Analysis of global diversity patterns and dynamics of selected Mesozoic marine invertebrate groups

Megjegyzés az értekezés megjelenítéséről: a szerző kérésére a disszertáció 2017-08-31-től lehet nyilvános; a tézisek olvashatóak

Blockchain-Based, Confidentiality-Preserving Orchestration of Collaborative Workflows

Business process collaboration between independent parties can be challenging, especially if the participants do not have complete trust in each other. Tracking actions and enforcing the activity authorizations of participants via blockchain-hosted smart contracts is an emerging solution to this lack of trust, with most state-of-the-art approaches generating the orchestrating smart contract logic from BPMN models. However, as a significant drawback in comparison to centralized business process orchestration, smart contract state typically leaks potentially sensitive information about the state of the collaboration. We describe a novel approach where the process manager smart contract only stores cryptographic commitments to the state and checks zero-knowledge proofs on update proposals. We cover a representative subset of BPMN, support message passing commitments between participants and provide an open-source end-to-end implementation. Under our approach, no party external to the collaboration can gain trustable knowledge of the current state of a process instance (barring collusion with a participant), even if it has full access to the blockchain history

Az oktatási reNdszER kritikája: Radó Péter: Közoktatás és politika

Radó Péter (2022). Közoktatás és politika – Magyarország 2010–2022. Noran Libro Kft

MASS EXTINCTIONS AND CLADE EXTINCTIONS IN THE HISTORY OF BRACHIOPODS: BRIEF REVIEW AND A POST-PALEOZOIC CASE STUDY

Brachiopods are a key group in Phanerozoic marine diversity analyses for their excellent fossil record and distinctive evolutionary history. A genus-level survey of raw diversity trajectories allows the identification of the Brachiopod Big Five, episodes of major genus losses in the phylum which are compared with the established Big Five mass extinctions of Phanerozoic marine invertebrates. The two lists differ in that the end-Cretaceous extinction appears subdued for brachiopods, whereas the mid-Carboniferous is recognized as an event with significant loss of brachiopod genera. At a higher taxonomic level, a review of temporal ranges of rhynchonelliform orders reveals episodes of synchronous termination of multiple orders, here termed clade extinctions. The end-Ordovician, Late Devonian and end-Permian events are registered as both mass extinctions and clade extinctions. The Late Cambrian and the Early Jurassic are identified as the other two clade extinction events. Coincident with the Early Toarcian oceanic anoxic event, the last clade extinction of brachiopods is defined by the disappearance of the last two spire-bearing orders, Athyridida and Spiriferinida. Their diversity trajectory through the recovery after the end-Permian crisis parallels that of the extant terebratulides and rhynchonellides until a Late Triassic peak but diverge afterwards. The end-Triassic diversity decline and Toarcian vanishing of spire-bearers correspond with contraction in their spatial distribution. The observed patterns and extinction selectivity may be explained both ecologically and physiologically. The specialized adaptation of morphologically diverse spire-bearers, as well as their fixed lophophore and passive feeding put them at a disadvantage at times of environmental crises, manifest in their end-Triassic near-extinction and Toarcian demise. Similar analyses of other clade extinctions may further improve our understanding of drivers and processes of extinction

Adding fossil occupancy trajectories to the assessment of modern extinction risk

Besides helping to identify species traits that are commonly linked to extinction risk, the fossil record may also be directly relevant for assessing the extinction risk of extant species. Standing geographical distribution or occupancy is a strong predictor of both recent and past extinction risk, but the role of changes in occupancy is less widely assessed. Here we demonstrate, based on the Cenozoic fossil record of marine species, that both occupancy and its temporal trajectory are significant determinants of risk. Based on extinct species we develop a model on the additive and interacting effects of occupancy and its temporal changes on extinction risk. We use this model to predict extinction risk of extant species. The predictions suggest a moderate risk for marine species on average. However, some species seem to be on a long-term decline and potentially at a latent extinction risk, which is not considered in current risk assessments

Not all biodiversity rich spots are climate refugia

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