4,137 research outputs found

    Statistical properties of chaotic microcavities in small and large opening cases

    Full text link
    We study the crossover behavior of statistical properties of eigenvalues in a chaotic microcavity with different refractive indices. The level spacing distributions change from Wigner to Poisson distributions as the refractive index of a microcavity decreases. We propose a non-hermitian matrix model with random elements describing the spectral properties of the chaotic microcavity, which exhibits the crossover behaviors as the opening strength increases.Comment: 22 pages, 6 figure

    Quasiattractors in coupled maps and coupled dielectric cavities

    Full text link
    We study the origin of attracting phenomena in the ray dynamics of coupled optical microcavities. To this end we investigate a combined map that is composed of standard and linear map, and a selection rule that defines when which map has to be used. We find that this system shows attracting dynamics, leading exactly to a quasiattractor, due to collapse of phase space. For coupled dielectric disks, we derive the corresponding mapping based on a ray model with deterministic selection rule and study the quasiattractor obtained from it. We also discuss a generalized Poincar\'e surface of section at dielectric interfaces.Comment: 7 pages, 7 figure

    Semantic network analysis of conflict in Korean society regarding the WHO classification of gaming disorder (disease code 6C51)

    Get PDF
    Background: In 2018, the World Health Organization (WHO), in its 11th revision of the International Classification of Diseases (ICD-11), classified ‘gaming disorder’ as a disease. As a result, countries are witnessing conflicts among stakeholders with regard to the introduction of the classification. The objective of this analysis is to identify trends of coverage made by major media outlets in Korea concerning the controversy over the introduction of ‘gaming disorder’ like a disease and, through such an analysis, examine how social perceptions have been formulated in Korea. Methods: Semantic network analysis was deployed to examine the semantic structure of messages delivered by the media. The analysis was conducted to identify what semantic structure and issues were pursued by the media with regard to the introduction of ‘gaming disorder’ as a disease in the context of social debates, by looking at the prominent of words in messages delivered by news media, and the interactive structure among these words. Results: In terms of their prevalence, the main keywords in major media reports were ‘addiction’, ‘WHO’, ‘classification’, ‘industry’, ‘code’, ‘domestic’, ‘objection’, ‘gaming industry’, ‘introduce’, ‘gaming disorder’, and ‘Ministry of Culture, Sports and Tourism/MCST’. The structural characteristics of the entire network of media reports were formed around keywords such as ‘addiction’, ‘WHO’, ‘classification’, ‘objection’, ‘industry’, ‘code’, ‘mental disorder’, and ‘backlash’. Words with high eigenvector centrality were ‘addiction’, ‘WHO’, ‘classification’, ‘industry’, ‘domestic’, ‘code’, ‘objection’, ‘introduce’, ‘controversy’, and ‘Ministry of Culture, Sports and Tourism/MCST’. Following CONCOR analysis, a total of four clusters were formed: Cluster 1 for objection, Cluster 2 for consent, Cluster 3 for expected problems, and Cluster 4 for factors for efforts towards conflict resolution. Conclusions: This research explored social perceptions in Korea regarding the issue of the WHO introducing gaming disorder as a disease, by identifying trends of the media coverage through a semantic network analysis of the media’s asymmetrical data. Through this, despite the inevitable introduction of the system to promote public health, it was shown that there is a sharp conflict between the medical and the game industry and related public organizations in Korea. [Ethiop. J. Health Dev. 2020;34(Special issue-3):67-77] Keywords: Gaming disorder, disease code 6C51, conflicts, media reports, semantic network analysi

    Temperature change in pig rib bone during implant site preparation by low-speed drilling

    Get PDF
    OBJECTIVES: The purpose of this study was to evaluate the temperature change during low-speed drilling using infrared thermography. MATERIAL AND METHODS: Pig ribs were used to provide cortical bone of a similar quality to human mandible. Heat production by three implant drill systems (two conventional drilling systems and one low-speed drilling system) was evaluated by measuring the bone temperature using infrared thermography. Each system had two different bur sizes. The drill systems used were twist drill (2.0 mm/2.5 mm), which establishes the direction of the implant, and finally a 3.0 mm-pilot drill. Thermal images were recorded using the IRI1001 system (Infrared Integrated Systems Ltd.). Baseline temperature was 31±1ºC. Measurements were repeated 10 times, and a static load of 10 kg was applied while drilling. Data were analyzed using descriptive statistics. Statistical analysis was conducted with two-way ANOVA. RESULTS AND CONCLUSIONS: Mean values (n=10 drill sequences) for maximum recorded temperature (Max TºC), change in temperature (ΔTºC) from baseline were as follows. The changes in temperature (ΔTºC) were 1.57ºC and 2.46ºC for the lowest and the highest values, respectively. Drilling at 50 rpm without irrigation did not produce overheating. There was no significant difference in heat production between the 3 implant drill systems (p>;0.05). No implant drill system produced heat exceeding 47ºC, which is the critical temperature for bone necrosis during low-speed drilling. Low-speed drilling without irrigation could be used during implant site preparation

    (1H-Pyrrol-2-ylmethylidene)(3-{[(1H-pyrrol-2-ylmethylidene)amino]methyl}benzyl)amine

    Get PDF
    In the title compound, C18H18N4, the dihedral angles between the pyrrole rings and the phenyl ring are 85.07 (8)° and 77.13 (9)°. Inter­molecular N—H⋯N hydrogen bonds contribute to the stabilization of the crystal packing

    Task complexity interacts with state-space uncertainty in the arbitration between model-based and model-free learning

    Get PDF
    It has previously been shown that the relative reliability of model-based and model-free reinforcement-learning (RL) systems plays a role in the allocation of behavioral control between them. However, the role of task complexity in the arbitration between these two strategies remains largely unknown. Here, using a combination of novel task design, computational modelling, and model-based fMRI analysis, we examined the role of task complexity alongside state-space uncertainty in the arbitration process. Participants tended to increase model-based RL control in response to increasing task complexity. However, they resorted to model-free RL when both uncertainty and task complexity were high, suggesting that these two variables interact during the arbitration process. Computational fMRI revealed that task complexity interacts with neural representations of the reliability of the two systems in the inferior prefrontal cortex

    Recognition of the microbiota by Nod2 contributes to the oral adjuvant activity of cholera toxin through the induction of interleukin-1β

    Full text link
    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152023/1/imm13105_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152023/2/imm13105.pd

    Comparison of implant stability after different implant surface treatments in dog bone

    Get PDF
    OBJECTIVES: The purpose of this investigation was to evaluate the effects of different implant surface treatments on implant stability in dog mandibles. MATERIAL AND METHODS: A total of 30 implants (Dentium Co, Seoul, Korea) were placed in 5 dog mandibles. Bone quality was assessed at each site. Implant stability was evaluated using 2 different methods. An OsstellTM resonance frequency analyzer (RFA) was used to determine the stability at baseline (day 1), and 3, 6 and 10 weeks after surgery. Animals were euthanized 10 weeks after implant installation. Specimens were obtained and submitted to the laboratory processing. Sections were stained with hematoxylin and eosin for histologic and histomorphometric analyses. All implantation sites in dog mandibles demonstrated bone types II and III. RESULTS AND CONCLUSIONS: All implants showed good primary stability at baseline in terms of insertion torque. The results of this study suggest that surface treatment may have significant effects on biological stability 3 weeks after implant placement. Further studies are needed to confirm these initial observations in poor quality bone
    corecore