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301.
302.
This paper includes the proposals made in the report “Basis for a National Strategy for Coastal Zone Management” prepared for the Portuguese Ministry of Environment, Territorial Planning and Regional Development. The final version of that report was presented in June 2006. This paper describes a theme framework followed by a discussion of concepts. Nine Primary Principles, eight Principal Objectives, and 37 Strategic Options for an Integrated Coastal Zone Management are then presented. These Strategic Options are set hierarchically according to their sequential priority, identifying the dominant types of Associated Measures. The analysis of these arrives at a set of Structural Measures, which interlink and aggregate various actions and propose a new method of integrated management for the coastal zone, which includes the “Legal Basis of Coastal Zone”; the Organization System; the Action Plan and Monitoring.  相似文献   
303.
Environmental Fluid Mechanics - The main goal of this study is the 3D numerical simulation of river flows with submerged vegetated floodplains. Since, vegetation layers are usually dense and...  相似文献   
304.
The Leça River and two beaches close to the north and south margins of the estuary, nowadays an important seaport harbor, show signs of contamination. However, the chemical nature of that contamination is uncertain. Therefore, this study checked for the presence of 11 endocrine disrupting compounds (EDCs) of animal (17β-estradiol and estrone), pharmaceutical (17α-ethynylestradiol), and industrial (alkylphenols, alkylphenol ethoxylates, and bisphenol A) origins in water samples collected from six points at the river gradient and at two sites in the coastline (Atlantic Ocean). Along with the EDCs, evaluated by gas chromatography – mass spectroscopy (GC-MS) during spring, summer, and autumn, physico-chemical parameters were also assessed and particular attention was given to dissolved oxygen (DO) levels. Data showed the presence of high amounts of estrogens (up to 10?ng?L?1 for estrone) and industrial compounds (up to 2?µg?L?1 for the nonylphenol ethoxylates) at both river and seacoast. Along with this, clear signs of hypoxia were found in the river (DO??1 at several sampling sites). Taking into account these issues, it was concluded that there are local conditions for the occurrence of endocrine disruption in aquatic animals.  相似文献   
305.
Land use change can have a strong impact on soil carbon dynamics and carbon stocks in urban areas. Due to rapid urbanization, large areas of land have been paved, and other areas have undergone rapid land use change. Evaluation of the impact of urbanization on carbon dynamics and carbon stock (30 cm) has become an issue of urgent concern. The soil carbon dynamics, due to rapid land use change in Tianjin Binhai New Area of China, have been simulated in this paper using the RothC model. Because this area is saline, a modified version of RothC that includes a salt rate modifier provided more accurate simulations than the original model. The conversion to urban green land was not accurately simulated by either of the models because of the undefined changes in soil and plant conditions. According to the model, changes of arable to grassland resulted in a decline in soil carbon stocks, and changes of grassland to forest and grassland to arable resulted in increased soil carbon stocks in this area. Across the whole area simulated, the total carbon stocks in 2010 had decreased due to land use change by 6.5% from the 1979 value. By 2050, a further decrease of 21.9% is expected according to the 2050 plan for land use and the continuing losses from the soils due to previous land use changes.  相似文献   
306.
Given a set $X$ of $k$ points and a point $z$ in the $n$ -dimensional euclidean space, the Tukey depth of $z$ with respect to $X$ , is defined as $m/k$ , where $m$ is the minimum integer such that $z$ is not in the convex hull of some set of $k-m$ points of $X$ . If $z$ belongs to the closed region $B$ delimited by an ellipsoid, define the continuous depth of $z$ with respect to $B$ as the quotient $V(z)/\text{ Vol }(B)$ , where $V(z)$ is the minimum volume of the intersection of $B$ with the halfspaces defined by any hyperplane passing through $z$ , and $\text{ Vol }(B)$ is the volume of $B$ . We consider $z$ a random variable and prove that, if $z$ is uniformly distributed in $B$ , the continuous depth of $z$ with respect to $B$ has expected value $1/2^{n+1}$ . This result implies that if $z$ and $X$ are uniformly distributed in $B$ , the expected value of Tukey depth of $z$ with respect to $X$ converges to $1/2^{n+1}$ as the number of points $k$ goes to infinity. These findings have applications in ecology, namely within the niche theory, where it is useful to explore and characterize the distribution of points inside species niche.  相似文献   
307.
The conservation of long-distance migratory birds requires coordination between the multiple countries connected by the movements of these species. The recent expansion of tracking studies is shedding new light on these movements, but much of this information is fragmented and inaccessible to conservation practitioners and policy makers. We synthesized current knowledge on the connectivity established between countries by landbirds and raptors migrating along the African–Eurasian flyway. We reviewed tracking studies to compile migration records for 1229 individual birds, from which we derived 544 migratory links, each link corresponding to a species’ connection between a breeding country in Europe and a nonbreeding country in sub-Saharan Africa. We used these migratory links to analyze trends in knowledge over time and spatial patterns of connectivity per country (across species), per species (across countries), and at the flyway scale (across all countries and all species). The number of tracking studies available increased steadily since 2010 (particularly for landbirds), but the coverage of existing tracking data was highly incomplete. An average of 7.5% of migratory landbird species and 14.6% of raptor species were tracked per country. More data existed from central and western European countries, and it was biased toward larger bodied species. We provide species- and country-level syntheses of the migratory links we identified from the reviewed studies, involving 123 populations of 43 species, migrating between 28 European and 43 African countries. Several countries (e.g., Spain, Poland, Ethiopia, Democratic Republic of Congo) are strategic priorities for future tracking studies to complement existing data, particularly on landbirds. Despite the limitations in existing tracking data, our data and results can inform discussions under 2 key policy instruments at the flyway scale: the African–Eurasian Migratory Landbirds Action Plan and the Memorandum of Understanding on the Conservation of Migratory Birds of Prey in Africa and Eurasia.  相似文献   
308.
Production of biodiesel from waste frying oils   总被引:9,自引:0,他引:9  
Waste frying oils transesterification was studied with the purpose of achieving the best conditions for biodiesel production. Transesterification reactions were carried out for 1 h using waste frying oils (WFOs), methanol, and sodium hydroxide as catalyst. In order to determine the best conditions for biodiesel production, a series of experiments were carried out, using methanol/WFO molar ratios between 3.6 and 5.4 and catalyst/WFO weight ratios between 0.2% and 1.0%. For oils with an acid value of 0.42 mg KOH/g, results show that a methanol/WFO ratio of 4.8 and a catalyst/WFO ratio of 0.6% gives the highest yield of methyl esters. Furthermore, an increase in the amount of methanol or catalyst quantity seems to simplify the separation/purification of the methyl esters phase, as showed by a viscosity reduction and an increasing purity to values higher than 98% for methyl esters phase.  相似文献   
309.
The risk assessment of pesticides on soil fauna is an issue to protect agroecosystem sustainability. Enchytraeids are recognized as relevant soil bioindicators of chemical stress in agroecosystems. In laboratory, the reproduction test was found to be sensitive to reveal chemical impacts on enchytraeids. However, it does not allow to assess the impacts on ecological functions in which enchytraeids are involved. The objectives of this study were (i) to explore the feasibility of the bait-lamina test with enchytraeids under laboratory conditions and (ii) to compare its sensitivity with the Enchytraeid Reproduction Test. We exposed individuals of Enchytraeus albidus to two commercial formulations of fungicides widely used in Europe. The EC50 reproduction for the Swing® Gold (50 g L?1 epoxiconazole and 133 g L?1 dimoxystrobin) and the Cuprafor micro® (50% copper oxychloride) were respectively estimated at 1.66?±?0.93 times the recommended dose and >?496 mg kg?1 of copper. However, no impact was found on the feeding activity of enchytraeids. The bait-lamina test thus appeared less sensitive than the Enchytraeid Reproduction Test to the tested fungicides. Despite that, this test which is achievable under laboratory conditions and allows assessing indirect effects of pesticides is quick, cheap, and easy to perform. It would deserve to be used to explore longer-exposure effects through the repeated addition of bait-lamina sticks.  相似文献   
310.
Regional Environmental Change - Integrated farming systems (IS) are one of the main strategies of the Brazilian government to reduce or compensate for carbon emissions from agriculture with...  相似文献   
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