Collective rearrangement at the onset of flow of a polycrystalline hexagonal columnar phase

Creep experiments on polycrystalline surfactant hexagonal columnar phases show a power law regime, followed by a drastic fluidization before reaching a final stationary flow. The scaling of the fluidization time with the shear modulus of the sample and stress applied suggests that the onset of flow involves a bulk reorganization of the material. This is confirmed by X-ray scattering under stress coupled to \textit{in situ} rheology experiments, which show a collective reorientation of all crystallites at the onset of flow. The analogy with the fracture of heterogeneous materials is discussed.Comment: to appear in Phys. Rev. Let

How Costly is Financial (not Economic) Distress? Evidence from Highly Leveraged Transactions that Became Distressed

This paper studies thirty-one highly leveraged transactions (HLTs) of the 1980s that subsequently became financially distressed. At the time of distress, all sample firms have operating margins that are positive and in the majority of cases greater than the median for the industry. Therefore, we consider these firms financially distressed, not economically distressed. The net effect of the HLT and financial distress is a slight increase in value -- from pre-transaction to distress resolution, the sample firms experience a marginally positive change in (market- or industry-adjusted) value. This finding strongly suggests that, overall, the HLTs of the late 1980s succeeded in creating value. We also present quantitative and qualitative estimates of the (direct and indirect)costs of financial distress and their determinants. Our preferred estimates of the costs of financial distress are 10% of firm value. Our most conservative estimates do not exceed 23% of firm value. Operating margins of the distressed firms increase immediately after the HLT, decline when the firms become distressed and while they are distressed, but then rebound after the distress is resolved. Consistent with some costs of financial distress, we find evidence of unexpected cuts in capital expenditures, undesired asset sales, and costly managerial delay in restructuring. To the extent they occur, the costs of financial distress that we identify are heavily concentrated in the period after the firms become distressed, but before they enter Chapter 11.

Visuospatial tasks suppress craving for cigarettes.

The Elaborated Intrusion (EI) theory of desire posits that visual imagery plays a key role in craving. We report a series of experiments testing this hypothesis in a drug addiction context. Experiment 1 showed that a mental visual imagery task with neutral content reduced cigarette craving in abstaining smokers, but that an equivalent auditory task did not. The effect of visual imagery was replicated in Experiment 2, which also showed comparable effects of non-imagery visual working memory interference. Experiment 3 showed that the benefit of visual over auditory interference was not dependent upon imagery being used to induce craving. Experiment 4 compared a visuomotor task, making shapes from modeling clay, with a verbal task (counting back from 100), and again showed a benefit of the visual over the non-visual task. We conclude that visual imagery supports craving for cigarettes. Competing imagery or visual working memory tasks may help tackle craving in smokers trying to quit

Application of compressed sensing to the simulation of atomic systems

Compressed sensing is a method that allows a significant reduction in the number of samples required for accurate measurements in many applications in experimental sciences and engineering. In this work, we show that compressed sensing can also be used to speed up numerical simulations. We apply compressed sensing to extract information from the real-time simulation of atomic and molecular systems, including electronic and nuclear dynamics. We find that for the calculation of vibrational and optical spectra the total propagation time, and hence the computational cost, can be reduced by approximately a factor of five.Comment: 7 pages, 5 figure

Implicit cognition is impaired and dissociable in a head-injured group with executive deficits

Implicit or non-conscious cognition is traditionally assumed to be robust to pathology but Gomez-Beldarrain et al (1999, 2002) recently showed deficits on a single implicit task after head injury. Laboratory research suggests that implicit processes dissociate. This study therefore examined implicit cognition in 20 head-injured patients and age- and I.Q.-matched controls using a battery of four implicit cognition tasks: a Serial Reaction Time task (SRT), mere exposure effect task, automatic stereotype activation and hidden co-variation detection. Patients were assessed on an extensive neuropsychological battery, and MRI scanned. Inclusion criteria included impairment on at least one measure of executive function. The patient group was impaired relative to the control group on all the implicit cognition tasks except automatic stereotype activation. Effect size analyses using the control mean and standard deviation for reference showed further dissociations across patients and across implicit tasks. Patients impaired on implicit tasks had more cognitive deficits overall than those unimpaired, and a larger Dysexecutive Self/Other discrepancy (DEX) score suggesting greater behavioural problems. Performance on the SRT task correlated with a composite measure of executive function. Head-injury thus produced heterogeneous impairments in the implicit acquisition of new information. Implicit activation of existing knowledge structures appeared intact. Impairments in implicit cognition and executive function may interact to produce dysfunctional behaviour after head-injury. Future comparisons of implicit and explicit cognition should use several measures of each function, to ensure that they measure the latent variable of interest

Electronic Griffiths phase of the d=2 Mott transition

We investigate the effects of disorder within the T=0 Brinkman-Rice (BR) scenario for the Mott metal-insulator transition (MIT) in two dimensions (2d). For sufficiently weak disorder the transition retains the Mott character, as signaled by the vanishing of the local quasiparticles (QP) weights Z_{i} and strong disorder screening at criticality. In contrast to the behavior in high dimensions, here the local spatial fluctuations of QP parameters are strongly enhanced in the critical regime, with a distribution function P(Z) ~ Z^{\alpha-1} and \alpha tends to zero at the transition. This behavior indicates a robust emergence of an electronic Griffiths phase preceding the MIT, in a fashion surprisingly reminiscent of the "Infinite Randomness Fixed Point" scenario for disordered quantum magnets.Comment: 4+ pages, 5 figures, final version to appear in Physical Review Letter

"Electronic Identity for Europe": Moving From Problems to Solutions

Electronic Identity (eID) is the backbone of modern communications and transactions in the digital world, as well as a key driver for the growth of the EU economy and the completion of the Digital Single Market. The latter, in effect, can only be accomplished when citizens from one Member State (MS) can easily and unobtrusively access services and use applications, including signing electronically, from any other Member State. Despite the implementation of different identity management systems (IMS), the numerous political declarations and initiatives in this area, the development of various research projects and eID technologies, the discussion on the necessary legal means through which to create an interoperable pan-European eID has not yet taken place. In addition, the processing and management of electronic identities is regulated – at the EU level - through principles, rules and concepts "borrowed" from different EU legal instruments (Data protection, eSignatures and Services Directives being the most relevant ones). As such, one of the main challenges posed to European electronic Identity is of a legal nature. In this context, the Institute for Prospective Technological Studies (IPTS), within the framework of the 2011 LSPI Conference organized a workshop – entitled "Electronic Identity for Europe" – devoted to the legal framework that is necessary to set in place in order to accompany and enforce the already existing technological answers.Â