Judul: Keragaman Fenotipe Rumput Laut Gracilaria spp. yang Dibudidayakan di Tambak Desa Lengensari, Subang
Abstrak: Terdapat kendala produksi bagi industri pengolahan rumput laut yang ada di Indonesia akibat kualitas Gracilaria yang tidak konsisten. Kualitas Gracilaria ditentukan, salah satunya oleh kualitas bibit, sementara itu terdapat beragam kualitas bibit yang dipengaruhi oleh keragaman fenotipe. Penelitian ini bertujuan mengumpulkan informasi mengenai keragaman fenotipe rumput laut pada tambak budidaya Gracilaria spp. di Desa Langensari, Kecamatan Blanakan, Subang, Jawa Barat sebagai data dasar pendugaan produksi dan kriteria mutu rumput laut. Kaitan antara keragaman fenotipe dan kondisi lingkungan perairan tambak di mana rumput laut dibudidayakan juga dianalisis. Sampel rumput laut Gracilaria spp. dikoleksi dari 12 lokasi pada empat tambak, yaitu di inlet, middle, dan outlet. Empat petak tambak yang dibedakan berdasarkan tingkat salinitas, yakni 4,0-4,4; 4,1-5,8; 6,5-7,4; dan 11,7-11,9 ppt. Sampel rumput laut selanjutnya diamati warnanya, ditimbang bobotnya, dan diukur diameter talus, panjang talus, internode talus, dan dihitung percabangannya.
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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