Long-Distance Correlation of Boulder Clays

Nature ◽  
1948 ◽  
Vol 161 (4086) ◽  
pp. 287-288 ◽  
Author(s):  
D. F. W. BADEN-POWELL
2021 ◽  
pp. SP512-2021-79
Author(s):  
Xiang-dong Wang ◽  
Sun-rong Yang ◽  
Le Yao ◽  
Tetsuo Sugiyama ◽  
Ke-yi Hu

AbstractRugose corals are one of the major fossil groups in shallow-water environments. They played an important role in dividing and correlating Carboniferous strata during the last century, when regional biostratigraphic schemes were established and may be useful for long-distance correlation. Carboniferous rugose corals document two evolutionary events. One is the Tournaisian recovery event, with abundant occurrences of typical Carboniferous rugose corals such as columellate taxa and a significant diversification of large, dissepimented corals. The other is the changeover of rugose coral composition at the mid-Carboniferous boundary, which is represented by the disappearance of many large dissepimented taxa with complex axial structures and the appearance of typical Pennsylvanian taxa characterized by compound rugose taxa. The biostratigraphic scales for rugose corals show a finer temporal resolution in the Mississippian than in the Pennsylvanian, which was probably caused by the Late Paleozoic Ice Age that resulted in glacial-eustatic changes and a lack of continuous Pennsylvanian carbonate strata. The Pennsylvanian rugose corals are totally missing in the Cimmerian Continent. High-resolution biostratigraphy of rugose corals has so far only achieved in few regions for the Mississippian time scale. In most regions, more detailed taxonomic works and precise correlations between different fossil groups are needed.


2012 ◽  
Vol 81 (3) ◽  
pp. 034501 ◽  
Author(s):  
Shigeru Inagaki ◽  
Tatsuya Kobayashi ◽  
Kimitaka Itoh ◽  
Tokihiko Tokuzawa ◽  
Sanae-I. Itoh ◽  
...  

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4182
Author(s):  
Haijing Sun ◽  
Anna Wang ◽  
Wenhui Wang ◽  
Chen Liu

The early diagnosis of Alzheimer’s disease (AD) can allow patients to take preventive measures before irreversible brain damage occurs. It can be seen from cross-sectional imaging studies of AD that the features of the lesion areas in AD patients, as observed by magnetic resonance imaging (MRI), show significant variation, and these features are distributed throughout the image space. Since the convolutional layer of the general convolutional neural network (CNN) cannot satisfactorily extract long-distance correlation in the feature space, a deep residual network (ResNet) model, based on spatial transformer networks (STN) and the non-local attention mechanism, is proposed in this study for the early diagnosis of AD. In this ResNet model, a new Mish activation function is selected in the ResNet-50 backbone to replace the Relu function, STN is introduced between the input layer and the improved ResNet-50 backbone, and a non-local attention mechanism is introduced between the fourth and the fifth stages of the improved ResNet-50 backbone. This ResNet model can extract more information from the layers by deepening the network structure through deep ResNet. The introduced STN can transform the spatial information in MRI images of Alzheimer’s patients into another space and retain the key information. The introduced non-local attention mechanism can find the relationship between the lesion areas and normal areas in the feature space. This model can solve the problem of local information loss in traditional CNN and can extract the long-distance correlation in feature space. The proposed method was validated using the ADNI (Alzheimer’s disease neuroimaging initiative) experimental dataset, and compared with several models. The experimental results show that the classification accuracy of the algorithm proposed in this study can reach 97.1%, the macro precision can reach 95.5%, the macro recall can reach 95.3%, and the macro F1 value can reach 95.4%. The proposed model is more effective than other algorithms.


2008 ◽  
Vol 100 (21) ◽  
Author(s):  
M. A. Pedrosa ◽  
C. Silva ◽  
C. Hidalgo ◽  
B. A. Carreras ◽  
R. O. Orozco ◽  
...  

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