Judul: Social Behavior of Langur Borneo (Presbytis chrysomelas ssp. cruciger) in Lupak Mawang Resort, Danau Sentarum National Park
Abstrak: Status kritis dan terbatasnya penelitian pada populasi langur borneo mendorong dilakukannya pengumpulan data bioekologi, salah satunya mengenai perilaku sosial. Penelitian ini bertujuan untuk mengidentifikasi perilaku sosial; menganalisis hirarki dan peranan sosial pada kelompok; serta mengidentifikasi interaksi sosial langur borneo dengan jenis primata lain. Penelitian dilaksanakan pada bulan Juli hingga Agustus 2021 di Resort Lupak Mawang, Taman Nasional Danau Sentarum. Pengumpulan data primer perilaku sosial langur borneo dilakukan dengan metode scan sampling dan pencatatan continuous recording. Langur borneo melakukan 66 kali perilaku sosial dengan durasi total 72 menit. Pada perilaku agonistik, vokalisasi, bermain, menelisik, dan seksual, masing-masing persentase frekuensi 48,48%; 39,39%; 10,61%; 1,52%; dan 0%. Lama penggunaan waktu secara berturut-turut sebesar 44,44%; 41,67%; 12,50%; 1,39%; dan 0%. Dominasi teridentifikasi melalui perilaku agonistik, vokalisasi, dan peranan dalam mengatur pergerakan kelompok. Interaksi sosial langur borneo dengan jenis primata lain didominasi oleh perilaku agonistik dan besar disebabkan oleh tumpang tindih habitat., The critical status and limited research on the langur borneo population has prompted the collection of bioecological data on of which is social behavior. This study aims to identify social behavior; analyze the group’s hierarchy and social roles; and identify the social interactions between langur borneo and other primate species. This data research was carried out from July to August 2021 in Lupak Mawang Resort, Danau Sentarum National Park. Primary data of langur borneo’s social behavior was collected by using scan sampling method and continuous recording. Langur borneo performed 66 times social behaviors with a total duration of 72 minutes. Each frequency percentage of agonistic, vocalization, playing, grooming, and sexual behaviors are 48.48%; 39.39%; 10.61%; 1.52%; and 0%. Time length succesively are 44,44%; 41.67%; 12.50%; 1.39%; and 0%. The dominance was identified through agonistic behavior, vocalizations, and role in regulating group movement. The social interaction between langur borneo and other primate species is dominated by agonistic behavior and most influenced by overlapping habitat.
Keyword: langur borneo, social behavior, social hierarchy, social interactions

Judul: Daily Activities and Forest Structure Usage by Langur Borneo in Lupak Mawang Resort Danau Sentarum National Park
Abstrak: Langur borneo merupakan primata endemik yang memiliki wilayah persebaran di Pulau Kalimantan dan masuk dalam kategori terancam punah dengan level kritis (critically endangered) menurut IUCN. Penelitian ini bertujuan untuk mengidentifikasi aktivitas harian langur dan mengidentifikasi penggunaan ruang oleh langur borneo. Penelitian dilaksanakan pada bulan Juli - Agustus 2021 yang berlokasi di Bukit Semujan, Resort Lupak Mawang – TN Danau Sentarum. Aktivitas harian diamati dengan menggunakan metode scan sampling sedangkan pola penggunaan ruang diidentifikasi dengan analisis vegetasi. Hasil penelitian menunjukkan aktivitas harian yang memiliki persentase terbesar berdasarkan pembagian waktu dan frekuensi perjumpaan yaitu aktivitas sosial yang dilakukan pada sore hari dengan persentase sebesar 73.68% dan 72.22%. Strata C dengan ketinggian 4-20 m dengan persentase sebesar 70.49% merupakan kategori strata yang paling sering digunakan oleh Langur borneo dalam melakukan seluruh aktivitasnya. Hasil analisis vegetasi di hutan primer dan sekunder menunjukkan bahwa pohon tekam padi (Polyalthia insignis) dan pohon kelangsau (Dryobalanops lanceolata) mempunyai indeks nilai penting tertinggi yaitu masing-masing sebesar 50.00% dan 115.05%., Langur borneo is an endemic species that occurred only in Kalimantan and is categorized by the IUCN as a critically endangered species. This research aim is to identify the daily activities and forest structure usage by langur borneo. This research was conducted from July to August 2021 at Bukit Semujan, Lupak Mawang Resort, Danau Sentarum National Park. The daily activities were observed using the scan sampling method, meanwhile for forest structure usage were using vegetation analysis. Results show that daily activities with the largest percentage based on time usage and frequency are the social activity which was carried out in the afternoon with each percentage of 73,68% and 72,22%. Strata C (4-20 meters) with a percentage of 70.49% be the most often used strata category by Langur borneo to carry out their activities. Result of the vegetation analysis in primary and secondary forest respectively shows that tekam padi (Polyathia insignis) and Kelangsau (Dryobalanops lanceolata) trees had the highest important value index, with each percentage of 50.003% and 115.04%.
Keyword: daily activities, forest structure use, langur borneo

Judul: Hydroxyapatite-Chitosan Composite Coating on Stainless Steel 316 to Improve Corrosion Resistance
Abstrak: Metals that were used in bone implantation should have good corrosion resistance that were not easily corroded when implanted into the body. Metal corrosion resistance of stainless steel 316 can be enhanced through the metal coating by hydroxyapatite-chitosan composite with composition ratio of hydroxyapatite (gram) and chitosan 3% (mL) 0.2:0, 0.2:0.1, 0.2:0.5, 0.2:1.0, and 0.2:1.5. Besides improving the corrosion resistance of metal, the presence of chitosan also maintain the position of hydroxyapatite on metal surfaces. Corrosion resistance increases with increasing amount of chitosan added and the best composition of hydroxyapatite-chitosan composite was 0.2:1.0.
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