Passive investing before and after the crisis: investors' views on exchange-traded funds and competing index products

Investment in exchange-traded funds (ETFs) has been remarkably robust in the course of the recent financial crisis. This paper analyzes investors' perceptions of ETFs and other indexing products by comparing the answers to two surveys of ETF users carried out in 2008 and 2009, before and after the height of the financial crisis. We find that the crisis has divided the ETF market in two segments. Whereas ETFs in standard asset classes have been unaffected by the crisis, ETFs for alternative asset classes face challenges. However, ETFs are generally well ranked in comparison to other indexing products – presumably because of an increased focus on liquidity and transparency

Do you listen to music while studying? A portrait of how people use music to optimize their cognitive performance

Contains fulltext : 239174.pdf (Publisher’s version ) (Open Access)The effect of background music (BGM) on cognitive task performance is a popular topic. However, the evidence is not converging: experimental studies show mixed results depending on the task, the type of music used and individual characteristics. Here, we explored how people use BGM while optimally performing various cognitive tasks in everyday life, such as reading, writing, memorizing, and critical thinking. Specifically, the frequency of BGM usage, preferred music types, beliefs about the scientific evidence on BGM, and individual characteristics, such as age, extraversion and musical background were investigated. Although the results confirmed highly diverse strategies among individuals regarding when, how often, why and what type of BGM is used, we found several general tendencies: people tend to use less BGM when engaged in more difficult tasks, they become less critical about the type of BGM when engaged in easier tasks, and there is a negative correlation between the frequency of BGM and age, indicating that younger generations tend to use more BGM than older adults. The current and previous evidence are discussed in light of existing theories. Altogether, this study identifies essential variables to consider in future research and further forwards a theory-driven perspective in the field.11 p

Towards a Notion of Distributed Time for Petri Nets

We set the ground for research on a timed extension of Petri nets where time parameters are associated with tokens and arcs carry constraints that qualify the age of tokens required for enabling. The novelty is that, rather than a single global clock, we use a set of unrelated clocks --- possibly one per place --- allowing a local timing as well as distributed time synchronisation. We give a formal definition of the model and investigate properties of local versus global timing, including decidability issues and notions of processes of the respective models

Human parietal reach region primarily encodes intrinsic visual direction, not extrinsic movement direction, in a visual motor dissociation task.

Posterior parietal cortex (PPC) participates in the planning of visuospatial behaviors, including reach movements, in gaze-centered coordinates. It is not known if these representations encode the visual goal in retinal coordinates, or the movement direction relative to gaze. Here, by dissociating the intrinsic retinal stimulus from the extrinsic direction of movement, we show that PPC employs a visual code. Using delayed pointing and event-related functional magnetic resonance imaging, we identified a cluster of PPC regions whose activity was topographically (contralaterally) related to the direction of the planned movement. We then switched the normal visual-motor spatial relationship by adapting subjects to optical left/right reversing prisms. With prisms, movement-related PPC topography reversed, remaining tied to the retinal image. Thus, remarkably, the PPC region in each hemisphere now responded more for planned ipsilateral pointing movements. Other non-PPC regions showed the opposite world- or motor-fixed pattern. These findings suggest that PPC primarily encodes not motor commands but movement goals in visual coordinates

Full-field Chromatic Pupillometry for the Assessment of the Postillumination Pupil Response Driven by Melanopsin-Containing Retinal Ganglion Cells

Citation: Lei S, Goltz HC, Chandrakumar M, Wong AMF. Full-field chromatic pupillometry for the assessment of the postillumination pupil response driven by melanopsin-containing retinal ganglion cells. Invest Ophthalmol Vis Sci. 2014;55:4496-4503

A Logic with Reverse Modalities for History-preserving Bisimulations

We introduce event identifier logic (EIL) which extends Hennessy-Milner logic by the addition of (1) reverse as well as forward modalities, and (2) identifiers to keep track of events. We show that this logic corresponds to hereditary history-preserving (HH) bisimulation equivalence within a particular true-concurrency model, namely stable configuration structures. We furthermore show how natural sublogics of EIL correspond to coarser equivalences. In particular we provide logical characterisations of weak history-preserving (WH) and history-preserving (H) bisimulation. Logics corresponding to HH and H bisimulation have been given previously, but not to WH bisimulation (when autoconcurrency is allowed), as far as we are aware. We also present characteristic formulas which characterise individual structures with respect to history-preserving equivalences.Comment: In Proceedings EXPRESS 2011, arXiv:1108.407

Brief Communication Gaze-Centered Updating of Visual Space in Human Parietal Cortex

Single-unit recordings have identified a region in the posterior parietal cortex (PPC) of the monkey that represents and updates visual space in a gaze-centered frame. Here, using event-related functional magnetic resonance imaging, we identified an analogous bilateral region in the human PPC that shows contralateral topography for memory-guided eye movements and arm movements. Furthermore, when eye movements reversed the remembered horizontal target location relative to the gaze fixation point, this PPC region exchanged activity across the two cortical lobules. This shows that the human PPC dynamically updates the spatial goals for action in a gaze-centered frame

Short-Term Saccadic Adaptation in Patients With Anisometropic Amblyopia

PURPOSE. Amblyopia is a developmental disorder characterized by impairment of spatiotemporal visual processing that also affects oculomotor and manual motor function. We investigated the effects of amblyopia on short-term visuomotor adaptation using a saccadic adaptation paradigm. METHODS. A total of 8 patients with anisometropic amblyopia and 11 visually-normal controls participated. Saccadic adaptation was induced using a double-step paradigm that displaced a saccadic visual target (at 6198) back toward central fixation by 4.28 during the ongoing saccade. Three test blocks, preadaptation, adaptation, and postadaptation, were performed sequentially while participants viewed binocularly and monocularly with the amblyopic and fellow eyes (nondominant and dominant eyes in controls) in three separate sessions. The spatial and temporal characteristics of saccadic adaptation were measured. RESULTS. Patients exhibited diminished saccadic gain adaptation. The percentage change in saccadic gain was lower in patients during amblyopic eye and binocular viewing compared to controls. Saccadic latencies were longer, and saccadic gains and latencies were more variable in patients during amblyopic eye viewing. The time constants of adaptation were comparable between controls and patients under all viewing conditions. CONCLUSIONS. The short-term adaptation of saccadic gain was weaker and more variable in patients during amblyopic eye and binocular viewing. Our findings suggest that visual error information necessary for adaptation is imprecise in amblyopia, leading to reduced modulation of saccadic gain, and support the proposal that the error signal driving saccadic adaptation is visual