Stark Broadening of several Ar I Spectral Lines in the Visible Part of the Spectrum

In order to complete data on Stark broadening parameters for Ar I line in the visible spectrum, we determined Stark widths and shifts due to electron, proton, and ionized helium impacts, for nine lines (4191.0, 4259.4, 5912.1, 6043.2, 6045.0, 6752.9, 7503.9, 7514.6, 7724.2 {\AA}), using jK coupling and semiclassical-perturbation theory. The obtained results will enter the STARK-B database, which is a part of Virtual Atomic and Molecular Data Center

Discretization of control law for a class of variable structure control systems

A new method for the discretization of a class of continuous-time variable structure control systems, based on the linear complementarity theory, is proposed. The proposed method consists two steps. In the first step, the motion projected on the sliding manifold (the fast dynamics) is discretized by means of backward Euler time-step method. In the second step, the sampled and hold control law is determined such that the trajectories of the discrete-time closed loop system projected on the sliding manifold coincide with the trajectories of discretized fast dynamics. The discrete-time closed-loop system exhibits discrete-time sliding motion. It means that the trajectories of the discrete-time closed loop system reach the sliding manifold in a finite number of steps and stay on it after that. Also, it is proved that control law is a continuous function. Therefore, the closed loop system is chattering free. The theoretically obtained results are verified on the example of the non-holonomic integrator. \u

Basic Philosophical texts in Medieval Serbia

Medieval Serbian philosophy took shape mostly through the process of translating Byzantine texts and revising the Slavic translations. Apart from the Aristotelian terminological tradition, introduced via the translation of Damascene's Dialectic, there also was, under the influence of the Corpus Areopagiticum and ascetic literature, notably of John Climacus' Ladder, another strain of thought originating from Christian Platonism. Damascene's philosophical chapters, or Dialectic, translated into medieval Serbian in the third quarter of the fourteenth century, not only shows the high standards of translation technique developed in Serbian monastic scriptoria, but testifies to a highly educated readership interested in such a complex theologico-philosophical text with its nuanced terminology. A new theological debate about the impossibility of knowing God led to Gregory Palamas' complex text, The Exposition of the Orthodox Faith. Philosophical texts were frequently copied and much worked on in medieval Serbia, but it is difficult to infer about the actual scope of their influence on the formation and articulation of the worldview of medieval society. As a result of their demanding theoretical complexity, the study of philosophy was restricted to quite narrow monastic, court and urban circles. However, the strongest aspect of the influence of Byzantine thought on medieval society was the liturgy as the central social event of the community. It was through the liturgy that the wording of the translated texts influenced the life of medieval Serbian society

Liberal and Conservative Political Thought in Nineteenth-century Serbia. Vladimir Jovanović and Slobodan Jovanović

Two very influential political philosophers and politicians, Vladimir Jovanović and Slobodan Jovanović, differed considerably in political theory. The father, Vladimir, offered an Enlightenment-inspired rationalist critique of the traditional values underpinning his upbringing. The son, Slobodan, having had a non-traditional, liberal upbringing, gradually-through analyzing and criticizing the epoch's prevail­ing ideas, scientism, positivism and materialism-came up with his own synthesis of traditional and liberal, state and liberty, general and individual. Unlike Vladimir Jovanović, who advocated popular sovereignty, central to the political thought of his son Slobodan was the concept of the state. On the other hand, Slobodan shared his father's conviction that a bicameral system was a prerequisite for the protection of individual liberties and for good governance. Political views based on different political philosophies decisively influenced different understandings of parliamentarianism in nineteenth-century Serbia, which in turn had a direct impact on the domestic political scene and the manner of government

Two-stream-like instability in dilute hot relativistic beams and astrophysical relativistic shocks

Relativistic collisionless shocks are believed to be efficient particle accelerators. Nonlinear outcome of the interaction of accelerated particles that run ahead of the shock, the so-called "precursor", with the unperturbed plasma of the shock upstream, is thought to facilitate additional acceleration of these particles and to possibly modify the hydrodynamic structure of the shock. We explore here the linear growth of kinetic modes appearing in the precursor-upstream interaction in relativistic shocks propagating in non and weakly magnetized plasmas: electrostatic two-stream parallel mode and electrostatic oblique modes. These modes are of particular interest because they are the fastest growing modes known in this type of system. Using a simplified distribution function for a dilute ultra-relativistic beam that is relativistically hot in its own rest frame, yet has momenta that are narrowly collimated in the frame of the cold upstream plasma into which it propagates, we identify the fastest growing mode in the full $k$-space and calculate its growth rate. We consider all types of plasma (pairs and ions-electrons) and beam (charged and charge-neutral). We find that unstable electrostatic modes are present in any type of plasma and for any shock parameters. We further find that two modes, one parallel ($k_\perp=0$) and the other one oblique ($k_\perp \sim k_\|$), are competing for dominance and that either one may dominate the growth rate in different regions of the phase space. The dominant mode is determined mostly by the perpendicular spread of the accelerated particle momenta in the upstream frame, which reflects the shock Lorentz factor. The parallel mode becomes more dominant in shocks with lower Lorentz factors (i.e., with larger momentum spreads). We briefly discuss possible implications of our results for external shocks in gamma-ray burst sources

Chandra and Swift Follow-up Observations of the Intermediate Mass Black Hole in ESO243-49

The brightest Ultra-Luminous X-ray source HLX-1 in the galaxy ESO 243-49 provides strong evidence for the existence of intermediate mass black holes. As the luminosity and thus the mass estimate depend on the association of HLX-1 with ESO 243-49, it is essential to confirm its affiliation. This requires follow-up investigations at wavelengths other than X-rays, which in-turn needs an improved source position. To further reinforce the intermediate mass black hole identification, it is necessary to determine HLX-1's environment to establish whether it could potentially form and nourish a black hole at the luminosities observed. Using the High Resolution Camera onboard Chandra, we determine a source position of RA=01h10m28.3s and Dec=-46d04'22.3". A conservative 95% error of 0.3" was found following a boresight correction by cross-matching the positions of 3 X-ray sources in the field with the 2MASS catalog. Combining all Swift UV/Optical Telescope uvw2 images, we failed to detect a UV source at the Chandra position down to a 3sigma limiting magnitude of 20.25 mag. However, there is evidence that the UV emission is elongated in the direction of HLX-1. This is supported by archival data from GALEX and suggests that the far-UV emission is stronger than the near-UV. This could imply that HLX-1 may be situated near the edge of a star forming region. Using the latest X-ray observations we deduce the mass accretion rate of a 500 Msun black hole with the observed luminosity and show that this is compatible with such an environment.Comment: 10 pages, 3 figures, accepted for publication in ApJL on 12/02/201

Drafting the Constitution of the Kingdom of Serbs, Croats and Slovenes (1920)

The Kingdom of Serbs, Croats and Slovenes was internationally recognized during the Paris Peace Conference in 1919–20. Even though there was neither a provisional nor a permanent constitution of the newly-formed state, factually there was a state as well as a system of governance, represented by supreme bodies, the King and the Parliament. Many draft constitutions were prepared by different political parties and notable individuals. We shall focus on the official Draft Constitution prepared during the premiership of Stojan Protić. He appointed the Drafting Committee as a governmental (multi-ethnic) advisory team of prominent legal experts from different parts of the new state consisting of Professors Slobodan Jovanović (President), Kosta Kumanudi and Lazar Marković (Serbia), Professor Ladislav Polić (Croatia) and Dr Bogumil Vošnjak (Slovenia). After two months of work, the Committee submitted its draft to the Prime Minister. The leading Serbian legal scholar and president of the committee, Slobodan Jovanović (1869–1958), was well-acquainted with the details of Austro-Hungarian and German legal traditions. Since he was an active participant and witness of the events that led to the creation of the new state, while also being an objective and critical historian, it is important to shed light on his firsthand account of the emergence of the state of Serbs, Croats and Slovenes

No snow-plough mechanism during the rapid hardening of supermassive black hole binaries

We present two-dimensional hydrodynamical simulations of the tidal interaction between a supermassive black hole binary with moderate mass ratio, and the fossil gas disc where it is embedded. Our study extends previous one-dimensional height-integrated disc models, which predicted that the density of the gas disc between the primary and the secondary black holes should rise significantly during the ultimate stages of the binary's hardening driven by the gravitational radiation torque. This snow-plough mechanism, as we call it, would lead to an increase in the bolometric luminosity of the system prior to the binary merger, which could be detected in conjunction with the gravitational wave signal. We argue here that the snow-plough mechanism is unlikely to occur. In two-dimensions, when the binary's hardening timescale driven by gravitational radiation becomes shorter than the disc's viscous drift timescale, fluid elements in the inner disc get funneled to the outer disc through horseshoe trajectories with respect to the secondary. Mass leakage across the secondary's gap is thus found to be effective and, as a result, the predicted accretion disc luminosity will remain at roughly the same level prior to merger.Comment: 5 pages, 5 figures, accepted for publication in MNRA

Refunkcionalizacija forme. Modernistički obrt u opusu slikara Leonida Šejke

Works by Belgrade artist Leonid Šejka (1932–1970) are usually considered fantastic, an embodiment of aesthetic ideals of Mediala Art Group he was a member of, an opposition to everything that Modernism stood for with its harsh formalism that expelled object. However, the complexity of Šejka’s opus as artist and theorist allows a different approach. In this paper, we turn to – so far neglected – Šejka‘s positive relation to Modernism, which he saw as a foundation for new aesthetic ideals. He understood that Modernism turned paintings into objects of empty forms void of function. Nevertheless, the future of painting, for him, resided in re-introduction of objects into painting in order to re-establish the necessary form-function relation, preserving, at the same time, Modernist traits. Šejka tried to demonstrate this in his mature works. He wrote about it in a series of writings, which contribute to our understanding of his opus.Works by Belgrade artist Leonid Šejka (1932–1970) are usually considered fantastic, an embodiment of aesthetic ideals of Mediala Art Group he was a member of, an opposition to everything that Modernism stood for with its harsh formalism that expelled object. However, the complexity of Šejka’s opus as artist and theorist allows a different approach. In this paper, we turn to – so far neglected – Šejka‘s positive relation to Modernism, which he saw as a foundation for new aesthetic ideals. He understood that Modernism turned paintings into objects of empty forms void of function. Nevertheless, the future of painting, for him, resided in re-introduction of objects into painting in order to re-establish the necessary form-function relation, preserving, at the same time, Modernist traits. Šejka tried to demonstrate this in his mature works. He wrote about it in a series of writings, which contribute to our understanding of his opus