Judul: Seagrass Community Status in East Coast of Bintan Island, Riau Islands (2015-2019).
Abstrak: Pesisir timur Kabupaten Bintan memiliki padang lamun dengan keanekaragaman tinggi. Maka perlu upaya pelestarian secara berkelanjutan untuk menjaga kondisi padang lamun Bintan. Tujuan penelitian ini adalah: 1) mengetahui status terkini (2019) dan kecenderungan kondisi padang lamun di pesisir Bintan Timur (2015 – 2019); 2) menggambarkan tipologi dan struktur komunitas padang lamun di pesisir timur Kabupaten Bintan. Penelitian dilakukan di 8 stasiun. Pengolahan data dilakukan dengan menghitung tutupan, dominansi, Uji Anova, Uji t-test, dan analisis clustering. Padang lamun di Kabupaten Bintan tahun 2019 termasuk kurang sehat dengan kondisi menurun pada tahun 2015-2017, serta peluang pemulihan sebesar 23,85% pada dua tahun berikutnya. Terdapat 9 jenis lamun di lokasi penelitian selama 2015-2019, yaitu E. acoroides, T. hemprichii, C. serrulata, C. rotundata, H. uninervis, H. pinifolia, H. ovalis, S. isoetifolium, dan T. ciliatum. Bintan memiliki dua jenis padang lamun, yaitu padang lamun didominasi spesies suksesif (ST 1) dan padang lamun campuran (ST 2, ST 3, ST 5, ST 6, ST 7, dan ST 8)., The east coast of Bintan Regency has a high diversity of seagrass beds. It is necessary to preserve in a sustainable manner to mantain the condition of Bintan’s seagrass beds. The objective of this research was: 1) to find out the current status (2019) and trends in seagrass beds on the coast of East Bintan (2015-2019); 2) to describe the typology and structure of seagrass communities on the east coast of Bintan. The research was conducted at 8 stations. Data processing was performed by calculating cover, dominance, ANOVA test, t-test, and clustering analysis. Seagrass beds in Bintan Regency in 2019 categorized as unhealthy with declining conditions in 2015-2017, and a chance 28,85% of recovery in the next two years. There were 9 species of seagrass observed from 2015-2019, namely E. acoroides, T. hemprichii, C. serrulata, C. rotundata, H. uninervis, H. pinifolia, H. ovalis, S. isoetifolium, and T. ciliatum. Bintan has two types of seagrass beds dominated by successive species (ST 4) and mixed seagrass beds (ST 1, ST 2, ST 3, ST 5, ST 6, ST 7, and ST 8).
Keyword: Bintan, Lamun, Status, Tipologi, Tutupan, Bintan, cover, seagrass, status, typology

Judul: Condition of Seagrass Beds Pengudang Village Bintan during the North West Monsoon on January 2018
Abstrak: Angin Muson Barat Daya atau lebih dikenal sebagai angin utara merupakan angin musim di Bintan yang dicirikan oleh kondisi cuaca berangin kencang dan curah hujan tinggi serta perairan laut bergelombang tinggi dan kecepatan arus permukaan yang kuat. Kondisi tersebut berdampak yang terhadap padang lamun, khususnya di Desa Pengudang yang menghadap langsung arah datangnya angin musim. Penelitian ini dilakukan di 3 Stasiun, dengan 3 tahap kegiatan, yaitu: 1) pengamatan padang lamun dengan transek kuadran untuk pengukuran tutupan dan kerapatan jenis, serta analisis kondisi lamun, 2) Pengukuran parameter fisik pantai dan perairan serta pengambilan sampel sedimen di padang lamun, serta 3) Pengumpulan data sekunder dan reanalisis data untuk menggambarkan kondisi oseanografi di sekitar Pulau Bintan yang dibandingkan dengan survey lapang. Hasil penelitian mendapati kondisi padang lamun yang tergolong baik dengan ditemukannya 7 spesies dengan kisaran tutupan 47%-67%. Keragaman lamun tertinggi ada di Stasiun 3, berupa ditemukan spesies C. serrulata (Cs) dan C. rotundata (Cr). Substrat perairan didominasi oleh pasir halus dan pasir sangat halus. Pesisir Desa Pengudang memiliki kategori pantai datar yang berisiko lamun terekspos ke udara terbuka saat kondisi perairan surut. Ketinggian gelombang dan kecepatan arus permukaan pada musim utara lebih tinggi dibanding ketiga periode musim lainnya. Berdasarkan karakteristik oseanografi perairan dan sedimen, perairan Desa Pengudang merupakan habitat yang sesuai bagi padang lamun yang memberi perlindungan pantai terhadap dampak erosi saat musim utara., The north west monsoon or better known as the north wind in Bintan is a seasonal wind with extreme weather and rain, also high waves and stronger surface currents. These conditions have a considerable impacts on seagrass bed conditions in Pengudang Village, which located in the windward section of Bintan Island. Observation and sampling were conducted in 3 stations, with 3 main activities, namely: 1) seagrass bed observation using quadrant transects to measure species coverage, shoot density, and qualitative analysis of seagrass bed conditions. 2) Field measurement of several physical oceanography parameters and sampling of seagrass sediment, and 3) Collation and re-analysis of secondary data set to describe general oceanographic features of Bintan waters and cross-validated with field observation results. Seagrass condition is considered good with 7 species observed and range of coverage 47 -67%. The highest seagrass diversity was observed at Station 3, with additional two species of C. serrulata (Cs) and C. rotundata (Cr). Seagrass sediment is dominated by fine sand and very fine sand. The coasts of Pengudang Village featured flat elevation from the beach to seagrass beds, thus aerial exposure of seagrass shoots will be risky during low tide. Wave height and surface currents during the northwest monsoon is higher than other seasons. Referring to oceanographic condition of coastal waters and sediment, the coasts of Pengudang Village provide suitable habitats for seagrass beds protecting the beach from erosion during northwest monsoon.
Keyword: Angin Utara, Bintan, Desa Pengudang, Gelombang, Oseanografi, Padang Lamun

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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