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  • 1
    Electronic Resource
    Electronic Resource
    Quasiclassical green function in an external field and small-angle scattering processes (2000)
    Springer
    Journal of experimental and theoretical physics 90 (2000), S. 66-78 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A representation is obtained for the quasiclassical Green functions of the Dirac and Klein-Gordon equations allowing for the first nonvanishing correction in an arbitrary localized potential which generally possesses no spherical symmetry. This is used to obtain a solution of these equations in an approximation similar to the Furry-Sommerfeld-Maue approximation. It is shown that the quasiclassical Green function does not reduce to the Green function obtained in the eikonal approximation and has a wider range of validity. This is illustrated by calculating the amplitude of small-angle scattering of a charged particle and the amplitude of Delbrück forward scattering. A correction proportional to the scattering angle was obtained for the amplitude of charged particle scattering in a potential possessing no spherical symmetry. The real part of the Delbrück forward scattering amplitude was calculated in a screened Coulomb potential.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.559095
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  • 2
    Electronic Resource
    Electronic Resource
    Optimization of fertilization rate for maximizing periphyton production on artificial substrates and the implications for periphyton-based aquaculture (2001)
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 32 (2001), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The effects of four rates of application of fertilizer, with cow manure (3000 kg ha−1), urea (100 (kg ha−1) and triple super phosphate (TSP) (100 kg ha−1) (treatment F)), treatment F × 0.5 (treatment 0.5F), treatment F × 1.5 (treatment 1.5F) and treatment F × 2 (treatment 2F), on periphyton, plankton and water quality in tropical freshwater ponds were studied. The highest periphyton biomass in terms of dry matter (3.27 mg cm−2 substrate), ash-free dry matter (2.06 mg cm−2 substrate) and chlorophyll a (7.49 µg cm−2 substrate) developed in treatment 1.5F. The ash content of periphyton was lower in treatment 1.5F (38% of dry matter) than in other treatments (57–66% of dry matter). Total ammonia and chlorophyll a of water increased with fertilization rate. Treatment 1.5F (cow manure, urea and TSP at rates of 4500, 150 and 150 kg ha−1 respectively) appears to be the optimum, yielding high quantity and quality periphyton. By supplying a substrate area for periphyton equivalent to the pond surface, it was estimated that this level of fertilization could support a fish production of around 5000 kg ha−1 y−1, without recourse to supplementary food.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2109.2001.00613.x
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of adding the small fish punti (Puntius sophore Hamilton) and/or mola (Amblypharyngodon mola Hamilton) to a polyculture of large carp (2003)
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 34 (2003), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This experiment was carried out in the framework of a project to develop a viable fish polyculture technology under Bangladeshi conditions that allows simultaneous fish production of small indigenous species for farm families' consumption and of large carp species as a cash crop. The polyculture included the large carp rohu, catla and mirror carp as cash crop fish, and the small indigenous fish punti and mola as food for the small-scale household. Total large carp stocking density was 10 000 fish ha−1, at a species ratio 1:1:1. Total small fish stocking densities were 0, 25 000 or 50 000 fish ha−1. The objectives were to assess the effects of adding 25 000 punti and/or mola ha−1 on the large carp and environment, and to assess the effects of punti on mola and mola on punti. It was found that catla was not affected by the addition of small fish in any of the combinations tested; rohu was not affected by punti, and mola reduced rohu performance by 30–40% only when punti was not present; mirror carp was not affected by punti, and mola increased mirror carp growth rate and harvesting weight by 25–30% whether punti was present or not; small fish did not significantly affect total yield and food conversion ratio; punti performance was not affected by mola; mola harvesting weight was not affected by punti, while mola harvesting numbers and biomass were reduced by 55–65% by punti. Factor analysis of water quality data identified photosynthesis–respiration and algal biomass– temperature as the main processes governing water quality. Effects of treatment on those water quality factors are analysed, and the fish–water quality relationships discussed. In a parallel polyculture experiment in 25 farm ponds, the performance of large carp species was found to be unaffected by the addition of punti and/or mola. The results indicate that, at the densities tested, punti and mola addition to the large carp polyculture is viable as they do not reduce cash crop production and might be a good food source for the farmer's family.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2109.2003.00784.x
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  • 4
    Electronic Resource
    Electronic Resource
    Environmental effects of common carp Cyprinus carpio (L.) and mrigal Cirrhinus mrigala (Hamilton) as bottom feeders in major Indian carp polycultures (2002)
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 33 (2002), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: A polyculture experiment with the large carp rohu, catla and either mrigal or common carp (as cash crop fish), and the small indigenous fish punti (as food for the farmer's family) was carried out at Bangladesh Agricultural University, Mymensingh. The main objectives were to compare polycultures of large carp in which the bottom feeder is either the native mrigal or the exotic common carp, and to assess the effects of adding the small indigenous species punti to those polycultures. The results of fish–fish interactions and overall fish production have already been reported. The present paper presents the effects on the water quality, and discusses fish–environment interactions. The main conclusions are: time changes in the pond environment were stronger than fish composition effects. The main practice affecting water quality was liming, that incresed alkalinity, pH and water transparency and decreased ammonia. Rain affected photosynthesis and the match-mismatch of the two steps of nitrification. The more that bottom feeding fish species disrupt the mud bottom, the stronger their effects on pond environment. Common carp produce the strongest disruption of the mud bottom, followed by punti and then by mrigal. Mud disruption produced by common carp leads to a stronger liming effect, nutrient release into the water, and provides more particles that rain-floods wash out, facilitating the mismatch of the two steps of nitrification, and increased phosphorus adsorption into the mud bottom. Mud disruption by punti is only enough to improve the liming effect. Mud disruption by mrigal is the least, hence less particles are resuspended, nitrification is not affected during floods and relatively more phosphate remains in the water available for photosynthesis. The bottom feeder common carp can be seen not only as a target-cultured fish but also as a management tool. Farmers can get double benefit in introducing common carp in the ponds as it enhances the effectiveness of lime application and increases the availability of nutrients to phytoplankton. Through the manipulation of species in the polyculture alone, farmers can maintain the environment better and also reduce input costs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2109.2002.00753.x
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of adding different proportions of the small fish punti (Puntius sophore) and mola (Amblypharyngodon mola) to a polyculture of large carp (2004)
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 35 (2004), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: This experiment was carried out in the framework of a project to develop a viable fish polyculture technology under Bangladeshi conditions that allows simultaneous fish production of small indigenous species for the farmers' family consumption and of large carp species as a cash crop. The objectives of this experiment were to assess the effects of adding punti and mola in different proportions on the large carp and on the environment, and to assess the effects of punti on mola and mola on punti. The polyculture included the large carp rohu, catla and common carp (as cash crop fish), and the small indigenous fish punti and mola (as food for the small-scale farmer family). The total large carp stocking density was 10 000 fish ha−1, at a species ratio of 1:1:1. The total small fish stocking densities were 0 in the control and 30 000 punti and mola ha−1 in the treatments, these at rates 2:1, 1:1 and 1:2. Stocking punti and mola at the density and all ratios tested were viable solutions to obtain simultaneously large carp cash crops and small fish to feed the farmer's family. Statistically marginal differences in large carp production were obtained in stocking small fish in the different proportions. These marginal differences could be explained by food competition between punti and common carp and between mola and rohu, which had different outcomes depending on the proportions of the small fish stocked. Stocking punti and mola at a 1:1 ratio would result in more small fish for the farmer's family, while the individual size of rohu, the most expensive large carp, would be somewhat smaller, but not necessarily small enough to decrease its selling price. Stocking one of the small fish in higher proportion than the other (2:1 or 1:2) would result in less mola for the family consumption, while harvesting of common carp would be somewhat lower and of smaller fish. Since common carp is the cheapest of the large carps, this small reduction would not necessarily affect the family income in an important way. With these results, farmers would now be able to reorganize their stocking practices with large carps and small fish and decide the appropriate small fish stocking ratios to meet their needs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2109.2004.00990.x
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  • 6
    Electronic Resource
    Electronic Resource
    The effect of common carp, Cyprinus carpio (L.) and mrigal, Cirrhinus mrigala (Hamilton) as bottom feeders in major Indian carp polycultures (2002)
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 33 (2002), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: A polyculture experiment with the large carp rohu, Labeo rohita (Hamilton), catla, Catla catla (Hamilton) and either mrigal, Cirrhinus mrigala (Hamilton) or common carp, Cyprinus carpio (L.) (as cash crop fish), and the small indigenous fish punti, Puntius sophore (Hamilton) (as food for the small-scale farmer family) was carried out at the Field Laboratory of the Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh. The main objective was to compare polycultures of large carp in which the bottom feeder is either the native mrigal or the exotic common carp. Secondary objectives were to assess the effects of adding the small indigenous species punti to polycultures of large carp, and to compare the effects of mrigal and common carp on punti production and reproduction. It was found that (i) common carp damaged embankments, had no effect on catla, improved rohu performance by 50% and total fish production by 20%; (ii) punti addition did not affect rohu, catla and total yield, improved mrigal performance by 50%, and decreased common carp performance by 20%; and (iii) punti was not affected either by common carp or by mrigal. However, its performance was not satisfactory, probably owing to frequent netting, which might have hindered growth and breeding. In spite of the embankment damage caused by common carp, this bottom feeder seems to be more promising than mrigal, because it leads to higher fish production. The addition of punti to the large carp polyculture is a viable proposition, as it does not reduce cash crop production, and might be a good food source for a small-scale farmer's family.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2109.2002.00654.x
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  • 7
    Electronic Resource
    Electronic Resource
    Human and porcine early kidney precursors as a new source for transplantation (2003)
    [s.l.] : Nature Publishing Group
    Nature medicine 9 (2003), S. 53-60 
    Details
    ISSN: 1546-170X
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Kidney transplantation has been one of the major medical advances of the past 30 years. However, tissue availability remains a major obstacle. This can potentially be overcome by the use of undifferentiated or partially developed kidney precursor cells derived from early embryos and fetal tissue. ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nm812
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  • 8
    Electronic Resource
    Electronic Resource
    Enhanced stability of laccase in the presence of phenolic compounds (2000)
    Springer
    Applied microbiology and biotechnology 54 (2000), S. 510-514 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The storage stability of laccase (EC 1.10.3.2) from the white-rot basidomycete Trametes versicolor in potassium-citrate buffer was enhanced by various phenolic compounds as well as by lignin sulfonate. The highest storage stability was obtained with phenolics, e.g. phloroglucin and 3,5-dihydroxybenzoic acid; these represent substrates of laccase which are oxidized slowly because of their relatively high redox potential and which did not precipitate from the solution within the tested period of time. Sterilization enhanced the stability of laccase but additional stabilization by phenolics was observed both under sterile and non-sterile conditions. We thus concluded that stabilization occurred not only through prevention of microbial degradation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002530000452
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  • 9
    Electronic Resource
    Electronic Resource
    Tilapia wild spawning control through predator fishes: Israelitrial with red-drum and hybrid bass (2000)
    Springer
    Aquaculture international 8 (2000), S. 31-40 
    Details
    ISSN: 1573-143X
    Keywords: bass (Morone saxatilis × M. chrysops) ; fish culture management ; predator control ; red-drum (Sciaenops ocellatus) ; tilapia (Oreochromis niloticus × O.aureus) ; warm water aquaculture ; wild spawning control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Tilapia wild spawning is a nuisance in warm freshwater aquaculture growout ponds. To cope with this problem two experiments were carried out with predatory fish that do not reproduce in fresh water. One experiment tested the capacity of hybrid bass (Morone saxatilis × M. chrysops) and red-drum (Sciaenops ocellatus) as predators of wild spawning of hybrid tilapia (Oreochromis niloticus × O.aureus), and the other compared predation effectiveness of red-drum of different sizes and stocking densities. Both hybrid bass and red-drum effectively reduced tilapia wild spawning and improved by 15–20% tilapia performance and food conversion ratio. These effects were obtained stocking small red-drum (20 g) or large red-drum (60–80 g) or bass (135 g) at stocking densities of 500–1000 predators/ha, together with 15000 tilapia/ha of 65–75 g. Hybrid bass stocked at 750/ha and large red-drum stocked at 500/ha presented over 90% survival. Red-drum at higher stocking density and/or lower stocking weight presented reduced survival (40–60%). Red-drum of all examined stocking weights presented better growth rates when stocked at 500/ha than at higher densities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009268815430
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  • 10
    Electronic Resource
    Electronic Resource
    Effect of density on survival and growth of cyprinid fish fry (2000)
    Springer
    Aquaculture international 7 (2000), S. 399-411 
    Details
    ISSN: 1573-143X
    Keywords: common carp Cyprinus carpio ; fry density ; goldfish Carassius auratus ; koi Cyprinus carpio ; management ; nursery pond ; ornamental fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract One of the bottlenecks in Israel's cold water ornamental fish industry is the large loss of fish during the post-larval stage. As a first step towards increasing survival rates, the optimal stocking density in earthen ponds for fry of each species should be determined. The results of five consecutive experiments with fry of goldfish (Carassius auratus), common carp and koi (respectively, edible and ornamental morphotypes of Cyprinus carpio) are presented here. The experiments were run in 18 cages of 1 m3 and 0.8 mm mesh size placed in a 0.02 ha earthen pond, stocked at 50,100 and 200 fry per cage. The variables analyzed were growth rate, harvesting weight, biomass and survival. Equations to estimate growth rates under different conditions are given. The three fish types present different growth rates and survival patterns in relation to stocking density and season, which lead to different management implications. Koi can be stocked up to 2 million fry per ha without showing negative density effects. Goldfish should be stocked at low density (500,000–1 million fry per ha) in spring and at higher rate (2 million fry per ha) in summer. Common carp stocking density should be adjusted to obtain the required fish size at harvest.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009282805391
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