Judul: Variasi Geografis dan Lingkungan dalam Anggaran Aktivitas dan Kebiasaan Makan Orangutan di Sumatera
Abstrak: Food availability is a major determinant of primate activity, home range use, group size, and population parameters. Food environments of captive animals, for example, would much better than the wild populations. There is a regional variation in the wild's food environments, mainly due to physical conditions and forest structure. This study analyzed the impact of differences in geographic and environmental variables and forest types on the behavioral and social aspects of orangutans in Sumatra. This study also compared the orangutans' activity between captive and wild conditions. Altitude, mean temperature, and annual rainfall of six wild orangutans in Sumatra study sites ranged 0 - 2067 m, 18 - 31 oC, and 1125 - 3967 mm, respectively. There were no significant differences in activity budgets, dietary habits, home ranges, daily travel distances, and group composition of the orangutans among forest types. None of the geographical and environmental variables were correlated with the behavioral and social aspects. Furthermore, there were no significant differences in orangutan activities between wild and captive, except feeding activity. Besides the small number of study sites, the lack of variation in behavioral and social aspects implied the orangutans' conservative nature., Ketersediaan makanan merupakan penentu utama dari aktivitas primata, penggunaan wilayah jelajah, ukuran kelompok, dan parameter populasi. Lingkungan makanan hewan penangkaran, misalnya, jauh lebih baik daripada populasi liar. Bahkan pada populasi liar, terdapat variasi regional dalam lingkungan makanan, terutama karena kondisi fisik dan struktur hutan. Studi ini menganalisis dampak perbedaan variabel geografis dan lingkungan, dan tipe hutan terhadap aspek perilaku dan sosial orangutan. Studi ini juga membandingkan aktivitas orangutan antara kondisi penangkaran dan liar. Ketinggian, suhu rata-rata, dan curah hujan tahunan dari enam lokasi penelitian orangutan liar di Sumatera berkisar 0 - 2067 m, 18 - 31 oC, dan 1125 - 3967 mm. Tidak ada perbedaan yang signifikan pada anggaran kegiatan, pola makan, wilayah jelajah, jarak perjalanan harian dan komposisi kelompok orangutan di antara tipe hutan, dan tidak ada variabel geografis dan lingkungan yang berkorelasi dengan aspek perilaku dan sosial. Selain itu, tidak ada perbedaan yang signifikan antara aktivitas orangutan liar dan penangkaran, kecuali aktivitas makan. Selain sedikitnya lokasi penelitian, minimnya variasi aspek perilaku dan sosial menunjukkan sifat konservatif orangutan.
Keyword: activity budget, dietary, forage tree, nest

Judul: Variasi Geografis dan Lingkungan dalam Anggaran Kegiatan dan Pola Makan Lutung Jawa (Trachypithecus auratus)
Abstrak: Environmental and climatic conditions affect food abundance, affecting animals' dietary composition and diversity. Activity budgets are key information for evaluating the feeding strategy of primates. This study aims to analyze the effects of geographic and environmental factors on activity budget and dietary habits of Javan langurs (Trachypithecus auratus) across their geographical range or among forest types. This study’s data were gathered by conducting a web-based survey of the activity budget and dietary habits of the Javan langur. This study analyzed relationships between the geographical/environmental and activity, dietary composition, and social/behavioral aspects by the Spearman’s rank correlation tests and tested differences in the above variables among three forest types by the Kruskal-Wallis tests. The langurs’ diets were composed of foliage (49.0-75.7%), fruits (21.6-48.1%), and flowers (2.7-23.0%). The activities of the langurs were mainly composed of feeding (range: 20.2-44.2%), moving (9.8- 32.1%), resting (9.3-43.6%), and social behavior (2.5-28.9%). There were no significant differences between forest types and activity budget and dietary habits of the langurs and no significant correlations between geographic/environmental variations and their activity budget and dietary habits. The folivorous-based diets and their specialized digestive strategy would be the main reason for the lack of regional variation in activity and dietary habits.
Keyword: Colobines, conservation, feeding, folivorous, forest types

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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