Population dynamics of Barbus grypus (Heckel, 1843) and Barbus barbulus (Heckel, 1847) in Karoon River, south-west Iran

Barbus sp. fish samples were collected during November 2007 to October 2008 from five landing stations in Karoon River: Gotvand, Shoshtar, Molasani, Ahwaz, and Darkhoin. During one year of study, more than 2000 specimens of B. grypus and B. barbulus were measured, mean±SD length values for this species were 37.94±8.18 and 43.62±10.27, respectively and maximum and minimum total length were 20-76cm and 20-94cm, respectively. Mean±SD of weight values for this species were 873.2±1092.45 grams and 778.59±725.97 grams, respectively and maximum and minimum weight were 52-11170 grams and 52-4675 grams, respectively. Growth and mortality parameters were calculated for B. grypus and B. barbulus as L∞: 86.64, 132.9 and K: 0.27, 0.17 and t0: -0.46, -0.66, M: 0.50, 0.33, F: 1.22, 1.04, Z: 1.72, 2.72, 'Ф: 3.31, 3.48, E: 0.71, 0.76, respectively. According to the exploitation coefficient, B. grypus and B. barbulus stocks are overfished; hence we suggest a decrease in exploitation coefficient. Based on results and their comparison with the American Fisheries Society (AFS) indices, these species are classified in moderate to high vulnerable group fishes

Population biology and assessment of Kawakawa (Euthynnus affinis) in coastal waters of the Persian Gulf and Sea of Oman (Hormozgan Province)

Length composition data (fork length) of kawakawa (Euthynnus affinis ), landed between April 2003 to March 2005 in Coastal Waters of Hormozgan province in Iran ( Persian Gulf and Sea of Oman) , were monthly used to estimate the p opulation parameters and for the assessment of the stock. The growth parameters of von Bertalanffy equation were estimated as L∞: 87.66 cm, K: 0.51 per year and t0: -0.23 year. The estimated value of total mortality, natural mortality and fishing mortality were Z: 2.37, M: 0.65, F: 1.72 per year, respectively. Exploitation ratio (E) and Exploitation rate (U) were estimated as 0.72 and 0.65. The Annual total stock at beginning of year was calculated to be 7924 t and Annual average standing stock (S) was equal to 2994 t. By using analyses knife-edge selection method, biological reference points for kawakawa stock was calculated as, Y'/R (relative yield per recruitment) =0.062, B'/R (relative biomass per recruitment) =0.13, F max (Fishing mortality at maximum sustainable yield) =1.6, E max (Exploitation ratio at maximum sustainable yield) = 0.68 Fopt (Precautionary average target ) =0.33 year-1 and Flimit=0.43 year-1. As the exploitation ratio of kawakawa stock in this study was calculated to be over 0.5, it strongly recommended minimizing the fishing activity in this area

Evaluation of effects of physico-chemical factors on chlorophyll-a in Shadegan International Wetland - Khouzestan Province - Iran

Measurement of chlorophyll-a can be considered important to investigate the primary production of an ecosystem. This study aimed to investigate chlorophyll-a concentration, primary production and the factors affecting them in Shadegan Wetland located in Khouzestan Province - Iran. Sampling for measuring (NO3, PO4, BOD5, DO, pH, EC, salinity, temperature) was performed seasonally at five sampling stations of the wetland (Canal, Ragbeh, Khoroosi, Mahshahr and Atish), from March 2013 – through February 2014. Results showed that chlorophyll-a concentrations in Canal station were significantly higher than that in the other stations; however, there were no significant differences among the other sampling stations (p>0.05). The maximum and minimum primary production (and chlorophyll-a) (62, 1.14 mg/m^3) were observed at Canal and Ragbeh stations, respectively. Annual average chlorophyll-a concentration was 10.28 mg/m^3, and there was no significant seasonal difference (p>0.05). The maximum value of chlorophyll-a was observed in the fall (29.63 mg/m^3), whereas, the minimum value was related to the spring (4.07 mg/m^3). Among the water physicochemical parameters, nitrate had a significant effect on chlorophyll-a concentrations. According to trophic state index (TSI), Shadegan Wetland is mesotrophic in the spring and winter, whereas it is eutrophic in the summer and fall. Overall, the lake is suitable for warm water species

Estimation of dosimetric parameters based on K nr and K ncsf correction factors for small field radiation therapy at 6 and 18 MV linac energies using monte carlo simulation methods

Background: Estimating dosimetric parameters for small fields under non-reference conditions leads to significant errors if done based on conventional protocols used for large fields in reference conditions. Hence, further correction factors have been introduced to take into account the influence of spectral quality changes when various detectors are used in non-reference conditions at different depths and field sizes. Objective: Determining correction factors (K NR and K NCSF ) recommended recently for small field dosimetry formalism by American Association of Physicists in Medicine (AAPM) for different detectors at 6 and 18 MV photon beams. Methods: EGSnrc Monte Carlo code was used to calculate the doses measured with different detectors located in a slab phantom and the recommended K NR and K NCSF correction factors for various circular small field sizes ranging from 5-30 mm diameters. K NR and K NCSF correction factors were determined for different active detectors (a pinpoint chamber, EDP-20 and EDP-10 diodes) in a homogeneous phantom irradiated to 6 and 18 MV photon beams of a Varian linac (2100C/D). Results: K NR correction factor estimated for the highest small circular field size of 30 mm diameter for the pinpoint chamber, EDP-20 and EDP-10 diodes were 0.993, 1.020 and 1.054; and 0.992, 1.054 and 1.005 for the 6 and 18 MV beams, respectively. The K NCSF correction factor estimated for the lowest circular field size of 5 mm for the pinpoint chamber, EDP-20 and EDP-10 diodes were 0.994, 1.023, and 1.040; and 1.000, 1.014, and 1.022 for the 6 and 18 MV photon beams, respectively. Conclusion: Comparing the results obtained for the detectors used in this study reveals that the unshielded diodes (EDP-20 and EDP-10) can confidently be recommended for small field dosimetry as their correction factors (K NR and K NCSF ) was close to 1.0 for all small field sizes investigated and are mainly independent from the electron beam spot size. © 2019, Shiraz University of Medical Sciences. All rights reserved

Investigation of temperature and residual stresses field of submerged arc welding by finite element method and experiments

This article reports on a numerical and experimental investigation to understand and improve computer methods in application of the Goldak model for predicting thermal distribution in submerged arc welding (SAW) of APIX65 pipeline steel. Accurate prediction of the thermal cycle and residual stresses will enable control of the fusion zone geometry, microstructure, and mechanical properties of the SAW joint. In this study, a new Goldak heat source distribution model for SAW is presented first. Both 2D and 3D finite element models are developed using the solution of heat transfer equations in ABAQUS Standard implicit. The obtained results proved that the 2D axi-symmetric model can be effectively employed to simulate the thermal cycles and the welding residual stresses for the test steel. As compared to the 3D analysis, the 2D model significantly reduced the time and cost of the FE computation. The numerical accuracy of the predicted fusion zone geometry is compared to the experimentally obtained values for bead-on-plate welds. The predictions given by the present model were found to be in good agreement with experimental measurements

Scleral buckling surgery for rhegmatogenous retinal detachment with subretinal proliferation

PurposeTo evaluate the outcome of scleral buckling surgery in patients with rhegmatogenous retinal detachment (RRD) with subretinal proliferation.MethodsIn this retrospective study, a chart review of all patients with RRD associated with subretinal proliferation who were primarily treated with scleral buckling procedure, from April 2007 to April 2014, was undertaken. Main outcome measures were anatomical retinal reattachment and visual acuity.ResultsForty-four eyes of 43 patients including 24 males and 19 females with a mean age of 26.5±13.1 years were evaluated. Immediately after the surgery, retina was reattached in all eyes. However, five eyes (11.3) needed additional surgery for retinal redetachment. Single surgery anatomical success rate was 88.7. Four eyes (9.1), needed pars plana vitrectomy for the treatment of redetachment associated with proliferative vitreoretinopathy and scleral buckle revision surgery was successfully performed in the other eye. Best corrected visual acuity improved from 1.5±0.9 logMAR before surgery to 1.1±0.7 logMAR after surgery (P2 lines was found in 23 eyes (52.2) and worsening of best corrected visual acuity of >2 lines was observed in 2 eyes (4.5).ConclusionsScleral buckling surgery is highly successful in eyes with RRD associated with subretinal proliferation. © 2015 Macmillan Publishers Limited All rights reserved

Effect of Cyperus rotundus on ischemia-induced brain damage and memory dysfunction in rats

Objective(s): Global cerebral ischemia-reperfusion injury causes loss of pyramidal cells in CA1 region of hippocampus. In this study, we investigated the possible neuroprotective effects of the ethanol extract of Cyperus rotundus (EECR) on a model of global transient ischemia in rat, by evaluating the pathophysiology of the hippocampal tissue and spatial memory. Materials and Methods: Treatment group (EECR, 100 mg/kg/day) was gavaged from 4 days before, to 3 days after ischemia. Morris water maze test was performed 1 week after ischemia for 4 days. Brain tissue was prepared for Nissl staining. Results: Our data showed no statistical difference between the treatment and ischemia groups in water maze task. So, treatment of ischemia with EECR cannot improve spatial learning and memory. On the contrary EECR ameliorated the CA1 pyramidal cell loss due to transient global ischemia/ reperfusion injury. Conclusion: These results suggest that EECR cannot reduce the ischemia-induced, cognitive impairments seen after transient, global cerebral ischemia but can prevent pyramidal cell loss in CA1 region of hippocampus. © 2015, Mashhad University of Medical Sciences. All rights reserved

Evaluation of the large pelagic fishes (Scomberidae family) for optimum exploitation level in the Persian Gulf

Reproductive biology, Diet and population dynamics parameters of narrow-barred Spanish mackerel, Scomberomorus commerson, in the Persian Gulf were studied during 2011-2012. Fork length frequencies were collected from the commercial catch and from the current fishery nets (gill nets with 9 and 14cm mesh size) at the landing places. During 5 periods in October, December, March, April and July 20-40 specimens were also purchased from the fishermen at several landing sites to investigate and recording of data for feeding and reproductive conditions. Fork length (FL) of 2742 fishes was recorded to the nearest cm and weight of the specimens were measured to the nearest 0.01kg. FiSAT program was used to assess growth and mortality parameters. Reproductive maturity stages were assessed macroscopically using a five element scheme based on gonad size and appearance. The numbers of ovaries were fixed and preserved in 10% formalin. Central sections were embedded in wax, sectioned Hematoxylin–Eosin stains. For this subset, gonad maturation was categorized histological using a simplified five-stage description scheme and compared with the macroscopic assessments for validation. A Gonosomatic index (GSI) was also calculated for each fish. Feeding condition results showed that, sardines are the major prey of S. commerson. Pony fishes, Haltbeak and Indian mackerel were observed in the stomach content. These preys can be assumed as a secondary or accidental food items. Liver Somatic Index (HSI) was maximum in April and minimum in July. The annual instantaneous rate of fishing mortality (F= 0.42 year^−1) was considerably greater than the target (Fopt= 0.28) and limit (Flimit= 0.37) biological reference points, suggesting that the stock is heavily overexploited. Feeding and nutrition results showed that sardines are the major items prey of king S. commerson. Ponyfish, haltbeak and Indian mackerel fishes were observed in diet that can be considered as secondary or accidental foods. Maximum and minimum of Kn index was in October (9.3) and in March respectively. Liver Somatic Index (HSI) was the highest rate in February (1.70) and the lowest in July (0.85) that indicated on the worst and the best condition of fish in the mentioned periods respectively. No difference was observed in the weight stomach index and weight index (SI) in two sexes and it was about 0.09. The smallest of fish was observed 17cm FL and the biggest was 152cm FL. The mean size of fork length frequency was observed from maximum108cm (SD= 24) in February to minimum 29.4cm (SD= 5.5) in September. Based on growth curve analysis, growth parameters, K and L_∞ were estimated 0.23year^−1 and 156.45 cm respectively. Instantaneous total mortality (Z), was 1.13 year^−1 . The estimate of M was 0.43 year^−1 and thus, the estimate of F was0.7 year^−1 . This translates to an exploitation rate (F/Z) of 0.69 year^−1 . Target (Fopt) and limit (Flimit) biological reference points were calculated 0.17 year^−1 and 0.22 year^−1 respectively. The size at capture at a probability of 0.25 (L25), 0.5 (L.5) and 0.75 (L.75) was35.84 cm, 40.28cm and 61.98 cm respectively. Tmax was calculated as 3/K equal to 6 years. Matured females (Stages III, IV) were observed between mostly between April to July. By July, most fishes were in ripped and spent stages (StagesIV, V) indicating the end of the spawning season. The result of GSI avtivity in 153 male and female fish indicated the highest reproductive activity from April to July with the peak of July. The present study results shows that the highest of catch rate were done in 1 and 2 years olds of fish. Although exploitation rate have not indicated over fishing but Fopt and Flimit rates are less than fishing mortality that shows overexploitation was happened. Changes of the mesh size in the gillnet of 9cm and the size of the nets should be considered. Banning of the king mackerel catch in the June and July that is the spawning peak period can be helped to the brood stocks

Status of the tiger tooth croaker, Otolithes ruber (Schneider, 1801) and jinga shrimp, Metapenaeus affinis(H. Milne Edwards, 1837) stocks in Khouzestan coastal waters

Population dynamics parameters and exploitation ratio of Jinga Shrimp, Metapenaeus affinis were studied from Sep 2011 to Dec 2011 and data collected from two landing places (Hendijan and Lifee-Bosif). During the project, more than 2200 specimens of jinga shrimp were measured. The mean value of length for the male and female were calculated as 9.8±0.86, 10.24±1.18 and mean value of weight for the male and female was as 6.730±1.64, 8.14±2.90 respectively. The length-weight relation were calculated as TW=0.024TL2.24 (n=1084,R^2=0.71) for males, TW=0.011TL2.80 (n=1081,R^2= 0.81) for females also we found significant different level length-weight relation in P<0.05. The growth parameters of von Bertalanffy equation were as, L_∞: 14.73 and K: 1.1 and t0: -0.02. The estimated valve of total mortality, natural mortality, fishing mortality and exploitation ratio is Z: 4.35, M: 1.68, F: 2.67, E: 0.61 respectively. By using method analyses knife-edge selection, relative yield per recruitment (Y'/R) :0.014, relative biomass per recruitment, (B'/R) :0.085., Exploitation ratio maximum sustainable yield, Emax : 0.38; biological reference points for Jinga Shrimp stock was calculated. MSY and fmsy value was 600T and 46100day respectively. Result in this study showed exploitation ratio Jinga Shrimp stock is over fishing and decreases exploitation ratio proposed