10,568 research outputs found

    Increased Above-Ground Biomass and Plant Species Decline Related to the Presence of \u3ci\u3eEragrostis curvula\u3c/i\u3e across Multiple Grazing Grasslands in the Snowy Monaro Region of Australia

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    It will be noticed that invasions most often come to cultivated land, or to land much modified by human practice. This quote was published in 1958 by Charles Elton, and holds true today, backed by empirical evidence suggesting mechanisms of disturbance, plant functional traits and propagule pressure can push a cultivated system towards an invaded state. 17 farms, with either a current or previous history of grazing and land modification, within the Snowy Monaro Region, NSW, Australia, were surveyed to explore the relationship between the non-native C4 perennial tussock grass Eragrostis curvula [Schrad.] Nees. and species richness. As E. curvula increases above-ground biomass and proportion cover, we observed species richness declined within survey quadrats. E. curvula has the potential to outcompete desirable pasture species for vital resources, leading to a build-up of above-ground biomass and a decline in species richness. Impacts of E. curvula extent to the agricultural sector as graziers invest time, money and resources in management and supplementary feed. The data from this study was collected in 2019, a year impacted by drought leading to the onset of the black summer bushfires of early 2020. Therefore, this study\u27s findings need to be interpreted in the context of drought and may not accurately represent normal Snowy Monaro Region conditions. Nevertheless, E. curvula can be an undesirable pasture species that negatively impact agricultural and ecological values. The development of practical solutions to manage E. curvula has been shown to prevent secondary invasion of undesirable species through appropriate fire use, fertilizer application, appropriate grazing, and herbicide application. However, widespread adoption of these solutions needs to be implemented at a community scale instead of at an individual scale for effective long-term management

    Induced encystment improves resistance to preservation and storage of Acanthamoeba castellanii

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    Several conditions that allow the preservation, storage and rapid, efficient recovery of viable Acanthamoeba castellanii organisms were investigated. The viability of trophozoites (as determined by time to confluence) significantly declined over a period of 12 months when stored at −70°C using dimethyl sulfoxide (DMSO; 5 or 10%) as cryopreservant. As A. castellanii are naturally capable of encystment, studies were undertaken to determine whether induced encystment might improve the viability of organisms under a number of storage conditions. A. castellanii cysts stored in the presence of Mg2+ at 4°C remained viable over the study period, although time to confluence was increased from approximately 8 days to approximately 24 days over the 12-month period. Storage of cysts at −70°C with DMSO (5 or 10%) or 40% glycerol, but not 80% glycerol as cryopreservants increased their viability over the 12-month study period compared with those stored at room temperature. Continued presence of Mg2+ in medium during storage had no adverse effects and generally improved recovery of viable organisms. The present study demonstrates that A. castellanii can be stored as a non-multiplicative form inexpensively, without a need for cryopreservation, for at least 12 months, but viability is increased by storage at −70°C

    Eragrostis (Poaceae): Monophyly and Infrageneric Classification

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    Eragrostis is a large genus in subfamily Chloridoideae of Poaceae. Recent phylogenetic analyses have suggested that the genus may not be monophyletic, that some of its segregate genera may be better placed within Eragrostis, and that current infrageneric classiïŹcations may not represent monophyletic groups. We have used molecular sequence data from the plastid locus rps16 and the nuclear gene waxy from a broad sample of Eragrostis species and representatives of six of the seven segregate genera to address these issues. We found that Eragrostis is monophyletic with the inclusion of several of the segregates, including Acamptoclados, Diandrochloa, and Neeragrostis. The placement of Cladoraphis and Stiburus is uncertain. Thellungia does not belong in Eragrostis and is actually more closely related to Sporobolus. These data also suggest that existing infrageneric classiïŹcations are inadequate and do not correspond to monophyletic groups within Eragrostis

    A survey of the treatment and management of patients with severe chronic spontaneous urticaria.

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    Chronic spontaneous urticaria (CSU) is characterized by the recurrent appearance of weals, angio‐oedema or both, occurring at least twice weekly for longer than 6 weeks.1 It is often managed with antihistamines, but occasionally requires other systemic agents in recalcitrant cases. A cross‐sectional survey was conducted by means of an internet‐based survey tool (Typeform; https://www.typeform.com). Participating consultants with a specialist interest in urticaria were identified through the specialist registers of the British Society of Allergy and Clinical Immunology (BSACI), the Improving Quality in Allergy Services (IQAS) Group and the British Association of Dermatologists (BAD), and invited to take part. The survey content was based on current CSU treatment guidelines from EAACI/GA2LEN/EDF/WAO1 and the British Society for Allergy and Clinical Immunology (BSACI).2 The EAACI/GA2LEN/EDF/WAO guidelines are a joint initiative of the Dermatology Section of the European Academy of Allergy and Clinical Immunology (EAACI), the Global Allergy and Asthma European Network (GA2LEN) (a European Union‐funded network of excellence), the European Dermatology Forum (EDF), and the World Allergy Organization (WAO). To standardize responses, all participants were presented with a case of recalcitrant CSU (failed on maximum dose of nonsedating antihistamines and montelukast), requiring alternative systemic treatment. Questions covered usage of systemic treatments, routine disease severity assessments, adherence to treatment guidelines and perceived barriers to prescribing. Responses (Table 1) were received from 19 UK consultants (26 surveys sent; completion rate 73%), 15 of whom had > 10 years’ experience in the treatment of CSU. The majority were allergy (58%) and dermatology consultants (37%). Of the 19 consultants, 56% provide a dedicated urticaria service, 37% treat both adult and paediatric patients, and the majority (79%) use systemic medications other than antihistamines and montelukast. Omalizumab and ciclosporin were the most commonly used first‐line agents (47% and 27% respectively) (Fig. 1). The majority (84%) of consultants use validated measures to assess disease severity, including the weekly Urticaria Activity Score (UAS‐7, 63%), the Physician Global Assessment (63%), the Patient Global Assessment (44%) and the Dermatology Quality of Life Index (DLQI) (38%). Guidelines are used by 89% to direct their management of CSU, with 50% using the EAACI/GA2LEN/EDF/WAO guideline,1 compared with 31% primarily using the BSACI guideline.2 The main perceived barriers to prescribing systemic medications were potential adverse effects (AEs) (32% strongly agreed), potential long‐term toxicity (26% strongly agreed), cost of treatment (42% strongly agreed), and views expressed by the patient and their family (37% agreed)

    Determining ‘Wether’ Social Behaviour or Pasture Quality Drives Sheep Grazing Patterns using Random Forest Modelling

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    Monitoring livestock provides valuable insights into the spatial distribution, foraging patterns, and animal behaviour, which may lead to the improved management of livestock. This objective of study was to understand what variables were significant in determining where sheep spent the most time in paddocks of native (dominated by Poa spp., Stipa spp., and Hordeum leporinum), and improved (Phalaris aquatica, Festuca spp., and Trifolium subterraneum) pastures (~24 ha-1 in size). Castrated male sheep, wethers, were tracked using GPS collars on a property located in the Monaro region of Southern New South Wales, Australia. Trials were performed over four six-day periods in April, July, and November of 2014, and March in 2015. Thirty collars were randomly placed on 15 sheep in each pasture types. The GPS collars continuously recorded movements over the duration of each trial and were programmed to take five positional fixes over a minute. Data was analysed all together to understand various trends that may have occurred across the year, using random forest models (RFMs). Models were created for improved (IP) and native (NP) paddocks, producing R2 values of 0.97 and 0.94. Regardless of the pasture type, near distance to water (NW) was important in predicting where animals were located within paddocks, despite its statistical insignificance. Sheep spent more time further away from water troughs (at least ~600 m). Additionally, NDVI was another important variable in predicting sheep location for IP and NP (p \u3c 0.01). The data suggests that RFMs are able to predict where animals will likely spend time on a paddock at a large scale, with water troughs and pasture quality being two key drivers

    Hands-on Gravitational Wave Astronomy: Extracting astrophysical information from simulated signals

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    In this paper we introduce a hands-on activity in which introductory astronomy students act as gravitational wave astronomers by extracting information from simulated gravitational wave signals. The process mimics the way true gravitational wave analysis will be handled by using plots of a pure gravitational wave signal. The students directly measure the properties of the simulated signal, and use these measurements to evaluate standard formulae for astrophysical source parameters. An exercise based on the discussion in this paper has been written and made publicly available online for use in introductory laboratory courses.Comment: 5 pages, 4 figures; submitted to Am. J. Phy

    Kalinia, a New North American Genus for a Species Long Misplaced in Eragrostis (Poaceae, Chloridoideae)

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    Eragrostis obtusiflora (Poaceae, Chloridoideae), a species distributed from the southwestern United States to central Mexico, has long been recognized for exhibiting morphological and anatomical features atypical of Eragrostis. Phylogenetic analyses of nuclear internal transcribed spacer sequences and plastid sequences demonstrate that E. obtusiflora should be excluded from Eragrostis (Eragrostideae) and instead be placed in Cynodonteae, although its position within this tribe was unresolved. Additional data, including anatomical and micromorphological characters, suggest a close relationship with Distichlis. However, differences in spikelet and rhizome characters prevent its inclusion in Distichlis. Therefore, the species is transferred to a newly described genus, Kalinia, as K. obtusiflora
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