Commentary on "Association of daily sitting time and leisure-time physical activity with body fat among U.S.adults"

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%).

Cross-Cultural Adjustment and Coping:U.S.Students in Taiwan Residents Higher Education

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.

EU vs. U.S. , Russia and China

Since George W. Bush assumed the presidency in early 2001, a tense situation had occurred in the relationships among world big powers. In the aftermath of September 11,significant improvement has been made in Sino-U.S. and Russia-U. S. relations. In the meantime, corresponding changes have taken place in EU-U. S.and Russia-China relations.

Comparison of Corn Production Costs in China,the U.S. and Brazil and Its Implications

This paper analyzes the corn production cost in China, the U.S. and Brazil from 1997 to 2014. According to the results,（1） corn production cost in China is the highest among these three countries;（2） the rapid growth of labor cost and land cost is the major factor that promotes the increase of total corn production cost in China;（3） the level of agricultural mechanization in China has been gradually improving, and the gap between agricultural mechanization levels in China and other two countries is constantly narrowing;（4） differing from the U.S. and Brazil,China exhibits a ＂high input, low output＂ agricultural production mode. Based on the above analyses, corresponding suggestions have been presented to reduce corn production cost in China.

China’s alfalfa market and imports: Development, trends, and potential impacts of the U.S.-China trade dispute and retaliations

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.

The withdrawal of the U.S. from the Paris Agreement and its impact on global climate change governance

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.

The impacts of U.S. withdrawal from the Paris Agreement on the carbon emission space and mitigation cost of China, EU, and Japan under the constraints of the global carbon emission space

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).

U.S. national parks accessibility and visitation

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.

Measures and Strategic Conception of Japan to Deal with the Russia–Ukraine Crisis

After the outbreak of the Russia–Ukraine conflict, Japan wasted no time in advancing its national strategy and actively promoted shuttle diplomacy with the United States(U.S.), Europe, East Asia, and neighboring countries of Ukraine around sanctions against Russia based on strategic considerations and the goal of maximizing national interests. Japan regarded this conflict as an important opportunity for an international strategic game, in an attempt to move and overturn the postwar international order and reconstruct the new global order with the U.S., Europe, and Japan as the core countries dominating the military, science and technology, and economic spheres. In response to the crisis, Japan made a brief policy adjustment—from the initial hesitation to the imposition of active sanctions and pressure on Russia—to reverse the passive situation on the issue of the Four Northern Islands and weaken Russia’s strength. Japan also took the opportunity to promote the “China threat theory”;strengthen the quadrilateral mechanism between the U.S., Japan, India, and Australia;provoke regional confrontation;and try to gain a new Cold War dividend.

Methane Generation and Capture of U.S.Landfills

Analysis of the U.S.EPA(Environmental Protection Agency)database of 2,549 MSW(Municipal Solid Waste)landfills showed that there were 1,164 operating landfills in which 348 million short tons(316 million metric tons)of waste were landfilled in 2017.In total,these landfills occupy about 370 million square meters of land so it is not possible to monitor the generation of LFG(Landfill Gas)generation accurately,or collect most of the LFG generated.This study was based on the hypothesis that,on the average,methane generation is proportional to the tonnage of wastes landfilled annually.The Landfill Methane Outreach Program of the EPA(EPA-LMOP)compiles annual operating data of all methane-capturing landfills.Our analysis of the 2018 data for 396 LMOP operating landfills showed that 210 million short tons of wastes were deposited and 5.06 million short tons of methane were captured,i.e.,an average capture of 0.024-ton CH4/ton waste.On the basis of the anaerobic reaction of the DOC(Degradable Organic Carbon)in landfilled wastes,the average rate of methane generation from all operating U.S.landfills was estimated to be 0.05 ton of CH4 per ton of annual capacity;this number corresponds to bioreaction of about one half of the total organic carbon in MSW.On this basis,the average rate of CH4 emission from the 396 LMOP landfills was estimated to be 0.026-ton CH4 per annual ton of deposition and the average efficiency of LFG capture,48%.Adding up all 1,164 operating landfills,their total emission of methane was estimated at 11.9 million metric tons of CH4.At CH4/CO2 equivalence of 25,this number corresponds to CO2-eq emissions of 270 million metric tons,i.e.,5.1%of the U.S.energy related carbon dioxide emissions.

Effects of Planting Date on Winter Canola Growth and Yield in the Southwestern U.S.

Canola (Brassica napus L.) has potential to become alternative cash crop (healthy oil for human and meals for animal uses) with tremendous rotational benefits in the Southwestern U.S., a region dominated by cereal-fallow cropping systems. However, information on optimum planting date for its successful production is limited. Field experiments were conducted in 2011-12 and 2012-13 seasons under irrigation condition to study the response of canola growth and yield to planting dates at Clovis, NM. Three planting dates (mid-September, late-September and early-October) and four canola varieties (early flowering: DKW41-10 and DKW46-15;medium flowering: Riley and Wichita) are studied. Fall plant stand density is significantly higher for early-October than mid- and late-September plantings. However, a ratio of fall to spring plant stand density indicates a greater reduction in spring plant stand density with early-October (25%) and mid-September (19%) than late-September (7%). Vegetative (by 13 days) and flowering (by 7 days) duration phases are significantly shortened with delay in planting. The decline in aboveground dry matter (DM) due to delayed planting resulted in significant seed yield reduction in both 2011-12 (26%) and in 2012-13 (8%) when early-October and mid-September plantings were compared. There was a positive relationship between final DM and canola seed yield, accounting for 84 and 34% variation for 2011-12 and 2012-13 seasons, respectively with the 2011-12 environmental conditions being conducive for genetically controlled variation in DM production to be more apparent and strong in explaining the variation in seed yield among varieties. Medium-flowering varieties produced higher DM (9741 vs. 8371 Kg•ha-1) and seed yield (2785 vs. 2035 Kg•ha-1) than early-flowering varieties. In addition to seed yield, DM can be used as an indirect selection criterion for seed yield in variety selection and appropriate planting dates including a guarantee for high crop residues (~75% of the total aboveground biomass) production to make canola a potential alternative cash and rotational break crop in the Southwestern U.S.

COVID‑19 and instability of stock market performance:evidence from the U.S.

The effect of COVID-19 on stock market performance has important implications for both financial theory and practice.This paper examines the relationship between COVID-19 and the instability of both stock return predictability and price volatility in the U.S over the period January 1st,2019 to June 30th,2020 by using the methodologies of Bai and Perron(Econometrica 66:47–78,1998.https://doi.org/10.2307/2998540;J Appl Econo 18:1–22,2003.https://doi.org/10.1002/jae.659),Elliot and Muller(Optimal testing general breaking processes in linear time series models.University of California at San Diego Economic Working Paper,2004),and Xu(J Econ 173:126–142,2013.https://doi.org/10.1016/j.jecon om.2012.11.001).The results highlight a single break in return predictability and price volatility of both S&P 500 and DJIA.The timing of the break is consistent with the COVID-19 outbreak,or more specifically the stock sellingoffs by the U.S.senate committee members before COVID-19 crashed the market.Furthermore,return predictability and price volatility significantly increased following the derived break.The findings suggest that the pandemic crisis was associated with market inefficiency,creating profitable opportunities for traders and speculators.Furthermore,it also induced income and wealth inequality between market participants with plenty of liquidity at hand and those short of funds.

Assessment of China's International Environment and U.S. Strategic Trend

It is of great significance to have a clear understanding of the international environment that China faces. But this is an uneasy job. Since September 11, the world situation has become so complicated that it is hard to grasp its essence even with painstaking efforts. To judge such an already complicated international environment from China’s perspective adds more difficulties, for different people usually have different views due to the different angles from which they see the situation and different methods they adopt. This, understandably, leads to hot debates within the Chinese academic circles. To provide a stage for exchange of views, at the invitation of the CIR Expert Forum, some well-known scholars and experts on international relations from Beijing gathered to hold a symposium on November 5, 2002, with the theme of "How to assess the international environment that China faces". The speeches at the symposium will be published in two installments. Following are the first half.

Railroad capacity tools and methodologies in the U.S. and Europe

A growing demand for passenger and freight transportation, combined with limited capital to expand the United States （U.S.） rail infrastructure, is creating pressure for a more efficient use of the current line capacity. This is further exacerbated by the fact that most passenger rail services operate on corridors that are shared with freight traffic. A capacity analysis is one alternative to address the situation and there are various approaches, tools, and methodologies available for application. As the U.S. continues to develop higher speed passenger services with similar characteristics to those in European shared-use lines, understanding the common methods and tools used on both continents grows in relevance. There has not as yet been a detailed investigation as to how each continent approaches capacity analysis, and whether any benefits could be gained from cross-pollination. This paper utilizes more than 50 past capacity studies from the U.S. and Europe to describe the different railroad capacity defini- tions and approaches, and then categorizes them, based on each approach. The capacity methods are commonly di- vided into analytical and simulation methods, but this paper also introduces a third, ＂combined simulation- analytical＂ category. The paper concludes that Europeanrail studies are more unified in terms of capacity, concepts, and techniques, while the U.S. studies represent a greater variation in methods, tools, and objectives. The majority of studies on both continents use either simulation or a combined simulation-analytical approach. However, due to the significant differences between operating philosophy and network characteristics of these two rail systems, European studies tend to use timetable-based simulation tools as opposed to the non-timetable-based tools commonly used in the U.S. rail networks. It was also found that validation of studies against actual operations was not typically completed or was limited to comparisons with a base model.

Group Purchasing Organizations (GPOs) in the U.S.: Development and Reform

Objective To study the characteristics, specific functions and policy improvement process of the Group Purchasing Organizations (GPOs) in the U.S. and to provide references for drug group purchasing practices in China. Methods Domestic and foreign relevant literatures, websites were reviewed or searched to analyze the functions and policy improvement process of the GPOs in the U.S. so as to provide references for drug group purchasing practices in China. Results and Conclusion As a third party in the U.S. GPOs has formed a relatively integrated business process and projects service system after long-term development. Supported by corresponding policies and industrial regulations, GPOs have made a great contribution to control the growth of medical and healthcare expenses and improve the efficiency of medical institutions, and its development experience can enlighten the practices in China.

U.S. withdrawal from the Paris Agreement: Reasons, impacts, and China's response

Applying qualitative and quantitative methods, this article explains the driving forces behind U.S. President Donald Trump's decision to withdraw from the Paris Agreement, assesses the impacts of this withdrawal on the compliance prospects of the agreement, and proposes how China should respond. The withdrawal undercuts the foundation of global climate governance and upsets the process of climate cooperation, and the impacts are manifold. The withdrawal undermines the universality of the Paris Agreement and impairs states' confidence in climate cooperation; it aggravates the leadership deficit in addressing global climate issues and sets a bad precedent for international climate cooperation. The withdrawal reduces other countries' emission space and raises their emission costs, and refusal to contribute to climate aid makes it more difficult for developing countries to mitigate and adapt to climate change. Cutting climate research funding will compromise the quality of future IPCC reports and ultimately undermine the scientific authority of future climate negotiations. China faces mounting pressure from the international community to assume global climate leadership after the U.S. withdraws, and this article proposes that China should reach the high ends of its domestic climate targets under the current Nationally Determined Contributions; internationally, China should facilitate the rebuilding of shared climate leadership, replacing the G2 with C5. Meanwhile, China needs to keep the U.S. engaged in climate cooperation.

Russia's Precious Metals Market: Condition and Prospects

The region of existence of phases in equilibrium with the solid solution based on palladium. Presented to analyze the current situation in the market of precious metals in Russia. Provides information about the production and processing of precious metals. Prospects for the most likely path of development of the Russian market of precious metals.

Putin's Strategy of Integrating Russia into Europe and Its Prospect

The establishment and rapid rise of the European Union (EU) have increasingly made Europe an independent force. Objectively, the enlargement of both the EU and NATO has speeded up the process of European integration, and "One important link of Russia’s diplomacy

U.S. National Strategy: betweem Offensive and Integration

As the hegemonic country in the world system, U. S. national strategy is global and multi-directional. Since September 11, 2001, America has made series of adjustments in its global strategy, including adjustment in security focus and change of security means. Come what may, since America has become the superpower in the world system, its national strategy has always been between offensive and integration. In a sense, current American strategy is the combination of the two. Although different government would tilt toward one direction, none