58,900 research outputs found
Traces and shards of self-injury: Strange accounting with “Author X”
No full textIn this strange account autoethnography, three or four authors explore their lived experiences with self-injury. Strange accounting is both a post-modern style of text, and a method for keeping identities concealed when risks and secrets are in play. Author X, a post-modern place-keeper for an anonymous author who may or may not have contributed to this manuscript, introduces a new dimension and layer of concealment. With Author X in-play and under erasure, the reader will never be sure if there were three or four authors on this manuscript. Through strange accounting, a post-structuralist/postmodernist frame will be applied to understanding the self-injury experience. We frame self-injury as a social practice and, for some, an everyday norm, while remaining acutely aware of the stigma surrounding the topic of self-injury. Each of us, coupled with Author X, provide the others cover to trace stories of self-injury through the literature, our flesh, and our lives
Prudent choices and rationality
No full textIn this paper, we study the relationships between binary lexicographic composition of rationales (see [Tadenuma, 2002]), prudent choices (see [Houy, 2008a]) and refined prudent choices (see [Houy, 2008b]) in the case of multi-criteria decision making. We show that these relationships are linked to the non-emptiness and rationality properties of these choice functions
Prudent Budgetary Policy: Political Economy of Precautionary Taxation
No full textThe theory of tax smoothing and determination of public debt with uncertain future national income is extended for prudence. A prudent government deliberately underestimates future national income and the tax base, especially if the variance and persistence of shocks hitting the tax base are large and the tax rate and the unemployment benefit are large. As a precaution the tax rate is set higher and the level of public spending lower. As a result, as income and the tax base turn out to be bigger than budgeted, the minister of finance enjoys windfall revenues and is able to gradually reduce debt and debt service over time. This permits, depending on political preferences, either gradual cuts in the tax rate, gradual increases in government spending or a combination of both. It is easy to allow for government assets as well. Finally, political economy justifications are offered of why it is desirable to appoint a strong and pessimistic minister of finance. In particular, we show that prudence is able to offset the intertemporal spending, tax and debt biases resulting from the common-pool distortions. If the minister of finance and the prime minister are given as many voting rights as the spending ministers combined, the intratemporal common-pool distortions of an excessively large public sector are eliminated as well. A strong and pessimistic minister of finance can thus control the impatient profligacy of squabbling spending ministers. However, if voters care about outcomes on election eve, prudence may be abused for short-run electoral gains. Opportunistic manipulation of election results, however, also dampens the intertemporal common-pool distortions.prudence, pessimism, precautionary taxation, tax smoothing, public debt, income forecasts, public sector assets, common pool, feedback Nash, voting rights, electoral budget cycles, political economy
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
A refinement of prudent choices
No full textWe charaterize the choice correspondences that can be rationalized by a procedure that is a refinement of the prudent choices exposed in [Houy, 2008]. Our characterization is made by means of the usual expansion axiom and by a weakening of the usual contraction axiom α
Relations between x-ray timing features and spectral parameters of galactic black hole x-ray binaries
No full textWe present a study of correlations between spectral and timing parameters for a sample of black hole X-ray binary candidates. Data are taken from GX
339-4, H 1743-322, and XTE J1650-500, as the Rossi X-ray Timing Explorer
(RXTE) observed complete outbursts of these sources. In our study we investigate outbursts that happened before the end of 2009 to make use of the high-energy coverage of the HEXTE detector and select observations that
show a certain type of quasi-periodic oscillations (type-C QPOs). The spectral parameters are derived using the empirical convolution model simpl to model the Comptonized component of the emission together with a disc blackbody for the emission of the accretion disc. Additional spectral features, namely a reflection component, a high-energy cut-off, and excess emission at 6.4 keV, are taken into account. Our investigations confirm the known positive
correlation between photon index and centroid frequency of the QPOs and reveal an anti-correlation between the fraction of up-scattered photons and the QPO frequency. We show that both correlations behave as expected in the “sombrero”
geometry. Furthermore, we find that during outburst decay the correlation between photon index and QPO frequency follow a general track, independent of individual outbursts
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Measurement of the Color-Suppressed B0->D(*)0 pi0 /omega/eta/eta Prime Branching Fractions
No full textThe authors report results on the branching fraction (BF) measurement of the color-suppressed decays {bar B}{sup 0} {yields} D{sup 0}{pi}{sup 0}, D*{sup 0}{pi}{sup 0}, D{sup 0}{eta}, D*{sup 0}{eta}, D{sup 0}{omega}, D*{sup 0}{omega}, D{sup 0}{eta}{prime}, and D*{sup 0}{eta}{prime}. They measure the branching fractions BF(D{sup 0}{pi}{sup 0}) = (2.78 {+-} 0.08 {+-} 0.20) x 10{sup -4}, BF(D*{sup 0}{pi}{sup 0}) = (1.78 {+-} 0.13 {+-} 0.23) x 10{sup -4}, BF(D{sup 0}{eta}) = (2.41 {+-} 0.09 {+-} 0.17) x 10{sup -4}, BF(D*{sup 0}{eta}) = (2.32 {+-} 0.13 {+-} 0.22) x 10{sup -4}, BF(D{sup 0}{omega}) = (2.77 {+-} 0.13 {+-} 0.22) x 10{sup -4}, BF(D*{sup 0}{omega}) = (4.44 {+-} 0.23 {+-} 0.61) x 10{sup -4}, BF(D{sup 0}{eta}{prime}) = (1.38 {+-} 0.12 {+-} 0.22) x 10{sup -4} and BF(D*{sup 0}{eta}{prime}) = (1.29 {+-} 0.23 {+-} 0.23) x 10{sup -4}, where the first uncertainty is statistical and the second is systematic. The result is based on a sample of (454 {+-} 5) x 10{sup 6} B{bar B} pairs collected at the {Upsilon}(4S) resonance from 1999 to 2007, with the BABAR detector at the PEP-II storage rings at the Stanford Linear Accelerator Center. The measurements are compared to theoretical predictions by factorization, SCET and pQCD. The presence of final state interactions predictions by factorization, SCET and pQCD. The presence of final state interactions is confirmed and the measurements seem to be more in favor of SCET compared to pQCD
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Enhanced colour encoding of materials discrimination information for multiple view dual-energy x-ray imaging
No full textThis thesis reports an investigation into dual-energy X-ray discrimination techniques. These techniques are designed to provide colour-coded materials discrimination information in a sequence of perspective images exhibiting sequential parallax. The methods developed are combined with a novel 3D imaging technique employing depth from motion or kinetic depth effect (KDE). This technique when applied to X-ray images is termed KDEX imaging and was developed previously by the university team for luggage screening applications at security checkpoints. A primary motivation for this research is that the dual-energy X-ray techniques, which are routinely incorporated into ‘standard’ 2D luggage scanners, provide relatively crude materials discrimination information. In this work it was critical that robust materials discrimination and colour encoding process was implemented as the sequential parallax exhibited by the KDEX imagery may introduce colour changes, due to the different X-ray beam paths associated with each perspective image. Any introduction of ‘colour noise’ into the resultant image sequences could affect the perception of depth and hinder the ongoing assessment of the potential utility of the dual-energy KDEX technique. Two dual-energy discrimination methods have been developed, termed K-II and W-E respectively. Employing the total amount of attenuation measured at each energy level and the weight fraction of layered structures, a combination of the K-II and the W-E techniques enables the computation and extraction of a target objects’ effective atomic number (Zeff) and its surface density (ρS) in the presence of masking layers
Are parasites ''prudent'' in space?
No full textThis is the final version of the article. Available from Wiley via the DOI in this record.There has been a renewed controversy on the processes that determine evolution in spatially structured populations. Recent theoretical and empirical studies have suggested that parasites should be expected to be more ''prudent'' (less harmful and slower transmitting) when infection occurs locally. Using a novel approach based on spatial moment equations, we show that the evolution of parasites in spatially structured host populations is determined by the interplay of genetic and demographic spatial structuring, which in turn depends on the details of the ecological dynamics. This allows a detailed understanding of the roles of epidemiology, demography and network topology. Demographic turnover is needed for local interactions to select for prudence in the susceptible-infected models that have been the focus of previous studies. In diseases with little demographic turnover (as typical of many human diseases), we show that only parasites causing diseases with long-lived immunity are likely to be prudent in space. We further demonstrate why, at intermediate parasite dispersal, virulence can evolve to higher levels than predicted by non-spatial theory.S.L. was supported by a
Marie Curie Intra-European Fellowship FP7-220080 (MOBVIR)
from the Seventh Framework Programme of the
European Commission
Are Canadian pension plans disadvantaged by the current structure of portfolio regulation?
No full textWe investigate the performance of Canadian pension funds relative to those from the UK and US, in the light of the ongoing quantitative asset restrictions that still apply in Canada, compared with the purer prudent person approach in the UK and US. We find that although Canadian funds often obtain better combinations of return and risk, returns are often less than could be obtained given financial market conditions, as shown by dummy portfolios split evenly between bonds and equities, or diversified into real estate, as well as mean-variance optimal portfolios. In contrast, UK and US funds typically outperform such benchmarks. Combined with criticisms of specific Canadian regulations in the light of finance theory and empirical evidence, the paper makes a case for removal of residual quantitative restrictions in Canada, and their replacement by sole prudent person regulations
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