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Summary: Nutrient limitation may constrain the ability of recovering and mature tropical forests to serve as a carbon sink. However, it is unclear to what extent trees can utilize nutrient acquisition strategies – especially root phosphatase enzymes and mycorrhizal symbioses – to overcome low nutrient availability across secondary succession.Using a large‐scale, full factorial nitrogen and phosphorus fertilization experiment of 76 plots along a secondary successional gradient in lowland wet tropical forests of Panama, we tested the extent to which root phosphatase enzyme activity and mycorrhizal colonization are flexible, and if investment shifts over succession, reflective of changing nutrient limitation. We also conducted a meta‐analysis to test how tropical trees adjust these strategies in response to nutrient additions and across succession.We find that tropical trees are dynamic, adjusting investment in strategies – particularly root phosphatase – in response to changing nutrient conditions through succession. These changes reflect a shift from strong nitrogen to weak phosphorus limitation over succession. Our meta‐analysis findings were consistent with our field study; we found more predictable responses of root phosphatase than mycorrhizal colonization to nutrient availability.Our findings suggest that nutrient acquisition strategies respond to nutrient availability and demand in tropical forests, likely critical for alleviating nutrient limitation. [ABSTRACT FROM AUTHOR]

Tropical ecosystems face escalating global change. These shifts can disrupt tropical forests' carbon (C) balance and impact root dynamics. Since roots perform essential functions such as resource acquisition and tissue protection, root responses can inform about the strategies and vulnerabilities of ecosystems facing present and future global changes. However, root trait dynamics are poorly understood, especially in tropical ecosystems. We analyzed existing research on tropical root responses to key global change drivers: warming, drought, flooding, cyclones, nitrogen (N) deposition, elevated (e) CO2, and fires. Based on tree species‐ and community‐level literature, we obtained 266 root trait observations from 93 studies across 24 tropical countries. We found differences in the proportion of root responsiveness to global change among different global change drivers but not among root categories. In particular, we observed that tropical root systems responded to warming and eCO2 by increasing root biomass in species‐scale studies. Drought increased the root: shoot ratio with no change in root biomass, indicating a decline in aboveground biomass. Despite N deposition being the most studied global change driver, it had some of the most variable effects on root characteristics, with few predictable responses. Episodic disturbances such as cyclones, fires, and flooding consistently resulted in a change in root trait expressions, with cyclones and fires increasing root production, potentially due to shifts in plant community and nutrient inputs, while flooding changed plant regulatory metabolisms due to low oxygen conditions. The data available to date clearly show that tropical forest root characteristics and dynamics are responding to global change, although in ways that are not always predictable. This synthesis indicates the need for replicated studies across root characteristics at species and community scales under different global change factors. [ABSTRACT FROM AUTHOR]

Plant essential macronutrients like nitrogen (N) and phosphorus (P) can limit savanna tree growth and are important determinants of savanna vegetation dynamics, along with rainfall, fire and herbivory. How nitrogen and phosphorus shape tree‐grass competition and their coexistence remain unclear, hindering our ability to predict how savannas may respond to altered nutrient cycling.Here, we evaluate (1) if trees and grasses respond differently to N versus P availability, or (2) if grasses are more competitive in low nutrient environments while trees are more competitive in high nutrient environments. To do this, we grew saplings of 6 tree and 1 grass species from the Kruger National Park, South Africa, for 16 weeks under fully factorial nutrient and competition treatments (with/without competitors, low/high rate of N supply and low/high rate of P supply) under a watering regime designed to mimic wet season rainfall in a mesic savanna.Trees and grasses foraged most aggressively for nitrogen and allocated biomass differently depending on nitrogen availability. Overall, tree growth decreased in competition with grass, even in high nutrient environments where they grew faster. Grasses were always better below‐ground competitors, utilising aggressive nutrient foraging strategies, including high root phosphatase activity in response to nitrogen and large root biomass allocation.Synthesis. In low nutrient environments (e.g. on nutrient‐poor sandy soils), nutrients may limit tree growth. Nutrient rich environments enable tree growth, but grasses continue to compete effectively with trees. Understanding what this means for ecosystem responses to nutrient availability is not trivial, especially in the context of fire and herbivory. However, it is clear that soil nutrients likely affect tree and grass growth and competition in savannas, which suggests that future changes in nutrient cycling, such as N deposition, may have important effects on savanna vegetation. [ABSTRACT FROM AUTHOR]

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The role of manganese (Mn) in ecosystem carbon (C) biogeochemical cycling is gaining increasing attention. While soil Mn is mainly derived from bedrock, atmospheric deposition could be a major source of Mn to surface soils, with implications for soil C cycling. However, quantification of the atmospheric Mn cycle, which comprises emissions from natural (desert dust, sea salts, volcanoes, primary biogenic particles, and wildfires) and anthropogenic sources (e.g., industrialization and land-use change due to agriculture), transport, and deposition, remains uncertain. Here, we use compiled emission data sets for each identified source to model and quantify the atmospheric Mn cycle by combining an atmospheric model and in situ atmospheric concentration measurements. We estimated global emissions of atmospheric Mn in aerosols (<10 µm in aerodynamic diameter) to be 1,400 Gg Mn year-1. Approximately 31% of the emissions come from anthropogenic sources. Deposition of the anthropogenic Mn shortened Mn "pseudo" turnover times in 1-mthick surface soils (ranging from 1,000 to over 10,000,000 years) by 1-2 orders of magnitude in industrialized regions. Such anthropogenic Mn inputs boosted the Mn-to-N ratio of the atmospheric deposition in non-desert dominated regions (between 5 × 10-5 and 0.02) across industrialized areas, but that was still lower than soil Mnto-N ratio by 1-3 orders of magnitude. Correlation analysis revealed a negative relationship between Mn deposition and topsoil C density across temperate and (sub)tropical forests, consisting with atmospheric Mn deposition enhancing carbon respiration as seen in in situ biogeochemical studies. [ABSTRACT FROM AUTHOR]

This article explores the significance of studying tropical forests and their responses to global change. It emphasizes the unique characteristics of tropical forests and their crucial role in the global carbon cycle. The article calls for research and model development to better understand the changing nature of these forests. It also discusses the importance of large-scale global change experiments and cross-site comparisons, as well as the complexity of plant, soil, and microbial responses. The document further highlights the need for inclusivity, collaboration, standardization, and the incorporation of local knowledge and partnerships with local communities in tropical forest research. [Extracted from the article]

Objective: Participation in regular exercise among post-secondary students is often low. Our cross-sectional study aimed to assess exercise levels, perceived barriers/motivators to exercise, and knowledge and use of exercise resources in graduate students. Participants: We recruited graduate students across various disciplines at a large Canadian university. Methods: Participants (n = 540) completed an anonymous mixed methods online survey. Results: Approximately 11% of participants reported not participating in any form of weekly exercise, and only 9.4% met the Canadian Physical Activity Guidelines. The most common barrier and motivator to exercise was time commitment and improving physical health, respectively. Some participants were aware of available exercise services but most did not use them. Suggestions for improving services included having graduate-dedicated exercise space and resources. Conclusions: Low exercise participation among graduate students may be due to a lack of education of available resources or a lack of existing resources that meet their specific needs. [ABSTRACT FROM AUTHOR]

Soil carbon (C) sequestration in agricultural working lands via soil amendments and management practices is considered a relatively well‐tested and affordable approach for removing CO2 from the atmosphere. Carbon farming provides useful benefits for soil health, biomass production, and crop resilience, but the effects of different soil C sequestration approaches on the nitrogen (N) cycle remain controversial. While some C farming practices have been shown to reduce N fertilizer use in some cases, C farming could also impose an unwanted "N penalty" through which soil C gains can only be maintained with additional N inputs, thereby increasing N losses to the environment. We systematically reviewed meta‐analysis studies on the impacts of C farming on N cycling in agroecosystems and estimated the cumulative effect of several C farming practices on N cycling. We found that, on average, combined C farming practices significantly reduced nitrous oxide emissions and nitrate leaching from soils, thus inferring both N cycling and climate change benefits. In addition to more widely studied C farming practices that generate organic C, we also discuss silicate rock additions, which offer a pathway to inorganic C sequestration that does not require additional N inputs, framing important questions for future research. [ABSTRACT FROM AUTHOR]

Postdoctoral positions provide critical opportunities for early‐career ecologists to build transferable skills, knowledge, and networks that will prepare them for professional success. However, these positions often come with personal and professional challenges such as stress, isolation, and lack of agency. Here, we describe a peer‐led postdoc program we created to maximize benefits and minimize challenges while preparing ourselves for a wide range of possible future careers using our training and expertise in ecology. We also give recommendations for other postdocs and early‐career scientists in ecology and across science, technology, engineering, and mathematics fields seeking to build a similar program. [ABSTRACT FROM AUTHOR]

Accurately quantifying rates and patterns of biological nitrogen fixation (BNF) in terrestrial ecosystems is essential to characterize ecological and biogeochemical interactions, identify mechanistic controls, improve BNF representation in conceptual and numerical modelling, and forecast nitrogen limitation constraints on future carbon (C) cycling.While many resources address the technical advantages and limitations of different methods for measuring BNF, less systematic consideration has been given to the broader decisions involved in planning studies, interpreting data, and extrapolating results. Here, we present a conceptual and practical road map to study design, study execution, data analysis and scaling, outlining key considerations at each step.We address issues including defining N‐fixing niches of interest, identifying important sources of temporal and spatial heterogeneity, designing a sampling scheme (including method selection, measurement conditions, replication, and consideration of hotspots and hot moments), and approaches to analysing, scaling and reporting BNF. We also review the comparability of estimates derived using different approaches in the literature, and provide sample R code for simulating symbiotic BNF data frames and upscaling.Improving and standardizing study design at each of these stages will improve the accuracy and interpretability of data, define limits of extrapolation, and facilitate broader use of BNF data for downstream applications. We highlight aspects—such as quantifying scales of heterogeneity, statistical approaches for dealing with non‐normality, and consideration of rates versus ecological significance—that are ripe for further development. [ABSTRACT FROM AUTHOR]

Molybdenum (Mo) is a key cofactor in enzymes used for nitrogen (N) fixation and nitrate reduction, and the low availability of Mo can constrain N inputs, affecting ecosystem productivity. Natural atmospheric Mo aerosolization and deposition from sources such as desert dust, sea‐salt spray, and volcanoes can affect ecosystem function across long timescales, but anthropogenic activities such as combustion, motor vehicles, and agricultural dust have accelerated the natural Mo cycle. Here we combined a synthesis of global atmospheric concentration observations and modeling to identify and estimate anthropogenic sources of atmospheric Mo. To project the impact of atmospheric Mo on terrestrial ecosystems, we synthesized soil Mo data and estimated the global distribution of soil Mo using two approaches to calculate turnover times. We estimated global emissions of atmospheric Mo in aerosols (<10 μm in diameter) to be 23 Gg Mo yr−1, with 40%–75% from anthropogenic sources. We approximated that for the top meter of soil, Mo turnover times range between 1,000 and 1,000,000 years. In some industrialized regions, anthropogenic inputs have enhanced Mo deposition 100‐fold, lowering the soil Mo turnover time considerably. Our synthesis of global observational data, modeling, and a mass balance comparison with riverine Mo exports suggest that anthropogenic activity has greatly accelerated the Mo cycle, with potential to influence N‐limited ecosystems. Plain Language Summary: Molybdenum (Mo) is an essential trace element that is, important for terrestrial and aquatic ecosystems, as it is required for biological nitrogen fixation and uptake. Mo is carried in particles to the atmosphere from sources such as desert dust, sea spray, and volcanoes resulting in losses and sources to different ecosystems. Atmospheric Mo deposition is essential on long time scales for soils which have lost Mo due to soil weathering, with consequences for nitrogen cycling. Anthropogenic changes to the Mo cycle from combustion, motor vehicles, and agricultural dust, are likely to be large, and have more than doubled sources of Mo to the atmosphere. Locally, anthropogenic changes to Mo in industrialized regions can represent a 100‐fold increase in deposition, and may affect nitrogen cycling in nitrogen‐limited ecosystems. Key Points: We compiled atmospheric molybdenum (Mo) concentration data and compared observations to a three‐dimensional global atmospheric aerosol modelAnthropogenic activity has likely doubled atmospheric Mo globally, but with regional variationMo turnover time in soils ranges between 1,000 and 1,000,000 years, with the shortest times in dust source regions and industrialized areas [ABSTRACT FROM AUTHOR]

Purpose. To investigate outcome differences of intralesional triamcinolone acetonide (TA) injection for primary chalazia in children versus adults. Methods. A retrospective review of consecutive subjects with primary chalazion who received intralesional TA injection was conducted. A single investigator injected 0.05-0.15mL of TA (40mg/mL) intralesionally. Patients were stratified into the pediatric (<18 years old) and adult (≥ 18 years old) group. In both groups, the correlation of resolution time with chalazion size and TA dose was performed. Results. 17 children and 24 adults were enrolled, with a mean age of 7.4 ± 5.5 and 39.3 ± 16.7 years, respectively. Both groups had statistically similar baseline characteristics. There was no significant difference between the resolution time in the pediatric (18.2 ± 11.4 days) and adult (16.5 ± 11.0 days) group (P = 0.7). There were no significant complications from the TA injection. There was no significant correlation of resolution time to chalazion size (P = 0.7) nor TA dose (P = 0.3) in both groups. Conclusion. TA for the treatment of primary chalazion was equally effective in children and adults, without any significant complications, and the rate of clinical response did not appear to be dose-dependent. [ABSTRACT FROM AUTHOR]

Dementia literacy is important for risk mitigation and preventative strategies before disease onset. The aim of our study was to investigate dementia literacy and how demographic characteristics influence these perceptions in order to provide evidence for how dementia-centered public health initiatives should structure their focus. We conducted a globally administered online survey, through Amazon Mechanical Turk (mTurk). Survey items evaluated: (1) personal perception on the preventability of dementia, and (2) risk awareness of lifestyle factors. Differences in risk scoring between the 598 respondents were compared using Kruskal-Wallis testing factored by demographic categorizations. Most of the sample demonstrated understanding that lifestyle factors contribute some risk toward dementia, though these risk scores were generally low. Differences in risk scoring varied by demographic characteristics. Women, older adults, those with non-post-secondary attainment, below average income, and White background tended to report lower risk scores. Public health education and initiatives for dementia prevention should focus on lifestyle risk factors, in addition to considering the barriers related to the demographic factors identified that may prevent populations from accessing programs and information., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Horst, Furlano, Wong, Ford, Han and Nagamatsu.)

Purpose: To investigate outcome differences of intralesional triamcinolone acetonide (TA) injection for primary chalazia in children versus adults., Methods: A retrospective review of consecutive subjects with primary chalazion who received intralesional TA injection was conducted. A single investigator injected 0.05-0.15 mL of TA (40 mg/mL) intralesionally. Patients were stratified into the pediatric (<18 years old) and adult (≥ 18 years old) group. In both groups, the correlation of resolution time with chalazion size and TA dose was performed., Results: 17 children and 24 adults were enrolled, with a mean age of 7.4 ± 5.5 and 39.3 ± 16.7 years, respectively. Both groups had statistically similar baseline characteristics. There was no significant difference between the resolution time in the pediatric (18.2 ± 11.4 days) and adult (16.5 ± 11.0 days) group (P = 0.7). There were no significant complications from the TA injection. There was no significant correlation of resolution time to chalazion size (P = 0.7) nor TA dose (P = 0.3) in both groups., Conclusion: TA for the treatment of primary chalazion was equally effective in children and adults, without any significant complications, and the rate of clinical response did not appear to be dose-dependent.

Choroidal osteoma is an uncommon benign osseous intraocular tumor that typically affects young adult women. Choroidal neovascularization (CNV) is one of the complications that can develop in eyes with choroidal osteoma. We present a case of CNV secondary to choroidal osteoma treated with intravitreal ranibizumab. A 57-year-old lady presented with painless loss of vision with a right-eye visual acuity of 20/800. Fundus examination showed a well-demarcated yellowish peripapillary choroidal osteoma with associated retinal and subretinal hemorrhage due to CNV. Three intravitreal ranibizumab injections at monthly intervals were given and her visual acuity improved to 20/30 following treatment. After 1.2 years of follow-up, the right eye visual acuity was maintained at 20/30 with no evidence of CNV recurrence. Our findings suggest that intravitreal ranibizumab may be an effective therapeutic option for treating CNV secondary to choroidal osteoma.