438 research outputs found
On Conflict-Free Replicated Data Types and Equivocation in Byzantine Setups
We explore the property of equivocation tolerance for Conflict-Free Replicated Data Types (CRDTs). We show that a subclass of CRDTs is equivocation-tolerant and can thereby cope with any number of Byzantine faults: Without equivocation detection, prevention or remediation, they still fulfill strong eventual consistency (SEC). We also conjecture that there is only one operation-based CRDT design supporting non-commutative operations that fulfills SEC in Byzantine environments with any number of faults
On Conflict-Free Replicated Data Types and Equivocation in Byzantine Setups
We explore the property of equivocation tolerance for Conflict-Free Replicated Data Types (CRDTs). We show that a subclass of CRDTs is equivocation-tolerant and can thereby cope with any number of Byzantine faults: Without equivocation detection, prevention or remediation, they still fulfill strong eventual consistency (SEC). We also conjecture that there is only one operation-based CRDT design supporting non-commutative operations that fulfills SEC in Byzantine environments with any number of faults
On CRDTs in Byzantine Environments : Conflict Freedom, Equivocation Tolerance, and the Matrix Replicated Data Type
On CRDTs in Byzantine Environments : Conflict Freedom, Equivocation Tolerance, and the Matrix Replicated Data Type
Einfluss von körperlicher AktivitÀt auf die Ausbildung einer Aortenklappensklerose im Tiermodell der LDL-Rezeptor-knockout-Maus
RegelmĂ€Ăige körperliche AktivitĂ€t verlangsamt die Progression arteriosklerotischer LĂ€sionen, reduziert oxidativen Stress und erhöht die BioverfĂŒgbarkeit von Stickstoffmonoxid. Von diesen VorgĂ€ngen erwartet man auch eine Verbesserung des Outcomes bei degenerativen Aortenklappenerkrankungen. Ziel der vorliegenden Arbeit war es den Effekt von körperlicher AktivitĂ€t im Sinne einer PrimĂ€rprĂ€vention auf die Ausbildung einer Aortenklappensklerose, die ein frĂŒhes Stadium in der Entwicklung einer Aortenklappenstenose darstellt, mit ihrem zu Grunde liegendem Pathomechanismus zu untersuchen.
HierfĂŒr wurde das Tiermodell der LDL-Rezeptor-knockout-Maus gewĂ€hlt, da bereits in Studien die regelhafte Induktion von Aortenklappensklerosen und hĂ€modynamisch relevante Stenosen durch cholesterinreiche Nahrung gezeigt werden konnte.
FĂŒr die vorliegende Studie wurden 4 Wochen alte LDL-Rezeptor-knockout-MĂ€use in 4 Gruppen randomisiert: Eine Kontroll-Gruppe mit normaler DiĂ€t und bewegungsarmen Lebensstil, eine Cholesterin-Gruppe mit cholesterinreicher ErnĂ€hrung und bewegungsarmen Lebensstil, eine regelmĂ€Ăige Trainingsgruppe mit cholesterinreicher ErnĂ€hrung und regelmĂ€Ăiger körperlicher AktivitĂ€t (60 min/d, 5 Tage/Woche) und eine gelegentlichen Trainingsgruppe, mit cholesterinreicher ErnĂ€hung und körperlicher AktivitĂ€t (60 min/d, 1 Tag/Woche) fĂŒr jeweils 16 Wochen. In der 20. Woche wurden histologische Untersuchungen vorgenommen, die Verdickungen der Aortenklappen in der Cholesterin-Gruppe verglichen zur Kontroll-Gruppe zeigten. RegelmĂ€Ăige, jedoch keine gelegentliche körperliche AktivitĂ€t reduziert signifikant diese Verdickung der Aortenklappe. Die immunhistochemischen Untersuchungen zeigten, dass eine Cholesterin-DiĂ€t die EndothelintegritĂ€t der Aortenklappe zerstört, wohingegen sie durch regelmĂ€Ăige körperliche AktivitĂ€t geschĂŒtzt wird. Weiterhin zeigte sich eine Erhöhung der Serum-Myeloperoxidase, der oxidierten Low Density Lipoproteine, der in situ Superoxide, als Marker fĂŒr oxidativen Stress. Es konnten erhöhte Spiegel fĂŒr Mac3, als Marker fĂŒr Makrophagenakkumulation, α-smooth muscle actin, als Marker fĂŒr Klappenfibrose und der proosteogene Marker Alkalische Phosphatase sowie eine erhöhte Mineralisation in der Cholesterin-Gruppe nachgewiesen werden. Wohingegen die genannten Marker in der Gruppe mit regelmĂ€Ăiger körperlicher AktivitĂ€t erniedrigt nachgewiesen werden konnten. Die Ergebnisse der Polymerase-Kettenreaktion ergaben eine erhöhte Expression der messenger-RNA fĂŒr α-smooth muscle actin, bone morphogentic protein-2, runt- related transcription factor-2 und Alkalische Phosphatase, als Marker fĂŒr Klappenfibrose und Proosteogenese in der Cholesterin-Gruppe, dagegen waren sie durch regelmĂ€Ăige körperliche AktivitĂ€t erniedrigt. DarĂŒber hinaus erhöht regelmĂ€Ăige körperliche AktivitĂ€t signifikant die Spiegel von zirkulierendem Fetuin-A, als Hemmstoff der Kalzifizierung verglichen zur Cholesterin-Gruppe.
Schlussfolgernd lĂ€sst sich sagen, dass regelmĂ€Ăige, jedoch keine gelegentliche körperliche AktivitĂ€t einer Aortenklappensklerose im Sinne einer PrimĂ€rprĂ€vention durch eine Anzahl von Mechanismen, wie dem Schutz der EndothelintegritĂ€t, der Reduktion von Inflammation und oxidativem Stress sowie der Hemmung des osteogenen Signalweges, vorbeugt
Age-related macular degeneration associated polymorphism rs10490924 in ARMS2 results in deficiency of a complement activator
Background Age-related macular degeneration (AMD) is the leading cause of
blindness in developed countries. The polymorphism rs10490924 in the ARMS2
gene is highly associated with AMD and linked to an indel mutation
(del443ins54), the latter inducing mRNA instability. At present, the function
of the ARMS2 protein, the exact cellular sources in the retina and the
biological consequences of the rs10490924 polymorphism are unclear. Methods
Recombinant ARMS2 was expressed in Pichia pastoris, and protein functions were
studied regarding cell surface binding and complement activation in human
serum using fluoresence-activated cell sorting (FACS) as well as laser
scanning microscopy (LSM). Biolayer interferometry defined protein
interactions. Furthermore, endogenous ARMS2 gene expression was studied in
human blood derived monocytes and in human induced pluripotent stem cell-
derived microglia (iPSdM) by PCR and LSM. The ARMS2 protein was localized in
human genotyped retinal sections and in purified monocytes derived from AMD
patients without the ARMS2 risk variant by LSM. ARMS2 expression in monocytes
under oxidative stress was determined by Western blot analysis. Results Here,
we demonstrate for the first time that ARMS2 functions as surface complement
regulator. Recombinant ARMS2 binds to human apoptotic and necrotic cells and
initiates complement activation by recruiting the complement activator
properdin. ARMS2-properdin complexes augment C3b surface opsonization for
phagocytosis. We also demonstrate for the first time expression of ARMS2 in
human monocytes especially under oxidative stress and in microglia cells of
the human retina. The ARMS2 protein is absent in monocytes and also in
microglia cells, derived from patients homozygous for the ARMS2 AMD risk
variant (rs10490924). Conclusions ARMS2 is likely involved in complement-
mediated clearance of cellular debris. As AMD patients present with
accumulated proteins and lipids on Bruchâs membrane, ARMS2 protein deficiency
due to the genetic risk variant might be involved in drusen formation
Longitudinal Development of Primary and Secondary Posttraumatic Growth in Aging Veterans and Their Wives: Domain-Specific Trajectories
Posttraumatic growth (PTG), the positive psychological transformations that follow traumatic events, affects both direct survivors (primary PTG) and their significant others (secondary PTG). Though primary and secondary PTG have been widely investigated in the literature, their long-term trajectories decades after a traumatic event, especially as survivors enter older age, remain largely uninvestigated. Furthermore, it remains contested whether PTG adds up to a monolithic construct or rather consists of relatively independent components. Addressing these issues, we assessed a sample of Israeli male veterans from the 1973 Yom Kippur war (N = 349) and their wives (N = 156) at three time points over the course of nearly three decades. Both the veterans (primary survivors) and their wives (secondary survivors) reported PTG relating to the veterans' experiences during the war and/or captivity. Latent growth mixture modeling was conducted to identify trajectories of PTG on the five subscales of the Posttraumatic Growth Inventory. Long-term trajectories of PTG followed heterogeneous patterns of fluctuation over time and particularly as participants entered older age. On most subscales, decreasing PTG scores were evident, a trend that was more pronounced among the primary survivors than the secondary survivors as primary and secondary PTG fluctuate considerably in the long-term and seem to decrease as individuals enter older age. Furthermore, it would seem that PTG should not be considered a holistic concept but rather a conglomeration of positive changes. Implications of the findings are discussed within the context of limitations and potential intervening factors
BlueSky: Combining Task Planning and Activity-Centric Access Control for Assistive Humanoid Robots
In the not too distant future, assistive humanoid robots will provide versatile assistance for coping with everyday life. In their interactions with humans, not only safety, but also security and privacy issues need to be considered. In this Blue Sky paper, we therefore argue that it is time to bring task planning and execution as a well-established field of robotics with access and usage control in the field of security and privacy closer together. In particular, the recently proposed activity-based view on access and usage control provides a promising approach to bridge the gap between these two perspectives. We argue that humanoid robots provide for specific challenges due to their task-universality and their use in both, private and public spaces. Furthermore, they are socially connected to various parties and require policy creation at runtime due to learning. We contribute first attempts on the architecture and enforcement layer as well as on joint modeling, and discuss challenges and a research roadmap also for the policy and objectives layer. We conclude that the underlying combination of decentralized systems\u27 and smart environments\u27 research aspects provides for a rich source of challenges that need to be addressed on the road to deployment
Mental Health Impact of Early Stages of the COVID-19 Pandemic on Individuals with Pre-Existing Mental Disorders
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