A multicenter, matched case-control study of risk factors for equine laminitis

Risk factors for equine laminitis were examined in a prospective case-control study of the 258 cases seen at six collaborating veterinary teaching hospitals over a 32-month period. Case-control pairs were matched on institution, clinician, and season of diagnosis. The 90% of case-control pairs (78 acute, 155 chronic) that had complete data for age, gender, and breed were used in separate conditional logistic-regression models for acute and chronic laminitis. There was an increase in risk for horses with acute laminitis from 5 to 7 years of age (OR 4.7, 95% CI 1.3–16) and from 13 to 31 years of age (OR 3.9, 95% CI 1.3–12) (both compared to <5 years); risk was increased for chronic laminitis from 10 to 14 years (OR 3, 95% CI 1.4–6.8) and from 15 to 38 years (OR 2.9, 95% CI 1.4–6.1) (both compared to <6 years). Mares — but not stallions — were more likely than geldings to develop acute laminitis (OR 2.6, 95% CI 1.1–6.2) and chronic laminitis (OR 2.0, 95% CI 1.1–3.6). In the small acute-laminitis data set, the breed variable was collapsed into three categories: Thoroughbred (THB, reference), the Quarter Horse (QH), and other (non-QH-THB). The non-QH-THB group was at increased risk of acute laminitis (OR 3.8, 95% CI 1.2–11.8). For the seven breed-group categories used in the chronic-laminitis model, however, all non-THB breed groups appeared significantly at risk as compared to the THB, with odds ratios ranging from 3.3 (95% CI 1.3–8.30) for the QH to 9.1 (95% CI 2.1–39.3) for ponies.     

氮沉降对细根动态和形态特征的影响研究进展

旨在总结前人研究经验以及过去研究的不足,指出未来N沉降对于细根影响研究的发展方向。基于前人研究的成果,总结了N沉降是如何影响细根动态和形态特征,进而又如何影响生态系统C循环。详细分析了全球N沉降现状,表明N沉降呈逐年加重的趋势;分析了细根动态（细根周转和呼吸）和形态特征（根长、直径、生物量、化学组分）对N沉降的响应。既有研究提供了很多N沉降影响细根动态和形态特征的证据,这些证据对于未来开展细根综合研究具有重要借鉴意义。     

河北省沙尘天气时空分布特征及影响因素分析

利用20个基础气象站1980-2006年的气象观测数据,对河北省沙尘天气的时空分布特征及其影响因素进行了分析研究.结果表明,河北省沙尘天气以扬沙为主;在空间分异上,沙尘天气自西向东发生频次递减,西北部和南部是沙尘天气的高发区,东部是沙尘天气的低发区,各类沙尘天气的高发中心不尽相同.在年际变化上,扬沙、浮尘和沙尘暴3类沙尘天气均呈逐年波动减少的趋势,春季发生次数最多;气候周期性变化是造成沙尘天气年际年内变化的主要原因,大风与沙尘源地的耦合决定了沙尘天气的空间分布特征.     

Systemic View on Heading and Overwintering: Are They Always Opposed?

The study investigated the cultivars of non‐obligatorily requiring vernalization plant Festulolium braunii and assessed the influence of non‐hardy reproductive and hardy vegetative structures on overwintering effect. The study was conducted taking into account systemic relations between these types of structures. The results show the cultivars differ according to the percentage of headed and overwintered plants, when the cultivars with the most abundant heading – ‘Felopa’ and ‘Sulino’ – are also better at overwintering. The positive correlation between heading and overwintering characteristics was also observed, what seemed to be a rather new finding. It can be explained by systemic effect: non‐hardy later reproductive structures induce the post‐generative regrowth of vegetative shoots, which during shorter days halt development and become potentially hardy. More detailed interpretation is also provided including discussion of causal mechanisms of the detected phenomenon. The authors suppose that these mechanisms constitute a survival strategy for such perennial plants. The observed late heading which represents reproductive structures could be applied in plant breeding as a marker of winter‐hardiness among perennial grass plants which non‐obligatorily demand vernalization.     

固相微萃取技术在食用植物油分析中的应用

介绍了固相微萃取(SPME)技术的装置device、原理、萃取模式、影响因素、技术特点和应用范围;概述了SPME技术在植物油溶剂残留、香气组分分析、污染物的测定以及评估植物油氧化程度或氧化稳定性中的应用.     

硫酸铜对柑橘和山麦冬炭疽病菌的影响

在PDA培养基培养条件下,研究不同浓度的CuSO4对柑橘炭疽病菌和山麦冬炭疽病菌生长状况、产孢量、孢子萌发率的影响。试验结果表明,与对照组相比,1 g/200mL CuSO4 5H2O对柑橘炭疽病菌和山麦冬炭疽病菌的影响最大,完全抑制了这两种病菌的生长和产孢;0.2 g/200mL CuSO4 5H2O对柑橘炭疽病菌和山麦冬炭疽病菌的影响也非常明显,不仅较大程度地抑制了这两种病菌的生长和产孢,而且使这两种孢子的萌发率均低于19%;0.1 g/200mL CuSO4 5H2O对柑橘炭疽病菌和山麦冬炭疽病菌的影响较大;0.02 g/mL CuSO4 5H2O对柑橘炭疽病菌和山麦冬炭疽病菌的影响较小。由此可以初步得出,0.2 g/200mL CuSO4 5H2O对柑橘炭疽病菌和山麦冬炭疽病菌的抑制效果显著,可以作为抑制这两种病菌的临界浓度。     

卫辉市能见度变化特征及与气象因子的相关性分析

为提高能见度的预测预报水平,减轻低能见度带来的危害,收集了卫辉市1991—2015 年水平能见度及地面气象要素资料,运用数理统计、相关系数等方法,分析了卫辉市能见度的变化特征及与气象因子的关联。结果表明：25 年来能见度的年际变化呈先减后增的特征,低谷出现在21 世纪初;四季中春季最好,冬季最差;一年中最低值出现在12 月,最高值出现在5 月;一日中上午和17 时以后较差,13—15时最好。大气低能见度和较差能见度出现的频率在2000 年以前呈波动上升趋势,2009 年以后呈波动下降趋势;一年中出现频率12 月最高,最小频率出现在7 月和5 月。能见度与相对湿度呈极显著负相关,与风速呈显著正相关,与气温和气压的相关关系不显著。     

2种保护性耕作技术对小麦产量的影响

以郑麦9023为试验材料,研究了2种保护性耕作技术对小麦分蘖数、穗粒数、千粒重、产量等指标的影响。试验结果表明,秸秆粉碎还田深耕的效果最好,有利于小麦的生长发育并能提高产量;而秸秆还田免耕对小麦生长发育及产量有不良影响。     

广东省江门地区农户新技术采用行为影响因素分析——以水稻“三控”施肥技术采用为例

[目的]深入了解广东省江门地区农户对新技术采用行为的主要影响因素,探索未来江门地区乃至广东省新技术推广工作的努力方向.[方法]以水稻“三控”施肥技术为例,以江门地区404个农户的调查数据为依据,通过Logistic回归模型对农户技术采用行为的影响因素进行定量分析.[结果]在广东省江门地区农户新技术采用行为影响因素中,技术接受难易程度、采用“三控”技术比传统种植的增产量、参加农技培训班次数、培训班对农户帮助情况与农户采用新技术的意愿呈显著正相关,尤其是技术接受难易程度、采用“三控”技术比传统种植的增产量与农户采用新技术的意愿达到了极显著水平,男性在新技术采用中起着决策的主导力量.[建议]应创新技术培训内容和方式、加强示范展示基地建设、加快农民专业合作社发展、加强政府引导和支持力度,以提高农民新技术采用率,促进农业新技术的推广.     

水合物聚集影响因素及正交试验研究

通过水合物聚集体受力分析确定了其主要聚集力是毛细液桥力,完善了水合物聚集体临界最大粒径计算模型.水合物聚集影响因素有接触角、油水界面张力、油相粘度、水合物体积分数、剪切速率,分析单一因素变化对水合物聚集的影响,发现油水界面张力增大导致聚集加剧,其他因素增大则会抑制水合物聚集.以水合物聚集体临界最大粒径作为聚集程度的评判指标,利用正交试验确定了因素水平的最优组合,水合物体积分数作为影响最大的因素,需要首先将其控制在最优水平.研究成果可为确保管输水合物浆稳定流动提供支持.（表3,图7,参14）