Data Visualization in Online Educational Research

This chapter presents a general and practical guideline that is intended to introduce the traditional visualization methods (word clouds), and the advanced visualization methods including interactive visualization (heatmap matrix) and dynamic visualization (dashboard), which can be applied in quantitative, qualitative, and mixed-methods research. This chapter also presents the potentials of each visualization method for assisting researchers in choosing the most appropriate one in the web-based research study. Graduate students, educational researchers, and practitioners can contribute to take strengths from each visual analytical method to enhance the reach of significant research findings into the public sphere. By leveraging the novel visualization techniques used in the web-based research study, while staying true to the analytical methods of research design, graduate students, educational researchers, and practitioners will gain a broader understanding of big data and analytics for data use and representation in the field of education

Convergence analysis of variable steps BDF2 method for the space fractional Cahn-Hilliard model

An implicit variable-step BDF2 scheme is established for solving the space fractional Cahn-Hilliard equation, involving the fractional Laplacian, derived from a gradient flow in the negative order Sobolev space $H^{-\alpha}$, $\alpha\in(0,1)$. The Fourier pseudo-spectral method is applied for the spatial approximation. The proposed scheme inherits the energy dissipation law in the form of the modified discrete energy under the sufficient restriction of the time-step ratios. The convergence of the fully discrete scheme is rigorously provided utilizing the newly proved discrete embedding type convolution inequality dealing with the fractional Laplacian. Besides, the mass conservation and the unique solvability are also theoretically guaranteed. Numerical experiments are carried out to show the accuracy and the energy dissipation both for various interface widths. In particular, the multiple-time-scale evolution of the solution is captured by an adaptive time-stepping strategy in the short-to-long time simulation

The Blueshift Of Civ Broad Emission Line In Qsos

For the sample from Ge et al. of 87 low-$z$ Palomar--Green (PG) quasi-stellar objects (QSOs) and 130 high-$z$ QSOs ($0<z<5$) with \hb-based single-epoch supermassive black hole (SMBH) masses, we performed a uniform decomposition of the \civ\ $\lambda$1549 broad-line profile. Based on the rest frame defined by the \oiii $\lambda$5007 narrow emission line, a medium-strong positive correlation is found between the \civ\ blueshift and the luminosity at 5100\AA\ or the Eddington ratio \leddR. A medium-strong negative relationship is found between the \civ\ blueshift and \civ\ equivalent width. These results support the postulation where the radiation pressure may be the driver of \civ\ blueshift. There is a medium strong correlation between the mass ratio of \civ-based to \hb-based \mbh and the \civ\ blueshift, which indicates that the bias for \civ-based \mbh is affected by the \civ\ profile.Comment: 18 pages, 8 figures, Accepted for publication in A

Bright broad-band afterglows of gravitational wave bursts from mergers of binary neutron stars

If double neutron star mergers leave behind a massive magnetar rather than a black hole, a bright early afterglow can follow the gravitational wave burst (GWB) even if there is no short gamma-ray burst (SGRB) - GWB association or there is an association but the SGRB does not beam towards earth. Besides directly dissipating the proto-magnetar wind as suggested by Zhang, we here suggest that the magnetar wind could push the ejecta launched during the merger process, and under certain conditions, would reach a relativistic speed. Such a magnetar-powered ejecta, when interacting with the ambient medium, would develop a bright broad-band afterglow due to synchrotron radiation. We study this physical scenario in detail, and present the predicted X-ray, optical and radio light curves for a range of magnetar and ejecta parameters. We show that the X-ray and optical lightcurves usually peak around the magnetar spindown time scale (10^3-10^5s), reaching brightness readily detectable by wide-field X-ray and optical telescopes, and remain detectable for an extended period. The radio afterglow peaks later, but is much brighter than the case without a magnetar energy injection. Therefore, such bright broad-band afterglows, if detected and combined with GWBs in the future, would be a probe of massive millisecond magnetars and stiff equation-of-state for nuclear matter.Comment: ApJ, in pres

Use of Reclaimed Water in China: management issues and strategies

As one of the fastest economic growing country in the world, China faces many water challenges. While there is no magic bullet to solving those challenges, a diversified selection of alternative water resources to help stretch traditional freshwater supplies is one of the optimal solutions. For this reason, the view of managing wastewater is moving from safe disposal of the treated product to incorporating it into the water supply. Since reclaimed water is increasingly consider being a valuable resource, the management of reclaimed water is also going to play a significant role in China’s future water management. This paper aims to give an overview of reclaimed water used activities in China and outline some issues arise from the management defect. And the innovative management strategies relevant to the management that put forward in this paper may become a part of the journey towards sustainable management of water resources in China. Key words: Reclaimed water; Historic and modern applications; Issues; Strategie

Antibacterial and Antioxidant Characteristics of Pigments and Coelomic Fluid of Sea Urchin, Echinodermata Mathaei Species, from the Persian Gulf

Background & Aims: Sea urchin immune responses are directly exposed to potentially pathogenic microorganisms and develop defence responses mainly based on immunocytes and humoral factors contained in the coelomic fluid. In addition, the polyhydroxylated 1, 4-naphthoquinone pigments are found to possess excellent antimicrobial, antialgal and antioxidant activities. The present research aimed to study the bioactive potentials (antioxidant, antibacterial and cytotoxic) of coelomic fluid and pigments shells and spines of sea urchin, Echinodermata mathaei species. Methods: The coelomic fluid and pigments shell and spine of sea urchin were isolated using buffered mode and hydrogen chloride (HCl), respectively. Then, antioxidant [reducing power, DPPH radical (1, 1-diphenyl 2-picryhydrazyl) scavenging, and total antioxidant capacity), antibacterial (minimum inhibitory concentration or MIC) and cytotoxic potentials were evaluated. Results: The free cells of the coelomic fluid had the highest activity in the all antioxidant methods, and the coelomocyte lysate had the highest antibacterial activity. All the differences were significant at the level of P < 0.05. Conclusion: The result of this research indicated that coelomic fluid and pigments shell and spine of sea urchin, Echinodermata mathaei species, have potent antioxidant activity and the ability for scavenging cytotoxic effects. This suggests that sea urchin shells and spines, most of which are discarded as waste after removal of gonads, would be a new bioresource for natural antioxidants. Keywords: Antioxidant, Antibacterial, Cytotoxic, Sea urchin, Echinometra mathae

A Model for Type-IIP Supernovae with Medium Recombination Approximation

In this paper, we propose a new light-curve model for Type-IIP supernovae (SNe IIP) with an approximation of medium recombination. Recombination of hydrogen that takes place in the envelope is believed highly affect the light curves of SNe IIP. The propagation of the recombination wave through the expanding envelope is crucial to determine the temperature and the bolometric luminosity. Several approximations were made in previous works to determine the recombination front, which plays a role as the pseudo-photosphere. With the Eddington boundary condition, we let the actual photosphere be the boundary to determine the time evolution of temperature profile of the envelope and calculate the bolometric luminosity. A new approximation on the speed of recombination wave is introduced to get a closer result to the real situation. We abandon the non-self-consistent approximations made in former works and solve the initial hump problem in the previous attempt for the slow recombination approximation. The produced light curves show the necessity of this approximation and fit the observation well.Comment: 14 pages, 10 figures, 5 tables. Submitted to ApJ, welcome for comments

A double neutron star merger origin for the cosmological relativistic fading source PTF11agg?

The Palomar Transient Factory (PTF) team recently reported the discovery of a rapidly fading optical transient source, PTF11agg. A long-lived scintillating radio counterpart was identified, but the search for a high energy counterpart showed negative results. The PTF team speculated that PTF11agg may represent a new class of relativistic outbursts. Here we suggest that a neutron star (NS)-NS merger system with a supra-massive magnetar central engine could be a possible source to power such a transient, if our line of sight is not on the jet axis direction of the system. These systems are also top candidates for gravitational wave sources to be detected in the advanced LIGO/Virgo era. We find that the PTF11agg data could be explained well with such a model, suggesting that at least some gravitational wave bursts due to NS-NS mergers may be associated with such a bright electromagnetic counterpart without a \gamma-ray trigger.Comment: Accepted for publication in ApJ Letter

Polymers for quorum sense interference

The synthetic polymers reported in this thesis are able to bind the small molecule autoinducer-2 (AI-2) in the Quorum Sense (QS) pathways of the marine organism with high affinity, and some of the polymers are also able to sequester rapidly the same bacteria from suspension. Specifically, the Alizarin Red S (AR-S) assay was used to compare binding interactions of boric and boronic acid with diol species, and interactions were further probed by 11B-NMR spectroscopy and Mass spectrometry. Dopamine was considered as a potential AI-2 scavenger for polymeric QS control owing to the high binding affinities for boron. Therefore, poly{N-(3,4-dihydroxyphenethyl) methacrylamide-co-N-[3-(dimethylamino)propyl] methacrylamide} [p(DMAm-c-DMAPMAm)] and poly(3,4-dihydroxy-L-phenylalanine methacrylamide) [p(L-DMAm)] were prepared via Reversible Addition Fragmentation Chain Transfer (RAFT) polymerization and characterized by 1H-NMR spectroscopy. The activities of these catechol polymers and carbohydrate-based poly(β-D-glucosyloxyethyl methacrylate) (p(GlcEMA)) in QS interference was demonstrated by bioluminescence assays with the Vibrio harveyi MM32 strain and by bacterial aggregation experiments. Polymersomes were then investigated as artificial protocells, with a view to establishing polymer vesicle containers as both reservoirs of QS mediated molecules, and of binding QS agents and bacteria. Hydrophobic monomers N-(2-Ethylhexyl) acrylamide [p(2-EHAm)] and N-phenylacrylamide [p(PAm)] were therefore polymerized into block copolymers from p(L-DMAm)-RAFT agents. The membrane permeability of polymersomes was measured via encapsulation and release of dyes, while the morphologies were examined with Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM). Polymersomes were also investigated for potency in QS quenching via the bioluminescence assay and bacterial aggregation experiments. Initial studies of a communication feedback loop between bacteria and polymersome-encapsulated QS agents were performed again via bioluminescence assays. The results reveal that the investigated polymersomes exhibit potent activities in QS quenching, and further development might act as components of a synthetic biology approach to combating microbial pathogenicity