476 research outputs found
The Effect of the Tax Reform Act of 1986 on the Location of Assets in Financial Services Firms
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
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 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
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
In the companion paper we began the task of systematically studying the
detection of planets in wide orbits () 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
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 Ezekielâs 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 Ezekielâs ideology in this way reveals that he seeks to construct the boundaries of his community by âotheringâ 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 writerâs 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
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
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
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, greater than .
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
, where 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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Recent Increases in Tasmanian Huon Pine Ring Widths from a Subalpine Stand: Natural Climate Variability, CO2 Fertilisation, or Greenhouse Warming?
Tasmanian subalpine Huon pines from the extreme high-altitude limit of the species distribution provide a summer temperature reconstruction extending back beyond 800 Be. Compared to low elevation Huon pine sites, the subalpine ring-widths exhibit a straightforward direct response to current growth-season temperatures and indicate anomalous warming of 0.33 ± O.06°C from 1967- 91. This warming is consistent with Tasmanian instrumental records and with hemispheric and global records.
The possibility that the trees are responding directly to CO2 fertilisation is explored, using a high-precision record of CO2, obtained from air in Antarctic ice and firn, plus direct measurements of air from Cape Grim. The temperature forcing appears capable of explaining the ring-width variations in the alpine trees over the full range of observed periods, whereas CO2 fertilisation would require a more complex interaction and is not supported by other arguments.
Two millennia-long tree-ring reconstructions of summer temperatures from South America do not exhibit the recent warming, nor other features found in the Tasmanian record on decadal to century time-scales. In fact, the South American chronologies bear little resemblance to each other, but do, however, reflect their own regional instrumental records. The Mt Read ring-width chronology, and the instrumental temperature series used for its calibration, also co-vary with climate influences of a distinctly regional character, yet still replicate many of the features reported as hemispheric and global temperatures over the last century.
Spectral analysis of the Mt Read tree-ring data over the full 2,792 years suggests that at least part of the recent warming in the instrumental records could be a consequence of "natural forcing" of the record, complicating an interpretation in terms of a greenhouse-forced warming
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