Judul: Efektivitas Daun Sembukan (Paederia foetida) untuk Pencegahan Infeksi Bakteri Aeromonas hydrophila pada Ikan Nila (Oreochromis niloticus) melalui Pakan.
Abstrak: The purpose of this study was to determine the optimum dosage of Skunkvine leaves (Paederia foetida) to prevent Aeromonas hydrophila infection in tilapia (Oreochromis niloticus). This study consisted of five treatments, i.e negative control, positive control and different level of skunkive leave supplementation 0.8%, 1% and 1.2% in triplicate. Incorporation of skunkvine leave has done by coating method. Feed was given to satiation with a feeding frequency of three times a day. Fish were reared for 20 days, and challenge test using A. hydrophila has done on the 11th day after treatments for 10 days. The results of this study showed that survival levels before challenge test were unsignificant different (P<0.05), while survival levels after challenge test were significantly different (P<0.05) between positive control and skunkive treatments 0.8% (88.89%), 1% (74.08%) and 1.2% (74.08%). In concluse, the study showed that the addition skunkvine leave through feed is effective for prevention of A. hydrophila infection in tilapia with optimum dosage i.e 0.8%.
Keyword: Aeromonas hydrophila, Paederia foetida, tilapia

Judul: Prevention of Motile Aeromonad Septicemia in Tilapia  Larvae with Ambon Banana Stem Extract
Abstrak: Produksi ikan nila dapat ditingkatkan dengan mencegah kematian ikan pada fase larva. Fase larva pada ikan adalah fase yang rentan terserang penyakit, salah satunya Motile Aeromonad Septicaemia (MAS) yang diinfeksi oleh Aeromonas hydrophila. Salah satu cara untuk mencegah MAS adalah dengan perendaman menggunakan ekstrak seduh batang pisang ambon. Penelitian ini bertujuan untuk menentukan dosis optimum perendaman larva ikan nila dengan ekstrak seduh batang pisang ambon untuk pencegahan infeksi A. hydrophila. Bahan uji yang digunakan adalah larva ikan nila, batang pisang ambon dan bakteri A. hydrophila. Penelitian terdiri dari perlakuan K+ (tanpa perendaman dengan ekstrak seduh batang pisang ambon dan diuji tantang dengan A. hydrophila), dosis perendaman ekstrak seduh batang pisang ambon (0,1% (v/v), 0,25%(v/v) dan 0,5%(v/v)) selama 30 menit. Pemeliharaan larva dilakukan selama 14 hari dan diuji tantang pada hari ke-8 dengan kepadatanbakteri 104 CFU/mL (LC50) sebanyak 1 mL/60 ekor dan direndam selama satu jam kemudian dipindahkan ke wadah pemeliharaan. Perendaman dengan ekstrak seduh batang pisang ambon dapat meningkatkan sintasan pada larva ikan nila yang diuji tantang dengan A. hydrophila. Dosis perendaman ekstrak batang pisang ambon pada larva ikan nila adalah 0,25% dan 0,5% dengan sintasan sebesar 90,01±1,81% dan nilai RPS sebesar 84,54% yang didukung dengan parameter respon imun berupa aktivitas lisozim. Kata kunci: Aeromonas hydrophila, batang pisang, ikan nila, sintasan, Tilapia production can be increased by preventing fish mortality in the larval stage. The larval phase in fish is a phase that is susceptible to disease, one of which is Motile Aeromonad Septicaemia (MAS) which is infected by Aeromonas hydrophila. One way to prevent MAS is by soaking using the extract of the brewed banana stem of Ambon. This study aims to determine the optimum dose of immersion of tilapia larvae with ambon banana stem extract to prevent A. hydrophila infection. The test materials used were tilapia larvae, Ambon banana stem and A. hydrophila bacteria. The study consisted of K + treatment (without immersion in the extract of ambon banana stem and challenged with A. hydrophila), immersion dose of ambon banana stem extract (0.1%(v/v), 0.25%(v/v) and 0.5%(v/v)) for 30 minutes. Larva rearing was carried out for 14 days and tested on the 8th day with a bacterial density of 104 CFU / mL (LC50) of 1 mL / 60 and soaked for one hour then transferred to a rearing container. Soaking with the extract of ambon banana stem brewed can increase survival in tilapia larvae that were challenged with A. hydrophila. The immersion dose for Ambon banana stem extract in tilapia larvae is 0.25% and 0.5% with a survival rate of 90.01 ± 1.81% and an RPS value of 84.54% which is supported by immune response parameters in the form of lysozyme activity. Key words: Aeromonas hydrophila, banana stem, survival rate, tilapia
Keyword: Aeromonas hydrophila, Banana stem, Survival rate, tilapia

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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