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Grassland management practices in Chinese steppes impact productivity, diversity and the relationship

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Frontiers of Agricultural Science and Engineering 2018年第1期5卷 57-63页

作者： Yingjun ZHANG Wenjie LU Hao ZHANG Jiqiong ZHOU Yue SHEN Department of Grassland Science China Agricultural University

Grasslands are crucial parts of the terrestrial ecosystem, with an extremely high differentiation of productivity and diversity across spatial scales and land use patterns. The practices employed to manage grassland,such as grazing, haymaking, fertilization or reseeding, can improve the grassland condition. This study focuses on the changes in productivity and diversity and the relationship between them as affected by management practices.productivity and diversity have unequivocally been altered in response to different management practices. When grazing intensity of a typical steppe increased from 1.5 to 9 sheep per hectare, both productivity and diversity declined.Higher grazing intensity(6 to 9 sheep per hectare)accelerated loss of diversity because of lower productivity.productivity was significantly improved but diversity was lost by fertilizing. N fertilization also reduced the sensitivity of diversity to productivity. A similar response was found in mown grassland with increased productivity and diversity but their relationship was negatively affected.Mowing also slowed down the decline in diversity as productivity increased. Reseeding purple-flowered alfalfa led to an increased diversity, while yellow-flowered alfalfa increased productivity significantly. The negative productivity-diversity relationship was transformed to a positive one by reseeding alfalfa. These results enhance understanding of how productivity, diversity and their relationships change in response to altered grassland management practices, and support an integrated approach for improving both productivity and diversity.

关键词： diversity fertilizing grassland management practice grazing mowing productivity reseeding

Profitability and productivity of the Chinese Textile Industry

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China & World Economy 2010年第5期18卷 1-21页

作者： Yimin Zhang Tianmu Wang China Europe International Business School Shanghai China

This paper considers the cost structure, profitability and productivity of the Chinese textile industry and estimates the impacts of RMB appreciation on this industry. Using data for 1999-2006, we found that the industry has suffered from very low profit margins and returns on capital. Because input prices have been increasing, particularly since 2001, generating profits has become more difficult for the industry. Nevertheless, the industry achieved substantial productivity growth over the period examined. Although at an inadequate level the proJ^tability of the industry did show some signs of improvement. As long as this trend continues, the industry could obtain a decent level of profitability. Since 2005, however, the industry has faced a new challenge： the appreciation of the RMB. Based on 2006 data, we estimated the maximum rate of RMB appreciation that the industry would be able to sustain to be approximately 5percent a year.

关键词： Chinese textile industry productivity profitability RMB exchange rates

R&D,innovation and productivity relationships:Evidence from threshold panel model

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International Journal of Innovation Studies 2021年第3期5卷 113-126页

作者： Nesrine Hammar Yacine Belarbi Laboratory of Quantitative Economics Applied to Development National High School of Statistics and Applied Economy16000AlgiersAlgeria Department of Scientific and Technical Information and Documentation Research Center for Scientific and Technical Information16000AlgiersAlgeria Research Center for Applied Economics for Development 16000AlgiersAlgeria

This study investigates the nonlinear relationship between R&D expenditures,innovation,productivity,high-tech export products.Previous empirical research used linear standard structures to deal with these kinds of specifications,and it has shown that the linearity is frequently conditioned by other macroeconomic factors such as the level of development and the financial openness.Based on these arguments,our study investigates this question in econometric specification using panel smooth threshold regression methodology proposed by Gonzalez et al.in 2005.Our findings suggest that there is a threshold effect within the links between R&D expenditures,innovation,and productivity.The effect of R&D expenditures,innovation,productivity,and medium and high technology product exports is mixed.However,both positive and negative effects are found,depending on which innovation indicators are used or on which level of threshold variable is the most appropriate.The results advocate that the level of economic development can be considered as target indicators to conduct an innovation policy.

关键词： R&D expenditures Innovation productivity Medium-high technology exports Panel smooth threshold regression

Anti-dumping Shock and the productivity Response of Chinese Industries

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China & World Economy 2017年第2期25卷 107-126页

作者： Chunding Li Institute of World Economics and Politics Chinese Academy of Social Sciences China.

This paper provides a comprehensive analysis of the productivity effects of antidumping (AD) measures on Chinese industries. Industry-year panel data and generalized method of moments estimators are used in the empirical analysis. productivity indicators are calculated using data envelope analysis. The empirical results show that China's industrial total factor productivity has improved under the pressure of AD measures taken by developed countries, and the mechanism inspires technological progress but hurts technological efficiency. Developing countries' AD measures have no significant productivity effects on China's targeted industries, except for slightly positive effects on technological efficiency. These results indicate that China should pay more attention to technological innovation and take different counter-measures for different cases of AD measures.

关键词： antidumping data envelope analysis generalized method of moments productivity C23 F12 F13

Effect of acidic deposition on productivity of forest ecosystem and estimation of its economic losses in southern suburbs of Chongqing, China

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Journal of Environmental Sciences 1998年第2期10卷 83-88页

作者： Wu Gang Department of Systems Ecology, Research Center for Eco Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China Department of Systems Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

In accordance with principles and methods of ecology, the effects of acidic deposition on productivity and volume increment of masson pine and Cinnamomum campora forest which are widely distributed in southern suburbs of Chongqing, China were studied. Based on the field data and measurements, a multivariable stepwise regression model was established to analyze the effects of multiple environmental factors on the productivity of the forest ecosystems. This model was used to assess the volume and economic losses of these two forest ecosystems caused by acidic deposition. The result showed that, among the environmental factors, pH value of precipitation, soil depth, soil organic contents and slope are the dominant ones influencing the growth of masson pine forest. It was also shown that the acidic deposition has no clear relation to the growth of C.Campora forest, so development of such broad leaved forest is suitable in the area.

关键词： acidic deposition productivity volume increment economic loss.

The relationship between species richness and productivity in four typical grasslands of northern China

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Frontiers in Biology 2007年第3期2卷 318-323页

作者： MA Wenhong Department of Ecology College of Environmental SciencesCenter for Ecological Research&Educationand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871China School of Environment&Urban Study Peking University Shenzhen Graduate SchoolShenzhen 518055China

The relationship between plant species richness and primary productivity has long been a central topic in bio-diversity research.In this paper,we examine the relationship between species richness and productivity in four typical grasslands of Northern China at different spatial scales.At the community scale,a positive correlation was found for six of seven communities.A unimodal pattern was found only for one community(Stipa glareosa community),while at a large scale(vegetation type or landscape/region),the relationship was also found significantly positive.Species richness ranged from 4 to 35 species,and community aboveground producti-vity from 13 to 368 g·m^(-2)·a^(-1).The highest species richness and aboveground productivity were found in alpine meadow,followed by meadow steppe,typical steppe and desert steppe.

关键词： species richness productivity grasslands scale

Implications of population ageing for the Chinese productivity

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Economic and Political Studies 2016年第4期4卷 454-467页

作者： Yuwei Hu China Institute of Finance and Capital Markets BeijingChina

Since 2000 when China entered the‘ageing society’,the pace of ageing has speeded up.At the same time,traditional growth engines of the Chinese economy(i.***.export and investment)are losing momentum.Against this background,to what extent the expected demographic transformation would affect growth trajectory of the Chinese economy is of great interest.Among new growth engines,productivity has been receiving increasing attention among China’s top policy makers.In this paper,we try to identify both micro and macro effects of ageing on China’s productivity.In general,our research supports the hypothesis that more working experience and/or elder contributes to higher wage growth and total factor productivity,although with a reversed Ushaped pattern.

关键词： Population ageing productivity pension reform

City Size,Population Concentration and productivity: Evidence from China

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China & World Economy 2019年第1期27卷 110-131页

作者： Jie Shen Chunlai Chen Mengyu Yang Keyun Zhang Department of International Economies University of International RelationsChina Crawford School of Public Policy Australian National UniversityAustralia School of Economies Yunnan UniversityChina Institution of Regional and Urban Economics Renmin UniversityChina

This paper investigates the impact of China's city size and urban population concentration on city productivity by developing a distinctive index based on global nighttime light data.Using the panel data of 280 prefecture cities from 2004 to 2013 and employing dynamic system generalized method of moments and panel threshold model regression techniques,our results show that city size has a positive impact on city productivity;therefore,cities in China still have the potential to expand.While moderate urban population concentration can benefit city productivity,excessively concentrated urban population distribution may impede the growth of city productivity.We also find that the level of labor income significantly affects the impacts of urban agglomeration on labor productivity.Therefore,our results imply that city development policies should focus more on how to appropriately allocate economic activities and adjust population distribution in urban areas according to different stages of economic development.

关键词： city size nighttime light data population concentration productivity

Reconstruction of phytoplankton productivity and community structure in the South Yellow Sea

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China Geology 2019年第3期2卷 315-324页

作者： Xi Mei Ri-hui Li Xun-hua Zhang Zhong-bo Wang Yong Zhang Qingdao Institute of Marine Geology China Geological SurveyMinistry of Natural ResourcesQingdao 266071China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao266071China Key Laboratory of Marine Sedimentology and Environmental Geology First Institute of OceangraphyMinistry of Natural ResourcesQingdao 266061China

The sedimentary environment and ecological system in the South Yellow Sea (SYS) changed dramatically due to sea level change caused by glacial-interglacial cycles. The authors report the use of marine biomarkers (brassicasterol, dinosterol and C37 alkenones) and terrigenous biomarkers (C28+C30+C32 nalkanols) in core DLC70-3 from the SYS to reconstruct the variation in the phytoplankton productivity and community structure and possible mechanisms during the middle Pleistocene. The results show that the primary productivity and that of single algae presented a consistent trend for the whole core during the middle Pleistocene, which was high during interglacial periods and low during glacial periods, with the highest being in marine isotope stage (MIS) 5–9 and MIS 19–21. The main reason is that the Yellow Sea Warm Current (YSWC) carried much of high temperature, high salinity water into the SYS, causing upwelling and vertical mixing and stirring, which increased the nutrient supply in the photosynthetic layer. The phytoplankton community structure mainly showed an increase in the relative content of haptophytes in MIS 5–9 and MIS 19–21, while the relative content of diatoms and dinoflagellates decreased;there was no evidence for a haptophyte content in other stages. The results reveal a shift from a coccolitho-phoriddominated community during MIS 5 –9 and MIS 19 –21 to a diatom-dominated community during the other stages, mainly as a result of surface salinity variation, attributed to the invasion of the YSWC during high sea level periods.

关键词： Biomarker Phytoplankton productivity Phytoplankton community Ocean warm current Global climate change Marine geological survey engineering Yellow Sea China