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: Keanekaragaman Serangga Penyerbuk pada Pertanaman  Mentimun Pengaruh Keberadaan Habitat Alami
Abstrak: Pollination is a critical first step in sexual reproduction of flowering plants. Insect pollinator plays an important role in pollination prosess of flowering plants, including cucumber. The aims of this study are to determine the influence of natural habitats toward the diversity insect pollinators and to gain informations of the relationship between insect pollinator diversity and the number of flowers. The research was set up in six locations with different distances from the natural habitat. Three locations are categorized as being in a close proximity to natural habitat (D), which is about ≤200 m and three other locations are categorized as far from natural habitats (J), with a distance of ≥1000 m.The distance between the locations are 1.5 km. Observations were conducted by two methods, sweeping net and malaise traps. Number of flowers were counted using the amount of flower activities which open and close at four points for each by 1 m x 1 m plot. Results showed that agricultural land conditions affect the abundance of insect pollinators. The highest diversity of insects were found in the morning, e.g.- at 09:00 am and 11:00 am. No correlation were found between the numbers of species of insect pollinators and the numbers of flower.
Keyword: pollination., natural habitat, insect pollinator, diversity

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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