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11.
C. Kenneth Waters 《Biology & philosophy》1998,13(1):5-36
Former discussions of biological generalizations have focused on the question of whether there are universal laws of biology. These discussions typically analyzed generalizations out of their investigative and explanatory contexts and concluded that whatever biological generalizations are, they are not universal laws. The aim of this paper is to explain what biological generalizations are by shifting attention towards the contexts in which they are drawn. I argue that within the context of any particular biological explanation or investigation, biologists employ two types of generations. One type identifies causal regularities exhibited by particular kinds of biological entities. The other type identifies how these entities are distributed in the biological world. 相似文献
12.
为把握森林不同深度的土壤温度对区域气候变暖的响应,评估气候变暖对亚热带森林土壤呼吸的影响,利用在哀牢山亚热带常绿阔叶林中设置的土壤增温和土壤呼吸人工控制实验,对2011—2013年的对照样地和增温样地不同深度的土壤温度实测数据进行了分析,结果表明:区域气候变暖导致的温度升高不改变土壤温度的年变化和日变化特征;干季的增温效应大于雨季;同一深度增温效应具有一定的年变化,但日变化不明显;增温效应在土壤表层较大,1—4月明显,2月最高,增温可达3℃;5 cm深度的平均增温效应在2℃左右,且年变化较小;随着深度的增加,增温效应呈现对数降低趋势;如果以0.5℃为增温效应的阈值,推算可得出:干季的影响深度为3.82 m,雨季可达12.04 m,年均为6.58 m。 相似文献
13.
Habitat destruction is driving biodiversity loss in remaining ecosystems, and ecosystem functioning and services often directly depend on biodiversity. Thus, biodiversity loss is likely creating an ecosystem service debt: a gradual loss of biodiversity‐dependent benefits that people obtain from remaining fragments of natural ecosystems. Here, we develop an approach for quantifying ecosystem service debts, and illustrate its use to estimate how one anthropogenic driver, habitat destruction, could indirectly diminish one ecosystem service, carbon storage, by creating an extinction debt. We estimate that c. 2–21 Pg C could be gradually emitted globally in remaining ecosystem fragments because of plant species loss caused by nearby habitat destruction. The wide range for this estimate reflects substantial uncertainties in how many plant species will be lost, how much species loss will impact ecosystem functioning and whether plant species loss will decrease soil carbon. Our exploratory analysis suggests that biodiversity‐dependent ecosystem service debts can be globally substantial, even when locally small, if they occur diffusely across vast areas of remaining ecosystems. There is substantial value in conserving not only the quantity (area), but also the quality (biodiversity) of natural ecosystems for the sustainable provision of ecosystem services. 相似文献
14.
The concept of risk-adapted therapy in lymphoma is increasingly accepted as a way to achieve higher cure rates with a lower or equal risk of treatment-related morbidity and mortality. Tailoring and individualizing therapy according to the need of the patient is a therapeutic option which could maybe soon become the standard of care. However, it is still not proven that modifying therapy based on interim-PET can improve patient outcomes. Therefore, this issue must be analyzed in appropriately designed clinical trials. 18F-FDG PET enables evaluation of the early metabolic changes rather than the morphologic changes which occur later during therapy. In lymphoma these early metabolic changes are highly predictive of the final treatment response. PET performed after a few courses of standard chemotherapy is a reliable prognostic tool to identify poor responders to therapy. Interim-PET is a powerful prognostic tool when compared to other well-established clinical parameters in lymphoma. However, the major drawback in the literature appeared to be related to the lack of uniform and reliable criteria for interim-PET scan interpretation. Therefore, in April 2009 an international meeting took place in Deauville (France), where uniform criteria were established for interim-PET scan interpretation. On the other hand, when PET is used to assess treatment response after completion of therapy, the criteria established in the International Harmonization Project in 2007 must be applied. These recommendations were designed to standardize the interpretation of interim PET and PET at the conclusion of therapy of patients with lymphoma both in clinical practice and clinical trials. 相似文献
15.
N. Yeni M. Vermandel D. Huglo A. BéronS. Adib G. LionA.-S. Dewalle-Vignion 《Médecine Nucléaire》2011,35(3):146-155
Objective
Set up a framework for evaluating automatic segmentation methods of tumour volumes on PET images.Patient and methods
This study was performed with PET images of 18 patients with non-Hodgkin's lymphoma. One target lesion per patient was pointed out. Each lesion was then three times manually delineated by five experts. Four automatic methods (the application of a threshold of 42% of the maximum SUV, the MIP-based method, the Daisne et al. method and the Nestle et al. method) were evaluated by comparison with the set of manual delineations.Results
From the manual delineations, we have concluded to a moderate intra-operator variability and to a reduced interoperator reproducibility. From statistical tests performed on various quantitative criteria, there was no significant difference between the MIP-based method, the Daisne et al. method and the Nestle et al. one. The application of a threshold of 42% of the maximum SUV appears to be less efficient.Conclusion
This work proposes a comparison and an evaluation protocol for segmentation methods. The generated data set will be distributed online for the community to simplify the evaluation of any new method of segmentation. 相似文献16.
Jaboury Ghazoul 《Biotropica》2010,42(5):578-579
I contend that our values are muddled and misplaced. As a society, Nature is grossly undervalued relative to other commodities and priorities despite its integral and central role in our psyche and culture. The increasing dissociation of humans from nature, physically, intellectually and culturally, threatens the conservation ethic and all our efforts at conserving Nature in the long term, for human benefit or for its own sake. We need to reverse the increasing human isolation from the natural environment by encouraging our children and the wider public to engage with Nature. The formative experiences thus gained might, with time, change societal priorities in favor of a renewed conservation ethic. 相似文献
17.
Thomas Mettier Roland Scholz Olaf Tietje 《The International Journal of Life Cycle Assessment》2006,11(6):394-402
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Part 1: Cognitive Limits in Panel Surveys · Part 2: The Question Format in Panel Surveys This series of two papers discusses the elicitation of weights for damage categories in LCIA with the aid of panel surveys. The papers focus especially on methodological aspects in panel surveys. Part 1 discusses potential cognitive limits of the panel members to understand the reference that is weighted. Part 2 focuses on the influence of the question format and compares results from two different weighting tasks: discrete choice (between alternatives) and score allocation.Goal, Scope and Background
The weighting of environmental impacts and damages on the safeguard subjects Human Health, Ecosystems, and Resources is a significant step of full aggregated LCIA. Panel surveys have become a common approach in LCIA research to investigate the preferences of stakeholders on environmental impacts and damages. Despite the numerous studies, the knowledge on how to elicit reliable weights is still poor and inconsistent. We present a questionnaire study with 58 environmental science students to investigate so-called framing effects in panel surveys.Main Features
The study investigates the significance of different framings, which were provided by three references. In addition, the significance of quantitative information provided in the questionnaire is tested. The references are (a1) safeguard subjects without specified additional information, (a2) damages in Europe as they are perceived by the panelist, and (a3) quantified scenarios derived from Eco-indicator99. All participants ranked and rated the importance of the safeguard subjects three times, once within each reference system. According to a test-of-scope study, quantitative information given to the panelist was varied. One level (b1) included data from the Ecoindicator99 methodology, whereas the other group (b2) received data with significantly higher Human Health damages and lower Ecosystem damages, ceteris paribus. This design allows testing the influence of quantitative data on the rating.Results
The weighting of the safeguard subjects (a1) reveals that Human Health is considered a slightly more important safeguard subject than Ecosystems. However, both are judged to be significantly more important than Resources. This picture changes for the references (a2) and (a3) where damages were weighted. For both references, the respondents rated damages to Ecosystems as most important followed by Resources and Human Health, showing by far the lowest weights. Therefore, the framing of the reference that was weighted played a significant role. The ratings of the subgroups (b1) and (b2) did not differ with respect to the importance of damages, though substantially different quantitative information was given.Conclusion and Outlook
The participants of the study were obviously insensitive with respect to quantitative information provided. This raises three questions, which are discussed. What is the mental model upon which respondents base their beliefs and values? Can we expect that 'more sophisticated' subjects would respond differently? Which prerequisites should an empirical weighting procedure fulfill in order to incorporate numerical data? We propose different approaches for future procedures in order to accurately analyze these questions. 相似文献18.
Bengt Steen 《The International Journal of Life Cycle Assessment》2006,11(4):277-283
Intention, Goal, Scope, Background It has gained growing acceptance in recent years that there are values in LCA, and several authors have discussed how value
orientations can influence LCA models and results. The aim of this article is to continue this discussion and to focus on
value choices in LCA.
Objectives To find a way of describing value orientations in relation to choices in LCA.
Methods This objective has been pursued in this paper by investigating the relationship between values and traditional science, exploring
the concept of values, investigating the relationship between values and choice, and suggesting a way to describe the value
base for specific choices in LCA.
Results and Discussion Research on how to improve the environmental performance of products resembles peace research in that it aims to achieve
a certain value-laden situation in society. The epistemological basis for peace research also seems to apply to LCA research.
The term value has many meanings. There are several classification methods for values and I claim that one is more suitable
for choices in LCA than the others. The correlation between values and choice is not straightforward, and values can only
partially explain choices.
Conclusions Describing the value base for choices in LCA increases the consistency and transparency of the value choices and offers a
means of justifying them.
Recommendations and Outlook It is recommended that the value base is described in terms of 1) what is included in the concern for the environment 2)
how tradeoffs are made and 3) how uncertainty is handled. 相似文献
19.
Valuing mangrove ecosystem services: linking nutrient retention function of mangrove forests to enhanced agroecosystem production 总被引:1,自引:0,他引:1
Mangroves are highly productive wetland ecosystems strategically located at the interface between land and sea. They play
an important role in the biogeochemical cycles of the coastal environment, acting as sources of nutrients to adjacent marine
and terrestrial ecosystems through active and passive transport. We examined the nutrient contents in mangrove and nonmangrove
soils in and around the Bhitarkanika National Park, India and assessed whether the local agricultural producers were aware
of and placed a value on this contribution of mangrove forests in enhancing agroecosystem productivity. Soil samples from
both mangrove and nonmangrove areas were analysed and quantity of organic carbon, total nitrogen, available phosphorus and
potassium were derived. The replacement cost method was used to derive the value of nutrients in mangrove soils. We estimated
that each hectare of mangrove contains additional nutrients worth US$232.49 in comparison to nonmangrove areas. The difference
in nutrient content in mangrove versus nonmangrove areas gave the value of US$3.37 million for the nutrients in 145 km2 of mangrove forests. The agricultural producers were aware that mangrove forests act as a source of nutrients and were willing
to pay a higher price for the land adjoining mangrove forests. Around 92% of the producers ranked nutrient retention as a
secondary function of mangrove forests. Despite crop depredation from wild ungulates and conflict with salt water crocodiles
the agriculturist finds the benefit to cost ratio of mangrove forests high and more than 76% were in favour of mangrove restoration.
This study provides an opportunity to highlight the importance of mangrove ecosystems to the livelihoods of the local people
and the urgent need to sustain these through proper policy and market interventions. 相似文献
20.
生物多样性价值的经济学处理:一些理论障碍及其克服 总被引:17,自引:0,他引:17
本文首先对国际生态经济学界围绕“世界生态系统功能价值计量”的方法学论争进行短简的评价,接着阐述了生物多样性价值的新的概念框架,并据此就生物多样性价值计量中尚未得到关注的问题(生物多样性价值的可计算性,价值计量方法的恰当性,价值分量的可加性和可解析性,价值误差测算)提出解决思路,本文最后讨论了两个保护经济学问题方法学构架,其一是生物多样性破坏的经济损失计算,其二是生物多样性保护工程的成本-效益体质与成本-效果分析。 相似文献