Methods for measuring stiffness of young trees

clones with high modulus of elasticity (MOE). Various ways of measuring MOE are examined: traditional static bending, axial compression of bolts, existing sonic methods, as well as a tool specifically configured for resonance on short bolts. Wood characteristics and microfibril angle are measured on discs taken from each tree. Results show a good correlation between acoustic and static measurements of modulus of elasticity. Moreover, the selected seven radiata clones differ in stiffness by a factor of two, and much of this variation seems to relate to differences in microfibril angle. The results validate the assumption that there is potential to improve wood stiffness of radiata pine genetically. This work does not offer definitive solutions but explores a number of approaches that could be utilised as a selection tool in tree breeding for better product performance of radiata lumber. Here, development of methods based on acoustics is shown to assist in the necessary mass screening of clones for stiffness properties.     

Influence of wastewater vs groundwater on young Citrus trees

The use of wastewater as an alternative water resource for irrigation needs specific studies to evaluate its effect on different soils and crops. Young Citrus trees have been irrigated with wastewater from a sewage treatment plant during three consecutive seasons and the growth, leaf mineral status and fruit quality measured. Some differences have been found between groundwater and wastewater composition. Sodium ion, chloride ion, organic matter and boron concentrations were always higher in wastewater. In contrast, high nitrate levels were found in groundwater, probably due to aquifer contamination. In all seasons the values of soil‐analysed elements were within the optimal ranges for this kind of crop and soil. Levels of sodium, chloride and boron in leaf tissue were below the toxic levels for Citrus. Leaf nitrogen content was in the optimal nutrition range and no significant difference was observed between samples from trees irrigated with wastewater and groundwater. Both growth and fruit quality parameters were unaffected by the high levels of sodium, chloride and boron in wastewater. Collectively our data show that no detrimental effects are found after using wastewater for irrigation of young Citrus trees. More importantly, fertiliser rates could be lowered significantly without reducing yields or affecting leaf nutrient levels when using reclaimed wastewater. Thus reclaimed wastewater appears to be a suitable alternative water resource for irrigation of Citrus trees. © 2000 Society of Chemical Industry     

Technical note: Methods for interim prediction of single-step breeding values for young animals

Single-step genomic evaluations have the advantage of simultaneously combining all pedigree, phenotypic, and genotypic information available. However, systems with a large number of genotyped animals have some computational challenges. In many genomic breeding programs, genomic predictions of young animals should become available for selection decisions in the shortest time possible, which requires either a very effective estimation or an approximation with negligible loss in accuracy. We investigated different procedures for predicting breeding values of young genotyped animals without setting up the full single-step system augmented for the additional genotypes. Methods were based on transmitting the information from single-step breeding values of genotyped animals that took part in the previous full run to young animals, either through genomic relationships or through a marker-based model. The different procedures were tested on real data from the April 2017 run of the German-Austrian official genomic evaluation for Fleckvieh. The data set included 62,559 genotyped animals and was used to run single-step evaluations for 23 conformation traits. A further data set comprising 1,768 young animals was used for interim prediction and we called it the validation set. The reference values for validation were the predicted breeding values of the young animals from a full single-step run containing the genotypes of all 64,327 animals. Correlations between the approximated predictions and those from the full single-step run also containing genotypes from young animals averaged 0.9932 for the best method (from 0.990 to 0.995 across traits). In conclusion, prediction of single-step breeding values for young animals can be well approximated using systems of size equal to the number of markers.     

The variability of urinary cotinine levels in young children: implications for measuring ETS exposure.

This study examined the within-subject variability of urinary cotinine levels in young children (aged = 0.6-7.2 years) of smoking parents to determine the number of urine samples needed to provide accurate estimates of exposure to environmental tobacco smoke (ETS) for different time intervals. Secondary analyses were conducted of five independent studies (N = 376), in which multiple urinary cotinine measures had been collected over time periods up to 13 months. Over measurement periods of 4-15 days, the within-subject cotinine levels varied 3-5 times more than would be expected based on measurement error alone. Over 7-13 months, the within-subject variability was 10-20 times higher than would be expected based on the measurement error. Findings indicated that cotinine measures from single urine samples provided highly accurate estimates of only recent exposure (i.e., 2-3 days; rho = 0.99). To achieve similarly precise estimates of the mean cotinine level of an individual child over 4-15 days, up to nine urine samples may be necessary. Up to 12 urine samples may be required to achieve similarly precise estimates of ETS exposure over a 4- to 13-month period. Epidemiologic and clinical research on ETS exposure in children can benefit from multiple urine samples (a) to accurately measure average exposure at the level of the individual child, (b) to describe temporal patterns, (c) to detect incidences of peak exposure that would remain underrecognized if monitoring is limited to a single time point, and (d) to establish stable baseline levels and endpoints based on urine samples collected over clinically relevant time periods.     

Selecting trees for structural timber

Twenty-eight cubic metres of timber (i.e. a total of 2248 boards) cut from 108 Pinus radiata trees from two 25-year-old plantations from Canterbury and Nelson in the South Island of New Zealand were tested in tension. Within- and between-tree variations of stiffness, strength and density were examined. Comparisons between density and stiffness for selecting trees for structural timber indicated that stiffness is the better parameter for selecting superior trees within the natural population of a forest stand; and the quality and grade recovery of structural timber would be increased significantly if trees were to be selected on the basis of stiffness. These conclusions apply to both stands although regional differences are evident with the Nelson timber being somewhat stiffer.     

Methods for measuring water activity (aw) of foods and its applications to moisture sorption isotherm studies

Moisture sorption isotherm is commonly determined by saturated salt slurry method, which has defects of long time cost, cumbersome labor, and microbial deterioration of samples. Thus, a novel method, a_w measurement (AWM) method, has been developed to overcome these drawbacks. Fundamentals and applications of this fast method have been introduced with respects to its typical operational steps, a variety of equipment set-ups and applied samples. The resultant rapidness and reliability have been evaluated by comparing with conventional methods. This review also discussed factors impairing measurement precision and accuracy, including inappropriate choice of predryingwetting techniques and unachieved moisture uniformity in samples due to inadequate time. This analysis and corresponding suggestions can facilitate improved AWM method with more satisfying accuracy and time cost.     

Influence of rootstock on drought response in young 'Gale Gala' apple (Malus domestica Borkh.) trees

BACKGROUND: Drought is a major environmental stress limiting plant growth, productivity, and survival worldwide. Rootstocks are widely used to enhance plants resistance to drought stresses. This study determined influence of rootstock on drought responses in 1‐year‐old ‘Gale Gala’ apple trees grafted onto Malus sieversii or M. hupehensis. RESULTS: Choice of rootstock resulted in differential response to drought stress. Specifically, M. sieversii caused less drought‐induced reduction in relative growth rate, biomass accumulation, leaf area, leaf chlorophyll content, relative water content, photosynthesis rate and maximum chlorophyll fluorescence yield but greater increase in whole‐plant water use efficiency compared to M. hupehensis. Secondly, compared with M. hupehensis, M. sieversii caused less drought‐induced accumulation of reactive oxygen species but more increase in activities of antioxidant enzymes. In addition, xylem sap abscisic acid concentration was greater in trees grafted onto M. hupehensis than in those grafted onto M. sieversii under drought stress. CONCLUSION: ‘Gale Gala’ trees' response to drought stress was associated with the rootstock's genotype onto which it was grafted. Trees with M. sieversii as rootstock are more drought resistant than trees with M. hupehensis as rootstock, which suggests that M. sieversii can be widely used as rootstock in arid and semi‐arid regions. Copyright © 2012 Society of Chemical Industry     

Effect of time of application of fertiliser nitrogen on the distribution and identity of the nitrogenous constituents of young apple trees

The initial response to an application of fertiliser N appeared always as a rise in the level of asparagine. Following spring and summer N applications this high level of asparagine later decreased as those of arginine and the insoluble N increased, but after autumn N application both asparagine and arginine accumulated, especially in the roots. Leaves were exceptional both in containing a high proportion of insoluble N at all times and in containing a large amount of soluble glutamine soon after spring N application, in addition to the arginine and asparagine. Direct analyses have been transformed on to a weight basis and the results are given diagrammatically as the total weight of N present in each tissue of the tree as each of the four components: insoluble N, soluble arginine, soluble asparagine, or the total of all other soluble compounds. This has enabled the movement of N within the whole tree and the interchange between compounds in response to season and to fertiliser application to be recognised more readily. The possible significance of the relative mobilities of arginine and asparagine is also discussed, together with the possible merits of sampling leaves or other tissues, for example the roots, for predicting the future crop potential of apple trees.     

Probiotics for the young and the not so young

Although interest in the effects of the intestinal flora on health dates from the beginning of the 20th century, controlled clinical trials did not begin until its end. Oral administration of probiotic lactobacilli has been shown to alleviate and prevent atopic eczema. Similar effects were accomplished by administering fructose and glucose oligosaccharides (prebiotics) which encouraged the proliferation of endogenous lactobacilli and bifidobacteria. Nonpathogenic Escherichia coli has been shown to protect premature infants from infection. Twenty years later, infants given this E. coli were still found to be less allergic. Meta-analyses have confirmed that Lactobacillus rhamnosus strain GG prevents and treats rotavirus diarrhoea. By reversing the changes in bowel flora which occur with age comes the prospect of rejuvenating ageing immune systems, preventing Clostridium difficile infections and bowel cancer, thereby fulfilling the early promise of prolongation of life.     

高效凝胶渗透色谱法测量发酵液中右旋糖酐的研究

高效凝胶渗透色谱法方便且重现性好,被广泛用于各种多糖分子量及其分布的测量.研究用高效凝胶渗透色谱法直接测量大分子右旋糖酐水解液和发酵液中右旋糖酐.首先,选择出0.7%Na2SO4水溶液(内合0.02%NaN3作流动相,用已知分子量右旋糖酐作标准品,回归获得右旋糖酐分子量与保留时间方程为v=6.6811× 46.511,R2=0.9969.在流速1.0 mL/min,进样量20μL,柱温23℃.检测器温度23℃的色谱条件下,该方程用于测量发酵液中右旋糖酐和某厂家大分子右旋糖酐水解产物,可直接计算出发酵液和水解产物中右旋糖酐分子量及分布.     

纸和纸板挺度剂的研究进展

概述了纸和纸板挺度和环压强度及其影响因素,介绍了挺度剂的原理和对挺度的增强作用;重点分类综述了淀粉类增强剂、聚丙烯酰胺类增强剂、共聚乳液型增强剂及多元复配增强剂对提高环压强度的研究进展,介绍了挺度剂的最新研究成果,并分别阐述了增强机理,最后对环压强度增强剂的发展进行了展望,提出了研究的方向。     

三坐标测量机测试精度的研讨

测量机的制造、安装和调试精度,测头精度,环境条件及其操作人员的技术水准是影响测量机测试精度的主要因素。文中介绍了这些因素对测量精度的具体影响及控制方法。     

Evidence for the strength function of rays in living trees

Subject We investigated the importance of ray tissue for the strength of living beech trees (Fagussylvatica L.). Observations on trees grown under controlled radial tensile loads and technological tests on transverse strengths as well as comparisons among radially stressed parts of trees in nature with control samples indicate that rays are a mechanically functional and adaptive tissue in the transverse plane of living trees.     

Evidence for the strength function of rays in living trees

We investigated the importance of ray tissue for the strength of living beech trees (Fagussylvatica L.). Observations on trees grown under controlled radial tensile loads and technological tests on transverse strengths as well as comparisons among radially stressed parts of trees in nature with control samples indicate that rays are a mechanically functional and adaptive tissue in the transverse plane of living trees.     

面制食品老化程度测定装置的研制

对面制食品的老化程度测定,通常采用质构仪、差示扫描量热法(DSC)、X-射线衍射法、拉曼光谱法、核磁共振光谱法、α-淀粉酶法进行。但该类检测方法存在设备昂贵,需要购置相关检查仪器和药品,对检查人员自身素质要求较高,使用维护成本较高等不足。文章介绍一种面制食品老化程度测定装置,该仪器采用电气化机动控制,能自动测定和记录来自测量现场的数据,克服了上述方法的缺点,集手工操作和机械装置运作于一体,只需进行简单培训即可操作,附属消耗品少,既可满足实验室使用,又可在小规模企业中推广使用。     

Test for measuring the stretchability of melted cheese

A test for measuring the stretchability of cheese was developed by adapting a texture-profile analyzer to pull strands of cheese upwards from a reservoir of melted cheese. Seven different cheeses were analyzed using the Utah State University stretch test. The cheeses were also analyzed for apparent viscosity with a helical viscometer, for meltability using a tube melt test, and for stretch using the pizza-fork test. Cheese was placed into a stainless steel cup and tempered in a water bath at 60, 70, 80, or 90 degrees C for 30 min before analysis. The cup was then placed in a water-jacketed holder mounted on the base of the instrument. A three-pronged hook-shaped probe was lowered into the melted cheese and then pulled vertically until all cheese strands broke or 30 cm was reached. This produced a stretch profile as the probe was lifted through the reservoir of melted cheese and then pulled strands of cheese upwards. Three parameters were defined to characterize the stretchability of the cheese. The maximum load, obtained as the probe was lifted through the cheese, was defined as melt strength (F(M)). The distance to which cheese strands were lifted was defined as stretch length (SL). The load exerted on the probe as the strands of cheese were being stretched was defined as stretch quality (SQ). There was a correlation between F(M) and apparent viscosity. There was also some correlation between SL measured by the fork test and SL when the cheese was tested at 90 degrees C, but no correlation occurred at lower temperatures.