519 research outputs found
Incorporation by coordination and release of the iron chelator drug deferiprone from zinc-based metal–organic frameworks
A series of new zinc-based metal–organic framework materials has been prepared in which deferiprone is incorporated as a chelating ligand on infinite or tri-zinc secondary building units following deprotonation. Deferiprone is immediately released from the MOFs on treatments with 1 N hydrochloric acid or buffer, but slow release is observed in ethanoic acid
Observations of Buried Lake Drainage on the Antarctic Ice Sheet.
Between 1992 and 2017, the Antarctic Ice Sheet (AIS) lost ice equivalent to 7.6 ± 3.9 mm of sea level rise. AIS mass loss is mitigated by ice shelves that provide a buttress by regulating ice flow from tributary glaciers. However, ice-shelf stability is threatened by meltwater ponding, which may initiate, or reactivate preexisting, fractures, currently poorly understood processes. Here, through ground penetrating radar (GPR) analysis over a buried lake in the grounding zone of an East Antarctic ice shelf, we present the first field observations of a lake drainage event in Antarctica via vertical fractures. Concurrent with the lake drainage event, we observe a decrease in surface elevation and an increase in Sentinel-1 backscatter. Finally, we suggest that fractures that are initiated or reactivated by lake drainage events in a grounding zone will propagate with ice flow onto the ice shelf itself, where they may have implications for its stability
The spin-orbit alignment of the transiting exoplanet WASP-3b from Rossiter-McLaughlin observations
We present an observation of the Rossiter-McLaughlin effect for the planetary
system WASP-3. Radial velocity measurements were made during transit using the
SOPHIE spectrograph at the 1.93m telescope at Haute-Provence Observatory. The
shape of the effect shows that the sky-projected angle between the stellar
rotation axis and planetary orbital axis (lambda) is small and consistent with
zero within 2 sigma; lambda = 15 +10/-9 deg. WASP-3b joins the ~two-thirds of
planets with measured spin-orbit angles that are well aligned and are thought
to have undergone a dynamically-gentle migration process such as planet-disc
interactions. We find a systematic effect which leads to an anomalously high
determination of the projected stellar rotational velocity (vsini = 19.6
+2.2/-2.1 km/s) compared to the value found from spectroscopic line broadening
(vsini = 13.4 +/- 1.5 km/s). This is thought to be caused by a discrepancy in
the assumptions made in the extraction and modelling of the data. Using a model
developed by Hirano et al. (2009) designed to address this issue, we find vsini
to be consistent with the value obtained from spectroscopic broadening
measurements (vsini = 15.7 +1.4/-1.3 km/s).Comment: 7 pages, 3 figures, published in MNRAS 405 (2010) 1867-1872. Update
includes discussion on differential rotaation and correction of typo
The spin-orbit angles of the transiting exoplanets WASP-1b, WASP-24b, WASP-38b and HAT-P-8b from Rossiter-McLaughlin observations
We present observations of the Rossiter-McLaughlin effect for the transiting
exoplanet systems WASP-1, WASP-24, WASP-38 and HAT-P-8, and deduce the
orientations of the planetary orbits with respect to the host stars' rotation
axes. The planets WASP-24b, WASP-38b and HAT-P-8b appear to move in prograde
orbits and be well aligned, having sky-projected spin orbit angles consistent
with zero: {\lambda} = -4.7 \pm 4.0{\deg}, {\lambda} = 15 + 33{\deg}/-43{\deg}
and {\lambda} = -9.7 +9.0{\deg}/-7.7{\deg}, respectively. The host stars have
Teff < 6250 K and conform with the trend of cooler stars having low
obliquities. WASP-38b is a massive planet on a moderately long period,
eccentric orbit so may be expected to have a misaligned orbit given the high
obliquities measured in similar systems. However, we find no evidence for a
large spin-orbit angle. By contrast, WASP-1b joins the growing number of
misaligned systems and has an almost polar orbit, {\lambda} = -79
+4.5{\deg}/-4.3{\deg}. It is neither very massive, eccentric nor orbiting a hot
host star, and therefore does not share the properties of many other misaligned
systems.Comment: Submitted to MNRAS, 13 pages, 8 tables, 6 figures. Includes revised
parameter values for WASP-38 and HAT-P-
Randomised trial of indwelling pleural catheters for refractory transudative pleural effusions
Objective: Refractory symptomatic transudative pleural effusions are an indication for pleural drainage. There has been supportive observational evidence for the use of indwelling pleural catheters (IPCs) for transudative effusions, but no randomised trials. We aimed to investigate the effect of IPCs on breathlessness in patients with transudative pleural effusions when compared with standard care. /
Methods: A multicentre randomised controlled trial, in which patients with transudative pleural effusions were randomly assigned to either an IPC (intervention) or therapeutic thoracentesis (TT; standard care). The primary outcome was mean daily breathlessness score over 12 weeks from randomisation. /
Results: 220 patients were screened from April 2015 to August 2019 across 13 centres, with 33 randomised to intervention (IPC) and 35 to standard care (TT). Underlying aetiology was heart failure in 46 patients, liver failure in 16 and renal failure in six. In primary outcome analysis, the mean±sd breathlessness score over the 12-week study period was 39.7±29.4 mm in the IPC group and 45.0±26.1 mm in the TT group (p=0.67). Secondary outcomes analysis demonstrated that mean±sd drainage was 17 412±17 936 mL and 2901±2416 mL in the IPC and TT groups, respectively. A greater proportion of patients had at least one adverse event in the IPC group (p=0.04). /
Conclusion: We found no significant difference in breathlessness over 12 weeks between IPCs or TT. TT is associated with fewer complications and IPCs reduced the number of invasive pleural procedures required. Patient preference and circumstances should be considered in selecting the intervention in this cohort
The spin-orbit angles of the transiting exoplanets WASP-1b, WASP-24b, WASP-38b and HAT-P-8b from Rossiter-McLaughlin observations
We present observations of the Rossiter-McLaughlin effect for the transiting exoplanets WASP-1b, WASP-24b, WASP-38b and HAT-P-8b, and deduce the orientations of the planetary orbits with respect to the host stars' rotation axes. The planets WASP-24b, WASP-38b and HAT-P-8b appear to move in prograde orbits and be well aligned, having sky-projected spin-orbit angles consistent with zero: λ=−4°.7 ± 4°.0, 15°+33−43 and , respectively. The host stars have Teff < 6250 K and conform with the trend of cooler stars having low obliquities. WASP-38b is a massive planet on a moderately long period, eccentric orbit so may be expected to have a misaligned orbit given the high obliquities measured in similar systems. However, we find no evidence for a large spin-orbit angle. By contrast, WASP-1b joins the growing number of misaligned systems and has an almost polar orbit, λ=. It is neither very massive, eccentric nor orbiting a hot host star, and therefore does not share the properties of many other misaligned system
The unusual NIV]-emitter galaxy GDS J033218.92-275302.7: star formation or AGN-driven winds from a massive galaxy at z=5.56
Aims: We investigate the nature of the source GDS J033218.92-275302.7at
redshift ~ 5.56. Methods: The SED of the source is well sampled by 16 bands
photometry, from UV-optical, near infrared and mid-infrared (MID-IR).The
detection of signal in the MID-IR Spitzer/IRAC bands 5.8, 8.0 um -- where the
nebular emission contribution is less effective -- suggests the presence of a
Balmer break, signature of an underlying stellar population formed at earlier
epochs. The optical spectrum shows a clear Lya emission line together with
semi-forbidden NIV] 1483.3-1486.5 also in emission. Results: From the SED
fitting and the Lya modelling it turns out that the source seems to have an
evolved component with stellar mass of ~5 x10^(10) Msolar and age ~ 0.4 Gyrs,
and a young component with an age of ~ 0.01 Gyrs and SFR in the range of 30-200
Msolar yr^(-1). The limits on the effective radius derived from the ACS/z850
and VLT/Ks bands indicate that this galaxy is denser than the local ones with
similar mass. A relatively high nebular gas column density is favored from the
Lya line modelling (NHI>=10^(21) cm^(-2)). A vigorous outflow (~ 450 km/s) has
been measured from the optical spectrum,consistent with the Lya modelling. From
ACS observations it turns out that the region emitting Lya photons is spatially
compact and of the same order of the effective radius estimated at the ~1400A
rest-frame wavelength, whose emission is dominated by the stellar continuum
and/or AGN. The gas is blown out from the central region,but given the mass of
the galaxy it is uncertain whether it will pollute the IGM to large distances.
We argue that a burst of star formation in a dense gas environment is active
(possibly containing hot and massive stars and/or a low luminosity AGN),
superimposed to an already formed fraction of stellar mass (abridged).Comment: 13 pages, 9 figures (published on A&A). Here replaced with a typo
fixed in the footnote of Sect. 4.2 and with four updated references. Results
unchange
Community Risk Factors for Ocular Chlamydia Infection in Niger: Pre-Treatment Results from a Cluster-Randomized Trachoma Trial
Trachoma is one of the most important neglected tropical diseases because it is the leading cause of blindness from an infection in the world. There are about 1.3 million persons blind from the disease and many more at risk of blindness in the future. It is caused by the common bacterium Chlamydia trachomatis and can be treated with mass drug administrations (MDA) of azithromycin. We have begun a clinical trial in Niger, a country with limited resources in Africa, to determine the best treatment strategy. Our study from May to July 2010, which began before MDA's were given, showed that 26% of children aged 0–5 years were infected with the disease. In these children, we found that discharge from the nose, presence of flies on the face, and the number of years of education completed by the head of the household were risk factors for infection in 48 different communities. We hope to use this information about risk factors of infection to help guide future studies for trachoma and also to help with the WHO goal of eliminating the disease worldwide by the year 2020
Alinhamento interpessoal, representacional e morfossintático na Gramática Discursivo-Funcional
Este artigo se debruça sobre o mapeamento entre os NÃveis Interpessoal, Representacional e Morfossintático da gramática, o chamado alinhamento, segundo o arcabouço da Gramática Discursivo-Funcional (GDF). Propõe uma tipologia das lÃnguas baseada no que a sua organização morfossintática codifica: distinções pragmáticas (p.ex. em Tagalo), distinções semânticas (p.ex. em Achém), ou distinções inerentes à morfossintaxe (p.ex. em Inglês, Basco ou a lÃngua Kham). A inclusão tanto do Sujeito como do Objeto e de lÃnguas tanto acusativas como ergativas no tratamento do alinhamento morfossintático permitiu-nos abranger tipos tipologicamente mais variáveis e demonstrar o potencial da GDF para a análise contrastiva das lÃnguas.<br>Within the framework of Functional Discourse Grammar (FDG), alignment concerns the relations between the Interpersonal, Representational and Morphosyntactic Levels of grammar. This article proposes a typology of languages based upon what we find to be encoded in their morphosyntactic organization: pragmatic distinctions (as in Tagalog), semantic distinctions (as in Acheh), or distinctions inherent to the morphosyntax (as in English, Basque and Kham). By including both subject and object, and both accusative and ergative languages in our treatment of morphosyntactic alignment, we provide a better coverage of typological variation and show the potential of FDG for cross-linguistic analysis
- …