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.
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Judul: Pengukuran Hambur Balik Akustik Dasar Laut di Sekitar Kepulauan Seribu Menggunakan Split Beam Echosounder.
Abstrak: The purpose of this research is to compute the backscattering strength of the seabed by measuring volume backscattering strength (SV), bottom surface backscattering strength (SS), and the echo level (EL) from seabed using split beam echosounder. The research was conducted from 29th January to 3rd February 2011, around the Seribu Islands: Pramuka island, Panggang island, Karya island and Semak Daun island, North Jakarta. Acquisition of acoustic data was conducted using the SIMRAD EY 60 instrument. Acoustic data obtained from 9 stations simultaneously with sediment sampling. Acoustic processing data was conducted by Rick Towler program with Matlab based. The SV and SS were analyzed Manik et al, model by using. Sediment sampling station consisted of 9 stations: Pramuka island there are 1 station (Station 1), Karya island there are 2 stations (Station 2, and Station 3), Panggang island there are 3 stations (Station 4, Station 7, Station 9), and Semak Daun island there are 3 stations (Station 5, Station 6, Station 8). Sediment classified based on the sediment texture. Seabed surface sediments were separated into 3 types, they are: sand, mud, and clay. This analysis showed that the location of the 9 stations observation is dominated by sand fraction with the percentage of 80.85%. Mud and clay fractions had the average percentage value of 18.32% and 0.83%, respectively. The backscattering value (SV) of sand substrate ranged -10.62 to -18.51 dB with the average of -13.91 dB, and the muddy sand substrate ranged from -16.58 to -25.42 dB with the average -20.57 dB. The value of SS for the sand substrate ranged from -20.70 to -28.58 dB with the average value of -23.98 dB. Muddy sand substrate has a value of SS in the range of -26.64 to -35.49 dB with the average SS of -30.64 dB, from this research, the classification of seabed type using hydroacoustic technology was possible.
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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.
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