The main objective of this study is to determine the predictive power of mathematics selfefficacy resources and perception of science self-efficacy on academic achievement. The study, adopting a relational screening model, was conducted with a total of 698 students in sixth, seventh and eighth grade level of a state secondary school. Mathematics self-efficacy resources and science self-efficacy scales were used as data collection tools. Additionally, the half-terms report card grade point averages prior to the term when the study was conducted were also taken into account to determine students' academic achievements. Data analysis was performed by Pearson productmoment correlation technique and multiple linear regression analysis. According to the obtained results, resources of mathematics self-efficacy and perception of science self-efficacy were found to be significantly correlated with academic achievement in high, medium and low levels of influence. Belief in learning ability, belief in skills, mastery experiences, social persuasions and physiological states, which have significant impacts on the academic achievement, account for 48 % of the variance in the academic achievement. Indirect experiences, however, do not have a significant effect on academic achievement. Besides this, when examined the relationship between dimensions of science self-efficacy perception and mathematics self-efficacy resources; a significant relationship was observed between the belief in learning ability and mastery experiences, indirect experiences and physiological states, belief in skills and mastery experiences, indirect experiences and social persuasions.

Bu araştırmada yedinci sınıf öğrencilerinin, (i) cinsiyete göre cebirsel düşünme düzeylerini, (ii) cebir öğrenme alanındaki pozitif ve negatif beceri eksikliklerini incelemek amaçlanmıştır. Tarama modelinin benimsendiği çalışma, yedinci sınıf düzeyinde toplam 185 öğrenci ile yürütülmüştür. Veri toplama aracı olarak; literatürde yer alan çalışmalar, ortaokul matematik ders kitapları ile öğretim programında yer verilen ilgili kazanımlar göz önüne alınarak hazırlanan 10 soruluk "Cebirsel Düşünme Düzeyi Belirleme Aracı (CDDBA)" kullanılmıştır. Verilerin analizinde betimsel istatistiksel tekniklerinden yararlanılmıştır. Betimsel analiz sonuçlarına göre, öğrencilerin cebir öğrenme alanı ile ilgili doğru cevap oranlarının ilk aşamadan son aşamaya gidildikçe belirgin şekilde azaldığı belirlenmiştir. Öğrencilerin pozitif beceri eksiklikleri iki aşamada %27, üç aşamada %13 iken negatif beceri eksiklikleri iki aşamada %49, üç aşamada %19 olarak bulunmuştur. Diğer yandan öğrencilerin cebirsel düşünme düzeylerinin genel ortalaması 15.09, her bir soruya göre erkek öğrencilerin ortalaması 1.32, kız öğrencilerin 1.70 olarak hesaplanmıştır. Öğrencilerin cebirde yaşadıkları güçlüklerin temel nedenlerini belirlemeye yönelik öğretim programı dâhilinde boylamsal çalışmalara ağırlık verilmesi öneri olarak sunulmuştur.

The basic aim of the study was to determine the power of mathematics and science self-efficacy resources as the predictors of academic success. The relational scanning model was used in the study, and the study was conducted with 492 students who were studying at sixth and seventh grades of a state school. The mathematics and science self-efficacy resources scales were used as the data collection tool. In addition, the school reports of the semester before the study was conducted were used to determine the academic success levels of the students. The Pearson moments multiplication correlation technique and multiple linear regression analysis were used in the analysis of the data. According to the results, there were significant relations between the mathematics and science selfefficacy resources and the academic success levels at high, medium and low levels. The personal experiences, indirect experiences and social persuasions, which have significant effects on academic success both for mathematics and for science, explained nearly 60% of the change in academic success. The physiological situations towards mathematics did not have any significant effects on academic success. According to the findings, some recommendations have also been made in the study.

In this study, the purpose were to i) determine the level of the basic psychological needs of middle school students in mathematics, and ii) examine the autonomy, attachment, and sufficiency needs of the students by considering grade levels and genders of the students. The study was conducted with 484 students (235 girls and 249 boys) studying at a public school in Izmir. In order to determine the basic psychological needs of the students in mathematics, Basic Psychological Need Scale was used. The end-term mathematical class grades were used to determine the mathematical success levels of the students. Descriptive statistical analyses, MANOVA and Bonferroni tests were made use of in the analyses of the data. According to the descriptive analyses results, the needs of the students for autonomy, attachment and sufficiency in mathematics classes were determined to be over medium level. While the highest mean value of the students in mathematics was in attachment dimension, the lowest mean value was determined in sufficiency dimension. According to MANOVA and Bonferroni test results, it was understood that the autonomy, attachment and sufficiency needs of the students with high mathematics success levels were higher than those with medium and low-level mathematical success. On the other hand, the autonomy, attachment and sufficiency need points of the sixth graders were found to be higher than those of seventh graders. It was determined that the basic psychological needs of the students did not differ at a significant level according to gender variable. As a conclusion, it is recommended that students are guided in mathematics classes for classroom activities that are proper for their abilities, interests and developments to cover their basic needs in mathematics, and feasible targets are set.

Polisiklik aromatik hidrokarbonlar organik bileşiklerin tam yanmaması sonucu ortaya çıkan toksik, mutajenik ve kanserojenik etkiye sahip organik yapıda bileşiklerdir. Endüstriyel atıklar, tarım ilaçları, çöpler, sigara dumanı ve sanayi baca gazları gibi zararlı maddelerden çevreye yayılan kimyasallar hava, su, toprak ve gıdalara karıştıklarından dolayı insan sağlığını tehdit eden önemli çevresel kirleticilerdendir. İnsanlar kirli havayı soluyarak ya da kirlenmiş su veya gıdayı tüketerek toksik ve kanserojen maddelere maruz kalırlar. Bu derlemede PAH' ların oluşum mekanizması, gıdalarda bulunuşu ve tespit yöntemleri ele alınmıştır. Anahtar Kelimeler -benzo(a)piren, gıda, HPLC-UV, PAH