雅安市主要造林树种苗木质量的分级研究

对2006年雅安各县苗圃主要造林树种苗木进行调查,以地径(D)和苗高(H)作为质量指标,采用逐步聚类分析对苗木质量进行分级,结合生产实际探讨了雅安市主要造林树种苗木标准。其中有些树种的苗木分级标准为首次研究。标准中各指标均大于现行国家标准,能较好地反映实际生产水平,为育苗生产和制定地方标准提供了参考。     

Accounting for unknown foster dams in the genetic evaluation of embryo transfer progeny

Animals born by embryo transfer (ET) are usually not included in the genetic evaluation of beef cattle for preweaning growth if the recipient dam is unknown. This is primarily to avoid potential bias in the estimation of the unknown age of dam. We present a method that allows including records of calves with unknown age of dam. Assumptions are as follows: (i) foster cows belong to the same breed being evaluated, (ii) there is no correlation between the breeding value (BV) of the calf and the maternal BV of the recipient cow, and (iii) cows of all ages are used as recipients. We examine the issue of bias for the fixed level of unknown age of dam (AOD) and propose an estimator of the effect based on classical measurement error theory (MEM) and a Bayesian approach. Using stochastic simulation under random mating or selection, the MEM estimating equations were compared with BLUP in two situations as follows: (i) full information (FI); (ii) missing AOD information on some dams. Predictions of breeding value (PBV) from the FI situation had the smallest empirical average bias followed by PBV obtained without taking measurement error into account. In turn, MEM displayed the highest bias, although the differences were small. On the other hand, MEM showed the smallest MSEP, for either random mating or selection, followed by FI, whereas ignoring measurement error produced the largest MSEP. As a consequence from the smallest MSEP with a relatively small bias, empirical accuracies of PBV were larger for MEM than those for full information, which in turn showed larger accuracies than the situation ignoring measurement error. It is concluded that MEM equations are a useful alternative for analysing weaning weight data when recipient cows are unknown, as it mitigates the effects of bias in AOD by decreasing MSEP.     

构建高职高专食品检测类专业实践课程的渐进式探究性教学体系研究

在分析高职高专食品检测类专业的实践课教学现存主要问题的基础上,将“渐进式”教学方法和“探究性”学习理论结合,引入高职高专食品检测类专业的实验和综合实训课程教学中,创设了实验课到综合实训课的“渐进式探究性”的教学体系,以期构建一个适合高职高专食品检测类专业的实践课程的关联教学体系,完全意义上实现教学与职业的“零距离”对接,以及高端技能型专门人才培养的目标.“专业表述能力”和“现场管理能力”是高端技能型专门人才应具备的基本专业素质,是实现岗位零距离对接的基本条件,在此首次将其列入学生能力的考评体系,为力争全新人才的培养奠定坚实基础,以推动“中国教育升级”.     

近50年中国东部林区最高气温序列

运用线性回归插补途径和RHtest方法分别对1961-2010年我国东部林区853个站点的日最高气温资料进行插补和均一化检验订正,建立完整且均一的日最高气温数据集.在此基础上,对比分析我国东部林区近50年来最高气温订正前后的变化特征.结果表明:订正后东部林区年及四季(春、夏、秋、冬)平均最高气温每10年分别增加0.171,0.233,-0.002,0.201和0.263℃,订正后整个区域年平均最高气温均呈上升趋势,而订正前有部分站点呈降温趋势;春、秋、冬3季平均最高气温在整个林区几乎全部呈现上升趋势,夏季东部林区多数站点呈降温趋势,尤其是长江和黄河流域之间的区域.     

Grapes＿meso数值模式预报对石河子定量降水检验研究

为了了解Grapes_meso数值模式预报对石河子垦区的预报能力,提高预报降水的准确率,利用TS评分对2017年11月至2018年9月的Grapes_meso数值模式降水资料进行了24h的时效检验分析。结果表明:晴雨检验的结果与石河子垦区降水气候概率基本一致,即表现为降水少的地方晴雨准确率较高,降水多的地方晴雨准确率低的空间分布特征。一般性降水检验存在较强的季节性,表现为春秋季降水准确率高于夏冬季。分级检验中小雨的准确率明显高于其他量级。此外,Grapes_meso数值模式对暴量雨雪的预报能力较差。     

Can soil respiration estimate neglect the contribution of abiotic exchange？

This study examines the hypothesis that soil respiration can always be interpreted purely in terms of biotic processes, neglecting the contribution of abiotic exchange to CO2 fluxes in alkaline soils of arid areas that characterize 5% of the Earth’s total land surface. Analyses on flux data collected from previous studies suggested reconciling soil respiration as organic(root/microbial respiration) and inorganic(abiotic CO2 exchange) respiration, whose contributions in the total CO2 flux were determined by soil alkaline content. On the basis of utilizing meteorological and soil data collected from the Xinjiang and Central Asia Scientific Data Sharing Platform, an incorporated model indicated that inorganic respiration represents almost half of the total CO2 flux. Neglecting the abiotic module may result in overestimates of soil respiration in arid alkaline lands, which partly explains the long-sought "missing carbon sink".     

光束阻断式小粒蔬菜种子漏充与堵孔同步检测系统研究

针对气力式排种器直播小粒蔬菜种子时易产生漏充与堵孔的问题,设计了一种光束阻断式小粒蔬菜种子漏充与堵孔同步检测系统。该检测系统调用ARM嵌入式系统的中断资源,采用旋转编码器实时测定排种盘转速,实时调整时间窗口与理论脉冲频率;在时间窗口内采集对射型激光传感器的输出脉冲,计算实际脉冲频率;通过对理论脉冲频率和实际脉冲频率实施运算,同步测定漏充率与吸孔堵塞率,并在触摸屏上显示。选用雪白玉萝卜、中双11号油菜和上海青3种蔬菜种子为研究对象,以排种盘转速和吸室真空度为试验因素,以漏充率和吸孔堵塞率为试验指标,在气力式精量排种器上进行该系统与高速摄像同步检测试验验证。试验结果表明,该系统可根据排种盘转速变化自行调整时间窗口,对漏充判断相对偏差不大于1.67%,对吸孔堵塞判断相对偏差不大于0.95%。该方法能够有效实现小粒蔬菜种子漏充与堵孔的实时同步检测,为解析排种器漏播成因与排种器改进设计提供依据。     

基于缺失面板数据分析粮食产量与影响因素的关系

为我国粮食生产提供参考,利用2003—2011年的省际面板数据,在部分数据缺失的情况下,对缺失数据进行填补,结合ARMA模型及空间相关性,进而利用完备面板数据对粮食单产进行分位数回归,分析各影响因素在不同分位点上与粮食单产的关系。结果表明:有效灌溉面积比例、单位面积化肥施用量、单位耕地动力及粮食类零售价格增长指数对单位面积粮食产量起促进作用,农业生产资料价格增长指数对粮食单产作用为负,单位劳动力对其影响在各分位点表现不一。保证耕地面积、提高灌溉效率、积极预防自然灾害对粮食产量的提高至关重要。     

马铃薯精密播种机智能控制系统设计

针对现有马铃薯播种机播种株距控制精准度不高、易产生重种漏种等问题,研发了一种由主控制模块、检测模块、株距控制模块和振动强度控制模块等7个模块组成的马铃薯精密播种机智能控制系统,采用液压马达控制薯种输送带运转,步进电机控制薯种输送带的振动强度,实现了播种株距和重种漏种率的自动控制.试验结果表明,播种速度相同时,实际播种株距相对于设定播种株距的平均偏差依次增大,播种速度越高实际播种株距的稳定性越差;薯种输送带振动强度越强,重种率越低,漏种率越高,各因素对重种漏种率影响的主次顺序为:薯种输送带振动强度＞播种速度＞薯种质量,且薯种输送带振动强度对重种率、薯种输送带振动强度和播种速度对漏种率有显著影响;较佳的播种作业参数为:薯种输送带振动强度为Ⅱ级(即轻微振动时)、播种速度为1.16 m/s及薯种质量为35 g.经2～3个周期即可调整到允许范围内,且稳定性好.因此,完全能够满足种植户的实际播种作业要求,为智能控制马铃薯精密播种装备的后续研发提供参考.