Judul: Accumulation of Heavy Metals Lead and Cadmium in Leaves and Roots of Avicennia marina in Muara Angke Mangrove Protected Forest
Abstrak: Hutan Lindung Mangrove Muara Angke (HLMMA) di pesisir utara Jakarta merupakan satu-satunya hutan lindung yang berada di wilayah DKI Jakarta. Namun, perairan Jakarta telah tercemar logam berat diantaranya kadmium (Cd) dan timbal (Pb), yang dapat membahayakan kesehatan makhluk hidup. Penelitian yang dilakukan pada Juni – Agustus 2022 ini bertujuan untuk mengetahui nilai kandungan logam berat Cd dan Pb pada organ daun dan akar Avicennia marina, serta mengetahui pengaruh perbedaan jarak dari garis pantai terhadap kandungan logam di HLMMA. Analisis kandungan logam berat dilakukan dengan metode Spektrofotometri Serapan Atom (SSA). Hasil penelitian menunjukkan bahwa kandungan Pb lebih besar daripada kandungan Cd, baik pada daun maupun pada akar. Akumulasi Cd dan Pb pada daun lebih tinggi daripada akar, dengan nilai Cd tertinggi sebesar 0,081 ppm dan nilai Pb tertinggi sebesar 4,070 ppm. Nilai Cd dan Pb yang terakumulasi pada daun dan akar pohon A. marina di lokasi ini sudah melampaui baku mutu air laut untuk biota laut. Tidak ada perbedaan signifikan antara kandungan logam pada daun dan akar dengan jarak yang berbeda dari garis pantai maupun kandungan logam pada daun dan akar dengan jarak yang sama dari garis pantai. Adapun nilai faktor translokasi logam berat > 1, baik untuk logam Cd maupun Pb., Muara Angke Mangrove Protection Forest (HAMPF) on the north coast of Jakarta is the only protected forest in DKI Jakarta region. However, Jakarta waters have been polluted by heavy metals including cadmium (Cd) and lead (Pb) which can endanger the health of living beings. This research conducted in June – August 2022, aims to determine concentration of Cd and Pb in leaves and roots of Avicennia marina, and to determine effect of distance differences from shoreline on metal concentration in HAMPF. Heavy metal was analyzed with Atomic Absorption Spectrophotometry (AAS) method. The results showed that Pb concentration was greater than Cd, both in leaves and roots. Cd and Pb accumulation in leaves was higher than in roots, with the highest value are 0.081 ppm (Cd) and 4.070 ppm (Pb). The Cd and Pb concentration of A. marina trees in this location have exceeded the sea water quality standard for marine biota. There was no significant differences between metal concentration in leaves and roots at different distances, nor metal concentration between leaves and roots at the same distance. Translocation factor is > 1, both for Cd and Pb metal concentrations.
Keyword: cadmium, heavy metals, Avicennia marina, Muara Angke, plumbum

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
Keyword: 

Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
Keyword: