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What determines irrigation efficiency when farmers face extreme weather events? A field survey of the major wheat producing regions in China

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Journal of Integrative Agriculture 2018年第8期17卷 1888-1899页

作者： SONG Chun-xiao les Oxley MA Heng-yun College of Economics and Management Henan Agricultural University Department of Economics and Finance University of Waikato

Water availability is a major constraint on grain production in China, therefore, improving irrigation efficiency is particularly important when agriculture faces extreme weather events. This paper first calculates irrigation efficiency with a translog stochastic frontier production function and then investigates what happens when extreme weather events occur via a Tobit model. The estimated results reveal several important features of irrigation practices: i) irrigation efficiency is lower when extreme weather events occur; ii) large variations in irrigation efficiency occur across irrigation facilities; iii) the farm plots exhibit an extreme distribution across efficiency levels; and iv) water-saving techniques, technology adoption, and the maintenance of farmers’ economic resilience are major determinants of irrigation efficiency. Based on these results we propose the following recommendations: i) farmers should balance crop yield and water use; undertake relevant training programs and adopt water-saving techniques; ii) local governments and researchers should help farmers to find the optimal level of irrigation water use based on their own circumstances and provide better water-saving techniques and training programs rather than simply encouraging farmers to invest in irrigation facilities in the most extreme weather years; and iii) the income level of farm households should be increased so as to improve their resilience to natural disasters.

关键词： irrigation efficiency determinants irrigation facilities water-saving techniques extreme weather events

Effects of excluding bottom-disturbing mobile fishing gear on abundance and biomass of groundfishes in the Stellwagen Bank National Marine Sanctuary,USA

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Current Zoology 2010年第1期56卷 134-143页

作者： Briana K.BROWN Elizabeth SOULE les KAUFMAN Biology Department Boston University

The Stellwagen Bank National Marine Sanctuary （southern Gulf of Maine, northwest Atlantic） is partially overlapped by the Western Gulf of Maine Closure Area （WGMCA）. This is a region in which mobile, bottom-disturbing fishing gear has been banned by the New England Fishery Management Council to facilitate the rebuilding of depleted gronndfish populations. We assessed the effects and effectiveness of the WGMCA on groundfish assemblages using habitat-stratified （gravel, sand, mixed benthic habitats） sampling by means of a commercial trawler, inside and outside of the WGMCA. Sampling occurred over three mouth-long sampling periods in 2004-2005, two during the spring seasons and one during the fall season. A total of 18 species were analyzed for protection effects. After controlling for substratum, location and sampling season, eight groundfish species exhibited higher mean proportional abundance inside than outside the WGMCA while two were proportionally more abundant on average outside of the closure. Four species had higher mean proportional biomasses on average inside the closure and three outside. We conclude that the WGMCA may be achieving its goal of rebuilding abundance and biomass for some commercially targeted groundfishes but not all. This study, six to seven years post-closure establishment, reveals fine-scale spatial and taxonomic complexity which will require a very different monitoring protocol than the one currently in place if adaptive management is to be successful in the region [Current Zoology 56 （1）： 134-143, 2010].

关键词： Effects of fishing Groundfish Gulf of Maine Stellwagen Bank National Marine Sanctuary Trawl closure

Diversity amid globalization : world regions, environment, development / les Rowntree ... [et al.]. 2nd ed

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Mechanical properties of cotton fabric reinforced geopolymer composites at 200-1000℃

2003年

作者： les Rowntree ... [et al.].

Includes bibliIncludes bibliographical references and index.

ISBN: (纸本)0130932914

Includes bibliIncludes bibliographical references and index.

关键词： Geography.

来源：畅想之星图书光盘版（南... 畅想之星图书光盘版（南... 评论

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Journal of Advanced Ceramics 2014年第3期3卷 184-193页

作者： Thamer ALOMAYRI les VICKERS Faiz U.A.SHAIKH It-Meng LOW Department of Imaging&Applied Physics Curtin UniversityGPO Box U1987PerthWA 6845Australia Department of Physics Umm Al-Qura UniversityMakkah 21955Saudi Arabia Department of Civil Engineering Curtin UniversityGPO Box U1987PerthWA 6845Australia

Geopolymer composites containing woven cotton fabric(0-8.3 wt%)were fabricated using the hand lay-up technique,and were exposed to elevated temperatures of 200℃,400℃,600℃,800℃and 1000℃.With an increase in temperature,the geopolymer composites exhibited a reduction in compressive strength,flexural strength and fracture *** heated above 600℃,the composites exhibited a significant reduction in mechanical *** also exhibited brittle behavior due to severe degradation of cotton fibres and the creation of additional porosity in the *** images verified the existence of voids and small channels in the composites due to fibre degradation.

关键词： geopolymer composites microstructures mechanical properties fracture toughness

Alarm cue induces an antipredator morphological defense in juvenile Nicaragua cichlids Hypsophrys nicaraguensis

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Current Zoology 2010年第1期56卷 36-42页

作者： Maria E.ABATE Andrew G. ENG les KAUFMAN Department of Biology Boston University Department of Neurosurgery University of Pennsylvania

Olfactory cues that indicate predation risk elicit a number of defensive behaviors in fishes, but whether they are sufficient to also induce morphological defenses has received little attention. Cichlids are characterized by a high level of morphological plasticity during development, and the few species that have been tested do exhibit defensive behaviors when exposed to alarm cues released from the damaged skin of conspecifics. We utilized young juvenile Nicaragua cichlids Hypsophrys nicaraguensis to test if the perception of predation risk from alarm cue （conspecific skin extract） alone induces an increased relative body depth which is a defense against gape-limited predators. After two weeks of exposure, siblings that were exposed to conspecific alarm cue increased their relative body depth nearly double the amount of those exposed to distilled water （control） and zebrafish Danio rerio alarm cue. We repeated our measurements over the last two weeks （12 and 14） of cue exposure when the fish were late-stage juveniles to test if the rate of increase was sustained; there were no differences in final dimensions between the three treatments. Our results show that 1） the Nicaragua cichlid has an innate response to conspecific alarm cue which is not a generalized response to an injured fish, and 2） this innate recognition ultimately results in developing a deeper body at a stage of the life history where predation risk is high [Current Zoology 56 （1）： 36-42, 2010].

关键词： Alarm substance Inducible defense Phenotypic plasticity Cichlid Chemical cue Antipredator

Do farmers care about climate change? Evidence from five major grain producing areas of China

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Journal of Integrative Agriculture 2019年第6期18卷 1402-1414页

作者： SONG Chun-xiao LIU Rui-feng les Oxley MA Heng-yun College of Economics and Management Henan Agricultural UniversityZhengzhou 450002P.R.China Department of Economics and Finance University of WaikatoHamilton 3240New Zealand

Using a logistic model,this paper empirically investigated farmers’perception of climate change and its determinants based on a field survey of 1 350 rural households across five major grain producing provinces in *** results show:i)There is an apparent difference in perception levels for long-term temperature and precipitation ***,57.4%of farmers perceived the long-term temperature change correctly,but only 29.7%of farmers perceived the long-term precipitation change correctly;ii)The factors influencing the farmers’perceptions are almost completely different between precipitation and temperature,the former are mostly agriculture related,while latter are mostly non-agriculture related,except for farm size;and iii)Farmers are not expected to pay more attention to long-term precipitation changes over the crop growing seasons,because less than 30%of farmers can correctly perceive long-term precipitation ***,to improve the accuracy of farmers’perceptions of climate change,the government is recommended to:i)enhance education and training programs;ii)speed up land transfer and expand household land farm size;iii)develop farmer cooperative organizations;iv)invest more in agricultural infrastructure,specifically in major grain producing regions;and v)improve the agricultural environment and increase farming income.

关键词： China major grain producing areas determinants climate change perception irrigation areas

Physical investigation on the behaviours of voussoir beams

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第3期12卷 516-527页

作者： Chaoshi Hu Derek Apel les Jozef Sudak Wei Victor Liu Zhaoyuan Chu School of Mining and Petroleum Engineering Department of Civil and Environmental EngineeringUniversity of AlbertaEdmontonT6G 1H9Canada Department of Mechanical and Manufacturing Engineering University of CalgaryCalgaryT2N 1N4Canada Anhui Yitong Construction Consulting and Management Ltd.YuexiAnqing246000China

It is important to understand the behaviour of voussoir beams in the design of underground *** are a large number of discrepancies between the re sults obtained by differe nt researchers so *** resolve these discrepancies,physically testing the stress distribution at the mid span and abutment of voussoir beam is the *** this paper,a simple two-block voussoir beam was built with loading *** displacement and strain of the voussoir beam were measured by a digital image correlation *** strain distribution along the joints of voussoir beams was firstly ***,the relationship between transverse load and midspan displacement of voussoir beam was *** is found that the stress distributions at the midspan and abutment are different both in shape and *** stress distribution is changing as the loading changes as well.

关键词： Voussoir beam Stress distribution Image correlation

Tangent and Normal Cones to Real Surfaces

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Chinese Quarterly Journal of Mathematics 1995年第4期10卷 62-71页

作者： Donal O‘’SHEA les Mathematics Department Mount Holyoke

Unlike the complex case, the natural algebraic and geometric definitions of tangentand conormal cones at singular points of real surfaces do not coincide. Nonetheless, these conesprovide valuable information about the... 详细信息

关键词：实曲面法锥面切线锥面

Management factors affecting densities of common grassland birds of high elevation grasslands of eastern South Africa:Ingula as a case study

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Chinese Birds 2017年第1期8卷 37-49页

作者： David H.Maphisa Hanneline Smit-Robinson les G.Underhill Res Altwegg South African National Biodiversity Institute Statistics in Ecology Environment and ConservationDepartment of Statistical SciencesUniversity of Cape Town Bird Life South Africa Applied Behavioural Ecological and Ecosystem Research Unit(ABEERU) UNISA Animal Demography Unit Department of Biological SciencesUniversity of Cape Town African Climate and Development Initiative University of Cape Town

Background: World?wide grassland birds are in decline due to habitat loss and degradation resulting from inten?sive agricultural practices. Understanding how key grassland habitat attributes determine grassland bird densities is required to make appropriate conservation decisions. We examine drivers of bird densities in a South African grass?land area that has been managed for biodiversity conservation with reduced grazing ***: We estimated the density of the eight most common grassland bird species encountered in our area to evaluate the effects of recent grassland management changes on the avifauna. We collected data on birds and habitat from the austral summers of 2006/2007, 2007/2008 and 2010/2011. We used hierarchical distance sampling methods to estimate density of birds relative to two main habitat variables, i.e., grass cover and height. In addition, we used regression splines within these distance sampling models as a more flexible description of suitable ranges of grass height and cover for each ***: For most species, density is related to grass height and cover as expected. The African Quailfinch(Ortygospiza atricollis) and Common Quail(Coturnix coturnix) preferred relatively short and open grass. The Yellow?breasted Pipit(Anthus chloris), African Pipit(Anthus cinnamomeus) and Red?capped Lark(Calandrella cinerea) preferred short and relatively dense grass, while the Wing?snapping Cisticola(Cisticola ayresii) preferred grass of intermediate height and cover. The Cape Longclaw(Macronyx capensis) and Zitting Cisticola(Cisticola juncidis) preferred tall and dense grass. Our results agree with previous studies that grass height combined with grass cover are the most important habitat features that managers should manipulate in order to increase the density of target species. The regression splines show that the effect of these two habitat variables on density is well described by linear relationships for most ***: This

关键词： Density and detection Grassland birds Grass height and cover Hierarchical distance sampling models