We study the many-body localization (MBL) properties of the Heisenberg XXZ spin-$\frac 12$ chain in a random magnetic field. We prove that the system exhibits localization in any given energy interval at the bottom of the spectrum in a nontrivial region of the parameter space. This region, which includes weak interaction and strong disorder regimes, is independent of the size of the system and depends only on the energy interval. Our approach is based on the reformulation of the localization problem as an expression of quasi-locality for functions of the random many-body XXZ Hamiltonian. This allows us to extend the fractional moment method for proving localization, previously derived in a single-particle localization context, to the many-body setting.

The theory and practice of what has come to be called “deliberative democracy” have been revived for the modern era with a focus on deliberative microcosms selected through random sampling or “sortition.” But might it be possible to spread some of the benefits of deliberation beyond mini-publics to the broader society? Can technology assist with scaling an organized deliberative process? In particular, would those who experience such a process become more deliberative voters? Would their considered judgments from deliberation influence their voting? We draw on a larger than usual experiment with public deliberation and a one-year follow-up in the mid-term U.S. elections to suggest answers to these questions. It has implications for whether spreading an organized deliberative process could, in theory, be used to create more deliberative elections.

It is common wisdom that collisionless shocks become non-planar and non-stationary at sufficiently high Mach numbers. Whatever the shock structure, the upstream and downstream fluxes of the mass, momentum and energy should be equal. At low Mach numbers, these conservation laws are satisfied when the shock front is planar and stationary. When this becomes impossible, inhomogeneity and time dependence, presumably in the form of rippling, develop. In this study, we show that the shock structure changes as a kind of ‘phase transition’ when the Mach number is increased while other shock parameters are kept constant.

While dialectal variation is often investigated from a geographical angle, there exists substantial variation both within the community and individual. The aim of the present article is to investigate the extent to which spatial, occupational, and age-related factors are associated with the diversity of linguistic variants reported per informant at a given locality. Drawing on colloquial language data from the Atlas zur deutschen Alltagssprache ‘Atlas of Colloquial German,’ we found that informants from southeastern Germany and Austria reported familiarity with more variants. Moreover, we multifactorially operationalize occupational complexity, a variable that can capture the effects of different communicative, technical, and physical skills required in a job (via the Dictionary of Occupational Titles). Bayesian multilevel modeling revealed that informants in occupations involving physical precision work and communicative complexity reported less familiarity with variants, and that younger informants were familiar with a wider range of variants.

Adverse pressure gradient (APG) turbulent boundary layers (TBL) require an understanding of the details of the pressure gradient, or history effect, to characterize the associated variation of spatiotemporal turbulent statistics. The streamwise-varying mean pressure gradient is reflected in the streamwise developing mean flow field and thus resolvent analysis, which captures the amplification of the Navier–Stokes equations linearized about the turbulent mean, can be used to understand linear amplification in APG TBLs. In particular, by using a biglobal approach in which the amplification is characterized by a temporal frequency and spanwise wavenumber, the streamwise and wall-normal inhomogeneities of the APG TBL can be resolved and related to the APG history. The linear response is able to identify multiscale phenomena, identifying a near-wall peak with $\lambda _{z}^+\approx 100$ for zero pressure gradient TBLs and mild to moderate APG TBLs as well as large-scale modes whose amplification increases with APG strength and Reynolds number. It is shown that the monotonic growth in the turbulent statistics with increasing APG is reflected in the linear growth in the associated resolvent amplification. Collapse in the Reynolds stresses is obtained through an augmented hybrid velocity scale, which replaces the local APG strength measure in the hybrid velocity scale presented in Romero et al. (Intl J. Heat Fluid Flow, vol. 93, 2022, 108885) with a velocity that encapsulates the pressure gradient history. While this resolvent approach is applicable to any APG TBL, it is shown from a scaling analysis of the linearized Navier–Stokes equations that the linear growth observed in the resolvent amplification with the history effect is limited to near-equilibrium APG TBLs.

There is limited research into horse slaughter, particularly ante mortem welfare, and the effectiveness of captive-bolt gun (CBG) stunning, despite this being a widely used method worldwide. To address this evidence gap and explore associations between ante and post mortem factors, the welfare of 62 horses was assessed at a commercial Italian abattoir. Animal-based measures were used to identify stress-related behaviours and stunning effectiveness. A sub-sample (44%; 27/62) of heads were assessed for gross brain pathology. All animals in the study showed stress-related behaviours at all stages of the slaughter process. Additionally, 53% (33/62) of horses slipped in the stunning box, with poor floor surface condition and use of force associated with this. At least one sign of an ineffective stun was observed in 22% (14/62) of animals. Six animals were shot twice, with the application of a second shot significantly associated with a higher stress behaviour index score in the stunning box. Damage to critical brainstem structures was found in 85% (23/27) of heads that were assessed with gross pathology. An absence of damage to critical brainstem structures meant that animals were ten times more likely to show signs of ineffective stunning. These results highlight the risks to equine welfare throughout the slaughter process and suggest that mitigating ante mortem stress could improve stunning effectiveness, whilst CBG usage should be refined to ensure that critical brainstem structures are targeted.

Obesity is related to a wide variety of medical and psychological comorbidities which has short- and long-term effects on children’s mental health. One of the most significant ones is depression. Thus, the current study utilized a descriptive methodology to explore the differences in depressive symptoms among overweight, obese, and normal-weight Palestinian children and adolescents. Data was collected from 270 Palestinian children and adolescents, aged (9–16) years: 85 with normal weight, 95 with over-weight and 90 obese. Findings showed that participants who are over-weight or obese exhibited more depressive symptoms than those with a normal weight. These findings showed that Palestinian children and adolescents who are over-weight or obese do experience depression and thus interventions should take this into account. In particular, it seems that over-weight boys or adolescents need more direct help in losing weight while obese children and adolescents who feel more helpless about their weight need serious psychological interventions. it is critical to offer psychological treatment as part of any weight loss intervention program for children and adolescents. Especially as these adolescents’ families might encourage them to avoid seeking professional help and deal with the problem in the family.

For the pulse shaping system of the SG-II-up facility, we propose a U-shaped convolutional neural network that integrates multi-scale feature extraction capabilities, an attention mechanism and long short-term memory units, which effectively facilitates real-time denoising of diverse shaping pulses. We train the model using simulated datasets and evaluate it on both the simulated and experimental temporal waveforms. During the evaluation of simulated waveforms, we achieve high-precision denoising, resulting in great performance for temporal waveforms with frequency modulation-to-amplitude modulation conversion (FM-to-AM) exceeding 50%, exceedingly high contrast of over 300:1 and multi-step structures. The errors are less than 1% for both root mean square error and contrast, and there is a remarkable improvement in the signal-to-noise ratio by over 50%. During the evaluation of experimental waveforms, the model can obtain different denoised waveforms with contrast greater than 200:1. The stability of the model is verified using temporal waveforms with identical pulse widths and contrast, ensuring that while achieving smooth temporal profiles, the intricate details of the signals are preserved. The results demonstrate that the denoising model, trained utilizing the simulation dataset, is capable of efficiently processing complex temporal waveforms in real-time for experiments and mitigating the influence of electronic noise and FM-to-AM on the time–power curve.

The European Union receives thousands of unaccompanied irregular migrant minors every year, but little is known about their life experiences during the migration process. The aim of this study is to describe their experiences as minors when they arrived in Spain in small boats, which will help to understand their psychosocial and health needs. A descriptive qualitative study was undertaken. In-depth interviews were conducted with 18 unaccompanied irregular migrants (15 men and 3 women) from different African countries with a mean age of 20.05 years (SD = 2.77). Thematic analysis was used to analyse the data. Three main themes emerged such as (1) unaccompanied irregular migrant minors: risking it all for a better life; (2) redefining your identity as a means of adaptation and (3) obtaining legal status to avoid deportation. Unaccompanied migrant minors risk their lives on the migration journey, but do not always find better conditions in the destination country. The unaccompanied irregular migrant minors are forced to rebuild their lives at a high cost; they experience rejection from the host society and their culture of origin, which has a negative impact on their physical and psychological health over time.

Turbulent boundary layers on immersed objects can be significantly altered by the pressure gradients imposed by the flow outside the boundary layer. The interaction of turbulence and pressure gradients can lead to complex phenomena such as relaminarization, history effects and flow separation. The angular momentum integral (AMI) equation (Elnahhas & Johnson, J. Fluid Mech., vol. 940, 2022, A36) is extended and applied to high-fidelity simulation datasets of non-zero pressure gradient turbulent boundary layers. The AMI equation provides an exact mathematical equation for quantifying how turbulence, free-stream pressure gradients and other effects alter the skin friction coefficient relative to a baseline laminar boundary layer solution. The datasets explored include flat-plate boundary layers with nearly constant adverse pressure gradients, a boundary layer over the suction surface of a two-dimensional NACA 4412 airfoil and flow over a two-dimensional Gaussian bump. Application of the AMI equation to these datasets maps out the similarities and differences in how boundary layers interact with favourable and adverse pressure gradients in various scenarios. Further, the fractional contribution of the pressure gradient to skin friction attenuation in adverse-pressure-gradient boundary layers appears in the AMI equation as a new Clauser-like parameter with some advantages for understanding similarities and differences related to upstream history effects. The results highlight the applicability of the integral-based analysis to provide quantitative, interpretable assessments of complex boundary layer physics.

External seeded free-electron lasers (FELs) have exhibited substantial progress in diverse applications over the last decade. However, the frequency up-conversion efficiency in single-stage seeded FELs, particularly in high-gain harmonic generation (HGHG), remains constrained to a modest level. This limitation restricts its capability to conduct experiments within the ‘water window’. This paper presents a novel method for generating coherent X-ray FEL pulses in the water window region based on the HGHG scheme with multi-stage harmonic cascade. Without any additional modifications to the HGHG configuration, simulation results demonstrate the generation of intense 3 nm coherent FEL radiation using an external ultraviolet seed laser. This indicates an increase of the harmonic conversion number to approximately 90. A preliminary experiment is performed to evaluate the feasibility of this method. The proposed approach could potentially serve as an efficient method to broaden the wavelength coverage accessible to both existing and planned seeded X-ray FEL facilities.

The decay of a turbulent magnetic field is slower with helicity than without. Furthermore, the magnetic correlation length grows faster for a helical than a non-helical field. Both helical and non-helical decay laws involve conserved quantities: the mean magnetic helicity density and the Hosking integral. Using direct numerical simulations in a triply periodic domain, we show quantitatively that in the fractionally helical case the mean magnetic energy density and correlation length are approximately given by the maximum of the values for the purely helical and purely non-helical cases. The time of switchover from one to the other decay law can be obtained on dimensional grounds and is approximately given by $I_{H}^{1/2}I_{M}^{-3/2}$, where $I_{H}$ is the Hosking integral and $I_{M}$ is the mean magnetic helicity density. An earlier approach based on the decay time is found to agree with our new result and suggests that the Hosking integral exceeds naive estimates by the square of the same resistivity-dependent factor by which also the turbulent decay time exceeds the Alfvén time. In the presence of an applied magnetic field, the mean magnetic helicity density is known to be not conserved, and we show that then also the Hosking integral is not conserved.