Nachbauproblematik bei Apfelbäumen

Bei wiederholtem Anbau von Obstbäumen am gleichen Standort wird häufig ein verminderter Wuchs und ein reduzierter Ertrag beobachtet. Dieses Phänomen wird als Nachbauproblem oder Bodenmüdigkeit bezeichne

Chlamydia control activities in Europe: cross-sectional survey

Background: Chlamydia is the most commonly reported bacterial sexually transmitted infection in Europe. The objective of the Screening for Chlamydia in Europe (SCREen) project was to describe current and planned chlamydia control activities in Europe. Methods: The authors sent a questionnaire asking about different aspects of chlamydia epidemiology and control to public health and clinical experts in each country in 2007. The principles of sexually transmitted infection control were used to develop a typology comprising five categories of chlamydia control activities. Each country was assigned to a category, based on responses to the questionnaire. Results: Experts in 29 of 33 (88%) invited countries responded. Thirteen of 29 countries (45%) had no current chlamydia control activities. Six countries in this group stated that there were plans to introduce chlamydia screening programmes. There were five countries (17%) with case management guidelines only. Three countries (10%) also recommended case finding amongst partners of diagnosed chlamydia cases or people with another sexually transmitted infection. Six countries (21%) further specified groups of asymptomatic people eligible for opportunistic chlamydia testing. Two countries (7%) reported a chlamydia screening programme. There was no consistent association between the per capita gross domestic product of a country and the intensity of chlamydia control activities (P = 0.816). Conclusion: A newly developed classification system allowed the breadth of ongoing national chlamydia control activities to be described and categorized. Chlamydia control strategies should ensure that clinical guidelines to optimize chlamydia diagnosis and case management have been implemented before considering the appropriateness of screening programmes

Presenting a comprehensive multi-scale evaluation framework for participatory modelling programs: a scoping review

INTRODUCTION: Systems modelling and simulation can improve understanding of complex systems to support decision making, better managing system challenges. Advances in technology have facilitated accessibility of modelling by diverse stakeholders, allowing them to engage with and contribute to the development of systems models (participatory modelling). However, despite its increasing applications across a range of disciplines, there is a growing need to improve evaluation efforts to effectively report on the quality, importance, and value of participatory modelling. This paper aims to identify and assess evaluation frameworks, criteria, and/or processes, as well as to synthesize the findings into a comprehensive multi-scale framework for participatory modelling programs. MATERIALS AND METHODS: A scoping review approach was utilized, which involved a systematic literature search via Scopus in consultation with experts to identify and appraise records that described an evaluation framework, criteria, and/or process in the context of participatory modelling. This scoping review is registered with the Open Science Framework. RESULTS: The review identified 11 studies, which varied in evaluation purposes, terminologies, levels of examination, and time points. The review of studies highlighted areas of overlap and opportunities for further development, which prompted the development of a comprehensive multi-scale evaluation framework to assess participatory modelling programs across disciplines and systems modelling methods. The framework consists of four categories (Feasibility, Value, Change/Action, Sustainability) with 30 evaluation criteria, broken down across project-, individual-, group- and system-level impacts. DISCUSSION & CONCLUSION: The presented novel framework brings together a significant knowledge base into a flexible, cross-sectoral evaluation effort that considers the whole participatory modelling process. Developed through the rigorous synthesis of multidisciplinary expertise from existing studies, the application of the framework can provide the opportunity to understand practical future implications such as which aspects are particularly important for policy decisions, community learning, and the ongoing improvement of participatory modelling methods

Dynamic behaviour analysis of an english-bond masonry prototype using a homogenized-based discrete FE model

Full Finite Element strategies (the so called micro- and macro- models) are still nowadays the most used ones for the study of large masonry structures. However, macro-modelling still lacks accuracy at a meso-scale in terms of damage localization. On the other hand, micro-models are rather computational demanding and require a cumbersome modelling stage. Thus, homogenization-based frameworks give considerable advantages. Moreover, the study of English bond masonry appears to be disregarded in comparison to the running bond one. On this behalf, a two-step procedure based on homogenization theory is herein presented for the dynamic study of English-bond masonry structures. The presented homogenization approach uses two models at a micro-scale: (i) a plane-stress FE discretization within the concepts of Kirchhoff-Love plate theory; and (ii) a three-dimensional micro-model accounting with the mortar joint discontinuity existent at the thickness direction. Bricks are meshed with elastic elements with linear interpolation and joints are reduced to interfaces which obey to the nonlinear behaviour described by the so-called combined cracking-shearing-crushing model. The procedure allows obtaining homogenized bending moment/torque curvature relationships to be used at a structural level within a FE discrete model implemented in a commercial code. The model relies in rigid quadrilateral elements interconnected by homogenized bending/torque nonlinear springs. The framework is used to study the dynamic behaviour of an English-bond masonry wall benchmark. A macroscopic strategy is also considered to enrich the study. The numerical results are compared with the experimental data and a good agreement has been found.FCT (Portuguese Foundation for Science and Technology), within ISISE, scholarship SFRH/BD/95086/2013. This work was also partly financed by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-00763

A Finite Element Computation of the Gravitational Radiation emitted by a Point-like object orbiting a Non-rotating Black Hole

The description of extreme-mass-ratio binary systems in the inspiral phase is a challenging problem in gravitational wave physics with significant relevance for the space interferometer LISA. The main difficulty lies in the evaluation of the effects of the small body's gravitational field on itself. To that end, an accurate computation of the perturbations produced by the small body with respect the background geometry of the large object, a massive black hole, is required. In this paper we present a new computational approach based on Finite Element Methods to solve the master equations describing perturbations of non-rotating black holes due to an orbiting point-like object. The numerical computations are carried out in the time domain by using evolution algorithms for wave-type equations. We show the accuracy of the method by comparing our calculations with previous results in the literature. Finally, we discuss the relevance of this method for achieving accurate descriptions of extreme-mass-ratio binaries.Comment: RevTeX 4. 18 pages, 8 figure

Role of electromagnetically induced transparency in resonant four-wave-mixing schemes.

Published versio

Chlamydia control activities in Europe: cross-sectional survey

Background: Chlamydia is the most commonly reported bacterial sexually transmitted infection in Europe. The objective of the Screening for Chlamydia in Europe (SCREen) project was to describe current and planned chlamydia control activities in Europe. Methods: The authors sent a questionnaire asking about different aspects of chlamydia epidemiology and control to public health and clinical experts in each country in 2007. The principles of sexually transmitted infection control were used to develop a typology comprising five categories of chlamydia control activities. Each country was assigned to a category, based on responses to the questionnaire. Results: Experts in 29 of 33 (88%) invited countries responded. Thirteen of 29 countries (45%) had no current chlamydia control activities. Six countries in this group stated that there were plans to introduce chlamydia screening programmes. There were five countries (17%) with case management guidelines only. Three countries (10%) also recommended case finding amongst partners of diagnosed chlamydia cases or people with another sexually transmitted infection. Six countries (21%) further specified groups of asymptomatic people eligible for opportunistic chlamydia testing. Two countries (7%) reported a chlamydia screening programme. There was no consistent association between the per capita gross domestic product of a country and the intensity of chlamydia control activities (P = 0.816). Conclusion: A newly developed classification system allowed the breadth of ongoing national chlamydia control activities to be described and categorized. Chlamydia control strategies should ensure that clinical guidelines to optimize chlamydia diagnosis and case management have been implemented before considering the appropriateness of screening programme

Interaction effects at the magnetic-field induced metal-insulator transition in Si/SiGe superlattices

A metal-insulator transition was induced by in-plane magnetic fields up to 27 T in homogeneously Sb-doped Si/SiGe superlattice structures. The localisation is not observed for perpendicular magnetic fields. A comparison with magnetoconductivity investigations in the weakly localised regime shows that the delocalising effect originates from the interaction-induced spin-triplet term in the particle-hole diffusion channel. It is expected that this term, possibly together with the singlet particle-particle contribution, is of general importance in disordered n-type Si bulk and heterostructures.Comment: 5 pages, 3 figures, Solid State Communications, in prin