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91.
The EU Marine Strategy Framework Directive (MSFD) is considered to be the environmental pillar of the EU Integrated Maritime Policy, establishing a framework within which member states must take the necessary measures to achieve, or maintain, good environmental status in their marine waters. This study presents Portugal's contributions to the Directive development, describes the Portuguese institutional framework within the MSFD and, finally, highlights the opportunities and threats to the success of the MSFD implementation in Portugal. The latter entails an analysis of the Directive's long term adequacy in its link to (1) marine spatial planning, (2) climate change and (3) the economic/financial crisis. With one of Europe's largest exclusive economic zones. Portugal's interest in the MSFD is paramount. Efforts towards the approval of the final document were assured during the Portuguese presidency of the European Council of Ministers, in 2007, while chairing a thorough discussion between the Council and the European Parliament. In the Portuguese context, the Directive implementation will rely on the Water Institute as the authoritative entity, which will be responsible for coordinating all necessary efforts at the national level. The success of such process depends on a close cooperation among the institutions involved as well as on how approved measures account for long term issues. In addition, the MSFD implementation must be built on lessons learned within the Water Framework Directive, in order to be successful. Although it poses a methodological challenge to Portugal, the MSFD implementation is expected to contribute significantly to the improvement of coastal/marine conservation and management at the national level.  相似文献   
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93.
Sagebrush ecosystems of the western US provide important habitat for several ungulate and vertebrate species. As a consequence of energy development, these ecosystems in Wyoming have been subjected to a variety of anthropogenic disturbances. Land managers require methodology that will allow them to consistently catalog sagebrush ecosystems and evaluate potential impact of proposed anthropogenic activities. This study addresses the utility of remotely sensed and ancillary geospatial data to estimate sagebrush cover using ordinal logistic regression. We demonstrate statistically significant prediction of ordinal sagebrush cover categories using spectral (χ2 = 113; p < 0.0001) and transformed indices (χ2 = 117; p < 0.0001). Both Landsat spectral bands (c-value = 0.88) and transformed indices (c-value = 0.89) can distinguish sites with closed, moderate and open cover sagebrush cover categories from no cover. The techniques described in this study can be used for estimating categories of sagebrush cover in arid ecosystems.  相似文献   
94.
Rock falls represent a large percentage of landslide-related hazards reported by Canadian railways in mountainous terrain. A 54.7?km-long section of railway through the Canadian Cordillera is examined that experiences, on average, 18 rock falls each year. An approach for rock fall hazard management is developed based on quantified risk. The approach focuses on defining railway operation procedures (freight train operations and track maintenance) that comply with quantified risks. Weather-based criteria that define periods when rock falls are more likely to occur along the study area are examined. These criteria are used herein to reduce exposure to rock falls and reduce their consequences. Several freight train operation strategies are proposed that comply with a tolerable level of risk adopted in this study for illustrative purposes. The approach provides a simple, flexible and practical strategy for railway operations that can be regularly adopted by the operators, and that is based on a more comprehensive assessment of quantified risk.  相似文献   
95.
A significant fraction of the total number of particles present in the atmosphere is formed by nucleation in the gas phase. Nucleation and the subsequent growth process influence both number concentration of particles and their size distribution besides chemical and optical properties of atmospheric aerosols. Sulphate aerosol nucleation mechanisms promoted by ions have been evaluated here in a tropospheric interactive chemistry-aerosol module for mass and number concentration in a global atmospheric model. The indirect radiative forcing of sulphate particles is assessed in this model; indirect radiative forcing is different for ion-induced (IIN) and ion-mediated (IMN) mechanisms. The indirect radiative forcing in 10-year simulation runs has been calculated as ?1.42?W/m2 (IIN) and ?1.54?W/m2 (IMN). The 5% emission of primary sulphate particles in simulations changes the indirect radiative forcing from ?1.42 to ?1.44?W/m2 for IIN case, and from ?1.54 to ?1.55 W/m2 for the IMN case. More precisely, owing to greater nucleation rates, IMN mechanisms produces greater cooling than the IIN mechanisms in the backdrop that both mechanisms produce almost identical distribution of CDNC in their pre-industrial runs. The inclusion of primary particles in simulations with IIN and IMN mechanisms increases both CDNC and the indirect radiative forcing.  相似文献   
96.
The characteristics of rain and point charges based on routine measurements extending over four rainy seasons are presented. An average rain current density of (1.0±0.1)×10–10 A m–2 and charge per unit volume of rain water of (0.43±0.02)×10–4 C m–3 for the locality are obtained, which are compared with data obtained elsewhere by other workers. The point-discharge current measurements lead to a revised estimate of (0.86±0.08)×10–9 A m–2 for the average point discharge current below storm clouds.  相似文献   
97.
In this paper we present the results of the past two years observations on the galactic microquasar LS I +61 303 with the Whipple 10 m gamma-ray telescope. The recent MAGIC detection of the source between 200 GeV and 4 TeV suggests that the source is periodic with very high energy (VHE) gamma-ray emission linked to its orbital cycle. The entire 50-hour data set obtained with Whipple from 2004 to 2006 was analyzed with no reliable detection resulting. The upper limits obtained in the 2005–2006 season covered several of the same epochs as the MAGIC Telescope detections, albeit with lower sensitivity. Upper limits are placed on emission during the orbital phases of 0→0.1 and 0.8→1, phases which are not included in the MAGIC data set.   相似文献   
98.
Picoplankton abundance and distribution in the Mississippi River plume and its adjacent waters were studied during two cruises in April (high discharge) and October (low discharge) 2000 using flow cytometry. Concentrations of photosynthetic picoplankton,Synechococcus and picoeukaryotes were low in the turbid plume water but high in the coastal waters—i.e., the green waters resulting from mixing of river and oceanic waters. In this region, three types ofSynechococcus, characterized by their phycoerythrin chromophore composition, were found:Synechococcus cells with a low phycourobilin to phycoerythrobilin ratio (PUB:PEB) occurred throughout the region and dominated the totalSymechococcus abundance during both seasons; high PUB:PEB cells, which are the dominant strains in the open or blue ocean, occurred only at the outer shelf stations; and PEB-onlySynechococcus were abundant in most of the surveyed area during april, but were not observed during October.Prochlorococcus cyanobacteria only occurred at the oceanic stations, but extended farther inshore in October compared to April. This was a consequence of the reduced discharge and plume size during October. Picophytoplankton were a less important component of total phytoplankton biomass in the turbid river water and more important in the oligotrophic Gulf water. Seasonally, the contribution of picophytoplankton to total phytoplankton biomass in the surveyed area was higher during low discharge in October than during high discharge in April, even though the spring 2000 river discharge was unusually low and might not present a typical high discharge scenario. The abundance of heterotrophic bacteria was weakly correlated to chlorophylla (chla) concentration, but better correlated to picophytoplankton biomass. A higher proportion of High DNA bacteria occurred in the river-impacted regions during both seasons, with the ratio of High DNA bacteria to Low DNA bacteria significantly higher in April.  相似文献   
99.
Several measurements have been performed to find antiprotons in the primary cosmic radiation. Because it is difficult to get completely separated secondary produced antiprotons primary ones, calculations based on accelerator results have been performed for the flux of secondary produced antideuterons and antihelium.  相似文献   
100.
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