Judul: Pendugaan biomassa jenis Rhizophora apiculata Bl. di hutan mangrove Batu Ampar kabupaten Kubu Raya, Kalimantan Barat
Abstrak: Kharakteristik khas mangrove memiliki keunikan yang berbeda dengan tipe hutan lainnya terutama pengaruh pasang surut air laut sehingga berpenganh pada jenis vegetasi yang tumbuh pada kawasan ini. Fungsi ekologis hutan mangrove salah satunya sebagai rosot karbon menjadi pertimbangan penting bagi upaya konservasi suatu kawasan. Permasalahan lingkungan menjadi semakin kompleks karena kerusakan hutan di negara ini akibat deforestrasi, tidak terkecuali untuk kawasan mangrove. Diperkirakan antara tahun 1982 dan 1992 luas hutan mangrove telah berkurang 30% (Soemanvoto 2001). Dalam upaya untuk mengkaji kandungan karbon yang mampu diserap maupun emisi karbon yang dikeluarkan akibat deforestrasi, dilakukan penelitian pendugaan biomassa untuk memperkirakan kandungan karbon di hutan mangrove yang berada di Indonesia salah satunya pada jenis yang mendominasi kawasan mangrove Batu Ampar, Kalimantan Barat yaitu jenis Rhizophorn apiculata.
Keyword: 

Judul: Pendugaan biomassa beberapa kelas umur tanaman Rhizophora apiculata pada areal PT. Bina Ovivipari Semesta, Kabupaten Kubu Raya, Kalimantan Barat
Abstrak: Mangrove forests develop along coastlines that are always or regularly inundated by sea water and affected by tides but not affected by the climate. Ecological function of mangrove as carbon sink becomes important thing since climate change tends to more interesting issue. Trees absorb CO2 through photosynthesis and convert it into organic carbon and store it in biomass of the tree body. PT. Bina Ovivipari Semesta is a private company has permission IUPHHK-HA on the area of mangrove forest. This company replant the logged over area. The plants on the logged area will have different content of biomass keep pace with the growth of these plants per year. The purpose of this research is to develop allometric equation model to estimate biomass of Rhizophora apiculata on several age classes. The study was conducted at mangrove forest of PT. Bina Ovivipari Semesta, Kubu Raya District, West Kalimantan Province. It was conducted during July-August 2010. Data that were collected consisted of trees’ dimension: wet weight of each segment, sample wet weight of test sample per segment, and dry weight of test sample per segment. Data that were collected with destructive methods. The data was analyzed using Minitab software release 14 with statistic values test and validation test. The ratio values of water content and wood specific weight have inverse relation. The value of trees’ water content tends to decline with increasing trees’ age, while the value of wood density tends to increase with increasing trees’ age. Younger trees have larger cell cavities so the water can fill in the cavities easily. The smaller the cell cavities in mature trees are caused by wood contents. Biomass of tree on age of three, six, and nine years were 0,96 kg/ind; 5,38 kg/ind; and 39,11 kg/ind respectively. It shows that biomass value of trees’ parts tend to increase together to the age of the trees. Allometric equation of Rhizophora apiculata on three to nine years of age gives total biomass in kg, respectively: leave (B = 0,0204174 D1,95), twig (B = 0,0074131 D2, 23), branch (B = 0,0213796 D2,1), bar (B = 0,0027542 D4,01), areal root (B = 0,0079433 D3,25) and total biomass (B = 0,027542 D3,22).
Keyword: 

Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
Keyword: