430 research outputs found

    An Assessment of Young Cattle Behaviour and Welfare in a Virtual Fencing System

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    Virtual fencing is a novel technology which uses a combination of audio and electrical stimuli to contain grazing livestock within a GPS boundary. There are however some concerns around the use of such a technology and its potential effects on the behaviour and welfare of animals. To investigate this, 64 dairy-origin calves were assigned to one of two treatments in a randomised complete block design, with 4 groups of 8 calves per treatment. The two treatments were virtual fencing (VF) and electric fencing (EF). The experimental period lasted 31 days in total, consisting of a 10 day training period and a 21 day grazing period. Welfare and behaviour of the animals was measured using faecal cortisol metabolites, activity pedometers, and behavioural recordings. Virtual fence data denoting the number of audio and electrical stimuli delivered for each animal were also recorded. Results show that there was no significant difference in animal welfare and behaviour between EF and VF in the current study. Additionally, there was no significant difference in daily liveweight gain between treatments. In the VF animals the rate of electric pulses declined after an initial learning period however there was a significant degree of variation in the rate of learning between animals. Virtual fencing could therefore offer an alternative to physical fencing for grazing young cattle without negatively impacting animal behaviour or welfare. The individual animal variation in VF systems however warrants further study

    An Exposure of the Sangamon Soil in Southeastern Minnesota

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    A recent roadcut along County Road 18 in northeastern Houston County has exposed two variants of a morphologically well-expressed, Sangamon Soil. The paleosol is covered by the equivalent of the Roxana Silt, as defined in Illinois. The Farmdale Soil is developed into the Roxana Silt. The section is capped by late Wisconsinan Peoria Loess. The Sangamon Soil was developed into slope wash deposits composed of, or derived from, pre-Wisconsinan loess. No direct evidence of pre-Wisconsinan glacial till was found at the site. Two radiocarbon ages, one from the Ab horizon of the Sangamon Soil and one from the Ab horizon of the Farmdale Soil yield results of 25,690 and 23,760 respectively. These are minimum ages that suggest that the Roxana Silt buried the older Sangamon Soil prior to 26,000 radiocarbon years ago and that the Peoria Loess buried the Farmdale Soil by 24,000 radiocarbon years ago

    Sequencing identifies a distinct signature of circulating microRNAs in early radiographic knee osteoarthritis

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    OBJECTIVE: MicroRNAs act locally and systemically to impact osteoarthritis (OA) pathophysiology, but comprehensive profiling of the circulating miRNome in early vs late stages of OA has yet to be conducted. Sequencing has emerged as the preferred method for microRNA profiling since it offers high sensitivity and specificity. Our objective is to sequence the miRNome in plasma from 91 patients with early [Kellgren-Lawrence (KL) grade 0 or 1 (n = 41)] or late [KL grade 3 or 4 (n = 50)] symptomatic radiographic knee OA to identify unique microRNA signatures in each disease state. DESIGN: MicroRNA libraries were prepared using the QIAseq miRNA Library Kit and sequenced on the Illumina NextSeq 550.Counts were produced for microRNAs captured in miRBase and for novel microRNAs. Statistical, bioinformatics, and computational biology approaches were used to refine and interpret the final list of microRNAs. RESULTS: From 215 differentially expressed microRNAs (FDR \u3c 0.01), 97 microRNAs showed an increase or decrease in expression in ≥85% of samples in the early OA group as compared to the median expression in the late OA group. Increasing this threshold to ≥95%, seven microRNAs were identified: hsa-miR-335-3p, hsa-miR-199a-5p, hsa-miR-671-3p, hsa-miR-1260b, hsa-miR-191-3p, hsa-miR-335-5p, and hsa-miR-543. Four novel microRNAs were present in ≥50% of early OA samples and had 27 predicted gene targets in common with the prioritized set of predicted gene targets from the 97 microRNAs, suggesting common underlying mechanisms. CONCLUSION: Applying sequencing to well-characterized patient cohorts produced unbiased profiling of the circulating miRNome and identified a unique panel of 11 microRNAs in early radiographic knee OA

    A Class of Topological Actions

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    We review definitions of generalized parallel transports in terms of Cheeger-Simons differential characters. Integration formulae are given in terms of Deligne-Beilinson cohomology classes. These representations of parallel transport can be extended to situations involving distributions as is appropriate in the context of quantized fields.Comment: 41 pages, no figure

    Variations in Implementation of Specifications Grading in STEM Courses

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    Specifications grading is an assessment strategy based on mastery learning, clear learning objectives, and frequent evaluations and feedback. Twelve instructors at a southeastern four-year public college implemented the specifications grading method across eight discrete courses in four STEM areas. In this modified assessment strategy, the students controlled their grades through multiple attempts, with limitations, on assessments of course objectives. The instructors designed and executed specifications grading in unique ways that aligned with their content areas, teaching beliefs, and individual teaching styles. Preliminary observations suggest that, regardless of subject area, specifications grading can be used as an alternative to traditional assessment methodologies in STEM courses, regardless of the content area. In general, three major variations of implementation arose from this initial trial. Major differences and commonalities among these types are discussed as they relate to the course subject area in which they are used. The results of this work add a unique set of assessment practices to the current body of knowledge in that other practitioners may gain insight on variations of the specifications grading method that may be practical and applicable in their own classrooms

    The evolutionary ecology of complex lifecycle parasites: linking phenomena with mechanisms

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    Many parasitic infections, including those of humans, are caused by complex lifecycle parasites (CLPs): parasites that sequentially infect different hosts over the course of their lifecycle. CLPs come from a wide range of taxonomic groups-from single-celled bacteria to multicellular flatworms-yet share many common features in their life histories. Theory tells us when CLPs should be favoured by selection, but more empirical studies are required in order to quantify the costs and benefits of having a complex lifecycle, especially in parasites that facultatively vary their lifecycle complexity. In this article, we identify ecological conditions that favour CLPs over their simple lifecycle counterparts and highlight how a complex lifecycle can alter transmission rate and trade-offs between growth and reproduction. We show that CLPs participate in dynamic host-parasite coevolution, as more mobile hosts can fuel CLP adaptation to less mobile hosts. Then, we argue that a more general understanding of the evolutionary ecology of CLPs is essential for the development of effective frameworks to manage the many diseases they cause. More research is needed identifying the genetics of infection mechanisms used by CLPs, particularly into the role of gene duplication and neofunctionalisation in lifecycle evolution. We propose that testing for signatures of selection in infection genes will reveal much about how and when complex lifecycles evolved, and will help quantify complex patterns of coevolution between CLPs and their various hosts. Finally, we emphasise four key areas where new research approaches will provide fertile opportunities to advance this field

    Epidemiology of a Daphnia-Multiparasite System and Its Implications for the Red Queen

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    The Red Queen hypothesis can explain the maintenance of host and parasite diversity. However, the Red Queen requires genetic specificity for infection risk (i.e., that infection depends on the exact combination of host and parasite genotypes) and strongly virulent effects of infection on host fitness. A European crustacean (Daphnia magna) - bacterium (Pasteuria ramosa) system typifies such specificity and high virulence. We studied the North American host Daphnia dentifera and its natural parasite Pasteuria ramosa, and also found strong genetic specificity for infection success and high virulence. These results suggest that Pasteuria could promote Red Queen dynamics with D. dentifera populations as well. However, the Red Queen might be undermined in this system by selection from a more common yeast parasite (Metschnikowia bicuspidata). Resistance to the yeast did not correlate with resistance to Pasteuria among host genotypes, suggesting that selection by Metschnikowia should proceed relatively independently of selection by Pasteuria

    Red Queen Coevolution on Fitness Landscapes

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    Species do not merely evolve, they also coevolve with other organisms. Coevolution is a major force driving interacting species to continuously evolve ex- ploring their fitness landscapes. Coevolution involves the coupling of species fit- ness landscapes, linking species genetic changes with their inter-specific ecological interactions. Here we first introduce the Red Queen hypothesis of evolution com- menting on some theoretical aspects and empirical evidences. As an introduction to the fitness landscape concept, we review key issues on evolution on simple and rugged fitness landscapes. Then we present key modeling examples of coevolution on different fitness landscapes at different scales, from RNA viruses to complex ecosystems and macroevolution.Comment: 40 pages, 12 figures. To appear in "Recent Advances in the Theory and Application of Fitness Landscapes" (H. Richter and A. Engelbrecht, eds.). Springer Series in Emergence, Complexity, and Computation, 201
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