168,205 research outputs found

    Privatization Matters: Bank Efficiency in Transition Countries

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    To investigate the impact of bank privatization in transition countries, we take the largest banks in six relatively advanced countries, namely, Bulgaria, the Czech Republic, Croatia, Hungary, Poland and Romania. Income and balance sheet characteristics are compared across four bank ownership types. Efficiency measures are computed from stochastic frontiers and used in ownership and privatization regressions having dummy variables for bank type. Our empirical results support the hypotheses that foreign-owned banks are most efficient and governmentowned banks are least efficient. In addition, the importance of attracting a strategic foreign owner in the privatization process is confirmed. However, counter to the conjecture that foreign banks cream skim, we find that domestic banks have a local advantage in pursuing fee-forservice business. Finally, we show that both the method and the timing of privatization matter to efficiency; specifically, voucher privatization does not lead to increased efficiency and earlyprivatized banks are more efficient than later-privatized banks even though we find no evidence of a selection effect.http://deepblue.lib.umich.edu/bitstream/2027.42/40065/3/wp679.pd

    Neuroelectromagnetic signatures of the reproduction of supra-second durations

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    AbstractWhen participants are asked to reproduce an earlier presented duration, EEG recordings typically show a slow potential that develops over the fronto-central regions of the brain and is assumed to be generated in the supplementary motor area (SMA). This contingent negative variation (CNV) has been linked to anticipation, preparation and formation of temporal judgment (Macar, Vidal, and Casini, 1999, Experimental Brain Research, 125(3), 271–80). Although the interpretation of the CNV amplitude is problematic (Kononowicz and Van Rijn, (2011), Frontiers in Integrative Neuroscience, 5(48); Ng, Tobin, and Penney, 2011, Frontiers in Integrative Neuroscience, 5(77)), the observation of this slow potential is extremely robust, and thus one could assume that magnetic recordings of brain activity should show similar activity patterns. However, interval timing studies using durations shorter than one second did not provide unequivocal evidence as to whether CNV has a magnetic counterpart (CMV). As interval timing has been typically associated with durations longer than one second, participants in this study were presented intervals of 2, 3 or 4s that had to be reproduced in setup similar to the seminal work of Elbert et al. (1991, Psychophysiology, 28(6), 648–55) while co-recording EEG and MEG.The EEG data showed a clear CNV during the standard and the reproduction interval. In the reproduction interval the CNV steadily builds up from the onset of interval for both stimulus and response locked data. The MEG data did not show a CNV-resembling ramping of activity, but only showed a pre-movement magnetic field (preMMF) that originated from the SMA, occurring approximately 0.6s before the termination of the timed interval. These findings support the notion that signatures of timing are more straightforwardly measured using EEG, and show that the measured MEG signal from the SMA is constrained to the end of reproduction interval, before the voluntary movement.Moreover, we investigated a link between timing behavior and the early iCNV and late CNV amplitudes to evaluate the hypothesis that these amplitudes reflect the accumulation of temporal pulses. Larger iCNV amplitudes predicted shorter reproduced durations. This effect was more pronounced for the 2s interval reproduction, suggesting that preparatory strategies depend on the length of reproduced interval. Similarly to Elbert et al. (1991, Psychophysiology, 28(6), 648–55), longer reproductions were associated with smaller CNV amplitudes, both between conditions and across participants within the same condition. As the temporal accumulation hypothesis predicts the inverse, these results support the proposal by Van Rijn et al. (2011, Frontiers in Integrative Neuroscience, 5) that the CNV reflects other temporally driven processes such as temporal expectation and preparation rather than temporal accumulation itself

    Retinal oscillations carry visual information to cortex

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    Thalamic relay cells fire action potentials that transmit information from retina to cortex. The amount of information that spike trains encode is usually estimated from the precision of spike timing with respect to the stimulus. Sensory input, however, is only one factor that influences neural activity. For example, intrinsic dynamics, such as oscillations of networks of neurons, also modulate firing pattern. Here, we asked if retinal oscillations might help to convey information to neurons downstream. Specifically, we made whole-cell recordings from relay cells to reveal retinal inputs (EPSPs) and thalamic outputs (spikes) and analyzed these events with information theory. Our results show that thalamic spike trains operate as two multiplexed channels. One channel, which occupies a low frequency band (<30 Hz), is encoded by average firing rate with respect to the stimulus and carries information about local changes in the image over time. The other operates in the gamma frequency band (40-80 Hz) and is encoded by spike time relative to the retinal oscillations. Because these oscillations involve extensive areas of the retina, it is likely that the second channel transmits information about global features of the visual scene. At times, the second channel conveyed even more information than the first.Comment: 21 pages, 10 figures, submitted to Frontiers in Systems Neuroscienc

    Privatization matters: Bank efficiency in transition countries

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    To investigate the impact of bank privatization in transition countries, we take the largest banks in six relatively advanced countries, namely, Bulgaria, the Czech Republic, Croatia, Hungary, Poland and Romania. Income and balance sheet characteristics are compared across four bank ownership types. Efficiency measures are computed from stochastic frontiers and used in ownership and privatization regressions having dummy variables for bank type. Our empirical results support the hypotheses that foreign-owned banks are most efficient and government-owned banks are least efficient. In addition, the importance of attracting a strategic foreign owner in the privatization process is confirmed. However, counter to the conjecture that foreign banks cream skim, we find that domestic banks have a local advantage in pursuing fee-for-service business. Finally, we show that both the method and the timing of privatization matter to efficiency; specifically, voucher privatization does not lead to increased efficiency and early-privatized banks are more efficient than later-privatized banks even though we find no evidence of a selection effect.

    Converting Static Image Datasets to Spiking Neuromorphic Datasets Using Saccades

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    Creating datasets for Neuromorphic Vision is a challenging task. A lack of available recordings from Neuromorphic Vision sensors means that data must typically be recorded specifically for dataset creation rather than collecting and labelling existing data. The task is further complicated by a desire to simultaneously provide traditional frame-based recordings to allow for direct comparison with traditional Computer Vision algorithms. Here we propose a method for converting existing Computer Vision static image datasets into Neuromorphic Vision datasets using an actuated pan-tilt camera platform. Moving the sensor rather than the scene or image is a more biologically realistic approach to sensing and eliminates timing artifacts introduced by monitor updates when simulating motion on a computer monitor. We present conversion of two popular image datasets (MNIST and Caltech101) which have played important roles in the development of Computer Vision, and we provide performance metrics on these datasets using spike-based recognition algorithms. This work contributes datasets for future use in the field, as well as results from spike-based algorithms against which future works can compare. Furthermore, by converting datasets already popular in Computer Vision, we enable more direct comparison with frame-based approaches.Comment: 10 pages, 6 figures in Frontiers in Neuromorphic Engineering, special topic on Benchmarks and Challenges for Neuromorphic Engineering, 2015 (under review

    Privatization Matters: Bank Efficiency in Transition Countries

    Get PDF
    To investigate the impact of bank privatization in transition countries, we take the largest banks in six relatively advanced countries, namely, Bulgaria, the Czech Republic, Croatia, Hungary, Poland and Romania. Income and balance sheet characteristics are compared across four bank ownership types. Efficiency measures are computed from stochastic frontiers and used in ownership and privatization regressions having dummy variables for bank type. Our empirical results support the hypotheses that foreign-owned banks are most efficient and governmentowned banks are least efficient. In addition, the importance of attracting a strategic foreign owner in the privatization process is confirmed. However, counter to the conjecture that foreign banks cream skim, we find that domestic banks have a local advantage in pursuing fee-forservice business. Finally, we show that both the method and the timing of privatization matter to efficiency; specifically, voucher privatization does not lead to increased efficiency and earlyprivatized banks are more efficient than later-privatized banks even though we find no evidence of a selection effect.bank efficiency, bank privatization, strategic foreign owner, transition countries

    Dissociating Explicit and Implicit Timing in Parkinson\u2019s Disease Patients: Evidence from Bisection and Foreperiod Tasks

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    A consistent body of literature reported that Parkinson\u2019s disease (PD) is marked by severe deficits in temporal processing. However, the exact nature of timing problems in PD patients is still elusive. In particular, what remains unclear is whether the temporal dysfunction observed in PD patients regards explicit and/or implicit timing. Explicit timing tasks require participants to attend to the duration of the stimulus, whereas in implicit timing tasks no explicit instruction to process time is received but time still affects performance. In the present study, we investigated temporal ability in PD by comparing 20 PD participants and 20 control participants in both explicit and implicit timing tasks. Specifically, we used a time bisection task to investigate explicit timing and a foreperiod task for implicit timing. Moreover, this is the first study investigating sequential effects in PD participants. Results showed preserved temporal ability in PD participants in the implicit timing task only (i.e., normal foreperiod and sequential effects). By contrast, PD participants failed in the explicit timing task as they displayed shorter perceived durations and higher variability compared to controls. Overall, the dissociation reported here supports the idea that timing can be differentiated according to whether it is explicitly or implicitly processed, and that PD participants are selectively impaired in the explicit processing of time

    The impact of cognitive load on operatic singers' timing performance

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    In the present paper, we report the results of an empirical study on the effects of cognitive load on operatic singing. The main aim of the study was to investigate to what extent a working memory task affected the timing of operatic singers' performance. Thereby, we focused on singers' tendency to speed up, or slow down their performance of musical phrases and pauses. Twelve professional operatic singers were asked to perform an operatic aria three times; once without an additional working memory task, once with a concurrent working memory task (counting shapes on a computer screen), and once with a relatively more difficult working memory task (more shapes to be counted appearing one after another). The results show that, in general, singers speeded up their performance under heightened cognitive load. Interestingly, this effect was more pronounced in pauses-more in particular longer pauses-compared to musical phrases. We discuss the role of sensorimotor control and feedback processes in musical timing to explain these findings
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