95 research outputs found
Accretion-related properties of Herbig Ae/Be stars. Comparison with T Tauris
We look for trends relating the mass accretion rate (Macc) and the stellar
ages (t), spectral energy distributions (SEDs), and disk masses (Mdisk) for a
sample of 38 HAeBe stars, comparing them to analogous correlations found for
classical T Tauri stars. Our goal is to shed light on the timescale and
physical processes that drive evolution of intermediate-mass pre-main sequence
objects.
Macc shows a dissipation timescale \tau = 1.3^{+1.0}_{-0.5} Myr from an
exponential law fit, while a power law yields Macc(t) \propto t^{-\eta}, with
\eta = 1.8^{+1.4}_{-0.7}. This result is based on our whole HAeBe sample (1-6
Msun), but the accretion rate decline most probably depends on smaller stellar
mass bins. The near-IR excess is higher and starts at shorter wavelengths (J
and H bands) for the strongest accretors. Active and passive disks are roughly
divided by 2 x 10^{-7} Msun/yr. The mid-IR excess and the SED shape from the
Meeus et al. classification are not correlated with Macc. We find Macc \propto
Mdisk^{1.1 +- 0.3}. Most stars in our sample with signs of inner dust
dissipation typically show accretion rates ten times lower and disk masses
three times smaller than the remaining objects.
The trends relating Macc with the near-IR excess and Mdisk extend those for T
Tauri stars, and are consistent with viscous disk models. The differences in
the inner gas dissipation timescale, and the relative position of the stars
with signs of inner dust clearing in the Macc-Mdisk plane, could be suggesting
a slightly faster evolution, and that a different process - such as
photoevaporation - plays a more relevant role in dissipating disks in the HAeBe
regime compared to T Tauri stars. Our conclusions must consider the mismatch
between the disk mass estimates from mm fluxes and the disk mass estimates from
accretion, which we also find in HAeBe stars.Comment: 11 pages, 7 figures, 1 appendix. Accepted in A&
Does Pregnancy Alter Life Course Lipid Trajectories?:Evidence from the HUNT Study in Norway
We examined the association between pregnancy and life-course lipid trajectories. Linked data from the Nord-Trøndelag Health Study and the Medical Birth Registry of Norway yielded 19,987 parous and 1,625 nulliparous women. Using mixed-effects spline models, we estimated differences in nonfasting lipid levels from before to after first birth in parous women and between parous and nulliparous women. HDL cholesterol (HDL-C) dropped by −4.2 mg/dl (95% CI: −5.0, −3.3) from before to after first birth in adjusted models, a 7% change, and the total cholesterol (TC) to HDL-C ratio increased by 0.18 (95% CI: 0.11, 0.25), with no change in non-HDL-C or triglycerides. Changes in HDL-C and the TC/HDL-C ratio associated with pregnancy persisted for decades, leading to altered life-course lipid trajectories. For example, parous women had a lower HDL-C than nulliparous women at the age of 50 years (−1.4 mg/dl; 95% CI: −2.3, −0.4). Adverse changes in lipids were greatest after first birth, with small changes after subsequent births, and were larger in women who did not breastfeed. Findings suggest that pregnancy is associated with long-lasting adverse changes in HDL-C, potentially setting parous women on a more atherogenic trajectory than prior to pregnancy
Live birth rates and perinatal outcomes when all embryos are frozen compared with conventional fresh and frozen embryo transfer: a cohort study of 337,148 in vitro fertilisation cycles
BACKGROUND: It is not known whether segmentation of an in vitro fertilisation (IVF) cycle, with freezing of all embryos prior to transfer, increases the chance of a live birth after all embryos are transferred. METHODS: In a prospective study of UK Human Fertilisation and Embryology Authority data, we investigated the impact of segmentation, compared with initial fresh embryo followed by frozen embryo transfers, on live birth rate and perinatal outcomes. We used generalised linear models to assess the effect of segmentation in the whole cohort, with additional analyses within women who had experienced both segmentation and non-segmentation. We compared rates of live birth, low birthweight (LB
Cardiac rehabilitation adapted to transient ischaemic attack and stroke (CRAFTS): a randomised controlled trial
<p>Abstract</p> <p>Background</p> <p>Coronary Heart Disease and Cerebrovascular Disease share many predisposing, modifiable risk factors (hypertension, abnormal blood lipids and lipoproteins, cigarette smoking, physical inactivity, obesity and diabetes mellitus). Lifestyle interventions and pharmacological therapy are recognised as the cornerstones of secondary prevention. Cochrane review has proven the benefits of programmes incorporating exercise and lifestyle counselling in the cardiac disease population. A Cochrane review highlighted as priority, the need to establish feasibility and efficacy of exercise based interventions for Cerebrovascular Disease.</p> <p>Methods</p> <p>A single blind randomised controlled trial is proposed to examine a primary care cardiac rehabilitation programme for adults post transient ischemic attack (TIA) and stroke in effecting a positive change in the primary outcome measures of cardiac risk scores derived from Blood Pressure, lipid profile, smoking and diabetic status and lifestyle factors of habitual smoking, exercise and healthy eating participation. Secondary outcomes of interest include health related quality of life as measured by the Hospital Anxiety and Depression Scale, the Stroke Specific Quality of Life scale and WONCA COOP Functional Health Status charts and cardiovascular fitness as measured by a sub-maximal fitness test.</p> <p>A total of 144 patients, over 18 years of age with confirmed diagnosis of ischaemic stroke or TIA, will be recruited from Dublin community stroke services and two tertiary T.I.A clinics. Exclusion criteria will include oxygen dependence, unstable cardiac conditions, uncontrolled diabetes, major medical conditions, claudication, febrile illness, pregnancy or cognitive impairment. Participants will be block-statified, randomly allocated to one of two groups using a pre-prepared computer generated randomisation schedule. Both groups will receive a two hour education class on risk reduction post stroke. The intervention group will receive a 10 week programme of supervised aerobic exercises (twice weekly) and individually tailored brief intervention lifestyle counselling. Both groups will be tested on week one and week ten of the programme. Follow-up at 1 year will assess longer term benefits. Analysis will test for significant changes in the key variables indicated.</p> <p>Discussion</p> <p>Application of the Cardiac Rehabilitation paradigm to patients with ischaemic stroke or TIA has not been explored despite the obvious overlap in aetiology. It is hoped the anticipated improvement in vascular risk factors and fitness resulting from such a programme will enhance health and social gain in this population.</p> <p>Trial Registration</p> <p>Current Controlled Trials ISCTRN90272638.</p
Long COVID burden and risk factors in 10 UK longitudinal studies and electronic health records
Risk and prognostic significance of tuberculosis in patients from The TREAT Asia HIV Observational Database
10.1186/1471-2334-9-46BMC Infectious Diseases94
A 'Rosetta Stone' for protoplanetary disks:the synergy of multi-wavelength observations
The recent progress in instrumentation and telescope development has brought
us different ways to observe protoplanetary disks, including interferometers,
space missions, adaptive optics, polarimetry, and time- and spectrally-resolved
data. While the new facilities have changed the way we can tackle the existing
open problems in disk structure and evolution, there is a substantial lack of
interconnection between different observing techniques and their user
communities. Here, we explore the complementarity of some of the
state-of-the-art observing techniques, and how they can be brought together in
a collective effort to understand how disks evolve and disperse at the time of
planet formation.
This paper was born at the "Protoplanetary Discussions" meeting in Edinburgh,
2016. Its goal is to clarify where multi-wavelength observations of disks
converge in unveiling disk structure and evolution, and where they diverge and
challenge our current understanding. We discuss caveats that should be
considered when linking results from different observations, or when drawing
conclusions based on limited datasets (in terms of wavelength or sample). We
focus on disk properties that are currently being revolutionized by
multi-wavelength observations. Specifically: the inner disk radius, holes and
gaps and their link to large-scale disk structures, the disk mass, and the
accretion rate. We discuss how the links between them, as well as the apparent
contradictions, can help us to disentangle the disk physics and to learn about
disk evolution.Comment: Accepted for publication in PASA. 37 pages, 9 figures, 1 table.
Revised version: corrected problem in Fig
Análise do equilíbrio em pacientes diabéticos por meio do sistema F-Scan e da Escala de Equilíbrio de Berg
The 14-3-3ζ Protein Binds to the Cell Adhesion Molecule L1, Promotes L1 Phosphorylation by CKII and Influences L1-Dependent Neurite Outgrowth
BACKGROUND: The cell adhesion molecule L1 is crucial for mammalian nervous system development. L1 acts as a mediator of signaling events through its intracellular domain, which comprises a putative binding site for 14-3-3 proteins. These regulators of diverse cellular processes are abundant in the brain and preferentially expressed by neurons. In this study, we investigated whether L1 interacts with 14-3-3 proteins, how this interaction is mediated, and whether 14-3-3 proteins influence the function of L1. METHODOLOGY/PRINCIPAL FINDINGS: By immunoprecipitation, we demonstrated that 14-3-3 proteins are associated with L1 in mouse brain. The site of 14-3-3 interaction in the L1 intracellular domain (L1ICD), which was identified by site-directed mutagenesis and direct binding assays, is phosphorylated by casein kinase II (CKII), and CKII phosphorylation of the L1ICD enhances binding of the 14-3-3 zeta isoform (14-3-3ζ). Interestingly, in an in vitro phosphorylation assay, 14-3-3ζ promoted CKII-dependent phosphorylation of the L1ICD. Given that L1 phosphorylation by CKII has been implicated in L1-triggered axonal elongation, we investigated the influence of 14-3-3ζ on L1-dependent neurite outgrowth. We found that expression of a mutated form of 14-3-3ζ, which impairs interactions of 14-3-3ζ with its binding partners, stimulated neurite elongation from cultured rat hippocampal neurons, supporting a functional connection between L1 and 14-3-3ζ. CONCLUSIONS/SIGNIFICANCE: Our results suggest that 14-3-3ζ, a novel direct binding partner of the L1ICD, promotes L1 phosphorylation by CKII in the central nervous system, and regulates neurite outgrowth, an important biological process triggered by L1
Determining the efficacy of guppies and pyriproxyfen (Sumilarv® 2MR) combined with community engagement on dengue vectors in Cambodia: study protocol for a randomized controlled trial
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