Frontier

Distribution by Scientific Domains
Distribution within Humanities and Social Sciences

Kinds of Frontier

  • agricultural frontier
  • american frontier
  • efficient frontier
  • last frontier
  • new frontier
  • production frontier
  • research frontier
  • stochastic frontier
  • stochastic production frontier
  • technological frontier

  • Terms modified by Frontier

  • frontier analysis
  • frontier approach
  • frontier model
  • frontier molecular orbital
  • frontier orbital
  • frontier province
  • frontier techniques

  • Selected Abstracts


    URBAN-SYSTEM EVOLUTION ON THE FRONTIER OF THE ECUADORIAN AMAZON

    GEOGRAPHICAL REVIEW, Issue 4 2000
    Roy Ryder
    ABSTRACT. Like the North American frontier, Ecuador's Amazonian margin has advanced in periodic waves. But the impetus has been extremely varied, interlacing periods of socioeconomic crisis with times of prosperity. Recent events in eastern Ecuador confirm that urbanization is a fundamental component of frontier development in South America. The urbanization process is not a sign, however, of regional economic strength. Capital gains at the periphery are transferred to the nation's core region. Even the larger boom towns display little functional specialization; they are, instead, precariously dependent on employment in the public-service sector. Nonetheless, urban centers in the Ecuadorian Amazon continue to grow and to drain surrounding rural areas of younger and more educated individuals. [source]


    STRATEGY AND SHAREHOLDER VALUE CREATION: THE REAL OPTIONS FRONTIER

    JOURNAL OF APPLIED CORPORATE FINANCE, Issue 2 2000
    Martha Amram
    The current interest in real options reflects the dramatic increase in the uncertainty of the business environment. Viewed narrowly, the real options approach is the extension of financial option pricing models to the valuation of options on real (that is, nonfinancial) assets. More broadly, the real options approach is a way of thinking that helps managers formulate their strategic options,the future opportunities that are created by today's investments,while considering their likely effect on shareholder value. But if the real options framework promises to link strategy more closely to shareholder value creation, there are some major challenges on the frontier of application. In the first part of this paper, the authors tackle the question, "What is really new about real options, and how does the approach differ from other wellestablished ways to make strategic decisions under uncertainty?" This article provides a specific definition of real options that relies on the ability to track marketpriced risk. Using examples from oil exploration and pharmaceutical drug development, the authors also show how specific features of the industry and the application itself determine the usefulness of the real options approach. The second part of the paper addresses the question: Given the many differences between real and financial options, how should a real options application be framed? The authors examine the use of real options in the valuation of Internet companies to demonstrate the required judgment and tradeoffs in the framing of real options applications. The case of Webvan, an online grocer, is used to illustrate the inter-action between strategy, execution, and valuation. [source]


    SOCIAL DYNAMICS ON THE NORTHERN FRONTIER OF ROMAN BRITAIN

    OXFORD JOURNAL OF ARCHAEOLOGY, Issue 1 2005
    MIKE McCARTHY
    Summary. Despite much work on the frontier of Roman Britain, major questions concerned with society and settlement archaeology remain underinvestigated. Salient details of two major urban sites, Carlisle and Corbridge, both of which may shed further light on processes of settlement growth and decline, and which may ultimately contribute to a greater understanding of how the frontier worked, are summarized. At Carlisle, and probably also at Corbridge, settlement growth associated with forts was rapid and multi-tracked, but from the later second century AD changes took place associated, perhaps, with enhanced status and a growing sense of community. [source]


    I,Andy Clark COGNITIVE COMPLEXITY AND THE SENSORIMOTOR FRONTIER

    ARISTOTELIAN SOCIETY SUPPLEMENTARY VOLUME, Issue 1 2006
    Andy Clark
    ABSTRACT What is the relation between perceptual experience and the suite of sensorimotor skills that enable us to act in the very world we perceive? The relation, according to ,sensorimotor models' (O'Regan and Noë 2001, Noë 2004) is tight indeed. Perceptual experience, on these accounts, is enacted via skilled sensorimotor activity, and gains its content and character courtesy of our knowledge of the relations between (typically) movement and sensory stimulation. I shall argue that this formulation is too extreme, and that it fails to accommodate the substantial firewalls, dis-integrations, and special-purpose streamings that form the massed strata of human cognition. In particular, such strong sensorimotor models threaten to obscure the computationally potent insensitivity of key information-processing events to the full subtleties of embodied cycles of sensing and moving. [source]


    COMMENTS ON FACTOR PRICES AND INCOME DISTRIBUTION IN LESS INDUSTRIALISED ECONOMIES, 1870,1939: REFOCUSING ON THE FRONTIER

    AUSTRALIAN ECONOMIC HISTORY REVIEW, Issue 3 2007
    Knick HarleyArticle first published online: 7 OCT 200
    economic institutions; factor prices; frontier; globalisation A great deal of the current research into nineteenth- and twentieth-century globalisation has been focused through a neoclassical trade theory lens. Applying the Stopler-Samuelson paradigm from Heckscher-Ohlin trade theory, the result is an approach that sees price convergence as pivotal in defining, identifying, and measuring globalisation. This focus, however, obscures the implications of frontier incorporation and other insights achieved by viewing nineteenth-century globalisation as a mechanism whereby peripheral economies were incorporated into the core of organised economic activity. A frontier-centred perspective also reintroduces the role of economic institutions as a crucial element of economic growth and development. [source]


    AN APPLICATION OF MULTI-CRITERIA DECISION MAKING INCORPORATING STOCHASTIC PRODUCTION FRONTIERS: A CASE STUDY OF ORGANIC COFFEE PRODUCTION IN KONA, HAWAII

    NATURAL RESOURCE MODELING, Issue 1 2010
    TADAYOSHI MASUDA
    Abstract In this paper, we develop a land use allocation model to search for the optimal ratio of organic (nonchemical) and conventional (chemical-use) farming acreage. The idea is to incorporate stochastic production frontiers (SPFs) to a multi-criteria decision making (MCDM) model as technological constraints. The objectives of this model are to maximize net returns, minimize chemical inputs, and optimize organic inputs given environmental and ecological concerns. The compromise solutions suggest the desirable ratio of organic and conventional farming acreage and targetable operations for each farming system to improve regional welfare. This method was applied to the Kona coffee belt, Hawaii, and the analysis determined the optimal proportion of organic and conventional Kona coffee farming fields as 0.265 to 0.735 in terms of optimizing community benefits or regional welfare. [source]


    Leadership: a New Frontier in Conservation Science

    CONSERVATION BIOLOGY, Issue 4 2009
    JIM C. MANOLIS
    estrategia; influencia; liderazgo; manejo; política Abstract:,Leadership is a critical tool for expanding the influence of conservation science, but recent advances in leadership concepts and practice remain underutilized by conservation scientists. Furthermore, an explicit conceptual foundation and definition of leadership in conservation science are not available in the literature. Here we drew on our diverse leadership experiences, our reading of leadership literature, and discussions with selected conservation science leaders to define conservation-science leadership, summarize an exploratory set of leadership principles that are applicable to conservation science, and recommend actions to expand leadership capacity among conservation scientists and practitioners. We define 2 types of conservation-science leadership: shaping conservation science through path-breaking research, and advancing the integration of conservation science into policy, management, and society at large. We focused on the second, integrative type of leadership because we believe it presents the greatest opportunity for improving conservation effectiveness. We identified 8 leadership principles derived mainly from the "adaptive leadership" literature: recognize the social dimension of the problem; cycle frequently through action and reflection; get and maintain attention; combine strengths of multiple leaders; extend your reach through networks of relationships; strategically time your effort; nurture productive conflict; and cultivate diversity. Conservation scientists and practitioners should strive to develop themselves as leaders, and the Society for Conservation Biology, conservation organizations, and academia should support this effort through professional development, mentoring, teaching, and research. Resumen:,El liderazgo es una herramienta crítica para la expansión de la influencia de la ciencia de la conservación, pero los avances recientes en los conceptos y práctica del liderazgo son subutilizados por los científicos de la conservación. Más aun, en la literatura no hay una fundamentación conceptual ni definición de liderazgo en la ciencia de la conservación. Aquí nos basamos en nuestras experiencias de liderazgo, nuestra lectura de literatura sobre liderazgo y discusiones con líderes selectos de la ciencia de conservación para definir liderazgo para la ciencia de la conservación, resumir un conjunto exploratorio de principios de liderazgo aplicables a la ciencia de la conservación y recomendar acciones para expandir la capacidad de liderazgo entre los científicos y los practicantes de la conservación. Definimos dos tipos de liderazgo de la ciencia de la conservación: configuración de la ciencia de la conservación mediante investigación original, y avance hacia la integración del liderazgo en la ciencia de la conservación en la política, el manejo y la sociedad en general. Nos centramos en el segundo tipo de liderazgo porque consideramos que presenta la mejor oportunidad para mejorar la efectividad de la conservación. Identificamos ocho principios de liderazgo derivados principalmente de la literatura sobre "liderazgo adaptativo": reconocer la dimensión social del problema; alternar entre acción y reflexión frecuentemente; obtener y mantener atención; combinar fortalezas de múltiples líderes; extender el alcance mediante redes de relaciones; organizar el esfuerzo estratégicamente; evitar conflictos productivos y desarrollar la biodiversidad. Los científicos y los practicantes de la conservación deberían esforzarse para desarrollarse como líderes y la Sociedad para la Biología de la Conservación, las organizaciones de conservación y la academia deberían respaldar este esfuerzo mediante el desarrollo profesional, la tutoría, la enseñanza y la investigación. [source]


    Exploring the Frontier of Livelihoods Research

    DEVELOPMENT AND CHANGE, Issue 1 2005
    Leo De Haan
    This article discusses the value of livelihoods studies and examines the obstacles which have prevented it from making a greater contribution to understanding the lives of poor people over the past decade. After examining the roots of the livelihoods approach, two major challenges are explored: the conceptualization of the problem of access, and how to achieve a better understanding of the mutual link between livelihood opportunities and decision-making. The article concludes that access to livelihood opportunities is governed by social relations, institutions and organizations, and that power is an important (and sometimes overlooked) explanatory variable. In discussing the issue of access to livelihood opportunities, the authors note the occurrence of both strategic and unintentional behaviour and the importance of structural factors; they discuss concepts of styles and pathways, which try to cater for structural components and regularities; and they propose livelihood trajectories as an appropriate methodology for examining these issues. In this way, the article also sets the agenda for future livelihoods research. [source]


    Producing a Modern Agricultural Frontier: Firms and Cooperatives in Eastern Mato Grosso, Brazil

    ECONOMIC GEOGRAPHY, Issue 3 2006
    Wendy Jepson
    Abstract: In economic geography, explanations of emerging agricultural frontier regions are dominated by two theoretical perspectives: land-rent theory and political economy. This article advances current research by applying concepts from new institutional economics to reconcile these models. Drawing from a case of frontier expansion in eastern Mato Grosso state, I focus the debate on an institutional perspective. Two organizations, a colonization firm and an agricultural cooperative, are examined. The combined activities of cooperatives and firms reduced the overall costs of production in regions that are defined by high transactions costs (for example, land-tenure insecurity, poor links to the market, and imperfect information) and risk. Each organization linked individual farmers to necessary resources for commercial farming (for instance, land, capital, technology, and markets) and provided an organizational context for farmers to respond to land-tenure conflict and land degradation. The consequence was an increase in the marginal productivity of land, which translated into an expanded commercial agricultural frontier. [source]


    Synthesis and Reactions of Polynuclear Polyhydrido Rare Earth Metal Complexes Containing "(C5Me4SiMe3)LnH2" Units: A New Frontier in Rare Earth Metal Hydride Chemistry

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2007
    Zhaomin Hou
    Abstract A series of tetranuclear octahydrido rare earth metal complexes of general formula [(C5Me4SiMe3)Ln(,-H)2]4(THF)n (Ln = Sc, Y, Gd, Dy, Ho, Er, Tm, Lu; n = 0, 1, or 2) that contain C5Me4SiMe3 as an ancillary ligand have been prepared and structurally characterized. These hydride clusters are soluble in common organic solvents such as THF, toluene, and hexane, and maintain their tetranuclear framework in solution. Such polynuclear polyhydrido complexes exhibit extremely high and unique reactivity toward a variety of unsaturated substrates including CO, CO2, and nitriles. The reaction of these neutral polyhydrides with one equivalent of [Ph3C][B(C6F5)4] affords the corresponding cationic hydride clusters [(C5Me4SiMe3)4Ln4H7(THF)n][B(C6F5)4], which can act as catalysts for the syndiospecific polymerization of styrene and regio- and stereospecific cis -1,4-polymerization of 1,3-cyclohexadiene. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]


    Nordic Investments in the Former Soviet Baltic Frontier: A Survey of Firms and Selected Case Studies

    GEOGRAFISKA ANNALER SERIES B: HUMAN GEOGRAPHY, Issue 4 2000
    Harley Johansen
    Nordic companies have been leaders in the rapid expansion of Western business into Estonia, Latvia, Lithuania, and the St Petersburg area of Russia. While joint ventures were being developed prior to the demise of the USSR, investment rose sharply in early 1992. Our survey of companies from Nordic countries revealed a pattern of location and of adaptation to the conditions of former Soviet infrastructure, culture, politics and economy. Initial Nordic investment has renewed economic ties across the Baltic Sea, with inter-country links stronger between specific countries. Frustrations with changing government rules, communications, work ethic, quality expectations and other conditions were expressed in interviews with managers of Nordic companies in the Baltic area. Optimism was tempered by continued uncertainty about Russian governmental policies and market potential. [source]


    Soil organic carbon stock change due to land use activity along the agricultural frontier of the southwestern Amazon, Brazil, between 1970 and 2002

    GLOBAL CHANGE BIOLOGY, Issue 10 2010
    STOÉCIO M. F. MAIA
    Abstract The southwestern portion of the Brazilian Amazon arguably represents the largest agricultural frontier in the world, and within this region the states of Rondônia and Mato Grosso have about 24% and 32% of their respective areas under agricultural management, which is almost half of the total area deforested in the Brazilian Amazon biome. Consequently, it is assumed that deforestation in this region has caused substantial loss of soil organic carbon (SOC). In this study, the changes in SOC stocks due to the land use change and management in the southwestern Amazon were estimated for two time periods from 1970,1985 and 1985,2002. An uncertainty analysis was also conducted using a Monte Carlo approach. The results showed that mineral soils converted to agricultural management lost a total of 5.37 and 3.74 Tg C yr,1 between 1970,1985 and 1985,2002, respectively, along the Brazilian Agricultural Frontier in the states of Mato Grosso and Rondônia. Uncertainties in these estimates were ±37.3% and ±38.6% during the first and second time periods, respectively. The largest sources of uncertainty were associated with reference carbon (C) stocks, expert knowledge surveys about grassland condition, and the management factors for nominal and degraded grasslands. These results showed that land use change and management created a net loss of C from soils, however, the change in SOC stocks decreased substantially from the first to the second time period due to the increase in land under no-tillage. [source]


    Dispatches from the Last Frontier of Molecular and Cell Biology: Biosynthesis of Polysaccharides and Proteoglycans of the Cell Surface and Extracellular Matrix

    IUBMB LIFE, Issue 4 2002
    Bruce Stone
    No abstract is available for this article. [source]


    Across the EU Studies,New Regionalism Frontier: Invitation to a Dialogue

    JCMS: JOURNAL OF COMMON MARKET STUDIES, Issue 4 2010
    ALEX WARLEIGH-LACK
    This article notes a lack of communication between two broad schools of scholarship on regional integration: EU studies and analyses of the ,new regionalism'. It is argued that the existence of this divide, which is perpetrated by proponents of both schools, is an impediment to the elaboration of useful theory as well as being a missed opportunity. The benefits and problems of using the EU as a comparator in studies of regionalism are assessed. While the mistake of giving the EU analytical primacy as a benchmark or model is to be avoided, it is argued that careful treatment of accumulated insights from EU studies (including a proper re-inspection of classical integration theory) brings clear methodological and meta-theoretical benefits for the project of comparative regional integration scholarship. [source]


    On the Frontier of Adulthood: Theory, Research, and Public Policy.

    JOURNAL OF MARRIAGE AND FAMILY, Issue 1 2006
    & Rubén G. Rumbaut, Frank F. Furstenberg, Richard A. Settersten
    No abstract is available for this article. [source]


    Electron ionization mass spectrometric study of monomeric models of O -polysaccharides of Vibrio cholerae O:1, serotypes Ogawa and Inaba

    JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 9 2003
    Vladimír Ková
    Abstract Fragmentation mechanisms of electron ionization (EI) mass spectrometry of the title compounds have been elucidated by high-resolution (HR) mass spectrometric measurements of the elemental composition and measurements of the metastable transitions (B2/E, CID). The experimental results were interpreted with the help of Mass Frontier 3.0 software, which aided the elucidation of fragmentation mechanisms and helped to deduce structures of the ions formed. Characteristic under the conditions of EI-MS measurement was the production of protonated adducts. Three distinct pathways observed include the formation of oxonium type ions, the conjugated transfer of electrons in the pyranose ring, and cleavage of the acylamide side chains. By applying the results obtained, the molecular mass, as well as the structures of both the saccharide and acylamide side chain involved in related substances, can be determined. Copyright © 2003 John Wiley & Sons, Ltd. [source]


    Law at the American Frontier

    LAW & SOCIAL INQUIRY, Issue 4 2004
    Jeffrey R. Dudas
    [source]


    Untaming the Frontier in Anthropology, Archaeology, and History

    AMERICAN ANTHROPOLOGIST, Issue 3 2006
    THOMAS M. WILSON
    Untaming the Frontier in Anthropology, Archaeology, and History. Bradley J. Parker and Lars Rodseth, eds. Tucson: University of Arizona Press, 2005. 294 pp. [source]


    Living Islam: Muslim Religious Experience in Pakistan's North-West Frontier by Magnus Marsden

    AMERICAN ETHNOLOGIST, Issue 1 2010
    PNINA WERBNER
    No abstract is available for this article. [source]


    Chronic Pain in the Cancer Survivor: A New Frontier

    PAIN MEDICINE, Issue 2 2007
    Allen W. Burton MD
    ABSTRACT Objective., This monograph is intended to clarify the clinical problem of chronic pain in cancer patients. Design., A pertinent literature review on chronic pain syndromes in cancer patients was undertaken using Medline. Further, the treatment strategies for cancer versus chronic pain are contrasted and clarified. Results., With increasing cancer survivorship come new challenges in patient care. In the United States, the cancer-related death rate has dropped by 1.1% per year from 1993,2002. Seventy-five percent of children and two out of three adults will survive cancer, whereas 50 years ago just one out of four survived. The net effect of these trends and opportunities is a large and rapidly growing population of persons living longer with cancer and/or as cancer survivors. While agreement exists on the best strategies for assessment and treatment of most acute cancer pain syndromes, little consensus exists on the treatment of chronic pain in the patient with slowly progressive cancer or the cancer survivor. Conclusions., The landscape of "cancer pain" is shifting quickly into a chronic pain situation in many instances, thereby blurring previous lines of distinction in treatment strategies most suited for "chronic" versus "malignant" pain. Adopting chronic pain treatment strategies including pharmacologic and other pain control techniques, rehabilitation care, and psychological coping strategies may lead to optimal outcomes. Lastly, as cancer evolves into a chronic illness, with co-morbid conditions, recurrent cancer, and treatment toxicities from repeated antineoplastic therapies, pain management challenges in the oncologic patient continue to increase in complexity. [source]


    Healing History's Wounds: Reconciliation Communication Efforts to Build Community Between Minnesota Dakota (Sioux) and Non-Dakota Peoples

    PEACE & CHANGE, Issue 3 2002
    Sheryl L. Dowlin
    This article describes the moral conflict involved when two incompatible social worlds collided on America's Frontier in Minnesota in 1862. The result was the bloodiest and costliest Indian war and the largest mass execution in our history. The residue of hatred and misunderstanding persist to this day but is being ameliorated by long-term efforts toward reconciliation. These relationship building efforts are illustrated by a model and with examples of dialogue, collaboration, and communally shared experiences between the dominant culture and the Dakota people. It is believed that these efforts are gradually having an impact in healing the deep wounds between these estranged cultures. [source]


    British Atlantic, American Frontier: Spaces of Power in Early Modern British America, by Stephen J. Hornsby

    THE CANADIAN GEOGRAPHER/LE GEOGRAPHE CANADIEN, Issue 3 2006
    GRAEME WYNN
    No abstract is available for this article. [source]


    How the Indians Lost Their Land: Law and Power on the Frontier , By Stuart Banner

    THE HISTORIAN, Issue 2 2007
    F. Todd Smith
    No abstract is available for this article. [source]


    Family and Frontier in Colonial Brazil: Santana de Parnaíba, 1580,1822 , Alida C. Metcalf

    THE HISTORIAN, Issue 4 2006
    Judy Bieber
    No abstract is available for this article. [source]


    Daughtersof Mars: Army Officers' Wives and Military Culture on the American Frontier

    THE HISTORIAN, Issue 1 2005
    Anni P. Baker
    First page of article [source]


    Pushing the Dead into the Next Reproductive Frontier: Post Mortem Gamete Retrieval under the Uniform Anatomical Gift Act

    THE JOURNAL OF LAW, MEDICINE & ETHICS, Issue 2 2009
    Bethany SpielmanArticle first published online: 3 JUN 200
    In re Matter of Daniel Thomas Christy authorized post mortem gamete retrieval under the most recent revision of the Uniform Anatomical Gift Act. This article recommends that the National Conference of Commissioners on Uniform State Laws explicitly address the issue of post mortem gamete retrieval for reproductive purposes; that legislators specify whether their states will follow the Christy ruling; and that ethics committees and consultants prepare for the questions about human identity and self determination that post mortem gamete retrieval raises. [source]


    Investigating Firefly and Serenity: Science Fiction on the Frontier

    THE JOURNAL OF POPULAR CULTURE, Issue 4 2009
    Stephanie Eve Boone
    No abstract is available for this article. [source]


    Homosocial Desire on the Final Frontier: Kinship, the American Romance, and Deep Space Nine's "Erotic Triangles"

    THE JOURNAL OF POPULAR CULTURE, Issue 3 2003
    Lincoln Geraghty
    The Star Trek mission, to go where no one has gone before, has returned us to our own inner spaces. One could see the latest question raised by explorations in terms of how to respond when confronted by an awareness of irreducible difference concerning that which bounds and blinds individuals however they are conceived of and wherever they are. (Blair 1997, 88) [source]


    Making History at the Frontier

    ANNALS OF ANTHROPOLOGICAL PRACTICE, Issue 1 2006
    Christina Wasson
    This volume presents the stories of 11 women anthropologists whose career paths have successfully navigated the terrain of practice. Its overall goal is to help future generations of anthropologists who are initiating careers in practice, both women and men. Students in applied anthropology programs, and others considering careers in practice, are hungry for such information. A second goal is to highlight the contributions and concerns of women practitioners from the perspective of feminist anthropology. Three common threads run across the life histories of these authors: an integrated scholar-practitioner identity; improvisation; and a shared set of building blocks for constructing their lives. Brief histories of four forerunners are provided to provide historical depth. They illustrate the continuing importance of persistence and determination, as well as the possibility of having meaningful and satisfying careers by approaching life and work creatively in the face of various obstacles. [source]


    Optimal Structure of Technology Adoption and Creation: Basic versus Development Research in Relation to the Distance from the Technological Frontier,

    ASIAN ECONOMIC JOURNAL, Issue 3 2009
    Joonkyung Ha
    O31; O47 Many economists maintain that in order to advance economic growth Asian countries should focus more on basic research than on technology adoption, and more on the supply of skilled workers than the supply of unskilled workers. In this context, this paper presents a theoretical model and empirical evidence to explain the observation that a country in which the level of technology approaches the technology frontier tends to rely more on technology creation than adoption, and invest more in basic research than in development. The model shows that technology creation involves both basic and development research processes, whereas technology adoption uses only the latter process. Therefore, R&D investment in our model involves three different processes: basic research in technology creation, development in technology creation, and development in technology adoption. The results suggest first that the rate of growth is positively correlated with the level of basic research activities in the technology creation sector, if a country's technology gap with the technology frontier is small enough. Second, an increase in the efficiency of the education system for highly skilled workers raises the level of basic research and the rate of growth. Third, verifying these theoretical results, empirical analyses using panel data from Korea, Japan and Taipei, China show that the narrower the distance to the technological frontier, the higher the growth effect of basic R&D, which indicates that the share of basic R&D matters for economic growth. Finally, the results also show that the quality of tertiary education has a significantly positive effect on the productivity of R&D. [source]