Judul: Cytotaxonomy Pteris ensiformis Burm.f.
Abstrak: The cytotaxonomy of Pteris ensiformis Burm.f. from several places in Indonesia have been studied. The information about infraspesific variation of P. ensiformis and the relationships within P. ensiformis can be used to clarify the intraspecies delimitation of P. ensiformis. The objectives of this study were to examine morphological, cytological and mode reproduction of P. ensiformis and to clarified the correlation between mode of reproduction, ploidy level and morphological variation in P. ensiformis. Therefore, the aim of this study was to examined the intraspesific variation of P. ensiformis in Indonesia. This study was conducted from September 2012 to June 2013. The morphological character was examined from 60 collections of living plants originated from Gorontalo, Lombok and various places in Java, added the specimen from Herbarium Bogoriense (BO). Cytological observations were conducted by observing somatic chromosome of root tips using squash methods. Modes of reproduction were determined by counting the number of spores of each sporangium. New cytological record of P. ensiformis var. victoriae have been found from Indonesia i.e 2n=58 (diploid sexual) from Gorontalo, Celebes and 2n=87 (triploid) from Lombok Island and Bogor West Java. The diploid sexual of var. victoriae has smaller in habitus than that of the triploid races. Cytotype tetraploid sexual (2n=116) of var. ensiformis, collected from various places in Java is an important information of cyto-reproduction data of var. ensiformis in Indonesia. Based on morphological data, P. ensiformis consistenly can be classified into two varieties namely P. ensiformis var. ensiformis and P. ensiformis var. victoriae. However, futher study to clarify their relationship among varieties is strongly recommended.
Keyword: chromosome numbers, cytotypes, Pteris ensiformis Burm.f.

Judul: Sitologi dan Tipe Reproduksi Pteris multifida Poir. (Pteridaceae)
Abstrak: Cytological observations have been carried out by several researchers in South Chine, Japan, Ceylon, Hongkong, Himalaya, and Java. The results from various regions showed that P. multifida had a fairly high genetic variation, namely diploid, triploid, and tetraploid types. Therefore cytological and reproductive study on P. multifida from its geographical distribution areas need to be done. The objectives of this research were observe the somatic chromosome number and reproductive type of P. multifida, and to recognize the relationship between morphological variation and its ploidy level as well as stomatal index. Plants were collected from several localities in Bogor. Ploidy level was determined by observing somatic chromosome number by using squash methods. Reproductive type was determined by counting spore number in each sporangium. Morphological characters examined were the stipe, lamina, pinnae, veins, and indusium. Observations of stomata and epidermis of leaves were done by making an incision paradermal leaf. Pteris multifida has two ploidy level and reproduction type, namely apogamous triploid (2n = 87) and sexual tetraploid (2n = 116). The two ploidy level could not be distinguished based on morphological characteristics, but they can be differentiated by their epidermal cells number. Apogamous triploid has fewer number of epidermal cells, the sexual tetraploid has a greater number of epidermis.
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Judul: Rancang Bangun Alat Pengukur Percepatan Gravitasi pada Bidang Miring Berbasis Microcontroller Arduino Uno
Abstrak: Pada penelitian ini telah dilakukan pembuatan alat pengukur percepatan gravitasi pada bidang miring yang terbuat dari acrylic. Pengukuran waktu dilakukan menggunakan RTC DS1307 sebagai pengganti stopwatch. Photodioda dan LED Infra Red diletakkan di posisi awal dan akhir dari bidang miring. Sensor ultrasonik digunakan untuk mengukur ketinggian bidang miring serta sudut elevasinya. Proses pengambilan data dilakukan untuk 5 kali variasi ketinggian, masing-masing dengan 30 kali pengulangan. Hasil pengukuran menunjukkan semakin besar sudut elevasi, semakin singkat waktu yang dibutuhkan benda, sehingga percepatan semakin besar. Percepatan gravitasi rata-rata dihasilkan adalah 9.86 m/s2 dan ralat relatif percepatan gravitasi sebesar 0.5%.
Keyword: Led Infra Red, photodiode, ultrasonik