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: Pengaruh Pengendalian Langkap (Arenga obtusifolia) Terhadap Komposisi Tumbuhan Pakan Badak Jawa (Rhinoceros sondaicus
Abstrak: Langkap is a plant that invades on javan rhino habitat. Thus, a proper control management of langkap needs to be carried out by using logging method. Research study in the effect of langkap control management of the plant composition is done to determine effectiveness of logging methods. Research had been conducted during in June 2013 at Kalejetan Resort, Selokan Bayun- Seuseupan Block, Ujung Kulon National Park. Data were collected using vegetation analysis in eight plots of control management to monitor the diversity of plants, and also to monitor 53 control plots to find out the correlation between javan rhino visitations and langkap control management. Based on the result of the research, cut-leave logging method is the best method to conduct. Furthermore, by eliminating seedling and sapling of langkap will also increase the diversity number of javan rhino food plants. Increasing numbers of javan rhino visitation on the sites known related to the growing levels of javan rhino food plants.
Keyword: Ujung Kulon National Park., langkap, javan rhino, control management

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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