336 research outputs found
Comparing Extreme Rainfall and Large-Scale Flooding Induced Inundation Risk – Evidence from a Dutch Case-Study
Increasing flood exposure in the Netherlands: implications for risk financing
The effectiveness of disaster risk management and financing mechanisms
depends on an accurate assessment of current and future hazard exposure. The
increasing availability of detailed data offers policy makers and the
insurance sector new opportunities to understand trends in risk, and to make
informed decisions on ways to deal with these trends. In this paper we show
how comprehensive property level information can be used for the assessment
of exposure to flooding on a national scale, and how this information
provides valuable input to discussions on possible risk financing practices.
The case study used is the Netherlands, which is one of the countries most
exposed to flooding globally, and which is currently undergoing a debate on
strategies for the compensation of potential losses. Our results show that
flood exposure has increased rapidly between 1960 and 2012, and that the
growth of the building stock and its economic value in flood-prone areas has
been higher than in non-flood-prone areas. We also find that property values
in flood-prone areas are lower than those in non-flood-prone areas. We argue
that the increase in the share of economic value located in potential flood-prone
areas can have a negative effect on the feasibility of private
insurance schemes in the Netherlands. The methodologies and results
presented in this study are relevant for many regions around the world where
the effects of rising flood exposure create a challenge for risk financing
Prediction of a deletion copy number variant by a dense SNP panel
<p>Abstract</p> <p>Background</p> <p>A newly recognized type of genetic variation, Copy Number Variation (CNV), is detected in mammalian genomes, e.g. the cattle genome. This form of variation can potentially cause phenotypic variation. Our objective was to determine whether dense SNP (single nucleotide polymorphisms) panels can capture the genetic variation due to a simple bi-allelic CNV, with the prospect of including the effect of such structural variations into genomic predictions.</p> <p>Methods</p> <p>A deletion type CNV on bovine chromosome 6 was predicted from its neighboring SNP with a multiple regression model. Our dataset consisted of CNV genotypes of 1,682 cows, along with 100 surrounding SNP genotypes. A prediction model was fitted considering 10 to 100 surrounding SNP and the accuracy obtained directly from the model was confirmed by cross-validation.</p> <p>Results and conclusions</p> <p>The accuracy of prediction increased with an increasing number of SNP in the model and the predicted accuracies were similar to those obtained by cross-validation. A substantial increase in accuracy was observed when the number of SNP increased from 10 to 50 but thereafter the increase was smaller, reaching the highest accuracy (0.94) with 100 surrounding SNP. Thus, we conclude that the genotype of a deletion type CNV and its putative QTL effect can be predicted with a maximum accuracy of 0.94 from surrounding SNP. This high prediction accuracy suggests that genetic variation due to simple deletion CNV is well captured by dense SNP panels. Since genomic selection relies on the availability of a dense marker panel with markers in close linkage disequilibrium to the QTL in order to predict their genetic values, we also discuss opportunities for genomic selection to predict the effects of CNV by dense SNP panels, when CNV cause variation in quantitative traits.</p
Mouse models of ageing and their relevance to disease
Ageing is a process that gradually increases the organism’s vulnerability to death. It affects different biological pathways, and the underlying cellular mechanisms are complex. In view of the growing disease burden of ageing populations, increasing efforts are being invested in understanding the pathways and mechanisms of ageing. We review some mouse models commonly used in studies on ageing, highlight the advantages and disadvantages of the different strategies, and discuss their relevance to disease susceptibility. In addition to addressing the genetics and phenotypic analysis of mice, we discuss examples of models of delayed or accelerated ageing and their modulation by caloric restriction
Rare case of an adult male Montagu's Harrier Circus pygargus over-summering in West Africa, as revealed by GPS tracking
Over-summering within or near the African wintering range by immature, non-breeding individuals occurs regularly in several species of long-distance migratory raptors, yet the extent of over-summering in Africa by adult birds remains unclear. In this study, we describe a case of an adult Montagu's Harrier over-summering in Africa, as revealed by GPS tracking. By relating detailed knowledge of the bird's movements to remotely sensed environmental data (normalized difference vegetation index, NDVI), we show that over-summering in this case was likely related to an exceptionally difficult breeding season the previous year rather than an effect of adverse weather conditions encountered during the winter or a failed attempt to migrate. Various factors are discussed as potential driving forces behind the bird's intra-African movements. Finally, we relate the documented case to a large number of North European Montagu's Harriers studied by telemetry and show that over-summering in Africa by adult individuals is indeed a rare event
Cosmological Particle Creation in the Presence of Lorentz Violation
In recent years, the effects of Lorentz symmetry breaking in cosmology has
attracted considerable amount of attention. In cosmological context several
topics can be affected by Lorentz violation,e.g., inflationary scenario, CMB,
dark energy problem and barryogenesis. In this paper we consider the
cosmological particle creation due to Lorentz violation (LV). We consider an
exactly solvable model for finding the spectral properties of particle creation
in an expanding space-time exhibiting Lorentz violation. In this model we
calculate the spectrum and its variations with respect to the rate and the
amount of space-time expansion.Comment: 6 pages, 6 figures, To appear in Physics Letters
Economic Impacts of Irrigation-Constrained Agriculture in the Lower Po Basin
Climate change, increasing demand for water, higher environmental standards and inelastic water supply suggest that future drought response in Southern Europe would require more efficient management of water use. In this context, there is a pressing need for a better understanding of the economic impacts of irrigation restrictions, including their microeconomic and broad economic repercussions. This paper connects a multi-attribute Revealed Preference Model working at an agricultural district level with a regionally calibrated supply and use model that combines nonlinear programming and input-output modeling techniques to address water allocation issues. To the best of our knowledge, this is the first time these two modeling approaches are combined in this fashion. Methods are illustrated with an application to the Lower Po River Basin (LPRB) in the Emilia Romagna Region, Italy. Results show that irrigation restrictions generate rising incremental losses in the agricultural districts of the LPRB, which are amplified through negative inter-sectorial feedbacks at a regional level. Contraction of production in Emilia Romagna results in an excess demand situation that propels the production of substitute goods elsewhere in Italy, partially but not fully compensating economic losses in the region. Methods and results offer a basis for assessing tradeoffs in irrigation restrictions and related adaptations, for climate change included
Inflationary Reheating in Grand Unified Theories
Grand unified theories may display multiply interacting fields with strong
coupling dynamics. This poses two new problems: (1) What is the nature of
chaotic reheating after inflation, and (2) How is reheating sensitive to the
mass spectrum of these theories ? We answer these questions in two interesting
limiting cases and demonstrate an increased efficiency of reheating which
strongly enhances non-thermal topological defect formation, including monopoles
and domain walls. Nevertheless, the large fluctuations may resolve this
monopole problem via a modified Dvali-Liu-Vachaspati mechanism in which
non-thermal destabilsation of discrete symmetries occurs at reheating.Comment: 4 pages, 5 ps figures - 1 colour, Revtex. Further (colour & 3-D)
figures available from http://www.sissa.it/~bassett/reheating/ . Matched to
version to appear in Phys. Rev. let
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