Judul: Desain Agroforestri pada Lahan Kritis (Studi Kasus di Kecamatan Indrapuri, Kabupaten Aceh Besar)
Abstrak: Usaha-usaha pertanian tradisional yang dilakukan dengan mengkonversi lahan hutan menjadi lahan pertanian, sering menjadi penyebab terjadinya lahan kritis. Di Indonesia praktek-praktek usaha tani dan pemanfaatan lahan yang tidak atau kurang memperhatikan kaidah-kaidah konservasi tanah dan air menyebabkan timbulnya lahan kritis, erosi, bencana kekeringan, serta penurunan kualitas dan kuantitas hasil pertanian. Kabupaten Aceh Besar sebagian besar lahannya terdiri dari lahan kritis. Luas lahan kritis Kabupaten Aceh Besar mencapai 31.319 ha. Tindakan yang bijak diperlukan dalam merehabilitasi lahan kritis sehingga dapat meningkatkan produktivitas lahan juga dapat menciptakan penggunaan lahan menjadi berkelanjutan. Agroforestri adalah suatu tindakan konservasi tanah dan air melalui pengelolaan tanaman (crop management) atau metoda vegetatif untuk mengendalikan erosi dan aliran air permukaan melalui struktur tajuk berlapis, serta mempengaruhi permeabilitas dan pembentukan agregat tanah. Akumulasi serasah yang dihasilkan sistem agroforestri cukup tinggi, dan menunjang perkembangan mikro organisme tanah yang dibutuhkan untuk memelihara kesuburan tanah, pengendalian erosi, pemulihan lahan kritis. Pemanfaatan lahan kritis secara optimal dan berkelanjutan merupakan hal penting bagi petani dan masyarakat. Dari permasalahan tersebut, muncul pemikiran untuk menerapkan sistim pemanfaatan lahan secara optimal secara spatial, yang memadukan tanaman pertanian dan tanaman berkayu, menjadi bentuk sistem agroforestri untuk pengelolaan lahan kritis, dan dapat mengatasi kerusakan lingkungan serta meningkatkan produktivitas pertanian yang pada akhirnya meningkatkan pendapatan petani.
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Judul: Desain Agroforestry pada  Lahan Kritis
Abstrak: Design of agroforestry has the objectives of improving the system which has been existing and providing directives for agribusiness on the basis of physical, with pre-diagnosis and diagnosis activities which are aimed at discovering the existing constraints and problems inside the system, followed by technological intervention for system improvement and determinimg the best agroforestry system in critical and condition. Method used ini this study was identifiying the existing agroforestry system, followed by evaluation of land suitability, financial analysis and community social analysis. This study found three agroforestry system based on the existing components, namely agrisilvopasture. Evaluation of land suitability showed that in general, land suitability ratings for woody crops and perennial crops were categorized as moderately suitable (S2), while those or annual crops/non rice food crops were categorized as marginally suitable (S3). Results of financial analysis showed that all existing agroforestry system are feasible to be practiced, with highest benefit cost ratio 2.7 was found in agrisilvopasture system. On the basis of landscape consideration, species of Non-MPTS were more adapted if they were planted in hill ridge, while that of species of MPTs and perennial crops in slope and valley, and that of annual crops in valley
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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