Dyke swarms are widespread throughout the Kaapvaal Craton(KC)in South Africa and have been documented in some detail.Up to date,only the^2.9 Ga SE-trending and the^2.7 to^2.66 Ga radiating dyke arrays are
In its cationic,trivalent form,Chromium(Cr)it is a micronutrient,and exhibits low environmental mobility.In hexavalent form,however,it is a human carcinogen and also highly mobile.Climate is a key environmental factor...In its cationic,trivalent form,Chromium(Cr)it is a micronutrient,and exhibits low environmental mobility.In hexavalent form,however,it is a human carcinogen and also highly mobile.Climate is a key environmental factor controlling weathering rates and stability of primary and secondary Cr-bearing minerals.Knowledge of Cr oxidation state and mineral residence is therefore essential to estimating the risk posed by Cr in serpentinites,chromite mine wastes,and soils developed on these parent materials.X-ray absorption spectroscopy(XAS)is currently the best available technique for determination of the relative abundance of Cr(III)and Cr(VI)in situ(that is,without digestion of solid phases).A brief review of relevant XAS studies of is presented below,focusing on studies in tropical climates1,as they will be most relevant to eastern Cuba’s extensively serpentinized ophiolite belt.Cr(III)-bearing spinels are usually the dominant and most refractory Cr host in ultramafic rocks.Previous XAS studies2 indicate that in tropical climates,Cr-spinels weather rapidly to form Cr(III)-bearing secondary Fe(III)(hydr)oxides(goethite,hematite).Manganese(Mn)is also enriched in ultramafic rocks2;as Mn(IV),it can also co-precipitate with Fe(III)(hydr)oxides,or form its own secondary(hydr)oxides.A previous study found up to 20%Cr(VI)in in a tropical,serpentine soil that contained substantial Mn,and a strong correlation between the*amounts of Cr(VI)and Mn(IV)in the soil profile2.Theresults of several XAS studies suggest that a close association of Mn(IV)and Cr(III)in secondary Fe(hydr)oxides is necessary for oxidation of Cr(III)to Cr(VI)via electron transfer reactions with Mn(IV);however,additional XAS studies have shown that organic matter3and Cr-bearing aluminosilicates4 may also be important sources of Cr(III)to the environment under specific conditions.The stability and fate of Cr has not been studied in detail for these two host phase types,to the best of our knowledge.Access to XAS facilities to perform Cr geochemical experiments is limited and will only become more so in the future.We are working to develop and apply(micro)Raman spectroscopy to evaluate Cr oxidation state and mineral residence(in crystalline and amorphous materials).In addition to standard Raman scattering,we are employing resonance Raman(785 nm laser)to enhance signal from Cr(VI)-bearing phases and laser-stimulated photoluminescence to identify Cr(III)associated with Al-rich alteration products展开更多
This study intends to explore the effects of context clues in contextual guessing among 60 first-year non-English majors by using two guessing tests as the research instrument. According to the quantitative analysis o...This study intends to explore the effects of context clues in contextual guessing among 60 first-year non-English majors by using two guessing tests as the research instrument. According to the quantitative analysis of the statistics processed by SPSS （14.0）, it is revealed that （1） context clues affect the outcome of contextual guessing significantly, and （2） English proficiency level plays a significant role in contextual guessing as well. On the basis of the major findings in this research, several pedagogical implications are drawn for college English teachers and students： （1） College English teachers should keep the students better informed of the significance and specific functions of context clues in contextual guessing; （2） College English teachers should encourage the students to guess word meanings from context instead of inhibiting it when there are adequate context clues offered.展开更多
CAS paleontologists have identified a rod-like bone from two early Cretaceous mammals as ossified Meckel's cartilage (OMC). This clears some doubts on the controversial topic of the origin of definitive mannal... CAS paleontologists have identified a rod-like bone from two early Cretaceous mammals as ossified Meckel's cartilage (OMC). This clears some doubts on the controversial topic of the origin of definitive mannalian middle ear (DMME).……展开更多
In recent years,skeleton-based action recognition has made great achievements in Computer Vision.A graph convolutional network(GCN)is effective for action recognition,modelling the human skeleton as a spatio-temporal ...In recent years,skeleton-based action recognition has made great achievements in Computer Vision.A graph convolutional network(GCN)is effective for action recognition,modelling the human skeleton as a spatio-temporal graph.Most GCNs define the graph topology by physical relations of the human joints.However,this predefined graph ignores the spatial relationship between non-adjacent joint pairs in special actions and the behavior dependence between joint pairs,resulting in a low recognition rate for specific actions with implicit correlation between joint pairs.In addition,existing methods ignore the trend correlation between adjacent frames within an action and context clues,leading to erroneous action recognition with similar poses.Therefore,this study proposes a learnable GCN based on behavior dependence,which considers implicit joint correlation by constructing a dynamic learnable graph with extraction of specific behavior dependence of joint pairs.By using the weight relationship between the joint pairs,an adaptive model is constructed.It also designs a self-attention module to obtain their inter-frame topological relationship for exploring the context of actions.Combining the shared topology and the multi-head self-attention map,the module obtains the context-based clue topology to update the dynamic graph convolution,achieving accurate recognition of different actions with similar poses.Detailed experiments on public datasets demonstrate that the proposed method achieves better results and realizes higher quality representation of actions under various evaluation protocols compared to state-of-the-art methods.展开更多
A new museum in Fujian Province shines a spotlight on major discoveries linking the roots of Austronesian people to the Chinese mainland Amajor chapter in the story of humanity’s maritime past has come to light with ...A new museum in Fujian Province shines a spotlight on major discoveries linking the roots of Austronesian people to the Chinese mainland Amajor chapter in the story of humanity’s maritime past has come to light with the recent opening of the Keqiutou Site Branch of the China Archaeology Museum in Pingtan,Fujian Province,on April 9.展开更多
Despite China's economy maintaining its electrifying annual growth, over 10 percent since 2003, the country has somehow successfully kept its inflation rate at relatively low levels. This growth pattern, which con...Despite China's economy maintaining its electrifying annual growth, over 10 percent since 2003, the country has somehow successfully kept its inflation rate at relatively low levels. This growth pattern, which contradicts traditional theories in economics, is challenging many world-renowned economists to speculate on this phenomenon. Fan Gang, Director of the National Economic Research Institute under the China Reform Foundation, and Justin Yifu Lin, Director of the China Center for Economic Research of Peking University, gave their explanations for China's economic miracle at this April's Bo'ao Forum for Asia.展开更多
Scientists are striving to overcome the difficulties in earthquake predictionAt 11:56 a.m. on July 4, those who were indoors in Beijing felt the earth shake like a boat in a mild storm. A few minutes later, they learn...Scientists are striving to overcome the difficulties in earthquake predictionAt 11:56 a.m. on July 4, those who were indoors in Beijing felt the earth shake like a boat in a mild storm. A few minutes later, they learned from radio. TV or the Internet that the epi- center of the magnitude 5.1 earthquake was in Wenan County, Hehei Province, 110展开更多
这是一则科技珍闻。英国的科学家最近发现一种名叫scrub jays(【鸟】灌丛鸦)的鸟具有一直被认为是人类所独有的短暂记忆。对这种鸟的研究的价值 在于:…provides new tools to investigate how space, time and events areremembered in...这是一则科技珍闻。英国的科学家最近发现一种名叫scrub jays(【鸟】灌丛鸦)的鸟具有一直被认为是人类所独有的短暂记忆。对这种鸟的研究的价值 在于:…provides new tools to investigate how space, time and events areremembered in the human brain.这种研究可能为早老年痴呆病患者以及记忆缺失患者带来好消息。展开更多
While reading plays a very important role in English study, many English language learners find it very difficult to fully comprehend some reading materials on account of many unknown words in them. This essay mainly ...While reading plays a very important role in English study, many English language learners find it very difficult to fully comprehend some reading materials on account of many unknown words in them. This essay mainly discusses one technique of guessing meanings of new words according to context clues, thus emphasizing the importance of context.展开更多
Students often have difficulties in reading comprehension because of too many new and unfamiliar words,too little background knowledge and different patterns of thinking among different countries.In this thesis,I reco...Students often have difficulties in reading comprehension because of too many new and unfamiliar words,too little background knowledge and different patterns of thinking among different countries.In this thesis,I recommend applying context clues,synonyms or antonyms,examples,definitions or explanations,cause/effect clues and background clues to make inference when we read texts.展开更多
基金financial support from the PPM Research Group and CIMERA in South Africa
文摘Dyke swarms are widespread throughout the Kaapvaal Craton(KC)in South Africa and have been documented in some detail.Up to date,only the^2.9 Ga SE-trending and the^2.7 to^2.66 Ga radiating dyke arrays are
文摘In its cationic,trivalent form,Chromium(Cr)it is a micronutrient,and exhibits low environmental mobility.In hexavalent form,however,it is a human carcinogen and also highly mobile.Climate is a key environmental factor controlling weathering rates and stability of primary and secondary Cr-bearing minerals.Knowledge of Cr oxidation state and mineral residence is therefore essential to estimating the risk posed by Cr in serpentinites,chromite mine wastes,and soils developed on these parent materials.X-ray absorption spectroscopy(XAS)is currently the best available technique for determination of the relative abundance of Cr(III)and Cr(VI)in situ(that is,without digestion of solid phases).A brief review of relevant XAS studies of is presented below,focusing on studies in tropical climates1,as they will be most relevant to eastern Cuba’s extensively serpentinized ophiolite belt.Cr(III)-bearing spinels are usually the dominant and most refractory Cr host in ultramafic rocks.Previous XAS studies2 indicate that in tropical climates,Cr-spinels weather rapidly to form Cr(III)-bearing secondary Fe(III)(hydr)oxides(goethite,hematite).Manganese(Mn)is also enriched in ultramafic rocks2;as Mn(IV),it can also co-precipitate with Fe(III)(hydr)oxides,or form its own secondary(hydr)oxides.A previous study found up to 20%Cr(VI)in in a tropical,serpentine soil that contained substantial Mn,and a strong correlation between the*amounts of Cr(VI)and Mn(IV)in the soil profile2.Theresults of several XAS studies suggest that a close association of Mn(IV)and Cr(III)in secondary Fe(hydr)oxides is necessary for oxidation of Cr(III)to Cr(VI)via electron transfer reactions with Mn(IV);however,additional XAS studies have shown that organic matter3and Cr-bearing aluminosilicates4 may also be important sources of Cr(III)to the environment under specific conditions.The stability and fate of Cr has not been studied in detail for these two host phase types,to the best of our knowledge.Access to XAS facilities to perform Cr geochemical experiments is limited and will only become more so in the future.We are working to develop and apply(micro)Raman spectroscopy to evaluate Cr oxidation state and mineral residence(in crystalline and amorphous materials).In addition to standard Raman scattering,we are employing resonance Raman(785 nm laser)to enhance signal from Cr(VI)-bearing phases and laser-stimulated photoluminescence to identify Cr(III)associated with Al-rich alteration products
文摘This study intends to explore the effects of context clues in contextual guessing among 60 first-year non-English majors by using two guessing tests as the research instrument. According to the quantitative analysis of the statistics processed by SPSS （14.0）, it is revealed that （1） context clues affect the outcome of contextual guessing significantly, and （2） English proficiency level plays a significant role in contextual guessing as well. On the basis of the major findings in this research, several pedagogical implications are drawn for college English teachers and students： （1） College English teachers should keep the students better informed of the significance and specific functions of context clues in contextual guessing; （2） College English teachers should encourage the students to guess word meanings from context instead of inhibiting it when there are adequate context clues offered.
文摘 CAS paleontologists have identified a rod-like bone from two early Cretaceous mammals as ossified Meckel's cartilage (OMC). This clears some doubts on the controversial topic of the origin of definitive mannalian middle ear (DMME).……
基金supported in part by the 2023 Key Supported Project of the 14th Five Year Plan for Education and Science in Hunan Province with No.ND230795.
文摘In recent years,skeleton-based action recognition has made great achievements in Computer Vision.A graph convolutional network(GCN)is effective for action recognition,modelling the human skeleton as a spatio-temporal graph.Most GCNs define the graph topology by physical relations of the human joints.However,this predefined graph ignores the spatial relationship between non-adjacent joint pairs in special actions and the behavior dependence between joint pairs,resulting in a low recognition rate for specific actions with implicit correlation between joint pairs.In addition,existing methods ignore the trend correlation between adjacent frames within an action and context clues,leading to erroneous action recognition with similar poses.Therefore,this study proposes a learnable GCN based on behavior dependence,which considers implicit joint correlation by constructing a dynamic learnable graph with extraction of specific behavior dependence of joint pairs.By using the weight relationship between the joint pairs,an adaptive model is constructed.It also designs a self-attention module to obtain their inter-frame topological relationship for exploring the context of actions.Combining the shared topology and the multi-head self-attention map,the module obtains the context-based clue topology to update the dynamic graph convolution,achieving accurate recognition of different actions with similar poses.Detailed experiments on public datasets demonstrate that the proposed method achieves better results and realizes higher quality representation of actions under various evaluation protocols compared to state-of-the-art methods.
文摘A new museum in Fujian Province shines a spotlight on major discoveries linking the roots of Austronesian people to the Chinese mainland Amajor chapter in the story of humanity’s maritime past has come to light with the recent opening of the Keqiutou Site Branch of the China Archaeology Museum in Pingtan,Fujian Province,on April 9.
文摘Despite China's economy maintaining its electrifying annual growth, over 10 percent since 2003, the country has somehow successfully kept its inflation rate at relatively low levels. This growth pattern, which contradicts traditional theories in economics, is challenging many world-renowned economists to speculate on this phenomenon. Fan Gang, Director of the National Economic Research Institute under the China Reform Foundation, and Justin Yifu Lin, Director of the China Center for Economic Research of Peking University, gave their explanations for China's economic miracle at this April's Bo'ao Forum for Asia.
文摘Scientists are striving to overcome the difficulties in earthquake predictionAt 11:56 a.m. on July 4, those who were indoors in Beijing felt the earth shake like a boat in a mild storm. A few minutes later, they learned from radio. TV or the Internet that the epi- center of the magnitude 5.1 earthquake was in Wenan County, Hehei Province, 110
文摘这是一则科技珍闻。英国的科学家最近发现一种名叫scrub jays(【鸟】灌丛鸦)的鸟具有一直被认为是人类所独有的短暂记忆。对这种鸟的研究的价值 在于:…provides new tools to investigate how space, time and events areremembered in the human brain.这种研究可能为早老年痴呆病患者以及记忆缺失患者带来好消息。
文摘While reading plays a very important role in English study, many English language learners find it very difficult to fully comprehend some reading materials on account of many unknown words in them. This essay mainly discusses one technique of guessing meanings of new words according to context clues, thus emphasizing the importance of context.
文摘Students often have difficulties in reading comprehension because of too many new and unfamiliar words,too little background knowledge and different patterns of thinking among different countries.In this thesis,I recommend applying context clues,synonyms or antonyms,examples,definitions or explanations,cause/effect clues and background clues to make inference when we read texts.
