7,351 research outputs found

    Distribution of corneal and ocular spherical aberrations in eyes with cataract in the Taiwanese population

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    AbstractPurposeTo investigate the distribution of corneal and ocular spherical aberrations (SAs) in eyes with cataract in the Taiwanese population.MethodsCorneal and ocular SAs were measured in the central 6-mm optical zone using wavefront aberrometry. Axial length (AL) and keratometry (K) were also evaluated in each eye.ResultsA total of 413 eyes in 234 patients were analyzed. The mean age of the patients was 66.8 ± 10.64 years. The mean AL and K values were 24.32 mm and 44.08 D, respectively. The mean corneal SA was 0.307 ± 0.135 μm and ocular SA was −0.042 ± 0.487 μm. Ocular and corneal SAs were significantly correlated (r2 = 0.04, p < 0.001). Corneal and ocular SAs were not significantly correlated with K (p = 0.096 and p = 0.634, respectively), but were significantly correlated with AL (p < 0.001). Multilinear regression showed that corneal SAs and age were the dependent variables that predicted ocular SAs (r2 = 0.143, F = 13.65, p < 0.01), especially in patients who were aged > 50 years, for whom a strongly significant positive correlation was found (r2 = 0.102, F = 11.10, p < 0.001).ConclusionCorneal and ocular SAs varied among cataract patients and correlated with AL. After 50 years of age, ocular SAs increased significantly because of an increase in internal (lenticular) SAs. Corneal SAs in Taiwanese patients were larger than those in Japanese patients and similar to those in Chinese and Malaysian populations. Preoperative measurement of wavefront aberrations is necessary to select which aspherical intraocular lenses are most suitable for achieving better postoperative visual quality

    Controlling complex networks: How much energy is needed?

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    The outstanding problem of controlling complex networks is relevant to many areas of science and engineering, and has the potential to generate technological breakthroughs as well. We address the physically important issue of the energy required for achieving control by deriving and validating scaling laws for the lower and upper energy bounds. These bounds represent a reasonable estimate of the energy cost associated with control, and provide a step forward from the current research on controllability toward ultimate control of complex networked dynamical systems.Comment: 4 pages paper + 5 pages supplement. accepted for publication in Physical Review Letters; http://link.aps.org/doi/10.1103/PhysRevLett.108.21870

    Development of the Risk Management Mechanism of an Enterprise Resource Planning System based on Work System Method

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    This study collects 24 risk-management-relevant research papers published between 2000 and 2010 to elicit significant risk factors and thus develop the risk management mechanism of an enterprise resource planning (ERP) system. The study adopts the grounded theory and conducts an expert questionnaire in order to report its findings on 49 risk factors. Based on the work system method, the identified factors are classified into nine categories and a risk management mechanism is developed thereafter. Finally, to examine the feasibility of the mechanism, two case studies are further investigated. The developed mechanism is found to be a convenient, quick, and proper ERP system risk management tool that can assist enterprises in identifying, analyzing, assessing, and responding to potential risks

    Attentive filtering networks for audio replay attack detection

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    An attacker may use a variety of techniques to fool an automatic speaker verification system into accepting them as a genuine user. Anti-spoofing methods meanwhile aim to make the system robust against such attacks. The ASVspoof 2017 Challenge focused specifically on replay attacks, with the intention of measuring the limits of replay attack detection as well as developing countermeasures against them. In this work, we propose our replay attacks detection system - Attentive Filtering Network, which is composed of an attention-based filtering mechanism that enhances feature representations in both the frequency and time domains, and a ResNet-based classifier. We show that the network enables us to visualize the automatically acquired feature representations that are helpful for spoofing detection. Attentive Filtering Network attains an evaluation EER of 8.99%\% on the ASVspoof 2017 Version 2.0 dataset. With system fusion, our best system further obtains a 30%\% relative improvement over the ASVspoof 2017 enhanced baseline system.Comment: Submitted to ICASSP 201

    Slow conduction and gap junction remodeling in murine ventricle after chronic alcohol ingestion

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    <p>Abstract</p> <p>Background</p> <p>Long-term heavy alcohol drinkers are prone to the development of cardiac arrhythmia. To understand the mechanisms, we evaluated the cardiac structural and electrophysiological changes in mice chronically drinking excessive alcohol.</p> <p>Results</p> <p>Male C57BL/6J mice were given 36% alcohol in the drinking water. Those given blank water were used as control. Twelve weeks later, the phenotypic characteristics of the heart, including gap junctions and electrical properties were examined. In the alcohol group the ventricles contained a smaller size of cardiomyocytes and a higher density of capillary networks, compared to the control. Western blots showed that, after drinking alcohol, the content of connexin43 (Cx43) protein in the left ventricle was increased by 18% (p < 0.05). Consistently, immunoconfocal microscopy demonstrated that Cx43 gap junctions were up-regulated in the alcohol group with a disorganized distribution, compared to the control. Optical mapping showed that the alcohol group had a reduced conduction velocity (40 ± 18 vs 60 ± 7 cm/sec, p < 0.05) and a higher incidence of ventricular tachyarrhythmia (62% vs 30%, p < 0.05).</p> <p>Conclusion</p> <p>Long-term excessive alcohol intake resulted in extensive cardiac remodeling, including changes in expression and distribution of gap junctions, growth of capillary network, reduction of cardiomyocyte size, and decrease of myocardial conduction.</p
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