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1. Technical note: The enhancement limit of coagulation scavenging of small charged particles

   https://doi.org/10.5194/acp-21-3827-2021  

   Mahfouz, Naser G.; Donahue, Neil M. (January 2021, Atmospheric Chemistry and Physics)

   null (Ed.)

   Abstract. We show that the limit of the enhancement of coagulation scavenging of charged particles is 2, that is, doubled compared to the neutral case.Because the particle survival probability decreases exponentially as the coagulation sink increases, everything else being equal, the doubling of the coagulation sink can amount to a dramatic drop in survival probability – squaring the survival probability, p2, where p≤1 is the survival probability in the neutral case.Thus, it is imperative to consider this counterbalancing effect when studying ion-induced new-particle formation and ion-enhanced new-particle growth in the atmosphere. 

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2. A Survival Analysis of the Gulf Stream Warm Core Rings

   https://doi.org/10.1029/2020JC016507  

   Silva, E. Nishchitha S.; Gangopadhyay, Avijit; Fay, Gavin; Welandawe, Manushi K. V.; Gawarkiewicz, Glen; Silver, Adrienne M.; Monim, Mahmud; Clark, Jenifer (October 2020, Journal of Geophysical Research: Oceans)

   Abstract Survival of Gulf Stream (GS) warm core rings (WCRs) was investigated using a census consisting of a total of 961 rings formed during the period 1980–2017. Kaplan‐Meier survival probability and Cox hazard proportional models were used for the analysis. The survival analysis was performed for rings formed in four 5° zones between 75° W and 55° W. The radius, latitude, and distance from the shelf‐break of a WCR at formation all had a significant effect on the survival of WCRs. A pattern of higher survival was observed in WCRs formed in Zone 2 (70°–65° W) or Zone 3 (65°–60° W) and then demised in Zone 1 (75°–70° W). Survival probability of the WCRs increased to more than70%for those formed within a latitude band from 39.5° to 41.5° N. Survival probability is reduced when the WCRs are formed near the New England Seamounts. 

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3. Sex‐specific recruitment rates contribute to male‐biased sex ratio in Adélie penguins

   https://doi.org/10.1002/ece3.10859  

   Morandini, Virginia; Dugger, Katie M; Schmidt, Annie E; Varsani, Arvind; Lescroël, Amélie; Ballard, Grant; Lyver, Phil O'B; Barton, Kerry; Ainley, David G (February 2024, Ecology and Evolution)

   Abstract Sex‐related differences in vital rates that drive population change reflect the basic life history of a species. However, for visually monomorphic bird species, determining the effect of sex on demographics can be a challenge. In this study, we investigated the effect of sex on apparent survival, recruitment, and breeding propensity in the Adélie penguin (Pygoscelis adeliae), a monochromatic, slightly size dimorphic species with known age, known sex, and known breeding history data collected during 1996–2019 (n = 2127 birds) from three breeding colonies on Ross Island, Antarctica. Using a multistate capture–mark–recapture maximum‐likelihood model, we estimated apparent survival (), recapture (resighting) probability (), and the probability of transitioning among breeding states and moving between colonies (; colony‐specific non‐juvenile pre‐breeders, breeders, and non‐breeders). Survival rate varied by breeding status and colony, but not sex, and pre‐breeders had higher survival rates than breeders and non‐breeders. Females had a higher probability of recruiting into the breeding population each year and may enter the breeding pool at younger ages. In contrast, both sexes had the same probability of breeding from year to year once they had recruited. Although we detected no direct sex effects on survival, the variation in recruitment probability and age‐at‐first reproduction, along with lower survival rates of breeders compared to pre‐breeders, likely leads to shorter lifespans for females. This is supported by our findings of a male‐biased mean adult sex ratio (ASR) of 1.4 males for every female ( proportion of males = 0.57, SD = 0.07) across all colonies and years in this metapopulation. Our study illustrates how important it can be to disentangle sex‐related variation in population vital rates, particularly for species with complex life histories and demographic dynamics. 

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4. DeFi Survival Analysis: Insights into Risks and User Behaviors

   https://doi.org/10.1007/978-3-031-18679-0_8  

   Green, Aaron; Cammilleri, Christopher; Erickson, John S; Seneviratne, Oshani; Bennett, Kristin P (February 2023, The International Conference on Mathematical Research for Blockchain Economy)

   Pardalos, Panos; Kotsireas, Ilias; Guo, Yike; Knottenbelt, William (Ed.)

   We propose a decentralized finance (DeFi) survival analysis approach for discovering and characterizing user behavior and risks in lending protocols. We demonstrate how to gather and prepare DeFi transaction data for survival analysis. We demonstrate our approach using transactions in AAVE, one of the largest lending protocols. We develop a DeFi survival analysis pipeline which first prepares transaction data for survival analysis through the selection of different index events (or transactions) and associated outcome events. Then we apply survival analysis statistical and visualization methods such as median survival times, Kaplan–Meier survival curves, and Cox hazard regression to gain insights into usage patterns and risks within the protocol. We show how by varying the index and outcome events, we can utilize DeFi survival analysis to answer three different questions. What do users do after a deposit? How long until borrows are first repaid or liquidated? How does coin type influence liquidation risk? The proposed DeFi survival analysis can easily be generalized to other DeFi lending protocols. By defining appropriate index and outcome events, DeFi survival analysis can be applied to any cryptocurrency protocol with transactions. 

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5. Survival of newly formed particles in haze conditions

   https://doi.org/10.1039/D2EA00007E  

   Marten, Ruby; Xiao, Mao; Rörup, Birte; Wang, Mingyi; Kong, Weimeng; He, Xu-Cheng; Stolzenburg, Dominik; Pfeifer, Joschka; Marie, Guillaume; Wang, Dongyu S.; et al (May 2022, Environmental Science: Atmospheres)

   Intense new particle formation events are regularly observed under highly polluted conditions, despite the high loss rates of nucleated clusters. Higher than expected cluster survival probability implies either ineffective scavenging by pre-existing particles or missing growth mechanisms. Here we present experiments performed in the CLOUD chamber at CERN showing particle formation from a mixture of anthropogenic vapours, under condensation sinks typical of haze conditions, up to 0.1 s −1 . We find that new particle formation rates substantially decrease at higher concentrations of pre-existing particles, demonstrating experimentally for the first time that molecular clusters are efficiently scavenged by larger sized particles. Additionally, we demonstrate that in the presence of supersaturated gas-phase nitric acid (HNO 3 ) and ammonia (NH 3 ), freshly nucleated particles can grow extremely rapidly, maintaining a high particle number concentration, even in the presence of a high condensation sink. Such high growth rates may explain the high survival probability of freshly formed particles under haze conditions. We identify under what typical urban conditions HNO 3 and NH 3 can be expected to contribute to particle survival during haze. 

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