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: Keanekaragaman Fungi Mikoriza Arbuskula di Ekosistem Gunung Anak Krakatau, Lampung Selatan.
Abstrak: Anak Krakatau Mount ecosystem was resulted from natural succesion process. Vegetation diversity at the area was studied by several scientists, but simbiotic microbial such as mycorrhizae supporting the vegetation growth was not studied yet. Mycorrhizae is a mutual symbiosis between fungi (mykes) with a rooting (rhiza) plants. Mycorrhizae has spread widely, including in the new ecosystem where succession process occurs. This study aims to identify the genus of Arbuscular Mychorrhizal Fungi (AMF) diversity in the ecosystem of Anak Krakatau Mount, South Lampung. The method used was the extraction of spores using wet sieving and decanting method and centrifugation method, as well as coloring the roots to determine the percentage of colonization. Spore identification to genus level was done using a Melzer solution, while the roots staining was done using trypan blue as dye and PVLG as an adhesive. The results showed that Glomus, Acaulospora, Enthrophospora, Gigaspora and Scutellospora genus was found in the area. Glomus and Gigaspora are genus that found almost in all locations. The highest diversity and spore density was found in coastal vegetation communities while the highest root colonization was found in inland vegetation communities. The abundance and frequency relative of AMF’s spore showed that Glomus was the genus which has the biggest and widest distribution than other genus.
Keyword: AMF, Anak Krakatau Mount, diversity

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