High-Temperature Dielectric Response of (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3: Does Burns Temperature Exist in Ferroelectric Relaxors?

It has been considered that polar nanoregions in relaxors form at Burns temperature Td approx 600 K. High-temperature dielectric investigations of Pb(Mg1/3Nb2/3)O3 (PMN) and 0.7PMN-0.3PbTiO3 reveal, however, that the dielectric dispersion around 600 K appears due to the surface-layer contributions. The intrinsic response, analyzed in terms of the universal scaling, imply much higher Td or formation of polar nanoregions in a broad temperature range, while high dielectric constants manifest that polar order exists already at the highest measured temperatures of 800 K. The obtained critical exponents indicate critical behavior associated with universality classes typically found in spin glasses

Two-Dimensional Supersymmetric Sigma Models on Almost-Product Manifolds and Non-Geometry

We show that the superconformal symmetries of the (1,1) sigma model decompose into a set of more refined symmetries when the target space admits projectors $P_{\pm}$, and the orthogonal complements $Q_{\pm}$, covariantly constant with respect to the two natural torsionful connections $\nabla^{(\pm)}$ that arise in the sigma model. Surprisingly the new symmetries still close to form copies of the superconformal algebra, even when the projectors are not integrable, so one is able to define a superconformal theory not associated with a particular geometry, but rather with non-integrable projectors living on a larger manifold. We show that this notion of non-geometry encompasses the locally non-geometric examples that arise in the T-duality inspired doubled formulations, with the benefit that it is more generally applicable, as it does not depend on the existence of isometries, or invariant structures beyond $P_{\pm}$ and $Q_{\pm}$. We derive the conditions for (2,2) supersymmetry in the projective sense, thus extending the relation between (2,2) theories and bi-Hermitian target spaces to the non-geometric setting. In the bosonic subsector we propose a BRST type approach to defining the physical degrees of freedom in the non-geometric scenario.Comment: 27 pages; version published in Classical and Quantum Gravity (excluding the BV appendix

Protozoa as reservoirs for pathogenic bacteria

Sve su nam više poznate interakcije između patogenih bakterija i protozoa. Neke bakterije postaju patogene tek nakon života unutar praživotinje. Protozoa je skupina unutar koje su neke vrste vrlo dobro prilagođene na razne uvjete na Zemlji. Pronađeno je da neke bakterije iskorištavaju tu rasprostranjenost protozoa u svoju korist i tako si šire areal. Također razvijaju složene patogene sposobnosti kako bi mogle zaraziti kompleksnije organizme. U ovome se radu koriste L. pneumophila i S. enterica kao uzorci patogenih bakterija, koje ulaze u simbiozu s protozoa (Acanthamoeba castellani i rod Tetrahymena). Ove interakcije su značajne za razvoj i preživljavanje tih bakterija. Nama su takva istraživanja bitna da bi mogli predvidjeti, a i potencijalno kontrolirati slijedeće korake patogenih bakterija.Interactions between pathogenic bacteria and protozoa are becoming thoroughly understood. There are bacteria which become pathogenic only after they interact with a protozoa. Protozoa are microorganisms that are very well adapted to the various conditions on Earth today. It has been proven that a variety of bacteria are using these adaptations for their own advantages. These advantages are a wider living area under a big variety of environmental conditions and a more complex system of infection that allows them to infect more complex organisms. In this essay L. pneumophila and S. enterica are the two bacteria used as role models for prokaryotic and eukaryotic interactions, while in the same time Acanthamoeba castellani and the genus Tetrahymena are used as role models for these interactions as protozoans. Interactions between protozoa and bacteria have been well known of but it is only today that we are realizing their significance in bacteria development and survival. Research in this field may be vital for holding a dominant role against desease caused by pathogenic bacteria

The Underlying Term Is Democracy: An Interview With Julian Stallabrass

In Art Incorporated, you seek to debunk the myth of the artworld as autonomous of the market forces of global capitalism. Instead, you argue, works of art have become yet another commodity. However, one could say that works of art have always been commodities as well as objects of aesthetic appreciation. What makes the problem pertinent now, in the age of artists like Takashi Murakami, Jeff Koons and Damien Hirst

Schopenhauer On The Epistemological Value Of Art

Art, as discussed in the third book of Arthur Schopenhauer’s The World as Will and Representation, plays a double role in his philosophical system. On one hand, beholding an object of aesthetic worth provides the spectator with a temporary cessation of the otherwise incessant suffering that Schopenhauer takes life to be; on the other, art creates an epistemological bridge between ourselves and the world as it really is: unlike science which only studies relations between things, contemplation of art leads to knowledge of that which is “alone really essential to the world, the true content of its phenomena.” (WWR1: 184) It is this second aspect of Schopenhauer's aesthetics that is both appealing and curious: while Schopenhauer's aesthetics and epistemology are both rooted in his picture of the world as Will, which is (taken at face value) deeply counter-intuitive, it yet seems to me that by assigning epistemic value to art, he manages to capture the quality of profundity with which certain works of art strike us – a profundity that is accounted for neither by reference to mere enjoyment nor by reference to paraphrasable, propositional knowledge