The Brightest Black Holes

I suggest that there are two classes of ultraluminous X-ray sources (ULXs), corresponding to super-Eddington mass inflow in two situations: (a) thermal-timescale mass transfer in high-mass X-ray binaries, and (b) long-lasting transient outbursts in low-mass X-ray binaries. These two classes are exemplified by SS433 and microquasars like GRS 1915+105 respectively. The observed ULX population is a varying mixture of the two, depending on the star formation history of the host galaxy. ULXs in galaxies with vigorous star formation (such as the Antennae) are generally SS433--like, while ULXs in elliptical galaxies must be of the microquasar type. The latter probably have significantly anisotropic radiation patterns. They should also be variable, but demonstrating this may require observations over decades. The close analogy between models of X-ray binaries and active galactic nuclei (AGN) suggests that there should exist an apparently super-Eddington class of the latter, which may be the ultrasoft AGN, and a set of X-ray binaries with Doppler--boosted X-ray emission. These are presumably a subset of the ULXs, but remain as yet unidentified.Comment: 4 pages, no figures; accepted for MNRAS Letter

Thinking in Chinese vs. Thinking in English: Social Preference and Risk Attitudes of Multicultural Minds

This paper investigates whether language priming activates different cultural identities and norms associated with the language communicated with respect to social preference and risk attitudes. Our contribution is on identifying the conditions where there will be language priming effects. We conduct economic games with bilingual subjects using Chinese and English as instructions. It is found that language priming affects social preference, but only in context involving strategic interactions. In social preference games involving strategic interactions, e.g., the trust game, subjects in the Chinese treatment are more trusting and trustworthy. In individual choice games, such as the dictator game, there is no treatment difference. Further, we also find that language priming affects risk attitudes. Subjects in the Chinese treatment prefer to pick Chinese lucky numbers in Mark Six lottery. These findings suggest that the effect of language priming is context dependent.language, bilingual, biculture, social preference, risk attitudes

Low Scale Technicolour at LEP

We discuss the phenomenology of an $SU(2)_{TC}$ technicolour model with a low technicolour confinement scale ${\Lambda}_{TC} \sim 50-100 GeV$. Such a low technicolour scale may give rise to the first hints of technicolour being seen at LEPI and spectacular technicolour signals at LEPII.Comment: 12 pages+1 figure (available by post), Latex, SHEP92/93-2

Indecent Disclosure

Examines shortfalls in states' public reporting requirements on independent expenditures -- spending not coordinated with candidates -- and presents an example of a loophole that hides contributors. Outlines principles of effective disclosure

Cooling Global Warming Through Transit

For generations, cars have been cool because they are perceived to correlate to independence and wealth. People’s attachment to their cars is one of the most cited examples of why government doesn’t want to invest in mass transit. Accompanying this ideology is an underlying fear and distaste for buses. Recently, Cleveland purposely avoided such a stigma in naming its new bus line “The Health Line” and referring to it always as rapid transit. Yet, providing “cool” features to buses, like making them hybrid or dressing them up like quaint trolleys, has been largely unsuccessful in overhauling the image of buses. Buses aren’t cool. Yet

Effects of Grain Boundary Disorder on Yield Strength

It was recently reported that segregation of Zr to grain boundaries (GB) in nanocrystalline Cu can lead to the formation of disordered intergranular films [1,2]. In this study we employ atomistic computer simulations to study how the formation of these films affects the dislocation nucleation from the GBs. We found that full disorder of the grain boundary structure leads to the suppression of dislocation emission and significant increase of the yield stress. Depending on the solute concentration and heat-treatment, however, a partial disorder may also occur and this aids dislocation nucleation rather than suppressing it, resulting in elimination of the strengthening effect