A physics-based statistical model for human gait analysis

Physics-based modeling is a powerful tool for human gait analysis and synthesis. Unfortunately, its application suffers from high computational cost regarding the solution of optimization problems and uncertainty in the choice of a suitable objective energy function and model parametrization. Our approach circumvents these problems by learning model parameters based on a training set of walking sequences. We propose a combined representation of motion parameters and physical parameters to infer missing data without the need for tedious optimization. Both a κ-nearest-neighbour approach and asymmetrical principal component analysis are used to deduce ground reaction forces and joint torques directly from an input motion. We evaluate our methods by comparing with an iterative optimization-based method and demonstrate the robustness of our algorithm by reducing the input joint information. With decreasing input information the combined statistical model regression increasingly outperforms the iterative optimization-based method

Circulating Lysophosphatidylcholines Are Markers of a Metabolically Benign Nonalcoholic Fatty Liver

OBJECTIVENonalcoholic fatty liver (NAFL) is thought to contribute to insulin resistance and its metabolic complications. However, some individuals with NAFL remain insulin sensitive. Mechanisms involved in the susceptibility to develop insulin resistance in humans with NAFL are largely unknown. We investigated circulating markers and mechanisms of a metabolically benign and malignant NAFL by applying a metabolomic approach.RESEARCH DESIGN AND METHODSA total of 265 metabolites were analyzed before and after a 9-month lifestyle intervention in plasma from 20 insulin-sensitive and 20 insulin-resistant subjects with NAFL. The relevant plasma metabolites were then tested for relationships with insulin sensitivity in 17 subjects without NAFL and in plasma from 29 subjects with liver tissue samples.RESULTSThe best separation of the insulin-sensitive from the insulin-resistant NAFL group was achieved by a metabolite pattern including the branched-chain amino acids leucine and isoleucine, ornithine, the acylcarnitines C3:0-, C16:0-, and C18:0-carnitine, and lysophosphatidylcholine (lyso-PC) C16:0 (area under the ROC curve, 0.77 [P = 0.00023] at baseline and 0.80 [P = 0.000019] at follow-up). Among the individual metabolites, predominantly higher levels of lyso-PC C16:0, both at baseline (P = 0.0039) and at follow-up (P = 0.001), were found in the insulin-sensitive compared with the insulin-resistant subjects. In the non-NAFL groups, no differences in lyso-PC C16:0 levels were found between the insulin-sensitive and insulin-resistant subjects, and these relationships were replicated in plasma from subjects with liver tissue samples.CONCLUSIONSFrom a plasma metabolomic pattern, particularly lyso-PCs are able to separate metabolically benign from malignant NAFL in humans and may highlight important pathways in the pathogenesis of fatty liver-induced insulin resistance

Institutional factors and opportunities for adapting European forest management to climate change

Despite the fact that the institutional environment is acknowledged to influence the implementation of regional adaptations of forest management to climate change, there are few empirical studies addressing the institutional factors and opportunities of adaptation. Using Ostrom’s institutional analysis and development framework, we aimed to identify : (1) the critical and distinctive characteristics of the forest resource and institutional context that may determine how climate change-adaptive forest management measures are implemented and (2) the opportunities for implementing the planned adaptation measures. The analysis is performed on ten European case study regions which differed in many resource-dependent factors, policy arena factors and incentives for changes. The main factors influencing the adaptation are the ownership pattern, the level of policy formation and the nature of forest goods and services. Opportunities for adaptation are driven by the openness of the forest management planning processes to the stakeholders participation, the degree to which business as usual management is projected to be non-satisfactory in the future, and by the number and nature of obstacles to adaptation. Promoting local self-governance mechanisms and the participation of the external stakeholders in forest management planning or in the regional forest or climate change policy adaptation may be a way of overcoming path dependency, behavioural obstacles and potential policy failures in implementing adaptation. The study argues that both climate change belief systems and political participation are important to explain adaptation to climate change when multiple decision-making levels are at stake