Long-term downward trend in total solar irradiance

The first 5 years (from 1980 to 1985) of total solar irradiance observations by the first Active Cavity Radiometer Irradiance Monitor (ACRIM I) experiment on board the Solar Maximum Mission spacecraft show a clearly defined downward trend of -0.019% per year. The existence of this trend has been confirmed by the internal self-calibrations of ACRIM I, by independent measurements from sounding rockets and balloons, and by observations from the Nimbus-7 spacecraft. The trend appears to be due to unpredicted variations of solar luminosity on time scales of years, and it may be related to solar cycle magnetic activity.     

Astronomy and solar physics: solar irradiance observations

The absolute radiometer on Spacelab 1 was used to obtain solar irradiance observations from space. A number of effects must be taken into account in the data reduction. A provisional value was obtained for the mean solar constant during the observation period (6 to 8 December 1983).     

Observations of solar irradiance variability

High-precision measurements of total solar irradiance, made by the active cavity radiometer irradiance monitor on the Solar Maximum Mission satellite, show the irradiance to have been variable throughout the first 153 days of observations. The corrected data resolve orbit-to-orbit variations with uncertainties as small as 0.001 percent. Irradiance fluctuations are typical of a band-limited noise spectrum with high-frequency cutoff near 0.15 day(-1) their amplitudes about the mean value of 1368.31 watts per square meter approach +/- 0.05 percent. Two large decreases in irrradiance of up to 0.2 percent lasting about 1 week are highly correlated with the development of sunspot groups. The magnitude and time scale of the irradiance variability suggest that considerable energy storage occurs within the convection zone in solar active regions.     

Astronomy and solar physics: measurement of the solar spectral irradiance from 200 to 3000 nanometers

The solar spectrum experiment on Spacelab 1 measured 98 percent of the sun's total energy output. It improved the absolute accuracy of solar irradiance data, especially in the ultraviolet and infrared regions. In order to detect any variation in the spectrum on future shuttle flights, the data were obtained in a radiation scale that can be preserved with high precision over many years. The instrument performance and preliminary data reduction are described.     

我国城乡居民消费差异-基于四变量误差修正模型的实证分析

利用中国1991—2008年时间序列数据,分析中国城镇和农村地区居民消费差异,所使用的分析方法包括ADF平稳性检验,协整检验以及四变量误差修正模型,Chow检验。分析结果表明,中国城镇和农村地区同时存在消费与收入的长期均衡关系,消费物价水平的上升及政府补贴政策对提高城乡居民收入弹性有间接的正向效应,其中对城镇居民收入弹性的正向效应大于农村居民,另外城乡居民的消费行为存在结构稳定性。     

An empirical model for predicting diffusion coefficients in silicate minerals

An empirical model describing the diffusion kinetics of oxygen in silicate minerals under hydrothermal conditions has been established for temperatures between 773 and 1073 Kelvin at 100 megapascals of water pressure. The equation, log D = alpha + (beta/T) + [(gamma + (delta/T))Z], where D is the diffusion coefficient, alpha, beta, gamma, and delta are constants, T is the Kelvin temperature, and Z is the total ionic porosity, may be used to predict diffusion coefficients, in most cases to within the reported experimental reproducibility of a factor of 2. For oxygen diffusion, alpha = -2, beta = -3.4 x 10(4)K, gamma = -0.13, and delta = 6.4 x 10(2)K, for D in square centimeters per second. Limited data for the diffusion of argon in silicates suggest that the model describes this system as well.     

土地财政与土地城镇化互动关系研究——基于VAR模型的实证分析

为考察土地财政与土地城镇化的互动关系,本研究在理论分析的基础上,采用计量经济分析方法对中国1999—2015年省级层面二者关系进行了检验。研究结果表明:1)土地财政与土地城镇化具有双向互动关系,可分为引致用地需求、土地城镇化扩张和土地财政再扩充3个阶段;2)实证分析显示,土地财政和土地城镇化存在相互促进的统计学关系,土地城镇化进程在短期内会引起土地财政的逐渐增加,而土地财政对于土地城镇化有长期的持续性正向影响,分别与理论分析中的3个阶段相匹配;3)脉冲响应和方差分解的结果均显示土地城镇化对土地财政冲击的响应较为灵敏和强烈,说明土地财政显著影响了我国的土地城镇化进程。地方政府应积极推进土地财税制度改革,严格把控城市拓展边界,最大限度地发挥城市土地的价值。     

Direct measurement of solar luminosity variation

Two rocket flights of an absolute pyrheliometer, separated by 30 months, indicate an increase in solar luminosity (solar constant) of 0.4 percent. The significance of this result is considered in light of the instrument performance during the rocket flights and of pre- and postflight intercomparisons with independently maintained pyrheliometers. There is a high probability that the measured difference is real. Additional observations are required to determine whether the difference results from random fluctuations in solar luminosity, a nonrandom change of short duration, or a sustained change that has climatological significance.     

A model of solar luminosity modulation by magnetic activity between 1954 and 1984

A simple model based on the changes in excess radiation from bright magnetic faculae and on changes in reduced radiation from dark spots is remarkably successful in matching the slow variations of total solar irradiance measured simultaneously by the ERB and ACRIM satellite radiometers between 1981 and 1984. This model was extended back to 1954 to reconstruct the modulation of irradiance by magnetic activity during the past three 11-year solar cycles. The model predicts that the sun is consistently brighter at activity maximum than at minimum. The 0.07 percent brightening at the peak of the last cycle in 1980 was more pronounced than the brightenings found for either of the two previous cycles, even though cycle 19, which peaked around 1957, had the largest sunspot number amplitude in the history of reliable sunspot records.     

陕西省旅游业与经济增长关系的实证研究

选取1991—2007年陕西省旅游业及经济增长的时间序列数据,借助Eviews软件,用Granger因果检验等方法对GDP与旅游业总收入两者之间的关系进行量化分析,建立了GDP与旅游业的向量自回归模型,得出了从长期来看陕西省旅游业与经济增长互为因果关系的结论,并提出了促进陕西省旅游业发展的政策建议。     

金融发展对城乡居民收入差距关系的实证研究

我国金融行业的发展迅猛,但同时也暴露了金融迅猛发展带来的“城乡居民收入差距 的不断拉大以及贫富分化更加严重”等弊端。本文利用中国1995 年—2016 年2 的样本数据,建 立VAR 模型进行实证研究。结果表明,金融发展规模的扩大会造成城乡居民收入差距的扩大, 金融效率的不断提高可以逐渐缩小城乡居民收入差距。     

Efficiency of convection and time variation of the solar constant

Variations in the efficiency of convection resulting from its stochastic nature could be manifested as small ( less, similar1 percent) fluctuations in the solar constant. This could result in changes in the earth's climate with time scales of decades to centuries.     

绛县山楂产业集群与经济增长关系的实证研究

选取1992—2008年绛县山楂收入及经济增长的时间序列数据,借助Eviews软件,用Granger因果检验等方法对GDP与山楂产业集群总收入两者之间的关系进行量化分析,建立GDP与山楂产业集群的向量自回归模型,得出了从长期来看山楂产业集群与经济增长互为因果关系的结论,并提出了促进绛县山楂产业集群发展的政策建议。     

海南省农民收入与农村信贷关系的实证研究

利用自回归模型、脉冲响应函数和预测方差分解对海南省1988—2008年农民收入与农村信贷之间的关系进行了实证分析。结果表明,农村信贷与农民收入之间存在着互动作用,增加农村信贷投入是促进农民收入持续增长的途径,而农民收入的增加也促进农村信贷的投入。但目前农村信贷对农民收入影响不是很显著,应建立长期有效的农村信贷投入机制,以促进农民收入的持续稳定增长。     

交通基础设施与森林公园旅游发展 ——基于面板联立方程的实证检验

交通基础设施既是旅游业发展的基础,也是旅游业"六要素"的一部分。通过文献梳理,在探讨交通基础设施建设与森林公园旅游发展相互作用机制的基础上,采用1998—2017年中国省级面板数据和面板联立方程模型,实证检验了两者的互动关系假说。结果表明,1)总体看,交通基础设施建设对森林公园旅游发展表现为较强的促进作用,但反方向的促进作用较弱。2)分森林公园类型看,交通基础设施建设仅分别与中资源比较优势区和资源利用不足型地区的森林公园旅游发展存在显著互动关系。3)分交通基础设施看,仅有公路交通建设与森林公园旅游发展存在显著正向的互动关系;1998—2007年时期,交通基础设施建设对森林公园旅游发展具有显著正向影响,但反向影响不显著。4)不同交通基础设施与不同森林公园类型的交叉组合看,铁路交通建设仅在森林公园的高资源比较优势区对旅游发展具有显著正向影响;公路交通建设对森林公园旅游发展均具有显著正向影响,其中,等级公路交通建设的影响更大。对此,需要因地制宜地完善交通基础设施建设、创新森林公园旅游业态。     

An empirical assessment of taxic paleobiology

The analysis of major changes in faunal diversity through time is a central theme of analytical paleobiology. The most important sources of data are literature-based compilations of stratigraphic ranges of fossil taxa. The levels of error in these compilations and the possible effects of such error have often been discussed but never directly assessed. We compared our comprehensive database of trilobites to the equivalent portion of J. J. Sepkoski Jr.'s widely used global genus database. More than 70% of entries in the global database are inaccurate; however, as predicted, the error is randomly distributed and does not introduce bias.     

Cyclic variation and solar forcing of Holocene climate in the Alaskan subarctic

High-resolution analyses of lake sediment from southwestern Alaska reveal cyclic variations in climate and ecosystems during the Holocene. These variations occurred with periodicities similar to those of solar activity and appear to be coherent with time series of the cosmogenic nuclides 14C and 10Be as well as North Atlantic drift ice. Our results imply that small variations in solar irradiance induced pronounced cyclic changes in northern high-latitude environments. They also provide evidence that centennial-scale shifts in the Holocene climate were similar between the subpolar regions of the North Atlantic and North Pacific, possibly because of Sun-ocean-climate linkages.     

African swine fever and meat prices fluctuation: An empirical study in China based on TVP-VAR model

African swine fever(ASF), a fatal disease outbroken in China in August 2018, has widely attracted social concern especially in the information era. The occurrence of ASF led to an imbalance between supply and demand in pork and other meat markets. As a result, meat prices fluctuated greatly during the past year in 2019. To measure ASF quantitatively, the internet public concern index about ASF was created using web crawler methods. The relationships between ASF and meat prices were analyzed based on time-varying parameter vector auto-regressive(TVP-VAR) model. The results showed that there were some differences in the impact size, direction and duration of ASF on the prices of pork, chicken, beef and mutton, and the characteristics of time variability and heterogeneity were obvious. At the same time, the impact of ASF on meat prices is not consistent with the trend and degree of ASF. The impulse intensity is strongly correlated with the strength and duration of ASF, and it is generally weak in the early stage and much stronger in the middle and late periods. The results indicate that macro regulations, monitoring and early-warning system, standardizing production and circulation, and the public opinion monitoring and guidance about ASF should be given more attention in future to stabilize the market expectations and to promote a smooth functioning of the livestock markets.     

市场化、财政支农与粮食产出——基于门槛模型的实证分析

为深入探索财政支农支出对粮食产出的影响规律,利用我国2000—2013年31个省份的面板数据样本,基于门槛模型对市场化背景下财政支农支出对我国粮食产出的影响及其区域差异进行了实证分析。结果表明:1)财政支农支出对粮食产出的影响受市场化水平的严重制约,表现出显著的非线性,存在双门槛效应,2个市场化门槛值分别为4.465及8.540。2)到2013年为止,我国已经有10个省份进入高市场化行列,19个省份为中等市场化省份,但是仍然有西藏、青海2个省份没有迈过低市场化门槛。3)财政支农支出的粮食产出效应存在显著的区域差异。在高市场化省份,财政支农支出对粮食产出的影响系数为0.393,具有显著的促进作用;在中等市场化省份,财政支农支出能够促进粮食产出,其影响系数为0.031,但是促进作用不显著;而在低市场化省份,财政支农支出对粮食产出的影响系数是-0.087,其效应显著为负。认为应该在市场化水平比较低的省份加快其市场化进程,进行制度创新,以更有效地实现财政支农促进粮食安全的政策目标。     

地表太阳辐射减弱和臭氧浓度增加对冬小麦生长和产量的影响

为研究辐射减弱和O3胁迫对作物的影响,利用改进的开顶式气室(OTC)和遮荫网,开展了辐射减弱和O3胁迫的大田试验研究.实验设置4种处理:CK为野外大田组,T1为40％遮荫,T2为100 nL/LO3,T3为遮荫40％和100 nL/LO3的复合组.结果表明:T1和T3组冬小麦的生育期延长且推迟,T3组株高无明显变化;T2组株高降低,生育期缩短;单株干物质重均降低,T3降幅最大;各组灌浆速率均降低,T3组降幅最大;T1和T3产量、千粒重、穗数、穗粒数和穗重显著降低,T2组穗数无明显改变.由此可见,复合对小麦生长的影响较接近40％遮荫;粒重降低主要是因为灌浆速率的降低,灌浆时间的影响较小;产量的降低主要是千粒重、穗数、穗重的降低,降幅最大,但小于两因子单独累加.