Judul: Measurement of acoustic backscattering strength of sea-bottom with single and multi beam echosounder
Abstrak: Underwater acoustic instruments has been an indispensable tool to study the ocean. Application of acoustic such as sonar technologies to bottom acoustics study has made significant advances over recent decades. The sonar systems evolved from single beam systems to more sophisticated digital ones like multi beam echo sounder. In this paper, both systems of single beam echo sounder (SBES) and multi beam echo sounder (MBES) were applied to detect and measure acoustic backscattering strength of sea-bottom. Sampling sediment was taken for ground truth data using bottom sampler. For SBES, data collection was carried out in Seribu Islands, Jakarta. Data were collected using CruzPro PcFF80 FishFinder with operating frequency 200 kHz. The algorithm to compute underwater signal using this instrument had been developed by Manik (2011). For MBES, data collection was carried out in Buyat Bay, North Sulawesi Province. Data were collected using Elac Seabeam 1050D MBES with operating frequency 180 kHz and processed with MBSystem version 5 software. For SBES, the results showed the value of surface backscattering strength (SS) for sand varied from -18.68 dB to -17.39 dB, silty sand -23.25 dB to -19.32 dB, and clayey sand was -19.83 dB. The echo level (EL) for sand varied from 131.4 dB to 138.2 dB, silty sand 133.5 dB to 135.4 dB, and for clayey sand was 136.5 dB (using source level (SL) 163 dB). For MBES, the SS for silty sand varied from -24.26 dB to -20.56 dB, and sandy silt -25.12 dB to -24.30 dB.
Keyword: 

Judul: Quantification and Characterization of Bottom Acoustic Backscattering In Seribu Islands – Jakarta
Abstrak: Seabed has a very important role as the habitat for various living creatures, and critical part of aquatic environment. Nowadays, new methods to obtain information on bottom types, sediment characteristics and underwater vegetation in shallow water by using echosounder has flourished. In this paper, normal incident of acoustic waves were used to determine values of bottom backscattering strength (volume backscattering strength (Sv), surface backscattering strength (SS) and echo level (EL)). Sediment properties (acoustic impedance, bulk density, porosity, sound speed and sediment composition) were used to explain the acoustic measurement results. Data collection was carried out in Seribu Islands, Jakarta using SIMRAD EY 60 scientific echosounder systems with operating frequency 120 kHz. The results show that the average value of volume backscattering strength (Sv) for sand is -13,23 dB and silty sand is -21,15 dB. The average value of surface backscattering strength (SS) for sand is -23,30 dB and silty sand is -31,22 dB. The average value of echo level (EL) for sand is 177,94 ± 8,61 dB and silty sand is 167,23 ± 6,07 dB (Source Level (SL) for split beam transducer ES 120-7C series is 214 dB). These acoustics values were then used as input for PCA analysis to cluster seabed characteristics. It’s shown that the acoustic technique can be used to identify and classify sediments and map sediment provinces. Key words: sediment
Keyword: 

Judul: Infeksi Virus Parainfluenza Pada Anjing
Abstrak: Virus parainfluenza anjing termasuk famili Paramyxoviridae, berbentuk pleomorf dengan ukuran bervariasi (bergaris tengah antara 100-500 nm), berpembungkus peka ether, berisi genom RNA dan secara serologis mempunyai kesamaan dengan virus SV-5 kera; dikenak sebagai salah satu kausa penting dari sindrom "kennel cough". Infeksinya dapat mengenai anjing semua umur yang belum pernah terinfeksi atau mendapatkan vaksinasi mengakibatkan gejala klinis ringan yang terbatas pada traktus respirasi atu infeksi yang secara klinis tidak memperlihatkan gejala nyata. Gejala klinis yang nampak setelah masa inkubasi (1-5 hari) terlewati berupa batuk yang tidak berat selama beberapa hari, berbagai tingkat tonsilitis dan pharyngitis dan kadang-kadang ditemukan kenaikan temperatur rektal antara 1-2 derajat C dari temperatur normal rat-rata. Anjing terinfeksi mengandung virus pada traktus respirasi bagian atas dan bawah serta limfonoduli sampai hari ke 9 setelah infeksi. Penyebaran virus antar anjing terjadi secara aerogen.
Keyword: