The development, validity and reliability of TPACK-deep: A technological pedagogical content knowledge scale

The purpose of this study is to develop a TPACK (technological pedagogical content knowledge) scale based on the centered component of TPACK framework in order to measure preservice teachers’ TPACK. A systematic and step-by-step approach was followed for the development of the scale. The validity and reliability studies of the scale were carried out with 995 Turkish preservice teachers. The sample was split into two subsamples on random basis (n1 = 498, n2 = 497). The first sample was used for Exploratory Factor Analysis (EFA) and the second sample for Confirmatory Factor Analysis (CFA). After the EFA, the TPACK-deep scale included 33 items and had four factors. These factors were design, exertion, ethics and proficiency. The Cronbach’s alpha coefficient for the whole scale was found to be .95, whereas the values of Cronbach’s alpha coefficient for individual factors of the scale ranged between .85 and .92. The CFA was conducted within the scope of the validity study of the scale. In this way, this structure of the 4-factor scale was confirmed. In addition, the test-retest reliability coefficient of the scale was calculated as .80. The findings revealed that the TPACK-deep scale was a valid and reliable instrument for measuring TPACK. Consequently, various suggestions were put forward regarding the use the TPACK-deep scale for applied research and for future studies.     

Finite-Element Analysis and Vibration Testing of a Two-Span Masonry Arch Bridge

This paper presents the analytical modeling, modal testing, and finite-element model updating for a two-span masonry arch bridge. An Ottoman masonry arch bridge built in the 19th century and located at Camlihemsin, Rize, Turkey is selected as an example. Analytical modal analysis is performed on the developed 3D finite-element model of the bridge to obtain dynamic characteristics. The ambient vibration tests are conducted under natural excitation such as human walking. The operational modal analysis is carried out using peak picking method in the frequency domain and stochastic subspace identification method in the time domain, and dynamic characteristics (natural frequencies, mode shapes, and damping ratios) are determined experimentally. Finite-element model of the bridge is updated to minimize the differences between analytically and experimentally estimated dynamic characteristics by changing boundary conditions. At the end of the study, maximum differences in the natural frequencies are reduced on average from 18 to 7% and a good agreement is found between analytical and experimental dynamic characteristics after finite-element model updating.     

Partial purification and characterisation of endoglucanase from an edible mushroom, Lepista flaccida

A crude extract was prepared from the fruiting body of Lepista flaccida, an edible mushroom and endoglucanase activity of the extract was increased 14-fold with ammonium sulphate precipitation. Maximum enzyme activity was seen at pH 4.0 and 50 °C when carboxymethylcellulose was used as a substrate. K_0.5 and V_max values of the partially purified endoglucanase were 7.7 mg/ml and 25 ± 0.9 U/mg protein, respectively. The enzyme was quite stable over a broad range of pH (2.0–9.0) at 4 °C. When it was incubated at temperatures between 20 °C and 60 °C for 12 h, it conserved much of its original activity (over 40%). The activity of the enzyme increased by 234 ± 3.6% in the presence of 1 mM Mn²⁺. The endoglucanase was inhibited by EDTA, PMSF, β-ME and DDT. In conclusion, pH and thermal stability of the L. flaccida endoglucanase could make it useful for industrial purposes.     

Growth and development impact of sustainable nutrition education: An experimental study

Healthy societies are formed by learning and maintaining sustainable healthy eating behaviors from childhood. The aim of this study was to determine the effect of short-term sustainable nutrition education on growth and development parameters of preschool children. This study is an experimental design with pretest–posttest control group. This study was carried out in two kindergartens between February 2022 and June 2023 in Turkey. The education group received 4 months of dietary behavior training. The dietary scale and anthropometric measurements were administered at the first and last meetings. Data were analyzed with 95% confidence interval. The study was completed with 174 children. A statistically significant difference was found, especially in body weight (p < 0.05) and body weight percentile values (p < 0.05) in the posttest of the education group. A statistically significant difference (p < 0.05) was found between the groups in the eating behavior scale posttest score. Nutrition education in schools is important in promoting healthy eating habits. Nutrition education improves eating behavior positively. To maintain healthy eating behaviors, however, the continuity of education is necessary. In addition, as growth and development are physical processes, it is recognized that growth and development cannot be assessed by nutrition alone.