Water markets and soil salinity nexus: Can minimum irrigation intensities address the issue?

Agricultural water markets can facilitate adjustments to water scarcity and competition and enhance economic efficiency, but markets cannot automatically balance efficiency, equity and environmental sustainability goals. The consequences of water trading on soil salinity in irrigation areas are not yet fully understood, but recognized as an issue that needs to be analysed. This paper explores the nexus between water trading and groundwater-induced soil salinity in a selected irrigated area in the Murray-Darling Basin. Results show that minimum irrigation intensities must be met to flush salts out of the root zone especially in shallow water table/high salinity impact areas. Such minimum irrigation intensities are helpful but not necessarily in deep water table/low salinity impact areas. Should water markets lead to permanent water transfers out of mature irrigation areas, minimum irrigation intensity needs might not be met in high salinity impact areas, causing substantial negative impacts on resource quality and agricultural productivity. Water trading that adds to salinity cannot be economically viable in the long run. The tradeoffs between water trading and environmental and equity goals need to be determined. This work contributes to the wider debate on Australian water policy aimed at achieving water security through water trading in the Murray-Darling Basin.     

Inheritance of morphological traits of periwinkle mutants with modified contents and yields of leaf and root alkaloids

Periwinkle Catharanthus roseus is a medicinally important plant producing anticancer and antihypertension alkaloids. Two mutants, one dwarf and one semidwarf and both, with a high alkaloid content in the roots and one mutant with a wavy leaf margin and a high alkaloid content in its leaves were obtained after induced chemical mutagenesis with ethyl methane sulphonate and N-nitroso-N-ethylurea in the variety ‘Nirmal’, which is resistant to dieback disease. These mutants were evaluated in the M₃ and M₄ generations. The dwarf and semidwarf mutants differed from the parental variety for many morphological characters, while the mutant with the wavy leaf margin differed mainly in leaf size and leaf thickness. Although both dwarf and semidwarf mutants showed a significantly higher alkaloid content in their roots in both generations, only the semidwarf mutant gave a significantly higher (23%) root alkaloid yield than the parental variety. The mutant with the wavy leaf margin showed a significantly higher alkaloid content in the leaves in both the M₃ and M₄ generations and also had a significantly higher (21%) leaf alkaloid yield than the parental variety. All three mutants were found to be controlled by monogenic recessive genes; the genes for ‘dwarfness’ and ‘semidwarfness’ were allelic to each other, with the allele for semidwarfness being dominant over the allele for dwarfness. The gene for the wavy leaf margin was inherited independently of the genes for dwarfness and semidwarfness.     

振动钻削中切屑颗粒的运动规律

对单个切屑颗粒在水平排屑管中的运动规律进行了较为全面的分析,建立了切屑颗粒的水平排屑管中的轴向和径向运动方程,得出了单个切屑颗粒在无轴向振动和有轴向振动条件下的不同运动规律。研究结果表明,利用轴向振动使常规钻削加工中常出现的切屑堵塞现象,可以通过有效地破坏近壁流动死区而得到控制,与常规钻削加工相比,振动钻削提高了系统的排削提高了系统的排屑能力。     

果菜类蔬菜公路冷藏运输模拟试验研究

由于运输过程中,震动引起的机械损伤会导致蔬菜后期运输和贮藏的困难。通过对胡萝卜、黄瓜、番茄、甜椒这4种果菜类蔬菜公路冷藏运输的模拟试验研究,分析温度、湿度和振动对蔬菜运输和品质带来的影响。     

高速公路边坡滑动失稳机理分析与加固研究

分析了内蒙古呼和浩特——老爷庙高速公路K453 200~K453 800段的滑动失稳破坏,该段以路堑形式通过,在雨季后期,岩土体突然发生滑动失稳变形,通过对边坡岩土体物理、力学性能的试验研究,得到了产生边坡失稳的主要原因是:边坡下部存在泥岩夹层,该泥岩遇水膨胀,随着含水量的增加残余强度明显衰减为20.8%,当坡体较大范围内土层强度衰减至残余强度时坡体必然发生滑动失稳而破坏。采用了抗滑桩和预应力钢筋砼框架结构等加固措施,收到了较好的效果。     

DISTAL PHALANX FRACTURES IN HORSES

The case records of 274 horses with fractures of the distal phalanx were reviewed. Fifty-two horses had bilateral forelimb fractures, for a total of 326 distal phalanx fractures. The fractures were classified into one of five previously described types, based on the radiographic anatomic configuration of the fracture. Solar margin fractures, which have been briefly described in other reports and previously classified as type V fractures, were identified in 132 horses. This type of fracture is distinct from other distal phalanx fractures. Due to the high incidence of solar margin fractures, these fractures were classified as a separate type (type VI). Follow-up radiographic examinations to assess fracture healing were available for 36 horses. Twenty-two horses with distal phalanx fractures (three type I, nine type II, two type III, one type IV, one type V, and six type VI) had radiographic evidence of complete bony union of the fracture at a mean of 11 months after injury. Eight horses with complete type II fractures involving the articular surface had bony union of the body and solar margin, but not the subchondral bone at the articular surface, a mean of 11 months after injury. Six horses (four type II and two type IV) had little radiographic evidence of bony healing during the follow-up period. All fractures that eventually healed had evidence of progression toward bony union by 6 months after injury.     

受迫振动时木材阻尼参数的研究

本文在振动理论及测试技术的指导下,用共振法测得了木材试样频率响应函数的幅频特性曲线,并用半功率点法求出了受迫振动下木材的阻尼参数。     

凤凰卫视新闻策略的战略处境和策略选择

凤凰卫视新闻竞争力的核心是具有中国本土明确的地缘优势,地处本土和两岸三地地缘交汇处,先天拥有大中华区信息集散和流通的优先话语权,利于在本土公众中形成某种中立性的立场暗示,对中国本土展开和而不同的媒介策略。同时,凤凰卫视新闻战略遭遇的现实挑战是:立足于本土区位边缘,人文语境、政治趋向同本土空气极有可能形成某种隐性疏离甚至是话语对立的倾向;在新闻评论话语方面面临和本土电视新闻同质化的危险;随着中国本土电视新闻话语空间和电视新闻形态的发展以及两岸三地进一步凝聚,凤凰卫视既在中国本土地区面临本土卫视群雄竞起的挑战     

土壤及叶面调控对核桃“叶缘焦枯病”的防控效果

[目的]为新疆核桃叶缘焦枯生理病害的防控提供依据.[方法]通过对叶面喷施生理调控剂、土壤调控、叶面喷生理调控剂+土壤调控、对照等4个处理的防控效果试验,研究不同防控处理对核桃病害发生程度、核桃商品性、叶片矿质元素含量和元素比例的影响.[结果]各防控处理对降低核桃病害发生程度、提高核桃商品性、减少叶片中离子失衡,具有显著效果.叶面喷生理调节剂+土壤调控处理的效果最好,可使叶片Na+含量降低18.8;、Ca2含量提高7.4;、Cl含量降低16.3;、Na/K比降低36.0;、Na/Ca比降低24.2;、Cl/N比降低19.4;;与对照相比,增产36.8;,黑缩果率减少70.1;,商品率提高36.4;,增加经济效益1 456元/667m2.叶面喷生理调节剂+土壤调控处理的防效为89.9;,叶面喷生理调节剂的防效为80.1;,土壤调控的防效为63.2;.[结论]叶面喷生理调节剂和土壤调控各处理可有效降低病叶发生率,减少焦枯病斑面积占比,降低病情指数;可显著提高核桃单产,减少黑缩果率,提高商品率;减少Na+和Cl向叶片富集,防止核桃叶片中矿质元素比例失衡,减轻“叶缘焦枯病”症状及危害.     

草莓温室施用百菌清对施药及采收人员的暴露水平与风险评估

采用手动背负式喷雾器,在草莓温室中均匀施用75%百菌清可湿性粉剂,通过贴片法分析了施药者及果实采收者的人体暴露量,研究了草莓温室施用百菌清对操作人员的职业暴露风险。结果表明:在草莓温室中施用百菌清,对施药者人体暴露的施药液量为19.2~46.6 mL/h,平均为30.2 mL/h,主要暴露部位为小腿;采收果实时,施药后第1天采收者人体暴露的施药液量为3.8 mL/h,第7天时为0.027 mL/h,主要暴露部位均为手部。在本研究暴露条件下,施药者的安全限值(MOS)为0.258,表明该暴露环境对施药者存在风险;施药后1~7 d,采收者的MOS值均1,表明该暴露环境对采收者人体暴露为安全。研究表明,在草莓温室中施用百菌清,对田间操作人员存在职业暴露风险,因此应注意加强防护措施,或缩短暴露时间;采收时,对采收者无职业暴露风险,但应对主要暴露部位手部加强防护。