IL-17 can be protective or deleterious in murine pneumococcal pneumonia

Streptococcus pneumoniae is the major bacterial cause of community-acquired pneumonia, and the leading agent of childhood pneumonia deaths worldwide. Nasal colonization is an essential step prior to infection. The cytokine IL-17 protects against such colonization and vaccines that enhance IL-17 responses to pneumococcal colonization are being developed. The role of IL-17 in host defence against pneumonia is not known. To address this issue, we have utilized a murine model of pneumococcal pneumonia in which the gene for the IL-17 cytokine family receptor, Il17ra, has been inactivated. Using this model, we show that IL-17 produced predominantly from γδ T cells protects mice against death from the invasive TIGR4 strain (serotype 4) which expresses a relatively thin capsule. However, in pneumonia produced by two heavily encapsulated strains with low invasive potential (serotypes 3 and 6B), IL-17 significantly enhanced mortality. Neutrophil uptake and killing of the serotype 3 strain was significantly impaired compared to the serotype 4 strain and depletion of neutrophils with antibody enhanced survival of mice infected with the highly encapsulated SRL1 strain. These data strongly suggest that IL-17 mediated neutrophil recruitment to the lungs clears infection from the invasive TIGR4 strain but that lung neutrophils exacerbate disease caused by the highly encapsulated pneumococcal strains. Thus, whilst augmenting IL-17 immune responses against pneumococci may decrease nasal colonization, this may worsen outcome during pneumonia caused by some strains

Axisymmetric Three-Integral Models for Galaxies

We describe an improved, practical method for constructing galaxy models that match an arbitrary set of observational constraints, without prior assumptions about the phase-space distribution function (DF). Our method is an extension of Schwarzschild's orbit superposition technique. As in Schwarzschild's original implementation, we compute a representative library of orbits in a given potential. We then project each orbit onto the space of observables, consisting of position on the sky and line-of-sight velocity, while properly taking into account seeing convolution and pixel binning. We find the combination of orbits that produces a dynamical model that best fits the observed photometry and kinematics of the galaxy. A key new element of this work is the ability to predict and match to the data the full line-of-sight velocity profile shapes. A dark component (such as a black hole and/or a dark halo) can easily be included in the models. We have tested our method, by using it to reconstruct the properties of a two-integral model built with independent software. The test model is reproduced satisfactorily, either with the regular orbits, or with the two-integral components. This paper mainly deals with the technical aspects of the method, while applications to the galaxies M32 and NGC 4342 are described elsewhere (van der Marel et al., Cretton & van den Bosch). (abridged)Comment: minor changes, accepted for publication in the Astrophysical Journal Supplement

The VIRUS-P Exploration of Nearby Galaxies (VENGA): Survey Design and First Results

VENGA is a large-scale extragalactic IFU survey, which maps the bulges, bars and large parts of the outer disks of 32 nearby normal spiral galaxies. The targets are chosen to span a wide range in Hubble types, star formation activities, morphologies, and inclinations, at the same time of having vast available multi-wavelength coverage from the far-UV to the mid-IR, and available CO and 21cm mapping. The VENGA dataset will provide 2D maps of the SFR, stellar and gas kinematics, chemical abundances, ISM density and ionization states, dust extinction and stellar populations for these 32 galaxies. The uniqueness of the VIRUS-P large field of view permits these large-scale mappings to be performed. VENGA will allow us to correlate all these important quantities throughout the different environments present in galactic disks, allowing the conduction of a large number of studies in star formation, structure assembly, galactic feedback and ISM in galaxies.Comment: 7 pages, 3 figures, proceedings of the "Third Biennial Frank N. Bash Symposium, New Horizons in Astronomy" held in Austin, TX, Oct. 2009. To be published in the Astronomical Society of the Pacific Conference Series, eds. L. Stanford, L. Hao, Y. Mao, J. Gree

Modelling an energetic tidal strait:investigating implications of common numerical configuration choices

Representation of the marine environment is key for reliable coastal hydrodynamic models. This study investigates the implications of common depth-averaged model configuration choices in sufficiently characterising seabed geometry and roughness. In particular, applications requiring a high level of accuracy and/or exhibiting complex flow conditions may call for greater detail in marine environment representation than typically adopted in coastal models. Ramsey Sound, a macrotidal strait in Pembrokeshire, Wales, UK is considered as a case study. The site contains various steeply inclined bathymetric features, including a submerged pinnacle named Horse Rock and a rocky reef called “The Bitches”. The available energy in Ramsey Sound’s tidal currents has attracted attention from tidal energy developers. There is interest in accurately modelling the energetic hydrodynamics surrounding its pronounced bathymetry. The coastal flow solver Thetis is applied to simulate the flow conditions in Ramsey Sound. It is shown that notable prominent bathymetric features in the strait influence localised and, most importantly, regional hydrodynamic characteristics. “The Bitches” consistently accelerate flow in the strait while Horse Rock induces a notable wake structure and flow reversals. The model is calibrated against bed- and vessel-mounted Acoustic Doppler Current Profiler (ADCP) observations, by altering seabed roughness parameterisations. A spatially variable and locally scaled Manning coefficient based on diverse seabed classification observations is found to improve model performance in comparison to uniformly applied constants, the latter a more common approach. The local impact of altering the Manning coefficient configuration is found to be greatest during spring flood periods of high velocity currents. Meanwhile, the effect of coarsening the computational mesh around bathymetric features towards values more typically applied in coastal models is investigated. Results indicate severe misrepresentation of seabed geometry and subsequent wake hydrodynamics unless refined to a mesh element size that adequately represents Horse Rock and “The Bitches”

Outfoxing the fox: effect of prey odor on fox behavior in a pastoral landscape

Invasive mammalian predators have had a devastating effect on native species globally. The European red fox (Vulpes vulpes) is one such species where it has been introduced in Australia. A novel but unexplored tactic to reduce the impact of mammalian predators is the use of unrewarded prey odors to undermine the effectiveness of olfactory hunting behavior. To test the viability of unrewarded prey odors in an applied setting we investigated how foxes responded to the odors of three different prey species. We used the odors of two locally extinct native Australian marsupials; the eastern quoll (a smaller carnivore) and eastern bettong (a fungivore), and the European rabbit, an introduced herbivore. Conducting our research over a period of 3 weeks in a pastoral environment in South-eastern Australia, we used video observations of foxes' behaviors, as they encountered the different odors. We found a reduction in the number of fox visits to bettong odors in the third week. In contrast, we observed a sustained number of visits to rabbit odors. Foxes also spent more time investigating rabbit odors and displayed longer durations of vigilance behavior at quoll odors. Our results support the hypothesis that the exposure of wild foxes to unrewarded odors of novel prey species can reduce their interest in these odors, which might translate to a reduction in predation pressure. Our results also suggest, however, that olfactory pre-exposure may not be as effective at reducing fox interest in a competitor species' odor

On the gamma-ray emission from the core of the Sagittarius dwarf galaxy

We use data from the Large Area Telescope onboard the Fermi gamma-ray space telescope (Fermi-LAT) to analyze the faint gamma-ray source located at the center of the Sagittarius (Sgr) dwarf spheroidal galaxy. In the 4FGL-DR3 catalog, this source is associated with the globular cluster, M54, which is coincident with the dynamical center of this dwarf galaxy. We investigate the spectral energy distribution and spatial extension of this source, with the goal of testing two hypotheses: (1) the emission is due to millisecond pulsars within M54, or (2) the emission is due to annihilating dark matter from the Sgr halo. For the pulsar interpretation, we consider a two-component model which describes both the lower-energy magnetospheric emission and possible high-energy emission arising from inverse Compton scattering. We find that this source has a point-like morphology at low energies, consistent with magnetospheric emission, and find no evidence for a higher-energy component. For the dark matter interpretation, we find that this signal favors a dark matter mass of $m_{\chi} = 29.6 \pm 5.8$ GeV and an annihilation cross section of $\sigma v = (2.1 \pm 0.59) \times 10^{-26} \,\text{cm}^3/$s for the $b \bar{b}$ channel (or $m_{\chi} = 8.3 \pm 3.8$ GeV and $\sigma v = (0.90 \pm 0.25) \times 10^{-26} \, \text{cm}^3/$s for the $\tau^+ \tau^-$ channel), when adopting a J-factor of $J=10^{19.6} \, \text{GeV}^2 \, \text{cm}^{-5}$. This parameter space is consistent with gamma-ray constraints from other dwarf galaxies and with dark matter interpretations of the Galactic Center Gamma-Ray Excess.Comment: 12 pages, 9 figures. To be submitted to MNRAS -- comments welcom

Ten simple rules for writing Dockerfiles for reproducible data science.

Computational science has been greatly improved by the use of containers for packaging software and data dependencies. In a scholarly context, the main drivers for using these containers are transparency and support of reproducibility; in turn, a workflow's reproducibility can be greatly affected by the choices that are made with respect to building containers. In many cases, the build process for the container's image is created from instructions provided in a Dockerfile format. In support of this approach, we present a set of rules to help researchers write understandable Dockerfiles for typical data science workflows. By following the rules in this article, researchers can create containers suitable for sharing with fellow scientists, for including in scholarly communication such as education or scientific papers, and for effective and sustainable personal workflows