101 research outputs found
Heat risk assessment for the Brussels capital region under different urban planning and greenhouse gas emission scenarios
Urban residents are exposed to higher levels of heat stress in comparison to the rural population. As this phenomenon could be enhanced by both global greenhouse gas emissions (GHG) and urban expansion, urban planners and policymakers should integrate both in their assessment. One way to consider these two concepts is by using urban climate models at a high resolution. In this study, the influence of urban expansion and GHG emission scenarios is evaluated at 100 m spatial resolution for the city of Brussels (Belgium) in the near (2031-2050) and far (2081-2100) future. Two possible urban planning scenarios (translated into local climate zones, LCZs) in combination with two representative concentration pathways (RCPs 4.5 and 8.5) have been implemented in the urban climate model UrbClim. The projections show that the influence of GHG emissions trumps urban planning measures in each period. In the near future, no large differences are seen between the RCP scenarios; in the far future, both heat stress and risk values are twice as large for RCP 8.5 compared to RCP 4.5. Depending on the GHG scenario and the LCZ type, heat stress is projected to increase by a factor of 10 by 2090 compared to the present-day climate and urban planning conditions. The imprint of vulnerability and exposure is clearly visible in the heat risk assessment, leading to very high levels of heat risk, most notably for the North Western part of the Brussels Capital Region. The results demonstrate the need for mitigation and adaptation plans at different policy levels that strive for lower GHG emissions and the development of sustainable urban areas safeguarding livability in cities
Developmental change in motor competence : a latent growth curve analysis
Background: The development of childhood motor competence demonstrates a high degree of inter-individual variation. Some children's competence levels increase whilst others' competence levels remain unchanged or even decrease over time. However, few studies have examined this developmental change in motor competence across childhood and little is known on influencing factors.
Aim: Using latent growth curve modeling (LGCM), the present longitudinal study aimed to investigate children's change in motor competence across a 2-year timespan and to examine the potential influence of baseline weight status and physical fitness on their trajectory of change in motor competence.
Methods: 558 children (52.5% boys) aged between 6 and 9 years participated in this study. Baseline measurements included weight status, motor competence (i.e., Korperkoordinationstest fur Kinder; KTK) and physical fitness (i.e., sit and reach, standing long jump and the 20 m shuttle run test). Motor competence assessment took place three times across a 2-year timespan. LGCM was conducted to examine change in motor competence over time.
Results: The analyses showed a positive linear change in motor competence across 2 years (beta = 28.48, p < 0.001) with significant variability in children's individual trajectories (p < 0.001). Girls made less progress than boys (beta = -2.12, p = 0.01). Children who were older at baseline demonstrated less change in motor competence (beta = -0.33, p < 0.001). Weight status at baseline was negatively associated with change in motor competence over time (beta = -1.418, p = 0.002). None of the physical fitness components, measured at baseline, were significantly associated with change in motor competence over time.
Conclusion and Implications: This longitudinal study reveals that weight status significantly influences children's motor competence trajectories whilst physical fitness demonstrated no significant influence on motor competence trajectories. Future studies should further explore children's differential trajectories over time and potential factors influencing that change
The use of equine chondrogenic‐induced mesenchymal stem cells as a treatment for osteoarthritis : a randomised, double‐blinded, placebo‐controlled proof‐of‐concept study
Background: There is a need to improve therapies for osteoarthritis in horses. Objectives To assess the efficacy of equine allogeneic chondrogenic-induced mesenchymal stem cells combined with equine allogeneic plasma as a novel therapy for osteoarthritis in horses.
Study design: Randomised, double-blinded, placebo-controlled experiment.
Methods: In 12 healthy horses, osteoarthritis was induced in the metacarpophalangeal joint using an osteochondral fragment-groove model. Five weeks after surgery, horses were randomly assigned to either an intra-articular injection with chondrogenic-induced mesenchymal stem cells + equine allogeneic plasma (= intervention) or with 0.9% saline solution (= control). From surgery until the study end, horses underwent a weekly joint and lameness assessment. Synovial fluid was collected for cytology and biomarker analysis before surgery and at Weeks 5, 5 + 1d, 7, 9 and 11. At Week 11, horses were subjected to euthanasia, and the metacarpophalangeal joints were evaluated macroscopically and histologically.
Results: No serious adverse events or suspected adverse drug reactions occurred during the study. A significant improvement in visual and objective lameness was seen with the intervention compared with the control. Synovial fluid displayed a significantly higher viscosity and a significantly lower glycosaminoglycan concentration in the intervention group. Other biomarkers or cytology parameters were not significantly different between the treatment groups. Significantly less wear lines and synovial hyperaemia were present in the intervention group. The amount of cartilage oligomeric matrix protein, collagen type II and glycosaminoglycans were significantly higher in the articular cartilage of the intervention group.
Main limitations: This study assessed the short-term effect of the intervention on a limited number of horses, using an osteoarthritis model. This study also included multiple statistical tests, increasing the risk of type 1 error.
Conclusions: Equine allogeneic chondrogenic-induced mesenchymal stem cells combined with equine allogeneic plasma may be a promising treatment for osteoarthritis in horses
Cognitive function, motor and balance performances in vestibular impaired school aged children : 'the balanced growth protocol'
Optimising finishing pig delivery weight : participatory decision problem analysis
The seemingly straightforward question of optimal pig delivery weight is more complex than meets the eye. Despite abundant research insights, the industry continues to request additional applied scientific decision support on the delivery weight problem. The current objective is to investigate whether and how the complex decision of delivery weight can be reshaped (reframed) into a more tangible and comprehensible system of factors that matter for making the right decision. We used a participatory decision problem analysis, which resulted in modelling blueprints that incorporate factors prioritised by stakeholders for determining optimal delivery weights. How to efficiently organise such a 'problem reframing process' is case-specific: it depends on the objective, the initial problem understanding by the stakeholders, and their learning potential. Efficient co-learning is a prerequisite for successful participatory problem analysis. Our study reveals that the first step in such a process of 'problem reframing' should therefore be to answer the question of how to effectively organise co-learning among stakeholders and researchers, instead of starting with a correct and detailed representation of the problem. Useful guidelines for participatory problem reframing processes are (1) providing sufficient participatory learning steps, (2) having few and clearly defined objectives per learning step, (3) providing adapted learning tools per step, (4) establishing a common language and (5) deliberately choosing stakeholders based on prior knowledge of the problem or its context, potential motivation or incentives to be part of the participatory process step and potential role in up-scaling the co-learning process to a larger group of beneficiaries
3D simulations of AGB stellar winds -- II. Ray-tracer implementation and impact of radiation on the outflow morphology
Stars with an initial mass below ~ 8 Msun evolve through the asymptotic giant
branch (AGB) phase, during which they develop strong stellar winds. Recent
observations have revealed significant morphological complexities in their
outflows, most likely caused by a companion. We study the impact of the
radiation force on such companion-perturbed AGB outflows. We present the
implementation of a ray tracer for radiative transfer in smoothed particle
hydrodynamics (SPH) and compared four different descriptions of radiative
transfer: the free-wind, the geometrical, the Lucy, and the attenuation
approximation. For both low and high mass-loss rates, the velocity profile of
the outflow is modified when going from the free-wind to the geometrical
approximation, also resulting in a different morphology. In the case of a low
mass-loss rate, the effect of the Lucy and attenuation approximation is
negligible due to the low densities but morphological differences appear in the
high mass-loss rate regime. By comparing the radiative equilibrium temperature
and radiation force to full 3D radiative transfer, we show that the Lucy
approximation works best. Although, close to the companion, artificial heating
occurs and it fails to simulate the shadow cast by the companion. The
attenuation approximation produces a lower equilibrium temperature and weaker
radiation force, but it produces the shadow cast by the companion. From the
predictions of the 3D radiative transfer, we also conclude that a radially
directed radiation force is a reasonable assumption. The radiation force thus
plays a critical role in dust-driven AGB winds, impacting the velocity profile
and morphological structures. For low mass-loss rates, the geometrical
approximation suffices, while high mass-loss rates require a more rigorous
method, where the Lucy approximation provides the most accurate results
although not accounting for all effects
3D Line Radiative Transfer & Synthetic Observations with Magritte
Electromagnetic radiation is a key component in many astrophysical simulations. Not only does
it dictate what we can or cannot observe, it can provide radiation pressure, efficient heating and
cooling mechanisms, and opens up a range of new chemical pathways due to photo-reactions.
Magritte is a software library that can be used as a general-purpose radiative transfer solver,
but was particularly designed for line radiative transfer in complex 3D morphologies, such
as, for instance, encountered in the stellar winds around evolved stars (see Decin, 2020). It
is mainly written in C++ and can either be used as a Python package or as a C++ library.
To compute the radiation field, a deterministic ray-tracer and a formal solver are employed,
i.e., rays are traced through the model and the radiative transfer equation is solved along
those rays (De Ceuster et al., 2019). This is in contrast to most radiative transfer solvers
which employ (probabilistic) Monte Carlo techniques (Noebauer & Sim, 2019). By virtue
of minimal assumptions about the underlying geometric structure of a model, Magritte can
handle structured and unstructured input meshes, as well as smoothed-particle hydrodynamics
(SPH) data. Furthermore, tools are provided to optimise different input meshes for radiative
transfer (De Ceuster et al., 2020)
The evaluation of equine allogeneic tenogenic primed mesenchymal stem cells in a surgically induced superficial digital flexor tendon lesion model
Background: Tendon injuries are very common in horses and jeopardize the athletic performance, and due to the high risk of reinjury may lead to early retirement. The use of mesenchymal stem cells for the treatment of equine tendon disease is widely investigated because of their regenerative potential. The objective of this study is to investigate the safety and efficacy of equine allogeneic tenogenic primed mesenchymal stem cells (tpMSCs) for the management of tendinitis in horses. Methods: A core lesion was surgically induced in the superficial digital flexor tendon of both forelimbs of eight horses. After 7 days, one forelimb was treated with tpMSCs, while the contralateral forelimb served as an intra-individual control and was treated with saline. A prescribed exercise program was started. All horses underwent a daily clinical evaluation throughout the entire study period of 112 days. Blood samples were taken at different time points for hematological and biochemical analysis. Tendon assessment, lameness examination, ultrasound assessment and ultrasound tissue characterization (UTC) were performed at regular time intervals. At the end of the study period, the superficial digital flexor tendons were evaluated macroscopically and histologically. Results: No suspected or serious adverse events occurred during the entire study period. There was no difference in local effects including heat and pain to pressure between a single intralesional injection of allogeneic tpMSCs and a single intralesional injection with saline. A transient moderate local swelling was noted in the tpMSC treated limbs, which dissipated by day 11. Starting at a different time point depending on the parameter, a significant improvement was observed in the tpMSC treated limbs compared to the placebo for echogenicity score, fiber alignment score, anterior-posterior thickness of the tendon and echo type by UTC assessment. Immunohistochemistry 112 days post-injection revealed that the amount of collagen type I and Von Willebrand factor were significantly higher in the tendon tissue of the tpMSC group, while the amount of collagen type III and smooth muscle actin was significantly lower. Conclusion: Equine allogeneic tenogenic primed mesenchymal stem cells were shown to be well-tolerated and may be effective for the management of tendon injuries
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