The cosmic dust analyzer: Experimental evaluation of an impact ionization model

A thermal equilibrium plasma model is used to process data from an impact ionization time-of-flight mass spectrometer in order to convert the raw ion data to relative abundances of the elemental constituents of cosmic dust particles

Towards functional safety in automotive electronics

International audienceThe part of electronics in automobile design becomes more and more important with an exponential growth during the last 10 years. Nowadays, innovation in automotive industry is driven by electronics. New upcoming electrical/electronic systems (E/E systems) such as advanced driver assistance systems or x-by-wire systems as well as consumer expectation regarding safety will require a dedicated standard to ensure design, development and production of safe products before their introduction on the market.ISO/TC22/SC3/WG16 has been formed to issue the ISO26262 international standard that will specifically address functional safety of E/E systems of automotive industry.This paper provides information about the future ISO26262 which is based on the current results of ISO/TC22/SC3/WG16 [1], those still being subject to changes before the international standard release

Two component X-ray emission from RS CVn binaries

A summary of results from the solid state spectrometer on the Einstein Observatory for 7 RS CVn binaries is presented. The spectra of all require two emission components, evidenced by line emission characteristic of plasma at 4 to 8 x 10 to the 6th power and bremsstrahlung characteristic of 20 to 100 x 10 to the 6th power K. The data are interpreted in terms of magnetic coronal loops similar to those seen on the Sun, although with different characteristic parameters. The emission regions could be defined by separate magnetic structures. For pressure less than approximately 10 dynes/sq cm the low temperature plasma would be confined within the stellar radii, while the high temperature plasma would, for the synchronous close binaries, fill the binary orbits. However, for loop pressures exceeding 100 dynes/sq cm, the high temperature components would also be confined to within the stellar radii, in loops covering only small fractions of the stellar surfaces. While the radio properties and the occurrence of X-ray flares suggest the larger emission regions, the observations of time variations leave the ambiguity unresolved

Implementierung eines verlustleistungsoptimierten Dezimators für kaskadierte Sigma-Delta Analog-Digital Umsetzer

Dieser Beitrag stellt die Implementierung eines neuartigen Ansatzes einer effizienten Dezimator-Architektur für kaskadierte Sigma-Delta Modulatoren vor. Die Rekombinationslogik kaskadierter Modulatoren und die Korrektur des Verstärkungsfehlers zeitkontinuierlicher (CT) Modulatoren werden in die erste Stufe des Dezimators integriert. Eine entsprechende Filtertopologie wird hergeleitet und auf einem Hardware-Emulator der Firma Mentor Graphics implementiert. Der Vergleich der vorgeschlagenen Struktur mit einer herkömmlichen Implementierung zeigt eine nennenswerte Verbesserung der Effizienz

Monte Carlo simulation of the transmission of measles: Beyond the mass action principle

We present a Monte Carlo simulation of the transmission of measles within a population sample during its growing and equilibrium states by introducing two different vaccination schedules of one and two doses. We study the effects of the contact rate per unit time $\xi$ as well as the initial conditions on the persistence of the disease. We found a weak effect of the initial conditions while the disease persists when $\xi$ lies in the range 1/L-10/L ($L$ being the latent period). Further comparison with existing data, prediction of future epidemics and other estimations of the vaccination efficiency are provided. Finally, we compare our approach to the models using the mass action principle in the first and another epidemic region and found the incidence independent of the number of susceptibles after the epidemic peak while it strongly fluctuates in its growing region. This method can be easily applied to other human, animals and vegetable diseases and includes more complicated parameters.Comment: 15 pages, 4 figures, 1 table, Submitted to Phys.Rev.

Testing common classical LTE and NLTE model atmosphere and line-formation codes for quantitative spectroscopy of early-type stars

It is generally accepted that the atmospheres of cool/lukewarm stars of spectral types A and later are described well by LTE model atmospheres, while the O-type stars require a detailed treatment of NLTE effects. Here model atmosphere structures, spectral energy distributions and synthetic spectra computed with ATLAS9/SYNTHE and TLUSTY/SYNSPEC, and results from a hybrid method combining LTE atmospheres and NLTE line-formation with DETAIL/SURFACE are compared. Their ability to reproduce observations for effective temperatures between 15000 and 35000 K are verified. Strengths and weaknesses of the different approaches are identified. Recommendations are made as to how to improve the models in order to derive unbiased stellar parameters and chemical abundances in future applications, with special emphasis on Gaia science.Comment: 12 pages, 8 figures; accepted for publication in Journal of Physics: Conference Series, GREAT-ESF Workshop: Stellar Atmospheres in the Gaia Er

String theories as the adiabatic limit of Yang-Mills theory

We consider Yang-Mills theory with a matrix gauge group $G$ on a direct product manifold $M=\Sigma_2\times H^2$, where $\Sigma_2$ is a two-dimensional Lorentzian manifold and $H^2$ is a two-dimensional open disc with the boundary $S^1=\partial H^2$. The Euler-Lagrange equations for the metric on $\Sigma_2$ yield constraint equations for the Yang-Mills energy-momentum tensor. We show that in the adiabatic limit, when the metric on $H^2$ is scaled down, the Yang-Mills equations plus constraints on the energy-momentum tensor become the equations describing strings with a worldsheet $\Sigma_2$ moving in the based loop group $\Omega G=C^\infty (S^1, G)/G$, where $S^1$ is the boundary of $H^2$. By choosing $G=R^{d-1, 1}$ and putting to zero all parameters in $\Omega R^{d-1, 1}$ besides $R^{d-1, 1}$, we get a string moving in $R^{d-1, 1}$. In arXiv:1506.02175 it was described how one can obtain the Green-Schwarz superstring action from Yang-Mills theory on $\Sigma_2\times H^2$ while $H^2$ shrinks to a point. Here we also consider Yang-Mills theory on a three-dimensional manifold $\Sigma_2\times S^1$ and show that in the limit when the radius of $S^1$ tends to zero, the Yang-Mills action functional supplemented by a Wess-Zumino-type term becomes the Green-Schwarz superstring action.Comment: 11 pages, v3: clarifying remarks added, new section on embedding of the Green-Schwarz superstring into d=3 Yang-Mills theory include

The Crowd Classification Problem: Social Dynamics of Binary Choice Accuracy

Decades of research suggest that information exchange in groups and organizations can reliably improve judgment accuracy in tasks such as financial forecasting, market research, and medical decision making. However, we show that improving the accuracy of numeric estimates does not necessarily improve the accuracy of decisions. For binary-choice judgments, also known as classification tasks—for example, yes/no or build/buy decisions—social influence is most likely to grow the majority vote share, regardless of the accuracy of that opinion. As a result, initially, inaccurate groups become increasingly inaccurate after information exchange, even as they signal stronger support. We term this dynamic the “crowd classification problem.” Using both a novel data set and a reanalysis of three previous data sets, we study this process in two types of information exchange: (1) when people share votes only, and (2) when people form and exchange numeric estimates prior to voting. Surprisingly, when people exchange numeric estimates prior to voting, the binary-choice vote can become less accurate, even as the average numeric estimate becomes more accurate. Our findings recommend against voting as a form of decision making when groups are optimizing for accuracy. For those cases where voting is required, we discuss strategies for managing communication to avoid the crowd classification problem. We close with a discussion of how our results contribute to a broader contingency theory of collective intelligence

Corporate tax effects on the quality and quantity of FDI

This paper measures the relative importance of quality and quantity effects of corporate taxation on foreign direct investment. Quantity is affected if corporate taxes reduce the equilibrium stock of foreign capital in a given country. Quality effects arise if taxes decrease the extent to which investment contributes to the corporate tax base and the capital intensity of production. Depending on the sign of the quality effects, the detrimental welfare effects of corporate taxation are either mitigated or aggravated. We derive a number of hypotheses how corporate tax changes may affect the quality of investment. Our hypotheses are then tested using data from a large sample of European multinationals. With regard to corporate tax effects on the corporate tax base, we find that quality effects account for up to fourty per cent of the total effect. With regard to corporate tax effects on labour income, our results suggest that quality effects mitigate the negative quantity effect by nearly sixty percent (as corporate taxes strongly increase the labor intensity of production). An important implication is that governments should not exclusively care about the size of inbound FDI flows but also about their specific characteristics, i.e. their quality

Are "EIT Waves" Fast-Mode MHD Waves?

We examine the nature of large-scale, coronal, propagating wave fronts (``EIT waves'') and find they are incongruous with solutions using fast-mode MHD plane-wave theory. Specifically, we consider the following properties: non-dispersive single pulse manifestions, observed velocities below the local Alfven speed, and different pulses which travel at any number of constant velocities, rather than at the ``predicted'' fast-mode speed. We discuss the possibility of a soliton-like explanation for these phenomena, and show how it is consistent with the above-mentioned aspects.Comment: to be published in the Astrophysical Journa