50 research outputs found
The Iron K Line Profile of IRAS 18325-5926
IRAS 18325-5926 is an X-ray bright, Compton-thin, type-2 Seyfert galaxy and
it was the first Seyfert 2 in which the presence of a broad Fe K-alpha emission
line was claimed. However, although the structure of the Fe line appears broad,
there is tentative evidence that it may comprise multiple lines. Nevertheless,
previous analyses have only consisted of fitting standalone broad components to
the Fe K band. Here, we have analyzed all available X-ray CCD data from Suzaku,
XMM-Newton and ASCA to fully investigate the nature of the emission complex by
testing broad-band physical models and alternative hypotheses. We find that
both a model consisting of broad, blurred reflection from an ionized accretion
disc and a model consisting of cold, neutral reflection plus narrow emission
lines from highly-ionized photoionized gas (log \xi = 3.5) offer statistically
comparable fits to the data although the true reality of the Fe line cannot
currently be determined with existing data. However, it is hoped that better
quality data and improved photon statistics in the Fe K band will allow a more
robust distinction between models to be made.Comment: Accepted by MNRAS; 13 pages; 10 figures; 2 table
Imprints of a high velocity wind on the soft x-ray spectrum of PG 1211+143
An extended XMM-Newton observation of the luminous narrow line Seyfert galaxy
PG 1211+143 in 2014 has revealed a more complex high velocity wind, with
components distinguished in velocity, ionization level, and column density.
Here we report soft x-ray emission and absorption features from the ionized
outflow, finding counterparts of both high velocity components, v ~ 0.129c and
v ~ 0.066c, recently identified in the highly ionized Fe K absorption spectrum.
The lower ionization of the co-moving soft x-ray absorbers imply a distribution
of higher density clouds embedded in the main outflow, while much higher column
densities for the same flow component in the hard x-ray spectra suggest
differing sight lines to the continuum x-ray source.Comment: 8 pages, 5 figures, 4 tables; Accepted for publication in MNRA
Rapid Variability of the accretion disk wind in the narrow line Seyfert 1, PG 1448+273
PG 1448+273 is a luminous, nearby (), narrow line Seyfert 1 galaxy,
which likely accretes close to the Eddington limit. XMM-Newton observations of
PG 1448+273 in 2017 revealed the presence of an ultra fast outflow, as seen
through its blueshifted iron K absorption profile, with an outflow velocity of
about . Here, the first NuSTAR observation of PG 1448+273, performed in
2022 and coordinated with XMM-Newton is presented, which shows remarkable
variability of its ultra fast outflow. The average count rate is a factor of 2
lower during the last 60 ks of the NuSTAR observation, where a much faster
component of the ultra fast outflow was detected with a terminal velocity of
. This is significantly faster than the outflow component which
was initially detected in 2017, when overall PG 1448+273 was observed at a
lower X-ray flux and which implies an order of magnitude increase in the wind
kinetic power between the 2017 and 2022 epochs. Furthermore, the rapid
variability of the ultra fast outflow in 2022, on timescales down to 10 ks,
suggests we are viewing through a highly inhomogeneous disk wind in PG
1448+273, where the passage of a denser wind clump could account for the
increase in obscuration in the last 60 ks of the NuSTAR observation.Comment: 15 pages, 10 figures, accepted for publication in the Astrophysical
Journa
Randomised evaluation of modified valsalva effectiveness in re-entrant tachycardias (REVERT) study
Introduction: The Valsalva manoeuvre (VM) is a recommended first-line physical treatment for patients with re-entrant supraventricular tachycardia (SVT), but is often ineffective in standard practice. A failed VM is typically followed by treatment with intravenous adenosine, which patients often find unpleasant. VM effectiveness might be improved by a modification to posture which exaggerates the manoeuvre's vagal response and reduces the need for further emergency treatment. Methods and analysis: This is a multicentre randomised controlled clinical trial in 10 UK emergency departments (EDs). It compares a standard VM with a modified VM incorporating leg elevation and a supine posture after a standardised strain in stable adult patients presenting to the ED with SVT. The primary outcome measure is return to sinus rhythm on a 12-lead ECG. Secondary outcome measures include the need for treatment with adenosine or other antiarrhythmic treatments and the time patients spend in the ED. We plan to recruit approximately 372 patients, with 80% power to demonstrate an absolute improvement in cardioversion rate of 12%. An improvement of this magnitude through the use of a modified VM would be of significant benefit to patients and healthcare providers, and justify a change to standard practice. Ethics and dissemination: The study has been approved by the South West - Exeter Research Ethics Committee (REC reference 12/SW/0281). The trial will be published in an international peer reviewed journal. Study findings will be sent to the European and International resuscitation councils to inform future revisions of arrhythmia management guidelines. Results: The trial will also be disseminated at international conferences and to patients through the Arrhythmia Alliance, a patient support charity. Registration: The study is registered with Current Controlled Trials (ISRCTN67937027) and has been adopted by the National Institute for Health Research (NIHR) Clinical Research Network
Postural modification to the standard Valsalva manoeuvre for emergency treatment of supraventricular tachycardias (REVERT): A randomised controlled trial
© 2015 Appelboam et al. Open Access article distributed under the terms of CC BY-ND-NC. Background The Valsalva manoeuvre is an internationally recommended treatment for supraventricular tachycardia, but cardioversion is rare in practice (5-20%), necessitating the use of other treatments including adenosine, which patients often find unpleasant. We assessed whether a postural modification to the Valsalva manoeuvre could improve its effectiveness. Methods We did a randomised controlled, parallel-group trial at emergency departments in England. We randomly allocated adults presenting with supraventricular tachycardia (excluding atrial fibrillation and flutter) in a 1:1 ratio to undergo a modified Valsalva manoeuvre (done semi-recumbent with supine repositioning and passive leg raise immediately after the Valsalva strain), or a standard semi-recumbent Valsalva manoeuvre. A 40 mm Hg pressure, 15 s standardised strain was used in both groups. Randomisation, stratified by centre, was done centrally and independently, with allocation with serially numbered, opaque, sealed, tamper-evident envelopes. Patients and treating clinicians were not masked to allocation. The primary outcome was return to sinus rhythm at 1 min after intervention, determined by the treating clinician and electrocardiogram and confirmed by an investigator masked to treatment allocation. This study is registered with Current Controlled Trials (ISRCTN67937027). Findings We enrolled 433 participants between Jan 11, 2013, and Dec 29, 2014. Excluding second attendance by five participants, 214 participants in each group were included in the intention-to-treat analysis. 37 (17%) of 214 participants assigned to standard Valsalva manoeuvre achieved sinus rhythm compared with 93 (43%) of 214 in the modified Valsalva manoeuvre group (adjusted odds ratio 3·7 (95% CI 2·3-5·8;
Neural processing of criticism and positive comments from relatives in individuals with schizotypal personality traits
Objectives. High negative expressed emotion by family members towards schizophrenia patients increases the risk of subsequent relapse. The study aimed to determine whether individuals with high schizotypy (HS) and low schizotypy (LS) would differ in activation of brain areas involved in cognitive control when listening to relative criticism
Demographic predictors of wellbeing in Carers of people with psychosis: secondary analysis of trial data
Background: Carers of people with psychosis are at a greater risk of physical and mental health problems
compared to the general population. Yet, not all carers will experience a decline in health. This predicament has
provided the rationale for research studies exploring what factors predict poor wellbeing in carers of people with
psychosis. Our study builds on previous research by testing the predictive value of demographic variables on carer
wellbeing within a single regression model.
Methods: To achieve this aim, we conducted secondary analysis on two trial data sets that were merged and
recoded for the purposes of this study. Results: Contrary to our hypotheses, only carer gender and age predicted
carer wellbeing; with lower levels of carer wellbeing being associated with being female or younger (aged under
50). However, the final regression model explained only 11% of the total variance.
Conclusions: Suggestions for future research are discussed in light of the limitations inherent in secondary analysis
studies. Further research is needed where sample sizes are sufficient to explore the interactive and additive impact
of other predictor variables
Consultant psychiatrists’ experiences of and attitudes towards shared decision making in antipsychotic prescribing, a qualitative study
Background: Shared decision making represents a clinical consultation model where both clinician and service user are conceptualised as experts; information is shared bilaterally and joint treatment decisions are reached. Little previous research has been conducted to assess experience of this model in psychiatric practice. The current project therefore sought to explore the attitudes and experiences of consultant psychiatrists relating to shared decision making in the prescribing of antipsychotic medications. Methods: A qualitative research design allowed the experiences and beliefs of participants in relation to shared decision making to be elicited. Purposive sampling was used to recruit participants from a range of clinical backgrounds and with varying length of clinical experience. A semi-structured interview schedule was utilised and was adapted in subsequent interviews to reflect emergent themes. Data analysis was completed in parallel with interviews in order to guide interview topics and to inform recruitment. A directed analysis method was utilised for interview analysis with themes identified being fitted to a framework identified from the research literature as applicable to the practice of shared decision making. Examples of themes contradictory to, or not adequately explained by, the framework were sought. Results: A total of 26 consultant psychiatrists were interviewed. Participants expressed support for the shared decision making model, but also acknowledged that it was necessary to be flexible as the clinical situation dictated. A number of potential barriers to the process were perceived however: The commonest barrier was the clinician's beliefs regarding the service users' insight into their mental disorder, presented in some cases as an absolute barrier to shared decision making. In addition factors external to the clinician - service user relationship were identified as impacting on the decision making process, including; environmental factors, financial constraints as well as societal perceptions of mental disorder in general and antipsychotic medication in particular. Conclusions: This project has allowed identification of potential barriers to shared decision making in psychiatric practice. Further work is necessary to observe the decision making process in clinical practice and also to identify means in which the identified barriers, in particular 'lack of insight', may be more effectively managed. © 2014 Shepherd et al.; licensee BioMed Central Ltd