Judul: Dampak ENSO dan ENSO Modoki terhadap Variabilitas Curah Hujan di Indonesia
Abstrak: Variabilitas curah hujan Indonesia dipengaruhi oleh fenomena El Nino-Southern Oscillation (ENSO) dan ENSO Modoki. Saat fenomena El Nino (La Nina), terjadi kenaikan (penurunan) suhu permukaan laut di bagian tengah hingga selatan Samudera Pasifik. Saat El Nino (La Nina) Modoki, peningkatan (penurunan) suhu permukaan laut terkonsentrasi pada bagian tengah Samudera Pasifik, sedangkan penurunan (peningkatan) suhu terjadi di bagian barat dan timur. Penelitian ini bertujuan untuk mengetahui dampak dari ENSO dan ENSO Modoki terhadap variabilitas curah hujan di Indonesia. Data yang digunakan adalah Indeks Nino 3.4 untuk mewakili peristiwa ENSO, El Nino Modoki Index (EMI) untuk mewakili peristiwa ENSO Modoki, dan data curah hujan bulanan dari CHIRPS. Metode yang digunakan adalah analisis korelasi, analisis temporal, serta analisis komposit dan spasial. Hasil korelasi antara curah hujan Indonesia dengan Indeks Nino 3.4 lebih signifikan daripada korelasi curah hujan dengan EMI pada tingkat kepercayaan 90%. Respon anomali curah hujan terhadap ENSO Modoki lebih lemah dibandingkan pada saat ENSO. Saat El Nino Modoki, anomali curah hujan bernilai negatif tetapi lebih lemah daripada saat terjadi El Nino dimulai dari bulan Juni-November. Saat La Nina Modoki, anomali curah hujan bernilai positif tetapi lebih lemah terlihat dibandingkan saat La Nina pada bulan Juli-Agustus. Angin di ketinggian 850 hPa yang bergerak dari timur ke barat (barat ke timur) lebih kuat saat El Nino (La Nina) dibanding saat El Nino (La Nina) Modoki. Anomali OLR bernilai positif (negatif) saat El Nino (La Nina) menunjukkan rendahnya (tingginya) jumlah awan yang menyebabkan terjadi hujan di wilayah Indonesia, sedangkan saat El Nino Modoki dan La Nina Modoki anomali OLR bernilai lebih lemah pada dua kejadian tersebut.
Keyword: curah hujan, ENSO, modoki, OLR

Judul: El Niño Modoki dan Pengaruhnya Terhadap Perilaku Curah Hujan Monsunal di Indonesia
Abstrak: This study aims to investigate El Niño Modoki phenomenon and its influence to the monsoonal rainfall behavior over Indonesia. The study is also intended to identify the differences between the El Nino Modoki and the well-known El Nino events, referred in this study as Conventional El Niño. By using correlation analysis, it is shown that the El Nino Modoki Index, known as EMI, is strongly correlated with SST anomaly index in Nino-4 region. The correlation coefficient value is 0.57, which is higher than the EMI’s correlations with other SST anomaly indices from different Nino regions, i.e. Nino-1.2, Nino-3 and Nino-4. Temporal analysis on both Nino-4 index and EMI by using Power Spectral Density shows a different strength in the temporal cycle of both indices, where Nino-4 data demonstrates a strong 4-5 year interannual cycles, while EMI is dominated by 6–8 years cycles. This is consistent with the result of Wavelet analysis that indicates four years interannual cycles of Nino-4 index and nearly decadal (~10 years) cycles of EMI data. The composite of seven El Nino Modoki events in 1986/87, 1990/91, 1992/93, 1994/95, 2002/2003, 2004/2005, and 2009/2010, generally shows that the El Nino Modoki events indicated by the raise of EMI exceeding its defined threshold usually occurred from July to March. It is shown by clear characteristics of growing phase starting from March or April until January, and continued by decreasing phase around February. Based on the results of regression analysis, the El Nino Modoki strongly influence monsoonal rainfall over Sumbawa Besar, Makassar, and Banjar Baru during both June-July-August (JJA) and September-October-November (SON) periods, over Lampung only during JJA, and Indramayu during SON. The use of EMI which includes information about the SST anomaly around Indonesia led to a significant cross-correlation values between monsoonal rainfall anomaly and EMI with only maximum of one month lag time.
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Judul: Synthesis of Chicken Eggshells-Based β-Tricalcium Phosphate Bioceramics and Their Biocompatibility Test as A Tooth Filler
Abstrak: Preservation of alveolar bone following tooth extraction is an important step in dental practices before dental implant placement. This study reported synthesis of β-Tricalcium Phosphate (β-TCP) bioceramics and its biocompatibility test as a tooth filler to maintain the desired alveolar ridge dimension and stimulate the bone healing processes in the area of tooth loss. β-TCP bioceramics was resulted directly from precipitation of calcinated chicken eggshells as calcium source and phosphoric acid. The corresponding β-TCP was mixed with chitosan 2% to get β-TCP pellet for biocompatibility testing. Biocompatibility testing of β-TCP on lower incisor was performed in rabbits and sheep as animal model. In this study, the x-ray diffraction (XRD) profiles showed that 1000 oC calcinated chicken eggshells correspond to calcium oxide (CaO). There was also transformation phase of CaO into Ca(OH)2 observed after more than three months stored. The XRD profiles proved that obtained β-TCP bioceramics by precipitation has the same pattern with that of reference data base and commercial β-TCP. Fourier transform infrared (FTIR) spectra were completely consistent with the result of crystallization processes observed by XRD measurements. Moreover, the purity of the product shown by the atomic absorption spectroscopy (AAS) resulted in Ca/P ratio of 1.48 which was closed to that of standard β-TCP ceramics. The repeatable XRD peaks patterns and FTIR spectra obviously showed the sample reproducibility. Sheep’s alveolar socket that is filled with the corresponding β-TCP demonstrated the expected results. The x-ray radiograph of sheep’s jaw indicated no change on mesio-distal of the edentulous area. Moreover, the histological results were completely consistent with the x-ray radiograph and macroscopic result which is proved by the formation of new bone. In the contrary with sheep’s result, histological results showed no tooth growth on rabbit proved by the presence of lipid and collagen on the extraction site. This result did not correspond to the x-ray radiograph and macroscopic results that demonstrated the tooth growth and erupted tooth. It is clear that the corresponding β-TCP could minimize the bone loss and maintain the dimension of alveolar ridge.
Keyword: β-tricalcium phosphate, chicken eggshells, rabbit, sheep, tooth filler