GeV Scale Asymmetric Dark Matter from Mirror Universe: Direct Detection and LHC Signatures

Mirror universe is a fundamental way to restore parity symmetry in weak interactions. It naturally provides the lightest mirror nucleon as a unique GeV-scale asymmetric dark matter particle candidate. We conjecture that the mirror parity is respected by the fundamental interaction Lagrangian, and its possible soft breaking arises only from non-interaction terms in the gauge-singlet sector. We realize the spontaneous mirror parity violation by minimizing the vacuum Higgs potential, and derive the corresponding Higgs spectrum. We demonstrate that the common origin of CP violation in the visible and mirror neutrino seesaws can generate the right amount of matter and mirror dark matter via leptogenesis. We analyze the direct detections of GeV-scale mirror dark matter by TEXONO and CDEX experiments. We further study the predicted distinctive Higgs signatures at the LHC.Comment: 16pp. Plenary talk presented by HJH at the International Symposium on Cosmology and Particle Astrophysics (CosPA2011). To appear in the conference proceedings of IJMP. Minor refinement

High-precision hydraulic pressure control based on linear pressure-drop modulation in valve critical equilibrium state

High precision and fast response are of great significance for hydraulic pressure control in automotive braking systems. In this paper, a novel sliding mode control based high-precision hydraulic pressure feedback modulation is proposed. Dynamical models of the hydraulic brake system including valve dynamics are established. An open loop load pressure control based on the linear relationship between the pressure-drop and coil current in valve critical open equilibrium state is proposed, and also experimentally validated on a hardware-in-the-loop test rig. The control characteristics under different input pressures and varied coil currents are investigated. Moreover, the sensitivity of the proposed modulation on valve's key structure parameters and environmental temperatures are explored with some unexpected drawbacks. In order to achieve better robustness and precision, a sliding mode control based closed loop scheme is developed for the linear pressure-drop modulation. Comparative tests between this method and the existing methods are carried out. The results validate the effectiveness and superior performance of the proposed closed loop modulation method

A comprehensive analysis of Fermi Gamma-Ray Burst Data: IV. Spectral lag and Its Relation to Ep Evolution

The spectral evolution and spectral lag behavior of 92 bright pulses from 84 gamma-ray bursts (GRBs) observed by the Fermi GBM telescope are studied. These pulses can be classified into hard-to-soft pulses (H2S, 64/92), H2S-dominated-tracking pulses (21/92), and other tracking pulses (7/92). We focus on the relationship between spectral evolution and spectral lags of H2S and H2S-dominated-tracking pulses. %in hard-to-soft pulses (H2S, 64/92) and H2S-dominating-tracking (21/92) pulses. The main trend of spectral evolution (lag behavior) is estimated with $\log E_p\propto k_E\log(t+t_0)$ (${\hat{\tau}} \propto k_{\hat{\tau}}\log E$), where $E_p$ is the peak photon energy in the radiation spectrum, $t+t_0$ is the observer time relative to the beginning of pulse $-t_0$, and ${\hat{\tau}}$ is the spectral lag of photons with energy $E$ with respect to the energy band $8$-$25$ keV. For H2S and H2S-dominated-tracking pulses, a weak correlation between $k_{{\hat{\tau}}}/W$ and $k_E$ is found, where $W$ is the pulse width. We also study the spectral lag behavior with peak time $t_{\rm p_E}$ of pulses for 30 well-shaped pulses and estimate the main trend of the spectral lag behavior with $\log t_{\rm p_E}\propto k_{t_p}\log E$. It is found that $k_{t_p}$ is correlated with $k_E$. We perform simulations under a phenomenological model of spectral evolution, and find that these correlations are reproduced. We then conclude that spectral lags are closely related to spectral evolution within the pulse. The most natural explanation of these observations is that the emission is from the electrons in the same fluid unit at an emission site moving away from the central engine, as expected in the models invoking magnetic dissipation in a moderately-high-$\sigma$ outflow.Comment: 58 pages, 11 figures, 3 tables. ApJ in pres

Rutin has anti-asthmatic effects in an ovalbumin-induced asthmatic mouse model

Purpose: To investigate the anti-asthmatic effects of the flavonoid rutin in an ovalbumin (OVA)-induced asthmatic mouse model.Methods: Asthma was induced by OVA induction. Effects of rutin (25–100 mg/kg BW) on interleukins (IL)-4, IL-5, and IL-13 and interferon (IFN)-γ in bronchoalveolar lavage fluid (BALF) and serum OVAspecific IgE levels were assessed by enzyme linked immunosorbent assay (ELISA). Airway hyperresponsiveness (AHR) was measured by determining lung compliance and airway resistance. Expression levels of p-I-κBα, p-NF-κB p65, TNF-α, and Foxp3 were also assessed. The CD4+ CD25+ Foxp3+ T regulatory cell population was determined by flow cytometry.Results: Rutin significantly (p < 0.05) decreased Th2 cytokines (IL-4, IL-5, IL-13), whereas it enhanced IFN-γ levels in BALF. Decreased OVA-specific serum IgE was also observed with improved lung histology. Rutin was effective in reducing AHR and regulating the expression levels of p-I-κBα, p-NF-κB p65, and TNF α, and also increased the CD4+ CD25+ Foxp3+ Treg cell population and Foxp3 mRNA and protein levels.Conclusion: Rutin effectively suppresses OVA-induced asthma and improves airway function by suppressing inflammatory mediators and inflammatory cell infiltration.Keywords: Asthma, CD4+ CD25+, Cytokines, Inflammation, Ovalbumin, Rutin, Protein level

Influence of surface run-out on disc brake squeal

As a complicated phenomenon of friction-induced noise, disc brake squeal has remained a challenge to automotive industry. To investigate the intermittent characteristics of disc brake squeal, a three-degree-of-freedom dynamics model considering both the friction coefficient and the disc surface run-out (SRO) is established in this paper. Their influences on system complex eigenvalues and transient responses are numerically investigated. At the same time, an experiment is conducted based on a pin-on-disc setup. The experimental results show that disc brake squeal is mainly dependent on modal coupling, and influenced by the incline angle of disc SRO. When disc brake squeal occurs, the time history of sound pressure is consistent with that of the disc vibration, which is due to the synchronization of the incline angle of macro and micro disc SRO that has the equivalent effect on system stability as friction coefficient does

1,25-hydroxyvitamin D relieves colitis in rats via downregulation of toll-like receptor 9 expression

Aim To investigate the therapeutic and immunoregulatory effects of 1,25-dihydroxyvitamin D (1,25(OH)D3) on 2,4,6- trinitrobenzenesulfonic acid (TNBS) -induced colitis in rats. Methods Experimental colitis induced by enema administration of TNBS plus ethanol was treated with 5-aminosalicylic acid (5-ASA) and/or 1,25(OH)D3. Disease activity was measured using the disease activation index (DAI), colon macroscopic damage index (CMDI), histological colonic damage score, and myeloperoxidase (MPO) activity. The expression of toll-like receptor 9 (TLR9) in the colon was determined by reverse transcription-polymerase chain reaction and immunohistochemistry. Results Rats with TNBS-induced colitis had significantly elevated DAI, CMDI, histological colonic damage score, and MPO activity (all P < 0.001) compared to rats without colitis. Treatment with 5-ASA or 1,25(OH)D3 ameliorated colitis by lowering CMDI (P = 0.049, P = 0.040, respectively), histological colonic damage score (P = 0.010, P = 0.005, respectively), and MPO activity (P = 0.0003, P = 0.0013, respectively) compared with the TNBS group. Combined treatment with 5-ASA and 1,25(OH)D3 significantly decreased MPO activity (P = 0.003). 1,25(OH)D3 attenuated colitis without causing hypercalcemia or renal insufficiency. TNBS significantly increased the number of TLR9 positive cells compared to control (P < 0.010), while 5-ASA, 1,25(OH)D3, and combined treatment with 5-ASA and 1,25(OH)D3 significantly decreased it compared to TNBS group (all P < 0.010). In TNBS group a moderate correlation was observed between MPO activity and the number of TLR9-positive cells (r = 0.654, P < 0.001). Conclusion TLR9 expression correlates with the extent of inflammation in TNBS-induced colitis. 1,25(OH)D3 relieves this inflammation possibly by decreasing TLR9 expression