Background and Objectives: Leaf Area Index (LAI) is one of the most important structural parameters in agricultural, range and forest ecosystems and variation of energy, water, and gases are tightly coupled to LAI. According to the novelty of LAI research in Iran, this study aimed to evaluate different direct ground-based methods for determining LAI. Material and Methodology: This research has been done by literature reviews by using internet databases. There are two main categories of procedures to measure LAI: ground-based and remote sensing methods, and ground-based methods divided into direct and indirect (estimation) methods. Findings: Although, in the past two decades, the tendency to use indirect ground-based as well as remote sensing methods for estimating g LAI has increased, but for reasons such as needing semi-sophisticated and sophisticated instruments and lack of free access to satellite images in the greater part of the world, caused the direct ground-based methods for calculating LAI has been widely used. Moreover, the high precision and accuracy of direct ground-based methods compared to direct ground-based and remote sensing methods is another reason for preferring direct ground-based methods. Discussion and Conclusion: The results of this study showed that the Litter Trap method could be the most efficient method for measuring LAI, and we proposed this method in future research, concerning very less destruction to nature as well as high accuracy and precision.

example of a fully relativistic equation with both negative and positive energy solutions. The effect of the negative energy states was mitigated by maximizing the energy with respect to a relevant parameter while at the same time minimizing it with respect to another parameter in the wave function. The Cornell potential and a power-law scalar and vector potentials were used in our calculations for the quark confinement. Cares were taken to avoid the Klein paradox by the dominance of the scalar component over the vector part.

Infiltration in the soil is one of the determining parameters in irrigation, which affects all factors related to irrigation evaluation. On the other hand, spatial and temporal variability of infiltration parameters are a major physical limitation in managing and achieving high application efficiency of surface irrigation. The objective of the present study is to evaluate scaling method in estimating the infiltration equation parameters in furrow irrigation based on Elliott-Walker, Shepard et al., Ebrahimian et al., infilt, Valiants and Milapali methods, and also to evaluation the accuracy of the middle point and end point for the scale process. For this purpose, a reference infiltration curve is considered and then using the time of to reach the middle and end of the furrow, the scale factor of that furrow is obtained. In this research, the measured data for six furrows with soil texture and different input data were considered. According to the results, if the furrow end point is used to calculate the scaling factor in the Scaling method, the accuracy of this method will be significantly increased .Based on the evaluation, Ebrahimian's method had the best results. In the infilt method, there is no noticeable difference between using the middle point and the end point. In many cases, using the middle point in order to obtain the parameters of the penetration equation overestimates the advance value. The simplicity of the one-point scaling method is one of the advantages of this method in comparison with other methods of obtaining penetration parameters

In this paper, we propose the numerical solution for a fuzzy nonlinear equation by fixed point method (simple iteration method). The fuzzy quantities are presented in parametric form. Some numerical illustrations are given to show the efficiency of method.

The current study was carried to find distribution pattern of Zygophyllum eurypterum Ephedra strobilceae , Haloxylon aphyllum and Cornulaca monocantha in Poshtkouh rangelands in Yazd province using distance and quadrat indices. To do this, in a 20 ha area, 4 transects with a length of 400 m were established based on random-systematic method. Vegetation sampling was performed along each of transects .in 30 points. In each point, its distance to nearest plant, distance between mentioned plant and its nearest neighbor, and distance between the point and second plant was measured. Using these measurements, distance indices including; Eberhart, Hopkins and Holgate were calculated. To use quadrat indices, in each of abovementioned 30 points, quadrats with different sizes (according to plant kinds) were established and number of plants within quadrats were counted. Regarding obtained data from quadrats, indices of variance/mean, Morisita and standard Morisita indices were calculated. Results showed that Z. eurypterum, H aphyllum and C. monocantha distribution pattern was random, while E. strobilceae distribution pattern follows a clumped pattern. Also, it was cleared that the accuracy of distance methods was higher than quadrat methods and resulted to more reliable results in determination of plants distribution pattern.

In this research, the coverage of Amygdalus eburnea and Calligonum comosum was evaluated by three methods: quadrat, visual estimation in quadrat and line-interception on rangelands of Shahr-e babak (Kerman province) in summer season of 2009. The goal was determination of the accuracy and effectiveness (speed of sampling) of these methods. The methods were compared by t-test. Coverage estimation of A. eburnea with quadrat and line-interception methods (except for the habitat with moderate density) showed no significant difference to control method, but visual estimation in quadrat method showed significant difference with control method in three habitats. Also, coverage estimation of C. comosum with quadrat method, visual estimation in quadrat method (except of moderate density habitat) and line-interception method (except for the habitat with high density) showed no significant difference to control method. In the case of A. eburnean, the highest and lowest accuracy were recorded for quadrat method and line-interception method in all three habitats, respectively. In the case of C. comosum, line-interception method and visual estimation method had the highest and lowest degree of accuracy in all three habitats, respectively. Therefore, quadrat method and line-interception method are suggested for coverage estimation of A. eburnean and C. comosum, respectively.

Let C be a nonempty closed convex subset of a real Hilbert space H. Let {Sn} and {Tn} be sequences of nonexpansive self-mappings of C, where one of them is a strongly nonexpansive sequence. K. Aoyama and Y. Kimura introduced the iteration process xn+1=bnxn+(1-bn) Sn (anu+(1-an) Tnxn) for finding the common fixed point of {Sn} and {Tn}, where uÎC is an arbitrarily (but fixed) element in C, x0ÎC arbitrarily, {an} and {bn} are sequences in [0; 1]. But in the case where uÏC, the iterative scheme above becomes invalid because xn may not belong to C. To overcome this weakness, a new iterative scheme based on the thought of boundary point method is proposed and the strong convergence theorem is proved. As a special case, we can find the minimum-norm common fixed point of {Sn} and {Tn} whether 0ÎC or 0ÏC.