Low-mass dark matter search results from full exposure of PandaX-I experiment

We report the results of a weakly-interacting massive particle (WIMP) dark matter search using the full 80.1\;live-day exposure of the first stage of the PandaX experiment (PandaX-I) located in the China Jin-Ping Underground Laboratory. The PandaX-I detector has been optimized for detecting low-mass WIMPs, achieving a photon detection efficiency of 9.6\%. With a fiducial liquid xenon target mass of 54.0\,kg, no significant excess event were found above the expected background. A profile likelihood analysis confirms our earlier finding that the PandaX-I data disfavor all positive low-mass WIMP signals reported in the literature under standard assumptions. A stringent bound on the low mass WIMP is set at WIMP mass below 10\,GeV/c$^2$, demonstrating that liquid xenon detectors can be competitive for low-mass WIMP searches.Comment: v3 as accepted by PRD. Minor update in the text in response to referee comments. Separating Fig. 11(a) and (b) into Fig. 11 and Fig. 12. Legend tweak in Fig. 9(b) and 9(c) as suggested by referee, as well as a missing legend for CRESST-II legend in Fig. 12 (now Fig. 13). Same version as submitted to PR

Regulation of pH During Amelogenesis

During amelogenesis, extracellular matrix proteins interact with growing hydroxyapatite crystals to create one of the most architecturally complex biological tissues. The process of enamel formation is a unique biomineralizing system characterized first by an increase in crystallite length during the secretory phase of amelogenesis, followed by a vast increase in crystallite width and thickness in the later maturation phase when organic complexes are enzymatically removed. Crystal growth is modulated by changes in the pH of the enamel microenvironment that is critical for proper enamel biomineralization. Whereas the genetic bases for most abnormal enamel phenotypes (amelogenesis imperfecta) are generally associated with mutations to enamel matrix specific genes, mutations to genes involved in pH regulation may result in severely affected enamel structure, highlighting the importance of pH regulation for normal enamel development. This review summarizes the intra- and extracellular mechanisms employed by the enamel-forming cells, ameloblasts, to maintain pH homeostasis and, also, discusses the enamel phenotypes associated with disruptions to genes involved in pH regulation

A Mode Switching Extended Kalman Filter for Real-Time Traffic State and Parameter Estimation

Traffic state estimators (TSEs) based on the cell transmission model (CTM) are vulnerable to biased initial estimates of traffic flow parameters, in particular the critical density. For example, an overestimated (underestimated) initial estimate of critical density can cause a delayed (premature) switching of a TSE from free-flow working mode to congestion working mode, hence distorting estimates of traffic states. Only augmenting the traffic flow parameters into the state vector cannot resolve the issue of biased initial estimate of the critical density, because the critical density is unobservable under free-flow mode. To overcome this issue, this paper proposes an innovative supervisory observer to inform the TSE of correct instants for mode switching. In particular, the proposed supervisory observer requires no a priori knowledge of any traffic flow parameter. The idea is to make decisions for mode switching through capturing anomalies in the residuals of the extended Kalman filter (EKF) of the TSE. This paper also proposes, for the first time in relevant literature, to augment capacity drop proportion into state vector so that its value can be calibrated online. Simulation experiments show that the proposed method can correctly capture mode switching times and generate satisfactory estimates of traffic states and track time-varying traffic flow parameters