Peningkatan Hasil Belajar Mahasiswa Melalui Implementasi Model Pembelajaran Kooperatif Word Square

Tujuan penelitian ini untuk mendeskripsikan peningkatan hasil belajar mahasiswa melalui penerapan model pembelajaran kooperatif Word Square. Populasi dalam penelitian ini adalah 36 mahasiswa jurusan Pendidikan Ekonomi IKIP Gunungsitoli semester II. Penelitian ini merupakan Penelitian Tindakan Kelas dengan prosedur penelitian: persiapan, tindakan, observasi, dan refleksi. Berdasarkan hasil penelitian ditemukan bahwa penerapan model pembelajaran kooperatif work square dalam proses belajar mengajar mata kuliah Dasar- Dasar Akuntansi I dapat meningkatkan hasil belajar mahasiswa Pendidikan Ekonomi semester II IKIP Gunungsitoli. Hal ini terlihat pada hasil belajar siswa pada siklus I sebesar 58, 30% dalam kategori sedang, meningkat pada siklus II mencapai 83, 30% dalam kategori sangat baik. Sehingga disimpulkan bahwa model kooperatif Word Square berpengaruh positif terhadap hasil belajar yaitu peningkatan hasil belajar mahasiswa pada mata kuliah Dasar-Dasar Akuntansi I.

Quantification of Endocrine Disruptors in Locally Available Child Care Products and Their Health Risk Assessment in Fish

Baby care products are mostly used for hygienic and aesthetic purposes worldwide. Phthalates are added as softener and parabens as antimicrobial agents in such products. These two chemicals and their derivatives are included in the list of endocrine disrupting compounds which cause malformation in the production of such hormones that is essential for normal growth and reproduction. Babies are particularly vulnerable to substances that may affect their growth and developmental process. This study was conducted to assess the health risk of children and evaluate dose related endocrine disrupting activity of baby care products by using fish as a model. The level of parabens and phthalates were quantified by using HPLC and GCMS in different brands of baby gift packs and others commonly available synthetic, herbal baby care products and organic oils. DMP and DnOP were detected in 96%, while DEP and DBP detected in only 76% and 57% of subjected products respectively. In the mean value of DMP (1867±180 µg/g), DEP (403.6±52.4 µg/g), DBP (243.7±88.9 µg/g) and DnOP (351.3±34.6 µg/g) were quantified in all products. The mean value of MeP (345.6±63.3 µg/g), EtP (77.83±18 µg/g), PrP (132.7±27.4 µg/g) and BuP (32.9±9.08 µg/g) were quantified in selected products. LOD and LOQ for phthalates and paraben esters were also determined. The total daily exposure dose by using all types of products for phthalates DMP, DEP, DBP was observed to be 32.7, 16.04, 6.34 µg/d respectively for infants and for toddlers it was 23.7, 11.65, 4.73 µg/d respectively. The total paraben exposure by using all type of products for MeP, EtP, PrP, BuP was 543.5, 125.7, 261.7, 53.3 µg/d for infants and 394.9, 91, 188.7, 39.3 µg/d for toddlers respectively. Fish were exposed to phthalates, parabens and their mixture for a period of 30 days under semi-static laboratory conditions at a dose based on mean values quantified in baby care products. The endocrine disruptive activity of phthalates, parabens and their mixture were evaluated by hematological analysis, cytogenotoxicity in terms of micronucleus test, comet assay and differential gene regulation of HPGL axis in the control (without exposure) and treated fish groups. The significant maximum decrease in RBC, PCV, Hb and PLT were observed in all treated groups as compared to the control. Fluctuations in MCV, MCHC, MCH values with respect to control were also noted in fish of all exposed groups. Mean frequencies of all nuclear anomalies were high in phthalate mixture group and paraben mixture group (32.16±13.80) and (25.60±10.80), respectively with reference to individual phthalate and paraben esters. In mean value of anomalies in all treated groups, lower value was of DBP group (16.33±4.92) whereas the greater mean value was of 4 mixture group (62.8±27.2) due to the cumulative effect of all exposed chemicals in the mixture. In other nuclear anomalies, lobed nuclei and karryorehixes were recorded in the highest frequencies. Karyolysis was the least observed nuclear alterations in almost all treated groups. The DNA damage was detected in the peripheral blood cell of juvenile fresh water fish Labeo rohita using comet assay. The maximum increase in tail length was observed in phthalate mixture group (315±90.51 px) as compared to other individual phthalates and control (0.73±0.59 px). There was also a remarkable difference in tail DNA% of control (7.16±6.32%), paraben mixture group (33.78±13.99%) and 4 mixture treated group fish (47.70±19.92%) at p<0.05 that clearly indicated DNA damage in the exposed fish was chemical specific and concentration dependent. A tail moment of 4 mixture group (88.90±58.8) was statistically significantly different from control (0.06±0.38) at p<0.05. The differential expression of the genes related to HPGL axis revealed statistically highly significant differences at p<0.05 in the expression levels of VTG, GnRHR, CYP19a and CYP19b of Labeo rohita exposed to phthalates and parabens esters. The Vtg was highly expressed in paraben mixture group (27.3±12.5) as compared to the control (8.24±4.89) whereas it was a down-regulation in fish exposed to phthalate and phthalate mixture groups. There was a down-regulation of Cyp19b in all treated group fish with respect to the control fish but it was 84-fold greater than the control in paraben mixture. The expression of the GnRHR gene in phthalate mixture exposed fish was 3.23-fold higher than the control fish and was down-regulated in all stressed group fish. There was a down-regulation in the expression of Cyp19a genes in DBP group fish while there was an up-regulation in phthalate mixture, paraben mixture and 4 mix groups as compared to the control group fish. In conclusion, the daily exposure dose of phthalates and parabens by using each leave on and wash off products calculated in this study was high so regular use of these products on daily basis can lead to carcinogenicity. The significant DNA damage and cytogenotoxicity observed in all the treatment fish groups due to chronic exposure of phthalates and parabens are suggestive of DNA damage and genetic makeup alteration in children by using baby care products contaminated with phthalates and parabens.