369 research outputs found

    DESORPTION BEHAVIOUR OF POLYCYCLIC AROMATIC HYDROCARBONS IN HARBOUR SLUDGE FROM THE PORT OF ROTTERDAM, THE NETHERLANDS

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    Abstract. Desorption of eight polycyclic aromatic hydrocarbons (PAH) from two harbour sludges from the Port of Rotterdam, the Netherlands, was studied by column elution experiments. When water moves in a sludge layer desorbing contaminants like PAH can be dispersed in the environment. Separation of liquid and solid phase in batches of sludge, stored for more than three years, by ultra-centrifugation at 4 • C yielded equilibrium partition coefficients. Temperature effects could not account for the observed differences with reported literature values. The differences are attributed to the contact time of PAH in the sediment. Laboratory data reported in the literature were often obtained after short contact times and therefore may not represent equilibrium partitioning. Our values represent contact times in excess of three years and are therefore more representative for the field conditions. Partition coefficients obtained from column elution experiments were slightly above those obtained from the batch experiments. During column elution of the sludge from the Beneden Merwede sorption equilibrium was absent for the lighter compounds. This is attributed to the presence of a large portion of immobile water in the columns. Elution in the Beerkanaal columns occurred at near sorption equilibrium although pore water velocities were higher. Assuming that desorption is diffusion controlled, observed desorption in both materials could be explained. The non-equilibrium desorption in the Beneden Merwede sludge for phenanthrene, and to a lesser extent for anthracene and fluoranthene, could be described by a diffusion limited model assuming spherical particles

    Centre-specific bacterial pathogen typing affects infection-control decision making

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    Whole-genome sequencing is becoming the de facto standard for bacterial outbreak surveillance and infection prevention. This is accompanied by a variety of bioinformatic tools and needs bioinformatics expertise for implementation. However, little is known about the concordance of reported outbreaks when using different bioinformatic workflows. In this multi-centre proficiency testing among 13 major Dutch healthcare-affiliated centres, bacterial whole-genome outbreak analysis was assessed. Centres who participated obtained two randomized bacterial datasets of Illumina sequences, a Klebsiella pneumoniae and a Vancomycin-resistant Enterococcus faecium, and were asked to apply their bioinformatic workflows. Centres reported back on antimicrobial resistance, multi-locus sequence typing (MLST), and outbreak clusters. The reported clusters were analysed using a method to compare landscapes of phylogenetic trees and calculating Kendall–Colijn distances. Furthermore, fasta files were analysed by state-of-the-art single nucleotide polymorphism (SNP) analysis to mitigate the differences introduced by each centre and determine standardized SNP cut-offs. Thirteen centres participated in this study. The reported outbreak clusters revealed discrepancies between centres, even when almost identical bioinformatic workflows were used. Due to stringent filtering, some centres failed to detect extended-spectrum beta-lactamase genes and MLST loci. Applying a standardized method to determine outbreak clusters on the reported de novo assemblies, did not result in uniformity of outbreak-cluster composition among centres

    Strengths and Weaknesses for Climate Change: Adaptation in Water Governance: A Comparison Across Six European Regions

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    This chapter comparatively analyses the policy and governance contexts of six European regions that are affected by different hydrological impacts of climate change. The results demonstrate that a major governance strength across regions lies in the organization of management capacities to deal with existing water-related risks. For example, the Dutch context focuses on water safety, Cyprus has a clear policy framework to deal with water scarcity and in the Norwegian city of Bergen, wastewater is well managed. As a consequence of this focus on present-day risks, climate adaptation governance also focuses on historical risks. New or exacerbated risks posed by climate change remain largely untreated, and responsibilities for dealing with climate-related risks remain unspecified, as also becomes clear in the German and Spanish cases. A high degree of governmental fragmentation is identified as another point of weakness. Identified most clearly in the Portuguese case but recognizable in all regional contexts, different subdomains of water management are dealt with under separate policies and are governed by different responsible agencies. Consequently, information about current performance of the water system is scattered and coordinative efforts, which are key to developing adaptation strategies, are hampered

    Personality Disorders in Older Adults: Emerging Research Issues

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    Abstract Empirical research focusing on personality disorders (PDs) among older adults is mainly limited to studies on psychometric properties of age-specific personality tests, the age neutrality of specific items/scales, and validation of personality inventories for older adults. We identified only two treatment studies-one on dialectical behavior therapy and one on schema therapy-both with promising results among older patients despite small and heterogeneous populations. More rigorous studies incorporating age-specific adaptations are needed. Furthermore, in contrast to increasing numbers of psychometric studies, the Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 pays little attention to the characteristics of older adults with PDs. Moreover, the constructs "personality change due to another medical condition" and "late-onset personality disorder" warrant further research among older adults. These needs will become even more pressing given the aging society worldwide

    Inside-Out Regulation of ICAM-1 Dynamics in TNF-α-Activated Endothelium

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    Background: During transendothelial migration, leukocytes use adhesion molecules, such as ICAM-1, to adhere to the endothelium. ICAM-1 is a dynamic molecule that is localized in the apical membrane of the endothelium and clusters upon binding to leukocytes. However, not much is known about the regulation of ICAM-1 clustering and whether membrane dynamics are linked to the ability of ICAM-1 to cluster and bind leukocyte integrins. Therefore, we studied the dynamics of endothelial ICAM-1 under non-clustered and clustered conditions. Principal Findings: Detailed scanning electron and fluorescent microscopy showed that the apical surface of endothelial cells constitutively forms small filopodia-like protrusions that are positive for ICAM-1 and freely move within the lateral plane of the membrane. Clustering of ICAM-1, using anti-ICAM-1 antibody-coated beads, efficiently and rapidly recruits ICAM-1. Using fluorescence recovery after photo-bleaching (FRAP), we found that clustering increased the immobile fraction of ICAM-1, compared to non-clustered ICAM-1. This shift required the intracellular portion of ICAM-1. Moreover, biochemical assays showed that ICAM-1 clustering recruited beta-actin and filamin. Cytochalasin B, which interferes with actin polymerization, delayed the clustering of ICAM-1. In addition, we could show that cytochalasin B decreased the immobile fraction of clustered ICAM-1-GFP, but had no effect on non-clustered ICAM-1. Also, the motor protein myosin-II is recruited to ICAM-1 adhesion sites and its inhibition increased the immobile fraction of both non-clustered and clustered ICAM-1. Finally, blocking Rac1 activation, the formation of lipid rafts, myosin-II activity or actin polymerization, but not Src, reduced the adhesive function of ICAM-1, tested under physiological flow conditions. Conclusions: Together, these findings indicate that ICAM-1 clustering is regulated in an inside-out fashion through the actin cytoskeleton. Overall, these data indicate that signaling events within the endothelium are required for efficient ICAM-1-mediated leukocyte adhesio

    High Hemocyte Load Is Associated with Increased Resistance against Parasitoids in Drosophila suzukii, a Relative of D. melanogaster

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    Among the most common parasites of Drosophila in nature are parasitoid wasps, which lay their eggs in fly larvae and pupae. D. melanogaster larvae can mount a cellular immune response against wasp eggs, but female wasps inject venom along with their eggs to block this immune response. Genetic variation in flies for immune resistance against wasps and genetic variation in wasps for virulence against flies largely determines the outcome of any fly-wasp interaction. Interestingly, up to 90% of the variation in fly resistance against wasp parasitism has been linked to a very simple mechanism: flies with increased constitutive blood cell (hemocyte) production are more resistant. However, this relationship has not been tested for Drosophila hosts outside of the melanogaster subgroup, nor has it been tested across a diversity of parasitoid wasp species and strains. We compared hemocyte levels in two fly species from different subgroups, D. melanogaster and D. suzukii, and found that D. suzukii constitutively produces up to five times more hemocytes than D. melanogaster. Using a panel of 24 parasitoid wasp strains representing fifteen species, four families, and multiple virulence strategies, we found that D. suzukii was significantly more resistant to wasp parasitism than D. melanogaster. Thus, our data suggest that the relationship between hemocyte production and wasp resistance is general. However, at least one sympatric wasp species was a highly successful infector of D. suzukii, suggesting specialists can overcome the general resistance afforded to hosts by excessive hemocyte production. Given that D. suzukii is an emerging agricultural pest, identification of the few parasitoid wasps that successfully infect D. suzukii may have value for biocontrol

    Humans and Insects Decide in Similar Ways

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    Behavioral ecologists assume that animals use a motivational mechanism for decisions such as action selection and time allocation, allowing the maximization of their fitness. They consider both the proximate and ultimate causes of behavior in order to understand this type of decision-making in animals. Experimental psychologists and neuroeconomists also study how agents make decisions but they consider the proximate causes of the behavior. In the case of patch-leaving, motivation-based decision-making remains simple speculation. In contrast to other animals, human beings can assess and evaluate their own motivation by an introspection process. It is then possible to study the declared motivation of humans during decision-making and discuss the mechanism used as well as its evolutionary significance. In this study, we combine both the proximate and ultimate causes of behavior for a better understanding of the human decision-making process. We show for the first time ever that human subjects use a motivational mechanism similar to small insects such as parasitoids [1] and bumblebees [2] to decide when to leave a patch. This result is relevant for behavioral ecologists as it supports the biological realism of this mechanism. Humans seem to use a motivational mechanism of decision making known to be adaptive to a heterogeneously distributed resource. As hypothesized by Hutchinson et al. [3] and Wilke and Todd [4], our results are consistent with the evolutionary shaping of decision making because hominoids were hunters and gatherers on food patches for more than two million years. We discuss the plausibility of a neural basis for the motivation mechanism highlighted here, bridging the gap between behavioral ecology and neuroeconomy. Thus, both the motivational mechanism observed here and the neuroeconomy findings are most likely adaptations that were selected for during ancestral times

    Bridging the legitimacy gap—translating theory into practical signposts for legitimate flood risk governance

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    Legitimacy is widely regarded as a founding principle of ‘good’ and effective governance, yet despite intense academic debate and policy discourse, the concept remains conceptually confusing and poorly articulated in practice. To bridge this gap, this research performed an interpretive thematic analysis of academic scholarship across public administration, public policy, law, political science and geography. Three core themes were identified in relation to representative deliberation, procedural and distributive equity and justice, and socio-political acceptability, with numerous sub-themes therein. In an attempt to clarify conceptual confusion, this paper grounds these theoretical debates in the context of flood risk governance where numerous legitimacy dilemmas exist. A number of questions are presented as conceptual ‘sign posts’ to encourage reflexive governance in the future. Thus, more broadly, we assert the importance of bringing legitimacy to the forefront of contemporary flood risk governance discourse and practice, moving beyond the realm of academic reflection

    Elevated risk of infection with SARS-CoV-2 Beta, Gamma, and Delta variants compared with Alpha variant in vaccinated individuals

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    The extent to which severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) break through infection- or vaccine-induced immunity is not well understood. We analyzed 28,578 sequenced SARS-CoV-2 samples from individuals with known immune status obtained through national community testing in the Netherlands from March to August 2021. We found evidence of an increased risk of infection by the Beta (B.1.351), Gamma (P.1), or Delta (B.1.617.2) variants compared with the Alpha (B.1.1.7) variant after vaccination. No clear differences were found between vaccines. However, the effect was larger in the first 14 to 59 days after complete vaccination compared with ≥60 days. In contrast to vaccine-induced immunity, there was no increased risk for reinfection with Beta, Gamma, or Delta variants relative to the Alpha variant in individuals with infection-induced immunity.</p
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