The Physical Propagator of a Slowly Moving Charge

We consider an electron which is electromagnetically dressed in such a way that it is both gauge invariant and that it has the associated electric and magnetic fields expected of a moving charge. We study the propagator of this dressed electron and, for small velocities, show explicitly at one loop that at the natural (on-shell) renormalisation point, $p_0=m$, ${\bold p}= m{\bold v}$, one can renormalise the propagator multiplicatively. Furthermore the renormalisation constants are infra-red finite. This shows that the dressing we use corresponds to a slowly moving, physical asymptotic field.Comment: 10 pages, plain TeX, 1 Figure (uuencoded needs epsfig.sty

Effectiveness of a primary care based complex intervention to promote self-management in patients presenting psychiatric symptoms: study protocol of a cluster-randomized controlled trial

BACKGROUND: Anxiety, Depression and Somatoform (ADSom) disorders are highly prevalent in primary care. Managing these disorders is time-consuming and requires strong commitment on behalf of the General Practitioners (GPs). Furthermore, the management of these patients is restricted by the high patient turnover rates in primary care practices, especially in the German health care system. In order to address this problem, we implement a complex, low-threshold intervention by an Advanced Practice Nurse (APN) using a mixture of case management and counseling techniques to promote self-management in these patients. Here we present the protocol of the “Self-Management Support for Anxiety, Depression and Somatoform Disorders in Primary Care” (SMADS)-Study. METHODS/DESIGN: The study is designed as a cluster-randomized controlled trial, comparing an intervention and a control group of 10 primary care practices in each case. We will compare the effectiveness of the intervention applied by an APN with usual GP-care. A total of 340 participants will be enrolled in the study, 170 in either arm. We use the Patient Health Questionnaire-German version (PHQ-D) as a screening tool for psychiatric symptoms, including patients with a score above 5 on any of the three symptom scales. The primary outcome is self-efficacy, measured by the General Self-Efficacy Scale (GSE), here used as a proxy for self-management. As secondary outcomes we include the PHQ-D symptom load and questionnaires regarding coping with illness and health related quality of life. Outcome assessments will be applied 8 weeks and 12 months after the baseline assessment. DISCUSSION: The SMADS-study evaluates a complex, low threshold intervention for ambulatory patients presenting ADSom-symptoms, empowering them to better manage their condition, as well as improving their motivation to engage in self-help and health-seeking behaviour. The benefit of the intervention will be substantiated, when patients can enhance their expected self-efficacy, reduce their symptom load and engage in more self-help activities to deal with their everyday lives. After successfully evaluating this psychosocial intervention, a new health care model for the management of symptoms of anxiety, depression and somatoform disorders for ambulatory patients could emerge, supplementing the work of the GP. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT0172638

Multi-Stage Magma Evolution in Intra-Plate Volcanoes: Insights From Combined in situ Li and Mg–Fe Chemical and Isotopic Diffusion Profiles in Olivine

Understanding the timescales of magma evolution and ascent is essential for interpreting geophysical monitoring signals from active volcanoes. In this study, we explore the potential of diffusion-driven Li concentration and isotope zoning profiles recorded by magmatic olivine crystals to unravel time scales of magma evolution processes. Lithium is a fast-diffusing element and may provide the opportunity to investigate changes in magma composition during magma ascent, shortly before eruption. Lithium chemical and isotopic profiles were determined in olivines from two localities in the Massif Central volcanic region (France) that have previously been investigated for their Fe–Mg isotope systematics. The combined investigation of isotopic and chemical profiles makes it possible to distinguish between crystal growth and diffusion events. Extremely low δ7Li-values down to −30.7‰ (relative to the commonly used Li isotope standard IRMM-16) in the crystal core regions and elevated values at crystal rims (δ7Li ∼8 to 10‰), along with increasing concentrations from cores (∼3 to 1 μg/g) toward rims (12 to 6 μg/g) were found. The shape and orientation of both the chemical and isotopic profiles indicate that they were dominantly generated by Li diffusion into and within the olivine grains during magmatic differentiation. While Mg–Fe isotope and major element profiles have been modeled by a single diffusion event (Oeser et al., 2015), concentration and isotope profiles of Li indicate that a second diffusion event took place, that was not recorded by the Mg–Fe exchange diffusion couple. The first diffusion event was interpreted as reflecting the residence of the olivine crystals in a magma chamber. As diffusion coefficients for Fe–Mg exchange diffusion are very well determined, the time scales of this event are likely best quantified by Mg–Fe isotopic exchange diffusion modeling (Oeser et al., 2015). This event probably also generated the low δ7Li observed in olivine cores. Comparing the length of the Mg–Fe and Li profiles could thus be used to determine the less well-known diffusion coefficients of Li in the studied olivine crystals. The findings of this study indicate that Li diffusion at low Li concentration levels, as typically observed in natural olivine, may be not as fast as previously thought. The second diffusion event might represent a short-lived event, such as degassing, related to the ascent of the magma and/or magma cooling after emplacement of the lava. Such a process would only affect Li, which, in contrast to the refractory elements Fe and Mg, is volatile during degassing. The findings of this study show that, according to their different diffusion rates and physiochemical properties, the combined use of spatially resolved Li and Mg–Fe chemical and isotopic diffusion profiles, is a powerful tool to model even multi-stage evolution processes in magmatic systems. © Copyright © 2020 Steinmann, Oeser, Horn and Weyer

A computational method for the systematic screening of reaction barriers in enzymes:searching for Bacillus circulans xylanase mutants with greater activity towards a synthetic substrate

We present a semi-empirical (PM6-based) computational method for systematically estimating the effect of all possible single mutants, within a certain radius of the active site, on the barrier height of an enzymatic reaction. The intent of this method is not a quantitative prediction of the barrier heights, but rather to identify promising mutants for further computational or experimental study. The method is applied to identify promising single and double mutants of Bacillus circulans xylanase (BCX) with increased hydrolytic activity for the artificial substrate ortho-nitrophenyl β-xylobioside (ONPX2). The estimated reaction barrier for wild-type (WT) BCX is 18.5 kcal/mol, which is in good agreement with the experimental activation free energy value of 17.0 kcal/mol extracted from the observed kcat using transition state theory (Joshi et al., 2001). The PM6 reaction profiles for eight single point mutations are recomputed using FMO-MP2/PCM/6-31G(d) single points. PM6 predicts an increase in barrier height for all eight mutants while FMO predicts an increase for six of the eight mutants. Both methods predict that the largest change in barrier occurs for N35F, where PM6 and FMO predict a 9.0 and 15.8 kcal/mol increase, respectively. We thus conclude that PM6 is sufficiently accurate to identify promising mutants for further study. We prepared a set of all theoretically possible (342) single mutants in which every amino acid of the active site (except for the catalytically active residues E78 and E172) was mutated to every other amino acid. Based on results from the single mutants we construct a set of 111 double mutants consisting of all possible pairs of single mutants with the lowest barrier for a particular position and compute their reaction profile. None of the mutants have, to our knowledge, been prepared experimentally and therefore present experimentally testable predictions

A third-generation dispersion and third-generation hydrogen bonding corrected PM6 method:PM6-D3H+

We present new dispersion and hydrogen bond corrections to the PM6 method, PM6-D3H+, and its implementation in the GAMESS program. The method combines the DFT-D3 dispersion correction by Grimme et al. with a modified version of the H+ hydrogen bond correction by Korth. Overall, the interaction energy of PM6-D3H+ is very similar to PM6-DH2 and PM6-DH+, with RMSD and MAD values within 0.02 kcal/mol of one another. The main difference is that the geometry optimizations of 88 complexes result in 82, 6, 0, and 0 geometries with 0, 1, 2, and 3 or more imaginary frequencies using PM6-D3H+ implemented in GAMESS, while the corresponding numbers for PM6-DH+ implemented in MOPAC are 54, 17, 15, and 2. The PM6-D3H+ method as implemented in GAMESS offers an attractive alternative to PM6-DH+ in MOPAC in cases where the LBFGS optimizer must be used and a vibrational analysis is needed, e.g., when computing vibrational free energies. While the GAMESS implementation is up to 10 times slower for geometry optimizations of proteins in bulk solvent, compared to MOPAC, it is sufficiently fast to make geometry optimizations of small proteins practically feasible

Negligible risk of inducing resistance in Mycobacterium tuberculosis with single-dose rifampicin as post-exposure prophylaxis for leprosy

Post-exposure prophylaxis (PEP) for leprosy is administered as one single dose of rifampicin (SDR) to the contacts of newly diagnosed leprosy patients. SDR reduces the risk of developing leprosy among contacts by around 60 % in the first 2-3 years after receiving SDR. In countries where SDR is currently being implemented under routine programme conditions in defined areas, questions were raised by health authorities and professional bodies about the possible risk of inducing rifampicin resistance among the M. tuberculosis strains circulating in these areas. This issue has not been addressed in scientific literature to date. To produce an authoritative consensus statement about the risk that SDR would induce rifampicin-resistant tuberculosis, a meeting was convened with tuberculosis (TB) and leprosy experts. The experts carefully reviewed and discussed the available evidence regarding the mechanisms and risk factors for the development of (multi) drug-resistance in M. tuberculosis with a view to the special situation of the use of SDR as PEP for leprosy. They concluded that SDR given to contacts of leprosy patients, in the absence of symptoms of active TB, poses a negligible risk of generating resistance in M. tuberculosis in individuals and at the population level. Thus, the benefits of SDR prophylaxis in reducing the risk of developing leprosy in contacts of new leprosy patients far outweigh the risks of generating drug resistance in M. tuberculosis

Towards embodied carbon benchmarks for buildings in Europe:#4 Bridging the performance gap: A Performance framework

Embodied Carbon in the Building Sector A new study, 'Towards embodied carbon benchmarks for buildings in Europe', by Ramboll, in collaboration with leading researchers from Aalborg University Build and KU Leuven sets out a framework for benchmarking and limiting the embodied carbon of new buildings. The study identifies solutions to measure embodied carbon emissions, define carbon budgets and targets. Importantly it includes recommendations for a baseline of current embodied carbon levels in new buildings, as well as considerations of the available carbon budget for these emissions. This will form the basis of a performance system in the shape of benchmarks for the reduction of embodied carbon. Download the reports #1 Facing the data challenge (https://doi.org/10.5281/zenodo.6120522) #2 Setting the baseline. A bottom-up approach (https://doi.org/10.5281/zenodo.5895051) #3 Defining budget-based targets. A top-down approach (https://doi.org/10.5281/zenodo.6120882) #4 Bridging the embodied carbon performance gap (https://doi.org/10.5281/zenodo.6120874) Summary report - The important takeaways in short (https://doi.org/10.5281/zenodo.6397514) Learn more To learn more about the study and download the reports from the study, go to our Embodied Carbon in the Building Sector website (https://c.ramboll.com/lets-reduce-embodied-carbon

Towards embodied carbon benchmarks for buildings in Europe:#3 Defining budget-based targets: A top-down approach

Embodied Carbon in the Building Sector A new study, 'Towards embodied carbon benchmarks for buildings in Europe', by Ramboll, in collaboration with leading researchers from Aalborg University Build and KU Leuven sets out a framework for benchmarking and limiting the embodied carbon of new buildings. The study identifies solutions to measure embodied carbon emissions, define carbon budgets and targets. Importantly it includes recommendations for a baseline of current embodied carbon levels in new buildings, as well as considerations of the available carbon budget for these emissions. This will form the basis of a performance system in the shape of benchmarks for the reduction of embodied carbon. Download the reports #1 Facing the data challenge (https://doi.org/10.5281/zenodo.6120522) #2 Setting the baseline. A bottom-up approach (https://doi.org/10.5281/zenodo.5895051) #3 Defining budget-based targets. A top-down approach (https://doi.org/10.5281/zenodo.6120882) #4 Bridging the embodied carbon performance gap (https://doi.org/10.5281/zenodo.6120874) Summary report - The important takeaways in short (https://doi.org/10.5281/zenodo.6397514) Learn more To learn more about the study and download the reports from the study, go to our Embodied Carbon in the Building Sector website (https://c.ramboll.com/lets-reduce-embodied-carbon) Change notes Version 1.1 The originally published version contained an error in "Table 1: Comparison of whole-life embodied emissions (in kgCO2eq/m2) according to empirical baseline and budget-based targets". Values have been corrected in v1.1