Search results for "STELLA"
showing 10 items of 1995 documents
The Gaia-ESO Survey: evidence of atomic diffusion in M67?
2018
Investigating the chemical homogeneity of stars born from the same molecular cloud at virtually the same time is very important for our understanding of the chemical enrichment of the interstellar medium and with it the chemical evolution of the Galaxy. One major cause of inhomogeneities in the abundances of open clusters is stellar evolution of the cluster members. In this work, we investigate variations in the surface chemical composition of member stars of the old open clusterM67 as a possible consequence of atomic diffusion effects taking place during the main-sequence phase. The abundances used are obtained from high-resolution UVES/FLAMES spectra within the framework of the Gaia-ESO S…
Mitigation of the impact of stellar activity on observations of transiting planets
2023
La tesi si concentra sulla quantificazione dell'impatto dell'attività stellare sulle osservazioni dei pianeti in transito e sull'identificazione di una metodologia per correggere questi effetti. In particolare, viene approfondito l'effetto delle macchie stellari, sia non occultate che occulte. La presenza di macchie sul disco stellare visibile può distorcere la curva della luce di transito primaria in modo dipendente dalla lunghezza d'onda, mimando la presenza di un'atmosfera. Per tener conto di questo effetto, la tesi presenta un metodo innovativo per stimare le proprietà delle macchie e la loro distribuzione dalle osservazioni fuori transito e, su questa base, correggere le curve di luce …
Contribution of observed multi frequency spectrum of Alfvén waves to coronal heating
2019
Context. Whilst there are observational indications that transverse magnetohydrodynamic (MHD) waves carry enough energy to maintain the thermal structure of the solar corona, it is not clear whether such energy can be efficiently and effectively converted into heating. Phase-mixing of Alfvén waves is considered a candidate mechanism, as it can develop transverse gradient where magnetic energy can be converted into thermal energy. However, phase-mixing is a process that crucially depends on the amplitude and period of the transverse oscillations, and only recently have we obtained a complete measurement of the power spectrum for transverse oscillations in the corona. Aims. We aim to investig…
Solar Coronal Loops Associated with Small-scale Mixed Polarity Surface Magnetic Fields
2017
L. P. Chitta et. al.
Critical reading of some papers related to the Bibracte basin
2021
Since its discovery in 1987, the monumental basin of Bibracte questions archeologists because of its atypical orientation that was thought not to follow the way on which it lies. We study 4 archeoastronomical papers dealing with the orientation of the short and long axes on the sun rise at winter solstice or on peculiar stars and we discuss the validity of these hypotheses.
Assessing the use of the mitochondrial cox1 marker for use in DNA barcoding of red algae (Rhodophyta)
2011
The red algae, a remarkably diverse group of organisms, are difficult to identify using morphology alone. Following the proposal to use the mitochondrial cytochrome c oxidase subunit 1 (cox1) for DNA barcoding animals, we assessed the use of this, ne in the identification of red algae using 48 samples plus 31 sequences obtained from GenBank. The data set spanned six gene orders of red algae: the Bangiales, Ceramiales, Corallinales, Gigartinales, Gracilariales and Rhodymeniales. The results indicated that species could be discriminated. Intraspecific variation was between 0 and 4 bp over 539 bp analyzed except in Mastocarpus stellatus (0-14 bp) and Gracilaria gracilis (0-11 bp). Cryptic dive…
Sparassidae from Japan. II. First Pseudopoda species and new Sinopoda species (Araneae: Sparassidae: Heteropodinae)
2002
The genus Pseudopoda is recorded for the first time from Japan. Pseudopoda kasariana sp. nov. (_??_, _??_) and Pseudopoda spirembolus sp. nov. (_??_, _??_) are described from Amami-oshima Island and Okinawajima Island respectively. Four new Sinopoda species are described: Sinopoda albofasciata (_??_), Sinopoda derivata (_??_, _??_), Sinopoda ogatai (_??_, _??_) and Sinopoda stellatops (_??_, _??_). Sinopoda koreana (Paik 1968) is recorded for the first time from Japan. New records of Sinopoda okinawana Jager & Ono 2000 and S. tanikawai Jager & Ono 2000 are presented. Within the genus Sinopoda Jager 1999 the okinawana species-group is newly diagnosed, which is represented by S. albofasciata …
Bases de la resistencia a preparados bioinsecticidas basados en "Bacillus thuringiensis" en diferentes especies de insectos
2015
El empleo de insecticidas en la agricultura moderna resulta fundamental para obtener unos niveles óptimos de productividad. Actualmente se tiende al empleo de bioinsecticidas dados los efectos perniciosos de la mayor parte de los insecticidas convencionales. Los preparados bioinsecticidas basados en las proteínas cristalinas insecticidas (toxinas Cry) de “Bacillus thuringiensis” (Bt) son los de mayor venta del mercado y las plantas transgénicas protegidas por estas proteínas, están siendo cultivadas a escala mundial. La vida útil de este bioinsecticida podría verse limitada por la aparición de poblaciones de insectos resistentes si no se adoptan las medidas oportunas de manejo de resistenci…
Computer vision and thermal monitoring of HMPE fibre rope condition during CBOS testing
2020
Abstract Fibre rope usage in deep sea lifting operations is gaining more prominence in recent times. With rope minimum break loads (MBL) comparable to that of their steel wire counterparts, the use of high modulus polyethylene (HMPE) ropes is seen as a viable option for use in subsea construction cranes. The ropes are worn out during use and visual inspection remains one of the main methods of determining whether a fibre rope is to be retired from use, therefore a natural extension is condition monitoring through computer vision. Creep and temperature are constraining with HMPE ropes and should be monitored continuously, particularly when the rope is cyclically bent over sheaves. Additional…
The Impact of Solar Penetration on Solar and Gas Market Value: An Application to the Italian Power Market
2014
We assess the impact of solar penetration in the Italian wholesale electricity market on the market value of solar with respect to gas sources, measured as the ratio between the relative price they respectively earn and the average daily electricity price (value factor). We find that, on average, an increase of solar generation has a negative impact on the price earned by solar producers, thus causing a marginal departure from the grid parity condition. The relation between solar production and its market value is not constant over the years, while it depends on the degree of solar penetration. It is positive for very low levels of solar production while, as production increases, its margin…