نشریه کارافن
سال یازدهم شماره 34 (پاییز و زمستان 1392)

Variable is an abstract concept and one of the most fundamental and important concept in algebra and understand many algebra concepts such as algebraic equation and function depend on it. Understanding the concept of variable is the base of success students in algebra. The ability of conceptual understanding and applying variables are important factors for succession of students in algebra. Although the variable concept is the foundation of most algebraic concepts, but in many classes that algebra presents, it rarely discussed. Research shows that students when are working with the variable have numerous misconception. Misconceptions, show imperfect knowledge and experience of students how is formed in the teaching-learning situation that must be identified and roots. The purpose of this research that has done in analytical- descriptive method, identifying and classifying the student`s misconceptions in applying variable, along with the reasons for the misconception and to investigate that which one of the misconceptions about the variable, is deeper. Because of the teacher`s knowledge from understanding and student`s misconceptions about the concepts, is very important for teaching. The results of this research give teachers the opportunity to make students aware of the misconceptions; they can correct them and try to develop student's understanding of the concept of variable.

Although there are a lot of research about students’ misconception and errors in doing mathematic and in spite of changes in mathematics curriculum, students continue to misunderstand and to make many errors. Maybe it could be said that algebra and especially equations and inequalities have maximum number of these misconceptions in all branches of mathematics. So in this paper we begin with different methods of teaching algebraic inequalities, identify different methods of students’ thinking about them and characterize prevailing students’ errors and misconceptions in this area. In doing this research, we find that with using different representations for algebraic inequalities and different methods for solving them teachers can create opportunity for students to reflect on their misconceptions and this will help them to decrease their errors and misconceptions.

These days, we see many mistakes in mathematical textbooks of high school from many wrong shapes and misprints to many other flaws. Unfortunately, not only these mistakes have not been corrected but also have increased because the textbooks have been written and changed quickly and carelessly. Furthermore, the authors are not familiar with students and high schools well enough. So, they bring some questions up which are puzzling for students and their teachers. Sometimes these mistakes cause bad education in other aspect of student’s lives. We want to indicate some of these mistakes in textbooks of high schools. Teachers have to spend more power to understand textbooks and author’s purposes instead of teaching. Therefore, they prefer to leave textbooks and use their notes and other books. Consequently, it increases expenses for society and family. In this decade that students can easily draw and analyze the chart of complicated functions by their mobiles, existence of error in charts of textbooks is not accepted. The authors can bring any subject up as mathematical questions in any field because the only department which analyzes textbooks is ministry of education. Should not the authors be responsible for the result of their work? Is it true that anyone who has higher education can be the author of mathematical textbooks without any experience in teaching at high schools?

In this paper, first of all, the properties of conventional fixed length tests are investigated and the flaws of this kind of tests are mentioned. Then, the adaptive tests are intoduced and after investigating their properties, the pros of adaptive tests in comparison to conventional fixed length tests are mentioned. These advantages has made adaptive tests superior to conventional fixed length tests. Two major theoris in educational mesuarement, which are classical test theory and item response theory, will be introduced along with their item difficulty and discrimination parameters. The advantages of Item Response theory in comparison to the classical test theory are mentioned to imply the need for reconsidering the fundemental theories of testing process. The pros and cons of adaptive tests in comparison to conventional fixed length tests will be mentioned along with some comments about how much the pros of adaptive tests are important and how the cons of adaptive tests can be fixed, as well. The advantages that brought by computers has made the computerized adaptive tests a powerfull tool in measuring examinee's ability levels. In fact, this paper tries to answer this main question: why one should use computerized adaptive tests instead of conventional fixed length tests?

Accountants are required to follow several codes of ethics in order to perform their duties in an independent, expert and targeted format. The main objective of the accountants is to certify the data in the financial statements. Organizational structure, incentives and ethics are strictly tied to each other. Establishing moral principles and ethical training programs in an organization will result in enhancing the quality, credit and reputation of a firm and increasing stock price. In the present environment, companies are under pressure to follow ethical codes in order to supply qualified and reliable productions to the market. Accounting and auditing companies are not exceptions and their services should be of high quality. There is a question about the degree to which the accountants follow the principles of accounting ethics. According to this study, economics deals with three main principles of traditional ethical topics. Different types of ethics and ethical development model of Kolberg are developed in this study. Finally, the ethical scandals in accounting are presented. It is further discussed whether accounting or commerce is responsible of the scandals.

The purpose of this study was effects of eccentric exercise on athlete and non-athlete boys. 12 athlete and non-athlete boys are selected to cluster sampling with age (17/58±0/51,17/42±0/51), height (1/74±0/05,1/79±0/1cm), weight means (65/08±4/32,71/17±3/88 kg), respectively. Each of subjects performed per 50 eccentric contractions with 85 percent of concentric strength maximal at 5 set for 10 repeats on nondominate arm. Each of set included 10 contractions. The between each of set is rested 1 minute. To evaluate CKMM enzyme on 3 times performed blood sampling at pre-test, 0/5 and 24 hours post-test. Repeated-measure ANOVA was used as statistical method (p≤0.05). The levels of athlete and non-athlete CKMM were different significantly at 0/5 hours. CKMM levels were increased in athlete than non-athlete. Different minimal was on 24 hours post-test. CKMM levels at 0/5 and 24 hours post-test was large than CKMM level at pre-test and 24 hours than to 0/5 hours in athlete and non-athlete. Findings suggest that CKMM levels following eccentric strength contraction is increased at 0/5 hours in athlete and at 24 hours in non-athlete.