5,847 research outputs found
Thromboembolic and neurologic sequelae of discontinuation of an antihyperlipidemic drug during ongoing warfarin therapy
Warfarin and antihyperlipidemics are commonly co-prescribed. Some antihyperlipidemics may inhibit warfarin deactivation via the hepatic cytochrome P450 system. Therefore, antihyperlipidemic discontinuation has been hypothesized to result in underanticoagulation, as warfarin metabolism is no longer inhibited. We quantified the risk of venous thromboembolism (VTE) and ischemic stroke (IS) due to statin and fibrate discontinuation in warfarin users, in which warfarin was initially dose-titrated during ongoing antihyperlipidemic therapy. Using 1999-2011 United States Medicaid claims among 69 million beneficiaries, we conducted a set of bidirectional self-controlled case series studies-one for each antihyperlipidemic. Outcomes were hospital admissions for VTE/IS. The risk segment was a maximum of 90 days immediately following antihyperlipidemic discontinuation, the exposure of interest. Time-varying confounders were included in conditional Poisson models. We identified 629 study eligible-persons with at least one outcome. Adjusted incidence rate ratios (IRRs) for all antihyperlipidemics studied were consistent with the null, and ranged from 0.21 (0.02, 2.82) for rosuvastatin to 2.16 (0.06, 75.0) for gemfibrozil. Despite using an underlying dataset of millions of persons, we had little precision in estimating IRRs for VTE/IS among warfarin-treated persons discontinuing individual antihyperlipidemics. Further research should investigate whether discontinuation of gemfibrozil in warfarin users results in serious underanticoagulation
Women's responses to information about overdiagnosis in the UK breast cancer screening programme: a qualitative study.
Objectives: To explore the influence of overdiagnosis
information on women’s decisions about mammography.
Design: A qualitative focus group study with purposive sampling and thematic analysis, in which overdiagnosis information was presented.
Setting: Community and university settings in London.
Participants: 40 women within the breast screening
age range (50–71 years) including attenders and nonattenders were recruited using a recruitment agency as
well as convenience sampling methods.
Results: Women expressed surprise at the possible
extent of overdiagnosis and recognised the information as important, although many struggled to interpret the numerical data. Overdiagnosis was viewed as less personally relevant than the possibility of ‘under diagnosis’ (false negatives), and often considered to be an issue for follow-up care decisions rather than screening participation. Women also expressed concern that information on overdiagnosis could deter others from attending screening, although they rarely saw it as a deterrent. After discussing overdiagnosis, few women felt that they would make different decisions about breast
screening in the future.
Conclusions: Women regard it as important to be informed about overdiagnosis to get a complete picture of the risks and benefits of mammography, but the results of this study indicate that understanding overdiagnosis may not always influence women’s attitudes towards participation in breast screening. The results also highlight the challenge of communicating the individual significance of information derived from population-level modelling
Ultrashort pulses and short-pulse equations in dimensions
In this paper, we derive and study two versions of the short pulse equation
(SPE) in dimensions. Using Maxwell's equations as a starting point, and
suitable Kramers-Kronig formulas for the permittivity and permeability of the
medium, which are relevant, e.g., to left-handed metamaterials and dielectric
slab waveguides, we employ a multiple scales technique to obtain the relevant
models. General properties of the resulting -dimensional SPEs, including
fundamental conservation laws, as well as the Lagrangian and Hamiltonian
structure and numerical simulations for one- and two-dimensional initial data,
are presented. Ultrashort 1D breathers appear to be fairly robust, while rather
general two-dimensional localized initial conditions are transformed into
quasi-one-dimensional dispersing waveforms
Evidence for non-stellar rest-frame near-IR emission associated with increased star formation in galaxies at
We explore the presence of non-stellar rest-frame near-IR () emission in galaxies at . Previous studies identified
this excess in relatively small samples and suggested that such non-stellar
emission, which could be linked to the polycyclic
aromatic hydrocarbons feature or hot dust emission, is associated with an
increased star formation rate (SFR). In this Letter, we confirm and quantify
the presence of an IR excess in a significant fraction of galaxies in the
3D-HST GOODS catalogs. By constructing a matched sample of galaxies with and
without strong non-stellar near-IR emission, we find that galaxies with such
emission are predominantly star-forming galaxies. Moreover, star-forming
galaxies with an excess show increased mid- and far-IR and H emission
compared to other star-forming galaxies without. While galaxies with a near-IR
excess show a larger fraction of individually detected X-ray active galactic
nuclei (AGNs), an X-ray stacking analysis, together with the IR-colors and
H profiles, shows that AGNs are unlikely to be the dominant source of
the excess in the majority of galaxies. Our results suggest that non-stellar
near-IR emission is linked to increased SFRs and is ubiquitous among
star-forming galaxies. As such, the near-IR emission might be a powerful tool
to measure SFRs in the era of the James Webb Space Telescope.Comment: 6 pages, 5 figures, accepted for publication in ApJ
Fractional Quantum Hall Effect and vortex lattices
It is demonstrated that all observed fractions at moderate Landau level
fillings for the quantum Hall effect can be obtained without recourse to the
phenomenological concept of composite fermions. The possibility to have the
special topologically nontrivial many-electron wave functions is considered.
Their group classification indicates the special values of of electron density
in the ground states separated by a gap from excited states
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Women's interpretation of and responses to potential gynaecological cancer symptoms: a qualitative interview study
OBJECTIVE: To explore women's experiences of symptoms potentially indicative of gynaecological cancer in a community-based sample without imposing a cancer perspective.
DESIGN: A qualitative interview study with thematic analysis of transcripts.
PARTICIPANTS: 26 women aged ≥30 years, who had experienced a symptom that might indicate gynaecological cancer in the past 3 months, were recruited using a screening questionnaire distributed online and in community settings.
SETTING: London, UK.
RESULTS: Women attributed gynaecological symptoms to existing illnesses/conditions or considered themselves to be predisposed to them, either through their 'genes' or previous personal experience. Normalising symptoms by attributing them to demographic characteristics (e.g., age, sex) was common, as was considering them a side effect of hormonal contraception. When women raised cancer as a possible cause, they often dismissed it as unlikely. Responses to symptoms included self-management (e.g., self-medicating, making lifestyle changes), adopting a 'lay system of care', or consulting a healthcare professional. Triggers to help-seeking included persistent, painful or debilitating symptoms, concern about symptom seriousness, and feeling that help-seeking was legitimised. Barriers to help-seeking included lack of concern, vague symptoms, unusual symptom location, competing time demands, previous negative experiences with the healthcare system, and not wanting to be perceived as a time-waster.
CONCLUSIONS: Attributions of symptoms potentially indicative of a gynaecological cancer were varied, but most often involved women fitting symptoms into their expectations of what was 'normal'. Normalising acted as a barrier to seeking help from a healthcare professional, alongside competing time demands and negative attitudes towards help-seeking. These barriers may lead to later diagnosis and poorer cancer survival. Our findings could be used to inform the development of interventions to encourage appropriate help-seeking
Apollo experiment S-217 IR/radar study of Apollo data
An experiment using Earth based remote sensing radar, infrared eclipse, and color difference data to deduce surface properties not visible in Apollo photography is reported. The Earth based data provided information on the small scale (centimeter sized) blockiness and on the surface chemical composition (titanium and iron contents) of the lunar surface. These deduced surface properties complemented the new Apollo photography, leading to refined geologic interpretations of the lunar surface
Emergence of classicality in small number entangled systems
We show the transition from a fully quantized interaction to a semiclassical
one in entangled small number quantum systems using the quantum trajectories
approach. In particular, we simulate the microwave Ramsey zones used in Rydberg
atom interferometry, filling in the gap between the strongly entangling Jaynes
Cummings evolution and the semiclassical rotation of the atomic internal
states. We also correlate the information flowing with leaking photons to the
entanglement generation between cavity field and flying atom and detail the
roles played by the strong dissipation and the external driving force in
preserving atomic coherence through the interaction.Comment: 4 pages, 6 figure
Grassland biodiversity restoration increases resistance of carbon fluxes to drought
Evidence suggests that the restoration of plant diversity in grasslands not only brings benefits for biodiversity conservation, but also the delivery of ecosystem services. While biodiversity-function experiments show that greater plant diversity increases resistance of plant productivity to climate extremes, it is not known whether real-world management options for grassland restoration likewise stabilize ecosystem responses to extreme climate events. We used a long-term (23Â year) field experiment in northern England to test the hypothesis that management aimed at biodiversity restoration increases the resistance and recovery of ecosystem carbon (C) fluxes to short-term summer drought. This was tested by measuring plant, soil and microbial responses to a simulated drought in experimental grassland plots where fertilizer application and seed addition have been managed to enhance plant species diversity. The cessation of fertilizer application brought about small increases in plant species richness. Additionally, cessation of fertilizer application reduced overall plant productivity and promoted hemi-parasitic plants at the expense of grasses and forbs. Resistance of CO 2 fluxes to drought, measured as ecosystem respiration, was greater in non-fertilized plots, as lower plant biomass reduced water demand, likely aided by proportionally more hemi-parasitic plants further reducing plant biomass. Additionally, legumes increased under drought, thereby contributing to overall resistance of plant productivity. Recovery of soil microbial C and nitrogen was more rapid after rewetting than soil microbial community composition, irrespective of restoration treatment, suggesting high resilience of soil microbial communities to drought. Synthesis and applications. This study shows that while grassland diversity restoration management increases the resistance of carbon fluxes to drought, it also reduces agricultural yields, revealing a trade-off for land managers. Furthermore legumes, promoted through long-term restoration treatments, can help to maintain plant community productivity under drought by increasing their biomass. As such, grassland management strategies not only have consequences for ecosystem processes, but also the capacity to withstand extreme weather events
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