7,231 research outputs found

    Patent collateral, investor commitment, and the market for venture lending

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    This paper investigates the market for lending to technology startups (i.e., venture lending) and examines two mechanisms that may facilitate trade within it: (1) the ‘salability’ of patent collateral; and (2) the credible commitment of existing equity investors. We find that intensified trading in the secondary patent market is strongly related to the annual rate of startup lending, particularly for startups with more redeployable patent assets. Moreover, we show that the credibility of venture capitalist commitments to reinvest in their startups’ next round of financing can be critical for startup debt provision. Utilizing the crash of 2000 as a severe and unexpected capital supply shock for VCs, we show that lenders continue to finance startups with recently funded investors better able to credibly commit to refinance their portfolio companies, but withdraw from otherwise-promising projects that may have needed their funds the most. The findings are consistent with predictions of incomplete contracting and financial intermediation theory.Accepted manuscrip

    Short-range order and precipitation in Fe-rich Fe-Cr alloys: Atomistic off-lattice Monte Carlo simulations

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    Short-range order (SRO) in Fe-rich Fe-Cr alloys is investigated by means of atomistic off-lattice Monte Carlo simulations in the semi-grand canonical ensemble using classical interatomic potentials. The SRO parameter defined by Cowley [Phys. Rev. B 77, 669 (1950)] is used to quantify the degree of ordering. In agreement with experiments a strong ordering tendency in the Cr distribution at low Cr concentrations (~< 5%) is observed, as manifested in negative values of the SRO parameters. For intermediate Cr concentrations (5% ~< c_Cr ~< 15%) the SRO parameter for the alpha-phase goes through a minimum, but at the solubility limit the alpha-phase still displays a rather strong SRO. In thermodynamic equilibrium for concentrations within the two-phase region the SRO parameter measured over the entire sample therefore comprises the contributions from both the alpha and alpha-prime phases. If both of these contributions are taken into account, it is possible to quantitatively reproduce the experimental results and interpret their physical implications. It is thereby shown that the inversion of the SRO observed experimentally is due to the formation of stable (supercritical) alpha-prime precipitates. It is not related to the loss of SRO in the alpha-phase or to the presence of unstable (subcritical) Cr precipitates in the alpha-phase.Comment: 9 pages, 8 figure

    Simultaneous Surface Plasmon Resonance and X-ray Absorption Spectroscopy

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    We present here an experimental set-up to perform simultaneously measurements of surface plasmon resonance (SPR) and X-ray absorption spectroscopy (XAS) in a synchrotron beamline. The system allows measuring in situ and in real time the effect of X-ray irradiation on the SPR curves to explore the interaction of X-rays with matter. It is also possible to record XAS spectra while exciting SPR in order to detect the changes in the electronic configuration of thin films induced by the excitation of surface plasmons. Combined experiments recording simultaneously SPR and XAS curves while scanning different parameters can be carried out. The relative variations in the SPR and XAS spectra that can be detected with this set-up ranges from 10-3 to 10-5, depending on the particular experiment

    Thermodynamically admissible form for discrete hydrodynamics

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    We construct a discrete model of fluid particles according to the GENERIC formalism. The model has the form of Smoothed Particle Hydrodynamics including correct thermal fluctuations. A slight variation of the model reproduces the Dissipative Particle Dynamics model with any desired thermodynamic behavior. The resulting algorithm has the following properties: mass, momentum and energy are conserved, entropy is a non-decreasing function of time and the thermal fluctuations produce the correct Einstein distribution function at equilibrium.Comment: 4 page

    Yard-Sale exchange on networks: Wealth sharing and wealth appropriation

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    Yard-Sale (YS) is a stochastic multiplicative wealth-exchange model with two phases: a stable one where wealth is shared, and an unstable one where wealth condenses onto one agent. YS is here studied numerically on 1d rings, 2d square lattices, and random graphs with variable average coordination, comparing its properties with those in mean field (MF). Equilibrium properties in the stable phase are almost unaffected by the introduction of a network. Measurement of decorrelation times in the stable phase allow us to determine the critical interface with very good precision, and it turns out to be the same, for all networks analyzed, as the one that can be analytically derived in MF. In the unstable phase, on the other hand, dynamical as well as asymptotic properties are strongly network-dependent. Wealth no longer condenses on a single agent, as in MF, but onto an extensive set of agents, the properties of which depend on the network. Connections with previous studies of coalescence of immobile reactants are discussed, and their analytic predictions are successfully compared with our numerical results.Comment: 10 pages, 7 figures. Submitted to JSTA

    Serial Changes in Plasma Levels of Cytokines in Patients with Coronary Artery Disease

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    Roberto H Heinisch1, Carlos R Zanetti1, Fabiano Comin1, Juliano L Fernandes2, Jos&eacute; A Ramires2, Carlos V Serrano Jr21Federal University of Santa Catarina, Florian&oacute;polis, Brazil; 2Heart Institute (InCor), University of S&atilde;o Paulo Medical School, S&atilde;o Paulo, BrazilObjectives: Inflammation is known to be a major determinant of the progression of coronary artery disease (CAD). In the present study we have evaluated the plasma levels of cytokines &ndash; tumor necrosis factor-&alpha; (TNF), interleukin-1&alpha; (IL-1), interleukin-6 (IL-6), interferon-&gamma; (IFN), and interleukin-10 (IL-10) &ndash; to examine the association between these cytokines and C-reactive protein (CRP) in patients with CAD.Methods: Patients with acute coronary syndromes (ACS; n = 20) were compared with patients with stable angina (SA; n = 20) and with control volunteers (C; n = 20). Blood samples were collected at the time of admission from all patients and 15 and 30 days thereafter.Results: CRP levels (20.8 &plusmn; 8.8 mg/L) (mean &plusmn; SEM) were higher at baseline in ACS than SA patients (4.1 &plusmn; 0.8 mg/L) or the control subjects (5.1 &plusmn; 1.8 mg/L) (p &lt; 0.05). At admission, IL-6 was detected in 50% of the ACS patients and 5% of the SA patients or control subjects, while TNF was detected in 35% of the ACS and SA patients but only in 5% of control subjects. Subsequently, IL-6 levels declined and were no longer detectable, while TNF levels increased among ACS patients at all time periods tested when compared with other patients. The presence of IL-1 and IL-10 were not detectable in the blood samples examined, and IFN could only be detected in the ACS group. A significant correlation was observed between IL-6 and CRP levels (r = 0.4; p &lt; 0.01) in all groups. There were no correlations among any of the other cytokines and CRP levels.Conclusions: Our study demonstrates raised levels of TNF, IL6, IFN, and CRP in patients with ACS and a positive correlation between IL6 and CRP but not with the other cytokines. Keywords: cytokines, tumor necrosis factor-&alpha;, interleukin-6, C-reactive protein, coronary artery diseas

    Electron-phonon renormalization of the absorption edge of the cuprous halides

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    Compared to most tetrahedral semiconductors, the temperature dependence of the absorption edges of the cuprous halides (CuCl, CuBr, CuI) is very small. CuCl and CuBr show a small increase of the gap E0E_0 with increasing temperature, with a change in the slope of E0E_0 vs. TT at around 150 K: above this temperature, the variation of E0E_0 with TT becomes even smaller. This unusual behavior has been clarified for CuCl by measurements of the low temperature gap vs. the isotopic masses of both constituents, yielding an anomalous negative shift with increasing copper mass. Here we report the isotope effects of Cu and Br on the gap of CuBr, and that of Cu on the gap of CuI. The measured isotope effects allow us to understand the corresponding temperature dependences, which we also report, to our knowledge for the first time, in the case of CuI. These results enable us to develop a more quantitative understanding of the phenomena mentioned for the three halides, and to interpret other anomalies reported for the temperature dependence of the absorption gap in copper and silver chalcogenides; similarities to the behavior observed for the copper chalcopyrites are also pointed out.Comment: 14 pages, 5 figures, submitted to Phys. Rev.

    IUmote: A Framework for the Efficient Modelling, Evaluation, and Deployment of Algorithms and Hardware for Underwater Communications

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    We present an approach for the modelling and simulating of the modem section of underwater sensor networks. The proposal is based on a specially designed modem architecture and the use of simulation tools and models that represent each of the communication elements: the water medium, physical transducers, electronics, and coding/decoding software. The algorithms can be simulated in the modelling environment; this framework does not require recoding and allows the combination of real and modelled elements. In physical terms, the modem engine provides a decoupled pipelined design of the processing path for the algorithms which allows users to run complex algorithms without requiring a highly demanding specific hardware. The proposal includes a methodology that has allowed us to significantly reduce the effort required in the process, from algorithm development to the effective deployment of the system. As a case study, this paper shows its application and results in the evaluation of a multipath and Doppler-shift correction algorithms.The authors gratefully acknowledge financial support from the CICYT ANDREA: Automated Inspection and Remote Performance of Marine Fish Farms (CTM2011-29691-C02-01), RIDeWAM: Research on Improvement of the Dependability of WSN based Applications by developing a hybrid monitoring platform (TIN2011-28435-C03-01), Valencian Regional Government under Research Project GV/2014/012, and Universitat Politecnica de Valencia under Research Project UPV PAID-02-12. The translation of this paper was funded by the Universitat Politecnica de Valencia, Spain.Sánchez Matías, AM.; Perles Ivars, A.; Yuste Pérez, P.; Capella Hernández, JV.; Serrano Martín, JJ. (2015). IUmote: A Framework for the Efficient Modelling, Evaluation, and Deployment of Algorithms and Hardware for Underwater Communications. International Journal of Distributed Sensor Networks. 2015:1-14. https://doi.org/10.1155/2015/358315S114201
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