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  • 1
    Publication Date: 2020-11-09
    Description: After the large scale event of Neapolitan Yellow Tuff (~15 kyr BP), intense and mostly explosive volcanism has occurred within and along the boundaries of the Campi Flegrei caldera. Eruptions occurred closely spaced in time, over periods from a few centuries to a few millennia, and were alternated by periods of quiescence lasting even several millennia. Sometimes events also occurred closely in space thus generating a cluster of events. The most recent Monte Nuovo eruption occurred in 1538 AD after more than about 2.7 kyr from the previous one. Unfortunately, there is a remarkable uncertainty on the eruptive record, affecting the time of eruptions, location of vents as well as the erupted volume estimates. This study has the purpose of modelling such uncertainty by using a quantitative probabilistic model and obtaining quantitative estimates about the temporal and spatial distribution of the volcanism. In particular, the study adopts a time-space double stochastic Poisson-type model with a local self-exciting feature able to produce clustering events that are consistent with the reconstructed observed pattern at Campi Flegrei. Results allow to estimate the temporal eruptive base-rate of the caldera as well as its capacity to generate clusters of events. In particular the effect of the Monte Nuovo event on a possible reactivation of the system has been investigated. The analysis allows also to discriminate between the initial and main part of the eruptive epochs as well as to investigate the different behaviour of the eastern and western sectors of the caldera.
    Description: Published
    Description: Prague (CZ)
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Keywords: Campi flegrei caldera ; temporal modeling
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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  • 2
    Publication Date: 2020-11-09
    Description: Campi Flegrei (CF) is a densely urbanized caldera with a very high volcanic risk. Its more recent volcanic activity was characterized in the last 15 kyrs by more than 70 explosive events of variable scale and vent location. The sequence of eruptive events at CF is remarkably inhomogeneous, both in space and time. Eruptions concentred over periods from a few centuries to a few millennia, and were alternated by periods of quiescence lasting up to several millennia. As a consequence, activity has been subdivided into three distinct epochs, i.e. Epoch I, 15- 9.5 kyrs, Epoch II, 8.6 - 8.2 kyrs, and Epoch III, 4.8 - 3.7 kyrs BP [e.g. Orsi et al., 2004; Smith et al., 2011]. The eruptive record also shows the presence of clusters of events in space-time, i.e. the opening of a new vent in a particular location and at a specific time seems to increase the probability of another vent opening in the nearby area and in the next decades-centuries (self-exciting effect). Probabilistic vent opening mapping conditional the occurrence of a new event and able to account for some of the intrinsic uncertainties affecting the system, has been investigated in some recent studies [e.g. Selva et al. 2011, Bevilacqua et al. 2014, in preparation], but a spatial-temporal model of the sequence of volcanic activity remains an open issue. Hence we have developed a time-space mathematical model that takes into account both the self-exciting behaviour of the system and the significant uncertainty affecting the eruptive record. Based on the past eruptive record of the volcano, the model allows to simulate sequences of future events as well as to better understand the spatial and temporal evolution of the system. In addition, based on the assumption that the last eruptive event occurred in 1538 AD (Monte Nuovo eruption) is the first event of a new epoch of activity, the model can estimate the probability of new vent opening at CF in the next decades.
    Description: Published
    Description: San Francisco (CA)
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Keywords: Campi flegrei caldera ; temporal modeling
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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  • 3
    ISSN: 1617-4623
    Keywords: Bleomycin ; Cysteamine ; WR-1065 ; Saccharomyces ; Antimutagens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cancer chemotherapy drug bleomycin (BLM) is a potent inducer of genetic damage in a wide variety of assays. The radioprotectors cysteamine (CSM) and WR-1065 have been shown in previous studies to potentiate the induction of micronuclei and chromosome aberrations by BLM in Go human lymphocytes. By contrast, WR-1065 is reported to reduce the induction of hprt mutations by BLM in Chinese hamster cells. To elucidate the basis for these interactions, we examined the effects of CSM and WR-1065 on the induction of mitotic gene conversion by BLM in the yeast Saccharomyces cerevisiae. Treatment with BLM causes a dose-dependent increase in the frequency of mitotic gene conversion and gene mutations. Unlike its potentiation of BLM in G0 lymphocytes, WR-1065 protected against the recombinagenicity of BLM in yeast. CSM was also strongly antirecombinagenic under some conditions., but the nature of the interaction depended strongly on the treatment conditions. Under hypoxic conditions, cysteamine protected against BLM, but under oxygenrich conditions CSM potentiated the genetic activity og BLM. The protective effect of aminothiols against BLM may be ascribed to the depletion of oxygen required for the activation of BLM and the processing of BLM-induced damage. Aminothiols may potentiatc the effect of BLM by acting as an electron source for the activation of BLM and/or by causing conformational alterations that make DNA more accessible tc BLM. The results indicate that aminothiols have a strong modulating influence on the genotoxicity of BLM in yeast as they do in other genetic assays. Moreover, the modulation differs markedly depending on physiological conditions. Thus, yeast assays help to explain why aminothiols have been observed to potentiate BLM in some genetic systems and to protect against it in others.
    Type of Medium: Electronic Resource
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