Izumi fever (IF), also known as Far East scarlet-like fever (FESLF), is caused by Yersinia pseudotuberculosis and it has clinical features resembling those of Kawasaki disease (KD). As both diseases ...are rare in adolescents and young adults, it is challenging to recognize them, thus often leading to a delayed diagnosis. We herein present two cases of IF or FESLF (IF/FESLF). The first case was misdiagnosed as KD, which led to a diagnostic delay. The second case was recognized earlier owing to our experience with the first case. Although cultures were negative in both cases, presumably due to the prior use of antimicrobial agents, our clinical suspicion and a paired serological assay for anti-Yersinia pseudotuberculosis antibodies finally led to a successful diagnosis.
The prevalence of antibiotic resistance in 376 Escherichia coli (E. coli) isolates from fecal samples of Hooded and White-naped cranes was investigated on the Izumi plain in Kagoshima prefecture, ...Japan, during winter 2016 and 2017. Resistance to oxytetracycline, ampicillin, and nalidixic acid were observed in 10.9%, 3.1–4.4%, and 2.1–7.7% of isolates, respectively. Since the previous surveillance in 2007, isolation rates of antibiotic-resistant E. coli recovered from wild cranes have remained at significantly low levels compared with those in Japanese livestock. Our results indicate that surveillance of antibiotic-resistant E. coli from wild cranes wintering in the Izumi plain could be a useful strategy to indicate natural environmental pollution by antibiotic-resistant bacteria in the environment.
The Median Tectonic Line (MTL) in Southwest Japan, a major east‐west trending arc‐parallel fault, has been defined as the boundary fault between the Cretaceous Sambagawa metamorphic rocks and the ...Ryoke granitic and metamorphic rocks, which are unconformably covered by the Upper Cretaceous Izumi Group. Based on the detailed fieldwork and microstructural studies of fault rocks, we reconstruct the kinematic history along the MTL during the Paleogene, which can be divided into the Ichinokawa and pre‐Tobe phases. While the Ichinokawa phase is defined by large‐scale, top‐to‐the‐north normal faulting, the pre‐Tobe phase is represented by large‐scale, high‐angle right‐stepping en échelon faults almost parallel to the MTL in the Upper Cretaceous Izumi Group. We found that left‐handed en échelon folds have developed along the right‐stepping faults, which contain 25–60 m wide cataclasite and fault gouge. Both map scale en échelon folds and microstructures (e.g., composite planar structures) in the fault rocks suggest that they were formed by sinistral‐reverse faulting with top‐to‐the‐SW kinematics. Furthermore, based on the new K‐Ar age dating of authigenic illite from the fault gouge along the MTL and right‐stepping faults, it can be concluded that the MTL was activated in two discrete stages at approximately 59 Ma (Ichinokawa phase) and 47–46 Ma (pre‐Tobe phase). Based on these results, we reappraise the kinematic framework of the MTL in the Paleogene, which can be interpreted as the record of the movements of the subducting oceanic plate relative to the continental plate.
Key Points
The kinematics of the Median Tectonic Line (MTL), a major arc‐parallel fault in SW Japan, are investigated and dated by the K‐Ar method
In the Paleogene, large‐scale normal faulting at approximately 59 Ma is followed by sinistral‐reverse faulting at 47‐46 Ma along the MTL
These kinematic histories of the MTL are well‐correlated with the reconstructed plate motion in the Pacific region in geological time
We determine the features and distribution of fault rocks along the Median Tectonic Line (MTL), SW Japan, to establish the 3D architecture of the fault zone across the brittle–plastic transition. ...Cataclasites exposed close to the lithological boundary fault (the MTL) can be divided into those formed by sinistral faulting at temperatures of ∼300 °C and those formed by dextral faulting at ∼250 °C. Mylonites distributed to the north of the cataclasites were formed by sinistral faulting and can be divided into lower-temperature mylonite (L-T mylonite) close to the MTL and higher-temperature mylonite (H-T mylonite) distant from the MTL, where deformation temperatures were lower and higher than 400 °C, respectively. Structures formed by sinistral faulting are oblique to those formed by dextral faulting, indicating that the former structures are older than the latter. Structures formed by sinistral faulting underwent deformation around the brittle–plastic transition. Thus, the MTL fault zone records deformation through a crustal section. Microstructural observations suggest that the differential stress just below the brittle–plastic transition (L-T mylonite) was ∼200 MPa and that this value may not change substantially in the deep crust (H-T mylonite).
•Generate information for a km-scale 3D model of fault-zone architecture.•Identify structures formed by deformation across the brittle-plastic transition.•The studied fault zone records deformation through a crustal section.•Results suggest considerable differential stress below the seismogenic zone.
Pores and cracks have an important role in the evolution of fault rocks because they strongly influence the behavior of the fluids that promote rock alteration and trigger the mechanical instability ...of faults. We used rock physics model inversion of measured elastic wave velocity and porosity to estimate the grain elastic moduli and crack aspect ratios of a range of fault rocks (intact rocks, fractured rocks, transition rocks, and fault gouge) from the Median Tectonic Line in southwest Japan. Our results show distinct gaps in the evolutionary trends of crack aspect ratios and grain elastic moduli from intact rocks to fault rocks. Crack aspect ratios show a nonlinear trend from intact rock to fault gouge, and then these values in fault gouge were considerably higher than in fractured rock and transition rock. In contrast, grain elastic moduli decreased as fracture evolved with the development and subsequent extinction of shear planes and then increased markedly with the formation of fault gouge. Our results show that crack aspect ratios and grain elastic moduli are clearly related to the evolution of shear fabrics in faults. Therefore, they might be useful indicators of fault activity and maturity.
•Elastic wave velocity and porosity are closely related to fault rock evolution.•There is a strong relationship between crack aspect ratio and shear fabric.•Crack aspect ratios and grain elastic moduli are indicators of fault activity and maturity.
Izumi fever (IF), also known as Far East scarlet-like fever (FESLF), is caused by Yersinia pseudotuberculosis and it has clinical features resembling those of Kawasaki disease (KD). As both diseases ...are rare in adolescents and young adults, it is challenging to recognize them, thus often leading to a delayed diagnosis. We herein present two cases of IF or FESLF (IF/FESLF). The first case was misdiagnosed as KD, which led to a diagnostic delay. The second case was recognized earlier owing to our experience with the first case. Although cultures were negative in both cases, presumably due to the prior use of antimicrobial agents, our clinical suspicion and a paired serological assay for anti-Y. pseudotuberculosis antibodies finally led to a successful diagnosis.
For upland ephemeral gullies, gully erosion is strongly related to the formation and migration of cyclic steps. It is necessary to provide insight into the process of cyclic step development to ...accurately predict the pace of landscape evolution and soil loss. Information on the geometry of cyclic steps in subaerial environments is limited, and, to our knowledge, no model of cyclic step development considers plunge pool erosion. In this study, we analyze the geometric features and controlling factors of erosional cyclic steps through meta‐analysis of measured data including new measurements in the Loess Plateau, China. We focus on cyclic step dynamics of fluvial beds controlled by bed shear stress and local plunge pool erosion. We develop a new theory to incorporate plunge pool erosion through adapting existing cyclic step and plunge pool models. Our method agrees with measured data, showing that a larger flow rate leads to larger step length Ld and height Hd and increasing erodibility increases step aspect ratio Ld/Hd. The method is also able to predict how the step length, height, and aspect ratio change with the average channel slope. Our results indicate that plunge pool erosion is an important mechanism of cyclic step evolution. However, plunge pool development alone is not sufficient to explain the wide range of Ld/Hd in the measured data. The posed theory relates to equilibrium conditions and thus cannot consider temporal adjustments in step geometry.
Plain Language Summary
The beds of upland ephemeral gullies often have long profiles with a discontinuous series of upstream‐migrating steps. Channels with these steps show characteristics of water flow and sediment transport that differ from channels where steps are absent. This difference in turn affects the rates of landscape evolution and soil erosion. In the Loess Plateau, China, periodic steps are accompanied by plunge pool erosion below a free overfall. No models to date tie both step and plunge pool formation. In this study, we present geometric data of steps measured in a small watershed of the Loess Plateau. We develop a theory that models periodic steps with plunge pool erosion. We identify the factors that control step geometry through meta‐analysis of measured data and numerical modeling. The results show that discharge, bed erodibility, and slope are coupled with each other in the establishment of step‐pool geometry. Furthermore, we find that plunge pool erosion is a key mechanism that controls the trend between step height and slope. However, the new model fails to completely describe the wide range of values of step length divided by step height, probably because it does not consider the change in step geometry over time.
Key Points
Length and height of cyclic steps increase with flow rate in measured data and model predictions
Smaller channel slope and larger bed erodibility result in a larger step aspect ratio in measured data and model predictions
Adding plunge pool erosion improves model predictions for step length, height, and aspect ratio relative to the average channel slope
We have elucidated retention of primary Sr isotopic ratios in source rocks to sediments and sedimentary rocks during repeated sedimentation recycling. Twenty-three fine stream sediments (<180 μm) in ...Awajishima Island were used for the study. The 87Rb/86Sr and 87Sr/86Sr of stream sediments originated from Cretaceous Ryoke granitic rocks and Cretaceous sedimentary rocks (Izumi Group) were similar to those of the respective source rocks. Incidentally, the 87Rb/86Sr-87Sr/86Sr of stream sediments in Awajishima Island suggests that Cretaceous felsic igneous rocks are the dominant source of clastics in Izumi Group. Stream sediments derived from Neogene and Quaternary sediments, which are originated from granitic rocks and Izumi Group, had comparable isotopic ratios to those of the respective primitive source rocks. Accordingly, 87Rb/86Sr and 87Sr/86Sr can be retained during the repeated recycling process of sediments and sedimentary rocks. Stream sediment is presumed to consist of clastics supplied from respective lithologies according to their exposed areas. However, 87Sr/86Sr of stream sediment is not comparable to the values calculated from exposed areas of lithologies and isotopic data of parent rocks. The result suggests that amount of sedimentation denudation and production differs among different lithologies and is not simply proportional to their exposed areas.
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