Solving the paradox of the folded falling chain by considering horizontal kinetic energy and link geometry

A folded chain, with one end fixed at the ceiling and the other end released from the same elevation, is commonly modeled as an energy-conserving system in one-dimension. However, the analytical paradigms in previous literature is unsatisfying: The theoretical prediction of the tension at the fixed end becomes infinitely large when the free end reaches the bottom, contradicting to the experimental observations. Furthermore, the dependence of the total falling time on the link number demonstrated in numerical simulations is still unexplained. Here, considering the horizontal kinetic energy and the geometry of each link, we derived analytical solutions of the maximal tension as well as the total falling time, in agreement with simulation results and experimental data reported in previous studies. This theoretical perspective shows a simple representation of the complicated two-dimensional falling chain system and, in particular, specifies the signature of the chain properties.Comment: 13 pages, 4 figure

Media Richness and User Continuance to Instant Messaging

Media richness determines adoption of information systems. Insufficient research was done for investigating its influence on user continuance of using instant messaging applications. This study used classic IS and psychological theories to construct a research framework. This study gathered more than 200 responses by using an online form. LISREL software was used to conduct structural equation modeling technique to test the research framework. The findings indicated that various but not all dimensions of media richness positively contribute to users’ continuance to use instant messaging applications. Specific dimensions provide insights for managers to design their applications to effectively retain their users

A genome-wide association scan for rheumatoid arthritis data by Hotelling's T2 tests

We performed a genome-wide association scan on the North American Rheumatoid Arthritis Consortium (NARAC) data using Hotelling's T2 tests, i.e., TH based on allele coding and TG based on genotype coding. The objective was to identify associations between single-nucleotide polymorphisms (SNPs) or markers and rheumatoid arthritis. In specific candidate gene regions, we evaluated the performance of Hotelling's T2 tests. Then Hotelling's T2 tests were used as a tool to identify new regions that contain SNPs showing strong associations with disease. As expected, the strongest association evidence was found in the region of the HLA-DRB1 locus on chromosome 6. In the region of the TRAF1-C5 genes, we identified two SNPs, rs2900180 and rs3761847, with the largest and the second largest TH and TG scores among all SNPs on chromosome 9. We also identified one SNP, rs2476601, in the region of the PTPN22 gene that had the largest TH score and the second largest TG score among all SNPs on chromosome 1. In addition, SNPs with the largest TH score on each chromosome were identified. These SNPs may be located in the regions of genes that have modest effects on rheumatoid arthritis. These regions deserve further investigation