New South Wales (NSW) Health is committed to enhancing child health and development during the first 2000 days (conception to 5 years)(1). However, in Australia current child health behaviours indicate the need for further improvements. For example, discretionary foods (contributing high amounts of saturated fat, energy, added sodium and sugar) account for approximately 30% of total energy intakes in 2–3 years olds including the consumption of sugar sweetened beverages (SSB)(2). There remains a need to provide all parents raising children with direct and sustained support from birth to maximise health behaviours during this important life stage. Healthy Beginnings for HNEKids (HB4HNEKids) is an innovative text messaging program designed to be integrated into the usual care provided by Child and Family Health Nursing (CFHN) services. The messages were co-designed with key stakeholders to provide age-and-stage relevant preventive health information to parents/carers during the first 2000 days. HB4HNEKids has been piloted within five diverse CFHN services within the Hunter New England (HNE) local health district of NSW, reaching over 6000 families since its launch. However, the efficacy of the program on child health behaviours has not yet been explored. The aim of this study is to explore if families that received the HB4HNEKids program report reduced frequency of child discretionary food intake and a lower prevalence of SSB exposure, compared to families who did not receive the program. A cross-sectional survey of mothers 12–14 months post-partum was conducted between August 2023 and July 2024 including participants that received HB4HNEKids and a concurrent non-randomised comparison group, located in HNE. Mothers were asked to report on the frequency of child discretionary food intake per week, and whether their child had ever received SSB (including sweetened water, cordial, fruit drink, and soft-drinks). We conducted linear regression and logistic regression analyses to explore differences between the intervention and comparison participants. A total of 283 participants completed the survey, including 104 (37%) participants that had received the HB4HNEKids program. In infants aged 12–14 months, the frequency of discretionary food intake was approximately 1 serve per week and was unchanged based on if the family had received the HB4HNEKids program or not. Despite a 6-point prevalence difference in SSB exposure reported between groups (HB4HNEKids: 19.42% vs Comparison: 26.26%), this difference was not statistically significant (OR: 0.68 (95% CI: 0.37, 1.23), p = 0.2). Australian infant feeding guidelines suggest that the consumption of nutrient poor discretionary foods and sugar sweetened beverages should be avoided or limited(3). The HB4HNEKids program demonstrates some promise for improving infant feeding behaviours, however a larger effectiveness trial is required to ensure the evaluation is adequately powered.

Optimising stellarators for quasisymmetry leads to strongly reduced collisional transport and energetic particle losses compared with unoptimised configurations. Although stellarators with precise quasisymmetry have been obtained in the past, it remains unclear how broad the parameter space is where good quasisymmetry may be achieved. We study the range of aspect ratios and rotational transform values for which stellarators with excellent quasisymmetry on the boundary can be obtained. A large number of Fourier harmonics is included in the boundary representation, which is made computationally tractable by the use of adjoint methods to enable fast gradient-based optimisation and by the direct optimisation of vacuum magnetic fields, which converge more robustly compared with solutions from magnetohydrostatics. Several novel configurations are presented, including stellarators with record levels of quasisymmetry on a surface, three field period quasiaxisymmetric stellarators with substantial magnetic shear, and compact quasisymmetric stellarators at low aspect ratios similar to tokamaks.

A new approach for constructing polar-like boundary-conforming coordinates inside a toroid with strongly shaped cross-sections is presented. A coordinate mapping is obtained through a variational approach, which involves identifying extremal points of a proposed action in the mapping space from $[0, 2{\rm \pi} ]^2 \times [0, 1]$ to a toroidal domain in $\mathbb {R}^3$. This approach employs an action built on the squared Jacobian and radial length. Extensive testing is conducted on general toroidal boundaries using a global Fourier–Zernike basis via action minimisation. The results demonstrate successful coordinate construction capable of accurately describing strongly shaped toroidal domains. The coordinate construction is successfully applied to the computation of three-dimensional magnetohydrodynamic equilibria in the GVEC code where the use of traditional coordinate construction by interpolation from the boundary failed.

The Buffalo National River in northwest Arkansas preserves an extensive Quaternary record of fluvial bedrock incision and aggradation across lithologies of variable resistance. In this work, we apply optically stimulated luminescence (OSL) dating to strath and fill terraces along the Buffalo River to elucidate the role of lithology and climate on the development of the two youngest terrace units (Qtm and Qty). Our OSL ages suggest a minimum strath planation age of ca. 250 ka for the Qtm terraces followed by a ca. 200 ka record of aggradation. Qtm incision likely occurred near the last glacial maximum (LGM), prior to the onset of Qty fill terrace aggradation ca. 14 ka. Our terrace ages are broadly consistent with other regional terrace records, and comparison with available paleoclimatic archives suggests that terrace aggradation and incision occurred during drier and wetter hydrological conditions, respectively. Vertical bedrock incision rates were also calculated using OSL-derived estimates of Qtm strath planation and displayed statistically significant spatial variability with bedrock lithology, ranging from ~35 mm/ka in the higher resistance reaches and ~16 mm/ka in the lower resistance reaches. In combination with observations of valley width and terrace distribution, these results suggest that vertical processes outpace lateral ones in lithologic reaches with higher resistance.

Anisotropic heat conduction in a plasma embedded in a magnetic field with irregular, possibly chaotic, field lines is discussed. If the collisional mean free path exceeds the electron gyroradius, the heat conductivity is much larger along the field lines than across them, and this enhances the transport across a domain where good flux surfaces do not exist. Recognising that anisotropic heat conduction may be cast in a variational form, and by constructing increasingly sophisticated trial functions that are based on invariant and almost-invariant structures under the magnetic field-line flow, bounds are derived on this enhancement and on the temperature variation along the magnetic field. In this way, remarkably accurate approximations for the temperature can be rapidly constructed without solving the diffusion equation, even in the small perpendicular-diffusion limit when the solution for the temperature is dominated by the fractal structure the magnetic field lines.

Given the large anisotropy of transport processes in magnetized plasmas, the magnetic field structure can strongly impact heat diffusion: magnetic surfaces and cantori form barriers to transport while chaotic layers and island structures can degrade confinement. When a small but non-zero amount of perpendicular diffusion is included, the structure of the magnetic field becomes less important, allowing pressure gradients to be supported across chaotic regions and island chains. We introduce a metric for the effective volume over which the local parallel diffusion dominates based on the solution to the anisotropic heat diffusion equation. To validate this metric, we consider model fields with a single island chain and a strongly chaotic layer for which analytic predictions of the relative parallel and perpendicular transport can be made. We also analyse critically chaotic fields produced from different sets of perturbations, highlighting the impact of the mode number spectrum on the heat transport. Our results indicate that this metric coincides with the effective volume of non-integrability in the limit $\kappa _{\perp } \rightarrow 0$, where $\kappa_{\perp}$ is the perpendicular diffusion coefficient. We propose that this metric be used to assess the impact of non-integrability on the heat transport in stellarator equilibria.

Adjoint methods can speed up stellarator optimisation by providing gradient information more efficiently compared with finite-difference evaluations. Adjoint methods are herein applied to vacuum magnetic fields, with objective functions targeting quasi-symmetry and a rotational transform value on a surface. To measure quasi-symmetry, a novel way of evaluating approximate flux coordinates on a single flux surface without the assumption of a neighbourhood of flux surfaces is proposed. The shape gradients obtained from the adjoint formalism are evaluated numerically and verified against finite-difference evaluations.

The headwaters of the Río Pilcomayo drain the Cerro Rico de Potosí precious metal-polymetallic tin deposits of southern Bolivia. Mining of these deposits has taken place for around 500 years, leading to severe contamination of the Pilcomayo's waters and sediments for at least 200 km downstream. Communities living downstream of the mines and processing mills rely on the river water for irrigation, washing and occasionally, cooking and drinking, although most communities take their drinking water from springs located in the mountains above their village. This investigation focuses on arsenic exposure in people living in riverside communities up to 150 km downstream of the source. Sampling took place in April–May 2003 (dry season) and was repeated in January–March 2004 (wet season) in five communities: El Molino, Tasapampa, Tuero Chico, Sotomayor and Cota. Cota was the control in 2003 and again in 2004; a nearby city, Sucre, and several locations in the UK were also used as controls in 2004. Drinking, irrigation and river waters, hair and urine samples were collected in each community, digested where appropriate and analysed for As using ICP-MS. Arsenic concentrations in drinking waters ranged 0.2–112 μg 1–1, irrigation water 0.6–329 μg 1–1, river waters 0.9–12,800 μg 1–1, hair 37–2110 μg kg–1 and urine 11–891 μg 1–1. All but one drinking water sample was found to contain As below the World Health Organization recommended guideline of 10 μg 1–1, although a number of irrigation and river water concentrations were above Canadian and Bolivian guidelines. Many As concentrations in the hair and urine samples from this study exceeded published values for non-occupationally exposed subjects. Analysis of mean concentration values for all media types showed that there were no statistically significant differences between the control locations and the communities exposed to known As contamination, suggesting that the source of As may not be mining-related. Arsenic concentration appears to increase as a function of age in hair samples from males and females older than 30 years. Male volunteers over the age of 35 showed increasing urine-As concentrations as a function of age, whereas the opposite was true for the females.

A numerical investigation is carried out to understand the equilibrium $\unicode[STIX]{x1D6FD}$ -limit in a classical stellarator. The stepped-pressure equilibrium code (Hudson et al., Phys. Plasmas, vol. 19 (11), 2012) is used in order to assess whether or not magnetic islands and stochastic field-lines can emerge at high $\unicode[STIX]{x1D6FD}$ . Two modes of operation are considered: a zero-net-current stellarator and a fixed-iota stellarator. Despite the fact that relaxation is allowed (Taylor, Rev. Mod. Phys., vol. 58 (3), 1986, pp. 741–763), the former is shown to maintain good flux surfaces up to the equilibrium $\unicode[STIX]{x1D6FD}$ -limit predicted by ideal-magnetohydrodynamics (MHD), above which a separatrix forms. The latter, which has no ideal equilibrium $\unicode[STIX]{x1D6FD}$ -limit, is shown to develop regions of magnetic islands and chaos at sufficiently high $\unicode[STIX]{x1D6FD}$ , thereby providing a ‘non-ideal $\unicode[STIX]{x1D6FD}$ -limit’. Perhaps surprisingly, however, the value of $\unicode[STIX]{x1D6FD}$ at which the Shafranov shift of the axis reaches a fraction of the minor radius follows in all cases the scaling laws predicted by ideal-MHD. We compare our results to the High-Beta-Stellarator theory of Freidberg (Ideal MHD, 2014, Cambridge University Press) and derive a new prediction for the non-ideal equilibrium $\unicode[STIX]{x1D6FD}$ -limit above which chaos emerges.