HOW DOES AWARENESS OF TASK CONFLICT MOTIVATE WIKI-BASED COLLABORATIVE LEARNING? A DESIGN SCIENCE APPROACH

Lack of motivation is a serious problem in wiki-based collaboration process. The original wiki is designed to hide authorship information. Such design may hinder users from being aware of task conflict, resulting in undesired outcomes (e.g., lack of motivation, and suppressed knowledge exchange activities). This research-in-progress tries to motivate students to participate in wiki-based collaborative learning project by increasing awareness of task conflict. Two tools were proposed to solve problems caused by lack of task conflict clues, such as low level of motivation, content trust, knowledge exchange, and sense of audience. A field test was executed to evaluate new designs. We propose to invite active participants from the field test and use focus group interview to explain how awareness of task conflict motivates participation in collaborative learning. This research-inprogress has the potential to lead to various theoretical and practical implications. For example, the results will enhance the literature on task conflict and user motivation, help platforms design motivation mechanisms

Optimal Design of Bus Stop Locations Integrating Continuum Approximation and Discrete Models

Although transit stop location problem has been extensively studied, the two main categories of modeling methodologies, i.e., discrete models and continuum approximation (CA) ones, seem have little intersection. Both have strengths and weaknesses, respectively. This study intends to integrate them by taking the advantage of CA models’ parsimonious property and discrete models’ fine consideration of practical conditions. In doing so, we first employ the state-of-the-art CA models to yield the optimal design, which serves as the input to the next discrete model. Then, the stop location problem is formulated into a multivariable nonlinear minimization problem with a given number of stop location variables and location constraint. The interior-point algorithm is presented to find the optimal design that is ready for implementation. In numerical studies, the proposed model is applied to a variety of scenarios with respect to demand levels, spatial heterogeneity, and route length. The results demonstrate the consistent advantage of the proposed model in all scenarios as against its counterparts, i.e., two existing recipes that convert CA model-based solution into real design of stop locations. Lastly, a case study is presented using real data and practical constraints for the adjustment of a bus route in Chengdu (China). System cost saving of 15.79% is observed by before-and-after comparison. Document type: Articl

Effects of Dispersal for a Logistic Growth Population in Random Environments

We study a stochastic logistic model with diffusion between two patches in this paper. Using the definition of stationary distribution, we discuss the effect of dispersal in detail. If the species are able to have nontrivial stationary distributions when the patches are isolated, then they continue to do so for small diffusion rates. In addition, we use some examples and numerical experiments to reflect that diffusions are capable of both stabilizing and destabilizing a given ecosystem

General Physical Properties of Gamma-Ray-emitting Radio Galaxies

We study the radio galaxies with known redshift detected by the Fermi satellite after 10 years of data (4FGL-DR2). We use a one-zone leptonic model to fit the quasi-simultaneous multiwavelength data of these radio galaxies and study the distributions of the derived physical parameter as a function of black hole mass and accretion disk luminosity. The main results are as follows. (1) We find that the jet kinetic power of most radio galaxies can be explained by the hybrid jet model based on ADAFs surrounding Kerr black holes. (2) After excluding the redshift, there is a significant correlation between the radiation jet power and the accretion disk luminosity, while the jet kinetic power is weakly correlated with the accretion disk luminosity. (3) We also find a significant correlation between inverse Compton luminosity and synchrotron luminosity. The slope of the correlation for radio galaxies is consistent with the synchrotron self-Compton (SSC) process. The result may suggest that the high-energy component of radio galaxies is dominated by the SSC process.Comment: 9 pages,7 figures, accept for publication in ApJ

The jet formation mechanism of Gamma-ray Narrow-line Seyfert 1 Galaxies

Under the coronal magnetic field, we estimate the maximal jet power of the Blandford-\Znajek (BZ) mechanism, Blandford-\Payne (BP) mechanism, and hybrid model. The jet power of the BZ and Hybrid model mechanisms depends on the spin of a black hole, while the jet power of the BP mechanism does not depend on the spin of a black hole. At high black hole spin, the jet power of the hybrid model is greater than that of the BZ and BP mechanisms. We find that the jet power of almost all gamma-\ray narrow line Seyfert 1 galaxies (gamma-\NLS1s) can be explained by the hybrid model. However, one source with jet power 0.1~\1 Eddington luminosity can not be explained by the hybrid model. We suggest that the magnetic field dragged inward by the accretion disk with magnetization-\driven outflows may accelerate the jets in this gamma-\NLS1.Comment: 9 pages,6 figures,accepted for publication in MNRA

Laser Beam Propagation through Oceanic Turbulence

Using a recently proposed model for the refractive index fluctuations in oceanic turbulence, optical beam propagation through seawater is explored. The model provides an accurate depiction of the ocean through the inclusion of both temperature and salinity fluctuations to the refractive index. Several important statistical characteristics are explored including spatial coherence radius, angle-of-arrival fluctuations, and beam wander. Theoretical values of these parameters are found based on weak fluctuation theory using the Rytov method. The results presented serve as a foundation for the study of optical beam propagation in oceanic turbulence, which may provide an important support for further researches in applications for underwater communicating, imaging, and sensing systems

Hypermethylated gene ANKDD1A is a candidate tumor suppressor that interacts with FIH1 and decreases HIF1α stability to inhibit cell autophagy in the glioblastoma multiforme hypoxia microenvironment.

Ectopic epigenetic mechanisms play important roles in facilitating tumorigenesis. Here, we first demonstrated that ANKDD1A is a functional tumor suppressor gene, especially in the hypoxia microenvironment. ANKDD1A directly interacts with FIH1 and inhibits the transcriptional activity of HIF1α by upregulating FIH1. In addition, ANKDD1A decreases the half-life of HIF1α by upregulating FIH1, decreases glucose uptake and lactate production, inhibits glioblastoma multiforme (GBM) autophagy, and induces apoptosis in GBM cells under hypoxia. Moreover, ANKDD1A is highly frequently methylated in GBM. The tumor-specific methylation of ANKDD1A indicates that it could be used as a potential epigenetic biomarker as well as a possible therapeutic target