Judul: Fluktuasi Ketinggian Tropopause Tropis Dengan Menggunakan Analisis Komponen Utama Dan Spektral
Abstrak: Data ERA-Interim ECMWF dengan parameter ketinggian geopotensial level 100 mb di kawasan tropis selama 30 tahun (Januari 19981 – Desember 2010) digunakan untuk mengidentifikasi fluktuasi tinggi tropopause kawasan tropis. Pola – pola fenomena pembangkit fluktuasi ketinggian tropopause di wilayah kajian teridentifikasi dengan menggunakan metode Analisis Komponen Utama (PCA), analisis spektrum, dan analisis spektrum silang. Tiga komponen utama mampu merepresentasikan 90.4% dari variabilitas total fluktuasi ketinggian tropopause di wilayah tropis. Analisis spektral pada ketinggian komponen utama menunjukkan bahwa fluktuasi ketinggian tropopause tropis didominasi oleh periode 12 bulan dan 45 bulan yang merupakan variasi insolasi orbital dan El Niño-Southern Oscillation (ENSO), sedangkan fenomena lainnya Quasi-Biennial Oscillation (QBO) dan Madden-Julian Oscillation (MJO). Fenomena tersebut memiliki pengaruh yang merata untuk wilayah tropis. Komponen utama kedua menunjukkan bahwa fluktuasi tinggi tropopause di lintang 15o - 20o lebih dipengaruhi oleh variasi insolasi musiman. Komponen utama ketiga dipengaruhi oleh fenomena Semi-Annual Oscillation (SAO) yang berkorelasi tinggi di wilayah ekuator. Respon setiap fenomena tertentu memiliki selisih waktu (time lag) terhadap tinggi tropopause.
Keyword: Analisis Komponen Utama, analisis spektral, geopotensial, insolasi musiman, insolasi orbital

Judul: Identifikasi Fluktuasi Ketinggian Tropopause di Kawasan Pasifik Tropis
Abstrak: The 30-years (January 1981 – December 2010) ERA-Interim data issued by ECMWF (Europe Center for Medium Range Weather Forecasting) is used for identifying tropopause height fluctuation in tropical Pacific region. Principle component and spectral analysis is done in order to identify the main pattern of tropopause height fluctuation as generator in the region. The result has shown that the predominant fluctuation trigger is periodical 45-month ENSO. Meanwhile insolation fluctuation due to earth orbital position has placed second with 12- month period after ENSO occurrence. The 20-month oscillation period of QBO (Quasi Biennial Oscillation), periodical 6-month variation of SAO (Semi Annual Oscillation), and 6-month period of MJO (Madden Jullian Oscillation) give weaker influence on tropopause height fluctuation in the region than that of ENSO and insolation. Eigen vector distribution from principle component shows that these five oscillations are very influential and dominant in tropical west Pacific as response of interaction of the five oscillations with Walker circulation in tropical Pacific.
Keyword: Bogor Agricultural University (IPB), Spectral, Walker circulation, Tropopause height fluctuation, Principle component analysis

Judul: Gene Editing  of Two Cyanide Synthesis-related Genes in Cassava using CRISPR/Cas9
Abstrak: Cassava (Manihot esculenta) contain toxic quantities of cyanogenic glucoside. Reducing the potentially toxic cyanogenic glucoside levels in cassava could be achieved by gene editing through Clustered Regularly Interspaced Short Palindromic Repeats – CRISPR associated protein 9 (CRISPR/Cas9), a high- precision genome editing technique in plants. Two cassava UDP- glucosyltransferase (UGT) paralogs, UGT85K4 and UGT85K5, are the genes catalyzing the synthesis of cyanogenic glucosides in plants. The study aimed to construct the CRISPR/Cas9 recombinant vector carrying single guide RNA (sgRNA) to edit UGT85K4 and UGT85K5 genes, and transform sgRNA CRISPR/Cas9 construct into KU50 cassava calli. Five sgRNAs were designed, considering the on/off target efficiency score and GC content. Those sgRNAs were ligated into pRGEB32 plasmid and introduced to competent Escherichia coli DH5a. The PCR colony and DNA sequencing were performed to verify the sgRNA insert. The amplicons showed the expected band size of recombinant vector (180 bp). Based on sequencing results, only one sgRNA was successfully ligated into the plasmid that will be used to edit the UGT85K5 gene. The sgRNA CRISPR/Cas9 construct in pRGEB32 plasmid was successfully transformed into Agrobacterium tumefaciens and introduced into KU50 cassava calli through co-cultivation. The overgrowth of Agrobacterium occurred after the co-cultivation phase.
Keyword: CRISPR/Cas9, Cyanogenic glucoside, Gene editing, sgRNA