11,077 research outputs found
Measuring the transition to homogeneity with photometric redshift surveys
We study the possibility of detecting the transition to homogeneity using
photometric redshift catalogs. Our method is based on measuring the fractality
of the projected galaxy distribution, using angular distances, and relies only
on observable quantites. It thus provides a way to test the Cosmological
Principle in a model-independent unbiased way. We have tested our method on
different synthetic inhomogeneous catalogs, and shown that it is capable of
discriminating some fractal models with relatively large fractal dimensions, in
spite of the loss of information due to the radial projection. We have also
studied the influence of the redshift bin width, photometric redshift errors,
bias, non-linear clustering, and surveyed area, on the angular homogeneity
index H2 ({\theta}) in a {\Lambda}CDM cosmology. The level to which an upcoming
galaxy survey will be able to constrain the transition to homogeneity will
depend mainly on the total surveyed area and the compactness of the surveyed
region. In particular, a Dark Energy Survey (DES)-like survey should be able to
easily discriminate certain fractal models with fractal dimensions as large as
D2 = 2.95. We believe that this method will have relevant applications for
upcoming large photometric redshift surveys, such as DES or the Large Synoptic
Survey Telescope (LSST).Comment: 14 pages, 14 figure
Deep into the Water Fountains: The case of IRAS 18043-2116
(Abridged) The formation of large-scale (hundreds to few thousands of AU)
bipolar structures in the circumstellar envelopes (CSEs) of post-Asymptotic
Giant Branch (post-AGB) stars is poorly understood. The shape of these
structures, traced by emission from fast molecular outflows, suggests that the
dynamics at the innermost regions of these CSEs does not depend only on the
energy of the radiation field of the central star. Deep into the Water
Fountains is an observational project based on the results of programs carried
out with three telescope facilities: The Karl G. Jansky Very Large Array
(JVLA), The Australia Telescope Compact Array (ATCA), and the Very Large
Telescope (SINFONI-VLT). Here we report the results of the observations towards
the WF nebula IRAS 180432116: Detection of radio continuum emission in the
frequency range 1.5GHz - 8.0GHz; HO maser spectral features and radio
continuum emission detected at 22GHz, and H ro-vibrational emission lines
detected at the near infrared. The high-velocity HO maser spectral
features, and the shock-excited H emission detected could be produced in
molecular layers which are swept up as a consequence of the propagation of a
jet-driven wind. Using the derived H column density, we estimated a
molecular mass-loss rate of the order of Myr. On the
other hand, if the radio continuum flux detected is generated as a consequence
of the propagation of a thermal radio jet, the mass-loss rate associated to the
outflowing ionized material is of the order of 10Myr.
The presence of a rotating disk could be a plausible explanation for the
mass-loss rates estimated.Comment: 10 pages, 5 figures. Accepted for publication in A&
On the molecules of numerical semigroups, Puiseux monoids, and Puiseux algebras
A molecule is a nonzero non-unit element of an integral domain (resp.,
commutative cancellative monoid) having a unique factorization into
irreducibles (resp., atoms). Here we study the molecules of Puiseux monoids as
well as the molecules of their corresponding semigroup algebras, which we call
Puiseux algebras. We begin by presenting, in the context of numerical
semigroups, some results on the possible cardinalities of the sets of molecules
and the sets of reducible molecules (i.e., molecules that are not
irreducibles/atoms). Then we study the molecules in the more general context of
Puiseux monoids. We construct infinitely many non-isomorphic atomic Puiseux
monoids all whose molecules are atoms. In addition, we characterize the
molecules of Puiseux monoids generated by rationals with prime denominators.
Finally, we turn to investigate the molecules of Puiseux algebras. We provide a
characterization of the molecules of the Puiseux algebras corresponding to
root-closed Puiseux monoids. Then we use such a characterization to find an
infinite class of Puiseux algebras with infinitely many non-associated
reducible molecules.Comment: 21 pages, 2 figure
The complex structure of HH 110 as revealed from Integral Field Spectroscopy
HH 110 is a rather peculiar Herbig-Haro object in Orion that originates due
to the deflection of another jet (HH 270) by a dense molecular clump, instead
of being directly ejected from a young stellar object. Here we present new
results on the kinematics and physical conditions of HH 110 based on Integral
Field Spectroscopy. The 3D spectral data cover the whole outflow extent (~4.5
arcmin, ~0.6 pc at a distance of 460 pc) in the spectral range 6500-7000 \AA.
We built emission-line intensity maps of H, [NII] and [SII] and of
their radial velocity channels. Furthermore, we analysed the spatial
distribution of the excitation and electron density from [NII]/H,
[SII]/H, and [SII] 6716/6731 integrated line-ratio maps, as well as
their behaviour as a function of velocity, from line-ratio channel maps. Our
results fully reproduce the morphology and kinematics obtained from previous
imaging and long-slit data. In addition, the IFS data revealed, for the first
time, the complex spatial distribution of the physical conditions (excitation
and density) in the whole jet, and their behaviour as a function of the
kinematics. The results here derived give further support to the more recent
model simulations that involve deflection of a pulsed jet propagating in an
inhomogeneous ambient medium. The IFS data give richer information than that
provided by current model simulations or laboratory jet experiments. Hence,
they could provide valuable clues to constrain the space parameters in future
theoretical works.Comment: 12 pages, 15 figures Accepted in MNRA
Estudio preliminar sobre algunas rocas volcánicas y volcano-sedimentarias de la provincia de Huelva
Se ha realizado una primera clasificación de algunas rocas volcánicas del Norte de la provincia de Huelva, con base geoquímica. De acuerdo con ésta, se apuntan algunas posibilidades genéticas
Estudio preliminar sobre algunas rocas volcánicas y volcano-sedimentarias de la provincia de Huelva
Se ha realizado una primera clasificación de algunas rocas volcánicas del Norte de la provincia de Huelva, con base geoquímica. De acuerdo con ésta, se apuntan algunas posibilidades genéticas
Inclusiones fluidas en el yacimiento aurífero de "El Cabaco" provincia de Salamanca
[Resumen] En este estudio se caracterizan las inclusiones fluidas en filones de cuarzo del área mineralizada de El Cabaco, asociados al granito hercínico de La Alberca-Sequeros en su borde noroccidental (Sur de la provincia de Salamanca). En los filones mineralizados, a lo largo de los planos de crecimiento del cuarzo, se han observado dos tipos principales de inclusiones fluidas desde un punto de vista composiciona1. Uno de ellos (tipo A) es rico en CH4, con cantidades menores de C02, y el otro (tipo B) es rico en H20 con C02 (± CH4). Estos datos se interpretan como el resultado de un fenómeno de inmiscibilidad de un fluido inicial rico en H20-CH4 y con algo de C02. También se han observado otras inclusiones (tipo C), grandes y abundantes (claramente secundarias) principalmente de dos fases, ricas en H20 y a veces con inclusiones minerales. En las zonas silicificadas o de greisen en torno a los filones, así como en un dique granítico, las inclusiones fluidas tienen una composición similar a la de los cuarzos filonianos. Sin embargo se han deducido temperaturas en formación de 485 ± 15°C para el dique granítico y el greisen y presiones algo menores a 1 Kb; los filones de cuarzo se formaron a temperaturas que no exceden 386°C y presiones menores de < 300 bares.[Abstract] This study characterizes fluid inclusions in veins associated with the emplacement of granite-hosted gold mineralization in the southern pan of the Province
of Salamanca Spain. Within the mineralized veins, along planes of quanz growth, two main different compositional types of fluid inclusions were observed. One type (A) is rich in CH4, with minar C02, and the type (B) is rich in H20 with C02 (± CH4). These
are interpreted as reflecting the inmiscibility of an initial fluid rich in H20CH4 and sorne C02. Large and abundant (cleary secondary) mainly two phase H20 rich inclusions (Type C) have seen observed also. Similar composition inclusion are seen in the granite cross-cutting vein mineralization and in the silification with mineralization of the greisen formed in a gra nitie dike. However, differenees regardin P-T conditions of formation have been dedueed from the interseetion of the isoehores obtained in the mierothermometrie study of the inclusions. These are eonsistent with the temperatures ealculated from the arsenopyrite-pyrite geothemometer (after mieroprobe measurement). Formation temperatures of 485 ± 15°C were dedueed for the mineralization in the greisen of the granitie dike and pressures under 1 x 108 Pa. The veins were formed at temperatures not exeeeding 386°C and < 300 x 105 Pa pressureFluid inclusions in the auriferous «El Cabaco» zone, Salamanca province, Spai
Advances in Classical Hodgkin Lymphoma Biology: New Prognostic Factors and Outcome Prediction Using Gene Expression Signatures
Resistance to eyespot (Pseudocercosporella herpotricoides) and distribution of biochemical markers in hexaploid lines derived from double cross (Triticum turgidum x Aegilops ventricosa) x T. aestivum
There are not good intraspecific sources of resistance to the eyespot disea se of wheat, aaused by Cercosporella herpotrichoides Fvon . The -ínterspecifia transfer of genes for resistanoe from Aegitops ventricosa into hexaploid wheat has been only partially achieved, because the degree of resistanoe attained is not as high as that of the donor. We report here on the transfer of resistanoe in a double oross (Triticum turgidum var. rubroatrwv H-1-1 x Ae.ventricosa AP-D x T.aestivum cv. Almatense H-10-15. The high level of resistanoe in a high proportion of the lines strongly suggests a simple genetic control for this oharacter (possibly by one major gene). The gene(s) responsible for resistanoe in the selected lines must be associa ted with the D genome of Aegilops ventricosa on the basis of a detailed study of the distribution of biochemioal markers in the H-93 lines. These results do not exelude that genes with similar effeets might be looated in the M° genome
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