黄土高原地区长期施用微肥土壤Cu、Zn、Mn、Fe含量的时空变化

以19年微肥定位试验为基础,研究了长期施用微肥条件下冬小麦土壤Cu、Zn、Mn、Fe含量的时空变化。结果表明,长期施用微肥能增加土壤耕层相应微量元素含量,施铜肥的土壤耕层有效Cu含量增加5倍以上;施锌肥的土壤耕层有效Zn含量增加3.58倍。从剖面变化看,不同处理土壤有效Cu的变化趋势一致,且耕层以下各土层有效Cu含量低于耕层,土壤有效Zn的变化趋势与之相似;土壤有效Mn在80cm土层含量较高,80cm以上以及下面的土层中Mn含量明显低于80cm土层,在土壤剖面上有效Mn存在淋溶和累积现象。施用不同微肥对土壤有效Fe含量的影响各不相同。     

Effect of body position on the arterial partial pressures of oxygen and carbon dioxide in spontaneously breathing,conscious dogs in an intensive care unit

Objective – To evaluate the effect of body position on the arterial partial pressures of oxygen and carbon dioxide (PaO₂, PaCO₂), and the efficiency of pulmonary oxygen uptake as estimated by alveolar‐arterial oxygen difference (A‐a difference). Design – Prospective, randomized, crossover study. Setting – University teaching hospital, intensive care unit. Animals – Twenty‐one spontaneously breathing, conscious, canine patients with arterial catheters placed as part of their management strategy. Interventions – Patients were placed randomly into lateral or sternal recumbency. PaO₂ and PaCO₂ were measured after 15 minutes in this position. Patients were then repositioned into the opposite position and after 15 minutes the parameters were remeasured. Measurements and Main Results – Results presented as median (interquartile range). PaO₂ was significantly higher (P=0.001) when patients were positioned in sternal, 91.2 mm Hg (86.0–96.1 mm Hg), compared with lateral recumbency, 86.4 mm Hg (73.9–90.9 mm Hg). The median change was 5.4 mm Hg (1.1–17.9 mm Hg). All 7 dogs with a PaO₂<80 mm Hg in lateral recumbency had improved arterial oxygenation in sternal recumbency, median increase 17.4 mm Hg with a range of 3.8–29.7 mm Hg. PaCO₂ levels when patients were in sternal recumbency, 30.5 mm Hg (27.3–32.7 mm Hg) were not significantly different from those in lateral recumbency, 32.2 mm Hg (28.3–36.0 mm Hg) (P=0.07). The median change was ?1.9 mm Hg (?3.6–0.77 mm Hg). A‐a differences were significantly lower (P=0.005) when patients were positioned in sternal recumbency, 21.7 mm Hg (17.3–27.7 mm Hg), compared with lateral recumbency, 24.6 mm Hg (20.4–36.3 mm Hg). The median change was ?3.1 mm Hg (?14.6–0.9 mm Hg). Conclusions – PaO₂ was significantly higher when animals were positioned in sternal recumbency compared with lateral recumbency, predominantly due to improved pulmonary oxygen uptake (decreased A‐a difference) rather than increased alveolar ventilation (decreased PaCO₂). Patients with hypoxemia (defined as PaO₂<80 mm Hg) in lateral recumbency may benefit from being placed in sternal recumbency. Sternal recumbency is recommended to improve oxygenation in hypoxemic patients.     

Impact of rank position on fertility of sows

The investigations were carried out with 484 sows from two farms (farm A: housing the sows in small groups of 8 animals each, farm B with a large group of 100 sows) and a total number of 982 inseminations. The number of agonistic interactions was registered for each sow during 48 h after mixing soon after weaning the piglets at farm A. The individual rank place in the social hierarchy was calculated on the basis of wins and defeats and the sows were divided in high and low ranking sows. At farm B the rank position was estimated on the basis of the daily feeding order at two electronic feeding stations (first half of the sows in the feeding order = high ranking, second half = low ranking). Additionally, the following parameters were recorded for each sow: parity, genotype, farrowing rate and litter size (total and alive born piglets). The analysis showed that sows with a high rank position had a significantly higher farrowing rate (88.8%) compared to group-mates with low rank places (82.8%, p = 0.051) (farm A). Sows with a high rank position reached a significantly higher litter size of total born piglets (12.66, 16.14 piglets per litter respectively) than the low-ranking group-mates (12.13, 14.83 piglets/litter respectively — farms A and B). When mixing sows, the time and the conditions (e.g. group size, space allowance per sow) have to be considered to prevent the negative influence of low rank order on fertility.     

坡位对小叶杨人工林生长及土壤养分空间差异的影响

选择毛乌素地区东北部梁地上3种类型的小叶杨人工林,研究了坡位对其生长和土壤养分空间差异的影响。结果表明:整体上,坡位对小叶杨和沙柳的生长均有显著影响。小叶杨人工林植被生长均表现为:坡底>坡顶≥坡中,小叶杨和柠条的混交林比其他两个林型生长好。小叶杨人工林土壤有机质含量在坡底部位多数土层中含量较高,在0.57%~1.09%之间,坡中和坡顶部位含量较小,分别在0.36%~1.07%和0.32%~0.82%之间,这与植被生长较好密切相关;土壤有机质含量在不同坡位均呈波动式减少的趋势,0~10 cm土层中含量均最大,在0.63%~1.09%之间。坡中部位各土层中的速效N、速效P和速效K含量较高,分别在18.82~66.63 m g/kg,24.07~90.06 m g/kg和51.94~190.24 m g/kg,这与坡中植被生长较差有关;而坡底和坡顶较小,速效N、速效P和速效K在不同坡位垂直变化趋势差异较大。另外,小叶杨和柠条混交林的土壤平均养分含量均较高,土壤有机质0.81%,速效N 33.84 m g/kg,速效P 49.03 m g/kg,速效K 104.14 m g/kg。     

基于CT扫描研究青海湖流域高寒草甸不同坡位土壤大孔隙结构特征

以青海湖流域的高寒草甸土壤为研究对象,对该高寒草甸的坡上、坡中和坡下土壤分别取原状土柱进行CT扫描,利用Fiji软件分析土壤大孔隙结构特征的差异。结果表明:坡位对土壤的大孔隙结构有较大影响,坡上土壤的大孔隙数量、大孔隙度和大孔隙等效直径均大于坡中土壤,坡中土壤的大孔隙参数大于坡下土壤,坡上土壤的平均大孔隙度是坡中和坡下土壤的15.5和46.5倍。坡上土壤的大孔隙主要分布在150~400 mm土层深度,而坡中土壤的大孔隙主要分布在0~150 mm深度,坡下土壤的大孔隙主要在0~200 mm深度分布。坡上和坡中土壤的大孔隙形成主要是在土壤团聚体的作用下形成,植物根系在坡下土壤的大孔隙形成中占主导作用。     

深化图书馆改革是增强文化活力的重要基石———初论图书馆事业在新时期国家发展中的战略地位

建设社会主义文化强国，关键是增强全民族的文化活力。为增强文化活力，就要深化文化体制改革，解放和发展文化生产力，发扬学术民主，艺术民主，为人民提供广阔文化舞台，让一切文化创造源泉充分涌流。而全面深化图书馆改革就属于深化文化体制改革这一战略规划的重要组成部分．具有不容忽视的战略地位，它必将为增强中华民族的文化活力、建设文化强国做出自身应有的贡献。     

自走式亚麻脱粒翻铺机的脱粒机构

详细阐述了自走式亚麻脱粒翻铺机脱粒机构的结构和工作原理,通过建立1:1的实验模型验证了亚麻脱粒装置的旋转速度,进而确定设计的主要技术参数,并对该机构的位置关系进行了理论分析和计算。根据主要技术参数,设计出脱粒机构的主要部件—脱粒锥辊和压麻辊,并确定出锥辊变速箱的传动比及具体结构,完成主要部件的布局和设计。制作样机后与现有的多种亚麻脱粒机进行了对比实验,并对实验结果汇总分析,最后得出该脱粒机构是一种新型的、先进的脱粒装置这一结论。     

不同坡向杉木3代种子园土壤有效养分差异比较分析

以杉木3代种子园为研究对象,分析不同坡向杉木3代种子园土壤有效养分含量差异,从而为实现杉木种子园的合理施肥奠定理论基础。研究结果表明,同一坡向随着坡位上升以及同一坡位随着土层深度的增加,杉木3代种子园土壤有效养分含量呈逐渐下降趋势;同一坡位同一土层深度不同坡向对土壤有效养分含量的影响体现出较为复杂的规律。     

Longitudinal variation in fish species composition in the Angabanga river, Papua New Guinea with observations on the trophic status of certain fish species

Abstract– Longitudinal variation in fish species composition at various sites on the Angabanga river showed an increase in diversity from source to mouth and that only a few fish species occur at all sites. The fish assemblage of floodplain pool areas contained fewer species than the main channel and was dominated by two exotic species Oreochrornis mossambicus (Peters 1852) and Trichoguster pectoralis (Regan 1910). Most native fish species utilize invertebrates as a food source. The absence of indigenous detritus/substrate feeders in the Angabanga community may account in part for the success of the two introduced species on the floodplain.     

浅析坡向、坡度、坡位对卫片色调的影响

文章以大兴安岭地区图强林业局 1999年森林资源二类调查成果为依据 ,探讨了坡向、坡度、坡位对卫片色调的影响 ,有助于建立目视解译标志 ,进行目视判读。从而减少林业调查外业工作量 ,降低成本 ,提高林业调查速度 ,缩短林业调查周期