The space constellation of the BeiDou navigation satellite system(BDS) is a hybrid constellation containing medium earth orbit(MEO) satellites, geostationary earth orbit(GEO) satellites, and inclined geosynchronous or...The space constellation of the BeiDou navigation satellite system(BDS) is a hybrid constellation containing medium earth orbit(MEO) satellites, geostationary earth orbit(GEO) satellites, and inclined geosynchronous orbit(IGSO) satellites. Due to the geosynchronous characteristics of GEO and IGSO, GEO satellites and IGSO satellites often need to perform orbital maneuvers, which can affect the signal-inspace(SIS) availability performance of BeiDou satellites. A two-step detection method for BeiDou satellite orbital maneuvers has been proposed in this paper. The first step is to identify orbital maneuvers based on time series analysis of broadcast ephemeris, and the second step is to verify orbital maneuvers based on bidirectional orbit prediction. The two-step detection method was used to detect the orbital maneuvers of BeiDou satellites in 2019. Through the double guarantees of identification and verification,the detection accuracy of BeiDou satellite orbital maneuvers has been effectively improved. And the orbital maneuver detection results are continued to be used to assess the SIS availability of BeiDou satellites. The results show that the availability loss of GEO satellite orbital maneuvers is about 0.45%-1.07%, and the availability loss of IGSO satellite orbital maneuvers is about 0.12%-0.19%.展开更多
Nitrogen(N) and phosphorus(P) are two essential mineral nutrients for plant growth,which are required in relative high amount in plants.Plants have evolved a series of strategies for coordinately acquiring and utilizi...Nitrogen(N) and phosphorus(P) are two essential mineral nutrients for plant growth,which are required in relative high amount in plants.Plants have evolved a series of strategies for coordinately acquiring and utilizing N and P.However,physiological and molecular mechanisms underlying of N and P interactions remain largely unclear in soybean(Glycine max).In this study,interactions of N and P were demonstrated in soybean as reflected by significant increases of phosphate(Pi) concentration in both leaves and roots by N deficiency under Pi sufficient conditions.A total of four nitrogen limitation adaptation(NLA),encoding RING-type E3 ubiquitin ligase were subsequently identified in soybean genome.Among them,transcription of Gm NLA1-1 and Gm NLA1-3 was decreased in soybean by N starvation under Pi sufficient conditions,not for Gm NLA1-2.Suppression of all three Gm NLA1 members was able to increase Pi concentration regardless of the P and N availability in the growth medium,but decrease fresh weight under normal conditions in soybean hairy roots.However,comparted to changes in control lines at two N levels,N deficiency only resulted in a relatively higher increase of Pi concentration in Gm NLA1-1 or Gm NLA1-3 suppression lines,strongly indicating that Gm NLA1-1 and Gm NLA1-3 might regulate P homeostasis in soybean response to N starvation.Taken together,our result suggest that redundant and diverse functions present in Gm NLA1 members for soybean coordinate responses to P and N availability,which mediate P homeostasis.展开更多
To achieve the high availability of health data in erasure-coded cloud storage systems,the data update performance in erasure coding should be continuously optimized.However,the data update performance is often bottle...To achieve the high availability of health data in erasure-coded cloud storage systems,the data update performance in erasure coding should be continuously optimized.However,the data update performance is often bottlenecked by the constrained cross-rack bandwidth.Various techniques have been proposed in the literature to improve network bandwidth efficiency,including delta transmission,relay,and batch update.These techniques were largely proposed individually previously,and in this work,we seek to use them jointly.To mitigate the cross-rack update traffic,we propose DXR-DU which builds on four valuable techniques:(i)delta transmission,(ii)XOR-based data update,(iii)relay,and(iv)batch update.Meanwhile,we offer two selective update approaches:1)data-deltabased update,and 2)parity-delta-based update.The proposed DXR-DU is evaluated via trace-driven local testbed experiments.Comprehensive experiments show that DXR-DU can significantly improve data update throughput while mitigating the cross-rack update traffic.展开更多
With the goal of evaluating the wave and wave energy conditions in the Philippines,the simulated wave nearshore(SWAN)model was used to estimate the wavefield using 30 years of cross-calibrated multi-platform(CCMP)wind...With the goal of evaluating the wave and wave energy conditions in the Philippines,the simulated wave nearshore(SWAN)model was used to estimate the wavefield using 30 years of cross-calibrated multi-platform(CCMP)wind field data(1987-2016).The spatiotemporal patterns of annual and monthly averaged significant wave heights and wave energy in the Philippines were analyzed based on the simulated data.Results showed that they had similar values;in particular,significant wave heights and wave energy were smaller in the south and southwest and higher in the north and northeast.A total of 12 representative points along the Philippine coast were selected to draw wave and wave energy roses.A directional analysis showed that the dominant wave was in the north north-east(NNE),northeast(NE),and east north-east(ENE)directions.Wave energy was mainly distributed in regions with an energy period between 1 and 10 s and significant wave heights between 0 and 4 m.To better utilize wave energy data in the Philippines,this paper studied the available and rich area of wave energy and analyzed the annual and monthly variability index of wave energy in the country.Moreover,the available significant wave heights of wave energy conversion devices(WECs)were set as 0.5-4 m,and the maximum annual average available wave energy occurred in the eastern Philippine Sea area,reaching 13 kW m^(-1).For the safety of WECs,extreme typhoon-induced wave conditions must be considered.Furthermore,the results showed that the maximum significant wave height and mean period over the 50-year return period reached 18 m and 15 s,respectively.展开更多
Background: Malaria remains a major cause of morbidity and mortality in Zambia, affecting all levels of society, with children under the age of five and pregnant women being most at risk of serious illness. The availa...Background: Malaria remains a major cause of morbidity and mortality in Zambia, affecting all levels of society, with children under the age of five and pregnant women being most at risk of serious illness. The availability of antimalarial medicines is one of the key interventions of malaria management. This study assessed the availability of antimalarial medicines in community pharmacies in Lusaka district, Zambia. Materials and Methods: This was a cross-sectional study that was conducted among 210 community pharmacies from September to November 2022 using a well-structured checklist in selected areas of Lusaka district. The availability was verified by a physical check of the product. The checklist contained the medicines listed both in the guidelines for diagnosis and treatment of malaria in Zambia as well as in the World Health Organization (WHO) malaria treatment guidelines. Results: This study found that all antimalarials listed in the local treatment guidelines for malaria were available in community pharmacies, though with the varying distribution. Of the 210 community pharmacies, 209 (99.5%) had artemether/lumefantrine in stock. The lowest available antimalarial was quinine/clindamycin, which was only available in 3 (1.4%) of the outlets. Conversely, 3 out of 16 (18.8%) antimalarials that were available in community pharmacies were not listed in the local treatment guidelines of malaria in Zambia, despite being listed in the WHO malaria treatment guidelines. This translated into a compliance level of 81.2% based on the local malaria treatment guidelines. Conclusion: This study concluded that antimalarials were available for all categories of malaria management in community pharmacies, though with a varying distribution. The presence of antimalarials not listed in the Zambian treatment guidelines is of public health concern which may have an impact on antimicrobial resistance in the future.展开更多
This research article is based on a study of optimal frequency to the repairable system due to the failure finding interval to maximize as well as minimize the availability of some components devices. We studied toget...This research article is based on a study of optimal frequency to the repairable system due to the failure finding interval to maximize as well as minimize the availability of some components devices. We studied together maintenance and corrective actions that carried out item of failure and periodic failure finding designed to check whether a system is still working. The model is proved as well as useful application in detecting the problem related to finding failure tasks of different scheme devices by maximization. The model formulated and the numerical application to the relevant mathematical model have been discussed to demonstrate the article quality. Therefore based on probability analytic development, the optimal maintenance policy is then obtained as solution of an optimization problem in which the maintenance cost rate is the objective function and the risk of corrective maintenance is the constraint function. Finally, the solution to the optimal device in the considered development model has been well adjusted due to derivation to the experimental observation rather than theory which will be taken into consideration in the next applied practical design research related and the system device provided that, the proactive device agreed with using the exponential distribution to the survive distribution function which can not be considered as valid.展开更多
One of the ways of overcoming the cost of irrigation is through in-situ water harvesting at the plant roots. Super absorbent polymer (SAP) can facilitate water harvesting at the plant roots. This study attempted to as...One of the ways of overcoming the cost of irrigation is through in-situ water harvesting at the plant roots. Super absorbent polymer (SAP) can facilitate water harvesting at the plant roots. This study attempted to assess the effect of SAP on plant available water (PAW) of different soils. In this study, SAP was sequentially added at the rate of 0.2%, 0.3% and 0.5% of the soil weight and its impact assessed in clay, sandy clay and sandy loam soils. The moisture retention characteristics of the original and SAP treated soils were studied using soil water retention curves (SWRC) and results modelled using Gardner model. PAW was estimated from SWRC as the difference between moisture content at 1.5 and 3 bar in all soils. The difference in PAW between original and treated soils was assessed at 5% level of significance. The WRC of all the samples was adequately found to be described by the Gardner model (Coefficient of determination R<sup>2</sup> ≥ 98% and residual standard error (RSE) ≤ 0.04). SWRC changed with increase in SAP percentage in clay, sandy clay and sandy loam soils. Clay had a higher change in water retention then sandy clay and lastly sandy loam. Plant available water content (PAW) in all soils increased. In clay soil it increased with increase in SAP from 0.3291 at zero SAP to 0.6223 at 0.5% SAP. Sandy clay soil increased in PAW from 0.2721 at zero SAP to 0.5335 at 0.5% SAP and Sandy loam soils from 0.1691 at zero SAP to 0.3461 at 0.5% SAP. Hence, from the study SAP can be used to conserve irrigation water in the plant roots and therefore reducing the cost since PAW has been increased.展开更多
Unified identity authentication has become the basic information service provided by colleges and universities for teachers and students. Security, stability, high concurrency and easy maintenance are our requirements...Unified identity authentication has become the basic information service provided by colleges and universities for teachers and students. Security, stability, high concurrency and easy maintenance are our requirements for a unified identity authentication system. Based on the practical work experience of China University of Geosciences (Beijing), this paper proposes a high availability scheme of unified identity authentication system based on CAS, which is composed of multiple CAS Servers, Nginx for load balancing, and Redis as a cache database. The scheme has been practiced in China University of Geosciences (Beijing), and the application effect is good, which has practical reference significance for other universities.展开更多
All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciati...All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciation and availability. We studied the effects of heavy metal speciation and availability on soil microorganism activities along a Cu/Zn contamination gradient. Microbial biomass and enzyme activity of soil contaminated with both Cu and Zn were investigated. The results showed that microbial biomass was negatively affected by the elevated metal levels. The microbial biomass-C (Cmic)/organic C (Corg) ratio was closely correlated to heavy metal stress. There were negative correlations between soil microbial biomass, phosphatase activity and NH4NO3 extractable heavy metals. The soil microorganism activity could be predicted using empirical models with the availability of Cu and Zn. We observed that 72% of the variation in phosphatase activity could be explained by the NH4NO3-extractable and total heavy metal concentration. By considering different monitoring approaches and different viewpoints, this set of methods applied in this study seemed sensitive to site differences and contributed to a better understanding of the effects of heavy metals on the size and activity of microorganisms in soils. The data presented demonstrate the relationship between heavy metals availability and heavy metal toxicity to soil microorganism along a contamination gradient.展开更多
The available soil water capacity (ASWC) is important for studying crop production, agro-ecological zoning, irrigation planning, and land cover changes. Laboratory determined data of ASWC are often not available for m...The available soil water capacity (ASWC) is important for studying crop production, agro-ecological zoning, irrigation planning, and land cover changes. Laboratory determined data of ASWC are often not available for most of soil profiles and the nationwide ASWC largely remains lacking in relevant soil data in China. This work was to estimate ASWC based on physical and chemical properties and analyze the spatial distribution of ASWC in China. The pedo-transfer functions (PTFs), derived from 220 survey data of ASWC, and the empirical data of ASWC based on soil texture were applied to quantify the ASWC. GIS technology was used to develop a spatial file of ASWC in China and the spatial distribution of ASWC was also analyzed. The results showed the value of ASWC ranges from 15 × 10-2 cm3·cm-3 to 22 × 10-2 cm3·cm-3 for most soil types, and few soil types are lower than 15 × 10-2 cm3·cm-3 or higher than 22 × 10-2 cm3·cm-3. The ASWC is different according to the complex soil types and their distribution. It is higher in the east than that in the west, and the values reduce from south to north except the northeastern part of China. The "high" values of ASWC appear in southeast, northeastern mountain regions and Northeast China Plain. The relatively "high" values of ASWC appear in Sichuan basin, Huang-Huai-Hai plain and the east of Inner Mongolia. The relatively "low" values are distributed in the west and the Loess Plateau of China. The "very low" value regions are the northern Tibetan Plateau and the desertified areas in northern China. In some regions, the ASWC changes according to the complex topography and different types of soils. Though there remains precision limitation, the spatial data of ASWC derived from this study are improved on current data files of soil water retention properties for Chinese soils. This study presents basic data and analysis methods for estimation and evaluation of ASWC in China.展开更多
A new methodology for multi-step-ahead forecasting was proposed herein which combined the wavelet transform(WT), artificial neural network(ANN) and forecasting strategies based on the changing characteristics of avail...A new methodology for multi-step-ahead forecasting was proposed herein which combined the wavelet transform(WT), artificial neural network(ANN) and forecasting strategies based on the changing characteristics of available parking spaces(APS). First, several APS time series were decomposed and reconstituted by the wavelet transform. Then, using an artificial neural network, the following five strategies for multi-step-ahead time series forecasting were used to forecast the reconstructed time series: recursive strategy, direct strategy, multi-input multi-output(MIMO) strategy, DIRMO strategy(a combination of the direct and MIMO strategies), and newly proposed recursive multi-input multi-output(RECMO) strategy which is a combination of the recursive and MIMO strategies. Finally, integrating the predicted results with the reconstructed time series produced the final forecasted available parking spaces. Three findings appear to be consistently supported by the experimental results. First, applying the wavelet transform to multi-step ahead available parking spaces forecasting can effectively improve the forecasting accuracy. Second, the forecasting resulted from the DIRMO and RECMO strategies is more accurate than that of the other strategies. Finally, the RECMO strategy requires less model training time than the DIRMO strategy and consumes the least amount of training time among five forecasting strategies.展开更多
Eremosparton songoricum (Litv.) Vass is a dwarf clonal shrubby legume developed on the windward slopes of mobile or semi-fixed sand dunes of Central Asia. It is assumed that E. songoricum must possess a high degree ...Eremosparton songoricum (Litv.) Vass is a dwarf clonal shrubby legume developed on the windward slopes of mobile or semi-fixed sand dunes of Central Asia. It is assumed that E. songoricum must possess a high degree of phenotypic plasticity for such a heterogeneous habitat. The variations of E. songoricum plants growing in two typical microhabitats (the upper slope and the lower slope of semi-mobile dune) were investigated. The morphological characteristics and the biomass allocation patterns were measured and compared at the clonal fragment level. Compared with the clonal fragment on the lower slope of dune, the clonal fragment on the upper slope of the dune (a) declined in total biomass and ramet height, (b) increased the length of rhizomes and the number of roots, (c) increased the degree of asym- metry, and (d) heightened allocation to the belowground biomass. Our results confirmed the hypothesis of high phenotypic adjustment capacity of E. songoricum to habitat moisture availability. Phenotypic plasticity of E. songoricum contributed to reduce the damage risk, led to an environmentally induced specialization in function of resources exploitation, resulted in its persistence in heterogeneous environments and was adaptive in sand dune environment.展开更多
Typical sediments from Taihu Lake, a meso-to-hypereutrophic lake, were collected and examined on the basis of P-fractionation by sequential extraction scheme. Sedimentary inorganic phosphorus were fractioned into four...Typical sediments from Taihu Lake, a meso-to-hypereutrophic lake, were collected and examined on the basis of P-fractionation by sequential extraction scheme. Sedimentary inorganic phosphorus were fractioned into four forms and the rank order according to the mean concentration of P-fractions in Taihu Lake was NaOH-P>BD-P>HCl-P>NH_4Cl-P. The concentrations of BD-P were linearly correlated with the content of active Fe(R2=0.96). Also, the linear relationship between the sum of BD-P and NaOH-P and the sum of active Fe and active Al content was observed within the six sediments investigated(R2=0.96). Moreover, the bio-available phosphorus(BAP) content was estimated by the sum of NH_4Cl-P, BD-P, and NaOH-P, viz. BAP=NH_4Cl-P+NaOH-P+BD-P. In Taihu Lake, the BAP contents are ranging from 0.10 mg/g dw to 1.25 mg/g dw, and average 0.40 mg/g dw for all sediment samples. The relative contributions of BAP to total sedimentary phosphorus(TP) and inorganic sedimentary phosphorus(IP) range from 18.67% to 50.79%(33.61% on average) and from 52.82% to 82.09%(67.81% on average), respectively.展开更多
The availability of three dissolved organic phosphorus (DOP) compounds as nutrient sources for experimentalcultare of three algae was studied. Results indicated that these compounds could be utilized byalgae, and th...The availability of three dissolved organic phosphorus (DOP) compounds as nutrient sources for experimentalcultare of three algae was studied. Results indicated that these compounds could be utilized byalgae, and that dissolved inorganic phosphorus (DIP) was first to be uptaken when various forms ofphosphorus (DIP and DOP) co-existed. Dicrateria zhanjiangensis’ uptake of sodium glycerophosphatewas faster than that of D-ribose-5-phosphate. The increase of sodium glycerphosphate had little effecton the maximum uptake rate(V<sub>max</sub>) of Chlorella sp., but increased the semisaturation constant(K<sub>s</sub>) remarkably;the photosynthesis rates(PR) of Dicrateria zhanjiangensis and Chlorella sp. were rarely affected byusing various forms of phosphorus in the culture experiments. The possible DOP pathways utilizedby algae are discussed.展开更多
Soil with low phosphorus (P) availability and organic matter contents exists in large area of southwest of China, but some soybean genotypes still show well adaptations to this low yield farmland. However, to date, th...Soil with low phosphorus (P) availability and organic matter contents exists in large area of southwest of China, but some soybean genotypes still show well adaptations to this low yield farmland. However, to date, the underlying mechanisms of how soybean regulates soil P availability still remains unclear, like microbe-induced changes. The objective of the present study was to compare the differences of rhizosphere bacterial community composition between E311 and E109 in P-sufficiency (10.2 mg kg^-1) and P-insufficiency (5.5 mg kg^-1), respectively, which then feedback to soil P availability. In P-sufficiency, significant differences of the bacterial community composition were observed, with fast-growth bacterial phylum Proteobacteria, genus Dechloromonas, Pseudomonas, Massilia, and Propionibacterium that showed greater relative abundances in E311 compared to E109, while in P-insufficiency were not. A similar result was obtained that E311 and E109 were clustered together in P-insufficiency rather than in P-sufficiency by using principal component analysis and hierarchical clustering analysis. The quadratic relationships between bacterial diversity and soil P availability in rhizosphere were analyzed, confirming that bacterial diversity enhanced the soil P availability. Moreover, the high abundance of Pseudomonas and Massilia in the rhizosphere of E311 might increased the P availability. In the present study, the soybean E311 showed capability of shaping rhizosphere bacterial diversity, and subsequently, increasing soil P availability. This study provided a strategy for rhizosphere management through soybean genotype selection and breeding to increase P use efficiency, or upgrade middle or low yield farmland.展开更多
Background:Flammulina velutipes stem waste(FVS)is the by-product of mushroom industry.The objectives of this study were to determine the available energy and amino acid digestibility of FVS fed to pigs,and to evaluate...Background:Flammulina velutipes stem waste(FVS)is the by-product of mushroom industry.The objectives of this study were to determine the available energy and amino acid digestibility of FVS fed to pigs,and to evaluate the effects of dietary FVS inclusion on growth performance,biochemical profile of serum,fecal short chain fatty acid(SCFA)concentration,carcass traits,meat quality,intestinal morphology and microflora of pigs.In Exp.1,twelve crossbred barrows with initial body weight(IBW)of 37.48±4.31 kg were randomly allotted to 2 dietary treatments,including a corn basal diet and an experimental diet containing 24.35%FVS.In Exp.2,twelve barrows fitted with an ileal T-cannula(IBW:32.56±1.67 kg)were randomly allotted to 2 dietary treatments,which included a N-free diet and an experimental diet containing 40.0%FVS.In Exp.3,ninety growing pigs(IBW:63.98±6.89 kg)were allotted to 1 of 3 treatment diets for 63 d,including a basal diet and 2 experimental diets with 2.5%and 5%FVS,respectively.Results:The digestible energy(DE)and metabolizable energy(ME)of FVS were 4.58 and 4.06 MJ/kg on dry matter basis,respectively,and the standardized ileal digestibility(SID)of indispensable AAs ranged from 17.50%to 59.47%.Pigs fed diets with 2.5%FVS showed no difference on average daily gain(ADG)and gain to feed ratio(G/F).Although dietary 5%FVS inclusion impaired apparent total tract digestibility(ATTD)of organic matter and gross energy,it elevated the SCFA concentration(P≤0.04)in gut and antioxidant capacity in serum.In addition,dietary FVS inclusion depressed the backfat thickness(P=0.03)in pigs.The longissimus dorsi muscle of pigs fed FVS revealed higher n-3 polyunsaturated fatty acid concentration and optimized fatty acid composition.Dietary 2.5%FVS inclusion also improved the intestinal development and health by increasing the villius height to crypt depth ratio(V/C)in jejunum(P<0.01),and promoting microbial diversity and beneficial microbiota proliferation.Conclusions:It is feasible to include moderate content of FVS as an unconventional fiber ingredient in diet of growingfinishing pigs.展开更多
This paper considers a project scheduling problem with the objective of minimizing resource availability costs appealed to finish al activities before the deadline. There are finish-start type precedence relations amo...This paper considers a project scheduling problem with the objective of minimizing resource availability costs appealed to finish al activities before the deadline. There are finish-start type precedence relations among the activities which require some kinds of renewable resources. We predigest the process of sol-ving the resource availability cost problem (RACP) by using start time of each activity to code the schedule. Then, a novel heuris-tic algorithm is proposed to make the process of looking for the best solution efficiently. And then pseudo particle swarm optimiza-tion (PPSO) combined with PSO and path relinking procedure is presented to solve the RACP. Final y, comparative computational experiments are designed and the computational results show that the proposed method is very effective to solve RACP.展开更多
The new model for parallel repairable system is introduced, and it is based on the practice problems of maintenance and the idea of Ion-Channel modeling. In the new model, repair times that are sufficiently short (le...The new model for parallel repairable system is introduced, and it is based on the practice problems of maintenance and the idea of Ion-Channel modeling. In the new model, repair times that are sufficiently short (less than some critical value) do not result in system failure, and such a repair interval is omitted from the downtime record. Usually, the underlying process is Markov process if the durations of working and repair time have the negative-exponential distributions, but the new system has not the Markov properties, which is worth to study. The reliability indexes such as instantaneous availability and steady-state availabilities for the new system are given through probability analysis. A numerical example is given to illustrate the results.展开更多
Short-term nitrous oxide(N2O) pulse emissions caused by precipitation account for a considerable portion of the annual N2O emissions and are greatly influenced by soil nitrogen(N) dynamics. However, in Chinese sem...Short-term nitrous oxide(N2O) pulse emissions caused by precipitation account for a considerable portion of the annual N2O emissions and are greatly influenced by soil nitrogen(N) dynamics. However, in Chinese semiarid temperate steppes, the response of N2O emissions to the coupling changes of precipitation and soil N availability is not yet fully understood. In this study, we conducted two 7-day field experiments in a semiarid temperate typical steppe of Inner Mongolia, China, to investigate the N2O emission pulses resulting from artificial precipitation events(approximately equivalent to 10.0 mm rainfall) under four N addition levels(0, 5, 10 and 20 g N/(m2·a)) using the static opaque chamber technique. The results show that the simulated rainfall during the dry period in 2010 caused greater short-term emission bursts than that during the relatively rainy observation period in 2011(P〈0.05). No significant increase was observed for either the N2O peak effluxes or the weekly cumulative emissions(P〉0.05) with single water addition. The peak values of N2O efflux increased with the increasing N input. Only the treatments with water and medium(WN10) or high N addition(WN20) significantly increased the cumulative N2O emissions(P〈0.01) in both experimental periods. Under drought condition, the variations in soil N2O effluxes were positively correlated with the soil NH4-N concentrations in the three N input treatments(WN5, WN10, and WN20). Besides, the soil moisture and temperature also greatly influenced the N2O pulse emissions, particularly the N2O pulse under the relatively rainy soil condition or in the treatments without N addition(ZN and ZWN). The responses of the plant metabolism to the varying precipitation distribution and the length of drought period prior to rainfall could greatly affect the soil N dynamics and N2O emission pulses in semiarid grasslands.展开更多
基金This research was funded by the Shandong Provincial Natural Science Foundation(ZR2022QD100,ZR2022QE221)the Weifang University of Science and Technology Doctoral Research Startup Fund(2021KJBS16).
文摘The space constellation of the BeiDou navigation satellite system(BDS) is a hybrid constellation containing medium earth orbit(MEO) satellites, geostationary earth orbit(GEO) satellites, and inclined geosynchronous orbit(IGSO) satellites. Due to the geosynchronous characteristics of GEO and IGSO, GEO satellites and IGSO satellites often need to perform orbital maneuvers, which can affect the signal-inspace(SIS) availability performance of BeiDou satellites. A two-step detection method for BeiDou satellite orbital maneuvers has been proposed in this paper. The first step is to identify orbital maneuvers based on time series analysis of broadcast ephemeris, and the second step is to verify orbital maneuvers based on bidirectional orbit prediction. The two-step detection method was used to detect the orbital maneuvers of BeiDou satellites in 2019. Through the double guarantees of identification and verification,the detection accuracy of BeiDou satellite orbital maneuvers has been effectively improved. And the orbital maneuver detection results are continued to be used to assess the SIS availability of BeiDou satellites. The results show that the availability loss of GEO satellite orbital maneuvers is about 0.45%-1.07%, and the availability loss of IGSO satellite orbital maneuvers is about 0.12%-0.19%.
基金supported by the National Key Research and Development Program of China (2021YFF1000500)Major Program of Guangdong Basic and Applied Research (2019B030302006)+2 种基金the National Natural Science Foundation of China (32172659,32172658, 31872164)the STIC Grant (SGDX20210823103535007)the Natural Science Foundation of Guangdong Province of China(2021A1515010826, 2020A1515110261)。
文摘Nitrogen(N) and phosphorus(P) are two essential mineral nutrients for plant growth,which are required in relative high amount in plants.Plants have evolved a series of strategies for coordinately acquiring and utilizing N and P.However,physiological and molecular mechanisms underlying of N and P interactions remain largely unclear in soybean(Glycine max).In this study,interactions of N and P were demonstrated in soybean as reflected by significant increases of phosphate(Pi) concentration in both leaves and roots by N deficiency under Pi sufficient conditions.A total of four nitrogen limitation adaptation(NLA),encoding RING-type E3 ubiquitin ligase were subsequently identified in soybean genome.Among them,transcription of Gm NLA1-1 and Gm NLA1-3 was decreased in soybean by N starvation under Pi sufficient conditions,not for Gm NLA1-2.Suppression of all three Gm NLA1 members was able to increase Pi concentration regardless of the P and N availability in the growth medium,but decrease fresh weight under normal conditions in soybean hairy roots.However,comparted to changes in control lines at two N levels,N deficiency only resulted in a relatively higher increase of Pi concentration in Gm NLA1-1 or Gm NLA1-3 suppression lines,strongly indicating that Gm NLA1-1 and Gm NLA1-3 might regulate P homeostasis in soybean response to N starvation.Taken together,our result suggest that redundant and diverse functions present in Gm NLA1 members for soybean coordinate responses to P and N availability,which mediate P homeostasis.
基金supported by Major Special Project of Sichuan Science and Technology Department(2020YFG0460)Central University Project of China(ZYGX2020ZB020,ZYGX2020ZB019).
文摘To achieve the high availability of health data in erasure-coded cloud storage systems,the data update performance in erasure coding should be continuously optimized.However,the data update performance is often bottlenecked by the constrained cross-rack bandwidth.Various techniques have been proposed in the literature to improve network bandwidth efficiency,including delta transmission,relay,and batch update.These techniques were largely proposed individually previously,and in this work,we seek to use them jointly.To mitigate the cross-rack update traffic,we propose DXR-DU which builds on four valuable techniques:(i)delta transmission,(ii)XOR-based data update,(iii)relay,and(iv)batch update.Meanwhile,we offer two selective update approaches:1)data-deltabased update,and 2)parity-delta-based update.The proposed DXR-DU is evaluated via trace-driven local testbed experiments.Comprehensive experiments show that DXR-DU can significantly improve data update throughput while mitigating the cross-rack update traffic.
基金The study was supported by the National Natural Science Foundation of China–Shandong Joint Fund(No.U1706226)the National Natural Science Foundation of China(No.52171284).
文摘With the goal of evaluating the wave and wave energy conditions in the Philippines,the simulated wave nearshore(SWAN)model was used to estimate the wavefield using 30 years of cross-calibrated multi-platform(CCMP)wind field data(1987-2016).The spatiotemporal patterns of annual and monthly averaged significant wave heights and wave energy in the Philippines were analyzed based on the simulated data.Results showed that they had similar values;in particular,significant wave heights and wave energy were smaller in the south and southwest and higher in the north and northeast.A total of 12 representative points along the Philippine coast were selected to draw wave and wave energy roses.A directional analysis showed that the dominant wave was in the north north-east(NNE),northeast(NE),and east north-east(ENE)directions.Wave energy was mainly distributed in regions with an energy period between 1 and 10 s and significant wave heights between 0 and 4 m.To better utilize wave energy data in the Philippines,this paper studied the available and rich area of wave energy and analyzed the annual and monthly variability index of wave energy in the country.Moreover,the available significant wave heights of wave energy conversion devices(WECs)were set as 0.5-4 m,and the maximum annual average available wave energy occurred in the eastern Philippine Sea area,reaching 13 kW m^(-1).For the safety of WECs,extreme typhoon-induced wave conditions must be considered.Furthermore,the results showed that the maximum significant wave height and mean period over the 50-year return period reached 18 m and 15 s,respectively.
文摘Background: Malaria remains a major cause of morbidity and mortality in Zambia, affecting all levels of society, with children under the age of five and pregnant women being most at risk of serious illness. The availability of antimalarial medicines is one of the key interventions of malaria management. This study assessed the availability of antimalarial medicines in community pharmacies in Lusaka district, Zambia. Materials and Methods: This was a cross-sectional study that was conducted among 210 community pharmacies from September to November 2022 using a well-structured checklist in selected areas of Lusaka district. The availability was verified by a physical check of the product. The checklist contained the medicines listed both in the guidelines for diagnosis and treatment of malaria in Zambia as well as in the World Health Organization (WHO) malaria treatment guidelines. Results: This study found that all antimalarials listed in the local treatment guidelines for malaria were available in community pharmacies, though with the varying distribution. Of the 210 community pharmacies, 209 (99.5%) had artemether/lumefantrine in stock. The lowest available antimalarial was quinine/clindamycin, which was only available in 3 (1.4%) of the outlets. Conversely, 3 out of 16 (18.8%) antimalarials that were available in community pharmacies were not listed in the local treatment guidelines of malaria in Zambia, despite being listed in the WHO malaria treatment guidelines. This translated into a compliance level of 81.2% based on the local malaria treatment guidelines. Conclusion: This study concluded that antimalarials were available for all categories of malaria management in community pharmacies, though with a varying distribution. The presence of antimalarials not listed in the Zambian treatment guidelines is of public health concern which may have an impact on antimicrobial resistance in the future.
文摘This research article is based on a study of optimal frequency to the repairable system due to the failure finding interval to maximize as well as minimize the availability of some components devices. We studied together maintenance and corrective actions that carried out item of failure and periodic failure finding designed to check whether a system is still working. The model is proved as well as useful application in detecting the problem related to finding failure tasks of different scheme devices by maximization. The model formulated and the numerical application to the relevant mathematical model have been discussed to demonstrate the article quality. Therefore based on probability analytic development, the optimal maintenance policy is then obtained as solution of an optimization problem in which the maintenance cost rate is the objective function and the risk of corrective maintenance is the constraint function. Finally, the solution to the optimal device in the considered development model has been well adjusted due to derivation to the experimental observation rather than theory which will be taken into consideration in the next applied practical design research related and the system device provided that, the proactive device agreed with using the exponential distribution to the survive distribution function which can not be considered as valid.
文摘One of the ways of overcoming the cost of irrigation is through in-situ water harvesting at the plant roots. Super absorbent polymer (SAP) can facilitate water harvesting at the plant roots. This study attempted to assess the effect of SAP on plant available water (PAW) of different soils. In this study, SAP was sequentially added at the rate of 0.2%, 0.3% and 0.5% of the soil weight and its impact assessed in clay, sandy clay and sandy loam soils. The moisture retention characteristics of the original and SAP treated soils were studied using soil water retention curves (SWRC) and results modelled using Gardner model. PAW was estimated from SWRC as the difference between moisture content at 1.5 and 3 bar in all soils. The difference in PAW between original and treated soils was assessed at 5% level of significance. The WRC of all the samples was adequately found to be described by the Gardner model (Coefficient of determination R<sup>2</sup> ≥ 98% and residual standard error (RSE) ≤ 0.04). SWRC changed with increase in SAP percentage in clay, sandy clay and sandy loam soils. Clay had a higher change in water retention then sandy clay and lastly sandy loam. Plant available water content (PAW) in all soils increased. In clay soil it increased with increase in SAP from 0.3291 at zero SAP to 0.6223 at 0.5% SAP. Sandy clay soil increased in PAW from 0.2721 at zero SAP to 0.5335 at 0.5% SAP and Sandy loam soils from 0.1691 at zero SAP to 0.3461 at 0.5% SAP. Hence, from the study SAP can be used to conserve irrigation water in the plant roots and therefore reducing the cost since PAW has been increased.
文摘Unified identity authentication has become the basic information service provided by colleges and universities for teachers and students. Security, stability, high concurrency and easy maintenance are our requirements for a unified identity authentication system. Based on the practical work experience of China University of Geosciences (Beijing), this paper proposes a high availability scheme of unified identity authentication system based on CAS, which is composed of multiple CAS Servers, Nginx for load balancing, and Redis as a cache database. The scheme has been practiced in China University of Geosciences (Beijing), and the application effect is good, which has practical reference significance for other universities.
基金Project supported by the National Natural Science Foundation of Chi-na (No. 40432004, 40601086) the Natural Science Foundationof Zhejiang Province (No. Y504109).
文摘All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciation and availability. We studied the effects of heavy metal speciation and availability on soil microorganism activities along a Cu/Zn contamination gradient. Microbial biomass and enzyme activity of soil contaminated with both Cu and Zn were investigated. The results showed that microbial biomass was negatively affected by the elevated metal levels. The microbial biomass-C (Cmic)/organic C (Corg) ratio was closely correlated to heavy metal stress. There were negative correlations between soil microbial biomass, phosphatase activity and NH4NO3 extractable heavy metals. The soil microorganism activity could be predicted using empirical models with the availability of Cu and Zn. We observed that 72% of the variation in phosphatase activity could be explained by the NH4NO3-extractable and total heavy metal concentration. By considering different monitoring approaches and different viewpoints, this set of methods applied in this study seemed sensitive to site differences and contributed to a better understanding of the effects of heavy metals on the size and activity of microorganisms in soils. The data presented demonstrate the relationship between heavy metals availability and heavy metal toxicity to soil microorganism along a contamination gradient.
基金National Natural Science Foundation of China No.43071093
文摘The available soil water capacity (ASWC) is important for studying crop production, agro-ecological zoning, irrigation planning, and land cover changes. Laboratory determined data of ASWC are often not available for most of soil profiles and the nationwide ASWC largely remains lacking in relevant soil data in China. This work was to estimate ASWC based on physical and chemical properties and analyze the spatial distribution of ASWC in China. The pedo-transfer functions (PTFs), derived from 220 survey data of ASWC, and the empirical data of ASWC based on soil texture were applied to quantify the ASWC. GIS technology was used to develop a spatial file of ASWC in China and the spatial distribution of ASWC was also analyzed. The results showed the value of ASWC ranges from 15 × 10-2 cm3·cm-3 to 22 × 10-2 cm3·cm-3 for most soil types, and few soil types are lower than 15 × 10-2 cm3·cm-3 or higher than 22 × 10-2 cm3·cm-3. The ASWC is different according to the complex soil types and their distribution. It is higher in the east than that in the west, and the values reduce from south to north except the northeastern part of China. The "high" values of ASWC appear in southeast, northeastern mountain regions and Northeast China Plain. The relatively "high" values of ASWC appear in Sichuan basin, Huang-Huai-Hai plain and the east of Inner Mongolia. The relatively "low" values are distributed in the west and the Loess Plateau of China. The "very low" value regions are the northern Tibetan Plateau and the desertified areas in northern China. In some regions, the ASWC changes according to the complex topography and different types of soils. Though there remains precision limitation, the spatial data of ASWC derived from this study are improved on current data files of soil water retention properties for Chinese soils. This study presents basic data and analysis methods for estimation and evaluation of ASWC in China.
基金Project(51561135003)supported by the International Cooperation and Exchange of the National Natural Science Foundation of ChinaProject(51338003)supported by the Key Project of National Natural Science Foundation of China
文摘A new methodology for multi-step-ahead forecasting was proposed herein which combined the wavelet transform(WT), artificial neural network(ANN) and forecasting strategies based on the changing characteristics of available parking spaces(APS). First, several APS time series were decomposed and reconstituted by the wavelet transform. Then, using an artificial neural network, the following five strategies for multi-step-ahead time series forecasting were used to forecast the reconstructed time series: recursive strategy, direct strategy, multi-input multi-output(MIMO) strategy, DIRMO strategy(a combination of the direct and MIMO strategies), and newly proposed recursive multi-input multi-output(RECMO) strategy which is a combination of the recursive and MIMO strategies. Finally, integrating the predicted results with the reconstructed time series produced the final forecasted available parking spaces. Three findings appear to be consistently supported by the experimental results. First, applying the wavelet transform to multi-step ahead available parking spaces forecasting can effectively improve the forecasting accuracy. Second, the forecasting resulted from the DIRMO and RECMO strategies is more accurate than that of the other strategies. Finally, the RECMO strategy requires less model training time than the DIRMO strategy and consumes the least amount of training time among five forecasting strategies.
基金supported by the Key Knowledge Innovation Project of Chinese Academy of Sciences (KSCX2-YW-Z- 1020)the National Basic Research Program of China (2009CB825104)the National Natural Science Foundation of China (30970547)
文摘Eremosparton songoricum (Litv.) Vass is a dwarf clonal shrubby legume developed on the windward slopes of mobile or semi-fixed sand dunes of Central Asia. It is assumed that E. songoricum must possess a high degree of phenotypic plasticity for such a heterogeneous habitat. The variations of E. songoricum plants growing in two typical microhabitats (the upper slope and the lower slope of semi-mobile dune) were investigated. The morphological characteristics and the biomass allocation patterns were measured and compared at the clonal fragment level. Compared with the clonal fragment on the lower slope of dune, the clonal fragment on the upper slope of the dune (a) declined in total biomass and ramet height, (b) increased the length of rhizomes and the number of roots, (c) increased the degree of asym- metry, and (d) heightened allocation to the belowground biomass. Our results confirmed the hypothesis of high phenotypic adjustment capacity of E. songoricum to habitat moisture availability. Phenotypic plasticity of E. songoricum contributed to reduce the damage risk, led to an environmentally induced specialization in function of resources exploitation, resulted in its persistence in heterogeneous environments and was adaptive in sand dune environment.
基金The Grand Projects of Innovation Engineering Chinese Academy of Sciences(No. KZCX1 SW 12 2002 2006)
文摘Typical sediments from Taihu Lake, a meso-to-hypereutrophic lake, were collected and examined on the basis of P-fractionation by sequential extraction scheme. Sedimentary inorganic phosphorus were fractioned into four forms and the rank order according to the mean concentration of P-fractions in Taihu Lake was NaOH-P>BD-P>HCl-P>NH_4Cl-P. The concentrations of BD-P were linearly correlated with the content of active Fe(R2=0.96). Also, the linear relationship between the sum of BD-P and NaOH-P and the sum of active Fe and active Al content was observed within the six sediments investigated(R2=0.96). Moreover, the bio-available phosphorus(BAP) content was estimated by the sum of NH_4Cl-P, BD-P, and NaOH-P, viz. BAP=NH_4Cl-P+NaOH-P+BD-P. In Taihu Lake, the BAP contents are ranging from 0.10 mg/g dw to 1.25 mg/g dw, and average 0.40 mg/g dw for all sediment samples. The relative contributions of BAP to total sedimentary phosphorus(TP) and inorganic sedimentary phosphorus(IP) range from 18.67% to 50.79%(33.61% on average) and from 52.82% to 82.09%(67.81% on average), respectively.
基金This work was supported by a grant from Fund of Doctorial Programmes of State Educational Commission of China
文摘The availability of three dissolved organic phosphorus (DOP) compounds as nutrient sources for experimentalcultare of three algae was studied. Results indicated that these compounds could be utilized byalgae, and that dissolved inorganic phosphorus (DIP) was first to be uptaken when various forms ofphosphorus (DIP and DOP) co-existed. Dicrateria zhanjiangensis’ uptake of sodium glycerophosphatewas faster than that of D-ribose-5-phosphate. The increase of sodium glycerphosphate had little effecton the maximum uptake rate(V<sub>max</sub>) of Chlorella sp., but increased the semisaturation constant(K<sub>s</sub>) remarkably;the photosynthesis rates(PR) of Dicrateria zhanjiangensis and Chlorella sp. were rarely affected byusing various forms of phosphorus in the culture experiments. The possible DOP pathways utilizedby algae are discussed.
基金supported by the National Key Research and Development Program of China (2016YFD03001093)the National Natural Science Foundation of China (31671626, 31771728)
文摘Soil with low phosphorus (P) availability and organic matter contents exists in large area of southwest of China, but some soybean genotypes still show well adaptations to this low yield farmland. However, to date, the underlying mechanisms of how soybean regulates soil P availability still remains unclear, like microbe-induced changes. The objective of the present study was to compare the differences of rhizosphere bacterial community composition between E311 and E109 in P-sufficiency (10.2 mg kg^-1) and P-insufficiency (5.5 mg kg^-1), respectively, which then feedback to soil P availability. In P-sufficiency, significant differences of the bacterial community composition were observed, with fast-growth bacterial phylum Proteobacteria, genus Dechloromonas, Pseudomonas, Massilia, and Propionibacterium that showed greater relative abundances in E311 compared to E109, while in P-insufficiency were not. A similar result was obtained that E311 and E109 were clustered together in P-insufficiency rather than in P-sufficiency by using principal component analysis and hierarchical clustering analysis. The quadratic relationships between bacterial diversity and soil P availability in rhizosphere were analyzed, confirming that bacterial diversity enhanced the soil P availability. Moreover, the high abundance of Pseudomonas and Massilia in the rhizosphere of E311 might increased the P availability. In the present study, the soybean E311 showed capability of shaping rhizosphere bacterial diversity, and subsequently, increasing soil P availability. This study provided a strategy for rhizosphere management through soybean genotype selection and breeding to increase P use efficiency, or upgrade middle or low yield farmland.
基金This research was jointly supported by the Special Fund for Agro-scientific Research in the Public Interest(201503137)Program of Creation and Utilization of Germplasm of Mushroom Crop of“111”Project(D17014)+1 种基金National-level International Joint Research Centre(2017B01011)and the Changchun Science and Technology Project(15SS11).
文摘Background:Flammulina velutipes stem waste(FVS)is the by-product of mushroom industry.The objectives of this study were to determine the available energy and amino acid digestibility of FVS fed to pigs,and to evaluate the effects of dietary FVS inclusion on growth performance,biochemical profile of serum,fecal short chain fatty acid(SCFA)concentration,carcass traits,meat quality,intestinal morphology and microflora of pigs.In Exp.1,twelve crossbred barrows with initial body weight(IBW)of 37.48±4.31 kg were randomly allotted to 2 dietary treatments,including a corn basal diet and an experimental diet containing 24.35%FVS.In Exp.2,twelve barrows fitted with an ileal T-cannula(IBW:32.56±1.67 kg)were randomly allotted to 2 dietary treatments,which included a N-free diet and an experimental diet containing 40.0%FVS.In Exp.3,ninety growing pigs(IBW:63.98±6.89 kg)were allotted to 1 of 3 treatment diets for 63 d,including a basal diet and 2 experimental diets with 2.5%and 5%FVS,respectively.Results:The digestible energy(DE)and metabolizable energy(ME)of FVS were 4.58 and 4.06 MJ/kg on dry matter basis,respectively,and the standardized ileal digestibility(SID)of indispensable AAs ranged from 17.50%to 59.47%.Pigs fed diets with 2.5%FVS showed no difference on average daily gain(ADG)and gain to feed ratio(G/F).Although dietary 5%FVS inclusion impaired apparent total tract digestibility(ATTD)of organic matter and gross energy,it elevated the SCFA concentration(P≤0.04)in gut and antioxidant capacity in serum.In addition,dietary FVS inclusion depressed the backfat thickness(P=0.03)in pigs.The longissimus dorsi muscle of pigs fed FVS revealed higher n-3 polyunsaturated fatty acid concentration and optimized fatty acid composition.Dietary 2.5%FVS inclusion also improved the intestinal development and health by increasing the villius height to crypt depth ratio(V/C)in jejunum(P<0.01),and promoting microbial diversity and beneficial microbiota proliferation.Conclusions:It is feasible to include moderate content of FVS as an unconventional fiber ingredient in diet of growingfinishing pigs.
基金supported by the National Natural Science Foundation of China(7120116671201170)
文摘This paper considers a project scheduling problem with the objective of minimizing resource availability costs appealed to finish al activities before the deadline. There are finish-start type precedence relations among the activities which require some kinds of renewable resources. We predigest the process of sol-ving the resource availability cost problem (RACP) by using start time of each activity to code the schedule. Then, a novel heuris-tic algorithm is proposed to make the process of looking for the best solution efficiently. And then pseudo particle swarm optimiza-tion (PPSO) combined with PSO and path relinking procedure is presented to solve the RACP. Final y, comparative computational experiments are designed and the computational results show that the proposed method is very effective to solve RACP.
基金Sponsored bythe National Natural Science Foundation of China(70671009)the Postgraduate Science and Innovation Project of Beijing Instituteof Technology (GC200818)
文摘The new model for parallel repairable system is introduced, and it is based on the practice problems of maintenance and the idea of Ion-Channel modeling. In the new model, repair times that are sufficiently short (less than some critical value) do not result in system failure, and such a repair interval is omitted from the downtime record. Usually, the underlying process is Markov process if the durations of working and repair time have the negative-exponential distributions, but the new system has not the Markov properties, which is worth to study. The reliability indexes such as instantaneous availability and steady-state availabilities for the new system are given through probability analysis. A numerical example is given to illustrate the results.
基金founded by the Knowledge Innovation Program of Chinese Academy of Sciences (KZCX2-EW-302)the National Natural Science Foundation of China (41073061, 41330528, 41203054)
文摘Short-term nitrous oxide(N2O) pulse emissions caused by precipitation account for a considerable portion of the annual N2O emissions and are greatly influenced by soil nitrogen(N) dynamics. However, in Chinese semiarid temperate steppes, the response of N2O emissions to the coupling changes of precipitation and soil N availability is not yet fully understood. In this study, we conducted two 7-day field experiments in a semiarid temperate typical steppe of Inner Mongolia, China, to investigate the N2O emission pulses resulting from artificial precipitation events(approximately equivalent to 10.0 mm rainfall) under four N addition levels(0, 5, 10 and 20 g N/(m2·a)) using the static opaque chamber technique. The results show that the simulated rainfall during the dry period in 2010 caused greater short-term emission bursts than that during the relatively rainy observation period in 2011(P〈0.05). No significant increase was observed for either the N2O peak effluxes or the weekly cumulative emissions(P〉0.05) with single water addition. The peak values of N2O efflux increased with the increasing N input. Only the treatments with water and medium(WN10) or high N addition(WN20) significantly increased the cumulative N2O emissions(P〈0.01) in both experimental periods. Under drought condition, the variations in soil N2O effluxes were positively correlated with the soil NH4-N concentrations in the three N input treatments(WN5, WN10, and WN20). Besides, the soil moisture and temperature also greatly influenced the N2O pulse emissions, particularly the N2O pulse under the relatively rainy soil condition or in the treatments without N addition(ZN and ZWN). The responses of the plant metabolism to the varying precipitation distribution and the length of drought period prior to rainfall could greatly affect the soil N dynamics and N2O emission pulses in semiarid grasslands.