Análisis de la Política Exterior Rusa en materia energética, comercial y militar hacia la República de Moldavia (Período 2000-2010)

Rusia sufrió grandes cambios tras la desintegración de la URSS en 1991. No obstante, con la llegada de Vladimir Putin al poder, los intereses geoestratégicos de Rusia sobre el espacio postsoviético revivieron con nuevo ímpetu debido a una mayor cantidad de recursos a disposición del Estado. La República de Moldavia es un claro ejemplo del resurgir de la política exterior rusa hacia el espacio postsoviético, siendo incluso, una región clave en la lucha de la Federación Rusa por recuperar su zona de influencia.

Archivo Utopia : Diálogos imaginarios : Encuentros y desencuentros de las vanguardias

Selection of student research papers, course Utopia and Avant-garde, Architecture, EPS, UdG

MAGNETOHYDRODYNAMIC SIMULATIONS OF RECONNECTION AND PARTICLE ACCELERATION: THREE-DIMENSIONAL EFFECTS

Magnetic fields can change their topology through a process known as magnetic reconnection. This process in not only important for understanding the origin and evolution of the large-scale magnetic field, but is seen as a possibly efficient particle accelerator producing cosmic rays mainly through the first-order Fermi process. In this work we study the properties of particle acceleration inserted in reconnection zones and show that the velocity component parallel to the magnetic field of test particles inserted in magnetohydrodynamic (MHD) domains of reconnection without including kinetic effects, such as pressure anisotropy, the Hall term, or anomalous effects, increases exponentially. Also, the acceleration of the perpendicular component is always possible in such models. We find that within contracting magnetic islands or current sheets the particles accelerate predominantly through the first-order Fermi process, as previously described, while outside the current sheets and islands the particles experience mostly drift acceleration due to magnetic field gradients. Considering two-dimensional MHD models without a guide field, we find that the parallel acceleration stops at some level. This saturation effect is, however, removed in the presence of an out-of-plane guide field or in three-dimensional models. Therefore, we stress the importance of the guide field and fully three-dimensional studies for a complete understanding of the process of particle acceleration in astrophysical reconnection environments.

VELOCITY FIELD OF COMPRESSIBLE MAGNETOHYDRODYNAMIC TURBULENCE: WAVELET DECOMPOSITION AND MODE SCALINGS

We study compressible magnetohydrodynamic turbulence, which holds the key to many astrophysical processes, including star formation and cosmic-ray propagation. To account for the variations of the magnetic field in the strongly turbulent fluid, we use wavelet decomposition of the turbulent velocity field into Alfven, slow, and fast modes, which presents an extension of the Cho & Lazarian decomposition approach based on Fourier transforms. The wavelets allow us to follow the variations of the local direction of the magnetic field and therefore improve the quality of the decomposition compared to the Fourier transforms, which are done in the mean field reference frame. For each resulting component, we calculate the spectra and two-point statistics such as longitudinal and transverse structure functions as well as higher order intermittency statistics. In addition, we perform a Helmholtz-Hodge decomposition of the velocity field into incompressible and compressible parts and analyze these components. We find that the turbulence intermittency is different for different components, and we show that the intermittency statistics depend on whether the phenomenon was studied in the global reference frame related to the mean magnetic field or in the frame defined by the local magnetic field. The dependencies of the measures we obtained are different for different components of the velocity; for instance, we show that while the Alfven mode intermittency changes marginally with the Mach number, the intermittency of the fast mode is substantially affected by the change.

Underlying Event measurements in pp collisions at root s=0.9 and 7 TeV with the ALICE experiment at the LHC

We present measurements of Underlying Event observables in pp collisions at root s = 0 : 9 and 7 TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p(T),L-T in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p(T) thresholds: 0.15, 0.5 and 1.0 GeV/c. In the Transverse region we observe an increase in the multiplicity of a factor 2-3 between the lower and higher collision energies, depending on the track p(T) threshold considered. Data are compared to PYTHIA 6.4, PYTHIA 8.1 and PHOJET. On average, all models considered underestimate the multiplicity and summed p(T) in the Transverse region by about 10-30%.

Measurement of prompt J/psi and beauty hadron production cross sections at mid-rapidity in pp collisions at root s=7 TeV

The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.

Particle Acceleration in Turbulence and Weakly Stochastic Reconnection

In this Letter we analyze the energy distribution evolution of test particles injected in three dimensional (3D) magnetohydrodynamic (MHD) simulations of different magnetic reconnection configurations. When considering a single Sweet-Parker topology, the particles accelerate predominantly through a first-order Fermi process, as predicted in [3] and demonstrated numerically in [8]. When turbulence is included within the current sheet, the acceleration rate is highly enhanced, because reconnection becomes fast and independent of resistivity [4,11] and allows the formation of a thick volume filled with multiple simultaneously reconnecting magnetic fluxes. Charged particles trapped within this volume suffer several head-on scatterings with the contracting magnetic fluctuations, which significantly increase the acceleration rate and results in a first-order Fermi process. For comparison, we also tested acceleration in MHD turbulence, where particles suffer collisions with approaching and receding magnetic irregularities, resulting in a reduced acceleration rate. We argue that the dominant acceleration mechanism approaches a second order Fermi process in this case.

Prevalence of genes encoding extracellular proteases in Staphylococcus aureus - important targets triggering immune response in vivo

Proteases of Staphylococcus aureus have long been considered to function as important virulence factors, although direct evidence of the role of particular enzymes remains incomplete and elusive. Here, we sought to provide a collective view of the prevalence of extracellular protease genes in genomes of commensal and pathogenic strains of S. aureus and their expression in the course of human and mouse infection. Data on V8 protease, staphopains A and B, aureolysin, and the recently described and poorly characterized group of six Spl proteases are provided. A phylogenetically diverse collection of 167 clinical isolates was analyzed, resulting in the comprehensive genetic survey of the prevalence of protease-encoding genes. No correlation between identified gene patterns with specific infections was established. Humoral response against the proteases of interest was examined in the sera derived from human patients and from a model mouse infection. The analysis suggests that at least some, if not all, tested proteases are expressed and secreted during the course of infection. Overall, the results presented in this study support the hypothesis that the secretory proteases as a group may contribute to the virulence of S. aureus.

„Neko bi pomislio da se barem delimično sačuva dogma o monarhiji”: Antilatinski traktati Varlaama Kalabrijskog u srpskoslovenskom prevodu 14. veka

Die antilateinischen Traktate von Gregorios Palamas und Barlaam von Kalabrien stellten für die serbischen Übersetzer des 14. Jahrhunderts eine grosse Herausforderung dar – nicht nur wegen ihres dogmatischen Inhalts, sondern auch wegen des ausgeprägt polemischen Charakters ihrer Argumentation. In diesem Aufsatz wird die argumentative Form der zwei Traktate („opuscula“ ) Barlaams von Kalabrien analysiert, die in cod. Dečani 88 enthalten sind (fol. 38r-81r). Der zweite von ihnen (fol. 69v-81r) richtet sich an ein griechisches (orthodoxes) Auditorium; die Anreden an die Lateiner, die sich darin finden, haben rein rhetorischen Charakter. Der erste Traktat (fol. 39r-69r), der während der Unionsverhandlungen des Jahres 1334/1335 entstand, hat jedoch eine für die byzantinische Unionspolemik eher ungewöhnliche Form: der Dialog mit der Gegenseite ist hier keine rhetorische Fiktion, sondern ein ernstes Anliegen des Autors. Dies hat bereits bei der Rezeption des Traktats im griechisch-athonitischen Milieu den Verdacht geweckt, Barlaam habe den Lateinern unzulässige Zugeständnisse gemacht. Barlaam hat versucht, diesen Verdacht durch metakommunikative Kommentare zu entkräften, die ausschliesslich in der serbisch-kirchenslavischen Übersetzung von Dečani 88 enthalten sind. Der Übersetzer der Traktate hat deren argumentative Form im wesentlichen nicht angetastet und nur gelegentlich versucht, die Zugehörigkeit der einzelnen Argumente dem Leser durch Marginalscholien deutlich zu machen.

Partikule kao izazov - za prevodioce i izdavače (na primerlu srpskoslovenskog prevoda antilatinskih traktata Gregorija Palame i Varlaama Kalabrijskog)

Die Übersetzung der antilateinischen Traktate der byzantinischen Theologen Gregorios Palamas (1296-1359) und Barlaam von Kalabrien (1290-1348) Über den Ausgang des Heiligen Geistes entstand in den 60er Jahren des 14. Jahrhunderts. Die älteste Abschrift dieser Übersetzung, die Handschrift Dečani 88, ist zugleich die Arbeitshandschrift der Übersetzer. Sie enthält auf jeder Seite Korrekturen, die einen unmittelbaren Einblick in den Übersetzungsprozess bieten. Aus diesen Korrekturen ist ersichtlich, dass die Übersetzer bei der Wiedergabe nicht nur der theologischen Termini, sondern auch der Partikeln geschwankt haben. Der Autor verbindet diese Schwankungen mit dem Problem der Erhaltung der Argu-mentationsform der Traktate von Gregorios Palamas und Barlaam von Kalabrien in der Über-setzung und analysiert ein konkretes Beispiel: die altserbische Partikel daj.