1,110 research outputs found

    A transiting super-Earth close to the inner edge of the habitable zone of an M0 dwarf star

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    We present a super-Earth orbiting close to the inner edge of the habitable zone of the cool dwarf star K2-286 (EPIC 249889081), detected with data from the K2 mission in its 15th15^{th} campaign. The planet has radius of 2.1±0.22.1\pm0.2 R_{\oplus}, near the 1.5 - 2.0 R_{\oplus} gap in the radii distribution. The equilibrium temperature is 34711+21347^{+21}_{-11} K, cooler than most of the small planets with well measured masses, and the orbital period is 27.359±0.00527.359\pm0.005 days. K2-286, located at a distance of 76.3±0.376.3\pm0.3 pc, is an M0V star with estimated effective temperature of 3926±1003926\pm100 K, less active than other M dwarf stars hosting exoplanets. The expected radial velocity semi-amplitude induced by the planet on the star is 1.91.2+1.31.9^{+1.3}_{-1.2} m\cdots1^{-1}, and the amplitude of signals in transit transmission spectroscopy is estimated at 5.0±3.05.0\pm3.0 ppm. Follow-up observations for mass measurements and transit spectroscopy should be desirable for this relatively bright target (mV=12.76,mKs=9.32m_V=12.76, m_{Ks}=9.32) hosting a transiting super-Earth within the inner edge of the habitable zone.Comment: Accepted for publication in MNRA

    Two planetary systems with transiting Earth-size and super-Earth planets orbiting late-type dwarf stars

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    We present two new planetary systems found around cool dwarf stars with data from the K2 mission. The first system was found in K2-239 (EPIC 248545986), char- acterized in this work as M3.0V and observed in the 14th campaign of K2. It consists of three Earth-size transiting planets with radii of 1.1, 1.0 and 1.1 R Earth, showing a compact configuration with orbital periods of 5.24, 7.78 and 10.1 days, close to 2:3:4 resonance. The second was found in K2-240 (EPIC 249801827), characterized in this work as M0.5V and observed in the 15th campaign. It consists of two transiting super-Earths with radii 2.0 and 1.8 R Earth and orbital periods of 6.03 and 20.5 days. The equilibrium temperatures of the atmospheres of these planets are estimated to be in the range of 380-600 K and the amplitudes of signals in transmission spectroscopy are estimated at ~10 ppm.Comment: Accepted for publication in MNRAS letter

    CARMENES input catalogue of M dwarfs IV. New rotation periods from photometric time series

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    Aims. The main goal of this work is to measure rotation periods of the M-type dwarf stars being observed by the CARMENES exoplanet survey to help distinguish radial-velocity signals produced by magnetic activity from those produced by exoplanets. Rotation periods are also fundamental for a detailed study of the relation between activity and rotation in late-type stars. Methods. We look for significant periodic signals in 622 photometric time series of 337 bright, nearby M dwarfs obtained by long-time baseline, automated surveys (MEarth, ASAS, SuperWASP, NSVS, Catalina, ASAS-SN, K2, and HATNet) and for 20 stars which we obtained with four 0.2-0.8 m telescopes at high geographical latitudes. Results. We present 142 rotation periods (73 new) from 0.12 d to 133 d and ten long-term activity cycles (six new) from 3.0 a to 11.5 a. We compare our determinations with those in the existing literature; we investigate the distribution of P rot in the CARMENES input catalogue,the amplitude of photometric variability, and their relation to vsin i and pEW(Halfa); and we identify three very active stars with new rotation periods between 0.34 d and 23.6 d.Comment: 34 pages, 43 figures, 2 appendix table

    Reflexiones sobre ‘Occupy. The spatial dynamics of discourse in global protest movements’ de Luisa Martin Rojo

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    La publicación del libro Occupy. The spatial dynamics of discourse in global protest movements, editado por Luisa Martin Rojo abre un nuevo campo para los estudios del discurso en el que se otorga centralidad al espacio en un sentido dinámico. Por este motivo, como parte del foro e-conversa (promovido por la Asociación Internacional de Estudios sobre Discurso y Sociedad EDiSo; http://www.edisoportal.org/) se planteó la lectura del capítulo introductorio (cuya traducción al español se encuentra en este número de Discurso y Sociedad) y debatir sobre algunas de las cuestiones que en él se plantean. El resultado está formado por varias contribuciones que, tomando como punto de partida el texto de Martín Rojo, reflexionan, entre otros temas, sobre las prácticas espaciales, el papel de los medios de comunicación y las redes sociales, el nuevo sujeto político emergente, las formaciones contrahegemónicas, el multilingüismo, prácticas prefigurativas, etc. De este modo, este texto dialógico es una invitación a seguir pensando el análisis del discurso desde una perspectiva novedosa ligada al espacio / The publication of the volumen Occupy. The spatial dynamics of discourse in global protest movements, edited by Luisa Martín Rojo, opens up a new field of discourse studies in which the focus lies on space, in a dynamic sense. For this reason, and as part of the forum e-conversa (hosted by the International Association of Discourse Studies and Society (EDiSo); http://www.edisoportal.org/Ediso), it was suggested to read the introduction (the Spanish translation of which is included in this issue of Discurso y Sociedad) and to debate over some of the topics presented in the book. The result consists of several contributions which, by taking Martin Rojo’s text as the starting point, reflect on spatial practices, the role of mass media and social networks, the new emerging political subject, counter-hegemonic formations, multilingualism, and prefigurative practices, among other issues. Thus, this dialogic text is an invitation to continue thinking about discourse analysis from a new perspective linked to space

    Local immune regulation of mucosal inflammation by tacrolimus

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    Purpose: Tacrolimus is a potent immunomodulator that is effective in the treatment of inflammatory bowel disease (IBD). However, potential toxicity and systemic effects with oral intake limit its use. Local tacrolimus treatment is effective in a subgrou

    A portal of educational resources: providing evidence for matching pedagogy with technology

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    The TPACK (Technology, Pedagogy and Content Knowledge) model presents the three types of knowledge that are necessary to implement a successful technology-based educational activity. It highlights how the intersections between TPK (Technological Pedagogical Knowledge), PCK (Pedagogical Content Knowledge) and TCK (Technological Content Knowledge) are not a sheer sum up of their components but new types of knowledge. This paper focuses on TPK, the intersection between technology knowledge and pedagogy knowledge – a crucial field of investigation. Actually, technology in education is not just an add-on but is literally reshaping teaching/learning paradigms. Technology modifies pedagogy and pedagogy dictates requirements to technology. In order to pursue this research, an empirical approach was taken, building a repository (back-end) and a portal (front-end) of about 300 real-life educational experiences run at school. Educational portals are not new, but they generally emphasise content. Instead, in our portal, technology and pedagogy take centre stage. Experiences are classified according to more than 30 categories (‘facets’) and more than 200 facet values, all revolving around the pedagogical implementation and the technology used. The portal (an innovative piece of technology) supports sophisticated ‘exploratory’ sessions of use, targeted at researchers (investigating the TPK intersection), teachers (looking for inspiration in their daily jobs) and decision makers (making decisions about the introduction of technology into schools)

    A systematic approach to the interrogation and sharing of standardised biofilm signatures

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    Publicado em "6th International Conference on Practical Applications of Computational Biology & Bioinformatics", ISBN 978-3-642-28838-8The study of microorganism consortia, also known as biofilms, is associated to a number of applications in biotechnology, ecotechnology and clinical domains. A public repository on existing biofilm studies would aid in the design of new studies as well as promote collaborative and incremental work. However, bioinformatics approaches are hampered by the limited access to existing data. Scientific publications summarise the studies whilst results are kept in researchers’ private ad hoc files. Since the collection and ability to compare existing data is imperative to move forward in biofilm analysis, the present work has addressed the development of a systematic computer-amenable approach to biofilm data organisation and standardisation. A set of in-house studies involving pathogens and employing different state-of-the-art devices and methods of analysis was used to validate the approach. The approach is now supporting the activities of BiofOmics, a public repository on biofilm signatures (http://biofomics.org).The authors thank, among others, Rosario Oliveira, Maria Joao Vieira, Idalina Machado, Nuno Cerca, Mariana Henriques, Pilar Teixeira, Douglas Monteiro, Melissa Negri, Susana Lopes, Carina Almeida and Helder Lopes, for submitting their data. The financial support from IBB-CEB, Fundacao para a Ciencia e Tecnologia (FCT) and European Community fund FEDER (Program COMPETE), project PTDC/SAU-ESA/646091/2006/FCOMP-01-0124-FEDER-007480, are also gratefully acknowledged

    Inhibitory effects of pharmacological doses of melatonin on aromatase activity and expression in rat glioma cells

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    Melatonin exerts oncostatic effects on different kinds of neoplasias, especially on oestrogen-dependent tumours. Recently, it has been described that melatonin, on the basis of its antioxidant properties, inhibits the growth of glioma cells. Glioma cells express oestrogen receptors and have the ability to synthesise oestrogens from androgens. In the present study, we demonstrate that pharmacological concentrations of melatonin decreases the growth of C6 glioma cells and reduces the local biosynthesis of oestrogens, through the inhibition of aromatase, the enzyme that catalyses the conversion of androgens into oestrogens. These results are supported by three types of evidence. Firstly, melatonin counteracts the growth stimulatory effects of testosterone on glioma cells, which is dependent on the local synthesis of oestrogens from testosterone. Secondly, we found that melatonin reduces the aromatase activity of C6 cells, measured by the tritiated water release assay. Finally, by (RT)–PCR, we found that melatonin downregulates aromatase mRNA steady-state levels in these glioma cells. We conclude that melatonin inhibits the local production of oestrogens decreasing aromatase activity and expression. By analogy to the implications of aromatase in other forms of oestrogen-sensitive tumours, it is conceivable that the modulation of the aromatase by pharmacological melatonin may play a role in the growth of glioblastomas

    Broadband 3-D shared aperture high isolation nine-element antenna array for on-demand millimeter-wave 5G applications

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    Universidad Carlos III de Madrid, European Union-Horizon 2020 [801538]; Ministerio de Ciencia, innovación y Universidades, Gobierno de España (MCIU/AEI/FEDER, UE) [RTI2018-095499-B-C31]Alibakhshikenari, M., Virdee, B.S., Vadalà, V., Dalarsson, M., de Cos Gómez, M.E., Alharbi, A.G., Burokur, S.N., Aïssa, S., Dayoub, I., Falcone, F., Limiti, E
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