Judul: Studi Perilaku Makan dan Palatabilitas Rekrekan (Presbytis fredericae Sody, 1930) di Kawasan Hutan dan Perkebunan Karet Desa Gutomo Kabupaten Pekalongan Provinsi Jawa Tengah
Abstrak: Javan Fuscous Langurs is one of the endemic primate in Java island and was declared as protected animal by law in Indonesia and also IUCN define it as a species with category data defficience. In primate it self, the phylogenetic and ecological difference influence to feeding behavior and it makes every species with different habitat have different feeding behavior. Then, it is important to us to have data and information about their feeding behavior. The purpose of this research are to get information about feeding ecology of Javan Fuscous Langurs that consist of feeding behavior, composition and diversity of the foods, foods preference and also some factors that influence feeding behavior. The result from this research expected can consider as one of the substance for doing good habitat management for Javan Fuscous Langurs. Data collection were done with period 6 months in the forest area and rubber plantation dusun Sidoguno. The equipments are map, camera, GPS, binocular, stopwatch, compass, tallysheet, clinometers, rope, software Arcview 3.2 and stationery. Whereas, the objects are 2 groups of Javan Fuscous Langurs with different type for each other. Group A has type 1 male-multi female with composition 1 adult male, 4 adult female, 1 subadult female, 1 juvenille female and 2 infants. Group B has type all male with composition 2 adult male, 2 sub adult male, and 1 juvenille male. The method for observed used scan sampling and for record data used continous recording method and the data will be analyzed by descriptive statistic and on graphs . Daily activity of Javan Fuscous Langurs consist of resting (57,66%), feeding (29,33%), moving (11,51%), social activity (0,93%) and calling (0,43%). This 2 groups of Javan Fuscous Langurs has different homerange, group A has homerange 54,55 ha and group B has smaller homerange than group A (48,16 Ha) with overlap between two of them around 2,49 Ha. But then, group B has daily range more longer than group A, it around 694-1269 m where daily range of Group A only 576-1146 m. in the feeding behavior, group A more often used sit posture and used space in the tree canopy between top-middle with height around 6-10 m, group B more often used sit posture in space between middle-edge with height around 0-5 m. group A feed 56 species from 34 family of plants as their foods and group B feed 45 species from 29 family with variation foods composition such as young leaves, seeds and fruits. Plant species that have great contribute as foods for the two species is Hevea brasiliensis. Chisocheton divergens become species with the highest ratio selection in the group A and Pangium edule. for the group B. Two groups have different vegetation structure and composition. In the home range of group A were identified 170 trees/ha with lbds 27,51 m2/ha and the diversity index for tree level is 3,21. In the homerange of the Group B were identified 301 trees/ha with lbds 20,62 m2/ha and the diversity index for tree level is 1,24. Conclusions from this research are feeding behavior of Javan Fuscous Langurs is
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Judul: Variasi Geografis dan Lingkungan dalam Anggaran Kegiatan dan Pola Makan Lutung Jawa (Trachypithecus auratus)
Abstrak: Environmental and climatic conditions affect food abundance, affecting animals' dietary composition and diversity. Activity budgets are key information for evaluating the feeding strategy of primates. This study aims to analyze the effects of geographic and environmental factors on activity budget and dietary habits of Javan langurs (Trachypithecus auratus) across their geographical range or among forest types. This study’s data were gathered by conducting a web-based survey of the activity budget and dietary habits of the Javan langur. This study analyzed relationships between the geographical/environmental and activity, dietary composition, and social/behavioral aspects by the Spearman’s rank correlation tests and tested differences in the above variables among three forest types by the Kruskal-Wallis tests. The langurs’ diets were composed of foliage (49.0-75.7%), fruits (21.6-48.1%), and flowers (2.7-23.0%). The activities of the langurs were mainly composed of feeding (range: 20.2-44.2%), moving (9.8- 32.1%), resting (9.3-43.6%), and social behavior (2.5-28.9%). There were no significant differences between forest types and activity budget and dietary habits of the langurs and no significant correlations between geographic/environmental variations and their activity budget and dietary habits. The folivorous-based diets and their specialized digestive strategy would be the main reason for the lack of regional variation in activity and dietary habits.
Keyword: Colobines, conservation, feeding, folivorous, forest types

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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