Impact of dissipative effects on the macroscopic evolution of a Vlasov system

Numerical diffusion is introduced by any numerical scheme as soon as small scales fluctuations, generated during the dynamical evolution of a collisionless plasma, become comparable to the grid size. Here we investigate the role of numerical dissipation in collisionless plasma simulations by studying the non linear regime of the two stream instability. We show that the long time evolution of the Vlasov - Poisson system can be affected by the used algorithm.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

Propagation of finite amplitude electrostatic disturbances in an inhomogeneous magnetized plasma

A 1D2V open boundary Vlasov-Ampere code has been implemented with the aim of making a detailed investigation of the propagation of finite amplitude electromagnetic disturbances in an inhomogeneous magnetized plasma. The code is being applied to study the propagation of an externally driven electromagnetic signal, localized at one boundary of the integration interval, through a given equilibrium plasma configuration with inhomogeneous plasma density and magnetic field.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

Strategic Information Transmission in Networks

We introduce a tractable model of cheap talk among players located on networks. In our model, a player can send a message to another player if and only if he is linked to him. We derive a sharp equilibrium and welfare characterization which reveals two basic insights. In equilibrium, the willingness of a player to communicate with a neighbor decreases with the number of opponents who communicate with the neighbor. The ex-ante equilibrium welfare of every player increases not only with the number of truthful reports transmitted in the network, but also when truthful reports are more evenly distributed across players. We apply our findings to the analysis of homophily in communities, to organization design, and to the study of endogenous network formation. Communication across communities decreases as communities become larger, and communication may be asymmetric: From large communities to small ones. In our set up, fully decentralized organizations maximize all players� welfare. Further, decentralized networks, where information may flow asymmetrically, endogenously form in equilibrium. Finally, we introduce the possibility of public communication in networks, and identify conditions under which public communication Pareto dominates private communication.

Low-Cost and Green Fabrication of Polymer Electronic Devices by Push-Coating of the Polymer Active Layers

Because of both its easy processability and compatibility with roll-to-roll processes, polymer electronics is considered to be the most promising technology for the future generation of low-cost electronic devices such as light-emitting diodes and solar cells. However, the state-of-the-art deposition technique for polymer electronics (spin-coating) generates a high volume of chlorinated solution wastes during the active layer fabrication. Here, we demonstrate that devices with similar or higher performances can be manufactured using the push-coating technique in which a poly(dimethylsiloxane) (PDMS) layer is simply laid over a very small amount of solution (less than 1μL/covered cm2), which is then left for drying. Using mm thick PDMS provides a means to control the solvent diffusion kinetics (sorption/retention) and removes the necessity for additional applied pressure to generate the desired active layer thickness. Unlike spin-coating, push-coating is a slow drying process that induces a higher degree of crystallinity in the polymer thin film without the necessity for a post-annealing step. The polymer light-emitting diodes and solar cells prepared by push-coating exhibit slightly higher performances with respect to the reference spin-coated devices, whereas at the same time reduce the amounts of active layer materials and chlorinated solvents by 50 and 20 times, respectively. These increased performances can be correlated to the higher polymer crystallinities obtained without applying a post-annealing treatment. As push-coating is a roll-to-roll compatible method, the results presented here open the path to low-cost and eco-friendly fabrication of a wide range of emerging devices based on conjugated polymer materials

Strategic information transmission networks

We study a model of multi-player communication. Privately informed decision makers have different preferences about the actions they take, and communicate to influence each others' actions in their favor. We prove that the equilibrium capability of any player to send a truthful message to a set of players depends not only on the preference composition of those players, but also on the number of players truthfully communicating with each one of them. We establish that the equilibrium welfare depends not only on the number of truthful messages sent in equilibrium, but also on how evenly truthful messages are distributed across decision makers. © 2013 Elsevier Inc

Linguistic Justice and Analytic Philosophy

The paper investigates whether analytic philosophers who are not native English speaking are subject to linguistic injustice, and in case what kind of injustice that is and whether it is different from the general disadvantage that non-native English speakers meet in a wolrd where English is rapidly becoming the lingua franca

Design of Lanthanide-Based OLEDs with Remarkable Circularly Polarized Electroluminescence

Organic light-emitting diodes (OLEDs) able to directly emit circularly polarized (CP) electroluminescence (CP-OLEDs) are rapidly gaining much interest, due to their possible applications in displays with antiglare filters and 3D displays. Development of more efficient CP-OLEDs can open their use also in point-of-care and personalized diagnostic tools, since CP light alteration can be related to health state of irradiated tissues. In this work it is shown that the performance of chiral europium complex-based CP-OLEDs can be improved both in terms of external quantum efficiency (measured on all the Eu bands) and degree of polarization of emitted photons (as measured by the dissymmetry factor gEL), by proper active layer formulation and through a fine tuning of the architecture of the device. Polarization performances (gEL = −1) are obtained about three times higher than for any other CP-OLED reported so far. Moreover, for the first time, it is shown that the position of the recombination zone (RZ) plays a major role on the polarization outcomes. In order to rationalize these results the level of light polarization is related to the position of the RZ allied with the reflection on the cathode through a simple mathematical model. The values predicted by this model are in qualitative agreement with the experimental ones

Benzothiadiazole-based conjugated polyelectrolytes for interfacial engineering in optoelectronic devices

Abstract Polar semiconducting polymers based on a conjugated polymer backbone endowed with chemically anchored polar groups on the side chains have proved to be particularly interesting as optimization layer at organic/cathode interface in optoelectronic devices. In particular, the pendant phosphonate groups impart water-alcohol solubility allowing easy solution processing, and improve electron injection thanks to both a favorable interfacial dipole of phosphonate groups and an intense coordination interaction between the phosphonate groups and Al cathode. In this work we synthesize alternating fluorene-benzothiadiazole copolymers by proposing a post-polymerization reaction to insert the phosphonate groups. Thanks to this approach it is possible to use standard Suzuki coupling conditions, simplifying the process of synthesis, purification and characterization. The polymer Poly[9,9-bis(6′-diethoxylphosphorylhexyl)-alt-benzothiadiazole] (P2), is tested in conventional organic solar cells as cathode interfacial layers showing, with respect to the control device, an increasing of all the photovoltaic parameters, with a final power conversion efficiency that reaches 5.35% starting from 4.6%. The same trend is observed for multilayered polymer light-emitting diodes with an external quantum efficiency of the P2-based PLED enhanced of 1.5 times with respect to the basic devices with bare Al cathode, and negligible roll-off efficiency. The synergic effects of energy gap modulation and of polar phosphonated pendant functionalities of P2 are compared with the corresponding fluorene-based polar homopolymer. Our results show that, not only a proper selection of side functionalities, but also the tailoring of the energy gap of cathode interfacial materials (CIMs) is a possible effective strategy to engineer cathode of different optoelectronic devices and enhance their performance

St. John's Wort reduces neuropathic pain through a hypericin-mediated inhibition of the protein kinase C γ and ɛ activity

International audienceCurrent pharmacological treatments for neuropathic pain have limited efficacy and severe side-effect limitations. St. John's Wort (SJW) is a medicinal plant, mainly used as antidepressant, with a favourable side-effect profile. We here demonstrate the ability of SJW to relieve neuropathic pain in rat models. The antihyperalgesic profile and mechanism of action of SJW and its main components was studied in two rat models of neuropathic pain: the chronic constriction injury and the repeated administration of oxaliplatin. SJW, acutely administered at low doses (30-60mgkg p.o.), reversed mechanical hyperalgesia with a prolonged effect, being effective up to 180min after injection. Further examinations of the SJW main components revealed that hyperforin and hypericin were responsible for the antihyperalgesic properties whereas flavonoids were ineffective. The effect of SJW on the PKC expression and activation was investigated in the periaqueductal grey (PAG) area by immunoblotting experiments. Mechanistic studies showed a robust over-expression and hyperphosphorylation of the PKC-γ (227.0±15.0% of control) and -ɛ (213.9±17.0) isoforms in the rat PAG area. A single oral administration of SJW produced a significant decrease of the PKC-γ (131.8±10.0) and -ɛ (105.2±12.0) phosphorylation in the PAG area due to the presence of hypericin. Furthermore, SJW showed a dual mechanism of action since hyperforin antinociception involves an opioid-dependent pathway. Rats undergoing treatment with SJW and purified components did not show any behavioural side effects or signs of altered locomotor activity. Our results indicate SJW as a prolonged antihyperalgesic treatment through inhibition of PKC isoforms and their phosphorylation

High-efficiency all-solution-processed light-emitting diodes based on anisotropic colloidal heterostructures with polar polymer injecting layers

Colloidal quantum dots (QDs) are emerging as true candidates for light-emitting diodes with ultrasaturated colors. Here, we combine CdSe/CdS dot-in-rod hetero-structures and polar/polyelectrolytic conjugated polymers to demonstrate the first example of fully solution-based quantum dot light-emitting diodes (QD-LEDs) incorporating all-organic injection/transport layers with high brightness, very limited roll-off and external quantum efficiency as high as 6.1%, which is 20 times higher than the record QD-LEDs with all-solution processed organic interlayers and exceeds by over 200% QD-LEDs embedding vacuum-deposited organic molecules