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  • 1
    Electronic Resource
    Electronic Resource
    Assessment of Ovarian Development and Its Relation to Mating in Wild and Pond-Reared Litopenaeus vannamei Shrimp in a Commercial Hatchery (2003)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 34 (2003), S. 0 
    Details
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The present study compares three scales for evaluation of ovary development stage in wild and pond-reared shrimp. An external visual scale was assessed according to color and size of ovaries observed through the exoskeleton in live shrimp by staff of a commercial hatchery. Shrimp were then sacrificed to obtain gonadosomatic index, and gonads were scaled according to their color and size upon dissection. Finally, a portion of ovaries was processed for histological analysis, from which oocyte diameters were obtained, and females were evaluated with another scale based on cytological organization of gonads and on frequency of oocyte sizes. The certainties of the external and internal scales were analyzed, based on differences in gonadosomatic index and oocyte diameter and by comparison with the more accurate scaling obtained by histological analysis. The external scale was, in general, less accurate than the internal scale. Maturation stage in pond-reared shrimp was underestimated or overestimated more frequently than in wild shrimp. The implications for hatchery operation and possible reasons are discussed. Pond-reared shrimp were found to have a non-linear relation between gonad weight and body weight, but this relation was linear for the larger wild shrimp. This reduced the validity of gonadosomatic index in pond-reared shrimp, which were still growing. Thus, oocyte diameter, which was not affected by body weight in growing shrimp, represents a more accurate numeric measure of ovary development. Spermatophores were found attached to the thelycum in females only at the cortical stage of maturation, independent of origin. However, a significant proportion of fully mature, pond-reared shrimp did not have an attached spermatophore, possibly indicating lower mating success or poorer spermatophore adherence in these shrimp.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-7345.2003.tb00085.x
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  • 2
    Electronic Resource
    Electronic Resource
    Spawning Frequency Analysis of Wild and Pond-Reared Pacific White Shrimp Penaeus vannamei Broodstock under Large-Scale Hatchery Conditions (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 30 (1999), S. 0 
    Details
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Second generation Penaeus vannamei broodstack, pond-reared and wild populations, were compared for spawning frequency and several variables associated with reproductive performance. For this purpose, 470 pond-reared and 237 wild-caught individually tagged females were stocked with males of the same origin in ten maturation tanks in a commercial hatchery, and several productivity variables were recorded over time. Results of the analysis indicate that wild shrimp had higher mating and spawning frequencies compared to pond-reared broodstock. The number of nauplii per spawn was higher for wild shrimp, but fertilization and hatching rates were higher for pond-reared spawners. A larger proportion of nonmating females were found in pond-reared shrimp; whereas, wild females had a higher potential for multiple matings. The spawn quality (fertilization and hatching rates, percentage of viable spawns, and number of nauplii) in consecutive matings did not decline substantially. The present study indicates that selection of females with multiple spawning capabilities can be an important commercial strategy to improve nauplii production over the short term. Pond-reared broodstock can be an adequate source for applying this strategy because of their year-round availability and an overall acceptable reproductive performance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-7345.1999.tb00865.x
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  • 3
    Electronic Resource
    Electronic Resource
    Hemolymph Metabolic Variables in Response to Experimental Manipulation Stress and Serotonin Injection in Penaeus vannamei (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 29 (1998), S. 0 
    Details
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract— The effects of serotonin (5-HT) and the stress of repeated sampling on Penaeus vannamei hemolymph levels of glucose, lactate, triacylglycerol, cholesterol, and total protein were examined. For this purpose, a baseline hemolymph sample was taken and then shrimp were injected with 5-HT (50 μg/shrimp) or saline after which repeated individual samples were taken at 30, 60, and 120 min. Glucose levels tripled in both saline- and serotonin-treated shrimp when compared to baseline values, without any difference between both groups. In contrast, lactate level rose significantly only in the 5-HT group. The levels of this metabolite were significantly higher than in the salineinjection group for all time points. Triacylglycerol decreased in both groups and no substantial differences were observed in cholesterol and protein levels. The results indicate that repeated sampling stress produces strong hyperglycemia and that 5-HT does not produce an additional increase in glucose levels. However. this monoamine strongly increased lactate levels, a response that can be distinguished from stress and probably attributed to glycolysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-7345.1998.tb00658.x
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  • 4
    Electronic Resource
    Electronic Resource
    Sperm Quality Over Consecutive Spermatophore Regenerations in the Pacific White Shrimp Litopenaeus vannamei (2004)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 35 (2004), S. 0 
    Details
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The reproductive potential of males plays an important role in the productivity of captive penaeids. Males present a large variability in their reproductive potential, and thus the selection of appropriate males for reproduction is highly desirable. The present study compares sperm quality at the beginning of the experiment (baseline values) with variations in sperm quality as a result of consecutive spermatophore regenerations. This was done to evaluate possible predictive criteria for optimal sperm quality based on morphological and biochemical criteria in pond-reared Pacific white shrimp Litopenaeus vannamei males. Sperm quality was similar between left and right spermatophore. Sperm count and proportion of normal sperm increased by 86 and 65% (P 〈 0.05) respectively, from baseline values to third spermatophore regeneration. Proportion of dead sperm progressively decreased with consecutive regenerations, attaining values 33% lower by the third regeneration, compared to baseline values. This indicates that no decrease in sperm quality occurs in L. vannamei during consecutive regenerations and that the existing spermatophores at stocking of males should be expelled to have higher sperm quality in regenerated spermatophores. Furthermore, this procedure allows selecting individuals with high baseline sperm quality based on significant correlations between baseline and regenerated sperm quality observed in the present work. Baseline values of glucose concentration in the hemolymph were positively correlated to baseline values of sperm count (r = 03, P 〈 0.05). In contrast, baseline values of several lipids in the hemolymph were negatively correlated to several traits of sperm quality at first sampling (baseline values) or at first regeneration. These results are discussed in terms of nutritional requirements of males and of possible predictive criteria of sperm quality.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-7345.2004.tb01073.x
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  • 5
    Electronic Resource
    Electronic Resource
    Radiation-damage measurements on PVT-based plastic scintillators
    Amsterdam : Elsevier
    Nuclear Physics B (Proceedings Supplements) 32 (1993), S. 384-391 
    Details
    ISSN: 0920-5632
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0920-5632(93)90050-G
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  • 6
    Electronic Resource
    Electronic Resource
    Larval quality in relation to consecutive spawnings in white shrimp Litopenaeus vannamei Boone (2005)
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 36 (2005), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: In this study, we determined the influence of the time broodstock spend in reproduction, and the effect of consecutive spawnings (spawning order) on larval quality of Litopenaeus vannamei. Spawns were sampled at days 1–4, 18–20 and 38–40 after unilateral eyestalk ablation and ordered according to the number of spawns or spawning order (1–11) of each female. Larvae were reared individually to 2-day-old postlarvae (PL2); spawn and larval quality was determined in terms of fecundity, fertilization, hatching, morphometric traits, ammonium stress resistance applied at zoea, salinity stress resistance applied at postlarval stages, and survival during culture. Fecundity was not affected by consecutive spawns, whereas it increased with time spent in production. Nauplii length and survival to zoea and mysis stages decreased with time spent in production, whereas no consistent influence of consecutive spawning was observed. Survival to PL2, and to the ammonia and salinity stress tests did not decrease with increasing time in production or spawning order. This study separated the specific influence of time spent in production (which negatively affects larval quality) and consecutive spawns (which had no effect or had an inconsistent effect), and reinforced previous suggestions that selection of females with multiple spawn capacity would be desirable for production purposes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2109.2005.01298.x
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of sediment on growth and survival of post-larval Litopenaeus stylirostris (Boone, 1931) (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: The sediments from four areas that are used or will be used for shrimp culture were evaluated for their effect on post-larvae growth of Litopenaeus stylirostris. Texture, organic matter, total, and bio-available fraction of phosphorus, manganese, iron, zinc, copper, and cadmium of the sediments were measured. A positive significant correlation was obtained between total and bio-available concentrations of iron, cadmium, and manganese, but not for copper, phosphorus, or zinc. Significant differences in final weight, survival rates, and shrimp yield were obtained among treatments. The highest survival rates were obtained with sediments that had the highest manganese levels. This survival high rate was significantly correlated with total manganese content of the sediment (r=0.92). The highest final weight were obtained in treatments with sediments containing higher levels of phosphorus, which was reinforced by a significant positive correlation between final weight and total and bio-available phosphorus (r=0.94 and 0.95 respectively), while final weight seems adversely affected by high concentrations of copper (r=−0.83) in the sediment. Texture of the sediment influenced shrimp yield, with lower values for sandy sediments relative to silty sediments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2109.2004.01062.x
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of number of spawns on the resulting spawn quality of 1-year-old pond-reared Penaeus vannamei (Boone) broodstock (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: For production of shrimp larvae in a commercial hatchery, multiple spawning of females is highly desirable, provided spawn quality is not affected. Using biochemical and production approaches, 349 females were individually followed, and 69 spawns were sampled over a 3-month period. The quantity of eggs and nauplii per spawn was greater in females with multiple spawns. Several indicators of spawn quality, such as fertilization and hatching rates, per cent of viable spawns, and morphometric characteristics of eggs and nauplii were not affected by consecutive spawns. Analyses of egg and nauplii biochemical composition indicate that adequate transfer of nutrients to eggs is not compromised with successive rematurations and spawnings. Strategies that focus on the selection of shrimp with multiple spawning capacities could be a promising approach to increasing larvae production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2109.2003.00826.x
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  • 9
    Electronic Resource
    Electronic Resource
    TSEE-OSEE properties of some BeO/graphite detectors for dosimetric purposes (1990)
    Springer
    Journal of radioanalytical and nuclear chemistry 139 (1990), S. 113-120 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Experiments in the field of Thermally Stimulated Exoelectron Emission (TSEE) regarding the BeO/graphite (BUG) detector's responses to β, α and neutron radiations, annealing, and optimization of the heating program related to retrapping processes, were performed. Optical Stimulated Exoelectron Emission (OSEE) measurements were made at various wavelengths and the variations explained in connection with literature data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02060458
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  • 10
    Electronic Resource
    Electronic Resource
    A catalytic activity model based on the structural defects of catalysts I.60Co gamma radiation field effect on 1-butene isomerisation on an alumina catalyst (1985)
    Springer
    Journal of radioanalytical and nuclear chemistry 93 (1985), S. 1-8 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The conversion of 1-butene into cis- and trans-2-butene on alumina TA 600 catalyst with and without60Co γ-radiation field, correlated with literature data, is presented. Irradiation sources, reaction set-up and analysis of the products are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02168353
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