Judul: Analysis of Youth Interest in Working as Farmers of Pamelo Oranges (Citrus maxima) in Tambakmas Village, Sukomoro Subdistrict, Magetan Regency
Abstrak: Desa Tambakmas merupakan desa sentra jeruk pamelo yang sebagian besar penduduknya bekerja sebagai petani jeruk pamelo. Petani jeruk pamelo didominasi berumur tua. Rendahnya minat pemuda terhadap pekerjaan sebagai petani jeruk pamelo dapat menghambat regenerasi petani dan keberlanjutan usahatani tersebut. Penelitian ini bertujuan untuk (1)menganalisis pendapatan usahatani jeruk pamelo di Desa Tambakmas, (2)menganalisis persepsi pemuda Desa Tambakmas terhadap pekerjaan sebagai petani jeruk pamelo, (3)menganalisis faktor-faktor sosial ekonomi yang memengaruhi minat pemuda Desa Tambakmas terhadap pekerjaan sebagai petani jeruk pamelo. Metode analisis data terdiri dari analisis pendapatan, skala likert, dan regresi logistik biner. Hasil analisis menunjukkan R/C ratio lebih dari satu dan rata-rata pendapatan usahatani jeruk pamelo menguntungkan, tetapi lebih rendah daripada UMK Kabupaten Magetan tahun 2021 dan 2022. Persepsi pemuda Desa Tambakmas setuju terhadap pekerjaan sebagai petani jeruk pamelo yang memiliki pendapatan positif, lingkungan kerja nyaman, membuka lapangan pekerjaan, meningkatkan status sosial, tidak merusak lingkungan, tetapi terdapat risiko dalam pengelolaannya. Faktor-faktor sosial ekonomi yang berpengaruh signifikan pada taraf nyata lima persen adalah jenis kelamin, status pernikahan, lama pendidikan, pendapatan orang tua, latar belakang pekerjaan orang tua pemuda, dan persepsi pemuda terhadap pekerjaan sebagai petani jeruk pamelo. Berdasarkan hal tersebut, diperlukan pelatihan dan manajemen risiko budidaya jeruk pamelo untuk meningkatkan minat pemuda., Tambakmas village is one of the pamelo oranges village where most of the residents work as pamelo orange farmers. Pamelo orange farmers in this village are dominated by old farmers. Some youths are not interested in working as pamelo orange farmers which constrains the regeneration and sustainability of pamelo oranges farming. This study aims to (1) analyze the income of pamelo orange farmers in Tambakmas village, (2) analyze the perception of the youth of Tambakmas village towards work as a pamelo orange farmers, (3) analyze of socio-economic factors that influence the interest of the youth of Tambakmas village towards work as a pamelo orange farmers. Data analysis methods are income analysis, likert scale, and binary logistic regression. The result of the analysis show that the R/C ratio is more than one and income average of pamelo orange farming is profitable, but lower than the UMK in Magetan Regency in 2021 and 2022.The youth of Tambakmas village have the perception of agreeing to work as a pamelo orange farmers, which is indicated by a positive value income, a comfortable work environment, creating jobs, increasing of social status, and not damaging the environment, but there are risks in its management. The factors of socio-economic that have a significant level of five percent are gender, marital status, length of education, parents income, the work background of the youth’s parents and the youth’s perception of work as a pamelo orange farmers. Based on this, training and risk management of pamelo oranges cultivation are needed to increase youth interest.
Keyword: binary logistics regression, farmer regeneration, income analysis, likert scale, youth perception

Judul: Analysis of Efficiency and Income of The Pamelo Orange Farming (Case Study: Bageng Village, Gembong District, Pati Regency
Abstrak: Jeruk pamelo merupakan buah unggulan di Kabupaten Pati dengan sentra produksi berada di Desa Bageng. Penurunan hasil produksi jeruk pamelo berdampak pada produktivitas yang mengalami penurunan. Penelitian ini bertujuan untuk menganalisis efisiensi teknis, faktor-faktor yang memengaruhi produktivitas, dan pendapatan usahatani jeruk pamelo. Metode yang digunakan adalah analisis fungsi produksi stochastic frontier, analisis pendapatan dan R/C rasio. Hasil penelitian menunjukkan rata-rata efisiensi teknis sebesar 0,73 yang artinya usahatani jeruk pamelo sudah efisien secara teknis. Pendidikan dan pengalaman usahatani secara signifikan memengaruhi inefisiensi teknis. Penggunaan pupuk kandang, pupuk NPK, pupuk urea, dan jumlah pohon secara signifikan meningkatkan produktivitas. Rata-rata pendapatan petani jeruk pamelo sebesar Rp12.587.903,76 per tahun per hektar dengan R/C rasio 1,48 yang artinya usahatani jeruk pamelo menguntungkan dan layak diusahakan., Pamelo orange is a superior fruit in Pati Regency with the production center located in Bageng Village. The decrease in yield of pamelo oranges has an impact on the productivity which has decreased. This research aims to analyze the technical efficiency, the factors that affect the productivity, and the income of the pamelo orange farm. The method used is stochastic frontier production function analysis, income analysis and R/C ratio. The result of the research shows that the average technical efficiency is 0.73 which means that the pamelo orange farming is technically efficient. Farming education and experience significantly influence technical inefficiency. The use of manure, NPK fertilizer, urea fertilizer, and the number of trees significantly increased productivity. The average income of pomelo orange farmer is Rp12,587,903.76 per year per hectare with an R/C ratio of 1.48, which means that the pamelo oranges farming is profitable and feasible.
Keyword: cobb-douglas, produktivitas, R/C rasio, regresi, stochastic frontier

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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