1,384 research outputs found

    Supplementary publications presented by Mr J. M. Stagg for the degree of D.Sc.

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    Volume 01 | BRITISH POLAR YEAR EXPEDITION FORT RAE, N.W. CANADA 1932-33 VOLUME I | DISCUSSION OF RESULTSVolume 02 | BRITISH POLAR YEAR EXPEDITION FORT RAE, N.W. CANADA 1932-33 VOLUME II | TABLESVolume 03 | 01. Some General Characteristics of Aurora at Fort Rae N.W. Canada 1932-33 | 02. NUMERICAL CHARACTER FIGURES OF MAGNETIC DISTURBANCE IN RELATION TO GEOMAGNETIC LATITUDE | 03. .Aspects of the Current System Producing Magnetic Disturbance | 04. The Diurnal Variation of Magnetic Disturbance in High Latitudes | 05. On the Variability of the Quiet -Day Diurnal Magnetic Variation at Eskdalemuir and Greenwich. By S. CHAPMAN, F.R.S., AND J. M. STAGG. | 06. On the Variability of the Quiet -Day Diurnal Magnetic Variation. Part II. BY S. CHAPMAN, F.R.S., AND J. M. STAGG. | 07. On the Variability of the Quiet -Day Diurnal Magnetic Variation. Part II. BY S. CHAPMAN, F.R.S., AND J. M. STAGG. | 08. Hourly Character Figures of Magnetic Disturbance at Kew Observatory, Richmond 1913-23 | 09. The Time Interval BETWEEN Magnetic Disturbance AND Associated Sunspot Changes | 10. THE ABSOLUTE DAILY RANGE OF MAGNETIC DECLINATION AT KEW OBSERVATORY, RICHMOND, 1901 to 1910 | 11. On Magnetic Fluctuations and Sunspot Frequency: A Discussion based primarily on the daily ranges of Declination as recorded at Kew Observatory, Richmond, during the 67 years 1858-1924 | 12. The 27-Day Recurrence Interval in Magnetic Disturbance: An Examination made with the aid of hourly Character Figures

    Shipping and the Spread of Infectious Salmon Anemia in Scottish Aquaculture

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    Long-distance transport of pathogens plays a critical role in the emergence of novel diseases. Shipping is a major contributor to such transport, and the role of ships in spreading disease has been recognized for centuries. However, statistical confirmation of pathogen spread by shipping is usually impractical. We present evidence of invasive spread of infectious salmon anemia in the salmon farms of Scotland and demonstrate a link between vessel visits and farm contamination. The link is associated with vessels moving fish between sites and transporting harvest, but not with vessels delivering food or involved in other work

    The structures of natively assembled clathrin-coated vesicles

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    Clathrin-coated vesicles mediate trafficking of proteins and nutrients in the cell and between organelles. Proteins included in the clathrin-coated vesicles (CCVs) category include clathrin heavy chain (CHC), clathrin light chain (CLC), and a variety of adaptor protein complexes. Much is known about the structures of the individual CCV components, but data are lacking about the structures of the fully assembled complexes together with membrane and in complex with cargo. Here, we determined the structures of natively assembled CCVs in a variety of geometries. We show that the adaptor β2 appendages crosslink adjacent CHC β-propellers and that the appendage densities are enriched in CCV hexagonal faces. We resolve how adaptor protein 2 and other associated factors in hexagonal faces form an assembly hub with an extensive web of interactions between neighboring β-propellers and propose a structural model that explains how adaptor binding can direct the formation of pentagonal and hexagonal faces

    Hunting for answers: Linking lectures with the real world using a mobile treasure hunt app

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    Plants underpin our society providing food, fuel, medicines, clean air and water, positive mental health, and are central to biodiversity conservation. Despite this importance and an increasing need for people with plant-identification skills, many societies are becoming increasingly ignorant to the species with which they interact. To benefit both our undergraduates and the society they will enter, we applied mobile technology to improve plant identification and appreciation , while providing opportunities to practice transferable team work and verbal communication skills. Encouraging 'plant vision' will improve conservation efforts while increasing personal connections with green spaces, leading to mental health improvements for society. Summary • Despite the importance of plants to human civilization, many societies are becoming increasingly ignorant to the plants that inhabit their surrounding environment. A phenomenon known as 'plant blindness'. To address plant blindness in undergraduate students we designed an outdoor activity using a mobile phone app. Our aims were to identify the level of 'plant blindness' in our students; investigate engagement with the app and activity ; determine if we can raise awareness of links between lecture content and real world scenarios; and assess the student experience as a result of the activity in large classes. • The app chosen was ActionBound. Students were asked to find and photograph local examples of four plant families, along with identifying physiological benefits of features covered in lectures. Two different first year classes were exposed to this activity-Plant Science and Life on Earth. • The Plant Science students (60% success rate for three families; 55 students) were less plant blind than Life on Earth students (less than 44% success rate in any of the four families; 200 students). Students engaged well with the activity with all groups submitting sensible attempts at the responses. Most students reported that the activity increased links to lecture material and all but one student reported positive experiences. • Our students found the treasure hunt learning environment is a fun way to engage with the plant topics covered in lectures. In future iterations, we will more explicitly explain the links to potential careers and will address some of the logistical challenges faced in this first cohort. K E Y W O R D S collaborative learning, fun learning, inclusivity, large classes, mobile learning, plant blindness, situational learning, treasure hun

    Integrating Remote Sensing with Ground-based Observations to Quantify the Effects of an Extreme Freeze Event on Black Mangroves (Avicennia germinans) at the Landscape Scale

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    Climate change is altering the frequency and intensity of extreme weather events. Quantifying ecosystem responses to extreme events at the landscape scale is critical for understanding and responding to climate-driven change but is constrained by limited data availability. Here, we integrated remote sensing with ground-based observations to quantify landscape-scale vegetation damage from an extreme climatic event. We used ground- and satellite-based black mangrove (Avicennia germinans) leaf damage data from the northern Gulf of Mexico (USA and Mexico) to examine the effects of an extreme freeze in a region where black mangroves are expanding their range. The February 2021 event produced coastal temperatures as low as − 10 °C in some areas, exceeding thresholds for A. germinans damage and mortality. We used Sentinel-2 surface reflectance data to assess vegetation greenness before and after the freeze, along with ground-based observations of A. germinans leaf damage. Our results show a negative, nonlinear threshold relationship between A. germinans leaf damage and minimum temperature, with a temperature threshold for leaf damage near − 6 °C. Satellite-based analyses indicate that, at the landscape scale, damage was particularly severe along the central Texas coast, where the freeze event affected \u3e 2000 ha of A. germinans-dominated coastal wetlands. Our analyses highlight the value of pairing remotely sensed data with regional, ground-based observations for quantifying and extrapolating the effects of extreme freeze events on mangroves and other tropical, cold-sensitive plants. The results also demonstrate how extreme freeze events govern the expansion and contraction of mangroves near northern range limits in North America

    Beyond just sea-level rise: considering macroclimatic drivers within coastal wetland vulnerability assessments to climate change

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    Due to their position at the land-sea interface, coastal wetlands are vulnerable to many aspects of climate change. However, climate change vulnerability assessments for coastal wetlands generally focus solely on sea-level rise without considering the effects of other facets of climate change. Across the globe and in all ecosystems, macroclimatic drivers (e.g., temperature and rainfall regimes) greatly influence ecosystem structure and function. Macroclimatic drivers have been the focus of climate change-related threat evaluations for terrestrial ecosystems, but largely ignored for coastal wetlands. In some coastal wetlands, changing macroclimatic conditions are expected to result in foundation plant species replacement, which would affect the supply of certain ecosystem goods and services and could affect ecosystem resilience. As examples, we highlight several ecological transition zones where small changes in macroclimatic conditions would result in comparatively large changes in coastal wetland ecosystem structure and function. Our intent in this communication is not to minimize the importance of sea-level rise. Rather, our overarching aim is to illustrate the need to also consider macroclimatic drivers within vulnerability assessments for coastal wetlands

    Universal HIV testing in London tuberculosis clinics: a cluster randomised controlled trial

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    We assessed whether implementation of a combination of interventions in London tuberculosis clinics raised the levels of HIV test offers, acceptance and coverage. A stepped-wedge cluster randomised controlled trial was conducted across 24 clinics. Interventions were training of clinical staff and provision of tailor-made information resources with or without a change in clinic policy from selective to universal HIV testing. The primary outcome was HIV test acceptance amongst those offered a test, before and after the intervention; the secondary outcome was an offer of HIV testing. Additionally, the number and proportion of HIV tests among all clinic attendees (coverage) was assessed. 1,315 patients were seen in 24 clinics. The offer and coverage of testing rose significantly in clinics without (p = 0.002 and p = 0.004, respectively) and with an existing policy of universal testing (p = 0.02 and p = 0.04, respectively). However, the level of HIV test acceptance did not increase in 18 clinics without routine universal testing (p = 0.76) or the six clinics with existing universal testing (p = 0.40). The intervention significantly increased the number of HIV tests offered and proportion of participants tested, although acceptance did not change significantly. However, the magnitude of increase is modest due to the high baseline coverage

    Retinoic acid-responsive CD8 effector T-cells are selectively increased in IL-23-rich tissue in gastrointestinal GvHD.

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    Gastrointestinal (GI) graft-versus-host disease (GvHD) is a major barrier in allogeneic hematopoietic stem-cell transplantation (AHST). The metabolite retinoic acid (RA) potentiates GI-GvHD in mice via alloreactive T-cells expressing the RA-receptor-alpha (RARα), but the role of RA-responsive cells in human GI-GvHD remains undefined. We therefore used conventional and novel sequential immunostaining and flow cytometry to scrutinize RA-responsive T-cells in tissues and blood of AHST patients and characterize the impact of RA on human T-cell alloresponses. Expression of RARα by human mononuclear cells was increased after RA exposure. RARαhi mononuclear cells were increased in GI-GvHD tissue, contained more cellular RA-binding proteins, localized with tissue damage and correlated with GvHD severity and mortality. Using a targeted candidate protein approach we predicted the phenotype of RA-responsive T-cells in the context of increased microenvironmental IL-23. Sequential immunostaining confirmed the presence of a population of RARahi CD8 T-cells with the predicted phenotype, co-expressing the effector T-cell transcription factor T-bet and the IL-23-specific receptor. These cells were increased in GI- but not skin-GvHD tissues and were also selectively expanded in GI-GvHD patient blood. Finally, functional approaches demonstrated RA predominantly increased alloreactive GI-tropic RARahi CD8 effector T-cells, including cells with the phenotype identified in vivo. IL-23-rich conditions potentiated this effect by selectively increasing b7 integrin expression on CD8 effector T-cells and reducing CD4 T-cells with a regulatory cell phenotype. In conclusion we have identified a population of RA-responsive effector T-cells with a distinctive phenotype which are selectively expanded in human GI-GvHD and represent a potential new therapeutic target

    Relationship between physiological measures of excitability and levels of glutamate and GABA in the human motor cortex

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    Magnetic resonance spectroscopy (MRS) allows measurement of neurotransmitter concentrations within a region of interest in the brain. Inter-individual variation in MRS-measured GABA levels have been related to variation in task performance in a number of regions. However, it is not clear how MRS-assessed measures of GABA relate to cortical excitability or GABAergic synaptic activity. We therefore performed two studies investigating the relationship between neurotransmitter levels as assessed by MRS and transcranial magnetic stimulation (TMS) measures of cortical excitability and GABA synaptic activity in the primary motor cortex. We present uncorrected correlations, where the P value should therefore be considered with caution. We demonstrated a correlation between cortical excitability, as assessed by the slope of the TMS input-output curve and MRS-assessed glutamate levels (r = 0.803, P = 0.015) but no clear relationship between MRS-assessed GABA levels and TMS-assessed synaptic GABA(A) activity (2.5 ms inter-stimulus interval (ISI) short-interval intracortical inhibition (SICI); Experiment 1: r = 0.33, P = 0.31; Experiment 2: r = -0.23, P = 0.46) or GABA(B) activity (long-interval intracortical inhibition (LICI); Experiment 1: r = -0.47, P = 0.51; Experiment 2: r = 0.23, P = 0.47). We demonstrated a significant correlation between MRS-assessed GABA levels and an inhibitory TMS protocol (1 ms ISI SICI) with distinct physiological underpinnings from the 2.5 ms ISI SICI (r = -0.79, P = 0.018). Interpretation of this finding is challenging as the mechanisms of 1 ms ISI SICI are not well understood, but we speculate that our results support the possibility that 1 ms ISI SICI reflects a distinct GABAergic inhibitory process, possibly that of extrasynaptic GABA tone

    Hepatitis B vaccination uptake in hard-to-reach populations in London: a cross-sectional study

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    BACKGROUND: In the UK, hepatitis B virus (HBV) incidence is associated with migrants from particular high-burden countries and population groups deemed 'hard-to-reach' by standard healthcare services: the homeless, people who inject drugs and ex-prisoners. Currently, there is a national targeted HBV vaccine policy for such at-risk groups, but there is limited recent evidence about 1) the levels of vaccine uptake, 2) the factors associated with incomplete vaccination, and 3) reasons for incomplete vaccination. METHODS: A questionnaire capturing social and medical history, demographic factors and information about HBV vaccination status was completed by individuals deemed hard-to-reach due to socio-structural factors that criminalise, isolate and stigmatise who consented to participate in a randomised controlled trial of a peer intervention to promote engagement with hepatitis C services. The questionnaire also captured the reasons for incomplete vaccination. Descriptive, univariable and multivariable regression analyses were undertaken. RESULTS: Three hundred fourty six participants completed the questionnaire. 1) 52.3% (n = 181) reported full HBV vaccination. 2) Within a multivariable model adjusting for sociodemographic variables, the presence of one or two or more socio-structural factors that are included in the national targeted vaccination policy was associated with protection against incomplete HBV vaccination (51.7% vaccine coverage in those with one factor, odds ratio 0.43 [95% confidence interval 0.20-0.92]); 70.1% coverage with two or more factors, 0.19 [0.09-0.39]; overall p-value < 0.001). Being female was also associated with lower vaccine uptake (2.37 [1.24-4.57], 0.01). Examining the socio-structural factors individually, intravenous drug use was associated with protection against incomplete HBV vaccination. 3) The most common reasons declared for incomplete vaccination were never being offered the vaccine or not returning for further doses. CONCLUSION: Within this study of HBV vaccination uptake among hard-to-reach population groups in London, UK, we document 52.3% coverage of the full vaccine course. Critically, although participants recommended for immunisation within national guidelines had an increased likelihood of receiving a complete vaccine course, we note surprisingly low coverage in the presence of the risk factors that are national indicators for vaccination. Public health bodies should make additional efforts to improve coverage in the hard-to-reach through improved vaccine delivery systems. TRIAL REGISTRATION: ISRCTN24707359 , Registered 19th October 2012
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