Judul: Keanekaragaman Ketam di Sungai yang Berhulu dari Gunung Salak, Bogor, Jawa Barat
Abstrak: Freshwater crab is decapods crustacean of infraorder Brachyura. Freshwater crabs are one of the most ecologically important macro-invertebrate groups in tropical inland waters. The objective of this research was to assess the diversity of freshwater crabs in rivers of mount Salak, Bogor, West Java. Freshwater crabs were taken from eleven sites. Identification based on morphological characteristic and verified by DNA barcode. Three species of freshwater crabs were found Salak Mountain, that are Geosesarma sp., Parathelphusa bogoriensis and Parathelphusa convexa. Those three species were commonly found in Java. Geosesarma sp. can be found around rocks on river banks. Parathelphusa bogoriensis can be found at the brook or under rocks. Parathelphusa convexa can be found on river banks.
Keyword: 

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: Elektrodeposisi Film Tipis Semikonduktor Cu2ZnSnS4 (CZTS) pada Substrat Kaca ITO
Abstrak: Semiconductor Cu2ZnSnS4 (CZTS) thin film that can be used as absorber layers on solar cell module was made via electrodeposition method. CZTS thin film was electrodeposited on the surface of a silicate glass coated with a thin layer of indium tin oxide (ITO). Deposition process was done using potentiostatic mode at room temperature with a potential of 1.05 V for 30, 45, and 60 minutes, followed with annealing the film at 2 different temperatures, 500 ºC using furnace and 180 ºC using hot plate, both treatments for 45 minutes in N2/H2S atmosphere. The X-ray difractograms were analyzed using Match 2 program and showed that the CZTS thin films had kesterit crystalline structure, with a low percentage of CZTS phase. The thin film also contained secondary phases such as Cu2S, ZnS, and SnS. The obtained CZTS thin films had a thickness between 1.039 and 1.676 μm. Absorption study showed that the band gap energy of CZTS thin films which was annealed using furnace ranged from 1.50 to 1.52 eV, whereas that annealed using the hot plate was not observed. The band gap energy value showed that CZTS thin films can be used as sunlight absorber layers on solar cell. The formation of CZTS crystal film on this investigation was effectively performed using furnace annealing process at a temperature of 500 ºC with deposition time of 45 minutes.
Keyword: Thin film, Electrodeposition, Cu2ZnSnS4