TERMITE FAUNA OF KRAKATAU AND ASSOCIATED ISLANDS, SUNDA STRAITS, INDONESIA

Frequent volcanic eruptions, submergence and emergence of some of theIndonesian islands has made them ail object of intense biogeographical significance. These geological catastrophies resulted in complete sterilization of the area biologically, wiping out all forms of life. Subsequent reuegetation and establishment of new fauna attracted many scientists, some of them having made very significant contributions.The present contribution deals with termite fauna of Krakatau and associated islands. In all, twenty five species and 13 genera, the highest number so far reported, from Carita (9 species), Panaitan Islands (6 species), Rahota Besar (2 species), Anak Krakatau and Sertung (1 species each) have been recorded in this publication. Of these, while, Prorhinotermes panaitanensis is new to science, two species (Glyptotermes besarensis and G. panaitanensis) have been described recently by the senior author (MLT). Similarly Glyptotermes minutus, Nasutitermes culasiensis and Hospitalitermes buzpnensis have been recorded for the first time from the Indonesia. Several other species are new distributional records. Nasutitermes matagensis matagensiformisand Schedorhinotermes javanicus are the most successfully colonizedspecies, recorded almost in all the islands under reference.Besides the taxonomic treatment of the fauna, the paper also gives key to genera based on soldier caste

Diurnal variations of plankton diversity and physico-chemical characteristics of Rewalsar Wetland, Himachal Pradesh, India

The contemporary examination signifies diurnal variations in various physico-chemical parameters of Rewalsar wetland during summer and winter. Fluctuations in the intensity and duration of solar radiations, temperature, photosynthesis, respiration and decomposition were the major factor responsible for diel fluctuations in the physico-chemical factors. Water temperature showed increment from 24.82°C to 29.20°C in June and from 9.15°C to 12.95°C in January. Minimum and maximum values of temperature were recorded at 06.30 hrs and 14.30 hrs respectively. Secchi disc transparency was low in the wetland due to abundance of phytoplankton. It ranged from 0.00-121.00 cm during summer and 0.00-131.00 cm during winter. Oxygen percentage saturation values were minimum (summer 26% and in winter 58%) in the morning at 06.30 hrs and reached maximum (70% in summer and 100% in winter) in the afternoon at 14.30 hrs. Free carbon dioxide was present only at 06.30 a.m. in winter. The pH of water remained alkaline and increased from 10.30 hrs to 14.30 hrs, thereafter it decreased again. Carbonates were present only in January (0.00-5.80 mg L–1). Bicarbonates were 132.52-152.50 mg L–1 in June and 92.35-121.23 mg L–1 in January. The values for chloride, hardness and electrical conductance were higher during summer as compared to winter. Total hardness showed fluctuations from 163.45 to 181.24 mg L–1 in summer and 121.45 to 140.72 mg L–1 in winter, chloride. Phytoplankton were composed of members of Bacillariophyceae, Chlorophyceae, Cyanophyceae, Euglenophyceae and Cryptophyceae. Phytoplankton showed up movements during day time and down movement after sunset. Zooplankton were composed of Rotifera, Cladocera and Copepoda. They showed up migration during night hours and down migration during day

Exchange bias effect in the phase separated Nd_{1-x}Sr_{x}CoO_3 at the spontaneous ferromagnetic/ferrimagnetic interface

We report the new results of exchange bias effect in Nd_{1-x}Sr_{x}CoO_3 for x = 0.20 and 0.40, where the exchange bias phenomenon is involved with the ferrimagnetic (FI) state in a spontaneously phase separated system. The zero-field cooled magnetization exhibits the FI (T_{FI}) and ferromagnetic (T_C) transitions at ~ 23 and \sim 70 K, respectively for x = 0.20. The negative horizontal and positive vertical shifts of the magnetic hysteresis loops are observed when the system is cooled through T_{FI} in presence of a positive static magnetic field. Training effect is observed for x = 0.20, which could be interpreted by a spin configurational relaxation model. The unidirectional shifts of the hysteresis loops as a function of temperature exhibit the absence of exchange bias above T_{FI} for x = 0.20. The analysis of the cooling field dependence of exchange bias field and magnetization indicates that the ferromagnetic (FM) clusters consist of single magnetic domain with average size around \sim 20 and ~ 40 \AA ~ for x = 0.20 and 0.40, respectively. The sizes of the FM clusters are close to the percolation threshold for x = 0.20, which grow and coalesce to form the bigger size for x = 0.40 resulting in a weak exchange bias effect.Comment: 9 pages, 9 figure