Structural and thermodynamic properties of different phases of supercooled liquid water.

Computer simulation results are reported for a realistic polarizable potential model of water in the supercooled region. Three states, corresponding to the low density amorphous ice, high density amorphous ice, and very high density amorphous ice phases are chosen for the analyses. These states are located close to the liquid-liquid coexistence lines already shown to exist for the considered model. Thermodynamic and structural quantities are calculated, in order to characterize the properties of the three phases. The results point out the increasing relevance of the interstitial neighbors, which clearly appear in going from the low to the very high density amorphous phases. The interstitial neighbors are found to be, at the same time, also distant neighbors along the hydrogen bonded network of the molecules. The role of these interstitial neighbors has been discussed in connection with the interpretation of recent neutron scattering measurements. The structural properties of the systems are characterized by looking at the angular distribution of neighboring molecules, volume and face area distribution of the Voronoi polyhedra, and order parameters. The cumulative analysis of all the corresponding results confirms the assumption that a close similarity between the structural arrangement of molecules in the three explored amorphous phases and that of the ice polymorphs I(h), III, and VI exists.

Enhanced rewarding properties of morphine, but not cocaine, in beta(arrestin)-2 knock-out mice.

The reinforcing and psychomotor effects of morphine involve opiate stimulation of the dopaminergic system via activation of mu-opioid receptors (muOR). Both mu-opioid and dopamine receptors are members of the G-protein-coupled receptor (GPCR) family of proteins. GPCRs are known to undergo desensitization involving phosphorylation of the receptor and the subsequent binding of beta(arrestins), which prevents further receptor-G-protein coupling. Mice lacking beta(arrestin)-2 (beta(arr2)) display enhanced sensitivity to morphine in tests of pain perception attributable to impaired desensitization of muOR. However, whether abrogating muOR desensitization affects the reinforcing and psychomotor properties of morphine has remained unexplored. In the present study, we examined this question by assessing the effects of morphine and cocaine on locomotor activity, behavioral sensitization, conditioned place preference, and striatal dopamine release in beta(arr2) knock-out (beta(arr2)-KO) mice and their wild-type (WT) controls. Cocaine treatment resulted in very similar neurochemical and behavioral responses between the genotypes. However, in the beta(arr2)-KO mice, morphine induced more pronounced increases in striatal extracellular dopamine than in WT mice. Moreover, the rewarding properties of morphine in the conditioned place preference test were greater in the beta(arr2)-KO mice when compared with the WT mice. Thus, beta(arr2) appears to play a more important role in the dopaminergic effects mediated by morphine than those induced by cocaine.

XUV spectroscopic characterization of warm dense aluminum plasmas generated by the free-electron-laser FLASH

We report on experiments aimed at the generation and characterization of solid density plasmas at the free-electron laser FLASH in Hamburg. Aluminum samples were irradiated with XUV pulses at 13.5 nm wavelength (92 eV photon energy). The pulses with duration of a few tens of femtoseconds and pulse energy up to 100 mu J are focused to intensities ranging between 10(13) and 10(17) W/cm(2). We investigate the absorption and temporal evolution of the sample under irradiation by use of XUV and optical spectroscopy. We discuss the origin of saturable absorption, radiative decay, bremsstrahlung and atomic and ionic line emission. Our experimental results are in good agreement with simulations.

Hierarchy and Expansiveness in Two-Dimensional Subshifts of Finite Type

Subshifts are sets of configurations over an infinite grid defined by a set of forbidden patterns. In this thesis, we study two-dimensional subshifts offinite type (2D SFTs), where the underlying grid is Z2 and the set of for-bidden patterns is finite. We are mainly interested in the interplay between the computational power of 2D SFTs and their geometry, examined through the concept of expansive subdynamics. 2D SFTs with expansive directions form an interesting and natural class of subshifts that lie between dimensions 1 and 2. An SFT that has only one non-expansive direction is called extremely expansive. We prove that in many aspects, extremely expansive 2D SFTs display the totality of behaviours of general 2D SFTs. For example, we construct an aperiodic extremely expansive 2D SFT and we prove that the emptiness problem is undecidable even when restricted to the class of extremely expansive 2D SFTs. We also prove that every Medvedev class contains an extremely expansive 2D SFT and we provide a characterization of the sets of directions that can be the set of non-expansive directions of a 2D SFT. Finally, we prove that for every computable sequence of 2D SFTs with an expansive direction, there exists a universal object that simulates all of the elements of the sequence. We use the so called hierarchical, self-simulating or fixed-point method for constructing 2D SFTs which has been previously used by Ga´cs, Durand, Romashchenko and Shen.

Análisis de la injerencia de la política de la lucha contra el terrorismo en la construccion de política exterior.caso de estudio Pakistan y Ucrania

Este trabajo, contiene una aproximación al fenómeno de la guerra contra el terrorismo, bajo el concepto de Estado Esquizofrénico, que supone el condicionamiento de algunas acciones de los Estados en su interacción en el sistema internacional.

Análisis de la política exterior rusa frente a Abjasia en el período 2000-2008

El objetivo de la presente monografía de grado es analizar la relación entre la identidad dentro de Rusia y la política exterior de dicho Estado hacia la región de Abjasia. Se analiza y explica la manera en que los referentes identitarios dentro de Rusia en el periodo 2000-2008 influyen en las decisiones de política exterior que Rusia tomó hacia Abjasia en el campo militar y político. Se efectúa una revisión de textos (transcripciones de intervenciones y textos escritos) del Presidente y Primer Ministro de la Federación Rusa entre 2000 y 2008 para encontrar los referentes identitarios que determinan el comportamiento de Rusia hacia otros Estados y la forma en que influenciaron sus acciones con respecto a Abjasia.

La construcción de la política exterior de Rusia hacia Serbia: entre el pragmatismo y el Eurasianismo (2007-2015)

Esta monografía defenderá que la Rusia contemporánea cuenta con una ideología formada a partir de los elementos imperiales y religiosos previos a la Unión Soviética además de elementos políticos propios de la URSS como la colectividad y la oposición a occidente. La Rusia de Putin ha recobrado sus capacidades para defender sus intereses en el mundo frente a la injerencia de occidente, y en el caso de Serbia esto se hará evidente a través de la importancia de los lazos culturales e históricos reforzados por los vínculos económicos y estratégicos que representa la presencia de Rusia en Serbia. Los principales autores sobre los que se trabajará son Alexander Dugin y Alexander Panarin.

Ozone climatology using interactive chemistry: results from the Canadian Middle Atmosphere Model

The climatology of ozone produced by the Canadian Middle Atmosphere Model (CMAM) is presented. This three-dimensional global model incorporates the radiative feedbacks of ozone and water vapor calculated on-line with a photochemical module. This module includes a comprehensive gas-phase reaction set and a limited set of heterogeneous reactions to account for processes occurring on background sulphate aerosols. While transport is global, photochemistry is solved from about 400 hPa to the top of the model at ∼95 km. This approach provides a complete and comprehensive representation of transport, emission, and photochemistry of various constituents from the surface to the mesopause region. A comparison of model results with observations indicates that the ozone distribution and variability are in agreement with observations throughout most of the model domain. Column ozone annual variation is represented to within 5–10% of the observations except in the Southern Hemisphere for springtime high latitudes. The vertical ozone distribution is generally well represented by the model up to the mesopause region. Nevertheless, in the upper stratosphere, the model generally underestimates the amount of ozone as well as the latitudinal tilting of ozone isopleths at high latitude. Ozone variability is analyzed and compared with measurements. The comparison shows that the phase and amplitude of the seasonal variation as well as shorter timescale variations are well represented by the model at various latitudes and heights. Finally, the impact of incorporating ozone radiative feedback on the model climatology is isolated. It is found that the incorporation of ozone radiative feedback results in a cooling of ∼8 K in the summer stratopause region, which corrects a warm bias that results when climatological ozone is used.

TRANSITIVE CIRCLE EXCHANGE TRANSFORMATIONS WITH FLIPS

We study the existence of transit we exchange transformations with flips defined on the unit circle S(1). We provide a complete answer to the question of whether there exists a transitive exchange transformation of S(1) defined on a subintervals and having f flips.

Exchange transformations reversing orientation

University of Sao Paulo (USP)

Etniska stereotyper på film : med utgångspunkt i amerikansk film med ryska motiv (2008-2011)

Filmmediet idag är den mest populära formen av masskultur. Med sin världstäckande genomslagskraft och sitt stereotypa porträtterande av verklighet, påverkar filmen världsåskådningen för människor runtom i världen. Ett brinnande ämne i amerikansk film har alltid varit Ryssland, på grund av de politiska motsättningarna och den historiska rivaliteten med USA. Studiens syfte är att undersöka hur Ryssland porträtteras i amerikanska filmer från perioden för presidenterna Dmitrij Medvedevs respektive Barack Obamas första mandatperiod. Frågeställningen för uppsatsen är: hur ser stereotypa föreställningar om Ryssland ut i amerikansk film 2008-2011? Trettiotal filmer med ryska motiv valdes ut för undersökningen och analyserades utifrån de visuella och sociala aspekterna. Resultatet visar på att det förekommer tre skikt av stereotyper om Ryssland: de eviga, som har existerat i hundratals år och spridits av resenärer; stereotyper från epoken för det kalla kriget; och stereotyper om det moderna Ryssland inspirerade av medias nyhetsrapporteringar.

Climate change in Latin America: impacts and mitigation policy options

Includes bibliography.