Standard accretion disk models suggest that the snow line in the solar nebula migrated interior to the Earth’s orbit in a late stage of nebula evolution. In this late stage, a significant amount of ...ice could have been delivered to 1 AU from outer regions in the form of mm to dm-sized pebbles. This raises the question why the present Earth is so depleted of water (with the ocean mass being as small as 0.023% of the Earth mass). Here we quantify the amount of icy pebbles accreted by terrestrial embryos after the migration of the snow line assuming that no mechanism halts the pebble flow in outer disk regions. We use a simplified version of the coagulation equation to calculate the formation and radial inward drift of icy pebbles in a protoplanetary disk. The pebble accretion cross section of an embryo is calculated using analytic expressions presented by recent studies. We find that the final mass and water content of terrestrial embryos strongly depends on the radial extent of the gas disk, the strength of disk turbulence, and the time at which the snow lines arrives at 1 AU. The disk’s radial extent sets the lifetime of the pebble flow, while turbulence determines the density of pebbles at the midplane where the embryos reside. We find that the final water content of the embryos falls below 0.023 wt% only if the disk is compact (<100 AU), turbulence is strong at 1 AU, and the snow line arrives at 1 AU later than 2–4 Myr after disk formation. If the solar nebula extended to 300 AU, initially rocky embryos would have evolved into icy planets of 1–10 Earth masses unless the snow-line migration was slow. If the proto-Earth contained water of ~1 wt% as might be suggested by the density deficit of the Earth’s outer core, the formation of the proto-Earth was possible with weaker turbulence and with earlier (>0.5–2 Myr) snow-line migration.
Aim: Epicardial adipose tissue (EAT) may be associated with arrhythmogenesis. P-wave indices such as P-wave dispersion and P-wave variation indicated a slowed conduction velocity within the atria. ...This study investigated the effect of dapagliflozin on EAT volume and P-wave indices. Methods: In the present ad hoc analysis, 35 patients with type 2 diabetes mellitus and coronary artery disease were classified into dapagliflozin group (n=18) and conventional treatment group (n=17). At baseline, EAT volume, HbA1c and plasma level of tumor necrotic factor-α (TNF-α) levels, echocardiography, and 12-lead electrocardiogram (ECG) were performed. EAT volume was measured using computed tomography. Using 12-lead ECG, P-wave indices were measured. Results: At baseline, EAT volumes in the dapagliflozin and conventional treatment groups were 113±20 and 110±27 cm3, respectively. Not only HbA1c and plasma level of TNF-α but also echocardiography findings including left atrial dimension and P-wave indices were comparable between the two groups. After 6 months, plasma level of TNF-α as well as EAT volume significantly decreased in the dapagliflozin group only. P-wave dispersion and P-wave variation significantly decreased in the dapagliflozin group only (-9.2±8.7 vs. 5.9±19.9 ms, p=0.01; -3.5±3.5 vs. 1.7±5.9 ms, p=0.01). The change in P-wave dispersion correlated with changes in EAT volume and plasma level of TNF-α. In multivariate analysis, the change in EAT volume was an independent determinant of the change in P-wave dispersion. Conclusion: Dapagliflozin reduced plasma level of TNF-α, EAT volume, and P-wave indices, such as P-wave dispersion. The changes in P-wave indices were especially associated with changes in EAT volume.The number and date of registration: UMIN000035660, 24/Jan/2019
Glycosuria produced by sodium-glucose co-transporter-2 (SGLT-2) inhibitors is associated with weight loss. SGLT-2 inhibitors reportedly might reduce the occurrence of cardiovascular events. ...Epicardial adipose tissue (EAT) is a pathogenic fat depot that may be associated with coronary atherosclerosis. The present study evaluated the relationship between an SGLT-2 inhibitor (dapagliflozin) and EAT volume.
In 40 diabetes mellitus patients with coronary artery disease (10 women and 30 men; mean age of all 40 patients was 67.2 ± 5.4 years), EAT volume was compared prospectively between the dapagliflozin treatment group (DG; n = 20) and conventional treatment group (CTG; n = 20) during a 6-month period. EAT was defined as any pixel that had computed tomography attenuation of - 150 to - 30 Hounsfield units within the pericardial sac. Metabolic parameters, including HbA1c, tumor necrotic factor-α (TNF-α), and plasminogen activator inhibitor-1 (PAI-1) levels, were measured at both baseline and 6-months thereafter.
There were no significant differences at baseline of EAT volume and HbA1c, PAI-1, and TNF-α levels between the two treatment groups. After a 6-month follow-up, the change in HbA1c levels in the DG decreased significantly from 7.2 to 6.8%, while body weight decreased significantly in the DG compared with the CTG (- 2.9 ± 3.4 vs. 0.2 ± 2.4 kg, p = 0.01). At the 6-month follow-up, serum PAI-1 levels tended to decline in the DG. In addition, the change in the TNF-α level in the DG was significantly greater than that in the CTG (- 0.5 ± 0.7 vs. 0.03 ± 0.3 pg/ml, p = 0.03). Furthermore, EAT volume significantly decreased in the DG at the 6-month follow-up compared with the CTG (- 16.4 ± 8.3 vs. 4.7 ± 8.8 cm
, p = 0.01). Not only the changes in the EAT volume and body weight, but also those in the EAT volume and TNF-α level, showed significantly positive correlation.
Treatment with dapagliflozin might improve systemic metabolic parameters and decrease the EAT volume in diabetes mellitus patients, possibly contributing to risk reduction in cardiovascular events.
During the coronavirus disease 2019 pandemic, whether endoscopy generates aerosols needs to be determined.
In patients undergoing upper gastrointestinal endoscopy with an enclosure covering their ...heads, 0.3-10-μm aerosols were measured for 60 seconds before, during, and after endoscopy by an optical counter. Whether aerosols increased in the situation with and without endoscopy was examined.
The analysis included 103 consecutive patients undergoing endoscopy and 90 control patients. Aerosols increased significantly during endoscopy compared with the control group. Body mass index and burping were significant factors related to increased aerosols during endoscopy.
Upper gastrointestinal endoscopy was an aerosol-generating procedure.
In industrial clusters that are affected by earthquakes and tsunamis, advance countermeasures are necessary to ensure the continuity of business operations of companies. This article presents the ...results of a questionnaire survey of small- and medium-sized enterprises in Amagasaki City, Hyogo Prefecture, to determine the current status of disaster countermeasures, and a questionnaire survey of residents’ awareness of risks and their current countermeasures.
Tyler (Journal of Physiology 228 (1973) 637–647) reported that the sensitivity function for curvature detection has band-pass characteristics with respect to shape frequency. The shape of this ...function suggests that the curvature detection mechanism might consist of a set of sub-mechanisms each tuned for shape frequencies similar to mechanisms for contrast detection. In Experiment 1, we applied an adaptation for shape frequency to investigate whether shape frequency is the critical feature in curvature detection. We successfully replicated the U shape threshold function reported by Tyler (1973), but found that selective adaptation does not occur for shape frequency. These results suggest that shape frequency is not critical for curvature detection. In Experiment 2, we examined the possibility that curvature detection for the highest sensitivity range is mediated by a displacement process similar to that for Vernier acuity. The results indicate that curvature detection for this range is mediated by a mechanism that is sensitive to spatial displacement, and suggests the existence of a common mechanism for spatial displacement that mediates both curvature and Vernier detections. By comparing our results with those of several previous studies, we concluded that the apparent band-pass characteristic for curvature detection is produced by combining the characteristics of three separate limiting factors: local orientation at lower frequencies, spatial acuity at higher frequencies, and displacement in the highest sensitivity area.
This study proposes a data-driven approach for controlling a dual-rate sampled-data system using the lifting technique, where the sampling interval of the plant output is longer than the holding ...interval of the control input. In the proposed method, the structure of the dual-rate controller is linearized to its controller parameter, and the controller parameter is optimized using noniterative correlation-based tuning. Furthermore, intersample ripples are eliminated because the difference in the control inputs between sampled outputs is weighted. The effectiveness of the proposed method is demonstrated through numerical and experimental examples.
Although Venus is a terrestrial planet similar to Earth, its atmospheric circulation is much different and poorly characterized
. Winds at the cloud top have been measured predominantly on the ...dayside. Prominent poleward drifts have been observed with dayside cloud tracking and interpreted to be caused by thermal tides and a Hadley circulation
; however, the lack of nightside measurements over broad latitudes has prevented the unambiguous characterization of these components. Here we obtain cloud-tracked winds at all local times using thermal infrared images taken by the Venus orbiter Akatsuki, which is sensitive to an altitude of about 65 kilometres
. Prominent equatorward flows are found on the nightside, resulting in null meridional velocities when these are zonally averaged. The velocity structure of the thermal tides was determined without the influence of the Hadley circulation. The semidiurnal tide was found to have an amplitude large enough to contribute to the maintenance of the atmospheric superrotation. The weakness of the mean meridional flow at the cloud top implies that the poleward branch of the Hadley circulation exists above the cloud top and that the equatorward branch exists in the clouds. Our results should shed light on atmospheric superrotation in other celestial bodies.
We provided a new constraint on HCl abundance at the cloud top of Venus by infrared spectroscopy using a cross-dispersed high-resolution echelle spectrograph, iSHELL, mounted on the NASA Infrared ...Telescope Facility (IRTF). This study investigated the inconsistency in HCl abundance between previous ground-based observations and Venus Express solar occultation measurements. Venusian dayside observations at a solar phase angle of ∼90° were conducted during August 6–7, 2018, and August 18–20, 2020 (UT), when the Venusian afternoon and morning sides were visible, respectively. The high spectral resolving power of ∼80,000 and large Doppler shift (∼13 km/s) enabled the measurement of Venusian lines with less contamination by terrestrial lines. We analyzed the H35Cl P(5) and H37Cl P(6) lines at 2775.8 and 2750.1 cm−1, respectively, in the 1–0 band, together with 16O12C18O P- and R-branch lines of the 20001–00001 band, which fell in the same spectral orders as the HCl lines. The 16O12C18O lines were used to derive the cloud top altitude because the upper clouds significantly impacted the retrieval of HCl abundance. The cloud tops had an equatorially symmetric structure. The average altitude was 70.8 ± 0.6 km in the region equatorward of ±30° and decreased toward higher latitudes. The HCl volume mixing ratio was derived as 0.379 ± 0.013 ppm at a probing altitude of 70.6 ± 1.1 km and showed no significant latitudinal dependence within the range of ±70°. A difference of ∼0.02 ppm between 2018 and 2020 would result mainly from temporal variation. The H35Cl/H37Cl abundance ratio was 3.01 ± 0.16, with no prominent latitudinal dependence. The obtained HCl volume mixing ratio agreed with the results of previous ground-based measurements, which were approximately one order of magnitude larger than those derived from Venus Express solar occultation measurements. The systematic uncertainties in our retrieval analysis cannot explain this significant inconsistency. The impact of diffuse light produced from aerosol scattering on the retrieval method for solar occultation measurements should be investigated further to solve this issue.
•HCl abundance at the cloud top of Venus was obtained from IRTF/iSHELL spectra.•HCl mixing ratio was 0.379 ± 0.013 ppmv at a probing altitude of 70.6 ± 1.1 km.•HCl mixing ratio showed no marked latitudinal dependence within the range of ±70°.•HCl mixing ratio agreed with the results of previous ground-based measurements.•HCl mixing ratio was about one order of magnitude larger than the VEX/SOIR results.
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