39 research outputs found
Local Cattle and Badger Populations Affect the Risk of Confirmed Tuberculosis in British Cattle Herds
Background: The control of bovine tuberculosis (bTB) remains a priority on the public health agenda in Great Britain, after launching in 1998 the Randomised Badger Culling Trial (RBCT) to evaluate the effectiveness of badger (Meles meles) culling as a control strategy. Our study complements previous analyses of the RBCT data (focusing on treatment effects) by presenting analyses of herd-level risks factors associated with the probability of a confirmed bTB breakdown in herds within each treatment: repeated widespread proactive culling, localized reactive culling and no culling (survey-only). Methodology/Principal Findings: New cases of bTB breakdowns were monitored inside the RBCT areas from the end of the first proactive badger cull to one year after the last proactive cull. The risk of a herd bTB breakdown was modeled using logistic regression and proportional hazard models adjusting for local farm-level risk factors. Inside survey-only and reactive areas, increased numbers of active badger setts and cattle herds within 1500 m of a farm were associated with an increased bTB risk. Inside proactive areas, the number of M. bovis positive badgers initially culled within 1500 m of a farm was the strongest predictor of the risk of a confirmed bTB breakdown. Conclusions/Significance: The use of herd-based models provide insights into how local cattle and badger populations affect the bTB breakdown risks of individual cattle herds in the absence of and in the presence of badger culling. These measures of local bTB risks could be integrated into a risk-based herd testing programme to improve the targeting o
First Data Release of the COSMOS Ly alpha Mapping and Tomography Observations: 3D Ly alpha Forest Tomography at 2.05 < z < 2.55
Faint star-forming galaxies at z ~ 2–3 can be used as alternative background sources to probe the Lyα forest in addition to quasars, yielding high sightline densities that enable 3D tomographic reconstruction of the foreground absorption field. Here, we present the first data release from the COSMOS Lyα Mapping And Tomography Observations (CLAMATO) Survey, which was conducted with the LRIS spectrograph on the Keck I telescope. Over an observational footprint of 0.157 deg2 within the COSMOS field, we used 240 galaxies and quasars at 2.17 < z < 3.00, with a mean comoving transverse separation of , as background sources probing the foreground Lyα forest absorption at 2.05 < z < 2.55. The Lyα forest data was then used to create a Wiener-filtered tomographic reconstruction over a comoving volume of with an effective smoothing scale of . In addition to traditional figures, this map is also presented as a virtual-reality visualization and manipulable interactive figure. We see large overdensities and underdensities that visually agree with the distribution of coeval galaxies from spectroscopic redshift surveys in the same field, including overdensities associated with several recently discovered galaxy protoclusters in the volume. Quantitatively, the map signal-to-noise is over a 3 h −1Mpc top-hat kernel based on the variances estimated from the Wiener filter. This data release includes the redshift catalog, reduced spectra, extracted Lyα forest pixel data, and reconstructed tomographic map of the absorption. These can be downloaded from Zenodo (10.5281/zenodo.1292459)
Thermal Transport in Micro- and Nanoscale Systems
Small-scale (micro-/nanoscale) heat transfer has broad and exciting range of applications. Heat transfer at small scale quite naturally is influenced – sometimes dramatically – with high surface area-to-volume ratios. This in effect means that heat transfer in small-scale devices and systems is influenced by surface treatment and surface morphology. Importantly, interfacial dynamic effects are at least non-negligible, and there is a strong potential to engineer the performance of such devices using the progress in micro- and nanomanufacturing technologies. With this motivation, the emphasis here is on heat conduction and convection. The chapter starts with a broad introduction to Boltzmann transport equation which captures the physics of small-scale heat transport, while also outlining the differences between small-scale transport and classical macroscale heat transport. Among applications, examples are thermoelectric and thermal interface materials where micro- and nanofabrication have led to impressive figure of merits and thermal management performance. Basic of phonon transport and its manipulation through nanostructuring materials are discussed in detail.
Small-scale single-phase convection and the crucial role it has played in developing the thermal management solutions for the next generation of electronics and energy-harvesting devices are discussed as the next topic. Features of microcooling platforms and physics of optimized thermal transport using microchannel manifold heat sinks are discussed in detail along with a discussion of how such systems also facilitate use of low-grade, waste heat from data centers and photovoltaic modules.
Phase change process and their control using surface micro-/nanostructure are discussed next. Among the feature considered, the first are microscale heat pipes where capillary effects play an important role. Next the role of nanostructures in controlling nucleation and mobility of the discrete phase in two-phase processes, such as boiling, condensation, and icing is explained in great detail. Special emphasis is placed on the limitations of current surface and device manufacture technologies while also outlining the potential ways to overcome them. Lastly, the chapter is concluded with a summary and perspective on future trends and, more importantly, the opportunities for new research and applications in this exciting field
The Staphylococcus aureus superantigen SElX is a bifunctional toxin that inhibits neutrophil function:SElX Inhibits Neutrophil Function
Bacterial superantigens (SAgs) cause Vβ-dependent T-cell proliferation leading to immune dysregulation associated with the pathogenesis of life-threatening infections such as toxic shock syndrome, and necrotizing pneumonia. Previously, we demonstrated that staphylococcal enterotoxin-like toxin X (SElX) from Staphylococcus aureus is a classical superantigen that exhibits T-cell activation in a Vβ-specific manner, and contributes to the pathogenesis of necrotizing pneumonia. Here, we discovered that SElX can also bind to neutrophils from human and other mammalian species and disrupt IgG-mediated phagocytosis. Site-directed mutagenesis of the conserved sialic acid-binding motif of SElX abolished neutrophil binding and phagocytic killing, and revealed multiple glycosylated neutrophil receptors for SElX binding. Furthermore, the neutrophil binding-deficient mutant of SElX retained its capacity for T-cell activation demonstrating that SElX exhibits mechanistically independent activities on distinct cell populations associated with acquired and innate immunity, respectively. Finally, we demonstrated that the neutrophil-binding activity rather than superantigenicity is responsible for the SElX-dependent virulence observed in a necrotizing pneumonia rabbit model of infection. Taken together, we report the first example of a SAg, that can manipulate both the innate and adaptive arms of the human immune system during S. aureus pathogenesis
A systematic compilation and classification of the literature on lameness in cattle.
This paper presents the first systematic review of the literature on lameness in cattle. It identifies, tabulates and classifies relevant published work and was conducted using electronic reference databases (BIDS ISI, BIOSIS, MEDLINE and the CAB Abstracts CD-ROM). A total of 1373 unique references were obtained from 1981 to 2000, of which 914 were written in the English language. A written search protocol was designed to ensure transparency and repeatability. Pilot studies were undertaken to create search terms that minimised bias and ensured relevance. Electronic files of the search terms allow the database to be updated in future. A further 93 references were included from the most recent international conference on lameness giving a total of 1007 English language references. The systematic review process is described, including a method of classifying papers according to their study design and statistical analysis, and it is hoped that other veterinary researchers will conduct similar reviews in their fields. The compiled and classified references are available as a searchable database through the web-sitehttp://cattle-lameness.dhs.org/. The review may be used in several ways; to identify practical interventions to reduce lameness in dairy cows and to use the resultant web-site as the basis of a decision support system for farmers, veterinarians and advisors
Obscured AGN at 1.5 < z < 3.0 from the zCOSMOS-deep Survey I. Properties of the emitting gas in the narrow-line region
The physics and demographics of high-redshift obscured active galactic nuclei (AGN) is still scarcely investigated. New
samples of such objects, selected with different techniques, can provide useful insights into their physical properties.
Aims. With the goal to determine the properties of the gas in the emitting region of type 2 AGN, in particular, the gas metal content,
we exploit predictions from photoionization models, including new parameterizations for the distance of gas distribution from the
central source and internal microturbulence in the emitting clouds, to interpret rest-frame UV spectral data.
Methods. We selected a sample of 90 obscured (type 2) AGN with 1.45 ≤ z ≤ 3.05 from the zCOSMOS-deep galaxy sample by 5σ
detection of the high-ionization C iv λ1549 narrow emission line. This feature in a galaxy spectrum is often associated with nuclear
activity, and the selection effectiveness has also been confirmed by diagnostic diagrams based on utraviolet (UV) emission-line ratios.
We applied the same selection technique and collected a sample of 102 unobscured (type 1) AGN. Taking advantage of the large
amount of multiband data available in the COSMOS field, we investigated the properties of the Civ-selected type 2 AGN, focusing on
their host galaxies, X-ray emission, and UV emission lines. Finally, we investigated the physical properties of the ionized gas in the
narrow-line region (NLR) of this type 2 AGN sample by combining the analysis of strong UV emission lines with predictions from
photoionization models.
Results. We find that in order to successfully reproduce the relative intensity of UV emission lines of the selected high-z type 2 AGN,
two new ingredients in the photoionization models are fundamental: small inner radii of the NLR (≈90 pc for LAGN = 1045 erg s−1
),
and the internal dissipative microturbulence of the gas-emitting clouds (with vmicr ≈ 100 km s−1
). With these modified models, we
compute the gas-phase metallicity of the NLR, and our measurements indicate a statistically significant evolution of the metal content
with redshift. Finally, we do not observe a strong relationship between the NLR gas metallicity and the stellar mass of the host galaxy
in our Civ-selected type 2 AGN sample.© ESO 2019We acknowledge financial support from the agreement
ASI-INAF n. 2017-14-H.O. A.F. acknowledges support from the ERC via an
Advanced Grant under grant agreement no. 321323-NEOGAL and no. 339659-
MUSICOS. A.C. acknowledges the support from the grants PRIN-MIUR 2015
and ASI n.I/023/12/0 and ASI n.2018-23-HH.0. Y.P. acknowledges National
Key R&D Program of China Grant 2016YFA0400702, and NSFC Grant
No. 11773001 and 11721303