2,767 research outputs found

    The kinematics of the quadrupolar nebula M1-75 and the identification of its central star

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    The link between the shaping of bipolar planetary nebulae and their central stars is still poorly understood. The kinematics and shaping of the multipolar nebula M 1-75 are hereby investigated, and the location and nature of its central star are briefly discussed. Fabry-Perot data from GHaFAS on the WHT sampling the Doppler shift of the [N II] 658.3 nm line are used to study the dynamics of the nebula, by means of a detailed 3-D spatio-kinematical model. Multi-wavelength images and spectra from the WFC and IDS on the INT, and from ACAM on the WHT, allowed us to constrain the parameters of the central star. The two pairs of lobes, angularly separated by ~22 degrees, were ejected simultaneously approx. ~3500-5000 years ago, at the adopted distance range from 3.5 to 5.0 kpc. The larger lobes show evidence of a slight degree of point symmetry. The shaping of the nebula could be explained by wind interaction in a system consisting of a post-AGB star surrounded by a disc warped by radiative instabilities. This requires the system to be a close binary or a single star which engulfed a planet as it died. On the other hand, we present broad- and narrow-band images and a low S/N optical spectrum of the highly-reddened, previously unnoticed star which is likely the nebular progenitor. Its estimated V-I colour allows us to derive a rough estimate of the parameters and nature of the central star.Comment: 8 pages, 6 figures, accepted for publication in Astronomy & Astrophysic

    Potential of the active heat pulse method with fiber optic temperature sensing for estimation of water content and infiltration in agricultural soils

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    The principle of temperature measurement along a fiber optic cable is based on the thermal sensitivity of the relative intensities of backscattered Raman Stokes and anti Stokes photons that arise from collisions with electrons in the core of the glass fiber. A laser pulse, generated by the Distributed Temperature Sensing unit DTS, traversing a fiber optic cable will result in Raman backscatter at two frequencies, referred to as Stokes and anti-Stokes

    Discovery of Halpha satellite emission in a low state of the SW Sextantis star BB Doradus

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    BB Dor was observed during its low state state in 2009. Signatures of both binary components are revealed in the average optical spectrum; no signature of accretion is observed. Narrow emission lines of Halpha, HeI and Na-D, as well as TiO absorption troughs trace the motion of the irradiated secondary star. We detect two additional components in the Halpha emission line that share many characteristics of similar "satellite" lines observed in the low state of magnetic cataclysmic variables of AM Her type. It is the first time such emission components are detected for an SW Sex star.Comment: 7 pages, 8 figures, accepted by MNRA

    Algal diversity associated with Patella candei candei D’Orbigny, 1840 (a limpet on the verge of extinction) on the island of Fuerteventura

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    Environmental degradation and over-fishing have taken the limpet Patella candei candei D´Orbigny, 1840 to the brink of extinction in the Canaries archipelago, where only a few populations persist on the island of Fuerteventura. Efforts to conserve this endemic Macaronesic species are centred on characterising the habitats of these different populations. Seaweed is an important resource in the feeding of this species, and therefore the study of marine flora and vegetation is necessary. In the present paper, 10 taxa are recorded for the first time on Fuerteventura; indeed, our citation of Nodularia harveyana Thuret ex Bornet et Flahault is the first for the entire Canary Islands.Los problemas ocasionados por la degradación medioambiental y la práctica de un marisqueo excesivo han llevado al gasterópodo Patella candei candei D'Orbigny, 1840 al borde de la extinción en el litoral canario, donde únicamente se mantienen algunas poblaciones en la isla de Fuerteventura. La conservación de este molusco endémico macaronésico se centra en la caracterización del hábitat de las diferentes poblaciones. Las algas son un recurso importante en la alimentación de esta especie, por ello es fundamental el estudio de la flora y la vegetación marinas de su entorno. En este trabajo se citan por primera vez diez especies de algas para la isla de Fuerteventura, y en él, la presencia de Nodularia harveyana Thuret ex Bornet et Flahault constituye la primera cita para el archipiélago canario.Instituto Español de Oceanografí

    Researchers' Seedbeds for the Development of Research Skills in Universities

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    The objective of this study is to demonstrate the effects of the application of the pedagogical strategy "researcher's seedbed" in the development of research skills in universities. This research is of quasi-experimental, longitudinal and prospective design, where 2 groups were formed: control and experimental, of 18 students each. A validated instrument was used to measure the research competences, as well as a rubric for the evaluation of the research projects. It began with a pre-test, and after 14 weeks of the development of the strategy, through different educational sessions, the post-test was administered. Likewise, the research projects carried out were evaluated. The results obtained showed that the pedagogical strategy had a positive effect on the development of research skills, with the highest evaluation being found in 40% of the students, with statistically significant differences between the control and experimental groups (Mann Whitney U, p=0.007), and between the pre-test and post-test (Wilcoxon, p=0.00). In the development of cognitive and procedural competence, an effect was also found in the strategy, but not in the attitudinal competence (Mann Whitney U, p=0.496). The application of this study is based on the fact that the formation of research groups in universities strengthens formative research in higher level students. This study shows the benefits of the implementation of strategies for the development of research competencies, since the product will be to train professionals with a scientific culture in favor of society

    Influencia de la fertilización inorgánica sobre la actividad microbiana del suelo

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    Las mediciones se llevaron a cabo en la campaña 2010/11 en un ensayo en el establecimiento Balducchi, ubicado en la localidad de Teodelina (Santa Fe), que forma parte de la Red de Nutrición CREA Sur de Santa Fe (CREA-IPNI-ASP). En ese ensayo, bajo rotación maíz-trigo/soja, se evalúan, anualmente desde la campaña 2000/01, fertilizaciones con N, P, S y micronutrientes en las siguientes combinaciones: PS, NS, NP, NPS, NPS+Micronutrientes, y Testigo (sin adición de fertilizante) en 3 repeticiones siguiendo un diseño en bloques completos al azar.Según la información obtenida, la actividad microbiana del suelo, medida por la cuantificación del consumo de diversas fuentes de C, fue influenciada por la fertilización inorgánica. De acuerdo al ACP, el tratamiento con nutrición más balanceada (NPS+Micros) registró mayor consumo de sustratos carbonados, que los restantes tratamientos. Según algunos autores, los fertilizantes inorgánicos afectan los parámetros biológicos debido al incremento del contenido de C orgánico del suelo, que determina el crecimiento de los microorganismos, siendo el P un factor clave en el aumento de la diversidad microbiana y fertilidad del suelo. Finalmente, el rendimiento del cultivo también se incrementó en respuesta a la fertilización, en comparación con el Testigo. Existe una compleja interacción entre el nivel óptimo de fertilización, la disponibilidad de nutrientes para el crecimiento de los microorganismos y el buen desarrollo de las plantas. Esto demuestra que son necesarios más estudios para profundizar el conocimiento acerca del efecto de la fertilización inorgánica sobre las funciones metabólicas de la microbiota del suelo.Fil: Conforto, C.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; ArgentinaFil: Correa, Olga Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; ArgentinaFil: Rovea, A.. Grupo Crea Santa Fe; ArgentinaFil: Boxler, M.. Grupo Crea Santa Fe; ArgentinaFil: Rodríguez Grastorf, S.. Grupo Crea Santa Fe; ArgentinaFil: Minteguiaga, J.. Grupo Crea Santa Fe; ArgentinaFil: Meriles, Jose Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Vargas Gil, Silvina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Genome-Wide Association Analysis for Stem Cross Section Properties, Height and Heading Date in a Collection of Spanish Durum Wheat Landraces

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    Durum wheat landraces have a high potential for breeding but they remain underexploited due to several factors, including the insufficient evaluation of these plant materials and the lack of efficient selection tools for transferring target traits into elite backgrounds. In this work, we characterized 150 accessions of the Spanish durum wheat collection for stem cross section, height and heading date. Continuous variation and high heritabilities were recorded for the stem area, pith area, pith diameter, culm wall thickness, height and heading date. The accessions were genotyped with DArTSeq markers, which were aligned to the durum wheat ‘Svevo’ genome. The markers corresponding to genes, with a minor allele frequency above 5% and less than 10% of missing data, were used for genome-wide association scan analysis. Twenty-nine marker-trait associations (MTAs) were identified and compared with the positions of previously known QTLs. MTAs for height and heading date co-localized with the QTLs for these traits. In addition, all the MTAs for stem traits in chromosome 2B were located in the corresponding synteny regions of the markers associated with lodging in bread wheat. Finally, several MTAs for stem traits co-located with the QTL for wheat stem sawfly (WSS) resistance. The results presented herein reveal the same genomic regions in chromosome 2B are involved in the genetic control of stem traits and lodging tolerance in both durum and bread wheat. In addition, these results suggest the importance of stem traits for WSS resistance and the potential of these landraces as donors for lodging tolerance and WSS resistance enhancement. In this context, the MTAs for stem-related traits identified in this work can serve as a reference for further development of markers for the introgression of target traits into elite materialThis research was funded by the Instituto de Investigación y Formación Agraria y Pesquera (IFAPA), Junta de Andalucía, grant number AVA-AVA2019.020 cofounded at 80% by FEDER. C.M.A., J.S. and S.G.A. are members of the FiRCMe Network, funded by Ministerio de Economía, Industria y Competitividad (AGL2016-81855-REDT). M.D.R.-R. was the recipient of a fellowship from the Ministerio de Ciencia, Innovación y Universidades (PRE2018-084037)
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