Multiagent Reinforcement Learning (RL) solves complex tasks that require coordination with other agents through autonomous exploration of the environment. However, learning a complex task from ...scratch is impractical due to the huge sample complexity of RL algorithms. For this reason, reusing knowledge that can come from previous experience or other agents is indispensable to scale up multiagent RL algorithms. This survey provides a unifying view of the literature on knowledge reuse in multiagent RL. We define a taxonomy of solutions for the general knowledge reuse problem, providing a comprehensive discussion of recent progress on knowledge reuse in Multiagent Systems (MAS) and of techniques for knowledge reuse across agents (that may be actuating in a shared environment or not). We aim at encouraging the community to work towards reusing all the knowledge sources available in a MAS. For that, we provide an in-depth discussion of current lines of research and open questions.
Acute respiratory distress syndrome (ARDS) followed by repair with lung remodeling is observed in COVID-19. These findings can lead to pulmonary terminal fibrosis, a form of irreversible sequelae. ...There is evidence that TGF-β is intimately involved in the fibrogenic process. When activated, TGF-β promotes the differentiation of fibroblasts into myofibroblasts and regulates the remodeling of the extracellular matrix (ECM). In this sense, the present study evaluated the histopathological features and immunohistochemical biomarkers (ACE-2, AKT-1, Caveolin-1, CD44v6, IL-4, MMP-9, α-SMA, Sphingosine-1, and TGF-β1 tissue expression) involved in the TGF-β1 signaling pathways and pulmonary fibrosis. The study consisted of 24 paraffin lung samples from patients who died of COVID-19 (COVID-19 group), compared to 10 lung samples from patients who died of H1N1pdm09 (H1N1 group) and 11 lung samples from patients who died of different causes, with no lung injury (CONTROL group). In addition to the presence of alveolar septal fibrosis, diffuse alveolar damage (DAD) was found to be significantly increased in the COVID-19 group, associated with a higher density of Collagen I (mature) and III (immature). There was also a significant increase observed in the immunoexpression of tissue biomarkers ACE-2, AKT-1, CD44v6, IL-4, MMP-9, α-SMA, Sphingosine-1, and TGF-β1 in the COVID-19 group. A significantly lower expression of Caveolin-1 was also found in this group. The results suggest the participation of TGF-β pathways in the development process of pulmonary fibrosis. Thus, it would be plausible to consider therapy with TGF-β inhibitors in those patients recovered from COVID-19 to mitigate a possible development of pulmonary fibrosis and its consequences for post-COVID-19 life quality.
Set comparisons permeate a large number of data analysis workflows, in particular workflows in biological sciences. Venn diagrams are frequently employed for such analysis but current tools are ...limited.
We have developed InteractiVenn, a more flexible tool for interacting with Venn diagrams including up to six sets. It offers a clean interface for Venn diagram construction and enables analysis of set unions while preserving the shape of the diagram. Set unions are useful to reveal differences and similarities among sets and may be guided in our tool by a tree or by a list of set unions. The tool also allows obtaining subsets' elements, saving and loading sets for further analyses, and exporting the diagram in vector and image formats. InteractiVenn has been used to analyze two biological datasets, but it may serve set analysis in a broad range of domains.
InteractiVenn allows set unions in Venn diagrams to be explored thoroughly, by consequence extending the ability to analyze combinations of sets with additional observations, yielded by novel interactions between joined sets. InteractiVenn is freely available online at: www.interactivenn.net .
The demand for insect-pollinated crops is increasing. Conventional agricultural intensification heavily relies on increased input of fertilizers, which can have negative effects on local ...biodiversity. Such effects may be particularly accentuated in biodiversity hotspots that are naturally nutrient-poor. Ecological intensification of farming, i.e. practices that increase production through the increase of ecosystem services, emerges as an alternative to conventional intensification. For example, practices that boost abundance and diversity of crop pollinators can lead to substantial increases in cropland productivity. However, little is known about the synergisms and trade-offs between fertilizer input and such ecological intensification practices. Here we investigate interactive effects between fertilization practices and the provision of ecosystem services in a biodiversity hotspot where conventional agriculture is rapidly expanding (Brazilian savannas). We focus on a highly nitrogen-demanding crop species that benefits from pollinators (the common bean, Phaseolus vulgaris L.), for which nitrogen input greatly varies in the study region. Our findings show that positive effects of native pollinators on crop yield are most accentuated under low inputs of nitrogen (e.g. equal to or below 72kg ha-1). This interactive effect could be due to changes in flower visitor community composition or behaviour. Our study also suggests that landscape management practices that minimize isolation from patches of natural vegetation and maximize its cover nearby (within 500 meters) of production areas can increase pollinator and biocontrol agent abundance and richness. Overall, these results suggest that ecological intensification is a valuable alternative for common bean production in Brazil, and potentially other regions of the world. Land productivity can be enhanced if an adequate balance of chemical inputs and landscape management is achieved.
•Longitudinal vortex generator is effective to enhance the heat transfer in a solar water heater.•Vortex generator shape and angle of attack impact on the heat transfer more than Reynolds number.•The ...main and corner vortex is the main thermal-hydraulic phenomenology.•The asymmetrical plate is not effective to enhance the heat transfer.•The ratio between heat transfer and pressure drop penalty is higher for delta-winglet vortex generator.
The population growth and industrial development increase the demand for energy and the solar energy conversion is an important alternative to complement the world energy matrix. Flat plate solar collectors are devices that convert the solar energy into thermal energy and store the thermal energy in a working fluid, which could reduce the required electricity to heat water. However, an increase in the heat transfer in this type of equipment remains a great challenge. In the current research, two types of longitudinal vortex generators are placed into circular tube of a solar collector in order to enhance the heat transfer between tube walls and working fluid. The numerical modeling is performed by ANSYS 18.0 software and the flow pattern and heat transfer characteristics are analyzed in details for two types of vortex generators (delta-winglet and rectangular-winglet), Reynolds number of 300, 600 and 900, and angle of attack of 15°, 30° and 45°. Ten vortex generators were uniformly arranged on a flat-plate inside the tube. The results show that the delta-winglet and rectangular-winglet longitudinal vortex generators are in fact a passive technique capable to enhance the heat transfer in a solar water heater. The highest heat transfer is obtained for attack of the angle of 45° for both vortex generators, which is more pronounced for the rectangular-winglet vortex generator. However, the best ratio between the heat transfer and the pressure drop penalty is achieved for the delta-winglet vortex generator for angle of attack of 30°. The secondary flow is successfully generated by the inserts, although the corner vortex is observed only by rectangular-winglet vortex generator. Finally, the first vortex generator only impacts on the friction factor and can be removed with no significant losses on the heat transfer.
Display omitted
•A highly sensitive, specific and fast method for the analysis of 22 important phenolic compounds in fruit pulps.•Limit of detection (28.85–333.3pg/mL) and limit of quantification ...(96.15–1111pg/mL).•The method was applied to tropical fruits (açaí-do-Amazonas, acerola, cashew apple, camu-camu, pineapple and taperebá).•Contribution to chemical characterization of phenolic compounds from Brazilian exotic fruits.
Although Brazil is the third largest fruit producer in the world, several specimens consumed are not well studied from the chemical viewpoint, especially for quantitative analysis. For this reason and the crescent employment of mass spectrometry (MS) techniques in food science we selected twenty-two phenolic compounds with important biological activities and developed an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC–MS/MS) method using electrospray (ESI) in negative ion mode aiming their quantification in largely consumed Brazilian fruits (açaí-do-Amazonas, acerola, cashew apple, camu-camu, pineapple and taperebá). Multiple reaction monitoring (MRM) was applied and the selection of proper product ions for each transition assured high selectivity. Linearity (0.995<r2<0.999), limit of detection (28.85–333.3pg/mL), limit of quantification (96.15–1111pg/mL), inter- and intraday accuracy (>80%), precision (CV<20%) and extraction recovery rate (>80%) were satisfactory and showed that the method provides an efficient protocol to analyze phenolic compounds in fruit pulp extracts.
Mauritia flexuosa L. f. is a native palm tree from the South American Amazon rainforest commercialized in food, cosmetics and medicine. This paper reported the antioxidant, antimicrobial activities ...and characterization of phenolics from buriti leafs, trunk and fruit extracts. The total phenolics of the buriti extracts ranged from 378.07±3.12 to 86.89±3.15mg GAEq/100g and flavonoid content ranged from 567.16±1.15 to 246.84±1.11mg QUEREq/100g. The antioxidant activity assays with EC50 of 12.28±0.022 to 19.58±0.064mg/mL revealed the antioxidant capacity of M. flexuosa extracts. Results of the antimicrobial tests against some pathogenic bacteria revealed its strong ability to inhibit the growth of pathogen with low MIC values, where the best results were found with the leaf extract against the pathogen Pseudomonas aeruginosa (MIC 50μg/mL). The characterization of the phenolic compounds using Ultra Performance Liquid Chromatography coupled to Electrospray Ionization Tandem Mass Spectrometry (UPLC–ESI-MS/MS) was based on CID experiments of the observed precursors, thus 13 compounds were tentatively identified ((+)-catechin, caffeic acid hexoside, chlorogenic acid, quercetin, narigenin, myricetin, vitexin, scoparin, rutin, cyanidin-3-rutinoside, cyanidin-3-glucoside, (−)-epicatechin and kaempferol). These results indicate that antioxidant and antimicrobial activities in buriti phenolic extracts are quite potent and implicate the presence of compounds with potent free-radical-scavenging activity.
► The Amazonian fruit buriti (Mauritia flexuosa) is a source of phenolic compounds. ► Different parts of M. flexuosa showed different antioxidant capacities. ► Low antimicrobial activity was detected for the phenolic extracts. ► The main phenolic compounds were identified by UPLC–MS/MS.
Diclinanona calycina R. E. Fries popularly known as “envira”, is a species of the Annonaceae family endemic to Brazil. In our ongoing search for bioactive compounds from Annonaceae Amazon plants, the ...bark of D. calycina was investigated by classical chromatography techniques that yielded thirteen compounds (alkaloids and flavonoids) described for the first time in D. calycina as well as in the genus Diclinanona. The structure of these isolated compounds were established by extensive analysis using 1D/2D-NMR spectroscopy in combination with MS. The isolated alkaloids were identified as belonging to the subclasses: simple isoquinoline, thalifoline (1); aporphine, anonaine (2); oxoaporphine, liriodenine (3); benzyltetrahydroisoquinolines, (S)-(+)-reticuline (4); dehydro-oxonorreticuline (3,4-dihydro-7-hydroxy-6-methoxy-1-isoquinolinyl)(3-hydroxy-4-methoxyphenyl)-methanone) (5); (+)-1S,2R-reticuline Nβ-oxide (6); and (+)-1S,2S-reticuline Nα-oxide (7); tetrahydroprotoberberine, coreximine (8); and pavine, bisnorargemonine (9). While the flavonoids belong to the benzylated dihydroflavones, isochamanetin (10), dichamanetin (11), and a mixture of uvarinol (12) and isouvarinol (13). Compound 5 is described for the first time in the literature as a natural product. The cytotoxic activity of the main isolated compounds was evaluated against cancer and non-cancerous cell lines. Among the tested compounds, the most promising results were found for the benzylated dihydroflavones dichamanetin (10), and the mixture of uvarinol (12) and isouvarinol (13), which presented moderate cytotoxic activity against the tested cancer cell lines (<20.0 µg·mL−1) and low cytotoxicity against the non-cancerous cell line MRC-5 (>25.0 µg·mL−1). Dichamanetin (11) showed cytotoxic activity against HL-60 and HCT116 with IC50 values of 15.78 µg·mL−1 (33.70 µmol·L−1) and 18.99 µg·mL−1 (40.56 µmol·L−1), respectively while the mixture of uvarinol (12) and isouvarinol (13) demonstrated cytotoxic activity against HL-60, with an IC50 value of 9.74 µg·mL−1, and HCT116, with an IC50 value of 17.31 µg·mL−1. These cytotoxic activities can be attributed to the presence of one or more hydroxybenzyl groups present in these molecules as well as the position in which these groups are linked. The cytotoxic activities of reticuline, anonaine and liriodenine have been previously established, with liriodenine being the most potent compound.
Pharmaceuticals and illicit drugs are contaminants that are generally ubiquitous in wastewater treatment plant effluents with their release into the environment being well understood in North ...America, Europe, and Asia. There is, however, less information on the release of human pharmaceuticals and illicit drugs from regions undergoing rapid land use, economical, and social changes, such as Brazil. This encompasses many areas in the tropical zone where releases of emerging contaminants may impact pristine, bio‐diversity rich ecosystems. In this study, the occurrence of human pharmaceuticals and the illicit drug cocaine was determined in the Rio Negro and two of its tributaries that receive large amounts of untreated sewage, the Igarapé Mindu and the Igarapé do 40, passing through the city of Manaus, Brazil. In addition to cocaine and its metabolite, benzoylecognine, propranolol, diclofenac, amitriptyline, carbamazepine, carbamazepine‐epoxide, citalopram, metoprolol, carisoprolol, and sertraline were all detected in two urban tributaries at low ng/l concentrations similar to those typically found in urban surface waters. Concentrations in the Rio Negro were typically lower than detection limits due to the large level of dilution, although traces of a range of pharmaceuticals were detected in the Rio Negro in proximity of the confluence of the urban streams. The data represent new information on the emissions of pharmaceuticals from a newly industrialized region of Brazil.
Agricultural expansion is one of the main drivers of global pollinator loss. Paradoxically, this occurs while agriculture is becoming increasingly dependent on biotic pollination, raising concerns ...about food production. Integrated Crop Pollination (ICP), the use of both wild and managed pollinators in crop fields, can help conserve pollinator diversity while ensuring effective pollination services for growers. However, given the context‐dependent nature of this approach, there is an urgent need to evaluate its application across different landscapes and crops.
We apply the ICP approach to açaí palm (Euterpe oleracea Mart.) production in the eastern Brazilian Amazon to explore effects of a native stingless bee, Scaptotrigona aff. postica (Apidae: Meliponini), and landscape‐level forest conservation on yield and socioeconomic outcomes for açaí fruit growers. We assessed flower visitor assemblages and fruit production on 18 plantations across a landscape forest cover gradient, with bee colonies introduced on nine plantations. Field data were combined with information from semistructured interviews of growers to estimate yield and profit per hectare under different pollinator management scenarios.
Bee colonies and forest cover enhanced flower visitor abundance on palm inflorescences, but abundance increases attributed to managed bees were associated with shifts in flower visitor evenness and diversity (species richness), due to reduced visitation of wild bees near managed colonies.
Fruit production on inflorescences was positively related to bee abundance and bee diversity. Consequently, overall pollination performance was lower in plantations with bee colonies. This was repeated at the hectare scale, where yield and profit were associated with surrounding forest cover and not bee colonies.
Synthesis and applications. Managed bees can increase pollinator densities and fruit production, but the increased environmental and socioeconomic risks associated with this activity means açaí growers should prioritise forest conservation to safeguard pollination services and improve overall sustainability of açaí production in the eastern Brazilian Amazon.
Resumo
A expansão agrícola é um dos principais fatores que levam à perda de polinizadores em nível mundial. Paradoxalmente, isto vem ocorrendo no momento que a agricultura está se tornando cada vez mais dependente da polinização biótica, suscitando preocupações quanto à produção de alimentos. A Polinização Integrada de Cultivos (PIC), que consiste no uso de polinizadores silvestres e manejados nas áreas agrícolas, pode ajudar a conservar a diversidade dos polinizadores, e, ao mesmo tempo, assegurar serviços eficientes de polinização para os produtores. No entanto, considerando que tal abordagem dependente do contexto, há uma necessidade urgente de avaliá‐la em diferentes paisagens e culturas agrícolas.
Aplicamos a abordagem da PIC à produção de açaí (Euterpe oleracea Mart.) na Amazônia oriental brasileira, a fim de explorar os efeitos do manejo de uma abelha nativa sem ferrão, Scaptotrigona aff. postica (Apidae: Meliponini), e da conservação da floresta ao nível da paisagem, considerando a produção e benefícios socioeconômicos para os produtores de açaí. Avaliamos os grupos de visitantes florais e a produção de frutos em 18 plantações ao longo de um gradiente de cobertura florestal, aliado à introdução de colônias de abelhas em nove plantios. Os dados coletados no campo foram combinados com informações obtidas em entrevistas semiestruturadas com produtores, para estimar o rendimento e o lucro por hectare em diferentes cenários de manejo de polinizadores.
As colônias de abelhas e a cobertura florestal aumentaram a abundância de visitantes florais nas inflorescências das palmeiras, porém o incremento de abundância de abelhas manejadas foi associado às mudanças na uniformidade e diversidade dos visitantes florais (riqueza de espécies), devido à redução da visitação de abelhas silvestres próximo das colônias manejadas.
A produção de frutos nas inflorescências foi positivamente relacionada com a abundância e diversidade de abelhas. Consequentemente, o desempenho global da polinização foi inferior nas plantações com colônias de abelhas. Isto repetiu‐se à escala do hectare, onde o rendimento e o lucro estavam associados à cobertura florestal circundante e não às colônias de abelhas.
Síntese e aplicações. As abelhas manejadas podem aumentar a densidade de polinizadores e a produção de frutos, mas o aumento dos riscos ambientais e socioeconômicos associados a esta atividade demonstrou que os produtores de açaí devem dar prioridade à conservação da floresta para manter os serviços de polinização e melhorar a sustentabilidade global do cultivo de açaí na Amazônia oriental brasileira.
Managed bees can increase pollinator densities and fruit production, but the increased environmental and socioeconomic risks associated with this activity means açaí growers should prioritise forest conservation to safeguard pollination services and improve overall sustainability of açaí production in the eastern Brazilian Amazon.
PDF
