Judul: paleorekonstruksi vegetasi dan lingkungan menggunakan fosil polen dan spora pada formasi Tapak Cekungan Banyumas kala plio-plistosen
Abstrak: Pollen and spores fossils have important information about the flora, vegetation, climate, and environment associated with processes and conditions during sedimentation process in the past.The main objective of this study was to disclose information, especially the ecology of palaeoflora, vegetation, and environmental deposition based on pollen and spores fossils, which were found in sedimentary rocks of the Banyumas Basin Tapak Formation.Totals of 166 sediment samples were prepared using modified palynology standard methods. Palynological analysis were carried out based on the habitus, habitat, total palynomorph and diagnostic pollen and spores fossils.This research found 72408 palynomorph fossils that consisted of 48570 pollen and spores fossils and 23838 marine fossils consisted of dynoflagellate cysts and foraminifera test lining (FTL). Pollen and spores fossils consisted of 76 types that were categorized into: 20 types categorized into species, 41 genus and 15 familia level. Based on habitus, 76 types of pollen and spores fossils were grouped into: 41 taxa (53.95%) of arboreal plants (AP),15 taxa (19.74%) of non arboreal plants (NAP), and 20 taxa (26.32%) of Pterydophytes.The presence of AP taxa were more dominant than the NAP taxa.This suggested that arboreal palaeoflora and vegetation were more developed in Banyumas Basin Tapak Formation. Pollen and spores fossils evidence indicated that the environment in the Banyumas Basin Tapak Formation was surrounded by mountainous morphology and the water flow system as pollen and spores media transport from mountainous to the transitional area through lowlands, freshwater, and mangrove swamps. The overall climate of Tapak Formation showed there was no clear differences between hot-wet and cold-dry climates.The presence of paleoflora taxa in Tapak Formation were relatively stable.The mean of similarity index ranged from 53.3 to 59.64%, which was categorized as high similarity criteria among sediment samples from each location, although the diversity was categorized from low to moderate. Generally, environmental deposition on Tapak Formation was a transitional area that was influenced by dynamic marine environment intensity.
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Judul: The Biodiversity of Hornwort (Anthocerotophyta) in Mount Slamet
Abstrak: Hornworts (Anthocerotophyta) are one of the three divisions of nonvascular plants. Hornworts are easily recognized based on the structure of thalloid gametophyte so that it is similar to the thalloid liverworts, but hornworts generally have cells with 1-8 chloroplasts per cell, and a long cylindrical sporophyte structure similar to horns. Hornworts are generallly found in open and humid habitats such as along the edges of hiking trails in mountain forests. The hornworts in Java to date are reported to number 28 species, however only one species has been reported occurs in the area of Mount Slamet, Central Java. This research was conducted to inventory diversity, providing the key identification and description of the hornworts species of Mount Slamet. Specimens of hornworts were collected along the hiking trail of Mount Slamet in three locations, namely Baturraden (Banyumas Regency), Gunung Malang (Purbalingga Regency), and Guci (Tegal Regency). Morphological and anatomical observations of tha specimens are carried out for the purposes of species identification. Characters in the gametophyes and sporophytes are used to develop keys and descriptions of species found in the area of Mount Slamet. The observed specimens are deposited at the Herbarium Bogoriense (BO). The gametophyte of hornworts species found in this study have thallus varied from small to large, either rosette or strap-shaped, light green to dark green. The transverse section of talus has parenchyma tissue with mucilage cavities or solid (without mucilage cavities). The cells of the talus have 1-8 chloroplasts per cell with or without pyrenoids. The sporophytes have a short to long involucrum with a smooth to rough surface, the capsule when ripe is black or yellow to orange red, the stomata on the epidermis of the capsule wall are present or absent. Spores are either unicellular or multicellular; grey to black, yellow in color or hyaline; with or without chloroplasts. The distal and proximal surface of spores have various ornamentation. Triradiate markings on the proximal surface of spores are prominent or obscure. Pseudoelaters are linear, either unbranched or branched, or in the form of spiral bands, consisting of 1-5 short or long cells, and either hyaline to brown in color. The identification of 120 hornwort specimens from Mount Slamet yield six species. One of them, Dendroceros difficilis, has previously been reported found in Baturraden Mount Slamet and was rediscovered in this study. Accordingly, the other five species, namely Anthoceros punctatus, Folioceros fuciformis, Phaeoceros carolinianus, Phaeoceros exiguus, Dendroceros difficilis, Megaceros flagellaris are new records for Mount Slamet. In fact, one of them, Phaeoceros exiguus, is a new record for Malesia. All of the hornworts species of Mount Slamet, except the epiphytic Dendroceros difficilis that found on tree bark or braches, are found on various terrestrial substrates such as soil, rocks, roots and trunks of dead trees in various moish habitats which has slightly closed canophy such as in mountain forests, or in the open vegetation such as around the waterfalls, along the banks of streams, and agricultural land., Lumut tanduk (Anthocerotophyta) merupakan satu dari tiga divisi tumbuhan tidak berpembuluh. Lumut tanduk mudah dikenali berdasarkan struktur gametofit bertalus sehingga mirip
Keyword: bryophyte flora of Java, bryophytes flora of Malesia, new records, Phaeoceros exiguus

Judul: Invers dari Matriks Tridiagonal Jacobi
Abstrak: Suatu matriks berukuran n×n dinamakan matriks tridiagonal jika untuk . Karya ilmiah ini memberikan algoritma yang mudah untuk menemukan invers ( dari matriks tridiagonal Jacobi yang simetrik dan nonsimetrik. Setiap elemen pada matriks tridiagonal ini adalah bilangan real. Terdapat 3 lema dan 2 teorema untuk menentukan . Lema pertama menunjukkan persamaan utama dalam membuktikan lema-lema dan teorema-teorema selanjutnya. Invers dari matriks yang simetrik dibuktikan oleh lema kedua yang menunjukkan elemen-elemen baris ke- dari . Selanjutnya, lema kedua dilengkapi dengan teorema pertama yang menunjukkan elemen-elemen dengan . Invers dari matriks yang nonsimetrik dibuktikan oleh lema ketiga yang menunjukkan elemen-elemen dengan dan elemen-elemen dengan dibuktikankan oleh teorema kedua.
Keyword: symmetric, nonsymmetric, matrix