Judul: Kondisi Ekologis dan Pengelolaan Mangrove di SPTN III, Taman Nasional Kepulauan Seribu
Abstrak: Efektivitas pengelolaan mangrove sangat bergantung pengetahuan tentang kondisi mangrove dan lingkungannya, yang dapat diketahui dari indeks kesehatan mangrove dan indeks kualitas lingkungan mangrove. Penelitian ini bertujuan mengkaji kondisi ekologis, kesehatan dan lingkungan mangrove di daerah SPTN III (Pulau Karya, Pulau Panggang, dan Pulau Pramuka) TNKS untuk merumuskan strategi pengelolaannya. Penelitian ini dilaksanakan pada bulan Februari 2020. Analisis ekologi yang dilakukan adalah indeks kesehatan mangrove dan indeks kualitas lingkungan mangrove. Kerapatan mangrove kategori anakan di seluruh pulau termasuk kategori sangat padat, sedangkan kategori pohon dan semai hanya ditemukan di beberapa tempat saja. Secara umum nilai kualitas lingkungan mangrove menunjukkan kualitas lingkungan mangrove yang tinggi (baik). Indeks kesehatan mangrove di ketiga pulau termasuk dalam kategori kesehatan mangrove rendah (buruk), meskipun di beberapa tempat ditemukan mangrove kategori pohon dengan kerapatan yang padat. Berdasarkan hasil tersebut perlu dilakukan rancangan strategi berupa replantasi dan pengelolaan berbasis zonasi di wilayah SPTN III., The effectiveness of mangrove management is highly dependent on the knowledge of the condition of mangrove and their environment, which are represented by the mangrove health index and the mangrove environmental quality index. This study aimed to analyze the ecological condition of mangroves in the SPTN III area (Karya Island, Panggang Island, and Pramuka Island) Seribu Islands National Park area to determine the management strategy. This research was conducted in February 2020. The analysis carried out were mangrove health and mangrove environmental quality. The Mangrove density in the sapling category throughout the island was very dense category, while the tree and seedling growth categories are only found in a few places. The value of the mangrove environmental quality indicate that the environmental quality of the mangroves in the three islands was in high category (good). The mangrove health index in the three islands in other hand was low category (bad), though in some places mangroves showed densed density. Based on these results, mangrove replantation is the strategy mostly recommended for SPTN III.
Keyword: kesehatan mangrove, kualitas lingkungan, replantasi

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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