排序方式： 共有86条查询结果，搜索用时 15 毫秒
21.
M. Mardaneh Khatooni B. Mojazi Amiri A. Mirvaghefi V. Jafari S. H. Hoseinifar 《Aquaculture International》2012,20(6):1097-1105
Persian sturgeon eggs were fertilized with different levels of salinities (0.5, 2, 4, 6, 8, 10, 12?ppt), and then each group was incubated in the same salinity until hatch. The fertility (%), hatching rate as well as larvae cumulative mortality rate and abnormality (%) were measured. Our Results revealed that Persian surgeon eggs could be fertilized in the different salinity concentrations but not more than 4?ppt. Moreover, hatching rate decreased with increase in salinities more than 2 and 4?ppt, respectively, and no larvae hatched in 6?ppt salinity. According to these results, the salinity tolerance threshold for Persian sturgeon larvae hatching in brackish water is less than 4?ppt. 相似文献
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23.
Ebrahim Amiri 《Communications in Soil Science and Plant Analysis》2016,47(3):387-403
The objective of this study was to adapt and test the ability of the AquaCrop model under different nitrogen and irrigation management conditions in northern Iran. A three-year field experiment was conducted at the experimental farm of the Iranian Rice Research Institute in Rasht, Iran, from 2005 to 2007. Irrigation treatments comprised continuous submergence, irrigation at 5-day intervals, and irrigation at 8-day intervals. Nitrogen (N) application levels were 0, 45, 60, and 75 kg N ha?1. The goodness of fit between observed and simulated canopy cover, total and panicle biomass, grain yield, and final biomass was assessed by means of the coefficient of determination (R2) and the absolute and normalized root mean square errors (RMSEn). Results of the statistical test of the model for total and panicle biomass showed moderately high R2 (≥0.90) and moderate RMSEn (6–36%) values, confirming that the model simulated the total and panicle biomass accurately. The model was simulated for CC with RMSEn and R2 of 28 and 0.82, respectively. The agreement between predicted and observed rice grain yield and final biomass were with R2 of 0.81 and 0.82 and RMSEn of 13 and 10% respectively. 相似文献
24.
Azadeh Safadoust Elham Amiri Khaboushan Ali Akbar Mahboubi Bahram Gharabaghi Mohammad Reza Mosaddeghi Beau Ahrens 《Archives of Agronomy and Soil Science》2016,62(5):674-687
This study was conducted to investigate the effects of soil structure on bromide (Br) transport through three soils with granular, prismatic, and single-grain structures. The breakthrough curve (BTC) of the single-grain structure was sigmoidal, symmetrical and similar to a piston flow, showing the dominance of mass flow. In contrast, the BTCs of the granular and prismatic structures were initially steep, becoming more gradual at high pore volumes (PVs). The stable structure and preferential pathways caused the early breakthrough of Br in the leachate of these columns. The convection–dispersion equation (CDE), mobile–immobile water (MIM), and dual-permeability (DP) models were fitted to observed data using the program HYDRUS-1D. The equilibrium transport model (CDE) was not as successful as non-equilibrium (MIM and DP) models in describing the Br transport in prismatic and granular soil columns, although it was able to describe the Br transport in single-grain column well. Overall, the results demonstrated the importance of soil structure in pollutant transport through soils. 相似文献
25.
One goal in the face of drought stress conditions is to increase growth and yield through the reduction of negative effects of stress. Vermicompost can play an effective role in plant growth and development and in reducing harmful effects of various environmental stresses on plants due to its porous structure, high water storage capacity, having hormone-like substances, plant growth regulators, and high levels of macro and micro nutrients. This study considered the physiological, biochemical, and photosynthetic responses of the chickpea to different combinations of vermicompost and water stress in a greenhouse environment. Two factors were involved, addition of vermicompost to soil at four ratios: control (100 wt% (weight percentage) soil); 10 wt% vermicompost+90% soil; 20 wt% vermicompost+80 wt% soil; 30 wt% vermicompost+70 wt% soil weight percentage, and treatment of water stress at three levels including 75, 50, and 25% of field capacity. The results showed that vermicompost had a significant effect on all traits under stress and non-stress conditions. Application of vermicompost in soil, especially at the levels of 20 and 30 wt% significantly increased all studied traits under non-stress conditions. Under moderate stress conditions, vermicompost at 30 wt% treatment resulted in a significant increase in the photosynthetic pigments, CO2 assimilation rate, internal leaf CO2 concentration, transpiration, the maximal quantum yield of photosystem II (PSII) photochemistry (Fv/Fm), concentrations of Ca and K in root and leaf tissues, proline and soluble protein contents in root tissues. Peroxidase (POX) and catalase (CAT) enzyme activities decreased significantly with increasing proportions of vermicompost, but the activity of superoxide dismutase was not significantly different. In conclusion, the above results showed that vermicompost fertilizer had a positive effect on physiological, biochemical, and photosynthetic responses of chickpea under non-stress and moderate stress conditions, but no positive effect was determined under severe water stress. 相似文献
26.
Lamia Vojodi Mehrabani Rana Valizadeh Kamran Mohammad Bagher Hassanpouraghdam 《Communications in Soil Science and Plant Analysis》2017,48(16):1860-1867
Lavandula stoechas L. plant is a perennial evergreen used as a fragrant ornamental and medicinal plant. In order to study the effect of foliar spray of zinc sulfate (ZnSO4) (0, 1000, and 2000 mgL?1) and sodium chloride (NaCl) salinity (0, 75, and 150 mM) on some physiological characteristics of Lavandula stoechas L. plants, a pot experiment was carried out at the Research Greenhouse of Azarbaijan Shahid Madani University, Iran. Physiological characteristics [root and leaf dry weights, total soluble solids (TSSs), total anthocyanins, chlorophyll b, Zn2+, potassium (K+) contents, and K+/Na+ ratio] were significantly affected by the interaction effects of ZnSO4 foliar application and salinity levels. The highest root dry weight, chlorophyll b, anthocyanin, and Zn contents as well as TSS were found in the plants with NaCl0 × ZnSO4 2000 mgL?1. For Na+, the greatest value was recorded with NaCl 150 × ZnSO40. The highest K+/Na+ ratio was found in the control plants. Foliar application of ZnSO4 promoted the total phenolic content, especially at 2000 mgL–1. The highest amounts of flower dry weights were recorded at NaCl0. Chlorophyll a, total flavonoids, stem dry weight, and essential oil content were affected with ZnSO4 treatment and salinity levels. The highest values for the essential oil content, chlorophyll a content, and stem dry weight were attained by the nonsaline treatment. Both foliar application levels positively influenced the essential oil and flavonoid contents of the plants. The results reveal that zinc application had marked effects on the physiological characteristics of Lavandula stoechas L. plants growing under salinity stress conditions. 相似文献
27.
Mohammad Javad Amiri Ali Shabani 《Communications in Soil Science and Plant Analysis》2017,48(14):1669-1683
Leaf Area (LA) is a key index of plant productivity and growth. A multiple linear regression technique is commonly applied to estimate LA as a non-destructive and quick method, but this technique is limited under the realistic situation. Thus, it is indispensable to elaborate new models for estimation. In this research, the performance of the Adaptive Neural-Based Fuzzy Inference System (ANFIS) in predicting the LA of 61 plant species (C) was investigated. Four parameters including leaf length (L), leaf width (W), C, and specific coefficient (K) for each plant were selected as input data to the ANFIS model and the LA as the output. Seven different ANFIS models including different combinations of input data were constructed to reveal the sensitivity analysis of the models. The normalized root mean square error (NRMSE), mean residual error (MRE), and linear regression were applied between observed LA and estimated LA by the models. The results indicated that ANFIS4-K2min which employed all input data was the most accurate (NRMSE = 0.046 and R2 = 0.997) and ANFIS1 which employed only the K input was the worst (NRMSE = 0.452 and R2 = 0.778). In ranking, ANFIS4-K2ave, ANFIS4-K1min, ANFIS4-K1ave, ANFIS3, and ANFIS2 ranked second, third, fourth, fifth, and sixth, respectively. The sensitivity analysis indicated that the predicted LA is more sensitive to the K, followed by L, W, and C. The results displayed that estimations are slightly overestimated. This study demonstrated that the ANFIS model could be accurate and faster alternative to the available laborious and time-consuming methods for LA prediction. 相似文献
28.
Soroush Sardari Motahareh Amiri Hourieh Rahimi Mohammad Kamalinejad Jamshid Narenjkar Mohammad Sayyah 《Iranian Biomedical Journal》2015,19(1):45-50
Background:
Cicer arietinum (Chickpea) is one of the most important harvests in the world with high nutritional value. Lack of essential oils in the seeds of Chickpea is an advantage in search for drug-like molecules with less toxicity. We evaluated anticonvulsant effect of C. arietinum in common animal models of epilepsy. Methods: Dichloromethane extract was obtained from C. arietinum seeds by percolation. Acute toxicity of the extract was assessed in mice. Protective effect of the extract was examined against tonic seizures induced by maximal electroshock (MES; 50 mA, 50 Hz, 1 s) in mice, clonic seizures induced by pentylenetetrazole (PTZ; 60 mg/kg, i.p.) in mice, and electrical kindling model of complex partial seizures in rats. The extract was fractionated by n-hexane to f1 and f2 fractions. The extract and fractions underwent phytochemical analysis by thin layer chromatography. The active anticonvulsant fraction, f1, was subjected to matrix assisted laser desorption/ionization (MALDI) mass analysis. Results: The crude extract had neither toxicity up to 7 g/kg nor protective activity in MES and kindling models. However, it significantly inhibited clonic seizures induced by PTZ. f1 fraction mimicked protective effect of the extract. Phytochemical screening revealed the presence of considerable amount of alkaloids in the extract and fractions. Moreover, a novel structural class was detected in f1 fraction. Conclusion: Finding an anticonvulsant molecule pertaining to a new structural class in the seeds of C. arietinum promises an effective and inexpensive source of antiepileptic medication. Further studies are needed to identify its mechanism of action and more clues into its structure-activity relationship. Key Words: Anticonvulsants, Cicer, Kindling, Pentylenetetrazole (PTZ) 相似文献
29.
Amiri Z Mohammad K Mahmoudi M Zeraati H Fotouhi A 《Pakistan journal of biological sciences: PJBS》2008,11(8):1076-1084
This study is designed to assess the application of neural networks in comparison to the Kaplan-Meier and Cox proportional hazards model in the survival analysis. Three hundred thirty gastric cancer patients admitted to and surgically treated were assessed and their post-surgical survival was determined. The observed baseline survival was determined with the three methods of Kaplan-Meier product limit estimator, Cox and the neural network and results were compared. Then the binary independent variables were entered into the model. Data were randomly divided into two groups of 165 each to test the models and assess the reproducibility. The Chi-square test and the multiple logistic model were used to ensure the groups were similar and the data was divided randomly. To compare subgroups, we used the log-rank test. In the next step, the probability of survival in different periods was computed based on the training group data using the Cox proportional hazards and a neural network and estimating Cox coefficient values and neural network weights (with 3 nodes in hidden layer). Results were used for predictions in the test group data and these predictions were compared using the Kaplan-Meier product limit estimator as the gold standard. Friedman and Kruskal-Wallis tests were used for comparisons as well. All statistical analyses were performed using SPSS version 11.5, Matlab version 7.2, Statistica version 6.0 and S_PLUS 2000. The significance level was considered 5% (alpha = 0.05). The three methods used showed no significance difference in base survival probabilities. Overall, there was no significant difference among the survival probabilities or the trend of changes in survival probabilities calculated with the three methods, but the 4 year (48th month) and 4.5 year (54th month) survival rates were significantly different with Cox compared to standard and estimated probabilities in the neural network (p < 0.05). Kaplan-Meier and Cox showed almost similar results for the baseline survival probabilities, but results with the neural network were different: higher probabilities up to the 4th year, then comparable with the other two methods. Estimates from Cox proportional hazards and the neural network with three nodes in hidden layer were compared with the estimate from the Kaplan-Meier estimator as the gold standard. Neither comparison showed statistically significant differences. The standard error ratio of the two estimate groups by Cox and the neural network to Kaplan-Meier were no significant differences, it indicated that the neural network was more accurate. Although we do not suggest neural network methods to estimate the baseline survival probability, it seems these models is more accurately estimated as compared with the Cox proportional hazards, especially with today's advanced computer sciences that allow complex calculations. These methods are preferable because they lack the limitations of conventional models and obviate the need for unnecessary assumptions including those related to the proportionality of hazards and linearity. 相似文献
30.
Ahmad Noori Bagher Mojazi Amiri Alireza Mirvaghefi Daniel W. Baker 《Aquaculture Research》2010,41(6):871-877
To induce synchronized ovulation, migrating wild Caspian brown trout (Salmo trutta caspius) females were treated with two interperitoneal injections of Des‐Gly10, d ‐Ala6 LHRH (LHRHa), given 3 days apart. Two injections of 100 μg kg?1 body weight of this hormone effectively induced ovulation. Within 27 days from the second injection, all fish injected with 100 μg kg?1 LHRHa had ovulated compared with 54.5% of the controls. The mean time to ovulation was reduced significantly (P<0.05) from 31.67±4.84 days in control fish and 28.83±7.31 days in sham‐treated fish to 16.36±1.61 days in fish injected with 100 μg kg?1 LHRHa. The fertilization rate in 50 and 100 μg kg?1 LHRHa‐injected fish was significantly lower than that in the control fish (P<0.05). In fish injected with 50 and 100 μg kg?1 LHRHa, significant (P<0.05) changes in testosterone (T) and 17α‐hydroxyprogestrone (OHP) levels were observed. After the second LHRHa injection, the fish injected with 100 μg kg?1 showed the highest serum levels of testosterone and OHP. These results demonstrate that the use of LHRHa can effectively reduce the mean time to ovulation and induce synchronized ovulation in Caspian brown trout. 相似文献