Yin-Yang representation of financial crisis: a Korean perspective

Although the concepts of Western-Eastern integration to optimise management strategies are well-established, investigations on the applicability of these concepts in real-life situations are lacking. This study investigates how integration of (Eastern) Yin-Yang principles of seeking balance into Western concepts benefitted Koreans in combatting financial crises repercussions. Through analysis of 519 South Korean economic magazine covers taken over the period 2007-2012, the study shows the mindset of Korean society during the 2008 financial crisis. The covers provide a balanced interpretation of crisis events as both disastrous and opportunistic. Traditional Yin-Yang values therefore appear to be preserved in Korean management philosophy, even though contemporary Korean business strategies are strongly influenced by Western principles. By comparing these findings with social attitudes during previous crises in Korea, the study provides a real-life example of possible benefits of integrating Eastern and Western philosophy in management strategies

Hearing aids do not alter cortical entrainment to speech at audible levels in mild-to-moderately hearing-impaired subjects

Background: Cortical entrainment to speech correlates with speech intelligibility and attention to a speech stream in noisy environments. However, there is a lack of data on whether cortical entrainment can help in evaluating hearing aid fittings for subjects with mild to moderate hearing loss. One particular problem that may arise is that hearing aids may alter the speech stimulus during (pre-)processing steps, which might alter cortical entrainment to the speech. Here, the effect of hearing aid processing on cortical entrainment to running speech in hearing impaired subjects was investigated. Methodology: Seventeen native English-speaking subjects with mild-to-moderate hearing loss participated in the study. Hearing function and hearing aid fitting were evaluated using standard clinical procedures. Participants then listened to a 25-minute audiobook under aided and unaided conditions at 70 dB A sound pressure level (SPL) in quiet conditions. EEG data were collected using a 32-channel system. Cortical entrainment to speech was evaluated using decoders reconstructing the speech envelope from the EEG data. Null decoders, obtained from EEG and the time-reversed speech envelope, were used to assess the chance level reconstructions. Entrainment in the delta- (1-4 Hz) and theta- (4-8 Hz) band, as well as wideband (1-20 Hz) EEG data was investigated. Results: Significant cortical responses could be detected for all but one subject in all three frequency bands under both aided and unaided conditions. However, no significant differences could be found between the two conditions in the number of responses detected, nor in the strength of cortical entrainment. The results show that the relatively small change in speech input provided by the hearing aid was not sufficient to elicit a detectable change in cortical entrainment. Conclusion: For subjects with mild to moderate hearing loss, cortical entrainment to speech in quiet at an audible level is not affected by hearing aids. These results clear the pathway for exploring the potential to use cortical entrainment to running speech for evaluating hearing aid fitting at lower speech intensities (which could be inaudible when unaided), or using speech in noise conditions

Fetal Movement Counting Using Optical Fibre Sensors

Daily fetal movement counting based on maternal perception is widely deployed to monitor fetal wellbeing. However, the counting performed by the mother is prone to errors for various reasons. There are limited devices on the market that can provide reliable and automatic counting. This paper presents a prototype of a novel fetal movement monitoring device based on fibre Bragg grating sensors. Deformation of the skin caused by a fetal movement can lead to a change of the strain and stress on the optical fibre sensors, therefore can induce distortions to the breathing pattern of the mother. In the study data was gathered by the sensors through strain measurement and was post-processed using independent component analysis (ICA) and high-pass filtering to show the instances of the fetal movements. Information gathered during user trials with the prototype suggests that the system detects significantly higher numbers of fetus movements than that observed based on the mother’s perception. Among the various techniques available for fetal movement monitoring, fibre optic sensing provides many advantages including multiplex capability, flexibility and minimal size, making the concept an attractive solution for reliable monitoring of antenatal fetal movements

Persistent atrial fibrillation hierarchical activation: from highest DF sites to wave fractionation at the boundaries

Preclinical studies showed a relationship between high dominant frequency areas (HDFA) and wave fractionation, but evidence in patient who atrial fibrillation (AF) persists for long-term periods (persAF) it is not well defined. This study aims to assess the spatiotemporal organization characteristics at HDFAs is persAF and its impact after per standard pulmonary vein isolation (PVI). Eight persAF patients had a non-contact array catheter deployed into the left atrium to collect up to 2048 AF electrograms (AEG) for 15 s. AEGs were band-pass filtered (3-30 Hz) followed by ventricular farfield cancellation. DF between 4-10 Hz and its respective organization index (OI) were calculated (4 s with 50% overlap) to produce 3D DF and OI maps. HDFA defined as the regions within a 0.25 Hz drop from the highest DF were determined and their centre of gravity (CG) calculated. Highest DF sites showed a higher OI at their core when compared to the periphery (0.422±0.101 vs. 0.386±0.126, p=0.02) and increased again organization at sites distant from the HDFAs. Similarly, after PVI, OI remained higher as compared to their periphery (0.372±0.026 vs. 0.332±0.036, p=0.22), but with significant lower values when compared with baseline (p<0.0001). PersAF patients showed higher organization in the HDFAs core when compared with its periphery

Are atrial fibrillation highest dominant frequency (HDF) areas the source of dominant excitation patterns? A left atrial panoramic view

Atrial fibrillation (AF) catheter ablation success depends on the possibility to accurately determine areas on the atrial endocardium at which AF activation originates. One way to determine if major AF activation pathways originate at identified source is through causality analysis. This work assessed to what extent left atrial highest dominant frequency (HDF) areas can be identified as sources of activation pathways in 10 male subjects suffering from persistent AF. Virtual electrograms were collected from 64 endocardial locations for at least 5 minutes. Frequency and causality were analyzed on 4 s signal segments Causality was assessed using the directed transfer function (DTF) algorithm, and AF activation sources were identified as endocardial locations of which the VEGM signal had high influence on other VEGM signals. Co-localization of high influence and HDF areas was evaluated for different area overlap and spectral organisation (OI) thresholds. Results show that, on average, good overlap only existed in 64.6% (± 8.8%) over all subject using the lowest threshold settings. Good overlap rates reduced with more conservative thresholds. This indicates that HDF areas might not always identify origins of main AF activation pathways

Automatic extraction of recurrent patterns of high dominant frequency mapping during human persistent atrial fibrillation

Purpose: Identifying targets for catheter ablation remains challenging in persistent atrial fibrillation (persAF). The dominant frequency (DF) of atrial electrograms during atrial fibrillation (AF) is believed to primarily reflect local activation. Highest DF (HDF) might be responsible for the initiation and perpetuation of persAF. However, the spatiotemporal behaviour of DF remains not fully understood. Some DFs during persAF were shown to lack spatiotemporal stability, while others exhibit recurrent behaviour. We sought to develop a tool to automatically detect recurrent DF patterns in persAF patients. Methods: Non-contact mapping of the left atrium (LA) was performed in 10 patients undergoing persAF HDF ablation. 2048 virtual electrograms (vEGMs, EnSite Array, Abbott Laboratories, USA) were collected for up to 5 min before and after ablation. Frequency spectrum was estimated using fast Fourier transform and DF was identified as the peak between 4-10 Hz and organization index (OI) was calculated. The HDF maps were identified per 4-second window and an automated pattern recognition algorithm was used to find recurring HDF spatial patterns. Dominant patterns (DPs) were defined as the HDF pattern with the highest recurrence. Results: DPs were found in all patients. Patients in atrial flutter after ablation had a single DP over the recorded time period. The time interval (median [IQR]) of DP recurrence for the patients in AF after ablation (7 patients) decreased from 21.1 s [11.8 49.7s] to 15.7 s [6.5 18.2 s]. The DF inside the DPs presented lower temporal standard deviation (0.18±0.06 Hz vs. 0.29±0.12 Hz, p<0.05) and higher OI (0.35±0.03 vs. 0.31±0.04, p<0.05). The atrial regions with the highest proportion of HDF region were the septum and the left upper pulmonary vein. Conclusion: Multiple recurrent spatiotemporal HDF patterns exist during persAF. The proposed method can identify and quantify the spatiotemporal repetition of the HDFs, where the high recurrences of DP may suggest a more organised rhythm. DPs presented a more consistent DF and higher organisation compared with non-DPs, suggesting that DF with higher OI might be more likely to recur. Recurring patterns offer a more comprehensive dynamic insight of persAF behaviour, and ablation targeting such regions may be beneficial

Origin of defect-related green emission from ZnO nanoparticles: effect of surface modification

We investigated the optical properties of colloidal-synthesized ZnO spherical nanoparticles prepared from 1-octadecene (OD), a mixture of trioctylamine (TOA) and OD (1:10), and a mixture of trioctylphosphine oxide (TOPO) and OD (1:12). It is found that the green photoluminescence (PL) of samples from the mixture of TOA/OD and TOPO/OD is largely suppressed compared with that from pure OD. Moreover, it is found that all spherical nanoparticles have positive zeta potential, and spherical nanoparticles from TOA/OD and TOPO/OD have a smaller zeta potential than those from OD. A plausible explanation is that oxygen vacancies, presumably located near the surface, contribute to the green PL, and the introduction of TOA and TOPO will reduce the density of oxygen vacancies near the surfaces. Assuming that the green emission arises due to radiative recombination between deep levels formed by oxygen vacancies and free holes, we estimate the size of optically active spherical nanoparticles from the spectral energy of the green luminescence. The results are in good agreement with results from TEM. Since this method is independent of the degree of confinement, it has a great advantage in providing a simple and practical way to estimate the size of spherical nanoparticles of any size. We would like to point out that this method is only applicable for samples with a small size distribution

Ultraviolet Laser Action in Ferromagnetic Zn1−xFexO Nanoneedles

Fe-doped ZnO nanoneedles (NDs) were fabricated by an Ar+ ion sputtering technique operated at room temperature. The as-grown samples show both ferromagnetic and lasing properties. The saturated magnetization moment was measured from 0.307 to 0.659 emu cm−3 at the field of 10 kOe with various Fe concentrations. Intense ultraviolet random lasing emission was observed from Zn1 − xFexO NDs at room temperature. The X-ray photoelectron spectroscopy result reveals that the doped Fe atoms occupy the Zn sites and lead to a decrease in oxygen deficiency

Growth of Comb-like ZnO Nanostructures for Dye-sensitized Solar Cells Applications

Dye-sensitized solar cells (DSSCs) were fabricated by using well-crystallized ZnO nanocombs directly grown onto the fluorine-doped tin oxide (FTO) via noncatalytic thermal evaporation process. The thin films of as-grown ZnO nanocombs were used as photoanode materials to fabricate the DSSCs, which exhibited an overall light to electricity conversion efficiency of 0.68% with a fill factor of 34%, short-circuit current of 3.14 mA/cm2, and open-circuit voltage of 0.671 V. To the best of our knowledge, this is first report in which thin film of ZnO nanocombs was used as photoanode materials to fabricate the DSSCs