Judul: Resistance of Staphylococcus sp. Against Antibiotics from Animal Clinics in Depok City
Abstrak: Staphylococcus sp. is an opportunistic bacteria that is often found in animals and humans. Various studies have shown Staphylococcus sp. can become resistant to at least one antibiotic. This study aims to identify the Staphylococcus sp. isolated from hospitalized cats at the veterinary clinic in Depok City and understand Staphylococcus sp. resistance against amoxicillin, gentamicin, cefotaxime, doxycycline, and enrofloxacin. Antibiotic sensitivity test was conducted by Kirby-Bauer Disk Diffusion method. The results showed that 9 isolates (45%) were Staphylococcus sp. consisting of 7 isolates of S. aureus and 2 isolates of S. epidermidis. The test results showed the resistance of S. aureus isolates to amoxicillin (1 isolate), cefotaxime (7 isolates), doxycycline (1 isolate), enrofloxacin (1 isolate). S. epidermidis isolates were resistant to amoxicillin (1 isolate), cefotaxime (1 isolate), doxycycline (1 isolate). Antibiotics that can still be used for S. aureus infection are enrofloxacin, gentamicin, doxycycline, and amoxicillin, while those from S. epidermidis used gentamicin and enrofloxacin., Staphylococcus sp. merupakan bakteri oportunistik yang sering ditemukan pada hewan dan manusia. Berbagai penelitian menunjukkan isolat Staphylococcus sp. dapat menjadi resistan terhadap setidaknya satu jenis antibiotik. Penelitian ini bertujuan mengidentifikasi bakteri Staphylococcus sp. yang diisolasi dari kucing rawat inap di klinik hewan Kota Depok dan mengetahui gambaran resistansi Staphylococcus sp. terhadap antibiotik amoksisilin, gentamisin, sefotaksim, doksisiklin, dan enrofloksasin. Pengujian kepekaan antibiotik menggunakan metode Disk Diffusion Kirby-Bauer. Hasil penelitian menunjukkan 9 isolat (45%) merupakan Staphylococcus sp. yang terdiri dari 7 isolat S. aureus dan 2 isolat S. epidermidis. Hasil uji menunjukkan resistansi isolat S. aureus terhadap amoksisilin (1 isolat), sefotaksim (7 isolat), doksisiklin (1 isolat), enrofloksasin (1 isolat). Isolat S. epidermidis resistan terhadap amoksisilin (1 isolat), sefotaksim (1 isolat), doksisiklin (1 isolat). Antibiotik yang masih dapat digunakan untuk infeksi S. aureus adalah enrofloksasin, gentamisin, doksisiklin, dan amoksisilin, sedangkan infeksi S. epidermidis dapat diobati dengan gentamisin dan enrofloksasin.
Keyword: kucing/cats, antibiotik, antibiotics, Staphylococcus sp., Staphylococcus sp.

Judul: Resistansi Escherichia coli yang Diisolasi dari Kucing di Klinik Hewan Kota Depok Terhadap Antibiotik
Abstrak: Kejadian resistansi antibiotik pada Escherichia coli pada hewan kesayangan sangat erat kaitannya dengan penggunaan antibiotik yang tidak tepat dalam waktu panjang dan tidak terkontrol. Penelitian ini bertujuan mengetahui gambaran resistansi E. coli yang diisolasi dari kucing rawat inap di klinik hewan Kota Depok terhadap antibiotik amoksisilin, gentamisin, sefotaksim, enrofloksasin, dan doksisiklin. Uji kepekaan antibiotik pada penelitian ini menggunakan metode Disk Diffusion Kirby-Bauer. Didapati sebanyak 12 isolat merupakan Escherichia coli. Hasil uji menunjukkan sampel resistan terhadap doksisiklin (sembilan isolat), amoksisilin (lima isolat), dan sefotaksim (lima isolat). Hasil intermediet ditunjukkan oleh amoksisilin dan sefotaksim, 16.7% resistan terhadap gentamisin, dan 8.3% resistan terhadap enrofloksasin. Escherichia coli pada penelitian ini masih cenderung sensitif terhadap gentamisin dan enrofloksasin., Antibiotic resistance in Escherichia coli in pets is closely linked to the long term and uncontrolled use of antibiotics. The study aims to determine the resistance of isolated E. coli cats in the City Depok veterinary clinic to the antibiotics amoxicillin, gentamicin, cefotaxime, enrofloxacin, and doxycycline. Antibiotic sensitivity test in this study using the Kirby-Bauer Disk Diffusion method. Twelve isolates were found to be Escherichia coli. The test results showed samples resistant to doxycycline (nine isolates), amoxicillin (five isolates), and cefotaxime (five isolates). Intermediate results were shown by amoxicillin and cefotaxime, with 16.7% resistance to gentamicin, and 8.3% to enrofloxacin. Escherichia coli in this study still tends to be sensitive to gentamicin and enrofloxacin.
Keyword: antibiotics, antibiotic resistance, escherichia coli

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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