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The article offers information on a study regarding stratospheric pathway linking a colder Siberia to Barents-Kara Sea sea ice loss. It mentions that atmospheric general circulation model (AGCM) experiments to assess the explicit contribution of the stratospheric pathway to the Siberian cold anomaly and extreme cold events. It states that the zonal means of temperature, zonal wind, meridional wind, and specific humidity above 90 hPa were nudged toward those in the CTRL.

Previous studies have identified two important features of summertime thermodynamics: 1) a significant correlation between the low-level distribution of equivalent potential temperature θe and the potential temperature θ of the extratropical tropopause and 2) a northwestward shift of the maximum tropopause θ relative to the maximum low-level θe. Here, the authors hypothesize these two features occur because of the Asian monsoon circulation. The hypothesis is examined using a set of idealized prescribed sea surface temperature (SST) aquaplanel simulations. Simulations with a zonally symmetric background climate exhibit a weak moisture-tropopause correlation. A significant correlation and northwestward shift occurs when a zonal wave-1 SST perturbation is introduced in the Northern Hemisphere subtropics. The equivalent zonal-mean subtropical warming does not produce a significant correlation. A mechanism is proposed to explain the moislure-tropopause connection that involves the circulation response to zonally asymmetric surface heating and its impact on the tropopause defined by the 2-potentialvorticity- unit (PVU; 1 PVU = 10-6 K kg-1 m2 s-1) surface. While the circulation response to diabatic heating is well known, here the focus is on the implications for the tropopause. Consistent with previous research, surface heating increases the low-level θe and produces low-level convergence and a cyclonic circulation. The low-level convergence is coupled with upper-level divergence via convection and produces an upper-level anticyclonic circulation consistent with Sverdrup balance. The anticyclonic vorticity lowers the PV northwest of the surface heating via Rossby wave dynamics. The decreased PV leads to a northwestward shift of the 2-PVU surface on fixed pressure levels. The θ value to the northwest of the surface heating is higher, and consequently the maximum tropopause θ increases. [ABSTRACT FROM AUTHOR]

The 1987 Montreal Protocol regulating emissions of chlorofluorocarbons (CFCs) and other ozone-depleting substances (ODSs) was motivated primarily by the harm to human health and ecosystems arising from increased exposure to ultraviolet-B (UV-B) radiation associated with depletion of the ozone layer. It is now known that the Montreal Protocol has helped reduce radiative forcing of the climate system since CFCs are greenhouse gases (GHGs), and that ozone depletion (which is now on the verge of reversing) has been the dominant driver of atmospheric circulation changes in the Southern Hemisphere in the last half century. This paper demonstrates that the Montreal Protocol also significantly protects Earth's hydroclimate. Using the Community Atmospheric Model, version 3 (CAM3), coupled to a simple mixed layer ocean, it is shown that in the "world avoided" (i.e., with CFC emissions not regulated), the subtropical dry zones would be substantially drier, and the middle- and high-latitude regions considerably wetter in the coming decade (2020-29) than in a world without ozone depletion. Surprisingly, these changes are very similar, in both pattern and magnitude, to those caused by projected increases in GHG concentrations over the same period. It is further shown that, by dynamical and thermodynamical mechanisms, both the stratospheric ozone depletion and increased CFCs contribute to these changes. The results herein imply that, as a consequence of the Montreal Protocol, changes in the hydrological cycle in the coming decade will be only half as strong as what they otherwise would be. [ABSTRACT FROM AUTHOR]

In this paper, we completely characterize the order boundedness of weighted composition operators between differentweightedDirichlet spaces and different derivative Hardy spaces, which generalizes the previousworks done by Sharma et al. [ABSTRACT FROM AUTHOR]

• ·Shear tests on gypsum board-to-CFS stud screw connections were performed. • ·A screw-sheathing abrasion theory was proposed. • ·Seismic damage model for gypsum board-to-CFS stud screw connections was established. First, a cyclic loading method of gypsum board-to-cold-formed steel (CFS) stud screw connections was explored, and the impact of ground motion duration was considered. Then, the correlation between the shear behavior of the screw connections and ground motion duration was investigated. Afterward, a screw-sheathing abrasion theory was proposed, and the shear performance degradation mechanism of the screw connections was further revealed. Moreover, a method for determining the load-deformation relationship of the screw connections was established. Ultimately, a seismic damage model for gypsum board-to-CFS stud screw connections considering the impact of ground motion duration was established based on an improvement of the Park-Ang seismic damage model. The results are as follows: (1) The load-deformation curves of the screw connections show nonlinear characteristics accompanied by strength and stiffness degradation and pinching. The primary control of the load-deformation curves and shear damage of the screw connections is extrusion of the screw from the gypsum board. (2) The shear damage of the screw connections is positively correlated with the number of loading cycles originating from long-duration ground motions. (3) A load-deformation relationship of gypsum board-to-CFS stud screw connections considering the influence of the loading path can be established accurately through the proposed screw-sheathing abrasion theory. (4) The proposed seismic damage model reflects the change in the ultimate energy dissipation capacity of gypsum board-to-CFS stud screw connections with a hysteretic energy dissipation process. The damage development of the screw connections can be accurately described, indicating good applicability to sheathing-to-CFS stud screw connections dominated by sheathing bearing failure. [ABSTRACT FROM AUTHOR]

A sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, followed by a 96-well protein precipitation, has been developed and fully validated for the determination of Phakellistatin 13 (PK13), a new cyclic heptapeptide isolated from the sponge Phakellia fusca Thiele, in rat plasma. After protein precipitation of the plasma samples (50 μL) in a 96-well plate by methanol (200 μL) containing the internal standard Pseudostellarin B (20 ng/mL), the plate was vortex mixed for 3 min. Following filtration for 5 min, the filtrate was directly injected into the LC-MS/MS system. The analytes were separated on an XB-C18 analytical column (5 µm, 50 mm × 4.6 mm i.d.) using an eluent of methanol–water (85:15, v/ v) and detected by electrospray ionization mass spectrometry in the negative multiple reaction monitoring mode with a chromatographic run time of 5.0 min. The method was sensitive with a lower limit of quantification (LLOQ) of 0.1 ng/mL, with good linearity ( r > 0.999) over the quantitation range of 0.1–5 ng/mL. The validation results demonstrated that this method was significantly specific, accurate, precise, and was successfully applied in measuring levels of PK13 in rat plasma following intravenous administration of 20, 50, and 100 µg/kg of peptide in rats, respectively, which was suitable for the preclinical pharmacokinetic studies on PK13. [ABSTRACT FROM AUTHOR]