Judul: Uji Toksisitas Ekstrak Etanol Rimpang Temu Putih terhadap Larva Udang dan Embrio Ikan Zebra
Abstrak: Curcuma zedoaria, known as temu putih, is commonly used as traditional medicine in Indonesia. The toxicity of this herb needs to be studied to improve its application. This research aims to evaluate the toxicity of the crude ethanol extract of temu putih rhizome against brine shrimp (Artemia salina) larvae and zebrafish (Danio rerio) embryos and to analyze the suspected active compounds contained in the extract. The crude ethanol extract showed 50% lethal concentration value (LC50) at 588 ppm against brine shrimp larvae and 215 ppm against zebrafish embryos. In zebrafish embryos, exposure of the crude ethanol extract has caused major malformation in development of head, namely brain and eyes organs. Based on the gas chromatography-mass spectrometry analysis, the suspected active compound that play a role in the toxicity are epicurzerenone, curzerene, and curzerenone, which 2,4,6-trimethylacetophenone as the predominant compound.
Keyword: Bogor Agricultural University (IPB), LC50, Danio rerio, Curcuma zedoaria, Artemia salina

Judul: Perkembangan Embrio Ikan Zebra (Danio Rerio) Setelah Paparan Ekstrak Etanol Temu Lawak (Curcuma Xanthorrhiza) Dan Temu Putih (Curcuma Zedoaria).
Abstrak: Temu lawak dan temu putih merupakan obat tradisional yang telah digunakan secara turun-temurun. Kedua tanaman ini telah dilaporkan bersifat toksik pada embrio ikan zebra. Penelitian ini bertujuan untuk mempelajari perkembangan embrio ikan zebra setelah paparan ekstrak temu lawak, temu putih, dan campurannya. Nilai LC50 ekstrak etanol temu lawak, temu putih, dan campurannya berturut-turut adalah 16.9, 112.1, dan 82.9 ppm. Ekstrak temu lawak menyebabkan penghambatan proses menetas pada embrio ikan zebra, sebaliknya ekstrak temu putih tidak menunjukkan efek penghambatan tersebut. Malformasi mayor yang terjadi pada embrio ikan zebra akibat paparan ekstrak temu lawak adalah edema perikardium, koagulasi darah, notokorda, dan edema kantong kuning telur; akibat paparan temu putih adalah edema perikardium dan koagulasi darah; serta akibat paparan campuran keduanya adalah edema perikardium, koagulasi darah, dan sirkulasi darah. Ekstrak temu putih memiliki sifat antagonis terhadap ekstrak temu lawak, yaitu mampu menghilangkan efek penghambatan proses menetas serta menurunkan kelainan pada notokorda dan kantong kuning telur.
Keyword: abnormalitas, embrio ikan zebra, LC50, temu lawak, temu putih

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.
Keyword: