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Deep Structure of the Continental Plate in the South-Central Chilean Margin: Metamorphic Wedge and Implications for Megathrust Earthquakes

We study the deep structure of the continental wedge along the south-central Chilean convergent margin based on a joint interpretation of wide-angle reflection and refraction seismic phases acquired between the southern part of the Maule 2010 (36°S) and the northern part of the Valdivia 1960 (41°S) earthquake rupture areas. When combined with results of previous seismic studies, our results provide new insights into the deep structure (to 15–20 km) of the overriding, continental South American plate. We observe a latitudinal variation of P wave velocity, interpreted in terms of the distribution of Permo-Triassic metamorphic complex near the coast, and deep reflectors at the base of these metamorphic units. A change in the observed deep structural style near 38°S suggests a segmentation in the interplate frictional properties between the Maule and Valdivia earthquakes rupture zones. This regional change in the continental wedge structure indicates a spatial correlation between the coseismic ruptures of large earthquakes (e.g., the 1960 and 2010 megathrust earthquakes) and the rheology/lithology along the interplate boundary.

Journal of Geophysical Research: Solid Earth SCI,SCIE | 2021 | 126 (7)

Generative Adversarial Networks in Computer Vision: A Survey and Taxonomy

Generative adversarial networks (GANs) have been extensively studied in the past few years. Arguably their most significant impact has been in the area of computer vision where great advances have been made in challenges such as plausible image generation, image-to-image translation, facial attribute manipulation, and similar domains. Despite the significant successes achieved to date, applying GANs to real-world problems still poses significant challenges, three of which we focus on here. These are as follows: (1) the generation of high quality images, (2) diversity of image generation, and (3) stabilizing training. Focusing on the degree to which popular GAN technologies have made progress against these challenges, we provide a detailed review of the state-of-the-art in GAN-related research in the published scientific literature. We further structure this review through a convenient taxonomy we have adopted based on variations in GAN architectures and loss functions. While several reviews for GANs have been presented to date, none have considered the status of this field based on their progress toward addressing practical challenges relevant to computer vision. Accordingly, we review and critically discuss the most popular architecture-variant, and loss-variant GANs, for tackling these challenges. Our objective is to provide an overview as well as a critical analysis of the status of GAN research in terms of relevant progress toward critical computer vision application requirements. As we do this we also discuss the most compelling applications in computer vision in which GANs have demonstrated considerable success along with some suggestions for future research directions. Codes related to the GAN-variants studied in this work is summarized on https://github.com/sheqi/GAN_Review.

Association for Computing Machinery EI,SCI,SCIE | 2021 | 54 (2)

In-orbit preliminary results from the open-source educational nanosatellite FloripaSat-I

This paper presents the embedded systems along with the first in-orbit results of FloripaSat-I, a complete CubeSat mission developed at the Federal University of Santa Catarina, Brazil. The satellite’s service module has three main subsystems, each with an embedded processor and its peripherals. This paper presents an overview of the nanosatellite architecture designed for the mission, including the embedded systems, functionalities, and components. Launched in December 2019 atop a Chinese Long March 4B rocket, FloripaSat-I has been since then transmitting mission data, which is a metric used to validate its open-source service platform through flight heritage. The results collected in orbit are presented and discussed, as well as the student’s perception about the challenges in the project. With the analysis of the results, it is possible to identify technical points to be improved by external groups with interest to reuse the open-source service platform for the next missions, and the impact that this teaching–learning methodology has in the students.

Acta Astronautica EI,SCIE | 2021 | 188

Global Coordination in Plant Physiological and Rooting Strategies in Response to Water Stress

Plants employ a range of strategies to modulate the impact of water stress, including changes to rooting depth and hydraulic conductance (e.g., xylem conductance). However, it is still poorly understood how these strategies vary in relation to climate and land cover types and how they could coordinate globally. Based on daily microwave vegetation optical depth (VOD) from AMSR-E and AMSR2 over 2002–2011, we estimate two proxies for stress regulation: (a) an effective plant rooting depth and (b) the effective plant hydraulic conductance to delineate two strategies: deep rooting and strong physiological regulation. We find that plants with deeper (e.g., evergreen/deciduous broadleaf forest) are mostly distributed in warm or wet regions, and maintain a relatively steady nighttime VOD because of access to deeper water. Taller plants exhibit greater drop in daytime VOD due to their greater physiological vulnerability. While physiological regulation appears to be the dominant water stress regulation strategy at Northern high latitudes where open shrubland and (woody) savannas are distributed, this physiological regulation is coupled with deep rooting in forest and (woody) savanna areas in the tropics, Eastern US, and Southeastern China. Meanwhile, grasslands in the Western US, Central Asia, Northeastern China, and Mongolia Plateau may be the regions most susceptible to water stress impact because neither water stress mitigation strategy is present. This new framework paves the road for a better understanding of plant water stress strategies at the global scale, and for enhancing large-scale drought prediction and drought impact assessment in Earth system models by improving plant water stress response.

Global biogeochemical cycles SCI,SCIE | 2021 | 35 (7)

Transcriptome sequencing revealed the molecular mechanism of response of pearl millet root to heat stress

High temperature is an environmental factor that affects plant growth and productivity. It is very important to study the changes in plant roots under heat stress (HS) to discover key heat response genes and improve the heat tolerance of plants. Pearl millet is utilized for food, livestock feed and bioenergy materials and is highly tolerant to HS. However, research on the response mechanism of pearl millet roots to HS is limited. In this study, we performed physiological index determination and RNA-seq on the roots of pearl millet under HS (40/35°C) at 1, 3 and 7 hr. The number of differentially expressed genes (DEGs) at 3 hr was the highest (8,479), followed by 1 hr (6,250) and 7 hr (5,167). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of DEGs revealed that the endoplasmic reticulum (ER) stress and trehalose synthesis pathways were the major responsive pathways after 1 and 3 hr of HS. This study revealed the underlying molecular mechanism of root response to high temperature stress in pearl millet and provided useful information for identifying heat-resistant genes and breeding heat-resistant plants.

Journal of agronomy and crop science (1986. Internet) SCI,SCIE | 2021 | 207 (4)