3,642 research outputs found
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Sea ice and the ocean mixed layer over the Antarctic shelf seas
An ocean mixed-layer model has been incorporated into the Los Alamos sea ice
model CICE to investigate regional variations in the surface-driven formation
of Antarctic shelf waters. This model captures well the expected sea ice
thickness distribution, and produces deep (> 500 m) mixed layers in the
Weddell and Ross shelf seas each winter. This results in the complete
destratification of the water column in deep southern coastal regions leading
to high-salinity shelf water (HSSW) formation, and also in some shallower
regions (no HSSW formation) of these seas. Shallower mixed layers are
produced in the Amundsen and Bellingshausen seas. By deconstructing the
surface processes driving the mixed-layer depth evolution, we show that the
net salt flux from sea ice growth/melt dominates the evolution of the mixed
layer in all regions, with a smaller contribution from the surface heat flux
and a negligible input from wind stress. The Weddell and Ross shelf seas
receive an annual surplus of mixing energy at the surface; the Amundsen shelf
sea energy input in autumn/winter is balanced by energy extraction in
spring/summer; and the Bellingshausen shelf sea experiences an annual surface
energy deficit, through both a low energy input in autumn/winter and the
highest energy loss in spring/summer. An analysis of the sea ice mass balance
demonstrates the contrasting mean ice growth, melt and export in each region.
The Weddell and Ross shelf seas have the highest annual ice growth, with a
large fraction exported northwards each year, whereas the Bellingshausen
shelf sea experiences the highest annual ice melt, driven by the advection of
ice from the northeast. A linear regression analysis is performed to
determine the link between the autumn/winter mixed-layer deepening and
several atmospheric variables. The Weddell and Ross shelf seas show stronger
spatial correlations (temporal mean ā intra-regional variability) between the
autumn/winter mixed-layer deepening and several atmospheric variables
compared to the Amundsen and Bellingshausen. In contrast, the Amundsen and
Bellingshausen shelf seas show stronger temporal correlations (shelf sea mean
ā interannual variability) between the autumn/winter mixed-layer deepening
and several atmospheric variables
Morphological Classification of Local Luminous Infrared Galaxies
We present an analysis of the morphological classification of 89 luminous
infrared galaxies (LIRGs) from the Great Observatories All-sky LIRG Survey
(GOALS) sample using non-parametric coefficients and compare their morphology
as a function of wavelength. We rely on images obtained in the optical (B- and
I-band) as well as in the infrared (H-band and 5.8m). Our classification
is based on the calculation of and the second order of light ()
non-parametric coefficients which we explore as a function of stellar mass
(), infrared luminosity () and star formation rate (SFR). We
investigate the relation between , the specific SFR (sSFR) and the dust
temperature () in our galaxy sample. We find that is a
better morphological tracer than , as it allows to distinguish systems
formed by double systems from isolated and post-merger LIRGs. The
multi-wavelength analysis allows us to identify a region in the -
parameter space where ongoing mergers reside, regardless of the band used to
calculate the coefficients. In particular when measured in the H-band, this
region can be used to identify ongoing mergers, with a minimal contamination
from LIRGs in other stages. We also find that while the sSFR is positively
correlated with when measured in the mid-infrared, i.e. star-bursting
galaxies show more compact emission, it is anti-correlated with the B-band
based . We interpret this as the spatial decoupling between obscured
and un-obscured star formation, whereby the ultraviolet/optical size of a LIRGs
experience an intense dust enshrouded central starburst is larger than in the
one in the mid-infrared since the contrast between the nuclear to the extended
disk emission is smaller in the mid-infrared. This has important implications
for high redshift surveys of dusty sources. [abridged]Comment: ( 18 pages, 12 figures, Accepted for publication in A&A
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Sea iceāocean feedbacks in the Antarctic shelf seas
Observed changes in Antarctic sea ice are poorly understood, in part due to the complexity of its interactions with the atmosphere and ocean. A highly simplified, coupled sea iceāocean mixed layer model has been developed to investigate the importance of sea iceāocean feedbacks on the evolution of sea ice and the ocean mixed layer in two contrasting regions of the Antarctic continental shelf ocean: the Amundsen Sea, which has warm shelf waters, and the Weddell Sea, which has cold and saline shelf waters. Modeling studies where we deny the feedback response to surface air temperature perturbations show the importance of feedbacks on the mixed layer and ice cover in the Weddell Sea to be smaller than the sensitivity to surface atmospheric conditions. In the Amundsen Sea the effect of surface air temperature perturbations on the sea ice are opposed by changes in the entrainment of warm deep waters into the mixed layer. The net impact depends on the relative balance between changes in sea ice growth driven by surface perturbations and basal-driven melting. The changes in the entrainment of warm water in the Amundsen Sea were found to have a much larger impact on the ice volume than perturbations in the surface energy budget. This creates a net negative ice albedo feedback in the Amundsen Sea, reversing the sign of this typically positive feedback mechanism
Exploring the knowledge of communityābased nurses in supporting parents of preterm babies at home: A surveyābased study
AimThis study aimed to investigate the confidence levels, knowledge base and learning needs of community-based nurses relating to the care of preterm babies and parents, to explore what education is required and in what format.DesignAn online survey methodology was used.MethodsA 32-item questionnaire was distributed via social media platforms to community-based nurses in Australia.ResultsDescriptive analysis was undertaken relating to knowledge base, confidence levels, previous training, learning and resource needs and barriers to education. It was deemed vital to expand confidence and knowledge in this area. Gaps in learning resources were identified and a need for more training in topics such as developmental outcomes, feeding, expected milestones, weight gain, growth trajectories and supporting parents. Online resources were the preferred format to teach key knowledge to community-based health professionals, tailored to the specific features of preterm babies and support needs of parents
Optical Spectroscopic Survey of High-latitude WISE-selected Sources
We report on the results of an optical spectroscopic survey at high Galactic latitude (|b| ā„ 30Ā°) of a sample of WISE-selected targets, grouped by WISE W1 (Ī»_eff = 3.4 Ī¼m) flux, which we use to characterize the sources WISE detected. We observed 762 targets in 10 disjoint fields centered on ultraluminous infrared galaxy candidates using DEIMOS on Keck II. We find 0.30 Ā± 0.02 galaxies arcminā2 with a median redshift of z = 0.33 Ā± 0.01 for the sample with W1 ā„ 120 Ī¼Jy. The foreground stellar densities in our survey range from 0.23 Ā± 0.07 arcminā2 to 1.1 Ā± 0.1 arcminā2 for the same sample. We obtained spectra that produced science grade redshifts for ā„90% of our targets for sources with W1 flux ā„120 Ī¼Jy that also had an i-band flux gsim 18 Ī¼Jy. We used this for targeting very preliminary data reductions available to the team in 2010 August. Our results therefore present a conservative estimate of what is possible to achieve using WISE's Preliminary Data Release for the study of field galaxies
The knowledge and learning needs of health professionals in providing support for parents of premature babies at home: A mixed-methods study
Ā© 2019 The Authors Premature babies and their families often require on-going community-based care after discharge from the neonatal unit. Parents themselves have identified the need for health professionals to understand the specific needs of parents of premature babies in order to provide the optimal support they require. This study aimed to explore the existing knowledge base and learning needs of community health professionals, to further understand how they can adequately support parents in the community with premature babies. A mixed-methods approach was used comprising a questionnaire, semi-structured interviews and secondary data analysis. Participants included thirteen Health Visitor [HV] students, eight educators and seven parents from a previous study. Thematic analysis revealed important insights into the knowledge and learning needs necessary to support parents of premature babies in the community. Three main themes emerged: development of prior knowledge; the importance of practice-based learning; learning and training needs. Knowledge, confidence and skills in relation to caring for parents with premature babies varied between individuals depending on their placement during training and subsequent experiences. While transferable skills in supporting parents in the community were present, more education and training in the specific needs of premature babies and parents would be welcomed. Tailored resources for community-based health professionals on the specific needs of the premature baby would enhance provision of optimal support for parents
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On Visible Homelessness and the Micro-Aesthetics of Public Space
In this article, we investigate the circumstances that have produced the current municipal regulatory approach to homelessness in the City of Melbourne, Victoria, and the ways in which visibly homeless people are policed through a micro-aesthetics of their presence in public space, which involves the monitoring of their bodily demeanour and their physical possessions. Our study contributes to and draws from a range of debates, including studies of the governmental conjunction of poverty and crime, analysis of the co-implication of law and spatiality, research on the criminalisation of homelessness and homeless people, and the burgeoning criminological interest in the significance of the visual field for our understandings of crime and criminality. This article recounts how homelessness, public space and questions of aesthetics have recently coalesced in debates about the regulation of homelessness in the public space of Melbourneās city centre. It approaches the issues through comparative consideration of genres of municipal management frameworks in other jurisdictions, detailed textual consideration of the Protocol on Homelessness in the City of Melbourne and an empirical study of visible homelessness in the public places of central Melbourne
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