Deep Gradient Learning for Efficient Camouflaged Object Detection

This paper introduces DGNet, a novel deep framework that exploits objectgradient supervision for camouflaged object detection (COD). It decouples thetask into two connected branches, i.e., a context and a texture encoder. Theessential connection is the gradient-induced transition, representing a softgrouping between context and texture features. Benefiting from the simple butefficient framework, DGNet outperforms existing state-of-the-art COD models bya large margin. Notably, our efficient version, DGNet-S, runs in real-time (80fps) and achieves comparable results to the cutting-edge modelJCSOD-CVPR$_{21}$ with only 6.82% parameters. Application results also showthat the proposed DGNet performs well in polyp segmentation, defect detection,and transparent object segmentation tasks. Codes will be made available athttps://github.com/GewelsJI/DGNet.<br

Sustainable Land Management (SLM) Practices in Drylands: How Do They Address Desertification Threats?

Managing land sustainably is a huge challenge, especially under harsh climatic conditions such as those found in drylands. The socio-economic situation can also pose challenges, as dryland regions are often characterized by remoteness, marginality, low-productive farming, weak institutions, and even conflict. With threats from climate change, disputes over water, competing claims on land, and migration increasing worldwide, the demands for sustainable land management (SLM) measures will only increase in the future. Within the EU-funded DESIRE project, researchers and stakeholders jointly identified existing SLM technologies and approaches in 17 dryland study sites located in the Mediterranean and around the world. In order to evaluate and share this valuable SLM experience, local researchers documented the SLM technologies and approaches in collaboration with land users, utilizing the internationally recognized WOCAT questionnaires. This article provides an analysis of 30 technologies and 8 approaches, enabling an initial evaluation of how SLM addresses prevalent dryland threats, such as water scarcity, soil degradation, vegetation degradation and low production, climate change, resource use conflicts, and migration. Among the impacts attributed to the documented technologies, those mentioned most were diversified and enhanced production and better management of water and soil degradation, whether through water harvesting, improving soil moisture, or reducing runoff. Favorable local-scale cost-benefit relationships were mainly found when considered over the long term. Nevertheless, SLM was found to improve people's livelihoods and prevent further outmigration. More field research is needed to reinforce expert assessments of SLM impacts and provide the necessary evidence-based rationale for investing in SLM

Quantification of the impact in mid-latitudes of chemical ozone depletion in the 1999/2000 Arctic polar vortex prior to the vortex breakup

International audienceFor the winter 1999/2000 transport of air masses out of the vortex to mid-latitudes and ozone destruction inside and outside the northern polar vortex is studied to quantify the impact of earlier winter (before March) polar ozone destruction on mid-latitude ozone. Nearly 112 000 trajectories are started on 1 December 1999 on 6 different potential temperature levels between 500?600 K and for a subset of these trajectories photo-chemical box-model calculations are performed. We linked a decline of ?0.9% of mid-latitude ozone in this layer occurring in January and February 2000 to ozone destruction inside the vortex and successive transport of these air masses to mid-latitudes. Further, the impact of denitrification, PSC-occurrence and anthropogenic chlorine loading on future stratospheric ozone is determined by applying various scenarios. Lower stratospheric temperatures and denitrification were found to play the most important role in the future evolution of polar ozone depletion

Total Synthesis and Characterization of 7-Hypoquinuclidonium Tetrafluoroborate and 7-Hypoquinuclidone BF_3 Complex

Derivatives of the fully twisted bicyclic amide 7-hypoquinuclidone are synthesized using a Schmidt–Aubé reaction. Their structures were unambiguously confirmed by X-ray diffraction analysis and extensive spectroscopic characterization. Furthermore, the stability and chemical reactivity of these anti-Bredt amides are investigated. 7-Hypoquinuclidonium tetrafluoroborate is shown to decompose to a unique nitrogen bound amide–BF_3 complex of 7-hypoquinuclidone under anhydrous conditions and to react instantaneously with water making it one of the most reactive amides known to date

Mapping the impact of SLM - the WOCAT - DESIRE experience

ABSTRACT Since 1992, the World Overview of Conservation Approaches and Technologies (WOCAT) initiative has developed a standardized method for documentation of Sustainable Land Management (SLM) practices. The resulting on-line database currently counts over 450 technologies and over 350 approaches (implementation strategies) from around 50 countries. WOCAT also developed a tool to map land degradation and conservation. This method complements the information provided by the individual case studies on technologies and approaches. It evaluates what land degradation is occurring where and what is done about. The challenge is now to implement SLM practices that address environmental, economic and social concerns, i.e. decreasing degradation and improving ecosystems, while enhancing agricultural productivity and the livelihoods of land users. Research to show and quantify these impacts of SLM practices and on implementation strategies is undertaken in projects like DESIRE, in which the WOCAT methods and tools were used and further developed, from which results are presented herewith. These showed that land degradation mainly occurred as water erosion on cultivated and mixed land use. Degradation was increasing in most sites, primarily caused by inappropriate soil management. Indirectly, population pressure, insecure land tenure, and poverty appeared to be major causes of degradation. Land degradation negatively affected ecosystem services for almost all degraded areas. High negative impacts were observed regarding regulation of ecosystem services indicating that these require particular attention when developing and implementing remediation strategies. SLM measures appeared most effective on cultivated land, but positive impacts were also recorded for relatively large areas of forest and grazing land. Combinations of SLM measures appeared to perform better than single measures. Overall, there appears to be scope for improving SLM contributions to ecosystem services in cultivated land

Search-Based Motion Planning for Performance Autonomous Driving

Driving on the limits of vehicle dynamics requires predictive planning of future vehicle states. In this work, a search-based motion planning is used to generate suitable reference trajectories of dynamic vehicle states with the goal to achieve the minimum lap time on slippery roads. The search-based approach enables to explicitly consider a nonlinear vehicle dynamics model as well as constraints on states and inputs so that even challenging scenarios can be achieved in a safe and optimal way. The algorithm performance is evaluated in simulated driving on a track with segments of different curvatures.Comment: Accepted to IAVSD 201

On the fourth-order accurate compact ADI scheme for solving the unsteady Nonlinear Coupled Burgers' Equations

The two-dimensional unsteady coupled Burgers' equations with moderate to severe gradients, are solved numerically using higher-order accurate finite difference schemes; namely the fourth-order accurate compact ADI scheme, and the fourth-order accurate Du Fort Frankel scheme. The question of numerical stability and convergence are presented. Comparisons are made between the present schemes in terms of accuracy and computational efficiency for solving problems with severe internal and boundary gradients. The present study shows that the fourth-order compact ADI scheme is stable and efficient

PSSA-2, a Membrane-Spanning Phosphoprotein of Trypanosoma brucei, Is Required for Efficient Maturation of Infection

The coat of Trypanosoma brucei consists mainly of glycosylphosphatidylinositol-anchored proteins that are present in several million copies and are characteristic of defined stages of the life cycle. While these major components of the coats of bloodstream forms and procyclic (insect midgut) forms are well characterised, very little is known about less abundant stage-regulated surface proteins and their roles in infection and transmission. By creating epitope-tagged versions of procyclic-specific surface antigen 2 (PSSA-2) we demonstrated that it is a membrane-spanning protein that is expressed by several different life cycle stages in tsetse flies, but not by parasites in the mammalian bloodstream. In common with other membrane-spanning proteins in T. brucei, PSSA-2 requires its cytoplasmic domain in order to exit the endoplasmic reticulum. Correct localisation of PSSA-2 requires phosphorylation of a cytoplasmic threonine residue (T305), a modification that depends on the presence of TbMAPK4. Mutation of T305 to alanine (T305A) has no effect on the localisation of the protein in cells that express wild type PSSA-2. In contrast, this protein is largely intracellular when expressed in a null mutant background. A variant with a T305D mutation gives strong surface expression in both the wild type and null mutant, but slows growth of the cells, suggesting that it may function as a dominant negative mutant. The PSSA-2 null mutant exhibits no perceptible phenotype in culture and is fully competent at establishing midgut infections in tsetse, but is defective in colonising the salivary glands and the production of infectious metacyclic forms. Given the protein's structure and the effects of mutation of T305 on proliferation and localisation, we postulate that PSSA-2 might sense and transmit signals that contribute to the parasite's decision to divide, differentiate or migrate