1,348 research outputs found
Long-term high fat feeding of rats results in increased numbers of circulating microvesicles with pro-inflammatory effects on endothelial cells
Obesity and type 2 diabetes lead to dramatically increased risks of atherosclerosis and CHD. Multiple mechanisms converge to promote atherosclerosis by increasing endothelial oxidative stress and up-regulating expression of pro-inflammatory molecules. Microvesicles (MV) are small ( < 1 μm) circulating particles that transport proteins and genetic material, through which they are able to mediate cell–cell communication and influence gene expression. Since MV are increased in plasma of obese, insulin-resistant and diabetic individuals, who often exhibit chronic vascular inflammation, and long-term feeding of a high-fat diet (HFD) to rats is a well-described model of obesity and insulin resistance, we hypothesised that this may be a useful model to study the impact of MV on endothelial inflammation. The number and cellular origin of MV from HFD-fed obese rats were characterised by flow cytometry. Total MV were significantly increased after feeding HFD compared to feeding chow (P< 0·001), with significantly elevated numbers of MV derived from leucocyte, endothelial and platelet compartments (P< 0·01 for each cell type). MV were isolated from plasma and their ability to induce reactive oxygen species (ROS) formation and vascular cell adhesion molecule (VCAM)-1 expression was measured in primary rat cardiac endothelial cells in vitro. MV from HFD-fed rats induced significant ROS (P< 0·001) and VCAM-1 expression (P= 0·0275), indicative of a pro-inflammatory MV phenotype in this model of obesity. These findings confirm that this is a useful model to further study the mechanisms by which diet can influence MV release and subsequent effects on cardio-metabolic health
In the Interests of clients or commerce? Legal aid, supply, demand, and 'ethical indeterminacy' in criminal defence work
As a professional, a lawyer's first duty is to serve the client's best interests, before simple monetary gain. In criminal defence work, this duty has been questioned in the debate about the causes of growth in legal aid spending: is it driven by lawyers (suppliers) inducing unnecessary demand for their services or are they merely responding to increased demand? Research reported here found clear evidence of a change in the handling of cases in response to new payment structures, though in ways unexpected by the policy's proponents. The paper develops the concept of 'ethical indeterminacy' as a way of understanding how defence lawyers seek to reconcile the interests of commerce and clients. Ethical indeterminacy suggests that where different courses of action could each be said to benefit the client, the lawyer will tend to advise the client to decide in the lawyer's own interests. Ethical indeterminacy is mediated by a range of competing conceptions of 'quality' and 'need'. The paper goes on to question the very distinction between 'supply' and 'demand' in the provision of legal services
The PULSE@Parkes project: A new observing technique for long-term pulsar monitoring
The PULSE@Parkes project has been designed to monitor the rotation of radio
pulsars over time spans of days to years. The observations are obtained using
the Parkes 64-m and 12-m radio telescopes by Australian and international high
school students. These students learn the basis of radio astronomy and
undertake small projects with their observations. The data are fully calibrated
and obtained with the state-of-the-art pulsar hardware available at Parkes. The
final data sets are archived and are currently being used to carry out studies
of 1) pulsar glitches, 2) timing noise, 3) pulse profile stability over long
time scales and 4) the extreme nulling phenomenon. The data are also included
in other projects such as gamma-ray observatory support and for the Parkes
Pulsar Timing Array project. In this paper we describe the current status of
the project and present the first scientific results from the Parkes 12-m radio
telescope. We emphasise that this project offers a straightforward means to
enthuse high school students and the general public about radio astronomy while
obtaining scientifically valuable data sets.Comment: accepted for publication by PAS
Deep LOFAR observations of the merging galaxy cluster CIZA J2242.8+5301
Previous studies have shown that CIZA J2242.8+5301 (the 'Sausage' cluster, z = 0.192) is a massive merging galaxy cluster that hosts a radio halo and multiple relics. In this paper, we present deep, high-fidelity, low-frequency images made with the LOw-Frequency Array (LOFAR) between 115.5 and 179 MHz. These images, with a noise of 140 μJy beam- 1 and a resolution of θbeam = 7.3 arcsec × 5.3 arcsec, are an order of magnitude more sensitive and five times higher resolution than previous low-frequency images of this cluster. We combined the LOFAR data with the existing Giant Metrewave Radio Telescope (GMRT) (153, 323, 608 MHz) and Westerbork Synthesis Radio Telescope (WSRT) (1.2, 1.4, 1.7, 2.3 GHz) data to study the spectral properties of the radio emission from the cluster. Assuming diffusive shock acceleration (DSA), we found Mach numbers of Mn=2.7{}_{-0.3}^{+0.6} and Ms=1.9_{-0.2}^{+0.3} for the northern and southern shocks. The derived Mach number for the northern shock requires an acceleration efficiency of several percent to accelerate electrons from the thermal pool, which is challenging for DSA. Using the radio data, we characterized the eastern relic as a shock wave propagating outwards with a Mach number of Me=2.4_{-0.3}^{+0.5}, which is in agreement with MeX=2.5{}_{-0.2}^{+0.6} that we derived from Suzaku data. The eastern shock is likely to be associated with the major cluster merger. The radio halo was measured with a flux of 346 ± 64 mJy at 145 MHz. Across the halo, we observed a spectral index that remains approximately constant (α ^{145 MHz-2.3 GHz}_{{across ˜ 1 Mpc}^2}=-1.01± 0.10) after the steepening in the post-shock region of the northern relic. This suggests a generation of post-shock turbulence that re-energies aged electrons
Mediation in the Law Curriculum
Cited by Lord Neuberger in ‘Educating Future Mediators’ at the 4th Civil Mediation Council National Conference, May 201
The nature of the low-frequency emission of M51: First observations of a nearby galaxy with LOFAR
The grand-design spiral galaxy M51 was observed with the LOFAR High Frequency
Antennas (HBA) and imaged in total intensity and polarisation. This observation
covered the frequencies between 115 MHz and 175 MHz. We produced an image of
total emission of M51 at the mean frequency of 151 MHz with 20 arcsec
resolution and 0.3 mJy rms noise, which is the most sensitive image of a galaxy
at frequencies below 300 MHz so far. The integrated spectrum of total radio
emission is described well by a power law, while flat spectral indices in the
central region indicate thermal absorption. We observe that the disk extends
out to 16 kpc and see a break in the radial profile near the optical radius of
the disk. Our main results, the scale lengths of the inner and outer disks at
151 MHz and 1.4 GHz, arm--interarm contrast, and the break scales of the
radio--far-infrared correlations, can be explained consistently by CRE
diffusion, leading to a longer propagation length of CRE of lower energy. The
distribution of CRE sources drops sharply at about 10 kpc radius, where the
star formation rate also decreases sharply. We find evidence that thermal
absorption is primarily caused by HII regions. The non-detection of
polarisation from M51 at 151 MHz is consistent with the estimates of Faraday
depolarisation. Future searches for polarised emission in this frequency range
should concentrate on regions with low star formation rates.Comment: 20 pages, 18 figures, accepted for publication in A&
Structural Evolution of a Composite Middle to Lower Crustal Section: The Sierra de Pie de Palo, Northwest Argentina
The Sierra de Pie de Palo of northwest Argentina preserves middle to lower crustal metamorphic rocks that were penetratively deformed during Ordovician accretion of the Precordillera terrane to the Gondwana margin. New structural, petrologic, and geochronologic data from a 40 km structural transect reveals that the Sierra de Pie de Palo preserves a middle to lower crustal ductile thrust complex consisting of individual structural units and not an intact ophiolite and cover sequence. Top-to-the-west thrusting occurred intermittently on discrete ductile shear zones from ∼515 to ∼417 Ma and generally propagated toward the foreland with progressive deformation. Ordovician crustal shortening and peak metamorphic temperatures in the central portion of the Sierra de Pie de Palo were synchronous with retro-arc shortening and magmatic flare-up within the Famatina arc. Accretion of the Precordillera terrane resulted in the end of arc flare-up and the onset of synconvergent extension by ∼439 Ma. Continued synextensional to postextensional convergence was accommodated along progressively lower grade shear zones following terrane accretion and the establishment of a new plate margin west of the Precordillera terrane. The results support models of Cordilleran orogens that link voluminous arc magmatism to periods of regional shortening. The deformation, metamorphic, and magmatic history within the Sierra de Pie de Palo is consistent with models placing the region adjacent to the Famatina margin in the middle Cambrian and not as basement to the Precordillera terrane
On the vertical distribution of smoke in the Amazonian atmosphere during the dry season
PublishedLidar observations of smoke aerosols have been analysed from six flights of the Facility for Airborne Atmospheric Measurements BAe-146 research aircraft over Brazil during the biomass burning season (September 2012). A large aerosol optical depth (AOD) was observed, typically ranging 0.4–0.9, along with a typical aerosol extinction coefficient of 100–400 Mm−1. The data highlight the persistent and widespread nature of the Amazonian haze, which had a consistent vertical structure, observed over a large distance ( ∼ 2200 km) during a period of 14 days. Aerosols were found near the surface; but the larger aerosol load was typically found in elevated layers that extended from 1–1.5 to 4–6 km. The measurements have been compared to model predictions with the Met Office Unified Model (MetUM) and the ECMWF-MACC model. The MetUM generally reproduced the vertical structure of the Amazonian haze observed with the lidar. The ECMWF-MACC model was also able to reproduce the general features of smoke plumes albeit with a small overestimation of the AOD. The models did not always capture localised features such as (i) smoke plumes originating from individual fires, and (ii) aerosols in the vicinity of clouds. In both these circumstances, peak extinction coefficients of the order of 1000–1500 Mm−1 and AODs as large as 1–1.8 were encountered, but these features were either underestimated or not captured in the model predictions. Smoke injection heights derived from the Global Fire Assimilation System (GFAS) for the region are compatible with the general height of the aerosol layers.Airborne data were obtained using the
BAe-146-301 Atmospheric Research Aircraft (ARA) flown
by Directflight Ltd and managed by the Facility for Airborne
Atmospheric Measurements (FAAM), which is a joint entity
of the Natural Environment Research Council (NERC) and the
Met Office. SAMBBA was funded by the Met Office and NERC
(grant NE/J009822/1). Patrick Chazette and the Commissariat Ã
l’Energie Atomique et aux Energies Alternatives (CEA) are kindly
thanked for help fixing our lidar prior to SAMBB
(un)Doing standards in education with actor-network theory
Recent critiques have drawn important attention to the depoliticized consensus and empty promises embedded in network discourses of educational policy. While acceding this critique, this discussion argues that some forms of network analysis – specifically those adopting actor-network theory (ANT) approaches - actually offer useful theoretical resources for policy studies. Drawing from ANT-inspired studies of policy processes associated with educational standards, the article shows the ambivalences and contradictions as well as the possibilities that can be illuminated by ANT analysis of standards as networks. The discussion outlines the diverse network conceptions, considerations and sensibilities afforded by ANT approaches. Then it shows four phenomena that have been highlighted by ANT studies of educational standards: ordering (and rupturing) practice through ‘immutable mobiles’, local universality, tensions among networks of prescription and networks of negotiation, and different co-existing ontological forms of the same standards. The conclusion suggests starting points, drawing from these ANT-inspired network analyses, for examining policy processes associated with educational standards
Polarized point sources in the LOFAR Two-meter Sky Survey: A preliminary catalog
The polarization properties of radio sources at very low frequencies (h45m–15h30m right ascension, 45°–57° declination, 570 square degrees). We have produced a catalog of 92 polarized radio sources at 150 MHz at 4.′3 resolution and 1 mJy rms sensitivity, which is the largest catalog of polarized sources at such low frequencies. We estimate a lower limit to the polarized source surface density at 150 MHz, with our resolution and sensitivity, of 1 source per 6.2 square degrees. We find that our Faraday depth measurements are in agreement with previous measurements and have significantly smaller errors. Most of our sources show significant depolarization compared to 1.4 GHz, but there is a small population of sources with low depolarization indicating that their polarized emission is highly localized in Faraday depth. We predict that an extension of this work to the full LOTSS data would detect at least 3400 polarized sources using the same methods, and probably considerably more with improved data processing
- …