Transient Creep in Subduction Zones by Long-Range Dislocation Interactions in Olivine

Large earthquakes transfer stress from the shallow lithosphere to the underlying viscoelastic lower crust and upper mantle, inducing transient creep during the postseismic interval. Recent experiments on olivine have provided a new rheological model for this transient creep based on accumulation and release of back stresses among dislocations. Here, we test whether natural rocks preserve dislocation-induced stress heterogeneity consistent with the back-stress hypothesis by mapping olivine from the palaeosubduction interface of the Oman-UAE ophiolite with high-angular resolution electron backscatter diffraction. The olivine preserves heterogeneous residual stresses that vary in magnitude by several hundred megapascals over length scales of a few micrometres. Large stresses are commonly spatially associated with elevated densities of geometrically necessary dislocations within subgrain interiors. These spatial relationships, along with characteristic probability distributions of the stresses, confirm that the stress heterogeneity is generated by the dislocations and records their long-range elastic interactions. Images of dislocations decorated by oxidation display bands of high and low dislocation density, suggesting that dislocation interactions contributed to organisation of the substructure. These results support the applicability of the back-stress model of transient creep to deformation in the mantle portion of plate-boundary shear zones. The model predicts that rapid stress changes, such as those imposed by large earthquakes, can induce order-of-magnitude changes in viscosity that depend nonlinearly on the stress change, consistent with inferences of mantle rheology from geodetic observations.This work was supported by the Natural Environment Research Council, grant NE/M000966/1; the Netherlands Organisation for Scientific Research, User Support Programme Space Research, grant ALWGO.2018.038; and startup funds from Utrecht University

Matrix-assisted laser-desorption/ionization BIOTYPER: experience in the routine of a University hospital

AbstractMatrix-assisted laser-desorption/ionization time-of-flight (MALDI-TOF) is positioned at the forefront of bacterial identification in the future. Its performance needed to be evaluated in a routine Bacteriology laboratory to determine its true benefits. A prospective study was carried out in the Bacteriology laboratory of the Pellegrin University Hospital in Bordeaux, France, from April to May 2009. Bacterial isolates from clinical samples were identified by conventional phenotypic bacteriological methods [Phoenix (Becton-Dickinson) or API strips (bioMérieux)] and in parallel with a mass spectrometer (Ultraflex III TOF/TOF and the biotyper database from Bruker Daltonics). In case of a discrepancy between these results at the genus level, a 16S rRNA and/or rpoB gene sequencing was performed. Of the 1013 bacteria tested, 837 (82.6%) were correctly identified at the species level by MALDI-TOF mass spectrometry (MS) without extraction and 189 after extraction, i.e. 986 (97.3%) were correctly identified at the species level by MALDI-TOF MS, vs. 945 (93.2%) by phenotypic methods. Indeed, the extraction step was necessary for only 15% of the isolates. These results were even better when considering the genus, reaching almost 99% with MALDI-TOF MS and 98% with phenotypic methods. The performance of MALDI-TOF MS is very attractive considering its efficiency and rapidity, and the technique constitutes a precious tool for bacteriological identification in a routine laboratory

Acute Traumatic Stress Screening Can Identify Patients and Their Partners at Risk for Posttraumatic Stress Disorder Symptoms After a Cardiac Arrest:A Multicenter Prospective Cohort Study

BACKGROUND: Posttraumatic stress disorder (PTSD) is prevalent in patients who have had a cardiac arrest and their partners. Accordingly, acute traumatic stress screening is recommended, but its association with later PTSD symptoms has never been addressed in postresuscitation settings. OBJECTIVE: The aim of this study was to examine whether acute traumatic stress is associated with PTSD symptoms in patients who have had a cardiac arrest and their partners. METHODS: This multicenter longitudinal study of 141 patients and 97 partners measures acute traumatic stress at 3 weeks and PTSD symptoms at 3 months and 1 year after resuscitation, using the Impact of Event Scale. Linear regression models were used to evaluate the association between severity of acute traumatic stress and PTSD symptoms and post hoc to explore effects of group (patients/partners), age, and sex on acute traumatic stress severity. We categorized Impact of Event Scale scores higher than 26 at 3 months and 1 year as clinical severe PTSD symptoms. RESULTS: Higher acute traumatic stress severity is significantly positively associated with higher PTSD symptom severity at 3 months (patients and partners: P < .001) and 1 year (patients and partners: P < .001) postresuscitation, with the strongest association for women compared with men (P = .03). Acute traumatic stress was higher in women compared with men across groups (P = .02). Clinical severe PTSD symptoms were present in 26% to 28% of patients and 45% to 48% of partners. CONCLUSION: Experiencing a cardiac arrest may elicit clinical severe PTSD symptoms in patients, but particularly in their partners. Screening patients and partners for acute traumatic stress postresuscitation is warranted to identify those at increased risk of long-term PTSD symptoms

Active Object Search Exploiting Probabilistic Object–Object Relations

\u3cp\u3eThis paper proposes a probabilistic object-object relation based approach for an active object search. An important role of mobile robots will be to perform object-related tasks and active object search strategies deal with the non-trivial task of finding an object in unstructured and dynamically changing environments. This work builds further upon an existing approach exploiting probabilistic object-room relations for selecting the room in which an object is expected to be. Learnt object-object relations allow to search for objects inside a room via a chain of intermediate objects. Simulations have been performed to investigate the effect of the camera quality on path length and failure rate. Furthermore, a comparison is made with a benchmark algorithm based the same prior knowledge but without using a chain of intermediate objects. An experiment shows the potential of the proposed approach on the AMIGO robot.\u3c/p\u3

Social networks in relation to self-reported symptomatic infections in individuals aged 40-75 - the Maastricht study.

Most infections are spread through social networks (detrimental effect). However, social networks may also lower infection acquisition (beneficial effect). This study aimed to examine associations between social network parameters and prevalence of self-reported upper and lower respiratory, gastrointestinal and urinary tract infections in a population aged 40-75

Learning to Teach About Ideas and Evidence in Science : The Student Teacher as Change Agent

A collaborative curriculum development project was set up to address the lack of good examples of teaching about ideas and evidence and the nature of science encountered by student teachers training to teach in the age range 11-16 in schools in England. Student and teacher-mentor pairs devised, taught and evaluated novel lessons and approaches. The project design required increasing levels of critique through cycles of teaching, evaluation and revision of lessons. Data were gathered from interviews and students' reports to assess the impact of the project on student teachers and to what extent any influences survived when they gained their first teaching posts. A significant outcome was the perception of teaching shifting from the delivery of standard lessons in prescribed ways to endeavours demanding creativity and decision-making. Although school-based factors limited newly qualified teachers' chances to use new lessons and approaches and therefore act as change-agents in schools, the ability to critique curriculum materials and the recognition of the need to create space for professional dialogue were durable gains

Association Between Employment Status and Objectively Measured Physical Activity and Sedentary BehaviorThe Maastricht Study

Objective:To examine the association between employment status and physical activity and sedentary behavior.Methods:We included 2045 participants from The Maastricht Study, who used a thigh-worn accelerometer. We compared time spent sedentary, standing, stepping, and higher intensity physical activity between participants with different employment status (non-employed or low-, intermediate- or high-level occupation) with analysis of variance.Results:Participants in low-level occupations were less sedentary and standing and stepping more than those in other occupational categories and non-employed participants. Among the employed, the differences were mostly observed on weekdays, whereas the differences in sedentary time and standing between those in low-level occupations and non-employed participants were evident both on weekdays and weekend days.Conclusions:Those in low-level occupational category were less sedentary and more active than non-employed and those in other occupational categories, especially on weekdays