Excitation of trapped oscillations in discs around black holes

High-frequency quasi-periodic oscillations detected in the light curves of black hole candidates can, according to one model, be identified with hydrodynamic oscillations of the accretion disc. We describe a non-linear coupling mechanism, suggested by Kato, through which inertial waves trapped in the inner regions of accretion discs around black holes are excited. Global warping and/or eccentricity of the disc have a fundamental role in this coupling: they combine with trapped modes, generating negative energy waves, that are damped as they approach the inner edge of the disc or their corotation resonance. As a result of this damping, inertial oscillations are amplified. We calculate the resulting eigenfunctions and their growth rates.Comment: 6 pages, 2 figures; accepted for inclusion in the proceedings of "Cool Discs, Hot Flows: The Varying Faces of Accreting Compact Objects," ed. M. Axelsson (New York: AIP

Warped and eccentric discs around black holes

Accretion discs around black holes in X-ray binary stars are warped if the spin axis of the black hole is not perpendicular to the binary orbital plane. They can also become eccentric through an instability involving a resonance with the binary orbit. Depending on the thickness of the disc and the efficiency of dissipative processes, these global deformations may be able to propagate into the innermost part of the disc in the form of stationary bending or density waves. We describe the solutions in the linear regime and discuss the conditions under which a warp or eccentricity is likely to produce significant activity in the inner region, which may include the excitation of quasi-periodic oscillations.Comment: 6 pages, 3 figures; accepted for inclusion in the proceedings of "Cool Discs, Hot Flows: The Varying Faces of Accreting Compact Objects," ed. M. Axelsson (New York: AIP

Initial pseudo-steady state & asymptotic KPZ universality in semiconductor on polymer deposition

The Kardar-Parisi-Zhang (KPZ) class is a paradigmatic example of universality in nonequilibrium phenomena, but clear experimental evidences of asymptotic 2D-KPZ statistics are still very rare, and far less understanding stems from its short-time behavior. We tackle such issues by analyzing surface fluctuations of CdTe films deposited on polymeric substrates, based on a huge spatio-temporal surface sampling acquired through atomic force microscopy. A \textit{pseudo}-steady state (where average surface roughness and spatial correlations stay constant in time) is observed at initial times, persisting up to deposition of $\sim 10^{4}$ monolayers. This state results from a fine balance between roughening and smoothening, as supported by a phenomenological growth model. KPZ statistics arises at long times, thoroughly verified by universal exponents, spatial covariance and several distributions. Recent theoretical generalizations of the Family-Vicsek scaling and the emergence of log-normal distributions during interface growth are experimentally confirmed. These results confirm that high vacuum vapor deposition of CdTe constitutes a genuine 2D-KPZ system, and expand our knowledge about possible substrate-induced short-time behaviors.Comment: 13 pages, 8 figures, 2 table

Transthyretin familial amyloid polyneuropathy impact on health-related quality of life

info:eu-repo/semantics/publishedVersio

Temperature effect on (2+1) experimental Kardar-Parisi-Zhang growth

We report on the effect of substrate temperature (T) on both local structure and long-wavelength fluctuations of polycrystalline CdTe thin films deposited on Si(001). A strong T-dependent mound evolution is observed and explained in terms of the energy barrier to inter-grain diffusion at grain boundaries, as corroborated by Monte Carlo simulations. This leads to transitions from uncorrelated growth to a crossover from random-to-correlated growth and transient anomalous scaling as T increases. Due to these finite-time effects, we were not able to determine the universality class of the system through the critical exponents. Nevertheless, we demonstrate that this can be circumvented by analyzing height, roughness and maximal height distributions, which allow us to prove that CdTe grows asymptotically according to the Kardar-Parisi-Zhang (KPZ) equation in a broad range of T. More important, one finds positive (negative) velocity excess in the growth at low (high) T, indicating that it is possible to control the KPZ non-linearity by adjusting the temperature.Comment: 6 pages, 5 figure

Evolution of Universe to the present inert phase

We assume that current state of the Universe can be described by the Inert Doublet Model, containing two scalar doublets, one of which is responsible for EWSB and masses of particles and the second one having no couplings to fermions and being responsible for dark matter. We consider possible evolutions of the Universe to this state during cooling down of the Universe after inflation. We found that in the past Universe could pass through phase states having no DM candidate. In the evolution via such states in addition to a possible EWSB phase transition (2-nd order) the Universe sustained one 1-st order phase transition or two phase transitions of the 2-nd order.Comment: 19 pages, 3 figure

Decline in glutathione peroxidase and cytoplasmic catalases by lindane may cause an increase of reactive oxygen species in Saccharomyces cerevisiae

Lindane or gamma 1α,2α,3β,4α,5α,6β-hexachlorocyclohexane is an organochlorine insecticide, persistent in soils and aquifers, lipophilic, chemically and biochemically inert that accumulates along the human food chain. It is commonly used on a wide variety of crops, in warehouses, in public health to control insect-borne diseases, and (with fungicides) as a seed treatment. Lindane is also presently used in lotions, creams, and shampoos for the control of lice and mites (scabies) in humans. Several chemicals as lindane, toxic for aquatic organisms, birds and mammals have been in the news recently, since the European Union intend to ban it. Therefore it is urgent to clarify the toxicological mechanisms of this compound in eukaryotic cells. Thus the main purpose of this work was to evaluate the effects of lindane in the wine wild-type Saccharomyces cerevisiae UE-ME3 of Alentejo musts, Portugal, a unicellular eukaryotic organism, described as resistant to the presence of pesticides or metals. Cells at mid-exponential phase were inoculated in YEPD medium with 2 % (w/v) glucose and incubated during 72 h in a water bath with orbital shaking, at 28 ºC, in the absence or in presence of 5 and 50 μM lindane. Samples from each treatment were used to obtain growth curves, wet weight and to prepare post-12000 g supernatant, used for determination of reactive oxygen species (ROS) [1] by fluorimetry and alkaline phosphatase (ALP) [2], glutathione peroxidase (GPx) [3], selenium-dependent glutathione peroxidase (Se-GPx) [3] and cytoplasmic catalase (CAT T) [4] activities as well as pellet for determination of peroxisomal catalase (CAT A) [4] activities by spectrophotometry. The results show that lindane inhibited cell growth of S. cerevisiae UE-ME3, causing a decrease in the biomass produced along 72 h, as well as cell viability from 24 h of assay. On the other hand, was detected an increase in the ROS content of post-12,000 g sediment of cells exposed to 5 μM lindane and post-12000 g supernatant of cells subjected to any exposure conditions, eventually conditioned by a decline in GPx and CAT T activities, which has become the detoxification of hydrogen peroxide less effective. The increase in the CAT A activity without significant changes in the ALP and Se-GPx activities justified, in part, the increase in ROS levels of S. cerevisiae exposed to lindane, as well as the loss of cell viability due to inadequate response of glutathione cycle or cells signaling pathways that assure lipid biosynthesis

Intangibles as innovative drivers for competitive businesses

This paper aims to identify the impact of intangible resources as drivers of firms’ performance and profitability, in the major technological firms in the world. Using information from the major technological firms for a four years economic period, a set of intellectual capital proxies were identified and regressed against the major performance and profitability indicators. The regression model embodies a set of knowledge-based resources intangible (e.g. goodwill, licenses and patents, software and R&D, and advertising expenses) and human capital proxies, aiming to identify potential disaggregated effects of intangibles those key performance indicators. Broadly, results suggest the existence of effective isolated effect for some variables, in particular for intangibles recognized in the financial reporting. Furthermore, this research also suggests that the capitalization of intangible resources can be associated with region and corresponding accounting standards used in the preparation of the financial reporting.info:eu-repo/semantics/acceptedVersio