80 research outputs found

    Seismogenic structure and processes associated with magma inflation and hydrothermal circulation beneath the East Pacific Rise at 9°50′N

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    A dense ocean bottom seismometer array recorded more than 7,300 microearthquakes between October 2003 and April 2004 on the fast spreading East Pacific Rise at 9°50′ N. A previous initial analysis of these data revealed the general structure of an along-axis oriented hydrothermal circulation cell, with an inferred down-flow zone near a 4th-order axial discontinuity, a horizontal band of seismicity overlying the axial magma chamber (AMC), and an upflow zone that correlates with activity patterns of hydrothermal vents. Here we present cross-correlation-based double-difference hypocenter locations that reveal further insight into the detailed structure and kinematics that control seismic failure. We find that the majority of events within the inferred down flow pipe occur near the surface where the entrenched seawater presumably lowers the frictional strength of faults generated by local tectonic stresses. Beneath the eastern side of the ridge axis, just above the AMC at ∼1.4 km depth, we observe repeated shear failure along well defined steeply east dipping faults. Composite focal mechanisms indicate reverse motion, suggesting that slip on these faults is caused by AMC inflation and possibly injection of magma into a narrow sill. We resolve a small counterclockwise skew in the strike of the reverse faults relative to the direction of the ridge axis, consistent with Nuvel 1A spreading direction suggesting that the regional tectonic stress field may be controlling the seismogenic structures at depth. Earthquakes on the reverse faults occur preferentially during peak extensional tidal stresses, indicating that these faults are critically stressed

    Hydrothermally-induced melt lens cooling and segmentation along the axis of fast- and intermediate-spreading centers

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    Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 38 (2011): L14307, doi:10.1029/2011GL047798.The heat output and thermal regime of fast and intermediate spreading centers are strongly controlled by boundary layer processes between the hydrothermal system and the underlying crustal magma chamber (AMC), which remain to be fully understood. Here, we model the interactions between a shallow two-dimensional cellular hydrothermal system at temperatures <700°C, and a deeper AMC at temperatures up to 1200°C. We show that hydrothermal cooling can freeze the AMC in years to decades, unless melt injections occur on commensurate timescales. Moreover, the differential cooling between upflow and downflow zones can segment the AMC into mush and melt regions that alternate on sub-kilometric length scales. These predictions are consistent with along-axis variations in AMC roof depth observed in ophiolites and oceanic settings. In this respect, fine-scale geophysical investigations of the structure of AMCs may help constrain hydrothermal recharge locations associated with active hydrothermal sites

    The Youngest Victims: Children and Youth Affected by War

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    In 1989, the United Nation Convention on the Rights of the Child declared, “[state parties] shall take all feasible measures to ensure protection and care of children who are affected by an armed conflict.” In addition to attempting to secure the welfare of children in armed conflict, the Convention went on to ban the recruitment and deployment of children during armed conflict. Despite the vast majority of sovereign nations signing and ratifying this agreement, this treaty, unfortunately, has not prevented children and youth from witnessing, becoming victims of, or participating in political, ethnic, religious, and cultural violence across the past three decades. This chapter offers an “ecological perspective” on the psychosocial consequences of exposure to the trauma of war-related violence and social disruption

    A many-analysts approach to the relation between religiosity and well-being

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    The relation between religiosity and well-being is one of the most researched topics in the psychology of religion, yet the directionality and robustness of the effect remains debated. Here, we adopted a many-analysts approach to assess the robustness of this relation based on a new cross-cultural dataset (N=10,535 participants from 24 countries). We recruited 120 analysis teams to investigate (1) whether religious people self-report higher well-being, and (2) whether the relation between religiosity and self-reported well-being depends on perceived cultural norms of religion (i.e., whether it is considered normal and desirable to be religious in a given country). In a two-stage procedure, the teams first created an analysis plan and then executed their planned analysis on the data. For the first research question, all but 3 teams reported positive effect sizes with credible/confidence intervals excluding zero (median reported β=0.120). For the second research question, this was the case for 65% of the teams (median reported β=0.039). While most teams applied (multilevel) linear regression models, there was considerable variability in the choice of items used to construct the independent variables, the dependent variable, and the included covariates

    A Many-analysts Approach to the Relation Between Religiosity and Well-being

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    The relation between religiosity and well-being is one of the most researched topics in the psychology of religion, yet the directionality and robustness of the effect remains debated. Here, we adopted a many-analysts approach to assess the robustness of this relation based on a new cross-cultural dataset (N = 10, 535 participants from 24 countries). We recruited 120 analysis teams to investigate (1) whether religious people self-report higher well-being, and (2) whether the relation between religiosity and self-reported well-being depends on perceived cultural norms of religion (i.e., whether it is considered normal and desirable to be religious in a given country). In a two-stage procedure, the teams first created an analysis plan and then executed their planned analysis on the data. For the first research question, all but 3 teams reported positive effect sizes with credible/confidence intervals excluding zero (median reported β = 0.120). For the second research question, this was the case for 65% of the teams (median reported β = 0.039). While most teams applied (multilevel) linear regression models, there was considerable variability in the choice of items used to construct the independent variables, the dependent variable, and the included covariates

    The ATLAS fast tracKer system

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    The ATLAS Fast TracKer (FTK) was designed to provide full tracking for the ATLAS high-level trigger by using pattern recognition based on Associative Memory (AM) chips and fitting in high-speed field programmable gate arrays. The tracks found by the FTK are based on inputs from all modules of the pixel and silicon microstrip trackers. The as-built FTK system and components are described, as is the online software used to control them while running in the ATLAS data acquisition system. Also described is the simulation of the FTK hardware and the optimization of the AM pattern banks. An optimization for long-lived particles with large impact parameter values is included. A test of the FTK system with the data playback facility that allowed the FTK to be commissioned during the shutdown between Run 2 and Run 3 of the LHC is reported. The resulting tracks from part of the FTK system covering a limited η-ϕ region of the detector are compared with the output from the FTK simulation. It is shown that FTK performance is in good agreement with the simulation. © The ATLAS collaboratio

    Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

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    Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

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    The impact of disclosing emotions on ratings of interpersonal closeness, warmth, competence, and leadership ability

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    IntroductionIncreasingly, business leaders and other professionals are called upon to be vulnerable and authentic in the workplace, which often includes disclosing emotions to others. While sharing emotions is known to enhance closeness, several questions remain underexplored. Specifically, disclosing personal facts about oneself and disclosing emotions have often been studied together, making it difficult to determine the effects of disclosing emotions per se. Moreover, not enough is known about factors that may influence effects of disclosing emotions, including recipients’ attitudes toward emotion-sharing, the sharer’s gender, and whether one considers the disclosure to be similar to one’s own experiences. We examined the impact of disclosing positive and negative emotion on ratings of closeness, warmth, competence, and leadership ability.Methods119 participants (95 female) in the United States were shown headshots of individuals who were introduced in the first person in written format. For half of the pictures, an autobiographical fact about the individual’s past was disclosed. For the other half, an autobiographical fact and an associated emotion were disclosed.ResultsWe found that sharing both positive and negative emotions increased feelings of closeness above and beyond the effects of autobiographical sharing alone. Sharing positive emotions also increased ratings of warmth, competence, and leadership ability. Male and female sharers benefited equally from disclosing emotions and effects were largely robust to recipients’ attitudes toward emotional expression. Having something in common with the disclosed fact or emotion further increased all ratings.ConclusionThese findings indicate that disclosing emotions may improve interpersonal interactions, with potential management applications in business
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