8,758 research outputs found

    Criminal use of cryptocurrencies:a great new threat or is cash still king?

    Get PDF

    The Eight Points - A Reinterpretation of Deep Ecology

    Get PDF
    Naess and Sessions “Deep Ecology Platform” provided a loose framework for a movement that was gaining momentum after a series of successful social and political actions and events throughout the 1970s and early 1980s. Most of the points are essentially adopted from Naess’ earlier work, which provided the basis for a number of the core concepts expressed in the later eight points and is largely an expression of a movement that sought to create a shift in consciousness of society towards the natural world. It is probably better understood as a lose framework that encapsulates a world view and perspective of nature which is better understood as an aesthetic movement rather than a moral or ethical movement

    Period-colour and amplitude-colour relations in classical Cepheid variables IV: The multi-phase relations

    Full text link
    The superb phase resolution and quality of the OGLE data on LMC and SMC Cepheids, together with existing data on Galactic Cepheids, are combined to study the period-colour (PC) and amplitude-colour (AC) relations as a function of pulsation phase. Our results confirm earlier work that the LMC PC relation (at mean light) is more consistent with two lines of differing slopes, separated at a period of 10 days. However, our multi-phase PC relations reveal much new structure which can potentially increase our understanding of Cepheid variables. These multi-phase PC relations provide insight into why the Galactic PC relation is linear but the LMC PC relation is non-linear. This is because the LMC PC relation is shallower for short (log P < 1) and steeper for long (log P > 1) period Cepheids than the corresponding Galactic PC relation. Both of the short and long period Cepheids in all three galaxies exhibit the steepest and shallowest slopes at phases around 0.75-0.85, respectively. A consequence is that the PC relation at phase ~0.8 is highly non-linear. Further, the Galactic and LMC Cepheids with log P > 1 display a flat slope in the PC plane at phases close to the maximum light. When the LMC period-luminosity (PL) relation is studied as a function of phase, we confirm that it changes with the PC relation. The LMC PL relation in V- and I-band near the phase of 0.8 provides compelling evidence that this relation is also consistent with two lines of differing slopes joined at a period close to 10 days.Comment: 12 pages, 1 table and 13 figures, MNRAS accepte

    Quantitative spectroscopy of extreme helium stars - Model atmospheres and a non-LTE abundance analysis of BD+10∘^\circ2179?

    Get PDF
    Extreme helium stars (EHe stars) are hydrogen-deficient supergiants of spectral type A and B. They are believed to result from mergers in double degenerate systems. In this paper we present a detailed quantitative non-LTE spectral analysis for BD+10∘^\circ2179, a prototype of this rare class of stars, using UVES and FEROS spectra covering the range from ∌\sim3100 to 10 000 {\AA}. Atmosphere model computations were improved in two ways. First, since the UV metal line blanketing has a strong impact on the temperature-density stratification, we used the Atlas12 code. Additionally, We tested Atlas12 against the benchmark code Sterne3, and found only small differences in the temperature and density stratifications, and good agreement with the spectral energy distributions. Second, 12 chemical species were treated in non-LTE. Pronounced non-LTE effects occur in individual spectral lines but, for the majority, the effects are moderate to small. The spectroscopic parameters give TeffT_\mathrm{eff} = 17 300±\pm300 K and log⁥g\log g = 2.80±\pm0.10, and an evolutionary mass of 0.55±\pm0.05 M⊙M_\odot. The star is thus slightly hotter, more compact and less massive than found in previous studies. The kinematic properties imply a thick-disk membership, which is consistent with the metallicity [[Fe/H]≈−1]\approx-1 and α\alpha-enhancement. The refined light-element abundances are consistent with the white dwarf merger scenario. We further discuss the observed helium spectrum in an appendix, detecting dipole-allowed transitions from about 150 multiplets plus the most comprehensive set of known/predicted isolated forbidden components to date. Moreover, a so far unreported series of pronounced forbidden He I components is detected in the optical-UV.Comment: Accepted for publication in MNRAS, 26 pages, 19 Figure

    Partial observability during predictions of the opponent's movements in an RTS game

    No full text
    Abstract — In RTS-style games it is important to be able to predict the movements of the opponent’s forces to have the best chance of performing appropriate counter-moves. Resorting to using perfect global state information is generally considered to be ‘cheating ’ by the player, so to perform such predictions scouts (or observers) must be used to gather information. This means being in the right place at the right time to observe the opponent. In this paper we show the effect of imposing partial observability onto an RTS game with regard to making predictions, and we compare two different mechanisms that decide where best to direct the attention of the observers to maximise the benefit of predictions. I
    • 

    corecore