Simulation Study on neutrino nucleus cross section measurement in Segmented Detector at Spallation Neutron Source

Knowledge of $\nu_e$-$\mathrm{Fe}/\mathrm{Pb}$ differential cross sections for $\nu_e$ energy below several tens of MeV scale is believed to be crucial in understanding Supernova physics. In a segmented detector at Spallation Neutrino Source, $\nu_e$ energy reconstructed from the electron range measurement is strongly affected because of both multiple scattering and electromagnetic showers occurring along the electron passage in target materials. In order to estimate the effect, a simulation study has been performed with a cube block model assuming a perfect tracking precision. The distortion of energy spectrum is observed to be proportional to the atomic number of target material. Feasibility of unfolding the distorted $\nu_e$ energy spectrum is studied for both Fe and Pb cases. Evaluation of statistical accuracy attainable is therefore provided for a segmented detector.Comment: 6 pages, 6 figures, submitted to Chinese Physics

The reinforcing effects of ethanol within the posterior ventral tegmental area depend on dopamine neurotransmission to forebrain cortico-limbic systems

Ethanol can be self-infused directly into the posterior ventral tegmental area (pVTA) and these effects involve activation of local dopamine neurons. However, the neuro-circuitry beyond the pVTA involved in these reinforcing effects has not been explored. Intra-pVTA microinjection of ethanol increases dopamine release in the nucleus accumbens (NAC), medial prefrontal cortex (mPFC) and ventral pallidum (VP). The present study tested the hypothesis that the reinforcing effects of ethanol within the pVTA involve the activation of dopamine projections from the pVTA to the NAC, VP and mPFC. Following the acquisition of self-infusions of 200 mg% ethanol into the pVTA, either the dopamine D2 receptor antagonist sulpiride (0, 10 or 100 μM) or the D1 receptor antagonist SCH-23390 (0, 10 or 100 μM) was microinjected into the ipsilateral NAC shell (NACsh), NAC core (NACcr), VP or mPFC immediately prior to the self-infusion sessions to assess the involvement of the different dopamine projections in the reinforcing effects of ethanol. Microinjection of each compound at higher concentration into the NACsh, VP or mPFC, but not the NACcr, significantly reduced the responses on the active lever (from 40-50 to approximately 20 responses). These results indicate that activation of dopamine receptors in the NACsh, VP or mPFC, but not the NACcr, is involved in mediating the reinforcing effects of ethanol in the pVTA, suggesting that the 'alcohol reward' neuro-circuitry consist of, at least in part, activation of the dopamine projections from the pVTA to the NACsh, VP and mPFC

Alcohol drinking increases the dopamine-stimulating effects of ethanol and reduces D2 auto-receptor and group II metabotropic glutamate receptor function within the posterior ventral tegmental area of alcohol preferring (P) rats

Repeated local administration of ethanol (EtOH) sensitized the posterior ventral tegmental area (pVTA) to the local dopamine (DA)-stimulating effects of EtOH. Chronic alcohol drinking increased nucleus accumbens (NAC) DA transmission and pVTA glutamate transmission in alcohol-preferring (P) rats. The objectives of the present study were to determine the effects of chronic alcohol drinking by P rats on the (a) sensitivity and response of the pVTA DA neurons to the DA-stimulating actions of EtOH, and (b) negative feedback control of DA (via D2 auto-receptors) and glutamate (via group II mGlu auto-receptors) release in the pVTA. EtOH (50 or 150 mg%) or the D2/3 receptor antagonist sulpiride (100 or 200 μM) was microinjected into the pVTA while DA was sampled with microdialysis in the NAC shell (NACsh). The mGluR2/3 antagonist LY341495 (1 or 10 μM) was perfused through the pVTA via reverse microdialysis and local extracellular glutamate and DA levels were measured. EtOH produced a more robust increase of NACsh DA in the ‘EtOH’ than ‘Water’ groups (e.g., 150 mg% EtOH: to ~ 210 vs 150% of baseline). In contrast, sulpiride increased DA release in the NACsh more in the ‘Water’ than ‘EtOH’ groups (e.g., 200 μM sulpiride: to ~ 190–240 vs 150–160% of baseline). LY341495 (at 10 μM) increased extracellular glutamate and DA levels in the ‘Water’ (to ~ 150–180% and 180–230% of baseline, respectively) but not the ‘EtOH’ groups. These results indicate that alcohol drinking enhanced the DA-stimulating effects of EtOH, and attenuated the functional activities of D2 auto-receptors and group II mGluRs within the pVTA

The reinforcing effects of ethanol within the nucleus accumbens shell involve activation of local GABA and serotonin receptors

Ethanol is reinforcing within the nucleus accumbens shell (NACsh), but the underlying mechanisms remain unclear. Ethanol can potentiate the function of the GABAA, GABAB, and serotonin-3 (5-HT3) receptors. Therefore, the current study tested the hypothesis that activation of these receptors would be involved in the reinforcing effects of ethanol in the NACsh. An intracranial self-administration (ICSA) procedure was used to assess the reinforcing effects of ethanol in the NACsh of alcohol preferring (P) rats. The ICSA consisted of seven sessions: four sessions to establish 150 mg% ethanol self-infusion into the NACsh; sessions 5 and 6 with co-infusion of ethanol plus one concentration of the GABAA antagonist bicuculline (10 or 100 µM), the GABAB antagonist SCH 50911 (50, 75 or 100 µM), or the 5-HT3 receptor antagonist zacopride (10 or 100 µM); and session 7 with 150 mg% ethanol alone. All groups self-infused ethanol into the NACsh and readily discriminated the active from inactive lever during the acquisition sessions. Co-infusion of 100 µM, but not 10 µM, bicuculline or zacopride significantly decreased active responses during sessions 5 and 6. Co-infusion of 75 µM, but not 50 or 100 µM, SCH 50911 significantly attenuated responses for ethanol. Overall, the results suggest that the reinforcing effects of ethanol in the NACsh may be modulated by activation of local GABAA, GABAB and 5-HT3 receptors

The role of the P2X7 receptor on bone loss in a mouse model of inflammation-mediated osteoporosis

In inflammatory autoimmune diseases, bone loss is frequent. In most cases, secondary osteoporosis is caused by treatment with systemic glucocorticoid. However, the pathogenesis behind the bone loss is presumed multifactorial. We aimed to elucidate the role of the P2X7 receptor on bone mineral density (BMD), microarchitecture, and bone strength in a standardized mouse model of inflammation-mediated osteoporosis (IMO). In total 146 mice completed our protocol, 70 wild type (WT) mice and 76 P2X7−/− (knockout, KO). BMD at the femur and spine decreased significantly from baseline to day 20 in the WT IMO mice (p < 0.01). In the WT vehicle, KO vehicle and KO IMO, no significant BMD changes were found. Bone strength showed a lower mid-shaft max strength (p = 0.038) and also a non-significant trend towards lower strength at the femoral neck of the WT IMO group. Trabecular bone volume fraction (BV/TV) and connectivity density (CD) after 20 days were significantly decreased in the WT IMO group (p = 0.001). In contrast, the WT vehicle and KO vehicle, BV/TV and CD did no change at 20 days. Cortical bone revealed no significant microarchitectural changes after 20 days in the WT IMO group, whereas the total cortical area increased significantly in WT vehicle and KO IMO after 20 days (5.2% and 8.8%, respectively). In conclusion, the P2X7 receptor KO mice did not respond to inflammation with loss of BMD whereas the WT mice had a significant loss of BMD, bone strength and trabecular microarchitecture, demonstrating a role for the P2X7 receptor in inflammatory bone loss

Early Cenozoic partial melting of meta-sedimentary rocks of the eastern Gangdese arc, southern Tibet, and its contribution to syn-collisional magmatism

Continental magmatic arcs are characterized by the accretion of voluminous mantle-derived magmatic rocks and the growth of juvenile crust. However, significant volumes of meta-sedimentary rocks occur in the middle and lower arc crust, and the contributions of these rocks to the evolution of arc crust remain unclear. In this paper, we conduct a systematic study of petrology, geochronology, and geochemistry of migmatitic paragneisses from the eastern Gangdese magmatic arc, southern Tibet. The results show that the paragneisses were derived from late Carboniferous greywacke, and underwent an early Cenozoic (69–41 Ma) upper amphibolite-facies metamorphism and partial melting at pressure-temperature conditions of ~11 kbar and ~740 °C, and generated granitic melts with enriched Hf isotopic compositions (anatectic zircon εHf(t) = −10.57 to +0.78). Combined with the existing results, we conclude that the widely distributed meta-sedimentary rocks in the eastern Gangdese arc deep crust have the same protolith ages of late Carboniferous, and record northwestward-decreasing metamorphic conditions. We consider that the deeply buried sedimentary rocks resulted in the compositional change of juvenile lower crust from mafic to felsic and the formation of syn-collisional S-type granitoids. The mixing of melts derived from mantle, juvenile lower crust, and ancient crustal materials resulted in the isotopic enrichment of the syn-collisional arc-type magmatic rocks of the Gangdese arc. We suggest that crustal shortening and underthrusting, and the accretion of mantle-derived magma during the Indo-Asian collision transported the supracrustal rocks to the deep crust of the Gangdese arc

Reduced Levels of mGlu2 Receptors within the Prelimbic Cortex Are Not Associated with Elevated Glutamate Transmission or High Alcohol Drinking

Background A Grm2 cys407* stop codon mutation, which results in a loss of the metabotropic glutamate 2 (mGlu2) receptor protein, was identified as being associated with high alcohol drinking by alcohol-preferring (P) rats. The objectives of the current study were to characterize the effects of reduced levels of mGlu2 receptors on glutamate transmission and alcohol drinking. Methods Quantitative no-net-flux microdialysis was used to test the hypothesis that basal extracellular glutamate levels in the prelimbic (PL) cortex and nucleus accumbens shell (NACsh) will be higher in P than Wistar rats. A lentiviral-delivered short-hairpin RNA (shRNA)-mediated knockdown was used to test the hypothesis that reduced levels of mGlu2 receptors within the PL cortex will increase voluntary alcohol drinking by Wistar rats. A linear regression analysis was used to test the hypothesis that there will be a significant correlation between the Grm2 cys407* mutation and level of alcohol intake. Results Extracellular glutamate concentrations within the PL cortex (3.6 ± 0.6 vs. 6.4 ± 0.6 μM) and NACsh (3.2 ± 0.4 vs. 6.6 ± 0.6 μM) were significantly lower in female P than female Wistar rats. Western blot detected the presence of mGlu2 receptors in these regions of female Wistar rats, but not female P rats. Micro-infusion of shRNAs into the PL cortex significantly reduced local mGlu2 receptor levels (by 40%), but did not alter voluntary alcohol drinking in male Wistar rats. In addition, there was no significant correlation between the Grm2 mutation and alcohol intake in 36 rodent lines (r = 0.29, p > 0.05). Conclusions Collectively, these results suggest a lack of association between the loss of mGlu2 receptors and glutamate transmission in the NACsh and PL cortex of female P rats, and between the level of mGlu2 receptors in the PL cortex and alcohol drinking of male Wistar rats

Crustal evolution of a continental magmatic arc from subduction to collision: a case study in the Gangdese arc, southern Tibetan Plateau

Magmatic arcs are the main environment where continental crust is created on the post-Archean Earth; however, how juvenile arc crust evolves into mature continental crust is still controversial. In this study, we report new bulk-rock major and trace elements, Sr-Nd isotopes, and zircon U-Pb ages and Hf isotopes from a large suite of granites collected from the eastern segment of the Gangdese arc, southern Tibetan Plateau, which record a complete history of arc crust evolution from Mesozoic subduction to Cenozoic collision. These new data show that Gangdese crust-derived granites generated during the subduction to collisional stages record significant geochemical changes with age, indicating that the bulk composition, lithological makeup, and thicknesses of the arc crust evolved over time. Here, we propose that the Gangdese arc had a thick juvenile crust with a small volume of ancient crustal components during late-stage subduction of the Neo-Tethys Ocean, a thin juvenile crust with heterogeneously distributed ancient crustal materials during early collision, and a thick juvenile crust with minor proportions of ancient rocks during late collision. This implies that the arc experienced episodes of crustal thickening during the Late Cretaceous and Eocene, interspersed by periods of thinning during the Paleocene and Miocene, and several discrete episodes of partial melting in the lower arc crust, and cycling or recycling of juvenile and ancient crustal materials within the arc crust and between the crust and mantle. We suggest that shallow subduction of the Neo-Tethys during the Late Cretaceous promoted tectonic thickening of the arc crust, partial melting of lower crust, and formation of high Sr/Y granites. After the onset of the Indo-Asian collision, breakoff of the subducted Neo-Tethyan oceanic slab during the Paleocene/early Eocene allowed thinning of the overlying arc crust and generation of granites derived from juvenile and ancient crustal sources. Continued underthrusting of the Indian continental crust and subsequent delamination of thickened lithospheric mantle led to thickening and thinning of the arc crust, respectively, and partial melting of thickened lower crust and generation of high Sr/Y granites during the Oligocene and Miocene. Using the Gangdese as an analogue for post-Archean continental margins, we suggest that the repeated thickening and thinning of arc crust, and associated multistage remelting of the lower arc crust, and material cycling or recycling within the crust and between the crust and mantle from subduction to collision are common processes that drive maturation of juvenile arc crust

Detecting unambiguously non-Abelian geometric phases with trapped ions

We propose for the first time an experimentally feasible scheme to disclose the noncommutative effects induced by a light-induced non-Abelian gauge structure with trapped ions. Under an appropriate configuration, a true non-Abelian gauge potential naturally arises in connection with the geometric phase associated with two degenerated dark states in a four-state atomic system interacting with three pulsed laser fields. We show that the population in atomic state at the end of a composed path formed by two closed loops $C_1$ and $C_2$ in the parameter space can be significantly different from the composed counter-ordered path. This population difference is directly induced by the noncommutative feature of non-Abelian geometric phases and can be detected unambiguously with current technology.Comment: 6 page