光肩星天牛和黄斑星天牛杂交研究

在野外对光肩星天牛和黄斑星天牛成虫相互交配进行了调查 ,同时于野外铁纱笼内进行了两种天牛成虫之间的交配试验 .结果表明 ,野外自然条件下两种天牛成虫间都可相互交配 ,其中光肩星天牛♀×♂的比率占34 4 % ,黄斑星天牛♀×♂占 1 3 3% ,淡黄型♀×♂占 1 0 6 % ,黄斑星天牛♀×光肩星天牛♂占 1 6 7% ,光肩星天牛♀×黄斑星天牛♂占 1 0 6 % ,其它类型间的相互交配占 1 4 4 % .铁纱笼内黄斑星天牛♀与光肩星天牛♂交配 ,产生的后代成虫 ,鞘翅表现为白斑、黄斑和淡黄斑 3种类型 ,光肩星天牛♀与黄斑星天牛♂交配后代毛斑为黄斑和淡黄斑 ,黄斑星天牛♀♂交配的后代为淡黄斑和黄斑 .利用这些后代成虫进行再交配试验 ,已得到后代幼虫 1 31头 .根据这些结果及有关两者的生物学、行为学和形态特征观察 ,我们认为它们很可能是一种的不同型     

洞庭湖区植被景观格局数字化图的编绘

为探讨洞庭湖地区的植被景观类型分布特征，采用手持GPS测绘了洞庭湖纯湖区湿地植被景观斑块边界与属性，用分解森林资源分布图上图斑的方法转换周边丘陵低山区植被景观格局的斑块边界与属性，根据景观生态学原理和景观制图要求，采用MapGis软体编绘了洞庭湖区3965957．201hm^2的1：25万植被景观格局数字化图，建立了属性数据库．根据图和数据库分析，洞庭湖地区植被景观具有聚集分布特点z北中部以作物植被和湿地植被景观为主；东南部以油茶林景观为主；西南以楠竹林为主；西面以杉术林景观为主；其他植被景观呈镶嵌状分布．在植被类型景观不同分布区，斑块和底质异质互换．植被景观格局数字化图具有可视、联动、精度高、使用方便等特点．     

Ulvan-Based Nanofibrous Patches Enhance Wound Healing of Skin Trauma Resulting from Cryosurgical Treatment of Keloids

Keloids are skin fibroproliferative disorders, resulting from abnormal healing of deep cutaneous injuries. Cryosurgery, the most common treatment for keloids, causes skin traumas. Even though the clinical practice of cryosurgery has increased, effective wound healing therapy is still lacking. In this investigation, nonwoven nanofibrous patches composed of ulvan, a marine sulfated polysaccharide exhibiting anti-inflammatory and antioxidant activities, and polyethylene oxide (PEO) were fabricated through electrospinning and characterized. Their wound healing efficacy on skin traumas resulting from cryosurgical treatment of keloids was clinically tested and evaluated in comparison to a reference product. Twenty-four volunteer patients undergoing cryosurgery as a treatment of keloids were selected to apply either the ulvan/PEO patch or the reference product for 21 days. The ulvan/PEO patch, 21 days after cryosurgery, showed significant wound healing, elimination of skin inflammation, restoration of biophysical parameters similar to normal values and significant decrease in haemoglobin concentration, skin texture and volume, while no discomfort or adverse reaction was observed. In contrast, the reference product showed inferior performance in all evaluated parameters. The designed ulvan/PEO patch represents the first wound dressing to effectively heal skin trauma after cryosurgical treatment of keloids.     

基于林鸟日常活动范围的郑州金水区景观连通性研究

以郑州市金水区为研究对象,选取了喜鹊、金翅雀、灰椋鸟3种郑州常见林鸟为指标鸟类,利用整体连通性指数、可能连通性指数和绿地斑块对维持连通性的重要值对城市绿地斑块进行了量化分析。结果表明：研究区域内整体的景观连通性水平较低,斑块面积与连通性重要值和可能连通性重要值呈正相关关系,斑块位置会影响绿地斑块的连通性,且“绝对重要”的绿地斑块尺度约为7.7 km²。研究结果可为郑州市绿地资源的建设和调控,及未来动物廊道和入侵物种生境隔离规划提供参考。     

The Epithelium Covering Peyer’s Patches in Young Milk-Fed Calves: An Ultrastructural and Enzyme Histochemical Investigation

Between the ordinary villi over Peyer’s patches there are small domes or “pseudovilli” caused by bulges in the lymphoid tissue. These “pseudovilli” were studied in 5 healthy milk-fed, about 3-week-old, pre-ruminant calves. Scanning electron microscopy revealed that the “pseudovilli” were covered by a specialized follicle associated epithelium (FAE). The FAE had poorly developed microvilli and often extensive folding of the cell surface close to the cell borders. By transmission electron microscopy the tips of the marginal folds of the FAE seemed to fuse, probably in the process of enfolding bulk material from the lumen. The FAE apical cytoplasm contained numerous thick-walled and bristle-coated invaginations, tubules and vesicles indicative of micropinocytosis. Multivesicular bodies and large vacuoles were frequent. Indications of extracellular unloading of residual bodies were found. Intraepithelial lymphocytes tended to group together, and some were rich in rough endoplasmic reticulum. Enzyme histochemistry showed weak reactions of adenosine triphosphate splitting enzyme and aminopeptidase in the FAE luminal cell border. Cytoplasmic acid phosrphatase showed a marked basal-apical decrease along the “pseudovillus” probably caused by the onset of endocytosis. The results of this study appear compatible with the concept that the FAE takes up macromolecules from the lumen by pinocytosis and sensitizes lymphocytes.     

服从Gompertz增长的两斑块种群模型及其定性分析

为研究同一个种群分布在保护区和非保护区两个不同的斑块环境中的生长情况,建立种群密度服从Gompertz增长的生物模型。分别应用微分方程理论和数学软件对模型进行定性分析和数值分析,得到模型有唯一的稳定的正规结点。即两个斑块内的种群密度随着时间的增长,最终会稳定在一个固定值。同时讨论斑块间不存在迁移和努力度逐渐增大时的两斑块内种群的密度情况。结果表明：若不存在斑块间的迁移,保护区斑块内种群密度将会达到最大环境容量,而非保护区斑块内种群密度将趋于稳定;随着努力度的增加,会出现过度捕捞,最终导致非保护区斑块内的种群趋于灭亡。     

The composition of the soil seedbank and its role in ecosystem dynamics and rehabilitation potential in the arid Tankwa Karoo Region,South Africa§

Very few soil seedbank studies have been conducted in South Africa, especially in arid rangelands. Insight into the soil seedbank could therefore improve assessment of rangeland dynamics and enhance rehabilitation efforts. This study aimed to characterise the soil seedbanks in various vegetation types of the Tankwa Karoo National Park, an arid environment in South Africa. At 43 sites soil was sampled twice at the end of spring and the end of autumn, and the composition and structure of aboveground vegetation were described at the peak growth period in spring. Seeds were isolated from the soil samples by means of flotation in a salt solution, seedbank species composition was obtained by seedling germination, and the vegetation was investigated using a line-point survey method. Overall seed density was 8 034 seeds m^?2 of which 55% was viable, and the common life-forms were therophytes and chamaephytes. Species richness and diversity were lower in the seedbank compared with those of the vegetation, and the two vegetation spheres were 25% similar. While seedbank composition suggested poor veld condition, there was enough seed density and viability for future regeneration and rehabilitation initiatives. However, this may be impeded by the absence of many perennial species in the soil seedbank.     

基于灌木层植物多样性的森林景观斑块耦合网络研究

为了研究西洞庭湖区的森林景观格局及其对灌木层植物多样性的影响,笔者根据西洞庭湖区森林分布,将景观分成12类,通过合并地理位置相邻的同类小班构成景观斑块,利用Shannon-Wiener指数推导出斑块间灌木层边缘效应大小作为边权,建立斑块耦合网络模型,并构建基于灌木层的景观斑块耦合网络。结果表明：景观斑块耦合网络中节点的度呈幂率分布,具有无标度网络和小世界网络特征;节点的度与介数之间满足正相关高阶曲线关系,表明度越大的节点在网络连通中的重要程度越大;林龄大的景观网络,其密度与聚集系数相对较大,网络稳定性越强;从常德林场景观网络中得知,尽管基于灌木层的斑块网络中,单个节点的点强度有正有负,但整个网络的点强度总体呈正值,这种景观格局分布有利于灌木层植物多样性的提高。     

Beyond patch spraying: site-specific weed management with several herbicides

Site-specific weed management can include both limiting herbicide application to areas of the field where weed pressure is above the economic threshold (patch spraying) and varying the choice of herbicide for most cost-effective weed control of local populations. The benefits of patch spraying with several, postemergence herbicides in irrigated corn were evaluated in simulation studies using weed counts from 16 fields. Patch spraying with one, two or the number of herbicides that maximized net return for a field was simulated. With patch spraying of one herbicide, the average area of a field left untreated is 34.5%. Net return increases by $3.09 ha⁻¹ compared to a uniform application without decreasing crop yield. Additional herbicides increase the average benefits with just 4% more of the field treated. With two herbicides, the increase in net return is almost tripled and herbicide use is reduced nearly 10-fold compared to patch spraying with one herbicide, and weed control is better than the uniform application in 10 fields. Using more than two herbicides for patch spraying further reduces weed escapes, but herbicide use is greater than a uniform application in 10 fields. Growers might be more willing to adopt patch spraying if more than one herbicide is used in a field.     

Site-specific weed control technologies

Site-specific weed control technologies are defined as machinery or equipment embedded with technologies that detect weeds growing in a crop and, taking into account predefined factors such as economics, take action to maximise the chances of successfully controlling them. In this study, we describe the basic parts of site-specific weed control technologies, comprising weed sensing systems, weed management models and precision weed control implements. A review of state-of-the-art technologies shows that several weed sensing systems and precision implements have been developed over the last two decades, although barriers prevent their breakthrough. Most important among these is the lack of a truly robust weed recognition method, owing to mutual shading among plants and limitations in the capacity of highly accurate spraying and weeding apparatus. Another barrier is the lack of knowledge about the economic and environmental potential for increasing the resolution of weed control. The integration of site-specific information on weed distribution, weed species composition and density and the effect on crop yield, is decisive for successful site-specific weed management.