2,067 research outputs found

    Respuesta hipofisaria y ovulatoria de conejas nulíparas alimentadas con dietas suplementadas con ácidos grasos poliinsaturados n-3.

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    Veinte conejas nulíparas se alimentaron ad libitum desde las 10 a las 16 semanas de edad con dos piensos isofibrosos, isoenergéticos e isoproteicos suplementados con dos fuentes de grasa diferentes: 0,75% de manteca para la dieta control (grupo C; n=10) ó 1,5% de un suplemento (Optomega-50; Optivite International Ltd., España) que contenía un 50% de extracto etérero y 38% de ácidos grasos poli-insaturados n-3 (AG n-3) para la dieta experimental (grupo P; n=10). A las 16 semanas de edad se determinó el consumo de pienso, así como la tasa de ovulación y las concentraciones plasmáticas de progesterona y LH a 0, 60 min, 5, 7 y 9 días post-inducción de ovulación con 20 μg de Gonadorelina (Inducel-GnRH, Lab. Ovejero). El consumo de pienso (150,5 g/d), el pico preovulatorio de LH (149,7±10,9 ng/ml), la tasa de ovulación (95%) y el número de cuerpos lúteos (9,8±0,7) fueron similares entre tratamientos. Las concentraciones plasmáticas de progesterona aumentaron a los 60 minutos (7,13±19 ng/ml) y 5 días (13,3±1,9 ng/ml) con respecto al día 0 (0,7±1,9 ng/ml; P<0.05), permaneciendo elevadas el día 9 en ambos grupos (19,4±1,9 ng/ml). Además, el día 5 y 7 post-inducción, las hembras alimentadas con la dieta P tendieron a tener niveles más elevados de progesterona en sangre que las alimentadas con la dieta C (16,6±1,9 vs.12,6±1,8 y 19,0±1,8 vs. 15,5±2,1 ng/ml, P=0,068 y P=0,082; respectivamente) que coinciden con el momento de la implantación embrionaria en esta especie. Por lo tanto, la suplementación con AG n-3 podría mejorar los niveles de progesterona en sangre y por lo tanto reducir la mortalidad embrionaria en este punto

    Fractal analysis applied to light curves of δ\delta Scuti stars

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    Fractal behaviour, i.e. scale invariance in spatio-temporal dynamics, have been found to describe and model many systems in nature, in particular fluid mechanics and geophysical related geometrical objects, like the convective boundary layer of cumulus cloud fields, topographic landscapes, solar granulation patterns, and observational astrophysical time series, like light curves of pulsating stars. The main interest in the study of fractal properties in such physical phenomena lies in the close relationships they have with chaotic and turbulent dynamic. In this work we introduce some statistical tools for fractal analysis of light curves: Rescaled Range Analysis (R/S), Multifractal Spectra Analysis, and Coarse Graining Spectral Analysis (CGSA), an FFT based algorithm, which can discriminate in a time series the stochastic fractal power spectra from the harmonic one. An interesting application of fractal analysis in asteroseismology concerns the joint use of all these tools in order to develop classification criteria and algorithms for {\delta}-Scuti pulsating stars. In fact from the fractal and multi-fractal fingerprints in background noise of light curves we could infer on different mechanism of stellar dynamic, among them rotation, modes excitation and magnetic activity.Comment: 13 pages, 10 figure

    Gender equality in STEM programs: a proposal to analyse the situation of a university about the gender gap

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    [EN]According to the Global Gender Gap Report 2020, most of the countries have achieved gender parity in educational attainment. Furthermore, Latin America and Europe have more women than men enrolled in tertiary education. The problem arises when those numbers are analysed by degree studies. There is a gender gap in science, technology, engineering and mathematics (STEM), with a low number of women enrolled in those programs and even lower numbers of graduates. The universities have a key role to steer new conceptions and understanding of the females in STEM . The higher education institutions have to define measures and policies to reduce the gender gap in the careers of the future. This work aims to provide a proposal to analyse the gender equality gap in STEM as a first step to define gender equality action plans focused on processes of attraction, access and retention and guidance in STEM programs. The proposal was applied in ten Latin American universities from Chile, Colombia, Costa Rica, Ecuador and Mexico, and five European universities from Finland, Ireland, Italy, Spain, United Kingdom

    Respuesta hipofisaria y ovulatoria de conejas nulíparas alimentadas con dietas suplementadas con ácidos grasos poliinsaturados n-3

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    Twenty rabbit does were fed ad libitum from 10 to 16 weeks of age two isofibrous, isoenergetic and isoproteic diets (n=10) supplemented with two different fat sources: 0.75% lard for diet C (control) or 1.5% of a supplement (Optomega-50; Optivite International Ltd., Spain) containing a 50% of EE and 38% of n-3 polyunsaturated fatty acids for diet P (PUFA n-3). Does feed intake, ovulation rate and plasma progesterone and LH concentrations at 0, 60 min, 5, 7 and 9 days post-induction of ovulation with 20 μg of Gonadorelina (Inducel-GnRH, Lab. Ovejero) at 16 weeks of age were assessed. Average daily intake (150.5 g/d), ovulation rate (95%), preovulatory peak of plasma LH (149.7±10.9 ng/ml ng/ml) and number of corpora lutea (9.8±0.7) were similar between dietary treatments. Plasma progesterone concentrations increased at 60 minutes (7.13±1.9 ng/ml) and 5 days (13.3±1.9 ng/ml) after induction with respect to day 0 (0.7±1.9 ng/ml; P&lt;0.05), remaining constant afterward in both groups (19.4±1.9 ng/ml). Moreover, plasma progesterone of does fed diet P tended to be higher than for diet C on day 5 and 7 post-induction (16.6±1.9 vs.12.6±1.8 and 19.0±1.8 vs. 15.5±2.1 ng/ml, P=0.068 and P=0.082; respectively). Therefore, PUFA n-3 supplementation in does rabbit diets might be related with high progesterone levels and reduced early embryo mortality.Veinte conejas nulíparas se alimentaron ad libitum desde las 10 a las 16 semanas de edad con dos piensos isofibrosos, isoenergéticos e isoproteicos suplementados con dos fuentes de grasa diferentes: 0,75% de manteca para la dieta control (grupo C; n=10) ó 1,5% de un suplemento (Optomega-50; Optivite International Ltd., España) que contenía un 50% de extracto etérero y 38% de ácidos grasos poli-insaturados n-3 (AG n-3) para la dieta experimental (grupo P; n=10). A las 16 semanas de edad se determinó el consumo de pienso, así como la tasa de ovulación y las concentraciones plasmáticas de progesterona y LH a 0, 60 min, 5, 7 y 9 días post-inducción de ovulación con 20 μg de Gonadorelina (Inducel-GnRH, Lab. Ovejero). El consumo de pienso (150,5 g/d), el pico preovulatorio de LH (149,7±10,9 ng/ml), la tasa de ovulación (95%) y el número de cuerpos lúteos (9,8±0,7) fueron similares entre tratamientos. Las concentraciones plasmáticas de progesterona aumentaron a los 60 minutos (7,13±19 ng/ml) y 5 días (13,3±1,9 ng/ml) con respecto al día 0 (0,7±1,9 ng/ml; P&lt;0.05), permaneciendo elevadas el día 9 en ambos grupos (19,4±1,9 ng/ml). Además, el día 5 y 7 post-inducción, las hembras alimentadas con la dieta P tendieron a tener niveles más elevados de progesterona en sangre que las alimentadas con la dieta C (16,6±1,9 vs.12,6±1,8 y 19,0±1,8 vs. 15,5±2,1 ng/ml, P=0,068 y P=0,082; respectivamente) que coinciden con el momento de la implantación embrionaria en esta especie. Por lo tanto, la suplementación con AG n-3 podría mejorar los niveles de progesterona en sangre y por lo tanto reducir la mortalidad embrionaria en este punto

    Rotation and pulsation in Ap stars: first light results from TESS sectors 1 and 2

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    We present the first results from the Transiting Exoplanet Survey Satellite (TESS) on the rotational and pulsational variability of magnetic chemically peculiar A-type stars. We analyse TESS 2-min cadence data from sectors 1 and 2 on a sample of 83 stars. Five new rapidly oscillating Ap (roAp) stars are announced. One of these pulsates with periods around 4.7 min, making it the shortest period roAp star known to date. Four out of the five new roAp stars are multiperiodic. Three of these, and the singly-periodic one show the presence of rotational mode splitting. Individual frequencies are provided in all cases. In addition, seven previously known roAp stars are analysed. Additional modes of oscillation are found in some stars, while in others we are able to distinguish the true pulsations from possible aliases present in the ground-based data. We find that the pulsation amplitude in the TESS filter is typically a factor 6 smaller than that in the B filter which is usually used for ground-based observations. For four roAp stars we set constraints on the inclination angle and magnetic obliquity, through the application of the oblique pulsator model. We also confirm the absence of roAp-type pulsations down to amplitude limits of 6 and 13 micromag, respectively, in two of the best characterised non-oscillating Ap (noAp) stars. We announce 27 new rotational variables along with their rotation periods, and provide different rotation periods for seven other stars. Finally, we discuss how these results challenge state-of-the-art pulsation models for roAp stars.We thank the referee for very detailed and useful comments to the original manuscript. This work was supported by FCT - Fundação para a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalização by these grants: UID/FIS/04434/2019, PTDC/FIS-AST/30389/2017 & POCI-01- 0145-FEDER-030389. MC is supported in the form of work contract funded by national funds through FCT. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (Grant agreement no.: DNRF106). DLH and DWK acknowledge financial support from the Science and Technology Facilities Council (STFC) via grant ST/M000877/1. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. LFM acknowledges support from the UNAM by the way of DGAPA project PAPIIT IN100918. The research leading to these results has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement N 670519: MAMSIE) and from the Fonds Wetenschappelijk Onderzoek - Vlaanderen (FWO) under the grant agreement G0H5416N (ERC Opvangproject). MS acknowledges the financial support of Postdoc@MUNI project CZ.02.2.69/0.0/0.0/16 027/0008360. EN acknowledges the Polish National Science Center grants no.2014/13/B/ST9/00902. JCS acknowledges funding support from Spanish public funds for research under projects ESP2017-87676-2-2 and ESP2015- 65712-C5-5-R, and from project RYC-2012-09913 under the ‘Ramón y Cajal’ program of the Spanish Ministry of Science and Education. AGH acknowledges funding support from Spanish public funds for research under projects ESP2017-87676-2-2 and ESP2015-65712-C5-5-R of the Spanish Ministry of Science and Education. A´ S, ZsB, and RSz acknowledge the financial support of the GINOP-2.3.2-15-2016- 00003, K-115709, K-113117, K-119517 and PD-123910 grants of the Hungarian National Research, Development and Innovation Office (NKFIH), and the Lendület Program of the Hungarian Academy of Sciences, project No. LP2018-7/2018. GH has been supported by the Polish NCN grant 2015/18/A/ST9/00578. MLM acknowledges funding support from Spanish public funds for research under project ESP2015- 65712-C5-3-R. JPG acknowledges funding support from Spanish public funds for research under project ESP2017-87676-C5-5-R. MLM and JPG also acknowledges funding support from the State Agency for Research of the Spanish MCIU through the ”Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709). IS acknowledges funding support of NSF under projects DN 08-1/2016 and DN 18/13-12.12.2017. P. Kołaczek-Szymański acknowledges support from the NCN grant no. 2016/21/B/ST9/01126. This paper includes data collected by the TESS mission. Funding for the TESS mission is provided by the NASA Explorer Program

    Optimization problems in electron microscopy of single particles

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s10479-006-0078-8Electron Microscopy is a valuable tool for the elucidation of the three-dimensional structure of macromolecular complexes. Knowledge about the macromolecular structure provides important information about its function and how it is carried out. This work addresses the issue of three-dimensional reconstruction of biological macromolecules from electron microscopy images. In particular, it focuses on a methodology known as “single-particles” and makes a thorough review of all those steps that can be expressed as an optimization problem. In spite of important advances in recent years, there are still unresolved challenges in the field that offer an excellent testbed for new and more powerful optimization techniques.We acknowledge partial support from the “Comunidad Autónoma de Madrid” through grants CAM-07B-0032-2002, GR/SAL/0653/2004 and GR/SAL/0342/2004, the “Comisión Interministerial de Ciencia yTecnologia” of Spain through grants BIO2001-1237, BIO2001-4253-E, BIO2001-4339-E, BIO2002- 10855-E, BFU2004-00217/BMC, the Spanish FIS grant (G03/185), the European Union through grants QLK2- 2000-00634, QLRI-2000-31237, QLRT-2000-0136, QLRI-2001-00015, FP6-502828 and the NIH through grant HL70472. Alberto Pascual and Roberto Marabini acknowledge support by the Spanish Ramon y Cajal Program

    Digestibilidad y respuesta ovárica de conejas reproductoras alimentadas con dietas suplementadas con ácidos grasos poliinsaturados n-3

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    Aumentar el número de gazapos destetados por coneja y parto es un objetivo importante para incrementar la rentabilidad del sector cunícola industrial con efectos directos. La mejora genética de la prolificidad en las líneas de madres ha demostrado ser una estrategia eficaz para alcanzar este objetivo; sin embargo otras vías, como la influencia de diferentes fuentes de grasa en las dietas de conejas reproductoras, han sido muy poco estudiadas. Los ácidos grasos (AG) n-3 interfieren en la fisiología reproductiva porque pueden modular las enzimas involucradas en el metabolismo de las prostaglandinas y del colesterol que es el precursor de los esteroides como la progesterona (revisado en Gulliver et al., 2012). El objetivo de este trabajo es estudiar si la suplementación con AG poliinsaturados (PUFA) n-3 de las dietas de conejas durante la recría puede afectar a la tasa de ovulación y a la síntesis esteroidogénica ovárica determinada mediante las concentraciones de progesterona plasmática

    Chemical recycling of plastics assisted by microwave multi-frequency heating

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    Handling plastic waste through recycling allows extending the life of polymeric materials, avoiding recurrence to incineration or landfilling. In contrast with traditional mechanical recycling technologies, chemical recycling enables the obtention of the virgin monomers by means of depolymerisation to create new polymers with the same mechanical and thermal properties as the originals. Research presented in this paper is part of the polynSPIRE project (Horizon 2020 European funding programme) and develops and scales-up a heated reactor to carry out the depolymerisation of polyamide-6 (PA6), polyamide-6, 6 (PA66) and polyurethane (PU) using microwave (MW) technology as the heating source. The purpose is to design and optimize a MW reactor using up to eight ports emitting electromagnetic waves. Finite element method (FEM) simulation and optimisation are used to design the reactor, considering as parameters the data obtained from experimental dielectric testing and lab-scale characterisation of the processes and materials studied. Two different COMSOL Multiphysics modules are involved in this work: Radio Frequency (RF) and Chemical Reaction Engineering (RE), to simulate the reactor cavity using two frequency levels (915 MHz and 2.45 GHz) with a power level of 46 kW, and the chemical depolymerisation process, respectively. A sensitivity study has been performed on key parameters such as the frequency, the number of ports, and position inside the reactor to consolidate the final design. It is expected that these results assist in the design and scale-up of microwave technology for the chemical recycling of plastics, and for the large-scale deployment of this sustainable recovery alternative. © 2021 The Author
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