High-speed imaging of Strombolian explosions: The ejection velocity of pyroclasts

Explosive volcanic eruptions are defined as the violent ejection of gas and hot fragments from a vent in the Earth's crust. Knowledge of ejection velocity is crucial for understanding and modeling relevant physical processes of an eruption, and yet direct measurements are still a difficult task with largely variable results. Here we apply pioneering high-speed imaging to measure the ejection velocity of pyroclasts from Strombolian explosive eruptions with an unparalleled temporal resolution. Measured supersonic velocities, up to 405 m/s, are twice higher than previously reported for such eruptions. Individual Strombolian explosions include multiple, sub-second-lasting ejection pulses characterized by an exponential decay of velocity. When fitted with an empirical model from shock-tube experiments literature, this decay allows constraining the length of the pressurized gas pockets responsible for the ejection pulses. These results directly impact eruption modeling and related hazard assessment, as well as the interpretation of geophysical signals from monitoring networks

Temporal evolution of the Evershed flow in sunspots. II. Physical properties and nature of Evershed clouds

Context: Evershed clouds (ECs) represent the most conspicuous variation of the Evershed flow in sunspot penumbrae. Aims: We determine the physical properties of ECs from high spatial and temporal resolution spectropolarimetric measurements. Methods: The Stokes profiles of four visible and three infrared spectral lines are subject to inversions based on simple one-component models as well as more sophisticated realizations of penumbral flux tubes embedded in a static ambient field (uncombed models). Results: According to the one-component inversions, the EC phenomenon can be understood as a perturbation of the magnetic and dynamic configuration of the penumbral filaments along which these structures move. The uncombed inversions, on the other hand, suggest that ECs are the result of enhancements in the visibility of penumbral flux tubes. We conjecture that the enhancements are caused by a perturbation of the thermodynamic properties of the tubes, rather than by changes in the vector magnetic field. The feasibility of this mechanism is investigated performing numerical experiments of thick penumbral tubes in mechanical equilibrium with a background field. Conclusions: While the one-component inversions confirm many of the properties indicated by a simple line parameter analysis (Paper I of this series), we tend to give more credit to the results of the uncombed inversions because they take into account, at least in an approximate manner, the fine structure of the penumbra.Comment: Accepted for publication in A&

Novel Potent Muscarinic Receptor Antagonists: Investigation on the Nature of Lipophilic Substituents in the 5- and/or 6-Positions of the 1,4-Dioxane Nucleus

A series of novel 1,4-dioxane analogues of the muscarinic acetylcholine receptor (mAChR) antagonist 2 was synthesized and studied for their affinity at M1-M5 mAChRs. The 6-cyclohexyl-6-phenyl derivative 3b, with a cis configuration between the CH2N+(CH3)3 chain in the 2-position and the cyclohexyl moiety in the 6-position, showed pKi values for mAChRs higher than those of 2 and a selectivity profile analogous to that of the clinically approved drug oxybutynin. The study of the enantiomers of 3b and the corresponding tertiary amine 33b revealed that the eutomers are (2S,6S)-(-)-3b and (2S,6S)-(-)-33b, respectively. Docking simulations on the M3 mAChR-resolved structure rationalized the experimental observations. The quaternary ammonium function, which should prevent the crossing of the blood-brain barrier, and the high M3/M2 selectivity, which might limit cardiovascular side effects, make 3b a valuable starting point for the design of novel antagonists potentially useful in peripheral diseases in which M3 receptors are involved

Time-series analysis of fissure-fed multi-vent activity: a snapshot from the July 2014 eruption of Etna volcano (Italy)

The April to May 2010 eruption of Eyjafjallajökull (Iceland) volcano was characterized by a large compositional variability of erupted products. To contribute to the understanding of the plumbing system dynamics of this volcano, we present new EMPA and LA-ICP-MS data on groundmass glasses of ash particles and minerals erupted between April 15 and 22. The occurrence of disequilibrium textures in minerals, such as resorption and inverse zoning, indicate that open system processes were involved in determining the observed compositional variability. The variation of major and trace element data of glasses corroborates this hypothesis indicating that mixing between magma batches with different compositions interacted throughout the whole duration of the eruption. In particular, the arrival of new basaltic magma into the plumbing system of the volcano destabilized and remobilized magma batches of trachyandesite and rhyolite compositions that, according to geophysical data, might have intruded as sills over the past 20 years beneath the Eyjafjallajökull edifice. Two mixing processes are envisaged to explain the time variation of the compositions recorded by the erupted tephra. The first occurred between basaltic and trachyandesitic end-members. The second occurred between trachyandesite and rhyolites. Least-squares modeling of major elements supports this hypothesis. Furthermore, investi- gation of compositional histograms of trace elements allows us to estimate the initial proportions of melts that interacted to generate the compositional variability triggered by mixing of trachyandesites and rhyolites.Published515V. Dinamica dei processi eruttivi e post-eruttiviJCR Journa

Evaluation of Textural and Sensory Properties on Typical Spanish Small Cakes Designed Using Alternative Flours

[EN] The objective of this study was to evaluate the effect of wheat flour substitution with toasted corn, quinoa, and sorghum flours on the overall perception and texture of typical Spanish small cakes named madeleine. In order to evaluate these characteristics, a texture profile analysis (TPA) and a sensory analysis were carried out. TPA showed that the replacement of wheat flour by sorghum flour did not affect significantly texture parameters of cakes. Hedonic sensory tests were also conducted revealing that the cake prepared with sorghum flour was highly appreciated by the consumers as it got scores similar to traditional cakes made with wheat flour.Casas Moreno, MDM.; Barreto Palacios, VJ.; González Carrascosa, R.; Iborra Bernad, MDC.; Andrés Bello, MD.; Martínez Monzó, J.; García-Segovia, P. (2015). Evaluation of Textural and Sensory Properties on Typical Spanish Small Cakes Designed Using Alternative Flours. Journal of Culinary Science and Technology. 13(1):19-28. doi:10.1080/15428052.2014.952475S1928131Baldwin, R. R., Baldry, R. P., & Johansen, R. G. (1972). Fat systems for bakery products. Journal of the American Oil Chemists’ Society, 49(8), 473-477. doi:10.1007/bf02582482Beleia, A., Miller, R. A., & Hoseney, R. C. (1996). Starch Gelatinization in Sugar Solutions. Starch - Starke, 48(7-8), 259-262. doi:10.1002/star.19960480705Brannan, G. L., Setser, C. S., Kemp, K. E., Seib, P. A., & Roozeboom, K. (2001). Sensory Characteristics of Grain Sorghum Hybrids with Potential for Use in Human Food. Cereal Chemistry Journal, 78(6), 693-700. doi:10.1094/cchem.2001.78.6.693Cauvain, S. P., & Young, L. S. (Eds.). (2006). Baked Products. doi:10.1002/9780470995907Chieh, C. (s. f.). Water. Bakery Products, 211-232. doi:10.1002/9780470277553.ch11Conforti, F. D. (s. f.). Cake Manufacture. Bakery Products, 393-410. doi:10.1002/9780470277553.ch22Ghotra, B. S., Dyal, S. D., & Narine, S. S. (2002). Lipid shortenings: a review. Food Research International, 35(10), 1015-1048. doi:10.1016/s0963-9969(02)00163-1Kiosseoglou, V., & Paraskevopoulou, A. (s. f.). Eggs. Bakery Products, 161-172. doi:10.1002/9780470277553.ch8Lai, H.-M., & Lin, T.-C. (s. f.). Bakery Products: Science and Technology. Bakery Products, 3-68. doi:10.1002/9780470277553.ch1Lau, M. ., Tang, J., & Paulson, A. . (2000). Texture profile and turbidity of gellan/gelatin mixed gels. Food Research International, 33(8), 665-671. doi:10.1016/s0963-9969(00)00111-3LINDLEY, M. G. (1987). Sucrose in baked products. Nutrition Bulletin, 12(1), 41-45. doi:10.1111/j.1467-3010.1987.tb00011.xMastromatteo, M., Chillo, S., Iannetti, M., Civica, V., & Del Nobile, M. A. (2011). Formulation optimisation of gluten-free functional spaghetti based on quinoa, maize and soy flours. International Journal of Food Science & Technology, 46(6), 1201-1208. doi:10.1111/j.1365-2621.2011.02613.xOreopoulou, V. (s. f.). Fat Replacers. Bakery Products, 193-210. doi:10.1002/9780470277553.ch10Peressini, D., Pin, M., & Sensidoni, A. (2011). Rheology and breadmaking performance of rice-buckwheat batters supplemented with hydrocolloids. Food Hydrocolloids, 25(3), 340-349. doi:10.1016/j.foodhyd.2010.06.012Sanz, T., Salvador, A., Baixauli, R., & Fiszman, S. M. (2009). Evaluation of four types of resistant starch in muffins. II. Effects in texture, colour and consumer response. European Food Research and Technology, 229(2), 197-204. doi:10.1007/s00217-009-1040-1Taylor, J. R. N., Schober, T. J., & Bean, S. R. (2006). Novel food and non-food uses for sorghum and millets. Journal of Cereal Science, 44(3), 252-271. doi:10.1016/j.jcs.2006.06.009Wilderjans, E., Luyts, A., Brijs, K., & Delcour, J. A. (2013). Ingredient functionality in batter type cake making. Trends in Food Science & Technology, 30(1), 6-15. doi:10.1016/j.tifs.2013.01.001Wilderjans, E., Pareyt, B., Goesaert, H., Brijs, K., & Delcour, J. A. (2008). The role of gluten in a pound cake system: A model approach based on gluten–starch blends. Food Chemistry, 110(4), 909-915. doi:10.1016/j.foodchem.2008.02.079Wilson, N. L. W. (2011). How the Cookie Crumbles: A Case Study of Gluten-Free Cookies and Random Utility. American Journal of Agricultural Economics, 94(2), 576-582. doi:10.1093/ajae/aar081Zhu, J.-H., Yang, X.-Q., Ahmad, I., Li, L., Wang, X.-Y., & Liu, C. (2008). Rheological properties of κ-carrageenan and soybean glycinin mixed gels. Food Research International, 41(3), 219-228. doi:10.1016/j.foodres.2007.11.00

Significant changes in the magma dynamics of Stromboli steady-state volcano recorded by clinopyroxene crystals.

&amp;lt;p&amp;gt;Steady-state volcanic activity implies equilibrium between the rate of magma replenishment and eruption of compositionally homogeneous magmas, lasting for tens to thousands of years in an open conduit system. The Present-day activity of Stromboli volcano (Aeolian Islands, Southern Italy) has long been recognised as typical of a steady-state volcano, with a shallow magmatic reservoir (highly porphyritic or hp-magma) continuously refilled by more mafic magma (with low phenocryst content or lp-magma) at a constant rate and accompanied by mixing, crystallisation and eruption. The lp-magma is erupted only during more violent explosive events (paroxysms), which usually occur at intervals of a few years. However, the two most recent paroxysms occurred at very short timescales on 3 July and 28 August 2019 offering the unique opportunity of obtaining crucial information on the current magma dynamics of Stromboli.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Albeit the plumbing system shows such uniformity, clinopyroxene phenocrysts exhibit marked chemical heterogeneities and complex textures caused by continuous lp-hp magma mixing as well as antecryst recycling from different mush portions. The compositional zoning in clinopyroxene provides essential information on pre-eruptive magma dynamics, indicating multi-stage crystallization across the lp-hp-reservoirs, where diopsidic compositions are markers of more primitive, high-T magmas injecting into shallow, low-T domains of the plumbing system. By comparing clinopyroxene texture, chemistry and residence times from the Present-day eruptions with the previous Post-Pizzo activity, we conclude that a distinct phase in the life of Stromboli volcano commenced after the violent 2003 paroxysm. Our observations suggest there are more efficient mechanisms of mush disruption and cannibalization, in which old diopsidic antecrysts are continuously remobilized and transported by the lp-magmas permeating the mush. The disappearance of diopsidic recharge bands within augitic overgrowths indicates that over time, magmatic injections feeding the persistent Present-day activity are more intensively mixed and homogenized prior to eruption.&amp;lt;/p&amp;gt; </jats:p

The Imaging Magnetograph eXperiment (IMaX) for the Sunrise balloon-borne solar observatory

The Imaging Magnetograph eXperiment (IMaX) is a spectropolarimeter built by four institutions in Spain that flew on board the Sunrise balloon-borne telesocope in June 2009 for almost six days over the Arctic Circle. As a polarimeter IMaX uses fast polarization modulation (based on the use of two liquid crystal retarders), real-time image accumulation, and dual beam polarimetry to reach polarization sensitivities of 0.1%. As a spectrograph, the instrument uses a LiNbO3 etalon in double pass and a narrow band pre-filter to achieve a spectral resolution of 85 mAA. IMaX uses the high Zeeman sensitive line of Fe I at 5250.2 AA and observes all four Stokes parameters at various points inside the spectral line. This allows vector magnetograms, Dopplergrams, and intensity frames to be produced that, after reconstruction, reach spatial resolutions in the 0.15-0.18 arcsec range over a 50x50 arcsec FOV. Time cadences vary between ten and 33 seconds, although the shortest one only includes longitudinal polarimetry. The spectral line is sampled in various ways depending on the applied observing mode, from just two points inside the line to 11 of them. All observing modes include one extra wavelength point in the nearby continuum. Gauss equivalent sensitivities are four Gauss for longitudinal fields and 80 Gauss for transverse fields per wavelength sample. The LOS velocities are estimated with statistical errors of the order of 5-40 m/s. The design, calibration and integration phases of the instrument, together with the implemented data reduction scheme are described in some detail.Comment: 17 figure

Magma recharge and mush rejuvenation drive paroxysmal activity at Stromboli volcano

AbstractOpen-conduit basaltic volcanoes can be characterised by sudden large explosive events (paroxysms) that interrupt normal effusive and mild explosive activity. In June-August 2019, one major explosion and two paroxysms occurred at Stromboli volcano (Italy) within only 64 days. Here, via a multifaceted approach using clinopyroxene, we show arrival of mafic recharges up to a few days before the onset of these events and their effects on the eruption pattern at Stromboli, as a prime example of a persistently active, open-conduit basaltic volcano. Our data indicate a rejuvenated Stromboli plumbing system where the extant crystal mush is efficiently permeated by recharge magmas with minimum remobilisation promoting a direct linkage between the deeper and the shallow reservoirs that sustains the currently observed larger variability of eruptive behaviour. Our approach provides vital insights into magma dynamics and their effects on monitoring signals demonstrating the power of petrological studies in interpreting patterns of surficial activity.</jats:p

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13