Judul: Amonium Nitrat dan Kalsium Klorida Berpengaruh Terhadap Keragaan Planlet Stevia rebaudiana
Abstrak: Stevia is used as an alternative natural sweetener that contains glycosides, with the level of sweetness 300 times higher than that of cane sugar. It presents no calorie, very low glycemic index, and is safe to be consumed. Propagation of stevia can be done through tissue culture technique. One of the problems in tissue culture of stevia is the low plantlet vigor. This research aimed to increase stevia plantlet vigor by modifying concentration of ammonium nitrate (NH4NO3) and calcium chloride (CaCl2) on ½ WP medium. The results show that NH4NO3 and CaCl2 concentrations affected the growth and the performance of stevia plantlets. Normal concentration of NH4NO3 and twice concentration of CaCl2 show best combination to improve the plantlet vigor of stevia
Keyword: Bogor Agricultural University (IPB), plantlet vigor, NH4NO3, CaCl2, Stevia rebaudiana

Judul: Modifikasi Unsur Hara Makro untuk Peningkatan Keragaan Planlet Stevia rebaudiana dalam Kultur In Vitro
Abstrak: Stevia rebaudiana a shrub that originated from Paraguay, has been developed in many developed countries as natural sweetener to substitute sugarcane. Previous researches that focus on plantlet’s vigor by adding paclobutrazol and applying different light intensities had unsatisfied results. This research aimed to increase stevia plantlet’s vigor by modifying macro nutrients contained in MS and WP media. MS and WP media were used with macro nutrients at half stength, normal and double strength. After four weeks of culture, WP media promoted the growth to better conditions than MS media. WP media was superior in some parameters such as the height, number of nodes, number of roots, class of leaf color, size of leaf and biomass fresh weight, although some parameters such as stem diameter, number of buds, and survival rate ware not significantly different. Increasing the concentration of macro nutrients tended to give negative effect on the parameters. WP media with half-strength macro nutrient in general resulted in a better vigor of stevia plantlet’s
Keyword: plantlet vigor, macro nutrient, modification, Stevia rebaudiana

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