The embryonic development of the Mosquito fish(Gambusia affinis) eye lens was investigated using light microscopy .The results indicated that the embryonic development of the lens does not correspond to that of the non spherical lenses of terrestrial vertebrates .This study showed that a very small cavity in the lens vesicle appears during development ,but it differs from that of the mammalian lens. The most important aspect in this study is that ,the posterior edge of the simple cuboidal epithelium which covers the anterior half of the surface of the lens is situated well beyond the equatorial region of the lens .As a result , the germinal and transitional zones became closer to the posterior pole rather than the anterior pole of the lens. This might be an important factor in causing the lens to be spherical rather than being biconvex.
The ceiling of the midbrain has a couple of optic lobes which are prominent and used as an optic center that reflex what it receives from eye retina fibers. The histology of optic tectum has been studied in Iraqi fish Barbus luteus (Heckel) . It was found that the number of optic tectum were six main strata organized from the outside to the inside as follows : the stratum marginal (SM), the stratum opticum (SO), the stratum fibrosum et griseum superficialis (SFGS), the stratum griseum central (SGC), the stratum album central (SAC), the stratum periventricular (SPV), . the tow last strata consider deep layers on the optic tectum. It was noticed that the superficial strata was the first (SM), while the thickest strata was the four (SGC), whic
... Show MoreThe fish assemblage in the East Hammar marsh was studied during December 2009 to May 2010. The fish fauna of the marsh consisted of 17 native, 23 marine (49%) and seven alien species. The dominant species were Liza abu (14.6%), Carassius auratus (13.4%) and Thryssa mystax (11.2%). The resident species formed 44.7%, occasional species 36.1% and seasonal species 19.2% of the total number of fish species. Fish species diversity index ranged from 1.28 to 2.61, richness from 1.98 to 4.50 and evenness from 0.45 to 0.78. Salinity ranged from 1.45 to 7.74‰. The increase in the proportion of marine species (49%) in the fish assemblage due to marine waters progress from Arabian Gulf had an impact on the values of ecological indices and the
... Show MoreThe neighbourhood unit is a small local community in a city dwelled by certain number of dwellers who are characterized by common features, mostly economic. They daily deal with each other & unified with the feeling of neighbourhood. The daily primary services are available in this small community (like education, shopping & entertainment). This community is separated from other communities by physical boundaries like streets, gardens… etc. The neighbourhood is not an exotic notion on human community but it is as ancient as history itself since it was there in ancient communities that dwelled on earth. Complications of urban life needs, caused by cities’ expansion, and the weakness of social relationships, imposed phy
... Show MoreTheoretical study computerized has been carried out in electron optics field, to design electrostatic immersion lens , the inverse problem is important method in the design of electrostatic lenses by suggesting an axial electrostatic potential distribution using polynomial function. The paraxial –ray equation is solved to obtain the trajectory particles that satisfy the suggested potential function. In this research, designed immersed lens length L = 10mm operated under zero condition, as it was obtained the electrode shape of this lens solutions using the Laplace equation The results of the search showed low values of spherical and chromatic aberrations, which gives a good indication of the design of the lens. It was
... Show MoreThe micronucleated erythrocytes in fish was used to detect water pollution by genotoxic agents. Fish belonging to different species were collected from three regions from Baghdad during three months (December/2000,January and February/2001 ).The micronucleated erythrocytes was observed in all the specimens. It was concluded that the genotoxic activity' in one region was less than in die other two regions.?
The present study was done to identify the karyotype of Mystus pelusius fish , which is the only representative of the family Bagridae in Iraq, they have been caught from Tigris river in AL-Kraat area of Baghdad city, the results show that the diploid chromosome number was 2n=32 and the males chromosomal types included 2n=(6m+13sm+7st+6t)and fundamental number FN=51, in females chromosomal types included 2n=(6m+12sm+8st+6t)with FN=50,also it observed that the first submetacentric pair was the largest within the biarmed chromosomes .The results revealed that the male heterogamety and the female homogamety , accordingly it follows the sex determination system (XX / XY) , as the (X) chromosome represented by medium sized submetacentr
... Show MoreThe concentrations of Pb, Zn, Hg and Cu were determined in twenty sample of canned fish, samples were collected with different origin with two meals from local markets at Baghdad city for the period (October 2012-February 2013),results of study were appeared variation in mercury concentration of canned fish between November and February .The highest concentration of mercury (0.1 mg/kg) was observed in “Hawesta” brand and “Ocean wave” ” brand , the lowest average concentration for mercury 0.01ppm in “Habar”,”Durra” and ”Sayad” brand during( Nov.2012-Feb.2013 ) and have not recorded any concentration for mercury in “Yasmine” brand during (Nov. 2012-Feb. 2013).The maximum level of zinc reached in November. rather t
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