Timescales of mingling in shallow magmatic reservoirs

Arrival of magma from depth into shallow reservoirs has been documented as one of the possible processes leading to eruption. Magma intruding and rising to the surface interacts with the already emplaced, degassed magmas residing at shallower depths, leaving chemical signatures in the erupted products.We performed two-dimensional numerical simulations of the arrival of gas- rich magmas into shallow reservoirs. We solve the fluid dynamics for the two interacting magmas, evaluating the space–time evolution of the physical properties of the mixture. Convection and mingling develop quickly into the chamber and feeding conduit/dyke, leading on longer timescales to a density stratification with the lighter, gas-richer magma, mixed with different proportions of the resident magma, rising to the top of the chamber due to buoyancy. Over timescales of hours, the magmas in the reservoir appear to have mingled throughout, and convective patterns become harder to identify. Our simulations have been performed changing the geometry of the shallow reservoir and the gas content of the initial end-member magmas. Horizontally elongated magma chambers, as well as higher density contrasts between the two magmas, cause faster ascent velocities and also increase the mixing efficiency

UNDERSTANDING CHEMICAL ALLERGEN POTENCY: CONTRIBUTION OF KERATINOCYTES

Repeated exposure to chemical allergens increases the risk of becoming sensitized. Once an individual has become sensitized, any following exposure to the same chemical may result in allergic contact dermatitis (ACD). The risk to develop ACD is considered a serious health issue and the identification of potential sensitizing agents within consumer products is therefore crucial. With the enforcement of the 7th Amendment to the EU Cosmetics Directive (76/768/EEC) in March 2013, currently known as the Cosmetics Regulation (EU 1223/2009), a ban on the use of animals was introduced for identifying repeated dose toxicity endpoints of chemicals used in cosmetic ingredients and products. This ban results in an urgent need for the development of suitable non-animal methods for safety testing. The development of animal alternatives has become even more urgent due to the Registration, Evaluation, Authorisation and Restriction of CHemicals (REACH) regulation, which may demand toxicity tests for chemicals produced in quantities of over 1 ton per year. Over the last years, many in vitro models have been proposed to identify the potential of chemicals to induce skin sensitization to meet current animal welfare, public opinions and legislation constrains. The development of in vitro, in chemico or in silico models for predicting the sensitizing potential of new chemicals is receiving widespread interest. Keratinocytes (KCs) play a key role in skin sensitization, as they provide the essential danger signals, they are involved in the protein haptenation process, and supply enzymes that are necessary for the metabolic activation of prohapten. Human KCs constitutively express several cytokines, including pro-interleukin (IL)-1\uf061, pro-IL-1\uf062 and pro-IL-18. Evidences provided from our group has shown that IL-18 production in human KCs can be used as a sensitive method to identify contact allergens, discriminating them from respiratory allergens and irritants with a sensitivity of 87%, specificity of 95% and an accuracy of 90%. IL-18 is synthesized as preform, which require proteolytic maturation by cysteine protease caspase-1, which must first be activated by the inflammasome. More recently, we demonstrated the possibility of combining the Reconstituted human Epidermis (RhE) potency assay with the assessment of IL-18 release to provide a single test for identification and classification of skin sensitizing chemicals, including chemicals of low water solubility or stability (Gibbs et al., 2013). In addition to being able to determine whether or not a chemical is a sensitizer (labelling) it is also equally important to determine the potency of a sensitizer (classification) in order to identify a maximum safe concentration for human exposure (risk assessment). The purpose of this thesis was to understand the role of several genes and proteins involved in contact allergen-induced NLRP3 inflammasome activation and IL-18 production, and their possible correlation with allergenic potency. Another objective of this thesis was to extend the list of chemicals tested in the RhE IL-18 potency assay, and to provide a simple method for the in vitro estimation of the expected sensitization induction level. Results obtained during these three years of research activity have shown that several proteins involved in NLRP3 inflammasome activation/regulation were modulated by contact allergens. In particular I focused my attention on the role of NLRP12 and B lymphocyte induced maturation protein-1 (Blimp-1) in IL-18 production. The expression of NLRP3, ASC and caspase-1 activation were investigated by Western blot analysis and the NLRP12 localization characterized by immunoprecipitation. Regarding potency classification the results obtained using RhE IL-18 potency assay are very promising, and further compounds should be tested to better define the applicability and limitation of RhE IL-18 potency test

Probabilistic Volcanic Hazard and Risk Assessment

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Further Testing of an Amine-based Pressure-Swing System for Carbon Dioxide and Humidity Control

In a crewed spacecraft environment, atmospheric carbon dioxide (CO2) and moisture control are crucial. Hamilton Sundstrand has developed a stable and efficient amine-based CO2 and water vapor sorbent, SA9T, that is well suited for use in a spacecraft environment. The sorbent is efficiently packaged in pressure-swing regenerable beds that are thermally linked to improve removal efficiency and minimize vehicle thermal loads. Flows are all controlled with a single spool valve. This technology has been baselined for the new Orion spacecraft. However, more data was needed on the operational characteristics of the package in a simulated spacecraft environment. A unit was therefore tested with simulated metabolic loads in a closed chamber at Johnson Space Center during the last third of 2006. Those test results were reported in a 2007 ICES paper. A second test article was incorporated for a third phase of testing, and that test article was modified to allow pressurized gas purge regeneration on the launch pad in addition to the standard vacuum regeneration in space. Metabolic rates and chamber volumes were also adjusted to reflect current programmatic standards. The third phase of tests was performed during the spring and summer of 2007. Tests were run with a range of operating conditions, varying: cycle time, vacuum pressure (or purge gas flow rate), air flow rate, and crew activity levels. Results of this testing are presented and potential flight operational strategies discussed

The ecosystem carbon sink implications of mountain forest expansion into abandoned grazing land: The role of subsoil and climatic factors

Woody encroachment is a widespread phenomenon resulting from the abandonment of mountain agricultural and pastoral practices during the last century. As a result, forests have expanded, increasing biomass and necromass carbon (C) pools. However, the impact on soil organic carbon (SOC) is less clear. The main aim of this study was to investigate the effect of woody encroachment on SOC stocks and ecosystem C pools in six chronosequences located along the Italian peninsula, three in the Alps and three in the Apennines. Five stages along the chronosequences were identified in each site. Considering the topsoil (0 30 cm), subsoil (30 cm-bedrock) and whole soil profile, the temporal trend in SOC stocks was similar in all sites, with an initial increment and subsequent decrement in the intermediate phase. However, the final phase of the woody encroachment differed significantly between the Alps (mainly conifers) and the Apennines (broadleaf forests) sites, with a much more pronounced increment in the latter case. Compared to the previous pastures, after mature forest (>62 years old) establishment, SOC stocks increased by: 2.1(mean) ± 18.1(sd) and 50.1 ± 25.2 Mg C·ha -1 in the topsoil, 7.3 ± 17.4 and 93.2 ± 29.7 Mg C·ha -1 in the subsoil, and 9.4 ± 24.4 and 143.3 ± 51.0 Mg C·ha -1 in the whole soil profile in Alps and Apennines, respectively. Changes in SOC stocks increased with mean annual air temperature and average minimum winter temperature, and were negatively correlated with the sum of summer precipitation. At the same time, all other C pools (biomass and necromass) increased by 179.1 ± 51.3 and 304.2 ± 67.6 Mg C·ha -1 in the Alps and the Apennines sites, respectively. This study highlights the importance of considering both the subsoil, since deep soil layers contributed 38% to the observed variations in carbon stocks after land use change, and the possible repercussions for the carbon balance of large areas where forests are expanding, especially under pressing global warming scenarios. © 2019 Elsevier B.V.The project of this work is part of the research activities of the PhD in science, technology and biotechnology for sustainability. The first author received a fully founded scholarship partially by the University of Tuscia (Viterbo - Italy) and partially by the University of Molise . Tommaso Chiti participated in the project by conducting his work with the funding obtained through the LIFE MediNet project (grant number LIFE15 PRE IT/732295 ). Jorge Curiel Yuste was financed in part by the Basque Government through the BERC 2018-2021 (grant code) program and by Spanish Ministry of Economy and Competitiveness (MINECO) through BC3 María de Maeztu excellence accreditation MDM-2017-0714. I.C (grant code)

CO2 Flushing Triggers Paroxysmal Eruptions at Open Conduit Basaltic Volcanoes

Open conduit volcanoes erupt with the highest frequency on Earth. Their activity is characterized by an outgassing flux that largely exceeds the gas that could be released by the erupted magma; and by frequent small explosions intercalated by larger events that pose a significant risk to locals, tourists, and scientists. Thus, identifying the signs of an impending larger explosion is of utmost importance for the mitigation of volcanic hazard. Larger explosive events have been associated with the sudden ascent of volatile rich magmas, however, where and why magma accumulates within the plumbing system remains unclear. Here we show that the interaction between CO2-rich fluids and magma spontaneously leads to the accumulation of volatile-rich, low density and gravitationally unstable magma at depth, without the requirement of permeability barriers. CO2-flushing forces the exsolution of water and the increase of magma viscosity, which proceeds from the bottom of the magma column upward. This rheological configuration unavoidably leads to the progressive thickening of a gas-rich and low density (i.e., gravitationally unstable) layer at the bottom of the feeding system. Our calculations account for observations, gas monitoring and petrological data; moreover, they provide a basis to trace the approach to deeply triggered large or paroxysmal eruptions and estimate their size from monitoring data. Our model is finally applied to Stromboli volcano, an emblematic example of open conduit volcano, but can be applied to any other open conduit volcano globally and offers a framework to anticipate the occurrence of unexpectedly large eruptions