Judul: Produksi serasah daun mangrove dan keragaman makrobentos infauna di Perhutani Blanakan, Subang, Jawa Barat
Abstrak: Macrobentos infauna are the organisms that live in water base territory having oversize from 1 mm. The aim of this research was to know the rate of mangrove litter production and variance of macrobentos infauna in Perhutani Blanakan, Subang, West Java. This research was conducted from April to August 2008. Observation was conducted in Perhutani conservation area in Blanakan village. Quadnnt method was used to observe the variance of mangrove type. Single vegetation, tree and pole of Avice~inia marina, was explored during observation with each important value index (IVI) 300%. The average of leaf litter production which has been collected during 8 weeks is 90.29 gr/m2/2 weeks, while the average of mangrove leaf liner decomposition rate is 14.77%. The result of macrobentos infauna identification showed that there are about 77.67 individuals and 9.33 species every 1.93 liter in each restating with Tricoliapzilloiides from class Gastropoda as the dominant species.
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Judul: Kondisi Ekologi Makrobentos Pada Ekosistem Mangrove Dan Laut Desa Hanura, Kecamatan Padang Cermin, Propinsi Lampung.
Abstrak: Mangrove forest waters is an area that always affected by seawater tide; soft and always wet substrate with rich of organic materials. Mangrove forest water is very sensitive to anthropogenic disturbance. Thus, it will increase the amount of dissolve organic materials on surface, body, and bottom of sediment waters which will affect the physical-chemical condition of waters and macrobenthos community. The aim of this study is to describe ecological condition of macrobenthos in mangrove forest through diversity index, similarity index, and dominance index; describe physical-chemical parameter condition of interstisial waters on mangrove sediment and seawater; analyze organic materials inputs from mangrove leaves against macrobenthos abundance. This research was conducted in mangrove forest Hanura Village, Padang Cermin Sub-district, Lampung Province; from February-June 2012; using quadrate transect. Linier regression analysis shows that have different for physical-chemical parameter of interstisial water on mangrove sediment. Some macrobenthos have correlated with physical-chemical interestrial water on the mangrove sediment with value R2>50%. Coefficient determinan test indicate Anadara ferruginea (R2= 57,9%) and Chicoreus torrefactus (R2= 56,2%) have a real correlation with interestrial water in mangrove sediment and seawater. Coefficient correlation value Anadara ferruginea is (76,1%) and Chicoreus torrefactus is (75,0%) was shown linier relationship between macrobenthos and parameter physical-chemical waters.
Keyword: Macrobenthos community, mangrove and seawater, physical-chemical of water

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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