1,766 research outputs found
Correlations of near-infrared, optical and X-ray luminosity for early-type galaxies
The relation between X-ray luminosity and near-infrared luminosity for
early-type galaxies has been examined. Near-infrared (NIR) luminosities should
provide a superior measure of stellar mass compared to optical luminosities
used in previous studies, especially if there is significant star-formation or
dust present in the galaxies. However, we show that the X-ray-NIR relations are
remarkably consistent with the X-ray-optical relations. This indicates that the
large scatter of the relations is dominated by scatter in the X-ray properties
of early-type galaxies, and is consistent with early-types consisting of old,
quiescent stellar populations.
We have investigated scatter in terms of environment, surface brightness
profile, Mg2, H_beta, H_gamma line strength indices, spectroscopic age, and
nuclear H_alpha emission. We found that galaxies with high Mg2 index, low
H_beta and H_gamma indices or a `core' profile have a large scatter in Lx,
whereas galaxies with low Mg2, high H_beta and H_gamma indices or `power-law'
profiles, generally have Lx<10^41 erg/s. There is no clear trend in the scatter
with environment or nuclear H_alpha emission.Comment: Accepted for publication in MNRAS. 22 pages, 15 figure
Gene-knockdown in the honey bee mite Varroa destructor by a non-invasive approach : studies on a glutathione S-transferase
Peer reviewedPublisher PD
Advancing spaceborne tools for the characterization of planetary ionospheres and circumstellar environments
This work explores remote sensing of planetary atmospheres and their circumstellar surroundings. The terrestrial ionosphere is a highly variable space plasma embedded in the thermosphere. Generated by solar radiation and predominantly composed of oxygen ions at high altitudes, the ionosphere is dynamically and chemically coupled to the neutral atmosphere. Variations in ionospheric plasma density impact radio astronomy and communications. Inverting observations of 83.4 nm photons resonantly scattered by singly ionized oxygen holds promise for remotely sensing the ionospheric plasma density. This hypothesis was tested by comparing 83.4 nm limb profiles recorded by the Remote Atmospheric and Ionospheric Detection System aboard the International Space Station to a forward model driven by coincident plasma densities measured independently via ground-based incoherent scatter radar. A comparison study of two separate radar overflights with different limb profile morphologies found agreement between the forward model and measured limb profiles. A new implementation of Chapman parameter retrieval via Markov chain Monte Carlo techniques quantifies the precision of the plasma densities inferred from 83.4 nm emission profiles. This first study demonstrates the utility of 83.4 nm emission for ionospheric remote sensing.
Future visible and ultraviolet spectroscopy will characterize the composition of exoplanet atmospheres; therefore, the second study advances technologies for the direct imaging and spectroscopy of exoplanets. Such spectroscopy requires the development of new technologies to separate relatively dim exoplanet light from parent star light. High-contrast observations at short wavelengths require spaceborne telescopes to circumvent atmospheric aberrations. The Planet Imaging Concept Testbed Using a Rocket Experiment (PICTURE) team designed a suborbital sounding rocket payload to demonstrate visible light high-contrast imaging with a visible nulling coronagraph. Laboratory operations of the PICTURE coronagraph achieved the high-contrast imaging sensitivity necessary to test for the predicted warm circumstellar belt around Epsilon Eridani. Interferometric wavefront measurements of calibration target Beta Orionis recorded during the second test flight in November 2015 demonstrate the first active wavefront sensing with a piezoelectric mirror stage and activation of a micromachine deformable mirror in space.
These two studies advance our ``close-to-home'' knowledge of atmospheres and move exoplanetary studies closer to detailed measurements of atmospheres outside our solar system
Transcriptome analysis of the synganglion from the honey bee mite, Varroa destructor and RNAi knockdown of neural peptide targets
Acknowledgements This work was funded by BBSRC-LINK grant # BB/J01009X/1 and Vita Europe Ltd. We are grateful to the Scottish Beekeepers Association, especially Mr Phil McAnespie in supporting this work at its inception. We acknowledge partial funding from a Genesis Faraday SPARK Award, part of a Scottish Government SEEKIT project for the early part of this work. We are grateful to Prof David Evans for his advice on Varroa destructor viruses.Peer reviewedPostprin
A real-time PCR method for quantification of the total and major variant strains of the Deformed wing virus
Funding: ELB was supported by a Biotechnology and Biological Sciences Research Council (BBSRC) EASTBIO Doctoral Training Partnership (http://www.bbsrc.ac.uk) [grant number BB/J01446X/1] and an Eastern Association Regional Studentship (EARS) and The Morley Agricultural Foundation awarded to ASB. CRC was supported by a KTN BBSRC CASE studentship (BB/M503526/1) (http://www.bbsrc.ac.uk), part-funded by the Scottish Beekeeping Association (https://www.scottishbeekeepers.org.uk/) and the Animal Health - Disease Prevention, Scottish Government awarded to ASB CRC. This project received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 613960 (SMARTBEES) (http://www.smartbees-fp7.eu/) awarded to ASB. The funders had no role in study design, data collection and analysis decision to publish, or preparation of the manuscript. Acknowledgments The authors wish to thank Mr W. Thrale, Mr Z. Blackmore, Mr J. Quinlan, and Mr J. Palombo for sample collection from the South East of England and Margie Ramsey for Beinn Eighe National Nature Reserve sample collection.Peer reviewedPublisher PD
Development of on-line FTIR spectroscopy for siloxane detection in biogas to enhance carbon contactor management
Activated carbon filters are used to limit engine damage by siloxanes when biogas is utilised to provide electricity. However, carbon filter siloxane removal performance is poorly understood as until recently, it had not been possible to measure siloxanes on-line. In this study, on-line Fourier Transform Infrared (FTIR) spectroscopy was developed to measure siloxane concentration in real biogas both upstream (86.1–157.5 mg m−3) and downstream (2.2–4.3 mg m−3) of activated carbon filters. The FTIR provided reasonable precision upstream of the carbon vessel with a root mean square error of 10% using partial least squares analysis. However, positive interference from volatile organic carbons was observed in downstream gas measurements limiting precision at the outlet to an RMSE of 1.5 mg m−3 (47.8%). Importantly, a limit of detection of 3.2 mg m−3 was identified which is below the recommended siloxane limit and evidences the applicability of on-line FTIR for this application
An Open-Source Gaussian Beamlet Decomposition Tool for Modeling Astronomical Telescopes
In the pursuit of directly imaging exoplanets, the high-contrast imaging
community has developed a multitude of tools to simulate the performance of
coronagraphs on segmented-aperture telescopes. As the scale of the telescope
increases and science cases move toward shorter wavelengths, the required
physical optics propagation to optimize high-contrast imaging instruments
becomes computationally prohibitive. Gaussian Beamlet Decomposition (GBD) is an
alternative method of physical optics propagation that decomposes an arbitrary
wavefront into paraxial rays. These rays can be propagated expeditiously using
ABCD matrices, and converted into their corresponding Gaussian beamlets to
accurately model physical optics phenomena without the need of diffraction
integrals. The GBD technique has seen recent development and implementation in
commercial software (e.g. FRED, CODE V, ASAP) but appears to lack an
open-source platform. We present a new GBD tool developed in Python to model
physical optics phenomena, with the goal of alleviating the computational
burden for modeling complex apertures, many-element systems, and introducing
the capacity to model misalignment errors. This study demonstrates the synergy
of the geometrical and physical regimes of optics utilized by the GBD
technique, and is motivated by the need for advancing open-source physical
optics propagators for segmented-aperture telescope coronagraph design and
analysis. This work illustrates GBD with Poisson's spot calculations and show
significant runtime advantage of GBD over Fresnel propagators for many-element
systems.Comment: 13 pages, 9 figures, submitted to SPIE Astronomical Telescopes &
Instrumentation 202
WFIRST Coronagraph Technology Requirements: Status Update and Systems Engineering Approach
The coronagraphic instrument (CGI) on the Wide-Field Infrared Survey
Telescope (WFIRST) will demonstrate technologies and methods for high-contrast
direct imaging and spectroscopy of exoplanet systems in reflected light,
including polarimetry of circumstellar disks. The WFIRST management and CGI
engineering and science investigation teams have developed requirements for the
instrument, motivated by the objectives and technology development needs of
potential future flagship exoplanet characterization missions such as the NASA
Habitable Exoplanet Imaging Mission (HabEx) and the Large UV/Optical/IR
Surveyor (LUVOIR). The requirements have been refined to support
recommendations from the WFIRST Independent External Technical/Management/Cost
Review (WIETR) that the WFIRST CGI be classified as a technology demonstration
instrument instead of a science instrument. This paper provides a description
of how the CGI requirements flow from the top of the overall WFIRST mission
structure through the Level 2 requirements, where the focus here is on
capturing the detailed context and rationales for the CGI Level 2 requirements.
The WFIRST requirements flow starts with the top Program Level Requirements
Appendix (PLRA), which contains both high-level mission objectives as well as
the CGI-specific baseline technical and data requirements (BTR and BDR,
respectively)... We also present the process and collaborative tools used in
the L2 requirements development and management, including the collection and
organization of science inputs, an open-source approach to managing the
requirements database, and automating documentation. The tools created for the
CGI L2 requirements have the potential to improve the design and planning of
other projects, streamlining requirement management and maintenance. [Abstract
Abbreviated]Comment: 16 pages, 4 figure
Reference gene selection and RNA preservation protocol in the cat flea, Ctenocephalides felis, for gene expression studies
This work was supported by a Knowledge Transfer Network BBSRC Industrial Case (#414 BB/L502467/1) studentship in association Zoetis Inc.Peer reviewedPostprin
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