Individual exploratory responses are not repeatable across time or context for four species of food-storing corvid.

Exploration is among one of the most studied of animal personality traits (i.e., individual-level behavioural responses repeatable across time and contexts). However, not all species show clear evidence of this personality trait, and this is particularly so for members of the Corvidae family. We assessed the exploratory behaviour of four food-caching corvid species: pinyon jays (Gymnorhinus cyanocephalus), Clark's nutcrackers (Nucifraga columbiana), California scrub jays (Aphelocoma californica), and black-billed magpies (Pica hudsonia). Contextual repeatability was assessed through examining behavioural measures during the Novel Environment task and the Novel Object task, whereas temporal repeatability was assessed by examining changes in these measures over repeated trials. Our results suggest that, for corvids, an individual's exploratory behaviour was not repeatable across contexts or over time. Hence, we found no evidence that exploration constitutes a personality trait for these species of corvid. We did find differences in exploratory behaviour, at a species level, that may be explained by relative reliance on cached food

Metal dusting of Inconel 625 obtained by laser beam melting: Effect of manufacturing process and hot isostatic pressure treatment

Metal dusting resistance of Inconel 625 alloy obtained by laser beam melting (LBM), compared to wrought alloy 625 was assessed during 9 500 h at 610 °C. Whatever the manufacturing process, the mass variations were very small when the systems were ground thanks to the formation of a uniform protective chromia layer. However, the high surface roughness was shown to be detrimental as the waviness favoured the local formation of an unprotective spinel oxide. Hot isostatic pressure (HIP) treatment recrystallized the alloy and increased its grain size. This reduced chromium diffusion towards the surface, explaining the poorer resistance of the LBM + HIP system

A comparison of the high-temperature oxidation behaviour of conventional wrought and laser beam melted Inconel 625

The microstructure and oxidation resistance of Laser Beam Melted (LBM) and Conventionally Manufactured (CM) Inconel 625 alloys were studied at 900 °C and 1050 °C. The microstructure of the LBM samples was cellular, with Nb and Mo segregations located at the cell walls. At 900 °C, the oxidation rate was similar for both materials but was clearly higher for the LBM material at 1050 °C. This high oxidation rate induced poor oxide scale compactness, void formation in the subsurface region and the formation of a high amount of Nb1.5Cr0.5O4 at the alloy-oxide interface

Trialling meta-research in comparative cognition: claims and statistical inference in animal physical cognition

Scientific disciplines face concerns about replicability and statistical inference, and these concerns are also relevant in animal cognition research. This paper presents a first attempt to assess how researchers make and publish claims about animal physical cognition, and the statistical inferences they use to support them. We surveyed 116 published experiments from 63 papers on physical cognition, covering 43 different species. The most common tasks in our sample were trap-tube tasks (14 papers), other tool use tasks (13 papers), means-end understanding and string-pulling tasks (11 papers), object choice and object permanence tasks (9 papers) and access tasks (5 papers). This sample is not representative of the full scope of physical cognition research; however, it does provide data on the types of statistical design and publication decisions researchers have adopted. Across the 116 experiments, the median sample size was 7. Depending on the definitions we used, we estimated that between 44% and 59% of our sample of papers made positive claims about animals’ physical cognitive abilities, between 24% and 46% made inconclusive claims, and between 10% and 17% made negative claims. Several failures of animals to pass physical cognition tasks were reported. Although our measures had low inter-observer reliability, these findings show that negative results can and have been published in the field. However, publication bias is still present, and consistent with this, we observed a drop in the frequency of p-values above .05. This suggests that some non-significant results have not been published. More promisingly, we found that researchers are likely making many correct statistical inferences at the individual-level. The strength of evidence of statistical effects at the group-level was weaker, and its p-value distribution was consistent with some effect sizes being overestimated. Studies such as ours can form part of a wider investigation into statistical reliability in comparative cognition. However, future work should focus on developing the validity and reliability of the measurements they use, and we offer some starting points

On the importance of accounting for alternative foraging tactics when assessing cognitive performance in wild animals

Research Highlight: Reichert, S., Morand-Ferron, J., Kulahci, I. G., Firth, J. A., Davidson, G. L., Crofts, S. J., & Quinn, J. L. (2021) Cognition and covariance in the producer-scrounger game. Journal of Animal Ecology, . When foraging in groups, individuals can either acquire their own resources, as producers, or profit from the work of other individuals, as scroungers. Individuals vary in how much they rely on one foraging tactic over the other. Yet, each of these foraging tactics presents unique cognitive challenges. Using a field experiment with a mixed-species flock of birds, Reichert et al. (2021) investigated how production learning (i.e. successfully feeding from their assigned rewarded feeder) and scrounging propensity (i.e. collecting food from a non-assigned feeders by following another individual) are related at an individual level, as well as the repeatability of both production learning and scrounging propensity. The authors show that overall, (a) individuals learned to scrounge, (b) individuals who rely more on scrounging took longer to learn their assigned feeder and (c) variation in each cognitive trait was mostly explained by individual behavioural flexibility rather than by consistent differences between individuals. Since learning was negatively correlated with the use of an alternative foraging tactic (i.e. scrounging), results of this study also suggest that individual choice of foraging tactics should be considered when evaluating cognitive abilities in wild animals

Etude et caractérisation de la résistance à la carburation pulvérulente d'un superalliage à base de nickel obtenu par fabrication additive

Hydrogen is industrially obtained from two main reactions, the steam methane reforming (SMR) reaction and the water gas shift (WGS) reaction. In addition to H2, CO and CO2 are produced during this process. This leads to the formation of an atmosphere composed of H2, CO, CO2, CH4 and H2O. When exposed to this gas mixture, iron- and nickel-based alloys may be subjected to metal dusting, a catastrophic form of corrosion by carbon that takes place between 400 °C and 800 °C in highly carburising atmospheres (carbon activity, aC >> 1) with a low oxygen partial pressure. This phenomenon leads to the disintegration of metallic materials into a dust of fine metallic particles, oxides, carbides and graphitic carbon. When alloys form a protective oxide scale, metal dusting results in pits whose formation begins at the defects of the oxide scale. To intensify the production of hydrogen and reduce the size of the installations, heat exchanges must be improved and smaller reactors built. In order to do so, intricate geometries have been developed that combine small counter current tubes and thin walls to optimize heat exchange. Additive manufacturing techniques and especially power bed fusion enables the construction of such complex geometries. However, it is likely that the metallurgical differences induced by the LBM process have an influence on the metal dusting resistance. In addition, the local nature of the metal dusting attack could be emphasized by the surface defects or inhomogeneities resulting from additive manufacturing. This work compares the metal dusting resistance of wrought and additive manufactured Inconel 625 taking into account the surface roughness and defects. It also studies the influence of a hot isostatic pressure treatment (HIP: 3 h at 1050 °C under 1020 bar of Ar) and the microstructure it induces. Finally, a NiAl coating on Inconel 625 is tested under metal dusting conditions. The studied systems are placed within a rig in a gas mixture composed of 48%H2-9%CO-6%CO2 -3%CH4-34%H2, at 610 °C for 9 500 h in total. The mass variation and the formation of pits are monitored every 500 h. Whatever the manufacturing process, the mass variations are very small when the systems are ground: the formation of a uniform chromia layer protects the alloy from metal dusting. However, the surface roughness is detrimental for corrosion resistance as the waviness favours the formation of an unprotective spinel oxide. The HIP treatment recrystallizes the alloy and the 3 h heat treatment increases the grain size. This reduces chromium diffusion towards the surface compared to the LBM system, explaining the poor resistance of the LBM + HIP system. Whatever the manufacturing process, the surface defects or the microstructure, NiAl coating protects the alloy of any metal dusting corrosion.Le dihydrogène est obtenu industriellement via la réaction de SMR (Steam Methane Reforming) associée à la réaction de WGS (Water Gas Shift), à partir de méthane et d’eau. En plus de l’hydrogène, du CO et du CO2 sont produits durant ce procédé. L’atmosphère résultante est donc composée de H2-CO-CO2-CH4-H2O, son activité en carbone est très supérieure à 1 et sa pression partielle en dioxygène très faible (10-24 bar). Les alliages métalliques exposés à cette atmosphère, dans une plage de température de 400°C à 800°C sont susceptibles d’être attaqués par metal dusting. Cette corrosion provoque la désintégration de l’alliage en une poussière de fines particules métalliques, de carbone graphitique, appelée « coke », de carbures et d’oxydes. Quand les alliages forment une couche d’oxyde protectrice, le metal dusting s’initie aux défauts de cette couche d’oxyde et forme des piqûres. Afin d’intensifier la production d’hydrogène et de réduire la taille des installations, l’échange de chaleur doit être amélioré et de plus petits doivent être construits. Pour cela des géométries complexes, combinant un réacteur à contre-courant ainsi que des parois fines sont conçues. La fabrication additive et notamment la fusion laser sur lit de poudre (ou LBM) permet la construction de telles pièces. Toutefois, il est possible que les différences métallurgiques induites par ce nouveau procédé de fabrication aient une influence sur la résistance au metal dusting des alliages métalliques. De plus la nature locale de l’attaque par metal dusting pourrait être exacerbée par les défauts et inhomogénéités rencontrées en fabrication additive. Ce travail compare la résistance au metal dusting d’un superalliage à base de nickel, l’Inconel 625 obtenu par forgeage ou par fabrication additive. Il étudie également l’influence d’un traitement de compression isostatique à chaud (CIC: 3 h à 1050 °C sous 1020 bar d’Ar) et de la microstructure qui en résulte. Enfin un revêtement NiAl est testé en conditions propices au metal dusting. Les systèmes étudiés sont placés dans une enceinte expérimentale où la composition gazeuse est la suivante : 48%H2-9%CO-6%CO2 -3%CH4-34%H2, à 610 °C pendant 9 500 h au total. La variation de masse des échantillons ainsi que la formation de piqûres sont suivies toutes les 500 h. Quel que soit le procédé de fabrication, les variations de masse sont très faibles quand les systèmes sont polis : la formation d’une couche de chromine uniforme en surface protège l’alliage de l’attaque par metal dusting. En revanche, la rugosité de surface est néfaste pour la résistance à la corrosion car elle favorise la formation d’oxydes non protecteurs. Le traitement CIC recristallise l’alliage et les trois heures de maintien en température permettent l’augmentation de la taille de grains. Cela diminue la diffusion du chrome vers la surface par rapport au système LBM expliquant le mauvais comportement du système LBM + CIC. Quel que soit le procédé de fabrication, les défauts de surface, la microstructure ou la géométrie des échantillons, le revêtement NiAl protège l’alliage de toute dégradation par metal dusting

Study and caracterisation of the resistance to metal dusting of a nickel-based surperalloy obtained by additive manufacturing

Le dihydrogène est obtenu industriellement via la réaction de SMR (Steam Methane Reforming) associée à la réaction de WGS (Water Gas Shift), à partir de méthane et d’eau. En plus de l’hydrogène, du CO et du CO2 sont produits durant ce procédé. L’atmosphère résultante est donc composée de H2-CO-CO2-CH4-H2O, son activité en carbone est très supérieure à 1 et sa pression partielle en dioxygène très faible (10-24 bar). Les alliages métalliques exposés à cette atmosphère, dans une plage de température de 400°C à 800°C sont susceptibles d’être attaqués par metal dusting. Cette corrosion provoque la désintégration de l’alliage en une poussière de fines particules métalliques, de carbone graphitique, appelée « coke », de carbures et d’oxydes. Quand les alliages forment une couche d’oxyde protectrice, le metal dusting s’initie aux défauts de cette couche d’oxyde et forme des piqûres. Afin d’intensifier la production d’hydrogène et de réduire la taille des installations, l’échange de chaleur doit être amélioré et de plus petits doivent être construits. Pour cela des géométries complexes, combinant un réacteur à contre-courant ainsi que des parois fines sont conçues. La fabrication additive et notamment la fusion laser sur lit de poudre (ou LBM) permet la construction de telles pièces. Toutefois, il est possible que les différences métallurgiques induites par ce nouveau procédé de fabrication aient une influence sur la résistance au metal dusting des alliages métalliques. De plus la nature locale de l’attaque par metal dusting pourrait être exacerbée par les défauts et inhomogénéités rencontrées en fabrication additive. Ce travail compare la résistance au metal dusting d’un superalliage à base de nickel, l’Inconel 625 obtenu par forgeage ou par fabrication additive. Il étudie également l’influence d’un traitement de compression isostatique à chaud (CIC: 3 h à 1050 °C sous 1020 bar d’Ar) et de la microstructure qui en résulte. Enfin un revêtement NiAl est testé en conditions propices au metal dusting. Les systèmes étudiés sont placés dans une enceinte expérimentale où la composition gazeuse est la suivante : 48%H2-9%CO-6%CO2 -3%CH4-34%H2, à 610 °C pendant 9 500 h au total. La variation de masse des échantillons ainsi que la formation de piqûres sont suivies toutes les 500 h. Quel que soit le procédé de fabrication, les variations de masse sont très faibles quand les systèmes sont polis : la formation d’une couche de chromine uniforme en surface protège l’alliage de l’attaque par metal dusting. En revanche, la rugosité de surface est néfaste pour la résistance à la corrosion car elle favorise la formation d’oxydes non protecteurs. Le traitement CIC recristallise l’alliage et les trois heures de maintien en température permettent l’augmentation de la taille de grains. Cela diminue la diffusion du chrome vers la surface par rapport au système LBM expliquant le mauvais comportement du système LBM + CIC. Quel que soit le procédé de fabrication, les défauts de surface, la microstructure ou la géométrie des échantillons, le revêtement NiAl protège l’alliage de toute dégradation par metal dusting.Hydrogen is industrially obtained from two main reactions, the steam methane reforming (SMR) reaction and the water gas shift (WGS) reaction. In addition to H2, CO and CO2 are produced during this process. This leads to the formation of an atmosphere composed of H2, CO, CO2, CH4 and H2O. When exposed to this gas mixture, iron- and nickel-based alloys may be subjected to metal dusting, a catastrophic form of corrosion by carbon that takes place between 400 °C and 800 °C in highly carburising atmospheres (carbon activity, aC >> 1) with a low oxygen partial pressure. This phenomenon leads to the disintegration of metallic materials into a dust of fine metallic particles, oxides, carbides and graphitic carbon. When alloys form a protective oxide scale, metal dusting results in pits whose formation begins at the defects of the oxide scale. To intensify the production of hydrogen and reduce the size of the installations, heat exchanges must be improved and smaller reactors built. In order to do so, intricate geometries have been developed that combine small counter current tubes and thin walls to optimize heat exchange. Additive manufacturing techniques and especially power bed fusion enables the construction of such complex geometries. However, it is likely that the metallurgical differences induced by the LBM process have an influence on the metal dusting resistance. In addition, the local nature of the metal dusting attack could be emphasized by the surface defects or inhomogeneities resulting from additive manufacturing. This work compares the metal dusting resistance of wrought and additive manufactured Inconel 625 taking into account the surface roughness and defects. It also studies the influence of a hot isostatic pressure treatment (HIP: 3 h at 1050 °C under 1020 bar of Ar) and the microstructure it induces. Finally, a NiAl coating on Inconel 625 is tested under metal dusting conditions. The studied systems are placed within a rig in a gas mixture composed of 48%H2-9%CO-6%CO2 -3%CH4-34%H2, at 610 °C for 9 500 h in total. The mass variation and the formation of pits are monitored every 500 h. Whatever the manufacturing process, the mass variations are very small when the systems are ground: the formation of a uniform chromia layer protects the alloy from metal dusting. However, the surface roughness is detrimental for corrosion resistance as the waviness favours the formation of an unprotective spinel oxide. The HIP treatment recrystallizes the alloy and the 3 h heat treatment increases the grain size. This reduces chromium diffusion towards the surface compared to the LBM system, explaining the poor resistance of the LBM + HIP system. Whatever the manufacturing process, the surface defects or the microstructure, NiAl coating protects the alloy of any metal dusting corrosion

Améliorer la santé des Parisiens : deux outils d’aide à la décision pour lutter contre les inégalités de santé

The Paris Environmental Health Service has developed two management tools to prioritize, guide and assess public action in the area of ​​environmental health. The first is a cartographic tool which identifies the areas of accumulation of disadvantages, by means of indicators mapped on a fine spatial scale, relating to environmental nuisances (air pollution, noise, habitat at risk, lack of vegetation), the vulnerabilities of the population (age, state of health, income) and the lack of urban amenities (accessibility to green spaces and general practitioners). It made it possible to identify sectors in which action should be taken as a priority to reduce health inequalities. The second tool is the health impact assessment (HIA) approach applied to urban development projects, for example in the “Gare des Mines” sector located in the north east of Paris. This approach aims to assess the potential effects of an urban project on health and to produce recommendations for decision-makers by bringing together the various stakeholders and involving the inhabitants. These two complementary decision-making support tools also make it possible to improve cross-functionality within departments and with external partners

Social information used to elicit cache protection differs between pinyon jays and Clark’s nutcrackers

Behavioral plasticity can be described as the ability to adjust behavior depending on environmental information. We used a food-storing (caching) paradigm, during which individuals either ate or cached food under different conditions, to investigate whether they could adjust their caching behavior when observed by conspecifics and heterospecifics and which social cues they used to elicit these behavioral changes. We examined the location and number of caches made by two corvid species differing in sociality: highly social pinyon jays (Gymnorhinus cyanocephalus) and less social Clark’s nutcrackers (Nucifraga columbiana). Although pinyon jays cached a similar amount of food across conditions, they allocated significantly more caches to areas less accessible to the observer. Nutcrackers, however, significantly reduced the number of seeds cached when another nutcracker was present in comparison to when they cached alone. Both species relied on different social cues to elicit re-caching: pinyon jays responded to the amount of time the observer spent close to the caching locations, whereas nutcrackers responded to the amount of time the observer spent pilfering their caches. The differences in cache protection behaviors and the social cues eliciting them may be explained by the species’ social organization. Pinyon jays may only adjust their caching behavior when necessary, as they are often surrounded by other individuals. Being less social, Clark’s nutcrackers reduce their caching when observed, as they have more opportunities to cache alone and may resort to additional cache protection when experiencing pilferage. Overall, our results provide insight into understanding how pressures associated with the social environment may influence foraging behaviors