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Norm enforcement may be important for resolving conflicts and promoting cooperation. However, little is known about how preferred responses to norm violations vary across cultures and across domains. In a preregistered study of 57 countries (using convenience samples of 22,863 students and non-students), we measured perceptions of the appropriateness of various responses to a violation of a cooperative norm and to atypical social behaviors. Our findings highlight both cultural universals and cultural variation. We find a universal negative relation between appropriateness ratings of norm violations and appropriateness ratings of responses in the form of confrontation, social ostracism and gossip. Moreover, we find the country variation in the appropriateness of sanctions to be consistent across different norm violations but not across different sanctions. Specifically, in those countries where use of physical confrontation and social ostracism is rated as less appropriate, gossip is rated as more appropriate. Little is known about people’s preferred responses to norm violations across countries. Here, in a study of 57 countries, the authors highlight cultural similarities and differences in people’s perception of the appropriateness of norm violations.

Mechanical metamaterials enable the creation of structural materials with unprecedented mechanical properties. However, thus far, research on mechanical metamaterials has focused on passive mechanical metamaterials and the tunability of their mechanical properties. Deep integration of multifunctionality, sensing, electrical actuation, information processing, and advancing data-driven designs are grand challenges in the mechanical metamaterials community that could lead to truly intelligent mechanical metamaterials. In this perspective, we provide an overview of mechanical metamaterials within and beyond their classical mechanical functionalities. We discuss various aspects of data-driven approaches for inverse design and optimization of multifunctional mechanical metamaterials. Our aim is to provide new roadmaps for design and discovery of next-generation active and responsive mechanical metamaterials that can interact with the surrounding environment and adapt to various conditions while inheriting all outstanding mechanical features of classical mechanical metamaterials. Next, we deliberate the emerging mechanical metamaterials with specific functionalities to design informative and scientific intelligent devices. We highlight open challenges ahead of mechanical metamaterial systems at the component and integration levels and their transition into the domain of application beyond their mechanical capabilities. Mechanical metamaterials are known for their unconventional mechanical properties. In this perspective, the authors give an overview of the current state of mechanical materials research and suggest a roadmap for next-generation active and responsive mechanical metamaterials.

The novelty of this article lies in introducing a novel stochastic technique named the Hippopotamus Optimization (HO) algorithm. The HO is conceived by drawing inspiration from the inherent behaviors observed in hippopotamuses, showcasing an innovative approach in metaheuristic methodology. The HO is conceptually defined using a trinary-phase model that incorporates their position updating in rivers or ponds, defensive strategies against predators, and evasion methods, which are mathematically formulated. It attained the top rank in 115 out of 161 benchmark functions in finding optimal value, encompassing unimodal and high-dimensional multimodal functions, fixed-dimensional multimodal functions, as well as the CEC 2019 test suite and CEC 2014 test suite dimensions of 10, 30, 50, and 100 and Zigzag Pattern benchmark functions, this suggests that the HO demonstrates a noteworthy proficiency in both exploitation and exploration. Moreover, it effectively balances exploration and exploitation, supporting the search process. In light of the results from addressing four distinct engineering design challenges, the HO has effectively achieved the most efficient resolution while concurrently upholding adherence to the designated constraints. The performance evaluation of the HO algorithm encompasses various aspects, including a comparison with WOA, GWO, SSA, PSO, SCA, FA, GOA, TLBO, MFO, and IWO recognized as the most extensively researched metaheuristics, AOA as recently developed algorithms, and CMA-ES as high-performance optimizers acknowledged for their success in the IEEE CEC competition. According to the statistical post hoc analysis, the HO algorithm is determined to be significantly superior to the investigated algorithms. The source codes of the HO algorithm are publicly available at https://www.mathworks.com/matlabcentral/fileexchange/160088-hippopotamus-optimization-algorithm-ho .

For capacitive energy storage at elevated temperatures 1 – 4 , dielectric polymers are required to integrate low electrical conduction with high thermal conductivity. The coexistence of these seemingly contradictory properties remains a persistent challenge for existing polymers. We describe here a class of ladderphane copolymers exhibiting more than one order of magnitude lower electrical conductivity than the existing polymers at high electric fields and elevated temperatures. Consequently, the ladderphane copolymer possesses a discharged energy density of 5.34 J cm −3 with a charge–discharge efficiency of 90% at 200 °C, outperforming the existing dielectric polymers and composites. The ladderphane copolymers self-assemble into highly ordered arrays by π–π stacking interactions 5 , 6 , thus giving rise to an intrinsic through-plane thermal conductivity of 1.96 ± 0.06 W m −1  K −1 . The high thermal conductivity of the copolymer film permits efficient Joule heat dissipation and, accordingly, excellent cyclic stability at elevated temperatures and high electric fields. The demonstration of the breakdown self-healing ability of the copolymer further suggests the promise of the ladderphane structures for high-energy-density polymer capacitors operating under extreme conditions. A class of dielectric copolymers called ladderphanes is shown to outperform existing dielectric polymers and composites, with high discharged energy density and charge–discharge efficiency even at temperatures up to 200 °C.

Tissues are dynamically shaped by bidirectional communication between resident cells and the extracellular matrix (ECM) through cell-matrix interactions and ECM remodelling. Tumours leverage ECM remodelling to create a microenvironment that promotes tumourigenesis and metastasis. In this review, we focus on how tumour and tumour-associated stromal cells deposit, biochemically and biophysically modify, and degrade tumour-associated ECM. These tumour-driven changes support tumour growth, increase migration of tumour cells, and remodel the ECM in distant organs to allow for metastatic progression. A better understanding of the underlying mechanisms of tumourigenic ECM remodelling is crucial for developing therapeutic treatments for patients. Tumors are more than cancer cells — the extracellular matrix is a protein structure that organizes all tissues and is altered in cancer. Here, the authors review recent progress in understanding how the cancer cells and tumor-associated stroma cells remodel the extracellular matrix to drive tumor growth and metastasis.

In the quest for environmental sustainability, the rising demand for electric vehicles and renewable energy technologies has substantially increased the need for efficient lithium extraction methods. Traditional lithium production, relying on geographically concentrated hard-rock ores and salar brines, is associated with considerable energy consumption, greenhouse gas emissions, groundwater depletion and land disturbance, thereby posing notable environmental and supply chain challenges. On the other hand, low-quality brines—such as those found in sedimentary waters, geothermal fluids, oilfield-produced waters, seawater and some salar brines and salt lakes—hold large potential owing to their extensive reserves and widespread geographical distribution. However, extracting lithium from these sources presents technical challenges owing to low lithium concentrations and high magnesium-to-lithium ratios. This Review explores the latest advances and continuing challenges in lithium extraction from these demanding yet promising sources, covering a variety of methods, including precipitation, solvent extraction, sorption, membrane-based separation and electrochemical-based separation. Furthermore, we share perspectives on the future development of lithium extraction technologies, framed within the basic principles of separation processes. The aim is to encourage the development of innovative extraction methods capable of making use of the substantial potential of low-quality brines. Precipitation, solvent extraction, sorption, membrane-based separation and electrochemical-based separation are described as promising methods for extracting lithium from low-quality brines, which have extensive reserves and widespread geographical distributions.

The ice arches that usually develop at the northern and southern ends of Nares Strait play an important role in modulating the export of Arctic Ocean multi-year sea ice. The Arctic Ocean is evolving towards an ice pack that is younger, thinner, and more mobile and the fate of its multi-year ice is becoming of increasing interest. Here, we use sea ice motion retrievals from Sentinel-1 imagery to report on the recent behavior of these ice arches and the associated ice fluxes. We show that the duration of arch formation has decreased over the past 20 years, while the ice area and volume fluxes along Nares Strait have both increased. These results suggest that a transition is underway towards a state where the formation of these arches will become atypical with a concomitant increase in the export of multi-year ice accelerating the transition towards a younger and thinner Arctic ice pack. Ice arches that form along Nares Strait, which separates Greenland and Ellesmere Island, act to reduce the export of thick multi-year ice out of the Arctic. Here, we show that there has been a recent trend towards shorter duration arch formation that has resulted in enhanced transport of ice along the strait.

Carbon dioxide (CO 2 ) is a key chemical species that is found in a wide range of planetary atmospheres. In the context of exoplanets, CO 2 is an indicator of the metal enrichment (that is, elements heavier than helium, also called ‘metallicity’) 1 – 3 , and thus the formation processes of the primary atmospheres of hot gas giants 4 – 6 . It is also one of the most promising species to detect in the secondary atmospheres of terrestrial exoplanets 7 – 9 . Previous photometric measurements of transiting planets with the Spitzer Space Telescope have given hints of the presence of CO 2 , but have not yielded definitive detections owing to the lack of unambiguous spectroscopic identification 10 – 12 . Here we present the detection of CO 2 in the atmosphere of the gas giant exoplanet WASP-39b from transmission spectroscopy observations obtained with JWST as part of the Early Release Science programme 13 , 14 . The data used in this study span 3.0–5.5 micrometres in wavelength and show a prominent CO 2 absorption feature at 4.3 micrometres (26-sigma significance). The overall spectrum is well matched by one-dimensional, ten-times solar metallicity models that assume radiative–convective–thermochemical equilibrium and have moderate cloud opacity. These models predict that the atmosphere should have water, carbon monoxide and hydrogen sulfide in addition to CO 2 , but little methane. Furthermore, we also tentatively detect a small absorption feature near 4.0 micrometres that is not reproduced by these models. Transmission spectroscopy observations from the James Webb Space Telescope show the detection of carbon dioxide in the atmosphere of the gas giant exoplanet WASP-39b.

Clinicians and software developers need to understand how proposed machine learning (ML) models could improve patient care. No single metric captures all the desirable properties of a model, which is why several metrics are typically reported to summarize a model’s performance. Unfortunately, these measures are not easily understandable by many clinicians. Moreover, comparison of models across studies in an objective manner is challenging, and no tool exists to compare models using the same performance metrics. This paper looks at previous ML studies done in gastroenterology, provides an explanation of what different metrics mean in the context of binary classification in the presented studies, and gives a thorough explanation of how different metrics should be interpreted. We also release an open source web-based tool that may be used to aid in calculating the most relevant metrics presented in this paper so that other researchers and clinicians may easily incorporate them into their research.

Glaciers are indicators of ongoing anthropogenic climate change 1 . Their melting leads to increased local geohazards 2 , and impacts marine 3 and terrestrial 4 , 5 ecosystems, regional freshwater resources 6 , and both global water and energy cycles 7 , 8 . Together with the Greenland and Antarctic ice sheets, glaciers are essential drivers of present 9 , 10 and future 11 , 12 – 13 sea-level rise. Previous assessments of global glacier mass changes have been hampered by spatial and temporal limitations and the heterogeneity of existing data series 14 , 15 – 16 . Here we show in an intercomparison exercise that glaciers worldwide lost 273 ± 16 gigatonnes in mass annually from 2000 to 2023, with an increase of 36 ± 10% from the first (2000–2011) to the second (2012–2023) half of the period. Since 2000, glaciers have lost between 2% and 39% of their ice regionally and about 5% globally. Glacier mass loss is about 18% larger than the loss from the Greenland Ice Sheet and more than twice that from the Antarctic Ice Sheet 17 . Our results arise from a scientific community effort to collect, homogenize, combine and analyse glacier mass changes from in situ and remote-sensing observations. Although our estimates are in agreement with findings from previous assessments 14 , 15 – 16 at a global scale, we found some large regional deviations owing to systematic differences among observation methods. Our results provide a refined baseline for better understanding observational differences and for calibrating model ensembles 12 , 16 , 18 , which will help to narrow projection uncertainty for the twenty-first century 11 , 12 , 18 . An intercomparison exercise reassesses mass loss from glaciers worldwide based on the main in situ and satellite methods from 2000 to 2023; the results are consistent with previous assessments and provide a refined and comprehensive observational baseline for future impact and modelling studies.