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Showing 13 results for Growth Rate

Omidvar Farhadian, Seyed Mojtaba Fallahi, Nasrollah Mahboobi Soofiani,
Volume 1, Issue 1 (3-2013)
Abstract

In order to determine effects of chicken and cattle manures in culture of Chlorococcum, an experiment was designed in six treatments including; 0.1, 0.4, 0.8 g/l of chicken manure and 0.1, 0.4, 0.8 g/l of cattle manure as completely randomize design with three replicates for 28 days. Results showed that the mean maximum density (87.1 × 105 cell/ml), specific growth rate (0.054 day-1), algal dry biomass (0.644 g/l), and chlorophyll a (9.42 mg/l) were obtained with 0.8 mg/l chicken manure. In order to compare performance of these manures with other culture media, second experiment with five treatments including; BBM (control) (Bold’s Basal Medium), BBM + soil extract, 0.8 g/l chicken manure, 0.8 g/l cattle manure and mixture of all treatment (BBM, BBM + soil extract, chicken manure and cattle manure) was designed as completely randomize design with three replicates for 15 days. Comparative results showed that BBM + soil extract had highest algal density (11.6 x 106 cells/ml), highest algal dry biomass (0.81 mg/ml), maximum SGR (0.13 /day), highest chlorophyll a (10.15 mg/l) and minimum doubling time (4.97 days). In conclusion, performance of BBM + soil extract was better in terms of biomass and growth parameters of Chlorococcum.
Masoumeh Pourafrasiabi, Zohreh Ramezanpour, Javid Imanpour Namin, Marjan Sadeghi Rad,
Volume 2, Issue 1 (6-2013)
Abstract

Cell concentrations and growth rate of Dunaliella salina Teodoresco in light intensities e. g. 50 and 150 µmol. photons.m-2.s-1 and temperatures 25 ± 0.5 and 31 ± 0.5 oC (Mean ± SD) were studied. The algae was isolated from the Urumieh Lake and cultured in various treatments (n=12). Algae cells were counted regularly using Thoma counting chamber in 3 replicates on daily basis. The curve of changes in population was plotted. The specific growth rate (SGR; d-1) was calculated and compared within treatments by means of two ways ANOVA Analysis. The highest cell concentration (Mean ± SD) 4.8 ± 0.6 × 10 6 cell.ml-1 was observed in light intensity of 150 µmol. photons.m-2.s-1 and temperature 25 ± 0.5 oC. The minimum cell concentration (2.8 ± 0.3 × 10 6 cell.ml-1) was observed in light intensity of 50 µmol. photons.m-2.s-1 and temperature 31 ± 0.5 oC. Specific growth rate showed significant differences in various treatments (P

Volume 2, Issue 1 (9-2011)
Abstract

Abstract: In recent years, extension of Artemia applications in aquaculture and decreasing of natural resource, lead many of related studies to the distribution of Artemia population and new resource assessment studies. Urmia Lake as one the biggest habitat for Artemia because of ecological variations in the regions in which of its differentiations in cyst biometry and Artemia, moreover some genetic variations suggested to have some several Artemia populations in the Lake. In this project Artemia cyst samples were collected from 5 ecological stations of the Lake Urmia. The cyst hatching and the nauplii breeding up to adult Artemia stage were done according to optimum conditions in laboratory. Growth rate and survival of larva in days of 3, 5, 7, 11, 15, 20 of rearing period were measured in feeding with a complex of Dunaliella tertiolecta and Lanzy PZ for a period of 20 days in 75 and 150 ppt. Data and its statistical analysis revealed that according to previously records the growth rate of the Artemia was influenced by increasing the salinity from 75 to 150 ppt survival and growth rate of Artemia have been influenced by water salinity (P<0.05) but increasing the salinity only in two population of Bari and Eslami led decreasing of survival. The produced cysts in two salinity showed that Artemia population can produce the cysts with different diameter and there were not any statistic correlations between the salinity and populations. The Dandrogarm of population statistic analysis emphasized that according to growth rate and survival parameters and among populations under this test there were 4 different populations of Artemia urmiana in which had interesting differentiations in growth rate and survival. Keywords: Artemia, Survival, Growth rate, Salinity, Urmia Lake.
Elham Dehghan, Abdolsamad Keramat, Hossein Oraji, Khosro Jani Khalili,
Volume 4, Issue 1 (6-2015)
Abstract

The present study was to evaluate the impact of feeding level and fish size on the growth factors,carcass composition and digestibility of rainbow trout. Six experimental treatments were assigned by the use of three feeding levels (maintenance, medium and satiation levels) and two fish sizes (43.02 ± 2.93 and 231.32± 6.74g) according to a 3×2 factorial design.  There were three replicates for each treatment and the experiment lasted for 59 days. The results showed that there is a significant interaction effect between fish size and feeding level for body weight gain, final body weight and specific growth (p<0.05). Body composition (dry matter, energy, moisture, fat and protein) was affected by feeding level and size of the fish (p<0.05). However, the interaction effect between fish size and feeding level for body composition was not significant (p>0.05).The digestibility measurements showed that fish size and feeding level  changed  significantly digestibility of protein, lipid, energy and dry matter in rainbow trout (p<0.05). Maximum growth at satiation feeding level can reduce feed conversion ratio and increase waste production at both fish sizes.

Volume 4, Issue 4 (12-2015)
Abstract

Control of stored-product insect by gamma radiation could be enhanced by other possible techniques such as essential oils as effective alternatives to chemical insecticides. In this study, the efficiency of gamma radiation combined with Perovskia atriplicifolia (Benth) was verified to assess their enhanced antifeedant effect against the Tribolium castaneum (Herbst). Flour disc bioassay was employed to assess the nutritional indices, such as relative growth rate (RGR), relative consumption rate (RCR), efficiency of conversion ingested food (ECI) and feeding deterrence index (FDI). The results showed that irradiation, essential oil and combination of both of them significantly reduced RGR, RCR and ECI in treated larvae and adults. As irradiation at 100 Gy reduced RGR of the larvae and adults from 0.0884 and 0.0366 to 0.0596 and 0.0332 mg/mg/day respectively, when combined with doses of P. atriplicifolia essential oil, the reduction reached to 0.051 - 0.388 and 0.01- 0.224 mg/mg/day respectively. The reduction rates in larvae were even greater when combination of irradiation and EO treatments were used. The results showed a significant increase in the feeding deterrence due to irradiation, essential oil and specially their combination. Therefore, findings led to a conclusion that irradiation can enhance antifeedant activity of essential oils.

Volume 5, Issue 3 (9-2016)
Abstract

In this study, the efficiency of essential oils from asafoetida, Ferula assa foetida L.,geranium, Pelargonium hortorum L.H. Bailey and walnut leaves, Juglans regia F. was investigated on nutritional indices of Rhyzopertha dominica (F.) adults. Wheat grains were treated with different concentrations of the oils. The nutritional indices: relative growth rate (RGR), relative consumption rate (RCR), efficiency of conversion of ingested food (ECI) and feeding deterrence index (FDI) were measured at 28 ± 2 °C, 65 ± 5% R. H. in continuous darkness. RGR, RCR and ECI deceased as the concentration level was increased. While, FDI percent increased significantly as the concentration level increased. Asafoetida oil had the most efficiency on nutritional indices and 28.61 ppm of the oil was enough to decrease RGR, RCR and ECI% to 0.032 mg/mg/day, 0.444 mg/mg/day and 6.994%, respectively. FDI percent of adults exposed to 6.5 ppm of asafoetida oil was 13.31% which increased upto 64.62% at the concentration of 28.61 ppm. In the second experiment, the effect of tested essential oils was evaluated on F1 progeny reduction of R. dominica. Walnut and asafoetida leaves essential oils significantly suppressed progeny production by (59.92%) and (53.2%) respectively.
 
M. Fallahi Kapourchali , Sh. Rahbary , M. Shamsaei,
Volume 7, Issue 2 (6-2018)
Abstract

Aims: The aim of this study was to investigate the effect of Diuron in vitro on the growth rate of Anabaena flos-aquae in order to determine the toxicity of diuron by calculating EC10, EC50, EC90, and MAC value for this alga to control flourishing in this phytoplankton.
Materials and Methods: In this experimental research, the growth rate of Anabaena flos-aquae was investigated under the influence of diuron. This experiment was conducted in 96 days with 6 treatments (0.0005, 0.009, 0.016, 0.03, 0.054, and 0.01 mg/l), 1 control group, and 3 repetitions of the treatments in 500cc Erlenmeyer flasks. The growth rate was measured, using cell counting, turbidimetric measurement, and chlorophyll a measurement methods. Then, achieved quantities of EC were used in four 500cc Erlenmeyer flasks and the concentration of algae was evaluated through cell counting in 24-hours periods during 96 hours. Using SPSS 17 software, one-way ANOVA was used to compare the increase percentages between different treatments.
Findings: Quantities of EC10, EC50, EC90, and Mac value of this toxicant for the algae according to chlorophyll a concentration were reported 0.006, 0.01, 0.05, and 0.001 mg/l, respectively. The frequency of Anabaena flos-aquae was significantly different in presence of concentrations obtained from EC indices and decreased sharply in EC90 quantities.
Conclusion: The use of diuron in the proposed concentrations reduces its risk from the perspective of toxicity and contamination of other components of the ecosystem and it is more effective in this group of algae.


Volume 11, Issue 1 (1-2022)
Abstract

Downy mildew is one of the most important diseases of cucurbits in the world and Iran. The development of the disease was investigated in a commercial variety (Sakata® F1 Hybrid Saso), three hybrids and eight pure lines of cucumber, four pure squash lines, and one commercial cultivar of watermelon (Sakata® F1 Charleston Gray 243) in two consecutive years (2017 and 2018 spring and summer) at the experimental field of the University of Guilan, Iran to identify the sources of resistance. Plants were regularly inspected until the downy mildew symptoms appeared. The disease was measured using standard scale and Image J software at five stages in the plant growing season. Comparison of disease progress curves, final severity of the disease, and area under the disease progress curve (AUDPC) showed that cucumber B10 and A12 pure lines were the most susceptible and resistant in both years, respectively. None of the squash lines were infected in the first year, but in the second year, two lines showed the disease symptoms, and the severity of the disease in these lines was close to each other. The commercial cultivar of watermelon was not infected in both years.



Volume 11, Issue 2 (6-2020)
Abstract

In this study, the effect of red and blue illumination on continuous culture of two different species of microalgae and cynicocytosis was studied. Comparison of blue and red lights in the cyanobacteria, Synechocystis sp. PCC6803, showed that this specie grows very fast under red light illumination, but it has very slow growth rate under blue light exposure. In spite of huge difference in growth rate, the lipid content and the fatty acid composition of Synechocystis was approximately the same for red and blue light illumination. For microalgae, Chlorella Sorokiniana, the blue light resulted to slightly higher growth rate than the red light. The C18:3 unsaturated fatty acid content was significantly higher for red light illumination compare to blue light illumination. Overall, considering the lower energy requirement for illumination of red, this light is more efficient than blue light for cultivation of Chlorella Sorokiniana.

Volume 17, Issue 6 (11-2015)
Abstract

Aphids in unsprayed canola (Brassica napus Linnaeus) fields in Isfahan province (central Iran) were sampled for two growing seasons, 2011-2013. Sampling unit was a whole plant and 20 plants were sampled weekly. In the laboratory, heat-extracting and sub-sampling techniques were used to estimate the density of aphids. To determine the relationship between population growth rate of the aphids and degree-days,linear regressions were done between log of aphid density and accumulated degree-days. Homogeneity tests were done using pairwise comparisons between slopes. Aphids' preference for upper (10-15 cm upper part of stem) and lower (the rest of stem) parts of the plant was analyzed using Student’s t-test. Aphid fauna included: Cabbage Aphid [CA; Brevicoryne brassicae (L.)], Green Peach Aphid [GPA; Myzus persicae (Sulzer)], and Turnip Aphid [TA; Lipaphis erysimi (Kaltenbach)]. The GPA developed small population in comparison with CA and TA and was occasionally found. The population density of CA and GPA tended to show two peaks and, during flower initiation, population began to decrease. The average population growth rates of GPA and CA were 0.001 and 0.003, respectively. Homogeneity tests indicated that, at all sites and years, GPA showed reduced growth rate compared to CA. On average, 36 and 64% of CA and GPA populations were found on the lower parts of plants, respectively. This indicated that CA preferred upper part while GPA preferred lower part of the plants. The obtained results could be used to make a contribution to systematize the field monitoring of predominant aphids in canola crop.

Volume 17, Issue 11 (1-2018)
Abstract

Compressor and their blades are one of the most important parts of gas turbines. Based on recent reports, failure of compressor’s blades was one of the major cause in malfunctioned t56 gas turbines. In this study, propagation rate of a crack within the compressor blade of a T56 jet engine has been investigated. To this end, centrifugal and aerodynamic forces acted upon the blade has been calculated and their corresponding stress field has been simulated in ANSYS software. Spots at the maximum risk of foreign object damage and corrosion had been located, and their bending and tension stresses had been calculated via employed simulation. Subsequently, an initial half elliptical crack has been created on all of previously located spots, and their stress intensity factor using Raju-Newman method has been determined. Finally, by using Paris law fatigue life and crack growth rate of each cracks has been extracted, individually. Results indicate a drastic decrease in fatigue life of blades when crack located close to the blade’s root. Furthermore, cracks located on the suction surface has remarkably shorter fatigue life than those which are located on pressure surface, in comparison.

Volume 20, Issue 1 (1-2018)
Abstract

In this study, the nutritional indices of the larval stages of Helicoverpa armigera (Hübner) were determined on 10 canola (Brassica napus L.) genotypes (Talaye, Opera, Licord, Modena, SLM046, Hayula420, Zarfam, Okapi, RGS003 and Sarigol) at 25±1˚C, 60±5% RH and a photoperiod of 16: 8 (L: D) hours. The third instar larvae reared on Talaye showed the highest value of Efficiency of Conversion of Ingested food ECI and Efficiency of Conversion of Digested food ECD (7.005±0.632 and 8.972±1.862, respectively). However, the lowest value of ECI and ECD was on Licord (0.503±0.017 and 2.507±0.449, respectively). The highest (0.778±0.091) and lowest (0.594±0.059) Relative Growth Rate (RGR) of the fourth instar larvae were obtained on SLM046 and Sarigol, respectively. Results indicated that the highest values of ECI and ECD for fourth instar larvae were on Talaye (6.300±0.585 and 8.880±1.954, respectively). The lowest value of the Relative Consumption Rate (RCR) and Approximate Digestibility (AD) of the fifth instar was recorded on Modena (5.193±0.629 and 38.625±11.340, respectively). The ECI and ECD values of the fifth larval instar were the highest on Talaye (9.893±0.889 and 19.655±0.966, respectively). The highest value of RCR and AD of the sixth instar was on Okapi (7.781±0.665 and 82.223±1.922, respectively). Among different genotypes tested, the highest ECI and ECD of the whole larval instars (12.323±0.310 and 32.357±5.508, respectively) were observed on Talaye and the lowest ones (5.947±0.257 and 6.922±0.320, respectively) were on Okapi. Together, Talaye and Okapi were the most suitable and unsuitable genotypes, respectively, for H. armigera larvae.

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