Judul: Identification and Total of Lactic Acid Fermentative Bacteria in Primate Feces
Abstrak: Bakteri asam laktat (BAL) bermanfaat bagi kesehatan, terutama peranannya sebagai probiotik dan antimikroba dalam pengobatan penyakit saluran pencernaan pada primata. Penelitian ini bertujuan untuk mengidentifikasi serta menghitung total koloni bakteri asam laktat pada feses lima jenis primata yaitu orang utan, owaungko hitam, owa ungko coklat, siamang, dan lutung yang dikoleksi dari Kebun Binatang Bukittinggi. Sampel dilakukan pengenceran 10-1 hingga ke 10-7 dandiinokulasikan ke dalam media selektif MRSA (de Man Rogosa Sharpe Agar) dengan metode pour plate. Koloni bakteri asam laktat yang tumbuh pada media diamati dan dihitung total koloninya. Koloni terpilih diisolasi untuk selanjutnya diidentifikasi menggunakan beberapa uji biokimia yaitu uji katalase, uji oksidase, uji Sulfide Indol Motility, uji Methyl Red-Voges Proskauer, dan uji fermentasi karbohidrat. Penelitian berhasil mengisolasi bakteri dari genus Lactobacillus, Leuconostoc, dan Weissella. Hasil penelitian menunjukkan orang utan menghasilkan total bakteri asam laktat tertinggi yaitu sebesar 3,1 x 108 CFU/ml., Lactic acid bacteria (LAB) are beneficial for health, especially their role as probiotics and antimicrobials in the treatment of digestive tract diseases in primates. This research aims to identify and count the total colonies of lactic acid bacteria in the feces of five primate species, namely orangutans, black gibbons, brown gibbons, siamang, and langurs collected from the Bukittinggi Zoo. Samples were diluted 10- 1 to 10-7 and inoculated into MRSA (de Man Rogosa Sharpe Agar) selective media using the pour plate method. Colonies of lactic acid bacteria growing on the media were observed and the total colonies were counted. Selected colonies were isolated for further identification using several biochemical tests, namely catalase test, oxidase test, Sulfide Indole Motility test, Methyl Red-Voges Proskauer test, and the carbohydrate fermentation test. The results of the research succeeded in isolating lactic acid bacteria from the genera Lactobacillus, Leuconostoc, and Weissella. Orangutans produced the highest total lactic acid bacteria, which was 3.1 x 108 CFU/ml.
Keyword: lactic acid bacteria, primates, total plate count

Judul: Identification of Lactic Acid Fermentative Bacteria from the Faeces of Proboscis Monkey (Nasalis larvatus), Kalimantan Endemic Primates
Abstrak: Bakteri Asam Laktat (BAL) adalah golongan bakteri yang memiliki peran dalam pencernaan dengan sifat tidak toksik bagi inangnya dan mampu menghasilkan beberapa senyawa yang dapat mengeliminasi bakteri patogen. Penelitian ini bertujuan mengidentifikasi jenis bakteri asam laktat yang terdapat pada feses bekantan. Sampel feses yang diinokulasikan pada media MRSA (de Mann Rogosa Sharpe Agar), Pengujian biokimia dengan uji oksidase, Triple Sugar Iron Agar (TSIA), uji urease, uji IMViC. Uji IMVIC sendiri terdiri dari beberapa uji yaitu uji Sulfide Indol Motility (SIM), uji Methyl Red-Voges Proskauer, dan uji Simmon’s Citrate, serta pengujian fermentasi karbohidrat yang terdiri dari glukosa, laktosa, sukrosa, maltosa, manitol, dan dulsitol. Berdasarkan hasil uji yang dilakukan didapatkan jenis bakteri Lactobacillus buchneri, Lactobacillus brevis, dan Lactobacillus plantarum, Lactic Acid Bacteria (LAB) are a group of bacteria that have a role in digestion with non-toxic properties to their host and can produce several compounds that can eliminate pathogenic bacteria. This study aims to identify the types of lactic acid bacteria found in proboscis monkey feces. The method used was a simple test with fecal samples inoculated on MRSA media (de Mann Rogosa Sharpe Agar), biochemical testing with oxidase test, Triple Sugar Iron Agar (TSIA), urease test, IMViC test. The IMVIC test itself consists of several tests, namely the Sulfide Indole Motility (SIM) test, Proskauer's Methyl Red-Voges test, Simmon's Citrate test, and carbohydrate fermentation testing consisting of glucose, lactose, sucrose, maltose, mannitol, and Dulcitol. Based on the results of the tests carried out, it was found that the types of bacteria Lactobacillus buchneri, Lactobacillus brevis, and Lactobacillus plantarum.
Keyword: Lactic acid bacteria, monkey feces, primates

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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