1,998 research outputs found

    A test of tau neutrino interactions with atmospheric neutrinos and K2K

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    The presence of a tau component in the flux of atmospheric neutrinos inside the Earth, due to flavor oscillations, makes these neutrinos a valuable probe of interactions of the tau neutrino with matter. We study -- analytically and numerically -- the effects of nonstandard interactions in the nu_e-nu_tau sector on atmospheric neutrino oscillations, and calculate the bounds on the exotic couplings that follow from combining the atmospheric neutrino and K2K data. We find very good agreement between numerical results and analytical predictions derived from the underlying oscillation physics. While improving on existing accelerator bounds, our bounds still allow couplings of the size comparable to the standard weak interaction. The inclusion of new interactions expands the allowed region of the vacuum oscillation parameters towards smaller mixing angles, 0.2 ~< sin^2 theta_{23} ~< 0.7, and slightly larger mass squared splitting, 1.5 * 10^{-3} eV^2 ~< |\Delta m^2_{23}| ~< 4.0 * 10^{-3} eV^2, compared to the standard case. The impact of the K2K data on all these results is significant; further important tests of the nu_e-nu_tau exotic couplings will come from neutrino beams experiments such as MINOS and long baseline projects.Comment: 8 figures, some typos corrected, minor editing in the reference

    Impact of the Sun on Remote Sensing of Sea Surface Salinity from Space

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    The sun is a sufficiently strong source of radiation at L-band to be an important source of interference for radiometers on future satellite missions such as SMOS, Aquarius, and Hydros designed to monitor soil moisture and sea surface salinity. Radiation from the sun can impact passive remote sensing systems in several ways, including line-of-sight radiation that comes directly from the sun and enters through antenna side lobes and radiation that is reflected from the surface to the radiometer. Examples are presented in the case of Aquarius, a pushbroom radiometer with three beams designed to monitor sea surface salinity. Near solar minimum, solar contamination is not a problem unless the sun enters near the main beam. But near solar maximum, contamination from the sun equivalent to a change of salinity on the order of 0.1 psu can occur even when the signal enters in sidelobes far from the main beam

    Application of remote sensing techniques for locating pelagic fish concentrations along the Kerala coast (SW coast of India) - work done and future prospects

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    Intensive validation programme on Potential Fishing Zone forecasts carried out by the MARSIS, Central Marine Fisheries Research Institute, Cochin, at 17 selectedjish landing centres along the Kerala coast between November 1995 and May 1996 revealed a positive relationship betwen PFZ and occurence/abundance of commercially important pelagic fishes. An attempt is made to identify possible reasons for the above, based on results of oceanographic itivestigations undertaken in the area and also taking into consideration fish behaviour in relation to environn-ieni based on past data. Future plans for evolving a suitable prediction system for commercially important pelagic fishes in the coastal waters of the mainland and skipjack fishery in the Lakshadweep islands based on PFZ forecasts are also discussed in view of its importance to the artisanal and small mechanised sector fishermen for reducing the searching time and thereby effecting an overall reduction in the cost of fishing

    Rare occurrence of Reinhardt’s cranch squid Liocranchia reinhardti (Cephalopod: Cranchiidae) from southeastern Arabian Sea

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    Single individual of the rare cranchiid squid Liocranchia reinhardti belonging to the Cranchiidae family was caught in a bottom trawl operated at 80 m in southeastern Arabian Sea. The morphometric measurements and indices of the specimen are provided. Statolith microstructure analysis revealed that the L. reinhardti with 118 mm dorsal mantle length (DML) had an age of 71 days with growth rate of 1.66 mm DML/day

    Checklist of marine bivalves and gastropods off Kollam, Kerala

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    Species diversity of any region can be illustrated by means of an available checklist. It provides an overview of the species that have been recorded. and can be considered to understand the local fauna. Fortnightly surveys were carried out to collect the shell-molluscs samples during 2012 - 2014 period from the by-catch of shrimp/fish trawlers landed at Sakthikulangara-Neendakara Fishing Harbour, Kollam. Collected bivalves and gastropods included both empty shells and living animals. Collected shells were brought to the laboratory and placed in freezer for 24 hours. This would liquefy the mollusc body and allowed easy extraction with a strong jet of water

    Closing the sea surface mixed layer temperature budget from in situ observations alone: Operation Advection during BoBBLE

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    Sea surface temperature (SST) is a fundamental driver of tropical weather systems such as monsoon rainfall and tropical cyclones. However, understanding of the factors that control SST variability is lacking, especially during the monsoons when in situ observations are sparse. Here we use a ground-breaking observational approach to determine the controls on the SST variability in the southern Bay of Bengal. We achieve this through the first full closure of the ocean mixed layer energy budget derived entirely from in situ observations during the Bay of Bengal Boundary Layer Experiment (BoBBLE). Locally measured horizontal advection and entrainment contribute more significantly than expected to SST evolution and thus oceanic variability during the observation period. These processes are poorly resolved by state-of-the-art climate models, which may contribute to poor representation of monsoon rainfall variability. The novel techniques presented here provide a blueprint for future observational experiments to quantify the mixed layer heat budget on longer time scales and to evaluate these processes in models

    Observation of the east-west anisotropy of the atmospheric neutrino flux

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    The east-west anisotropy, caused by the deflection of primary cosmic rays in the Earth's magnetic field, is observed for the first time in the flux of atmospheric neutrinos. Using a 45 kt-year exposure of the Super-Kamiokande detector, 552 e-like and 633 mu-like horizontally-going events are selected in the momentum range between 400 and 3000 MeV/c. The azimuthal distribution of e-like and mu-like events agrees with the expectation from atmospheric neutrino flux calculations that account for the geomagnetic field, verifying that the geomagnetic field effects in the production of atmospheric neutrinos in the GeV energy range are well understood.Comment: 8 pages,3 figures revtex, submitted to PR

    Western Indian Ocean marine and terrestrial records of climate variability: a review and new concepts on land-ocean interactions since AD 1660

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    We examine the relationship between three tropical and two subtropical western Indian Ocean coral oxygen isotope time series to surface air temperatures (SAT) and rainfall over India, tropical East Africa and southeast Africa. We review established relationships, provide new concepts with regard to distinct rainfall seasons, and mean annual temperatures. Tropical corals are coherent with SAT over western India and East Africa at interannual and multidecadal periodicities. The subtropical corals correlate with Southeast African SAT at periodicities of 16–30 years. The relationship between the coral records and land rainfall is more complex. Running correlations suggest varying strength of interannual teleconnections between the tropical coral oxygen isotope records and rainfall over equatorial East Africa. The relationship with rainfall over India changed in the 1970s. The subtropical oxygen isotope records are coherent with South African rainfall at interdecadal periodicities. Paleoclimatological reconstructions of land rainfall and SAT reveal that the inferred relationships generally hold during the last 350 years. Thus, the Indian Ocean corals prove invaluable for investigating land–ocean interactions during past centuries

    Calibration of Super-Kamiokande Using an Electron Linac

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    In order to calibrate the Super-Kamiokande experiment for solar neutrino measurements, a linear accelerator (LINAC) for electrons was installed at the detector. LINAC data were taken at various positions in the detector volume, tracking the detector response in the variables relevant to solar neutrino analysis. In particular, the absolute energy scale is now known with less than 1 percent uncertainty.Comment: 24 pages, 16 figures, Submitted to NIM
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