193 research outputs found

    Mapping a hidden terrane boundary in the mantle lithosphere with lamprophyres

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    Traces of ancient mafic layers in the Tethys oceanic mantle

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    Oceanic basalts are formed by melting of a chemically and isotopically heterogeneous mantle source. The oceanic mantle probably resembles a marble cake containing layers of mafic rock - perhaps recycled ocean crust - stored in the mantle for >1 billion years. Many questions about the nature and distribution of these mantle heterogeneities remain. Here we show that lithological and isotopic traces of ancient mafic layers can still be seen in mantle rocks that have melted to form oceanic crust at a spreading centre in the Tethys Ocean. We have found centimetre-scale heterogeneity in initial osmium isotope ratios in mantle rocks from the Pindos Ophiolite. Deformed pyroxenite layers have high 187Os/188Os ratios (0.14-0.20) compared to adjacent host peridotites (187Os/188Os: 0.12-0.13). These layers were formed by a reaction between mantle rock and melt derived from ancient rocks with high Re/Os ratios. We interpret the pyroxenite layers as the wall rocks of billion-year old mafic layers that melted and transformed adjacent mantle peridotite into pyroxenite by melt-rock reaction. The pyroxenite layers are the relics of ancient metre-scale basaltic veins in a kilometre-sized marble cake domain in the oceanic mantle that has withstood homogenization on a billion-year time scale. © 2013

    Pretreatment organ function in patients with advanced head and neck cancer: clinical outcome measures and patients' views

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    <p>Abstract</p> <p>Background</p> <p>Aim of this study is to thoroughly assess pretreatment organ function in advanced head and neck cancer through various clinical outcome measures and patients' views.</p> <p>Methods</p> <p>A comprehensive, multidimensional assessment was used, that included quality of life, swallowing, mouth opening, and weight changes. Fifty-five patients with stage III-IV disease were entered in this study prior to organ preserving (chemoradiation) treatment.</p> <p>Results</p> <p>All patients showed pretreatment abnormalities or problems, identified by one or more of the outcome measures. Most frequent problems concerned swallowing, pain, and weight loss. Interestingly, clinical outcome measures and patients' perception did no always concur. E.g. videofluoroscopy identified aspiration and laryngeal penetration in 18% of the patients, whereas only 7 patients (13%) perceived this as problematic; only 2 out of 7 patients with objective trismus actually perceived trismus.</p> <p>Conclusion</p> <p>The assessment identified several problems already pre-treatment, in this patient population. A thorough assessment of both clinical measures and patients' views appears to be necessary to gain insight in all (perceived) pre-existing functional and quality of life problems.</p

    Neck Pain and Disability Scale and the Neck Disability Index: reproducibility of the Dutch Language Versions

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    The first aim of this study was to translate the Neck Pain and Disability Scale (NPAD) from English into Dutch producing the NPAD–Dutch Language Version (DLV). The second aim was to analyze test–retest reliability and agreement of the NPAD–DLV and the Neck Disability Index (NDI)–DLV. The NPAD was translated according to established guidelines. Thirty-four patients (mean age 37.5 years, 68% female) with chronic neck pain (CNP), within an outpatient rehabilitation setting, participated in this study. The NPAD–DLV and the NDI–DLV were filled out twice with a mean test–retest interval of 18 days. The intraclass correlation coefficient of the NPAD–DLV was 0.76 (95% confidence interval (CI) 0.57–0.87) and of the NDI–DLV 0.84 (95% CI 0.69–0.92). The limits of agreement of the NPAD–DLV and the NDI–DLV were, respectively, ±20.9 (scale 0–100) and ±6.5 (scale 0–50). The reliability of the NPAD–DLV and the NDI–DLV was acceptable for patients with CNP. The variation (‘instability’) in the NPAD–DLV total scores was relatively large and larger than the variation of the NDI–DLV

    Staying Cool Across the First Year of Middle School

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    As students transition into middle school they must successfully negotiate a new, larger peer context to attain or maintain high social standing. The goal of this study was to examine the extent to which the maintenance, attainment, and loss of a cool status over the course of the sixth grade is associated with student and classroom levels of physical, verbal, and relational aggression. To address this goal, we studied a sample of 1985 (55% girls) ethnically diverse adolescents from 99 sixth grade classrooms in the United States. Attaining a cool status at any point across the school year was associated with stronger aggressive reputations. Additionally, classroom norms for aggressive behavior moderated the association between changes in aggression over the school year and the stability of coolness such that students who maintained their coolness across the school year showed greater increases in their verbally aggressive reputations from fall to spring when they were in classrooms with higher levels of aggression. The findings illustrate the importance of fitting in with social norms for maintaining a high social status among a new set of peers in middle school

    Communication, advice exchange and job satisfaction of nursing staff: a social network analyses of 35 long-term care units

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    Background: The behaviour of individuals is affected by the social networks in which they are embedded. Networks are also important for the diffusion of information and the influence of employees in organisations. Yet, at the moment little is known about the social networks of nursing staff in healthcare settings. This is the first study that investigates informal communication and advice networks of nursing staff in long-term care. We examine the structure of the networks, how they are related to the size of units and characteristics of nursing staff, and their relationship with job satisfaction. Methods: We collected social network data of 380 nursing staff of 35 units in group projects and psychogeriatric units in nursing homes and residential homes in the Netherlands. Communication and advice networks were analyzed in a social network application (UCINET), focusing on the number of contacts (density) between nursing staff on the units. We then studied the correlation between the density of networks, size of the units and characteristics of nursing staff. We used multilevel analyses to investigate the relationship between social networks and job satisfaction of nursing staff, taking characteristics of units and nursing staff into account. Results: Both communication and advice networks were negatively related to the number of residents and the number of nursing staff of the units. Communication and advice networks were more dense when more staff worked part-time. Furthermore, density of communication networks was positively related to the age of nursing staff of the units. Multilevel analyses showed that job satisfaction differed significantly between individual staff members and units and was influenced by the number of nursing staff of the units. However, this relationship disappeared when density of communication networks was added to the model. Conclusions: Overall, communication and advice networks of nursing staff in long-term care are relatively dense. This fits with the high level of cooperation that is needed to provide good care to residents. Social networks are more dense in small units and are also shaped by characteristics of staff members. The results furthermore show that communication networks are important for staff's job satisfaction. (aut. ref.
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