Judul: Habitat Suitability Mapping of Aren (Arenga pinnata Merr.) in Central Bangka Regency, Bangka Belitung Islands Province
Abstrak: Aren (Arenga pinnata Merr.) merupakan salah satu spesies tumbuhan yang berasal dari famili Arecaceae. Salah satu daerah yang memiliki sebaran aren yaitu Kabupaten Bangka Tengah. Penelitian bertujuan mengidentifikasi sebaran spasial aren, kesesuaian habitat, faktor yang memengaruhi distribusi aren, dan strategi pengembangan aren di Kabupaten Bangka Tengah. Data kehadiran aren didapatkan melalui survey dengan stratified sampling. Data titik kehadiran aren dan variabel lingkungan diolah dalam software Maximum Entropy untuk menghasilkan model dan nilai kesesuaian habitat aren. Aren banyak ditemukan pada area dengan kriteria ketinggian 0-50 mdpl, kemiringan lereng 0-8%, nilai NDVI antara 0,42-1, nilai NDMI >1, jarak dari sungai 0-500 m, jenis tanah kambisol oksik, podsolik kromik, dan menyebar di tutupan lahan perkebunan. Model kesesuaian habitat yang diperoleh bersifat baik (AUC = 0,902) dengan pembagian kelas yaitu tidak sesuai (0 ha), kurang sesuai (127.971 ha), cukup sesuai (50.363 ha), sesuai (24.678 ha) dan sangat sesuai (4.7867 ha). Jenis tanah, ketinggian, dan curah hujan menjadi faktor yang berpengaruh dalam kesesuaian habitat aren. Strategi pengembangan budidaya dapat dilakukan menggunakan sistem agroforestri., Aren (Arenga pinnata Merr.) is one of the plant species from the Arecaceae family. One of the regions that have sugar palm distribution is Central Bangka Regency. The study aimed to identify the spatial distribution of sugar palm, habitat suitability, factors affecting sugar palm distribution, and sugar palm development strategies in Central Bangka Regency. Data on sugar palm presence was obtained through a survey with stratified sampling. Data of sugar palm presence points and environmental variables were processed in Maximum Entropy software to produce models and values of habitat suitability of sugar palm. Aren are found in areas with altitude criteria of 0-50 mdpl, slope of 0-8%, NDVI value between 0.42-1, NDMI value >1, distance from river 0-500 m, soil type of oxic cambisol, chromic podsolik, and spread in plantation land cover. The habitat suitability model obtained is good (AUC = 0.902) with class divisions of unsuitable (0 ha), less suitable (127,971 ha), moderately suitable (50,363 ha), suitable (24,678 ha) and very suitable (4,787 ha). Soil type, altitude, and rainfall are factors that influence the suitability of sugar palm habitat. Cultivation development strategy can be done using agroforestry system.
Keyword: aren, habitat, kesesuaian

Judul: Palm Ethnobotany in Beruas Village Community, Simpang Katis District, Central Bangka Regency
Abstrak: Aren (Arenga pinnata Merr.) merupakan spesies palma multiguna yang tersebar hampir di seluruh kawasan Indonesia, salah satunya di Desa Beruas. Penelitian ini bertujuan untuk mengidentifikasi profil masyarakat, bentuk pemanfaatan, kearifan lokal, dan tumbuhan berguna yang berada di sekitar tegakan aren. Pengambilan data dilakukan menggunakan metode wawancara secara mendalam, observasi partisipatif, dan dokumentasi. Hasil penelitian menunjukan bahwa seluruh petani aren di Desa Beruas berjenis kelamin laki-laki dengan dominan usia 36-45 tahun (dewasa akhir, KU III). Masyarakat memanfaatkan aren sebagai bahan pangan seperti gula aren dan kolang-kaling serta sebagai kerajinan tangan seperti sapu ijuk. Masyarakat memiliki kearifan lokal dalam menentukan aren yang menghasilkan banyak air melalui morfologi aren. Petani aren juga menggunakan pengawet alami seperti akar ube-ube kuning dan daun karamuang untuk memperpanjang masa simpan air nira. Spesies tumbuhan berguna yang pada umumnya ditemukan pada kelekak yaitu durian, nangka, manggis, cempedak, karet, dan kelapa., Sugar palm (Arenga pinnata Merr.) is a multipurpose palm species that is spread almost throughout Indonesia, one of which is in Beruas Village and Teru Village. This research aims to identify community profiles, forms of use, local wisdom, and useful plants located around sugar palm stands. Data collection was carried out using in-depth interview methods, participant observation, and documentation. The research results show that all sugar palm farmers in Beruas Village and Teru Village are male with a dominant age of 36-45 years (late adulthood, KU III). People use sugar palm as a food ingredient such as palm sugar and palm fruit and as a handicraft such as palm fiber brooms. The community has local wisdom in determining palm trees that produce a lot of water through palm morphology. Sugar palm farmers also use natural preservatives such as yellow ube- ube roots and Karamuang leaves to extend the shelf life of palm juice. Useful plant species that are generally found in kelekak are durian, jackfruit, mangosteen, cempedak, rubber, and coconut.
Keyword: aren, Kearifan lokal, kelekak, pemanfaatan aren

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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