2,183 research outputs found
Catálogo actualizado de los Geometridae (Lepidoptera: Geometroidea) de Chile. Parte I: Archiearinae, Geometrinae y Sterrhinae
The Geometridae are the second most diverse family of Lepidoptera. Seven subfamilies of geometrid moths have been recognized worldwide, and fi ve of those have been recorded in Chile. The highest species richness of Chilean Geometrids is concentrated in Ennominae and Larentiinae, subfamilies that will be treated in subsequent volumes of this catalog. The earlier catalogue of the Chilean geometrid moths was published by Angulo & Casanueva (1981), who listed species with no more records that type locality and some fl ight periods. Since then, much of the taxonomic knowledge has changed, resulting in new combinations and descriptions of numerous new species, as well as establishing new species records for Chile. For each species, we include BIN number (if available), synonymy, biological data, host, references, known geographical distribution, fl ight period and reference photographs of species. In order to obtain both old and new data, we used specimens from different national and international scientifi c collections. The result was a review of 13 geometrid moths, which represent the three less known subfamilies of this group in Chile: Archiearinae, Geometrinae and Sterrhinae.Los Geometridae son la segunda familia más diversa de Lepidoptera. Siete subfamilias de geométridos han sido reconocidas en todo el mundo, y cinco de ellas han sido registradas en Chile. La mayor riqueza de especies de geométridos chilenos se concentra en Ennominae y Larentiinae, subfamilias que se tratarán en volúmenes posteriores de este catálogo. El anterior catálogo de geométridos chilenos fue publicado por Angulo & Casanueva (1981), quienes enumeraron las especies con no más registros que la localidad tipo y algunos períodos de vuelo. Desde entonces, gran parte del conocimiento taxonómico ha cambiado, dando como resultado nuevas combinaciones y descripciones de numerosas especies nuevas, así como el establecimiento de nuevos registros de especies para Chile. Para cada especie, incluimos el número de BIN (si está disponible), la sinonimia, los datos biológicos, hospederos, referencias bibliográfi cas, distribución geográfi ca conocida, período de vuelo y fotografías de referencia de las especies. Con el fi n de obtener datos antiguos y nuevos, utilizamos muestras de diferentes colecciones científi cas nacionales e internacionales. El resultado fue una revisión de 13 geométridos, los que representan las tres subfamilias menos conocidas de este grupo en Chile: Archiearinae, Geometrinae y Sterrhinae
Close Binary Stars in Planetary Nebulae through Gaia EDR3
This article belongs to the Proceedings of The 4th XoveTIC Conference[Abstract] The aim of this work is to search for evidence of close binary stars associated with planetary nebulae (ionized stellar envelopes in expansion) by mining the astronomical archive of Gaia EDR3. For this task, using big data techniques, we selected a sample of central stars of planetary nebulae from almost 2000 million sources in an EDR3 database. Then, we analysed some of their parameters, which could provide clues about the presence of close binary systems, and we ran a statistical test to verify the results. Using this method, we concluded that red stars tend to show more affinity with close binarity than blue ones.Funding from Spanish Ministry project RTI2018-095076-B-C22, Xunta de Galicia ED431B 2021/36, and AYA-2017-88254-P is acknowledged by the authors. IGS acknowledges financial support from the Spanish National Programme for the Promotion of Talent and its Employability grant BES-2017-083126 cofunded by the European Social FundXunta de Galicia; ED431B 2021/3
The structural impact of DNA mismatches
© 2015 © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research. The structure and dynamics of all the transversion and transition mismatches in three different DNA environments have been characterized by molecular dynamics simulations and NMR spectroscopy. We found that the presence of mismatches produced significant local structural alterations, especially in the case of purine transversions. Mismatched pairs often show promiscuous hydrogen bonding patterns, which interchange among each other in the nanosecond time scale. This therefore defines flexible base pairs, where breathing is frequent, and where distortions in helical parameters are strong, resulting in significant alterations in groove dimension. Even if the DNA structure is plastic enough to absorb the structural impact of the mismatch, local structural changes can be propagated far from the mismatch site, following the expected through-backbone and a previously unknown through-space mechanism. The structural changes related to the presence of mismatches help to understand the different susceptibility of mismatches to the action of repairing proteins.Peer Reviewe
Maximum gravitational recoil
Recent calculations of gravitational radiation recoil generated during
black-hole binary mergers have reopened the possibility that a merged binary
can be ejected even from the nucleus of a massive host galaxy. Here we report
the first systematic study of gravitational recoil of equal-mass binaries with
equal, but anti-aligned, spins parallel to the orbital plane. Such an
orientation of the spins is expected to maximize the recoil. We find that
recoil velocity (which is perpendicular to the orbital plane) varies
sinusoidally with the angle that the initial spin directions make with the
initial linear momenta of each hole and scales up to a maximum of ~4000 km/s
for maximally-rotating holes. Our results show that the amplitude of the recoil
velocity can depend sensitively on spin orientations of the black holes prior
to merger.Comment: 4 pages, 4 figs, revtex
The complexity of a numerical semigroup
Let S and Delta be numerical semigroups. A numerical semigroup S is an I(Delta)-semigroup if S \ {0} is an ideal of Delta. We denote by J (Delta) = {S vertical bar S is an I(Delta)-semigroupg, and we say that Delta is an ideal extension of S if S is an element of J (Delta). In this work, we present an algorithm to build all the ideal extensions of a numerical semigroup. We recursively denote by J(0) (N) = N; J(1)(N) = J (N) and J(k+1) (N) = J (J(k) (N)) for all k is an element of N: The complexity of a numerical semigroup S is the minimum of the set {k is an element of N vertical bar S is an element of J(k) (N)}. In addition, we introduce an algorithm to compute all the numerical semigroups with fixed multiplicity and complexity.Junta de Andalucia
MTM2017-84890-
Solvent-controlled diastereoselectivity in tryptophan-catalyzed Mannich reactions
Solvent effects in the L-tryptophan-catalyzed Mannich reaction between hydroxyacetone and glyoxylate imines have been examined. The use of a DMSO/1-butanol (4:1 v/v) mixture as solvent at rt provided the expected Mannich adducts in good yields, high anti-diastereoselectivity (up to 10.3:1 anti/syn ratio) and excellent enantioselectivities (up to >99.9% ee for the anti isomer
Globular Clusters: DNA of Early-Type galaxies?
This paper explores if the mean properties of Early-Type Galaxies (ETG) can
be reconstructed from "genetic" information stored in their GCs (i.e., in their
chemical abundances, spatial distributions and ages). This approach implies
that the formation of each globular occurs in very massive stellar
environments, as suggested by some models that aim at explaining the presence
of multi-populations in these systems. The assumption that the relative number
of globular clusters to diffuse stellar mass depends exponentially on chemical
abundance, [Z/H], and the presence of two dominant GC sub-populations blue and
red, allows the mapping of low metallicity halos and of higher metallicity (and
more heterogeneous) bulges. In particular, the masses of the low-metallicity
halos seem to scale up with dark matter mass through a constant. We also find a
dependence of the globular cluster formation efficiency with the mean projected
stellar mass density of the galaxies within their effective radii. The analysis
is based on a selected sub-sample of galaxies observed within the ACS Virgo
Cluster Survey of the {\it Hubble Space Telescope}. These systems were grouped,
according to their absolute magnitudes, in order to define composite fiducial
galaxies and look for a quantitative connection with their (also composite)
globular clusters systems. The results strengthen the idea that globular
clusters are good quantitative tracers of both baryonic and dark matter in
ETGs.Comment: 20 pages, 28 figures and 5 table
Mining of the Milky Way Star Archive Gaia-DR2: Searching for Binary Stars in Planetary Nebulae
This article belongs to the Proceedings of 3rd XoveTIC Conference[Abstract]
The aim of this work is to search for binary stars associated to planetary nebulae (ionized stellar envelopes in expansion), by mining the astronomical archive of Gaia DR2, that is composed by around 1.7 billion stellar sources. For this task, we selected those objects with coincident astrometric parameters (parallaxes and proper motions) with the corresponding central star, among a sample of 211 planetary nebulae. By this method, we found eight binary systems, and we obtained their components positions, separations, temperatures and luminosities, as well as some of their masses and ages. In addition, we estimated the probability for each companion star of having been detected by chance and we analyzed how the number of false matches increase as the separation distance between both stars gets larger. All these procedures have been carried out making use of data mining techniques.Funding from Spanish Ministry projects ESP2016-80079-C2-2-R, RTI2018-095076-BC22, Xunta de
Galicia ED431B 2018/42, and AYA-2017-88254-P is acknowledged by the authors. M.M. thanks the Instituto de Astrofísica de Canarias for a visiting stay funded by the Severo Ochoa Excellence programme. IGS acknowledges financial support from the Spanish National Programme for the Promotion of Talent and its Employability grant BES-2017-083126 cofunded by the European Social FundXunta de Galicia; ED431B 2018/4
Gaia DR2 Distances to Planetary Nebulae
[Abstract] The aim of this work is to examine distances to planetary nebulae (PNe) together with other properties that were derived from them, using the astrometry of Gaia Data Release 2 (DR2). We were able to identify 1571 objects classified as PNe, for which we assumed distances calculated following a Bayesian statistical approach. From those objects, we selected a sample of PNe with good quality parallax measurements and distance derivations, which we called Golden Astrometry PNe sample (GAPN). In this paper we will review the physical properties of the stars and nebulae in this subsample of PNe.Xunta de Galicia; ED431B 2018/42Funding from Spanish Ministry projects ESP2016-80079-C2-2-R, RTI2018-095076-BC22, Xunta de Galicia ED431B 2018/42, and AYA-2017-88254-P is acknowledged by the authors. M.M. thanks the Instituto de Astrofísica de Canarias for a visiting stay funded by the Severo Ochoa Excellence programme. IGS acknowledges financial support from the Spanish National Programme for the Promotion of Talent and its Employability grant BES-2017-083126 cofunded by the European Social Fun
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