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Bottom and Top Internodes Subjected to Interactions with Genotype in Miscanthus: Impact of Biochemical Composition and Anatomy on Stem-Based Composites Mechanical Properties
No full textInternational audienceMiscanthus (Miscanthus Andersson) is a perennial grass for which biomaterials market has taken growing interest. Our objective was to evaluate the effect of stem internode position in Miscanthus × giganteus and Miscanthus sinensis and the impact of its anatomy and biochemical composition on internode-based composites' mechanical properties. Stems' bottom and top internodes were sampled for two genotypes of each species in two different years and separately added to a polypropylene matrix, and the mechanical properties of the internode-reinforced composites were measured. Before composite production, the internodes were extensively phenotyped for biochemical composition and anatomy. Stems' bottom and top internode-based composites yielded different modulus (3203 and 2988 MPa, respectively), while tensile strength was similar (36.4 and 36.5 MPa, respectively). Significant genotype × internode interactions occurred for most variables, mainly due to differences among species, since both Miscanthus sinensis clones proved to be more stable than both Miscanthus × giganteus clones for modulus (4% and 10.2%, respectively). Regarding tensile strength, the species showed small but opposite differences between internodes. Tensile strength and modulus were rather close only in the top internodes, where good mechanical properties were associated with the lowest values of vascular bundles number and section area and highest parenchyma tissue, while opposite results were obtained in the bottom ones, only for tensile strength. Miscanthus sinensis species proved to be interesting for the stability improvement of composite mechanical properties. It appears essential for experimental purposes to stratify the sampling by internode in order to be representative of the whole stem
Silicate–sulfide interaction within quenched melts of space weathered Ryugu grains
No full textInternational audienceThe first few microns of the surface of airless bodies are subject to severe changes due to the harsh environment of space, known as space weathering. The Hayabusa2 sample return mission from the asteroid Ryugu provides the first opportunity to study these effects on a carbonaceous and hydrated body. Understanding the structural and chemical changes that occur in the space weathered layers of Ryugu is crucial to correctly interpreting the mechanisms involved in such processes. This study employs transmission electron microscopy to achieve the spatial resolution necessary to analyze the nanoscale heterogeneities in these modified layers. The chemical analyses indicate that features present are likely to represent the spattering of a Ryugu‐like material, possibly from a different lithology of the asteroid. However, such material appears to be completely dehydroxylated and depleted in sulfur by approximately 20%. Furthermore, the nanoscale dispersion of vesicles and rounded nanosulfides found in these melt layers helps to estimate the temperatures (>1300°C) and the time scales (<10−8 s) involved in their formation. In addition, this study describes and discusses a unique spherical feature not previously observed in Ryugu samples. The 3 μm‐sized object shows strong similarities to microchondrules observed in some carbonaceous (CM2) and ordinary chondrites, suggesting a divergent thermal history from that of the melt layers
Hungry Minds: Provoking and Sustaining Curiosity in Organizations
No full textInternational audiencePrevious research has examined the origins and benefits of curiosity, attributing it primarily to an inherent human capacity. However, there has been limited theoretical or empirical exploration of how organizations can shape work environments to encourage employees to be more curious. This article pioneers a fresh perspective by examining how curiosity can be constantly provoked and sustained in organizations. Using an inductive study of a highly creative organization in the gastronomy industry, we discover two types of provocations: codified and uncodified. Together, these provocations encourage individuals to challenge each other and consider novel interpretations. Moreover, our findings reveal a specific mechanism – ‘stretching’– aimed at sustaining the curiosity engine by continually renewing provocations and preventing them from potential rigidity and monotony. We also discover “relaxing practices” which help to alleviate the curiosity pressure among team members. Through the dynamic interplay between provocations and ‘stretching’, curiosity becomes an agentic force that extends beyond the confines of individual minds to impact the entire organization. Our discoveries reveal new research puzzles on curiosity, likely to stimulate further theorizing regarding its role in organizations
Quand la disparition des services publics alimente le vote populiste
No full texthttps://theconversation.com/quand-la-disparition-des-services-publics-alimente-le-vote-populiste-255531Populist parties made spectacular gains between 2002 and 2022. While multiple factors can explain this, the deterioration or disappearance of public services in many rural or peripheral areas plays a significant role. This is shown by a study analyzing the relationship between the disappearance of public services and changes in voting behavior in France
Knowledge withholding by and from leaders: an emerging theoretical model
No full textInternational audiencePurpose This study aims to explore the reasons why leaders withhold knowledge by analyzing various types of relational contexts in which knowledge is withheld. Design/methodology/approach This study is a content analysis of the memoirs of five reputed US general and flag officers. After analyzing 1,853 pages, the researchers collected 246 knowledge-withholding units and identified eight relational contexts. They build on interdependence, social identity and social exchange theories to develop an emerging model. Findings The data indicate (a) conflicting interests increase knowledge withholding, particularly among weaker parties; (b) common goals increase knowledge withholding when failure imposes greater risk, and when there is a lack of trust (c) parties may simultaneously experience competing and common goals in which behavior may be driven by their strongest (social) identity. Originality/value The insights indicate that knowledge withholding may be used as an effective leadership tool
Impact of 2 Months Exercise Training on Glycaemic Metrics on Days with and Without Exercise in Adults with Type 1 Diabetes: A Pilot Single-Arm Study.
No full textInternational audienceAims Implementing exercise programs in individuals with type 1 diabetes (T1D) may precipitate glycaemic fluctuations. A better understanding of these fluctuations is essential for developing appropriate glucose management strategies. We aimed to assess glycaemic excursions and their progression during a 2-month training program, comparing fluctuations around exercise sessions with those of non-exercising days.Methods Nineteen (13 female) adults with T1D participated in 2-3 supervised 90-minute combined (aerobic/strength) exercise sessions per week, over 2 months. Glycaemic excursions (continuous glucose monitoring) were measured during specific periods (24-hour, nocturnal; periods before, during, after exercise sessions) and compared between exercise and non-exercise days (linear mixed models, logistic regressions).Results Nights following exercise sessions showed a reduced risk of hyperglycaemia (>10.0 mmol·L-1) vs. non-exercise nights. This difference diminished over the weeks of training, alongside a progressive increase in the risk of time > 16.7 mmol·L-1 during the early and late recovery phases of exercise. Overall, regardless of exercise session occurrence, level 1 and 2 nocturnal hypoglycaemic risk increased as the training program progressed.Conclusions Initially, acute exercise sessions reduced nocturnal hyperglycaemia without increasing hypoglycaemia. However, over time, the risk of nocturnal hypoglycaemia increased, highlighting the need for vigilant glycaemic supervision, particularly at night, even on non-exercise days
Setting public health guidelines for chemicals in indoor settled dust. First achievements and steps to come: the case of lead
No full textInternational audienceHealth based guidelines for environmental concentrations of chemicals are designed to prevent harmful chemical exposures. However, none exists for indoor settled dust, despite its ingestion being a documented pathway of exposure, for certain chemicals. The objective of this paper is to present the derivation of a health-based indoor settled dust guideline (ISDG) for lead. The guideline was developed to protect a specific fraction of the most vulnerable population against the most sensitive effect, taking into account other exposure pathways. It is calculated from a toxicological reference value, body weight, and the mass of ingested dust. The most vulnerable population is young children, and the corresponding critical effect is a loss of IQ points, with a toxicity reference value of 0.5 µg.kgbw-1.d-1. Assuming that 80% of the exposure for the most affected individuals comes from dust ingestion, the ISDG for protecting 90, 95 or 95% of young children are 43, 33 and 20 µg.gdust-1, respectively. These values are consistently lower than the concentrations that would trigger lead poisoning screening. The main uncertainties lie in the estimations of the amount of ingested dust. This ISDG could contribute to environmental management efforts to prevent or reduce lead exposures
Alginate versus Chitosan for Templating Growth and Shaping HKUST‐1 as Porous CO2‐Adsorbent Beads
No full textInternational audienceThis study aims at elucidating the role of the polysaccharide skeleton (alginate versus chitosan) during the growth and shaping of HKUST‐1 as porous beads. Although the two biopolymers afford an open porous hydrogel network, the freeze‐drying step was crucial with water medium being inappropriate to preserve the crystalline framework of HKUST‐1. Alternatively, drying in ethanol circumvented this drawback by keeping intact the structure of HKUST‐1. However, a contrasting behavior was observed in the resulting polysaccharide@HKUST‐1 beads, as HKUST‐1 grown in alginate underwent a dramatic collapse, whereas self‐standing, open porous microspheres could be obtained using the chitosan templating route. The resulting chitosan@HKUST‐1 cryogel displays an enhanced CO2 capture (2.67 mmol.g−1) compared to its analogs shaped by alginate, making consequently chitosan a better option for structuring MOF‐based adsorbents
Evaluation of iron oxide coatings as electrocatalysts for oxygen evolution reaction obtained via electrodeposition and magnetron sputtering
No full textInternational audienceIn this work, the electrocatalytic activity of hematite with a porous and compact structure was investigated in the process of oxygen evolution. Porous coatings were synthesized using potentiodynamic ElectroDeposition (ED) and thermal treatment, while compact coatings were synthesized by Magnetron Sputtering (MS). Electrocatalytic evaluation of the coatings showed that there is no significant difference with respect to the overpotential of the reaction onset potential, which is 342–353 mV for electrodeposited samples and 341–355 mV for those obtained by the MS method. However, the advantage of compact coatings has emerged at higher current density values, when the activity of porous coatings faces limitations due to diffusion from and into the pores. Calculations of the coefficient b of the Tafel equation revealed the superiority of porous structures (avg. 48 mV⋅dec-1) at the beginning of the reaction over compact coatings (avg. 56 mV⋅dec-1)