National Institute for Space Research
  • São José dos Campos, Brazil
Recent publications
Soil bulk density (ρb) is vital for assessing soil organic carbon (SOC) and nutrient stocks, as well as for modeling soil processes. Although ρb can be measured using traditional methods, these are labor-intensive and time-consuming. Consequently, there is a growing interest in developing pedotransfer functions (PTFs) to predict ρb based on more easily measured soil properties. The vast Brazilian territory, with different climates and biomes, presents a challenge for development of national-scale PTFs, particularly for ρb. In this study, a comprehensive dataset was compiled from various sources to develop ρb PTFs across Brazil. The dataset includes particle size distribution (PSD), SOC, ρb, sampling depth, soil order, land use, and geographic coordinates, allowing for the incorporation of additional numerical and categorical variables. Rigorous data preprocessing ensured quality and reliability. PTFs were developed using multiple linear regression (MLR) and Random Forest (RF) models. Model accuracy was evaluated using mean absolute error, bias, root mean square error (RMSE), and coefficient of determination. Both MLR and RF models accurately predicted ρb, with log-transformed PSD and SOC emerging as key predictors. The RF model slightly outperformed the MLR model (RMSE = 0.12 vs. 0.13 g cm−3) on the test dataset, underscoring the importance of environmental and categorical variables in predicting ρb. The developed PTFs, along with other PTFs for Brazil, were applied to estimate SOC stocks across different biomes and land uses. Best estimations were obtained with the RF model, with an R2 of 0.97, emphasizing the value of categorical variables in improving SOC stock estimations.
Studies on Convective Boundary Layer Height (CBLH) variability within the Amazon region are scarce. An alternative to obtaining CBLH values is to use reanalysis data, such as ERA5. This study used in situ temperature, humidity, and CO2 vertical profiles collected from 2010 to 2018 by small aircraft carried out within the scope of the CARBAM project (Long-Term Study of the Amazon Carbon Balance) in Amazonia. The flights were performed at 5 different locations in the Amazon (named SAN, ALF, RBA, TEF, and TAB), with significant variations in land use and land cover. Also, they represent different regional atmospheric processes associated. From the profiles, it was possible to estimate the CBLH values and compare/validate them with data provided by the ERA5. The results showed that ERA5 underestimates CBLH values by 5–12% for four sites (SAN, RBA, TEF, and TAB). At the fifth site (ALF), there was an overestimate of 18%, which can be attributed to the high levels of deforestation in that region. Despite the small differences in CBLH values estimated from ERA5 and experimental profiles, the correlations between them indicated a reasonable performance of ERA5 across several locations and periods investigated within the Amazon biome. These results highlight the reliability of ERA5 for obtaining spatial and temporal CBLH values in the Amazon.
Optical characterization of dissolved organic carbon (DOC) freshly collected from the circumneutral “white water” of the Rio Solimoes revealed that it had lower aromaticity, lower molecular weight, and a greater autochthonous content than DOC from the acidic “black water” of the Rio Negro. The tambaqui (Colossoma macropomum), a characid member of the Serrasalmidae, is a model neotropical fish that migrates annually between the two rivers. We analysed ionoregulatory responses of the tambaqui over 24 h in ion‐poor water at pH 7.0 and pH 4.0 in the absence and presence of 10 mg L⁻¹ Rio Solimoes DOC (“SOL DOC”). Measured parameters included transepithelial potential (TEP) across the gills, net flux rates, and plasma concentrations of Na⁺, Cl⁻, ammonia, and urea, and branchial Na⁺, K⁺ −ATPase, H⁺, ATPase, and carbonic anhydrase activities. Results were compared to our earlier study using similar protocols to examine the ionoregulatory effects of 10 mg L⁻¹ DOC (“SGC DOC”) collected from black water at São Gabriel da Cachoeira (SGC) in the upper Rio Negro. At pH 7.0, SOL DOC had no effect on the negative TEP across the gills. Exposure to pH 4.0 caused a marked depolarization of the TEP to positive values that was not ameliorated by the presence of SOL DOC. This contrasts with SGC DOC that drove TEP more negative at pH 7.0 and fully protected against the depolarization at pH 4.0. However, SOL DOC promoted positive balance of Na⁺ and Cl⁻ at pH 7.0 and helped ameliorate the negative balance of these ions seen at pH 4.0. This again contrasts with SGC DOC that exacerbated ion losses at pH 4.0. The protective effects of SOL DOC on ion balance maybe related to increased v‐type H⁺ ATPase activity in the gills, and unrelated to TEP. The very different responses to the two DOCs are discussed with respect to their optical properties, the time that they were in storage prior to testing (SOL <1 month, SGC 2 years), and the life history of the tambaqui in the two rivers.
The isolated/combined impacts of the positive Indian Ocean Dipole (pIOD) and El Niño (EN) events on precipitation in South America (SA) were investigated during austral winter and spring for the 1901–2012 period, considering both Atlantic Multidecadal Oscillation (AMO) phases. Under the warm phase (WAMO), EN events are well characterised in winter and, in spring, are accompanied by anomalous warming of the Tropical North Atlantic (TNA); thus, variations in the Walker circulation and the northward shifted Intertropical Convergence Zone (ITCZ) reduce precipitation over northern SA. In the cold AMO phase (CAMO), EN events are weak in winter. At the same time, an intense cooling in the equatorial North Atlantic, favoured by the CAMO, enhances moisture transport from the Amazon to central and southeastern Brazil, increasing precipitation in the South Atlantic Convergence Zone region. As EN develops in spring, the anticyclone off the east coast of SA associated with the Pacific‐South American (PSA) pattern decreases (increases) precipitation in central (southeastern) SA. The pIOD events predominantly occur during WAMO phase, when warming in the TNA is favoured by AMO. In winter, the moisture transport to northern SA is weakened, and the ITCZ remains northward shifted, inhibiting the precipitation over northeastern Brazil and southeastern Amazon. In spring, pIOD intensified ascending motions in equatorial Atlantic, increasing precipitation over northeastern Brazil. A wave train from the Indian Ocean strengthens the South Atlantic subtropical high, suppressing precipitation in central and eastern SA. EN‐pIOD events are well established in both AMO phases, though the sea surface temperature anomalies in the TNA depend on the AMO. During WAMO, reduced precipitation in western Amazon and northeastern SA is influenced by the Walker circulation, while in CAMO, TNA cooling enhances moisture transport from the Amazon into southeastern SA, where the PSA pattern and wave train from the Indian Ocean increase precipitation.
This paper addresses the use of cooperative systems in the management of innovative projects and their contribution to increasing the chances of success in the case study of the KC-390 Program, a significant project in the Brazilian aeronautical industry. Based on the administrative theory of cooperative systems, the study focuses on collaboration and trust in innovative projects, using the Technology Readiness Level as a guide for decisions. Complex products and systems require customized approaches due to their complexity and high engineering costs. Innovation in these projects depends on collaboration and trust between the developer and the requester. The methodology used includes applied and qualitative research, exploring bibliographic, documentary, and field research data. The KC-390 case study highlights the partnership between the Brazilian Air Force Command and Empresa Brasileira de Aeronaves (Embraer), evidencing how this relationship has been fundamental for technological development. The paper also explores the dual certification process of the KC-390, where the implementation of a collaborative process in the Conformity Demonstration Planning phase brought innovation to military certification. This innovation broke with the traditional paradigm of certification of aeronautical products in the country and was possible, mainly, due to the relationship of trust between the certifying authority and the integrating company. Keywords Cooperative system; Complex products and systems; Aerospace industry; Certification; KC-390 Program
The stress‐dominance hypothesis (SDH) predicts that trait variation at the community level increases with the availability of limiting resources, driving spatial and temporal patterns in above‐ground plant functional trait expression. Here, we test the assumption that the SDH also applies to fine roots responding to spatial and temporal fluctuations in soil resource availability. We monitored fine root mass and functional root traits associated with resource acquisition, that is specific root length (SRL), specific root tip abundance (SRTA) and branching index (BI), and traits related to stress tolerance, such as root diameter (RD) and tissue density (RTD) in a Central Amazonian tree community. To test for spatial differences in root traits, we separated the uppermost organic (O‐A horizon, 0–5 cm) and mineral soil (B horizon, 5–15 cm) layers, and for temporal fluctuations, we investigated the relationship of precipitation on community‐level root variation over a period of 27 months. In accordance with the SDH, we found that fine roots in the O‐A horizon have on average 15% higher SRL, 23% higher BI, 32% higher SRTA and 15% lower RTD than those in the B horizon. Similarly, precipitation shifted the community over time to higher mean SRL, BI and SRTA (r = 0.92, 0.84 and 0.94, p < 0.0001 respectively), although trait shifts occurred in the trimester after the rainy season onset, revealing a time‐lag between rainfall patterns and community response. We also detected a positive increase in trait range for SRL and SRTA with lagged precipitation (r = 0.90 and 0.79, p < 0.0001). On the other hand, traits related to stress showed a weaker negative relationship with instantaneous precipitation (r = −0.7 and −0.57, p = 0.046 and p = 0.1 for RD and RTD, respectively). Our results supported the SDH predictions that root systems will become more acquisitive in areas with more resources, and that the community will shift to more acquisitive but also broader trait dispersion as hydric stress decreases. We conclude that although higher resource availability may increase competition for acquisition, trait overdispersion seems to promote species coexistence. Our results highlight how dynamic root systems can be in response to environmental cues, cautioning the common practice of making conclusions about root traits adaptations to environmental gradients based on a single sampling observation. Read the free Plain Language Summary for this article on the Journal blog.
Heliotropic orbits are those in which the most distant point of the orbit, known as the apoapsis, remains, on average, oriented toward the Sun. When the apoapsis is directed opposite to the Sun, it is called an antiheliotropic orbit. This work examines the possibility of heliotropic orbits around the asteroid 34604 Vilhena (2000 TW60), considering perturbations caused by non-uniform distribution of mass, solar radiation pressure, and the gravitational influence of the Sun. Using the doubly averaged method, the disturbing potential applied to the Lagrange planetary equations is determined. With the doubly averaged method, quasi-heliotropic orbits are viable around the asteroid 2000 TW60. Furthermore, simulations of non-averaged dynamics were conducted, comparing the effects on the orbit both with and without shadow considerations. These findings have significant implications for understanding orbital dynamics around asteroid 2000 TW60 and may contribute to future space missions in the region.
Amazonian Dark Earths (ADEs) are fertile soils from the Amazon rainforest that harbor microorganisms with biotechnological potential. This study aimed to investigate the individual and potential synergistic effects of a 2% portion of ADEs and Urochloa brizantha cv. Marandu roots (Brazil’s most common grass species used for pastures) on soil prokaryotic communities and overall soil attributes in degraded soil. We conducted a comprehensive plant succession experiment in the greenhouse, utilizing vase soil samples for next-generation sequencing of 16 S rDNA, enzymatic activity assays, and soil chemical properties analysis. Univariate and multivariate analyses were performed to understand better the prokaryotic interactions within soil environments influenced by ADEs and U. brizantha roots, including differential abundance, diversity, and network analyses. Our findings reveal a complementary relationship between U. brizantha and ADEs, each contributing to distinct positive aspects of soil bacterial communities and quality. The combined influence of U. brizantha roots and ADEs exhibited synergies that enhanced prokaryotic diversity and enzyme activity. This balance supported plant growth and increased the general availability of beneficial bacteria in the soil, such as Chujaibacter and Curtobacterium while reducing the presence of potentially pathogenic taxa. This research provided valuable insights into the intricate dynamics of plant-soil feedback, emphasizing the potential for complementary interactions between specific plant species and unique soil environments like ADEs. The findings highlight the potential for pasture ecological rehabilitation and underscore the benefits of integrating plant and soil management strategies to optimize soil characteristics.
Understanding the South American Monsoon (SAM) rainy season is essential for water resources management and food security in West-Central Brazil (WCB). Therefore, this study aims to investigate the impact of different soil moisture conditions (dry, intermediate, and wet) on precipitation during the development (September-November), maturing (December-February), and weakening (March-May) stages of the rainy season in WCB, the central core of the SAM. To achieve this objective, a number of metrics were applied to the fifth generation of the European Centre for Medium-Range Weather Forecasts reanalysis (ERA5) data: the Temperature-Evapotranspiration Index, Terrestrial Coupling Index, Atmospheric Coupling Index, and Total Feedback Index. These metrics were employed in order to evaluate the local coupling and demand-limiting processes of evapotranspiration over WCB throughout periods of different soil moisture conditions and El Niño-Southern Oscillation (ENSO) phases. The results indicate that soil moisture is the primary limiting factor of the evapotranspiration regime during the SAM development stage over WCB while atmospheric processes are more influential in subsequent stages, with land-atmosphere coupling patterns being most pronounced in years with abnormally wet and dry soils as well as during the SAM development and maturity periods over WCB. Furthermore, the analyses conducted in this study have led to the conclusion that the ENSO phases do not influence the coupling patterns initially observed across different soil conditions during the periods of the SAM wet season over central Brazil.
South American sapote is a fruit native to the Brazilian Amazon. This fruit presents preservation challenges due to its high moisture content and the presence of bioactive compounds prone to degradation. This study aimed to evaluate the influence of the carrier materials inulin (IN) and maltodextrin (MD) with different dextrose equivalent (DE) values (5, 10, and 20) on the physicochemical, thermal, and morphological characteristics of the powdered South American sapote extract obtained by spray drying. Three wall material formulations were used: MD with a DE 5 and IN, MD with a DE 10 and IN, and MD with a DE 20 and IN (T1, T2, and T3, respectively). To compare the physicochemical qualities, the South American sapote extract (SASE) was examined without the addition of carrier agents. The MD DE 20/IN (T3) treatment stood out by presenting higher DPPH free radical scavenging activity with values of 0.79 ± 0.013 µmol TE g⁻¹/gd.b. and higher levels of total content of phenolic compounds (TPC) (39.30 ± 0.007 mg GAE .100 g⁻¹/gd.b.) (T3). The glass transition temperature (Tg) of the microparticles varied between 154.17 and 158.70 °C. The treatment with MD DE 20/IN (T3) demonstrated the best performance due to the lower thermogravimetric degradation, higher retention of volatile compounds, and preservation of phenolic compounds and antioxidant properties. Regarding morphology, the particles had a spherical shape with a smooth and pore-free surface but exhibited agglomeration. Graphical Abstract
In Brazil, Visceral Leishmaniases is caused by Leishmania infantum, and domestic dogs are the main reservoirs in its urban transmission cycle. As an alternative to euthanizing dogs, miltefosine has been used to treat canine visceral leishmaniasis since 2016. In this study, we have assessed the efficacy of miltefosine for treating canine visceral leishmaniasis in a new endemic area through follow-up of naturally infected dogs was evaluated. The clinical, parasitological, and histopathological characteristics of 21 dogs naturally infected with L. infantum were assessed at three time points: on the day before initiating miltefosine treatment (T0), immediately after treatment completion (T1), and 6 months after treatment completion (T2). Three dogs were treated exclusively with miltefosine, while eighteen received combination therapy with miltefosine with other treatments such as allopurinol, domperidone and immunotherapy. Skin biopsies were obtained from the abdomen to assess inflammatory responses and to quantify parasite loads using qPCR. The parasites were isolated using aspirates acquired from popliteal lymph nodes. Molecular and parasitological analyses confirmed the presence of L. infantum in all dogs, validating the effectiveness of skin and lymph node samples for diagnosis. The clinical conditions of the infected animals were improved and the skin parasite load decreased after treatment, even when distinct combination therapies were performed. The histopathological assessment revealed a miltefosine-induced reduction in the inflammatory response and a decrease in amastigotes number. Furthermore, a positive correlation was established between the reduction in parasite load and the enhancement of clinical scoring, as well as a reduction in the skin inflammatory response. Our findings suggest that miltefosine-based combination therapies reduce skin parasite load and improve clinical outcomes, while the dogs treated with miltefosine alone showed increased parasitic load and worsened clinical staging at T2. Considering this data belonging to a recent transmission area, treatment strategy suggests effective in controlling canine visceral leishmaniasis.
Northeast Brazil (NEB) is one of the driest regions in the country, with some areas, such as the sertão, receiving less than 400 mm/year. Despite this aridity, NEB is influenced by various synoptic-scale systems that contribute to intense rainfall events throughout the year. This study aimed to identify and analyze the synoptic-scale atmospheric patterns associated with extreme precipitation events in NEB. There were selected four events that occurred in the region over the past eight years and significantly impacted metropolitan areas. Two cases occurred in eastern, one in southern, and one in northern sector of the study region. The results revealed that these extreme precipitation events were associated with different synoptic-scale systems. The easterly wave disturbance (EWD), upper tropospheric cyclonic vortex (UTCV), South Atlantic convergence zone (SACZ) and intertropical convergence zone (ITCZ). EWD and UTCV were primarily responsible for the two eastern cases. The SACZ influenced the case that occurred in the southern, whereas the Atlantic ITCZ played a role in in northern case. Our findings indicate that these events are driven primarily by intense upper-level divergence and substantial moisture transport from the Atlantic Ocean to the continent, leading to significant moisture convergence. This study provides crucial insights into the factors driving extreme precipitation events in NEB, which can aid in validating numerical weather prediction models.
In regions with water shortages, detailed planning on water resource use is essential. The use of climate models for short- and medium-range forecasts is an important strategy for obtaining early information on the water requirements of crops and the water regime of a particular basin. This study aimed to assess the performance of seasonal climate forecasts and their applicability in estimating irrigation needs. To that end, the Simulation Model for Irrigation Strategies and climate forecast data derived from the Eta model were used. To analyze simulations, five members (days 13, 14, 15, 16 and 17) of the seasonal forecasts of rainfall and reference evapotranspiration for every month between 2001 and 2012 were used. The spread for reference evapotranspiration demonstrated that the model was unable to reproduce the behavior of this variable during the dry period. Comparison between forecasts months in advance showed no significant differences between the rainfall and the reference evapotranspiration forecasts. However, the results obtained for a one-month lead-time forecast exhibited superior performance. Key words: water resources; irrigation planning; Eta regional climate model; seasonal forecast errors
Multiple local anthropogenic pressures and climate changes threaten the biodiversity of aquatic insects in the Amazon. In this chapter, we review the impacts of various land use practices (e.g., urbanization, pasture, agriculture, mining, and dams) and climate change on aquatic insect assemblages in the Amazon region. We explore how these factors might influence the composition, richness, abundance, diversity, and ecosystem processes (e.g., leaf decomposition) of these insect communities. Finally, we outline future perspectives for studies of insects and aquatic environments in the Amazon.
Temperature stands out as one of the primary factors influencing physiological processes in ectothermic organisms. The impact of temperature increase on fish with diverse life histories varies significantly. Gaining knowledge about how fish respond to temperature elevation is crucial for understanding their susceptibility to climate change. Assessing aerobic metabolism provides valuable insights in this regard, and this chapter aims to evaluate the reliability of the electron transport system (ETS) activity assay by comparing physiological responses in fish from distinct climatic zones, specifically tropical and temperate regions. By conducting such comparisons, we can enhance our understanding of how fish from different climatic backgrounds may react to temperature increases and the potential implications for their adaptation to climate change.
The Northern Antarctic Peninsula (NAP) and the West Antarctic Ice Sheet (WAIS) are likely to respond rapidly to climate changes by increasing the collapse of peripheral ice shelves and the number of days above 0 °C. These facts make this region a representative hotspot of the global sea level rise and the location of one of the global climate tipping points (thresholds in the Earth system whose changes may become irreversible, if exceeded). Understanding the climate evolution of the NAP, based on past evidences, may help infer its future scenario. Herein, from a comprehensive survey of lacustrine sedimentation in proglacial and periglacial lakes/ponds, we investigated the impact of climate changes on the terrestrial environment in two complementary time scales (Late Holocene and contemporary age). For the longer time scale, regional climate database and biogeochemical properties of Lake Long/NAP sediment core, suggest warming between 4.0 and 2.0 kyr BP following a cooling phase towards the present, that endorse previously suggested Late Holocene Neoglacial (LHN). We attribute the LHN phase to a combined action of long-term decline in total solar irradiance, the Andean volcanism and the El Niño Southern Oscillation. For the contemporary age, we found a rapid coupled response of atmosphere/cryosphere/lithosphere to present warming levels.
This study assesses the performance of the latest phase of Coupled Model Intercomparison Project (CMIP6) models in simulating easterly wave disturbances (EWD) over the tropical South Atlantic (TSA) impacting northeast Brazil (NEB). Initially, we evaluate simulated precipitation from 17 historical CMIP, 16 AMIP, 7 hist-1950, and 10 highresSST-present models against the Global Precipitation Climatology Project (GPCP) dataset to identify models that accurately reproduce the spatial and temporal precipitation patterns in the study region. The ensemble's spatial analysis demonstrates their capability in reproducing annual and seasonal precipitation climatology. However, models underestimate precipitation intensity along NEB's coast while overestimating it in TSA and NEB's north. Model uncertainties tend to be greater with higher latitudes. The models represented the annual cycle in all subareas within the study region, particularly from July to October, albeit with a greater spread in the first half of the year, especially over the Intertropical Convergence Zone (ITCZ). Based on it, three top-performing models from each ensemble were selected for EWD evaluation. The automatic tracking algorithm for EWDs showed the model's ability to represent mean values of EWD lifetime (~ 6 days) and phase speed (~ 7 m s⁻¹) as found in ERA5 reanalysis. However, they failed to capture EWD's interannual variability or climatological mean frequency. Despite CMIP6 model weaknesses, they accurately identified two primary EWD genesis regions: one over the TSA and another near the West African coast. Overall, CMIP6 models, particularly atmospheric and high-resolution models (HighResMIP), effectively captured precipitation climatology and EWD characteristics over NEB and the adjacent TSA.
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1,508 members
Minella Martins
  • Center for Earth Systems Science
Maria Cristina Forti
  • Center for Earth Systems Science
Alber Ipia
  • Remote Sensing Division
Diogenes Salas Alves
  • C.G. Observ. Terra - OBT/DPI; PG-SER; PG-CST
Aline de Matos Valerio
  • Remote Sensing Division
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São José dos Campos, Brazil