermore National Laboratory (LLNL) hosted a two-day conference on rethinking approaches to strategic stability in the 21st century on October 20-21, 2016 in Livermore, CA. The conference was jointly convened by Lawrence Livermore, Los Alamos, and Sandia National Laboratories, and was held in partnership with the United States Department of State’s Bureau of Arms Control, Verification and Compliance. The conference took place at LLNL’s Center for Global Security Research (CGSR) and included a range of representatives from U.S. government, academic, and private institutions, as well as representatives from U.S. allies in Europe and Asia.The following summary covers topics and discussions from each of the panels. It is not intended to capture every point in detail, but seeks to outline the range of views on these complex and inter-related issues while providing a general overview of the panel topics and discussions that took place. The conference was held under the Chatham House rule and does not attribute any remarks to any specific individual or institution. The views reflected in this report do not represent the United States Government, Department of State, or the national laboratories.

  4. Contested Development in Indonesia: Rethinking Ethnicity and Gender in Mining

    Directory of Open Access Journals (Sweden)

    Kristina Großmann

    2017-06-01

    Full Text Available Page Header User Username Password Remember me Notifications View Subscribe Information For Readers Home About Login Register Search Current Archives Submit your Article Leave the Editoral Platform and Return to our Website Home > Vol 10, No 1 (2017 > Großmann Contested Development in Indonesia: Rethinking Ethnicity and Gender in Mining Kristina Großmann, Martina Padmanabhan, Katharina von Braun Abstract This article reviews the literature on the relationship between gender and ethnicity in Indonesia’s mining sector and outlines shortcomings and prospects for further research. Recent studies on mining and gender focus predominantly on women and how they are negatively affected by mining. Ethnicity, although a growing asset in struggles on environmental transformations, is hardly included in research on mining. The intertwinement of ethnicity and gender in elaborations on mining is often depicted in literature of development programs and environmental organizations in which indigenous women are homogenized as marginalized victims. We argue, however, for a multidimensional approach on mining that takes into account the institutionalization of gender and ethnicity in mining governance as well as the role of gender and ethnic identities. Feminist political ecology and institutional analysis are pointing the way for such an approach. Furthermore, other relevant categories such as class, age, or status should be considered in the analysis of the complex and multidimensional environmental transformations of the mining sector in Indonesia.

  5. The Pastoral Power of Technology. Rethinking Alienation in Digital Culture

    Directory of Open Access Journals (Sweden)

    Katarina Giritli Nygren

    2012-05-01

    Full Text Available The purpose of this paper is to bring Foucault’s elaboration on ‘the pastoral modalities of power’ into play in order to rethink alienation in digital culture. Pastoral power is not displacing other conceptions of power, but provides another level of analysis involved in the forging of reasonable responsible subjects willing and able to sustain other conceptions of power. We will draw particularly on the early writings of Marx and the more recent poststructuralist developments concerning hegemony and superstructure in relation to technology. Technology as such is analysed in terms of repercussions of ‘design of the machine’ in industrial technological contexts and ‘design of digital culture’ in digital technological contexts. Pastoral power not only directs our focus to the making of technologies, but also to the making of individuals capable of taking on the responsibilities of technologies. This means that it is necessary to take on the notion of effective power of ideologies and their material reality.

  6. Rethinking Social Contracts: Building Resilience in a Changing Climate

    Directory of Open Access Journals (Sweden)

    Karen O'Brien

    2009-12-01

    Full Text Available Social contracts play an important role in defining the reciprocal rights, obligations, and responsibilities between states and citizens. Climate change is creating new challenges for both states and citizens, inevitably forcing a rethinking of existing and evolving social contracts. In particular, the social arrangements that enhance the well-being and security of both present and future generations are likely to undergo dramatic transformations in response to ecosystem changes, more extreme weather events, and the consequences of social-ecological changes in distant locations. The types of social contracts that evolve in the face of a changing climate will have considerable implications for adaptation policies and processes. We consider how a resilience approach can contribute to new social contracts in the face of uncertainty and change. Examples from Norway, New Zealand, and Canada show how resilience thinking provides a new way of looking at social contracts, emphasizing the dynamics, links, and complexity of coupled social-ecological systems. Resilience thinking provides valuable insights on the characteristics of a new social contract, and social contract theory provides some insights on creating resilience and human security in a warming world.

  7. Dispersed flow film boiling

    International Nuclear Information System (INIS)

    Andreani, M.; Yadigaroglu, G.

    1989-12-01

    Dispersed flow film boiling is the heat transfer regime that occurs at high void fractions in a heated channel. The way this transfer mode is modelled in the NRC computer codes (RELAP5 and TRAC) and the validity of the assumption and empirical correlations used is discussed. An extensive review of the theoretical and experimental work related with heat transfer to highly dispersed mixtures reveals the basic deficiencies of these models: the investigation refers mostly to the typical conditions of low rate bottom reflooding, since the simulation of this physical situation by the computer codes has often showed poor results. The alternative models that are available in the literature are reviewed, and their merits and limits are highlighted. The modification that could improve the physics of the models implemented in the codes are identified. (author) 13 figs., 123 refs

  8. Working document dispersion models

    International Nuclear Information System (INIS)

    Dop, H. van

    1988-01-01

    This report is a summary of the most important results from June 1985 of the collaboration of the RIVM (Dutch National Institute for Public Health and Environment Hygiene) and KNMI (Royal Dutch Meteorologic Institute) on the domain of dispersion models. It contains a short description of the actual SO x /NO x -model. Furthermore it contains recommendations for modifications of some numerical-mathematical aspects and an impulse to a more complete description of chemical processes in the atmosphere and the (wet) deposition process. A separate chapter is devoted to the preparation of meteorologic data which are relevant for dispersion as well as atmospheric chemistry and deposition. This report serves as working document for the final formulation of a acidifying- and oxidant-model. (H.W.). 69 refs.; 51 figs.; 13 tabs.; 3 schemes

  9. Spatially Dispersed Employee Recovery

    DEFF Research Database (Denmark)

    Hvass, Kristian Anders; Torfadóttir, Embla

    2014-01-01

    Employee recovery addresses either employee well-being or management's practices in aiding employees in recovering themselves following a service failure. This paper surveys the cabin crew at a small, European, low-cost carrier and investigates employees' perceptions of management practices to aid...... personnel achieve service recovery. Employee recovery within service research often focuses on front-line employees that work in a fixed location, however a contribution to the field is made by investigating the recovery of spatially dispersed personnel, such as operational personnel in the transport sector......, who have a work place away from a fixed or central location and have minimal management contact. Results suggest that the support employees receive from management, such as recognition, information sharing, training, and strategic awareness are all important for spatially dispersed front...

  10. Heat dispersion in rivers

    International Nuclear Information System (INIS)

    Shaw, T.L.

    1974-01-01

    One of the tasks of the Sonderforschungsbereich 80 is to study the dispersion of heat discharged into rivers and other bodies of water and to develop methods which permit prediction of detrimental effects caused by the heated discharges. In order to help the SFB 80 to specify this task, Dr. Shaw, lecturer of Civil Engineering at the Bristol University, conducted a literature survey on heat-dispersion studies during the two months which he spent as a visiting research fellow with the SFB 80 at the University of Karlsruhe in the summer of 1973. The following report is the outcome of this survey. It gives Dr. Shaw's assessment of the present state of knowledge - based almost exclusively on literature in the English language - and compares this with the knowledge required by river planners. The apparent discrepancy leads to suggestions for future research. Selected references as well as a representative bibliography can be found at the end of the report. (orig.) [de

  11. Rethinking the Modernist Curriculum with Habermas's Concept of Self-Critical Appropriation

    Science.gov (United States)

    Sarid, Ariel

    2017-01-01

    The primary objective of this paper is to discuss the implications of applying Habermas's concept of self-critical appropriation for rethinking the structure of the modernist curriculum, specifically the organization of school subjects and instruction time devoted to each of them. To this end, the paper examines Habermas's differentiation between…

  12. Rethinking Ostia : a spatial enquiry into the urban society of Rome's imperial port-town

    NARCIS (Netherlands)

    Stöger, Johanna

    2011-01-01

    Rethinking Ostia presents an archaeological and spatial approach to Roman urbanism, focused on Rome’s port city. The study proceeds along the route of a ‘spatial investigation’, offering a fresh look and detailed insights into the past society and the built environment of this port town. Following a

  13. History versus Equilibrium Revisited: Rethinking Neoclassical Economics as the Foundation of Business Education

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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…

  15. Rethinking the making and breaking of traditional and statutory institutions in post-Nkrumah Ghana

    DEFF Research Database (Denmark)

    Stacey, Paul Austin

    2016-01-01

    This article examines a complex dispute over the jurisdictions of traditional and statutory institutions that traversed shifts in forms of government in Ghana for nearly a decade following the ousting of Kwame Nkrumah in February 1966. The analysis emphasizes underlying processes of continuity...... a rethinking of the notion that the post-Nkrumah era heralded a state-initiated revival of traditional institutions....

  16. Rethinking the Learning Society: Giorgio Agamben on Studying, Stupidity, and Impotence

    Science.gov (United States)

    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,…

  17. Crisis, value, and hope: rethinking the economy. An introduction to supplement 9

    NARCIS (Netherlands)

    Narotzky, S.; Besnier, N.

    2014-01-01

    Crisis, value, and hope are three concepts whose intersection and mutual constitution open the door for a rethinking of the nature of economic life away from abstract models divorced from the everyday realities of ordinary people, the inadequacies of which the current world economic crisis has

  18. A new future for business? Rethinking management theory and business strategy

    NARCIS (Netherlands)

    Hahn, T.; Kolk, A.; Winn, M.

    2010-01-01

    In this introductory article, we discuss the need for a rethinking of the theoretical foundations of management and the practice of business strategy in view of a range of social, environmental and ethical challenges that highlight the limits of ‘business as usual’. Calls for a reconsideration of

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

    Science.gov (United States)

    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…

  20. re-thinking ethical leadership in kenya: adopting a new paradigm

    African Journals Online (AJOL)

    The purpose of this article is to provoke students and scholars in the field of ethics to re-think and develop new approaches in the practice of ethical leadership. Many authors have written on the subject of leadership values and ethics, yet, the world continues to witness increasing cases of corruption and executive ...

  1. Rethinking Nutrition: Connecting Science and Practice in Early Childhood Settings, Revised Edition

    Science.gov (United States)

    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…

  2. Little Room for Capacitation: Rethinking Bourdieu on Pedagogy as Symbolic Violence

    Science.gov (United States)

    Watkins, Megan

    2018-01-01

    In Bourdieu's early work on education, he declares that "All pedagogic action (PA) is objectively symbolic violence insofar as it is the imposition of a cultural arbitrary by an arbitrary power". This article rethinks Bourdieu's proposition. It questions whether all PA is symbolic violence and the very notion of a cultural arbitrary upon…

  3. ‘One step beyond’ – Re-Think Athens, towards a new city centre

    NARCIS (Netherlands)

    Klemm, W.

    2013-01-01

    On the 27 February it is announced at the Onassis Cultural Centre in Athens (=opdrachtgever) that the OKRA team of OKRA in collaboration with Mixst urbanism and Wageningen University, has won the prestigious international architectural competition ReThink Athens, towards a new city centre. The team

  4. Climate change or variable weather: Rethinking Danish homeowners' perceptions of floods and climate

    DEFF Research Database (Denmark)

    Baron, Nina; Petersen, Lars Kjerulf

    2015-01-01

    Climate scenarios predict that an effect of climate change will be more areas at risk of extensive flooding. This article builds on a qualitative case study of homeowners in the flood-prone area of Lolland in Denmark and uses the theories of Tim Ingold and Bruno Latour to rethink the way we under...

  5. Taylor dispersion of nanoparticles

    Science.gov (United States)

    Balog, Sandor; Urban, Dominic A.; Milosevic, Ana M.; Crippa, Federica; Rothen-Rutishauser, Barbara; Petri-Fink, Alke

    2017-08-01

    The ability to detect and accurately characterize particles is required by many fields of nanotechnology, including materials science, nanotoxicology, and nanomedicine. Among the most relevant physicochemical properties of nanoparticles, size and the related surface-to-volume ratio are fundamental ones. Taylor dispersion combines three independent phenomena to determine particle size: optical extinction, translational diffusion, and sheer-enhanced dispersion of nanoparticles subjected to a steady laminar flow. The interplay of these defines the apparent size. Considering that particles in fact are never truly uniform nor monodisperse, we rigorously address particle polydispersity and calculate the apparent particle size measured by Taylor dispersion analysis. We conducted case studies addressing aqueous suspensions of model particles and large-scale-produced "industrial" particles of both academic and commercial interest of various core materials and sizes, ranging from 15 to 100 nm. A comparison with particle sizes determined by transmission electron microscopy confirms that our approach is model-independent, non-parametric, and of general validity that provides an accurate account of size polydispersity—independently on the shape of the size distribution and without any assumption required a priori.

  6. Nozzle for electric dispersion reactor

    Science.gov (United States)

    Sisson, W.G.; Basaran, O.A.; Harris, M.T.

    1995-11-07

    A nozzle for an electric dispersion reactor includes two concentric electrodes, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode. 4 figs.

  7. World Peace Through Law: Rethinking an Old Theory

    Directory of Open Access Journals (Sweden)

    James Ranney

    2012-10-01

    Full Text Available The author sets about re-thinking the old concept of “World Peace Through Law” (WPTL, meaning replacing the use of international force with the global rule of law. He traces the history of the WPTL concept back to the British legal philosopher Jeremy Bentham, whose 1789 ‘Plan for an Universal and Perpetual Peace’ proposed “a plan of general and permanent pacification for all Europe,” with troop reductions(especially in naval forces and “a Common Court of Judicature” to resolve differences between nations. The author’s 21st century version of WPTL bears an uncanny resemblance to Bentham’s original proposal, calling for: 1 arms reductions (including abolition of nuclear weapons; 2 a four-stage comprehensive system of compulsory alternative dispute resolution(compulsory negotiation, mediation, arbitration, and adjudication; and 3 various enforcement mechanisms, including an international peace force.The author argues that now is the time for adoption of what is a mainstream middle-of-the-road proposition (previously adopted by four past American presidents, including Theodore Roosevelt, William Howard Taft, Dwight David Eisenhower, and John F. Kennedy that is neither “too little” (our current strategy of “collective insecurity” nor “too much” (world government or world federalism. Instead, WPTL calls for only 1 arms reductions, not general and complete disarmament; 2 compulsory international alternative dispute resolution systems, not a global legislature; and 3 means of effective enforcement (including an international police force, not pacifism.The whole concept of WPTL has been sadly neglected over the past half century. It is time to take a new look at the concept in this, the nuclear age.

  8. A Literary Perspective on the Environment: Rethinking Development through Art

    Directory of Open Access Journals (Sweden)

    Davi Silva Gonçalves

    2014-04-01

    Full Text Available Due to the environmental crisis that chokes contemporaneity, it is of paramount importance for society to rethink our physical and abstract behaviours towards nature. Ecocriticism, providing a bridge between literature and nature, allows us to reorganise proven problematic notions, such as progress and development, which tend to gradually separate human beings from the space they occupy. Such separation results in a detachment that hinders our ability to transcend metropolitan, narrow-minded, biased judgments regarding the future of developing countries like Brazil, and perhaps artistic tools like literature are the only ones capable of broadening our reflections for inviting us to go beyond preconditioned perspectives. This article aims at showing how Milton Hatoum’s novel The Brothers (2000 implies that we must look for distinct possibilities of developing our spaces, more specifically the Amazon, and, through the analysis of the book as well as the impact of development on the region, the dialogue between literature and nature is proposed. First the theoretical approach on both nature and literature is delineated, followed by a discussion on how important it is to (reconnect subjects and environment, and then by analysing the novel’s characters which evince the side effects of “progress” and “growth” in the Amazonian region. The result is a problematisation of normative dichotomies such as savage/civilised, past/future, subject/space, underdeveloped/developed, and the conclusion that, for development to stop being detrimental to nature, we shall avoid believing in a “faceless environment” (Campbell, 18, that is, one needs to start observing the impact of such development on the lives of those inevitably and automatically marginalised by it.

  9. Rethinking Prefigurative Politics: Introduction to the Special Thematic Section

    Directory of Open Access Journals (Sweden)

    Flora Cornish

    2016-05-01

    Full Text Available This special thematic section responds to the 21st century proliferation of social movements characterised by the slogans ‘another world is possible’ and ‘be the change you want to see’. It explores prefigurative politics as a means of instantiating radical social change in a context of widening global inequalities, climate change, and the crises and recoveries of neoliberal global capitalism. ‘Prefigurative politics’ refers to a range of social experiments that both critique the status quo and offer alternatives by implementing radically democratic practices in pursuit of social justice. This collection of articles makes the case for psychologists to engage with prefigurative politics as sites of psychological and social change, in the dual interests of understanding the world and changing it. The articles bridge psychology and politics in three different ways. One group of articles brings a psychological lens to political phenomena, arguing that attention to the emotional, relational and intergroup dynamics of prefigurative politics is required to understand their trajectories, challenges, and impacts. A second group focuses a political lens on social settings traditionally framed as psychological sites of well-being, enabling an understanding of their political nature. The third group addresses the ‘border tensions’ of the psychological and the political, contextualising and historicising the instantiation of prefigurative ideals and addressing tensions that arise between utopian ideals and various internal and external constraints. This introduction to the special section explores the concept and contemporary debates concerning prefigurative politics, outlines the rationale for a psychological engagement with this phenomenon, and presents the articles in the special thematic section. The general, prefigurative, aim is to advance psychology’s contribution to rethinking and remaking the world as it could be, not only

  10. Tracer dispersion - experiment and CFD

    International Nuclear Information System (INIS)

    Zitny, R.

    2004-01-01

    Description of tracer distribution by means of dispersion models is a method successfully used in process engineering for fifty years. Application of dispersion models in reactor engineering for characterization of flows in column apparatus, heat exchangers, etc. is summarized and experimental tracer techniques as well as CFD methods for dispersion coefficients evaluation are discussed. Possible extensions of thermal axial dispersion model (ADM) and a core-wall ADM model suitable for description of tracer dispersion in laminar flows are suggested as well as CFD implementation as 1D finite elements. (author)

  11. High density dispersion fuel

    International Nuclear Information System (INIS)

    Hofman, G.L.

    1996-01-01

    A fuel development campaign that results in an aluminum plate-type fuel of unlimited LEU burnup capability with an uranium loading of 9 grams per cm 3 of meat should be considered an unqualified success. The current worldwide approved and accepted highest loading is 4.8 g cm -3 with U 3 Si 2 as fuel. High-density uranium compounds offer no real density advantage over U 3 Si 2 and have less desirable fabrication and performance characteristics as well. Of the higher-density compounds, U 3 Si has approximately a 30% higher uranium density but the density of the U 6 X compounds would yield the factor 1.5 needed to achieve 9 g cm -3 uranium loading. Unfortunately, irradiation tests proved these peritectic compounds have poor swelling behavior. It is for this reason that the authors are turning to uranium alloys. The reason pure uranium was not seriously considered as a dispersion fuel is mainly due to its high rate of growth and swelling at low temperatures. This problem was solved at least for relatively low burnup application in non-dispersion fuel elements with small additions of Si, Fe, and Al. This so called adjusted uranium has nearly the same density as pure α-uranium and it seems prudent to reconsider this alloy as a dispersant. Further modifications of uranium metal to achieve higher burnup swelling stability involve stabilization of the cubic γ phase at low temperatures where normally α phase exists. Several low neutron capture cross section elements such as Zr, Nb, Ti and Mo accomplish this in various degrees. The challenge is to produce a suitable form of fuel powder and develop a plate fabrication procedure, as well as obtain high burnup capability through irradiation testing

  12. Spurious dispersion effects at FLASH

    International Nuclear Information System (INIS)

    Prat, Eduard

    2009-07-01

    The performance of the Free-Electron Laser (FEL) process imposes stringent demands on the transverse trajectory and size of the electron beam. Since transverse dispersion changes off-energy particle trajectories and increases the effective beam size, dispersion must be controlled. This thesis treats the concept of dispersion in linacs, and analyses the impact of dispersion on the electron beam and on the FEL process. It presents generation mechanisms for spurious dispersion, quantifying its importance for FLASH (Free-electron Laser in Hamburg) and the XFEL (European X-ray Free-Electron Laser). A method for measuring and correcting dispersion and its implementation in FLASH is described. Experiments of dispersion e ects on the transverse beam quality and on the FEL performance are presented. (orig.)

  13. Spurious dispersion effects at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Prat, Eduard

    2009-07-15

    The performance of the Free-Electron Laser (FEL) process imposes stringent demands on the transverse trajectory and size of the electron beam. Since transverse dispersion changes off-energy particle trajectories and increases the effective beam size, dispersion must be controlled. This thesis treats the concept of dispersion in linacs, and analyses the impact of dispersion on the electron beam and on the FEL process. It presents generation mechanisms for spurious dispersion, quantifying its importance for FLASH (Free-electron Laser in Hamburg) and the XFEL (European X-ray Free-Electron Laser). A method for measuring and correcting dispersion and its implementation in FLASH is described. Experiments of dispersion e ects on the transverse beam quality and on the FEL performance are presented. (orig.)

  14. Dispersion stability of thermal nanofluids

    Directory of Open Access Journals (Sweden)

    Fan Yu

    2017-10-01

    Full Text Available Thermal nanofluids, the engineered fluids with dispersed functional nanoparticles, have exhibited extraordinary thermophysical properties and added functionalities, and thus have enabled a broad range of important applications. The poor dispersion stability of thermal nanofluids, however, has been considered as a long-existing issue that limits their further development and practical application. This review overviews the recent efforts and progresses in improving the dispersion stability of thermal nanofluids such as mechanistic understanding of dispersion behavior of nanofluids, examples of both water-based and oil-based nanofluids, strategies to stabilize nanofluids, and characterization techniques for dispersion behavior of nanofluids. Finally, on-going research needs, and possible solutions to research challenges and future research directions in exploring stably dispersed thermal nanofluids are discussed. Keywords: Thermal nanofluids, Dispersion, Aggregation, Electrostatic stabilization, Steric stabilization

  15. Phonon dispersion in vanadium

    International Nuclear Information System (INIS)

    Ivanov, A.S.; Rumiantsev, A.Yu.

    1999-01-01

    Complete text of publication follows. Phonon dispersion curves in Vanadium metal are investigated by neutron inelastic scattering using three-axis spectrometers. Due to extremely low coherent scattering amplitude of neutrons in natural isotope mixture of vanadium the phonon frequencies could be determined in the energy range below about 15 meV. Several phonon groups were measured with the polarised neutron scattering set-up. It is demonstrated that the intensity of coherent inelastic scattering observed in the non-spin-flip channel vanishes in the spin-flip channel. The phonon density of states is measured on a single crystal keeping the momentum transfer equal to a vector of reciprocal lattice where the coherent inelastic scattering is suppressed. Phonon dispersion curves in vanadium, as measured by neutron and earlier by X-ray scattering, are described in frames of a charge-fluctuation model involving monopolar and dipolar degrees of freedom. The model parameters are compared for different transition metals with body-centred cubic-structure. (author)

  16. Dispersion and current measurements

    International Nuclear Information System (INIS)

    Boelskifte, S.

    1986-04-01

    A model for the simulation of particle movements in water should incorporate the mutual distance dependent correlation. As long as reliable data are given accessible a model can be created of the dispersion in a given area from a statistical description of turbulence. Current measurements have been performed in an area north of the Swedish nuclear power plant Barsebaeck, and statistical time series analysis have made it possible to estimate multivariate autoregressive moving-average (ARMA) models for these data using the Box-Jenkins method. The correlation structure for the area has been investigated in detail. Transport and dispersion models for the marine environment are used in estimating doses to the population from the aquatic food chain. Some of these models are described with special emphasis on the time and length scales they cover. Furthermore, to illustrate the background of the simulation model, short introductuions are given to health physics, time series analysis, and turbulence theory. Analysis of the simulation model shows the relative importance of the different parameters. The model can be expanded to conditional simulation, where the current measurements are used directly to simulate the movement of one of the particles. Results from the model are also compared to results from a sampling of bioindicators (Fucus vesiculosus) along the Danish coast. The reliability of bioindicators in this kind of experiment is discussed. (author)

  17. Quantum optical rotatory dispersion

    Science.gov (United States)

    Tischler, Nora; Krenn, Mario; Fickler, Robert; Vidal, Xavier; Zeilinger, Anton; Molina-Terriza, Gabriel

    2016-01-01

    The phenomenon of molecular optical activity manifests itself as the rotation of the plane of linear polarization when light passes through chiral media. Measurements of optical activity and its wavelength dependence, that is, optical rotatory dispersion, can reveal information about intricate properties of molecules, such as the three-dimensional arrangement of atoms comprising a molecule. Given a limited probe power, quantum metrology offers the possibility of outperforming classical measurements. This has particular appeal when samples may be damaged by high power, which is a potential concern for chiroptical studies. We present the first experiment in which multiwavelength polarization-entangled photon pairs are used to measure the optical activity and optical rotatory dispersion exhibited by a solution of chiral molecules. Our work paves the way for quantum-enhanced measurements of chirality, with potential applications in chemistry, biology, materials science, and the pharmaceutical industry. The scheme that we use for probing wavelength dependence not only allows one to surpass the information extracted per photon in a classical measurement but also can be used for more general differential measurements. PMID:27713928

  18. Metapopulation extinction risk: dispersal's duplicity.

    Science.gov (United States)

    Higgins, Kevin

    2009-09-01

    Metapopulation extinction risk is the probability that all local populations are simultaneously extinct during a fixed time frame. Dispersal may reduce a metapopulation's extinction risk by raising its average per-capita growth rate. By contrast, dispersal may raise a metapopulation's extinction risk by reducing its average population density. Which effect prevails is controlled by habitat fragmentation. Dispersal in mildly fragmented habitat reduces a metapopulation's extinction risk by raising its average per-capita growth rate without causing any appreciable drop in its average population density. By contrast, dispersal in severely fragmented habitat raises a metapopulation's extinction risk because the rise in its average per-capita growth rate is more than offset by the decline in its average population density. The metapopulation model used here shows several other interesting phenomena. Dispersal in sufficiently fragmented habitat reduces a metapopulation's extinction risk to that of a constant environment. Dispersal between habitat fragments reduces a metapopulation's extinction risk insofar as local environments are asynchronous. Grouped dispersal raises the effective habitat fragmentation level. Dispersal search barriers raise metapopulation extinction risk. Nonuniform dispersal may reduce the effective fraction of suitable habitat fragments below the extinction threshold. Nonuniform dispersal may make demographic stochasticity a more potent metapopulation extinction force than environmental stochasticity.

  19. Rethinking the city through memory and meaning of place

    Directory of Open Access Journals (Sweden)

    Sanchez-Gonzalez, Diego

    2016-03-01

    Full Text Available In the city the understanding of each location involves an approach to the processes and strategies of power behind socio-spatial dynamics associated with urban segregation and social exclusion. However, the intellectual weakness of the interpretations of the urban phenomenon requires rethinking the concepts and methodological tools to face the challenges of urban development in a context of economic instability, population aging and climate change. In this regard, various experts invite us to unravel the complex reality behind urban social processes and give us grounds to encourage political commitment and avoid indifference. Precisely against apathy and widespread resignation on urban issues and growing inequality, there is a pressing need to experience different initiatives aimed at developing social commitment, from consensus-building anchored in dialogue and memory community. En la ciudad la comprensión de cada lugar implica un acercamiento a los procesos y estrategias de poder que hay detrás de las dinámicas socioespaciales asociadas a la segregación urbana y exclusión social. Sin embargo, la debilidad intelectual de las interpretaciones sobre el fenómeno urbano obliga a replantear los conceptos e instrumentos metodológicos para enfrentar los retos del desarrollo urbano en un contexto de inestabilidad económica, envejecimiento demográfico y de cambio climático. Al respecto, diferentes expertos nos invitan a desentrañar la compleja realidad que hay detrás de los procesos sociales urbanos y nos dan argumentos para propiciar el compromiso político y evitar la indiferencia. Precisamente, frente a la apatía y la resignación generalizadas sobre la cuestión urbana y la creciente desigualdad, existe una necesidad apremiante de experimentar distintas iniciativas encaminadas a desarrollar el compromiso social, a partir de la búsqueda de consensos anclados en el diálogo y la memoria de la comunidad.

  20. Relativistic plasma dispersion functions

    International Nuclear Information System (INIS)

    Robinson, P.A.

    1986-01-01

    The known properties of plasma dispersion functions (PDF's) for waves in weakly relativistic, magnetized, thermal plasmas are reviewed and a large number of new results are presented. The PDF's required for the description of waves with small wave number perpendicular to the magnetic field (Dnestrovskii and Shkarofsky functions) are considered in detail; these functions also arise in certain quantum electrodynamical calculations involving strongly magnetized plasmas. Series, asymptotic series, recursion relations, integral forms, derivatives, differential equations, and approximations for these functions are discussed as are their analytic properties and connections with standard transcendental functions. In addition a more general class of PDF's relevant to waves of arbitrary perpendicular wave number is introduced and a range of properties of these functions are derived

  1. Statistical Thermodynamics of Disperse Systems

    DEFF Research Database (Denmark)

    Shapiro, Alexander

    1996-01-01

    Principles of statistical physics are applied for the description of thermodynamic equilibrium in disperse systems. The cells of disperse systems are shown to possess a number of non-standard thermodynamic parameters. A random distribution of these parameters in the system is determined....... On the basis of this distribution, it is established that the disperse system has an additional degree of freedom called the macro-entropy. A large set of bounded ideal disperse systems allows exact evaluation of thermodynamic characteristics. The theory developed is applied to the description of equilibrium...

  2. Geometry of physical dispersion relations

    International Nuclear Information System (INIS)

    Raetzel, Dennis; Rivera, Sergio; Schuller, Frederic P.

    2011-01-01

    To serve as a dispersion relation, a cotangent bundle function must satisfy three simple algebraic properties. These conditions are derived from the inescapable physical requirements that local matter field dynamics must be predictive and allow for an observer-independent notion of positive energy. Possible modifications of the standard relativistic dispersion relation are thereby severely restricted. For instance, the dispersion relations associated with popular deformations of Maxwell theory by Gambini-Pullin or Myers-Pospelov are not admissible. Dispersion relations passing the simple algebraic checks derived here correspond to physically admissible Finslerian refinements of Lorentzian geometry.

  3. Recurrence: A Filmosophic Re-thinking of A Long Story/ Uzun Hikaye

    Directory of Open Access Journals (Sweden)

    Basak Goksel Demiray

    2014-10-01

    Full Text Available This study will re-think A Long Story under the guidance of Daniel Frampton’s perspective of “filmosophy” which theorises film as a ‘being’ independent from any external effect, and acknowledges that film  has a ‘mind’ and is ‘able to think’ in its own way. To be clear on re-thinking how A Long Story ‘thinks’ of the concept of ‘recurrence’ in its dramatic structure, this study first will give a detailed explanation of “filmosophy”. Then, it will elaborate the particular ‘intentions’ and ‘choices’ that the film is responsible of whilst constructing itself upon the idea of ‘recurrence’. Finally, this study will focus on a particular scene and explain its significance on locating ‘recurrence’ as the ‘whole knowledge’ the film keeps in mind.

  4. Theater of "bóias-frias": rethinking anthropology of performance

    Directory of Open Access Journals (Sweden)

    John C. Dawsey

    2006-01-01

    Full Text Available The anthropology of performance, as understood by Victor Turner, provides interesting perspectives for the analysis of what may be referred to as the "theater of bóias-frias". Conversely, this theater may be of special interest for purposes of rethinking some of the main propositions which have arisen on the borders between anthropology and performance. Considering the specificity of "the practice which calculates the place from which one views things" of this theater, several topics present themselves as guidelines for the text which follows: 1 social dramas, 2 relations between social and aesthetic dramas, 3 symbols and montage, and 4 theater paradigms in anthropology. In this exercise to rethink some of the "classic" contributions of Victor Turner, Erving Goffman, and Richard Schechner, "elective affinities" have been found between, on the one hand, the writings of Walter Benjamin and Brechtian theater, and, on the other, the dramaturgical principles of the bóias-frias.

  5. Dispersion bias, dispersion effect, and the aerosol-cloud conundrum

    International Nuclear Information System (INIS)

    Liu Yangang; Daum, Peter H; Guo Huan; Peng Yiran

    2008-01-01

    This work examines the influences of relative dispersion (the ratio of the standard deviation to the mean radius of the cloud droplet size distribution) on cloud albedo and cloud radiative forcing, derives an analytical formulation that accounts explicitly for the contribution from droplet concentration and relative dispersion, and presents a new approach to parameterize relative dispersion in climate models. It is shown that inadequate representation of relative dispersion in climate models leads to an overestimation of cloud albedo, resulting in a negative bias of global mean shortwave cloud radiative forcing that can be comparable to the warming caused by doubling CO 2 in magnitude, and that this dispersion bias is likely near its maximum for ambient clouds. Relative dispersion is empirically expressed as a function of the quotient between cloud liquid water content and droplet concentration (i.e., water per droplet), yielding an analytical formulation for the first aerosol indirect effect. Further analysis of the new expression reveals that the dispersion effect not only offsets the cooling from the Twomey effect, but is also proportional to the Twomey effect in magnitude. These results suggest that unrealistic representation of relative dispersion in cloud parameterization in general, and evaluation of aerosol indirect effects in particular, is at least in part responsible for several outstanding puzzles of the aerosol-cloud conundrum: for example, overestimation of cloud radiative cooling by climate models compared to satellite observations; large uncertainty and discrepancy in estimates of the aerosol indirect effect; and the lack of interhemispheric difference in cloud albedo.

  6. Rethinking workforce boundaries: roles, responsibilities and skill mix and readiness for change in general practice

    OpenAIRE

    Topping, Annie; Nkosana Nyawata, Idah; Stephenson, John; Featherstone, Valerie A.

    2012-01-01

    Title: Rethinking workforce boundaries: roles, responsibilities and skill mix and readiness for change in general practice \\ud The Problem \\ud The last 10 years has seen major changes in the way services are delivered in primary care. Skill mix, has offered many practices real opportunities for doing things differently. As the introduction of advanced nurse practitioners (ANPs) and health care assistants (HCAs) into the primary care workforce demonstrate. While workforce redesign has its crit...

  7. Rethinking the Role of Grey Literature in the Fourth Industrial Revolution

    OpenAIRE

    Savić, Dobrica

    2017-01-01

    This paper examines the potential impact of the emerging Fourth Industrial Revolution on grey literature and the challenges it will bring to the information management profession. Based on analysis of the most prevalent current trends and developments, it appears we will need to rethink the defi nition of grey literature, its creation and types, processing, storage, sustainability and usability. Information professionals, including the grey literature ones, will require training and new knowl...

  8. Review: Henry E. Brady & David Collier (Hrsg.) (2004). Rethinking Social Inquiry: Diverse Tools, Shared Standards

    OpenAIRE

    Catón, Matthias

    2006-01-01

    Das Buch Rethinking Social Inquiry, herausgegeben von Henry E. BRADY und David COLLIER, ist eine Antwort auf den Band von KING, KEOHANE und VERBA (1994), in dem versucht wird, Standards der quantitativen Forschung in der qualitativen Forschung einzuführen. Die Autoren des hier rezensierten Buchs kritisieren viele der Vorschläge, da sie argumentieren, dass qualitative Forschung anderer Werkzeuge bedürfe. Trotzdem stimmen sie zu, dass die Grundlagen des Forschungsaufbaus ähnlich sind. Das Buch ...

  9. Review: Henry E. Brady & David Collier (Eds.) (2004). Rethinking Social Inquiry: Diverse Tools, Shared Standards

    OpenAIRE

    Matthias Catón

    2006-01-01

    Das Buch Rethinking Social Inquiry, herausgegeben von Henry E. BRADY und David COLLIER, ist eine Antwort auf den Band von KING, KEOHANE und VERBA (1994), in dem versucht wird, Standards der quantitativen Forschung in der qualitativen Forschung einzuführen. Die Autoren des hier rezensierten Buchs kritisieren viele der Vorschläge, da sie argumentieren, dass qualitative Forschung anderer Werkzeuge bedürfe. Trotzdem stimmen sie zu, dass die Grundlagen des Forschungsaufbaus ähnlich sind. Das Buch ...

  10. Humanistic, authoritative and ecopsychological perspective in education or rethinking philosophy for children under globalization

    OpenAIRE

    Lushyn, Pavel; Kirovograd State Pedagogical University

    2009-01-01

    Humanistic, authoritative and ecopsychological perspective in education or rethinking philosophy for children under globalization Abstract: The paper deals with the analysis of the buffer or transitional nature of humanistic-oriented school subjects like “Philosophy for children” first introduced in the USA by Dr. M. Lipman and Dr. Ann Sharp. A new ecopsychological and ecofacilitative vision is suggested. The ecofacilitative approach is assumed to be better fit a) into the framework of...

  11. Rethinking critical reflection on care: late modern uncertainty and the implications for care ethics.

    Science.gov (United States)

    Vosman, Frans; Niemeijer, Alistair

    2017-12-01

    Care ethics as initiated by Gilligan, Held, Tronto and others (in the nineteen eighties and nineties) has from its onset been critical towards ethical concepts established in modernity, like 'autonomy', alternatively proposing to think from within relationships and to pay attention to power. In this article the question is raised whether renewal in this same critical vein is necessary and possible as late modern circumstances require rethinking the care ethical inquiry. Two late modern realities that invite to rethink care ethics are complexity and precariousness. Late modern organizations, like the general hospital, codetermined by various (control-, information-, safety-, accountability-) systems are characterized by complexity and the need for complexity reduction, both permeating care practices. By means of a heuristic use of the concept of precariousness, taken as the installment of uncertainty, it is shown that relations and power in late modern care organizations have changed, precluding the use of a straightforward domination idea of power. In the final section a proposition is made how to rethink the care ethical inquiry in order to take late modern circumstances into account: inquiry should always be related to the concerns of people and practitioners from within care practices.

  12. Auroral electron time dispersion

    International Nuclear Information System (INIS)

    Kletzing, C.A.

    1989-01-01

    A sounding rocket flight was launched from Greenland in 1985 to study high latitude, early morning auroral physics. The payload was instrumented with electron and ion detectors, AC and DC electric field experiments, a plasma density experiment, and a magnetometer to measure the ambient field. The rocket was launched during disturbed conditions, when the polar cap was in a contracted state with visible aurora overhead. The electron data contained numerous signatures indicative of time-of-flight energy dispersion characterized by a coherent structure in which lower energy electrons arrived at the rocket after higher energy electrons. A model was constructed to explain this phenomena by the sudden application of a region of parallel electric field along a length of magnetic field line above the rocket. The model incorporates detector response and uses an altitudinal density profile based on auroral zone measurements. Three types of potential structures were tried: linear, quadratic and cubic. Of the three it was found that the cubic (electric field growing in a quadratic manner moving up the field line) produced the best fit to the data. The potential region was found to be approximately 1-2 R e in extent with the lower edge 3000-4000 km away from the rocket. The background electron temperature in the model which produced the best fit to the data was of the order of 15 eV

  13. Dispersal and migration

    Directory of Open Access Journals (Sweden)

    Schwarz, C.

    2004-06-01

    Full Text Available Ringing of birds unveiled many aspects of avian migration and dispersal movements. However, there is even much more to be explored by the use of ringing and other marks. Dispersal is crucial in understanding the initial phase of migration in migrating birds as it is to understand patterns and processes of distribution and gene flow. So far, the analysis of migration was largely based on analysing spatial and temporal patters of recoveries of ringed birds. However, there are considerable biases and pitfalls in using recoveries due to spatial and temporal variation in reporting probabilities. Novel methods are required for future studies separating the confounding effects of spatial and temporal heterogeneity of recovery data and heterogeneity of the landscape as well. These novel approaches should aim a more intensive and novel use of the existing recovery data by taking advantage of, for instance, dynamic and multistate modeling, should elaborate schemes for future studies, and should also include other marks that allow a more rapid data collection, like telemetry, geolocation and global positioning systems, and chemical and molecular markers. The latter appear to be very useful in the delineating origin of birds and connectivity between breeding and non–breeding grounds. Many studies of migration are purely descriptive. However, King and Brooks (King & Brooks, 2004 examine if movement patterns of dolphins change after the introduction of a gillnet ban. Bayesian methods are an interesting approach to this problem as they provide a meaningful measure of the probability that such a change occurred rather than simple yes/no response that is often the result of classical statistical methods. However, the key difficulty of a general implementation of Bayesian methods is the complexity of the modelling —there is no general userfriendly package that is easily accessible to most scientists. Drake and Alisauskas (Drake & Alisauskas, 2004 examine the

  14. Progress in urban dispersion studies

    DEFF Research Database (Denmark)

    Batchvarova, E.; Gryning, Sven-Erik

    2006-01-01

    The present Study addresses recent achievements in better representation Of the urban area structure in meteorology and dispersion parameterisations. The setup and Main Outcome of several recent dispersion experiments in Urban areas and their use in model validation are discussed. The maximum con...

  15. Nest-mediated seed dispersal

    Science.gov (United States)

    Robert J. Warren; Jason P. Love; Mark A. Bradford

    2017-01-01

    Many plant seeds travel on the wind and through animal ingestion or adhesion; however, an overlooked dispersal mode may lurk within those dispersal modes. Viable seeds may remain attached or embedded within materials birds gather for nest building. Our objective was to determine if birds inadvertently transport seeds when they forage for plant materials to...

  16. Definition of global dispersion coefficients

    International Nuclear Information System (INIS)

    Naff, R.L.

    1983-10-01

    For estimation of a global longitudinal dispersivity at the Gorleben site, data available primarily consist of suites of geophysical logs from wells penetrating the Quaternary aquifer. A length scale for the principle aquifer at Gorleben is to be found. Samples are to be taken separately to estimate the variance in hydraulic conductivity (Taylor Analysis, Fickian dispersion process). (DG)

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

    Science.gov (United States)

    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. Wave-equation dispersion inversion

    KAUST Repository

    Li, Jing

    2016-12-08

    We present the theory for wave-equation inversion of dispersion curves, where the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. The dispersion curves are obtained from Rayleigh waves recorded by vertical-component geophones. Similar to wave-equation traveltime tomography, the complicated surface wave arrivals in traces are skeletonized as simpler data, namely the picked dispersion curves in the phase-velocity and frequency domains. Solutions to the elastic wave equation and an iterative optimization method are then used to invert these curves for 2-D or 3-D S-wave velocity models. This procedure, denoted as wave-equation dispersion inversion (WD), does not require the assumption of a layered model and is significantly less prone to the cycle-skipping problems of full waveform inversion. The synthetic and field data examples demonstrate that WD can approximately reconstruct the S-wave velocity distributions in laterally heterogeneous media if the dispersion curves can be identified and picked. The WD method is easily extended to anisotropic data and the inversion of dispersion curves associated with Love waves.

  19. Dispersion Decay and Scattering Theory

    CERN Document Server

    Komech, Alexander

    2012-01-01

    A simplified, yet rigorous treatment of scattering theory methods and their applications Dispersion Decay and Scattering Theory provides thorough, easy-to-understand guidance on the application of scattering theory methods to modern problems in mathematics, quantum physics, and mathematical physics. Introducing spectral methods with applications to dispersion time-decay and scattering theory, this book presents, for the first time, the Agmon-Jensen-Kato spectral theory for the Schr?dinger equation, extending the theory to the Klein-Gordon equation. The dispersion decay plays a crucial role i

  20. Velocity Dispersions Across Bulge Types

    International Nuclear Information System (INIS)

    Fabricius, Maximilian; Bender, Ralf; Hopp, Ulrich; Saglia, Roberto; Drory, Niv; Fisher, David

    2010-01-01

    We present first results from a long-slit spectroscopic survey of bulge kinematics in local spiral galaxies. Our optical spectra were obtained at the Hobby-Eberly Telescope with the LRS spectrograph and have a velocity resolution of 45 km/s (σ*), which allows us to resolve the velocity dispersions in the bulge regions of most objects in our sample. We find that the velocity dispersion profiles in morphological classical bulge galaxies are always centrally peaked while the velocity dispersion of morphologically disk-like bulges stays relatively flat towards the center--once strongly barred galaxies are discarded.

  1. What Causes Animals to Disperse?

    Indian Academy of Sciences (India)

    research involving animal behaviour and ecology for a very long time. ... shall examine two different types of dispersals that occur, try to understand the ... finally look at some practical methods through which the phe- ..... further qualitative or.

  2. Birefringent dispersive FDTD subgridding scheme

    OpenAIRE

    De Deckere, B; Van Londersele, Arne; De Zutter, Daniël; Vande Ginste, Dries

    2016-01-01

    A novel 2D finite difference time domain (FDTD) subgridding method is proposed, only subject to the Courant limit of the coarse grid. By making mu or epsilon inside the subgrid dispersive, unconditional stability is induced at the cost of a sparse, implicit set of update equations. By only adding dispersion along preferential directions, it is possible to dramatically reduce the rank of the matrix equation that needs to be solved.

  3. Dispersion engineering for integrated nanophotonics

    CERN Document Server

    Vanbésien, Olivier

    2014-01-01

    This book shows how dispersion engineering in two dimensional dielectric photonic crystals can provide new effects for the precise control of light propagation for integrated nanophotonics.Dispersion engineering in regular and graded photonic crystals to promote anomalous refraction effects is studied from the concepts to experimental demonstration via nanofabrication considerations. Self collimation, ultra and negative refraction, second harmonic generation, mirage and invisibility effects which lead to an unprecedented control of light propagation at the (sub-)wavelength scale for the

  4. Dispersion coefficients for coastal regions

    International Nuclear Information System (INIS)

    MacRae, B.L.; Kaleel, R.J.; Shearer, D.L.

    1983-03-01

    The Nuclear Regulatory Commission (NRC) has undertaken an extensive atmospheric dispersion research and measurement program from which it is intended will emerge improved predictive techniques for employment in licensing decisions and for emergency planning and response. Through this program the NRC has conducted field measurement programs over a wide range of geographic and topographic locations, and are using the acquired tracer and meteorological measurements to evaluate existing dispersion models and prediction techniques, and to develop new techniques when necessary

  5. (REThinking the Legal Education Through the Storytelling Practices: The Example of the Jury

    Directory of Open Access Journals (Sweden)

    Tamer Fakhoury Filho

    2016-10-01

    Full Text Available It is necessary to (rethink legal education using new methodologies. This requires changing the dominant mindset in teaching and practice of law (still essentially based on conflict and judicial proceedings. A new model can be implemented with the strategic analysis of the law and the storytelling. The storytelling in the classroom and in professional practice, is one of the viable ways to implement these changes. As the storytelling is already used in the jury, it can also be used in other professional fields and enhanced as a tool teaching of law, regardless of discipline.

  6. RETHINKING VALUE: A VALUE-CENTRIC MODEL OF PRODUCT, SERVICE AND BUSINESS DEVELOPMENT

    DEFF Research Database (Denmark)

    Randmaa, Merili; Mougaard, Krestine; Howard, Thomas J.

    2011-01-01

    Globalization and information technologies have made the economical landscape more transparent and customers smarter, more demanding and networked. Companies can see these changes as a threat to their business or as an opportunity to differentiate in the market and be a Prime Mover, by re......-thinking customer value within the value system. This article shows how the term “value” is understood in different contexts and fields of economy, to see if these definitions can be merged, in order to understand the concept of value in broader way. The authors argue through literature review and example cases...

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

    Science.gov (United States)

    Pienaar, Kiran

    2017-09-01

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

  8. The Rethinking of “the Year of Women���s Domestic Products Movement”

    OpenAIRE

    Xiaohong Zhu

    2012-01-01

    In this study, we have a research of the rethinking of “the year of Women’s Domestic Products Movement”. The “Women’s Domestic Products Movement” which was launched in 1934 has been denied by people now and before because of failing to reach the country’s intended purpose. From the angle of economic history, “Women’s Domestic Products Movement” played a positive role in promoting the domestic sales growth, reducing the index of export and import value. After carefully referring to the related...

  9. Rethinking democracy and representation: a proposal to extend the democratic canon

    Directory of Open Access Journals (Sweden)

    Alejandro Monsiváis Carrillo

    2013-01-01

    Full Text Available Rethinking political representation is necessary to understand many contemporary democratic challenges. However, a widely accepted view states that democracy and representation are two irreconcilable principles, thus hindering the theoretical assessment of political representation's democratic relevance. According to this view, what democracy needs is more popular participation; instead, representation involves elitism and political detachment. In this paper I will argue that such a view is inaccurate. Through the reconstruction of the democratic ideal, and the discussion of the concept of political representation, I intend to show that processes of political authorization, accountability and public justification are both elements of political representation and expression of democratic politics.

  10. Rethinking the Territorial Pact in the Context of European Territorial Cohesion

    Directory of Open Access Journals (Sweden)

    Irina SAGHIN

    2013-06-01

    Full Text Available The authors argue through this paper, the importance of rethinking the recently abandoned tools that can be reactivated in times of crisis. EU 2020 Strategy and other EU documents create a favorable frame in order to achieve the priorities set by reconsidering the territorial pact concept. Recent documents define the partnership agreement concept, which seems to be more rigid and less flexible than the territorial pact. Having as a starter point Romania’s specifics, there are individualized 10 thematic territorial pacts and 8 global pacts. They must generate territorial synergies capable of ensuring the coherence between regions, states and the European Union as a whole.

  11. Atmospheric dispersion of radioactive materials

    International Nuclear Information System (INIS)

    Chino, Masamichi

    1988-01-01

    The report describes currently available techniques for predicting the dispersion of accidentally released radioactive materials and techniques for visualization using computer graphics. A simulation study is also made on the dispersion of radioactive materials released from the Chernobyl plant. The simplest models include the Gauss plume model and the puff model, which cannot serve to analyze the effects of the topography, vertical wind shear, temperature inversion layer, etc. Numerical analysis methods using advection and dispersion equations are widely adopted for detailed evaluation of dispersion in an emergency. An objective analysis model or a hydrodynamical model is often used to calculate the air currents which are required to determine the advection. A small system based on the puff model is widely adopted in Europe, where the topography is considered to have only simple effects. A more sophisticated large-sized system is required in nuclear facilities located in an area with more complex topographic features. An emergency system for dispersion calculation should be equipped with a graphic display to serve for quick understanding of the radioactivity distribution. (Nogami, K.)

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

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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.…

  14. Breaking Out of the Circle: Rethinking Our Assumptions about Education and the Economy. Occasional Paper No. 2.

    Science.gov (United States)

    Berryman, Sue E.

    The National Center on Education and Employment has taken on the task of challenging and rethinking the premises that underlie traditions of human capital development in this country. This task is summarized in the question, "Who should teach which work-related skills to whom, when, and how?" Its first priority is that the Center's primary…

  15. Rethinking Teaching and Learning Pedagogy for Education in the Twenty-First Century: Blended Learning in Music Education

    Science.gov (United States)

    Crawford, Renée

    2017-01-01

    In an increasingly technologically driven world, there is proliferate discussion among education and government authorities about the necessity to rethink education in the twenty-first century. The evolution of technology and its pervasive influence on the needs and requirements of society is central to this mindset. Innovations in online…

  16. Strategies for Leading Academics to Rethink Humanities and Social Sciences Curricula in the Context of Discipline Standards

    Science.gov (United States)

    Thomas, Theda; Wallace, Joy; Allen, Pamela; Clark, Jennifer; Jones, Adrian; Lawrence, Jill; Cole, Bronwyn; Sheridan Burns, Lynette

    2017-01-01

    The introduction of discipline standards in Australia has required a comprehensive rethinking of humanities and social science curricula from first year through to graduation. This paper proposes a model to facilitate academics' engagement with discipline standards and their implication for first-year curricula. The model supports…

  17. Micromixer based on Taylor dispersion

    International Nuclear Information System (INIS)

    Yang, H; Nguyen, N-T; Huang, X

    2006-01-01

    This paper reports an analytical model, the fabrication and the characterization of a polymeric micromixer based on Taylor dispersion. Due to the distributed velocity field over the channel cross section, the effective dispersion in axial direction in a microchannel is much stronger than the pure molecular diffusion. In our work, squential segmentation was used in the micromixer for improving mixing in a microchannel. The micromixer was designed and fabricated based on lamination of five 100-μm-thick polymer sheets. Rubber valve seats were embedded between the forth and the fifth layers. The polymer layers were machined using a CO 2 laser. The lamination of the five layers was carried out by a commercial hot laminator (Aurora LM-450HC). External solenoid actuators are used for closing the valves at the mixer inlets. The experimental results confirm the effect of Taylor dispersion. Mixing ratio can be adjusted by pulse width modulation of the control signal of the solenoids

  18. Improving IUE High Dispersion Extraction

    Science.gov (United States)

    Lawton, Patricia J.; VanSteenberg, M. E.; Massa, D.

    2007-01-01

    We present a different method to extract high dispersion International Ultraviolet Explorer (IUE) spectra from the New Spectral Image Processing System (NEWSIPS) geometrically and photometrically corrected (SI HI) images of the echellogram. The new algorithm corrects many of the deficiencies that exist in the NEWSIPS high dispersion (SIHI) spectra . Specifically, it does a much better job of accounting for the overlap of the higher echelle orders, it eliminates a significant time dependency in the extracted spectra (which can be traced to the background model used in the NEWSIPS extractions), and it can extract spectra from echellogram images that are more highly distorted than the NEWSIPS extraction routines can handle. Together, these improvements yield a set of IUE high dispersion spectra whose scientific integrity is sign ificantly better than the NEWSIPS products. This work has been supported by NASA ADP grants.

  19. STELLAR MASS DEPENDENT DISK DISPERSAL

    International Nuclear Information System (INIS)

    Kennedy, Grant M.; Kenyon, Scott J.

    2009-01-01

    We use published optical spectral and infrared (IR) excess data from nine young clusters and associations to study the stellar mass dependent dispersal of circumstellar disks. All clusters older than ∼3 Myr show a decrease in disk fraction with increasing stellar mass for solar to higher mass stars. This result is significant at about the 1σ level in each cluster. For the complete set of clusters we reject the null hypothesis-that solar and intermediate-mass stars lose their disks at the same rate-with 95%-99.9% confidence. To interpret this behavior, we investigate the impact of grain growth, binary companions, and photoevaporation on the evolution of disk signatures. Changes in grain growth timescales at fixed disk temperature may explain why early-type stars with IR excesses appear to evolve faster than their later-type counterparts. Little evidence that binary companions affect disk evolution suggests that photoevaporation is the more likely mechanism for disk dispersal. A simple photoevaporation model provides a good fit to the observed disk fractions for solar and intermediate-mass stars. Although the current mass-dependent disk dispersal signal is not strong, larger and more complete samples of clusters with ages of 3-5 Myr can improve the significance and provide better tests of theoretical models. In addition, the orbits of extra-solar planets can constrain models of disk dispersal and migration. We suggest that the signature of stellar mass dependent disk dispersal due to photoevaporation may be present in the orbits of observed extra-solar planets. Planets orbiting hosts more massive than ∼1.6 M sun may have larger orbits because the disks in which they formed were dispersed before they could migrate.

  20. Dispersion of multi-walled carbon nanotubes in biocompatible dispersants

    International Nuclear Information System (INIS)

    Piret, J.-P.; Detriche, S.; Vigneron, R.; Vankoningsloo, S.; Rolin, S.; Mejia Mendoza, J. H.; Masereel, B.; Lucas, S.; Delhalle, J.; Luizi, F.; Saout, C.; Toussaint, O.

    2010-01-01

    Owing to their phenomenal electrical and mechanical properties, carbon nanotubes (CNT) have been an area of intense research since their discovery in 1991. Different applications for these nanoparticles have been proposed, among others, in electronics and optics but also in the medical field. In parallel, emerging studies have suggested potential toxic effects of CNT while others did not, generating some conflicting outcomes. These discrepancies could be, in part, due to different suspension approaches used and to the agglomeration state of CNT in solution. In this study, we described a standardized protocol to obtain stable CNT suspensions, using two biocompatible dispersants (Pluronic F108 and hydroxypropylcellulose) and to estimate the concentration of CNT in solution. CNT appear to be greatly individualized in these two dispersants with no detection of remaining bundles or agglomerates after sonication and centrifugation. Moreover, CNT remained perfectly dispersed when added to culture medium used for in vitro cell experiments. We also showed that Pluronic F108 is a better dispersant than hydroxypropylcellulose. In conclusion, we have developed a standardized protocol using biocompatible surfactants to obtain reproducible and stable multi-walled carbon nanotubes suspensions which can be used for in vitro or in vivo toxicological studies.

  1. Rethinking International Counterterrorism Assistance to the Greater Horn of Africa: Toward a Regional Risk Reduction Strategy

    Directory of Open Access Journals (Sweden)

    Matthew Schwartz

    2013-12-01

    Full Text Available The Horn of Africa has long been a recipient of foreign security assistance, with significant funds increasingly devoted to supporting subregional civilian-oriented counterterrorism efforts over the past decade. Despite efforts to better coordinate delivery, counterterrorism programming in the subregion generally remains fragmented, short-term, and siloed in implementation. This article argues that it is time to rethink the international community’s approach to counterterrorism assistance to the Horn of Africa and calls for a cohesive regional approach that not only bridges the gap between security and development, but also the gap between counterterrorism and human security. It emphasizes that the international community must not only better coordinate existing streams of counterterrorism assistance to the region, but also rethink how this assistance is designed and the ways it can be delivered to complement broader subregional development and security agendas. After a brief introduction to international counterterrorism assistance to the Horn of Africa, the article examines linkages across three thematic streams of programming being delivered to the subregion: anti-money laundering and countering the financing of terrorism; criminal justice capacity building assistance to counter terrorism; and, countering violent extremism. This discussion will highlight the need for a regional risk reduction strategy for the Horn of Africa that not only builds on the interplay of different streams of counterterrorism assistance, but on synergies across broader subregional development and security agendas as well.

  2. DIMO, a plant dispersal model

    NARCIS (Netherlands)

    Wamelink, G.W.W.; Jochem, R.; Greft, van der J.G.M.; Franke, J.; Malinowska, A.H.; Geertsema, W.; Prins, A.H.; Ozinga, W.A.; Hoek, van der D.C.J.; Grashof-Bokdam, C.J.

    2014-01-01

    Due to human activities many natural habitats have become isolated. As a result the dispersal of many plant species is hampered. Isolated populations may become extinct and have a lower probability to become reestablished in a natural way. Moreover, plant species may be forced to migrate to new

  3. A generalized advection dispersion equation

    Indian Academy of Sciences (India)

    This paper examines a possible effect of uncertainties, variability or heterogeneity of any dynamic system when being included in its evolution rule; the notion is illustrated with the advection dispersion equation, which describes the groundwater pollution model. An uncertain derivative is defined; some properties of.

  4. Ability Dispersion and Team Performance

    DEFF Research Database (Denmark)

    Hoogendoorn, Sander; Parker, Simon C.; Van Praag, Mirjam

    What is the effect of dispersed levels of cognitive ability of members of a (business) team on their team's performance? This paper reports the results of a field experiment in which 573 students in 49 teams start up and manage real companies under identical circumstances. We ensured exogenous va...

  5. Statistical description of turbulent dispersion

    NARCIS (Netherlands)

    Brouwers, J.J.H.

    2012-01-01

    We derive a comprehensive statistical model for dispersion of passive or almost passive admixture particles such as fine particulate matter, aerosols, smoke and fumes, in turbulent flow. The model rests on the Markov limit for particle velocity. It is in accordance with the asymptotic structure of

  6. Magnetic exciton dispersion in praseodymium

    DEFF Research Database (Denmark)

    Rainford, B. D.; Houmann, Jens Christian Gylden

    1971-01-01

    Measurements of the dispersion of magnetic excitons have been made in a single crystal of praseodymium metal using inelastic neutron scattering. A preliminary analysis of the data yields the first detailed information about the exchange interactions and the crystal field splittings in the light...... rare-earth metals....

  7. On Dispersion in Visual Photoreceptors

    NARCIS (Netherlands)

    Stavenga, D.G.; Barneveld, H.H. van

    1975-01-01

    An idealized visual pigment absorbance spectrum is used together with a Kramers-Kronig dispersion relation to calculate the contribution of the visual pigment to the refractive index of the fly photoreceptor. It appears that an absorption coefficient of 0.010 µm-1 results in a refractive index

  8. Dispersal in Mastomys natalensis mice

    DEFF Research Database (Denmark)

    Van Hooft, Pim; Cosson, J F; Vibe-Petersen, Solveig

    2008-01-01

    Mastomys natalensis is the major pest rodent in sub-Saharan Africa. In this study, population genetic techniques were used to gain new insights into its dispersal behaviour, a critical parameter in pest management. Using 11 microsatellites, 272 individuals from a 300 ha area in Tanzania were geno...

  9. Dispersion modeling by kinematic simulation: Cloud dispersion model

    International Nuclear Information System (INIS)

    Fung, J C H; Perkins, R J

    2008-01-01

    A new technique has been developed to compute mean and fluctuating concentrations in complex turbulent flows (tidal current near a coast and deep ocean). An initial distribution of material is discretized into any small clouds which are advected by a combination of the mean flow and large scale turbulence. The turbulence can be simulated either by kinematic simulation (KS) or direct numerical simulation. The clouds also diffuse relative to their centroids; the statistics for this are obtained from a separate calculation of the growth of individual clouds in small scale turbulence, generated by KS. The ensemble of discrete clouds is periodically re-discretized, to limit the size of the small clouds and prevent overlapping. The model is illustrated with simulations of dispersion in uniform flow, and the results are compared with analytic, steady state solutions. The aim of this study is to understand how pollutants disperses in a turbulent flow through a numerical simulation of fluid particle motion in a random flow field generated by Fourier modes. Although this homogeneous turbulent is rather a 'simple' flow, it represents a building block toward understanding pollutant dispersion in more complex flow. The results presented here are preliminary in nature, but we expect that similar qualitative results should be observed in a genuine turbulent flow.

  10. UV curable aqueous dispersions for wood coatings

    International Nuclear Information System (INIS)

    Peeters, S.; Bleus, J.P.; Wang, Z.J.; Arceneaux, J. A.; Hall, J.

    1999-01-01

    In this paper the characterisation of aqueous dispersions of UV curable resins is described. Two types of dispersions were used: dispersions that are tacky after water evaporation and tack - free before cure dispersions. The physical and rheological properties of these products have been determined and the performance of these dispersions in various formulations, especially for wood applications has been studied. With these dispersions, it is possible to produce coatings having a good cure speed, good surface hardness and good solvent -, chemical - and water resistance

  11. Laser control of natural disperse systems

    Science.gov (United States)

    Vlasova, Olga L.; Bezrukova, Alexandra G.

    2003-10-01

    Different water disperse systems were studied by integral (spectroturbidemetry) and differential light scattering method with a laser as a source of light. The investigation done concerns the state of kaolin dispersions at storage and under dilution as an example of mineral dispersion systems such as natural water. The role of some light scattering parameters for an optical analysis of water dispersions, like the dispersion of erythrocytes and bacterial cells -Escherichia coli is discussed. The results obtained can help to elaborate the methods for on-line optical control fo natural disperse systems (water, air) with mineral and biological particles.

  12. Nanocomposites from Stable Dispersions of Carbon Nanotubes in Polymeric Matrices Using Dispersion Interaction

    Science.gov (United States)

    Wise, Kristopher Eric (Inventor); Park, Cheol (Inventor); Kang, Jin Ho (Inventor); Siochi, Emilie J. (Inventor); Harrison, Joycelyn S. (Inventor)

    2016-01-01

    Stable dispersions of carbon nanotubes (CNTs) in polymeric matrices include CNTs dispersed in a host polymer or copolymer whose monomers have delocalized electron orbitals, so that a dispersion interaction results between the host polymer or copolymer and the CNTs dispersed therein. Nanocomposite products, which are presented in bulk, or when fabricated as a film, fiber, foam, coating, adhesive, paste, or molding, are prepared by standard means from the present stable dispersions of CNTs in polymeric matrices, employing dispersion interactions, as presented hereinabove.

  13. Transverse dispersion in heterogeneous fractures

    International Nuclear Information System (INIS)

    Dershowitz, Bill; Shuttle, Dawn; Klise, Kate; Outters, Nils; Hermanson, Jan

    2004-12-01

    This report evaluates the significance of transverse dispersion processes for solute transport in a single fracture. Transverse dispersion is a potentially significant process because it increases the fracture surface area available for sorptive and diffusive properties, and has the potential to transport solute between what would otherwise be distinctive, streamline pathways. Transverse dispersion processes are generally ignored in one-dimensional repository performance assessment approaches. This report provides an initial assessment of the magnitude of transverse dispersion effect in a single heterogeneous fracture on repository safety assessment. This study builds on a previous report which considered the network effects on transport dispersion including streamline routing and mixing at fracture intersections. The project uses FracMan software. This platform has been extensively used by SKB in other projects. FracMan software is designed to generate and analyze DFN's as well as to compute fluid flow in DFN's with the MAFIC Finite element method (FEM) code. Solute transport was modeled using the particle tracking inside MAFIC, the 2-D Laplace Transform Galerkin inside PAWorks/LTG, and the 1-D Laplace Transform approach designed to replicate FARF31 inside GoldSim.The study reported here focuses on a single, 20-meter scale discrete fracture, with simplified boundary conditions intended to represent the position of this fracture within a fracture network. The range of assumptions made regarding fracture heterogeneity were as follows: Base case, Heterogeneous fracture, geostatistical field, correlation length 0.01 m. Case 1a, Homogeneous fracture, transmissivity = 10 -7 m 2 /s. Case 1b, Heterogeneous fracture, non-channeled geostatistical field correlation length 5 m. Case 1c, Heterogeneous fracture, channeled, anisotropic geostatistical field. Case 1d, Heterogeneous fracture, fracture intersection zone (FIZ) permeability enhanced. Case 5, Simple channelized

  14. Procedure for preparation of dispersions

    International Nuclear Information System (INIS)

    1978-01-01

    Procedure for the preparation of a water based dispersion of cerium oxide, characterised in that a suspension of cerium (IV) hydroxide is formed with an acid, where the acid is in the state of a disaggregation of aggregated crystalline cerium hydroxide, the suspension being preheated for a specified time and to a specified temperature, so that the pH value becomes constant, and whereby the quantity of acid in the suspension is such that the constant pH value is lower than 5.4, so that a conditioned suspension may be obtained, and water may be mixed with the conditioned suspension for making a water based dispersion of cerium oxide. (G.C.)

  15. Stochastic models for atmospheric dispersion

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager

    2003-01-01

    Simple stochastic differential equation models have been applied by several researchers to describe the dispersion of tracer particles in the planetary atmospheric boundary layer and to form the basis for computer simulations of particle paths. To obtain the drift coefficient, empirical vertical...... positions close to the boundaries. Different rules have been suggested in the literature with justifications based on simulation studies. Herein the relevant stochastic differential equation model is formulated in a particular way. The formulation is based on the marginal transformation of the position...... velocity distributions that depend on height above the ground both with respect to standard deviation and skewness are substituted into the stationary Fokker/Planck equation. The particle position distribution is taken to be uniform *the well/mixed condition( and also a given dispersion coefficient...

  16. Ability Dispersion and Team Performance

    DEFF Research Database (Denmark)

    Hoogendoorn, Sander; Parker, Simon C.; Van Praag, Mirjam

    What is the effect of dispersed levels of cognitive ability of members of a (business) team on their team's performance? This paper reports the results of a field experiment in which 573 students in 49 (student) teams start up and manage real companies under identical circumstances for one year. We...... ensured exogenous variation in otherwise random team composition by assigning students to teams based on their measured cognitive abilities. Each team performs a variety of tasks, often involving complex decision making. The key result of the experiment is that the performance of business teams first...... increases and then decreases with ability dispersion. We seek to understand this finding by developing a model in which team members of different ability levels form sub- teams with other team members with similar ability levels to specialize in different productive tasks. Diversity spreads production over...

  17. Magnetic effects in anomalous dispersion

    International Nuclear Information System (INIS)

    Blume, M.

    1992-01-01

    Spectacular enhancements of magnetic x-ray scattering have been predicted and observed experimentally. These effects are the result of resonant phenomena closely related to anomalous dispersion, and they are strongest at near-edge resonances. The theory of these resonances will be developed with particular attention to the symmetry properties of the scatterer. While the phenomena to be discussed concern magnetic properties the transitions are electric dipole or electric quadrupole in character and represent a subset of the usual anomalous dispersion phenomena. The polarization dependence of the scattering is also considered, and the polarization dependence for magnetic effects is related to that for charge scattering and to Templeton type anisotropic polarization phenomena. It has been found that the strongest effects occur in rare-earths and in actinides for M shell edges. In addition to the scattering properties the theory is applicable to ''forward scattering'' properties such as the Faraday effect and circular dichroism

  18. Faraday anomalous dispersion optical tuners

    Science.gov (United States)

    Wanninger, P.; Valdez, E. C.; Shay, T. M.

    1992-01-01

    Common methods for frequency stabilizing diode lasers systems employ gratings, etalons, optical electric double feedback, atomic resonance, and a Faraday cell with low magnetic field. Our method, the Faraday Anomalous Dispersion Optical Transmitter (FADOT) laser locking, is much simpler than other schemes. The FADOT uses commercial laser diodes with no antireflection coatings, an atomic Faraday cell with a single polarizer, and an output coupler to form a compound cavity. This method is vibration insensitive, thermal expansion effects are minimal, and the system has a frequency pull in range of 443.2 GHz (9A). Our technique is based on the Faraday anomalous dispersion optical filter. This method has potential applications in optical communication, remote sensing, and pumping laser excited optical filters. We present the first theoretical model for the FADOT and compare the calculations to our experimental results.

  19. Dispersed Fringe Sensing Analysis - DFSA

    Science.gov (United States)

    Sigrist, Norbert; Shi, Fang; Redding, David C.; Basinger, Scott A.; Ohara, Catherine M.; Seo, Byoung-Joon; Bikkannavar, Siddarayappa A.; Spechler, Joshua A.

    2012-01-01

    Dispersed Fringe Sensing (DFS) is a technique for measuring and phasing segmented telescope mirrors using a dispersed broadband light image. DFS is capable of breaking the monochromatic light ambiguity, measuring absolute piston errors between segments of large segmented primary mirrors to tens of nanometers accuracy over a range of 100 micrometers or more. The DFSA software tool analyzes DFS images to extract DFS encoded segment piston errors, which can be used to measure piston distances between primary mirror segments of ground and space telescopes. This information is necessary to control mirror segments to establish a smooth, continuous primary figure needed to achieve high optical quality. The DFSA tool is versatile, allowing precise piston measurements from a variety of different optical configurations. DFSA technology may be used for measuring wavefront pistons from sub-apertures defined by adjacent segments (such as Keck Telescope), or from separated sub-apertures used for testing large optical systems (such as sub-aperture wavefront testing for large primary mirrors using auto-collimating flats). An experimental demonstration of the coarse-phasing technology with verification of DFSA was performed at the Keck Telescope. DFSA includes image processing, wavelength and source spectral calibration, fringe extraction line determination, dispersed fringe analysis, and wavefront piston sign determination. The code is robust against internal optical system aberrations and against spectral variations of the source. In addition to the DFSA tool, the software package contains a simple but sophisticated MATLAB model to generate dispersed fringe images of optical system configurations in order to quickly estimate the coarse phasing performance given the optical and operational design requirements. Combining MATLAB (a high-level language and interactive environment developed by MathWorks), MACOS (JPL s software package for Modeling and Analysis for Controlled Optical

  20. Hydrodynamic dispersion within porous biofilms

    KAUST Repository

    Davit, Y.

    2013-01-23

    Many microorganisms live within surface-associated consortia, termed biofilms, that can form intricate porous structures interspersed with a network of fluid channels. In such systems, transport phenomena, including flow and advection, regulate various aspects of cell behavior by controlling nutrient supply, evacuation of waste products, and permeation of antimicrobial agents. This study presents multiscale analysis of solute transport in these porous biofilms. We start our analysis with a channel-scale description of mass transport and use the method of volume averaging to derive a set of homogenized equations at the biofilm-scale in the case where the width of the channels is significantly smaller than the thickness of the biofilm. We show that solute transport may be described via two coupled partial differential equations or telegrapher\\'s equations for the averaged concentrations. These models are particularly relevant for chemicals, such as some antimicrobial agents, that penetrate cell clusters very slowly. In most cases, especially for nutrients, solute penetration is faster, and transport can be described via an advection-dispersion equation. In this simpler case, the effective diffusion is characterized by a second-order tensor whose components depend on (1) the topology of the channels\\' network; (2) the solute\\'s diffusion coefficients in the fluid and the cell clusters; (3) hydrodynamic dispersion effects; and (4) an additional dispersion term intrinsic to the two-phase configuration. Although solute transport in biofilms is commonly thought to be diffusion dominated, this analysis shows that hydrodynamic dispersion effects may significantly contribute to transport. © 2013 American Physical Society.

  1. Dispersion of Bed Load Particles

    OpenAIRE

    SAWAI, Kenji

    1987-01-01

    The motion of bed load particles is so irregular that they disperse remarkably with time.In this study, some flume tests using painted tracer particles were carried out, in which thedispersive property of tracers changed variously with sediment feed rate.In analysing this process, a stochastic simulation model is proposed where it is discussedabout the degree of exposure of individual particle near the bed surface and about the variationof its pick up rate. The exponential distribution of ste...

  2. Faraday anomalous dispersion optical filters

    Science.gov (United States)

    Shay, T. M.; Yin, B.; Alvarez, L. S.

    1993-01-01

    The effect of Faraday anomalous dispersion optical filters on infrared and blue transitions of some alkali atoms is calculated. A composite system is designed to further increase the background noise rejection. The measured results of the solar background rejection and image quality through the filter are presented. The results show that the filter may provide high transmission and high background noise rejection with excellent image quality.

  3. Dispersive stresses in wind farms

    Science.gov (United States)

    Segalini, Antonio; Braunbehrens, Robert; Hyvarinen, Ann

    2017-11-01

    One of the most famous models of wind farms is provided by the assumption that the farm can be approximated as a horizontally-homogeneous forest canopy with vertically-varying force intensity. By means of this approximation, the flow-motion equations become drastically simpler, as many of the three-dimensional effects are gone. However, the application of the horizontal average operator to the RANS equations leads to the appearance of new transport terms (called dispersive stresses) originating from the horizontal (small-scale) variation of the mean velocity field. Since these terms are related to the individual turbine signature, they are expected to vanish outside the roughness sublayer, providing a definition for the latter. In the present work, an assessment of the dispersive stresses is performed by means of a wake-model approach and through the linearised code ORFEUS developed at KTH. Both approaches are very fast and enable the characterization of a large number of wind-farm layouts. The dispersive stress tensor and its effect on the turbulence closure models are investigated, providing guidelines for those simulations where it is impossible to resolve the farm at a turbine scale due to grid requirements (as, for instance, mesoscale simulations).

  4. Improving practical atmospheric dispersion models

    International Nuclear Information System (INIS)

    Hunt, J.C.R.; Hudson, B.; Thomson, D.J.

    1992-01-01

    The new generation of practical atmospheric dispersion model (for short range ≤ 30 km) are based on dispersion science and boundary layer meteorology which have widespread international acceptance. In addition, recent improvements in computer skills and the widespread availability of small powerful computers make it possible to have new regulatory models which are more complex than the previous generation which were based on charts and simple formulae. This paper describes the basis of these models and how they have developed. Such models are needed to satisfy the urgent public demand for sound, justifiable and consistent environmental decisions. For example, it is preferable that the same models are used to simulate dispersion in different industries; in many countries at present different models are used for emissions from nuclear and fossil fuel power stations. The models should not be so simple as to be suspect but neither should they be too complex for widespread use; for example, at public inquiries in Germany, where simple models are mandatory, it is becoming usual to cite the results from highly complex computational models because the simple models are not credible. This paper is written in a schematic style with an emphasis on tables and diagrams. (au) (22 refs.)

  5. Dispersion relations in loop calculations

    International Nuclear Information System (INIS)

    Kniehl, B.A.

    1996-01-01

    These lecture notes give a pedagogical introduction to the use of dispersion relations in loop calculations. We first derive dispersion relations which allow us to recover the real part of a physical amplitude from the knowledge of its absorptive part along the branch cut. In perturbative calculations, the latter may be constructed by means of Cutkosky's rule, which is briefly discussed. For illustration, we apply this procedure at one loop to the photon vacuum-polarization function induced by leptons as well as to the γf anti-f vertex form factor generated by the exchange of a massive vector boson between the two fermion legs. We also show how the hadronic contribution to the photon vacuum polarization may be extracted from the total cross section of hadron production in e + e - annihilation measured as a function of energy. Finally, we outline the application of dispersive techniques at the two-loop level, considering as an example the bosonic decay width of a high-mass Higgs boson. (author)

  6. Chromatic Dispersion Estimation in Digital Coherent Receivers

    DEFF Research Database (Denmark)

    Soriano, Ruben Andres; Hauske, Fabian N.; Guerrero Gonzalez, Neil

    2011-01-01

    Polarization-diverse coherent demodulation allows to compensate large values of accumulated linear distortion by digital signal processing. In particular, in uncompensated links without optical dispersion compensation, the parameter of the residual chromatic dispersion (CD) is vital to set...

  7. Statistical Physics of Colloidal Dispersions.

    Science.gov (United States)

    Canessa, E.

    Available from UMI in association with The British Library. Requires signed TDF. This thesis is concerned with the equilibrium statistical mechanics of colloidal dispersions which represent useful model systems for the study of condensed matter physics; namely, charge stabilized colloidal dispersions and polymer stabilized colloidal dispersions. A one-component macroparticle approach is adopted in order to treat the macroscopic and microscopic properties of these systems in a simple and comprehensive manner. The thesis opens with the description of the nature of the colloidal state before reviewing some basic definitions and theory in Chapter II. In Chapter III a variational theory of phase equilibria based on the Gibbs-Bogolyobov inequality is applied to sterically stabilized colloidal dispersions. Hard spheres are chosen as the reference system for the disordered phases while an Einstein model is used for the ordered phases. The new choice of pair potential, taken for mathematical convenience, is a superposition of two Yukawa functions. By matching a double Yukawa potential to the van der Waals attractive potential at different temperatures and introducing a purely temperature dependent coefficient to the repulsive part, a rich variety of observed phase separation phenomena is qualitatively described. The behaviour of the potential is found to be consistent with a small decrease of the polymer layer thickness with increasing temperature. Using the same concept of a collapse transition the non-monotonic second virial coefficient is also explained and quantified. It is shown that a reduction of the effective macroparticle diameter with increasing temperature can only be partially examined from the point of view of a (binary-) polymer solution theory. This chapter concludes with the description of the observed, reversible, depletion flocculation behaviour. This is accomplished by using the variational formalism and by invoking the double Yukawa potential to allow

  8. Rethinking urban nature to promote human well-being and livelihoods

    DEFF Research Database (Denmark)

    Raymond, Christopher; Gulsrud, Natalie Marie; Rodela, Romina

    On the 25thJanuary, 25 researchers, social entrepreneurs and policy makers attended a MOVIUM and SLU Urban Futures funded workshop on “Rethinking urban nature to promote human well-being and livelihoods”. The objectives of the workshop wereto identify and discuss integrated digital, social...... of urbannature in Malmö. Each group was asked to present their presentation to the wider group, what inspired them the most from the workshop activity and how their understanding of integrated solutions in urban nature changed over the day.This report presents a summary of each group’screations and findings...... and nature solutions for the use, management and governance of urban nature in the City of Malmö;and to provide a platform for knowledge sharing and networking between researchers and practitioners.Multiple enlightening presentations on how to plan, design and manage urban nature were provided by the cities...

  9. Refusing to be Complicit in our Prison Nation: Teachers Rethinking Mandated Reporting

    Directory of Open Access Journals (Sweden)

    Erica Meiners

    2016-11-01

    Full Text Available Ensuring that Black Lives Matter in schools requires seismic shifts including excavating the ongoing practices and policies that reproduce heterogendered white supremacy in schools. However, what is too often erased in these movements is the key way the profession of teaching facilitates racialized surveillance and criminalization. Teachers are mandated reporters who are required by law to report suspected negligence and abuse. While on paper this charge looks neutral, this essay illustrates why teachers should rethink their roles and organize against mandated reporting laws. To teach to ensure that all Black Lives Matter requires refusing to be complicit in the mechanisms that contribute to the destruction of too many families and communities.

  10. Rethinking central concepts of work and travel in the "age of aeromobility"

    DEFF Research Database (Denmark)

    Lassen, Claus

    2004-01-01

    between work and tourism is not distinct and there is a very complex connection between travel, work, tourism and play. It shows that actually, there is a strong ?material? impact from supposedly ?immaterial? organisations and this ?materiality? is particularly linked to the extension of forms of mobility......In this article, the hypothesis is that there is a connection between international aeromobility, knowledge organisations and environmental impacts. The object is therefore to examine the driving forces, mechanisms and patterns of meaning behind the increase in international long distance work......-mobility. The article will draw on a case study which involves two Danish examples of ?knowledge organisations?. It argues that it is necessary to rethink central concepts of travel, tourism and working life, in order to understand and describe this kind of international mobility in these organisations. The boundary...

  11. Health access and medical care as socio-political vindications. Rethinking global health from the margins

    Directory of Open Access Journals (Sweden)

    Néstor Nuño Martínez

    2017-06-01

    Full Text Available According to the exigencies of national and international institutions, non-governmental and grassroots organizations assisting waria —male-to-female transvestites— in the Indonesian city of Jogjakarta have focused all their programs in the prevention and treatment of HIV. As a result of a recent training program in social management, groups of waria have decided to establish themselves as independent institutions and initiate socio-political processes of revindication and negotiation aimed at obtaining free medical access and care. Throughout analysing the underlying causes that have motivated these practices and their consequences, this paper seeks to discuss and rethink the prevailing priorities constructed in global health —characterized by presenting the battle against HIV and Malaria as a the pressing health priorities in the Global South.

  12. Rethinking Conventional Teaching In Language Learning And Proposing Edmodo As Intervention: A Qualitative Analysis

    Directory of Open Access Journals (Sweden)

    Farha Alia Mokhtar

    2016-04-01

    Full Text Available In recent times, educators are urged to transform the techniques in conducting language learning by incorporating technological tools because new technologies stimulate an explosion of new methods for teaching and learning. This article emphasizes the conventional teaching pedagogy and the urgency to rethink its practice in language learning while proposing a possible platform for learners’ and teachers’ needs. I outline the perceptions of future teachers on conventional teaching, shifting of teaching style from conventional to digital designs and the possibility of implementing Edmodo to curb the concerns arising. The argumentset forward isregarding conventional teaching that hinders potentials of students, followed by participants’ hopes for teaching approaches and the likelihood of implementing Edmodo to assist in the language learning classroom with grammar, vocabulary, self‐efficacy and target language and practice.  

  13. Review: Henry E. Brady & David Collier (Eds. (2004. Rethinking Social Inquiry: Diverse Tools, Shared Standards

    Directory of Open Access Journals (Sweden)

    Matthias Catón

    2006-03-01

    Full Text Available The book Rethinking Social Inquiry, edited by Henry E. BRADY and David COLLIER, is a response to a book by KING, KEOHANE and VERBA (1994 that aimed to introduce quantitative standards to qualitative research. The authors of the book reviewed here criticize many of the suggestions made there because they argue that qualitative research requires other tools. Nevertheless, they agree that the foundations of research design are similar. The book comprises a comprehensive critique of mainstream quantitative techniques, describes a set of qualitative tools for research, and addresses issues of how to combine qualitative and quantitative approaches to maximize analytical leverage. It is an excellent contribution to the methodological debate in the social sciences. URN: urn:nbn:de:0114-fqs0602309

  14. Rethinking Social Work in times of economic and financial crisis in Portugal

    Directory of Open Access Journals (Sweden)

    Maria-Irene Carvalho

    2017-06-01

    Full Text Available The purpose of this paper is to contextualize the social policy transformations in social services and health care system in the context of the economic and financial crisis and following intervention of the international monetary fund, the World Bank and the European Central Bank (Troika in Portugal, over the past four years. We analyze the social emergency program, which replaced the national plan for social inclusion, and the implementation of the national integrated network for long term care. Based on the evidence of the results we reflect on these transformations in Social Work, highlighting the negative aspects and the challenges for this profession. To achieve these aims we analyzed documents, statistical data and research on this subject. In this context of scarcity and emergency interventions, Social Work is challenged to rethink itself as a sociopolitical profession, taking into account the temporality of the intervention, the allocation of resources and the training of professionals.

  15. Rethinking Value in the Bio-economy: Finance, Assetization, and the Management of Value.

    Science.gov (United States)

    Birch, Kean

    2017-05-01

    Current debates in science and technology studies emphasize that the bio-economy-or, the articulation of capitalism and biotechnology-is built on notions of commodity production, commodification, and materiality, emphasizing that it is possible to derive value from body parts, molecular and cellular tissues, biological processes, and so on. What is missing from these perspectives, however, is consideration of the political-economic actors, knowledges, and practices involved in the creation and management of value. As part of a rethinking of value in the bio-economy, this article analyzes three key political-economic processes: financialization, capitalization, and assetization. In doing so, it argues that value is managed as part of a series of valuation practices, it is not inherent in biological materialities.

  16. Rethinking of the criteria for natural analogue study. A case of Tono natural analogue study

    International Nuclear Information System (INIS)

    Yoshida, Hidekazu

    1996-01-01

    Natural analogue regarding long-term performance of the geological disposal system for radioactive waste isolation is essentially the study of geochemical process which has been evolved in geological environment. All geochemical studies, however, will not be nominated as natural analogue studies. It is, therefore, important to be clear the criteria for natural analogue study with the view of analogy by following three categories, (1) Conceptual model development, (2) Data provision and (3) Model testing, for the concept of geological disposal and safety assessment model. Rethinking of the criteria for natural analogue study through the case of Tono Natural Analogue Study, and the usefulness of natural analogue study for the safety assessment of geological disposal system in Japan have been presented in this paper. (author)

  17. Rethinking project portfolio management: A case study of a public organization

    DEFF Research Database (Denmark)

    Hansen, Lars Kristian; Svejvig, Per

    2018-01-01

    analytical perspectives. One perspective, denoted as classical project management (CPM), highlights key characteristics of traditional PPM research. A second perspective, denoted as rethinking project management (RPM), highlights characteristics of progressive PPM research. Against this background, we...... diagnose PPM practices in a large public organization and find that organizational top management use the vocabulary and request the values emphasized by the CPM perspective, such as executability, controllability, instrumentality and linearity. However, below top management level, we find managers...... practices. Taking into account the limitations of our single case study design, our research shows how an organization, which differs considerably from advise provided by the conventional CPM perspective, and best PPM practices, may be well functioning – or at least, in large, meets the organization’ PPM...

  18. Rethinking Suffering: Allowing for Suffering that is Intrinsic at End of Life.

    Science.gov (United States)

    Rattner, Maxxine; Berzoff, Joan

    2016-01-01

    The dilemma so central to the work of providers of palliative and end-of-life care is the paradox of their professional and ethical duty to try to relieve suffering and the limitations of so doing. While the capacity to sit with suffering at the end of life is critical to clinical work, the idea that some intrinsic suffering cannot necessarily always be relieved may model for patients and families that suffering can be borne. Clinicians who encounter unrelievable suffering may feel a sense of failure, helplessness, moral distress, and compassion fatigue. While tolerating suffering runs counter to the aims of palliative care, acknowledging it, bearing it, and validating it may actually help patients and families to do the same. "Sitting with suffering" signals a paradigm shift within the discipline of palliative care, as it asks clinicians to rethink their role in being able to relieve some forms of psychosocial suffering intrinsic to dying.

  19. Dispersion properties of photonic crystal fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Dridi, Kim

    1998-01-01

    Approximate dispersion and bending properties of all-silica two-dimensional photonic crystal fibres are characterised by the combination of an effective-index model and classical analysis tools for optical fibres. We believe for the first time to have predicted the dispersion properties of photonic...... crystal fibres. The results strongly indicate that these fibres have potential applications as dispersion managing components...

  20. Catchment Dispersion Mechanisms in an Urban Context

    Science.gov (United States)

    Gironas, J. A.; Mejia, A.; Rossel, F.; Rinaldo, A.; Rodriguez, F.

    2014-12-01

    Dispersion mechanisms have been examined in-depth in natural catchments in previous studies. However, these dispersion mechanisms have been studied little in urban catchments, where artificial transport elements and morphological arrangements are expected to modify travel times and mobilize excess rainfall from spatially distributed impervious sites. Thus, these features can modify the variance of the catchment's travel times and hence the total dispersion. This work quantifies the dispersion mechanisms in an urban catchment using the theory of transport by travel times as represented by the Urban Morpho-climatic Instantaneous Unit Hydrograph (U-McIUH) model. This model computes travel times based on kinematic wave theory and accounts explicitly for the path heterogeneities and altered connectivity patterns characteristic of an urban drainage network. The analysis is illustrated using the Aubinière urban catchment (France) as a case study. We found that kinematic dispersion is dominant for small rainfall intensities, whereas geomorphologic dispersion becomes more dominant for larger intensities. The total dispersion scales with the drainage area in a power law fashion. The kinematic dispersion is dominant across spatial scales up to a threshold of approximately 2-3 km2, after which the geomorphologic dispersion becomes more dominant. Overall, overland flow is responsible for most of the dispersion, while conduits tend to counteract the increase of the geomorphologic dispersion with a negative kinematic dispersion. Further studies with other catchments are needed to assess whether the latter is a general feature of urban drainage networks.

  1. Dispersion of coupled mode-gap cavities

    NARCIS (Netherlands)

    Lian, Jin; Sokolov, Sergei; Yuce, E.; Combrie, S.; de Rossi, A.; Mosk, Allard

    2015-01-01

    The dispersion of a coupled resonator optical waveguide made of photonic crystal mode-gap cavities is pronouncedly asymmetric. This asymmetry cannot be explained by the standard tight binding model. We show that the fundamental cause of the asymmetric dispersion is the inherent dispersive cavity

  2. Characterization of finite spaces having dispersion points

    International Nuclear Information System (INIS)

    Al-Bsoul, A. T

    1997-01-01

    In this paper we shall characterize the finite spaces having dispersion points. Also, we prove that the dispersion point of a finite space with a dispersion points fixed under all non constant continuous functions which answers the question raised by J. C obb and W. Voxman in 1980 affirmatively for finite space. Some open problems are given. (author). 16 refs

  3. A quale ruolo “adulto” formerà la scuola? Riflessioni a par- tire dalla strategia europea Rethinking Education

    Directory of Open Access Journals (Sweden)

    Elena Marescotti

    2014-04-01

    Full Text Available This paper focuses on the European Commission Communication Rethinking Education: Investing in skills for better socio-economic outcomes (November 2012. The comments concern the school educational tasks and, in particular, the young-adult “identity” required to face multiple challenges of current global crisis. In an educational perspective, it require a "re-thinking" of education, maintaining a meaning horizon dedicated to the promotion of a "genuine" quality of life, and an anthropological project that cannot be sacrificed in the name of the contingent political and economic pressures. In a lifelong education view, this article considers the relationship between education/adult education and the meaning of adult identity, to improve the human "desirable" ideals vs than what is too often presented as “necessary evil”.

  4. Corporate Social Capital and Public Relations : Capital Accumulation by Social Relationship and Rethinking the Definition of Public Relations

    OpenAIRE

    北見, 幸一

    2009-01-01

    This paper discusses Corporate Social Capital and Public Relations. This paper overviewed the Social Capital studies, especially early studies in sociology field, proposed the framework to evaluate Social Capital in a capital. Social Capital has the merit to reduce transaction costs, and should be clearly positioned as a component of capital of corporation. Using the concept of the Corporate Social Capital, to rethink the definition of Public Relations, this paper proposed the following defin...

  5. Normal-dispersion microresonator Kerr frequency combs

    Directory of Open Access Journals (Sweden)

    Xue Xiaoxiao

    2016-06-01

    Full Text Available Optical microresonator-based Kerr frequency comb generation has developed into a hot research area in the past decade. Microresonator combs are promising for portable applications due to their potential for chip-level integration and low power consumption. According to the group velocity dispersion of the microresonator employed, research in this field may be classified into two categories: the anomalous dispersion regime and the normal dispersion regime. In this paper, we discuss the physics of Kerr comb generation in the normal dispersion regime and review recent experimental advances. The potential advantages and future directions of normal dispersion combs are also discussed.

  6. Dispersed publication of editorial research

    DEFF Research Database (Denmark)

    Rosenberg, Jacob; Pommergaard, Hans-Christian; Vinther, Siri

    2015-01-01

    INTRODUCTION: There seems to be no dedicated journals available for publication of editorial research in the biomedical sciences; that is research into editorial or publication process issues involving the scientific approach to writing, reviewing, editing and publishing. It is unknown where papers...... journals with a median of one article per journal (range: 1-17). CONCLUSION: The publication of papers on editorial research seems to be dispersed. In order to increase the visibility of this research field, it may be reasonable to establish well-defined platforms such as dedicated journals or journal...

  7. A nonlocal inhomogeneous dispersal process

    Science.gov (United States)

    Cortázar, C.; Coville, J.; Elgueta, M.; Martínez, S.

    This article in devoted to the study of the nonlocal dispersal equation u(x,t)=∫R J({x-y}/{g(y)}){u(y,t)}/{g(y)} dy-u(x,t) in R×[0,∞), and its stationary counterpart. We prove global existence for the initial value problem, and under suitable hypothesis on g and J, we prove that positive bounded stationary solutions exist. We also analyze the asymptotic behavior of the finite mass solutions as t→∞, showing that they converge locally to zero.

  8. Taylor dispersion on a fractal

    International Nuclear Information System (INIS)

    Mazo, R.M.

    1998-01-01

    Taylor dispersion is the greatly enhanced diffusion in the direction of a fluid flow caused by ordinary diffusion in directions orthogonal to the flow. It is essential that the system be bounded in space in the directions orthogonal to the flow. We investigate the situation where the medium through which the flow occurs has fractal properties so that diffusion in the orthogonal directions is anomalous and non-Fickian. The effective diffusion in the flow direction remains normal; its width grows proportionally with the time. However, the proportionality constant depends on the fractal dimension of the medium as well as its walk dimension. (author)

  9. Extragalactic dispersion measures of fast radio bursts

    International Nuclear Information System (INIS)

    Xu, Jun; Han, J. L.

    2015-01-01

    Fast radio bursts show large dispersion measures, much larger than the Galactic dispersion measure foreground. Therefore, they evidently have an extragalactic origin. We investigate possible contributions to the dispersion measure from host galaxies. We simulate the spatial distribution of fast radio bursts and calculate the dispersion measures along the sightlines from fast radio bursts to the edge of host galaxies by using the scaled NE2001 model for thermal electron density distributions. We find that contributions to the dispersion measure of fast radio bursts from the host galaxy follow a skew Gaussian distribution. The peak and the width at half maximum of the dispersion measure distribution increase with the inclination angle of a spiral galaxy, to large values when the inclination angle is over 70°. The largest dispersion measure produced by an edge-on spiral galaxy can reach a few thousand pc cm −3 , while the dispersion measures from dwarf galaxies and elliptical galaxies have a maximum of only a few tens of pc cm −3 . Notice, however, that additional dispersion measures of tens to hundreds of pc cm −3 can be produced by high density clumps in host galaxies. Simulations that include dispersion measure contributions from the Large Magellanic Cloud and the Andromeda Galaxy are shown as examples to demonstrate how to extract the dispersion measure from the intergalactic medium. (paper)

  10. Introduction to nonlinear dispersive equations

    CERN Document Server

    Linares, Felipe

    2015-01-01

    This textbook introduces the well-posedness theory for initial-value problems of nonlinear, dispersive partial differential equations, with special focus on two key models, the Korteweg–de Vries equation and the nonlinear Schrödinger equation. A concise and self-contained treatment of background material (the Fourier transform, interpolation theory, Sobolev spaces, and the linear Schrödinger equation) prepares the reader to understand the main topics covered: the initial-value problem for the nonlinear Schrödinger equation and the generalized Korteweg–de Vries equation, properties of their solutions, and a survey of general classes of nonlinear dispersive equations of physical and mathematical significance. Each chapter ends with an expert account of recent developments and open problems, as well as exercises. The final chapter gives a detailed exposition of local well-posedness for the nonlinear Schrödinger equation, taking the reader to the forefront of recent research. The second edition of Introdu...

  11. Dispersivity in heterogeneous permeable media

    International Nuclear Information System (INIS)

    Chesnut, D.A.

    1994-01-01

    When one fluid displaces another through a one-dimensional porous medium, the composition changes from pure displacing fluid at the inlet to pure displaced fluid some distance downstream. The distance over which an arbitrary percentage of this change occurs is defined as the mixing zone length, which increases with increasing average distance traveled by the displacement front. For continuous injection, the mixing zone size can be determined from a breakthrough curve as the time required for the effluent displacing fluid concentration to change from, say, 10% to 90%. In classical dispersion theory, the mixing zone grows in proportion to the square root of the mean distance traveled, or, equivalently, to the square root of the mean breakthrough time. In a multi-dimensional heterogeneous medium, especially at field scales, the size of the mixing zone grows almost linearly with mean distance or travel time. If an observed breakthrough curve is forced to fit the, clinical theory, the resulting effective dispersivity, instead of being constant, also increases almost linearly with the spatial or temporal scale of the problem. This occurs because the heterogeneity in flow properties creates a corresponding velocity distribution along the different flow pathways from the inlet to the outlet of the system. Mixing occurs mostly at the outlet, or wherever the fluid is sampled, rather than within the medium. In this paper, we consider the effects. of this behavior on radionuclide or other contaminant migration

  12. Dispersivity in heterogeneous permeable media

    International Nuclear Information System (INIS)

    Chesnut, D.A.

    1994-01-01

    When one fluid displaces another through a one-dimensional porous medium, the composition changes from pure displacing fluid at the inlet to pure displaced fluid some distance downstream. The distance over which an arbitrary percentage (typically 80%) of this change occurs is defined as the mixing zone length, which increases with increasing average distance traveled by the displacement front. Alternatively, for continuous injection, the mixing zone size can be determined from a breakthrough curve as the time required for the effluent displacing fluid concentration to change from, say, 10% to 90%. In classical dispersion theory, the mixing zone grows in proportion to the square root of the mean distance traveled, or, equivalently, to the square root of the mean breakthrough time. In a multi-dimensional heterogeneous medium, especially at field scales, the size of the mixing zone grows almost linearly with mean distance or travel time. If an observed breakthrough curve is forced to fit the classical theory, the resulting effective dispersivity, instead of being constant, also increases almost linearly with the spatial or temporal scale of the problem. This occurs because the heterogeneity in flow properties creates a corresponding velocity distribution along the different flow pathways from the inlet to the outlet of the system. Mixing occurs mostly at the outlet, or wherever the fluid is sampled, rather than within the medium. In this paper, we consider the effects of this behavior on radionuclide or other contaminant migration

  13. A laboratory dispersant effectiveness test which reflects dispersant efficiency in the field

    International Nuclear Information System (INIS)

    Lunel, T.; Wood, P.

    1996-01-01

    Oil dispersion efficiencies of surfactants, from laboratory dispersion tests and field data were compared and calibrated. Data from an oil spill, where dispersants were used as a major part of the response, was analysed. The data was accumulated through the monitoring of the dispersant operation of the Sea Empress spill incident, in which Forties Blend oil was spilled at sea. This detailed data set was used to calibrate existing laboratory dispersant tests, and to devise a new International Dispersant Effectiveness Test. The objective was to create a comprehensive guide to decision making on whether and when to start a dispersant spraying operation. The dispersion efficiencies obtained from the laboratory dispersant tests were compared with field data. Flume tests produced the highest percentage of dispersed oil for all the dispersal tests. However, it was emphasised that the total percentage of oil dispersed should not be the only measure of dispersant effectiveness, since it does not distinguish between the contribution of natural and chemically enhanced dispersion. 9 refs., 1 tab., 9 figs

  14. Pollen Forecast and Dispersion Modelling

    Science.gov (United States)

    Costantini, Monica; Di Giuseppe, Fabio; Medaglia, Carlo Maria; Travaglini, Alessandro; Tocci, Raffaella; Brighetti, M. Antonia; Petitta, Marcello

    2014-05-01

    The aim of this study is monitoring, mapping and forecast of pollen distribution for the city of Rome using in-situ measurements of 10 species of common allergenic pollens and measurements of PM10. The production of daily concentration maps, associated to a mobile phone app, are innovative compared to existing dedicated services to people who suffer from respiratory allergies. The dispersal pollen is one of the most well-known causes of allergic disease that is manifested by disorders of the respiratory functions. Allergies are the third leading cause of chronic disease and it is estimated that tens millions of people in Italy suffer from it. Recent works reveal that during the last few years there was a progressive increase of affected subjects, especially in urban areas. This situation may depend: on the ability to transport of pollutants, on the ability to react between pollutants and pollen and from a combination of other irritants, existing in densely populated and polluted urban areas. The methodology used to produce maps is based on in-situ measurements time series relative to 2012, obtained from networks of air quality and pollen stations in the metropolitan area of Rome. The monitoring station aerobiological of University of Rome "Tor Vergata" is located at the Department of Biology. The instrument used to pollen monitoring is a volumetric sampler type Hirst (Hirst 1952), Model 2000 VPPS Lanzoni; the data acquisition is carried out as reported in Standard UNI 11008:2004 - "Qualità dell'aria - Metodo di campionamento e conteggio dei granuli pollinici e delle spore fungine aerodisperse" - the protocol that describes the procedure for measuring of the concentration of pollen grains and fungal spores dispersed into the atmosphere, and reported in the "Manuale di gestione e qualità della R.I.M.A" (Travaglini et. al. 2009). All 10 allergenic pollen are monitored since 1996. At Tor Vergata university is also operating a meteorological station (SP2000, CAE

  15. Tomography with energy dispersive diffraction

    Science.gov (United States)

    Stock, S. R.; Okasinski, J. S.; Woods, R.; Baldwin, J.; Madden, T.; Quaranta, O.; Rumaiz, A.; Kuczewski, T.; Mead, J.; Krings, T.; Siddons, P.; Miceli, A.; Almer, J. D.

    2017-09-01

    X-ray diffraction can be used as the signal for tomographic reconstruction and provides a cross-sectional map of the crystallographic phases and related quantities. Diffraction tomography has been developed over the last decade using monochromatic x-radiation and an area detector. This paper reports tomographic reconstruction with polychromatic radiation and an energy sensitive detector array. The energy dispersive diffraction (EDD) geometry, the instrumentation and the reconstruction process are described and related to the expected resolution. Results of EDD tomography are presented for two samples containing hydroxyapatite (hAp). The first is a 3D-printed sample with an elliptical crosssection and contains synthetic hAp. The second is a human second metacarpal bone from the Roman-era cemetery at Ancaster, UK and contains bio-hAp which may have been altered by diagenesis. Reconstructions with different diffraction peaks are compared. Prospects for future EDD tomography are also discussed.

  16. Determination of dispersity of crushed granite

    International Nuclear Information System (INIS)

    Liu Dejun; Fan Xianhua; Zhang Yingjie; Yao Jun; Zhou Duo; Wang Yong

    2004-01-01

    The experimental crushed granite column breakthrough curves, using 99 Tc as spike tracer and 3 H as invariant tracer, are analyzed by different linear regression techniques. Dispersity of crushed granite and retardation factor of 99 TcO 4 - on the crushed granite are determined simultaneously by one linear regression technique. Dispersity of crushed granite is also obtained with 3 H as invariant tracer by the other linear regression technique. The dispersities found by spike source and invariant source methods are compared. The experimental results show that the dispersity found by spike source method is close to that found by invariant source method. It indicates that dispersity is only the characteristic of dispersion medium

  17. Determination of dispersity of crushed granite

    International Nuclear Information System (INIS)

    Liu, D.J.; Fan, X.H.

    2005-01-01

    Experimental crushed granite column breakthrough curves, using 99 Tc as spike tracer and 3 H as invariant tracer, were analyzed by different linear regression techniques. Dispersity of crushed granite and the retardation factor of 99 TcO 4 - on the crushed granite were determined simultaneously by one linear regression. Dispersity of crushed granite was also obtained with 3 H as invariant tracer by the other linear regression. The dispersities found by spike source and invariant source methods are compared. Experimental results show that the dispersity found by the spike source method is close to that found by the invariant source method. This indicates that dispersity is only a characteristic of the dispersion medium. (author)

  18. Integrating individual movement behaviour into dispersal functions.

    Science.gov (United States)

    Heinz, Simone K; Wissel, Christian; Conradt, Larissa; Frank, Karin

    2007-04-21

    Dispersal functions are an important tool for integrating dispersal into complex models of population and metapopulation dynamics. Most approaches in the literature are very simple, with the dispersal functions containing only one or two parameters which summarise all the effects of movement behaviour as for example different movement patterns or different perceptual abilities. The summarising nature of these parameters makes assessing the effect of one particular behavioural aspect difficult. We present a way of integrating movement behavioural parameters into a particular dispersal function in a simple way. Using a spatial individual-based simulation model for simulating different movement behaviours, we derive fitting functions for the functional relationship between the parameters of the dispersal function and several details of movement behaviour. This is done for three different movement patterns (loops, Archimedean spirals, random walk). Additionally, we provide measures which characterise the shape of the dispersal function and are interpretable in terms of landscape connectivity. This allows an ecological interpretation of the relationships found.

  19. Single-particle dispersion in compressible turbulence

    Science.gov (United States)

    Zhang, Qingqing; Xiao, Zuoli

    2018-04-01

    Single-particle dispersion statistics in compressible box turbulence are studied using direct numerical simulation. Focus is placed on the detailed discussion of effects of the particle Stokes number and turbulent Mach number, as well as the forcing type. When solenoidal forcing is adopted, it is found that the single-particle dispersion undergoes a transition from the ballistic regime at short times to the diffusive regime at long times, in agreement with Taylor's particle dispersion argument. The strongest dispersion of heavy particles is announced when the Stokes number is of order 1, which is similar to the scenario in incompressible turbulence. The dispersion tends to be suppressed as the Mach number increases. When hybrid solenoidal and compressive forcing at a ratio of 1/2 is employed, the flow field shows apparent anisotropic property, characterized by the appearance of large shock wave structures. Accordingly, the single-particle dispersion shows extremely different behavior from the solenoidal forcing case.

  20. Membranes as separators of dispersed emulsion phases

    OpenAIRE

    Lefferts, A.G.

    1997-01-01

    The reuse or discharge of industrial waste waters, containing small fractions of dispersed oil, requires a purification treatment for which membranes can be used. If only little oil is present, removal of the dispersed phase might be preferable to the more commonly applied removal of the continuous phase. For this purpose dispersed phase separators can be applied, which combine the features of conventional coalescers and membrane filtration. The membrane surface promotes coalescence ...

  1. Formulation of disperse systems science and technology

    CERN Document Server

    Tadros, Tharwat F

    2014-01-01

    This book presents comprehensively the science and technology behind the formulation of disperse systems like emulsions, suspensions, foams and others. Starting with a general introduction, the book covers a broad range of topics like the role of different classes of surfactants, stability of disperse systems, formulation of different dispersions, evaluation of formulations and many more. Many examples are included, too. Written by the experienced author and editor Tharwart Tadros, this book is indispensable for every scientist working in the field.

  2. Key factors for UV curable pigment dispersions

    International Nuclear Information System (INIS)

    Magny, B.; Pezron, E.; Ciceron, P.H.; Askienazy, A.

    1999-01-01

    UV oligomers with good pigment dispersion are needed to allow good formulation flexibility and possibility to apply thinner films. Pigment dispersion mainly depends on three phenomena: the wetting of agglomerates, the breakage of agglomerates by mechanical stress and the stabilization of smaller agglomerates and primary particles against flocculation. It has been shown that oligomers with low viscosity and low surface tension induce a good pigment wetting. Examples of monomers and oligomers for good pigment dispersion are given

  3. Rethinking Creativity

    DEFF Research Database (Denmark)

    , symbolic and social world of culture. It brings together eminent social and cultural psychologists who study dynamic, transformative and emergent phenomena, and invites them to conceptualise creativity in ways that depart from mainstream definitions and theoretical models existing in past and present...... and the lives of those around them. It will be of key interest to both social and cultural psychologists, as well as to creativity researchers and those who, as part of their personal or professional life, try to understand creativity and develop creative forms of expression....

  4. Rethinking Deindustrialization

    DEFF Research Database (Denmark)

    Bernard, Andrew B.; Smeets, Valerie Anne Rolande; Warzynski, Frederic Michel Patrick

    This paper examines the decline in manufacturing in Denmark from 1994 to 2007. As in almost every other high-income country, manufacturing employment and the number of manufacturing firms in Denmark have been shrinking as a share of the total and in absolute levels. Most of the decline of manufac......This paper examines the decline in manufacturing in Denmark from 1994 to 2007. As in almost every other high-income country, manufacturing employment and the number of manufacturing firms in Denmark have been shrinking as a share of the total and in absolute levels. Most of the decline...... of manufacturing is due to firm exit and reduced employment at surviving manufacturers. However, a portion of the recorded decline is due to firms switching industries, from manufacturing to service sectors. We focus on this last group of firms, asking what they looked like before switched and how they fared after...... the switch. Overall this is a group of small high productivity firms that grow more rapidly after they switch. By 2007, employment at these former manufacturers equals 10 percent of manufacturing employment, reducing the apparent decline in manufacturing employment by about one half....

  5. Rethinking Extinction

    OpenAIRE

    Dunsmoor, Joseph E.; Niv, Yael; Daw, Nathaniel; Phelps, Elizabeth A.

    2015-01-01

    Extinction serves as the leading theoretical framework and experimental model to describe how learned behaviors diminish through absence of anticipated reinforcement. In the past decade, extinction has moved beyond the realm of associative learning theory and behavioral experimentation in animals and has become a topic of considerable interest in the neuroscience of learning, memory, and emotion. Here, we review research and theories of extinction, both as a learning process and as a behavior...

  6. Rethinking Russia

    OpenAIRE

    Paulauskas, Kęstutis

    2005-01-01

    The article argues that the period of “high” politics in the ever-problematic relations between Lithuania and Russia is over. At the same time, it is agued that tensions remain at the level of “low” politics, when the agenda of bilateral relations is dominated by the security interests related to Kaliningrad Oblast and Russia’s energy policy. The author claims that Lithuania should take a more pragmatic approach in her day-to-day relations with Russia and follow a more flexible policy towards...

  7. Rethinking Schizophrenia

    OpenAIRE

    Insel, Thomas R.

    2010-01-01

    How will we view schizophrenia in 2030? Schizophrenia today is a chronic, frequently disabling mental disorder that affects about one per cent of the world's population. After a century of studying schizophrenia, the cause of the disorder remains unknown. Treatments, especially pharmacological treatments, have been in wide use for nearly half a century, yet there is little evidence that these treatments have substantially improved outcomes for most people with schizophrenia. These current uns...

  8. Rethinking Failure

    Science.gov (United States)

    Fouché, Jaunine

    2013-01-01

    Which is better--telling high school students they are wrong, or letting them figure it out for themselves? Research supports the latter. In other words, do nit short-circuit students; struggles to achieve understanding as they grapple with their own beliefs. Removing that struggle may deny students the mechanism they need to replace their…

  9. Rethinking trust.

    Science.gov (United States)

    Kramer, Roderick M

    2009-06-01

    Will we ever learn? We'd barely recovered from Enron and WorldCom before we faced the subprime mortgage meltdown and more scandals that shook our trust in businesspeople. Which raises the question: Do we trust too much? In this article, Stanford professor and social psychologist Kramer explores the reasons we trust so easily--and, often, so unwisely. He explains that genetics and childhood learning make us predisposed to trust and that it's been a good survival mechanism. That said, our willingness to trust makes us vulnerable. Our sense of trust kicks in on remarkably simple cues, such as when people look like us or are part of our social group. We also rely on third parties to verify the character of others, sometimes to our detriment (as the victims of Bernard Madoff learned). Add in our illusions of invulnerability and our tendencies to see what we want to see and to overestimate our own judgment, and the bottom line is that we're often easily fooled. We need to develop tempered trust. For those who trust too much, that means reading cues better; for the distrustful, it means developing more receptive behaviors. Everyone should start with small acts of trust that encourage reciprocity and build up. Having a hedge against potential abuses also helps. Hollywood scriptwriters, for instance, register their treatments with the Writers Guild of America to prevent their ideas from being stolen by the executives they pitch. To attract the right relationships, people must strongly signal their own honesty, proactively allay concerns, and, if their trust is abused, retaliate. Trusting individuals in certain roles, which essentially means trusting the system that selects and trains them, also works but isn't foolproof. And don't count on due diligence alone for protection; constant vigilance is needed to make sure the landscape hasn't changed.

  10. Rethinking Gamification

    OpenAIRE

    Ruffino, Paolo

    2014-01-01

    Gamification marks a major change to everyday life. It describes the permeation of economic, political, and social contexts by game-elements such as awards, rule structures, and interfaces that are inspired by video games. Sometimes the term is reduced to the implementation of points, badges, and leaderboards as incentives and motivations to be productive. Sometimes it is envisioned as a universal remedy to deeply transform society toward more humane and playful ends. Despite its use by corpo...

  11. Rethinking Counterinsurgency

    Science.gov (United States)

    2008-01-01

    in national and local governments, in the evolution of the English language, in the arts, in the media, and even in British cuisine . However...by Russian, U.S., British, French , Portuguese, Spanish, Indian, and Israeli soldiers. For several reasons, there is a stronger sense of continuity...insurgencies encountered by the British, French , Spanish, Portuguese, Americans, and Indians, each element represented in this equation was based in and

  12. Rethinking Plagiarism

    Science.gov (United States)

    Nealy, Chynette

    2011-01-01

    Plagiarism, presenting someone's words or other creative products as one's own, is a mandatory discussion and writing assignment in many undergraduate business communication courses. Class discussions about this topic tend to be lively, ranging from questions about simply omitting identified sources to different standards of ethical behaviors…

  13. Rethinking Relativism.

    Science.gov (United States)

    Nathan, George J.

    1991-01-01

    Discusses Allan Bloom's "The Closing of the American Mind," examining his critique of relativism, particularly cultural relativism. The paper states that the existence of cultural relativism is a cause and sign of significant fragmentation and separateness in modern society and the university. (SM)

  14. Rethinking Antiquarianism

    Directory of Open Access Journals (Sweden)

    Tim Murray

    2007-11-01

    Full Text Available This paper provides the opportunity to discuss the rationale for a new collaborative research project directed at creating a global history of antiquarianism. Conventional histories of archaeology, particularly those by Daniel (e.g. 1976 and to a certain extent Trigger (1987, 2006, stress that antiquarians were in essence amateurs and dilettantes, perfect figures of their age, exemplified by the brilliantly scatty John Aubrey, or by Walter Scott’s grotesque pastiche Jonathan Oldbuck. However, following ground-breaking work by Arnoldo Momigliano (see e.g. 1966, 1990, and later by Alain Schnapp (e.g. 1996 for some time it had become clear that this was an inaccurate rendering – one designed to stress the scientific credentials of the disciplines that grew out and away from antiquarianism: the modern cultural sciences of history, sociology, anthropology, art history, archaeology, and history of religion. For Schnapp, especially in his Discovery of the Past, the division between amateur and professional (a distinction also explored with profit by Phillipa Levine (1986 was not the cause of the triumph of archaeology (or any one of the other disciplines over antiquarianism, and it is ill informed to interpret antiquarianism as a wrong-turning on the pathway to archaeological enlightenment. In this view antiquarianism was, and perhaps still is a full-fledged and (more important continuing body of thought and practice.

  15. Rethinking Strategy

    Science.gov (United States)

    1992-04-01

    Cooperation Council (GCC), a regional economic and security alliance between Saudi Arabia, Kuwait, Oman, Bahrain, Qatar , and the United Arab Emirates. (1...west bank of the Jordan River provides 25 percent of the water to the aquife ±r from which Israel draws its water. (1:-) 4. Authoritarian Nature of

  16. Rethinking Extinction

    Science.gov (United States)

    Dunsmoor, Joseph E.; Niv, Yael; Daw, Nathaniel; Phelps, Elizabeth A.

    2015-01-01

    Extinction serves as the leading theoretical framework and experimental model to describe how learned behaviors diminish through absence of anticipated reinforcement. In the past decade, extinction has moved beyond the realm of associative learning theory and behavioral experimentation in animals and has become a topic of considerable interest in the neuroscience of learning, memory, and emotion. Here, we review research and theories of extinction, both as a learning process and as a behavioral technique, and consider whether traditional understandings warrant a re-examination. We discuss the neurobiology, cognitive factors, and major computational theories, and revisit the predominant view that extinction results in new learning that interferes with expression of the original memory. Additionally, we reconsider the limitations of extinction as a technique to prevent the relapse of maladaptive behavior, and discuss novel approaches, informed by contemporary theoretical advances, that augment traditional extinction methods to target and potentially alter maladaptive memories. PMID:26447572

  17. Rethinking technologies

    National Research Council Canada - National Science Library

    Conley, Verena Andermatt

    1993-01-01

    .... Katherine Hayles 11. The Leap and the Lapse: Hacking a Private Site in Cyberspace Alberto Moreiras 12. Telefigures and Cyberspace Patrick Clancy 173 191 207 Works Cited 233 Contributors 241 Index 24...

  18. Rethinking Neoliberalism

    DEFF Research Database (Denmark)

    Dean, Mitchell

    2014-01-01

    There are many key questions concerning the current status of the notion of neoliberalism. What is it? Is it an appropriate concept to describe a political and intellectual movement or form of state? What are its prospects as a framework of public policy after the global financial crisis? The art......There are many key questions concerning the current status of the notion of neoliberalism. What is it? Is it an appropriate concept to describe a political and intellectual movement or form of state? What are its prospects as a framework of public policy after the global financial crisis......? The article proposes a way of answering these questions by regarding neoliberalism as a definite ‘thought collective’ and a regime of government of and by the state. It exemplifies these by shifts within neoliberalism regarding the question of monopoly, its relationship to classical liberalism and its...

  19. Rethinking Receivership

    OpenAIRE

    John Armour; Sandra Frisby

    2000-01-01

    A popular perception is that administrative receivers and their appointors hold 'too much' power in relation to troubled companies. Consideration of this issue is timely, because insolvency law is currently under review. We argue although the law's formal structure is imbalanced, this can nevertheless generate savings for parties by allowing a concentrated creditor who has invested in information-gathering about the debtor to conduct a private insolvency procedure. We suggest that this proced...

  20. Rethinking wedges

    Science.gov (United States)

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

    2013-03-01

    Abstract Stabilizing CO2 emissions at current levels for fifty years is not consistent with either an atmospheric CO2 concentration below 500 ppm or global temperature increases below 2 °C. Accepting these targets, solving the climate problem requires that emissions peak and decline in the next few decades, and ultimately fall to near zero. Phasing out emissions over 50 years could be achieved by deploying on the order of 19 'wedges', each of which ramps up linearly over a period of 50 years to ultimately avoid 1 GtC y-1 of CO2 emissions. But this level of mitigation will require affordable carbon-free energy systems to be deployed at the scale of tens of terawatts. Any hope for such fundamental and disruptive transformation of the global energy system depends upon coordinated efforts to innovate, plan, and deploy new transportation and energy systems that can provide affordable energy at this scale without emitting CO2 to the atmosphere. 1. Introduction In 2004, Pacala and Socolow published a study in Science arguing that '[h]umanity can solve the carbon and climate problem in the first half of this century simply by scaling up what we already know how to do' [1]. Specifically, they presented 15 options for 'stabilization wedges' that would grow linearly from zero to 1 Gt of carbon emissions avoided per year (GtC y-1 1 Gt = 1012 kg) over 50 years. The solution to the carbon and climate problem, they asserted, was 'to deploy the technologies and/or lifestyle changes necessary to fill all seven wedges of the stabilization triangle'. They claimed this would offset the growth of emissions and put us on a trajectory to stabilize atmospheric CO2 concentration at 500 ppm if emissions decreased sharply in the second half of the 21st century. The wedge concept has proven popular as an analytical tool for considering the potential of different technologies to reduce CO2 emissions. In the years since the paper was published, it has been cited more than 400 times, and stabilization wedges have become a ubiquitous unit in assessing different strategies to mitigate climate change (e.g. [2-5]). But the real and lasting potency of the wedge concept was in dividing the daunting problem of climate change into substantial but tractable portions of mitigation: Pacala and Socolow gave us a way to believe that the energy-carbon-climate problem was manageable. An unfortunate consequence of their paper, however, was to make the solution seem easy (see, e.g. [6, 7]). And in the meantime, the problem has grown. Since 2004, annual emissions have increased and their growth rate has accelerated, so that more than seven wedges would now be necessary to stabilize emissions and—more importantly—stabilizing emissions at current levels for 50 years does not appear compatible with Pacala and Socolow's target of an atmospheric CO2 concentration below 500 ppm nor the international community's goal of limiting the increase in global mean temperature to 2 °C more than the pre-industrial era. Here, we aim to revitalize the wedge concept by redefining what it means to 'solve the carbon and climate problem for the next 50 years'. This redefinition makes clear both the scale and urgency of innovating and deploying carbon-emissions-free energy technologies. 2. Solving the climate problem Stabilizing global climate requires decreasing CO2 emissions to near zero [8-11]. If emissions were to stop completely, global temperatures would quickly stabilize and decrease gradually over time [8, 12, 13]. But socioeconomic demands and dependence on fossil-fuel energy effectively commit us to many billions of tons of CO2 emissions [14], and at the timescale of centuries, each CO2 emission to the atmosphere contributes another increment to global warming: peak warming is proportional to cumulative CO2 emissions [15, 16]. Cumulative emissions, in turn, integrate all past emissions as well as those occurring during three distinct phases of mitigation: (1) slowing growth of emissions, (2) stopping growth of emissions, and (3) reducing emissions. Although they noted that stabilizing the climate would require emissions to 'eventually drop to zero', Pacala and Socolow nonetheless defined 'solv[ing] the carbon and climate problem over the next half-century' as merely stopping the growth of emissions (phases 1 and 2). Further reductions (phase 3), they said, could wait 50 years if the level of emissions were held constant in the meantime. But growth of emissions has not stopped (phase 2) or even slowed (phase 1), it has accelerated [17, 18]. In 2010, annual CO2 emissions crested 9 GtC. At this level, holding emissions constant for 50 years (phase 2) is unlikely to be sufficient to avoid the benchmark targets of 500 ppm or 2 °C. To support this assertion, we performed ensemble simulations using the UK Met Office coupled climate/carbon cycle model, HadCM3L (see supplementary material available at stacks.iop.org/ERL/8/011001/mmedia), to project changes in atmospheric CO2 and global mean temperature in response to emissions scenarios in which seven wedges (W7) and nine wedges (W9) were immediately subtracted from the A2 marker scenario of the Intergovernmental Panel on Climate Change (IPCC)'s Special Report on Emissions Scenarios (SRES) [19] beginning in 2010 (figure 1). In the first half of this century, the A2 scenario is near the center of the plume of variation of the SRES emissions scenarios [20]. Indeed, actual annual emissions have exceeded A2 projections for more than a decade [21, 22]. During this period, strong growth of global emissions has been driven by the rapid, carbon-intensive growth of emerging economies [23, 24], which has continued despite the global financial crisis of 2008-9 [18]. For these reasons we believe that, among the SRES scenarios, A2 represents a reasonable 'business-as-usual' scenario. However, if emissions were to suddenly decline and follow a lower emissions business-as-usual trajectory such as B2, fewer wedges would be necessary to stabilize emissions, and deployment of seven wedges would reduce annual emissions to 4.5 GtC in 2060. Thus, mitigation effort (wedges) required to stabilize emissions is dependent on the choice of baseline scenario, but a half-century of emissions at the current level will have the same effect on atmospheric CO2 and the climate regardless of what scenario is chosen. Figure 1 Figure 1. Modeled effects of deploying wedges. (A) Future CO2 emissions under SRES A2 marker scenario and the A2 scenario reduced by deployment of 7 wedges (W7). The response of (B) atmospheric CO2 and (C) global mean surface temperature under W7. (D) Future CO2 emissions under SRES A2 marker scenario and stabilized at 2010 levels (reduced by approximately 9 wedges relative to the A2 scenario) (W9). The response of (E) atmospheric CO2 and (F) global mean surface temperature under W9. Error bars in ((C) and (F)) are 2-sigma. Dashed lines in (A), (B), (D) and (E) show emissions and concentrations of representative concentration pathways RCP4.5, RCP6, and RCP8.5 [38]. Mean temperatures reflect warming relative to the pre-industrial era. We also note that the climate model we used, HadCM3L, has a strong positive climate/carbon cycle feedback mainly associated with the dieback of the Amazon rainforest [25]. As a result, HadCM3L projected the highest level of atmospheric CO2 concentrations among eleven Earth system models that were driven by a certain CO2 emission scenario [26]. However, this strong positive climate/carbon cycle feedback operates in simulations of both the A2 and wedge (W7 and W9) scenarios. Therefore, the relative effect of wedges, as opposed to the absolute values of projected atmospheric CO2 and temperature, is expected to be less dependent on the strength of climate/carbon cycle feedback. Atmospheric CO2 concentration and mean surface temperatures continue to rise under the modeled W7 scenario (figures 1(A)-(C)). Deploying 7 wedges does not alter projected mean surface temperatures by a statistically significant increment until 2046 (α = 0.05 level), at which time the predicted difference between mean temperatures in the A2 and W7 scenarios is 0.14 ± 0.08 °C. In 2060, the difference in projected mean temperatures under the two scenarios is 0.47 ± 0.07 °C. Further, under the W7 scenario, our results indicate atmospheric CO2 levels will exceed 500 ppm in 2042 (reaching 567 ± 1 ppm in 2060) (figure 1(B)), and 2 °C of warming in 2052 (figure 1(C)). Immediately stabilizing global emissions at 2010 levels (~10.0 GtCy-1), which would require approximately nine wedges (thus W9) under the A2 scenario, has a similarly modest effect on global mean surface temperatures and atmospheric CO2, with warming of 1.92 ± 0.4 °C in 2060 and atmospheric CO2 exceeding 500 ppm by 2049 (figures 1(D)-(F)). Our projections therefore indicate that holding emissions constant at current levels for the next half-century would cause substantial warming, approaching or surpassing current benchmarks [27-29] even before any reduction of emissions (phase 3) begins. Insofar as current climate targets accurately reflect the social acceptance of climate change impacts, then, solving the carbon and climate problem means not just stabilizing but sharply reducing CO2 emissions over the next 50 years. We are not alone in drawing this conclusion (see, e.g. [30-32]). For example, at least some integrated assessment models have now found that the emissions reductions required to prevent atmospheric CO2 concentration from exceeding 450 ppm are no longer either physically or economically feasible [11, 33, 34], and that preventing CO2 concentration from exceeding 550 ppm will also be difficult if participation of key countries such as China and Russia is delayed [11]. Most model scenarios that allow CO2 concentrations to stabilize at 450 ppm entail negative carbon emissions, for example by capturing and storing emissions from bioenergy [11]. A different body of literature has concluded that cumulative emissions of 1 trillion tons of carbon (i.e. 1000 GtC) are likely to result in warming of 2 °C [15, 35]. Whereas Pacala and Socolow's original proposal implied roughly 944 GtC of cumulative emissions (305 GtC prior to 2004, 389 GtC between 2004 and 2054, and another 250 GtC between 2054 and 2104 if emissions decrease at 2% y-1 as they suggested), stabilizing emissions at 2010 levels for 50 y and decreasing at 2% y-1 afterward increases the cumulative total to 1180 GtC of emissions (356 GtC prior to 2010, 491 GtC between 2010 and 2060, and 336 GtC between 2060 and 2110 at which time annual emissions remain at nearly 3.2 GtC y-1). Lastly, we note that even though emissions in the lowest of the new representative concentration pathways (RCP2.6) peak in 2020 at just 10.3 GtC y-1 and decline sharply to only 2.0 GtC y-1 in 2060 (figure 2), the concentration of atmospheric CO2 nonetheless reaches 443 ppm in 2050 [36-38]. In contrast, emissions of the intermediate pathway RCP4.5 rise modestly to 11.5 GtC y-1 in 2040 before declining to 9.6 GtC y-1 in 2060, which leads to atmospheric CO2 concentrations of 509 ppm in 2060 on the way to 540 ppm in 2100. These pathways, along with the integrated assessment models and cumulative emissions simulations all support our finding that 50 y of current emissions is not a solution to climate change. Figure 2 Figure 2. Idealization of future CO2 emissions under the business-as-usual SRES A2 marker scenario. Future emissions are divided into hidden (sometimes called 'virtual') wedges (brown) of emissions avoided by expected decreases in the carbon intensity of GDP by ~1% per year, stabilization wedges (green) of emissions avoided through mitigation efforts that hold emissions constant at 9.8 GtC y-1 beginning in 2010, phase-out wedges (purple) of emissions avoided through complete transition of technologies and practices that emit CO2 to the atmosphere to ones that do not, and allowed emissions (blue). 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 almost all scenarios of future emissions may underestimate the extent to which rising energy demand will be met by increased use of coal and unconventional fossil fuels [24, 41]. Moreover, there is no way to know whether a wedge created by deploying carbon-free energy technology represents additional mitigation effort (i.e. a stabilization wedge) or something that would have happened in the course of normal technological progress (i.e. a hidden wedge). Thus, in assessing the efficacy of efforts to reduce emissions, it may be more useful to tabulate wedges based only on the current carbon intensity of global energy and food production and projected demand for energy and food, without reference to any particular technology scenario. Doing so would clarify the full level of decarbonization necessary and remove the question of whether emissions reductions that do occur should count as mitigation or not. But even assuming that historical rates of decarbonization will persist and therefore that many hidden wedges will materialize, phasing-out emissions altogether will entail nearly three times the number of additional wedges that Pacala and Socolow originally proposed—a total of 19 wedges under the A2 scenario (figure 2). 4. The urgent need for innovation Confronting the need for as many as 31 wedges (12 hidden, 9 stabilization and 10 phase-out), the question is whether there are enough affordable mitigation options available, and—because the main source of CO2 emissions is the burning of fossil fuels—the answer depends upon an assessment of carbon-free energy technologies. There is a longstanding disagreement in the literature between those who argue that existing technologies, improved incrementally, are all that is needed to solve the climate problem (e.g. [1]) and others who argue that more transformational change is necessary (e.g. 42]). Although the disagreement has turned on the definitions of incremental and transformative and the trade-offs of a near-term versus a longer-term focus, the root difference lies in the perceived urgency of the climate problem [6]. The emission reductions required by current targets, let alone a complete phase-out of emissions, demand fundamental, disruptive changes in the global energy system over the next 50 years. Depending on what sort of fossil-fuel infrastructure is replaced and neglecting any emissions produced to build and maintain the new infrastructure (see, e.g. [43]), a single wedge represents 0.7-1.4 terawatts (TW) of carbon-free energy (or an equivalent decrease in demand for fossil energy). Whether the changes to the energy system are called incremental or revolutionary, few would dispute that extensive innovation of technologies will be necessary to afford many terawatts of carbon-free energy and reductions in energy demand [42, 44, 45]. Currently, only a few classes of technologies might conceivably provide carbon-free power at the scale of multiple terawatts, among them fossil fuels with carbon capture and storage (CCS), nuclear, and renewables (principally solar and wind, and perhaps biomass) [42, 46, 47]. However, CCS has not yet been commercially deployed at any centralized power plant; the existing nuclear industry, based on reactor designs more than a half-century old and facing renewed public concerns of safety, is in a period of retrenchment, not expansion; and existing solar, wind, biomass, and energy storage systems are not yet mature enough to provide affordable baseload power at terawatt scale. Each of these technologies must be further developed if they are to be deployed at scale and at costs competitive with fossil energy. Yet because investments in the energy sector tend to be capital intensive and long term, research successes are often not fully appropriable [48], and technologies compete almost entirely on the price of delivered electricity, private firms tend to underinvest in R&D, which has made energy one of the least innovative industry sectors in modern economies [44]. Supporting deployment of newer energy technologies at large scales will undoubtedly lead to further development and reduced costs [49, 50], but additional public support for early stage R&D will also be necessary to induce needed innovation [6, 44, 45, 51-53]. Moreover, it is imperative that policies and programs also address the intermediate stages of development, demonstration, and commercialization, when ideas born of public-funded research must be transferred to and diffused among private industries [44, 54, 55]. 5. Conclusions In 2004, Pacala and Socolow concluded that 'the choice today is between action and delay'. After eight years of mostly delay, the action now required is significantly greater. Current climate targets of 500 ppm and 2 °C of warming will require emissions to peak and decline in the next few decades. Solving the climate problem ultimately requires near-zero emissions. Given the current emissions trajectory, eliminating emissions over 50 years would require 19 wedges: 9 to stabilize emissions and an additional 10 to completely phase-out emissions. And if historical, background rates of decarbonization falter, 12 'hidden' wedges will also be necessary, bringing the total to a staggering 31 wedges. Filling this many wedges while sustaining global economic growth would mean deploying tens of terawatts of carbon-free energy in the next few decades. Doing so would entail a fundamental and disruptive overhaul of the global energy system, as the global energy infrastructure is replaced with new infrastructure that provides equivalent amounts of energy but does not emit CO2. Current technologies and systems cannot provide the amounts of carbon-free energy needed soon enough or affordably enough to achieve this transformation. An integrated and aggressive set of policies and programs is urgently needed to support energy technology innovation across all stages of research, development, demonstration, and commercialization. No matter the number required, wedges can still simplify and quantify the challenge. But the problem was never easy. Acknowledgments We thank six anonymous reviewers for their comments on various versions of the manuscript. We also especially thank R Socolow for several thoughtful and stimulating discussions of this work.

  1. Liquid agents for dispersion of hard alloys

    International Nuclear Information System (INIS)

    Putintseva, M.N.

    2006-01-01

    Effects of dispersant properties on granulometric, chemical, and phase composition of the products of WC hard alloy electroerosion are considered. It is established that an increase of liquid dispersant permittivity results in enhanced powder dispersity, and an increase of boiling temperature and kinematic viscosity of a hydrocarbon liquid promotes a carbon loss from WC and intensifies pyrolysis of the liquid.On electroerosion of WC base hard alloy in oil a powder particle consists of b-WC+W 2 C phases, in kerosine - of a-WC+b-WC, in distilled water - of W+W 2 C. The viscosity of liquid dispersants practically has no effect on powder particle size [ru

  2. Dispersal of Engineered Male Aedes aegypti Mosquitoes.

    Science.gov (United States)

    Winskill, Peter; Carvalho, Danilo O; Capurro, Margareth L; Alphey, Luke; Donnelly, Christl A; McKemey, Andrew R

    2015-11-01

    Aedes aegypti, the principal vector of dengue fever, have been genetically engineered for use in a sterile insect control programme. To improve our understanding of the dispersal ecology of mosquitoes and to inform appropriate release strategies of 'genetically sterile' male Aedes aegypti detailed knowledge of the dispersal ability of the released insects is needed. The dispersal ability of released 'genetically sterile' male Aedes aegypti at a field site in Brazil has been estimated. Dispersal kernels embedded within a generalized linear model framework were used to analyse data collected from three large scale mark release recapture studies. The methodology has been applied to previously published dispersal data to compare the dispersal ability of 'genetically sterile' male Aedes aegypti in contrasting environments. We parameterised dispersal kernels and estimated the mean distance travelled for insects in Brazil: 52.8 m (95% CI: 49.9 m, 56.8 m) and Malaysia: 58.0 m (95% CI: 51.1 m, 71.0 m). Our results provide specific, detailed estimates of the dispersal characteristics of released 'genetically sterile' male Aedes aegypti in the field. The comparative analysis indicates that despite differing environments and recapture rates, key features of the insects' dispersal kernels are conserved across the two studies. The results can be used to inform both risk assessments and release programmes using 'genetically sterile' male Aedes aegypti.

  3. Effectiveness of dispersants on thick oil slicks

    International Nuclear Information System (INIS)

    Ross, S.; Belore, R.

    1993-01-01

    Experiments were conducted to determine the relationship between dispersant effectiveness and oil slick thickness, and thereby determine the optimum time for applying dispersant onto spilled oil at sea. Tests were completed at a lab-scale level by varying the three parameters of oil type, dispersant application, and oil thickness. The tests were intended to be comparative only. The primary oils used were Alberta sweet mix blend and Hibernia B-27 crude. The dispersant, Corexit 9527, was applied either premixed with the oil, dropwise in one application, or dropwise in multiple applications to simulate a multi-hit aircraft operation. The apparatus used in the experiment was an oscillating hoop tank, with oil-containing rings used to obtain and maintain uniform slick thickness. The results indicate that the effectiveness potential of a chemical dispersant does not decrease as slick thickness increases. In fact, results of the tests involving Hibernia oil suggest that oils that tend to herd easily would be treated more effectively if dispersant were applied when the oil was relatively thick (1 mm or greater) to avoid herding problems. The oil slicks premixed with dispersant did not disperse well in the thick oil tests, not because of dispersant-oil interaction problems but because of reduced mixing energy. 6 refs., 4 figs., 1 tab

  4. Modelling airborne dispersion of coarse particulate material

    International Nuclear Information System (INIS)

    Apsley, D.D.

    1989-03-01

    Methods of modelling the airborne dispersion and deposition of coarse particulates are presented, with the emphasis on the heavy particles identified as possible constituents of releases from damaged AGR fuel. The first part of this report establishes the physical characteristics of the irradiated particulate in airborne emissions from AGR stations. The second part is less specific and describes procedures for extending current dispersion/deposition models to incorporate a coarse particulate component: the adjustment to plume spread parameters, dispersion from elevated sources and dispersion in conjunction with building effects and plume rise. (author)

  5. By a communicative action/supervison: Haberma's strategy to rethink the educational practices in the Project of Professiobalization of Workers in the Field Nursing.

    Directory of Open Access Journals (Sweden)

    Elioenai Dornelles Alves

    2012-01-01

    Full Text Available This philosophical reflection search to build some guide elements that can subsidize the discussions on the teaching methodologies in health and nursing, while philosophical referencial to rethink the pedagogic political projects used in the qualification of human resources in health and of the implications with the offers of courses, projects, researches and activities related to extension action the permanent education in health. This study search to rescue a critical and creative approach of the educators in health, contributing to a new look interdisciplinar focused philosophically of way multiprofissional, to rethink our praxis in the different acting forms.

  6. Does an ant-dispersed plant, Viola reichenbachiana, suffer from reduced seed dispersal under inundation disturbances?

    NARCIS (Netherlands)

    Prinzing, A.; Dauber, J.; Hammer, E.; Hammouti, N.; Bohning-Gaese, K.

    2008-01-01

    Many plant species use ants as seed dispersers. This dispersal mode is considered to be susceptible to disturbances, but the effect of natural, small-scale disturbances is still unknown. We investigated how small-scale disturbances due to inundation affect seed dispersal in Viola reichenbachiana, a

  7. Dispersed and decentralised settlement system

    Directory of Open Access Journals (Sweden)

    Andrej Černe

    2004-01-01

    Full Text Available In the process of reintegration of the urban system new settlements are emerging on theurban rim, transitional zones are reurbanised, derelict areas within the cities are being developedand degraded urban areas of derelict industrial complexes are being renaturalised. Inthe periphery combined research and production parks are being set up, in the open landscapeintegrated business, trade and recreational centres are springing up. Decentralisationand recentralisation of focal points of development accompany the contemporary processesof reurbanisation and suburbanisation – they are simultaneous and move in two-direction i.e. to and from the city. We understand them as manifestation of a dynamic balance amongcontradiction existing between the centre and the rim. Deindustrialisation and relocation ofproduction and distribution from the centres of gravity to the periphery generate extensivedegraded urban areas within cities and between the city and suburbs. The periphery is beingurbanised with the creation of new, dispersed and nonhierachical poles of development, andthe city and inner city is undergoing reurbanization. The general environmental conditionsin the city and in the countryside are being equalised, the potentials of development arebeing sought in the comparative advantages of local conditions: be it attractive urban districts,be it suburban entities or countryside areas.

  8. Databases of surface wave dispersion

    Directory of Open Access Journals (Sweden)

    L. Boschi

    2005-06-01

    Full Text Available Observations of seismic surface waves provide the most important constraint on the elastic properties of the Earth’s lithosphere and upper mantle. Two databases of fundamental mode surface wave dispersion were recently compiled and published by groups at Harvard (Ekström et al., 1997 and Utrecht/Oxford (Trampert and Woodhouse, 1995, 2001, and later employed in 3-d global tomographic studies. Although based on similar sets of seismic records, the two databases show some significant discrepancies. We derive phase velocity maps from both, and compare them to quantify the discrepancies and assess the relative quality of the data; in this endeavour, we take careful account of the effects of regularization and parametrization. At short periods, where Love waves are mostly sensitive to crustal structure and thickness, we refer our comparison to a map of the Earth’s crust derived from independent data. On the assumption that second-order effects like seismic anisotropy and scattering can be neglected, we find the measurements of Ekström et al. (1997 of better quality; those of Trampert and Woodhouse (2001 result in phase velocity maps of much higher spatial frequency and, accordingly, more difficult to explain and justify geophysically. The discrepancy is partly explained by the more conservative a priori selection of data implemented by Ekström et al. (1997. Nevertheless, it becomes more significant with decreasing period, which indicates that it could also be traced to the different measurement techniques employed by the authors.

  9. Pay Dispersion and Performance in Teams

    DEFF Research Database (Denmark)

    Bucciol, Alessandro; Foss, Nicolai J; Piovesan, Marco

    2014-01-01

    Extant research offers conflicting predictions about the effect of pay dispersion on team performance. We collected a unique dataset from the Italian soccer league to study the effect of intra-firm pay dispersion on team performance, under different definitions of what constitutes a "team". This ...

  10. A new optical rotation dispersion formula

    International Nuclear Information System (INIS)

    Kimel, I.

    1981-12-01

    A new dispersion formula for the rotatory power is obtained in the framework of Kubo forlalism for transport coefficients. Unlike the well known Rosenfeld-Condon dispersion law, this formula is consistent with the free electron gas asymptotic behavior. (Author) [pt

  11. Discrete dispersion models and their Tweedie asymptotics

    DEFF Research Database (Denmark)

    Jørgensen, Bent; Kokonendji, Célestin C.

    2016-01-01

    The paper introduce a class of two-parameter discrete dispersion models, obtained by combining convolution with a factorial tilting operation, similar to exponential dispersion models which combine convolution and exponential tilting. The equidispersed Poisson model has a special place in this ap......The paper introduce a class of two-parameter discrete dispersion models, obtained by combining convolution with a factorial tilting operation, similar to exponential dispersion models which combine convolution and exponential tilting. The equidispersed Poisson model has a special place...... in this approach, whereas several overdispersed discrete distributions, such as the Neyman Type A, Pólya-Aeppli, negative binomial and Poisson-inverse Gaussian, turn out to be Poisson-Tweedie factorial dispersion models with power dispersion functions, analogous to ordinary Tweedie exponential dispersion models...... with power variance functions. Using the factorial cumulant generating function as tool, we introduce a dilation operation as a discrete analogue of scaling, generalizing binomial thinning. The Poisson-Tweedie factorial dispersion models are closed under dilation, which in turn leads to a Poisson...

  12. Seed Dispersal Potential of Asian Elephants

    DEFF Research Database (Denmark)

    Harich, Franziska K.; Treydte, Anna Christina; Ogutu, Joseph Ochieng

    2016-01-01

    Elephants, the largest terrestrial mega-herbivores, play an important ecological role in maintaining forest ecosystem diversity. While several plant species strongly rely on African elephants (Loxodonta africana; L. cyclotis) as seed dispersers, little is known about the dispersal potential of As...

  13. Interspecific nematode signals regulate dispersal behavior.

    Directory of Open Access Journals (Sweden)

    Fatma Kaplan

    Full Text Available Dispersal is an important nematode behavior. Upon crowding or food depletion, the free living bacteriovorus nematode Caenorhabditis elegans produces stress resistant dispersal larvae, called dauer, which are analogous to second stage juveniles (J2 of plant parasitic Meloidogyne spp. and infective juveniles (IJs of entomopathogenic nematodes (EPN, e.g., Steinernema feltiae. Regulation of dispersal behavior has not been thoroughly investigated for C. elegans or any other nematode species. Based on the fact that ascarosides regulate entry in dauer stage as well as multiple behaviors in C. elegans adults including mating, avoidance and aggregation, we hypothesized that ascarosides might also be involved in regulation of dispersal behavior in C. elegans and for other nematodes such as IJ of phylogenetically related EPNs.Liquid chromatography-mass spectrometry analysis of C. elegans dauer conditioned media, which shows strong dispersing activity, revealed four known ascarosides (ascr#2, ascr#3, ascr#8, icas#9. A synthetic blend of these ascarosides at physiologically relevant concentrations dispersed C. elegans dauer in the presence of food and also caused dispersion of IJs of S. feltiae and J2s of plant parasitic Meloidogyne spp. Assay guided fractionation revealed structural analogs as major active components of the S. feltiae (ascr#9 and C. elegans (ascr#2 dispersal blends. Further analysis revealed ascr#9 in all Steinernema spp. and Heterorhabditis spp. infected insect host cadavers.Ascaroside blends represent evolutionarily conserved, fundamentally important communication systems for nematodes from diverse habitats, and thus may provide sustainable means for control of parasitic nematodes.

  14. 21 CFR 178.3725 - Pigment dispersants.

    Science.gov (United States)

    2010-04-01

    ... HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: ADJUVANTS, PRODUCTION AIDS, AND SANITIZERS Certain Adjuvants and Production Aids § 178.3725 Pigment dispersants. Subject to the provisions of this... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Pigment dispersants. 178.3725 Section 178.3725 Food...

  15. Dispersions of Carbon nanotubes in Polymer Matrices

    Science.gov (United States)

    Wise, Kristopher Eric (Inventor); Park, Cheol (Inventor); Siochi, Emilie J. (Inventor); Harrison, Joycelyn S. (Inventor); Lillehei, Peter T. (Inventor); Lowther, Sharon E. (Inventor)

    2010-01-01

    Dispersions of carbon nanotubes exhibiting long term stability are based on a polymer matrix having moieties therein which are capable of a donor-acceptor complexation with carbon nanotubes. The carbon nanotubes are introduced into the polymer matrix and separated therein by standard means. Nanocomposites produced from these dispersions are useful in the fabrication of structures, e.g., lightweight aerospace structures.

  16. Membranes as separators of dispersed emulsion phases

    NARCIS (Netherlands)

    Lefferts, A.G.

    1997-01-01

    The reuse or discharge of industrial waste waters, containing small fractions of dispersed oil, requires a purification treatment for which membranes can be used. If only little oil is present, removal of the dispersed phase might be preferable to the more commonly applied removal of the

  17. A synthesis of empirical plant dispersal kernels

    Czech Academy of Sciences Publication Activity Database

    Bullock, J. M.; González, L. M.; Tamme, R.; Götzenberger, Lars; White, S. M.; Pärtel, M.; Hooftman, D. A. P.

    2017-01-01

    Roč. 105, č. 1 (2017), s. 6-19 ISSN 0022-0477 Institutional support: RVO:67985939 Keywords : dispersal kernel * dispersal mode * probability density function Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 5.813, year: 2016

  18. Interaction between molecular complexes in dispersive media

    International Nuclear Information System (INIS)

    Banagas, E.A.; Manykin, E.A.

    1987-01-01

    The interaction between molecular complexes in different dispersive media with local and nonlocal screening is investigated theoretically. On the basis of results of numerical analysis on a computer, the dependence of the coupled-system spectrum and the interaction energy of the polarized modes on the characteristic parameters of the dispersive media is considered

  19. Modeling of atmospheric dispersion of radionuclides

    International Nuclear Information System (INIS)

    Baklouti, Nada

    2010-01-01

    This work is a prediction of atmospheric dispersion of radionuclide from a chronic rejection of the nuclear power generating plant that can be located in one of the Tunisian sites: Skhira or Bizerte. Also it contains a study of acute rejection 'Chernobyl accident' which was the reference for the validation of GENII the code of modeling of atmospheric dispersion.

  20. Dispersion-induced nonlinearities in semiconductors

    DEFF Research Database (Denmark)

    Mørk, Jesper; Mecozzi, A.

    2002-01-01

    A dispersive and saturable medium is shown, under very general conditions, to possess ultrafast dynamic behaviour due to non-adiabatic polarisation dynamics. Simple analytical expressions relating the effect to the refractive index dispersion of a semiconductor ire derived and the magnitude...... of the equivalent Kerr coefficient is shown to be in qualitative agreement with measurements on active semiconductor waveguides....

  1. Modeling the dispersal of spiny lobster (

    NARCIS (Netherlands)

    Whomersley, P.; van der Molen, J.; Holt, D.; Trundle, C.; Clark, S.; Fletcher, D.

    2018-01-01

    Knowledge of larval dispersal, population dynamics and connectivity in relation to the management and conservation of commercially important species is vital if existing fisheries are to remain sustainable into the future. Larval dispersal of the commercially exploited spiny lobster, Palinurus

  2. Employment Effects of Spatial Dispersal of Refugees

    DEFF Research Database (Denmark)

    Damm, Anna Piil; Rosholm, Michael

    We argue that spatial dispersal influences labour market assimilation of refugees through two mechanisms: first, the local job offer arrival rate and, second, place utility. Our partial search model with simultaneous job and residential location search predicts that the reservation wage for local...... by evaluating the employment effects of the Danish spatial dispersal policy carried out 1986-1998....

  3. An atmospheric dispersion index for prescribed burning

    Science.gov (United States)

    Leonidas G. Lavdas

    1986-01-01

    A numerical index that estimates the atmosphere's capacity to disperse smoke from prescribed burning is described. The physical assumptions and mathematical development of the index are given in detail. A preliminary interpretation of dispersion index values is offered. A FORTRAN subroutine package for computing the index is included.

  4. Dispersive and erodible soils - fundamental differences

    CSIR Research Space (South Africa)

    Paige-Green, P

    2008-11-01

    Full Text Available Dispersive, erodible and slaking soils are prevalent over wide areas of South Africa. Each of these materials increases the cost of construction, but dispersive soils are likely to lead to far more serious problems, particularly in dam construction...

  5. Re-thinking representations, re-writing nursing texts: possibilities through feminist and Foucauldian thought.

    Science.gov (United States)

    Huntington, A D; Gilmour, J A

    2001-09-01

    Critical approaches are increasingly being used to inform theory and research within the discipline of nursing. In this paper we discuss the work of feminist writers, particularly those located within the postmodern, and Michel Foucault. Their work, although having significant points of difference, can be viewed as complementary and our engagement with these ideas has led us to re-think nursing knowledge. Using ideas from Foucault and postmodern feminism foregrounds critical questions such as whose knowledge is visible in nursing literature, whose is suppressed, and the power relationships reflected in representations of knowledge. Our exploration of representations of knowledge has led us to review fundamental nursing texts that we consider to be important political and ideological artefacts in the enculturation of student nurses. The dominant position of medical knowledge in the texts reviewed continues to position this 'voice' as primary in nursing literature. Drawing on our current research on endometriosis to illustrate the potential inherent in rewriting such texts, we argue for a repositioning of knowledge related to the illness experience. Privileging the voices of people who are the focus of our clinical care reflects the reality of nurses' work; the embodied experience of the person is made visible rather than marginalized in the illness discourse.

  6. Rethinking clinical language mapping approaches: discordant receptive and expressive hemispheric language dominance in epilepsy surgery candidates.

    Science.gov (United States)

    Gage, Nicole M; Eliashiv, Dawn S; Isenberg, Anna L; Fillmore, Paul T; Kurelowech, Lacey; Quint, Patti J; Chung, Jeffrey M; Otis, Shirley M

    2011-06-01

    Neuroimaging studies have shed light on cortical language organization, with findings implicating the left and right temporal lobes in speech processing converging to a left-dominant pattern. Findings highlight the fact that the state of theoretical language knowledge is ahead of current clinical language mapping methods, motivating a rethinking of these approaches. The authors used magnetoencephalography and multiple tasks in seven candidates for resective epilepsy surgery to investigate language organization. The authors scanned 12 control subjects to investigate the time course of bilateral receptive speech processes. Laterality indices were calculated for left and right hemisphere late fields ∼150 to 400 milliseconds. The authors report that (1) in healthy adults, speech processes activated superior temporal regions bilaterally converging to a left-dominant pattern, (2) in four of six patients, this was reversed, with bilateral processing converging to a right-dominant pattern, and (3) in three of four of these patients, receptive and expressive language processes were laterally discordant. Results provide evidence that receptive and expressive language may have divergent hemispheric dominance. Right-sided receptive language dominance in epilepsy patients emphasizes the need to assess both receptive and expressive language. Findings indicate that it is critical to use multiple tasks tapping separable aspects of language function to provide sensitive and specific estimates of language localization in surgical patients.

  7. Rethinking work and family policy: the making and taking of parental leave in Australia.

    Science.gov (United States)

    Baird, M; Litwin, A S

    2005-10-01

    Despite the continued increase in female participation rates, Australia remains one of only two developed nations in the world without a paid maternity leave scheme. While research interest and public policy debate about paid maternity leave entitlements continues, little is known about the actual utilization of the 52 weeks unpaid parental leave that is currently available to all employees. Moreover, research and policy debate on the availability and provision of paid paternity leave has only just begun. This paper argues that, given the gendered nature of employee entitlements, it is time to re-evaluate all aspects of parental leave policy in Australia. Using unique data from a national survey of Australian employees, the paper provides a statistical analysis of the use of unpaid parental leave and the availability of paid maternity leave. The paper models the availability of paid maternity leave to Australian employees as a function of demographic and organizational characteristics, including annual income, union status, and establishment size. A parallel analysis of the likelihood that an individual has used the unpaid parental leave provision is also provided. The results show that the existing unpaid parental leave provision is rarely used and that the current availability of paid maternity leave is inequitable. The paper discusses the conceptual and policy implications of these results and concludes that a re-thinking of parental leave policy in Australia is essential if gender inequities at work and in society are to be addressed.

  8. Rethinking cities in a post-carbon society. Perspectives from a prospective programme

    International Nuclear Information System (INIS)

    Vidalenc, Eric; Riviere, Antoine; Delduc, Paul; Cecutti-Etahiri, Nathalie; Theys, Jacques

    2015-03-01

    This article is inspired by an interdisciplinary research programme (Rethinking towns in the post-carbon society) and addresses two critical issues, the role of cities in this energy transition, and how cities could lead to a post-carbon society. While discussing the first issue, the authors show that cities are both victims and executioners of climate changes, but also that they possess unique levers to drive a territory towards post-carbon transition. To study the second issue, the authors relied on a scenario-based approach. Six different and contrasted trajectories have been defined to express the complexity of the urban metabolism, but also to understand, through qualitative and quantitative analysis, the potential forces in action between now and 2050. Three main stakes are then identified: the sustainability of our societies will only be reached with a combination of technical and social innovations; the modification of behaviours and lifestyles is an important component to ensure the resilience of our societies on medium and long terms; and the global coherence of transition processes must be looked for, in terms of temporalities (short, medium and long terms) as well as space scales (from the individual to the global level)

  9. RETHINKING ‘RADICALISATION’: MICRORADICALISATIONS AND RECIPROCAL RADICALISATION AS AN INTERTWINED PROCESS

    Directory of Open Access Journals (Sweden)

    Gavin Bailey

    2017-03-01

    Full Text Available This paper proposes a rethinking of ‘radicalisation’ as a process with no definite beginning or inevitable end-point. Reflecting on empirical research which engaged with radical Islamist and far-right activists and supporters, it argues that we should not focus the concept of radicalisation on the moment in which an individual or group moves from legal to illegal activity, or from non-violent to violent, as this is only one part of a longer journey. Thus, the term radicalisation should encompass any movements towards greater conflict, both commonplace and rare, small and large, driven by a potentially infinite range of motives, encompassing all political outlooks, and made by individuals, groups, societies and states. Using this conceptualisation instead allows us to examine how small conflicts escalate through ‘reciprocal radicalisation’, and how big radicalisations arise from microradicalisations. This, we argue, provides a more equitable basis for policy and practice that aims to avoid, prevent or combat the most problematic radicalisations, or otherwise resolve political conflict. To achieve this, however, also means not hyping everyday radicalisations into a threat to the existence of the nation state.

  10. Beyond the East-West Dilemma: Rethinking Greekness Through Diffracted Gazes in Contemporary Greek Travelogues

    Directory of Open Access Journals (Sweden)

    Peggy Karpouzou

    2017-06-01

    Full Text Available Travel writing has been viewed as one of the main sources of national typologies and is often held responsible for the consolidation of stereotypes about otherness and for the promotion of an imperialist agenda. This paper aims to investigate conceptions of Greekness in contemporary Greek travelogues which involve a rethinking of stereotypical national representations. The analysis proceeds by proposing the method of “questioning home” in travelogues through diffracted gazes towards the traveller’s homeland as a result of his encounter with otherness. In the second part, Greekness is explored beyond the nation-state approach and the long-held national stereotype of the “Greek particularism”, Greece’s isolation because of the country’s unresolved tension between East and West. A. Vistonitis’ and M. Kassolas’s travelogues reporting their travels to the East (China and to the West (USA respectively at the end of the 20th century are examined as case-studies. Through narrators’ dialogues with their hosts and the raising of relevant political and geopolitical issues, “transnational” conceptions of Greek identity are explored: the notions of “diaspora”, “cosmopolitan citizenship”, “openness” and “connectivity” challenge the national narration based on “purity” and “exclusion”, and facilitate the investigation of potential roles for Greece in the globalized world of the early 21st century.

  11. Human rights for more than one voice: rethinking political space beyond the global/local divide

    Directory of Open Access Journals (Sweden)

    Rebecca Adami

    2014-12-01

    Full Text Available This paper considers political agency and space as found in Cavarero's For More Than One Voice: Toward a Philosophy of Vocal Expression in order to take a critical philosophical approach to human rights education (HRE and the political implications of its increasingly legal discourse. Like Arendt, Cavarero is concerned with a radical rethinking of political space, as not limited to place or legal borders, but bound by our human condition of plurality and relationality. Both Arendt and Cavarero want politics to be coupled with justice, nevertheless, Cavarero provides a notion of politics that lets us think beyond territorial terms of a polis, which opens for exploring an expanded conceptualization of human rights politics, as not bound by national legislative measures, but as concerning political action in-between human beings. In contrast to the dominant discourse on ‘human rights experts’ who frame the content for HRE, the notion of ‘absolute local space’ questions the dichotomy of universal/particular in raising the importance of a plurality of unique voices who create a spectrum for the universality of rights.

  12. A Rethinking of the Production Approach in IPCC: Its Objectiveness in China

    Directory of Open Access Journals (Sweden)

    Hongqiang Yang

    2016-02-01

    Full Text Available The trade of harvested wood products (HWPs and their feedstock increasingly affects the dynamics of the complete national HWP carbon pool ignored by the Production Approach (PA, the current universal method, proposed by the Intergovernmental Panel on Climate Change. Existing research also overlooks the inherent factors that lead to the non-objectiveness of PA that affects the potential carbon trade and the sustainable use of forestry resources. This study aimed to investigate such inherent factors through a deductive derivation of PA and the Stock-Change Approach (SCA, based on which an empirical study on China was conducted to rethink the objectiveness of PA in the complete national HWP carbon pool. The deductive derivation indicated that the inherent factors rely on the balance between coefficients that describe the relationship between HWP trade and production and the relationship between the corresponding feedstock trade and production. The empirical study further illustrated that the dynamics of balance between coefficients negatively influence the objectiveness of PA. The absolute objectiveness of this approach was constantly weakened in the past 55 years and may potentially occur yet again in the future despite an improvement in its annual relative objectiveness.

  13. Rethinking vulnerability analysis and governance with emphasis on a participatory approach.

    Science.gov (United States)

    Rossignol, Nicolas; Delvenne, Pierre; Turcanu, Catrinel

    2015-01-01

    This article draws on vulnerability analysis as it emerged as a complement to classical risk analysis, and it aims at exploring its ability for nurturing risk and vulnerability governance actions. An analysis of the literature on vulnerability analysis allows us to formulate a three-fold critique: first, vulnerability analysis has been treated separately in the natural and the technological hazards fields. This separation prevents vulnerability from unleashing the full range of its potential, as it constrains appraisals into artificial categories and thus already closes down the outcomes of the analysis. Second, vulnerability analysis focused on assessment tools that are mainly quantitative, whereas qualitative appraisal is a key to assessing vulnerability in a comprehensive way and to informing policy making. Third, a systematic literature review of case studies reporting on participatory approaches to vulnerability analysis allows us to argue that participation has been important to address the above, but it remains too closed down in its approach and would benefit from embracing a more open, encompassing perspective. Therefore, we suggest rethinking vulnerability analysis as one part of a dynamic process between opening-up and closing-down strategies, in order to support a vulnerability governance framework. © 2014 Society for Risk Analysis.

  14. Rethinking poverty, power and privilege: A feminist post-structuralist research exploration

    Directory of Open Access Journals (Sweden)

    Thérèse Hulme

    2012-11-01

    Full Text Available In this article, I described how the use of feminist methodology and post-structuralist analyses of the experiences of women in a poor ‘Coloured’ community in my research led to new understandings of the experiences of poverty and privilege. I discovered the relevance of Foucault’s historical analysis of the operation of ‘pastoral power’ through the narratives of women from the Scottsville community. Historical and current accounts of so-called ‘Coloured’ women’s subjugation and categorisation are reminders of how it came about that ‘being Coloured’ became associated in South Africa with shame and with ‘knowing one’s place’. Feminist post-structuralist analyses made visible the conditions that created practices of injustice in poor women’s lives whilst, at the same time, creating conditions of privilege for me. Justice-making in Scottsville therefore started with a radical rethinking of the terms by which people’s marginalisation took place and, consequently also of the terms of ‘just’ cross-cultural engagements.

  15. Individual differences in the effects of mobile phone exposure on human sleep: rethinking the problem.

    Science.gov (United States)

    Loughran, Sarah P; McKenzie, Raymond J; Jackson, Melinda L; Howard, Mark E; Croft, Rodney J

    2012-01-01

    Mobile phone exposure-related effects on the human electroencephalogram (EEG) have been shown during both waking and sleep states, albeit with slight differences in the frequency affected. This discrepancy, combined with studies that failed to find effects, has led many to conclude that no consistent effects exist. We hypothesised that these differences might partly be due to individual variability in response, and that mobile phone emissions may in fact have large but differential effects on human brain activity. Twenty volunteers from our previous study underwent an adaptation night followed by two experimental nights in which they were randomly exposed to two conditions (Active and Sham), followed by a full-night sleep episode. The EEG spectral power was increased in the sleep spindle frequency range in the first 30 min of non-rapid eye movement (non-REM) sleep following Active exposure. This increase was more prominent in the participants that showed an increase in the original study. These results confirm previous findings of mobile phone-like emissions affecting the EEG during non-REM sleep. Importantly, this low-level effect was also shown to be sensitive to individual variability. Furthermore, this indicates that previous negative results are not strong evidence for a lack of an effect and, given the far-reaching implications of mobile phone research, we may need to rethink the interpretation of results and the manner in which research is conducted in this field. Copyright © 2011 Wiley Periodicals, Inc.

  16. Rethinking the concept of intercultural conflict: Italian returnees’ attitudes towards others during a cultural conflict

    Directory of Open Access Journals (Sweden)

    Mattia Baiutti

    2016-04-01

    Full Text Available The article aims to rethink the concept of intercultural conflict. Specifically, I argue that the use of the adjective “intercultural” within ‘intercultural conflict’ is usually an expression of rhetorical discourse or is not appropriate. Following a semantic analysis I show that a cultural conflict, here conceptualized as incompatibility of cultural values between a minimum of two people belonging to different cultural backgrounds, might be described as an intercultural conflict. This is possible if the interactants, rather than focussing on solutions, adopt an ‘intercultural attitude’ (comity, ethical relativism, critical self-reflection, openness toward a potential change, suspending judgment, reframing meanings, curiosity, respect, and self-decentralization between them. Existing theoretical concepts are explored through qualitative research examining supposedly interculturally competent high school students’ (after one scholastic year abroad attitudes towards others during a cultural conflict. The study shows that curiosity and respect towards others might be considered as preconditions for a true dialogue. Two main attitudes emerge from the analysis: the multicultural one and the intercultural one. The former corresponds to respect for the different ideas of others. The second is exemplified by true interaction between interactants who seek a deep understanding of what is behind the point of view held by themselves and others. Adopting an intercultural attitude, they make all possible efforts to truly encounter each other’s otherness. 

  17. Spectral dispersion and fringe detection in IOTA

    Science.gov (United States)

    Traub, W. A.; Lacasse, M. G.; Carleton, N. P.

    1990-01-01

    Pupil plane beam combination, spectral dispersion, detection, and fringe tracking are discussed for the IOTA interferometer. A new spectrometer design is presented in which the angular dispersion with respect to wavenumber is nearly constant. The dispersing element is a type of grism, a series combination of grating and prism, in which the constant parts of the dispersion add, but the slopes cancel. This grism is optimized for the display of channelled spectra. The dispersed fringes can be tracked by a matched-filter photon-counting correlator algorithm. This algorithm requires very few arithmetic operations per detected photon, making it well-suited for real-time fringe tracking. The algorithm is able to adapt to different stellar spectral types, intensity levels, and atmospheric time constants. The results of numerical experiments are reported.

  18. Pay Dispersion and Performance in Teams

    Science.gov (United States)

    Bucciol, Alessandro; Foss, Nicolai J.; Piovesan, Marco

    2014-01-01

    Extant research offers conflicting predictions about the effect of pay dispersion on team performance. We collected a unique dataset from the Italian soccer league to study the effect of intra-firm pay dispersion on team performance, under different definitions of what constitutes a “team”. This peculiarity of our dataset can explain the conflicting evidence. Indeed, we also find positive, null, and negative effects of pay dispersion on team performance, using the same data but different definitions of team. Our results show that when the team is considered to consist of only the members who directly contribute to the outcome, high pay dispersion has a detrimental impact on team performance. Enlarging the definition of the team causes this effect to disappear or even change direction. Finally, we find that the detrimental effect of pay dispersion is due to worse individual performance, rather than a reduction of team cooperation. PMID:25397615

  19. Analysis of site-specific dispersion conditions

    International Nuclear Information System (INIS)

    Paesler-Sauer, J.

    1989-03-01

    This report presents an analysis of atmospheric dispersion conditions in the environs of nuclear power stations in the Federal Republic of Germany. The analysis is based on meteorological data measured on the power station sites (KFUe = nuclear reactor remote control records) and by neighbouring stations operated by the German Weather Service. The data are series of hourly mean values of wind and temperature gradient or stability class over the period of one or more years. The aim of the data analysis is to find types of dispersion conditions characterized by the flow field and stratification, and to assess the feasibility of calculating these quantities in the case of an emergency. Influences of terrain structures in the environs of the site are considered. The annual frequencies of types of dispersion situations are assessed, the capability to recognize the dispersion situation from meteorological data measured on the site and the applicability of dispersion models are discussed. (orig.) [de

  20. Solitonic Dispersive Hydrodynamics: Theory and Observation

    Science.gov (United States)

    Maiden, Michelle D.; Anderson, Dalton V.; Franco, Nevil A.; El, Gennady A.; Hoefer, Mark A.

    2018-04-01

    Ubiquitous nonlinear waves in dispersive media include localized solitons and extended hydrodynamic states such as dispersive shock waves. Despite their physical prominence and the development of thorough theoretical and experimental investigations of each separately, experiments and a unified theory of solitons and dispersive hydrodynamics are lacking. Here, a general soliton-mean field theory is introduced and used to describe the propagation of solitons in macroscopic hydrodynamic flows. Two universal adiabatic invariants of motion are identified that predict trapping or transmission of solitons by hydrodynamic states. The result of solitons incident upon smooth expansion waves or compressive, rapidly oscillating dispersive shock waves is the same, an effect termed hydrodynamic reciprocity. Experiments on viscous fluid conduits quantitatively confirm the soliton-mean field theory with broader implications for nonlinear optics, superfluids, geophysical fluids, and other dispersive hydrodynamic media.

  1. UFOMOD - atmospheric dispersion and deposition

    International Nuclear Information System (INIS)

    Panitz, H.J.; Matzerath, C.; Paesler-Sauer, J.

    1989-10-01

    The report gives an introduction into the modelling of atmospheric dispersion and deposition which has been implemented in the new program system UFOMOD for assessing the consequences after nuclear accidents. According to the new structure of UFOMOD, different trajectory models with ranges of validity near to the site and at far distances are applied. Emphasis is laid on the description of the segmented plume model MUSEMET and its affilated submodels, being the removal of activity from the cloud by dry and wet deposition, and special effects like plume rise and the behaviour of plumes released into building wakes. In addition, the evaluation of γ-dose correction factors to take account of the finite extent of the radioactive plume in the near range (up to about 20 km) are described. Only brief introductions are given into the principles of the other models available: the puff model RIMPUFF, the long-range puff model MESOS, and the special straight-line Gaussian model ISOLA which are used if low-level long-duration releases are considered. To define starting times of weather sequences and the probabilities of occurrence of these sequences, it is convenient to perform stratified sampling. Therefore, the preprocessing program package METSAM has been developed to perform for generic ACAs a random sampling of weather sequences out off a population of classified weather conditions. The sampling procedure and a detailed input/output (I/O) description is presented and an additional appendix, respectively. A general overview on the I/O structure of MUSEMET as well as a brief user guide to run the KfK version of the MESOS code are also given in the appendix. (orig.) [de

  2. The Braer incident: Dispersion in action

    International Nuclear Information System (INIS)

    Thomas, D.

    1993-01-01

    In January 1993, the tanker Braer foundered in the Shetland Islands and pollution from the cargo of 85,000 tonnes of Gullfaks crude oil was reported almost immediately. The tanker was battered by storm winds and finally broke up, spilling the remainder of its cargo into the bay at Garth's Ness. Dispersants were applied to the oil plumes, assisting the significant natural dispersion. Shoreline protection and cleanup activities included construction of spade dams and sorbent barriers. Oil concentrations in water, air, sediment, and fish were monitored. The sampling program undertaken during the spill period is described. Measured hydrocarbon concentrations in salmon farm areas were not observed to rise above 4 ppM. The high rates of dispersion make the Braer incident worthy of detailed study both in terms of understanding the mechanism of the dispersion process and also in assessing the environmental effects following high dispersed oil concentrations. Estimates of the spill's mass balance are provided for the bay at Garth's Ness, where the highest oil concentrations were observed, and along the 26 km of coastline which received the most significant concentrations of dispersed oil. Contrary to laboratory experiments which showed that the Gullfaks crude would emulsify at the high sea states prevailing at the time, the Braer spill did not emulsify and most of the oil released was dispersed naturally into the water column. It appears that it is most appropriate to model the Braer spill as a spillage of floating or dissolved chemical. 4 refs., 4 figs., 6 tabs

  3. Dispersion cancellation in a triple Laue interferometer

    International Nuclear Information System (INIS)

    Lemmel, Hartmut

    2014-01-01

    The concept of dispersion cancellation has been established in light optics to improve the resolution of interferometric measurements on dispersive media. Odd order dispersion cancellation allows to measure phase shifts without defocusing the interferometer due to wave packet displacements, while even order dispersion cancellation allows to measure time lags without losing resolution due to wave packet spreading. We report that either type of dispersion cancellation can be realized very easily in a triple Laue interferometer. Such interferometers are Mach–Zehnder interferometers based on Bragg diffraction, and are commonly used for neutrons and x-rays. Although the first x-ray interferometer was built nearly five decades ago, the feature of dispersion cancellation hasn't been recognized so far because the concept was hardly known in the neutron and x-ray community. However, it explains right away the surprising decoupling of phase shift and spatial displacement that we have discovered recently in neutron interferometry (Lemmel and Wagh 2010 Phys. Rev. A 82 033626). Furthermore, this article might inspire the light optics community to consider whether a triple Laue interferometer for laser light would be useful and feasible. We explain how dispersion cancellation works in neutron interferometry, and we describe the setup rigorously by solving the Schrödinger equation and by calculating the path integral. We point out, that the latter has to be evaluated with special care since in our setup the beam trajectory moves with respect to the crystal lattice of the interferometer. (paper)

  4. Generalized dispersive wave emission in nonlinear fiber optics.

    Science.gov (United States)

    Webb, K E; Xu, Y Q; Erkintalo, M; Murdoch, S G

    2013-01-15

    We show that the emission of dispersive waves in nonlinear fiber optics is not limited to soliton-like pulses propagating in the anomalous dispersion regime. We demonstrate, both numerically and experimentally, that pulses propagating in the normal dispersion regime can excite resonant dispersive radiation across the zero-dispersion wavelength into the anomalous regime.

  5. Rethinking of the heuristic-analytic dual process theory: a comment on Wada and Nittono (2004) and the reasoning process in the Wason selection task.

    Science.gov (United States)

    Cardaci, Maurizio; Misuraca, Raffaella

    2005-08-01

    This paper raises some methodological problems in the dual process explanation provided by Wada and Nittono for their 2004 results using the Wason selection task. We maintain that the Nittono rethinking approach is weak and that it should be refined to grasp better the evidence of analytic processes.

  6. How I Attend--Not How Well Do I Attend: Rethinking Developmental Frameworks of Attention and Cognition in Autism Spectrum Disorder and Typical Development

    Science.gov (United States)

    Burack, Jacob A.; Russo, Natalie; Kovshoff, Hannah; Palma Fernandes, Tania; Ringo, Jason; Landry, Oriane; Iarocci, Grace

    2016-01-01

    Evidence from the study of attention among persons with autism spectrum disorder (ASD) and typically developing (TD) children suggests a rethinking of the notion that performance inherently reflects disability, ability, or capacity in favor of a more nuanced story that involves an emphasis on styles and biases that reflect real-world attending. We…

  7. Comment on Brent Beal's and Heather Olson Beal's "Rethinking the Market Metaphor: School Choice, the Common Good, and the National Football League"

    Science.gov (United States)

    Bast, Joseph L.

    2013-01-01

    In their article "Rethinking the Market Metaphor: School Choice, the Common Good, and the National Football League," Brent D. Beal and Heather K. Olson Beal (this issue) promise to update some of the arguments made by Jeffrey R. Henig (1994) and add an interesting twist by proposing the National Football League (NFL) as a possible…

  8. Anomalous dispersion enhanced Cerenkov phase-matching

    Energy Technology Data Exchange (ETDEWEB)

    Kowalczyk, T.C.; Singer, K.D. [Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Physics; Cahill, P.A. [Sandia National Labs., Albuquerque, NM (United States)

    1993-11-01

    The authors report on a scheme for phase-matching second harmonic generation in polymer waveguides based on the use of anomalous dispersion to optimize Cerenkov phase matching. They have used the theoretical results of Hashizume et al. and Onda and Ito to design an optimum structure for phase-matched conversion. They have found that the use of anomalous dispersion in the design results in a 100-fold enhancement in the calculated conversion efficiency. This technique also overcomes the limitation of anomalous dispersion phase-matching which results from absorption at the second harmonic. Experiments are in progress to demonstrate these results.

  9. Noise figure of amplified dispersive Fourier transformation

    International Nuclear Information System (INIS)

    Goda, Keisuke; Jalali, Bahram

    2010-01-01

    Amplified dispersive Fourier transformation (ADFT) is a powerful tool for fast real-time spectroscopy as it overcomes the limitations of traditional optical spectrometers. ADFT maps the spectrum of an optical pulse into a temporal waveform using group-velocity dispersion and simultaneously amplifies it in the optical domain. It greatly simplifies spectroscopy by replacing the diffraction grating and detector array in the conventional spectrometer with a dispersive fiber and single-pixel photodetector, enabling ultrafast real-time spectroscopic measurements. Following our earlier work on the theory of ADFT, here we study the effect of noise on ADFT. We derive the noise figure of ADFT and discuss its dependence on various parameters.

  10. Phase noise of dispersion-managed solitons

    International Nuclear Information System (INIS)

    Spiller, Elaine T.; Biondini, Gino

    2009-01-01

    We quantify noise-induced phase deviations of dispersion-managed solitons (DMS) in optical fiber communications and femtosecond lasers. We first develop a perturbation theory for the dispersion-managed nonlinear Schroedinger equation (DMNLSE) in order to compute the noise-induced mean and variance of the soliton parameters. We then use the analytical results to guide importance-sampled Monte Carlo simulations of the noise-driven DMNLSE. Comparison of these results with those from the original unaveraged governing equations confirms the validity of the DMNLSE as a model for many dispersion-managed systems and quantify the increased robustness of DMS with respect to noise-induced phase jitter.

  11. An expert system for dispersion model interpretation

    International Nuclear Information System (INIS)

    Skyllingstad, E.D.; Ramsdell, J.V.

    1988-10-01

    A prototype expert system designed to diagnose dispersion model uncertainty is described in this paper with application to a puff transport model. The system obtains qualitative information from the model user and through an expert-derived knowledge base, performs a rating of the current simulation. These results can then be used in combination with dispersion model output for deciding appropriate evacuation measures. Ultimately, the goal of this work is to develop an expert system that may be operated accurately by an individual uneducated in meteorology or dispersion modeling. 5 refs., 3 figs

  12. Removal of Disperse Blue 56 and Disperse Red 135 dyes from aqueous dispersions by modified montmorillonite nanoclay

    Directory of Open Access Journals (Sweden)

    Ahmadishoar Javad

    2017-01-01

    Full Text Available In this study modified montmorillonite was used as an adsorbent for the removal of two selected disperse dyes i.e., Disperse Blue 56 (DB and Disperse Red 135 (DR from dye dispersions. The adsorption equilibrium data of dyes adsorption were investigated by using Nernst, Freundlich and Langmuir isotherm models. The adsorption kinetics was analyzed by using different models including pseudo-first-order, pseudo-second-order, Elovich and Intraparticle diffusion model. The Freundlich isotherm was found to be the most appropriate model for describing the sorption of the dyes on modified nanoclay. The best fit to the experimental results was obtained by using the pseudo-second-order kinetic equation, which satisfactorily described the process of dye adsorption. Although different kinetic models may control the rate of the adsorption process, the results indicated that the main rate limiting step was the intraparticle diffusion. The results showed that the proposed modified montmorillonite could be used as an effective adsorbent for the removal of disperse dyes even from highly concentrated dispersions.

  13. Dispersion, sorption and photodegradation of petroleum hydrocarbons in dispersant-seawater-sediment systems.

    Science.gov (United States)

    Zhao, Xiao; Liu, Wen; Fu, Jie; Cai, Zhengqing; O'Reilly, S E; Zhao, Dongye

    2016-08-15

    This work examined effects of model oil dispersants on dispersion, sorption and photodegradation of petroleum hydrocarbons in simulated marine systems. Three dispersants (Corexit 9500A, Corexit 9527A and SPC 1000) were used to prepare dispersed water accommodated oil (DWAO). While higher doses of dispersants dispersed more n-alkanes and PAHs, Corexit 9500A preferentially dispersed C11-C20 n-alkanes, whereas Corexit 9527A was more favorable for smaller alkanes (C10-C16), and SPC 1000 for C12-C28 n-alkanes. Sorption of petroleum hydrocarbons on sediment was proportional to TPH types/fractions in the DWAOs. Addition of 18mg/L of Corexit 9500A increased sediment uptake of 2-3 ring PAHs, while higher dispersant doses reduced the uptake, due to micelle-enhanced solubilization effects. Both dispersed n-alkanes and PAHs were susceptible to photodegradation under simulated sunlight. For PAHs, both photodegradation and photo-facilitated alkylation were concurrently taking place. The information can facilitate sounder assessment of fate and distribution of dispersed oil hydrocarbons in marine systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Effects of chemical dispersants on oil physical properties and dispersion. Volume 1

    International Nuclear Information System (INIS)

    Khelifa, A.; Fingas, M.; Hollebone, B.P.; Brown, C.E.; Pjontek, D.

    2007-01-01

    Laboratory and field testing have shown that the dispersion of oil spilled in water is influenced by chemical dispersants via the modification of the interfacial properties of the oil, such as oil-brine interfacial tension (IFT). This study focused on new laboratory experiments that measured the effects on the physical properties and dispersion of oil, with particular reference to the effects of chemical dispersants on IFT and oil viscosity and the subsequent effects on oil droplet formation. Experiments were conducted at 15 degrees C using Arabian Medium, Alaska North Slope and South Louisiana crude and Corexit 9500 and Corexit 9527 chemical dispersants. The dispersants were denser than the 3 oils. The effect of IFT reduction on oil dispersion was measured and showed substantial reduction in the size and enhancement of the concentration of oil droplets in the water column. It was shown that the brine-oil IFT associated with the 3 crudes reduced to less than 3.6 mN/m with the application of the chemical dispersants, even at a low dispersant-to-oil ratio (DOR) value of 1:200. The use of chemical dispersants increased the viscosity of the dispersant-oil mixture up to 40 per cent over the neat crude oil. It was shown that for each mixing condition, an optimum value of DOR exists that provides for maximal dispersant effectiveness. The IFT reaches maximum reduction at optimum DOR. It was suggested that oil spill modelling can be improved with further study of IFT reduction with DOR and variations of critical micelle concentration with the type and solubility of chemical dispersant, oil type and oil to water ratio. 13 refs., 3 tabs., 7 figs

  15. Dispersal Timing: Emigration of Insects Living in Patchy Environments.

    Directory of Open Access Journals (Sweden)

    Milica Lakovic

    Full Text Available Dispersal is a life-history trait affecting dynamics and persistence of populations; it evolves under various known selective pressures. Theoretical studies on dispersal typically assume 'natal dispersal', where individuals emigrate right after birth. But emigration may also occur during a later moment within a reproductive season ('breeding dispersal'. For example, some female butterflies first deposit eggs in their natal patch before migrating to other site(s to continue egg-laying there. How breeding compared to natal dispersal influences the evolution of dispersal has not been explored. To close this gap we used an individual-based simulation approach to analyze (i the evolution of timing of breeding dispersal in annual organisms, (ii its influence on dispersal (compared to natal dispersal. Furthermore, we tested (iii its performance in direct evolutionary contest with individuals following a natal dispersal strategy. Our results show that evolution should typically result in lower dispersal under breeding dispersal, especially when costs of dispersal are low and population size is small. By distributing offspring evenly across two patches, breeding dispersal allows reducing direct sibling competition in the next generation whereas natal dispersal can only reduce trans-generational kin competition by producing highly dispersive offspring in each generation. The added benefit of breeding dispersal is most prominent in patches with small population sizes. Finally, the evolutionary contests show that a breeding dispersal strategy would universally out-compete natal dispersal.

  16. The Dangers of Dispersal of Responsibilities

    Directory of Open Access Journals (Sweden)

    Adriana Schiopoiu Burlea

    2017-05-01

    Full Text Available Taking into account that it is in the nature of the modern corporation that risks are distributed over several agents, we discuss in this paper the organisational behaviour as it results from such dispersal of responsibilities for both the principal and the agent. We explore the hypothesis that dispersal of responsibilities could be the result or a cause of a lack of consensus between the principal and the agent. Our findings suggest that a dispersal of responsibilities has a negative impact on the principal-agent relationship and that it represents a foundation for theoretical and empirical approaches to organisational behaviour. We find that agent perceptions of a dispersal of responsibilities are linked to his/her resistance to the principal’s interests, but this relationship is deeper than was suggested by previous research. However, if the sharing of responsibilities does not run parallel to that, we may have as a result what we call an agency problem.

  17. Adsorption of an anionic dispersant on lignite

    Energy Technology Data Exchange (ETDEWEB)

    Yavuz, R.; Kucukbayrak, S. [Istanbul Technical University, Istanbul (Turkey). Dept. of Chemical Engineering, Chemical & Metallurgical Engineering Faculty

    2001-12-01

    Since coal is not a homogeneous substance but a mixture of carbonaceous materials and mineral matter, it has a variety of surface properties. Therefore, it is not easy to control the properties of coal suspensions by simply adjusting variables, such as pH and/or electrolyte. A chemical agent needs to be added to control the properties of the coal suspensions. The adsorption behavior of an anionic dispersant in the presence of a wetting agent using some Turkish lignite samples was investigated. The effects of dispersant concentration, temperature and pH on the dispersant adsorption were studied systematically, and the experimental results are presented. Pellupur B69 as a dispersant, commercial mixture of formaldehyde condensate sodium salt of naphthalene sulphonic acid, and Texapon N{sub 2}5 as a wetting agent, a sodium lauryl ether sulfate, have been used.

  18. Dispersion engineering in metamaterials and metasurfaces

    Science.gov (United States)

    Li, Xiong; Pu, Mingbo; Ma, Xiaoliang; Guo, Yinghui; Gao, Ping; Luo, Xiangang

    2018-02-01

    Dispersion engineering is essential for spectral utilization in electromagnetic systems. However, it is difficult to manage the dispersions in both natural materials and traditional electromagnetic waveguides since they are tightly related to fine structures of atoms, molecules and causality. The emergence of metamaterials and metasurfaces, which are made of subwavelength inclusions offers tremendous freedom to manipulate the electromagnetic parameters of materials and modes. Here, we review the basic principles, practical applications and recent advancements of the dispersion engineering in metadevices. The contributions of dispersion management in metadevice-based super-resolution imaging/nanolithography systems, planar functional devices, as well as the broadband perfect absorbers/polarization converters are discussed in depth. The challenges faced by this field as well as future developing trends are also presented in the conclusions.

  19. PETROLEUM-COLLECTING AND DISPERSING CHEMICALS FOR ...

    African Journals Online (AJOL)

    Preferred Customer

    Films of petroleum origin reflecting sunlight rays hinder absorption of energy by water necessary for life ... Dispersing chemicals like mechanical clean-up methods have their own place in fighting oil spills. They are ... yellow color, and filtered.

  20. Resuspension parameters for TRAC dispersion model

    International Nuclear Information System (INIS)

    Langer, G.

    1987-01-01

    Resuspension factors for the wind erosion of soil contaminated with plutonium are necessary to run the Rocky Flats Plant Terrain Responsive Atmospheric Code (TRAC). The model predicts the dispersion and resulting population dose due to accidental plutonium releases

  1. Modeling electrical dispersion phenomena in Earth materials

    Directory of Open Access Journals (Sweden)

    D. Patella

    2008-06-01

    Full Text Available It is illustrated that IP phenomena in rocks can be described using conductivity dispersion models deduced as solutions to a 2nd-order linear differential equation describing the motion of a charged particle immersed in an external electrical field. Five dispersion laws are discussed, namely: the non-resonant positive IP model, which leads to the classical Debye-type dispersion law and by extension to the Cole-Cole model, largely used in current practice; the non-resonant negative IP model, which allows negative chargeability values, known in metals at high frequencies, to be explained as an intrinsic physical property of earth materials in specific field cases; the resonant flat, positive or negative IP models, which can explain the presence of peak effects at specific frequencies superimposed on flat, positive or negative dispersion spectra.

  2. Long anterior zonules and pigment dispersion.

    Science.gov (United States)

    Moroi, Sayoko E; Lark, Kurt K; Sieving, Paul A; Nouri-Mahdavi, Kouros; Schlötzer-Schrehardt, Ursula; Katz, Gregory J; Ritch, Robert

    2003-12-01

    To describe pigment dispersion associated with long anterior zonules. Multicenter observational case series. Fifteen patients, seven of whom were treated for glaucoma or ocular hypertension, were identified with long anterior zonules and pigment dispersion. Transmission electron microscopy was performed on one anterior capsule specimen. All patients had anterior zonules that inserted centrally on the lens capsule. Signs of pigment dispersion included corneal endothelial pigmentation, loss of the pupillary ruff, and variable trabecular meshwork pigmentation. Ultrasound biomicroscopy verified the lack of posterior iris insertion and concavity. There was no exfoliation material. Transmission electron microscopy showed zonular lamellae with adherent pigment granules, and no exfoliation material. Long anterior zonules inserted onto the central lens capsule may cause mechanical disruption of the pigment epithelium at the pupillary ruff and central iris leading to pigment dispersion.

  3. Analytic properties of the whistler dispersion function

    International Nuclear Information System (INIS)

    Daniell, G.J.

    1986-01-01

    The analytic properties of the dispersion function of a whistler are investigated in the complex frequency plane. It possesses a pole and a branch point at a frequency equal to the minimum value of the electron gyrofrequency along the path of propagation. An integral equation relates the dispersion function to the distribution of magnetospheric electrons along the path and the solution of this equation is obtained. It is found that the electron density in the equatorial plane is very simply related to the dispersion function. A discussion of approximate formulae to represent the dispersion shows how particular terms can be related to attributes of the electron density distribution, and a new approximate formula is proposed. (author)

  4. Demythologizing the Qur’an Rethinking Revelation Through Naskh al-Qur’an

    Directory of Open Access Journals (Sweden)

    Roslan Abdul-Rahim

    2017-12-01

    Full Text Available This article posits two important claims. One is that naskh al-Qur’an is a real and actual phenomenon. Early sources from the Muslim classical era have been cited to justify this claim. The other is that, the notion and theory of naskh al-Qur’an allow for our rethinking of revelation in Islam. The theoretical discourse of Naskh al-Qur’an hinges on the basic idea and principle of the legal annulment of the law contained in or implied by a particular Qur’anic verse that has since been declared as abrogated. While the Qur’anic theory of abrogation may be about the law, in essence, it is as much about the meanings and dynamics of revelation in Islam. Various processes may be identified with the theory of naskh. Most notably are the processes of “re-revelation” and “revelatory alignment”. Re-revelation, or revelatory revision or realignment is something to be appreciated. These terms imply adaptation. Through highlighting textual instances in the Qur’an, this paper intends to demonstrate that Qur’anic revelation apparently came down not in isolation but in tandem with the interests and altering dynamics of an emerging and developing community. This idea of revelatory adaptation has far reaching consequences. At the theological level, it impacts on the current established notion of the immutability of the Qur’an. It in turn signifies the significance of naskh in determining the direction of fiqh and tafsir, and in revealing to us the theological nature of wahy. At the interpretive and more practical level, it influences the way the law may be understood and applied in Islam. Most importantly, at the philosophical level, it demythologizes the Qur’an. This paper is a preliminary attempt at reassessing the notion of wahy in Islam. It proposes a paradigm shift in the way we look at the Qur’an and the way we understand revelation in Islam.

  5. Feeding people is easy: but we have to re-think the world from first principles.

    Science.gov (United States)

    Tudge, Colin

    2005-09-01

    Agriculture designed to make best use of landscape and to be maximally sustainable would also provide food of the highest nutritional and gastronomic standards, and would inevitably employ a great many people. Thus it would solve the world's food problems, and its principal social problem, at a stroke. But agriculture in practice is designed for a quite different purpose--to generate wealth, in the cause of 'economic growth'. The pressing need is not for more science and technology, but to recognise the true cause of the problems and to re-think priorities. We could all be well fed. Indeed, everyone in the world who is ever likely to be born could be fed to the highest standards of gastronomy as well as of nutrition until humanity itself comes to an end. We already have most of the necessary technique--perhaps all that is needed. We could always do with more excellent science but we need not depend, as we are often told from on high, on the next technological fix. The methods that can provide excellent food would also create a beautiful environment, with plenty of scope for other creatures, and agreeable and stable agrarian economies with satisfying jobs for all. In reality, in absolute contrast, we have created a world in which almost a billion are chronically undernourished; another billion are horribly overnourished, so that obesity and diabetes are epidemic, and rising; a billion live on less than two dollars a day; and a billion live in urban slums--a figure set to increase and probably at least to double over the next half century; while other species are disappearing so fast that biologists speak of mass extinction.

  6. Rethinking blood components and patients: Patient blood management. Possible ways for development in France.

    Science.gov (United States)

    Folléa, Gilles

    2016-01-01

    As any therapeutic means, blood transfusion requires regular evaluation, particularly for its indications, effectiveness and risks. A better awareness of the risks of blood transfusion, the availability of randomized clinical trials, the evolution of the quality of blood components, and the economic constraints shared by all countries, all have led to rethink both transfusion therapy as a whole and the organization of the transfusion chain from donor to recipient. In this context, patient blood management (PBM) appears as an evidence-based, patient centred, multidisciplinary approach, aiming to optimise the care of patients who might need transfusion and consequently the use of blood products. This paper presents updated scientific bases of PBM and the three pillars founding it. As PBM is developing fast in other European countries, this review proposes ways to explore for its development in France. It finally proposes to integrate PBM in a wider and coordinated approach of the blood supply management, with tools to improve the effectiveness and efficiency of the transfusion chain, starting with the needs of the patients and ending with an optimum treatment of the patient, including the appropriate number of blood components of the required quality. A better understanding, implementation and assessment of this coordinated global approach, allowing to adapt donor collections to the patients' needs in compliance with safety requirements for patients and donors, in a coordinated way, will certainly be a major challenge for transfusion medicine in the near future, for the benefit of patients, donors and all other stakeholders involved in the transfusion chain. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  7. Blood, donors and dollars: Rethinking financial sustainability of safe blood services in Tanzania

    Directory of Open Access Journals (Sweden)

    Kahabi Ganka Isangula

    2016-01-01

    Full Text Available Introduction Collection, processing and distribution of safe blood in Tanzania occurs within a free-for-service context, that is, a collection from non-remunerated blood donors and distributing freely to the needy people through health facilities. The safe blood services in the country appear to be crippled with many challenges and cannot meet the demand for blood and its products. As such, a need for rethinking collection methods, financial models and possible mechanisms for donor remuneration is evident. Methods In this paper, we venture on multi-stakeholder meetings and ongoing discussions regarding the internal mechanisms of safe blood transfusion financing. The intent is to offer a perspective on the considerations for self- sustaining safe blood services in the country and the extent to which they may be implemented or not. Results We suggest that despite huge demand, the external donor dependent financing mechanisms for safe blood services in the country are ineffective. Therefore, we discuss two potential ‘internal’ financing mechanisms that have been identified in recent shareholders forums 1 introducing a blood processing fee accompanied by policy change to allow direct charging of either recipients or hospitals or 2 influencing the introduction of ‘blood services’ within the current insurance schemes. Conclusion We conclude that there is a need for constructing alternative financial mechanisms to sustain the demand of safe blood in the country. We discuss two cost recovery mechanisms, blood processing fee and insurance schemes; however, warning is noted that their implementation warrants structural adjustments, massive community sensitization and optimum stakeholder engagement to maximize acceptability within the country.

  8. Rethinking the Role of Grey Literature in the Fourth Industrial Revolution

    International Nuclear Information System (INIS)

    Savić, Dobrica

    2018-01-01

    The world is at the dawn of a new industrial revolution that will fundamentally change the way we live and work. Many consider this the Fourth Industrial Revolution (4IR). While the First Industrial Revolution (1IR) mechanized production using water and steam power, the second one brought mass production using electric power, and the third one was characterized by automation and digitization, mainly using electronics and information technology. The 4IR is building upon the third one, but the difference, and its main contribution, is the fusion of technologies that are blurring the lines between the physical, digital, and biological worlds. This is further enhanced by the emerging progress of technology in fields such as quantum computing, machine learning, artificial intelligence, robotics, virtual assistants, the Internet of Things, self-driving cars, drones, 3-D printing, nanotechnology, biotechnology, traffic and security monitoring systems, and renewable energy. This paper examines the potential impact of the emerging 4IR on grey literature (GL) and is based on analysis of the most prevalent current trends and developments in “cyber-physical systems” that connect machines, computers and people. It will examine the need to rethink the definition of GL, its creation and publication types, processing, sustainability and usability. Given the magnitude of the potential impact of the 4IR on GL, the question is what challenges the 4IR will pose to GL managers. One could assume that the acquisition of new knowledge and skills, and the revamping of existing processes and methods will be necessary. Becoming aware of this new phenomenon is only the beginning. It needs to be followed up by professional development and adequate training. Finally, the job of GL professionals will be to promote and publicize the usefulness and importance of GL, not only in their daily work, but also in research and science. (author)

  9. SANS observations on weakly flocculated dispersions

    DEFF Research Database (Denmark)

    Mischenko, N.; Ourieva, G.; Mortensen, K.

    1997-01-01

    Structural changes occurring in colloidal dispersions of poly-(methyl metacrylate) (PMMA) particles, sterically stabilized with poly-(12-hydroxystearic acid) (PHSA), while varying the solvent quality, temperature and shear rate, are investigated by small-angle neutron scattering (SANS......). For a moderately concentrated dispersion in a marginal solvent the transition on cooling from the effective stability to a weak attraction is monitored, The degree of attraction is determined in the framework of the sticky spheres model (SSM), SANS and rheological results are correlated....

  10. Phonon dispersion relations for caesium thiocyanate

    International Nuclear Information System (INIS)

    Irving, M.A.; Smith, T.F.; Elcombe, M.M.

    1984-01-01

    Room temperature phonon dispersion relations for frequencies below 2 THz have been measured, along the three orthorhombic axes and selected diagonal directions by neutron inelastic scattering, for caesium thiocyanate. These curves, which represent 13 acoustic modes and 11 optic modes of vibration, do not agree with the dispersion behaviour calculated from the rigid-ion model developed by Ti and Ra to describe their Raman scattering observations

  11. Modelling of pollution dispersion in atmosphere

    International Nuclear Information System (INIS)

    Borysiewicz, M.; Stankiewicz, R.

    1994-01-01

    The paper contains the review of the mathematical foundation of atmospheric dispersion models. The atmospheric phenomena relevant to atmospheric dispersion model are discussed. In particular the parametrization of processes with time and space scales smaller than numerical grid size, limited by available computer power, is presented. The special attention was devoted to similarity theory and parametrization of boundary layer. The numerical methods are analysed and the drawbacks of the method are presented. (author). 99 refs, 15 figs, 3 tabs

  12. Employment Effects of Spatial Dispersal of Refugees

    DEFF Research Database (Denmark)

    Damm, Anna Piil; Rosholm, Michael

    Spatial dispersal policies may influence labour market integration of refugees through two mechanisms. First, it may affect the local job offer arrival rate, and second, it may affect place utility. We investigate the second mechanism theoretically by formulating a partial search model in which a...... due to large local reservation wage effects. We investigate both mechanisms empirically and test the predictions of the theoretical model by evaluating the employment effects of the Danish spatial dispersal policy carried out 1986-1998....

  13. Employment Effects of Spatial Dispersal of Refugees

    OpenAIRE

    Damm, Anna Piil; Rosholm, Michael

    2005-01-01

    We argue that spatial dispersal influences labour market assimilation of refugees through two mechanisms: first, the local job offer arrival rate and, second, place utility. Our partial search model with simultaneous job and residential location search predicts that the reservation wage for local jobs decreases with place utility. We argue that spatial dispersal decreases average place utility of refugees which decreases the transition rate into first job due to large local reservation wages....

  14. URANIUM BISMUTHIDE DISPERSION IN MOLTEN METAL

    Science.gov (United States)

    Teitel, R.J.

    1959-10-27

    The formation of intermetallic bismuth compounds of thorium or uranium dispersed in a liquid media containing bismuth and lead is described. A bismuthide of uranium dispersed in a liquid metal medium is formed by dissolving uranium in composition of lead and bismuth containing less than 80% lead and lowering the temperature of the composition to a temperature below the point at which the solubility of uranium is exceeded and above the melting point of the composition.

  15. Dispersed-phase catalysis in coal liquefaction

    International Nuclear Information System (INIS)

    Utz, B.R.; Cugini, A.V.; Frommell, E.A.

    1990-01-01

    This paper reports that the specific reaction (activation) conditions for the conversion of catalyst precursors to unsupported catalyst have a direct effect on the catalytic activity and dispersion. The importance of reaction intermediates in decomposition of ammonium heptamolybdate and ammonium tetrathiomolybdate, and the sensitivity of these intermediates to reaction conditions, were studied in coal liquefaction systems. Recent results indicate that optimization of activation conditions facilitates the formation of a highly dispersed and active form of molybdenum disulfide for coal liquefaction. The use of the catalyst precursors ammonium heptamolybdate, ammonium tetrathiomolybdate, and molybdenum trisulfide for the conversion of coal to soluble products will be discussed. The use of an unsupported dispersed-phase catalyst for direct coal liquefaction is not a novel concept and has been employed in may studies with varying success. Dispersed-phase catalysts soluble and oil-soluble salts, and as finely divided powders. While some methods of catalyst introduction give higher dispersion of the catalyst and greater activity for the liquefaction of coal, all of the techniques allow the formation of a finely dispersed inorganic phase

  16. Estimate of dispersion in an unsaturated aquifer

    Science.gov (United States)

    Stephenson, D.; De Jesus, A. S. M.

    1985-10-01

    The Nuclear Development Corporation of South Africa (Pty) Ltd. (NUCOR) is constructing a low-level radioactive waste disposal site near Springbok in Namaqualand, an arid region to the west of South Africa. A groundwater model was developed which required site-specific data and this work describes procedures developed to assess the dispersivity of the soil in the vicinity of the proposed site. Preliminary laboratory tests, carried out using a sodium chloride solution, indicated the order of magnitude of the dispersivity for saturated soil at various levels. This enabled site tests to be designed. The site tests were done by injecting a pulse of scandium-46 into a hole and monitoring the displacement of the radioactive cloud as it moved down under gravity and spread laterally. A mathematical model was developed to predict the behaviour of the cloud and calibration of the model yielded vertical and horizontal dispersivities. The dispersion of radioactivity at the cloud front was assumed to occur in unsaturated medium while the continuously injected water behind the radioactivity was assumed to disperse in a saturated medium. Thus monitoring the concentration of both yielded approximate values for the effective dispersivities in unsaturated and saturated media.

  17. Spatially varying dispersion to model breakthrough curves.

    Science.gov (United States)

    Li, Guangquan

    2011-01-01

    Often the water flowing in a karst conduit is a combination of contaminated water entering at a sinkhole and cleaner water released from the limestone matrix. Transport processes in the conduit are controlled by advection, mixing (dilution and dispersion), and retention-release. In this article, a karst transport model considering advection, spatially varying dispersion, and dilution (from matrix seepage) is developed. Two approximate Green's functions are obtained using transformation of variables, respectively, for the initial-value problem and for the boundary-value problem. A numerical example illustrates that mixing associated with strong spatially varying conduit dispersion can cause strong skewness and long tailing in spring breakthrough curves. Comparison of the predicted breakthrough curve against that measured from a dye-tracing experiment between Ames Sink and Indian Spring, Northwest Florida, shows that the conduit dispersivity can be as large as 400 m. Such a large number is believed to imply strong solute interaction between the conduit and the matrix and/or multiple flow paths in a conduit network. It is concluded that Taylor dispersion is not dominant in transport in a karst conduit, and the complicated retention-release process between mobile- and immobile waters may be described by strong spatially varying conduit dispersion. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.

  18. Juvenile dispersal in Calomys venustus (Muridae: Sigmodontinae)

    Science.gov (United States)

    Priotto, José; Steinmann, Andrea; Provensal, Cecilia; Polop, Jaime

    2004-05-01

    Both spacing behaviour and dispersal movement are viewed as hierarchical processes in which the effects may be expressed at spatial scale. This research was carried out to examine the hypothesis that the presence of parents promotes the dispersal of juveniles from their natal nest and their father or mother home-range, in Calomys venustus.The study was carried out in four 0.25 ha fences (two controls and two experimentals), in a natural pasture. This study had two periods: Father Removal (FR) (August and December 1997; year one) and Mother Removal (MR) (August 1998 and January 1999; year two). For the FR treatment fathers were removed after juveniles were born, but in the MR treatment mothers were removed after the juveniles were weaned. The effect of parents on the dispersal distance of juveniles was analysed with respect to their natal nest and their mother and father home-range. Dispersal distance from the nest of C. venustus was independent of either male or female parent. Juveniles were more dispersing in relation to the centre of activity of their mothers than to that of their fathers, and females were more dispersing than males. Female juveniles overlap their home-range with their parents less than male juveniles do. The differences observed between female and male juveniles would be related to their different sexual maturation times, as well as to the female territoriality.

  19. Magnon dispersion in thin magnetic films

    International Nuclear Information System (INIS)

    Balashov, T; Wulfhekel, W; Buczek, P; Sandratskii, L; Ernst, A

    2014-01-01

    Although the dispersion of magnons has been measured in many bulk materials, few studies deal with the changes in the dispersion when the material is in the form of a thin film, a system that is of interest for applications. Here we review inelastic tunneling spectroscopy studies of magnon dispersion in Mn/Cu 3 Au(1 0 0) and present new studies on Co and Ni thin films on Cu(1 0 0). The dispersion in Mn and Co films closely follows the dispersion of bulk samples with negligible dependence on thickness. The lifetime of magnons depends slightly on film thickness, and decreases considerably as the magnon energy increases. In Ni/Cu(1 0 0) films the thickness dependence of dispersion is much more pronounced. The measurements indicate a considerable mode softening for thinner films. Magnon lifetimes decrease dramatically near the edge of the Brillouin zone due to a close proximity of the Stoner continuum. The experimental study is supported by first-principles calculations. (paper)

  20. Magnon dispersion in thin magnetic films.

    Science.gov (United States)

    Balashov, T; Buczek, P; Sandratskii, L; Ernst, A; Wulfhekel, W

    2014-10-01

    Although the dispersion of magnons has been measured in many bulk materials, few studies deal with the changes in the dispersion when the material is in the form of a thin film, a system that is of interest for applications. Here we review inelastic tunneling spectroscopy studies of magnon dispersion in Mn/Cu3Au(1 0 0) and present new studies on Co and Ni thin films on Cu(1 0 0). The dispersion in Mn and Co films closely follows the dispersion of bulk samples with negligible dependence on thickness. The lifetime of magnons depends slightly on film thickness, and decreases considerably as the magnon energy increases. In Ni/Cu(1 0 0) films the thickness dependence of dispersion is much more pronounced. The measurements indicate a considerable mode softening for thinner films. Magnon lifetimes decrease dramatically near the edge of the Brillouin zone due to a close proximity of the Stoner continuum. The experimental study is supported by first-principles calculations.

  1. Surgical Management of Iatrogenic Pigment Dispersion Glaucoma.

    Science.gov (United States)

    Mierlo, Camille Van; Pinto, Luis Abegão; Stalmans, Ingeborg

    2015-01-01

    Iatrogenic pigment dispersion syndrome generally originates from a repetitive, mechanical trauma to the pigmented posterior epithelium of the iris. This trauma can arise after intraocular surgery, most commonly due to an abnormal contact between the intraocular lens (IOL) and the iris. Whether surgical removal of this primary insult can lead to a successful intraocular pressure (IOP) control remains unclear. Case-series. Patients with IOP elevation and clinical signs of pigment dispersion were screened for a diagnosis of iatrogenic IOL-related pigment dispersion. Three patients in which the IOL or the IOL-bag complex caused a pigment dispersion through a repetitive iris chafing were selected. In two cases, replacement of a sulcus-based single-piece IOL (patient 1) or a sub-luxated in-the-bag IOL (patient 2) by an anterior-chamber (AC) iris-fixed IOL led to a sustained decrease in IOP. In the third case, extensive iris atrophy and poor anatomical AC parameters for IOL implantation precluded further surgical intervention. IOL-exchange appears to be a useful tool in the management of iatrogenic pigment dispersion glaucoma due to inappropriate IOL implantation. This cause-oriented approach seems to be effective in controlling IOP, but should be offered only if safety criteria are met. How to cite this article: Van Mierlo C, Abegao Pinto L, Stalmans I. Surgical Management of Iatrogenic Pigment Dispersion Glaucoma. J Curr Glaucoma Pract 2015;9(1):28-32.

  2. Rheological Behavior of Bentonite-Polyester Dispersions

    Science.gov (United States)

    Abu-Jdayil, Basim; Al-Omari, Salah Addin

    2013-07-01

    The rheological behavior of a bentonite clay dispersed in unsaturated polyester was investigated. The effects of the solid content and particle size on the steady and transient rheological properties of the dispersions were studied. In addition, two types of bentonite with different Na+/Ca+2 ratio were used in this study. The Herschel-Bulkley and the Weltman models were used to describe the apparent viscosity of the bentonite-polyester composite in relation to the shear rate and shearing time. The bentonite-polyester dispersions were found to exhibit both Newtonian and non-Newtonian behavior. The transition from a Newtonian to a Bingham plastic and then to a shear-thinning material with a yield stress was found to depend on the solid concentration, the particle size, and the type of bentonite. At a low solid content, the apparent viscosity of the bentonite dispersion increased linearly with solid concentration. But a dramatic increase in the apparent viscosity beyond a solid content of 20 wt.% was observed. On the other hand, a thixotropic behavior was detected in bentonite-polyester dispersions with a high solid content and a low particle size. However, this behavior was more pronounced in dispersions with a high Na+/Ca+2 ratio.

  3. Cefuroxime axetil solid dispersions prepared using solution enhanced dispersion by supercritical fluids.

    Science.gov (United States)

    Jun, Seoung Wook; Kim, Min-Soo; Jo, Guk Hyun; Lee, Sibeum; Woo, Jong Soo; Park, Jeong-Sook; Hwang, Sung-Joo

    2005-12-01

    Cefuroxime axetil (CA) solid dispersions with HPMC 2910/PVP K-30 were prepared using solution enhanced dispersion by supercritical fluids (SEDS) in an effort to increase the dissolution rate of poorly water-soluble drugs. Their physicochemical properties in solid state were characterized by differential scanning calorimeter (DSC), powder X-ray diffraction (PXRD), Fourier transform infrared spectrometry (FT-IR) and scanning electron microscopy. No endothermic and characteristic diffraction peaks corresponding to CA were observed for the solid dispersions in DSC and PXRD. FTIR analysis demonstrated the presence of intermolecular hydrogen bonds between CA and HPMC 2910/PVP K-30 in solid dispersions, resulting in the formation of amorphous or non-crystalline CA. Dissolution studies indicated that the dissolution rates were remarkably increased in solid dispersions compared with those in the physical mixture and drug alone. In conclusion, an amorphous or non-crystalline CA solid dispersion prepared using SEDS could be very useful for the formulation of solid dosage forms.

  4. Dispersal kernel estimation: A comparison of empirical and modelled particle dispersion in a coastal marine system

    Science.gov (United States)

    Hrycik, Janelle M.; Chassé, Joël; Ruddick, Barry R.; Taggart, Christopher T.

    2013-11-01

    Early life-stage dispersal influences recruitment and is of significance in explaining the distribution and connectivity of marine species. Motivations for quantifying dispersal range from biodiversity conservation to the design of marine reserves and the mitigation of species invasions. Here we compare estimates of real particle dispersion in a coastal marine environment with similar estimates provided by hydrodynamic modelling. We do so by using a system of magnetically attractive particles (MAPs) and a magnetic-collector array that provides measures of Lagrangian dispersion based on the time-integration of MAPs dispersing through the array. MAPs released as a point source in a coastal marine location dispersed through the collector array over a 5-7 d period. A virtual release and observed (real-time) environmental conditions were used in a high-resolution three-dimensional hydrodynamic model to estimate the dispersal of virtual particles (VPs). The number of MAPs captured throughout the collector array and the number of VPs that passed through each corresponding model location were enumerated and compared. Although VP dispersal reflected several aspects of the observed MAP dispersal, the comparisons demonstrated model sensitivity to the small-scale (random-walk) particle diffusivity parameter (Kp). The one-dimensional dispersal kernel for the MAPs had an e-folding scale estimate in the range of 5.19-11.44 km, while those from the model simulations were comparable at 1.89-6.52 km, and also demonstrated sensitivity to Kp. Variations among comparisons are related to the value of Kp used in modelling and are postulated to be related to MAP losses from the water column and (or) shear dispersion acting on the MAPs; a process that is constrained in the model. Our demonstration indicates a promising new way of 1) quantitatively and empirically estimating the dispersal kernel in aquatic systems, and 2) quantitatively assessing and (or) improving regional hydrodynamic

  5. Design and development of a dust dispersion chamber to quantify the dispersibility of rock dust.

    Science.gov (United States)

    Perera, Inoka E; Sapko, Michael J; Harris, Marcia L; Zlochower, Isaac A; Weiss, Eric S

    2016-01-01

    Dispersible rock dust must be applied to the surfaces of entries in underground coal mines in order to inert the coal dust entrained or made airborne during an explosion and prevent propagating explosions. 30 CFR. 75.2 states that "… [rock dust particles] when wetted and dried will not cohere to form a cake which will not be dispersed into separate particles by a light blast of air …" However, a proper definition or quantification of "light blast of air" is not provided. The National Institute for Occupational Safety and Health (NIOSH) has, consequently, designed a dust dispersion chamber to conduct quantitative laboratory-scale dispersibility experiments as a screening tool for candidate rock dusts. A reproducible pulse of air is injected into the chamber and across a shallow tray of rock dust. The dust dispersed and carried downwind is monitored. The mass loss of the dust tray and the airborne dust measurements determine the relative dispersibility of the dust with respect to a Reference rock dust. This report describes the design and the methodology to evaluate the relative dispersibility of rock dusts with and without anti-caking agents. Further, the results of this study indicate that the dispersibility of rock dusts varies with particle size, type of anti-caking agent used, and with the untapped bulk density. Untreated rock dusts, when wetted and dried forming a cake that was much less dispersible than the reference rock dust used in supporting the 80% total incombustible content rule.

  6. The dispersion of SWCNTs treated by coupling and dispersing agents in fiber reinforced polymer composities

    Science.gov (United States)

    Duan, Yuexin; Yuan, Lu; Zhao, Yan; Guan, Fengxia

    2007-07-01

    It is an obstacle issue for Carbon nanotubes (CNTs) applied in fiber reinforced polymer composites that CNTs is dispersed in nano-level, particularly for single-wall Carbon nanotubes (SWCNTs). In this paper, SWCNTs were treated by the coupling agent like volan and dispersing agent as BYK to improve the dispersion in the Glass Fiber/Epoxy composites. The result of dispersion of SWCNTs in composites was observed by Scanning electron microscopy (SEM). Then the Glass Transition Temperature (Tg) of these kinds of composites with treated and untreated SWCNTs were obtained by Dynamic Mechanical Thermal Analysis (DMTA). Moreover, the bending properties of these composites were tested.

  7. Modeling of corium dispersion in DCH accidents

    International Nuclear Information System (INIS)

    Wu, Q.

    1996-01-01

    A model that governs the dispersion process in the direct containment heating (DCH) reactor accident scenario is developed by a stepwise approach. In this model, the whole transient is subdivided into four phases with an isothermal assumption. These are the liquid and gas discharge, the liquid film flow in the cavity before gas blowdown, the liquid and gas flow in the cavity with droplet entrainment, and the liquid transport and re-entrainment in the subcompartment. In each step, the dominant driving mechanisms are identified to construct the governing equations. By combining all the steps together, the corium dispersion information is obtained in detail. The key parameters are predicted quantitatively. These include the fraction of liquid that flows out of the cavity before gas blowdown, the dispersion fraction and the mean droplet diameter in the cavity, the cavity pressure rise due to the liquid friction force, and the dispersion fractions in the containment via different paths. Compared with the data of the 1:10 scale experiments carried out at Purdue University, fairly good agreement is obtained. A stand-alone prediction of the corium dispersion under prototypic Zion reactor conditions is carried out by assuming an isothermal process without chemical reactions. (orig.)

  8. Atmospheric dispersion models of radioactivity releases

    International Nuclear Information System (INIS)

    Oza, R.B.

    2016-01-01

    In view of the rapid industrialization in recent time, atmospheric dispersion models have become indispensible 'tools' to ensure that the effects of releases are well within the acceptable limits set by the regulatory authority. In the case of radioactive releases from the nuclear facility, though negligible in quantity and many a times not even measurable, it is required to demonstrate the compliance of these releases to the regulatory limits set by the regulatory authority by carrying out radiological impact assessment. During routine operations of nuclear facility, the releases are so low that environmental impact is usually assessed with the help of atmospheric dispersion models as it is difficult to distinguish negligible contribution of nuclear facility to relatively high natural background radiation. The accidental releases from nuclear facility, though with negligible probability of occurrence, cannot be ruled out. In such cases, the atmospheric dispersion models are of great help to emergency planners for deciding the intervention actions to minimize the consequences in public domain and also to workout strategies for the management of situation. In case of accidental conditions, the atmospheric dispersion models are also utilized for the estimation of probable quantities of radionuclides which might have got released to the atmosphere. Thus, atmospheric dispersion models are an essential tool for nuclear facility during routine operation as well as in the case of accidental conditions

  9. Does Environmental Knowledge Inhibit Hominin Dispersal?

    Science.gov (United States)

    Wren, Colin D; Costopoulos, Andre

    2015-07-01

    We investigated the relationship between the dispersal potential of a hominin population, its local-scale foraging strategies, and the characteristics of the resource environment using an agent-based modeling approach. In previous work we demonstrated that natural selection can favor a relatively low capacity for assessing and predicting the quality of the resource environment, especially when the distribution of resources is highly clustered. That work also suggested that the more knowledge foraging populations had about their environment, the less likely they were to abandon the landscape they know and disperse into novel territory. The present study gives agents new individual and social strategies for learning about their environment. For both individual and social learning, natural selection favors decreased levels of environmental knowledge, particularly in low-heterogeneity environments. Social acquisition of detailed environmental knowledge results in crowding of agents, which reduces available reproductive space and relative fitness. Agents with less environmental knowledge move away from resource clusters and into areas with more space available for reproduction. These results suggest that, rather than being a requirement for successful dispersal, environmental knowledge strengthens the ties to particular locations and significantly reduces the dispersal potential as a result. The evolved level of environmental knowledge in a population depends on the characteristics of the resource environment and affects the dispersal capacity of the population.

  10. Oak Dispersal Syndromes: Do Red and White Oaks Exhibit Different Dispersal Srategies?

    Science.gov (United States)

    Michael Steele; Peter Smallwood; William B. Terzaghi; John E. Carlson; Thomas conteras; Amy McEuen

    2004-01-01

    We provide an overview of the ecological and evolutionary interactions between oaks and several of their dispersal agents, and review a series of studies that demonstrate how various acorn characteristics affect feeding and caching decisions of these animals, which in turn may influence oak dispersal and establishment. We demonstrate that acorns of red oak species show...

  11. Tailoring Dispersion properties of photonic crystal waveguides by topology optimization

    DEFF Research Database (Denmark)

    Stainko, Roman; Sigmund, Ole

    2007-01-01

    based design updates. The goal of the optimization process is to come up with slow light, zero group velocity dispersion photonic waveguides or photonic waveguides with tailored dispersion properties for dispersion compensation purposes. Two examples concerning reproduction of a specific dispersion...

  12. Measurement of small dispersion values in optical components

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Liu, Fenghai; Pedersen, Rune Johan Skullerud

    1999-01-01

    It is reported that small dispersion values in optical components can be measured using the RF modulation method originally restricted to large dispersions. Using a constant dispersion offset, arbitrarily small dispersion values can be measured with a resolution as good as 1.2 ps/nm....

  13. Natal dispersal and personalities in great tits (Parus major)

    NARCIS (Netherlands)

    Dingemanse, NJ; Both, C; van Noordwijk, AJ; Rutten, AL; Drent, PJ; Noordwijk, Arie J. van; Drent, Piet J.

    2003-01-01

    Dispersal is a major determinant of the dynamics and genetic structure of populations, and its consequences depend not only on average dispersal rates and distances, but also on the characteristics of dispersing and philopatric individuals. We investigated whether natal dispersal correlated with a

  14. Dynamics of Dispersive Wave Generation in Gas-Filled Photonic Crystal Fiber with the Normal Dispersion

    Directory of Open Access Journals (Sweden)

    Zhixiang Deng

    2017-01-01

    Full Text Available The absence of Raman and unique pressure-tunable dispersion is the characteristic feature of gas-filled photonic crystal fiber (PCF, and its zero dispersion points can be extended to the near-infrared by increasing gas pressure. The generation of dispersive wave (DW in the normal group velocity dispersion (GVD region of PCF is investigated. It is demonstrated that considering the self-steepening (SS and introducing the chirp of the initial input pulse are two suitable means to control the DW generation. The SS enhances the relative average intensity of blue-shift DW while weakening that of red-shift DW. The required propagation distance of DW emission is markedly varied by introducing the frequency chirp. Manipulating DW generation in gas-filled PCF by the combined effects of either SS or chirp and three-order dispersion (TOD provides a method for a concentrated transfer of energy into the targeted wavelengths.

  15. Employment effects of spatial dispersal of refugees

    DEFF Research Database (Denmark)

    Damm, Anna Piil; Rosholm, Michael

    2010-01-01

    Refugees subjected to a spatial dispersal tend to be assigned to a location outside the immigrant-dense cities. We argue that such locations are associated with low place utility. Our partial equilibrium search model with simultaneous job and residential location search predicts that the reservat......Refugees subjected to a spatial dispersal tend to be assigned to a location outside the immigrant-dense cities. We argue that such locations are associated with low place utility. Our partial equilibrium search model with simultaneous job and residential location search predicts...... that the reservation wage for local jobs decreases with place utility. We test the theoretical prediction by estimating the effects of characteristics of the location of assignment on the transition rate into the first job. Our sample is male refugees aged 30-59 who were subjected to the Danish spatial dispersal...

  16. Sphagnum moss disperses spores with vortex rings.

    Science.gov (United States)

    Whitaker, Dwight L; Edwards, Joan

    2010-07-23

    Sphagnum spores, which have low terminal velocities, are carried by turbulent wind currents to establish colonies many kilometers away. However, spores that are easily kept aloft are also rapidly decelerated in still air; thus, dispersal range depends strongly on release height. Vascular plants grow tall to lift spores into sufficient wind currents for dispersal, but nonvascular plants such as Sphagnum cannot grow sufficiently high. High-speed videos show that exploding capsules of Sphagnum generate vortex rings to efficiently carry spores high enough to be dispersed by turbulent air currents. Spores launched ballistically at similar speeds through still air would travel a few millimeters and not easily reach turbulent air. Vortex rings are used by animals; here, we report vortex rings generated by plants.

  17. Mechanical dispersion in fractured crystalline rock systems

    International Nuclear Information System (INIS)

    Lafleur, D.W.; Raven, K.G.

    1986-12-01

    This report compiles and evaluates the hydrogeologic parameters describing the flow of groundwater and transport of solutes in fractured crystalline rocks. This report describes the processes of mechanical dispersion in fractured crystalline rocks, and compiles and evaluates the dispersion parameters determined from both laboratory and field tracer experiments. The compiled data show that extrapolation of the reliable test results performed over intermediate scales (10's of m and 10's to 100's of hours) to larger spatial and temporal scales required for performance assessment of a nuclear waste repository in crystalline rock is not justified. The reliable measures of longitudinal dispersivity of fractured crystalline rock are found to range between 0.4 and 7.8 m

  18. Taylor dispersion in wind-driven current

    Science.gov (United States)

    Li, Gang; Wang, Ping; Jiang, Wei-Quan; Zeng, Li; Li, Zhi; Chen, G. Q.

    2017-12-01

    Taylor dispersion associated with wind-driven currents in channels, shallow lakes and estuaries is essential to hydrological environmental management. For solute dispersion in a wind-driven current, presented in this paper is an analytical study of the evolution of concentration distribution. The concentration moments are intensively derived for an accurate presentation of the mean concentration distribution, up to the effect of kurtosis. The vertical divergence of concentration is then deduced by Gill's method of series expansion up to the fourth order. Based on the temporal evolution of the vertical concentration distribution, the dispersion process in the wind-driven current is concretely characterized. The uniform shear leads to a special symmetrical distribution of mean concentration free of skewness. The non-uniformity of vertical concentration is caused by convection and smeared out gradually by the effect of diffusion, but fails to disappear even at large times.

  19. Dispersion self-energy of the electron

    International Nuclear Information System (INIS)

    Hawton, M.

    1991-01-01

    Electron mass renormalization and the Lamb shift have been investigated using the dispersion self-energy formalism. If shifts of both the electromagnetic field and quantum-mechanical transitions frequencies are considered, absorption from the electromagnetic field is canceled by emission due to atomic fluctuations. The frequencies of all modes are obtained from the self-consistency condition that the field seen by the electron is the same as the field produced by the expectation value of current. The radiation present can thus be viewed as arising from emission and subsequent reabsorption by matter. As developed here, the numerical predictions of dispersion theory are identical to those of quantum electrodynamics. The physical picture implied by dispersion theory is discussed in the context of semiclassical theories and quantum electrodynamics

  20. Glass transition in soft-sphere dispersions

    International Nuclear Information System (INIS)

    RamIrez-Gonzalez, P E; Medina-Noyola, M

    2009-01-01

    The concept of dynamic equivalence among mono-disperse soft-sphere fluids is employed in the framework of the self-consistent generalized Langevin equation (SCGLE) theory of colloid dynamics to calculate the ideal glass transition phase diagram of model soft-sphere colloidal dispersions in the softness-concentration state space. The slow dynamics predicted by this theory near the glass transition is compared with available experimental data for the decay of the intermediate scattering function of colloidal dispersions of soft-microgel particles. Increasing deviations from this simple scheme occur for increasingly softer potentials, and this is studied here using the Rogers-Young static structure factor of the soft-sphere systems as the input of the SCGLE theory, without assuming a priori the validity of the equivalence principle above.

  1. Training for Internationalization through Domestic Geographical Dispersion

    DEFF Research Database (Denmark)

    Santangelo, Grazia D.; Stucchi, Tamara

    Traditionally created to deal with the unfriendly domestic environment, business groups (BGs) are increasingly internationalizing. However, how BGs can reconcile their strictly domestic orientation with an international dimension still remains an open question. Drawing on arguments from...... organizational learning, we seek to solve this puzzle in relation to the internationalization of Indian BGs. In particular, we argue that in heterogeneous domestic emerging markets BG’s geographical dispersion across sub-national states provides training for internationalization. To internationalize successfully......, BGs need to develop the capability of managing geographically dispersed units in institutional heterogeneous contexts. Domestic geographical dispersion would indeed help the BG dealing with different regulations, customers and infrastructures. However, there is less scope for such training as BGs...

  2. Dispersal behavior of yellowjacket (Vespula germanica) queens.

    Science.gov (United States)

    Masciocchi, Maité; Martinez, Andrés S; Pereira, Ana J; Villacide, José M; Corley, Juan C

    2018-02-01

    Understanding the factors that affect animal dispersal behavior is important from both fundamental and applied perspectives. Dispersal can have clear evolutionary and ecological consequences, but for nonnative insect pests, dispersal capacity can also help to explain invasion success. Vespula germanica is a social wasp that, in the last century, has successfully invaded several regions of the world, showing one of the highest spread rates reported for a nonnative insect. In contrast with nonsocial wasps, in social species, queens are responsible for population redistribution and spread, as workers are sterile. For V. germanica, it has been observed that queen flight is limited to 2 distinct periods: early autumn, when new queens leave the nest to mate and find sheltered places in which to hibernate, and spring when new colonies are founded. Our aim was to study the flight behavior of V. germanica queens by focusing on the different periods in which dispersal occurs, characterizing as well the potential contribution of queen flight (i.e., distance) to the observed geographical spread. Our results suggest that the distances flown by nonoverwintered queens is greater than that flown by overwintered individuals, suggesting that the main queen dispersal events would occur before queens enter hibernation. This could relate to a behavioral trait of the queens to avoid the inbreeding with related drones. Additionally, given the short distances flown and remarkable geographical spread observed, we provide evidence showing that queen dispersal by flight is likely to contribute proportionately less to population spread than human-aided factors. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  3. Familial occurrence of pigment dispersion syndrome.

    Science.gov (United States)

    Bovell, A M; Damji, K F; Dohadwala, A A; Hodge, W G; Allingham, R R

    2001-02-01

    Pigment dispersion syndrome affects up to 4% of the white population. It is characterized by the presence of transillumination defects, Krukenberg's spindle and dense trabecular meshwork pigmentation. Open-angle glaucoma will develop in as many as 50% of affected patients. In this study we describe the familial occurrence of pigment dispersion syndrome in six North American pedigrees and the phenotypic characteristics with respect to pigment dispersion syndrome and glaucoma. Probands with pigment dispersion syndrome were identified in glaucoma clinics at university eye centres in Ottawa and Durham, NC. Families with two or more affected members were evaluated. All willing members in each family underwent a thorough clinical examination and were classified as affected with pigment dispersion syndrome, suspect or unaffected. The previous medical records were reviewed to obtain the past medical and ocular history, including risk factors for glaucoma. All six families are white. Three families show at least two generations of affected members. Of the 43 subjects examined 58% were women. All 14 affected members showed moderate to heavy trabecular meshwork pigmentation and either Krukenberg's spindle or transillumination defects. The affected members were also considerably more myopic (mean spherical equivalent for the right eye -4.72 dioptres) than the suspect group or the unaffected group (mean spherical equivalent -0.79 D and +1.19 D respectively) (p pigment dispersion syndrome. Our ultimate goal is to identify the gene(s) that causes this disorder in order to clarify its molecular etiology and pathophysiology. This may give rise to a molecular classification of the disease as well as provide the foundation for genetic testing and new treatment approaches.

  4. Thermophysical properties of dispersed metal materials

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hyun; Kim, Jong Chul [KRISS, Taejeon (Korea)

    2002-04-01

    Thermal conductivities of the preliminarily fabricated U-Mo dispersion fuel meats have been measured to estimate the center temperature of the irradiation fuels. Thermal conductivities at temperatures ranging from room temperature to 500 .deg. C were calculated by measuring diffusivities, specific heat capacities and densities of dispersion fuel meats. The molybdenum content of fuel meats was varied to be 6wt%, 8wt%, and 10wt% and the volume fraction of U-Mo fuel powders were changed to be 10 vol%, 30vol%, 40 vol%, and 50 vol%. 13 refs., 39 figs., 13 tabs. (Author)

  5. Dispersion and transport of atmospheric pollutants

    International Nuclear Information System (INIS)

    Cieslik, S.

    1991-01-01

    This paper presents the physical mechanisms that govern the dispersion and transport of air pollutant; the influence of the state of the 'carrying fluid', i.e. the role of meteorology; and finally, outlines the different techniques of assessing the process. Aspects of physical mechanisms and meteorology covered include: fate of an air pollutant; turbulence and dispersion; transport; wind speed and direction; atmospheric stability; and the role of atmospheric water. Assessment techniques covered are: concentrations measurements; modelling meteorological observations; and tracer releases. It is concluded that the only way to reduce air pollution is to pollute less. 10 refs., 12 figs., 2 tabs

  6. Phonon dispersion curves for CsCN

    International Nuclear Information System (INIS)

    Gaur, N.K.; Singh, Preeti; Rini, E.G.; Galgale, Jyostna; Singh, R.K.

    2004-01-01

    The motivation for the present work was gained from the recent publication on phonon dispersion curves (PDCs) of CsCN from the neutron scattering technique. We have applied the extended three-body force shell model (ETSM) by incorporating the effect of coupling between the translation modes and the orientation of cyanide molecules for the description of phonon dispersion curves of CsCN between the temperatures 195 and 295 K. Our results on PDCs in symmetric direction are in good agreement with the experimental data measured with inelastic neutron scattering technique. (author)

  7. Relativistic energy loss in a dispersive medium

    DEFF Research Database (Denmark)

    Houlrik, Jens Madsen

    2002-01-01

    The electron energy loss in a dispersive medium is obtained using macroscopic electrodynamics taking advantage of a static frame of reference. Relativistic corrections are described in terms of a dispersive Lorentz factor obtained by replacing the vacuum velocity c by the characteristic phase...... velocity c/n, where n is the complex index of refraction. The angle-resolved energy-loss spectrum of a Drude conductor is analyzed in detail and it is shown that the low-energy peak due to Ohmic losses is enhanced compared to the classical approximation....

  8. Improvements in or relating to dispersions

    International Nuclear Information System (INIS)

    Woodhead, J.L.

    1981-01-01

    A process is described for the preparation of an aqueous dispersion of ceria which comprises forming a slurry of cerium IV hydroxide with water and an acid, the acid being capable of causing deaggregation of aggregated crystallites in the cerium IV hydroxide, heating the slurry for such a time and at such a temperature that the pH reaches a steady value, the quantity of acid in the slurry being such that the steady value of pH is below 5.4, thereby to produce a conditioned slurry, and admixing water with the conditioned slurry to produce an aqueous dispersion of ceria. (author)

  9. Dispersion - does it degrade a pulse envelope

    International Nuclear Information System (INIS)

    Deighton, M.O.

    1985-01-01

    In hostile environments, transmitting information as ultrasonic Lamb wave pulses has advantages, since the stainless steel strip serving as a waveguide is very durable. Besides attenuation, velocity dispersion (inherent in Lamb waves) can be important even in fairly short guides. Theory shows that unlimited propagation of a pulsed r.f. envelope is possible, even with dispersion present. The constant group velocity needed would favour asub(o)-mode pulses over other modes, provided ordinary attenuation is small. An approximate formula indicates the useful range of a pulse, when group velocity does vary. (author)

  10. Wage Dispersion and Decentralization of Wage Bargaining

    DEFF Research Database (Denmark)

    Dahl, Christian M.; Le Maire, Christian Daniel; Munch, Jakob Roland

    in the individual worker's wage-setting system that facilitates identification of the effects of decentralization. Consistent with predictions we find that wages are more dispersed under firm-level bargaining compared to more centralized wage-setting systems. However, the differences across wage-setting systems......This paper studies how decentralization of wage bargaining from sector to firm level influences wage levels and wage dispersion. We use a detailed panel data set covering a period of decentralization in the Danish labor market. The decentralization process provides exogenous variation...

  11. Saturable absorption in detonation nanodiamond dispersions

    Science.gov (United States)

    Vanyukov, Viatcheslav; Mikheev, Gennady; Mogileva, Tatyana; Puzyr, Alexey; Bondar, Vladimir; Lyashenko, Dmitry; Chuvilin, Andrey

    2017-07-01

    We report on a saturable absorption in aqueous dispersions of nanodiamonds with femtosecond laser pulse excitation at a wavelength of 795 nm. The open aperture Z-scan experiments reveal that in a wide range of nanodiamond particle sizes and concentrations, a light-induced increase of transmittance occurs. The transmittance increase originates from the saturation of light absorption and is associated with a light absorption at 1.5 eV by graphite and dimer chains (Pandey dimer chains). The obtained key nonlinear parameters of nanodiamond dispersions are compared with those of graphene and carbon nanotubes, which are widely used for the mode-locking.

  12. Effects of Earthworms on the Dispersal of Steinernema spp.

    OpenAIRE

    Shapiro, D. I.; Tylka, G. L.; Berry, E. C.; Lewis, L. C.

    1995-01-01

    Previous studies indicated that dispersal of S. carpocapsae may be enhanced in soil with earthworms. The objective of this research was to determine and compare the effects of earthworms on dispersal of other Steinernema spp. Vertical dispersal of Steinernema carpocapsae, S. feltiae, and S. glaseri was tested in soil columns in the presence and absence of earthworms (Lumbricus terrestris). Dispersal was evaluated by a bioassay and by direct extraction of nematodes from soil. Upward dispersal ...

  13. Spectral phase shift and residual angular dispersion of an accousto-optic programme dispersive filter

    International Nuclear Information System (INIS)

    Boerzsoenyi, A.; Meroe, M.

    2010-01-01

    Complete text of publication follows. There is an increasing demand for active and precise dispersion control of ultrashort laser pulses. In chirped pulse amplification (CPA) laser systems, the dispersion of the optical elements of the laser has to be compensated at least to the fourth order to obtain high temporal contrast compressed pulses. Nowadays the most convenient device for active and programmable control of spectral phase and amplitude of broadband laser pulses is the acousto-optic programmable dispersive filter (AOPDF), claimed to be able to adjust the spectral phase up to the fourth order. Although it has been widely used, surprisingly enough there has been only a single, low resolution measurement reported on the accuracy of the induced spectral phase shift of the device. In our paper we report on the first systematic experiment aiming at the precise characterization of an AOPDF device. In the experiment the spectral phase shift of the AOPDF device was measured by spectrally and spatially resolved interferometry, which is especially powerful tool to determine small dispersion values with high accuracy. Besides the spectral phase dispersion, we measured both the propagation direction angular dispersion (PDAD) and the phase front angular dispersion (PhFAD). Although the two quantities are equal for plane waves, there may be noticeable difference for Gaussian pulses. PDAD was determined simply by focusing the beam on the slit of an imaging spectrograph, while PhFAD was measured by the use of an inverted Mach-Zehnder interferometer and an imaging spectrograph. In the measurements, the spectral phase shift and both types of angular dispersion have been recorded upon the systematic change of all the accessible functions of the acousto-optic programmable dispersive filter. The measured values of group delay dispersion (GDD) and third order dispersion (TOD) have been found to agree with the preset values within the error of the measurement (1 fs 2 and 10 fs 3

  14. Cancel and rethink in the Wason selection task: further evidence for the heuristic-analytic dual process theory.

    Science.gov (United States)

    Wada, Kazushige; Nittono, Hiroshi

    2004-06-01

    The reasoning process in the Wason selection task was examined by measuring card inspection times in the letter-number and drinking-age problems. 24 students were asked to solve the problems presented on a computer screen. Only the card touched with a mouse pointer was visible, and the total exposure time of each card was measured. Participants were allowed to cancel their previous selections at any time. Although rethinking was encouraged, the cards once selected were rarely cancelled (10% of the total selections). Moreover, most of the cancelled cards were reselected (89% of the total cancellations). Consistent with previous findings, inspection times were longer for selected cards than for nonselected cards. These results suggest that card selections are determined largely by initial heuristic processes and rarely reversed by subsequent analytic processes. The present study gives further support for the heuristic-analytic dual process theory.

  15. Rethinking Assessments: Creating a New Tool Using the Zone Of Proximal Development within a Cultural-Historical Framework

    Directory of Open Access Journals (Sweden)

    Minson V.,

    2016-12-01

    Full Text Available This paper presents a picture of the current theoretical positions and methods used to assess children’s development. A maturational understanding of development is seen to be predominately used to inform the assessment tools which track how children develop across the 0—5 age group. This paper proposes that with the movement towards a cultural-historical understanding of development, a tool following from this standpoint should be developed. It is envisaged that a new assessment tool will be developed from this analysis. A theoretical rationale is given to support why the Zone of Proximal Development can be used to identify the indicators of children’s actual and potential levels of development, moving away from age/level based testing. Developing an assessment tool aligned to the principles of the ZPD can offer alternative method to assess children’s development in a theoretically robust way, providing empirical evidence to rethink the methodologies of child development assessments.

  16. Rethinking the Response to Emerging Microbes: Vaccines and Therapeutics in the Ebola Era--a Conference at Harvard Medical School.

    Science.gov (United States)

    Knipe, David M; Whelan, Sean P

    2015-08-01

    Harvard Medical School convened a meeting of biomedical and clinical experts on 5 March 2015 on the topic of "Rethinking the Response to Emerging Microbes: Vaccines and Therapeutics in the Ebola Era," with the goals of discussing the lessons from the recent Ebola outbreak and using those lessons as a case study to aid preparations for future emerging infections. The speakers and audience discussed the special challenges in combatting an infectious agent that causes sporadic outbreaks in resource-poor countries. The meeting led to a call for improved basic medical care for all and continued support of basic discovery research to provide the foundation for preparedness for future outbreaks in addition to the targeted emergency response to outbreaks and targeted research programs against Ebola virus and other specific emerging pathogens. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. Dispersant effectiveness: Studies into the causes of effectiveness variations

    International Nuclear Information System (INIS)

    Fingas, M.F.; Kyle, D.; Tennyson, E.

    1995-01-01

    Effectiveness, a key issue of using dispersants, is affected by many interrelated factors. The principal factors involved are the oil composition, dispersant formulation, sea surface turbulence and dispersant quantity. Oil composition is a very strong determinant. Current dispersant formulation effectiveness correlates strongly with the amount of saturate component in the oil. The other components of the oil, the asphaltenes, resins or polars and aromatic fractions show a negative correlation with the dispersant effectiveness. Viscosity is also a predictor of dispersant effectiveness and may have an effect because it is in turn determined by oil composition. Dispersant composition is significant and interacts with oil composition. Dispersants show high effectiveness at HLB values near 10. Sea turbulence strongly affects dispersant effectiveness.Effectiveness rises with increasing turbulence to a maximum value. Effectiveness for current commercial dispersants is gaussian around a peak salinity value. Peak effectiveness is achieved at very high dispersant quantities--at a ratio of 1:5, dispersant-to-oil volume. Dispersant effectiveness for those oils tested and under the conditions measured, is approximately logarithmic with dispersant quantity and will reach about 50% of its peak value at a dispersant to oil ratio of about 1:20 and near zero at a ratio of about 1:50

  18. Analytical simulation of two dimensional advection dispersion ...

    African Journals Online (AJOL)

    The study was designed to investigate the analytical simulation of two dimensional advection dispersion equation of contaminant transport. The steady state flow condition of the contaminant transport where inorganic contaminants in aqueous waste solutions are disposed of at the land surface where it would migrate ...

  19. Advection models of longitudinal dispersion in rivers

    NARCIS (Netherlands)

    Kranenburg, C.

    1996-01-01

    A derivation is presented of a general cross-section averaged model of longitudinal dispersion, which is based on the notion of the advection of tracer particles. Particle displacement length and particle travel time are conceived as stochastic variables, and a joint probability density function is

  20. Analytical Simulation of Two Dimensional Advection Dispersion ...

    African Journals Online (AJOL)

    ADOWIE PERE

    ABSTRACT: The study was designed to investigate the analytical simulation of two dimensional advection dispersion equation of contaminant transport. The steady state flow condition of the contaminant transport where inorganic contaminants in aqueous waste solutions are disposed of at the land surface where it would ...

  1. Dispersion of Chernobyl radioactive plume over Europe

    International Nuclear Information System (INIS)

    Albergel, A.

    1988-01-01

    A long-range pollutant transport and removal model, is used to analyse the Chernobyl radioactive plume dispersion over the Europe Continent. Model predictions are compared to field measurements of Cs-137 activity in the air from April 26th, to May 5th 1986 [fr

  2. Characterising refractive index dispersion in chalcogenide glasses

    DEFF Research Database (Denmark)

    Fang, Y.; Sojka, L.; Jayasuriya, D.

    2016-01-01

    Much effort has been devoted to the study of glasses that contain the chalcogen elements (sulfur, selenium and tellurium) for photonics' applications out to MIR wavelengths. In this paper we describe some techniques for determining the refractive index dispersion characteristics of these glasses...

  3. Dispersions in Semi-Classical Dynamics

    International Nuclear Information System (INIS)

    Zielinska-Pfabe, M.; Gregoire, C.

    1987-01-01

    Dispersions around mean values of one-body observables are obtained by restoring classical many-body correlations in Vlasov and Landau-Vlasov dynamics. The method is applied to the calculation of fluctuations in mass, charge and linear momentum in heavy-ion collisions. Results are compared to those obtained by the Balian-Veneroni variational principle in semi-classical approximation

  4. Influence of waste solid on nuclide dispersal

    International Nuclear Information System (INIS)

    Seitz, M.G.; Steindler, M.J.

    1981-01-01

    The method most often considered for permanent disposal of radioactive waste is to incorporate the waste into a solid, which is then placed in a geologic formation. The solid is made of waste and nonradioactive additives, with the formulation selected to produce a durable solid that will minimize the potential for dispersal of the radionuclides. Leach rates of radionuclides incorporated in the solid waste indicate the quantity of radioactivity available for dispersal at any time; but leach rates of stable constituents can be just as important to radionuclide dispersal by groundwater. The constituents of the solid will perturb the chemical character of the groundwater and, thereby, profoundly affect the interaction of radionuclides with the geologic medium. An explicit example of how the solid waste can affect radionuclide dispersal is illustrated by the results of experiments that measure cesium adsorption in the presence of rubidium. The experiments were performed with granulated oolitic limestone that absorbed cesium from groundwater solutions to which various concentrations of stable rubidium chloride had been added. The results are expressed as partition coefficients. Large coefficients indicate strong adsorption by the rock and, hence, slow migration. The partition coefficient for cesium decreases as the rubidium concentration in solution is increased. Because the coeficient for cesium depends on the amount of rubidium in solution, it will depend on the leach rate of rubidium from the solid. Rubidium has no radionuclides of concern for long-term isolation of nuclear waste, so its leach rate from a waste solid is rarely ever reported

  5. Fractional vector calculus for fractional advection dispersion

    Science.gov (United States)

    Meerschaert, Mark M.; Mortensen, Jeff; Wheatcraft, Stephen W.

    2006-07-01

    We develop the basic tools of fractional vector calculus including a fractional derivative version of the gradient, divergence, and curl, and a fractional divergence theorem and Stokes theorem. These basic tools are then applied to provide a physical explanation for the fractional advection-dispersion equation for flow in heterogeneous porous media.

  6. Laterally and longitudinally dispersive recoil mass separators

    International Nuclear Information System (INIS)

    Wollnik, H.

    1987-01-01

    Principles of laterally dispersive and time-of-flight mass separators are outlined. Special emphasis is given to separators for very energetic recoils for which electrostatic fields would be technologically impossible. The principle of energy isochronous time-of-flight mass separators is shown to be applicable to storage rings. (orig.)

  7. Problems with Discontinuous Diffusion/Dispersion Coefficients

    Directory of Open Access Journals (Sweden)

    Stefano Ferraris

    2012-01-01

    accurate on smooth solutions and based on a special numerical treatment of the diffusion/dispersion coefficients that makes its application possible also when such coefficients are discontinuous. Numerical experiments confirm the convergence of the numerical approximation and show a good behavior on a set of benchmark problems in two space dimensions.

  8. Fused deposition modelling of sodium caseinate dispersions

    NARCIS (Netherlands)

    Schutyser, M.A.I.; Houlder, S.; Wit, de Martin; Buijsse, C.A.P.; Alting, A.C.

    2018-01-01

    Only recently, researchers have started experimenting with 3D printing of foods. The aim of this study was to investigate 3D printed objects from sodium caseinate dispersions, exhibiting reversible gelation behaviour. Gelation and dispensing behaviour were explored and structures of different

  9. New Information Dispersal Techniques for Trustworthy Computing

    Science.gov (United States)

    Parakh, Abhishek

    2011-01-01

    Information dispersal algorithms (IDA) are used for distributed data storage because they simultaneously provide security, reliability and space efficiency, constituting a trustworthy computing framework for many critical applications, such as cloud computing, in the information society. In the most general sense, this is achieved by dividing data…

  10. Accelerated Physical Stability Testing of Amorphous Dispersions.

    Science.gov (United States)

    Mehta, Mehak; Suryanarayanan, Raj

    2016-08-01

    The goal was to develop an accelerated physical stability testing method of amorphous dispersions. Water sorption is known to cause plasticization and may accelerate drug crystallization. In an earlier investigation, it was observed that both the increase in mobility and decrease in stability in amorphous dispersions was explained by the "plasticization" effect of water (Mehta et al. Mol. Pharmaceutics 2016, 13 (4), 1339-1346). In this work, the influence of water concentration (up to 1.8% w/w) on the correlation between mobility and crystallization in felodipine dispersions was investigated. With an increase in water content, the α-relaxation time as well as the time for 1% w/w felodipine crystallization decreased. The relaxation times of the systems, obtained with different water concentration, overlapped when the temperature was scaled (Tg/T). The temperature dependencies of the α-relaxation time as well as the crystallization time were unaffected by the water concentration. Thus, the value of the coupling coefficient, up to a water concentration of 1.8% w/w, was approximately constant. Based on these findings, the use of "water sorption" is proposed to build predictive models for crystallization in slow crystallizing dispersions.

  11. Mars Exploration Rovers Landing Dispersion Analysis

    Science.gov (United States)

    Knocke, Philip C.; Wawrzyniak, Geoffrey G.; Kennedy, Brian M.; Desai, Prasun N.; Parker, TImothy J.; Golombek, Matthew P.; Duxbury, Thomas C.; Kass, David M.

    2004-01-01

    Landing dispersion estimates for the Mars Exploration Rover missions were key elements in the site targeting process and in the evaluation of landing risk. This paper addresses the process and results of the landing dispersion analyses performed for both Spirit and Opportunity. The several contributors to landing dispersions (navigation and atmospheric uncertainties, spacecraft modeling, winds, and margins) are discussed, as are the analysis tools used. JPL's MarsLS program, a MATLAB-based landing dispersion visualization and statistical analysis tool, was used to calculate the probability of landing within hazardous areas. By convolving this with the probability of landing within flight system limits (in-spec landing) for each hazard area, a single overall measure of landing risk was calculated for each landing ellipse. In-spec probability contours were also generated, allowing a more synoptic view of site risks, illustrating the sensitivity to changes in landing location, and quantifying the possible consequences of anomalies such as incomplete maneuvers. Data and products required to support these analyses are described, including the landing footprints calculated by NASA Langley's POST program and JPL's AEPL program, cartographically registered base maps and hazard maps, and flight system estimates of in-spec landing probabilities for each hazard terrain type. Various factors encountered during operations, including evolving navigation estimates and changing atmospheric models, are discussed and final landing points are compared with approach estimates.

  12. Theoretical Magnon Dispersion Curves for Gd

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker; Harmon, B. N.; Freeman, A. J.

    1975-01-01

    The magnon dispersion curve of Gd metal has been determined from first principles by use of augmented-plane-wave energy bands and wave functions. The exchange matrix elements I(k⃗, k⃗′) between the 4f electrons and the conduction electrons from the first six energy bands were calculated under...

  13. Dispersion analysis of spaced antenna scintillation measurement

    Directory of Open Access Journals (Sweden)

    M. Grzesiak

    2009-07-01

    Full Text Available We present a dispersion analysis of the phase of GPS signals received at high latitude. Basic theoretical aspects for spectral analysis of two-point measurement are given. To account for nonstationarity and statistical robustness a power distribution of the windowed Fourier transform cross-spectra as a function of frequency and phase is analysed using the Radon transform.

  14. FEATURES OF RESTORATION OF DISPERSE POROUS MATERIALS

    Directory of Open Access Journals (Sweden)

    S. L. Rovin

    2016-01-01

    Full Text Available The article presents the results of research recycling of dispersed materials in rotary furnaces. Has been received new data on the of heat and mass transfer processes and carry out intensive and continuous process of solid- liquid-phase reduction of oxides in a single unit.

  15. Polymer Inclusion Membranes with Strip Dispersion

    Directory of Open Access Journals (Sweden)

    Yueh-Hsien Li

    2017-06-01

    Full Text Available The present work investigated the permeation of indium ions through a polymer inclusion membrane (PIM, prepared with cellulose triacetate (CTA as the base polymer, tris(2-butoxyethyl phosphate (TBEP as the plasticizer and di-(2-ethylhexylphosphoric acid (D2EHPA as the extractant. With 5 M HCl aqueous solution as the strip solution, we observed an initial indium permeability of 2.4 × 10−4 m/min. However, the permeability decreases with time, dropping to about 3.4 × 10−5 m/min after 200 min of operation. Evidence was obtained showing that hydrolysis of CTA occurred, causing a dramatic decrease in the feed pH (protons transported from strip to feed solutions and a loss of extractant and plasticizer from the membrane, and then leading to the loss of indium permeability. To alleviate the problem of hydrolysis, we proposed an operation scheme called polymer inclusion membranes with strip dispersion: dispersing the strip solution in extractant-containing oil and then bringing the dispersion to contact with the polymer membrane. Since the strong acid was dispersed in oil, the membrane did not directly contact the strong acid at all times, and membrane hydrolysis was thus alleviated and the loss of indium permeability was effectively prevented. With the proposed scheme, a stable indium permeability of 2.5 × 10−4 m/min was obtained during the whole time period of the permeation experiment.

  16. Overseas seed dispersal by migratory birds

    NARCIS (Netherlands)

    Viana, D.S.; Gangoso, L.; Bouten, W.; Figuerola, J.

    2016-01-01

    Long-distance dispersal (LDD) promotes the colonization of isolated and remote habitats, and thus it has been proposed as a mechanism for explaining the distributions of many species. Birds are key LDD vectors for many sessile organisms such as plants, yet LDD beyond local and regional scales has

  17. Dispersion of breakdown voltage of liquid helium

    International Nuclear Information System (INIS)

    Ishii, Itaru; Noguchi, Takuya

    1978-01-01

    As for the electrical insulation characteristics of liquid helium, the discrepancy among the measured values by each person is very large even in the fundamental DC breakdown voltage in uniform electric field. The dispersion of experimental values obtained in the experiments by the same person is also large. Hereafter, the difference among the mean values obtained by each experimenter will be referred to as ''deviation of mean values'', and the dispersion of measured values around the mean value obtained by the same person as ''deviation around the man value''. The authors have mainly investigated on the latter experimentally. The cryostat was made of stainless steel, and the innermost helium chamber was of 500 mm I.D. and approximately 1200 mm deep. The high voltage electrode was of brass sphere of 25 mm diameter, and the low voltage electrode was of brass plate. The experiment was conducted for liquid helium boiling at 4.2 K and 1 atm, and the breakdown voltage and time lag were measured by applying the approximately square wave impulses of fast rise and long tail, ramp and DC voltages. The cause of the deviation of mean values may be the presence of impurity particles or the effect of electrode shape. As for the deviation around the mean value, the dispersion is large, and its standard deviation may amount to 10 to 20% of the man value. The dispersion is not due to the statistical time lag, but is due to parameters that vary with breakdown. (Wakatsuki, Y.)

  18. Computing modal dispersion characteristics of radially Asymmetric ...

    African Journals Online (AJOL)

    We developed a matrix theory that applies to with non-circular/circular but concentric layers fibers. And we compute the dispersion characteristics of radially unconventional fiber, known as Asymmetric Bragg fiber. An attempt has been made to determine how the modal characteristics change as circular Bragg fiber is ...

  19. Chemical countermeasures: Dispersants overview of dispersant use (including application) and research issues

    International Nuclear Information System (INIS)

    Butler, J.N.

    1992-01-01

    I will attempt in twenty minutes to summarize the state of research on oil spill dispersants as I perceive it. The expertise I bring to this task includes 20 years of experience with the fate and effects of petroleum in the marine environment, including participation in the 1973 and 1981 NRC studies and three years as chairman of the NRC committee on oil spill dispersants. I More recently I served on a committee of the International Maritime Organization which reviewed the open-quotes Impact of oil and related chemicals and wastes on the marine environment.close quotes That report will be published this year. However, my statements in this paper are not made as a representative of either NRC or IMO. They are my own interpretation of scientific literature cited in the above reviews. Dispersants are chemical formulations, which include surface active agents, designed to decrease the interfacial tension between oil and water. Because the first attempts to disperse oil on a large scale, at the Torrey Canyon spill of 1967, used highly toxic degreasing agents, dispersants have an undeserved reputation for toxicity. In fact, for twenty years dispersant formulations have been developed with an emphasis on reducing their toxicity to marine life. The dispersal of oil in water has been documented in the laboratory by dozens of papers (see references in NRC 1989, pp 70-79), and in the field by dozens of studies (NRC 1989, pp 165- 193). The toxicity of commercial dispersant formulations (NRC 1989, pp 81-123) and dispersed oil (NRC 1989, pp 123-147) has been tested on a wide variety of marine organisms ranging from algae to salmonid fishes. The NRC review has been updated by the IMO/GESAMP (1992) study, but the conclusions remain unchanged

  20. Reliability benefits of dispersed wind resource development

    International Nuclear Information System (INIS)

    Milligan, M.; Artig, R.

    1998-05-01

    Generating capacity that is available during the utility peak period is worth more than off-peak capacity. Wind power from a single location might not be available during enough of the peak period to provide sufficient value. However, if the wind power plant is developed over geographically disperse locations, the timing and availability of wind power from these multiple sources could provide a better match with the utility's peak load than a single site. There are other issues that arise when considering disperse wind plant development. Singular development can result in economies of scale and might reduce the costs of obtaining multiple permits and multiple interconnections. However, disperse development can result in cost efficiencies if interconnection can be accomplished at lower voltages or at locations closer to load centers. Several wind plants are in various stages of planning or development in the US. Although some of these are small-scale demonstration projects, significant wind capacity has been developed in Minnesota, with additional developments planned in Wyoming, Iowa and Texas. As these and other projects are planned and developed, there is a need to perform analysis of the value of geographically disperse sites on the reliability of the overall wind plant.This paper uses a production-cost/reliability model to analyze the reliability of several wind sites in the state of Minnesota. The analysis finds that the use of a model with traditional reliability measures does not produce consistent, robust results. An approach based on fuzzy set theory is applied in this paper, with improved results. Using such a model, the authors find that system reliability can be optimized with a mix of disperse wind sites

  1. The concave iris in pigment dispersion syndrome.

    Science.gov (United States)

    Liu, Lance; Ong, Ee Lin; Crowston, Jonathan

    2011-01-01

    To visualize the changes of the iris contour in patients with pigment dispersion syndrome after blinking, accommodation, and pharmacologic miosis using anterior segment optical coherence tomography. Observational case series. A total of 33 eyes of 20 patients with pigment dispersion syndrome. Each eye was imaged along the horizontal 0- to 180-degree meridian using the Visante Anterior Segment Imaging System (Carl Zeiss Meditec, Dublin, CA). Scans were performed at baseline and after focusing on an internal fixation target for 5 minutes, forced blinking, accommodation, and pharmacologic miosis with pilocarpine 2%. Quantitative analysis of the changes in the iris configuration. After 5 minutes of continual fixation, the iris became planar with the mean ± standard deviation curvature decreasing from 214 ± 74 μm to 67 ± 76 μm (P pigment dispersion syndrome after forced blinking, but the iris concavity recovered to 227 ± 113 μm (P = 0.34) and 238 ± 119 μm (P = 0.19) with the -3.0 and -6.0 diopter lenses, respectively. Pilocarpine-induced miosis caused the iris to assume a planar configuration in all subjects. This study shows that the iris in pigment dispersion syndrome assumes a planar configuration when fixating and that the concavity of the iris surface is not restored by blinking. Accommodation restored the iris concavity, suggesting that the posterior curvature of the iris in pigment dispersion syndrome is induced and probably maintained, at least in part, by accommodation. Copyright © 2011 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  2. The trajectory of dispersal research in conservation biology. Systematic review.

    Directory of Open Access Journals (Sweden)

    Don A Driscoll

    Full Text Available Dispersal knowledge is essential for conservation management, and demand is growing. But are we accumulating dispersal knowledge at a pace that can meet the demand? To answer this question we tested for changes in dispersal data collection and use over time. Our systematic review of 655 conservation-related publications compared five topics: climate change, habitat restoration, population viability analysis, land planning (systematic conservation planning and invasive species. We analysed temporal changes in the: (i questions asked by dispersal-related research; (ii methods used to study dispersal; (iii the quality of dispersal data; (iv extent that dispersal knowledge is lacking, and; (v likely consequences of limited dispersal knowledge. Research questions have changed little over time; the same problems examined in the 1990s are still being addressed. The most common methods used to study dispersal were occupancy data, expert opinion and modelling, which often provided indirect, low quality information about dispersal. Although use of genetics for estimating dispersal has increased, new ecological and genetic methods for measuring dispersal are not yet widely adopted. Almost half of the papers identified knowledge gaps related to dispersal. Limited dispersal knowledge often made it impossible to discover ecological processes or compromised conservation outcomes. The quality of dispersal data used in climate change research has increased since the 1990s. In comparison, restoration ecology inadequately addresses large-scale process, whilst the gap between knowledge accumulation and growth in applications may be increasing in land planning. To overcome apparent stagnation in collection and use of dispersal knowledge, researchers need to: (i improve the quality of available data using new approaches; (ii understand the complementarities of different methods and; (iii define the value of different kinds of dispersal information for supporting

  3. The trajectory of dispersal research in conservation biology. Systematic review.

    Science.gov (United States)

    Driscoll, Don A; Banks, Sam C; Barton, Philip S; Ikin, Karen; Lentini, Pia; Lindenmayer, David B; Smith, Annabel L; Berry, Laurence E; Burns, Emma L; Edworthy, Amanda; Evans, Maldwyn J; Gibson, Rebecca; Heinsohn, Rob; Howland, Brett; Kay, Geoff; Munro, Nicola; Scheele, Ben C; Stirnemann, Ingrid; Stojanovic, Dejan; Sweaney, Nici; Villaseñor, Nélida R; Westgate, Martin J

    2014-01-01

    Dispersal knowledge is essential for conservation management, and demand is growing. But are we accumulating dispersal knowledge at a pace that can meet the demand? To answer this question we tested for changes in dispersal data collection and use over time. Our systematic review of 655 conservation-related publications compared five topics: climate change, habitat restoration, population viability analysis, land planning (systematic conservation planning) and invasive species. We analysed temporal changes in the: (i) questions asked by dispersal-related research; (ii) methods used to study dispersal; (iii) the quality of dispersal data; (iv) extent that dispersal knowledge is lacking, and; (v) likely consequences of limited dispersal knowledge. Research questions have changed little over time; the same problems examined in the 1990s are still being addressed. The most common methods used to study dispersal were occupancy data, expert opinion and modelling, which often provided indirect, low quality information about dispersal. Although use of genetics for estimating dispersal has increased, new ecological and genetic methods for measuring dispersal are not yet widely adopted. Almost half of the papers identified knowledge gaps related to dispersal. Limited dispersal knowledge often made it impossible to discover ecological processes or compromised conservation outcomes. The quality of dispersal data used in climate change research has increased since the 1990s. In comparison, restoration ecology inadequately addresses large-scale process, whilst the gap between knowledge accumulation and growth in applications may be increasing in land planning. To overcome apparent stagnation in collection and use of dispersal knowledge, researchers need to: (i) improve the quality of available data using new approaches; (ii) understand the complementarities of different methods and; (iii) define the value of different kinds of dispersal information for supporting management

  4. Design of self-dispersible charged-polymer building blocks for waterborne polyurethane dispersions

    NARCIS (Netherlands)

    Jiménez-Pardo, I.; Sun, P.; van Benthem, R.A.T.M.; Esteves, A.C.C.

    2018-01-01

    Waterborne polyurethane dispersions (PUDs) currently have a wide spectrum of applications as coating resins for biomedical products, food packaging, cosmetics and traditional coatings. At present, PUDs are commonly prepared by the “prepolymer extension” method in which isocyanate terminated

  5. Aqueous solubility, dispersibility and toxicity of biodiesels

    International Nuclear Information System (INIS)

    Hollebone, B.P.; Fieldhouse, B.; Lumley, T.C.; Landriault, M.; Doe, K.; Jackman, P.

    2007-01-01

    The renewed interest in the use of biological fuels can be attributed to that fact that feedstocks for fatty-acid ester biodiesels are renewable and can be reclaimed from waste. Although there are significant benefits to using biodiesels, their increased use leaves potential for accidental release to the environment. Therefore, their environmental behaviours and impacts must be evaluated along with the risk associated with their use. Biodiesel fuels may be made from soy oil, canola oil, reclaimed restaurant grease, fish oil and animal fat. The toxicological fate of biofuel depends on the variability of its chemical composition. This study provided an initial assessment of the aqueous fate and effects of biodiesel from a broad range of commonly available feedstocks and their blends with petroleum diesels. The study focused primarily on the fate and impact of these fuels in fresh-water. The use of chemical dispersion as a countermeasure for saltwater was also investigated. The exposure of aquatic ecosystems to biodiesels and petroleum diesel occurs via the transfer of material from the non-aqueous phase liquid (NAPL) into the aqueous phase, as both soluble and dispersed components. The aqueous solubilities of the fuels were determined from the equilibrium water-accommodated fraction concentrations. The acute toxicities of many biodiesels were reported for 3 test species used by Environment Canada for toxicological evaluation, namely rainbow trout, the water flea and a luminescent bacterium. This study also evaluated the natural potential for dispersion of the fuels in the water column in both low and high-energy wave conditions. Chemical dispersion as a potential countermeasure for biodiesel spills was also evaluated using solubility testing, acute toxicity testing, and dispersibility testing. It was shown that biodiesels have much different fates and impacts from petroleum diesels. The compounds partitioning into the water column are also very different for each

  6. Modifying Silicates for Better Dispersion in Nanocomposites

    Science.gov (United States)

    Campbell, Sandi

    2005-01-01

    An improved chemical modification has been developed to enhance the dispersion of layered silicate particles in the formulation of a polymer/silicate nanocomposite material. The modification involves, among other things, the co-exchange of an alkyl ammonium ion and a monoprotonated diamine with interlayer cations of the silicate. The net overall effects of the improved chemical modification are to improve processability of the nanocomposite and maximize the benefits of dispersing the silicate particles into the polymer. Some background discussion is necessary to give meaning to a description of this development. Polymer/silicate nanocomposites are also denoted polymer/clay composites because the silicate particles in them are typically derived from clay particles. Particles of clay comprise layers of silicate platelets separated by gaps called "galleries." The platelet thickness is 1 nm. The length varies from 30 nm to 1 m, depending on the silicate. In order to fully realize the benefits of polymer/silicate nanocomposites, it is necessary to ensure that the platelets become dispersed in the polymer matrices. Proper dispersion can impart physical and chemical properties that make nanocomposites attractive for a variety of applications. In order to achieve nanometer-level dispersion of a layered silicate into a polymer matrix, it is typically necessary to modify the interlayer silicate surfaces by attaching organic functional groups. This modification can be achieved easily by ion exchange between the interlayer metal cations found naturally in the silicate and protonated organic cations - typically protonated amines. Long-chain alkyl ammonium ions are commonly chosen as the ion-exchange materials because they effectively lower the surface energies of the silicates and ease the incorporation of organic monomers or polymers into the silicate galleries. This completes the background discussion. In the present improved modification of the interlayer silicate surfaces

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

    Science.gov (United States)

    Kayumova, Shakhnoza; Tippins, Deborah

    2016-09-01

    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)38:33.0.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 experiences reforms

  8. Wage Dispersion and Decentralization of Wage Bargaining

    DEFF Research Database (Denmark)

    Dahl, Christian Møller; le Maire, Christian Daniel; Munch, Jakob R.

    2013-01-01

    This article studies how decentralization of wage bargaining from sector to firm level influences wage levels and wage dispersion. We use detailed panel data covering a period of decentralization in the Danish labor market. The decentralization process provides variation in the individual worker......'s wage-setting system that facilitates identification of the effects of decentralization. We find a wage premium associated with firm-level bargaining relative to sector-level bargaining and that the return to skills is higher under the more decentralized wage-setting systems. Using quantile regression......, we also find that wages are more dispersed under firm-level bargaining compared to more centralized wage-setting systems....

  9. Anomalous acoustic dispersion in architected microlattice metamaterials

    Science.gov (United States)

    KröDel, Sebastian; Palermo, Antonio; Daraio, Chiara

    The ability to control dispersion in acoustic metamaterials is crucial to realize acoustic filtering and rectification devices as well as perfect imaging using negative refractive index materials. Architected microlattice metamaterials immersed in fluid constitute a versatile platform for achieving such control. We investigate architected microlattice materials able to exploit locally resonant modes of their fundamental building blocks that couple with propagating acoustic waves. Using analytical, numerical and experimental methods we find that such lattice materials show a hybrid dispersion behavior governed by Biot's theory for long wavelengths and multiple scattering theory when wave frequency is close to the resonances of the building block. We identify the relevant geometric parameters to alter and control the group and phase velocities in this class of acoustic metamaterials. Furthermore, we fabricate small-scale acoustic metamaterial samples using high precision SLA additive manufacturing and test the resulting materials experimentally using a customized ultrasonic setup. This work paves the way for new acoustic devices based on microlattice metamaterials.

  10. Radiological Dispersion Devices: are we prepared?

    Energy Technology Data Exchange (ETDEWEB)

    Sohier, Alain [Decision Strategy Research Department (Radiation Protection Division), Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, B-2400 Mol (Belgium)]. E-mail: asohier@sckcen.be; Hardeman, Frank [Decision Strategy Research Department (Radiation Protection Division), Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, B-2400 Mol (Belgium)

    2006-07-01

    Already before the events of September 11th 2001 concern was raised about the spread of orphan sources and their potential use in Radiological Dispersion Devices by terrorist groups. Although most of the simulated scenarios foresee a rather limited direct health impact on the population, the affected region would suffer from the indirect consequences such as social disruption, cleanup requirements and economic costs. The nature of such a radiological attack would anyway be different compared to conventional radiological accidents, basically because it can happen anywhere at any time. Part of the response resides in a general preparedness scheme incorporating attacks with Radiological Dispersion Devices. Training of different potential intervention teams is essential. The response would consist of a prioritised list of actions adapted to the circumstances. As the psychosocial dimension of the crisis could be worse than the purely radiological one, an adapted communication strategy with the public aspect would be a key issue.

  11. Gold Nanospheres Dispersed Light Responsive Epoxy Vitrimers

    Directory of Open Access Journals (Sweden)

    Zhenhua Wang

    2018-01-01

    Full Text Available Vitrimers represent a new class of smart materials. They are covalently crosslinked like thermosets, yet they can be reprocessed like thermoplastics. The underlying mechanism is the rapid exchange reactions which form new bonds while breaking the old ones. So far, heating is the most widely used stimulus to activate the exchange reaction. Compared to heating, light not only is much more convenient to achieve remote and regional control, but can also offer fast healing. Gold nanospheres are excellent photothermal agents, but they are difficult to disperse into vitrimers as they easily aggregate. In this paper, we use polydopamine to prepare gold nanospheres. The resultant polydopamine-coated gold nanospheres (GNS can be well dispersed into epoxy vitrimers, endowing epoxy vitrimers with light responsivity. The composites can be reshaped permanently and temporarily with light at different intensity. Efficient surface patterning and healing are also demonstrated.

  12. A THEOREM ON CENTRAL VELOCITY DISPERSIONS

    International Nuclear Information System (INIS)

    An, Jin H.; Evans, N. Wyn

    2009-01-01

    It is shown that, if the tracer population is supported by a spherical dark halo with a core or a cusp diverging more slowly than that of a singular isothermal sphere (SIS), the logarithmic cusp slope γ of the tracers must be given exactly by γ = 2β, where β is their velocity anisotropy parameter at the center unless the same tracers are dynamically cold at the center. If the halo cusp diverges faster than that of the SIS, the velocity dispersion of the tracers must diverge at the center too. In particular, if the logarithmic halo cusp slope is larger than two, the diverging velocity dispersion also traces the behavior of the potential. The implication of our theorem on projected quantities is also discussed. We argue that our theorem should be understood as a warning against interpreting results based on simplifying assumptions such as isotropy and spherical symmetry.

  13. Round beams generated by vertical dispersion

    International Nuclear Information System (INIS)

    Bagley, P.

    1990-01-01

    Simulations suggest that in e + e - storage rings collisions of round beams (equal emittances and equal β*) can produce very large tune shifts and luminosities. We understand how to make equal β*s, but generating equal emittances is more difficult. We describe an equal emittance scheme that uses several skew quads to couple horizontal dispersion into vertical dispersion. These skew quads also produce a coupling bump. At the interaction point and at other points outside the coupling bump, the motion is not coupled, so that the 'A' normal mode corresponds to horizontal motion and the 'B' normal mode corresponds to vertical motion. We present a round beam lattice for CESR that incorporates this scheme

  14. New developments in dispersion theory. I

    International Nuclear Information System (INIS)

    Hamilton, J.; Petersen, J.L.

    1975-01-01

    The notes arose out of a series of lectures given in Copenhagen in 1973/74. The principal aim of the course was to give a reasonably comprehensive account of the considerable number of new ideas and techniques in dispersion theory which have been developed over the past few years. General background material is also given but is treated in less detail. Modern dispersion theory is seen to have two principal types of application in high energy strong interaction physics. Although not sharply seperated they can be characterized roughly as (1) use of dynamical singularities in the amplitude analysis of experimental data, and (2) dynamical interpretation of hadronic amplitudes. In the first volume the authors have concentrated on applications of the first class. A companion volume is planned in which some of the important dominantly dynamical areas of application will be described. (Auth.)

  15. Dispersion and stabilization of cochleate nanoparticles.

    Science.gov (United States)

    Bozó, Tamás; Wacha, András; Mihály, Judith; Bóta, Attila; Kellermayer, Miklós S Z

    2017-08-01

    Cochleates, calcium-stabilized membrane rolls of nanoscale diameter, promise a unique and efficient way of delivering lipid-soluble drugs, proteins or nucleic acids into biological systems because they protect the encapsulated material against enzymatic or chemical degradation. Self-aggregation, which typically arises during production and storage is a major obstacle that has so far precluded the development of an efficient cochleate-based drug-delivery system. Here we show that citric acid, added transiently in a narrow concentration range, effectively disperses cochleate aggregates, stabilizes the disperse state for long-term storage and preserves the canonical ultrastructure and topological characteristics of cochleate nanoparticles. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Atmospheric tracer experiments for regional dispersion studies

    International Nuclear Information System (INIS)

    Heffter, J.L.; Ferber, G.J.

    1980-01-01

    Tracer experiments are being conducted to verify atmospheric transport and dispersion calculations at distances from tens to hundreds of km from pollutant sources. In one study, a 2 1/2 year sampling program has been carried out at 13 sites located 30 to 140 km from a source of 85 Kr at the Savannah River Plant in South Carolina. Average weekly concentrations as well as twice-daily concentrations were obtained. Sampling data and meteorological data, including surface, tower, and rawinsonde observations are available on magnetic tape for model verification studies. Some verification results for the Air Resources Laboratories Atmospheric Transort and Dispersion Model (ARL-ATAD) are shown for averaging periods from one week to two years

  17. Corneal collagen crosslinking and pigment dispersion syndrome.

    Science.gov (United States)

    LaHood, Benjamin R; Moore, Sacha

    2017-03-01

    We describe the case of a keratoconus patient with pigment dispersion syndrome (PDS) who was treated for progressive corneal ectasia with corneal collagen crosslinking (CXL). Pigment dispersion syndrome has been shown to have associated morphologic changes of the corneal endothelium. Corneal CXL has the potential to cause toxicity to the corneal endothelium, and adjacent pigment might increase the likelihood of damage. In this case, the presence of PDS had no detrimental effect on the outcome of treatment, and no complications were observed at 12 months follow-up, indicating that it may be safe to perform corneal CXL in the setting of PDS. This is an important observation as the number of indications for corneal CXL grows. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  18. Uncertainty in dispersion forecasts using meteorological ensembles

    International Nuclear Information System (INIS)

    Chin, H N; Leach, M J

    1999-01-01

    The usefulness of dispersion forecasts depends on proper interpretation of results. Understanding the uncertainty in model predictions and the range of possible outcomes is critical for determining the optimal course of action in response to terrorist attacks. One of the objectives for the Modeling and Prediction initiative is creating tools for emergency planning for special events such as the upcoming the Olympics. Meteorological forecasts hours to days in advance are used to estimate the dispersion at the time of the event. However, there is uncertainty in any meteorological forecast, arising from both errors in the data (both initial conditions and boundary conditions) and from errors in the model. We use ensemble forecasts to estimate the uncertainty in the forecasts and the range of possible outcomes

  19. Highly dispersive transparency in coupled metamaterials

    International Nuclear Information System (INIS)

    Thuy, V T T; Park, J W; Lee, Y P; Tung, N T; Lam, V D; Rhee, J Y

    2010-01-01

    We investigate the coupling between bright and quasi-dark eigenmodes in a planar metamaterial supporting highly dispersive transparency. The specific design of such a metamaterial consists of a cut wire (CW) and a single-gap split-ring resonator (SRR). Through the numerical simulation and the equivalent-circuit analysis, we demonstrate that the response of the SRR, which is weakly excited by external electric field, plays the role of a quasi-dark eigenmode in the presence of a strongly radiative CW. Furthermore, by extending and relating our study to the trapped mode resonances and the coupling between dark and bright modes, a more comprehensive perspective for the metamaterial realization of highly dispersive transmission and slow-light applications is provided

  20. Debris Dispersion Model Using Java 3D

    Science.gov (United States)

    Thirumalainambi, Rajkumar; Bardina, Jorge

    2004-01-01

    This paper describes web based simulation of Shuttle launch operations and debris dispersion. Java 3D graphics provides geometric and visual content with suitable mathematical model and behaviors of Shuttle launch. Because the model is so heterogeneous and interrelated with various factors, 3D graphics combined with physical models provides mechanisms to understand the complexity of launch and range operations. The main focus in the modeling and simulation covers orbital dynamics and range safety. Range safety areas include destruct limit lines, telemetry and tracking and population risk near range. If there is an explosion of Shuttle during launch, debris dispersion is explained. The shuttle launch and range operations in this paper are discussed based on the operations from Kennedy Space Center, Florida, USA.

  1. Dispersion relations in three-particle systems

    International Nuclear Information System (INIS)

    Grach, I.L.; Harodetskij, I.M.; Shmatikov, M.Zh.

    1979-01-01

    Positions of all dynamical singularities of the triangular nonrelativistic diagram are calculated including the form factors. The jumps of the amplitude are written in an analitical form. The dispersion method predictions for bound states in the three-particle system are compared with the results of the Amado exactly solvable model. It is shown that the one-channel N/D method is equivalent to the pole approximation in the Amado model, and that the three-particle s channel unitarity should be taken into account calculating (in the dispersion method) the ground and excited states of the three-particle system. The relation of the three-particle unitary contribution to the Thomas theorem and Efimov effect is briefly discussed

  2. Modified dispersion relations, inflation, and scale invariance

    Science.gov (United States)

    Bianco, Stefano; Friedhoff, Victor Nicolai; Wilson-Ewing, Edward

    2018-02-01

    For a certain type of modified dispersion relations, the vacuum quantum state for very short wavelength cosmological perturbations is scale-invariant and it has been suggested that this may be the source of the scale-invariance observed in the temperature anisotropies in the cosmic microwave background. We point out that for this scenario to be possible, it is necessary to redshift these short wavelength modes to cosmological scales in such a way that the scale-invariance is not lost. This requires nontrivial background dynamics before the onset of standard radiation-dominated cosmology; we demonstrate that one possible solution is inflation with a sufficiently large Hubble rate, for this slow roll is not necessary. In addition, we also show that if the slow-roll condition is added to inflation with a large Hubble rate, then for any power law modified dispersion relation quantum vacuum fluctuations become nearly scale-invariant when they exit the Hubble radius.

  3. Radiological Dispersion Devices: are we prepared?

    International Nuclear Information System (INIS)

    Sohier, Alain; Hardeman, Frank

    2006-01-01

    Already before the events of September 11th 2001 concern was raised about the spread of orphan sources and their potential use in Radiological Dispersion Devices by terrorist groups. Although most of the simulated scenarios foresee a rather limited direct health impact on the population, the affected region would suffer from the indirect consequences such as social disruption, cleanup requirements and economic costs. The nature of such a radiological attack would anyway be different compared to conventional radiological accidents, basically because it can happen anywhere at any time. Part of the response resides in a general preparedness scheme incorporating attacks with Radiological Dispersion Devices. Training of different potential intervention teams is essential. The response would consist of a prioritised list of actions adapted to the circumstances. As the psychosocial dimension of the crisis could be worse than the purely radiological one, an adapted communication strategy with the public aspect would be a key issue

  4. Dispersed generation: impact on the electricity system

    International Nuclear Information System (INIS)

    Delfanti, M.; Merlo, M.; Silvestri, A.

    2009-01-01

    The paper deals with the impact of Dispersed Generation (D G) on the national electricity system, by proposing a practical approach for determining the current capacity of the networks to accepts this form of generation (hosting capacity). With the prospect of an increasing intake of D G, we finally draft a possible evolution of distribution networks based on the integration of energy and information networks. [it

  5. [Disperse endocrine system and APUD concept].

    Science.gov (United States)

    Mil'to, I V; Sukhodolo, I V; Gereng, E A; Shamardina, L A

    2011-01-01

    This review describes the problems of disperse endocrine system and APUD-system morphology, summarizes some debatable issues of single endocrine cell biology. The data presented refer to the history of both systems discovery, morphological methods of their study, developmental sources, their structural organization and physiological roles of their cells. The significance of single endocrine cells in the regulation of the organism functions is discussed.

  6. Titanium oxide dispersion-strengthened ferritic alloys

    International Nuclear Information System (INIS)

    Hendrix, W.; Vandermeulen, W.

    1980-04-01

    The available data on the DT02 and DT3911 ferritic dispersion strengthened alloys, developed at SCK/CEN, Mol, Belgium, are presented. Both alloys consist of Fe - 13% Cr - 1.5% Mo to which 2% TiO 2 and about 3.5% Ti are added (wt.%). Their main use is for the fabrication of fast breeder reactor cladding tubes but their application as turbine blade material is also envisaged for cases where high damping is important. (auth.)

  7. NMR dispersion measurement of dynamic nuclear polarization

    International Nuclear Information System (INIS)

    Davies, K.; Cox, S.F.J.

    1978-01-01

    The feasibility of monitoring dynamic nuclear polarization from the NMR dispersive susceptibility is examined. Two prototype instruments are tested in a polarized proton target using organic target material. The more promising employs a tunnel diode oscillator, inside the target cavity, and should provide a precise polarization measurement working at a frequency far enough from the main resonance for the disturbance of the measured polarization to be negligible. Other existing methods for measuring target polarization are briefly reviewed. (author)

  8. REVIEW ON SPRAY DRIED SOLID DISPERSION

    OpenAIRE

    Zambre Radhika Ashok, Dr. Shendge R.S, Narode Pravin Ravindra, Sonawane Swapnil Prakash

    2018-01-01

    The drug solubility is the most challenging aspect for the formulation development. The poorly soluble drug has poor dissolution and absorption of drug. The low aqueous solubility of drug is required to formulate the drug into more soluble and hence bioavailable drug product. The different technique is being used to enhance the solubility of poorly water soluble drugs. Spray dried solid dispersion of drug is one of the most widely used technology to enhance the solubility of the poorly water ...

  9. Effective spectral dispersion of refractive index modulation

    Czech Academy of Sciences Publication Activity Database

    Vojtíšek, Petr; Květoň, M.; Richter, I.

    2017-01-01

    Roč. 19, č. 4 (2017), č. článku 045603. ISSN 2040-8978 R&D Projects: GA MŠk(CZ) LO1206 Institutional support: RVO:61389021 Keywords : volume gratings * holography * dispersion * refractive index modulation Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 1.741, year: 2016 http://iopscience.iop.org/article/10.1088/2040-8986/aa6092/meta

  10. Photon Dispersion in a Supernova Core

    OpenAIRE

    Kopf, A.; Raffelt, G.

    1997-01-01

    While the photon forward-scattering amplitude on free magnetic dipoles (e.g. free neutrons) vanishes, the nucleon magnetic moments still contribute significantly to the photon dispersion relation in a supernova (SN) core where the nucleon spins are not free due to their interaction. We study the frequency dependence of the relevant spin susceptibility in a toy model with only neutrons which interact by one-pion exchange. Our approach amounts to calculating the photon absorption rate from the ...

  11. Structural investigation of biogenic ferrihydrite nanoparticles dispersion

    International Nuclear Information System (INIS)

    Balasoiu, M.; Ishchenko, L.A.; Stolyar, S.V.; Iskhakov, R.S.; Rajkher, Yu.L.; Kuklin, A.I.; Solov'ev, D.V.; Arzumanyan, G.M.; Kurkin, T.S.; Aranghel, D.

    2010-01-01

    Structural properties of biogenic ferrihydrite nanoparticles produced by bacteria Klebsiella oxytoca are investigated. Investigations of morphology and size of particles dispersed in water by means of high-resolution transmission electron microscopy and small angle X-ray scattering measurements were performed. By model calculations followed by fitting procedure the structural parameters of a cylinder of radius R = (4.87 ± 0.02) nm and height L = (2.12 ± 0.04) nm are obtained

  12. Aqueous solution dispersement of carbon nanotubes

    Science.gov (United States)

    Kim, Jae-Woo (Inventor); Park, Cheol (Inventor); Choi, Sang H. (Inventor); Lillehei, Peter T. (Inventor); Harrison, Joycelyn S. (Inventor)

    2011-01-01

    Carbon nanotubes (CNTs) are dispersed in an aqueous buffer solution consisting of at least 50 weight percent water and a remainder weight percent that includes a buffer material. The buffer material has a molecular structure defined by a first end, a second end, and a middle disposed between the first and second ends. The first end is a cyclic ring with nitrogen and oxygen heteroatomes, the middle is a hydrophobic alkyl chain, and the second end is a charged group.

  13. Fluff-thieving birds sabotage seed dispersal

    OpenAIRE

    Rohwer, Vanya G.; Pauw, Anton; Martin, Paul R.

    2017-01-01

    Characterizing many species interactions as mutualisms can be misleading because some members of the interaction derive greater fitness benefits at the expense of other members. We provide detailed natural history data on a suspected bird?plant mutualism in South Africa where many species of birds use fluffy Eriocephalus seed material to construct their nests, potentially dispersing seeds for the plant. We focus on a common bird, Prinia maculosa, which invests heavily in gathering Eriocephalu...

  14. Dispersion of contaminants in saturated porous media

    International Nuclear Information System (INIS)

    Moltyaner, G.L.; Poisson, J.M.

    1987-10-01

    The main objective of this paper is to outline the experimental and theoretical investigations performed in an attempt to validate the applicability of finite element based numerical models for the prediction of the behaviour of a conservative tracer at the Twin Lake aquifer, Chalk River Nuclear Laboratories, Chalk River, Ontario. The essential point is that the 3/4 of a million data points obtained at the Twin Lake site from a 40 m natural gradient tracer test provide a unique opportunity for quantifying the system variability and for testing finite element models of the dispersion process. The subject of this discussion is the advection-dispersion model of contaminant transport - its equation and solution by the Galerkin finite element method. The report gives a brief description of the experimental data and the methods for the estimation of transport parameters. Scales of averaging associated with the conceptual formulation of the dispersion process, measurement of process variables, parameter estimation and the numerical models are discussed. The compatibility between the scales is emphasized as a major requirement for predictive modelling. The developed finite element model of the radioiodine transport describes the overall behaviour of the tracer plume but lacks the capability to simulate the fingerlike spreading of the plume due to the fact that the grid does not have an adequately fine space discretization. Unfortunately, a refinement of the grid spacing is limited by the size of the site computer memory. For the advection-dominated transport, as that encountered at the Twin Lake aquifer, the failure to satisfy fine mesh requirement causes numerical dispersion. In general, it was concluded that the conventional finite element model may produce accurate simulation of the tracer cloud provided that the adequately fine space discretization of the grid compatible with the support scale of measurements and the adequately fine time discretization are made. This

  15. CONCRETE BASED ON MODIFIED DISPERSE CEMENT SYSTEM

    Directory of Open Access Journals (Sweden)

    D. V. Rudenko

    2016-08-01

    Full Text Available Purpose. The article considers definition of the bond types occurring in a modified cement concrete matrix, and the evaluation of the quality of these links in a non-uniform material to determine the geometrical and physical relationships between the structure and the cement matrix modifiers. Methodology. To achieve this purpose the studies covered the microstructure of dispersed modified concrete cement matrix, the structure formation mechanism of the modified cement concrete system of natural hardening; as well as identification of the methods of sound concrete strength assessment. Findings. The author proposed a model of the spatial structure of the concrete cement matrix, modified by particulate reinforcement crystal hydrates. The initial object of study is a set of volume elements (cells of the cement matrix and the system of the spatial distribution of reinforcing crystallohydrates in these volume elements. It is found that the most dangerous defects such as cracks in the concrete volume during hardening are formed as a result of internal stresses, mainly in the zone of cement matrix-filler contact or in the area bordering with the largest pores of the concrete. Originality. The result of the study is the defined mechanism of the process of formation of the initial strength and stiffness of the modified cement matrix due to the rapid growth of crystallohydrates in the space among the dispersed reinforcing modifier particles. Since the lack of space prevents from the free growth of crystals, the latter cross-penetrate, forming a dense structure, which contributes to the growth of strength. Practical value. Dispersed modifying cement matrix provides a durable concrete for special purposes with the design performance characteristics. The developed technology of dispersed cement system modification, the defined features of its structure formation mechanism and the use of congruence principle for the complex of technological impacts of physical

  16. Evaluation of hovercraft for dispersant application

    Energy Technology Data Exchange (ETDEWEB)

    Dickens, D; Belore, R; Buist, I; Humphrey, B

    1988-01-01

    A series of field trials were carried out in Vancouver, Canada in July and August 1986 to determine whether or not hovercraft should be considered for dispersant application. Questions are: the ability of the hovercraft to ''fly'' over an oil slick at high speed without displacing the oil out of the path, the potential for using the hovercraft to impart vertical mixing energy into the water column to aid in the dispersant process and, the ability to mount a suitable spray boom and obtain a uniform spray pattern across the swath width. The field trials and subsequent interpretation of results provide positive answers to the first and second question. The question of mixing energy requires some qualification. The hovercraft contributes considerable mixing energy to the immediate water surface through air entrainment but this effect is short lived and there does not appear to be significant long term vertical mixing in the hovercraft wake. Recommendations are made for operating procedures and boom mounting which should ensure a uniform drop size and dose rate across a swath up to 18 m. The cushion air escaping from around the craft perimeter is not an important factor in adversly affecting the dispersant spray pattern. Depending on the type of machine available, hovcercraft have the capability of treating up to a 1km/sup 2/ slick between loads, at average speeds in the 15 to 25 knot range. The inherent advantages of high transit speed to the site (up to 45 Knots), amphibious operation (i.e. not draft limited) and lack of ceiling or visibility restrictions provide hovercarft with unique capabilities in the dispersant application role. Two patents relating to the process have been abstracted. Appendix B gives the sprecifications of two different models of hovercrafts. 14 refs., 29 figs., 6 tabs.

  17. Plasma Dispersion Functions for Complex Frequencies

    International Nuclear Information System (INIS)

    Pavlov, S. S.; Castejon, F.

    2005-01-01

    Plasma dispersion functions for complex wave propagation frequency in the weak relativistic regime for arbitrary longitudinal refractive index are estimated and presented in this work. These functions, that are know as Shkarofsky functions in the case of real frequency, are estimated using a new method that avoids the singularities that appear in previous calculations shown in the preceding literature. These results can be used to obtain the properties of plasma instabilities in the weakly relativistic regime. (Author) 14 refs

  18. Employment Effects of Spatial Dispersal of Refugees

    OpenAIRE

    Anna Piil Damm; Michael Rosholm

    2006-01-01

    Spatial dispersal policies may influence labour market integration of refugees through two mechanisms. First, it may affect the local job offer arrival rate, and second, it may affect place utility. We investigate the second mechanism theoretically by formulating a partial search model in which an individual searches simultaneously for a job and for a new residential location. The model predicts that the reservation wage for local jobs is decreasing in place utility. We argue that spatial dis...

  19. Dispersion fuel for nuclear research facilities

    International Nuclear Information System (INIS)

    Kushtym, A.V.; Belash, M.M.; Zigunov, V.V.; Slabospitska, O.O.; Zuyok, V.A.

    2017-01-01

    Designs and process flow sheets for production of nuclear fuel rod elements and assemblies TVS-XD with dispersion composition UO_2+Al are presented. The results of fuel rod thermal calculation applied to Kharkiv subcritical assembly and Kyiv research reactor VVR-M, comparative characteristics of these fuel elements, the results of metallographic analyses and corrosion tests of fuel pellets are given in this paper

  20. Longitudinal ultrasonic waves dispersion in bars

    International Nuclear Information System (INIS)

    Suarez Antola, R.

    2001-01-01

    The exhibition intends to review some aspects of the propagation of the longitudinal ultrasonic pulses shortly in bars of traverse section uniform.Aspects they are part of the denominated geometric dispersion of the pulses.This phenomenon It can present like an additional complication in the ultrasonic essay of low frequency of thin pieces in structures and machines but takes place former ex professed in some applications of the wave guides been accustomed to in the prosecution of signs

  1. Oxide dispersion-strengthened ferritic alloys

    International Nuclear Information System (INIS)

    Asbroeck, P. van.

    1976-10-01

    The publication gives the available data on the DTO2 dispersion-strengthened ferritic alloy developed at C.E.N./S.C.K. Mol, Belgium. DTO2 is a Fe-Cr-Mo ferritic alloy, strengthened by addition of titanium oxide and of titanium leading to the formation of Chi phase. It was developed for use as canning material for fast breeder reactors. (author)

  2. Wave modulation in a nonlinear dispersive medium

    International Nuclear Information System (INIS)

    Kim, Y.C.; Khadra, L.; Powers, E.J.

    1980-01-01

    A model describing the simultaneous amplitude and phase modulation of a carrier wave propagating in a nonlinear dispersive medium is developed in terms of nonlinear wave-wave interactions between the sidebands and a low frequency wave. It is also shown that the asymmetric distribution of sidebands is determined by the wavenumber dependence of the coupling coefficient. Digital complex demodulation techniques are used to study modulated waves in a weakly ionized plasma and the experimental results support the analytical model

  3. Manufacturing Experience for Oxide Dispersion Strengthened Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Wendy D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Doherty, Ann L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Henager, Charles H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Montgomery, Robert O. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Omberg, Ronald P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Smith, Mark T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Webster, Ryan A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-22

    This report documents the results of the development and the manufacturing experience gained at the Pacific Northwest National Laboratories (PNNL) while working with the oxide dispersion strengthened (ODS) materials MA 956, 14YWT, and 9YWT. The Fuel Cycle Research and Development program of the Office of Nuclear Energy has implemented a program to develop a Uranium-Molybdenum metal fuel for light water reactors. ODS materials have the potential to provide improved performance for the U-Mo concept.

  4. Modeling of Rayleigh wave dispersion in Iberia

    Directory of Open Access Journals (Sweden)

    José Badal

    2011-01-01

    Full Text Available Phase and group velocities of 15–70 s Rayleigh waves propagating across the Iberian Peninsula have been transformed into local dispersion curves by linear inversion of travel times. The procedure permits that the waveform dispersion to be obtained as a continuous period-dependent velocity function at grid points belonging to the area probed by the waves, thus providing phase- and group-velocity contour maps for several periods within the interval of interest. The regionalization process rests on a homogeneous initial data set in which the number of observations remains almost constant for all periods of reference. Damped least-squares inversion of the local dispersion curves for shear-wave velocity structure is performed to obtain depth-dependent S-wave velocity profiles at the grid points covering the model region. The reliability of the results should improve significantly owing to the use of phase and group velocities simultaneously. On this basis, we have built horizontal depth sections that give an updated view of the seismic velocity structure of the peninsula at lithospheric and upper mantle depths (20–200 km. After averaging all the pure-path S-wave velocities previously determined at each grid point, the velocity-depth models so obtained for major tectonic units allow the comparison between the Hercynian basement and other areas of Mesozoic folding and Tertiary basins.

  5. Uranium Dispersion and Dosimetry (UDAD) Code

    International Nuclear Information System (INIS)

    Momeni, M.H.; Yuan, Y.; Zielen, A.J.

    1979-05-01

    The Uranium Dispersion and Dosimetry (UDAD) Code provides estimates of potential radiation exposure to individuals and to the general population in the vicinity of a uranium processing facility. The UDAD Code incorporates the radiation dose from the airborne release of radioactive materials, and includes dosimetry of inhalation, ingestion, and external exposures. The removal of raioactive particles from a contaminated area by wind action is estimated, atmospheric concentrations of radioactivity from specific sources are calculated, and source depletion as a result of deposition, fallout, and ingrowth of radon daughters are included in a sector-averaged Gaussian plume dispersion model. The average air concentration at any given receptor location is assumed to be constant during each annual release period, but to increase from year to year because of resuspension. Surface contamination and deposition velocity are estimated. Calculation of the inhalation dose and dose rate to an individual is based on the ICRP Task Group Lung Model. Estimates of the dose to the bronchial epithelium of the lung from inhalation of radon and its short-lived daughters are calculated based on a dose conversion factor from the BEIR report. External radiation exposure includes radiation from airborne radionuclides and exposure to radiation from contaminated ground. Terrestrial food pathways include vegetation, meat, milk, poultry, and eggs. Internal dosimetry is based on ICRP recommendations. In addition, individual dose commitments, population dose commitments, and environmental dose commitments are computed. This code also may be applied to dispersion of any other pollutant

  6. Casein Micelle Dispersions under Osmotic Stress

    Science.gov (United States)

    Bouchoux, Antoine; Cayemitte, Pierre-Emerson; Jardin, Julien; Gésan-Guiziou, Geneviève; Cabane, Bernard

    2009-01-01

    Abstract Casein micelles dispersions have been concentrated and equilibrated at different osmotic pressures using equilibrium dialysis. This technique measured an equation of state of the dispersions over a wide range of pressures and concentrations and at different ionic strengths. Three regimes were found. i), A dilute regime in which the osmotic pressure is proportional to the casein concentration. In this regime, the casein micelles are well separated and rarely interact, whereas the osmotic pressure is dominated by the contribution from small residual peptides that are dissolved in the aqueous phase. ii), A transition range that starts when the casein micelles begin to interact through their κ-casein brushes and ends when the micelles are forced to get into contact with each other. At the end of this regime, the dispersions behave as coherent solids that do not fully redisperse when osmotic stress is released. iii), A concentrated regime in which compression removes water from within the micelles, and increases the fraction of micelles that are irreversibly linked to each other. In this regime the osmotic pressure profile is a power law of the residual free volume. It is well described by a simple model that considers the micelle to be made of dense regions separated by a continuous phase. The amount of water in the dense regions matches the usual hydration of proteins. PMID:19167314

  7. Axial Dispersion during Hanford Saltcake Washing

    International Nuclear Information System (INIS)

    Josephson, Gary B.; Geeting, John GH; Lessor, Delbert L.; Barton, William B.

    2006-01-01

    Clean up of Hanford salt cake wastes begins with dissolution retrieval of the sodium rich salts that make up the dominant majority of mass in the tanks. Water moving through the porous salt cake dissolves the soluble components and also displaces the soluble radionuclides (e.g. 137Cs and 99TcO4- ). The separation that occurs from this displacement, known as Selective dissolution, is an important component in Hanford?s pretreatment of low activity wastes for subsequent Supplemental treatment. This paper describes lab scale testing conducted to evaluate Selective dissolution of cesium from non-radioactive Hanford tank 241-S-112 salt cake simulant containing the primary chemicals found the actual tank. An modified axial dispersion model with increasing axial dispersion was developed to predict cesium removal. The model recognizes that water dissolves the salt cake during washing, which causes an increase in the axial dispersion during the wash. This model was subsequently compared with on-line cesium measurements from the retrieval of tank 241-S-112. The model had remarkably good agreement with both the lab scale and full scale data

  8. Platoon Dispersion Analysis Based on Diffusion Theory

    Directory of Open Access Journals (Sweden)

    Badhrudeen Mohamed

    2017-01-01

    Full Text Available Urbanization and gro wing demand for travel, causes the traffic system to work ineffectively in most urban areas leadin g to traffic congestion. Many approaches have been adopted to address this problem, one among them being the signal co-ordination. This can be achieved if the platoon of vehicles that gets discharged at one signal gets green at consecutive signals with minimal delay. However, platoons tend to get dispersed as they travel and this dispersion phenomenon should be taken into account for effective signal coordination. Reported studies in this area are from the homogeneous and lane disciplined traffic conditions. This paper analyse the platoon dispersion characteristics under heterogeneous and lane-less traffic conditions. Out of the various modeling techniques reported, the approach based on diffusion theory is used in this study. The diffusion theory based models so far assumed thedata to follow normal distribution. However, in the present study, the data was found to follow lognormal distribution and hence the implementation was carried out using lognormal distribution. The parameters of lognormal distribution were calibrated for the study condition. For comparison purpose, normal distribution was also calibrated and the results were evaluated. It was foun d that model with log normal distribution performed better in all cases than the o ne with normal distribution.

  9. Delayed shear enhancement in mesoscale atmospheric dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Moran, M.D. [Atmospheric Environment Service, Ontario (Canada); Pielke, R.A. [Colorado State Univ., Fort Collins, CO (United States)

    1994-12-31

    Mesoscale atmospheric dispersion (MAD) is more complicated than smaller-scale dispersion because the mean wind field can no longer be considered steady or horizontally homogeneous over mesoscale time and space scales. Wind shear also plays a much more important role on the mesoscale: horizontal dispersion can be enhanced and often dominated by vertical wind shear on these scales through the interaction of horizontal differential advection and vertical mixing. Just over 30 years ago, Pasquill suggested that this interaction need not be simultaneous and that the combination of differential horizontal advection with delayed or subsequent vertical mixing could maintain effective horizontal diffusion in spite of temporal or spatial reductions in boundary-layer turbulence intensity. This two-step mechanism has not received much attention since then, but a recent analysis of observations from and numerical simulations of two mesoscale tracer experiments suggests that delayed shear enhancement can play an important role in MAD. This paper presents an overview of this analysis, with particular emphasis on the influence of resolvable vertical shear on MAD in these two case studies and the contributions made by delayed shear enhancement.

  10. Contractility Dispersion in Long QT Syndrome

    Directory of Open Access Journals (Sweden)

    MH Nikoo

    2009-09-01

    Full Text Available Background: Previous studies, using M mode echocardiography, provided unexpected evidence of a mechanical alteration in patients with long QT syndrome. The aim of this study was to evaluate entire left ventricular (LV wall motion characteristics in patients with long QT syndrome using tissue Doppler imaging. Methods: We enrolled 17 patients with congenital long QT syndrome [11 female and 6 male], aged 21 to 45 years. 10 subjects without cardiac disease were also selected as a control group. Two-dimensional tissue Doppler imaging (TDI recording of the LV was obtained from the basal and mid-segments from apical four-chamber, two-chamber, and long-axis views. ‘Myocardial Contraction Duration’ [MCD] was defined as the time from start of R wave on ECG to end of S wave on TDI. MCD was measured in the six LV wall positions: septal, anteroseptal, lateral, inferior, posterior and anterior positions.Results: LV contractility dispersion was significantly greater in long QT syndrome patients compared to control group [0.051 ± 0.011 vs. 0.016 ± 0.06; P < 0.001]. Conclusion: Our study evaluated left ventricular dispersion of contractility duration in patients with long QT syndrome. This mechanical dispersion may be a reflection of the inhomogeneity of repolarisation in the long QT syndrome.

  11. Jet noise reduction via dispersed phase injection

    Science.gov (United States)

    Greska, Brent; Krothapalli, Anjaneyulu; Arakeri, Vijay

    2001-11-01

    A recently developed hot jet aeroacoustics facility at FMRL,FAMU-FSU College of Engineering has been used to study the far field noise characteristics of hot supersonic jets as influenced by the injection of a dispersed phase with low mass loading.The measured SPL from a fully expanded Mach 1.36 hot jet shows a peak value of about 139 dB at 40 deg from the jet axis.By injecting atomized water,the SPL are reduced in the angular region of about 30 deg to 50 deg with the maximum reduction being about 2 dB at 40 deg.However,with the use of non atomized aqueous polymer solution as a dispersed phase the noise levels are reduced over all angular positions by at least 1 dB with the maximum reduction being about 3 dB at 40 deg.The injection of a dispersed phase readily kills the screech; the initial results show promise and optimization studies are underway to find methods of further noise reduction.

  12. Temporal variations in atmospheric dispersion at Hanford

    International Nuclear Information System (INIS)

    Ramsdell, J.V.; Burk, K.W.

    1990-01-01

    Climatological data are frequently used to estimate atmospheric dispersion factors for historical periods and for future releases for which adequate meteorological data are unavailable. This practice routinely leads to questions concerning the representativeness of data used. The work described here was performed to provide a basis for answering these questions at the U.S. Department of Energy's Hanford Site in eastern Washington. Atmospheric transport and diffusion near Hanford have been examined using a Lagrangian puff dispersion model and hourly meteorological data from the Hanford Meteorological Station and a network of 24 surface wind stations for a 5-yr period. Average normalized monthly concentrations were computed at 2.5-km intervals on a 31 by 31 grid from January 1983 through 1987, assuming an elevated release in the 200-East Area. Monthly average concentrations were used to determine 5-yr mean pattern and monthly mean patterns and the interannual variability about each pattern. Intra-annual and diurnal variations in dispersion factors are examined for six locations near Hanford

  13. Chaotic Lagrangian models for turbulent relative dispersion.

    Science.gov (United States)

    Lacorata, Guglielmo; Vulpiani, Angelo

    2017-04-01

    A deterministic multiscale dynamical system is introduced and discussed as a prototype model for relative dispersion in stationary, homogeneous, and isotropic turbulence. Unlike stochastic diffusion models, here trajectory transport and mixing properties are entirely controlled by Lagrangian chaos. The anomalous "sweeping effect," a known drawback common to kinematic simulations, is removed through the use of quasi-Lagrangian coordinates. Lagrangian dispersion statistics of the model are accurately analyzed by computing the finite-scale Lyapunov exponent (FSLE), which is the optimal measure of the scaling properties of dispersion. FSLE scaling exponents provide a severe test to decide whether model simulations are in agreement with theoretical expectations and/or observation. The results of our numerical experiments cover a wide range of "Reynolds numbers" and show that chaotic deterministic flows can be very efficient, and numerically low-cost, models of turbulent trajectories in stationary, homogeneous, and isotropic conditions. The mathematics of the model is relatively simple, and, in a geophysical context, potential applications may regard small-scale parametrization issues in general circulation models, mixed layer, and/or boundary layer turbulence models as well as Lagrangian predictability studies.

  14. Meteorological Uncertainty of atmospheric Dispersion model results (MUD)

    DEFF Research Database (Denmark)

    Havskov Sørensen, Jens; Amstrup, Bjarne; Feddersen, Henrik

    The MUD project addresses assessment of uncertainties of atmospheric dispersion model predictions, as well as optimum presentation to decision makers. Previously, it has not been possible to estimate such uncertainties quantitatively, but merely to calculate the 'most likely' dispersion scenario....

  15. The role of individual variation in marine larval dispersal

    KAUST Repository

    Nanninga, Gerrit B.; Berumen, Michael L.

    2014-01-01

    individuals may shape heterogeneity in patterns of connectivity. The concept of context- and condition-dependent dispersal describes the balance between the costs and benefits of dispersal that arises from the interaction of temporal and spatial landscape

  16. Marine Dispersal Scales Are Congruent over Evolutionary and Ecological Time

    KAUST Repository

    Pinsky, Malin L.; Saenz-Agudelo, Pablo; Salles, Océ ane C.; Almany, Glenn R.; Bode, Michael; Berumen, Michael L.; André fouë t, Serge; Thorrold, Simon R.; Jones, Geoffrey P.; Planes, Serge

    2016-01-01

    -distance dispersal are based on direct ecological observations of dispersing individuals, while indirect evolutionary estimates often suggest substantially greater homogeneity among populations. Reconciling these two approaches and their seemingly competing

  17. Dispersal and biogeography of silica-scaled chrysophytes

    DEFF Research Database (Denmark)

    Kristiansen, Jørgen

    2008-01-01

    The silica-scaled chrysophytes—here mainly represented by the freshwater genera Mallomonas and Synura—have special problems in dispersal from one habitat to another because they cannot tolerate desiccation. Their dispersal is limited by the fragile construction and aquatic habit. Dispersal from one...... water body to another involves dangerous changes of the environment, and the ability to avoid desiccation during transport is crucial. So, air-borne and ectozoic dispersal by birds or mammals can only work at short distances. This danger may be avoided by endozoic dispersal of thick-walled cysts; as far....... The distribution of a species at a given time depends on several factors: dispersal capacity—available vectors—suitable available habitats—and most important: sufficient time for dispersal. It is remarkable that the chrysophytes—in spite of their fragile cell construction and apparently low dispersal capacity...

  18. Dispersant effectiveness in the field on fresh oils and emulsions

    International Nuclear Information System (INIS)

    Lunel, T.; Davies, L.

    1996-01-01

    A detailed data set on the effectiveness of dispersants on fresh oils and emulsions, was presented. The data set could be used to calibrate laboratory dispersant tests and dispersion models so that oil spill response teams would have accurate information to make decisions regarding remediation processes. AEA Technology developed steady state continuous release experiments to provide a data set with quantitative measures of dispersant effectiveness in the field. The Sea Empress incident was closely monitored in order to compare the quantification obtained through field trials. It was noted that the prediction of the percentage of oil dispersed chemically is not the only indication of whether or not to use a dispersant. The important determinant to consider should be the extent to which the natural dispersion process would be enhanced by dispersant application. 17 refs., 5 tabs., 18 figs

  19. Skeletonized wave equation of surface wave dispersion inversion

    KAUST Repository

    Li, Jing; Schuster, Gerard T.

    2016-01-01

    We present the theory for wave equation inversion of dispersion curves, where the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. Similar to wave-equation travel

  20. Studying the factors affecting urban dispersion in mashhad metropolis

    African Journals Online (AJOL)

    economic, social, and physical aspects including increased air pollution, potential deterioration within ... solutions to control this problem. The tools used in ... Key words: urban dispersion, technology, roots of Mashhad dispersion, the price of

  1. Dispersion Engineering of Bose-Einstein Condensates

    Science.gov (United States)

    Khamehchi, Mohammad Amin

    The subject of this dissertation is engineering the dispersion relation for dilute Bose-Einstein condensates (BECs). When a BEC is immersed into suitably tailored laser fields its dispersion can be strongly modified. Prominent examples for such laser fields include optical lattice geometries and Raman dressing fields. The ability to engineer the dispersion of a BEC allows for the investigation of a range of phenomena related to quantum hydrodynamics and condensed matter. In the first context, this dissertation studies the excitation spectrum of a spin-orbit coupled (SOC) BEC. The spin-orbit coupling is generated by " dressing" the atoms with two Raman laser fields. The excitation spectrum has a Roton-like feature that can be altered by tuning the Raman laser parameters. It is demonstrated that the Roton mode can be softened, but it does not reach the ground state energy for the experimental conditions we had. Furthermore, the expansion of SOC BECs in 1D is studied by relaxing the trap allowing the BEC to expand in the SOC direction. Contrary to the findings for optical lattices, it is observed that the condensate partially occupies quasimomentum states with negative effective mass, and therefore an abrupt deceleration is observed although the mean field force is along the direction of expansion. In condensed-matter systems, a periodic lattice structure often plays an important role. In this context, an alternative to the Raman dressing scheme can be realized by coupling the s- and p- bands of a static optical lattice via a weak moving lattice. The bands can be treated as pseudo-spin states. It is shown that similar to the dispersion relation of a Raman dressed SOC, the quasimomentum of the ground state is different from zero. Coherent coupling of the SOC dispersion minima can lead to the realization of the stripe phase even though it is not the thermodynamic ground state of the system. Along the lines of studying the hydrodynamics of BECs, three novel

  2. Control of Dispersion in Hollow Core Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Roberts, John

    2007-01-01

    The dispersion of hollow core photonic crystal fibers can be tailored by modifying a single ring of holes in the cladding. The dispersion can be lowered and flattened, or alternatively greatly increased, in a controlled manner.......The dispersion of hollow core photonic crystal fibers can be tailored by modifying a single ring of holes in the cladding. The dispersion can be lowered and flattened, or alternatively greatly increased, in a controlled manner....

  3. Analytical solutions of advection-dispersion equation for varying ...

    African Journals Online (AJOL)

    Analytical solutions are obtained for a one-dimensional advection–dispersion equation with variable coefficients in a longitudinal domain. Two cases are considered. In the first one the solute dispersion is time dependent along a uniform flow in a semi-infinite domain while in the second case the dispersion and the velocity ...

  4. Behavioral tradeoffs when dispersing across a patchy landscape.

    Science.gov (United States)

    Patrick A. Zollner; Steven L. Lima

    2005-01-01

    A better understanding of the behavior of dispersing animals will assist in determining the factors that limit their success and ultimately help improve the way dispersal is incorporated into population models. To that end, we used a simulation model to investigate three questions about behavioral tradeoffs that dispersing animals might face: (i) speed of movement...

  5. Melt dispersion of thermoplastic polystyrene in polymer polyols

    NARCIS (Netherlands)

    2009-01-01

    Polystyrene is dispersed into a polyol via a mechanical dispersion process. A stabilizer is present to stabilize the dispersed polymer particles. The stabilizer includes a copolymer of (1) from 10 to 70% by weight of a branched polyol which has a molecular weight of from 4000 to 20,000, from 0.2 to

  6. Spatial characterization of catchment dispersion mechanisms in an urban context

    Science.gov (United States)

    Rossel, Florian; Gironás, Jorge; Mejía, Alfonso; Rinaldo, Andrea; Rodriguez, Fabrice

    2014-12-01

    Previous studies have examined in-depth the dispersion mechanisms in natural catchments. In contrast, these dispersion mechanisms have been studied little in urban catchments, where artificial transport elements and morphological arrangements are expected to modify travel times and mobilize excess rainfall from spatially distributed impervious sites. This has the ability to modify the variance of the catchment's travel times and hence the total dispersion. This work quantifies the dispersion mechanisms in an urban catchment using the theory of transport by travel times as represented by the Urban Morpho-climatic Instantaneous Unit Hydrograph (U-McIUH) model. The U-McIUH computes travel times based on kinematic wave theory and accounts explicitly for the path heterogeneities and altered connectivity patterns characteristic of an urban drainage network. The analysis is illustrated using the Aubinière urban catchment in France as a case study. We found that kinematic dispersion is dominant for small rainfall intensities, whereas geomorphologic dispersion becomes more dominant for larger intensities. The total dispersion scales with the drainage area in a power law fashion. The kinematic dispersion is dominant across spatial scales up to a threshold of approximately 2-3 km2, after which the geomorphologic dispersion becomes more dominant. Overall, overland flow is responsible for most of the dispersion in the catchment, while conduits tend to counteract the increase of the geomorphologic dispersion with a negative kinematic dispersion. Further study with other catchments is needed to asses if the latter is a general feature of urban drainage networks.

  7. Patterns and mechanisms of dispersal in a keystone seagrass species

    DEFF Research Database (Denmark)

    Jahnke, M.; Christensen, Asbjørn; Micu, D.

    2016-01-01

    •Z. noltei shows low genetic connectivity (from 10 s to 100 s of km) in the Black Sea.•Physical modelling of dispersal well agree with estimates of genetic connectivity.•Physical and genetic connectivity show possible but rare long distance dispersal.•Seeds get dispersed locally while shoots have...

  8. Dispersion of radioactive materials in air and water

    International Nuclear Information System (INIS)

    Tolksdorf, P.; Meurin, G.

    1976-01-01

    A review of current analytical methods for treating the dispersion of radioactive material in air and water is given. It is shown that suitable calculational models, based on experiments, exist for the dispersion in air. By contrast, the analysis of the dispersion of radioactive material in water still depends on the evaluation of experiments with site-specific models. (orig.) [de

  9. Rethinking the history of common walnut (Juglans regia L.) in Europe: Its origins and human interactions.

    Science.gov (United States)

    Pollegioni, Paola; Woeste, Keith; Chiocchini, Francesca; Del Lungo, Stefano; Ciolfi, Marco; Olimpieri, Irene; Tortolano, Virginia; Clark, Jo; Hemery, Gabriel E; Mapelli, Sergio; Malvolti, Maria Emilia

    2017-01-01

    Common walnut (Juglans regia L) is an economically important species cultivated worldwide for its high-quality wood and nuts. It is generally accepted that after the last glaciation J. regia survived and grew in almost completely isolated stands in Asia, and that ancient humans dispersed walnuts across Asia and into new habitats via trade and cultural expansion. The history of walnut in Europe is a matter of debate, however. In this study, we estimated the genetic diversity and structure of 91 Eurasian walnut populations using 14 neutral microsatellites. By integrating fossil pollen, cultural, and historical data with population genetics, and approximate Bayesian analysis, we reconstructed the demographic history of walnut and its routes of dispersal across Europe. The genetic data confirmed the presence of walnut in glacial refugia in the Balkans and western Europe. We conclude that human-mediated admixture between Anatolian and Balkan walnut germplasm started in the Early Bronze Age, and between western Europe and the Balkans in eastern Europe during the Roman Empire. A population size expansion and subsequent decline in northeastern and western Europe was detected in the last five centuries. The actual distribution of walnut in Europe resulted from the combined effects of expansion/contraction from multiple refugia after the Last Glacial Maximum and its human exploitation over the last 5,000 years.

  10. Evaluating Chemical Dispersant Efficacy In An Experimental Wave Tank: 1, Dispersant Effectiveness As A Function Of Energy Dissipation Rate

    Science.gov (United States)

    Numerous laboratory test systems have been developed for the comparison of efficacy between various chemical oil dispersant formulations. However, for the assessment of chemical dispersant effectiveness under realistic sea state, test protocols are required to produce hydrodynam...

  11. Fast Running Urban Dispersion Model for Radiological Dispersal Device (RDD) Releases: Model Description and Validation

    Energy Technology Data Exchange (ETDEWEB)

    Gowardhan, Akshay [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Atmospheric Release Advisory Center (NARAC); Neuscamman, Stephanie [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Atmospheric Release Advisory Center (NARAC); Donetti, John [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Atmospheric Release Advisory Center (NARAC); Walker, Hoyt [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Atmospheric Release Advisory Center (NARAC); Belles, Rich [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Atmospheric Release Advisory Center (NARAC); Eme, Bill [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Atmospheric Release Advisory Center (NARAC); Homann, Steven [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Atmospheric Release Advisory Center (NARAC); Simpson, Matthew [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Atmospheric Release Advisory Center (NARAC); Nasstrom, John [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Atmospheric Release Advisory Center (NARAC)

    2017-05-24

    Aeolus is an efficient three-dimensional computational fluid dynamics code based on finite volume method developed for predicting transport and dispersion of contaminants in a complex urban area. It solves the time dependent incompressible Navier-Stokes equation on a regular Cartesian staggered grid using a fractional step method. It also solves a scalar transport equation for temperature and using the Boussinesq approximation. The model also includes a Lagrangian dispersion model for predicting the transport and dispersion of atmospheric contaminants. The model can be run in an efficient Reynolds Average Navier-Stokes (RANS) mode with a run time of several minutes, or a more detailed Large Eddy Simulation (LES) mode with run time of hours for a typical simulation. This report describes the model components, including details on the physics models used in the code, as well as several model validation efforts. Aeolus wind and dispersion predictions are compared to field data from the Joint Urban Field Trials 2003 conducted in Oklahoma City (Allwine et al 2004) including both continuous and instantaneous releases. Newly implemented Aeolus capabilities include a decay chain model and an explosive Radiological Dispersal Device (RDD) source term; these capabilities are described. Aeolus predictions using the buoyant explosive RDD source are validated against two experimental data sets: the Green Field explosive cloud rise experiments conducted in Israel (Sharon et al 2012) and the Full-Scale RDD Field Trials conducted in Canada (Green et al 2016).

  12. Dispersion Distance and the Matter Distribution of the Universe in Dispersion Space.

    Science.gov (United States)

    Masui, Kiyoshi Wesley; Sigurdson, Kris

    2015-09-18

    We propose that "standard pings," brief broadband radio impulses, can be used to study the three-dimensional clustering of matter in the Universe even in the absence of redshift information. The dispersion of radio waves as they travel through the intervening plasma can, like redshift, be used as a cosmological distance measure. Because of inhomogeneities in the electron density along the line of sight, dispersion is an imperfect proxy for radial distance and we show that this leads to calculable dispersion-space distortions in the apparent clustering of sources. Fast radio bursts (FRBs) are a new class of radio transients that are the prototypical standard ping and, due to their high observed dispersion, have been interpreted as originating at cosmological distances. The rate of fast radio bursts has been estimated to be several thousand over the whole sky per day and, if cosmological, the sources of these events should trace the large-scale structure of the Universe. We calculate the dispersion-space power spectra for a simple model where electrons and FRBs are biased tracers of the large-scale structure of the Universe, and we show that the clustering signal could be measured using as few as 10 000 events. Such a survey is in line with what may be achieved with upcoming wide-field radio telescopes.

  13. NOISY DISPERSION CURVE PICKING (NDCP): a Matlab friendly suite package for fully control dispersion curve picking

    Science.gov (United States)

    Granados, I.; Calo, M.; Ramos, V.

    2017-12-01

    We developed a Matlab suite package (NDCP, Noisy Dispersion Curve Picking) that allows a full control over parameters to identify correctly group velocity dispersion curves in two types of datasets: correlograms between two stations or surface wave records from earthquakes. Using the frequency-time analysis (FTAN), the procedure to obtain the dispersion curves from records with a high noise level becomes difficult, and sometimes, the picked curve result in a misinterpreted character. For correlogram functions, obtained with cross-correlation of noise records or earthquake's coda, a non-homogeneous noise sources distribution yield to a non-symmetric Green's function (GF); to retrieve the complete information contained in there, NDCP allows to pick the dispersion curve in the time domain both in the causal and non-causal part of the GF. Then the picked dispersion curve is displayed on the FTAN diagram to in order to check if it matches with the maximum of the signal energy avoiding confusion with overtones or spike of noise. To illustrate how NDCP performs, we show exemple using: i) local correlograms functions obtained from sensors deployed into a volcanic caldera (Los Humeros, in Puebla, Mexico), ii) regional correlograms functions between two stations of the National Seismological Service (SSN, Servicio Sismológico Nacional in Spanish), and iii) surface wave seismic record for an earthquake located in the Pacific Ocean coast of Mexico and recorded by the SSN. This work is supported by the GEMEX project (Geothermal Europe-Mexico consortium).

  14. Partitioning of fresh crude oil between floating, dispersed and sediment phases: Effect of exposure order to dispersant and granular materials.

    Science.gov (United States)

    Boglaienko, Daria; Tansel, Berrin

    2016-06-15

    When three or more high and low energy substrates are mixed, wetting order can significantly affect the behavior of the mixture. We analyzed the phase distribution of fresh floating Louisiana crude oil into dispersed, settled and floating phases depending on the exposure sequence to Corexit 9500A (dispersant) and granular materials. In the experiments artificial sea water at salinity 34‰ was used. Limestone (2.00-0.300 mm) and quartz sand (0.300-0.075 mm) were used as the natural granular materials. Dispersant Corexit 9500A increased the amount of dispersed oil up to 33.76 ± 7.04%. Addition of granular materials after the dispersant increased dispersion of oil to 47.96 ± 1.96%. When solid particles were applied on the floating oil before the dispersant, oil was captured as oil-particle aggregates and removed from the floating layer. However, dispersant addition led to partial release of the captured oil, removing it from the aggregated form to the dispersed and floating phases. There was no visible oil aggregation with the granular materials when quartz or limestone was at the bottom of the flask before the addition of oil and dispersant. The results show that granular materials can be effective when applied from the surface for aggregating or dispersing oil. However, the granular materials in the sediments are not effective neither for aggregating nor dispersing floating oil. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Wave equation dispersion inversion using a difference approximation to the dispersion-curve misfit gradient

    KAUST Repository

    Zhang, Zhendong

    2016-07-26

    We present a surface-wave inversion method that inverts for the S-wave velocity from the Rayleigh wave dispersion curve using a difference approximation to the gradient of the misfit function. We call this wave equation inversion of skeletonized surface waves because the skeletonized dispersion curve for the fundamental-mode Rayleigh wave is inverted using finite-difference solutions to the multi-dimensional elastic wave equation. The best match between the predicted and observed dispersion curves provides the optimal S-wave velocity model. Our method can invert for lateral velocity variations and also can mitigate the local minimum problem in full waveform inversion with a reasonable computation cost for simple models. Results with synthetic and field data illustrate the benefits and limitations of this method. © 2016 Elsevier B.V.

  16. Pulse Propagation in Presence of Polarization Mode Dispersion and Chromatic Dispersion in Single Mode Fibers

    Directory of Open Access Journals (Sweden)

    Hassan Abid Yasser

    2013-01-01

    Full Text Available The presence of (first and second orders polarization mode dispersion (PMD, chromatic dispersion, and initial chirp makes effects on the propagated pulses in single mode fiber. Nowadays, there is not an accurate mathematical formula that describes the pulse shape in the presence of these effects. In this work, a theoretical study is introduced to derive a generalized formula. This formula is exactly approached to mathematical relations used in their special cases. The presence of second-order PMD (SOPMD will not affect the orthogonality property between the principal states of polarization. The simulation results explain that the interaction of the SOPMD components with the conventional effects (chromatic dispersion and chirp will cause a broadening/narrowing and shape distortion. This changes depend on the specified values of SOPMD components as well as the present conventional parameters.

  17. The Dispersion of Employees' Wage Increase and Firm Performance

    DEFF Research Database (Denmark)

    Grund, Christian; Westergård-Nielsen, Niels Chr.

    2008-01-01

    than the dispersion of wage levels. It is reasonable to expect greater dispersion of wage increases to be associated with higher monetary incentives, but also with increased perceptions of unfairness. The authors' analysis of linked employer-employee data from Denmark for the years 1992-97 shows......Previous studies examining intra-firm wage dispersion and firm performance have focused on wage levels. The authors of this study argue that for purposes of comparing wage dispersion's positive incentive effects with its adverse morale effects, the dispersion of wage increases is more revealing...

  18. Fundamentals of energy dispersive X-ray analysis

    CERN Document Server

    Russ, John C; Kiessling, R; Charles, J

    1984-01-01

    Fundamentals of Energy Dispersive X-ray Analysis provides an introduction to the fundamental principles of dispersive X-ray analysis. It presents descriptions, equations, and graphs to enable the users of these techniques to develop an intuitive and conceptual image of the physical processes involved in the generation and detection of X-rays. The book begins with a discussion of X-ray detection and measurement, which is accomplished by one of two types of X-ray spectrometer: energy dispersive or wavelength dispersive. The emphasis is on energy dispersive spectrometers, given their rather wid

  19. Dispersion factors - tables and diagrams for the Karlsruhe site

    International Nuclear Information System (INIS)

    Papadopoulos, D.; Baer, M.; Honcu, S.

    1984-02-01

    Dispersion experiments were performed at the Nuclear Research Center for the Karlsruhe site. The evaluation of these experiments allowed to determine the parameters of lateral or vertical atmospheric dispersions. This report is a compilation of tables and diagrams showing the dispersion factors calculated with the help of the dispersion parameters. These dispersion factors are valid for the Karlsruhe site. They have been normalized to 1 m/s wind speed and to 1 g/s (or 1 Bq/s) source strength. (orig.) [de

  20. Modelling Pollutant Dispersion in a Street Network

    Science.gov (United States)

    Salem, N. Ben; Garbero, V.; Salizzoni, P.; Lamaison, G.; Soulhac, L.

    2015-04-01

    This study constitutes a further step in the analysis of the performances of a street network model to simulate atmospheric pollutant dispersion in urban areas. The model, named SIRANE, is based on the decomposition of the urban atmosphere into two sub-domains: the urban boundary layer, whose dynamics is assumed to be well established, and the urban canopy, represented as a series of interconnected boxes. Parametric laws govern the mass exchanges between the boxes under the assumption that the pollutant dispersion within the canopy can be fully simulated by modelling three main bulk transfer phenomena: channelling along street axes, transfers at street intersections, and vertical exchange between street canyons and the overlying atmosphere. Here, we aim to evaluate the reliability of the parametrizations adopted to simulate these phenomena, by focusing on their possible dependence on the external wind direction. To this end, we test the model against concentration measurements within an idealized urban district whose geometrical layout closely matches the street network represented in SIRANE. The analysis is performed for an urban array with a fixed geometry and a varying wind incidence angle. The results show that the model provides generally good results with the reference parametrizations adopted in SIRANE and that its performances are quite robust for a wide range of the model parameters. This proves the reliability of the street network approach in simulating pollutant dispersion in densely built city districts. The results also show that the model performances may be improved by considering a dependence of the wind fluctuations at street intersections and of the vertical exchange velocity on the direction of the incident wind. This opens the way for further investigations to clarify the dependence of these parameters on wind direction and street aspect ratios.