Judul: Internal Wave Detection and Quantification Using SIMRAD EK80 Broadband Echosounder Instrument in Padang Bay Waters Bali
Abstrak: Internal wave adalah peristiwa yang terjadi di laut dangkal dan laut dalam, dimana kemunculan internal wave hanya dapat terjadi jika kolom air terstratifikasi akibat adanya perbedaan densitas massa air. Penelitian ini bertujuan mendeteksi peristiwa internal wave, serta mengukur nilai acoustic backscatter dari internal wave terjadi di Selat Lombok. Data yang digunakan adalah hasil pengukuran instrument broadband echosounder SIMRAD EK80 frekuensi 200 kHz tipe pulsa continuous wave (CW) dengan data pendukung elevasi muka air, suhu, salinitas, dan densitas dari Conductivity Temperature Depth (CTD) “yoyo” selama 24 jam. Nilai hambur balik didapatkan dengan analysis menggunakan perangkat lunak Sonar5-Pro. Echogram menunjukkan adanya pembentukan nonlinearinternal wave disertai dengan adanya turbulent terjadi pada saat gelombang pasang membawa massa air dengan densitas berbeda melewati topografi kasar di Selat Lombok. Nilai backscatter hasil segmentasi berentang dari -75 dB sampai -59 dB., Internal waves are events that occur in shallow sea and deep sea, where the appreanced of internal waves can only occurs if the water column is stratified due to differences in water mass density. This study aimed to detect internal wave events, as well as measure the acoustic backscatter value of internal waves occurring in the Lombok Strait. The data used is the measurement result of SIMRAD EK80 broadband echosounder instrument with frequency of 200 kHz continuous wave (CW) pulse type with supporting data for water level elevation, temperature, salinity, and density from Conductivity Temperature Depth (CTD) “yoyo” for 24 hours. The backscatter value was obtained by analysis using the Sonar5-Pro software. Echogram showed the formation of nonlinear internal waves accompanied by the presence of turbulence that occur when high tidal waves carry water masses from different density through rough topography in Lombok Strait. The backscatter value of the segmentation results range from -75 dB to -59 dB.
Keyword: Backscatter, Broadband, Continuous Wave, Internal Wave, Tidal Wave

Judul: Pendekatan matematis pada pembangkitan gelombang internal di Selat Makassar
Abstrak: In Makassar strait, which is located between the islands of Kalimantan and Sulawesi, the fascinating phenomena of internal waves can be observed. Internal waves are gravity waves that oscillate within, rather than on the surface of, a fluid medium. Internal waves occur in the interior of water in seas, which exist due to a difference in density of the lower and upper layer of the fluid. Typical characteristics of internal waves are their large wavelength and amplitude. This research aims to derive a dispersion relation based on the basic equations of two-layers fluid, to determine the internal waves in the Makassar Strait, and to create a simulation of generation of the internal waves using the software Mathematica. The results show that the generation mechanism of these internal waves can be formulated based on the Kelvin-Helmholtz dispersion relation for a two-layers fluid. This dispersion relation can also be used as classification criteria of instability of internal waves. Emphasis is given to the types of instability, i.e. temporal and spatial instability. Temporal stability occurs if current velocity in the upper part of fluid is less than its critical velocity. For the spatial instability, internal waves in Makassar strait can be approximated for both layers as deep water waves. The spatially stable region is reached when the frequency of the lower part of fluid is smaller than the critical frequency, or when the frequency of the upper part of fluid is larger than the critical frequency.
Keyword: Sea current, Generation of internal waves, Pycnocline

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