Judul: Coexistence of Bornean Langur (Prebytis chrysomelas ssp. cruciger Thomas 1892) and Humans in Danau Sentarum National Park
Abstrak: Taman Nasional Danau Sentarum merupakan salah satu habitat lutung sentarum sebagai primata endemik Kalimantan yang hidup berkoeksistensi dengan masyarakat di sekitar habitatnya. Tujuan penelitian ini yaitu: 1) mengidentifikasi dan menganalisis pengetahuan, persepsi, dan praktik perlindungan masyarakat terhadap lutung sentarum; 2) menghitung dan menganalisis pengaruh karakteristik masyarakat serta aktivitas antropogenik terhadap keberadaan lutung; dan 3) mengidentifikasi dan menganalisis bentuk koeksistensi lutung sentarum dan manusia. Penelitian dilakukan pada Januari 2022 dengan observasi langsung dan wawancara. Hasilnya bahwa masyarakat mengetahui status perlindungan lutung sentarum melalui larangan perburuan oleh TNDS. Pengetahuan terkait perilaku umumnya melihat perilaku makan di pagi hari atau musim buah rawa pada bulan Oktober-Desember. Persepsi masyarakat tergolong cukup−sangat baik (65,5%-95%) terkait ancaman kelestarian, manfaat, dan perlindungan. Hasil uji statistik karakteristik responden dan dampak kegiatan manusia tidak memiliki hubungan baik terhadap praktik perlindungan maupun respon lutung terhadap manusia. Koeksistensi waktu terutama terjadi pada pagi hari bersamaan dengan aktivitas nelayan mencari ikan. Koeksistensi ruang tersebar pada 23 lokasi di Resort Lupak Mawang dan 10 lokasi di Resort Sepandan dan sekitarnya., Danau Sentarum National Park is one of bornean langur’s habitats in which the Borneo endemic primate lives and coexists with humans. This research was aimed to 1) identify and analyze local people’s knowledge, perception, and conservation practices of langur; 2) calculate and analyze how people’s characteristics and their activities affecting langur; then 3) identify and analyze coexistence of langur and humans. In January 2022 it was conducted by observation and interview. Results are that the knowledge regarding langur consists of its conservation encouraged by hunting probihition from national park management. Langurs were mostly spotted when they are eating in the morning or during swamp fruits season in October−December. People’s perception is in range of good enough-very good (65,5%-95%) on various topics such as threats, utilities, and conservation. People’s characteristics and anthropogenic activities are not associated statistically with neither conservation act nor langur’s responses toward humans. Coexistence chiefly happens in the morning when fishermen start looking for fish and are distributed at 10 spots in Sepandan and its vicinity along with 23 spots in Lupak Mawang.
Keyword: Danau Sentarum, bornean langur, human-primate coexistence, national park, koeksistensi, lutung sentarum

Judul: Habitat Characteristics and Feed Preferences of Bornean Langur (Presbytis chrysomelas ssp. cruciger Thomas 1892) at the Lupak Mawang Resort, Danau Sentarum National Park
Abstrak: Langur borneo adalah primata endemik pulau Kalimantan dikategorikan terancam punah (critically endangered) oleh IUCN. Tujuan dari penelitian ini adalah untuk mengidentifikasi karakteristik habitat, mengidentifikasi jenis dan preferensi pakan, serta menganalisis ketersediaan pakan langur borneo. Penelitian dilaksanakan di Resort Lupak Mawang, Taman Nasional Danau Sentarum pada bulan Juli hingga Agustus 2021. Metode pengambilan data yang digunakan yaitu pengamatan langsung dan wawancara, sedangkan metode analisis data menggunakan vegetasi untuk menganalisis dan mendeskripsikan karakteristik habitat. Hasil pengamatan menunjukan bahwa langur borneo menempati wilayah dengan ketinggian 32-257 mdpl dan kemiringan lahan 24%-45%. Aktivitas harian langur borneo lebih sering dilakukan pada strata tajuk C (4-18) m di hutan primer dan campuran. Aktivitasnya dimulai pukul 05.00 hingga 17.30 yang ditandai dengan vokalisasi. Langur borneo mengkonsumsi 27 jenis tumbuhan dari 16 famili. Persentase bagian tumbuhan yang dimakan langur borneo yaitu daun 50%, buah 30%, dan biji 20%. Langur borneo memiliki preferensi terhadap buah gita susu (Willunghbeia coriacea) yang berhabitus liana dengan persentase 36%., Bornean langur is a primate endemic to Borneo is categorized as critically endangered by the IUCN Red List. Information on the population condition and habitat of the bornean langur in Indonesia is still limited. The research was carried out at the Lupak Mawang Resort, Danau Sentarum National Park from July to August 2021. The data collection methods used were direct observation and interviews. The vegetation analysis method was used to describe its habitat characteristics. The observations shows that the bornean langur occupies an area altitude of 32 – 257 meters above sea level and a land slope of 24%–45%. The daily activities of the bornean langur are more often carried out in the C canopy strata of (4-18 m) in primary dan mixed forest. The activity starts at 05.00 until 17.30 which is marked by vocalization. The bornean langur consumed 27 species of plants from 16 families. The plant parts percentage eaten by the bornean langur are 50% leaves, 30% fruit, and 20% seeds. Bornean langur has a preference for gita milk fruit (Willunghbeia coriacea) as liana habitus plant with a percentage of 36%.
Keyword: Langur borneo, Jenis tumbuhan pakan, Karakteristik habitat

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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