Judul: Keanekaragaman lumut hati dan lumut tanduk pasca erupsi di taman nasional gunung merapi, yogyakarta
Abstrak: Merapi is an active volcano, its latest eruption was occurred in October 2010. Merapi Mountain National Park Yogyakarta, characterized by tropical rain forest and located at the southern slopes of the vulcano. The eruption in October 2010 spreaded hot cloud and caused forest fires that damaged most of the vegetation where the bryophytes inhabit. This study aims to describe species diversity and construct identification key of the bryophytes, especially the liverworts and hornworts, of the national park post-eruption of Merapi. Sampling was conducted sixteen months after the latest eruption at three locations; Pronojiwo Hill, Kinahrejo, and Gandok. Purposive sampling method was applied to obtain samples of the bryophytes. A total of 20 bryophytes species representing fourteen genera and eight families, were found in the study. Those species consist of twelve leafy liverworts, five thalloid liverworts, and three hornworts. Arboreal bryophytes were only found in the Pronojiwo Hill, they were leafy liverworts. Terrestrial bryophytes occurred in all study areas. The liverworts and hornworts diversity in Pronojiwo Hill where trees still exist was higher than that in Kinahrejo and Gandok where the trees absence. Thalloid liverworts Marchantia treubii was common in the Merapi Mountain National Park.
Keyword: bryophyte, liverworts, hornworts, Merapi Mountain, posteruption.

Judul: Keanekaragaman Tumbuhan Bawah Pasca Erupsi Merapi di Taman Nasional Gunung Merapi, Yogyakarta
Abstrak: The eruption of Merapi Volcano in 2010 caused a great damage to the surrounding ecosystem. The recovery of surrounding ecosystem was done through succesional process. Organisms occur during early succesional stage are understory plants, thus they could be used as indicator of early stage succesion of damaged vegetation in Mount Merapi. The objective of this research was to describe and compare the diversity of understory plants after the eruption of Merapi Volcano in 2010 in Mount Merapi National Park, Sleman Region, Yogyakarta in two locations namely Gandok and Kaliurang Recreational Park. Gandok was categorized as high damaged location, while Kaliurang Recreational Park represented low damaged location. Vegetation was analyzed using quadratic method. Plants sample was identified in laboratory. Vegetation analysis generated the value of Significant Value Index (SVI), Diversity Index (H’), and Similarity Index (IS). Results showed that understory plant diversity of Gandok consist of 74 species and 63 genera, while Kaliurang Recreational Park consist of 49 species and 44 genera. The highest SVI was obtained by Digitaria nuda in Gandok and Brachiaria reptans in Kaliurang Recrational Park. Gandok and Kaliurang Recreational Park have a low similarity of understory community. Both location were categorized in medium diversity level.
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Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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