The effect ofDendrolimus superans breakout on growth of trees

The effect ofDendrolimus superans on growth of trees was investigated after the breakout in Shibazhan forest area in 1990. Stem analysis was conducted for determining the tree increment loss. The result showed that the current annual increment for extreme heavily damaged, heavily damaged, moderately damaged and lightly damaged stands is 14%, 39.8%, 64% and 82% of that of the control forest respectively. (Responsible Editor: Chai Ruihai)     

Depletion of ascorbic acid derivatives in fish feed by the production process

ABSTRACT:   The depletion of ascorbic acid derivatives in fish feed during the feed processing (extrusion cooking and drying) was studied at five extrusion cooking temperatures and at 85°C for 2 h dryer processing temperature. Three ascorbic acid derivatives were used: L-ascorbyl-2-mono-phosphate Mg (APM), L-ascorbic acid sodium (AAS) and L-ascorbic acid palmitic acid ester (AAP). Samples were collected after drying and ascorbic acid derivatives losses evaluated. APM was found to be quiet stable with an average retention of 88%, but AAS and AAP were unstable and the depletion was very high.     

分叉角与回转半径对双向流道灌水器水力性能影响模拟研究

为研究双向流道灌水器水力性能，将其结构单元作为研究对象，以分叉角和回转半径两个结构参数为影响因素，采用正交试验设计16种结构参数组合方案，利用计算流体动力学软件Ansysfluent对流道内部流体的流动状态进行数值模拟，通过量纲分析建立流道结构参数与流道单元局部水头损失的回归模型。结果表明：双向流道单元局部水头损失与分叉角、回转半径和流道流速有关，分叉角与局部水头损失呈负相关关系，回转半径和速度与局部水头损失呈正相关关系；当入口流速为固定值时，分叉角为32.4°、回转半径为1.72 mm，流道单元局部水头损失最大；当设置10个流道单元时，交叉排列方式组合的灌水器流态指数较优。     

信阳茶园假眼小绿叶蝉发生特点及危害损失研究

本文通过系统调查研究信阳茶园假眼小绿叶蝉的发生规律,并利用网罩法测定了不同虫口密度对茶叶产量损失的影响。结果表明：假眼小绿叶蝉在信阳地区每年出现2个发生高峰,第1个出现在6月下旬至7月上中旬,第2个出现在9月上中旬;建立了不同虫口密度与产量损失的关系式为Y=0．2303X-0．5026和Y=0．2854X-0．8795（Y-产量损失;X-百叶虫数）。研究结果能为我们制定信阳地区假眼小绿叶蝉的预报预警和防控防治措施提供借鉴。     

Rarity and decline in bumblebees - A test of causes and correlates in the Irish fauna

Bees are believed to be in decline across many of the world’s ecosystems. Recent studies on British bumblebees proposed alternative theories to explain declines. One study suggested that greater dietary specialization among the rarer bumblebee species makes them more susceptible to decline. A second study disputed this theory and found that declines in British bumblebees were correlated with the size of species’ European ranges, leading to the suggestion that climate and habitat specialization may be better indicators of the risk of decline. Here we use a new and independent dataset based on Irish bumblebees to test the generality of these theories. We found that most of the same bumblebee species are declining across the British Isles, but that, within Ireland, a simple food-plant specialization model is inadequate to explain these declines. Furthermore, we found no evidence of a relationship between declines in Irish bumblebees and the size of species’ European ranges. However, we demonstrate that the late emerging species have declined in Ireland (and in Britain), and that these species show a statistically significant westward shift to the extremity of their range, probably as a result of changing land use. Irish data support the finding that rare and declining bumblebees are later nesting species, associated with open grassy habitats. We suggest that the widespread replacement of hay with silage in the agricultural landscape, which results in earlier and more frequent mowing and a reduction in late summer wildflowers, has played a major role in bumblebee declines.     

Effects of wind turbines and other physical elements on field utilization by pink-footed geese (Anser brachyrhynchus): A landscape perspective

The effects of wind turbines and other physical landscape elements on field utilization by wintering pink-footed geese (Anser brachyrhynchus) were studied in a Danish farmland landscape. Within the study area geese were feeding on pastures, which together with cereals were the main crop types. Apart from wind turbines a variety of potentially disturbing landscape elements was present, e.g., high-power lines, windbreaks, roads and settlements. Patterns of field use were assessed by measuring goose dropping densities along transects perpendicular to wind farms (with turbines in clusters and in lines) and other landscape elements. Local effects were expressed in terms of `avoidance distance', i.e., the distance from a given landscape element to the point at which 50% of maximal dropping density was reached. The spatial distribution of landscape elements within an eight km radius from the goose roost was determined from aerial photographs. The area occupied by various elements, together with the adjacent zones which were not available to geese due to their associated avoidance distances, were quantified using Geographic Information System (GIS).The avoidance distance of wind farms with turbines in lines and in clusters were ca 100 m and ca 200 m, respectively. Geese did not enter the area between turbines within the cluster. At the landscape level, the combined effect of physical elements other than wind turbines caused an effective loss of 68% of the total field area (40 km²). Wind turbines caused an additional loss of 4% of the field area. However, of the remaining area available to geese (13 km²), wind turbines caused a loss of 13% of the total area. The habitat loss per turbine was higher for the wind farm with turbines arranged in a large cluster than for wind farms with turbines in small clusters or lines. This difference was mainly due to the fact that wind farms in small clusters or with a linear layout were generally placed close to roads or other elements with existing associated avoidance zones, whereas the large cluster was placed in the open farmland area. The avoidance zones associated with physical elements in the landscape do not take into account possible synergistic effects and, hence, actual field areas affected are likely to be minimum estimates. Implications of these findings for planning of wind farms in areas of conservation interest to geese are discussed.     

香菇渗透脱水工艺优化研究

以新鲜香菇为试材,在单因素试验的基础上,以新鲜香菇失水率和干香菇复水比为考察指标,通过正交试验优化干燥前食盐溶液渗透预处理工艺条件。结果表明,渗透处理最佳工艺条件为:渗透温度30℃,渗透液浓度10%,渗透时间90 min,在此工艺条件,新鲜香菇的失水率为13.9%,干香菇的复水比为4.8。