34 research outputs found

    Abundance, spawning season and type of gattan (Barbus xanthopterus Heckel, 1843) in south of Karkheh River and Hour-Al-Azim marsh (Khuzestan Province)

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    In this study 401 specimens of Gattan (Barbus xanthopterus) caught by drifting and set gillnets, cast nets and forks were studied. Samples were collected monthly (October 1996 to September 1997) from Hamidieh Dam to Hour-Al-Azim Lagoon. Morphometric and meristic parameters and biological characteristics were studied in the laboratory. The Highest frequency of Gattan in the river was in March and in Hour-Al-Azim was in December. The length range of the fish in the river was broader than in the hour, and fishes with lengths more than 700mm were only observed in the river. Sharp decrease in GSI in May and occurence of spawning in May and June showed that reproduction of this species occurs in spring (in a two month period) and is relatively short. Minimum and maximum ova diameter were 0.01mm and 2.25mmin stages II and IV of gonad maturity respectively. An increasing trend in ova diameter up to April and decreasing in June showed one time spawning of this species. Surface water temperature in the spawning season was between 25.5oC and 28.65oC and turbidity was in its lowest level in this period. Sex maturation in males occurred in length of 151-200mm (one year old), and in females in 501-550mm (3 years old). Average sex ratio (male to female) was 1:1.31 which is not significantly different from 1:1 (95% confidence limit)

    Associations of vitamin D binding protein variants with the vitamin D-induced increase in serum 25-hydroxyvitamin D

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    Background: Vitamin D deficiency is a global problem that may be improved by vitamin D supplementation; however, the individual's response to the intervention varies. We aimed to investigate possible genetic factors that may modify the impact of environmental exposure on vitamin D status. The candidate gene variant we investigated was the Gc gene-rs4588 polymorphism at the vitamin D receptor (DBP) locus. Methods: A total of 619 healthy adolescent Iranian girls received 50000 IU of vitamin D3 weekly for 9 weeks. Serum 25(OH) D concentrations, metabolic profiles and dietary intake were measured at baseline and after 9 weeks of supplementation. The genotypes of the DBP variant (rs4588) were analyzed using the TaqMan genotyping assay. Results: Our results revealed that the rs4588 polymorphism might be associated with serum 25-hydroxy vitamin D both at baseline (p value=0.03) and after intervention (p value=0.008). It seemed that the outcome of the intervention was gene-related so that the subjects with common AA genotype were a better responder to vitamin D supplementation (Changes (%) 469.5(427.1) in AA carriers vs. 335.8(530) in GG holders), and carriers of the less common GG genotype experienced a rise in blood glucose after 9 weeks (Changes (%) 0 (1.5)). Our findings also showed that the statistical interaction between this variant and supplementation was statistically significant (intervention effect p-value<0.001 and p-value SNP effect=0.03). The regression model also revealed that after adjusted for potential confounders, likelihood of affecting serum 25(OH)D in individuals who were homozygous for the uncommon allele G was less than those homozygous for the more common AA genotype (OR=4.407 (1.82-8.89); p=0.001). Conclusion: Serum vitamin 25(OH) D following vitamin 25(OH) D3 supplementation appears to be modified by genetic background. The Gc genetic variant, rs4588 encoding the vitamin D receptor seems to influence the response to vitamin D supplementation. Key words: Total 25(OH) D, Supplementation, Gc gene, rs4588

    Elimination of Mn3Ga with Low Crystal Symmetry in Alloying Mn-Ga by Ge Addition

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    In this paper, milling was investigated as a method for production of Mn-Ga binary alloys and the effect of milling process on phase formation of Mn:Ga samples with 2:1 and 3:1 ratio within 1, 2 and 5 hour milling times was studied. For Mn:Ga samples, according to the results, Mn1.86Ga compound with tetragonal structure and I4/mmm space group was a stable phase. Also, some amounts of&nbsp; Mn3Ga compound with orthorhombic structure and Cmca space group was observed in the Mn:Ga solution. The effect of Ge addition, with the purpose of&nbsp; replacing Ge with Ga was also studied in Mn:Ga:Ge (3:0.5:0.5) sample. Although improved magnetic properties is expected with the addition of Ge, but increasing the coercivity was occurred, and saturation magnetization did not change significantly in the studied sample. Ge addition caused elimination of the possibility of formation of asymmetric orthorhombic Mn3Ga phase. In return, two new structures of Mn11Ge8 and MnGaGe were appeared. This phase change was confirmed by studying magnetic behaviour of samples. This behavior can be caused by unbalanced electrostatic forces resulting from Mn-Mn exchange interaction in Mn3Ga orthorhombic structure and substitution of some Ge atoms with Ga

    Historical tsunami in the Makran Subduction Zone off the southern coasts of Iran and Pakistan and results of numerical modeling

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    Tsunami hazard in the Makran Subduction Zone (MSZ), off the southern coasts of Iran and Pakistan, was studied by numerical modeling of historical tsunami in this region. Although the MSZ triggered the second deadliest tsunami in the Indian Ocean, among those known, the tsunami hazard in this region has yet to be analyzed in detail. This paper reports the results of a risk analysis using five scenario events based on the historic records, and identifies a seismic gap area in western Makran off the southern coast of Iran. This is a possible site for a future large earthquake and tsunami. In addition, we performed numerical modeling to explain some ambiguities in the historical reports. Based on the modeling results, we conclude that either the extreme run-up of 12-15 m assigned for the 1945 Makran tsunami in the historical record was produced by a submarine landslide triggered by the parent earthquake, or that these reports are exaggerated. The other possibility could be the generation of the huge run-up heights by large displacements on splay faults. The results of run-up modeling reveal that a large earthquake and tsunami in the MSZ is capable of producing considerable run-up heights in the far field. Therefore, it is possible that the MSZ was the source of the tsunami encountered by a Portuguese fleet in Dabhul in 1524
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