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Clustering the learning patterns of adults with low literacy skills interacting with an intelligent tutoring system
No full textA common goal of Intelligent Tutoring Systems (ITS) is to provide learning environments that adapt to the varying abilities and characteristics of users. To do this, researchers must identify the learning patterns exhibited by those interacting with the system. In the present work, we use clustering analysis to capture learning patterns in over 250 adults who used the ITS, CSAL (Center for the Study of Adult Literacy) AutoTutor, to gain reading comprehension skills. AutoTutor has conversational agentsth at teach literacy adults with low literacy skills comprehension strategies in 35 lessons. These comprehension strategies align with one or more of the following levels specified in the Graesser-McNamara theoretical framework of comprehension: word, textbase, situation model and rhetorical structure. We used the adult learners’ average response times per question and performance across lessons to cluster the students’ learning behavior. Performance was measured as the proportion of 3-alternative-response questions answered correctly. Lessons were coded on one of the four theoretical levels of comprehension. Results of the cluster analyses converged on four types of learners: proficient readers, struggling readers, conscientious readers and disengaged readers. Proficient readers were fast and accurate; struggling readers worked slowly but were not accurate; conscientious readers worked slowly and performed comparatively well; disengaged readers were fast but did not perform well. Interestingly, the behaviors of learners in different clusters varied across the four theoretical levels. Identifying types of readers can enhance the adaptivity of AutoTutor by allowing for more personalized feedback and interventions designed for particular learning behaviors
FriPEL: Friendship privacy educational labware
No full textAs social media grows increasingly in popularity, so do people\u27s concerns about their privacy disclosure. Considering the large amount of time the younger generations spend on online social networks, educational activities are needed to promote privacy protection. This paper presents an initial effort on exploring a hands-on learning approach to educate students on social media privacy. Specifically, a labware was developed to educate students that their query behaviors in online social networks may disclose the private relationships of other users on the site. The labware aims at making students aware of the privacy issues on social media, understanding the costs of privacy protection, stimulating their interests, and improving students self-efficacy. This paper discusses the design and implementation of the labware, which was evaluated among a group of student volunteers through the lecture and hands-on activities. Student feedback was very positive and encouraging
Interaction energy of a pair of identical coplanar uniformly charged nanodisks
No full textWe consider a nanosystem consisting of two coplanar uniformly charged nanodisks that are coupled via Coulomb forces. Such a model represents a typical situation encountered in two-dimensional semiconductor quantum dot systems of electrons. We provide an exact integral expression for the interaction energy between the two coplanar nanodisks as a function of their separation distance. It is found that the difference between a standard Coulomb potential and the current one has features reminiscent of a Lennard-Jones interaction potential. The results derived can be useful to understand formation of clusters and/or aggregates in systems of coplanar charged nanodisks that contain electrons
Growing Ideas Impacting Lives College Of Agriculture And Human Sciences
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An Aminoimidazole Radical Intermediate in the Anaerobic Biosynthesis of the 5,6-Dimethylbenzimidazole Ligand to Vitamin B12
No full textOrganisms that perform the de novo biosynthesis of cobalamin (vitamin B12) do so via unique pathways depending on the presence of oxygen in the environment. The anaerobic biosynthesis pathway of 5,6-dimethylbenzimidazole, the so-called lower ligand to the cobalt center, has been recently identified. This process begins with the conversion of 5-aminoimidazole ribotide (AIR) to 5-hydroxybenzimidazole (HBI) by the radical S-adenosyl-l-methionine (SAM) enzyme BzaF, also known as HBI synthase. In this work we report the characterization of a radical intermediate in the reaction of BzaF using electron paramagnetic resonance spectroscopy. Using various isotopologues of AIR, we extracted hyperfine parameters for a number of nuclei, allowing us to propose plausible chemical compositions and structures for this intermediate. Specifically, we find that an aminoimidazole radical is formed in close proximity to a fragment of the ribose ring. These findings induce the revision of past proposed mechanisms and illustrate the ability of radical SAM enzymes to tightly control the radical chemistry that they engender
1-(Alkylsulfonic)-3-methylimidazolium chloride BrÖnsted acidic ionic liquid catalyzed hydrogen peroxide oxidations of biomass derived furan aldehydes
No full text5-Hydroxymethylfurfural was converted to succinic anhydride in 90–92% yield by oxidation with 30% hydrogen peroxide using 10 mol% 1-(alkylsulfonic)-3-methylimidazolium chloride acidic ionic liquid catalysts at 60 °C for 14 h. The acidic ionic liquid catalyst could be reused for four catalytic cycles without appreciable loss in catalytic activity. On the other hand oxidation of furfural under similar ionic liquid catalyzed conditions produced a mixture of three products: 2(5H)-furanone, succinic anhydride and maleic acid in 68, 8 and 12% yields respectively
Synthesis and characterization of Zinc/Chitosan-Folic acid complex
No full textTherapeutic drug delivery systems using polymeric materials is an emerging field of research. However, the use of certain polymers has gained much-needed attention by the researchers due to their low toxic nature. In recent years, chitosan has gained popularity as a potential biodegradable polymer that can be used as a component in drug delivery systems. In this study, we synthesized a chitosan derivative that is composed of both folic acid and zinc and may serve as a viable component of a drug delivery system. The results of Fourier Transform Infrared Spectroscopy (FTIR), solid-state 13C Nuclear Magnetic Resonance Spectroscopy (NMR) and UV-visible Spectroscopy demonstrated a substantial difference between chitosan and ZnS/Chitosan-Folic acid derivative. The results were also confirmed using Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM-EDS) techniques. The average particle size of the ZnS/Chitosan-Folic acid system was measured to be 463.67 ± 5.76 nm, showing that the product is within the nano-size range
Profit Analysis of a Two Unit Cold Standby System Operating Under Different Weather Conditions Subject t o Inspection
Get PDFA system, or unit, is said to be working under normal weather conditions if the system is working under prescribed conditions as defined/stated by the definition of reliability of system/unit, otherwise the system is said to be working in abnormal weather conditions. For example, if a car with the capacity for five persons is carrying more than five persons, it will be said to be working under abnormal weather conditions. Another example, if a hydraulic machine having the capacity to lift a maximum weight of 500 tons is lifting a weight of 600 tons, then the machine is working under abnormal weather conditions. Hence, in this situation, work done by the machine is out of its capacity and the machine is working in abnormal weather conditions. If the machine is working within the capacity of the stated conditions, it is said to be working in normal weather conditions. The main purpose of this paper is to analyze the profit of a two-unit system called the standby system that is working under different weather conditions in an inspection facility. There is a single perfect server who visits the system immediately whenever required. A server inspects the unit before repair/replacement of the failed unit. All the mechanical activities done by the server are only possible during normal weather conditions. There are two possibilities after inspection of the unit; either repair of the unit is feasible or not feasible. If repair of the unit is not feasible, then the unit will be replaced immediately by a new unit. Otherwise, the repaired unit works as a new unit. The operative unit undergoes preventive maintenance after a specific (maximum) operation time. All random variables are statistically independent. The failure rate and the rate by which the system undergoes for preventive maintenance are constant whereas the inspection rate, repair rate, and maintenance rate follow negative exponential distributions. The expressions for several reliability measures are derived in steady state conditions using the regenerative point technique and semi-Markov process. The graphical behavior of MTSF, availability and profit function, has been depicted with respect to preventive maintenance rate for arbitrary values of other parameters and costs
Thermoelastic stress analysis of a functionally graded transversely isotropic hollow cylinder in elliptical coordinates
Get PDFThis paper is concerned with the axisymmetric thermoelastic problem to investigate the influence of nonlinear heat conduction equation, displacement functions and thermal stresses of a functionally graded transversely isotropic hollow cylinder that is presented in the elliptical coordinate system. The method of integral transform technique is used to produce an exact solution of the heat conduction equation in which sources are generated according to a linear function of the temperature. An explicit exact solution of the governing thermoelastic equation is proposed when material properties are power-law functions with the exponential form of the radial coordinate. Numerical calculations are also carried out for Material I with the nearly isotropic feature, along with Material II as an anisotropic material and illustrated graphically. The validity of the solution is demonstrated by comparing with the previous results
Parameter Estimation and Optimal Control of the Dynamics Of Transmission of Tuberculosis with Application to Cameroon
Get PDFThis paper deals with the problem of parameter estimation and optimal control of a tuberculosis (TB) model with seasonal fluctuations. We first present a uncontrolled TB model with seasonal fluctuations. We present the theoretical analysis of the uncontrolled TB model without seasonal fluctuations. After, we propose a numerical study to estimate the unknown parameters of the TB model with seasonal fluctuations according to demographic and epidemiological data from Cameroon. Simulation results are in good accordance with the seasonal variation of the new active reported cases of TB in Cameroon. Using this TB model with seasonality, the tuberculosis control is formulated and solved as an optimal control problem, indicating how control terms on the chemoprophylaxis and treatment should be introduced in the considered TB model to reduce the number of individuals with active TB. Results provide a framework for designing cost-effective strategies for TB with two strategies of intervention