In their study,association of daily sitting time and leisure-time physical activity (LTPA) with body fat among U.S.Adults,Liao et al.^(1) analyzed data from the 2011-2018 National Health and Examination Survey to exam...In their study,association of daily sitting time and leisure-time physical activity (LTPA) with body fat among U.S.Adults,Liao et al.^(1) analyzed data from the 2011-2018 National Health and Examination Survey to examine associations between h/day sitting,meeting (or not meeting) the U.S.Physical Activity Guidelines of≥150 min/week of moderate-and vigorous-intensity LTPA,and combinations of sitting time and LTPA on totaland trunk percent body fat (BF%).展开更多
This paper delves into the intricate interplay between artificial intelligence(AI)systems and the perpetuation of Anti-Black racism within the United States medical industry.Despite the promising potential of AI to en...This paper delves into the intricate interplay between artificial intelligence(AI)systems and the perpetuation of Anti-Black racism within the United States medical industry.Despite the promising potential of AI to enhance healthcare outcomes and reduce disparities,there is a growing concern that these technologies may inadvertently/advertently exacerbate existing racial inequalities.Focusing specifically on the experiences of Black patients,this research investigates how the following AI components:medical algorithms,machine learning,and natural learning processes are contributing to the unequal distribution of medical resources,diagnosis,and health care treatment of those classified as Black.Furthermore,this review employs a multidisciplinary approach,combining insights from computer science,medical ethics,and social justice theory to analyze the mechanisms through which AI systems may encode and reinforce racial biases.By dissecting the three primary components of AI,this paper aims to present a clear understanding of how these technologies work,how they intersect,and how they may inherently perpetuate harmful stereotypes resulting in negligent outcomes for Black patients.Furthermore,this paper explores the ethical implications of deploying AI in healthcare settings and calls for increased transparency,accountability,and diversity in the development and implementation of these technologies.Finally,it is important that I prefer the following paper with a clear and concise definition of what I refer to as Anti-Black racism throughout the text.Therefore,I assert the following:Anti-Black racism refers to prejudice,discrimination,or antagonism directed against individuals or communities of African descent based on their race.It involves the belief in the inherent superiority of one race over another and the systemic and institutional practices that perpetuate inequality and disadvantage for Black people.Furthermore,I proclaim that this form of racism can be manifested in various ways,such as unequal access to opportunities,resources,education,employment,and fair treatment within social,economic,and political systems.It is also pertinent to acknowledge that Anti-Black racism is deeply rooted in historical and societal structures throughout the U.S.borders and beyond,leading to systemic disadvantages and disparities that impact the well-being and life chances of Black individuals and communities.Addressing Anti-Black racism involves recognizing and challenging both individual attitudes and systemic structures that contribute to discrimination and inequality.Efforts to combat Anti-Black racism include promoting awareness,education,advocacy for policy changes,and fostering a culture of inclusivity and equality.展开更多
The aim of this study was to investigate the adjustment problems of students from the United States enrolled in universities in the East,specifically in Taiwan,their problems related to cultural adaptation,and the pro...The aim of this study was to investigate the adjustment problems of students from the United States enrolled in universities in the East,specifically in Taiwan,their problems related to cultural adaptation,and the process of adjustment to student life in Taiwan.Under investigation were cultural adjustment and coping skills as these students transitioned from West to East.Qualitative data were collected from interviews with participants and faculty members as well as participant observations.Results indicated that U.S.students found their own ways to acclimate to their new academic setting as well as to social relations,cross-cultural issues,and the linguistic environment in Taiwan to achieve effective adaptation.They made changes in themselves to cope with all situations they encountered.This study provides suggestions for international students abroad in Taiwan,for the Taiwan Residents government,and for universities or colleges in terms of what they should offer to current and future international students.展开更多
The 100 men and women who make up the U.S.Senate will soon have an important choice.They will either affirm that the First Amendment matters or they will surrender to fear.The senators must decide whether to go along ...The 100 men and women who make up the U.S.Senate will soon have an important choice.They will either affirm that the First Amendment matters or they will surrender to fear.The senators must decide whether to go along with their colleagues in the House of Representatives and require the popular social media app TikTok to be sold to an American company.If they do endorse the House vote,then ByteDance must divest itself of TikTok or see the app will be banned on U.S.-based social media platforms.展开更多
The United States passed the Better Utilization of Investment Leading to Development(BUILD Act),as a counterweight to China’s overseas development activities.Under the Act,the US established a new federal agency,the ...The United States passed the Better Utilization of Investment Leading to Development(BUILD Act),as a counterweight to China’s overseas development activities.Under the Act,the US established a new federal agency,the U.S.International Development Finance Corporation(DFC),to enhance U.S.development financing capabilities.To better understand the impact of the DFC on China’s development finance,this article analyzes the DFC’s purpose,functions,structure,and funding.Then it focuses on the purpose of establishing the DFC,providing a preliminary analysis of the potential motivation for its establishment.It also compares the China Development Bank(CDB)and the DFC based on their focused sectors.Finally,through an in-depth analysis of financial frictions in China-U.S.relations,this article argues that the DFC competes with China’s overseas development financing activities in the context of broader strategic competition between China and the U.S.展开更多
Since the 1960s,the global natural gas industry has developed rapidly,and natural gas has become a fossil fuel that can balance supply stability,economic efficiency of consumption,clean and low-carbon features at the ...Since the 1960s,the global natural gas industry has developed rapidly,and natural gas has become a fossil fuel that can balance supply stability,economic efficiency of consumption,clean and low-carbon features at the current stage.However,there is a regional imbalance in the global demand for natural gas,and the continuous rise in geopolitical risks negatively affects the stability of the natural gas market.In recent years,LNG export capacity in the U.S.has continued to grow,and the potential for China-U.S.LNG trade in the future is enormous.From the perspective of development opportunities,strengthening LNG trade cooperation with the U.S.is conducive to the diversification of natural gas import sources for China.From the perspective of challenges,China-U.S.LNG trade cooperation also involves potential risks in terms of economy and channels.展开更多
The global supply chain is based on the global distribution of materials,technology,capital,labor,and markets and thus cannot be altered by political motives.KEEPING a sound and stable global supply chain will benefit...The global supply chain is based on the global distribution of materials,technology,capital,labor,and markets and thus cannot be altered by political motives.KEEPING a sound and stable global supply chain will benefit not only China and America,but also the world at large.Janet Yellen,U.S.secretary of treasury,has realized the devastating consequences of decoupling U.S.economy from Chinese economy when she spoke at John Hopkins Institute on April 20,2023.Yellen said,“The United States will assert ourselves when our vital interests are at stake.But we do not seek to decouple our economy from China’s.A full separation of our economies would be disastrous for both countries.It would be destabilizing for the rest of the world.”展开更多
At 1:35 p.m.local time on November 15,a four-hour summit between Chinese President Xi Jinping and U.S.President Joe Biden concluded at Filoli Estate in San Francisco.At a press briefing after the meeting,Wang Yi,membe...At 1:35 p.m.local time on November 15,a four-hour summit between Chinese President Xi Jinping and U.S.President Joe Biden concluded at Filoli Estate in San Francisco.At a press briefing after the meeting,Wang Yi,member of the Political Bureau of the CPC Central Committee and Minister of Foreign Affairs,said that“the two presidents had a very good,comprehensive,and in-depth meeting.”展开更多
Marble is widely used in construction industry mainly in interior & exterior design of buildings due to its resilient physical, chemical & mechanical properties. The diverse geology of Gilgit Baltistan has nat...Marble is widely used in construction industry mainly in interior & exterior design of buildings due to its resilient physical, chemical & mechanical properties. The diverse geology of Gilgit Baltistan has naturally endowed this region with different varieties of marble deposits. These marble deposits need proper characterization to ensure their proper use in the construction industry. This research aims to conduct a preliminary study for the characterization of the Nasir Abad Hunza marble deposit. Samples from said deposit were subjected to different tests to study its chemical, physical and mechanical properties. Results of XRF analysis reveal that the deposit under study is dolomitic. The comparison of different physical properties of deposits with standard values confirms its originality. However, high variation in the strength of core samples was observed, which could result from incomplete crystallization by metamorphism. This variation in the strength of samples suggests strength-based definitions of deposit domains to propose the use of each domain separately.展开更多
语言作为人类精神的产物和文明的载体应具有审美价值,而演讲作为一种特殊的语言表现形式,它的审美价值在于能够使受众在愉悦中自觉地去接受或容纳演讲的主旨。Speech on Hitler’s Invasion of the U.S.S.R.是丘吉尔政治生涯中重要的演...语言作为人类精神的产物和文明的载体应具有审美价值,而演讲作为一种特殊的语言表现形式,它的审美价值在于能够使受众在愉悦中自觉地去接受或容纳演讲的主旨。Speech on Hitler’s Invasion of the U.S.S.R.是丘吉尔政治生涯中重要的演讲作品之一,既具有时效性和实效性,又具有历久弥新的语言审美价值。展开更多
Proton exchange membrane fuel cells(PEMFC)have attracted much attention because of their high energy conversion efficiency,high power density and zero emission of pollutants.However,the high cost of the cathode platin...Proton exchange membrane fuel cells(PEMFC)have attracted much attention because of their high energy conversion efficiency,high power density and zero emission of pollutants.However,the high cost of the cathode platinum group metal(PGM)catalysts creates a barrier for the large-scale application of PEMFC.Tremendous efforts have been devoted to the development of low-cost PGM-free catalysts,especially the Fe-N-C catalysts,to replace the expensive PGM catalysts.However,the characterization methods and evaluation standards of the catalysts varies,which is not conducive to the comparison of PGM-free catalysts.U.S.Department of energy(DOE)is the only authority that specifies the testing standards and activity targets for PGM-free catalysts.In this review,the major breakthroughs of Fe-N-C catalysts are outlined with the reference of DOE standards and targets.The preparation and characteristics of these highly active Fe-N-C catalysts are briefly introduced.Moreover,the efforts on improving the mass transfer and the durability issue of Fe-N-C fuel cell are discussed.Finally,the prospective directions concerning the comprehensive evaluation of the Fe-N-C catalysts are proposed.展开更多
Objective:China and the United States(the U.S.)have the heaviest colorectal cancer(CRC)burden with considerable variations in temporal trends.This study aims to analyze the temporal patterns of CRC burden and its risk...Objective:China and the United States(the U.S.)have the heaviest colorectal cancer(CRC)burden with considerable variations in temporal trends.This study aims to analyze the temporal patterns of CRC burden and its risk factors in China and the U.S.across the past three decades.Methods:Data were extracted from the Global Burden of Disease(GBD)Study in 2019,including cases,deaths,disability-adjusted life-years(DALYs),age-standardized rate(ASR),and summary exposure value(SEV)of CRC in China and the U.S.between 1990 and 2019.Annual average percentage changes(AAPCs)of CRC burden were calculated using the Joinpoint regression model.The mortality in CRC attributable to potential risk factors was characterized by countries,gender,and age groups.Results:In 2019,there were 607,900 and 227,241 CRC cases,and 261,777 and 84,026 CRC deaths in China and the U.S.,respectively.The age-standardized incidence rate(ASIR)was 30.55 per 100,000 in China and 41.86 per100,000 in the U.S.,and the age-standardized mortality rate(ASMR)was 13.86 per 100,000 in China and 14.77 per100,000 in the U.S.CRC incidence,mortality,and DALY rate in the U.S.showed downward trends in the past three decades(AAPC=-0.47,-1.06,and-0.88,respectively),while upward trends were observed in China(AAPC=3.11,1.05,and 0.91,respectively).Among the cause of CRC,the leading risk factor contributing to CRC death was low milk in China and smoking in the U.S.,respectively.Conclusions:From 1990 to 2019,the burden of CRC in China increased dramatically,particularly for males and middle-aged and elderly people.The management of the major risk factors associated with the high burden of CRC should be enhanced.展开更多
This study examines the development and trends of China’s alfalfa market and imports, identifies key factors for the rapid increase in China’s alfalfa imports, and discusses potential impacts of the U.S.-China trade...This study examines the development and trends of China’s alfalfa market and imports, identifies key factors for the rapid increase in China’s alfalfa imports, and discusses potential impacts of the U.S.-China trade dispute and retaliations on the alfalfa markets and trade in both nations. China’s rapid transition toward larger-scale commercial dairy production, with enhanced feed and cost management as well as quality and safety control, and its limited resources for high-quality alfalfa production are key factors for the dramatic increase in its alfalfa imports, from 19 601 metric tons in 2008 to 1.38 million metric tons(mmt) in 2018. While the United States dominated China’s alfalfa imports with an average share of 97.01% from 2007 to 2017, the share dropped to 83.76% in 2018 and 63.28% in January 2019 due to the trade dispute and retaliations started in 2018. China will likely remain a large importer of alfalfa because of both its growing demand and the comparative advantages of imported alfalfa in quality and price, but the imports from the United States will be highly affected by the ongoing trade dispute and negotiations. China is also expected to make more efforts to reduce its dependence on U.S. alfalfa through increased investment in domestic alfalfa production and identification of alternative sources of alfalfa and other hay imports.展开更多
The global community has prepared for the withdrawal of the U.S. from the Paris Agreement since Donald Trump was elected as the president of the U.S. However, Trump's formal declaration of withdrawal still caused ...The global community has prepared for the withdrawal of the U.S. from the Paris Agreement since Donald Trump was elected as the president of the U.S. However, Trump's formal declaration of withdrawal still caused worldwide reaction. Trump will use the withdrawal to build his political reputation and to renegotiate the Paris Agreement despite its negative effects on the political credibility, international relationships, and potential long-term economic growth of the U.S. In general, the withdrawal of the U.S. from the Paris Agreement will not change the development of low-carbon technologies and the transformation trend of the global climate governance regime. However, the long-term goals and international cooperation on climate change will be affected by budget cuts in American climate change research and the cancelation of donations from the multilateral environmental fund of the U.S. If the Paris Agreement is renegotiated, the common but differentiated principle of responsibility of the United Nations Framework Convention on Climate Change will be challenged again. Nevertheless, climate change governance remains a main theme of future sustainable development. Instead of national governments, local governments and non-governmental organizations will develop strategies for technical innovation and emphasize pragmatic cooperation, thus expanding their roles in climate change governance. The capacity building on climate change research and public awareness should be enhanced as a long-term objective of global climate change governance.展开更多
The coal mine roof rating(CMRR) was developed to bridge the gap between geological variation in underground coal mines and engineering design. The CMRR accounts for the compressive strength of the immediate roof, the ...The coal mine roof rating(CMRR) was developed to bridge the gap between geological variation in underground coal mines and engineering design. The CMRR accounts for the compressive strength of the immediate roof, the shear strength and intensity of any discontinuities present, and the moisture sensitivity of the immediate roof. The CMRR has been widely used and validated in Eastern US coal mines, but it has seen limited application in the Western US. This study focuses on roof behavior at a Western coal mine(Mine A). Mine A shows significant lateral geological variation, along with localized faulting and a laterally extensive sandstone channel network. The CMRR is not used to predict roof instability at the mine. It is, therefore, hypothesized that there are other factors that are correlated with roof instability in underground coal mines that could potentially also be considered in conjunction with the CMRR.This hypothesis was tested by collecting 30 CMRR measurements at Mine A. At each measurement location, a binary record of the roof condition(stable or unstable) was made, and other parameters such as depth of cover, presence of faulting, and sandstone channels were also recorded. ANOVA tests showed that the CMRR values and the roof conditions were not strongly correlated, indicating that the CMRR input criteria are not fully predictive of roof stability at this mine. The CMRR values showed statistically significant correlations(p less than 0.05) with faulting as well as with location at an intersection. For areas that had previously experienced roof fall but were currently stable, faulting was correlated with roof condition(p less than 0.05) only when the condition was classified as unstable.展开更多
Based on the Computable General Equilibrium (CGE) model and scenario analysis, the impacts of the U.S. withdrawal from the Paris Agreement on the carbon emission space and mitigation cost in China, European Union (EU)...Based on the Computable General Equilibrium (CGE) model and scenario analysis, the impacts of the U.S. withdrawal from the Paris Agreement on the carbon emission space and mitigation cost in China, European Union (EU), and Japan are assessed under Nationally Determined Contributions (NDCs) and 2 C scenarios due to the changed emission pathway of the U.S. The results show that, under the condition of constant global cumulative carbon emissions and a fixed burden-sharing scheme among countries, the failure of the U.S. to honor its NDC commitment to different degrees will increase the U.S. carbon emission space and decrease its mitigation cost. However, the carbon emission space of other parties, including China, EU, and Japan, will be reduced and their mitigation costs will be increased. In 2030, under the 2 C target, the carbon price will increase by 4.4e14.6 US$ t1 in China, by 9.7e35.4 US$ t1 in the EU, and by 16.0e53.5 US$ t1 in Japan. In addition, China, EU, and Japan will incur additional Gross Domestic Production (GDP) loss. Under the 2 C target, the GDP loss of China would increase by US$22.0e71.1 billion (equivalent to 16.4e53.1 US$ per capita), the EU's GDP loss would increase by US$9.4e32.1 billion (equivalent to 20.7e71.1 US$ per capita), and Japan's GDP loss will increase by US$4.1e13.5 billion (equivalent to 34.3e111.6 US$ per capita).展开更多
Accessibility is a factor affecting national park visitation.However,the effect of accessibility on national park visitation is not fully understood.This paper examines the relationship between U.S.national park visit...Accessibility is a factor affecting national park visitation.However,the effect of accessibility on national park visitation is not fully understood.This paper examines the relationship between U.S.national park visitation and accessibility.First,the global and local accessibility indexes of each park unit are computed based on an accessibility model that takes into account the surrounding population and its proximity to the park unit.Integrated in the model is a distance decay coefficient that is derived from U.S.national park visitor surveys and therefore pertinent to the case of study.Then correlation analysis is performed between park visitation and accessibility based on park types,regions,and visitation types.Results show that total visitation is positively related to accessibility in National Memorials,Military Parks and Battlefield Parks/Sites but negatively related to accessibility in national parks and national monuments.However,recreational overnight stay visits are commonly negatively correlated to accessibility for almost all park types.Moreover,local accessibility index displays enhanced correlation coefficients with improved significance levels in many categories of analysis.Results suggest that historical/cultural national parks which often show positive correlations tend to attract more local visitors,but nature-based parks which mainly show negative correlations tend to attract more distant visitors.展开更多
文摘In their study,association of daily sitting time and leisure-time physical activity (LTPA) with body fat among U.S.Adults,Liao et al.^(1) analyzed data from the 2011-2018 National Health and Examination Survey to examine associations between h/day sitting,meeting (or not meeting) the U.S.Physical Activity Guidelines of≥150 min/week of moderate-and vigorous-intensity LTPA,and combinations of sitting time and LTPA on totaland trunk percent body fat (BF%).
文摘This paper delves into the intricate interplay between artificial intelligence(AI)systems and the perpetuation of Anti-Black racism within the United States medical industry.Despite the promising potential of AI to enhance healthcare outcomes and reduce disparities,there is a growing concern that these technologies may inadvertently/advertently exacerbate existing racial inequalities.Focusing specifically on the experiences of Black patients,this research investigates how the following AI components:medical algorithms,machine learning,and natural learning processes are contributing to the unequal distribution of medical resources,diagnosis,and health care treatment of those classified as Black.Furthermore,this review employs a multidisciplinary approach,combining insights from computer science,medical ethics,and social justice theory to analyze the mechanisms through which AI systems may encode and reinforce racial biases.By dissecting the three primary components of AI,this paper aims to present a clear understanding of how these technologies work,how they intersect,and how they may inherently perpetuate harmful stereotypes resulting in negligent outcomes for Black patients.Furthermore,this paper explores the ethical implications of deploying AI in healthcare settings and calls for increased transparency,accountability,and diversity in the development and implementation of these technologies.Finally,it is important that I prefer the following paper with a clear and concise definition of what I refer to as Anti-Black racism throughout the text.Therefore,I assert the following:Anti-Black racism refers to prejudice,discrimination,or antagonism directed against individuals or communities of African descent based on their race.It involves the belief in the inherent superiority of one race over another and the systemic and institutional practices that perpetuate inequality and disadvantage for Black people.Furthermore,I proclaim that this form of racism can be manifested in various ways,such as unequal access to opportunities,resources,education,employment,and fair treatment within social,economic,and political systems.It is also pertinent to acknowledge that Anti-Black racism is deeply rooted in historical and societal structures throughout the U.S.borders and beyond,leading to systemic disadvantages and disparities that impact the well-being and life chances of Black individuals and communities.Addressing Anti-Black racism involves recognizing and challenging both individual attitudes and systemic structures that contribute to discrimination and inequality.Efforts to combat Anti-Black racism include promoting awareness,education,advocacy for policy changes,and fostering a culture of inclusivity and equality.
文摘The aim of this study was to investigate the adjustment problems of students from the United States enrolled in universities in the East,specifically in Taiwan,their problems related to cultural adaptation,and the process of adjustment to student life in Taiwan.Under investigation were cultural adjustment and coping skills as these students transitioned from West to East.Qualitative data were collected from interviews with participants and faculty members as well as participant observations.Results indicated that U.S.students found their own ways to acclimate to their new academic setting as well as to social relations,cross-cultural issues,and the linguistic environment in Taiwan to achieve effective adaptation.They made changes in themselves to cope with all situations they encountered.This study provides suggestions for international students abroad in Taiwan,for the Taiwan Residents government,and for universities or colleges in terms of what they should offer to current and future international students.
文摘The 100 men and women who make up the U.S.Senate will soon have an important choice.They will either affirm that the First Amendment matters or they will surrender to fear.The senators must decide whether to go along with their colleagues in the House of Representatives and require the popular social media app TikTok to be sold to an American company.If they do endorse the House vote,then ByteDance must divest itself of TikTok or see the app will be banned on U.S.-based social media platforms.
文摘The United States passed the Better Utilization of Investment Leading to Development(BUILD Act),as a counterweight to China’s overseas development activities.Under the Act,the US established a new federal agency,the U.S.International Development Finance Corporation(DFC),to enhance U.S.development financing capabilities.To better understand the impact of the DFC on China’s development finance,this article analyzes the DFC’s purpose,functions,structure,and funding.Then it focuses on the purpose of establishing the DFC,providing a preliminary analysis of the potential motivation for its establishment.It also compares the China Development Bank(CDB)and the DFC based on their focused sectors.Finally,through an in-depth analysis of financial frictions in China-U.S.relations,this article argues that the DFC competes with China’s overseas development financing activities in the context of broader strategic competition between China and the U.S.
文摘Since the 1960s,the global natural gas industry has developed rapidly,and natural gas has become a fossil fuel that can balance supply stability,economic efficiency of consumption,clean and low-carbon features at the current stage.However,there is a regional imbalance in the global demand for natural gas,and the continuous rise in geopolitical risks negatively affects the stability of the natural gas market.In recent years,LNG export capacity in the U.S.has continued to grow,and the potential for China-U.S.LNG trade in the future is enormous.From the perspective of development opportunities,strengthening LNG trade cooperation with the U.S.is conducive to the diversification of natural gas import sources for China.From the perspective of challenges,China-U.S.LNG trade cooperation also involves potential risks in terms of economy and channels.
文摘The global supply chain is based on the global distribution of materials,technology,capital,labor,and markets and thus cannot be altered by political motives.KEEPING a sound and stable global supply chain will benefit not only China and America,but also the world at large.Janet Yellen,U.S.secretary of treasury,has realized the devastating consequences of decoupling U.S.economy from Chinese economy when she spoke at John Hopkins Institute on April 20,2023.Yellen said,“The United States will assert ourselves when our vital interests are at stake.But we do not seek to decouple our economy from China’s.A full separation of our economies would be disastrous for both countries.It would be destabilizing for the rest of the world.”
文摘At 1:35 p.m.local time on November 15,a four-hour summit between Chinese President Xi Jinping and U.S.President Joe Biden concluded at Filoli Estate in San Francisco.At a press briefing after the meeting,Wang Yi,member of the Political Bureau of the CPC Central Committee and Minister of Foreign Affairs,said that“the two presidents had a very good,comprehensive,and in-depth meeting.”
文摘Marble is widely used in construction industry mainly in interior & exterior design of buildings due to its resilient physical, chemical & mechanical properties. The diverse geology of Gilgit Baltistan has naturally endowed this region with different varieties of marble deposits. These marble deposits need proper characterization to ensure their proper use in the construction industry. This research aims to conduct a preliminary study for the characterization of the Nasir Abad Hunza marble deposit. Samples from said deposit were subjected to different tests to study its chemical, physical and mechanical properties. Results of XRF analysis reveal that the deposit under study is dolomitic. The comparison of different physical properties of deposits with standard values confirms its originality. However, high variation in the strength of core samples was observed, which could result from incomplete crystallization by metamorphism. This variation in the strength of samples suggests strength-based definitions of deposit domains to propose the use of each domain separately.
文摘语言作为人类精神的产物和文明的载体应具有审美价值,而演讲作为一种特殊的语言表现形式,它的审美价值在于能够使受众在愉悦中自觉地去接受或容纳演讲的主旨。Speech on Hitler’s Invasion of the U.S.S.R.是丘吉尔政治生涯中重要的演讲作品之一,既具有时效性和实效性,又具有历久弥新的语言审美价值。
基金supported by the National Thousand Talents Plan of Chinathe National Natural Science Foundation of China(Grant Nos.21673014 and U1766216)+1 种基金the 111 project(B17002)funded by the Ministry of Education of Chinathe Fundamental Research Funds for the Central Universities of China
文摘Proton exchange membrane fuel cells(PEMFC)have attracted much attention because of their high energy conversion efficiency,high power density and zero emission of pollutants.However,the high cost of the cathode platinum group metal(PGM)catalysts creates a barrier for the large-scale application of PEMFC.Tremendous efforts have been devoted to the development of low-cost PGM-free catalysts,especially the Fe-N-C catalysts,to replace the expensive PGM catalysts.However,the characterization methods and evaluation standards of the catalysts varies,which is not conducive to the comparison of PGM-free catalysts.U.S.Department of energy(DOE)is the only authority that specifies the testing standards and activity targets for PGM-free catalysts.In this review,the major breakthroughs of Fe-N-C catalysts are outlined with the reference of DOE standards and targets.The preparation and characteristics of these highly active Fe-N-C catalysts are briefly introduced.Moreover,the efforts on improving the mass transfer and the durability issue of Fe-N-C fuel cell are discussed.Finally,the prospective directions concerning the comprehensive evaluation of the Fe-N-C catalysts are proposed.
基金Sanming Project of Medicine in Shenzhen(No.SZSM201911015)。
文摘Objective:China and the United States(the U.S.)have the heaviest colorectal cancer(CRC)burden with considerable variations in temporal trends.This study aims to analyze the temporal patterns of CRC burden and its risk factors in China and the U.S.across the past three decades.Methods:Data were extracted from the Global Burden of Disease(GBD)Study in 2019,including cases,deaths,disability-adjusted life-years(DALYs),age-standardized rate(ASR),and summary exposure value(SEV)of CRC in China and the U.S.between 1990 and 2019.Annual average percentage changes(AAPCs)of CRC burden were calculated using the Joinpoint regression model.The mortality in CRC attributable to potential risk factors was characterized by countries,gender,and age groups.Results:In 2019,there were 607,900 and 227,241 CRC cases,and 261,777 and 84,026 CRC deaths in China and the U.S.,respectively.The age-standardized incidence rate(ASIR)was 30.55 per 100,000 in China and 41.86 per100,000 in the U.S.,and the age-standardized mortality rate(ASMR)was 13.86 per 100,000 in China and 14.77 per100,000 in the U.S.CRC incidence,mortality,and DALY rate in the U.S.showed downward trends in the past three decades(AAPC=-0.47,-1.06,and-0.88,respectively),while upward trends were observed in China(AAPC=3.11,1.05,and 0.91,respectively).Among the cause of CRC,the leading risk factor contributing to CRC death was low milk in China and smoking in the U.S.,respectively.Conclusions:From 1990 to 2019,the burden of CRC in China increased dramatically,particularly for males and middle-aged and elderly people.The management of the major risk factors associated with the high burden of CRC should be enhanced.
基金the Vermont Agricultural Experiment Station at the University Vermont,USA,and the National Social Science Fund of China(17ZDA067)for financial support of this project。
文摘This study examines the development and trends of China’s alfalfa market and imports, identifies key factors for the rapid increase in China’s alfalfa imports, and discusses potential impacts of the U.S.-China trade dispute and retaliations on the alfalfa markets and trade in both nations. China’s rapid transition toward larger-scale commercial dairy production, with enhanced feed and cost management as well as quality and safety control, and its limited resources for high-quality alfalfa production are key factors for the dramatic increase in its alfalfa imports, from 19 601 metric tons in 2008 to 1.38 million metric tons(mmt) in 2018. While the United States dominated China’s alfalfa imports with an average share of 97.01% from 2007 to 2017, the share dropped to 83.76% in 2018 and 63.28% in January 2019 due to the trade dispute and retaliations started in 2018. China will likely remain a large importer of alfalfa because of both its growing demand and the comparative advantages of imported alfalfa in quality and price, but the imports from the United States will be highly affected by the ongoing trade dispute and negotiations. China is also expected to make more efforts to reduce its dependence on U.S. alfalfa through increased investment in domestic alfalfa production and identification of alternative sources of alfalfa and other hay imports.
文摘The global community has prepared for the withdrawal of the U.S. from the Paris Agreement since Donald Trump was elected as the president of the U.S. However, Trump's formal declaration of withdrawal still caused worldwide reaction. Trump will use the withdrawal to build his political reputation and to renegotiate the Paris Agreement despite its negative effects on the political credibility, international relationships, and potential long-term economic growth of the U.S. In general, the withdrawal of the U.S. from the Paris Agreement will not change the development of low-carbon technologies and the transformation trend of the global climate governance regime. However, the long-term goals and international cooperation on climate change will be affected by budget cuts in American climate change research and the cancelation of donations from the multilateral environmental fund of the U.S. If the Paris Agreement is renegotiated, the common but differentiated principle of responsibility of the United Nations Framework Convention on Climate Change will be challenged again. Nevertheless, climate change governance remains a main theme of future sustainable development. Instead of national governments, local governments and non-governmental organizations will develop strategies for technical innovation and emphasize pragmatic cooperation, thus expanding their roles in climate change governance. The capacity building on climate change research and public awareness should be enhanced as a long-term objective of global climate change governance.
基金supported by a NIOSH Capacity Building grant (No. 200-2016-90154) to Drs. G. Walton and E. Holley and collaborators at the Colorado School of Mines
文摘The coal mine roof rating(CMRR) was developed to bridge the gap between geological variation in underground coal mines and engineering design. The CMRR accounts for the compressive strength of the immediate roof, the shear strength and intensity of any discontinuities present, and the moisture sensitivity of the immediate roof. The CMRR has been widely used and validated in Eastern US coal mines, but it has seen limited application in the Western US. This study focuses on roof behavior at a Western coal mine(Mine A). Mine A shows significant lateral geological variation, along with localized faulting and a laterally extensive sandstone channel network. The CMRR is not used to predict roof instability at the mine. It is, therefore, hypothesized that there are other factors that are correlated with roof instability in underground coal mines that could potentially also be considered in conjunction with the CMRR.This hypothesis was tested by collecting 30 CMRR measurements at Mine A. At each measurement location, a binary record of the roof condition(stable or unstable) was made, and other parameters such as depth of cover, presence of faulting, and sandstone channels were also recorded. ANOVA tests showed that the CMRR values and the roof conditions were not strongly correlated, indicating that the CMRR input criteria are not fully predictive of roof stability at this mine. The CMRR values showed statistically significant correlations(p less than 0.05) with faulting as well as with location at an intersection. For areas that had previously experienced roof fall but were currently stable, faulting was correlated with roof condition(p less than 0.05) only when the condition was classified as unstable.
基金This study was supported by the 2017 National Natural Science Foundation Project “The Impacts of U.S. Withdrawal from Paris Agreement on Global Climate Governance and China's Response”.
文摘Based on the Computable General Equilibrium (CGE) model and scenario analysis, the impacts of the U.S. withdrawal from the Paris Agreement on the carbon emission space and mitigation cost in China, European Union (EU), and Japan are assessed under Nationally Determined Contributions (NDCs) and 2 C scenarios due to the changed emission pathway of the U.S. The results show that, under the condition of constant global cumulative carbon emissions and a fixed burden-sharing scheme among countries, the failure of the U.S. to honor its NDC commitment to different degrees will increase the U.S. carbon emission space and decrease its mitigation cost. However, the carbon emission space of other parties, including China, EU, and Japan, will be reduced and their mitigation costs will be increased. In 2030, under the 2 C target, the carbon price will increase by 4.4e14.6 US$ t1 in China, by 9.7e35.4 US$ t1 in the EU, and by 16.0e53.5 US$ t1 in Japan. In addition, China, EU, and Japan will incur additional Gross Domestic Production (GDP) loss. Under the 2 C target, the GDP loss of China would increase by US$22.0e71.1 billion (equivalent to 16.4e53.1 US$ per capita), the EU's GDP loss would increase by US$9.4e32.1 billion (equivalent to 20.7e71.1 US$ per capita), and Japan's GDP loss will increase by US$4.1e13.5 billion (equivalent to 34.3e111.6 US$ per capita).
基金supported by the National Nature Science Foundation of China (Grant No. 41401604)the Central Universities Fund Project of Southwest Minzu University (Grant No. 2019SYB07)
文摘Accessibility is a factor affecting national park visitation.However,the effect of accessibility on national park visitation is not fully understood.This paper examines the relationship between U.S.national park visitation and accessibility.First,the global and local accessibility indexes of each park unit are computed based on an accessibility model that takes into account the surrounding population and its proximity to the park unit.Integrated in the model is a distance decay coefficient that is derived from U.S.national park visitor surveys and therefore pertinent to the case of study.Then correlation analysis is performed between park visitation and accessibility based on park types,regions,and visitation types.Results show that total visitation is positively related to accessibility in National Memorials,Military Parks and Battlefield Parks/Sites but negatively related to accessibility in national parks and national monuments.However,recreational overnight stay visits are commonly negatively correlated to accessibility for almost all park types.Moreover,local accessibility index displays enhanced correlation coefficients with improved significance levels in many categories of analysis.Results suggest that historical/cultural national parks which often show positive correlations tend to attract more local visitors,but nature-based parks which mainly show negative correlations tend to attract more distant visitors.