Judul: Anti-termite Activity of Tamanu Bark Extract (Calophyllum inophyllum L.).
Abstrak: Rayap tanah adalah organisme perusak kayu yang umumnya ditemukan menyerang material berbahan dasar kayu. Rayap ini sangat merugikan karena merusak komponen bangunan dan rumah serta produk kayu lainnya. Salah satu cara untuk meningkatkan daya tahan kayu dari serangan organisme perusak adalah dengan pengawetan kayu. Nyamplung (Calophyllum inophyllum L.) merupakan tumbuhan tropis yang banyak ditemukan di daerah pesisir Indonesia. C. inophyllum dikenal sebagai sumber yang kaya akan zat ekstraktif yang dianggap berpotensi sebagai pengawet kayu. Penelitian ini bertujuan untuk menganalisis kadar zat ekstraktif kulit batang C. inophyllum, menganalisis aktivitas ekstraktif kulit batang C. inophyllum terhadap rayap tanah, dan mengidentifikasi senyawa aktif yang terkandung di dalam zat ekstraktif kulit batang C. inophyllum yang bersifat toksik terhadap rayap tanah Coptotermes curvignathus. Serbuk kulit batang C. inophyllum diekstraksi secara berurutan dengan menggunakan pelarut n-heksana, etil asetat, dan metanol dengan metode maserasi. Pengujian antirayap dilakukan dengan menggunakan paper disc method dengan dua cara yaitu no-choiche dan two choice-test. Kertas uji Whatman berdiameter 20 mm ditetesi dengan larutan ekstrak dengan konsentrasi 4%, 6%, 8%, dan 10% (b/v). Kemudian, kertas dimasukkan ke dalam tabung akrilik, lalu ditambahkan rayap tanah C. curvignathus. Kasta pekerja sebanyak 45 ekor untuk no-choice, dan 90 ekor untuk two-choice test. Sementara itu, kasta prajurit sebanyak lima ekor untuk no-choice, dan 10 ekor untuk two-choice test. Pengujian dilakukan selama tujuh hari. Parameter yang digunakan dalam pengujian ini adalah mortalitas rayap dan kehilangan berat kertas uji. Hasil penelitian menunjukkan bahwa total kandungan ekstraktif kulit batang C. inophyllum adalah 30,24%. Zat ekstraktif kulit batang C. inophyllum memiliki aktivitas anti rayap. Ekstrak yang paling aktif sebagai antirayap ditunjukkan oleh ekstrak n-heksana dan etil asetat. Ekstrak n-heksana teridentifikasi mengandung senyawa friedelan-3-one, sedangkan ekstrak etil asetat mengandung senyawa 1,2-benzene dicarboxylic acid, dinonyl ester dan friedelan-3-one. Senyawa-senyawa tersebut diduga berperan dalam aktivitas antirayap pada ekstraktif kulit batang C. inophyllum., Subterranean termites are wood-destroying organisms that are commonly found attacking wood-based materials. They cause economic loss because they damage the components of houses and buildings. One way to increase the resistance of wood to degrading organisms is by wood preservation. Tamanu (Calophyllum inophyllum L.) is a tropical plant commonly found in coastal areas in Indonesia. C. inophyllum is a rich source of extractive substances that have potential as wood preservatives. This study aimed to analyze the extractive content of C. inophyllum bark, to analyze the extractive activity of C. inophyllum bark against subterranean termites, and to identify active compounds contained in the extract of C. inophyllum bark that are toxic to subterranean termites Coptotermes curvignathus. C. inophyllum bark powder was extracted sequentially using n-hexane, ethyl acetate, and methanol solvents by the maceration method. The anti-termite testing was carried out using two paper disc methods: no-choice and two-choice. Some Whatman test papers were dripped with extract solution in concentrations of 4%, 6%, 8%, and 10% (w/v), then the paper was put into an acrylic tube. Then, the paper disc sample was put into an acrylic tube, and the paper was put into an acrylic tube and subterranean termites C. curvignathus were added. The worker caste was 45 for the no-choice test and 90 for
Keyword: Calophyllum inophyllum, Coptotermes curvignathus, natural wood preservative, subterranean termite, wood-destroying organisms

Judul: Bioactivity of Cajuput Seedling N-Hexane Extract as an Attractant for Subteranian Termite Coptotermes curvignathus Holmgren (Isoptera: Kalotermitidae)
Abstrak: Serangan rayap tanah (subterranean termite) terhadap anakan kayu putih (Melaleuca cajuputi) terjadi secara masif di cukup banyak Kesatuan Pemangkuan Hutan (KPH) Perum Perhutani di Pulau Jawa. Diduga terjadinya serangan tersebut berkaitan dengan komponen kimia pada akar anakan kayu putih. Suatu penelitian laboratoris telah dilakukan untuk mengetahui bioaktivitas ekstrak akar anakan kayu putih sebagai pemikat (attractant) bagi rayap tanah Coptotermes curvignathus Holmgren (Isoptera: Rhinotermitidae). Proses ekstraksi mengacu pada ASTM D1108-96 dan karakterisasi ekstrak dilakukan menggunakan alat GC-MS. Pengujian bioaktivitas ekstrak dilakukan dengan metode attractiveness bioassay dan no choice feeding bioassay. Hasil penelitian menunjukkan rata-rata rendemen ekstraksi akar anakan kayu putih adalah 4,94%. Atraktivitas larutan ekstrak pada konsentrasi 0,5%, 0,75%, dan 1% masing-masing mencapai 45,33%, 62%, dan 74,67%. Mortalitas rayap C. curvignathus berkisar antara 9,63%-24.44%. Lethal concentration-50 (LC50) ekstrak akar anakan kayu putih adalah 2,45% (non toksik). Hasil analisis GCMS menujukan bahwa ekstrak mengandung asam linoleat yang berpotensi sebagai bahan pemikat serangga., Subterranean termite attacks on cajuput seedling (Melaleuca cajuputi) occured massively in quite a number of Perum Perhutani Forest Management Units (KPH) in Java Island. It is possibly due to the chemical components of the root of the cajuput seedling. A laboratory study was conducted to determine the bioactivity of cajuput root extract as an attractant for the subterranean termite Coptotermes curvignathus Holmgren (Isoptera: Rhinotermitidae). Extraction process refers to ASTM D1108-96 and extract characterization was carried out using GC-MS. The bioactivity test of the extract was carried out using the attractiveness and no choice feeding bioassay methods. The results showed that the average yield of the extract was 4,94%. The attractiveness of the extract solution at concentrations of 0,5%, 0,75%, and 1% on C. curvignathus reached 45,33%, 62%, and 74,67%, respectively. Meanwhile the mortality of C. curvignathus ranged from 9.63%-24.44%. The lethal concentration-50 (LC50) was 2.45% (non-toxic). GCMS analysis revealed that the extract contained linoleic acid, which has been reported as a feeding stimulant.
Keyword: attractivity, LC 50, linoleic acid, mortality, termite attractant

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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