Testing of a spacecraft model in a combined environment simulator

A scale model of a satellite was tested in a large vacuum facility under electron bombardment and vacuum ultraviolet radiation to investigate the charging of dielectric materials on curved surfaces. The model was tested both stationary and rotating relative to the electron sources as well as grounded through one megohm and floating relative to the chamber. Surface potential measurements are presented and compared with the predictions of computer modelling of the stationary tests. Discharge activity observed during the stationary tests is discussed and signals from sensing devices located inside and outside of the model are presented

The equity premium puzzle and decreasing relative risk aversion

Agents are assumed to have a power risk aversion utility function in an otherwise standard asset pricing model. These preferences are shown to be capable of eliminating one version of the equity premium and risk free rate puzzles when they display decreasing relative risk aversion.asset pricing,equity premium,risk aversion

Irish House Prices - Will the Roof Cave In?

In the last few years there have been many comments made in the media about the Irish housing market boom. This paper focuses on two of these comments. The first comment is that some economists have suggested that a speculative bubble might be present in Irish house prices. The second comment is that some housing market analysts have asked whether a crash similar to what happened in the British housing market in the late 1980s would occur in Ireland. Many of these analysts suggest that it is highly unlikely that a similar slump would occur in the Irish housing market. Given that bubbles have a habit of bursting one might think that these remarks are contradictory. We reconcile these two comments using regime-switching models of real secondhand house prices in Britain and Ireland. The models are estimated and tested to explore whether speculative bubbles, fads or just fundamentals drive house prices. Our main findings suggest that there was a speculative bubble in Britain in the late 1980s and in Ireland in the late 1990s. We estimate that the probability of a crash in Britain reached its highest value of about 5 per cent in the last few quarters of 1989. We also estimate the probability of a crash in the Irish housing market to have increased to around 2 per cent by the end of 1998.

The relationship between noise and annoyance around Orly

The extent to which annoyance estimated by an isopsophic index is a good forecaster for annoyance perceived near airport approaches was investigated. An index of sensed annoyance is constructed, and the relationship between the annoyance index and the isopsophic index is studied

Solving Exchange Rate Puzzles with neither Sticky Prices nor Trade Costs

We present a simple framework in which both the exchange rates disconnect and forward bias puzzles are simultaneously resolved. The flexible-price two-country monetary model is extended to include a consumption externality with habit persistence. Habit persistence is modeled using Campbell Cochrane preferences with ‘deep’ habits. By deep habits, we mean habits defined over goods rather than countries. The model is simulated using the artificial economy methodology. It offers a neo-classical explanation of the Meese-Rogoff puzzle and mimics the failure of fundamentals to explain nominal exchange rates in a linear setting. Finally, the model naturally generates the negative slope in the standard forward market regression.Exchange Rate Puzzles; Forward Foreign Exchange; Habit Persistence

NASCAP modelling of environmental-charging-induced discharges in satellites

The charging and discharging characteristics of a typical geosynchronous satellite experiencing time-varying geomagnetic substorms, in sunlight, were studied utilizing the NASA Charging Analyzer Program (NASCAP). An electric field criteria of 150,000 volts/cm to initiate discharges and transfer of 67 percent of the stored charge was used based on ground test results. The substorm characteristics were arbitrarily chosen to evaluate effects of electron temperature and particle density (which is equivalent to current density). It was found that while there is a minimum electron temperature for discharges to occur, the rate of discharges is dependent on particle density and duration times of the encounter. Hence, it is important to define the temporal variations in the substorm environments

Solving Exchange Rate Puzzles with neither Sticky Prices nor Trade Costs

We present a simple framework in which both the exchange rates disconnect and forward bias puzzles are simultaneously resolved. The flexible-price two-country monetary model is extended to include a consumption externality with habit persistence. Habit persistence is modeled using Campbell Cochrane preferences with deep? habits. By deep habits, we mean habits defined over goods rather than countries. The model is simulated using the artificial economy methodology. It offers a neo-classical explanation of the Meese-Rogoff puzzle and mimics the failure of fundamentals to explain nominal exchange rates in a linear setting. Finally, the model naturally generates the negative slope in the standard forward market regression.Exchange Rate Puzzles; Forward Foreign Exchange; Habit Persistence

For Rich or for Poor: When does Uncovered Interest Parity Hold?

We present a model that simultaneously explains why uncovered interest parity holds for some pairs of countries and not for others. The flexible-price two-country monetary model is extended to include a consumption externality with habit persistence. Habit persistence is modeled using Campbell Cochrane preferences with ‘deep’ habits along the lines of the work of Ravn, Schmitt-Grohe and Uribe. By deep habits, we mean habits defined over goods rather than countries. The negative slope in the Fama regression arises when monetary instability is low and the precautionary savings motive dominates the intertemporal substitution motive. When monetary instability is high, the Fama slope is positive in line with uncovered interest parity. The model is simulated using the artificial economy methodology for 34 currencies against the US dollar. We conclude that, given the predominance of precautionary savings, the degree of monetary instability explains whether or not uncovered interest parity holds.Monetary instability; Uncovered interest parity; Forward biasedness puzzle; Carry trade; Habit persistence

The Be/X-ray Transient V0332+53: Evidence for a tilt between the orbit and the equatorial plane?

We present optical and infrared observations of BQ Cam, the optical counterpart to the Be/X-ray transient system V0332+53. BQ Cam is shown to be an O8-9Ve star, which places V0332+53 at a distance of ~7 kpc. H-alpha spectroscopy and infrared photometry are used to discuss the evolution of the circumstellar envelope. Due to the low inclination of the system, parameters are strongly constrained. We find strong evidence for a tilt of the orbital plane with respect to the circumstellar disc (pressumably on the equatorial plane). Even though the periastron distance is only ~ 10 R_*, during the present quiescent state the circumstellar disc does not extend to the distance of periastron passage. Under these conditions, X-ray emission is effectively prevented by centrifugal inhibition of accretion. The circumstellar disc is shown to be optically dense at optical and infrared wavelengths, which together with its small size, is taken as an indication of tidal truncation.Comment: 9 pages, 3 figures, uses mn.sty and epsfig Accepted for publication in MNRA

Getting a Helping Hand: Parental Transfers and First-Time Homebuyers

A model that allows for inter vivos intergenerational transfers in a booming housing market is developed. The model is used to explain how transfers effect the first-time homebuyer’s consumption and housing decisions by alleviating borrowing constraints. The general implications of the model are tested using data from the leading Irish mortgage provider. We find that private transfers are targeted towards homebuyers that are liquidity constrained.Transfers, Housing, Borrowing Constraint