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2D Bijective rigid rotation: quantitative and qualitative study
No full textInternational audiencePreserving surfaces or volumes is crucial when applying rigid transformations of 2D/3D digital objects in medical images and computer vision. To achieve this goal, the digital geometry community has focused on characterizing bijective digitized rotations and reflections. However, the angular distribution of these bijective rigid transformations is far from being dense. Other bijective approximations of rigid transformations have been proposed, but the state-of-the-art methods lack the experimental evaluations necessary to include them in real-life applications. This paper presents several new methods to approximate digitized rotations with bijective transformations, including the composition of bijective digitized reflections, bijective rotation by circles and bijective rotation through optimal transport. These new methods and several classical ones are compared in terms of accuracy with respect to Euclidean rotations, as well as computational complexity and practical speed in real-time applications and continuity. Finally, we determine some topological stability results of bijective rigid rotations
Thresholds of functional trait diversity driven by land use intensification
No full textInternational audienceIt is unclear how much land use intensification ecosystems can withstand before undergoing abrupt changes in their structure and dynamics. Here we assess how the functional structure, diversity and temporal stability of 150 agricultural grasslands responded to large variations in land use intensification, namely, different intensities of fertilization, grazing and mowing. Using multi-site time series (2008–2020) of plant trait distributions, we identify two thresholds where the functional structure, diversity and stability of grasslands changed dramatically. The first threshold occurred between unfertilized and fertilized grasslands, with maximization of trait evenness indicating the persistence of plant species with diverse resource-use strategies in extensively managed grasslands. The second threshold occurred when fertilization exceeded 80 kg N ha−1 yr−1 or when grazing exceeded 500 livestock units days ha−1 yr−1, beyond which the most intensively managed grasslands were functionally poor, highly unstable and vulnerable to extreme weather events. These findings allow us to quantify the level of perturbation beyond which grasslands depart from a high biodiversity state and show that highly intensive management pushes the system to a more unstable state. The identified thresholds may provide targets for sustainable management and fertilization practices
Guidelines for the FAIRt publication of Terrestrial Laser Scanner Data in Geomorphic Research
No full textThe increasing dissemination of data from Terrestrial or Permanent Laser Scanning (TLS/PLS) topographic surveys in geomorphology requires the establishment of clear recommendations for their publication. The work presented here proposes a framework to ensure that published datasets comply with the FAIRt (Findable, Accessible, Interoperable, Reusable, trustworthy) principles, with a particular attention on the documentation of the processing steps. This facilitates the evaluation of the relevance of published point clouds and their reuse. Central to this proposal is a set of structured metadata that is essential to document acquisition conditions, methodological choices and processing parameters in order to understand how the published cloud was obtained and what it can be used for. The framework presented in this article is organised into three distinct parts: the essential perimeter of publication, without which the cloud cannot be exploited, pre-processing and processing. These recommendations are accompanied by concrete examples of datasets to illustrate their implementation. To ensure the long-term interoperability of distribution, it is recommended that the LAS format be used as the standard for TLS clouds, associated with a GeoJSON file of metadata. This approach constitutes a component of a long-term preservation process, which is based on the use of open sharing and storage platforms. This standard is therefore intended to be a support tool for researchers, structuring publication practices while remaining open to adapt to future technological and scientific developments. Designed for TLS acquisitions, it could be extended to photogrammetric point clouds if specific photogrammetric processing information is provided
Inventaire et typologie des marges proglaciaires désenglacées entre le Petit Age Glaciaire et l'actuel dans les Alpes Françaises
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Using Eye Tracking to Evaluate Cognitive and Visual Outcomes of Early Life Phenol Exposure
No full textInternational audienceIntroduction: Studies on behavioral effects of synthetic phenols have often relied on parent-reported questionnaires and primarily focused on prenatal exposure.Aims: We examined associations between prenatal and infancy phenol exposures and objective measures of child visual behavior and cognitive function at 2 years of age.Methods: At age 2, 151 children from the SEPAGES mother-child cohort completed eye-tracking tasks assessing four indicators: fixation duration (attentional control), novelty preference (visual recognition memory), time spent looking at eyes (social attention), and reaction time (processing speed).Phenol concentrations (two bisphenols, three parabens, benzophenone-3, triclosan) were measured in multiple urine samples collected from mothers (second and third trimesters; median: 42 samples per woman) and infants (2 and 12 months; median: 7 samples).Results: No associations were found with ∑parabens. However, individual parabens showed significant associations: ethylparaben at third trimester (T3) and 12 months (M12) was linked to shorter reaction time; at 2 months (M2), it was associated with reduced time spent looking at eyes. Propylparaben at T2 and T3 correlated with increased time spent looking at a novel face, especially in boys. Bisphenol S at T2 was associated with reduced reaction time; at M12, infants with detectable bisphenol S was linked to more time spent looking at eyes.Conclusion: Several associations observed indicate that increased phenol exposure sometimes correlated with improved eye-tracking scores. These findings align with prior literature on phenol exposure and ASD symptoms, which highlight variability by exposure window and phenol type.Given limited research and typically small sample sizes, further studies using objective markers and clinical assessments are necessary
Muscle regeneration is improved by hot water immersion but unchanged by cold following a simulated musculoskeletal injury in humans
No full textInternational audienceCryotherapy is a popular strategy for the treatment of skeletal muscle injuries. However, its effect on post-injury human muscle regeneration remains unclear. In contrast, promising results recently emerged using heat therapy to facilitate recovery from muscle injury. This study aimed to examine the effect of three different thermal treatments on muscle recovery and regeneration following a simulated injury in humans. Thirty-four participants underwent a muscle damage protocol induced by electrically stimulated eccentric contractions triggering regenerative processes following myofibre necrosis. Thereafter, participants were exposed to daily lower body water immersion for 10 days in cold (CWI, 15 min at 12 degrees C), thermoneutral (TWI, 30 min at 32 degrees C) or hot water immersion (HWI, 60 min at 42 degrees C). Muscle biopsies were sampled before and at +5 (D5) and +11 (D11) days post-damage. None of the water immersions differed in recovery of force-generating capacity (P = 0.108). HWI induced a lower perceived muscle pain than TWI (P = 0.035) and lower levels of circulating creatine kinase (P <= 0.012) and myoglobin (P < 0.001) than TWI and CWI. Contrary to our hypothesis, CWI did not improve perceived muscle pain or reduce circulating markers of muscle damage (P >= 0.207). Expression of heat shock proteins 27 and 70 was significantly increased in HWI (P < 0.038) at D11 and appeared blunted using CWI. Furthermore, nuclear factor-kappa B expression significantly increased in all conditions except HWI, while interleukin-10 was upregulated only in HWI at D11 (P = 0.014). In conclusion, our results support the use of HWI but not cold, to improve muscle regeneration following an injury
LEON-BLOOM project - Origin, spatial and temporal dynamics of cyanobacteria blooms in lake Léon, France
No full textInternational audienceLake Léon (Landes) has recently experienced important cyanobacteria blooms, leading to severe restrictions on recreational activities of this popular tourist waterbody of the Atlantic coast in France. To investigate the origins of these algal blooms, the dynamics of biological patterns, and to provide management strategies for mitigation, the "Léon-Bloom" research project established a collaboration between environmental watershed managers and research scientists. The project aims to identify the potential sources of algal growth and gain a better understanding of their spatial and temporal dynamics. The project is structured in several workpackages, each investigating a potential mechanism. (1) Firstly, nutrient fluxes from the watershed are analyzed, including the use of passive phosphorus samplers. We also set up an experimental design to investigate the role temperature, light and phosphorus on the development of phytoplankton biomass. (2) Secondly, a chemical analysis of the lake’s sediments is carried out resorting to sediment coring and experimentation to measure the potential of phosphorus release under anoxic conditions. (3) Thirdly, the role of temperature and oxygen on phytoplankton composition will be assessed using a statistical modeling approach. We measured temperature and oxygen in several stations of the lake to calibrate these models using autonomous high-frequency sensors. (4) The phytoplankton community is studied both spatially and temporally, at the taxonomic and algal group level. Cyanotoxins are also regularly monitored. Finally, two modeling-based workpackages will focus on (5) analyzing the role of wind in the spatial distribution of the plankton community and physical parameters and (6) developing remote sensing methods for monitoring algal concentrations in this lake. Ultimately, we aim to decipher the relative contribution of wind, nutrients (fluxes and internal release), and environmental variables, to understand the conditions of cyanobacterial blooms emergence
Entanglement of Inhomogeneous Free Bosons and Orthogonal Polynomials
No full textInternational audienceIn this paper, we investigate the ground-state entanglement entropy in inhomogeneous free-boson models in one spatial dimension. We develop a powerful method to extract the leading term in the entanglement scaling, based on the analytic properties of the inhomogeneous potential. This method is applicable to a broad class of models with smooth spatial inhomogeneities. As a case study, we apply this approach for a family of exactly-solvable models characterized by orthogonal polynomials of the Askey scheme, finding a perfect match between the numerical and analytical results
What about working in a profit-with-purpose corporation? Focus on employees' experience
No full textInternational audienceIn view of current societal and environmental challenges, companies are being called upon to consider the impacts of their activities and to actively commit to addressing these issues. To support this goal, several countries (e.g., Canada, Italy, France) have established new legal forms that enable businesses to integrate non-financial objectives, commonly referred to as "profit-with-purpose" corporations. In France, this legal form — known as "société à mission" — has been attracting increasing interest among researchers in management sciences. Introducing a purpose and new objectives implies that employees must engage in implementing these objectives and potentially adjust their activities accordingly. However, none of the current studies have focused on employees and the effects of adopting this legal form on work. This presentation aims to: 1) briefly characterize "profit-with-purpose" corporations with a focus on the French form of the "société à mission"; 2) highlight the positive and negative psychosocial impacts of adopting a purpose on employees' experience. Our analysis is based on findings from interviews and focus groups conducted with employees from four French "sociétés à mission". We will discuss the role of work and organizational psychologists in considering employees in the project of adopting a purpose, and even for all CSR (Corporate Social Responsibility) initiatives
In-soil hydrogen concentration measurements using MONHyTOR.
No full textInternational audienceSoil gas analysis is among the commonly used methods in the early stages of natural hydrogen exploration. While most punctual [H2] measurements can provide information on spatial variation, observing temporal variation requires long-term monitoring. The University of Pau and Adour Countries developed a hydrogen-monitoring instrument called MONHyTOR. It is a passive instrument capable of acquiring [H2], temperature, and relative humidity data with up to 1-s sampling interval at 1-m depth for up to several months in full autonomy.Preliminary field data from multiple sites show that (1) an “installation peak” is almost systematically observed after drilling; (2) measured [H2] is nil most of the times; (3) daily oscillations are present in some datasets; (4) small-amplitude isolated peaks are seemingly related to weather events such as storm and heavy rain. These observations raise the question regarding the influence of water saturation and pressure balance in the atmosphere-soil-instrument system. To understand them, experiments are carried out in a controlled environment using airtight container filled with coarse homogeneous sand with a given water saturation level, where hydrogen is introduced via low-pressure (mbar) injections of 5%-95% H2-N2 mixture. The aim of this study is to see how variations in the pressure balance impact [H2] measurements by MONHyTOR