3,190 research outputs found

    Will electricity deregulation push inflation lower?

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    Deregulation of electricity generation will offer consumers many advantages, including dramatically lower energy costs. From a macroeconomic viewpoint, electricity purchases are interesting because they are a major component of consumers’ budgets (and thus of the CPI) and a large factor of production for many companies. This raises the possibility that electricity deregulation could create a substantial shock to the overall price trend, comparable to other recent energy shocks. The benefits to consumers and producers identified in this article strongly support legislative efforts to increase competition in one of the last strongholds of regulated profits.Electric utilities ; Inflation (Finance)

    Active Brownian particles with velocity-alignment and active fluctuations

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    We consider a model of active Brownian particles with velocity-alignment in two spatial dimensions with passive and active fluctuations. Hereby, active fluctuations refers to purely non-equilibrium stochastic forces correlated with the heading of an individual active particle. In the simplest case studied here, they are assumed as independent stochastic forces parallel (speed noise) and perpendicular (angular noise) to the velocity of the particle. On the other hand, passive fluctuations are defined by a noise vector independent of the direction of motion of a particle, and may account for example for thermal fluctuations. We derive a macroscopic description of the active Brownian particle gas with velocity-alignment interaction. Hereby, we start from the individual based description in terms of stochastic differential equations (Langevin equations) and derive equations of motion for the coarse grained kinetic variables (density, velocity and temperature) via a moment expansion of the corresponding probability density function. We focus here in particular on the different impact of active and passive fluctuations on the onset of collective motion and show how active fluctuations in the active Brownian dynamics can change the phase-transition behaviour of the system. In particular, we show that active angular fluctuation lead to an earlier breakdown of collective motion and to emergence of a new bistable regime in the mean-field case.Comment: 5 figures, 22 pages, submitted to New Journal of Physic

    Promises and Lies: Restoring Violated Trust

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    Trust is critical for organizations, effective management, and efficient negotiations, yet trust violations are common. Prior work has often assumed trust to be fragile—easily broken and difficult to repair. We investigate this proposition in a laboratory study and find that trust harmed by untrustworthy behavior can be effectively restored when individuals observe a consistent series of trustworthy actions. Trust harmed by the same untrustworthy actions and deception, however, never fully recovers—even when deceived participants receive a promise, an apology, and observe a consistent series of trustworthy actions. We also find that a promise to change behaviour can significantly speed the trust recovery process, but prior deception harms the effectiveness of a promise in accelerating trust recovery

    Sustainable growth in complex networks

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    Based on the empirical analysis of the dependency network in 18 Java projects, we develop a novel model of network growth which considers both: an attachment mechanism and the addition of new nodes with a heterogeneous distribution of their initial degree, k0k_0. Empirically we find that the cumulative degree distributions of initial degrees and of the final network, follow power-law behaviors: P(k0)k01αP(k_{0}) \propto k_{0}^{1-\alpha}, and P(k)k1γP(k)\propto k^{1-\gamma}, respectively. For the total number of links as a function of the network size, we find empirically K(N)NβK(N)\propto N^{\beta}, where β\beta is (at the beginning of the network evolution) between 1.25 and 2, while converging to 1\sim 1 for large NN. This indicates a transition from a growth regime with increasing network density towards a sustainable regime, which revents a collapse because of ever increasing dependencies. Our theoretical framework is able to predict relations between the exponents α\alpha, β\beta, γ\gamma, which also link issues of software engineering and developer activity. These relations are verified by means of computer simulations and empirical investigations. They indicate that the growth of real Open Source Software networks occurs on the edge between two regimes, which are either dominated by the initial degree distribution of added nodes, or by the preferential attachment mechanism. Hence, the heterogeneous degree distribution of newly added nodes, found empirically, is essential to describe the laws of sustainable growth in networks.Comment: 5 pages, 2 figures, 1 tabl

    Risk-Seeking versus Risk-Avoiding Investments in Noisy Periodic Environments

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    We study the performance of various agent strategies in an artificial investment scenario. Agents are equipped with a budget, x(t)x(t), and at each time step invest a particular fraction, q(t)q(t), of their budget. The return on investment (RoI), r(t)r(t), is characterized by a periodic function with different types and levels of noise. Risk-avoiding agents choose their fraction q(t)q(t) proportional to the expected positive RoI, while risk-seeking agents always choose a maximum value qmaxq_{max} if they predict the RoI to be positive ("everything on red"). In addition to these different strategies, agents have different capabilities to predict the future r(t)r(t), dependent on their internal complexity. Here, we compare 'zero-intelligent' agents using technical analysis (such as moving least squares) with agents using reinforcement learning or genetic algorithms to predict r(t)r(t). The performance of agents is measured by their average budget growth after a certain number of time steps. We present results of extensive computer simulations, which show that, for our given artificial environment, (i) the risk-seeking strategy outperforms the risk-avoiding one, and (ii) the genetic algorithm was able to find this optimal strategy itself, and thus outperforms other prediction approaches considered.Comment: 27 pp. v2 with minor corrections. See http://www.sg.ethz.ch for more inf

    Analysis of Keck HIRES spectra of early L-type dwarfs

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    We present analyses of high resolution and medium resolution spectra of early L dwarfs. We used our latest set of model atmospheres to reproduce and analyze the observed features. We can model the optical flux and the atomic line profiles with the best accuracy to date. The models used to reproduce the observations include dust condensation and dust opacities. Compared to previous studies using older models we find that our dust treatment is much improved. The derived parameters for the objects are well in the expected range for old very low mass objects. This is also supported by the absence of Li in most of the objects. For the objects showing Li we can be almost certain that those are brown dwarfs. However, a spectral analysis in general, and this one in particular can only very roughly determine mass and age.Comment: AASTeX5.0. 26 pages, including all figures, Accepted for Ap

    Semiquantitative Assessment of Bowel Habits and Its Relation with Calcium Metabolism after Gastric Bypass Surgery: A Retrospective Study

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    Background. Calcium malabsorption after bariatric surgery may be harmful to skeletal health and demands for optimal skeletal management. Methods. 103 Patients were evaluated retrospectively at 12 months after surgery. The evaluation included a questionnaire about stool frequency and consistency and laboratory assessments. Results. 103 Patients, 27 males and 76 females, were included in the study. 83 Patients had an alimentary limb of 100 cm and 20 patients one of 150 cm. At 12 months after surgery, 77.7% reported changes of bowel habits, albumin adjusted calcium levels were normal in all but 2 patients, and PTH levels were increased in 35%. Correlations between semiquantified bowel scores (fecal scores) and data from the laboratory demonstrated increasing PTH values along with more frequent and softer/watery stools (RR 30.5, CI 6.2–149.2, P < .001). There was a trend for higher PTH levels in patients with an alimentary limb of 150 cm. Normal PTH levels were more frequently found in case of calcium and vitamin D3 use (RR 14.3, CI 3.6–56.5, P < .001). Conclusion. This study demonstrates interrelationships between semi-quantified fecal scores, PTH levels, and the compliance of taking calcium/vitamin D3 suppletion. However, prospective randomized studies are necessary to show causal relationships

    Critical generalized inverse participation ratio distributions

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    The system size dependence of the fluctuations in generalized inverse participation ratios (IPR's) Iα(q)I_{\alpha}(q) at criticality is investigated numerically. The variances of the IPR logarithms are found to be scale-invariant at the macroscopic limit. The finite size corrections to the variances decay algebraically with nontrivial exponents, which depend on the Hamiltonian symmetry and the dimensionality. The large-qq dependence of the asymptotic values of the variances behaves as q2q^2 according to theoretical estimates. These results ensure the self-averaging of the corresponding generalized dimensions.Comment: RevTex4, 5 pages, 4 .eps figures, to be published in Phys. Rev.

    Levitation of the quantum Hall extended states in the BB\to 0 limit

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    We investigate the fate of the quantum Hall extended states within a continuum model with spatially correlated disorder potentials. The model can be projected onto a couple of the lowest Landau bands. Levitation of the n=0n=0 critical states is observed if at least the two lowest Landau bands are considered. The dependence on the magnetic length lB=(/(eB))1/2l_B=(\hbar/(eB))^{1/2} and on the correlation length of the disorder potential η\eta is combined into a single dimensionless parameter η^=η/lB\hat\eta=\eta/l_B. This enables us to study the behavior of the critical states for vanishing magnetic field. In the two Landau band limit, we find a disorder dependent saturation of the critical states' levitation which is in contrast to earlier propositions, but in accord with some experiments.Comment: 7 pages, 9 figures. Replaced with published versio
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