Discontinuous Galerkin finite element approximation of quasilinear elliptic boundary value problems II: Strongly monotone quasi-Newtonian flows

In this article, we develop the a priori and a posteriori error analysis of hp-version interior penalty discontinuous Galerkin finite element methods for strongly monotone quasi-Newtonian fluid flows in a bounded Lipschitz domain Ω ⊂ ℝd, d = 2, 3. In the latter case, computable upper and lower bounds on the error are derived in terms of a natural energy norm, which are explicit in the local mesh size and local polynomial degree of the approximating finite element method. A series of numerical experiments illustrate the performance of the proposed a posteriori error indicators within an automatic hp-adaptive refinement algorithm.

Computational Comparison of Continuous and Discontinuous Galerkin Time-Stepping Methods for Nonlinear Initial Value Problems

This article centers on the computational performance of the continuous and discontinuous Galerkin time stepping schemes for general first-order initial value problems in R n , with continuous nonlinearities. We briefly review a recent existence result for discrete solutions from [6], and provide a numerical comparison of the two time discretization methods.

hp-dGFEM for Second-Order Elliptic Problems in Plyhedra I: Stability and Quasioptimality on Geometric Meshes

We introduce and analyze hp-version discontinuous Galerkin (dG) finite element methods for the numerical approximation of linear second-order elliptic boundary-value problems in three-dimensional polyhedral domains. To resolve possible corner-, edge- and corner-edge singularities, we consider hexahedral meshes that are geometrically and anisotropically refined toward the corresponding neighborhoods. Similarly, the local polynomial degrees are increased linearly and possibly anisotropically away from singularities. We design interior penalty hp-dG methods and prove that they are well-defined for problems with singular solutions and stable under the proposed hp-refinements. We establish (abstract) error bounds that will allow us to prove exponential rates of convergence in the second part of this work.

hp-dGFEM for Second-Order Elliptic Problems in Plyhedra II: Exponential Convergence

The goal of this paper is to establish exponential convergence of $hp$-version interior penalty (IP) discontinuous Galerkin (dG) finite element methods for the numerical approximation of linear second-order elliptic boundary-value problems with homogeneous Dirichlet boundary conditions and piecewise analytic data in three-dimensional polyhedral domains. More precisely, we shall analyze the convergence of the $hp$-IP dG methods considered in [D. Schötzau, C. Schwab, T. P. Wihler, SIAM J. Numer. Anal., 51 (2013), pp. 1610--1633] based on axiparallel $\sigma$-geometric anisotropic meshes and $\bm{s}$-linear anisotropic polynomial degree distributions.

A boundary value problem approach to too-short arc optical track association

Given a short-arc optical observation with estimated angle-rates, the admissible region is a compact region in the range / range-rate space defined such that all likely and relevant orbits are contained within it. An alternative boundary value problem formulation has recently been proposed where range / range hypotheses are generated with two angle measurements from two tracks as input. In this paper, angle-rate information is reintroduced as a means to eliminate hypotheses by bounding their constants of motion before a more computationally costly Lambert solver or differential correction algorithm is run.

Short-arc tracklet association for geostationary objects

Measurement association and initial orbit determination is a fundamental task when building up a database of space objects. This paper proposes an efficient and robust method to determine the orbit using the available information of two tracklets, i.e. their line-of-sights and their derivatives. The approach works with a boundary-value formulation to represent hypothesized orbital states and uses an optimization scheme to find the best fitting orbits. The method is assessed and compared to an initial-value formulation using a measurement set taken by the Zimmerwald Small Aperture Robotic Telescope of the Astronomical Institute at the University of Bern. False associations of closely spaced objects on similar orbits cannot be completely eliminated due to the short duration of the measurement arcs. However, the presented approach uses the available information optimally and the overall association performance and robustness is very promising. The boundary-value optimization takes only around 2% of computational time when compared to optimization approaches using an initial-value formulation. The full potential of the method in terms of run-time is additionally illustrated by comparing it to other published association methods.

Decision-Making Processes in Voluntary Football Clubs in Relation to External Counselling

Introduction Recruiting and retaining volunteers who are prepared to make a long-term commitment is a major problem for Swiss sports clubs. With the inclusion of external counselling for the change and systematisation of volunteer management, sports clubs have a possibility to develop and defuse problems in spite of existing barriers and gaps in knowledge. To what extent is external counselling for personnel problems effective? It is often observed that standardised counselling inputs lead to varying consequences for sports clubs. It can be assumed that external impulses are interpreted and transformed differently into the workings of the club. However, this cannot be solely attributed to the situational or structural conditions of the clubs. It is also important to consider the underlying decision-making processes of a club. According to Luhmann’s organisational sociological considerations (2000), organisations (sports clubs) have to be viewed as social systems consisting of (communicated) decisions. This means that organisations are continually reproduced by decision-making processes. All other (observable) factors such as an organisation’s goals, recruiting strategies, support schemes for volunteers etc., have to be seen as an outcome of the operation of prior organisational decisions. Therefore: How do decision-making processes in sports clubs work in the context of the implementation of external counselling? Theoretical Framework An examination of the actual situation in sports clubs shows that decisions frequently appear to be shaped by inconsistency, unexpected outcomes, and randomness (Amis & Slack, 2003). Therefore, it must be emphasised that these decisions cannot be analysed according to any rational decision-making model. Their specific structural characteristics only permit a limited degree of rationality – bounded rationality. Non-profit organisations in particular are shaped by a specific mode of decisionmaking that Cohen, March, and Olsen (1972) have called the “garbage can model”. As sport clubs can also be conceived as “organised anarchies”, this model seems to offer an appropriate approach to understanding their practices and analysing their decision-making processes. The key concept in the garbage can model is the assumption that decision-making processes in organisations consist of four “streams”: (a) problems, (b) actors, (c) decision-making opportunities, and (d) solutions. Method Before presenting the method of the analysis of the decision-making processes in sports clubs, the external counselling will be described. The basis of the counselling is generated by a sports clubs’ capability to change. Due to the specific structural characteristics and organisational principles, change processes in sports clubs often merge with barriers and restrictions. These need to be considered when developing counselling guidelines for a successful planning and realisation of change processes. Furthermore, important aspects of personnel management in sports clubs and especially volunteer management must be implied in order to elaborate key elements for the counselling to recruit new volunteers (e.g., approach, expectations). A counselling of four system-counselling workshops was conceptualised by considering these specific characteristics. The decision-making processes in the sports clubs were analysed during the counselling and the implementation process. A case study is designed with the appropriate methodological approach for such explorative research. The approach adopted for these single case analyses was oriented toward the research program of behavioural decision-making theory (garbage can model). This posits that in-depth insights into organisational decision-making processes can only be gained through relevant case studies of existing organisational situations (Skille, 2013). Before, during and after the intervention, questionnaires and guided interviews were conducted with the project teams of the twelve par-ticipating football clubs to assess the different components of the “streams” in the context of external counselling. These interviews have been analysed using content analysis following guidelines as for-mulated by Mayring (2010). Results The findings show that decision-making processes in football clubs occur differently in the context of external counselling. Different initial positions and problems are the triggers for these decision-making processes. Furthermore, the implementation of the solutions and the external counselling is highly dependent on the commitment of certain people as central players within the decision-mak-ing process. The importance of these relationships is confirmed by previous findings in regard to decision-making and change processes in sports clubs. The decision-making processes in sports clubs can be theoretically analysed using behavioural decision-making theory and the “garbage can model”. Bounded rationality characterises all “streams” of the decision-making processes. Moreo-ver, the decision-making process of the football clubs can be well illustrated in the framework, and the interplay of the different dimensions illustrates the different decision-making practices within the football clubs. References Amis, J., & Slack, T. (2003). Analysing sports organisations: Theory and practice. In B. Houlihan (Eds.), Sport & Society (pp. 201–217). London, England: Sage. Cohen, M.D., March, J.G., & Olsen, J.P. (1972). A garbage can model of organisational choice. Ad-ministrative Science Quarterly, 17, 1-25. Luhmann, N. (2000). Organisation und Entscheidung. Opladen: Westdeutscher Verlag. Mayring, P. (2010). Qualitative Inhaltsanalyse. Grundlagen und Techniken. Weinheim: Beltz. Skille, E. Å. (2013). Case study research in sport management: A reflection upon the theory of science and an empirical example. In S. Söderman & H. Dolles (Eds.), Handbook of research on sport and business (pp. 161–175). Cheltenham, England: Edward Elgar.

Predictive value of the Acute Low Back Pain Screening Questionnaire and the Örebro Musculoskeletal Pain Screening Questionnaire for persisting problems

A small proportion of individuals with non-specific low back pain (NSLBP) develop persistent problems. Up to 80% of the total costs for NSLBP are owing to chronic NSLBP. Psychosocial factors have been described to be important in the transition from acute to chronic NSLBP. Guidelines recommend the use of the Acute Low Back Pain Screening Questionnaire (ALBPSQ) and the Örebro Musculoskeletal Pain Screening Questionnaire (ÖMPSQ) to identify individuals at risk of developing persistent problems, such as long-term absence of work, persistent restriction in function or persistent pain. These instruments can be used with a cutoff value, where patients with values above the threshold are further assessed with a more comprehensive examination.

Prognostic value of PCSK9 levels in patients with acute coronary syndromes.

AIMS Proprotein convertase subtilisin kexin 9 (PCSK9) is an emerging target for the treatment of hypercholesterolaemia, but the clinical utility of PCSK9 levels to guide treatment is unknown. We aimed to prospectively assess the prognostic value of plasma PCSK9 levels in patients with acute coronary syndromes (ACS). METHODS AND RESULTS Plasma PCSK9 levels were measured in 2030 ACS patients undergoing coronary angiography in a Swiss prospective cohort. At 1 year, the association between PCSK9 tertiles and all-cause death was assessed adjusting for the Global Registry of Acute Coronary Events (GRACE) variables, as well as the achievement of LDL cholesterol targets of <1.8 mmol/L. Patients with higher PCSK9 levels at angiography were more likely to have clinical familial hypercholesterolaemia (rate ratio, RR 1.21, 95% confidence interval, CI 1.09-1.53), be treated with lipid-lowering therapy (RR 1.46, 95% CI 1.30-1.63), present with longer time interval of chest pain (RR 1.29, 95% CI 1.09-1.53) and higher C-reactive protein levels (RR 1.22, 95% CI 1.16-1.30). PCSK9 increased 12-24 h after ACS (374 ± 149 vs. 323 ± 134 ng/mL, P < 0.001). At 1 year follow-up, HRs for upper vs. lower PCSK9-level tertiles were 1.13 (95% CI 0.69-1.85) for all-cause death and remained similar after adjustment for the GRACE score. Patients with higher PCSK9 levels were less likely to reach the recommended LDL cholesterol targets (RR 0.81, 95% CI 0.66-0.99). CONCLUSION In ACS patients, high initial PCSK9 plasma levels were associated with inflammation in the acute phase and hypercholesterolaemia, but did not predict mortality at 1 year.

Prognostic value of the Geneva prediction rule in patients in whom pulmonary embolism is ruled out

The prognosis of patients in whom pulmonary embolism (PE) is suspected but ruled out is poorly understood. We evaluated whether the initial assessment of clinical probability of PE could help to predict the prognosis for these patients.

Value and pitfalls of neurophysiological monitoring in thoracic and thoracoabdominal aortic replacement and endovascular repair

The aim of our study was to analyze the neurophysiological monitoring method with regard to its potential problems during thoracic and thoracoabdominal aortic open or endovascular repair. Furthermore, preventive strategies to the main pitfalls with this method were developed.

Can molecular markers stratify the diagnostic value of high-grade prostatic intraepithelial neoplasia?

The diagnostic performance of isolated high-grade prostatic intraepithelial neoplasia in prostatic biopsies has recently been questioned, and molecular analysis of high-grade prostatic intraepithelial neoplasia has been proposed for improved prediction of prostate cancer. Here, we retrospectively studied the value of isolated high-grade prostatic intraepithelial neoplasia and the immunohistochemical markers ?-methylacyl coenzyme A racemase, Bcl-2, annexin II, and Ki-67 for better risk stratification of high-grade prostatic intraepithelial neoplasia in our local Swiss population. From an initial 165 diagnoses of isolated high-grade prostatic intraepithelial neoplasia, we refuted 61 (37%) after consensus expert review. We used 30 reviewed high-grade prostatic intraepithelial neoplasia cases with simultaneous biopsy prostate cancer as positive controls. Rebiopsies were performed in 66 patients with isolated high-grade prostatic intraepithelial neoplasia, and the median time interval between initial and repeat biopsy was 3 months. Twenty (30%) of the rebiopsies were positive for prostate cancer, and 10 (15%) showed persistent isolated high-grade prostatic intraepithelial neoplasia. Another 2 (3%) of the 66 patients were diagnosed with prostate cancer in a second rebiopsy. Mean prostate-specific antigen serum levels did not significantly differ between the 22 patients with prostate cancer and the 44 without prostate cancer in rebiopsies, and the 30 positive control patients, respectively (median values, 8.1, 7.7, and 8.8 ng/mL). None of the immunohistochemical markers, including ?-methylacyl coenzyme A racemase, Bcl-2, annexin II, and Ki-67, revealed a statistically significant association with the risk of prostate cancer in repeat biopsies. Taken together, the 33% risk of being diagnosed with prostate cancer after a diagnosis of high-grade prostatic intraepithelial neoplasia justifies rebiopsy, at least in our not systematically prostate-specific antigen-screened population. There is not enough evidence that immunohistochemical markers can reproducibly stratify the risk of prostate cancer after a diagnosis of isolated high-grade prostatic intraepithelial neoplasia.