Establishment of an indirect immunofluorescence assay for the detection of African swine fever virus antibodies

African swine fever(ASF)continues to cause enormous economic loss to the global pig industry.Since there is no safe and effective vaccine,accurate and timely diagnosis of ASF is essential to implement control measures.Indirect immunofluorescence assay(IFA)is a gold standard serological method recommended by the World Organization for Animal Health(WOAH).In this study,we used primary fetal kidney cells to establish a wild boar cell line(BK2258)that supported the efficient replication of ASF virus(ASFV)SD/DY-I/21 and showed visible cytopathic effect(CPE).Moreover,using BK2258,we established a sensitive and specific IFA for ASFV antibody detection.To standardize and evaluate the performance of this assay,we used serum samples from pigs infected with the low virulent genotype I SD/DY-I/21 and genotype II HLJ/HRB1/20,and immunized with the vaccine candidate HLJ/18-7GD,field samples,and negative serum samples.The IFA reacted with the ASFV-positive sera and displayed bright fluorescence foci.There was no non-specific green fluorescence due to cellular senescence or other cell damage-causing factors.Compared to a commercial indirect enzyme-linked immunosorbent assay(iELISA),ASFV antibodies were detected 1–4 days earlier using our IFA.The detection limits of the IFA and iELISA for the same ASFV-antibody positive serum samples were 1:25,600 and 1:6,400,respectively,indicating that the IFA is more sensitive than iELISA.The newly established IFA was highly specific and did not cross-react with sera positive for six other important porcine pathogens(i.e.,Classical swine fever virus(CSFV),Porcine reproductive and respiratory syndrome virus(PRRSV),Porcme circovirus type 2(PCV2),Pseudorabies virus(PRV),Foot-and-Mouth disease virus type O(FMDV/O),and Porcine epidemic diarrhea virus(PEDV)).This study thus provides a sensitive,specific,and reliable detection method that is suitable for the serological diagnosis of ASF.

基于FLUS-UGB模型的城镇扩展模拟研究

优化城镇空间布局结构、提高城镇化质量是新型城镇化发展的必然要求。以南京市为研究区,结合地形地貌、交通、人口等多源数据提取影响因子,依据2015、2019年的土地利用数据利用FLUS-UGB模型模拟南京市2035年城镇空间布局。根据模拟结果,南京市城镇空间扩展呈现一核多点的特征,并依附现有城镇建设地块或向外扩延或向内集聚增长,城镇空间的拓展主要沿长江两岸展开。此项研究可为因地制宜优化区域城镇空间布局、合理划定城镇开发边界,提供参考依据。

基于FLUS和InVEST模型的云贵高原土地利用与生态系统服务时空变化多情景模拟研究

[目的]探讨云贵高原不同情景下的土地利用与生态系统服务时空变化,为云贵高原土地利用空间格局优化、生态系统服务功能提升和可持续发展策略制定提供科学依据。[方法]以云贵高原为研究对象,以2001年、2010年和2020年3期MCD12Q1土地覆被数据为基础数据,辅以自然和社会经济数据,基于ArcGIS,FLUS模型和InVEST模型,模拟2030年、2040年和2050年自然发展情景、生态保护情景和耕地保护情景下的土地利用以及碳储量、产水量和土壤保持量3项生态系统服务功能时空分布格局。[结果](1)不同情景下云贵高原的土地利用变化以林地持续增加和草地持续减少为主要趋势;耕地保护情景下,耕地面积最高可占总面积的10.38%;生态保护情景下,林草面积在2050年可达总面积的90%。(2) 3种情景下,云贵高原2020—2050年碳储量和土壤保持量均呈上升趋势,而产水量呈下降趋势。生态保护情景下,2050年碳储量预测值最高,为8.13×10^(9) t;产水量减少速率显著低于另外两种情景,降幅为0.46%。(3)宜昌市、普洱市和常德市等市州的生态系统服务供给能力较高;而贵阳市、毕节市和安顺市等市州的生态系统服务供给能力较低。[结论]云贵高原2020—2050年整体生态系统服务供给能力较好,各项服务功能在不同情景下表现出较强的空间聚集性和异质性。云贵高原今后的生态系统服务管理和可持续发展中,应考虑不同生态系统服务功能的空间异质性以及林地面积持续增加可能带来的水资源失衡问题。

基于Invest模型和Flus模型的江苏省碳储量变化模拟与预测

为明确土地利用变化对碳储量的具体影响,实现耕地、林地等生态环境的更好保护,以江苏省为例,基于2000年、2010年和2020年土地利用数据,采用Invest模型的碳储存和固定模块以及Flus模型ANN模块、CA模块、Markov Chain模块,分析了江苏省不同土地利用类型碳储量变化特征,并预测了自然发展情景和生态保护情景下2030年和2050年江苏省碳储存与固定情况。结果表明,2000年、2010年与2020年,江苏省碳储量整体呈下降趋势,从1803.948×10^(6)t下降至1641.008×10^(6)t,其中耕地碳储量下降最多,为239.494×10^(6)t。这种现象的发生与江苏省工业化和城市化导致的耕地和林地等面积的减少并转为建筑用地有关。此外,各市碳储量差异较显著,其中盐城市碳储量最大,占全省总碳储量的16.12%,无锡市在全省碳储量中占比最小(4.12%)。基于ArcGIS 10.2软件和GeoDa 1.20软件分析发现,2000—2010年,南京、无锡、常州的碳储量分布呈低-低聚集,连云港市呈低-高聚集;2020年无锡、常州、镇江呈现低-低聚集,连云港市呈现高-高聚集。本研究预测结果表明2030年和2050年的生态保护情景下碳存储能力较自然发展情景有一定提升,分别提升6.069×10^(6)t和5.861×10^(6)t。本研究结果可为江苏省更好地建设生态环境提供数据支撑。

基于FLUS模型多情景土地利用变化对陆地生态系统碳储量影响——以江西萍乡为例

[目的]揭示萍乡碳储量时空分布特征,阐明土地地类变化与碳储量之间的关系,为探明区域生态系统碳储量状况提供数据支撑。[方法]利用FLUS(future land use simulation)模型与InVEST(integrated valuation of ecosystem services and trade-offs)模型,预测了2030年萍乡市3种不同情景下(自然发展、耕地保护和生态优先)碳储量值。[结果](1)2010—2020年萍乡市碳储量整体呈下降趋势,共减少1.47×10^(6)t;(2)耕地、建设用地、草地、水体和建设用地面积增加和林地与灌木面积减少,是导致碳储量变化的主要原因;(3)2030年自然发展、耕地保护和生态优先情景下陆地生态系统碳储量分别约为4.906×10^(7),4.919×10^(7),5.038×10^(7)t,其中生态优先情景下碳储量损失最少。[结论]萍乡生态系统碳储量呈下降趋势,主要受耕地与建设用地增大的影响,未来应加强对安源区与经济开发区重点变化区域的监测研究。

基于GeoSOS-FLUS模型的乌鲁木齐生态空间模拟

基于GeoSOS-FLUS模型,利用2005和2020年的土地利用数据,对乌鲁木齐市土地利用变化及其农业生态效应进行分析,并建立农田保护、生态保护和城市发展3种情景模拟。结果表明,GeoSOS-FLUS模型具有较高的模拟精度和适用性,能够反映乌鲁木齐市土地利用变化特征。在不同情景模拟下,乌鲁木齐市土地利用空间布局呈现出不同的变化趋势和农业生态效应。

Effect of β-Glucan (Angel Yeast) Compared to a Placebo on Cold and Flu Incidence and Symptoms in an Adult Population—A Double Blind, Randomised Controlled Trial

Background: 1-3, 1-6 β-glucan derived from Baker’s yeast (Saccharomyces cerevisiae) has been widely studied for its immune stimulatory capabilities and safety. Previous studies found β-glucan to have efficacy at reducing incidence of URTIs as well as being a low risk for negative side effects. The current study aimed to examine the effects of yeast β-glucan (Angel Yeast) on cold and flu incidences and symptoms in healthy adults. Methods: Two hundred and thirty-one males and females aged 18 to 65 years old supplemented with either β-glucan or a placebo for 3-months. Participants completed a general health questionnaire every 4 weeks and in addition, if participants experienced any cold or flu symptoms, these were recorded daily (along with severity) until resolved or up to 2 weeks. Results: Supplementation with β-glucan reduced the self-reported severity of sore throats and improved sleep quality compared to the placebo group. Conclusions: Yeast β-glucan supplementation appears to be able to help reduce certain symptoms experienced during a cold or flu episode and is safe and well tolerated.

Accurate models and nutritional strategies for specific oxidative stress factors: Does the dose matter in swine production?

Oxidative stress has been associated with a number of physiological problems in swine,including reduced production efficiency.Recently,although there has been increased research into regulatory mechanisms and antioxidant strategies in relation to oxidative stress-induced pig production,it remains so far largely unsuccessful to develop accurate models and nutritional strategies for specific oxidative stress factors.Here,we discuss the dose and dose intensity of the causes of oxidative stress involving physiological,environmental and dietary factors,recent research models and the antioxidant strategies to provide theoretical guidance for future oxidative stress research in swine.

基于FLUS-Markov模型的玉溪市生态系统服务价值时空演变与预测

基于玉溪市2010年、2020年2期生态景观类型数据和粮食产量经济价值修正生态系统服务价值系数,分析玉溪市生态景观类型及生态系统服务价值分布特征,采用FLUS-Markov模型预测玉溪市2030年生态系统服务价值及其分布。结果表明,该模型预测结果的Kappa系数提高至0.8969,整体精度为0.9393,精度较高;2010—2020年玉溪市林地、草地的面积呈减少趋势,以林地、草地、水域为主的生态系统仍然面临威胁;2030年玉溪市生态系统服务价值为535.0471亿元,变化率为-0.1297%,玉溪市应加强对林地、草地的保护,加强退耕还林、退耕还草政策的实施,合理控制草地、林地向耕地的转化;2030年玉溪市生态系统服务价值依然表现为西部>中部>东部;2030年玉溪市各县市区生态系统服务价值贡献率由高到低依次为新平县、元江县、峨山县、易门县、华宁县、红塔区、江川区、澄江市、通海县。

Delineation of urban growth boundary based on FLUS model under the perspective of land use evaluation in hilly mountainous areas

With rapid economic development,the size of urban land in China is expanding dramatically.The Urban Growth Boundary(UGB)is an expandable spatial boundary for urban construction in a certain period in order to control the urban sprawl.Reasonable delineation of UGB can inhibit the disorderly spread of urban space and guide the normal development of the city.It is of practical significance for the construction of green urban space.The study utilizes GIS technology to establish a land construction suitability evaluation system for Nankang city,which is experiencing rapid urban expansion,and outlines the preliminary UGB under the future land use simulation(FLUS)model.At the same time,considering the coupled coordination of"Production-Living-Ecological Space",and based on the suitability evaluation,we revised the preliminary UGB by combining the advantages of the patch-generating land use simulation(PLUS)model and the convex hull model to delineate the final UGB.The results show that:1)the comprehensive score of the evaluation of the suitability of the construction of land from high to low shows the distribution of the center of the city to the surrounding circle type spread,the center of the city has the highest suitability score.The results of convex hull model show that the urban expansion type of Nankang is epitaxial.In the future,the urban expansion will mainly occur in the northern part of the city.The PLUS model predicts an increase of 3359.97 hm^(2)of construction land in Nankang by 2035,of which 2022.97 hm^(2)is urban construction land.2)The FLUS model has a prediction accuracy of 86.3%and delineates a preliminary UGB area of 9215.07 hm^(2).3)We used the results of the construction suitability evaluation,PLUS model simulation results,and convex hull model predictions to revise the originally delineated UGB.The final delineated UGB area is 8895.67 hm^(2)and it is capable of meeting the future development of the study area.The results of the delineation can promote sustainable urban development,and the delineation methodology can provide a reference basis for the preparation of territorial spatial planning.

基于GeoSOS-FLUS模型的荆州市生态安全评估

为探索荆州市的生态安全底线,模拟未来的土地利用变化和生态系统服务价值变化,为荆州市的生态保护制定合理的政策建议,从供给和需求的角度,结合粮食安全标准,测算了荆州市的生态安全底线;利用GeoSOS-FLUS模型在自然发展、生态保护、耕地保护和双重保护4种情景下,模拟了未来的土地利用变化和生态系统服务价值的变化。结果表明:荆州市的供给生态安全底线为1 227.56亿,需求生态安全底线为7 690.12亿,存在较大的生态安全缺口;双重保护情景下的生态系统服务价值最接近需求生态安全底线,也能提供相对更多的粮食,最有利于平衡生态安全和粮食安全。本文探索性地从供给和需求的角度结合粮食安全标准,计算了荆州市的生态安全底线,利用了一种先进的土地利用变化模拟方法,为其他地区的生态安全评估和保护提供了借鉴,为荆州市的生态环境优化模式和方向提供了参考。

基于FLUS乌鲁木齐城镇-农业-生态空间特征分析及发展对策

做好城镇-农业-生态3类空间规划,是未来城市规划以及可持续发展的重要保障,为此做好空间特征分析对城市建设具有重要的指导意义。本研究结合2005、2008、2012、2016和2018年5期遥感影像数据提取土地利用数据,运用GIS技术研究乌鲁木齐市3类空间变化的规律,通过数据发现2005—2018年乌鲁木齐农业空间和生态空间面积减少,城镇空间面积增加;结合自然因子、社会经济因子和可达性因子,运用GeoSOS-FLUS模型,设定城镇空间发展、农业空间发展和生态空间发展情景进行分析,结果发现3类空间面积变化较为显著,同时城镇空间的发展与生态空间面积存在一定负向关系,因此在未来城镇建设时,要重视农业-生态空间保护工作,坚守城镇开发边界控制线,协调好发展与环境的关系。

基于改进FLUS模型的北京市低碳土地利用情景模拟

合理的土地利用计划对避免高碳排放有着重要意义,进行低碳经济视角下的土地利用优化模拟有利于绿色发展和土地资源科学配置。以北京市为例,将兴趣点(point of interest,POI)数据纳入FLUS模型的BP-ANN算法模块中对其进行改进,利用2010年和2020年2期土地利用数据对改进模型的模拟精度进行对比验证。在此基础上,耦合Markov法及理想点法,对研究区2030年自然演变情景及低碳经济情景下的土地数量结构和空间布局进行模拟分析。研究结果表明:①引入POI数据的FLUS模型在模拟2020年土地利用时,Kappa系数提高4.85%、总体精度提高3.42%,改进模型有利于提高模拟精度;②经模拟验证,在自然演变情景中,碳排放量增加7.70%,建设用地面积增长7.68%,耕地、草地面积持续减退;③在低碳经济情景中,与自然演变情景相比,碳排放量减少198.49万t,建设用地持续扩张的趋势得到遏制,浅山区草地被占用的现象得到缓解,北部林地面积增长明显。研究说明了土地利用模型的模拟精度随城市发展元素的变化而变化,纳入POI数据可以为土地规划提供更好的决策支持,低碳经济导向的土地结构调整及空间布局优化,可以为区域土地合理利用和规划布局提供参考。

基于InVEST与FLUS模型的准格尔旗水源涵养功能分析

土地利用是生态系统水源涵养功能的一个重要驱动力。随着全球气候变化的发展,准格尔旗水源短缺问题日益严重。本研究基于FLUS模型预测自然发展、城市发展与生态保护情景下2040年准格尔旗土地利用变化,运用InVEST模型分析了准格尔旗水源涵养的时空变化,结果表明:三种情景下FLUS模型的Kappa系数为0.87,0.88和0.83,均大于0.80,说明FLUS模式能很好地模拟研究区的土地演替。运用InVEST模型得出2040年城市发展情景水源涵养量最低为2.98×10^(8)m^(3),生态保护情景水源涵养量最多为3.37×10^(8)m^(3)。全旗的水源涵养量总体表现为“东高西低”“北高南低”的基本分布模式。根据各土地利用类型单位面积水源涵养能力的差异,其强度按以下顺序排列:草地>林地>耕地>水域>建设用地>未利用土地。通过对准格尔旗的土地利用状况和水源涵养功能的研究,能够为规划生态保护区提供管理建议,为社会经济发展提供理论支撑。

不变与变:从“SARS”到“Swine Influenza”的中文译名谈起

SARS与Swine Influenza为发生在本世纪初的两场重大传染疾病,其中SARS的中文译名一直未变,译为"非典";Swine Influenza则从开始的"猪流感"更名为"甲型H1N1流感"。本文尝试从翻译与传播的视角探讨这两种疾病中文译名的不变与变,分析背后的原因,并提出SARS中文译名的改进译法。

FLUS与灰色预测模型支持下的乌鲁木齐地区碳排放时空演变与预测

自从“双碳”目标提出以来,进行土地利用碳排放时空变化特征研究对碳减排政策的制定具有指导意义。以乌鲁木齐地区为对象,基于FLUS与灰色预测模型预测2030年土地利用碳排放量,并与往年相结合模拟研究区2000—2030年碳排放量的时空格局变化。结果表明:(1)研究区2000—2020土地利用变化中林地、未利用地、水域、建设用地为正增长,耕地与草地为负增长,草地与耕地面积主要是向未利用地与建设用地转出,水域与林地面积变化相对比较稳定。(2)2000—2020年碳排放总量呈增加的趋势,建设用地是主要的决定因素,研究区碳排放量呈“由南向北递增”的空间分布特点,米东区最高,达坂城区最低。(3)2030年不同情景碳排放量计算结果中,耕地保护情景碳排放总量最高,为2773.67万t,生态环境情景碳排放量最低,为2767.15万t。(4)研究区从2000—2030年大部分地区趋于稳定,变化的区域呈大聚集与零星分布的特点,碳排放呈增加的区域主要分布于研究区中心区与北部的米东区,呈减少的区域主要分布于南部的乌鲁木齐县与达坂城区。碳排放增加的区域在耕地保护情景达到最大,占研究区面积的25.4%,碳排放减少的区域在生态环境达到最大,占研究区面积的13.3%。

Recovery of Nitrogen and Phosphorous as Struvite From Swine Waste Biogas Digester Effluent

Objective To investigate the feasibility of nitrogen and phosphorus recovery from swine waste biogas digester effluent and the effects of pH and NH4^＋： Mg2^＋： PO4^3- molar ratio on its precipitation. Methods Precipitation experiments with swine waste biogas digester effluent were conducted at pH 7.5, 8.0, 8.5, and 9.0 together with NH4^＋： Mg^2＋： PO4^3- molar ratios 1： 0.2： 0.08, 1： 1： 1, and 1： 1.5： 1.5. Chemical and X-ray diffraction （XRD） analysis were done to determine the composition of the precipitate. Results The highest removal and recovery of NH4^＋ and PO4^3- were achieved at pH 9.0 in each experiment. The elevation of pH to 9.0 alone could decrease the initial PO4^3- concentration from 42 mg L^-1 to 4.7 mg L-1 and 89.2% PO4^3- recovery was achieved. The pH-molar ratio combination 9.0-1： 1.5： 1.5 effected 76.5% NH4^＋ and 68.5% PO4^3- recovery. The molar ratio of 1： 1： 1 together with pH elevation to 9.0 was determined to be the optimum combination for both NH4＋ and PO4^3- removal as it recovered over 70% and 97% of the initial NH4^＋ and PO4^3-, respectively. Conclusions Nitrogen and phosphorus can be recovered from biogas digester effluent as struvite.

Enhancing treatment efficiency of swine wastewater by effluent recirculation in vertical-flow constructed wetland

Livestock wastewater has been a major contributor to Chinese cultural eutrophication of surface waters. Constructed wetlands are under study as a best management practice to treat wastewater from dairy and swine operations, but the removal efficiency of pollutants is relatively low. Enhancing the treatment efficiency of livestock wastewater by effluent recirculation was investigated in a pilot-scale vertical-flow constructed wetland. The wetland system was composed of downflow and upflow stages, on which narrow-leaf Phragmites communis and common reed Phragraites Typhia are planted, respectively; each stage has a dimension of 4 m^2 （2 m × 2 m）. Wastewater from facultative pond was fed into the system intermittently at a flow rate of 0.4 m^3/d. Recirculation rates of 0, 25%, 50%, 100% and 150% were adopted to evaluate the effect of the recirculation rate on pollutants removal. It shows that with effluent recirculation the average removal efficiencies of NH4-N, biological oxygen demand （BOD5） and suspended solids（SS） obviously increase to 61.7%, 81.3%, and 77.1%, respectively, in comparison with the values of 35.6%, 50.2%, and 49.3% without effluent recirculation. But the improvement of TP removal is slight, only from 42.3% to 48.9%. The variations of NH4-N, dissolved oxygen（DO） and oxidation-reduction potential（ORP） of inflow and outflow reveal that the adoption of effluent recirculation is benefi- cial to the formation of oxide environment in wetland. The exponential relationships with excellent correlation coefficients （R2 〉0.93） are found between the removal rates of NH4-N and BOD5 and the recirculation rates. With recirculation the pH value of the outflow decreases as the alkalinity is consumed by gradually enhanced nitrification process. When recirculation rate is kept constant 100%, the ambient temperature appears to affect NH4-N removal, but does not have significant influence on BOD5 removal.

Struvite Recovery from Swine Waste Biogas Digester Effluent through a Stainless Steel Device under Constant pH Conditions

Objective To investigate the struvite precipitation under constant and non-constant pH conditions and to test a stainless steel device under different operating regimes to maximize the recovery of struvite. Methods The molar ratio of NH4^＋： Mg^2＋ PO43 was adjusted to 1： 1.2：1.2 and pH was elevated to 9.0. The absorbance measurement was used to trace the process of struvite crystallization. Wastewater and precipitate analysis was done by standard analytical methods. Results The pH constant experiment reported a significantly higher struvite precipitation （24.6±0.86 g） than the non-constant pH experiment （19.8±1.86 g）. The SAR ranged from 5.6 to 8.2 g m^-2h^-1 to 3.6-4.8 g m^-2h^-1 in pH constant and non-constant experiments, respectively. The highest struvite deposit on the device was found in regime 3 followed by in regimes 2 and 4. The highest PO4^3- （97.2%） and NH4^＋ （71%） removal was reported in the R1 regime. None of the influent Cu^2＋ or Zn^2＋ was precipitated on the device. Conclusion A higher struvite yield is evident in pH constant experiments. Moreover, the stainless steel device facilitates the isolation of heavy metal free pure （around 96%） struvite from swine waste biogas digester effluent contaminated with Cu^2＋ and Zn^2＋ and the highest yield is attainable with the device operating at 50 rpm with agitation by a magnetic stirrer.

Use of a Multiplex RT-PCR Assay for Simultaneous Detection of the North American Genotype Porcine Reproductive and Respiratory Syndrome Virus,Swine Influenza Virus and Japanese Encephalitis Virus

A multiplex reverse transcriptase-polymerase chain reaction(multiplex RT-PCR) assay was developed and subsequently evaluated for its efficacy in the detection of multiple viral infections simultaneously,in swine.Specific primers for each of the 3 RNA viruses,North American genotype porcine reproductive and respiratory syndrome virus,Japanese encephalitis virus,and swine influenza virus,were used in the testing procedure.The assay was shown to be highly sensitive because it could detect as little as 10-5 ng of each of the respective amplicons in a single sample containing a composite of all 3 viruses.The assay was also effective in detecting one or more of the same viruses in various combinations in specimens,including lymph nodes,lungs,spleens,and tonsils,collected from clinically ill pigs and in spleen specimens collected from aborted pig fetuses.The results from the multiplex RT-PCR were confirmed by virus isolation.The relative efficiency(compared to the efficiency of separate assays for each virus) and apparent sensitivity of the multiplex RT-PCR method show that this method has potential for application in routine molecular diagnostic procedures.