The Nankai Trough megathrust earthquakes inflicted catastrophic damage on Japanese society and more widely. Most research is aimed at identifying strongly coupled regions that are considered as a ...major source of future disastrous earthquakes. Here we present a b-value map for the entire Nankai Trough zone. The b value, which represents the rate of occurrence of small earthquakes relative to larger ones, is inversely dependent on differential stresses, and has been used to detect highly stressed areas on fault planes in various tectonic situations. A remarkable finding is that the b value is inversely correlated with the slip-deficit rate (SDR). Moreover, the b value for the areas of high SDR in the eastern part is lower than that in the western part, indicating that differential stress on asperities in the eastern part is higher than that in the western part. This may explain the history of the Nankai Trough earthquakes, in which the eastern part tends to rupture first.
We investigated changes in the
b
value of the Gutenberg–Richter’s law in and around the focal areas of earthquakes on March 20 and on May 1, 2021, with magnitude (
M
) 6.9 and 6.8, respectively, ...which occurred off the Pacific coast of Miyagi prefecture, northeastern Japan. We showed that the
b
value in these focal areas had been noticeably small, especially within a few years before the occurrence of the
M
6.9 earthquake in its vicinity, indicating that differential stress had been high in the focal areas. The coseismic slip of the 2011 Tohoku earthquake seems to have stopped just short of the east side of the focus of the
M
6.9 earthquake. Furthermore, the afterslip of the 2011 Tohoku earthquake was relatively small in the focal areas of the
M
6.9 and
M
6.8 earthquakes, compared to the surrounding regions. In addition, the focus of the
M
6.9 earthquake was situated close to the border point where the interplate slip in the period from 2012 through 2021 has been considerably larger on the northern side than on the southern side. The high-stress state inferred by the
b
-value analysis is concordant with those characteristics of interplate slip events. We found that the
M
6.8 earthquake on May 1 occurred near an area where the
b
value remained small, even after the
M
6.9 quake. The ruptured areas by the two earthquakes now seem to almost coincide with the small-
b
-value region that had existed before their occurrence. The
b
value on the east side of the focal areas of the
M
6.9 and
M
6.8 earthquakes which corresponds to the eastern part of the source region of the 1978 off-Miyagi prefecture earthquake was consistently large, while the seismicity enhanced by the two earthquakes also shows a large
b
value, implying that stress in the region has not been very high.
It was shown previously that the sunspot number (SSN) at a point 3 years before the minimum is well correlated with the maximum SSN of the succeeding cycle, and a better correlation is obtained when ...the maximum SSN is replaced by the average SSN over a cycle for which the average SSN is calculated by dividing cycles at a point 3 years before the minimum (Yoshida and Yamagishi, 2010; Yoshida and Sayre, 2012). Following these findings, we demonstrate in this paper that the correlation between the SSN 3 years before the minimum and the amplitude of the coming cycle differs significantly between even-numbered and odd-numbered cycles: the correlation is much better for even-numbered cycles. Further, it is shown that the amplitude of even-numbered cycles is strongly correlated with that of the succeeding odd-numbered cycles, while the correlation between amplitudes of odd-numbered cycles and those of succeeding even-numbered cycles is very poor. Using the excellent correlations, we estimate the maximum SSN of the current cycle 24 at 81.3 and predict the maximum SSN of cycle 25 to be 115.4 ± 11.9. It is of note, however, that a peak of the SSN has been observed in February 2012 and the peak value 66.9 is considerably smaller than the estimated maximum SSN of cycle 24. We conjecture that the second higher peak of the SSN may appear.
Candida auris is a multidrug-resistant and emergent pathogen that has caused healthcare-associated infection outbreaks. Recently, C. auris has spread worldwide; nevertheless, it was unexpectedly rare ...before 2009. Based on the molecular epidemiological analysis, C. auris may independently emerge at specific areas at first and recently may be transmitted to other continents. As C. auris cannot be detected using conventional methods, internally transcribed spacers, D1/D2 regions of the 26S rDNA sequencing, and/or matrix-assisted laser desorption ionization time-of-flight mass spectrometry method can be selected as comparatively accessible choices. Thus, detection of C. auris using the conventional method might be underestimated. In Japan, all C. auris strains were isolated from ear specimen and not from invasive mycoses. Japan strains were classified as an East Asian clade under a single clone. Although colonization, virulence, and infection pattern are almost the same as with other Candida species, its antifungal resistance is different. Fluconazole resistance is notably common, but resistance to all three classes of antifungals (azole, polyene, and echinocandin) rarely exists. Once C. auris is detected, screening, emphasis on hand hygiene adherence, use of single-patient room isolation, contact precaution, surveillance, and eradication from the environment and patients are appropriately required for infection control.
To elucidate clinicopathological characteristics of non-small-cell lung carcinoma (NSCLC) cases carrying RET rearrangements causing oncogenic fusions to identify responders to therapy with RET ...tyrosine kinase inhibitors.
We investigated 1874 patients with carcinomas, including 1620 adenocarcinomas (ADCs), 203 squamous cell carcinomas (SCCs), 8 large cell carcinomas, and 43 sarcomatoid carcinomas (SACs). Fluorescence in situ hybridisation (FISH) and/or reverse transcription-PCR (RT-PCR) were performed to detect RET gene rearrangement.
In all, 22 cases (1.2%) showed RET rearrangements; all cases were of ADC histology. Of the 22 patients, 19 possessed KIF5B-RET fusion genes, whereas 3 possessed CCDC6-RET fusion genes. The RET-rearranged tumours were significantly more common in younger patients (P=0.038) and tended to occur in patients with no history of smoking (P=0.051). In addition, RET rearrangements were not associated with gender, occupational history (particularly radioactive exposure), tumour size, lymph node status, tumour stage, or patient survival. The predominant growth pattern in RET-rearranged ADCs was lepidic in 6 cases, papillary in 9 cases, acinar in 2 cases, micropapillary in 1 case, and solid in 4 cases. Cells with cytoplasmic mucin production were at least focally present in 12 of the 22 (54.5%) RET-rearranged ADC cases. Among the 21 analysed RET-rearranged tumours, RET immunopositivity was observed in 15 cases (71.4%), and was significantly associated with RET rearrangement (P<0.001).
The RET rearrangements were observed in 1.2% of NSCLCs. All cases of RET rearrangement were ADCs. The RET rearrangements were more likely to be observed in younger patients. Although cytoplasmic mucin production was at least focally present in 54.5% of RET-rearranged ADCs, specific histological features were not detected.
The 2016 Kumamoto earthquakes in Kyushu, Japan, started with a magnitude (
M
) 6.5 quake on April 14 on the Hinagu fault zone (FZ), followed by active seismicity including an
M
6.4 quake. Eventually, ...an
M
7.3 quake occurred on April 16 on the Futagawa FZ. We investigated if any sign indicative of the
M
7.3 quake could be found in the space–time changes in seismicity after the
M
6.5 quake. As a quality control, we determined in advance the threshold magnitude, above which all earthquakes are completely recorded. We then showed that the occurrence rate of relatively large (
M
≥ 3) earthquakes significantly decreased 1 day before the
M
7.3 quake. Significance of this decrease was evaluated by one standard deviation of sampled changes in the rate of occurrence. We next confirmed that seismicity with
M
≥ 3 was well modeled by the Omori–Utsu law with
p
~ 1.5 ± 0.3, which indicates that the temporal decay of seismicity was significantly faster than a typical decay with
p
= 1. The larger
p
value was obtained when we used data of the longer time period in the analysis. This significance was confirmed by a bootstrapping approach. Our detailed analysis shows that the large
p
value was caused by the rapid decay of the seismicity in the northern area around the Futagawa FZ. Application of the slope (the
b
value) of the Gutenberg–Richter frequency–magnitude distribution to the spatiotemporal change in the seismicity revealed that the
b
value in the northern area increased significantly, the increase being Δ
b
= 0.3–0.5. Significance was verified by a statistical test of Δ
b
and a test using bootstrapping errors. Based on our findings, combined with the results obtained by a stress inversion analysis performed by the National Research Institute for Earth Science and Disaster Resilience, we suggested that stress near the Futagawa FZ had reduced just prior to the occurrence of the
M
7.3 quake. We proposed, with some other observations, that a reduction in stress might have been induced by growth of the slow slips on the Futagawa FZ.
Graphical Abstract
.
Although poor oral health influences the occurrence of pulmonary infection in elderly people, it is unclear how the degree of oral health is linked to mortality from pulmonary infection. Therefore, ...we evaluated the relationship between oral health and four-year mortality from pneumonia in an elderly Japanese population. The study population consisted of 697 (277 males, 420 females) of the 1282 individuals who were 80 years old in 1997. Data on oral and systemic health were obtained by means of questionnaires, physical examinations, and laboratory blood tests. One hundred eight of the study persons died between 1998 and 2002. Of these, 22 deaths were due to pneumonia. The adjusted mortality due to pneumonia was 3.9 times higher in persons with 10 or more teeth with a probing depth exceeding 4 mm (periodontal pocket) than in those without periodontal pockets. Therefore, the increase in teeth with periodontal pockets in the elderly may be associated with increased mortality from pneumonia.
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