Judul: Keragaman serangga yang berasosiasi dengan tanaman caisim (Brassica rapa var. chinensis L.: Cruciferae) pada area pertanian tepi hutan
Abstrak: The aim of the research was to study insect diversity associated with chinese cabbage (Srassica rcpipa var. chi~remis}i n forest edge agicr;!t;re. &ese cabbzge were p!mied h 9.x Iocations with different distance, they were 0 m and 400 m frm the forest margin. Insect ebs=r:&ccs -xeze &nt eveiy two hoaxs, ficm 08 am =ti! 02 pm. Qbm11n-n~w ere s81?ed hfii 2 until 45 day after planted PAP). Sample of insects were caught by sweep net fbr identification. Idc~tXedin sect were classified based on their role as phytophagous, pollinator, and predator. Environment condition, include: temperature, humidity, and Iight intensity were measured Data were analysed by Shetnnon's diversity index @'j and evennes Q and s&J sidW~in-d ex (Cj). Total number of phytophagous, polhator, and predator insect were tested by t-fmt. Insect diversity associated with chinese cabbage were phytophagous (67%), pollinator (14%), and predator (19%). Insect diversity in 0 m was higher @'=2.498, E= 0.304) than 400 m &om the forest edge (IT-Z.344, E4298). Abundance of phytophagous and pollinator insect in 400 m was lower than in 0 m fiom the edge, whiIe predatory insect was higher in 400 m. Based on the observation time, the number of individual and species of insect were highest at 08 am, lower at 10 am d l12 pm and lowest at 02 pm. Based on plant age, the number of individual aad insect species were fluctuation Simillarity of insect associated with chinese cabbage in two bcations was higher (Cj=0.9).
Keyword: 

Judul: Komunitas Serangga Penyerbuk pada Habitat dan Jarak Berbeda dari Tepi Hutan Taman Nasional Gunung Halimun Salak
Abstrak: Pollination service is one of many services that forest can provide for farming near to the forest which definitely harbors a high biodiversity of pollinator insects. Yet, forest degradation by farming activities is a threat for pollinator insect diversity, so there must some awareness to be given especially for the villagers about how important their forest is for their farms. The objectives of this research are: (1) to identify caisin’s (Brassica rapa L.) flower-visitor insects and to determine its function in its community, (2) to count abundance and species of pollinator insects and also to measure diversity index in distances from the forest, (3) to analyze spatial distribution of pollinator insects and its composition in every plot base on its similarity index, (4) to show the correlation of forest distance with the abundance and its diversity. Observation on caisin’s flower-visitor insects were carried out over 20 days period from 28 December 2006 – 16 January 2007, in margin forest of Gunung Halimun-Salak National Park, Sirnarasa Village, District of Sukabumi, Province of West Java. All insect visiting the flowers were counted by using fixed sampling method within 30 minutes observation period in each site that consisted of 20 flowering caisin plants. The forest distance factor giving the best fit was shown in a simple linear regression model on scatter plot graphic. This study showed that 1312 insects are found in caisin’s flower but only 747 insects or 56,94% of them are real pollinator insects which are representative of 32 pollinator species within 15 sites observation along the margin forest. Higher densities of pollinator insects are found near to forest’s margin than at greater distances from forest. The abundances of pollinator insects are usually high in open areas that provide fewer shade trees. Species diversity and abundance of pollinator insects were decreasing within distance from the forest despite there are many factors which may influence the abundance. The most influencing factor is the blossom cover of caisin in site observation that significantly has a positive correlation with flower visitation by insects. The other factors such as temperature and humidity did not significantly influence the flower visitation by insects
Keyword: 

Judul: Formulasi Hamilton Untuk Menggambarkan Deformasi Gelombang Soliter Dengan Dasar Tidak Rata Pada Fluida Dua Lapisan
Abstrak: Gelombang internal adalah suatu gelombang yang muncul di bawah permukaan laut sehingga gelombang ini tidak teramati secara kasat mata. Formulasi Hamilton dirumuskan untuk menjelaskan gerak gelombang ini. Dalam hal ini diasumsikan bahwa fluida yang ditinjau terdiri atas dua lapisan dengan masing-masing lapisan memiliki rapat massa yang konstan. Selain itu, diasumsikan pula fluida yang ditinjau berupa fluida tak mampat (incompressible) dan tak kental (invicid). Formulasi Hamilton dilakukan dengan meninjau fluida dua lapisan yang berada pada domain yang dibatasi oleh batas atas yang rata dan batas bawah yang tidak rata. Hamilton (energi total)-nya didefinisikan sebagai penjumlahan antara energi kinetik dan energi potensialnya. Karena energi kinetik tidak secara eksplisit dinyatakan dalam peubah fisis, maka digunakan metode asimtotik untuk menentukan energi totalnya. Dalam hal ini diasumsikan bahwa gelombang interfacial yang ditinjau cukup panjang, dan amplitudo yang cukup kecil. Persamaan Korteweg de- Vries (KdV) diperoleh, jika disumsikan bahwa gelombang interfacial hanya merambat pada satu arah, sedangkan jika gelombang tersebut merambat ke dua arah, diperoleh persamaan Boussinesq.
Keyword: