JURNAL AGROTEKNOLOGI
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Hard X-ray emission from a Compton scattering corona in large black hole mass tidal disruption events
No full textWe extend the relativistic time-dependent thin-disc TDE model to describe non-thermal (2-10 keV) X-ray emission produced by the Compton up-scattering of thermal disc photons by a compact electron corona, developing analytical and numerical models of the evolving non-thermal X-ray light curves. In the simplest cases, these X-ray light curves follow power-law profiles in time. We suggest that TDE discs act in many respects as scaled-up versions of XRB discs, and that such discs should undergo state transitions into harder accretion states. XRB state transitions typically occur when the disc luminosity becomes roughly one per cent of its Eddington value. We show that if the same is true for TDE discs then this, in turn, implies that TDEs with non-thermal X-ray spectra should come preferentially from large-mass black holes. The characteristic hard-state transition mass is MHS ≃ 2 × 107M⊙. Hence, subpopulations of thermal and non-thermal X-ray TDEs should come from systematically different black hole masses. We demonstrate that the known populations of thermal and non-thermal X-ray TDEs do indeed come from different distributions of black hole masses. The null-hypothesis of identical black hole mass distributions is rejected by a two-sample Anderson-Darling test with a p-value <0.01. Finally, we present a model for the X-ray rebrightening of TDEs at late times as they transition into the hard state. These models of evolving TDE light curves are the first to join both thermal and non-thermal X-ray components in a unified scenario
The labour market impacts of female internal migration: Evidence from the end of Apartheid
No full textWomen often migrate within developing countries for different reasons than men and female migrants tend to be very differently distributed across economic sectors as compared to male migrants. This paper provides some of the first evidence on the labour market impacts of female internal migration, examining effects in both the productive and household sectors. I merge large sample migration data from South African censuses with detailed labour force survey data, and exploit substantial time-variation in female migrant inflows into over 200 districts. To identify the causal effects of migration on labour market outcomes, I make use of the unique history of South Africa to construct a plausibly exogenous shift-share instrument for female migrant concentration based on earlier male migration flows from reserves during the Apartheid period. I firstly find that this migration increases the employment and hours worked of high-skilled women (but not men). I demonstrate that this effect is driven by substitution in household work as many female migrants find work as domestic helpers. I also find that female migration leads to a (short-term) reduction in the employment of low-skilled female non-migrants suggesting an increase in competition at the bottom of the economic ladder
Lung simulation to support non-invasive pulmonary blood flow measurement in acute respiratory distress syndrome in animals
No full textPatients undergoing mechanical lung ventilation are at risk of lung injury. A noninvasive bedside lung monitor may benefit these patients. The Inspired Sinewave Test (IST) can measure cardio-pulmonary parameters noninvasively. We propose a lung simulation to improve the measurement of pulmonary blood flow using IST. The new method was applied to 12 pigs’ data before lung injury (control) and after lung injury (ARDS model). Results using the lung simulation shown improvements in correlation in both simulated data (R 2 increased from 0.98 to 1) and pigs’ data (R 2 increased from <0.001 to 0.26). Paired blood flow measurements were performed by both the IST (noninvasive) and thermodilution (invasive). In the control group, the bias of the two methods was negligible (0.02L/min), and the limit of agreement was from -1.20 to 1.18 L/min. The bias was -0.68 L/min in the ARDS group and with a broader limit of agreement (-2.49 to 1.13 L/min).Clinical Relevance— the inspired sinewave test can be used to measure cardiac output noninvasively in mechanically ventilated subjects with and without acute respiratory distress syndrome
Prevalence of depression and anxiety in people with inflammatory bowel disease and associated healthcare use: population-based cohort study
No full textBackground Inflammatory bowel disease (IBD) has a significant impact on quality of life for many people.
Objective To assess the prevalence of common mental health conditions in IBD and the combined impact of IBD and mental health conditions on healthcare use and time off work.
Methods A UK population-based primary care database (Royal College of General Practitioners Research and Surveillance Centre) was used to identify adults with IBD (n=19 011) (Crohn’s disease (CD) or ulcerative colitis (UC)), and matched controls (n=76 044). Prevalences of anxiety, depressive episodes and depressive disorder recorded in primary care were assessed between 2016 and 2018. Outcomes comprised of rates of primary care visits, emergency secondary care visits, certificates for time off work, antidepressant and anxiolytic prescriptions.
Findings Mental health conditions were more common in people with CD than controls: anxiety episodes (3.5% vs 3.0%; p=0.02), depressive episodes (5.7% vs 4.1%; p<0.001) and depressive disorder (17.5% vs 12.9%; p<0.001), and people with UC versus controls: depressive episodes (4.4% vs 3.6%; p<0.001) and depressive disorder (14.2% vs 12.4%; p<0.001). Healthcare utilisation rates were higher in people with IBD than controls (primary care visits incidence rate ratio 1.47 (95% CI 1.43 to 1.51); emergency secondary care visits 1.87 (1.79 to 1.95); fitness for work certificates 1.53 (1.44 to 1.62); antidepressant use 1.22 (1.13 to 1.32); anxiolytic use 1.20 (1.01 to 1.41)). In people with IBD, mental health conditions were associated with additional increases in healthcare use and time off work.
Conclusion Depression and anxiety are more common in people with IBD than matched controls. Healthcare utilisation and prescribing of psychotropic medications are also higher in people with IBD. Mental health conditions in people with IBD are associated with additional healthcare use and time off work.
Clinical implications Evidence-based mental health support programmes, including psychological treatments, are needed for people with IBD
Global antibiotic dosing strategies in hospitalised children: characterising variation and implications for harmonisation of international guidelines
No full textBackground
Paediatric global antibiotic guidelines are inconsistent, most likely due to the limited pharmacokinetic and efficacy data in this population. We investigated factors underlying variation in antibiotic dosing using data from five global point prevalence surveys.
Methods & findings
Data from 3,367 doses of the 16 most frequent intravenous antibiotics administered to children 1 month–12 years across 23 countries were analysed. For each antibiotic, we identified standard doses given as either weight-based doses (in mg/kg/day) or fixed daily doses (in mg/day), and investigated the pattern of dosing using each strategy. Factors underlying observed variation in weight-based doses were investigated using linear mixed effects models. Weight-based dosing (in mg/kg/day) clustered around a small number of peaks, and all antibiotics had 1–3 standard weight-based doses used in 5%-48% of doses. Dosing strategy was more often weight-based than fixed daily dosing for all antibiotics apart from teicoplanin, which had approximately equal proportions of dosing attributable to each strategy. No strong consistent patterns emerged to explain the historical variation in actual weight-based doses used apart from higher dosing seen in central nervous system infections, and lower in skin and soft tissue infections compared to lower respiratory tract infections. Higher dosing was noted in the Americas compared to the European region.
Conclusions
Antibiotic dosing in children clusters around a small number of doses, although variation remains. There is a clear opportunity for the clinical, scientific and public health communities to consolidate behind a consistent set of global antibiotic dosing guidelines to harmonise current practice and prioritise future research
Ethical considerations in quality improvement: key questions and a practical guide
No full textQuality improvement (QI) provides a rigorous and innovative approach to improving patient's lives in the healthcare system. Still, it can pose challenges in understanding what ethical considerations apply to some projects to minimise the possibility of patient harm or prevent other ethical wrongs and potential staff burden. While many commentaries discuss the extent to which QI ethics should match research ethics, there is minimal literature regarding what QI project teams should do when considering ethics at the planning stage. This paper provides a practical walkthrough of some of the ethical considerations across the breadth of QI projects, starting from some of the key questions when planning a QI project and a guide for the different ethical considerations that may apply
