PNAS nexus最新文献_第4页

Warming accelerates drought-flood oscillations and stratifies socioeconomic exposure. 变暖加速了旱涝振荡，并使社会经济风险分层。

IF 4.8

PNAS nexus Pub Date : 2026-09-15 eCollection Date: 2026-09-01 DOI: 10.1093/pnasnexus/pgag283

Wei Qi, Ruiting Huang, Yanpeng Cai, Qian Tan, Minglei Ren, Yanli Liu

{"title":"Warming accelerates drought-flood oscillations and stratifies socioeconomic exposure.","authors":"Wei Qi, Ruiting Huang, Yanpeng Cai, Qian Tan, Minglei Ren, Yanli Liu","doi":"10.1093/pnasnexus/pgag283","DOIUrl":"10.1093/pnasnexus/pgag283","url":null,"abstract":"Anthropogenic warming intensifies the hydrological cycle, increasing the likelihood of drought and flood events. However, disaster assessments predominantly evaluate these hazards in isolation, obscuring the distinct physical characteristics and societal impacts of drought-flood alternations. Here, we integrate bias-corrected climate projections with hydrological and socioeconomic mapping to quantify the evolving dynamics of three drought-flood switching event types-drought-flood alternation events, drought-to-flood transitions, and flood-to-drought transitions-and their unequal burdens across warming levels from 1.5 to 4.5 °C in China, a region facing the world's most severe flood impacts. We show that warming systematically compresses transition intervals between drought and flood conditions, driving marked increases in the frequency and spatial extent of these event types. This physical acceleration amplifies socioeconomic exposure, revealing a stark distributional asymmetry. While wealthy regions experience the highest absolute exposure, lower-income populations face disproportionately high relative increases in human and economic exposure risks. Our results demonstrate that the temporal compression of hydrological extreme reversals creates a class of compound risk that reduces preparedness windows and stratifies vulnerability along socioeconomic lines. These findings underscore the urgency of incorporating rapid hydrological transitions into adaptation strategies to address the inequal escalation of climate risk, a critical dimension of vulnerability that has long been overlooked.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 9","pages":"pgag283"},"PeriodicalIF":4.8,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13576069/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148979199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Nicotine metabolites generate craniofacial defects that are worsened by ethanol exposure. 尼古丁代谢物产生颅面缺陷，乙醇暴露使其恶化。

IF 4.8

PNAS nexus Pub Date : 2026-09-11 eCollection Date: 2026-09-01 DOI: 10.1093/pnasnexus/pgag300

Gissela Borrego-Soto, Ian M Riddington, Esther Maier, Aneesha Baral, Luis Compean, Radhika Amin, Johann K Eberhart

{"title":"Nicotine metabolites generate craniofacial defects that are worsened by ethanol exposure.","authors":"Gissela Borrego-Soto, Ian M Riddington, Esther Maier, Aneesha Baral, Luis Compean, Radhika Amin, Johann K Eberhart","doi":"10.1093/pnasnexus/pgag300","DOIUrl":"10.1093/pnasnexus/pgag300","url":null,"abstract":"Nicotine and alcohol are two of the most consumed substances among adolescents and adults. There is great concern regarding the deleterious effects of exposure to these substances during pregnancy. Complex interactions between genes and the environment are thought to influence the severity of birth defects and can occur by altering the metabolism of substances. In humans, nicotine is mainly metabolized by CYP2A6 and variants within this enzyme associate with nicotine dependence and metabolism. Previously, we showed that embryonic nicotine exposure reduced the size of craniofacial cartilages in zebrafish. Here, we show that zebrafish metabolize nicotine similarly to humans. We demonstrate that it is not nicotine itself, but nicotine metabolites, particularly 4HPBA followed by nicotine-N'-oxide (NOX), that disrupt craniofacial development. We found that cyp2y3 mutants (the zebrafish homolog of CYP2A6) have reduced levels of nicotine metabolites and are partially protected against the craniofacial defects produced by nicotine. We also examined the effect of nicotine and ethanol co-exposure in zebrafish embryos. Surprisingly, while embryos co-exposed to nicotine and alcohol had reduced craniofacial elements, they were significantly less affected than those exposed to nicotine alone. We found that nicotine metabolites levels were decreased in embryos coexposed to nicotine and ethanol. However, alcohol worsened the craniofacial defects in embryos exposed to metabolites. Our results collectively show that nicotine is metabolized into teratogenic substances and that multifactorial interactions can alter this metabolism and subsequent teratogenicity.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 9","pages":"pgag300"},"PeriodicalIF":4.8,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13618799/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149076889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Principal bundle geometry of qualia: Understanding the quality of consciousness from symmetry. 质的主束几何：从对称理解意识的性质。

IF 4.8

PNAS nexus Pub Date : 2026-09-08 eCollection Date: 2026-09-01 DOI: 10.1093/pnasnexus/pgag261

Masafumi Oizumi, Chanseok Lim, Ryota Kanai

{"title":"Principal bundle geometry of qualia: Understanding the quality of consciousness from symmetry.","authors":"Masafumi Oizumi, Chanseok Lim, Ryota Kanai","doi":"10.1093/pnasnexus/pgag261","DOIUrl":"10.1093/pnasnexus/pgag261","url":null,"abstract":"Qualia, the subjective qualities of experience, pose a fundamental challenge to scientific explanation. A promising approach is to characterize qualia by their relational structures rather than their intrinsic nature. Assuming the structure of qualia is characterized by the geometry of neural representations, we posit that this geometry is fundamentally organized by symmetry. We propose that the principal bundle, induced by a symmetry group G acting on a neural network's state space, is the essential mathematical object uniquely characterizing this geometric structure. The core mathematical principle is that, for a G-equivariant network, its state space partitions into a quotient space Q and orbits induced by the group G. This framework reveals a three-level hierarchy for characterizing qualia. First, the choice of symmetry group G constrains the fundamental nature of the qualia modality (e.g. vision vs. audition). Second, we identify a qualia signature with a point in the quotient space Q (e.g. \"cat\"), representing the invariant identity of a percept. Third, we identify a qualia attribute with a position on a specific orbit (e.g. the cat's location), representing its continuous variations. This framework uncovers a powerful duality: the geometry of the orbits is rigid, inheriting the structure of the group G, which explains the stable relational structure of qualia attributes. In contrast, quotient-space geometry is plastic, allowing the relationships between qualia signatures to be shaped by learning. This geometric hierarchy provides a unified language for explaining the structure of perceptual experience. Furthermore, our framework generates empirical predictions and a clear research strategy for characterizing qualia and comparing qualia across individuals.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 9","pages":"pgag261"},"PeriodicalIF":4.8,"publicationDate":"2026-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13552501/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148914601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

AI and authorship: Norms and uses to preserve human-led science. 人工智能和作者身份：维护人类主导科学的规范和用途。

IF 4.8

PNAS nexus Pub Date : 2026-09-08 eCollection Date: 2026-09-01 DOI: 10.1093/pnasnexus/pgag277

Charles C Branas, Bruce L Levine

引用次数: 0

Correction to: Information from social ties predicts conspiracy beliefs: Evidence from the attempted assassination of Donald Trump. 更正：来自社会关系的信息预测阴谋论：来自暗杀唐纳德·特朗普未遂的证据。

IF 4.8

PNAS nexus Pub Date : 2026-09-08 eCollection Date: 2026-09-01 DOI: 10.1093/pnasnexus/pgag298

引用次数: 0

IF 4.8

PNAS nexus Pub Date : 2026-09-07 eCollection Date: 2026-10-01 DOI: 10.1093/pnasnexus/pgag303

John W Kurelek, Ilan M L Upfal, Supun Pieris, Kirby S Heck, Alexander Piqué, Marcus Hultmark, Michael F Howland

{"title":"Full dynamic similarity experiments and predictive modeling of wind turbine aerodynamics across control strategies.","authors":"John W Kurelek, Ilan M L Upfal, Supun Pieris, Kirby S Heck, Alexander Piqué, Marcus Hultmark, Michael F Howland","doi":"10.1093/pnasnexus/pgag303","DOIUrl":"https://doi.org/10.1093/pnasnexus/pgag303","url":null,"abstract":"Wind turbines operate in turbulent atmospheric flow that constantly changes. In field tests, the full impacts of turbine design and operation are difficult to measure because confounding effects from atmospheric flow cannot be controlled. We address the gap in controlled experiments of wind turbines across control settings at dynamic similarity using a unique experimental framework that enables representative study of full-scale wind turbines in a laboratory-sized wind tunnel by pressurizing up to 220 atmospheres. This pressurization enables high-throughput experiments of a scaled wind turbine, at high Reynolds numbers and across yaw-misalignments and tip speed ratios relevant to commercial wind turbines. The results confirm that control strategies currently in use that were designed for turbines operating in ideal conditions without yaw misalignment should be modified, as the tip speed ratio that maximizes power depends on the yaw angle. Critically, the changes in forces and power with misalignment angle strongly depend on the tip speed ratio. We present a Unified Wind Turbine (UWT) model, which accurately predicts the behavior observed in these controlled experiments. The reliability of the UWT model to predict the synergistic effects of yaw misalignment and tip speed ratio enables its use in wind turbine design and wind farm flow control optimization to maximize the energy production and value of wind power systems. The cost-efficient experimental testbed in a pressurized wind tunnel presented herein offers a unique opportunity to study aerodynamics at dynamic similarity with large-scale, commercial turbines without many confounding effects and challenges faced in performing field tests.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 10","pages":"pgag303"},"PeriodicalIF":4.8,"publicationDate":"2026-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13626229/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149119792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Detecting and characterizing restricted diffusion with accessible magnetic field gradients. 利用可达磁场梯度检测和表征受限扩散。

IF 4.8

PNAS nexus Pub Date : 2026-09-05 eCollection Date: 2026-09-01 DOI: 10.1093/pnasnexus/pgag293

Alfredo Ordinola, Magnus Herberthson, Walker Scot Jackson, Evren Özarslan

{"title":"Detecting and characterizing restricted diffusion with accessible magnetic field gradients.","authors":"Alfredo Ordinola, Magnus Herberthson, Walker Scot Jackson, Evren Özarslan","doi":"10.1093/pnasnexus/pgag293","DOIUrl":"10.1093/pnasnexus/pgag293","url":null,"abstract":"For over 50 years, diffusion magnetic resonance has been employed in numerous studies on characterizing chemical compounds, porous media, and biological tissues. These studies have almost exclusively employed the Stejskal-Tanner (ST) pulse sequence, which is sensitive to the ensemble average propagator (EAP). EAP is a compromised version of the true diffusion propagator-a quantity that fully describes the diffusion process in any system and holds exquisite information that can be used to characterize complex samples. Recently, a new diffusion sensitization method was proposed, here referred to as PROP, and was shown to be capable of acquiring the true diffusion propagator in closed pores. However, its adequate use requires a large number of measurements and (consequently) a long acquisition time. Thus, its translation to, e.g. the clinical field, is challenging. Here, we propose a reduced PROP pulse sequence (rPROP) which offers various advantages over the ST sequence. rPROP excels at isolating restricted diffusion thanks to its inherently high diffusion-weighting, yielding an efficient free diffusion filter. We employ rPROP to study different samples, and compare its performance to ST measurements in terms of estimation accuracy and gradient amplitude requirements. Furthermore, we study the capability of rPROP to detect anisotropic diffusion in samples which predominantly feature isotropic diffusion. Finally, we present a method capable of acquiring the mean position distribution (analogous to the EAP attainable via ST data) of particles via MR measurements. We highlight that all signals and images presented in this work were acquired using a benchtop MRI scanner.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 9","pages":"pgag293"},"PeriodicalIF":4.8,"publicationDate":"2026-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13586765/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149009267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Self-reported aggressiveness does not follow facial masculinization in diverse South Asian populations. 在南亚不同人群中，自我报告的攻击性并不遵循面部男性化。

IF 4.8

PNAS nexus Pub Date : 2026-09-04 eCollection Date: 2026-09-01 DOI: 10.1093/pnasnexus/pgag299

Karel Kleisner, Zuzana Štěrbová, Vojtěch Fiala, Eliška Podgorná, Abhishikta Ghosh Roy, Banita Behera, Deepika Rani, Kewal Krishan, Stanzin Namga, Sanzida Khatun, Abdul Raheem Jesmil, Abdul Hameed, Viktor Černý

{"title":"Self-reported aggressiveness does not follow facial masculinization in diverse South Asian populations.","authors":"Karel Kleisner, Zuzana Štěrbová, Vojtěch Fiala, Eliška Podgorná, Abhishikta Ghosh Roy, Banita Behera, Deepika Rani, Kewal Krishan, Stanzin Namga, Sanzida Khatun, Abdul Raheem Jesmil, Abdul Hameed, Viktor Černý","doi":"10.1093/pnasnexus/pgag299","DOIUrl":"10.1093/pnasnexus/pgag299","url":null,"abstract":"It has been suggested that sexually dimorphic facial traits are related to competitive behavior and aggression, but empirical evidence remains inconsistent and is based on a small number of populations and culturally homogeneous samples. We have combined geometric morphometric analyses with hierarchical Bayesian modeling of sixteen culturally and geographically diverse but understudied ethnic groups in order to test whether self-reported aggression covaries with facial sexual shape dimorphism within and between populations. Across populations, we found no consistent association between the individual level of facial sexual dimorphism and self-reported aggression in either sex. Although populations did differ in mean aggression levels, mean self-reported aggression covaried neither with the magnitude of sexual dimorphism nor with overall facial masculinization. Finally, sex differences in self-reported aggression did not reflect morphological sex differences. These findings challenge the generalizability of claims that aggression is encoded in the sexually dimorphic facial structure.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 9","pages":"pgag299"},"PeriodicalIF":4.8,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13596738/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149026983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Limb restraint induces a rapid and profound decrease in core body temperature associated with the stress response in mice. 肢体约束诱导与应激反应相关的小鼠核心体温迅速而深刻地下降。

IF 4.8

PNAS nexus Pub Date : 2026-09-04 eCollection Date: 2026-09-01 DOI: 10.1093/pnasnexus/pgag301

Masashi Watanave, Rei Izumi, Momoka Aizaki, Takumi Hatai, Naoi Sakaguchi, Sakura Hayashi, Miho Ashikawa, Megumi Eguchi, Hayato Umehara, Shun Yamaguchi

{"title":"Limb restraint induces a rapid and profound decrease in core body temperature associated with the stress response in mice.","authors":"Masashi Watanave, Rei Izumi, Momoka Aizaki, Takumi Hatai, Naoi Sakaguchi, Sakura Hayashi, Miho Ashikawa, Megumi Eguchi, Hayato Umehara, Shun Yamaguchi","doi":"10.1093/pnasnexus/pgag301","DOIUrl":"10.1093/pnasnexus/pgag301","url":null,"abstract":"Stress responses are triggered by diverse stressors and typically involve acute common physiological changes including increased heart rate and adrenocortical hormone secretion. In contrast, core body temperature (Tc) may either increase or decrease depending on the stressor. Although restraint is widely used to induce stress responses in laboratory animals, heterogeneous effects on Tc have been reported. To elucidate the central and peripheral mechanisms underlying restraint-induced hypothermia, a reliable model that consistently induces hypothermia is first required. In this study, we aimed to establish an experimental system using mice that can reliably induce hypothermia through physical restraint. Furthermore, we aimed to elucidate the primary factors contributing to hypothermia within the various elements constituting the restrained state and to simplify the restraint experimental system by eliminating unnecessary elements. Starting with conventional cylinder-shaped restraint equipment and modifying it in various ways, we finally found that the simple procedure of limb restraint reliably induces a rapid (within 15 min) and substantial (∼4 °C) decrease in rectal temperature, a good indicator of Tc. Limb restraint increased serum corticosterone concentration and activated the paraventricular hypothalamic nucleus, suggesting that a type of stress response involving Tc reduction was induced by limb restraint. The decrease in body temperature caused by limb restraint was attributed, at least in part, to reduced heat production in the brown adipose tissue and increased heat loss from the tail. This simplified restraint paradigm provides a useful tool for elucidating the mechanisms underlying hypothermia induced by physical restraint.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 9","pages":"pgag301"},"PeriodicalIF":4.8,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13596739/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149026999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Slovotvir: Grassroots reform of the Ukrainian language reveals the role of drift and selection in language change. Slovotvir：乌克兰语的基层改革揭示了漂移和选择在语言变化中的作用。

IF 4.8

PNAS nexus Pub Date : 2026-09-03 eCollection Date: 2026-09-01 DOI: 10.1093/pnasnexus/pgag258

Alexey Koshevoy, Oleg Sobchuk, Olivier Morin

{"title":"Slovotvir: Grassroots reform of the Ukrainian language reveals the role of drift and selection in language change.","authors":"Alexey Koshevoy, Oleg Sobchuk, Olivier Morin","doi":"10.1093/pnasnexus/pgag258","DOIUrl":"10.1093/pnasnexus/pgag258","url":null,"abstract":"Language change involves a complex interplay of selection and drift (or unbiased copying), shaping the popularity of words over time. This pre-registered study examines lexical evolution in the Ukrainian language using data from Slovotvir, a crowdsourcing platform where over 4,000 users proposed and ranked translations of foreign-origin words over 9 years. We rely on an agent-based model combined with novel generative inference methods to investigate the roles of frequency-dependent selection, selection for brevity, and random drift in shaping word popularity. Our results indicate that Slovotvir users exhibit a preference for shorter words, supporting Zipf's principle of least effort. However, the popularity of translations, which we approximate using likes on the platform, appears largely frequency-independent, suggesting that users do not disproportionately favor already popular words. However, this conclusion might be limited by the fact that our data consist of low-frequency neologisms that are still evolving in this population of speakers. These findings contribute to a broader understanding of language change by providing empirical evidence that selection for brevity, rather than frequency-dependent selection, drives lexical evolution in this grassroots language reform initiative, which reflects and shaped real-world language change.","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"5 9","pages":"pgag258"},"PeriodicalIF":4.8,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13540719/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148889034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0