1,489 research outputs found
String Branchings on Complex Tori and Algebraic Representations of Generalized Krichever-Novikov Algebras
The propagation differential for bosonic strings on a complex torus with
three symmetric punctures is investigated. We study deformation aspects between
two point and three point differentials as well as the behaviour of the
corresponding Krichever-Novikov algebras. The structure constants are
calculated and from this we derive a central extension of the Krichever-Novikov
algebras by means of b-c systems. The defining cocycle for this central
extension deforms to the well known Virasoro cocycle for certain kinds of
degenerations of the torus.
AMS subject classification (1991): 17B66, 17B90, 14H52, 30F30, 81T40Comment: 11 pages, amste
Evaluating the impact of air pollution on the incidence of out-of-hospital cardiac arrest in the Perth Metropolitan Region: 2000â2010
Background: Out-of-hospital cardiac arrest (OHCA) remains a major public health issue. Several studies have found that an increased level of ambient particulate matter (PM) smaller than 2.5 microns (PM2.5) is associated with an increased risk of OHCA. We investigated the relationship between air pollution levels and the incidence of OHCA in Perth, Western Australia.Methods: We linked St John Ambulance OHCA data of presumed cardiac aetiology with Perth air pollution data from seven monitors which recorded hourly levels of PM smaller than 2.5 and 10 microns (PM2.5/PM10), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3). We used a case-crossover design to estimate the strength of association between ambient air pollution levels and risk of OHCA.Methods: We linked St John Ambulance OHCA data of presumed cardiac aetiology with Perth air pollution data from seven monitors which recorded hourly levels of PM smaller than 2.5 and 10 microns (PM2.5/PM10), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3). We used a case-crossover design to estimate the strength of association between ambient air pollution levels and risk of OHCA.Conclusions: Elevated ambient PM2.5 and CO are associated with an increased risk of OHCA
Bell Inequalities with Auxiliary Communication
What is the communication cost of simulating the correlations produced by
quantum theory? We generalize Bell inequalities to the setting of local
realistic theories augmented by a fixed amount of classical communication.
Suppose two parties choose one of M two-outcome measurements and exchange 1 bit
of information. We present the complete set of inequalities for M = 2, and the
complete set of inequalities for the joint correlation observable for M = 3. We
find that correlations produced by quantum theory satisfy both of these sets of
inequalities. One bit of communication is therefore sufficient to simulate
quantum correlations in both of these scenarios.Comment: 5 page
Determining the accuracy of zero-flux and ingestible thermometers in the peri-operative setting
Accurately monitoring peri-operative core temperature is a cornerstone of good practice. Relatively invasive devices such as oesophageal temperature probes and pulmonary artery catheters facilitate this, but are inappropriate for many patients. There remains a need for accurate monitors of core temperature that can be used in awake patients. This study compared the accuracy of two core temperature thermometers that can be used for this purpose: the 3M Bair Huggerâą Temperature Monitoring System Zero Flux Thermometer and the CorTempRâą Wireless Ingestible Temperature Sensor. Readings were compared with the oesophageal probe, the current intraoperative standard. Thirty patients undergoing elective surgical procedures under general anaesthesia were recruited. The ingestible sensor was ingested prior to induction of anaethesia, and post induction, the zero-flux electrode attached above the right eyebrow and oesophageal probe inserted. During surgery, the temperature on each device was recorded every minute. Measurements were compared using BlandâAltman analysis. The ingestible sensor experienced interference from use of diathermy and fluoroscopy in the operating theatre, rendering 39% of its readings unusable. These were removed from analysis. With remaining readings the bias compared with oesophageal probe was +â0.42 °C, with 95% limits of agreement ââ2.4 °C to 3.2 °C. 75.4% of readings were within ±â0.5 °C of the OTP reading. The bias for the zero flux electrode compared to oesophageal probe was +â0.02 °C with 95% limits of agreement ââ0.5 °C to 0.5 °C. 97.7% of readings were within ±â0.5 °C of the oesophageal probe. The study findings suggest the zero-flux thermometer is sufficiently accurate for clinical use, whereas the ingestible sensor is not
Contact Representations of Graphs in 3D
We study contact representations of graphs in which vertices are represented
by axis-aligned polyhedra in 3D and edges are realized by non-zero area common
boundaries between corresponding polyhedra. We show that for every 3-connected
planar graph, there exists a simultaneous representation of the graph and its
dual with 3D boxes. We give a linear-time algorithm for constructing such a
representation. This result extends the existing primal-dual contact
representations of planar graphs in 2D using circles and triangles. While
contact graphs in 2D directly correspond to planar graphs, we next study
representations of non-planar graphs in 3D. In particular we consider
representations of optimal 1-planar graphs. A graph is 1-planar if there exists
a drawing in the plane where each edge is crossed at most once, and an optimal
n-vertex 1-planar graph has the maximum (4n - 8) number of edges. We describe a
linear-time algorithm for representing optimal 1-planar graphs without
separating 4-cycles with 3D boxes. However, not every optimal 1-planar graph
admits a representation with boxes. Hence, we consider contact representations
with the next simplest axis-aligned 3D object, L-shaped polyhedra. We provide a
quadratic-time algorithm for representing optimal 1-planar graph with L-shaped
polyhedra
Effect of increasing fruit and vegetable intake by dietary intervention on nutritional biomarkers and attitudes to dietary change : a randomised trial
This work was funded by The Scottish Government Rural and Environmental Science and Analytical Sciences Division (RESAS) and supported by the Rank Prize Funds.Peer reviewedPublisher PD
Evidence-based paramedic models of care to reduce unnecessary emergency department attendance â feasibility and safety
Background: As demand for Emergency Department (ED) services continues to exceed increases explained by population growth, strategies to reduce ED presentations are being explored. The concept of ambulance paramedics providing an alternative model of care to the current default âsee and transport to EDâ has intuitive appeal and has been implemented in several locations around the world. The premise is that for certain noncritical ill patients, the Extended Care Paramedic (ECP) can either âsee and treatâ or âsee and referâ to another primary or community care practitioner, rather than transport to hospital. However, there has been little rigorous investigation of which types of patients can be safely identified and managed in the community, or the impact of ECPs on ED attendance.Methods/Design: St John Ambulance Western Australia paramedics will indicate on the electronic patient care record (e-PCR) of patients attended in the Perth metropolitan area if they consider them to be suitable to be managed in the community. âFollow-upâ will examine these patients using ED data to determine the patientâs disposition from the ED. A clinical panel will then develop a protocol to identify those patients who can be safely managed in the community. Paramedics will then assess patients against the derived ECP protocols and identify those deemed suitable to âsee and treatâ or âsee and referâ. The ED disposition (and other clinical outcomes) of these âECP protocol identifiedâ patients will enable us to assess whether it would have been appropriate to manage these patients in the community. We will also âtrackâ re-presentations to EDs within seven days of the initial presentation. This is a âvirtual experimentâ with no direct involvement of patients or changes in clinical practice. A systems modelling approach will be used to assess the likely impact on ED crowding.Discussion: To date the efficacy, cost-effectiveness and safety of alternative community-based models of emergency care have not been rigorously investigated. This study will inform the development of ECP protocols through the identification of types of patient presentation that can be considered both safe and appropriate for paramedics to manage in the community
Clinical effectiveness and cost-effectiveness of body psychotherapy in the treatment of negative symptoms of schizophrenia: a multicentre randomised controlled trial
BACKGROUND
The negative symptoms of schizophrenia significantly impact on quality of life and social functioning, and current treatment options are limited. In this study the clinical effectiveness and cost-effectiveness of group body psychotherapy as a treatment for negative symptoms were compared with an active control.
DESIGN
A parallel-arm, multisite randomised controlled trial. Randomisation was conducted independently of the research team, using a 1â:â1 computer-generated sequence. Assessors and statisticians were blinded to treatment allocation. Analysis was conducted following the intention-to-treat principle. In the cost-effectiveness analysis, a health and social care perspective was adopted.
PARTICIPANTS
ELIGIBILITY CRITERIA
age 18-65 years; diagnosis of schizophrenia with symptoms present at >â6 months; score of â„â18 on Positive and Negative Syndrome Scale (PANSS) negative symptoms subscale; no change in medication type in past 6 weeks; willingness to participate; ability to give informed consent; and community outpatient.
EXCLUSION CRITERIA
inability to participate in the groups and insufficient command of English.
SETTINGS
Participants were recruited from NHS mental health community services in five different Trusts. All groups took place in local community spaces.
INTERVENTIONS
Control intervention: a 10-week, 90-minute, 20-session group beginners' Pilates class, run by a qualified Pilates instructor. Treatment intervention: a 10-week, 90-minute, 20-session manualised group body psychotherapy group, run by a qualified dance movement psychotherapist.
OUTCOMES
The primary outcome was the PANSS negative symptoms subscale score at end of treatment. Secondary outcomes included measures of psychopathology, functional, social, service use and treatment satisfaction outcomes, both at treatment end and at 6-month follow-up.
RESULTS
A total of 275 participants were randomised (140 body psychotherapy group, 135 Pilates group). At the end of treatment, 264 participants were assessed (137 body psychotherapy group, 127 Pilates group). The adjusted difference in means of the PANSS negative subscale at the end of treatment was 0.03 [95% confidence interval (CI) -1.11 to 1.17], showing no advantage of the intervention. In the secondary outcomes, the mean difference in the Clinical Assessment Interview for negative symptoms expression subscale at the end of treatment was 0.62 (95% CI -1.23 to 0.00), and in extrapyramidal movement disorder symptoms -0.65 (95% CI -1.13 to -0.16) at the end of treatment and -0.58 (95% CI -1.07 to -0.09) at 6 months' follow-up, showing a small significant advantage of body psychotherapy. No serious adverse events related to the interventions were reported. The total costs of the intervention were comparable with the control, with no clear evidence of cost-effectiveness for either condition.
LIMITATIONS
Owing to the absence of a treatment-as-usual arm, it is difficult to determine whether or not both arms are an improvement over routine care.
CONCLUSIONS
In comparison with an active control, group body psychotherapy does not have a clinically relevant beneficial effect in the treatment of patients with negative symptoms of schizophrenia. These findings conflict with the review that led to the current National Institute for Health and Care Excellence guidelines suggesting that arts therapies may be an effective treatment for negative symptoms.
FUTURE WORK
Determining whether or not this lack of effectiveness extends to all types of art therapies would be informative.
TRIAL REGISTRATION
Current Controlled Trials ISRCTN842165587.
FUNDING
This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 11. See the NIHR Journals Library website for further project information
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