利用仪器检测指标量化夏橙化渣程度

为了量化评价夏橙化渣程度,利用仪器检测的指标建立夏橙感官化渣程度的预测模型,采集了湖北宜昌秭归的9种夏橙总计270个样品,首先测定了影响夏橙样本化渣程度的粗纤维成分含量,进行了夏橙化渣程度的感官评定分析,再利用质构仪的压缩试验、质地剖面TPA(texture profile analysis)试验、剪切试验模拟了口腔咀嚼果肉的过程。结果表明,粗纤维成分含量与质构参数之间存在显著相关性,质构参数与感官化渣程度之间的相关关系也十分显著,说明夏橙质构特性可以表征果肉的化渣性。进一步采用主成分回归分析法,以仪器测得的质构特征值为自变量,感官化渣程度为因变量进行回归分析,得到具有统计学意义决定系数R2为0.73的预测模型。由此表明,基于质构特性建立的夏橙化渣程度评价模型在一定程度上可以准确地评价夏橙的化渣程度,利用质构特性取代感官评定评价夏橙化渣程度是可行的,该研究可为夏橙化渣程度的检测提供参考。     

永定烟后稻测土配方施肥试验

在烟后稻上进行测土配方施肥试验。结果表明,测土配方施肥比习惯施肥每667m^2增产稻谷15．6kg,净增收47．06元;测土配方施肥比空白对照每667m^2增产稻谷145．1kg,净增收331．6元,烟后稻测土配方施肥能增产增效。     

A Comparison of the Elemental Composition of Leaf Tissue of Spartina Patens and Spartina Alternifora in Louisiana’s Coastal Marshes

Elemental concentrations in leaf tissue can identify limiting conditions in crops and can be useful in managing and restoring marshes. Coastal management and restoration plans frequently include Spartina spp. because they are common plants in coastal wetlands across North America. Researchers frequently compare results of stoichiometric studies among Spartina spp. to corroborate results, although their stoichiometry may not be comparable. We compare the stoichiometry of paired samples of Spartina patens and Spartina alterniflora collected across Louisiana. Overall differences in stoichiometry between species, seasonal changes, and effects of porewater chemistry were quantified. Manganese (Mn) concentrations and calcium (Ca) concentrations were higher in S. alterniflora and the difference in [Ca] increased seasonally. Sodium concentrations were similar, except during prolonged inundation. Short flooding durations decreased carbon (C):nitrogen (N) without increasing [Mn] or flooding stress in both species.     

林木花粉采集、保存及活力检测的研究进展

文章综述近年来有关林木花粉研究的相关报道,主要从花粉采集、保存以及活力测定等方面的研究内容进行阐述并提出建议,旨在为今后开展林木花粉研究提供理论参考,为人工授粉、杂交育种等提供重要的理论依据与技术支撑。     

人造板弹性模量检测方法及其研究现状

弹性模量是人造板重要的力学性能指标之一,它是表征人造板刚度性能的重要指标,与其他的力学指标也有密切的关系,直接影响人造板的使用.对国内外人造板弹性模量的检测方法及其研究现状进行了归纳总结,指出振动、应力波、机械应力等无损检测方法是今后发展方向之一.     

茶陵县杂交中稻测土配方施肥效应模型研究

通过连续6a的田间试验,分析比较了茶陵县杂交中稻的相对产量、相对吸收量与土壤肥力的关系,根据杂交中稻的N、P、K养分相对吸收量划分土壤N、P、K丰缺指标。采用三元二次回归,建立了不同肥力条件下杂交中稻的N、P、K肥料效应模型,依据模型提出了不同肥力水平(目标产量)下杂交中稻的测土配方最佳施肥用量及施肥技术。     

浅谈计算机视觉技术在果蔬外观品质检测中的应用

果蔬的外观品质是评估其市场价值、被消费者选择的依据之一,而且在某种程度上也会影响它们的内部品质。本文分析了计算机视觉系统对果蔬外部品质检测的发展现状,提出了计算机视觉技术在南疆果蔬外观品质检测中存在的问题及建议,旨在为新疆南疆地区水果和蔬菜品质检测技术的研究和发展提供参考。     

湘潭市市辖区耕层土壤养分变化

依托湘潭市市辖区测土配方施肥项目实施,通过对2009-2012年土壤样品化验数据分析,初步摸清了耕地耕层土壤的养分含量水平,并对土壤样品状况进行分级评价。结果表明,2009-2012年湘潭市市辖区耕层土壤的pH平均值分别为5.8、5.9、5.9和5.6,处于低等级土壤pH的耕地面积从2009年的34.85%增加到2012年的47.35%,土壤有酸化趋势;土壤有机质含量平均值分别为34.3、35.4、32.4和37.0 g/kg,碱解氮含量平均值分别为169.0、160.6、190.8和164.1 mg/kg,平均93.07%土壤有机质和98.87%土壤碱解氮的耕地处于适宜、高和极高的等级,土壤有机质和碱解氮含量偏高;有效磷含量平均值分别为13.2、18.3、10.3和31.9 mg/kg,前三年土壤有效磷含量偏低,平均83.94%处于极低、低和适宜的等级,2012年骤然增加并高于适宜等级,有82.17%处于适宜、高和极高的等级;速效钾含量平均值分别为125.6、169.7、116.7和148.0 mg/kg,平均78.84%的土壤速效钾处于低和适宜的等级,土壤速效钾含量偏低。     

论能力验证在水质监测中的重要性(英文)

作为一个水质监测数据发布机构,监测数据的重要性毋庸置疑,能力验证作为提高监测能力,加强实验室质量管理的手段之一,对保证监测数据的准确性、完整性、可比性具有十分重要的意义。该研究通过分析能力验证在水质监测中的积极作用,结合该单位参加的实验室能力验证工作,讨论了如何通过能力验证提高水质监测能力和实验室质量管理水平。     

Diagnostic assessment without cut-offs: Application of serology for the modelling of bovine digital dermatitis infection

Bovine digital dermatitis (BDD) is an epidermitis which is a leading cause of infectious lameness. The only recognized diagnostic test is foot inspection, which is a labour-intensive procedure. There is no universally recognized, standardized lesion scoring system. As small lesions are easily missed, foot inspection has limited diagnostic sensitivity. Furthermore, interpretation is subjective, and prone to observer bias. Serology is more convenient to carry out and is potentially a more sensitive indicator of infection. By carrying out 20 serological assays using lesion-associated Treponema spp. isolates, three serogroups were identified. The reliability of the tests was established by assessing the level of agreement and the concordance correlation coefficient. Subsequently, an ELISA suitable for routine use was developed.The benchmark of diagnostic test validation is conventionally the determination of the key test parameters, sensitivity and specificity. This requires the imposition of a cut-off point. For serological assays with outcomes on a continuous scale, the degree by which the test result differs from this cut-off is disregarded. Bayesian statistical methodology has been developed which enables the assay result also to be interpreted on a continuous scale, thereby optimizing the information inherent in the test. Using a cross-sectional study dataset carried out on 8 representative dairy farms in the UK, the probability of infection, P(I), of each individual animal was estimated in the absence of a ‘Gold Standard’ by modelling I as a latent variable which was determined by lesion status, L as well as serology, S. Covariate data (foot hygiene score and age) were utilized to estimate P(L) when no lesion inspection was performed. Informative prior distributions were elicited where possible. The model was utilized for predictive inference, by computing estimates of P(I) and P(L) independently of the data.A more detailed and informative analysis of the farm-level distribution of infection could thus be performed. Also, biases associated with the subjective interpretation of lesion status were minimized. Model outputs showed that young stock were unlikely to be infected, whereas cows tended to have high or low probabilities of being infected. Estimates of probability of infection were considerably higher for animals with lesions than for those without. Associations were identified between both covariates and probability of infection in cows, but not in the young stock. Under the condition that the model assumptions are valid for the larger population, the results of this work can be generalized by predictive inference.