Spatially variable syn- and post-Alleghanian exhumation of the central Appalachian Mountains from zircon (U-Th)/He thermochronology

To assess spatial and temporal patterns of Phanerozoic orogenic burial and subsequent exhumation in the central Appalachian Mountains, we present mid-temperature zircon (U-Th)/He (ZHe; closure temperature [TC] = 140–200 °C) dates for 10 samples along a 225 km, strike-perpendicular transect spanning the Appalachian Plateau, Valley and Ridge, Blue Ridge, and Piedmont physiographic provinces in West Virginia and western Virginia. Ranges of single-grain ZHe dates exhibit an eastward younging trend from 455–358 Ma in the Pennsylvanian Appalachian Plateau to 336–209 Ma in the Valley and Ridge, 298–217 Ma in the Blue Ridge, and 186–121 Ma in the Piedmont. Within the Pennsylvanian Appalachian Plateau, detrital ZHe dates are older than corresponding depositional ages, thus limiting postdepositional burial temperatures to less than 160 °C. These ZHe dates capture predepositional mid-Paleozoic cooling signatures, indicating provenance from either recycled Taconic or Acadian basin strata or mid-Paleozoic Appalachian terranes. Across the Valley and Ridge and western Blue Ridge provinces, reset Permian detrital ZHe dates feature flat date-effective uranium correlations that suggest rapid Alleghanian cooling initiating prior to 270 Ma. ZHe dates within the Valley and Ridge are more than 100 m.y. older than previously reported regional apatite fission-track dates, reflecting a protracted period of stable post-Alleghanian thermal conditions within the foreland. By contrast, post-Triassic single-grain ZHe dates in the interior Piedmont document rapid postrift cooling, likely resulting from both the relaxation of an elevated geothermal gradient and exhumation from rift-flank uplift. The spatial discontinuity between stable synrift thermal conditions in the Valley and Ridge and rapid cooling in the Piedmont suggests that rift-flank uplift and cooling were concentrated outboard of the foreland within the Piedmont province.

Improvements of 6S Look-Up-Table Based Surface Reflectance Employing Minimum Curvature Surface Method

We propose a methodology employing an interpolation technique on the Second Simulation of a Satellite Signal (6S) look-up table (LUT) to improve surface reflectance retrieval using Himawari-8/Advanced Himawari Imager (AHI). A minimum curvature surface (MCS) technique was used to refine the 6S LUT, and the solar zenith angle (SZA) and viewing zenith angle (VZA) increments were narrowed by 0.5°. The interpolation processing time was relatively short, about 3172 s per channel, and the interpolated xa and xb were well represented by the changes in SZA and VZA. An evaluation of the interpolated xa and xb for six cases revealed a relative mean absolute error of less than 5% for all channels and cases; however, a slight difference was evident for higher values of SZA and VZA. To evaluate the surface reflectance, we compared the surface reflectance derived using 6S LUT with that calculated using 6S only. Application of the interpolated 6S LUT showed a lower relative root mean square error (RRMSE) of 0.65% to 9.29% for all channels, than before interpolation. The improvement in surface reflectance measurements increased with the SZA. For a SZA above 75°, the RRMSE improved significantly for all channels (by 11.33–45.1%). In addition, when the MCS method was applied, the surface reflectance measurements improved without spatial discontinuity and showed good agreement with 6S results in a linear profile analyses. Thus, the method proposed can improve LUT based surface reflectance measurements in less time and increase the availability of surface reflectance data based on geostationary satellites.

City Image Between Gated and Open Residential Areas

City image and self identity are two interrelated notions. Self identity, also referred to as urban related identity, is not solely derived from the physical characteristics of an urban space, but, consists of the social construction founded in the perception of individuals and groups (Lalli & Ploger, 1991). The relationship of the individual with a place is essential as place and space shape human experiences (Chen, 2012). With the trend of gated residential areas emerging in large cities such as Cairo and Alexandria in the late 90s creating a spatial discontinuity and urban fragmentation, this research is examining how open and gated urban residential areas shape place image of New Cairo’s Third Settlement residents.

Negative Space Theory

It is necessary to continue the research on the formation mechanism of gravitation, the formation mechanism of black hole, the formation mechanism of mass, and the mechanism of symmetry breaking. This study is dedicated to establish a new theory, and compare this new theory with the existing theory, testing self-consistency and rationality of this new theory. Based on the observed physical facts, the negative space theory is be put forward according to the principle of scale conservation and spatial discontinuity, that is, space expansion produces positive space and Huazi, and there is a trap field around Huazi. Comparison results show that the negative space theory can better reveal the above physical mechanism, and changed the previous understanding of these physical mechanism, open up a new research direction.

Negative Space Theory

It is necessary to continue the research on the formation mechanism of gravitation, the formation mechanism of black hole, the formation mechanism of mass, and the mechanism of symmetry breaking. This study is dedicated to establish a new theory, and compare this new theory with the existing theory, testing self-consistency and rationality of this new theory. Based on the observed physical facts, the negative space theory is be put forward according to the principle of scale conservation and spatial discontinuity, that is, space expansion produces positive space and Huazi, and there is a trap field around Huazi. Comparison results show that the negative space theory can better reveal the above physical mechanism, and changed the previous understanding of these physical mechanism, open up a new research direction.

Quantitative Analysis of Quantum Mechanics/Molecular Mechanics Boundary Artifacts and the correction in Adaptive QM/MM Methods

The incorporation of quantum chemical effects of solvation into molecular dynamics simulation has been a challenging issue due to solvent diffusion. To this end, various adaptive quantum mechanics/molecular mechanics (QM/MM) methods have been proposed, in which free solvent exchanges are allowed via a flexible switching of their identities between QM and MM models according to their distances from the QM solute. However, temporal and spatial discontinuities that remain in the standard implementations continue to hamper stable and accurate dynamics simulations using adaptive QM/MM approaches. We previously demonstrated that the size-consistent multi-partitioning (SCMP) method achieved temporal continuity while avoiding spatial discontinuities to some extent. In the present study, however, we demonstrate that the residual spatial discontinuity may lead to severe problems under certain conditions; via quantitative analysis, we show that not only adaptive QM/MM but also all multiscale approaches might share these problems implicitly, which have not been investigated in depth so far. To alleviate these artifacts, we propose a correction based on the SCMP approach and conduct benchmark simulations using bulk water systems.

Quantitative Analysis of Quantum Mechanics/Molecular Mechanics Boundary Artifacts and the correction in Adaptive QM/MM Methods

The incorporation of quantum chemical effects of solvation into molecular dynamics simulation has been a challenging issue due to solvent diffusion. To this end, various adaptive quantum mechanics/molecular mechanics (QM/MM) methods have been proposed, in which free solvent exchanges are allowed via a flexible switching of their identities between QM and MM models according to their distances from the QM solute. However, temporal and spatial discontinuities that remain in the standard implementations continue to hamper stable and accurate dynamics simulations using adaptive QM/MM approaches. We previously demonstrated that the size-consistent multi-partitioning (SCMP) method achieved temporal continuity while avoiding spatial discontinuities to some extent. In the present study, however, we demonstrate that the residual spatial discontinuity may lead to severe problems under certain conditions; via quantitative analysis, we show that not only adaptive QM/MM but also all multiscale approaches might share these problems implicitly, which have not been investigated in depth so far. To alleviate these artifacts, we propose a correction based on the SCMP approach and conduct benchmark simulations using bulk water systems.