Online Learning and Academic Cyberloafing

In this study, we developed and tested a model examining the impact of environmental and technological stressors on academic cyberloafing, specifically interactive and noninteractive cyberloafing. We further examined the relationship between cyberloafing and in-class engagement (attention and absorption), as well as the mediating effect of cyberloafing on the relationships between the stressors and engagement. Data were collected through an online survey of 200 undergraduate students from a large university in Asia. Findings showed that only environmental stressor was positively related to interactive cyberloafing. Both stressors were positively related to non-interactive cyberloafing. Interactive cyberloafing was negatively related with, while non-interactive cyberloafing was positively related with engagement. Overall, non-interactive cyberloafing mediated all relationships between the stressors and both dimensions of engagement, while interactive cyberloafing only mediated the relationship between environmental stressor and absorption. Our results suggest that some cyberloafing activities can be rejuvenating for students. Implications for research and practice are discusse

Antioxidant properties of guava fruit : comparison with some local fruits

Two varieties of guava fruit were analyzed for total phenol contents, ascorbic acid contents and antioxidant activities. The antioxidant activities were assessed based on the ability of the fruit extracts in 50% ethanol to scavenge DPPH, reduce Fe(III) to Fe(II) and to bind to Fe(II) ion. The results were compared to several other local fruits as well as orange. It was found that the guava fruit contains relatively high amounts of antioxidant. It also has high primary, but low secondary antioxidant potential. Storage at 4oC has the effect of increasing ascorbic acid content, and the non-peeled fruit has higher total phenol and ascorbic acid contents compared to the peeled fruit. The length and width of the seedy guava were also monitored over a period of 17 weeks to define specific stages of fruit ripening

The freshwater pulse—a numerical model with application to the St. Lawrence Estuary

The freshwater pulse, characterized by a salinity minimum, has been observed in many coastal areas. A 2-D numerical model was developed to investigate the laterally averaged estuarine circulation, and the freshwater pulse in the St. Lawrence Estuary. The effects on the circulation and salinity of various parameters, including vertical eddy coefficients, river runoff, the bottom friction coefficient and the open boundary condition were studied.The freshwater pulse in the St. Lawrence Estuary was simulated using a seasonal variation of the freshwater runoff. In addition to simulating the downstream propagation and the reduction of the pulse\u27s amplitude toward both the ocean and the deep water in most of the areas, several interesting results were produced. These include (I) the finding of the maximum and minimum amplitudes of the pulse, (2) the increase of the amplitude from surface to deep water in the far upstream region, (3) the initial formation of the pulse at two surface locations, (4) the increase of the arrival time from surface to deep water, and (5) the increase of the arrival time for deep water pulses (at 25 m or deeper) toward the slope region where the upstream shallow water and the downstream deep water separates. The responses of the horizonal and vertical velocities to the freshwater pulse were described. Dynamics associated with the distribution, formation and propagation of the pulse were discussed

Membrane Potential Distribution Adjustment and Parametric Surrogate Gradient in Spiking Neural Networks

As an emerging network model, spiking neural networks (SNNs) have aroused significant research attentions in recent years. However, the energy-efficient binary spikes do not augur well with gradient descent-based training approaches. Surrogate gradient (SG) strategy is investigated and applied to circumvent this issue and train SNNs from scratch. Due to the lack of well-recognized SG selection rule, most SGs are chosen intuitively. We propose the parametric surrogate gradient (PSG) method to iteratively update SG and eventually determine an optimal surrogate gradient parameter, which calibrates the shape of candidate SGs. In SNNs, neural potential distribution tends to deviate unpredictably due to quantization error. We evaluate such potential shift and propose methodology for potential distribution adjustment (PDA) to minimize the loss of undesired pre-activations. Experimental results demonstrate that the proposed methods can be readily integrated with backpropagation through time (BPTT) algorithm and help modulated SNNs to achieve state-of-the-art performance on both static and dynamic dataset with fewer timesteps.Comment: 10 pages, 8 figure

Mesenchymal stem cell differentiation on biomimetic surfaces for orthopaedic applications

Ph.DDOCTOR OF PHILOSOPH

High-Throughput Screening Assay In 384-Well Format For The Identification Of Anti-Trypanosomal Agents Against Trypanosoma Brucei Rhodesiense And Mode Of Cell Death Study

In order to accelerate the discovery of novel leads for the treatment of Human African Trypanosomiasis (HAT), it is necessary to have a simple and sensitive assay to identify positive hits by whole cell viability based high-throughput screening (HTS). In this study, the HTS assay was developed in 384-well format using clear plate and black plate, for comparison. Assay robustness and reproducibility were determined under the optimized conditions in 384-well plate was well tolerated in the HTS assay, including percentage of coefficient of variation of 4.68% and 4.74%, signal-to-background ratio of 12.75 and 12.07, and Z’ factor of 0.79 and 0.82 in clear- and black-384-well plate, respectively

Fabrication And Physical Characterisation Of Zinc Oxide Thin Films

Zinc oxide (ZnO) thin films were deposited on α-0001 sapphire substrates using direct current (d.c.) magnetron sputtering process and annealed at various temperatures in an inert atmosphere to investigate its effect on the ultraviolet (UV) emission, stress, lattice constants, crystallite size as well as the possibility of inducing nanostructure growth. Scanning electron microscope (SEM) and X-ray diffraction (XRD) found that ZnO thin films have a fairly uniform granular surface structure with a preferential c-axis growth direction

Spherical Tin Oxide, SnO2 Particles Fabricated via Facile Hydrothermal Method for Detection of Mercury (II) Ions.

Smooth-surface spherical tin oxide particles were fabricated via hydrothermal processing route. X-ray diffraction (XRD) revealed that the particles consisted of the rutile phase of SnO2 with tetragonal structure. The spherical morphology was realized with the aid of ammonia. The aggregation of SnO2 particles could be avoided by adjusting the concentration of tin (II) chloride. Bare glassy carbon electrode (GCE) was modified with the hydrothermally prepared SnO2 particles to detect the presence of mercury (II) ions (Hg2+), in the presence of potassium chloride (KCl) as a supporting electrolyte. GCE modified with the spherical SnO2 particles that possessed small crystallite size and smooth surface exhibited significantly enhanced oxidative and reductive current of Hg2+ during cyclic voltammetry compared with its bare counterpart. The reductive current was observed to increase by two fold and the detection limit of 75 nM for Hg 2+ was achieved. This suggests that SnO2 particles are a promising chemical sensor for the detection of Hg2+ in natural waters

Fabrication of highly ordered TiO2 Nanotubes from Fluoride containing Aqueous Electrolyte by Anodic Oxidation and their Photoelectrochemical response.

The fabrication of TiO2 nanotubes (TNT) was carried out by electrochemical anodization of Ti in aqueous electrolyte containing NH4F. The effect of electrolyte pH, applied voltage, fluoride concentration and anodization duration on the formation of TNT was investigated. It was observed that self-organized TNT can be formed by adjusting the electrolyte to pH 2-4 whereby applied voltage of 10-20 V can be performed to produce highly ordered, well-organized TNT. At 20 V, TNT can be fabricated in the concentration range of 0.07 M to 0.20 M NH4F. Higher fluoride concentration leads to etching of Ti surface and reveals the Ti grain boundaries. The prepared TNT films also show an increase in depth and in size with time and the growth of TNT films reach a steady state after 120 minutes. The morphology and geometrical aspect of the TNT would be an important factor influencing the photoelectrochemical response, with higher photocurrent response is generally associated with thicker layer of TNT. Consequently, one can tailor the resulting TNT to desired surface morphologies by simply manipulating the electrochemical parameters for wide applications such as solar energy conversion and photoelectrocatalysis