An E-Learning Investigation into Learning Style Adaptivity

Abstrac

Hybrid Profiling in Information Retrieval

Abstract-One of the main challenges in search engine quality of service is how to satisfy the needs and the interests of individual users. This raises the fundamental issue of how to identify and select the information that is relevant to a specific user. This concern over generic provision and the lack of search precision have provided the impetus for the research into Web Search personalisation. In this paper a hybrid user profiling system is proposed -a combination of explicit and implicit user profiles for improving the web search effectiveness in terms of precision and recall. The proposed system is content-based and implements the Vector Space Model. Experimental results, supported by significance tests, indicate that the system offers better precision and recall in comparison to traditional search engines

Green Synthesis of Spiro Compounds and the Phytochemical Investigation of Diethyl Ether Fraction of Camu-Camu (\u3ci\u3eMyrciaria dubia\u3c/i\u3e) Leaves

There are a lot of lucrative plant species found in the Amazon and camu-camu (Myrciaria dubia (H.B.K.) Mc Vaugh) is distinct among them. This is due to its exceptional Vitamin C content which varies from 1600 to 6112 mg/100g of pulp. Besides the fruits which is popularly used, different parts of camu-camu plants including the stems, leaves, seeds, barks, and roots are also traditionally used in folklore practices for treating various ailments and diseases and research has showed the presence of antioxidant, antimicrobial, anticancer, anti-inflammatory agents present in these parts. In this study, the characterization of a bioactive compound, isolated from the diethyl ether extract of camu-camu (Myrciaria dubia) leaves was conducted using Fourier Transform Infrared spectroscopy (FT-IR), mass spectroscopy (MS), and nuclear magnetic resonance spectroscopy (NMR). A more environmentally benign green synthetic method was used to synthesize spiro compounds and their derivatives in a five-component reaction involving 1,3-diketo, hydroxyl amine, activated methylene, isatin, ammonium acetate, sulfamerazine, and sulfathiazole. Microwave irradiation was used in a short time range (5 – 30 min) and moderate temperature (80°C), with water as a solvent, and N, N-Diisopropylethylamine (DIPEA) as a catalyst to give high yield of products. This presents a sustainable and faster alternative to the classical synthesis approach