Lunar Fe and Ti abundances: comparison of lunar prospector and clementine data

The Lunar Prospector neutron spectrometer data correlate well with iron and titanium abundances obtained through analysis of Clementine spectral reflectance data. With the iron and titanium dependence removed, the neutron spectrometer data also reveal regions with enhanced amounts of gadolinium and samarium, incompatible rare earth elements that are enriched in the final phases of magma crystallization. These regions are found mainly around the ramparts of the Imbrium impact basin but not around the other basins, including the much larger and deeper South Pole-Aitken basin. This result confirms the compositional uniqueness of the surface and interior of the Imbrium region.     

Migration and Western europe: the old world turning new

The 1960s meant a historical turn of Western Europe, becoming an immigration area. Net immigration has been concentrated to some of the prosperous Western European countries and has been mainly determined by the demand of their particular national labor regimes. The size of alien employment has been very differently affected by the 1973 crisis, but a multiethnical society will remain a novel feature of most Western European countries. Political abdication from full employment and technological change makes a ghetto of un(der)employment a likely prospect of a large part of the second generation of recent immigrants into Western Europe.     

Protein deficiency and tribal warfare in Amazonia: new data

Increasing numbers of anthropological studies about native Amazonian warfare and demographic practices attempt to explain these phenomena as competition over or a response to scarce game animals and other sources of high-quality protein. Recently completed field research among the Yanomam? Indians living at the Venezuela-Brazil border indicates that their protein intake is comparable to that found in highly developed industrialized nations and as much as 200 percent more than many nutritional authorities recommend as daily allowances. Recent data on other Amazonian tribes likewise fails to indicate a correlation between protein intake and intensity of warfare patterns.     

Lunar surface magnetic fields and their interaction with the solar wind: results from lunar prospector

The magnetometer and electron reflectometer experiment on the Lunar Prospector spacecraft has obtained maps of lunar crustal magnetic fields and observed the interaction between the solar wind and regions of strong crustal magnetic fields at high selenographic latitude (30 degreesS to 80 degreesS) and low ( approximately 100 kilometers) altitude. Electron reflection maps of the regions antipodal to the Imbrium and Serenitatis impact basins, extending to 80 degreesS latitude, show that crustal magnetic fields fill most of the antipodal zones of those basins. This finding provides further evidence for the hypothesis that basin-forming impacts result in magnetization of the lunar crust at their antipodes. The crustal magnetic fields of the Imbrium antipode region are strong enough to deflect the solar wind and form a miniature (100 to several hundred kilometers across) magnetosphere, magnetosheath, and bow shock system.     

The Lunar Laser Ranging Experiment: Accurate ranges have given a large improvement in the lunar orbit and new selenophysical information

The lunar ranging measurements now being made at the McDonald Observatory have an accuracy of 1 nsec in round-trip travel time. This corresponds to 15 cm in the one-way distance. The use of lasers with pulse-lengths of less than 1 nsec is expected to give an accuracy of 2 to 3 cm in the next few years. A new station is under construction in Hawaii, and additional stations in other countries are either in operation or under development. It is hoped that these stations will form the basis for a worldwide network to determine polar motion and earth rotation on a regular basis, and will assist in providing information about movement of the tectonic plates making up the earth's surface. Several mobile lunar ranging stations with telescopes having diameters of 1.0 m or less could, in the future, greatly extend the information obtainable about motions within and between the tectonic plates. The data obtained so far by the McDonald Observatory have been used to generate a new lunar ephemeris based on direct numerical integration of the equations of motion for the moon and planets. With this ephemeris, the range to the three Apollo retro-reflectors can be fit to an accuracy of 5 m by adjusting the differences in moments of inertia of the moon about its principal axes, the selenocentric coordinates of the reflectors, and the McDonald longitude. The accuracy of fitting the results is limited currently by errors of the order of an arc second in the angular orientation of the moon, as derived from the best available theory of how the moon rotates in response to the torques acting on it. Both a new calculation of the moon's orientation as a function of time based on direct numerical integration of the torque equations and a new analytic theory of the moon's orientation are expected to be available soon, and to improve considerably the accuracy of fitting the data. The accuracy already achieved routinely in lunar laser ranging represents a hundredfold improvement over any previously available knowledge of the distance to points on the lunar surface. Already, extremely complex structure has been observed in the lunar rotation and significant improvement has been achieved in our knowledge of lunar orbit. The selenocentric coordinates of the retroreflectors give improved reference points for use in lunar mapping, and new information on the lunar mass distribution has been obtained. Beyond the applications discussed in this article, however, the history of science shows many cases of previously unknown, phenomena discovered as a consequence of major improvements in the accuracy of measurements. It will be interesting to see whether this once again proves the case as we acquire an extended series of lunar distance observations with decimetric and then centimetric accuracy.     

新型职业农民培育收入效应及其差异性研究——基于四川省的调查

新型职业农民培育是解决现代农业人力支撑的关键力量,是乡村振兴与农业农村现代化建设的重要任务。基于西南地区农业大省四川省新型职业农民的调查,运用内生转换模型(ESRM),分析新型职业农民培育收入效应,探讨不同类型和不同农业区域的新型职业农民培育收入效应差异性。结果表明,在不考虑新型职业农民类型与区域差异情况下,新型职业农民培育的农业收入平均值明显提高了2.71万元,农业收入高于平均水平的农户更有可能选择参与新型职业农民培育。年龄、文化程度、培训的经历和村级新型职业农民数量均对农户选择培育有显著正向影响;新型职业农民培训地点距离和家中有村干部则会抑制其选择培育。新型职业农民培育具有明显正向收入效应,但不同类型和不同农业区域培育收入效应存在一定差异。在类型方面,社会服务型的培育收入效应高于生产经营型和专业技能型新型职业农民;在农业区域方面,成都平原区新型职业农民培育收入效应高于盆周山区和丘陵地区。因此,建议进一步规范培育机制、促进新型职业农民分类培育和建立新型职业农民差异化扶持政策。     

Understanding the farm data lifecycle: collection,use, and impact of farm data on U.S. commercial corn and soybean farms

Precision Agriculture - Enthusiasm regarding the “digital agriculture” revolution is widespread, yet objective research on how commercial farms actually use data and data services...     

中国农村金融发展对农民收入增长的影响研究——基于2009—2018年数据的实证分析

基于中国农村2009—2018年的相关数据,运用VAR模型实证分析了农村总贷款额、农业保险赔付额、农业保险保费、农村地区国家财政支出4项指标和农民收入增长之间的关系.结果表明,农村金融发展水平对农民收入增长有促进作用,但并不十分明显,且在一定的时期内具有滞后性,随着稳健且持续的冲击后,农民收入得到改善.最后,针对此现状...     

环境规制对肉鸭养殖户兽药减量行为的影响——基于10省份调研数据

畜禽养殖兽药减量化对保障肉源性食品安全和减少养殖污染具有重要意义。本文基于10省份1 078户肉鸭养殖户调研数据,运用Probit模型、IV-Probit模型和调节效应模型实证分析约束型环境规制、激励型环境规制和引导型环境规制对肉鸭养殖户兽药减量行为的作用机制,并对引导型环境规制的调节效应进行了检验。结果表明：约束型环境规制、激励型环境规制和引导型环境规制均促进肉鸭养殖户实施兽药减量行为,其中,引导型环境规制对肉鸭养殖户兽药减量行为的促进作用最强,约束型环境规制次之,激励型环境规制的作用效果最弱。进一步研究发现,引导型环境规制在约束型环境规制对肉鸭养殖户兽药减量行为的影响中发挥调节作用。基于上述结果,提出应进一步完善肉鸭养殖户兽药减量行为的激励机制,探索多渠道宣传引导肉鸭养殖户实施兽药减量行为,并充分发挥引导型环境规制的调节作用等对策建议,以期为我国畜禽养殖业提质增效和健康发展提供借鉴。     

Microcracking and healing in granites: new evidence from cathodoluminescence

Quartz grains in granitic rocks usually have blue cathodoluminescence (CL). Within the blue-luminescing grains, there are often red-luminescing domains which are frequently impossible to detect without CL contrast. This finding suggests that the red-luminescing quartz is sealing preexisting mnicrocracks. The presence of these now-healed microcracks has important implications with respect to the role of pore fluid pressure and fluid transfer in metamorphism, the origih of granites, longperiod crustal deformation, earthquake mechanics, physical properties of rocks, and deep-seated geothermal energy.     

Venus: further evidence of impact cratering and tectonic activity from radar observations

Earth-based radar images at a resolution of 10 kilometers show a diverse surface terrain on Venus, probably produced by both impact events and tectonic activity. Only a small number of craters of apparent impact origin are seen. Large-scale features show lineaments and parallel ridges suggesting tectonic origins.     

Chicxulub multiring impact basin: size and other characteristics derived from gravity analysis

The buried Chicxulub impact structure in Mexico, which is linked to the Cretaceous- Tertiary (K-T) boundary layer, may be significantly larger than previously suspected. Reprocessed gravity data over Northern Yucatan reveal three major rings and parts of a fourth ring, spaced similarly to those observed at multiring impact basins on other planets. The outer ring, probably corresponding to the basin's topographic rim, is almost 300 kilometers in diameter, indicating that Chicxulub may be one of the largest impact structures produced in the inner solar system since the period of early bombardment ended nearly 4 billion years ago.     

新农村建设中的集体行动困境及其化解——基于对三明调研的实证分析

在对福建三明市辖区、市、县12个行政村进行调研、广泛收集资料的基础上，分析了三明的农村现状与基础。根据奥尔森的集体行动的逻辑理论，对新农村建设中出现的集体行动困境做了实证分析和理论阐述，并结合调研中的若干认识，最后提出新农村建设的长效机制探索。     

Band-gap engineering: from physics and materials to new semiconductor devices

Band-gap engineering is a powerful technique for the design of new semiconductor materials and devices. Heterojunctions and modern growth techniques, such as molecular beam epitaxy, allow band diagrams with nearly arbitrary and continuous band-gap variations to be made. The transport properties of electrons and holes can be independently and continuously tuned for a given application. A new generation of devices with unique capabilities, ranging from solid-state photomultipliers to resonant tunneling transistors, is emerging from this approach.     

中国矛茧蜂亚科一新记录属及一新种(膜翅目:茧蜂科)

我国首次发现断脉茧蜂属 H eterospilus Haliaday,本文记述了该属的属征、生物学及其分布 ,并报道一新种——网皱断脉茧蜂 H eterospiluscancellatusn.sp..模式标本保存于福建农林大学益虫室     

Adoption of small-scale irrigation technologies and its impact on land productivity: Evidence from Rwanda

In an attempt to identify solutions to the effects of erratic rainfall patterns and droughts that limit agricultural production growth, the Rwandan government has recently increased investments in irrigation development. In this study, we analyze the adoption of small-scale irrigation technologies (SSITs) and its impact on land productivity using cross-sectional data from a sample of 360 farmers in Rwanda. The study uses the propensity score matching technique to address potential self-selection bias. Our results reveal that adoption decisions are significantly influenced by factors such as education, farm size, group membership, gender, extension services, access to credit, access to weather forecast information, risk perceptions, access to a reliable source of water for irrigation, awareness of rainwater harvesting techniques, and awareness of subsidy programs. In addition, the results show that the adoption of SSITs has a significantly positive impact on land productivity. The study concludes with policy implications that highlight the need to promote the adoption of SSITs among farmers as a strategy to improve agricultural productivity and food security in Rwanda.     

The Structure of Ordinary Water: New data and interpretations are yielding new insights into this fascinating substance

The train of thought pursued in this article has led to the conclusion that the structure of cold water seems likely to consist, for the most part, of hydrogen-bonded, four-coordinated, framework regions, with interstitial monomers occupying some fraction of the cavities the framework encloses. The precise geometry of the framework has not been specified, but some evidence suggests that it is rather regular at low temperatures and becomes more random as the water gets warmer. These conclusions, meager as they are in comparison with what we shall eventually need to know about water, are still "subject to change without notice." Such a change would, for instance, be made necessary by the discrediting either of the data or of the interpretations on which the model is based. The discovery of new facts, or of new meanings in old facts, which were clearly in conflict with the model, would also make it necessary to modify, if not to abandon, it. Even this would be progress, however, for it would be another product of the method of drawing upon data from diverse sources and would be a further step toward the progressively more comprehensive model to which this method will lead and the progressively greater confidence we will be able to place in our conclusions.     

中国尖盲蜈蚣属一新种和一新记录种(唇足纲:蜈蚣目:尖盲蜈蚣科)

记述了中国唇足纲Chilopoda,尖盲蜈蚣科Scolopocrytopidae,尖盲蜈蚣属Scolopocryptops的3种：黑斑尖盲蜈蚣,新种S.nigrimaculatus.sp.now;刺尾尖盲蜈蚣S.spinicaudus Wood,1862,中国新记录;以及对锈尖盲蜈蚣S.rubiginosus L.Koch,1878的再描述。