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Dossier. Corps antiques : morceaux choisis

ISBN: 9782713231735 DOI: 10.4000/books.editionsehess.13659 Language: French
Publisher: Éditions de l’École des hautes études en sciences sociales
Subject: History
Added to DOAB on : 2019-12-06 13:15:29
License: OpenEdition Licence for Books

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Le dossier « Corps antiques : morceaux choisis » s’intéresse aux représentations d’un membre ou d’un organe conçu dans sa singularité, aux dispositifs d’isolement et de distinction visuels et symboliques dans les discours, les images, les assemblages votifs grecs et romains, et les constructions muséographiques contemporaines.

Keywords

body --- body in pieces --- memory --- assembly --- collection

Self-Organization in the Nervous System

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889453405 Year: Pages: 135 DOI: 10.3389/978-2-88945-340-5 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Neurology
Added to DOAB on : 2018-02-27 16:16:45
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This special issue reviews state-of-the-art approaches to the biophysical roots of cognition. These approaches appeal to the notion that cognitive capacities serve to optimize responses to changing external conditions. Crucially, this optimisation rests on the ability to predict changes in the environment, thus allowing organisms to respond pre-emptively to changes before their onset. The biophysical mechanisms that underwrite these cognitive capacities remain largely unknown; although a number of hypotheses has been advanced in systems neuroscience, biophysics and other disciplines. These hypotheses converge on the intersection of thermodynamic and information-theoretic formulations of self-organization in the brain. The latter perspective emerged when Shannon’s theory of message transmission in communication systems was used to characterise message passing between neurons. In its subsequent incarnations, the information theory approach has been integrated into computational neuroscience and the Bayesian brain framework. The thermodynamic formulation rests on a view of the brain as an aggregation of stochastic microprocessors (neurons), with subsequent appeal to the constructs of statistical mechanics and thermodynamics. In particular, the use of ensemble dynamics to elucidate the relationship between micro-scale parameters and those of the macro-scale aggregation (the brain). In general, the thermodynamic approach treats the brain as a dissipative system and seeks to represent the development and functioning of cognitive mechanisms as collective capacities that emerge in the course of self-organization. Its explicanda include energy efficiency; enabling progressively more complex cognitive operations such as long-term prediction and anticipatory planning. A cardinal example of the Bayesian brain approach is the free energy principle that explains self-organizing dynamics in the brain in terms of its predictive capabilities – and selective sampling of sensory inputs that optimise variational free energy as a proxy for Bayesian model evidence. An example of thermodynamically grounded proposals, in this issue, associates self-organization with phase transitions in neuronal state-spaces; resulting in the formation of bounded neuronal assemblies (neuronal packets). This special issue seeks a discourse between thermodynamic and informational formulations of the self-organising and self-evidencing brain. For example, could minimization of thermodynamic free energy during the formation of neuronal packets underlie minimization of variational free energy?

Synaptic Assembly and Neural Circuit Development

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889456307 Year: Pages: 191 DOI: 10.3389/978-2-88945-630-7 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Neurology
Added to DOAB on : 2019-01-23 14:53:43
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Synapses are fundamental signaling units of the central nervous system that mediate communication between individual neurons, participate in the computation of neuronal networks, and process information through long-term modification of their strength and structure. The normal function of the central nervous system critically depends on the establishment of ‘precise’ synaptic connections between neurons and specific target cells. During synaptogenesis, synapses form, mature, stabilize, and are eliminated through processes that require intimate communication between pre- and postsynaptic partners. The sequential and/or parallel processes dictate the wiring of neural circuits in a rapid and dynamic fashion. Accumulating evidence suggests that activity-dependent synaptic and circuit plasticity reflects the assembly and disassembly of diverse synapses that occur in a distinctive manner in specific neuron types.In this Research Topic, our purpose is to compile the latest developments in our understanding of molecular and cellular mechanisms underlying pre- and postsynaptic assembly, specification of synaptic adhesion pathways, presynaptic neurotransmitter release and postsynaptic receptor trafficking. In addition, non-neuronal cell processes involved in dismantling and eliminating synapses and relevant neural circuits will be covered. Clinical implications of this research topic will be considered, emphasizing the importance of these basic neuroscience research activities for translational and therapeutic applications. This includes literature describing recent methodologies for probing key issues regarding assembly/disassembly of synapses and circuits as well as primary research articles that provide critical insights into these fundamental questions in various model systems and experimental preparations.

Spiking Neural Network Connectivity and its Potential for Temporal Sensory Processing and Variable Binding

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889192397 Year: Pages: 123 DOI: 10.3389/978-2-88919-239-7 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2015-11-16 15:44:59
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The most biologically-inspired artificial neurons are those of the third generation, and are termed spiking neurons, as individual pulses or spikes are the means by which stimuli are communicated. In essence, a spike is a short-term change in electrical potential and is the basis of communication between biological neurons. Unlike previous generations of artificial neurons, spiking neurons operate in the temporal domain, and exploit time as a resource in their computation. In 1952, Alan Lloyd Hodgkin and Andrew Huxley produced the first model of a spiking neuron; their model describes the complex electro-chemical process that enables spikes to propagate through, and hence be communicated by, spiking neurons. Since this time, improvements in experimental procedures in neurobiology, particularly with in vivo experiments, have provided an increasingly more complex understanding of biological neurons. For example, it is now well understood that the propagation of spikes between neurons requires neurotransmitter, which is typically of limited supply. When the supply is exhausted neurons become unresponsive. The morphology of neurons, number of receptor sites, amongst many other factors, means that neurons consume the supply of neurotransmitter at different rates. This in turn produces variations over time in the responsiveness of neurons, yielding various computational capabilities. Such improvements in the understanding of the biological neuron have culminated in a wide range of different neuron models, ranging from the computationally efficient to the biologically realistic. These models enable the modelling of neural circuits found in the brain. In recent years, much of the focus in neuron modelling has moved to the study of the connectivity of spiking neural networks. Spiking neural networks provide a vehicle to understand from a computational perspective, aspects of the brain's neural circuitry. This understanding can then be used to tackle some of the historically intractable issues with artificial neurons, such as scalability and lack of variable binding. Current knowledge of feed-forward, lateral, and recurrent connectivity of spiking neurons, and the interplay between excitatory and inhibitory neurons is beginning to shed light on these issues, by improved understanding of the temporal processing capabilities and synchronous behaviour of biological neurons. This research topic aims to amalgamate current research aimed at tackling these phenomena.

Viral Replication Complexes: Structures, Functions, Applications and Inhibitors

ISBN: 9783038421672 9783038421689 Year: Pages: XVI, 428 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Added to DOAB on : 2016-07-14 07:43:51
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Viruses are obligate intracellular parasites that need to co-opt a living cell’s machinery for replication. At the heart of the viral replication machinery are the nucleic acid polymerases, which are responsible for efficiently copying the viral genome. This process must often be coordinated with other viral processes including protein translation and viral packaging. The nucleic acid polymerases may also be responsible for generating genetic diversity that is important for escape from the host’s defenses. The polymerases and other components of the replication machinery may serve as potential anti-viral targets. In this Special Issue, we seek to highlight recent advances into uncovering the structure and function of viral replication complexes. We are especially seeking to highlight the wide-range of methodologies used to gain structural insight into viral replication. Topics of interest include molecular mechanisms of nucleic acid polymerases, nucleic acid recognition and translocation, fidelity and error correction, interactions with lipid membranes, and coordination/regulation of transcription, translation and replication processes.

Colloid Chemistry

Authors: ---
ISBN: 9783038974598 9783038974604 Year: Pages: 232 DOI: 10.3390/books978-3-03897-460-4 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Chemistry (General)
Added to DOAB on : 2019-01-15 11:06:27
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The Special Issue Colloid Chemistry presents a comprehensive overview of what opportunities the colloidal scale, i.e., the nanoscale, offers to scientists from chemistry, physics, materials sciences, and biomedicine. Sophistically designed colloids are used for studying physical and physicochemical phenomena to gain a deeper understanding of interparticle interactions, not forgetting that such insights can be used to create tailored materials for a variety of applications. This Issue covers aspects from the synthesis to the analysis of colloidal properties and presents opportunities for their further application.

Self-Assembled Bio-Nanomaterials: Synthesis, Characterization, and Applications

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ISBN: 9783039285365 9783039285372 Year: Pages: 134 DOI: 10.3390/books978-3-03928-537-2 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering --- Materials
Added to DOAB on : 2020-04-07 23:07:09
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Biomolecular self-assembly provides a green, facile, and highly effective method to synthesize various functional nanomaterials that have exhibited considerable potential in the fields of nanotechnology, materials science, biomedicine, tissue engineering, food science, energy storage, and environmental science. In this collection of articles, we presented recent advance in the synthesis, characterization, and applications of self-assembled bio-nanomaterials. In a comprehensive review article, the controlled self-assembly of biomolecules including DNA, protein, peptide, enzymes, virus, and biopolymers via internal interactions and external simulations is introduced and discussed in detail. In other research articles, the self-assembly of DNA, protein, peptide, bio-drugs, liquid crystal polycarbonates, and diblock copolymers to various biomimetic/bioinspired nanomaterials and their potential applications in nanopatterning, sensors/biosensors, drug delivery, anti-parasite, and water purification are demonstrated.

Self-Assembly of Polymers

Authors: ---
ISBN: 9783039285068 / 9783039285075 Year: Pages: 186 DOI: 10.3390/books978-3-03928-507-5 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2020-06-09 16:38:57
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Nowadays, polymer self-assembly has become extremely attractive for both biological (drug delivery, tissue engineering, scaffolds) and non-biological (packaging, semiconductors) applications. In nature, a number of key biological processes are driven by polymer self-assembly, for instance protein folding. Impressive morphologies can be assembled from polymers thanks to a diverse range of interactions involved, e.g., electrostatics, hydrophobic, hots-guest interactions, etc. Both 2D and 3D tailor-made assemblies can be designed through modern powerful techniques and approaches such as the layer-by-layer and the Langmuir-Blodgett deposition, hard and soft templating. This Special Issue highlights contributions (research papers, short communications, review articles) that focus on recent developments in polymer self-assembly for both fundamental understanding the assembly phenomenon and real applications.

The causes and consequences of microbial community structure

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193615 Year: Pages: 184 DOI: 10.3389/978-2-88919-361-5 Language: English
Publisher: Frontiers Media SA
Subject: Microbiology --- Science (General)
Added to DOAB on : 2015-11-19 16:29:12
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The causes and consequences of differences in microbial community structure, defined here as the relative proportions of rare and abundant organisms within a community, are poorly understood. Articles in "The Causes and Consequences of Microbial Community Structure", use empirical or modeling approaches as well as literature reviews to enrich our mechanistic understanding of the controls over the relationship between community structure and ecosystem processes. Specifically, authors address the role of trait distributions and tradeoffs, species-species interactions, evolutionary dynamics, community assembly processes and physical controls in affecting ‘who’s there’ and ‘what they are doing’.

Biogenesis of the oxidative phosphorylation machinery in plants. From gene expression to complex assembly

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889192786 Year: Pages: 98 DOI: 10.3389/978-2-88919-278-6 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Physiology --- Botany
Added to DOAB on : 2015-12-03 13:02:24
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Mitochondrial biogenesis is an extremely complex process. A hint of this complexity is clearly indicated by the many steps and factors required to assemble the respiratory complexes involved in oxidative phosphorylation. These steps include the expression of genes present in both the nucleus and the organelle, intricate post-transcriptional RNA processing events, the coordinated synthesis, transport and assembly of the different subunits, the synthesis and assembly of co-factors and, finally, the formation of supercomplexes or respirasomes. It can be envisaged, and current knowledge supports this view, that plants have evolved specific mechanisms for the biogenesis of respiratory complexes. For example, expression of the mitochondrial genome in plants has special features, not present in other groups of eukaryotes. Moreover, plant mitochondrial biogenesis and function should be considered in the context of the presence of the chloroplast, a second organelle involved in energetic and redox metabolism. It implies the necessity to discriminate between proteins destined for each organelle and requires the establishment of functional interconnections between photosynthesis and respiration. In recent years, our knowledge of the mechanisms involved in these different processes in plants has considerably increased. As a result, the many events and factors necessary for the correct expression of proteins encoded in the mitochondrial genome, the cis acting elements and factors responsible for the expression of nuclear genes encoding respiratory chain components, the signals and mechanisms involved in the import of proteins synthesized in the cytosol and the many factors required for the synthesis and assembly of the different redox co-factors (heme groups, iron-sulfur clusters, copper centers) are beginning to be recognized at the molecular level. However, detailed knowledge of these processes is still not complete and, especially, little is known about how these processes are interconnected. Questions such as how the proteins, once synthesized in the mitochondrial matrix, are inserted into the membrane and assembled with other components, including those imported from the cytosol, how the expression of both genomes is coordinated and responds to changes in mitochondrial function, cellular requirements or environmental cues, or which factors and conditions influence the assembly of complexes and supercomplexes are still open and will receive much attention in the near future. This Research Topic is aimed at establishing a collection of articles that focus on the different processes involved in the biogenesis of respiratory complexes in plants as a means to highlight recent advances. In this way, it intends to help to construct a picture of the whole process and, not less important, to expose the existing gaps that need to be addressed to fully understand how plant cells build and modulate the complex structures involved in respiration.

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