31,199 research outputs found
Color-Magnitude Diagram Constraints on the Metallicities, Ages, and Star Formation History of the Stellar Populations in the Carina Dwarf Spheroidal Galaxy
Victoria-Regina isochrones for [alpha/Fe] and a wide
range in [Fe/H], along with complementary zero-age horizontal branch (ZAHB)
loci, have been applied to the color-magnitude diagram (CMD) of Carina. The
color transformations that we have used have been "calibrated" so that
isochrones provide excellent fits to the -diagrams of M3 and
M92, when well supported estimates of the globular cluster (GC) reddenings and
metallicities are assumed. The adopted distance moduli, for both the GCs and
Carina, are based on our ZAHB models, which are able to reproduce the old HB
component (as well as the luminosity of the HB clump) of the dwarf spheroidal
galaxy quite well --- even if it spans a range in [Fe/H] of ~ 1.5 dex, provided
that [alpha/Fe] varies with [Fe/H] in approximately the way that has been
derived spectroscopically. Ages derived here agree reasonably well with those
found previously for the old and intermediate-age turnoff stars, as well as for
the period of negligible star formation (SF) activity (~ 6-10 Gyr ago). CMD
simulations have been carried out for the faintest turnoff and subgiant stars.
They indicate a clear preference for SF that lasted several Gyr instead of a
short burst, with some indication that ages decrease with increasing [Fe/H]. In
general, stellar models that assume spectroscopic metallicities provide
satisfactory fits to the observations, including the thin giant branch of
Carina, though higher oxygen abundances than those implied by the adopted
values of [alpha/Fe] would have favorable consequences.Comment: 15 pages, including 12 figures; accepted for publication in the
Astrophysical Journa
THE IMPACT OF ELIMINATION OF THE U.S. ORANGE JUICE TARIFF ON THE MARKET FOR PROCESSED ORANGE PRODUCTS
International Relations/Trade,
Annuities and Individual Welfare
This paper advances the theory of annuity demand. First, we derive sufficient conditions under which complete annuitization is optimal, showing that this well-known result holds true in a more general setting than in Yaari (1965). Specifically, when markets are complete, sufficient conditions need not impose exponential discounting, intertemporal separability or the expected utility axioms; nor need annuities be actuarially fair, nor longevity risk be the only source of consumption uncertainty. All that is required is that consumers have no bequest motive and that annuities pay a rate of return for survivors greater than those of otherwise matching conventional assets, net of administrative costs. Second, we show that full annuitization may not be optimal when markets are incomplete. Some annuitization is optimal as long as conventional asset markets are complete. The incompleteness of markets can lead to zero annuitization but the conditions on both annuity and bond markets are stringent. Third, we extend the simulation literature that calculates the utility gains from annuitization by considering consumers whose utility depends both on present consumption and a which they have become accustomed. The value of annuitization hinges critically on the size of the initial standard-of-living relative to wealth.
Democratizing the American Dream: The Role of a Regional Housing Legislature in the Production of Affordable Housing
Economic, ethnic and racial residential segregation are ubiquitous across United States metropolitan regions. As a result, the majority of affordable housing is located in central cities or inner-ring suburbs, generally in areas of highly concentrated poverty. Outer suburbs are often exempt from providing significant housing for the economically disadvantaged regional citizens. This should not be. If housing policy in metropolitan regions were established in a democratic fashion, the give-and-take of the political process would create strong incentives for regional cooperation in the creation of affordable housing. Drawing together scholarship in the fields of local government law, administrative law, and housing policy, this Note proposes the creation of a Regional Housing Legislature (RHL), a democratically elected body composed of representatives from each of the region\u27s localities, charged with establishing a coherent regional affordable housing policy. The existence of the RHL will diminish the contentiousness of existing affordable housing solutions by providing democratic legitimacy and by giving each locality a meaningful voice in the development of regional affordable housing policy
Simultaneous measurement of multiple parameters of a subwavelength structure based on the weak value formalism
A mathematical extension of the weak value formalism to the simultaneous
measurement of multiple parameters is presented in the context of an optical
focused vector beam scatterometry experiment. In this example, preselection and
postselection are achieved via spatially-varying polarization control, which
can be tailored to optimize the sensitivity to parameter variations. Initial
experiments for the two-parameter case demonstrate that this method can be used
to measure physical parameters with resolutions at least 1000 times smaller
than the wavelength of illumination
Trumpet slices of the Schwarzschild-Tangherlini spacetime
We study families of time-independent maximal and 1+log foliations of the
Schwarzschild-Tangherlini spacetime, the spherically-symmetric vacuum black
hole solution in D spacetime dimensions, for D >= 4. We identify special
members of these families for which the spatial slices display a trumpet
geometry. Using a generalization of the 1+log slicing condition that is
parametrized by a constant n we recover the results of Nakao, Abe, Yoshino and
Shibata in the limit of maximal slicing. We also construct a numerical code
that evolves the BSSN equations for D=5 in spherical symmetry using
moving-puncture coordinates, and demonstrate that these simulations settle down
to the trumpet solutions.Comment: 11 pages, 6 figures, submitted to PR
Near Infrared Surface Properties of the Two Intrinsically Brightest Minor Planets (90377) Sedna and (90482) Orcus
We present low resolution K band spectra taken at the Gemini 8 meter
telescope of (90377) Sedna and (90482) Orcus (provisional designations 2003
VB12 and 2004 DW, respectively), currently the two minor planets with the
greatest absolute magnitudes (i.e. the two most reflective minor planets). We
place crude limits on the surface composition of these two bodies using a Hapke
model for a wide variety of assumed albedos. The unusual minor planet (90377)
Sedna was discovered on November 14, 2003 UT at roughly 90 AU with 1.6 times
the heliocentric distance and perihelion distance of any other bound minor
planet. It is the first solar system object discovered between the Kuiper Belt
and the Oort Cloud, and may represent a transition population between the two.
The reflectance spectrum of (90377) Sedna appears largely featureless at the
current signal-to-noise ratio, suggesting a surface likely to be highly
processed by cosmic rays. For large grain models (100 micron to 1 cm) we find
that (90377) Sedna must have less than 70% surface fraction of water ice and
less than 60% surface fraction of methane ice to 3 sigma confidence. Minor
planet (90482) Orcus shows strong water ice absorption corresponding to less
than 50% surface fraction for grain models 25 micron and larger. Orcus cannot
have more than 30% of its surface covered by large (100 mm to 1 cm) methane
grains to 3 sigma confidence.Comment: Accepted for publication in the Astrophysical Journa
Forced Abortions and Involuntary Sterlization in China: Are the Victims of Coercive Population Control Measures Eligible for Asylum in the United States
This article discusses the propriety of granting political control policy. It argues that China is persecuting some of its citizens through its population control policy and that the United States should grant asylum to those who have been persecuted or who have a genuine fear of future persecution
Alien Registration- Brown, Thomas S A. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/23889/thumbnail.jp
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