86,847 research outputs found
Testing protoplanetary disc dispersal with radio emission
No full textWe consider continuum free–free radio emission from the upper atmosphere of protoplanetary discs as a probe of the ionized luminosity impinging upon the disc. Making use of previously computed hydrodynamic models of disc photoevaporation within the framework of extreme-ultraviolet (EUV) and X-ray irradiation, we use radiative transfer post-processing techniques to predict the expected free–free emission from protoplanetary discs. In general, the free–free luminosity scales roughly linearly with ionizing luminosity in both EUV- and X-ray-driven scenarios, where the emission dominates over the dust tail of the disc and is partial optically thin at cm wavelengths. We perform a test observation of GM Aur at 14–18?GHz and detect an excess of radio emission above the dust tail to a very high level of confidence. The observed flux density and spectral index are consistent with free–free emission from the ionized disc in either the EUV- or the X-ray-driven scenario. Finally, we suggest a possible route to testing the EUV- and X-ray-driven dispersal model of protoplanetary discs, by combining observed free–free flux densities with measurements of mass-accretion rates. On the point of disc dispersal one would expect to find an M?2? scaling with free–free flux in the case of EUV-driven disc dispersal or an ?* scaling in the case of X-ray-driven disc dispersa
Immagini degli strumenti scrittori dalle Antichità di Ercolano
No full textThe present paper aims at describing the ancient paintings published in the Antichità di
Ercolano, which contain instrumenta scriptoria, in order to offer a small contribution to the history
of ancient books
Immagini degli strumenti scrittori dalle ‘Antichità di Ercolano'
No full textThe present paper aims at describing the ancient paintings published in the Antichità di
Ercolano, which contain instrumenta scriptoria, in order to offer a small contribution to the history
of ancient books
Ionization-induced star formation - IV. Triggering in bound clusters
No full textWe present a detailed study of star formation occurring in bound star-forming clouds under the influence of internal ionizing feedback from massive stars across a spectrum of cloud properties. We infer which objects are triggered by comparing our feedback simulations with control simulations in which no feedback was present. We find that feedback always results in a lower star formation efficiency and usually but not always results in a larger number of stars or clusters. Cluster mass functions are not strongly affected by feedback, but stellar mass functions are biased towards lower masses. Ionization also affects the geometrical distribution of stars in ways that are robust against projection effects, but may make the stellar associations more or less subclustered depending on the background cloud environment. We observe a prominent pillar in one simulation which is the remains of an accretion flow feeding the central ionizing cluster of its host cloud and suggest that this may be a general formation mechanism for pillars such as those observed in M16. We find that the association of stars with structures in the gas such as shells or pillars is a good but by no means foolproof indication that those stars have been triggered and we conclude overall that it is very difficult to deduce which objects have been induced to form and which formed spontaneously simply from observing the system at a single time.Peer reviewe
“A Decision Support System for Cultural Heritage Programming: the Case of Great Program for Historic Center of Naples”
No full textSocial capital, quality of institutions and lockdown. Evidence from Italian provinces
No full textThis paper uses the exogenous shock generated by the COVID-19 pandemic and the relative government response as an informative case in investigating the factors able to affect policy efficacy. Lockdown measures have been widely adopted to limit the diffusion of COVID-19, indirectly supporting the capacity of the hospital system to face the pandemic. Lockdown obliges people to change their social behaviour significantly, and consequently is a matter of serious concern amongst the population. For this reason, how people react to lockdown is of the utmost importance, since failure to observe it properly will be of little benefit in reducing contagion. In this rationale, factors correlated with individuals' behaviour could affect the efficacy of such measures. The aim of this paper is to investigate whether differences in institutional quality and social capital are correlated with the efficacy of lockdown measures, taking the Italian provinces as a case study. Using a quantitative analysis employing F-GLS estimators, our results suggest that both local social capital and institutional quality have affected the efficiency of lockdown measures in Italian provinces. In general terms these factors contribute to forming the set of incentives able to promote individual behaviour that is in closer compliance with government choices. In this perspective, institutional quality and social capital can be considered factors able to influence the efficacy of policies
Potato R1 resistance gene confers resistance against Phytophthora infestans in transgenic tomato plants
No full textTomato is challenged by several pathogens which cause loss of production. One such pathogen is the oomycete Phytophthora infestans which is able to attack all the aerial parts of the plant. Although a wide range of resistance sources are available, genetic control of this disease is not yet successful. Pyramiding R-genes through genetic transformation could be a straightforward way to produce tomato and potato lines carrying durable resistance to P. infestans. In this work the R1 potato gene was transferred into tomato lines. The tomato transgenic lines were analyzed by using q-RT-PCR and progeny segregation to determine the gene copy number. To test the hypothesis that R1 represents a specifically regulated R-gene, transgenic tomato plants were inoculated with P. infestans isolate 88133 and IPO. All the plants containing the R1 gene were resistant to the late blight isolate IPO-0 and susceptible to isolate 88133. These results provide evidence for specific activation of the R1 gene during pathogen challenge. Furthermore, evidence for enhancement of PR-1 gene expression during P. infestans resistance response was obtained
Ferriello F., Formisano G., Paparo R., De Martino M., Frusciante L.,Ercolano M.R. Molecular Marker Assisted Selection To Introduce Disease Resistance Genes In Traditional Tomato Varieties. Poster Abstact A 30 /Proceedings Of The 52nd Italian Society Of Agricultural Genetics Annual Congress Padova, Italy 14/17 September, 2008 /Isbn 978-88-900622-8-5
No full text
Evaluation of combining ability in Cucurbita pepo L. and Cucurbita moschata Duchesne accessions for fruit and seed quantitative traits
No full textA complete diallel cross study of seven Iranian accessions of Cucurbita, including five C. pepo (four naked seed and one true seed type) and two C. moschata accessions, was carried out during two planting seasons at University of Tehran, Karaj, Iran. Investigated traits were fruit number, fruit yield, seed yield, fruit weight, seed weight, ratio of fruit weight/seed weight, 100 seeds weight and seed number. ANOVA for all of the characteristics except fruit number indicated significant differences among the genotypes. Analysis of variance of the diallel data set also revealed high and significant effects of general (GCA) and specific combining ability (SCA) between genotypes in respect of fruit yield, seed yield, seed weight, ratio of fruit weight/seed weight and seed number. The GCA of fruit weight and seed weight and the SCA of 100 seeds weight were significant. The reciprocal effects were significant for all the measured traits. Heritability in broad (h2 b) and narrow (h2 n) estimates were generally high for fruit yield, seed yield, seed weight, fruit weight/seed weight and seed number, while they were low for fruit weight and 100 seeds weight. Favourable heterosis over the best parent was found for fruit yield, fruit weight and 100 seeds weigh
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