PNAS nexusPub Date : 2025-09-01DOI: 10.1093/pnasnexus/pgaf280
Katherine L Milkman, Sean F Ellis, Dena M Gromet, Isabella M DeMay, Heather N Graci, Youngwoo Jung, Rayyan S Mobarak, Ramon A Silvera Zumaran, Mia N Simmons, Christophe Van den Bulte, Shlomo Benartzi, Matthew Hilchey, Laura Goodyear, Dean Karlan, Nina Mazar, Daniel Mochon, Avni M Shah, Dilip Soman, Jonathan Zinman, Angela L Duckworth
{"title":"Can reminder emails compel Americans to save? A two-million-person megastudy.","authors":"Katherine L Milkman, Sean F Ellis, Dena M Gromet, Isabella M DeMay, Heather N Graci, Youngwoo Jung, Rayyan S Mobarak, Ramon A Silvera Zumaran, Mia N Simmons, Christophe Van den Bulte, Shlomo Benartzi, Matthew Hilchey, Laura Goodyear, Dean Karlan, Nina Mazar, Daniel Mochon, Avni M Shah, Dilip Soman, Jonathan Zinman, Angela L Duckworth","doi":"10.1093/pnasnexus/pgaf280","DOIUrl":"10.1093/pnasnexus/pgaf280","url":null,"abstract":"<p><p>In the United States, 24% of adults have no savings and 39% have less than a month of income saved. We present results from a megastudy where nearly 2 million customers of a US bank were randomly assigned to receive one of seven different 2-month email campaigns, each employing a different behavioral science insight to nudge one-time and recurring savings deposits and increase savings balances or to a control condition without such messages. These campaigns increased the probability of making a one-time savings deposit, on average, by 0.05 percentage points (a 0.51% increase over control). The best-performing campaign delivered weekly messages to customers that differed depending on recent savings behavior: messages to customers who had not made a savings account deposit in the last week included a simple reminder to save, while those to customers who had made a savings account deposit in the prior week were congratulated on this accomplishment. This top-performing campaign increased the monthly likelihood that a customer made a one-time savings deposit by 0.13 percentage points (a 1.32% increase). We estimate that rolling this 2-month campaign out to everyone in our megastudy population would have led to an extra $6,123,996 to $9,910,090 in savings. Together, our findings highlight that light-touch, frequent email nudges can cost-effectively create small increases in savings deposits in the United States. Ideally, to generate meaningful benefits, behavioral science insights would be incorporated into a wider range of communications and incentives designed by financial institutions.</p>","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 9","pages":"pgaf280"},"PeriodicalIF":3.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12477529/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145202382","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}
PNAS nexusPub Date : 2025-09-01DOI: 10.1093/pnasnexus/pgaf278
Tomoyasu Noji, Keisuke Saito, Hiroshi Ishikita
{"title":"Energetics of tryptophan residues in electron transfer and photoprotection of type-II photosynthetic reaction centers.","authors":"Tomoyasu Noji, Keisuke Saito, Hiroshi Ishikita","doi":"10.1093/pnasnexus/pgaf278","DOIUrl":"10.1093/pnasnexus/pgaf278","url":null,"abstract":"<p><p>Tryptophan is the strongest UV chromophore in proteins, and its biosynthesis is the most energy-consuming among all amino acids. In the transmembrane region of purple bacterial photosynthetic reaction centers (PbRC), tryptophan residues are densely concentrated near the inactive electron-transfer branch in subunit M, forming part of the carotenoid binding site. We investigated the redox potentials (<i>E</i> <sub>m</sub>) of tryptophan residues in PbRC and O<sub>2</sub>-evolving photosystem II (PSII) by solving the linear Poisson-Boltzmann equation, considering equilibrium with all titratable sites in the entire protein. The tryptophan mediating superexchange electron transfer between the active (bacterio)pheophytin and primary quinone exhibits the highest <i>E</i> <sub>m</sub> value in both PbRC and PSII. In contrast, in PSII, D1-Trp14, oxidized under strong light to trigger the degradation of photodamaged D1 protein, has the lowest <i>E</i> <sub>m</sub> value. In PbRC, a chain of tryptophan residues near the inactive branch forms an <i>E</i> <sub>m</sub> cascade. Quantum mechanical/molecular mechanical calculations suggest that this chain enables electron hole hopping toward the carotenoid, effectively dissipating harmful UV energy. This mechanism likely reflects the photoprotective strategy of PbRC, focusing on UV tolerance rather than oxidative stress.</p>","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 9","pages":"pgaf278"},"PeriodicalIF":3.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12445680/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145115425","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}
PNAS nexusPub Date : 2025-08-29eCollection Date: 2025-09-01DOI: 10.1093/pnasnexus/pgaf275
Arthur Prat-Carrabin, Samuel J Gershman
{"title":"Bayesian estimation yields anti-Weber variability.","authors":"Arthur Prat-Carrabin, Samuel J Gershman","doi":"10.1093/pnasnexus/pgaf275","DOIUrl":"10.1093/pnasnexus/pgaf275","url":null,"abstract":"<p><p>A classic result of psychophysics is that human perceptual estimates are more variable for larger magnitudes. This \"Weber behavior,\" however, has typically not been the focus of the prominent Bayesian paradigm. Here, we examine the variability of a Bayesian observer in comparison with human subjects. In two preregistered experiments, we manipulate the prior distribution and the reward function in a numerosity-estimation task. When large numerosities are more frequent or more rewarding, the Bayesian observer exhibits an \"anti-Weber behavior,\" in which larger magnitudes yield less variable responses. Human subjects exhibit a similar pattern, thus breaking a long-standing result of psychophysics. Nevertheless, subjects' responses are best reproduced by a logarithmic encoding of magnitudes, a proposal of Fechner often regarded as accounting for Weber behavior. We thus obtain an anti-Weber behavior together with a Fechner encoding. Our results suggest that the increasing variability may be primarily due to the skewness of natural priors.</p>","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 9","pages":"pgaf275"},"PeriodicalIF":3.8,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12448889/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145115424","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}
{"title":"What values best distinguish the world's cultures? The machine learning-based cultural values inventory.","authors":"Abhishek Sheetal, Shilpa Madan, Rui Ling Lee, Krishna Savani","doi":"10.1093/pnasnexus/pgaf229","DOIUrl":"10.1093/pnasnexus/pgaf229","url":null,"abstract":"<p><p>Scientists studying culture typically focus on a small number of theoretical constructs, such as individualism-collectivism, when seeking to explain cultural differences in psychological tendencies and behaviors. However, existing theories of culture could have missed out on important constructs that are useful for explaining cross-cultural differences. We used an abductive approach combining prediction and explanation to uncover important cultural values. In the prediction phase, based on 594 attitudes, values, and beliefs included in the World Values Survey, a neural network could classify respondents' nationalities with 90% accuracy in out-of-sample data. In the explanation phase, a feature importance analysis identified the values that contributed the most to predicting individuals' countries of origin. The top 60 variables resulting from this analysis were used to create the <i>machine learning-based cultural values inventory</i> (ML-CVI), a tool to help future researchers uncover explanations for cross-cultural differences. Four follow-up studies demonstrated ML-CVI's theoretical and practical relevance. Specifically, Americans were less likely than Mexicans to comply with COVID-19 lockdowns, and this difference was explained by Americans' stronger Christian nationalism. Moreover, Indians were more likely than Americans to engage in proenvironmental behavior, and this difference was driven by Indians' stronger perseverance. Thus, the ML-CVI broadens the range of explanatory factors available to researchers by helping them identify explanations for cultural differences that they would not have been able to identify based on traditional theories of cultural values. Overall, this research highlights that machine learning-based abductive reasoning can help expand the range of explanatory frameworks in social science research.</p>","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 8","pages":"pgaf229"},"PeriodicalIF":3.8,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12378846/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144981777","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}
PNAS nexusPub Date : 2025-08-26eCollection Date: 2025-08-01DOI: 10.1093/pnasnexus/pgaf265
{"title":"Correction to: Establishment of blood glycosidase activities and their excursions in sepsis.","authors":"","doi":"10.1093/pnasnexus/pgaf265","DOIUrl":"10.1093/pnasnexus/pgaf265","url":null,"abstract":"<p><p>[This corrects the article DOI: 10.1093/pnasnexus/pgac113.].</p>","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 8","pages":"pgaf265"},"PeriodicalIF":3.8,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12379886/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144981764","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}
PNAS nexusPub Date : 2025-08-26eCollection Date: 2025-08-01DOI: 10.1093/pnasnexus/pgaf237
Russell Roberts, Reid Hastie, Alexander Todorov
{"title":"People calibrate future expectations to past performance when predicting transparently random events.","authors":"Russell Roberts, Reid Hastie, Alexander Todorov","doi":"10.1093/pnasnexus/pgaf237","DOIUrl":"10.1093/pnasnexus/pgaf237","url":null,"abstract":"<p><p>We report on five experiments studying people's (<i>n</i> > 12,000) responses to a prototypical random process: predicting the outcomes in a sequence of five fair coin tosses. \"Success\" rates in making predictions followed the binomial distribution, and randomly assigned participants to zero to five success experiences, capturing the entire distribution of possible performance outcomes without deception. We found that more successful predictions led to more optimistic expectations of future performance and an increased propensity for risk-taking behaviors, whereas more unsuccessful predictions led to more pessimistic expectations and risk-averse behavior, demonstrating the tendency to believe that there is a signal in performance predicting random sequences of events. Inference from performance was stronger for participants who changed their predictions more often, suggesting that it is more likely to emerge when participants detect a spurious correlation between their behavior and the experienced outcomes. The findings could not be explained by distorted beliefs about the nature of the outcome-generating process, poor knowledge of probability, or risk attitudes, and were unaffected by the presence of performance-related rewards.</p>","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 8","pages":"pgaf237"},"PeriodicalIF":3.8,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12378910/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144981788","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}
PNAS nexusPub Date : 2025-08-26eCollection Date: 2025-08-01DOI: 10.1093/pnasnexus/pgaf239
Michael E W Varnum, Amanda P Kirsch, Daniel J Beal, Cari M Pick, Laith Al-Shawaf, Chiara Ambrosio, Maria Teresa Barbato, Oumar Barry, Watcharaporn Boonyasiriwat, Eduard Brandstätter, Suzan Ceylan-Batur, Marco Antonio Correa Varella, Julio Eduardo Cruz, Oana David, Laina Ngom Dieng, Dimitri Dubois, Ana María Fernandez, Silvia Galdi, Oscar Javier Galindo Caballero, Sylvie Graf, Igor Grossmann, David Guzman, Peter Halama, Takeshi Hamamura, Martina Hřebíčková, Ioana Iuga, Lady Javela, Jaewuk Jung, Johannes A Karl, Jinseok P Kim, Michal Kohút, Anthonieta Looman Mafra, Dieynaba Gabrielle Ndiaye, Jiaqing O, Beatriz Perez Sánchez, Eric Roth Unzueta, Muhammad Rizwan, A Timur Sevincer, Eric Skoog, Eunkook M Suh, Daniel Sznycer, Evelina Thunell, Arnaud Tognetti, Ayse K Uskul, Jaroslava Varella Valentova, Yunsuh Nike Wee, Anja Lundkvist Winter, Torin Peter Young, Danilo Zambrano, Anna Ziska, Douglas T Kenrick
{"title":"Commonly observed sex differences in direct aggression are absent or reversed in sibling contexts.","authors":"Michael E W Varnum, Amanda P Kirsch, Daniel J Beal, Cari M Pick, Laith Al-Shawaf, Chiara Ambrosio, Maria Teresa Barbato, Oumar Barry, Watcharaporn Boonyasiriwat, Eduard Brandstätter, Suzan Ceylan-Batur, Marco Antonio Correa Varella, Julio Eduardo Cruz, Oana David, Laina Ngom Dieng, Dimitri Dubois, Ana María Fernandez, Silvia Galdi, Oscar Javier Galindo Caballero, Sylvie Graf, Igor Grossmann, David Guzman, Peter Halama, Takeshi Hamamura, Martina Hřebíčková, Ioana Iuga, Lady Javela, Jaewuk Jung, Johannes A Karl, Jinseok P Kim, Michal Kohút, Anthonieta Looman Mafra, Dieynaba Gabrielle Ndiaye, Jiaqing O, Beatriz Perez Sánchez, Eric Roth Unzueta, Muhammad Rizwan, A Timur Sevincer, Eric Skoog, Eunkook M Suh, Daniel Sznycer, Evelina Thunell, Arnaud Tognetti, Ayse K Uskul, Jaroslava Varella Valentova, Yunsuh Nike Wee, Anja Lundkvist Winter, Torin Peter Young, Danilo Zambrano, Anna Ziska, Douglas T Kenrick","doi":"10.1093/pnasnexus/pgaf239","DOIUrl":"10.1093/pnasnexus/pgaf239","url":null,"abstract":"<p><p>Decades of research support the generalization that human males tend to be more aggressive than females. However, most of that research has examined aggression between unrelated individuals. Data drawn from 24 societies around the globe (<i>n</i> = 4,013) indicate that this generalization does not hold in the context of sibling relationships. In retrospective self-reports, females report being at least as aggressive as males toward their siblings, often more so. This holds for direct as well as indirect aggression, and for aggression between adult siblings as well as aggression that occurred during childhood. Consistent with prior research on sex differences, males reported engaging in more direct aggression toward nonkin than did females in the majority of societies. The results suggest that the dynamics of aggression within the family are different from those outside of it, and ultimately that understanding the role of sex in aggressive tendencies depends on context and target.</p>","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 8","pages":"pgaf239"},"PeriodicalIF":3.8,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12378733/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144981814","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}
PNAS nexusPub Date : 2025-08-26eCollection Date: 2025-08-01DOI: 10.1093/pnasnexus/pgaf220
Zuzana Kocsisova, Elena D Bagatelas, Jesus Santiago-Borges, Hanyue Cecilia Lei, Brian M Egan, Matthew C Mosley, Aaron M Anderson, Daniel L Schneider, Tim Schedl, Kerry Kornfeld
{"title":"Notch signaling in germ line stem cells controls reproductive aging in <i>Caenorhabditis elegans</i>.","authors":"Zuzana Kocsisova, Elena D Bagatelas, Jesus Santiago-Borges, Hanyue Cecilia Lei, Brian M Egan, Matthew C Mosley, Aaron M Anderson, Daniel L Schneider, Tim Schedl, Kerry Kornfeld","doi":"10.1093/pnasnexus/pgaf220","DOIUrl":"10.1093/pnasnexus/pgaf220","url":null,"abstract":"<p><p>Adult stem cells maintain and rejuvenate a wide range of tissues, and the progressive, age-related decline of adult stem cells is a hallmark of aging. We propose that the <i>Caenorhabditis elegans</i> germline is an experimentally tractable model of adult stem cell aging and that stem cell exhaustion is a cause of reproductive senescence. Because these are the only stem cells in adult worms, this system provides a unique opportunity to exploit the power of <i>C. elegans</i> to address stem cell exhaustion during aging. Here, we show that reproductive aging occurs early in adult life in multiple species in the genus <i>Caenorhabditis</i>, indicating that this is a feature of both female/male and hermaphrodite/male species. Our results indicate that cellular and molecular changes in germline stem cells are a cause of reproductive aging, since we demonstrated that defects in stem cell number and activity were well correlated with extended progeny production in <i>daf-2</i>, <i>eat-2</i>, and <i>phm-2 C. elegans</i> mutants. Ectopic expression of the Notch effector SYGL-1 in germ line stem cells was sufficient to delay stem cell aging, indicating that the conserved Notch pathway can act cell autonomously to control age-related decline of adult stem cells. These animals displayed increased progeny production in midlife without a depression of early progeny production, a pattern of reproductive aging distinct from previous mutants. These results suggest that age-related declines of stem cell number and activity are a cause of reproductive aging in <i>C. elegans</i> and the Notch signaling pathway may be a control point that mediates this decline.</p>","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 8","pages":"pgaf220"},"PeriodicalIF":3.8,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12380048/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144981780","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}
{"title":"Versatile phenolic composites by in situ polymerization of concentrated dispersions of carbon nanotubes.","authors":"Zhilong Yu, Chier Zhang, Mingtao Chen, Jiaxing Huang","doi":"10.1093/pnasnexus/pgaf274","DOIUrl":"10.1093/pnasnexus/pgaf274","url":null,"abstract":"<p><p>Uniform dispersion of carbon nanotubes in a polymer matrix is a prerequisite for high-performance nanotube-based composites. Here, we report an in situ polymerization route to synthesize a range of phenolic composites with high loading of single-wall carbon nanotubes (SWCNTs, >40 wt%) and continuously tunable viscoelasticity. SWCNTs can be directly and uniformly dispersed in cresols through noncovalent charge-transfer interactions without the need for surfactants, and further concentrated before in situ polymerization of the solvent molecules, yielding phenolic composites in the forms of conductive pastes, highly stretchy doughs, and hardened solids with high nanotube loading and much enhanced electrical conductivity (up to 2.7 × 10<sup>4</sup> S m<sup>-1</sup>). These conducting phenolic composites provide a versatile material foundation for many areas. As a proof of concept, the conductive paste is used to construct ultrasensitive motion sensors that can operate at unprecedently low voltages (e.g. 0.1-10 mV). Moreover, the ease of processing and shaping of phenolic composite solids from the dough state is demonstrated.</p>","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 9","pages":"pgaf274"},"PeriodicalIF":3.8,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12415859/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145031394","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}
PNAS nexusPub Date : 2025-08-21eCollection Date: 2025-09-01DOI: 10.1093/pnasnexus/pgaf273
Forwood Wiser, Siddhartha Sen, Zhizhao Wang, Julia Lee-Taylor, Kelley C Barsanti, John Orlando, Daniel M Westervelt, Daven K Henze, Arlene M Fiore, Alexander Berman, Reese Carter, V Faye McNeill
{"title":"A graph theory-based algorithm for the reduction of atmospheric chemical mechanisms.","authors":"Forwood Wiser, Siddhartha Sen, Zhizhao Wang, Julia Lee-Taylor, Kelley C Barsanti, John Orlando, Daniel M Westervelt, Daven K Henze, Arlene M Fiore, Alexander Berman, Reese Carter, V Faye McNeill","doi":"10.1093/pnasnexus/pgaf273","DOIUrl":"10.1093/pnasnexus/pgaf273","url":null,"abstract":"<p><p>The atmospheric chemistry of volatile organic compounds (VOC) has a major influence on atmospheric pollutants and particle formation. Accurate modeling of this chemistry is essential for air quality models. Complete representations of VOC oxidation chemistry are far too large for spatiotemporal simulations of the atmosphere, necessitating reduced mechanisms. We present Automated MOdel REduction version 2.0, an algorithm for the reduction of any VOC oxidation mechanism to a desired size by removing, merging, and rerouting sections of the graph representation of the mechanism. We demonstrate the algorithm on isoprene (398 species) and camphene (103,694 species) chemistry. We remove up to 95% of isoprene species while improving upon prior reduced isoprene mechanisms by 53-67% using a multispecies metric. We remove 99% camphene species while accurately matching camphene secondary organic aerosol production simulated using the full mechanism. This algorithm will bridge the gap between large and reduced mechanisms, helping to improve air quality models.</p>","PeriodicalId":74468,"journal":{"name":"PNAS nexus","volume":"4 9","pages":"pgaf273"},"PeriodicalIF":3.8,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12403060/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144994646","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}
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