Judul: Hubungan Gaya Hidup dan Pengetahuan Gizi terhadap Kebiasaan Makan Remaja di Pedesaan dan Perkotaan
Abstrak: The objective of this research was to study correlation between life styles and nutrition knowledge with eating habit of rural and urban adolescent. Research design was cross sectional study.Samples were selected from adolescent of Senior High School of 10th grader at SMA Negeri 109 Jakarta Selatan and SMK Giri Taruna Jasinga, Kabupaten Bogor. Sampling was done using Simple Random Sampling. The sample consisted of 110 students. The results that the higher the smoking habit the lower the habit of buying street or junk food, the higher internet usage the higher the water consumption, and the higher the nutrition knowledge the lower the eating frequency and the water consumption.
Keyword: eating habit, nutrition knowledge, internet usage, smoking habit, adolescent

Judul: Hubungan antara Kebiasaan Makan dengan Status Gizi pada Remaja di Perkotaan dan Perdesaan
Abstrak: Double burden of nutritional problems are not only faced by urban societies but also rural societies. This study aimed to analyze association of eating habits, physical activities and nutritional status of adolescence in urban and rural areas. The study used cross sectional design involved 102 adolescences. There were significant differences (p<0.05) between subject in urban and rural in term of age, daily pocket money, parents’ educational background, family income, family size, frequency consumption of noodles, chicken, tofu, soybean, carrot, banana, orange, physical activity of school day. There was no significant difference in frequency of a having meal and habit on buying snacks. There was significant correlation between ages, genders, parents’ educational level, family size, family income and nutritional status (TB/U), as well as gender and nutritional status (IMT/U). However, there was no significant correlation between eating habits, physical activities, energy and nutrients adequacy levels and nutritional status (p>0.05).
Keyword: nutritional status, adolescence, food consumption, eating habits, physical activities

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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