Effects of SCH23390 and spiperone administered into medial striatum and intermediate medial mesopallium on rewarding effects of morphine in day-old chicks

.In the avian forebrain, the medial striatum and the intermediate medial mesopallium are thought to be important structures for associative learning in chicks, where the role of dopaminergic systems in learning processes has been verified in various behavioral paradigms, such as one-trial passive avoidance learning. However, it is not yet clear whether the dopaminergic system of these regions is responsible for associative learning underlying cue-elicited drug reward. In this study, a 6-day conditioning schedule in day-old chicks with i.p. morphine (2 mg/kg) was used to compare the effects of intracerebrally injected dopamine D(1) receptor antagonist, SCH23390, and D(2) antagonist, spiperone. The antagonists were injected bilaterally (3 mu g/site) into either the medial striatum or the intermediate medial mesopallium, and tests were conducted on morphine-induced conditioned place preference or locomotor activity. The acquisition of place preference was significantly inhibited by SCH23390 in either the medial striatum or the intermediate medial mesopallium, but not by spiperone. However, in the medial striatum, but not in the intermediate medial mesopallium, the locomotor activity was blocked by both SCH23390 and spiperone. These data suggest that the medial striatum and the intermediate medial mesopallium in birds are differentially involved in the rewarding effects of morphine, and similarly to mammals, the dopamine D(1) system may play an important role in the development of opiate reward. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved

Post-Oligarchic Evolution of Protoplanetary Embryos and the Stability of Planetary Systems

We investigate the orbit-crossing time (T_c) of protoplanet systems both with and without a gas-disk background. The protoplanets are initially with equal masses and separation (EMS systems) scaled by their mutual Hill's radii. In a gas-free environment, we find log (T_c/yr) = A+B \log (k_0/2.3). Through a simple analytical approach, we demonstrate that the evolution of the velocity dispersion in an EMS system follows a random walk. The stochastic nature of random-walk diffusion leads to (i) an increasing average eccentricity ~ t^1/2, where t is the time; (ii) Rayleigh-distributed eccentricities (P(e,t)=e/\sigma^2 \exp(-e^2/(2\sigma^2)) of the protoplanets; (iii) a power-law dependence of T_c on planetary separation. As evidence for the chaotic diffusion, the observed eccentricities of known extra solar planets can be approximated by a Rayleigh distribution. We evaluate the isolation masses of the embryos, which determine the probability of gas giant formation, as a function of the dust and gas surface densities.Comment: 15 pages, 13 figures (2 color ones), accepted for publication in Ap

Probability of Error for Optimal Codes in a Reconfigurable Intelligent Surface Aided URLLC System

The lower bound on the decoding error probability for the optimal code given a signal-to-noise ratio and a code rate are investigated in this letter for the reconfigurable intelligent surface (RIS) communication system over a Rician fading channel at the short blocklength regime, which is the key characteristic of ultra-reliable low-latency communications (URLLC) to meet the need for strict adherence to quality of service (QoS) requirements. Sphere packing technique is used to derive our main results. The Wald sequential t-test lemma and the Gaussian-Chebyshev quadrature are the main tools to obtain the closed-form expression for the lower bound. Numerical results are provided to validate our results and demonstrate the tightness of our results compared to the Polyanskiy-Poor-Verdu (PPV) bound

Salvage of Supervision in Weakly Supervised Detection

Weakly supervised object detection (WSOD) has recently attracted much attention. However, the method, performance and speed gaps between WSOD and fully supervised detection prevent WSOD from being applied in real-world tasks. To bridge the gaps, this paper proposes a new framework, Salvage of Supervision (SoS), with the key idea being to harness every potentially useful supervisory signal in WSOD: the weak image-level labels, the pseudo-labels, and the power of semi-supervised object detection. This paper shows that each type of supervisory signal brings in notable improvements, outperforms existing WSOD methods (which mainly use only the weak labels) by large margins. The proposed SoS-WSOD method achieves 64.4 $m\text{AP}_{50}$ on VOC2007, 61.9 $m\text{AP}_{50}$ on VOC2012 and 16.4 $m\text{AP}_{50:95}$ on MS-COCO, and also has fast inference speed. Ablations and visualization further verify the effectiveness of SoS

Modeling UV and X-Ray Emission in a Post-CME Current Sheet

A post-CME current sheet (CS) is a common feature developed behind an erupting flux rope in CME models. Observationally, white light observations have recorded many occurrences of a thin ray appearing behind a CME eruption that closely resembles a post-CME CS in its spatial correspondence and morphology. UV and X-ray observations further strengthen this interpretation by the observations of high temperature emission at locations consistent with model predictions. The next question then becomes whether the properties inside a post-CME CS predicted by a model agree with observed properties. In this work, we assume that the post-CME CS is a consequence of Petschek-like reconnection and that the observed ray-like structure is bounded by a pair of slow mode shocks developed from the reconnection site. We perform time-dependent ionization calculations and model the UV line emission. We find that such a model is consistent with SOHO/UVCS observations of the post-CME CS. The change of Fe XVIII emission in one event implies an inflow speed of ~10 km/s and a corresponding reconnection rate of M_A ~ 0.01. We calculate the expected X-ray emission for comparison with X-ray observations by Hinode/XRT, as well as the ionic charge states as would be measured in-situ at 1 AU. We find that the predicted count rate for Hinode/XRT agree with what was observed in a post-CME CS on April 9, 2008, and the predicted ionic charge states are consistent with high ionization states commonly measured in the interplanetary CMEs. The model results depend strongly on the physical parameters in the ambient corona, namely the coronal magnetic field, the electron density and temperature during the CME event. It is crucial to obtain these ambient coronal parameters and as many facets of the CS properties as possible by observational means so that the post-CME current sheet models can be scrutinized more effectively

Green's function and stability of a linear partial difference scheme

AbstractThis paper is concerned with a linear partial difference equation which arises from discretizing a heat and a first order wave equations. A Green's function for this equation is derived. Various representation theorems, monotonicity, and oscillatory properties of the Green's functions are obtained. Then by means of the representation theorems, we derive several stability criteria for arbitrary solutions of this equation