Hardening self-compacing mortar expsoed to gamma radiation

For the disposal of high level radioactive waste, cementitious barriers are considered worldwide and for various purposes. The Belgian supercontainer concept, for example, considers the use of cylindrical concrete containers: the radwaste is emplaced inside a hardened self-compacting concrete buffer, and for closure of the supercontainer the remaining gap is filled by casting a selfcompacting mortar. As a consequence, this cementitious layer is exposed to the radioactive waste and gamma radiation during hardening. In this research study, small self-compacting mortar samples are irradiated by gamma rays during hardening, and exposed to different doses (Gy) and different dose rates (Gy/h) at different hardening times at first exposure to investigate the cement-waste interactions that might occur during hardening of the cementitious barrier. The effect on the strength and the microstructure is investigated, by means of compressive strength tests, scanning electron microscopy, and nitrogen adsorption tests. It was found that the observed strength loss due to gamma irradiation increases with an increasing total received dose. Furthermore, the age at which irradiation starts, plays a role in the effect of the gamma irradiation. A link between the strength of the mortar samples and its porosity is found by means of the nitrogen adsorption tests. A higher received dose increases the porosity which leads to a decrease in compressive strength. BET-analysis shows that the specific surface of the pores also increase due to gamma irradiation. Finally, SEM-analysis revealed that gamma irradiation during hardening of cementitious samples affects the microstructure

Accurate Reaction-Diffusion Operator Splitting on Tetrahedral Meshes for Parallel Stochastic Molecular Simulations

Spatial stochastic molecular simulations in biology are limited by the intense computation required to track molecules in space either in a discrete time or discrete space framework, meaning that the serial limit has already been reached in sub-cellular models. This calls for parallel simulations that can take advantage of the power of modern supercomputers; however exact methods are known to be inherently serial. We introduce an operator splitting implementation for irregular grids with a novel method to improve accuracy, and demonstrate potential for scalable parallel simulations in an initial MPI version. We foresee that this groundwork will enable larger scale, whole-cell stochastic simulations in the near future.Comment: 33 pages, 10 figure

Regular Patterns in Cerebellar Purkinje Cell Simple Spike Trains

Background. Cerebellar Purkinje cells (PC) in vivo are commonly reported to generate irregular spike trains, documented by high coefficients of variation of interspike-intervals (ISI). In strong co

Irregular screening participation increases advanced stage breast cancer at diagnosis:A population-based study

Objective: To evaluate the effect of irregular screening behaviour on the risk of advanced stage breast cancer at diagnosis in Flanders. Methods: All women aged 50–69 who were invited to the organized breast cancer screening and diagnosed with breast cancer before age 72 from 2001 to 2018 were included. All prevalent screen and interval cancers within 2 years of a prevalent screen were excluded. Screening behaviour was categorized based on the number of invitations and performed screenings. Four groups were defined: regular, irregular, only-once, and never attenders. Advanced stage cancer was defined as a stage III + breast cancer. The association between screening regularity and breast cancer stage at diagnosis was evaluated in multivariable logistic regression models, taking age of diagnosis and socio-economic status into account. Results: In total 13.5% of the 38,005 breast cancer cases were diagnosed at the advanced stage. Compared to the regular attenders, the risk of advanced stage breast cancer for the irregular attenders, women who participated only-once, and never attenders was significantly higher with ORadjusted:1.17 (95%CI:1.06–1.29) and ORadjusted:2.18 (95%CI:1.94–2.45), and ORadjusted:5.95 (95%CI:5.33–6.65), respectively. Conclusions: In our study, never attenders were nearly six times more likely to be diagnosed with advanced stage breast cancer than regular attenders, which was much higher than the estimates published thus far. An explanation for this is that the ever screened women is a heterogeneous group regarding the participation profiles which also includes irregular and only-once attenders. The benefit of regular screening should be informed to all women invited for screening

Nautical bottom sediment research: Sub report 11. Cohesive sediments dimensional analysis

The dimensional analysis technique was applied in order to determine possible relationships between the measured parameters in the STT and to identify possible inconsistencies in the measurements.The present dimensional analysis focuses only in the sedimentation and consolidation processes.Relationships between parameters could be used to identify inconsistencies for measured pore pressure, effective stresses and density values. Recommendations are suggested for sampling points and measuring methods

Spatiotemporal network coding of physiological mossy fiber inputs by the cerebellar granular layer

The granular layer, which mainly consists of granule and Golgi cells, is the first stage of the cerebellar cortex and processes spatiotemporal information transmitted by mossy fiber inputs with a wide variety of firing patterns. To study its dynamics at multiple time scales in response to inputs approximating real spatiotemporal patterns, we constructed a large-scale 3D network model of the granular layer. Patterned mossy fiber activity induces rhythmic Golgi cell activity that is synchronized by shared parallel fiber input and by gap junctions. This leads to long distance synchrony of Golgi cells along the transverse axis, powerfully regulating granule cell firing by imposing inhibition during a specific time window. The essential network mechanisms, including tunable Golgi cell oscillations, on-beam inhibition and NMDA receptors causing first winner keeps winning of granule cells, illustrate how fundamental properties of the granule layer operate in tandem to produce (1) well timed and spatially bound output, (2) a wide dynamic range of granule cell firing and (3) transient and coherent gating oscillations. These results substantially enrich our understanding of granule cell layer processing, which seems to promote spatial group selection of granule cell activity as a function of timing of mossy fiber input

Bioeconomy Transitions through the Lens of Coupled Social-Ecological Systems: A Framework for Place-Based Responsibility in the Global Resource System

Bioeconomy strategies in high income societies focus at replacing finite, fossil resources by renewable, biological resources to reconcile macro-economic concerns with climate constraints. However, the current bioeconomy is associated with critical levels of environmental degradation. As a potential increase in biological resource use may further threaten the capacity of ecosystems to fulfil human needs, it remains unclear whether bioeconomy transitions in high income countries are sustainable. In order to fill a gap in bioeconomy sustainability assessments, we apply an ontological lens of coupled social-ecological systems to explore critical mechanisms in relation to bioeconomy activities in the global resource system. This contributes to a social-ecological systems (SES)-based understanding of sustainability from a high income country perspective: the capacity of humans to satisfy their needs with strategies that reduce current levels of pressures and impacts on ecosystems. Building on this notion of agency, we develop a framework prototype that captures the systemic relation between individual human needs and collective social outcomes on the one hand (micro-level) and social-ecological impacts in the global resource system on the other hand (macro-level). The BIO-SES framework emphasizes the role of responsible consumption (for physical health), responsible production (to reduce stressors on the environment), and the role of autonomy and self-organisation (to protect the reproduction capacity of social-ecological systems). In particular, the BIO-SES framework can support (1) individual and collective agency in high income country contexts to reduce global resource use and related ecosystem impacts with a bioeconomy strategy, (2) aligning social outcomes, monitoring efforts and governance structures with place-based efforts to achieve the SDGs, as well as (3), advancing the evidence base and social-ecological theory on responsible bioeconomy transitions in the limited biosphere