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41.
Importance of an appropriate visual presentation for avoiding a misconception of the menstrual cycle
Family planning, the prevention of unwanted pregnancy, and women’s reproductive health are topics that have received close attention for decades. It would therefore be fair to assume that there exists a good knowledge of the menstrual cycle. However, it is clear that many people have various misconceptions about the menstrual cycle and fertile days or ovulation, and that this process is still largely taught with the aid of materials and images that have not changed for many years. We investigated the effect of moving away from the usual teaching practice of using a 28-day diagram showing ovulation on the 14th day. A total of 184 students from three different high schools, aged between 17 and 18, participated in this research. The students who were taught using three diagrams showing different durations of the menstrual cycle showed a significantly better adoption of the facts and concepts compared to the students who were taught using a diagram of the average 28-day cycle. Our results confirmed that it is highly important to use appropriate visual displays in the teaching of the menstrual cycle and that it is essential to enhance the visual literacy of students and teachers. 相似文献
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Modeling urban landscape dynamics: A review 总被引:5,自引:0,他引:5
Reviewed here is the historical development of urban growth models, showing how different disciplines and diverse theories have come together over time to produce the models used today. This review is divided into two sections, the first section reviews the early models that are rooted in transportation and land-use planning and form the foundation on which nearly all modeling efforts are based. These models are already well documented in the literature and an overview here is sufficient. In the second section, an exploration is made into the theories and approaches that have been integrated into urban modeling efforts. The concepts are outlined and one or more contemporary examples are highlighted. These theories and approaches represent the major areas of development that exist in published work. 相似文献
45.
城市生态规划的回顾与展望 总被引:20,自引:2,他引:18
回顾了城市生态规划的发展情况,对其发展前景进行了展望。从19世纪末至今,从Howard的“田园城市”到MacHarg的土地利用生态规划方法,再到基于生态系统理论的城市生态对策规划,城市生态规划的理论和方法在实践中不断完善。全球城市化进程的加快带来了一系列的生态环境问题。城市生态规划作为实现城市可持续发展的途径之一,越来越受到人们的关注,为生态城市建设服务是城市生态规划的发展方向。 相似文献
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Jessica?Lagerstedtkth.se" title="jessica@md kth.se" itemprop="email" data-track="click" data-track-action="Email author" data-track-label="">Email author Conrad?Luttropp Lars-Gunnar?Lindfors 《The International Journal of Life Cycle Assessment》2003,8(3):160-166
Aim, Scope and Background The interest in environmental questions has increased enormously during the last decade. Environmental protection has become
an issue of strategic importance within the manufacturing industry and many companies are now working in the field of Design
for Environment (DFE). The main purpose of DFE is to create products and services for achieving a sustainable society. Designers
are widely believed to have a key role in adapting products to a sustainable society and one of the major instruments in the
context of Design for Environment is Life Cycle Assessment (LCA). However, product development creates particular challenges
for incorporating environmental issues that combine functional and environmental assessment. A natural and important part
of product design is to define and analyse the functions of the product. Consequently, the functional unit in LCA is a core
issue in DFE. Most recent research in DFE has focused on how to reduce the environmental impact of products throughout their
life-cycle by addressing environmental aspects, while little attention has been given to the functionality of the product.
Additionally, early product development phases, so called re-think phases, are considered to have the influence on major changes
in products in general. These phases have thus the highest potential for changing products and product systems towards a sustainable
development.
Main Features This paper discusses an extended functional representation in design for environment methods to evaluate sustainable design
solutions, especially in early (re-think) phases of product design. Based on engineering-design science and several case studies,
a concept has been developed describing how functional preferences can be visualised in design for environment and product
development. In addition, the functional unit in LCA is discussed. The concept is called Functional Profile (FP) and is additionally
exemplified in a case study on radio equipment.
Discussion The new functional characterisation concept helps identify functional priorities in design for environment. The Functional
Profile is a structured, systematic and creative concept for identifying the necessary functions of a new product. The FP
is envisioned to complement existing design for environment methods, not to replace them. Instead of being a product-development
tool or method, the concept is an approach that increases understanding of inter-reactions between functional characteristics
of products and their environmental characteristics, which furthermore facilitates trade-off decisions. One of the objectives
behind the concept is to highlight the importance of balancing functional requirements and environmental impacts, presenting
both the advantages and disadvantages of the product.
Outlook A second paper will be produced to complement the functional-environmental characterisation concept in early product development
phase, presenting the environmental characterisation part and illustrating correlations between the functional and environmental
sides. 相似文献
47.
Clustering Timber Harvests and the Effect of Dynamic Forest Management Policy on Forest Fragmentation 总被引:1,自引:1,他引:0
Eric J. Gustafson 《Ecosystems》1998,1(5):484-492
To integrate multiple uses (mature forest and commodity production) better on forested lands, timber management strategies
that cluster harvests have been proposed. One such approach clusters harvest activity in space and time, and rotates timber
production zones across the landscape with a long temporal period (dynamic zoning). Dynamic zoning has been shown to increase timber production and reduce forest fragmentation by segregating uses in time without reducing the spatial extent of timber production. It is reasonable
to wonder what the effect of periodic interruptions in the implementation of such as strategy might be, as would be expected
in a dynamic political environment. To answer these questions, I used a timber harvest simulation model (HARVEST) to simulate
a dynamic zoning harvest strategy that was periodically interrupted by changes in the spatial dispersion of harvests, by changes
in timber production levels, or both. The temporal scale (period) of these interruptions had impacts related to the rate at
which the forest achieved canopy closure after harvest. Spatial dynamics in harvest policies had a greater effect on the amount
of forest interior and edge than did dynamics in harvest intensity. The periodically clustered scenarios always produced greater amounts of forest interior and less forest edge than did their never clustered counterparts. The results suggest that clustering of harvests produces less forest fragmentation than dispersed cutting alternatives,
even in the face of a dynamic policy future. Although periodic episodes of dispersed cutting increased fragmentation, average
and maximum fragmentation measures were less than if clustered harvest strategies were never implemented. Clustering may also
be useful to mitigate the fragmentation effects of socially mandated increases in timber harvest levels. Implementation of
spatial clustering during periods of high timber harvest rates reduced the variation in forest interior and edge through time,
providing a more stable supply of forest interior habitat across the landscape.
Received 19 September 1997; accepted 6 August 1998. 相似文献
48.
Antje Burke 《Journal of Biogeography》2004,31(10):1613-1622
Aim This study investigated spatial patterns of endemism in the flora of Namibia's succulent karoo in order to generate information for conservation planning. Location The study area, the Sperrgebiet, comprises the majority of Namibia's portion of the succulent karoo biome which is the south‐west corner of the country. This is an arid area that has been off limits to public access, farming and tourism for nearly a century due to restrictions imposed by the diamond industry. Methods Based on existing distribution records, areas of high concentrations of endemic plants were identified using numbers of endemics and weighted endemics according to area of occupancy. The resolution of the available data was quarter degree squares (15‐min intervals of latitude and longitude grids). Results At the scale of this study straight numbers of endemics generated similar results to the endemics weighted according to area of occupancy, which gives sparsely distributed species a higher weighting. Based on the current distribution records, 17.7% (184 species) of the Sperrgebiet's spermatophyte flora is endemic. The ‘hotspots of endemism’ comprised from north to south: Lüderitz‐Kowisberge, Klinghardt Mountains, Aurusberge‐Heioab, Witpütz, Skorpion and Obib‐Schakalsberge. Taking also areas into account that stand out because of their high proportion of local endemics, this adds Grillental and the central coastal area from Pomona to Baker's Bay to the areas of importance for plant endemism. Main conclusions The Sperrgebiet's endemic flora is special in taxonomic composition in that it does not present a subset of the total flora of this area, but shows a remarkably high representation of the families Mesembryanthemaceae and Liliaceae (sensu lato). Compared with other arid areas, the level of endemism in the Sperrgebiet is high, but not compared with the succulent karoo in general or other hotspots in the succulent karoo biome, such as the Richtersveld. The proportion of local endemics (13.5%) is high compared with some endemism hotspots in southern Africa. Hotspots of plant endemism provide an important tool to contribute to conservation planning studies. This study also highlighted the importance of centralized data bases without which these analyses would not have been possible. Further plant collecting is required to fill presently data‐deficient areas and studies at a finer spatial resolution taking habitat requirements into account are needed to elucidate some of the factors contributing to plant endemism in this area. 相似文献
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Predicted avian responses to bioenergy development scenarios in an intensive agricultural landscape 下载免费PDF全文
Daniel R. Uden Craig R. Allen Rob B. Mitchell Tim D. McCoy Qingfeng Guan 《Global Change Biology Bioenergy》2015,7(4):717-726
Conversion of native prairie to agriculture has increased food and bioenergy production but decreased wildlife habitat. However, enrollment of highly erodible cropland in conservation programs has compensated for some grassland loss. In the future, climate change and production of second-generation perennial biofuel crops could further transform agricultural landscapes and increase or decrease grassland area. Switchgrass (Panicum virgatum) is an alternative biofuel feedstock that may be economically and environmentally superior to maize (Zea mays) grain for ethanol production on marginally productive lands. Switchgrass could benefit farmers economically and increase grassland area, but there is uncertainty as to how conversions between rowcrops, switchgrass monocultures and conservation grasslands might occur and affect wildlife. To explore potential impacts on grassland birds, we developed four agricultural land-use change scenarios for an intensively cultivated landscape, each driven by potential future climatic changes and ensuing irrigation limitations, ethanol demand, commodity prices, and continuation of a conservation program. For each scenario, we calculated changes in area for landcover classes and predicted changes in grassland bird abundances. Overall, birds responded positively to the replacement of rowcrops with switchgrass and negatively to the conversion of conservation grasslands to switchgrass or rowcrops. Landscape context and interactions between climate, crop water use, and irrigation availability could influence future land-use, and subsequently, avian habitat quality and quantity. Switchgrass is likely to provide higher quality avian habitat than rowcrops but lower quality habitat than conservation grasslands, and therefore, may most benefit birds in heavily cultivated, irrigation dependent landscapes under warmer and drier conditions, where economic profitability may also encourage conversions to drought tolerant bioenergy feedstocks. 相似文献