Analysis of source regions and transport pathways of sub-micron aerosol components in Europe

Preprint versio

Enhancing LLM robustness to perturbed instructions: an empirical study

Large Language Models (LLMs) are highly vulnerable to input perturbations, as even a small prompt change may result in a substantially different output. Existing methods to enhance LLM robustness are primarily focused on perturbed data samples, whereas improving resiliency to perturbations of task-level instructions has remained relatively underexplored. In this work, we focus on character- and word-level edits of task-specific instructions, which substantially degrade downstream performance. We experiment with a variety of techniques to enhance the robustness of LLMs, including self-denoising and representation alignment, testing different models (Llama 3 and Flan-T5), datasets (CoLa, QNLI, SST-2) and instructions (both task-oriented and role-oriented). We find that, on average, self-denoising—whether performed by a frozen LLM or a fine-tuned model—achieves substantially higher performance gains than alternative strategies, including more complex baselines such as ensembling and supervised methods

Are food taxes for healthy eating acceptable? A survey of public attitudes in the UK

Introduction Appropriately designed food taxes can improve diet quality and health. Fiscal levers are used in several countries to combat the rise in obesity and diet-related diseases. This study aims to investigate public attitudes, knowledge and policy preferences regarding food taxes for promoting healthy eating in the UK. Methods A survey was administered through YouGov Plc to a nationally representative sample of 2125 adults, gathering information on: acceptability and support for different types of food taxes, awareness and knowledge of existing taxes and preferences for the characteristics of possible new taxes. Results Overall, 48% of respondents support higher taxes on unhealthy foods, rising to 72% if taxes made healthy foods more affordable. Respondents with high socioeconomic status and those living in London showed the highest support. Respondents had limited awareness of existing food and beverage taxes and prioritised discretionary items such as cakes and crisps for possible increased taxation. Conclusions The survey shows a high level of support for taxing unhealthy foods, as well as concern for the affordability of healthy foods. A carefully designed holistic approach to food taxation can be part of a wider public health strategy and can be favourably met by the general population in the UK

Time encoding via unlimited sampling: theory, algorithms and hardware validation

An alternative to conventional uniform sampling is that of time encoding, which converts continuous-time signals into streams of trigger times. This gives rise to Event-Driven Sampling (EDS) models. The data-driven nature of EDS acquisition is advantageous in terms of power consumption and time resolution and is inspired by the information representation in biological nervous systems. If an analog signal is outside a predefined dynamic range, then EDS generates a low density of trigger times, which in turn leads to recovery distortion due to aliasing. In this paper, inspired by the Unlimited Sensing Framework (USF), we propose a new EDS architecture that incorporates a modulo nonlinearity prior to acquisition that we refer to as the modulo EDS or MEDS. In MEDS, the modulo nonlinearity folds high dynamic range inputs into low dynamic range amplitudes, thus avoiding recovery distortion. In particular, we consider the asynchronous sigma-delta modulator (ASDM), previously used for low power analog-to-digital conversion. This novel MEDS based acquisition is enabled by a recent generalization of the modulo nonlinearity called modulo-hysteresis. We design a mathematically guaranteed recovery algorithm for bandlimited inputs based on a sampling rate criterion and provide reconstruction error bounds. We go beyond numerical experiments and also provide a first hardware validation of our approach, thus bridging the gap between theory and practice, while corroborating the conceptual underpinnings of our work

Association between catastrophic health expenditure and mortality in older people in 11 European Health Systems: a longitudinal analysis between 2006 and 2020

Introduction Out-of-pocket expenditure (OOPE) and catastrophic health expenditure (CHE) challenge the financial protection provided by European health systems. Despite rising OOPE and CHE in Europe, evidence on health impact remains limited. This study examines the association between OOPE, CHE, and all-cause mortality in older adults across 11 European countries from 2006 to 2020. Methods We analysed longitudinal data from the Survey of Health, Ageing and Retirement in Europe, including 70,367 individuals aged ≥50 years across five waves (wave 2 [2006/7], 5 [2013], 6 [2015], 7 [2017], and 8 [2019/20]). CHE was defined as annual OOPE exceeding 25% of household income. Parametric survival models with Gompertz distribution estimated the association between CHE, OOPE, and mortality, adjusting for socioeconomic and clinical covariates. Sensitivity analyses employed inverse probability weighting with regression adjustment. Results Participants had a mean age of 65 years, 54% were female, and 46% were retired. CHE was incurred by1.6% of participants (range: 0.9%–2.2% by country). Over a mean follow-up of 3.8 years, 10.2% (7,193) died. CHE was associated with an 84% increased mortality risk (95%CI 1.66–2.04), with the strongest effect in Switzerland (HR 4.22;95%CI 2.54–7.00). Each €100 increase in total OOPE was associated with a 0.4% higher mortality risk (95%CI 1.002–1.006), especially in higher-income groups. OOPE on medicines showed heterogeneous effects: in the lowest income quintile, higher spending was associated with reduced mortality (HR 0.955;95%CI 0.927–0.982), while in the third quintile (HR 1.044;95%CI 1.017-1.071) and in countries like Czechia (HR 1.086;95%CI 1.017-1.159) and Germany (HR 1.015;95%CI 1.003-1.028), it was associated with increased mortality. Sensitivity analyses confirmed the main results. Conclusions CHE and elevated OOPE are independently associated with increased mortality in older Europeans, suggesting negative long-term impacts on health. These findings underscore the need for cost-sharing reforms to preserve equity and protect vulnerable populations

Probing oxygen ion transport in solid state oxides: a technical review

The study of ion transport in solid state ionic materials underpins the fast development of many electrochemical technologies such as solid state batteries, solid oxide cells, proton conducting solid oxide fuel cells. In order to obtain the ion transport dynamics, different in situ and ex situ techniques have been developed to probe ion transport while each method has its inherent merits and weaknesses. The choice of the method for measuring ionic mass transport primarily depends upon the appropriacy and accessibility of the technique based on sample properties, targeted information of interest and technical limitations. This review introduces aspects of the underlying principles, discusses and compares different techniques available to date in the literature to obtain oxygen mass transport kinetics, primarily focussing on experimental techniques, in particular the isotope exchange depth profiling and electrical conductivity relaxation methods, together with a brief introduction on computational tools

Automated strategy for probing enzymatic degradation of lipid membranes

The demand for automated workflows has significantly increased within academia, as they offer improvements in experimental efficiency, reproducibility and data quality. By minimising human intervention, automated systems reduce the potential for user error and enable high-throughput experiments, which are particularly valuable for large-scale or repetitive studies. Lab-on-a-chip technologies are adopted as a cost-effective and flexible strategy in research areas such as enzyme kinetics and membrane biophysics. These platforms lower reagent consumption and facilitate precise control over experimental conditions. In this thesis, a millifluidic chip was first employed to study the permeability of a model membrane using droplet interface bilayers, followed by the integration of a model physical barrier to mimic more biologically relevant conditions. This thesis also presents a low-cost, automated, custom-built flow-controlled spectrometer, equipped with a millifluidic mixing chip. The chip enables homogeneous on-chip mixing while the mini spectrometer allows real-time absorbance and fluorescence measurements. The system was utilised to investigate the Sphingomyelinase-induced degradation of lipid membranes, in which the enzyme catalyses the hydrolysis of sphingomyelin and converts it into ceramide. Various factors influencing the reaction were systematically examined, including enzyme concentrations, lipid composition, and the acyl chain length of SM. In addition to spectroscopic analysis, microscopy was employed to visualise membrane morphology changes, offering deeper insights into the enzymatic reaction. Finally, the system was integrated with an iterative feedback loop designed to optimise the reaction conditions. These results contribute to various research areas by providing a comprehensive and accessible platform for studying membrane biophysics through the integration of low-cost millifluidic technology and real-time spectroscopic analysis.Open Acces

Optimizing the Au particle doping size for enhanced photocatalytic disinfection under low-intensity visible light

Here, we present the effect of 1.2–9.9 nm Au particles on crystal violet-treated polymer under a low intensity of visible light. The use of Au particles ≤ 6.3 nm promoted charge carrier transfer from crystal violet to Au particles. Photospectroscopy analyses and DFT computations revealed that a change in the electronic band structure caused by the size reduction of the particle altered the charge carrier transfer pathway in crystal violet. Especially for crystal violet─1.2 nm Au particles, charge carrier transfer predominantly occurs at the S1 of crystal violet because the T1 state lacks sufficient potential energy for transfer. 1.2 nm Au particles on crystal violet not only most significantly enhanced the generation of O2•–, H2O2, and •OH by minimizing unnecessary side reactions or energy loss but also showed the most potent disinfection activity against Staphylococcus aureus, even at low visible light flux levels (0.037–0.054 mW cm–2), which resulted in a 5.3 log reduction in viable bacteria after 6 h exposure to visible light. This finding provides fundamental insights into the Au effect as a cocatalyst in photocatalysts and the development of light-activated self-sterilizing surfaces that can be applied to various hospital surfaces to prevent the spread of pathogens, which remains a global challenge

Rhythm control benefits left ventricular function compared to rate control in patients with atrial fibrillation – a computational study

Background Atrial fibrillation (AF) alters heart rate, rhythm regularity, and atrial contraction, which may contribute to an increased risk of heart failure. While rate and rhythm control target different aspects of these disturbances, their specific effects on left ventricular (LV) function remain unclear. Objective To predict the independent and combined contribution of heart rate, rhythm regularity and atrial contraction to LV function in AF patients. Methods We predicted LV ejection fraction (EF) and stroke volume (SV) in 10 whole-heart patient-specific AF patient models while varying heart rate, rhythm regularity and effectiveness of atrial contraction. AF was modeled as a fast, irregular heart rate with no atrial contraction. Pharmacological and paced rate control were modeled as a slow irregular and regular heart rate without atrial contraction, respectively, while rhythm control had a slow, regular heart rate with atrial contraction. Results Rhythm control resulted in a greater improvement in LVEF than pharmacological rate control compared to AF (+5.1 ± 0.4% vs +2.8 ± 0.3%, P<0.01). Paced rate control was equivalent to pharmacological rate control in terms of LVEF (+2.6 ± 0.4% vs +2.8 ± 0.3%). Atrial contraction did not improve ventricular function in the presence of an irregular heart rate (pharmacological rate: +2.8 ± 0.3% vs rhythm with irregular heart rate: +2.7 ± 0.3%). Conclusion Rhythm control provides superior improvements in LV function compared to rate control. However, restoring sinus rhythm may yield limited benefits to LV function when atrial contraction is ineffective or when heart rate is irregular