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
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Judul: Pengaruh Jarak dari Hutan dan Kondisi Lanskap Pertanian terhadap Keanekaragaman Hymenoptera
Abstrak: Landscape conditions have an enormous role in determining the level of biodiversity. Complexity of habitats has been known to be associated with the increase of spesies richness. The purpose of this research is to study the effect of distance from the forest and agricultural landscapes toward abundance and diversity of hymenoptera in vegetable crops. A survey was conducted in the month of August 2012 until October 2012 at eight different habitats in Cisarua, Megamendung, Tamansari, Caringin and Cigombong from Bogor District. The habitat observed is divided into four criteria: habitats that are located within 0 to 500 m, 500 to 1000 m, 1000 to 1500 m, and 1500 to 2600 m from the forest. Sampling was done by installing 4 to 15 Yellow Pan Trap (YPT) in each locations. Altogether there were 779 individuals belonging to 26 families and 130 species that were collected. Species richness was found in the habitats that are located 1500 to 2600 m from the forest.Based on Shannon's index, the highest diversity was found to be on landscape with the distance of 1000 to 1500 m from the forest (B01) in sub-district Tamansari. Spesies similarity was found to be quite with less than 50% between different habitats. However, species composition between different habitats does not show is any difference. Result of the study does not show that diversity of Hymenoptera is effected by distance from forest instead it is more influenced by conditions and type of agricultural landscapes.
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Judul: igenvalues and Eigenvectors of Tridiagonal Matrix with Non Constant and Recurrent Diagonal Entries.
Abstrak: Matriks tridiagonal adalah suatu matriks yang mempunyai entri-entri bernilai nol kecuali pada diagonal utama, di bawah diagonal utama (subdiagonal) dan di atas diagonal utama (superdiagonal). Entri pada diagonal utama tidak konstan dan berulang. Setiap entri pada matriks tridiagonal ini adalah bilangan kompleks. Dalam karya ilmiah ini, akan dibuktikan 3 teorema untuk menentukan nilai eigen dengan 2 kasus dan 1 teorema untuk menentukan vektor eigen. Teorema pertama menentukan polinomial karakteristik dari matriks tridiagonal. Polinomial karakteristik dari matriks tridiagonal tersebut digunakan untuk menentukan nilai eigen pada teorema kedua dan ketiga serta menentukan vektor eigen pada teorema keempat
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