Judul: Pertumbuhan Semai Jabon (Anthocephalus cadamba) pada Media Bekas Tambang Pasir dengan Penambahan Sub Soil dan Arang Tempurung Kelapa
Abstrak: The effect of sand mining are environmental degredation and reduction of soil quality (physically, chemistry, or biological). The land of ex-sand mining could be marginal land and causes the revegetation barrier. Soil amendment is a necessary phase for this problem i.e. additional of sub soil and charchoal of coconut shell on the soil. The species selection also determine for revegetation result. Jabon (Anthocephalus cadamba) is an pioneer, adaptive and fast growing species. The aim of this reasearch are to analyze the effect of sub soil and charcoal of coconut shell increment to the growth of jabon seedling on ex-sand mining soil and to find out the optimum dose of sub soil and charcoal of coconut shell increment. The result of this research showed that sub soil and charcoal of coconut shell increment on ex-sand mining soil extend positive influence. The combination 500 g sub soil and 20 g charcoal of coconut shell gave the best growth for jabon seddling on ex-sand mining soil.
Keyword: sub soil, sand mining, coconut shell, charcoal, Anthocephalus cadamba

Judul: Pengaruh Pemberian Kompos dan Arang Kayu terhadap Pertumbuhan Semai Jabon (Anthocephalus cadamba Roxb. Miq.) pada Media Bekas Tambang Pasir
Abstrak: The sands mining can cause decreasing of sand number, make air pollution, damage the roads, and water quality degradation. The sands mining will produce waste in the form of ex sand mine. The characteristic of sands are low nutrients, less on water retention, and porous. This is an obstacle for revegetation in mining land that not suitable for plant growth. Revegetation activities conducted to know the plant growth in ex sand mine media. The selection of tree species is important to the success of revegetation in ex sand mine media. Jabon (A. cadamba) is fast growing species at a young age and grow in various soil. The method in this research is completely randomized design with two factorial. The first factor is compost and the second factor is wood charcoal. The parameters are height, diameter, and total dry weight. Statistical test showed that compost gave significant effect on jabon seedling height growth at 95% confidence interval. Interaction between compost and wood charcoal gave significant effect on jabon seedling height growth at the 95% confidence interval. Charcoal didn’t give significant effect on height, diameter, and total dry weight.
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Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology