149 research outputs found

    Immune interactions and heterogeneity in transmission drives the pathogen-mediated invasion of grey squirrels in the UK

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    Mathematical models highlighted the importance of pathogen-mediated invasion, with the replacement of red squirrels by squirrelpox virus (SQPV) carrying grey squirrels in the UK, a well-known example. In this study, we combine new epidemiological models, with a range of infection characteristics, with recent longitudinal field and experimental studies on the SQPV dynamics in red and grey squirrel populations to better infer the mechanistic basis of the disease interaction. A key finding is that a model with either partial immunity or waning immunity and reinfection, where individuals become seropositive on the second exposure to infection, that up to now has been shown in experimental data only, can capture the key aspects of the field study observations. By fitting to SQPV epidemic observations in isolated red squirrel populations, we can infer that SQPV transmission between red squirrels is significantly (4×) higher than the transmission between grey squirrels and as a result our model shows that disease-mediated replacement of red squirrels by greys is considerably more rapid than replacement in the absence of SQPV. Our findings recover the key results of the previous model studies, which highlights the value of simple strategic models that are appropriate when there are limited data, but also emphasise the likely complexity of immune interactions in wildlife disease and how models can help infer disease processes from field data.</p

    Seguimiento de poblaciones con baja densidad: una perspectiva de qué nivel de declive poblacional podemos detectar con certeza

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    Monitoring of mammal species is an important part in detecting changes in their status. Efforts are based on a variety of direct and indirect methods and many low density populations are monitored through field signs. We present data on the endangered European red squirrel from Kidland Forest in the UK. We used cone transects to both record changes in seed availability and to monitor population trends. We examined the difficulty of accurately detecting population change when populations are low and field signs are patchily distributed. Current efforts would be sufficient to detect significant population declines of 50–75% in years with a modest squirrel population but not when they fall below one squirrel for every 20 ha of forest. The findings emphasise that monitoring aims have to be clearly defined with an awareness and understanding of what level of change the adopted methodological approach can reliably detect. We propose that mammal monitoring schemes need to be based on a pilot scheme to determine effect size and planned accordingly. Key words: Squirrel, Sciurus vulgaris, Conservation, Power analysis.El seguimiento de las especies de mamíferos es una parte importante de la detección de los cambios producidos en su estatus. Los esfuerzos van dirigidos hacia diversos métodos directos e indirectos, y muchas poblaciones que presentan una densidad baja se monitorizan mediante rastros o signos de campo. En este trabajo presentamos datos de una especie en peligro, la ardilla roja, del bosque de Kidland en el Reino Unido. Se realizaron transectos de detección de piñas o conos para registrar tanto los cambios en la disponibilidad de semillas como para monitorizar las tendencias de la población. Examinamos la dificultad que presenta detectar con precisión los cambios poblacionales, cuando las poblaciones son pequeñas y los restos alimentarios de presencia están distribuidos de forma desigual. Los esfuerzos normales deberían ser suficientes para detectar disminuciones poblacionales significativas del 50–75% en años con una población de ardillas modesta, pero no cuando la densidad está por debajo de una ardilla cada 20 ha de bosque. Nuestros hallazgos enfatizan que los esfuerzos de seguimiento deben estar claramente definidos, con el conocimiento y la comprensión de qué nivel de cambio puede realmente detectar de forma fiable el enfoque metodológico adoptado. Proponemos que los seguimientos de mamíferos deben estar basados en un esquema piloto, con el fin de determinar el efecto del tamaño, y ser planificados consecuentemente. Palabras clave: Ardilla, Sciurus vulgaris, Conservación, Análisis de potencia

    Spongiibacter marinus gen. nov., sp. nov., a halophilic marine bacterium isolated from the boreal sponge Haliclona sp. 1

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    Strain HAL40bT was isolated from the marine sponge Haliclona sp. 1 collected at the Sula Ridge off the Norwegian coast and characterized by physiological, biochemical and phylogenetic analyses. The isolate was a small rod with a polar flagellum. It was aerobic, Gram-negative and oxidase- and catalase-positive. Optimal growth was observed at 20–30 °C, pH 7–9 and in 3 % NaCl. Substrate utilization tests were positive for arabinose, Tween 40 and Tween 80. Enzyme tests were positive for alkaline phosphatase, esterase lipase (C8), leucine arylamidase, acid phosphatase, naphthol-AS-BI-phosphohydrolase and N-acetyl-β-glucosaminidase. The predominant cellular fatty acid was C17 : 1 ω8, followed by C17 : 0 and C18 : 1 ω7. Analysis by matrix-assisted laser desorption/ionization time-of-flight MS was used to characterize the strain, producing a characteristic low-molecular-mass protein pattern that could be used as a fingerprint for identification of members of this species. The DNA G+C content was 69.1 mol%. Phylogenetic analysis supported by 16S rRNA gene sequence comparison classified the strain as a member of the class Gammaproteobacteria. Strain HAL40bT was only distantly related to other marine bacteria including Neptunomonas naphthovorans and Marinobacter daepoensis (type strain sequence similarity >90 %). Based on its phenotypic, physiological and phylogenetic characteristics, it is proposed that the strain should be placed into a new genus as a representative of a novel species, Spongiibacter marinus gen. nov., sp. nov.; the type strain of Spongiibacter marinus is HAL40bT (=DSM 17750T =CCUG 54896T)

    Paediatric reference values for total psoas muscle area

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    Background: Sarcopenia, the unintentional loss of skeletal muscle mass, is associated with poor outcomes in adult patient populations. In adults, sarcopenia is often ascertained by cross-sectional imaging of the psoas muscle area (PMA). Although children with chronic medical illnesses may be at increased risk for muscle loss because of nutritional deficiencies, physical deconditioning, endocrine anomalies, and systemic inflammation, consistent quantitative definitions for sarcopenia in children are lacking. We aimed to generate paediatric reference values for PMA at two intervertebral lumbar levels, L3–4 and L4–5. Methods: In this cross-sectional study, we analysed abdominal computed tomography scans of consecutive children presenting to the emergency department. Participants were children 1–16 years who required abdominal cross-sectional imaging after paediatric trauma between January 1, 2005 and December 31, 2015 in a large Canadian quaternary care centre. Children with a documented chronic medical illness or an acute spinal trauma at presentation were excluded. Total PMA (tPMA) at levels L3–4 and L4–5 were measured in square millimetres (mm2) as the sum of left and right PMA. Age-specific and sex-specific tPMA percentile curves were modelled using quantile regression. Results: Computed tomography images from 779 children were included. Values of tPMA at L4–5 were significantly larger than at L3–4 at all ages, but their correlation was high for both girls (r = 0.95) and boys (r = 0.98). Amongst girls, tPMA 50th percentile values ranged from 365 to 2336 mm2 at L3–4 and from 447 to 2704 mm2 for L4–5. Amongst boys, 50th percentile values for tPMA ranged between 394 and 3050 mm2 at L3–4 and from 498 to 3513 mm2 at L4–5. Intraclass correlation coefficients were excellent at L3–4 (0.97, 95% CI 0.94 to 0.981) and L4–5 (0.99, 95% CI 0.986 to 0.995). Weight and tPMA were correlated, stratified by sex for boys (L3–4 r = 0.90; L4–5 r = 0.90) and for girls (L3–4 r = 0.87; L4–5 r = 0.87). An online application was subsequently developed to easily calculate age-specific and sex-specific z-scores and percentiles. Conclusions: We provide novel paediatric age-specific and sex-specific growth curves for tPMA at intervertebral L3–4 and L4–5 levels for children between the ages of 1-16 years. Together with an online tool (https://ahrc-apps.shinyapps.io/sarcopenia/), these tPMA curves should serve as a reference enabling earlier identification and targeted intervention of sarcopenia in children with chronic medical conditions

    Conservation of genetic uniqueness in remaining populations of red squirrels (Sciurus vulgaris L.) in the South of England

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    The Eurasian red squirrel (Sciurus vulgaris) is an emblematic species for conservation, and its decline in the British Isles exemplifies the impact that alien introductions can have on native ecosystems. Indeed, red squirrels in this region have declined dramatically over the last 60 years due to the spread of squirrelpox virus following the introduction of the gray squirrel (Sciurus carolinensis). Currently, red squirrel populations in Britain are fragmented and need to be closely monitored in order to assess their viability and the effectiveness of conservation efforts. The situation is even more dramatic in the South of England, where S. vulgaris survives only on islands (Brownsea Island, Furzey Island, and the Isle of Wight). Using the D‐loop, we investigated the genetic diversity and putative ancestry of the squirrels from Southern England and compared them to a European dataset composed of 1,016 samples from 54 populations. We found that our three populations were more closely related to other squirrels from the British Isles than squirrels from Europe, showed low genetic diversity, and also harbored several private haplotypes. Our study demonstrates how genetically unique the Southern English populations are in comparison with squirrels from the continental European range. We report the presence of four private haplotypes, suggesting that these populations may potentially harbor distinct genetic lineages. Our results emphasize the importance of preserving these isolated red squirrel populations for the conservation of the species

    Search For Exotic Tau-decays

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    The Crystal Ball detector at the Doris II storage ring at DESY was used to search for the exotic decay processes tau -&gt; e gamma, tau -&gt; e pi0, tau -&gt; e eta. No signal was observed. We obtained the following 90% CL upper limits on the branching fractions:B(tau -&gt; e gamma)&lt; 2.0x10^(-4),B(tau -&gt; e pi0) &lt; 1.4x10^(-4),B(tau -&gt; e eta) &lt; 2.4x10^(-4)

    Why the Question of Animal Consciousness Might Not Matter Very Much

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    According to higher-order thought accounts of phenomenal consciousness (e.g. Carruthers, 2000) it is unlikely that many non-human animals undergo phenomenally conscious experiences. Many people believe that this result would have deep and far-reaching consequences. More specifically, they believe that the absence of phenomenal consciousness from the rest of the animal kingdom must mark a radical and theoretically significant divide between ourselves and other animals, with important implications for comparative psychology. I shall argue that this belief is mistaken. Since phenomenal consciousness might be almost epiphenomenal in its functioning within human cognition, its absence in animals may signify only relatively trivial differences in cognitive architecture. Our temptation to think otherwise arises partly as a side-effect of imaginative identification with animal experiences, and partly from mistaken beliefs concerning the aspects of common-sense psychology that carry the main explanatory burden, whether applied to humans or to non-human animals

    Heart valve disease: investigation by cardiovascular magnetic resonance

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    Cardiovascular magnetic resonance (CMR) has become a valuable investigative tool in many areas of cardiac medicine. Its value in heart valve disease is less well appreciated however, particularly as echocardiography is a powerful and widely available technique in valve disease. This review highlights the added value that CMR can bring in valve disease, complementing echocardiography in many areas, but it has also become the first-line investigation in some, such as pulmonary valve disease and assessing the right ventricle. CMR has many advantages, including the ability to image in any plane, which allows full visualisation of valves and their inflow/outflow tracts, direct measurement of valve area (particularly for stenotic valves), and characterisation of the associated great vessel anatomy (e.g. the aortic root and arch in aortic valve disease). A particular strength is the ability to quantify flow, which allows accurate measurement of regurgitation, cardiac shunt volumes/ratios and differential flow volumes (e.g. left and right pulmonary arteries). Quantification of ventricular volumes and mass is vital for determining the impact of valve disease on the heart, and CMR is the 'Gold standard' for this. Limitations of the technique include partial volume effects due to image slice thickness, and a low ability to identify small, highly mobile objects (such as vegetations) due to the need to acquire images over several cardiac cycles. The review examines the advantages and disadvantages of each imaging aspect in detail, and considers how CMR can be used optimally for each valve lesion
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