Dynamics of the Kuiper Belt

Our current knowledge of the dynamical structure of the Kuiper Belt is reviewed here. Numerical results on long term orbital evolution and dynamical mechanisms underlying the transport of objects out of the Kuiper Belt are discussed. Scenarios about the origin of the highly non-uniform orbital distribution of Kuiper Belt objects are described, as well as the constraints these provide on the formation and long term dynamical evolution of the outer Solar system. Possible mechanisms include an early history of orbital migration of the outer planets, a mass loss phase in the outer Solar system and scattering by large planetesimals. The origin and dynamics of the scattered component of the Kuiper Belt is discussed. Inferences about the primordial mass distribution in the trans-Neptune region are reviewed. Outstanding questions about Kuiper Belt dynamics are listed.Comment: 22 pages plus 8 figures added footnote, figure

Evolution of Lyman Alpha Galaxies: Stellar Populations at z ~ 0.3

We present the results of a stellar population analysis of 30 Lyman alpha emitting galaxies (LAEs) at z ~ 0.3, previously discovered with the Galaxy Evolution Explorer (GALEX). With a few exceptions, we can accurately fit model spectral energy distributions to these objects, representing the first time this has been done for a large sample of LAEs at z < 3, a gap of ~ 8 Gyr in the history of the Universe. From the 26/30 LAEs which we can fit, we find an age and stellar mass range of 200 Myr - 10 Gyr and 10^9 - 10^11 Msol, respectively. These objects thus appear to be significantly older and more massive than LAEs at high-redshift. We also find that these LAEs show a mild trend towards higher metallicity than those at high redshift, as well as a tighter range of dust attenuation and interstellar medium geometry. These results suggest that low-redshift LAEs have evolved significantly from those at high redshift.Comment: Accepted for publication in the Astrophysical Journal. Replaced with accepted version. Eight pages, four figures, in emulateapj forma

Increasing compliance with low tidal volume ventilation in the ICU with two nudge-based interventions: evaluation through intervention time-series analyses

Objectives: Low tidal volume (TVe) ventilation improves outcomes for ventilated patients, and the majority of clinicians state they implement it. Unfortunately, most patients never receive low TVes. ‘Nudges’ influence decision-making with subtle cognitive mechanisms and are effective in many contexts. There have been few studies examining their impact on clinical decision-making. We investigated the impact of 2 interventions designed using principles from behavioural science on the deployment of low TVe ventilation in the intensive care unit (ICU). Setting: University Hospitals Bristol, a tertiary, mixed medical and surgical ICU with 20 beds, admitting over 1300 patients per year. Participants: Data were collected from 2144 consecutive patients receiving controlled mechanical ventilation for more than 1 hour between October 2010 and September 2014. Patients on controlled mechanical ventilation for more than 20 hours were included in the final analysis. Interventions: (1) Default ventilator settings were adjusted to comply with low TVe targets from the initiation of ventilation unless actively changed by a clinician. (2) A large dashboard was deployed displaying TVes in the format mL/kg ideal body weight (IBW) with alerts when TVes were excessive. Primary outcome measure: TVe in mL/kg IBW. Findings: TVe was significantly lower in the defaults group. In the dashboard intervention, TVe fell more quickly and by a greater amount after a TVe of 8 mL/kg IBW was breached when compared with controls. This effect improved in each subsequent year for 3 years. Conclusions: This study has demonstrated that adjustment of default ventilator settings and a dashboard with alerts for excessive TVe can significantly influence clinical decision-making. This offers a promising strategy to improve compliance with low TVe ventilation, and suggests that using insights from behavioural science has potential to improve the translation of evidence into practice

Comparison of modified biophysical profile and Doppler ultrasound in prediction of perinatal outcome in high-risk pregnancies

Background: The objective of this present study was to compare MBPP and umbilical artery Doppler flow in high-risk pregnant women in prediction of perinatal outcome.Methods: A cohort study was done on 150 high-risk pregnant women over 16 months. Antenatal women with singleton pregnancy who delivered within 48 hours of performing MBPP and Doppler USG, with presence of ≥1 high-risk factor like pre-eclampsia/gestational HTN, BOH, post-dated pregnancy, FGR, GDM, maternal heart disease, anaemia, hypothyroidism and IHCP were included in the study. MBPP (NST and AFI) and umbilical artery Doppler was performed. Perinatal outcome was measured in terms of stillbirth/IUD, LBW, Apgar &lt;7 at 5 minutes, admission to NICU, neonatal death within 48 hours of delivery, MSL and neonatal seizures within 24-48 hours. Quantitative variables were compared using independent t-test/Mann Whitney test. Qualitative variables were correlated using Chi square test/Fisher exact test. Sensitivity, specificity, NPV, PPV were calculated and p-value &lt;0.05 was considered statistically significant. Data analysis was done using social sciences (SPSS) licensed version 21.0.Results: Majority belonged to the age group 21-25 years and were between 37-40 weeks of gestation. It was found that highest perinatal complications occurred in those with both abnormal MBPP and Doppler followed by those with only abnormal MBPP (p-value&lt;0.0001).Conclusions: MBPP is a better predictor of perinatal outcome compared to umbilical artery Doppler USG in high-risk pregnant women. MBPP should be done in all high-risk pregnancies even if Doppler is normal. Both the tests must be performed in all high-risk pregnancies to improve perinatal outcome

Kinetics of Degradation of Tetraphosphates

226-23

Dissociation Constants of Tetraphosphoric Acid

223-22