Estimate of Heavy Metals in Soil Using Combined Geochemistry and Field Spectroscopy in Miyi Mining Area

Heavy metal-contaminated soil and water is a major environmental issue in the mining areas. However, as the heavy metals migrate frequently, the traditional method of estimating the soil’s heavy metal content by field sampling and laboratory chemical analysis followed by interpolation is time-consuming and expensive. This chapter intends to use field hyperspectra to estimate the heavy metals in the soil in Bai-ma, De-sheng and YuanBaoshan mining areas, Miyi County, Sichuan Province. By analyzing the spectra of soil, the spectral features derived from the spectra of the soils can be found to build the models between these features and the contents of Mn and Co in the soil by using the linear regression method. The spectral features of Mn are 2142 and 2296 nm. The spectral features of Co are 1918, 1922 and 2205 nm. With these feature spectra, the best models to estimate the heavy metals in the study area can be built according to the maximal determination coefficients (R2). The determination coefficients (R2) of the models of retrieving Mn and Co in the soil are 0.645 and 0.8, respectively. The model significant indexes of Mn and Co are 2.04507E-05 and 7.73E-06. These results show that it is feasible to predict contaminated heavy metals in the soils during mining activities for soil remediation and ecological restoration by using the rapid and cost-effective field spectroscopy

The Devil is in the Details: A Deep Dive into the Rabbit Hole of Data Filtering

The quality of pre-training data plays a critical role in the performance of foundation models. Popular foundation models often design their own recipe for data filtering, which makes it hard to analyze and compare different data filtering approaches. DataComp is a new benchmark dedicated to evaluating different methods for data filtering. This paper describes our learning and solution when participating in the DataComp challenge. Our filtering strategy includes three stages: single-modality filtering, cross-modality filtering, and data distribution alignment. We integrate existing methods and propose new solutions, such as computing CLIP score on horizontally flipped images to mitigate the interference of scene text, using vision and language models to retrieve training samples for target downstream tasks, rebalancing the data distribution to improve the efficiency of allocating the computational budget, etc. We slice and dice our design choices, provide in-depth analysis, and discuss open questions. Our approach outperforms the best method from the DataComp paper by over 4% on the average performance of 38 tasks and by over 2% on ImageNet.Comment: 12 pages, 10 figure

Why Is Prompt Tuning for Vision-Language Models Robust to Noisy Labels?

Vision-language models such as CLIP learn a generic text-image embedding from large-scale training data. A vision-language model can be adapted to a new classification task through few-shot prompt tuning. We find that such a prompt tuning process is highly robust to label noises. This intrigues us to study the key reasons contributing to the robustness of the prompt tuning paradigm. We conducted extensive experiments to explore this property and find the key factors are: 1) the fixed classname tokens provide a strong regularization to the optimization of the model, reducing gradients induced by the noisy samples; 2) the powerful pre-trained image-text embedding that is learned from diverse and generic web data provides strong prior knowledge for image classification. Further, we demonstrate that noisy zero-shot predictions from CLIP can be used to tune its own prompt, significantly enhancing prediction accuracy in the unsupervised setting. The code is available at https://github.com/CEWu/PTNL.Comment: Accepted by ICCV202

Spatial scale effect of surface routing and its parameter upscaling for urban flood simulation using a grid‐based model

Urban catchments are characterized by a wide variety of complex juxtapositions and surface compositions that are linked to multiple overland flow paths. Their extremely high spatial heterogeneity leads to great sensitivity of hydrologic simulation to the scale variation of calculation units. Although extensive efforts have been made for investigating the scale effects and indicate its significance, less is understood of how routing features vary with spatial scales and further how the variation of routing features influences the hydrological response. In this paper, a grid-based distributed urban hydrological model is applied to study spatial scale effects ranging from 10 to 250 m. Two parameters are proposed to quantitatively depict the routing features of overland flow specified for impervious and pervious areas. The results show that routing features are quite sensitive to spatial resolution. Large differences among simulations exist in the infiltration amounts attributed to the combined effects of the two routing parameters, which leads to opposite effects for both total flow volume and peak flow for various rainfall events. The relationship of the key model parameters at different spatial resolutions can be explicitly expressed by corresponding routing features. With this relationship, parameters transfer among different spatial scales can be realized to obtain consistent simulation results. This study further revealed the quantitative relationship between spatial scales, routing features and the hydrologic processes, and enabled accurate and efficient simulations required by real time flooding forecasting and land-atmosphere coupling, while fully taking the advantages of detailed surface information. Plain Language Summary Given the inherent complex underlying surface compositions and overland flow paths in urban areas, underlying high spatial resolution surface data eventually become necessary. Unfortunately, high resolution modelling in urban catchment is still challenging in terms of computational restricts, proper setting up of parameters etc., due to the high spatial heterogeneity. Practical simulation requirements often limit the use of high resolution models, as in the case of real time prediction of urban flooding, the coupling of land-atmosphere processes. Therefore, it is necessary to investigate the scale effects and its mechanism, and then to explore an accommodation approach to enable precise flooding prediction with a coarse model. For grid-based and distributed hydrologic models, the mosaic method can basically eliminate the scale effects on the runoff generation process. However, the scale effects on overland flow routing remain insufficiently understood, and to help understand the scale effects, simulations were performed under five different resolutions, ranging from 10 m to 250 m, for various rainfall events. Two physical parameters are introduced to quantify the scale effects on routing features. Three variables are concurrently calculated to assess the effects on modeling outputs. The results indicate that routing features are sensitive to changes in spatial resolution, which results in opposite effects on simulation results under different rainfall conditions. In conclusion, an accommodation approach is proposed based on the affecting mechanism

(E)-2-Acetyl­pyrazine 4-nitro­phenyl­hydrazone

In the title compound, C12H11N5O2, the mol­ecule adopts an E configuration, with the benzene and pyrazine rings located on opposite sides of the N=C double bond. The face-to-face separations of 3.413 (14) and 3.430 (8) Å, respectively between parallel benzene rings and between pyrazine rings indicate the existence of π–π stacking between adjacent mol­ecules. The crystal structure also contains N—H⋯N and C—H⋯O hydrogen bonding

Comparative study of earthquake-related and non-earthquake-related head traumas using multidetector computed tomography

OBJECTIVE: The features of earthquake-related head injuries may be different from those of injuries obtained in daily life because of differences in circumstances. We aim to compare the features of head traumas caused by the Sichuan earthquake with those of other common head traumas using multidetector computed tomography. METHODS: In total, 221 patients with earthquake-related head traumas (the earthquake group) and 221 patients with other common head traumas (the non-earthquake group) were enrolled in our study, and their computed tomographic findings were compared. We focused the differences between fractures and intracranial injuries and the relationships between extracranial and intracranial injuries. RESULTS: More earthquake-related cases had only extracranial soft tissue injuries (50.7% vs. 26.2%, RR=1.9), and fewer cases had intracranial injuries (17.2% vs. 50.7%, RR = 0.3) compared with the non-earthquake group. For patients with fractures and intracranial injuries, there were fewer cases with craniocerebral injuries in the earthquake group (60.6% vs. 77.9%, RR = 0.8), and the earthquake-injured patients had fewer fractures and intracranial injuries overall (1.5 + 0.9 vs. 2.5 +1.8; 1.3 + 0.5 vs. 2.1 + 1.1). Compared with the non-earthquake group, the incidences of soft tissue injuries and cranial fractures combined with intracranial injuries in the earthquake group were significantly lower (9.8% vs. 43.7%, RR = 0.2; 35.1% vs. 82.2%, RR = 0.4). CONCLUSION: As depicted with computed tomography, the severity of earthquake-related head traumas in survivors was milder, and isolated extracranial injuries were more common in earthquake-related head traumas than in non-earthquake-related injuries, which may have been the result of different injury causes, mechanisms and settings

Construction of α,α‐disubstituted α‐Amino Acid Derivatives via aza‐Morita‐Baylis‐Hillman Reactions of 2‐Aminoacrylates with Activated Olefins

A useful and convenient strategy for the synthesis of α,α‐disubstituted α‐amino acid (α‐AA) derivatives via aza‐Morita‐Baylis‐Hillman reaction of 2‐aminoacrylates with activated olefins has been developed. A variety of α‐AA derivatives containing an α‐amino tertiary center were synthesized in good to excellent yields. The kinetic profiles and calculated methyl anion affinity (MAA) values were employed to rationalize the reactivities of different Michael acceptors used in the reaction

Origin of two types of rhyolites in the Tarim Large Igneous Province: Consequences of incubation and melting of a mantle plume

The Early Permian Tarim Large Igneous Province (LIP) in northwestern China contains a large area of silicic volcanics (similar to 48,000 km(2)) which are spatially and temporally associated with mafic-ultramafic rocks. In order to understand the behavior of crust above a mantle plume, selected rhyolitic samples are investigated in terms of U-Pb zircon dating, geochemical and isotopic analyses. The Tarim rhyolites have high A/CNK ratios (= molar Al2O3/CaO + Na2O + K2O), Fe#, Ga/Al ratios, concentrations of high field strength elements (HFSEs) such as Zr and Nb, and rare earth elements (REEs), along with high zircon saturation temperatures (872-940 degrees C), typical of aluminous A-type granitoids. Two contrasting rock types have been recognized. The low Nb-Ta type rhyolites are mainly associated with the first phase of the Tarim flood basalt magmatism at similar to 290 Ma. They are characterized by negative Nb-Ta anomalies, low epsilon(Nd)(t) and epsilon(Hf)(t) values, and high Sr-87/Sr-88(t) and delta(18) O-zircon values, consistent with a derivation from continental crustal source. The high Nb-Ta type rhyolites and their plutonic equivalents are associated with the second episode of Tarim magmatism (283-272 Ma). They are characterized by small negative to positive Nb-Ta anomalies, oceanic island basalt (0113)-like trace element ratios, low Sr-87/Sr-88(t) and high epsilon(Nd)(t) and epsilon(Hf)(t) values. These high Nb-Ta rhyolites are best interpreted as hybrid products of crystal fractionation of mafic magmas, coupled with crustal assimilation. The temporal and compositional evolution of the Tarim rhyolites reflects various extents of thermal and mass exchange between mantle-derived basaltic magma and crustal material above a mantle plume. When the plume head rises to the base of the Tarim craton, it first melts enriched components in the lithospheric mantle (similar to 290 Ma), part of which may have ponded near the crust-mantle boundary and induced crustal anatexis leading to the formation of the low Nb-Ta type rhyolites. At similar to 280 Ma, large magma chambers and plumbing systems were formed due to increasing magma supply rate during decompression melting of the mantle plume. This led to the formation of a mafic-ultramafic and felsic association of which the high Nb-Ta type rhyolites are a part. (C) 2014 Elsevier B.V. All right reservedGeochemistry & GeophysicsMineralogySCI(E)[email protected],SI59-7220