871 research outputs found
Vitamin D in Australia : issues and recommendations
BACKGROUND A significant number of Australians and people from specific groups within the community are suffering from vitamin D deficiency. It is no longer acceptable to assume that all people in Australia receive adequate vitamin D from casual exposure to sunlight.OBJECTIVE This article provides information on causes, consequences, treatment and prevention of vitamin D deficiency in Australia. DISCUSSION People at high risk of vitamin D deficiency include the elderly, those with skin conditions where avoidance of sunlight is required, dark skinned people (particularly women during pregnancy or if veiled) and patients with malabsorption, eg. coeliac disease. For most people, deficiency can be prevented by 5–15 minutes exposure of face and upper limbs to sunlight 4–6 times per week. If this is not possible then a vitamin D supplement of at least 400 IU* per day is recommended. In cases of established vitamin D deficiency, supplementation with 3000-5000 IU per day for at least 1 month is required to replete body stores. Increased availability of larger dose preparations of cholecalciferol would be a useful therapy in the case of severe deficiencies. * 40 IU (international units) = 1 µg<br /
Resolution of the Compact Radio Continuum Sources in Arp220
We present 2 cm and 3.6 cm wavelength very long baseline interferometry
images of the compact radio continuum sources in the nearby ultra-luminous
infrared galaxy Arp220. Based on their radio spectra and variability
properties, we confirm these sources to be a mixture of supernovae (SNe) and
supernova remnants (SNRs). Of the 17 detected sources we resolve 7 at both
wavelengths. The SNe generally only have upper size limits. In contrast all the
SNRs are resolved with diameters {\geq} 0.27 pc. This size limit is consistent
with them having just entered their Sedov phase while embedded in an
interstellar medium (ISM) of density 10^4 cm^{-3} . These objects lie on the
diameter-luminosity correlation for SNRs (and so also on the diameter-surface
brightness relation) and extend these correlations to very small sources. The
data are consistent with the relation L {\propto} D^{-9/4}. Revised
equipartition arguments adjusted to a magnetic field to relativistic particle
energy density ratio of 1% combined with a reasonable synchrotron-emitting
volume filling factor of 10% give estimated magnetic field strengths in the SNR
shells of ~ 15-50 mG. The SNR shell magnetic fields are unlikely to come from
compression of ambient ISM fields and must instead be internally generated. We
set an upper limit of 7 mG for the ISM magnetic field. The estimated energy in
relativistic particles, 2%-20% of the explosion kinetic energy, is consistent
with estimates from models that fit the IR-radio correlation in compact
starburst galaxies.Comment: 16 pages, 5 figure
Multiwavelength radio observations of the compact starburst in Arp 220
We report the first detection at multiple radio wavelengths (13, 6, and 3.6 cm) of 18 compact
sources within both nuclei of the Ultra Luminous Infra-Red Galaxy (ULIRG) Arp 220. In just
over half of the sources we find that the observed spectra are consistent with the standard model
of powerful Type IIn supernovae interacting with their pre-explosion stellar wind. The rate of appearance
of new radio sources ascribed to these supernova events suggests that a large fraction of
core-collapse supernovae in Arp 220 are highly luminous, possibly implying a radically different
stellar initial mass function (IMF) or stellar evolution compared to galactic disks. A second group
of sources, consisting of the brightest and longest monitored sources at 18 cm, do not easily fit
the radio supernova model. We propose that these are young supernova remnants that have just
begun interacting with their surrounding dense ISM
A critical narrative analysis of shared decision-making in acute, inpatient mental health care
Shared decision-making (SDM) is a high priority in healthcare policy and is complementary to the recovery philosophy in mental health care. This agenda has been operationalised within the Values-Based Practice (VBP) framework, which offers a theoretical and practical model to promote democratic interprofessional approaches to decision-making. However, these are limited by a lack of recognition of the implications of power implicit within the mental health system. This study considers issues of power within the context of decision-making and examines to what extent decisions about patients? care on acute in-patient wards are perceived to be shared. Focus groups were conducted with 46 mental health professionals, service users, and carers. The data were analysed using the framework of critical narrative analysis (CNA). The findings of the study suggested each group constructed different identity positions, which placed them as inside or outside of the decision-making process. This reflected their view of themselves as best placed to influence a decision on behalf of the service user. In conclusion, the discourse of VBP and SDM needs to take account of how differentials of power and the positioning of speakers affect the context in which decisions take place
Multiwavelength radio observations of the compact starburst in Arp 220
We report the first detection at multiple radio wavelengths (13, 6, and 3.6 cm) of 18 compact
sources within both nuclei of the Ultra Luminous Infra-Red Galaxy (ULIRG) Arp 220. In just
over half of the sources we find that the observed spectra are consistent with the standard model
of powerful Type IIn supernovae interacting with their pre-explosion stellar wind. The rate of appearance
of new radio sources ascribed to these supernova events suggests that a large fraction of
core-collapse supernovae in Arp 220 are highly luminous, possibly implying a radically different
stellar initial mass function (IMF) or stellar evolution compared to galactic disks. A second group
of sources, consisting of the brightest and longest monitored sources at 18 cm, do not easily fit
the radio supernova model. We propose that these are young supernova remnants that have just
begun interacting with their surrounding dense ISM
The radio spectra of the compact sources in Arp 220: A mixed population of supernovae and supernova remnants
We report the first detection at multiple radio wavelengths (13, 6 and 3.6
cm) of the compact sources within both nuclei of the Ultra Luminous Infra-Red
Galaxy Arp 220. We present the radio spectra of the 18 detected sources. In
just over half of the sources we find that these spectra and other properties
are consistent with the standard model of powerful Type IIn supernovae
interacting with their pre-explosion stellar wind. The rate of appearance of
new radio sources identified with these supernova events suggests that an
unusually large fraction of core collapse supernovae in Arp 220 are highly
luminous; possibly implying a radically different stellar initial mass function
or stellar evolution compared to galactic disks. Another possible explanation
invokes very short (~3 x 10^5 year) intense (~10^3 M_Sol year^-1) star
formation episodes with a duty cycle of ~10%. A second group of our detected
sources, consisting of the brightest and longest monitored sources at 18 cm do
not easily fit the radio supernova model. These sources show a range of
spectral indexes from -0.2 to -1.9. We propose that these are young supernova
remnants which have just begun interacting with a surrounding ISM with a
density between 10^4 and 10^5 cm^-3. One of these sources is probably resolved
at 3.6 cm wavelength with a diameter 0.9 pc. In the western nucleus we estimate
that the ionized component of the ISM gives rise to foreground free-free
absorption with opacity at 18 cm of <0.6 along the majority of lines of sight.
Other sources may be affected by absorption with opacity in the range 1 to 2.
These values are consistent with previous models as fitted to the radio
recombination lines and the continuum spectrum.Comment: 44 pages, 9 figures, 2 tables. Accepted for publication in Ap
The 6-GHz methanol multibeam maser catalogue - I. Galactic Centre region, longitudes 345? to 6?
We have conducted a Galactic plane survey of methanol masers at 6668 MHz using a sevenbeam receiver on the Parkes telescope. Here we present results from the first part, which
provides sensitive unbiased coverage of a large region around the Galactic Centre. Details are
given for 183 methanol maser sites in the longitude range 345⊠through the Galactic Centre to
6âŠ. Within 6⊠of the Galactic Centre, we found 88 maser sites, of which more than half (48)
are new discoveries. The masers are confined to a narrow Galactic latitude range, indicative
of many sources at the Galactic Centre distance and beyond, and confined to a thin disc
population; there is no high-latitude population that might be ascribed to the Galactic bulge.
Within 2⊠of the Galactic Centre the maser velocities all lie between â60 and +77 km sâ1,
a range much smaller than the 540 km sâ1 range observed in CO. Elsewhere, the maser with
highest positive velocity (+107 km sâ1) occurs, surprisingly, near longitude 355⊠and is probably attributable to the Galactic bar. The maser with the most negative velocity (â127 km sâ1)
is near longitude 346âŠ, within the longitudeâvelocity locus of the near side of the â3-kpc armâ.
It has the most extreme velocity of a clear population of masers associated with the near and
far sides of the 3-kpc arm. Closer to the Galactic Centre the maser space density is generally
low, except within 0.25 kpc of the Galactic Centre itself, the âGalactic Centre zoneâ, where
it is 50 times higher, which is hinted at by the longitude distribution, and confirmed by the
unusual velocities.AA and DW-McS acknowledge support from a Science and Technology Facilities Council (STFC) studentship. LQ acknowledges
support from the EU Framework 6 Marie Curie Early Stage Training programme under contract MEST-CT-2005-19669 âESTRELAâ
Selenoprotein gene nomenclature
The human genome contains 25 genes coding for selenocysteine-containing proteins (selenoproteins). These proteins are involved in a variety of functions, most notably redox homeostasis. Selenoprotein enzymes with known functions are designated according to these functions: TXNRD1, TXNRD2, and TXNRD3 (thioredoxin reductases), GPX1, GPX2, GPX3, GPX4 and GPX6 (glutathione peroxidases), DIO1, DIO2, and DIO3 (iodothyronine deiodinases), MSRB1 (methionine-R-sulfoxide reductase 1) and SEPHS2 (selenophosphate synthetase 2). Selenoproteins without known functions have traditionally been denoted by SEL or SEP symbols. However, these symbols are sometimes ambiguous and conflict with the approved nomenclature for several other genes. Therefore, there is a need to implement a rational and coherent nomenclature system for selenoprotein-encoding genes. Our solution is to use the root symbol SELENO followed by a letter. This nomenclature applies to SELENOF (selenoprotein F, the 15 kDa selenoprotein, SEP15), SELENOH (selenoprotein H, SELH, C11orf31), SELENOI (selenoprotein I, SELI, EPT1), SELENOK (selenoprotein K, SELK), SELENOM (selenoprotein M, SELM), SELENON (selenoprotein N, SEPN1, SELN), SELENOO (selenoprotein O, SELO), SELENOP (selenoprotein P, SeP, SEPP1, SELP), SELENOS (selenoprotein S, SELS, SEPS1, VIMP), SELENOT (selenoprotein T, SELT), SELENOV (selenoprotein V, SELV) and SELENOW (selenoprotein W, SELW, SEPW1). This system, approved by the HUGO Gene Nomenclature Committee, also resolves conflicting, missing and ambiguous designations for selenoprotein genes and is applicable to selenoproteins across vertebrates
Assessing Human Exposure to SVOCs in Materials, Products, and Articles : A Modular Mechanistic Framework
A critical review of the current state of knowledge of chemical emissions from indoor sources, partitioning among indoor compartments, and the ensuing indoor exposure leads to a proposal for a modular mechanistic framework for predicting human exposure to semivolatile organic compounds (SVOCs). Mechanistically consistent source emission categories include solid, soft, frequent contact, applied, sprayed, and high temperature sources. Environmental compartments are the gas phase, airborne particles, settled dust, indoor surfaces, and clothing. Identified research needs are the development of dynamic emission models for several of the source emission categories and of estimation strategies for critical model parameters. The modular structure of the framework facilitates subsequent inclusion of new knowledge, other chemical classes of indoor pollutants, and additional mechanistic processes relevant to human exposure indoors. The framework may serve as the foundation for developing an open-source community model to better support collaborative research and improve access for application by stakeholders. Combining exposure estimates derived using this framework with toxicity data for different end points and toxicokinetic mechanisms will accelerate chemical risk prioritization, advance effective chemical management decisions, and protect public health.Peer reviewe
- âŠ