Browse Articles

Global decline of apex scavengers threatens human health

Vertebrate scavengers play a critical role in ecosystem functioning worldwide. Through the cascading effects of their ecological role, scavengers can also alleviate the burden of zoonotic diseases on people. This importance to human health fuels a growing need to understand how vertebrate scavengers and their ecosystem services are faring globally in the Anthropocene. We reviewed the conservation status of 1,376 vertebrate scavenging species and examined the implications for human health. We uncovered that 36% of these species are threatened or decreasing in population abundance and that apex (large-bodied or obligate) scavengers are disproportionately imperiled. In contrast, mesoscavengers (small-bodied or facultative) are thriving from anthropogenic food subsidies and ecological release. We posit that this global shift in scavenger community structure increases carrion persistence enabling zoonotic pathogens to propagate. Our analysis also indicates that the release of mesoscavengers is associated with reservoir host proliferation, potentially further exacerbating human disease burdens. Urgently tackling the key threats to scavengers—intensive livestock production, land use change, wildlife trade, and the interactions among them—is critical to securing the long-term public health benefits of the world’s diverse scavenger communities.

Caveolin invasion of lipid territory

Humanized mice to model rare human diseases

Abrupt shift of El Niño periodicity under CO ₂ mitigation

Removing CO 2 from the atmosphere is emerging as a viable strategy to mitigate global warming, yet the responses of the climate system to CO 2 reduction remain uncertain. One of the most uncertain aspects of El Niño behavior is the change in periodicity in response to CO 2 forcing [O. Alizadeh, Earth-Sci. Rev. 235 , 104246 (2022)]. In this study, we show that climate models consistently project an abrupt shortening of El Niño periodicity once CO 2 reductions commence in ramp-up and ramp-down CO 2 experiments. Besides the contribution of slow mean state changes, this phenomenon is shown to be driven by a southward shift of the Intertropical Convergence Zone (ITCZ) [J.-S. Kug, et al. , Nat. Clim. Chang. 12 , 47–53 (2022)] and the consequent narrowing of El Niño’s spatial pattern, which enhances the effectiveness of ocean heat recharge/discharge processes, thereby shortening its periodicity. This suggests that the abrupt shift in El Niño periodicity results from a cascading reaction involving ITCZ dynamics and El Niño’s spatial configuration. These findings highlight the critical role of the global energy balance in shaping El Niño characteristics.

Human influence on climate detectable in the late 19th century

The physics of the heat-trapping properties of CO 2 were established in the mid-19th century, as fossil fuel burning rapidly increased atmospheric CO 2 levels. To date, however, research has not probed when climate change could have been detected if scientists in the 19th century had the current models and observing network. We consider this question in a thought experiment with state-of-the-art climate models. We assume that the capability to make accurate measurements of atmospheric temperature changes existed in 1860, and then apply a standard “fingerprint” method to determine the time at which a human-caused climate change signal was first detectable. Pronounced cooling of the mid- to upper stratosphere, mainly driven by anthropogenic increases in carbon dioxide, would have been identifiable with high confidence by approximately 1885, before the advent of gas-powered cars. These results arise from the favorable signal-to-noise characteristics of the mid- to upper stratosphere, where the signal of human-caused cooling is large and the pattern of this cooling differs markedly from patterns of intrinsic variability. Even if our monitoring capability in 1860 had not been global, and high-quality stratospheric temperature measurements existed for Northern Hemisphere mid-latitudes only, it still would have been feasible to detect human-caused stratospheric cooling by 1894, only 34 y after the assumed start of climate monitoring. Our study provides strong evidence that a discernible human influence on atmospheric temperature has likely existed for over 130 y.

Increased frequency of planetary wave resonance events over the past half-century

We demonstrate a tripling in the frequency of planetary wave resonance events over the past halfcentury, coinciding with the rise in persistent boreal summer weather extremes. This increase aligns with changes in the underlying climate conditions favoring these events, including amplified Arctic warming and land–sea thermal contrast. We also observe increased prevalence of resonant amplification events following the mature phase of strong El Niño events, suggesting that such events may precondition the mean state conditions in ways that favor large-scale quasi-stationary wave patterns and quasi-resonant wave amplification. Since the impact of anthropogenic warming on quasi-resonant amplification is not well captured by current-generation climate models, it is likely that models are underpredicting the potential increase, indicating even greater risk of persistent extreme summer weather events with ongoing warming.

Humans program artificial delegates to accurately solve collective-risk dilemmas but lack precision

In an era increasingly influenced by autonomous machines, it is only a matter of time before strategic individual decisions that impact collective goods will also be made virtually through the use of artificial delegates. Through a series of behavioral experiments that combine delegation to autonomous agents and different choice architectures, we pinpoint what may get lost in translation when humans delegate to algorithms. We focus on the collective-risk dilemma, a game where participants must decide whether or not to contribute to a public good, where the latter must reach a target in order for them to keep their personal endowments. To test the effect of delegation beyond its functionality as a commitment device, participants are asked to play the game a second time, with the same group, where they are given the chance to reprogram their agents. As our main result we find that, when the action space is constrained, people who delegate contribute more to the public good, even if they have experienced more failure and inequality than people who do not delegate. However, they are not more successful. Failing to reach the target, after getting close to it, can be attributed to precision errors in the agent’s algorithm that cannot be corrected amid the game. Thus, with the digitization and subsequent limitation of our interactions, artificial delegates appear to be a solution to help preserving public goods over many iterations of risky situations. But actual success can only be achieved if humans learn to adjust their agents’ algorithms.

Monocytes use protrusive forces to generate migration paths in viscoelastic collagen-based extracellular matrices

Circulating monocytes are recruited to the tumor microenvironment, where they can differentiate into macrophages that mediate tumor progression. To reach the tumor microenvironment, monocytes must first extravasate and migrate through the type-1 collagen rich stromal matrix. The viscoelastic stromal matrix around tumors not only stiffens relative to normal stromal matrix, but often exhibits enhanced viscous characteristics, as indicated by a higher loss tangent or faster stress relaxation rate. Here, we studied how changes in matrix stiffness and viscoelasticity impact the three-dimensional (3D) migration of monocytes through stromal-like matrices. Interpenetrating networks of type-1 collagen and alginate, which enable independent tunability of stiffness and stress relaxation over physiologically relevant ranges, were used as confining matrices for 3D culture of monocytes. Increased stiffness and faster stress relaxation independently enhanced the 3D migration of monocytes. Migrating monocytes have an ellipsoidal or rounded wedge-like morphology, reminiscent of amoeboid migration, with accumulation of actin at the trailing edge. Matrix adhesions were dispensable for monocyte migration in 3D, but migration did require actin polymerization and myosin contractility. Mechanistic studies indicate that actin polymerization at the leading edge generates protrusive forces that open a path for the monocytes to migrate through in the confining viscoelastic matrices. Taken together, our findings implicate matrix stiffness and stress relaxation as key mediators of monocyte migration and reveal how monocytes use pushing forces at the leading edge mediated by actin polymerization to generate migration paths in confining viscoelastic matrices.

Siderite and ferric oxyhydroxides imply interlinked carbon, iron, and halogen cycles on Mars

Pure siderite [Fe II CO 3 ] was recently discovered in abundant quantities (4.8 to 10.5 wt.%) by the Curiosity rover at Gale crater, Mars. Diagenetic alteration of siderite likely caused the carbonate-sequestered CO 2 to be released back into the atmosphere and consequently produced ferric [Fe(III)] oxyhydr(oxide) minerals. Here, using laboratory experimentation, we demonstrate that while closed system acid diagenesis—as proposed for Gale crater—is incapable of effective siderite alteration in Mars-relevant fluids, oxyhalogen compounds (chlorate and bromate) can weather siderite not only at acidic pH but also in near-neutral Mars-relevant solutions. The ferric oxyhydroxide minerals produced as a consequence are controlled by the diagenetic fluid composition. While photooxidation is possible, the mutually exclusive products of alteration—magnetite (Fe 3 O 4 ) during ultraviolet irradiation and ferric oxyhydroxide (FeOOH) by oxyhalogens—demonstrate that siderite at Gale crater underwent chemical weathering by chlorate and bromate brines owing to the complete absence of magnetite in drill samples containing siderite. We propose a top–down oxyhalogen brine percolation model to explain the iron mineralogy of the sulfate-rich unit at Gale crater. We conclude that siderite alteration by acidic fluids alone cannot explain the redox disequilibrium witnessed in Gale crater sediments as promulgated before and siderite weathering by oxyhalogen brines is the most likely explanation. It is highly likely that the halogen cycle on Mars is interlinked to the iron and the carbon cycle on early and current Mars.

Collective cooperative intelligence

Cooperation at scale is critical for achieving a sustainable future for humanity. However, achieving collective, cooperative behavior—in which intelligent actors in complex environments jointly improve their well-being—remains poorly understood. Complex systems science (CSS) provides a rich understanding of collective phenomena, the evolution of cooperation, and the institutions that can sustain both. Yet, much of the theory in this area fails to fully consider individual-level complexity and environmental context—largely for the sake of tractability and because it has not been clear how to do so rigorously. These elements are well captured in multiagent reinforcement learning (MARL), which has recently put focus on cooperative (artificial) intelligence. However, typical MARL simulations can be computationally expensive and challenging to interpret. In this perspective, we propose that bridging CSS and MARL affords new directions forward. Both fields can complement each other in their goals, methods, and scope. MARL offers CSS concrete ways to formalize cognitive processes in dynamic environments. CSS offers MARL improved qualitative insight into emergent collective phenomena. We see this approach as providing the necessary foundations for a proper science of collective, cooperative intelligence. We highlight work that is already heading in this direction and discuss concrete steps for future research.

Correction for Manthey et al., Rapid growth and the evolution of complete metamorphosis in insects

Reply to Uveges et al.: The assumption of a time-constant emission factor leads to biased estimates of fossil fuel methane emissions

Correction for Jiang et al., Structural basis of the cysteinyl leukotriene receptor type 2 activation by LTD4

Correction for Borovska and de Haas, Individual gaze shapes diverging neural representations

Correction for Yang et al., Synonymous edits in the <i>Escherichia coli</i> genome have substantial and condition-dependent effects on fitness

The VIPR-1 trial (Visualizing Ischemia in the Pancreatic Remnant): Assessing the role of intraoperative indocyanine green perfusion in predicting postoperative pancreatic leaks and fistulas: Protocol for a phase II clinical trial

Surgery of the pancreas has come a long way since its inception; however, postoperative morbidity is still high. Pancreatic leaks and fistulas are common complications in patients undergoing surgery to remove the pancreas. Fistulas delay subsequent oncological care after surgery and prolong the hospital stay. Hypoperfusion of the pancreas has been proposed as one factor leading to fistulas. Indocyanine green (ICG) injection allows the surgeon to evaluate blood perfusion to tissue in real-time. This protocol describes a trial that aims to assess the effectiveness of intraoperative ICG metrics of the cut edge of the remnant pancreas to predict postoperative fistulas. A single group will participate in an observational, surgeon-blinded, phase II trial. ICG measurements of the cut edge of the pancreas will be recorded before reconstruction. International Study Group on Pancreatic Surgery criteria for pancreatic fistula will be used to define leaks and fistulas. The study objective is to analyze the correlation between ICG measurements and the development or absence of both biochemical leak and clinically relevant fistula formation. Currently, limited objective intraoperative predictors exist for predicting postoperative fistulas. Having a reliable predictive tool could decrease the healthcare burden posed by fistulas. The findings of this trial will provide conclusions on the usefulness of ICG measurements in predicting postoperative pancreatic fistulas and leaks. This clinical trial is registered in ClinicalTrials.gov with the ID NCT06084013. The current protocol version is v1.1.

Identification and mitigation of blood’s interference with the antimicrobial activity of AgNbO3 particles

The detrimental impact of blood on the antimicrobial activity of AgNbO3 particles was identified and investigated. It was observed that the impact is more severe in the case of lysed blood. The same phenomenon also operates in the case of commonly used silver salt, AgNO3. The inhibition was shown to be due to hemoglobin, but may be unrelated to the heme moiety. In an attempt to find additives to mitigate the inhibitory effect of hemoglobin, iron ions and the chelating agent, K2EDTA, were initially considered as potential candidates. Including ferric iron on the particles was shown to have a marginal effect, but supplying the medium with K2EDTA chelating agent, provided a better outcome for countering the deleterious impact of hemoglobin on AgNbO3 activity. These findings may be relevant for adapting the silver compounds to applications such as wound dressings, where silver’s antimicrobial action would have to take place in a blood containing environment.

The relationship between fibular head height and lower limb alignment deviation and severity after TKA for varus deformity knee osteoarthritis

Purpose To investigate the correlation between fibular head height and the deviation and severity of lower limb alignment after TKA in patients with varus deformity and knee osteoarthritis. Methods Based on the varus angle (γ = 10°), the sample was divided into two groups: &lt; 10° and ≥10°, The differences in fibular head height between the two groups of patients were analyzed using an independent samples t-test; The Mann-Whitney test was used to analyze the differences in fibular head height between genders. An unordered multinomial logistic regression analysis was conducted to evaluate the effects of age, gender, height, weight, body mass index, and fibular head height on postoperative lower limb alignment; Pearson correlation analysis was used to assess the correlation between fibular head height and varus angle, preoperative HKA angle, and postoperative HKA angle; A Multiple linear regression was performed to evaluate the effects of gender, age, height, weight, body mass index, fibular head height, preoperative HKA angle, and varus angle on the postoperative HKA angle. Results The sample was divided into two groups based on the varus angle: ≥ 10° and &lt;10°. The fibular head height was 8.1825 ± 2.72505 mm in one group and 9.2234 ± 2.68225 mm in the other group (p = 0.028 &lt; 0.05), which was statistically significant; The median fibular head height in females was 8.050 mm, compared to 10.645 mm in males (p &lt; 0.05), which was statistically significant. In the unordered multinomial logistic regression, with postoperative lower limb alignment (varus, valgus, neutral) as the dependent variable, In the unordered multinomial logistic regression with postoperative lower limb alignment as the dependent variable, Height, weight, and body mass index are influencing factors for postoperative lower limb alignment in patients with varus deformity knee osteoarthritis, affecting both varus and valgus alignment, while fibular head height is a significant factor for postoperative varus alignment. In the Pearson correlation analysis, fibular head height was positively correlated with postoperative HKA angle (r = 0.212, p &lt; 0.05). In the multiple linear regression with postoperative HKA angle as the dependent variable, fibular head height and preoperative HKA angle were identified as significant factors influencing the postoperative HKA angle (p &lt; 0.05). Conclusions This study found that in patients with varus deformity knee osteoarthritis, a greater degree of varus was associated with a lower fibular head height. Additionally, the fibular head in female patients was positioned closer to the lateral tibial plateau compared to male patients. In varus deformity knee osteoarthritis, fibular head height is a risk factor for postoperative lower limb varus alignment following total knee arthroplasty (TKA). Patients with a higher-positioned fibular head (lower fibular head height) are more likely to develop postoperative varus malalignment after TKA. Therefore, routine measurement of fibular head height is warranted in clinical practice for patients with varus deformity knee osteoarthritis.

Correction for Luo and Yu, NBS1 facilitates preribosomal RNA biogenesis

Synergistic application of artificial intelligence and response surface methodology for predicting and enhancing in vitro tuber production of potato (Solanum tuberosum)

In vitro regeneration of potato tubers is highly significant in modern agriculture as it offers efficient propagation, genetic enhancement, and pathogen-free seed production. This study aimed to optimize in vitro tuberization by manipulating key variables, including cultivar, sucrose concentration, and cytokinin-auxin interactions. Results were analyzed by response surface regression analysis (RSRA) of Response Surface Methodology (RSM), followed by data validation and prediction with machine learning (ML) models. Fontana cultivar exhibited superior tuberization performance, with a maximum tuberization rate of 75.6% from Murashige and Skoog (MS) medium supplemented with 90 g/L sucrose, 2 mg/L BAP, and 1 mg/L Indole-3-butyric acid (IBA). Sucrose concentration was the most significant factor for all growth parameters, particularly tuber size and weight. RSRA analysis confirmed the significance of the linear effects of sucrose and BAP on tuberization, while auxins primarily regulated tuber size and weight. Pareto chart analysis highlighted sucrose as the most influential variable for both cultivars. Heatmap and network plot analyses further illustrated strong positive correlations between sucrose, BAP, and tuber formation, whereas auxins exhibited comparatively weaker effects. Results analyzed by Machine learning (ML) models revealed maximum predictive accuracy for tuberization by Random Forest (RF) model with an R2 of 0.379. However, all other models also faced challenges with high error rates, indicating the need for improved feature engineering. This study concludes that optimizing sucrose concentration and BAP levels, combined with selective auxin application, and integration of RSM and AI presents a promising strategy for optimization and potentially improving large-scale commercial production of disease-free potato tubers.