Judul: Perception of Farmers in Tilatang Kamang, Agam, West Sumatra to Ricefield Rats and Its Damage
Abstrak: Tikus sawah merupakan hama penting yang dapat menurunkan produksi padi di Indonesia. Kehilangan hasil gabah akibat serangan tikus sawah terjadi hampir di setiap musim tanam. Pengendalian tikus sawah yang sering dilakukan berupa sanitasi, gropyokan, emposan, dan rodentisida. Tujuan penelitian mengetahui persepsi masyarakat tentang peranan tikus sawah serta kerusakan yang ditimbulkannya, selanjutnya dikaitkan dengan metode pengendalian yang diterapkannya. Penelitian dilaksanakan pada bulan Oktober sampai dengan Desember 2020 yang meliputi pengamatan lapang, pengumpulan data, dan analisis data. Pengamatan lapang dilakukan pada petak contoh tanaman padi dengan metode irisan diagonal dengan mengamati 25 sampel tanaman contoh, kemudian dihitung luas dan intensitas kerusakannya. Hasil penelitian menunjukkan bahwa petani percaya bahwa tikus sawah merupakan hama utama yang dapat menurunkan produksi padi. Sebagian besar petani tidak melakukan pengendalian terhadap serangan tikus yang terjadi karena mengikuti kebiasaan turun-menurun, ada juga petani yang melakukan pengendalian dengan menggunakan rodentisida tetapi cara tersebut masih dinilai kurang efektif. Hasil pengamatan luas dan intensitas serangan tikus sawah di Kecamatan Tilatang Kamang diperoleh hasil bahwa serangan tikus sawah pada musim tanam ini termasuk dalam kategori rendah., Ricefield rat’s are the important pest that can reduce the rice production in Indonesia. Yield losses due to ricefield rat attack occur almost every rice growing season. The management of the ricefield rat is often carried out by sanitation, hunting, fumigation, and rodenticides application. The aim of this study was to determine the perceptions of farmers about the existence of ricefield rat and the damage it causes, which is then linked with the control method. The research conducted in October to December 2020, including field observation, data collection, data tabulation analysis. Field observation was carried out on rice field by observing 25 samples of rice clump in a plot using the diagonal transect method. The calculation of the area and intensity of the rat attacks on rice field was then performed. Results have shown that farmers believe that ricefield rats are the main pest that can reduce rice production. However, most of them did not control the population of rats because they followed inherited traditions. Rodenticide application is one of the rat control method used by a small number of farmers, but this method considered less effective. According to the data on the previous growing season, the area and intensity attacks of ricefield rat in Tilatang Kamang was in low category.
Keyword: control method, rodenticide, yield losses

Judul: Daily Catch Pattern of Ricefield  Rat using Trap Barrier System in Kiarasari Village, Compreng, Subang.
Abstrak: Tanaman padi (Oryza sativa L.) merupakan tanaman pangan penting yang menjadi makanan pokok lebih dari setengah penduduk dunia karena mengandung nutrisi yang diperlukan tubuh. Salah satu hama yang menyerang tanaman padi yaitu tikus sawah (Rattus argentiventer), yang hampir di setiap musim tanam menyebabkan kerusakan dan berkurangnya hasil panen. Metode pengendalian yang dapat digunakan yaitu Trap Barrier System (TBS) atau sistem perangkap bubu dan pagar yaitu teknik pengendalian tikus yang mampu menangkap banyak tikus sawah terus menerus selama musim tanam sejak tanam hingga panen. Penelitian ini bertujuan menghitung dan mengidentifikasi tikus yang tertangkap pada TBS, mengidentifikasi sumber serangan dan mengkalkulasi luas serangan tikus sawah. Penelitian dilakukan dari bulan Oktober 2021 hingga Januari 2022, pada 1 hektar lahan sawah dan dilakukan pengamatan tikus yang tertangkap bubu setiap harinya. Semua tikus yang tertangkap perangkap bubu adalah Rattus argentiventer. Total tikus sawah yang diperoleh sebanyak 4.580 ekor, terdiri atas 2.623 ekor jantan (57,37%) dan 1.957 ekor betina (42,73%). Dari jumlah tersebut tikus dewasa dan pradewasa yang tertangkap sebanyak 4.313 ekor (94,17%) dan 267 ekor (5,83%). Intensitas serangan tikus rata-rata 14,92% dan jumlah tikus terbanyak yang tertangkap pada perangkap No. 9 dan 8 yang terletak di sisi timur karena memiliki banyak tempat bersarang yang cocok untuk tikus sawah. Rasio B/C dari penggunaan TBS adalah 38,57 sangat layak untuk diterapkan., Rice (Oryza sativa L.) is an important food crop that, become a staple food for more than half of the world's population because of its richness nutrients. The most important pest that attacks rice crops is ricefield rat (Rattus argentiventer), which causes damage and yield losses in almost every growing season. Trap Barrier System (TBS) one of the most used control methods which combines bamboo fences and multiple live trap, effectively catching many ricefield rats continuously from planting to harvesting. The objectives of this study were to count and identify rats caught in TBS, as well as to identify the source of the attack and its intensity. The study was conducted from October 2021 to January 2022, on one hectare of paddy field and observation the number of the was carried out daily. Based on the morphometrics and body color, all rats caught in multiple live trap is R. argentiventer. Its total 4.580 heads, consisting of male 2.623 heads (57,27%) and female 1.957 heads (42,73%). Of the total catch, 4.313 heads (94,17%) were adults and 267 heads (5,83%) were pre-adults. In addition the average intensity of rats’ attacks was 14,92% and the highest number of rats were caught in traps No. 9 and 8 which were located on the east side and contained many suitable hideouts for ricefield rast. The B/C ratio from the use of TBS was 38,57 suggesting that the method is strongly for implementation.
Keyword: management of rat, Rattus argentiventer, TBS

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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