In the pastures, floods often happen due to surface runoff and violent storm. Initial soil water content has a direct influence on the infiltration capacity and as result on surface runoff. Hydrological models are strong instruments to investigate the main physical processes involved in the watershed. In the present study regression models, obtained from relationship between independent and dependent effective variables on runoff production. Through modeling used in this study, the daily precipitation and water discharge data for the period from 1974 to 2000 collected, refined and analyzed.Subsequently the pertinent models were recognized with using the concept of dynamic modeling statistical software's Excel 2003 & SPSS 11.5. The analysis of results showed that the effective time of antecedent precipitation and the most effective daily precipitation on daily discharge. The results indicated that the antecedent and daily precipitation were affected on the daily discharge of Tangrah pasture watershed in duration of different months significantly. It was also found out that the daily discharge was affected by the precipitation occurred respectively before three days while this is contrary to emphasizes of other common methods of estimate of runoff that was based on effect of precipitation of fifth previous days on daily discharge due to specific governing conditions on study watershed. The present study emphasizes determination of exact quantity of effective antecedent precipitation in different places attention to effective spatial & temporal changes on output discharge of watershed.

Splash erosion is one of the most important kinds of water erosion. Splash of soil particles may affected by some factors especially antecedent rainfall event. Up to now, there isn’ t any study on the effects of antecedent rainfall on splash erosion in the next rainfall. This study was conducted to investigate the effect of antecedent rainfall on the particles splash in a marl soil. Toward this, aggregates with a diameter of 6-8mm were taken from a marl soils under fallow condition in 2016. Aggregates were packed in 24 boxes with 30cm× 40cm dimensions and 30cm depth to investigate effect of eight rainfall durations levels at three replications. Simulated rainfall was applied to soil samples with eight durations (0, 7, 14, 21, 28, 35, 42 and 49 min). Aggregate breakdown and soil water content were determined in the soil samples after one day. After one day, soil boxes were placed under the same rainfall with a constant intensity of 40 mm h-1 for 15 min. Based on results, duration of antecedent rainfall significantly affected the aggregate breakdown and increased the soil water content. The longest rainfall duration (49 min) appeared the highest aggregate breakdown (21. 72%) as well as soil moisture content (29. 08%). The amount of splash erosion in the next rain event was significantly influenced by the changes in two soil variables, i. e. aggregate breakdown (P <0. 05) and soil water content (P <0. 01), implied by the antecedent rainfall. Multiple linear regression analysis showed that among the two soil variables, antecedent soil water content is the most important factor determining the splash erosion variation in the next rain event (R2 = 0. 83, P<0. 01). The splash erosion in each rain event could be reliably estimated by determining the antecedent soil water content.

Runoff is one of the important parameters in hydrologic cycle and water resources management of basins. In this research, Remote Sensing (RS) and Geographic Information System (GIS) techniques were used for runoff potential estimation in Khosro-Abad watershed, located in the Hamedan region. In this regard, first, the various thematic maps layers such as Digital Elevation Model (DEM), land use and land cover, slope, soil hydrologic groups and sub-basins location were prepared. Then, based on the prepared thematic layers, a weighting method was developed to runoff potential estimation of the area. To spatial runoff variability investigating, the classifieds estimated runoff potential (low, medium, high and extreme classes) was evaluated using the SCS method. The SCS method was estimated based on three previous soil moisture conditions (dry, normal and wet). The results showed that the weighting method is enable to runoff potential estimation. This method can be proposed for runoff potential estimation especially in the cases that the needed data were missed. The results also showed that with the previous soil moisture increasing (from dry to wet conditions), the CN increase about 30%.

Environmental factors including rainfall are the factors affecting palatability of plants and consequently the preference value for animals. In this study, the preference value of plants was determined in Sarakhs (winter rangeland at North-East of Khorassan province) by timing method during 2007 to 2010 for the two first months of growing season (March and April). The results showed that Artemisia diffiusa, Carex physioides and Poa bulbosa were grazed in all four years by livestock, indicating that these species were more palatable. The preference value of the species differed between drought and normal years. According to the obtained results, a high correlation was found between the grazing time of Poa bulbosa and pervious rainfalls. Also, a significant relationship was found between the grazing time of Carex physioides in March and the rainfall of autumn, January and total rainfall of February and March. A significant correlation was also found between the grazing time of Artemisia diffusa in March, and the rainfall of January, total rainfall of autumn and December, and total rainfall of autumn, January, and February. This research was aimed to determine the seasonal and annual forage preference value with regard to the rainfall fluctuations in Sarakhs rangelands.

Undoubtedly, A Priori needs to be clarified if we are to understand the heart of Critique of Pure Reason; and Kant, precisely for this very reason, devoted a considerable part of Critique to explaining the epistemic status of A Priori, searching its origin, specifying its validity scope, and illustrating its instances. Although he, more or less, in both editions of Critique, put forward some characteristics intrinsic to A Priori (such as necessary, strictly universal, pure, clear, certain and independent of experience) since they have been also used in (pre)post-Kantian traditions, especially in a meaning different from what Kant meant, so they may simply bring about some confusions cause failing to appropriately grasp the heart of Critique. With reference to such confusions the authors make an attempt to shed light on this point in part (1). Then, in part (2-1), based on the text of Critique and its commentators’ views, authors proceed to show that to evade such confusions one should re-define necessary to “ what is emerged from the nature of the human mind” , strictly universal to “ applicable just in the realm of phenomenon” , pure to “ merely focused on the contribution of mind itself in collaboration with the objects themselves to form empirical knowledge” , clear to “ what the scope of searching for is limited to within ourselves not outside of it” and certain to “ what its scope is immutable – either regarding to its instances themselves or to their numbers” . In part (2-2), by scrutinizing the other characteristic (i. e. independent of experience), we shall show that this characteristic, besides of referring to mere structure, can refer to some kind of knowledge on which every possible experience is based; moreover, we shall determine the relation of above characteristic to pre(post)-Kantian traditions.

The issue of God's foreknowledge and its relation with Human being's freewill is one of the main subjects that from the beginning have been controversial among Christian and Judaic theologians and philosophers. So in Islamic and western world have proponed many solutions for solving this problem.In this article our purpose is taking into consideration some of these solutions that each of which has strong and weak points. At the end, we will defend of the solution that, in comparison with others, is more reliable and sufficient.