Substrate Induced Denitrification over or under Estimates Shifts in Soil N2/N2O Ratios

Funding: Funding was provided by the Biotechnology and Biological Sciences Research Council, BBSRC UK (http://www.bbsrc.ac.uk). Grant number BB/H013431/1. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

An investigation into the matrix of support for medical students on hospital placement: a case study

Historically, consultants oversaw students on placements as part of ‘firms’. More recently, however, new roles have emerged that have dedicated educational support functions. The overall aim of this thesis is to investigate the structure of support for University of Birmingham medical students on hospital placements using a social learning theory lens. This in-depth, single site study begins with an investigation of how a newly introduced role of Senior Academy Tutor (SAT) supports students on hospital placement, followed by an exploration of the wider support matrix available to students. The first phase used routinely collected evaluation data to gauge Year 5 student sentiment about the SAT role, and then explored key themes with student focus groups and interviews with SATs. The second phase used a questionnaire survey to investigate how different roles support Year 3 to 5 students during their hospital placements. Key findings were that students’ orientation to their learning and to the matrix of support roles changes as they progress through the MBChB programme. From being concerned with learning basic skills and passing exams, students become more interested in learning the role of a junior doctor and joining the hospital community of practice

Pressure and temperature induced red-shift of the sodium D-line during HMX deflagration.

Funder: Emmanuel College Avik Chakravarty Memorial Fund for PhysicsFunder: AWE Defence Ordnance Safety Group, Science and TechnologyThe sodium D-line is often present in optical spectra of combustion due to its high prevalence and emissivity. Collision theory predicts the spectral peak to have a red-shift dependent on pressure, P, and temperature, T. Here we show that the conditions reached during deflagration of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) permit the red-shift of the sodium D-line to be calibrated to 1.5 GPa. Deflagration at these pressures is achieved using a split Hopkinson pressure bar apparatus, with temperatures of circa 2900 K from the greybody continuum away from spectral features. Lower deflagration pressures, of 0.5 to 0.9 GPa, are achieved in a fallhammer test, with temperatures of circa 4000 K. The red-shift exhibits the predicted PT-0.7 dependence with a constant of proportionality of (950 ± 30) GPa-1 · K0.7 · nm. Using the serendipitous presence of sodium, this optical technique allows for fast measurements of both pressure and temperature from the same light source in one measurement.Emmanuel College Avik Chakravarty Memorial Fund for Physics Defence Ordnance Safety Group, Science and Technolog

QED effective action at finite temperature and density

The QED effective action at finite temperature and density is calculated to all orders in an external homogeneous and time-independent magnetic field in the weak coupling limit. The free energy, obtained explicitly, exhibit the expected de\ Haas -- van\ Alphen oscillations. An effective coupling at finite temperature and density is derived in a closed form and is compared with renormalization group results.Comment: 10 pages, Latex, NORDITA-93/35 P, Goteborg ITP 92-2

Daily bathing with chlorhexidine-based soap and the prevention of Staphylococcus aureus transmission and infection

OBJECTIVE: Determine if daily bathing with chlorhexidine-based soap decreased methicillin-resistant Staphylococcus aureus (MRSA) transmission and ICU-acquired S. aureus infection among ICU patients. DESIGN: Prospective pre-post-intervention study with control unit SETTING: 1,250 bed tertiary-care teaching hospital PATIENTS: Medical and surgical intensive care unit (ICU) patients METHODS: Active surveillance for MRSA colonization was performed in both ICUs. In June 2005, a chlorhexidine bathing protocol was implemented in the surgical ICU. Changes in S. aureus transmission and infection rate before and after implementation were analyzed using time-series methodology. RESULTS: The intervention unit had a 20.68% decrease in MRSA acquisition after institution of the bathing protocol [pre-intervention 12.64 vs. post-intervention 10.03 cases/1000 patient-days-at-risk (95% CI: −5.19 – −0.04, p = 0.046)]. There was no significant change in MRSA acquisition in the control ICU during the study period [10.97 pre-June 2005 vs. 11.33/1000 patient-days at risk post-June 2005 (95% CI −37.40 – 15.19, p = 0.40)]. There was a 20.77% decrease in all S. aureus (including MRSA) acquisition in the intervention ICU from 2002-2007 [19.73 pre-intervention to 15.63 cases per 1000 patient-days at risk post-intervention (95% CI −7.25 – −0.95, p=0.012)]. The incidence of ICU-acquired MRSA infections decreased by 41.37% in the intervention ICU (1.96 pre-intervention vs. 1.15 infections per 1000 patient-days at risk post-intervention; p=0.001). CONCLUSIONS: Institution of daily chlorhexidine bathing in an ICU resulted in a decrease in the transmission of S. aureus, including MRSA. These data support the use of routine daily chlorhexidine baths to decrease rates of S. aureus transmission and infections

Predicting which species succeed in climate-forced polar seas

Understanding the mechanisms which determine the capacity of any species to adapt to changing environmental conditions is one of the foremost requirements in accurately predicting which populations, species and clades are likely to survive ongoing, rapid, climate change. The polar oceans are amongst the most rapidly changing environments on earth with reduced regional sea ice duration and extent, and their faunas expected sensitivity to warming and acidification. These changes potentially pose a significant threat to a number of polar fauna. There is, therefore, a critical need to assess the vulnerability of a wide range of species to determine the tipping points, or weak links in marine assemblages. Knowledge of the effect of multiple stressors on polar marine fauna has advanced over the last 40 years, but there are still many data gaps. This study applies ecological risk assessment techniques to the increasing knowledge of polar species’ physiological capacities to identify their exposure to climate change and their vulnerability to this exposure. This relatively rapid, semi-quantitative assessment, provides a layer of vulnerability on top of climate envelope models, until such times as more extensive physiological data sets can be produced. The risk assessment identified more species that are likely to benefit from the near future predicted change (the winners), especially predators and deposit feeders. Fewer species were scored at risk (the losers), although animals that feed on krill were consistently as under the most risk

Measuring the impact of wharf construction on the Antarctic Benthos

Shallow water Antarctic marine macroepifaunal assemblages live in one of the most naturally disturbed marine environments due to the impact of icebergs scouring the seafloor. They are, however, amongst the least anthropogenically impacted assemblages and are afforded protection under the Antarctic Treaty system. When the British Antarctic Survey’s Rothera Research Station wharf needed extending to accommodate the newly constructed UK polar research vessel, the RRS Sir David Attenborough, a Comprehensive Environmental Evaluation (CEE) was conducted to assess the impact. The macroepifauna likely to be impacted by the construction was surveyed through ROV videos of five transects, centered on the middle of the construction zone, from 10-100 m deep. A pre-construction survey was completed in March 2017, as part of the CEE impact assessment, and a post-build survey in 2022 (delayed from 2021, and reduced in scope, due to the COVID-19 pandemic). Sedimentation rates were also measured before and during construction and were high during the second summer when the wharf pilings were being back filled with crushed rock. The measured differences between pre- and post-construction assemblages were minor and were not reflected in the overall number of taxa (operational taxonomic units – OTU), or diversity, but there were subtle shifts in species composition. The largest differences in the macroepifauna were a reduction in the number of the common urchin, Sterechinus neumayeri, and seastar, Odontaster validus, and were within expected variability. The small changes detected in the macroepifauna indicate it was minimally impacted and/or recovered in the subsequent two years, therefore during wharf construction the accompanying mitigation measures were robust

Krebs von den Lungen 6 (KL-6) as a marker for disease severity and persistent radiological abnormalities following COVID-19 infection at 12 weeks

IntroductionAcute presentations of COVID-19 infection vary, ranging from asymptomatic carriage through to severe clinical manifestations including acute respiratory distress syndrome (ARDS). Longer term sequelae of COVID-19 infection includes lung fibrosis in a proportion of patients. Krebs von den Lungen 6 (KL-6) is a mucin like glycoprotein that has been proposed as a marker of pulmonary epithelial cell injury. We sought to determine whether KL-6 was a marker of 1) the severity of acute COVID-19 infection, or 2) the persistence of symptoms/radiological abnormalities at medium term follow up.MethodsProspective single centre observational study.ResultsConvalescent KL-6 levels were available for 93 patients (male 63%, mean age 55.8 years) who attended an 12-week follow up appointment after being admitted to hospital with COVID-19. For 67 patients a baseline KL-6 result was available for comparison. There was no significant correlations between baseline KL-6 and the admission CXR severity score or clinical severity NEWS score. Furthermore, there was no significant difference in the baseline KL-6 level and an initial requirement for oxygen on admission or the severity of acute infection as measured at 28 days. There was no significant difference in the 12-week KL-6 level and the presence or absence of subjective breathlessness but patients with abnormal CT scans at 12 weeks had significantly higher convalescent KL-6 levels compared to the remainder of the cohort (median 1101 IU/ml vs 409 IU/ml).ConclusionsThe association between high KL-6 levels at 12 weeks and persisting CT abnormalities (GGO/fibrosis), is a finding that requires further exploration. Whether KL-6 may help differentiate those patients with persisting dyspnoea due to complications rather than deconditioning or dysfunctional breathing alone, is an important future research question