Judul: Soil Fauna Diversity in the Agroforestry Areas of Mount Halimun Salak National Park
Abstrak: Taman Nasional Gunung Halimun Salak (TNGHS) merupakan area konservasi yang melibatkan masyarakat dalam pengelolaan lahan dengan sistem agroforestri. Keberadaan fauna tanah di lahan agroforestri diperlukan sebagai indikator kesuburan tanah. Penelitian bertujuan mengidentifikasi keanekaragaman fauna tanah, menganalisis pengaruh kerapatan vegetasi serta hubungan faktor lingkungan terhadap keanekaragaman fauna tanah di lahan agroforestri TNGHS. Metode pengambilan sampel fauna tanah dengan pitfall trap. Analisis data dengan mengukur kelimpahan, indeks keanekaragaman (H’), kekayaan (DMg) dan kemerataan (E) spesies, uji t paired dan korelasi pearson. Hasil penelitian ditemukan 15 ordo dan 32 famili dengan famili Formicidae (Hymenoptera) paling banyak ditemukan. Indeks H’ dan DMg pada kerapatan tinggi lebih besar (0,72 dan 3,28) dibandingkan dengan kerapatan sedang (0,63 dan 2,95). Indeks E pada kedua kerapatan tergolong rendah dan menunjukkan adanya dominansi dari famili Formicidae. Hasil uji t paired menunjukkan tidak ada perbedaan yang signifikan antara kerapatan tinggi dan sedang. Keanekaragaman fauna tanah berkorelasi sangat rendah dengan pH tanah, respirasi, dan intensitas cahaya. Sementara dengan ketebalan serasah korelasinya rendah, dan dengan suhu tanah korelasinya sedang., Gunung Halimun Salak National Park (TNGHS) is a conservation area that involves communities in land management with agroforestry systems. The presence of soil fauna in agroforestry land is needed as an indicator of soil fertility. The study aims to identify the diversity of soil fauna, analyze the effect of vegetation density and the relationship of environmental factors on soil fauna diversity in agroforestry land TNGHS. The method of sampling soil fauna with pitfall traps. Data analysis by measuring the abundance, diversity index (H'), richness (DMg) and evenness (E) of species, paired t test and Pearson correlation. The results of study found 15 orders and 32 families with Formicidae family (Hymenoptera) found the most. The H' and DMg indices at high density were greater (0.72 and 3.28) than those at medium density (0.63 and 2.95). The E index in both densities was low and indicated the dominance of Formicidae family. The paired t test results showed no significant difference between high and medium densities. Soil fauna diversity was very lowly correlated with soil pH, respiration, and light intensity. While with litter thickness the correlation is low, and with soil temperature the correlation is moderate.
Keyword: Agroforestri, Fauna tanah, Keanekaragaman, Taman Nasional Gunung Halimun Salak

Judul: Diversity of Soil Arthropods in the Core Zone of Mount Halimun Salak National Park
Abstrak: Arthropoda tanah merupakan salah satu kelompok fauna yang hidup di tanah dan berperan dalam memengaruhi laju pembentukan tanah, dan siklus hara dalam ekosistem. Penelitian ini bertujuan untuk mengidentifikasi keanekaragaman Arthropoda tanah yang didapatkan pada Zona Inti Taman Nasional Gunung Halimun Salak (TNGHS), dan menganalisis pengaruh antara dua kelas kerapatan vegetasi, faktor edafis maupun faktor klimatis terhadap keanekaragaman Arthropoda tanah yang ditemukan pada kerapatan vegetasi di Zona Inti TNGHS. Metode yang digunakan dalam pengambilan sampel Arthropoda tanah menggunakan metode pitfall trap dan hand sorting. Data keanekaragaman Arthropoda tanah dengan faktor lingkungan dianalisis menggunakan uji Korelasi Pearson dan uji Paired Sample t-Test. Hasil penelitian ditemukan 16 ordo dan 39 famili yang berbeda dan didominasi oleh famili Formicidae (Hymenoptera) pada kedua kelas kerapatan vegetasi. Indeks keanekaragaman Arthropoda tanah (H’) pada kedua kelas kerapatan berjumlah 1,24 dan 1,44. Hasil uji t-Test menunjukkan tidak adanya perbedaan yang signifikan antara kedua kelas kerapatan vegetasi. Faktor edafis dan faktor klimatis memiliki hubungan korelasi baik ke arah positif maupun negatif dengan keanekaragaman Arthropoda tanah.
Keyword: Arthropoda tanah, edafis, klimatis, Taman Nasional Gunung Halimun Salak

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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