Regional climate models have been used since 1989 in order to improve climate simulation in regions where mesoscale forcings modulate the regional climate. These models are driven by time‐dependent ...lateral boundary conditions from global climate models or reanalysis, and this process is called dynamical downscaling. Here, we review the evolution of regional climate modeling, as well as present the studies developed for South America.
Regional climate models have been used since 1989 in order to improve climate simulation in regions where the mesoscale forcings modulate the regional climate. These models are driven by time‐dependent lateral boundary conditions from global climate models or reanalysis, and this process is called dynamical downscaling. Here, we review the evolution of regional climate modeling as well as present the studies developed for South America.
In this work, we analyze the growth of the cumulative number of confirmed infected cases by a novel coronavirus (COVID-19) until March 27, 2020, from countries of Asia, Europe, North America, and ...South America. Our results show that (i) power-law growth is observed in all countries; (ii) by using the distance correlation, the power-law curves between countries are statistically highly correlated, suggesting the universality of such curves around the world; and (iii) soft quarantine strategies are inefficient to flatten the growth curves. Furthermore, we present a model and strategies that allow the government to reach the flattening of the power-law curves. We found that besides the social distancing of individuals, of well known relevance, the strategy of identifying and isolating infected individuals in a large daily rate can help to flatten the power-laws. These are the essential strategies followed in the Republic of Korea. The high correlation between the power-law curves of different countries strongly indicates that the government containment measures can be applied with success around the whole world. These measures are scathing and to be applied as soon as possible.
The ultimate origin of water in the Earth's hydrosphere is in the deep Earth--the mantle. Theory and experiments have shown that although the water storage capacity of olivine-dominated shallow ...mantle is limited, the Earth's transition zone, at depths between 410 and 660 kilometres, could be a major repository for water, owing to the ability of the higher-pressure polymorphs of olivine--wadsleyite and ringwoodite--to host enough water to comprise up to around 2.5 per cent of their weight. A hydrous transition zone may have a key role in terrestrial magmatism and plate tectonics, yet despite experimental demonstration of the water-bearing capacity of these phases, geophysical probes such as electrical conductivity have provided conflicting results, and the issue of whether the transition zone contains abundant water remains highly controversial. Here we report X-ray diffraction, Raman and infrared spectroscopic data that provide, to our knowledge, the first evidence for the terrestrial occurrence of any higher-pressure polymorph of olivine: we find ringwoodite included in a diamond from Juína, Brazil. The water-rich nature of this inclusion, indicated by infrared absorption, along with the preservation of the ringwoodite, is direct evidence that, at least locally, the transition zone is hydrous, to about 1 weight per cent. The finding also indicates that some kimberlites must have their primary sources in this deep mantle region.
The genus Phaonantho Albuquerque (Anthomyiidae) comprises three species: P. mallochi (Curran), P. benevola Couri, and P. sordilloae Pamplona & Couri. These species are distributed in the neotropics. ...In this study, we updated the distributional knowledge for Phaonantho species, including the first record of the genus in Bolivia, Paraguay, Peru, and Mexico, and additional new records to Brazil.
The assessment of sources of moisture is key to the understanding of the hydrological cycle at different time scales, because it enables the establishment of source-sink relationships and the ...identification of the main moisture transport conveyors and associated processes, the result of which is precipitation. Gimeno et al. (2012) provided a comprehensive review of the state-of-the-art in the assessment of moisture source-sinks and how different approaches can contribute to improving our knowledge of this component of the Earth’s Climate System. Since then, a variety of studies have focused on more specific aspects of the moisture budget and the source-sink distribution across the globe by integrating observations, satellite-derived products, physical tracers and numerical modelling. Here, we summarise the main advances in the field related to the impact of the moisture source-sink relationship on rainfall distribution, and add to the scientific debate on the question of the residence time of water vapour. We also revisit some of the recent advances in the role of the major mechanisms of moisture transport at a global scale, mainly Atmospheric Rivers and Low-Level Jet systems (Gimeno et al., 2016), in terms of their effects on precipitation extremes. Finally, we set out some of the main challenges for future research.
This article explores the impact of electricity production broken down by energy source (fossils and renewables) on carbon dioxide emissions in South America over the 1980–2010 period. The ...contribution of the manuscript is in the analysis of the relationships between carbon dioxide emissions, the energy mix in electricity generation and its implications for economic growth in a region still insufficiently studied. Using ARDL approach, the empirical findings provide evidence of the cross-sectional dependence in the data and existence of cointegration. The pollution has a relationship with economic growth, and the fossil electricity in short-run. The estimations strongly reveal that renewable energy has a negative effect on CO2 emissions in long run. Also, in the long-run, fossil electricity has shown results become statistically insignificant. However, the adjustment mechanism corrected the model by around 27% in the following period. In this way, the electricity production at aggregate level is used a factor environmental pressure and as an indicator of economic activity in South America countries, where the renewable energy with an increasing long-run effect, remains an efficient substitute for the fossil-electricity. Thus, we recommend to the countries of South America that they maintain the long-term efforts to produce electricity from renewable sources.
•This study examines the interrelationship between CO2 emissions, electricity and GDP in South America.•We identified cross-section dependence and cointegration.•Contrary to GDP & fossil electricity, REs impact negatively on CO2 emissions.•The adjustment model with the variables applied stands at 27%.
Summary Background The role of positive end-expiratory pressure in mechanical ventilation during general anaesthesia for surgery remains uncertain. Levels of pressure higher than 0 cm H2 O might ...protect against postoperative pulmonary complications but could also cause intraoperative circulatory depression and lung injury from overdistension. We tested the hypothesis that a high level of positive end-expiratory pressure with recruitment manoeuvres protects against postoperative pulmonary complications in patients at risk of complications who are receiving mechanical ventilation with low tidal volumes during general anaesthesia for open abdominal surgery. Methods In this randomised controlled trial at 30 centres in Europe and North and South America, we recruited 900 patients at risk for postoperative pulmonary complications who were planned for open abdominal surgery under general anaesthesia and ventilation at tidal volumes of 8 mL/kg. We randomly allocated patients to either a high level of positive end-expiratory pressure (12 cm H2 O) with recruitment manoeuvres (higher PEEP group) or a low level of pressure (≤2 cm H2 O) without recruitment manoeuvres (lower PEEP group). We used a centralised computer-generated randomisation system. Patients and outcome assessors were masked to the intervention. Primary endpoint was a composite of postoperative pulmonary complications by postoperative day 5. Analysis was by intention-to-treat. The study is registered at Controlled-Trials.com , number ISRCTN70332574. Findings From February, 2011, to January, 2013, 447 patients were randomly allocated to the higher PEEP group and 453 to the lower PEEP group. Six patients were excluded from the analysis, four because they withdrew consent and two for violation of inclusion criteria. Median levels of positive end-expiratory pressure were 12 cm H2 O (IQR 12–12) in the higher PEEP group and 2 cm H2 O (0–2) in the lower PEEP group. Postoperative pulmonary complications were reported in 174 (40%) of 445 patients in the higher PEEP group versus 172 (39%) of 449 patients in the lower PEEP group (relative risk 1·01; 95% CI 0·86–1·20; p=0·86). Compared with patients in the lower PEEP group, those in the higher PEEP group developed intraoperative hypotension and needed more vasoactive drugs. Interpretation A strategy with a high level of positive end-expiratory pressure and recruitment manoeuvres during open abdominal surgery does not protect against postoperative pulmonary complications. An intraoperative protective ventilation strategy should include a low tidal volume and low positive end-expiratory pressure, without recruitment manoeuvres. Funding Academic Medical Center (Amsterdam, Netherlands), European Society of Anaesthesiology.
In the Mediterranean Andes region (MA; 30°–37°S), the main rivers are largely fed by melting snowpack and provide freshwater to around 10 million people on both sides of the Andes Mountains. Water ...resources in the MA are under pressure because of the extensive development of industrial agriculture and mining activities. This pressure is increasing as the region faces one of its worst recorded droughts. Previous studies have pointed to El Niño–Southern Oscillation (ENSO) as the main climatic force impacting the MA. However, the role of decadal and multidecadal climate variability, their spatial patterns, and the recurrence of long-term droughts remains poorly studied. In an attempt to better understand these factors, spatial and temporal patterns of hydroclimatic variability are analyzed using an extensive database of streamflow, precipitation, and snowpack covering the period between 1910 and 2011. These analyses are based on the combination of correlation, principal components, and kernel estimation techniques. Despite a general common pattern across the MA, the results presented here identify two hydroclimatic subregions, located north and south of 348S. While the interannual variability associated with ENSO is slightly stronger north of 348S, the variability associated with the Pacific decadal oscillation (PDO) and/or the interdecadal Pacific oscillation (IPO) index shows similar patterns in both regions. However, variations produced by the IPO forcing seem to be greater in the southern subregion since 1975. The estimations presented here on drought recurrence reveal a generalized increase in dry extremes since the 1950s. These findings suggest that the northern MA is more vulnerable to changes in hydrology and climate than the southern MA.
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