Pengembangan Perangkat Pembelajaran Teorema Pythagoras Dengan Media Berbantuan Komputer

Penelitian ini bertujuan untuk menghasilkan perangkat pembelajaran matematika SMP dengan media berbantuan komputer pada materi teorema Pythagoras yang valid, praktis, dan efektif ditinjau dari prestasi belajar matematika dan mathematics self-efficacy siswa. Penelitian ini merupakan penelitian pengembangan yang terdiri atas empat tahap, yaitu tahap define, design, develop, dan disseminate. Subjek coba dalam penelitian ini terdiri atas 9 siswa untuk uji coba kelompok kecil dan 30 siswa untuk uji coba lapangan. Penelitian dilaksanakan di SMP Negeri 2 Banyubiru, Kabupaten Semarang. Instrumen penelitian yang digunakan adalah lembar validasi, lembar penilaian guru, lembar penilaian siswa, lembar observasi kegiatan guru, lembar observasi kegiatan siswa, dan kuesioner mathematics self-efficacy. Kriteria keberhasilan dalam penelitian ini adalah jika banyaknya siswa yang memperoleh nilai tes akhir melebihi KKM lebih dari 75% dan siswa yang memiliki skor mathematics self-efficacy pada kriteria tinggi atau sangat tinggi lebih dari 75%. Hasil penelitian menunjukkan bahwa perangkat pembelajaran yang dikembangkan adalah valid, praktis, dan efektif ditinjau dari prestasi siswa dan skor mathematics self-efficacy mereka

Flow and Heat Transfer during an Expansion Stroke in a Composite Fluid/Porous System

The purpose of this study is to analyze the fluid flow and heat transfer in a pipe partially filled with porous media and provided with a flat piston during an expansion stroke. In addition to the Navier-Stokes equation for the fluid region, Brinkman-Forchheimer-Lapwood-extended Darcy’s model is introduced into the numerical solver to simulate flow and heat transfer in the porous insert. The heat transfer in porous media is studied by using the assumption of local thermal equilibrium. The discretization procedure is based on Control-Volume-based Finite Element Method. The coupled pressure-velocity equations are solved using the SIMPLER algorithm. This investigation concerns the hydrodynamic characteristics, using the Reynolds numbers and the porosity effects, and the heat transfer characteristics using the heat capacity and the thermal conductivity ratios effects

Coexistence of K-ras mutations and HPV infection in colon cancer

BACKGROUND: Activation of the ras genes or association with human papillomavirus infection have been extensively studied in colorectal cancer. However, the correlation between K-ras mutations and HPV in colorectal cancer has not been investigated yet. In this study we aimed to investigate the presence of K-ras mutations and their correlation with HPV infection in colon cancer. METHODS: K-ras mutations were analyzed by a mutagenic PCR assay and digestion with specific restriction enzymes to distinguish the wild-type and mutant codons. HPV infection was analyzed by PCR amplification and hybridization with specific probes by Southern blotting. Stattistical analyses were performed by the chi-square and Fisher's exact tests RESULTS: HPV gene fragments were detected in 43 tumors and 17 normal tissue samples. HPV 18 was the prevalent type in the tumor tissue. A mutation at codon 12 of the K-ras gene was present in 31 patients. 56% of the HPV-positive tumors also harbored a K-ras mutation. Codon 13 mutations were not observed. These data indicate that infection with high risk HPV types and mutational activation of the K-ras gene are frequent events in colorectal carcinogenesis. CONCLUSION: Our findings suggest that mutational activation of the K-ras gene is a common event in colon carcinogenesis and that HPV infection may represent an important factor in the development of the premalignant lesions leading to the neoplastic phenotype