The effectiveness of national-level containment and closure policies across income levels during the COVID-19 pandemic: an analysis of 113 countries

Despite heterogeneity in income levels, countries implemented similarly strict containment and closure policies to mitigate the COVID-19 pandemic. This research assesses the effectiveness of these containment and closure policies, which we defined as larger decreases in mobility and smaller COVID-19 case and death growth rates. Using daily data for 113 countries on mobility and cumulative COVID-19 case and death counts over the 130 days between February 15, 2020 and June 23, 2020, we examined changes in mobility, morbidity, and mortality growth rates across the World Bank’s income group classifications. Containment policies correlated with the largest declines in mobility in higher income countries. High-income countries also achieved lower COVID-19 case and death growth rates than low-income countries. This study finds better epidemiological outcomes of containment and closure policies for higher income countries than lower income countries. These findings urge policymakers to consider contextual differences, including levels of economic activity and the structure of the economy, when crafting policies in response to public health emergencies

An empirical evaluation of models of text document similarity

Modeling the semantic similarity between text documents presents a significant theoretical challenge for cognitive science, with ready-made applications in information handling and decision support systems dealing with text. While a number of candidate models exist, they have generally not been assessed in terms of their ability to emulate human judgments of similarity. To address this problem, we conducted an experiment that collected repeated similarity measures for each pair of documents in a small corpus of short news documents. An analysis of human performance showed inter-rater correlations of about 0.6. We then considered the ability of existing models—using wordbased, n-gram and Latent Semantic Analysis (LSA) approaches—to model these human judgments. The best performed LSA model produced correlations of about 0.6, consistent with human performance, while the best performed word-based and n-gram models achieved correlations closer to 0.5. Many of the remaining models showed almost no correlation with human performance. Based on our results, we provide some discussion of the key strengths and weaknesses of the models we examined

Ten steps or climbing a mountain: A study of Australian health professionals' perceptions of implementing the baby friendly health initiative to protect, promote and support breastfeeding

Background: The Baby Friendly Hospital (Health) Initiative (BFHI) is a global initiative aimed at protecting, promoting and supporting breastfeeding and is based on the ten steps to successful breastfeeding. Worldwide, over 20,000 health facilities have attained BFHI accreditation but only 77 Australian hospitals (approximately 23%) have received accreditation. Few studies have investigated the factors that facilitate or hinder implementation of BFHI but it is acknowledged this is a major undertaking requiring strategic planning and change management throughout an institution. This paper examines the perceptions of BFHI held by midwives and nurses working in one Area Health Service in NSW, Australia. Methods: The study used an interpretive, qualitative approach. A total of 132 health professionals, working across four maternity units, two neonatal intensive care units and related community services, participated in 10 focus groups. Data were analysed using thematic analysis. Results: Three main themes were identified: ‘Belief and Commitment’; ‘Interpreting BFHI’ and ‘Climbing a Mountain’. Participants considered the BFHI implementation a high priority; an essential set of practices that would have positive benefits for babies and mothers both locally and globally as well as for health professionals. It was considered achievable but would take commitment and hard work to overcome the numerous challenges including a number of organisational constraints. There were, however, differing interpretations of what was required to attain BFHI accreditation with the potential that misinterpretation could hinder implementation. A model described by Greenhalgh and colleagues on adoption of innovation is drawn on to interpret the findings. Conclusion: Despite strong support for BFHI, the principles of this global strategy are interpreted differently by health professionals and further education and accurate information is required. It may be that the current processes used to disseminate and implement BFHI need to be reviewed. The findings suggest that there is a contradiction between the broad philosophical stance and best practice approach of this global strategy and the tendency for health professionals to focus on the ten steps as a set of tasks or a checklist to be accomplished. The perceived procedural approach to implementation may be contributing to lower rates of breastfeeding continuation

Welshness in British Wales: Negotiating national identity at the margins

Popular interpretations of national identity often focus on the unifying qualities of nationhood. However, societies frequently draw hierarchical distinctions between the people and places who are ‘most national’, and those who are ‘least national’. Little attention is paid to these marginal places within the nation and the experiences of their inhabitants. This article helps to address this by analysing the ‘less Welsh’ British Wales region of Wales, a country that has traditionally possessed a hierarchical, regionally constituted nationhood. The article studies the British Wales region both ‘from above’ – considering how some areas develop as ‘less national’ – and ‘from below’, introducing empirical ethnographic work into ‘everyday Welshness’ in this area. Whilst previous work on hierarchical nationhood focuses on how hierarchies are institutionalized by the state, this article demonstrates how people at the margins of the nation actively negotiate their place in the nation. Whilst people in this area expressed a strong Welshness, they also struggled to place themselves in the nation because they had internalized their lowly place within the national hierarchy. The article demonstrates the importance of place and social class for national identity construction and draws attention to the role of power in the discursive construction of hierarchical nationhood

Turbulent flow as a cause for underestimating coronary flow reserve measured by Doppler guide wire

BACKGROUND: Doppler-tipped coronary guide-wires (FW) are well-established tools in interventional cardiology to quantitatively analyze coronary blood flow. Doppler wires are used to measure the coronary flow velocity reserve (CFVR). The CFVR remains reduced in some patients despite anatomically successful coronary angioplasty. It was the aim of our study to test the influence of changes in flow profile on the validity of intra-coronary Doppler flow velocity measurements in vitro. It is still unclear whether turbulent flow in coronary arteries is of importance for physiologic studies in vivo. METHODS: We perfused glass pipes of defined inner diameters (1.5 – 5.5 mm) with heparinized blood in a pulsatile flow model. Laminar and turbulent flow profiles were achieved by varying the flow velocity. The average peak velocity (APV) was recorded using 0.014 inch FW. Flow velocity measurements were also performed in 75 patients during coronary angiography. Coronary hyperemia was induced by intra-coronary injection of adenosine. The APV maximum was taken for further analysis. The mean luminal diameter of the coronary artery at the region of flow velocity measurement was calculated by quantitative angiography in two orthogonal planes. RESULTS: In vitro, the measured APV multiplied with the luminal area revealed a significant correlation to the given perfusion volumes in all diameters under laminar flow conditions (r(2 )> 0.85). Above a critical Reynolds number of 500 – indicating turbulent flow – the volume calculation derived by FW velocity measurement underestimated the actual rate of perfusion by up to 22.5 % (13 ± 4.6 %). In vivo, the hyperemic APV was measured irrespectively of the inherent deviation towards lower velocities. In 15 of 75 patients (20%) the maximum APV exceeded the velocity of the critical Reynolds number determined by the in vitro experiments. CONCLUSION: Doppler guide wires are a valid tool for exact measurement of coronary flow velocity below a critical Reynolds number of 500. Reaching a coronary flow velocity above the velocity of the critical Reynolds number may result in an underestimation of the CFVR caused by turbulent flow. This underestimation of the flow velocity may reach up to 22.5 % compared to the actual volumetric flow. Cardiologists should consider this phenomena in at least 20 % of patients when measuring CFVR for clinical decision making

A simple battle model with explanatory power

Attrition equations have military use and are also used in biological and economic modelling. We model the aggregation of attrition in a battle to explain the strong support in historical data for the log law, which conventionally is thought to apply mainly to losses through accident or illness. Support for the log law has been found in many studies of battle data and this has yet to be explained. Several historical studies found support for a mixture of attrition laws, suggesting that different laws could apply to different parts of the battle. We hypothesise that the log law could be supported through aggregation effects when other laws apply on a micro scale. We assume that all laws work at skirmish level and show that aggregation effects will only support the log law if the individual skirmishes being aggregated are themselves modelled by the log law. We argue that the extreme support for the log law in the Kursk dataset is due to an overwhelming support for that law at the level of individual skirmishes, and that the conventional use of square and linear law for skirmishes is incorrect. These results suggest that theoretical changes to attrition equations should be based on studies of small unit attrition as aggregation effects do not cause cross over from square or linear laws to log law.Adrian Hall Pincombe, Brandon Pincombe and Charles Pearc

Minimising fourth order correlations improves latent semantic analysis performance

Latent Semantic Analysis (LSA) uses semantic correlations across a corpora to reduce problems with polysemy, synonymy and inflexion when assessing document similarity. It uses singular value decomposition (SVD) to estimate a generalised linear model. This model assumes the appearance of terms in documents results from the additive noise and the product of topic and mixing matrices. Here, only the largest fourth order pairwise cross cumulants in the SVD output are minimised. Improved performance relative to LSA, as measured using precision-recall curves, is shown on the Medlars test set for a small number of retained vectors. This approach avoids the assumptions and complications of moving towards full higher order decorrelation and is also shown to produce better precision-recall curves than JADE and FastICA on this standard data set. The conclusion is that minimising fourth order correlations improves the performance of LSA on at least some information retrieval tasks. Three tasks likely to benefit from removing a small number of the largest pairwise cross cumulants are identification of writing genre, detection of copied computer code, and retrieval of objects or people from video streams