121 research outputs found

    Adjustment and Optimization of the Cropping Systems Under Water Constraint

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    The water constraint on agricultural production receives growing concern with the increasingly sharp contradiction between demand and supply of water resources. How to mitigate and adapt to potential water constraint is one of the key issues for ensuring food security and achieving sustainable agriculture in the context of climate change. It has been suggested that adjustment and optimization of cropping systems could be an effective measure to improve water management and ensure food security. However, a knowledge gap still exists in how to quantify potential water constraint and how to select appropriate cropping systems. Here, we proposed a concept of water constraint risk and developed an approach for the evaluation of the water constraint risks for agricultural production by performing a case study in Daxing District, Beijing, China. The results show that, over the whole growth period, the order of the water constraint risks of crops from high to low was wheat, rice, broomcorn, foxtail millet, summer soybean, summer peanut, spring corn, and summer corn, and the order of the water constraint risks of the cropping systems from high to low was winter wheat-summer grain crops, rice, broomcorn, foxtail millet, and spring corn. Our results are consistent with the actual evolving process of cropping system. This indicates that our proposed method is practicable to adjust and optimize the cropping systems to mitigate and adapt to potential water risks. This study provides an insight into the adjustment and optimization of cropping systems under resource constraints

    Chronic larval exposure to thiacloprid impairs honeybee antennal selectivity, learning and memory performances

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    The use of agricultural neonicotinoid insecticides has sub-lethal chronic effects on bees that are more prevalent than acute toxicity. Among these insecticides, thiacloprid, a commonly used compound with low toxicity, has attracted significant attention due to its potential impact on the olfactory and learning abilities of honeybees. The effect of sub-lethal larval exposure to thiacloprid on the antennal activity of adult honeybees (Apis mellifera L.) is not yet fully understood. To address this knowledge gap, laboratory-based experiments were conducted in which honeybee larvae were administered thiacloprid (0.5 mg/L and 1.0 mg/L). Using electroantennography (EAG), the impacts of thiacloprid exposure on the antennal selectivity to common floral volatiles were evaluated. Additionally, the effects of sub-lethal exposure on odor-related learning and memory were also assessed. The results of this study reveal, for the first time, that sub-lethal larval exposure to thiacloprid decreased honeybee antenna EAG responses to floral scents, leading to increased olfactory selectivity in the high-dose (1.0 mg/L) group compared to the control group (0 mg/L vs. 1.0 mg/L: p = 0.042). The results also suggest that thiacloprid negatively affected odor-associated paired learning acquisition, as well as medium-term (1 h) (0 mg/L vs. 1.0 mg/L: p = 0.019) and long-term memory (24 h) (0 mg/L vs. 1.0 mg/L: p = 0.037) in adult honeybees. EAG amplitudes were dramatically reduced following R-linalool paired olfactory training (0 mg/L vs. 1.0 mg/L: p = 0.001; 0 mg/L vs. 0.5 mg/L: p = 0.027), while antennal activities only differed significantly in the control between paired and unpaired groups. Our results indicated that exposure to sub-lethal concentrations of thiacloprid may affect olfactory perception and learning and memory behaviors in honeybees. These findings have important implications for the safe use of agrochemicals in the environment

    Controllable synthesis of flake-like Al-doped ZnO nanostructures and its application in inverted organic solar cells

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    Flake-like Al-doped ZnO (AZO) nanostructures including dense AZO nanorods were obtained via a low-temperature (100°C) hydrothermal process. By doping and varying Al concentrations, the electrical conductivity (σ) and morphology of the AZO nanostructures can be readily controlled. The effect of σ and morphology of the AZO nanostructures on the performance of the inverted organic solar cells (IOSCs) was studied. It presents that the optimized power conversion efficiency of the AZO-based IOSCs is improved by approximately 58.7% compared with that of un-doped ZnO-based IOSCs. This is attributed to that the flake-like AZO nanostructures of high σ and tunable morphology not only provide a high-conduction pathway to facilitate electron transport but also lead to a large interfacial area for exciton dissociation and charge collection by electrodes

    Spontaneous doping of the basal plane of MoS2 single layers through oxygen substitution under ambient conditions

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    The chemical inertness of the defect-free basal plane confers environmental stability to MoS2 single-layers, but it also limits their chemical versatility and catalytic activity. The stability of the pristine MoS2 basal plane against oxidation under ambient conditions is a widely accepted assumption in the interpretation of various studies and applications. However, single-atom level structural investigations reported here reveal that oxygen atoms spontaneously incorporate into the basal plane of MoS2 single layers during ambient exposure. Our scanning tunneling microscopy investigations reveal a slow oxygen substitution reaction, upon which individual sulfur atoms are one by one replaced by oxygen, giving rise to solid solution type 2D MoS2-xOx crystals. O substitution sites present all over the basal plane act as single-atomic active reaction centers, substantially increasing the catalytic activity of the entire MoS2 basal plane for the electrochemical H2 evolution reaction.Comment: 6 pages, 5 figure

    Management controls in automotive international joint ventures involving Chinese parent companies

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    Key findings: • Flexibility in international joint ventures (JVS) is important and a shared but split control style is recommended. • Chinese partners used to have learning as their main objective in an IJV but this has been replaced by profit, growth and market share. • The most significant shifts in control between partners involve human resource management and research and development. • When foreign partners insist on adherence to their own management philosophy, culture clashes occur. • Negotiation is a part of daily life in the IJVs, and it occurs at both executive and managerial levels, depending upon the significance of the item

    Framing of healthcare performance in China’s public hospital field: An ethnographic study

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    This study adopts a multi-level framing perspective to investigate the conceptions of healthcare performance emerged and evolved in response to the dynamic institutional complexity following China’s healthcare system reforms. We investigate how public hospital performance has been framed and reframed at the organizational and field level following the marketization reform in the 1990s and the retreat from such reform in the 2000s in China. Through direct observation of meetings, archive data analysis and interviews with government officials, hospital managers and doctors, our ethnographic study sheds light on how the meanings of a specific performance term, ‘Ji Xiao’(literally ‘performance’ and ‘efficiency’), first emerged within the hospitals, evolved bottom-up and eventually acquired the taken-for-granted quality of institutions at the field level. The findings contribute to institutional theory in general and institutional research on performance measurement in particular by unpacking the bottom-up and top-down processes of institutionalization of a specific conception of performance

    The institutionalization of management accounting change: an observation across societal, organizational field, and organizational levels

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    The paper provides a holistic observation of the change process related to the quality control system in a Chinese SOE. Applying both framework of (Burns & Scapens, 2000) and (Dillard, Rigsby, & Goodman, 2004), the longitudinal case study observed the coupling between rules and routines at the first stage and loose coupling at the second stage in the case of adopting the Japanese style quality control system over nearly 20 years. The study further examined how such intra-organizational changes are shaped by dynamic institutions at societal level, such as market openness, government protection, and political constrains, as well as those at organizational field level, including IJV experience and trade union. The study contributes to management accounting change literature by presenting evidence on the interactions among those multi-level institutions. The findings shed light on how the policies at societal level can possibly affect intra-organizational change, which has policy implications for further SOE reforms in China and other transition economies
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