Non-Markovian effect on the quantum discord

We study the non-Markovian effect on the dynamics of the quantum discord by exactly solving a model consisting of two independent qubits subject to two zero-temperature non-Markovian reservoirs, respectively. Considering the two qubits initially prepared in Bell-like or extended Werner-like states, we show that there is no occurrence of the sudden death, but only instantaneous disappearance of the quantum discord at some time points, in comparison to the entanglement sudden death in the same range of the parameters of interest. It implies that the quantum discord is more useful than the entanglement to describe quantum correlation involved in quantum systems.Comment: 5 pages, 5 figure

Si/SiGe quantum dot with superconducting single-electron transistor charge sensor

We report a robust process for fabrication of surface-gated Si/SiGe quantum dots (QDs) with an integrated superconducting single-electron transistor (S-SET) charge sensor. A combination of a deep mesa etch and AlOx backfill is used to reduce gate leakage. After the leakage current is suppressed, Coulomb oscillations of the QD and the current-voltage characteristics of the S-SET are observed at a temperature of 0.3 K. Coupling of the S-SET to the QD is confirmed by using the S-SET to perform sensing of the QD charge state.Comment: 4 pages, 3 figure

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

Analysis of the influence of recent reforms in China : cardiovascular and cerebrovascular medicines as a case history to provide future direction

Background: Pharmaceutical expenditure has grown by 16% per annum in China, enhanced by incentives for physicians and hospitals. Hospital pharmacies dispense 80% of medicines in China, accounting for 46% of total hospital expenditure. Principal measures to moderate drug expenditure growth include pricing initiatives as limited demand-side measures. Objective: Assess current utilization and expenditure including traditional Chinese medicines (TCMs) between 2006 and 2012. Methods: Uncontrolled retrospective study of medicines to treat cardiovascular and cerebrovascular diseases in one of the largest hospitals in southwest China. Results: Utilization increased 3.3-fold for cerebrovascular medicines, greatest for TCMs, with expenditure increasing 4.85-fold. Low prices for generics were seen, similar to Europe. However, there was variable utilization of generics at 29-31% of total product volumes in recent years. There continued to be irrationality in prescribing with high use of TCMs, and the utilization of different medicines dropping significantly once they achieved low prices. Conclusion: Prices still have an appreciable impact on utilization in China. Potential measures similar to those implemented among western European countries could improve prescribing rationality and conserve resources

PPO-UE: Proximal Policy Optimization via Uncertainty-Aware Exploration

Proximal Policy Optimization (PPO) is a highly popular policy-based deep reinforcement learning (DRL) approach. However, we observe that the homogeneous exploration process in PPO could cause an unexpected stability issue in the training phase. To address this issue, we propose PPO-UE, a PPO variant equipped with self-adaptive uncertainty-aware explorations (UEs) based on a ratio uncertainty level. The proposed PPO-UE is designed to improve convergence speed and performance with an optimized ratio uncertainty level. Through extensive sensitivity analysis by varying the ratio uncertainty level, our proposed PPO-UE considerably outperforms the baseline PPO in Roboschool continuous control tasks

Abnormal magnetoresistance behavior in Nb thin film with rectangular antidot lattice

Abnormal magnetoresistance behavior is found in superconducting Nb films perforated with rectangular arrays of antidots (holes). Generally magnetoresistance were always found to increase with increasing magnetic field. Here we observed a reversal of this behavior for particular in low temperature or current density. This phenomenon is due to a strong 'caging effect' which interstitial vortices are strongly trapped among pinned multivortices.Comment: 4 pages, 2 figure

Effects of current on nanoscale ring-shaped magnetic tunnel junctions

We report the observation and micromagnetic analysis of current-driven magnetization switching in nanoscale ring-shaped magnetic tunnel junctions. When the electric current density exceeds a critical value of the order of $6\times 10^{6}$A/cm$^2$, the magnetization of the two magnetic rings can be switched back and forth between parallel and antiparallel onion states. Theoretical analysis and micromagnetic simulation show that the dominant mechanism for the observed current-driven switching is the spin torque rather than the current-induced circular Oersted field

Phosphodiesterase-4D Knock-down in the Prefrontal Cortex Alleviates Chronic Unpredictable Stress-Induced Depressive-Like Behaviors and Memory Deficits in Mice

Phosphodiesterase 4 (PDE4) has four isoforms (PDE4A-D) with at least 25 splice variants. PDE4 subtype nonselective inhibitors produce potent antidepressant-like and cognition-enhancing effects via increased intracellular cyclic AMP (cAMP) signaling in the brain. Our previous data have demonstrated that long-form PDE4Ds appear to be involved in these pharmacological properties of PDE4 inhibitors in the normal animals. However, it is not clear whether long-form PDE4Ds are critical for the behaviors and related cellular signaling/neuronal plasticity/neuroendocrine alterations in the depressed animals. In the present study, animals exposed to the chronic unpredictable stress (CUS), a rodent model of depression, exhibited elevated corticosterone, depressive-like behavior, memory deficits, accompanied with decreased cAMP-PKA-CREB and cAMP-ERK1/2-CREB signaling and neuroplasticity. These alterations induced by CUS were reversed by RNA interference (RNAi)-mediated prefrontal cortex long-form PDE4Ds (especially PDE4D4 and PDE4D5) knock-down, similar to the effects of the PDE4 subtype nonselective inhibitor rolipram. Furthermore, these effects of RNAi were not enhanced by rolipram. These data indicate a predominant role of long-form PDE4Ds in the pharmacotherapies of PDE4 inhibitors for depression and concomitant memory deficits. Long-form PDE4Ds, especially PDE4D4 and PDE4D5, appear to be the promising targets for the development of antidepressants with high therapeutic indices

Critical evaluation of the expression of gastrin-releasing peptide in dorsal root ganglia and spinal cord

There are substantial disagreements about the expression of gastrin-releasing peptide (GRP) in sensory neurons and whether GRP antibody cross-reacts with substance P (SP). These concerns necessitate a critical revaluation of GRP expression using additional approaches. Here, we show that a widely used GRP antibody specifically recognizes GRP but not SP. In the spinal cord of mice lacking SP (Tac1 KO), the expression of not only GRP but also other peptides, notably neuropeptide Y (NPY), is significantly diminished. We detected Grp mRNA in dorsal root ganglias using reverse transcription polymerase chain reaction, in situ hybridization and RNA-seq. We demonstrated that Grp mRNA and protein are upregulated in dorsal root ganglias, but not in the spinal cord, of mice with chronic itch. Few GRP(+) immunostaining signals were detected in spinal sections following dorsal rhizotomy and GRP(+) cell bodies were not detected in dissociated dorsal horn neurons. Ultrastructural analysis further shows that substantially more GRPergic fibers form synaptic contacts with gastrin releasing peptide receptor-positive (GRPR(+)) neurons than SPergic fibers. Our comprehensive study demonstrates that a majority of GRPergic fibers are of primary afferent origin. A number of factors such as low copy number of Grp transcripts, small percentage of cells expressing Grp, and the use of an eGFP GENSAT transgenic as a surrogate for GRP protein have contributed to the controversy. Optimization of experimental procedures facilitates the specific detection of GRP expression in dorsal root ganglia neurons