Judul: Keanekaragaman jenis tumbuhan dan struktur tegakan pada kawasan pesisir Cagar Alam Kepulauan Krakatau, Provinsi Lampung
Abstrak: Vegetasi pada kawasan pesisir memiliki ciri-ciri yang berbeda dan khas dibandingkan dengan vegetasi pada ekosistem hutan lainnya, salah satunya pada kawasan pesisir Cagar Alam Kepulauan Krakatau. Letusan pada tahun 1883 diduga menyebabkan pemusnahan hutan yang sempurna di kawasan Kepulauan Krakatau sehingga vegetasi yang ada saat ini merupakan vegetasi baru. Penelitian ini bertujuan untuk menganalisis komposisi jenis dan struktur tegakan yang diharapkan dapat memberikan informasi mengenai tingkat keanekaragaman hayati vegetasi kawasan pesisir guna pengelolaan dan pelestarian di lokasi tersebut. Penentuan lokasi pengamatan ditentukan secara purposive sampling berdasarkan keterwakilan tegakan di setiap pulau, yaitu Sertung, Panjang, Rakata Besar, dan Anak Krakatau. Pada setiap lokasi dibuat satu petak contoh berukuran 100 m x 100 m. Berdasarkan penelitian yang dilakukan ditemukan sebanyak 105 spesies tumbuhan dari 47 famili. Jenis-jenis yang mendominasi pada umumnya merupakan jenis pionir, seperti Ipomoea pes-caprae dan Casuarina equisetifolia. Keanekaragaman jenis di setiap pulau bervariasi mulai dari rendah hingga sedang. Struktur horizontal membentuk kurva J terbalik dan struktur vertikal tegakan terdiri atas empat strata, yaitu B, C, D, dan E.
Keyword: coastal, diversity, Krakatau, nature reserve, stand structure

Judul: Colonization of Coral Communities in the Krakatau Strict Marine Nature Reserve, and Management Implications
Abstrak: The eruption and near-total destruction of the volcano Krakatau on the 26 – 28 August 1883 was completely exterminating all ecosystems life in the Krakatau Islands and surrounding area (i.e. Sebesi, Sebuku and Legundi). After three months of minor activity, that catastrophic eruption destroyed over two thirds of Krakatau, only a fraction of Rakata remaining. The islands diversity is geomorphologically dynamic, and the effects of physical changes on the biota, and on the rate of successional turnover, are considerable interesting. In addition, the islands discrete, definable, tropical biota provides a rare opportunity for ecological studies, particularly of communities interactions that has develop in this area. The purposes of this research were to determine the condition and describe the colonization development of coral communities in the Krakatau Islands after total destruction, including disturbances from natural environment. Benefit was to provide amount recent information of composition, distribution, and structure of coral communities in the Krakatau Islands. Also for explain the extent of coral damage, and the implications for management of coral reefs in the Krakatau Strict Nature Reserve. This study showed that succession or development of coral communities (i.e. colonization) that found in Anak Krakatau indicated earlier stage of colonization. Where have different with coral communities that found in Rakata and Panjang. The diversification of coral communities on both islands, showed that opportunistic and pioneer species (i.e. Pocillopora and Seriatopora) that generally found in Anak Krakatau has been replaced. Lifeform of coral communities found varied between sites, where sub-massive is dominated lifeform that found in Anak Krakatau, but massive and branching lifeform are more dominant in Rakata and Panjang. There are indication of dominance may already take place through competitive exclusion in coral communities. Three community types were distinguished based on characteristics for each sites, as follows: communities of wave-exposed habitats, communities of semi- exposed to sheltered habitats, and communities of sheltered habitats. The extent of coral damage that found in Krakatau based on CMI value is low, in average, but high value found in the community of wave-exposed habitat. While, following CDI criteria, the extent of coral damage covered all six sites. This suggests that of the all transects were "hot spots'' that required management action. Although Krakatau Strict Marine Nature Reserve has been declared part of Ujung Kulon National Park in 1983, it is not managed as such because it falls under a different province. Furthermore, it has been managed subsequently by BKSDA Lampung since 1990.
Keyword: colonization, coral communities, Krakatau, management, succession

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