Judul: eragaan Fenotipe Rumput Laut Gracilaria spp. Budidaya Polikultur Pada Salinitas 6-18 g/kg Di Tambak Muara Gembong, Bekasi
Abstrak: The phenotype diversity of seaweed Gracilaria spp. and its relationship with water quality in the ex-shrimp ponds by polyculture system was evaluated to estimate the production potential and quality. Gracilaria spp. sample was collected from 16 sampling location with a salinity range of 6.2-17.6 g/kg. Phenotypical characters observed consisted of colour and thallus morphometrics such as length of main thallus, length of secondary thallus, length of tertiary thallus, internode of secondary thallus, internode of tertiary thallus and blade. The water quality parameters included water chemistry and physics. The results showed that Gracilaria spp. colour was light brown colour and brown at salinity higher than 7.4 g/kg. Salinity affects morphometric characters significantly (P<0.35) the length of main thallus, length of secondary thallus, and the internode of secondary thallus. The salinity influence conductivity, TDS, nitrate and phosphate concentrations which associated with the growth of seaweed. The length of main thallus, length of secondary thallus, and length of tertiary thallus decreased a long with salinity increased.
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Judul: Karakteristik Fenotipe Rumput Laut Gracilaria spp. yang Dibudidaya pada Salinitas Berbeda di Tambak Desa Pantai Sederhana, Muara Gembong
Abstrak: Gracilaria spp. is an euryhaline species which can live in the marine and brackish water. Developing Gracilaria spp. in Bekasi is very potential activity because this seaweed can be cultured in ex- shrimp ponds by polyculture systems. The objective of this research is to evaluate the performance of Gracilaria spp. based on phenotype morphological characteristics and its relationship with shrimp pond water quality. Sampling was done at 3 shrimp ponds with a salinity range of 13.7-19.2 g/kg. Phenotypical characteristics Gracilaria spp. consisted of colour and thallus morfometrics, while measurement of water quality consisted of physical and chemical characters of shrimp pond. The result shows that Gracilaria spp. generally have light brown colour and at salinity higher than 13.7 g/kg the number of secondary thalluses increased, the distance between internode tertiary thallus declined, and the number of ramification index increased. Salinity showed a positive correlation with remification index which was 0.571
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Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model