1,180 research outputs found
Dust effects on the derived Sersic indexes of disks and bulges in spiral galaxies
We present a theoretical study that quantifies the effect of dust on the
derived Sersic indexes of disks and bulges. The changes in the derived
parameters from their intrinsic values (as seen in the absence of dust) were
obtained by fitting Sersic distributions on simulated images of disks and
bulges produced using radiative transfer calculations and the model of Popescu
et al. 2011. We found that dust has the effect of lowering the measured Sersic
index in most cases, with stronger effects for disks and bulges seen through
more optically thick lines of sight.Comment: 3 pages, 2 figures, to appear in the Proceedings of the IAU Symposium
No.284, "The Spectral Energy Distribution of Galaxies", 5-9 sept. 2011,
editors Richard J. Tuffs and Cristina C. Popesc
GROUND REACTION FORCES OF VARIATIONS OF PLYOMETRIC EXERCISES ON HARD SURFACES, PADDED SURFACES AND IN WATER
Subjects performed drop jumps from 46 cm, a single leg jump, counter movement jump, and squat jump on a hard surface, wrestling mat and in water. Ground reaction force data obtained via a force platform were used to determine the time to takeoff, takeoff peak ground reaction force, power, jump height, and landing peak ground reaction force. A one way repeated measures ANOVA demonstrated differences between plyometic exercises assessed for all of the variables assessed (P ≤ 0.05), with post hoc analysis demonstrating the specific differences. Results indicate that the hard surface and mat conditions were similar for almost all of the plyometric exercises assessed for most outcome variables whereas the plyometric exercises performed in water were different than those performed on the hard surface or mat in most cases
Overseas GP recruitment: comparing international GP training with the UK and ensuring that registration standards and patient safety are maintained
This is the final version. Available from Royal College of General Practitioners via the DOI in this record.Background Ambitious overseas recruitment targets have been set by the UK government to help alleviate the current GP shortage. European Economic Area (EEA) doctors can join the UK’s GP register under European law. Non-EEA doctors must obtain a Certificate of Eligibility for General Practice Registration (CEGPR), demonstrating equivalence to UK-trained doctors. CEGPR applications can be time-consuming and burdensome. To meet overseas recruitment targets, it is important to facilitate the most efficient route into UK general practice while maintaining registration standards and patient safety.
Aim To develop a methodology to map postgraduate GP training and healthcare contextual data from an overseas country to the UK.
Design & setting Desk-based research and stakeholder interviews.
Method Four stages were undertaken: 1) developing a data collection template; 2) conducting a case study (using Australia as a test case); 3) refining the data collection template; and 4) creating a mapping framework. The case study used the 2016 curricula for the UK and Australia.
Results Five ‘domains’ were identified: healthcare context, training pathway, curriculum, assessment, and continuing professional development (CPD) and revalidation. The final data collection template comprised 49 mapping items across the domains. The methodology incorporated the application of a red, amber, or green (RAG) rating to indicate similarity of data across the five domains. Australia was rated ‘green’ for training pathway, curriculum, and assessment, and ‘amber’ for healthcare context and CPD and revalidation. The overall rating was ‘green’.
Conclusion Implementing this systematic methodology for mapping GP training between countries may support the UK’s ambitions to recruit more GPs, and alleviate current GP workforce pressures.NHS Englan
The Cold and Hot Gas Content of Fine-Structure E and S0 Galaxies
We investigate trends of the cold and hot gas content of early-type galaxies
with the presence of optical morphological peculiarities, as measured by the
fine-structure index (Sigma). HI mapping observations from the literature are
used to track the cold-gas content, and archival ROSAT PSPC data are used to
quantify the hot-gas content. We find that E and S0 galaxies with a high
incidence of optical peculiarities are exclusively X-ray underluminous and,
therefore, deficient in hot gas. In contrast, more relaxed galaxies with little
or no signs of optical peculiarities span a wide range of X-ray luminosities.
That is, the X-ray excess anticorrelates with Sigma. There appears to be no
similar trend of cold-gas content with either fine-structure index or X-ray
content. The fact that only apparently relaxed E and S0 galaxies are strong
X-ray emitters is consistent with the hypothesis that after strong disturbances
such as a merger hot-gas halos build up over a time scale of several gigayears.
This is consistent with the expected mass loss from stars.Comment: 12 pages, latex, 5 figures. Accepted for publication in A
Diversity of new Martian crater clusters informs meteoroid atmospheric interactions
We investigated 634 crater clusters on Mars detected between 2007 and 2021,
which represent more than half of all impacts discovered in this period. Crater
clusters form when meteoroids in the 10 kg to 10 ton mass range break-up in
Mars' atmosphere to produce a few to a few hundred fragments that hit the
ground. The properties of the clusters can inform our understanding of
meteoroid properties and the processes that govern their fragmentation. We
mapped individual craters 1 m within each cluster and defined a range of
cluster properties based on the spatial and size distributions of the craters.
The large data set, with over eight times more cluster observations than
previous work, provides a more robust statistical investigation of crater
cluster parameters and their correlations. Trends in size, dispersion and large
crater fraction with elevation support weak atmospheric filtering of material.
The diversity in the number of individual craters within a cluster, and their
size-frequency distributions, may reflect either a diversity in fragmentation
style, fragility or internal particle sizes.Comment: 12 pages, 12 figures at the en
The stellar populations in the low-luminosity, early-type galaxy NGC59
Low luminosity galaxies may be the building blocks of more luminous systems. Southern African Large Telescope (SALT) observations of the low luminosity, early-type galaxy NGC59 are obtained and analysed. These data are used to measure the stellar population parameters in the centre and off-centre regions of this galaxy, in order to uncover its likely star formation history. We find evidence of older stars, in addition to young stars in the emission line regions. The metallicity of the stellar population is constrained to be [Z/H] ~ -1.1 to -1.6, which is extremely low, even for this low luminosity galaxy, since it is not classed as a dwarf spheroidal galaxy. The measured [alpha/Fe] ratio is sub-solar, which indicates an extended star formation history in NGC59. If such objects formed the building blocks of more massive, early-type galaxies, then they must have been gaseous mergers, rather than dry mergers, in order to increase the metals to observed levels in luminous, early-type galaxies
Cross-species analysis of genetically engineered mouse models of MAPK-driven colorectal cancer identifies hallmarks of the human disease
Effective treatment options for advanced colorectal cancer (CRC) are limited, survival rates are poor and this disease continues to be a leading cause of cancer-related deaths worldwide. Despite being a highly heterogeneous disease, a large subset of individuals with sporadic CRC typically harbor relatively few established ‘driver’ lesions. Here, we describe a collection of genetically engineered mouse models (GEMMs) of sporadic CRC that combine lesions frequently altered in human patients, including well-characterized tumor suppressors and activators of MAPK signaling. Primary tumors from these models were profiled, and individual GEMM tumors segregated into groups based on their genotypes. Unique allelic and genotypic expression signatures were generated from these GEMMs and applied to clinically annotated human CRC patient samples. We provide evidence that a Kras signature derived from these GEMMs is capable of distinguishing human tumors harboring KRAS mutation, and tracks with poor prognosis in two independent human patient cohorts. Furthermore, the analysis of a panel of human CRC cell lines suggests that high expression of the GEMM Kras signature correlates with sensitivity to targeted pathway inhibitors. Together, these findings implicate GEMMs as powerful preclinical tools with the capacity to recapitulate relevant human disease biology, and support the use of genetic signatures generated in these models to facilitate future drug discovery and validation efforts
H-ATLAS/GAMA and HeViCS – dusty early-type galaxies in different environments
The Herschel Space Observatory has had a tremendous impact on the study of extragalactic dust. Specifically, early-type galaxies (ETG) have been the focus of several studies. In this paper, we combine results from two Herschel studies – a Virgo cluster study Herschel Virgo Cluster Survey (HeViCS) and a broader, low-redshift Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS)/Galaxy and Mass Assembly (GAMA) study – and contrast the dust and associated properties for similar mass galaxies. This comparison is motivated by differences in results exhibited between multiple Herschel studies of ETG. A comparison between consistent modified blackbody derived dust mass is carried out, revealing strong differences between the two samples in both dust mass and dust-to-stellar mass ratio. In particular, the HeViCS sample lacks massive ETG with as high a specific dust content as found in H-ATLAS. This is most likely connected with the difference in environment for the two samples. We calculate nearest neighbour environment densities in a consistent way, showing that H-ATLAS ETG occupy sparser regions of the local Universe, whereas HeViCS ETG occupy dense regions. This is also true for ETG that are not Herschel-detected but are in the Virgo and GAMA parent samples. Spectral energy distributions are fit to the panchromatic data. From these, we find that in H-ATLAS the specific star formation rate anticorrelates with stellar mass and reaches values as high as in our Galaxy. On the other hand HeViCS ETG appear to have little star formation. Based on the trends found here, H-ATLAS ETG are thought to have more extended star formation histories and a younger stellar population than HeViCS ETG
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