2,036 research outputs found

    Respuestas de alimentación de Scolytus scolytus a extractos del floema de ramillas de olmo

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    Feeding responses by Scolytus scolytus were tested using elm twig bark extracts in a laboratory bioassay. One to 4- years-old elm twigs or small branches were sampled in spring and their bark extracted separately with methanol and with a mixture of petroleum ether and diethyl ether (1:1) as solvents. Bark extracts were tested in a two choice feeding bioassay consisting of two polyurethane discs placed in a 10 cm diameter Petri dish. Extracts were applied onto the discs and the amount of disc eaten by ten freshly emerged S. scolytus adults was recorded after 24 hours. Ten U. minor, two U. laevis, six U. glabra, three Dutch hybrids (European x Asiatic) and one U. pumila trees were tested in several comparisons. Discs with extracts from both U. laevis trees were significantly less eaten than those from U. pumila or from U. minor trees in two choice tests. Similarly, extracts from all U. glabra trees received less feeding than those from U. minor. On the contrary, S. scolytus showed no difference in feeding between U. pumila and U. minor extracts, and similarly for Dutch hybrids in comparison with two U. minor clones. Again, beetles preferred to feed on Dutch hybrid extracts better than in those from U. laevis. Significant intraspecific differences in feeding were obtained in U. minor. One of the U. minor clones resulted less chosen when compared to other four trees. Extracts from a dying U. minor tree received more feeding than those from a healthy tree. Comparisons were also made between bark extracts from 2-to 4-year-old vs. current-year twigs within the same trees. In one of the four U. minor tested, a significant preference for the older twig extracts was recorded.Se estudió la respuesta de alimentación de S. scolytus a extractos del floema de ramillas de olmo en bioensayos de laboratorio. Se muestrearon en primavera ramillas de olmo de uno a cuatro años de edad y su floema fue extraído independientemente con metanol o con una mezcla de eter de petróleo y eter dietílico (1:1). Los extractos del floema se evaluaron en un bioensayo de doble elección consistente en dos discos de poliuretano dispuestos en una placa Petri de 10 cm de diámetro. Se aplicaron los extractos a los discos y se midió la superficie de disco comida por diez adultos recién emergidos de S. scolytus durante 24 h. Se ensayaron diez U. minor, dos U. laevis, seis U. glabra, tres híbridos holandeses (europeo x asiático) y un U. pumila en diversas comparaciones. Los discos con extractos de ambos U. laevis fueron significativamente menos comidos que aquéllos con los de U. pumila o de U. minor. Igualmente, los extractos de todos los U. glabra recibieron menor alimentación que aquéllos de U. minor. Por el contrario, S. scolytus no mostró preferencias entre los extractos de U. minor y de U. pumila, e igualmente, entre los de U. minor y los de híbridos holandeses. Nuevamente, los escolítidos prefirieron alimentarse menos de los extractos de U. laevis que de los híbridos holandeses. Se encontraron diferencias intraespecíficas significativas en U. minor. Uno de los clones de U. minor resultó menos preferido cuando se le comparó con otros cuatro árboles. Los extractos de un U. minor moribundo recibieron mayor alimentación que los de un árbol sano. Se realizaron comparaciones entre los extractos del floema de ramillas de 2 a 4 años de edad y de ramillas del año en curso de un mismo árbol. En uno de cuatro U. minor ensayados se observó una preferencia significativa por los extractos de las ramillas más viejas

    Neutron-Capture elements in planetary nebulae: first detections of near-Infrared [Te III] and [Br V] emission lines

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    We have identified two new near-infrared emission lines in the spectra of planetary nebulae (PNe) arising from heavy elements produced by neutron capture reactions: [Te III] 2.1019 μ\mum and [Br V] 1.6429 μ\mum. [Te III] was detected in both NGC 7027 and IC 418, while [Br V] was seen in NGC 7027. The observations were obtained with the medium-resolution spectrograph EMIR on the 10.4m Gran Telescopio Canarias at La Palma, and with the high-resolution spectrograph IGRINS on the 2.7m Harlan J. Smith telescope at McDonald Observatory. New calculations of atomic data for these ions, specifically A-values and collision strengths, are presented and used to derive ionic abundances of Te2+^{2+} and Br4+^{4+}. We also derive ionic abundances of other neutron-capture elements detected in the near-infrared spectra, and estimate total elemental abundances of Se, Br, Kr, Rb, and Te after correcting for unobserved ions. Comparison of our derived enrichments to theoretical predictions from AGB evolutionary models shows reasonable agreement for solar metallicity progenitor stars of \sim2 - 4 M_{\odot}. The spectrally-isolated [Br V] 1.6429 μ\mum line has advantages for determining nebular Br abundances over optical [Br III] emission lines that can be blended with other features. Finally, measurements of Te are of special interest because this element lies beyond the first peak of the s-process, and thus provides new leverage on the abundance pattern of trans-iron species produced by AGB stars.Comment: 9 pages, 1 figure, 4 tables. Accepted for publication in ApJ Letter

    Effects of human versus mouse leukemia inhibitory factor on the in vitro development of bovine embryos

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    Leukemia inhibitory factor (LIF) is a cytokine that shows conflicting effects on in vitro produced (IVP) bovine embryos. Bovine LIF (bLIF) has been cloned and used in culture, but there is no commercially available bLIF. Thus, researchers use human LIF (hLIF) to supplement the culture medium for bovine embryos because of its greater sequence homology compared to murine LIF (mLIF). We compared the effects of mLIF and hLIF on the development of bovine embryos in culture with the effects described for bLIF. Oocytes were matured and fertilized in vitro and cultured in modified synthetic oviduct fluid with BSA. On Day 6 post-insemination, morulae were cultured for 48 h in the presence of: (1) mLIF, 100 ng ml−1; (2) hLIF, 100 ng ml−1; or (3) no LIF. Reduced blastocyst rates were observed on Day 8 for hLIF at the middle and expanded stages, while mLIF had no effect. In contrast, Day 8 blastocysts showed decreased cell counts both in terms of inner cell mass (ICM) and ICM/total cell proportions in the presence of mLIF, while hLIF had no effect. No changes were seen in trophectoderm (TE) and total cell counts. The increased hatching rates and TE cell counts previously described for bLIF, together with the disparate effects exhibited by hLIF and mLIF during blastocyst formation indicate these compounds are inappropriate to replace bLIF. We recommend that heterospecific LIF should not be used to supplement the culture medium for bovine embryo or embryonic stem cells

    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

    ESTUDIO DEL PERFORMANCE DE LOS GRUPOS ESTRATÉGICOS EN EL SISTEMA DE FRANQUICIA ESPAÑOL

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    La preocupación por considerar la heterogeneidad en los comportamientos empresariales dentro de un sector de actividad, ha sido uno de los principales motivos para la búsqueda e identificación de grupos estratégicos, generando un debate inagotable en el ámbito de la estrategia empresarial. Sin embargo, esta preocupación no se ha limitado a identificar arquetipos o configuraciones empresariales, sino que también se ha extendido al estudio de posibles diferencias en el rendimiento entre los grupos identificados. En el presente trabajo, intentamos dar respuesta a esta doble preocupación y todo ello centrándonos en el ámbito de la franquicia. Para ello, se ha elaborado una base de datos con el total de cadenas franquiciadoras (664) que en el año 2005 operaban en España. Los resultados obtenidos revelan la existencia de cinco grupos estratégicos (tipos de franquiciadores) perfectamente diferenciados, los cuales son descritos a partir de las variables estratégicas que los definen. Igualmente, se demuestra la existencia de diferencias en los resultados inter-grupales a partir de determinados indicadores de desempeño (ingresos, resultados ordinarios y rentabilidad)

    Green determination of brominated flame retardants and organochloride pollutants in fish oils by vortex assisted liquid-liquid microextraction and gas chromatography-tandem mass spectrometry

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    A "green", simple, and low-cost sample extraction procedure involving the use of a deep eutectic solvent (DES) in a vortex assisted liquid-liquid microextraction (VALLME) technique followed by gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis was developed for the simultaneous determination of different PBDEs congeners and OCPs residues in fish oils. After evaluation of different eutectic mixtures, the extraction parameters (volume of DES, amount of oil sample and extraction time) were optimized by means of experimental design in order to maximise extraction efficiency. The developed method was validated in terms of linearity, accuracy and precision, presenting limits of detection in the low ng g−1 level. Its application in the analysis of five fish oil samples, allowed the detection of all the target analytes at levels up 21.5 ng g−1. Fish oils used in animal feed showed to be more contaminated than fish oils for human consumption.Sara C. Cunha and José O. Fernandes thanks REQUIMTE, FCT Fundação para a Ciência e a Tecnologia) and FEDER through the project UID/ QUI/50006/2013 - POCI/01/0145/FEDER/007265 with financial support from FCT/MEC through national funds and co-financed by FEDER, under the Partnership Agreement PT2020. Sara C. Cunha acknowledges FCT for IF/01616/2015 contract. Angela G. Solaesa acknowledges University of Burgos for her pre-doctoral contract and Iberoamerican Santander Research Grant (2017) for the mobility financial support. Thanks to European Regional Development Fund (ERDF) and Junta de Castilla y León for financial support of project BU055U16

    Tropical Pacific SST influence on seasonal streamflow variability in Ecuador

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    This study presents a basin wide assessment about the spatio-temporal variability of streamflows in Ecuador for the period 1979-2015. The influence of the tropical Pacific sea surface temperature (SST) on stremaflow variariability from February to April (FMA) period, as the months showing maximum stramflow for the wet season in Ecuador, and from the June to August (JJA), correspondign to the dry season, was analysed. First, a long-term trend analysis was carried out by applying the Sen's slope estimator and the Mann-Kendall test to monthly streamflow data from 45 gaging stations located in different basins across Ecuador. While the coastal region showed the highest generalized positive trends from July to January, the results for the Pacific Andean area suggested a strengthening of the seasonality, presenting an overall increase in the streamflow for all months except August, September and October, which showed negative trends. Second, a singular-value decomposition (SVD) was applied in order to find the main coupled variability patterns between the FMA streamflow and the quasi-coetaneous SST (December-February, DJF) and between the JJA streamflow and the coetaneous SST. The results revealed two main coupled modes for DJF SST/FMA streamflow, the first associated with the canonical El Ni\~no and the second with El Ni\~no Modoki. The latter exerted a major influence on FMA streamflow over most of Ecuador. For JJA streamflow, however, the pattern associated with the traditional El Ni\~no was even more relevant. These results establish the foundations for streamflow modelling in Ecuador based on the Pacific SST, showing the strong response of the streamflows to different types of El Ni\~no event

    Occupational Diseases and Perceived Health in Operating Room Nurses : A Multicenter Cross-Sectional Observational Study

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    Background: The surgical environment has multiple factors that could affect nurses' health. The aim was to determine the effects of the working environment of operating room nurses on their health compared to hospitalization nurses. Methods: A sample of operating room nurses and hospitalization nurses were included in the study and participated by filling in a self-report survey containing sociodemographic data items, the validated Nordic and SF12 scales and a list of medical conditions. Results: Three hundred and thirty-one nurses participated in the study. Statistically significant results had obtained for diagnoses of musculoskeletal disorders and contact dermatitis among the operating room nurses. Conclusion/Application to Practice: Continuous training in ergonomics is essential. Moreover, surgical protocols for preventing infection should be revised, optimizing the chlorhexidine content of soaps to reduce the risk of lesions among the surgical staff

    Los hayedos prepirenaicos aragoneses:: fitosociología, fitotopografía y conservación

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    Tras el estudio de los hayedos prepirenaicos aragoneses (provincias de Zaragoza y Huesca), los autores presentan una tabla de más de 50 inventarios correspondiente al Buxo- Fagetum sylvaticae y explican su composición florística, hábitat y fitotopografía. También se dan tres inventarios del Scillo-Fagetum sylvaticae, mucho más localizado en esta región. Por último, se describe su estado de conservación y se dan algunas recomendaciones para su protección.Prepyrenean aragonese beech-forests (Zaragoza and Huesca provinces) were studied during two years. As a result we present a table of the Buxo-Fagetum sylvaticae (56 releves), a widespread community, and comment on its floristical composition and ecology.Also the more isolated beech-forest of the Scillo-Fagetum sylvaticae is here introduced (3 releves). Finally, some ideas for conservation of these forests are also pointed out
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