Judul: Growth, shoot production, and metabolite content of waterleaf (talinum triangulare (jacq.) willd) with repeated organic fertilization.
Abstrak: Waterleaf (Talinum triangulare (Jacq.) Willd) can be consumed as vegetable by consuming its shoot. Waterleaf is known as functional vegetable because the shoot contains some bioactive compounds to maintain human health. The purpose of this research was to investigate the effect of organic fertilizer combination to growth, production and metabolite content of waterleaf i.e. vitamin C, flavonoid, and peroxidase (POD) activity in the first and second planting season and organic fertilizer residue with repeated harvesting. This research was conducted at Leuwikopo Darmaga Bogor and Plant Analysis and Chromatography Laboratory, Department of Agronomy and Horticulture, IPB in November 2012-May 2013. The organic fertilizers were cow manure (CM), rock phosphate (RP) and rice-hull ash (HA). The fertilizer was combined into four combinations, CM + RP, CM + HA, RP +HA, and CM +RP +HA; with one control (without fertilizer). Treatment was arranged with randomized completely block design with three replications. Two experiments were set in the second season, i.e. the effect of organic fertilizing in the second season and the effect of organic fertilizer residue. The result showed that organic fertilizer gave same effect on growth, shoot production and metabolite content of waterleaf. Vitamin C was positively correlated to flavonoid content while flavonoid and vitamin C content was negatively correlated to K. Low rain intensity in the second harvest increased POD activity while flavonoid content decreased that was caused by precursor competition in flavonoid and lignin biosynthesis. Lignin biosynthesis is catalyzed by POD enzyme. Application of organic fertilizer in the second season increased growth, production, and metabolite content of waterleaf shoot. Cow manure + rock phosphate + rice-hull ash treatment gave the highest increase of shoot production compared to control treatment. Organic fertilizer residue from first season gave the same effect on growth and shoot production compared to control treatment. There was no significant difference effect between residual effect and organic fertilizer added in the second season. Growth and shoot production in the second season was lower than first season that was caused by low of rain intensity that inhibited the growth of waterleaf. The same condition also occurred in waterleaf metabolite content. Vitamin C content decreased in the second season while flavonoid content increased.
Keyword: flavonoid, POD, repeated harvesting, Talinum triangulare, vitamin C

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: Invers dari Matriks Tridiagonal Jacobi
Abstrak: Suatu matriks berukuran n×n dinamakan matriks tridiagonal jika untuk . Karya ilmiah ini memberikan algoritma yang mudah untuk menemukan invers ( dari matriks tridiagonal Jacobi yang simetrik dan nonsimetrik. Setiap elemen pada matriks tridiagonal ini adalah bilangan real. Terdapat 3 lema dan 2 teorema untuk menentukan . Lema pertama menunjukkan persamaan utama dalam membuktikan lema-lema dan teorema-teorema selanjutnya. Invers dari matriks yang simetrik dibuktikan oleh lema kedua yang menunjukkan elemen-elemen baris ke- dari . Selanjutnya, lema kedua dilengkapi dengan teorema pertama yang menunjukkan elemen-elemen dengan . Invers dari matriks yang nonsimetrik dibuktikan oleh lema ketiga yang menunjukkan elemen-elemen dengan dan elemen-elemen dengan dibuktikankan oleh teorema kedua.
Keyword: symmetric, nonsymmetric, matrix