Judul: Isolasi dan Identifikasi Salmonella sp. pada Reptil.
Abstrak: Salmonella sp. is a zoonotic pathogenic agent. The incidence of salmonellosis can be spread by exotic pets. Microorganism infection in humans correlates with the popularity of exotic pets. This research aims to determine the presence of Salmonella on reptiles as a spreading factor through direct contact with humans. Cloacal skin swab of reptiles in one of petshops in Dramaga, Bogor were used as samples. This research was conducted through steps: isolation, presumptive test, and confirmation test. The result of this research showed that the prevalence of Salmonella on exotic animals especially reptiles in the mentioned pet shop is 7.5%. The positive results are mostly acquired from samples derived from snakes.
Keyword: isolation, identification, reptile, Salmonella sp., skin swab

Judul: Quantitative Analysis of Salmonella in Broiler Chiken Skin Sold in Bogor
Abstrak: One of the most popular meat that can be found in Indonesia is chicken meat. Chicken meat contains a lot of nutrients for human growth but can be dangerous if it is not perfectly cooked. Salmonella can cause disease in the digestive system. Salmonella bacteria lives in the digestive tract of humans and animals and can spread through food, especially meat, eggs, and milk (foodborne disease). Salmonella is known as a zoonotic agent, which means the disease can be transmitted from animals to humans. The aim of this study is to obtain the number of Salmonella in the chicken skin that is sold in wet-markets, supermarkets, traditional and modern chicken slaughterhouse in Bogor. This study was conducted by sampling chicken carcass from each place then followed by isolation and quantitative analysis of Salmonella from the breast and back regions of the chicken skin by the most probable number (MPN) method. The results showed that the number of Salmonella in the wet-market had the highest which is 586.8 MPN/g compared to other places and the back region of chicken had the highest number of Salmonella which is 315.1 MPN/g compared to the other parts of the skin.
Keyword: foodborne disease, most probable number (MPN), Salmonella, zoonosis

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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