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    Effects of 2,4-dichlorophenoxyacetic acid formulation on medulla spinalis of Poecilia reticulata: A histopathological study
    (Pergamon-Elsevier Science Ltd, 2009) Uyanikgil, Yigit; Yalcinkaya, Murat; Ates, Utku; Baka, Meral; Karakisi, Hatice
    This study investigated the possible effects of a commonly used foliar herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) formulation on medulla spinalis of lebistes. Fish were exposed to 2,4-D (15, 30, 45 ring L-1), behavioral changes were monitored. Fish were fixed, histopathological examination was carried out on sections taken from the upper parts of the fish body. Histopathology showed increase in neuronal loss, swelling indicating formation of intracellular edema, vacuolization noticed as the formation of vacuoles within or adjacent to cells, deformation in the Nissl granules, pyknosis and gliosis in medulla spinalis. Behavioral changes were decreased general activity, grouping, shortness in breath. sudden rotations and jumping, loss of equilibrium and colour. In conclusion, this commercial formulation of 2,4-D is considerably neurotoxic to lebistes. Fish constitute the last link in the chain of the feeding cycle in aquatic eco-system, number of studies investigating acute and chronic neurotoxicity of various herbicides in fish should be increased. (C) 2009 Elsevier Ltd. All rights reserved.
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    Effects of 2,4-dichlorophenoxyacetic acid formulation on medulla spinalis of Poecilia reticulata: A histopathological study
    (Pergamon-Elsevier Science Ltd, 2009) Uyanikgil, Yigit; Yalcinkaya, Murat; Ates, Utku; Baka, Meral; Karakisi, Hatice
    This study investigated the possible effects of a commonly used foliar herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) formulation on medulla spinalis of lebistes. Fish were exposed to 2,4-D (15, 30, 45 ring L-1), behavioral changes were monitored. Fish were fixed, histopathological examination was carried out on sections taken from the upper parts of the fish body. Histopathology showed increase in neuronal loss, swelling indicating formation of intracellular edema, vacuolization noticed as the formation of vacuoles within or adjacent to cells, deformation in the Nissl granules, pyknosis and gliosis in medulla spinalis. Behavioral changes were decreased general activity, grouping, shortness in breath. sudden rotations and jumping, loss of equilibrium and colour. In conclusion, this commercial formulation of 2,4-D is considerably neurotoxic to lebistes. Fish constitute the last link in the chain of the feeding cycle in aquatic eco-system, number of studies investigating acute and chronic neurotoxicity of various herbicides in fish should be increased. (C) 2009 Elsevier Ltd. All rights reserved.
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    The eTIMSS and TIMSS Measurement Invariance Study: Multigroup Factor Analyses and Differential Item Functioning Analyses with the 2019 Cycle
    (Assoc Measurement & Evaluation Education & Psychology, 2024) Yalcinkaya, Murat; Atilgan, Hakan; Dascioglu, Selim; Aydin, Burak
    In this study, measurement invariance and differential item functioning (DIF) studies of the TIMSS 2019 4th and 8thgrade mathematics and science achievement tests were conducted for the country groups participating in both TIMSS and eTIMSS. The study sample consisted of 9560 responders of the first booklet of the 2019 cycle. Multiple Group Confirmatory Factor Analysis (MGCFA) was utilized to test measurement invariance, and Mantel-Haenszel (MH), Logistic Regression (LR), and SIBTEST were used for the DIF analyses. The measurement invariance results indicated strict invariance between groups for all tests which included 111 items in total. In the DIF analyses, for the 4th and 8th -grade mathematics tests, only three items showed moderate DIF with MH, and four items showed DIF with SIBTEST. For the 4th -grade science test, one item showed moderate DIF with both MH and SIBTEST. However, in the 8th -grade science test, no items showed DIF with MH and LR methods, while four items showed moderate DIF with SIBTEST. Overall, MH and SIBTEST techniques were in agreement, whereas LR method produced inconsistent results and showed disagreement with these two methods. The results of the measurement invariance analysis and the LR method were consistent and indicated equivalency of TIMSS and e-TIMSS scores.