Spillways Scheduling for Flood Control of Three Gorges Reservoir Using Mixed Integer Linear Programming Model

This study proposes a mixed integer linear programming (MILP) model to optimize the spillways scheduling for reservoir flood control. Unlike the conventional reservoir operation model, the proposed MILP model specifies the spillways status (including the number of spillways to be open and the degree of the spillway opened) instead of reservoir release, since the release is actually controlled by using the spillway. The piecewise linear approximation is used to formulate the relationship between the reservoir storage and water release for a spillway, which should be open/closed with a status depicted by a binary variable. The control order and symmetry rules of spillways are described and incorporated into the constraints for meeting the practical demand. Thus, a MILP model is set up to minimize the maximum reservoir storage. The General Algebraic Modeling System (GAMS) and IBM ILOG CPLEX Optimization Studio (CPLEX) software are used to find the optimal solution for the proposed MILP model. The China’s Three Gorges Reservoir, whose spillways are of five types with the total number of 80, is selected as the case study. It is shown that the proposed model decreases the flood risk compared with the conventional operation and makes the operation more practical by specifying the spillways status directly

Biological Nitrogen Fixation and Nitrogen Accumulation in Peatlands

International audiencePeatlands cover about 3% of the Earth's surface and are regarded as a vital carbon (C) pool and sink. The formation of peatland is supported by continuously supplied nitrogen (N) but the sources of this N remain unclear. Here, we first review N stocks and the rate they accumulate in peatlands, then we present the sources of N, especially through biological nitrogen fixation (BNF). We found that global peatlands store 5.9-25.9 Gt N. In the past millennia, northern peatlands have a lower N accumulated rate than tropical undisturbed peatlands. BNF rate is approximately 1.9 ± 2.7 g m −2 yr −1 in northern peatlands, higher than the rate of N deposition, 0.5 ± 0.4 g m −2 yr −1. For tropical peatlands, BNF observation has hardly been reported yet and needs further investigation. This review provides a broad picture of peatland N cycling and suggests that there are large uncertainties, due to limited observations of BNF and N fluxes by inflow and outflow runoff. Therefore, we call for more efforts contributing to field observations and modelling of the N budget in peatlands

Male Occult Breast Cancer First Manifesting as a Supraclavicular Lymph Node Metastasis: A Case Report

Male occult breast cancer has a lower incidence, later clinical stage at detection, poorer differentiation, worse prognosis, and metastasizes earlier than breast cancer in females due to its rarity and a lack of public awareness. We report a 64 year old male patient presenting with palpable masses in his left cervical region, in whom imaging was unremarkable, except for slightly enlarged axillary lymph nodes without increased metabolic activity and an area of high metabolic activity in the left supraclavicular fossa. The purpose of this case report is to present the imaging, pathological features, and our treatment for male OBC

Wetlands Cool Land Surface Temperature in Tropical Regions but Warm in Boreal Regions

Wetlands play a critical role in global hydrological and biogeochemical cycles. Regulating the regional climate is one of the most important ecosystem services of natural wetlands. However, the impact of wetlands on local temperature on the global scale and the attribution is still unclear. This study utilizes the satellite-based products (land surface temperature (LST), albedo, and evapotranspiration (ET)) to evaluate the difference in LST between wetlands and their adjacent landcover types and the possible drivers. Here we show that on average for the whole year, wetlands have a cooling effect in tropical regions, but have a warming effect in boreal regions. The impacts of wetlands on LST show great seasonality in the boreal regions; i.e., the wetlands have a warming effect in winter but a cooling effect in summer. The difference in albedo and ET between wetlands and the other landcover types only interprets 30% of temporal variation of the difference in LST. Due to the large water storage in wetlands, the ground heat flux (G) may interpret the rest of the impact, absorbing energy in summer and releasing energy in winter in wetlands, which has often been neglected in previous studies. Our results indicate that it is critical to comprehensively consider the effects of wetland restoration in different regions to realize potential climatic benefits in the future

Learning Adaptive Spatial Regularization and Temporal-Aware Correlation Filters for Visual Object Tracking

Recently, discriminative correlation filters (DCF) based trackers have gained much attention and obtained remarkable achievements for their high efficiency and outstanding performance. However, undesirable boundary effects occur when the DCF-based trackers suffer from challenging situations, such as occlusion, background clutters, fast motion, and so on. To address these problems, this work proposes a novel adaptive spatial regularization and temporal-aware correlation filters (ASTCF) model to deal with the boundary effects which occur in the correlation filters tracking. Firstly, our ASTCF model learns a more robust correlation filter template by introducing spatial regularization and temporal-aware components into the objective function. The adaptive spatial regularization provides a more robust appearance model to handle the large appearance changes at different times; meanwhile, the temporal-aware constraint can enhance the time continuity and consistency of this model. They make correlation filters model more discriminating, and also reduce the influence of the boundary effects during the tracking process. Secondly, the objective function can be transformed into three sub-problems with closed-form solutions and effectively solved via the alternating direction method of multipliers (ADMM). Finally, we compare our tracker with some representative methods and evaluate using three different benchmarks, including OTB2015, VOT2018 and LaSOT datasets, where the experimental results demonstrate the superiority of our tracker on most of the performance criteria compared with the existing trackers

Learning Adaptive Spatial Regularization and Temporal-Aware Correlation Filters for Visual Object Tracking

Recently, discriminative correlation filters (DCF) based trackers have gained much attention and obtained remarkable achievements for their high efficiency and outstanding performance. However, undesirable boundary effects occur when the DCF-based trackers suffer from challenging situations, such as occlusion, background clutters, fast motion, and so on. To address these problems, this work proposes a novel adaptive spatial regularization and temporal-aware correlation filters (ASTCF) model to deal with the boundary effects which occur in the correlation filters tracking. Firstly, our ASTCF model learns a more robust correlation filter template by introducing spatial regularization and temporal-aware components into the objective function. The adaptive spatial regularization provides a more robust appearance model to handle the large appearance changes at different times; meanwhile, the temporal-aware constraint can enhance the time continuity and consistency of this model. They make correlation filters model more discriminating, and also reduce the influence of the boundary effects during the tracking process. Secondly, the objective function can be transformed into three sub-problems with closed-form solutions and effectively solved via the alternating direction method of multipliers (ADMM). Finally, we compare our tracker with some representative methods and evaluate using three different benchmarks, including OTB2015, VOT2018 and LaSOT datasets, where the experimental results demonstrate the superiority of our tracker on most of the performance criteria compared with the existing trackers

Binding of RhoA by the C2 domain of E3 ligase Smurf1 is essential for Smurf1-regulated RhoA ubiquitination and cell protrusive activity

AbstractSmurf1-mediated RhoA ubiquitination and degradation plays key roles in regulation of cell polarity and protrusive activity. However, how Smurf1 recognizes RhoA is still not clear. Here we report that the C2 domain of Smurf1 is necessary and sufficient for binding RhoA, and therefore is crucial for targeting RhoA for ubiquitination. In contrast, the C2 domain is dispensable for Smurf1-mediated ubiquitination of Smad1. Consistent with its biochemical specificity, the C2 domain is essential for Smurf1-regulated protrusion formation but not BMP signaling. Therefore, our study reveals the mechanism of the C2 domain of Smurf1 in substrate selection.Structured summary of protein interactionsSMURF1physically interactswithSmad1 by pull down(View interaction)SMURF1physically interactswithRhoA by pull down(View interaction)SMURF1physically interactswithSmad1 by anti tag coimmunoprecipitation(View interaction)SMURF1physically interactswithRhoA by anti tag coimmunoprecipitation(View interaction

Molecular Understanding of Electrochemical–Mechanical Responses in Carbon-Coated Silicon Nanotubes during Lithiation

Carbon-coated silicon nanotube (SiNT@CNT) anodes show tremendous potential in high-performance lithium ion batteries (LIBs). Unfortunately, to realize the commercial application, it is still required to further optimize the structural design for better durability and safety. Here, the electrochemical and mechanical evolution in lithiated SiNT@CNT nanohybrids are investigated using large-scale atomistic simulations. More importantly, the lithiation responses of SiNW@CNT nanohybrids are also investigated in the same simulation conditions as references. The simulations quantitatively reveal that the inner hole of the SiNT alleviates the compressive stress concentration between a-LixSi and C phases, resulting in the SiNT@CNT having a higher Li capacity and faster lithiation rate than SiNW@CNT. The contact mode significantly regulates the stress distribution at the inner hole surface, further affecting the morphological evolution and structural stability. The inner hole of bare SiNT shows good structural stability due to no stress concentration, while that of concentric SiNT@CNT undergoes dramatic shrinkage due to compressive stress concentration, and that of eccentric SiNT@CNT is deformed due to the mismatch of stress distribution. These findings not only enrich the atomic understanding of the electrochemical–mechanical coupled mechanism in lithiated SiNT@CNT nanohybrids but also provide feasible solutions to optimize the charging strategy and tune the nanostructure of SiNT-based electrode materials