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Visualization of facet-dependent pseudo-photocatalytic behavior of TiO2 nanorods for water splitting using In situ liquid cell TEM
We report an investigation of the pseudo-photocatalytic behavior of rutile TiO2 nanorods for water splitting observed with liquid cell transmission electron microscopy (TEM). The electron beam serves as a âlightâ source to initiate the catalytic reaction and a âwater-in-saltâ aqueous solution is employed as the electrolyte. The observation reveals that bubbles are generated preferentially residing near the {110} facet of a rutile TiO2 nanorod under a low electron dose rate (9.3â18.6 e-/Ă
2·s). These bubbles are ascribed to hydrogen gas generated from the pseudo-photocatalytic water splitting. As the electron beam current density increases to 93 e-/Ă
2 ·s, bubbles are also found at the {001} and {111} facets as well as in the bulk liquid solution, demonstrating the dominant effects of water electrolysis by electron beam under higher dose rates. The facet-dependent pseudo-photocatalytic behavior of rutile TiO2 nanorods is further validated using density functional theory (DFT)calculation. Our work establishes a facile liquid cell TEM setup for the study of pseudo-photocatalytic water splitting and it may also be applied to investigation of other photo-activated phenomena occurring at the solid-liquid interfaces
The mineralogy of newly formed dust in active galactic nuclei
The tori around active galactic nuclei (AGN) are potential formation sites
for large amounts of dust, and they may help resolve the so-called dust budget
crisis at high redshift. We investigate the dust composition in 53 of the 87
Palomar Green (PG) quasars showing the 9.7 micron silicate feature in emission.
By simultaneously fitting the mid-infrared spectroscopic features and the
underlying continuum, we estimate the mass fraction in various amorphous and
crystalline dust species. We find that the dust consists predominantly of
alumina and amorphous silicates, with a small fraction in crystalline form. The
mean crystallinity is 8 +/- 6%, with more than half of the crystallinities
greater than 5%, well above the upper limit determined for the Galaxy. Higher
values of crystallinity are found for higher oxide fractions and for more
luminous sources.Comment: 24 pages, 9 figures, accepted for publication in Planetary and Space
Scienc
Injury Severity Score coding: Data analyst v. emerging m-health technology
Background. The cost of Abbreviated Injury Scale (AIS) coding has limited its utility in areas of the world with the highest incidence of trauma. We hypothesised that emerging mobile health (m-health) technology could offer a cost-effective alternative to the current goldstandard AIS mechanism in a high-volume trauma centre in South Africa.Methods. A prospectively collected sample of consecutive patients admitted following a traumatic injury that required an operation during a 1-month period was selected for the study. AISs and Injury Severity Scores (ISSs) were generated by clinician-entered data using an m-health application (ISS eTHR) as well as by a team of AIS coders at Vancouver General Hospital, Canada (ISS VGH). Rater agreements for ISSs were analysed using Bland-Altman plots with 95% limits of agreement (LoA) and kappa statistics of the ISSs grouped into ordinal categories. Reliability was analysed using a two-way mixed-model intraclass correlation coefficient (ICC). Calibration and discrimination of univariate logistic regression models built to predict in-hospital complications using ISSs coded by the two methods were also compared.Results. Fifty-seven patients were managed operatively during the study period. The mean age of the cohort was 27.2 years (range 14 - 62), and 96.3% were male. The mechanism of injury was penetrating in 93.4% of cases, of which 52.8% were gunshot injuries. The LoA fell within â8.6 - 9.4. The mean ISS difference was 0.4 (95% CI â0.8 - 1.6). The kappa statistic was 0.53. The ICC of the individual ISS was 0.88 (95% CI 0.81 - 0.93) and the categorical ISS was 0.81 (95% CI 0.68 - 0.87). Model performance to predict in-hospital complications using either the ISS eTHR or the ISS VGH was equivalent.Conclusions. ISSs calculated by the eTHR and gold-standard coding were comparable. Emerging m-health technology provides a costeffective alternative for injury severity scoring
Mass changes of southern and northern inylchek glacier, Central Tian Shan, kyrgyzstan, during âŒ1975 and 2007 derived from remote sensing data
Glacier melt is an essential source of freshwater for the arid regions surrounding the Tian Shan. However, the knowledge about glacier volume and mass changes over the last decades is limited. In the present study, glacier area, glacier dynamics and mass changes are investigated for the period âŒ1975-2007 for Southern Inylchek Glacier (SIG) and Northern Inylchek Glacier (NIG), the largest glacier system in Central Tian Shan separated by the regularly draining Lake Merzbacher. The area of NIG increased by 2.0 ± 0.1 km2 (âŒ1.3%) in the period âŒ1975-2007. In contrast, SIG has shrunk continuously in all investigated periods since âŒ1975. Velocities of SIG in the central part of the ablation region reached âŒ100-120 m a-1 in 2002/2003, which was slightly higher than the average velocity in 2010/2011. The central part of SIG flows mainly towards Lake Merzbacher rather than towards its terminus. The measured velocities at the distal part of the terminus downstream of Lake Merzbacher were below the uncertainty, indicating very low flow with even stagnant parts. Geodetic glacier mass balances have been calculated using multioral digital elevation models from KH-9 Hexagon (representing the year 1975), SRTM3 (1999), ALOS PRISM (2006) and SPOT-5 high-resolution geometrical (HRG) data (2007). In general, a continuous mass loss for both SIG and NIG could be observed between âŒ1975 and 2007. SIG lost mass at a rate of 0.43 ± 0.10 m w.e. a-1 and NIG at a rate of 0.25 ± 0.10 m w.e. ag-1 within the period âŒ1975-1999. For the period 1999-2007, the highest mass loss of 0.57 ± 0.46 m w.e. ag-1 was found for NIG, whilst SIG showed a potential moderate mass loss of 0.28 ± 0.46 m w.e. a-1. Both glaciers showed a small retreat during this period. Between âŒ1975 and 1999, we identified a thickening at the front of NIG with a maximum surface elevation increase of about 150 m as a consequence of a surge event. In contrast significant thinning (>0.5 m a-1) and comparatively high velocities close to the dam of Lake Merzbacher were observed for SIG, indicating that Lake Merzbacher enhances glacier mass loss.Publisher PDFPeer reviewe
Injury Severity Score coding: Data analyst v. emerging m-health technology
Background. The cost of Abbreviated Injury Scale (AIS) coding has limited its utility in areas of the world with the highest incidence of trauma. We hypothesised that emerging mobile health (m-health) technology could offer a cost-effective alternative to the current gold-standard AIS mechanism in a high-volume trauma centre in South Africa.Methods. A prospectively collected sample of consecutive patients admitted following a traumatic injury that required an operation during a 1-month period was selected for the study. AISs and Injury Severity Scores (ISSs) were generated by clinician-entered data using an m-health application (ISS eTHR) as well as by a team of AIS coders at Vancouver General Hospital, Canada (ISS VGH). Rater agreements for ISSs were analysed using Bland-Altman plots with 95% limits of agreement (LoA) and kappa statistics of the ISSs grouped into ordinal categories. Reliability was analysed using a two-way mixed-model intraclass correlation coefficient (ICC). Calibration and discrimination of univariate logistic regression models built to predict in-hospital complications using ISSs coded by the two methods were also compared.Results. Fifty-seven patients were managed operatively during the study period. The mean age of the cohort was 27.2 years (range 14 - 62), and 96.3% were male. The mechanism of injury was penetrating in 93.4% of cases, of which 52.8% were gunshot injuries. The LoA fell within â8.6 - 9.4. The mean ISS difference was 0.4 (95% CI â0.8 - 1.6). The kappa statistic was 0.53. The ICC of the individual ISS was 0.88 (95% CI 0.81 - 0.93) and the categorical ISS was 0.81 (95% CI 0.68 - 0.87). Model performance to predict in-hospital complications using either the ISS eTHR or the ISS VGH was equivalent.Conclusions. ISSs calculated by the eTHR and gold-standard coding were comparable. Emerging m-health technology provides a cost-effective alternative for injury severity scoring.
Broad-line region geometry from multiple emission lines in a single-epoch spectrum
The broad-line region (BLR) of active galactic nuclei (AGNs) traces gas close
to the central supermassive black hole (BH). Recent reverberation mapping (RM)
and interferometric spectro-astrometry data have enabled detailed
investigations of the BLR structure and dynamics, as well as estimates of the
BH mass. These exciting developments motivate comparative investigations of BLR
structures using different broad emission lines. In this work, we have
developed a method to simultaneously model multiple broad lines of the BLR from
a single-epoch spectrum. We apply this method to the five strongest broad
emission lines (H, H, H, Pa, and He
5876) in the UV-to-NIR spectrum of NGC 3783, a nearby Type I AGN
which has been well studied by RM and interferometric observations. Fixing the
BH mass to the published value, we fit these line profiles simultaneously to
constrain the BLR structure. We find that the differences between line profiles
can be explained almost entirely as being due to different radial distributions
of the line emission. We find that using multiple lines in this way also
enables one to measure some important physical parameters, such as the
inclination angle and virial factor of the BLR. The ratios of the derived BLR
time lags are consistent with the expectation of theoretical model calculations
and RM measurements.Comment: 16 pages, 9 figures, 4 tables, accepted for publication in A&
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