Judul: Autekologi dan Kesesuaian Habitat Langkap (Arenga obtusifolia Mart.) di Cagar Alam Leuweung Sancang, Jawa Barat
Abstrak: Langkap (Arenga obtusifolia) is one species of the Arecaceae. Its utilization limited, compared with their fast growth and regeneration in their natural habitat and this species tend to be invasive. Autecology and habitat suitability research is needed for domestication and control of langkap in the Leuweung Sancang Nature Reserve. The aim this study was to analyze the abundance and population structure, distribution pattern, the associations of langkap with other species, the characteristics of the habitat components and their effects on it populations and build spatial models of habitat suitability in the Leuweung Sancang Nature Reserve. Data collected was performed by using strip transect method with systematic sampling. Langkap has become the dominant species in Leuweung Sancang Nature Reserve on saplings and pole level. Langkap population structure shows normal structure population and expected to maintain their population in Leuweung Sancang Nature Reserve. The distribution pattern of langkap in all level of growth followed clumped pattern. Langkap has low association level with 13 other plant species. The vegetation factors (saplings density, pole density, tree density, basal area of poles, basal area of trees and shade), topography factors (distance from the river), micro-climate factors (temperature, humidity, and radiation intensity), human disturbance factors (distance from the road and the distance from the garden) and edaphic factors (clay content, sand content, C organic, C/N ratio, and calcium) were found to be affecting the abundance of langkap. Analysis of spatial modeling habitat suitability of langkap through binary logistic regression with independent variables in the form of the Forest Canopy Density (FCD), slope, distance from the river and Normalized Difference Moisture Index (NDMI) have been able to predict habitat suitability of langkap in Leuweung Sancang Nature Reserve.
Keyword: autecology, habitat suitability, langkap, Arenga obtusifolia, spatial modeling, Leuweung Sancang Nature Reserve

Judul: Studi mekanisme pertahanan langkap (Arenga obtusifolia Blumme ex Mart.) terhadap herbivory di Taman Nasional Ujung Kulon Jawa Barat
Abstrak: Taman Nasional Ujung Kulon merupakan habitat terakhir badak Jawa (Rhinoceros sondaicus Desmarest 1822) dengan populasi yang relatif kecil (± 47: 27-56 ekor, MacGriffiths, 1993). Dinamika ekologis (ekosistem) di kawasan yang menjadi habitat badak Jawa akan mempengaruhi perkembangan populasinya. Salah satu aspek penting tekanan biologis yang terjadi terhadap habitat badak Jawa adalah suksesi vegetasi khususnya adanya kecenderungan invasi langkap. (Arenga obtusifolia) dan kaitannya dengan penyediaan tumbuhan pakan badak (Muntasib, et al., 1992). Berdasarkan kondisi tersebut, sangat penting dilakukan penelitian yang bertujuan untuk mengidentifikasi karakteristik ekologi langkap, khususnya yang berhubungan dengan kapabilitas invasi dan pengaruhnya terhadap dinamika habitat badak Jawa (Haryanto, 1992). Tujuan penelitian ini adalah mengidentifikasi mekanisme perta- hanan buah langkap terhadap herbivory, yang terdiri atas identifikasi jenis satwa liar pelaku herbivory; identifikasi kelas umur buah yang dikonsumsi dan identifikasi mekanisme interaksi, serta menganalisis kandungan natrium oksalat dalam pendugaan mekanisme pertahanan lang- kap terhadap herbivory; menganalisis golongan senyawa metabolit se- kunder dan analisis proksimat. Pengamatan lapangan dilakukan di Resort Cibunar pada bulan Januari 1995 yaitu dengan pengamatan langsung dan pengamatan tak langsung. Analisis kandungan senyawaan kimia dilakukan pada bulan Juli 1995 meliputi analisis kandungan natrium oksalat dengan metode titrasi oksidi-reduktometri dan uji umum golongan senyawaan metabolit sekunder (alkaloid, flavonoid dan terpenoid) dilakukan di Lab Kimia Analitik Jurusan Kimia P-MIPA IPB; sedangkan analisis proksimat dilakukan di Lab Biokimia dan Lab Kimia Analisis Terpadu IPB. ...
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Judul: Photosensor producing based on ferroelectric material of Ba0,5Sr0,5TiO3 doped by Ferrium Oxide (Fe2O3) on a P-Type Silicon Substate Si (100) applied as a digital camera with a single pixel image sensor
Abstrak: Thin film Ba0,5Sr0,5TiO3 (BST) doped with Fe2O3 was grown on p-type silicon substrate (100) using chemical solution deposition (CSD). It used the solvent 2-methoxyethanol with annealing temperature of 850°C and the doping treatment Fe2O3 of 2.5, 5, 7.5, 10 % of the mass formed BST. Pure BST had the highest absorption of 600 nm of light wavelength. Additions Fe2O3 moves highest absorption in the range of 560 nm. Fe2O3 addition was strengthening thin film sensitivity to the effects of light. In general, doping Fe2O3 10% was result the best absorbance and current-voltage of BST thin film. Electrical properties of thin films BST include dielectric, photoconductivity, and dissipation energy. Based on the current-voltage (I-V) analysis, pure BST and doped BST showed photodiode properties. Dielectric values obtained in the range from 23.32 to 243. Based on electrical conductivity data and energy dissipation, BST thin films have shown photodiode characteristics and are therefore suitable as light sensors. The image sensor in a digital camera is also a light sensor. This BST thin film has been scientifically proven to be a light sensor and also it can be applied as an image sensor. This is a novelty image sensor based on thin film Ba0.5Sr0.5TiO3.
Keyword: barium strontium titanate, thin film, photodiode, image sensor, digital camera