Evaluation of Dynamic Structural Disorders in the Upper Airways and Applied Rein Tension in Healthy Dressage Horses During Riding in Different Gaits and Head–Neck Positions

Flexion of the horse’s head and neck during dressage riding reduces the pharyngeal lumen with the risk of increased upper airway resistance and upper airway obstructions. According to the Fédération Equestre Internationale, hyperflexion is achieved through force, whereas the position low–deep–round is nonforced. The objectives of this study were to evaluate (1) applied rein tension and (2) dynamic structural disorders in the upper airways in dressage horses in different gaits and different head–neck positions (HNPs). Overground endoscopy (OGE) and rein tension were evaluated in 13 clinically healthy and high-performance Warmblood dressage horses while being ridden in a standardized program comprised of four different gaits (halt, walk, trot, and canter) and in four HNPs (unrestrained, competition frame, hyperflexion, and low–deep–round). All included horses were able to achieve the desired HNPs. The HNP low–deep–round showed significantly lower rein tension than competition frame (P < .001) and hyperflexion (P < .001). An association was found between dynamic structural disorders in the upper airway tract evaluated by OGE and head–neck flexion, but this association was not linked to the degree of flexion. The HNP hyperflexion was neither associated with greater rein tension nor severe dynamic structural disorders than the HNP competition frame. This study confirms that low–deep–round is a nonforced position, in contrast to hyperflexion. Further studies are needed to evaluate whether dynamic structural disorders are a result of flexion or if the degree of flexion has an impact.     

麦/油-稻轮作下秸秆还田与氮肥管理对直播杂交稻氮素利用特征的影响

【目的】探明秸秆还田和氮肥管理对麦/油后直播杂交稻氮素积累、转运、氮肥利用效率及籽粒产量的影响。【方法】选用优质三系杂交稻宜香优2115,采用二因素裂区设计,麦、油茬田同步开展试验,处理完全一致。主区为麦/油秸秆全量翻埋还田(M₁)和秸秆不还田(对照,M₀),副区设4个氮肥管理,即不施氮对照(N₀)、m_基肥∶m_分蘖肥∶m_促花肥∶m_保花肥比例分别为1∶0∶0∶0(N₁)、3∶3∶2∶2(N₂)、2∶2∶3∶3(N₃),测定了直播杂交稻主要生育时期各器官的氮素积累量及籽粒产量。【结果】结果表明,两种轮作方式下,氮肥管理对直播杂交稻主要生育时期的氮素积累、齐穗后茎鞘、叶片的氮素转运及稻株氮素利用效率均存在显著或极显著的调控效应。秸秆还田显著提高麦/油茬杂交稻中后期的氮素积累量、茎鞘和叶片的氮素转运量以及氮肥利用效率,其中,氮肥农学利用率、氮肥偏生产力和氮肥表观利用率较秸秆不还田分别提高了34.96%/28.76%、2.52%/2.61%和31.91%/22.30%。同时,油菜秸秆还田下直播杂交稻各生育时期氮素积累和产量较麦秆还田表现更好,籽粒产量提高481 kg/hm²(5.22%)。M₁N₂处理、M₀N₃处理下,直播杂交稻各阶段的氮素积累速率明显加大,促进结实期茎鞘和叶片的氮素向穗部转运,成熟期稻株氮素积累量优势明显且有较高的氮素利用效率(麦/油茬稻氮肥农学利用率、偏生产力和表观利用率分别达17.87 kg∙kg^-1/17.85 kg∙kg^-1、67.27 kg∙kg^-1/71.28 kg∙kg^-1、74.93%/75.05%),最终实现高产。【结论】在麦/油-稻轮作下秸秆全量还田,配合N₂氮肥管理,可有效提高直播杂交稻氮素吸收、利用效率,增加籽粒产量,尤以油菜秸杆还田的效果更好。     

芸薹素内酯对稻草基质育秧水稻秧苗生理特性及栽后生长的影响

【目的】筛选出机插水稻基质育秧芸薹素内酯(BR)适宜的施用方法及最佳用量。【方法】以中早39为供试材料,采用稻草基质旱育秧方式,探究BR不同处理方式和浓度对机插早稻秧苗生理特性及栽后生长的影响。【结果】施用BR可以提高秧苗的抗氧化保护酶活性,降低丙二醛含量,增加可溶性蛋白含量、总糖含量及C/N,秧苗根系活力提高了13.24%~48.31%,利于形成抗性强的健壮秧苗;喷施方式对提高秧苗超氧化物歧化酶、过氧化物酶、过氧化氢酶活性效果最佳,基施方式对降低秧苗丙二醛含量效果最好。施用适量BR也可促进秧苗机插后长出新叶、新根及返青,喷施方式效果最好;浸种、喷施方式还能增强秧苗机插后20~30 d的单株分蘖力。【结论】播种前和出苗后进行两次适量的BR处理,有利形成壮苗和栽后活棵返青及分蘖,以播前0.15 mg/L浸种和秧苗1叶1心期0.10 mg/L喷施效果为好。     

麦油稻轮作秸秆还田与施氮对水稻光合特性及产量的影响

以宜香优2115为材料,采用二因素裂区设计:主区设小麦或油菜秸秆全量翻埋还田(M_1)和秸秆不还田对照(M_0);副区设4个氮肥管理,不施氮(N_0),基肥、分蘖肥、促花肥、保花肥氮肥施用比例为10∶0∶0∶0(N_1),基肥、分蘖肥、促花肥、保花肥氮肥施用比例为3∶3∶2∶2(N_2),基肥、分蘖肥、促花肥、保花肥氮肥施用比例为2∶2∶3∶3(N_3),研究秸秆还田和氮肥管理对直播稻的光合特性、干物质积累及产量的影响。结果表明:麦–稻或油–稻轮作下,氮肥管理对直播稻主要生育时期的干物质积累、光合特性及产量均存在显著或极显著的调控效应,秸秆还田显著影响水稻拔节期、齐穗期的叶面积指数(LAI)及群体干物质积累,同时油–稻轮作下其调控效应高于麦–稻轮作模式。秸秆不还田时,配合N_3施肥方式,可有效提高直播稻结实期剑叶净光合速率、SPAD值和叶面积指数,延缓叶片衰老,且在拔节期至成熟期间保持较高的群体生长率,干物质积累优势明显;秸秆还田下,配以基肥、分蘖肥、促花肥、保花肥氮肥施用比例为3∶3∶2∶2的管理模式,麦茬或油茬直播稻群体构建合理,结实期剑叶光合能力强,有效穗、每穗粒数较多,表现高产,产量最高可达10 090、10 693 kg/hm~2。综合分析,麦–稻或油–稻轮作下秸秆还田,配合基肥、分蘖肥、促花肥、保花肥氮肥施用比例为3∶3∶2∶2的氮肥管理模式,能实现直播稻的高产稳产。     

林木采伐及木材精深加工机器人研究进展

林木采伐及木材精深加工与木材生产的效益息息相关，机器人在木材生产中的应用促进了木材生产质量和效率，为木材工业发展提供了新的增长动力。针对机器人在林木采伐及木材精深加工领域的应用，文中从林木采伐、人造板生产、家具制造3方面详细论述了采伐机器人、旋切定心机器人、喷涂机器人、码垛机器人、弯曲木机器人、雕刻机器人等机器人研究现状，提出未来林木采伐及木材精深加工机器人的发展方向应集中于仿生移动机构、多功能集成机器人、智能算法及柔性制造系统等方面。     

小麦秸秆复合基质对番茄幼苗生长发育的影响

为了充分利用农业废弃物小麦秸秆,进行草炭替代性育苗基质原料的研发,实现农业资源循环化利用和生态可持续发展。以番茄‘毛粉802’为材料,通过小麦秸秆腐熟物、草炭、蛭石和珍珠岩4种基质原料及1种生物菌肥进行不同体积配比处理,研究不同配比的小麦秸秆复合基质对番茄幼苗生长指标、叶片色素及荧光指标、幼苗叶片理化性质指标、基质生物指标和理化性质的影响,探究适合番茄幼苗生长的小麦秸秆复合育苗基质配方。利用灰色关联法对19项指标进行综合分析。结果表明,V腐熟小麦秸秆∶V蛭石∶V珍珠岩∶V生物菌肥=6∶2.5∶1∶0.5番茄幼苗表现最好,而番茄幼苗在纯小麦秸秆腐熟物上的生长量远远低于其他处理,番茄幼苗的表现最差。     

Asterosaponins: Structures,Taxonomic Distribution,Biogenesis and Biological Activities

Asterosaponins are a class of steroid oligoglycosides isolated from starfish with characteristic structures and diverse biological activities. In this review, we have attempted to combine the most important data concerning asterosaponins and give a list of these secondary metabolites with their structural peculiarities. The purpose of this review is to provide a brief but as complete as possible principal information about their chemical structures, taxonomic distribution in the marine environment, distribution in different geographical areas and depths, some properties, biological activities, and functions. Some other rare steroid metabolites from starfish, closely related in structures and probably biogenesis to asterosaponins, are also discussed.     

基于信息抽取的食品安全事件自动问答系统方法研究

针对从海量食品安全事件新闻报道中很难抽取出所需答案的问题，以食品安全事件语料库为研究对象，提出了一种基于信息抽取技术的自动问答系统。首先，利用深度学习模型TextCNN对用户输入的问题进行分类，得到其所属类型。其次，对于输入问题，借助Lucene搜索引擎找到其最佳匹配文档。再次，根据输入问题的类型，从食品安全事件数据库（采用信息抽取技术自动提取的一个结构化数据库）中筛选出该文档所包含的答案候选句集合。最后，利用深度学习模型Bi LSTM及基于答案候选句上下文的特征提取方法构建一个答案抽取模型，该模型能从给定的答案候选句集合中提取出最终答案。为检查基于食品安全事件数据库的答案候选句筛选方式及基于答案候选句上下文的特征提取方式对整个自动问答系统性能的影响，进行了多种比较实验，结果表明含有基于食品安全事件数据库的答案候选句筛选方式和基于答案候选句上下文的特征提取方式的问答系统表现最佳，其回答准确率达到44%。这相比于传统的问答系统，具有明显的优势。     

Effects of different tillage and straw retention practices on soil aggregates and carbon and nitrogen sequestration in soils of the northwestern China

Soil tillage and straw retention in dryland areas may affect the soil aggregates and the distribution of total organic carbon. The aims of this study were to establish how different tillage and straw retention practices affect the soil aggregates and soil organic carbon (SOC) and total nitrogen (TN) contents in the aggregate fractions based on a long-term (approximately 15 years) field experimentin the semi-arid western Loess Plateau, northwestern China. The experiment included four soil treatments, i.e., conventional tillage with straw removed (T), conventional tillage with straw incorporated (TS), no tillage with straw removed (NT) and no tillage with straw retention (NTS), which were arranged in a complete randomized block design. The wet-sieving method was used to separate four size fractions of aggregates, namely, large macroaggregates (LA, >2000 μm), small macroaggregates (SA, 250-2000 μm), microaggregates (MA, 53-250 μm), and silt and clay (SC, <53 μm). Compared to the conventional tillage practices (including T and TS treatments), the percentages of the macroaggregate fractions (LA and SA) under the conservation tillage practices (including NT and NTS treatments) were increased by 41.2%-56.6%, with the NTS treatment having the greatest effect. For soil layers of 0-5, 5-10 and 10-30 cm, values of the mean weight diameter (MWD) under the TS and NTS treatments were 10.68%, 13.83% and 17.65%, respectively. They were 18.45%, 19.15% and 14.12% higher than those under the T treatment, respectively. The maximum contents of the aggregate-associated SOC and TN were detected in the SA fraction, with the greatest effect being observed for the NTS treatment. The SOC and TN contents were significantly higher under the NTS and TS treatments than under the T treatment. Also, the increases in SOC and TN levels were much higher in the straw-retention plots than in the straw-removed plots. The macroaggregates (including LA and SA fractions) were the major pools for SOC and TN, regardless of tillage practices, storing 3.25-6.81 g C/kg soil and 0.34-0.62 g N/kg soil. Based on the above results, we recommend the NTS treatment as the best option to boost soil aggregates and to reinforce carbon and nitrogen sequestration in soils in the semi-arid western Loess Plateau of northwestern China.     

不同水平的青贮饲料对饲喂稻草秸秆奶牛瘤胃微生物数量和微生物蛋白合成的影响

本试验的目的是确定饲粮中青贮银合欢添加水平对奶牛瘤胃微生物种群、氮平衡和微生物蛋白合成的影响。试验采用4×4拉丁方设计,选择12头初始体重为163±16 kg、带有瘤胃瘘管的奶牛,随机分为4个组,每组3个重复,每个重复1头牛。基础日粮以100%的水稻秸秆为原料,处理组分别用30%、60%和100%的青贮银合欢替代水稻秸秆,奶牛自由采食水稻秸秆和青贮银合欢,每天按照体重的0.2%补充浓缩料。结果表明,用60%青贮银合欢替代水稻秸秆组奶牛瘤胃微生物群,尤其是纤维素分解菌、蛋白分解菌和厌氧真菌的数量显著增加(P<0.05),各组对淀粉分解菌群无显著影响(P>0.05)。原生动物种群数量随日粮青贮银合欢添加水平的增加呈线性下降(P<0.05)(P<0.05)。此外,氮平衡和微生物蛋白合成均随着日粮青贮银合欢添加水平的升高而升高(P<0.05),其中以60%青贮银合欢组最高。结论:在本试验基础上,用60%青贮银合欢替代水稻秸秆可以显著提高奶牛体内的微生物数量和微生物蛋白的合成。