Judul: Rehabilitasi Mangrove di Pulau Nipah Berbasis Ekosistem Terpadu
Abstrak: Pulau Nipah merupakan unit ekosistem pulau kecil dan merupakan pulau terluar Negara Republik Indonesia yang berbatasan dengan Negara Singapura. Memperhatikan kondisi pulau Nipah dan potensi sumberdaya yang terkandung di dalamnya, maka perlu pengkajian karakteristik sumberdaya, kesesuaian penggunaan dan upaya pelestariannya termasuk upaya rehabilitasi mangrove. Pengkajian karakteristik lingkungan dilakukan dengan pengumpulan data primer ekosistem terumbu karang, padang lamun, komunitas mangrove, sifat fisik kimia air, hidro-oseanografi, serta kondisi sosial ekonomi masyarakat sekitar. Analisis SWOT dan analisis spasial dilakukan untuk mengetahui kesesuaian penggunaan sumberdaya pulau Nipah dan penentuan site/lokasi rehabilitasi mangrove. Sedangkan uji statistika dilakukan untuk mengetahui kesesuaian jenis tumbuhan mangrove, media tanam dan desain konstruksi rehabilitasi mangrove. Hasil penelitian ini menunjukan bahwa terdapat tumbuhan jenis Perepat (Sonneratia alba), Api-api (Avicennia marina) dan Bakau (Rhizophora stylosa) bisa ditanam pada lokasi yang direncanakan, namun demikian jenis perepat dan api-api diperkirakan merupakan jenis yang paling memiliki vigourness (tahan hingga menjadi tanaman dewasa), sedangkan desain konstruksi rehabilitasi perlu menggunakan media tanah Alluvial dan Podsolik diurug dengan ketinggian optimal adalah pada level yang setara dengan ketinggian teras setinggi 80-120 cm dari benchmark (0 cm terhadap benchmark = 1,49 m dpl) atau ketinggian 2,29-2,69 m dpl dengan pembangunan tanggul masif (beton) di bagian Utara dan tanggul batu belah di bagian Barat lokasi rehabilitasi mangrove seluas 11.7 ha. Jenis lamun, memiliki potensi keanekaragaman yang cukup rendah, dan terumbu karang memiliki keanekaragaman jenis yang cukup sedikit, namun demikian menyebar di sekitar pulau cukup baik. Untuk mendukung rehabilitasi mangrove di pulau Nipah, peran serta masyarakat secara aktif sangat diperlukan dengan tetap mempersiapkan sistem kelembagaannya.
Keyword: rehabilitation, mangrove, coastal resources, islet

Judul: Effectiveness of mangrove rehabilitation on pramuka island, seribu archipelago.
Abstrak: Mangrove ecosystem damage is generally caused by human activities, although it is undeniable, nature also has a considerable role. The damage will cause a reduction or even disappearance of system functions and benefits of mangrove for the community and the surrounding environment. To restore the damaged mangrove, it is necessary to attempt rehabilitation through mangrove management on Pramuka Island, Seribu Archipelago. The purpose of this study was (1) to examine the factors that determine the success of the rehabilitation of mangrove ecosystems on Pramuka Island, Seribu Archipelago, (2) to assess the effectiveness of the rehabilitation of mangrove ecosystems and the factors supporting the success and failure on Pamuka Island, Seribu Archipelago, and (3) to arrange the recommendations to improve the effectiveness of the rehabilitation of mangrove ecosystems on Pramuka Island, Seribu Archipelago. Assessment of mangrove rehabilitation success rate on Pramuka Island was done by analyzing several indicators of using an effectiveness index with taking into account also the environmental parameters of water quality such as temperature, flow velocity, salinity, pH, DO, TSS, nitrate, potassium, BOD5. Indicators of effectiveness of mangrove include eco-biologi indicators of mangrove rehabilitation that includes survival, growth and percent cover; and social indicators that include public participation and public perception. Results of this study showed that the majority of mangroves on Pramuka Island are the saplings, while for trees and seedlings only a small fraction. All existing mangrove rehabilitation was the result of the different planting years, only two trees ware considered a pre-existing natural mangrove long ago. Based on the measurement results, mangrove rehabilitation on Pramuka Island had a relative cover between 0.03 to 2.82%; growth of 13.33 to 32.50 cm/yr; and survival rate of 3.02 to 67.36%. Environmental conditions in the area of rehabilitation of mangrove waters are shallow water reef around the island stretches to a distance of about 500 m from the shoreline and the water quality is suitable for mangroves. Values of water quality measurements include temperature from 31.7 to 35 °C; flow velocity 0.1-0.3 m/s; TSS 4-16 mg/l; pH 7.54 to 8.20; salinity 25-28 psu; DO from 7.6 to 9.4 mg/l; nitrate from 0.039 to 0.156 mg/l; orthophosphate 0.002 to 0.283 mg/l; potassium 0.272 to 0.698; and BOD5 from 2.00 to 4.60 mg/l. Based on social conditions, all the people (100%) know about mangroves, both the function and existence. 60% of people also know that the mangrove on Pramuka Island is managed by TNKpS. In addition, people also take a role and participate in themanagement of the mangrove. Approximately 80% of respondents said had been involved in management efforts, including by contributing to maintain, not destroy the existence of mangroves and mangrove occasional cleaning of garbage. Community involvement is in line with the perceived benefits. 80% of vii respondents said that the mangroves are considered to lessen the blow of the waves, erosion and add coolness on the beach. Community involvement in management efforts can be improved if people know and can take advantage of direct utilization of mangrove like to candied fruit, wood utilization, etc.. So far there is no direct use
Keyword: mangrove ecosystem, TNKpS, ehabilitation, effectiveness

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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