624 research outputs found
Impacts of climate change in coastal systems in Europe. PESETA-Coastal Systems study
Results of the physical impacts and adaptation cost assessment of sea-level rise for the European Union are presented for the A2 and B2 SRES socio-economic storylines and for a range of plausible sea-level rise scenarios, using data from the ECHAM4 and HADCM3 Global Climate Models (GCMs) models. In addition, to better understand the sensitivity of the results to the magnitude of sea-level rise, the full IPCC (2001) range of sea level rise predictions and scenarios of no climate change have also been modelled. These results are all derived using the global Dynamic Interactive Vulnerability Assessment (DIVA) tool for assessing regional to global coastal impacts and adaptation.
Both the physical and economic impacts of sea-level rise increase with time for both the A2 and B2 storylines, especially under scenarios of high sea-level rise. Without adaptation, significant impacts and therefore damages are apparent. Significant populations are threatened with displacement by flooding and coastal erosion. An exploratory adaptation analysis using standard protection measures of dike construction and beach nourishment, where benefit-cost analysis suggests this is the optimum response, reduces these impacts significantly. While adaptation in Europe is likely to be much more diverse than these two smple options, these results demonstrate the significant benefits of protection, and more generally suggest that widespread adaptation to sustain human coastal activities would be prudent. Moreover, under these protection assumptions, coastal ecosystems are significantly reduced in area, especially under the high sea-level rise scenario and climate change raises significant challenges for wider coastal management in Europe, even if human uses in the coastal zone are protected.JRC.DG.J.2-The economics of climate change, energy and transpor
Study of mechanical aspects of leak tightness in a pressure relief valve using advanced FE-analysis
This paper presents a numerical study involving the deformation of contact faces in the metal-to-metal seal in a typical pressure relief valve. The valve geometry is simplified to an axisymmetric problem, which comprises a simple geometry consisting of only 3 components. A cylindrical nozzle, which has a valve seat on top, contacts with a disk, which is preloaded by a compressed linear spring. All the components are made of AISI type 316N(L) steel defined using the multilinear kinematic hardening model based on monotonic and cyclic tests at 20°C. In-service observations show that there is a limited fluid leakage through the valve seat at operational pressures about 90% of the set pressure, which is caused by the fluid penetrating into surface asperities at the microscale. Nonlinear FEA in ANSYS using the fluid pressure penetration (FPP) technique revealed that there is a limited amount of fluid penetrating into gap, which is caused by the plastic deformation of the valve seat at the macroscale. Prediction of the fluid pressure distribution over the valve seat just before the valve lift is addressed in this study considering the FPP interaction on multiscale. This is the principal scope, since it allows adjustment of the valve spring force in order to improve the leak tightness
Population dynamics, delta vulnerability and environmental change: comparison of the Mekong, Ganges–Brahmaputra and Amazon delta regions
Tropical delta regions are at risk of multiple threats including relative sea level rise and human alterations, making them more and more vulnerable to extreme floods, storms, surges, salinity intrusion, and other hazards which could also increase in magnitude and frequency with a changing climate. Given the environmental vulnerability of tropical deltas, understanding the interlinkages between population dynamics and environmental change in these regions is crucial for ensuring efficient policy planning and progress toward social and ecological sustainability. Here, we provide an overview of population trends and dynamics in the Ganges–Brahmaputra, Mekong and Amazon deltas. Using multiple data sources, including census data and Demographic and Health Surveys, a discussion regarding the components of population change is undertaken in the context of environmental factors affecting the demographic landscape of the three delta regions. We find that the demographic trends in all cases are broadly reflective of national trends, although important differences exist within and across the study areas. Moreover, all three delta regions have been experiencing shifts in population structures resulting in aging populations, the latter being most rapid in the Mekong delta. The environmental impacts on the different components of population change are important, and more extensive research is required to effectively quantify the underlying relationships. The paper concludes by discussing selected policy implications in the context of sustainable development of delta regions and beyond
Developmental Regulation of an Adhesin Gene during Cellular Morphogenesis in the Fungal Pathogen Candida albicans
Peer reviewedPublisher PD
Updated restraint dictionaries for carbohydrates in the pyranose form
Restraint dictionaries are used during macromolecular structure refinement to encapsulate intramolecular connectivity and geometric information. These dictionaries allow previously determined 'ideal' values of features such as bond lengths, angles and torsions to be used as restraint targets. During refinement, restraints influence the model to adopt a conformation that agrees with prior observation. This is especially important when refining crystal structures of glycosylated proteins, as their resolutions tend to be worse than those of nonglycosylated proteins. Pyranosides, the overwhelming majority component in all forms of protein glycosylation, often display conformational errors in crystal structures. Whilst many of these flaws usually relate to model building, refinement issues may also have their root in suboptimal restraint dictionaries. In order to avoid subsequent misinterpretation and to improve the quality of all pyranose monosaccharide entries in the CCP4 Monomer Library, new dictionaries with improved ring torsion restraints, coordinates reflecting the lowest-energy ring pucker and updated geometry have been produced and evaluated. These new dictionaries are now part of the CCP4 Monomer Library and will be released with CCP4 version 8.0
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The global and regional impacts of climate change under Representative Concentration Pathway forcings and Shared Socioeconomic Pathway socioeconomic scenarios
This paper presents an evaluation of the global and regional consequences of climate change for heat extremes, water resources, river and coastal flooding, droughts, agriculture and energy use. It presents change in hazard and resource base under different rates of climate change (Representative Concentration Pathways: RCP), and socio-economic impacts are estimated for each combination of RCP and Shared Socioeconomic Pathway. Uncertainty in the regional pattern of climate change is characterised by CMIP5 climate model projections. The analysis adopts a novel approach using relationships between level of warming and impact to rapidly estimate impacts under any climate forcing. The projections provided here can be used to inform assessments of the implications of climate change. At the global scale all the consequences of climate change considered here are adverse, with large increases under the highest rates of warming. Under the highest forcing the global average annual chance of a major heatwave increases from 5% now to 97% in 2100, the average proportion of time in drought increases from 7% to 27%, and the average chance of the current 50-year flood increases from 2% to 7%. The socio-economic impacts of these climate changes are determined by socio-economic scenario. There is variability in impact across regions, reflecting variability in projected changes in precipitation and temperature. The range in the estimated impacts can be large, due to uncertainty in future emissions and future socio-economic conditions and scientific uncertainty in how climate changes in response to future emissions. For the temperature-based indicators, the largest source of scientific uncertainty is in the estimated magnitude of equilibrium climate sensitivity, but for the indicators determined by precipitation the largest source is in the estimated spatial and seasonal pattern of changes in precipitation. By 2100 the range across socio-economic scenario is often greater than the range across the forcing levels
Faint Infrared Flares from the Microquasar GRS 1915+105
We present simultaneous infrared and X-ray observations of the Galactic
microquasar GRS 1915+105 using the Palomar 5-m telescope and Rossi X-ray Timing
Explorer on July 10, 1998 UT. Over the course of 5 hours, we observed 6 faint
infrared (IR) flares with peak amplitudes of mJy and durations
of seconds. These flares are associated with X-ray
soft-dip/soft-flare cycles, as opposed to the brighter IR flares associated
with X-ray hard-dip/soft-flare cycles seen in August 1997 by Eikenberry et al.
(1998). Interestingly, the IR flares begin {\it before} the X-ray oscillations,
implying an ``outside-in'' origin of the IR/X-ray cycle. We also show that the
quasi-steady IR excess in August 1997 is due to the pile-up of similar faint
flares. We discuss the implications of this flaring behavior for understanding
jet formation in microquasars.Comment: 10 pages, 4 figures Accepted for publication in ApJ Letter
Recent Assembly of an Imprinted Domain from Non-Imprinted Components
Genomic imprinting, representing parent-specific expression of alleles at a locus, raises many questions about how—and especially why—epigenetic silencing of mammalian genes evolved. We present the first in-depth study of how a human imprinted domain evolved, analyzing a domain containing several imprinted genes that are involved in human disease. Using comparisons of orthologous genes in humans, marsupials, and the platypus, we discovered that the Prader-Willi/Angelman syndrome region on human Chromosome 15q was assembled only recently (105–180 million years ago). This imprinted domain arose after a region bearing UBE3A (Angelman syndrome) fused with an unlinked region bearing SNRPN (Prader-Willi syndrome), which had duplicated from the non-imprinted SNRPB/B′. This region independently acquired several retroposed gene copies and arrays of small nucleolar RNAs from different parts of the genome. In their original configurations, SNRPN and UBE3A are expressed from both alleles, implying that acquisition of imprinting occurred after their rearrangement and required the evolution of a control locus. Thus, the evolution of imprinting in viviparous mammals is ongoing
Integrated assessment of the food-water-land-ecosystems nexus in Europe:Implications for sustainability
Climate and socio-economic change impacts are likely to cross traditional sectoral and regional boundaries with cascading indirect, and potentially far-reaching, repercussions. This is particularly important for the food-water-land-ecosystems (FWLE) nexus, which is fundamental for the achievement of at least six of the seventeen Sustainable Development Goals (SDGs). A holistic understanding of the FWLE nexus interactions and how and to what extent various exogenous drivers of change affect them is therefore central to cross-sectoral adaptation planning. Here, we present such an integrated assessment for Europe applying a regional Integrated Assessment Platform (IAP). The study explores a wide range of future climate and socio-economic scenarios using more than 900 model simulations. The results show that food production is likely to be the main driver of Europe's future landscape change dynamics (with or without climate change). Agriculture and land use allocation is often driven by complex cross-sectoral interactions with cascading effects on other sectors such as forestry, biodiversity, and water under the various scenarios. The modelling also highlighted that while sustaining current levels of food production at the European level could be achievable under most climate and socio-economic scenarios, there are significant regional differences with winners and losers. The analysis raises the question of whether current production and consumption policies are sustainable in the long-term. Such systematic integrated model-based analysis plays a crucial role in informing development of cross-sectoral policies that maximise synergies and minimise trade-offs across nexus sectors, regions, and scenarios. This is essential to achieve the SDGs
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