115 research outputs found
Effects of technetium on marine micro-organisms
Eleven bacterial species have been isolated from the upper layer of intertidal sediments collected along the Belgian coast (Coxyde). Three of them (no. 1, 4 and 11) have been chosen for their halophilous character. One species has been identified as Flavobacterium halmephilum, the other two are being investigated. Effects of technetium (99Tc) have been studied on a mixed bacterial population isolated from sediments, as well as on the three halophilic species.At the concentrations utilized in this work (up to 100 microg ml-1), 99Tc has no evident effects on bacterial growth. Uptake of technetium (99Tc and/or 95mTc) has been investigated in the mixed bacterial population, in the three halophilic bacteria (including Flavobacterium halmephilum) and in the benthic ciliate Uronema marinum. It has been found that technetium is taken up by all these micro-organisms. However, the transfer factor (TF) in bacteria may vary considerably (from 0.5 to 200), but the cause of this variability is not known and deserves further study.The ciliate Uronema marinum, which feeds on living marine bacteria, was found to take up 95mTc added to the culture medium. However, the TF in this ciliate is rather low (from 1.4 to 5.5). Because it feeds on bacteria, Uronema marinum is supposed to take up technetium from water (direct contamination) as well as from contaminated bacteria (indirect contamination). Experiments with 95mTc-labeled bacterial cells might be useful, as they could indicate which form of contamination (direct or indirect) is prevailing
Indirect study of 19Ne states near the 18F+p threshold
The early E < 511 keV gamma-ray emission from novae depends critically on the
18F(p,a)15O reaction. Unfortunately the reaction rate of the 18F(p,a)15O
reaction is still largely uncertain due to the unknown strengths of low-lying
proton resonances near the 18F+p threshold which play an important role in the
nova temperature regime. We report here our last results concerning the study
of the d(18F,p)19F(alpha)15N transfer reaction. We show in particular that
these two low-lying resonances cannot be neglected. These results are then used
to perform a careful study of the remaining uncertainties associated to the
18F(p,a)15O and 18F(p,g)19Ne reaction rates.Comment: 18 pages, 8 figures. Accepted in Nuclear Physics
The key to bringing DNA collections to the next level
DNA collections are a valuable type of Natural Science collection, enabling the validation of past research, serving as a source for new genomic studies and supporting ex situ conservation. The DiSSCo Flanders DNA collection working group, aiming to advance and "unlock" their DNA collections, identified the need for: 1) actively sharing best practices regarding the management of DNA collections; and 2) providing guidance on how to bring theory into practice. By combining best practice examples from within the working group with available literature and brainstorming ideas, the working group co-created two outputs, referred to as: the "Challenges" and the "Key". The Challenges are a list of obstacles to DNA collection management, which shape the structure of the linked Key and can also be used to spark discussion amongst stakeholders. The Key is a tool that guides users through the maturation process of their DNA collection in a standardised way. It stimulates holistic growth, breaks down the needed work into manageable steps and helps to decide priorities during the process. Furthermore, the Key facilitates communication with both internal stakeholders and external DNA collection managers. The Key distinguishes itself from other self-assessment tools in several ways: it includes (re)investigation of the collection s purpose and context; it is specialised for DNA collections; it delivers concrete goals linked to relevant information and shared experience; and it is inclusive, targeting all Natural Science DNA collections, regardless of their context or size
Wealthiest is Not Always Healthiest: What Explains Differences in Child Mortality in West Africa?
The Long Shadow of History. Roman Legacy and Economic Development -- Evidence from the German Limes
Documentation FiFoSiM: Integrated Tax Benefit Microsimulation and CGE Model
ABSTRACT: This paper describes FiFoSiM, the integrated tax benefit microsimulation and computable general equilibrium (CGE) model of the Center of Public Economics at the University of Cologne. FiFoSiM consists of three main parts. The first part is a static tax benefit microsimulation module. The second part adds a behavioural component to the model: an econometrically estimated labour supply model. The third module is a CGE model which allows the user of FiFoSiM to assess the global economic effects of policy measures. Two specific features distinguish FiFoSiM from other tax benefit models: First, the simultaneous use of two databases for the tax benefit module and second, the linkage of the tax benefit model to a CGE model
Middle Class in Africa: Determinants and Consequences
This study complements the inclusive growth literature by examining the determinants and consequences of the middle class in a continent where economic growth has been relatively high. The empirical evidence is based on a sample of 33 African countries for a 2010 cross-sectional study. OLS, 2SLS, 3SLS and SUR estimation techniques are employed to regress a plethora of middle class indicators, notably, the: floating, middle-class with floating, middle-class without floating, lower-middle-income and upper-middle-income categories. Results can be classified into two main strands. First, results on determinants broadly show that GDP per capita and education positively affect all middle class dependent variables. However, we have seen a negative nexus for the effect of ethnic fragmentation, political stability in general and partially for economic vulnerability. Simple positive correlations have been observed for: the size of the informal sector, openness and democracy. Second, on the consequences, the middle class enables the accumulation of human and infrastructural capital, while its effect is null on political stability and democracy in the short-run but positive for governance and modernisation. Policy implications are discussed
Identification of novel risk loci for restless legs syndrome in genome-wide association studies in individuals of European ancestry : a meta-analysis
Background Restless legs syndrome is a prevalent chronic neurological disorder with potentially severe mental and physical health consequences. Clearer understanding of the underlying pathophysiology is needed to improve treatment options. We did a meta-analysis of genome-wide association studies (GWASs) to identify potential molecular targets. Methods In the discovery stage, we combined three GWAS datasets (EU-RLS GENE, INTERVAL, and 23andMe) with diagnosis data collected from 2003 to 2017, in face-to-face interviews or via questionnaires, and involving 15126 cases and 95 725 controls of European ancestry. We identified common variants by fixed-effect inverse-variance meta-analysis. Significant genome-wide signals (p Findings We identified and replicated 13 new risk loci for restless legs syndrome and confirmed the previously identified six risk loci. MEIS1 was confirmed as the strongest genetic risk factor for restless legs syndrome (odds ratio 1.92, 95% CI 1 85-1.99). Gene prioritisation, enrichment, and genetic correlation analyses showed that identified pathways were related to neurodevelopment and highlighted genes linked to axon guidance (associated with SEMA6D), synapse formation (NTNG1), and neuronal specification (HOXB cluster family and MYT1). Interpretation Identification of new candidate genes and associated pathways will inform future functional research. Advances in understanding of the molecular mechanisms that underlie restless legs syndrome could lead to new treatment options. We focused on common variants; thus, additional studies are needed to dissect the roles of rare and structural variations.Peer reviewe
Blind Spots on the Map of Aid Allocations, Concentration and Complementarity of International NGO Aid
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