242 research outputs found

    Our Collective Tensions:Paradox Research Community’s Response to COVID-19

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    In this commentary on three articles from dozens of paradox theory scholars on paradox approaches to examining the COVID-19 pandemic and how the COVID-19 pandemic informs paradox theory, the authors involved in coordinating the collection of three papers discuss the process of bringing together scholars from around the world to discuss the pandemic. Four other preeminent paradox theorists offer additional commentaries on the papers in this Collection.</p

    The Mass of the Black Hole in the Seyfert 1 Galaxy NGC 4593 from Reverberation Mapping

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    We present new observations leading to an improved black hole mass estimate for the Seyfert 1 galaxy NGC 4593 as part of a reverberation-mapping campaign conducted at the MDM Observatory. Cross-correlation analysis of the H_beta emission-line light curve with the optical continuum light curve reveals an emission-line time delay of 3.73 (+-0.75) days. By combining this time delay with the H_beta line width, we derive a central black hole mass of M_BH = 9.8(+-2.1)x10^6 M_sun, an improvement in precision of a factor of several over past results.Comment: 22 pages, 3 tables, 5 figures, accepted for publication in Ap

    What Drives Home Bias? Evidence from Fund Managers' Views

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    A survey of fund managers reveals home bias for these sophisticated investors in an unrestricted setting. Proximity, perceived informational advantage and higher expected returns are confirmed as accompanying factors. In addition, the home bias of equity managers is also related to institutional, informational and behavioral characteristics. The perceived informational advantage does not seem to be valid. Multivariate analyses indicate that home bias is mainly related to relative return optimism, non-fundamental information and peculiar behavior towards risk. We interpret these as characteristics of less than fully rational behavior. It is consistently found that this pattern does not apply to bond managers.Eine Befragung von Fondsmanagern offenbart die Heimatverzerrung (sog. Home Bias) dieser erfahrenen Investoren in unbegrenzten Rahmenbedingungen. Nähe, empfundene Informationsvorteile und höhere erwartete Renditen werden als Begleitumstände bestätigt. Zusätzlich ist der Home Bias von Aktienfondsmanagern mit institutionellen und informatorischen Gegebenheiten sowie mit bestimmten Verhaltensmustern verbunden. Der empfundene Informationsvorteil scheint sich jedoch nicht zu bewahrheiten. Multivariate Analysen zeigen, dass der Home Bias hauptsächlich mit relativem Renditeoptimismus, der Nutzung nicht-fundamentaler Informationen und besonderem Risikoverhalten verbunden ist. Wir interpretieren diese Eigenschaften als unvollkommen rationales Verhalten. Konsistent zeigt sich, dass dieses Muster nicht für Rentenfondsmanager gilt

    Ambidextrie – der organisationale Drahtseilakt. Synergie zwischen Exploration und Exploitation als Voraussetzung für die digitale Transformation

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    Sich disruptiv verändernde Rahmenbedingungen können dazu führen, dass bisher erfolgreiche Geschäftsmodelle innert weniger Jahren obsolet werden. Geschuldet ist dies einer mangelnden Anpassungsfähigkeit, deren Ursache unter anderem in der sogenannten Pfadabhängigkeit wurzeln kann. Die Pfadabhängigkeit bezeichnet eine Situation, in der die Auswirkungen von stark durch die Vergangenheit geprägten Entscheiden dazu führen, dass die Möglichkeit bzw. Notwendigkeit neuer Geschäftsmodelle nicht erkannt, verpasst oder deren Chancen falsch eingeschätzt werden. Das Ausbrechen aus der Pfadabhängigkeit ist für den Fortbestand von Unternehmen daher von zentraler Bedeutung. Das Konzept der organisationalen Ambidextrie widmet sich dieser Problemstellung. Ambidextrie beschreibt die Fähigkeit eines Unternehmens, einerseits das Kerngeschäft stetig weiterzuentwickeln, gleichzeitig aber auch neue Wege und Denkweisen zu etablieren und so sicherzustellen, dass Veränderungen im Umsystem rechtzeitig erkannt und die sich dadurch bietenden Chancen für die Zukunft genutzt werden. Eine Fähigkeit, die gerade im Zeitalter der Digitalisierung an Wichtigkeit gewinnt

    C. elegans Agrin Is Expressed in Pharynx, IL1 Neurons and Distal Tip Cells and Does Not Genetically Interact with Genes Involved in Synaptogenesis or Muscle Function

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    Agrin is a basement membrane protein crucial for development and maintenance of the neuromuscular junction in vertebrates. The C. elegans genome harbors a putative agrin gene agr-1. We have cloned the corresponding cDNA to determine the primary structure of the protein and expressed its recombinant fragments to raise specific antibodies. The domain organization of AGR-1 is very similar to the vertebrate orthologues. C. elegans agrin contains a signal sequence for secretion, seven follistatin domains, three EGF-like repeats and two laminin G domains. AGR-1 loss of function mutants did not exhibit any overt phenotypes and did not acquire resistance to the acetylcholine receptor agonist levamisole. Furthermore, crossing them with various mutants for components of the dystrophin-glycoprotein complex with impaired muscle function did not lead to an aggravation of the phenotypes. Promoter-GFP translational fusion as well as immunostaining of worms revealed expression of agrin in buccal epithelium and the protein deposition in the basal lamina of the pharynx. Furthermore, dorsal and ventral IL1 head neurons and distal tip cells of the gonad arms are sources of agrin production, but no expression was detectable in body muscles or in the motoneurons innervating them. Recombinant worm AGR-1 fragment is able to cluster vertebrate dystroglycan in cultured cells, implying a conservation of this interaction, but since neither of these proteins is expressed in muscle of C. elegans, this interaction may be required in different tissues. The connections between muscle cells and the basement membrane, as well as neuromuscular junctions, are structurally distinct between vertebrates and nematodes

    Genome-wide interaction study of a proxy for stress-sensitivity and its prediction of major depressive disorder

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    Individual response to stress is correlated with neuroticism and is an important predictor of both neuroticism and the onset of major depressive disorder (MDD). Identification of the genetics underpinning individual differences in response to negative events (stress-sensitivity) may improve our understanding of the molecular pathways involved, and its association with stress-related illnesses. We sought to generate a proxy for stress-sensitivity through modelling the interaction between SNP allele and MDD status on neuroticism score in order to identify genetic variants that contribute to the higher neuroticism seen in individuals with a lifetime diagnosis of depression compared to unaffected individuals. Meta-analysis of genome-wide interaction studies (GWIS) in UK Biobank (N = 23,092) and Generation Scotland: Scottish Family Health Study (N = 7,155) identified no genome-wide significance SNP interactions. However, gene-based tests identified a genome-wide significant gene, ZNF366, a negative regulator of glucocorticoid receptor function implicated in alcohol dependence (p = 1.48x10-7; Bonferroni-corrected significance threshold p < 2.79x10-6). Using summary statistics from the stress-sensitivity term of the GWIS, SNP heritability for stress-sensitivity was estimated at 5.0%. In models fitting polygenic risk scores of both MDD and neuroticism derived from independent GWAS, we show that polygenic risk scores derived from the UK Biobank stress-sensitivity GWIS significantly improved the prediction of MDD in Generation Scotland. This study may improve interpretation of larger genome-wide association studies of MDD and other stress-related illnesses, and the understanding of the etiological mechanisms underpinning stress-sensitivity

    Hair Cortisol in Twins : Heritability and Genetic Overlap with Psychological Variables and Stress-System Genes

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    A. Palotie on työryhmän jäsen.Hair cortisol concentration (HCC) is a promising measure of long-term hypothalamus-pituitary-adrenal (HPA) axis activity. Previous research has suggested an association between HCC and psychological variables, and initial studies of inter-individual variance in HCC have implicated genetic factors. However, whether HCC and psychological variables share genetic risk factors remains unclear. The aims of the present twin study were to: (i) assess the heritability of HCC; (ii) estimate the phenotypic and genetic correlation between HPA axis activity and the psychological variables perceived stress, depressive symptoms, and neuroticism; using formal genetic twin models and molecular genetic methods, i.e. polygenic risk scores (PRS). HCC was measured in 671 adolescents and young adults. These included 115 monozygotic and 183 dizygotic twin-pairs. For 432 subjects PRS scores for plasma cortisol, major depression, and neuroticism were calculated using data from large genome wide association studies. The twin model revealed a heritability for HCC of 72%. No significant phenotypic or genetic correlation was found between HCC and the three psychological variables of interest. PRS did not explain variance in HCC. The present data suggest that HCC is highly heritable. However, the data do not support a strong biological link between HCC and any of the investigated psychological variables.Peer reviewe

    Multi-ancestry study of blood lipid levels identifies four loci interacting with physical activity.

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    Many genetic loci affect circulating lipid levels, but it remains unknown whether lifestyle factors, such as physical activity, modify these genetic effects. To identify lipid loci interacting with physical activity, we performed genome-wide analyses of circulating HDL cholesterol, LDL cholesterol, and triglyceride levels in up to 120,979 individuals of European, African, Asian, Hispanic, and Brazilian ancestry, with follow-up of suggestive associations in an additional 131,012 individuals. We find four loci, in/near CLASP1, LHX1, SNTA1, and CNTNAP2, that are associated with circulating lipid levels through interaction with physical activity; higher levels of physical activity enhance the HDL cholesterol-increasing effects of the CLASP1, LHX1, and SNTA1 loci and attenuate the LDL cholesterol-increasing effect of the CNTNAP2 locus. The CLASP1, LHX1, and SNTA1 regions harbor genes linked to muscle function and lipid metabolism. Our results elucidate the role of physical activity interactions in the genetic contribution to blood lipid levels
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