Judul: Reproductive Biology of Spiny Lobster  (Panulirus homarus Linnaeus, 1758) in West Coast Waters of Lampung Province
Abstrak: Lobster pasir (Panulirus homarus) merupakan salah satu lobster yang paling sering tertangkap nelayan di perairan pesisir barat Provinsi Lampung. Hasil tangkapan lobster pasir dijual dengan harga tinggi di dalam negeri hingga diekspor ke beberapa negara. Hal tersebut membuat penangkapan lobster pasir terus mengalami peningkatan, sehingga keberadaan stok lobster berpotensi mengalami penurunan. Penelitian ini bertujuan menganalisis aspek biologi reproduksi lobster pasir. Pengambilan contoh menggunakan metode pengambilan contoh acak sederhana (PCAS) selama bulan Oktober 2021 hingga Maret 2022. Lobster pasir yang dianalisis terdiri dari 83 ekor jantan dan 93 ekor betina. Panjang karapas lobster pasir berada pada kisaran 41 mm hingga 94 mm. Fekunditas lobster pasir contoh berada pada kisaran 762-182.006 butir dengan ukuran betina pertama kali mengerami telur pada rata-rata panjang karapas 63,10 mm. Pola pemijahan lobster pasir secara parsial. Lobster pasir betina di bawah ukuran pertama kali mengerami telur masih banyak tertangkap di perairan pesisir barat Provinsi Lampung. Puncak musim pemijahan lobster pasir terjadi pada bulan November-Desember dan potensi rekrutmen tertinggi pada bulan Februari-April dan Agustus-Oktober., Spiny lobster (Panulirus homarus) is one of the lobsters most often catch by fishermen in west coast waters of Lampung Province. The catch of spiny lobster is sold at high prices domestically until it is exported to several countries. This makes the catch of spiny lobster continues to increase, so the existence of lobster stocks can potentially decrease. This study purpose to analyze the reproductive biology of spiny lobster. Sampling used the simple random sampling method during October 2021 to March 2022. The analyzed spiny lobsters consisted of 83 males and 93 females. Spiny lobster carapace length is in the range of 41 mm to 94 mm. The fecundity of spiny lobster was in the range of 762-182,006 eggs with the size at onset of spawning at an average carapace length is 63.10 mm. The spawning pattern of this spiny lobster a partial spawner. Female spiny lobsters below the size at onset of spawning are still catch in the west coast waters of Lampung Province. The peak of the spiny lobster spawning season occurs in November-December and the highest recruitment potential in February-April and August-October.
Keyword: Biologi reproduksi, Fekunditas, Gonad, Lobster pasir, Kabupaten Pesisir Barat, Fecundity, Gonad, Reproductive biology, Spiny lobster, Pesisir Barat Regency

Judul: Dinamika Populasi Lobster Pasir (Panulirus homarus) Dan Lobster Batu (Panulirus penicillatus) Di Perairan Selatan Jawa Barat
Abstrak: Lobster merupakan komoditas penting baik impor maupun ekspor. Permintaan pasar yang tinggi menyebabkan laju penangkapan tinggi sehingga mempengaruhi penurunan populasi. Penelitian ini bertujuan mengkaji status populasi lobster di perairan Selatan Jawa Barat berdasarkan pendugaan parameter dinamika populasi. Pengambilan sampel menggunakan metode penarikan contoh acak sederhana selama bulan Februari hingga Juni 2023. Ukuran panjang karapas lobster berkisar 30-182 mm dengan pola pertumbuhan allometrik negatif. Rekruitmen terjadi sepanjang tahun dengan satu puncak. Ukuran pertama kali tertangkap (Lc50) lobster pasir jantan pada panjang karapas 46,36 mm dan betina pada 49,65 mm, lobster batu jantan pada panjang karapas 50,69 mm dan betina pada 58,82 mm. Ukuran pertama kali mengerami telur (Lr50) lobster pasir betina pada panjang karapas 69,95 mm dan lobster batu betina pada 79,94 mm. Laju eksploitasi lobster betina termasuk kategori optimum dan jantan termasuk kategori overexploited. Rasio potensi pemijahan (SPR) lobster pasir dan batu betina berturut-turut sebesar 12% dan 4% yang mengindikasikan bahwa sumberdaya lobster telah mengalami overfishing., Lobster is an important commodity for both import and export. High market demand causes high capture rates that affect population decline. This study aims to assess the status of the lobster population in the southern waters of West Java based on the estimation of population dynamics parameters. Sampling used a simple random sampling method from February to June 2023. Lobster carapace length ranged from 30-182 mm with a negative allometric growth pattern. Recruitment occurred throughout the year with one peak. First caught size (Lc50) of male sand lobster at 46.36 mm carapace length and female at 49.65 mm, male rock lobster at 50.69 mm carapace length and female at 58.82 mm. The size of the first incubating egg (Lr50) of female sand lobster at 69.95 mm carapace length and female rock lobster at 79.94 mm. The exploitation rate of female lobsters is in the optimum category and males are in the overexploited category. The spawning potential ratios (SPR) of female sand and rock lobsters were 12% and 4%, respectively, indicating that the lobster resource has been overfishing.
Keyword: population dynamics, pronghorn spiny lobster, scalloped spiny lobster, Southern waters of West Java, sustainable

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
Keyword: