330 research outputs found

    The complex effects of the invasive polychaetes Marenzelleria spp. on benthic nutrient dynamics

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    The effects of the polychaetes Marenzelleria sp. (Polychaeta, Spionidae), nonindigenous, rapidly increasing species in the Baltic Sea, on benthic nutrient fluxes, denitrification and sediment pore water nutrient concentration were studied in laboratory experiments using a flow-through setup with muddy sediment from coastal regions of the Gulf of Finland. In addition, different forms of sediment phosphorus (P), separated by chemical fractionation, were studied in three sediment layers. At a population density corresponding to about half the highest measured in the northern Baltic Sea, Marenzelleria sp. increased the fluxes of P and ammonium to the water column. No effect could be recorded for denitrification. Since the previously dominant species of the area, Monoporeia affinis, can enhance denitrification and lower the amount of dissolved P in the pore water, the replacement of M affinis with Marenzelleria spp. may lead to increased P flux to the water column and decreased denitrification, further increasing the ammonium flux to the water column. However, sediment reworking by Marenzelleria spp. also oxidizes the surface sediment in the long run, improving its ability to retain P and support nitrification. Therefore, the impact of Marenzelleria spp. on sediment nutrient release may not be as drastic as the initial reactions seen in our experiments suggest. (c) 2007 Elsevier B.V. All rights reserved.The effects of the polychaetes Marenzelleria sp. (Polychaeta, Spionidae), nonindigenous, rapidly increasing species in the Baltic Sea, on benthic nutrient fluxes, denitrification and sediment pore water nutrient concentration were studied in laboratory experiments using a flow-through setup with muddy sediment from coastal regions of the Gulf of Finland. In addition, different forms of sediment phosphorus (P), separated by chemical fractionation, were studied in three sediment layers. At a population density corresponding to about half the highest measured in the northern Baltic Sea, Marenzelleria sp. increased the fluxes of P and ammonium to the water column. No effect could be recorded for denitrification. Since the previously dominant species of the area, Monoporeia affinis, can enhance denitrification and lower the amount of dissolved P in the pore water, the replacement of M affinis with Marenzelleria spp. may lead to increased P flux to the water column and decreased denitrification, further increasing the ammonium flux to the water column. However, sediment reworking by Marenzelleria spp. also oxidizes the surface sediment in the long run, improving its ability to retain P and support nitrification. Therefore, the impact of Marenzelleria spp. on sediment nutrient release may not be as drastic as the initial reactions seen in our experiments suggest. (c) 2007 Elsevier B.V. All rights reserved.The effects of the polychaetes Marenzelleria sp. (Polychaeta, Spionidae), nonindigenous, rapidly increasing species in the Baltic Sea, on benthic nutrient fluxes, denitrification and sediment pore water nutrient concentration were studied in laboratory experiments using a flow-through setup with muddy sediment from coastal regions of the Gulf of Finland. In addition, different forms of sediment phosphorus (P), separated by chemical fractionation, were studied in three sediment layers. At a population density corresponding to about half the highest measured in the northern Baltic Sea, Marenzelleria sp. increased the fluxes of P and ammonium to the water column. No effect could be recorded for denitrification. Since the previously dominant species of the area, Monoporeia affinis, can enhance denitrification and lower the amount of dissolved P in the pore water, the replacement of M affinis with Marenzelleria spp. may lead to increased P flux to the water column and decreased denitrification, further increasing the ammonium flux to the water column. However, sediment reworking by Marenzelleria spp. also oxidizes the surface sediment in the long run, improving its ability to retain P and support nitrification. Therefore, the impact of Marenzelleria spp. on sediment nutrient release may not be as drastic as the initial reactions seen in our experiments suggest. (c) 2007 Elsevier B.V. All rights reserved.Peer reviewe

    Pressure to order g8∗log(g)g^8*log(g) in ϕ4\phi^4-theory at weak coupling

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    We calculate the pressure of massless ϕ4\phi^4-theory to order g8log⁥(g)g^8\log(g) at weak coupling. The contributions to the pressure arise from the hard momentum scale of order TT and the soft momentum scale of order gTgT. Effective field theory methods and dimensional reduction are used to separate the contributions from the two momentum scales: The hard contribution can be calculated as a power series in g2g^2 using naive perturbation theory with bare propagators. The soft contribution can be calculated using an effective theory in three dimensions, whose coefficients are power series in g2g^2. This contribution is a power series in gg starting at order g3g^3. The calculation of the hard part to order g6g^6 involves a complicated four-loop sum-integral that was recently calculated by Gynther, Laine, Schr\"oder, Torrero, and Vuorinen. The calculation of the soft part requires calculating the mass parameter in the effective theory to order g6g^6 and the evaluation of five-loop vacuum diagrams in three dimensions. This gives the free energy correct up to order g7g^7. The coefficients of the effective theory satisfy a set of renormalization group equations that can be used to sum up leading and subleading logarithms of T/gTT/gT. We use the solutions to these equations to obtain a result for the free energy which is correct to order g8log⁥(g)g^8\log(g). Finally, we investigate the convergence of the perturbative series.Comment: 29 pages and 12 figs. New version: we have pushed the calculations to g^8*log(g) using the renormalization group to sum up log(g) from higher orders. Published in JHE

    Perception of eye contact, self-referential thinking and age

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    Increased thinking about one's self has been proposed to widen the gaze cone, that is, the range of gaze deviations that an observer judges as looking directly at them (eye contact). This study investigated the effects of a self-referential thinking manipulation and demographic factors on the gaze cone. In a preregistered experiment (N = 200), the self-referential thinking manipulation, as compared to a control manipulation, did not influence the gaze cone, or the use of first-person pronouns in a manipulation check measuring self-referential processing. This may indicate a failure of the manipulation and participants’ lack of effort. However, participants’ age was significantly correlated with both measures: older people had wider gaze cones and used more self-referring pronouns. A second experiment (N = 300) further examined the effect of the manipulation and demographic factors on self-referential processing, and the results were replicated. These findings may reflect age-related self-reference and positivity effects.publishedVersionPeer reviewe

    Epistemology and public policy : Using a new typology to analyse the paradigm shift in Finnish transport futures research

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    The aim of the article is to present a new typology of paradigms of futures studies with specific focus on decision-making. Possible roles of futurists and other actors in long-term planning and decision-making processes are formed using logical analysis. The resulting seven schools of thought are interpreted in the light of literature of futures studies and planning theory. Connections to the philosophical discussion on the role of knowledge and values in policy recommendations are presented as well. Some futures studies methodological applications are attached to the paradigms. The new typology forms a gradient from technocracy performed by professionals to direct citizen participation. Finally, the paradigm shift of Finnish national transport futures studies is analysed using the new typology

    Constraints on Conformal Windows from Holographic Duals

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    We analyze a beta function with the analytic form of Novikov-Shifman-Vainshtein-Zakharov result in the five dimensional gravity-dilaton environment. We show how dilaton inherits poles and fixed points of such beta function through the zeros and points of extremum in its potential. Super Yang-Mills and supersymmetric QCD are studied in detail and Seiberg's electric-magnetic duality in the dilaton potential is explicitly demonstrated. Non-supersymmetric proposals of similar functional form are tested and new insights into the conformal window as well as determinations of scheme-independent value of the anomalous dimension at the fixed point are presented.Comment: Fig. 5b is corrected to match the discussion in the tex

    BIM data model requirements for asset monitoring and the circular economy

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    © 2020, Emerald Publishing Limited. Purpose: The purpose of this paper is to review and provide recommendations to extend the current open standard data models for describing monitoring systems and circular economy precepts for built assets. Open standard data models enable robust and efficient data exchange which underpins the successful implementation of a circular economy. One of the largest opportunities to reduce the total life cycle cost of a built asset is to use the building information modelling (BIM) approach during the operational phase because it represents the largest share of the entire cost. BIM models that represent the actual conditions and performance of the constructed assets can boost the benefits of the installed monitoring systems and reduce maintenance and operational costs. Design/methodology/approach: This paper presents a horizontal investigation of current BIM data models and their use for describing circular economy principles and performance monitoring of built assets. Based on the investigation, an extension to the industry foundation classes (IFC) specification, recommendations and guidelines are presented which enable to describe circular economy principles and asset monitoring using IFC. Findings: Current open BIM data models are not sufficiently mature yet. This limits the interoperability of the BIM approach and the implementation of circular economy principles. An overarching approach to extend the current standards is necessary, which considers aspects related to not only modelling the monitoring system but also data management and analysis. Originality/value: To the authors’ best knowledge, this is the first study that identifies requirements for data model standards in the context current linear economic model of making, using and disposing is growing unsustainably far beyond the finite limits of planet of a circular economy. The results of this study set the basis for the extension of current standards required to apply the circular economy precepts

    Superweakly interacting dark matter from the Minimal Walking Technicolor

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    We study a superweakly interacting dark matter particle motivated by minimal walking technicolor theories. Our WIMP is a mixture of a sterile state and a state with the charges of a standard model fourth family neutrino. We show that the model can give the right amount of dark matter over a range of the WIMP mass and mixing angle. We compute bounds on the model parameters from the current accelerator data including the oblique corrections to the precision electroweak parameters, as well as from cryogenic experiments, Super-Kamiokande and from the IceCube experiment. We show that consistent dark matter solutions exist which satisfy all current constraints. However, almost the entire parameter range of the model lies within the the combined reach of the next generation experiments.Comment: 29 pages, 6 figure

    Treatment of keloid scars with intralesional triamcinolone and 5-fluorouracil injections - a randomized controlled trial

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    Keloids have high recurrence rates. Current first-line therapy is triamcinolone (TAC) injection, but it has been suggested that approximately 50% of keloids are steroid resistant. We compared the efficacy of intralesional 5-fluorouracil (5-FU) and triamcinalone injections in a double-blind randomized controlled trial. Forty-three patients with 50 keloid scars were treated with either intralesional TAC or 5-FU-injections over 6 months. There was no statistically significant difference in the remission rate at 6 months between the 5-FU and TAC groups (46% vs 60%, respectively). Local adverse effects were higher in the TAC group compared to the 5-FU group. Occurrence of skin atrophy in TAC group was 44% and in the 5-FU group 8% (p <0.05). Also the occurrence of telangiectasia in the TAC group was 50% and in the 5-FU 21% (p <0.05). Vascularity of the keloids, assessed by spectral imaging and immunohistochemical staining for blood vessels, after treatment decreased in the TAC group, but not in the 5-FU group (p <0.05). Fibroblast proliferation evaluated by Ki-67 staining significantly decreased in the TAC group (p <0.05) but increased in the 5-FU group (p <0.05). TAC and 5-FU injections did not differ in their clinical effectivity in this randomized study, but 5-FU injections lead to increased proliferation rate and did not affect vascular density in histological assessment. Due to the greater number of adverse effects observed after TAC treatment, 5-FU injections may be preferable for cosmetically sensitive skin areas. (C) 2018 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.Peer reviewe
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