1,017 research outputs found
Probing nonlinear adiabatic paths with a universal integrator
We apply a flexible numerical integrator to the simulation of adiabatic
quantum computation with nonlinear paths. We find that a nonlinear path may
significantly improve the performance of adiabatic algorithms versus the
conventional straight-line interpolations. The employed integrator is suitable
for solving the time-dependent Schr\"odinger equation for any qubit
Hamiltonian. Its flexible storage format significantly reduces cost for storage
and matrix-vector multiplication in comparison to common sparse matrix schemes.Comment: 8 pages, 6 figure
The Mass of Dwarf Planet Eris
The discovery of dwarf planet Eris was followed shortly by the discovery of its satellite, Dysnomia, but the satellite orbit, and thus the system mass, was not known. New observations with the Keck Observatory and the Hubble Space Telescopes show that Dysnomia has a circular orbit with a radius of 37,350 ± 140 (1-σ) kilometers and a 15.774 ± 0.002 day orbital period around Eris. These orbital parameters agree with expectations for a satellite formed out of the orbiting debris left from a giant impact. The mass of Eris from these orbital parameters is 1.67 × 10^(22) ± 0.02 × 10^(22) kilograms, or 1.27 ± 0.02 that of Pluto
The East German Cement Cartel : An Inquiry into Comparable Markets, Industry Structure, and Antitrust Policy
Maintaining sufficient levels of competition ranks among the core interests of any national – and increasingly international – antitrust policy; however, the formal proof that a cartel really functioned economically and did not only exist in a legal sense is hard to deliver: market power is not identical to the existence of a legal cartel unless the monopolistic frontier is reached; the legal proof of a cartel does not imply that the market was harmed. From an economic point of view, focusing on legal proof of a cartel is fruitless unless collusion resulted in excess profits or excess revenues. This economic evidence, however, rests empirically on the proper definition of comparable markets, and a sound statistical methodology. When in spring 2003, the German Antitrust Agency (GAA) fined the German cement industry – € 661 million for having established quotas in each of the four market regions through the end of 2001, the legal issue seemed beyond doubt as, beside formal inquiries, two of the industry members had acted as key witnesses. However, the economic implications drawn by the GAA remain doubtful. In this paper, we use the quota agreement in the East German market, the region for which these allegations are undisputed by all major suppliers, as a reference case. We challenge the GAA’s computation of excess income of 10 €/ton on two grounds: (i), the comparative market period chosen, 2002, does not meet the requirements of a reference market, especially regarding a certain level of stability and converging prices; (ii) three parallel developments could have triggered the price decline: the openly announced end of the quota cartel, which generated general price-setting insecurity (ii-a), the price war triggered by one of the oligopolists, who desperately tried to improve poor utilization of capacity and squeeze out competitors (ii-b), and the general decline in construction activity (ii-c). Within the framework of an econometric model based on data of one German cement producer, we find that sufficient levels of competition prevailed throughout the cartel period. Furthermore, the demand structure did not change from 2001 to 2002 so as to suggest a fundamental change in competition. Finally, no excess income or profit can be computed. In fact, we show that the general demand regime estimated for the period 1995 to 2001, which is the period of alleged market power, equally well describes the market condition of 2002. Price war and a collapsing construction market lead suppliers to maintain levels of production and capacity utilization, thus sacrificing profits at the expense of the market shares of small and medium-sized suppliers independently from the cartel issue. This empirical finding of an agreed but ineffective cartel is supported by theoretical evidence on the conditions under which cartels can work effectively – which did not exist in the East: strong import competition, a high level of transparency limiting the effects of „cheap talk“ and spatial pricing that generates local market power in the absence of cartels. Furthermore, general supply-side conditions in the cement industry suggest that a considerable level of imperfect competition is structurally unavoidable; antitrust possibilities that in the short run enforce additional competition based on the wrong assessment of effective collusion may lead to exits and less competition in the long run. We conclude that the methodology described may be useful for antitrust policy as it offers a credible analytical tool to compute excess income and profit. --antitrust,cement,competition,collusion,Germany,econometrics,excess income,excess profit,quota agreement
FAK and paxillin: regulators of N-cadherin adhesion and inhibitors of cell migration?
FAK and paxillin are important components in integrin-regulated signaling. New evidence suggests that these two proteins function in crosstalk between cell–matrix and cell–cell adhesions. Further, new insight suggests that under some conditions these proteins inhibit cell migration, in contrast to their established roles in several cell systems as positive regulators of cell adhesion and migration
Energiesparberatung im Kiez : Evaluation des Projektes clevererKIEZ e.V.
In Deutschland haben einige Millionen Haushalte Schwierigkeiten, ihre Energierechnung zu bezahlen. Ein Lösungsansatz liegt in der Energieberatung. Das Projekt clevererKIEZ basierte auf einem integrativen Konzept, welches arbeitsmarkt- sowie sozial- und umweltpolitische Ziele miteinander verknüpft. Im Rahmen einer intensiven Schulungsmaßnahme qualifizierten sich Langzeitarbeitslose zu Energieberatern. Zwischen 2010 und 2013 nahmen über 1000 Haushalte am Projekt teil. Der Bericht stellt das Projekt vor und erläutert die Ergebnisse der summativen Evaluation. Im Mittelpunkt stehen die Schwerpunktbereiche: 1. Nutzeranalyse der am Projekt teilnehmenden Haushalte, 2. Analyse des Energieverbrauches sowie der Einsparerfolge, 3. Feedback der eingesetzten Energiesparberater und 4. Auswertung der Öffentlichkeitsarbeit
Overview of the coordinated ground-based observations of Titan during the Huygens mission
Coordinated ground-based observations of Titan were performed around or during the Huygens atmospheric probe mission at Titan on 14 January 2005, connecting the momentary in situ observations by the probe with the synoptic coverage provided by continuing ground-based programs. These observations consisted of three different categories: (1) radio telescope tracking of the Huygens signal at 2040 MHz, (2) observations of the atmosphere and surface of Titan, and (3) attempts to observe radiation emitted during the Huygens Probe entry into Titan's atmosphere. The Probe radio signal was successfully acquired by a network of terrestrial telescopes, recovering a vertical profile of wind speed in Titan's atmosphere from 140 km altitude down to the surface. Ground-based observations brought new information on atmosphere and surface properties of the largest Saturnian moon. No positive detection of phenomena associated with the Probe entry was reported. This paper reviews all these measurements and highlights the achieved results. The ground-based observations, both radio and optical, are of fundamental importance for the interpretation of results from the Huygens mission
Modeling cultural change: computational models of interpersonal influence dynamics can yield new insights about how cultures change, which cultures change more rapidly than others, and why
Cultural change can occur as an emergent consequence of social influence dynamics within cultural populations. These influence dynamics are complex, and formal modeling methods-such as agent-based models-are a useful means of predicting implications for cultural change. These models may be especially useful if they not only model the psychological outcomes of interpersonal influence, but also model social network structures within a culture. When combined, these components provide a flexible modeling framework that allows other variables to also be modeled for the purposes of predicting plausible implications for cultural change. The article illustrates this approach by summarizing recent research that used these methods to model cross-cultural differences in the pace of cultural change. The article then identifies additional variables that could potentially be modeled within this conceptual framework, to produce additional insights-and additional new hypotheses-about different circumstances associated with different patterns of cultural change
The Surface of 2003 EL_(61) in the Near-Infrared
We report the detection of crystalline water ice on the surface of 2003 EL_(61). Reflectance spectra were collected from the Gemini North telescope in the 1.0 to 2.4 μm wavelength range and from the Keck telescope across the 1.4-2.4 μm wavelength range. The signature of crystalline water ice is obvious in all data collected. Like the surfaces of many outer solar system bodies, the surface of 2003 EL_(61) is rich in crystalline water ice, which is energetically less favored than amorphous water ice at low temperatures, suggesting that resurfacing processes may be taking place. The near-infrared color of the object is much bluer than a pure water ice model. Adding a near-infrared blue component such as hydrogen cyanide or phyllosilicate clays improves the fit considerably, with hydrogen cyanide providing the greatest improvement. The addition of hydrated tholins and bitumens also improves the fit, but is inconsistent with the neutral V - J reflectance of 2003 EL_(61). A small decrease in reflectance beyond 2.3 μm may be attributable to cyanide salts. Overall, the reflected light from 2003 EL_(61) is best fit by a model of 2/3-4/5 pure crystalline water ice and 1/3-1/5 near-infrared blue component such as hydrogen cyanide or kaolinite. The surface of 2003 EL_(61) is unlikely to be covered by significant amounts of dark material such as carbon black, as our pure ice models reproduce published albedo estimates derived from the spin state of 2003 EL_(61)
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