90 research outputs found

    Interruption of torus doubling bifurcation and genesis of strange nonchaotic attractors in a quasiperiodically forced map : Mechanisms and their characterizations

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    A simple quasiperiodically forced one-dimensional cubic map is shown to exhibit very many types of routes to chaos via strange nonchaotic attractors (SNAs) with reference to a two-parameter (A−f)(A-f) space. The routes include transitions to chaos via SNAs from both one frequency torus and period doubled torus. In the former case, we identify the fractalization and type I intermittency routes. In the latter case, we point out that atleast four distinct routes through which the truncation of torus doubling bifurcation and the birth of SNAs take place in this model. In particular, the formation of SNAs through Heagy-Hammel, fractalization and type--III intermittent mechanisms are described. In addition, it has been found that in this system there are some regions in the parameter space where a novel dynamics involving a sudden expansion of the attractor which tames the growth of period-doubling bifurcation takes place, giving birth to SNA. The SNAs created through different mechanisms are characterized by the behaviour of the Lyapunov exponents and their variance, by the estimation of phase sensitivity exponent as well as through the distribution of finite-time Lyapunov exponents.Comment: 27 pages, RevTeX 4, 16 EPS figures. Phys. Rev. E (2001) to appea

    The smoking cessation in pregnancy incentives trial (CPIT): study protocol for a phase III randomised controlled trial

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    Background: Eighty per cent of UK women have at least one baby, making pregnancy an opportunity to help women stop smoking before their health is irreparably compromised. Smoking cessation during pregnancy helps protect infants from miscarriage, still birth, low birth weight, asthma, attention deficit disorder and adult cardiovascular disease. UK national guidelines highlight lack of evidence for effectiveness of financial incentives to help pregnant smokers quit. This includes a research recommendation: within a UK context, are incentives an acceptable, effective and cost-effective way to help pregnant women who smoke to quit? Methods: The Cessation in Pregnancy Incentives Trial (CPIT) III is a pragmatic, 42-month, multi-centre, parallel-group, individually randomised controlled superiority trial of the effect on smoking status of adding to usual Stop Smoking Services (SSS) support, the offer of up to £400 of financial voucher incentives, compared with usual support alone, to quit smoking during pregnancy. Participants (n = 940) are pregnant smokers (age > 16 years, < 24 weeks pregnant, English speaking), who consent via telephone to take part and are willing to be followed-up in late pregnancy and 6 months after birth. The primary outcome is cotinine/anabasine-validated abstinence from smoking in late pregnancy. Secondary outcomes include engagement with SSS, quit rates at 4 weeks from agreed quit date and 6 months after birth, and birth weight. Outcomes will be analysed by intention to treat, and regression models will be used to compare treatment effects on outcomes. A meta-analysis will include data from the feasibility study in Glasgow. An economic evaluation will assess cost-effectiveness from a UK NHS perspective. Process evaluation using a case-study approach will identify opportunities to improve recruitment and learning for future implementation. Research questions include: what is the therapeutic efficacy of incentives; are incentives cost-effective; and what are the potential facilitators and barriers to implementing incentives in different parts of the UK? Discussion: This phase III trial in Scotland, England and Northern Ireland follows a successful phase II trial in Glasgow, UK. The participating sites have diverse SSS that represent most cessation services in the UK and serve demographically varied populations. If found to be acceptable and cost-effective, this trial could demonstrate that financial incentives are effective and transferable to most UK SSS for pregnant women. Trial registration: Current Controlled Trials, ISRCTN15236311. Registered on 9 October 2017

    Bereavement following a fatal overdose: The experiences of adults in England and Scotland

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    Aims: Overdoses contribute disproportionately to drug-related deaths (DRDs) in the UK, yet little is known about the experiences and needs of those who are bereaved by such deaths, and how their experiences and needs might differ from other bereavements associated with substance use. Methods: An interview study with 32 adults in England and Scotland (part of a larger study). Findings: Five themes describe the core experiences of this group of bereaved people: drug use, the death, official processes, stigma, and overdose awareness and prevention. Together, these findings offer new insights in to the key features of this type of bereavement; for example, living with substance use including previous overdoses, difficult circumstances surrounding the death, having to negotiate the complex procedures involved in processing the death, the stigma such deaths attract, and feelings of guilt, self-blame and an unworthiness to grieve. Conclusions: There are ways in which bereavement following an overdose differs from bereavement following other deaths associated with alcohol or drugs. Understanding the experiences and needs of this marginalised group can help improve support for them. Furthermore, this group’s experience of witnessing and/or responding to previous overdoses indicates the value in prevention programmes targeting relatives/friends. © 2016 The Author(s). Published by Taylor & Francis

    Effect of financial voucher incentives provided with UK stop smoking services on the cessation of smoking in pregnant women (CPIT III): pragmatic, multicentre, single blinded, phase 3, randomised controlled trial.

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    OBJECTIVE: To examine effectiveness, cost effectiveness, generalisability, and acceptability of financial incentives for smoking cessation during pregnancy in addition to variously organised UK stop smoking services. DESIGN: Pragmatic, multicentre, single blinded, phase 3, randomised controlled trial (Cessation in Pregnancy Incentives Trial phase 3 (CPIT III)). SETTING: Seven UK stop smoking services provided in primary and secondary care facilities in Scotland, Northern Ireland, and England. PARTICIPANTS: 944 pregnant women (age ≥16 years) who self-reported as being smokers (at least one cigarette in the past week) when asked at first maternity visit, less than 24 weeks' gestation, and notified to the trial team by routine stop smoking services. INTERVENTIONS: Participants in the control group were offered the standard stop smoking services, which includes the offer of counselling by specially trained workers using withdrawal orientated therapy and the offer of free nicotine replacement therapy. The intervention was the offer of usual support from the stop smoking services and the addition of up to £400 ($440; €455) of LoveToShop financial voucher incentives for engaging with current stop smoking services or to stop smoking, or both, during pregnancy. MAIN OUTCOME MEASURES: Self-reported smoking cessation in late pregnancy (between 34 and 38 weeks' gestation) corroborated by saliva cotinine (and anabasine if using nicotine replacement products). Results were adjusted for age, smoking years, index of multiple deprivation, Fagerström score, before or after covid, and recruitment site. Secondary outcomes included point and continuous abstinence six months after expected date of delivery, engagement with stop smoking services, biochemically validated abstinence from smoking at four weeks after stop smoking date, birth weight of baby, cost effectiveness, generalisability documenting formats of stop smoking services, and acceptability to pregnant women and their carers. RESULTS: From 9 January 2018 to 4 April 2020, of 4032 women screened by stop smoking services, 944 people were randomly assigned to the intervention group (n=471) or the control group (n=470). Three people asked for their data to be removed. 126 (27%) of 471 participants stopped smoking from the intervention group and 58 (12%) of 470 from the control group (adjusted odds ratio 2.78 (1.94 to 3.97) P<0.001). Serious adverse events were miscarriages and other expected pregnancy events requiring hospital admission; all serious adverse events were unrelated to the intervention. Most people who stopped smoking from both groups relapsed after their baby was born. CONCLUSIONS: The offer of up to £400 of financial voucher incentives to stop smoking during pregnancy as an addition to current UK stop smoking services is highly effective. This bolt-on intervention supports new guidance from the UK National Institute for Health and Care Excellence, which includes the addition of financial incentives to support pregnant women to stop smoking. Continuing incentives to 12 months after birth is being examined to prevent relapse. TRIAL REGISTRATION: ISRCTN Registry ISRCTN15236311

    Particulate Matter-Induced Lung Inflammation Increases Systemic Levels of PAI-1 and Activates Coagulation Through Distinct Mechanisms

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    Exposure of human populations to ambient particulate matter (PM) air pollution significantly contributes to the mortality attributable to ischemic cardiovascular events. We reported that mice treated with intratracheally instilled PM develop a prothrombotic state that requires the release of IL-6 by alveolar macrophages. We sought to determine whether exposure of mice to PM increases the levels of PAI-1, a major regulator of thrombolysis, via a similar or distinct mechanism. mice but was absent in mice treated with etanercept, a TNF-α inhibitor. Treatment with etanercept did not prevent the PM-induced tendency toward thrombus formation.Mice exposed to inhaled PM exhibited a TNF-α-dependent increase in PAI-1 and an IL-6-dependent activation of coagulation. These results suggest that multiple mechanisms link PM-induced lung inflammation with the development of a prothrombotic state

    Transcriptional Analysis of Murine Macrophages Infected with Different Toxoplasma Strains Identifies Novel Regulation of Host Signaling Pathways

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    Most isolates of Toxoplasma from Europe and North America fall into one of three genetically distinct clonal lineages, the type I, II and III lineages. However, in South America these strains are rarely isolated and instead a great variety of other strains are found. T. gondii strains differ widely in a number of phenotypes in mice, such as virulence, persistence, oral infectivity, migratory capacity, induction of cytokine expression and modulation of host gene expression. The outcome of toxoplasmosis in patients is also variable and we hypothesize that, besides host and environmental factors, the genotype of the parasite strain plays a major role. The molecular basis for these differences in pathogenesis, especially in strains other than the clonal lineages, remains largely unexplored. Macrophages play an essential role in the early immune response against T. gondii and are also the cell type preferentially infected in vivo. To determine if non-canonical Toxoplasma strains have unique interactions with the host cell, we infected murine macrophages with 29 different Toxoplasma strains, representing global diversity, and used RNA-sequencing to determine host and parasite transcriptomes. We identified large differences between strains in the expression level of known parasite effectors and large chromosomal structural variation in some strains. We also identified novel strain-specifically regulated host pathways, including the regulation of the type I interferon response by some atypical strains. IFNβ production by infected cells was associated with parasite killing, independent of interferon gamma activation, and dependent on endosomal Toll-like receptors in macrophages and the cytoplasmic receptor retinoic acid-inducible gene 1 (RIG-I) in fibroblasts.National Institutes of Health (U.S.) (R01-AI080621)New England Regional Center of Excellence for Biodefense and Emerging Infectious Diseases (Developmental Grant AIO57159)Pew Charitable Trusts (Biomedical Scholars Program)Robert A. Swanson Career Development awardThe Knights Templar Eye Foundation, Inc.Pre-Doctoral Grant in the Biological Sciences (5-T32-GM007287-33)Cleo and Paul Schimmel Foundatio

    Role of Annual Grasses and Shrubs in Nutrient Cycling of Great Basin Communites

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    Letter dated 2 December 1967 from Cyrus and Betty McKell to Lorenzo and Zilla Richards

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    Letter dated 2 December 1967 from Cyrus and Betty McKell in Madrid, Spain, to Lorenzo and Zilla Richards, thanking them for hospitality before they left for Spain, and relating their experiences getting settled near Madrid, where McKell was on sabbatica
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