32 research outputs found

    Population structure of the grapsid crab, Helice tridens latimera (PARISI) in the Taiho mangrove, Okinawa, Japan

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    Grapsid crab Helice tridens latimera inhabiting mangroves, seashores as well as muddy and rocky areas. Ovigerous females were observed from December to May. Juveniles appeared in July and from December to April. In the laboratory they reached 9.50 mm in carapace width 4 months after hatching. It is likely that spawning of this crab occurs throughout the year

    Larval development of a semi terrestrial mangrove sesarmine crab Chasmagnathus convexus (Crustacea: Decapoda: Brachyura: Grapsidae) reared in laboratory

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    Four zoeal stages and one megalopal stage were identified in laboratory reared semiterrestrial mangrove sesarmine crab Chasmagnathus convexus. At an average salinity and temperature of 20±1% and 19.2±0.2°C, the megalopa was attained 24 days after hatching. Morphologically, the first zoae of C. convexz1s is very similar to those of other species of the genus Chasmagnathus as well as species of the genus Helice, in that view all share the following characteristics: lateral spine on the carapace, three pairs of setae on the posterior margin of the telson furca, one plus five setae on the endopod of the maxillule, and two plus two setae on the endopod of the maxilla. The differences between the first zoea and megalopa of and those of its congeners are discussed

    Proof-of-principle experiment for laser-driven cold neutron source

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    The scientific and technical advances continue to support novel discoveries by allowing scientists to acquire new insights into the structure and properties of matter using new tools and sources. Notably, neutrons are among the most valuable sources in providing such a capability. At the Institute of Laser Engineering, Osaka, the first steps are taken towards the development of a table-top laser-driven neutron source, capable of producing a wide range of energies with high brightness and temporal resolution. By employing a pure hydrogen moderator, maintained at cryogenic temperature, a cold neutron (25 meV\le 25\hbox { meV}≤25meV) flux of 2×103 n/cm2\sim 2\times 10^3\hbox { n/cm}^2∼2×103n/cm2/pulse was measured at the proximity of the moderator exit surface. The beam duration of hundreds of ns to tens of \upmu \hbox {s}μsis evaluated for neutron energies ranging from 100s keV down to meV via Monte-Carlo techniques. Presently, with the upcoming J-EPoCH high repetition rate laser at Osaka University, a cold neutron flux in orders of 1×109 n/cm2/s\sim 1\times 10^{9}\hbox { n/cm}^2/\hbox {s}∼1×109n/cm2/sis expected to be delivered at the moderator in a compact beamline

    Atyid shrimps (Crustacea: Decapoda: Caridea) of the Ryukyu Islands, southern Japan, with descriptions of two new species

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    10.1080/00222930601084049Journal of Natural History4038-402123-2172JNAH

    On the species of Japanese atyid shrimps (Decapoda: Caridea) described by William Stimpson (1860)

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    10.1651/C-2572.1Journal of Crustacean Biology263392-419JCBI
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