循环水养殖系统中饲养密度对罗非鱼幼鱼生长及经济效益的影响

为探讨养殖密度对循环水养殖系统中罗非鱼幼鱼的影响,选取了同批次的罗非鱼幼鱼进行50天的饲养,测定了4组不同养殖密度梯度下幼鱼的生长指标的变化,并计算了不同工况下的经济效益。结果表明,养殖密度对罗非鱼幼鱼的生长有一定的影响,随着养殖密度的增大,幼鱼的成活率及最终平均体重和体长都呈现出下降的趋势,特定生长率、日平均增重、生长效率、肥满度等生长指标也显示出相似的规律,密度最低的A组各生长指标显著高于密度最高的D组,密度过高会抑制罗非鱼幼鱼的个体生长速度。养殖经济效益分析表明C组产量最高,是较适宜的养殖密度。     

气象条件对海南省红厚壳生长的影响

分析研究了红厚壳生长与气象条件的关系。通过简单相关及逐步回归分析,建立了红厚壳的围径、株高生长量与气象条件间的数学模拟模型,结合红厚壳叶片的生长情况,得出了红厚壳生长适宜的气象条件指标。研究发现最适宜红厚壳生长的条件是：月平均气温25℃以上,最低气温18℃以上,降水量160mm以上,地表温度低于33℃,蒸发量在200mm以下。当最低气温小于10℃,降水量低于50mm时,红厚壳出现不抽芽的现象。     

Effect of the Russian Wheat Aphid on the Composition and Synthesis of Water Soluble Proteins in Resistant and Susceptible Wheat

The effect of Russian wheat aphid ( Diuraphis noxia) infestation on polypeptide composition and protein synthesis in the presence or absence of chloramphenicol and cycloheximide were studied in genetically comparable wheat ( Triticum aestvum) resistant (cv. PI 137739/5* Tugela) and susceptible (cv. Tugela) to the aphid. The aim is to gain information of molecular nature on the resistance phenomenon which may promote future breeding programmes. In the absence of feeding aphids polypeptide profiles of the two wheat lines were similar indicating the absence or presence at low levels of a constitutive resistance factor. Aphid infestation induced enhanced expression of certain genes in the resistant wheat only. A 100 kD nuclear encoded polypeptide is strongly induced in the resistant wheat. It is also evident that the synthesis of a 56 kD organel encoded polypeptide is suppressed by the feeding aphids in the susceptible wheat.     

长江经济带能源消费和经济增长的灰色关联分析

为深入了解长江经济带能源消费与经济增长的关系,本文基于灰色关联分析模型,利用1995-2015年能源消费与经济增长相关数据,对长江经济带能源消费与经济增长的相关性进行实证分析。结果表明: 在能源消费产业中,批发、零售业和住宿、餐饮业能源消费与经济增长的关联度最大,为0.88,农业、工业能源消费与经济增长的关联度最小,分别为0.50、0.52;在能源消费品种中,煤碳消费量与经济增长的关联度相对较小;以天然气和电力为代表的优质能源与经济增长具有显著的关联度。长江经济带应着力调整产业结构、优化能源消费结构,以实现绿色低碳循环发展。     

Estimating the economic effects of US state and local fiscal policy: A synthetic control method matching-regression approach

In this paper, we advance the empirical literature on US state and local fiscal policymaking by using the synthetic control method (SCM) to create pairwise matches for states in subsequent regression analysis of the relationships between state and local fiscal policies and several state economic outcomes. Additional contributions include the use of principal component analysis to construct broader narratives of state economic performance and to reduce the dimensionality of the characteristics used in SCM matching, while the regressions also include variables to control for post-matching economic shocks. Compared to conventional regression analysis, the SCM matching-regression approach better addresses potential endogeneity, reduces interpolation bias, and creates fiscal policy measures that better reflect policy differences. The SCM-matched regressions produce more statistically significant relationships between state and local fiscal variables and economic outcomes than do the conventional unmatched regressions, suggesting improved identification of state and local fiscal policy effects on economic outcomes. Robust relationships found include negative economic effects of the own-source revenue burden and property taxes. Consistent with the existing literature, the estimated fiscal policy effects are quantitatively small and unlikely to drive differences in state economic performance.     

椰园养鸡对椰园生态及其经济效益的影响

椰园养鸡能明显促进椰子叶片生长和提高椰子产果量,试验三年后,椰树年均新抽叶片数为13.58片,椰树年均产果量为80.2公斤。养鸡椰园具有一定的抗病虫草害作用,三年后,病虫草害种类明显减少、常见病虫害发生率及杂草存活率均为最低。椰园养鸡能提高椰园土壤肥力和改善椰树叶片养分,还能取得良好的经济效益,三年可获利润145440元/hm2。     

棉花花生间作复合系统的照度、生长发育与生产力效应

摘 要：洞庭湖平原是我国的高产棉区之一,随着杂交棉的推广,种植密度大幅降低,为农作物多熟复种提供了条件。本研究运用作物生态位差异等原理,选择3个花生品种即湘花120（繁茂度高、中早熟、大果）、四粒红（繁茂度中、特早熟、中果）、湘农小花生（繁茂度低、早熟、小果）,与长江流域的主要杂交棉品种湘杂棉2号进行间种,探讨了棉地间作花生的可行性。结果表明：1）间作棉花的相对照度、生长势、产量（3.4%～5.7%）均有所降低,而间作花生的相对照度提高,产量主要因为间作田花生基本苗减少而降低;2）不同花生品种对间作棉花的影响主要与繁茂度有关,以湘花120＞四粒红＞湘农小花生,而不同花生品种受棉花的影响主要与熟期有关,以湘花120＞湘农小花生＞四粒红;3）虽然间作棉花略有减产,但全田整体效益大幅增长,其中比花生单作增长35.9%～107.6%,比棉花单作增长31.6%～52.9%。因此,棉田间作花生在经济上不仅可行,而且大有可为。其中湘花120与棉花间作的整体效益最高。     

北京沟域经济发展模式的典型调研与思考

沟域经济发展模式对北京山区经济发展和实现城乡统筹发展目标具有重要意义。研究典型沟域经济发展的成功经验、面临问题和有关政策需求等,将为山区经济建设工作提供可借鉴经验和参考。本文采用走访、问卷和座谈等方式,对北京市2011年率先启动的7条重点沟域进行了调研。调研显示,重点沟域经济建设,在选择主导产业、改善生态环境、建设新村民居和促进山区经济建设等方面取得了显著成绩,但在理论探索、模式创新、生态保护、缩小城乡差距等方面仍有不足,需要不断加强理论研究、培育主导产业、促进农业体质增效和完善土地管理政策。     

Effects of the Russian wheat aphid on osmotic potential and fructan content of winter wheat seedlings

Summary The effect of an autumn Russian wheat aphid, Diuraphis noxia (Mordvilko), infestation on winter wheat, Triticum aestivum L., was investigated using osmotic potential, fructan content and field survival measurements to estimate coldhardiness. An average infestation of 147 aphids per plant, under simulated hardening conditions, increased the osmotic potential of Froid and Brawny (more or less coldhardy varieties, respectively) seedlings by 0.236 and 0.345 MPa, respectively. A natural field infestation averaging 9.7 aphids per plant reduced fructan contents of Froid and Brawny seedlings by 22.60 and 59.10 g kg^-1 dry wt., respectively. Similar trends occurred after a natural freeze period. Field survival and yield results indicate that the autumn infestation reduced the winter survivability of Brawny by 54% and reduced grain yields by 1217 kg ha^-1; survival and yield of infested Froid were not significantly affected. PI 372129, a D. noxia resistant winter wheat genotype was not affected by an infestation in regard to these parameters. These studies suggest that coldhardiness in Froid and Brawny was reduced by D. noxia though only the less hardy Brawny had a significantly reduced winter survivability and grain yield. Therefore, the effects of an autumn D. noxia infestation on some winter wheat genotypes may interact with a winter climate and increase the potential for winterkill.     

无蔗糖培养和不同封口膜对非洲菊组培苗生长的影响研究

研究了培养基中有蔗糖与无糖、容器封口膜密封和带滤菌膜透气对非洲菊组培苗增殖、鲜重、干重和根系形成等的影响。生根培养阶段的非洲菊试管苗能生长在无蔗糖培养基上。用带滤菌膜可透气封口膜可以明显提高组培苗的鲜重增量和干重率,促进根系的形成和生长,提高在无糖培养下的苗的存活力和质量,延长组培苗的留瓶时间。透气状况的改善也可提高增殖培养的效率。结果表明组培苗具有一定光自养生长潜能,改进培养条件可提高培养效率和种苗质量     

农大哥复合生物肥对桃树生长、产量和品质的影响

本试验以桃王九九品种为试验材料,研究分析了农大哥复合生物肥对桃树生长、产量和品质的影响。结果表明：施用复合生物肥可以显著提高桃树营养枝春梢的长度和粗度,而对秋梢的长势无显著影响;增施复合生物菌肥后,桃树单株坐果数、单果重量和平均株产均明显提高,维生素C、可溶性固形物、可溶性糖和有机酸的含量以及糖/酸比值都明显上升,提高了果实产量和品质。     

Economic liberalization and external shocks. The hypothesis of convergence revisited for the Mexican states, 1994–2015

We study the convergence hypothesis for Mexican states during the period 1994–2015 considering the impact not only of NAFTA but also of other external shocks, such as China’s entry into the World Trade Organization (WTO) in 2001 and the global financial crisis of 2008. Using econometric panel data models with no fixed effects to avoid small sample bias, the main results indicate: (a) presence of absolute divergence, consistent with a sigma process divergence, particularly in the period after the outbreak of the global crisis of 2008; and (b) a process of weakening conditional convergence across the sub‐periods analyzed.     

作物生长调节剂对小麦抗倒性和产量的影响

为给高产小麦抗倒防衰提供理论和技术支持,以高产、高杆、抗倒性差品种烟农19为材料,研究了不同种植密度下,植物生长调节剂（壮丰安、稀效唑、国光矮丰和爱久收）以及传统的镇压措施对小麦最终产量、茎秆形态结构和物理性状的影响。结果表明,和225×104 ha-1的基本苗相比,270×104 ha-1的基本苗植株高度增加,且籽粒产量、茎节粗度、茎秆充实度和抗倒伏指数降低;返青期喷施壮丰安、烯效唑和国光矮丰或者人工镇压都可降低小麦基部节间的长度,增加其粗度和充实度;拔节期喷施爱久收可缩短小麦穗下节间长度、增加其粗度和充实度,最终各调控措施下小麦茎秆重心高度降低,抗倒指数增加,尤其在较高基本苗条件下;喷施壮丰安和爱久收降低了小麦最终植株高度;喷施烯效唑和爱久收提高了小麦千粒重和产量,国光矮丰和镇压措施对最终产量无显著影响,而壮丰安降低了低密度群体小麦千粒重和产量。     

The impact of external knowledge sourcing on innovation outcomes in rural and urban businesses in the U.S.

This paper examines the relationship between external knowledge sourcing and a diverse set of innovation outcomes in rural and urban establishments in the U.S. Existing studies in the broader knowledge management literature principally examine firms in a single industry, overwhelmingly rely on patent data to proxy for innovation, and cannot account for the innovations of businesses in rural American markets. By addressing these limitations using data from the 2014 Rural Establishment Innovation Survey of the USDA's Economic Research Service, this research provides novel insights into how externally acquired knowledge by American establishments may support innovation. Results of the analysis suggest that external knowledge sourcing may specifically promote product, process, and green innovation in U.S. firms. While collective results when external sources of information are divided by industry orientation fail to show that sources outside of a firm's industry play a dominant role in the innovation processes of American establishments in general, findings provide evidence for an outsized impact of these relationships within rural establishments specifically and suggest that external knowledge sourcing from extra‐industry organizations is most critical for promoting successful innovation in rural firms. Results additionally indicate that knowledge sourcing from non‐local organizations may be more important for supporting innovation in rural compared to urban markets.     

Analysis on the Track of Chinese Financial Development and Economic Growth

This paper discussed the long-run relationship between financial development and economic growth of china is examined in a multivariate vector auto regression (VAR) framework. And validate whether the economics of china according with hypothesis brought forward by the economist of Yale University Hugh T. Patrick. And the hypothesis was from two theories; one is "demand-following"; the other is "supply-leading". The conclusion of this paper examines the economic growth of China is true of the hypothesis.     

农业专业期刊刊群建立初探——基于促进农业科技知识传播的视角

为促进农业科技知识传播,同时做大做强科技期刊,针对传统农业科技知识传播方式不足的问题,提出整合行业期刊资源建立农业专业期刊刊群的建议,从入群期刊筛选、期刊网站构建及运营角度进行初步探讨。农业专业期刊刊群具有行业知识全面、可持续更新、免费共享、流量平台化的优势,在创新农业科技知识传播方式的基础上,通过广告运营实现期刊刊群的可持续发展。     

番木瓜对不同施肥模式的响应及经济效益分析

为了探讨番木瓜高产高效栽培与合理施肥模式之间的平衡点,确保番木瓜高产优质,施肥模式经济高效。通过连续2年的田间小区定位试验,研究了5种不同施肥模式（专用肥,T1;专用肥+改良剂,T2;专用肥+精制有机肥,T3;精制有机肥,T4;生物有机肥,T5）对番木瓜营养生长、产量及品质的影响,开展了不同施肥模式的经济效益分析。结果表明：与T1处理对比,T2、T3处理均表现出促进番木瓜冠幅、株高生长增加的趋势。整个示范区番木瓜株产40.2~49.3 kg,平均单果重0.38~0.41 kg,单株收获商品果实105.8~120.4个。T3处理较T1处理增产18.6%,差异显著。糖度的方差分析结果显示,T1处理显著低于T4、T5处理,T4、T5处理均显著低于T2、T3处理。不同施肥模式鲜果肉维生素C含量与糖度的趋势一致。从经济效益来考察,T3处理获得的净产值最高（413819元/hm2）,产投比为T3≈T2>T5≈T1>T4处理。     

基于生育期模型的鄂西高山地区辣椒种植研究

为了更合理有效利用山区特有气候资源,提高高山地区辣椒产量及菜农收入,利用2009—2013年在鄂西南山区不同高度不同时间栽培试验及同步气象观测资料,建立了基于光温效应的高山辣椒生育期模型,分析了开花结果期累计光温效应APTE与单株坐果数、辣椒单产相关性,以及鄂西南山区相关气候特征。结果表明,生育期模型对生育期推算明显高于有效积温的推算;单株坐果数、辣椒单产与开花结果期≥16℃持续时间、APTE有显著的正相关;鄂西南海拔800 m高度≥16 ℃持续天数最长,且无高温天气过程出现,1200 m以上高海拔地区辣椒适宜开花结果期短,800~1200 m是鄂西南山区反季节辣椒生产的最佳高度带。800 m以上的中高山地区可以通过保护措施提早辣椒开花结果,从而延长开花结果期,增加辣椒产量。     

多功能高分子植物生长调节剂在干旱区玉米生产上的试验效果初报

报道了以观测记录和拍照方式研究多功能高分子植物生长调节剂对玉米生长和繁殖的影响结果，分别用玉米生长、结实和产量指标、玉米品质指标以及经济效益指标与对照比较以评定试验效果。结果显示，施用试剂有利于玉米的营养和结实生长，使玉米产量增加11.06%、品质有所改善（试验组玉米粗蛋白和粗脂肪含量有所提升），经济效益有所提高，仅仅考虑增产就净增产值607.95元/hm2。     

不同接穗长度和栽种时间对杨梅嫁接成活率及生长量影响的研究

为提高杨梅嫁接成活率和接穗利用率,2014年开展了不同接穗长度、不同栽种时间对杨梅嫁接成活率和生长量影响的研究。结果表明,杨梅嫁接后6d、12d栽种的,5--6㎝短穗嫁接的成活率达87%和88%,略低于8-12㎝长穗嫁接的89%和90%,二者差异不极显著;嫁接后6d、12d栽种的成活达87%-90%,极显著高于嫁接后1d栽种的20.2%-21%。研究认为,在嫁接后遇下雨天气,根据天气情况,在接后6d-12d内选择晴天栽种,可显著提高成活率;在接穗紧缺时采用短穗嫁接,可大大提高接穗利用率。