1,851 research outputs found

    Genetic diversity, infection prevalence, and possible transmission routes of Bartonella spp. in vampire bats

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    Bartonella spp. are globally distributed bacteria that cause endocarditis in humans and domestic animals. Recent work has suggested bats as zoonotic reservoirs of some human Bartonella infections; however, the ecological and spatiotemporal patterns of infection in bats remain largely unknown. Here we studied the genetic diversity, prevalence of infection across seasons and years, individual risk factors, and possible transmission routes of Bartonella in populations of common vampire bats (Desmodus rotundus) in Peru and Belize, for which high infection prevalence has previously been reported. Phylogenetic analysis of the gltA gene for a subset of PCR-positive blood samples revealed sequences that were related to Bartonella described from vampire bats from Mexico, other Neotropical bat species, and streblid bat flies. Sequences associated with vampire bats clustered significantly by country but commonly spanned Central and South America, implying limited spatial structure. Stable and nonzero Bartonella prevalence between years supported endemic transmission in all sites. The odds of Bartonella infection for individual bats was unrelated to the intensity of bat flies ectoparasitism, but nearly all infected bats were infested, which precluded conclusive assessment of support for vector-borne transmission. While metagenomic sequencing found no strong evidence of Bartonella DNA in pooled bat saliva and fecal samples, we detected PCR positivity in individual saliva and feces, suggesting the potential for bacterial transmission through both direct contact (i.e., biting) and environmental (i.e., fecal) exposures. Further investigating the relative contributions of direct contact, environmental, and vector-borne transmission for bat Bartonella is an important next step to predict infection dynamics within bats and the risks of human and livestock exposures

    Virus taxonomy: the database of the International Committee on Taxonomy of Viruses (ICTV)

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    The International Committee on Taxonomy of Viruses (ICTV) is charged with the task of developing, refining, and maintaining a universal virus taxonomy. This task encompasses the classification of virus species and higher-level taxa according to the genetic and biological properties of their members; naming virus taxa; maintaining a database detailing the currently approved taxonomy; and providing the database, supporting proposals, and other virus-related information from an open-access, public web site. The ICTV web site (http://ictv.global) provides access to the current taxonomy database in online and downloadable formats, and maintains a complete history of virus taxa back to the first release in 1971. The ICTV has also published the ICTV Report on Virus Taxonomy starting in 1971. This Report provides a comprehensive description of all virus taxa covering virus structure, genome structure, biology and phylogenetics. The ninth ICTV report, published in 2012, is available as an open-access online publication from the ICTV web site. The current, 10th report (http://ictv.global/report/), is being published online, and is replacing the previous hard-copy edition with a completely open access, continuously updated publication. No other database or resource exists that provides such a comprehensive, fully annotated compendium of information on virus taxa and taxonomy

    Neptune at Summer Solstice: Zonal Mean Temperatures from Ground-Based Observations 2003-2007

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    Imaging and spectroscopy of Neptune's thermal infrared emission is used to assess seasonal changes in Neptune's zonal mean temperatures between Voyager-2 observations (1989, heliocentric longitude Ls=236) and southern summer solstice (2005, Ls=270). Our aim was to analyse imaging and spectroscopy from multiple different sources using a single self-consistent radiative-transfer model to assess the magnitude of seasonal variability. Globally-averaged stratospheric temperatures measured from methane emission tend towards a quasi-isothermal structure (158-164 K) above the 0.1-mbar level, and are found to be consistent with spacecraft observations of AKARI. This remarkable consistency, despite very different observing conditions, suggests that stratospheric temporal variability, if present, is ±\pm5 K at 1 mbar and ±\pm3 K at 0.1 mbar during this solstice period. Conversely, ethane emission is highly variable, with abundance determinations varying by more than a factor of two. The retrieved C2H6 abundances are extremely sensitive to the details of the T(p) derivation. Stratospheric temperatures and ethane are found to be latitudinally uniform away from the south pole (assuming a latitudinally-uniform distribution of stratospheric methane). At low and midlatitudes, comparisons of synthetic Voyager-era images with solstice-era observations suggest that tropospheric zonal temperatures are unchanged since the Voyager 2 encounter, with cool mid-latitudes and a warm equator and pole. A re-analysis of Voyager/IRIS 25-50 {\mu}m mapping of tropospheric temperatures and para-hydrogen disequilibrium suggests a symmetric meridional circulation with cold air rising at mid-latitudes (sub-equilibrium para-H2 conditions) and warm air sinking at the equator and poles (super-equilibrium para-H2 conditions). The most significant atmospheric changes are associated with the polar vortex (absent in 1989).Comment: 35 pages, 19 figures. Accepted for publication in Icaru

    Gender and Caste Intersectionality in India: An Analysis of the Nirbhaya Case, 16 December 2012

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    Purpose: This chapter deals with the concept of intersectionality with particular reference to the interconnectedness of gender, class and caste discrimination in India. Even though much of the work on intersectionality has been carried out by scholars from the United States with specific emphasis on gender and race, this framework can be applied universally to understand the multiple axes of power within a society that results in further marginalisation of certain groups of women. The 16th December 2012 Nirbhaya rape case forms the core of this chapter as it resulted in one of the biggest gender movements in India. Design/methodology/approach: In order to develop a critical analysis a case study approach was adopted and data collected by analysing online news reports, videos, articles on blogs and posts on social media outlets such as Facebook and Twitter. Findings: The findings of the research showed interesting intersections of gender and class with relation to this case, which has not been deeply analysed in order to understand the reasons behind the public uprising which resulted in the government action. Originality/value: It is important to look at gender violence in India through the lens of intersectionality since often it is the result of multiple levels of discrimination on the basis of class, caste, religion and geography. This is important to recognise in order to ensure that activism, education and changes in policy help to resolve problems related to extreme oppression and violence against women across the country

    Evaluation of modelling approaches for predicting the spatial distribution of soil organic carbon stocks at the national scale

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    Soil organic carbon (SOC) plays a major role in the global carbon budget. It can act as a source or a sink of atmospheric carbon, thereby possibly influencing the course of climate change. Improving the tools that model the spatial distributions of SOC stocks at national scales is a priority, both for monitoring changes in SOC and as an input for global carbon cycles studies. In this paper, we compare and evaluate two recent and promising modelling approaches. First, we considered several increasingly complex boosted regression trees (BRT), a convenient and efficient multiple regression model from the statistical learning field. Further, we considered a robust geostatistical approach coupled to the BRT models. Testing the different approaches was performed on the dataset from the French Soil Monitoring Network, with a consistent cross-validation procedure. We showed that when a limited number of predictors were included in the BRT model, the standalone BRT predictions were significantly improved by robust geostatistical modelling of the residuals. However, when data for several SOC drivers were included, the standalone BRT model predictions were not significantly improved by geostatistical modelling. Therefore, in this latter situation, the BRT predictions might be considered adequate without the need for geostatistical modelling, provided that i) care is exercised in model fitting and validating, and ii) the dataset does not allow for modelling of local spatial autocorrelations, as is the case for many national systematic sampling schemes

    Fundamental properties of the mammalian innate immune system revealed by multispecies comparison of type I interferon responses

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    The host innate immune response mediated by type I interferon (IFN) and the resulting up-regulation of hundreds of interferon-stimulated genes (ISGs) provide an immediate barrier to virus infection. Studies of the type I ‘interferome’ have mainly been carried out at a single species level, often lacking the power necessary to understand key evolutionary features of this pathway. Here, using a single experimental platform, we determined the properties of the interferomes of multiple vertebrate species and developed a webserver to mine the dataset. This approach revealed a conserved ‘core’ of 62 ISGs, including genes not previously associated with IFN, underscoring the ancestral functions associated with this antiviral host response. We show that gene expansion contributes to the evolution of the IFN system and that interferomes are shaped by lineage-specific pressures. Consequently, each mammal possesses a unique repertoire of ISGs, including genes common to all mammals and others unique to their specific species or phylogenetic lineages. An analysis of genes commonly down-regulated by IFN suggests that epigenetic regulation of transcription is a fundamental aspect of the IFN response. Our study provides a resource for the scientific community highlighting key paradigms of the type I IFN response

    Mid-Infrared Spectroscopy of Uranus from the Spitzer Infrared Spectrometer: 2. Determination of the Mean Composition of the Upper Troposphere and Stratosphere

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    Mid-infrared spectral observations Uranus acquired with the Infrared Spectrometer (IRS) on the Spitzer Space Telescope are used to determine the abundances of C2H2, C2H6, CH3C2H, C4H2, CO2, and tentatively CH3 on Uranus at the time of the 2007 equinox. For vertically uniform eddy diffusion coefficients in the range 2200-2600 cm2 s-1, photochemical models that reproduce the observed methane emission also predict C2H6 profiles that compare well with emission in the 11.6-12.5 micron wavelength region, where the nu9 band of C2H6 is prominent. Our nominal model with a uniform eddy diffusion coefficient Kzz = 2430 cm2 sec-1 and a CH4 tropopause mole fraction of 1.6x10-5 provides a good fit to other hydrocarbon emission features, such as those of C2H2 and C4H2, but the model profile for CH3C2H must be scaled by a factor of 0.43, suggesting that improvements are needed in the chemical reaction mechanism for C3Hx species. The nominal model is consistent with a CH3D/CH4 ratio of 3.0+-0.2x10-4. From the best-fit scaling of these photochemical-model profiles, we derive column abundances above the 10-mbar level of 4.5+01.1/-0.8 x 10+19 molecule-cm-2 for CH4, 6.2 +- 1.0 x 10+16 molecule-cm-2 for C2H2 (with a value 24% higher from a different longitudinal sampling), 3.1 +- 0.3 x 10+16 molecule-cm-2 for C2H6, 8.6 +- 2.6 x 10+13 molecule-cm-2 for CH3C2H, 1.8 +- 0.3 x 10+13 molecule-cm-2 for C4H2, and 1.7 +- 0.4 x 10+13 molecule-cm-2 for CO2 on Uranus. Our results have implications with respect to the influx rate of exogenic oxygen species and the production rate of stratospheric hazes on Uranus, as well as the C4H2 vapor pressure over C4H2 ice at low temperatures

    No evidence for distinct types in the evolution of SARS-CoV-2

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    A recent study by Tang et al. claimed that two major types of severe acute respiratory syndrome-coronavirus-2 (CoV-2) had evolved in the ongoing CoV disease-2019 pandemic and that one of these types was more ‘aggressive’ than the other. Given the repercussions of these claims and the intense media coverage of these types of articles, we have examined in detail the data presented by Tang et al., and show that the major conclusions of that paper cannot be substantiated. Using examples from other viral outbreaks, we discuss the difficulty in demonstrating the existence or nature of a functional effect of a viral mutation, and we advise against overinterpretation of genomic data during the pandemic
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