476 research outputs found

    The Effect of the Tax Reform Act of 1986 on the Location of Assets in Financial Services Firms

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    This paper examines the effects of the Tax Reform Act of 1986 on the international location decisions of U.S. financial services firms. The Act included rule changes that made it substantially more difficult for U.S. firms to defer U.S. taxes on overseas financial services income held in low-tax jurisdictions. These same rule changes were not applied to other forms of income; in particular, income generated from active manufacturing operations was still eligible for deferral after the Act. We use information from the tax returns of U.S. corporations to examine how local taxes affect the allocation of assets held abroad. We find that, before the Act, the location of assets in financial subsidiaries was responsive to differences in host country tax rates across jurisdictions. However, after the Act, differences in host country tax rates no longer explain the distribution of assets held in financial services subsidiaries abroad. In contrast, we find that assets held in manufacturing subsidiaries have become more sensitive to variations in tax rates. Our results suggest that the tightening of the anti-deferral provisions applicable to financial services companies has been successful in neutralizing the effect of host country income taxes on investment location decisions.

    Microlensing and the Search for Extraterrestrial Life

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    Are microlensing searches likely to discover planets that harbor life? Given our present state of knowledge, this is a difficult question to answer. We therefore begin by asking a more narrowly focused question: are conditions on planets discovered via microlensing likely to be similar to those we experience on Earth? In this paper I link the microlensing observations to the well-known "Goldilocks Problem" (conditions on the Earth-like planets need to be "just right"), to find that Earth-like planets discovered via microlensing are likely to be orbiting stars more luminous than the sun. This means that light from the planetary system's central star may contribute a significant fraction of the baseline flux relative to the star that is lensed. Such blending of light from the lens with light from the lensed source can, in principle, limit our ability to detect these events. This turns out not to be a significant problem, however. A second consequence of blending is the opportunity to determine the spectral type of the lensed spectral type of the lensed star. This circumstance, plus the possibility that finite-source-size effects are important, implies that some meaningful follow-up observations are likely to be possible for a subset Earth-like planets discovered via microlensing. In addition, calculations indicate that reasonable requirements on the planet's density and surface gravity imply that the mass of Earth-like planets is likely to be within a factor of ∌15\sim 15 of an Earth mass.Comment: 15 pages, 2 figures. To be published in the Astrophysical Journa

    Inter-decadal climate variability in the Southern Hemisphere: evidence from Tasmanian tree rings over the past three millennia

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    EXTRACT (SEE PDF FOR FULL ABSTRACT): The characterization of inter-decadal climate variability in the Southern Hemisphere is severely constrained by the shortness of the instrumental climate records. To help relieve this constraint, we have developed and analyzed a reconstruction of warm-season (November-April) temperatures from Tasmanian tree rings that now extends back to 800 BC. A detailed analysis of this reconstruction in the time and frequency domains indicates that much of the inter-decadal variability is principally confined to four frequency bands with mean periods of 31, 57, 77, and 200 years. ... In so doing, we show how a future greenhouse warming signal over Tasmania could be masked by these natural oscillations unless they are taken into account

    A New Channel for the Detection of Planetary Systems Through Microlensing: II. Repeating Events

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    In the companion paper we began the task of systematically studying the detection of planets in wide orbits (a>1.5REa > 1.5 R_E) via microlensing surveys. In this paper we continue, focusing on repeating events. We find that, if all planetary systems are similar to our own Solar System, reasonable extensions of the present observing strategies would allow us to detect 3-6 repeating events per year along the direction to the Bulge. Indeed, if planetary systems with multiple planets are common, then future monitoring programs which lead to the discovery of thousands of stellar-lens events will likely discover events in which several different planets within a single system serve as lenses, with light curves exhibiting multiple repetitions. In this paper we discuss observing strategies to maximize the discovery of all wide-orbit planet-lens events. We also compare the likely detection rates of planets in wide orbits to those of planets located in the zone for resonant lensing. We find that, depending on the values of the planet masses and stellar radii of the lensed sources (which determine whether or not finite source size is important), and also on the sensitivity of the photometry used by observers, the detection of planets in wide orbits may be the primary route to the discovery of planets via microlensing. We also discuss how the combination of resonant and wide-orbit events can help us to learn about the distribution of planetary system properties (S 6.1). In addition, by determining the fraction of short-duration events due to planets, we indirectly derive information about the fraction of all short-duration events that may be due to low-mass MACHOs (S 6.2).Comment: 51 pages, 7 figures. To be published in the Astrophysical Journal, 20 February 1999. This completes the introduction to the discovery of planets in wide orbits begun in astro-ph/9808075, also to appear in ApJ on 20 February 199

    "Hearts of Flesh:" Collective Identity and the Body in the Book of Ezekiel

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    The book of Ezekiel bears witness to one of the most critical periods for Judean identity formation: the sixth-century BCE forced migrations to Babylonia. It contains an ideology of collective identity which sets the Judean forced migrants apart from the foreign nations surrounding them as well as from the Judeans who remained in Judah. Previous scholarship has tended to emphasize the rhetorical context of one or the other of these outside groups instead of recognizing the significance of both. Meanwhile, social scientific research into collective identities has shown that they are continually reproduced through social interactions in the material world. Individual bodies are the primary sites of identity expression through activities such as bodily modifications, speech, and other behaviours. An ideology of collective identity outlined in a text must have the capacity to be enacted through the body if it is to be effective. This material aspect of ideology is rarely acknowledged in biblical studies, and the book of Ezekiel is no exception. Therefore, the current project addresses Ezekiel’s approach to the collective identity of the forced migrant Judeans in relation to all proximate external groups, paying especial attention to the way he utilizes bodily symbols of identity. Examining Ezekiel’s ideology in this way reveals that he seeks to construct the boundaries of his community by “othering” the practices of foreigners and of the Judeans remaining in Judah. By evoking practices connected with the body in particular, Ezekiel creates an impression of bodies which are inherently different from those of his designated in-group. In so doing, he forms a new ethnic identity for the forced migrant Judeans. Additionally, by describing bodily practices within his own community, Ezekiel reveals his idealized structure of society in terms of gender stratification and religious hierarchy. Studying the bodily practices mentioned in the book of Ezekiel helps to explain not only the writer’s ideology of group identity but also why it was evidently effective, given the survival of a distinct Judean community in Babylonia. These discoveries contribute to both a synchronic and diachronic understanding of some of the key developments in Judean collective identity

    Chandra Studies of the X-ray Point Source Luminosity Functions of M31

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    Three different M31 disk fields, spanning a range of stellar populations, were observed by Chandra. We report the X-ray point source luminosity function (LF) of each region, and the LF of M31's globular clusters, and compare these with each other and with the LF of the galaxy's bulge. To interpret the results we also consider tracers of the stellar population, such as OB associations and supernova remnants. We find differences in the LFs among the fields, but cannot definitively relate them to the stellar content of the fields. We find that stellar population information, average and maximum source luminosities, X-ray source densities, and slopes of the LF are useful in combination.Comment: 7 pages, 3 figures, accepted for publication in ApJ. Higher-resolution figures available on reques

    The impact of psychological stress and trauma on later-life cognitive function and dementia

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    Dementia is an increasing global issue, currently affecting an estimated 50 million people worldwide. This number is predicted to increase to 82 million by the year 2030, due to the ageing global population. Theoretically, preventing late-onset dementia may seem extremely difficult as the greatest risk factor, age, is unmodifiable. However, it is estimated that a third of dementia cases could potentially be prevented or delayed by removing or reducing modifiable risk factors. Increasing evidence suggests that chronic stress, which may ari

    A New Channel for the Detection of Planetary Systems Through Microlensing: I. Isolated Events Due to Planet Lenses

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    We propose and evaluate the feasibility of a new strategy to search for planets via microlensing. This new strategy is designed to detect planets in "wide" orbits, i.e., with orbital separation, aa greater than ∌1.5RE\sim 1.5 R_E. Planets in wide orbits may provide the dominant channel for the microlensing discovery of planets, particularly low-mass (e.g., Earth-mass) planets. This paper concentrates on events in which a single planet serves as a lens, leading to an isolated event of short duration. We point out that a distribution of events due to lensing by stars with wide-orbit planets is necessarily accompanied by a distribution of shorter- duration events. The fraction of events in the latter distribution is proportional to the average value of q\sqrt{q}, where qq is the ratio between \pl and stellar masses. The position of the peak or peaks also provides a measure of the mass ratios typical of planetary systems. We study detection strategies that can optimize our ability to discover isolated short-duration events due to lensing by planets, and find that monitoring employing sensitive photometry is particularly useful. If planetary systems similar to our own are common, even modest changes in detection strategy should lead to the discovery of a few isolated events of short duration every year. We therefore also address the issue of the contamination due to stellar populations of any microlensing signal due to low-mass MACHOs. We describe how, even for isolated events of short duration, it will be possible to test the hypothesis that the lens was a planet instead of a low-mass MACHO, if the central star of the planetary system contributes a measurable fraction of the baseline flux.Comment: 37 pages, 6 figure. To be published in the Astrophysical Journal. This is part one of a series of papers on microlensing by planetary systems containing wide-orbit planets; the series represents a reorganization and extension of astro-ph/971101
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