Vol. 50 No. 3 (2018)

In this paper, a numerical procedure called multistage optimal homotopy asymptotic method (MOHAM) is introduced to solve multi-pantograph equations with time delay. It was shown that the MOHAM algorithm rapidly provides accurate convergent approximate solutions of the exact solution using only one term. A comparative study between the proposed method, the homotopy perturbation method (HPM) and the Taylor matrix method are presented. The obtained results revealed that the method is of higher accuracy, effective and easy to use.

A two-compartment mathematical model is proposed for the study of individual plant growth dynamics with time lag due to the presence of toxic metals in the soil. It is assumed in the model that nutrient uptake by the roots is hindered by the presence of the toxic metals. It is further assumed that there is less transfer of nutrients from the root compartment to the shoot compartment due to the toxic metals. However, the nutrient concentration decreases in the root compartment as well as in the shoot compartment, resulting in a decrease of the structural dry weight of the roots and shoots…

The respective influences of the Indian Ocean Dipole (IOD) and El Niño-Southern Oscillation (ENSO) on Indonesian precipitation were evaluated using monthly precipitation data from the Global Precipitation Climatology Centre (GPCC) for January 1948 to December 2013. Simultaneous correlation between seasonal precipitation anomalies and climate indices for these two types of climate modes revealed that IOD events have a significant correlation with the precipitation over southern Sumatra, Java, southern Kalimantan, the Nusa Tenggara Islands, some parts of Sulawesi and eastern Papua. Meanwhile,…

In this work, the dynamics of one particular fibril were investigated through high-resolution multi-wavelength images with high cadence obtained from the Dutch Open Telescope. Based on exceptional observation data of Active Region 10789, 13th July 2005, we investigated the alternating fibril pattern using tomography of the multi-wavelength band, consisting of the hydrogen alpha line center and also the blue wing, the calcium II H line, and the G-band. Phase difference and coherence analyses were conducted for several points along the fibril and (k, ω) analysis was conducted to understand the…

Lithium titanate, LTO, was synthesized by solid state reaction with Li2CO3 and TiO2 powder as precursors. The result was characterized to investigate its crystal structure, phase content, cell parameters, surface morphology, electrical conductivity and its performance as electrode in a lithium ion battery. XRD analysis with Le Bail refinement showed that the prepared materials consisted of 4 phases of Li4Ti5O12, Li2TiO3, anatase TiO2 and rutile TiO2. The surface morphology was still not homogeneous, with an average grain size of 0.533 ± 0.157 µm. When 1% LTO was mixed with graphite and used…

Heat shock protein 90 (Hsp90) is responsible for the correct folding of many cellular proteins. Several Hsp90 inhibitors have been developed for cancer treatment. The present in silico study aimed to evaluate the potential of several porphyrin derivatives conjugated with anthraquinone groups as Hsp90 inhibitors by using simulation of molecular docking and molecular dynamics. The binding mode of porphyrin hybrids to Hsp90, which was examined by using AutoDock 4.2, showed that all six porphyrin compounds fit well in the binding pocket of Hsp90. The pi-cationic interactions with Lys58 were…

Information on tree community structure and composition is needed in forest management and restoration. These data can be obtained using a permanent plot for studying forest dynamics, including species-specific characteristics. These characteristics are useful in the identification of native species for commercial and restoration purposes. This study aimed to describe the tree community structure and composition of a one-hectare permanent plot in the montane zone of Mount Kerinci. Data collection was conducted from July to August 2016 on Mount Kerinci, Jambi. A plot was established at…