A Stationary, Mixing and Perturbative Counterexample to the 0-1-law for Random Walk in Random Environment in Two Dimensions

We construct a two-dimensional counterexample of a random walk in random environment (RWRE). The environment is stationary, mixing and perturbative, and the corresponding RWRE has non-trivial probability to wander off to the upper right. This is in contrast to the 0-1-law that holds for i.i.d.\ environments

Could the library be dismantled/role of unique holdings in modern times

I have been asked by administration, how much of our collection could go into storage. They optimistically hoping for a room or two for faculty/staff offices, as some buildings need renovation or need to be closed due to safety issues. Clearly, much of the population believes that all/most library materials are available on-line – free. I will present the results of our survey’s of material held and available on-line and space “freed” thanks to archiving. How little space is freed

Pre-entry advertising, entry deterrence and multi-informational signaling

Advertising is commonly regarded as a strategic tool to increase demand and steal business from competitors. The present work studies the competitive effects of advertising in a two-period game with incomplete information about the opponent's cost structure. Bagwell and Ramey (1988) showed that deterring entry is possible by signaling lower costs even if the post-entry game is independent of the pre-entry advertising decision. Assuming that pre-entry advertising by an entrant affects the post-entry game, then the incumbent is forced to do more than in the Bagwell/Ramey case to deter entry; he needs to distort costs downwards more extensively. On the other hand, introductory advertising does not facilitate entry if the entrant learns from the signal that competition with the incumbent is unprofitable. In this case, the entrant abstains from entry after performing introductory advertisng. Furthermore, if the incumbent has private information on cost and advertising effectiveness, then he can deter entry by acting as if he had lower production costs and a better advertising effectiveness. In this scenario, entry deterrence is associated with overinvestment in advertising but not with limit pricing, which is a new prediction. The use of multi-informational signals, i.e. pooled information on more than one type of private information transferred by one signal, is methodologically a new development of the classical signaling game.advertising, entry deterrence, advertising effectiveness, pre-entry advertising, signaling

Chemical investigation of light induced DNA bipyrimidine damage and repair

In all organisms, genetic information is stored in DNA and RNA. Both of these macromolecules are damaged by many exogenous and endogenous events, with UV irradiation being one of the major sources of damage. The major photolesions formed are the cyclobutane pyrimidine dimers (CPD), pyrimidine–pyrimidone-(6-4)-photoproducts, Dewar valence isomers and, for dehydrated spore DNA, 5-(a-thyminyl)-5,6-dihydrothymine (SP). In order to be able to investigate how nature’s repair and tolerance mechanisms protect the integrity of genetic information, oligonucleotides containing sequence and site-specific UV lesions are essential. This tutorial review provides an overview of synthetic procedures by which these oligonucleotides can be generated, either through phosphoramidite chemistry or direct irradiation of DNA. Moreover, a brief summary on their usage in analysing repair and tolerance processes as well as their biological effects is provided

Absence of superconductivity in iron polyhydrides at high pressures

Recently, C. M. Pépin et al. [Science 357, 382 (2017)] reported the formation of several new iron polyhydrides FeHx at pressures in the megabar range and spotted FeH5, which forms above 130 GPa, as a potential high-Tc superconductor because of an alleged layer of dense metallic hydrogen. Shortly after, two studies by A. Majumdar et al. [Phys. Rev. B 96, 201107 (2017)] and A. G. Kvashnin et al. [J. Phys. Chem. C 122, 4731 (2018)] based on ab initio Migdal-Eliashberg theory seemed to independently confirm such a conjecture. We conversely find, on the same theoretical-numerical basis, that neither FeH5 nor its precursor, FeH3, shows any conventional superconductivity and explain why this is the case. We also show that superconductivity may be attained by transition-metal polyhydrides in the FeH3 structure type by adding more electrons to partially fill one of the Fe-H hybrid bands (as, e.g., in NiH3). Critical temperatures, however, will remain low because the d-metal bonding, and not the metallic hydrogen, dominates the behavior of electrons and phonons involved in the superconducting pairing in these compounds

Power-Colours: Simple X-ray Binary Variability Comparison

We demonstrate a new method of variability classification using observations of black hole X-ray binaries. Using `power colours' -- ratios of integrated power in different Fourier frequency bands -- we can clearly differentiate different canonical black hole states as the objects evolve during outburst. We analyse (~ 2400) Rossi X-ray Timing Explorer observations of 12 transient low mass black hole X-ray binaries and find that the path taken around the power colour-colour diagram as the sources evolve is highly consistent from object to object. We discuss how the consistency observed in the power colour-colour diagram between different objects allows for easy state classification based on only a few observations, and show how the power-spectral shapes can be simply classified using a single parameter, the power-spectral `hue'. To illustrate the benefits of our simple model-independent approach, we show that the persistent high mass X-ray binary Cyg X-1 shows very similar power-spectral evolution to the transient black hole sources, with the main difference being caused by a combination of a lack of quasi-periodic oscillations and an excess of low-frequency power-law noise in the Cyg X-1 power spectra during the transitional state. We also compare the transient objects to the neutron star atoll source Aquila X-1, demonstrating that it traces a different path in the power colour-colour plot. Thus, power-colours could be an effective method to classify newly discovered X-ray binaries.Comment: 13 pages, 9 figures, accepted by MNRA

Arteriogenesis versus angiogenesis: similarities and differences

Cardiovascular diseases account for more than half of total mortality before the age of 75 in industrialized countries. To develop therapies promoting the compensatory growth of blood vessels could be superior to palliative surgical surgical interventions. Therefore, much effort has been put into investigating underlying mechanisms. Depending on the initial trigger, growth of blood vessels in adult organisms proceeds via two major processes, angiogenesis and arteriogenesis. While angiogenesis is induced by hypoxia and results in new capillaries, arteriogenesis is induced by physical forces, most importantly fluid shear stress. Consequently, chronically elevated fluid shear stress was found to be the strongest trigger under experimental conditions. Arteriogenesis describes the remodelling of pre-existing arterio-arteriolar anastomoses to completely developed and functional arteries. In both growth processes, enlargement of vascular wall structures was proposed to be covered by proliferation of existing wall cells. Recently, increasing evidence emerges, implicating a pivotal role for circulating cells, above all blood monocytes, in vascular growth processes. Since it has been shown that monocytes/macrophage release a cocktail of chemokines, growth factors and proteases involved in vascular growth, their contribution seems to be of a paracrine fashion. A similar role is currently discussed for various populations of bone-marrow derived stem cells and endothelial progenitors. In contrast, the initial hypothesis that these cells -after undergoing a (trans-)differentiation- contribute by a structural integration into the growing vessel wall, is increasingly challenged