Correlations between self-esteem and self-efficacy among master of social work students and bachelor of social work students

This purpose of the present study is to examine the correlations between self-esteem and self-efficacy among undergrade and graduate level social work students in order to determine how perceived self-esteem affects student\u27s ability to perform job tasks

Spotlight on deep carbon research.

Professor Marie Edmonds is a volcanologist at the University of Cambridge. She is interested in the role of magmatic volatiles in magma genesis, volcanic eruptions, and volatile geochemical cycling. Dr. Robert Hazen is a geologist at Carnegie Science and executive director of the Deep Carbon Observatory. His latest research has focused on the co-evolution of the geospheres and biospheres, and mineral diversity and distribution. Marie and Robert apply their research to help understand the chemical and biological roles of carbon in Earth

Observing eruptions of gas-rich compressible magmas from space

Observations of volcanoes from space are a critical component of volcano monitoring, but we lack quantitative integrated models to interpret them. The atmospheric sulfur yields of eruptions are variable and not well correlated with eruption magnitude and for many eruptions the volume of erupted material is much greater than the subsurface volume change inferred from ground displacements. Up to now, these observations have been treated independently, but they are fundamentally linked. If magmas are vapour-saturated before eruption, bubbles cause the magma to become more compressible, resulting in muted ground displacements. The bubbles contain the sulfur-bearing vapour injected into the atmosphere during eruptions. Here we present a model that allows the inferred volume change of the reservoir and the sulfur mass loading to be predicted as a function of reservoir depth and the magma’s oxidation state and volatile content, which is consistent with the array of natural data

The control of magma crystallinity on the fluctuations in gas composition at open vent basaltic volcanoes

Basaltic open vent volcanoes are major global sources of volcanic gases. Many of these volcanoes outgas via intermittent Strombolian-type explosions separated by periods of passive degassing. The gas emitted during the explosions has high molar CO2/SO2 and SO2/HCl ratios, while during the passive degassing these ratios are lower. We present new laboratory experiments in a model volcanic conduit, which suggest that these differences in gas geochemistry are a consequence of gas migration through crystal-rich magma. We show that gas may flow along channels through the particle-laden liquid and, at a critical depth, the gas may displace an overlying crystal-rich plug en masse, producing a growing slug of gas. Owing to the friction on the walls of the conduit, this plug becomes progressively sheared and weakened until gas enriched in the least soluble volatiles breaks through, causing an explosion at the surface. When the gas slug bursts, liquid is drawn up in its wake, which exsolves the more soluble volatile components, which then vent passively at the surface until the next explosive slug-bursting event

Microstructural constraints on magmatic mushes under Kīlauea Volcano, Hawai'i.

Distorted olivines of enigmatic origin are ubiquitous in erupted products from a wide range of volcanic systems (e.g., Hawai'i, Iceland, Andes). Investigation of these features at Kīlauea Volcano, Hawai'i, using an integrative crystallographic and chemical approach places quantitative constraints on mush pile thicknesses. Electron backscatter diffraction (EBSD) reveals that the microstructural features of distorted olivines, whose chemical composition is distinct from undistorted olivines, are remarkably similar to olivines within deformed mantle peridotites, but inconsistent with an origin from dendritic growth. This, alongside the spatial distribution of distorted grains and the absence of adcumulate textures, suggests that olivines were deformed within melt-rich mush piles accumulating within the summit reservoir. Quantitative analysis of subgrain geometry reveals that olivines experienced differential stresses of ∼3-12 MPa, consistent with their storage in mush piles with thicknesses of a few hundred metres. Overall, our microstructural analysis of erupted crystals provides novel insights into mush-rich magmatic systems

On the use of plume models to estimate the flux in volcanic gas plumes.

Many of the standard volcanic gas flux measurement approaches involve absorption spectroscopy in combination with wind speed measurements. Here, we present a new method using video images of volcanic plumes to measure the speed of convective structures combined with classical plume theory to estimate volcanic fluxes. We apply the method to a nearly vertical gas plume at Villarrica Volcano, Chile, and a wind-blown gas plume at Mount Etna, Italy. Our estimates of the gas fluxes are consistent in magnitude with previous reported fluxes obtained by spectroscopy and electrochemical sensors for these volcanoes. Compared to conventional gas flux measurement techniques focusing on SO2, our new model also has the potential to be used for sulfur-poor plumes in hydrothermal systems because it estimates the H2O flux

Architecture and dynamics of magma reservoirs.

This introductory article provides a synopsis of our current understanding of the form and dynamics of magma reservoirs in the crust. This knowledge is based on a range of experimental, observational and theoretical approaches, some of which are multidisclipinary and pioneering. We introduce and provide a contextual background for the papers in this issue, which cover a wide range of topics, encompassing magma storage, transport, behaviour and rheology, as well as the timescales on which magma reservoirs operate. We summarize the key findings that emerged from the meeting and the challenges that remain. The study of magma reservoirs has wide implications not only for understanding geothermal and magmatic systems, but also for natural oil and gas reservoirs and for ore deposit formation. This article is part of the Theo Murphy meeting issue 'Magma reservoir architecture and dynamics'

On the use of plume models to estimate the flux in volcanic gas plumes.

Many of the standard volcanic gas flux measurement approaches involve absorption spectroscopy in combination with wind speed measurements. Here, we present a new method using video images of volcanic plumes to measure the speed of convective structures combined with classical plume theory to estimate volcanic fluxes. We apply the method to a nearly vertical gas plume at Villarrica Volcano, Chile, and a wind-blown gas plume at Mount Etna, Italy. Our estimates of the gas fluxes are consistent in magnitude with previous reported fluxes obtained by spectroscopy and electrochemical sensors for these volcanoes. Compared to conventional gas flux measurement techniques focusing on SO2, our new model also has the potential to be used for sulfur-poor plumes in hydrothermal systems because it estimates the H2O flux

Magmas Erupted during the Main Pulse of Siberian Traps Volcanism were Volatile-poor

The eruption of the Siberian Traps Large Igneous Province (SLIP) at the Permo-Triassic boundary was synchronous with environmental degradation and the largest known mass extinction in the geological record. The volatile emissions associated with these eruptions have been linked to the environmental change yet we understand little of their source and magnitude and how they varied with time. There are a number of possible sources for the volatiles that were emitted during the eruptions: the mantle (including metasomatized lithosphere), volatile-rich sediments (through metamorphism or direct assimilation) and the crustal basement. To assess the relative importance of these sources (with the exception of the metamorphic outgassing source), we have conducted a geochemical study of melt inclusions hosted by clinopyroxene in Siberian Traps low-Ti tholeiitic lavas and sills of the Khakanchansky, Ayansky and Khonnamakitsky Formations. The magmas were not emplaced into or erupted onto evaporite deposits, in contrast to samples studied previously. The trace element compositions of the melt inclusions are highly variable compared with the uniform whole-rocks, exhibiting a wide range of La/Yb ratios from 0·7 to 9·5. The melt geochemistry is consistent with relatively large degrees of partial melting of a dominantly peridotite mantle source. A negative Nb anomaly indicates a degree of crustal contamination, but there is no evidence for contamination by volatile-rich evaporites. Enrichment of some of the melts in large ion lithophile elements (Ba, Sr) indicates their interaction with a fluid. We suggest that, consistent with the observed depletion in other incompatible trace elements in the melt inclusions, the volatile concentrations in the melts were relatively low, and that subsequently the melts underwent variable degrees of degassing in the crust. Overall, the melts are more volatile-poor than those reported previously from the SLIP and were erupted after the first “pulse” of more volatile-rich magmas described by Sobolev et al. (2015). These volatile-poor magmas may have been widespread across the region during the Siberian Traps eruptions once a pyroxenite component in the mantle source had been exhausted

Extensive, water-rich magma reservoir beneath southern Montserrat

South Soufriere Hills and Soufriere Hills volcanoes are two km apart at the southern end of the island of Montserrat, West Indies. Their magmas are distinct geochemically, despite these volcanoes having been active contemporaneously at 131-129 ka. We use the water content of pyroxenes and melt inclusion data to reconstruct the bulk water contents of magmas and their depth of storage prior to eruption. Pyroxenes contain up to 281 ppm H2O, with significant variability between crystals and from core to rim in individual crystals. The Al content of the enstatites from Soufriere Hills Volcano (SHV) is used to constrain melt-pyroxene partitioning for H2O. The SHV enstatite cores record melt water contents of 6-9 wt%. Pyroxene and melt inclusion water concentration pairs from South Soufriere Hills basalts independently constrain pyroxene-melt partitioning of water and produces a comparable range in melt water concentrations. Melt inclusions recorded in plagioclase and in pyroxene contain up to 6.3 wt% H2O. When combined with realistic melt CO2 contents, the depth of magma storage for both volcanoes ranges from 5 to 16 km. The data are consistent with a vertically protracted crystal mush in the upper crust beneath the southern part of Montserrat which contains heterogeneous bodies of eruptible magma. The high water contents of the magmas suggest that they contain a high proportion of exsolved fluids, which has implications for the rheology of the mush and timescales for mush reorganisation prior to eruption. A depletion in water in the outer 50-100 microns of a subset of pyroxenes from pumices from a Vulcanian explosion at Soufriere Hills in 2003 is consistent with diffusive loss of hydrogen during magma ascent over 5-13 hours. These timescales are similar to the mean time periods between explosions in 1997 and in 2003, raising the possibility that the driving force for this repetitive explosive behaviour lies not in the shallow system, but in the deeper parts of a vertically protracted crustal magma storage system.ME acknowledges NERC grant NE/I016694/1 and NERC ion probe facility grant IMF429/0511 and Cees-Jan de Hoog, who provided invaluable assistance with SIMS measurements and calibration. MC acknowledges an Alexander Von Humboldt fellowship.This is the author accepted manuscript. The final version is available from Elsevier via https://doi.org/10.1016/j.lithos.2016.02.02