Time-dependent Robin boundary conditions in the dynamical Casimir effect

Motivated by experiments in which moving boundaries are simulated by time-dependent properties of static systems, we discuss the model of a massless scalar field submitted to a time-dependent Robin boundary condition (BC) at a static mirror in 1+1 dimensions. Using a perturbative approach, we compute the spectral distribution of the created particles and the total particle creation rate, considering a thermal state as the initial field state.Comment: 10 pages, 3 figures. To appear in proceedings of Conference on Quantum Field Theory under the Influence of External Condition

Jacobian Ensembles Improve Robustness Trade-offs to Adversarial Attacks

Deep neural networks have become an integral part of our software infrastructure and are being deployed in many widely-used and safety-critical applications. However, their integration into many systems also brings with it the vulnerability to test time attacks in the form of Universal Adversarial Perturbations (UAPs). UAPs are a class of perturbations that when applied to any input causes model misclassification. Although there is an ongoing effort to defend models against these adversarial attacks, it is often difficult to reconcile the trade-offs in model accuracy and robustness to adversarial attacks. Jacobian regularization has been shown to improve the robustness of models against UAPs, whilst model ensembles have been widely adopted to improve both predictive performance and model robustness. In this work, we propose a novel approach, Jacobian Ensembles-a combination of Jacobian regularization and model ensembles to significantly increase the robustness against UAPs whilst maintaining or improving model accuracy. Our results show that Jacobian Ensembles achieves previously unseen levels of accuracy and robustness, greatly improving over previous methods that tend to skew towards only either accuracy or robustness

Nonlinear Relativistic and Quantum Equations with a Common Type of Solution

Generalizations of the three main equations of quantum physics, namely, the Schr\"odinger, Klein-Gordon, and Dirac equations, are proposed. Nonlinear terms, characterized by exponents depending on an index $q$, are considered in such a way that the standard linear equations are recovered in the limit $q \rightarrow 1$. Interestingly, these equations present a common, soliton-like, travelling solution, which is written in terms of the $q$-exponential function that naturally emerges within nonextensive statistical mechanics. In all cases, the well-known Einstein energy-momentum relation is preserved for arbitrary values of $q$

Colorblind and multicultural diversity strategies create identity management pressure

This is the final version. Available on open access from Wiley via the DOI in this recordColorblind and multicultural diversity strategies may create identity management pressure, leading minorities to assert or distance from their racial identity. In two experiments (N = 307, 279), Asian participants in the US completed racial identification measures, contemplated employment at a company expressing a multicultural, colorblind, or control strategy, and completed measures assessing ingroup similarity and comfort in the company. In the colorblind condition, those strongly identified with their racial ingroup downplayed similarity to the ingroup and expressed less comfort relative to multicultural and control conditions. Those weakly identified reported more similarity (but inconsistently) and more comfort in the colorblind relative to multicultural and control conditions. Thus, diversity strategies convey different meanings to strongly and weakly identified Asians, with the former responding to colorblindness with identity distancing and the latter with identity assertion. Multiculturalism does not alter the typical pattern expected, with strongly identified asserting their identity more than weakly identified.Economic and Social Research Council (ESRC

Potential use of chitosan in the control of grapevine trunk diseases

Due to its fungistatic or fungicidal potential, chitosan, a high molecular-weight polymer that is non-toxic and biodegradable, has become an alternative to conventional fungicides. In addition, chitosan is reported to elicit defense mechanisms in plant tissues. In this study, we explored the in vitro fungicidal effect of chitosan on some of the most important grapevine wood fungi, such as Botryosphaeria sp. (dieback and cane blight), Phomopsis sp. (Phomopsis cane and leaf spot), Eutypa lata (eutypa dieback), Neonectria liriodendri (black foot disease), Phaeomoniella chlamydospora (Petri disease and esca) and Fomitiporia sp. (esca). Inhibition of mycelial growth was evaluated at five concentrations 50, 25, 5, 2.5 and 0.5 mg a.i. l-1 of chitosan. Chitosan was effective in reducing mycelial growth of all the fungi. The lowest EC50 values were obtained with Pa. chlamydospora, Fomitiporia sp. and Botryosphaeria sp., and the highest with Neon. liriodendri. All these were inferior to the maximum recommended field rate (8.33 mg a.i. l-1) with exception of the value obtained with Neon. liriodendri. Greenhouse experiments were carried out to evaluate the efficacy of foliar sprays of chitosan on potted grapevine plants (cultivar Castelão) growing in a substrate artificially infested with Pa. chlamydospora or Neon. liriodendri. The effect of chitosan against Neon. liriodendri was similar to that achieved with some selected fungicides (carbendazim+flusilazole, cyprodinil+fludioxonil and tebuconazole). Chitosan significantly improved plant growth (plant height and number of roots) and decreased disease incidence compared with untreated plants. As regards Pa. chlamydospora, chitosan only reduced the disease incidence caused by this fungus