28,378 research outputs found
Abuelito
An outsider’s perspective of the Spanish funerary process and the universal grappling with grief
In Defense of Feminists Who Like Fashion
I’m sitting on the downtown R train one night in Manhattan, a copy of Vogue resting on my crossed legs. It is late and I am clearly unwinding peacefully as I thumb through page after glamorous page of my magazine. The train stops at Prince Street and there’s the usual flux of people in and out. Those left inside settle as the train pulls out of the station.
“Ugh. Fashion is stupid,” remarks one young man to another, both of whom are sitting diagonally from me and well within earshot. He’s watching me ignore him as I continue enjoying my reading material. [excerpt
Generating sequences and Poincar\'e series for a finite set of plane divisorial valuations
Let be a finite set of divisorial valuations centered at a 2-dimensional
regular local ring . In this paper we study its structure by means of the
semigroup of values, , and the multi-index graded algebra defined by ,
\gr_V R. We prove that is finitely generated and we compute its minimal
set of generators following the study of reduced curve singularities. Moreover,
we prove a unique decomposition theorem for the elements of the semigroup.
The comparison between valuations in , the approximation of a reduced
plane curve singularity by families of sets of divisorial
valuations, and the relationship between the value semigroup of and the
semigroups of the sets , allow us to obtain the (finite) minimal
generating sequences for as well as for .
We also analyze the structure of the homogeneous components of \gr_V R. The
study of their dimensions allows us to relate the Poincar\'e series for and
for a general curve of . Since the last series coincides with the
Alexander polynomial of the singularity, we can deduce a formula of A'Campo
type for the Poincar\'e series of . Moreover, the Poincar\'e series of
could be seen as the limit of the series of ,
Small-world behavior in a system of mobile elements
We analyze the propagation of activity in a system of mobile automata. A
number r L^d of elements move as random walkers on a lattice of dimension d,
while with a small probability p they can jump to any empty site in the system.
We show that this system behaves as a Dynamic Small-World (DSW) and present
analytic and numerical results for several quantities. Our analysis shows that
the persistence time T* (equivalent to the persistence size L* of small-world
networks) scales as T* ~ (r p)^(-t), with t = 1/(d+1).Comment: To appear in Europhysics Letter
The stellar content of the Local Group dwarf galaxy Phoenix
We present new deep ground-based photometry of the Local Group dwarf
galaxy Phoenix. Our results confirm that this galaxy is mainly dominated by red
stars, with some blue plume stars indicating recent (100 Myr old) star
formation in the central part of the galaxy. We have performed an analysis of
the structural parameters of Phoenix based on an ESO/SRC scanned plate, in
order to search for differentiated component. The results were then used to
obtain the color-magnitude diagrams for three different regions of Phoenix in
order to study the variation of the properties of its stellar population. The
young population located in the central component of Phoenix shows a clear
asymmetry in its distribution, that could indicate a propagation of star
formation across the central component. The HI cloud found at 6 arcmin
Southwest by Young & Lo (1997) could have been involved in this process.
We also find the presence of a substantial intermediate-age population in the
central region of Phoenix that would be less abundant or absent in its outer
regions. This result is also consistent with the gradient found in the number
of horizontal branch stars, whose frequency relative to red giant branch stars
increases towards the outer part of the galaxy. These results, together with
those of our morphological study, suggest the existence of an old, metal-poor
population with a spheroidal distribution surrounding the younger inner
component of Phoenix. This two-component structure may resemble the halo-disk
structure observed in spirals, although more data, in particular on kinematics,
are necessary to confirm this.Comment: 46 pages, 21 figures, 9 Tables, to be published in AJ, August 9
Constraints on the formation mechanism of the planetary mass companion of 2MASS 1207334-393254
In this paper we discuss the nature and the possible formation scenarios of
the companion of the brown dwarf 2MASS 1207334-393254. We initially discuss the
basic physical properties of this object and conclude that, although from its
absolute mass (), it is a planetary object, in terms of its mass
ratio and of its separation with respect to the primary brown dwarf, it
is consistent with the statistical properties of binaries with higher primary
mass. We then explore the possible formation mechanism for this object. We show
that the standard planet formation mechanism of core accretion is far too slow
to form this object within 10 Myr, the observed age of the system. On the other
hand, the alternative mechanism of gravitational instability (proposed both in
the context of planet and of binary formation) may, in principle, work and form
a system with the observed properties.Comment: 5 pages, MNRAS in pres
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