170 research outputs found
The Snuffbox Arteriovenous Fistula for Vascular Access
AbstractObjectives to determine the applicability, patency rates and factors influencing patency of snuffbox arteriovenous fistulae for haemodialysis access. Design retrospective non-randomised study. Materials and methods patency was determined by reference to an ongoing database and dialysis records of 645 vascular access procedures between 1985 and 1997, including 210 snuffbox fistulae in 201 patients. Results snuffbox fistulae comprised 189/376 (50%) primary procedures. Records of 208 snuffbox fistulae were available for patency analysis by the life-table method. Twenty-two (11%) thrombosed within 24 hours of operation. After six weeks 80% were used for dialysis. Cumulative patency was 65% at 1 year and 45% at 5 years. After thrombosis of snuffbox fistulae, ipsilateral wrist fistulae could be constructed in 45%. Fistula patency was significantly better in men than women (p<0.001) and for left- than right-sided fistulae (p<0.001). Diabetes, age >70 years, and the prior commencement of haemodialysis did not significantly affect fistula survival. Conclusions the snuffbox AV fistula gives a long segment of arterialised vein for needling and preserves proximal vessels. It is feasible in 50% of patients requiring primary access and has good long-term patency, especially in men. A more proximal fistula may be preferable in women with smaller vessels
Technology can sting when reality bites: Adolescents' frequent online coping is ineffective with momentary stress
The fact that youth widely engage with the online space in order to improve their emotional health has been lost amongst the debate surrounding adolescents' technology use and associated well-being. Two studies focused on adolescents' use of technology to cope with stressors in daily life. Focus groups (Study 1; n = 16) indicated that youth readily identify using technology to cope and perceive it as helpful for emotional relief. Experience sampling participants (Study 2; n = 156) completed a baseline assessment of online coping and mental health, and one week of reports, five times daily, on their technology use, stress, and emotions. Multilevel regression results indicated that across their daily lives, youth who widely endorsed using online strategies to cope responded more negatively to stressors and displayed difficulties in recovering from worry and jealousy. Results held even controlling for use of technology, typical number of stressors, and mental health. Findings highlight the potential shortcomings and comorbid vulnerabilities for youth who frequently turn to the online environment to seek support, information, or distraction
The contribution of cattle urine and dung to nitrous oxide emissions: Quantification of country specific emission factors and implications for national inventories
Publication history: Accepted - 10 April 2018; Published online - 24 April 2018.Urine patches and dung pats from grazing livestock create hotspots for production and emission of the greenhouse
gas, nitrous oxide (N2O), and represent a large proportion of total N2O emissions in many national agricultural
greenhouse gas inventories. As such, there is much interest in developing country specific N2O emission
factors (EFs) for excretal nitrogen (EF3, pasture, range and paddock) deposited during gazing. The aims of this
study were to generate separate N2O emissions data for cattle derived urine and dung, to provide an evidence
base for the generation of a country specific EF for the UK from this nitrogen source. The experiments were
also designed to determine the effects of site and timing of application on emissions, and the efficacy of the nitrification
inhibitor, dicyandiamide (DCD) on N2O losses. This co-ordinated set of 15 plot-scale, year-long field experiments
using static chambers was conducted at five grassland sites, typical of the soil and climatic zones of
grazed grassland in the UK. We show that the average urine and dung N2O EFs were 0.69% and 0.19%, respectively,
resulting in a combined excretal N2O EF (EF3), of 0.49%, which is b25% of the IPCC default EF3 for excretal
returns from grazing cattle. Regression analysis suggests that urineN2O EFs were controlledmore by composition
than was the case for dung, whilst dung N2O EFs were more related to soil and environmental factors. The urine
N2O EF was significantly greater from the site in SW England, and significantly greater from the early grazing season urine application than later applications. Dycandiamide reduced the N2O EF fromurine patches by an average
of 46%. The significantly lower excretal EF3 than the IPCC default has implications for the UK's national inventory
and for subsequent carbon footprinting of UK ruminant livestock productsThe authors are grateful to the UK Department for Environment,
Food and Rural Affairs (Defra), the Department of Agriculture and Rural
Development (now the Department of Agriculture, Environment and
Rural Affairs) in Northern Ireland, and the Scottish Government and
the Welsh Government for financial support via the InveN2Ory project
(AC0116). The work by Rothamsted Research was additionally supported
by the Biotechnology and Biological Sciences Research Council
(BBS/E/C/000I0320). We would also like to thank Jon Moorby (IBERS,
Wales, UK), Reading University, SRUC (Scotland, UK) and Conrad Ferris
(AFBI, Northern Ireland, UK), for provision of cattle urine and dung
Customer emotions in service failure and recovery encounters
Emotions play a significant role in the workplace, and considerable attention has been given to the study of employee emotions. Customers also play a central function in organizations, but much less is known about customer emotions. This chapter reviews the growing literature on customer emotions in employee–customer interfaces with a focus on service failure and recovery encounters, where emotions are heightened. It highlights emerging themes and key findings, addresses the measurement, modeling, and management of customer emotions, and identifies future research streams. Attention is given to emotional contagion, relationships between affective and cognitive processes, customer anger, customer rage, and individual differences
Star clusters near and far; tracing star formation across cosmic time
© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00690-x.Star clusters are fundamental units of stellar feedback and unique tracers of their host galactic properties. In this review, we will first focus on their constituents, i.e.\ detailed insight into their stellar populations and their surrounding ionised, warm, neutral, and molecular gas. We, then, move beyond the Local Group to review star cluster populations at various evolutionary stages, and in diverse galactic environmental conditions accessible in the local Universe. At high redshift, where conditions for cluster formation and evolution are more extreme, we are only able to observe the integrated light of a handful of objects that we believe will become globular clusters. We therefore discuss how numerical and analytical methods, informed by the observed properties of cluster populations in the local Universe, are used to develop sophisticated simulations potentially capable of disentangling the genetic map of galaxy formation and assembly that is carried by globular cluster populations.Peer reviewedFinal Accepted Versio
All-sky search for long-duration gravitational wave transients with initial LIGO
We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society
All-sky search for long-duration gravitational wave transients with initial LIGO
We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society
Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model
We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society
Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO-Virgo Run O3b
We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC-2020 March 27 17:00 UTC). We conduct two independent searches: A generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate. © 2022. The Author(s). Published by the American Astronomical Society
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