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  • 1
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    Anak Krakatau triggers volcanic freezer in the upper troposphere (2020)
    Details
    Publication Date: 2020-05-25
    Description: Volcanic activity occurring in tropical moist atmospheres can promote deep convection and trigger volcanic thunderstorms. These phenomena, however, are rarely observed to last continuously for more than a day and so insights into the dynamics, microphysics and electrification processes are limited. Here we present a multidisciplinary study on an extreme case, where volcanically-triggered deep convection lasted for six days. We show that this unprecedented event was caused and sustained by phreatomagmatic activity at Anak Krakatau volcano, Indonesia during 22-28 December 2018. Our modelling suggests an ice mass flow rate of ~5 × 106 kg/s for the initial explosive eruption associated with a flank collapse. Following the flank collapse, a deep convective cloud column formed over the volcano and acted as a 'volcanic freezer' containing ~3 × 109 kg of ice on average with maxima reaching ~1010 kg. Our satellite analyses reveal that the convective anvil cloud, reaching 16-18 km above sea level, was ice-rich and ash-poor. Cloud-top temperatures hovered around -80 °C and ice particles produced in the anvil were notably small (effective radii ~20 µm). Our analyses indicate that vigorous updrafts (〉50 m/s) and prodigious ice production explain the impressive number of lightning flashes (~100,000) recorded near the volcano from 22 to 28 December 2018. Our results, together with the unique dataset we have compiled, show that lightning flash rates were strongly correlated (R = 0.77) with satellite-derived plume heights for this event.
    Description: Published
    Description: in 3584
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Electronic Resource
    Electronic Resource
    Flow Cytometric Study of Blood Leucocytes in Clinical Forms of Human Schistosomiasis (1997)
    Oxford, UK : Blackwell Science Ltd
    Scandinavian journal of immunology 46 (1997), S. 0 
    Details
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim of this study was to examine three distinct groups of schistosomiasis patients and to determine whether cell phenotype profiles could be correlated with the different clinical forms of the disease. The data obtained indicate that Schistosoma mansoni infected patients have a lower percentage of CD3+ T cells than do non-infected individuals. Interestingly, infected patients presented more than twice the mean percentage of circulating activated T cells (CD3+HLA-DR+) when compared to the control group. Examination of T lymphocyte subpopulations showed that patients with the severe hepatosplenic form (HS) of the disease had lower levels of both CD8High+ and CD8Low+ cells when compared to the other groups of patients. All infected individuals had a higher percentage of circulating B cells, with an increase in the CD5+ B cell population that was more evident in the HS group. The data presented here are evidence to support a relationship between the hepatosplenic form of the disease, a decrease on the CD8+ cell population and an elevation on CD5+B cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3083.1997.d01-119.x
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  • 3
    Electronic Resource
    Electronic Resource
    Cytokine Regulation of Human Immune Response to Schistosoma mansoni: Analysis of the Role of IL-4, IL-5 and IL-10 on Peripheral Blood Mononuclear Cell Responses (1997)
    Oxford, UK : Blackwell Science Ltd
    Scandinavian journal of immunology 46 (1997), S. 0 
    Details
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The role of cytokines on the in vitro proliferative response of peripheral blood mononuclear cells (PBMC) from Schistosoma mansoni infected patients to soluble egg (SEA) and adult worm antigens (SWAP) were evaluated. The results obtained demonstrated that the proliferative response of PBMC from chronic intestinal (INT) patients to SEA and SWAP is increased by the blockage of IL-10 with specific monoclonal antibodies (MAb). The effects of these antibodies were readily reversed by the addition of recombinant IL-10. In contrast, no effect was observed on the PBMC response of acute and hepatosplenic patients (HS) in the presence of anti-IL-10. Anti-IL-4 antibodies decreased the PBMC response of the intestinal (INT) and HS individuals to SEA and SWAP, and the PBMC response of acute patients to SEA but not to SWAP. Addition of anti-IL-5 MAb did not decrease the PBMC response of acute patients to SEA or SWAP. These results suggested that IL-10 has an important role in the modulation of the immune response in chronic asymptomatic patients and that this cytokine may be an important factor in controlling morbidity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3083.1997.d01-136.x
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  • 4
    Electronic Resource
    Electronic Resource
    Immune Response in Human Visceral Leishmaniasis: Analysis of the Correlation Between Innate Immunity Cytokine Profile and Disease Outcome (2005)
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    Scandinavian journal of immunology 62 (2005), S. 0 
    Details
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We investigated the cytokine profile of cells of the innate immune response and its association with active (ACT), asymptomatic (AS) and cured (CUR) human visceral leishmaniasis (VL), as well as noninfected (NI) subjects. The frequency of cytokine-producing cells was determined after short-term in vitro incubation of whole peripheral blood samples with soluble Leishmania antigen (SLA). Our data demonstrated a predominant type 2 cytokine profile in NI and ACT. In NI, we observed an increase of IL-4+ neutrophils, IL-10+ eosinophils besides a decrease of tumour necrosis factor (TNF)-α+ eosinophils/monocytes. Yet in ACT, we observed an increase of IL-4+ neutrophils and natural killer (NK) cells and IL-10+ monocytes, a reduced frequency of IL-12+ and IFN-γ+ eosinophils and lower levels of TNF-α+ and IL-12+ monocytes. AS presented a mixed profile, characterized by an increase of IFN-γ+ neutrophils/eosinophils and NK cells, of IL-12+ eosinophils/monocytes, as well as increase of IL-4+ neutrophils and NK cells and IL-10+ eosinophils/monocytes. In contrast, CUR was characterized by a type 1 response with an increase of IFN-γ+ neutrophils/eosinophils and NK cells, associated with an increase in IL-12+ monocytes. In conclusion, we show a correlation between innate immune cytokine patterns and clinical status of VL, suggesting that these cells, in addition to other factors, may contribute to the cytokine microenvironment in which Leishmania-specific T cells are primed and to disease outcome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3083.2005.01686.x
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Hazard from volcanic ash (1991)
    [s.l.] : Nature Publishing Group
    Nature 354 (1991), S. 25-25 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR - Volcanic ash clouds pose a significant hazard to aircraft in flight. There were at least 14 such incidents with the volcanic ash clouds arising from the recent eruptions of Mount Pinatubo in the Philippines. Commercial aircraft have no means of discriminating between ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/354025a0
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    Paper (German National Licenses)
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  • 6
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    An innovative technique for TPB deposition on convex window photomultiplier tubes (2018)
    Institute of Physics Publishing (IOP)
    Details
    Publication Date: 2018-12-15
    Description: Tetraphenyl-butadiene (TPB) is an organic fluorescent chemical compound generally used as wavelength shifter thanks to its extremely high efficiency to convert ultra-violet photons into visible light. A common method to use TPB with detectors sensitive to visible light, such as photomultiplier tubes (PMTs), is to deposit thin layers on the device window. To obtain effective TPB layers, different procedures can be used. In this work a specific evaporation technique adopted to coat 8 in convex windows photomultiplier tubes is presented. It consists in evaporating TPB by means of a Knudsen cell , which allows to strictly control the process, and in a rotating sample support, which guarantees the uniformity of the deposition. Simulation results and experimental tests demonstrate the effectiveness of this evaporation technique from the point of view of deposition uniformity and light conversion efficiency.
    Electronic ISSN: 1748-0221
    Topics: Physics
    Published by Institute of Physics Publishing (IOP)
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  • 7
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    Test and characterization of 400 Hamamatsu R5912-MOD photomultiplier tubes for the ICARUS T600 detector (2018)
    Institute of Physics Publishing (IOP)
    Details
    Publication Date: 2018-10-27
    Description: ICARUS T600 will be operated as far detector of the Short Baseline Neutrino program at Fermilab (U.S.A.), which foresees three liquid argon time projection chambers along the Booster Neutrino Beam line to search for a LSND-like sterile neutrino signal. The detector employs 360 photomultiplier tubes, Hamamatsu model R5912-MOD, suitable for cryogenic applications. A total of 400 PMTs were procured from Hamamatsu and tested at room temperature to evaluate the performance of the devices and their compliance to detect the liquid argon scintillation light in the T600 detector. Furthermore 60 units were also characterized at cryogenic temperature, in liquid argon bath, to evaluate any parameter variation which could affect the scintillation light detection. All the tested PMTs were found to comply with the requirements of ICARUS T600 and a subset of 360 specimens was selected for the final installation in the detector.
    Electronic ISSN: 1748-0221
    Topics: Physics
    Published by Institute of Physics Publishing (IOP)
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  • 8
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    Stratospheric volcanic ash emissions from the 13 February 2014 Kelut eruption (2015)
    Wiley-Blackwell
    Details
    Publication Date: 2015-01-09
    Description: Abstarct Mt. Kelut (Indonesia) erupted explosively around 15:50 UT on 13 February 2014 sending ash and gases into the stratosphere. Satellite ash retrievals from MTSAT observations and FLEXPART transport modelling are combined within an inversion framework to estimate the volcanic ash source term and to study ash transport. The estimated source term suggests that most of the ash was injected to altitudes of 16-17 km, in agreement with space-based lidar data. Modelled ash concentrations along the flight track of a commercial aircraft that encountered the ash cloud indicate that it flew under the main ash cloud and encountered maximum ash concentrations of 9±3 mg m -3 , mean concentrations of 2±1 mg m -3 over a period of 10-11 minutes of the flight, giving a dosage of 1.2±0.3 g s m -3 . Satellite data could not be used directly to observe the ash cloud encountered by the aircraft, whereas inverse modelling revealed its presence.
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley-Blackwell on behalf of American Geophysical Union (AGU).
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  • 9
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    SO2 and ash plume retrievals using MSG-SEVIRI measurements. Test case: 24 November 2006 Mt. Etna eruption. (2008)
    Details
    Publication Date: 2017-04-04
    Description: In this work the Thermal InfraRed (TIR) measurements of the Spin Enhanced Visible and Infrared Imager (SEVIRI) on board the Meteosat Second Generation (MSG) geosyncronous satellite, have been used to estimate the daily evolution of the SO2 columnar abundance and ash plume optical thickness, particle effective radius and total mass of Mt. Etna volcanic plume. As test case the 24 November 2006 eruption has been considered. SEVIRI is an optical imaging radiometer characterized by 12 spectral channels, a high temporal resolution (one image every 15 minutes) and a 9 km2 footprint. The instrument’s spectral range includes the 8.7 mm band (channel 7) and the10.8 and 12.0 mm split window bands (channels 9 and 10) used respectively for SO2 retrieval and volcanic ash detection and retrievals. The SO2 columnar abundance is estimated by means of a Look-Up Table (LUT) least squares fit procedure applied to channel 7 while the ash detection and retrievals are carried out by using the Brightness Temperature Difference algorithm applied to channels 9 and 10. All the simulations needed for the retrievals have been realized using the WMO Trapani meteo station atmospheric profiles and MODTRAN 4 radiative transfer model. The SEVIRI volcanic plume SO2 and ash retrieval has been compared with the results obtained by processing the data collected during the same eruption by the MODIS sensor on board of Aqua and Terra satellites. Results show the ability of SEVIRI to recognize and estimate the daily trend of SO2 and ash in an eruptive plume; for the 24 November 2006 eruption, the SO2 and ash emissions start at about 4 am and 9 am respectively and terminate simultaneously at about 3 pm. The comparison between SEVIRI and MODIS retrievals indicates a good agreement.
    Description: Published
    Description: Naples
    Description: 1.10. TTC - Telerilevamento
    Description: open
    Keywords: SO2 retrieval ; ash retrieval ; MSG-SEVIRI ; MODIS ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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  • 10
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    Retrieval of SO2 from thermal infrared satellite measurements: correction procedures for the effects of volcanic ash (2009)
    EGU
    Details
    Publication Date: 2017-04-04
    Description: The simultaneous presence of SO2 and ash in a volcanic plume can lead to a significant error in the SO2 column abundance retrieval when multispectral Thermal InfraRed (TIR) data are used. The ash particles within the plume with effective radii from 1 to 10μm reduce the Top Of Atmosphere (TOA) radiance in the entire TIR spectral range, including the channels used for SO2 retrieval. The net effect is a significant SO2 overestimation. In this work the interference of ash is discussed and two correction procedures for satellite SO2 volcanic plume retrieval in the TIR spectral range are developed to achieve an higher computational speed and a better accuracy. The ash correction can be applied when the sensor spectral range includes the 7.3 and/or 8.7μm SO2 absorption bands, and the split window bands centered around 11 and 12μm required for ash retrieval. This allows the possibility of simultaneous estimation of both volcanic SO2 and ash in the same data set. The proposed ash correction procedures have been applied to the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Spin Enhanced Visible and Infrared Imager (SEVIRI) measurements. Data collected during the 24 November 2006 Mt. Etna eruption have been used to illustrate the technique. The SO2 and ash estimation is carried out by using a best weighted least squares fit method and the Brightness Temperature Difference (BTD) procedures, respectively. The simulated TOA radiance Look-Up Table (LUT) needed for the SO2 column abundance and the ash retrievals have been computed using the MODTRAN 4 Radiative Transfer Model. The results show the importance of the ash correction on SO2 retrievals at 8.7μm, where the corrected SO2 column abundance values are less than 50% of the uncorrected values. The ash correction on SO2 retrieval at 7.3μm is much less important and only significant for low SO2 column abundances. Results also show that the simplified and faster correction procedure underestimates the ash correction compared with the more time consuming but more accurate correction procedure. Such underestimation is greater for instruments having better ground pixel resolution, i.e. greater for MODIS than for SEVIRI.
    Description: Published
    Description: 177–191
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 1.10. TTC - Telerilevamento
    Description: N/A or not JCR
    Description: open
    Keywords: volcanic ash retrieval ; volcanic so2 retrieval ; ash correction ; remote sensing ; MODIS ; SEVIRI ; Etna volcano ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 01. Atmosphere::01.01. Atmosphere::01.01.08. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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