605 research outputs found

    Realization of a spontaneous gauge and supersymmetry breaking vacuum

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    It is one of the major issues to realize a vacuum which breaks supersymmetry (SUSY) and R-symmetry, in a supersymmetric model. We study the model, where the same sector breaks the gauge symmetry and SUSY. In general, the SUSY breaking model without gauge symmetry has a flat direction at the minimum of F-term scalar potential. When we introduce U(1) gauge symmetry to such a SUSY breaking model, there can appear a runaway direction. Such a runway direction can be lifted by loop effects, and the gauge symmetry breaking and SUSY breaking are realized. The R-symmetry, that is assigned to break SUSY, is also spontaneously broken at the vacuum. This scenario can be extended to non-Abelian gauge theories. We also discuss application to the Pati-Salam model and the SU(5) grand unified theory. We see that non-vanishing gaugino masses are radiatively generated by the R-symmetry breaking and the gauge messenger contribution.Comment: 23 pages, version accepted in JHE

    Weight-based yield per recruitment and spawning-biomass per recruitment analyses of Pacific cod Gadus macrocephalus off the Pacific coast of southern Hokkaido, Japan

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    The present study assessed the stock state of Pacific cod Gadus macrocephalus caught off the coast of southern Hokkaido, Japan. Weight-based yield per recruitment (YPR) and spawning-biomass per recruitment (SPR) analyses were used for this assessment. The current fishing mortality (average from 1998 to 2000) was 0.65 and weight at first capture was 0.5 kg bodyweight. Under these fishing pressures, the YPR of Pacific cod in southern Hokkaido was 1.06 kg/recruitment and percentage of SPR (%SPR) was 6.9%. The %SPR was lower than the critical limit at 20%SPR. The main reason that values of both YPR and %SPR were not optimum, would be that the weight at first capture was too small. Raising the weight at first capture was thought to be a better strategy from the biological viewpoint, and reducing fishing mortality to 0.3 would be the next alternative strategy from the fisheries management viewpoint

    Visible and near-infrared reflectance spectroscopy of the Yamato 980459 meteorite in comparison with some shergottites

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    Visible and near-infrared reflectance spectrum of a sample of Yamato (Y) 980459 meteorite has been measured. Preliminary analyses of the spectrum have been performed using the modified Gaussian model, and the results have been compared with those of similar analyses of some shergottites and tricomponent mixtures of olivine, pyroxene, and plagioclase. They suggest that Y980459 has lower Fe and/or Ca concentration in pyroxene phase except its high-Ca pyroxene having similar Fe/Ca concentration to EETA79001 (Lithology A), lower pyroxene abundance, and more glassy phase than those shergottite samples. An estimated pyroxene modal abundance of this Y980459 sample is 36±13%, which is consistent with another estimate of 48% by an independent petrographic study

    Reflectance spectra of the Yamato 000593 nakhlite: Spectroscopic similarities to other nakhlites

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    Y000593 (Y) is a newly found nakhlite and its component minerals are augite (~80 vol% ), olivine (~10 vol% ) and mesostasis (~10 vol% ). We compare the reflectance spectrum of Y000593 with those of two other nakhlites, Nakhla and Lafayette. The reflectance spectrum of Y000593 is similar to that of Nakhla, and is also similar to Lafayette except for differences in slope from 0.6-0.8μm in wavelength. Reflectance spectra of all these nakhlites show two strong absorption bands around 1μm and 2μm due to augite. Their band minimum wavelengths were calculated using the polynomial fitting and the modified Gaussian model (MGM). Almost all of their band centers and band parameters were similar to one another, which is consistent with the mineralogical and petrological study of nakhlites

    Gastropod shell as a substrate for cocoon deposition by the deep-sea fish leech Notostomum cyclostomum (Hirudinida: Piscicolidae)

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    Cocoons of the piscicolid leech Notostomum cyclostomum Johansson, 1898 were found on the shell of the whelk Buccinum striatissimum collected at 200 m in depth in the southern Sea of Japan off Hyogo Prefecture, central Japan. The leech appears to utilize whelks as well as snow crabs Chionoecetes opilio as a substrate for cocoon deposition

    Notostomum cyclostomum (Hirudinida: Piscicolidae) parasitic on a flathead flounder, Hippoglossoides dubius (Pleuronectidae), in the southern Sea of Japan off western Japan

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    A specimen of the piscicolid leech Notostomum cyclostomum Johansson, 1898 was collected from the eyed body surface of a flathead flounder, Hippoglossoides dubius Schmidt, 1904, caught at 232 m deep in the southern Sea of Japan west off the Oki Islands, Shimane Prefecture, western Japan. This represents the first Japanese record for fish infestation by N. cyclostomum. Hippoglossoides dubius is a new host of N. cyclostomum
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