Study on genetic structure of Caspian Sea sturgeons in the stock assessment of sturgeon in Iranian coastline of the south Caspian Sea

The population genetic structure of the Persian sturgeon (Acipenser persicus) in the 2, 3, 4 fisheries regions and Sefidrud River was investigated based on the DNA sequencing method during 2010–2013 sturgeon stock assessment in the south Caspian Sea . DNA samples were extracted using ammonium acetate, the quantity of DNA was measured at 260 and 280 nm using spectrophotometry by Nanodrop (ND 1000 model), and the quality was checked by 1% agarose gel electrophoresis. Two sets of mitochondrial gene (D-loop and cytochrom b) after synthesis were used for polymerase chain reaction (PCR). A Neighbor-Joining (NJ) tree was constructed for all haplotypes according to Kimura 2-parameter model using Mega Version 4.0.1, number of haplotypes, haplotype diversity (Hd) and nucleotide diversity and their corresponding variances, genetic divergence overall and between paired populations (Fst) by 10,000 permutations and exact test, the gamma distribution shape parameter for the rate heterogeneity among sites and nucleotide sequence, the historical demographic pattern of A.persicus using neutrality tests and mismatch distribution analysis (D test of Tajima and Fs test of Fu), also the concordance of the observed with the expected distribution under the sudden population model using the Harpending, s raggedness index (Hri) were analysed. All calculations were conducted using ARLEQUIN version 3.11 and DnaSP 4.0. The aligned mtDNA sequences of D-loop and cytochrom b genes were consisted of 500 and 700 base pairs (bp) respectively. 13 and 4 haplotypes were defined, the average haplotype diversity were 0.961 and 0.419, average nucleotide diversity were 0.038 and 0.002, The gamma distribution shape parameter were 0.19 and 0.20 indicating moderate mutation rate heterogeneity among sites in A.persicus. The lowest value of Fst for D-loop gene was calculated between Sefidrud and four fisheries region (-0.002) and the Fst values observed for cytochrom b gene was 0.04 with Nm=5.37 and not statistically significant. The exact test of population differentiation (non-differentiation exact P values) showed significant differences between Sefidrud and other areas (P ≤0.05) for D-loop gene and for cytochrom b gene was nonsignificant (P ≥0.05). The mismatch analysis produced a unimodal distribution of pairwise differences for both genes which was consistent with the sudden population expansion model. Tajima’s D and Fu’s Fs statistics were significantly negative (D= -0.84 and - 0.99, P>0.01; Fs=-0.220 and -0.079, >0.01). ARLEQUIN calculated the value of t as 13.65 and the time since population expansion was estimated to be approximately 1501 years before present based on the mutation rates for the control region and this value for cytochrom b gene t= 0.98 which population expansion time was 7.84 years before present. The results of this study based on D-loop gene showed that population of A.persicus in the Sefidrud River is differ from other studied areas. Therefore fisheries managements of this unique and valuable stock for restocking and conservation of gene pools is strongly recommended

Modelling of Short-Term Interactions Between Concrete Support and the Excavated Damage Zone Around Galleries Drilled in Callovo–Oxfordian Claystone

peer reviewedProduction of energy from nuclear power plants generates high-level radioactive nuclear waste, harmful during dozens of thousand years. Deep geological disposal of nuclear waste represents the most reliable solutions for its safe isolation. Confinement of radioactive wastes relies on the multi-barrier concept in which isolation is provided by a series of engineered (canister, backfill) and natural (host rock) barriers. Few underground research laboratories have been built all over the world to test and validate storage solutions. The underground drilling process of disposal drifts may generate cracks, fractures/strain localisation in shear bands within the rock surrounding the gallery especially in argillaceous rocks. These degradations affect the hydro-mechanical properties of the material, such as permeability, e.g. creating a preferential flow path for radionuclide migration. Hydraulic conductivity increase within this zone must remain limited to preserve the natural barrier. In addition galleries are currently reinforced by different types of concrete supports such as shotcrete and/or prefab elements. Their purpose is twofold: avoiding partial collapse of the tunnel during drilling operations and limiting convergence of the surrounding rock. Properties of both concrete and rock mass are time dependent, due to shotcrete hydration and hydromechanical couplings within the host rock. By the use of a hydro-mechanical coupled Finite Element Code with a Second Gradient regularization, this paper aims at investigating and predicting support and rock interactions (convergence, stress field). The effect of shotcrete hydration evolution, spraying time and use of compressible wedges is studied in order to determine their relative influence

Stock assessment of sturgeon fishes in the southern part of Caspian Sea (Iranian water)

The marine survey for sturgeon stock assessment was conducted in summer, winter and spring in the years 2006 and 2009 to estimate the relative and absolute abundance and percentage composition of each species in the Guilan, Mazandaran and Golestan Provinces. This survey was carried out in the Iranian waters of the Caspian Sea on board the Sisara2 and Guilan vessels using trawl nets at 2-100 m depths. Trawling was carried out in 85 stations that were selected using a stratified random design. The number of stations in each scope was based on the area of the scope in terms of the total area. Trawling and sampling in shallow water up to 10 m were carried out using 9 m trawl nets whereas 24.7 m trawl nets were used for depths more than 10 m. Trawl surveys were carried out in the daytime. Trawling velocity was kept at 2.5-3 kts and trawls lasted half an hour in order to calculate abundance, and biomass of sturgeons using the swept area method. Catch per unit area (CPUA) in the winter 2006 survey was 3853 specimens nm^2 , in the summer and winter 2007 survey was 1854 , 2912 specimens nm^2 at depths less than 10 m respectively . CPUA for sturgeons in spring 2008 survey was 2103 specimens nm2 at depths less than 10 m and 393 specimens nm2 at depths greater than 10 m (10-100 m depth). These values in the winter 2008 survey dropped to 44 specimens nm^2 at depths at depths above 10 m. CPUA for sturgeons in the spring 2009 survey was 300 specimens nm^2 at depths less than 10 m and 307 specimens nm^2 at depths greater than 10 m. In all the surveys conducted CPUA for A. persicus was higher than that for the other sturgeon species. Based on the calculations carried out in the marine survey in winter 2006 the estimated absolute abundance for sturgeons was about 2977.363 thousand. The total biomass of sturgeon was estimated as 131.713 tons. In the summer 2007 survey total abundance was estimated 1432.398 thousand, and total biomass of sturgeons was estimated at about 312.161 tons. In the winter 2007 survey total abundance for sturgeons was estimated at about 2250.105 thousand, and total biomass was estimated 578.08 tons. In the spring 2008 survey total abundance was estimated at about 3002.832 thousand. The total biomass was estimated at about 2533.318 tons .In the winter 2008 survey total abundance was estimated at about 152.722 thousand, and total biomass in winter 2008 was estimated 170.540 tons. Total abundance in spring 2009 survey was 1310.232 thousand and total biomass was estimated at 2019.tons. Investigation of stomach content of sturgeon Acipenser persicus caught under 10m depth in 2006 to 2007 surveys showed that there is significant difference in the consumed food. Polychaeta is the major food consumed and crustacean an the minor one(P>0.05).Also no new types of food( such as bony fishes or benthic) have been observed in food chain of Acipenser persicus only the food consumption rate has been related to the season of year and increases or decreases in warm or cold seasons, respectively For physiological study and determination of sexual maturation stages in sturgeon,119 gonad sampling prepared. The results showed that 63 % of fishes were females and 37 % of them were males. Gill microscopic study shows complications such as hyperplasia, curvature, adhesion, embowed, shorting and lengthen of secondary filaments and fraught bloody. Microscopic study on liver indicates signs of cloudy inflammation, fatty degeneration, dispersion of billed secretions and cell atrophy. The population genetic structure of Persian sturgeon (Acipenser persicus) in Sefidrood and Gorganrood rivers watershed analyzed based on microsatellite markers during sturgeons assessment in 2006-2008. Results showed that Acipenser persicus in two region of south part of Caspian Sea are two independent populations

Modifying HMA stone aggregates prone to stripping with lime-based additives

"Stripping" has been known as one of the foremost problems associated with Hot Mix Asphalt pavements since the beginning of asphalt pavement practices. This paper mainly relies on the concept of surface charges in the aggregate-asphalt-water interface. According to this rationale, extent of aggregates surface charges determines their degree of propensity to stripping. This research presents an experimental approach to understand the interaction of lime additives and mineral aggregates in different treatment settings. Three sources of aggregates with different mineral compositions and propensity to stripping were tested. X-Ray Fluorescence and Petrographical analysis were used to identify rock surface elements. Qualitative stripping tests were applied to evaluate the percent coating retained after stripping in different treatment scenarios. Zeta potential of powdered aggregates before and after different treatment settings were measured accordingly. This study identifies any significant correlation among percentage of siliceous minerals in aggregates, their zeta potential characteristics and stripping propensity