410 research outputs found

    Technical alignment

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    This essay discusses the importance of the areas of infrastructure and testing to help digital preservation services demonstrate reliability, transparency, and accountability. It encourages practitioners to build a strong culture in which transparency and collaborations between technical frameworks are valued highly. It also argues for devising and applying agreed-upon metrics that will enable the systematic analysis of preservation infrastructure. The essay begins by defining technical infrastructure and testing in the digital preservation context, provides case studies that exemplify both progress and challenges for technical alignment in both areas, and concludes with suggestions for achieving greater degrees of technical alignment going forward

    On the Construction of Common Size, Value and Momentum Factors in International Stock Markets: A Guide with Applications

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    Demand is growing for a better understanding of how assets are priced in countries outside of the U.S. While financial data are available for many firms world-wide, it is important to have a reliable and replicable method of constructing high-quality systematic risk factors from these data. This paper first documents that appropriately screened data from Thomson Reuters Datastream and Thomson Reuters Worldscope can be used to replicate closely not only U.S. market returns and the corresponding momentum risk factor (as existing work has suggested), but also the widely-used U.S. size and value risk factors. We then build novel pan-European and country-specific momentum, size, and value risk factors. By comparing our pan-European market returns and risk factors with their counterparts in the U.S., we find that they are astonishingly highly correlated. The factors we compute are made available to other researchers.Risk factors; value, size, momentum, international equity markets, asset pricing anomalies

    Socio-cultural norms of body size in Westerners and Polynesians affect heart rate variability and emotion during social interactions

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    The perception of body size and thus weight-related stigmatization vary between cultures. Both are stronger in Western than in Polynesian societies. Negative emotional experiences alter one’s behavioral, psychological, and physiological reactions in social interactions. This study compared affective and autonomic nervous system responses to social interactions in Germany and American Samoa, two societies with different body-size related norms. German (n = 55) and Samoan (n = 56) volunteers with and without obesity participated in a virtual ball-tossing game that comprised episodes of social inclusion and social exclusion. During the experiment, heart rate was measured and parasympathetic activity (i.e., high-frequency heart rate variability) was analyzed. We found differences in both emotional experience and autonomic cardio-regulation between the two cultures: during social inclusion, Germans but not Samoans showed increased parasympathetic activity. In Germans with obesity, this increase was related to a more negative body image (comprising high rates of weight-related teasing). During social exclusion, Samoans showed parasympathetic withdrawal regardless of obesity status, while Germans with obesity showed a stronger increase in parasympathetic activity than lean Germans. Furthermore, we found fewer obesity-related differences in emotional arousal after social exclusion in Samoans as compared to Germans. Investigating the interplay of socio-cultural, psychological, and biological aspects, our results suggest influences of body size-related socio-cultural norms on parasympathetic cardio-regulation and negative emotions during social interactions

    DNA methylation-based profiling of bone and soft tissue tumours: a validation study of the 'DKFZ Sarcoma Classifier'

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    Diagnosing bone and soft tissue neoplasms remains challenging because of the large number of subtypes, many of which lack diagnostic biomarkers. DNA methylation profiles have proven to be a reliable basis for the classification of brain tumours and, following this success, a DNA methylation-based sarcoma classification tool from the Deutsches Krebsforschungszentrum (DKFZ) in Heidelberg has been developed. In this study, we assessed the performance of their classifier on DNA methylation profiles of an independent data set of 986 bone and soft tissue tumours and controls. We found that the 'DKFZ Sarcoma Classifier' was able to produce a diagnostic prediction for 55% of the 986 samples, with 83% of these predictions concordant with the histological diagnosis. On limiting the validation to the 820 cases with histological diagnoses for which the DKFZ Classifier was trained, 61% of cases received a prediction, and the histological diagnosis was concordant with the predicted methylation class in 88% of these cases, findings comparable to those reported in the DKFZ Classifier paper. The classifier performed best when diagnosing mesenchymal chondrosarcomas (CHSs, 88% sensitivity), chordomas (85% sensitivity), and fibrous dysplasia (83% sensitivity). Amongst the subtypes least often classified correctly were clear cell CHSs (14% sensitivity), malignant peripheral nerve sheath tumours (27% sensitivity), and pleomorphic liposarcomas (29% sensitivity). The classifier predictions resulted in revision of the histological diagnosis in six of our cases. We observed that, although a higher tumour purity resulted in a greater likelihood of a prediction being made, it did not correlate with classifier accuracy. Our results show that the DKFZ Classifier represents a powerful research tool for exploring the pathogenesis of sarcoma; with refinement, it has the potential to be a valuable diagnostic tool

    Ownership and control in a competitive industry

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    We study a differentiated product market in which an investor initially owns a controlling stake in one of two competing firms and may acquire a non-controlling or a controlling stake in a competitor, either directly using her own assets, or indirectly via the controlled firm. While industry profits are maximized within a symmetric two product monopoly, the investor attains this only in exceptional cases. Instead, she sometimes acquires a noncontrolling stake. Or she invests asymmetrically rather than pursuing a full takeover if she acquires a controlling one. Generally, she invests indirectly if she only wants to affect the product market outcome, and directly if acquiring shares is profitable per se. --differentiated products,separation of ownership and control,private benefits of control

    Comparative Functional Analysis of the Caenorhabditis elegans and Drosophila melanogaster Proteomes

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    The nematode Caenorhabditis elegans is a popular model system in genetics, not least because a majority of human disease genes are conserved in C. elegans. To generate a comprehensive inventory of its expressed proteome, we performed extensive shotgun proteomics and identified more than half of all predicted C. elegans proteins. This allowed us to confirm and extend genome annotations, characterize the role of operons in C. elegans, and semiquantitatively infer abundance levels for thousands of proteins. Furthermore, for the first time to our knowledge, we were able to compare two animal proteomes (C. elegans and Drosophila melanogaster). We found that the abundances of orthologous proteins in metazoans correlate remarkably well, better than protein abundance versus transcript abundance within each organism or transcript abundances across organisms; this suggests that changes in transcript abundance may have been partially offset during evolution by opposing changes in protein abundance
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