Judul: Induksi variasi somaklonal dan  seleksi in vitro menggunakan peg untuk identifikasi varian kacang tanah yang toleran cekaman kekekringan
Abstrak: Drought stress tolerance of peanu cultivar having certain mechanism without decreasing the yield needed to be developed. Somaclonal variation has been succesfully used to obtain variant lines with improved drought stress tolerance. In this case, induction of somaclonal variation is followed by in vitro selection on selective medium containing polyethylene-glycol (PEG).
Keyword: Somaclonal variation, In vitro selection, PEG 6000, Drought tolerance, Tolerance mechanism without intensive root growth, Proline, Polietilena glikol

Judul: In vitro Selection For Drought Resistance On Rice
Abstrak: The rice demand is recently increasing , on the other hand the production is decreasing. It is caused by the long dry season due to the seasonal change. In addition, a lot of productive land has changed into industrial and settlement which in return minimize the number of productive land. To overcome this 2 varients with high yield and drought-stress resistant as in IR 64 variety should be produced. In this attemt, mutative induction combined with in vim culture and in vitro selection on the Gajahmungkur, Topwuti and IR 64 variants has been conducted and has yielded several somaclones which show the genetic variation. Through evaluation and characterization for the drought resistant using PEG 20% (BM 6000), several somaclone assumed to be drught resistant have been obtained. Subsequently, to find , out the mechanisme of the respective genotype toward the drought stress resistance, root penetration and proline content analysis at the somaclone have been $ conducted. From the evaluation, 23 Gajah mungkur somacloncs, 9 Towuti somaclones and 13 Ir 64 somaclones have been obtained as the ones with the high proline content. The drought stress treatment to the assumed drought stress resistent it is obtained 9 somaclones from Towuti, 5 from Gajahmungkur and 8 from IR 64 with the better characteristics under drought test than that of the main plants. Shorter plant with more shoots are obtained from Gajahmungkur but the seeds ripe earlier. From Tohti variants, more shoots and higher plants along with the more grain are obtained. From variety of IR 64 , somaclone which can produces seeds during the drought is obtained, meanwhile this does not happen with the plant originated from seed. The plants resulted from the selection produce more qualified shoot and grain than that of the main plants.
Keyword: 

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.
Keyword: