Judul: Sponge Biodiversity Study Using DNA Metabarcoding in Dampier Strait, Raja Ampat Island, West Papua
Abstrak: Kepulauan Raja Ampat memiliki kawasan konservasi, salah satunya adalah Selat Dampier. Spons merupakan invertebrata laut dari filum Porifera dengan rongga dan struktur tubuhnya sederhana, serta memiliki kemampuan filter feeder. Tujuan dari penelitian ini adalah mengidentifikasi spons menggunakan DNA Metabarcoding di Selat Dampier. Metode DNA Metabarcoding adalah pendekatan molekuler yang berasal dari satu gabungan sampel melalui proses ekstraksi seluruh DNA dari sampel tertentu sehingga didapatkan taksonomi spesies. Metode yang dilakukan adalah pengambilan sampel, ekstraksi DNA, amplifikasi DNA, sekuensing DNA, identifikasi spesies, analisis sekuens, serta rekonstruksi pohon filogenetik. Terdapat 13 spesies spons yang berhasil diidentifikasi berdasarkan similarity dan query cover. Komposisi genus tertinggi adalah Callyspongia dan Pseudoceratina. Spons memiliki kandungan bioaktif yang digunakan sebagai antibakteri, antimikrobial, antikanker, antiparasit, serta antibiotik. Rekonstruksi pohon filogenetik untuk melihat tingkat kekerabatan spesies spons dengan model Kimura 2-parameter, serta pendekatan Neighbor Joining dan Maximum Likelihood, The Raja Ampat Islands have conservation areas, one of which is the Dampier Strait. Sponges are marine invertebrates from the phylum Porifera with simple body cavities and structures, and have filter feeder capabilities. The aim of this study is to identify sponsors using DNA Metabarcoding in the Dampier Strait. The DNA Metabarcoding method is a molecular approach that originates from a combined sample through the process of extracting all of the DNA from a particular sample in order to obtain a species taxonomy. The methods used were sampling, DNA extraction, DNA amplification, DNA sequencing, species identification, sequence analysis, and phylogenetic tree reconstruction. There are 13 species of sponges that have been identified based on similarity and query cover. The highest genus composition being Callyspongia and Pseudoceratina. Sponges contain bioactive compounds that are used as antibacterial, antimicrobial, anticancer, antiparasitic, and antibiotics. Reconstruction of phylogenetic trees to see the degree of kinship of sponge species with Kimura 2-parameter model, as well as the Neighbor Joining and Maximum Likelihood approaches.
Keyword: Dampier strait, DNA Metabarcoding, Phylogenetics, Sponge

Judul: Abundance of Sponges on Reef Ecosystems in Dampier Strait, Raja Ampat
Abstrak: Selat Dampier merupakan salah kawasan konservasi perairan Raja Ampat, bagian coral triangle. Kondisi terumbu karang di Selat Dampier termasuk dalam kondisi yang baik. Spons termasuk filum porifera yang bersifat sessile dan filter feeder. Komunitas spons dapat menjadi salah satu bioindikator. Secara ekologis, spons merupakan salah satu biota penyusun ekosistes terumbu karang. Tujuan dari penelitian ini adalah mengetahui kelimpahan spons yang berada di Selat Dampier dengan menggunakan metode Underwater Photo Transect (UPT). Kondisi terumbu karang pada Selat Dampier tergolong cukup baik (30,29%) dan didominasi oleh tutupan karang keras. Hasil identifikasi spons didapatkan 506 individu dari 93 spesies, 66 genus, 41 famili, dan tiga kelas. Demospongia merupakan kelas paling sering dijumpai. Famili yang paling banyak ditemukan adalah Chalinidae dengan total individu 56. Selain itu, Chalinidae merupakan famili dengan spesies terbanyak, yaitu delapan spesies. Aaptos suberitiodes adalah spesies dengan total individu terbanyak, yaitu 35 individu. Hasil correspondence analysis menunjukkan adanya asosiasi antara komunitas spons dengan tutupan karang keras dan rubble., Dampier Strait is one of the water areas of Raja Ampat, included the coral triangel. The condition of coral reefs in Dampier Strait is good condition. Sponges are phylum Porifera which are sessile and filter feeder. Sponge communities can be one of the bioindicator. Ecologically, sponges are one of the constituent biota of reef ecosystems. The objective of this study is determine the abundance of sponges in Dampier Strait using the Underwater Photo Transect (UPT) method. The condition of coral reefs in the Dampier Strait is quite good (30,29%) and dominated by hard corals. The results of sponge identification are 506 individuals from 93 species, 66 genera, 41 families, and three classes. Demospongia are the classes most often found. The most common family found is Chalinidae with a total of 56 individuals. Moreover, Chalinidae is the family with the most species, which is eight species.Aaptos suberitiodes is the species with the largest total number of individuals studied, 35 individuals. The results of correspondence analysis show an association between sponge communities with hard coral and rubble cover.
Keyword: abundance, Dampier Strait, coral reefs, sponge

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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