Judul: Status of Microb and Somatic Cell Count of Quaternary Milk  from Cijeruk Farm, Bogor and Pondok Ranggon, East Jakarta
Abstrak: Peternakan sapi perah di Kecamatan Cijeruk termasuk salah satu daerah di dataran tinggi dengan jumlah pasokan susu terbanyak di Bogor, sedangkan salah satu peternakan di dataran rendah dengan produksi susu tertinggi berada di Pondok Ranggon, DKI Jakarta. Perbedaan ketinggian lokasi serta kondisi lingkungan di sekitar peternakan dapat mempengaruhi produktivitas sapi perah. Penelitian ini bertujuan mengetahui perbedaan kualitas mikrob dan jumlah sel somatik susu dari peternakan di dataran rendah dan dataran tinggi. Variabel yang diamati dalam penelitian ini adalah Angka Lempeng Total (ALT) mikrob, jumlah Staphylococcus aureus, dan jumlah sel somatik (JSS). Pengujian mikrob dilakukan dengan metode hitung cawan dan penghutungan JSS menggunakan metode Breed. Data yang diperoleh dianalisis secara statistik dengan uji Mann-Whitney U dan Chi-square. Hasil penelitian ini menunjukkan ALT mikrob, jumlah S. aureus, dan JSS pada peternakan Pondok Ranggon lebih tinggi dibandingkan dengan peternakan Cijeruk. Rata-rata ALT mikrob, jumlah S. aureus, dan JSS pada peternakan Cijeruk berturut turut adalah 1,6 x 104 ± 1,5 x 104 koloni/ml, 1,3 x 103 ± 4,2 x 103 koloni/ml, dan 1.795.000,0 ± 1.838.791,4 sel/ml. Rata-rata ALT mikrob, jumlah S. aureus, dan JSS pada peternakan Pondok Ranggon berturut-turut adalah 3,5 x 105 ± 1,0 6 x 10 koloni/ml, 1,7 x 105 ± 6,3 x 104 koloni/ml dan 3.032.222,2 ± 4.348.654,1 sel/ml. Penelitian ini menunjukkan terdapat hubungan antara ketinggian wilayah peternakan dengan S. aureus (P< 0,05). Status mikrob dan jumlah sel somatik dipengaruhi oleh perbedaan daerah peternakan dengan pola pemeliharaan dan keadaan lingkungan yang berbeda., The difference in height of the rearing area and the different conditions of the two areas can affect the productivity of dairy cattle. This research aimed to determine differences in microbial quality and the somatic cell count from farms in the lowlands and highlands. The variables observed in this study were the microbial total plate count (TPC), the number of Staphylococcus aureus, and somatic cell count (SCC). Microbial testing was carried out using the plate count method and the somatic cells count used the Breed method. The data obtained was analyzed statistically using Mann-Whitney U and chi-square. The results of this study showed that TPC, S. aureus, and SCC of Milk from Pondok Ranggon were higher than in Cijeruk. The average of TPC, S. aureus, and SCC in Cijeruk were 1,6 x 104 ± 1,5 x 104 colonies/ml, 1,3 x 103 ± 4,2 x 103 colonies/ ml, and 1.795.000,0 ± 1.838.791,4 cells/ml respectively. The average of TPC, S. aureus, and SCC on the Pondok Ranggon were 3,5 x 105 ± 1,06 x 106 colonies/ml, 1,7 x 105 ± 6,3 x 104 colonies/ml and 3.032.222,2 ± 4.348.654,1 cells/ml respectively. This research showed that the height of the rearing area have relationship with S. aureus (P< 0,05). Microbial status and the somatic cell count are influenced by differences in livestock areas with different maintenance patterns and environmental conditions.
Keyword: susu kuartir, jumlah sel somatik, angka lempeng total, Staphylococcus  aureus, milk quarternary, somatic cell count, total plate count

Judul: Microbial Status of Milk from the Fore and Rear Udder of Dairy Cows
Abstrak: Penelitian ini bertujuan menganalisis kualitas mikrob susu yang berasal dari bagian depan dan belakang ambing sapi perah dari peternakan Cijeruk, Bogor dan peternakan Pondok Ranggon, Jakarta Timur. Sampel susu berasal dari bagian depan dan belakang ambing dari 24 ekor sapi perah dalam masa laktasi normal. Total sampel yang digunakan dalam penelitian ini sebanyak 48 sampel. Kualitas mikrob susu yang diamati, antara lain Total Plate Count (TPC), jumlah Enterobacteriaceae, dan jumlah S. aureus. Penghitungan jumlah mikrob menggunakan metode hitungan cawan. Hasil penelitian menunjukkan rata-rata TPC susu dari ambing depan sebesar 1,6x105 ± 5,1x105 CFU/mL dan ambing belakang sebesar 2,0x105 ± 9,2x105 CFU/mL, jumlah Enterobacteriaceae susu dari ambing depan sebesar 5,8x102 ± 2,1 x 103 CFU/mL dan ambing belakang sebesar 1,5x102 ± 4x102 CFU/mL dan jumlah S. aureus susu dari ambing depan sebesar 7,5x104 ± 2,2x104 CFU/mL dan ambing belakang sebesar 1,0x105 ± 1,0x105 CFU/ml. Penelitian ini menunjukkan kualitas mikrob susu dari ambing bagian belakang lebih tinggi dibandingkan ambing bagian depan. TPC dan jumlah Enterobacteriaceae susu yang berasal dari ambing depan dan belakang sapi perah tidak berbeda nyata (P>0,05), sementara jumlah S. aureus susu berbeda nyata (P<0,05). Jumlah S. aureus susu dari ambing belakang lebih tinggi dibandingkan dengan ambing depan. Perbedaan yang nyata dari cemaran S. aureus dalam susu terjadi pada sapi-sapi di daerah perkotaan (Pondok Ranggon), sementara pada sapi-sapi di daerah pedesaan (Cijeruk) tidak terlihat perbedaan yang nyata. The purpose of this study was to analyze the microbiological quality of milk based on the udder of dairy cows from Cijeruk, Bogor and Pondok Ranggon, East Jakarta. The sample were quarter milk from the front and rear udder of 24 dairy cows. The total number of samples in this study was 48. Parameters of this study were Total Plate Count (TPC), the number of Enterobacteriaceae, and the number of S. aureus. Microbiological examination using the total plate count method. The results showed, the average TPC of milk from the front and rear udder were 1,6x105 ± 5,1x105 CFU/mL and 2,0x105 ± 9,2x105 CFU/ml, the number of Enterobacteriaceae milk from the front udder were 5,8x102 ± 2,1x103 CFU/mL and the rear udder were 1,5x102 ± 4,0x102 CFU/ml, while the number of S. aureus milk were 7,5x104 ± 2,2x104 CFU/mL (the front udder), and 1,0x105 ± 1,0x105 (the rear udder). TPC and the number of Enterobacteriaceae milk from the front and rear udder of dairy cows did not difference significantly (P>0,05), while the number of S. aureus milk of the rear udder were higher than the front udder and were significantly different (P<0,05). The number of S. aureus in milk from the rear udder of dairy cows from Pondok Ranggon were significantly higher than the front udder, while in dairy cows from Cijeruk were no significant differences.
Keyword: Ambing, Enterobacteriaceae, S. aureus, susu segar, TPC

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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