487 research outputs found

    'Do the resilient things.' Residents' perspectives on responsibilities for flood risk adaptation in England

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    Residents should take adaptive action to reduce flood risk – this claim increasingly resonates in the academic debate on flood risk management (FRM). Hence it must be assumed that a change in the division of responsibilities between actors involved is an imperative, i.e., beyond the public authorities, residents should become more responsible for their own flood resilience. However, residents’ perspectives on their own and other’s responsibility for adaptive action has not yet been explored extensively. In this contribution, we distinguish between four notions of responsibility in analysing the perspectives of residents regarding flood risk adaptation measures undertaken by public authorities, insurance companies and residents themselves. A qualitative study in England shows how residents perceive responsibilities for flood risk adaptation across the various notions and actors, including themselves. We found that residents have clear expectations and perceptions on how they think responsibility is divided among stakeholders and how they would like it to be. Additionally, the discourse on responsibility division in FRM raises questions and causes mismatches between the formal legal parameters and residents’ perceptions. With the insights into residents’ perceptions, opportunities arise to better inform and encourage them to take flood risk adaptation measures and thereby improve flood resilience

    Migration aspirations and migration cultures:A case study of Ukrainian migration towards the European Union

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    An abundant body of research focused on macrolevel, mesolevel, and microlevel factors explaining why individuals move across international borders. In this paper, we aim to complement the existing literature by exploring how, within a single country, mesolevel factors differently impact migration aspirations, focusing on a case study of Ukraine. We particularly focus on how migration aspirations of individuals in two different regions can be explained by their international social networks with family members, on the one hand, and with friends, on the other. Furthermore, we explore whether regional migration characteristics play a role, as well as the interaction of such characteristics with individuals' frequency of contact with transnational networks. Our analyses are based on the EUMAGINE project and suggest that the interplay between regional migration characteristics and transnational social contact are key for explainingthe decline of migration systems over time

    OGtree: a tool for creating genome trees of prokaryotes based on overlapping genes

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    OGtree is a web-based tool for constructing genome trees of prokaryotic species based on a measure of combining overlapping-gene content and overlapping-gene order in their whole genomes. The overlapping genes (OGs) are defined as adjacent genes whose coding sequences overlap partially or entirely. In fact, OGs are ubiquitous in microbial genomes and more conserved between species than non-OGs. Based on these properties, it has been suggested that OGs can serve as better phylogenetic characters than non-OGs for reconstructing the evolutionary relationships among microbial genomes. OGtree takes the accession numbers of prokaryotic genomes as its input. It then downloads their complete genomes from the National Centre for Biotechnology Information and identifies OGs in each genome and their orthologous OGs in other genomes. Next, OGtree computes an overlapping-gene distance between each pair of input genomes based on a combination of their OG content and orthologous OG order. Finally, it utilizes distance-based methods of building tree to reconstruct the genome trees of input prokaryotic genomes according to their pairwise OG distance. OGtree is available online at http://bioalgorithm.life.nctu.edu.tw/OGtree/

    Class Position of Immigrant Workers in a Post-Industrial Economy: The Dutch Case

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    In this paper, the issue of changing labour-market opportunities and the position of members of minority groups in advanced service economies is addressed, focusing on the Dutch case. We distinguish between two social hierarchies, one of traditional ‘fordist’ occupations and one of post-fordist occupations. Compared to the native Dutch, all immigrant groups are over-represented at the bottom of the labour market, both in the fordist and in the postindustrial hierarchy. Increased immigrant labour-market participation in the 1990s was accompanied by a strong rise in the number of flexible labour contracts. Native Dutch also work more frequently on flexible labour contracts, but not to the same extent as immigrants. The lower occupational level of the Surinamese, Antilleans and other non-Western immigrants employed in post-industrial occupations can be attributed to their low educational level. This is not true, however, for Turks, Moroccans and other non-Western immigrants employed in fordist occupations. Their low occupational level can not be completely explained by their low educational level. The effects of changes in the economic structure differ for ethnic groups, depending on their past employment, their cultural capital and the institutional framework in which they have to operate

    Biodegradable Poly(2-Dimethylamino Ethylamino)Phosphazene for In Vivo Gene Delivery to Tumor Cells. Effect of Polymer Molecular Weight

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    Purpose. Previously, we have shown that complexes of plasmid DNA with the biodegradable polymer poly(2-dimethylamino ethylamino)phosphazene (p(DMAEA)-ppz) mediated tumor selective gene expression after intravenous administration in mice. In this study, we investigated the effect of p(DMAEA)-ppz molecular weight on both in vitro and in vivo tumor transfection, as well as on complex induced toxicity. Materials and Methods. p(DMAEA)-ppz with a broad molar mass distribution was fractionated by preparative size exclusion chromatography. Polyplexes consisting of plasmid DNA and the collected polymer fractions were tested for biophysical properties, (cyto)toxicity and transfection activity. Results. Four p(DMAEA)-ppz fractions were collected with weight average molecular weights ranging from 130 to 950 kDa, and with narrow molecular mass distributions (Mw/Mn from 1.1 to 1.3). At polymer-to-DNA (N/P) ratios above 6, polyplexes based on these polymers were all positively charged (zeta potential 25–29 mV), and had a size of 80–90 nm. The in vitro cytotoxicity of the polyplexes positively correlated with polymer molecular weight. The in vitro transfection activity of the different polyplexes depended on their N/P ratio, and was affected by the degree of cytotoxicity, as well as the colloidal stability of the different polyplexes. Intravenous administration of polyplexes based on the high molecular weight polymers led to apparent toxicity, as a result of polyplex-induced erythrocyte aggregation. On the other hand, administration of polyplexes based on low molecular weight p(DMAEA)-ppz_s (Mw130 kDa) did not show signs of toxicity and resulted in tumor selective gene expression. Conclusion. Polymer molecular weight fractionation enabled us to optimize the transfection efficiency/ toxicity ratio of p(DMAEA)-ppz polyplexes for in vitro and in vivo tumor transfection. KEY WORDS: biodegradable; cationic polymer; DNA; molecular weight; tumor gene delivery

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    The nucleation and growth of a calcium phosphate (Ca-P) coating deposited on titanium implants from simulated body fluid was investigated by using atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM). Forty titanium alloy plates were assigned into two groups. One group with a smooth surface having a maximum roughness Rmax<0.10 μm (s-Ti6Al4V) and a group with a rough surface with an Rmax<0.25 μm (r-Ti6Al4V) were used. Titanium samples were immersed in SBF concentrated by five (SBF×5) from 10 min to 5 h and examined by AFM and ESEM. Scattered Ca-P deposits of approximately 15 nm in diameter appeared after only 10 min of immersion in SBF×5. These Ca-P deposits grew up to 60–100 nm after 4 h on both s- and r-Ti6Al4V substrates. With increasing immersion time, the packing of Ca-P deposits with size of tens of nanometers in diameter formed larger globules and then a continuous Ca-P film on titanium substrates. A direct contact between the Ca-P coating and the Ti6Al4V surface was observed. The Ca-P coating was composed of nanosized deposits and of an interfacial glassy matrix. This interfacial glassy matrix might ensure the adhesion between the Ca-P coating and the Ti6Al4V substrate. In the case of s-Ti6Al4V substrate, failures within this interfacial glassy matrix were observed overtime. Part of the glassy matrix remained on s-Ti6Al4V while part detached with the Ca-P film. The Ca-P coating detached from the smooth substrate, whereas the Ca-P film extended onto the whole rough titanium surface over time. In the case of r-Ti6Al4V, the Ca-P coating covered evenly the substrate after immersion in SBF×5 for 5 h. The present study suggested that the heterogeneous nucleation of Ca-P on titanium was immediate and did not depend on the Ti6Al4V surface topography. The further growth and mechanical attachment of the final Ca-P coating strongly depended on the surface, for which a rough topography was beneficial

    Detection of Biochemical Pathways by Probabilistic Matching of Phyletic Vectors

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    A phyletic vector, also known as a phyletic (or phylogenetic) pattern, is a binary representation of the presences and absences of orthologous genes in different genomes. Joint occurrence of two or more genes in many genomes results in closely similar binary vectors representing these genes, and this similarity between gene vectors may be used as a measure of functional association between genes. Better understanding of quantitative properties of gene co-occurrences is needed for systematic studies of gene function and evolution. We used the probabilistic iterative algorithm Psi-square to find groups of similar phyletic vectors. An extended Psi-square algorithm, in which pseudocounts are implemented, shows better sensitivity in identifying proteins with known functional links than our earlier hierarchical clustering approach. At the same time, the specificity of inferring functional associations between genes in prokaryotic genomes is strongly dependent on the pathway: phyletic vectors of the genes involved in energy metabolism and in de novo biosynthesis of the essential precursors tend to be lumped together, whereas cellular modules involved in secretion, motility, assembly of cell surfaces, biosynthesis of some coenzymes, and utilization of secondary carbon sources tend to be identified with much greater specificity. It appears that the network of gene coinheritance in prokaryotes contains a giant connected component that encompasses most biosynthetic subsystems, along with a series of more independent modules involved in cell interaction with the environment
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