This study aims to identify the effect of STEM practices, integrated into Science courses in 6th grades of middle schools, on students' academic achievement, problem-solving skills, their attitudes towards STEM, and their interest level of STEM fields. The population of the study consists of 6th-grade students enrolled in a middles school in the 2018-2019 academic year. During the research, Academic Achievement Test, STEM Attitude Scale, STEM Career Interest Survey, and Problem Solving Inventory were applied to experimental and control groups as pre and post-tests by quasi-experimental research design. In data analysis, a statistics package program was used. Results of the study showed that the Academic Achievement Test scores of experimental groups that received STEM practices were seen to be higher than that of the control group to which the constructivist approach was applied. The difference was observed to be meaningful. Also, when the post-test scores of the STEM Attitude Scale, STEM Career Interest Survey, and Problem Solving Inventory were compared, a meaningful difference was found between the experimental and control group.

This study aims to compare the growth estimation of narrow-clawed crayfish (

This study, some metals (zinc, copper, lead and cadmium) were analyzed in liver, muscle and gills of Sander lucioperca (Linnaeus, 1758) caught from the Hirfanlı Dam Lake in December 2007. The highest concentrations were found in liver (zinc:32.5 μg/g, lead:10.73 μg/g, copper:5.85 μg/g, cadmium:0.76 μg/g) of Sander lucioperca. It was seen that the accumulation of zinc, lead and cadmium primarily took place in liver followed by muscles and gills. It was observed that copper is mainly accumulated in liver followed by gill and mucsles.

In this study, the concentrations of arsenic and boron were determined in the water and the sediment, as well as in the muscle tissues of Squalius cephalus, Alburnoides bipunctatus, Barbus plebejus and Capoeta tinca from Emet Stream. The fish samples were caught in May 2011 and September 2012. The metal concentrations in the water samples were as follows: arsenic was 137.1-1002 µg L, and boron was 2421-14490 µg L. The metal concentrations in the sediment samples were as follows: arsenic was 14.51-3317.1 mg kg, and boron was 14.22-1014.01 mg kg. The mean tissue concentration of arsenic was lower than the TFC and WHO limits. Boron has been identified in fish tissues at concentrations between 0.26 and 2.96 mg kg. The bioaccumulation in the muscle tissues of all fish species caught from Emet Stream did not exceed the limit values.

In this study, Nickel (Ni), Lead (Pb), Cadmium (Cd) and Chromium (Cr) concentrations were determined in muscle, liver, kidney, gills and gonads of Indian mackerel (Rastrelliger kanagurta) collected from Karachi fish Harbour, Karachi coast, Pakistan, during August 2006 and December 2011. Generally, the fish showed the highest level of Ni (2.26+0.89 µg g -1 ), Pb (1.45+0.40 µg g -1 ), Cd (2.07+0.75 µg g -1 ) and Cr (1.52+0.69 µg g -1 ) in the liver. The studied metals were the most abundant in the liver than the other organs of the fish. The amount of metal accumulation in fish tissues was evaluated in terms of human health. It was seen that bioaccumulations in muscle tissues of the fish caught from Karachi coast of Pakistan did not exceed the limit values.