Judul: Stek Pucuk Merawan (Hopea cernua Teijsm. & Binn.) dengan Perlakuan Media Tumbuh dan Hormon
Abstrak: Merawan (Hopea cernua Teijsm. & Binn.) is one of species that being tested in Center for Conservation and Rehabilitation Research and Development (CCRRD) Gunung Batu. This species brought from its natural source in Lampung to CCRRD for the advanced research. The purpose is to acquire the best treatments that can be used for species propagation effort. This research shown that sand media with 5% husk charcoal has a very real effect for survival percentage, shooting percentage; and has a real effect for rooting percentage, root length and number of roots. Rootone-F hormone has a real effect for the survival percentage and shooting percentage. The highest result for survival percentage were seen in sand media with husk charcoal by 91.38% and in Rootone-F by 86.00%. The highest results for shooting percentage were seen in sand media with husk charcoal by 77.18% and 71.43% for Rootone-F hormone. The highest result for rooting percentage, root length and number of roots were seen in sand media with husk charcoal by 18.57%, 214.25 cm, and 64 roots.
Keyword: shoot cuttings, hormone, Hopea cernua, growth media

Judul: Pengaruh Umur Pohon Induk dan Jenis Media terhadap Keberhasilan Stek Pucuk Bintaro (Cerbera manghas L.)
Abstrak: Bintaro (Cerbera manghas L.) is one of tree species that grows naturally on coastal areas which it seeds may produce a high quality of biofuel. Bintaro propagation generatively may reduce the seeds availability as bio fuel producer. Therefore, the vegetative propagation is one of the technique that may solve the problem. The purpose of this research were to examine the effect of parent tree’s age (6 month old and 10 years old) and the media types (zeolite, charcoal chaff, mixed of cocopeat and rice husk (2:1)) on the success of bintaro cutting sprout. Parameters observed are percentage of germinate, percentage of roots, length of primary root, and dry weight of roots. The difference of parent tree age influence significantly the cutting success of bintaro sprout. The parent tree within 6 month old gave the highest result toward all parameters observed rather than the parent tree of 10 years old. The mixed media of cocopeat and rice husk (2:1) and also the charcoal chaff gave higher respond toward the amount of primary roots and dry weight of roots compared to the zeolite media type.
Keyword: shoot cutting, media types, biofue, bintaro, age of the parent tree’s

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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