An Experimental Investigation of Alternatives to Expected Utility Using Pricing Data

Experimental research on decision making under risk has until now always employed choice data in order to evaluate the empirical performance of expected utility and the alternative non-expected utility theories. The present paper performs a similar analysis which relies on pricing data instead of choice data. Since pricing data lead in many cases to a different ordering of lotteries than choices (e.g. the preference reversal phenomenon) our analysis may have fundamental different results than preceding investigations. We elicit three different types of pricing data: willingness-to-pay, willingness-to-accept and certainty equivalents under the Becker-DeGroot-Marschak (BDM) incentive mechanism. One of our main result shows that the comparative performance of the single theories differs significantly under these three types of pricing data.experiments

Neutron star cooling in transiently accreting low mass binaries: a new tool for probing nuclear matter

We explore, using an exact cooling code, the thermal evolution of a neutron star undergoing episodes of intense accretion, alternated by long periods of quiescence (e.g. Soft X-Ray Transients). We find that the soft component of the quiescent luminosity of Aql X-1, 4U 1608-522 and of SAX J1808.4-3658 can be understood as thermal emission from a cooling neutron star with negligible neutrino emission. In the case of Cen X-4 strong neutrino emission from the inner core is necessary to explain the observation: this may indicate that the neutron star of Cen X-4 is heavier than 1.4 Msun. This study opens the possibility of using the quiescent emission of Soft X-Ray Transients as a tool for probing the core superfluidity in relation to the mass of the neutron star.Comment: 5 pages, 3 embedded figures, latex style included. To appear in "Evolution of Binary and Multiple Stars", 2001, eds. Ph. Podsiadlowski, S. Rappaport, A. R. King, F. D'Antona & L. Burderi (San Francisco: ASP

Noise and Bias in Eliciting Preferences

In the context of eliciting preferences for decision making under risk, we ask the question: "which might be the 'best' method for eliciting such preferences?". It is well known that different methods differ in terms of the bias in the elicitation; it is rather less well-known that different methods differ in terms of their noisiness. The optimal trade-off depends upon the relative magnitutdes of these two effects. We examine four different elicitation mechanisms (pairwise choice, willingness-to-pay, willingness-to-accept, and certainty equivalents) and estimate both effect. Our results suggest that economists might be better advised to use what appears to be a relatively inefficient elicitation technique (i.e. pairwise choice) in order to avoid trhe bias in better-known and more widely-used techniques.Pairwise choice, willingness-to-pay, willingness-to-accept, errors, noise, biases

The Steep Spectrum Quasar PG1404+226 with ASCA, HST and ROSAT

(abridged) We present and discuss our observations of the NL quasar PG1404+226 with ASCA and HST, and a re-analysis of our earlier observations with ROSAT. The soft X-ray spectrum is very steep and displays an absorption feature (edge or line at ~1.1 keV). We have applied a variety of models to the ASCA and ROSAT spectra without finding a completely satisfactory fit, and the identification of the edge remains uncertain. A satisfactory fit of the ASCA spectrum assuming that the edge is produced by highly ionized iron (using the code absori in XSPEC) is obtained with an overabundance of iron by a factor > 25 compared to solar, a suggestion supported by the extremely high equivalent width of the Fe K_alpha line at 6.4 keV. A warm absorber model fitting the absorption feature with NeVII-NeX edges and assuming a peculiar oxygen/neon abundance ratio is consistent with the ROSAT data but not the ASCA data. Finally, it is also possible that the observed edge is caused by a OVIII or OVII edge or line, blueshifted by z_abs=0.2 to 0.5 depending on the specific identification, as has been suggested previously for 2 other NL quasars, but there are no other features in the UV and X-ray spectra in support of this suggestion. Two systems of UV absorption lines, one nearly at rest in the source frame, the other blueshifted by ~1900 km/s are identified in the HST/FOS spectra. Photoionization models indicate that the UV absorption and the ~1 keV absorption are probably caused by absorbers with different physical conditions. PG1404+226 is one more case of AGN where both UV and X-ray absorption features are detected, thereby increasing further the significance of the previously noted statistical association of the two types of absorbers.Comment: 11 pages, A&A in pres

Recycling neutron stars to ultra short periods: a statistical analysis of their evolution in the mu-P plane

We investigate the statistical evolution of magnetic neutron stars, recycled in binary systems, simulating synthetic populations. To bracket uncertainties, we consider a soft (FP) and a stiff (PS) equation of state (EoS) for nuclear matter and explore the hypothesis that the magnetic field is confined in the stellar crust. We follow the magneto-rotational evolution within a simple recycling scenario, including the possibility of magnetospheric propeller. We find the presence of a tail in the period distribution of the synthetic populations at periods shorter than 1.558 ms, the minimum detected so far. For the soft EoS the recycling gives rise to a spin distribution which is increasing monotonically toward short periods and a clear ``barrier'' forms at the minimum period for the onset of mass shedding. For the stiff EoS the distribution is flatter displaying a broad maximum about 2-4 ms. The estimated fraction of neutron stars spinning close to their shedding limit over the millisecond pulsar population is found to be significant. Crustal magnetic field decay models predict the existence of massive (M>1.4 M_sun) rapidly spinning neutron stars with very low magnetic moment.Comment: 34 pages, 2 tables, 9 figures, Latex. Accepted (5 Jul 99) for publication in the Astrophysical Journal Supplement