Enhanced surface plasmon polariton propagation induced by active dielectrics

We present numerical simulations for the propagation of surface plasmon polaritons in a dielectric-metal-dielectric waveguide using COMSOL multiphysics software. We show that the use of an active dielectric with gain that compensates metal absorption losses enhances substantially plasmon propagation. Furthermore, the introduction of the active material induces, for a specific gain value, a root in the imaginary part of the propagation constant leading to infinite propagation of the surface plasmon. The computational approaches analyzed in this work can be used to define and tune the optimal conditions for surface plasmon polariton amplification and propagation

Capturing the Shape of Business Cycles with Nonlinear Autoregressive Leading Indicator Models.

This paper studies linear and linear autoregressive leading indicator models of business cycles in OECD countries. The models use the spread between short-term and long-term interest rates as leading indicators for GDP, and their success in capturing business cycles gauged by the non-parametric procedures developed by Harding and Pagan (2001). Our preliminary findings indicate that bivariate nonlinear models of output and the interest rate spread can successfully capture the shape of the business cycle. In particular, they can capture the features of recession and the deviation of the actual path of the cycles from a triangular approximation to this path, both characteristics that other models of GDP fail to reproduce.Business Cycles; Leading Indicators; Nonlinear Models; Yield Spread

Deep Supported Excavation in Difficult Ground Conditions in the City of Patras, Greece — Measured vs. Predicted Behavior

The technical characteristics of a deep supported excavation project using anchored diaphragm walls and the measured (by inclinometers) behavior of the soil retaining system are presented. The measured behavior is then compared with the predicted behavior using a finite element model of the excavation. The comparison shows a good agreement in a location where the soil profile is well defined. However, differences in the magnitude of the displacements were observed when the information on the soil profile was incomplete due to the variability of the deposits on site

Site Dependent Ground Response for the City of Patras, Greece

Results of a preliminary study of seismic ground response at different sites of the coastal city of Patras, in Southern Greece, are presented. At each site equivalent linear 1-D response analyses were conducted by using the finite element program LUSH 2. Values of dynamic properties of soils were obtained from either cross-hole tests or empirical correlations. The \u27rigid base\u27 excitation was selected as to best simulate the expected bedrock motions in Patras from local and distant earthquakes. The results of the analyses indicate a strong differentiation of seismic site response when moving from the coastal region of the city to the inland area. Peak surface accelerations were found to vary from 0.10 g in the coastal region to 0.50 g in the inland area, whereas the corresponding values of spectral acceleration ranged from 0.30 g to 2.0 g. Strong motion records obtained in the city during the July 14, 1993 MS = 5.4 Patras earthquake are in agreement with the results of this study. It is concluded that a systematic microzonation study of Patras would contribute to the seismic protection of the city

Creep Effects on Low-Amplitude Modulus of Clays

The investigation considered effects of on-going or previous drained creep on the low amplitude dynamic shear modulus of normally consolidated artificial and natural clay soils. Resonant column tests using the Hardin and Hall devices determined the low-amplitude shear modulus. Results indicated that the strain-rate of on-going creep determined the kind of effect on shear modulus. High strain-rates produced reduced values whereas low strain-rates slightly increased values of modulus, compared to the no-creep values. Previous creep produced higher values of modulus, when the clay was tested under after-creep isotropic confinement. The rate of secondary increase of shear modulus was not affected by the drained creep action. The behaviors of the remolded kaolinite clay and the undisturbed natural clay were remarkably similar

On the road to somewhere: Brain potentials reflect language effects on motion event perception

Recent studies have identified neural correlates of language effects on perception in static domains of experience such as colour and objects. The generalization of such effects to dynamic domains like motion events remains elusive. Here, we focus on grammatical differences between languages relevant for the description of motion events and their impact on visual scene perception. Two groups of native speakers of German or English were presented with animated videos featuring a dot travelling along a trajectory towards a geometrical shape (endpoint). English is a language with grammatical aspect in which attention is drawn to trajectory and endpoint of motion events equally. German, in contrast, is a non-aspect language which highlights endpoints. We tested the comparative perceptual saliency of trajectory and endpoint of motion events by presenting motion event animations (primes) followed by a picture symbolising the event (target): In 75% of trials, the animation was followed by a mismatching picture (both trajectory and endpoint were different); in 10% of trials, only the trajectory depicted in the picture matched the prime; in 10% of trials, only the endpoint matched the prime; and in 5% of trials both trajectory and endpoint were matching, which was the condition requiring a response from the participant. In Experiment 1 we recorded event-related brain potentials elicited by the picture in native speakers of German and native speakers of English. German participants exhibited a larger P3 wave in the endpoint match than the trajectory match condition, whereas English speakers showed no P3 amplitude difference between conditions. In Experiment 2 participants performed a behavioural motion matching task using the same stimuli as those used in Experiment 1. German and English participants did not differ in response times showing that motion event verbalisation cannot readily account for the difference in P3 amplitude found in the first experiment. We argue that, even in a non-verbal context, the grammatical properties of the native language and associated sentence-level patterns of event encoding influence motion event perception, such that attention is automatically drawn towards aspects highlighted by the grammar

Out Of Control: Overcoming Control-Flow Integrity

As existing defenses like ASLR, DEP, and stack cookies are not sufficient to stop determined attackers from exploiting our software, interest in Control Flow Integrity (CFI) is growing. In its ideal form, CFI prevents flows of control that were not intended by the original program, effectively putting a stop to exploitation based on return oriented programming (and many other attacks besides). Two main problems have prevented CFI from being deployed in practice. First, many CFI implementations require source code or debug information that is typically not available for commercial software. Second, in its ideal form, the technique is very expensive. It is for this reason that current research efforts focus on making CFI fast and practical. Specifically, much of the work on practical CFI is applicable to binaries, and improves performance by enforcing a looser notion of control flow integrity. In this paper, we examine the security implications of such looser notions of CFI: are they still able to prevent code reuse attacks, and if not, how hard is it to bypass its protection? Specifically, we show that with two new types of gadgets, return oriented programming is still possible. We assess the availability of our gadget sets, and demonstrate the practicality of these results with a practical exploit against Internet Explorer that bypasses modern CFI implementations

Harmonic organisation conveys both universal and culture-specific cues for emotional expression in music

Previous research conducted on the cross-cultural perception of music and its emotional content has established that emotions can be communicated across cultures at least on a rudimentary level. Here, we report a cross-cultural study with participants originating from two tribes in northwest Pakistan (Khow and Kalash) and the United Kingdom, with both groups being naïve to the music of the other respective culture. We explored how participants assessed emotional connotations of various Western and non-Western harmonisation styles, and whether cultural familiarity with a harmonic idiom such as major and minor mode would consistently relate to emotion communication. The results indicate that Western concepts of harmony are not relevant for participants unexposed to Western music when other emotional cues (tempo, pitch height, articulation, timbre) are kept relatively constant. At the same time, harmonic style alone has the ability to colour the emotional expression in music if it taps the appropriate cultural connotations. The preference for one harmonisation style over another, including the major-happy/minor-sad distinction, is influenced by culture. Finally, our findings suggest that although differences emerge across different harmonisation styles, acoustic roughness influences the expression of emotion in similar ways across cultures; preference for consonance however seems to be dependent on cultural familiarity