1,195 research outputs found

    Observations beyond the 2-year impact window

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    In 2018, Clarivate Analytics, publisher of the Web of Science Journal Citation Reports (JCR), suppressed publication of the 2017 Journal Impact Factor (JIF) for three of the four journals that it then indexed in the academic field of history of economics. Clarivate judged one of the journals, History of Economic Ideas (HEI), to be the “donor” of citations that distorted the impact factors of the European Journal of the History of Economic Thought (EJHET) and the Journal of the History of Economic Thought (JHET). The other journal, History of Political Economy (HOPE), was not included in that judgment. Our purpose is to define the JIF, summarize the controversy that gave rise to this symposium, and discuss methodologically and historically some of the problems with the use of citation indexes in general and the JIF in particular. We show how these problems pertain differently to the scholarly field of the history of economics than to economics in general. In so doing we also introduce the following five articles of this symposium

    A critical force constant of the structural phase transition in quartz

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    Long wavelength optical phonons of quartz were analyzed by a Born-Von Karman model not previously used. It was found that only one force constant associated with the turning of the Si-O bonds has a critical effect on the soft-mode frequency and the α-β transition in quartz. The square of the soft-mode frequency was found to depend linearly on this force constant which has the temperature dependence K(T)= -5.33+225.3x10-4(851-T)2/3 in units of 104 dyn/cm2

    Erosion patterns in a sediment layer

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    We report here on a laboratory-scale experiment which reproduces a rich variety of natural patterns with few control parameters. In particular, we focus on intriguing rhomboid structures often found on sandy shores and flats. We show that the standard views based on water surface waves come short to explain the phenomenon and we evidence a new mechanism based on a mud avalanche instability.Comment: 4 pages, 4 figures, to appear as Phys. Rev. E rapid com

    The Generalised LKF Transformations for Arbitrary NN-point Fermion Correlators

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    We examine the non-perturbative gauge dependence of arbitrary configuration space fermion correlators in quantum electrodynamics (QED). First, we study the dressed electron propagator (allowing for emission or absorption of any number of photons along a fermion line) using the first quantised approach to quantum field theory and analyse its gauge transformation properties induced by virtual photon exchange. This is then extended to the NN-point functions where we derive an exact, generalised version of the fully non-perturbative Landau-Khalatnikov-Fradkin (LKF) transformation for these correlators. We discuss some general aspects of application in perturbation theory and investigate the structure of the LKF factor about D=2D = 2 dimensions.Comment: 24 pages, 2 figure

    What did Aspiring Young Entrepreneurs in Nicaragua Recognize as Agribusiness and Ecotourism Opportunities using Photovoice as a Data Collection Tool?

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    Interest in entrepreneurship education by scholars and practitioners as a way to overcome poverty is growing. Yet little is known about how entrepreneurship can be a successful approach to achieving prosperity in resource-poor conditions. Entrepreneurship has been mainly associated with the view of entrepreneurs as super humans capable of solving all problems, especially if operating in resource-rich contexts. This qualitative study’s purpose was to explore, through photovoice methodology, the entrepreneurial opportunities involving agribusiness and ecotourism that Nicaraguan students recognized in their communities. Photovoice allowed the researchers to gain in-depth information from students who expressed in images what may have been difficult to explain in words. The students recognized different opportunities linked to their contexts as expressed through photos documenting local assets and materials. The study participants also indicated interests in doing social good, which suggested a more societally oriented view of entrepreneurship. The poor, including youth often marginalized, were able to recognize business opportunities in concert with their economic conditions. Opportunity recognition may be one of the more promising ways to overcome poverty. Its facilitation holds implications for agricultural, tourism, and rural development curricula and educational programming

    Generalized LKF transformations for NN-point fermion correlators in QED

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    Within the worldline approach to quantum electrodynamics (QED), a change of the photon's covariant gauge parameter Îľ\xi is investigated to analyse the non-perturbative gauge dependence of the configuration space fermion correlation functions, deriving a generalization of the Landau-Kalatnikov-Fradkin transformations (LKFt). These transformations reveal how the non-perturbative gauge dependence of position space amplitudes can be absorbed into a multiplicative exponential factor.Comment: Prepared for the Proceedings of the 20th Lomonosov Conference on Elementary Particle Physics, held in August 2021, based on a talk given by Jos\'e Nicasio on the results of arXiv:2012.10536 [hep-th] and arXiv:2010.04160 [hep-th

    What level of native beetle diversity can be supported by forestry plantations? A global synthesis

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    Forestry plantations have been established globally to meet timber demands, often leading to the conversion of natural to artificial forests. Forestry plantations may support natural elements of forest biodiversity, but understanding their role in the maintenance of biodiversity is a crucial question. We performed a meta-analysis of 48 studies to determine how forestry plantations relative to natural forests influence the species richness and abundance of three important coleopteran groups (i.e., ground beetles, rove beetles, and dung beetles), given their essential role in ecosystem functioning. We assessed whether beetle responses depended on taxonomic group, geographical location, native or exotic character of the planted tree species, and associated management characteristics (i.e., composition, size, age, and connectivity of the plantations). We found that forestry plantations negatively affected coleopteran species richness and abundance compared to natural forests. The negative impact was most severe in plantations with exotic tree species and located in tropical biomes. Species richness and abundance of beetles significantly increased with plantation age in native plantations but decreased in exotic ones. Also, small plantations close to native forest had higher beetle species richness and abundance than ones located far away from native forest. Stopping the conversion of natural forests to plantations, promoting the use of native tree species, and lengthening rotations are critical for allowing biodiversity recovery in forestry plantations, combined with a robust conservation strategy to protect threatened biodiversity and ecosystem functioning.Hungarian Basic Research FundRemedinalNatural Environment Research CouncilMinisterio de Ciencia e InnovaciĂł
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