92 research outputs found

    Solutions of the atmospheric, solar and LSND neutrino anomalies from TeV scale quark-lepton unification

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    There is a unique SU(4)SU(2)LSU(2)RSU(4) \otimes SU(2)_L \otimes SU(2)_R gauge model which allows quarks and leptons to be unified at the TeV scale. It is already known that the neutrino masses arise radiatively in the model and are naturally light. We study the atmospheric, solar and LSND neutrino anomalies within the framework of this model.Comment: Minor changes, 31 page

    Tabulated data from the SAS-2 high energy gamma ray telescope

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    The second small astronomy satellite (SAS-2) carried a high energy gamma ray telescope into an equitorial orbit with a 2 D inclination, an apogee of 610 km, and a perigee of 440 km. The energy threshold of the instrument was about 30 MeV, the energy of the gamma rays could be measured up to about 200 MeV, and the integral intensity above 200 MeV could also be measured. Summary tables of the gamma ray data are presented in two energy bands, 35-100 MeV and 100 MeV. The sky was divided into 144 solid angle elements, and, in each solid angle element for which data exist, the number of gamma rays observed is given and also the exposure factor. Information is provided to permit conversion of these data into approximate intensities

    Spaceflight results in increase of thick filament but not thin filament proteins in the paramyosin mutant of Caenorhabditis elegans

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    We have investigated the effect of microgravity during spaceflight on body-wall muscle fiber size and muscle proteins in the paramyosin mutant of Caenorhabditis elegans. Both mutant and wild-type strains were subjected to 10 days of microgravity during spaceflight and compared to ground control groups. No significant change in muscle fiber size or quantity of the protein was observed in wild-type worms; where as atrophy of body-wall muscle and an increase in thick filament proteins were observed in the paramyosin mutant unc-15(e73) animals after spaceflight. We conclude that the mutant with abnormal muscle responded to microgravity by increasing the total amount of muscle protein in order to compensate for the loss of muscle function

    Simvastatin suppresses the differentiation of C2C12 myoblast cells via a Rac pathway.

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    Statins, which are known as cholesterol-lowering drugs, have several additional effects including the enhancement of bone formation and the stimulation of smooth muscle cell proliferation. In this study, we investigated the signal pathway of simvastatin operating in C2C12 myoblast cells. Myotube formation of C2C12 cells was efficiently blocked by 1 muM simvastatin, and mevalonic acid was able to cancel this effect. Geranylgeranyl pyrophosphate restored the myotube formation, whereas farnesyl pyrophosphate did not. These findings demonstrate that the Rho family, such as Rho, Rac and Cdc42, occurring downstream of geranylgeranyl pyrophosphate in the mevalonic acid pathway, was involved in the simvastatin-mediated blockage of myotube formation. An inhibitor of Rho kinase did not influence the myotube formation; whereas an inhibitor of Rac blocked this process. Taken together, we conclude that the differentiation of C2C12 cells into myotubes was blocked by simvastatin through the pathway mediated by Rac, not by Rho

    Southern Ocean carbon sink enhanced by sea-ice feedbacks at the Antarctic Cold Reversal

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    The Southern Ocean occupies some 14% of the planet’s surface and plays a fundamental role in the global carbon cycle and climate. It provides a direct connection to the deep ocean carbon reservoir through biogeochemical processes that include surface primary productivity, remineralisation at depth, and the upwelling of carbon-rich water masses. However, the role of these different processes in modulating past and future air-sea carbon flux remains poorly understood. A key period in this regard is the Antarctic Cold Reversal (ACR, 14.6-12.7 kyr BP), a period of mid- to high-latitude cooling that coincided with a sustained plateau in deglacial atmospheric rise in CO2 globally. Here we reconstruct high-latitude Southern Ocean surface productivity from marine derived aerosols captured in a highly-resolved horizontal ice core. Our multiproxy reconstruction reveals a coherent signal of enhanced productivity across the ACR. Transient climate modelling indicates this period coincided with maximum seasonal variability in sea-ice extent, implying that sea-ice biological feedbacks enhanced CO2 sequestration, creating a significant regional marine carbon sink that contributed to the sustained plateau in CO2 at the ACR. Our results highlights the role Antarctic sea ice plays in controlling global CO2, and demonstrates the need to incorporate such feedbacks in climate-carbon models

    A Middle Palaeolithic wooden digging stick from Aranbaltza III, Spain

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    Aranbaltza is an archaeological complex formed by at least three open-air sites. Between 2014 and 2015 a test excavation carried out in Aranbaltza III revealed the presence of a sand and clay sedimentary sequence formed in floodplain environments, within which six sedimentary units have been identified. This sequence was formed between 137±50 ka, and includes several archaeological horizons, attesting to the long-term presence of Neanderthal communities in this area. One of these horizons, corresponding with Unit 4, yielded two wooden tools. One of these tools is a beveled pointed tool that was shaped through a complex operational sequence involving branch shaping, bark peeling, twig removal, shaping, polishing, thermal exposition and chopping. A use-wear analysis of the tool shows it to have traces related with digging soil so it has been interpreted as representing a digging stick. This is the first time such a tool has been identified in a European Late Middle Palaeolithic context; it also represents one of the first well-preserved Middle Palaeolithic wooden tool found in southern Europe. This artefact represents one of the few examples available of wooden tool preservation for the European Palaeolithic, allowing us to further explore the role wooden technologies played in Neanderthal communities
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