Effect of analytical conditions in wavelength dispersive electron microprobe analysis on the measurement of strontium-to-calcium (Sr/Ca) ratios in otoliths of anadromous salmonids

The use of strontium-to-calcium (Sr/Ca) ratios in otoliths is becoming a standard method to describe life history type and the chronology of migrations between freshwater and seawater habitats in teleosts (e.g. Kalish, 1990; Radtke et al., 1990; Secor, 1992; Rieman et al., 1994; Radtke, 1995; Limburg, 1995; Tzeng et al. 1997; Volk et al., 2000; Zimmerman, 2000; Zimmerman and Reeves, 2000, 2002). This method provides critical information concerning the relationship and ecology of species exhibiting phenotypic variation in migratory behavior (Kalish, 1990; Secor, 1999). Methods and procedures, however, vary among laboratories because a standard method or protocol for measurement of Sr in otoliths does not exist. In this note, we examine the variations in analytical conditions in an effort to increase precision of Sr/Ca measurements. From these findings we argue that precision can be maximized with higher beam current (although there is specimen damage) than previously recommended by Gunn et al. (1992).

Current water supply conditions in California

This paper contains a brief report on the status of the California water supply situation on March 1, 1989, including a review of the antecedent conditions of the past two dry water years.

California water conditions in 1995

From 1987 through 1992, California endured 6 consecutive years of drought for the second time this century. The drought was broken in most parts of the state by a wet year in 1993, in which runoff was 125 percent of average. But 1994 was again critically dry, with runoff only 40 percent of average statewide, raising fears that the drought had resumed. The "drought watch" of 1994 was finally washed out to sea by two large floods (January and March), which made 1995 one of the wettest years this century and refilled all but a couple of California's major reservoirs. This paper provides information on water conditions and flooding in 1995 and some comparisons with previous years.

Comparisons of open boundary conditions in a barotropic model of the northern Arabian Sea

These simulations are focused on the sensitivity of the barotropic ocean non-linear model to the various open boundary conditions (OBCs). Different OBCs from gradient to radiation condition are examined to determine the best result and help to choose the most appropriate OBCs. Since the interior points are changing with time both implicit and explicit forms are applied. The simulations showed that the interior flow is sensitive to changes in the OBCs and the results are highly dependent on the bathymetry of the area. When a constant depth (100m) is used, the circulation pattern with all OBCs is same. The best boundary conditions are Orlanski Radiation and its modified form. These boundary conditions produce identical adjustment in velocity and are determined to be satisfactory for both constant depth and actual bathymetry.

Studies on technological problems associated with the processing of cooked frozen prawns. Pt. 2. Hygienic conditions in relation to bacteriological characteristics

The importance of sanitary practices in the processing of precooked frozen shrimps has been discussed. Several typical examples have been shown to point out the different sources of contamination of the product and the extent to which each of the factors by itself or in combination affect the bacterial quality of the final product. A scheme of processing has also been suggested for controlling the microbial quality.

Benthic diversity of River Gomti in relation to the prevailing environmental conditions in Lucknow

To evaluate the benthic diversity of River Gomti in relation to the prevailing environmental conditions, four stations, viz., Maa Chandrika Devi, Daliganj, Ambedkar Park and Aquaduct, were identified from upstream to downstream along the course of the river in Lucknow. Dissolved oxygen was low on many occasions at all the stations except Maa Chandrika Devi and chemical oxygen demand values were high. There was a gradual increase in mean nitrite and phosphate values from up to downstream. Benthic fauna was dominated by oligochaetes and chironomus larvae. Other groups reported were leeches, nematodes, sponges, crustaceans, pelycypodes, gastropods and fish fry. Population density was exceptionally high at Daliganj (20,135 m sub(-1) ) followed by Ambedkar Park (5,199 m sub(-1)) and Aquaduct (3,287 m sub(-1)), and low at Maa Chandrika Devi (264 m sub(-1)). Oligochaete genera common at all the four stations were Lumbricillus, Limnodrillus, Branchiura, Chaetogaster, Nais and Tubifex. Odonates were reported only from Maa Chandrika Devi while sponges were encountered at Daliganj and Aquaduct. On some occasions, fish fry were also found at Ambedkar Park and Aquaduct. Seasonally, maxima for population density were observed during pre-monsoon and minima during monsoon. The organic pollution indicator benthic species reported were tubificids, chironomids, culicoid larvae, Lamellidens sp., Corbicula sp., Lymnaea sp. and leech. Branchiurans, Tubifex sp. and Chironomus larvae were reported at all the stations. Filthy condition with foul smell throughout the length of the river coupled with poor water quality and appearance of indicator organisms at all the stations indicate that the river is under severe pollution stress due to anthropogenic discharges and it has reached an alarming stage.

Evaluation of milkfish (Chanos chanos Forskal) and prawn (Penaeus monodon Fabricius) in polyculture systems

The growth, survival and profitability of C. chanos and P. monodon grown in 5 different combinations for 100 days in 500m2 brackish water ponds were assessed. Differences in the growth and production of prawns cultured singly or in combination with milkfish at increasing stocking density strongly suggests that the presence of milkfish exerts some negative effect on prawn. However, growth production and competition index data suggest that the presence of prawn do not significantly affect milkfish. While the maximum production of prawn can be attained in monoculture, its polyculture with 2000 milkfish/ha is also economically feasible.

Synchronization in baroclinic systems

Synchronization of periodic and chaotic oscillations between two coupled rotating baroclinic fluid systems will be presented. The numerical part of the study involves a pair of coupled two-layer quasigeostrophic models, and the experimental part comprises two thermally coupled baroclinic fluid annuli, rotating one above the other on the same turntable. Phase synchronization and imperfect synchronization (phase slips) have been found in both model and experiments, and model simulations also exhibit chaos-destroying synchronization. © 2008 IOP Publishing Ltd.