37 resultados para Z-source
em Aquatic Commons
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Leonard Carpenter Panama Canal Collection. Photographs: Views of Panama and the Canal. [Box 1] from the Special Collections & Area Studies Department, George A. Smathers Libraries, University of Florida.
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The paper traces the history of the different documentation media used for information dissemination. Such early media are clay tablets, papyrus, and vellum or parchment codex. The invention of printing however revolutionized the information industry, enabling the production of books in multiple copies. Photography came into documentation mainly to preserve rare materials and those that easily deteriorate. This paper reports the efforts of National Institute for Freshwater Fisheries Research (NIFFR) and Kainji Lake Fisheries Promotion Project (KLFPPP), Nigeria, to develop an Object Oriented Database (OOD) using photographs. The photographs are stored in digitized form on commercial computers, using the program ACDSee 32 for classification, description and retrieval. Specifically the paper focuses on photographs in fisheries as visual communication and expression. Presently, the database contains photo documents about the following aspects of Kainji Lake fisheries: fishing gears and crafts, fish preservation methods
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This study, though, has as its core objective cost reduction in aquaculture nutrition was equally designed to investigate the value of the peels of cassava (Manihot utillisima) as energy source in the diet of Oreochromis niloticus fry. Three levels of cassava peels diet and a control (100% yellow maize in the carbohydrate mixture) was prepared and tested on O. niloticus fry for ten (10) weeks. The fry with mean weight of 0.32g were grouped fifteen (15) in each of the glass aquaria measuring 60x30x30cm with a maximum capacity of 52 litres of water. The fry were fed twice daily at 10% biomass. Weekly, the fry were weighed to determine the weight increment or otherwise and the quality of feed adjusted accordingly. Water quality parameters like temperature, pH and dissolved oxygen (D.0) were monitored and found to be at desirable level. DT 3 (97 % cassava peels and 3% yellow maize) in the carbohydrate mixture gave the best growth performance. The fry fed, this diet gained mean weight of 1.18g for the period of the experiment. However, the poorest performance in terms of growth was from fry fed the control diet (100%yellow maize in the carbohydrate mixture) fry fed this diet gained mean weight of 0.80 for the duration of the experiment. Analysis of the various growth indices like SGR, PER, FCR and NPU shows that DT3 was the overall best diet with an SGR value of2.40 and FCR of 43.83. However, DT 1 (70% cassava peels and 30% yellow maize) gave the poorest SGR of 1.61 and FCR of 67.58. The difference in weight gain among the fry fed the three levels of cassava peels diet and the control was not statically significant (P>0.05)
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The study was designed to investigate the value of the peels of yam (Dioscorea rotundata) as energy source in the diet of Oreochromis niloticus fry and to investigate the level of inclusion of this peels that will give optimum growth performance. Four diets, three levels of yam peels and a control, was prepared and tested on O. niloticus fry (mean weight of 0.27g) for ten weeks. Fifteen (15) O. niloticus fry were grouped in each of the glass aquaria, measuring 60x30x3Ocm and with a maximum capacity of 52 liters of water. The fry were fed twice daily at 10% biomass. The fry were weighed weekly to determine weight increment or otherwise and the quality of feed was adjusted accordingly. DTl (70% yam peels and 30% yellow maize) in the carbohydrate mixture gave the best performance. The fry fed this diet, gained a mean weight of 1.20g for the period of the experiment. The poorest performance in terms of growth was from fry fed the control diet (100% yellow maize in the carbohydrate mixture). Fry fed this diet gained mean weight of 0.80g for the duration of the experiment. Analysis of the various growth indices like SGR, PER, FCR and NPU shows that DTl was the overall best diet with an SGR value of I. 92 and FCR of 54.10. The difference in weight gain by fry fed the three levels of yam peels diet and the control diet (100% yellow maize) was not statistically significant (P>0.05)
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In recent years interest in the production and description of kinin-type substances has been greatly intensified. So, for example, bradykinin, phyllokinin, physalaemin, ranatensin and caerulein could be extracted from the skin of amphibians as well as. eledoisin out of the salivary glands of Eledon moschata. An examination of lampreys seemed to us particularly profitable in the search for the incidence of further kinins. Ammocoetes of different sizes and also adults of both sexes of the species Eudontomyzon danfordi vladykovi were studied in this research. This species is found in many tributaries of the Danube. Skin extracts were tested on on isolated rat uterus, rat duodenum, guinea pig ileum and rabbit jejunum, further tests were done in order to determine a peptide character of the biologically active substance.
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The reaction of Mn(II) with water-dissolved oxygen, to a higher manganese hydroxide in an alkaline medium, as with the longstanding classic Winkler method, is the first step in the method described here. The assumption for faultless results by the conventional and modified Winkler method is clean water, which contains no organic substances by Mn(III) or Mn(IV). In many cases, however, eg. in river and lake-water tests, it can be seen with the naked eye that after some time the originally brown-coloured precipitate of manganese hydroxide becomes more and more colourless. Oxygen content was analysed in the water samples and evaluated by raising the amount of the leuko-base and giving the corresponding dilution of the colouring matter solution formed still higher oxygen contents can be measured.
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In a lake the nitrogen compounds are liable to regular cycling in which nitrate is reduced and ammonium oxidised. As a nitrate maximum is regularly established in the upper part of the hypolimnion of a stratified summer lake, the authors have dealt in particular with the oxidising side of the nitrogen cycle. Described here are partial results of the nitrification in Plusssee. The Plusssee was chosen, since it is almost entirely without inflows, and, lying in a wooded basin, is well protected from the wind, and therefore stably stratified. In order to determine the number of autotrophic nitrificants the distribution of the Nitrosomonas and Nitrobacter spores in the lake were analysed. From the estimates on the determination of spore numbers of the heterotrophic nitrificants, 14 species in the pure culture were isolated and examined from morphological, biochemical and taxonomic viewpoints.
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Pseudomonas aeruginosa has for some time been known as a denitrifier. Pseudomonas aeruginosa was chosen for further studies, because P. aeruginosa occurs abundantly in Plusssee and moreover there are contradictory assertions on the gas products of denitrification by this bacteria. In experimental research the pattern of growth and gas production of Pseudomonas aeruginosa on nutrient broth was studied.
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The most important aim of this study lay in filling in the great gap in our knowledge of the processes of germination in the Ceratium cyst and the early developmental stages in the standing stock of Ceratium hirundinella. contained rich cysts, we now succeeded extraordinarily well in pursuing the consistent development of Ceratium from the cyst to the completed cell. A series of experiments were carried out on the cysts and the juvenile stages of Ceratium, which showed very interesting results. The author presents in a general descriptive part the normal processes of germination in Ceratium cysts and the development of the juvenile stages in order to show in an experimental part the changes in form of C. hirundinella under the influence of temperature, light and varying salinities.
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This review deals with the variation in populations of invertebrates and the relationships between invertebrate production and detrital food material in chalk streams. The total quantity of detrital material processed by invertebrate consumers is many times greater than the production of these consumers. The amount of detritus ingested each year by chalk stream invertebrates may well be similar to the annual input of autochthonous primary production plus that from allochthonous tree cover.
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Procedures for sampling genomic DNA from live billfishes involve manual restraint and tissue excision that can be difficult to carry out and may produce stresses that affect fish survival. We examined the collection of surface mucous as a less invasive alternative method for sourcing genomic DNA by comparing it to autologous muscle tissue samples from Atlantic blue marlin (Makaira nigricans), white marlin (Tetrapturus albidus), sailfish (Istiophorus platypterus), and swordfish (Xiphias gladius). Purified DNA from mucous was comparable to muscle and was suitable for conventional polymerase chain reaction, random amplified polymorphic DNA analysis, and mitochondrial and nuclear locus sequencing. The nondestructive and less invasive characteristics of surface mucous collection may promote increased survival of released specimens and may be advantageous for other marine fish genetic studies, particularly those involving large live specimens destined for release.
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The magnitude of apparent specific dynamic action (SDA), the maximum rate of oxygen consumption and the length of time that the rate of oxygen uptake remained elevated above the prefeeding level were measured in the Pearl Spot, Etroplus suratensis, fed isonitrous test diets (D 1 - D 4 ) with varying nutrient sources. Irrespective of the diets, the metabolic rate increased immediately after feeding and reached the maximum within 3 to 4 hours. The source of nutrients in the diet significantly altered the magnitude of SDA. It was maximum (91.76% and 129.56%) for those fed on diets D 2 and D 3 and minimum 46.47% and 50.30% for those fed on diets D 1 and D 4 , respectively.
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The increasing harvest of 7 edible seaweeds in Fiji and their importance to the economy of indigenous Fijians are discussed. Traditional methods in the collection, preparation and consumption of seaweeds by the Fijians are also presented.
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Zostera marina is a member of a widely distributed genus of seagrasses, all commonly called eelgrass. The reported distribution of eelgrass along the east coast of the United States is from Maine to North Carolina. Eelgrass inhabits a variety of coastal habitats, due in part to its ability to tolerate a wide range of environmental parameters. Eelgrass meadows provide habitat, nurseries, and feeding grounds for a number of commercially and ecologically important species, including the bay scallop, Argopecten irradians. In the early 1930’s, a marine event, termed the “wasting disease,” was responsible for catastrophic declines in eelgrass beds of the coastal waters of North America and Europe, with the virtual elimination of Z. marina meadows in the Atlantic basin. Following eelgrass declines, disastrous losses were documented for bay scallop populations, evidence of the importance of eelgrass in supporting healthy scallop stocks. Today, increased turbidity arising from point and non-point source nutrient loading and sediment runoff are the primary threats to eelgrass along the Atlantic coast and, along with recruitment limitation, are likely reasons for the lack of recovery by eelgrass to pre-1930’s levels. Eelgrass is at a historical low for most of the western Atlantic with uncertain prospects for systematic improvement. However, of all the North American seagrasses, eelgrass has a growth rate and strategy that makes it especially conducive to restoration and several states maintain ongoing mapping, monitoring, and restoration programs to enhance and improve this critical resource. The lack of eelgrass recovery in some areas, coupled with increasing anthropogenic impacts to seagrasses over the last century and heavy fishing pressure on scallops which naturally have erratic annual quantities, all point to a fishery with profound challenges for survival.
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This is the Report of 1996 survey of Trout Beck with particular reference to spawning gravel quality and invertebrates as a food source for salmonids produced by the Environment Agency North West. Whilst the main River Derwent is quite a high profile salmon fishery, Trout Beck is not a significant fishery in its own right, but serves to maintain the genetic integrity of the wild populations of trout and salmon in the catchment by providing a unique habitat. This survey addressed the invertebrate food availability, and additionally looked at the substrate to try to determine whether the bed type might actually be unsuitable for spawning, especially in view of the previously mentioned silt inputs.