Determination of pre-service elementary science teachers’ knowledge level about ozone layer

AbstractOne of the global environmental problems which threaten the earth and humanity is the Ozone Layer Depletion and the negative results that it causes. With this study, the aim is to determinate the knowledge level of pre-service elementary science teachers about the causes of the Ozone Layer Depletion, results and the precautions they will take. In this study, 30-item-questionaire has been applied to 319 pre-service elementary science teachers using survey model. Percentage (%), frequency (f) and the singlefactor variance analysis have been applied to the data obtained from application using this SPSS statistical packet program. At the end of the analysis, it has been revealed that pre-service teachers who educate the generations that will face up with this important environmental problem have both some misconceptions and inadequate and locking knowledge about Ozone Layer Depletion. Besides, it has been determinate that specific there is no difference between knowledge level of pre-service elementary science teachers about Ozone Layer according to grade level. © 2011 Published by Elsevier Ltd

Evaluation of Critical Thinking Skills and Self-Efficacy Levels among Science Teacher Candidates

The aim of this study was to evaluate and determine the critical thinking skills and the general self-efficacy of science teacher candidates. The study was performed with the participation of 32 teacher candidates from the science teaching department of a university in Turkey. Scales administered during the study included the California Critical Thinking Scale and the General Self-Efficacy Scale. Frequency distributions were calculated for data obtained from both scales. Based on the study results, it was determined that while the teacher candidates generally provided responses that illustrated effective critical thinking skills and self-efficacy, the frequency of the responses for some of the scale items lacked a clear distribution in terms of illustrating the teacher candidates’ stance towards these abilities. Keywords: Critical thinking, Self-efficacy, Science teaching, Teacher candidat

Determining the Level of Knowledge and Mental Models of Secondary School Students Regarding the Solar System

The aim of this study was to determine the level of knowledge and mental models of secondary school students regarding the solar system. The study was performed with 65 eighth grade students attending a secondary school in a provincial center in northern Turkey. In this study, students were asked to draw the solar system, and to write the names of the planets in the proper order. Descriptive analysis was performed on the drawings and written descriptions provided by the students, with the data being evaluated based on five different levels previously used by Bartoszeck et al. (2008) and Uzunkayak (2009a; 2009b). Based on the study results, it was determined that the students lacked sufficient knowledge regarding the solar system, and that they possessed erroneous information regarding the order and sizes of the planets. In addition, none of the students were able to write down the eight planets of the solar system, which further illustrated their lack of knowledge on this subject. Keywords: Solar System, Secondary School Student, Mental Model, Knowlede, Science Educatio

Teaching the Inorganic Compounds with the Application of 2-d Code

The applications of 2-d code which can be applied as an alternative tool on naming the inorganic compounds which is one of the chemical subjects that the science students have difficulty to understand, and on writing the chemical formulas can be used to raise the students’ motivation against the learning. 2-d code; has started to be popular with its properties such as its practical usage and quick working (Polat, 2014) and its application fields in the education are assessed within the scope of methods which are known as the mobile learning in the much more general meaning. In this sense, it is considered that it will facilitate the passing between the educational material through the mobile device with the printed learning material with the use of the 2-d code applications by the students. It was aimed to determine the effect of worksheets with the applications of 2-d code in teaching the inorganic compounds as one of the important subjects of chemistry to the science students with this research. The quasi-experimental design of pre and post-tests for the single group was used in the research. The study group consists of 47 science students in total who receive their training at 1st grade of Science Teaching in Ondokuz Mayıs University in Turkey. According to the answers which were given for the knowledge test, it was seen that there was a significant difference on behalf of the post-test, which the worksheets with the applications of 2-d code were used in teaching, between the pre-test success points which were obtained before the application and the post-test success points which were obtained after the application. According to the pre-test results of research, it was determined that the compounds of “KH (f=35) and ZnI2 (f=32)” were written mostly in the correct form. Furthermore, it was seen that none of students wrote the following compounds in the correct form; “SO3, HBrO3, CoCl2.6H2O, KO2, HClO2, NH4H2PO4, H2CO3 and NH4HSO3”. When the correct answers which were given to the post-test of research were reviewed, it was determined that the compounds of “KH (f=41), HgCl2 (f=38), ZnI2 (f=36) and CrCl2 (f=34)” were mostly written in the correct form. Moreover, it was seen according to the pre-test results of research that none of the students could write the compounds of “nickel nitrate, periodic acid, iodic acid, mercury (II) sulphate pentahydrate, hypocholorous acid, chloric acid, sulphurous acid, sodium thiosulphate, silver dichromate, sodium hydrogen phosphate, ammonium hydrogen phosphate and phosphorous acid”. When the answers which were given to the post-test of research were reviewed, it was determined that the most ones were “rubidium hydroxide (f=39), potassium perchlorate (f=37) and hypocholorous acid (f=36); the least ones were “nickel nitrate (f=2), phosphorous acid (f=2), sodium thiosulphate (f=1) and ammonium hydrogen phosphate (f=1)”. If a compound’s chemical formula is known, the connections can be provided to be done between the main subjects of chemistry that the lesson will be done much more attractive with the technology integration in the chemistry teaching as it is considered that an opinion is given about the bond pattern while it is understood how many molecules are available in whichever atom. Keywords: Science teaching, Inorganic compounds, Practice of 2-d cod

Mental Models Regarding the Concepts of “Space,” “Universe” and “Galaxy” Among Secondary School Students

The aim of this study was to identify the mental models of fifth and eighth grade students regarding the concepts of space, the universe, and galaxy. The study was performed using a cross-sectional approach, which is a screening-based study model. This study involved two different groups, which were fifth grade and eighth grade students. We investigated the mental models regarding the concepts of space, the universe, and galaxy among these two groups, and evaluated how these concepts differed between fifth grade and eighth grade students. The study was performed with 116 fifth and eighth grade students from a secondary school in a provincial center in northern Turkey. During the study, students were asked three open-ended questions requiring them to explain the concepts of space, the universe, and galaxy. The study data were analyzed using descriptive analysis. The study results indicated that the level of scientific understanding regarding the concepts of space, the universe, and galaxy was low among both fifth and eighth grade students, although eighth grade students exhibited a slightly higher level of knowledge about these concepts

Synergistic Inhibiting Effect of Phytochemicals in Rheum palmatum on Tyrosinase Based on Metabolomics and Isobologram Analyses

Tyrosinase (TYR) plays a key role in the enzymatic reaction that is responsible for a range of unwanted discoloration effects, such as food browning and skin hyperpigmentation. TYR inhibitors could, therefore, be candidates for skin care products that aim to repair pigmentation problems. In this study, we used a metabolomics approach combined with the isobologram analysis to identify anti-TYR compounds within natural resources, and evaluate their possible synergism with each other. Rheum palmatum was determined to be a model plant for observing the effect, of which seven extracts with diverse phytochemicals were prepared by way of pressurized solvent extraction. Each Rheum palmatum extract (RPE) was profiled using nuclear magnetic resonance spectroscopy and its activity of tyrosinase inhibition was evaluated. According to the orthogonal partial least square analysis used to correlate phytochemicals in RPE with the corresponding activity, the goodness of fit of the model (R2 = 0.838) and its predictive ability (Q2 = 0.711) were high. Gallic acid and catechin were identified as the active compounds most relevant to the anti-TYR effect of RPE. Subsequently, the activity of gallic acid and catechin were evaluated individually, and when combined in various ratios by using isobologram analysis. The results showed that gallic acid and catechin in the molar ratios of 9:5 and 9:1 exhibited a synergistic inhibition on TYR, with a combination index lower than 0.77, suggesting that certain combinations of these compounds may prove effective for use in cosmetic, pharmaceutical, and food industries

Constructible motivic functions and motivic integration

We introduce a direct image formalism for constructible motivic functions. One deduces a very general version of motivic integration for which a change of variables theorem is proved. These constructions are generalized to the relative framework, in which we develop a relative version of motivic integration. These results have been announced in math.AG/0403349 and math.AG/0403350. Main results and statements unchanged. Many minor slips corrected and some details added.Comment: Final versio

The investigation of mutagenic effects of antineoplastic drug muphoran and navelbine in human lymphocyte cultures

Bu çalışmada, değişik kanser tiplerinin kemoterapisinde kullanılan iki antineoplastik ajan olan Navelbine ( Vinorelbine ) ve Muphoran'ın ( Fotemustine ) genotoksik -etkileri araştırılmıştır. Bu amaçla insan lenfosit kültürlerinde kromozom aberasyon ve kardeş kromatid değişim ( SCE ) testleri gerçekleştirilmiştir. Çalışmada Muphoran bileşiği, toz halinde olduğundan steril distile suda çözülerek 2 u-g/ml, 4 fig/ml ve 8 ug/ml dozlarda steril koşullar altmda lenfosit kültürlerine verilmiştir. Kültürlere uygulanan rutin harvest yöntemi ile elde edilen preparatlara giemsa boyama yapılarak kromozom aberasyon frekansı değerlendirilmiştir. Muphoran'ın insan lenfosit kültürlerinde meydana getirdiği kromatid ve kromozom tipte kırıklarda doza bağlı olarak anlamlı bir artış gösterilmiştir. İlacın oluşturduğu toplam aberasyonlar değerlendirildiğinde de doza bağlı olarak anlamlı bir artış görülmektedir. Aynı zamanda Muphoran mitotik indeks oranlarında da doza bağlı olarak anlamlı bir düşüşe sebep olmuştur. SCE preparatlarına ise fluoresan plus giemsa boyama yapılarak SCE'ler değerlendirilmiştir. Muphoran'ın meydana getirdiği SCE oranlarında anlamlı bir artış olduğu gösterilmiştir. İlacm meydana getirdiği kromozom aberasyonları ve SCE'ler açısından kadın ve erkek bireyler arasında anlamlı bir faklılık olmadığı belirlenmiştir. İlaç dozlarına bağlı olarak meydana gelen kromozom hasarları ve SCE'lerde, doz-yanıt ilişkileri açısından bireysel farklılıklar olduğu belirlenmiştir. Diğer kanser ilacı olan Navelbine bileşiği ise, intravenöz solüsyon halinde olduğundan steril distile su ile seyreltilerek 0,5 jag/ml, 1 |ig/ml ve 2 ug/ml dozlarda olmak üzere, steril koşullar altında lenfosit kültürlerine ilave edilmiştir. Kültürlere uygulanan rutin harvest yöntemi ile elde edilen preparatlara giemsa boyama tekniği uygulanarak, kromozom aberasyon frekansı değerlendirilmiştir. Navelbine uygulaması,11 lenfositlerde doza. bağlı olarak artış gösteren anlamlı bir aneuploidiye sebep olmuştur. Bunun yanında, ilacın mitoz durdurucu etkisinden kaynaklanan mitotik indekste artış söz konusu olmuştur. Ayrıca anlamlı olmayan kromatid ve kromozom kırıkları da meydana gelmiştir. SCE testi için ise, preparatlara fluoresan plus giemsa boyama yapılarak, SCE' ler değerlendirilmiştir. Navelbine uygulaması ile doza bağlı olarak SCE oranlarında anlamlı bir artış olduğu gösterilmiştir. İlacm etkisiyle oluşan kromozom aberasyonları ve SCE'lerde, doz-yanıt ilişkisi açısından, bireysel farklılıklar olduğu ortaya konmuştur. Sonuç olarak çalışmamızda genotoksik etkileri araştırılan Navelbine ve Muphoran bileşiklerinin insan lenfosit kültürlerinde kromozom aberasyon ve SCE testlerine pozitif sonuç verdikleri belirlenmiş ve önemli genotoksik etkilerinin olduğu ortaya konmuştur.The purpose of this study, it is aimed to determine the genotoxic effects of two antineoplastic agents that Navelbine ( Vinorelbine ) and Muphoran ( Fotemustine ) are used to treatment of several cancer types. In the peresent work, Muphoran was dissolved in sterile distilled water and added to lymphocyte cultures as 2 ug/ml, 4 u.g/ml and 8 ug/ml. Slides were prepared with routine harvesting method, stained with giemsa and chromosome aberration frequencies were scored for each culture. Muphoran increased the chromatid and chromosome type breaks in dose dependent manner. Total chromosome aberrations were also increased by Muphoran dose dependently. Muphoran significantly decreased the mitotic index ratio in all doses. Concurrently, we applied the SCE method as the second genotoxicity endpoints to lymphocyte cultures. With the Muphoran treatment, the frequency of SCE significantly increased. There were no significant differences among male and female donors with respect to to the frequency of chromosome aberrations and SCE induced by Muphoran. On the contrary, each donor responded differently and significantly that three different doses treated with Muphoran in all whole blood cultures. Other chemotherapeutic drug is Navelbine and it was diluted with sterile distilled water since it was in a solution form. This drug was added to lymphocyte cultures as three doses like 0,5 ug/ml, 1 ug/ml ve 2 ug/ml. In chromosome aberrations ( CA ) assay, Navelbine significantly and dose-dependently increased the aneuploidy induction. The mitotic index was also increased by Navelbine treatment in human lymphocyte cultures. Navelbine induced chromatid and chromosome type breaks but its frequencies were not statistically significant. In SCE assay, Navelbine significantly and dose dependently increased the freguency of SCE's too. Each donor differently andIV significantly responded to Navelbine doses regarding to chromosome aberrations and SCE's. Consequently, it has been suggested in this study that the two drugs Muphoran and Navelbine have induced chromosome aberrations and SCE's in human lymphocyte cultures and may have significant genotoxic effects