In this paper, a methodology is proposed for identifying the best equations for estimating the time of concentration (ToC) of watersheds located in a specific geographic region. The methodology primarily works on the basis of modifying available equations to minimize their bias for any particular region of interest. In the methodology, for each watershed, the ToC considered as "reference" is determined using the Natural Resource Conservation Service (NRCS) velocity method employed in the TR-55 model and geographic information systems data. Moreover, a ranking-based selection strategy is developed for evaluating and selecting the best performing methods. In a case study, the proposed methodology is applied to 72 watersheds and subwatersheds in Khorasan Razavi province, Iran. According to the study, the California equation (with a correction factor of 1.715), the Kirpich (Tennessee) equation (with a correction factor of 1.721), and the Arizona DOT equation (with a correction factor of 1.126) have the best performance for the selected watersheds.

The relationship between farmers' age and these two variables should not be considered either positively or negatively for predicting farmers' attitudes on safety issues of pesticide use without taking into account other mediating variables that can also affect farmers' behavior. Differences in the perceived importance and competence of farmers on the safety measures revealed considerably different needs of farmers for future training as a result of differences in age along with other background characteristics.

No abstract

In the world of competition, manufacturing and service companies are trying to enhance their competitive capabilities in order to be able to give more value to their customers and gain prominent positions in competition with other companies. Every company tries to concentrate on its one or more capabilities in competition in order to turn them into a clear competitive advantage that improves the firm performance. In fact, it is necessary for the firms being active in market and being consistent with competitive requirements to gain and maintain a competitive advantage. This study investigates the effect of competitive capability on firm performance under environmental uncertainty conditions. The findings show that competitive capability has direct positive effect on customer satisfaction, financial performance, and market performance. In other words, enhancing these capabilities leads to improving customer satisfaction and increases market and financial performance. Investigation of the effects of different aspects of competitive capabilities on different performance aspects show that the capability of cost leadership positively affects financial performance and market performance but, has no effect on customer satisfaction. Also, the capability of differentiation has direct positive effect on customer satisfaction but affects financial performance and market performance negatively. Additionally, the examination of the moderating effect of perceived environmental uncertainty on the relationship between competitive capability and firm performance shows that in different environmental conditions, the effects of cost leadership capability on customer satisfaction, differentiation capability on financial performance, and differentiation capability on market performance are moderated. On the other word, managerial decisions in these areas are affected by environmental conditions involved in processes of material supply, production, and market demand.