98 research outputs found

    Mechanical Design Aspects of The LHC Beam screen

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    Forty-four kilometers of the LHC beam vacuum system [1,2] will be equipped with a perforated co-axial liner, the so-called beam screen. Operating between 5 K and 20 K, the beam screen reduces heat loads to the 1.9 K helium bath of the superconducting magnets and minimises dynamic vacuum effects. Constructed from low magnetic permeability stainless steel with a 50 mm inner layer of high purity copper, the beam screen must provide a maximum aperture for the beam whilst resisting the induced forces due to eddy currents at magnet quench. The mechanical engineering challenges are numerous, and include stringent requirements on geometry, material selection, manufacturing techniques and cleanliness. The industrial fabrication of these 16 metre long UHV components is now in its prototyping phase. A description of the beam screen is given, together with details of the experimental programme aimed at validating the design choices, and results of the first industrial prototypes

    CD98 Increases Renal Epithelial Cell Proliferation by Activating MAPKs

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    CD98 heavy chain (CD98hc) is a multifunctional transmembrane spanning scaffolding protein whose extracellular domain binds with light chain amino acid transporters (Lats) to form the heterodimeric amino acid transporters (HATs). It also interacts with β1 and β3 integrins by its transmembrane and cytoplasmic domains. This interaction is proposed to be the mechanism whereby CD98 mediates cell survival and growth via currently undefined signaling pathways. In this study, we determined whether the critical function of CD98-dependent amino acid transport also plays a role in cell proliferation and defined the signaling pathways that mediate CD98-dependent proliferation of murine renal inner medullary collecting duct (IMCD) cells. We demonstrate that downregulating CD98hc expression resulted in IMCD cell death. Utilizing overexpression studies of CD98hc mutants that either lacked a cytoplasmic tail or were unable to bind to Lats we showed that CD98 increases serum-dependent cell proliferation by a mechanism that requires the CD98hc cytoplasmic tail. We further demonstrated that CD98-dependent amino acid transport increased renal tubular epithelial cell proliferation by a mechanism that does not require the CD98hc cytoplasmic tail. Both these mechanisms of increased renal tubular epithelial cell proliferation are mediated by Erk and p38 MAPK signaling. Although increased amino transport markedly activated mTor signaling, this pathway did not alter cell proliferation. Thus, these studies demonstrate that in IMCD cells, the cytoplasmic and extracellular domains of CD98hc regulate cell proliferation by distinct mechanisms that are mediated by common MAPK signaling pathways

    Regional and local environmental conditions do not shape the response to warming of a marine habitat-forming species

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    The differential response of marine populations to climate change remains poorly understood. Here, we combine common garden thermotolerance experiments in aquaria and population genetics to disentangle the factors driving the population response to thermal stress in a temperate habitatforming species: the octocoral Paramuricea clavata. Using eight populations separated from tens of meters to hundreds of kilometers, which were differentially impacted by recent mortality events, we identify 25 degrees C as a critical thermal threshold. After one week of exposure at this temperature, seven of the eight populations were affected by tissue necrosis and after 30 days of exposure at this temperature, the mean % of affected colonies increased gradually from 3 to 97%. We then demonstrate the weak relation between the observed differential phenotypic responses and the local temperature regimes experienced by each population. A significant correlation was observed between these responses and the extent of genetic drift impacting each population. Local adaptation may thus be hindered by genetic drift, which seems to be the main driver of the differential response. Accordingly, conservation measures should promote connectivity and control density erosion in order to limit the impact of genetic drift on marine populations facing climate change

    Beyond knowing nature: Contact, emotion, compassion, meaning, and beauty are pathways to nature connection

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    Feeling connected to nature has been shown to be beneficial to wellbeing and pro-environmental behaviour. General nature contact and knowledge based activities are often used in an attempt to engage people with nature. However the specific routes to nature connectedness have not been examined systematically. Two online surveys (total n = 321) of engagement with, and value of, nature activities structured around the nine values of the Biophila Hypothesis were conducted. Contact, emotion, meaning, and compassion, with the latter mediated by engagement with natural beauty, were predictors of connection with nature, yet knowledge based activities were not. In a third study (n = 72), a walking intervention with activities operationalising the identified predictors, was found to significantly increase connection to nature when compared to walking in nature alone or walking in and engaging with the built environment. The findings indicate that contact, emotion, meaning, compassion, and beauty are pathways for improving nature connectedness. The pathways also provide alternative values and frames to the traditional knowledge and identification routes often used by organisations when engaging the public with nature.N/

    High Refractive Index Silicone Gels for Simultaneous Total Internal Reflection Fluorescence and Traction Force Microscopy of Adherent Cells

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    Substrate rigidity profoundly impacts cellular behaviors such as migration, gene expression, and cell fate. Total Internal Reflection Fluorescence (TIRF) microscopy enables selective visualization of the dynamics of substrate adhesions, vesicle trafficking, and biochemical signaling at the cell-substrate interface. Here we apply high-refractive-index silicone gels to perform TIRF microscopy on substrates with a wide range of physiological elastic moduli and simultaneously measure traction forces exerted by cells on the substrate

    Report on identification of keystone species and processes across regional seas. DEVOTES FP7 Project

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    WP6, Deliverable 6.1, DEVOTES ProjectIn managing for marine biodiversity, it is worth recognising that, whilst every species contributes to biodiversity, each contribution is not of equal importance. Some have important effects and interactions, both primary and secondary, on other components in the community and therefore by their presence or absence directly affect the biodiversity of the community as a whole. Keystone species have been defined as species that have a disproportionate effect on their environment relative to their abundance. As such, keystone species might be of particular relevance for the marine biodiversity characterisation within the assessment of Good Environmental Status (GEnS), for the Marine Strategy Framework Directive (MSFD).The DEVOTES Keystone Catalogue and associated deliverable document is a review of potential keystone species of the different European marine habitats. The catalogue has 844 individual entries, which includes 210 distinct species and 19 groups classified by major habitat in the Baltic Sea, North East Atlantic, Mediterranean, Black Sea (EU Regional Seas) and Norwegian Sea (Non-­‐EU Sea). The catalogue and the report make use/cite 164 and 204 sources respectively. The keystones in the catalogue are indicated by models, by use as indicators, by published work (e.g. on traits and interactions with other species), and by expert opinion based on understanding of systems and roles of species/groups. A total of 74 species were considered to act as keystone predators, 79 as keystone engineers, 66 as keystone habitat forming species, while a few were thought of having multiple roles in their marine ecosystems. Benthic invertebrates accounted for 50% of the reported keystone species/groups, while macroalgae contributed 17% and fish12%. Angiosperms were consistently put forward as keystone habitat forming and engineering species in all areas. A significant number of keystones were invasive alien species.Only one keystone, the bivalve Mya arenaria, was common to all four EU regional seas. The Mediterranean Sea had the largest number of potential keystones (56% of the entries) with the least in the Norwegian Sea. There were very few keystones in deep waters (Bathyal-­‐Abyssal, 200+ m), with most reported in sublittoral shallow and shelf seabeds or for pelagic species in marine waters with few in reduced/variable salinity waters. The gaps in coverage and expertise in the catalogue are analysed at the habitat and sea level, within the MSFD biodiversity component groups and in light of knowledge and outputs from ecosystem models (Ecopath with Ecosim).The understanding of keystones is discussed as to when a species may be a dominant or keystone with respect to the definition term concerning ‘disproportionate abundance’, how important are the ‘disproportionate effects’ in relation to habitat formers and engineers, what separates a key predator and key prey for mid-­‐trophic range species and how context dependency makes a species a keystone. Keystone alien invasive species are reviewed and the use of keystone species model outputs investigated. In the penultimate sections of the review the current level of protection on keystone species and the possibilities for a keystone operational metric and their use in management and in GEnS assessments for the MSFD are discussed. The final section highlights the one keystone species and its interactions not covered in the catalogue but with the greatest impact on almost all marine ecosystems, Homo sapiens
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