852 research outputs found
Recommended from our members
Winning and losing in the creative industries: an analysis of creative graduates' career opportunities across creative disciplines
Following earlier work looking at overall career difficulties and low economic rewards faced by graduates in creative disciplines, the paper takes a closer look into the different career patterns and economic performance of âBohemianâ graduates across different creative disciplines. While it is widely acknowledged in the literature that careers in the creative field tend to be unstructured, often relying on part-time work and low wages, our knowledge of how these characteristics differ across the creative industries and occupational sectors is very limited. The paper explores the different trajectory and career patterns experienced by graduates in different creative disciplinary fields and their ability to enter creative occupations. Data from the Higher Education Statistical Agency (HESA) are presented, articulating a complex picture of the reality of finding a creative occupation for creative graduates. While students of some disciplines struggle to find full-time work in the creative economy, for others full-time occupation is the norm. Geography plays a crucial role also in offering graduates opportunities in creative occupations and higher salaries. The findings are contextualised in the New Labour cultural policy framework and conclusions are drawn on whether the creative industries policy construct has hidden a very problematic reality of winners and losers in the creative economy
A search for rapidly pulsating hot subdwarf stars in the GALEX survey
NASA's Galaxy Evolution Explorer (GALEX) provided near- and far-UV
observations for approximately 77 percent of the sky over a ten-year period;
however, the data reduction pipeline initially only released single NUV and FUV
images to the community. The recently released Python module gPhoton changes
this, allowing calibrated time-series aperture photometry to be extracted
easily from the raw GALEX data set. Here we use gPhoton to generate light
curves for all hot subdwarf B (sdB) stars that were observed by GALEX, with the
intention of identifying short-period, p-mode pulsations. We find that the
spacecraft's short visit durations, uneven gaps between visits, and dither
pattern make the detection of hot subdwarf pulsations difficult. Nonetheless,
we detect UV variations in four previously known pulsating targets and report
their UV pulsation amplitudes and frequencies. Additionally, we find that
several other sdB targets not previously known to vary show promising signals
in their periodograms. Using optical follow-up photometry with the Skynet
Robotic Telescope Network, we confirm p-mode pulsations in one of these
targets, LAMOST J082517.99+113106.3, and report it as the most recent addition
to the sdBVr class of variable stars.Comment: 11 Pages, 8 Figures, Accepted for publication in the Astrophysical
Journa
High Spectral Resolution Measurement of the SunyaevâZel'dovich Effect Null with Z-Spec
The Sunyaev-Zel'dovich (SZ) effect spectrum crosses through a null where ÎT_CMB = 0 near Îœ_0 = 217 GHz. In a cluster of galaxies, Îœ0 can be shifted from the canonical thermal SZ effect value by corrections to the SZ effect scattering due to the properties of the inter-cluster medium. We have measured the SZ effect in the hot galaxy cluster RX J 1347.5 â 1145 with Z-Spec, an R ~ 300 grating spectrometer sensitive between 185 and 305 GHz. These data comprise a high spectral resolution measurement around the null of the SZ effect and clearly exhibit the transition from negative to positive ÎT_CMB over the Z-Spec band. The SZ null position is measured to be Îœ_0 = 225.8 ± 2.5(stat.) ± 1.2(sys.) GHz, which differs from the canonical null frequency by 3.0Ï and is evidence for modifications to the canonical thermal SZ effect shape. Assuming the measured shift in Îœ0 is due only to relativistic corrections to the SZ spectrum, we place the limit kT_e = 17.1 ± 5.3 keV from the zero-point measurement alone. By simulating the response of the instrument to the sky, we are able to generate likelihood functions in {y_0, T_e, v_pec} space. For v_pec = 0 km s^(â1), we measure the best-fitting SZ model to be y_0 = 4.6^(+0.6)_(â0.9) Ă 10^(â4), T_e, 0 = 15.2^(+12)_(â7.4) keV. When v pec is allowed to vary, a most probable value of v_pec = + 450 ± 810 km s^(â1) is found
Feedback under the microscope II: heating, gas uplift, and mixing in the nearest cluster core
Using a combination of deep 574ks Chandra data, XMM-Newton high-resolution
spectra, and optical Halpha+NII images, we study the nature and spatial
distribution of the multiphase plasma in M87. Our results provide direct
observational evidence of `radio mode' AGN feedback in action, stripping the
central galaxy of its lowest entropy gas and preventing star-formation. This
low entropy gas was entrained with and uplifted by the buoyantly rising
relativistic plasma, forming long "arms". These arms are likely oriented within
15-30 degrees of our line-of-sight. The mass of the uplifted gas in the arms is
comparable to the gas mass in the approximately spherically symmetric 3.8 kpc
core, demonstrating that the AGN has a profound effect on its immediate
surroundings. The coolest X-ray emitting gas in M87 has a temperature of ~0.5
keV and is spatially coincident with Halpha+NII nebulae, forming a multiphase
medium where the cooler gas phases are arranged in magnetized filaments. We
place strong upper limits of 0.06 Msun/yr on the amount of plasma cooling
radiatively from 0.5 keV and show that a uniform, volume-averaged heating
mechanism could not be preventing the cool gas from further cooling. All of the
bright Halpha filaments appear in the downstream region of the <3 Myr old shock
front, at smaller radii than ~0.6'. We suggest that shocks induce shearing
around the filaments, thereby promoting mixing of the cold gas with the ambient
hot ICM via instabilities. By bringing hot thermal particles into contact with
the cool, line-emitting gas, mixing can supply the power and ionizing particles
needed to explain the observed optical spectra. Mixing of the coolest X-ray
emitting plasma with the cold optical line emitting filamentary gas promotes
efficient conduction between the two phases, allowing non-radiative cooling
which could explain the lack of X-ray gas with temperatures under 0.5 keV.Comment: to appear in MNRA
Obesity-associated gut microbiota is enriched in Lactobacillus reuteri and depleted in Bifidobacterium animalis and Methanobrevibacter smithii
Background: Obesity is associated with increased health risk and has been associated with alterations in bacterial gut microbiota, with mainly a reduction in Bacteroidetes, but few data exist at the genus and species level. It has been reported that the Lactobacillus and Bifidobacterium genus representatives may have a critical role in weight regulation as an anti-obesity effect in experimental models and humans, or as a growth-promoter effect in agriculture depending on the strains. Objectives and methods: To confirm reported gut alterations and test whether Lactobacillus or Bifidobacterium species found in the human gut are associated with obesity or lean status, we analyzed the stools of 68 obese and 47 controls targeting Firmicutes, Bacteroidetes, Methanobrevibacter smithii, Lactococcus lactis, Bifidobacterium animalis and seven species of Lactobacillus by quantitative PCR (qPCR) and culture on a Lactobacillus-selective medium. Findings: In qPCR, B. animalis (odds ratio (OR) 0.63; 95% confidence interval (CI) 0.39-1.01; P = 0.056) and M. smithii (OR = 0.76; 95% CI 0.59-0.97; P = 0.03) were associated with normal weight whereas Lactobacillus reuteri (OR = 1.79; 95% CI 1.03-3.10; P = 0.04) was associated with obesity. Conclusion: The gut microbiota associated with human obesity is depleted in M. smithii. Some Bifidobacterium or Lactobacillus species were associated with normal weight (B. animalis) while others (L. reuteri) were associated with obesity. Therefore, gut microbiota composition at the species level is related to body weight and obesity, which might be of relevance for further studies and the management of obesity. These results must be considered cautiously because it is the first study to date that links specific species of Lactobacillus with obesity in humans. International Journal of Obesity (2012) 36, 817-825; doi:10.1038/ijo.2011.153; published online 9 August 201
Graduate views on access to higher education: is it really a case of pulling up the ladder?
Using as a starting point in the recent work of Mountford-Zimdars et al., the authors analyse attitudes towards expanding higher education (HE) opportunities in the UK. The authors propose that the approach of Mountford-Zimdars et al. is flawed not only in its adoption of a multivariate logistic regression but also in its interpretation of results. The authors make a number of adaptations, chief among them being the use of an ordered probit approach and the addition of a time dimension to test for changes in attitudes between 2000 and 2010. The authors find that attitudes towards HE expansion have intensified during the decade 2000â2010, but the authors uncover no evidence that this is due to graduates wanting to âpull up the ladderâ, as suggested by Mountford-Zimdars et al. The authors argue that evidence of a widespread desire to reduce access to HE can most likely be explained by social congestion theory, internal institutional disaffection and rising tuition fees
Extreme AGN Feedback and Cool Core Destruction in the X-ray Luminous Galaxy Cluster MACS J1931.8-2634
We report on a deep, multiwavelength study of the galaxy cluster MACS
J1931.8-2634 using Chandra X-ray, Subaru optical, and VLA 1.4 GHz radio data.
This cluster (z=0.352) harbors one of the most X-ray luminous cool cores yet
discovered, with an equivalent mass cooling rate within the central 50 kpc is
approximately 700 solar masses/yr. Unique features observed in the central core
of MACSJ1931.8-2634 hint to a wealth of past activity that has greatly
disrupted the original cool core. We observe a spiral of relatively cool,
dense, X-ray emitting gas connected to the cool core, as well as highly
elongated intracluster light (ICL) surrounding the cD galaxy. Extended radio
emission is observed surrounding the central AGN, elongated in the east-west
direction, spatially coincident with X-ray cavities. The power input required
to inflate these `bubbles' is estimated from both the X-ray and radio emission
to reside between 4 and 14e45 erg/s, putting it among the most powerful jets
ever observed. This combination of a powerful AGN outburst and bulk motion of
the cool core have resulted in two X-ray bright ridges to form to the north and
south of the central AGN at a distance of approximately 25 kpc. The northern
ridge has spectral characteristics typical of cool cores and is consistent with
being a remnant of the cool core after it was disrupted by the AGN and bulk
motions. It is also the site of H-alpha filaments and young stars. The X-ray
spectroscopic cooling rate associated with this ridge is approximately 165
solar masses/yr, which agrees with the estimate of the star formation rate from
broad-band optical imaging (170 solar masses/yr). MACS J1931.8-2634 appears to
harbor one of most profoundly disrupted low entropy cores observed in a
cluster, and offers new insights into the survivability of cool cores in the
context of hierarchical structure formation.Comment: 19 pages, 15 figures, 5 tables. Accepted by MNRAS for publication
September 30 201
Identification and rejection of scattered neutrons in AGATA
Gamma rays and neutrons, emitted following spontaneous fission of 252Cf, were
measured in an AGATA experiment performed at INFN Laboratori Nazionali di
Legnaro in Italy. The setup consisted of four AGATA triple cluster detectors
(12 36-fold segmented high-purity germanium crystals), placed at a distance of
50 cm from the source, and 16 HELENA BaF2 detectors. The aim of the experiment
was to study the interaction of neutrons in the segmented high-purity germanium
detectors of AGATA and to investigate the possibility to discriminate neutrons
and gamma rays with the gamma-ray tracking technique. The BaF2 detectors were
used for a time-of-flight measurement, which gave an independent discrimination
of neutrons and gamma rays and which was used to optimise the gamma-ray
tracking-based neutron rejection methods. It was found that standard gamma-ray
tracking, without any additional neutron rejection features, eliminates
effectively most of the interaction points due to recoiling Ge nuclei after
elastic scattering of neutrons. Standard tracking rejects also a significant
amount of the events due to inelastic scattering of neutrons in the germanium
crystals. Further enhancements of the neutron rejection was obtained by setting
conditions on the following quantities, which were evaluated for each event by
the tracking algorithm: energy of the first and second interaction point,
difference in the calculated incoming direction of the gamma ray,
figure-of-merit value. The experimental results of tracking with neutron
rejection agree rather well with Geant4 simulations
On the DM interpretation of the origin of non-thermal phenomena in galaxy clusters
(Abridged) We study the predictions of various annihilating Dark Matter (DM)
models in order to interpret the origin of non-thermal phenomena in galaxy
clusters. We consider three neutralino DM models with light (9 GeV),
intermediate (60 GeV) and high (500 GeV) mass. The secondary particles created
by neutralino annihilation produce a multi-frequency Spectral Energy
Distribution (SED), as well as heating of the intracluster gas, that are tested
against the observations available for the Coma cluster. The DM produced SEDs
are normalized to the Coma radio halo spectrum. We find that it is not possible
to interpret all non-thermal phenomena observed in Coma in terms of DM
annihilation. The DM model with 9 GeV mass produces too small power at all
frequencies, while the DM model with 500 GeV produces a large excess power at
all frequencies. The DM model with 60 GeV and composition is
consistent with the HXR and gamma-ray data but fails to reproduce the EUV and
soft X-ray data. The DM model with 60 GeV and composition is always
below the observed fluxes. The radio halo spectrum of Coma is well fitted only
in the or light and intermediate mass DM models. The heating
produced by DM annihilation in the center of Coma is always larger than the
intracluster gas cooling rate for an NFW DM density profile and it is
substantially smaller than the cooling rate only for a cored DM density profile
in DM model with 9 GeV. We conclude that the possibility of interpreting the
origin of non-thermal phenomena in galaxy clusters with DM annihilation models
requires a low neutralino mass and a cored DM density profile. If we then
consider the multimessenger constraints to the neutralino annihilation
cross-section, it turns out that such scenario would also be excluded unless we
introduce a substantial boost factor due to the presence of DM substructures.Comment: 9 pages, 6 figures, 2 Tables. Submitted to A&
- âŠ