No abstract

An observed poleward migration in the average latitude at which tropical cyclones (TCs) achieved their lifetime-maximum intensities (LMIs) was previously explained by changes in the mean meridional environments favorable to storm development linked to tropical expansion and anthropogenic warming. We show that the poleward migration is greatly influenced by basin-to-basin changes in TC frequency associated with multi-decadal variability, particularly for the Northern Hemisphere (NH). The contribution of the frequency changes to the poleward migration is comparable to that of the mean meridional environmental changes. A statistically significant global poleward trend can be identified simply from the frequency changes in each basin. An opposite trend exists in the frequency variations over the past 30 years between the North Atlantic and the eastern North Pacific where climatological mean latitudes of LMI are high (26.1°N) and low (16.5°N), respectively, which is the key factor in driving the frequency contribution. The strong roles of the interbasin frequency changes in the poleward migration also suggest that if the phase of multidecadal variability in the NH is reversed, as found in earlier TC records, the poleward trend could be changed to an opposite, equatorward, trend in the future.

High‐translucency restorative materials are commonly used in the restoration of anterior teeth where aesthetics is a critical factor. In this in vitro study, the impact of mouthwash on the colour stability and surface characteristics of high‐translucency computer‐aided design and computer‐aided manufacturing (CAD‐CAM) dental restorative materials was evaluated. Two‐hundred specimens were fabricated from five high‐translucency CAD‐CAM materials: a resin nano ceramic; a polymer‐infiltrated ceramic network; a feldspathic ceramic; a lithium disilicate glass ceramic; and high‐translucency zirconia. Each group of ceramic specimens was then divided into four subgroups: conventional mouthwash (LISTERINE); whitening mouthwash (LISTERINE Healthy White); chlorhexidine gluconate; and distilled water. Oral rinsing was simulated at 100 rpm for 180 h, representing 15 yr of clinical simulation. The specimens were then evaluated for colour, translucency, gloss, roughness, and surface morphology. Two‐way ANOVA and linear mixed models were used for intergroup comparisons (α = 0.05). The polymer‐infiltrated ceramic network and feldspathic ceramic became brighter, more opaque, less glossy, and rougher after rinsing with the whitening mouthwash. The long‐term use of specific mouthwashes can cause deterioration of the optical and surface properties of high‐translucency CAD‐CAM dental restorations.

No abstract

It is well known that river discharges, winds, ocean currents, and tides are major dynamical factors that determine the distribution and extension of the Changjiang plume (CP) in the Yellow and East China Seas (YECS). Using observations and numerical experiments, this study demonstrates that, in addition to these factors, typhoons in the YECS also play a crucial role in the extension of the CP during the summer season. The hydrographic data observed at the Ieodo Ocean Research Station (IORS) and by a research vessel during the period of Typhoons Ewiniar (0603) and Dianmu (1004) showed that the typhoon‐induced strong vertical mixing modified spatial distribution of the CP significantly, resulting in the delay of the CP's extension by as much as up to 20 days. A series of numerical experiments for Typhoon Dianmu also showed that the typhoon plays a blocking role for the extension of CP for up to 17 days through the vertical mixing process and the change of background winds. In particular, it is found that the delay due to Dianmu in 2010 contributed to the avoidance of potential mass mortality of marine life by preventing the low‐salinity water from spreading to the aquaculture regions near Jeju Island.