Judul: Literature Study of Carbohydrase and Phytase Enzymes as Antibiotic Growth Promoter Substitutions in Broiler Chickens
Abstrak: Penggunaan Antibiotic Growth Promoter (AGP) pada pakan cenderung memberikan dampak negatif bagi kesehatan masyarakat. Berdasarkan hal tersebut, beberapa enzim sudah diteliti sebagai pengganti AGP untuk memberikan efek yang sama tanpa memberikan efek negatif. Studi ini bertujuan mengetahui efektivitas enzim karbohidrase dan fitase yang dapat dijadikan substitusi AGP pada ayam broiler. Metode yang digunakan pada penelitian menggunakan situs pencarian karya ilmiah seperti “Google Scholar” dan “ScienceDirect”. Data yang diperoleh dari metode penelusuran tersebut, masing-masing sebanyak tujuh enzim karbohidrase dan fitase. Berdasarkan studi pustaka yang dilakukan, efek yang diberikan enzim karbohidrase diantaranya meningkatkan performa dan menurunkan viskositas pencernaan serta memperbaiki penampilan ayam broiler berumur muda. Selain itu, enzim fitase menimbulkan adanya peningkatan performa dengan pemanfaatan fosfor yang baik pada ayam broiler., The use of Antibiotic Growth Promoter (AGP) in feed tends to have a negative impact on public health. Based on this, several enzymes have been studied as substitutes for AGP to give the same effect without having negative effects. This study aims to determine the effectiveness of carbohydrase and phytase enzymes which can be used as AGP substitution in broiler chickens. The method used in this research is using scientific paper search sites such as "Google Scholar" and "ScienceDirect". The data obtained from the tracing method consisted of seven carbohydrase and phytase enzymes respectively. Based on the literature study conducted, the effects of carbohydrase enzymes include increasing performance and reducing digestive viscosity as well as improving the appearance of young broilers. In addition, phytase enzymes lead to an increase in performance with good phosphorus utilization in broiler chickens.
Keyword: AGP, ayam broiler, fitase, karbohidrase, performa, AGP, broiler chickens, carbohydrase, performance, phytase

Judul: In Silico Study: The Potential of Kaffir lime leaves  (Citrus hystrix) as an Alternative to Antibiotic Growth Promoter (AGP) in Broiler  Chickens
Abstrak: Ayam broiler merupakan ternak yang rentan terinfeksi mikroorganisme pa togen, sehingga banyak peternak menggunakan Antibiotic Growth Promoter (AGP). AGP merupakan imbuhan pakan yang diberikan untuk memacu pertum buhan dan memperbaiki saluran pencernaan, namun kini sudah dilarang penggunaannya. Pelarangan AGP menyebabkan peralihan penggunaan imbuhan pakan seperti imbuhan pakan fitogenik. Daun jeruk purut (Citrus hystrix) mem iliki senyawa aktif metabolit sekunder sehingga berpotensi untuk dijadikan im buhan pakan fitogenik. Penelitian ini bertujuan menganalisis potensi senyawa ak tif daun jeruk purut dengan melihat berbagai aktivitas biologi dan kemampuan dalam menghambat bakteri E. coli dan S. aureus menggunakan metode in silico. In silico merupakan metode komputasi yang digunakan untuk memprediksi kiner ja senyawa aktif suatu bahan. Senyawa aktif yang diperoleh berasal dari jurnal terindeks scopus, kemudian dilakukan pencarian kode SMILES, nilai probable activity (Pa), dan prediksi interaksi antara senyawa aktif dengan protein bakteri E.coli dan S.aureus. Hasil yang didapatkan yaitu 143 senyawa aktif memiliki kode SMILES dan 96 dari 143 senyawa aktif memiliki nilai Pa 0,300 pada ak tivitas antibakteri, antioksidan, penghambat glikosiltransferase peptidoglikan, antiinfeksi, imunomodulator, dan antiinflamasi sehingga berpotensi sebagai alter natif AGP. Daun jeruk purut juga mampu menghambat bakteri E. coli dan S. aureus secara in silico., Broiler chickens are livestock that are susceptible to infection with pathogenic microorganisms, so many farmers use Antibiotic Growth Promoter (AGP). AGP is a feed additive given to stimulate growth and improve the digestive tract, but its use is now prohibited. The prohibition of AGP has led to a shift in the use of feed additives such as phytogenic feed additives. Kaffir lime leaves (Citrus hystrix) have active secondary metabolite compounds that have the potential to be used as phytogenic feed additives. This study aims to analyzing the potential of the active compounds and the activity kaffir lime leaves by looking at various biological activities and abilited E. coli and S. aureus bacteria using the in silico method. In silico is a computational method used to predict the performance of the active compound of a material. The active compounds were obtained from scopus indexed journals, then searched for the SMILES code, probable activity (Pa) values, and predicted interactions between the active compounds and the proteins of E.coli and S.aureus bacteria. The results obtained were 143 active compounds had SMILES code and 96 of 143 active compounds had a Pa 0,300 value for antibacterial, antioxidant, peptidoglycan glycosyltransferase inhibitor, anti-infective, immunomodulatory, and anti-inflammatory so that it has the potential to be used as an alternative to AGP. Kaffir lime leaves are also able to inhibit E. coli and S. aureus bacteria in silico.
Keyword: antibiotik growth promoter, in silico

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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