This research has considered the effect of retroactive inhibition on contextual Interference in acquisition, retention, and transfer. Three independent blocked groups, blocked without retroactive inhibition (BL-without), blocked with 18 trials of retroactive inhibition (BL-18), and blocked with 36 trials of retroactive inhibition (BL-36), were created that varied in order of presentation of tasks. By testing a single task in retention and creating three independent blocked groups, varying amounts of retroactive inhibition were produced. This isolated the effects of retroactive inhibition on blocked compared to control and random subjects' retention. Male students of Amirkabir university of Tehran were population of this investigation. Seventy-five subjects (M=26, SD=3.18) who had evaluated themselves as not experienced in sport skills were selected randomly and fifteen subjects were randomly assigned to the five groups (random, control and three block groups). Findings of this research have shown that random group in acquisition have perform so weak and it was so different and positive in retention and transfer. The results support previous contextual Interference findings and suggest that retroactive inhibition influences the retention deficits demonstrated by blocked compared to random subjects.

The relationship between Iran and the Arab countries and the divergence of these two languages from each other has led to many similarities in the bilingual language system. One of the important issues in this regard is the phenomenon of "linguistic Interference" that occurs when using the Arabic language and affects the process of teaching and learning Arabic. The linguistic Interference between these two languages has two effects: 1-Positive effect 2-Negative effect. In addition to the negative effect, Interference also has a positive effect, which can facilitate the positive aspects of Interference to facilitate the teaching and learning of the Arabic language. In this research, by extracting the similarities in phonology, words and grammar of two languages and putting them together, we want to examine the fact that the interaction between the two languages is not only negative but also positive and the learner knows These linguistic similarities can better learn some concepts (from phonology to grammar) in Arabic. Thus, have deeper and more conscious learning. The results show that many Arabic words in Persian have not undergone a semantic change and have the same meaning in both languages that this lack of semantic change will make it easier to learn some of the words involved. On the other hand, there are some grammatical similarities between the two languages, which facilitate teaching and learning by using Arabic language teachers and instructors of these similar grammatical interactions between the two languages in the teaching process. The second language learner is always looking for a way to make learning easier and more attractive to him, so by using more of these similarities and reminding the learner during the training, his desire to learn Arabic will increase.

The purpose of this research is to examine contextual Interference effect on performance of three different types of handball skills. 48 girl students from secondary school of West Islamabad had been chosen that any of them had never participated in Handball competition. All of the students have participated in pretest and then had been randomly divided into 3 equal major groups. Each major group divided once again into 2 minor groups named as Blocked and Random groups, each of which contains 8 students. Each group exercised in 8 sessions with a specialized program for the group. In experiment 1, tasks were push shot from 6, 7.5 and 9 meters distance. In experiment 2, tasks were push shot, leys hot and layup. In experiment 3, tasks were push shot, dribbling and chest pass. Results showed that differences between various methods of arrangements and performing exercise in acquisition phase were not significant. In conclusions the results of this research according to Lee & White (1990) showed that field tasks needs too much practice trials to appear the contextual Interference effect. But differences between various methods of arrangements and performing exercise in transfer phase were significant. These results support the Action plan reconstruction hypothesis (Lee & Magill, 1985).

This study was done to answer, whether regular increased of contextual Interference is more effective than blocked either random practice schedule for learning of passes in basketball. N=30 undergraduate novice boys randomly assigned in three groups. The groups differed in practice schedule of three different basketball related passes. The blocked group practiced 10 trails from each pass repeatedly. The random group executed 30 trails per session with random selection from three types of passes. In the first session, the increasing group practiced one of the passes nine blocked trials and the last pass was selected randomly. The practice schedule of this group was changed in this condition that with increasing the acquisition sessions (nine sessions), one pass was reduced from blocked passes and one pass added to random passes (10% per session). The results indicate that regular increasing vs. random practice schedule induced better performance in delay retention and transfer tests (p<0.01). In general, it was suggested that for facilitating learning of several motor skills, the practice schedule of sessions shall be started from low Interference and continue toward high Interference.

Field experiments were conducted to investigate the effect of herbicide doses on corn-multiple weed competition.Sixteen weed density combinations consisting of 4 densities of redroot pigweed × 4 densities of common cocklebur under five doses of herbicide were assessed. The two weed species responded differently to herbicide doses.Competitivity of redroot pigweed decreased with increasing herbicide dose and was completely removed by applying herbicide at 0.5 of full recommended dose, but for common cocklebur an initial increase occurred at 0.25 rate of full dosage. The relationship between weed competitivity and herbicide dose was well-described by standard dose response curve and Brain & Cousens model for redroot pigweed and common cocklebur, respectively. A combined model incorporated standard dose response curve and Brain & Cousens function into the multivariate rectangular hyperbola competition model gave a good description of corn yield. When no herbicide was applied, the competitivity of common cocklebur was approximately 1.7 times greater than that of redroot pigweed and 63% of yield loss occurred from the combination of 8 common cocklebur and 12 redroot pigweed plants m-2. Where the density of common cocklebur was low (0 to 4 plants m-2) applying herbicide at half the full recommended dose could save the yield, but with increase in common cocklebur density, the herbicide reduced doses failed to prevent the yield loss. Even at full recommended dose of herbicide, corn yield suffered loss of 6 to 10 percent from high density of common cocklebur.Nomenclature: Nicosulfuron; common cocklebur, Xanthium strumarium L.; redroot pigweed, Amaranthus retroflexus L.; corn, Zea mays L.

As nowadays the GPS navigation system has more usage in different areas, increasing its efficiency and accuracy has gained more importance. The transmitted signal travels a long distance from the satellites to reach the receivers on the ground, so its power fades. This faded signal can easily be affected by intentional noises, the so-called jamming, or unintentional noises. One of the most destructive kinds of jamming is the continuous wave (CW) jamming. The most favored method for countering this jamming is the notch filter. Therefore, in this paper, an adaptive notch filter (ANF) with a narrow response in proposed to reduce the effects of CW jamming. A kind of PSO evolutionary algorithm called the improved particle swarm optimization algorithm (IPSO) is used to adapt the filter’ s coefficients according to the power and frequency of the jamming signal. Evolutionary algorithms are used in problems without any straight forward answer, and that is why we chose this method for designing the filter. It also reduces the complexity of solving such mathematical problems. Finally, the efficiency of the proposed method is compared to other similar solutions, showing a significant improvement in the similarity of recovered signal to the original signal (up to 99%), as well as an increase in the number of observed satellites up to 6, and error reduction in determining the user coordinates which is the primary goal of the GPS system.