Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Controle de admissão de chamadas e reserva derecursos em redes móveis celulares

Handoff é o procedimento que transfere uma chamada em andamento de uma célula para outra à medida que uma estação móvel desloca-se através da área de cobertura de uma rede móvel celular. Se a célula alvo para a qual a estação móvel migra não tem recursos suficientes de banda passante, a chamada será descartada. Da perspectiva do usuário, o descarte de chamadas em andamento durante o handoff é menos desejável que o bloqueio de novas chamadas. Um mecanismo essencial para a provisão de QoS (Quality of Service) no nível de chamadas é o controle de admissão de chamadas (CAC) e reserva de recursos. O CAC deve assegurar não apenas as garantias dos requisitos de QoS das novas chamadas que chegam ao sistema, se aceitas, mas também garantir que os requisitos das chamadas existentes não serão deteriorados com a admissão de mais usuários. Esta tese propõe dois novos esquemas de controle de admissão de chamadas e reserva de recursos para redes móveis celulares. Nossas propostas evitam a sobrecarga de sinalização por usuário para a realização da reserva de recursos e, portanto, são escaláveis. Além disso, garantem os requisitos de QoS em termos de descarte de chamadas de handoff. A primeira proposta, Controle de Admissão Distribuído com Reserva de Recursos por Agregado (RV), utiliza previsão de mobilidade baseada em sistemas de posicionamento móvel e considera a banda passante requerida por chamadas de handoff em cada célula para a reserva de recursos durante uma janela de tempo. Introduzimos um novo conceito, denominado de reserva virtual, que objetiva prevenir a reserva por usuários. Nossa proposta é comparada, através de simulações, com o esquema fixo de canal de guarda e outras propostas otimizadas baseadas em reserva dinâmicas de recursos presentes na literatura. Os resultados de simulação mostraram a superioridade de nossa proposta na garantia de níveis máximos de probabilidade de descarte para handoffs, bem como um aumento no número de usuários admitidos, melhorando a utilização dos recursos da rede. Nossa segunda proposta, Controle de Admissão Local com Reserva de Recursos Baseada em Previsão de Series Temporais, considera a quantidade de banda passante a ser utilizada por chamadas de handoff baseando-se apenas em informação da utilização de banda passante coletada localmente em cada célula. Para este fim, propomos o uso de dois esquemas baseados em previsão de séries temporais para prever a carga de handoff para cada célula: Trigg and Leach (TL), uma técnica de alisamento exponencial adaptativo e modelos ARIMA (Autoregressive Integrated Moving Average). As previsões são realizadas localmente em cada célula. Estes esquemas são comparados e apesar da menor precisão do TL, os resultados de bloqueio de novas chamadas e descarte de handoffs são similares aos obtidos pelo esquema utilizando modelos ARIMA. Comparamos ainda as duas propostas apresentadas nesta tese e verificamos que o esquema local baseado em previsão de séries temporais mais simples utilizando o TL pode garantir limites máximos no descarte de chamadas de handoff similares aos da proposta distribuída com reserva de recursos por agregado

Optimising virtual networks over time by using Windows Multiplicative DEA model

Recently, the prediction of the most efficient configuration of a vast set of devices used for mounting an optimised cloud computing services and virtual networks environments have attracted growing attention. This paper proposes a paradigm shift in modelling transmission control protocol (TCP) behaviour over time in virtual networks by using data envelopment analysis (DEA) models. Firstly, it proves that self-similarity with long-range dependency is presented differently in every network device. This study implements a novel fractal dimension concept on virtual networks for prediction, where this key index informs if the transport layer forwards services with smooth or jagged behaviour over time. Another substantial contribution is proving that virtual network devices have a distinct fractal memory, TCP bandwidth performance, and fractal dimension over time, presenting themselves as important factor for forecasting of spatiotemporal data. Thus, a continuous stepwise fractal performance evaluation framework methodology is developed as an expert system for virtual network assessment and performs a fractal analysis as a knowledge representation. In addition, due to the limitations of classical DEA models, the windows multiplicative data envelopment analysis (WMDEA) model is used to dynamically assess the fractal time series from virtual network hypervisors. For knowledge acquisition, 50 different virtual network hypervisors were appraised as decision-making units (DMU). Finally, this expert system also acts as a math hypervisor capable of determining the correct fractal pattern to follow when delivering TCP services in an optimised virtual network