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The effective equilibrium climate sensitivity is generally assumed to be constant in climate change studies, whereas it may vary due to different mechanisms. This study assesses the importance of the different types of state dependencies of the radiative feedbacks for constraining climate projections from the historical record. In transition, the radiative feedbacks may vary with the changes in the warming pattern due to inhomogeneous ocean heat uptake. They may also vary in equilibrium due to their dependence on both temperature and CO2 concentration. A two-layer energy balance model (EBM) that accounts for these effects is shown to improve the representation of any CO2 pathway for the CMIP5 ensemble. Neglecting the nonlinear effects in constraint studies of climate projections from the historical record may induce errors in the estimated future warming. The EBM framework is used to study these errors for three characteristic CO2 pathways. The results show that the pattern effect of ocean heat uptake is not of major importance by inducing a median error of roughly −2% for a high-emission scenario. In contrast, assuming a log-linear CO2–ERF relationship and neglecting the equilibrium-state dependencies induce a larger median error of roughly −10%. This median error is likely due to the non-log-linear dependency of the instantaneous (nonadjusted) forcing, suggesting that the equilibrium-state dependencies do not induce any systematic error. However, they contribute to increasing uncertainties in future warming estimation. [ABSTRACT FROM AUTHOR]

Highlights • A method to measure nanocrystalline samples crystalline fraction fc is presented. • Superparamagnetic transition temperature Ttr is used to determine fc. • The Ttr crystalline fraction dependency is modelled. • The intergrain dipolar coupling an interphase exchange coupling are considered. • Experimental measurement have beeb carried out and are presented. [ABSTRACT FROM AUTHOR]

Abstract: Atmospheric cloud radiative effects (ACRE) narrow the Intertropical Convergence Zones (ITCZs) in climate models. Some studies have attributed this to the upper tropospheric heating by deep clouds. We report two types of idealized aquaplanet experiments, one where ACRE in specific altitude ranges is removed and another where the ACRE associated with clouds in specific altitude ranges is removed. Lower tropospheric heating due to upper tropospheric clouds in the deep tropics exerts the greatest impact on the ITCZ width and meridional overturning, even though the heating is weaker than in the upper troposphere. It is argued that this is because radiatively driven changes in the shallow circulation drive a feedback via net import of MSE and make the ITCZ more unstable in its core, thereby forcing the ITCZ to contract. The radiative effects of clouds in the subsiding subtropics are found to be of secondary importance in driving the necessary circulation changes. [ABSTRACT FROM AUTHOR]

This article focuses on the modeling of the hysteresis loop featured by Fe-Cu-Nb-Si-B nanocrystalline alloys with transverse induced anisotropy. The magnetization reversal process of a magnetic correlated volume (CV), characterized by the induced anisotropy Ku, and a deviation of the local easy magnetization direction featuring the effect of a local incoherent anisotropy Ki, is analyzed, taking account of magnetostatic interactions. Solving the equations shows that considering a unique typical kind of CV does not enable accounting for both the domain pattern and the coercivity. Actually, the classical majority CVs obeying the random anisotropy model explains well the domain pattern but considering another kind of CVs, minority, mingled with classical ones, featuring a magnitude of Ki comparable to Ku, is necessary to account for coercivity. The model has been successfully compared with experimental data. [ABSTRACT FROM AUTHOR]

This paper focuses on the modeling of the hysteresis of Fe–Cu–Nb–Si–B nanocrystalline alloys with transverse induced anisotropy Ku based on the behavior of a correlated volume (CV). Only coherent rotation mechanism was considered, given the chosen value of Ku . The formulations account for Ku , the incoherent anisotropy Ki , and the magnetostatic energy. The solving of the equations shows the existence of two kinds of CVs: the first one is responsible for the domain pattern, while the other causes the coercivity. The model has been compared with experimental data, and improved by considering the existence of a minority of CVs featuring strong incoherent anisotropy, causing the coercivity, mingled with classical CVs obeying the random anisotropy model. [ABSTRACT FROM AUTHOR]

The effect of high external magnetic field (up to 7 T) on soft magnetic properties in nanocrystalline Fe 74.1 Si 15.7 Nb 3.1 B 6.1 Cu 1 Nanophy ® cores has been investigated. The as-quenched amorphous ribbons were nanocrystallized by annealing between 540 and 620 °C in transverse magnetic field. By varying annealing field from 0 to 7 T, induced anisotropy ranging from as low as 4 J/m 3 to as high as 41 J/m 3 is obtained. It is responsible for an increase in the cut-off frequency up to 300 kHz when the material is submitted to dynamic magnetic excitations. A minimum coercivity of 0.74 A/m is observed in the core annealed in 1 T associated to low losses. The relative permeability decreases on increasing the annealing field intensity with a minimum value of 13,654 at 7 T. Such permeability level opens the way to new applications of the Nanophy ® alloys. [ABSTRACT FROM AUTHOR]

Cloud radiative cooling at the top of stratocumulus is crucial to power turbulence in the well-mixed, stratocumulus-topped atmospheric boundary layer (ABL). The present work uses a large-eddy simulation model to understand how finely the spatial structure of the cloud radiative effect (CRE) has to be represented in order to sustain a stratocumulus-topped ABL in equilibrium. We first explore whether the vertical structure of the CRE can be simplified, and it appears that the cloud radiative cooling in the upper part of the cloud is essential to the existence of the equilibrium stratocumulus, and that the CRE has to be represented in some detail around the cloud top to sustain this equilibrium. Second, we investigate how the horizontal heterogeneities of CRE impact the stratocumulus equilibrium. Horizontal homogenization of the radiative cooling has a small thinning impact on the stratocumulus-topped ABL. Because of the nonlinear dependence of the cloud radiative cooling on the liquid water path (LWP), computing the CRE from the mean liquid water profile overestimates the vertically integrated CRE and yields an unstable, ever-growing ABL. Assuming a simple sub-domain distribution of LWP and adjusting the cloud radiative cooling accordingly is sufficient to correct for this overestimation and sustain a stratocumulus equilibrium. Finally, we check that vertical and horizontal simplifications of the CRE are compatible, which opens perspectives for its representation in bulk models and larger-scale models. [ABSTRACT FROM AUTHOR]

The present work investigates the equilibrium of the atmospheric boundary layer (ABL) over the ocean using a large-eddy simulation model, with different lower-boundary sea-surface temperatures (SSTs) and different initial conditions. For low SSTs, one of two equilibria is reached depending on the initial conditions. One equilibrium is characterized by a deep, stratocumulus-capped ABL, while the other is a thin, cloud-free ABL. Cloud radiative cooling at the top of the stratocumulus is crucial to the existence of the stratocumulus equilibrium. If the SST is increased, the stratocumulus equilibrium becomes deeper and the cloud radiative effect reaches a maximum before decreasing due to buoyancy reversal and decoupling. This decrease of cloud radiative effect with SST eventually suppresses the stratocumulus equilibrium at higher SSTs-all initial conditions then lead to the cloud-free equilibrium. If the SST is increased further, the cloud-free equilibrium becomes a deeper, shallow convective equilibrium with cumuli in the upper part of the ABL. This shallow convective ABL is deepened by the cloud radiative effect. Our results suggest that the transition from stratocumulus decks in the eastern subtropical oceans to the trade-wind shallow convective regions is essentially a transition from one basin of attraction, which disappears, to another. [ABSTRACT FROM AUTHOR]

In this study we investigate the role of the mechanisms at play in the magnitude of the land-sea warming contrast and its intermodel spread in the fifth coupled models intercomparison project (CMIP5) simulations. In this aim, an energy-balance model (EBM), with one box representing the land area and two other boxes the near-surface and the deep ocean, is developed. In particular, a simple parameterization of the horizontal energy transport (HET) change between these two regions is proposed. The EBM is shown to capture the variation of the land and the ocean temperature responses and of the land-sea warming ratio in different idealized climate change experiments. By using this framework, we first show that the land-sea warming contrast is explained by the asymmetry in the strength of the HET between the land and ocean and not by land-sea differences in radiative feedbacks. Then we use a method of analysis of variance to infer the contributors to the intermodel spread in the land-sea warming ratio of climate models participating to CMIP5. The main contributor is found to be the HET with a contribution of about 70 %. Finally, our results suggest that the asymmetric character of the HET dependency to the land and the ocean temperature responses may be primarily explained by the land-sea differences in surface specific humidity change for a given temperature change. [ABSTRACT FROM AUTHOR]

This study provides a comprehensive global analysis of the climate radiative feedbacks and the adjusted radiative forcing for a CO increase perturbation in the CNRM-CM5 climate model using the partial radiative perturbations (PRP) method. Some methodological key points of the PRP are investigated, with a particular focus on the consideration of the effect of fast adjustments. First, the standard PRP method is applied by neglecting certain fast adjustments. The effect of the field decorrelation is highlighted by performing a PRP across two different periods of a control experiment and by analyzing second-order terms. Sensitivity tests to the field substitution frequency, the sampling period and the perturbed experiment used are performed. The impact of the definition of the top of the climate system (top-of-the-atmosphere or tropopause) in the feedback estimate is also discussed. Secondly, the fast adjustment processes are taken into account by combining the PRP framework with the method of linear regression of the partial net radiative flux change against the mean surface air temperature change using a step forcing experiment. This method allows us to quantify the contribution of the different constituents to the forcing adjustment and to improve the estimation of the radiative feedbacks. It is shown that such decomposition allows the retrieval of the adjusted radiative forcing, the radiative feedbacks and the climate sensitivity as estimated with the linear regression method with a high level of accuracy, validating the partial decomposition. [ABSTRACT FROM AUTHOR]

A two-pattern decomposition of the mean surface air temperature response to an increase of CO2 is assessed. This decomposition is based on a two-layer global energy-balance model and the hypothesis of separability in space and time. It is shown that this decomposition allows the regional transient warming of a given atmosphere-ocean general circulation model to be well represented. The pattern decomposition is applied to 16 CMIP5 climate models and each of the two retrieved patterns - the equilibrium pattern and the pattern associated with the deep-ocean heat uptake - is described and discussed. [ABSTRACT FROM AUTHOR]

An overview of radiative climate feedbacks and ocean heat uptake efficiency diagnosed from idealized transient climate change experiments of 14 CMIP5 models is presented. Feedbacks explain about two times more variance in transient climate response across the models than ocean heat uptake efficiency. Cloud feedbacks can clearly be identified as the main source of inter-model spread. Models with strong longwave feedbacks in the tropics feature substantial increases in cloud ice around the tropopause suggestive of changes in cloud-top heights. The lifting of the tropical tropopause goes together with a general weakening of the tropical circulation. Distinctive inter-model differences in cloud shortwave feedbacks occur in the subtropics including the equatorward flanks of the storm-tracks. Related cloud fraction changes are not confined to low clouds but comprise middle level clouds as well. A reduction in relative humidity through the lower and mid troposphere can be identified as being the main associated large-scale feature. Experiments with prescribed sea surface temperatures are analyzed in order to investigate whether the diagnosed feedbacks from the transient climate simulations contain a tropospheric adjustment component that is not conveyed through the surface temperature response. The strengths of the climate feedbacks computed from atmosphere-only experiments with prescribed increases in sea surface temperatures, but fixed CO 2 concentrations, are close to the ones derived from the transient experiment. Only the cloud shortwave feedback exhibits discernible differences which, however, can not unequivocally be attributed to tropospheric adjustment to CO 2. Although for some models a tropospheric adjustment component is present in the global mean shortwave cloud feedback, an analysis of spatial patterns does not lend support to the view that cloud feedbacks are dominated by their tropospheric adjustment part. Nevertheless, there is positive correlation between the strength of tropospheric adjustment processes and cloud feedbacks across different climate models. [ABSTRACT FROM AUTHOR]

In this paper, we present a novel rotating actuator based on the interaction of a permanent magnet with a magnetostrictive soft ribbon submitted to mechanical stress. The direction and magnitude of the stress generates a directional magnetic anisotropy (easy axis) in the soft ribbon. A nonzero angle between the polarizing magnet and the induced easy axis results in a torque between the two: hence the magnet being free to rotate aligns itself with the easy axis. A demonstrator of this principle was made using a Nd–Fe–B magnet above a disk cut from an iron-based amorphous ribbon glued between two unidirectional piezoelectric actuators. The analytical model takes into account the magnetic domains and assumes a magnetization mechanism of both coherent rotation and domain-wall displacement, with a uniaxial anisotropy induced by the applied stress. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to evaluate the feasibility, safety, and potential role of gadoterate meglumine (Gd-DOTA) as a contrast agent for upper extremity venography before the creation of an arteriovenous fistula (AVF) for nondialyzed renal insufficiency patients.Methods: Over a 16-month period, 50 venographies were performed on end-stage renal insufficiency patients, using Gd-DOTA as a contrast agent on a high-resolution digital subtraction angiography system. Three sequences were performed on forearm, arm, and chest at 3 mL/sec for a total of 35 mL of Gd-DOTA. Examinations were reviewed by two radiologists for diagnostic and opacification quality. Tolerance was evaluated on the evolution of serum creatinine levels and occurrence of pain during injection.Results: Good interobserver correlation was obtained in evaluating the feasibility of AVF creation by vein segment (0.64 < kappa < 0.88) and in relationship to opacification quality (0.62 to 0.87). No deterioration in renal function (creatinine level before and after) or pain was observed. Twenty-six patients underwent surgical creation of brachiobasilic (N = 8), brachiocephalic (N = 8), radiocephalic (N = 8), and cubitocephalic (N = 1) fistulas or insertion of a polytetrafluoroethylene (PTFE) graft (N = 1). Seventeen were awaiting AVF or were on peritoneal dialysis. Two died before surgery for reasons unconnected with the venography.Conclusions: Venography with Gd-DOTA is an effective and safe technique in planning AVFs for renal insufficiency patients. [ABSTRACT FROM AUTHOR]

Background: Coverage of HIV testing remains sub-optimal in West Africa. Between 2019 and 2022, the ATLAS program distributed ~400 000 oral HIV self-tests (HIVST) in Côte d'Ivoire, Mali, and Senegal, prioritising female sex workers (FSW) and men having sex with men (MSM), and relying on secondary redistribution of HIVST to partners, peers and clients to reach individuals not tested through conventional testing. This study assesses the proportion of first-time testers among HIVST users and the associated factors. Methods: A phone-based survey was implemented among HIVST users recruited using dedicated leaflets inviting them to anonymously call a free phone number. We collected socio-demographics, sexual behaviours, HIV testing history, HIVST use, and satisfaction with HIVST. We reported the proportion of first-time testers and computed associated factors using logistic regression. Results: Between March and June 2021, 2 615 participants were recruited for 50 940 distributed HIVST (participation rate: 5.1%). Among participants, 30% received their HIVST kit through secondary distribution (from a friend, sexual partner, family member, or colleague). The proportion who had never tested for HIV before HIVST (first-time testers) was 41%. The main factors associated with being a first-time tester were sex, age group, education level, condom use, and secondary distribution. A higher proportion was observed among those aged 24 years or less (55% vs 32% for 25–34, aOR: 0.37 [95%CI: 0.30–0.44], and 26% for 35 years or more, aOR: 0.28 [0.21–0.37]); those less educated (48% for none/primary education vs 45% for secondary education, aOR: 0.60 [0.47–0.77], and 29% for higher education, aOR: 0.33 [0.25–0.44]). A lower proportion was observed among women (37% vs 43%, aOR: 0.49 [0.40–0.60]); those reporting always using a condom over the last year (36% vs 51% for those reporting never using them, aOR: 2.02 [1.59–2.56]); and those who received their HISVST kit through primary distribution (39% vs 46% for secondary distribution, aOR: 1.32 [1.08–1.60]). Conclusion: ATLAS HIVST strategy, including secondary distribution, successfully reached a significant proportion of first-time testers. HIVST has the potential to reach underserved populations and contribute to the expansion of HIV testing services in West Africa. [ABSTRACT FROM AUTHOR]

Convection is often assumed to be controlled by the simultaneous environmental fields. But to what extent does it also remember its past behavior? This study proposes a new framework in which the memory of previous convective-scale behavior, "microstate memory," is distinguished from macrostate memory, and conducts numerical experiments to reveal these memory types. A suite of idealized, cloud-resolving radiative–convective equilibrium simulations in a 200-km square domain is performed with the Weather Research and Forecasting (WRF) Model. Three deep convective cases are analyzed: unorganized, organized by low-level wind shear, and self-aggregated. The systematic responses to sudden horizontal homogenization of various fields, in various atmospheric layers, designed to eliminate their specific microstructure, are compared in terms of precipitation change and time of recovery to equilibrium. Results imply a substantial role for microstate memory. Across organization types, microstructure in water vapor and temperature has a larger and longer-lasting effect on convection than in winds or hydrometeors. Microstructure in the subcloud layer or the shallow cloud layer has more impact than in the free troposphere. The recovery time scale dramatically increases from unorganized (2–3 h) to organized cases (24 h or more). Longer-time-scale adjustments also occur and appear to involve both small-scale structures and domain-mean fields. These results indicate that most convective microstate memory is stored in low-level thermodynamic structures, potentially involving cold pools and hot thermals. This memory appears strongly enhanced by convective organization. Implications of these results for parameterizing convection are discussed. [ABSTRACT FROM AUTHOR]

A warming climate is expected to intensify extreme precipitation, and climate models project a general intensification of annual extreme precipitation in most regions of the globe throughout the twenty-first century. We investigate the robustness of this future intensification over land across different models, regions, and seasons and evaluate the role of model interdependencies in the CMIP5 ensemble. Strong similarities in extreme precipitation changes are found between models that share atmospheric physics, turning an ensemble of 27 models into around 14 projections. We find that future annual extreme precipitation intensity increases in the majority of models and in the majority of land grid cells, from the driest to the wettest regions, as defined by each model’s precipitation climatology. The intermodel spread is generally larger over wet than over dry regions, smaller in the dry season compared to the wet season and at the annual scale, and largely reduced in extratropical compared to tropical regions and at the global scale. For each model, the future increase in annual and seasonal maximum daily precipitation amounts exceeds the range of simulated internal variability in the majority of land grid cells. At both annual and seasonal scales, however, there are a few regions where the change is still within the background climate noise, but their size and location differ between models. In extratropical regions, the signal-to-noise ratio of projected changes in extreme precipitation is particularly robust across models because of a similar change and background climate noise, whereas projected changes are less robust in the tropics. [ABSTRACT FROM AUTHOR]

Introduction: HIV epidemics in Western and Central Africa (WCA) remain concentrated among key populations, who are often unaware of their status. HIV self-testing (HIVST) and its secondary distribution among key populations, and their partners and relatives, could reduce gaps in diagnosis coverage. We aimed to document and understand secondary HIVST distribution practices by men who have sex with men (MSM), female sex workers (FSW), people who use drugs (PWUD); and the use of HIVST by their networks in Côte d'Ivoire, Mali, and Senegal. Methods: A qualitative study was conducted in 2021 involving (a) face-to-face interviews with MSM, FSW, and PWUD who received HIVST kits from peer educators (primary users) and (b) telephone interviews with people who received kits from primary contacts (secondary users). These individual interviews were audio-recorded, transcribed, and coded using Dedoose software. Thematic analysis was performed. Results: A total of 89 participants, including 65 primary users and 24 secondary users were interviewed. Results showed that HIVST were effectively redistributed through peers and key populations networks. The main reported motivations for HIVST distribution included allowing others to access testing and protecting oneself by verifying the status of partners/clients. The main barrier to distribution was the fear of sexual partners' reactions. Findings suggest that members of key populations raised awareness of HIVST and referred those in need of HIVST to peer educators. One FSW reported physical abuse. Secondary users generally completed HIVST within two days of receiving the kit. The test was used half the times in the physical presence of another person, partly for psychological support need. Users who reported a reactive test sought confirmatory testing and were linked to care. Some participants mentioned difficulties in collecting the biological sample (2 participants) and interpreting the result (4 participants). Conclusion: The redistribution of HIVST was common among key populations, with minor negative attitudes. Users encountered few difficulties using the kits. Reactive test cases were generally confirmed. These secondary distribution practices support the deployment of HIVST to key populations, their partners, and other relatives. In similar WCA countries, members of key populations can assist in the distribution of HIVST, contributing to closing HIV diagnosis gaps. [ABSTRACT FROM AUTHOR]

Paleoclimatic proxies indicate that significant summertime rainfall reached the Sahara region during the mid-Holocene, presumably in response to stronger summertime heating in the Northern Hemisphere. Climate models generally do not replicate the enhanced precipitation. As a step toward understanding the response and possible role of model errors, a series of idealized experiments were conducted with the Community Earth System Model in which local atmospheric heat sources of increasing magnitude were applied in the boundary layer over the Sahel and Sahara. In response to this local heating, the cold and moist southwesterly monsoon inflow encroaches farther northward. A source strength of roughly 1Kday-1 produces responses similar to those in a simulation with mid-Holocene orbital forcing imposed globally, while that of 1.5Kday-1 produces a precipitation response similar to that from paleoproxies. The precipitation increases nonlinearly, with a jump at heating of around 1Kday-1, even though the low-level monsoon inflow increases linearly. Competition at low-to-middle levels between drying by a shallow return flow just above the boundary layer and moistening by vertical advection within the layer affects convection and determines the northward extension of precipitation. When the heating becomes 1.5Kday-1, the boundary layer flow encroaches sufficiently northward to weaken the shallow return flow, further aiding precipitation. This novel nonlinear mechanism operates without biogeophysical feedbacks, and suggests that poor representation of the local thermodynamic processes may hamper a model's ability to simulate dynamical feedbacks and hence the strength and poleward extension of monsoon rains under forcings like those during the mid-Holocene. [ABSTRACT FROM AUTHOR]

Ocean heat content (OHC) is one of the most relevant metrics tracking the current global heating. Therefore, simulated OHC time series are a cornerstone for assessing the scientific performance of Earth system models and global climate models. Here we present a detailed analysis of OHC change in simulations of the historical climate (1850–2014) performed with two pairs of CMIP6 models: U.K. Earth System Model 1 (UKESM1.0) and HadGEM3-GC3.1-LL, and CNRM-ESM2-1 and CNRM-CM6-1. The small number of models enables us to analyze OHC change globally and for individual ocean basins, making use of a novel ensemble of observational products. For the top 700 m of the global ocean, the two CNRM models reproduce the observed OHC change since the 1960s closely. The two U.K. models (UKESM1.0-LL and HadGEM3-GC3.1-LL) compensate a lack of warming in the 0–700 m layer in the 1970s and 1980s with warming below 2000 m. The observed warming between 700 and 2000 m is substantially underestimated by all models. An increased relevance for ocean heat uptake in the Atlantic after 1991—suggested by observations—is picked up by the U.K. models but less so by the CNRM models, probably related to an AMOC strengthening in the U.K. models. The regional ocean heat uptake characteristics differ even though all four models share the same ocean component (NEMO ORCA1). Differences in the simulated global, full-depth OHC time series can be attributed to differences in the model's total effective radiative forcing. [ABSTRACT FROM AUTHOR]

Midlatitude weather is largely governed by bands of strong westerly winds known as the midlatitude jets, but what controls the jet properties, particularly their latitudes, remains poorly understood. Climate models show a spread of about 10° in their simulated present-day latitude of the Southern Hemisphere (SH) jet, and a related spread in its predicted poleward shift under global warming. We find that models with more poleward jets simulate more low-level moisture, a warmer upper troposphere, and different precipitation patterns than those with equatorward jets, potentially implicating intermodel differences in moist convection and microphysics. Accordingly, a suite of atmospheric model runs is performed where the deep or shallow convective parameterizations are individually turned off either globally or in specific latitude bands. These experiments suggest that models that produce more shallow convection in the midlatitudes tend to position the jet relatively poleward in SH summer, whereas those that favor deep convection tend to position it equatorward. This accounts for a spread 60% as large as that of the AMIP ensemble during the austral summer. Our results suggest that, in the boreal summer, similar biases appear in the Northern Hemisphere. The presence of shallow convection in the Northern Hemisphere midlatitudes reduces SH jet shift in a warmer climate in accordance to the correlation between jet positions and shift seen in this season. These results can help explain intermodel differences in the position and shift of the jet, and point to an unexpected role for atmospheric moist convection in the midlatitude circulation. [ABSTRACT FROM AUTHOR]

Abstract: In the paper, the development of a multiphysics model for the transient analysis of non-moderated Molten Salt Reactors is discussed. Particular attention is devoted to the description of the adopted time integration and physics coupling strategies. The proposed model features the adoption of an implicit Runge–Kutta scheme and the coupling among neutron diffusion, Reynolds-Averaged Navier–Stokes equations for mass and momentum conservation, and energy and delayed neutron precursor balance equations, in order to accurately catch thermal feedbacks on neutronics. The solver is aimed at performing fast-running simulations of the full-core three-dimensional Molten Salt Fast Reactor geometry. The neutronics modelling is assessed against Monte Carlo simulations and the results of a simplified case study are compared to those from multiphysics tools previously developed. As an example of the capability of the model, an unprotected MSFR single pump failure accidental scenario is simulated and discussed. The main purpose of the present model is to serve as fast-running computational tool in the phase of design optimization of fuel loop components. More in general, it is of valuable help in the study of reactor physics of circulating-fuel systems. [Copyright &y& Elsevier]

Background: Due to the discreet and private nature of HIV self-testing (HIVST), it is particularly challenging to monitor and assess the impacts of this testing strategy. To overcome this challenge, we conducted a study in Côte d'Ivoire to characterize the profile of end users of HIVST kits distributed through the ATLAS project (AutoTest VIH, Libre d'Accéder à la connaissance de son Statut). Feasibility was assessed using a pilot phone-based survey. Methods: The ATLAS project aims to distribute 221300 HIVST kits in Côte d'Ivoire from 2019 to 2021 through both primary (e.g., direct distribution to primary users) and secondary distribution (e.g., for partner testing). The pilot survey used a passive recruitment strategy—whereby participants voluntarily called a toll-free survey phone number—to enrol participants. The survey was promoted through a sticker on the HIVST instruction leaflet and hotline invitations and informal promotion by HIVST kit-dispensing agents. Importantly, participation was not financially incentivized, even though surveys focussed on key populations usually use incentives in this context. Results: After a 7-month period in which 25,000 HIVST kits were distributed, only 42 questionnaires were completed. Nevertheless, the survey collected data from users receiving HIVST kits via both primary and secondary distribution (69% and 31%, respectively). Conclusion: This paper provides guidance on how to improve the design of future surveys of this type. It discusses the need to financial incentivize participation, to reorganize the questionnaire, the importance of better informing and training stakeholders involved in the distribution of HIVST, and the use of flyers to increase the enrolment of users reached through secondary distribution. [ABSTRACT FROM AUTHOR]

Recent large-eddy simulation (LES) studies of the impact of aerosol on the dynamics of nocturnal marine stratocumulus revealed that, depending on the large-scale forcings, an aerosol-induced increase of the droplet concentration can lead to either an increase or a decrease of the liquid water path, hence contrasting with the cloud thickening that is expected from a reduction of the precipitation efficiency. In this study, the aerosol impacts on cloud microphysics are examined in the context of the boundary-layer diurnal cycle using 36-h LES simulations of pristine and polluted clouds. These simulations corroborate previous findings that during nighttime aerosol-induced liquid water path changes are sensitive to the large-scale forcings via enhancement of cloud-top entrainment such that, ultimately, the liquid water path may be reduced when the free-tropospheric-entrained air is drier. During the day, however, enhanced entrainment, inhibition of drizzle evaporation below cloud base, and reduced sensible heat flux from the surface lead to a more pronounced decoupling of the boundary layer, which significantly amplifies the liquid water path reduction of the polluted clouds. At night the sign of the liquid water path difference between pristine and polluted clouds depends upon large-scale forcings, while during the day the liquid water path of polluted clouds is always smaller than the one of the pristine clouds. Suggestions are made on how observational studies could be designed for validation of these simulations. [ABSTRACT FROM AUTHOR]

In this paper we present the development of a rotating sample magnetometer (RSM) for real time differential magnetic moment measurement. The high accuracy and simplicity of the described apparatus allow reliable and fast magnetic characterization of samples with small magnetic moment. This performances (about 10-10 A m2 with our prototype), associated with the low cost of the apparatus, should make it a very promising tool for thin magnetic film characterization. [ABSTRACT FROM AUTHOR]

• Investigation of the memory effect underlying the establishment of induced anisotropy. • Experiment method to boost the field applied to the treated cores during annealing. • Polarization during the annealing have been investigated through simulation process. We study the relation between the induced anisotropy obtained on nanocrystalline Fe 73.0 Cu 1.1 Nb 3.1 Si 15.7 B 7.1 toroidal cores crystallized under transverse field at 570 °C, and the polarization J c of nanograins. To do this, an original disposition is used, mixing treated cores with cores made of electrotechnical SiFe alloy, featuring same geometry, using the interfacial magnetic charges to increase the field in treated cores. The field supplied by the coil being μ 0 H a = 33 m T , playing on the proportion between treated and SiFe cores, effective field ranging between 33 m T and 230 m T were obtained inside treated cores. As a result, the induced anisotropy at the scale of the alloys at the end of crystallization range from K u = 12 J / m 3 to K u = 20 J / m 3. To simulate the evolution of J c during the crystallization process, the configuration of treated and SiFe cores in the sample holder was implemented in Altair FluxT FEM simulation environment with the dedicated polarization laws. Dealing with treated cores, the law J cor (H) at the scale of the core reflects the law J c H featured by nanograins during the crystallization process. J c H was modelized as a function of the crystallized fraction f c. The relation between the simulated J c and the experimental final values of K u / f c (i.e. the anisotropy in nanograins) was then studied. This was done considering the polarization 〈 J c 〉 averaged on the entire crystallization process, wondering about a possible memory effect. [ABSTRACT FROM AUTHOR]

The methods to quantify equilibrium climate sensitivity are still debated. We collect millennial‐length simulations of coupled climate models and show that the global mean equilibrium warming is higher than those obtained using extrapolation methods from shorter simulations. Specifically, 27 simulations with 15 climate models forced with a range of CO2 concentrations show a median 17% larger equilibrium warming than estimated from the first 150 years of the simulations. The spatial patterns of radiative feedbacks change continuously, in most regions reducing their tendency to stabilizing the climate. In the equatorial Pacific, however, feedbacks become more stabilizing with time. The global feedback evolution is initially dominated by the tropics, with eventual substantial contributions from the mid‐latitudes. Time‐dependent feedbacks underscore the need of a measure of climate sensitivity that accounts for the degree of equilibration, so that models, observations, and paleo proxies can be adequately compared and aggregated to estimate future warming. Key Points: Twenty‐seven simulations of 15 general circulation models are integrated to near equilibriumAll models simulate a higher equilibrium warming than predicted by using extrapolation methodsTropics and middle latitudes dominate the change of the feedback parameter on different time scales [ABSTRACT FROM AUTHOR]

The methods to quantify equilibrium climate sensitivity are still debated. We collect millennial‐length simulations of coupled climate models and show that the global mean equilibrium warming is higher than those obtained using extrapolation methods from shorter simulations. Specifically, 27 simulations with 15 climate models forced with a range of CO2 concentrations show a median 17% larger equilibrium warming than estimated from the first 150 years of the simulations. The spatial patterns of radiative feedbacks change continuously, in most regions reducing their tendency to stabilizing the climate. In the equatorial Pacific, however, feedbacks become more stabilizing with time. The global feedback evolution is initially dominated by the tropics, with eventual substantial contributions from the mid‐latitudes. Time‐dependent feedbacks underscore the need of a measure of climate sensitivity that accounts for the degree of equilibration, so that models, observations, and paleo proxies can be adequately compared and aggregated to estimate future warming. Key Points: Twenty‐seven simulations of 15 general circulation models are integrated to near equilibriumAll models simulate a higher equilibrium warming than predicted by using extrapolation methodsTropics and middle latitudes dominate the change of the feedback parameter on different time scales [ABSTRACT FROM AUTHOR]

Understanding the mid-latitude atmospheric circulation response to CO 2 forcing is challenging and complex due to the strong internal variability and the multiple potential CO 2 -induced effects. While a significant poleward shift of the jet is projected in summer, changes remain uncertain in winter. In this study, we investigate the boreal winter extratropical jet response to an abrupt quadrupling of atmospheric CO 2 in the CMIP6-generation global climate model CNRM-CM6-1. First, we show that the model performs better than the former generation CNRM-CM5 model in representing the atmospheric dynamics in the northern extratropics. Then, when atmospheric CO 2 is quadrupled, CNRM-CM6-1 exhibits a strengthening and upward shift of the jet. A poleward shift is identified and robust in the Pacific in boreal winter. In the Atlantic, the jet response rather exhibits a squeezing, especially at the eastern part of the basin. It is found that changes are more robust across the Northern Hemisphere in early-winter than in late-winter season. Finally, the circulation response is broken down into individual contributions of various drivers. The uniform global mean component of the SST warming is found to explain most of the total atmospheric response to a quadrupling of CO 2 , with relatively smaller contributions from faster CO 2 effects, the SST pattern change and the Arctic sea ice decline. The cloud radiative effect contribution is also assessed and found to be rather weak in the CNRM-CM6-1 model. This study highlights that long experiments are required to isolate the wintertime circulation response from the internal variability, and that idealized experimental setups are helpful to disentangle the physical drivers. [ABSTRACT FROM AUTHOR]

We present a model intercomparison project, LongRunMIP, the first collection of millennial-length (1,000+ years) simulations of complex coupled climate models with a representation of ocean, atmosphere, sea ice, and land surface, and their interactions. Standard model simulations are generally only a few hundred years long. However, modeling the long-term equilibration in response to radiative forcing perturbation is important for understanding many climate phenomena, such as the evolution of ocean circulation, time- and temperature-dependent feedbacks, and the differentiation of forced signal and internal variability. The aim of LongRunMIP is to facilitate research into these questions by serving as an archive for simulations that capture as much of this equilibration as possible. The only requirement to participate in LongRunMIP is to contribute a simulation with elevated, constant CO2 forcing that lasts at least 1,000 years. LongRunMIP is an MIP of opportunity in that the simulations were mostly performed prior to the conception of the archive without an agreed-upon set of experiments. For most models, the archive contains a preindustrial control simulation and simulations with an idealized (typically abrupt) CO2 forcing. We collect 2D surface and top-of-atmosphere fields and 3D ocean temperature and salinity fields. Here, we document the collection of simulations and discuss initial results, including the evolution of surface and deep ocean temperature and cloud radiative effects. As of October 2019, the collection includes 50 simulations of 15 models by 10 modeling centers. The data of LongRunMIP are publicly available. We encourage submissions of more simulations in the future. [ABSTRACT FROM AUTHOR]

This study introduces CNRM‐ESM2‐1, the Earth system (ES) model of second generation developed by CNRM‐CERFACS for the sixth phase of the Coupled Model Intercomparison Project (CMIP6). CNRM‐ESM2‐1 offers a higher model complexity than the Atmosphere‐Ocean General Circulation Model CNRM‐CM6‐1 by adding interactive ES components such as carbon cycle, aerosols, and atmospheric chemistry. As both models share the same code, physical parameterizations, and grid resolution, they offer a fully traceable framework to investigate how far the represented ES processes impact the model performance over present‐day, response to external forcing and future climate projections. Using a large variety of CMIP6 experiments, we show that represented ES processes impact more prominently the model response to external forcing than the model performance over present‐day. Both models display comparable performance at replicating modern observations although the mean climate of CNRM‐ESM2‐1 is slightly warmer than that of CNRM‐CM6‐1. This difference arises from land cover‐aerosol interactions where the use of different soil vegetation distributions between both models impacts the rate of dust emissions. This interaction results in a smaller aerosol burden in CNRM‐ESM2‐1 than in CNRM‐CM6‐1, leading to a different surface radiative budget and climate. Greater differences are found when comparing the model response to external forcing and future climate projections. Represented ES processes damp future warming by up to 10% in CNRM‐ESM2‐1 with respect to CNRM‐CM6‐1. The representation of land vegetation and the CO2‐water‐stomatal feedback between both models explain about 60% of this difference. The remainder is driven by other ES feedbacks such as the natural aerosol feedback. Key Points: This study introduces CNRM‐ESM2‐1 and describes its set‐up for CMIP6Represented Earth system processes further impact the model response to external forcing than the model performance over present‐dayRepresented Earth system processes damp future warming by up to 10% [ABSTRACT FROM AUTHOR]

A telephone survey among self-test end users in Côte d'Ivoire, Mali, and Senegal Correction: Can HIV self-testing reach first-time testers? B BMC Infectious Diseases (2023) 22:972 b https://doi.org/10.1186/s12879-023-08626-w The original publication of this article contained an incorrect author name. [Extracted from the article]

In this paper, the magnetic losses of a supply current sensor dedicated to circuit breakers are investigated. Measurements were performed using an accurate calorimeter covering a measurement range of [1 mW; 10 W]. Several frequencies and voltages were tested. A model of the sensor's core material (NO SiFe sheet M250-50A) was built with the Loss Surface (LS) dynamic hysteresis model and implemented in a 3D FEM computation tool. The sensor was simulated and iron losses were computed. Comparison between experiments and simulation shows a high concordance that leads to conclude about the reliability of the LS model. [ABSTRACT FROM AUTHOR]

The article investigates the impact of aerosol composition on the estimation of the downwelling surface shortwave flux (DSSF). This initiative forms part of the efforts to improve the DSSF distributed by the Land Surface Analysis Satellite Application Facility (LSA-SAF). This operational product assumes invariant aerosol properties under clear sky conditions, which can be inaccurate for some regions of the world. This is the case of West Africa, where aerosol activity is not only highly variable due to frequent dust storms but also rich because of the coexistence of different aerosol species. This study was carried out over the West African stations of Dakar and Niamey, which represent different aerosol scenarios. Several dates during the dry season of 2006 were selected and classified into four different day types according to aerosol activity: standard, clean, mixture and dusty days. The diurnal evolution of DSSF and its direct and diffuse components were estimated for the selected dates by the current LSA-SAF algorithm and two other approaches using aerosol measurements from the Aerosol Robotic Network (AERONET) as input. The first alternative approach took the diurnal evolution of the total aerosol optical depth (AOD) into account, assuming a default desert aerosol type. Experiments with this method showed a significant improvement in the estimated DSSF compared to the current LSA-SAF algorithm. For example, root mean square error (RMSE) improved from 170 W/m2 to 50 W/m2 for dusty days in Dakar and from 73 W/m2 to 21 W/m2 for mixture days in Niamey. This improvement resulted from the consideration of a time-varying AOD, which accounted for the rapidly changing aerosol load for these two day types. The second alternative approach tested included consideration of the diurnal variation of the aerosol load and composition. Again, this was done using AERONET data on the fine and coarse aerosol modes, which may be associated with different sized dust particles, sea salt, or soot from biomass burning (depending on the date). This enhanced consideration of the aerosol composition greatly improved the estimation of the diffuse component of the DSSF, further reducing the RMSE during mixture days from 50 W/m2 to less than 10 W/m2. This improvement mainly came from consideration of the right scattering properties of the aerosol particles, which may be significantly different for each aerosol type. [ABSTRACT FROM AUTHOR]

Highlights: [•] Calculation of effective delayed neutron fraction in circulating-fuel reactors. [•] Extension of the Monte Carlo SERPENT-2 code for delayed neutron precursor tracking. [•] Forward and adjoint multi-group diffusion eigenvalue problems in OpenFOAM. [•] Analytical approach for β eff calculation in simple geometries and flow conditions. [•] Good agreement among the three proposed approaches in the MSFR test-case. [ABSTRACT FROM AUTHOR]

Usually niobium is added in ferritic stainless steels to avoid chromium carbides precipitation and then to improve corrosion resistance and to avoid embrittlemet. This study shows that a low Nb stabilization makes recrystallization nucleation much faster and prevents incomplete recrystallization. A qualitative interpretation, based on interaction with precipitates, is proposed and explains the main features of the softening kinetics as well as the microstructures obtained. Above a specific magnetizing frequency, the deformed state led to smaller losses than the recrystallized state. These results are believed to be attributed to a grain size effect. This leads to soft magnetic properties that makes 17%CrNb ferritic stainless steels a very interesting solution for the market of electromagnetic injection. Improving response-time of fuel injection valves is a great challenge for automotive industry in order to enhance car engine efficiency and to limit noxious gas emission. [ABSTRACT FROM AUTHOR]