[Objective] Application of P and K was not reasonable in southwest rice producing area, with no effective method for guiding application of P and K. This study aimed to conduct experiments with the same N application ...[Objective] Application of P and K was not reasonable in southwest rice producing area, with no effective method for guiding application of P and K. This study aimed to conduct experiments with the same N application and different P and K application in different ecological points, to explore a scientific and efficient management method of P and K nutrients and provide guidance for application of P and K in rice production. [Method] Hybrid rice Chuanxiang9838 was used as experimental material to study the relationship among application amount of P and K, utilization rates of P and K, rice yield and rice quality in seven ecological points of four provinces （municipalities） including Sichuan, Chongqing, Yunnan and Guizhou. The application amount per hectare of P was 37.5, 75, 112.5 and 150 kg, respectively; the application amount per hectare of K was 45, 135 and 180 kg, respectively. A total of 10 treatments were set for split-plot design with three replications. [Result] Yield of Chuanxiang9838 significantly varied in different experimental locations and under different levels of P and K, interaction of ecological point and different P and K treatments varied significantly. Yield had reached the maximum in ecological point of Yunnan Binchuan and in treatment with application of N 150 kg P 75 kg K 90 kg. Efficient utilization rates of P and K varied in each ecological point, efficient application amount of P and K in Sichuan Dongpo, Sichuan Luxian, Guizhou Xiaohe and Chongqing Yongchuan was the same, while that in Sichuan Guanghan, Sichuan Zhongjiang and Yunnan Binchuan was different. The main objective of high-yield rice production was to increase the number of effective panicles per hectare and seed setting rate. Rice quality was clustered into 2 categories by locations and 6 categories by treatments. [Conclusion] Prediction models of efficient application of P and K in rice production were established, which provided guidance for high-yield rice production and rational and efficient utilization of P and K in southwest rice area.展开更多
[Objective] The behavior of eating, drinking, defecating and peeing of 1 500 pigs in a large-scale microbial fermentation bed-equipped piggery was observed. We hoped to find some simple indicators that could reflect t...[Objective] The behavior of eating, drinking, defecating and peeing of 1 500 pigs in a large-scale microbial fermentation bed-equipped piggery was observed. We hoped to find some simple indicators that could reflect the health status of swinery and to provide experience for the swinery performance management in large-scale microbial fermentation bed-equipped piggery. [Method] The body weight （BW）, daily BW gain, feed intake and other indicators of different-day-old pigs were recorded in details. Based on the recorded data, the models between BW, BW gain, average daily feed intake and feed/gain ratio and growth days （d） were established. In addition, the incidences of pox-like macula （dermatitis）, diarrhea （gastrointestinal disease）, cough （respiratory disease）, stiff pig （malnutrition）, conjunctivitis （eye disease） and foot inflection （trauma） among fattening pigs were also investigated. [Result] The BW range, average BW, daily BW gain, breeding days, daily feed intake range, average daily feed intake, staged feed intake, accumulated feed intake, feed/gain ratio and accumulated feed/gain ratio of different-day-old pigs were studied, respectively. Four dynamic models were established for the growth of pigs： （1） the BW （y）-age （x） mod- el： y=0.758 9x-19.883 （3=0.993 7）; （2） the BW gain （y）-age （x） model： y=1.039 5x05051 （F=0.885 4）; （3） the average daily feed intake （y）-age （x） model： y=0.023 5x-0.334 3 （F=0.991 7）; （4） the feed/gain ratio （y）-age （x） model： y=0.022x＋0.427 8 （P=0.988 5）. Based on these models, the corresponding theoretical growth value of pigs at different growth stage could be predicted. The main diseases occurred among the swinery in the large-scale microbial fermentation bed piggery included pox-like macula （dermatitis）, diarrhea （gastrointestinal disease）, cough （respiratory disease）, stiff pig （mal- nutrition）, conjunctivitis （eye disease） and foot inflection （trauma）. The deadly infec- tious diseases had been not found among the pigs. [Conclusion] When the actual BW, BW gain, average daily feed intake and feed/gain ratio were all lower than the theoretical values predicted by the models, the management should be enhanced. The average daily feed intake of 60 to 65-day-old pigs was lower than the theoretic value, indicating that the pigs could not adapt nicely to the fermentation bed at the very early stage. When the pigs grew up to 70 to 75 d old, the average daily feed intake was higher than the theoretical value, indicating that the pigs had adapted to the fermentation bed. In particularly, average daily feed intake of 75-day-old pigs was higher than the theoretical value by 21%. It was suggested the fermentation bed was conducive to the growth of pigs. Considering the occurrence of diseases among pigs, the overall incidence was relatively low. The incidence of each disease was all lower than 10% with little difficulty in treating. If the management of mattress was strength- ened, such as paying attention to feeding and keeping water clean, many diseases could heal by themselves.展开更多
Transitions of normal universities in our country are inexorable trends with the development of the times. In this process, normal universities should actively reform models of talents cultivation, establish teachers...Transitions of normal universities in our country are inexorable trends with the development of the times. In this process, normal universities should actively reform models of talents cultivation, establish teachers＇ profession with distinguishing features, construct new strategies of talents cultivation so as to improve all-round capacities of normal universities in running schools.展开更多
This paper focuses on the training modes of interdisciplinary and application-oriented talents of business English and the constructions of curriculum. In the light of our socialist market-oriented economy characteris...This paper focuses on the training modes of interdisciplinary and application-oriented talents of business English and the constructions of curriculum. In the light of our socialist market-oriented economy characteristics, the discussion proceeds, in theory and practice, by putting forward a relatively profound approach according to the trend in the demands for business English talents and to the operational patterns of business English discipline, with some suggestions about the training modes of interdisciplinary and application-oriented talents and the construction of curriculum.展开更多
The nutrient cycling model NuCM is one of the most detailed models for simulating processes that influence nutrient cycling in forest ecosystems. A field study was conducted at Tieshanping, a Masson pine (Pinus masson...The nutrient cycling model NuCM is one of the most detailed models for simulating processes that influence nutrient cycling in forest ecosystems. A field study was conducted at Tieshanping, a Masson pine (Pinus massoniana Lamb.) forest site, in Chongqing, China, to monitor the impacts of acidic precipitation on nutrient cycling. NuCM simulations were compared with observed data from the study site. The model produced an approximate fit with the observed data. It simulated the mean annual soil solution concentrations in the two simulation years, whereas it sometimes failed to reproduce seasonal variation. Even though some of the parameters required by model running were measured in the field, some others were still highly uncertain and the uncertainties were analyzed. Some of the uncertain parameters necessary for model running should be measured and calibrated to produce a better fit between modeled results and field data.展开更多
Anchovy （Engraulis aponicus）, a small pelagic fish and food of other economic fishes, is a key species in the Yellow Sea ecosystem. Understanding the mechanisms of its recruitment and biomass variation is important ...Anchovy （Engraulis aponicus）, a small pelagic fish and food of other economic fishes, is a key species in the Yellow Sea ecosystem. Understanding the mechanisms of its recruitment and biomass variation is important for the prediction and management of fishery resources. Coupled with a hydrodynamic model （POM） and a lower trophic level ecosystem model （NEMURO）, an individual-based model of anchovy is developed to study the influence of physical environment on anchovy＇s biomass variation, Seasonal variations of circulation, water temperature and mix-layer depth from POM are used as external forcing for NEMURO and the anchovy model. Biomasses of large zooplankton and predatory zooplankton which anchovy feeds on are output from NEMURO and are controlled by the consumption of anchovy on them. Survival fitness theory related to temperature and food is used to determine the swimming action of anchovy in the model. The simulation results agree well with observations and elucidate the influence of temperature in over-wintering migration and food in feeding migration.展开更多
Applied Immobilized algae bacteria (ABI) to remove ammonia of freshwater aquaculture wastewater. Temperature (T),PH,light intensity (I),dissolved oxygen (DO) and filling rate five factors plays important role in the p...Applied Immobilized algae bacteria (ABI) to remove ammonia of freshwater aquaculture wastewater. Temperature (T),PH,light intensity (I),dissolved oxygen (DO) and filling rate five factors plays important role in the process of ammonia nitrogen removal ,related data between ammonia removal and five factors was received through multi-factor orthogonal test,and established relations model between the five factor and nitrogen removal. The results show that five-factors had significant effect on AR,and the best combinations for removing AR was temperature 30 ℃,pH=7.0,light intensity 6 000 lux,dissolved oxygen 5.0 mg/L and the fill rate 10%. According to the experimental data,equation model was proposed and coefficient of determination R2 =0.864 8,P<0.05. Samples T-test was done between the model predictions and the actual measured values.Test results showed that the significant difference of overall mean value sig. (2-tailed) was 0.978 (P>0.05),it Shows that had no significant difference between model predictions and the actual measured value,and model had a high degree of fitting.展开更多
AIM： To study the effect of early intrajejunal nutrition on enzyme-protein synthesis and secretion during acute pancreatitis. METHODS： Fifteen dogs were randomly divided into parenteral nutrition （n = 7） and early...AIM： To study the effect of early intrajejunal nutrition on enzyme-protein synthesis and secretion during acute pancreatitis. METHODS： Fifteen dogs were randomly divided into parenteral nutrition （n = 7） and early intrajejunal nutrition groups （n = 8）. An acute pancreatitis model was induced by injecting 5% sodium taurocholate and trypsin into the pancreas via the pancreatic duct. Intrajejunal nutrition was delivered with a catheter via a jejunostomy tube after the model was established for 24 h. On d 1 and 7 and at the beginning of nutritional support, radioactive tracing and electron microscopes were used to evaluate the enzyme-protein synthesis in acinar cells, the subcellular fractionation and the change in zymogen granules after 1.85 × 10^6 Bq L-3H phenylalanine was infused at 30, 60, 120, and 180 min. RESULTS： The 3H radioactivity in pancreatic acinar cells reached its peak level at 60 min, and the contents in the early intrajejunal nutrition group were higher than those in the parenteral nutrition group, which were then decreased. The mean number and area of zymogen granules did not show any significant statistical difference in both groups on d i or on d 7 （P 〉 0.05）. CONCLUSION： Early intrajejunal nutrition might be effective in dogs with acute pancreatitis.展开更多
On the basis of the soil environment investigation in Da＇an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter （SOM）, total N （TN...On the basis of the soil environment investigation in Da＇an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter （SOM）, total N （TN）, total P （TP）, total K （TK）, available N （AN）, available P （AP） and available K （AK） were chosen as the evaluation factors. A regional soil nutrient evaluation model was developed based on the matter-element model. The results show that the soil samples with nutrient grade Ⅱ-Ⅴ respectively account for 10%, 30%, 32.5% and 27.5%, and those with grade Ⅳ and Ⅴ account for 60% in all samples. The relationship between soil nutrients and land types indicates that the nutrients of farmland are relatively good, with 41.7% of soil samples with the nutrient grade Ⅳ and Ⅴ. The nutrients of saline-alkali land and sandy land are the worst, with 100% of soil samples with the nutrient grade IV and V. And the ratios of soil samples grade IV and V in grassland and wasteland are respectively 62.5 % and 54.55%. Generally speaking, the soil nutrients status in Da＇an City is poor, 60% of soil samples are in poor and extremely poor conditions, indicating that the soil has been severely eroded. Being a relatively superior evaluation method with more accurate resuits and spatial distribution consistency, matter-element analysis is more suitable for regional soil nutrient evaluation than previous models.展开更多
Soil macronutrients(i.e. nitrogen(N), phosphorus(P), and potassium(K)) are important soils components and knowing the spatial distribution of these parameters are necessary at precision agriculture. The purpose of thi...Soil macronutrients(i.e. nitrogen(N), phosphorus(P), and potassium(K)) are important soils components and knowing the spatial distribution of these parameters are necessary at precision agriculture. The purpose of this study was to evaluate the feasibility of different methods such as artificial neural networks(ANN) and two geostatistical methods(geographically weighted regression(GWR) and cokriging(CK)) to estimate N, P and K contents. For this purpose, soil samples were taken from topsoil(0–30 cm) at 106 points and analyzed for their chemical and physical parameters. These data were divided into calibration(n = 84) and validation(n = 22). Chemical and physical variables including clay, p H and organic carbon(OC) were used as auxiliary soil variables to estimate the N, P and K contents. Results showed that the ANN model(with coefficient of determination R^2 = 0.922 and root mean square error RMSE = 0.0079%) was more accurate compared to the CK model(with R^2 = 0.612 and RMSE = 0.0094%), and the GWR model(with R^2 = 0.872 and RMSE = 0.0089%) to estimate the N variable. The ANN model estimated the P with the RMSE of 3.630 ppm, which was respectively 28.93% and 20.00% less than the RMSE of 4.680 ppm and 4.357 ppm from the CK and GWR models. The estimated K by CK, GWR and ANN models have the RMSE of 76.794 ppm, 75.790 ppm and 52.484 ppm. Results indicated that the performance of the CK model for estimation of macro nutrients(N, P and K) was slightly lower than the GWR model. Also, the accuracy of the ANN model was higher than CK and GWR models, which proved to be more effective and reliable methods for estimating macro nutrients.展开更多
Microglial activation plays an important role in a panel of neurological disorders such as multiple sclerosis(MS) and Parkinson's disease(PD),and is a key target for developing therapeutic strategies for these dis...Microglial activation plays an important role in a panel of neurological disorders such as multiple sclerosis(MS) and Parkinson's disease(PD),and is a key target for developing therapeutic strategies for these diseases.Ketogenic diet (KD),which is able to inhibit microglial activation in substantia nigra pars compacta of mice,has been shown effective in a mouse model of PD,possibly through increasing D-β-hydroxybutyrate(D-β-HB),a major component of ketone bodies.To verify this,we developed an in vitro model of microglia activation with a microglia line,BV-2,and investigated how D-β-HB have an effect on the LPS-stimulated BV-2 cells.We found D-β-HB is able to recover the cell viability,and inhibit the production of inflammatory mediators and cytokines such as ROS,nitrite,IL-1β,TNF-α,and IL-6,which otherwise were increased in LPS-stimulated BV-2 cells.We conclude that the LPS induced BV-2 cells activation is a valid in vitro model of microglia activation.D-β-HB is able to suppress the activation of BV-2 cells, which might account for one of the possible reasons of KD therapy on the PD model.展开更多
基金Supported by Project of Rice Industry Technology System ConstructionGrain Production Technology Engineering Project200903002 Project~~
文摘[Objective] Application of P and K was not reasonable in southwest rice producing area, with no effective method for guiding application of P and K. This study aimed to conduct experiments with the same N application and different P and K application in different ecological points, to explore a scientific and efficient management method of P and K nutrients and provide guidance for application of P and K in rice production. [Method] Hybrid rice Chuanxiang9838 was used as experimental material to study the relationship among application amount of P and K, utilization rates of P and K, rice yield and rice quality in seven ecological points of four provinces （municipalities） including Sichuan, Chongqing, Yunnan and Guizhou. The application amount per hectare of P was 37.5, 75, 112.5 and 150 kg, respectively; the application amount per hectare of K was 45, 135 and 180 kg, respectively. A total of 10 treatments were set for split-plot design with three replications. [Result] Yield of Chuanxiang9838 significantly varied in different experimental locations and under different levels of P and K, interaction of ecological point and different P and K treatments varied significantly. Yield had reached the maximum in ecological point of Yunnan Binchuan and in treatment with application of N 150 kg P 75 kg K 90 kg. Efficient utilization rates of P and K varied in each ecological point, efficient application amount of P and K in Sichuan Dongpo, Sichuan Luxian, Guizhou Xiaohe and Chongqing Yongchuan was the same, while that in Sichuan Guanghan, Sichuan Zhongjiang and Yunnan Binchuan was different. The main objective of high-yield rice production was to increase the number of effective panicles per hectare and seed setting rate. Rice quality was clustered into 2 categories by locations and 6 categories by treatments. [Conclusion] Prediction models of efficient application of P and K in rice production were established, which provided guidance for high-yield rice production and rational and efficient utilization of P and K in southwest rice area.
基金Supported by International Science and Technology Cooperation Project of China(2012DFA31120)Special Fund for Agro-scientific Research in the Public Interest(201303094)National Key Technology Research and Development Program(2012BAD14B15)~~
文摘[Objective] The behavior of eating, drinking, defecating and peeing of 1 500 pigs in a large-scale microbial fermentation bed-equipped piggery was observed. We hoped to find some simple indicators that could reflect the health status of swinery and to provide experience for the swinery performance management in large-scale microbial fermentation bed-equipped piggery. [Method] The body weight （BW）, daily BW gain, feed intake and other indicators of different-day-old pigs were recorded in details. Based on the recorded data, the models between BW, BW gain, average daily feed intake and feed/gain ratio and growth days （d） were established. In addition, the incidences of pox-like macula （dermatitis）, diarrhea （gastrointestinal disease）, cough （respiratory disease）, stiff pig （malnutrition）, conjunctivitis （eye disease） and foot inflection （trauma） among fattening pigs were also investigated. [Result] The BW range, average BW, daily BW gain, breeding days, daily feed intake range, average daily feed intake, staged feed intake, accumulated feed intake, feed/gain ratio and accumulated feed/gain ratio of different-day-old pigs were studied, respectively. Four dynamic models were established for the growth of pigs： （1） the BW （y）-age （x） mod- el： y=0.758 9x-19.883 （3=0.993 7）; （2） the BW gain （y）-age （x） model： y=1.039 5x05051 （F=0.885 4）; （3） the average daily feed intake （y）-age （x） model： y=0.023 5x-0.334 3 （F=0.991 7）; （4） the feed/gain ratio （y）-age （x） model： y=0.022x＋0.427 8 （P=0.988 5）. Based on these models, the corresponding theoretical growth value of pigs at different growth stage could be predicted. The main diseases occurred among the swinery in the large-scale microbial fermentation bed piggery included pox-like macula （dermatitis）, diarrhea （gastrointestinal disease）, cough （respiratory disease）, stiff pig （mal- nutrition）, conjunctivitis （eye disease） and foot inflection （trauma）. The deadly infec- tious diseases had been not found among the pigs. [Conclusion] When the actual BW, BW gain, average daily feed intake and feed/gain ratio were all lower than the theoretical values predicted by the models, the management should be enhanced. The average daily feed intake of 60 to 65-day-old pigs was lower than the theoretic value, indicating that the pigs could not adapt nicely to the fermentation bed at the very early stage. When the pigs grew up to 70 to 75 d old, the average daily feed intake was higher than the theoretical value, indicating that the pigs had adapted to the fermentation bed. In particularly, average daily feed intake of 75-day-old pigs was higher than the theoretical value by 21%. It was suggested the fermentation bed was conducive to the growth of pigs. Considering the occurrence of diseases among pigs, the overall incidence was relatively low. The incidence of each disease was all lower than 10% with little difficulty in treating. If the management of mattress was strength- ened, such as paying attention to feeding and keeping water clean, many diseases could heal by themselves.
文摘Transitions of normal universities in our country are inexorable trends with the development of the times. In this process, normal universities should actively reform models of talents cultivation, establish teachers＇ profession with distinguishing features, construct new strategies of talents cultivation so as to improve all-round capacities of normal universities in running schools.
文摘This paper focuses on the training modes of interdisciplinary and application-oriented talents of business English and the constructions of curriculum. In the light of our socialist market-oriented economy characteristics, the discussion proceeds, in theory and practice, by putting forward a relatively profound approach according to the trend in the demands for business English talents and to the operational patterns of business English discipline, with some suggestions about the training modes of interdisciplinary and application-oriented talents and the construction of curriculum.
基金the Chinese-Norwegian Cooperation Project Integrated Monitoring Program on Acidification of Chinese Terrestrial Systems (IMPACTS)the Chinese Academy of Forestry (No.CAFYBB200700X)
文摘The nutrient cycling model NuCM is one of the most detailed models for simulating processes that influence nutrient cycling in forest ecosystems. A field study was conducted at Tieshanping, a Masson pine (Pinus massoniana Lamb.) forest site, in Chongqing, China, to monitor the impacts of acidic precipitation on nutrient cycling. NuCM simulations were compared with observed data from the study site. The model produced an approximate fit with the observed data. It simulated the mean annual soil solution concentrations in the two simulation years, whereas it sometimes failed to reproduce seasonal variation. Even though some of the parameters required by model running were measured in the field, some others were still highly uncertain and the uncertainties were analyzed. Some of the uncertain parameters necessary for model running should be measured and calibrated to produce a better fit between modeled results and field data.
基金supported by the National Natural Science Foundation of China (Grant No. 40830854)the National Basic Research Program of China (Grant No.2011CB403606)
文摘Anchovy （Engraulis aponicus）, a small pelagic fish and food of other economic fishes, is a key species in the Yellow Sea ecosystem. Understanding the mechanisms of its recruitment and biomass variation is important for the prediction and management of fishery resources. Coupled with a hydrodynamic model （POM） and a lower trophic level ecosystem model （NEMURO）, an individual-based model of anchovy is developed to study the influence of physical environment on anchovy＇s biomass variation, Seasonal variations of circulation, water temperature and mix-layer depth from POM are used as external forcing for NEMURO and the anchovy model. Biomasses of large zooplankton and predatory zooplankton which anchovy feeds on are output from NEMURO and are controlled by the consumption of anchovy on them. Survival fitness theory related to temperature and food is used to determine the swimming action of anchovy in the model. The simulation results agree well with observations and elucidate the influence of temperature in over-wintering migration and food in feeding migration.
基金Supported by the National Natural Science Foundation of China(No.30972260)~~
文摘Applied Immobilized algae bacteria (ABI) to remove ammonia of freshwater aquaculture wastewater. Temperature (T),PH,light intensity (I),dissolved oxygen (DO) and filling rate five factors plays important role in the process of ammonia nitrogen removal ,related data between ammonia removal and five factors was received through multi-factor orthogonal test,and established relations model between the five factor and nitrogen removal. The results show that five-factors had significant effect on AR,and the best combinations for removing AR was temperature 30 ℃,pH=7.0,light intensity 6 000 lux,dissolved oxygen 5.0 mg/L and the fill rate 10%. According to the experimental data,equation model was proposed and coefficient of determination R2 =0.864 8,P<0.05. Samples T-test was done between the model predictions and the actual measured values.Test results showed that the significant difference of overall mean value sig. (2-tailed) was 0.978 (P>0.05),it Shows that had no significant difference between model predictions and the actual measured value,and model had a high degree of fitting.
基金Supported by grant from the Morning Star Fund of Shanghai, China, No. 99QB14010
文摘AIM： To study the effect of early intrajejunal nutrition on enzyme-protein synthesis and secretion during acute pancreatitis. METHODS： Fifteen dogs were randomly divided into parenteral nutrition （n = 7） and early intrajejunal nutrition groups （n = 8）. An acute pancreatitis model was induced by injecting 5% sodium taurocholate and trypsin into the pancreas via the pancreatic duct. Intrajejunal nutrition was delivered with a catheter via a jejunostomy tube after the model was established for 24 h. On d 1 and 7 and at the beginning of nutritional support, radioactive tracing and electron microscopes were used to evaluate the enzyme-protein synthesis in acinar cells, the subcellular fractionation and the change in zymogen granules after 1.85 × 10^6 Bq L-3H phenylalanine was infused at 30, 60, 120, and 180 min. RESULTS： The 3H radioactivity in pancreatic acinar cells reached its peak level at 60 min, and the contents in the early intrajejunal nutrition group were higher than those in the parenteral nutrition group, which were then decreased. The mean number and area of zymogen granules did not show any significant statistical difference in both groups on d i or on d 7 （P 〉 0.05）. CONCLUSION： Early intrajejunal nutrition might be effective in dogs with acute pancreatitis.
基金Under the auspices of National Natural Science Foundation of China (No. 40572170, 40871088 )
文摘On the basis of the soil environment investigation in Da＇an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter （SOM）, total N （TN）, total P （TP）, total K （TK）, available N （AN）, available P （AP） and available K （AK） were chosen as the evaluation factors. A regional soil nutrient evaluation model was developed based on the matter-element model. The results show that the soil samples with nutrient grade Ⅱ-Ⅴ respectively account for 10%, 30%, 32.5% and 27.5%, and those with grade Ⅳ and Ⅴ account for 60% in all samples. The relationship between soil nutrients and land types indicates that the nutrients of farmland are relatively good, with 41.7% of soil samples with the nutrient grade Ⅳ and Ⅴ. The nutrients of saline-alkali land and sandy land are the worst, with 100% of soil samples with the nutrient grade IV and V. And the ratios of soil samples grade IV and V in grassland and wasteland are respectively 62.5 % and 54.55%. Generally speaking, the soil nutrients status in Da＇an City is poor, 60% of soil samples are in poor and extremely poor conditions, indicating that the soil has been severely eroded. Being a relatively superior evaluation method with more accurate resuits and spatial distribution consistency, matter-element analysis is more suitable for regional soil nutrient evaluation than previous models.
基金Foundation item:Under the auspices of Shahrood University of Technology,Iran(No.348517)
文摘Soil macronutrients(i.e. nitrogen(N), phosphorus(P), and potassium(K)) are important soils components and knowing the spatial distribution of these parameters are necessary at precision agriculture. The purpose of this study was to evaluate the feasibility of different methods such as artificial neural networks(ANN) and two geostatistical methods(geographically weighted regression(GWR) and cokriging(CK)) to estimate N, P and K contents. For this purpose, soil samples were taken from topsoil(0–30 cm) at 106 points and analyzed for their chemical and physical parameters. These data were divided into calibration(n = 84) and validation(n = 22). Chemical and physical variables including clay, p H and organic carbon(OC) were used as auxiliary soil variables to estimate the N, P and K contents. Results showed that the ANN model(with coefficient of determination R^2 = 0.922 and root mean square error RMSE = 0.0079%) was more accurate compared to the CK model(with R^2 = 0.612 and RMSE = 0.0094%), and the GWR model(with R^2 = 0.872 and RMSE = 0.0089%) to estimate the N variable. The ANN model estimated the P with the RMSE of 3.630 ppm, which was respectively 28.93% and 20.00% less than the RMSE of 4.680 ppm and 4.357 ppm from the CK and GWR models. The estimated K by CK, GWR and ANN models have the RMSE of 76.794 ppm, 75.790 ppm and 52.484 ppm. Results indicated that the performance of the CK model for estimation of macro nutrients(N, P and K) was slightly lower than the GWR model. Also, the accuracy of the ANN model was higher than CK and GWR models, which proved to be more effective and reliable methods for estimating macro nutrients.
文摘Microglial activation plays an important role in a panel of neurological disorders such as multiple sclerosis(MS) and Parkinson's disease(PD),and is a key target for developing therapeutic strategies for these diseases.Ketogenic diet (KD),which is able to inhibit microglial activation in substantia nigra pars compacta of mice,has been shown effective in a mouse model of PD,possibly through increasing D-β-hydroxybutyrate(D-β-HB),a major component of ketone bodies.To verify this,we developed an in vitro model of microglia activation with a microglia line,BV-2,and investigated how D-β-HB have an effect on the LPS-stimulated BV-2 cells.We found D-β-HB is able to recover the cell viability,and inhibit the production of inflammatory mediators and cytokines such as ROS,nitrite,IL-1β,TNF-α,and IL-6,which otherwise were increased in LPS-stimulated BV-2 cells.We conclude that the LPS induced BV-2 cells activation is a valid in vitro model of microglia activation.D-β-HB is able to suppress the activation of BV-2 cells, which might account for one of the possible reasons of KD therapy on the PD model.
