Climate variability and Crater Lake water levels

Crater Lake has fluctuated in elevation by 5 meters during the 20th Century. Reasons for these fluctuations were investigated as part of a long-term study of the Crater Lake ecosystem. Lake level changes were found to be closely related to precipitation variations. The lake can be thought of as acting as both a giant precipitation gage and as a large evaporation "pan". Winter snowfall variations are related to variations in the Southern Oscillation Index. Crater Lake offers a unique combination of simple geometry and hydrology, and a long record of supporting data, available nowhere else in the world for a caldera lake.

Effect of decapsulation on viability and hatching performance of Artemia cysts at different salinity levels

Artemia cysts were produced from the traditional solar salt works of Bangladesh through different fertilization treatments were tested for viability and hatching performance in different forms, such as processed and preserved, processed and decapsulated and unprocessed and undecapsulated. Decapsulated cysts performed maximum hatching (86.0%) in 20ppt salinity during 48 hours of incubation. The hatching percentage by the unprocessed and undecapsulated cysts were very low (12.0- 18.7%) in all the tested salinity grades.

Effects of culture treatments on HUFA levels in Artemia cysts

Artemia cysts (of GSL, Utah, USA origin) were produced from the modified traditional solar salt works of Bangladesh during winter months through different feeding/fertilization treatments (T1, T2, T3, T4 ) were analyzed to understand the effects of treatments on their fatty acid profile. Palmitic, Linolenic, Eicosapantaenonic and Docohexaenoic acids (mg/g. DW) were found highest for the cysts in T1 (16.0% ±1 .36), T2 (14.7% ±0.47), T3 (4.7% ±0.40) and T4 (0.7% ±0.06) treatments, respectively. High amount of 18:3(n-3) acids in the cysts of all sources proves to be freshwater type of the cysts. The presence of marine type essential fatty acids in the cysts of all sources were found low for 20:5n-3 (3.7-4.7%) and very low for 22:6n-3 (0.09-0.7%). No significant variation was observed for 16:0 acids within the treatments, but for 18:3(n-3) acid, the variation was found highly significant (P= 0.0052) between T2 and T4 treatments. For 20:5(n-3), only variation between T2 and T4 was found insignificant (P=0.1161), but between other treatments, significant variation was observed between T2 and T4 (P=0.0241), T2 and T4 (P=0.0022) and T1 andT4 (P=0.0161). No significant variation was found in other treatments.

Effect of feeding three different formulated feeds having different protein levels on the growth of angel fish (Pterophyllum scalare) juveniles

Experiment was conducted to study the effect of dietary protein level on growth and nutrient utilization by angel fish (Pterophyllum scalare) juveniles. Fifty-four juveniles (average wt. 2-2.5 g) were equally divided in three treatments with each of three replicates. Three formulated diets with graded protein levels, T1 (35% CP), T2 (40% CP) and T3 (45% CP) were fed to juveniles for 45 days. A trend of higher weight gain %, SGR, FER and PER was found with the increased CP level in the feed. Feed intake was similar in all the groups. T3 group fed with 45% CP registered highest weight gain % (43.26 ± 2.07), SGR (0.78 ± 0.04), FER (0.29 ± 0.01), which were significantly higher (P<0.05) than the T1 and T2 groups. Protein digestibility of T2 and T3 groups was significantly higher than the T1 group. Survival was similar in all the experimental groups. Diet with 45% CP with protein energy ratio of 112.62 mg protein/K cal. is ideal for juvenile angel fish for indoor rearing.

Effects of dietary phosphorus and zinc levels on growth artd bone mineralization in fingerlings of rainbow trout, Oncorhynchus mykiss

A laboratory based 2 x 2 factorial experiment was conducted to investigate the influences of dietary phosphorus and zinc levels on growth and bone mineralization in fingerlings of rainbow trout for 21 weeks. Two levels of phosphorus (19 and 30 mg/g) and two levels of zinc (55 and 103 Ag/g) in the dry diets were tested. Duplicate tanks of 30 rainbow trout (average weight 1.56 ± 0.24 g) per 60L glass tank were fed experimental diets three times a day to apparent satiation level at 15 to 24°C water temperature. The results of the present study demonstrated that dietary phosphorus supplementation influenced the growth and bone mineralization whereas zinc levels significantly (p<0.05) influenced bone mineralization in rainbow trout. Further investigations in this area with different size and age groups of this fish are broadly needed.

Effects of different dietary levels of vitamin E on the breeding performance of Heteropneustes fossilis (Bloch)

Experiments on the study of different dietary levels of vitamin E on the growth and breeding performance of Heteropneustes fossilis brood fish were carried out in two phases. The first phase consisted of studying its ovarian development and the second phase on breeding performance. Sixty female fishes were stocked in twelve experimental chambers of a raceway. The effects of four dietary vitamin E levels viz. 0 (served as control), 50, 100 and 200 mg/kg feed, on the somatic growth, ovarian development of brood fish and on their breeding performance were studied. Each treatment had three replications. It was observed that body growth in terms of length and weight was best with 0 mg vitamin E/kg feed and 200 mg vitamin E/kg of feed gave poorest result. The gonado-somatic index and fecundity, however, was highest in the fish fed with 100 mg vitamin E/kg of feed. In case of breeding performance such as ovulation rate, fertilization rate, hatching rate and survival rate, the best result was obtained with 200 mg vitamin E/kg of feed. The overall result of this experiment indicates that 200 mg vitamin E/kg of feed is the best vitamin E dose for H fossilis brood and vitamin E content has a positive impact on ovarian development.

Influence of formulated diets with varying protein levels on growth and ammonia excretion in the fry of Indian major carp, Cirrhina mrigala

The influence of formulated isocaloric diets of different protein levels (30, 35, 40, 45 and 50%) on the growth and ammonia excretion of the Indian major carp Cirrhina mrigala fry was studied for a rearing period of four weeks in the laboratory. Fishmeal, groundnut oilcake and silkworm pupae formed the source of protein in all the diets. As the dietary protein level increased from 30 to 40%, the growth and conversion efficiency increased significantly. Further increase in the protein level resulted in decrease in growth and conversion efficiency. Growth rate, weight gain (%), and gross and net feed conversion efficiencies were maximum at 40% dietary protein level. Ammonia excretion was directly proportional to the level of protein in the diet.

Modelling the evolution of uncertainty levels during design

Design work involves uncertainty that arises from, and influences, the progressive development of solutions. This paper analyses the influences of evolving uncertainty levels on the design process. We focus on uncertainties associated with choosing the values of design parameters, and do not consider in detail the issues that arise when parameters must first be identified. Aspects of uncertainty and its evolution are discussed, and a new task-based model is introduced to describe process behaviour in terms of changing uncertainty levels. The model is applied to study two process configuration problems based on aircraft wing design: one using an analytical solution and one using Monte-Carlo simulation. The applications show that modelling uncertainty levels during design can help assess management policies, such as how many concepts should be considered during design and to what level of accuracy. © 2011 Springer-Verlag.