Background: Different surgical approaches for total hip arthroplasty (THA) exist, without predisposition when it comes to dislocation risk. The direct anterior approach (DAA) is thought to have reduced risk since soft tissue trauma is minimalized. Therefore, we assessed the dislocation risk for different surgical approaches, and the relative dislocation risk of DAA compared to other approaches. Methods: Six electronic databases were systematically searched for prospective studies reporting dislocation following THA. Proportion meta-analyses were performed to assess the dislocation rate for subgroups of the surgical approach. Meta-analysis for binary outcomes was performed to determine the relative risk of dislocation for the DAA compared to other approaches. Results: Eleven studies with 2025 patients were included (mean age 64.6 years, 44% male, mean follow-up 10.5 months), of which four studies were also used in the risk ratio meta-analysis. Overall dislocation rate was 0.79% (95% CI 0.37–1.69). Subgroup analyses showed that most dislocations occurred in the posterior approaches group (1.38%), however non-significant. Furthermore, the DAA emerged with a non-significant lower risk of dislocation (RR 0.37, 95% CI 0.05–2.46) compared to other surgical approaches. Conclusion: Current literature shows non-significant predisposition for a surgical approach to THA regarding dislocation risk. To what extent patient characteristics influence the risk of dislocation could not be determined. Future research should focus on this, as well as on the influence of a surgeon's experience with a specific approach.
Background: Falls in stroke survivors can lead to serious injuries and medical costs. Fall risk in older adults can be predicted based on gait characteristics measured in daily life. Given the different gait patterns that stroke survivors exhibit it is unclear whether a similar fall-prediction model could be used in this group. Therefore the main purpose of this study was to examine whether fall-prediction models that have been used in older adults can also be used in a population of stroke survivors, or if modifications are needed, either in the cut-off values of such models, or in the gait characteristics of interest. Methods: This study investigated gait characteristics by assessing accelerations of the lower back measured during seven consecutive days in 31 non fall-prone stroke survivors, 25 fall-prone stroke survivors, 20 neurologically intact fall-prone older adults and 30 non fall-prone older adults. We created a binary logistic regression model to assess the ability of predicting falls for each gait characteristic. We included health status and the interaction between health status (stroke survivors versus older adults) and gait characteristic in the model. Results: We found four significant interactions between gait characteristics and health status. Furthermore we found another four gait characteristics that had similar predictive capacity in both stroke survivors and older adults. Conclusion: The interactions between gait characteristics and health status indicate that gait characteristics are differently associated with fall history between stroke survivors and older adults. Thus specific models are needed to predict fall risk in stroke survivors.
In this paper validity and compatibility of the SAM and KLD screening instruments are the central themes. A screening instrument can be called valid if it identifies performance that is important to society. A screening instrument is called compatible if these instruments can be used interchangeably. Validity The outcome of the content-analysis approach suggest that there is clearly not a perfect match between the SAM and KLD instruments and the CSAF, indicating that the SAM and KLD screening instruments taken the CSAF as the standard, cannot be called valid measures of corporate sustainability performance. However, as discussed earlier, assessing validity is not a binary phenomenon. A simple ‘yes’ or ‘no’ will not do. To make things more complicated, the validity of a measure also depends on the aggregation level under observation. It makes a big difference if validity is assessed at a high (i.e. Dimension) or low aggregation (i.e. Sustainability Item) level . At the highest level there is a perfect match with the CSAF, indicating that both screening instruments are valid measures of corporate sustainability performance. At the lowest level the situation is quite different. Here we see that overlap is relatively poor. Besides, the weight distributions of the SAM and KLD instruments and the CSAF are also largely dissimilar. When we break the validity discussion down to the Dimension level, we can see that overlap between the SAM and KLD instruments is also relatively poor, although the SAM instrument is slightly more attuned to the CSAF than the KLD instrument. This most notably applies to the Governance Dimension. The SAM instrument scores relatively poor on environmental issues. This is due to the fact that we analyzed the generic (i.e. non-industry specific) screening instrument. SAM typically addresses environmental issues in industry specific supplements. CompatibilityThe second question in this study concerns the compatibility of the SAM and KLD screening instruments. Or more accurately phrased: the extent to which these rating schemes are compatible. If we would consider compatibility assessment of screening instruments as a binary phenomenon, then we should conclude that the SAM and KLD instruments are not compatible.However, just like validity, assessing the compatibility of screening instruments is not a binary phenomenon. The extent to which the rating schemes of the two SRAs are compatible relates to the aggregation level. At the highest aggregation ( or Dimension) level the screening instruments are perfectly compatible. Both instruments cover governance, social, environmental and economic issues. At the lowest (or Sustainability Item) level the situation is quite different. At this level compatibility of both instruments is poor. Overlap is poor and the weight distributions are hardly correlated. Obviously both instruments are reflect different interpretations of corporate sustainability performance. Compatibility is highest for the Social Dimension. For the Governance, Environment and Economic Dimension compatibility is very poor. The overall conclusion should therefore be that that compatibility of the SAM and KLD screening instruments is (very) poor and that for this reason these instruments cannot
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The project aim is to improve collusion resistance of real-world content delivery systems. The research will address the following topics: • Dynamic tracing. Improve the Laarhoven et al. dynamic tracing constructions [1,2] [A11,A19]. Modify the tally based decoder [A1,A3] to make use of dynamic side information. • Defense against multi-channel attacks. Colluders can easily spread the usage of their content access keys over multiple channels, thus making tracing more difficult. These attack scenarios have hardly been studied. Our aim is to reach the same level of understanding as in the single-channel case, i.e. to know the location of the saddlepoint and to derive good accusation scores. Preferably we want to tackle multi-channel dynamic tracing. • Watermarking layer. The watermarking layer (how to embed secret information into content) and the coding layer (what symbols to embed) are mostly treated independently. By using soft decoding techniques and exploiting the “nuts and bolts” of the embedding technique as an extra engineering degree of freedom, one should be able to improve collusion resistance. • Machine Learning. Finding a score function against unknown attacks is difficult. For non-binary decisions there exists no optimal procedure like Neyman-Pearson scoring. We want to investigate if machine learning can yield a reliable way to classify users as attacker or innocent. • Attacker cost/benefit analysis. For the various use cases (static versus dynamic, single-channel versus multi-channel) we will devise economic models and use these to determine the range of operational parameters where the attackers have a financial benefit. For the first three topics we have a fairly accurate idea how they can be achieved, based on work done in the CREST project, which was headed by the main applicant. Neural Networks (NNs) have enjoyed great success in recognizing patterns, particularly Convolutional NNs in image recognition. Recurrent NNs ("LSTM networks") are successfully applied in translation tasks. We plan to combine these two approaches, inspired by traditional score functions, to study whether they can lead to improved tracing. An often-overlooked reality is that large-scale piracy runs as a for-profit business. Thus countermeasures need not be perfect, as long as they increase the attack cost enough to make piracy unattractive. In the field of collusion resistance, this cost analysis has never been performed yet; even a simple model will be valuable to understand which countermeasures are effective.
