A Survey on Content Retrieval on the Decentralised Web

The control, governance, and management of the web have become increasingly centralised, resulting in security, privacy, and censorship concerns. Decentralised initiatives have emerged to address these issues, beginning with decentralised file systems. These systems have gained popularity, with major platforms serving millions of content requests daily. Complementing the file systems are decentralised search engines and name registry infrastructures, together forming the basis of a decentralised web. This survey paper analyses research trends and emerging technologies for content retrieval on the decentralised web, encompassing both academic literature and industrial projects. Several challenges hinder the realisation of a fully decentralised web. Achieving comparable performance to centralised systems without compromising decentralisation is a key challenge. Hybrid infrastructures, blending centralised components with verifiability mechanisms, show promise to improve decentralised initiatives. While decentralised file systems have seen more mature deployments, they still face challenges such as usability, performance, privacy, and content moderation. Integrating these systems with decentralised name-registries offers a potential for improved usability with human-readable and persistent names for content. Further research is needed to address security concerns in decentralised name-registries and enhance governance and crypto-economic incentive mechanisms

Modeling cellular deformations using the level set formalism

BACKGROUND: Many cellular processes involve substantial shape changes. Traditional simulations of these cell shape changes require that grids and boundaries be moved as the cell's shape evolves. Here we demonstrate that accurate cell shape changes can be recreated using level set methods (LSM), in which the cellular shape is defined implicitly, thereby eschewing the need for updating boundaries. RESULTS: We obtain a viscoelastic model of Dictyostelium cells using micropipette aspiration and show how this viscoelastic model can be incorporated into LSM simulations to recreate the observed protrusion of cells into the micropipette faithfully. We also demonstrate the use of our techniques by simulating the cell shape changes elicited by the chemotactic response to an external chemoattractant gradient. CONCLUSION: Our results provide a simple but effective means of incorporating cellular deformations into mathematical simulations of cell signaling. Such methods will be useful for simulating important cellular events such as chemotaxis and cytokinesis

Cellular development and evolution of the mammalian cerebellum

\ua9 2023, The Author(s).The expansion of the neocortex, a hallmark of mammalian evolution 1,2, was accompanied by an increase in cerebellar neuron numbers 3. However, little is known about the evolution of the cellular programmes underlying the development of the cerebellum in mammals. In this study we generated single-nucleus RNA-sequencing data for around 400,000 cells to trace the development of the cerebellum from early neurogenesis to adulthood in human, mouse and the marsupial opossum. We established a consensus classification of the cellular diversity in the developing mammalian cerebellum and validated it by spatial mapping in the fetal human cerebellum. Our cross-species analyses revealed largely conserved developmental dynamics of cell-type generation, except for Purkinje cells, for which we observed an expansion of early-born subtypes in the human lineage. Global transcriptome profiles, conserved cell-state markers and gene-expression trajectories across neuronal differentiation show that cerebellar cell-type-defining programmes have been overall preserved for at least 160 million years. However, we also identified many orthologous genes that gained or lost expression in cerebellar neural cell types in one of the species or evolved new expression trajectories during neuronal differentiation, indicating widespread gene repurposing at the cell-type level. In sum, our study unveils shared and lineage-specific gene-expression programmes governing the development of cerebellar cells and expands our understanding of mammalian brain evolution

Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.

Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field

Laz positional verbs: semantics and use with inanimate Figures

In this article, we discuss the meaning and use of positional verbs in the South-Caucasian language Laz. Positional verbs are defined as those verbs which — in combination with one of several locational verbal prefixes (preverbs) — may appear in the basic construction that functions as an answer to a “where” question, the so-called basic locative construction (BLC). Within this class of verbs, we pay particular attention to those positionals which are used regularly in our data to describe the configuration of inanimate movable objects. Laz is shown to be a multiverb language, i.e., a language that uses a comparatively large set of verbs in the BLC. The fourteen verbs in question are PRV-dgun ‘stand’, PRV-ren ‘stand’, PRV-zun ‘lie’, PRV-xen ‘sit, stay’, PRV-bɣun ‘be located as mass’, PRV-mpiy ‘be spread’, PRV-sun ‘be smeared’, PRV-tun ‘cover’, PRV-bun ‘hang’, PRV-nʒoy ‘stick, be stuck’, PRV-n un ‘be dipped’, PRV- abun ‘stick to, be sticky’, PRV- orun ‘be bound’, PRV-gzun ‘burn’. The semantics and the use of these verbs are described in some detail including nontypical configurations, which trigger variation among speakers due to alternative categorizations and prototype effects