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: 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.
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Judul: Pembuatan Film Tipis Cu2ZnSnS4 sebagai Lapisan Penyerap Cahaya pada Sel Surya Menggunakan Metode Elektrodeposisi
Abstrak: Thin film of Cu2ZnSnS4 (CZTS) is an alternative semiconductor used as light absorber layer on solar cell. CZTS can replace silicon that commonly used as commercial semiconductor. The advantage of using CZTS as absorber layer is due to the abundance of its chemical composer on earth, and its high value of absorption coefficient. The absorber layer was made by using electrodeposition method on ITO glass substrates. The films were deposited at room temperature using potentiostatic mode with a potential of –1.05 V for 30, 45, and 60 minutes. After that, the films were annealed at two different temperatures, 180 ºC and 500 °C, for 45 minutes in N2/H2S atmosphere. Based on X-ray diffraction analysis, the polycrystalline thin film obtained fall into kesterite crystal phase. This type of crystal was obtained when the CZTS was annealed at 500 °C in H2S/N2 atmosphere. The value of optical band gap energy for the CZTS thin film was 2.2 eV with the film thickness about 1.228–6.366 μm. The sample of CZTS with electrodeposition time of 45 minutes and annealing temperature of 500 °C showed the best result and in conformity with absorber layers criteria for solar cells.
Keyword: semiconductor, ITO glass, CZTS thin film, electrodeposition