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131.
Martin Moravčík Zuzana Sarvašová Ján Merganič Matej Schwarz 《Environmental management》2010,46(6):908-919
The article analyses the possibilities of developing an integrated indicator and a model of the assessment of forests naturalness
using the data from the database of mountainous spruce forests situated in the Western Carpathians of Slovakia. The article
presents two variants of such a model, one based on discriminant analysis, while the second one using an additive approach.
The analysis of the data from mountainous spruce forests revealed significant indicators of forest naturalness degree: the
arithmetic mean of the ratio between crown length and tree height, the deadwood volume, the coverage of grasses, the coverage
of mosses and lichens, and the aggregation index. In addition, the coefficient of variation of tree diameters was included
in the final model, since its presence in the model had a positive influence on the correctness of the classification of the
forest naturalness degree. The correctness of the classification of the proposed discriminant model was 74.5%. For the additive
model, the ranges of the values of the integrated indicator were defined for every degree of forest naturalness by taking
into account the error ranges of the arithmetic mean values and the percentiles of the values in individual degrees of forest
naturalness. The overall correctness of the classification with the additive model was 63.4%. In the second step, the scheme
how to apply the classification model of the forest naturalness degree in the decision-making process of designating as a
forest protected areas was proposed. In this scheme, the degree of forest naturalness is considered as a basic criterion for
the determination of nature-conservation value of forest ecosystems. As further decision-making criteria we identified the
possibility to restore, or the possibility to improve the naturalness of less natural forest ecosystems, which are designated
as protected; the occurrence of the endangered species; and the occurrence of other natural values. 相似文献
132.
The fluorinated compounds sulphur hexafluoride (SF6), perfluorocarbons (CF4, C2F6) and hydrofluorocarbons (HFCs) are atmospheric trace gases with extremely high global warming potentials (GWP). The study examines the real emissions of these compounds in Germany between 1990 and 1995, and develops projections for the years up to 2020. These projections indicate that annual perfluorocarbon releases will drop between the years 1990 and 2000 from 335 t/34 t to 100 t/10 t due to automation measures at the main source (aluminium smelting). Sulphur hexafluoride emissions, however, will remain in the range between 200 and 300 t per annum until the year 2020. By far the largest emitters are car tyres and sound-insulation glazing, non-electrical swithgear, the latter being relatively well sealed and linked to management and reprocessing concepts for used gas. As concerns hydrofluorocarbons which have only been used since 1990 with the specific intention of substituting chlorofluorocarbons (CFCs), an increasing degree of CFC substitution in stationary and mobile refrigeration technology, in canned PUR foams and in asthma sprays must be expected to lead to steeply rising emissions to levels exceeding 9,700 t/a from the year 2007 onwards, if halogen-free alternatives are not used more strongly. Assuming these trends, the cumulative emissions of the stated fluorinated compounds will correspond to a global warming impact of 25 million t CO2 (GWP time horizon: 100 years) by the year 2020. 相似文献
133.
134.
In situ measurements of seagrass photosynthesis in relation to inorganic carbon (Ci) availability, increased pH and an inhibitor
of extracellular carbonic anhydrase were made using an underwater pulse amplitude modulated (PAM) fluorometer. By combining
the instrument with a specially designed Perspex chamber, we were able to alter the water surrounding a leaf without removing
it from the growing plant. Responses to Ci within the chamber showed that subtidal plants of the seagrasses Cymodocea serrulata and Halophila ovalis had photosynthetic rates that were limited by the ambient Ci concentration depending on the irradiance that was available
during short-term photosynthesis–irradiance trials. Relative electron transport rates (RETRs) at light saturation (up to 500 μ
mol photons m−2 s−1) increased by 66–100% when the Ci concentration was increased from ca. 2.2 to 6.2 mM. On the other hand, intertidal plants
of the same species exhibited a much lesser limitation of photosynthesis by Ci at any irradiance (up to 1500 μ mol photons
m−2 s−1). Both species were able to use HCO−
3 efficiently, and there was stronger evidence for direct uptake of HCO−
3 rather than extracellular dehydration of HCO−
3 to CO2 prior to Ci uptake. Subtidally, H. ovalis and C. serrulata grew to 10 and 12 m, respectively, where ambient irradiances were approximately 16 and 11% of those at the surface. Maximum
RETRs (at light saturation) were lower for these deep-growing plants than for the intertidally growing ones. For both species,
the onset of light saturation of photosynthesis (E
k) occurred at approximately 100 μ mol photons m−2 s−1 for the deep water populations, which was four and two times lower than for the shallow populations of C. serrulata and H. ovalis, respectively. This, and the differences in maximal photosynthetic rates (RETR
max), reflects an acclimation of the deep-growing populations to the lower light environment. The results presented here show
that photosynthesis, as measured in situ, was limited by the availability of Ci for the deeper growing plants in Zanzibar,
while the intertidally growing plants photosynthesised at close to Ci saturation. The latter result is contrary to previous
conclusions regarding Ci limitations for these intertidal plants, and, in general, our findings highlight the need for performing
similar experiments in situ rather than under laboratory conditions.
Received: 4 April 2000 / Accepted: 31 August 2000 相似文献
135.
Adaptation to Climate Change in Developing Countries 总被引:2,自引:0,他引:2
Ole Mertz Kirsten Halsnæs Jørgen E. Olesen Kjeld Rasmussen 《Environmental management》2009,43(5):743-752
Adaptation to climate change is given increasing international attention as the confidence in climate change projections is
getting higher. Developing countries have specific needs for adaptation due to high vulnerabilities, and they will in this
way carry a great part of the global costs of climate change although the rising atmospheric greenhouse gas concentrations
are mainly the responsibility of industrialized countries. This article provides a status of climate change adaptation in
developing countries. An overview of observed and projected climate change is given, and recent literature on impacts, vulnerability,
and adaptation are reviewed, including the emerging focus on mainstreaming of climate change and adaptation in development
plans and programs. The article also serves as an introduction to the seven research articles of this special issue on climate
change adaptation in developing countries. It is concluded that although many useful steps have been taken in the direction
of ensuring adequate adaptation in developing countries, much work still remains to fully understand the drivers of past adaptation
efforts, the need for future adaptation, and how to mainstream climate into general development policies. 相似文献
136.
Development and Climate Change: A Mainstreaming Approach for Assessing Economic,Social, and Environmental Impacts of Adaptation Measures 总被引:2,自引:1,他引:1
The paper introduces the so-called climate change mainstreaming approach, where vulnerability and adaptation measures are
assessed in the context of general development policy objectives. The approach is based on the application of a limited set
of indicators. These indicators are selected as representatives of focal development policy objectives, and a stepwise approach
for addressing climate change impacts, development linkages, and the economic, social and environmental dimensions related
to vulnerability and adaptation are introduced. Within this context it is illustrated using three case studies how development
policy indicators in practice can be used to assess climate change impacts and adaptation measures based on three case studies,
namely a road project in flood prone areas of Mozambique, rainwater harvesting in the agricultural sector in Tanzania and
malaria protection in Tanzania. The conclusions of the paper confirm that climate risks can be reduced at relatively low costs,
but the uncertainty is still remaining about some of the wider development impacts of implementing climate change adaptation
measures. 相似文献
137.
Sebastiaan J.H. Rietjens Kirsten Verlaan Thijs W. Brocades Zaalberg Sirp J. De Boer 《Disasters》2009,33(3):412-435
This paper seeks to contribute to an improved information management and exchange between humanitarian organisations and military agents in complex emergencies. To do so, a theoretical information management process model was developed and applied to the case of information management between International Security Assistance Force troops and humanitarian organisations such as Cordaid, DACAAR and the International Office for Migration in Kabul, Afghanistan. Based on this analysis the main shortcomings and problems in each stage of the information management process were identified. These include a lack of structured information databases, the absence of identification of information needs, and an over‐classification of documents by the military. Using a logical framework analysis, six major improvement tactics were developed, including the creation of more overlap in rotations of personnel, the specification of aims and tasks regarding information management, the improvement of skills and competences of personnel involved, and the introduction of regular joint civil–military evaluations. 相似文献
138.
The North Water is a recurrent polynya in the High Arctic situated between Northwest Greenland and Ellesmere Island of Canada. The North Water makes a dynamic space, where various processes may enhance or obstruct each other, accelerating or halting particular modes of human–animal relations in the region, where life itself depends on the North Water. This will be discussed in four steps. The first step posits the North Water as a perceived oasis for explorers and whalers hailing from Europe or America in the nineteenth century. The second step concentrates on the diverse rhythms inherent in the ice conditions, as affected by trends that are set in motion elsewhere. The third step highlights the implications of the dynamics of the ice and sea currents for animal life in the region. The fourth step gives an overview of human settlement patterns around the North Water across the ages. The article shows how natural and social features are deeply implicated in each other, even if they are not directly co-variant. 相似文献
139.
Chris Schwarz John Gaspar Thomas Miller Reza Yousefian 《Traffic injury prevention》2019,20(4):S157-S161
AbstractObjective: Drowsiness is a major cause of driver impairment leading to crashes and fatalities. Research has established the ability to detect drowsiness with various kinds of sensors. We studied drowsy driving in a high-fidelity driving simulator and evaluated the ability of an automotive production-ready driver monitoring system (DMS) to detect drowsy driving. Additionally, this feature was compared to and combined with signals from vehicle-based sensors.Methods: The National Advanced Driving Simulator was used to expose drivers to long, monotonous drives. Twenty participants drove for about 4?h in the simulator between 10 p.m. and 2 a.m. They were allowed to use cruise control and traffic was sparse and semirandom, with both slower- and faster-moving vehicles. Observational ratings of drowsiness (ORDs) were used as the ground truth for drowsiness, and several dependent measures were calculated from vehicle and DMS signals. Drowsiness classification models were created that used only vehicle signals, only driver monitoring signals, and a combination of the 2 sources.Results: The model that used DMS signals performed better than the one that used only vehicle signals; however, the combination of the two performed the best. The models were effective at discriminating low levels of drowsiness from moderate to severe drowsiness; however, they were not effective at telling the difference between moderate and severe levels. A binary model that lumped drowsiness into 2 classes had an area under the receiver operating characteristic (ROC) curve of 0.897.Conclusions: Blinks and saccades have been shown to be predictive of microsleeps; however, it may be that detection of microsleeps and lane departures occurs too late. Therefore, it is encouraging that the model was able to distinguish mild from moderate drowsy driving. The use of automation may make vehicle-based signals useless for characterizing driver states, providing further motivation for a DMS. Future improvements in impairment detection systems may be expected through a combination of improved hardware, physiological measures from unobtrusive sensors and wearables, and the intelligent integration of environmental variables like time of day and time on task. 相似文献
140.
Kylie Soanes Michael Sievers Yung En Chee Nicholas S. G. Williams Manisha Bhardwaj Adrian J. Marshall Kirsten M. Parris 《Conservation biology》2019,33(2):300-306
Despite repeated calls to action, proposals for urban conservation are often met with surprise or scepticism. There remains a pervasive narrative in policy, practice, and the public psyche that urban environments, although useful for engaging people with nature or providing ecosystem services, are of little conservation value. We argue that the tendency to overlook the conservation value of urban environments stems from misconceptions about the ability of native species to persist within cities and towns and that this, in turn, hinders effective conservation action. However, recent scientific evidence shows that these assumptions do not always hold. Although it is generally true that increasing the size, quality, and connectivity of habitat patches will improve the probability that a species can persist, the inverse is not that small, degraded, or fragmented habitats found in urban environments are worthless. In light of these findings we propose updated messages that guide and inspire researchers, practitioners, and decision makers to undertake conservation action in urban environments: consider small spaces, recognize unconventional habitats, test creative solutions, and use science to minimize the impacts of future urban development. 相似文献