173 research outputs found

    The stability of the optical flux variation gradient for 3C120

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    New BB- and VV-band monitoring in 2014 −- 2015 reveals that the Seyfert 1 Galaxy, 3C120, has brightened by a magnitude of 1.41.4, compared to our campaign that took place in 2009 −- 2010. This allowed us to check for the debated luminosity and time-dependent color variations claimed for SDSS quasars. For our 3C120 data, we find that the B/VB/V flux ratio of the variable component in the bright epoch is indistinguishable from the faint one. We do not find any color variability on different timescales ranging from about 11 to 18001800 days. We suggest that the luminosity and time-dependent color variability is an artifact caused by analyzing the data in magnitudes instead of fluxes. The flux variation gradients of both epochs yield consistent estimates of the host galaxy contribution to our 7.5" aperture. These results confirm that the optical flux variation gradient method works well for Seyfert galaxies.Comment: 8 pages, 6 figures. Accepted for publication in section 4. Extragalactic astronomy of Astronomy and Astrophysics v2: Language-Editor Versio

    Direct non-medical costs double the total direct costs to patients undergoing cataract surgery in Zamfara state, Northern Nigeria: a case series.

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    BACKGROUND: Cost is frequently reported as a barrier to cataract surgery, but few studies have reported costs of accessing surgery in Africa. The purpose of this prospective, facility based study was to compare direct non-medical cost with total direct cost of cataract surgery to patients, and to assess how money was found to cover costs. METHODS: Participants were those aged 17 years and above attending their first post-operative visit after first eye, subsidised, day case cataract surgery. Systematic random sampling was used to select participants who were interviewed to obtain data on socio-demographic details, and on expenditure during the assessment visit, the surgical visit, and the first follow-up visit. Costs were a) direct medical costs (patients' costs for registration, investigations, surgery, medication), and b) direct non-medical costs (patients' and escorts' costs for transport, accommodation, meals). The source of funds to pay for the services received was also assessed. RESULTS: Almost two thirds (63%) of the 104 participants were men. The mean age of men was 64 (± 12.5) years, being 63 (± 12.9) years for women. All men were married and 35% of women were widows. 84% of men were household heads compared with 6% of women. The median total direct cost for all visits by all participants was N8,245 (US51),beinghigherformenthanwomen(N9,020;US51), being higher for men than women (N9,020; US56 and N7,620; US$47) (p < 0.09) respectively. Direct non-medical cost constituted 49% of total direct cost. 92% of participants had adequate money to pay, but 8% had to sell possessions to raise the money. 20% of unmarried women sold possessions or took out a loan. CONCLUSION: Despite the subsidy, cost is still likely to be a barrier to accessing cataract surgery, as the total direct costs represented at least 50 days income for 70% of the local population. Provision of transport would reduce direct non-medical costs

    Governance and Capacity to Manage Resilience of Health Systems: Towards a New Conceptual Framework.

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    The term resilience has dominated the discourse among health systems researchers since 2014 and the onset of the Ebola outbreak in West Africa. There is wide consensus that the global community has to help build more resilient health systems. But do we really know what resilience means, and do we all have the same vision of resilience? The present paper presents a new conceptual framework on governance of resilience based on systems thinking and complexity theories. In this paper, we see resilience of a health system as its capacity to absorb, adapt and transform when exposed to a shock such as a pandemic, natural disaster or armed conflict and still retain the same control over its structure and functions

    Assessment of the Effects of Active Immunisation against Respiratory Syncytial Virus (RSV) using Decision-Analytic Models: A Systematic Review with a Focus on Vaccination Strategies, Modelling Methods and Input Data

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    Background: Several vaccine and antibody candidates are currently in development for the prevention of lower respiratory tract infections caused by the respiratory syncytial virus (RSV). Methods: We searched MEDLINE, Embase, and SCOPUS and included model-based evaluations of RSV vaccinations. Two reviewers performed the selection, data extraction, and quality evaluation with EVIDEM. Cost-effectiveness (CE) estimates were converted to USpurchasingpowerparity(PPP),year2018values.Potentialeconomicandepidemiologicaloutcomesweresummarisedformaternal,infant,children,andelderlyvaccinations.ThePROSPEROidentifierisCRD42019122570.Results:Intotal,22model−basedstudieswerereviewed.Onaverage,apotential27US purchasing power parity (PPP), year 2018 values. Potential economic and epidemiological outcomes were summarised for maternal, infant, children, and elderly vaccinations. The PROSPERO identifier is CRD42019122570. Results: In total, 22 model-based studies were reviewed. On average, a potential 27% reduction in RSV hospitalisations in infants was projected for maternal vaccination and 50% for direct infant immunisation. The CE of maternal vaccination was US1766–5857 PPP 2018/disability-adjusted life-years (DALYs) for Global Alliance for Vaccines and Immunisation (Gavi)-eligible countries. For England, the maximum cost-effective price of maternal vaccination was estimated at $US81.5 PPP 2018. Infant vaccination was associated with higher CE ratios in low- and high-income settings. Vaccination of neonates born before the RSV season was the most cost effective in high-income settings. Higher values for vaccine effectiveness, duration of protection, and vaccine uptake increased the benefits. Due to indirect effects, the vaccination of school-age children and a cocooning strategy were effective alternatives to protect infants, and the vaccination of children aged < 5 years had a beneficial impact on the elderly. Conclusion: RSV vaccines with anticipated characteristics may reduce a sizeable proportion of the RSV burden. The results are subject to uncertainty because of the limited epidemiological and clinical data. Data on RSV incidence and hospitalisation risk for granular age strata should be prioritised to facilitate the evaluation of RSV interventions and decision making.Peer Reviewe

    The Interplay between Cytoskeleton and Calcium Dynamics

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    Cell motility is a complex cellular event that involves reorganization of cytoskeleton. This reorganization encompasses the transient polarization of the cell to facilitate the plasma membrane ruffling, a rearrangement of cortical actin cytoskeleton required for the development of cellular protrusions. It is known that extracellular Ca2+ influx is essential for cell migration and for the positive-feedback cycle that maintains leading-edge structures and ruffling activity. The aim of this review is to summarize our knowledge regarding the Ca2+-dependent signaling pathways, Ca2+ transporters and sensors involved in cell migration. Also, we show here reported evidences that support for a crosstalk between Ca2+ transport and the reorganization of the cytoskeleton required for cell migration. In this regard, we will analyze the role of store-operated Ca2+ entry (SOCE) as a modulator of cytoskeleton and cell migration, but also the modulation of this Ca2+ entry pathway by microtubules and the actin cytoskeleton. As a main conclusion, this review will show that data reported in the last years support a role for SOCE in shaping cytoskeleton, but at the same time, SOCE is strongly dependent on cytoskeletal proteins, in an interesting interplay between cytoskeleton and Ca2+ dynamics

    Regulation of Calcium Signaling by STIM1 and ORAI1

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    STIM1 and ORAI1 proteins are regulators of intracellular Ca2+ mobilization. This Ca2+ mobilization is essential to shape Ca2+ signaling in eukaryotic cells. STIM1 is a transmembrane protein located at the endoplasmic reticulum, where it acts as an intraluminal Ca2+ sensor. The transient drop of intraluminal Ca2+ concentration triggers STIM1 activation, which relocates to plasma membrane-endoplasmic reticulum junctions to bind and activate ORAI1, a plasma membrane Ca2+ channel. Thus, the Ca2+ influx pathway mediated by STIM1/ORAI1 is termed store-operated Ca2+ entry (SOCE). STIM and ORAI proteins are also involved in non-SOCE Ca2+ influx pathways, as we discuss here. In this chapter, we review the current knowledge regarding the role of SOCE, STIM1, and ORAI1 in cell signaling, with special focus on the modulation of the activity of kinases, phosphatases, and transcription factors that are strongly influenced by the extracellular Ca2+ influx mediated by these regulators

    A mixed methods protocol to evaluate the effect and cost-effectiveness of an Integrated electronic Diagnosis Approach (IeDA) for the management of childhood illnesses at primary health facilities in Burkina Faso.

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    BACKGROUND: Burkina Faso introduced the Integrated Management of Childhood Illnesses (IMCI) strategy in 2003. However, an evaluation conducted in 2013 found that only 28 % of children were assessed for three danger signs as recommended by IMCI, and only 15 % of children were correctly classified. About 30 % of children were correctly prescribed with an antibiotic for suspected pneumonia or oral rehydration salts (ORS) for diarrhoea, and 40 % were correctly referred. Recent advances in information and communication technologies (ICT) and use of electronic clinical protocols hold the potential to transform healthcare delivery in low-income countries. However, no evidence is available on the effect of ICT on adherence to IMCI. This paper describes the research protocol of a mixed methods study that aims to measure the effect of the Integrated electronic Diagnosis Approach innovation (an electronic IMCI protocol provided to nurses) in two regions of Burkina Faso. METHODS/DESIGN: The study combines a stepped-wedge trial, a realistic evaluation and an economic study in order to capture the effect of the innovation after its introduction on the level of adherence, cost and acceptability. DISCUSSION: The main challenge is to interconnect the three substudies. In integrating outcome, process and cost data, we focus on three key questions: (i) How does the effectiveness and the cost of the intervention vary by type of health worker and type of health centre? (ii) What is the impact of changes in the content, coverage and quality of the IeDA intervention on adherence and cost-effectiveness? (iii) What mechanisms of change (including costs) might explain the relationship between the IeDA intervention and adherence? TRIAL REGISTRATION: Clinicaltrials.gov, NCT02341469

    Comparative effectiveness of contact tracing interventions in the context of the COVID-19 pandemic: a systematic review

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    Contact tracing is a non-pharmaceutical intervention (NPI) widely used in the control of the COVID-19 pandemic. Its effectiveness may depend on a number of factors including the proportion of contacts traced, delays in tracing, the mode of contact tracing (e.g. forward, backward or bidirectional contact training), the types of contacts who are traced (e.g. contacts of index cases or contacts of contacts of index cases), or the setting where contacts are traced (e.g. the household or the workplace). We performed a systematic review of the evidence regarding the comparative effectiveness of contact tracing interventions. 78 studies were included in the review, 12 observational (ten ecological studies, one retrospective cohort study and one pre-post study with two patient cohorts) and 66 mathematical modelling studies. Based on the results from six of the 12 observational studies, contact tracing can be effective at controlling COVID-19. Two high quality ecological studies showed the incremental effectiveness of adding digital contact tracing to manual contact tracing. One ecological study of intermediate quality showed that increases in contact tracing were associated with a drop in COVID-19 mortality, and a pre-post study of acceptable quality showed that prompt contact tracing of contacts of COVID-19 case clusters / symptomatic individuals led to a reduction in the reproduction number R. Within the seven observational studies exploring the effectiveness of contact tracing in the context of the implementation of other non-pharmaceutical interventions, contact tracing was found to have an effect on COVID-19 epidemic control in two studies and not in the remaining five studies. However, a limitation in many of these studies is the lack of description of the extent of implementation of contact tracing interventions. Based on the results from the mathematical modelling studies, we identified the following highly effective policies: (1) manual contact tracing with high tracing coverage and either medium-term immunity, highly efficacious isolation/quarantine and/ or physical distancing (2) hybrid manual and digital contact tracing with high app adoption with highly effective isolation/ quarantine and social distancing, (3) secondary contact tracing, (4) eliminating contact tracing delays, (5) bidirectional contact tracing, (6) contact tracing with high coverage in reopening educational institutions. We also highlighted the role of social distancing to enhance the effectiveness of some of these interventions in the context of 2020 lockdown reopening. While limited, the evidence from observational studies shows a role for manual and digital contact tracing in controlling the COVID-19 epidemic. More empirical studies accounting for the extent of contact tracing implementation are required.Peer Reviewe

    Assessing COVID-19 through the lens of health systems' preparedness: time for a change.

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    The last months have left no-one in doubt that the COVID-19 pandemic is exerting enormous pressure on health systems around the world, bringing to light the sub-optimal resilience of even those classified as high-performing. This makes us re-think the extent to which we are using the appropriate metrics in evaluating health systems which, in the case of this pandemic, might have masked how unprepared some countries were. It also makes us reflect on the strength of our solidarity as a global community, as we observe that global health protection remains, as this pandemic shows, focused on protecting high income countries from public health threats originating in low and middle income countries. To change this course, and in times like this, all nations should come together under one umbrella to respond to the pandemic by sharing intellectual, human, and material resources. In order to work towards stronger and better prepared health systems, improved and resilience-relevant metrics are needed. Further, a new model of development assistance for health, one that is focused on stronger and more resilient health systems, should be the world's top priority

    Willingness to pay for cataract surgery is much lower than actual costs in Zamfara state, northern Nigeria.

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    PURPOSE: Direct medical and non-medical costs incurred by those undergoing subsidised cataract surgery at Gusau eye clinic, Zamfara state, were recently determined. The aim of this study was to assess the willingness to pay for cataract surgery among adults with severe visual impairment or blindness from cataract in rural Zamfara and to compare this to actual costs. METHODS: In three rural villages served by Gusau eye clinic, key informants helped identify 80 adults with bilateral severe visual impairment or blindness (<6/60), with cataract being the cause in at least one eye. The median amount participants were willing to pay for cataract surgery was determined. The proportion willing to pay actual costs of the (i) subsidised surgical fee (US18.5),(ii)averagenon−medicalexpenses(US18.5), (ii) average non-medical expenses (US25.2), and (iii) average total expenses (US51.2)atGusaueyeclinicwerecalculated.Whereparticipantswouldseekfundsforsurgerywasdetermined.RESULTS:Among80participants(3851.2) at Gusau eye clinic were calculated. Where participants would seek funds for surgery was determined. RESULTS: Among 80 participants (38% women), most (n = 73, 91%) were willing to pay something, ranging from <US1 to US186(medianUS186 (median US18.5, interquartile range 6.2-31.1). Approximately half of the participants (n = 41) were willing to pay US18.5(7818.5 (78% men), one-third (n = 26) were willing to pay US25.2 (77% men); and 11% (n = 9) were willing to pay US$51.2 (all men). Only six participants (8%) already had the money to pay; one quarter (n = 20) would need to sell possessions to raise the funds. CONCLUSION: Willingness to pay for cataract surgery among adults with operable cataract in rural Zamfara state is far lower than current costs of undergoing surgery. People who were widowed-most of whom were women-were willing to pay least. Further financial support is required for cataract surgery to be universally accessible
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