A machine learning approach to address air quality changes during the COVID-19 lockdown in Buenos Aires, Argentina

Having a prediction model for air quality at a low computational cost can be useful for research, forecasting, regulatory, and monitoring applications. This is of particular importance for Latin America, where rapid urbanization has imposed increasing stress on the air quality of almost all cities. In recent years, machine learning techniques have been increasingly accepted as a useful tool for air quality forecasting. Out of these, random forest has proven to be an approach that is both well-performing and computationally efficient while still providing key components reflecting the nonlinear relationships among emissions, chemical reactions, and meteorological effects. In this work, we employed the random forest methodology to build and test a forecasting model for the city of Buenos Aires. We used this model to study the deep decline in most pollutants during the lockdown imposed by the COVID-19 (COronaVIrus Disease 2019) pandemic by analyzing the effects of the change in emissions, while taking into account the changes in the meteorology, using two different approaches. First, we built random forest models trained with the data from before the beginning of the lockdown periods. We used the data to make predictions of the business-as-usual scenario during the lockdown periods and estimated the changes in concentrations by comparing the model results with the observations. This allowed us to assess the combined effects of the particular weather conditions and the reduction in emissions during the period when restrictions were in place. Second, we used random forest with meteorological normalization to compare the observational data from the lockdown periods with the data from the same dates in 2019, thus decoupling the effects of the meteorology from short-term emission changes. This allowed us to analyze the general effect that restrictions similar to those imposed during the pandemic could have on pollutant concentrations, and this information could be useful to design mitigation strategies. The results during testing showed that the model captured the observed hourly variations and the diurnal cycles of these pollutants with a normalized mean bias of less than 6 % and Pearson correlation coefficients of the diurnal variations between 0.64 and 0.91 for all the pollutants considered. Based on the random forest results, we estimated that the lockdown implied relative changes in concentration of up to −45 % for CO, −75 % for NO, −46 % for NO2, −12 % for SO2, and −33 % for PM10 during the strictest mobility restrictions. O3 had a positive relative change in concentration (up to an 80 %) that is consistent with the response in a volatile-organic-compound-limited chemical regime to the decline in NOx emissions. The relative changes estimated using the meteorological normalization technique show mostly smaller changes than those obtained by the random forest predictive model. The relative changes were up to −26 % for CO, up to −47 % for NO, −36 % for NO2, −20 % for PM10, and up to 27 % for O3. SO2 is the only species that had a larger relative change when the meteorology was normalized (up to 20 %). This points out the need for accounting not only for differences in emissions but also in meteorological variables in order to evaluate the lockdown effects on air quality. The findings of this study may be valuable for formulating emission control strategies that do not disregard their implication on secondary pollutants. We believe that the model itself can also be a valuable contribution to a forecasting system in the city and that the general methodology could also be easily applied to other Latin American cities as well. We also provide the first O3 and SO2 observational dataset in more that a decade for a residential area in Buenos Aires, and it is openly available at https://doi.org/10.17632/h9y4hb8sf8.1 (Diaz Resquin et al., 2021).Fil: Diaz Resquin, Melisa. Centro de Ciencia del Clima y la Resiliencia; Chile. Comisión Nacional de Energía Atómica; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Lichtig, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Alessandrello, Diego. Comisión Nacional de Energía Atómica; ArgentinaFil: De Oto, Marcelo. Comisión Nacional de Energía Atómica; ArgentinaFil: Gómez, Darío. Comisión Nacional de Energía Atómica; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Rossler, Cristina Elena. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Castesana, Paula Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentina. YPF - Tecnología; ArgentinaFil: Dawidowski, Laura Elena. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentin

A relação entre o comportamento do indicador de liquidez corrente das empresas de capital aberto do agronegócio pela variação de índices econômicos no Brasil

Inserted in a context of increased importance of agribusiness in the country's economy, concomitant with a period of negative economic variations, the objective of this article was to analyze the relationships between the fluctuation of variables related to the economic context of Brazil, with the behavior of the Liquidity Indicator Current (ILC) of 33 agribusiness companies, listed on the B3 SA Stock Exchange between 2010 and 2016. As a quantitative research, the static technique of Panel Data Analysis was used for the study of emerging data relationships. And the results showed that the most significant relationships for the ILC, came from the companies that support the sector. In the macroeconomic context, a direct relationship between the GDP and the ILC was identified, and at the microeconomic level, the unanimity of the relations between the ILC and the independent variables, indicated that the sector's economic activity was significantly related to the short-term financial surplus. publicly traded agribusiness companies. It was concluded that when measuring the ratio of the ILC by the behavior of the country's macroeconomic indices, that the variable presented a statistically significant relationship only with the GDP due to the operational increase that the increase in the country's wealth generated in the company's short-term assets. Regarding the statistical metric of the microeconomic relationship, the conclusion was that the ILC was driven by the positive balance of agribusiness trade balance in the period, and by the good performance of agriculture. Since livestock, observed within the Agribusiness GDP variable, was negatively related to the ILC of the analyzed companies, and therefore did not cooperate with the short term situation of the analyzed companies expressed from the Current Liquidity Indicator (ILC).Inserido num contexto de aumento da importância do agronegócio na economia do país, concomitante a um período de variações econômicas negativas, o objetivo deste artigo foi analisar as relações entre a flutuação de variáveis relacionadas ao contexto econômico do Brasil, com o comportamento do Indicador de Liquidez Corrente (ILC) de 33 empresas do agronegócio, listadas na Bolsa de Valores B3 S.A. entre 2010 e 2016. Como uma pesquisa quantitativa, utilizou-se para o estudo das relações emergentes dos dados, a técnica estática da Análise de Dados em Painel. E os resultados demonstraram que as relações mais significativas para o ILC, partiram das empresas de atividades de suporte ao setor. No contexto macroeconômico, identificou-se uma relação direta entre o PIB e o ILC, e em nível microeconômico a unanimidade das relações entre o ILC e as variáveis independentes, indicaram que a atividade econômica do setor se relacionou significativamente com a sobra financeira de curto prazo das empresas de capital aberto do agronegócio. Concluiu-se que ao medir a relação do ILC pelo comportamento dos índices macroeconômicas do País, que a variável apresentou relação estatisticamente significante apenas com o PIB pelo fato do incremento operacional que a elevação da riqueza do país gerou nos ativos de curto prazo da empresa. Já na métrica estatística da relação microeconômica, a conclusão foi de que o ILC foi impulsionado pelo saldo positivo da balança comercial do agronegócio no período, e pelo bom desempenho da agricultura. Já que a pecuária, observada dentro da variável do PIB do Agronegócio se relacionou negativamente com o ILC das empresas analisadas, e por isso não cooperou com a situação de curto prazo das empresas analisadas expressas a partir do Indicador de Liquidez Corrente (ILC).Insertado en un contexto de creciente importancia de los agronegocios en la economía del país, concomitante con un período de variaciones económicas negativas, el objetivo de este artículo fue analizar las relaciones entre la fluctuación de variables relacionadas con el contexto económico de Brasil, con el comportamiento del Indicador de Liquidez Actual (ILC) de 33 empresas de agronegocios, que cotizaron en la Bolsa de Valores de B3 SA entre 2010 y 2016. Como una investigación cuantitativa, la técnica estática de Panel Data Analysis se utilizó para el estudio de relaciones de datos emergentes. Y los resultados mostraron que las relaciones más significativas para la ILC provienen de las empresas que apoyan al sector. En el contexto macroeconómico, se identificó una relación directa entre el PIB y la ILC, y a nivel microeconómico, la unanimidad de las relaciones entre la ILC y las variables independientes, indicó que la actividad económica del sector estaba significativamente relacionada con el superávit financiero a corto plazo. empresas de agronegocios que cotizan en bolsa. Se concluyó que al medir la razón de la ILC por el comportamiento de los índices macroeconómicos del país, la variable presentaba una relación estadísticamente significativa solo con el PIB debido al aumento operativo que el aumento de la riqueza del país generó en los activos a corto plazo de la compañía. Con respecto a la métrica estadística de la relación microeconómica, la conclusión fue que la ILC fue impulsada por el saldo positivo de la balanza comercial de agronegocios en el período y por el buen desempeño de la agricultura. Dado que el ganado, observado dentro de la variable PIB de Agronegocios, estaba negativamente relacionado con la ILC de las empresas analizadas y, por lo tanto, no cooperó con la situación a corto plazo de las empresas analizadas expresada en el Indicador de Liquidez Actual (ILC)

Respiratory System Mechanics during Low Versus High Positive End-Expiratory Pressure in Open Abdominal Surgery: A Substudy of PROVHILO Randomized Controlled Trial

BACKGROUND: In the 2014 PROtective Ventilation using HIgh versus LOw positive end-expiratory pressure (PROVHILO) trial, intraoperative low tidal volume ventilation with high positive end-expiratory pressure (PEEP = 12 cm H2O) and lung recruitment maneuvers did not decrease postoperative pulmonary complications when compared to low PEEP (0-2 cm H2O) approach without recruitment breaths. However, effects of intraoperative PEEP on lung compliance remain poorly understood. We hypothesized that higher PEEP leads to a dominance of intratidal overdistension, whereas lower PEEP results in intratidal recruitment/derecruitment (R/D). To test our hypothesis, we used the volume-dependent elastance index %E2, a respiratory parameter that allows for noninvasive and radiation-free assessment of dominant overdistension and intratidal R/D. We compared the incidence of intratidal R/D, linear expansion, and overdistension by means of %E2 in a subset of the PROVHILO cohort. METHODS: In 36 patients from 2 participating centers of the PROVHILO trial, we calculated respiratory system elastance (E), resistance (R), and %E2, a surrogate parameter for intratidal overdistension (%E2 > 30%) and R/D (%E2 < 0%). To test the main hypothesis, we compared the incidence of intratidal overdistension (primary end point) and R/D in higher and lower PEEP groups, as measured by %E2. RESULTS: E was increased in the lower compared to higher PEEP group (18.6 [16.22] vs 13.4 [11.0.17.0] cm H2O\ub7L-1; P <.01). %E2 was reduced in the lower PEEP group compared to higher PEEP (-15.4 [-28.0.6.5] vs 6.2 [-0.8.14.0] %; P <.05). Intratidal R/D was increased in the lower PEEP group (61% vs 22%; P =.037). The incidence of intratidal overdistension did not differ significantly between groups (6%). CONCLUSIONS: During mechanical ventilation with protective tidal volumes in patients undergoing open abdominal surgery, lung recruitment followed by PEEP of 12 cm H2O decreased the incidence of intratidal R/D and did not worsen overdistension, when compared to PEEP 642 cm H2O

Venous thromboembolism risk and prophylaxis in hospitalised medically ill patients The ENDORSE Global Survey

Limited data are available regarding the risk for venous thromboembolism (VIE) and VIE prophylaxis use in hospitalised medically ill patients. We analysed data from the global ENDORSE survey to evaluate VTE risk and prophylaxis use in this population according to diagnosis, baseline characteristics, and country. Data on patient characteristics, VIE risk, and prophylaxis use were abstracted from hospital charts. VTE risk and prophylaxis use were evaluated according to the 2004 American College of Chest Physicians (ACCP) guidelines. Multivariable analysis was performed to identify factors associated with use of ACCP-recommended prophylaxis. Data were evaluated for 37,356 hospitalised medical patients across 32 countries. VIE risk varied according to medical diagnosis, from 31.2% of patients with gastrointestinal/hepatobiliary diseases to 100% of patients with acute heart failure, active noninfectious respiratory disease, or pulmonary infection (global rate, 41.5%). Among those at risk for VTE, ACCP-recommended prophylaxis was used in 24.4% haemorrhagic stroke patients and 40-45% of cardiopulmonary disease patients (global rate, 39.5%). Large differences in prophylaxis use were observed among countries. Markers of disease severity, including central venous catheters, mechanical ventilation, and admission to intensive care units, were strongly associated with use of ACCP-recommended prophylaxis. In conclusion, VIE risk varies according to medical diagnosis. Less than 40% of at-risk hospitalised medical patients receive ACCP-recommended prophylaxis. Prophylaxis use appears to be associated with disease severity rather than medical diagnosis. These data support the necessity to improve implementation of available guidelines for evaluating VIE risk and providing prophylaxis to hospitalised medical patients

36-month clinical outcomes of patients with venous thromboembolism: GARFIELD-VTE

Background: Venous thromboembolism (VTE), encompassing both deep vein thrombosis (DVT) and pulmonary embolism (PE), is a leading cause of morbidity and mortality worldwide.Methods: GARFIELD-VTE is a prospective, non-interventional observational study of real-world treatment practices. We aimed to capture the 36-month clinical outcomes of 10,679 patients with objectively confirmed VTE enrolled between May 2014 and January 2017 from 415 sites in 28 countries.Findings: A total of 6582 (61.6 %) patients had DVT alone, 4097 (38.4 %) had PE +/- DVT. At baseline, 98.1 % of patients received anticoagulation (AC) with or without other modalities of therapy. The proportion of patients on AC therapy decreased over time: 87.6 % at 3 months, 73.0 % at 6 months, 54.2 % at 12 months and 42.0 % at 36 months. At 12-months follow-up, the incidences (95 % confidence interval [CI]) of all-cause mortality, recurrent VTE and major bleeding were 6.5 (7.0-8.1), 5.4 (4.9-5.9) and 2.7 (2.4-3.0) per 100 person-years, respectively. At 36-months, these decreased to 4.4 (4.2-4.7), 3.5 (3.2-2.7) and 1.4 (1.3-1.6) per 100 person-years, respectively. Over 36-months, the rate of all-cause mortality and major bleeds were highest in patients treated with parenteral therapy (PAR) versus oral anti-coagulants (OAC) and no OAC, and the rate of recurrent VTE was highest in patients on no OAC versus those on PAR and OAC. The most frequent cause of death after 36-month follow-up was cancer (n = 565, 48.6 %), followed by cardiac (n = 94, 8.1 %), and VTE (n = 38, 3.2 %). Most recurrent VTE events were DVT alone (n = 564, 63.3 %), with the remainder PE, (n = 236, 27.3 %), or PE in combination with DVT (n = 63, 7.3 %).Interpretation: GARFIELD-VTE provides a global perspective of anticoagulation patterns and highlights the accumulation of events within the first 12 months after diagnosis. These findings may help identify treatment gaps for subsequent interventions to improve patient outcomes in this patient population