In Malaysia, Alstonia spathulata Bl. is locally known as ‘Pulai Basong’ which distribute in peat forest. The separation of the chemical components from hexane and DCM crude extract of Alstonia spathulata was carried out using column chromatography (CC) and thin layer chromatography (TCL) techniques. A total of five known compound were isolated from the stem bark extracts and identified as: β-amyrin, β-amyrin acetate, lupeol acetate, stigmasterol and β-sitosterol. The elucidation structures of these compounds were established using 1D-NMR (1H, 13C and DEPT) and 2D-NMR (COSY, HSQC, HMBC) spectroscopic analysis, involving also comparison with data from the literature...

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In modeling growth of crustaceans, we normally encounter some difficulties such as the discrete growth fashion due to a process called moulting. All hard shells are shed periodically that hinder us from determining the age of an individual. To this end, we consider tag and recapture method to quantify growth parameters of wild crustaceans. For tag-recapture data, a sample of population is captured, tagged and released to its natural habitat. The growth estimation can be challenging, since the exact moulting time is normally unobserved. In this context, the intermoult period is not available for tag-recapture data. There are numerous statistical methodologies can be used for parameter estimations, for instance, the Generalized Linear Model (GLM) and the Generating Estimation Equation (GEE) method. Therefore, we are able to estimate individual growth without the age information. The conventional tagrecapture studies targeted for single recapture data that may mislead and cause biases whe.....

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Crustaceans exhibit discontinuous growth as they shed hard shells periodically. Fundamentally, the growth of crustaceans is typically assessed through two key components, length increase after molting (LI) and time intervals between consecutive molts (TI). In this article, we propose a unified likelihood approach that combines a generalized additive model and a Cox proportional hazard model to estimate the parameters of LI and TI separately in crustaceans. This approach captures the observed discontinuity in individuals, providing a comprehensive understanding of crustacean growth patterns. Our study focuses on 75 ornate rock lobsters (Panulirus ornatus) off the Torres Strait in northeastern Australia. Through a simulation study, we demonstrate the effectiveness of the proposed models in characterizing the discontinuity with a continuous growth curve at the population level. 2023 American Institute of Mathematical Sciences. All rights reserved...

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Many of courses under education system are not total designed according to students’ actual need and purpose of teaching and learning.This research attempts to investigate the relationship between students’ need and Arabic course for business purpose in Yin Chuan University, Ning Xia of china. A total of 60 final year students who are studying Arabic for business purpose courses were randomly selected from department of Arabic language of Yin Chuan University, self-reported instruments were distributed for data collection. The data analysis will depend on SPSS vision 2.0. Descriptive analysis was used to descript Category frequencies of the demographic variables, and Correlation method will apply to determine the relationship between two variables of students’ need and Arabic course for business purpose. It was found as a result of the analysis shows that there was significant relationship between students’ needs in teaching and learning Arabic for business purpose in Yinchuan .....

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