1,151 research outputs found

    Dimming the Lights: 2D Simulations of Deflagrations of Hybrid C/O/Ne White Dwarfs using FLASH

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    The dimmest and most numerous outlier of the Type Ia supernova population, Type Iax events, is increasingly being found in the results of observational campaigns. There is currently no single accepted model to describe these events. This 2D study explores the viability of modeling Type Iax events as a hybrid C/O/Ne white dwarf progenitor undergoing a deflagration using the multi-physics software FLASH. This hybrid was created using the stellar evolution code MESA, and its C-depleted core and mixed structure have demonstrated lower yields than traditional C/O progenitors in previous deflagration-to-detonation studies. To generate a sample, 30 "realizations" of this simulation were performed, the only difference being the shape of the initial matchhead used to start the deflagration. As consistent with earlier work, these realizations produce the familiar hot dense bound remnant surrounded by sparse ejecta. Our results indicate the majority of the star remains unburned (~70%) and bound (>90%). Our realizations produce total ejecta yields on the order of 102^{-2} - 101^{-1} solar masses, ejected 56^{56}Ni yields on the order of 104^{-4} - 102^{-2} solar masses, and ejecta kinetic energies on the order of 1048^{48} - 1049^{49} ergs. Compared to yields inferred from recent observations of the dimmest Type Iax events - SN 2007qd, SN 2008ha, SN 2010ae, SN 2019gsc, SN 2019muj, SN 2020kyg, and SN 2021fcg - our simulation produces comparable 56^{56}Ni yields, but too-small total yields and kinetic energies. Reignition of the remnant is also seen in some realizations.Comment: 43 pages, 15 figures, 4 tables. To be published in Ap

    Neural correlates of true and false memory in mild cognitive impairment

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    The goal of this research was to investigate the changes in neural processing in mild cognitive impairment. We measured phase synchrony, amplitudes, and event-related potentials in veridical and false memory to determine whether these differed in participants with mild cognitive impairment compared with typical, age-matched controls. Empirical mode decomposition phase locking analysis was used to assess synchrony, which is the first time this analysis technique has been applied in a complex cognitive task such as memory processing. The technique allowed assessment of changes in frontal and parietal cortex connectivity over time during a memory task, without a priori selection of frequency ranges, which has been shown previously to influence synchrony detection. Phase synchrony differed significantly in its timing and degree between participant groups in the theta and alpha frequency ranges. Timing differences suggested greater dependence on gist memory in the presence of mild cognitive impairment. The group with mild cognitive impairment had significantly more frontal theta phase locking than the controls in the absence of a significant behavioural difference in the task, providing new evidence for compensatory processing in the former group. Both groups showed greater frontal phase locking during false than true memory, suggesting increased searching when no actual memory trace was found. Significant inter-group differences in frontal alpha phase locking provided support for a role for lower and upper alpha oscillations in memory processing. Finally, fronto-parietal interaction was significantly reduced in the group with mild cognitive impairment, supporting the notion that mild cognitive impairment could represent an early stage in Alzheimer’s disease, which has been described as a ‘disconnection syndrome’

    Developing a model of short-term integrated palliative and supportive care for frail older people in community settings: perspectives of older people, carers and other key stakeholders

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    Background: Understanding how best to provide palliative care for frail older people with non-malignant conditions is an international priority. We aimed to develop a community-based episodic model of short-term integrated palliative and supportive care (SIPS) based on the views of service users and other key stakeholders in the United Kingdom. Method: Transparent expert consultations with health professionals, voluntary sector and carer representatives including a consensus survey; and focus groups with older people and carers were used to generate recommendations for the SIPS model. Discussions focused on three key components of the model: potential benefit of SIPS; timing of delivery; and processes of integrated working between specialist palliative care and generalist practitioners. Content and descriptive analysis was employed and findings integrated across the data sources. Findings: We conducted two expert consultations (n=63), a consensus survey (n=42) and three focus groups (n=17). Potential benefits of SIPS included holistic assessment, opportunity for end of life discussion, symptom management, and carer reassurance. Older people and carers advocated early access to SIPS, while other stakeholders proposed delivery based on complex symptom burden. A priority for integrated working was the assignment of a key worker to coordinate care, but the assignment criteria remain uncertain. Interpretation: Key stakeholders agree that a model of SIPS for frail older people with non-malignant conditions has potential benefits within community settings, but differ in opinion on the optimal timing and indications for this service. Our findings highlight the importance of consulting all key stakeholders in model development prior to feasibility evaluation

    Provision of palliative and end-of-life care in UK care homes during the COVID-19 pandemic: A mixed methods observational study with implications for policy

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    © 2023 Bradshaw, Ostler, Goodman, Batkovskyte, Ellis-Smith, Tunnard, Bone, Barclay, Vernon, Higginson, Evans and Sleeman. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). https://creativecommons.org/licenses/by/4.0/Introduction: Little consideration has been given to how the provision of palliative and end-of-life care in care homes was affected by COVID-19. The aims of this study were to: (i) investigate the response of UK care homes in meeting the rapidly increasing need for palliative and end-of-life care during the COVID-19 pandemic and (ii) propose policy recommendations for strengthening the provision of palliative and end-of-life care within care homes. Materials and methods: A mixed methods observational study was conducted, which incorporated (i) an online cross-sectional survey of UK care homes and (ii) qualitative interviews with care home practitioners. Participants for the survey were recruited between April and September 2021. Survey participants indicating availability to participate in an interview were recruited using a purposive sampling approach between June and October 2021. Data were integrated through analytic triangulation in which we sought areas of convergence, divergence, and complementarity. Results: There were 107 responses to the survey and 27 interviews. We found that (i) relationship-centered care is crucial to high-quality palliative and end-of-life care within care homes, but this was disrupted during the pandemic. (ii) Care homes' ability to maintain high-quality relationship-centered care required key “pillars” being in place: integration with external healthcare systems, digital inclusion, and a supported workforce. Inequities within the care home sector meant that in some services these pillars were compromised, and relationship-centered care suffered. (iii) The provision of relationship-centered care was undermined by care home staff feeling that their efforts and expertise in delivering palliative and end-of-life care often went unrecognized/undervalued. Conclusion: Relationship-centered care is a key component of high-quality palliative and end-of-life care in care homes, but this was disrupted during the COVID-19 pandemic. We identify key policy priorities to equip care homes with the resources, capacity, and expertise needed to deliver palliative and end-of-life care: (i) integration within health and social care systems, (ii) digital inclusivity, (iii) workforce development, (iv) support for care home managers, and (v) addressing (dis)parities of esteem. These policy recommendations inform, extend, and align with policies and initiatives within the UK and internationally.Peer reviewe

    Acetaminophen ingestion improves repeated sprint cycling performance in females: a randomized crossover trial

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    The aim of this study is to investigate the effect of acute acetaminophen (ACT) ingestion on eight maximal 30-second cycling bouts, interspersed with two-minute rests. Seven recreationally active females (N=7, 22.8±6.7 years of age, with a stature of 163.4±5.8 cm, and body mass of 58.9±5.9 kg) participated in a placebo-controlled, randomized crossover design. Pain perception, heart rate, and power profiles were analyzed using a time x condition repeated measures ANOVA. Blood lactate after the eighth bout and total work done were analyzed using the paired samples t-test. Participants achieved a significantly greater (p=.007, =.725) peak power output during the ACT trials (402.9±73.8 W, 95% CI=334.6–471.1 W) when compared to the placebo (PLA) trials (378.7±64.6 W, 95% CI=319.0–438.4 W). Supplementation of ACT had no effect on mean power output, blood lactate accumulation, pain perception, or total work done after eight bouts (p>.05). Data presented here suggest females can improve peak power output during repeated Wingate tests with ACT ingestion. It is proposed that the altered afferent feedback may have caused these alterations in power output

    The benefit of evolving multidisciplinary care in ALS: a diagnostic cohort survival comparison

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    BACKGROUND Care for people with amyotrophic lateral sclerosis (ALS) has altered at King's College Hospital over the last 20 years. The clinic has been a multidisciplinary, specialist, tertiary referral centre since 1995 with a large team with integrated palliative and respiratory care since 2006. We hypothesised that these changes would improve survival. METHODS In this retrospective observational study, patients diagnosed with El Escorial definite, probable and possible ALS between 1995-1998 and 2008-2011 were followed up. The primary outcome measure was a chi-square test for the proportion of each cohort surviving. Kaplan-Meier survival analysis and Cox multivariate regression were secondary analyses. RESULTS There was low reporting of some interventions. Five hundred and forty-seven people were included. Survival between the cohorts was significantly different (p = 0.022) with a higher proportion surviving during 2008-2011. Survival time was 21.6 (95% CI 19.2-24.0) months in the 2008-2011 cohort compared to 19.2 years (15.6-21.6) in the 1995-1998 cohort (log rank p = 0.018). Four hundred and ninety-three cases were included in the Cox regression. Diagnostic cohort was a significant predictor variable (HR 0.79 (0.64-0.97) p = 0.023). CONCLUSIONS These results support the hypothesis that integrated specialist clinics with multidisciplinary input improve survival in ALS

    A prospective cohort study assessing clinical referral management & workforce allocation within a UK regional medical genetics service

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    Abstract Ensuring patient access to genomic information in the face of increasing demand requires clinicians to develop innovative ways of working. This paper presents the first empirical prospective observational cohort study of UK multi-disciplinary genetic service delivery. It describes and explores collaborative working practices including the utilisation and role of clinical geneticists and non-medical genetic counsellors. Six hundred and fifty new patients referred to a regional genetics service were tracked through 850 clinical contacts until discharge. Referral decisions regarding allocation of lead health professional assigned to the case were monitored, including the use of initial clinical contact guidelines. Significant differences were found in the cases led by genetic counsellors and those led by clinical geneticists. Around a sixth, 16.8% (109/650) of referrals were dealt with by a letter back to the referrer or re-directed to another service provider and 14.8% (80/541) of the remaining patients chose not to schedule an appointment. Of the remaining 461 patients, genetic counsellors were allocated as lead health professional for 46.2% (213/461). A further 61 patients did not attend. Of those who did, 86% (345/400) were discharged after one or two appointments. Genetic counsellors contributed to 95% (784/825) of total patient contacts. They provided 93.7% (395/432) of initial contacts and 26.8% (106/395) of patients were discharged at that point. The information from this study informed a planned service re-design. More research is needed to assess the effectiveness and efficiency of different models of collaborative multi-disciplinary working within genetics services. Keywords (MeSH terms) Genetic Services, Genetic Counseling, Interdisciplinary Communication, Cohort Studies, Delivery of Healthcare, Referral and Consultation

    Proliferation and estrogen signaling can distinguish patients at risk for early versus late relapse among estrogen receptor positive breast cancers

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    Introduction: We examined if a combination of proliferation markers and estrogen receptor (ER) activity could predict early versus late relapses in ER-positive breast cancer and inform the choice and length of adjuvant endocrine therapy. Methods: Baseline affymetrix gene-expression profiles from ER-positive patients who received no systemic therapy (n = 559), adjuvant tamoxifen for 5 years (cohort-1: n = 683, cohort-2: n = 282) and from 58 patients treated with neoadjuvant letrozole for 3 months (gene-expression available at baseline, 14 and 90 days) were analyzed. A proliferation score based on the expression of mitotic kinases (MKS) and an ER-related score (ERS) adopted from Oncotype DX® were calculated. The same analysis was performed using the Genomic Grade Index as proliferation marker and the luminal gene score from the PAM50 classifier as measure of estrogen-related genes. Median values were used to define low and high marker groups and four combinations were created. Relapses were grouped into time cohorts of 0-2.5, 0-5, 5-10 years. Results: In the overall 10 years period, the proportional hazards assumption was violated for several biomarker groups indicating time-dependent effects. In tamoxifen-treated patients Low-MKS/Low-ERS cancers had continuously increasing risk of relapse that was higher after 5 years than Low-MKS/High-ERS cancers [0 to 10 year, HR 3.36; p = 0.013]. High-MKS/High-ERS cancers had low risk of early relapse [0-2.5 years HR 0.13; p = 0.0006], but high risk of late relapse which was higher than in the High-MKS/Low-ERS group [after 5 years HR 3.86; p = 0.007]. The High-MKS/Low-ERS subset had most of the early relapses [0 to 2.5 years, HR 6.53; p < 0.0001] especially in node negative tumors and showed minimal response to neoadjuvant letrozole. These findings were qualitatively confirmed in a smaller independent cohort of tamoxifen-treated patients. Using different biomarkers provided similar results. Conclusions: Early relapses are highest in highly proliferative/low-ERS cancers, in particular in node negative tumors. Relapses occurring after 5 years of adjuvant tamoxifen are highest among the highly-proliferative/high-ERS tumors although their risk of recurrence is modest in the first 5 years on tamoxifen. These tumors could be the best candidates for extended endocrine therapy

    Understanding the costs of investigating coliform and E. coli detections during routine drinking water quality monitoring

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    Bacteriological failure investigations are crucial in the provision of safe, clean drinking water as part of a process of quality assurance and continual improvement. However, the financial implications of investigating coliform and Escherichia coli failures during routine water quality monitoring are poorly understood in the industry. The investigations for 737 coliform and E. coli failures across five UK water companies were analysed in this paper. The principal components of investigation costs were staff hours worked, re-samples collected, transportation, and special investigatory activities related to the sample collection location. The average investigation costs ranged from £575 for a customer tap failure to £4,775 for a water treatment works finished water failure. These costs were compared to predictions for US utilities under the Revised Total Coliform Rule. Improved understanding of the financial and staffing implications of investigating bacteriological failures can be used to budget operational expenditures and justify increased funding for preventive strategies

    Vectorial capacity and vector control: reconsidering sensitivity to parameters for malaria elimination

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    Background: Major gains have been made in reducing malaria transmission in many parts of the world, principally by scaling-up coverage with long-lasting insecticidal nets and indoor residual spraying. Historically, choice of vector control intervention has been largely guided by a parameter sensitivity analysis of George Macdonald's theory of vectorial capacity that suggested prioritizing methods that kill adult mosquitoes. While this advice has been highly successful for transmission suppression, there is a need to revisit these arguments as policymakers in certain areas consider which combinations of interventions are required to eliminate malaria.Methods and Results: Using analytical solutions to updated equations for vectorial capacity we build on previous work to show that, while adult killing methods can be highly effective under many circumstances, other vector control methods are frequently required to fill effective coverage gaps. These can arise due to pre-existing or developing mosquito physiological and behavioral refractoriness but also due to additive changes in the relative importance of different vector species for transmission. Furthermore, the optimal combination of interventions will depend on the operational constraints and costs associated with reaching high coverage levels with each intervention.Conclusions: Reaching specific policy goals, such as elimination, in defined contexts requires increasingly non-generic advice from modelling. Our results emphasize the importance of measuring baseline epidemiology, intervention coverage, vector ecology and program operational constraints in predicting expected outcomes with different combinations of interventions.<br/
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