The role of browsers in maintaining the openness of savanna grazing lawns

In savannas, ruminant herbivores can have divergent impacts on tree recruitment and subsequent woody cover. Whereas heavy grazing by cattle results in woody thickening, intensive grazing by wildlife instead tends to be associated with lower woody cover. To disentangle why woody cover is low in areas heavily grazed by wildlife, we investigated (a) whether grazing lawns attract indigenous mammalian browsers, and if a preference for short-grass habitat decreases with browser body mass as predator susceptibility decreases; and (b) whether browser attraction to grazing lawns translates into the suppression of woody plants, including seedlings and saplings, thus maintaining the openness of heavily grazed short-grass areas. In Kruger National Park, South Africa, we contrasted browser abundance (using dung counts) on grazing lawns and on low-herbivory sites characterised by tall grass. Additionally, a herbivore exclosure experiment was set up to investigate the combined impact of browser removal and grass height habitat type on seedling survival and sapling growth of a dominant woody plant species. Finally, in Hluhluwe-iMfolozi Park (HiP), we examined the long-term (10 years) impact of browser removal on the growth rates of a range of woody species, monitored across ten sites along a gradient of herbivory ranging from grazing lawn to tall grass. Steenbok and impala selected short- over tall grass as preferred browsing sites, while elephant preferred tall grass. Browser abundance on short grass decreased with browser body mass, indicating that predator avoidance might be a key factor driving mesoherbivores to utilise grazing lawns. Seedling survival was lowest on grazing lawns when browsers were present, with mortality occurring in two out of every three seedlings. Similarly, sapling growth was lowest on grazing lawns, although browser removal had no significant effect. Evidence for increased browser impact on grazing lawns was clearest from our long-term herbivore exclosure experiment in HiP, which demonstrated that browsers strongly modify the growth rates of woody plants in short-grass habitats. Synthesis. These results provide support for the hypothesis that browsers, particularly browsing mesoherbivores and mixed feeders, are attracted to short-grass habitats, and that they help maintain grazing lawn openness by suppressing seedling survival and woody plant growth where grass is kept short by grazers.SUPPORTING INFORMATION: Table S1. Proportion short grass calculated as the mean proportion of grass height below 10 cm, recorded at ten sites in HiP (Hluhluwe and iMfolozi Game Reserves). The mean number of grazer dung piles per year (species: buffalo, blue wildebeest, impala, warthog, white rhino and zebra) are shown for each site. Values in brackets represent standard errors.Figure S1. The effect of grass height and exclosure status (fenced vs. unfenced) on tree height gain (mean ± SE). Browsing impact on tree height gain was higher in areas with short grass i.e. browsers utilised trees in short-grass ecosystems more than in tall-grass ecosystems. Results of linear regression analyses are displayed for the unfenced treatment of two dominant woody plant species: a) D. cinerea (R2 = 0.38, p = 0.05) and b) A. nilotica (R2 = 0.44, p = 0.11), and for two woody plant functional types: c) fine-leaved (R2 = 0.33, p = 0.09) and d) broad-leaved (R2 = 0.60, p = 0.02), across 10 sites in Hluhluwe-iMfolozi Park for the period 2000-2009.DATA AVAILABILITY STATEMENT: Data are available from the Dryad Digital Repository https://doi-org.uplib.idm.oclc.org/10.5061/dryad.76hdr7st3 (Voysey et al., 2020).The USAID/NAS program ‘Partnerships for Enhanced Engagement in Research' (sub-grant 2000004946, Cycle 3) and the South African National Research Foundation, Department of Science and Technology, Innovation and Priority Research Masters Scholarship.http://www.wileyonlinelibrary.com/journal/jechj2022Plant Production and Soil Scienc

Anthropogenic modifications to fire regimes in the wider Serengeti‐Mara ecosystem

Fire is a key driver in savannah systems and widely used as a land management tool. Intensifying human land uses are leading to rapid changes in the fire regimes, with consequences for ecosystem functioning and composition. We undertake a novel analysis describing spatial patterns in the fire regime of the Serengeti‐Mara ecosystem, document multidecadal temporal changes and investigate the factors underlying these patterns. We used MODIS active fire and burned area products from 2001 to 2014 to identify individual fires; summarizing four characteristics for each detected fire: size, ignition date, time since last fire and radiative power. Using satellite imagery, we estimated the rate of change in the density of livestock bomas as a proxy for livestock density. We used these metrics to model drivers of variation in the four fire characteristics, as well as total number of fires and total area burned. Fires in the Serengeti‐Mara show high spatial variability—with number of fires and ignition date mirroring mean annual precipitation. The short‐term effect of rainfall decreases fire size and intensity but cumulative rainfall over several years leads to increased standing grass biomass and fuel loads, and, therefore, in larger and hotter fires. Our study reveals dramatic changes over time, with a reduction in total number of fires and total area burned, to the point where some areas now experience virtually no fire. We suggest that increasing livestock numbers are driving this decline, presumably by inhibiting fire spread. These temporal patterns are part of a global decline in total area burned, especially in savannahs, and we caution that ecosystem functioning may have been compromised. Land managers and policy formulators need to factor in rapid fire regime modifications to achieve management objectives and maintain the ecological function of savannah ecosystems

Large Scale Application of Neural Network Based Semantic Role Labeling for Automated Relation Extraction from Biomedical Texts

To reduce the increasing amount of time spent on literature search in the life sciences, several methods for automated knowledge extraction have been developed. Co-occurrence based approaches can deal with large text corpora like MEDLINE in an acceptable time but are not able to extract any specific type of semantic relation. Semantic relation extraction methods based on syntax trees, on the other hand, are computationally expensive and the interpretation of the generated trees is difficult. Several natural language processing (NLP) approaches for the biomedical domain exist focusing specifically on the detection of a limited set of relation types. For systems biology, generic approaches for the detection of a multitude of relation types which in addition are able to process large text corpora are needed but the number of systems meeting both requirements is very limited. We introduce the use of SENNA (“Semantic Extraction using a Neural Network Architecture”), a fast and accurate neural network based Semantic Role Labeling (SRL) program, for the large scale extraction of semantic relations from the biomedical literature. A comparison of processing times of SENNA and other SRL systems or syntactical parsers used in the biomedical domain revealed that SENNA is the fastest Proposition Bank (PropBank) conforming SRL program currently available. 89 million biomedical sentences were tagged with SENNA on a 100 node cluster within three days. The accuracy of the presented relation extraction approach was evaluated on two test sets of annotated sentences resulting in precision/recall values of 0.71/0.43. We show that the accuracy as well as processing speed of the proposed semantic relation extraction approach is sufficient for its large scale application on biomedical text. The proposed approach is highly generalizable regarding the supported relation types and appears to be especially suited for general-purpose, broad-scale text mining systems. The presented approach bridges the gap between fast, cooccurrence-based approaches lacking semantic relations and highly specialized and computationally demanding NLP approaches

Anthropogenic modifications to fire regimes in the wider Serengeti-Mara ecosystem

Fire is a key driver in savannah systems and widely used as a land management tool. Intensifying human land uses are leading to rapid changes in the fire regimes, with consequences for ecosystem functioning and composition. We undertake a novel analysis describing spatial patterns in the fire regime of the Serengeti‐Mara ecosystem, document multidecadal temporal changes and investigate the factors underlying these patterns. We used MODIS active fire and burned area products from 2001 to 2014 to identify individual fires; summarizing four characteristics for each detected fire: size, ignition date, time since last fire and radiative power. Using satellite imagery, we estimated the rate of change in the density of livestock bomas as a proxy for livestock density. We used these metrics to model drivers of variation in the four fire characteristics, as well as total number of fires and total area burned. Fires in the Serengeti‐Mara show high spatial variability—with number of fires and ignition date mirroring mean annual precipitation. The short‐term effect of rainfall decreases fire size and intensity but cumulative rainfall over several years leads to increased standing grass biomass and fuel loads, and, therefore, in larger and hotter fires. Our study reveals dramatic changes over time, with a reduction in total number of fires and total area burned, to the point where some areas now experience virtually no fire. We suggest that increasing livestock numbers are driving this decline, presumably by inhibiting fire spread. These temporal patterns are part of a global decline in total area burned, especially in savannahs, and we caution that ecosystem functioning may have been compromised. Land managers and policy formulators need to factor in rapid fire regime modifications to achieve management objectives and maintain the ecological function of savannah ecosystems.Natural Environment Research Council, Grant/Award Number: JZG10015; Leverhulme Trust, Grant/Award Number: IN‐2014‐022; Vetenskapsrådet; Sida and Formas, Grant/Award Number: 2016‐06355.http://wileyonlinelibrary.com/journal/gcbhj2019Zoology and Entomolog

Crowdsourcing to support training for public health: A scoping review

Crowdsourcing is an interactive process that has a group of individuals attempt to solve all or part of a problem and then share solutions with the public. Crowdsourcing is increasingly used to enhance training through developing learning materials and promoting mentorship. This scoping review aims to assess the literature on crowdsourcing for training in public health. We searched five medical and public health research databases using terms related to crowdsourcing and training. For this review, the concept of crowdsourcing included open calls, designathons, and other activities. We used a PRISMA checklist for scoping reviews. Each full-text was assessed by two independent reviewers. We identified 4,071 citations, and 74 studies were included in the scoping review. This included one study in a low-income country, 15 studies in middle-income countries, 35 studies in high-income countries, and 11 studies conducted in multiple countries of varying income levels (the country income level for 12 studies could not be ascertained). Nine studies used open calls, 35 used a hackathon, designathon or other “a-thon” event, and 30 used other crowdsourcing methods, such as citizen science programs and online creation platforms. In terms of crowdsourcing purpose, studies used crowdsourcing to educate participants (20 studies), develop learning materials (17 studies), enhance mentorship (13 studies) and identify trainees (9 studies). Fifteen studies used crowdsourcing for more than one training purpose. Thirty-four studies were done in-person, 31 were conducted virtually and nine used both meeting options for their crowdsourcing events. Seventeen studies generated open access materials. Our review found that crowdsourcing has been increasingly used to support public health training. This participatory approach can be a useful tool for training in a variety of settings and populations. Future research should investigate the impact of crowdsourcing on training outcomes

Youth engagement in HIV prevention intervention research in sub-Saharan Africa: a scoping review.

INTRODUCTION: Youth engagement in HIV research is generally recognized as essential, but often neglected or minimally implemented in practice. Engagement is a process of working collaboratively with diverse groups of people to address common issues. We conducted a scoping review of youth HIV prevention interventions in sub-Saharan Africa to identify and categorize forms and levels of youth engagement across the lifespan of intervention research. METHODS: We followed Arksey and O'Malley's framework for organizing a scoping review. We searched seven databases for related articles on identified intervention studies through May 28th 2020. Included studies focused on youth (10 to 24 years old) HIV prevention interventions in sub-Saharan Africa. Two reviewers independently examined citations and full manuscripts for inclusion. Data were extracted on study characteristics, location, description of youth engagement and extent of engagement. Youth engagement approaches were categorized based on Hart's ladder as substantial engagement (strong youth decision-making power), moderate engagement (shared decision making with adults), minimal engagement (no youth decision-making power) or no engagement. RESULTS: We identified 3149 citations and included 112 studies reporting on 74 unique HIV interventions. Twenty-two interventions were in low-income countries, 49 in middle-income countries, and three were in both. Overall, only nine interventions (12%) had substantial or moderate youth engagement, two-thirds (48, 65%) had minimal youth engagement and 17 interventions (23%) had no youth engagement. We also identified specific engagement strategies (e.g. youth-led research, crowdsourcing) that were feasible in multiple settings and resulted in substantial engagement. CONCLUSIONS: We found limited youth engagement in youth HIV prevention intervention studies in sub-Saharan Africa. However, several activities resulted in substantial youth engagement and could be relevant in many low-and-middle-income-country (LMIC) settings

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

A designathon to co-create community-driven HIV self-testing services for Nigerian youth: findings from a participatory event.

BACKGROUND: Youth are at high risk for HIV, but are often left out of designing interventions, including those focused on adolescents. We organized a designathon for Nigerian youth to develop HIV self-testing (HIVST) strategies for potential implementation in their local communities. A designathon is a problem-focused event where participants work together over a short period to create and present solutions to a judging panel. METHODS: We organized a 72-h designathon for youth (14-24 years old) in Nigeria to design strategies to increase youth HIVST uptake. Proposals included details about HIVST kit service delivery, method of distribution, promotional strategy, and youth audience. Teams pitched their proposals to a diverse seven-member judging panel who scored proposals based on desirability, feasibility, potential impact and teamwork. We examined participants' socio-demographic characteristics and summarized themes from their HIVST proposals. RESULTS: Forty-two youth on 13 teams participated in the designathon. The median team size was 3 participants (IQR: 2-4). The median age was 22.5 years (IQR: 21-24), 66.7% were male, 47.4% completed tertiary education, and 50% lived in Lagos State. Themes from proposals included HIVST integration with other health services, digital marketing and distribution approaches, and engaging students. Judges identified seven teams with exceptional HIVST proposals and five teams were supported for further training. CONCLUSIONS: The designathon provided a structured method for incorporating youth ideas into HIV service delivery. This approach could differentiate HIV services to be more youth-friendly in Nigeria and other settings

Distinguishing Characteristics between Pandemic 2009–2010 Influenza A (H1N1) and Other Viruses in Patients Hospitalized with Respiratory Illness

BACKGROUND: Differences in clinical presentation and outcomes among patients infected with pandemic 2009 influenza A H1N1 (pH1N1) compared to other respiratory viruses have not been fully elucidated. METHODOLOGY/PRINCIPAL FINDINGS: A retrospective study was performed of all hospitalized patients at the peak of the pH1N1 season in whom a single respiratory virus was detected by a molecular assay targeting 18 viruses/subtypes (RVP, Luminex xTAG). Fifty-two percent (615/1192) of patients from October, 2009 to December, 2009 had a single respiratory virus (291 pH1N1; 207 rhinovirus; 45 RSV A/B; 37 parainfluenza; 27 adenovirus; 6 coronavirus; and 2 metapneumovirus). No seasonal influenza A or B was detected. Individuals with pH1N1, compared to other viruses, were more likely to present with fever (92% & 70%), cough (92% & 86%), sore throat (32% & 16%), nausea (31% & 8%), vomiting (39% & 30%), abdominal pain (14% & 7%), and a lower white blood count (8,500/L & 13,600/L, all p-values<0.05). In patients with cough and gastrointestinal complaints, the presence of subjective fever/chills independently raised the likelihood of pH1N1 (OR 10). Fifty-five percent (336/615) of our cohort received antibacterial agents, 63% (385/615) received oseltamivir, and 41% (252/615) received steroids. The mortality rate of our cohort was 1% (7/615) and was higher in individuals with pH1N1 compared to other viruses (2.1% & 0.3%, respectively; p = 0.04). CONCLUSIONS/SIGNIFICANCE: During the peak pandemic 2009-2010 influenza season in Rhode Island, nearly half of patients admitted with influenza-like symptoms had respiratory viruses other than influenza A. A high proportion of patients were treated with antibiotics and pH1N1 infection had higher mortality compared to other respiratory viruses