JWSS - Journal of Water and Soil Science

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In modern programmes of animal breeding, the polymorphisms of the milk proteins can be used as marker systems. Beta-Lactoglobulin is the major milk whey protein in the ruminants. The BLG coding gene located on ovine chromosome 3. This protein, synthesis in the mammary glands during pregnancy and the lactation stages. Studies have indicated that this protein is polymorphic in the many breeds of sheep. This is the result of a single base pair substitution in the Beta-Lactoglobulin gene that also rises to the RsaI restriction fragment length polymorphism (RFLP). The aim of this work was to analyze the genotype distribution of Beta-Lactoglobulin in sheep. Blood samples were supplied from 142 sheep of the 5 breeds (Ghezel, Afshari, Moghani, Makoii and Arkharmerino). Genomic DNA was extracted from the 200ul blood sample according to Boom et al. (1989) method modified by Shaikhayev (1995). The Gel monitoring and the spectrophotometeric methods were used for determination of the DNA quality and quantity. the Primers BLG5 and BLG3 amplified a 452 bp fragment from the exon II of the ovine Beta-Lactoglobulin gene. the Products of the amplification were recognized by the electrophoresis on the 1% agarose gel stained with ethidium bromide. The RsaI enzyme was used for restriction of the PCR products. The digested products were separated by the electrophoresis on the 8% nondenaturant polyacrylamide gel and visualized after staining with the ethidium bromide on UV transillumination. The popGen32 software (ver.1.31) was used to estimate the allele and the genotype frequencies, the Hardy-Weinberg equilibrium and dendrogram of the genetic distance. The frequency of A-allele in Ghezel, Afshari, Moghani, Makoii and Arkharmerino breeds was 56%, 34%, 36%, 53% and 48% respectively. The populations were in Hardy-Weinberg equilibrium except to Afshari breed. The lowest genetic distance was observed between Moghani and Afshari breeds and the highest genetic distance between Ghezel and Afshari breeds. The results of this study indicated that PCR-RFLP is an appropriate tool for evaluating genetic variability in sheep.

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  A labyrinth spillway is an overflow spillway to regulate and control flow in canals, rivers and reservoirs. The main hypothesis for the development of such a spillway is to increase the discharge per unit width of structure for a given headwater. This type of structure is often an efficient alternative to a gated-spillway type where either the increase of the flood-passage capacity or the control of the water surface upstream is concerned. This study was aimed to investigate the hydraulic performance of labyrinth spillways of general trapezoidal planform with simple curved apexes. In the experimental work, twelve spillway models with double cycles were considered using three different curved apexes (R/w= 0.15, 0.2, 0.25), each with four different crest heights (w/P= 1.5, 2, 3, 4). Based on the cited recommendations, the length magnification was set to a constant ratio of (l/w= 3) the crest shape was to be of a semi-circular form with simple radius (r= 15 mm) and the spillway walls were vertical with the thickness of T= 2r. An intensive experiment was carried out over a wide range of flows, providing 720 flow data ranging from free flow to submerged flow conditions. 1D flow equation was presented using combined mathematical and dimensional analysis. A coefficient of discharge, C_d, was introduced to represent the influence of the effective geometric and hydraulic parameters on the flow capacity over the spillway. Modular limit was also controlled to see whether the flow over the spillway would be submerged. The results of the study indicate that the modified curved planform of the spillway apexes with consistent divergence in the downstream channel introduces a significant improvement in the flow efficiency over the labyrinth spillways. Spillways with narrower curved apexes (i.e. R/w≤ 0.2), and with the vertical-aspect ratio of (2≤w/P<3) provide more stable and higher hydraulic performance than any other labyrinth planforms over a wide range of flows (i.e. 0.10/P<0.6). In terms of the flow capacity, the proposed spillway model is shown to be more efficient than other zig-zag planforms (i.e. triangular and trapezoidal shapes) with an identical crest length.

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