104 research outputs found
The bashful and the boastful : prestigious leaders and social change in Mesolithic Societies
The creation and maintenance of influential leaders and authorities is one of the key themes of archaeological and historical enquiry. However the social dynamics of authorities and leaders in the Mesolithic remains a largely unexplored area of study. The role and influence of authorities can be remarkably different in different situations yet they exist in all societies and in almost all social contexts from playgrounds to parliaments. Here we explore the literature on the dynamics of authority creation, maintenance and contestation in egalitarian societies, and discuss the implications for our interpretation and understanding of the formation of authorities and leaders and changing social relationships within the Mesolithic
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Diagnostic Components in Harsh Radiation Environments: Possible Overlap in R&D Requirements of IC and MF Systems
The next generation of large scale fusion devices--ITER/LMJ/NIF--will require diagnostic components to operate in environments far more severe than those encountered in present facilities. This harsh environment will be induced by fluxes of neutrons, gamma rays, energetic ions, electromagnetic radiation, and in some cases debris and shrapnel, at levels several orders of magnitude higher than those experienced in today's devices. For several years the question of possible synergy between inertial and the magnetic confinement research has been pursued by members of the respective communities. A first joint workshop specifically devoted to the identification and promotion of these synergies was organized in France, at Aix-en-Provence from June 27th to 29th, 2007. The workshop was attended by about 50 invited specialists. The participants identified a number of subject areas where common overlapping interests could benefit from additional interactions and meetings: windows, optical fibers, mirrors, cables, electronic components and 14 MeV neutron sources. In this paper we summarize the findings of these working groups. We put the discussion into context by including a brief description of the environments and the physical effects that have to be handled
Mechanisms of hypoxic up-regulation of versican gene expression in macrophages
Hypoxia is a hallmark of many pathological tissues. Macrophages accumulate in hypoxic sites and up-regulate a range of hypoxia-inducible genes. The matrix proteoglycan versican has been identified as one such gene, but the mechanisms responsible for hypoxic induction are not fully characterised. Here we investigate the up-regulation of versican by hypoxia in primary human monocyte-derived macrophages (HMDM), and, intriguingly, show that versican mRNA is up-regulated much more highly (>600 fold) by long term hypoxia (5 days) than by 1 day of hypoxia (48 fold). We report that versican mRNA decay rates are not affected by hypoxia, demonstrating that hypoxic induction of versican mRNA is mediated by increased transcription. Deletion analysis of the promoter identified two regions required for high level promoter activity of luciferase reporter constructs in human macrophages. The hypoxia-inducible transcription factor HIF-1 has previously been implicated as a key potential regulator of versican expression in hypoxia, however our data suggest that HIF-1 up-regulation is unlikely to be principally responsible for the high levels of induction observed in HMDM. Treatment of HMDM with two distinct specific inhibitors of Phosphoinositide 3-kinase (PI3K), LY290042 and wortmannin, significantly reduced induction of versican mRNA by hypoxia and provides evidence of a role for PI3K in hypoxic up-regulation of versican expression
EUROfusion contributions to ITER nuclear operation
ITER is of key importance in the European fusion roadmap as it aims to prove the scientific and
technological feasibility of fusion as a future energy source. The EUROfusion consortium of
labs within Europe is contributing to the preparation of ITER scientific exploitation and
operation and aspires to exploit ITER outcomes in view of DEMO. The paper provides an
overview of the major progress obtained recently, carried out in the frame of the new (initiated
in 2021) EUROfusion work-package called ‘Preparation of ITER Operation’ (PrIO). The
overview paper is directly supported by the eleven EUROfusion PrIO contributions given at the
29th Fusion Energy Conference (16–21 October 2023) London, UK [www.iaea.org/events/
fec2023]. The paper covers the following topics: (i) development and validation of tools in
support to ITER operation (plasma breakdown/burn-through with evolving plasma volume, new
infra-red synthetic diagnostic for off-line analysis and wall monitoring using Artificial
Intelligence techniques, synthetic diagnostics development, development and exploitation of
multi-machine databases); (ii) R&D for the radio-frequency ITER neutral beam sources leading
to long duration of negative deuterium/hydrogen ions current extraction at ELISE and
participation in the neutral beam test facility with progress on the ITER source SPIDER, and,
the commissioning of the 1 MV high voltage accelerator (MITICA) with lessons learned for
ITER; (iii) validation of neutronic tools for ITER nuclear operation following the second JET
deuterium–tritium experimental campaigns carried out in 2021 and in 2023 (neutron streaming
and shutdown dose rate calculation, water activation and activated corrosion products with
advanced fluid dynamic simulation; irradiation of several materials under 14.1 MeV neutron
flux etc)
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