130 research outputs found

    Why Extension-Based Proofs Fail

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    We introduce extension-based proofs, a class of impossibility proofs that includes valency arguments. They are modelled as an interaction between a prover and a protocol. Using proofs based on combinatorial topology, it has been shown that it is impossible to deterministically solve k-set agreement among n > k > 1 processes in a wait-free manner in certain asynchronous models. However, it was unknown whether proofs based on simpler techniques were possible. We show that this impossibility result cannot be obtained for one of these models by an extension-based proof and, hence, extension-based proofs are limited in power.Comment: This version of the paper is for the NIS model. Previous versions of the paper are for the NIIS mode

    Bridging the biodiversity data gaps: Recommendations to meet users’ data needs

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    A strong case has been made for freely available, high quality data on species occurrence, in order to track changes in biodiversity. However, one of the main issues surrounding the provision of such data is that sources vary in quality, scope, and accuracy. Therefore publishers of such data must face the challenge of maximizing quality, utility and breadth of data coverage, in order to make such data useful to users. Here, we report a number of recommendations that stem from a content need assessment survey conducted by the Global Biodiversity Information Facility (GBIF). Through this survey, we aimed to distil the main user needs regarding biodiversity data. We find a broad range of recommendations from the survey respondents, principally concerning issues such as data quality, bias, and coverage, and extending ease of access. We recommend a candidate set of actions for the GBIF that fall into three classes: 1) addressing data gaps, data volume, and data quality, 2) aggregating new kinds of data for new applications, and 3) promoting ease-of-use and providing incentives for wider use. Addressing the challenge of providing high quality primary biodiversity data can potentially serve the needs of many international biodiversity initiatives, including the new 2020 biodiversity targets of the Convention on Biological Diversity, the emerging global biodiversity observation network (GEO BON), and the new Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES)

    Red Supergiant Candidates for Multimessenger Monitoring of the Next Galactic Supernova

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    We compile a catalog of 598 highly probable and 79 likely red supergiants (RSGs) of the Milky Way, which represents the largest list of Galactic RSG candidates to date. We matched distances measured by Gaia DR3, 2MASS photometry, and a 3D Galactic dust map to obtain luminous bright late-type stars. Determining the stars' bolometric luminosities and effective temperatures, we compared to Geneva stellar evolution tracks to determine likely RSG candidates, and quantified contamination using a catalog of Galactic AGB in the same luminosity-temperature space. We add details for common or interesting characteristics of RSG, such as multi-star system membership, variability, and classification as a runaway. As potential future core-collapse supernova (SN) progenitors, we studied the ability of the catalog to inform the Supernova Early Warning System (SNEWS) coincidence network made to automate pointing, and show that for 3D position estimates made possible by neutrinos, the number of progenitor candidates can be significantly reduced, improving our ability to observe the progenitor pre-explosion and the early phases of the core-collapse supernova.Comment: 21 pages, 10 figures, 5 table. Comments welcom

    Factors predicting amoxicillin prescribing in primary care among children: a cohort study

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    Background: Antibiotic prescribing during childhood contributes to antimicrobial resistance, which is a major public health concern. Antibiotics are most commonly prescribed to children for respiratory tract infections (RTI). / Aim: To identify factors associated with amoxicillin prescribing and RTI consultation attendance in primary care in young children. / Design and Setting: Cohort study in Bradford with data from pregnancy to age 24-months collected between 2007-2013, linked to electronic primary care and air pollution data. / Methods: We calculated amoxicillin prescribing rates/1,000 child-years, and fitted mixed-effects logistic regression models, with general practice (GP) surgery as the random effect, to establish risk factors for amoxicillin prescribing and RTI consultation during the first two years. / Results: Among 2,493 children, the amoxicillin prescribing rate was 710/1,000 child-years during the first year (95% CI: 677-744) and 780/1,000 (745-816) during the second year. Odds of amoxicillin prescribing during year one were higher for infants who were male (adjusted OR 1.4 (1.1-1.6)), socio-economically deprived (1.4 (1.0-1.9)), and with a Pakistani ethnic background (1.4 (1.1-1.9)). Odds of amoxicillin prescribing during the second year were higher for infants with a Pakistani ethnic background (1.5 (1.1-2.0)/1.6 (1.2-2.0)) and pre-/early-term infants (1.2 (1.0-1.5)). Additional risk factors included caesarean delivery, congenital anomalies, household overcrowding, birth season, and formal childcare attendance. GP surgery-level variation explained 7-9% of variation in amoxicillin prescribing. / Conclusions: Socio-economic status and ethnic background are strongly associated with amoxicillin prescribing and RTI consultations during childhood. Interventions reducing RTI spread in household and childcare settings may reduce antibiotic prescribing in primary care

    Capacity precommitment as a barrier to entry: a Bertrand-Edgeworth approach

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    This paper considers the role of capacity as a strategic entry deterrent for a game in which the incumbent and entrant sequentially precommit to capacity levels before competing in price, possibly using mixed strategies. Depending on the magnitudes of the fixed set-up cost, the cost of capacity, and the relative costs of production, the model produces a wide spectrum of equilibrium behaviors, including some not previously suggested in the literature. Interesting deterrence effects occur because firms need time to build. In contrast to much previous work, the incumbent may hold idle capacity when entry is deterred.Competition

    One Tube Does Not Fit All: Parent Experiences and Decision-Making for Choosing a Nasogastric Tube or Gastrostomy for Their Child During Allogeneic Bone Marrow Transplant

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    Background: Children undergoing bone marrow transplant (BMT) are at risk of developing malnutrition. A feeding tube becomes a requirement for most children to meet their nutritional and medication requirements. Two tubes are typically used: nasogastric tube (NGT) or gastrostomy. At the UK center where this study took place, parents are offered a choice between these tubes. Objective: This qualitative data collection in a mixed methods study explored why parents choose either tube and their experiences of using it. Methods: Parents participated in 2 semistructured interviews. First, on admission to explore why they chose either tube. Second, 1–2 months postdischarge to explore their experience of using the tube. Interviews took place over 18 months. Transcripts were thematically analyzed. Results: Sixteen parents whose child had an NGT, 17 a gastrostomy, were interviewed. Choice was experienced across a continuum of difficulty and freedom. Many parents deferred to the expertise of professionals; others felt they were the experts in their child. Influential factors in decision-making included expected duration of need, the child’s age and activity, cosmetic differences, balancing gastrostomy surgery against NGT dislodgement, lay advice, healthcare professionals’ recommendations and prior tube feeding experiences. Conclusions: Parents valued choice appreciating 1 feeding tube might not suit every child. Implications for Practice: Choice of a gastrostomy or NGT should be offered to children prior to BMT. What is Foundational: Parents navigate a complex decision-making process when choosing a feeding tube for their child. Healthcare professionals can facilitate informed decision-making through collaborative discussions, inclusion of peer support, and provision of balanced information

    Longitudinal cohort study of the impact of specialist cancer services for teenagers and young adults on quality of life: outcomes from the BRIGHTLIGHT study.

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    OBJECTIVES: In England, healthcare policy advocates specialised age-appropriate services for teenagers and young adults (TYA), those aged 13 to 24 years at diagnosis. Specialist Principal Treatment Centres (PTC) provide enhanced TYA age-specific care, although many still receive care in adult or children's cancer services. We present the first prospective structured analysis of quality of life (QOL) associated with the amount of care received in a TYA-PTC DESIGN: Longitudinal cohort study. SETTING: Hospitals delivering inpatient cancer care in England. PARTICIPANTS: 1114 young people aged 13 to 24 years newly diagnosed with cancer. INTERVENTION: Exposure to the TYA-PTC defined as patients receiving NO-TYA-PTC care with those receiving ALL-TYA-PTC and SOME-TYA-PTC care. PRIMARY OUTCOME: Quality of life measured at five time points: 6, 12, 18, 24 and 36 months after diagnosis. RESULTS: Group mean total QOL improved over time for all patients, but for those receiving NO-TYA-PTC was an average of 5.63 points higher (95% CI 2.77 to 8.49) than in young people receiving SOME-TYA-PTC care, and 4·17 points higher (95% CI 1.07 to 7.28) compared with ALL-TYA-PTC care. Differences were greatest 6 months after diagnosis, reduced over time and did not meet the 8-point level that is proposed to be clinically significant. Young people receiving NO-TYA-PTC care were more likely to have been offered a choice of place of care, be older, from more deprived areas, in work and have less severe disease. However, analyses adjusting for confounding factors did not explain the differences between TYA groups. CONCLUSIONS: Receipt of some or all care in a TYA-PTC was associated with lower QOL shortly after cancer diagnosis. The NO-TYA-PTC group had higher QOL 3 years after diagnosis, however those receiving all or some care in a TYA-PTC experienced more rapid QOL improvements. Receipt of some care in a TYA-PTC requires further study.This paper presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research Programme (Grant Reference Number RP-PG-1209-10013). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health. The BRIGHTLIGHT Team acknowledges the support of the NIHR, through the Cancer Research Network. LAF and LH are funded by Teenage Cancer Trust, DPS holds research grant funding from Teenage Cancer Trust, and RR was (in part) supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care (CLAHRC) North Thames at Bart’s Health NHS Trust. RMT is a National Institute for Health Research (NIHR) Senior Nurse Research Leader. The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. None of the funding bodies have been involved with study concept, design or decision to submit the manuscript. JA-G was subsidised by the Ramon & Cajal programme operated by the Ministry of Economy and Business (RYC-2016-19353), and the European Social Fund

    Factors predicting amoxicillin prescribing in primary care among children: a cohort study

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    Background: Antibiotic prescribing during childhood contributes to antimicrobial resistance, which is a major public health concern. Antibiotics are most commonly prescribed to children for respiratory tract infections (RTI). Aim: To identify factors associated with amoxicillin prescribing and RTI consultation attendance in primary care in young children. Design and Setting: Cohort study in Bradford with data from pregnancy to age 24-months collected between 2007-2013, linked to electronic primary care and air pollution data. Methods: We calculated amoxicillin prescribing rates/1,000 child-years, and fitted mixed-effects logistic regression models, with general practice (GP) surgery as the random effect, to establish risk factors for amoxicillin prescribing and RTI consultation during the first two years. Results: Among 2,493 children, the amoxicillin prescribing rate was 710/1,000 child-years during the first year (95% CI: 677-744) and 780/1,000 (745-816) during the second year. Odds of amoxicillin prescribing during year one were higher for infants who were male (adjusted OR 1.4 (1.1-1.6)), socio-economically deprived (1.4 (1.0-1.9)), and with a Pakistani ethnic background (1.4 (1.1-1.9)). Odds of amoxicillin prescribing during the second year were higher for infants with a Pakistani ethnic background (1.5 (1.1-2.0)/1.6 (1.2-2.0)) and pre-/early-term infants (1.2 (1.0-1.5)). Additional risk factors included caesarean delivery, congenital anomalies, household overcrowding, birth season, and formal childcare attendance. GP surgery-level variation explained 7-9% of variation in amoxicillin prescribing. Conclusions: Socio-economic status and ethnic background are strongly associated with amoxicillin prescribing and RTI consultations during childhood. Interventions reducing RTI spread in household and childcare settings may reduce antibiotic prescribing in primary care.</jats:p

    Risk Factors and Spatial Distribution of Schistosoma mansoni Infection among Primary School Children in Mbita District, Western Kenya

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    Background:An increasing risk of Schistosoma mansoni infection has been observed around Lake Victoria, western Kenya since the 1970s. Understanding local transmission dynamics of schistosomiasis is crucial in curtailing increased risk of infection.Methodology/Principal Findings:We carried out a cross sectional study on a population of 310 children from eight primary schools. Overall, a total of 238 (76.8%) children were infected with S. mansoni, while seven (2.3%) had S. haematobium. The prevalence of hookworm, Trichuris trichiura and Ascaris lumbricoides were 6.1%, 5.2% and 2.3%, respectively. Plasmodium falciparum was the only malaria parasite detected (12.0%). High local population density within a 1 km radius around houses was identified as a major independent risk factor of S. mansoni infection. A spatial cluster of high infection risk was detected around the Mbita causeway following adjustment for population density and other potential risk factors.Conclusions/Significance:Population density was shown to be a major factor fuelling schistosome infection while individual socio-economic factors appeared not to affect the infection risk. The high-risk cluster around the Mbita causeway may be explained by the construction of an artificial pathway that may cause increased numbers of S. mansoni host snails through obstruction of the waterway. This construction may have, therefore, a significant negative impact on the health of the local population, especially school-aged children who frequently come in contact with lake water
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