Bayan Obo ore deposit is the largest rare-earth element（REE） resource,and the second largest niobium（Nb） resource in the world.Due to the complicated element/mineral compositions and involving ...several geological events,the REE enrichment mechanism and genesis of this giant deposit still remains intense debated.The deposit is hosted in the massive dolomite,and nearly one hundred carbonatite dykes occur in the vicinity of the deposit.The carbonatite dykes can be divided into three types from early to late：dolomite,co-existing dolomite-calcite and calcite type,corresponding to different evolutionary stages of carbonatite magmatism based on the REE and trace element data.The latter always has higher REE content.The origin of the ore-hosting dolomite at Bayan Obo has been addressed in various models,ranging from a normal sedimentary carbonate rocks to volcano-sedimentary sequence,and a large carbonatitic intrusion.More geochemical evidences show that the coarse-grained dolomite represents a Mesoproterozoic carbonatite pluton and the fine-grained dolomite resulted from the extensive REE mineralization and modification of the coarse-grained variety.The ore bodies,distributed along an E-W striking belt,occur as large lenses and underwent more intense fluoritization and fenitization.The first episode mineralization is characterized by disseminated mineralization in the dolomite.The second or main-episode is banded and/or massive mineralization,cut by the third episode consisting of aegirinerich veins.Various dating methods gave different mineralization ages at Bayan Obo,resulting in long and hot debates.Compilation of available data suggests that the mineralization is rather variable with two peaks at～1400 and 440 Ma.The early mineralization peak closes in time to the intrusion of the carbonatite dykes.A significant thermal event at ca.440 Ma resulted in the formation of late-stage veins with coarse crystals of REE minerals.Fluids involving in the REE-Nb-Fe mineralization at Bayan Obo might be REE-F-C02-NaCI-H20 system.The presence of REE-carbonates as an abundant solid in the ores shows that the original ore-forming fluids are very rich in REE,and therefore,have the potential to produce economic REE ores at Bayan Obo.the Bayan Obo deposit is a product of mantle-derived carbonatitic magmatism at ca.1400 Ma,which was likely related to the breakup of Columbia.Some remobilization of REE occurred due to subduction of the Palaeo-Asian oceanic plate during the Silurian,forming weak vein-like mineralization.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this paper, we focus on heterogeneous features learning for RGB-D activity recognition. We find that features from different channels (RGB, depth) could share some similar hidden structures, and ...then propose a joint learning model to simultaneously explore the shared and feature-specific components as an instance of heterogeneous multi-task learning. The proposed model formed in a unified framework is capable of: 1) jointly mining a set of subspaces with the same dimensionality to exploit latent shared features across different feature channels, 2) meanwhile, quantifying the shared and feature-specific components of features in the subspaces, and 3) transferring feature-specific intermediate transforms (i-transforms) for learning fusion of heterogeneous features across datasets. To efficiently train the joint model, a three-step iterative optimization algorithm is proposed, followed by a simple inference model. Extensive experimental results on four activity datasets have demonstrated the efficacy of the proposed method. Anew RGB-D activity dataset focusing on human-object interaction is further contributed, which presents more challenges for RGB-D activity benchmarking.
The Zhuangzi Au deposit in the world-class Jiaodong gold province hosts visible natural gold, and pyrite as the main ore mineral, making it an excellent subject for deciphering the complex ...hydrothermal processes and mechanisms of gold precipitation. Three types of zoned pyrite crystals were distinguished based on textural and geochemical results from EPMA, SIMS sulfur isotopic analyses and NanoSIMS mapping. Py0 has irregular shapes and abundant silicate inclusions and was contemporaneous with the earliest pyrite–sericite–quartz alteration. It has low concentrations of As (0–0.3 wt.%), Au and Cu. Py1 precipitated with stage I mineralization shows oscillatory zoning with the bright bands having high As (0.4–3.9 wt.%), Au and Cu contents, whereas the dark bands have low contents of As (0–0.4 wt.%), Au and Cu. The oscillatory zoning represents pressure fluctuations and repeated local fluid phase separation around the pyrite crystal. The concentration of invisible gold in Py1 is directly proportional to the arsenic concentration. Py1 is partially replaced by Py2 which occurs with arsenopyrite, chalcopyrite and native gold in stage II. The replacement was likely the result of pseudomorphic dissolution–reprecipitation triggered by a new pulse of Au-rich hydrothermal fluids. The δ
34
S values for the three types of pyrite are broadly similar ranging from + 7.1 to + 8.8‰, suggesting a common sulfur source. Fluid inclusion microthermometry suggests that extensive phase separation was responsible for the gold deposition during stage II mineralization. Uranium–Pb dating of monazite constrains the age of mineralization to ca. 119 Ma coincident with a short compressional event around 120 Ma linked to an abrupt change in the drift direction of the subducting Pacific plate.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
4.
Early Action Prediction by Soft Regression Hu, Jian-Fang; Zheng, Wei-Shi; Ma, Lianyang ...
IEEE transactions on pattern analysis and machine intelligence,
11/2019, Volume:
41, Issue:
11
Journal Article
Peer reviewed
Open access
We propose a novel approach for predicting on-going action with the assistance of a low-cost depth camera. Our approach introduces a soft regression-based early prediction framework. In this ...framework, we estimate soft labels for the subsequences at different progress levels, jointly learned with an action predictor. Our formulation of soft regression framework 1) overcomes a usual assumption in existing early action prediction systems that the progress level of on-going sequence is given in the testing stage; and 2) presents a theoretical framework to better resolve the ambiguity and uncertainty of subsequences at early performing stage. The proposed soft regression framework is further enhanced in order to take the relationships among subsequences and the discrepancy of soft labels over different classes into consideration, so that a Multiple Soft labels Recurrent Neural Network (MSRNN) is finally developed. For real-time performance, we also introduce a new RGB-D feature called "local accumulative frame feature (LAFF)", which can be computed efficiently by constructing an integral feature map. Our experiments on three RGB-D benchmark datasets and an unconstrained RGB action set demonstrate that the proposed regression-based early action prediction model outperforms existing models significantly and also show that the early action prediction on RGB-D sequence is more accurate than that on RGB channel.
Sports tourism can stimulate the development of related industries, such as tourism, recreation, service, business industry, retail industry and so on. Therefore, it has been attracting attention ...from all over the world. With the Beijing Olympic Games, Guangzhou Asian Games and Shanghai World Expo held one after another, China has paid some attention to the development of Sports tourism. International convention and exhibition centers have been built in Shanghai, Shenzhen, and other first-tier cities in China, and activities are carried out regularly to attract domestic and foreign tourists. sports tourism has become a hot topic in domestic tourism development, but due to the late start of China's sports industry, relevant research is also lagging behind. In order to better develop China's Sports tourism, it is necessary to draw on the advanced experience of foreign countries in developing Sports tourism, construct a Sports tourism business model with Chinese characteristics and establish an MICE tourism business system in line with China's national conditions. Therefore, the core idea of this paper is to build a user-oriented personalized tourism information recommendation model on the existing big data of Sports tourism, combine data mining knowledge and recommendation system algorithm, and analyze the development power mechanism and management mode of Sports tourism. The research concludes that Sports tourism should be closely integrated with Sports industry, give full play to its industry advantages to serve Sports industry, promote Sports tourism at a deeper level and form an interactive win-win effect.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Summary
People can make pointing gestures and tracing actions with the index finger with little or no conscious effort. From the perspective of cognitive load theory, such “biologically primary” ...gestures and actions might help people learn “biologically secondary” concepts and skills requiring extended cognitive effort, such as reading, science, or mathematics. Studies on tracing or tracing and pointing have yielded mixed findings regarding hypothesized effects on intrinsic and extraneous cognitive load. The present study investigated whether computer‐based instructions to trace elements of worked examples on angle relationships would affect school students' (N = 106) self‐reports of intrinsic and extraneous cognitive load, as well as problem‐solving transfer test performance. The tracing effect on transfer posttests seen in prior studies was replicated, but cognitive load hypotheses were not supported. Implications for educational practice and future research are discussed.
Full text
Available for:
DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
The Jiaodong Peninsula in the eastern North China Craton (NCC) hosts some of the world-class gold deposits. Among these, the Shangzhuang gold deposit represents a typical fault-zone hosted ...disseminated- and stockwork-style gold mineralization. The mineralization is characterized by intense hydrothermal alteration halos in the wallrocks with the mineralized veins intruding into altered wallrocks. Zircon U-Pb isotope dating constrains the timing of emplacement of the Guojialing granodiorite as 130±1Ma. Five molybdenite samples from the main mineralization stage veins yielded a well-fitted isochron age of 126±2Ma (MSWD=1.3), marking the timing of gold mineralization. Four types of fluid inclusions are identified at Shangzhuang, and their petrographic and microthermometric features suggest fluid immiscibility followed by fluid mixing. This inference is also supported by oxygen and hydrogen isotopic data of quartz veins from stage III. The measured δ18O values of quartz are +12.3 to +13.7‰ for stage II and +11.7 to +12.0‰ for stage III, with calculated δ18Ofluid values for stage II ranging from +5.9 to +7.3‰ and for stage III from +3.4 to +3.7‰. δD values for stage II and III quartz range from −65.3 to −75.2‰ and −70.6 to −74.7‰, respectively. The data suggest that the ore-forming fluids were initially derived from magmatic sources, followed by mixing with meteoric water. SIMS in-situ sulfur isotope analyses of two types of pyrite (Py I and Py II) from different mineralization stages show different sulfur isotope features. The δ34S values for Py I (+10.2 to +11.3‰, mean=+10.8‰, n=25) are higher than those of the later mostly gold-related Py II (+4.1 to +6.8‰, mean=+5.4‰, n=27). The higher δ34S values of Py I are correlated to degassing of mantle wedge metasomatized by the slab fluids. The relatively lower δ34S values of Py II might suggest increasing of fO2 through fluid mixing between ore-forming fluids and meteoric water.
The temporal, spatial and tectonic relations between the giant gold mineralization and destruction of the NCC suggest a genetic linkage. The gold mineralization between 126 and 117Ma at Jiaodong was probably initiated at the peak of decratonization (ca. 125Ma) of the eastern NCC. Phanerozoic craton margin orogeny also played a critical role in the generation of the early Cretaceous giant gold deposits in the eastern NCC. Integrated geological characteristics, mineralization features, metallogenic age, sources of ore-forming fluids and sulfur, and tectonic settings favor a decratonic gold mineralization model for the Shangzhuang gold deposit. The geodynamic scenario proposed for the early Cretaceous giant gold mineralization event in the eastern NCC includes the paleo-West Pacific plate subduction, asthenospheric upwelling, multiple subduction-collision processes along the margins.
Display omitted
•Re-Os dating of gold-related molybdenite implies timing of gold mineralization is 126Ma.•Fluid immiscibility occurred in stage I, II; fluid mixing happened in stage III.•SIMS S isotopes reveal transformation of mineralization condition.•A decratonic gold mineralization model is proposed for Shangzhuang gold deposit.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The late Mesozoic granitoids widely distributed in the northwestern Jiaodong Terrane are important markers of cratonic destruction and lithospheric thinning of the eastern North China Craton (NCC). ...Here we investigate the Late Jurassic Linglong and Luanjiahe granites and report zircon U–Pb emplacement ages of 157–159Ma. These rocks also contain abundant late Archean, Paleoproterozoic, Neoproterozoic, early Paleozoic and Triassic inherited zircons, suggesting the involvement of continental crustal materials from both the NCC and Yangtze Craton in magma tectonics. The rocks investigated in this study show high Na2O+K2O and low MgO and are peraluminous, with enrichment in LREEs and LILEs (Rb, Ba, U, and Sr) and depletion in HFSEs (Nb, Ta, P, and Ti). They also display low εHf(t) values and high Sr/Y ratios, comparable to adakitic rocks, suggesting that the Linglong and Luanjiahe granitoids formed under relatively high pressure conditions and were likely derived from the partial melting of the thickened lower crust of the NCC. The Guojialing granodiorites were emplaced in the early Cretaceous (129Ma), and also contain abundant late Archean and Paleoproterozoic inherited zircons. The rocks possess high CaO, TFe2O3 and MgO, and are metaluminous, with enrichment in LREEs and LILEs and depletion in HFSEs. They are also characterized by high Sr/Y ratios, and have higher εNd(t) and εHf(t) values than the Late Jurassic granitoids, suggesting the involvement of mantle components in the magmatic source. We correlate the magma tectonics with the processes accompanying the subduction of the Pacific Plate beneath the NCC and the associated asthenospheric upwelling.
► Late Jurassic granites were derived from partial melting of thickened lower crust. ► Early Cretaceous granodiorites were triggered by subduction of the Pacific Plate. ► Zircon ages suggest the involvement of both NCC and Yangtze Craton in magma tectonics. ► They provide marker for cratonic destruction and lithospheric thinning of the NCC.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Gradient boosting regression and random forest are combined to analyse net ecosystem carbon exchange.•The model considers 22 environmental variables, more than other similar works.•The extremums are ...employed to analyse the corresponding variables’ importance.
Carbon balance is essential to keep ecosystems sustainable and healthy. Net ecosystem carbon exchange (NEE), which is affected by a bunch of meteorological variables to different extent, helps to gauge the balance of the carbon cycle between biological organisms and atmosphere. In this study, the NEE data is collected from two flux measuring sites. Gradient boosting regression algorithm is employed to predict NEE based on the meteorology and flux data from site UK-Gri. During the training process, KFold cross-validation algorithm is implemented to avoid overfitting, and random forest algorithm is implemented to identify the important variables influencing NEE mostly. The four most important variables are found to be global radiation, photosynthetic active radiation, minimum soil temperature, and latent heat. The regression model was compared with three state-of-the-art prediction models: support vector machine, stochastic gradient descent, and bayesian ridge to verify its performance. The experimental results show that this regression model outperforms the other three models, and gives higher value of R-squared, lower values of mean absolute error and root mean squared error. To verify the regression model’s generalization ability, the data from the second flux site, NL-Loo, was employed, and the hybrid data of the two sites was used. The results show that this model performs well on the hybrid data, too. In practical terms, the gradient boosting regression model provides many tunable hypterparameters and loss functions, which make it more flexible and accurate compared to the other three models. This study has conclusively demonstrated for the first time that the combination of gradient boosting regression and random forest models should be considered as valuable tools to make effective prediction for NEE and acquire reliable important variables influencing NEE mostly. The methodologies could be useful in the research fields of ecosystem stability evaluation, environmental restoration, trend analysis of climate change, and global warming monitoring.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The asymmetric 4+1 annulation of activated α,β-unsaturated ketones with MBH carbonates catalyzed by bifunctional thiourea-phosphine catalysts derived from an axially chiral binaphthyl scaffold has ...been developed, giving spirooxindoles with two adjacent quaternary stereocenters in good yields with high enantioselectivities and moderate diastereoselectivities under mild conditions.
PDF
