Judul: The influence of some nutritional conditions on nodulation of and nitrogen fixation by peanut plants
Abstrak: The objective of this work was to investigate the effects of nitrogen, phosphorus, calcium and magnesium on the growth and nitrogen fixation process in peanut plants under greenhouse conditions. The results of a series of preliminary experiments conducted to determine satisfactory growing conditions in terms of rooting medium and nutrient solution are reported. Efforts were made to determine a satisfactory ratio between quartz gravel and oyster shells for the rooting medium. Studies were also conducted to determine the stage of growth required for the development of adequate nodules. The effects of the addition of phosphorus and different forms of calcium along with the influence of magnesium on peanut growth and nodulation were studied. The effect of time of application of nitrogen on growth and nodulation also was studied as well as the influence of pH. It was found that the plants could probably be harvested between six and ten weeks of age. The best pH seemed to be about 5.8. Satisfactory levels of phosphorus, calcium and magnesium were determined. Oyster shells worked well as part of the substrate. It might have been better to have supplied the calcium in a form other than oyster shells because of the nutrients other than calcium found in the shells. An experiment was conducted using N isotopic nitrogen as a tracer to determine the effect of nitrogen on total growth, nodulation and nitrogen fixation by peanut plants. Low levels of nitrogen aided nodulation. not inhibit nodulation completely. Very high levels did Results of this experiment indicate that the addition of some nitrogen to some field grown peanut plants may be beneficial and profitable.
Keyword: Nitrogen, Phosphorus, Grown peanut plants

Judul: The Growth Response of Green Beans (Phaseolus  vulgaris L.) on Various Growing Media and Dose of NPK Fertilizer
Abstrak: Various plant growing media (PGM) were developed as an alternative to the issues of limited crop land available to support plant growth well enough so that it can produce the expected production. Proper PGM should be able to maintain the availability of water, oxygen and essential nutrients for plants. Fertilization to supply plant nutrients are often followed by increases the value of electrical conductivity (EC). Zeoponic that made up of zeolites, cocopeats, and compost had high cation exchange capacity (CEC) and good buffer capability against the increasing of EC due to the fertilization. This study was aimed to determine the effect of PGM and dose of fertilizer application on the chemical properties of PGM, growth and production of green beans (Phaseolus vulgaris L). The NPK fertilizer experiments on green beans were in two different types of media with factorial completely randomized design (CRD) which were zeoponics and nonzeoponics, as well as four levels fertilization doses (0, 1, 2, and 3 g kg-1 ). Plants respond to the treatments variously. The usage of both PGM took a significant effect in pH, EC, nitrogen (available-N), phosphorus (available-P and total-P), CEC, cation bases (Ca, Mg, K, Na), base saturation, organic-C, micro nutrients (Fe, Cu, Zn, Mn) in media, plant height, and the number of plant leaves. The treatment of fertilizer doses significantly effected organic-C, available-N, height of plant, the number of plant leaves, the weight of bean, the wet and dry weight of plant. Generally, growth and production of green beans in zeoponic media were faster than in nonzeoponics. The best results were in the treatment of Z2 (zeoponic + NPK fertilizer 2 g kg-1 ) with the weight of green beans (120,47 g), the dry weight of plant (14,48 g), the height (76,02 cm) and number of plant leaves (29 leaves).
Keyword: fertilization, horticulture, zeolite, zeoponik

Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular