Free energy of formation of clusters of sulphuric acid and water molecules determined by guided disassembly

We evaluate the grand potential of a cluster of two molecular species, equivalent to its free energy of formation from a binary vapour phase, using a nonequilibrium molecular dynamics technique where guide particles, each tethered to a molecule by a harmonic force, move apart to disassemble a cluster into its components. The mechanical work performed in an ensemble of trajectories is analysed using the Jarzynski equality to obtain a free energy of disassembly, a contribution to the cluster grand potential. We study clusters of sulphuric acid and water at 300 K, using a classical interaction scheme, and contrast two modes of guided disassembly. In one, the cluster is broken apart through simple pulling by the guide particles, but we find the trajectories tend to be mechanically irreversible. In the second approach, the guide motion and strength of tethering are modified in a way that prises the cluster apart, a procedure that seems more reversible. We construct a surface representing the cluster grand potential, and identify a critical cluster for droplet nucleation under given vapour conditions. We compare the equilibrium populations of clusters with calculations reported by Henschel et al. [J. Phys. Chem. A 118, 2599 (2014)] based on optimised quantum chemical structures

ANALYSIS OF COVID-19 IN RURAL AMERICA

The outbreak of the novel coronavirus (SARS-CoV-2) in Wuhan, China and subsequent global pandemic illustrated the need of accurate forecasting and a greater understanding of the underlying dynamics of infectious diseases. In this dissertation, we examine the six most populous towns in the State of Montana through the lens of the classic SIR model. With this, we show that the six towns in question exhibit similar disease dynamics and population behavior within each wave. Furthermore, we conduct analysis on the age demographics of COVID-19 cases and deaths. This analysis corroborates the findings of the SIR model fits, in that the age demographics of cases, deaths, and case fatality rates are remarkably similar across all six towns, lending credence to the hypothesis that the dynamics of infectious diseases are fundamentally the same within rural towns in America

Model Agnostic Saliency for Weakly Supervised Lesion Detection from Breast DCE-MRI

There is a heated debate on how to interpret the decisions provided by deep learning models (DLM), where the main approaches rely on the visualization of salient regions to interpret the DLM classification process. However, these approaches generally fail to satisfy three conditions for the problem of lesion detection from medical images: 1) for images with lesions, all salient regions should represent lesions, 2) for images containing no lesions, no salient region should be produced,and 3) lesions are generally small with relatively smooth borders. We propose a new model-agnostic paradigm to interpret DLM classification decisions supported by a novel definition of saliency that incorporates the conditions above. Our model-agnostic 1-class saliency detector (MASD) is tested on weakly supervised breast lesion detection from DCE-MRI, achieving state-of-the-art detection accuracy when compared to current visualization methods

Pre and Post-hoc Diagnosis and Interpretation of Malignancy from Breast DCE-MRI

We propose a new method for breast cancer screening from DCE-MRI based on a post-hoc approach that is trained using weakly annotated data (i.e., labels are available only at the image level without any lesion delineation). Our proposed post-hoc method automatically diagnosis the whole volume and, for positive cases, it localizes the malignant lesions that led to such diagnosis. Conversely, traditional approaches follow a pre-hoc approach that initially localises suspicious areas that are subsequently classified to establish the breast malignancy -- this approach is trained using strongly annotated data (i.e., it needs a delineation and classification of all lesions in an image). Another goal of this paper is to establish the advantages and disadvantages of both approaches when applied to breast screening from DCE-MRI. Relying on experiments on a breast DCE-MRI dataset that contains scans of 117 patients, our results show that the post-hoc method is more accurate for diagnosing the whole volume per patient, achieving an AUC of 0.91, while the pre-hoc method achieves an AUC of 0.81. However, the performance for localising the malignant lesions remains challenging for the post-hoc method due to the weakly labelled dataset employed during training.Comment: Submitted to Medical Image Analysi

Bradycardia and atrial fibrillation in patients with stable coronary artery disease treated with ivabradine: an analysis from the SIGNIFY study

Aim: The aim of this study was to determine the impact of emergent bradycardia and atrial fibrillation (AF) on cardiovascular outcomes in 19 083 patients with stable coronary artery disease (CAD) receiving ivabradine or placebo (SIGNIFY, Study assessInG the morbidity–mortality beNefits of the If inhibitor ivabradine in patients with coronarY artery disease). Methods and results: Emergent bradycardia (resting heart rate <50 b.p.m. on 12-lead electrocardiogram) with ivabradine was reported in 3572 patients (37.4%) overall, and in 2242 (37.2%) patients with Canadian Cardiovascular Society (CCS) class ≥2 angina. There was no difference in outcomes over the course of the study in ivabradine-treated patients with and without emergent bradycardia in the whole population (2.5 vs. 2.9% per year, respectively, for primary composite endpoint of cardiovascular death or non-fatal myocardial infarction) or in the angina subgroup (2.5 vs. 3.2% per year). Neither was there an increase in the rate of primary endpoint after emergent bradycardia was recorded compared with those without emergent bradycardia. There were 754 cases of emergent AF on treatment (2.2% per year ivabradine vs. 1.5% per year placebo) and 469 in the patients with angina (2.2 vs. 1.5% per year). While outcomes occurred more frequently in patients in whom emergent AF had been recorded, there was no treatment–placebo difference in outcomes, including stroke, and no difference in treatment effect in patients with limiting angina. Conclusion: Both in the overall population as well as in the angina subset, bradycardia was common in ivabradine-treated patients, but did not appear to impact outcomes. Emergent AF was relatively rare and did not appear to have an impact on outcomes relative to placebo

Coupling the 1-D lake model FLake to the community land-surface model JULES

Results are presented from the merging of the lake model FLake into the community land-surface model JULES. It is shown, by comparison with observational data, that the combined JULES-FLake model performs more realistically than JULES with its original or upgraded parametrizations for inland water. Tests against observations from lakes in the UK and Sweden show that JULES-FLake gives results for both midlatitude and arctic lakes which are comparable to the original lake model, FLake. The accuracy of JULES-FLake as a general model of the land surface is therefore enhanced. Differences in sign of the model errors in the prediction of lake-ice thickness indicate possible future directions for development and testing of these models

Quality of life with ivabradine in patients with angina pectoris

Background—To explore the effect of ivabradine on angina-related quality of life (QoL) in patients participating in the Study Assessing the Morbidity–Mortality Benefits of the If Inhibitor Ivabradine in Patients with Coronary Artery Disease (SIGNIFY) QoL substudy. Methods and Results—QoL was evaluated in a prespecified subgroup of SIGNIFY patients with angina (Canadian Cardiovascular Society class score, ≥2 at baseline) using the Seattle Angina Questionnaire and a generic visual analogue scale on health status. Data were available for 4187 patients (2084 ivabradine and 2103 placebo). There were improvements in QoL in both treatment groups. The primary outcome of change in physical limitation score at 12 months was 4.56 points for ivabradine versus 3.40 points for placebo (E, 0.96; 95% confidence interval, –0.14 to 2.05; P=0.085). The ivabradine−placebo difference in physical limitation score was significant at 6 months (P=0.048). At 12 months, the visual analogue scale and the other Seattle Angina Questionnaire dimensions were higher among ivabradine-treated patients, notably angina frequency (P<0.001) and disease perception (P=0.006). Patients with the worst QoL at baseline (ie, those in the lowest tertile of score) had the best improvement in QoL for 12 months, with improvements in physical limitation and a significant reduction in angina frequency (P=0.034). The effect on QoL was maintained over the study duration, and ivabradine patients had better scores on angina frequency at every visit to 36 months. Conclusions—Treatment with ivabradine did not affect the primary outcome of change in physical limitation score at 12 months. It did produce consistent improvements in other self-reported QoL parameters related to angina pectoris, notably in terms of angina frequency and disease perception

Housing market dynamics and macroprudential policy

We perform an analysis to determine how well the introduction of a countercyclical loanto- value (LTV) ratio can reduce household indebtedness and housing price fluctuations compared with a monetary policy rule augmented with house price inflation. To this end, we construct a New Keynesian model in which a fraction of households borrow against the value of their houses and we introduce news shocks on housing demand. We estimate the model with Canadian data using Bayesian methods. We find that the introduction of news shocks can generate a housing market boom-bust cycle, the bust following unrealized expectations on housing demand. Our study also suggests that a countercyclical LTV ratio is a useful policy to reduce the spillover from the housing market to consumption, and to lean against news-driven boom-bust cycles in housing price and credit generated by expectations of future macroeconomic developments

Cal Poly Supermileage Vehicle Braking System

The Cal Poly Supermileage Vehicle (SMV) team has requested this team to design the braking systems for the 2021 Supermileage vehicle in accordance with the 2020 Shell Eco-marathon rules, weight restrictions, and team budget. A braking system consists of the front brake pedals, front pedal mount, cable management to the brake calipers, and the rear caliper mounts. This report outlines the concept design that our project group has developed for the redesign braking systems. Background research, objectives, and concept design developments, final design, manufacturing notes, and design verification testing data are documented for the project sponsors