Judul: Efektivitas Pupuk Organik terhadap Pertumbuhan, Produksi, dan Kadar Hara NPK Daun Jagung Manis di Latosol Darmaga
Abstrak: Sweet corn is seed plant which is commonly planted in Indonesia because of it's sweet taste and contain high carbohydrate. One of the problems in cultivation of sweet corn is low soil fertility, due to the lack of soil nutrient availability and organic matter. To solve that problem can be done by applying organic and anorganic fertilizers. Organic fertilizer is able to increase chemical fertilizer efficiency through improving of physical, chemical and biological of soil. So it is expected to increase the production of plant significantly. The objective of this research is to study the effectiveness of organic fertilizers that was combined with inorganic fertilizer on the growth, production, and N, P, K content of sweet corn leaf in Latosol Darmaga. The field experiment was conducted at the University Farm IPB and plant analisis in the laboratory of soil chemistry and fertility, Department of soil science and Land Resources Faculty of Agriculture IPB. The materials used were organic fertilizers, inorganic fertilizers, seeds of sweet corn (Seleksi Darmaga III), furadan, and agricultural lime. The design of the experiment was a randomized complete block design (RCBD) with a single treatment consisted of 7 treatments which was repeated 3 times each, so there were 21 experimental units. Those seven treatments were: (1) control, (2) Standard (S), (3) 0.5 S + 1.5 PO, (4) 0.5 S + 1 PO, (5) 0.75 S + 1 PO, (6) 1 S + 1 PO and (7) 0.75 S + 1.5 PO. The parameters measured were plant height, production (corn cobs weight including the cornhusk and stover weight), and N-, P-, K-content of corn leaf. The results of this research showed that additional of organic fertilizer with inorganic fertilizer was effective in improving the growth, production, and N, P, K content of sweet corn leaf. The production for treatment 1 S + 1 PO was 14.31 t/ha greater (2.37 t/ha) than standard treatment, and 11.81 t/ha greater than control treatment (no fertilizer application).
Keyword: 

Judul: Efektivitas Pupuk Organik Granul terhadap Pertumbuhan, Produksi dan Kadar Hara NPK Daun Jagung Manis pada Latosol Dramaga
Abstrak: Latosol fertility is generally low due to low nutrient availability and organic matter content, so addition of anorganic fertilizer only will not provide optimal production of plants. Therefore, additional of organic fertilizer must be done. The objective of this research is to study the effectiveness of granulated organic fertilizer which was combined with standard fertilizer on the growth, production, and NPK contents of sweat corn leaves in Latosol Dramaga. The field experiment was conducted in the University Farm IPB, from Februari to August 2012. The nutrient content was analyzed in the Laboratory of Soil chemistry and Fertility, Faculty of Agriculture, IPB. The design of research was completely randomized block design with single factor, that was combination of anorganic fertilizer (standard) with organic fertilizer, which consisted of 7 treatments: control, standard, 50% standard + 100% organic (0,5S+1PO), 50% standard + 150% organic (0,5S+1,5PO), 75% standard + 100% organic (0,75S+1PO), 75% standard + 150% organic (0,75S+1,5PO), and 100% standard + 100% organic (1S+1PO). The result of the research showed that the granulated organic fertilizer increased of growth, production of corn, and nutrient content of corn leaves effectively. The two treatment combinations (1S+1PO) and (0,75S+1PO) showed the best performance, which was indicated by the weight of corn with huskcover and value of RAE i.e. 15,58 t/ha and 162,07% (1S+1PO), and 13,97 t/ha and 128% (0,75S+1PO), respectively. The effect of both treatment combinations above were higher than standard treatment (12,58 t/ha and 100%).
Keyword: 

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model