King Abdullah University of Science and Technology

About: King Abdullah University of Science and Technology is a education organization based out in Jeddah, Saudi Arabia. It is known for research contribution in the topics: Membrane & Catalysis. The organization has 6221 authors who have published 22019 publications receiving 625706 citations. The organization is also known as: KAUST.

Silicon-Compatible Photodetectors: Trends to Monolithically Integrate Photosensors with Chip Technology

Abstract: Encouraged by the increasing requirements of intelligent equipment, silicon integrated circuit–compatible photodetectors that support single-chip photonic–electronic systems have gained considerable progresses. Advanced materials have resulted in enhanced device performance based on traditional photovoltaic effect and photoconductive effect, and novel device designs have catalyzed new working mechanisms combing rapid photoresponse and high responsivity gain. Surprising applications are developed using monolithic photonic–electronic platforms, and the developing integration strategies keep pace with the developing complementary metal-oxide-semiconductor techniques as well as nonsilicon substrates. Here, the recent developments in silicon-compatible photodetectors, both in device advances and their integration routes, are reviewed. Meanwhile, the progresses, challenges, and possible future directions in this field are discussed and concluded.

Production of lightning NOx and its vertical distribution calculated from three‐dimensional cloud‐scale chemical transport model simulations

Abstract: [1] A three-dimensional (3-D) cloud-scale chemical transport model that includes a parameterized source of lightning NOx on the basis of observed flash rates has been used to simulate six midlatitude and subtropical thunderstorms observed during four field projects Production per intracloud (PIC) and cloud-to-ground (PCG) flash is estimated by assuming various values of PIC and PCG for each storm and determining which production scenario yields NOx mixing ratios that compare most favorably with in-cloud aircraft observations We obtain a mean PCG value of 500 moles NO (7 kg N) per flash The results of this analysis also suggest that on average, PIC may be nearly equal to PCG, which is contrary to the common assumption that intracloud flashes are significantly less productive of NO than are cloud-to-ground flashes This study also presents vertical profiles of the mass of lightning NOx after convection based on 3-D cloud-scale model simulations The results suggest that following convection, a large percentage of lightning NOx remains in the middle and upper troposphere where it originated, while only a small percentage is found near the surface The results of this work differ from profiles calculated from 2-D cloud-scale model simulations with a simpler lightning parameterization that were peaked near the surface and in the upper troposphere (referred to as a “C-shaped” profile) The new model results (a backward C-shaped profile) suggest that chemical transport models that assume a C-shaped vertical profile of lightning NOx mass may place too much mass near the surface and too little in the middle troposphere

The spatial patterns of directional phenotypic selection.

Abstract: Local adaptation, adaptive population divergence and speciation are often expected to result from populations evolving in response to spatial variation in selection. Yet, we lack a comprehensive understanding of the major features that characterise the spatial patterns of selection, namely the extent of variation among populations in the strength and direction of selection. Here, we analyse a data set of spatially replicated studies of directional phenotypic selection from natural populations. The data set includes 60 studies, consisting of 3937 estimates of selection across an average of five populations. We performed meta-analyses to explore features characterising spatial variation in directional selection. We found that selection tends to vary mainly in strength and less in direction among populations. Although differences in the direction of selection occur among populations they do so where selection is often weakest, which may limit the potential for ongoing adaptive population divergence. Overall, we also found that spatial variation in selection appears comparable to temporal (annual) variation in selection within populations; however, several deficiencies in available data currently complicate this comparison. We discuss future research needs to further advance our understanding of spatial variation in selection.