Analisis Pelemahan Multipel pada Data 2D Seismik Laut “IS†dengan Metode Transformasi Radon

Multipel termasuk noise pada data seismik laut yang mengganggu dalam interpretasi sehingga perlu untuk diminimalisir keberadaannya. Multipel dapat menimbulkan ambiguitas pada data seismik laut sehingga tidak dapat menggambarkan kondisi bawah permukaan yang sebenarnya. Salah satu metode yang digunakan untuk penelitian ini adalah metode transformasi radon yang bertujuan untuk melemahkan multipel. Pada penelitian ini diperoleh data seismik laut “IS†terdapat  water bottom multiple  pada time 600 - 1400 ms dengan waktu tempuh dua kali lipat dari waktu seabed.  Hasil yang diperoleh setelah diterapkan metode transformasi radon menunjukkan multipel dapat terlemahkan dengan baik sehingga penampang seismik dapat menggambarkan kondisi bawah permukaan yang sebenarnya

Validation of a Single-Nucleotide Polymorphism-Based Non-Invasive Prenatal Test in Twin Gestations : Determination of Zygosity, Individual Fetal Sex, and Fetal Aneuploidy

We analyzed maternal plasma cell-free DNA samples from twin pregnancies in a prospective blinded study to validate a single-nucleotide polymorphism (SNP)-based non-invasive prenatal test (NIPT) for zygosity, fetal sex, and aneuploidy. Zygosity was evaluated by looking for either one or two fetal genome complements, fetal sex was evaluated by evaluating Y-chromosome loci, and aneuploidy was assessed through SNP ratios. Zygosity was correctly predicted in 100% of cases (93/93; 95% confidence interval (CI) 96.1%-100%). Individual fetal sex for both twins was also called with 100% accuracy (102/102; 95% weighted CI 95.2%-100%). All cases with copy number truth were also correctly identified. The dizygotic aneuploidy sensitivity was 100% (10/10; 95% CI 69.2%-100%), and overall specificity was 100% (96/96; 95% weighted CI, 94.8%-100%). The mean fetal fraction (FF) of monozygotic twins (n = 43) was 13.0% (standard deviation (SD), 4.5%); for dizygotic twins (n = 79), the mean lower FF was 6.5% (SD, 3.1%) and the mean higher FF was 8.1% (SD, 3.5%). We conclude SNP-based NIPT for zygosity is of value when chorionicity is uncertain or anomalies are identified. Zygosity, fetal sex, and aneuploidy are complementary evaluations that can be carried out on the same specimen as early as 9 weeks' gestation