1,616 research outputs found
New insights into volcanic processes at Stromboli from Cerberus, a remote-controlled open-path FTIR scanner system
The ordinary, low intensity, activity of Stromboli volcano is sporadically interrupted by more energetic events termed, depending on their intensity, âmajor explosionsâ and âparoxysmsâ. These short-lived energetic episodes represent a potential risk to visitors to the highly accessible summit of Stromboli. Observations made at Stromboli over the last decade have shown that the composition of gas emitted from the summit craters may change prior to such explosions, allowing the possibility that such changes may be used to forecast these potentially dangerous events.
In 2008 we installed a novel, remote-controlled, open-path FTIR scanning system called Cerberus at the summit of Stromboli, with the objective of measuring gas compositions from individual vents within the summit crater terrace of the volcano with high temporal resolution and for extended periods. In this work we report the first results from the Cerberus system, collected in August-September 2009, November 2009 and May-June 2010.
We find significant, fairly consistent, intra-crater variability for CO2/SO2 and H2O/CO2 ratios, and relatively homogeneous SO2/HCl ratios. In general, the southwest crater is richest in CO2, and the northeast crater poorest, while the central crater is richest in H2O. It thus appears that during the measurement period the southwest crater had a somewhat more direct connection to a primary, deep degassing system; whilst the central and northeast craters reflect a slightly more secondary degassing nature, with a supplementary, shallow H2O source for the central crater, probably related to puffing activity. Such water-rich emissions from the central crater can account for the lower crystal content of its eruption products, and emphasise the role of continual magma supply to the shallowest levels of Stromboli's plumbing system.
Our observations of heterogeneous crater gas emissions and high H2O/CO2 ratios do not agree with models of CO2-flushing, and we show that simple depressurisation during magma ascent to the surface is a more likely model for H2O loss at Stromboli. We highlight that alternative explanations other than CO2 flushing are required to explain distributions of H2O and CO2 amounts dissolved in melt inclusions.
We detected fairly systematic increases in CO2/SO2 ratio some weeks prior to major explosions, and some evidence of a decrease in this ratio in the days immediately preceding the explosions, with periods of low, stable CO2/SO2 ratios between explosions otherwise. Our measurements, therefore, confirm the medium term (~ weeks) precursory increases previously observed with MultiGas instruments, and, in addition, reveal new, short-term precursory decreases in CO2/SO2 ratios. immediately prior to the major explosions. Such patterns, if shown to be systematic, may be of great utility for hazard management at Stromboli's summit.
Our results suggest that intra-crater CO2/SO2 variability may produce short-term peaks and troughs in CO2/SO2 time series measured with in-situ MultiGas instruments, due simply to variations in wind direction
New findings on asteroid spin-vector distributions
Abstract The number of known spin vectors of main belt and near-Earth asteroids is regularly growing, including new objects, and updating the estimates concerning known cases, with the aid of new observations and of improved observational techniques. A reliable statistical analysis of the spin vectors is now possible. In general the poles (both for MB bodies and for NEAs) are not isotropically distributed, as some general theoretical considerations may predict. Main belt asteroids show a lack of poles close to the ecliptic plane. There is a marginally significant excess of prograde spinners in the 100-150 km size range, but interestingly there is not a statistically significant excess in the larger size range. Among NEAs, there is an excess of retrograde rotations. The distributions of longitudes of poles of both groups do not show statistically significant deviations from random. We discuss the possible physical implications of the various resulting pole anisotropies in terms of dynamical-mainly non-gravitational-effects, and point out the importance of new observational campaigns, mainly devoted to compute the poles of small bodies and of the members of asteroid dynamical families
An unloading foam model to constrain Etnaâs 11â13 January 2011 lava fountaining episode
The 11â13 January 2011 eruptive episode at Etna volcano occurred after several months
of increasing ash emissions from the summit craters, and was heralded by increasing
SO2 output, which peaked at âŒ5000 megagrams/day several hours before the start of the
eruptive activity. The eruptive episode began with a phase of Strombolian activity from a pit
crater on the eastern flank of the SEâCrater. Explosions became more intense with time
and eventually became transitional between Strombolian and fountaining, before moving
into a lava fountaining phase. Fountaining was accompanied by lava output from the lower
rim of the pit crater. Emplacement of the resulting lava flow field, as well as associated lava
fountainâ and Strombolianâphases, was tracked using a remote sensing network comprising
both thermal and visible cameras. Thermal surveys completed once the eruptive episode
had ended also allowed us to reconstruct the emplacement of the lava flow field. Using a high
temporal resolution geostationary satellite data we were also able to construct a detailed
record of the heat flux during the fountainâfed flow phase and its subsequent cooling. The
dense rock volume of erupted lava obtained from the satellite data was 1.2 Ă 106 m3; this
was emplaced over a period of about 6 h to give a mean output rate of âŒ55 m3 sâ1. By
comparison, geologic data allowed us to estimate dense rock volumes of âŒ0.85 Ă 106 m3
for the pyroclastics erupted during the lava fountain phase, and 0.84â1.7 Ă 106 m3 for
lavas erupted during the effusive phase, resulting in a total erupted dense rock volume of
1.7â2.5 Ă 106 m3 and a mean output rate of 78â117 m3 sâ1. The sequence of events and
quantitative results presented here shed light on the shallow feeding system of the volcano
High-density neutrophils in MGUS and multiple myeloma are dysfunctional and immune-suppressive due to increased STAT3 downstream signaling
To understand neutrophil impairment in the progression from MGUS through active MM, we investigated the function of mature, high-density neutrophils (HDNs), isolated from peripheral blood. In 7 MM, 3 MGUS and 3 healthy subjects by gene expression profile, we identified a total of 551 upregulated and 343 downregulated genes in MM-HDN, involved in chemokine signaling pathway and FC-gamma receptor mediated phagocytosis conveying in the activation of STAT proteins. In a series of 60 newly diagnosed MM and 30 MGUS patients, by flow-cytometry we found that HDN from MM, and to a lesser extend MGUS, had an up-regulation of the inducible FcÎłRI (also known as CD64) and a down-regulation of the constitutive FcÎłRIIIa (also known as CD16) together with a reduced phagocytic activity and oxidative burst, associated to increased immune-suppression that could be reverted by arginase inhibitors in co-culture with lymphocytes. In 43 consecutive newly-diagnosed MM patients, who received first-line treatment based on bortezomib, thalidomide and dexamethasone, high CD64 could identify at diagnosis patients with inferior median overall survival (39.5 versus 86.7 months, p = 0.04). Thus, HDNs are significantly different among healthy, MGUS and MM subjects. In both MGUS and MM neutrophils may play a role in supporting both the increased susceptibility to infection and the immunological dysfunction that leads to tumor progression
Major eruptive style changes induced by structural modifications of a shallow conduit system: the 2007â2012 Stromboli case
Stromboli is known for its mild, persistent explosive
activity from the vents located within the summit crater
depression at the uppermost part of the Sciara del Fuoco (SdF)
depression. Effusive activity (lava flows) at this volcano normally
occurs every 5â15 years, involving often the opening of
eruptive fissures along the SdF, and more rarely overflows
from the summit crater. Between the end of the 2007 effusive
eruption and December 2012, the number of lava flows inside
and outside the crater depression has increased significantly,
reaching a total of 28, with an average of 4.8 episodes per year.
An open question is why this activity has become so frequent
during the last 6 years and was quite rare before. In this paper,
we describe this exceptional activity and propose an interpretation
based on the structural state of the volcano, changed
after the 2002â2003 and even more after the 2007 flank
effusive eruption. We use images from the Stromboli fixed
cameras network, as well as ground photos, plume SO2 and
CO2 fluxes released by the summit crater, and continuous
fumarole temperature recording, to unravel the interplay
between magma supply, structural and morphology
changes, and lava flow output. Our results might
help forecast the future behaviour and hazard at
Stromboli and might be applicable to other openconduit
volcanoes.partially supported by the Project
INGV-DPC Paroxysm V2/03, 2007â2009 funded by the Istituto
Nazionale di Geofisica e Vulcanologia and the Italian Civil ProtectionPublished8413V. Dinamiche e scenari eruttiviJCR Journalrestricte
Exceptional eruptive CO2 emissions from intra-plate alkaline magmatism in the Canary volcanic archipelago
Alkaline mafic magmas forming intra-plate oceanic islands are believed to be strongly enriched in CO2 due to low-degree partial melting of enriched mantle sources. However, until now, such CO2 enhancement has not been verified by measuring CO2 degassing during a subaerial eruption. Here, we provide evidence of highly CO2-rich gas emissions during the 86-day 2021 Tajogaite eruption of Cumbre Vieja volcano on La Palma Island, in the Canary archipelago. Our results reveal sustained high plume CO2/SO2 ratios, which, when combined with SO2 fluxes, melt inclusion volatile contents and magma production rates at explosive and effusive vents, imply a magmatic CO2 content of 4.5 ± 1.5 wt%. The amount of CO2 released during the 2021 eruptive activity was 28 ± 14 Mt CO2. Extrapolating to the volume of alkaline mafic magmas forming La Palma alone (estimated as 4000 km3 erupted over 11 Ma), we infer a maximum CO2 emission into the ocean and atmosphere of 1016 moles of CO2, equivalent to 20% of the eruptive CO2 emissions from a large igneous province eruption, suggesting that the formation of the Canary volcanic archipelago produced a CO2 emission of similar magnitude as a large igneous province
Favorable outcome of SARS-CoV-2 infection in pediatric hematology oncology patients during the second and third pandemic waves in Italy: a multicenter analysis from the Infectious Diseases Working Group of the Associazione Italiana di Ematologia e Oncologia Pediatrica (AIEOP)
COVID-19 has a mild clinical course with low mortality rate in general pediatric population, while variable outcomes have been described in children with cancer. Infectious diseases working party of the AIEOP collected data on the clinical characteristics and outcomes of SARS-CoV-2 infections in pediatric oncology/hematology patients from April 2020 to May 2021, including the second and the third waves of the pandemic in Italy. Factors potentially associated with moderate, severe, or critical COVID-19 were analyzed. Of the 153 SARS-Cov2 infections recorded, 100 were asymptomatic and 53 symptomatic. The course of COVID-19 was mild in 41, moderate in 2, severe in 5, and critical in 5 children. A total of 40.5% of patients were hospitalized, ten requiring oxygen support and 5 admitted to the intensive care unit. Antibiotics and steroids were the most used therapies. No patient died due to SARS-CoV-2 infection. Infections occurring early (< 60 days) after the diagnosis of the underlying disease or after SCT were associated to moderate, severe, and critical disease compared to infections occurring late (> 60 days) or during maintenance therapy. In the patients on active chemotherapy, 59% withdrew the treatment for a median of 15 days. SARS-CoV-2 presented a favorable outcome in children with cancer in Italy during the pandemic. Modification of therapy represents a major concern in this population. Our findings suggest considering regular chemotherapy continuation, particularly in patients on maintenance therapy or infected late after the diagnosis
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