First records of dendrobranchiate prawns (Decapoda: Dendrobranchiata) from the Andaman Sea,India

ABSTRACT

The Andaman Sea adjoining the Indian Territory is biologically rich in terms of marine diversity. However, inadequate surveys during the post-independence era have resulted in large lacunae in data on the species composition in these waters. In this paper, we report the first observation of two species of dendrobranchiate prawns, Metapenaeopsis difficilis Crosnier, 1991 and Haliporus taprobanensis Alcock and Anderson, 1899, in the Indian seas, supplemented with notes on their morphological diagnoses, comparison with closely related species and zoogeographical distribution. Crustacean specimens were collected using trawl nets and a naturalists’ dredge on board the Fisheries Oceanography Research Vessel Sagar Sampada in the deeper offshore region between 124 and 850 m depth in the Andaman Sea during the period 2015–2017. Metapenaeopsis difficilis is distinguished by an oval-shaped thelycal plate and a low, unarmed bead-like plate on the thoracic sternum between the third pereiopods. Metapenaeopsis difficilis is previously reported from the Philippines, Indonesia, Coral Sea, New Caledonia, Marquesas Islands, and Wallis and Futuna Islands at depths between 21 and 440 m, thereby indicating its westward range extension. Haliporus taprobanensis is distinguished by a tough integument, presence of a postero-dorsal spine on the fourth pleonal somite, and smooth dorsum of the first four pleonal somites. Haliporus taprobanensis is previously reported from South Africa, Madagascar, off Sri Lanka, Indonesia, Philippines and northern Australia at depths between 300 and 1650 m.     

建设计算机实验教学中心培养应用型人才

根据计算机应用型人才培养的特点和实践教学的要求,整合现有的实践教学资源,按照分层次、重特色建设思路,以持续不断的实验教学改革为动力,建成了四川省实验教学示范中心.文章总结了近几年实验教学示范中心建设的实践探索经验,包括开放平台建设、特色实验室建设、实验教学体系及实验教学内容建设、实验室开放内涵深化等.     

'Magic' nucleus 42Si

Nuclear shell structures--the distribution of the quantum states of individual protons and neutrons--provide one of our most important guides for understanding the stability of atomic nuclei. Nuclei with 'magic numbers' of protons and/or neutrons (corresponding to closed shells of strongly bound nucleons) are particularly stable. Whether the major shell closures and magic numbers change in very neutron-rich nuclei (potentially causing shape deformations) is a fundamental, and at present open, question. A unique opportunity to study these shell effects is offered by the 42Si nucleus, which has 28 neutrons--a magic number in stable nuclei--and 14 protons. This nucleus has a 12-neutron excess over the heaviest stable silicon nuclide, and has only one neutron fewer than the heaviest silicon nuclide observed so far. Here we report measurements of 42Si and two neighbouring nuclei using a technique involving one- and two-nucleon knockout from beams of exotic nuclei. We present strong evidence for a well-developed proton subshell closure at Z = 14 (14 protons), the near degeneracy of two different (s(1/2) and d(3/2)) proton orbits in the vicinity of 42Si, and a nearly spherical shape for 42Si.