Judul: Growth Rate and Production of Longevity Spinach Plants From Different Parts of Stem Cuttings
Abstrak: Tumbuhan sambung nyawa potensial sebagai hijauan pakan ternak dilihat dari kandungan senyawa nya. Diperlukan optimasi perbanyakan tumbuhan berbasis stek. Tujuan penelitian untuk mengevaluasi tingkat pertumbuhan dan produksi tumbuhan sambung nyawa dari bagian stek batang yang berbeda. Penelitian didesain menggunakan Rancangan Acak Lengkap (RAL) yang terdiri dari 3 perlakuan (stek bawah, stek tengah, dan stek atas). Masing-masing diulang sebanyak 50 kali. Data di analisis menggunakan analisis ragam (ANOVA), jika terdapat beda nyata (p<0,05) dilakukan uji lanjut Duncan. Hasil penelitian menunjukan bahwa perlakuan bagian stek atas dapat meningkatkan jumlah tunas dan waktu awal tumbuh tunas. Perlakuan bagian stek yang berbeda tidak berpengaruh terhadap tinggi tanaman, jumlah daun, jumlah daun layu, produksi tanaman. Tumbuhan sambung nyawa dapat dibudidayakan dari setiap bagian stek dengan kondisi lingkungan yang terkendali., Longvity spinach has potency as animal forage because of its compound content. Optimization of plant propagation based on cuttings is needed. The study aim was to evaluate plant the growth rate and production from different parts of stem cuttings. The study was designed using a completely randomized design (CRD) which consisted of 3 treatments (bottom cuttings, middle cuttings and top cuttings). With repeated 50. Data were analyzed using analysis of variance (ANOVA), if there was a significant difference (p<0.05) Duncan's further test was carried out. The results showed that the treatment of the top cuttings could increase the shoots numbers and the initial time of shoot growth. Different cuttings stem did not affect on plant height, number of leaves, number of wilted leaves, and plant production. In concluded that longevity spinach plants could be cultivated from each part of the cuttings in controlled condition
Keyword: longevity spinach plants, growth, production, stem cuttings

Judul: Evaluation of Growth and Production of Sambung Nyawa at Different Harvesting Ages
Abstrak: Penelitian ini bertujuan mengevaluasi pertumbuhan dan produksi sambung nyawa pada umur panen yang berbeda. Penelitian menggunakan Rancangan Acak Kelompok (RAK) dengan 4 kelompok terdiri dari 3 perlakuan. P1= Umur panen 40 hari, P2= Umur panen 50 hari, dan P3= Umur panen 60 hari. Pubah yang diamati meliputi pertumbuhan tanaman (pertumbuhan tinggi, jumlah cabang, dan jumlah daun) dan produksi tanaman (berat segar, berat kering, dan luas daun). Data dianalisis menggunakan ANOVA dan apabila berbeda nyata (p<0,05) akan dilanjut dengan uji Duncan. Hasil penelitian menunjukkan perlakuan perbedaan umur panen mempengaruhi (p<0,05) pertumbuhan tinggi, jumlah daun, berat segar batang, berat segar daun, total biomassa berat segar, berat kering batang, berat kering daun, berat kering pucuk, dan total biomassa berat kering. Perlakuan perbedaan umur panen tidak mempengaruhi (p>0,05) jumlah cabang, luas daun, luas pucuk, dan berat segar pucuk. Hasil penelitian menunjukkan bahwa perlakuan umur panen 60 hari (P3) memberikan hasil terbaik pada pertumbuhan dan produksi biomassa tanaman sambung nyawa., This study aims to evaluate the growth of plant height and plant production with differentharvesting ages. This study used a Randomized Group Design (RAK) with 4 groups consisting of 3 treatments. P1= 40 days harvest age, P2= 50 days harvest age, and P3= 60days harvest age. The variables observed included plant growth (height growth, number of branches, and number of leaves) and plant production (fresh weight, dry weight, and leaf area). Data were analyzed using ANOVA and if significantly different (p<0.05) willbe continued with Duncan test. The results showed that the treatment of different harvestages affected (p<0.05) the growth of height, number of leaves, stem fresh weight, leaf fresh weight, total biomass fresh weight, stem dry weight, leaf dry weight, shoot dry weight, and total biomass dry weight. The treatment of different harvest ages did not affect (p>0.05) the number of branches, leaf area, shoot area, and shoot fresh weight. Theresults showed that the 60-day harvest age treatment (P3) gave the best results on plant growth and plant biomass production.
Keyword: growth, Gynura procumbens, harvesting, harvesting age, production

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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