Judul: Efektivitas Isolat Bakteri Rumen Kerbau Pencerna Serat dalam Fermentasi Hijauan Leguminosa dan Pemanfaatan Urea in vitro
Abstrak: Ruminants have ability to digest fiber component of feed due to the presence of cellulolitic bacteria in their rumen that secrete cellulase. Other bacteria have capability to digest protein by secreting protease and utilize non protein nitrogen. Fiber-digesting bacteria isolated from rumen of buffalo have not been confirmed in their ability to digest protein rich feed and utilize protein. This study aimed to evaluate the ability of fiber-digesting bacteria isolates in digesting leguminous herbage, degrading protein and utilizing non protein nitrogen. The first study was to compare the fermentability and coeficient digestibility of Calliandra callotyrsus, Leucaena leucocephala, Indigofera sp. and Gliricidia sepium by using bacteria in fresh rumen fluid and fiber-digesting bacteria isolates. The second study aimed to evaluate the ability of buffalo rumen bacterial isolates in the use of urea. Corn and cassava waste were used as carbohydrate sources with addition of urea as non protein nitrogen at level of 3%, 4,5%, and 6%. The first study showed that source of bacteria had no different effect on VFA concentration, and the coeficient digestibility of dry and organic matter of the herbage. The NH3 levels in the treatment of bacterial isolates was higher than that of fresh rumen fluid (P <0.05). The buffalo rumen bacterial isolates have the ability to degrade proteins and also showed that Indigofera sp., and Gliricidia sepium protein more susceptible to degradation than other legumes. The levels of NH3 in fermentaion media of feed added urea to 6% was in normal level. It was concluded that fiber-digesting rumen bacteria isolates were able to digest leguminous herbage and utilize the protein component of legume and capable of utilizing urea up to 6% in starchy feed.
Keyword: 

Judul: The Potency of Buffalo Rumen Bacteria Isolates in Fermenting Various Herbage and Their Viability during Storage
Abstrak: Cairan rumen merupakan inokulum yang mengandung mikroorganisme dalam jumlah besar. Populasi dan jenis mikroorganisme dapat bervariasi tergantung kepada jenis pakan, frekuensi pemberian pakan dan waktu pengambilannya. Isolat bakteri asal rumen kerbau juga inokulum yang merupakan sebagian dari mikroorganisme rumen dan diperkirakan dapat digunakan untuk evaluasi nilai nutrisi pakan. Isolat bakteri rumen tersebut mempunyai kemampuan dalam mencerna komponen serat pakan (Astuti, 2010; Gayatri 2010). Rifai (2010) melaporkan bahwa isolat bakteri rumen kerbau secara tunggal mampu mencerna bahan kering rumput gajah dan jerami padi hingga berturut-turut 48,8% dan 41,1%. Namun kemampuannya dalam mencerna komponen beberapa hijauan pakan belum diteliti lebih jauh. Di samping itu pemanfaatan secara luas dibatasi oleh bentuknya yang cair, anaerob dan sulit disimpan. Oleh karena itu tujuan lain dari penelitian ini adalah mengkaji kemampun isolat bakteri rumen dalam mencerna hijauan pakan dan mengkaji daya hidup isolat bakteri tersebut dalam media penyimpanan yang berbeda. Penelitian ini dilakukan in vitro dalam dua tahap. Tahap pertama membandingkan kemampuan campuran enam isolat bakteri asal rumen kerbau dengan bakteri rumen segar sebagai perlakuan dalam mencerna berbagai hijauan pakan menggunakan uji-t berpasangan. Hijauan pakan tersebut: Pennisetum purpureum, Panicum maximum, Paspalum notatum, Setaria splendida, dan Brachiaria humidicola. Umumnya serat kasar di atas 50% dan protein kasar di bawah 10%, kecuali pada Setaria splendida. Parameter yang diamati yaitu koefisien cerna bahan kering dan bahan organik (KCBK dan KCBO), NH3 dan VFA.Tahap kedua menggunakan Rancangan Acak Lengkap (RAL) pola faktorial (4 x 3) dengan faktor A adalah media penyimpan (tanah, arang, tepung tapioka dan UMB ) dan faktor B adalah waktu penyimpanan (0, 1, dan 2 minggu) dengan 3 ulangan. Data yang diperoleh dianalisis dengan sidik ragam (Analysis of Variance) Parameter yang diamati yaitu viability isolat bakteri selama penyimpanan.
Keyword: 

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
Keyword: