385 research outputs found
Shells of crystal field symmetries evidenced in oxide nano-crystals
By the use of a point charge model based on the Judd-Ofelt transition theory,
the luminescence from Eu3+ ions embedded in Gd2O3 clusters is calculated and
compared to the experimental data. The main result of the numerical study is
that without invoking any other mechanisms such as crystal disorder, the pure
geometrical argument of the symmetry breaking induced by the particle surface
has influence on the energy level splitting. The modifications are also
predicted to be observable in realistic conditions where unavoidable size
dispersion has to be taken into account. The emission spectrum results from the
contribution of three distinct regions, a cluster core, a cluster shell and a
very surface, the latter being almost completely quenched in realistic
conditions. Eventually, by detailing the spectra of the ions embedded at
different positions in the cluster we get an estimate of about 0.5 nm for the
extent of the crystal field induced Stark effect. Due to the similarity between
Y2O3 and Gd2O3, these results apply also to Eu3+ doped Y2O3 nanoparticles
The evaluation of the Paris declaration on aid effectiveness: what does it tell us? What results for the health sector?
Five years after the signing of the Paris Declaration on aid effectiveness by donors and developing countries, there is a climate of high expectations about the results achieved and the impact at sector level. Several evaluations and monitoring surveys have been conducted by the OECD to measure progress made so far in implementing the principles of ownership, alignment, harmonisation, results and mutual accountability. For the health sector, results have also been documented in the context of the International Health Partnership (IHP+). We critically reviewed all the aid effectiveness surveys and evaluations published since 2005 by the OECD and IHP+ so as to analyse what results have been achieved so far as well as the relevance of the frameworks used. To date, results of the implementation of the Paris Declaration are mixed. In the health sector, good progress has been achieved in terms of country ownership and coordination, while alignment and use of country systems, managing for results and mutual accountability lag behind. However, the results recorded often reflect different interpretation of the indicators depending on the respondent, the data available or the time of the survey. Making generalisations is therefore difficult and comparisons between country surveys and over time may not be appropriate. Linking progress in aid effectiveness with improvements in health outcomes is also controversial. Results from the evaluations of the Paris Declaration should be used with caution in the current debate about aid effectiveness. What do the indicators used actually tell us? How realistically can aggregated scores reflect complex issues such as aid effectiveness in different countries, by different donors and over time? Improved evaluation is clearly needed. Data collection should be more rigorous and at sector level contextual factors and behaviour change should be better assessed, over a longer term and through more qualitative comprehensive methods.GRAP-PA Sant
Moments analysis in Markov reward models
We analyze the moments of the accumulated reward over the interval (0, t) in a continuous-time Markov chain. We develop a numerical procedure to efficiently compute the normalized moments using the uniformization technique. Our algorithm involves auxiliary quantities whose convergence is analyzed, and for which we provide a probabilistic interpretation
Access to medicines from a health system perspective
Most health system strengthening interventions ignore interconnections between systems components. In particular, complex relationships between medicines and health financing, human resources, health information and service delivery are not given sufficient consideration. As a consequence, populations' access to medicines (ATM) is addressed mainly through fragmented, often vertical approaches usually focusing on supply, unrelated to the wider issue of access to health services and interventions. The objective of this article is to embed ATM in a health system perspective. For this purpose, we perform a structured literature review: we examine existing ATM frameworks, review determinants of ATM and define at which level of the health system they are likely to occur; we analyse to which extent existing ATM frameworks take into account access constraints at different levels of the health system. Our findings suggest that ATM barriers are complex and interconnected as they occur at multiple levels of the health system. Existing ATM frameworks only partially address the full range of ATM barriers. We propose three essential paradigm shifts that take into account complex and dynamic relationships between medicines and other components of the health system. A holistic view of demand-side constraints in tandem with consideration of multiple and dynamic relationships between medicines and other health system resources should be applied; it should be recognized that determinants of ATM are rooted in national, regional and international contexts. These are schematized in a new framework proposing a health system perspective on AT
YAG nano-light sources with high Ce concentration
We investigate the luminescence properties of 10 nm YAG nanoparticles doped
with Ce ions at 0.2%, 4% and 13% that are designed as active probes for
Scanning Near field Optical Microscopy. They are produced by a physical method
without any subsequent treatment, which is imposed by the desired application.
The structural analysis reveals the amorphous nature of the particles, which we
relate to some compositional defect as indicated by the elemental analysis. The
optimum emission is obtained with a doping level of 4%. The emission of the YAG
nanoparticles doped at 0.2% is strongly perturbed by the crystalline disorder
whereas the 13% doped particles hardly exhibit any luminescence. In the latter
case, the presence of Ce4+ ions is confirmed, indicating that the Ce
concentration is too high to be incorporated efficiently in YAG nanoparticles
in the trivalent state. By a unique procedure combining cathodoluminescence and
Rutherford backscattering spectrometry, we demonstrate that the enhancement of
the particles luminescence yield is not proportional to the doping
concentration, the emission enhancement being larger than the Ce concentration
increase. Time-resolved photoluminescence reveals the presence of quenching
centres likely related to the crystalline disorder as well as the presence of
two distinct Ce ions populations. Eventually, nano-cathodoluminescence
indicates that the emission and therefore the distribution of the doping Ce
ions and of the defects are homogeneous
Sumoylation delays the ATF7 transcription factor subcellular localization and inhibits its transcriptional activity
Over the past few years, small ubiquitin-like modifier (SUMO) modification has emerged as an important regulator of diverse pathways and activities including protein localization and transcriptional regulation. We identified a consensus sumoylation motif (IKEE), located within the N-terminal activation domain of the ATF7 transcription factor and thus investigated the role of this modification. ATF7 is a ubiquitously expressed transcription factor, homologous to ATF2, that binds to CRE elements within specific promoters. This protein is able to heterodimerize with Jun or Fos proteins and its transcriptional activity is mediated by interaction with TAF12, a subunit of the general transcription factor TFIID. In the present article, we demonstrate that ATF7 is sumoylated in vitro (using RanBP2 as a E3-specific ligase) and in vivo. Moreover, we show that ATF7 sumoylation affects its intranuclear localization by delaying its entry into the nucleus. Furthermore, SUMO conjugation inhibits ATF7 transactivation activity by (i) impairing its association with TAF12 and (ii) blocking its binding-to-specific sequences within target promoters
Cumulative dietary risk characterisation of pesticides that have chronic effects on the thyroid
A retrospective chronic cumulative risk assessment of dietary exposure to pesticide residues, supported by an uncertainty analysis based on expert knowledge elicitation, was conducted for two effects on the thyroid, hypothyroidism and parafollicular cell (C‐cell) hypertrophy, hyperplasia and neoplasia. The pesticides considered in this assessment were identified and characterised in the scientific report on the establishment of cumulative assessment groups of pesticides for their effects on the thyroid. Cumulative exposure assessments were conducted through probabilistic modelling by EFSA and the Dutch National Institute for Public Health and the Environment (RIVM) using two different software tools and reported separately. These exposure assessments used monitoring data collected by Member States under their official pesticide monitoring programmes in 2014, 2015 and 2016 and individual consumption data from 10 populations of consumers from different countries and different age groups. This report completes the characterisation of cumulative risk, taking account of the available data and the uncertainties involved. For each of the 10 populations, it is concluded with varying degrees of certainty that cumulative exposure to pesticides that have the chronic effects on the thyroid mentioned above does not exceed the threshold for regulatory consideration established by risk managers
What results can be expected from the agenda for aid effectiveness?
Introduction: Currently there is a climate of high expectations with regard to producing demonstrable results of aid effectiveness in the health sector. Yet, commitments to aid effectiveness have only partially been implemented so far. Existing evaluation frameworks developed in the context of the Paris Declaration and International Health Partnership (IHP+) are not sufficiently geared toward whether and how practices have changed at donor, central and operational levels, and thus how reforms have actually been implemented. Measuring their impact also presents methodological challenges.
Methods: This communication aims to present an outline of how to measure results from the agenda for aid effectiveness. It argues that it should be carried out at three levels. A first, critical step for evaluating the results from the Paris Declaration and IHP+ is to evaluate its implementation process and the direct effects it has had on changes in behaviour for all stakeholders (donors, government, service providers, etc.). A second level of evaluation is to assess how far donor support and implementation of Paris principles have contributed to health system strengthening (HSS) up to the level of service delivery. The third level where improvement is expected and should be measured is at health outcome/status level. Qualitative methods can help to understand what constraining factors are, what reforms have led to improvements and why, and finally the impact on population health.
Results: This three-level assessment was made in Mali. We found that some progress and positive changes have been observed in recent years that can be attributed to the agenda for aid effectiveness; outcome and impact indicators have also improved in the past years. However, donors have not fulfilled all their commitments.
Conclusion: Whilst changes in behaviour and practices are occurring, adherence to the principles of aid effectiveness is far from complete, thus expectations should be realistic.GRAP-PA Sant
Cost-effectiveness of Algorithms for Confirmation Test of Human African Trypanosomiasis
Algorithms that incorporate concentration techniques are more effective and efficient than the currently used algorithms
Effect on public health of a possible increase of the maximum level for ‘aflatoxin total’ from 4 to 10 μg/kg in peanuts and processed products thereof, intended for direct human consumption or use as an ingredient in foodstuffs
The Panel wishes to thank the EFSA staff members: Davide Arcella and Valentina Bocca for the support provided to this scientific output. The CONTAM Panel acknowledges all European competent institutions and other stakeholders that provided occurrence data on aflatoxins in peanut, peanut butter and peanut oil, and supported the data collection for the Comprehensive European Food Consumption Database. Adopted: 23 January 2018Peer reviewedPublisher PD
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