The Coherence Field in the Field Perturbation Theory of Superconductivity

We re-examine the Nambu-Gorkov perturbation theory of superconductivity on the basis of the Bogoliubov-Valatin quasi-particles. We show that two different fields (and two additional analogous fields) may be constructed, and that the Nambu field is only one of them. For the other field- the coherence field- the interaction is given by means of two interaction vertices that are based on the Pauli matrices tau1 and tau3. Consequently, the Hartree integral for the off-diagonal pairing self-energy may be finite, and in some cases large. We interpret the results in terms of conventional superconductivity, and also discuss briefly possible implications to HTSC

Hydrogen leak detection device Patent

Development of device for detecting hydrogen in ambient environment

Sniffer used as portable hydrogen leak detector

Sniffer type portable monitor detects hydrogen in air, oxygen, nitrogen, or helium. It indicates the presence of hydrogen in contact with activated palladium black by a change in color of a thermochromic paint, and indicates the quantity of hydrogen by a sensor probe and continuous readout

Monte Carlo Planning method estimates planning horizons during interactive social exchange

Reciprocating interactions represent a central feature of all human exchanges. They have been the target of various recent experiments, with healthy participants and psychiatric populations engaging as dyads in multi-round exchanges such as a repeated trust task. Behaviour in such exchanges involves complexities related to each agent's preference for equity with their partner, beliefs about the partner's appetite for equity, beliefs about the partner's model of their partner, and so on. Agents may also plan different numbers of steps into the future. Providing a computationally precise account of the behaviour is an essential step towards understanding what underlies choices. A natural framework for this is that of an interactive partially observable Markov decision process (IPOMDP). However, the various complexities make IPOMDPs inordinately computationally challenging. Here, we show how to approximate the solution for the multi-round trust task using a variant of the Monte-Carlo tree search algorithm. We demonstrate that the algorithm is efficient and effective, and therefore can be used to invert observations of behavioural choices. We use generated behaviour to elucidate the richness and sophistication of interactive inference

Neural Prediction Errors Reveal a Risk-Sensitive Reinforcement-Learning Process in the Human Brain

Humans and animals are exquisitely, though idiosyncratically, sensitive to risk or variance in the outcomes of their actions. Economic, psychological, and neural aspects of this are well studied when information about risk is provided explicitly. However, we must normally learn about outcomes from experience, through trial and error. Traditional models of such reinforcement learning focus on learning about the mean reward value of cues and ignore higher order moments such as variance. We used fMRI to test whether the neural correlates of human reinforcement learning are sensitive to experienced risk. Our analysis focused on anatomically delineated regions of a priori interest in the nucleus accumbens, where blood oxygenation level-dependent (BOLD) signals have been suggested as correlating with quantities derived from reinforcement learning. We first provide unbiased evidence that the raw BOLD signal in these regions corresponds closely to a reward prediction error. We then derive from this signal the learned values of cues that predict rewards of equal mean but different variance and show that these values are indeed modulated by experienced risk. Moreover, a close neurometric–psychometric coupling exists between the fluctuations of the experience-based evaluations of risky options that we measured neurally and the fluctuations in behavioral risk aversion. This suggests that risk sensitivity is integral to human learning, illuminating economic models of choice, neuroscientific models of affective learning, and the workings of the underlying neural mechanisms

Factors influencing patient loyalty to outpatient medical services: an empirical analysis of the UAE’s government healthcare system

Purpose The aim of this research is to uncover issues that inhibit patients' satisfaction and loyalty and identify factors that could enhance customer retention by government hospitals in the United Arab Emirates (UAE). The mediating impact of outpatient satisfaction on service quality, word of mouth (WoM), hospital image, outpatient–physician relationship and outpatient loyalty were tested. Design/methodology/approach The sample data used to test the hypotheses were drawn from a pool of patients served by a government healthcare agency in Abu Dhabi. Questionnaires were provided to 418 participants using methods such as short message service, e-mail and face-to-face delivery. The data were analyzed using SmartPLS 3.3.2 software. Findings The results indicate that service quality, WoM and outpatient–physician relationship positively impact outpatient satisfaction and indirectly effect outpatient loyalty; that hospital image positively impacts outpatient satisfaction and loyalty and has a partially mediating effect on loyalty; that waiting time satisfaction has no effect on outpatient satisfaction and no moderating effect on the outpatient satisfaction–loyalty relationship and that switching cost has a positive effect on loyalty but no moderating effect on the outpatient satisfaction–loyalty relationship. Research limitations/implications The first limitation of this study concerns the fact that only patients who had previously been served by these hospitals' outpatient units were included. Furthermore, the research was not able to obtain extensive findings related to the various factors that negatively impacted patient satisfaction and loyalty among all of the departments of government hospitals, such as inpatient care and emergency care. Practical implications Centered on the findings from this research, increasing switching costs would prevent patients from switching to other healthcare providers. Therefore, it has the potential to create a false loyalty or a hostage customer (Jones and Sasser, 1995). Additionally, making patients feel connected to their treatment plan and engaged in their care by developing a tool to maintain their enthusiasm about their health is important. It is therefore recommended that government hospital care providers and management consider providing online tools that patients can use to self-manage their care. Social implications The results regarding patients' satisfaction level suggest several areas for improvement. The first pertains to waiting area entertainment and comfort because patients indicated that there is not enough entertainment or ways to pass the time when waiting for services. In addition to enhancing the entertainment and comfort of waiting areas, government hospital staff should maintain contact with patients who are waiting to ensure that they are aware of the time they will spend. Another area for improvement is the parking lot. During summer, patients prefer to walk less in the sun, which causes them to seek parking closer to the door. Government hospital management should consider different methods for transporting patients closer to the door, such as golf carts or valet services. Originality/value This is the first study to investigate the mediating impact of outpatients' satisfaction between its antecedents and loyalty in the UAE. These results provide an improved understanding of the factors influencing patient choices and establish more accurate methods for increasing patient loyalty to retain more patients

Quantum lithography by coherent control of classical light pulses

The smallest spot in optical lithography and microscopy is generally limited by diffraction. Quantum lithography, which utilizes interference between groups of N entangled photons, was recently proposed to beat the diffraction limit by a factor N. Here we propose a simple method to obtain N photons interference with classical pulses that excite a narrow multiphoton transition, thus shifting the "quantum weight" from the electromagnetic field to the lithographic material. We show how a practical complete lithographic scheme can be developed and demonstrate the underlying principles experimentally by two-photon interference in atomic Rubidium, to obtain focal spots that beat the diffraction limit by a factor of 2.Comment: 6 pages, 4 figures, Submitted to Opt. Expres

Déni de grossesse, infanticide et justice

International audienc