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: Performance analysis of Seaweed Gracilaria gigas at Sea and Ponds Cultivated System in West Nusa Tenggara Barat
Abstrak: Gracilaria gigas is a low level plants which does not have tree roots, stems and leaves of true, but in the form of thallus branching, and live in the sea with a depth that can still be reached by sunlight. G. gigas is one of seaweed species the from red algae type (Rhodophyceae) producsy agarofit, G. gigas have the high fiber and good for health. Thei research aims to analyze the performance of production, yield and quality of G. gigas seaweed cultivated in the sea and in the ponds. The cultivation of G. gigas in ponds was held in Sekotong, west Lombok by broadcast method in 1500 m2 planting area. While cultivation in the sea was held in Gerupuk Bay, Central Lombok by Long-line method the 1250 m2 planting area. Average productivity of G. gigas cultivated in the sea 12.72%, while in ponds 4.00%. the was seaweed yield cultivation in ponds reached 18, 53%, and in marine aquaculture reached 6.85%, while the quality that the gel strength of G. gigas cultured in ponds was 18.46%, and in the sea reached 7.54%. the yield and gel stregh were positively correlated with N waters and branching index. Cultivation of G. gigas in the sea with long-line method in order to produce a yield of 6.85%, 7.54% and gel strength, whereas in the stocking ponds with methods that produce a yield of 18.53%, 18.46% and gel strength. The quality of the cultivated seaweed in the ocean negatively correlated with salinity (0.87), while the cultivation in ponds negatively correlated with nitrate (0.85) and ammonia (0.95), and positively correlated with brightness (0.91) and phosphate (0.66). The branching index seaweed cultivated at the sea rods closely related salinity to approximately 87%. Seaweed cultivation in ponds shared negative associated between branching index and brightness (91%), and phosphate (66%), oxygen (62 %). Otherwise parameters associated negatively were branching index and ammonia (95%), o nitrate (85%).
Keyword: seaweed culture, Gracilaria gigas, branching index, seaweed quality, dan productivity

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