Judul: Implikasi eksistensi Chromolaena odorata (L.) King & Robinson (Asteraceae) dan agens hayatinya Cecidochares connexa Macquart (Diptera: Tephritidae) terhadap struktur komunitas serangga dan tumbuhan lokal
Abstrak: Penelitian ini bertujuan untuk mempelajari distribusi dan kelimpahan populasi C. odorata dan agens hayatinya C. connexa, serta mempelajari struktur komunitas serangga dan tumbuhan lokal di daerah yang telah diinvasi oleh C. odorata. Kegiatan yang dilakukan adalah survei lokasi penelitian, analisis vegetasi, dan koleksi serangga. Penelitian ini berlokasi di Jawa Barat yang meliputi daerah Parung Panjang, Setu, Darmaga, Gunung Bunder, Gunung Salak, Gunung Halimun, Pakuwon, Ciawi, Cisarua, dan Cianjur. Lokasi penelitian tersebut ditentukan berdasarkan metode purposive sampling. Analisis vegetasi dilakukan dengan metode transek yang dikombinasikan dengan metode kuadrat. Koleksi serangga dilakukan di dalam petak contoh dengan memasang perangkap pitfall trap dan yellow pan trap, sedangkan perangkap malaise trap diletakkan secara diagonal diantara jalur transek.
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Judul: Implikasi eksistensi chromolaena odorata (l.) King & robinson (asteraceae) dan agens hayatinya cecidochares connexa macquart (diptera: tephritidae) terhadap struktur komunitas serangga dan tumbuhan lokal
Abstrak: ALAL HUDA JAYA. S. Implication of existence both of Chromolaena odorata (L.) King & Robinson (Asteraceae) and its biological control agent - Cecidochares connexa Macquart (Diptera: Tephritidae) to local plant and insect community structure. Supervisors: DAMAYANTI BUCHORI and SOEKISMAN TJITROSEMITO. The aims of this research were (1) to study density and population distribution of C. odorata and its biological control agent - C. connexa, and (2) to study local plant and insect community structure in invaded area of C. odorata. Several activities have been conducted i.e. survey of research sites, vegetation analysis, and insect sampling. The study sites were selected base on purposive sampling method. All area located in Bogor district (Parung Panjang, Setu, Darmaga, Gunung Bunder, Ciawi, and Cisarua), Sukabumi district (Gunung Salak, Gunung Halimun, and Pakuwon), and Cianjur district. Analysis of vegetation were conducted using combination of transect and quadrate method. Insect were sampled by setting up several traps inside the plots. Pitfall trap and yellow pan trap were set up inside the plot, whereas malaise trap were placed between two transect lines. The result found that invasive exotic plant species (C. odorata) spread on whole study sites and well-growth on different habitat types (plantations, production forest, low land, and high land). Their population densities tend to decrease with increasing altitude. The occurrences of C. odorata co-exist with its biological control, the gall flies C. connexa. Almost all study sites (except Gunung Halimun and Cianjur) found these flies. Recently, C. connexa have established and wide spread, although the present of barrier (like mountain) is restriction factor for distribution of flies in West Java. Over 131.132 individual of plants consist of 21 families and 44 species were identified co-exist with C. odorata in Bogor area (Parung Panjang, Setu, Darmaga, and Gunung Bunder). In the same area, over 24.213 individual of insect consist of 14 orders, 132 families, and 568 species were found in C. odorata habitat. Three dominance insect orders i.e. Hymenoptera, Diptera, and Hemiptera were collected with high species richness and abundance. Implication of existence of C. odorata caused replacement local plant species and homogenization habitat on spatial scale. Introduction of C. odorata and its biological control agent caused and consequently associate with local insects.
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Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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