China's miraculous development has faced major challenges in recent years, partly triggered by the U.S.-China trade war that started in 2018. This paper provides a systematic evaluation of the detrimental consequences of the trade war over the period from 2018:Q1 to 2021:Q1 for China's final demands and industrial outputs as well as for Chinese consumers' and importers' welfare. We construct a Leontief input-output framework with isoelastic demands and complete tariff pass-through, and adopt Harberger's triangle approach to deadweight loss based on partial leakage of tariff revenues. We find that ICT, Furniture, Food, Primary, and Electrical were the most negatively affected sectors in terms of final demand changes, and that the negative impacts on sectoral outputs were largest in ICT and Auto. Our results indicate that Primary, Food, Paper, Petroleum, Chemicals, and ICT incurred the biggest deadweight losses over the entire tariff change, and that Primary, Food, Chemicals, ICT, and Machinery suffer large total losses with 20% tariff leakages. Primary was hurt the most in both measures. China's aggregate total loss amounted to US$1.57 billion, approximately 0.0089% of China's gross output. While the trade war led to a lose-lose outcome, China's aggregate total loss as a percentage of gross output is less than one-fifth of the counterpart in the U.S. Our main findings suggest that it would be Pareto improving to restore the order of globalization by mitigating trade barriers or confrontations.

We study misallocation and sectoral productivity in a heterogeneous firms model with generalized production. Different from neo-classical models of production, our model endogenizes production-techniques and introduces firm-specific technique-distortions alongside factor- and scale-dependent distortions. Applying this micro-founded framework to firm-level data (US, China and India), we quantify that, for a broad range of manufacturing industry clusters, technique distortions generate more severe misallocation and sectoral TFP losses than capital and output distortions, accounting for about three quarters of the detrimental productivity effects. We thus uncover a quantitatively important channel for productivity growth and economic development resulting from within-firm organization of production.

We extend the recent macro housing literature by including endogenous internal urban structure to better fit with important stylized facts. We construct a two-sector optimal growth model of housing where consumable housing is produced by land and housing structures, where within-city locational choice is explicitly modeled. Housing services derive positive utility but are decayed away from the city center. Our model enables a full characterization of the dynamic paths of housing and housing and land prices. The model is calibrated to fit part of the stylized facts: faster growth of housing structures than housing, faster growth of land prices than housing prices, and downward housing price and land rent gradients within a city. The calibrated model can then be used to predict the remaining untargeted part of stylized facts: a locationally steeper land rent gradient than the housing price gradient, relatively flatter housing quantity and price gradients in larger cities with flatter population gradients and moderate rise in the housing expenditure share. The calibrated model can further yield additional insights on housing dynamics and spatial distribution. The main punchline is: nonhomotheticities in housing preference and housing production are crucial for realistic model predictions particularly to account for internal urban features.

We construct a dynamic general equilibrium model of foreign direct investment (FDI) and foreign technology adoption, incorporating adoption barriers, international technology spillover, and relative price advantages.A higher FDI conversion efficacy, a lower adoption barrier, or a stronger international technology spillover, together with a lower relative price of FDI, can propel an economy to exhibit a flying geese paradigm escaping from a middle-income trap and catching up with the world frontier.We calibrate the model to eight representative Asian economies, including Asian Tigers and less-developed countries.Growth accounting exercises show that total factor productivity, FDI conversion efficacy, and foreign technology spillover drive Asian Tigers' growth miracle, whereas a reduced adoption barrier and a favorable relative price of FDI are more crucial for the growth of less-developed Asian economies.The counterfactual analysis confirms that technology-embodied FDI serves as a flying propeller, explaining almost two-thirds of their economic growth.

Sugarcane is a major crop for sugar production around the world. The complexity of the sugarcane genome creates challenges for the use of both conventional and molecular breeding methods to improve sugarcane at a genetic level. DNA sequencing is an important tool to assess how the genus Saccharum and the genera of the Saccharum complex are interrelated. Here, we identify the kinship of Nepal2013-6 (Saccharum spontaneum, x = 10) using a tetra-primer amplification refractory mutation system (ARMS) PCR. Based on rDNA-ITS sequence analysis, the accession Nepal2013-6 falls within a single cluster with S. spontaneum (Yunnan82-114 and SES208), which is consistent with the previous results. Moreover, fluorescence in situ hybridization (FISH) results indicate that the 5S rDNA spots are consistent with the chromosomal ploidy in the analytical Saccharum materials, whereas 35S rDNA has similar or fewer sites than the ploidy. Therefore, 5S rDNA FISH patterns would be more suitable than 35S rDNA for chromosomal ploidy analysis in S. spontaneum with varied basic chromosome number x = 8, 9, 10. Altogether, these results indicate that the rDNA sequences will be a useful marker for further rapidly identifying the relationship and ploidy of S. spontaneum in sugarcane breeding.

We construct a dynamic general equilibrium model of housing, incorporating some key features that bridge time and space. We model explicitly the evolution of housing structures/household durables and the separate role played by land, fully accounting for households’ locational choice decisions. Housing services derive positive utility, but are decayed away from the city center. Our model enables a full characterization of the dynamic paths of housing as well as housing and land prices. The model is particularly designed to be calibrated to fit some important stylized facts, including faster growth of housing structure/household durables than housing, faster growth of land prices than housing prices, a locationally steeper land rent gradient than the housing price gradient, and relatively flatter housing quantity and price gradients in larger cities with flatter population gradients. The calibrated model is then used to quantitatively assess the dynamic and spatial consequences of demand and supply shifts. We find that nonhomotheticity in forms of income-elastic spending on housing/household durables and minimum structure requirement in housing production are essential ingredients.

草莓、桃、苹果等果实在生长后期和贮藏过程中逐渐软化,而柑橘类特别是柚在成熟后期和贮藏过程中出现粒化,严重影响其经济价值.本研究分析和鉴定了柚基因组中多聚半乳糖醛酸酶基因(CgPG)家族成员以及PG酶活的变化,旨在揭示柚果实成熟过程中CgPG表达与汁胞粒化形成的关系.本研究对柚基因组库中CgPG基因家族成员的数量、基因定位、基因结构进行生物信息学分析,并对CgPG基因家族成员进行了表达鉴定,同时测定了汁胞粒化程度以及PG活性.结果表明:从柚全基因组鉴定出26个CgPG基因,进化树分析聚类为6个亚类(Group A～Group F),除E类外,所有外显子,内含子结构和基序基本上都是保守的,Group E中的CgPG26的GDDC结构域突变为GDDA,SPNTDGI突变为APNTDGI;CgPG基因主要分布于1、2、4、5、7、9号染色体上,在2和5号染色体上都有5～6条基因的串联复制;Group A和Group B与果实成熟有关,Group A中的CgPG5和Group B中的CgPG1、CgPG24参与了果实成熟和汁胞软化,CgPG13、CgPG12、CgPG26参与柚粒化过程中的果胶降解和细胞壁稳态调节;通过表达分析,Group A中的CgPG5和Group B中的CgPG1、CgPG24可能参与了柚不易粒化果成熟过程中汁胞的软化和最后腐败,基因的显著表达表明汁胞走向衰败;Group D中的CgPG13和Group E中的CgPG12、CgPG263个基因可能参与了柚易粒化果成熟过程中的果胶暂时降解,基因的高表达使汁胞软化,此时正是食用的最佳时期,随后在汁胞粒化过程中基因表达显著下降.因此,CgPG基因表达呈现不同的趋势表明CgPG基因在不易粒化果和易粒化果中可能属于2个不同的调节系统,其中CgPG5、CgPG1、CgPG24属于柚成熟后期汁胞软化的果胶降解系统,CgPG13、CgPG12、CgPG26属于柚粒化的细胞壁稳态调节系统.

We develop a unified theory with endogenous technology choice in human/knowledge capital accumulation to obtain a rich array of development paradigms. The transition from a less productive technology to a more productive one occurs via endogenous technology choice without requiring any force of big push. However, technologies that are more productive face higher scale barriers and thus multiple steady states may appear with each of which being associated with a different technology. We characterize global dynamics and establish conditions under which middle-income trap or flying geese growth may arise in equilibrium. By calibrating the general model to the data from several representative economies at different development stages with different growth patterns, we identify various prolonged flying geese episodes and middle-income traps. The analysis shows that while improving the efficacy of human capital accumulation is more crucial for advanced and fast-growing economies, mitigating barriers to human capital accumulation is more rewarding for emerging growing economies and development laggards. Our growth accounting results indicate that once the efficacy of and the barriers to human capital accumulation are incorporated, the residual TFP component no longer plays a substantial quantitative role.

对福建省平和县100 m和500 m不同海拔'琯溪蜜柚'结果母枝春梢直径生长、花芽分化过程开展研究,以探寻不同海拔对花芽分化的影响,为不同海拔蜜柚采用环剥促花措施时期提供依据.结果表明:在9月底不同海拔的蜜柚都有少数芽开始花芽生理分化,花原基渐渐形成;当春梢直径增长率经历一个高峰值后,花芽生理分化开始加速;同一时期,低海拔蜜柚花芽分化率高于高海拔;当春梢直径进入一个增长率为1.4％左右的低速期时,花芽分化进入形态分化阶段;不同海拔蜜柚在达到相同花芽分化率(大于35％)的时间差、进入低增长率时间差、进入形态分化的时间差和开花时间差大致吻合,低、高海拔大约相差14 d.花芽生理分化阶段和形态分化的初始阶段对蜜柚树体进行环剥可以提高花和果实的数量,提早开花,使果实成熟期提前,并且环剥时间越早越明显.由此,相对于传统的12月中旬蜜柚环剥促花措施,低海拔可提前至10月中旬,高海拔在11月初左右,环剥促花效果好且能使果实提前成熟.

[目的]探讨蜜广橘果皮在裂果发生期间活性氧代谢和相关抗氧化基因的变化,为蜜广橘合理减缓裂果发生提供理论依据.[方法]以易裂果的蜜广橘果皮作为试验材料,设置3个试验处理:清水处理、0.14g·L-1Ca(Ca)、0.14g·L-1 Ca+2×10-5吲哚乙酸(3-Indoleacetic acid,IAA)(Ca+IAA),在5、6月进行叶面喷施,通过测定O2·-、H2O2和丙二醛(malo-ndialdehyde,MDA)含量,相关基因CsSOD、CsCAT、CsPOD、CsAPX和CsGPX等表达及其酶活性的变化,分析不同钙(Ca、Ca+IAA)处理对其裂果率的影响.[结果]裂果果皮中O2·-、H2O2和MDA含量始终高于正常果,钙处理降低了 O2·-、H2O2、MDA含量和过氧化物酶(peroxidase,POD)活性,提高了超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)、抗坏血酸过氧化物酶(aseorbateperoxidase,APX)、谷胱甘肽过氧化物酶(glutathione peroxidase,GPX)活性,减轻了细胞损伤,从而有效预防了裂果的发生,其中Ca+IAA处理的效果更好.相关抗氧化基因在正常果中相对表达量均高于裂果,但CsPOD基因的相对表达量低于裂果,这与相关抗氧化酶活性的变化保持一致.[结论]在裂果爆发期的8、9月份,果皮活性氧含量最高,通过钙处理可显著提高果皮抗氧化相关基因的表达,提高其抗氧化酶活性并清除活性氧,维持植物细胞活性氧代谢平衡,减轻蜜广橘裂果率,为生产上预防裂果提供理论依据.

[目的]探究琯溪蜜柚汁胞粒化与次生壁纤维素含量、自由水和束缚水含量、品质等指标的相关性以及纤维素合成酶基因表达情况,以期为汁胞粒化过程中次生壁形成的分子调控机制研究提供依据.[方法]选取2018年8、9、10和11月4个时期的琯溪蜜柚果实,测定汁胞粒化率、可溶性固形物(total soluble solid,TSS)、可滴定酸(titratable acid,TA)、含水量和纤维素含量.从汁胞转录组中筛选差异表达的纤维素合酶基因(cellulose synthase,CESA)并进行分类和表达分析.[结果]琯溪蜜柚果实10月后,果实横径迅速增加,汁胞粒化明显加速,单汁胞粒化严重,纤维素、TA和束缚水含量显著上升,果形指数和自由水含量明显下降;转录组筛选差异基因CrCESA4、CrCESA7-1和CrCESA8分别与拟南芥AtCESA4、陆地棉GhCESA7和拟南芥AtCESA8聚类在一起.CrCESA4、CrCESA-1、CrCESA8基因相对表达量在11月显著上升,相对表达量与转录组一致.[结论]汁胞粒化程度与纤维素、TA和束缚水含量呈正相关,与果形指数和自由水含量呈负相关;进化树、转录组和表达分析表明CrCESA4、CrCESA7-1、CrCESA8可能参与了汁胞粒化过程中次生壁纤维素的合成.

为分析“红橘”种质资源,利用ISSR分子标记对33份“红橘”种质资源进行遗传多样性分析,利用NTsys 2.10e构建UPGMA树状图,从27条引物中筛选出14条,对33份“红橘',种质资源的DNA进行PCR扩增,得到148条谱带.其中多态性条带120条,多态位点百分率80.53％.33份“红橘''种质资源的遗传相似系数在0.570～0.970之间.以遗传相似系数0.780为阈值,将33份“红橘'种质资源划分为7个组(A,B,C,D,E,F,G).该研究结果表明33份种质资源遗传差异较大,ISSR能较好地将它们区分开,有助于福橘果实品质改良和福建省红橘种质资源的发展.

本研究以大棚延后栽培的'南丰蜜橘'作为研究材料,结合覆盖材料与保水剂做树盘试验处理,分析不同树盘处理对浮皮程度、果实品质和树盘土壤温湿度的影响.结果表明:在果实成熟的11月,树盘覆盖处理可提升果实可溶性固形物(TSS)、可滴定酸(TA)和维生素C含量,反光膜+保水剂处理提升果实TSS和TA效果显著,分别较对照(CK)高2.30％、0.27％.果实浮皮程度与TSS、TA和维生素C含量负相关;在12月,CK和稻草处理果实TSS、TA含量低,浮皮趋于严重,浮皮程度分别高达1.67级、1.07级,而其他处理果实出现轻度浮皮,均为0.73级.浮皮程度与单果重、果实 TA 和维生素 C 含量有很大关联性;在翌年 1月,浮皮程度与土壤湿度呈极显著正相关(相关系数为0.879),而TA与土壤湿度呈极显著负相关(相关系数为-0.911).反光膜+保水剂处理土壤湿度一直处于最高,此时期TA迅速降低,浮皮程度呈加速趋势.因此,土壤湿度越高,浮皮程度越严重,果实的TSS、TA和维生素C含量越低.通过覆盖处理能降低土壤湿度,提升果实TSS、TA和维生素C含量等品质,推迟'南丰蜜橘'果实浮皮的发生,减轻果实浮皮程度.其中,地布覆盖处理防治果实浮皮效果最佳,反光膜、地毯、地布+保水剂处理的效果次之.

Combining with the Salop model, the horizontal competition between one dual-channel retailer and N − 1 traditional retailers is studied in a circular market where all the retailers are uniformly located. The dual-channel retailer set different pricing strategies and unified pricing strategy for products selling online and offline respectively when physical channel has congestion negative effect. This paper studies the impact of congestion negative effects on the physical channel and the effect of the number of firms on channel pricing strategies in the circular market and to illustrate the results by using numerical experiments. The results show that: (i) traditional retailers should speed up the transformation from entities to dual-channel retailers and improve their service level; (ii) the dual-channel retailer should make different pricing for products which selling online and offline; (iii) and the newly entered traditional retailers will compete for the online market share, but has no effect on offline channel.

: We develop a model of trade and agglomeration that incorporates trade in both intermediate goods and fi nal goods and allows all fi rms to choose their locations. There are two types of labor: skilled labor, which is mobile, and unskilled labor, which is immobile. Upon choosing its factory site, a fi nal goods fi rm that is managed by skilled labor can produce these goods using local unskilled labor and a variety of intermediate goods produced by productivity-heterogeneous producers. We characterize world equilibrium and establish the conditions under which industrial agglomeration arises as a stable equilibrium outcome. We show that when the unskilled labor force is small, the role played by the selection of intermediate fi rms becomes less important, and trade liberalization induces dispersion. When the unskilled labor force is large and the selection e ff ect becomes in fl uential, trade liberalization can generate non-monotonic e ff ects on industrial agglomeration. The dispersion e ff ect of trade liberalization arises when unskilled labor-intermediate input complementarity matters to fi rm selection to a greater degree. When this is the case, trade liberalization may induce less selective fi rm entry and cause average productivity to fall.

通过比较分析番木瓜ERF家族成员的系统进化关系、基本理化性质、保守基序、启动子顺式元件,结合分析番木瓜在乙烯利和乙烯抑制剂1-甲基环丙烯(1-MCP)处理下以及不同成熟期果肉的RNA-seq数据,筛选出22个ERF家族成员进行表达差异分析,最终比较得出两个处理数据中显著差异表达基因有18个,推测这些基因可能在番木瓜果实成熟过程中起重要作用.

We consider an overlapping generations model with a durable local public good (DLPG). We establish a Tiebout theorem (equilibrium exists and is first best) as well as an equal treatment Second Welfare Theorem in this dynamic DLPG economy. We establish conditions, including the Small Jurisdiction assumption, under which local provision of durable public goods results in the full internalization of the intergenerational spillovers that durability entails. In contrast, when durable public goods are provided by the national government, internalization does not take place and underprovision of public goods results. This sets up an institutional trade-off between national and local provision of public goods that balances the relative strength of intergenerational and interjurisdictional spillovers. Our main conclusion is that while capitalization is an effective mechanism to cause agents to internalize intergenerational spillovers, the effectiveness of this mechanism is limited by the degree to which there are more general spillovers across jurisdictions.

Interspecific hybridization is an effective strategy for germplasm innovation in sugarcane. Nobilization refers to the breeding theory of development and utilization of wild germplasm. Saccharum spontaneum is the main donor of resistance and adaptive genes in the nobilization breeding process. Chromosome transfer in sugarcane is complicated; thus, research of different inheritance patterns can provide guidance for optimal sugarcane breeding.