Food-borne diseases associated with frozen berries consumption: A historical perspective, European Union, 1983 to 2013

Epidemiological investigations of outbreaks of hepatitis A virus (HAV) and norovirus (NoV) infections in the European Union/European Economic Area (EU/EEA) in the last five years have highlighted frozen berries as a vehicle of infection. Given the increasing berry consumption in the EU over the last decades, we undertook a review of the existing evidence to assess the potential scale of threat associated with this product. We searched the literature and four restricted-access online platforms for outbreak/contamination events associated with consumption of frozen berries. We performed an evaluation of the sources to identify areas for improvement. The review revealed 32 independent events (i.e. outbreak, food contamination) in the period 1983–2013, of which 26 were reported after 2004. The identified pathogens were NoV, HAV and Shigella sonnei. NoV was the most common and implicated in 27 events with over 15,000 cases reported. A capture–recapture analysis was performed including three overlapping sources for the period 2005–2013. The study estimated that the event-ascertainment was 62%. Consumption of frozen berries is associated with increasing reports of NoV and HAV outbreaks and contamination events, particularly after 2003. A review of the risks associated with this product is required to inform future prevention strategies. Better integration of the available communication platforms and databases should be sought at EU/EEA level to improve monitoring, prevention and control of food-bornerelated events

Strain gradient plasticity analysis of the strength and ductility of thin metallic films using an enriched interface model

The mechanical response of thin metallic films is simulated using a two-dimensional strain gradient plasticity finite-element model involving grain boundaries in order to investigate the effect of the thickness, grain shape and surface constraint on the strength, ductility and back-stress. The grain boundaries and surface layers are modeled as initially impenetrable to dislocations while allowing for relaxation at a critical stress level. The model captures the variation of the strength with grain size, film thickness, and with the presence or not of constraining surface layers, in agreement with experimental results on Al and Cu films. A decrease in the uniform elongation is predicted with decreasing film thickness due to a loss of strain-hardening capacity and the possible presence of imperfections. These two effects dominate over the stabilizing contribution of the plastic strain gradients. Accounting for the relaxation of the interface constraint affects the magnitude of the back-stress as well as the drop in ductility.Institute of Mechanics, Materials and Civil Engineering, Universite´ catholique de Louvain, 1348 Louvain-la-Neuve, Belgium b Universite´ Libre de Bruxelles, Building, Architecture & Town Planning Dept. (BATir) CP 194/02, Avenue F.D. Roosevelt 50, 1050 Bruxelles, Belgiu

Formation and structure of the turbidity maximum in the macrotidal Charente estuary (France): Influence of fluvial and tidal forcing

International audienceUnderstanding estuarine sediment dynamics, and particularly turbidity maximum dynamics, is crucial for the management of these coastal systems. Various processes impact the formation, movement and structure of the turbidity maximum. Several studies have shown that tidal asymmetry and density gradients are responsible for the presence of this suspended sedimentary mass. The Charente estuary is a highly turbid system (with suspended sediment concentrations mostly in excess of 5 g/L) that remains poorly understood, despite its strong impact on local activities. In this study, a three-dimensional hydrosedimentary model is developed to represent the sediment dynamics of this estuary. Model validation demonstrates good accuracy, especially on reproducing semi-diurnal and spring-neap variability. Several simulations are performed to evaluate the influence of tides and river discharge on the turbidity maximum. Mean and maximum suspended sediment concentrations (S S C) and sediment stratification, are calculated. S S C transects are also used to visualise the suspended sediment distribution along the estuary. The turbidity maximum generally oscillates between the river mouth and the Rochefort area (20-30 km upstream). The model shows strong variations at different time scales, and demonstrates that S S C is mainly driven by deposi-tion/resuspension processes. Spring-neap comparisons show that the turbidity maximum is not well-defined during neap tides, for low and mean runoff conditions. Simulations of spring tides and/or high runoff conditions all result in a compact suspended sedimentary mass. Performing simulations without taking density gradients into account demonstrates that tidal asymmetry is the main mechanism leading to the formation of the turbidity maximum. However, density gradients contribute to maintaining the stability of the turbidity maximum. Vertical stratification traps sediments at the bottom. Longitudinal stratification ensures a sharper edge at the downstream limit of the suspended sedimentary mass, preventing a massive export of sediments

Fortnightly tidal asymmetry inversions and perspectives on sediment dynamics in a macrotidal estuary (Charente, France)

Tidal asymmetry is a phenomenon that characterises estuarine hydrodynamics and has a strong impact on sediment dynamics. Extensive research has been dedicated to studying tidal dynamics in semidiurnal macrotidal estuaries, highlighting several general principles. The ratio of flood to ebb peak velocities and differences in ebb and flood durations are often used to characterise the asymmetry encountered in estuaries. In the Charente estuary (French Atlantic coast), water surface elevation data obtained using an ADCP (Acoustic Doppler Current Profiler) and a tide gauge show that the duration asymmetry undergoes inversions during the spring-neap tidal cycle. A two-dimensional hydrodynamics model is used to investigate the connection between spring-neap inversions of the tidal asymmetry and the harmonic composition of the tide. Different constituents (M2, S2, M4 and MS4) are considered at the open boundary. The results show that M4 and MS4 play a key role in the occurrence of these inversions. The influence of the morphology is also discussed and modifications of the bathymetry are performed to evaluate its impact. In the Charente estuary, the existence of both externally and internally generated overtides thus results in a spatially and fortnightly variable tidal asymmetry. The modelled barotropic tidal currents are used to estimate the possible impact on sediment dynamics. The results suggest that asymmetry inversions tend to create sediment accumulation in an intermediate zone between the river mouth and Rochefort, located approximately 20 km upstream

New MEMS-based nanomechanical testing laboratory - application to aluminium, titanium, polysilicon and silicon nitride thin films.

International audienc

Creep behavior of submicron copper films under irradiation

International audienc

#Swineflu: Twitter predicts swine flu outbreak in 2009

Early warning systems for the identification and tracking of infections disease outbreaks have become an important tool in the field of epidemiology. While government lead initiatives to increase the sharing of surveillance data have improved early detection and control, along with advanced web monitoring and analytics services, the recent swine flu outbreak of 2009 demonstrated the important role social media has and the wealth of data it exposes. In this paper, we present an investigation into Twitter, using around 3 Million tweets gathered between May and December 2009, as a possible source of surveillance data and its feasibility to serve as an early warning system. By performing simple filtering and normalization, we demonstrate that Twitter can serve as a self-reporting tool, and hence, provide indications of increased infection spreading. Our initial findings indicate that Twitter can detect such events up to one week before conventional GP reported surveillance data

Microfabrication-based nanomechanical laboratory for testing the ductility of submicron aluminium films

International audienceThe measurement of the mechanical properties of materials with submicron dimensions is extremely challenging, from the preparation and manipulation of specimens, to the application of small loads and extraction of accurate displacements. Here, we present results obtained on 250 nm-thick aluminium films using a novel versatile concept of micro and nano-machines allowing multiple loading configurations and geometries. The focus is put on the fracture strain defined either as the strain at necking under uniaxial tension or the local strain at cracking initiation. The ductility of free-standing thin metallic films is one of the mechanical properties which is rarely measured and discussed in the literature. The necking and fracture strains are found equal to 0.08 and 0.3, respectively. Depending on the application, such as the development of flexible electronics or the reliability of interconnects, and on the loading conditions, one or both of these ductility indices can be key in the definition of fail-safe designs. This study enlightens also the interest and potential of the new nanomechanical testing concept