83 research outputs found

    Potential climatic transitions with profound impact on Europe

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    We discuss potential transitions of six climatic subsystems with large-scale impact on Europe, sometimes denoted as tipping elements. These are the ice sheets on Greenland and West Antarctica, the Atlantic thermohaline circulation, Arctic sea ice, Alpine glaciers and northern hemisphere stratospheric ozone. Each system is represented by co-authors actively publishing in the corresponding field. For each subsystem we summarize the mechanism of a potential transition in a warmer climate along with its impact on Europe and assess the likelihood for such a transition based on published scientific literature. As a summary, the ‘tipping’ potential for each system is provided as a function of global mean temperature increase which required some subjective interpretation of scientific facts by the authors and should be considered as a snapshot of our current understanding. <br/

    Design of a multicentered randomized controlled trial on the clinical and cost effectiveness of schema therapy for personality disorders

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    <p>Abstract</p> <p>Background</p> <p>Despite international guidelines describing psychotherapy as first choice for people with personality disorders (PDs), well-designed research on the effectiveness and cost-effectiveness of psychotherapy for PD is scarce. Schema therapy (ST) is a specific form of psychological treatment that proved to be effective for borderline PD. Randomized controlled studies on the effectiveness of ST for other PDs are lacking. Another not yet tested new specialized treatment is Clarification Oriented Psychotherapy (COP). The aim of this project is to perform an effectiveness study as well as an economic evaluation study (cost effectiveness as well as cost-utility) comparing ST versus COP versus treatment as usual (TAU). In this study, we focus on avoidant, dependent, obsessive-compulsive, paranoid, histrionic and narcissistic PD.</p> <p>Methods/Design</p> <p>In a multicentered randomized controlled trial, ST, and COP as an extra experimental condition, are compared to TAU. Minimal 300 patients are recruited in 12 mental health institutes throughout the Netherlands, and receive an extensive screening prior to enrolment in the study. When eligible, they are randomly assigned to one of the intervention groups. An economic evaluation and a qualitative research study on patient and therapist perspectives on ST are embedded in this trial. Outcome assessments (both for clinical effectiveness and economic evaluation) take place at 6,12,18,24 and 36 months after start of treatment. Primary outcome is recovery from PD; secondary measures include general psychopathological complaints, social functioning and quality of life. Data for the cost-effectiveness and cost-utility analyses are collected by using a retrospective cost interview. Information on patient and therapist perspectives is gathered using in-depth interviews and focus groups, and focuses on possible helpful and impeding aspects of ST.</p> <p>Discussion</p> <p>This trial is the first to compare ST and COP head-to-head with TAU for people with a cluster C, paranoid, histrionic and/or narcissistic PD. By combining clinical effectiveness data with an economic evaluation and with direct information from primary stakeholders, this trial offers a complete and thorough view on ST as a contribution to the improvement of treatment for this PD patient group.</p> <p>Trial registration</p> <p>Netherlands Trial Register (NTR): <a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=566">NTR566</a></p

    Designing nanomaterials with desired mechanical properties by constraining the evolution of their grain shapes

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    Grain shapes are acknowledged to impact nanomaterials' overall properties. Research works on this issue include grain-elongation and grain-strain measurements and their impacts on nanomaterials' mechanical properties. This paper proposes a stochastic model for grain strain undergoing severe plastic deformation. Most models deal with equivalent radii assuming that nanomaterials' grains are spherical. These models neglect true grain shapes. This paper also proposes a theoretical approach of extending existing models by considering grain shape distribution during stochastic design and modelling of nanomaterials' constituent structures and mechanical properties. This is achieved by introducing grain 'form'. Example 'forms' for 2-D and 3-D grains are proposed. From the definitions of form, strain and Hall-Petch-Relationship to Reversed-Hall-Petch-Relationship, data obtained for nanomaterials' grain size and conventional materials' properties are sufficient for analysis. Proposed extended models are solved simultaneously and tested with grain growth data. It is shown that the nature of form evolution depends on form choice and dimensional space. Long-run results reveal that grain boundary migration process causes grains to become spherical, grain rotation coalescence makes them deviate away from becoming spherical and they initially deviate away from becoming spherical before converging into spherical ones due to the TOTAL process. Percentage deviations from spherical grains depend on dimensional space and form: 0% minimum and 100% maximum deviations were observed. It is shown that the plots for grain shape functions lie above the spherical (control) value of 1 in 2-D grains for all considered grain growth mechanisms. Some plots lie above the spherical value, and others approach the spherical value before deviating below it when dealing with 3-D grains. The physical interpretations of these variations are explained from elementary principles about the different grain growth mechanisms. It is observed that materials whose grains deviate further away from the spherical ones have more enhanced properties, while materials with spherical grains have lesser properties. It is observed that there exist critical states beyond which Hall-Petch Relationship changes to Reversed Hall-Petch Relationship. It can be concluded that if grain shapes in nanomaterials are constrained in the way they evolve, then nanomaterials with desired properties can be designed

    BISMUTH SEGREGATION IN Cu-Bi BICRYSTALS

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    The grain boundaries of randomly oriented Cu- Bi bicrystals containing about 300 wt ppm Bi were studied with a high-resolution scanning Auger microprobe. The non-planar interfaces, strongly facetted in many areas due to the Bi segregation, revealed a rather uniform Bi coverage despite a great variation in grain boundary structure. Particles concluded to be Bi were found on large areas of the intergranular fracture surfaces, apparently coexisting with the segregated layer of atomic bismuth. The Bi particles could be dissolved by heating the specimens to temperatures as low as 650°C and quenching

    Climate Variations

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