Damage to tropical forests caused by cyclones is driven by wind speed but mediated by topographical exposure and tree characteristics.

Each year, an average of 45 tropical cyclones affect coastal areas and potentially impact forests. The proportion of the most intense cyclones has increased over the past four decades and is predicted to continue to do so. Yet, it remains uncertain how topographical exposure and tree characteristics can mediate the damage caused by increasing wind speed. Here, we compiled empirical data on the damage caused by 11 cyclones occurring over the past 40 years, from 74 forest plots representing tropical regions worldwide, encompassing field data for 22,176 trees and 815 species. We reconstructed the wind structure of those tropical cyclones to estimate the maximum sustained wind speed (MSW) and wind direction at the studied plots. Then, we used a causal inference framework combined with Bayesian generalised linear mixed models to understand and quantify the causal effects of MSW, topographical exposure to wind (EXP), tree size (DBH) and species wood density (ρ) on the proportion of damaged trees at the community level, and on the probability of snapping or uprooting at the tree level. The probability of snapping or uprooting at the tree level and, hence, the proportion of damaged trees at the community level, increased with increasing MSW, and with increasing EXP accentuating the damaging effects of cyclones, in particular at higher wind speeds. Higher ρ decreased the probability of snapping and to a lesser extent of uprooting. Larger trees tended to have lower probabilities of snapping but increased probabilities of uprooting. Importantly, the effect of ρ decreasing the probabilities of snapping was more marked for smaller than larger trees and was further accentuated at higher MSW. Our work emphasises how local topography, tree size and species wood density together mediate cyclone damage to tropical forests, facilitating better predictions of the impacts of such disturbances in an increasingly windier world.

Negative Social Exchanges During the Pandemic, Loneliness, and the Mediating Role of Stress and Feeling Misunderstood Among People at High-Risk for COVID-19 Related Complications.

The goal of this study was to investigate the links between social interactions and mental health for people who are high-risk for COVID-19 complications. Specifically, we tested the relationships between negative social exchanges during the pandemic and loneliness through two mediators: stress and feeling misunderstood about one's health status. Data were collected via Amazon's MTurk from participants (N = 271) who self-identified as being high-risk for COVID-19. The results from our model showed both a direct association between negative social interactions and loneliness, and an indirect link between these variables through stress. Overall, these results highlight the importance of understanding social interactions for people who are at high-risk for COVID-19 and their mental well-being. The results and implications are discussed.

Blood and urine multi-omics analysis of the impact of e-vaping, smoking, and cessation: from exposome to molecular responses.

Cigarette smoking is a major preventable cause of morbidity and mortality. While quitting smoking is the best option, switching from cigarettes to non-combustible alternatives (NCAs) such as e-vapor products is a viable harm reduction approach for smokers who would otherwise continue to smoke. A key challenge for the clinical assessment of NCAs is that self-reported product use can be unreliable, compromising the proper evaluation of their risk reduction potential. In this cross-sectional study of 205 healthy volunteers, we combined comprehensive exposure characterization with in-depth multi-omics profiling to compare effects across four study groups: cigarette smokers (CS), e-vapor users (EV), former smokers (FS), and never smokers (NS). Multi-omics analyses included metabolomics, transcriptomics, DNA methylomics, proteomics, and lipidomics. Comparison of the molecular effects between CS and NS recapitulated several previous observations, such as increased inflammatory markers in CS. Generally, FS and EV demonstrated intermediate molecular effects between the NS and CS groups. Stratification of the FS and EV by combustion exposure markers suggested that this position on the spectrum between CS and NS was partially driven by non-compliance/dual use. Overall, this study highlights the importance of in-depth exposure characterization before biological effect characterization for any NCA assessment study.

Make No Apologies: Fear of Negative Evaluation, Depressive Symptoms, and the Mediating Role of Accounting for COVID-Safe Behavior Amongst People at High-Risk for Severe Illness.

With the goal of understanding unique and important threats to the mental health of people who are especially vulnerable to severe illness as a result of COVID-19, this study investigated associations between such individuals' fear of negative evaluation, tendency to "account for" practicing COVID-safe behaviors, and depressive symptoms. Grounded in perspectives on self-presentation, normative influence, and cognitive dissonance, we hypothesized that fear of negative evaluation would relate positively to accounting for COVID-safe behaviors, which, in turn, would associate positively with increased depressive symptoms. The results showed that increased fear of negative evaluation predicted an increased use of apologies and excuses, which in turn were positively related to depressive symptoms. Justifications for COVID-safe behaviors were not significantly associated with either fear of evaluation or depressive symptoms. The practical and theoretical implications are discussed.

Climatic conditions affect shoot flammability by influencing flammability-related functional traits in nonfire-prone habitats.

Plant flammability is an important driver of wildfires, and flammability itself is determined by several plant functional traits. While many plant traits are influenced by climatic conditions, the interaction between climatic conditions and plant flammability has rarely been investigated. Here, we explored the relationships among climatic conditions, shoot-level flammability components, and flammability-related functional traits for 186 plant species from fire-prone and nonfire-prone habitats. For species originating from nonfire-prone habitats, those from warmer areas tended to have lower shoot moisture content and larger leaves, and had higher shoot flammability with higher ignitibility, combustibility, and sustainability. Plants in wetter areas tended to have lower shoot flammability with lower combustibility and sustainability due to higher shoot moisture contents. In fire-prone habitats, shoot flammability was not significantly related to any climatic factor. Our study suggests that for species originating in nonfire-prone habitats, climatic conditions have influenced plant flammability by shifting flammability-related functional traits, including leaf size and shoot moisture content. Climate does not predict shoot flammability in species from fire-prone habitats; here, fire regimes may have an important role in shaping plant flammability. Understanding these nuances in the determinants of plant flammability is important in an increasingly fire-prone world.

Termite sensitivity to temperature affects global wood decay rates.

Deadwood is a large global carbon store with its store size partially determined by biotic decay. Microbial wood decay rates are known to respond to changing temperature and precipitation. Termites are also important decomposers in the tropics but are less well studied. An understanding of their climate sensitivities is needed to estimate climate change effects on wood carbon pools. Using data from 133 sites spanning six continents, we found that termite wood discovery and consumption were highly sensitive to temperature (with decay increasing >6.8 times per 10°C increase in temperature)-even more so than microbes. Termite decay effects were greatest in tropical seasonal forests, tropical savannas, and subtropical deserts. With tropicalization (i.e., warming shifts to tropical climates), termite wood decay will likely increase as termites access more of Earth's surface.

Limits to post-fire vegetation recovery under climate change.

Record-breaking fire seasons in many regions across the globe raise important questions about plant community responses to shifting fire regimes (i.e., changing fire frequency, severity and seasonality). Here, we examine the impacts of climate-driven shifts in fire regimes on vegetation communities, and likely responses to fire coinciding with severe drought, heatwaves and/or insect outbreaks. We present scenario-based conceptual models on how overlapping disturbance events and shifting fire regimes interact differently to limit post-fire resprouting and recruitment capacity. We demonstrate that, although many communities will remain resilient to changing fire regimes in the short-term, longer-term changes to vegetation structure, demography and species composition are likely, with a range of subsequent effects on ecosystem function. Resprouting species are likely to be most resilient to changing fire regimes. However, even these species are susceptible if exposed to repeated short-interval fire in combination with other stressors. Post-fire recruitment is highly vulnerable to increased fire frequency, particularly as climatic limitations on propagule availability intensify. Prediction of community responses to fire under climate change will be greatly improved by addressing knowledge gaps on how overlapping disturbances and climate change-induced shifts in fire regime affect post-fire resprouting, recruitment, growth rates, and species-level adaptation capacity.

Making Others Laugh is the Best Medicine: Humor Orientation, Health Outcomes, and the Moderating Role of Cognitive Flexibility.

Humor orientation is related to numerous prosocial outcomes. This study examined the relationships between humor orientation and mental well-being, loneliness, headaches, and sleep disturbances. We also tested cognitive flexibility as a moderator of these associations among (N = 406) young adults. The results showed that humor orientation was associated with increased mental well-being, lower levels of loneliness, and less headaches. The direct effect from humor orientation to sleep disturbances was not significant. The interaction effects between humor orientation and cognitive flexibility on all four health outcome variables were significant. The implications of the results are discussed in detail.

Associations Between Mother-Child Communication Apprehension, and Young Adult Resilience, Depressive Symptoms, and Self-Esteem.

This study tested associations between mother-child communication apprehension, adult child communication apprehension, and adult child resilience, self-esteem, and depressive symptoms. Data were collected from 154 mother-child dyads (N = 308) who completed measures of communication apprehension, depressive symptoms, resilience, and self-esteem. Results showed that mother communication apprehension positively predicted adult child communication apprehension. Moreover, adult child communication apprehension predicted lower levels of resilience and self-esteem, and higher levels of depressive symptoms. Mother communication apprehension indirectly predicted all three psychological outcomes for adult children through adult children's communication apprehension. We discuss the potential implications for communication apprehension and social skill training that could help families improve psychological problems.

Shoot-level flammability across the Dracophyllum (Ericaceae) phylogeny: evidence for flammability being an emergent property in a land with little fire.

Plant flammability varies across species, but the evolutionary basis for this variation is not well understood. Phylogenetic analysis of interspecific variation in flammability can provide insights into the evolution of plant flammability. We measured four components of flammability (ignitability, sustainability, combustibility and consumability) to assess the shoot-level flammability of 21 species of Dracophyllum (Ericaceae). Using a macroevolutionary approach, we explored phylogenetic patterns of variation in shoot-level flammability. Shoot-level flammability varied widely in Dracophyllum. Species in the subgenus Oreothamnus had higher flammability and smaller leaves than those in the subgenus Dracophyllum. Shoot flammability (ignitability, combustibility and consumability) and leaf length showed phylogenetic conservatism across genus Dracophyllum, but exhibited lability among some closely related species, such as D. menziesii and D. fiordense. Shoot flammability of Dracophyllum species was negatively correlated with leaf length and shoot moisture content, but had no relationship with the geographic distribution of Dracophyllum species. Shoot-level flammability varied widely in the genus Dracophyllum, but showed phylogenetic conservatism. The higher flammability of the subgenus Oreothamnus may be an incidental or emergent property as a result of the evolution of flammability-related traits, such as smaller leaves, which were selected for other functions and incidentally changed flammability.

Shoot flammability of vascular plants is phylogenetically conserved and related to habitat fire-proneness and growth form.

Terrestrial plants and fire have interacted for at least 420 million years1. Whether recurrent fire drives plants to evolve higher flammability and what the evolutionary pattern of plant flammability is remain unclear2-7. Here, we show that phylogeny, the susceptibility of a habitat to have recurrent fires (that is, fire-proneness) and growth form are important predictors of the shoot flammability of 194 indigenous and introduced vascular plant species (Tracheophyta) from New Zealand. The phylogenetic signal of the flammability components and the variation in flammability among phylogenetic groups (families and higher taxonomic level clades) demonstrate that shoot flammability is phylogenetically conserved. Some closely related species, such as in Dracophyllum (Ericaceae), vary in flammability, indicating that flammability exhibits evolutionary flexibility. Species in fire-prone ecosystems tend to be more flammable than species from non-fire-prone ecosystems, suggesting that fire may have an important role in the evolution of plant flammability. Growth form also influenced flammability-forbs were less flammable than grasses, trees and shrubs; by contrast, grasses had higher biomass consumption by fire than other groups. The results show that shoot flammability of plants is largely correlated with phylogenetic relatedness, and high flammability may result in parallel evolution driven by environmental factors, such as fire regime.

Green firebreaks as a management tool for wildfires: Lessons from China.

Wildfire is a widespread natural hazard that is expected to increase in areal extent, severity and frequency with ongoing changes in climate and land-use. One tool that has been used in an effort to reduce the damage caused by wildfires is green firebreaks: strips of low-flammability vegetation grown at strategic locations in the landscape. Green firebreaks are increasingly being recommended for wildfire management and have been implemented in many countries. The approach is particularly widely used in China, where more than 364,000 km of green firebreaks have been planted and a further 167,000 km are planned for construction before 2025. China is not only a world leader in the implementation of green firebreaks but has also led the way in testing the effectiveness of green firebreaks and in providing guidelines for green firebreak construction. However, most of this research has been reported in the non-English literature, and so is inaccessible to many readers. Here we review the extensive research on the construction and effectiveness of green firebreaks in China and examine how the lessons learned from this research could contribute to the effective implementation of green firebreaks globally. Chinese studies suggest that the ideal species for green firebreaks should meet trait requirements from three perspectives: ecological, silvicultural and economic. Green firebreaks with a multi-layered structure and a closed canopy have the potential to be an effective, long-term, biodiversity-friendly and low-cost tool for fire suppression, although they complement rather than replace other more traditional fire suppression approaches.

Intergenerational Transmissions of Mother-Child Loneliness: A Moderated Mediation Model of Familial Social Support and Conflict Avoidance.

Loneliness is a psychological health issue related to deleterious physical health outcomes such as mortality and chronic disease. The aim of this research was to examine intergenerational transmissions of loneliness from mothers to adult child via a moderated mediation model of perceived familial social support and conflict avoidance. Surveys were collected from 146 (N = 292) mother-child dyads on self-reports of loneliness, familial social support, and mother-child conflict avoidance. The results showed that child perceptions of familial social support mediated the relationship between mother-child loneliness. Moreover, child reports of mother-child conflict avoidance moderated the path from familial social support to child loneliness. Specifically, children reported significantly higher levels of loneliness when they perceived low levels of familial social support and high levels of conflict avoidance. These findings expand research on the role of communicative mechanisms in parent-child transmissions of loneliness. The theoretical and practical implications are discussed in detail.

Src homology 2 domains enhance tyrosine phosphorylation in vivo by protecting binding sites in their target proteins from dephosphorylation.

Phosphotyrosine (pTyr)-dependent signaling is critical for many cellular processes. It is highly dynamic, as signal output depends not only on phosphorylation and dephosphorylation rates but also on the rates of binding and dissociation of effectors containing phosphotyrosine-dependent binding modules such as Src homology 2 (SH2) and phosphotyrosine-binding (PTB) domains. Previous in vitro studies suggested that binding of SH2 and PTB domains can enhance protein phosphorylation by protecting the sites bound by these domains from phosphatase-mediated dephosphorylation. To test whether this occurs in vivo, we used the binding of growth factor receptor bound 2 (GRB2) to phosphorylated epidermal growth factor receptor (EGFR) as a model system. We analyzed the effects of SH2 domain overexpression on protein tyrosine phosphorylation by quantitative Western and far-Western blotting, mass spectrometry, and computational modeling. We found that SH2 overexpression results in a significant, dose-dependent increase in EGFR tyrosine phosphorylation, particularly of sites corresponding to the binding specificity of the overexpressed SH2 domain. Computational models using experimentally determined EGFR phosphorylation and dephosphorylation rates, and pTyr-EGFR and GRB2 concentrations, recapitulated the experimental findings. Surprisingly, both modeling and biochemical analyses suggested that SH2 domain overexpression does not result in a major decrease in the number of unbound phosphorylated SH2 domain-binding sites. Our results suggest that signaling via SH2 domain binding is buffered over a relatively wide range of effector concentrations and that SH2 domain proteins with overlapping binding specificities are unlikely to compete with one another for phosphosites in vivo.

Revealing disease-associated pathways by network integration of untargeted metabolomics.

Uncovering the molecular context of dysregulated metabolites is crucial to understand pathogenic pathways. However, their system-level analysis has been limited owing to challenges in global metabolite identification. Most metabolite features detected by untargeted metabolomics carried out by liquid-chromatography-mass spectrometry cannot be uniquely identified without additional, time-consuming experiments. We report a network-based approach, prize-collecting Steiner forest algorithm for integrative analysis of untargeted metabolomics (PIUMet), that infers molecular pathways and components via integrative analysis of metabolite features, without requiring their identification. We demonstrated PIUMet by analyzing changes in metabolism of sphingolipids, fatty acids and steroids in a Huntington's disease model. Additionally, PIUMet enabled us to elucidate putative identities of altered metabolite features in diseased cells, and infer experimentally undetected, disease-associated metabolites and dysregulated proteins. Finally, we established PIUMet's ability for integrative analysis of untargeted metabolomics data with proteomics data, demonstrating that this approach elicits disease-associated metabolites and proteins that cannot be inferred by individual analysis of these data.

Time-resolved multimodal analysis of Src Homology 2 (SH2) domain binding in signaling by receptor tyrosine kinases.

While the affinities and specificities of SH2 domain-phosphotyrosine interactions have been well characterized, spatio-temporal changes in phosphosite availability in response to signals, and their impact on recruitment of SH2-containing proteins in vivo, are not well understood. To address this issue, we used three complementary experimental approaches to monitor phosphorylation and SH2 binding in human A431 cells stimulated with epidermal growth factor (EGF): 1) phospho-specific mass spectrometry; 2) far-Western blotting; and 3) live cell single-molecule imaging of SH2 membrane recruitment. Far-Western and MS analyses identified both well-established and previously undocumented EGF-dependent tyrosine phosphorylation and binding events, as well as dynamic changes in binding patterns over time. In comparing SH2 binding site phosphorylation with SH2 domain membrane recruitment in living cells, we found in vivo binding to be much slower. Delayed SH2 domain recruitment correlated with clustering of SH2 domain binding sites on the membrane, consistent with membrane retention via SH2 rebinding.

Early signaling dynamics of the epidermal growth factor receptor.

Despite extensive study of the EGF receptor (EGFR) signaling network, the immediate posttranslational changes that occur in response to growth factor stimulation remain poorly characterized; as a result, the biological mechanisms underlying signaling initiation remain obscured. To address this deficiency, we have used a mass spectrometry-based approach to measure system-wide phosphorylation changes throughout the network with 10-s resolution in the 80 s after stimulation in response to a range of eight growth factor concentrations. Significant changes were observed on proteins far downstream in the network as early as 10 s after stimulation, indicating a system capable of transmitting information quickly. Meanwhile, canonical members of the EGFR signaling network fall into clusters with distinct activation patterns. Src homology 2 domain containing transforming protein (Shc) and phosphoinositol 3-kinase (PI3K) phosphorylation levels increase rapidly, but equilibrate within 20 s, whereas proteins such as Grb2-associated binder-1 (Gab1) and SH2-containing tyrosine phosphatase (SHP2) show slower, sustained increases. Proximity ligation assays reveal that Shc and Gab1 phosphorylation patterns are representative of separate timescales for physical association with the receptor. Inhibition of phosphatases with vanadate reveals site-specific regulatory mechanisms and also uncovers primed activating components in the network, including Src family kinases, whose inhibition affects only a subset of proteins within the network. The results presented highlight the complexity of signaling initiation and provide a window into exploring mechanistic hypotheses about receptor tyrosine kinase (RTK) biology.

Measurement of Phosphorylated Peptides with Absolute Quantification.

Mass spectrometry, when coupled to on-line separation such as liquid chromatography or capillary electrophoresis, enables the identification and quantification of protein expression and post-translational modification changes under diverse conditions. To date most of the methods for mass spectrometry-based quantification have either provided relative quantification information (e.g., comparison to a selected condition) or utilized one-point calibration curves, or calibration curves in a different biological matrix. Although these quantitative methods have been used to generate insight into the differences between biological samples, additional biological insight could be gained by accurately measuring the absolute quantity of selected proteins and protein modifications. To address this challenge, we have developed the MARQUIS (Multiplex Absolute Regressed Quantification with Internal Standards) method, designed to provide absolute quantification for potentially hundreds of peptides across multiple samples in a single analysis, using a multi-point internal calibration curve derived from synthetic, isotopically distinct standard peptides.

Sexual Risk Among African American Women: Psychological Factors and the Mediating Role of Social Skills.

Prior research demonstrates a positive association between mental health problems and sexual risk for African American women. Using the social skills deficit hypothesis, we proposed that social skills mediate this relationship. African American women (n = 557, M age = 20.58) completed measures of depression, stress, emotional dysregulation, sexual risk behaviors, and perceptions of their social skills with their primary sexual partner. Social skills mediated the link between the mental health assessments and a composite sexual risk index. Theoretical implications of extending the social skill deficit hypothesis are discussed as well as implications for interventions.