1,757 research outputs found
Densitometry and Thermometry of Starburst Galaxies
With a goal toward deriving the physical conditions in external galaxies, we
present a survey of formaldehyde (H2CO) and ammonia (NH3) emission and
absorption in a sample of starburst galaxies using the Green Bank Telescope. By
extending well-established techniques used to derive the spatial density in
star formation regions in our own Galaxy, we show how the relative intensity of
the 1(10)-1(11) and 2(11)-2(12) K-doublet transitions of H2CO can provide an
accurate densitometer for the active star formation environments found in
starburst galaxies (c.f. Mangum et al. 2008). Similarly, we employ the
well-established technique of using the relative intensities of the (1,1),
(2,2), and (4,4) transitions of NH3 to derive the kinetic temperature in
starburst galaxies. Our measurements of the kinetic temperature constrained
spatial density in our starburst galaxy sample represent the first mean density
measurements made toward starburst galaxies. We note a disparity between
kinetic temperature measurements derived assuming direct coupling to dust and
those derived from our NH3 measurements which points to the absolute need for
direct gas kinetic temperature measurements using an appropriate molecular
probe. Finally, our spatial density measurements point to a rough constancy to
the spatial density (10^{4.5} to 10^{5.5} cm^{-3}) in our starburst galaxy
sample. This implies that the Schmidt-Kennicutt relation between L_{IR} and
M_{dense}: (1) Is a measure of the dense gas mass reservoir available to form
stars, and (2) Is not directly dependent upon a higher average density driving
the star formation process in the most luminous starburst galaxies.Comment: 4 pages, to appear in proceedings of The 5th Zermatt ISM Symposiu
Negotiating equity in UK universities.
Description of the project The research involved six case studies of higher education institutions across England, Scotland and Wales. The project aims were:to explore staff experiences of equity issues and institutional equity policies. Participants were drawn from different occupational backgrounds and a variety of socio-cultural groups paying attention also to gender, sexual orientation, ‘race’/ethnicity, disability, age and religio to conduct a critical discourse analysis of equity policies in the six institution to gather the views of senior manager-academics and administrators on their institutional equality policies, and how these relate to national policie to identify challenges, inadequacies, examples of good practice, and constraints/incentives in relation to equity policies at institutional and sector level
Short-time homomorphic wavelet estimation
Successful wavelet estimation is an essential step for seismic methods like
impedance inversion, analysis of amplitude variations with offset and full
waveform inversion. Homomorphic deconvolution has long intrigued as a
potentially elegant solution to the wavelet estimation problem. Yet a
successful implementation has proven difficult. Associated disadvantages like
phase unwrapping and restrictions of sparsity in the reflectivity function
limit its application. We explore short-time homomorphic wavelet estimation as
a combination of the classical homomorphic analysis and log-spectral averaging.
The introduced method of log-spectral averaging using a short-term Fourier
transform increases the number of sample points, thus reducing estimation
variances. We apply the developed method on synthetic and real data examples
and demonstrate good performance.Comment: 13 pages, 5 figures. 2012 J. Geophys. Eng. 9 67
Opportunities for maser studies with the Square Kilometre Array
The Square Kilometre Array (SKA) is the radio telescope of the next
generation, providing an increase in sensitivity and angular resolution of two
orders of magnitude over existing telescopes. Currently, the SKA is expected to
span the frequency range 0.1-25 GHz with capabilities including a wide
field-of-view and measurement of polarised emission. Such a telescope has
enormous potential for testing fundamental physical laws and producing
transformational discoveries. Important science goals include using H2O
megamasers to make precise estimates of H0, which will anchor the extragalactic
distance scale, and to probe the central structures of accretion disks around
supermassive black holes in AGNs, to study OH megamasers associated with
extreme starburst activity in distant galaxies and to study with unprecedented
precision molecular gas and star formation in our Galaxy.Comment: 5 pages, to appear in: IAU Symposium 242 Astrophysical Masers and
their Environment
Stimulating teachers’ inquiring attitude in academic and professional teacher education programmes
A morphological algorithm for improving radio-frequency interference detection
A technique is described that is used to improve the detection of
radio-frequency interference in astronomical radio observatories. It is applied
on a two-dimensional interference mask after regular detection in the
time-frequency domain with existing techniques. The scale-invariant rank (SIR)
operator is defined, which is a one-dimensional mathematical morphology
technique that can be used to find adjacent intervals in the time or frequency
domain that are likely to be affected by RFI. The technique might also be
applicable in other areas in which morphological scale-invariant behaviour is
desired, such as source detection. A new algorithm is described, that is shown
to perform quite well, has linear time complexity and is fast enough to be
applied in modern high resolution observatories. It is used in the default
pipeline of the LOFAR observatory.Comment: Accepted for publication in A&
The involvement in inquiry-based working of teachers of research-intensive versus practically oriented teacher education programmes.
How can autonomy be maintained and informal care improved for people with dementia living in residential care facilities: A systematic literature review
Background and objectives: For people with dementia living in residential care facilities, maintaining autonomy and receiving informal care are important. The objective of this review is to understand how caregiving approaches and physical environment, including technologies contribute to the maintenance of autonomy and informal care provision for this population. Research design and method: A literature review of peer-reviewed articles published between January 1995 and July 2017 was performed. Realist logic of analysis was used, involving context, mechanism and outcome configurations. Results: Forty-nine articles were included. The improvement of the relationship between residents and formal/informal caregivers is important. This increases the knowledge (sharing) about the resident and contributes to their autonomy. A social, flexible, and welcoming attitude of the formal caregiver improves the provision of informal care. Specially designed spaces, for instance, therapeutic gardens, create activities for residents that remind them of themselves and contribute to their autonomy. Use of technologies reduces caregiver's time for primary tasks and therefore enables secondary tasks such as interaction with the residents. Discussion and implications: The results revealed how residential care facilities could maintain autonomy of their residents and improve informal care delivery using caregiving approaches and the physical environment including technologies. The results are supporting toward each other in maintaining autonomy and also helped in enhancing informal care provision. For residential care facilities that want to maintain the autonomy of their residents and improve informal care delivery, it is important to pay attention to all aspects of living in a residential care facility
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