An elastic plastic damage formulation for concrete: application to elementary and structural tests

Pure elastic damage models or pure elastic plastic constitutive laws are not totally satisfactory to describe the behaviour of concrete. They indeed fail to reproduce the unloading slopes during cyclic loading which define experimentally the value of the damage in the material. When coupled effects are considered, in particular in hydro-mechanical problems, the capability of numerical models to reproduce the unloading behaviour is essential, because an accurate value of the damage, which controls the material permeability, is needed. In the context of very large size calculations that are needed for 3D massive structures heavily reinforced and pre-stressed (such as containment vessels), constitutive relations ought also to be as simple as possible. Here an elastic plastic damage formulation is proposed to circumvent the disadvantages of pure plastic and pure damage approaches. It is based on an isotropic damage model combined with a hardening yield plastic surface in order to reach a compromise as far as simplicity is concerned. Three elementary tests are first considered for validation. A tension test, a cyclic compression test and triaxial tests illustrate the improvements achieved by the coupled law compared to a simple damage model (plastic strains, change of volumetric behaviour, decrease in the elastic slope under hydrostatic pressures). Finally, one structural application is also considered: a concrete column wrapped in a steel tube

Hydraulic behaviour of a representative structural volume for containment buildings

For particular structures like containment buildings of nuclear power plants, the study of the hydraulic behaviour is of great concern. These structures are indeed the third barrier used to protect the environment in case of accidents. The evolution of the leaking rate through the porous medium is closely related to the changes in the permeability during the ageing process of the structure. It is thus essential to know the relation between concrete degradation and the transfer property when the consequences of a mechanical loading on the hydraulic behaviour have to be evaluated. A chained approach is designed for this purpose. The mechanical behaviour is described by an elastic plastic damage formulation, where damage is responsible for the softening evolution while plasticity accounts for the development of irreversible strains. The drying process is evaluated according to a non-linear equation of diffusion. From the knowledge of the damage and the degree of saturation, a relation is proposed to calculate the permeability of concrete. Finally, the non-homogeneous distribution of the hydraulic conductivity is included in the hydraulic problem which is in fact the association of the mass balance equation for gas phase and Darcy law. From this methodology, it is shown how an indicator for the hydraulic flows can be deduced

Lensing Magnification: A novel method to weigh high-redshift clusters and its application to SpARCS

We introduce a novel method to measure the masses of galaxy clusters at high redshift selected from optical and IR Spitzer data via the red-sequence technique. Lyman-break galaxies are used as a well understood, high-redshift background sample allowing mass measurements of lenses at unprecedented high redshifts using weak lensing magnification. By stacking a significant number of clusters at different redshifts with average masses of ~1-3x10^14M_sun, as estimated from their richness, we can calibrate the normalisation of the mass-richness relation. With the current data set (area: 6 deg^2) we detect a magnification signal at the >3-sigma level. There is good agreement between the masses estimated from the richness of the clusters and the average masses estimated from magnification, albeit with large uncertainties. We perform tests that suggest the absence of strong systematic effects and support the robustness of the measurement. This method - when applied to larger data sets in the future - will yield an accurate calibration of the mass-observable relations at z>~1 which will represent an invaluable input for cosmological studies using the galaxy cluster mass function and astrophysical studies of cluster formation. Furthermore this method will probably be the least expensive way to measure masses of large numbers of z>1 clusters detected in future IR-imaging surveys.Comment: 5 pages, 1 figure, 1 table, accepted by ApJL, minor revision

Reconsidération d’Orgnac 3 dans le temps et l’espace : implications pour la reconstruction des origines néandertaliennes – version abrégée

L’un des objectifs importants de la recherche paléoanthropologique et archéologique est de clarifier les données qui restent encore mal cernées du Pléistocène moyen (PM). Combler les lacunes du PM eurasiatique nous permet de mieux comprendre l'évolution comportementale et biologique des humains archaïques, des Néandertaliens, des Denisoviens, et de leurs ancêtres. Orgnac 3, situé en France méditerranéenne, est particulièrement adapté pour aborder ces questions. Cet article présente le site à de nouveaux lecteurs, résume les travaux antérieurs réalisés sur le site et son matériel, et propose différents points de vue fondés sur une nouvelle analyse de son matériel faunique. Sur la base des éléments de démonstration actuellement disponibles, il faut envisager que la séquence d'Orgnac 3 soit probablement beaucoup plus ancienne que ce qui est généralement accepté. Cette vaste séquence pourrait ainsi dater des OIS 12-8, et non seulement des OIS 9-8 comme cela a été traditionnellement proposé. Les dents d'homininés, qui n'ont pas été décrites en détail ni assignées à un taxon, dateraient d'environ 375 à 400 000 ans, période centrale du débat sur la divergence entre les populations néandertalienne, dénisovienne et humaine moderne. Des analyses plus exactes et plus précises du matériel paléontologique, archéologique et géologique d'Orgnac 3 sont nécessaires pour clarifier notre compréhension de l'évolution des homininés pendant le PM.An important aim in paleoanthropological and archaeological research is to clarify the poorly resolved record of the Middle Pleistocene (MP). Filling in the gaps of the Eurasian MP furthers our understanding of the behavioral and biological evolution of archaic humans, Neanderthals, Denisovans and their ancestors. Orgnac 3, located in Mediterranean France, is particularly suited to address these issues. This paper introduces the site to new readers, summarizes the previous work performed on the site and its material, and offers different views based on new analysis of its faunal material. Based on the currently available evidence, the Orgnac 3 sequence is likely far older than previously thought and might date to OISs 12-8, not only 9-8 as traditionally proposed. The hominin teeth, which have not been described in detail or assigned to a taxon, would date to ~375 - 400,000 years ago, the focal period of the Neandertal/Denisovan/modern human population divergence debate. More accurate and precise analyses of Orgnac 3's paleontological, archaeological and geological material are needed to clarify our understanding of hominin evolution during the MP

Rethinking Orgnac 3 in Time and Space: Implications for Reconstructing Neandertal Origins

An important aim in paleoanthropological and archaeological research is to clarify the poorly resolved record of the Middle Pleistocene (MP). Filling in the gaps of the Eurasian MP furthers our understanding of the behavioral and biological evolution of archaic humans, Neanderthals, Denisovans and their ancestors. Orgnac 3, located in Mediterranean France, is particularly suited to address these issues. This paper introduces the site to new readers, summarizes the previous work performed on the site and its material, and offers different views based on new analysis of its faunal material. Based on the currently available evidence, the Orgnac 3 sequence is likely far older than previously thought and might date to OISs 12-8, not only 9-8 as traditionally proposed. The hominin teeth, which have not been described in detail or assigned to a taxon, would date to ~375 - 400,000 years ago, the focal period of the Neandertal/Denisovan/modern human population divergence debate. More accurate and precise analyses of Orgnac 3's paleontological, archaeological and geological material are needed to clarify our understanding of hominin evolution during the MP.L’un des objectifs importants de la recherche paléoanthropologique et archéologique est de clarifier les données qui restent encore mal cernées du Pléistocène moyen (PM). Combler les lacunes du PM eurasiatique nous permet de mieux comprendre l'évolution comportementale et biologique des humains archaïques, des Néandertaliens, des Denisoviens, et de leurs ancêtres. Orgnac 3, situé en France méditerranéenne, est particulièrement adapté pour aborder ces questions. Cet article présente le site à de nouveaux lecteurs, résume les travaux antérieurs réalisés sur le site et son matériel, et propose différents points de vue fondés sur une nouvelle analyse de son matériel faunique. Sur la base des éléments de démonstration actuellement disponibles, il faut envisager que la séquence d'Orgnac 3 soit probablement beaucoup plus ancienne que ce qui est généralement accepté. Cette vaste séquence pourrait ainsi dater des OIS 12-8, et non seulement des OIS 9-8 comme cela a été traditionnellement proposé. Les dents d'homininés, qui n'ont pas été décrites en détail ni assignées à un taxon, dateraient d'environ 375 à 400 000 ans, période centrale du débat sur la divergence entre les populations néandertalienne, dénisovienne et humaine moderne. Des analyses plus exactes et plus précises du matériel paléontologique, archéologique et géologique d'Orgnac 3 sont nécessaires pour clarifier notre compréhension de l'évolution des homininés pendant le PM

Hippocampal GABAergic inhibitory interneurons

In the hippocampus GABAergic local circuit inhibitory interneurons represent only ~10–15% of the total neuronal population; however, their remarkable anatomical and physiological diversity allows them to regulate virtually all aspects of cellular and circuit function. Here we provide an overview of the current state of the field of interneuron research, focusing largely on the hippocampus. We discuss recent advances related to the various cell types, including their development and maturation, expression of subtype-specific voltage- and ligand-gated channels, and their roles in network oscillations. We also discuss recent technological advances and approaches that have permitted high-resolution, subtype-specific examination of their roles in numerous neural circuit disorders and the emerging therapeutic strategies to ameliorate such pathophysiological conditions. The ultimate goal of this review is not only to provide a touchstone for the current state of the field, but to help pave the way for future research by highlighting where gaps in our knowledge exist and how a complete appreciation of their roles will aid in future therapeutic strategies

Magnification by Galaxy Group Dark Matter Halos

We report on the detection of gravitational lensing magnification by a population of galaxy groups, at a significance level of 4.9 sigma. Using X-ray selected groups in the COSMOS 1.64 deg^2 field, and high-redshift Lyman break galaxies as sources, we measure a lensing-induced angular cross-correlation between the samples. After satisfying consistency checks that demonstrate we have indeed detected a magnification signal, and are not suffering from contamination by physical overlap of samples, we proceed to implement an optimally weighted cross-correlation function to further boost the signal to noise of the measurement. Interpreting this optimally weighted measurement allows us to study properties of the lensing groups. We model the full distribution of group masses using a composite-halo approach, considering both the singular isothermal sphere and Navarro-Frenk-White profiles, and find our best fit values to be consistent with those recovered using the weak-lensing shear technique. We argue that future weak-lensing studies will need to incorporate magnification along with shear, both to reduce residual systematics and to make full use of all available source information, in an effort to maximize scientific yield of the observations.Comment: 6 pages, 3 figures, Accepted by Ap

Automated VR therapy for improving positive self-beliefs and psychological well-being in young patients with psychosis: a proof of concept evaluation of Phoenix VR self-confidence therapy

Background: Low self-confidence in patients with psychosis is common. This can lead to higher symptom severity, withdrawal from activities, and low psychological well-being. There are effective psychological techniques to improve positive self-beliefs but these are seldom provided in psychosis services. With young people with lived experience of psychosis we developed a scalable automated VR therapy to enhance positive-self beliefs. Aims: The aim was to conduct a proof of concept clinical test of whether the new VR self-confidence therapy (Phoenix) may increase positive self-beliefs and psychological well-being. Method: Twelve young patients with non-affective psychosis and with low levels of positive self-beliefs participated. Over 6 weeks, patients were provided with a stand-alone VR headset so that they could use Phoenix at home and were offered weekly psychologist meetings. The outcome measures were the Oxford Positive Self Scale (OxPos), Brief Core Schema Scale, and Warwick-Edinburgh Well-being Scale (WEMWBS). Satisfaction, adverse events and side-effects were assessed. Results: Eleven patients provided outcome data. There were very large end-of-treatment improvements in positive self-beliefs (OxPos mean difference = 32.3; 95% CI: 17.3, 47.3; Cohen’s d=3.0) and psychological well-being (WEMWBS mean difference = 11.2; 95% CI: 8.0, 14.3; Cohen’s d=1.5). Patients rated the quality of the VR therapy as: excellent (n=9), good (n=2), fair (n=0), poor (n=0). An average of 5.3 (SD=1.4) appointments were attended. Conclusions: Uptake of the VR intervention was high, satisfaction was high, and side-effects extremely few. There were promising indications of large improvements in positive self-beliefs and psychological well-being. A randomized controlled clinical evaluation is warranted

Randomised controlled trial of automated VR therapy to improve positive self-beliefs and psychological well-being in young people diagnosed with psychosis: a study protocol for the Phoenix VR self-confidence therapy trial

Introduction The confidence of young people diagnosed with psychosis is often low. Positive self-beliefs may be few and negative self-beliefs many. A sense of defeat and failure is common. Young people often withdraw from many aspects of everyday life. Psychological well-being is lowered. Psychological techniques can improve self-confidence, but a shortage of therapists means that very few patients ever receive such help. Virtual reality (VR) offers a potential route out of this impasse. By including a virtual coach, treatment can be automated. As such, delivery of effective therapy is no longer reliant on the availability of therapists. With young people with lived experience, we have developed a staff-assisted automated VR therapy to improve positive self-beliefs (Phoenix). The treatment is based on established cognitive behavioural therapy and positive psychology techniques. A case series indicates that this approach may lead to large improvements in positive self-beliefs and psychological well-being. We now aim to conduct the first randomised controlled evaluation of Phoenix VR. Methods and analysis 80 patients with psychosis, aged between 16 and 30 years old and with low levels of positive self-beliefs, will be recruited from National Health Service (NHS) secondary care services. They will be randomised (1:1) to the Phoenix VR self-confidence therapy added to treatment as usual or treatment as usual. Assessments will be conducted at 0, 6 (post-treatment) and 12 weeks by a researcher blind to allocation. The primary outcome is positive self-beliefs at 6 weeks rated with the Oxford Positive Self Scale. The secondary outcomes are psychiatric symptoms, activity levels and quality of life. All main analyses will be intention to treat. Ethics and dissemination The trial has received ethical approval from the NHS Health Research Authority (22/LO/0273). A key output will be a high-quality VR treatment for patients to improve self-confidence and psychological well-being. Trial registration number ISRCTN10250113

Association Between Frailty and Atrial Fibrillation in Older Adults: The Framingham Heart Study Offspring Cohort

Background: Frailty is associated bidirectionally with cardiovascular disease. However, the relations between frailty and atrial fibrillation (AF) have not been fully elucidated. Methods and Results: Using the FHS (Framingham Heart Study) Offspring cohort, we sought to examine both the association between frailty (2005-2008) and incident AF through 2016 and the association between prevalent AF and frailty status (2011-2014). Frailty was defined using the Fried phenotype. Models adjusted for age, sex, and smoking. Cox proportional hazards models, adjusted for competing risk of death, assessed the association between prevalent frailty and incident AF. Logistic regression models assessed the association between prevalent AF and new-onset frailty. For the incident AF analysis, we included 2053 participants (56% women; mean age, 69.7+/-6.9 years). By Fried criteria, 1018 (50%) were robust, 903 (44%) were prefrail, and 132 (6%) were frail. In total, 306 incident cases of AF occurred during an average 9.2 (SD, 3.1) follow-up years. After adjustment, there was no statistically significant association between prevalent frailty status and incident AF (prefrail versus robust: hazard ratio [HR], 1.22 [95% CI, 0.95-1.55]; frail versus robust: HR, 0.92 [95% CI, 0.57-1.47]). At follow-up, there were 111 new cases of frailty. After adjustment, there was no statistically significant association between prevalent AF and new-onset frailty (odds ratio, 0.48 [95% CI, 0.17-1.36]). Conclusions: Although a bidirectional association between frailty and cardiovascular disease has been suggested, we did not find evidence of an association between frailty and AF. Our findings may be limited by sample size and should be further explored in other populations