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- Beal, Jacob, et al.
(author)
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Robust estimation of bacterial cell count from optical density
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Journal article (peer-reviewed)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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- Brönnimann, Stefan, et al.
(author)
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Unlocking Pre-1850 Instrumental Meteorological Records : A Global Inventory
- 2019
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In: Bulletin of The American Meteorological Society - (BAMS). - 0003-0007 .- 1520-0477. ; 100:12, s. ES389-ES413
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Journal article (peer-reviewed)abstract
- Instrumental meteorological measurements from periods prior to the start of national weather services are designated early instrumental data. They have played an important role in climate research as they allow daily to decadal variability and changes of temperature, pressure, and precipitation, including extremes, to be addressed. Early instrumental data can also help place twenty-first century climatic changes into a historical context such as defining preindustrial climate and its variability. Until recently, the focus was on long, high-quality series, while the large number of shorter series (which together also cover long periods) received little to no attention. The shift in climate and climate impact research from mean climate characteristics toward weather variability and extremes, as well as the success of historical reanalyses that make use of short series, generates a need for locating and exploring further early instrumental measurements. However, information on early instrumental series has never been electronically compiled on a global scale. Here we attempt a worldwide compilation of metadata on early instrumental meteorological records prior to 1850 (1890 for Africa and the Arctic). Our global inventory comprises information on several thousand records, about half of which have not yet been digitized (not even as monthly means), and only approximately 20% of which have made it to global repositories. The inventory will help to prioritize data rescue efforts and can be used to analyze the potential feasibility of historical weather data products. The inventory will be maintained as a living document and is a first, critical, step toward the systematic rescue and reevaluation of these highly valuable early records. Additions to the inventory are welcome.
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- Eeraerts, Maxime, et al.
(author)
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Pollination deficits and their relation with insect pollinator visitation are cultivar-dependent in an entomophilous crop
- 2024
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In: Agriculture, Ecosystems and Environment. - 0167-8809. ; 369
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Journal article (peer-reviewed)abstract
- Insects contribute considerably to global crop pollination, with pollination deficits being documented for multiple entomophilous or pollinator-dependent crops. Different cultivars of crops are being cultivated within and across production regions, so it is essential to understand the cultivar variability of pollination deficits. Here, we used a dataset from 286 sites from multiple production regions to develop a synthesis on pollination deficits in two widely cultivated highbush blueberry cultivars, ‘Bluecrop’ and ‘Duke’. Additionally, we determined if bee visitation or bee richness reduces pollination deficits in these cultivars. On average, neither cultivar showed pollination deficits regarding fruit set. However, for ‘Bluecrop’ we found pollination deficits for berry weight and seed set, which was not the case for ‘Duke’. Increasing total bee visitation reduced pollination deficits of both berry weight and seed set for ‘Bluecrop’. More specifically, a non-linear, negative exponential model best predicted this relation between bee visitation and pollination deficits. Our results highlight that pollination deficits and responses to pollinator visitation are variable between different cultivars of a single crop, which suggests opportunities to use certain cultivars that are less dependent on insect-mediated pollination in landscapes and regions where pollination services have been compromised. In addition, the non-linear response between bee visitation and pollination deficits suggests that optimal bee visitation rates need to be determined to improve pollination management and crop yield and to support accurate economic valuations of pollination services.
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4. |
- Eeraerts, Maxime, et al.
(author)
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Synthesis of highbush blueberry pollination research reveals region-specific differences in the contributions of honeybees and wild bees
- 2023
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In: Journal of Applied Ecology. - 0021-8901. ; 60:12, s. 2528-2539
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Research review (peer-reviewed)abstract
- Highbush blueberry production has expanded worldwide in recent decades. To safeguard future yields, it is essential to understand if insect pollination is limiting current blueberry production and which insects contribute to pollination in different production regions. We present a systematic review including a set of meta-analyses on insect-mediated pollination in highbush blueberry. We summarize the geographic distribution of research, the abundance of different pollinator taxa and their relative pollination contributions. Using raw data from 21 studies, totalling 496 site replicates, we determine the degree of pollination service and pollen limitation (i.e. combining open pollination levels with experimental bagged and/or hand pollination treatments), as well as the contribution of honeybees and wild bees to pollination (i.e. observational, open pollination). Most studies originate from North America, focusing on only a few cultivars. Honeybees are the dominant pollinator, and wild bees are occasionally abundant. Wild bees are more efficient pollinators on a single-visit basis compared to honeybees, which increases their relative pollination contribution compared to their relative abundance. Insect-mediated pollination services increased blueberry fruit set, berry weight and seed set (R2 values: 64.8%, 75.9% and 75.2% respectively). We often detected pollen limitation, indicated by an increase in fruit set, berry weight and seed set (R2: 10.1%, 18.2% and 21.5%, respectively), with additional hand pollination. Increasing visitation of honeybees and wild bees contributed to blueberry pollination by increasing fruit set (R2: 5.4% and 3.5%), berry weight (R2: 6.5% and 2.8%) and seed set (R2: 6.4% and 3.8%) respectively. Bee contributions to fruit set and berry weight were variable across regions. Synthesis and application: A diverse community of insects, primarily bees, contributes to highbush blueberry pollination and yield. However, pollination deficits are common. The finding that both honeybees and wild bees enhance pollination highlights the possibility of adopting different management strategies that utilize honeybees, wild bees or both depending on the specific context and region. This further emphasizes the general importance of conserving pollinator health and diversity. Our synthesis highlights data gaps and areas for future research to better understand the pollination contribution of different pollinators to crops that are expanding globally.
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5. |
- Hesketh, Kylie D., et al.
(author)
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Protocol for the Lets Grow randomised controlled trial : examining efficacy, cost-effectiveness and scalability of a m-Health intervention for movement behaviours in toddlers
- 2022
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In: BMJ Open. - : BMJ Publishing Group. - 2044-6055. ; 12:3
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Journal article (peer-reviewed)abstract
- Introduction Despite being an important period for the development of movement behaviours (physical activity, sedentary behaviour and sleep), few interventions commencing prior to preschool have been trialled. The primary aim of this trial is to assess the 12-month efficacy of the Lets Grow mHealth intervention, designed to improve the composition of movement behaviours in children from 2 years of age. Lets Grow is novel in considering composition of movement behaviours as the primary outcome, using non-linear dynamical approaches for intervention delivery, and incorporating planning for real-world implementation and scale-up from its inception. Methods and analysis A randomised controlled trial will test the effects of the 12-month parental support mHealth intervention, Lets Grow, compared with a control group that will receive usual care plus electronic newsletters on unrelated topics for cohort retention. Lets Grow will be delivered via a purpose-designed mobile web application with linked SMS notifications. Intervention content includes general and movement-behaviour specific parenting advice and incorporates established behaviour change techniques. Intervention adherence will be monitored by app usage data. Data will be collected from participants using 24-hour monitoring of movement behaviours and parent report at baseline (T-0), mid-intervention (T-1; 6 months post baseline), at intervention conclusion (T-2; 12 months post baseline) and 1-year post intervention (T-3; 2 years post baseline). The trial aims to recruit 1100 families from across Australia during 2021. In addition to assessment of efficacy, an economic evaluation and prospective scalability evaluation will be conducted. Ethics and dissemination The study was approved by the Deakin University Human Ethics Committee (2020-077). Study findings will be disseminated through publication in peer-reviewed journals, presentation at scientific and professional conferences, and via social and traditional media.
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6. |
- Keogan, Katharine, et al.
(author)
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Global phenological insensitivity to shifting ocean temperatures among seabirds
- 2018
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In: Nature Climate Change. - : Springer Science and Business Media LLC. - 1758-678X .- 1758-6798. ; 8:4, s. 313-318
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Journal article (peer-reviewed)abstract
- Reproductive timing in many taxa plays a key role in determining breeding productivity(1), and is often sensitive to climatic conditions(2). Current climate change may alter the timing of breeding at different rates across trophic levels, potentially resulting in temporal mismatch between the resource requirements of predators and their prey(3). This is of particular concern for higher-trophic-level organisms, whose longer generation times confer a lower rate of evolutionary rescue than primary producers or consumers(4). However, the disconnection between studies of ecological change in marine systems makes it difficult to detect general changes in the timing of reproduction(5). Here, we use a comprehensive meta-analysis of 209 phenological time series from 145 breeding populations to show that, on average, seabird populations worldwide have not adjusted their breeding seasons over time (-0.020 days yr(-1)) or in response to sea surface temperature (SST) (-0.272 days degrees C-1) between 1952 and 2015. However, marked between-year variation in timing observed in resident species and some Pelecaniformes and Suliformes (cormorants, gannets and boobies) may imply that timing, in some cases, is affected by unmeasured environmental conditions. This limited temperature-mediated plasticity of reproductive timing in seabirds potentially makes these top predators highly vulnerable to future mismatch with lower-trophic-level resources(2).
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