Judul: Komposisi jenis dan struktur tegakan hutan di Cagar Alam Sibolangit, Sumatera Utara
Abstrak: Hutan merupakan suatu ekosistem yang merupakan hasil interaksi dari faktor-faktor biotik dan abiotik. Secara ekologis terbentuknya masyarakat suatu hutan adalah berangsur-angsur melalui pergantian vegetasi dan habitatnya. Masyarakat hutan adalah suatu sistem yang dinamik dan berubah hingga mencapai keadaan setabil. Tumbuhnya suatu jenis pohon di dalam suatu masyarakat hutan dipengaruhi oleh beberapa faktor, antara lain faktor klimatis, edafis, fisiologis dan faktor biotis. Terjadinya perubahan pada faktor-faktor tersebut diatas akan membawa pengaruh terhadap keadaan struktur maupun komposisi tumbuhan. Hutan dengan berbagai fungsi dan manfaatnya memberikan pengaruh yang sangat besar baik secara langsung maupun tidak langsung terhadap aspek ekologi, ekonomi, dan sosial. Pemanfaatan hutan dapat berjalan dengan lestari apabila informasi mengenai keadaan hutan diketahui dengan baik.
Keyword: 

Judul: Komposisi Jenis dan Struktur Tegakan Hutan di Cagar Alam Sibolangit, Sumatera Utara
Abstrak: Forest is an ecosystem that combines the interaction between biotic and abiotic factors. Ecologically, the formation of forest community formed gradually through the changing of the vegetation and habitat. Community of forest is a dynamic and always changing until it reaches a optimum stage. The growth of a tree species in a forest community is influenced by several factors, including climatic factors, edaphic, physiological and biotic factors. The changing in the factors mentioned previously will take effect on the vegetation structure and composition. Forest with a variety functions and benefits provide a tremendous influence both directly and indirectly to several aspects such as ecology, economic, and social. Utilization of forests can be well manage and reach the sustainably if the information about the forest condition are available. Sibolangit Nature Reserve which is located in Deli Serdang regency. The existence of the Sibolangit Nature Reserve with high biodiversity information still limited, therefore it is necessary needed to have a study of nature reserve in order to explore the benefits and potency of the nature reserve without disturbing the presence and preservation of the forest. Hence, we need a study to in the Nature Reserve Sibolangit of the forest, analyze species the composition, and structure. This research conducted from December 2008 until January 2009 using vegetation analysis techniques with the transeet methods. As preliminary, the transeet divided into plots of 20m x 20m to inventory the trees, 10m x 10m to analyze the pole, 5m x 5m to inventory the saplings, and the 2m x 2m to inventory the seedling. For the sampling unit it uses a sampling design in the form of systematic sampling with random start. Based on the results of observation, the seedlings and saplings dominated by Sono keling (Dalbergia latifolia). While for the poles and trees dominated by Angsana (Pterocarpus indicus). The diversity value in Sibolangit Nature Reserve classified as medium diversity. In Sibolangit Nature Reserve, the highest Similarity Index values was found in the north-south slope and the lowest one found in north-eastern slopes. Forest vegetation Sibolangit Nature Reserve in vertical point of view consists of three strata, namely the stratum A (tree height over 30 meters), stratum B (tree 20-30 meters high), and stratum C (tree height 4- 20 meters), where most of the tree population is distributed in the canopy stratum from 11 until 20 meters. All individuals in the forest show clustered distributed at both the tree and forest regeneration level.
Keyword: 

Judul: The Leukocyte Profile of Pregnant Friesian Holstein Cows vaccinated with Escherichia coli K99 polivalen vaccine.
Abstrak: The objective of this experiment was to study the leukocyte profile of pregnant cows vaccinated with E.coli K99 polivalen vaccine. Three pregnant Friesian Holsteins cows were used in this experiment. Before the administration of vaccine, the cows were given a series of immunomodulator injection for three days. The vaccinations were administered three times at 8, 6, and 4 weeks before calving. Blood were drawn through jugular vein, first before the administration of vaccines, then weekly until calving. Based on the observation, it can be concluded that the administration of E.coli K99 polivalen vaccine in pregnant cows not affected the leukocyte profile. Keywords : Escherichia coli vaccine, leukocyte profile, differential leukocyte
Keyword: