325 research outputs found

    First record of the starfish Luidia atlantidea in the Canary Islands

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    We document the first observations of Luidia atlantidea Madsen, 1950 (Luidiidae; Paxillosida, Asteroidea) along the coasts of the Canary Islands, which represents a new westward occurrence of its known range. Individuals were observed during a visual scuba diving census in the islands of Gran Canaria (northwestern and eastern coasts) and Tenerife (eastern coast). These occurrences highlight the importance of the systematic biodiversity monitoring and surveillance of the dynamic changes in the environment, whereas future research is required to reveal the underpinnings for its presence.info:eu-repo/semantics/publishedVersio

    Morphological and functional abnormality in the spiny butterfly ray <i>Gymnura altavela</i>

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    Background: A variety of abnormalities have been described for sharks, rays and skates across different ecoregions. Morphological and functional anomalies in these species, however, were not yet documented in distributions from the Canary Islands, the spiny butterfly ray Gymnura altavela (Linnaeus, 1758) and from in situ observations. The aim of the present study is to fill these knowledge gaps.Results: A female spiny butterfly ray G. altavela with an unfused anterior part of the right pectoral fin to the neurocranium was observed in the port of Sardina del Norte (Gran Canaria Island) during a visual scuba diving census.Conclusion: The size and the observation of the activities swimming, burying and preying confirmed the adaption of the specimen for the anomaly and underdeveloped electrosensory system in its survival. The limited knowledge of teratogens and their triggering factors, and the striking similarity with an anomaly reported for G. poecilura (Shaw, 1804) from South India, suggest genetic expression aberrations or mechanical obstructions during gestation as origin for the disorder

    The complete mitochondrial genome of the critically endangered Angelshark, <i>Squatina squatina</i>

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    Here, we describe the first mitochondrial genome of the angelshark, Squatina squatina. The genome is 16,689 bp in length with 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a non-coding control region. Base composition of the mitogenome has an A + T bias (62.9%), seen commonly in other elasmobranchs. This genome provides a key resource for future investigations of the population genetic dynamics and evolution of this Critically Endangered shark

    Quantitative analysis of numerical estimates for the permeability of porous media from lattice-Boltzmann simulations

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    During the last decade, lattice-Boltzmann (LB) simulations have been improved to become an efficient tool for determining the permeability of porous media samples. However, well known improvements of the original algorithm are often not implemented. These include for example multirelaxation time schemes or improved boundary conditions, as well as different possibilities to impose a pressure gradient. This paper shows that a significant difference of the calculated permeabilities can be found unless one uses a carefully selected setup. We present a detailed discussion of possible simulation setups and quantitative studies of the influence of simulation parameters. We illustrate our results by applying the algorithm to a Fontainebleau sandstone and by comparing our benchmark studies to other numerical permeability measurements in the literature.Comment: 14 pages, 11 figure

    Algebraic computation of some intersection D-modules

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    Let XX be a complex analytic manifold, DXD\subset X a locally quasi-homogeneous free divisor, EE an integrable logarithmic connection with respect to DD and LL the local system of the horizontal sections of EE on XDX-D. In this paper we give an algebraic description in terms of EE of the regular holonomic D-module whose de Rham complex is the intersection complex associated with LL. As an application, we perform some effective computations in the case of quasi-homogeneous plane curves.Comment: 18 page

    Galaxy properties from J-PAS narrow-band photometry

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    We study the consistency of the physical properties of galaxies retrieved from SED-fitting as a function of spectral resolution and signal-to-noise ratio (SNR). Using a selection of physically motivated star formation histories, we set up a control sample of mock galaxy spectra representing observations of the local universe in high-resolution spectroscopy, and in 56 narrow-band and 5 broad-band photometry. We fit the SEDs at these spectral resolutions and compute their corresponding the stellar mass, the mass- and luminosity-weighted age and metallicity, and the dust extinction. We study the biases, correlations, and degeneracies affecting the retrieved parameters and explore the r\^ole of the spectral resolution and the SNR in regulating these degeneracies. We find that narrow-band photometry and spectroscopy yield similar trends in the physical properties derived, the former being considerably more precise. Using a galaxy sample from the SDSS, we compare more realistically the results obtained from high-resolution and narrow-band SEDs (synthesized from the same SDSS spectra) following the same spectral fitting procedures. We use results from the literature as a benchmark to our spectroscopic estimates and show that the prior PDFs, commonly adopted in parametric methods, may introduce biases not accounted for in a Bayesian framework. We conclude that narrow-band photometry yields the same trend in the age-metallicity relation in the literature, provided it is affected by the same biases as spectroscopy; albeit the precision achieved with the latter is generally twice as large as with the narrow-band, at SNR values typical of the different kinds of data.Comment: 26 pages, 15 figures. Accepted for publication in MNRA

    pyFIT3D and pyPipe3D -- The new version of the Integral Field Spectroscopy data analysis pipeline

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    We present a new version of the FIT3D and Pipe3D codes, two packages to derive properties of the stellar populations and the ionized emission lines from optical spectroscopy and integral field spectroscopy data respectively. The new codes have been fully transcribed to Python from the original Perl and C versions, modifying the algorithms when needed to make use of the unique capabilities of this language with the main goals of (1) respecting as much as possible the original philosophy of the algorithms, (2) maintaining a full compatibility with the original version in terms of the format of the required input and produced output files, and (3) improving the efficiency and accuracy of the algorithms, and solving known (and newly discovered) bugs. The complete package is freely distributed, with an available repository online. pyFIT3D and pyPipe3D are fully tested with data of the most recent IFS data surveys and compilations (e.g. CALIFA, MaNGA, SAMI and AMUSING++), and confronted with simulations. We describe here the code, its new implementation, its accuracy in recovering the parameters based on simulations, and a showcase of its implementation on a particular dataset.Comment: New Astronomy - 29 pages, 19 figures - Received on 7 Dec 2021 - Accepted for publication on 8 Jul 202

    Oral Health Status in Adult Population in Chile (Decayed, Missing, Filled and Permanent Tooth): Clinical Observation at National Level

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    Abstract Objectives: The aim of this study was to establish the differences in the oral health status of adult population between women and men by the clinical status of the permanent first molar. Methods: The data were obtained in a non-random sample of 132,174 patients from a large cohort who were under dental treatment nationwide in Chile during 2011. Results: The results show a greater frequency of &quot;filled and not decayed&quot; (45.6%), &quot;decayed&quot; (18.8%) and followed by &quot;missing by decay&quot; (15.4%). Moreover, an association is established between the &quot;filled and decayed&quot; condition to the female gender and the condition &quot;decayed&quot; and &quot;missing by decay&quot; to the male gender (Significance level α ≤ 0.05). Conclusions: This study concluded that there was a dependent association between gender and the oral health status of permanent first molars in adult patients. Keywords Chile * Corresponding author. V. Vargas-Sanhueza et al
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