This paper presents the design and characterization of a unit cell for dual-polarized liquid crystal (LC)-based reconfigurable intelligent surfaces (RIS), as well as an efficient, full-wave simulation methodology for the far-field beam-steering capabilities of large-scale LC-RIS. Within this framework, the unit cell relies on defected delay lines with a 4.6 μm thin LC layer aperture coupled to a patch antenna. This delay line architecture aims towards simultaneous optimization of loss, bandwidth and response time. Full-wave simulations of the unit cell in a periodic environment show an operating frequency between 26.5 and 29.5 GHz with wide angle radiation. Measurements of the unit cell in a 3 $\times$ 3 rectangular grid exhibit wideband impedance matching and overall good agreement with simulations. Furthermore, a simulation methodology is introduced that evaluates large-scale LC-RIS far-field beam-steering capabilities without requiring full-wave simulations of the entire structure, but just few unit cells. Within this scope, the LC-RIS achieves a maximum efficiency of 20.8% with a beam-steering range from −48° to +48°, despite the use of a lossy glass substrate and gold as a conductor. It exhibits a minimum bandwidth of 8.2% for an efficiency of at least 10% across all analyzed steering angles in E-Plane and H-Plane.

The aim of this paper is to review the latest evidence on food reformulation as a public health policy to improve our understanding of how different policy designs can drive reformulation and influence food system change. The focus is on three key nutrients of concern—trans fatty acids, salt and sugar.

In recent times, food reformulation has been categorised as either mandatory or voluntary, a distinction that can help assess policy effectiveness. However, this binary classification oversimplifies a far more complex landscape. Some policies—whether mandated by government or voluntarily suggested to industry—are explicitly intended to trigger reformulation. Others, by contrast, may have never been designed with the intention to encourage reformulation but have nonetheless prompted significant changes in product composition, intake and potential health outcomes.

Within what is commonly described as mandatory reformulation, for example, we find a broad mix of policy tools that operate very differently. Some, such as the UK’s Soft Drinks Industry Levy, were deliberately created to incentivise reformulation by applying financial pressure. Others, including front of pack nutrition labelling systems (particularly warning labels) and school food standards have encouraged reformulation only as a positive unintended consequence. These indirect drivers are not always evaluated for their impact on reformulation, which may lead to an incomplete understanding of their contribution to reducing intake nutrients of concern and health outcomes.

Nevertheless, emerging evidence suggests no single policy encourages reformulation alone, instead a combination of approaches are likely to drive it and contribute to meaningful and sustained food system change.

We study quasi-stationary distributions and quasi-limiting behaviour of Markov chains in general reducible state spaces with absorption. First, we consider state spaces that can be decomposed into two successive subsets (with communication possible in a single direction), differentiating between three situations, and characterize the exponential order of magnitude and the exact polynomial correction, called the polynomial convergence parameter, for the leading-order term of the semigroup for large time. Second, we consider general Markov chains with finitely or countably many communication classes by applying the first results iteratively over the communication classes of the chain. We conclude with an application of these results to the case of denumerable state spaces, where we prove existence for a quasi-stationary distribution without assuming irreducibility before absorption, but only aperiodicity, existence of a Lyapunov function, and existence of a point with almost surely finite return time.

The role of healthcare provider ownership in shaping health system performance remains contested. An umbrella review was conducted to synthesise evidence on the relationship between healthcare provider ownership and performance in high-income countries. Systematic reviews were included that examined performance of healthcare providers based on ownership status. Searches yielded 1,862 results, with 31 systematic reviews meeting the inclusion criteria, and one further systematic review identified through grey literature searches. Following the exclusion of 10 reviews classified as low-quality and two previous umbrella reviews both published in 2014, 20 reviews were eligible for data extraction and synthesis. Inconsistent evidence was found across reviews between healthcare provider ownership and several performance indicators including health outcomes, technical efficiency, and patient satisfaction. Private hospitals tend to serve wealthier patients, select less complex or costly patients, and charge higher payments for care than public comparators. Private for-profit (FP) providers of hospital and long-term care generally had poorer workforce outcomes than private not-for-profit or public providers, including reduced staffing levels, higher workloads, and lower job satisfaction. Private PF hospitals and nursing homes had improved financial performance based on revenues or profit margins. Our findings underscore the need for nuanced regulatory responses to the expansion of private FP provision within publicly funded systems.

Governments across the world are leveraging artificial intelligence (AI) to render services to citizens. Emerging economies are not left behind in this transformation but remain a gaping distance behind in their integration into public-sector service delivery compared to the private sector. To ensure the effective integration of AI services by government agencies to serve citizens, it is necessary to understand the constellation of factors driving user adoption of AI. Therefore, this study answers the question: how can government-initiated AI services be successfully accepted by citizens? Leveraging non-probability sampling, a snowball sample of 245 tertiary student-workers from across Ghana was surveyed to solicit their knowledge, attitudes, readiness, and use intentions towards AI-enabled government services. The data were analysed using FsQCA and complemented by PLS-SEM to confirm the findings. The findings reveal four unique configurations, summarised into two broad groups; AI enthusiasts and AI sceptics that drive AI adoption in government services. Positive readiness factors, such as knowledge of AI and optimism towards AI, characterise AI enthusiasts. In contrast, those described as AI sceptics still adopt government AI services despite their reservations and general distrust. AI sceptics are a delicate group that sit at the boundary between adoption and rejection, requiring special attention and strategies to orient them towards adoption. The study recommends effective education and trust-building strategies to foster AI adoption in government services. The findings are essential for driving the efficient implementation of AI-enabled services among working-class citizens in emerging economies.

This paper proposes a broadband, low-profile, dual-circularly polarized (CP) active phased array modular subarray. The subarray elements adopt dual-CP stacked microstrip patch antennas to expand the bandwidth. Each subarray has a complete structure and function, which can be used independently or extended to meet the requirements of different application scenarios. The impact of asymmetric plane is counteracted by a mirror-feed technique, which improves the consistency of scanning gain and axial ratio (AR) at both positive and negative angles. Meanwhile, the subarray can simultaneously form two beams of left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP) for scanning. Finally, a modular subarray prototype with an 8 × 8 array scale was simulated, fabricated, and measured. The simulation results show that the scanning gain decreases by less than 2.19 dB at ±45° and 5.4 dB at ±60° at the frequency of 12.1 GHz. Moreover, within the frequency range of 10.23–12.77 GHz (22.08%), the active voltage standing wave ratios (VSWR) of LHCP and RHCP in the azimuth and elevation dimensions of the subarray are below 2, and the AR in the beam scanning range of ±45° and ±60° are less than 3 and 6 dB, respectively.