Judul: Macrozoobenthos Community Structure in Seagrass Ecosystem in Tidung Island, Seribu Islands
Abstrak: Pulau Tidung terbagi menjadi dua gugusan pulau, yaitu Pulau Tidung Besar dipengaruhi aktivitas antropogenik, dan Pulau Tidung Kecil tidak dipengaruhi aktivitas antropogenik. Salah satu ekosistem di Pulau Tidung yang keberadaannya kurang diperhatikan ialah ekosistem lamun. Penelitian ini bertujuan menganalisis struktur komunitas makrozoobenthos pada ekosistem lamun di kedua pulau. Stasiun pengambilan contoh terdiri dari dua stasiun, yakni di Utara Tidung Besar dan di Utara Tidung Kecil dengan menggunakan metode garis transek. Analisis yang dilakukan meliputi kepadatan makrozoobenthos, indeks ekologi, dan keterkaitan makrozoobenthos dengan parameter pendukung. Makrozoobenthos yang ditemukan di Pulau Tidung terdiri dari 34 ordo, 57 famili, 76 genus didominasi oleh kelas Gastropoda. Rata-rata kepadatan makrozoobenthos pada masing-masing stasiun sebanyak 24 ind/m2 dan 20 ind/m2. Indeks ekologi menunjukkan bahwa makrozoobenthos berada dalam kondisi yang baik. Hasil PCA menunjukkan bahwa kepadatan makrozoobenthos memiliki hubungan yang kuat dengan suhu., Tidung Island has two islands, namely Tidung Besar Island which is affected by anthropogenic activities, and Tidung Kecil Island which is less affected by anthropogenic activities. One of the ecosystems in Tidung Island whose existence is less considered is seagrass ecosystem. This study aims to analyze the structure community of macrozoobenthos in seagrass ecosystems on both island. The sampling stations consisted of two stations, North of Tidung Besar and North of Tidung Kecil using the line transect method. The analysis included macrozoobenthos density, ecological index, and macrozoobenthos association with supporting parameters. Macrozoobenthos found in Tidung Island consisted of 34 orders, 57 families, 76 genus dominated by Gastropoda class. The average density of macrozoobenthos at each station was 24 ind/m2 and 20 ind/m2. Ecological index shows that macrozoobenthos are in good condition. PCA results showed that macrozoobenthos density had a strong relationship with temperature.
Keyword: water quality, seagrass, anthropogenic, gastropoda, gastropoda, macrozoobenthos

Judul: Macrozoobenthos Community Structure in the  Seagrass Ecosystem as an Indicator of Habitat Quality for Pramuka Island, Seribu  Islands
Abstrak: Aktivitas antropogenik di ekosistem lamun dapat menyebabkan pencemaran dan mempengaruhi biota di dalamnya, seperti makrozoobenthos dan lamun. Penelitian ini bertujuan untuk menganalisis struktur komunitas makrozoobenthos yang dikaitkan dengan kesehatan lamun, kualitas air dan substrat pada ekosistem lamun di Pulau Pramuka, Kepulauan Seribu. Metode yang digunakan yaitu analisis parameter kualitas air, kepadatan makrozoobenthos, indeks keanekaragaman, indeks keseragaman, indeks dominansi, tipe substrat, analisis komponen utama, dan analisis Spearman Rank. Makrozoobenthos yang diperoleh terdiri atas 6 kelas, yaitu Gastropoda, Bivalvia, Asteroidea, Malacostraca, Polychaeta, dan Echinoidea. Tipe substrat di Pulau Pramuka yaitu berpasir. Indeks keanekaragaman dan indeks keseragaman tergolong tinggi dan indeks dominansi tergolong rendah. Kualitas air tergolong masih baik dan masih di batas baku mutu air laut. Kepadatan lamun di Pulau Pramuka tergolong rendah atau rusak., Anthropogenic activities in seagrass ecosystems can cause pollution and affect the biota within them, such as macrozoobenthos and seagrass. This research aims to analyze the macrozoobenthos community structure which is associated with seagrass health, water and substrate quality in the seagrass ecosystem on Pramuka Island, Seribu Islands. The methods used are analysis of water quality parameters, macrozoobenthos density, diversity index, uniformity index, dominance index, substrate type, principal component analysis, and Spearman Rank analysis. The macrozoobenthos obtained consists of 6 classes, namely Gastropoda, Bivalvia, Asteroidea, Malacostraca, Polychaeta, and Echinoidea. The substrate type on Pramuka Island is sandy. The diversity index and uniformity index are relatively high and the dominance index is low. The water quality is still classified as good and still within the sea water quality standards. Seagrass density on Pramuka Island is classified as low or damaged.
Keyword: makrozoobentos, lamun, struktur komunitas, kepadatan, community structure, density, macrozoobenthos, seagrass

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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