Radio galaxies - the TeV challenge

Over the past decade, our knowledge of the \gamma-ray sky has been revolutionized by ground- and space-based observatories by detecting photons up to several hundreds of tera-electron volt (TeV) energies. A major population of the $\gamma$-ray bright objects are active galactic nuclei (AGN) with their relativistic jets pointed along our line-of-sight. Gamma-ray emission is also detected from nearby mis-aligned AGN such as radio galaxies. While the TeV-detected radio galaxies (TeVRad) only form a small fraction of the \gamma-ray detected AGN, their multi-wavelength study offers a unique opportunity to probe and pinpoint the high-energy emission processes and sites. Even in the absence of substantial Doppler beaming TeVRad are extremely bright objects in the TeV sky (luminosities detected up to 10^{45} erg/s), and exhibit flux variations on timescales shorter than the event-horizon scales (flux doubling timescale less than 5 minutes). Thanks to the recent advancement in the imaging capabilities of high-resolution radio interferometry (millimeter very long baseline interferometry, mm-VLBI), one can probe the scales down to less than 10 gravitational radii in TeVRad, making it possible not only to test jet launching models but also to pinpoint the high-energy emission sites and to unravel the emission mechanisms. This review provides an overview of the high-energy observations of TeVRad with a focus on the emitting sites and radiation processes. Some recent approaches in simulations are also sketched. Observations by the near-future facilities like Cherenkov Telescope Array, short millimeter-VLBI, and high-energy polarimetry instruments will be crucial for discriminating the competing high-energy emission models.Comment: Invited review article, submitted to Galaxies; 28 pages, 8 figure

An examination of the mediating role of salt knowledge and beliefs on the relationship between socio-demographic factors and discretionary salt use: a cross-sectional study

Background Discretionary salt use varies according to socio-demographic factors. However, it is unknown whether salt knowledge and beliefs mediate this relationship. This study examined the direct and indirect effect of socio-demographic factors on salt knowledge and discretionary salt use in a sample of 530 Australian adults.Methods An internet based cross-sectional survey was used to collect data for this study. Participants completed an online questionnaire which assessed their salt knowledge, beliefs and salt use behaviour. Mplus was used to conduct structural equation modelling to estimate direct and indirect effects.Results The mean age of the participants was 49.2 years, and about a third had tertiary education. Discretionary salt use was inversely related to age (r=-0.11; p&lt;0.05), and declarative salt knowledge (knowledge of factual information) scores (r = -0.17; p&lt;0.01), but was positively correlated with misconceptions about salt (r = 0.09; p&lt;0.05) and beliefs about the taste of salt (r = 0.51; p&lt;0.001). Structural equation modelling showed age, education and gender were indirectly associated with the use of discretionary salt through three mediating pathways; declarative salt knowledge, misconceptions about salt and salt taste beliefs.Conclusions Inequalities observed between socio-demographic groups in their use of discretionary salt use can potentially be reduced through targeted salt knowledge and awareness campaigns.<br /

Using new literatures as a resource in fostering cross cultural awareness

This paper is based on the premise that the wealth of new literatures in English that are available in several countries of Asia and South East Asia today can serve not only to provide students access to the rich and varied cultural life of the people in these settings, but also help develop in them sensitivity and empathy towards other cultures. Given that English no longer belongs to any one nation or culture, and is increasingly being used in numerous multilingual and multicultural settings worldwide, it is fast becoming ‘re-nationalised’ (McKay 2000), as it takes on new cultural associations, experiences and values. In teaching English as an international language (EIL), therefore, it no longer makes sense to place an exclusive focus on target culture knowledge alone. The paper makes a strong case for including other cultural materials, especially those from Asian and South East Asian literature, in the selection of content and topics for textbooks constructed for use in EFL/ESL contexts, with a particular focus on fostering cross-cultural tolerance and understanding, a neglected area in ELT. Further, the paper goes on to illustrate how texts from these new literatures may be used in promoting cross-cultural understanding in the language classroom. Only recently has cross–cultural understanding begun to receive the kind of attention it deserves in the realm of EFL and ESL teaching/learning. Indeed, for a long time culture itself was considered peripheral, or at best, no more than a supplementary diversion (Tseng, 2002) to the teaching and learning of language, although cross-cultural variation has continued to be a live and productive topic of study in sociolinguistic and pragmatic research. Even where cultural aspects of language study have been addressed in EFL/ESL, traditionally this has pertained exclusively to target language culture. Given the insight that language and culture are inseparable, and that therefore, to teach language is to teach culture,the belief prevailed that in order to gain full competence in the language learners of English in different parts of the world need to internalize the cultural norms of native speakers of English – that is, speakers of English from the Inner Circle (Kachru, 1989) or BANA (namely, British, Australasian and North American) countries (Holliday, 1994)

Process Matters: Specialization in Federal Appellate Review of Noncapital Section 2254 Cases

This Note assesses the need for specialized review in the federal circuit courts of noncapital habeas cases brought by state prisoners under 28 U.S.C. § 2254. It first argues that the complexity of federal habeas law, the substantial disuniformity between circuits, the conflicting visions proffered by the Warren Court’s habeas jurisprudence and Congress’s recent statutory enactments—together with the greatest stakes possible at issue, liberty—are all factors warranting the creation of a national court of appeals that would hear only habeas cases. Recognizing, however, that creating such a court is a low priority for Congress at best and simply unfeasible at worst, this Note also makes another recommendation for injecting specialized review into appellate adjudication. Specifically, the circuit courts’ use of line staff attorneys to screen petitions can be much improved by creating a career staff attorney position dedicated solely to review of noncapital § 2254 cases. A formal position will attract better candidates, have lower rates of turnover, and concentrate experience and expertise to the benefit of judges and litigants

Evidence based or person centered? An ontological debate

Evidence based medicine (EBM) is under critical debate, and person centered healthcare (PCH) has been proposed as an improvement. But is PCH offered as a supplement or as a replacement of EBM? Prima facie PCH only concerns the practice of medicine, while the contended features of EBM also include methods and medical model. I here argue that there are good philosophical reasons to see PCH as a radical alternative to the existing medical paradigm of EBM, since the two seem committed to conflicting ontologies. This paper aims to make explicit some of the most fundamental assumptions that motivate EBM and PCH, respectively, in order to show that the choice between them ultimately comes down to ontological preference. While EBM has a solid foundation in positivism, or what I here call Humeanism, PCH is more consistent with causal dispositionalism. I conclude that if there is a paradigmatic revolution on the way in medicine, it is first of all one of ontology

Constrained Monotone Function Maximization and the Supermodular Degree

The problem of maximizing a constrained monotone set function has many practical applications and generalizes many combinatorial problems. Unfortunately, it is generally not possible to maximize a monotone set function up to an acceptable approximation ratio, even subject to simple constraints. One highly studied approach to cope with this hardness is to restrict the set function. An outstanding disadvantage of imposing such a restriction on the set function is that no result is implied for set functions deviating from the restriction, even slightly. A more flexible approach, studied by Feige and Izsak, is to design an approximation algorithm whose approximation ratio depends on the complexity of the instance, as measured by some complexity measure. Specifically, they introduced a complexity measure called supermodular degree, measuring deviation from submodularity, and designed an algorithm for the welfare maximization problem with an approximation ratio that depends on this measure. In this work, we give the first (to the best of our knowledge) algorithm for maximizing an arbitrary monotone set function, subject to a k-extendible system. This class of constraints captures, for example, the intersection of k-matroids (note that a single matroid constraint is sufficient to capture the welfare maximization problem). Our approximation ratio deteriorates gracefully with the complexity of the set function and k. Our work can be seen as generalizing both the classic result of Fisher, Nemhauser and Wolsey, for maximizing a submodular set function subject to a k-extendible system, and the result of Feige and Izsak for the welfare maximization problem. Moreover, when our algorithm is applied to each one of these simpler cases, it obtains the same approximation ratio as of the respective original work.Comment: 23 page