Judul: Economic Valuation of the Great Yellow-crested White Cockatoo (Cacatua galerita)
Abstrak: Kakatua putih besar jambul kuning (Cacatua galerita) merupakan primadona dalam perdagangan satwa liar. Penelitian ini bertujuan untuk menghitung valuasi ekonomi Cacatua galerita dengan pendekatan harga pasar, willingness to pay (kesediaan membayar), dan biaya pemeliharaan, serta membandingkan ketiga metode tersebut. Penelitian dilakukan dengan studi literatur dan pemantauan sosial media dalam pendekatan harga pasar, pendekatan kesediaan membayar dilakukan wawancara kepada 100 pengunjung Taman Margasatwa Ragunan (TMR) secara accidental sampling, dan pendekatan biaya pemeliharaan dilakukan wawancara kepada pengelola TMR dan penangkaran Mega Bird and Orchid Farm (MBOF). Hasil penelitian menunjukkan valuasi ekonomi Cacatua galerita dengan pendekatan harga pasar, kesediaan membayar, dan biaya pemeliharaan berturut-turut sebesar Rp35.547.204/ekor, Rp3.656.900/ekor, dan Rp7.119.001/ekor. Metode pendekatan terbaik untuk menghitung valuasi ekonomi Cacatua galerita yaitu pendekatan harga pasar yang ditinjau dari valuasi ekonomi yang dihasilkan, efektivitas, serta efisiensi biaya yang relatif murah dalam pengambilan dan analisis data., The great yellow-crested white cockatoo (Cacatua galerita) is a favorite in the wildlife trade. This research aims to calculate the economic value of Cacatua galerita using the market price approach, willingness to pay, and maintenance costs, as well as comparing the three methods. The research was carried out using literature studies and social media monitoring using the market price approach, the willingness to pay approach carried out interviews with 100 visitors to the Ragunan Wildlife Park (TMR) using accidental sampling, and the maintenance cost approach carried out interviews with TMR managers and the Mega Bird and Orchid Farm (MBOF). The research results show that the economic valuation of Cacatua galerita using the market price approach, willingness to pay, and maintenance costs is Rp. 35,547,204/head, Rp. 3,656,900/head, and Rp. 7,119,001/head. The best approach method for calculating the economic valuation of Cacatua galerita is the market price approach in terms of the resulting economic value, effectiveness and relatively lowcost efficiency in data collection and analysis.
Keyword: biaya pemeliharaan, harga pasar, kakatua putih besar jambul kuning, kesediaan membayar, valuasi ekonomi

Judul: Management Training and Utilization of Palm Cockatoo as Display Animal in TMII Jakarta Bird Park
Abstrak: Kakatua raja merupakan salah satu spesies burung dilindungi di Indonesia yang dikonservasi dan dimanfaatkan sebagai satwa peraga untuk menarik minat pengunjung di Taman Burung TMII Jakarta. Penelitian ini bertujuan mengidentifikasi manajemen pelatihan, menganalisis persepsi dan preferensi responden, serta menghitung nilai ekonomi berdasarkan kesediaan membayar untuk pemanfaatan kakatua raja di taman Burung TMII Jakarta. Penelitian ini dilaksanakan di Taman Burung TMII Jakarta pada Maret sampai April 2022. Metode yang digunakan adalah observasi lapang, wawancara, survey, dan studi literatur. Hasil penelitian menunjukkan bahwa manajemen pelatihan kakatua raja terdiri dari tiga tahap yaitu adaptasi, bonding, dan latihan. Persepsi responden cenderung setuju mengenai pemanfaatan dan konservasi kakatua raja di Taman Burung TMII Jakarta. Nilai total kesediaan membayar yang bersedia responden keluarkan terhadap interaksi kakatua raja sebagai satwa peraga adalah sebesar Rp 13.474 dengan rataan jumlah pengunjung 7268 orang per bulan dengan total pendapatan ekonomi sebesar Rp 97.926.737/bulan., Palm cockatoo (Probosciger aterrimus) is one of the protected bird species in Indonesia that is conserved and used as a display animal to attract visitors at TMII Jakarta Bird Park. This study aims to identify training management, analyze respondents’perceptions and preferences, and calculate the economic value based on willingness to pay (WTP) for the use palm cockatoo at TMII Jakarta Bird Park. This research was conducted at TMII Jakarta Bird Park on March to April 2022. The methods used in this research are field observations, interviews, surveys, and literature studies. The results showed that the palm cockatoo management training consisted of three stages, namely adaption, bonding, and training. Respondents’perceptions tend to agree about the use and conservation of palm cockatoo at TMII Jakarta Bird Park. The total value of willingness to pay that respondents are willing to spend on the interactions of the palm cockatoo as a display animal is Rp. 13.474. with an average number of visitor of 7268 people/month with a total economic income of Rp 97.926.737/month.
Keyword: Palm cockatoo, perception, preference, training management, willingness to pay

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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