1,866 research outputs found
Can magnetar spin-down power extended emission in some short GRBs?
Extended emission gamma-ray bursts are a subset of the `short' class of burst
which exhibit an early time rebrightening of gamma emission in their light
curves. This extended emission arises just after the initial emission spike,
and can persist for up to hundreds of seconds after trigger. When their light
curves are overlaid, our sample of 14 extended emission bursts show a
remarkable uniformity in their evolution, strongly suggesting a common central
engine powering the emission. One potential central engine capable of this is a
highly magnetized, rapidly rotating neutron star, known as a magnetar.
Magnetars can be formed by two compact objects coallescing, a scenario which is
one of the leading progenitor models for short bursts in general. Assuming a
magnetar is formed, we gain a value for the magnetic field and late time spin
period for 9 of the extended emission bursts by fitting the magnetic dipole
spin-down model of Zhang & Meszaros (2001). Assuming the magnetic field is
constant, and the observed energy release during extended emission is entirely
due to the spin-down of this magnetar, we then derive the spin period at birth
for the sample. We find all birth spin periods are in good agreement with those
predicted for a newly born magnetar.Comment: 7 pages, 4 figures, 3 tables. Accepted for publication in MNRA
A Wolf in Sheep's Clothing? Patients' and Healthcare Professionals' Perceptions of Oxygen Therapy: An Interpretative Phenomenological Analysis.
Background: Despite emerging evidence and guidelines, poor prescribing and administration of oxygen therapy persists. This study aimed to explore healthcare professionals’ (HCPs) and patients’ perceptions of oxygen. Design: Semi-structured interviews with 28 patients and 34 HCPs. Findings: Three master themes uncovered: oxygen as a panacea, the burden of oxygen, and antecedents to beliefs. Patients used oxygen for breathlessness and as an enabler; they were grateful to oxygen and accepted it as part of the disease. HCPs used oxygen because it helps patients; it works; and it makes HCPs feel better. But oxygen is not benign and a burden is evident with potential antecedents to beliefs revealed. Summary: The findings suggest that a set of fixed beliefs regarding oxygen exist, influenced by several impacting factors. The perception that oxygen is a universal remedy presides, but is, at times, contradictory. These findings will raise awareness of entrenched cultures, influence future educational and research strategies, and inform policy
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Testing Browsertrix at the National Library of New Zealand
Presentation for the IIPC General Assembly and Web Archiving Conference held on May 10-12, 2023 in Hilversum, Netherlands. This presentation discusses the use of the newly developed Browsertrix crawler to capture sites and content at the National Library of New Zealand. It illustrates how Browsertrix has allowed for the capture of platforms and embedded media that previously created difficulties
Prognostic Accuracy of Antenatal Doppler Ultrasound Measures in Predicting Adverse Perinatal Outcomes for Pregnancies Complicated by Diabetes: A Systematic Review
OBJECTIVE: This study aimed to assess the prognostic accuracies of Doppler ultrasound measures in predicting adverse perinatal outcomes for pregnancies complicated with preexisting or gestational diabetes mellitus. DATA SOURCES: An online database search of MEDLINE, Cochrane, Embase, CINAHL, Scopus, and Emcare from inception to April 2022 was conducted.
STUDY ELIGIBILITY CRITERIA: Studies reporting singleton, nonanomalous fetuses of women with either preexisting (type 1 or 2 diabetes mellitus) or gestational diabetes mellitus during pregnancy were included. In addition, the included studies assessed cerebroplacental ratio and middle cerebral artery and/or umbilical artery pulsatility index in the prediction of either: preterm birth, cesarean delivery for fetal distress, APGAR (Appearance, Pulse, Grimace, Activity, and Respiration) score 24 hours), acute respiratory distress syndrome, jaundice, hypoglycemia, hypocalcemia, or neonatal death.
METHODS: The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed and 610 articles were identified, of which 15 were included. Two authors independently extracted prognostic data from each article and assessed the study applicability and risk of bias using the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) scoring criteria.
RESULTS: A total of 15 studies were included in the review and comprised prospective (n=10; 66%) and retrospective (n=5; 33%) cohorts. Sensitivity and positive predictive values varied widely across each Doppler measurement. Umbilical artery sensitivities were higher than those of cerebroplacental ratio and middle cerebral artery for hypoglycemia, jaundice, neonatal intensive care unit admission, respiratory distress, and preterm birth. Cerebroplacental ratio was the most reported index test; however, prognostic accuracy was worse than that of umbilical artery and middle cerebral artery Doppler across all adverse perinatal outcomes. Significant risk of bias was present in 14 (94%) studies, with substantial heterogeneity observed across studies in terms of study design and outcomes assessed.
CONCLUSION: Abnormal umbilical artery pulsatility index may be of more clinical value in predicting adverse perinatal outcomes compared with cerebroplacental ratio and middle cerebral artery pulsatility index in diabetic pregnancies. Further evaluation of umbilical artery Doppler measurements in diabetic pregnancies using standardized variables across studies is required for broader clinical application. The significant association between abnormal Doppler measurement and hypoglycemia may warrant further investigation
Is information enough? User responses to seasonal climate forecasts in Southern Africa
Since the mid-1980s, long-lead climate forecasts have been developed and used to predict the onset of El Niño events and their impact on climate variability. Advances in the observational and theoretical understanding of El Niño and the Southern Oscillation (ENSO) have contributed to improved seasonal forecasts, with lead times of up to one year. As the ability to forecast climate variability improves, the potential social and economic applications of forecasts have become an issue of great interest. There is widespread optimism that the availability and dissemination of climate forecasts can provide much-needed information that will inevitably reduce the losses and damages attributed to climate variability. However, this study indicates that it is not only the availability of information that matters, but also the end-users capacity to act upon it.
This report discusses user responses to seasonal climate forecasts in southern Africa, with an emphasis on small-scale farmers in Namibia and Tanzania. The study examines if and how farmers received, used, and perceived the forecasts in the 1997/98 agricultural season. The report also includes a summary of a workshop on user responses to seasonal forecasts in southern Africa, organized as part of the larger project. The participants in this workshop discussed some of the bottlenecks and constraints in terms of both forecast dissemination and user responses in various branches of the agricultural sector. A comparison of case studies across southern Africa revealed that there were differences in both dissemination strategies and in the capacity to respond to extreme events. Nevertheless, it was clear that improvements in forecast dissemination coupled with improved capacity to respond to the forecasts could yield net benefits for agricultural production in southern Africa.
Case studies in Namibia and Tanzania were undertaken to capture the extent to which seasonal forecasts reached “end users” in the agricultural sector. The responses indicate both the possibilities and limitations related to climate forecasts as a means of reducing rural vulnerability to climate variability. Interviews were also conducted with national and regional agricultural and food security institutions in Namibia, Tanzania, and Zimbabwe. Institutions included government agencies, farmer organizations, research institutions, and private companies. Participation in two of the three SARCOF meetings held during the 1997/98 season provided insight into forecast development and dissemination, as well as into the emerging dialog between forecasters and users.
The surveys revealed two main trends. First, there is a need to expand dissemination. Second, there is a pressing need to improve capacity for using the forecasts. In terms of dissemination, the surveys showed that less than half of the small-scale farmers interviewed actually received the pre-season forecasts, and fewer heard the mid-season updates. Moreover, what forecasts were received were often confused with other reports stemming from the coincidental occurrence of a very strong El Niño phenomenon. One reason so few small-scale farmers received the forecasts is that they have not been directly targeted as end-users.
While dissemination efforts have clearly been inadequate, they do not appear to be as consequential as problems related to the capacity of small-scale farmers to respond to the forecasts. Unless farmers have the ability to correctly interpret the forecasts, and the capacity to take action based upon the information, the forecasts will remain underutilized. Constraints to the capacity to respond to climate forecasts lie in economic and social structures, rather than uniquely in a lack of information. Access to credit, seeds, fertilizers, draft power, and markets shapes the ability of farmers to respond to climate information.
In the wake of the 1997/98 El Niño event, there is a need to critically reflect upon the potential benefits of seasonal climate forecasts. Responses to present-day climate variability form the cornerstone for adapting to future climate changes. In anticipation of potential changes in the frequency and/or magnitude of extreme events associated with global climate change, there is clearly a need for improved seasonal forecasts and better information dissemination. Nevertheless, the results of this study caution against a misplaced emphasis on improving the accuracy of forecasts at the expense of increasing the flexibility of farmers to adapt. Instead, the provision of information must be tied to enhanced response or adaptation options.
Climate forecasts have the potential to increase food security in southern Africa. However, to realize the full extent of potential benefits, response strategies should be strategically developed alongside dissemination strategies targeted at small-scale farmers. Moreover, this study points to a need to examine how economic changes taking place in southern Africa enhance or constrain this flexibility. Seasonal climate forecasts can serve as more than a tool for emergency management of food aid. Addressing the economic constraints to the use of seasonal climate forecasts could place farmers in a position where they could actually act upon the information. Information alone is not enough, but combined with increased attention to response strategies, seasonal climate forecasts can serve as a valuable tool for farmers in southern Africa.Acknowledgment
The authors would like to acknowledge the support and contributions of the many people who assisted us in this project. We are grateful to Arne Dalfelt of the World Bank for helping us to make this project a reality, and for supporting CICERO’s longer-term research on climate change and variability in Africa. We would also like to thank Mike Harrison, Macol Stewart and the participants in the SARCOF meetings for encouraging and facilitating this research.
For the field research in Namibia, we would like to express our thanks to Luis de Pisano, Peter Hutchinson, Kintinu Sageus, Gert van Eeden, Dave Cole, Mary Seely, Chris Morry, Franz Oberprieler, John le Roux, Paul Strydom, Barbara de Bruine, Gert Grobler, Ronnie Bornman, Cobus Franken, Pieter Hugo, and the others who took the time to share their views with us on seasonal climate forecasts and their potential use in Namibia. We would also like to thank Fiina Shimaneni, Otto Kamwi, and colleagues at the Multidisciplinary Research Center at the University of Namibia for their assistance with the field surveys. We are grateful to Sylvi Endresen for helping us to coordinate this field research, and to Jürgen Hoffman for his support, assistance, and enthusiasm for the project.
The fieldwork in Tanzania would not have been possible without the assistance and cooperation of colleagues at Sokoine University, including Nganga Kihupi and Winifrida Rwamugira. We are also grateful to Bahari Mumali, James Ngana, Burhani Nyenzi, Mr. Kalinga, Juvenal R.L. Kisanga, S.A. Muro, and F.E. Mahua for their generous time.
In Zimbabwe, we would like to thank Leonard Unganai, Brad Garanganga, Eliot Vhurumuku, C.H. Matarira, Stephen Crawford, Saskia van Osterhout, Marufu.C. Zinyowera, Sylvester Tsikisayi, Amos Makarau, Mr. Malusalila, Amus Chitambira, Micael Negusse, Roland Keth, and Veronica Mutikana for taking time to discuss the forecasts and their implications with us.
We are grateful to the participants in the Dar es Salaam Workshop on User Responses to Seasonal Forecasts in Southern Africa, for sharing their insights and contributing to a productive exchange of research findings and ideas. In addition to the authors and collaborators mentioned above, participants include Anna Bartman, Roger Blench, Louise Bohn, Tharsis Herea, Amin Bakari Iddi, Maynard Lugenja, Jennifer Phillips, Anne Thomson, and Coleen Vogel.
Finally, we would like to thank Lynn Nygård, Bård Romstad, and Tone Veiby for editorial assistance with this report
Novel type of phase transition in a system of self-driven particles
A simple model with a novel type of dynamics is introduced in order to
investigate the emergence of self-ordered motion in systems of particles with
biologically motivated interaction. In our model particles are driven with a
constant absolute velocity and at each time step assume the average direction
of motion of the particles in their neighborhood with some random perturbation
() added. We present numerical evidence that this model results in a
kinetic phase transition from no transport (zero average velocity, ) to finite net transport through spontaneous symmetry breaking of the
rotational symmetry. The transition is continuous since is
found to scale as with
Parameter Estimation for a Model With Both Imperfect Test and Repair
We describe estimation of the parameters of a
manufacturing test and repair model using data available
from that test. The model allows imperfect testing and
imperfect repair. The principal problem that we address
is of parameter identification, given insufficient data, that we address by making conservative assumptions on the
property being measured and the associated parameter
values. Several cases of commonly occurring test types, in
the manufacture of electronic products, are considered
Relationship between gender, physical activity, screen time, body mass index and wellbeing in Irish children from social-disadvantage
Research has shown that childhood physical activity participation has a positive relationship with markers of wellbeing, such as self-esteem and quality of life, and physical activity participation may serve as protective mechanism against some mental illnesses including depression. The aim of the current study was to examine the relationship between gender, physical activity, screen time, body mass index and wellbeing in Irish school children (N = 705; mean age: 8.74 ± 0.52 years) from social disadvantage. In Northern Ireland, schools included in the 2010 Multiple Deprivation Measure (NIMDM) were invited to participate. Schools included for participation in the Republic of Ireland were from the Delivering Equality of Opportunity in Schools (DEIS) index. Data gathered included accelerometry (physical activity), self-report (screen time and wellbeing), and anthropometric measurements. Physical activity was objectively measured during eight consecutive days using Actigraph GT1M and GT3X devices, using stringent accelerometer protocol. Screen time activities were derived using questions adapted from the Health Promotion Agencies National Children’s Survey in Northern Ireland. The KIDSCREEN-27 is a health-related quality of life measurement, and this tool was used by participants to self-report their health and wellbeing. Results suggest that boys accumulated more minutes of daily screen time than girls, however, boys were more physically active when compared to girls. Wellbeing scores for gender showed inverse associations with daily screen time. Standard multiple regression revealed that gender, physical activity, screen time and body mass index (combined) explained little variance in the prediction of wellbeing. Results indicate the importance of gender-based considerations for physical activity and screen time with children from social disadvantage. The inverse relationship found between overall screen time and wellbeing will help guide future healthy lifestyle interventions for Irish children of low-income communities
Assessing the Impact of Space School UK
Space School UK (SSUK) is a series of summer residential programmes for
secondary school aged students, held at the University of Leicester over 3
weeks each year. Each programme involves space-related activities run by a team
of mentors - currently including university students, graduates, teachers and
young professionals associated with the space sector - all of whom attended
SSUK as students themselves. It includes the 6-day Space School UK and the
8-day Senior Space School UK (collectively SSUK) which are for 13-15 and 16-18
year olds respectively. This paper seeks to evaluate and present the benefits
of SSUK to individuals who participate in the programme, organisations involved
in the running of SSUK, and to highlight and promote these benefits to the
wider UK and global space community. We also address which facets of SSUK make
for such an engaging and encouraging experience for the students, that are
missing from students' traditional education. We seek to show how SSUK acts as
an excellent example of how to bridge the gap between secondary and tertiary
space education. Through an analysis of our alumni survey results, we show that
attending SSUK has a significant impact on career choices and prepares students
for Higher Education, regardless of background. Some groups, such as women, and
those from non-selective schools, reported a higher impact in some of these
areas than others. Metrics such as skills learned, goals achieved, alongside
knowledge of careers and Higher Education possibilities are discussed for
various demographics.Comment: 7 pages, 12 figures, published in Proceedings of the 3rd Symposium on
Space Educational Activities (2019
Associations of snoring frequency and intensity in pregnancy with time‐to‐delivery
BackgroundSleep‐disordered breathing (SDB) is linked to adverse pregnancy outcomes. However, little is known about the association of SDB with timing of delivery. We examined the association of snoring frequency, a key SDB marker, and snoring intensity, a correlate of SDB severity, with time‐to‐delivery among a cohort of pregnant women.MethodsIn this prospective cohort study, 1483 third trimester pregnant women were recruited from the University of Michigan prenatal clinics. Women completed a questionnaire about their sleep, and demographic and pregnancy information was abstracted from medical charts. After exclusion of those with hypertension or diabetes, 954 women were classified into two groups by their snoring onset timing, chronic or pregnancy‐onset. Within each of these groups, women were divided into four groups based on their snoring frequency and intensity: non‐snorers; infrequent‐quiet; frequent‐quiet; or frequent‐loud snorers. Cox proportional hazard regression models were used to investigate the association between snoring frequency and intensity and time‐to‐delivery, adjusting for maternal characteristics.ResultsChronic snoring was reported by half of the pregnant women, and of those, 7% were frequent‐loud snorers. Deliveries before 38 weeks’ gestation are completed occurred among 25% of women with chronic, frequent‐loud snoring. Compared with pre‐pregnancy non‐snorers, women with chronic frequent‐loud snoring had an increased hazard ratio for delivery (adjusted hazard ratio 1.60, 95% confidence interval 1.04, 2.45).ConclusionsSnoring frequency and intensity is associated with time‐to‐delivery in women absent of hypertension or diabetes. Frequent‐loud snoring may have a clinical utility to identify otherwise low‐risk women who are likely to deliver earlier.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146650/1/ppe12511.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146650/2/ppe12511_am.pd
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