2,410 research outputs found
Addressing inequality in healthy eating among young people at vocational schools:assessing stakeholder engagement in a Whole Health & Whole School Intervention
Charge separation in donor-C60 complexes with real-time Green's functions: The importance of nonlocal correlations
We use the Nonequilibrium Green's Function (NEGF) method to perform real-time
simulations of the ultrafast electron dynamics of photoexcited donor-C60
complexes modeled by a Pariser-Parr-Pople Hamiltonian. The NEGF results are
compared to mean-field Hartree-Fock (HF) calculations to disentangle the role
of correlations. Initial benchmarking against numerically highly accurate
time-dependent Density Matrix Renormalization Group calculations verifies the
accuracy of NEGF. We then find that charge-transfer (CT) excitons partially
decay into charge separated (CS) states if dynamical non-local correlation
corrections are included. This CS process occurs in ~10 fs after
photoexcitation. In contrast, the probability of exciton recombination is
almost 100% in HF simulations. These results are largely unaffected by nuclear
vibrations; the latter become however essential whenever level misalignment
hinders the CT process. The robust nature of our findings indicate that
ultrafast CS driven by correlation-induced decoherence may occur in many
organic nanoscale systems, but it will only be correctly predicted by
theoretical treatments that include time-nonlocal correlations.Comment: 9 pages, 6 figures + supplemental information (4 pages)
The association between seafood intake and fecundability: Analysis from two prospective studies
Background: Seafood is an important source of omega\u20103 fatty acids, which have been associated with improved oocyte quality and embryo morphology in some studies. However, seafood is also a source of persistent organic pollutants and heavy metals, which may adversely affect fecundity. Previous studies of seafood intake and fecundity have generated inconsistent results. Methods: In two prospective cohort studies of 7836 female pregnancy planners from Denmark (Snart Foraeldre, n = 2709) and North America (PRESTO, n = 5127), we evaluated the association of dietary intake of total seafood and marine\u2010sourced long\u2010chain omega\u20103 fatty acids (eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid) with fecundability. Participants completed a baseline questionnaire on sociodemographics, behavioral factors, anthropometrics, and medical history, and a food frequency questionnaire. Pregnancy status was updated bimonthly for up to 12 months or until reported conception. We estimated fecundability ratios (FRs) and 95% confidence intervals (CIs) using proportional probabilities regression models, adjusted for energy intake and other potential confounders. We restricted analyses to women with 646 menstrual cycles of attempt time at enrollment. Results: Intake of total seafood or marine\u2010sourced long\u2010chain omega\u20103 fatty acids was not appreciably associated with fecundability in either cohort ( 65200 vs. <50 g/week total seafood: FR = 0.94, 95% CI: 0.79\u20131.10 in Snart Foraeldre; FR = 1.00, 95% CI: 0.90\u20131.13 in PRESTO; marine fatty acids: 6590th vs. <25th percentile: FR = 1.00, 95% CI: 0.85\u20131.18 in Snart Foraeldre; FR = 0.97, 95% CI: 0.86\u20131.09 in PRESTO). In PRESTO, where we collected additional data on seafood preparation, we observed an inverse association between fecundability and fried shellfish ( 6510 g/week vs. none: FR = 0.77, 95% CI: 0.61\u20130.98), but not unfried shellfish ( 6520 g/week vs. none: FR = 0.98, 95% CI: 0.89\u20131.07); in Snart Foraeldre, there was no association with total shellfish intake. Conclusions: We found little association between seafood intake and fecundability overall, but greater intake of fried shellfish was associated with reduced fecundability among North American participants
UNAFLOW project: UNsteady Aerodynamics of FLOating Wind turbines
UNAFLOW (UNsteady Aerodynamics for Floating Wind) is a joint EU-IRPWIND founded experiment on wind turbine rotor unsteady aerodynamics. It brings together four different academic contributors: Energy research Centre of the Netherlands (ECN), DTU Wind Energy, University of Stuttgart (USTUTT) and Politecnico di Milano (PoliMi) sharing knowledge both in numerical modelling and in experimental tests design, allowing direct numerical and experimental comparison. The experimental tests carried out for UNAFLOW are of the same type of the ones carried out during the ongoing EU H2020 project LIFES50+ [1], regarding both the unsteady behaviour of the 2d blade section and the entire turbine rotor, although with improved setup and wider test matrix. The project partners are already currently jointly collaborating in the AVATAR project [2], developing and validating numerical models of different accuracy level. The numerical models used in the UNALFOW project range from engineering tool (eg. BEM) to high fidelity CFD methods. Numerical simulations are used both in the design of experiment phase and in the results analysis allowing for an in depth understanding of the experimental findings through advanced modelling approach. The UNAFLOW project, together with a new understanding of the unsteady behaviour of the turbine rotor aerodynamics, will provide also an open database to be shared among the scientific community for future analysis and new models validation
The role of E1-E2 interplay in multiphonon Coulomb excitation
In this work we study the problem of a charged particle, bound in a
harmonic-oscillator potential, being excited by the Coulomb field from a fast
charged projectile. Based on a classical solution to the problem and using the
squeezed-state formalism we are able to treat exactly both dipole and
quadrupole Coulomb field components. Addressing various transition amplitudes
and processes of multiphonon excitation we study different aspects resulting
from the interplay between E1 and E2 fields, ranging from classical dynamic
polarization effects to questions of quantum interference. We compare exact
calculations with approximate methods. Results of this work and the formalism
we present can be useful in studies of nuclear reaction physics and in atomic
stopping theory.Comment: 10 pages, 6 figure
Microtearing Instability In The ITER Pedestal
Unstable microtearing modes are discovered by the GS2 gyrokinetic siimulation code, in the pedestal region of a simulated ITER H-mode plasma with approximately 400 WM DT fusion power. Existing nonlinear theory indicates that these instabilities should produce stochastic magnetic fields and broaden the pedestal. The resulted electron thermal conductivity is estimated and the implications of these findings are discussed
Record deflection efficiencies measured for high energy protons in a bent germanium crystal
New experimental results on the deflection of high energy protons in a bent germanium crystal are presented. At 450 GeV/c, the 50 mm long crystal gave record deflection efficiencies up to 60% for small angles (1 mrad), while at angles as large as 12 mrad, the efficiency is about 25 times larger than for a silicon crystal of the same size. The experimental results are in good agreement with a model for channeling and deflection developed by Ellison and give - together with a similar comparison for a 200 GeV/c beam - confidence in extrapolations to higher energies (e.g. to LHC), other crystal materials or different deflection angles
Modélisation de la performance hydraulique des toitures végétalisées, sur le long terme et pour des événements particuliers
Towards integration of research and monitoring at forest ecosystems in Europe
Aim of study: The main aim of the work was to summarize availability, quality and comparability of on-going European Research and Monitoring Networks (ERMN), based on the results of a COST FP0903 Action questionnaire carried out in September 2010 and May 2012. Area of study: The COST Action FP0903 involves 29 European countries and 4 non-COST institutions from USA, Morocco and Tunisia. In this study, the total of 22 replies to the questionnaire from 18 countries were included. Materials and methods: Based on the feedback from the Action FP0903 countries, the most popular European Networks were identified. Thereafter, the access to the network database, available quality assurance/quality control procedures and publication were described. Finally, the so-called âSupersitesâ concept, defined as a âhighly instrumented research infrastructure, for both research and monitoring of soil-plant-atmosphere interactionsâ was discussed. Main results: The result of the survey indicate that the vast majority of the Action FP0903 countries participate in the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forest (ICP Forest). The multi-disciplinary International Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems (ICPIM) is the second most widespread forest programme. Research highlights: To fully understand biochemical cycles in forest ecosystems, long-term monitoring is needed. Hence, a network of âSupersitesâ, is proposed. The application of the above infrastructure can be an effective way to attain a better integration of research and monitoring networks at forest sites in Europ
What can food service operators do to remedy undernutrition in hospitals? â a European perspective from an ad hoc group on Nutrition Programmes in Hospitals
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