40 research outputs found

    Neutrino Telescopy in the Mediterranean Sea

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    The observation of high-energy extraterrestrial neutrinos is one of the most promising future options to increase our knowledge on non-thermal processes in the universe. Neutrinos are e.g. unavoidably produced in environments where high-energy hadrons collide; in particular this almost certainly must be true in the astrophysical accelerators of cosmic rays, which thus could be identified unambiguously by sky observations in "neutrino light". On the one hand, neutrinos are ideal messengers for astrophysical observations since they are not deflected by electromagnetic fields and interact so weakly that they are able to escape even from very dense production regions and traverse large distances in the universe without attenuation. On the other hand, their weak interaction poses a significant problem for detecting neutrinos. Huge target masses up to gigatons must be employed, requiring to instrument natural abundances of media such as sea water or antarctic ice. The first generation of such neutrino telescopes is taking data or will do so in the near future, while the second-generation projects with cubic-kilometre size is under construction or being prepared. This report focuses on status and prospects of current (ANTARES, NEMO, NESTOR) and future (KM3NeT) neutrino telescope projects in the Mediterranean Sea.Comment: Presented at 27th Int. School on Nucl. Phys. (Neutrinos in Cosmology, in Astro, Particle and Nuclear Physics), Erice/Italy, Sept. 2005; 8 pages, 7 figures. To appear in Prog. Part. Nucl. Phys. V2,V3: fixed incompatibilities of postscript figures with the arXiv softwar

    Earlier proteoglycan turnover promotes higher efficiency matrix remodeling in MRL/MpJ tendons

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    While most mammalian tissue regeneration is limited, the Murphy Roths Large (MRL/MpJ) mouse has been identified to regenerate several tissues, including tendon. Recent studies have indicated that this regenerative response is innate to the tendon tissue and not reliant on a systemic inflammatory response. Therefore, we hypothesized that MRL/MpJ mice may also exhibit a more robust homeostatic regulation of tendon structure in response to mechanical loading. To assess this, MRL/MpJ and C57BL/6J Flexor digitorum longus tendon explants were subjected to stress-deprived conditions in vitro for up to 14 days. Explant tendon health (metabolism, biosynthesis, and composition), matrix metalloproteinase activity, gene expression, and tendon biomechanics were assessed periodically. We found a more robust response to a loss of mechanical stimulus in the MRL/MpJ tendon explants, exhibiting an increase in collagen production and MMP activity consistent with previous in vivo studies. This greater collagen turnover was preceded by an early expression of small leucine rich proteoglycans and proteoglycan-degrading MMP-3, promoting efficient regulation and organization of newly synthesized collagen and allowing for more efficient overall turnover in MRL/MpJ tendons. Therefore, mechanisms of MRL/MpJ matrix homeostasis may be fundamentally different from that of B6 tendons and may indicate better recovery from mechanical microdamage in MRL/MpJ tendons. We demonstrate here the utility of the MRL/MpJ model in elucidating mechanisms of efficient matrix turnover and its potential to shed light on new targets for more effective treatments for degenerative matrix changes brought about by injury, disease, or aging. This article is protected by copyright. All rights reserved.NIH/National Institutes of Healt

    Probing a Supersymmetric Model for Neutrino Masses at Ultrahigh Energy Neutrino Telescopes

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    A bilinear R-Parity breaking SUSY model for neutrino mass and mixing predicts the lightest superparticle to decay mainly into a pair of tau leptons or b quarks along with a neutrino for relatively light SUSY spectra. This leads to a distinctive triple bang signature of SUSY events at ultrahigh energy neutrino telescopes like IceCube or Antares. While the expected signal size is only marginal at IceCube, it will be promising for a future multi-km^3 size neutrino telescope.Comment: 11 pages pdf including 2 figures. Discussion added. Final version to appear in Physics Letters
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