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Do Plastic-free Alternatives Work in Practice? User Experience and Consumer Adaptation Under Mandatory Regulation
Item type: Journal Article
Tang H.S.; Ko J.; Lee H.F. (2026)
Mandatory plastic-reduction policies are central to reducing disposable waste, yet it remains unclear how consumers adapt when sustainable alternatives are imposed externally rather than voluntarily chosen. This study examines how users’ experiences with plastic-free disposable tableware are associated with adaptive attitudes under Phase I of Hong Kong’s Plastic-Free Regulation. Drawing on the Attitude–Behavior–Context framework, the analysis distinguishes between haptic experience and consumption experience to assess how tactile and functional evaluations relate to acceptance of mandated substitutes. The study employs a cross-sectional mixed-methods design based primarily on survey data from 1,458 respondents in Hong Kong, complemented by qualitative evidence for interpretation. The findings indicate that consumption experience is more consistently associated with adaptive attitudes than haptic experience, suggesting that functional performance matters more than initial sensory impressions in shaping acceptance. Attitudinal factors and social influences are also significantly associated with adaptation. The study contributes by showing that adaptation under mandatory sustainability regulation depends not only on environmental orientations but also on everyday product experience, identifying consumption experience as more salient than haptic experience and highlighting the importance of substitute quality and service environments in the practical success of plastic-free transitions.
Euclid preparation: CXII. Baryon acoustic oscillations extraction techniques: comparison and optimisation
Item type: Journal Article
Sarpa E.; Veropalumbo A.; Bonici M.; et al. (2026)
We present the first end-to-end validation of the Euclid baryon acoustic oscillation (BAO) analysis pipeline, encompassing density-field reconstruction, two-point correlation function measurement, and cosmological parameter inference. Using eight Euclid-like mock catalogues extracted from each of the four snapshots of the Flagship 1 (FS1) simulation, which is designed to replicate the statistical properties of the first Euclid data release (DR1), we assessed the performance of the two standard BAO reconstruction methods based on the Zeldovich approximation, RECSYM and RECISO, in four redshift snapshots (0.9 ≤ z ≤ 1.8). The pipeline introduces several methodological advances: an emulator-based model evaluator (Bora.jl) combined with a Hamiltonian Monte Carlo sampler (NUTS), achieving a speed-up of more than 500 times relative to standard Monte Carlo Markov chains, and a semi-analytical covariance estimator (BeXiCov+WinCov) that enables robust error estimates with only eight mock realisations and remains stable under variations in the fiducial cosmology. Together, these components ensure computational efficiency while significantly reducing the risk of underestimating the parameter uncertainties. The two reconstruction schemes yield unbiased BAO measurements for all redshifts and user-defined choices, including the smoothing scale and fiducial cosmology. In each snapshot, reconstruction enhances the figure of merit for {Ωm, H0 rs} by a factor of ∼3, which is equivalent to tripling the effective survey volume. When we combined the four redshift bins, the improvement remained substantial, with BAO-only constraints reaching ∼10% precision on Ωm and ∼3% on H0 rs. The results from RECSYM and RECISO are consistent within the uncertainties, but we recommend RECSYM during testing because its sensitivity to covariance variations is lower. These findings establish the accuracy, robustness, and scalability of the Euclid BAO pipeline for DR1 and provide a solid foundation for future cosmological analyses.
SPHERE/ZIMPOL observations of the symbiotic system R Aquarii : II. Dynamics of the dust in the Mira wind and the Hα gas in the jet
Item type: Journal Article
Schmid H.M.; Lagadec E.; Milli J.; et al. (2026)
Context. R Aqr is a resolved symbiotic Mira binary and a prototype target for the study of complex hydrodynamic processes including dust-driven mass loss, mass transfer, accretion, and jet outflows and the formation of strongly asymmetric circumstellar structures. Aims. With the aim of gaining a better understanding of the complex hydrodynamics of R Aqr, we conducted an investigation based on new high-resolution imaging of the Hα emission from the ionized gas and of the polarization from scattering dust. Methods. We analyzed SPHERE/ZIMPOL Hα and polarization maps with a resolution of ≈25 mas (5 AU) for the innermost region – r ≲ 2″ (≲400 AU) – of the R Aqr system. Data for four epochs were taken covering 6.7 years, including the dust eclipse phase around 2021, providing the angular motion and structural changes for the Hα and dust clouds, which are measured and described in detail. The results are compared with literature data and put into context with respect to models for AGB star binaries. Results. The central Hα emission traces the orbital motion of the hot component. The circumstellar polarization from scattering dust shows interaction effects near the binary (≲60 AU), including a flattened distribution aligned with the orbital plane, corotating dust, and a reduction of the scattering signal during the dust eclipse phase. The polarization shows for ≳60 AU a steady outflow with about a dozen dust clouds, a few of which have a comet-like core and tail features. The dust velocity is about 20 km s−1, and this is faster than for the CO gas measured with ALMA. Several prominent Hα clouds near the binary (≲200 AU) also show scattering polarization because they are just partly ionized dust clouds from the Mira wind. We also found small faster-moving transient Hα clouds, pointing to outflow instabilities such as those in clumpy winds of hot stars. The observed temporal changes of the Hα emission, in particular the overall angular shift during the dust eclipse event, can be explained by strong illumination changes from the hot component. At a larger separation (≳500 AU), the Hα clouds move faster (> 100 km s−1), in agreement with previous studies. This acceleration in the outflow is probably a result of gas heating by photoionization and shocks in the clumpy outflow, and the produced overpressure gives rise to the two well-known jet-like features expanding in polar directions. Conclusions. Monitoring of the inner regions of R Aqr shows the motion and evolution of different structures in the dusty Mira wind and the ionized outflow of the hot component, and these features provide unambiguous information about the hydrodynamics of the circumstellar material. Such observations are very useful to clarify the complex phenomena taking place in interacting binaries with asymptotic giant branch stars.
Water-rich sub-Neptunes and rocky super-Earths around different stars: Radii shaped by volatile partitioning, formation, and evolution
Item type: Journal Article
Burn R.; Bali K.; Dorn C.; et al. (2026)
Context. Despite precise characterization measurements, the nature of planets with radii between 2 and 4 Earth radii – sub-Neptunes – remains unknown due to degeneracies in interior models. Nevertheless, the field has compiled an impressive ensemble of small planets with measured masses and radii orbiting different stars. Aims. This dataset can be used to test the prediction of large water reservoirs on sub-Neptunes, as proposed by planet formation theory with orbital migration. We aim to determine whether this water reservoir is included in photoevaporative winds and how much of it can partition into the rocky and metallic interior. Methods. We coupled the results of a planetary formation model with planetesimal and gas accretion as well as orbital migration with evolution models that assume either perfect mixing of water with H/He in the envelope or complete segregation. For the mixed envelopes, we also included an analytic treatment of fractionation during photoevaporative mass loss. Furthermore, we studied the effect of equilibrium dissolution of water into an assumed magma ocean and metallic core for the first time in coupled formation-evolution models. Results. Out of the tested scenarios, the mass–radius relation of exoplanets is relatively well matched by all scenarios where the atmosphere is of mixed composition. The agreement depends on mass, with better consistency for the model without dissolution below 3 Earth masses and hints of the opposite at higher masses. Fractionation is not found to significantly alter the properties of the planets for our initial conditions due to initially massive envelopes on all planets. For all scenarios, we quantified the radius valley location and its scaling with stellar mass. Conclusions. The mass–radius relations for water-rich sub-Neptunes are broadly consistent with observations. However, statistical surveys in both mass and radius are required to distinguish between the scenarios. The mixed-composition loss of different volatiles, their dissolution into the planetary interior, and the solidification of the magma ocean are natural next steps toward a comprehensive atmosphere-interior evolution model.
Tree crown mortality and defoliation assessment in temperate forests using aerial imagery and deep learning
Item type: Journal Article
Beloiu M.; Berger E.; Ecke S.; et al. (2026)
Forest health is increasingly threatened by global warming and recurrent droughts. However, limited long-term data on tree health and mortality restricts our ability to detect trends and predict forest responses to climate stressors. Traditional methods for assessing tree defoliation are accurate but costly and labor-intensive, highlighting the need for scalable alternatives. This study aims to develop a more automated approach for monitoring tree defoliation and mortality in Germany and Switzerland using deep learning applied to freely available aerial imagery. We assessed crown vitality using three and four defoliation classes derived from field surveys. A Convolutional Neural Network (CNN) was trained on 48,388 annotated tree crowns from aerial imagery, labeled with forest type and defoliation status. RGB and NDVI-GB inputs were tested using five-fold and spatial-block cross-validation to ensure robustness. The three-class model outperformed the four-class CNN object detection version. RGB and NDVI-GB bands produced similar results in the three-class setup, with F1-scores of 0.74 and 0.73, respectively. Defoliated trees were more challenging to detect (F1-conifer: 0.61, F1-broadleaf: 0.54). Dead trees were detected with high accuracy (F1-score: 0.97), while healthy trees also showed good performance (F1-conifer: 0.78, F1-broadleaf: 0.73). Repeated aerial imagery revealed a 17-fold increase in standing dead trees across a 977-ha protected forest between 2014 (1,062 trees) and 2022 (17,897 trees), with 90 % of the increase after 2018. This study demonstrates that RGB imagery alone is sufficient for operational, tree-level monitoring of both defoliation and mortality over time. As more countries acquire repeated aerial imagery, this study offers broad applicability and supports forest inventories and resilient management strategies.