172 research outputs found

    The Rotation Of The Deep Solar Layers

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    From the analysis of low-order GOLF+MDI sectoral modes and LOWL data (l > 3), we derive the solar radial rotation profile assuming no latitudinal dependance in the solar core. These low-order acoustic modes contain the most statistically significant information about rotation of the deepest solar layers and should be least influenced by internal variability associated with the solar dynamo. After correction of the sectoral splittings for their contamination by the rotation of the higher latitudes, we obtain a flat rotation profile down to 0.2 solar radius.Comment: accepted in ApJ Letters 5 pages, 2 figure

    Methods and application in experimental pharmacology and drug discovery: 2021

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    Searching for new drugs is an expensive and time-consuming process, but it remains vital for the treatment of many old and new diseases. The availability of current advanced technologies has led to an acceleration of the drug discovery process, facilitating further development of personalized therapies. Sometimes, to obtain the desired therapeutic goals, the drug administration strategy can be of primary importance. Equally important, however, is the understanding of the complex mechanisms of action of new drugs on different cellular and molecular targets, both when the drugs are used alone and when they are administered in combination with other molecules

    Effects of Uniform and Differential Rotation on Stellar Pulsations

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    We have investigated the effects of uniform rotation and a specific model for differential rotation on the pulsation frequencies of 10 \Msun\ stellar models. Uniform rotation decreases the frequencies for all modes. Differential rotation does not appear to have a significant effect on the frequencies, except for the most extreme differentially rotating models. In all cases, the large and small separations show the effects of rotation at lower velocities than do the individual frequencies. Unfortunately, to a certain extent, differential rotation mimics the effects o f more rapid rotation, and only the presence of some specific observed frequencies with well identified modes will be able to uniquely constrain the internal rotation of pulsating stars.Comment: 33 pages, 16 figures. Accepted for publication in Ap

    Detecting individual gravity modes in the Sun: Chimera or reality?

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    Over the past 15 years, our knowledge of the interior of the Sun has tremendously progressed by the use of helioseismic measurements. However, to go further in our understanding of the solar core, we need to measure gravity (g) modes. Thanks to the high quality of the Doppler-velocity signal measured by GOLF/SoHO, it has been possible to unveil the signature of the asymptotic properties of the solar g modes, thus obtaining a hint of the rotation rate in the core. However, the quest for the detection of individual g modes is not yet over. In this work, we apply the latest theoretical developments to guide our research using GOLF velocity time series. In contrary to what was thought till now, we are maybe starting to identify individual low-frequency g modes...Comment: Highlight of Astronomy (HoA) proceedings of the JD-11, IAU 2009. 2 pages, 1 figur

    Characterization of the distribution of water vapour for DInSAR studies on the volcanic island of Tenerife, Canary Islands

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    Measurements of ground displacement have been carried out on the entire active volcanic island of Tenerife, Canary Islands, by means of classical and advanced DInSAR techniques. The main limiting factor on the accuracy of DInSAR measurements is the distribution of the water vapour in the lower troposphere. Hence, it is yet necessary to perform a detailed spatial and temporal characterization of water vapour to understand, and to be able to carry out a direct computation of, the effect of the tropospheric delay on DInSAR results. In this sense, satellite and balloon data have been analysed to infer the variability in the distribution of water vapour and hence, the robustness of DInSAR results on the island of Tenerife.Peer reviewe

    Enhancement of Growth and Grain Yield of Rice in Nutrient Deficient Soils by Rice Probiotic Bacteria

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    Plant associated bacteria are promising alternatives to chemical fertilizers for plant growth and yield improvement in an eco-friendly manner. In this study, rice associated bacteria were isolated and assessed for mineral phosphate solubilizationand indole-3-acetic acid (IAA) production activity in vitro. Six promising strains, which were tentatively identified as phylotaxon Pseudochrobactrum sp. (BRRh-1), Burkholderia sp. (BRRh-2), Burkholderia sp. (BRRh-3), Burkholderia sp. (BRRh-4), Pseudomonas aeruginosa (BRRh-5 and BRRh-6) based on their 16S rRNA gene phylogeny, exhibited significant phosphate solubilizing activity in National Botanical Research Institute phosphate growth medium, and BRRh-4 displayed the highest phosphate solubilizing activity, followed by BRRh-5. The pH of the culture broth declined, resulting in increase of growth rate of bacteria at pH 7, which might be due to organic acid secretion by the strains. In presence of L-tryptophan, five isolates synthesized IAA and the maximum IAA was produced by BRRh-2, followed by BRRh-1. Application of two most efficient phosphate solubilizing isolates BRRh-4 and BRRh-5 by root dipping (colonization) of seedling and spraying at the flowering stage significantly enhanced the growth and grain yield of rice variety BRRI dhan-29. Interestingly, application of both strains with 50% of recommended nitrogen, phosphorus and potassium fertilizers produced equivalent or higher grain yield of rice compared to the control grown with full recommended fertilizer doses, which suggests that these strains may have the potential to be used as bioinoculants for sustainable rice production

    Prospects for studying the solar CNO cycle by means of a lithium neutrino detector

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    Lithium detectors have a high sensitivity to CNO neutrinos from the Sun. The present experimental data and prospects for future experiments on the detection of CNO neutrinos are discussed. A nonstationary case is considered when the flux of 13N neutrinos is higher than the standard solar model predicts due to the influx of fresh material from the peripheral layers to the solar core.Comment: 12 pages, 5 figures, a thoroughly revised version, reported at International Symposium "Physics of Massive Neutrinos" at MILOS (Greece) 19-23 May 200
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