Judul: Produktivitas dan sifat fisiko kimia pati aren (Arenga pinnata (Wurmb) Merr) di pengolah kedung halang Kabupaten Bogor
Abstrak: Penelitian ini bertujuan untuk menentukan pro- duktivitas pati dari pohon aren, dan mempelajari sifat fisiko kimia pati aren yang dihasilkan secara komersial. Metode penelitian terdiri dari penelitian la- pang dan analisa laboratorium. Penelitian lapang untuk menentukan kriteria yang relevan dengan produktivitas yaitu tinggi pohon, diameter batang, berat empulur dan batang. Pati sebagai produk olahan batang aren di- analisa untuk kadar air, kadar pati, kadar amilosa, de- rajat keputihan, keasaman, suhu gelatinisasi, kehalusan, rendemen, bentuk dan ukuran granula pati, serta extrak- tabilitas. Selain itu juga dianalisa makroskopis batang, mikroskopis empulur dan susunan kimia empulur. Hasil penelitian lapang menunjukkan bahwa untuk menentukan produktivitas pohon aren kriteria pengelom- pokkan diameter lebih tinggi relevansinga dibanding pe- ngelompokkan tinggi pohon. Tinggi pohon aren yang ditebang berukuran anta- ra 5 -13m, dapat dikelompokkan menjadi 3, masing-masing 5 - 48m, 8 <10m, dan 10m. Kadar pati empulur dari - masing-masing kelompok adalah 31.50%, 31.81%, dan 28,57%. ...
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Judul: Potency and Effect of Organic Bio-fertilizer on Aren (Arenga pinnata Merr.) Stands in Sungkap Village, Central Bangka Regency
Abstrak: Aren memiliki nilai ekonomis dan ekologis tinggi karena hampir semua bagiannya dapat dimanfaatkan. Potensi aren cukup menjanjikan karena dapat hidup di berbagai kondisi tanah asalkan tercukupinya unsur hara. Penelitian bertujuan menduga potensi tegakan aren, produksi nira, pengaruh pupuk terhadap tegakan aren, dan rencana pengembangan aren di Desa Sungkap. Penelitian dilakukan dengan pemberian pupuk organik hayati merek Pupuk Ghaly Organik IPB dengan 45 sampel aren dan diuji dengan ANOVA. Hasil menunjukkan aren di Desa Sungkap menyebar di lahan budidaya dan liar yang keduanya menyebar secara berkelompok. Produksi nira yang tertinggi terjadi di lahan liar. Indikator tumbuhan dengan pemupukan seperti tinggi batang, lilit batang, jumlah daun, dan produksi nira terjadi secara signifikan, sedangkan pH dan brix nira tidak signifikan. Tutupan lahan kebun campuran diasumsikan sebagai habitat aren yang potensial, namun potensi tegakan aren masih belum optimal, sehingga perlu dilakukan budidaya dengan sistem agroforestri. Hasil penelitian dapat digunakan sebagai acuan dalam menduga potensi tegakan dan pengaruh pemupukan terhadap tegakan aren., Sugar palm has high economic and ecological value as almost all of its parts can be utilized. The potential of sugar palm in Sungkap Village is promising because it can thrive in various soil conditions as long as there is sufficient nutrient supply. The research aims to estimate the potential of sugar palm stands, sap production, the influence of fertilizer on sugar palm stands, and development plans for sugar palm in Sungkap Village. The research was conducted by applying organic bio-fertilizer branded Ghaly Organik IPB fertilizer to 45 samples of sugar palm and tested using ANOVA. The results indicate that sugar palm in Sungkap Village are distributed in both cultivated and wild areas, both of which are clustered. The highest sap production occurs in wild areas due to its habitat habitat. The highest sap production occurs in wild land. Plant indicators affected by fertilization such as trunk height, trunk girth, number of leaves, and sap production show significant changes, while pH and brix indicators do not. Mixed garden land cover is assumed to be a potential habitat, but the potential of sugar palm stands is still not optimal, thus cultivation with agroforestry systems are needed. The research results can be used as a reference for assessing the potential of stands and the effects of fertilization on sugar palm stands.
Keyword: budidaya, liar, potensi, pupuk, tegakan

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