Exploring the Moderating Effects of Commitment and Perceived Value of Knowledge in Explaining Knowledge Contribution in Virtual Communities

Motivating people to contribute knowledge to others has become a major challenge in knowledge management. To help understand knowledge contribution in virtual communities (VCs)—a popular area for knowledge sharing, this study investigates individuals’ motivations to contribute knowledge based on the nature of knowledge contribution behavior. In particular, the influences of two key moderating variables which have been neglected in most previous studies are examined. The theoretical model is empirically tested using data collected from 363 VC members. We find that reciprocity, reputation, knowledge self-efficacy, enjoyment in helping others and commitment are key factors of four kinds (egoism, altruism, collectivism and principlism) that significantly and directly influence individuals’ knowledge contribution intention in VCs. Perceived value of knowledge (PVK) is found to be an important moderator of the relationships between reciprocity, enjoyment in helping others and knowledge contribution intention. We confirm that commitment reduces the impact of reputation on knowledge contribution intention. Implications for both researchers and practitioners are discussed

Online Mixed Discrete and Continuous Optimization: Algorithms, Regret Analysis and Applications

We study an online mixed discrete and continuous optimization problem where a decision maker interacts with an unknown environment for a number of $T$ rounds. At each round, the decision maker needs to first jointly choose a discrete and a continuous actions and then receives a reward associated with the chosen actions. The goal for the decision maker is to maximize the accumulative reward after $T$ rounds. We propose algorithms to solve the online mixed discrete and continuous optimization problem and prove that the algorithms yield sublinear regret in $T$. We show that a wide range of applications in practice fit into the framework of the online mixed discrete and continuous optimization problem, and apply the proposed algorithms to solve these applications with regret guarantees. We validate our theoretical results with numerical experiments

Simultaneous Detection of Chlamydia Trachomatis, Neisseria Gonorrhoeae, Ureaplasma Urealyticum by Multiplex PCR-Running

Chlamydia trachomatis (CT), Ureaplasma urealyticum (UU) and Neisseria gonorrhoeae (NG) are the most common pathogens of sexually transmitted infections (STIs), frequently founded in urogenital infections, and showed a criminal role in increasing the risk of potential adverse outcomes. In this study a multiplex PCR assay for the simultaneous detection and accurate identification of 3 clinically relevant pathogens of STIs, i.e., CT, NG and UU in a single tube was developed and evaluated. The limits of detection for the multiplex PCR assay were ~10 copies of DNAs per reaction. This assay has comparable clinical sensitivity to the conventional monoplex real-time PCR assay and considerable potential to be routine molecular diagnostic tool for simultaneous identification of STIs at relatively low cost due to multiplexing

A novel Mo-W interlayer approach for CVD diamond deposition on steel

Steel is the most widely used material in engineering for its cost/performance ratio and coatings are routinely applied on its surface to further improve its properties. Diamond coated steel parts are an option for many demanding industrial applications through prolonging the lifetime of steel parts, enhancement of tool performance as well as the reduction of wear rates. Direct deposition of diamond on steel using conventional chemical vapour deposition (CVD) processes is known to give poor results due to the preferential formation of amorphous carbon on iron, nickel and other elements as well as stresses induced from the significant difference in the thermal expansion coefficients of those materials. This article reports a novel approach of deposition of nanocrystalline diamond coatings on high-speed steel (M42) substrates using a multi-structured molybdenum (Mo) - tungsten (W) interlayer to form steel/Mo/Mo-W/W/diamond sandwich structures which overcome the adhesion problem related to direct magnetron sputtering deposition of pure tungsten. Surface, interface and tribology properties were evaluated to understand the role of such an interlayer structure. The multi-structured Mo-W interlayer has been proven to improve the adhesion between diamond films and steel substrates by acting as an effective diffusion barrier during the CVD diamond deposition

A Quality Control Method Based on an Improved Random Forest Algorithm for Surface Air Temperature Observations

A spatial quality control method, ARF, is proposed. The ARF method incorporates the optimization ability of the artificial fish swarm algorithm and the random forest regression function to provide quality control for multiple surface air temperature stations. Surface air temperature observations were recorded at stations in mountainous and plain regions and at neighboring stations to test the performance of the method. Observations from 2005 to 2013 were used as a training set, and observations from 2014 were used as a testing set. The results indicate that the ARF method is able to identify inaccurate observations; and it has a higher rate of detection, lower rate of change for the quality control parameters, and fewer type I errors than traditional methods. Notably, the ARF method yielded low performance indexes in areas with complex terrain, where traditional methods were considerably less effective. In addition, for stations near the ocean without sufficient neighboring stations, different neighboring stations were used to test the different methods. Whereas the traditional methods were affected by station distribution, the ARF method exhibited fewer errors and higher stability. Thus, the method is able to effectively reduce the effects of geographical factors on spatial quality control

Decreased Filamin b expression regulates trophoblastic cells invasion through ERK/MMP-9 pathway in pre-eclampsia

Objectives: The purpose of this study was to investigate the expression of Filamin b in the placental placenta of patients with early or late onset pre-eclampsia (PE) and its potential effects on the pathophysiology of the disease. Methods and methods: Immunohistochemistry staining, western blot assays and real time PCR were used to detect the expression level of FLN-b. The expression levels of MMP-2, MMP-9 and ERK1/2 proteins from control and FLN-b-silenced JEG-3 cells were also detected by western blot and JEG-3 cell invasion. Results: Compared with normal term pregnancies placentas, the FLN-b expression was significantly lower than that of women with PE, its level in late-onset PE is lower than in early-onset PE. In FLN-b-silenced JEG-3 cells, the protein levels of MMP-2, MMP-9 and phosphorylated ERK1/2 decreased markedly and the number of cells penetrating through the transwell chamber membrane is also greatly reduced. Conclusions: Down-regulation of FLN-b inhibits the ERK/MMP-2 and MMP-9 pathways, leading to trophoblastic invasion disorders in the PE placenta.

Thalamus Segmentation from Diffusion Tensor Magnetic Resonance Imaging

We propose a semi-automatic thalamus and thalamus nuclei segmentation algorithm from Diffusion Tensor Magnetic Resonance Imaging (DT-MRI) based on the mean-shift algorithm. Comparing with existing thalamus segmentation algorithms which are mainly based on K-means algorithm, our mean-shift based algorithm is more flexible and adaptive. It does not assume a Gaussian distribution or a fixed number of clusters. Furthermore, the single parameter in the mean-shift based algorithm supports hierarchical clustering naturally

Lipid levels are inversely associated with infectious and all-cause mortality: international MONDO study results.

Cardiovascular (CV) events are increased 36-fold in patients with end-stage renal disease. However, randomized controlled trials to lower LDL cholesterol (LDL-C) and serum total cholesterol (TC) have not shown significant mortality improvements. An inverse association of TC and LDL-C with all-cause and CV mortality has been observed in patients on chronic dialysis. Lipoproteins also may protect against infectious diseases. We used data from 37,250 patients in the international Monitoring Dialysis Outcomes (MONDO) database to evaluate the association between lipids and infection-related or CV mortality. The study began on the first day of lipid measurement and continued for up to 4 years. We applied Cox proportional models with time-varying covariates to study associations of LDL-C, HDL cholesterol (HDL-C), and triglycerides (TGs) with all-cause, CV, infectious, and other causes of death. Overall, 6,147 patients died (19.2% from CV, 13.2% from infection, and 67.6% from other causes). After multivariable adjustment, higher LDL-C, HDL-C, and TGs were independently associated with lower all-cause death risk. Neither LDL-C nor TGs were associated with CV death, and HDL-C was associated with lower CV risk. Higher LDL-C and HDL-C were associated with a lower risk of death from infection or other non-CV causes. LDL-C was associated with reduced all-cause and infectious, but not CV mortality, which resulted in the inverse association with all-cause mortality