Modeling the IDV emissions of the BL Lac Objects with a Langevin type stochastic differential equation

In this paper, we introduce a simplified model for explaining the observations of the optical intraday variability (IDV) of the BL Lac Objects. We assume that the source of the IDV are the stochastic oscillations of an accretion disk around a supermassive black hole. The Stochastic Fluctuations on the vertical direction of the accretion disk are described by using a Langevin type equation with a damping term and a random, white noise type force. Furthermore, the preliminary numerical simulation results are presented, which are based on the numerical analysis of the Langevin stochastic differential equation.Comment: 4 pages, 4 figures, accepted for publication in J. Astrophys. Ast

Metabolic and cardiac adaptation to chronic pharmacologic blockade of facilitative glucose transport in murine dilated cardiomyopathy and myocardial ischemia

Abstract GLUT transgenic and knockout mice have provided valuable insight into the role of facilitative glucose transporters (GLUTs) in cardiovascular and metabolic disease, but compensatory physiological changes can hinder interpretation of these models. To determine whether adaptations occur in response to GLUT inhibition in the failing adult heart, we chronically treated TG9 mice, a transgenic model of dilated cardiomyopathy and heart failure, with the GLUT inhibitor ritonavir. Glucose tolerance was significantly improved with chronic treatment and correlated with decreased adipose tissue retinol binding protein 4 (RBP4) and resistin. A modest improvement in lifespan was associated with decreased cardiomyocyte brain natriuretic peptide (BNP) expression, a marker of heart failure severity. GLUT1 and −12 protein expression was significantly increased in left ventricular (LV) myocardium in ritonavir-treated animals. Supporting a switch from fatty acid to glucose utilization in these tissues, fatty acid transporter CD36 and fatty acid transcriptional regulator peroxisome proliferator-activated receptor α (PPARα) mRNA were also decreased in LV and soleus muscle. Chronic ritonavir also increased cardiac output and dV/dt-d in C57Bl/6 mice following ischemia-reperfusion injury. Taken together, these data demonstrate compensatory metabolic adaptation in response to chronic GLUT blockade as a means to evade deleterious changes in the failing heart

What is the role of ethics in accreditation guidelines for engineering programmes in Europe?

The Washington Accord emphasises the role of ethical and societal considerations in the practice of engineering. Increasingly, national accrediting bodies are alsoexpecting to see evidence in the delivery and assessment of ethics throughoutengineering programmes. Nevertheless, there is still little known on how the process of evaluating ethics can best serve the function of accreditation ensuring quality assurance and quality improvement. The aim of this paper is to look at the top-down approach and analyse what role engineering ethics plays in national accreditation documentations in Europe. A multi-country analysis of how and where ethics appears in the systems of accreditation was carried out for the UK, Ireland, France, and Switzerland. The competencies, programme outcomes or learning outcomes were reviewed and explicit or implicit references to ethics education were identified. A quantitative and qualitative word analysis was carried out by extracting verbs and comparing verb definitions that were stated. Verbs were categorised under Doing actions, Thinking actions or both and compared to Bloom’s Taxonomy of Learning. In all cases, ethics was explicitly mentioned however limited to 1 or 2 sections of the documents reviewed. The majority of statements linking to ethics were implicit,opening room for interpretation. A more conscious effort to engage engineeringethics in all aspects of engineering programmes as well as using higher levels ofBloom’s taxonomy should be made where engineering ethics education is applied in practice

What is the role of ethics in accreditation guidelines for engineering programmes in Europe?

The Washington Accord emphasises the role of ethical and societal considerations in the practice of engineering. Increasingly, national accrediting bodies are alsoexpecting to see evidence in the delivery and assessment of ethics throughoutengineering programmes. Nevertheless, there is still little known on how the process of evaluating ethics can best serve the function of accreditation ensuring quality assurance and quality improvement. The aim of this paper is to look at the top-down approach and analyse what role engineering ethics plays in national accreditation documentations in Europe. A multi-country analysis of how and where ethics appears in the systems of accreditation was carried out for the UK, Ireland, France, and Switzerland. The competencies, programme outcomes or learning outcomes were reviewed and explicit or implicit references to ethics education were identified. A quantitative and qualitative word analysis was carried out by extracting verbs and comparing verb definitions that were stated. Verbs were categorised under Doing actions, Thinking actions or both and compared to Bloom’s Taxonomy of Learning. In all cases, ethics was explicitly mentioned however limited to 1 or 2 sections of the documents reviewed. The majority of statements linking to ethics were implicit,opening room for interpretation. A more conscious effort to engage engineeringethics in all aspects of engineering programmes as well as using higher levels ofBloom’s taxonomy should be made where engineering ethics education is applied in practice

Chiral properties of SU(3) sextet fermions

SU(3) gauge theory with overlap fermions in the 2-index symmetric (sextet) and fundamental representations is considered. A priori it is not known what the pattern of chiral symmetry breaking is in a higher dimensional representation although the general expectation is that if two representations are both complex, the breaking pattern will be the same. This expectation is verified for the sextet at N_f = 0 in several exact zero mode sectors. It is shown that if the volume is large enough the same random matrix ensemble describes both the sextet and fundamental Dirac eigenvalues. The number of zero modes for the sextet increases approximately 5-fold relative to the fundamental in accordance with the index theorem for small lattice spacing but zero modes which do not correspond to integer topological charge do exist at larger lattice spacings. The zero mode number dependence of the random matrix model predictions correctly match the simulations in each sector and each representation.Comment: 38 pages (12 pages text and gazillion tables/figures), minor modification, references adde

What Powers Lyman alpha Blobs?

Lyman alpha blobs (LABs) are spatially extended lyman alpha nebulae seen at high redshift. The origin of Lyman alpha emission in the LABs is still unclear and under debate. To study their heating mechanism(s), we present Australia Telescope Compact Array (ATCA) observations of the 20 cm radio emission and Herschel PACS and SPIRE measurements of the far-infrared (FIR) emission towards the four LABs in the protocluster J2143-4423 at z=2.38. Among the four LABs, B6 and B7 are detected in the radio with fluxes of 67+/-17 microJy and 77+/-16 microJy, respectively, and B5 is marginally detected at 3 sigma (51+/-16 microJy). For all detected sources, their radio positions are consistent with the central positions of the LABs. B6 and B7 are obviously also detected in the FIR. By fitting the data with different templates, we obtained redshifts of 2.20$^{+0.30}_{-0.35}$ for B6 and 2.20$^{+0.45}_{-0.30}$ for B7 which are consistent with the redshift of the lyman alpha emission within uncertainties, indicating that both FIR sources are likely associated with the LABs. The associated FIR emission in B6 and B7 and high star formation rates strongly favor star formation in galaxies as an important powering source for the lyman alpha emission in both LABs. However, the other two, B1 and B5, are predominantly driven by the active galactic nuclei or other sources of energy still to be specified, but not mainly by star formation. In general, the LABs are powered by quite diverse sources of energy.Comment: 7 pages and 3 figurs, accepted by A&

Homelessness coverage, social reality, and media ownership: Comparing a national newspaper with two regional newspapers in Canada

The media plays an important role in the discourse of homelessness. The purpose of this study was to compare how two Alberta newspapers (Calgary Herald and Edmonton Journal) and one national newspaper(the Globe and Mail) covered homeless issues in terms of population, main themes, article type, monthly differences, and critical time periods. Through purposive sampling technique, 449

Beat Cepheids as Probes of Stellar and Galactic Metallicity

The mere location of a Beat Cepheid model in a Period Ratio vs. Period diagram (Petersen diagram) puts very tight constraints on its metallicity Z. The Beat Cepheid Peterson diagrams are revisited with linear nonadiabatic turbulent convective models, and their accuracy as a probe for stellar metallicity is evaluated. They are shown to be largely independent of the helium content Y, and they are also only weakly dependent on the mass-luminosity relation that is used in their construction. However, they are found to show sensitivity to the relative abundances of the elements that are lumped into the metallicity parameter Z. Rotation is estimated to have but a small effect on the 'pulsation metallicities'. A composite Petersen diagram is presented that allows one to read off upper and lower limits on the metallicity Z from the measured period P0 and period ratio P1/P0.Comment: 9 pages, 12 color figures (black and white version available from 1st author's website). With minor revisions. to appear in Ap

Global parametrization of range image sets

We present a method to globally parameterize a surface represented by height maps over a set of planes (range images). In contrast to other parametrization techniques, we do not start with a manifold mesh. The parametrization we compute defines a manifold structure, it is seamless and globally smooth, can be aligned to geometric features and shows good quality in terms of angle and area preservation, comparable to current parametrization techniques for meshes. Computing such global seamless parametrization makes it possible to perform quad remeshing, texture mapping and texture synthesis and many other types of geometry processing operations. Our approach is based on a formulation of the Poisson equation on a manifold structure defined for the surface by the range images. Construction of such global parametrization requires only a way to project surface data onto a set of planes, and can be applied directly to implicit surfaces, nonmanifold surfaces, very large meshes, and collections of range scans. We demonstrate application of our technique to all these geometry types