64 research outputs found

    Chiral restoration effects on the shear viscosity of a pion gas

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    We investigate the shear viscosity of a pion gas in relativistic kinetic theory, using the Nambu-Jona-Lasinio model to construct the pion mass and the pi-pi interaction at finite temperature. Whereas at low temperatures the scattering properties and, hence, the viscosity are in agreement with lowest-order chiral perturbation theory, we find strong medium modifications in the crossover region. Here the system is strongly coupled and the scattering lengths diverge, similarly as for ultra-cold Fermi gases at a Feshbach resonance. As a consequence, the ratio eta/s is found to be strongly reduced as compared to calculations without medium-modified masses and scattering amplitudes. However, the quantitative results are very sensitive to the details of the applied approximations.Comment: 15 pages, 12 figures; v2: extended discussions of the dressed sigma propagator and the low-temperature limit, typos corrected, accepted versio

    Visual stress, its treatment with spectral filters, and its relationship to visually induced motion sickness

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    We review the concept of visual stress and its relation to neurological disease. Visual stress can occur from the observation of images with unnatural spatial structure and an excess of contrast energy at spatial frequencies to which the visual system is generally most sensitive. Visual stress can often be reduced using spectral filters, provided the colour is selected with precision to suit each individual. The use of such filters and their effects on reading speed are reviewed. The filters have been shown to benefit patients with a variety of neurological conditions other than reading difficulty, all associated with an increased risk of seizures. © 2009 Elsevier Ltd

    Is Area-Wide Pest Management Useful? The Case of Citrus Greening.

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    Citrus greening currently poses a severe threat to citrus production worldwide. No treatment or management strategy is yet available to cure the disease. Scientists recommend controlling the vector of the disease, and area-wide pest management has been proposed as a superior alternative to individual pest management. We analyzed a unique dataset of farm-level citrus yields that allowed us to test this hypothesis. We found that yields of blocks located in an area with higher participation in coordinated sprays were 28%, 73% and 98% percent higher in 2012/13, 2013/14, and 2014/15, respectively, compared to the yields of blocks under the same management but located in an area with lower participation; providing evidence on the efficiency of a well-performing pest management area to deal with HLB. However, participation in CHMAs has not been commensurate with this evidence. We present survey data that provide insights about producers’ preferences and attitudes toward the area-wide pest management program. Despite the economic benefit we found area-wide pest management can provide, the strategic uncertainty involved in relying on neighbors seems to impose too high of a cost for most growers, who end up not coordinating sprays

    The Concise Guide to PHARMACOLOGY 2023/24: Ion channels.

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    The Concise Guide to PHARMACOLOGY 2023/24 is the sixth in this series of biennial publications. The Concise Guide provides concise overviews, mostly in tabular format, of the key properties of approximately 1800 drug targets, and over 6000 interactions with about 3900 ligands. There is an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (https://www.guidetopharmacology.org/), which provides more detailed views of target and ligand properties. Although the Concise Guide constitutes almost 500 pages, the material presented is substantially reduced compared to information and links presented on the website. It provides a permanent, citable, point-in-time record that will survive database updates. The full contents of this section can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.16178. Ion channels are one of the six major pharmacological targets into which the Guide is divided, with the others being: G protein-coupled receptors, nuclear hormone receptors, catalytic receptors, enzymes and transporters. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. The landscape format of the Concise Guide is designed to facilitate comparison of related targets from material contemporary to mid-2023, and supersedes data presented in the 2021/22, 2019/20, 2017/18, 2015/16 and 2013/14 Concise Guides and previous Guides to Receptors and Channels. It is produced in close conjunction with the Nomenclature and Standards Committee of the International Union of Basic and Clinical Pharmacology (NC-IUPHAR), therefore, providing official IUPHAR classification and nomenclature for human drug targets, where appropriate

    Large-scale phenotyping of patients with long COVID post-hospitalization reveals mechanistic subtypes of disease

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    One in ten severe acute respiratory syndrome coronavirus 2 infections result in prolonged symptoms termed long coronavirus disease (COVID), yet disease phenotypes and mechanisms are poorly understood1. Here we profiled 368 plasma proteins in 657 participants ≥3 months following hospitalization. Of these, 426 had at least one long COVID symptom and 233 had fully recovered. Elevated markers of myeloid inflammation and complement activation were associated with long COVID. IL-1R2, MATN2 and COLEC12 were associated with cardiorespiratory symptoms, fatigue and anxiety/depression; MATN2, CSF3 and C1QA were elevated in gastrointestinal symptoms and C1QA was elevated in cognitive impairment. Additional markers of alterations in nerve tissue repair (SPON-1 and NFASC) were elevated in those with cognitive impairment and SCG3, suggestive of brain–gut axis disturbance, was elevated in gastrointestinal symptoms. Severe acute respiratory syndrome coronavirus 2-specific immunoglobulin G (IgG) was persistently elevated in some individuals with long COVID, but virus was not detected in sputum. Analysis of inflammatory markers in nasal fluids showed no association with symptoms. Our study aimed to understand inflammatory processes that underlie long COVID and was not designed for biomarker discovery. Our findings suggest that specific inflammatory pathways related to tissue damage are implicated in subtypes of long COVID, which might be targeted in future therapeutic trials

    Progress and Challenges in Coupled Hydrodynamic-Ecological Estuarine Modeling

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    Baseline geochemical mapping in the UK : the G-BASE programme

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    National geochemical mapping in the UK is undertaken by the BGS as part of the Geochemical Baseline Survey of the Environment (G-BASE) Programme. The programme began in the early 1970’s in the North of Scotland and will provide a comprehensive high resolution baseline geochemical database for the whole country by the year 2012. The ongoing development and inclusion of state-of-the-art analytical and computing techniques and rigorous quality control over the past 25 years have been fundamental in creating consistent geochemical maps which reflect geological, geomorphological and landuse parameters

    Modelling pesticide residues on greasy wool: Using organophosphate and synthetic pyrethroid survey data

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    Several surveys have examined the relationship between organophosphate and synthetic pyrethroid residues in wool and associated treatments. These have been combined and summarised using a model of on-farm survey data. The model estimated the amount of chemical taken up by the wool at application. This was based on experimental breakdown rates of these pesticides on wool determined in controlled trials. For about 10% of survey results the chemical measured on the wool did not match the chemical the producer said was applied. A further 5% of results were excluded because the amount of chemical detected on the wool was inconsistent with the stated time of treatment and shearing. With the remaining results there was a very high variation in residues resulting from the same (stated) treatment. It is clear that many producers do not know what chemicals they have used or how much they applied. The wide variation in results suggests that some producers may apply excessive amounts of pesticides while others use too little to have a useful effect. The model estimated the amount of pesticide taken up by the fleece using the residue left at shearing and the known breakdown rate for a given method and chemical group. When organophosphates were applied by dipping, the amount of chemical taken up by the fleece appeared to increase as the length of the wool increased. This was generally higher than would be anticipated from label dose rates but was consistent with the stripping characteristics of these chemicals. Therefore dipping as soon as possible after shearing left much lower residues (<10 mg/kg wool) than delayed treatment (often 10–30 mg/kg wool). In contrast the survey results suggest that the amount retained by sheep as a result of jetting decreased in longer wool. Jetting treatment rates appear to be lower than recommended, particularly for sheep with more than 6 months wool. Therefore jetting (as used by producers) left much lower residues in wool than dipping (with similar length wool) and was usually only above 10 mg/kg wool if carried out in the last 5 months before shearing, or if the same sheep received repeated treatments. The residue of synthetic pyrethroid retained in the fleece after dipping or long wool backliner application increased as the length of the wool increased at treatment, and appeared generally consistent with label recommendations. Current long wool backline products usually left residues of synthetic pyrethroid above 10 mg/kg on the wool. Short wool dipping left less than 10 mg/kg wool while off-shears backliners usually left average residue concentrations of about 2 mg/kg wool. Although the actual on-farm results vary 4-fold above and below the average, the model can be used to estimate the expected residue concentration and likely range of results from most standard on-farm organophosphate and synthetic pyrethroid treatments. This will allow improved provision of advice so that most producers can meet specified industry standards. It will allow wool buyers to estimate the risk of purchasing high residue wool based on producers’ statements about treatments applied
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