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Guochun Zhao - One of the best experts on this subject based on the ideXlab platform.
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the applicability of garnet orthopyroxene geobarometry in mantle xenoliths
Lithos, 2011Co-Authors: Guochun ZhaoAbstract:Abstract The various existing garnet–orthopyroxene geoBarometers calibrated based on the Al 2 O 3 or Cr 2 O 3 components in orthopyroxene buffered by coexisting garnet for mantle xenoliths, abbreviated as Al 2 O 3 -barometer and Cr 2 O 3 -barometer, respectively, have been extensively studied, to test their precision by applying them to phase equilibrium experimental data, and to evaluate their validity by applying them to natural pyrolites. The Cr 2 O 3 -Barometers failed in reconstructing the experimental pressures due to imprecise description of activities of garnet and orthopyroxene end members. Several of the Al 2 O 3 -Barometers showed perfect ability in reproducing the experimental pressures and successfully discerned the garnet-facies and garnet–spinel transition facies lherzolites as well as the graphite- or diamond-bearing mantle xenoliths. It is recommended that pressure and temperature estimation of mantle xenoliths may be best determined simultaneously by combining the garnet–orthopyroxene barometer and the two-pyroxene thermometer of Taylor (1998). Orthopyroxenes containing Al 2 O 3 contents of less than 0.37 wt.% should not be used in the pressure estimation in order to avoid significant P–T errors propagated from analytical errors.
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recalibration of the garnet muscovite gm geothermometer and the garnet muscovite plagioclase quartz gmpq geobarometer for metapelitic assemblages
Journal of Petrology, 2006Co-Authors: Guochun ZhaoAbstract:The garnet–muscovite (GM) geothermometer and the garnet– muscovite–plagioclase–quartz (GMPQ) geobarometer have been simultaneously calibrated under conditions of T 1⁄4 450–760 C and P 1⁄4 0.8–11.1 kbar, using a large number of metapelitic samples in the compositional ranges X grt Fe 1⁄4 0.53–0.81, X grt Mg 1⁄4 0.05–0.24, X grt Ca 1⁄4 0.03–0.23 in garnet, X pl Ca 1⁄4 0.17–0.74 in plagioclase, and Fe 1⁄4 0.04–0.16, Mg 1⁄4 0.04–0.13, Al 1⁄4 1.74–1.96 in muscovite on the basis of 11 oxygens. The resulting GM thermometer yielded similar temperature estimates (mostly within ±50 C) to that of the garnet–biotite thermometer, and successfully discerned the expected systematic temperature change of prograde sequences, thermal contact zones and an inverted metamorphic zone. The resulting GMPQ barometer yielded similar pressure estimates (mostly within ±1.0 kbar) to the garnet– aluminum silicate–plagioclase–quartz (GASP) barometer and placed the aluminosilicate-bearing samples in the appropriate aluminosilicate stability fields. Application of the GMPQ barometer to thermal contact aureoles or rocks within limited geographical areas confirmed the expected constant pressures that should exist in these settings. The random errors of the GM thermometer and the GMPQ barometer are estimated to be ±16 C and ±1.5 kbar, respectively. When biotite or aluminosilicate is absent in metapelites, metamorphic P–T conditions may be determined by simultaneously applying the GM thermometer and the GMPQ barometer.
Janegbert Sturm - One of the best experts on this subject based on the ideXlab platform.
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the kof economic barometer version 2014 a composite leading indicator for the swiss business cycle
2014Co-Authors: Klaus Abberger, Michael Graff, Boriss Siliverstovs, Janegbert SturmAbstract:This paper presents a composite leading indicator for the Swiss business cycle corresponding to the growth rate cycle concept. It is the result of a complete overhaul of the KOF Economic Barometer that has been published by the KOF Swiss Economic Institute on a monthly basis since 1976. In line with this tradition, the calculation of the new KOF Barometer comprises two main stages. The first consists of the variable selection procedure; and in the second stage these variables are subsequently transformed into one leading indicator. Whereas in the previous versions of the KOF Barometer six to 25 variables survived the first stage, the new – less discretionary and more automated – version of the first stage is much more generous. Currently, out of a set of 476 variables resulting in 4356 transformations thereof that are tested in the first stage, 219 variables manage to enter the second stage. The increased number of variables underlying the second stage allows a relatively stable and robust KOF Barometer – compared to its previous versions – that has hence no longer to rely on filtering techniques to reduce the noise in the final indicator. In a (pseudo-) real-time analysis the characteristics of the new KOF Barometer are compared to the previous versions and other alternatives.
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the kof economic barometer version 2014
Social Science Research Network, 2014Co-Authors: Klaus Abberger, Michael Graff, Boriss Siliverstovs, Janegbert SturmAbstract:This paper presents a composite leading indicator for the Swiss business cycle corresponding to the growth rate cycle concept. It is the result of a complete overhaul of the KOF Economic Barometer that has been published by the KOF Swiss Economic Institute on a monthly basis since 1976. In line with this tradition, the calculation of the new KOF Barometer comprises two main stages. The first consists of the variable selection procedure; and in the second stage these variables are subsequently transformed into one leading indicator. Whereas in the previous versions of the KOF Barometer six to 25 variables survived the first stage, the new – less discretionary and more automated – version of the first stage is much more generous. Currently, out of a set of 476 variables resulting in 4356 transformations thereof that are tested in the first stage, 219 variables manage to enter the second stage. The increased number of variables underlying the second stage allows a relatively stable and robust KOF Barometer – compared to its previous versions – that has hence no longer to rely on filtering techniques to reduce the noise in the final indicator. In a (pseudo-) real-time analysis the characteristics of the new KOF Barometer are compared to the previous versions and other alternatives.
Keith Putirka - One of the best experts on this subject based on the ideXlab platform.
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A new clinopyroxene-liquid barometer, and implications for magma storage pressures under Icelandic rift zones
American Mineralogist, 2017Co-Authors: David A. Neave, Keith PutirkaAbstract:Pressure is one of the key variables that controls magmatic phase equilibria. However, estimating magma storage pressures from erupted products can be challenging. Various Barometers have been developed over the past two decades that exploit the pressure-sensitive incorporation of jadeite (Jd) into clinopyroxene. These Jd-in-clinopyroxene Barometers have been applied to rift zone magmas from Iceland, where published estimates of magma storage depths span the full thickness of the crust, and extend into the mantle. However, tests performed on commonly used clinopyroxene-liquid Barometers with data from experiments on H 2 O-poor tholeiites in the 1 atm to 10 kbar range reveal substantial pressure-dependent inaccuracies, with some models overestimating pressures of experimental products equilibrated at 1 atm by up to 3 kbar. The pressures of closed-capsule experiments in the 1–5 kbar range are also overestimated, and such errors cannot be attributed to Na loss, as is the case in open furnace experiments. The following barometer was calibrated from experimental data in the 1 atm to 20 kbar range to improve the accuracy of Jd-in-clinopyroxene barometry at pressures relevant to magma storage in the crust: P ( kbar ) = − 26 . 27 + 39 . 16 T ( K ) 10 4 ln [ X Jd Cpx X NaO 0 . 5 liq X AlO 1 . 5 liq ( X SiO 2 liq ) 2 ] − 4 . 22 ln ( X DiHd Cpx ) + 78 . 43 X AlO 1 . 5 liq + 393 . 81 ( X NaO 0 . 5 liq X KO 0 . 5 liq ) 2 This new barometer accurately reproduces its calibration data with a standard error of estimate (SEE) of ±1.4 kbar, and is suitable for use on hydrous and anhydrous samples that are ultramafic to intermediate in composition, but should be used with caution below 1100 °C and at oxygen fugacities greater than one log unit above the QFM buffer. Tests performed using with data from experiments on H 2 O-poor tholeiites reveal that 1 atm runs were overestimated by less than the model precision (1.2 kbar); the new calibration is significantly more accurate than previous formulations. Many current estimates of magma storage pressures may therefore need to be reassessed. To this end, the new barometer was applied to numerous published clinopyroxene analyses from Icelandic rift zone tholeiites that were filtered to exclude compositions affected by poor analytical precision or collected from disequilibrium sector zones. Pressures and temperatures were then calculated using the new barometer in concert with Equation 33 from Putirka (2008). Putative equilibrium liquids were selected from a large database of Icelandic glass and whole-rock compositions using an iterative scheme because most clinopyroxene analyses were too primitive to be in equilibrium with their host glasses. High-Mg# clinopyroxenes from the highly primitive Borgarhraun eruption in north Iceland record a mean storage pressure in the lower crust (5.7 kbar). All other eruptions considered record mean pressures in the mid-crust, with primitive clinopyroxene populations recording slightly higher pressures (3.1–3.6 kbar) than evolved populations (2.6–2.8 kbar). Thus, while some magma processing takes place in the shallow crust immediately beneath Iceland’s central volcanoes, magma evolution under the island’s neovolcanic rift zones is dominated by mid-crustal processes.
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amphibole thermometers and Barometers for igneous systems and some implications for eruption mechanisms of felsic magmas at arc volcanoes
American Mineralogist, 2016Co-Authors: Keith PutirkaAbstract:Calcic, igneous amphiboles are of special interest as their compositional diversity and common occurrence provide ample potential to investigate magmatic processes. But not all amphibole-based Barometers lead to geologically useful information: recent and new tests reaffirm prior studies (e.g., Erdman et al. 2014), indicating that amphibole Barometers are generally unable to distinguish between experiments conducted at 1 atm and at higher pressures, except under highly restrictive conditions. And the fault might not lie with experimental failure. Instead, the problem may relate to an intrinsic sensitivity of amphiboles to temperature ( T ) and liquid composition, rather than pressure. The exceptional conditions are those identified by Anderson and Smith (1995): current amphibole Barometers are more likely to be useful when T Amp = Fe Amp /(Fe Amp +Mg Amp ) Such analysis reveals that amphiboles are vastly less complex than may be inferred from published catalogs of end-member components. Most amphiboles, for example, consist largely of just three components: pargasite [NaCa 2 (Fm 4 Al)Si 6 Al 2 O 22 (OH) 2 ], kaersutite [NaCa 2 (Fm 4 Ti)Si 6 Al 2 O 23 (OH)], and tremolite + ferro-actinolite [Ca 2 Fm 5 Si 8 O 22 (OH) 2 , where Fm = Fe+Mn+Mg]. And nearly all remaining compositional variation can be described with just four others: alumino-tschermakite [Ca 2 (Fm 3 Al 2 )Si 6 Al 2 O 22 (OH) 2 ], a Na-K-gedrite-like component [(Na,K)Fm 6 AlSi 6 Al 2 O 22 (OH) 2 ], a ferri-ferrotschermakite-like component [Ca 2 (Fm 3 Fe 2 3+ )Si 6 Al 2 O 22 (OH) 2 ], and an as yet unrecognized component with 3 to 4 Al atoms per formula unit (apfu), 1 apfu each of Na and Ca, and 4 Ti(Fe 3+ ,Al)Si 5 Al 3 O 23 (OH). None of these components, however, are significantly pressure ( P ) sensitive, leaving the Al-in-amphibole approach, with all its challenges, the best existing hope for an amphibole barometer. A new empirical barometer based on D Al successfully differentiates experimental amphiboles crystallized at 1 to 8 kbar, at least when multiple P estimates, from multiple amphibole compositions, are averaged. Without such averaging however, amphibole barometry is a less certain proposition, providing ±2 kbar precision on individual estimates for calibration data, and ±4 kbar at best for test data; independent checks on P are thus needed. Amphibole compositions, however, provide for very effective thermometers, here based on D Ti , D Na , and amphibole compositions alone, with precisions of ±30 oC. These new models, and tests for equilibrium, are collectively applied to Augustine volcano and the 2010 eruption at Merapi. Both localities reveal a significant cooling and crystallization interval (>190–270 oC) at pressures of 0.75 to 2.2 kbar at Augustine and Merapi, respectively, perhaps the likely depths from which pre-eruption magmas are stored. Such considerable intervals of cooling at shallow depths indicate that mafic magma recharge is not a proximal cause of eruption. Rather, eruption triggering is perhaps best explained by the classic “second boiling” concept, where post-recharge cooling and crystallization drive a magmatic system toward vapor saturation and positive buoyancy.
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thermometers and Barometers for volcanic systems
Reviews in Mineralogy & Geochemistry, 2008Co-Authors: Keith PutirkaAbstract:Knowledge of temperature and pressure, however qualitative, has been central to our views of geology since at least the early 19th century. In 1822, for example, Charles Daubeny presented what may be the very first “Geological Thermometer,” comparing temperatures of various geologic processes (Torrens 2006). Daubeny (1835) may even have been the first to measure the temperature of a lava flow, by laying a thermometer on the top of a flow at Vesuvius—albeit several months following the eruption, after intervening rain (his estimate was 390°F). In any case, pressure ( P ) and temperature ( T ) estimation lie at the heart of fundamental questions: How hot is Earth, and at what rate has the planet cooled. Are volcanoes the products of thermally driven mantle plumes? Where are magmas stored, and how are they transported to the surface—and how do storage and transport relate to plate tectonics? Well-calibrated thermometers and Barometers are essential tools if we are to fully appreciate the driving forces and inner workings of volcanic systems. This chapter presents methods to estimate the P-T conditions of volcanic and other igneous processes. The coverage includes a review of existing geothermometers and geoBarometers, and a presentation of approximately 30 new models, including a new plagioclase-liquid hygrometer. Our emphasis is on experimentally calibrated “thermoBarometers,” based on analytic expressions using P or T as dependent variables. For numerical reasons (touched on below) such expressions will always provide the most accurate means of P-T estimation, and are also most easily employed. Analytical expressions also allow error to be ascertained; in the absence of estimates of error, P-T estimates are nearly meaningless. This chapter is intended to complement the chapters by Anderson et al. (2008), who cover granitic systems, and by Blundy and Cashman (2008) and Hansteen and Klugel (2008), who consider additional methods …
Pruitt Jane - One of the best experts on this subject based on the ideXlab platform.
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COVID-19 und aktuelle Herausforderungen in Schule und Bildung. Erste Befunde des Schul-Barometers in Deutschland, Österreich und der Schweiz
pedocs-Dokumentenserver DIPF, 2020Co-Authors: Huber, Stephan Gerhard, Günther, Paula Sophie, Schneider Nadine, Helm Christoph, Schwander Marius, Schneider, Julia A., Pruitt JaneAbstract:Die aktuelle Situation ist gekennzeichnet durch die durch das COVID-19-Virus ausgelöste gesellschaftliche Krise mit weitreichenden Auswirkungen auf nahezu alle gesellschaftlichen Bereiche. Die Schulen wurden in Deutschland, Österreich und der Schweiz ab Mitte März geschlossen (...). Die Bundesländer in Deutschland sind zunächst sehr unterschiedlich vorgegangen, ebenso in der Schweiz die verschiedenen Kantone, z.B. hinsichtlich Ferienregelungen, unterschiedlichen Formen der Betreuung und der Anwesenheit von schulischen Mitarbeitenden sowie hinsichtlich der Lehr-Lern-Arrangements (zunächst Aufgaben zur Wiederholung und noch kein weiterer neuer Unterrichtsstoff). Ziel des Schul-Barometers ist die Beschreibung der aktuellen Schulsituation in Deutschland, Österreich und der Schweiz aus Sicht verschiedener Personengruppen. Damit soll ein Beitrag zum Erfahrungsaustausch geleistet werden im Sinne von „Responsible Science“ in der Beschreibung der Krisensituation und der Auswirkungen auf Schule und Bildung. Das Schul-Barometer wurde in der Zeit vom 24. März bis 5. April 2020 durchgeführt. Zu den Befragten gehören Schülerinnen und Schüler, Eltern, Schulleitung, Lehrerinnen und Lehrer, Sonderpädagoginnen und Sonderpädagogen, Sozialpädagoginnen und Sozialpädagogen, Erzieherinnen und Erzieher, Vertreterinnen und Vertreter der Schulverwaltung/Schulaufsicht, Personen aus Unterstützungssystemen (z.B. Fort-/Weiterbildung, Schulentwicklungsbegleitung). Befragt wurden 7.116 Personen. Das Schul-Barometer umfasst u.a. die Themen: Aktuelle häusliche Lebenssituation von Schülerinnen und Schülern; Belastungssituation von Eltern und Schule; Betreuungssituation von Schülerinnen und Schülern; Informationsfluss Behörde-Schule-Eltern und zwischen Mitarbeitenden der Schule und Schülerinnen und Schülern; Digitale Lehr-Lern-Formate: Erfahrungen und Empfehlungen; Rolle der Schulleitung; Rolle, Motivation, Kompetenzen von Mitarbeitenden der Schule; Bedarfe, Bedürfnisse, Wünsche aus Sicht von Eltern, Schülerinnen und Schülern, Mitarbeitenden der Schule, Schulleitungen, Vertreterinnen und Vertretern von Behörden/Verwaltung sowie Unterstützungssystemen. (DIPF/Orig.
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COVID-19: Fernunterricht aus Sicht der Mitarbeitenden von Schulen in Deutschland, Österreich und der Schweiz
Universität Bielefeld - Wissenschaftliche Einrichtung Oberstufen-Kolleg & Bielefeld School of Education, 2020Co-Authors: Huber, Stephan Gerhard, Schneider Nadine, Helm Christoph, Schwander Marius, Pruitt Jane, Günther, Paula S., Schneider, Julia AlexandraAbstract:Im Zuge der Corona-Pandemie wurden weltweit temporären Schulschließungen vorgenommen. Wie funktioniert(e) Bildung in dieser Krise? Daten des Schul-Barometers von insgesamt 5.167 Mitarbeitenden an Schulen aus Deutschland, Österreich und der Schweiz ermöglichen einen Einblick in die Rahmenbedingungen von Digitalisierung während des Lehrens und Lernens während der Schulschließung. Die Daten bestätigen den „digital divide“ in den Kompetenzen und Erfahrungen der Lehrkräfte. Lehrkräfte in Österreich und der Schweiz schätzen ihre digitalen Kompetenzen höher ein als deutsche Mitarbeitende. Die technische Ausstattung wird von Befragten aus Österreich und der Schweiz ebenfalls besser eingeschätzt als in Deutschland. Die Kooperation zwischen Mitarbeitenden der Schule selbst sowie mit Eltern und ein stärkerer Fokus auf die Beziehungsebene zu Schüler*innen wird in Zeiten der Krise trotz und wegen der Distanz noch bedeutsamer für Lehre und Lernen. Perspektivisch können aus den Daten des Schul-Barometers Empfehlungen für die „Schule von morgen“ abgeleitet werden
Yannis Siskos - One of the best experts on this subject based on the ideXlab platform.
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customer satisfaction evaluation methods for measuring and implementing service quality
2012Co-Authors: Evangelos Grigoroudis, Yannis SiskosAbstract:Basic Methodological Approaches.- Other Methodological Approaches.- MUSA: Multicriteria Satisfaction Analysis.- Extensions of the MUSA Method.- Advanced Topics on the MUSA Method.- Customer Satisfaction Surveys and Barometers.- Applications in Business Organizations.- Customer Satisfaction and Information Systems.
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customer satisfaction surveys and Barometers
2010Co-Authors: Evangelos Grigoroudis, Yannis SiskosAbstract:Customer satisfaction research methodologies may be divided, according to their content and objectives, into qualitative and quantitative research (Dutka, 1995).
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A survey of customer satisfaction Barometers: Some results from the transportation-communications sector
European Journal of Operational Research, 2004Co-Authors: Evangelos Grigoroudis, Yannis SiskosAbstract:Abstract The most important efforts that have been reported for the development of generic satisfaction Barometers during the last years refer to individual business organisations, industry sectors or the total of national economies. The main aim of these efforts is the data collection either for comparative analysis of companies’ performance regarding customer satisfaction or for monitoring the evolution of global and partial satisfaction indices. In addition, the generic satisfaction Barometers provide the ability to correlate basic economical dimensions with customer satisfaction like productivity variations at a national level or changes in the general consumer price index. This study presents the most important efforts for the measurement of customer satisfaction at the transportation-communications sector within the frame of development and installation of national satisfaction Barometers. Furthermore, the models, which constitute the basic methodological tools for the measurement and the analysis of the presented satisfaction Barometers, are briefly presented through this paper.