The African catfish (Clarias lazera C. and V., 1840) : a new species for aquaculture

NARCIS (Netherlands)

Hogendoorn, H.

1983-01-01

Fish husbandry can contribute substantially to the production of animal protein for human nutrition, especially in tropical countries. To determine the suitability of C. lazera for aquaculture, the propagation and production ,management as well as the growth physiology of this

The Accumulation and Retention of Zine-65 and Cobalt-60 by The Fresh Water Fish CLARIAS LAZERA

International Nuclear Information System (INIS)

Abdel Malik, W.E.Y.; Ibrahim, A.S.; Badawy, S.A.

2003-01-01

Some parameters affecting the accumulation and retention of 65 Zn and 60 Co radionuclides by the fresh water fish CLARIAS LAZERA from the contaminated filtered Ismail ia Canal water(FICW) have been investigated. It has been observed that the accumulated activity (KBq/g) increased with increasing exposure time with the contaminated FICW. This kind of bony fish has been shown to accumulate 65 Zn > 60 Co. The increase of the studied radionuclide carrier concentration in the canal water increased the fish uptake of both radionuclides. The increase of ph of the FICW decreased the accumulated activity by the fish. On the other hand, the retention of those radionuclides by this fish was investigated. It was possible from this study to give preliminary data for the calculation of the radiation dose that might be delivered to man eating the contaminated fish

An Assessment of the Heavy Metal Content of Cat Fish (Clarias Lazera) obtained from the Lower Niger Basin at Idah, Kogi State using Energy Dispersive X- ray Fluorescence (EDXRF) Technique

International Nuclear Information System (INIS)

Amodu, A.E.; Achumu, L. A.; Egwuogu, C.P.

2013-01-01

Five catfish (Clarias lazera) samples obtained from the Lower Niger River Basin at Idah were subjected to elemental analysis by Energy Dispersive X - ray Fluorescence (EDXR) technique. A voltage of 30KV and current of 1mA was applied to produce a 17.441KeV molybdenum X-ray which was used to irradiate the samples for ten minutes. The analysis was performed using the mini pal 4 version PW 4030 X -ray spectrometer at the Center for Energy Research and Training (CERT), Ahmadu Bello University, Zaria, Kaduna State, Nigeria. The elemental composition and concentration of seven major and trace elements: Ca, Cr, K, Cu, Fe, Mn, and V were detected in the samples. The major elements are Ca,K and Fe while the trace elements are Cr,Cu, V and Mn. The concentration of Calcium which is the highest range fro 0.370% to 3.110% while the concentration of Copper which is the least range from 46.030pm to 99.859pm. The result shows the presence of Cr, Cu, Fe, Mn and V which are heavy metals the concentration of Cr, Cu, Fe and Mn in the sample were below World Health Organization (WHO) and Food and Agricultural Organization(FAO) maximum permissible limit of intake of the various minerals respectively. However the concentration of V found in the sample is above the WHO and FAO maximum limit for Vanadium.

Chemical composition of Clarias Lazera (cuv and val., 1840) as an indicator of fish raising in treated sewage effluents

International Nuclear Information System (INIS)

Awad Elkareem, Manal Mohamed El Hassan

1998-07-01

The present study is one of the pioneer studies dealing with the possibility of growing fish in treated sewage water in Sudan. Khartoum sewage treatment plant - Green Belt area - was the main study site for this work, where fish was some how introduced to the canal which receives water from the last stage of treatment. Fish have reached large sizes and numbers, they are highly consumed by people of the area and widely marketed in the nearby localities. So this study aimed to discuss the potential health associated with the utilization of such fish for food, throwing light, on the advantages and disadvantages of fish culture in treated sewage effluent. The research was directed towards the study of the chemical composition of Clarias lazera (Cuv. and Val., 1840) (Garmout fish) being the only fish species in the area during the course of this study . Fish samples were collected from the Green Belt and the White Nile at the vicinity of Jebel Aulia reservoir which was taken as a control area for (April 1995 - April 1996). Basic biology was studies for each specimen, the concentrations of some of the hazardous and potentially hazardous heavy metals were investigated in the flesh of 30, randomly selected fish samples from both study sites, beside the major chemical body constituents : fats, proteins, moisture and ash in all specimens, to determine the quality of the flesh> Data obtained was analyzed, trying to correlate fish chemical composition to the surrounding environment. Treated sewage-fish showed higher weights and lengths than natural water-fish from the White Nile. Most of the hazardous metals investigated in the muscle tissues of treated sewage-fish were found to be of insignificant variation from that of natural water-fish (Mercury and Lead). They were found to be at lower levels than what is recommended by the International Agencies human consumption. The essential micronutrients for fish like Copper, Ferric (Iron) and Zinc showed significantly higher levels

Biochemical and physiological changes in Egyptian Nile fish subjected to varying levels of gamma irradiation

International Nuclear Information System (INIS)

Roushdy, H.M.; El-Kashef, H.S.; Imam, A.E.

1975-01-01

Radiation is nowadays to be considered as a new parameter in the ecology of water masses. Aquatic organisms, perhaps more than any other group of organisms, are directly exposed to radiation hazard and may be subjected to continuous low-level exposure from bottom material and from internal sources accumulated within their own bodies, originating partly from radionuclides released from nuclear facilities into the aquatic environment. In recent years, a large number of papers have been published on the uptake, concentration and release of radioactive material by aquatic organisms. However, radiation experiments on fish, a major source of food for human consumption, are still very rare and mostly restricted to studies on the effect of irradiation on eggs and larvae. Since the study of the radiation effect on living aquatic organisms, particularly fish, is important in connection with the problems of preserving water resources for the benefit of mankind, the work presented here has been done to ascertain the effect of varying dose-levels of gamma irradiation on two common Egyptian Nile fish species, the catfish Clarias lazera and the Tilapia nilotica. Investigations carried out on Clarias lazera involved blood and muscle analyses as well as growth rate measurements. The results obtained showed impaired haematological levels, changes in weight of muscle proteins and, chiefly, retardation in growth rate. Investigations carried out on Tilapia nilotica revealed changes in the activity of certain digestive enzyme systems, glucose level in blood and concentration of the glycogen store in liver and muscles. In discussing the results obtained the authors have taken the relevant literature into consideration. (author)

Changes in haematological levels in gamma irradiated Nile-catfish clarias lazera

International Nuclear Information System (INIS)

Roushdy, H.M.; Imam, A.; Mansour, M.A.

1981-01-01

The aim of this work is to find a method for calculating the slowing down parameters and the data to be used for several types of reactors. The treatment is based on a multigroup collision probability model. In this work 64 groups are used for the slowing down region till the cut-off energy, and one thermal group is used to get the multiplication factor. A good test of this method, as well as of the nuclear data used, is the comparison of age calculated by this method and experimental results. It is tested for light water and graphite reactors. The second part of this work is concerned with flux calculations in light water and graphite reactors, using the slowing down method mentioned above. Ten cases, with different composition, are used for water cells. The enrichment of fuel varies from 1.04% to 1.3%. The moderator to fuel volume ratio varies from 1 to 4. Also another 9 different graphite natural uranium cells, with different moderator to fuel volume ratio, between 34 and 76, are considered. Heterogeneous cells are treated as homogeneous ones, to test the effect of homogeneization on heterogeneous reactor cells (since calculations for homogeneized cells are easier and take negligible time in computation). (author)

Vlijanie dizajna geterostruktury na porog generacii lazera s mnozhestvennymi kvantovymi jamami InGaN/GaN na kremnii

DEFF Research Database (Denmark)

Andryieuski, Andrei

2008-01-01

This article is devoted to the investigation of the influence of heterostructure design on lasing characteristics of the InGaN/GaN multiple quantum well laser on silicon substrate, performed by computer modelling. It is shown that heterogeneity in a growth process can lead to different far-field ...

Transverse Injection Experiment; Injection Transversale; Poslednie dostizheniya v oblasti inzhektirovaniya plazmy poperek magnitnogo polya; Inyeccion Transversal

Energy Technology Data Exchange (ETDEWEB)

Hammel, J. E.; Baker, D. A. [Los Alamos Scientific Laboratory, Los Alamos, NM (United States)

1966-04-15

) [Russian] Dvizhenie plazmy, inzhektiruemoj poperek magnitnogo polja, rassmatrivalos' rjadom avtorov. V rannih jeksperimentah s inzhektirovaniem bystroj (5 Division-Sign 7 * 10{sup 7} sm/sek) i plotnoj (10{sup 14} cm{sup -3}) plazmy poperek magnitnogo polja nabljudalos' pojavlenie poljarizacionnogo jelektricheskogo polja,i struja plazmy peresekala magnitnoe pole s E x B drejfom. Magnitnoe pole slabo vozmushhalos' plazmoj (| {Delta}B/B | <0.1), v to vremja kak skorost' drejfa poperek magnitnogo polja naprjazhennost'ju do 5 kgs byla priblizitel'no ravna skorosti inzhektirovannoj strui. Struja szhimalas' v napravlenii perpendikuljarnom V i V po mere prodvizhenija v oblast' sil'nogo magnitnogo polja. V to zhe vremja izmerenija plotnosti jelektronov interferometricheskim metodom s pomoshh'ju He-Ne lazera pokazyvajut, chto poperechnoe pole naprjazhennost'ju do 7 kgs ne vyzyvaet zametnogo smeshhenija strui v napravlenii polja. Predstavljaet interes povedenie strui, kogda ona peresekaet oblast', v kotoroj magnitnoe pole menjaet svoe napravlenie otnositel'no linii nulevogo polja. Pri peresechenii struej . separatrissy mezhdu dvumja magnitnymi silovymi linijami jelektricheskoe pole dolzhno menjat' napravlenie, esli drejf prodolzhaetsja. Struja ostaetsja v oblasti separatrissy, togda kak vdol' silovyh linij magnitnogo polja izmerjajutsja bol'shie toki, svjazyvajushhie perednjuju chast' strui s posledujushhimi chastjami. Izoljatory, postavlennye dlja preryvanija jetogo toka, pozvoljajut strue dvigat'sja v oblast' polja obratnoj poljarnosti. Ispol'zuja induktivnost', svjazannuju s tokom depoljarizacii strui, mozhno proizvesti razdelenie bystryh i medlennyh komponentov strui. Otsechka medlennogo komponenta strui nabljudaetsja s pomoshh'ju interfe- rometricheskih metodov s primeneniem He-Ne lazera. Izmerenija jelektricheskogo polja v neskol'kih tochkah vdol' techenija pokazyvajut nekotorye iz naibolee slozhnyh osobennostej potoka plazmy. (author)