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: Kohabitasi Ruang Lutung Sentarum (Presbytis chrysomelas cruciger) di Kawasan Bukit Semujan Taman Nasional Danau Sentarum.
Abstrak: Lutung sentarum (Presbytis chrysomelas cruciger) termasuk dalam kategori Critically Endangered (CE) atau terancam punah. Tujuan dari penelitian ini yaitu untuk memetakan wilayah, mengetahui tumpang tindih, dan bentuk kohabitasi primata. Penelitian ini dilaksanakan pada bulan Januari 2022 dengan menggunakan metode ad libitum sampling dan scan sampling. Hasil dari penelitian ini diketahui luas wilayah jelajah lutung sentarum sebesar 25,2 ha dan monyet ekor panjang sebesar 7,0 ha. Tumpang tindih ruang kedua primata ini terjadi pada strata C. Nilai tumpang tindih dianalisis menggunakan Indeks Jaccard penggunaan ruang vertikal lutung sentarum dan monyet ekor panjang yaitu 0,13, sedangkan Indeks Jaccard terhadap jumlah jenis pakan sebesar 0,56. Nilai tumpang tindih kedua primata berdasarkan jenis pakan dengan perhitungan MacArthur dan Levin sebesar 0,82. Perhitungan luas relung ekologi menggunakan persamaan Smith untuk lutung sentarum pada taraf nyata (selang kepercayaan 95%) adalah FT =0,795 dengan nilai batas bawah dan batas atas sebesar 0,625 ≤ FT ≥ 0,918, monyet ekor panjang senilai FT = 0,664 dengan nilai batas bawah dan batas atas sebesar 0,846 ≤ FT ≥ 0,429. Kata kunci: Danau Sentarum, kohabitasi, Lutung sentarum, Monyet ekor panjang, Bornean Langur (Presbytis chrysomelas ssp. cruciger) is included in the Critically Endangered (CE) category or threatened with extinction. The purpose of this study was to map the area, find out the overlap, and the form of cohabitation of the primates. This research was conducted in January 2022 using ad libitum sampling and scan sampling methods. The results of this study indicated that the roaming area of the Bornean langur is 25,2 ha and the long-tailed monkey is 7,0 ha. The spatial overlap of these two primates occurs in strata C. The value of the overlap was analyzed using the Jaccard Index of using vertical space for langur sentarum and long-tailed monkeys, which is 0.13, while the Jaccard Index for the number of types of feed is 0.56. The overlapping value of the two primates based on the type of feed calculated by MacArthur and Levin was 0.82. Calculation of ecological niche area using Smith's equation for langur sentarum at a significant level (95% confidence interval) for langur sentarum is FT = 0.795 with the lower and upper limit values of 0.625≤ FT ≥ 0.918, long-tailed monkeys worth FT = 0.664 with the lower and upper limit values of 0.846 ≤ FT ≥0.429. Keywords: Bornean Langur, Cohabitation, Long tailed monkey, Sentarum Lake
Keyword: Kohabitasi, Danau Sentarum, Lutung Sentarum, Monyet Ekor Panjang

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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