10,630 research outputs found

    Colonel Utley\u27s Emancipation - Or, How Lincoln Offered to Buy a Slave

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    The reputation of Abraham Lincoln has see-sawed over the last half-century on the fulcrum of race, and the results have not been happy for that reputation. As Gerald Prokopowicz has written, the big question about Lincoln and slavery runs today like this: Was Lincoln really the Great Emancipator that we have traditionally been brought up to admire, or was he just a clever, lying, racist, white male politician who had no interest in the well-being of black America other than when it served his political interests? No longer is it necessary, as one historian has wryly remarked, for politicians to get right with Lincoln. Historians now yearn to get right with Frederick Douglass, and to judge by the recent freshet of literature on Lincoln and Douglass, it is now incumbent on Lincoln to be gotten right with Frederick Douglass, too. One of the most damaging accusations leveled against the possibility of justifying Lincoln on race appears in Lerone Bennett\u27s infamous screen, Forced into Glory: Abraham Lincoln\u27s White Dream, where, as the finale to a battery of accusations of racism, Bennett\u27s Lincoln personally ordered Union officers to return runaway slaves to slavemasters and turned a blind eye to Kentuckians, for example, who were selling and reenslaving African-Americans freed by the war and congressional acts. [excerpt

    Analysis of Computer Science Communities Based on DBLP

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    It is popular nowadays to bring techniques from bibliometrics and scientometrics into the world of digital libraries to analyze the collaboration patterns and explore mechanisms which underlie community development. In this paper we use the DBLP data to investigate the author's scientific career and provide an in-depth exploration of some of the computer science communities. We compare them in terms of productivity, population stability and collaboration trends.Besides we use these features to compare the sets of topranked conferences with their lower ranked counterparts.Comment: 9 pages, 7 figures, 6 table

    Is Tsallis thermodynamics nonextensive?

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    Within the Tsallis thermodynamics' framework, and using scaling properties of the entropy, we derive a generalization of the Gibbs-Duhem equation. The analysis suggests a transformation of variables that allows standard thermodynamics to be recovered. Moreover, we also generalize Einstein's formula for the probability of a fluctuation to occur by means of the maximum statistical entropy method. The use of the proposed transformation of variables also shows that fluctuations within Tsallis statistics can be mapped to those of standard statistical mechanics.Comment: 4 pages, no figures, revised version, new title, accepted in PR

    Observations of transients and pulsars with LOFAR international stations

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    The LOw FRequency ARray - LOFAR is a new radio telescope that is moving the science of radio pulsars and transients into a new phase. Its design places emphasis on digital hardware and flexible software instead of mechanical solutions. LOFAR observes at radio frequencies between 10 and 240 MHz where radio pulsars and many transients are expected to be brightest. Radio frequency signals emitted from these objects allow us to study the intrinsic pulsar emission and phenomena such as propagation effects through the interstellar medium. The design of LOFAR allows independent use of its stations to conduct observations of known bright objects, or wide field monitoring of transient events. One such combined software/hardware solution is called the Advanced Radio Transient Event Monitor and Identification System (ARTEMIS). It is a backend for both targeted observations and real-time searches for millisecond radio transients which uses Graphical Processing Unit (GPU) technology to remove interstellar dispersion and detect millisecond radio bursts from astronomical sources in real-time using a single LOFAR station.Comment: To appear in the proceedings of the Electromagnetic Radiation from Pulsars and Magnetars conference, Zielona Gora, 2012. 4 pages, 1 figur

    Spectral variation in the X-ray pulsar GX 1+4 during a low-flux episode

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    The X-ray pulsar GX 1+4 was observed with the RXTE satellite for a total of 51ks between 1996 July 19 - 21. During this period the flux decreased smoothly from an initial mean level of ~ 6 X 10^36 erg/s to a minimum of ~ 4 X 10^35 erg/s (2-60 keV, assuming a source distance of 10 kpc) before partially recovering towards the initial level at the end of the observation. BATSE pulse timing measurements indicate that a torque reversal took place approximately 10 d after this observation. Both the mean pulse profile and the photon spectrum varied significantly. The observed variation in the source may provide important clues as to the mechanism of torque reversals. The single best-fitting spectral model was based on a component originating from thermal photons with kT ~ 1 keV Comptonised by a plasma of temperature kT \~ 7 keV. Both the flux modulation with phase during the brightest interval and the evolution of the mean spectra over the course of the observation are consistent with variations in this model component; with, in addition, a doubling of the column density nH contributing to the mean spectral change. A strong flare of duration 50 s was observed during the interval of minimum flux, with the peak flux ~ 20 times the mean level. Although beaming effects are likely to mask the true variation in Mdot thought to give rise to the flare, the timing of a modest increase in flux prior to the flare is consistent with dual episodes of accretion resulting from successive orbits of a locally dense patch of matter in the accretion disc.Comment: 8 pages, 3 figures, submitted to MNRA

    Algorithm Developments for Discrete Adjoint Methods

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    This paper presents a number of algorithm developments for adjoint methods using the 'discrete' approach in which the discretisation of the non-linear equations is linearised and the resulting matrix is then transposed. With a new iterative procedure for solving the adjoint equations, exact numerical equivalence is maintained between the linear and adjoint discretisations. The incorporation of strong boundary conditions within the discrete approach is discussed, as well as a new application of adjoint methods to linear unsteady flow in turbomachinery

    Who pays the taxes?

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    The European Union is legally entitled to the revenue from (1) agricultural and sugar levies, (2) customs duties, (3) a 1 percent rate on each Member States' value added tax base, and (4) a resource on the basis of GNP. Currently, the Union is actively involved in the search for a fifth own revenue source. Therefore, the European Commission (DG XIX) has invited the authors to trace 'who pays the taxes'. As requested, our report gives a general account of methods to investigate impacts of taxation. More specifically, we have estimated the incidence of national tax systems (Germany, the Netherlands, Spain and the United Kingdom), and the incidence of present own resources and prospective new (tax) resources of the European Union. Up till now, such information was not (readily) available.tax incidence in the European Union, prospective new EU tax resources

    Who pays the taxes?

    Get PDF
    The European Union is legally entitled to the revenue from (1) agricultural and sugar levies, (2) customs duties, (3) a 1 percent rate on each Member States' value added tax base, and (4) a resource on the basis of GNP. Currently, the Union is actively involved in the search for a fifth own revenue source. Therefore, the European Commission (DG XIX) has invited the authors to trace 'who pays the taxes'. As requested, our report gives a general account of methods to investigate impacts of taxation. More specifically, we have estimated the incidence of national tax systems (Germany, the Netherlands, Spain and the United Kingdom), and the incidence of present own resources and prospective new (tax) resources of the European Union. Up till now, such information was not (readily) available.tax incidence in the European Union, prospective new EU tax resources

    Program for computing partial pressures from residual gas analyzer data

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    A computer program for determining the partial pressures of various gases from residual-gas-analyzer data is given. The analysis of the ion currents of 18 m/e spectrometer peaks allows the determination of 12 gases simultaneously. Comparison is made to ion-gage readings along with certain other control information. The output data are presented in both tabular and graphical form

    Acceleration of a Full-scale Industrial CFD Application with OP2

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