Catholics and Muslims for Choice

Water, Air, & Soil Pollution -     

滑坡综合治理方案比选评价模型

为了更好地比选滑坡综合治理方案,针对影响治理方案因素的复杂性和不确定性,以安全可靠性、环境协调性、经济合理性、技术可行性、施工难易、施工工期等做为评价因子,建立了基于熵权决策法的滑坡综合治理方案比选评价模型.根据专家意见建立判断矩阵,利用熵权决策法的原理确定"理想点";通过计算4个设计方案与"理想点"的贴近度与距离来确定方案的排序.结果表明,方案二(锚索抗滑桩与截排水相结合)为最优方案.熵权决策法克服了传统评估方法中主观确定权数的缺陷,保证计算过程和结果的客观性,是一种可行的、定量的滑坡治理方案比选方法.     

Emulation Engines: Choice and Quantification of Uncertainty for Complex Hydrological Models

Complex, mechanistic hydrological models can be computationally expensive, have large numbers of input parameters, and generate multivariate output. Model emulators can be constructed to approximate these complex models with substantial computational savings, making activities such as sensitivity analysis, calibration and uncertainty analysis feasible. Success in the use of an emulator relies on it making accurate and precise predictions of the model output. However, it is often unclear what type of emulation approach will be suitable. We present a comparison of reduced-rank, multivariate emulators built upon different ‘emulation engines’ and apply them to the Australian Water Resource Assessment System model. We examine first-order and second-order approaches which focus on specifying the mean and covariance, respectively. We also introduce a nonparametric approach for quantifying the uncertainty associated with the emulated prediction where this has bounded support. Our results demonstrate that emulation engines based on second-order approaches, such as Gaussian processes, can be computationally burdensome and may be comparable in performance to computationally efficient, first-order methods such as random forests.Supplementary materials accompanying this paper appear online.     

半干旱区的新修梯田作物选择与轮作制度

在半干旱地区,梯田修筑质量一定时,先锋作物的选择及增施化肥是保证新修梯田增产的重要措施。关川河流域的监测资料表明,新修梯田前4年,年平均亩产达到102.02kg,比老梯田增产9.28％,比坡耕地增产67.41％。保证新修梯田增产的主要措施是,以洋芋、春小麦、扁豆、荞麦为先锋作物,实行合理的轮作制度,并根据作物产量需求增施相应数量的化肥。     

机械化农业生产要素优化组合与技术结构选择理论模型

农业机械化的发展,机械化作业项目和机器型号的合理选择,是在生产方式变改、要素优化组合的动态过程中实现的。建立非线性混合整数规划模型,是为了与农业生产投入产出的非线性特征相适应并体现劳动资料(生产工具)技术单位不可分割性原则。通过对苏南地区稻麦生产和华北平原小麦、玉米生产在劳动机会成本和经营(服务)规模均处于变化条件下的生产技术结构进行优化运算和动态考察,具体揭示了生产技术模式转换和机械化发展的经济机理在于要素间相对价格关系的变化,并受到经营服务规模(与社会经济发展、经营主体选择和经济组织发育相关联)的强制约;同时证明“长期费用曲线”为“L”型曲线而非“U”型曲线。     

基材喷附技术的植物选配与建植方式

人为的生产建设尤其是在公路、铁路、矿山、水利、山区住宅等基础项目的建设中形成了不同类型岩石坡面.基材喷附实现岩石坡面生态植被恢复是目前常用的技术形式,为了如期成功实现目标群落的营建,需要对项目区周边气候、土壤、植被等自然环境进行调查,并对坡面地形、坡度、稳定性等特征进行分析.在选择目标群落植物时应满足生态适应性、先锋性、和谐性、抗逆性和自我维持性、生物多样性、持续稳定性等原则,在建植方式上采用播种和栽植相结合,这样才有助于岩石坡面植被的成功恢复.     

Planning iterative investment for landscape restoration: Choice of biodiversity indicator makes a difference

Natural regrowth vegetation offers a cost-effective means of restoring some degraded landscapes. Worldwide, policy responses to climate change are increasing the attractiveness of investment in regrowth protection or facilitation which with strategic planning could also deliver substantial dividends for biodiversity conservation. This study compares the performance of two commonly used indicators of biodiversity conservation priority, irreplaceability and complementarity, as tools to support planning for iterative investment to protect natural regrowth of Brigalow, an endangered ecological community in subtropical eastern Australia. Brigalow covered more than seven million hectares prior to clearing, it now persists ‘intact’ on less than a tenth of that area but there are significant areas of regrowth.Data on Brigalow regrowth derived from mapping and remote sensing identify 10,555 patches covering 280,000 hectares in total. Two different classifications are used to represent Brigalow biodiversity: a land-type classification of 16 ‘regional ecosystems’ mapped at 1:100,000 scale, and a landscape-scale classification of 40 biogeographic subregions that discriminate relatively uniform landscapes at about 1:500,000 scale. Conservation targets are expressed as the extent of regrowth needed to increase the extent of intact or ‘remnant’ areas of each biodiversity feature to either 5% or 10% of its former extent. In each case, irreplaceability and complementarity are positively correlated, and either metric type could be used to identify relatively large sets of high-priority patches. However, regional-scale restoration is likely to involve iterative investment and therefore to require discrimination of relatively small sets of patches of the highest priority for biodiversity conservation. Irreplaceability is not an ideal measure of biodiversity value when planning such iterative processes, simply because irreplaceability is uninformative for ranking ‘high-value’ patches; they all have the highest possible score. This study demonstrates the importance of considering quite fundamental points when choosing metrics for conservation planning, such as the frequency distribution of values they produce. Where planning aims to identify quite small sets of very high value features metrics that are most variable among the highest value patches, like the one used for complementarity in this study, will be more useful than metrics that are strongly bounded at higher values.     

Choice of selectivity coefficients for cation exchange using principal components analysis and bootstrap anova of coefficients of variation

Modellers of the exchange of sodium, potassium, calcium and magnesium in soils have to choose from up to six different equations based on the mass action law paradigm (mainly Gapon, Vanselow, Gaines‐Thomas and Kerr) and up to six different binary cation combinations. In this article a methodology to choose the most appropriate equation and binary cation combinations is presented. The combination of six equations with six binary cation combinations resulted in 36 selectivity coefficients. Each one of these was assessed for 133 calcareous illitic soil samples. Six principal components analyses (PCA) were carried out to find out which three binary cation combinations accounted most for the variance of the soil exchange selectivity. Then a bootstrap anova and multiple comparison (MC) procedure with orthogonal contrasts were carried out to compare the coefficients of variation of the selectivity coefficients calculated with each equation. According to the PCA, the three binary cation combinations involving calcium, and expressed with whichever of the equations of Kerr, Vanselow and Gaines‐Thomas, accounted most efficiently for the variance of the soil exchange selectivity. According to the bootstrap anova and MC analysis, the Gapon equations, either in analytical concentrations or activities of aqueous cations, provide significantly larger coefficients of variation than the equations of Kerr (either in analytical concentrations or activities of aqueous cations), Vanselow and Gaines‐Thomas. The use of the Kerr, Vanselow or Gaines‐Thomas equations and the three binary cation combinations involving calcium resulted in the most effective way of modelling the exchange equilibria of sodium, potassium, calcium and magnesium in calcareous illitic soils.     

Choice of methods for soil microbial community analysis: PLFA maximizes power compared to CLPP and PCR-based approaches

Polyphasic studies that used phospholipid fatty acid analysis (PLFA) in conjunction with community level physiological profiling (CLPP) or PCR-based molecular methods were analyzed in order to evaluate the power of each strategy to detect treatment effects on soil microbial community structure (MCS). We found no studies where CLPP or PCR-based methods differentiated treatments that were not also differentiated by PLFA. In 14 of 32 studies (44%), PLFA differentiated treatments that were not resolved by CLPP analysis. In 5 of 25 studies (20%), PLFA differentiated treatments that were not resolved by PCR-based methods. We discuss PLFA, CLPP, and PCR-based methods with respect to power to discriminate change in MCS versus potential for characterization of underlying population level changes.     

基于选择试验法的北京市城乡居民耕地保护支付意愿研究

[目的]测算北京市城乡居民耕地保护的支付意愿,检验二者的支付意愿差异,并分析差异形成的原因,为制定面向对象差异化的耕地保护政策提供理论借鉴。[方法]采用选择试验法(CE),R统计及部分经济学模型。[结果]农村居民对保护耕地面积、耕地质量和耕地景观生态环境的支付意愿分别为67.24,113.75,51.47元/a,而城镇居民的支付意愿分别为58.07,66.40,150.80元/a。[结论]城镇居民的支付意愿明显高于农村居民,个体支付意愿与其文化程度、家庭年总收入、家庭抚养人口数显著相关;从二者耕地功能需求的角度看,城乡居民对耕地各项功能需求最高的分别为生态功能与生产功能,在需求差异的驱动下样本在选择集中做出符合自己需求偏好的选择。     

基于城市居民特性的温室气体减排支付意愿离散选择研究

基于消费者支付意愿的定量评价是建立我国温室气体减排框架、确定不同地区合理的减排责任和低碳经济发展政策的基础。整个选择过程是系统分量(支付属性)和随机分量(居民特性)共同作用的结果。以2014年成都、重庆、乌鲁木齐3个西部城市收集的意愿性数据为分析基础,借助Logistic离散选择回归模型系统分析影响居民温室气体减排支付意愿的影响因素。结果表明:乌鲁木齐城市居民支付意愿最高,成都次之,重庆最低。所处地域、年龄、受教育程度、年收入、职业、有无子女和支付动机7个变量对支付意愿影响显著。较之与多数完成式数据的研究相比,意愿性调查能更好地通过分析未选择者的约束因素,从而可更好分析居民对温室气体减排的认知和态度。     

3树种抗旱性的综合评价及其抗旱指标的选取

对红柳、侧柏、合头草的9个抗旱指标进行了测定,并运用隶属函数值法对三种树种抗旱性进行综合分析。结果表明,3树种抗旱性大小顺序依次为:红柳>侧柏>合头草。运用灰色关联分析法,对3树种的抗旱性与9个抗旱指标的相关性进行了分析。关联度分析结果表明:叶绿素含量、叶水势、叶片相对含水量以及电导率可作为3树种重要的抗旱评价指标。     

陕西省安塞县生态退耕后农村经济转型及路径选择

基于1980-2007年陕西省安塞县统计数据,分析了生态退耕对农民收入、产业结构、种植结构等的影响,并运用灰色关联度分析法,阐明了安塞县农村产业结构调整的动态变化过程和农业结构调整的方向.探讨了生态退耕后安塞县的农村经济转型问题.结果表明:(1)生态退耕政策的实施显著增加了农民人均收入,促进了农业结构调整和农村剩余劳动力转移.(2)现阶段安塞县农村经济转型的目标在于巩固生态退耕成果,实现农村经济的可持续发展,其根本任务是农业产业结构调整.(3)促进第二产业发展是安塞县农村经济结构调整的重点;种植业、畜牧业、林业是农业内部结构调整的重点.(4)解决农民增收问题和实现农村剩余劳动力稳妥转移是安塞县农村经济转型的关键.     

羊道沟流域侵蚀产沙模型原型选定问题

侵蚀的空间尺度不同,在建立土壤侵蚀模型时,要考虑由于空间变化所引起的侵蚀因子对侵蚀产沙响应的不同。土壤侵蚀模型在空间尺度上可以划分为坡面、小流域和区域三个不同层次。在坡面尺度上,主要考虑坡面侵蚀的垂直分带性及其相互影响;小流域尺度上,不但考虑坡面侵蚀的特点,还要考虑坡面来水来沙对沟道侵蚀产沙的影响、重力侵蚀及泥沙输移情况;在区域尺度上则主要考虑小流域各自的侵蚀产沙特点及其相互影响。通过分析国内外常用的不同尺度上的侵蚀产沙模型及其最新发展情况,并借鉴羊道沟流域研究的丰富经验,提出了羊道沟流域作为王家沟流域-侵蚀产沙单元的侵蚀产沙概念模型,为流域侵蚀产沙模型尺度之间转换提供借鉴。     

Choice of nitrogen fertilizer affects grain yield and agronomic nitrogen use efficiency of wheat cultivars

Abstract

Nitrogen use efficiency (NUE) is low in cereals especially in wheat. Different wheat cultivars may vary in NUE due to inherited biological nitrification inhibition (BNI) potential. In this study, three wheat cultivars (Punjab-2011, ARRI-2011 and Millat-2011) were fertilized at the rate of 140?kg ha^?1 with three N sources [nitrophos (NP), urea and calcium ammonium nitrate (CAN)]. The soil nitrate (NO₃^?)-N contents were significantly enhanced coupled with simultaneous decrease in ammonium (NH₄⁺)-N contents in the rhizosphere of cultivar Punjab-2011, fertilized with NP; however, cultivar Millat-2011 receiving urea behaved in contrast. Wheat cultivar Punjab-2011 fertilized with NP had the highest grain yield and agronomic NUE than other treatments due to significant increase in chlorophyl contents, allometric and yield parameters. The highest net benefit was recorded from the cultivar Punjab-2011 fertilized with CAN. In conclusion, use of NP in Punjab-2011 enhanced the grain yield and agronomic NUE.     

基于GIS的中国潜在水土流失评价指标研究

综合分析了影响水土流失的各主要因子 ,如地表形态 (地貌 )、地面物质 (土壤及其母质 )、动力条件(降雨、径流、风力和冻融作用 )、人为活动影响 ;结合现有的水土保持数据和研究成果 ,确定以土壤抗冲性、降雨侵蚀力、地形起伏度等作为基于GIS的中国潜在水土流失评价的指标 ,用以进行全国水土流失宏观分析评价。     

水土综合整治是秦巴山区防洪减灾和改善生存环境的必然选择

 为了防灾减灾,改善陕南秦巴山区群众的生存环境,对该区基本情况及洪灾发生情况作了介绍,对灾害原因进行了分析。认为造成川道水毁的原因,既有自然因素,也有人为因素,其中人为因素包括改河造田,缩小河道断面,没有为洪水留足出路,上游水土保持防治工作滞后和沟道河流疏浚跟不上等。今后,秦巴山区防洪减灾、改善生存环境的对策是:妥善处理好人与自然的关系,变与洪水争地为给洪水以出路,统筹兼顾山上与山下的关系,加强上游水土流失综合整治 ,搞好水土保持预防监督和河道疏浚清障等。     

A Comparison of Focus Group Interviews to In-Depth Interviews in Determining Food Choice Influences

ABSTRACT

Two common methods of collecting qualitative data are the in-depth interview and the focus group. This study compared the two interview methods on four criteria: (1) number of unique factors generated, (2) time requirements, (3) relative cost, and (4) ease of data collection. Both interview methods discussed the topic “What factors influence your food choices.” Participants were 18 to 24 year old Anglo and Hispanic college women. Eight focus groups and twenty-eight in-depth interviews were completed. Focus groups required approximately half the time, cost half as much and yielded more factors. Focus groups were more difficult to schedule but easier to conduct.     

Effects of Experimental Plant Density Reductions on Plant Choice and Foraging Behaviour of Bees (Hymenoptera:Apoidea)

This investigation tested how a reduction in plant density affected the willingness of bees to visit a number of palaearctic plant species. Pairwise comparisons were made between the first bee visits to control and manipulated plots. The results showed that bees still chose and utilized plant species with a small number of open flowers in the density-reduced plots. In plant species with a larger number of flowers, bees often chose the dense plots or did not visit as many flowers on plants in the density-reduced plots. Multiflowered plants may produce only small amounts of nectar in order to discourage pollinators from foraging too long in the inflorescences. This would result in a decrease in the number of self-pollination events and an increase in pollen export.     

论地质条件对某水电站坝型选择的影响

某水电站的地质条件比较复杂,在前期地质工作不足的条件下,认为在此处的工程地质条件总体较优,混凝土拱坝和心墙堆石坝都比较适合;随着坝址区地质勘测的深入,在分析研究了重力坝与拱坝方案存在的主要工程地质问题后,进而比较了上述坝型地质条件的各自利弊,最后推荐了心墙堆石坝.