6,415 research outputs found

    Corrigendum. Maars to calderas: end-members on a spectrum of explosive volcanic depressions

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    A corrigendum on Maars to calderas: end-members on a spectrum of explosive volcanic depressions by Palladino, D. M., Valentine, G. A., Sottili, G., and Taddeucci, J. (2015). Front. Earth Sci. 3:36. doi: 10.3389/feart.2015.00036 Reason for Corrigendum: In the original article (Palladino et al., 2015), there was an error in Figure 1. The vertical axis of the qualitative plot reported erroneously “ratio of juvenile to lithic materials in deposits outside of depression”. The correct wording is as follows: “ratio of juvenile to total (i.e., juvenile+lithic) materials in deposits outside of depression”. In fact, as it was reported correctly in the text, the amount of juvenilematerial (i.e., scoria or pumice) deposited ouside the different types of explosive volcanic depressions increases from zero (i.e., no juvenile, all lithic products), as is the case of hydrothermal (phreatic) explosion craters, to become largely dominant over the lithic component in the case of ash flow deposits associated with large overpressure collapse calderas. The corrected Figure 1 appears below. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way

    The Roasting of Barley and Malt

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    History of the Potato

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    In this circular, created by the Agricultural Extension Service at South Dakota State College, it addresses the history of the potato through the guidance of the Agronomy department during the year of 192

    The Importance and Uses of the Potato

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    In this circular, created by the Agricultural Extension Service at South Dakota State College, it addresses the importance and uses of the potato through the guidance of the Agronomy department during the year of 1922

    Maars to calderas. End-members on a spectrum of explosive volcanic depressions

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    We discuss maar-diatremes and calderas as end-members on a spectrum of negative volcanic landforms (depressions) produced by explosive eruptions (note—we focus on calderas formed during explosive eruptions, recognizing that some caldera types are not related to such activity). The former are dominated by ejection of material during numerous discrete phreatomagmatic explosions, brecciation, and subsidence of diatreme fill, while the latter are dominated by subsidence over a partly evacuated magma chamber during sustained, magmatic volatile-driven discharge. Many examples share characteristics of both, including landforms that are identified as maars but preserve deposits from non-phreatomagmatic explosive activity, and ambiguous structures that appear to be coalesced maars but that also produced sustained explosive eruptions with likely magma reservoir subsidence. A convergence of research directions on issues related to magma-water interaction and shallow reservoir mechanics is an important avenue toward developing a unified picture of the maar-diatreme-caldera spectrum

    Accreditation And Assessment: A Provocative Approach

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    Gaining and maintaining accreditation is of great importance to colleges and schools (Yunker 2000). In this process, assessment is used to gauge the goals and objectives or the college and school. At no expense, we show that 5 items that remedy the problems associated with assessment. In addition, we give the questions asked during a learning outcomes discussion. Any Dean or administrator who facilitates an active dialogue with faculty increases their chances for a successful accreditation process

    Microstructure and mechanical properties of bulk yttria-partially-stabilized zirconia

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    A commercially available bulk 4.5 mole percent yttria-(Y2O3) partially stabilized zirconia (PSZ) was studied by light microscopy, X-ray analysis, microhardness measurement, and fracture toughness testing. The growth of the precipitates and the phase transformations were studied as a function of aging in air at 1500 C. Aging curves were constructed for both the as received and the solution annealed and quenched materials; the curves showed hardness peaks at 1397 and 1517 Kg/sq mm respectively. The rectangular plate shaped tetragonal precipitates were found to have a 110 habit plane. A total of twelve different types of tetragonal precipitates were found. Grinding of the Y2O3 PSZ into powder did not cause a significant amount of metastable tetragonal precipitates to transform into the monoclinc phase, thus indicating that transformation toughening is not a significant mechanism for the material

    'If I cannot access services then there is no reason for me to test': the impact of health service charges on HIV testing and treatment amongst migrants in England

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    Policy governing entitlement to access government health care for foreign nationals in England is a subject of debate, controversy and confusion. Of particular concern to health providers has been the impact of National Health Service charges on delaying HIV testing and anti-retroviral treatment uptake and adherence amongst certain migrant groups. Data obtained through focus groups with 70 migrants from southern Africa, suggest that confusion over health care entitlements exists amongst those seeking health care and is reported amongst health service providers. This confusion, as well as financial difficulties and fears over deportation facing some migrants, can in turn be a factor influencing their decisions to avoid formal health services, resort to alternative and often ineffective or potentially adverse forms of therapy, and delay HIV testing and treatment uptake

    Deployable antenna phase A study

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    Applications for large deployable antennas were re-examined, flight demonstration objectives were defined, the flight article (antenna) was preliminarily designed, and the flight program and ground development program, including the support equipment, were defined for a proposed space transportation system flight experiment to demonstrate a large (50 to 200 meter) deployable antenna system. Tasks described include: (1) performance requirements analysis; (2) system design and definition; (3) orbital operations analysis; and (4) programmatic analysis

    Photoexcitation dynamics in polyacetylene probed by transient photoinduced resonant Raman scattering

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    Journal ArticleWe have measured photoexcitation dynamics in the picosecond time domain in fully trans and partially isomerized (CH)X and (CD)X films with different cis/trans content ratios, using the technique of transient photoinduced resonant Raman scattering. Following the distinctively different decay kinetics of cis and trans resonantly enhanced vibrations, we observed an intersystem crossing of photoexcitations from cis to trans segments which is dominated by a diffusion process in the cis segments, with a time constant between 24 and 215 ps depending on the cis/trans ratio
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