COMPARISON OF ISODOSE DISTRIBUTIONS IN CANINE BRAIN IN HETEROGENEITY-CORRECTED VERSUS UNCORRECTED TREATMENT PLANS USING 6 MV PHOTONS

Magnetic resonance (MR) images may be useful for radiation planning due to greater contrast resolution. One disadvantage of MR images for radiation planning is the inability to incorporate electron density information into the dose calculation algorithm. To assess the magnitude of this problem, we evaluated radiation dose distribution in canine brain by comparing computed tomography (CT)-based radiotherapy plans with and without electron density correction. Computerized radiotherapy plans were generated for 13 dogs with brain tumors using 6 MV photons. A tissue-contouring program was used to outline the gross tumor volume (GTV) and the planning target volume (PTV) for each patient. Two treatment plans were generated for each dog. First, the plan was optimized without heterogeneity correction. Then the heterogeneity correction was implemented without changing any other plan parameters. Isodose distributions and dose volume histograms (DVHs) were used to compare the two plans. The D95 (dose delivered to 95% of the volume) within the PTV was calculated for each treatment plan and differences in the D95s were compared. The mean D95s without and with heterogeneity correction were 49.1 +/- 0.7 and 48.9 +/- 1.0Gy, respectively. The absolute mean percent dose difference without and with heterogeneity correction was 1.0 - 0.9% (-1.3-3.2%) and was not considered to be clinically significant. We found no clinically significant difference between CT-based radiotherapy plans without and with heterogeneity correction for brain tumors in small animals, which supports the use of MR-based treatment planning for radiotherapy of small animal brain tumors.     

新世纪保护区面临的挑战及其有效对策

道路、水库、建筑物、不断扩大的农田和土地退化正在使自然景观的完整性受到严重破坏。所保存的未经干扰或少受干扰的天然生态系统的面积日益缩小，犹如海洋中的孤岛。生物多样性受到严重的威胁。在自然保护区中，物种迁移和基因流动的可能性也在不断地降低。生物区域规划被认为是一种较好的选择，它力求把保护区和栽培地区视为一个有机整体，遵循保护和发展密切结合的方针，制定行动计划并予以实施。本文根据保护区的管理情况、工作条件和科研状况等，对保护区或区域的类型进行了划分，针对现实，提出了如何实施生物区域规划。     

Promoting and preserving biodiversity in the urban forest

Efforts at mitigating global biodiversity loss have often focused on preserving large, intact natural habitats. However, preserving biodiversity should also be an important goal in the urban environment, especially in highly urbanized areas where little natural habitat remains. Increasingly, research at the city/county scale as well as at the landscape scale reveals that urban areas can contain relatively high levels of biodiversity. Important percentages of species found in the surrounding natural habitat, including endangered species, have been found in the urban forest.

This contribution concisely highlights some examples of urban biodiversity research from various areas of the world. Key issues involved in understanding the patterns and processes that affect urban biodiversity, such as the urban–rural gradient and biotic homogenization, are addressed. The potential for urban areas to harbor considerable amounts of biodiversity needs to be recognized by city planners and urban foresters so that management practices that preserve and promote that diversity can be pursued. Management options should focus on increasing biodiversity in all aspects of the urban forest, from street trees to urban parks and woodlots.     

Urban forests as compensation measures for infrastructure development

Sustainable development requires, among other things, that development projects not result in the degradation of natural resources for outdoor recreation. There has been a rapid increase in knowledge regarding the importance of the external environment to our health and well-being. Stress is reduced significantly when people are exposed to health-promoting nature and landscape values. Many people are actively choosing to reduce their stress. Doctors today prescribe outdoor walks in peaceful environments for the same purpose. A high level of traffic noise increases stress. This paper discusses the application of silent values in an infrastructure development project, the extension of Sturup Airport, east of Malmö, Sweden and Copenhagen, Denmark. Through estimating the change in noise resulting from the development, it is possible to integrate mitigating and compensating measures in the planning process discussions. Such measures can be negotiated as conditions for authorization of the project. The airport is situated in an area rich in nature values for recreation. The airport expansion will mean both new noise impacting "silent" areas and increasing noise levels in already noise-affected areas. In this study, we have taken a positive stand on the silent areas, mostly agriculture land, where compensation measures could be taken, thus balancing the loss of silent nature values for recreation. Silent areas that will not be affected are suitable and feassible for compensation measures thus can be called compensation areas. In this way the development of new recreational areas, preferably designed as urban forests, are critical preconditions for the negotiations for the airport extension. The conclusion is that urban forest investments for health and well-being can be an important part of strategic decisions in spatial planning. As preconditions for a permit, the development and financing of new urban forests and green areas can be part of the total development plan. This is an issue of global interest, as many countries are in a process of rapid urbanization, and urban greening and urban forestry have an important role to play in the process of promoting quality of life and improving environmental quality.     

青岛梅园的建设及梅花品种的搜集与选育

在简介青岛梅园这一北方“新星”后，着重报道了其在建园中完成的两项科研成果，即①梅园快速规划设计与施工；②梅花品种的搜集、整理与新品种选育     

论一体化管理的国土整治规划思想——以重庆市璧山县大路镇国土整治规划为例

研究目的：为科学编制镇级国土整治规划提供理论依据，为同类研究提供参考。研究方法：文献研究、理论研究、实证研究。研究结果：国土整治规划必须贯彻一体化管理思想；提出一体化管理国土整治规划思想的含义、特征及辩证关系。研究结论：一体化管理的国土整治规划思想是指导镇级国土整治行动及规划编制行之有效的思想。     

基于生态-形态-心态整合设计的高校校园环境优化策略研究

剖析当前我国高校校园环境建设中存在的问题，以问题为指向，深入探究基于“生态-形态-心态”整合设计的高校校园环境优化策略，使教育育人和环境建设二者有机结合，以求为我国正在快速发展的高等教育和校园建设提供指导和借鉴。     

在林业计算机制图中运用FontCreator软件制作点状图符号的方法

以LY／T2009—2012（（县级林地保护利用规划制图规范》中所示的点状符号制作为例，从创建符号文件、添加编辑符号文件、保存安装符号文件、使用符号文件等方面阐述FontCreator软件在地图符号制作中的应用，认为FontCreator软件制作专题图符简便、快捷，图符清晰规范，符合要求。     

城郊型观光农业园区可持续规划研究——以扬州市沙头镇观光农业园区为例

以城郊型观光农业园区的特征为切入点,分析当前我国观光农业的发展与园区规划存在的问题,进而提出观光农业园区规划应该引入可持续发展的思想,运用生态规划的手法进行可持续规划,规划内容主要包括以农业产业为核心的农业产业发展规划和以土地利用为核心的修建性规划。并以扬州市沙头镇观光农业园区为例,探讨城郊型观光农业园区可持续规划的理论与实践的方法,以期为该类观光农业园区规划提供借鉴。     

合理规划布局 巧设园林空间

园林空间是一种艺术空间，是园林设计的关键。而设计手法是空间布置、平面构图、合理造园的重要手段。介绍了南海桂城平洲广场的设计构思，阐明了现代园林规划中的设计手法与空间布局技巧。