Free Information Flow Benefits Truth Seeking

How can we approach the truth in a society? It may depend on various factors. In this paper, using a well-established truth seeking model, the authors show that the persistent free information flow will bring us to the truth. Here the free information flow is modeled as the environmental random noise that could alter one's cognition. Without the random noise, the model predicts that the truth can only be captured by the truth seekers who own actively perceptive ability of the truth and their believers, while the other individuals may stick to falsehood. But under the influence of the random noise, the authors strictly prove that even there is only one truth seeker in the group, all individuals will finally approach the truth.     

Input-to-State Stability of Switched Nonlinear Delay Systems Based on a Novel Lyapunov-Krasovskii Functional Method

In this paper, the input-to-state stability (ISS) analysis is addressed for switched nonlinear delay systems. By introducing a novel Lyapunov-Krasovskii functional with indefinite derivative and the merging switching signal techniques, some new criteria are established for switched nonlinear delay systems under asynchronous switching, which extends the existing results to the nonlinear systems with switching rules and delays. The ISS problem is also considered under synchronous switching for switched nonlinear systems by employing the similar techniques. Finally, a nonlinear delay model is provided to show the effectiveness of the proposed results.     

Systemic Thinking and Practice Toward Facilitating Inclusive Education: Reflections on a Case of Co-Generated Knowledge and Action in South Africa

This article offers our reflections around a case of facilitating systemic thinking and practice in which the first author of the article (Tlale) interacted with research participants/participant researchers with the intention of strengthening systemic thought and action toward fostering inclusive education in the setting (a rural school in the Eastern Cape in South Africa). We reflect upon the process and also how our engagement was perceived by participants, as expressed in feedback received from them. We point to how Tlale introduced the idea of systemic thinking (to teachers, school management team, school governing body, and a district officer for the district) as tied to the possibility of acting to generate transformation toward a more inclusive educational context for the benefit of the learners at the school in question, thus acting as a systemic mediator on their behalf.     

The Ordering and Replacement Policy for the System with Two Types of Failures

In this paper, the optimal maintenance policy is investigated for a system with stochastic lead time and two types of failures. The system has two types of failures, one type is repairable, when the repairable failure occurs, the system will be repaired by repairman, and the system after repair is not "as good as new". The other type of failure is unrepairable, and when the unrepairable failure occurs the system must be replaced by a new and identical one. The spare system for replacement is available only by order, and the lead time for delivering the spare system is stochastic. The successive survival times of the system form a stochastically decreasing geometric process, the consecutive repair times after failures of the system form a renewal process. By using the renewal process theory and geometric process theory, the explicit expression of the long-run average cost per unit time under ordering policy(N-1) is derived, and the corresponding optimal can be found analytically. Finally,the numerical analyses are given.     

Effect of MWCNT reinforcement on the precipitation-hardening behavior of AA2219

Aluminum alloy matrix composites have found a predominant place in research, and their applications are explored in almost all industries. The aerospace industry has been using precipitation-hardenable alloys in structural applications. However, insufficient literature is available on the influence of multiwalled carbon nanotubes (MWCNTs) on precipitation-hardenable alloy composite materials; thus, this work was designed to elucidate the effect on MWCNT reinforcement on AA2219 with and without precipitation hardening. Reinforcement with MWCNTs has been reported to accelerate precipitation and to achieve greater hardness within a much shorter time. The addition of 0.75wt% MWCNTs resulted in maximal hardness at 90 min, which is approximately 27% of improvement over the maximum hardness achieved by the corresponding monolithic alloy after 10 h of aging. The sample reinforced with 0.75wt% MWCNTs showed an improvement of 82% in hardness by solutionizing and aging compared to that achieved by sintering.     

Combinational electroporation and transplantation approach to studying gene functions in avian embryos

Gene transfection is an indispensable approach for studying gene function since it provides important information on gain- and/or loss-of-function. Chick embryos are also extensively employed for studying bio- logical function since they are easily accessible and can be maintained alive after manipulation. The combination of both techniques presents a powerful approach to under- standing how genes regulate embryo development. Fur- thermore, combining these approaches with tissue transplant techniques make even more attractive for elu- cidate gene function. Electroporation, employing parallelly fashioned electrodes, has been widely used in chick embryos. However, experimenters have been frustrated by unsuccessfully transfection in some embryonic tissue of interest because the electrodes were improperly positioned.We presently demonstrated the different patterns of orga- nizing and positioning the electrodes, in combination with tissue transplantation, to efficiently and specifically trans- fect the chick embryonic head, trunk neural tube, heart tube, somites and neural crest cells with the GFP reporter gene.     

In fl uence of HEPES buffer on the local pH and formation of surface layer during in vitro degradation tests of magnesium in DMEM

The human body is a buffered environment where p H is effectively maintained. HEPES is a biological buffer often used to mimic the buffering activity of the body in in vitro studies on the degradation behavior of magnesium. However, the influence of HEPES on the degradation behavior of magnesium in the DMEM pseudo-physiological solution has not yet been determined. The research aimed at elucidating the degradation mechanisms of magnesium in DMEM with and without HEPES. The morphologies and compositions of surface layers formed during in vitro degradation tests for 15–3600 s were characterized. The effect of HEPES on the electrochemical behavior and corrosion tendency was determined by performing electrochemical tests. HEPES indeed retained the local p H, leading to intense intergranular/interparticle corrosion of magnesium made from powder and an increased degradation rate. This was attributed to an interconnected network of cracks formed at the original powder particle boundaries and grain boundaries in the surface layer, which provided pathways for the corrosive medium to interact continuously with the internal surfaces and promoted further dissolution. Surface analysis revealed significantly reduced amounts of precipitated calcium phosphates due to the buffering activity of HEPES so that magnesium became less well protected in the buffered environment.     

A novel GEL-OHA/HAp bone substitute

Self-crosslinked gelatin-oxidized hyaluronic acid/ hydroxyapatite (GEL-OHA/HAp) composite bone substitute was successfully prepared with a novel in situ precipitation method without using any toxic chemical cross-linkers, and its characterizations, including elemental composition, surface morphology, crystallinity, and structure of crystalline phase, were carried out. In order to evaluate its corresponding performances, comparisons with glutaraldehyde crosslinked gelatin/hydroxyapatite (GEL-Glu/ HAp) composite were made in detail. The results indicate that nano-HAp crystallites are homogeneously dispersed in both GEL-OHA/HAp and GEL-Glu/HAp composites, and the HAp crystallites in the former take larger particle size than those in the latter. Mechanical property tests show the acceptable mechanical strength at high strain of GEL-OHA/HAp composite. Study of in vitro degradation and swelling demonstrate that the two composites have similar degradation rate and water absorption capability. By in vitro cell culture, it has been found out that the cells on the GEL-OHA/HAp composite show higher proliferative potential than the cells on the GEL-Glu/HAp composite. Compared with GEL-Glu/HAp composite, GEL-OHA/HAp composite provides an excellent strategy for preparation of non-toxic bone substitute with acceptable corresponding properties.     

Generalized inverse eigenvalue problem for (<Emphasis Type="Italic">P</Emphasis>,<Emphasis Type="Italic">Q</Emphasis>)-conjugate matrices and the associated approximation problem

In this paper, the generalized inverse eigenvalue problem for the (P,Q)-conjugate matrices and the associated approximation problem are discussed by using generalized singular value decomposition (GSVD). Moreover, the least residual problem of the above generalized inverse eigenvalue problem is studied by using the canonical correlation decomposition (CCD). The solutions to these problems are derived. Some numerical examples are given to illustrate the main results.