Fatigue failure maps of heterogeneous materials

International audienceIn this paper, so-called fatigue failure maps are studied as a function of initial flaw size distributions. The main cause of fatigue failure for brittle materials, and of fatigue initiation for ductile materials, is that initial flaws become critical. Fatigue failure maps where the number of cycles to initiation for a given failure probability is plotted for various flaw size distributions are a means of characterizing the influence of the initial flaw distribution on fatigue crack initiation. The results are applied to fatigue failure of austempered spheroidal graphite cast iron

Factors affecting mechanical (nociceptive) thresholds in piglets

AbstractObjectiveTo evaluate the stability and repeatability of measures of mechanical (nociceptive) thresholds in piglets and to examine potentially confounding factors when using a hand held algometer.Study designDescriptive, prospective cohort.AnimalsForty-four piglets from four litters, weighing 4.6 ± 1.0 kg (mean ± SD) at 2 weeks of age.MethodsMechanical thresholds were measured twice on each of 2 days during the first and second week of life. Data were analyzed using a repeated measures design to test the effects of behavior prior to testing, sex, week, day within week, and repetition within day. The effect of body weight and the interaction between piglet weight and behaviour were also tested. Piglet was entered into the model as a random effect as an additional test of repeatability. The effect of repeated testing was used to test the stability of measures. Pearson correlations between repeated measures were used to test the repeatability of measures. Variance component analysis was used to describe the variability in the data.ResultsVariance component analysis indicated that piglet explained only 17% of the variance in the data. All variables in the model (behaviour prior to testing, sex, week, day within week, repetition within day, body weight, the interaction between body weight and behaviour, piglet identity) except sex had a significant effect (p < 0.04 for all). Correlations between repeated measures increased from the first to the second week.Conclusions and Clinical relevanceRepeatability was acceptable only during the second week of testing and measures changed with repeated testing and increased with increasing piglet weight, indicating that time (age) and animal body weight should be taken into account when measuring mechanical (nociceptive) thresholds in piglets. Mechanical (nociceptive) thresholds can be used both for testing the efficacy of anaesthetics and analgesics, and for assessing hyperalgesia in chronic pain states in research and clinical settings

Breast cancer: a randomized controlled trial assessing the effect of a decision aid on mammography screening uptake: study protocol

IntroductionBreast cancer (BC) is the primary cancer among women. The World Health Organization recommends a bilateral screening mammogram every 2 years for women aged 50 to 74 years. However, it has been shown that there is an absence of information about the benefits and risks of screening. Shared medical decision-making is important to ensure patients are involved in the decision process. Decision aids can facilitative this decision-making process. This article presents a protocol to evaluate the effect of a decision aid on participation rates in the French organized BC screening program.Methods and analysisDesign and setting. The design is a 2 arm randomized controlled study, performed in the Pays de la Loire region (French West Coast). Randomization will be based on general medicine practices (Primary Care).ParticipantsWomen aged between 50 and 74 years, eligible for BC screening. In this region, there are 75000 women, and 2800 general practitioners eligible for recruitment.InterventionIn the « Decision aid for organized cancer screening » arm, the intervention will distribute invitation letters to eligible women combined with the provision of decision aid to these women and their general practitioners and an incentive to implement shared medical decision-making. In the « Standard organized cancer screening » arm, only the screening invitation will be sent to eligible women.Primary endpointBC screening participation rates will be assessed after an 18-month follow-up period.Statistical analysisIn this non-inferiority trial, the percentage of women who are up-to-date with their screening at 18 months after the intervention will be compared across arms using a generalized mixed linear model.DiscussionThe research team expect to demonstrate that providing a better explanation of the benefits and risks of BC screening is not at odds with screening participation. The study results should help policy makers thinking about implementing shared medical decision-making within the framework of organized BC screening programs in the future.Ethics and disseminationOn 6 December 2021, the protocol received a favorable opinion from the French Committee for the Protection of Persons (2021-A01583-38). This study is registered with ClinicalTrials.gov, number NCT05607849. (Version 1, November 7, 2022; https://www.clinicaltrials.gov/ct2/show/NCT05607849). The study findings will be used for publication in peer-reviewed scientific journals and presentations in scientific meetings

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M&gt;70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0&lt;e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Impact des pratiques humaines lors des soins de prophylaxie

National audienceII existe à l'heure actuelle très peu d'éléments sur la manière la plus souhaitable d'approcher des chevaux lors des soins de prophylaxie. Lorsqu'il s'approche, l'humain prend des postures, peut produire des signaux vocaux et fixer ou non son attention sur l'animal à travers la direction de son regard. L'objectif de nos recherches vise donc à déterminer comment se comporter avec des chevaux, jeunes et adultes, lors des conduites de prophylaxie. Cette étude a été réalisée à la station expérimentale de Chamberet sur 68 chevaux, incluant 46 juments non gestantes et 22 poulains âgés de 2 et 4 ans. Sept manipulateurs, familiers des chevaux ont été impliqués : ils devaient réaliser la vermifugation dans une cage de contention selon leurs pratiques habituelles, l'objectif étant d'examiner si la technique du manipulateur influence les réactions des chevaux. Les premiers résultats indiquent que cette manipulation, bien que courte et indolore, est perçue globalement négativement par l'animal et que la manipulation dure plus longtemps chez les plus jeunes individus. Il apparait également que les chevaux présentent des profils de réaction différents en fonction de l'individu humain réalisant l'intervention. A partir de ces données préliminaires, il apparait que l'effet du manipulateur soit majeur : son mode de contention, son attitude envers l'animal ou encore sa rapidité d'intervention seraient impliqués. Ces recherches ont des implications pratiques évidentes pour les professionnels intervenant ponctuellement sur le cheval

Impact des pratiques humaines lors des soins de prophylaxie

National audienceII existe à l'heure actuelle très peu d'éléments sur la manière la plus souhaitable d'approcher des chevaux lors des soins de prophylaxie. Lorsqu'il s'approche, l'humain prend des postures, peut produire des signaux vocaux et fixer ou non son attention sur l'animal à travers la direction de son regard. L'objectif de nos recherches vise donc à déterminer comment se comporter avec des chevaux, jeunes et adultes, lors des conduites de prophylaxie. Cette étude a été réalisée à la station expérimentale de Chamberet sur 68 chevaux, incluant 46 juments non gestantes et 22 poulains âgés de 2 et 4 ans. Sept manipulateurs, familiers des chevaux ont été impliqués : ils devaient réaliser la vermifugation dans une cage de contention selon leurs pratiques habituelles, l'objectif étant d'examiner si la technique du manipulateur influence les réactions des chevaux. Les premiers résultats indiquent que cette manipulation, bien que courte et indolore, est perçue globalement négativement par l'animal et que la manipulation dure plus longtemps chez les plus jeunes individus. Il apparait également que les chevaux présentent des profils de réaction différents en fonction de l'individu humain réalisant l'intervention. A partir de ces données préliminaires, il apparait que l'effet du manipulateur soit majeur : son mode de contention, son attitude envers l'animal ou encore sa rapidité d'intervention seraient impliqués. Ces recherches ont des implications pratiques évidentes pour les professionnels intervenant ponctuellement sur le cheval

Retention of individual recognition in chicks and the effects of social experience

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Positive affects in lambs: appeasing effects of stroking

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