790 resultados para Trends and Challenges


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A new tropopause definition involving a flow-dependent blending of the traditional thermal tropopause with one based on potential vorticity has been developed and applied to the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalyses (ERA), ERA-40 and ERA-Interim. Global and regional trends in tropopause characteristics for annual and solsticial seasonal means are presented here, with emphasis on significant results for the newer ERA-Interim data for 1989-2007. The global-mean tropopause is rising at a rate of 47 m decade−1 , with pressure falling at 1.0 hPa decade−1 , and temperature falling at 0.18 K decade−1 . The Antarctic tropopause shows decreasing heights,warming,and increasing westerly winds. The Arctic tropopause also shows a warming, but with decreasing westerly winds. In the tropics the trends are small, but at the latitudes of the sub-tropical jets they are almost double the global values. It is found that these changes are mainly concentrated in the eastern hemisphere. Previous and new metrics for the rate of broadening of the tropics, based on both height and wind, give trends in the range 0.9◦ decade−1 to 2.2◦ decade−1 . For ERA-40 the global height and pressure trends for the period 1979-2001 are similar: 39 m decade−1 and -0.8 hPa decade−1. These values are smaller than those found from the thermal tropopause definition with this data set, as was used in most previous studies.

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Elephant poaching and the ivory trade remain high on the agenda at meetings of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Well-informed debates require robust estimates of trends, the spatial distribution of poaching, and drivers of poaching. We present an analysis of trends and drivers of an indicator of elephant poaching of all elephant species. The site-based monitoring system known as Monitoring the Illegal Killing of Elephants (MIKE), set up by the 10th Conference of the Parties of CITES in 1997, produces carcass encounter data reported mainly by anti-poaching patrols. Data analyzed were site by year totals of 6,337 carcasses from 66 sites in Africa and Asia from 2002–2009. Analysis of these observational data is a serious challenge to traditional statistical methods because of the opportunistic and non-random nature of patrols, and the heterogeneity across sites. Adopting a Bayesian hierarchical modeling approach, we used the proportion of carcasses that were illegally killed (PIKE) as a poaching index, to estimate the trend and the effects of site- and country-level factors associated with poaching. Important drivers of illegal killing that emerged at country level were poor governance and low levels of human development, and at site level, forest cover and area of the site in regions where human population density is low. After a drop from 2002, PIKE remained fairly constant from 2003 until 2006, after which it increased until 2008. The results for 2009 indicate a decline. Sites with PIKE ranging from the lowest to the highest were identified. The results of the analysis provide a sound information base for scientific evidence-based decision making in the CITES process.

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Integrated simulation models can be useful tools in farming system research. This chapter reviews three commonly used approaches, i.e. linear programming, system dynamics and agent-based models. Applications of each approach are presented and strengths and drawbacks discussed. We argue that, despite some challenges, mainly related to the integration of different approaches, model validation and the representation of human agents, integrated simulation models contribute important insights to the analysis of farming systems. They help unravelling the complex and dynamic interactions and feedbacks among bio-physical, socio-economic, and institutional components across scales and levels in farming systems. In addition, they can provide a platform for integrative research, and can support transdisciplinary research by functioning as learning platforms in participatory processes.

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Reliable techniques for screening large numbers of plants for root traits are still being developed, but include aeroponic, hydroponic and agar plate systems. Coupled with digital cameras and image analysis software, these systems permit the rapid measurement of root numbers, length and diameter in moderate ( typically <1000) numbers of plants. Usually such systems are employed with relatively small seedlings, and information is recorded in 2D. Recent developments in X-ray microtomography have facilitated 3D non-invasive measurement of small root systems grown in solid media, allowing angular distributions to be obtained in addition to numbers and length. However, because of the time taken to scan samples, only a small number can be screened (typically<10 per day, not including analysis time of the large spatial datasets generated) and, depending on sample size, limited resolution may mean that fine roots remain unresolved. Although agar plates allow differences between lines and genotypes to be discerned in young seedlings, the rank order may not be the same when the same materials are grown in solid media. For example, root length of dwarfing wheat ( Triticum aestivum L.) lines grown on agar plates was increased by similar to 40% relative to wild-type and semi-dwarfing lines, but in a sandy loam soil under well watered conditions it was decreased by 24-33%. Such differences in ranking suggest that significant soil environment-genotype interactions are occurring. Developments in instruments and software mean that a combination of high-throughput simple screens and more in-depth examination of root-soil interactions is becoming viable.

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The first part of this review examines what is meant by ‘urban land and property’ (ULP) and looks at the background of ULP in the light of trends in UK urban areas over the past 50 years. Key conceptual approaches to the ULP ‘ownership issue’ are identified, together with the constraints to empirical analysis, which include a lack of data and patchy and inconsistent datasets. Three main components of ULP ownership in the UK are then examined using published data on commercial property, residential property and urban land, including ‘previously developed land’ (PDL) and ‘development land, covering both the private and public sectors. The review examines past trends in ULP ownership patterns in these sectors within the UK, and the key drivers which have created the present day patterns of ULP ownership. It concludes by identifying possible future trends in ULP ownership over the next 50 years to 2060 in the three main ULP sectors.

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Over the last decade the important role that local authorities can play in catalyzing communityaction on climate change has been repeatedly emphasised by the UK Government. The paper examines this policy context and explores the options available to local authorities in terms of reaching and engaging their communities. The type of progressive response shown by some UKlocal authorities is illustrated with empirical evidence gathered through a study conducted in the London Borough of Islington focusing on their recently established ‘Green Living Centre’. The results confirm interest in this major council-led community initiative, with positive attitudes expressed by the majority of those questioned in terms of the advice and information available. However, it is also clear that many participants had preexisting pro-environmental attitudes and behavioural routines. Results from a broader sample of Islington residents indicate a substantial challenge in reaching the wider community, where enthusiasm for sustainability change and interest in this type of scheme were more mixed. The prospect for local government in addressing this challenge – and their ability to trigger and capitalize upon concepts of social change at the community level towardsalowercarbon future – is discussed in the final part of the paper.

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Temperature and precipitation are major forcing factors influencing grapevine phenology and yield, as well as wine quality. Bioclimatic indices describing the suitability of a particular region for wine production are a commonly used tool for viticultural zoning. For this research these indices were computed for Europe by using the E-OBS gridded daily temperature and precipitation data set for the period from 1950 to 2009. Results showed strong regional contrasts based on the different index patterns and reproduced the wide diversity of local conditions that largely explain the quality and diversity of grapevines being grown across Europe. Owing to the strong inter-annual variability in the indices, a trend analysis and a principal component analysis were applied together with an assessment of their mean patterns. Significant trends were identified in the Winkler and Huglin indices, particularly for southwestern Europe. Four statistically significant orthogonal modes of variability were isolated for the Huglin index (HI), jointly representing 82% of the total variance in Europe. The leading mode was largely dominant (48% of variance) and mainly reflected the observed historical long-term changes. The other 3 modes corresponded to regional dipoles within Europe. Despite the relevance of local and regional climatic characteristics to grapevines, it was demonstrated via canonical correlation analysis that the observed inter-annual variability of the HI was strongly controlled by the large-scale atmospheric circulation during the growing season (April to September).

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A climatology of cyclones with a focus on their relation to wind storm tracks in the Mediterranean region (MR) is presented. Trends in the frequency of cyclones and wind storms, as well as variations associated with the North Atlantic Oscillation (NAO), the East Atlantic/West Russian (EAWR) and the Scandinavian variability pattern (SCAND) are discussed. The study is based on the ERA40 reanalysis dataset. Wind storm tracks are identified by tracking clusters of adjacent grid boxes characterised by extremely high local wind speeds. The wind track is assigned to a cyclone track independently identified with an objective scheme. Areas with high wind activity – quantified by extreme wind tracks – are typically located south of the Golf of Genoa, south of Cyprus, southeast of Sicily and west of the Iberian Peninsula. About 69% of the wind storms are caused by cyclones located in the Mediterranean region, while the remaining 31% can be attributed to North Atlantic or Northern European cyclones. The North Atlantic Oscillation, the East Atlantic/West Russian pattern and the Scandinavian pattern all influence the amount and spatial distribution of wind inducing cyclones and wind events in the MR. The strongest signals exist for the NAO and the EAWR pattern, which are both associated with an increase in the number of organised strong wind events in the eastern MR during their positive phase. On the other hand, the storm numbers decrease over the western MR for the positive phase of the NAO and over the central MR during the positive phase of the EAWR pattern. The positive phase of the Scandinavian pattern is associated with a decrease in the number of winter wind storms over most of the MR. A third of the trends in the number of wind storms and wind producing cyclones during the winter season of the ERA40 period may be attributed to the variability of the North Atlantic Oscillation.

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The construction industry is widely being criticised as a fragmented industry. There are mounting calls for the industry to change. The espoused change calls for collaboration as well as embracing innovation in the process of design, construction and across the supply chain. Innovation and the application of emerging technologies are seen as enablers for integrating the processes ‘integrating the team’ such as building information modelling (BIM). A questionnaire survey was conducted to ascertain change in construction with regard to design management, innovation and the application of BIM as cutting edge pathways for collaboration. The respondents to the survey were from an array of designations across the construction industry such as construction managers, designers, engineers, design coordinators, design managers, architects, architectural technologists and surveyors. There was a general agreement by most respondents that the design team was responsible for design management in their organisation. There is a perception that the design manager and the client are the catalyst for advancing innovation. The current state of industry in terms of incorporating BIM technologies is posing a challenge as well as providing an opportunity for accomplishment. BIM technologies provide a new paradigm shift in the way buildings are designed, constructed and maintained. This paradigm shift calls for rethinking the curriculum for educating building professionals, collectively.

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In this study, change in rainfall, temperature and river discharge are analysed over the last three decades in Central Vietnam. Trends and rainfall indices are evaluated using non-parametric tests at different temporal levels. To overcome the sparse locally available network, the high resolution APHRODITE gridded dataset is used in addition to the existing rain gauges. Finally, existing linkages between discharge changes and trends in rainfall and temperature are explored. Results are indicative of an intensification of rainfall (+15%/decade), with more extreme and longer events. A significant increase in winter rainfall and a decrease in consecutive dry days provides strong evidence for a lengthening wet season in Central Vietnam. In addition, trends based on APHRODITE suggest a strong orographic signal in winter and annual trends. These results underline the local variability in the impacts of climatic change at the global scale. Consequently, it is important that change detection investigations are conducted at the local scale. A very weak signal is detected in the trend of minimum temperature (+0.2°C/decade). River discharge trends show an increase in mean discharge (31 to 35%/decade) over the last decades. Between 54 and 74% of this increase is explained by the increase in precipitation. The maximum discharge also responds significantly to precipitation changes leading to a lengthened wet season and an increase in extreme rainfall events. Such trends can be linked with a likely increase in floods in Central Vietnam, which is important for future adaptation planning and management and flood preparedness in the region. Copyright © 2012 John Wiley & Sons, Ltd.

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Despite the ongoing dialogue on facilitating mobility between the European Union and the Eastern Partnership (EaP) countries, very little is known about the magnitude and characteristics of migration from these countries. We find that EaP migrants experience worse labor market outcomes than other migrant groups, but current and potential migrants hold qualifications in those areas were skill shortages are expected. Therefore, the monitoring and supervision of EaP integration will be consequential in order to understand how much of the current brain waste is driven by poor assessment of foreign qualifications, and to unleash the potential of migration for the German economy.

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Mulsemedia—multiple sensorial media—captures a wide variety of research efforts and applications. This article presents a historic perspective on mulsemedia work and reviews current developments in the area. These take place across the traditional multimedia spectrum—from virtual reality applications to computer games—as well as efforts in the arts, gastronomy, and therapy, to mention a few. We also describe standardization efforts, via the MPEG-V standard, and identify future developments and exciting challenges the community needs to overcome.

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This chapter explores the spatialities of children's rights through a focus on how children's paid and unpaid work in Sub-Saharan Africa intersects with wider debates about child labor, child domestic work and young caregiving. Several tensions surround the universalist and individualistic nature of the rights discourse in the context of Sub-Saharan Africa and policymakers, practitioners, children and community members have emphasized children's responsibilities to their families and communities, as well as their rights. The limitations of ILO definitions of child labor and child domestic work and UNCRC concerns about 'hazardous' and 'harmful' work are highlighted through examining the situation of children providing unpaid domestic and care support to family members in the private space of their own or a relative's home. Differing perspectives towards young caregiving have been adopted to date by policymakers and practitioners in East Africa, ranging from a child labor/ child protection/ abolitionist approach, to a 'young carers'/ child-centered rights perspective. These differing perspectives influence the level and nature of support and resources that children involved in care work may be able to access. A contextual, multi-sectorial approach to young caregiving is needed that seeks to understand children's, family members' and community members' perceptions of what constitutes inappropriate caring responsibilities within particular cultural contexts and how these should best be alleviated.