HAL-Université de Bretagne Occidentale
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Exploring seaweed potential as a sustainable food source
No full textInternational audienceGeneral presentation: In a context of food sustainability while ensuring food safety and security, the search for innovative foods is crucial. Despite major efforts to guarantee access to food supplies for as many people as possible, global hunger is still increasing. At the same time, dietary plan of developing countries particularly in Asia, are evolving towards the Western model (more lipids and animal proteins). But this disbalanced diet is known to lead to overweight and obesity, that are associated with increased risk incidence of chronic diseases such as cardiovascular diseases, type-2 diabetes or cancer. In addition, the gradual generalization of this tendency to consume animal proteins to the entire world population raises the environmental issues of the sustainability of food systems, whether production systems or processing industries. In this context, seaweeds are of interest because of the nutritional potential of this naturally available marine resource. Seaweeds are generally regarded as a viable and renewable protein source as their essential amino acid composition meets FAO requirements and they are often comparable to other protein sources, such as soybean or egg. In addition, they present positive characteristics of production environmental and societal impact (reduction of soil degradation and use of arable land, decrease of freshwater consumption for example) and benefit from the EU’s Farm to Fork strategy indeed specifically mentions ‘well-targeted support for the algae industry, as algae should become an important source of alternative protein for a sustainable food system and global food security. However, despite a promising potential as new food in Western, only 1% of produced seaweeds are used as food like vegetable, available mainly from producers with short marketing circuit, and with organic labels most of the time. Objectives: This workshop aims to present recent advances in research on the aquaculture, processing, and preservation of edible seaweeds, with a focus on species with high nutritional and commercial potential. It will facilitate international and cross-sector collaboration and is expected to drive forward the edible seaweed sector in France and internationally by promoting an integrated approach that combines innovation, sustainability, and product accessibility. The workshop will highlight successful case studies in the development of seaweed-based products and demonstrate their integration into contemporary cuisine, particularly in response to the growth of plant-based diets.Background: Seaweeds especially Ulva, Palmaria or Gracilaria genus have gained interest as a source of protein, due to the high production potential and high proportion of essential amino acids. This workshop will give an overview of seaweeds protein, including extraction, evaluation of protein quality in terms of nutritional value, sensory properties, and also consumer’s and health professionals’ perceptions and appropriability
Cohomologie bigraduée arithmétique d'espaces réels clos
No full textThe starting point of this thesis is the bigraded (analytic) cohomology of real algebraic varieties developed by Johannes Huisman and Dewi Gleuher. Using the study of uniquely divisible abelian groups as a pretext, we first present an arithmetic substitute for the complex analytic exponential based on its nice behavior with respect to n -th roots, or, in additive notation, its relationship with divisibility properties. The primary goal is to free the construction of analytic cohomology from any topological constraint on the objects considered. We then produce an arithmetic variant of this bigraded cohomology by extending the definition and properties of the arithmetic exponential to the framework of (Grothendieck) abelian categories and introducing a modified version of the notion of the profinite completion of a group. Next, we address the question, both in the analytic and arithmetic cases, of adapting this cohomological theory to algebraic varieties over any real closed field, relying on semi-algebraic methods: namely, the theory of (locally) semialgebraic spaces by H. Delfs and M. Knebusch. This leads us to ultimately prove a comparisontheorem between the analytic and arithmetic cohomologies for cellular complexes with finite skeletons.Le point de départ de cette thèse est la cohomologie bigraduée (analytique) des variétés algébriques réelles développée par Johannes Huisman et Dewi Gleuher. En prenant pour prétexte l’étude des groupes abéliens uniquement divisibles, nous présentons d’abord un substitut arithmétique à l’exponentielle analytique complexe basé sur le comportement agréable de cette dernière vis-à-vis des racines n-ièmes ou, en notation additive, de sa relation avec les propriétés de divisibilité. L’ambition première étant de s’affranchir de toute contrainte d’ordre topologique sur les objets considérés dans la construction de la cohomologie analytique, nous produisons dans un second temps une variante arithmétique de cette cohomologie bigraduée en étendant la définition et les propriétés de l’exponentielle arithmétique au cadre des catégories abéliennes (de Grothendieck) et en introduisant une version modifiée de la notion de complétion profinie d’un groupe. Nous nous occupons ensuite de répondre à la question, dans le cas analytique comme arithmétique, de l’adaptation de cette théorie cohomologique à des variétés algébriques sur un corps réel clos quelconque en s’appuyant sur des méthodes semialgébriques : à savoir, la théorie des espaces (localement) semi-algébriques de H. Delfs et M. Knebusch. Ceci nous amène finalement à démontrer un théorème de comparaison entre les cohomologies analytique et arithmétique pour les complexes cellulaires à squelettes finis
Rethinking datafied movements: A critical comparison of direct action and lobbying as data activism in an urban context
No full textInternational audienceIn this paper, we build on the concept of datafied movements (Milan & Beraldo, 2024) by examining the different forms of urban data activism evident in two distinct strategies: direct action to counter evictions and lobbying the media and policy makers on planning. Through an in-depth analysis of two case studies that employed ethnographic fieldwork, interviews, and workshops using arts-based methods, the strategies mobilised by two citizens’ groups in Dublin are examined. Direct action collects data through and in aid of the work of building community and institutional capacity, visibility, legitimacy, and resisting evictions on the ground. Organisations using lobbying as a form of activism adopt a more indirect but equally impactful approach, using the means of contestation put in place by the state (e.g. consultation). In both cases, data practices and the use of data forms part of the strategy for a bottom-up, evidence-based approach, employing decentralised networks to disseminate tactics and influence discourse. On the other hand, the work carried out by these organisations shows an uneven and particularly inconsistent use of data. We suggest that while data work has become a necessity for social movements in a datafied society, what form this data work takes depend on the ideals and theories of social change those organisations undertaking data work hold. These data values are under-emphasised in the datafied movement concept. The comparative approach taken provides clear evidence of the need for a diverse and complementary set of networks and data activisms to fight for the right to the city
Makarenko, l’écrivain, le combattant et le pédagogue : fiction(s) et pédagogie
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« Jeunes générations à l’ère du numérique : une lecture psychosociale » ?
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Technical Validation of a Spatial Tracking Configuration for Augmented and Co-Localized Medical Assistance Under Gravity Variations in Parabolic Flights
No full textInternational audienceAugmented reality is a promising technology for enhancing remote medical assistance. It assists users by directly projecting the relevant virtual assistance in the real world at the right moment and at the right location. This modality is called colocalization but has not been validated in parabolic flights. Our hypothesis was that this modality is technically feasible in weightlessness and is superior to a paper checklist in assisting a caregiver during a simulated medical emergency. Methods During parabolic flight campaigns, we conducted an abdominal pain simulation scenario and sought to compare procedural assistances. Participants performed a basic medical examination using either classic cognitive aids (such as a paper checklist) or an augmented-reality device projecting visual co-localized (situated or embedded) assistance. Results Gravity variations induced technical difficulties in the nominal functioning of augmented-reality headsets due to the native accelerometers in these devices. Clinical data were not interpretable due to small sample size secondary to the technical difficulties encountered. Finally, an efficient and stable spatial tracking configuration was found during the last flight, offering future research perspectives. Conclusions Our study validated the first achievement of a stable co-localized assistance under gravity variation. The augmented-reality headset required an external tracking system based on surrounding infrared cameras and an in-flight calibration to recreate the virtual environment (spatial mapping) independently of gravity conditions. Further studies are needed to clinically validate the potential benefits of co-localized augmented reality for space medicine
Figurations of the Scottish coastline in pro- and anti-wind energy art and discourse
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Rethinking Dosimetry: A European Perspective
No full textInternational audienceRadiopharmaceutical therapy (RPT) is entering a new era of personalization, driven by advances in molecular imaging, radiopharmaceutical development, and a growing body of clinical evidence linking absorbed dose to treatment outcomes. Although external-beam radiotherapy has long integrated dosimetry into standard practice, RPT historically relied on fixed radiopharmaceutical activities and absorbed dose-effect relationships adapted from external-beam radiotherapy, often without accounting for the unique pharmacokinetics, absorbed dose rate dynamics, and biologic responses of systemically administered radiopharmaceuticals. As RPT expands into earlier disease stages, at which patients have longer life expectancies and better performance status, the role of dosimetry in optimizing treatment is becoming increasingly evident. However, despite growing recognition of its benefits, the implementation of dosimetry in clinical practice remains limited, partly because of a self-reinforcing cycle in which the lack of routine dosimetry limits clinical evidence, which in turn hinders its broader adoption. Breaking this cycle is essential to advancing RPT and ensuring that evaluation of dosimetry is based on clinical merit rather than logistic constraints. This article examines the current landscape of RPT dosimetry, highlighting key challenges and opportunities from a European perspective and aiming to foster a more factual and constructive discussion on the topic. We discuss the fundamental differences between dosimetry-driven treatment planning and posttherapy absorbed dose verification, emphasizing the latter as a practical entry point for clinical adoption. We underscore the need for harmonized standards, improved imaging resolution, and tailored absorbed dose-effect relationships that reflect the heterogeneity of RPT delivery and the complexity of tumor and organ responses. The paper also addresses regulatory, infrastructural, and resource barriers to RPT dosimetry implementation and highlights ongoing European initiatives to strengthen frameworks, enhance stakeholder collaboration, and integrate absorbed dose biomarkers into authorization processes and clinical decision-making. By rethinking dosimetry and promoting standardized, evidence-based approaches, the field can advance beyond fixed-activity protocols toward truly individualized RPT. However, achieving clinically feasible integration of dosimetry into routine practice requires structured efforts to generate high-quality clinical evidence and improve accessibility. Ultimately, reliable, patient-centered dosimetry has the potential to enhance therapeutic efficacy, manage toxicity more effectively, and support the long-term evolution of RPT as a cornerstone of precision oncology
Experimental study and modelling of shock-induced compaction of autoclaved aerated concrete through MHz X-ray radioscopy
No full textInternational audienceExtreme scenarios related to sudden increase of stress states, such as mechanical impacts or collisions, can lead to severe physical damage on structures. However, through their compaction phase, porous materials absorb a part of mechanical energy and efficiently mitigate the shock wave induced damage. Autoclaved Aerated Concrete (AAC) is one type of cellular materials which exhibits such capability and also being non-flammable, which is of interest for most structures that must resist both impacts and fire. With good insulation properties and its low density, AAC is therefore a material of choice in protective design against shock loading. It is however difficult to study in real time, especially because of the cloud of dust produced during compaction. In the present study, two AAC of respective densities of 550 kg/m3 and 115 kg/m3 are considered. Plate impact tests were performed at the European Synchrotron Radiation Facility (ESRF) and the compaction process was observed in-situ by ultra-fast X-ray phase-contrast radioscopy for impact velocities ranging from 250 to 400 m/s. Through the records analysis, a compaction front is identified..The tracking of the compaction front and the initial velocity of the projectile provide a portion of the AAC compacted state. In line with the findings, an extended analysis extracting the mean pore size and the evolution of the densities and speed of sounds is conducted by the use of laser induced shock waves on samples pre-compacted. An analytical model is proposed to reproduce the compaction front dynamics, considering equivalent mass-spring system
