Judul: Respon pertumbuhan dan serapan dan hara Cu, Fe, Mn dan Zn pada tanaman kangkung dan bayam dengan pemberian pupuk organik dan anorganik
Abstrak: Mineral nutrients generally categorized as macronutrients and micronutrients. Nutrients Cu, Fe, Mn and Zn were essential for plant because these nutrients have an important role in plant metabolism. The aim of the research was to know the growth response and absorption of micro nutrients Cu, Fe, Mn and Zn of Kangkong and Spinach with organic (cow dung and worm cast) and inorganic fertilizers application (Urea, SP-36, KCI). P1 treatment was the mixed of soil and inorganic fertilizer (Urea 200 kg/ha, SP-36 100 kg/ha, KCI 100 kg/ha for the Kangkong; Urea 200 kg/ha, SP-36 195 kg/ha, and KCI 120 kg/ha for the Spinach). P2 treatment was the mixed of soil and cow dung (30 ton/ha for kangkong and 10 ton/ha for spinach); P3 treatment was the mixed of soil and worm cast of Eisenia foetida (30 ton/ha for kangkong and 10 ton/ha for spinach) and P4 as control. The result showed the given organic and inorganic fertilizers did not affect to all vegetative growth that observed. Nevertheless, plant with organic fertilizer application showed higher average values to all vegetative parameters that observed compared to inorganic fertilizer or control plants. Plant with organic fertilizer treatment also showed higher absorption of macronutrients and micronutrients compared to inorganic and control treatment. Kangkong plants with cow dung treatment showed absorption of micronutrients Fe, Mn, Zn and Cu respectively 511.8 ppm, 123.1 ppm, 93.2 ppm, and 13.4 ppm. Spinach plants with cow dung treatment showed absorption of Fe, Mn, Zn and Cu respectively 354.4 ppm, 104.7 ppm, 102.7 ppm and 12.8 ppm. Control plant showed low average values to all vegetative parameters that observed.
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Judul: Growth of Water Spinach and Spinach Due to the Application of Inorganic Liquid Fertilizer in the Hydroponic System
Abstrak: Hidroponik adalah salah satu metode alternatif dalam budidaya sayur, metode ini tidak memerlukan area yang luas. Produksi dari hidroponik dapat ditingkatkan dengan pemenuhan nutrisi yang tepat. Penelitian ini bertujuan menganalisis efek penambahan pupuk anorganik cair pada larutan hara AB mix terhadap pertumbuhan tanaman kangkung dan bayam. Rancangan penelitian yang digunakan adalah Rancangan Acak Kelompok. Perlakuan yang diamati adalah konsentrasi larutan hara yang terdiri dari 3 taraf. Perbandingan air, larutan A, larutan B, dan pupuk cair (v/v) yaitu P0 (kontrol) = 1000:5:5:0, P1 =1000:5:5:5, dan P2 = 1000:5:5:15. Parameter yang diamati adalah tinggi tanaman, jumlah daun, jumlah cabang, luas daun, berat segar, berat kering, dilakukan juga uji kualitatif kandungan nitrat daun. Hasil penelitian menunjukkan bahwa perlakuan P0 memiliki pertumbuhan tercepat, sedangkan pertumbuhan paling lambat terlihat pada P2. Uji nitrat daun P2 menunjukkan hasil yang negatif. Perlakuan P0 juga memiliki berat segar dan berat kering tanaman yang paling tinggi dibanding dua perlakuan lainnya. Penambahan pupuk anorganik cair tidak dapat meningkatkan pertumbuhan pada kangkung dan bayam., Hydroponics is an alternative method in vegetable cultivation, this method does not require a large area. Hydroponics production can be increased with the fulfilment of proper nutrition. This research aimed to analyze the effect of adding liquid inorganic fertilizer to the AB mix nutrient solution on water spinach and spinach growth. This research used a Randomized Block Design. The treatments observed were the concentration of nutrient solution which consisted of 3 levels. The treatments were mixed of water, solution A, solution B, and liquid fertilizer (v/v), namely P0 (control) = 1000:5:5:0, P1 =1000:5:5:5, and P2 = 1000:5:5:15. The parameters observed were plant's height, number of leaves, number of branches, leaves area, leaves nitrate content, and plant fresh and dry weights. The results showed that the P0 treatment had the fastest growth, while the slowest growth was seen in P2. The leaf nitrate test of P2 plants showed negative results. The P0 treatment also had the highest fresh and dry weights per plant compared to the other two treatments. The addition of liquid inorganic fertilizer did not increase the growth of water spinach and spinach.
Keyword: AB mix, hydroponics, liquid inorganic fertilizer, spinach, water spinach

Judul: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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