Judul: Peran Ekstrak Tempe terhadap Kinerja Organ TestisAnak Tikus Usia Prapubertas
Abstrak: Tempe is a fermented soy product from Rhizopus sp., and it contain phytoestrogens derived from the isoflavones group. This research was conducted to study the potential of tempe extract to the reproduction performance of prepuberty male rats (Rattus norvegicus). Rats were divided into two groups, which were control group without given any therapy and treatment group that has been given 0.25 g/kgBW/day of tempe extract from the age of 21-days old until 48 days-old. At the age of 28, 42, and 56 days, samples of testes, and blood were collected from male rats. The parameters observed were the wet and dry weight, the total of DNA and RNA, and testosterone concentration. Data were analysed using an Independent Samples T-Test method with 95% confidence interval. Results showed that increasing of the rates of testosterone hormone at the age of 42 and 56 days, increasing in total of RNA at the age 28 and 42 days, but decreasing in total of DNA rats given phytoestrogen therapy.
Keyword: total of DNA and RNA, testosterone, testes, tempe, phytoestrogens

Judul: Peran ekstrak tempe pada tikus jantan usia prapubertas terhadap perkembangan reproduksi
Abstrak: Phytoestrogens are substances in plants and have similar structure to estrogen. Tempe is a processed soy beans that are source of phytoestrogens. This study was conducted to determine the role of tempe extract in prepubertal male rats (weaning) to the growth of the reproductive system. A total of 18 male rats weaning age of 21 days were divided into 2 groups, control and treatment groups that were given a soybean extract 6.25g/KgBW at age 21 to 48 days. Parameters observed were testicular weight, reproductive hormones, sperm presence, and body weight. Data were collected at the time of male rats aged 28, 42, and 56 days. Data was analyzed using t-test with 95% confidence interval (α=0.05). The results showed that tempe extract in prepubertal male rats influenced in increased body weight of male rats aged 42 and 56 days, body weight gain of male rats at the age of 28–24 days, estrogen level at the age of 42 days and the ratio of testosterone to estrogen at the age of 56 days. However, there was a delay in the formation of sperm at the age of 56 days.
Keyword: male rats, phytoestrogen, prepuberty, reproduction development, tempe extract.

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.
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