Judul: Conservation Genetics of Sumatran Orangutans (Pongo abelii)
Abstrak: Sumatran orangutan orangutans (Pongo abelii ) are one of the 25 critically endangered species in the world, endemic to Indonesia. As opposed to orangutanorangutans in Borneo, studies about population and conservation genetics of orangut an species in Sumatra are still rare, although this species need needs more urgent attention due to its small er population size and drastic habitat loss. This study was designdesigned to establish the Sumatran orangutan orangutans’ population genetics database database, using sample co llections from almost all currently existing ha bitats. The study also combine combines the genetic information with its demographic historyhistory, to acknowledge their unique population s, le leading to the species species’ taxonomic classification and conservation units. This st udy was dividedivided into three topics topics, using three genetic markers (autosomal loci, hypervariable region I mitochondrial DNA and Y Y-chromosomechromosome), with different sample size sizes and methods approach. The genetic samples were collected from nine sampling locations in Aceh and North Sumatra. In the first studystudy, a combined analysis of the autosomal loci, evolutionary paternal and maternal lineages with the genetic diversity pattern over populations is clarify ing the Sumatran orangutan population genetics, defining the f our present population habitathabitats in the wild. In the second study, private alleles of specific location habitathabitats were observe observed using 28 autosomal loci to look up the allelic variation within and between populations. In the last study, 52 diagnostic of singl single nucleotide polymorphisms (SNPs) were spe cified from 20 haplotypes using the evolutionary matrilineal genetic marker as Sumatran orangutan populations “DNA fingerprinting”fingerprinting”. In general, t his study aims to help establish ing the Sumatran orangutan conservat ion units. A new taxonomic classification is recommendedrecommended, splitting population s from the north and south of Lake Toba into two evolutionary significant units (ESUs) or two subspecies , as well as specify ing three distinct population segments (DPSs; one in t he south and two in the north area of Lake Toba , the northern area of Lake Toba is divided by the large Alas River riverine barrierbarrier). In addition, it is aiming to provide important information on specific population s, to identify the origin of their indivi duals and to simplify the decision making on the re re-introduction program s. It also addresses the requirements by the “Strategi dan Rencana Aksi Konservasi Orangutan Indonesia periode 2007 2007-2017” (Conservation Strategy and Action Plan of Indonesian Orangutan, period 2007 – 2017)
Keyword: Key words: Sumatran orangutan, population genetic, conservation unit, private alleles, diagnostic SNPs SNPs.

Judul: Habitat analysis and population estimation of sumatran orangutan (Pongo abeii Lesson 1827 at the Forest of Batang Toru, North Sumatra
Abstrak: The Batang TofU forest located in North, Center and South of Tapanuli, North Sumatra was recently found as one of Sumatran orangutan population habitat. A survey of trees species, nesting behavior and population of Sumatran orangutan was carried out during October 2007 up to January 2008 and aimed to analyze: (1) the forest structure, composition and trees distribution (including feeding and nesting trees); (2) estimated density and popUlation; and (3) the threat factors influenced the survival of Sumatran orangutan in Batang TofU forest. The results of the inventory of trees with diameter at breast height (DBH) 2: 10 cm in 3.84 ha areal sampling showed that 274 species in 56 families, represented by 1,896 individuals with total basal area of 148.9 m2lha and density of 498 treeslha. This forest was richer in tree species than other lowland forests in North Sumatra, Borneo and the Malay Peninsula and was dominated by Sapotaceae trees. The most prominent species were Tristania maingayi, Casuarina sumatrana, Quercus sumatrana and Ganua motleyana in every types of forest and differenced with Batang Gadis National Park which dominated by Dipterocarps. There were 96 feeding trees species in 25 families, represented by 536 individuals with total basal area of 46.7 m2lha. The prominent heights of feeding trees were below 30 m and distributed abundantly in the old moist secondary forests. The most important feeding trees for orangutans (Diospyros sp., Eugenia sp., Nephelium sp., Lithocarpus sp., Ficus sp., Artocarpus sp., Durio sp., and Garcinia sp.) were abundantly found in the old moist secondary forests, too. Orangutans commonly prefer to nest on the top of tree bar and the main branch of trees (DBH 20-30 cm; heights 15-20 m), especially in the middle canopy (20-30 m). Considering that there were enough feeding trees in this canopy. The most preferred nesting trees genus/species were Quercus sp., Syzygium sp., Shorea sp., Diospyros sp. and Lithocarpus sp. It was also invented 267 orangutan nests along 40.125 km cumulative lengths of line transects or equal with 0.54 percent of study area conducted at 11 sites. Densities were found higher in the old moist secondary forest while it was conversely lower density in the mixed forest. The distributions of nests were tended to clumped, related to the distribution of feeding trees. Orangutan population in 748.86 km2 ha potential habitat was approximately 337-421 individuals. Their distribution was limited by elevation and food availability. Human activities such as land conversion for agriculture purposes had become important factors affecting orangutan distribution. Field fact finding showed that many orangutan direct sightings and nests were located much closer to area human activities and logging concessions. This eventually has become real and concreted threat to their remaining population. It's needed to conduct further research in long-term monitoring and develop a strategic planning which promotes community involvement for the conservation of orangutan.
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Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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