1,372 research outputs found
Sensitive Coverage Saves Lives: Improving media portrayal of suicidal behaviour
The report outlines the results of consultations with journalists, suicide prevention agencies and mental health groups conducted by the journalism ethics charity MediaWise. It makes recommendations for action by media organisations and suicide prevention agencies
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Realization and efficiency evaluation of a micro-photocatalytic cell prototype for real-time blood oxygenation
This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.A novel approach to blood oxygenation is presented. Microfluidic channels molded out of PDMS (using standard soft lithography techniques) work as photocatalytic cells, where the coupling of anatase titanium dioxide (TiO2) thin films and platinum electrodes, allow an electrically assisted photocatalytic reaction to produce dissolved oxygen gas from the water content of the flowing blood. The thin films were deposited onto quartz glass substrates at room temperature (300K) using reactive RF sputtering with a Ti metal target. The results of the current study, as a proof of concept, have shown that the device can generate oxygen at a rate of 4.06×10-3 mM O2/(cm2 min) and oxygenate venous blood to the oxygen saturation level of arterial blood
Neutral gas in Lyman-alpha emitting galaxies Haro 11 and ESO 338-IG04 measured through sodium absorption
Context. The Lyman alpha emission line of galaxies is an important tool for
finding galaxies at high redshift, and thus probe the structure of the early
universe. However, the resonance nature of the line and its sensitivity to dust
and neutral gas is still not fully understood.
Aims. We present measurements of the velocity, covering fraction and optical
depth of neutral gas in front of two well known local blue compact galaxies
that show Lyman alpha in emission: ESO 338-IG 04 and Haro 11. We thus test
observationally the hypothesis that Lyman alpha can escape through neutral gas
by being Doppler shifted out of resonance.
Methods. We present integral field spectroscopy from the GIRAFFE/Argus
spectrograph at VLT/FLAMES in Paranal, Chile. The excellent wavelength
resolution allows us to accurately measure the velocity of the ionized and
neutral gas through the H-alpha emission and Na D absorption, which traces the
ionized medium and cold interstellar gas, respectively. We also present
independent measurements with the VLT/X-shooter spectrograph which confirm our
results.
Results. For ESO 338-IG04, we measure no significant shift of neutral gas.
The best fit velocity is -15 (16) km/s. For Haro 11, we see an outflow from
knot B at 44 (13) km/s and infalling gas towards knot C with 32 (12) km/s.
Based on the relative strength of the Na D absorption lines, we estimate low
covering fractions of neutral gas (down to 10%) in all three cases.
Conclusions. The Na D absorption likely occurs in dense clumps with higher
column densities than where the bulk of the Ly-alpha scattering takes place.
Still, we find no strong correlation between outflowing neutral gas and a high
Lyman alpha escape fraction. The Lyman alpha photons from these two galaxies
are therefore likely escaping due to a low column density and/or covering
fraction.Comment: 9 pages, 3 figure
Data-driven prediction of vortex-induced vibration response of marine risers subjected to three-dimensional current
Slender marine structures such as deep-water marine risers are subjected to
currents and will normally experience Vortex Induced Vibrations (VIV), which
can cause fast accumulation of fatigue damage. The ocean current is often
three-dimensional (3D), i.e., the direction and magnitude of the current vary
throughout the water column. Today, semi-empirical tools are used by the
industry to predict VIV induced fatigue on risers. The load model and
hydrodynamic parameters in present VIV prediction tools are developed based on
two-dimensional (2D) flow conditions, as it is challenging to consider the
effect of 3D flow along the risers. Accordingly, the current profiles must be
purposely made 2D during the design process, which leads to significant
uncertainty in the prediction results. Further, due to the limitations in the
laboratory, VIV model tests are mostly carried out under 2D flow conditions and
thus little experimental data exist to document VIV response of riser subjected
to varying directions of the current. However, a few experiments have been
conducted with 3D current. We have used results from one of these experiments
to investigate how well 1) traditional and 2) an alternative method based on a
data driven prediction can describe VIV in 3D currents. Data driven modelling
is particularly suited for complicated problems with many parameters and
non-linear relationships. We have applied a data clustering algorithm to the
experimental 3D flow data in order to identify measurable parameters that can
influence responses. The riser responses are grouped based on their statistical
characteristics, which relate to the direction of the flow. Furthermore we fit
a random forest regression model to the measured VIV response and compare its
performance with the predictions of existing VIV prediction tools (VIVANA-FD).Comment: 12 pages, presented at Norwegian AI Society Symposium 2019, accepted
for publication in Springer Conference Proceeding
The Sunburst Arc: Direct Lyman {\alpha} escape observed in the brightest known lensed galaxy
We present rest-frame ultraviolet and optical spectroscopy of the brightest
lensed galaxy yet discovered, at redshift z = 2.4. This source reveals a
characteristic, triple-peaked Lyman {\alpha} profile which has been predicted
by various theoretical works but to our knowledge has not been unambiguously
observed previously. The feature is well fit by a superposition of two
components: a double-peak profile emerging from substantial radiative transfer,
and a narrow, central component resulting from directly escaping Lyman {\alpha}
photons; but is poorly fit by either component alone. We demonstrate that the
feature is unlikely to contain contamination from nearby sources, and that the
central peak is unaffected by radiative transfer effects apart from very slight
absorption. The feature is detected at signal-to-noise ratios exceeding 80 per
pixel at line center, and bears strong resemblance to synthetic profiles
predicted by numerical models.Comment: Accepted for publication in Astronomy & Astrophysics. 4 pages, 5
figure
Dyeability of corona-treated fabrics
In this study, corona technology is applied in the wet processing of cotton fabrics. The properties of cotton, such as hydrophilicity, ionisation and mechanical properties, are evaluated and compared with previous results of cuticle oxidation and morphological changes. The results of dyeings of coronatreated materials under different conditions are compared with those of raw, bleached and desized cotton. The dyeings are carried out with three different commercial direct dyes. The classical method for the processing of cotton materials and the corona discharge method are discussed and compared in order to analyse the advantages of this innovative process
Gravitational lensing reveals ionizing ultraviolet photons escaping from a distant galaxy
During the epoch of reionisation, neutral gas in the early Universe was
ionized by hard ultraviolet radiation emitted by young stars in the first
galaxies. To do so, ionizing ultraviolet photons must escape from the host
galaxy. We present Hubble Space Telescope observations of the gravitationally
lensed galaxy PSZ1-ARC G311.6602-18.4624, revealing bright, multiply-imaged
ionizing photon escape from a compact star-forming region through a narrow
channel in an optically thick gas. The gravitational lensing magnification
shows how ionizing photons escape this galaxy, contributing to the
re-ionization of the Universe. The multiple sight lines to the source probe
absorption by intergalactic neutral hydrogen on scales of no more than a few
hundred, perhaps even less than ten, parsec.Comment: 17 pages, 9 figures. Published in Scienc
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