2,452 research outputs found

    Variation in the Extraction Efficiency of Estradiol and Progesterone in Moist and Lyophilized Feces of the Black Howler Monkey (Alouatta pigra): Alternative Methods

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    Several fecal steroid extraction techniques have been developed to measure the ovary function in different species of mammals. However, regardless of the method of extraction and the sample type chosen, it has been observed that they can yield results with different percentages of recuperation. The objective of this study was to determine whether the type of substratum, solvent and extraction method used have any influence on the extraction efficiency in the feces of Alouatta pigra (black howler monkey). For this purpose we used two methods: agitation and ebullition. With each method, we utilized moist and lyophilized feces. The validation of radioimmunoassay method was accurate and precise for quantify estradiol and progesterone in lyophilized feces of A. pigra. To both of which ethanol and methanol, absolute and at 80%, were added, besides the hormones 125I-Estradiol and 125I-Progesterone. The extraction efficiency for 125I-Estradiol was from 87.72 ± 3.97 to 41.24 ± 2.67%, and for 125I-Progesterone from 71.15 ± 4.24 to 42.30 ± 1.19% when we used the agitation method. Whereas with the ebullition method, the extraction efficiency for 125I-Estradiol ranged from 86.89 ± 2.66 to 71.68 ± 3.02% and for 125I-Progesterone from 98.31 ± 1.26 to 85.40 ± 1.98%. Due to the differences found in these assays, which depend on the method used, the type of feces employed and the type of solvent added to them, we recommend the ebullition method and the lyophilized feces of A. pigra for extracting the hormones, since in moist feces there may exist variables which might interfere in the quantification of 125I-Estradiol and 125I-Progesterone

    Clues from Spitzer/IRS spectra on the Compton thickness and the existence of the dusty torus

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    [Context]: Most of the optically classified low-ionisation, narrow emission-line regions (LINERs) nuclei host an active galactic nucleus (AGN). However, how they fit into the unified model (UM) of AGN is still an open question. [Aims]: The aims of this work are to study at mid-infrared (mid-IR) (1) the Compton-thick nature of LINERs (i.e. hydrogen column densities of NH> 1.5 × 1024 cm-2) and (2) the disappearance of the dusty torus in LINERs predicted from theoretical arguments. [Methods]: We have compiled all the available low spectral-resolution, mid-IR spectra of LINERs from the InfraRed Spectrograph (IRS) onboard Spitzer. The sample contains 40 LINERs. We have complemented the LINER sample with Spitzer/IRS spectra of PGQSOs, Type-1 Seyferts (S1s), Type-2 Seyferts (S2s), and StarBurst (SB) nuclei. We studied the AGN compared to the starburst content in our sample using different indicators: the equivalent width of the polycyclic aromatic hydrocarbon at 6.2 μm, the strength of the silicate feature at 9.7 μm, and the steepness of the mid-IR spectra. We classified the spectra as SB-dominated and AGN-dominated, according to these diagnostics and compared the average mid-IR spectra of the various classes. Moreover, we studied the correlation between the 12 μm luminosity, νLν(12 μm), and the 2−10 keV energy band X-ray luminosity, LX(2−10 keV). [Results]: In 25 out of the 40 LINERs (i.e. 62.5%), the mid-IR spectra are not SB-dominated, similar to the comparison S2 sample (67.7%). The average spectra of both SB-dominated LINERs and S2s are very similar to the average spectrum of the SB class. The average spectrum of AGN-dominated LINERs is different from the average spectra of the other optical classes, showing a rather flat spectrum at 6-28 μm. We find that the average spectrum of AGN-dominated LINERs with X-ray luminosities LX(2−10 keV) > 1041 erg/s is similar to the average mid-IR spectrum of AGN-dominated S2s. However, faint LINERs (i.e. LX(2−10 keV) < 1041 erg/s) show flat spectra different from any of the other optical classes. The correlation between νLν(12 μm) and LX(2−10 keV) for AGN nicely extends towards low luminosities only if SB-dominated LINERs are excluded and if the 2−10 keV band X-ray luminosity is corrected in Compton-thick LINER candidates. [Conclusions]: We find that LINERs proposed as Compton-thick candidates at X-ray wavelengths may be confirmed according to the X-ray to mid-IR luminosity relation. We show evidence that the dusty-torus disappear when their bolometric luminosity is below Lbol ≃ 1042 erg/s. We suggest that the dominant emission at mid-IR of faint LINERs might be a combination of an elliptical galaxy host (characterised by the lack of gas), a starburst, a jet, and/or ADAF emission. Alternatively, the mid-IR emission of some of these faint LINERs could be a combination of elliptical galaxy plus carbon-rich planetary nebulae. To reconcile the Compton-thick nature of a large number of LINERs without dusty-torus signatures, we suggest that the material producing the Compton-thick X-ray obscuration is free of dust.This research has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under the grant (project refs. AYA2013-42227-P, AYA 2012-39168-C03-01, and AYA 2010-15169) and by La Junta de Andalucia (TIC 114). AAH acknowledges support from grant AYA2012-31447. D.D. acknowledges support from grant 107313 from PAPIIT, UNAM. C.R.A. is supported by a Marie Curie Intra European Fellowship within the 7th European Community Framework Programme (PIEF-GA-2012-327934).Peer Reviewe

    Applied interpolation methodology with GIS used for artisanal fishing zoning in Bahía Magdalena, Mexico

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    Objective: To limit the artisanal fishing zones in the water mirror of Magdalena Bay, by means of interpolation. Design/methodology/approach: Through surveys, social, economic and biological production data, wich are collected from a sample of 56 artisanal fishing cooperatives. The data is integrated into a relational database with geospatial reference and geostatistically processed with interpolation methods using a geographic information system. Results: Four zoning maps based on the interpolation of the variables target species, fishing effort, extraction volume and sale value. Limitations on study/implications: The remoteness and difficult access to the study area. Findings/conclusions: The methodology can be used at the national level and generate a limitation of the priority zones for artisanal fishing in Mexico, contributing to decision making and management plans that can consider the variables of the fishermen's social life

    Mucosa-associated lymphoid tissue lymphoma of the appendix stump: a case report

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    Primary lymphomas of the appendix occur in 0.015% of all gastrointestinal lymphomas. The most common manifestation is acute appendicitis secondary to luminal obstruction. The most common is immunophenotype B low-grade non-Hodgkin lymphoma. A 53-year-old male, with a previous three-week surgical history due to acute appendicitis, histopathological report of acute appendicitis and lymphoid hyperplasia. Later, he was admitted, with abdominal pain in the right iliac fossa, an abdominal ultrasound and simple abdominal tomography were performed, with suspicion of residual abscess. Surgical intervention is decided, observing paracecal tumor in the emergency site of the appendix, the tumor is removed. Pathological study that reports an appendicular base infiltrated by mucosa-associated lymphoma. The diagnosis of appendicular tumors is mostly, intraoperatively incidental. It is necessary to have the diagnostic possibility when performing an appendectomy, since it changes the prognosis and treatment of the patient

    Evolution of cosmic filaments in the MTNG simulation

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    We present a study of the evolution of cosmic filaments across redshift with emphasis on some important properties: filament lengths, growth rates, and radial profiles of galaxy densities. Following an observation-driven approach, we build cosmic filament catalogues at z=0,1,2,3 and 4 from the galaxy distributions of the large hydro-dynamical run of the MilleniumTNG project. We employ the extensively used DisPerSE cosmic web finder code, for which we provide a user-friendly guide, including the details of a physics-driven calibration procedure, with the hope of helping future users. We perform the first statistical measurements of the evolution of connectivity in a large-scale simulation, finding that the connectivity of cosmic nodes (defined as the number of filaments attached) globally decreases from early to late times. The study of cosmic filaments in proper coordinates reveals that filaments grow in length and radial extent, as expected from large-scale structures in an expanding Universe. But the most interesting results arise once the Hubble flow is factored out. We find remarkably stable comoving filament length functions and over-density profiles, showing only little evolution of the total population of filaments in the past ~12.25 Gyrs. However, by tracking the spatial evolution of individual structures, we demonstrate that filaments of different lengths actually follow different evolutionary paths. While short filaments preferentially contract, long filaments expand along their longitudinal direction with growth rates that are the highest in the early, matter dominated Universe. Filament diversity at fixed redshift is also shown by the different (~5σ5 \sigma) density values between the shortest and longest filaments. Our results hint that cosmic filaments can be used as additional probes for dark energy, but further theoretical work is still needed.Comment: 17 pages, submitted to Astronomy & Astrophysics, comments welcome

    Evolution of cosmic filaments in the MTNG simulation

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    We present a study of the evolution of cosmic filaments across redshift with an emphasis on some important properties: filament lengths, growth rates, and radial profiles of galaxy densities. Following an observation-driven approach, we built cosmic filament catalogues at z = 0, 1, 2, 3, and 4 from the galaxy distributions of the large hydro-dynamical run of the MilleniumTNG project. We employed the extensively used DisPerSE cosmic web finder code, for which we provide a user-friendly guide, including the details of a physics-driven calibration procedure, with the hope of helping future users. We performed the first statistical measurements of the evolution of connectivity in a large-scale simulation, finding that the connectivity of cosmic nodes (defined as the number of filaments attached) globally decreases from early to late times. The study of cosmic filaments in proper coordinates reveals that filaments grow in length and radial extent, as expected from large-scale structures in an expanding Universe. But the most interesting results arise once the Hubble flow is factored out. We find remarkably stable comoving filament length functions and over-density profiles, showing only little evolution of the total population of filaments in the past ∼12.25 Gyr. However, by tracking the spatial evolution of individual structures, we demonstrate that filaments of different lengths actually follow different evolutionary paths. While short filaments preferentially contract, long filaments expand along their longitudinal direction with growth rates that are the highest in the early, matter-dominated Universe. Filament diversity at a fixed redshift is also shown by the different (∼5σ) density values between the shortest and longest filaments. Our results hint that cosmic filaments can be used as additional probes for dark energy, but further theoretical work is still needed

    The Luminescent Properties and Atomic Structures of As-Grown and Annealed Nanostructured Silicon Rich Oxide Thin Films

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    Not long ago, we developed a theoretical model to describe a set of chemical reactions that can potentially occur during the process of obtaining Silicon Rich Oxide (SRO) films, an off stoichiometry material, notwithstanding the technique used to grow such films. In order to elucidate the physical chemistry properties of such material, we suggested the chemical reactions that occur during the process of growing of SRO films in particular for the case of the Low Pressure Chemical Vapor Deposition (LPCVD) technique in the aforementioned model. The present paper represents a step further with respect to the previous (published) work, since it is dedicated to the calculation by Density Functional Theory (DFT) of the optical and electronic properties of the as-grown and annealed SRO structures theoretically predicted on the basis of the previous work. In this work, we suggest and evaluate either some types of molecules or resulting nanostructures and we predict theoretically, by applying the DFT, the contribution that they may have to the phenomenon of luminescence (PL), which is experimentally measured in SRO films. We evaluated the optical and electronic properties of both the as-grown and the annealed structures
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