641 research outputs found

    Moment tensor inversions of icequakes on Gornergletscher, Switzerland

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    We have determined seismic source mechanisms for shallow and intermediate-depth icequake clusters recorded on the glacier Gornergletscher, Switzerland, during the summers of 2004 and 2006. The selected seismic events are part of a large data set of over 80,000 seismic events acquired with a dense seismic network deployed in order to study the yearly rapid drainage of Gornersee lake, a nearby ice-marginal lake. Using simple frequency and distance scaling and Green’s functions for a homogeneous half-space, we calculated moment tensor solutions for icequakes with M_w-1.5 using a full-waveform inversion method usually applied to moderate seismic events (M_w>4) recorded at local to regional distances (≈50–700 km). Inversions from typical shallow events are shown to represent tensile crack openings. This explains well the dominating Rayleigh waves and compressive first motions observed at all recording seismograms. As these characteristics can be observed in most icequake signals, we believe that the vast majority of icequakes recorded in the 2 yr is due to tensile faulting, most likely caused by surface crevasse openings. We also identified a shallow cluster with somewhat atypical waveforms in that they show less dominant Rayleigh waves and quadrantal radiation patterns of first motions. Their moment tensors are dominated by a large double-couple component, which is strong evidence for shear faulting. Although less than a dozen such icequakes have been identified, this is a substantial result as it shows that shear faulting in glacier ice is generally possible even in the absence of extreme flow changes such as during glacier surges. A third source of icequakes was located at 100 m depth. These sources can be represented by tensile crack openings. Because of the high-hydrostatic pressure within the ice at these depths, these events are most likely related to the presence of water lenses that reduce the effective stress to allow for tensile faulting

    How to keep drivers engaged while supervising driving automation? A literature survey and categorization of six solution areas

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    This work aimed to organise recommendations for keeping people engaged during human supervision of driving automation, encouraging a safe and acceptable introduction of automated driving systems. First, heuristic knowledge of human factors, ergonomics, and psychological theory was used to propose solution areas to human supervisory control problems of sustained attention. Driving and non-driving research examples were drawn to substantiate the solution areas. Automotive manufacturers might (1) avoid this supervisory role altogether, (2) reduce it in objective ways or (3) alter its subjective experiences, (4) utilize conditioning learning principles such as with gamification and/or selection/training techniques, (5) support internal driver cognitive processes and mental models and/or (6) leverage externally situated information regarding relations between the driver, the driving task, and the driving environment. Second, a cross-domain literature survey of influential human-automation interaction research was conducted for how to keep engagement/attention in supervisory control. The solution areas (via numeric theme codes) were found to be reliably applied from independent rater categorisations of research recommendations. Areas (5) and (6) were addressed by around 70% or more of the studies, areas (2) and (4) in around 50% of the studies, and areas (3) and (1) in less than around 20% and 5%, respectively. The present contribution offers a guiding organisational framework towards improving human attention while supervising driving automation.submittedVersio

    Microseismic joint location and anisotropic velocity inversion for hydraulic fracturing in a tight Bakken reservoir

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    To improve the accuracy of microseismic event locations, we developed a new inversion method with double-difference constraints for determining the hypocenters and the anisotropic velocity model for unconventional reservoirs. We applied this method to a microseismic data set monitoring a Middle Bakken completion in the Beaver Lodge area of North Dakota. Geophone arrays in four observation wells improved the ray coverage for the velocity inversion. Using an accurate anisotropic velocity model is important to correctly assess the height growth of the hydraulically induced fractures in the Middle Bakken. Our results showed that (1) moderate-to-strong anisotropy exists in all studied sedimentary layers, especially in the Upper and Lower Bakken shale formations, where the Thomsen parameters (ϵ and γ) can be greater than 0.4, (2) all the events selected for high signal-to-noise ratio and used for the joint velocity inversion are located in the Bakken and overlying Lodgepole formations, i.e., no events are detected in the Three Forks formation below the Bakken, and (3) more than half of the strong events are in two clusters at approximately 100 and 150 m above the Middle Bakken. Reoccurrence of strong, closely clustered events suggested activation of natural fractures or faults in the Lodgepole formation. The sensitivity analysis for the inversion results showed that the relative uncertainty in parameter δ is larger than other anisotropy parameters. The microseismic event locations and the anisotropic velocity model are validated by comparing synthetic and observed seismic waveforms and by S-wave splitting.Shell Oil Compan

    EASIX for Prediction of Outcome in Hospitalized SARS-CoV-2 Infected Patients

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    Background: The coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and has evoked a pandemic that challenges public health-care systems worldwide. Endothelial cell dysfunction plays a key role in pathophysiology, and simple prognosticators may help to optimize allocation of limited resources. Endothelial activation and stress index (EASIX) is a validated predictor of endothelial complications and outcome after allogeneic stem cell transplantation. Aim of this study was to test if EASIX could predict life-threatening complications in patients with COVID-19. Methods: SARS-CoV-2-positive, hospitalized patients were enrolled onto a prospective non-interventional register study (n=100). Biomarkers were assessed at hospital admission. Primary endpoint was severe course of disease (mechanical ventilation and/or death, V/D). Results were validated in 126 patients treated in two independent institutions. Results: EASIX at admission was a strong predictor of severe course of the disease (odds ratio for a two-fold change 3.4, 95%CI 1.8-6.3, p<0.001), time to V/D (hazard ratio (HR) for a two-fold change 2.0, 95%CI 1.5-2.6, p<0.001) as well as survival (HR for a two-fold change 1.7, 95%CI 1.2-2.5, p=0.006). The effect was retained in multivariable analysis adjusting for age, gender, and comorbidities and could be validated in the independent cohort. At hospital admission EASIX correlated with increased suppressor of tumorigenicity-2, soluble thrombomodulin, angiopoietin-2, CXCL8, CXCL9 and interleukin-18, but not interferon-alpha. Conclusion: EASIX is a validated predictor of COVID19 outcome and an easy-to-access tool to segregate patients in need for intensive surveillance

    The Race to Leadership Effectiveness: A Study on School Organization for High and Low Performing Georgia Schools

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    With the adoption of such initiatives as No Child Left Behind (NCLB), Common Core State Standards (CCSS), and the College and Career Readiness Performance Index (CCRPI), there is increasing pressure for students to meet and exceed performance expectations. This is easier said than done, especially given that not all organizational structures are helpful to student performance. A quantitative, correlational study was done to determine the relationship between school organization and school performance within Georgia schools. Subgroup comparisons between high and low performing schools were included in analyses. Results showed that high organizational effectiveness was associated with high student performance outcomes. High performing schools had significantly higher organizational effectiveness than low performing schools. The findings of this study help teachers, administrators, and policy makers determine essential organizational themes that help students succeed. The use of positive organizational characteristics is encouraged in order for students to have much better success moving forward

    Sommergrundlinien 2010

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    Das DIW Berlin prognostiziert ein Wirtschaftswachstum von 1,9 Prozent im Jahresdurchschnitt 2010 und 1,7 Prozent im Jahresdurchschnitt 2011. Die Inflation bleibt mit knapp 1,5 Prozent im Prognosezeitraum moderat. Nach einem schwachen ersten Quartal, in dem die konjunkturelle Entwicklung durch das Auslaufen von stimulierenden Maßnahmen und durch ungünstige Wetterbedingungen gehemmt wurde, erlebt die deutsche Wirtschaft ab dem zweiten Quartal einen stärkeren Aufschwung als ursprünglich erwartet. Dabei sind 2010 vor allem die Exporte für die wirtschaftliche Erholung verantwortlich. Erst 2011 wird das Wachstum von einer wieder erstarkten Binnennachfrage getragen werden. Die Zuwächse bei den Exporten sind einer stark wachsenden Weltwirtschaft zu verdanken. Wie schon in den vergangenen Jahren expandieren die Schwellenländer, darunter insbesondere China und Indien, besonders kräftig. Aber auch die von der Krise stark getroffenen entwickelten Volkswirtschaften Japan und USA erholen sich unerwartet schnell. Weniger robust ist das Wachstum in Europa. Nicht nur die Verunsicherung im Zuge der Schuldenkrise, sondern auch die absehbare notwendige Konsolidierung der öffentlichen Haushalte schwächt hier die Konjunktur. Risiko für die weltwirtschaftliche Entwicklung geht zusätzlich von einer zu beobachtenden neuen Blasenbildung auf den Vermögensmärkten in einigen Schwellenländern - insbesondere in China - aus. Die Binnennachfrage in Deutschland wird 2010 nur leichte Zuwächse verzeichnen und erst 2011 das Wirtschaftswachstum ankurbeln können. Investoren halten sich angesichts des ungewissen Aufschwungs und der geringen Kapazitätsauslastung zurück. Auch der private Verbrauch wird durch das Auslaufen von Stützungsmaßnahmen, die Verunsicherung durch die Schuldenkrise und nur geringe Einkommenszugewinne gehemmt. Die Entwicklung auf dem Arbeitsmarkt ist vor allem im Dienstleistungssektor positiv, ein spürbarer Rückgang der Arbeitslosigkeit dürfte aber nicht vor 2011 einsetzen. Obwohl das Defizit des öffentlichen Haushalts in diesem Jahr niedriger ausfällt als erwartet, besteht kein Grund zur Entwarnung. Ein Großteil des Defizits ist strukturell bedingt und wird eine energische Konsolidierung erforderlich machen. Die von der Bundesregierung eingeleiteten Schritte sind hierfür keinesfalls ausreichend. Für die Zukunft werden sowohl eine Kürzung der Staatsausgaben, etwa bei Subventionen, als auch Steuererhöhungen notwendig sein, um die öffentlichen Haushalte ins Gleichgewicht zu bringen.Business cycle forecast, Economic outlook

    Hematopoietic stem cell transplantation in Europe 2014: More than 40 000 transplants annually

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    A record number of 40 829 hematopoietic stem cell transplantation (HSCT) in 36 469 patients (15 765 allogeneic (43%), 20 704 autologous (57%)) were reported by 656 centers in 47 countries to the 2014 survey. Trends include: continued growth in transplant activity, more so in Eastern European countries than in the west; a continued increase in the use of haploidentical family donors (by 25%) and slower growth for unrelated donor HSCT. The use of cord blood as a stem cell source has decreased again in 2014. Main indications for HSCT were leukemias: 11 853 (33%; 96% allogeneic); lymphoid neoplasias; 20 802 (57%; 11% allogeneic); solid tumors; 1458 (4%; 3% allogeneic) and non-malignant disorders; 2203 (6%; 88% allogeneic). Changes in transplant activity include more allogeneic HSCT for AML in CR1, myeloproliferative neoplasm (MPN) and aplastic anemia and decreasing use in CLL; and more autologous HSCT for plasma cell disorders and in particular for amyloidosis. In addition, data on numbers of teams doing alternative donor transplants, allogeneic after autologous HSCT, autologous cord blood transplants are presented
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