377 research outputs found

    Crowdfunding revisited: a neo-institutional field-perspective

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    Crowdfunding, which relies on the aggregated financial power of the many non-institutionalised individuals, who pledge small amounts is seen in the literature as a particularly well-suited form of entrepreneurial finance. A reason for this may be that the investment decisions are more based on the value propositions of a venture than on purely financial factors. Yet, the communication and translation of the value propositions of a venture into various cultural and regulatory contexts requires specialised services and joint efforts. These services are enabled by so-called Crowdfunding Platforms (CFPs) which provide the necessary tools and services. However, they also influence and potentially limit the field through their actions. Applying an institutional field-perspective in order to gain more holistic insights on the interplay between structure and agents, we revise the originally proposed model developed in our 2013 article in Venture Capital based on an extensive update of the literature and provide new insights from additional empirical cases to triangulate the recent scholarly contributions. We finally enhance theory on crowdfunding on an institutional field-level with a better conceptualization of the interconnectedness between actors and their activities, as well as their positions and links within the structure and crowdfunding platforms as powerful central actors

    Dependence on plasma shape and plasma fueling for small edge-localized mode regimes in TCV and ASDEX Upgrade

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    Within the EUROfusion MST1 work package, a series of experiments has been conducted on AUG and TCV devices to disentangle the role of plasma fueling and plasma shape for the onset of small ELM regimes. On both devices, small ELM regimes with high confinement are achieved if and only if two conditions are fulfilled at the same time. Firstly, the plasma density at the separatrix must be large enough (n e,sep/n G ∼ 0.3), leading to a pressure profile flattening at the separatrix, which stabilizes type-I ELMs. Secondly, the magnetic configuration has to be close to a double null (DN), leading to a reduction of the magnetic shear in the extreme vicinity of the separatrix. As a consequence, its stabilizing effect on ballooning modes is weakened

    Quality of life after aortic valve repair is similar to Ross patients and superior to mechanical valve replacement: A cross-sectional study

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    Background: In patients after aortic valve surgery, the quality of life is hypothesized to be influenced by the type of the valve procedure. A cross-sectional study on the postoperative quality of life was carried out in patients after aortic valve-sparing surgery (with regards to the age of the patient), Ross procedure and mechanical aortic valve replacement. Methods: Quality of life was studied in 139 patients after aortic valve surgery divided into four study groups (Y - aortic valve-sparing procedure at the age below 50years, mean age 36.2years; O - aortic valve-sparing procedure at the age 50years and over, mean age 59.2years; R - Ross procedure, mean age 37.8years and M - mechanical aortic valve replacement at the age below 50years, mean age 39.2years). SF-36 Short Form and valve-specific questionnaires were mailed to the patients after 6months or later following surgery (median 26.9months). Results: In SF-36, the younger aortic valve repair patients and the Ross patients scored significantly better in 4 of 4 physical subscales and in 2 of 4 mental subscales than the older aortic valve repair and mechanical valve replacement patients. In the valve-specific questionnaire; however, all 3 groups free of anticoagulation (Y, O, and R) displayed greater freedom from negative valve-related concerns. Conclusions: Postoperative quality of life is influenced by the type of aortic valve procedure and is negatively linked with mechanical prosthesis implantation and long-term anticoagulation. Aortic valve-sparing strategy should be considered in cases with suitable valve morphology due to favorable clinical results and beneficial impact on the long-term quality of life

    HIV Activates the Tyrosine Kinase Hck to Secrete ADAM Protease-Containing Extracellular Vesicles

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    HIV-Nef activates the myeloid cell-typical tyrosine kinase Hck, but its molecular role in the viral life cycle is not entirely understood. We found that HIV plasma extracellular vesicles (HIV pEV) containing/10 proteases and Nef also harbor Hck, and analyzed its role in the context of HIV pEV secretion. Myeloid cells required Hck for the vesicle-associated release of ADAM17. This could be induced by the introduction of Nef and implied that HIV targeted Hck for vesicle-associated ADAM17 secretion from a myeloid compartment. The other contents of HIV-pEV, however, including miRNA and effector protein profiles, as well as the presence of haptoglobin suggested hepatocytes as a possible cellular source. HIV liver tissue analysis supported this assumption, revealing induction of Hck translation, evidence for ADAMprotease activation and HIV infection. Our findings suggest that HIV targets Hck to induce pro-inflammatory vesicles release and identifies hepatocytes as a possible host cell compartment. (c) 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.Peer reviewe

    Effect of different contact formulations used in commercial FEM software packages on the results of hot forging simulations

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    Commercial FEM-software packages are widely used in the industry to predict material flow, temperaturedistribution and die load during the forging process. Contact in conjunction with plastic material behaviour,which is typical for forging simulations, leads to highly nonlinear equations in the FEM algorithms, whichmay cause problems in numerical convergence. Some FEM software providers handle this problem byautomatic contact damping or similar algorithms. However, the user has mostly no detailed information aboutadjustments and prediction accuracy. The only possibility for the user to have an impact on the contactbehaviour is to set a friction factor and to choose a friction model (e.g. Coloumb or Shear) appropriate to theinvestigated process. Friction factors are often measured by standard tests like the ring compression test whichshould be valid for all used software packages. In this paper a benchmark between three software programs isperformed based on a model for ring compression tests under typical hot forging conditions. The commercialFEM-software programs Deform2D, Forge2007 and Abaqus are compared by generating a nomogram for eachsoftware package. For all simulations identical physical (temperature, flow curves etc.) as well as numericalinfluence parameters are used. The simulations show a significant divergence in the results depending on theused FEM-software. This leads to the conclusion that a friction coefficient which is true for one softwarepackage can not be transferred directly into another one
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