Executive functions emerge throughout childhood and shape multiple cognitive and behavioral outcomes across the lifespan.Given the importance of these functions,there is considerable interest in understanding the role...Executive functions emerge throughout childhood and shape multiple cognitive and behavioral outcomes across the lifespan.Given the importance of these functions,there is considerable interest in understanding the role of environmental enrichment to support their development.The past 20 years have seen the emergence of a body of evidence around the beneficial effects of engaging in physical activity for executive functioning in children.Despite this,there are still unanswered questions,particularly about the confounding effects of the timing and dose of exercise-based interventions.During development,sensitive periods with heightened neural plasticity and sensitivity to environmental influences can offer an optimal time to introduce enrichment interventions.As such,sensitive periods for executive function could indicate an ideal time to introduce physical activity or be a potential confounder to study results if not considered.This narrative review discusses the potential presence of sensitive periods in preadolescent development where physical activity has greater benefits for executive function.Initially,we briefly review the largely parallel fields investigating the presence of sensitive periods for executive function and the effects of physical activity on executive function outcomes.We then bring together these 2 concepts to discuss the theoretical basis for developmentally sensitive periods during which children may be particularly amenable to physical activity-based interventions and offer potential ways forward to investigate this phenomenon.We hope this review will attract researchers to collaborate in the area and extend our current understanding of the development of executive functions as well as interventions like physical activity.展开更多
The kidney is essential for maintaining fluid,electrolyte,and metabolite homeostasis,and for regulating blood pressure.The pig serves as a valuable biomedical model for human renal physiology,offering insights across ...The kidney is essential for maintaining fluid,electrolyte,and metabolite homeostasis,and for regulating blood pressure.The pig serves as a valuable biomedical model for human renal physiology,offering insights across different physiological states.In this study,single-cell RNA sequencing was used to profile 138469 cells from 12 pig kidney samples collected during the embryonic(E),fattening(F),and pregnancy(P)periods,identifying 29 cell types.Proximal tubule(PT)cells exhibited elevated expression of metabolism-related transcription factors(TFs),including GPD1,ACAA1,and AGMAT,with validation across multiple individuals,periods,and species.Fluorescence homologous double-labeling of paraffin sections further confirmed the expression of ACAA1 and AGMAT in PT cells.Comparative analysis of pig and human kidneys revealed a high degree of similarity among corresponding cell types.Analysis of cell-type heterogeneity highlighted the diversity of thick ascending limb(TAL)cells,identifying a TAL subpopulation related to immune function.Additionally,the functional heterogeneity of kidney-resident macrophages(KRM)was explored across different anatomical sites.In the renal medulla,KRM were implicated in phagocytosis and leukocyte activation,whereas in the renal pelvis,they functioned as ligands,recruiting neutrophils with bactericidal activity to the renal pelvis to combat urinary tract infections.展开更多
Repeated wet swelling and dry shrinkage of soil leads to the gradual occurrence of cracks and the formation of a complex fracture network.In order to study the development characteristics and quantitative analysis of ...Repeated wet swelling and dry shrinkage of soil leads to the gradual occurrence of cracks and the formation of a complex fracture network.In order to study the development characteristics and quantitative analysis of cracks in root-soil complex in different growth periods under dry-wet cycles,the alfalfa root-loess complex was in-vestigated during different growth periods under different dry-wet cycles,and a dry-wet cycle experiment was conducted.The crack rate,relative area,average width,total length,and the cracks fractal dimension in the root-soil complex were extracted;the crack development characteristics of plain soil were analyzed under the PG-DwC(dry-wet cycle caused by plant water management during plant growth period),as well as the crack development characteristics of root-soil complex under PG-DWC and EC-DWC(the dry-wet cycles caused by extreme natural conditions such as continuous rain);the effects of plant roots and dry-wet cycles on soil cracks were discussed.The results showed that the average crack width,crack rate,relative crack area,and total crack length of the alfalfa root-loess complex were higher than those of the plain soil during PG-DWC.The result indicated that compared with plain soil during PG-DWC,the presence of plant roots in alfalfa root-soil complex in the same growth period promoted the cracks development to some extent.The alfalfa root-soil complex crack parameters during different growth periods were relatively stable during PG-DWC(O dry-wet cycle).During EC-DWC(1,3,and 5 dry-wet cycles),the alfalfa root-loess complex crack parameters increased with the number of dry-wet cycles during different growth periods.Unlike PG-DWC,the EC-DWC accelerated crack development,and the degree of crack development increased with the number of dry-wet cycles.The existence of plant roots promoted crack development and expansion in the root-soil complex to a certain extent,and the dry-wet cycle certainly promoted crack development and expansion in the root-soil complex.This result contradicts the im-provement in the root-soil complex's macro-mechanical properties during plant growth,due to differences in the mechanical properties of roots and soil.The research results will provide reference for the root soil complex crack development law and the design of slope protection by vegetation.展开更多
Background: Infertility is characterized by the inability to conceive after a year of regular unprotected intercourse. Aims: This study aimed to investigate the diagnostic value of sex hormone levels during different ...Background: Infertility is characterized by the inability to conceive after a year of regular unprotected intercourse. Aims: This study aimed to investigate the diagnostic value of sex hormone levels during different physiological periods in the diagnosis of infertility patients. Methods: From December 2019 to May 2021, a total of 93 infertility patients were admitted and selected as the observation group. Among them, 31 cases were in the follicular stage, 31 cases in the ovulation stage, and 31 cases in the luteal stage. Ninety-three healthy women for fertility evaluation due to male infertility were selected as the control group. The control group included 31 women in the follicular phase, 31 women in the ovulatory phase, and 31 women in the luteal phase. The levels of sex hormones (prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), testosterone (T), and progesterone (P)) during different physiological phases were compared between the observation and control groups. Results: The follicular phase showed no significant difference in LH levels between the observation group and the control group. The observation group showed higher levels of PRL and P compared to the control group, while the levels of FSH, E2, and T were lower in the observation group compared to the control group. The ovulation phase showed no significant difference in PRL levels between the two groups. The observation group showed lower levels of LH, FSH, E2, T, and P compared to the control group. The luteal phase showed no statistical difference in E2 levels between the two groups. The observation group showed higher levels of PRL, LH, and FSH compared to the control group, while the levels of T and P were lower in the observation group compared to the control group. Conclusion: Infertile women show variations in hormone levels compared to the normal levels during the follicular phase, ovulatory phase, and luteal phase.展开更多
Artificial vegetation restoration is the main measure for vegetation restoration and soil and water conservation in alpine mine dumps on the Qinghai-Tibet Plateau,China.However,there are few reports on the dynamic cha...Artificial vegetation restoration is the main measure for vegetation restoration and soil and water conservation in alpine mine dumps on the Qinghai-Tibet Plateau,China.However,there are few reports on the dynamic changes and the influencing factors of the soil reinforcement effect of plant species after artificial vegetation restoration under different recovery periods.We selected dump areas of the Delni Copper Mine in Qinghai Province,China to study the relationship between the shear strength and the peak displacement of the root-soil composite on the slope during the recovery period,and the influence of the root traits and soil physical properties on the shear resistance characteristics of the root-soil composite via in situ direct shear tests.The results indicate that the shear strength and peak displacement of the rooted soil initially decreased and then increased with the increase of the recovery period.The shear strength of the rooted soil and the recovery period exhibited a quadratic function relationship.There is no significant function relationship between the peak displacement and the recovery period.Significant positive correlations(P<0.05)exists between the shear strength of the root-soil composite and the root biomass density,root volume density,and root area ratio,and they show significant linear correlations(P<0.05).There are no significant correlations(P>0.05)between the shear strength of the root-soil composite and the root length density,and the root volume ratio of the coarse roots to the fine roots.A significant negative linear correlation(P<0.05)exists between the peak displacement of the rooted soil and the coarse-grain content,but no significant correlations(P>0.05)with the root traits,other soil physical property indices(the moisture content and dry density of the soil),and slope gradient.The coarse-grain content is the main factor controlling the peak displacement of the rooted soil.展开更多
The Oriental Reed Warbler(Acrocephalus orientalis)is one of the most commonly used hosts for the parasitic Common Cuckoo(Cuculus canorus).However,as hosts that feed unrelated parasitic nestlings may suffer extra repro...The Oriental Reed Warbler(Acrocephalus orientalis)is one of the most commonly used hosts for the parasitic Common Cuckoo(Cuculus canorus).However,as hosts that feed unrelated parasitic nestlings may suffer extra reproductive costs,they may be less willing to care for nestlings that have prolonged nestling periods.To test this hypothesis,the duration of feeding by Oriental Reed Warblers under natural conditions for their own nestlings was compared with the duration of feeding under natural conditions for Common Cuckoo nestlings and for artificially prolonged cuckoo nestlings.The results showed that Oriental Reed Warblers did not starve,drive away,or desert any of the nestlings in the experiment,and neither parent was left alone.Our experimental study indicates that both Oriental Reed Warbler parents were willing to care for nestlings with a prolonged nestling period(up to 30 days,twice the average duration time that the Oriental Reed Warblers fed their own chicks in natural conditions).However,further experiments and observations are required in other host bird species to examine whether both parents or one of the parents may exhibit the behavior of abandoning nestlings with a prolonged nestling period.展开更多
The effect of MnO4- and silver content on electrochemical behaviour of five commercial Pb-Ag alloy anodes was studied in acid zinc sulphate electrolyte with and without MnO4- ions at 38 °C during potential decay ...The effect of MnO4- and silver content on electrochemical behaviour of five commercial Pb-Ag alloy anodes was studied in acid zinc sulphate electrolyte with and without MnO4- ions at 38 °C during potential decay periods. When the anodes were immersed into acid zinc sulphate electrolyte without MnO4- ions, the Pb-0.72%Ag anode entered complete passivation state in the shortest time among the five anodes, followed by anodes Pb-0.67%Ag, Pb-0.60%Ag, Pb-0.58%Ag and Pb-0.29%Ag-0.1%Ca by measurement of open circuit potential. During immersion of the anodes, MnO4 ions accelerated the passivation and increased the corrosion current density of the anodes. After immersion in zinc electrolyte with MnO4-, the anode Pb-0.72%Ag had the best corrosion resistance, followed by anodes Pb-0.67%Ag, Pb-0.60%Ag, then the close anodes Pb-0.58%Ag and Pb-0.29%Ag-0.1%Ca by the electrochemical impedance spectroscopy （EIS） analysis.展开更多
The accurate evaluation of maize stalk lodging resistance in different growth periods enables timely management of lodging risks and ensures stable and high maize yields.Here,we established five diferent sowing dates ...The accurate evaluation of maize stalk lodging resistance in different growth periods enables timely management of lodging risks and ensures stable and high maize yields.Here,we established five diferent sowing dates to create diferent conditions for maize growth.We evaluated the effects of the different growth conditions on lodging resistance by determining stalk morphology,moisture content,mechanical strength and dry matter,and the relationship between stalk breaking force and these indicators during the silking stage(R1),milk stage(R3),physiological maturity stage(R6),and 20 days after R6.Plant height at R1 positively affected stalk breaking force.At R3,the cofficient of ear height and the dry weight per unit length of basal internodes were key indicators of stalk lodging resistance.At R6,the key indicators were the coefficient of the center of gravity height and plant fresh weight.After R6,the key indicator was the coefficient of the center of gravity height.The crushing strength of the fourth internode correlated significanty and positively with the stalk breaking force from R1 to R6,which indicates that crushing strength is a reliable indicator of stalk mechanical strength.These results suggest that high stalk strength and low ear height beneft lodging resistance prior to R6.During and after R6,the cofficient of the center of gravity height and the mechanical strength of basal internodes can be used to evaluate plant lodging resistance and the appropriate time for harvesting in fields with a high lodging risk.展开更多
Future changes in the 50-yr return level for temperature and precipitation extremes over China's Mainland are investigated based on a CMIP5 multi-model ensemble for RCP2.6, RCP4.5 and RCP8.5 scenarios. The followi...Future changes in the 50-yr return level for temperature and precipitation extremes over China's Mainland are investigated based on a CMIP5 multi-model ensemble for RCP2.6, RCP4.5 and RCP8.5 scenarios. The following indices are analyzed： TXx and TNn （the annual maximum and minimum of daily annual maximum consecutive 5-day precipitation） and CDD maximum and minimum surface temperature）, RX5day （the （maximum annual number of consecutive dry days）. After first validating the model performance, future changes in the 50-yr return values and return periods for these indices are investigated along with the inter-model spread. Multi-model median changes show an increase in the 50-yr return values of TXx and a decrease for TNn, more specifically, by the end of the 21st century under RCP8.5, the present day 50-yr return period of warm events is reduced to 1.2 yr, while extreme cold events over the country are projected to essentially disappear. A general increase in RX5day 50-yr return values is found in the future. By the end of the 21st century under RCP8.5, events of the present RX5day 50-yr return period are projected to reduce to 〈 10 yr over most of China. Changes in CDD-50 show a dipole pattern over China, with a decrease in the values and longer return periods in the north, and vice versa in the south. Our study also highlights the need for further improvements in the representation of extreme events in climate models to assess the future risks and engineering design related to large-scale infrastructure in China.展开更多
Aiming at the uniform features of acceleration response spectra, two scalar periods-the response spectral predominant period Tp and the smoothed spectral predominant period To are employed to normalize the abscissa of...Aiming at the uniform features of acceleration response spectra, two scalar periods-the response spectral predominant period Tp and the smoothed spectral predominant period To are employed to normalize the abscissa of the normalized response spectra （NRS） of ground motions, respectively. Engineering characteristics of 5% -damped NRS, and the bi-normalized response spectra （BNRS） are investigated accounting for the effects of soil condition and fault distance. Nearly 600 horizontal ground motion components during the Chi-Chi earthquake are included in the analysis. It shows that the NRS strongly depends on soil condition and fault distance. However, soil condition and distance have only a slight influence on two kinds of BNRS. Dispersion analysis indicates that such normalization can reduce scatter in the derivation of response spectral shapes. Finally, a parametric analysis of the scalar periods （Tp, To） is performed and then compared with those of previous studies. These special and particular aspects of earthquake response spectra and scalar periods need to be considered in developing earthquake-resistant design criteria.展开更多
This study applies ArcGIS to analyze the spatiotemporal distribution of cultural sites in the Ill River Valley in northwestern China. It explores relationships between the sites＇ spatiotemporal evolutionary character...This study applies ArcGIS to analyze the spatiotemporal distribution of cultural sites in the Ill River Valley in northwestern China. It explores relationships between the sites＇ spatiotemporal evolutionary characteristics, human history, and the natural environment. The results indicate that the numbers and proportions of the sites, and the frequency of their oc- currence, exhibited an inverted V-shaped change trend during six historical periods. The ＂high in the east and low in the west＂ spatial distribution pattern of the first three periods shifted to the one the ＂high in the west and low in the east＂ during the latter three periods, demonstrating a change in the spatial center of gravity of human activities. The sites were mainly distributed on slopes of grades 1-5, with their proportions increasing from 75% during the Spring and Autumn Period （770 BC-476 BC）-Qin Dynasty （221 BC-207 BC） to 93.75% during the Qing Dynasty-Modern period. The concentrated distribution of site elevations shifted from grades 4-8 during the Spring and Autumn Period-Qin Dynasty, and the Western Han （206 BC-8）-Southern and Northern Dynasties （420-589）, to grades 1-4 during the latter three periods. The number of sites showed a shifting trend from high-elevation mountains and hills to low-elevation plains, and from high slopes to low slopes. In particular, the sites exhibited a special ＂moist＂ evolutionary pattern of migration from middle and upstream areas to downstream areas, as opposed to the migration pattern of sites located in typical arid areas. The study also considered factors influencing the distribution and spatiotemporal evolution of cultural sites, notably, human factors and natural factors.展开更多
The weights of the drought risk index （DRI）, which linearly combines the reliability, resiliency, and vulnerability, are difficult to obtain due to complexities in water security during drought periods. Therefore, d...The weights of the drought risk index （DRI）, which linearly combines the reliability, resiliency, and vulnerability, are difficult to obtain due to complexities in water security during drought periods. Therefore, drought entropy was used to determine the weights of the three critical indices. Conventional simulation results regarding the risk load of water security during drought periods were often regarded as precise. However, neither the simulation process nor the DRI gives any consideration to uncertainties in drought events. Therefore, the Dempster-Shafer （D-S） evidence theory and the evidential reasoning algorithm were introduced, and the DRI values were calculated with consideration of uncertainties of the three indices. The drought entropy and evidential reasoning algorithm were used in a case study of the Haihe River Basin to assess water security risks during drought periods. The results of the new DRI values in two scenarios were compared and analyzed. It is shown that the values of the DRI in the D-S evidence algorithm increase slightly from the original results of Zhang et al. （2005）, and the results of risk assessment of water security during drought periods are reasonable according to the situation in the study area. This study can serve as a reference for further practical application and planning in the Haihe River Basin, and other relevant or similar studies.展开更多
In this paper, we present an interval model of networked control systems with time-varying sampling periods and time-varying network-induced delays and discuss the problem of stability of networked control systems usi...In this paper, we present an interval model of networked control systems with time-varying sampling periods and time-varying network-induced delays and discuss the problem of stability of networked control systems using Lyapunov stability theory. A sufficient stability condition is obtained by solving a set of linear matrix inequalities. In the end, the illustrative example demonstrates the correctness and effectiveness of the proposed approach.展开更多
Estivation, hibernation, and starvation are indispensable inactive states of sea cucumbers Apostichopusjaponicus in nature and in culture ponds. Generally, temperature is the principal factor that induces estivation o...Estivation, hibernation, and starvation are indispensable inactive states of sea cucumbers Apostichopusjaponicus in nature and in culture ponds. Generally, temperature is the principal factor that induces estivation or hibernation in the sea cucumber. The present study provided insight into the physiological adaptations ofA. japonicus during the three types of inactivity （hibernation, estivation, and starvation） by measuring the oxygen consumption rates （Vo2） and biochemical compositions under laboratory conditions of low （3℃）, normal （17℃） and high （24℃） temperature. The results show that the characteristics of A. japonicus in dormancy （hibernation and estivation） states were quite different from higher animals, such as fishes, amphibians, reptiles, and mammals, but more closely resembled a semi-dormant state. It was observed that the shift in the A. japonicus physiological state from normal to dormancy was a chronic rather than acute process, indicated by the gradual depression of metabolic rate. While metabolic rates declined 44.9% for the estivation group and 71.7% for the hibernation group, relative to initial rates, during the 36 d culture period, metabolic rates were not maintained at constant levels during these states. The metabolic depression processes for sea cucumbers in hibernation and estivation appeared to be a passive and an active metabolic suppression, respectively. In contrast, the metabolic rates （128.904-11.70 μg/g h） of estivating sea cucumbers were notably higher （107.85±6.31 μg/gh） than in starving sea cucumbers at 17℃, which indicated that the dormancy mechanism here, as a physiological inhibition, was not as efficient as in higher animals. Finally, the principle metabolic substrate or energy source of sea cucumbers in hibernation was lipid, whereas in estivation they mainly consumed protein in the early times and both protein and lipid thereafter.展开更多
The growth periods（GPs, from planting/emergence to reproductive stage 8（R8） of soybean cultivars vary in different ecological regions, especially in China with a very complex soybean cropping system. In this study,...The growth periods（GPs, from planting/emergence to reproductive stage 8（R8） of soybean cultivars vary in different ecological regions, especially in China with a very complex soybean cropping system. In this study, a 3-yr experimental study was undertaken in three geographical locations of China from 2008 to 2010, including the Northeast（40.66-45.85°N）, Huang-Huai（34.75-38.04°N） and southern（22.82-30.60°N） eco-regions with about 250 accessions in each region to clarify the classification of maturity group（MG） and identify the cultivars with stable GP to increase the knowledge about the GP distribution of soybean cultivars in China. GPs of soybean cultivars in different eco-regions were significant different with a gradual decrease from 115-125 d in the Northeast part to the 85-100 d in the southern part of China. The geographical location was the major factor for GP of cultivars from the Northeast, while the year of planting was the major factor affecting the stability of GPs in Huang-Huai summer and southern summer soybean. AMMI2（additive main effects and multiplicativeinteraction）-Biplot analysis showed that the GPs of soybean cultivars from the Northeast eco-region have a comparatively satisfactory environmental stability. Moreover, soybean cultivars with moderate GP/MG and stable environment adaptability in different eco-regions were identified based on the linear regression and AMMI analysis, which was important for the accurate classification of soybean MGs in future. Taken together, our results reflected the genetic diversity, geographical distribution and environmental stability of the Chinese soybean GP trait. Soybean cultivars with stable GP for various Chinese eco-regions would be beneficial for Chinese soybean genetic improvement, varietal introduction, exchange, and soybean breeding program for wide adaptability.展开更多
SO_4^(2-) and NO_3^- are important chemical components of fine particulate matter(PM_(2.5)),especially during haze periods.This study selected two haze episodes in Beijing,China with similar meteorological conditions....SO_4^(2-) and NO_3^- are important chemical components of fine particulate matter(PM_(2.5)),especially during haze periods.This study selected two haze episodes in Beijing,China with similar meteorological conditions.A monitoring-modeling approach was developed to estimate the secondary conversion ratios of sulfur and nitrogen based on monitored and simulated concentrations.Measurements showed that in Episode 1(24th–25th October,2014),the concentrations(proportions)of SO_4^(2-) and NO_3^- reached 35.1μg/m^3(14.9%) and 55.0μg/m^3(22.9%),while they reached 14.4μg/m^3(9.3%) and 59.1μg/m^3(38.1%)in Episode 2(26th–27th October,2017).A modeling system was applied to apportion Beijing's SO_4^(2-) and NO_3^- in primary and secondary SO_4^(2-)/NO_3^- emitted from local and regional sources.Thus,secondary conversion contributions considering the local and regional level were defined.The former primarily focused on Beijing atmospheric oxidation ability and the latter mainly considered the existence form of Beijing SO_4^(2-)/NO_3^- under the regional transport impacts.Finally,secondary oxidation ratios were estimated through combining secondary conversion contribution coefficients for simulated and monitored concentrations.At regional level,sulfur oxidation ratios in polluted(clean)days during two sampling periods were0.57–0.72(0.07–0.52)and 0.74–0.80(0.08–0.61),nitrogen oxidation ratios were 0.20–0.29(0.05–0.15)and 0.34–0.38(0.02–0.29),indicating that atmospheric oxidation was enhanced when considering regional transport through 2014–2017.At the local level,sulfur oxidation ratios were 0.66–0.71(0.04–0.48)in haze(clean)days,while nitrogen oxidation ratios were0.16–0.29(0.02–0.16).The atmospheric oxidation ability markedly increased in PM_(2.5)pollution days,but changed only slightly between the two periods.展开更多
[Objective] The paper was to study the nitrogen application amount and nitrogen application model for high grade hybrid rapeseed （Brassica napus L.） to get high yield. [Method] With ＂Youyan 599＂ and ＂Sanbei 98＂ ...[Objective] The paper was to study the nitrogen application amount and nitrogen application model for high grade hybrid rapeseed （Brassica napus L.） to get high yield. [Method] With ＂Youyan 599＂ and ＂Sanbei 98＂ as materials, using quadratic regression orthogonal gyration combination design, the impact of nitrogen application amount during various periods on rapeseed yield was studied. [Result] The combinations of factors to obtain the highest yield index （2 898.211 kg / hm 2 ） of ＂Youyan 599＂ were as follows： living rape fertilizer 89.27 kg / hm 2 , opening fertilizer 120 kg / hm 2 , 12 th lunar month fertilizer 101.12 kg / hm 2 , total nitrogen application amount 310.39 kg / hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12th lunar month fertilizer were 28.76%, 38.66% and 32.58%, respectively. The combinations of factors to obtain the highest yield index （2 870.14 kg/hm 2 ） of ＂Sanbei 98＂ were as follows： living rape fertilizer 120 kg / hm 2 , opening fertilizer 120 kg / hm 2 , 12 th lunar month fertilizer 37.55kg / hm 2 , total nitrogen application amount 277.55 kg / hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12 th lunar month fertilizer were 43.24%, 43.24% and 13.53%, respectively. The combinations of factors to obtain the highest yield index of two combined varieties （2 813.82 kg/hm 2 ）were as follows： living rape fertilizer 120 kg/hm 2 , opening fertilizer 120 kg/hm 2 , 12 th lunar month fertilizer 76.23 kg/hm 2 , total nitrogen application amount 316.23 kg/hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12 th lunar month fertilizer were 37.95% , 37.95% and 24.11% , respectively. [Conclusion] The paper provided theoretical basis for high yield cultivation of high grade hybridized rapeseed.展开更多
A batch experiment was performed to investigate nonequilibrium adsorption behavior of atrazine （2-chloro-4-ethylamino-6-isopropylamlno-1,3,5-triazlne） on a fluvo-aquic soil. The amount of atrazine sorbed increased w...A batch experiment was performed to investigate nonequilibrium adsorption behavior of atrazine （2-chloro-4-ethylamino-6-isopropylamlno-1,3,5-triazlne） on a fluvo-aquic soil. The amount of atrazine sorbed increased with increasing adsorption contact periods. For a range of initial atrazlne concentrations, the percentage of atrazine sorbed within 24 h ranged from 24% to 77% of the observed total amount sorbed for the longest contact period; when adsorption contact periods were more than 72 h, the deviations in curves fitted using a nonlinear Freundllch equation gradually became less. The opposite trend was observed for the atrazine concentrations in solution. The effect of adsorption contact periods on atrazine adsorption behavior was evaluated by interpreting the temporal variations in linear and nonlinear Freundlich equation parameters obtained from the phase-distribution relationships. As the adsorption contact period increased, the nonlinear Freundlich capacity coefficient kf showed a significant linear increase （r^2 = 0.9063, P 〈 0.001）. However, a significant negative linear correlation was observed for the nonlinear coefficient n, a dimensionless parameter （r^2 = 0.5666, P 〈 0.05）. Furthermore, the linear distribution coefficient kd ranged from 0.38 to 1.44 and exhibited a significant linear correlation to the adsorption contact period （r^2 = 0.72, P 〈 0.01）. The parameters kf and n obtained from a time-dependent isotherm rather than the distribution coefficient kd estimated using the linear Freundlich equation were more appropriate to predict the herbicide residue in the field and thus more meaningful for environmental assessment.展开更多
This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation ...This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation in China has exhibited significant 50–70-yr, 100–120-yr, and 200–250-yr cycles. Results also show that the amplitudes of decadal and centennial temperature variation were 1.3℃ and 0.7℃, respectively, with the latter significantly correlated with long-term changes in solar radiation, especially cold periods, which correspond approximately to sunspot minima. The most rapid warming in China occurred over AD 1870–2000, at a rate of 0.56°± 0.42℃（100 yr）^（-1）; however, temperatures recorded in the 20 th century may not be unprecedented for the last 2000 years, as data show records for the periods AD 981–1100 and AD1201–70 are comparable to the present. The ensemble means of dryness/wetness spatial patterns in eastern China across all centennial warm periods illustrate a tripole pattern： dry south of 25°N, wet from 25°–30°N, and dry to the north of 30°N. However, for all centennial cold periods, this spatial pattern also exhibits a meridional distribution. The increase in precipitation over the monsoonal regions of China associated with the 20 th century warming can primarily be attributed to a mega El Nino–Southern Oscillation and the Atlantic Multidecadal Oscillation. In addition, a significant association between increasing numbers of locusts and dry/cold conditions is found in eastern China. Plague intensity also generally increases in concert with wetness in northern China, while more precipitation is likely to have a negative effect in southern China.展开更多
In this study,Cordyceps militaris strain QC04 was cultivated in oat,rice,and wheat media for different time periods.We studied the effects of different cultivation media and periods on the fruiting body biomass and ac...In this study,Cordyceps militaris strain QC04 was cultivated in oat,rice,and wheat media for different time periods.We studied the effects of different cultivation media and periods on the fruiting body biomass and active components of C.militaris,aiming to provide reference for the production and utilization of C.militaris QC04.The results showed that the dry weight of the fruiting body of C.militaris was the highest in the wheat medium,moderate in the oat medium,and the lowest in the rice medium.The content of cordycepin and adenosine in the fruiting body and residual medium was higher in the oat and rice media than in the rice medium.The content of cordycepin and adenosine in fruiting body and residual medium peaked on day 55.Furthermore,the content of cordycepin in the fruiting body was lower than that in the residual medium,while the content of adenosine showed an opposite trend.The content of cordycepic acid in the rice medium was generally higher than that in the oat and wheat media.As the cultivation period extended,the fruiting body biomass declined and the content of cordycepic acid in the fruiting body increased slightly.展开更多
文摘Executive functions emerge throughout childhood and shape multiple cognitive and behavioral outcomes across the lifespan.Given the importance of these functions,there is considerable interest in understanding the role of environmental enrichment to support their development.The past 20 years have seen the emergence of a body of evidence around the beneficial effects of engaging in physical activity for executive functioning in children.Despite this,there are still unanswered questions,particularly about the confounding effects of the timing and dose of exercise-based interventions.During development,sensitive periods with heightened neural plasticity and sensitivity to environmental influences can offer an optimal time to introduce enrichment interventions.As such,sensitive periods for executive function could indicate an ideal time to introduce physical activity or be a potential confounder to study results if not considered.This narrative review discusses the potential presence of sensitive periods in preadolescent development where physical activity has greater benefits for executive function.Initially,we briefly review the largely parallel fields investigating the presence of sensitive periods for executive function and the effects of physical activity on executive function outcomes.We then bring together these 2 concepts to discuss the theoretical basis for developmentally sensitive periods during which children may be particularly amenable to physical activity-based interventions and offer potential ways forward to investigate this phenomenon.We hope this review will attract researchers to collaborate in the area and extend our current understanding of the development of executive functions as well as interventions like physical activity.
基金supported by the International Cooperation and Exchange Program of the National Natural Science Foundation of China(32261133531)。
文摘The kidney is essential for maintaining fluid,electrolyte,and metabolite homeostasis,and for regulating blood pressure.The pig serves as a valuable biomedical model for human renal physiology,offering insights across different physiological states.In this study,single-cell RNA sequencing was used to profile 138469 cells from 12 pig kidney samples collected during the embryonic(E),fattening(F),and pregnancy(P)periods,identifying 29 cell types.Proximal tubule(PT)cells exhibited elevated expression of metabolism-related transcription factors(TFs),including GPD1,ACAA1,and AGMAT,with validation across multiple individuals,periods,and species.Fluorescence homologous double-labeling of paraffin sections further confirmed the expression of ACAA1 and AGMAT in PT cells.Comparative analysis of pig and human kidneys revealed a high degree of similarity among corresponding cell types.Analysis of cell-type heterogeneity highlighted the diversity of thick ascending limb(TAL)cells,identifying a TAL subpopulation related to immune function.Additionally,the functional heterogeneity of kidney-resident macrophages(KRM)was explored across different anatomical sites.In the renal medulla,KRM were implicated in phagocytosis and leukocyte activation,whereas in the renal pelvis,they functioned as ligands,recruiting neutrophils with bactericidal activity to the renal pelvis to combat urinary tract infections.
基金the Key Research and Development Project of Ningxia Hui Autonomous Region(No.2023BEG02072)for their financial support.
文摘Repeated wet swelling and dry shrinkage of soil leads to the gradual occurrence of cracks and the formation of a complex fracture network.In order to study the development characteristics and quantitative analysis of cracks in root-soil complex in different growth periods under dry-wet cycles,the alfalfa root-loess complex was in-vestigated during different growth periods under different dry-wet cycles,and a dry-wet cycle experiment was conducted.The crack rate,relative area,average width,total length,and the cracks fractal dimension in the root-soil complex were extracted;the crack development characteristics of plain soil were analyzed under the PG-DwC(dry-wet cycle caused by plant water management during plant growth period),as well as the crack development characteristics of root-soil complex under PG-DWC and EC-DWC(the dry-wet cycles caused by extreme natural conditions such as continuous rain);the effects of plant roots and dry-wet cycles on soil cracks were discussed.The results showed that the average crack width,crack rate,relative crack area,and total crack length of the alfalfa root-loess complex were higher than those of the plain soil during PG-DWC.The result indicated that compared with plain soil during PG-DWC,the presence of plant roots in alfalfa root-soil complex in the same growth period promoted the cracks development to some extent.The alfalfa root-soil complex crack parameters during different growth periods were relatively stable during PG-DWC(O dry-wet cycle).During EC-DWC(1,3,and 5 dry-wet cycles),the alfalfa root-loess complex crack parameters increased with the number of dry-wet cycles during different growth periods.Unlike PG-DWC,the EC-DWC accelerated crack development,and the degree of crack development increased with the number of dry-wet cycles.The existence of plant roots promoted crack development and expansion in the root-soil complex to a certain extent,and the dry-wet cycle certainly promoted crack development and expansion in the root-soil complex.This result contradicts the im-provement in the root-soil complex's macro-mechanical properties during plant growth,due to differences in the mechanical properties of roots and soil.The research results will provide reference for the root soil complex crack development law and the design of slope protection by vegetation.
文摘Background: Infertility is characterized by the inability to conceive after a year of regular unprotected intercourse. Aims: This study aimed to investigate the diagnostic value of sex hormone levels during different physiological periods in the diagnosis of infertility patients. Methods: From December 2019 to May 2021, a total of 93 infertility patients were admitted and selected as the observation group. Among them, 31 cases were in the follicular stage, 31 cases in the ovulation stage, and 31 cases in the luteal stage. Ninety-three healthy women for fertility evaluation due to male infertility were selected as the control group. The control group included 31 women in the follicular phase, 31 women in the ovulatory phase, and 31 women in the luteal phase. The levels of sex hormones (prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), testosterone (T), and progesterone (P)) during different physiological phases were compared between the observation and control groups. Results: The follicular phase showed no significant difference in LH levels between the observation group and the control group. The observation group showed higher levels of PRL and P compared to the control group, while the levels of FSH, E2, and T were lower in the observation group compared to the control group. The ovulation phase showed no significant difference in PRL levels between the two groups. The observation group showed lower levels of LH, FSH, E2, T, and P compared to the control group. The luteal phase showed no statistical difference in E2 levels between the two groups. The observation group showed higher levels of PRL, LH, and FSH compared to the control group, while the levels of T and P were lower in the observation group compared to the control group. Conclusion: Infertile women show variations in hormone levels compared to the normal levels during the follicular phase, ovulatory phase, and luteal phase.
基金supported by the Project of Qinghai Science&Technology Department(Grant No.2021-ZJ-956Q).
文摘Artificial vegetation restoration is the main measure for vegetation restoration and soil and water conservation in alpine mine dumps on the Qinghai-Tibet Plateau,China.However,there are few reports on the dynamic changes and the influencing factors of the soil reinforcement effect of plant species after artificial vegetation restoration under different recovery periods.We selected dump areas of the Delni Copper Mine in Qinghai Province,China to study the relationship between the shear strength and the peak displacement of the root-soil composite on the slope during the recovery period,and the influence of the root traits and soil physical properties on the shear resistance characteristics of the root-soil composite via in situ direct shear tests.The results indicate that the shear strength and peak displacement of the rooted soil initially decreased and then increased with the increase of the recovery period.The shear strength of the rooted soil and the recovery period exhibited a quadratic function relationship.There is no significant function relationship between the peak displacement and the recovery period.Significant positive correlations(P<0.05)exists between the shear strength of the root-soil composite and the root biomass density,root volume density,and root area ratio,and they show significant linear correlations(P<0.05).There are no significant correlations(P>0.05)between the shear strength of the root-soil composite and the root length density,and the root volume ratio of the coarse roots to the fine roots.A significant negative linear correlation(P<0.05)exists between the peak displacement of the rooted soil and the coarse-grain content,but no significant correlations(P>0.05)with the root traits,other soil physical property indices(the moisture content and dry density of the soil),and slope gradient.The coarse-grain content is the main factor controlling the peak displacement of the rooted soil.
基金supported by the National Natural Science Foundation of China(Nos.32270526 to WL,32260253 to LW and 32101242 to LM)。
文摘The Oriental Reed Warbler(Acrocephalus orientalis)is one of the most commonly used hosts for the parasitic Common Cuckoo(Cuculus canorus).However,as hosts that feed unrelated parasitic nestlings may suffer extra reproductive costs,they may be less willing to care for nestlings that have prolonged nestling periods.To test this hypothesis,the duration of feeding by Oriental Reed Warblers under natural conditions for their own nestlings was compared with the duration of feeding under natural conditions for Common Cuckoo nestlings and for artificially prolonged cuckoo nestlings.The results showed that Oriental Reed Warblers did not starve,drive away,or desert any of the nestlings in the experiment,and neither parent was left alone.Our experimental study indicates that both Oriental Reed Warbler parents were willing to care for nestlings with a prolonged nestling period(up to 30 days,twice the average duration time that the Oriental Reed Warblers fed their own chicks in natural conditions).However,further experiments and observations are required in other host bird species to examine whether both parents or one of the parents may exhibit the behavior of abandoning nestlings with a prolonged nestling period.
基金Project(RDCPJ346365-06)supported by the Natural Sciences and Engineering Research Council of CanadaProject(51208193)supported by the National Natural Science Foundation of ChinaProject(11jj6034)supported by the Hunan Provincial Natural Science Foundation
文摘The effect of MnO4- and silver content on electrochemical behaviour of five commercial Pb-Ag alloy anodes was studied in acid zinc sulphate electrolyte with and without MnO4- ions at 38 °C during potential decay periods. When the anodes were immersed into acid zinc sulphate electrolyte without MnO4- ions, the Pb-0.72%Ag anode entered complete passivation state in the shortest time among the five anodes, followed by anodes Pb-0.67%Ag, Pb-0.60%Ag, Pb-0.58%Ag and Pb-0.29%Ag-0.1%Ca by measurement of open circuit potential. During immersion of the anodes, MnO4 ions accelerated the passivation and increased the corrosion current density of the anodes. After immersion in zinc electrolyte with MnO4-, the anode Pb-0.72%Ag had the best corrosion resistance, followed by anodes Pb-0.67%Ag, Pb-0.60%Ag, then the close anodes Pb-0.58%Ag and Pb-0.29%Ag-0.1%Ca by the electrochemical impedance spectroscopy （EIS） analysis.
基金Supported by the National Key Research and Development Program of China(2017YFD0300302)the earmarked fund for China Agriculture Research System(CARS-02-25)+1 种基金the Science and Technology Program of the Sixth Division of Xinjiang Production and Construction Corps in China(1703)the Agricultural Science and Technology Innovation Project of the Chinese Academy of Agricultural Sciences.
文摘The accurate evaluation of maize stalk lodging resistance in different growth periods enables timely management of lodging risks and ensures stable and high maize yields.Here,we established five diferent sowing dates to create diferent conditions for maize growth.We evaluated the effects of the different growth conditions on lodging resistance by determining stalk morphology,moisture content,mechanical strength and dry matter,and the relationship between stalk breaking force and these indicators during the silking stage(R1),milk stage(R3),physiological maturity stage(R6),and 20 days after R6.Plant height at R1 positively affected stalk breaking force.At R3,the cofficient of ear height and the dry weight per unit length of basal internodes were key indicators of stalk lodging resistance.At R6,the key indicators were the coefficient of the center of gravity height and plant fresh weight.After R6,the key indicator was the coefficient of the center of gravity height.The crushing strength of the fourth internode correlated significanty and positively with the stalk breaking force from R1 to R6,which indicates that crushing strength is a reliable indicator of stalk mechanical strength.These results suggest that high stalk strength and low ear height beneft lodging resistance prior to R6.During and after R6,the cofficient of the center of gravity height and the mechanical strength of basal internodes can be used to evaluate plant lodging resistance and the appropriate time for harvesting in fields with a high lodging risk.
基金supported by the National Key R&D Program of China (Grant No. 2017YF0605004)the National Natural Science Foundation of China (Grant No. 41675069)the Climate Change Specific Fund of China (Grant No. CCSF201731)
文摘Future changes in the 50-yr return level for temperature and precipitation extremes over China's Mainland are investigated based on a CMIP5 multi-model ensemble for RCP2.6, RCP4.5 and RCP8.5 scenarios. The following indices are analyzed： TXx and TNn （the annual maximum and minimum of daily annual maximum consecutive 5-day precipitation） and CDD maximum and minimum surface temperature）, RX5day （the （maximum annual number of consecutive dry days）. After first validating the model performance, future changes in the 50-yr return values and return periods for these indices are investigated along with the inter-model spread. Multi-model median changes show an increase in the 50-yr return values of TXx and a decrease for TNn, more specifically, by the end of the 21st century under RCP8.5, the present day 50-yr return period of warm events is reduced to 1.2 yr, while extreme cold events over the country are projected to essentially disappear. A general increase in RX5day 50-yr return values is found in the future. By the end of the 21st century under RCP8.5, events of the present RX5day 50-yr return period are projected to reduce to 〈 10 yr over most of China. Changes in CDD-50 show a dipole pattern over China, with a decrease in the values and longer return periods in the north, and vice versa in the south. Our study also highlights the need for further improvements in the representation of extreme events in climate models to assess the future risks and engineering design related to large-scale infrastructure in China.
基金China Postdoctoral Science Foundation ( No20060400826)
文摘Aiming at the uniform features of acceleration response spectra, two scalar periods-the response spectral predominant period Tp and the smoothed spectral predominant period To are employed to normalize the abscissa of the normalized response spectra （NRS） of ground motions, respectively. Engineering characteristics of 5% -damped NRS, and the bi-normalized response spectra （BNRS） are investigated accounting for the effects of soil condition and fault distance. Nearly 600 horizontal ground motion components during the Chi-Chi earthquake are included in the analysis. It shows that the NRS strongly depends on soil condition and fault distance. However, soil condition and distance have only a slight influence on two kinds of BNRS. Dispersion analysis indicates that such normalization can reduce scatter in the derivation of response spectral shapes. Finally, a parametric analysis of the scalar periods （Tp, To） is performed and then compared with those of previous studies. These special and particular aspects of earthquake response spectra and scalar periods need to be considered in developing earthquake-resistant design criteria.
基金National Science and Technology Pillar Program, No.2012BAH48F01 Chinese Academy of Sciences Visiting Professorship for Senior International Scientists, No.2013T2Z0004+1 种基金 National Natural Science Foundation of China, No.41171165 No.41301204
文摘This study applies ArcGIS to analyze the spatiotemporal distribution of cultural sites in the Ill River Valley in northwestern China. It explores relationships between the sites＇ spatiotemporal evolutionary characteristics, human history, and the natural environment. The results indicate that the numbers and proportions of the sites, and the frequency of their oc- currence, exhibited an inverted V-shaped change trend during six historical periods. The ＂high in the east and low in the west＂ spatial distribution pattern of the first three periods shifted to the one the ＂high in the west and low in the east＂ during the latter three periods, demonstrating a change in the spatial center of gravity of human activities. The sites were mainly distributed on slopes of grades 1-5, with their proportions increasing from 75% during the Spring and Autumn Period （770 BC-476 BC）-Qin Dynasty （221 BC-207 BC） to 93.75% during the Qing Dynasty-Modern period. The concentrated distribution of site elevations shifted from grades 4-8 during the Spring and Autumn Period-Qin Dynasty, and the Western Han （206 BC-8）-Southern and Northern Dynasties （420-589）, to grades 1-4 during the latter three periods. The number of sites showed a shifting trend from high-elevation mountains and hills to low-elevation plains, and from high slopes to low slopes. In particular, the sites exhibited a special ＂moist＂ evolutionary pattern of migration from middle and upstream areas to downstream areas, as opposed to the migration pattern of sites located in typical arid areas. The study also considered factors influencing the distribution and spatiotemporal evolution of cultural sites, notably, human factors and natural factors.
基金supported by the National Natural Science Foundation of China(Grants No.51190094,50909073,and 51179130)the Hubei Province Natural Science Foundation(Grant No.2010CDB08401)
文摘The weights of the drought risk index （DRI）, which linearly combines the reliability, resiliency, and vulnerability, are difficult to obtain due to complexities in water security during drought periods. Therefore, drought entropy was used to determine the weights of the three critical indices. Conventional simulation results regarding the risk load of water security during drought periods were often regarded as precise. However, neither the simulation process nor the DRI gives any consideration to uncertainties in drought events. Therefore, the Dempster-Shafer （D-S） evidence theory and the evidential reasoning algorithm were introduced, and the DRI values were calculated with consideration of uncertainties of the three indices. The drought entropy and evidential reasoning algorithm were used in a case study of the Haihe River Basin to assess water security risks during drought periods. The results of the new DRI values in two scenarios were compared and analyzed. It is shown that the values of the DRI in the D-S evidence algorithm increase slightly from the original results of Zhang et al. （2005）, and the results of risk assessment of water security during drought periods are reasonable according to the situation in the study area. This study can serve as a reference for further practical application and planning in the Haihe River Basin, and other relevant or similar studies.
基金the National Natural Science Foundation of China (No.60674043)
文摘In this paper, we present an interval model of networked control systems with time-varying sampling periods and time-varying network-induced delays and discuss the problem of stability of networked control systems using Lyapunov stability theory. A sufficient stability condition is obtained by solving a set of linear matrix inequalities. In the end, the illustrative example demonstrates the correctness and effectiveness of the proposed approach.
基金Supported by the National Natural Science Foundation of China (No.30400333)the National Key Program of Science and Technology of China (2006BAD09A01)
文摘Estivation, hibernation, and starvation are indispensable inactive states of sea cucumbers Apostichopusjaponicus in nature and in culture ponds. Generally, temperature is the principal factor that induces estivation or hibernation in the sea cucumber. The present study provided insight into the physiological adaptations ofA. japonicus during the three types of inactivity （hibernation, estivation, and starvation） by measuring the oxygen consumption rates （Vo2） and biochemical compositions under laboratory conditions of low （3℃）, normal （17℃） and high （24℃） temperature. The results show that the characteristics of A. japonicus in dormancy （hibernation and estivation） states were quite different from higher animals, such as fishes, amphibians, reptiles, and mammals, but more closely resembled a semi-dormant state. It was observed that the shift in the A. japonicus physiological state from normal to dormancy was a chronic rather than acute process, indicated by the gradual depression of metabolic rate. While metabolic rates declined 44.9% for the estivation group and 71.7% for the hibernation group, relative to initial rates, during the 36 d culture period, metabolic rates were not maintained at constant levels during these states. The metabolic depression processes for sea cucumbers in hibernation and estivation appeared to be a passive and an active metabolic suppression, respectively. In contrast, the metabolic rates （128.904-11.70 μg/g h） of estivating sea cucumbers were notably higher （107.85±6.31 μg/gh） than in starving sea cucumbers at 17℃, which indicated that the dormancy mechanism here, as a physiological inhibition, was not as efficient as in higher animals. Finally, the principle metabolic substrate or energy source of sea cucumbers in hibernation was lipid, whereas in estivation they mainly consumed protein in the early times and both protein and lipid thereafter.
基金supported by the Program of Accurate Identification and Display of Soybean Germplasm, China (NB08-2130315-(25-31)-06, NB07-2130315-(25-30)-06, NB06-070401-(22-27)-05), NB2010-2130315-25-05)the National Crop Germplasm Platform, Ministry of Agriculture and Ministry of Science and Technology, China (2012-004, 2014-004)
文摘The growth periods（GPs, from planting/emergence to reproductive stage 8（R8） of soybean cultivars vary in different ecological regions, especially in China with a very complex soybean cropping system. In this study, a 3-yr experimental study was undertaken in three geographical locations of China from 2008 to 2010, including the Northeast（40.66-45.85°N）, Huang-Huai（34.75-38.04°N） and southern（22.82-30.60°N） eco-regions with about 250 accessions in each region to clarify the classification of maturity group（MG） and identify the cultivars with stable GP to increase the knowledge about the GP distribution of soybean cultivars in China. GPs of soybean cultivars in different eco-regions were significant different with a gradual decrease from 115-125 d in the Northeast part to the 85-100 d in the southern part of China. The geographical location was the major factor for GP of cultivars from the Northeast, while the year of planting was the major factor affecting the stability of GPs in Huang-Huai summer and southern summer soybean. AMMI2（additive main effects and multiplicativeinteraction）-Biplot analysis showed that the GPs of soybean cultivars from the Northeast eco-region have a comparatively satisfactory environmental stability. Moreover, soybean cultivars with moderate GP/MG and stable environment adaptability in different eco-regions were identified based on the linear regression and AMMI analysis, which was important for the accurate classification of soybean MGs in future. Taken together, our results reflected the genetic diversity, geographical distribution and environmental stability of the Chinese soybean GP trait. Soybean cultivars with stable GP for various Chinese eco-regions would be beneficial for Chinese soybean genetic improvement, varietal introduction, exchange, and soybean breeding program for wide adaptability.
基金supported by the National Key R&D Program of China (No. 2016YFC0202705)the National Natural Science Foundation of China (Nos. 51638001 and 51478017)the funding support from Beijing Municipal Commission of Science and Technology (Nos. Z161100004516013 and Z171100002217002)
文摘SO_4^(2-) and NO_3^- are important chemical components of fine particulate matter(PM_(2.5)),especially during haze periods.This study selected two haze episodes in Beijing,China with similar meteorological conditions.A monitoring-modeling approach was developed to estimate the secondary conversion ratios of sulfur and nitrogen based on monitored and simulated concentrations.Measurements showed that in Episode 1(24th–25th October,2014),the concentrations(proportions)of SO_4^(2-) and NO_3^- reached 35.1μg/m^3(14.9%) and 55.0μg/m^3(22.9%),while they reached 14.4μg/m^3(9.3%) and 59.1μg/m^3(38.1%)in Episode 2(26th–27th October,2017).A modeling system was applied to apportion Beijing's SO_4^(2-) and NO_3^- in primary and secondary SO_4^(2-)/NO_3^- emitted from local and regional sources.Thus,secondary conversion contributions considering the local and regional level were defined.The former primarily focused on Beijing atmospheric oxidation ability and the latter mainly considered the existence form of Beijing SO_4^(2-)/NO_3^- under the regional transport impacts.Finally,secondary oxidation ratios were estimated through combining secondary conversion contribution coefficients for simulated and monitored concentrations.At regional level,sulfur oxidation ratios in polluted(clean)days during two sampling periods were0.57–0.72(0.07–0.52)and 0.74–0.80(0.08–0.61),nitrogen oxidation ratios were 0.20–0.29(0.05–0.15)and 0.34–0.38(0.02–0.29),indicating that atmospheric oxidation was enhanced when considering regional transport through 2014–2017.At the local level,sulfur oxidation ratios were 0.66–0.71(0.04–0.48)in haze(clean)days,while nitrogen oxidation ratios were0.16–0.29(0.02–0.16).The atmospheric oxidation ability markedly increased in PM_(2.5)pollution days,but changed only slightly between the two periods.
基金Supported by Construction Project of National Rapeseed Modern Industrial Technology System (nycytx-00563)Guizhou Academy of Agricultural Sciences "Research of High Yield and High Quality Cultivation Technology for High Grade Hybrid Rapeseed with High Oil" [C ZX(2007)015]+2 种基金Department of Agriculture of Guizhou Province "Research, Promotion and Application of High Yield Cultivation Technology for Hybridized Rapeseed of New Variety Youyan 599" [QNYZZ (2009) 007]Guizhou Academy of Agricultural Sciences "Large Area Intermediate Experiment, Promotion and Application of Hybridized Rapeseed Youyan 599" [QNKZX (2009) 030]Department of Agriculture of Guizhou Province "Integrated Innovation of Seed Production Techniques and Large Area Demonstration for New High Oil Rapeseed Hybrid Variety Sanbei 98 [QKH NY (2010) 3087]~~
文摘[Objective] The paper was to study the nitrogen application amount and nitrogen application model for high grade hybrid rapeseed （Brassica napus L.） to get high yield. [Method] With ＂Youyan 599＂ and ＂Sanbei 98＂ as materials, using quadratic regression orthogonal gyration combination design, the impact of nitrogen application amount during various periods on rapeseed yield was studied. [Result] The combinations of factors to obtain the highest yield index （2 898.211 kg / hm 2 ） of ＂Youyan 599＂ were as follows： living rape fertilizer 89.27 kg / hm 2 , opening fertilizer 120 kg / hm 2 , 12 th lunar month fertilizer 101.12 kg / hm 2 , total nitrogen application amount 310.39 kg / hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12th lunar month fertilizer were 28.76%, 38.66% and 32.58%, respectively. The combinations of factors to obtain the highest yield index （2 870.14 kg/hm 2 ） of ＂Sanbei 98＂ were as follows： living rape fertilizer 120 kg / hm 2 , opening fertilizer 120 kg / hm 2 , 12 th lunar month fertilizer 37.55kg / hm 2 , total nitrogen application amount 277.55 kg / hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12 th lunar month fertilizer were 43.24%, 43.24% and 13.53%, respectively. The combinations of factors to obtain the highest yield index of two combined varieties （2 813.82 kg/hm 2 ）were as follows： living rape fertilizer 120 kg/hm 2 , opening fertilizer 120 kg/hm 2 , 12 th lunar month fertilizer 76.23 kg/hm 2 , total nitrogen application amount 316.23 kg/hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12 th lunar month fertilizer were 37.95% , 37.95% and 24.11% , respectively. [Conclusion] The paper provided theoretical basis for high yield cultivation of high grade hybridized rapeseed.
基金Project supported by the National Science Fund for Distinguished Young Scholars,China(No.40325001)the National Basic Research and Development Program of China(No.2002CB410805)the Asia-Link Program(No.CN/AsiaLink/001(81468)).
文摘A batch experiment was performed to investigate nonequilibrium adsorption behavior of atrazine （2-chloro-4-ethylamino-6-isopropylamlno-1,3,5-triazlne） on a fluvo-aquic soil. The amount of atrazine sorbed increased with increasing adsorption contact periods. For a range of initial atrazlne concentrations, the percentage of atrazine sorbed within 24 h ranged from 24% to 77% of the observed total amount sorbed for the longest contact period; when adsorption contact periods were more than 72 h, the deviations in curves fitted using a nonlinear Freundllch equation gradually became less. The opposite trend was observed for the atrazine concentrations in solution. The effect of adsorption contact periods on atrazine adsorption behavior was evaluated by interpreting the temporal variations in linear and nonlinear Freundlich equation parameters obtained from the phase-distribution relationships. As the adsorption contact period increased, the nonlinear Freundlich capacity coefficient kf showed a significant linear increase （r^2 = 0.9063, P 〈 0.001）. However, a significant negative linear correlation was observed for the nonlinear coefficient n, a dimensionless parameter （r^2 = 0.5666, P 〈 0.05）. Furthermore, the linear distribution coefficient kd ranged from 0.38 to 1.44 and exhibited a significant linear correlation to the adsorption contact period （r^2 = 0.72, P 〈 0.01）. The parameters kf and n obtained from a time-dependent isotherm rather than the distribution coefficient kd estimated using the linear Freundlich equation were more appropriate to predict the herbicide residue in the field and thus more meaningful for environmental assessment.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA050800)the Key Program of the Chinese Academy of Sciences (Grant No. KJZD-EW-TZ-G10)the National Natural Science Foundation of China (Grant No.41671201 and 91525101)
文摘This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation in China has exhibited significant 50–70-yr, 100–120-yr, and 200–250-yr cycles. Results also show that the amplitudes of decadal and centennial temperature variation were 1.3℃ and 0.7℃, respectively, with the latter significantly correlated with long-term changes in solar radiation, especially cold periods, which correspond approximately to sunspot minima. The most rapid warming in China occurred over AD 1870–2000, at a rate of 0.56°± 0.42℃（100 yr）^（-1）; however, temperatures recorded in the 20 th century may not be unprecedented for the last 2000 years, as data show records for the periods AD 981–1100 and AD1201–70 are comparable to the present. The ensemble means of dryness/wetness spatial patterns in eastern China across all centennial warm periods illustrate a tripole pattern： dry south of 25°N, wet from 25°–30°N, and dry to the north of 30°N. However, for all centennial cold periods, this spatial pattern also exhibits a meridional distribution. The increase in precipitation over the monsoonal regions of China associated with the 20 th century warming can primarily be attributed to a mega El Nino–Southern Oscillation and the Atlantic Multidecadal Oscillation. In addition, a significant association between increasing numbers of locusts and dry/cold conditions is found in eastern China. Plague intensity also generally increases in concert with wetness in northern China, while more precipitation is likely to have a negative effect in southern China.
基金Supported by Guizhou Province Science and Technology Major Project(Qiankehe Major Special Project[2019]3007-6)Guizhou Province Science and Technology Support Plan Project(Qiankehe Support[2019]2773)Guizhou Province Reform and Transformation Plan Project(Qiankehe Z Word[2013]4006)。
文摘In this study,Cordyceps militaris strain QC04 was cultivated in oat,rice,and wheat media for different time periods.We studied the effects of different cultivation media and periods on the fruiting body biomass and active components of C.militaris,aiming to provide reference for the production and utilization of C.militaris QC04.The results showed that the dry weight of the fruiting body of C.militaris was the highest in the wheat medium,moderate in the oat medium,and the lowest in the rice medium.The content of cordycepin and adenosine in the fruiting body and residual medium was higher in the oat and rice media than in the rice medium.The content of cordycepin and adenosine in fruiting body and residual medium peaked on day 55.Furthermore,the content of cordycepin in the fruiting body was lower than that in the residual medium,while the content of adenosine showed an opposite trend.The content of cordycepic acid in the rice medium was generally higher than that in the oat and wheat media.As the cultivation period extended,the fruiting body biomass declined and the content of cordycepic acid in the fruiting body increased slightly.
