Articles publicats en revistes (Institut de Recerca en Sistemes Complexos (UBICS))

Permanent URI for this collectionhttps://hdl.handle.net/2445/119662

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Embedding Citizen Science in Galleries, Libraries, Archives, and Museums to Address Urban Sustainability Challenges: a Cross-Case Analysis in Four European Cities.
(Ubiquity Press, 2026-08-28) Bonhoure, Isabelle; Magee, Rebekah; Peer, Christian; Guba, Beate; Harnacker, Sebastian; Yankelevich, Tanya; Dembski, Fabian; Segura Domènech, Raquel; Perelló, Josep, 1974-
Herein, we examine the interaction between galleries, libraries, archives, and museums (GLAMs) and citizen science (CS) through the empirical analysis of five pilots addressing urban sustainability challenges. In Barcelona, a university partnered with a public library to assess heat exposure in public spaces. In Delft, children’s perceptions of urban spaces were collected and discussed through a collaboration between a university and a public library. In Tallinn, a community museum supported the testing of a digital visualization tool to enhance citizens’ feedback in urban planning. In Vienna, an urban research institute and an academic library co-designed two pilots addressing urban heat and the transformation of public spaces. Findings draw on GLAMs’ distinct contributions, the structural organization of the pilots, and the perceptions of librarians and researchers, gathered through surveys, interviews, and collective writing processes. A strong community-oriented focus and the engagement of underrepresented groups were common features across all pilots, though organizational structures and actor typologies varied by city. GLAMs consistently functioned as powerful connectors between researchers, citizens, and local stakeholders. Embedding CS initiatives within GLAM social and community-oriented venues can help mitigate power imbalances and foster more horizontal, mutual learning between academics and GLAM staff. GLAMs can also provide the crucial social infrastructure to significantly embed sustainability-focused CS initiatives across diverse knowledge ecosystems, countries, and urban contexts.
Kinetic Description of Viral Capsid Self-Assembly Using Mesoscopic Non-Equilibrium Thermodynamics
(MDPI, 2025-03-08) Peña, Jason; Dagdug, Leonardo; Reguera, D. (David)
The self-assembly mechanisms of various complex biological structures, including viral capsids and carboxysomes, have been theoretically studied through numerous kinetic models. However, most of these models focus on the equilibrium aspects of a simplified kinetic description in terms of a single reaction coordinate, typically the number of proteins in a growing aggregate, which is often insufficient to describe the size and shape of the resulting structure. In this article, we use mesoscopic non-equilibrium thermodynamics (MNET) to derive the equations governing the non-equilibrium kinetics of viral capsid formation. The resulting kinetic equation is a Fokker–Planck equation, which considers viral capsid self-assembly as a diffusive process in the space of the relevant reaction coordinates. We discuss in detail the case of the self-assembly of a spherical (icosahedral) capsid with a fixed radius, which corresponds to a single degree of freedom, and indicate how to extend this approach to the self-assembly of spherical capsids that exhibit radial fluctuations, as well as to tubular structures and systems with higher degrees of freedom. Finally, we indicate how these equations can be solved in terms of the equivalent Langevin equations and be used to determine the rate of formation and size distribution of closed capsids, opening the door to the better understanding and control of the self- assembly process.
A continuum model to study fluid dynamics within oscillating elastic nanotubes
(Cambridge University Press (CUP), 2021-04-06) Torres-Herrera, Ulises; Corvera Poiré, Eugenia
We derive equations of motion that describe the dynamics of a fluid confined within an elastic nanotube subject to periodic bending deflections. We use the principle of least action applied to a continuous open system at constant temperature. We solve the equations analytically in two limiting situations: when the tube oscillations are so small that they do not affect the fluid motion, but this one affects the tube dynamics; and when the flow magnitude is so small that it has no influence on the tube dynamics, but this one affects fluid motion. In the first case, we find out that the characteristic bending frequency spectrum of the tube depends not only on the magnitude of flow velocity, as previously stated in the literature, but also on the fluid velocity profile. This could constitute the basis of a strategy for indirect determination of the slip length in carbon nanotubes conveying flow via measurement of the buckling speed. In the second case, we find that tube vibrations can modify the dynamics of the fluid. Particularly, for a fluid subject to a constant pressure gradient, the tube motion induces an oscillatory motion in the fluid with twice the frequency of the tube. Moreover, the amplitude of the oscillatory fluid motion persists at high frequencies. This could constitute a strategy to generate high-frequency flows at nanoscales. Our results open up a panorama to control flow across nanotubes via tube vibrations, which could be complementary to chemical functionalization of nanostructures.
Curvature induces and enhances transport of spinning colloids through narrow channels
(Royal Society of Chemistry, 2024-09-09) Cereceda López, Eric; Corato, Marco de; Pagonabarraga Mora, Ignacio; Meng, Fanlong; Tierno, Pietro; Ortiz-Ambriz, Antonio
The effect of curvature and how it induces and enhances the transport of colloidal particles driven through narrow channels represent an unexplored research avenue. Here we combine experiments and simulations to investigate the dynamics of magnetically driven colloidal particles confined through a narrow, circular channel. We use an external precessing magnetic field to induce a net torque and spin the particles at a defined angular velocity. Due to the spinning, the particle propulsion emerges from the different hydrodynamic coupling with the inner and outer walls and strongly depends on the curvature. The experimental findings are combined with finite element numerical simulations that predict a positive rotation translation coupling in the mobility matrix. Further, we explore the collective transport of many particles across the curved geometry, making an experimental realization of a driven single file system. With our finding, we elucidate the effect of curvature on the transport of microscopic particles which could be important to understand the complex, yet rich, dynamics of particle systems driven through curved microfluidic channels.
Citizen science contributions to sustainable urban transformation, urban sustainability and urban planning: A systematic literature review
(Elsevier, 2026-07-01) Bonhoure, Isabelle; Guba, Beate; Peer, Christian; Labastida i Juan, Ignasi, 1970-; Perelló, Josep, 1974-
Urban areas face complex sustainability challenges that demand new approaches to knowledge production. While citizen science (CS) is increasingly recognised as a promising avenue in scientific research, its specific contributions to urban sustainability, sustainable urban transformation, and urban planning remain insufficiently synthesised. This systematic literature review analyses academic publications that explicitly reference CS to clarify its current and potential roles in these domains. Our review identifies a marked increase in scholarly attention—between 2022 and 2024—reflecting the growing recognition of CS as a valuable approach for addressing urban sustainability issues. Using the bibliometric-network tool VOSviewer, we reveal three major thematic clusters: (1) biodiversity, ecology, and conservation; (2) methodologies and practices; and (3) humans and communities. Well-established strands, especially in biodiversity and conservation, highlight the long-standing integration of CS into species monitoring, ecological assessment, and food-production initiatives. The role of citizens emerges as highly diverse, ranging from experiential experts to collaborative data producers. More recent work points to emerging interdisciplinary applications linking community engagement with environmental health, public health, and climate change. Despite this momentum, key gaps remain. These include the limited participation of underserved communities as well as still weak integration with environmental and climate-justice frameworks. Addressing these gaps is critical for fulfilling the transformative role that supranational bodies already assign to CS in tackling contemporary urban sustainability challenges.
Genome-wide interaction analysis of long-term trihalomethane exposure in drinking water and colorectal cancer risk in a Spanish Multicenter Case-Control Study (MCC-Spain)
(Elsevier Ltd., 2026-01-11) Moratalla Navarro, Ferran; Obón Santacana, Mireia; Rius Sansalvador, Blanca; Guinó, Elisabet; Moragas, Núria; Donat Vargas, Carolina; Fernández de Larrea-Baz, Nerea; Molina Barceló, Ana; Guevara, Marcela; Morón-Duran, Francisco D; Dierssen Sotos, Trinidad; Tardón, Adonina; Castaño-Vinyals, Gemma; Cabrera Castro, Natalia; Molina, Antonio J.; Aizpurua Atxega, Amaia; Morales Suárez Varela, María M.; Martín, Vicente; Fernández Navarro, Pablo; Villanueva, Cristina M.; Moreno Aguado, Víctor
We conducted a genome-wide interaction analysis between long-term exposure to trihalomethanes in drinking water and colorectal cancer (CRC) risk in a multicenter case-control study in Spain, including 1037 CRC cases and 2100 controls. Exposure categories were estimated based on sex-specific median and quartile values of total trihalomethanes (TTHM), chloroform (CHCl3), and brominated trihalomethanes (Br-THMs) among controls. In addition, TTHM exposure was assessed relative to the WHO guideline thresholds. Gene-environment interaction models were computed with the GxEScanR package. To explore biological plausibility, relevant results were inspected in search of expression quantitative trait loci (eQTLs) in two independent resources: BarcUVaSeq and the Genome Tissue Expression (GTEx) v8. Finally, we searched the Comparative Toxicogenomics Database to identify candidate genes previously linked to trihalomethane exposure, retrieved their eQTLs, and evaluated gene-environment interactions with TTHM levels. We found three variants that modulated CRC risk in relation to CHCl3 and TTHM exposure: rs77985109 near LRRC8B, chr15:28997737 near WHAMMP2, and rs7890183 near MAGEB2. Two additional variants were specifically found for women and one for rectal cancer. Functional assessment suggested a regulatory role of rs77985109 in LRRC8B expression. Moreover, eQTL analysis of candidate genes revealed an additional variant associated with CCL2 which could modulate CRC risk under different TTHM exposure levels. The present study identified novel loci potentially influencing CRC susceptibility under THM exposure, highlighting the importance of integrating environmental and genetic data to better understand environmental driven cancer risks. Further research is needed to confirm these results and clarify underlying mechanisms.
Reservoir computing in simulated neuronal cultures: Effectof network structure
(American Institute of Physics (AIP), 2026-02-17) Mats Houben, Akke; Haeb, Anna-Christina; García Ojalvo, Jordi; Soriano i Fradera, Jordi
Biological neurons are emerging as attractive candidates for artificial intelligence and machine learning applications given their natural energy efficiency and self-repair capacity. However, they differ from their idealized artificial counterparts. Biological neurons have highly variable and noisy dynamics and display intrinsic spontaneous activity instead of purely input-driven dynamics. Moreover, biological neuronal networks have physically constrained and highly plastic connections, leading to a complex and ever evolving connectivity structure. Here, we investigate (numerically and with preliminary experimental data) the stability of the input responses of neuronal cultures using a reservoir computing framework. Utilizing a numerical model for the growth and activity of neuronal cultures, previously used to model experimental data, we investigate the effect of large-scale network topology, specifically homogeneous vs modular architectures, on fading memory, reservoir performance under increasingly noisy dynamics, and robustness to network rewiring. We find that modular networks exhibit longer fading memory time, sustain higher performance under noisy conditions, and are more robust to connectivity rewiring than homogeneous networks. Finally, we observe no relationship between some characteristics of the network adjacency matrix (specifically its spectral properties) and reservoir computing performance.
Protocol for tailored in vitro neuronal networks on high-density microelectrode arrays with polydimethylsiloxane microstructures
(Elsevier B.V., 2026-03-20) Haeb, Anna-Christina; Yamamoto, Hideaki; Roach, Paul; Merryweather, Daniel; Sato, Y.; Tornero, Daniel; Soriano i Fradera, Jordi
Complementary metal-oxide-semiconductor (CMOS)-based high-density microelectrode arrays (HD-MEAs) enable neuronal recordings with high spatiotemporal resolution. However, integrating polydimethylsiloxane (PDMS) microstructures onto HD-MEA surfaces to control network architecture is currently challenging and platform specific. Here, we present a protocol for PDMS fabrication, HD-MEA chip preparation, PDMS-HD-MEA microstructure alignment, and cell culture, including alternatives. Our results show reproducible formation of modular networks with characteristic activity patterns across different systems. This protocol supports engineering of defined neuronal architectures while maintaining compatibility with various HD-MEA systems.
Unravel the rotational and translational behavior of a single squirmer in flexible polymer solutionsat diﬀerent Reynolds numbers
(Springer Nature, 2025-12-01) Qi, Kai; Zhou, H.Y.; Corato, Marco de; Stratford, Kevin; Pagonabarraga Mora, Ignacio
Microorganisms such as bacteria and algae navigate complex fluids, where their dynamics are vital for medical and industrial applications. However, the influence of the Reynolds number (Re) on the transport and rotational behavior of microswimmers in viscoelastic media remains poorly understood. Here, we investigate these effects for a model squirmer in flexible polymer solutions across a range of Re using Lattice Boltzmann simulations. The interaction between swimmer activity and polymer heterogeneity strongly affects behavior, with rotational enhancement up to 1400-fold and reduced self-propulsion and diffusivity for squirmers. These effects result from hydrodynamic and mechanical interactions: polymers wrap ahead of pushers and accumulate behind pullers, enhancing rotation while hindering translation through forces and torques from direct contacts or asymmetric flows. The influence of Re and squirmer-polymer boundary conditions (no-slip vs. repulsive) is also examined. Notably, no-slip conditions intensify effects above a critical Reynolds number (). Below this value, stronger viscous drag minimizes differences. Our findings emphasize the crucial role of polymer-swimmer interactions in shaping microswimmer behavior in viscoelastic media, informing microrobotic design in complex environments.
Multiscale Field Theory for Network Flows
(American Physical Society, 2025-05-07) Mikaberidze, Guram; Artime, Oriol; Díaz Guilera, Albert; D'Souza, Raissa M.
Network flows are pervasive, including the movement of people, transportation of goods, transmission of energy, and dissemination of information; they occur on a range of empirical interconnected systems, from designed infrastructure to naturally evolved networks. Despite the broad spectrum of applications, because of their domain-specific nature and the inherent analytic complexity, a comprehensive theory of network flows is lacking. We introduce a unifying treatment for network flows that considers the fundamental properties of packet symmetries, conservation laws, and routing strategies. For example, electrons in power grids possess interchangeability symmetry, unlike packages sent by postal mail, which are distinguishable. Likewise, packets can be conserved, such as cars in road networks, or dissipated, such as Internet packets that time out. We introduce a hierarchy of analytical field-theoretic approaches to capture the different scales of complexity required. Mean-field analysis uncovers the nature of the transition through which flow becomes unsustainable upon unchecked growth of demand. Mesoscopic field theory accurately accounts for complicated network structures, packet symmetries, and conservation laws and yet is capable of admitting closed-form solutions. Finally, the full-scale field theory allows us to study routing strategies ranging from random diffusion to shortest path. Our theoretical results indicate that flow bottlenecks tend to be near sources for interchangeable packets and near sinks for distinguishable ones, and that dissipation hinders the maximum sustainable throughput for interchangeable packets but can enhance throughput for distinguishable packets. Finally, we showcase the flexibility of our multiscale theory by applying it in two distinct domains of road networks and the C. elegans neuronal network. Our work paves the way for a more unifying and comprehensive theory of network flows.
Tunable dynamics of flexible magnetic microcrosses: synchronous rotation, breathing and out-of-plane arm overtaking
(Royal Society of Chemistry, 2025-10-13) Tavacoli, Joe; Stikuts, Andris P.; Dass, Mihir; Liedl, Tim; Tierno, Pietro
We combine colloidal self-assembly and soft-lithography techniques to realize flexible magnetic microcrosses that can be manipulated via external, time dependent magnetic fields. The crosses are characterized by a central domain connected via four flexible arms. When subjected to an in-plane, rotating magnetic field, the crosses transit from a synchronous to an asynchronous spinning motion where their average rotation decreases with the driving frequency. In the asynchronous regime and at low field amplitudes, the crosses display a breathing mode, characterized by relative oscillations between the arms, while remaining localized in the two dimensional plane. In contrast, for high field amplitudes, we observe an arm overtaking regime where two opposite filaments surpass the remaining ones forcing the cross to perform a three-dimensional gyroscopic-like rotation. Using slender body theory and balancing the effect of magnetic and elastic interactions, we recover the experimental findings and show that the overtaking regime occurs due to different arm magnetizations. Our engineered microscopic colloidal rotors characterized by multiple flexible filaments may find potential applications for precise lab-on-a-chip operations or as stirrers dispersed within microfluidic or biological channels.
Role of connectivity anisotropies in the dynamics of cultured neuronal networks
(Public Library of Science (PLoS), 2025-11-06) Houben, Akke Mats; García Ojalvo, Jordi; Soriano i Fradera, Jordi
An inherent challenge in designing laboratory-grown, engineered living neuronal networks lies in predicting the dynamic repertoire of the resulting network and its sensitivity to experimental variables. To fill this gap, and inspired by recent experimental studies, we present a numerical model designed to replicate the anisotropies in connectivity introduced through engineering, characterize the emergent collective behavior of the neuronal network, and make predictions. The numerical model is developed to replicate experimental data, and subsequently used to quantify network dynamics in relation to tunable structural and dynamical parameters. These include the strength of imprinted anisotropies, synaptic noise, and average axon lengths. We show that the model successfully captures the behavior of engineered neuronal cultures, revealing a rich repertoire of activity patterns that are highly sensitive to connectivity architecture and noise levels. Specifically, the imprinted anisotropies promote modularity and high clustering coefficients, substantially reducing the pathological-like bursting of standard neuronal cultures, whereas noise and axonal length influence the variability in dynamical states and activity propagation velocities. Moreover, connectivity anisotropies significantly enhance the ability to reconstruct structural connectivity from activity data, an aspect that is important to understand the structure–function relationship in neuronal networks. Our work provides a robust in silico framework to assist experimentalists in the design of in vitro neuronal systems and in anticipating their outcomes. This predictive capability is particularly valuable in developing reliable brain-on-a-chip platforms and in exploring fundamental aspects of neural computation, including input–output relationships and information coding.
Citizen Science initiatives in climate-vulnerable neighbourhoods: a new transdisciplinary approach to tackle sustainability challenges?
(Université Côte d'Azur, 2025-11-01) Bonhoure, Isabelle; Perelló, Josep, 1974-
According to the Spanish State Meteorological Agency (AEMET), the summer of 2025 (June 1-August 31) was exceptionally warm across Spain, with an average temperature of 24.2°C on the mainland. This value is 2.1°C above the seasonal average for the reference period 1991-2020. It was the warmest summer since records began in 1961, surpassing the previous record set in 2022 by 0.1°C . Barcelona and its metropolitan area, located along the Catalan coast, have been particularly affected by rising summer temperatures, a situation exacerbated by the urban heat island effect (Ward et al., 2016; Zhao et al., 2018). On 16 August 2025, a temperature of 38.9°C was recorded at the Fabra Observatory , one of the city's four official meteorological stations. This value exceeded the previous August record of 38.8°C, registered in 2023. Furthermore, according to an international study (Barnes et al., 2025), Barcelona reported the third-highest number of heat-related deaths among European cities during the summer of 2025, surpassed only by Milan and Rome.
Preparation and Mechano-Functional Characterization of PEGylated Fibrin Hydrogels: Impact of Thrombin Concentration
(2024-02-01) López-León, Clara F.; Planet Latorre, Ramon; Soriano i Fradera, Jordi
Three-dimensional (3D) neuronal cultures grown in hydrogels are promising platforms to design brain-like neuronal networks in vitro. However, the optimal properties of such cultures must be tuned to ensure a hydrogel matrix sufficiently porous to promote healthy development but also sufficiently rigid for structural support. Such an optimization is difficult since it implies the exploration of different hydrogel compositions and, at the same time, a functional analysis to validate neuronal culture viability. To advance in this quest, here we present a combination of a rheological protocol and a network-based functional analysis to investigate PEGylated fibrin hydrogel networks with gradually higher stiffness, achieved by increasing the concentration of thrombin. We observed that moderate thrombin concentrations of 10% and 25% in volume shaped healthy networks, although the functional traits depended on the hydrogel stiffness, which was much higher for the latter concentration. Thrombin concentrations of 65% or higher led to networks that did not survive. Our results illustrate the difficulties and limitations in preparing 3D neuronal networks, and stress the importance of combining a mechano-structural characterization of a biomaterial with a functional one.
Modular architecture confers robustness to damage and facilitates recovery in spikingneural networks modeling in vitro neurons
(Frontiers Media, 2025-06-19) Sumi, Takuma; Houben, Akke Mats; Yamamoto, Hideaki; Kato, Hideyuki; Katori, Yuichi; Soriano i Fradera, Jordi; Hirano-Iwata, Ayumi
Impaired brain function is restored following injury through dynamic processes that involve synaptic plasticity. This restoration is supported by the brain’s inherent modular organization, which promotes functional separation and redundancy. However, it remains unclear how modular structure interacts with synaptic plasticity to define damage response and recovery efficiency. In this work, we numerically modeled the response and recovery to damage of a neuronal network in vitro bearing a modular structure. The simulations aimed at capturing experimental observations in cultured neurons with modular traits which were physically disconnected through a focal lesion. The damage reduced the frequency of spontaneous collective activity events in the cultures, which recovered to pre-damage levels within 24 h. We rationalized this recovery in the numerical simulations by considering a plasticity mechanism based on spike-timing-dependent plasticity, a form of synaptic plasticity that modifies synaptic strength based on the relative timing of pre- and postsynaptic spikes. We observed that the in silico numerical model effectively captured the decline and subsequent recovery of spontaneous activity following the injury. The model supports that the combination of modularity and plasticity confers robustness to the damaged neuronal network by preventing the total loss of spontaneous network-wide activity and facilitating recovery. Additionally, by using our model within the reservoir computing framework, we show that information representation in the neuronal network improves with the recovery of network-wide activity.
Trends and drivers of pedestrian mobility in Barcelona: A fine-grained study across its commercial tissue
(Elsevier, 2025-03) Rames, Clément; Rhoads, Daniel; Meseguer Artola, Antoni; Lozano, Sergi; Borge Holthoefer, Javier; Solé Ribalta, Albert
Identifying factors that promote active mobility, especially walking, is essential for designing resilient and livable cities and promoting sustainable urban mobility. In spite of recent advances in this direction, available data often remains too spatially and temporally coarse, which constrains analysis. This paper leverages high resolution data from over 200 pedestrian count sensors, placed along Barcelona’s commercial areas, providing a detailed understanding of how walking volume has evolved over the past five years, how it varies across neighborhoods, and which socioeconomic and urban attributes influence it. We find that while overall pedestrian traffic has increased, a neighborhood-scale analysis reveals a nuanced picture of fluctuations, including increases, declines, and periodic patterns. The use of global regression models allows us to identify seven key urban factors that shape pedestrian mobility. Subsequently moving the analysis to spatially-aware regression models, we identify the spatial non-stationarity of these factors across the city, indicating the presence of distinct behavioral groups within the urban population. The detailed spatial resolution of our findings provides municipal decision-makers with insights for implementing precise interventions and continually evaluating their effects. Moreover, monitoring pedestrian traffic before and after urban initiatives, while adjusting for seasonal, daily, and time-of-day variations, can yield critical insights for developing pedestrian-oriented urban environments.
Long-term exposure to nitrate and trihalomethanes in drinking water and gastric cancer: A multicase–control study in Spain (MCC-Spain)
(National Institute of Environmental Health Science, 2025-04-15) Donat Vargas, Carolina; Kogevinas, Manolis; Castaño-Vinyals, Gemma; Pérez Gómez, Beatriz; Aragonès Sanz, Núria; Guevara, Marcela; Gómez Acebo, Inés; Molina, Antonio; Fernandez-Tardon, Guillermo; Vanaclocha Espi, Mercedes; Molina Barceló, Ana; Moreno Aguado, Víctor; Pollán, Marina; Villanueva, Cristina M.
Background: Disinfection byproducts and N-nitroso compounds (NOC) formed endogenously after nitrate ingestion have been shown to be carcinogenic in animal studies, but epidemiological evidence is limited, especially in relation to gastric cancer. Objective: We evaluated the association between drinking water exposure to nitrate and trihalomethanes (THMs) and gastric cancer in a multicase–control study conducted in Spain (MCC-Spain). Methods: In 2008–2013, 254 hospital-based incident gastric cancer cases and 2,365 population-based controls were recruited, providing information on residential histories and type of water consumed. Adult lifetime average nitrate and THM levels in residences from age 18 until 2 years before the interview were estimated and linked with water consumption information to calculate waterborne ingested nitrate, brominated (Br)-THMs, and chloroform. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression, with adjustment for potential confounders. We assessed the effect modification by factors influencing endogenous NOC formation. Results: Median [percentile 25th (P25)–percentile 75 (P75)] (P25–P75) lifetime waterborne ingested nitrate (mg/day), Br-THMs (μ⁢g/day), and chloroform (μ⁢g/day) were 2.7 (1.4–5.6), 3.8 (1.5–8.1), and 12.2 (4.0–23.7), respectively, in cases and 3.8 (1.8–8.5), 5.7 (2.6–19.2), and 12.9 (4.6–24.5) in controls, respectively. Adjusted OR (95% CI) for gastric cancer comparing nitrate intake >9.7 vs. ≤9.7mg/day (percentile 80th, P80) was 1.42 (0.88, 2.29). This association was more pronounced among participants with low consumption of vegetables [2.24 (1.02, 4.91)], vitamin C [2.10 (0.94, 4.71)], and vitamin E [2.81 (1.16, 6.78)] and among those with high consumption of alcohol [2.78 (0.98, 7.93)] or processed meat [1.91 (0.97, 3.75)]. When stratified by age, the association only remained in the >65 years of age group (median 73 years of age). OR for gastric cancer comparing Br-THM ingestion ≥vs.80th<80th percentile was 0.65 (0.33, 1.28) and for chloroform was 1.36 (0.87, 2.14). Comparable ORs were found for residential concentrations. Conclusions: Long-term waterborne nitrate exposure below regulatory limits may increase gastric cancer risk among older adults and in those with poor dietary patterns. These findings need to be confirmed by cohort studies with larger sample sizes.
Multicaloric effects and magnetostructural coupling in the Cr2Ge2Te6 van der Waals crystal
(Elsevier, 2025-04-22) Abadia-Huguet, Aleix; Mendive Tapia, Eduardo; Stern Taulats, Enric; Planes Vila, Antoni; Eggert, Benedikt; Wende, Heiko; Acet, Mehmet; Sturza, Mihai-Ionut; Kohlmann, Holger; Costache, Marius V.; Mañosa, Lluís
Materials with significant coupling between magnetism and their crystal structure are prone to exhibit multicaloric effects, which offer a novel approach to addressing the bottlenecks of ecologic solid-state refrigeration by optimizing the interplay of multiple driving fields. Here we uncover the multicaloric properties of CrGeTe, establishing ferromagnetic van der Waals (vdW) crystals, famous for their spintronics applications, as a previously unrecognized class of multicaloric materials. By combining magnetization measurements with an ab initio disordered local moment theory, we report, for the first time, pronounced barocaloric and multicaloric effects induced by the application of magnetic fields and hydrostatic pressure around CrGeTe’s ferromagnetic phase transition. Our experimental and ab initio analysis quantifies the underlying magnetostructural coupling in this material, which accounts for approximately 25% of the total multicaloric entropy change. Significant multicaloric effects are expected to be found in other vdW ferromagnets with strong magnetostructural coupling.
First Order Alignment Transition in an Interfaced Active Nematic
(American Physical Society, 2024-06-15) Bantysh, Olga; Martinez-Prat, Berta; Nambisan, Jyothishraj; Fernández-Nieves, Alberto; Sagués i Mestre, Francesc; Ignés i Mullol, Jordi
We investigate experimentally the dynamic phase transition of a two-dimensional active nematic layer interfaced with a passive liquid crystal. Under a temperature ramp that leads to the transition of the passive liquid into a highly anisotropic lamellar smectic-A phase, and in the presence of a magnetic field, the coupled active nematic reorganizes its flow and orientational patterns from the turbulent into a quasilaminar regime aligned perpendicularly to the field. Remarkably, while the phase transition of the passive fluid is known to be continuous, or second order, our observations reveal intermittent dynamics of the order parameter and the coexistence of aligned and turbulent regions in the active nematic, a signature of discontinuous, or first order, phase transitions, similar to what is known to occur in relation to flocking in dry active matter. Our results suggest that alignment transitions in active systems are intrinsically discontinuous, regardless of the symmetry and momentum-damping mechanisms.
Discounting the Distant Future: What Do Historical Bond Prices Imply about the Long-Term Discount Rate?
(MDPI, 2024-03-01) Farmer, J. Doyne; Geanakoplos, John; Richiardi, Matteo G.; Montero Matellanes, M. Mikel; Perelló, Josep, 1974-; Masoliver, Jaume, 1951-
We present a thorough empirical study on real interest rates by also including risk aversion through the introduction of the market price of risk. From the viewpoint of complex systems science and its multidisciplinary approach, we use the theory of bond pricing to study the long-term discount rate to estimate the rate when taking historical US and UK data, and to further contribute to the discussion about the urgency of climate action in the context of environmental economics and stochastic methods. Century-long historical records of 3-month bonds, 10-year bonds, and inflation allow us to estimate real interest rates for the UK and the US. Real interest rates are negative about a third of the time and the real yield curves are inverted more than a third of the time, sometimes by substantial amounts. This rules out most of the standard bond-pricing models, which are designed for nominal rates that are assumed to be positive. We, therefore, use the Ornstein–Uhlenbeck model, which allows negative rates and gives a good match to inversions of the yield curve. We derive the discount function using the method of Fourier transforms and fit it to the historical data. The estimated long-term discount rate is 1.7% for the UK and 2.2% for the US. The value of 1.4% used by Stern is less than a standard deviation from our estimated long-run return rate for the UK, and less than two standard deviations of the estimated value for the US. All of this once more reinforces the need for immediate and substantial spending to combat climate change.

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