Publications by authors named "Alderson D"

Birth and death Markov processes can model stochastic physical systems from percolation to disease spread and, in particular, wildfires. We introduce and analyze a birth-death-suppression Markov process as a model of controlled culling of an abstract, dynamic population. Using analytic techniques, we characterize the probabilities and timescales of outcomes like absorption at zero (extinguishment) and the probability of the cumulative population (burned area) reaching a given size.

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Varicella is a highly contagious disease caused by the varicella zoster virus (VZV). While the disease is usually mild, severe complications can occur requiring costly hospitalization. A thorough understanding of the healthcare resource use (HCRU) and costs of varicella is needed to inform health-economic models of preventive strategies.

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Dynamic processes on networks, be it information transfer in the Internet, contagious spreading in a social network, or neural signaling, take place along shortest or nearly shortest paths. Computing shortest paths is a straightforward task when the network of interest is fully known, and there are a plethora of computational algorithms for this purpose. Unfortunately, our maps of most large networks are substantially incomplete due to either the highly dynamic nature of networks, or high cost of network measurements, or both, rendering traditional path finding methods inefficient.

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The Mission Dependency Index (MDI) is a risk metric used by US military services and federal agencies for guiding operations, management, and funding decisions for facilities. Despite its broad adoption for guiding the expenditure of billions in federal funds, several studies on MDI suggest it may have flaws that limit its efficacy. We present a detailed technical analysis of MDI to show how its flaws impact infrastructure decisions.

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Throughout South Asia, cattle are regularly treated with non-steroidal anti-inflammatory drugs (NSAIDs) and their carcasses are left for scavengers to consume. Residues of the NSAID diclofenac in cattle carcasses caused widespread mortality and catastrophic population declines in three species of Gyps vulture during the 1990s and 2000s. Diclofenac is now banned, but other NSAIDs are used in its place.

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Background: The 'second victim phenomenon' is a term attributed to the traumatic effect a medical error can have on healthcare professionals. Patient safety incidents have been shown to occur in as many as one in seven patients in hospital. These incidents cause significant, potentially devastating, trauma to patients and their relatives, and can have deep and long-lasting effects on the health professionals involved.

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Article Synopsis
  • Peatlands are important wetland areas that help store carbon and support various plants and animals, but they are being damaged by human activities.
  • Scientists have made progress in restoring peatlands, but we still need to learn how tiny living things in the soil (microbes) help these ecosystems work and recover from problems.
  • To improve peatland restoration, we need to study microbial communities better, create tools to monitor their health, and work with different experts to develop effective restoration practices.
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Background: There is a lack of large-scale randomised data evaluating the impact of sex and age in patients undergoing chemotherapy followed by potentially curative surgery for oesophagogastric cancer.

Patients And Methods: Individual patient data from four prospective randomised controlled trials were pooled using a two-stage meta-analysis. For survival analysis, hazard ratios (HRs) were calculated for patients aged <70 and ≥ 70 years, as well as between males and females.

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Objective: This study examined productivity losses in European patients with newly diagnosed multiple myeloma (NDMM) undergoing autologous stem cell transplantation (ASCT), to better understand and model the impact of NDMM and lenalidomide maintenance therapy on productivity from a patient and societal perspective.

Methods: A cross-sectional online patient survey was conducted across the UK, Germany, France, Spain and Italy. A partitioned survival model was used to estimate productivity loss and the impact of maintenance therapy, using human capital (HC) and friction cost approaches.

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Importance: Perioperative chemotherapy and surgery are a standard of care for operable gastroesophageal adenocarcinoma. Anti-HER2 therapy improves survival in patients with advanced HER2-positive disease. The safety and feasibility of adding lapatinib to perioperative chemotherapy should be assessed.

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The concept of "resilience analytics" has recently been proposed as a means to leverage the promise of big data to improve the resilience of interdependent critical infrastructure systems and the communities supported by them. Given recent advances in machine learning and other data-driven analytic techniques, as well as the prevalence of high-profile natural and man-made disasters, the temptation to pursue resilience analytics without question is almost overwhelming. Indeed, we find big data analytics capable to support resilience to rare, situational surprises captured in analytic models.

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Research Question: Does hemoglobin A1C (HbA1C) predict pre-diabetes (pre-DM) in a population of women with infertility and/or recurrent pregnancy loss (RPL), when considering the 75 g, 2-hour oral glucose tolerance test (2h GTT) as the gold standard?

Design: Retrospective study of 242 patients with infertility or RPL presenting to a university-affiliated reproductive endocrinology and infertility clinic between January 2012 and December 2016 who underwent screening for disorders of glucose metabolism with a 2h GTT. The prevalence of pre-DM as defined by HbA1C 5.7% to 6.

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Esophagectomy is a mainstay in curative treatment for esophageal cancer; however, the reported techniques and outcomes can vary greatly. Thirty-day mortality of patients with an intact anastomosis is 2-3% as compared to 17-35% in patients who have an anastomotic leak. The subsequent management of leaks postesophagectomy has great global variability with little consensus on a gold standard of practice.

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Peatlands provide a range of ecosystem services but are sensitive to changes in climate and land-use, and many peatlands globally are degraded. We analyse a large-scale, unique and diverse dataset, collected over 15 years, as part of major landscape scale blanket peat restoration projects in the south Pennines, UK. Trajectories of ecosystem change after restoration were assessed by measuring key ecosystem responses including: vegetation cover and indicator species; water table, runoff, and water quality.

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Objective: To present a novel network-based framework for the study of collaboration in surgery and demonstrate how this can be used in practice to help build and nurture collaborations that foster innovation.

Background: Surgical innovation is a social process that originates from complex interactions among diverse participants. This has led to the emergence of numerous surgical collaboration networks.

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Introduction: Per and polyfluoroalkyl substances (PFAS), including perfluorononanoic acid (PFNA) and perfluorooctanoic acid (PFOA), were detected in the community water supply of Paulsboro New Jersey in 2009.

Methods: A cross-sectional study enrolled 192 claimants from a class-action lawsuit, not affiliated with this study, who had been awarded a blood test for 13 PFAS. Study participants provided their blood test results and completed a survey about demographics; 105 participants also completed a health survey.

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Background: Postpartum women are at risk for unintended pregnancy. Access to immediate long-acting reversible contraception (LARC) may help decrease this risk, but it is unclear how many providers in the United States routinely offer this to their patients and what obstacles they face. Our primary objective was to determine the proportion of United States obstetric providers that offer immediate postpartum LARC to their obstetric patients.

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Objective: To investigate whether there is a difference in obstetrical and perinatal outcomes in blastocyst frozen-thawed embryo transfers (FETs) compared with cleavage-stage FET.

Design: A retrospective cohort study.

Setting: Not applicable.

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We analyze the stability of the network's giant connected component under impact of adverse events, which we model through the link percolation. Specifically, we quantify the extent to which the largest connected component of a network consists of the same nodes, regardless of the specific set of deactivated links. Our results are intuitive in the case of single-layered systems: the presence of large degree nodes in a single-layered network ensures both its robustness and stability.

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