Judul: Akumulasi Logam Berat Timbal (Pb) dan Cadmium (Cd) pada Pohon Mangrove (Avicennia marina) di Perairan Karangsong, Indramayu.
Abstrak: Mangroves are known to have the ability to absorb and store heavy metals and other contaminants in the body tissues such as leaf and root. This research was carried out in January-March 2013 with the aim to find out the levels of heavy metals Lead (Pb) and Cadmium (Cd) in root and leaf of Avicennia marina, as well as sediments in Karangsong waters, Indramayu. Sampling a root, leave, and sediments was repeated 3 times each. The results showed that levels of Pb in Avicennia marina already passed over the limit of tolerance concentration for plants, whereas the levels of Cd was below detection limit Based on the results, it can be seen Avicennia marina has a low level of bioconcentration factor (BCF), it means that Avicennia marina has a low capability to accumulate heavy metals. Meanwhile the value of translocation factor (TF) is high, mean Avicennia marina has high mobilization from roots to leaves. Based on the findings, it is strongly recommended to control pollutants falling into the aquatic environment, and to enhance mangrove rehabilitation program for ecological and economical function
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Judul: Akumulasi Logam Berat Tembaga (Cu) dan Timbal (Pb) pada Pohon Mangrove (Rhizopora mucronata) di Perairan Karangsong, Indramayu.
Abstrak: Mangrove has many economical and ecological functions, one of its abilities is to absorb, transport and store substances including toxic materials. This research aim is to analyze the concentration of Cu and Pb in root, leave and substrat of mangrove Rhizopora mucronata and its bioaccumulation level. The concentration of Cu found in sediment exceed standar quality by RNO, which means the sediment has been contaminated by Cu. The content of Cu in the roots and leaves of mangrove is greater than Pb, so does the highest level of bioconcentration factor (BCF) was reached by BCF Pb in root at 1.3116 while BCF Cu in roots at 0,5609. This indicates that the potention of accumulation of roots is much higher than the leaves. The highest Translocation Factor (TF) was attained by Pb which is 0.4075 and the lowest is 0.3341 in Cu. Metal translocation from roots to leaves for essential metals (Cu) is lower than in non-essential metals (Pb), it shows that the mangrove use Cu for metabolic activity and growth. The ability of mangrove in accumulating this metals are still low in category according to Concentration Factor Index.
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Judul: Kajian frieze groups untuk klasifikasi dan konstruksi desain berdasarkan simetri pada pola
Abstrak: Frieze groups adalah konsep matematika untuk mengklasifikasikan desain pada dua dimensi permukaan yang berulang-ulang dalam satu arah berdasarkan simetri pada pola. Frieze groups merupakan grup yang mempertahankan bentuk pola. Pergerakan bentuk pola terdiri dari translasi, refleksi dan rotasi 180o. Tujuan dari karya ilmiah ini adalah mengkaji sifat Frieze group, mengkaji penggunaan Frieze group dalam mengklasifikasikan simetri pada pola dan mengkonstruksi pola dengan menggunakan software tesselmania. Hasil yang telah diperoleh, bahwa jenis Frieze groups merupakan subgroup dari grup pergerakan pola. Selain itu dapat dilihat dari sifat isomorfik berbagai jenis Frieze groups. Untuk mengkonstruksi sebuah bentuk pola dapat menggunakan salah satu software untuk membentuk sebuah pola bidang datar (dua dimensi) yaitu tesselmania.
Keyword: Frieze groups, Simetri, Pola