3,950 research outputs found

    Glass in the submarine section of the HSDP2 drill core, Hilo, Hawaii

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    The Hawaii Scientific Drilling Project recovered ~3 km of basalt by coring into the flank of Mauna Kea volcano at Hilo, Hawaii. Rocks recovered from deeper than ~1 km were deposited below sea level and contain considerable fresh glass. We report electron microprobe analyses of 531 glasses from the submarine section of the core, providing a high-resolution record of petrogenesis over ca. 200 Kyr of shield building of a Hawaiian volcano. Nearly all the submarine glasses are tholeiitic. SiO2 contents span a significant range but are bimodally distributed, leading to the identification of low-SiO2 and high-SiO2 magma series that encompass most samples. The two groups are also generally distinguishable using other major and minor elements and certain isotopic and incompatible trace element ratios. On the basis of distributions of high- and low-SiO2 glasses, the submarine section of the core is divided into four zones. In zone 1 (1079–~1950 mbsl), most samples are degassed high-SiO2 hyaloclastites and massive lavas, but there are narrow intervals of low-SiO2 hyaloclastites. Zone 2 (~1950–2233 mbsl), a zone of degassed pillows and hyaloclastites, displays a continuous decrease in silica content from bottom to top. In zone 3 (2233–2481 mbsl), nearly all samples are undegassed low-SiO2 pillows. In zone 4 (2481–3098 mbsl), samples are mostly high-SiO2 undegassed pillows and degassed hyaloclastites. This zone also contains most of the intrusive units in the core, all of which are undegassed and most of which are low-SiO2. Phase equilibrium data suggest that parental magmas of the low-SiO2 suite could be produced by partial melting of fertile peridotite at 30–40 kbar. Although the high-SiO2 parents could have equilibrated with harzburgite at 15–20 kbar, they could have been produced neither simply by higher degrees of melting of the sources of the low-SiO2 parents nor by mixing of known dacitic melts of pyroxenite/eclogite with the low-SiO2 parents. Our hypothesis for the relationship between these magma types is that as the low-SiO2 magmas ascended from their sources, they interacted chemically and thermally with overlying peridotites, resulting in dissolution of orthopyroxene and clinopyroxene and precipitation of olivine, thereby generating high-SiO2 magmas. There are glasses with CaO, Al2O3, and SiO2 contents slightly elevated relative to most low-SiO2 samples; we suggest that these differences reflect involvement of pyroxene-rich lithologies in the petrogenesis of the CaO-Al2O3-enriched glasses. There is also a small group of low-SiO2 glasses distinguished by elevated K2O and CaO contents; the sources of these samples may have been enriched in slab-derived fluid/melts. Low-SiO2 glasses from the top of zone 3 (2233–2280 mbsl) are more alkaline, more fractionated, and incompatible-element-enriched relative to other glasses from zone 3. This excursion at the top of zone 3, which is abruptly overlain by more silica-rich tholeiitic magmas, is reminiscent of the end of Mauna Kea shield building higher in the core

    Representations of sources and data: working with exceptions to hierarchy in historical documents

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    No abstract available

    Scavenging Poultry for Poverty Alleviation: A review of experiences with a focus on Bangladesh

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    Report prepared for International Livestock Research Institute.Food Security and Poverty, Livestock Production/Industries,

    Smart technologies for personalized experiences: a case study in the hospitality domain

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    Recent advances in the field of technology have led to the emergence of innovative technological smart solutions providing unprecedented opportunities for application in the tourism and hospitality industry.With intensified competition in the tourism market place, it has become paramount for businesses to explore the potential of technologies, not only to optimize existing processes but facilitate the creation of more meaningful and personalized services and experiences. This study aims to bridge the current knowledge gap between smart technologies and experience personalization to understand how smart mobile technologies can facilitate personalized experiences in the context of the hospitality industry. By adopting a qualitative case study approach, this paper makes a two-fold contribution; it a) identifies the requirements of smart technologies for experience creation, including information aggregation, ubiquitous mobile connectedness and real time synchronization and b) highlights how smart technology integration can lead to two distinct levels of personalized tourism experiences. The paper concludes with the development of a model depicting the dynamic process of experience personalization and a discussion of the strategic implications for tourism and hospitality management and research

    Dynamics of Magma Mixing in Partially Crystallized Magma Chambers: Textural and Petrological Constraints from the Basal Complex of the Austurhorn Intrusion (SE Iceland)

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    The Tertiary Austurhorn intrusive complex in SE Iceland represents an exhumed magma chamber that has recorded an extensive history of magma mixing and mingling. The basal part of the intrusion consists predominantly of granophyres that have been intensively and repeatedly intruded by more mafic magma. This association of granophyres, basic and hybrid rocks at Austurhorn is referred to in the literature as a ‘net-veined' complex, but field relations suggest a much more complex emplacement history. Here we present petrological and physical constraints on the various processes that resulted in magma mixing and mingling and the formation of different generations of hybrid rocks at Austurhorn. The complexity of the mixing and mingling processes increases towards the inferred centre of the intrusion, where chaotic hybrid rocks dominate the exposed lithology. Complex cross-cutting relations between different hybrid generations strongly suggest multiple magma injection and reheating events in the basal part of the shallow magma chamber. Model calculations employing distribution coefficients based on rare earth element concentrations reveal that early stage hybrid magma generations formed by pure endmember mixing between felsic and mafic magma with about 10% mafic fraction in the hybrids. With repeated injections of mafic magma into the base of the magma chamber, the intruding magma interacted to a greater extent with pre-existing hybrids. This led to the formation of hybrid magma compositions that are shifted towards the mafic endmember over time, with up to 30% of the mafic fraction in the hybrids. These mixing processes are recorded in the zonation patterns of clinopyroxene and plagioclase phenocrysts; the latter have been divided into four main groups by cross-correlation analysis. Melt viscosity calculations were performed to constrain the possible conditions of magma mixing and the results indicate that the interaction of the contrasting magmas most probably occurred at temperatures of approximately 1000°C up to 1120°C. This suggests that the initiation of effective magma mixing requires local superheating of the felsic magmas, thereby confining the process to areas of localized, substantial mafic magma injectio

    The influence of consumption vocabulary on the encoding and retrieval of haptic information

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    A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and EconomicsSensory stimuli are often ambiguous, which makes it difficult for consumers to encode and retrieve them, and to construct their preferences. This project studies whether, in a prepurchase context, consumption vocabulary can help consumers to perceive what products are superior on haptic attributes. In an experiment with bed pillows, participants provided with evaluative criteria preferred the pillow with superior haptic attributes more often and to a larger extent than participants who had no evaluative criteria, which suggests the provision of criteria has a positive influence on preference construction. Improvements in memory for haptic attributes and disconnection from incongruent market information derived from that provision were not confirmed

    Hospital Acquired Pressure Injury Gap Analysis

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    Hospital acquired pressure injuries (HAPIs) were identified as an area for a quality improvement (QI) project in a progressive care unit (PCU) in a Midwestern Hospital. In order to reduce HAPIs and provide the best possible preventative care, a gap analysis between the current care practices on the progressive care unit and the best evidence-based practice recommendations for HAPI prevention in the areas of risk/skin assessment, surface support, nutrition and hydration, repositioning/movement, moisture management, and prophylactic dressings was conducted. The Model for Improvement (MFI) was the QI framework that guided this pressure injury gap analysis. The goals of this gap analysis were to identify, collect, and compile information in the areas of risk/skin assessment, support surfaces, nutrition and hydration, repositioning/mobilization, moisture management, friction/shear, and prophylactic dressings. The aim of this QI project was to reduce the incidence of HAPIs in the PCU microsystem and identify the best possible evidence-based HAPI preventative care by examining existing practices and processes that are currently implemented and compare them to the most current CPG recommendations. The evaluation of this information/data will identify opportunities for future QI projects to improve outcomes for HAPI prevention within this microsystem
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