Judul: Belawan putih (Tristaniopsis whiteana): antibacterial compounds and their distribution in Peat and Heath Forests Central Kalimantan
Abstrak: Biodiversity of peat forest ecosystem is highly potential. Among these potentials is the use of forest plants as medicines. One of medicinal plants found in the peat swamp forest ecosystem is from genus Tristaniopsis, for example belawan putih (Tristaniopsis whiteana). Several studies have reported the potential of this plant as an antibacterial drug. In this report, bioactive antibacterial compounds of belawan putih leaves extract and mapping the distribution of the plant in peat and heath forests, Central Kalimantan, were studied. The sample was extracted gradually using four different solvents based on polarity (n-hexane, chloroform, ethyl acetate, and methanol). The chloroform extract showed the most active in inhibiting Escherichia coli and Staphylococcus epidermidis. Isolation and purification of the chloroform extract gave 2 pure compounds, compound 1 and 2, having the same minimum inhibitor concentration (MIC) value against E. coli were 128 μg/mL. MIC values of compound 1 and 2 against S. epidermidis were 128 and > 128 μg/mL, respectively. Based on structure elucidation using nuclear magnetic resonance proton (1H-NMR), compound 1 was estimated to have aromatic, alkoxy, methine, methylene, and methyl groups. Structure elucidation using ultraviolet and infrared spectrophotometers, 1H-NMR, 13C-NMR, DEPT, HMBC, and HMQC, compound 2 was found be betulinic acid. This is the first report of the occurrence of this compound in belawan putih and genus Tristaniopsis. One potential of belawan putih commonly used by people around forest areas is the use as medicines. Therefore, it is necessary to protect this species from the threat of extinction. One of the survey criteria in determining priority to protect the species is to find the distribution pattern of the species population. Ecological parameters of belawan putih in heath and peat forest Bawan, Central Kalimantan, was observed and measured on 6 plot in each forest by purposive sampling method. The plot was circle with radius of 10 m, so the 6 plot have area of 0.5 hectares. Based on Morissita method, the distribution pattern of belawan putih in heath and peat forest was clumped type.
Keyword: antibacterial, Central Kalimantan, heath forest, peat forest, Tristaniopsis whiteana

Judul: Komposisi Vegetasi dan Potensi Tumbuhan Obat di Hutan Kerangas Kabupaten Belitung Timur Provinsi Kepulauan Bangka Belitung
Abstrak: Heath forest on East Belitung is thought to have a diversity of plant species that can be used for medications. However, the information about it has not been revealed yet. Therefore, research about composition of vegetation and potential medicinal plants in the heath forest is necessary. This research was conducted in the primay heath forest (Rimba), secondary heath forest (Bebak) and particular heath forest (Padang) at East Belitung on July to Agustus 2011. The collected data includes species of plants (local name and scientific name), species of plants used medicine and part of plants that is used for medicine. Methods that is used to collect the data is the analysis of vegetation and interview method. Analysis vegetation was done by using combination of line and compartment method. The number of lines in each forest type are 10 with each line size is 10 m × 100 m and the distance between the lines is 50 m. The research results 224 species of plants in the heath forest obtained from different habitus and growth rates. Species with the highest value of importance on seedling, bush/shrub, herbaceous, liana, rattan and pandan is the samak (Syzygium lepidocarpa) amounted to 20.2% in the primary heath forest, pulas (Guioa pleuropteris) amounted to 12.57% in the secondary heath forest and kucai padang (Fimbristylis sp.) amounted to 51.14% in the particular heath forest. Species with the highest value of important on sapling is betor belulang (Calophyllum lanigerum) amounted to 17.27% in the primary heath forest, kiras (Garcinia hombroniana) amounted to 21.50% in the secondary heath forest and sekuncong (Leptospermum flavescens) amounted to 88.46% in the particular heath forest. Species with the highest value of important on tree is seru (Schima wallichii) amounted to 53.36% in primary heath forest, seru (Schima wallichii) amounted to 103% in secondary heath forest and sekuncong (Leptospermum flavescens) amounted to 180.2% in the particular heath forest. The number of medicinal plant species are identified based on knowledge of local communities as much as 101 species. Plant family which were most widely utilized is Myrtaceae. Tree is the most common habitus of medicinal plant to be used. The part of plants which is widely used is root and the most numerous group of diseases cured with medicinal plant is diseases of body resilience system (fever). Composition of vegetation in heath forest is potential as a germ plasm reserve of medicinal plants in Indonesia. Heath forest resources conservation can support sustainability of species and benefits to community around the forest.
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Judul: Prediksi Kurs Rupiah Terhadap Dollar Amerika Menggunakan Persamaan Schrodinger Nonlinear Diselesaikan dengan Metode Runge Kutta Orde Empat.
Abstrak: Kurs adalah pertukaran antara dua mata uang yang berbeda, yaitu perbandingan nilai atau harga antara kedua mata uang tersebut. Prediksi kurs rupiah dapat dimodelkan dengan persamaan Schrodinger nonlinear yang dihitung dengan metode Runge Kutta orde empat. Parameter yang terdapat dalam persamaan Schrodinger nonlinear dianalogikan ke dalam parameter ekonomi yang diasumsikan sebagai faktor-faktor yang mempengaruhi kurs rupiah. Faktor-faktor tersebut antara lain pergerakan atau pertumbuhan rata-rata kurs rupiah, tingkat inflasi, tingkat suku bunga, kecepatan rata-rata perubahan kurs rupiah, dan Produk Domestik Bruto (PDB). Penelitian ini bertujuan untuk mengetahui nilai prediksi kurs rupiah dari perubahan pergerakan kurs rupiah, sehingga pergerakan kurs rupiah yang fluktuatif akan mempengaruhi nilai prediksinya. Data hasil prediksi nilai kurs rupiah terhadap dolar Amerika dibandingkan dengan data kurs aktual. Hasil prediksi kurs rupiah dari persamaan Schrodinger nonlinear menggunakan metode Runge Kutta orde empat menghasilkan persentase error tertinggi dibawah 5% disetiap bulannya dan menghasilkan nilai Mean Absolute Percentage Error (MAPE) sebesar 0.4786%.
Keyword: kurs rupiah, parameter Schrodinger, Runge Kutta orde empat, Schrodinger nonlinear