110 research outputs found

    Limnological survey on the most important rivers in the Iranian southern soasts of the Caspian Sea in the Guilan Province with emphasize on the pollutants (Hevigh, Karkanrud and Shafarud rivers)

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    In order to create a reliable ecological database for Guilans running waters(north Iran near the Caspian sea), at the first step 3 important rivers containing Hevigh, Karkanrud and Shafarud, were selected and limnological survey, during autumn 1380 and summer1381 were seasonally carried out for them. Results showed that the key physico-chemical parameters such as dissolved O2, BOD5, pH, Phosphate, Nitrate, Nitrite, ammonium and in all of the three rivers water were in their normal range suggesting good water quality. Chrysophyta, Chlorophyta, Cyanophyta and Euglenophyta were respectively the most prevalent phytoplankton taxa and Zooplankton fauna of the rivers were fixed and sessile species belong to Protozoa and Rotatoria. 42 benthic macroinvertebrates taxa(Hevigh:36,Karkanrud:22 and Shafarud:30) were identified in these 3 rivers which individuals belong to order Diptera compromise the most divers and frequent one. Regarding macroinvertebrates diversity and indicator groups, it seems that Hevigh river has relatively better water quality than the two other. 23 fish species belong to 9 family,7 order and 2 class , were identified in these rivers during the study period which cyprinid were the most diverse and prevalent of them. Albornoides sp., Capoeta capoeta and Neogobios sp. were the most widespread and frequent species of the identified fishes in all of them. Bacteriological survey including Coliform and E.Colie count showed that the lower parts of the rivers near the estuaries were more infected and the bottom sediments had more bacterial count during the all sampling period. However the total coliform count never exceed of 200 colonies per 100cc , suggesting no risk for direct contact (swimming and washing), according to EPA standards. Chromium, Cadmium and Mercury had very low concentrations in the rivers water but Cupper had relatively high concentration (up to 1.788 mg/l in Hevigh river) amongst the studied heavy metals. The maximum and minimum concentrations of detergent materials or surfactant (LAS) were respectively observed in Shafarud (0.047 mg/l) and Hevigh (0.014 mg/l). According to the results of the study even though all the three rivers water had an overall reasonable quality, but some signs of destructions and degradations such as sedimentation, relatively increase of nutrient, increased concentrations of some pollutants, which all results in the low diversity of macroinvertebrates and prevents migration of anadromous fishes, calls for a continuing monitoring program and precise control for these regions

    Spin supercurrent in Josephson contacts with noncollinear ferromagnets

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    We present a theoretical study of the Josephson coupling of two s-wave superconductors which are connected through a diffusive contact consisting of noncollinear ferromagnetic domains. First, we consider a contact with two domains with magnetization vectors misoriented by an angle θ\theta. Using the quantum circuit theory, we find that in addition to the charge supercurrent, a spin supercurrent, which is even in ϕ\phi and odd in θ\theta, with a spin polarization normal to the magnetization vectors flows between the domains. Furthermore, with asymmetric insulating barriers at the interfaces of the junction, the system may experience an antiferromagnetic-ferromagnetic phase transition for ϕ=π\phi=\pi. Secondly, we discuss the spin supercurrent in an extended magnetic texture with multiple domainwalls. We find the position-dependent spin supercurrent. The magnitude of the spin supercurrent strongly depends on the phase difference between the superconductors and the number of domain walls. Our results demonstrate the possibility to couple the superconducting phase to the magnetization dynamics.Comment: 15 pages, 7 figure

    Evalution of genetic different between Litopenaeus vannamei of different race

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    In this study, after determining history of origin entering white leg shrimp of broodstocks at hatcheries of country, finally, two population of Molokaei and High health were considered as shrimp broodstocks of specific disease free (SPF) zero generation. After inbreeding and cross breeding among adult males and females of two population above, three storage different were produced in the first generation: H♂ × M♀, M♂ × H♀ and H♀ × H♂. The second generation were produced from selective breeding of M♂ × H♀. The aim of this study was to determine genetic differences between different generations of specific pathogenic free shrimp by evaluation of 16S rRNA region mitochondrial of different generations. Result of this study showed that of 486 sites have been identified 484 sites were conserved. Also, monomorphic sites ranged between 482 - 486 sites and was consists 2 polymorphic sites and 2 transitional sites. The number haplotypes, haplotypes diversity, nucleotide diversity revealed in this region were 2, 0.356±0.159 and 0.00147, respectively. Due to the high genetic identify and reduce of genetic distance of shrimp between different generations of SPF shrimp, genetic differentiation and gene flow (Nm) between them were -.142 and -2.00, respectively. This rates clearly shows a low level of polymorphism in this region of mitochondrial of different generation of SPF. This may be occurred because of small effective populations and genetic drift. Thus, offspring had inherited mitochondrial genome from your mother, therefore, it is expected that rate of variation in this genome is influenced by several factors, including genetic drift, due to unavailability of new-broodstock from different areas. It was observed that due to high conservation sites in 16S rRNA region of mitochondrial genome, nothing genetic differentiation was observed among different generations of SPF

    Possibility of using fresh water rotifer Brachionus calyciflorus for feeding Persian sturgeon Acipenser persicus

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    Acipenser persicus, one of the native Species living in the southern part of the Caspian Sea, has high Percentage of larval mortality. Therefor to decrease the rate of mortality of larvae survival and to increase to regenerate properly during the active feeding process of fish larvae, while under artificial reproduction they were fed withe fresh water rotifer. Four types of feeding treatments were applied as follow: Treatment 1: Similar to normal process, first withe Artemia cyst then withe Daphnia Treatment 2: Mixture of Artemia, Rotifer and Daphnia; Treatment 3 freshwater Rotifera ;Treatment 4: fresh water Rotifer enriched with Vitamin C (Ascorbic acid- 6- Palmytat).Three replicates were used for each treatment. In the process of each observation 45 larvae in containers withe 100 liter capacity filled with 30 liters of water, after 8 days of external feeding process, were inspected closely, during which , they were under biometric measurement once every two days. Larvae were fed Four times a day at a rate of 25% of their body weight. The average temperature estimation was 22.5±0.5 centigrade, pH .of water being 85±0.1 while Oxygen proved to be 9.58±0.2 mg/l. At the end of the observation, the profile fatty acids of the remains were studied. The growth factors, the mouth size of the larvae and the expansion of the mouth size compared to the total length of the larvae during the whole observation were inspected. Credibility of data designated was examined by Shapiro Wilks test. Specific growth rate (SGR), weight growth (WG) and feed conversion ratio (FCR) were contemplated by one-way analysis test, and significant difference Tukey's test. The most notable diversity was evident between treatment 2, whose indicative factors were in the following order: 4.65± 0.06, 45.18±0.66, 4/48 ± 0/07 and treatment 4 whose indicative factors showed the following results: 10.47±0.04, 124.42±0.62, 1.51±0/008.For the determination of fatness rate and weight gains, Kruskal Valis and Man vit ni test were used .In this part of study , the highest diversity fatness appeared to be between treatment 4 ,reflecting 0.79±0.07 and treatment 2 showing the result 0.62±0.05.The highest gain was related to treatment 4, whit the rate of 99.33±0/68 mgr and the lowest gain occurred in treatment 2 white the rate 62.36 ± 0.65 mgr. This study also revealed that, the survival ratio connected with treatments 3 and 4, compared treatments 1 and 2, were significantly different. The profile of fatty acids also showed much higher percentage of PUFA and HUFA in treatments 3 and 4, than those in other treatments. Furthermore Brachionus calyciflorus proved to be a proper food supply for larvae. Therefore by building suitable pools next to the work side, other kinds of species fresh water rotifer could also be used as food improvements for feeding larvae

    Synergistic effects of melatonin and gamma-aminobutyric acid on protection of photosynthesis system in response to multiple abiotic stressors

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    GABA (gamma-aminobutyric acid) and melatonin are endogenous compounds that enhance plant responses to abiotic stresses. The response of Vicia faba to different stressors (salinity (NaCl), poly ethylene glycol (PEG), and sulfur dioxide (SO2)) was studied after priming with sole application of GABA and melatonin or their co-application (GABA + melatonin). Both melatonin and GABA and their co-application increased leaf area, number of flowers, shoot dry and fresh weight, and total biomass. Plants treated with GABA, melatonin, and GABA + melatonin developed larger stomata with wider aperture compared to the stomata of control plants. The functionality of the photosynthetic system was improved in primed plants. To investigate the photosynthetic functionality in details, the leaf samples of primed plants were exposed to different stressors, including SO2, PEG, and NaCl. The maximum quantum yield of photosystem II (PS II) was higher in the leaf samples of primed plants, while the non-photochemical quenching (NPQ) of primed plants was decreased when leaf samples were exposed to the stressors. Correlation analysis showed the association of initial PIabs with post-stress FV/FM and NPQ. Stressors attenuated the association of initial PIabs with both FV/FM and NPQ, while priming plants with GABA, melatonin, or GABA + melatonin minimized the effect of stressors by attenuating these correlations. In conclusion, priming plants with both GABA and melatonin improved growth and photosynthetic performance of Vicia faba and mitigated the effects of abiotic stressors on the photosynthetic performance

    Stock assessment of bonyfishes in the Iranian coastal water of the Caspian Sea (2004-2005)

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    For gathering of data on biometry and catch statistics, 5 mobile working group in the regions of Anzali, Kiashahr , Noshahr , Babolsar and Torkmen were involved from the start (2004.10.23) to the end of fishing season (2005.04.10). Gathered data were entered to the computer based on species. For data analysis different methods were undertaken such as Bertallanfy equation for growth parameter Beverton and Holt for total mortality rates, pauly's imperical model for natural mortality rate and cohort Analysis for biomass estimation. Total catch with taking into account of poaching, was estimated 15140 tons reported by scientific committee of catch and fishing harbor relief of Iranian Fishery Company. The total recorded catch of beach seine cooperatives was 10644 tons that comprise 70.2% of the total catch. Total catch of Caspian Kutum was estimated 6612 tons that had 1856 tons (22%) decrease with comparison of the last year. Biomass of Caspian kutum in Iranian coastal Water of the Caspian Sea in 2003-2004 estimated about 20400 tons. The total catch of golden gray mullet was estimated 4425.6 tons that constitute 29.2% of total catch of bony fishes. Biomass of this species was estimated 12200 tons and based on this amount of biomass, Maximum Sustainable Yield (MSY) was calculated as 3577 tons. Long nose mullet comprised only 1.4% of the mullet catch. The catch of common carp in 2004-2005 fishing season continued its increasing trend and caught in amount of 3087 tons by beach seine cooperatives that had 2.2 fold increase in comparison of previous fishing season. Most of the catch occurred in Golestan province and was immature and undersize and the length frequency modes showed moving towards bigger size and older age groups in comparison of previous fishing season. The catch of pick perch in 2003-2004 decreased with comparison of the last year and estimated about 22.5 tons. Most of the catch of pick perch was immature and undersize. Approximately all of the catch is due to releasing of fingerling of this species by Fishery Company especially in Guilan province. Total catch of bream was estimated 27.4 tons and most of which was immature and undersize. Population of asp is critically endangered and the catch of this species is very low (500 kg). Restocking of this species must be considered by Iranian fishing company

    Development and potential role of type-2 sodium-glucose transporter inhibitors for management of type 2 diabetes

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    There is a recognized need for new treatment options for type 2 diabetes mellitus (T2DM). Recovery of glucose from the glomerular filtrate represents an important mechanism in maintaining glucose homeostasis and represents a novel target for the management of T2DM. Recovery of glucose from the glomerular filtrate is executed principally by the type 2 sodium-glucose cotransporter (SGLT2). Inhibition of SGLT2 promotes glucose excretion and normalizes glycemia in animal models. First reports of specifically designed SGLT2 inhibitors began to appear in the second half of the 1990s. Several candidate SGLT2 inhibitors are currently under development, with four in the later stages of clinical testing. The safety profile of SGLT2 inhibitors is expected to be good, as their target is a highly specific membrane transporter expressed almost exclusively within the renal tubules. One safety concern is that of glycosuria, which could predispose patients to increased urinary tract infections. So far the reported safety profile of SGLT2 inhibitors in clinical studies appears to confirm that the class is well tolerated. Where SGLT2 inhibitors will fit in the current cascade of treatments for T2DM has yet to be established. The expected favorable safety profile and insulin-independent mechanism of action appear to support their use in combination with other antidiabetic drugs. Promotion of glucose excretion introduces the opportunity to clear calories (80–90 g [300–400 calories] of glucose per day) in patients that are generally overweight, and is expected to work synergistically with weight reduction programs. Experience will most likely lead to better understanding of which patients are likely to respond best to SGLT2 inhibitors, and under what circumstances

    Spin-polarized supercurrents for spintronics: a review of current progress

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    During the past 15 years a new field has emerged, which combines superconductivity and spintronics, with the goal to pave a way for new types of devices for applications combining the virtues of both by offering the possibility of long-range spin-polarized supercurrents. Such supercurrents constitute a fruitful basis for the study of fundamental physics as they combine macroscopic quantum coherence with microscopic exchange interactions, spin selectivity, and spin transport. This report follows recent developments in the controlled creation of long-range equal-spin triplet supercurrents in ferromagnets and its contribution to spintronics. The mutual proximity-induced modification of order in superconductor-ferromagnet hybrid structures introduces in a natural way such evasive phenomena as triplet superconductivity, odd-frequency pairing, Fulde-Ferrell-Larkin-Ovchinnikov pairing, long-range equal-spin supercurrents, π\pi-Josephson junctions, as well as long-range magnetic proximity effects. All these effects were rather exotic before 2000, when improvements in nanofabrication and materials control allowed for a new quality of hybrid structures. Guided by pioneering theoretical studies, experimental progress evolved rapidly, and since 2010 triplet supercurrents are routinely produced and observed. We have entered a new stage of studying new phases of matter previously out of our reach, and of merging the hitherto disparate fields of superconductivity and spintronics to a new research direction: super-spintronics.Comment: 95 pages, 23 Figures; published version with minor typos corrected and few references adde

    The study of establishment of rainbow trout culture and hatchery farms on Zayanderood’s River region in Caharmahal and Bakhtiyari Province

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    The aim of this study was to find the best location for establishment of rainbow trout culture and hatcheries farms on Zayanderood’s river region in Charmahal and Bakhtiyari province. This survey carried out over ten station along Zayanderood’s river. The result of physical and chemical analysis showd that the annual average of air temperature varied from 9.5oC - 10oC where the pH annual average value were between 7.5 and 8.8. the dissolve oxygen concentration in stations except in rainbow trout farm effluent were above 10 mg/l. the other chemical , pollutant as well as pesticides levels were under the limiting concentration for rainbow trout culture and Hatcheries activity. The plankton survey showed that the Bacillurophyta were the dominant group of phytoplankton where protozoa constituted the most abundant group of zooplankton the Benthic organisms sensitive to pollutant in particular Epirus were dominant group in all stations. In regard to fishes presence in river, five species of Ciprinidae, one species from Balitoridae and one species from salmonidae families were identified. The capacity for development of rainbow trout culture for tow phase period in Zayanderood’s river region with respect to self purification potential (self purification potential were determined from the oxidation of the effluent of the only active trout farm of the river region), minimum of 10 L/s water requirement for production of trout in concrete canal and pond system and 1 L/S water need for production in semi circular closed system were estimated to be 5202 metric tons
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