39 research outputs found
Mealtime Behaviour and Parent-Child Interaction: A Comparison of Children with Cystic Fibrosis, Children with Feeding Problems, and Nonclinic Controls
Examined the role of family interaction factors in dietary compliance problems reported by parents of children with cystic fibrosis (CF). The family mealtime interactions of children with CF, children with feeding problems and nonclinic controls were observed, and parents monitored children's eating behavior at home. Parents of children with CF reported more concern about feeding problems and recorded more disruptive mealtime behavior than parents of nonclinic children. Observational data showed children with CF to display overall rates of disruptive mealtime behavior not significantly different from either comparison group. Mothers of children with CF were observed to engage in higher rates of aversive interaction with their child than did mothers of nonclinic controls. Fathers of children with CF reported lower marital satisfaction than fathers of controls. Both mothers and fathers of children with CF reported lower parenting self-efficacy than non-CF families. Clinical implications are discussed
On the source of the late-time infrared luminosity of SN 1998S and other type II supernovae
We present late-time near-infrared (NIR) and optical observations of the type
IIn SN 1998S. The NIR photometry spans 333-1242 days after explosion, while the
NIR and optical spectra cover 333-1191 days and 305-1093 days respectively. The
NIR photometry extends to the M'-band (4.7 mu), making SN 1998S only the second
ever supernova for which such a long IR wavelength has been detected. The shape
and evolution of the H alpha and HeI 1.083 mu line profiles indicate a powerful
interaction with a progenitor wind, as well as providing evidence of dust
condensation within the ejecta. The latest optical spectrum suggests that the
wind had been flowing for at least 430 years. The intensity and rise of the HK
continuum towards longer wavelengths together with the relatively bright L' and
M' magnitudes shows that the NIR emission was due to hot dust newly-formed in
supernovae may provide the ejecta and/or pre-existing dust in the progenitor
circumstellar medium (CSM). [ABRIDGED] Possible origins for the NIR emission
are considered. Significant radioactive heating of ejecta dust is ruled out, as
is shock/X-ray-precursor heating of CSM dust. More plausible sources are (a) an
IR-echo from CSM dust driven by the UV/optical peak luminosity, and (b)
emission from newly-condensed dust which formed within a cool, dense shell
produced by the ejecta shock/CSM interaction. We argue that the evidence
favours the condensing dust hypothesis, although an IR-echo is not ruled out.
Within the condensing-dust scenario, the IR luminosity indicates the presence
of at least 0.001 solar masses of dust in the ejecta, and probably considerably
more. Finally, we show that the late-time intrinsic (K-L') evolution of type II
supernovae may provide a useful tool for determining the presence or absence of
a massive CSM around their progenitor stars.Comment: 23 pages, 15 figures, to be published in MNRA
The Westerbork HI Survey of spiral and irregular galaxies III: HI observations of early-type disk galaxies
We present HI observations of 68 early-type disk galaxies from the WHISP
survey. They have morphological types between S0 and Sab and absolute B-band
magnitudes between -14 and -22. These galaxies form the massive, high
surface-brightness extreme of the disk galaxy population, few of which have
been imaged in HI before.
The HI properties of the galaxies in our sample span a large range; the
average values of M_HI/L_B and D_HI/D_25 are comparable to the ones found in
later-type spirals, but the dispersions around the mean are larger. No
significant differences are found between the S0/S0a and the Sa/Sab galaxies.
Our early-type disk galaxies follow the same HI mass-diameter relation as
later-type spiral galaxies, but their effective HI surface densities are
slightly lower than those found in later-type systems.
In some galaxies, distinct rings of HI emission coincide with regions of
enhanced star formation, even though the average gas densities are far below
the threshold of star formation derived by Kennicutt (1989). Apparently,
additional mechanisms, as yet unknown, regulate star formation at low surface
densities.
Many of the galaxies in our sample have lopsided gas morphologies; in most
cases this can be linked to recent or ongoing interactions or merger events.
Asymmetries are rare in quiescent galaxies. Kinematic lopsidedness is rare,
both in interacting and isolated systems.
In the appendix, we present an atlas of the HI observations: for all galaxies
we show HI surface density maps, global profiles, velocity fields and radial
surface density profiles.Comment: 24 pages, 11 figures. Accepted for publication in A&A. A version with
the full atlas can be downloaded from
http://www.astro.rug.nl/~edo/WHISPIII.ps.gz (gzipped postscript, 9.3Mb
Abundance stratification in Type Ia supernovae - IV. The luminous, peculiar SN 1991T
The abundance distribution of the elements in the ejecta of the peculiar, luminous Type Ia supernova (SN Ia) 1991T is obtained modelling spectra from before maximum light until a year after the explosion, with the method of âAbundance Tomographyâ. SN 1991T is different from other slowly declining SNe Ia (e.g. SN 1999ee) in having a weaker Si II 6355 line and strong features of iron group elements before maximum. The distance to the SN is investigated along with the abundances and the density profile. The ionization transition that happens around maximum sets a strict upper limit on the luminosity. Both W7 and the WDD3 delayed detonation models are tested. WDD3 is found to provide marginally better fits. In this model the core of the ejecta is dominated by stable Fe with a mass of about 0.15âMâ, as in most SNe Ia. The layer above is mainly 56Ni up to v âź 10â000âkmâsâ1 (â0.78âMâ). A significant amount of 56Ni (âź3 per cent) is located in the outer layers. A narrow layer between 10 000âkmâsâ1 and âź12â000âkmâsâ1 is dominated by intermediate-mass elements (IME), âź0.18âMâ. This is small for a SN Ia. The high luminosity and the consequently high ionization, and the high 56Ni abundance at high velocities, explain the peculiar early-time spectra of SN 1991T. The outer part is mainly of oxygen, âź0.3âMâ. Carbon lines are never detected, yielding an upper limit of 0.01âMâ for C. The abundances obtained with the W7 density model are qualitatively similar to those of the WDD3 model. Different elements are stratified with moderate mixing, resembling a delayed detonation
Galaxy morphology, kinematics and clustering in a hydrodynamic simulation of a LambdaCDM universe
We explore galaxy properties and their link with environment and clustering
using a population of ~1000 galaxies formed in a high resolution hydrodynamic
simulation of the Lambda CDM cosmology. At the redshift we concentrate on, z=1,
the spatial resolution is 1.4 proper kpc/h and Milky-way sized disk galaxies
contain ~10^5 particles within their virial radii. We include supermassive
black hole accretion and feedback as well as a multiphase model for star
formation. We find that a number of familiar qualitative relationships hold
approximately between galaxy properties, for example, galaxies lie between two
broad extremes of type, where ``late'' types tend to be smaller in size, have
lower circular velocities, younger stars, higher star formation rates, larger
disk to bulge ratios and lower Sersic indices than ``early types''. As in
previous studies the stellar component of disk galaxies is not as rotationally
supported as in observations. Bulges contain too much of the stellar mass,
although disks do have scale lengths compatible with observations. The addition
of black hole physics to the simulations does not appear to have an impact on
the angular momentum results, nor do we find that it is affected in an
identical simulation with significantly lower mass resolution. Despite this, we
can profitably use the rank order of either disk to total ratio, Sersic index,
or galaxy age to separate galaxies into morphological classes and examine the
density-morphology relation and morphology dependence of clustering. We find
that while at redshift z=0, the well known preponderance of early types in
dense environments is seen, at z=1 the density-morphology relation becomes
flatter and late type galaxies are even seen to have a higher clustering
amplitude than early types (abridged).Comment: 25 pages, 15 figures, submitted to MNRA
Optical and IR observations of SN 2002dj: some possible common properties of fast expanding SNe Ia
As part of the European Supernova Collaboration we obtained extensive
photometry and spectroscopy of the type Ia SN 2002dj covering epochs from 11
days before to nearly two years after maximum. Detailed optical and
near-infrared observations show that this object belongs to the class of the
high-velocity gradient events as indicated by Si, S and Ca lines. The light
curve shape and velocity evolution of SN 2002dj appear to be nearly identical
to SN 2002bo. The only significant difference is observed in the optical to
near-IR colours and a reduced spectral emission beyond 6500 A. For
high-velocity gradient Type Ia supernovae, we tentatively identify a faster
rise to maximum, a more pronounced inflection in the V and R light curves after
maximum and a brighter, slower declining late-time B light curve as common
photometric properties of this class of objects. They also seem to be
characterized by a different colour and colour evolution with respect to
``normal'' SNe Ia. The usual light curve shape parameters do not distinguish
these events. Stronger, more blueshifted absorption features of
intermediate-mass elements and lower temperatures are the most prominent
spectroscopic features of Type Ia supernovae displaying high velocity
gradients. It appears that these events burn more intermediate-mass elements in
the outer layers. Possible connections to the metallicity of the progenitor
star are explored.Comment: Equations A4, A5 and A7 in the appendix section have been corrected.
Part of text in the appendix has been remove
Studies of jet mass in dijet and W/Z plus jet events
This is the pre-print version of the final published paper that is available from the link below.Invariant mass spectra for jets reconstructed using the anti-kT and Cambridge-Aachen algorithms are studied for different jet âgroomingâ techniques in data corresponding to an integrated luminosity of 5 fb-1, recorded with the CMS detector in proton-proton collisions at the LHC at a center-of-mass energy of 7TeV. Leading-order QCD predictions for inclusive dijet and W/Z+jet production combined with parton-shower Monte Carlo models are found to agree overall with the data, and the agreement improves with the implementation of jet grooming methods used to distinguish merged jets of large transverse momentum from softer QCD gluon radiation
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Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.
Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (nâ=â143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (nâ=â152), or no hydrocortisone (nâ=â108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (nâ=â137), shock-dependent (nâ=â146), and no (nâ=â101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707