Judul: The Occurrence of Brachyuran's Crab    Around The PLTU Plant in Probolinggo
Abstrak: Brachyuran are a diverse group that are crucial to the environment, yet vulnerable to higher temperatures in their habitat. Brachyuran diversity correlates with shorelines due to their life cycle that depends on the tidal wave and the seawater currents. Steam power plants, such as PLTU, release high-temperature water as a byproduct that could potentially alter the environment. This research was conducted using purposive sampling in Paiton, Probolinggo, at several sites around PLTU. The species were identified based on morphological features. Brachyurans found at three sites, Grinting Beach, Bohay Beach, and PLTU water outlet comprised 9 species and 66 individuals. The Species found include Gelasimus vocans, Metopograpsus messor, Ocypode ceratophthalmus, Mictyris longicarpus, Matuta victor, Macrophthalmus convexus, Macrophthalmus sp., Leptodius exaratus, Eriphia sebana, and Pilumnus vespertilio. Brachyuran diversity tends to differ at each location due to environmental variables that could be advantageous and disadvantageous to different brachyuran species., Brachyuran are a diverse group that are crucial to the environment, yet vulnerable to higher temperatures in their habitat. Brachyuran diversity correlates with shorelines due to their life cycle that depends on the tidal wave and the seawater currents. Steam power plants, such as PLTU, release high-temperature water as a byproduct that could potentially alter the environment. This research was conducted using purposive sampling in Paiton, Probolinggo, at several sites around PLTU. The species were identified based on morphological features. Brachyurans found at three sites, Grinting Beach, Bohay Beach, and PLTU water outlet comprised 9 species and 66 individuals. The Species found include Gelasimus vocans, Metopograpsus messor, Ocypode ceratophthalmus, Mictyris longicarpus, Matuta victor, Macrophthalmus convexus, Macrophthalmus sp., Leptodius exaratus, Eriphia sebana, and Pilumnus vespertilio. Brachyuran diversity tends to differ at each location due to environmental variables that could be advantageous and disadvantageous to different brachyuran species.
Keyword: morphology, shoreline, diversity, tidal wave, Paiton

Judul: The diversity of freshwater crab (Crustacea Decapoda: Brachyura) in the Regencies of Batanghari and Sorolangun, Jambi Province
Abstrak: Freshwater crabs are members of the order Decapoda, sub order Brachyura. They can be found in all freshwater bodies. They can also adapt to semi-terrestrial and terrestrial environments. The diversity of freshwater crabs has declined due to habitat changes. Jambi province is an area with high deforestation rate compared to other Asian regions. The deforestation causes habitat fragmentation which alters the biota composition, both terrestrial and aquatic biota. The aims of this study were to study the diversity of freshwater crab in the Regencies of Batanghari and Sorolangun of Jambi in several habitats type. The study was conducted in rubber plantations, oil palm plantations, community forests and secondary forests located at the Regencies of Batanghari and Sorolangun. The specimens were collected by using hand net and fish trap which were preserved in 70% alcohol. The environmental factors observed were altitude (m), brightness (m), velocity (m/second), temperature (°C), depth (m), width (m), pH and substrate type. In Batanghari and Sorolangun Regency, was found 5 species of freshwater crabs that consisted of Parathelphusa tridentata, P. batamensis, P. maindroni, P. maculata and Geosesarma sp. through morphological identification. Based on mitochondrial COI gene analysis, P. batemensis and P. maindroni have nucleotide difference 1.45% (8 nt). In Batanghari Regency, the environmental factors affecting the distribution of P. batamensis were pH, temperature and width of the river, while the distribution of P. maculata, P. tridentata, and Geosesarma sp was affected only by depth; and P. maindroni was altitude. In Sorolangun Regency, the environmental factors affecting the distribution of Geosesarma sp and P. maculata were velocity, the distribution of P. batamensis and P. tridentata was affected by depth and brightness, while the distribution of P. maindroni was influenced by altitude. The highest freshwater crab diversity was found in community forest of both regencies. The lowest freshwater crab diversity was found in oil palm plantation habitat in Sorolangun Regency. The community structure of freshwater crab in Batanghari and Sorolangun Regencies was different in each habitat. Parathelphusa batamensis was found in all habitat types in both regencies. The results of the Multiple Comparisons test showed that In Batanghari Regency there were differences in number of individual crab among community forest and oil palm plantation (P<0.01), as well as at community forest and rubber plantation. In Sorolangun Regency, the number individual of crabs among rubber plantation and secondary forest (SF) were significantly different (P<0.001).
Keyword: Brachyura, COI, Decapoda, Geosesarma, Parathelphusa, Jambi.

Judul: Konstruksi aritmetika kurva eliptik F(2m) supersingular dan non-supersingular untuk skema kunci publik ElGamal
Abstrak: Algoritme ElGamal adalah salah satu algoritme kunci publik dengan aritmetik modular p yang mempunyai struktur grip siklik Z(p). Tingkat keanaman algoritme ini terletak pada pemecahan masalah logaritme diskret dari Z(p). Akan tetapi, tingkat keamanan tadi tahun ke tahun semakin menurun yang disebabkan kemampuan pemecahan algoritme diskret semakin meningkat. Untuk memenuhi tingkat keamanan yang memadai dibutuhkan p yang cukup besar yang menyebabkan proses enkripsi dan dekripsi menjadi lambat.
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