Dynamical contribution to formation of an ozone mini hole in the Northern Hemisphere in mid-winter

Ozone mini holes are localized and transient (several days) column ozone amount depletion phenomena which often appear over northern Europe. In early February 1989, the extremely low ozone value of 172 DU was observed by Total Ozone Mapping Spectrometer observation. Quantitative analyses of this event using a forward and backward trajectory method show that the total ozone depletion is by uplift of air throughout the lower stratosphere, whereas the effect of horizontal advection of ozone-poor air from lower latitudes is relatively small. Similar results are obtained for 4 other severe mini hole cases. However, these two dynamical effects cannot fully explain the total ozone depletion, which implies the existence of other possible processes responsible for ozone mini holes

Dynamic Trend of Myocardial Edema in Takotsubo Syndrome: A Serial Cardiac Magnetic Resonance Study

BACKGROUND The wall motion abnormalities of the left ventricle (LV) in takotsubo syndrome (TTS) are known to be transient and completely recover within a few weeks. However, there is little information about the relationship between functional recovery and tissue characteristics. The aim of this study was to investigate the recovery process of TTS using cardiovascular magnetic resonance (CMR). METHODS Consecutive patients with TTS were prospectively enrolled. We performed serial CMR in the acute phase (<72 h after admission), the subacute phase (7-10 days after admission) and the chronic phase (3 months later). To assess the degree of myocardial edema quantitatively, we evaluated the signal intensity of myocardium on T2-weighted images and calculated the signal intensity ratio compared with the skeletal muscle. RESULTS Fifteen patients with TTS were enrolled. CMR demonstrated reduced LV ejection fraction in the acute phase, and it recovered almost completely by the subacute phase. On the other hand, severe myocardial edema was still observed in the subacute phase, associated with increased LV mass. The highest signal intensity ratio in the subacute phase was correlated with the maximum voltage of negative T wave on electrocardiogram (r = 0.57, p = 0.03). CONCLUSIONS In patients with TTS, myocardial edema associated with increased LV mass still remained in the subacute phase despite functional recovery of the LV. Electrocardiogram may be useful to assess the degree of myocardial edema in the subacute phase. Our study suggests that myocardial ischemia might have a central role in developing TTS

Inter-Band Radiometric Comparison and Calibration of ASTER Visible and Near-Infrared Bands

The present study evaluates inter-band radiometric consistency across the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) visible and near-infrared (VNIR) bands and develops an inter-band calibration algorithm to improve radiometric consistency. Inter-band radiometric comparison of current ASTER data shows a root mean square error (RMSE) of 3.8%–5.7% among radiance outputs of spectral bands due primarily to differences between calibration strategies of the NIR band for nadir-looking (Band 3N) and the other two bands (green and red bands, corresponding to Bands 1 and 2). An algorithm for radiometric calibration of Bands 2 and 3N with reference to Band 1 is developed based on the band translation technique and is used to obtain new radiometric calibration coefficients (RCCs) for sensor sensitivity degradation. The systematic errors between radiance outputs are decreased by applying the derived RCCs, which result in reducing the RMSE from 3.8%–5.7% to 2.2%–2.9%. The remaining errors are approximately equal to or smaller than the intrinsic uncertainties of inter-band calibration derived by sensitivity analysis. Improvement of the radiometric consistency would increase the accuracy of band algebra (e.g., vegetation indices) and its application. The algorithm can be used to evaluate inter-band radiometric consistency, as well as for the calibration of other sensors

Global Land Cover Assessment Using Spatial Uniformity Validation Dataset

The Degree Confluence Project (DCP) is a volunteer-based validation dataset that comprises useful information for global land cover map validation. However, there is a problem with using DCP points as validation data for the accuracy assessment of land cover maps. While resolutions of typical global land cover maps are several hundred meters to several kilometers, DCP points can only guarantee an area of several tens of meters that can be confirmed by ground photographs. So, the objective of this study is to create a land cover map validation dataset with added spatial uniformity information using satellite images and DCP points. For this, we devised a new method to semiautomatically guarantee the spatial uniformity of DCP validation data points at any resolution. This method can judge the validation data with guaranteed uniformity with a user’s accuracy of 0.954. Furthermore, we conducted the accuracy assessment for the existing global land cover maps by the DCP validation data with guaranteed spatial uniformity and found that the trends differed by class and region

A New Rough Set Classifier for Numerical Data Based on Reflexive and Antisymmetric Relations

The grade-added rough set (GRS) approach is an extension of the rough set theory proposed by Pawlak to deal with numerical data. However, the GRS has problems with overtraining, unclassified and unnatural results. In this study, we propose a new approach called the directional neighborhood rough set (DNRS) approach to solve the problems of the GRS. The information granules in the DNRS are based on reflexive and antisymmetric relations. Following these relations, new lower and upper approximations are defined. Based on these definitions, we developed a classifier with a three-step algorithm, including DN-lower approximation classification, DN-upper approximation classification, and exceptional processing. Three experiments were conducted using the University of California Irvine (UCI)’s machine learning dataset to demonstrate the effect of each step in the DNRS model, overcoming the problems of the GRS, and achieving more accurate classifiers. The results showed that when the number of dimensions is reduced and both the lower and upper approximation algorithms are used, the DNRS model is more efficient than when the number of dimensions is large. Additionally, it was shown that the DNRS solves the problems of the GRS and the DNRS model is as accurate as existing classifiers

Modal energy propagation method in coupled systems of rigid and flexible structure

Since the noise generated by mechanical structures affects the merchantability, it is important to predict it at the design stage. Statistical energy analysis (SEA), which solves the energy equilibrium equation between subsystems, is widely used to predict structural noise. However, due to the assumption that eigenmodes are treated statistically, SEA is limited to application in the high-frequency range with high mode density, so it is the challenge to develop vibration power flow analysis method for the low- and mid-frequency range. In this study, we propose a modal energy propagation analysis method to evaluate the vibration power flow between the eigenmodes of a subsystem. In this paper, the validity of the theory and the countermeasures to reduce the vibration by controlling the transmitted power between the eigenmodes are verified using a simple test apparatus. As a result, it was shown that the transmitted power between subsystems can be approximated by the summation of the transmitted powers of individual eigenmodes, confirming the validity of the calculation theory. In addition, it was confirmed that the mean square velocity of the subsystem can be reduced by identifying and controlling the transmitted power of individual eigenmodes using this method