Sulfide saturation and resorption modulates sulfur and metal availability during the 2014–15 Holuhraun eruption, Iceland

Mafic magmas may experience multiple stages of sulfide saturation and resorption during ascent and differentiation. Quenched tephra erupted during the 2014–15 Holuhraun eruption preserve abundant evidence for sulfide resorption, offering a rare opportunity to explore the sulfide life cycle from nucleation to resorption. Specifically, we combine detailed textural and chemical analyses of sulfides and silicate melts with geochemical models of sulfide saturation and degassing. This integrative approach demonstrates that sulfides began nucleating in melts with ~8 wt% MgO, persisted during fractionation to 6.5 wt% MgO, before resorbing heterogeneously in response to sulfur degassing. Sulfides are preserved preferentially in confined geometries within and between crystals, suggesting that kinetic effects impeded sulfur loss from the melt and maintained local sulfide saturation on eruption. The proportion of sulfides exhibiting breakdown textures increases throughout the eruption, coincident with decreasing magma discharge, indicating that sulfide resorption and degassing are kinetically limited. Sulfides likely modulate the emission of sulfur and chalcophile elements to the atmosphere and surface environment, with implications for assessing the environmental impacts and societal hazards of basaltic fissure eruptions

Space Weathering on Near-Earth Objects investigated by neutral-particle detection

The ion-sputtering (IS) process is active in many planetary environments in the Solar System where plasma precipitates directly on the surface (for instance, Mercury, Moon, Europa). In particular, solar-wind sputtering is one of the most important agents for the surface erosion of a Near-Earth Object (NEO), acting together with other surface release processes, such as Photon Stimulated Desorption (PSD), Thermal Desorption (TD) and Micrometeoroid Impact Vaporization (MIV). The energy distribution of the IS-released neutrals peaks at a few eVs and extends up to hundreds of eVs. Since all other release processes produce particles of lower energies, the presence of neutral atoms in the energy range above 10 eV and below a few keVs (Sputtered High-Energy Atoms - SHEA) identifies the IS process. SHEA easily escape from the NEO, due to NEO's extremely weak gravity. Detection and analysis of SHEA will give important information on surface-loss processes as well as on surface elemental composition. The investigation of the active release processes, as a function of the external conditions and the NEO surface properties, is crucial for obtaining a clear view of the body's present loss rate as well as for getting clues on its evolution, which depends significantly on space weather. In this work, an attempt to analyze the processes that take place on the surface of these small airless bodies, as a result of their exposure to the space environment, has been realized. For this reason a new space weathering model (Space Weathering on NEO - SPAWN), is presented. Moreover, an instrument concept of a neutral-particle analyzer specifically designed for the measurement of neutral density and the detection of SHEA from a NEO is proposedComment: 36 page

Abundances of the elements in the solar system

A review of the abundances and condensation temperatures of the elements and their nuclides in the solar nebula and in chondritic meteorites. Abundances of the elements in some neighboring stars are also discussed.Comment: 42 pages, 11 tables, 8 figures, chapter, In Landolt- B\"ornstein, New Series, Vol. VI/4B, Chap. 4.4, J.E. Tr\"umper (ed.), Berlin, Heidelberg, New York: Springer-Verlag, p. 560-63

Recent advances in neutrinoless double beta decay search

Even after the discovery of neutrino flavour oscillations, based on data from atmospheric, solar, reactor, and accelerator experiments, many characteristics of the neutrino remain unknown. Only the neutrino square-mass differences and the mixing angle values have been estimated, while the value of each mass eigenstate still hasn't. Its nature (massive Majorana or Dirac particle) is still escaping. Neutrinoless double beta decay ($0\nu$-DBD) experimental discovery could be the ultimate answer to some delicate questions of elementary particle and nuclear physics. The Majorana description of neutrinos allows the $0\nu$-DBD process, and consequently either a mass value could be measured or the existence of physics beyond the standard should be confirmed without any doubt. As expected, the $0\nu$-DBD measurement is a very difficult field of application for experimentalists. In this paper, after a short summary of the latest results in neutrino physics, the experimental status, the R&D projects, and perspectives in $0\nu$-DBD sector are reviewed.Comment: 36 pages, 7 figures, To be publish in Czech Journal of Physic

Atomic Weights of the Elements 2007 (IUPAC Technical Report)

The latest evaluation of atomic weight determinations and other cognate data has warranted five changes for the standard atomic weights of the elements, Ar(E), from those published previously in the Table of Atomic Weights 2005. The revised standard atomic weight of nickel, Ar(Ni), is 58.6934(4); zinc, Ar(Zn), is 65.38(2); molybdenum, Ar(Mo), is 95.96(2); ytterbium, Ar(Yb), is 173.054(5); and lutetium, Ar(Lu), is 174.9668(1). Standard atomic weight tables abridged to four and five significant figures were also evaluated. The Commission-recommended value for the isotope-amount ratio of n(40Ar)/n(36Ar), which is of importance in geochronology and geochemistry, has been changed to 298.56(31) from 296.03(53) based on new measurements. Atmospheric O2 is recognized as an international measurement standard, along with Vienna Standard Mean Ocean Water (VSMOW) and Vienna Pee Dee Belemnite (VPDB) carbonate for measurement and reporting of differences in relative oxygen isotope-amount ratios delta(17O) and delta(18O).JRC.D.4-Isotope measurement

Ecologia populacional dos Amphipoda (Crustacea) dos fitais de Caiobá, Matinhos, Paraná, Brasil Population ecolocy of Amphipoda (Crustacea) from the phytals of Caiobá, Matinhos, Paraná, Brazil

<abstract language="eng">Spalial and temporal density distributions of Amphipoda from the phytals of Caiobá are described. Air temperature oscillated from 16ºC (August and May) to 23ºC (March), surface water temperature from 17ºC (August) to 25ºC (March) and the salinity from 29.3‰ (May) to 32.8‰ (August). Two samples of 25cm² (for algae less than 5cm long), 100 cm² (for algae between 5-10cm long) and whole plants (for algae more than 10cm long) were removed with a spatula from the rocky surface at Caiobá Beach, in August/86, November/86, March/87 and May/87. After sorting, the algal substrata were weighted, their adsorption coefficient calculated and the sediment retained among the thallii weighted. The average distance between the branching was measured for all branched algae. The densities were calculated in relation to the weight of the algal substrate in grams. Eight phytals were considered: Ulva fasciata Delile, Padina gymnospora (Kútzing) Vickers, Sargassum cymosum Garth, Porphyra atropurpurea (Olivi) De Toni, Gelidium sp., Gymnogongrus griffithsiae (Turner) Martius, Pterocladia capillacea (Gmelin) Bornet &Thurel and Pterosiphonia pennata (Roth) Falkenberg, over which nine Amphipoda species live: Ampithoe ramondi Audouin, 1816, Cymadusa filosa Savigny, 1852, Elasmopus pectenicrus Bate, 1857, Hyale media Dana, 1857, Hyale sp.l, Jassa falcata Montagu, 1895 and Sunampithoe pelagica H. Milne-Edwards, 1830 (Gammaridea). Caprella danilevskii Czerniavski, 1861 and Caprella penantis Leach, 1814 (Caprellidea). Amphipoda densities ranged from 0.27 ind.g-1 to 45.68. ind.g-1. The broad-thallii algae Porphyra, Ulva and Padina harbored lower densities of Amphipoda, whereas those finely branched Pterocladia, Pterosiphonia and Gymnogongrus, the highest values and the less branched Sargassum and Gelidium, intermediate values. The high densities found in the finely branched algae had as main contribution the juvenile recruiting of most Amphipoda. The tide level might have influenced the temporal distribution of the Amphipoda density, due to the distinct time of air exposition in eaeh collection data. Most Amphipoda did not show specific algal substratum colonization: only Sunampithoe pelagica occurred solely in Sargassum. Four species occurred in different branched algae: J. falcata. S. pelagica. C. danilevskii and C. penantis. H. media had Sargassum, Pterocladia, Pterosiphonia and Gymnogongrus as the best algal substrata, whereas Caprellidea, the Pterocladia and Pterosiphonia phytals. High sediment weight in Padina was the main reason for high densities of Hyale sp.l in this phytal. The occurrence of males, females (including ovigerous ones) and juveniles of most Amphipoda species found in the present study indicates a complete life cycle whithin these phytals and corroborates with the assumption of the complexity of this marine coastal ecosystem