Judul: Waterleaf production and quality with organic and inorganic fertilizer
Abstrak: Three consecutive field experiments had been conducted at the IPB experimental station (Bogor, Indonesia), in March-July 2011 to study the effect of two types of fertilizer on waterleaf [Talinum triangulare (Jacq.) Willd.] production and quality in wet (March-May 2011) and dry (May-July 2011) seasons; while laboratory analysis was conducted from April to December 2011. The first experiment was in wet season and consisted of two sets of treatment, namely different rates of organic [cow manure (ton/ha) + guano (kg/ha) + hull ash (ton/ha), i.e. 6.1 + 75.6 + 2.7, 9.2 + 151.2 + 4.1, 12.3 + 226.8 + 5.5, 15.4 + 302.4 + 6.8, and 18.4 + 378.0 + 8.2] and inorganic [urea (kg/ha) + SP-36 (kg/ha) + KCl (kg/ha), i.e. 50 + 20 + 50, 75 + 40 + 75, 100 + 60 + 100, 125 + 80 + 125, and 150 + 100 + 150] fertilizer. The second experiment was in dry season and consisted of two sets of treatment, namely different rates of organic and inorganic fertilizer (same as the first experiment). The third experiment was in dry season and consisted of four sets of treatment, namely different rates of organic (6.1 + 75.6 + 2.7, 12.3 + 226.8 + 5.5, and 18.4 + 378.0 + 8.2; the fertilizers and units were as above) and inorganic (50 + 20 + 50, 100 + 60 + 100, and 150 + 100 + 150; the fertilizers and units were as above) fertilizer, and organic and inorganic fertilizer residue (without fertilizer re-application). The experimental design for each set was randomized block design. Since fertilizer rates did not significantly affect the variables, means value of each set were compared by using t-student’s test. Generally, the result from these research suggested that (1) In wet season, waterleaf with organic fertilizer did not have any difference in shoot production; while in dry season, these treatments resulted in higher shoot production compared to those with inorganic fertilizer; (2) Waterleaf antioxidant capacity of organic and inorganic treatments were not significantly different in the same planting season; (3) The primary (vitamin C) and secondary (flavonoid) metabolites with antioxidant functions were higher in dry season compared to those in wet season; (4) Biosynthesis pathway of waterleaf phenolic compounds in wet season was different from that in dry season. It was suspected that phenolic compounds were synthesized predominantly via phenylpropanoid pathway in wet season and via acetate-malonate pathway in dry season; (5) Without organic or inorganic fertilizer re-application in the new planting season, yield of waterleaf shoot decreased approximately 26-50 % but did not degrade the quality.
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Judul: Protein and anthocyanin production of waterleaf shoot (Talinum triangulare (Jacq.) Willd) with nitrogen+potassium application and harvest interval
Abstrak: The research was conducted in Leuwikopo, Dramaga, Bogor, Indonesia from November 2009 until December 2010 to increase waterleaf shoot protein and anthocyanin production with nitrogen+potassium application and harvest interval. The research consisted of 4 experiments. The first experiment was conducted from November 2009 until Februari 2010 to study the effect of different levels of nitrogen+potassium and harvest interval on waterleaf shoot protein and anthocyanin production. The result showed that combination of 100 kg urea/ha + 100 kg KCl/ha and 15 days harvest interval gave the highest protein production (4.72 g/plant). The highest anthocyanin production was resulted by treatments of 100 kg urea+ 100 kg KCl/ha (152.23 μmol/plant) and 10 days harvest interval (165.27μmol/plant), but it was not influenced by interaction between level of N+K fertilizer and harvest interval. The second experiment was conducted from April until July 2010 to study the effect of different harvest intervals and splitting application of nitrogen+potassium on waterleaf shoot protein and anthocyanin production. The result showed that combination of 15 days harvest interval and three times fertilization with total dosages of 150 kg urea+ 150 kg KCl/ha produced the highest protein production (13.90 g/plant) and anthocyanin (250.61 μmol/plant) of marketable shoots. The third experiment was conducted from April until July 2010 to study the effect of foliar application of nitrogen+potassium and harvest interval on waterleaf shoot. The result showed that 4 times of foliar application and 100 kg urea + 100 kg KCl/ha of basal fertilizer produced the highest shoot protein (5.69 g/plant) and anthocyanin production (109.44 μmol/plant) on the waterleaf which harvested every 15 days interval. The fourth experiment was conducted from October until December 2010 to study the effect of soil and foliar applications of nitrogen+potassium fertilizer on waterleaf shoot protein and anthocyanin production. The result showed that the highest protein and anthocyanin production of waterleaf shoot for 75 days were produced by 100% soil application of N+K; protein production was 16.98 g/plant while anthocyanin production was 170.27μmol/plant. From those 4 experiments, it can be concluded that to obtain the highest protein and anthocyanin production, waterleaf must be harvested every 15 days from 30 until 75 days after planting. Furthermore, waterleaf must be fertilized in three steps with 100 kg urea + 100 kg KCl/ha at planting, 25 kg urea + 25 kg KCl/ha at 30 and 60 days after planting. The correlation between protein or anthocyanin content with the growth and other physiologis components were not consistent.
Keyword: leafy vegetable, protein, anthocyanin, fertilizer, harvest, Waterleaf Shoot, Talinum triangulare

Judul: Persamaan Geodesik Black Hole dengan Metrik Kerr 4+1 Dimensi dalam Koordinat Waktu Kosmik
Abstrak: Persamaan geodesik black hole dengan metrik Kerr 4+1 dimensi dalam koordinat waktu kosmik merupakan interpretasi lain dari persamaan geodesik black hole dengan metrik Kerr 4+1 dimensi, dimana acuan waktu yang digunakan diubah dari koordinat waktu wajar (proper time) ke dalam koordinat waktu kosmik (cosmic time). Waktu kosmik merupakan koordinat waktu yang dimana pengamat bergerak mengikuti ekspansi dari alam semesta. Penelitian ini merekonstruksi persamaan geodesik black hole dengan metrik Kerr 4+1 dimensi yang telah ditemukan pada penelitian sebelumnya menjadi persamaan geodesik yang memiliki fungsi terhadap dimensi waktu (t). Hasil akhir dari transformasi persamaan dapat digunakan sebagai bahan studi pustaka untuk penelitian lebih lanjut mengenai persamaan geodesik black hole dalam koordinat waktu kosmik.
Keyword: Dimensi ekstra, Metrik Kerr, Persamaan geodesik, Waktu kosmik