191 research outputs found

    SUSTAIN drilling at Surtsey volcano, Iceland, tracks hydrothermal and microbiological interactions in basalt 50 years after eruption

    Get PDF
    The 2017 Surtsey Underwater volcanic System for Thermophiles, Alteration processes and INnovative concretes (SUSTAIN) drilling project at Surtsey volcano, sponsored in part by the International Continental Scientific Drilling Program (ICDP), provides precise observations of the hydrothermal, geochemical, geomagnetic, and microbiological changes that have occurred in basaltic tephra and minor intrusions since explosive and effusive eruptions produced the oceanic island in 1963–1967. Two vertically cored boreholes, to 152 and 192 m below the surface, were drilled using filtered, UV-sterilized seawater circulating fluid to minimize microbial contamination. These cores parallel a 181 m core drilled in 1979. Introductory investigations indicate changes in material properties and whole-rock compositions over the past 38 years. A Surtsey subsurface observatory installed to 181 m in one vertical borehole holds incubation experiments that monitor in situ mineralogical and microbial alteration processes at 25–124 ∘C. A third cored borehole, inclined 55∘ in a 264∘ azimuthal direction to 354 m measured depth, provides further insights into eruption processes, including the presence of a diatreme that extends at least 100 m into the seafloor beneath the Surtur crater. The SUSTAIN project provides the first time-lapse drilling record into a very young oceanic basaltic volcano over a range of temperatures, 25–141 ∘C from 1979 to 2017, and subaerial and submarine hydrothermal fluid compositions. Rigorous procedures undertaken during the drilling operation protected the sensitive environment of the Surtsey Natural Preserve

    Influence of country and city images on students’ perception of host universities and their satisfaction with the assigned destination for their exchange programmes

    Get PDF
    ABSTRACT: This research focuses on the effect that country image, city image and university image has on students’ a priori satisfaction with the assigned destination for their international exchange programme (Bachelor and Master). In particular, this study establishes six hypotheses related to the causal relationships among the different typologies of image and their effects on students’ satisfaction with the assigned destination to study at least one semester in a host university. In order to contrast these hypotheses, a quantitative research was carried out in the Spanish city of Santander (Spain), by obtaining a sample of 245 international students who participated in an exchange programme at the University of Cantabria. The research findings are: (1) students’ satisfaction with the assigned destination is positively influenced by the university image; (2) the university image is positively influenced by the city image; and (3) the city image is positively influenced by the country image

    An organizational impression management perspective on the formation of corporate reputations

    Get PDF
    Researchers have only recently turned their attention to the study of corporate reputation. As is characteristic of many early areas of management inquiry, the field is decidedly multidisciplinary and disconnected. This article selectively reviews reputation research conducted mainly during the past decade. A framework is proposed that views reputation from the perspective of organizational impression management. Corporations are viewed as social actors, intent on enhancing their respectability and impressiveness in the eyes of constituents

    Timing and pace of dairying inception and animal husbandry practices across Holocene North Africa

    Get PDF
    The timing and extent of the adoption and exploitation of domesticates and their secondary products, across Holocene North Africa, has long been the subject of debate. The three distinct areas within the region, Mediterranean north Africa, the Nile Valley and the Sahara, each with extremely diverse environments and ecologies, demonstrate differing trajectories to pastoralism. Here, we address this question using a combination of faunal evidence and organic residue analyses of c. 300 archaeological vessels from sites in Algeria, Libya and Sudan. This synthesis of new and published data provides a broad regional and chronological perspective on the scale and intensity of domestic animal exploitation and the inception of dairying practices in Holocene North Africa. Following the introduction of domesticated animals into the region our results confirm a hiatus of around one thousand years before the adoption of a full pastoral economy, which appears first in the Libyan Sahara, at c. 5200 BCE, subsequently appearing at c. 4600 BCE in the Nile Valley and at 4400–3900 BCE in Mediterranean north Africa

    Lakeside View: Sociocultural Responses to Changing Water Levels of Lake Turkana, Kenya

    Get PDF

    A case analysis of energy savings performance contract projects and photovoltaic energy at Fort Bliss, El Paso, Texas

    Get PDF
    MBA Professional ReportThe purpose of this MBA Project is to review existing policy of the Federal Energy Management Program under the purview of National Renewal Energy Laboratory (NREL) for Energy Savings Performance Contracts (ESPCs). This project will assess the ability for the Department of Defense to incorporate emerging technologies in alternative energy to supplement or replace existing power sources for DoD installations within the current Energy Savings Performance Contract policy. To do this the project will review previous and existing Energy Savings Performance Contracts. Further, this project will conduct a cost-benefit analysis of conventional power versus emerging photovoltaic energy for the Army’s Fort Bliss in El Paso, TX. The project will also analyze energy demands based on a new force alignment at Fort Bliss in accordance with the recent Base Realignment and Closure (BRAC) findings. The project will review current Energy Performance Contract Policy and recommend changes to allow for the use of emerging alternative energy technologies.http://archive.org/details/acasenalysisofen109459676Lieutenant, United States Navy, Lieutenant Commander, United States Navy, Lieutenant Commander, United States NavyApproved for public release; distribution is unlimited

    Investigation of the structural conformation of biphenyl by solid state 13C NMR and quantum chemical NMR shift calculations

    No full text
    abstractThe principal values of the 13C chemical-shift tensor (CST) for biphenyl have been determined with the FIREMAT experiment. The internal dihedral angle between the benzene rings in biphenyl is estimated to fall between 10 and 20° on the basis of quantum mechanical calculations of the CST principal values. A composite model of motion in the system, with contributions both from internal jumping between enantiomeric structures and from overall molecular librations, yields the smallest variance between predicted and measured values for an internal twist angle of 15° between the rings and a mean libration angle of ±12° from the most favored molecular orientation. The composite model is clearly preferred to a motionless model (with >98% probability) and is also preferred over either of the isolated contributing dynamics, i.e., only libration or only internal jumping
    corecore