34 research outputs found

    Soil Fungi and the Effects of an Invasive Forb on Grasses: Neighbor Identity Matters

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    We studied the effects of soil fungi on interactions between Centaurea melitensis, an exotic invasive weed in central California, and two co-occurring grasses, Nassella pulchra and Avena barbata. The fungicide benomyl reduced the abundance of arbuscular mycorrhizal (AM) fungi in plant roots but did not affect non-AM fungi. Centaurea plants grown alone were \u3e50% smaller with the resident microbial community intact than when benomyl was applied. When grown with Nassella, the effect of benomyl was reversed. Centaurea grew almost five times larger with the resident microbial community intact. Fungicide had no effect on the biomass of Centaurea grown with Avena, but biomass of Centaurea was significantly lower when grown with Avena than when grown with Nassella or alone. Photosynthetically fixed carbon may have been transferred from Nassella via soil fungi to Centaurea, constituting a form of soil fungi-mediated parasitism, but such a transfer did not occur from Avena to Centaurea. Second, Nassella may have been more inhibited by soil pathogens in the presence of Centaurea than when alone, and the inhibition of Nassella may have released Centaurea from competition. A third possibility is that Nassella has strong positive effects on the growth of soil fungi, but the positive feedback of beneficial soil fungi to Nassella is less than the positive feedback to Centaurea. Regardless of the mechanism, the difference in soil fungicide treatment effects on competition between Centaurea and Nassella vs. Centaurea and Avena has important implications for the invasion of California grasslands

    Fostering purposeful engagement by building staff-student communities

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    In response to the Covid-19 pandemic, many universities moved to a blended delivery of online and in-person teaching. While necessary for public health, this significant disruption to education risked greater isolation and anxiety for students with the potential for less engagement and, consequently, reduced confidence in their abilities. However, it also presented an opportunity to re-evaluate practice and take steps to create new staff-student communities with potential to shape student engagement.The School of Mathematical Sciences at the University of Nottingham took several approaches to preserve and enhance student engagement, such as induction processes to foster new online communities, initiatives to boost academic and social interaction, development of close partnerships between staff and students in shaping the pandemic response, and the creation of an online staff community to discuss pedagogic practice and share training resources. The effectiveness of these approaches has been evaluated throughout the pandemic via staff-student meetings, module evaluation surveys and staff surveys.More than half the cohort joined an online student forum showing students appreciated online social interaction. However, for studying, students engaged in new one-to-one study-buddy and peer-mentoring schemes which students reported reduced their isolation and anxiety associated with online learning. Students reported online discussion forums to be one of the most useful tools for online learning. They liked being able to ask questions anonymously, in a forum where the lecturer was also present, something they could not do previously with in-person teaching. However, many students reported difficulty with managing their time because of increased asynchronous learning activity indicating a need for students to be trained in how to engage with online studying.Most staff have adopted elements of flipped learning to maximise student-student and student-staff interaction in the limited contact time. Staff engagement in their online community was strong, with most staff attending workshops and training sessions regarding online teaching. Consequently, staff were able to rapidly trial and share approaches that successfully addressed student feedback and promoted interaction

    The impact of peer assessment on mathematics students’ understanding of marking criteria and their ability to self-regulate learning

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    At the University of Nottingham peer-assessment was piloted with the objective of assisting students to gain greater understanding of marking criteria so that students may improve their comprehension of, and solutions to, future mathematical tasks. The study resulted in improvement in all four factors of observation, emulation, self-control and self-regulation thus providing evidence of a positive impact on student learning.The pilot involved a large first-year mathematics class who completed a formative piece of coursework prior to a problem class. At the problem class students were trained in the use of marking criteria before anonymously marking peer work. The pilot was evaluated using questionnaires (97 responses) at the beginning and end of the problem class. The questionnaires elicited students’ understanding of criteria before and after the task and students’ self-efficacy in relation to assessment self-control and self-regulation.The analysis of students’ descriptions of the criteria of assessment show that their understanding of the requirements for the task were expanded. After the class, explanation of the method and notation (consistent and correct) were much more present in students’ descriptions. Furthermore, 67 per cent of students stated they had specific ideas on how to improve their solutions to problems in the future. Students’ self-perceived abilities to self-assess and improve were positively impacted. The pilot gives strong evidence for the use of peer-assessment to develop students’ competencies as assessors, both in terms of their understanding of marking criteria and more broadly their ability to self-assess and regulate their learning

    Steering Mirror System with Closed-Loop Feedback for Free-Space Optical Communication Terminals

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    Precision beam pointing plays a critical role in free-space optical communications terminals in uplink, downlink and inter-satellite link scenarios. Among the various methods of beam steering, the use of fast steering mirrors (FSM) is widely adopted, with many commercial solutions employing diverse technologies, particularly focusing on small, high-bandwidth mirrors. This paper introduces a method using lightweight, commercial off-the-shelf components to construct a custom closed-loop steering mirror platform, suitable for mirror apertures exceeding 100 mm. The approach involves integrating optical encoders into two off-the-shelf open-loop actuators. These encoders read the signal reflected on purposefully diamond-machined knurled screw knobs, providing maximum contrast between light and dark lines. The resulting steering mirror has the potential to complement or replace FSM in applications requiring a larger stroke, at the expense of motion speed. In the presented setup, the mirror tilt resolution achieved based on the encoder closed-loop signal feedback is 45 μrad, with a mean slew rate of 1.5 mrad/s. Importantly, the steering assembly is self-locking, requiring no power to maintain a steady pointing angle. Using the mirror to actively correct for a constantly moving incoming beam, a 5-fold increase in concentration of the beam spot on the center of the detector was obtained compared to a fixed position mirror, demonstrating the mirrors ability to correct for satellite platform jitter and drift

    eMouseAtlas, EMAGE, and the spatial dimension of the transcriptome

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    Abstract eMouseAtlas (www.emouseatlas.org) is a com-prehensive online resource to visualise mouse development and investigate gene expression in the mouse embryo. We have recently deployed a completely redesigned Mouse Anatomy Atlas website (www.emouseatlas.org/emap/ema) that allows users to view 3D embryo reconstructions, delineated anatomy, and high-resolution histological sec-tions. A new feature of the website is the IIP3D web tool that allows a user to view arbitrary sections of 3D embryo reconstructions using a web browser. This feature provides interactive access to very high-volume 3D images via a tiled pan-and-zoom style interface and circumvents the need to download large image files for visualisation. eMouseAtla

    Cannabidiol and palmitoylethanolamide are anti-inflammatory in the acutely inflamed human colon

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    Objective: We sought to quantify the anti-inflammatory effects of two cannabinoid drugs, cannabidiol (CBD) and palmitoylethanolamide (PEA), in cultured cell lines and compared this effect with experimentally inflamed explant human colonic tissue. These effects were explored in acutely and chronically inflamed colon, using inflammatory bowel disease and appendicitis explants. Design: Caco-2 cells and human colonic explants collected from elective bowel cancer, inflammatory bowel disease (IBD) or acute appendicitis resections, and were treated with the following drug treatments: vehicle, an inflammatory protocol of interferon γ (IFNγ) and tumour necrosis factor α (TNFα; 10 ng/ml), inflammation and PEA (10 µM), inflammation and CBD (10 µM), and PEA or CBD alone, CBD or vehicle were added simultaneously with IFNγ. Nine intracellular signalling phosphoproteins were determined by multiplex. Inflammatory cytokine secretion was determined using ELISA. Receptor mechanisms were investigated using antagonists for CB1, CB2, PPARα, PPARγ, TRPV1 and GPR55. Results: IFNγ and TNFα treatment increased phosphoprotein and cytokine levels in Caco-2 cultures and colonic explants. Phosphoprotein levels were significantly reduced by PEA or CBD in Caco-2 cultures and colonic explants. CBD and PEA prevented increases in cytokine production in explant colon, but not in Caco-2 cells. CBD effects were blocked by the CB2 antagonist AM630 and TRPV1 antagonist SB366791. PEA effects were blocked by the PPARα antagonist GW6471. PEA and CBD were anti- inflammatory in IBD and appendicitis explants. Conclusion: PEA and CBD are anti-inflammatory in the human colon. This effect is not seen in cultured epithelial cells. Appropriately sized clinical trials should assess their efficac

    SARS-CoV-2 susceptibility and COVID-19 disease severity are associated with genetic variants affecting gene expression in a variety of tissues

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    Variability in SARS-CoV-2 susceptibility and COVID-19 disease severity between individuals is partly due to genetic factors. Here, we identify 4 genomic loci with suggestive associations for SARS-CoV-2 susceptibility and 19 for COVID-19 disease severity. Four of these 23 loci likely have an ethnicity-specific component. Genome-wide association study (GWAS) signals in 11 loci colocalize with expression quantitative trait loci (eQTLs) associated with the expression of 20 genes in 62 tissues/cell types (range: 1:43 tissues/gene), including lung, brain, heart, muscle, and skin as well as the digestive system and immune system. We perform genetic fine mapping to compute 99% credible SNP sets, which identify 10 GWAS loci that have eight or fewer SNPs in the credible set, including three loci with one single likely causal SNP. Our study suggests that the diverse symptoms and disease severity of COVID-19 observed between individuals is associated with variants across the genome, affecting gene expression levels in a wide variety of tissue types

    A first update on mapping the human genetic architecture of COVID-19

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    TANK-Binding Kinase 1-Dependent Responses in Health and Autoimmunity

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    The pathogenesis of autoimmune diseases, such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) is driven by genetic predisposition and environmental triggers that lead to dysregulated immune responses. These include the generation of pathogenic autoantibodies and aberrant production of inflammatory cytokines. Current therapies for RA and other autoimmune diseases reduce inflammation by targeting inflammatory mediators, most of which are innate response cytokines, resulting in generalized immunosuppression. Overall, this strategy has been very successful, but not all patients respond, responses can diminish over time and numerous side effects can occur. Therapies that target the germinal center (GC) reaction and/or antibody-secreting plasma cells (PC) potentially provide a novel approach. TANK-binding kinase 1 (TBK1) is an IKK-related serine/threonine kinase best characterized for its involvement in innate antiviral responses through the induction of type I interferons. TBK1 is also gaining attention for its roles in humoral immune responses. In this review, we discuss the role of TBK1 in immunological pathways involved in the development and maintenance of antibody responses, with particular emphasis on its potential relevance in the pathogenesis of humoral autoimmunity. First, we review the role of TBK1 in the induction of type I IFNs. Second, we highlight how TBK1 mediates inducible T cell co-stimulator signaling to the GC T follicular B helper population. Third, we discuss emerging evidence on the contribution of TBK1 to autophagic pathways and the potential implications for immune cell function. Finally, we discuss the therapeutic potential of TBK1 inhibition in autoimmunity
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