Bank Competition, Asset Allocations and Risk of Failure: An Empirical Investigation

This study is an empirical investigation of theoretical predictions concerning the impact of bank competition on bank risk and asset allocations. Recent work (Boyd, De Nicolò and Jalal, 2009, BDNJ henceforth) predicts that as competition in banking increases, the loan-to-asset ratio will rise (under reasonable assumptions), but the probability of bank failure can either increase or decrease. However, the probability of bank failure will fall if and only if borrowers’ response to take on less risk as loan rates decline is sufficiently strong. We test these predictions using two samples with radically different attributes. With both, we find that banks’ probability of failure is negatively and significantly related to measures of competition. We also find that as competition intensifies, borrower risk decreases and the loan-to-asset ratio increases. These results are consistent with the predictions of the BDNJ model.

Resonant plasmonic nanoparticles for multicolor second harmonic imaging

Nanoparticles capable of efficiently generating nonlinear optical signals, like second harmonic generation, are attracting a lot of attention as potential background-free and stable nano-probes for biological imaging. However, second harmonic nanoparticles of different species do not produce readily distinguishable optical signals, as the excitation laser mainly defines their second harmonic spectrum. This is in marked contrast to other fluorescent nano-probes like quantum dots that emit light at different colors depending on their sizes and materials. Here, we present the use of resonant plasmonic nanoparticles, combined with broadband phase-controlled laser pulses, as tunable sources of multicolor second harmonic generation. The resonant plasmonic nanoparticles strongly interact with the electromagnetic field of the incident light, enhancing the efficiency of nonlinear optical processes. Because the plasmon resonance in these structures is spectrally narrower than the laser bandwidth, the plasmonic nanoparticles imprint their fingerprints on the second harmonic spectrum. We show how nanoparticles of different sizes produce different colors in the second harmonic spectra even when excited with the same laser pulse. Using these resonant plasmonic nanoparticles as nano-probes is promising for multicolor second harmonic imaging while keeping all the advantages of nonlinear optical microscopy.Peer ReviewedPostprint (published version

Anomalous resilient to decoherence macroscopic quantum superpositions generated by universally covariant optimal quantum cloning

We show that the quantum states generated by universal optimal quantum cloning of a single photon represent an universal set of quantum superpositions resilient to decoherence. We adopt Bures distance as a tool to investigate the persistence ofquantum coherence of these quantum states. According to this analysis, the process of universal cloning realizes a class of quantum superpositions that exhibits a covariance property in lossy configuration over the complete set of polarization states in the Bloch sphere.Comment: 8 pages, 6 figure

Anomalous lack of decoherence of the Macroscopic Quantum Superpositions based on phase-covariant Quantum Cloning

We show that all Macroscopic Quantum Superpositions (MQS) based on phase-covariant quantum cloning are characterized by an anomalous high resilence to the de-coherence processes. The analysis supports the results of recent MQS experiments and leads to conceive a useful conjecture regarding the realization of complex decoherence - free structures for quantum information, such as the quantum computer.Comment: 4 pages, 3 figure

Nanoscale magnetophotonics

This Perspective surveys the state-of-the-art and future prospects of science and technology employing the nanoconfined light (nanophotonics and nanoplasmonics) in combination with magnetism. We denote this field broadly as nanoscale magnetophotonics. We include a general introduction to the field and describe the emerging magneto-optical effects in magnetoplasmonic and magnetophotonic nanostructures supporting localized and propagating plasmons. Special attention is given to magnetoplasmonic crystals with transverse magnetization and the associated nanophotonic non-reciprocal effects, and to magneto-optical effects in periodic arrays of nanostructures. We give also an overview of the applications of these systems in biological and chemical sensing, as well as in light polarization and phase control. We further review the area of nonlinear magnetophotonics, the semiconductor spin-plasmonics, and the general principles and applications of opto-magnetism and nano-optical ultrafast control of magnetism and spintronics

It’s not over yet: the impact of worry on emotional recovery

Emotional reactivity and recovery are crucial for maintaining well-being. It remains unknown, however, to what extent emotion modulates the time course of recovery assessed using a simple categorization task and how this varies based on individual differences in worry. To address these questions, 35 participants viewed emotional pictures, followed by abstract greeble targets, which were to be categorized. Greebles were presented between 100 ms and 4,000 ms after picture offset. Physiological measures including skin conductance level and the corrugator supercilii were recorded and served as indicators of responsivity to emotional pictures. Measures of reaction time (RT) and accuracy scores were taken as indicators of the impact of emotion on facilitation or interference to the greeble target. Effects of interference and facilitation were observed up to 4,000 ms after emotional pictures on RT and accuracy scores. High worry was associated with greater (1) corrugator supercilii and skin conductance level to negative versus positive and neutral pictures and (2) interference from emotional pictures on accuracy scores. Overall, these findings suggest that subsequent processing is still impacted up to 4,000 ms after the offset of emotional pictures, particularly for negative events in individuals with high worry

Local and Global Analytic Solutions for a Class of Characteristic Problems of the Einstein Vacuum Equations in the "Double Null Foliation Gauge"

The main goal of this work consists in showing that the analytic solutions for a class of characteristic problems for the Einstein vacuum equations have an existence region larger than the one provided by the Cauchy-Kowalevski theorem due to the intrinsic hyperbolicity of the Einstein equations. To prove this result we first describe a geometric way of writing the vacuum Einstein equations for the characteristic problems we are considering, in a gauge characterized by the introduction of a double null cone foliation of the spacetime. Then we prove that the existence region for the analytic solutions can be extended to a larger region which depends only on the validity of the apriori estimates for the Weyl equations, associated to the "Bel-Robinson norms". In particular if the initial data are sufficiently small we show that the analytic solution is global. Before showing how to extend the existence region we describe the same result in the case of the Burger equation, which, even if much simpler, nevertheless requires analogous logical steps required for the general proof. Due to length of this work, in this paper we mainly concentrate on the definition of the gauge we use and on writing in a "geometric" way the Einstein equations, then we show how the Cauchy-Kowalevski theorem is adapted to the characteristic problem for the Einstein equations and we describe how the existence region can be extended in the case of the Burger equation. Finally we describe the structure of the extension proof in the case of the Einstein equations. The technical parts of this last result is the content of a second paper.Comment: 68 page

Ice-bridging frustration by self-ejection of single droplets results in superior anti-frosting surfaces

Surfaces capable of delaying the frosting passively and facilitating its removal are highly desirable in fields where ice introduces inefficiencies and risks. Coalescence jumping, enabled by highly hydrophobic surfaces, is already exploited to slow down the frosting but it is insufficient to completely eliminate the propagation by ice-bridging. We show how the self-ejection of single condensation droplets can frustrate the ice bridges of all the condensation droplets leading to a frost velocity lower than 0.5 um/s thus dropping below the current limits of passive surfaces by a factor of at least 2. Arrays of truncated microcones, covered by uniformly hydrophobic nanostructures, enable individual condensation droplets to growth and self-propel towards the top of the microstructures and to self-eject once a precise volume is reached. The independency of self-ejection on the neighbour droplets allows a precise control on the droplets' size and distance distributions and the ice-bridging frustration. The most performant microstructures tend to cones with a sharp tip on which the percentage of self-ejection is maximum. Looking towards applications, tapered microstructures allow maximising the percentage of self-ejecting drops while maintaining a certain mechanical strength. Further, it is shown that inserted pinning sites are not essential, which greatly facilitates manufacturing