Successful outcome after surgical correction of large colon atresia in a colt foal

This report describes successful surgical correction and long-term survival of a case of large colon atresia in a 24-h-old Warmblood colt, referred with signs of unrelenting abdominal pain and a suspicion of meconium impaction. Radiographic and ultrasonographic examination was indicative of large colon meconium impaction with secondary ileus. Due to deterioration of the foal, surgery was recommended. An atretic segment was found between the left ventral and dorsal large (ascending) colon. A band of fibrous tissue with no identifiable lumen connected the segments. Surgical correction was done by performing a stapled side-to-side anastomosis. Twelve days after surgery, the foal was discharged. Twenty-two months after discharge, the owner reported the foal developing as expected compared with its peers, but had a mild, self-limiting episode of colic at 20 months of age.     

从星球化到在地性：基于克莱因四元群模型的风景园林思潮研究计划

随着人类观察世界的能力大幅提升,设计与研究的尺度得到了极大拓展,星球化(planetarization)与在地性(locality)同时成为空间设计学科重点关注的议题,近年来涌现出多个新思潮。基于克莱因四元群模型构建的风景园林思潮研究计划旨在建立一套理论框架以对不同研究实践进行更系统的讨论分析,为国内风景园林学科与行业带来新的思考,并运用新理论框架重点介绍了4个风景园林思潮,包括星球城市化背景下的风景园林理论、新地理视角中的空间叙事、关注本土议题的风景园林研究以及直觉导向的在地探索。     

纵横刀组协同式马铃薯种薯切块装置设计与试验

针对马铃薯种薯切块机械化程度低的问题,设计了一种纵横刀组协同式马铃薯种薯切块装置,对其关键部件进行设计,通过对马铃薯种薯切割过程的力学分析、运动学分析和能量学分析,建立了切种能量的数学模型,确定了影响马铃薯切种效果的主要因素。以切种效率、切种合格率为评价指标,以圆盘刀半径、输送辊与圆盘刀垂直中心距、圆盘刀轴转速和夹持辊轴转速为试验因素,进行了四因素四水平正交试验。对正交试验结果进行方差和极差分析,结果表明:当圆盘刀半径为180 mm、输送辊与圆盘刀垂直中心距为190 mm、圆盘刀轴转速为115 r/min、夹持辊轴转速为56 r/min时,切种效率为74.5 kg/min,切种合格率为98.8%,满足马铃薯切种作业要求。     

Efficacy of N2O2 donor schiff bases and their Zn2+ complexes on various morphological and biochemical parameters of Cicer arietinum L.

Schiff-base polydentate ligands types of salen and salophen can form stable complexes with Zn²⁺ and these metal complexes can act as a source of zinc (Zn) to plant's body if they are used as micronutrient supplements. Inspired by these facts, four different Schiff-base ligands and their Zn²⁺ complexes were first synthesized and then characterized by different analytical and spectroscopic techniques. To investigate their effects local chickpea seeds were treated with each ligands and complexes and different morphological and biochemical parameters were monitored. Among all the complexes and ligands it was found that the C4 complex, that is, [N,N'-(o-phenylene)bis-(3-methoxysalicylidenediamine)] monohydrate showed the maximum efficacy when treated as a micronutrient supplement for Cicer arietinum L. So that these complexes especially the C4 can act as an potential source of Zn.     

An approach to determining forest areas with recreational potential: The case of forest areas around main transportation roads in the Maçka Region of Trabzon,Turkey

It is most important to determine areas with recreation potential that can permit sustainable use of forest resources and also meet recreational uses. Under the method described in this study, using the Geographic Information System (GIS), a spatial suitability model for recreational use was combined with a recreational priority perceptual suitability model that depends on principal component analysis (PCA) and is based on the perceptions of both recreational users and experts. Using principal component analysis, five priority components explaining 69.371% of the total variance were identified out of 12 perceptual suitability components. These components are scenic beauty, accessibility, the surface of the landscape, tree type, and forest stand condition. The recreation terrain suitability value of an area with recreational potential was assessed with the assistance of these five priority components. This enabled us to generate a recreation terrain suitability value equation and a recreation terrain suitability value scale for a potential recreation area. This applicability of this approach was demonstrated in the identification of potential recreation areas in Trabzon, Turkey.     

不同原料生物炭对铵态氮的吸附性能研究

为探讨不同原料生物炭对铵态氮吸附量及吸附机制,以花生壳、玉米秆、杨木屑和竹屑为原料,在500℃下充N_2保护热解制备生物炭,通过电镜扫面图(SEM)与傅立叶红外光谱图(FTIR)表征NH_4~+-N在生物炭表面的吸附特征,结合批量平衡吸附试验,对比研究不同原料生物炭对NH_4~+-N的吸附性能。结果表明:吸附后生物炭表面附着颗粒或粉末物质,孔隙被填充,表面变得较为平坦。四种生物炭表面分布的-OH、-C=O、-C-O,以及花生壳生物炭与玉米秆生物炭表面的-CH_3、-CH_2、-O-参与了吸附;Langmuir方程可以较好地拟合四种生物炭对NH_4~+-N的等温吸附;吸附均在50 min内达到平衡,伪二级动力学方程均可以较好地描述生物炭对NH_4~+-N的动力学吸附过程;在溶液pH=7.00条件下,初始浓度为800 mg·L~(-1)的体系中,四种生物炭对NH_4~+-N的最大吸附量为9.5~15 mg·g~(-1),吸附能力大小为花生壳生物炭玉米秆生物炭竹屑生物炭杨木屑生物炭。研究表明,生物炭表面含氧官能团对吸附NH_4~+-N起到决定性作用,吸附为单分子层吸附,且由快速反应所控制,四种生物炭中吸附性最好的是花生壳生物炭。     

家畜环境卫生学课程线上教学模式的研究

随着互联网信息技术发展和智能手机的普及,顺应时代发展的需要,线上教学成为未来高校教学活动开展一种必然途径。本文基于学习通和QQ群课堂平台构建了家畜环境卫生学课程的教学设计方案,并详细介绍了教学活动的实施办法,分析了线上教学面临的困难,并提出了相应对策,以期为高等学校线上教学改革提供参考。     

北京昌平区农业景观野生蜂多样性的时空动态分布

近年来,由于生境质量的下降和生境丧失,野生蜂多样性急剧下降,严重威胁传粉服务和农业的可持续发展。为揭示野生蜂在农业景观镶嵌体中的时空分布格局及不同生境对野生蜂保护的重要性,本研究于2016年4—9月采用网捕法调查了北京昌平农业景观4种主要生境类型(人工林、自然灌木林、荒草地和桃园)中的野生蜂,分析不同生境类型中野生蜂多样性及其时间动态变化特征。结果表明:野生蜂及其中的大体长蜂和独居蜂的物种数和个体数,以及中体长蜂的个体数均在自然灌木林中最高,人工林中小体长蜂个体数最多,野生蜂总个体数和总物种数均在桃园中最低。在不同月份,所有功能群野生蜂均在自然或半自然生境中最高,5月桃园中最低,原因可能与桃园中对地表杂草的集约化管理有关。多度最大的4个优势物种依次为黄胸彩带蜂、铜色隧蜂、黄芦蜂和隧淡脉隧蜂,其在生境间的时间动态特征不同。调查的4种生境均为野生蜂提供了可利用资源,但自然生境和半自然生境的作用更大;其中,自然灌木林维持了较多具有较高潜在传粉效率的中体长和大体长野生蜂,具有更高的保护价值。为了促进该地区农业景观中不同功能群野生蜂多样性及传粉服务,需提高生境类型的多样性,同时在野生蜂活动高峰季节采取低集约化的生境管理方式。     

基于SNP芯片揭示中国玉米育种种质的遗传多样性与群体遗传结构

【目的】选择具有重要育种价值的玉米自交系进行遗传多样性与群体遗传结构解析,为玉米育种实践提供指导和参考。【方法】选用344份具有广泛代表性和时效性的玉米自交系,其中包括美国主要杂种优势群、由国内地方种质发展来的杂种优势群、由美国商业化杂交种选系发展来的杂种优势群以及近年来在中国玉米育种中应用的新种质。利用北京市农林科学院玉米研究中心自主研发的包含3 072个SNP位点的Maize SNP3072芯片对供试自交系进行全基因组扫描,揭示其遗传多样性与群体遗传结构。【结果】在344份自交系中,3 072个SNP标记所检测到的基因多样性为0.028—0.646,平均为0.442;多态信息含量(PIC)为0.028—0.570,平均PIC值为0.344。群体遗传结构分析表明,K=8时,△K值最大,即本研究所采用的自交系群体可以划分为8个类群,分别为旅大红骨群、黄改群(又称塘四平头群)、Iodent群、兰卡斯特群、P群、改良瑞德群、瑞德群和X群,其中前7个群已有报道且基本被育种家所公认,第8个群为近年来以X1132X等杂交种作为基础材料选育出的优新种质,命名为X群。比较8个类群,遗传分化系数(Fst)为0.319—0.512,遗传距离为0.229—0.514。AMOVA结果表明类群间存在显著的遗传变异,占总遗传变异的38.6%,类群内的遗传变异占58.1%。PCA(主成分分析)结果显示,X群与黄改群、兰卡斯特群遗传关系较远,与Iodent群遗传关系较近。各类群平均基因多样性分析结果表明,随着类群改良年代的增加,类群平均基因多样性降低,其中X群种质平均基因多样性最高;进一步分析表明,美国种质类群(兰卡斯特群、瑞德群和Iodent群)和国内地方种质改良系(旅大红骨群和黄改群)核心材料多样性下降幅度较大,P群和改良瑞德群核心材料下降幅度较小,X群核心材料则没有下降趋势,说明X群核心材料仍然保留了较高的遗传多样性,未来还有很大的育种潜力可挖掘。【结论】近年来,以X1132X等杂交种所构建的基础材料选育而成的京724等系列优良自交系,区别于其他已知的7大类群,可以单独成群,称之为X群。该群与黄改群之间存在较远的遗传距离,从分子水平验证了"X群×黄改群"这种强杂优模式具有良好的应用潜力。