The unreasonable application of nitrogen fertilizer poses a threat to agricultural productivity and the environment protection in Northeast China.Therefore,accurately assessing crop nitrogen requirements and optimizin...The unreasonable application of nitrogen fertilizer poses a threat to agricultural productivity and the environment protection in Northeast China.Therefore,accurately assessing crop nitrogen requirements and optimizing fertilization are crucial for sustainable agricultural production.A three-year field experiment was conducted to evaluate the effects of planting density on the critical nitrogen concentration dilution curve(CNDC)for spring maize under drip irrigation and fertilization integration,incorporating two planting densities:D1(60,000 plants ha^(-1))and D2(90,000 plants ha^(-1))and six nitrogen levels:no nitrogen(N0),90(N90),180(N180),270(N270),360(N360),and 450(N450)kg ha^(-1).A Bayesian hierarchical model was used to develop CNDC models based on dry matter(DM)and leaf area index(LAI).The results revealed that the critical nitrogen concentration exhibited a power function relationship with both DM and LAI,while planting density had no significant impact on the CNDC parameters.Based on these findings,we propose unified CNDC equations for maize under drip irrigation and fertilization integration:Nc=4.505DM-0.384(based on DM)and Nc=3.793LAI-0.327(based on LAI).Additionally,the nitrogen nutrition index(NNI),derived from the CNDC,increased with higher nitrogen application rates.The nitrogen nutrition index(NNI)approached 1 with a nitrogen application rate of 180 kg ha^(-1)under the D1 planting density,while it reached 1 at 270 kg ha^(-1)under the D2 planting density.The relationship between NNI and relative yield(RY)followed a“linear+plateau”model,with maximum RY observed when the NNI approached 1.Thus,under the condition of drip irrigation and fertilization integration in Northeast China’s spring maize production,the optimal nitrogen application rates for achieving the highest yields were 180 kg ha^(-1)at a planting density of 60,000 plants ha^(-1),and 270 kg ha^(-1)at a density of 90,000 plants ha^(-1).The CNDC and NNI models developed in this study are valuable tools for diagnosing nitrogen nutrition and guiding precise fertilization practices in maize production under integrated drip irrigation and fertilization systems in Northeast China.展开更多
Recently, with increasing improvements in the penetration of wind power and photovoltaic power in the world, probabilistic small signal stability analysis(PSSSA) of a power system consisting of multiple types of renew...Recently, with increasing improvements in the penetration of wind power and photovoltaic power in the world, probabilistic small signal stability analysis(PSSSA) of a power system consisting of multiple types of renewable energy has become a key problem. To address this problem, this study proposes a probabilistic collocation method(PCM)-based PSSSA for a power system consisting of wind farms and photovoltaic farms. Compared with the conventional Monte Carlo method, the proposed method meets the accuracy and precision requirements and greatly reduces the computation; therefore, it is suitable for the PSSSA of this power system. Case studies are conducted based on a 4-machine 2-area and New England systems, respectively. The simulation results show that, by reducing synchronous generator output to improve the penetration of renewable energy, the probabilistic small signal stability(PSSS) of the system is enhanced. Conversely, by removing part of the synchronous generators to improve the penetration of renewable energy, the PSSS of the system may be either enhanced or deteriorated.展开更多
Farmers in China often use nitrogen(N)fertilizers to ensure adequate crop growth.However,inappropriate applications have increased the risk of environmental pollution,lowered maize yields,and reduced profits for farme...Farmers in China often use nitrogen(N)fertilizers to ensure adequate crop growth.However,inappropriate applications have increased the risk of environmental pollution,lowered maize yields,and reduced profits for farmers.Proper N fertilizer management is crucial for improving yield and nitrogen use efficiency(NUE).This study conducted a three-year experiment involving nine N treatments(0,45,90,135,180,225,270,315,and 360 kg ha^(-1))on a field under nitrogen fertilizer precision management(NFPM)in Northeast China.The results were compared with studies published within the past decade that analyzed yield and dry matter(DM)content under two management practices in Northeast China:conventional nitrogen fertilization management(CNFM)and water-saving fertilization management(WSFM).The findings reveal that maize yield increases with rising N application rates up to 270 kg ha^(-1),after which yield decreases.The kernel number(KN)and kernel weight(KW)of maize grown under NFPM were 13.7 and 14.7%higher than those grown under WSFM,respectively.Furthermore,they surpassed crops grown under CNFM by 38.4 and 21.2%,respectively.The maximum total yield of the NFPM treatment was 41.8 and 78.8%higher than under WSFM and CNFM,respectively.In addition,compared with CNFM and WSFM,NFPM significantly increased NUE across the various N-level treatments.Optimizing nitrogen management can help farmers to achieve higher yields and promote sustainable agricultural development.展开更多
β-catenin is a multifunctional protein that plays crucial roles in embryonic development,physiological homeostasis,and a wide variety of human cancers.Previously,we showed that in vivo targeted ablation ofβ-catenin ...β-catenin is a multifunctional protein that plays crucial roles in embryonic development,physiological homeostasis,and a wide variety of human cancers.Previously,we showed that in vivo targeted ablation ofβ-catenin in melanoma-associated fibroblasts after melanoma formation significantly suppressed tumor growth.However,when the expression ofβ-catenin was ablated in melanoma-associated fibroblasts before tumor initiation,melanoma development was surprisingly accelerated.How stromalβ-catenin deficiency leads to opposite biological effects in melanoma progression is not completely understood.Here,we report thatβ-catenin is indispensable for the activation of primary human stromal fibroblasts and the mediation of fibroblast-melanoma cell interactions.Using coimmunoprecipitation and proximity ligation assays,we identified Yes-associated protein(YAP)as an importantβ-catenin-interacting partner in stromal fibroblasts.YAP is highly expressed in the nuclei of cancer-associated fibroblasts(CAFs)in both human and murine melanomas.Mechanistic investigation revealed that YAP nuclear translocation is significantly modulated by Wnt/β-catenin activity in fibroblasts.Blocking Wnt/β-catenin signaling in stromal fibroblasts inhibited YAP nuclear translocation.In the absence of YAP,the ability of stromal fibroblasts to remodel the extracellular matrix(ECM)was inhibited,which is consistent with the phenotype observed in cells withβ-catenin deficiency.Further studies showed that the expression of ECM proteins and enzymes required for remodeling the ECM was suppressed in stromal fibroblasts after YAP ablation.Collectively,our data provide a new paradigm in which theβ-catenin-YAP signaling axis regulates the activation and tumor-promoting function of stromal fibroblasts.展开更多
Highlights This study explores the experiences of project-based learning(PBL)experimentation in Chinese high schools,especilly the feedback that Chinese students have for better practicing PBLinChina.We conducted a ca...Highlights This study explores the experiences of project-based learning(PBL)experimentation in Chinese high schools,especilly the feedback that Chinese students have for better practicing PBLinChina.We conducted a case study at two Chinese high schools in an intermediate city,Suzhou,which started their first PBL practice.The two high schools were chosen because of their unique initiative to mix visually impaired students(VIS)and ordinary students in a PBL course,which focuses on"designing accessible garbage bins for VIs."Interviews and observations were conducted.All data are anonymized.After two rounds of thematic sorting and coding of the qualitative data,we found that the PBL course helped students develop two aspects of the civic participation dimension of core competence:social responsibility and problem-solving.Students learned to empathize with VIS to understand their needs and to build a more feasible and usable garbage bin.This study provides instructional recommendations in terms of how to better utilize the pedagogy of PBL in Chinese K-12 schools,particularly to support teachers to facilitate students'development of core competence and learning of inclusion,social responsibility,and sustainability by using the PBL technique.展开更多
基金supported by the grants from National Key Research and Development Program of China(2023YFD2303300)China Agriculture Research System(CARS-02-15)the Agricultural Science and Technology Innovation Program(CAAS-ZDRW202004).
文摘The unreasonable application of nitrogen fertilizer poses a threat to agricultural productivity and the environment protection in Northeast China.Therefore,accurately assessing crop nitrogen requirements and optimizing fertilization are crucial for sustainable agricultural production.A three-year field experiment was conducted to evaluate the effects of planting density on the critical nitrogen concentration dilution curve(CNDC)for spring maize under drip irrigation and fertilization integration,incorporating two planting densities:D1(60,000 plants ha^(-1))and D2(90,000 plants ha^(-1))and six nitrogen levels:no nitrogen(N0),90(N90),180(N180),270(N270),360(N360),and 450(N450)kg ha^(-1).A Bayesian hierarchical model was used to develop CNDC models based on dry matter(DM)and leaf area index(LAI).The results revealed that the critical nitrogen concentration exhibited a power function relationship with both DM and LAI,while planting density had no significant impact on the CNDC parameters.Based on these findings,we propose unified CNDC equations for maize under drip irrigation and fertilization integration:Nc=4.505DM-0.384(based on DM)and Nc=3.793LAI-0.327(based on LAI).Additionally,the nitrogen nutrition index(NNI),derived from the CNDC,increased with higher nitrogen application rates.The nitrogen nutrition index(NNI)approached 1 with a nitrogen application rate of 180 kg ha^(-1)under the D1 planting density,while it reached 1 at 270 kg ha^(-1)under the D2 planting density.The relationship between NNI and relative yield(RY)followed a“linear+plateau”model,with maximum RY observed when the NNI approached 1.Thus,under the condition of drip irrigation and fertilization integration in Northeast China’s spring maize production,the optimal nitrogen application rates for achieving the highest yields were 180 kg ha^(-1)at a planting density of 60,000 plants ha^(-1),and 270 kg ha^(-1)at a density of 90,000 plants ha^(-1).The CNDC and NNI models developed in this study are valuable tools for diagnosing nitrogen nutrition and guiding precise fertilization practices in maize production under integrated drip irrigation and fertilization systems in Northeast China.
基金supported by the National Natural Science Foundation of China (NSFC) (No. 51577075)
文摘Recently, with increasing improvements in the penetration of wind power and photovoltaic power in the world, probabilistic small signal stability analysis(PSSSA) of a power system consisting of multiple types of renewable energy has become a key problem. To address this problem, this study proposes a probabilistic collocation method(PCM)-based PSSSA for a power system consisting of wind farms and photovoltaic farms. Compared with the conventional Monte Carlo method, the proposed method meets the accuracy and precision requirements and greatly reduces the computation; therefore, it is suitable for the PSSSA of this power system. Case studies are conducted based on a 4-machine 2-area and New England systems, respectively. The simulation results show that, by reducing synchronous generator output to improve the penetration of renewable energy, the probabilistic small signal stability(PSSS) of the system is enhanced. Conversely, by removing part of the synchronous generators to improve the penetration of renewable energy, the PSSS of the system may be either enhanced or deteriorated.
基金research support from the National Natural Science Foundation of China(M2142005)the Inner Mongolia Science and Technology Major Project,China(2021ZD0003)。
文摘Farmers in China often use nitrogen(N)fertilizers to ensure adequate crop growth.However,inappropriate applications have increased the risk of environmental pollution,lowered maize yields,and reduced profits for farmers.Proper N fertilizer management is crucial for improving yield and nitrogen use efficiency(NUE).This study conducted a three-year experiment involving nine N treatments(0,45,90,135,180,225,270,315,and 360 kg ha^(-1))on a field under nitrogen fertilizer precision management(NFPM)in Northeast China.The results were compared with studies published within the past decade that analyzed yield and dry matter(DM)content under two management practices in Northeast China:conventional nitrogen fertilization management(CNFM)and water-saving fertilization management(WSFM).The findings reveal that maize yield increases with rising N application rates up to 270 kg ha^(-1),after which yield decreases.The kernel number(KN)and kernel weight(KW)of maize grown under NFPM were 13.7 and 14.7%higher than those grown under WSFM,respectively.Furthermore,they surpassed crops grown under CNFM by 38.4 and 21.2%,respectively.The maximum total yield of the NFPM treatment was 41.8 and 78.8%higher than under WSFM and CNFM,respectively.In addition,compared with CNFM and WSFM,NFPM significantly increased NUE across the various N-level treatments.Optimizing nitrogen management can help farmers to achieve higher yields and promote sustainable agricultural development.
基金This work was supported by NIH R15CA228014(YZ),the Cincinnati Cancer Center-Mentor-Mentee Award(YZ),the Harry J Lloyd Trust Research Award(Y.Z.)and the CCTST Pilot Translational Research&Innovative Core Grant(Y.Z.).
文摘β-catenin is a multifunctional protein that plays crucial roles in embryonic development,physiological homeostasis,and a wide variety of human cancers.Previously,we showed that in vivo targeted ablation ofβ-catenin in melanoma-associated fibroblasts after melanoma formation significantly suppressed tumor growth.However,when the expression ofβ-catenin was ablated in melanoma-associated fibroblasts before tumor initiation,melanoma development was surprisingly accelerated.How stromalβ-catenin deficiency leads to opposite biological effects in melanoma progression is not completely understood.Here,we report thatβ-catenin is indispensable for the activation of primary human stromal fibroblasts and the mediation of fibroblast-melanoma cell interactions.Using coimmunoprecipitation and proximity ligation assays,we identified Yes-associated protein(YAP)as an importantβ-catenin-interacting partner in stromal fibroblasts.YAP is highly expressed in the nuclei of cancer-associated fibroblasts(CAFs)in both human and murine melanomas.Mechanistic investigation revealed that YAP nuclear translocation is significantly modulated by Wnt/β-catenin activity in fibroblasts.Blocking Wnt/β-catenin signaling in stromal fibroblasts inhibited YAP nuclear translocation.In the absence of YAP,the ability of stromal fibroblasts to remodel the extracellular matrix(ECM)was inhibited,which is consistent with the phenotype observed in cells withβ-catenin deficiency.Further studies showed that the expression of ECM proteins and enzymes required for remodeling the ECM was suppressed in stromal fibroblasts after YAP ablation.Collectively,our data provide a new paradigm in which theβ-catenin-YAP signaling axis regulates the activation and tumor-promoting function of stromal fibroblasts.
基金High school students,inclusive education,innovative education,project-based learning。
文摘Highlights This study explores the experiences of project-based learning(PBL)experimentation in Chinese high schools,especilly the feedback that Chinese students have for better practicing PBLinChina.We conducted a case study at two Chinese high schools in an intermediate city,Suzhou,which started their first PBL practice.The two high schools were chosen because of their unique initiative to mix visually impaired students(VIS)and ordinary students in a PBL course,which focuses on"designing accessible garbage bins for VIs."Interviews and observations were conducted.All data are anonymized.After two rounds of thematic sorting and coding of the qualitative data,we found that the PBL course helped students develop two aspects of the civic participation dimension of core competence:social responsibility and problem-solving.Students learned to empathize with VIS to understand their needs and to build a more feasible and usable garbage bin.This study provides instructional recommendations in terms of how to better utilize the pedagogy of PBL in Chinese K-12 schools,particularly to support teachers to facilitate students'development of core competence and learning of inclusion,social responsibility,and sustainability by using the PBL technique.
