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Abstract Land use change and atmospheric composition, two drivers of climate change, can interact to affect both local and remote climate regimes. Previous works have considered the effects of greenhouse gas buildup in the atmosphere and the effects of Amazon deforestation in atmospheric general circulation models. In this study, we investigate the impacts of the Brazilian Amazon savannization and global warming in a fully coupled ocean-land-sea ice-atmosphere model simulation. We find that both savannization and global warming individually lengthen the dry season and reduce annual rainfall over large tracts of South America. The combined effects of land use change and global warming resulted in a mean annual rainfall reduction of 44% and a dry season length increase of 69%, when averaged over the Amazon basin, relative to the control run. Modulation of inland moisture transport due to savannization shows the largest signal to explain the rainfall reduction and increase in dry season length over the Amazon and Central-West. The combined effects of savannization and global warming resulted in maximum daily temperature anomalies, reaching values of up to 14 °C above the current climatic conditions over the Amazon. Also, as a consequence of both climate drivers, both soil moisture and surface runoff decrease over most of the country, suggesting cascading negative future impacts on both agriculture production and hydroelectricity generation.

Abstract This study presents novel insight into the mechanisms of Atlantic Meridional Overturning Circulation (AMOC) reduction and its recovery under a warmer climate scenario. An one-thousand-year-long numerical simulation of a global coupled ocean–ice–atmosphere climate model, subjected to a stationary atmospheric radiative forcing, depict a coherent picture of the Arctic sea ice melting as a trigger for the initial AMOC reduction, along with decreases in the northward fluxes of salt and heat. Further atmospheric-driven ocean processes contribute to an erosion of the stable stratification of the fresher, yet colder waters in the surface layers of the North Atlantic, contributing to the recovery of a permanently altered AMOC.

In this study, we investigate the circulation and chemical processes associated with the deposition of the largest oil spill that reached the northeast coast of Brazil during the second half of 2019. Using the Oil Spill Contingency And Response model (OSCAR), we performed both deterministic and probabilistic simulations of oil spills from tanker ships that were present in the sea in the region at the time. The study used a dataset comprising the latitudinal distribution of oil sightings along the coast between 31 August and 2 December 2019 (box plot analysis) provided by the Brazilian Institute of Environment and Renewable Natural Resources (IBAMA). The total amount of oil that reached the coast during this period (approximately 5000 tons) and the date and location of the first sighting (30 August, in the southern part of the state of Paraíba (PB)) were also used as parameters to assess the results of the 31 simulations conducted for ships en route near the area of interest between July and August 2019. The results indicate that a leak having occurred through a mobile source is the most plausible hypothesis for explaining the observed temporal–spatial arrival of the oil leaks along the Brazilian coastline. We suggest that prevention, monitoring, and international cooperation are essential for reducing the risks of future environmental accidents of the kind analyzed in this study and to protect the environment and communities affected.

Complete savannization of the Amazon Basin would enhance the effects of climate change on local heat exposure and pose a risk to human health, according to climate model projections.

Destabilization of the water cycle threatens human lives and livelihoods. Meanwhile our understanding of whether and how changes in vegetation cover could trigger transitions in moisture availability remains incomplete. This challenge calls for better evidence as well as for the theoretical concepts to describe it. Here we briefly summarize the theoretical questions surrounding the role of vegetation cover in the dynamics of a moist atmosphere. We discuss the previously unrecognized sensitivity of local wind power to condensation rate as revealed by our analysis of the continuity equation for a gas mixture. Using the framework of condensation-induced atmospheric dynamics, we then show that with the temperature contrast between land and ocean increasing up to a critical threshold, ocean-to-land moisture transport reaches a tipping point where it can stop or even reverse. Land-ocean temperature contrasts are affected by both global and regional processes, in particular, by the surface fluxes of sensible and latent heat that are strongly influenced by vegetation. Our results clarify how a disturbance of natural vegetation cover, e.g., by deforestation, can disrupt large-scale atmospheric circulation and moisture transport: an increase of sensible heat flux upon deforestation raises land surface temperature and this can elevate the temperature difference between land and ocean beyond the threshold. In view of the increasing pressure on natural ecosystems, successful strategies of mitigating climate change require taking into account the impact of vegetation on moist atmospheric dynamics. Our analysis provides a theoretical framework to assess this impact. The available data for the Northern Hemisphere indicate that the observed climatological land-ocean temperature contrasts are close to the threshold. This can explain the increasing fluctuations in the continental water cycle including droughts and floods and signifies a yet greater potential importance for large-scale forest conservation.

A scientific cruise between November 15 and December 18, 2019 aboard R/V Vital de Oliveira collected offshore seawater samples at 59 stations between the states of Ceará and Bahia. The objective was to identify hydrocarbon levels potentially associated with the mysterious oil spill that reached the northeastern coast of Brazil. Median concentrations of aliphatic hydrocarbons (AHs, 0.79 µg L-1) and polycyclic aromatic hydrocarbons (PAHs, 5.39 ng L-1) do not indicate contamination by crude oil and are comparable to baseline levels previously found in other areas of the Brazilian continental margin. The detailed composition of both groups of hydrocarbons revealed that some samples were contaminated during sampling and/or handling on-board. The data set presented herein highlights the difficulty in tracking small oil patches spread over a huge ocean area and, more importantly, the need for improving protocols of national research vessels used to collect seawater samples for trace organic analyses.

Resumo Simulações climáticas para o clima presente (1960-2005) utilizando o Modelo Climático Regional Eta e o Modelo Hidrológico de Grandes Bacias (MGB), forçado com o Brazilian Earth System Model Ocean-Atmosphere (BESM-AO 2.5) foram realizadas. O objetivo deste trabalho é avaliar o desempenho do Modelo Regional Eta e o Modelo Hidrológico de Grandes Bacias (MGB) na representação dos componentes do balanço de água (precipitação, evapotranspiração, convergência de umidade, vazão, cota e área de inundação) sobre a bacia do rio Madeira. A característica de sumidouro de umidade (P > E) foi simulada pelo modelo regional. Entretanto, o modelo subestimou a precipitação (33%), a evapotranspiração (12%) e a convergência de umidade (6%). O MGB-IPH conseguiu representar o ciclo anual das vazões, níveis do rio (cota) e área de inundação. Também conseguiu reproduzir a translação e amplitude das ondas de cheia, e o atraso de 3 meses entre os máximos da área de inundação e a precipitação sobre a bacia do Madeira. O MGB-IPH mostrou-se uma ferramenta útil para estudos de variabilidade climática, mudanças no clima e no uso da terra, e também para sistemas operacionais de previsão hidrológica na bacia Amazônica.

The Brazilian Earth System Model (BESM-OA2.5), while simulating the historical period proposed by the fifth phase of the Coupled Model Intercomparison Project (CMIP5), detects an increasing trend in the sea surface height (SSH) on the southern hemisphere oceans relative to that of the pre-industrial era. The increasing trend is accentuated in the CMIP5 RCP4.5 and RCP8.5 future scenarios with higher concentrations of greenhouse gases in the atmosphere. This study sheds light on the sources of such trends in these regions. The results suggest an association with the thermal expansion of the oceans in the upper 700m due to a gradual warming inflicted by those future scenarios. BESM-OA2.5 presents a surface height increase of 0.11m in the historical period of 1850–2005. Concerning future projections, BESM-OA2.5 projects SSH increases of 0.14 and 0.23m (relative to the historical 2005 value) for RCP4.5 and RCP8.5, respectively, by the end of 2100. These increases are predominantly in a band of latitude within 35–60°S in the Atlantic and Indian oceans. The reproducibility of the trend signal detected in the BESM-OA2.5 simulations is confirmed by the results of three other CMIP5 models.

In this work, we report the ongoing implementation of online-coupled aerosol–cloud microphysical–radiation interactions in the Brazilian global atmospheric model (BAM) and evaluate the initial results, using remote-sensing data for JFM 2014 and JAS 2019. Rather than developing a new aerosol model, which incurs significant overheads in terms of fundamental research and workforce, a simplified aerosol module from a preexisting global aerosol–chemistry–climate model is adopted. The aerosol module is based on a modal representation and comprises a suite of aerosol microphysical processes. Mass and number mixing ratios, along with dry and wet radii, are predicted for black carbon, particulate organic matter, secondary organic aerosols, sulfate, dust, and sea salt aerosols. The module is extended further to include physically based parameterization for aerosol activation, vertical mixing, ice nucleation, and radiative optical properties computations. The simulated spatial patterns of surface mass and number concentrations are similar to those of other studies. The global means of simulated shortwave and longwave cloud radiative forcing are comparable with observations with normalized mean biases ≤11% and ≤30%, respectively. Large positive bias in BAM control simulation is enhanced with the inclusion of aerosols, resulting in strong overprediction of cloud optical properties. Simulated aerosol optical depths over biomass burning regions are moderately comparable. A case study simulating an intense biomass burning episode in the Amazon is able to reproduce the transport of smoke plumes towards the southeast, thus showing a potential for improved forecasts subject to using near-real-time remote-sensing fire products and a fire emission model. Here, we rely completely on remote-sensing data for the present evaluation and restrain from comparing our results with previous results until a complete representation of the aerosol lifecycle is implemented. A further step is to incorporate dry deposition, in-cloud and below-cloud scavenging, sedimentation, the sulfur cycle, and the treatment of fires.

Coastal ocean observing and modeling systems (coastal observatories), connected with regional and global ocean systems, improve the quality of information and forecasts for effective management of safe and sustainable maritime activities. The public availability of systematic and long-term information of the ocean is an engine for the Blue Economy, boosting economic growth, employment, and innovation. An overview of some Brazilian initiatives is presented in this paper, involving universities, private companies, federal and state agencies, covering institutions from south to north of Brazil. Although these initiatives focus mainly on ocean physics, integrated efforts can extend the scope to include biogeochemistry and marine biodiversity, helping to address interdisciplinary problems. Existing initiatives can be connected, and new ones fostered, to fill in the gaps of temporal and spatial coverage of ocean monitoring in the vast oceanic area under Brazilian jurisdiction (nationally referred to as the Blue Amazon, in reference to the similar richness of the Amazon Forest). The alignment among national and regional initiatives, as well as with international programs, can be promoted if coordinated by a national-level organization, maximizing the return of public investment and socioeconomic benefits. In light of international examples, possible future institutional arrangements are discussed, leveraging from existing national public policies and international cooperation that Brazil is taking part. The United Nations Decade of Ocean Science for Sustainable Development is a timely opportunity to encourage an institutional arrangement to support and articulate an integrated network of coastal observatories in Brazil.

One of the most visible signs of global warming is the fast change in the polar regions. The increase in Arctic temperatures, for instance, is almost twice as large as the global average in recent decades. This phenomenon is known as the Arctic Amplification and reflects several mutually supporting processes. An equivalent albeit less studied phenomenon occurs in Antarctica. Here, we used numerical climate simulations obtained from CMIP5 and CMIP6 to investigate the effects of +1.5, 2 and 3 °C warming thresholds for sea ice changes and polar amplification. Our results show robust patterns of near-surface air-temperature response to global warming at high latitudes. The year in which the average air temperatures brought from CMIP5 and CMIP6 models rises by 1.5 °C is 2024. An average rise of 2 °C (3 °C) global warming occurs in 2042 (2063). The equivalent warming at northern (southern) high latitudes under scenarios of 1.5 °C global warming is about 3 °C (1.8 °C). In scenarios of 3 °C global warming, the equivalent warming in the Arctic (Antarctica) is close to 7 °C (3.5 °C). Ice-free conditions are found in all warming thresholds for both the Arctic and Antarctica, especially from the year 2030 onwards.

The scope of this work was to evaluate simulated carbon monoxide (CO) and aerosol optical depth (AOD) from the CAM-chem model against observed satellite data and additionally explore the empirical relationship of CO, AOD and fire radiative power (FRP). The simulated seasonal global concentrations of CO and AOD were compared, respectively, with the Measurements of Pollution in the Troposphere (MOPITT) and the Moderate-Resolution Imaging Spectroradiometer (MODIS) satellite products for the period 2010–2014. The CAM-chem simulations were performed with two configurations: (A) tropospheric-only; and (B) tropospheric with stratospheric chemistry. Our results show that the spatial and seasonal distributions of CO and AOD were reasonably reproduced in both model configurations, except over central China, central Africa and equatorial regions of the Atlantic and Western Pacific, where CO was overestimated by 10–50 ppb. In configuration B, the positive CO bias was significantly reduced due to the inclusion of dry deposition, which was not present in the model configuration A. There was greater CO loss due to the chemical reactions, and shorter lifetime of the species with stratospheric chemistry. In summary, the model has difficulty in capturing the exact location of the maxima of the seasonal AOD distributions in both configurations. The AOD was overestimated by 0.1 to 0.25 over desert regions of Africa, the Middle East and Asia in both configurations, but the positive bias was even higher in the version with added stratospheric chemistry. By contrast, the AOD was underestimated over regions associated with anthropogenic activity, such as eastern China and northern India. Concerning the correlations between CO, AOD and FRP, high CO is found during March–April–May (MAM) in the Northern Hemisphere, mainly in China. In the Southern Hemisphere, high CO, AOD, and FRP values were found during August–September–October (ASO) due to fires, mostly in South America and South Africa. In South America, high AOD levels were observed over subtropical Brazil, Paraguay and Bolivia. Sparsely urbanized regions showed higher correlations between CO and FRP (0.7–0.9), particularly in tropical areas, such as the western Amazon region. There was a high correlation between CO and aerosols from biomass burning at the transition between the forest and savanna environments over eastern and central Africa. It was also possible to observe the transport of these pollutants from the African continent to the Brazilian coast. High correlations between CO and AOD were found over southeastern Asian countries, and correlations between FRP and AOD (0.5–0.8) were found over higher latitude regions such as Canada and Siberia as well as in tropical areas. Higher correlations between CO and FRP are observed in Savanna and Tropical forests (South America, Central America, Africa, Australia, and Southeast Asia) than FRP x AOD. In contrast, boreal forests in Russia, particularly in Siberia, show a higher FRP x AOD correlation than FRP x CO. In tropical forests, CO production is likely favored over aerosol, while in temperate forests, aerosol production is more than CO compared to tropical forests. On the east coast of the United States, the eastern border of the USA with Canada, eastern China, on the border between China, Russia, and Mongolia, and the border between North India and China, there is a high correlation of CO x AOD and a low correlation between FRP with both CO and AOD. Therefore, such emissions in these regions are not generated by forest fires but by industries and vehicular emissions since these are densely populated regions.

The literature reports benefits when the cork powder obtained from industrial by-products is used as the filler of composite laminates. For example, while the fatigue life is insensitive to the presence of cork in the resin, significant improvements are achieved in terms of to low-velocity impact strength. However, in terms of ballistic domain, the literature does not yet report any study about the effect of incorporating powdered cork into resins. Therefore, this study intended to analyse the ballistic behaviour and damage tolerance of Kevlar/epoxy reinforced composites with matrix filled by cork powder. For this purpose, high-velocity impacts were studied on plates of Kevlar bi-directional woven laminates with surfaces of 100 × 100 mm2. It was possible to conclude that the minimum velocity of perforation is 1.6% higher when the cork powder is added to the resin, but considering the dispersion, this small difference can be neglected. In terms of damage areas, they are slightly lower when cork dust is added, especially for velocities below the minimum perforation velocity. Finally, the residual bending strength shows that these composites are less sensitive to impact velocity than the samples with neat resin. In addition to these benefits, cork powder reduces the amount of resin in the composite, making it more environmentally friendly.

In order to create the necessary scientific knowledge for Brazil to understand and deal with the causes and consequences of climate change, the federal government created, in 2007, the Brazilian Network on Global Climate Change Research (Rede CLIMA). Rede CLIMA needs to discuss issues, pose questions, develop methodologies and technological products, find answers, and suggest solutions that are relevant to society. In its first phase, it focused mainly on providing infrastructure and consolidating the sub-networks. Several scientific advances were also achieved, a selection of which are presented in sections focusing on climate modelling, agriculture, energy and water, human development and mobility, biodiversity and ecosystem services, and human health. Now, in its second phase, the objective is to straighten collaboration between sub-networks by means of interdisciplinary projects. It is argued that in order to succeed the Network needs to foster research whose merit is measured not exclusively by academic production.

Modelling the Haemodynamic Response Function (HRF) is a critical step in fMRI studies of brain activity, and it is often desirable to estimate HRF parameters with physiological interpretability. A biophysically informed model of the HRF can be described by a nonlinear time-invariant dynamic system. However, the identification of this dynamic system may leave much uncertainty on the exact values of the parameters. Moreover, the high noise levels in the data may hinder the model estimation task. In this context, the estimation of the HRF may be seen as a problem of model falsification or invalidation, where we are interested in distinguishing among a set of eligible models of dynamic systems. Here, we propose a systematic tool to determine the distinguishability among a set of physiologically plausible HRF models. The concept of absolutely input-distinguishable systems is introduced and applied to a biophysically informed HRF model, by exploiting the structure of the underlying nonlinear dynamic system. A strategy to model uncertainty in the input time-delay and magnitude is developed and its impact on the distinguishability of two physiologically plausible HRF models is assessed, in terms of the maximum noise amplitude above which it is not possible to guarantee the falsification of one model in relation to another. Finally, a methodology is proposed for the choice of the input sequence, or experimental paradigm, that maximizes the distinguishability of the HRF models under investigation. The proposed approach may be used to evaluate the performance of HRF model estimation techniques from fMRI data.

In order to confirm how the presence of the past and the calling of History can be considered characteristics of contemporary novel, as well as the exploring of the “historical possibilities”, we will focus on some aspects of The History of the Siege of Lisbon related to temporal simultaneity or undefinition, efabulation as history’s rewriting, narrator as a decentred authority, etc.

The literature reports benefits when the cork powder obtained from industrial by-products is used as the filler of composite laminates. For example, while the fatigue life is insensitive to the presence of cork in the resin, significant improvements are achieved in terms of to low-velocity impact strength. However, in terms of ballistic domain, the literature does not yet report any study about the effect of incorporating powdered cork into resins. Therefore, this study intended to analyse the ballistic behaviour and damage tolerance of Kevlar/epoxy reinforced composites with matrix filled by cork powder. For this purpose, high-velocity impacts were studied on plates of Kevlar bi-directional woven laminates with surfaces of 100 × 100 mm2. It was possible to conclude that the minimum velocity of perforation is 1.6% higher when the cork powder is added to the resin, but considering the dispersion, this small difference can be neglected. In terms of damage areas, they are slightly lower when cork dust is added, especially for velocities below the minimum perforation velocity. Finally, the residual bending strength shows that these composites are less sensitive to impact velocity than the samples with neat resin. In addition to these benefits, cork powder reduces the amount of resin in the composite, making it more environmentally friendly. [ABSTRACT FROM AUTHOR]

In this paper an experimental investigation on fire retardancy of a new polymer nanocomposite derived from organic montmorillonite and exolit fire retardant in an acrylonitrile- butadiene-styrene copolymer by analyzing the flammability and fire behavior is described. The samples were prepared by melting and mixing nanocomposites and fire retardant in different concentrations in an acrylonitrile-butadiene-styrene base polymer. It was found that using only one component (organic montmorillonite or fire retardant) the burning stops in 10 s on the sample. Confirmation of synergy in flammability by combining both montmorillonite and flame retardants was noticed and is discussed regarding the flame-retardant mechanisms assessed by means of the Limiting oxygen index (LOI), UL 94, and cone-calorimeter methods. The acrylonitrile- butadiene-styrene preparation with 15–20 wt% fire retardant and 1–2 wt% organic montmorillonite reached a UL-94 V-0 classification, contrasting with the pure acrylonitrile- butadiene-styrene and the acrylonitrile-butadiene-styrene with 15 wt% fire retardant and acrylonitrile-butadiene-styrene with 1–2 wt% organic montmorillonite formulations, which completely burned. Finally, the samples showed a very good synergy going to a higher reduction of the peak heat release rate and to a minimum mass reduction, as obtained from cone calorimeter tests. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Brasileira de Agricultura Irrigada - RBAI is the property of Revista Brasileira de Agricultura Irrigada - RBAI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Psicologia: Revista da Associacao Portuguesa Psicologia is the property of Associacao Portuguesa de Psicologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Impact damage is considered the primary cause of in-service delamination in composite materials and promotes significant reduction in residual strength. Non-destructive techniques (NDT) include several methods able to detect the shape and the size of the interior damages without destruction of the structure or component, which is economically advantageous. The aim of this paper is to evaluate the properties after low velocity impacts using an experimental-numerical procedure based on the resonant frequencies. Experimental tests were carried out on [0i, 90i]s (i=2, 3, 4) laminates and the C-Scan technique was used to characterize the internal damage after impact. The resonant technique was applied before and after impact tests, in order to observe the effect of delamination on resonant frequencies. However, the delaminations experimentally observed by C-scan technique were found to have a limited effect on the resonant frequencies. The delaminations deteriorate the composite matrix but its global rigidity is mainly determined by the fibres. [ABSTRACT FROM AUTHOR]

Nowadays composite materials have extensive industrial applications. The thermal conductivity of composites plays an important role in selecting the optimum materials to meet specific design requirements in many applications. For example, requirements for modern composite structural materials for aerospace applications often include high strength, light weight, easy fabrication, low cost, long durability, and stability against radiation damage and chemical reactions. Moreover, for certain applications involving the transport of heat, a tolerable thermal conductivity is necessary [1]. In computer and electronic applications, the heat produced by modern electronic components is greater and more highly concentrated as a result of higher clock speed, greater power, and reduced size. Providing thermal paths for the removal of heat by adding fillers with intrinsically high thermal conductivity in the integrated circuit package components is becoming essential [2]. In the oil industry, the thermal conductivity of rocks must be known to determine heat flow within the earth and to determine the temperatures at depths greater than those reached by drilling. [ABSTRACT FROM AUTHOR]

Fluidized beds are widely used in industry for mixing solid particles with gases or liquids. In most industrial applications, a fluidized bed consists of a vertically-oriented column filled with granular material, and a fluid (gas or liquid) is pumped upward through a distributor at the bottom of the bed. When the drag force of flowing fluid exceeds gravity, particles are lifted and fluidization occurs. A uniform fluidization which is the most desirable regime of operation of industrial fluidized beds, is prone to instabilities. At the fluid flow increases, bubbles of clear fluid are formed at the bottom of the bed and these bubbles travel to the surface. The study of mechanisms of fluid bed instability and the classification of ensuing regimes (slugging, bubbling, etc) has been an active area of research among engineers and physicists. The main conclusion is that the mass flow rate increases linear with the initial fluidization rate. This allows thinking that the mass flow rate between a solid and a real gas could be predicted numerically with a sufficiently high precision: this would make easier the industrial optimization of fluid bed equipments. [ABSTRACT FROM AUTHOR]

A statistical system to predict sea-surface temperature anomalies (SSTAs) over the tropical oceans, with emphasis on the tropical Atlantic, is described. Canonical correlation analysis is used to identify critical sequences of predictor patterns, which tend to evolve into subsequent patterns and which can be used to form a forecast. The results indicate that SST fields over the equatorial Pacific and tropical Atlantic can be a potential predictor of the SSTAs over the tropical Atlantic 3–4 months in advance. The spatial structures of the SSTAs over the tropical Atlantic for the period March–May are well captured by the predictions done with initial conditions from September to February. Model performance is better over the northern tropical Atlantic than over the southern tropical Atlantic, where persistence is hardly beaten. Results of this work can contribute to improve seasonal climate predictions of rainfall anomalies over the northeast Brazil region. Copyright © 2004 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

Polyamide creates high-performance composite materials, which are replacing the traditional epoxy composites in several applications. In this context, exposure to hostile environments is expected. On the other hand, due to the viscoelastic nature of the matrix, these composite materials are prone to stress relaxation. Therefore, the stress relaxation behaviour of glass/polyamide 6 composites was studied considering different fibre directions, as well as exposure to NaOH and HCl solutions. Stress relaxation tests on the bending mode were carried out, and the stress recorded during the loading time (7200 s). All tests were characterized by a stress decrease over time, but laminates with higher fibre angles were more prone to stress relaxation. However, exposure to hostile solutions promoted more significant decreases, where the highest stress relaxation was achieved for alkaline environments with values that were three times higher for laminates with fibres at 0° and around one and half times higher for 45° fibre alignments when compared with the control samples. Finally, the Kohlrausch–Williams–Watts (KWW) model showed that it can be used to predict stress relaxation time, due to the accuracy that was obtained between the experimental and theoretical results. [ABSTRACT FROM AUTHOR]

Este artigo trata de uma pesquisa teórica que tem por objetivo analisar os fundamentos da relação entre a inovação tecnológica e o papel da educação na formação dos trabalhadores. Busca-se identificar como o capital articula inovação, produtividade e projeto educacional. A fase atual do desenvolvimento capitalista, caracterizada pela acumulação flexível, tem na intensificação acentuada de inovação os seus fundamentos estruturais. O aumento da capacidade de inovação possibilita para a empresa e para o país, segundo o empresariado industrial, a condição de competitividade no mercado internacional, isto porque, entre outros fatores, ela proporciona um salto de produtividade. Trata-se de compreender como esta vinculação entre educação e capital se dá no contexto dos novos paradigmas produtivos, que têm na inovação constante o seu principal pilar de sustentação.

ABSTRACT Information on the effects of climate conditions on the survival of species grown in semi-arid regions is essential and at the same time scarce, especially regarding rustic species such as West Indian gherkin (Cucumis anguria L.). Thus, this study aimed to evaluate germination, growth and biochemical alterations in C. anguria seeds under water stress and different temperature regimes. The experimental design was completely randomized, in 5 x 5 factorial scheme, composed of five osmotic potentials (0.0; -0.1; -0.2; -0.3 and -0.4 MPa) and four temperatures (20; 25; 30 °C and alternating temperatures of 20-30 ºC), with each treatment composed of four replicates of 50 seeds. The seeds were sown on paper towel (Germitest®) and germinated in Biochemical Oxygen Demand (B.O.D.) germinators, under 8-h photoperiod. Germination percentage, germination speed index, mean time of germination, seedling length and contents of chlorophylls, carotenoids, proline, free amino acids and free sugars were determined along the experiment. Decrease in osmotic potential reduced germination, growth and contents of chloroplast pigments of C. anguria seedlings, but was more drastic at levels lower than -0.2 MPa. Low temperatures intensify the effects of water stress on the germination of C. anguria seeds. The synthesis of protecting osmolytes increased in C. anguria seedlings but these components did not promote efficient osmotic adjustment in their initial development stage.

The aim of this work is to characterize the rolling and rolling-sliding contact fatigue failure mechanisms on the 32CrMoV13 nitrided steel. During rolling contact fatigue tests (RCF), two general features were observed: specimens presenting short lives and rough and sharpened spalling damage and specimens presenting long lives and only microspalling marks. It was possible to determine a contact fatigue limit of 3 GPa. During rolling-sliding contact fatigue tests (RSCF), a clearly different behaviour between the two specimens in contact has been observed: the driver shows circumferential and inclined cracks and only inclined cracks appear in the follower. This behaviour can be understood if the effect of the residual stress state in near-surface layers is considered. Before RCF tests, the residual stresses are compressive in all near-surface layers. After RCF tests, strong residual stress relaxation and even reversing behaviour was observed in the axial direction, which facilitates the surface crack initiation in the circumferential direction at rolling track borders.

A propagação assexuada das Spondias pelo método de estaquia apresenta fortes limitações, não dispondo de tecnologias para a produção comercial de mudas, principalmente quanto ao uso de enraizadores e substratos que potencialize seu desenvolvimento. Diante disso, o objetivo deste trabalho foi avaliar o enraizamento de estacas de cajaraneira sob doses de ácido indolbutírico (AIB) e em diferentes substratos. O delineamento experimental foi o de blocos casualizados, em esquema fatorial 3 × 5, três substratos (comercial - tropstrato; solo+esterco bovino [1v:1v]; esterco bovino+esterco de galinha [1v:1v]) e com cinco concentrações de AIB (0, 600, 1.200, 1.800 e 2.400 mg L-1), usando quatro repetições e 10 estacas por unidade experimental. Aos 115 dias após a montagem do experimento, foram avaliados: número de folhas, de folíolos, de brotos e de raízes; comprimento do broto, das folhas e da raiz; diâmetro do broto; número e comprimento de raízes; porcentagens de estacas calejadas, estacas vivas, estacas brotadas com raiz e estacas brotadas; massa seca das folhas (g), dos brotos (g), das raízes (g) e total (g). Diante dos resultados, observou-se que o regulador de crescimento (AIB) não influenciou o enraizamento de estacas lenhosas de cajaraneira e que o substrato comercial tropstrato proporcionou maior enraizamento de estacas, seguido do substrato solo+esterco bovino (1v:1v). O substrato esterco bovino+esterco de galinha (1v:1v) mostrou-se inadequado para a produção de mudas de cajaraneira propagadas por estaquia.

Os frutos de figueira apresentam uma vida útil relativamente curta, em virtude de sua frágil estrutura e seu elevado metabolismo, o que exige enormes cuidados em seu armazenamento. Objetivou-se com este trabalho avaliar os atributos físico-químicos nos diferentes tempos de armazenamento na conservação pós-colheita de figueira cv. Roxo de Valinhos. Utilizou-se delineamento experimental inteiramente casualizado, em esquema fatorial 5 x 3 (5 tempos de armazenamento: 0, 4, 8, 12, 16 dias; e 3 pontos de colheita: 50, 75 e 100% maduros), com quatro repetições e 8 frutos por tratamento. Os figos foram armazenados em câmara fria, em temperatura de 10 ± 2°C e 80-90% de umidade relativa. Estes fatores se mostraram como uma eficiente alternativa para manter a qualidade dos frutos por até 4 dias para as características de massa fresca e vitamina C, enquanto o teor de sólidos solúveis (°Brix) teve seus melhores valores aos 16 dias de armazenamento. O estádio de maturação III obteve maior comprimento e diâmetro, bem como menor perda de massa fresca e firmeza dos frutos.

Amburana cearensis, conhecida como cumaru, é uma espécie presente em todo bioma caatinga, sendo recomendada para recuperação de áreas degradadas e usos fitoterápicos. O objetivo do presente trabalho foi determinar os níveis de tolerância ao estresse hídrico na germinação e no crescimento de plântulas de cumaru em função da massa das sementes. Inicialmente as sementes foram pesadas e separadas em três classes (leves, médias e pesadas), sendo estas submetidas ao estresse hídrico, utilizando soluções de Polietilenoglicol 6000, em diferentes potenciais (0,0; -0,2; -0,4; - 0,6; -0,8 e -1,0 MPa) e colocadas para germinar na temperatura de 30 °C em câmaras de germinação. O delineamento experimental foi inteiramente casualizado em esquema fatorial 3 x 6 (classes de massa x potencial hídrico). Para a avaliação da germinação, foram determinados a primeira contagem, porcentagem final e índice de velocidade de germinação, enquanto para a avaliação do crescimento das plântulas determinou-se o comprimento e massa seca do epicótilo e do eixo raiz + hipocótilo e a razão parte aérea/raiz. Os dados foram submetidos ao teste de normalidade e quando se apresentaram normais, realizou-se análise de variância, comparação de médias e regressão. O decréscimo do potencial hídrico prejudica a germinação e o crescimento de plântulas oriundas de sementes médias e pesadas em relação às leves, sendo a partir do potencial -0,6 MPa uma condição estritamente limitante na formação de plântulas normais de A. cearensis.

The objective of this work was to study the seed germination and seedling growth of A. cearensis (Allemão) A. C. Sm. influenced by seed weight and under different temperature and light conditions. Seeds were individually weighed and divided into three weight classes (light, medium and heavy), and each was subjected to germination tests under two light conditions (presence or absence) and six temperature regimes (20, 25, 30, 35, 40, and 20-30°C). The experiment was established with a completely randomized design in a split-split plot arrangement with four replicates. We determined the first count, final germination percentage and germination speed index. To assess seedling growth, the length and dry mass of the epicotyl and root + hypocotyl axis were also determined. The data were subjected to Tukey’s test (p ≤ 0.05). The optimal conditions for seed germination occurred at a temperature of 30°C, with light and medium seeds showing greater vigour. Temperatures of 35 and 40°C were detrimental to the growth of the species, whereas the best conditions occurred with light and medium seeds at temperatures of 25 and 30°C in the presence of light.

O conhecimento dos aspectos que envolvem todo o mecanismo do processo de germinação de sementes em espécies florestais ainda se encontra muito aquém em comparação com as espécies cultivadas. Objetivou-se estudar a influência da localização da semente no fruto sobre a germinação e crescimento de plântulas de tamboril (Enterolobium contortisiliquum) sob dois regimes de temperatura. Foram separadas as sementes das regiões proximal, central e distal do fruto. As sementes de cada região foram submetidas aos testes de primeira contagem, porcentagem final e índice de velocidade de germinação, em dois regimes de temperatura (25 °C constante e 20-30 °C alternados), além do envelhecimento acerado. As plântulas provenientes desses testes foram analisadas pelas determinações do comprimento e massa seca da parte aérea, raiz e total. O experimento foi conduzido em delineamento inteiramente casualizado, seguindo um esquema fatorial 3x2 (três regiões e duas temperaturas) com quatro repetições. Os dados com distribuição normal foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey (5%); quando não normal utilizou-se o teste não paramétrico de Mann-Whitney (5%). Houve interação dos fatores para o índice de velocidade de germinação, comprimento total, massa seca total e massa seca da parte aérea das plântulas. Não se observou diferenças entre as localizações para as variáveis de avaliação das plântulas. Quanto à germinação, sob 25 °C as sementes da região distal do fruto germinaram mais rapidamente. Independente dos tratamentos a porcentagem de germinação foi sempre superior a 95%, mesmo quando envelhecidas. Conclui-se que não há diferença entre as temperaturas de 25 e 20-30 °C para a germinação de tamboril; que a localização das sementes no fruto não influencia na formação das plântulas; e que a velocidade de germinação e o crescimento das plântulas provenientes de sementes das regiões proximal e distal são mais sensíveis às mudanças de temperatura.

Na região semiárida do Nordeste do Brasil, em que a água é um fator limitado e escasso, faz-se necessário o aproveitamento de águas residuárias tratadas com possibilidades de assegurar e incrementar a produção agrícola. A sua utilização na irrigação de mudas frutíferas, poderá representar uma alternativa promissora na produção de mudas de boa qualidade, criando assim, uma opção para o uso dessa água, não simplesmente pelo aporte de nutriente, mas, sobretudo por contribuir com a preservação de meio ambiente. Com esse intuito, foi conduzido um experimento com objetivo de aproveitar o efluente de esgoto tratado na fertirrigação de mudas de Maracujazeiro amarelo. O delineamento experimental adotado foi o de blocos casualizados com cinco tratamentos e quatro repetições. Os tratamentos constituíram na aplicação de 100% de água de abastecimento (AA) - T1 (testemunha); 75% água de abastecimento (AA) + 25% de efluente doméstico (ED) - T2; 50% AA + 50% ED - T3; 25% AA + 75% ED - T4 e 100% do efluente doméstico - T5. Foram avaliados o comprimento da parte aérea; número de folhas definitivas; área foliar; massa fresca e seca da parte aérea, do sistema radicular e total. Para a produção de mudas de maracujazeiro amarelo, a aplicação com o efluente doméstico tratado na concentração de 75% e 100% promoveu um melhor desempenho em termos de crescimento das mudas em todas as variáveis analisadas.

A água é uma substância necessária a diversas atividades humanas, além de constituir componente fundamental da biosfera e ser solvente universal, sendo essencial à vida. Objetivou-se, com esta pesquisa avaliar a influência da irrigação com água de diferentes salinidades utilizando rejeito salino, sobre a produção de mudas de pinha em experimento conduzido em sacos plásticos sob condições de campo na comunidade Boa Fé, zona rural do município de Mossoró-RN, entre os meses de outubro de 2010 e fevereiro de 2011. Adotou-se o delineamento experimental em blocos inteiramente casualizados, com três tratamentos e cinco repetições, considerando-se como unidade experimental um total de 50 mudas. Os tratamentos constituíram da mistura de água do sistema de abastecimento (AB) da comunidade (água dessalinizada) com água do rejeito do processo dessalinizante (RD), compondo os seguintes tratamentos: T1(100% AB - controle), T2(50% AB + 50% RD) e T3(100% RD) com suas respectivas condutividades elétricas, (1,25; 4,79; e 8,47 dS m-1). A taxa de crescimento relativo à altura de planta, diâmetro do caule, número de folhas, área foliar e a massa seca e fresca da parte aérea da pinha, são afetados exponencialmente e negativamente pela salinidade da água de irrigação a partir de 1,25 dS m-1, mas não impedindo que as plantas atingissem condições necessárias para serem transplantadas.

Com o objetivo de testar fonte e dose de nitrogênio para a produção de porta-enxertos de pitombeira foi conduzido o experimento em viveiro de produção de mudas, coberto com tela de 50% de sombra, da Universidade Federal Rural do Semiárido (UFERSA), no período de agosto de 2009 a julho de 2010, sendo testadas duas fontes de nitrogênio (uréia e sulfato de amônio) e cinco doses (0; 400; 800; 1.600 e 3.200 mg dm3 de N) no substrato, aplicadas em cobertura, parceladas em 5 vezes. O delineamento experimental utilizado foi o de blocos ao acaso em esquema fatorial 2 x 5, onde utilizou-se duas fontes e cinco doses de nitrogênio, com dez tratamentos, 4 repetições e dez plantas por parcela. Foram avaliados: número de folhas, diâmetro do colo (mm), altura da planta (cm), comprimento da raiz (cm), matéria seca da parte aérea (g/muda), matéria seca da raiz (g/muda), matéria seca total (g/muda) e relação matéria seca da parte aérea e matéria seca da raiz. A adubação nitrogenada promoveu um incremento na produção de porta-enxertos de pitombeira, independente da fonte. O maior valor da massa seca da parte aérea de porta-enxertos de pitombeira foi de 2,1 g porta-enxertos-1, quando aplicou-se 613,6 mg dm-3 de nitrogênio.

O objetivo deste trabalho foi avaliar diferentes compostos orgânicos na composição de substratos para a formação de mudas de Cucumis melo var. cantalupensis Naud. O delineamento experimental utilizado foi de blocos casualizados, com cinco tratamentos e quatro repetições, sendo utilizadas 18 sementes por parcela, as mudas foram conduzidas em bandejas de polietileno com 128 células. Os tratamentos utilizados foram os substratos: 1-Solaris®; 2- Arisco; 3- Solaris® + esterco caprino (1:1); 4- Arisco + esterco caprino (1:1); 5- Polifértil® e 6- Polifértil® + arisco (1:1). As variáveis analisadas foram: porcentagem de germinação, índice de velocidade deemergencia (IVE), comprimento da parte aérea da plântula (cm) e comprimento do sistema radicular (cm), matéria seca da parte aérea e das raízes. Os dados demonstram que a mistura mais eficiente para a formação de mudas de meloeiro foi, Solaris® + esterco bovino (1:1).

Para obtenção de mudas de boa qualidade há a necessidade de encontrar alternativas mais baratas e sustentáveis para a produção da mesma, bem como de informações sobre o uso de substratos alternativos. Assim, diante do exposto, objetivou-se com este trabalho avaliar a utilização de substratos alternativos na produção de mudas, em viveiro, de maracujazeiro amarelo em bandejas. O delineamento experimental adotado foi o de blocos completos casualizados com seis tratamentos e quatro repetições e os dados foram submetidos à análise de variância e os posteriormente submetidos ao teste de regressão. Os tratamentos constaram de substratos (S1 = Solaris®; S2 = solo; S3 = 50% de vermiculita + 50% de solo; S4 = 50% de solo + 50% de esterco bovino; S5 = 50% de solo + 50% de esterco caprino; S6 = 50% de Solaris® + 50% de esterco bovino). Foram feitas as seguintes avaliações: número de folhas; diâmetro do colo; comprimento da parte aérea, do sistema radicular e da muda; massa seca da parte aérea, do sistema radicular e total; relação entre massa seca da parte aérea e do sistema radicular; índice de qualidade de Dickson. Para a produção de mudas de maracujazeiro amarelo vigorosas, em bandeja, pode ser utilizado o substrato alternativo composto por 50% solo + 50% esterco bovino (S4) ou 50% solo + 50% esterco caprino (S5) em substituição aos substratos comerciais.

A escassez de recursos é um fator limitante ao desenvolvimento econômico e social de uma região. Diante desse fato, o objetivo desse trabalho foi avaliar o índice de velocidade de germinação e percentual germinativo, bem como o desenvolvimento de mudas do meloeiro (Cucumis melo L.) irrigada com água de abastecimento combinada com água residuária de origem doméstica pré-tratada. O delineamento experimental utilizado foi o de blocos completos casualizados, com cinco tratamentos e cinco repetições. Os tratamentos constaram de: T1 (100% água residual); T2 (75% água residual = AR + 25% água de abastecimento = AB); T3 (50% AR + 50% AA); T4 (25% AR + 75% AA) e T5 (100% AA). Foram feitas as seguintes avaliações: Percentual germinativo, número de plantas e índice de velocidade de emergência durante sua germinação e, posteriormente, número de folhas; comprimento da parte aérea e sistema radicular; diâmetro do caule; área foliar; massa seca da parte aérea, do sistema radicular e total. Assim, constatou-se no presente trabalho que todas as concentrações de água residuária podem ser utilizadas, sendo que o uso da mesma proporcionou uma produção de mudas de melão mais vigorosas quando utilizados os tratamento T1 e T2 composto por 100% e 75% de água residuária, respectivamente.

RESUMO - A irrigação se torna a prática mais segura para garantir a produção agrícola, mas para suprir a demanda da água precisa-se implantar uma política racional de reutilização de águas. Com esse intuito foi instalado e conduzido um experimento aproveitando a água residuária oriunda de um projeto de pesquisa para o desenvolvimento de mudas de Melancia ‘Crimson sweet’. O delineamento experimental adotado foi o de blocos completos casualizados com cinco tratamentos e quatro repetições e os dados foram submetidos à análise de variância pelo teste F, e suas médias comparadas pelo teste de Scott e Knott, a 5% de probabilidade. Os tratamentos constaram de: T1 (100% água residual); T2 (75% A. Residual + 25% A. de Abastecimento); T3 (50% A.R + 50% A.A); T4 (25% A.R + 75% A.A) e T5 (100% A.A). Foram feitas as seguintes avaliações: percentual de germinação; índice de velocidade de emergência; número de folhas definitivas; comprimento da parte aérea e do sistema radicular; massa fresca e seca da parte aérea, do sistema radicular e total. O melhor desenvolvimento das mudas de Melancia ocorreu com aplicação de água residuária quando utilizados os tratamentos T1 e T2 composto por 100% e 75% de água residuária, respectivamente. Palavras-chave: Citrullus lanatus, reuso, fertirrigação.

O presente trabalho teve por objetivo avaliar a utilização de substratos alternativos utilizando o capítulo de girassol na produção de mudas de mamoeiro “Sunrise solo” em bandejas de poliestireno. O delineamento experimental adotado foi o de blocos casualizados com quatro tratamentos e cinco repetições, sendo os resultados submetidos à análise de variância e posteriormente submetidos ao teste Scott-Knott a 5% de probabilidade. Os tratamentos constaram de 4 (quatro) substratos (S1 = Plantmax®; S2 = 50% de capítulo de girassol + 50% de esterco caprino; S3 = 25% de capítulo de girassol + 75% de esterco caprino; S4 = 50% de capítulo de girassol + 50% de Plantmax®). Foram feitas as seguintes avaliações: número de folhas; diâmetro do colo; comprimento da parte aérea, do sistema radicular e da muda; massa seca da parte aérea, do sistema radicular e total; relação entre massa seca da parte aérea e do sistema radicular; índice de qualidade de Dickson. Para a produção de mudas de mamoeiro “Sunrise solo” em viveiro, pode ser utilizado o substrato alternativo composto por 25% de capítulo de girassol + 75% de esterco caprino.

RESUMO - O objetivo do presente trabalho foi reduzir o tempo de germinação e desenvolvimento inicial em sementes de Tamarindo (Tamarindus indica L.). Utilizou-se o delineamento inteiramente casualizado com cinco tratamentos e quatro repetições. Os tratamentos utilizados foram: T1 testemunha, T2 embebido em ácido sulfúrico por 15min, T3 embebido em ácido acético (vinagre) por 20min, T4 embebido em álcool por 15min e T5 colocados em água quente a 70°C por 15 min. Cada parcela foi constituída por uma amostra de 33 sementes. As características avaliadas foram: altura de plântula, comprimento de raiz, percentagem de germinação e índice de velocidade de germinação, matéria seca da parte aérea e sistema radicular. As sementes embebidas em ácido sulfúrico por 15 minutos foram as que proporcionaram maior percentagem de germinação e índice de velocidade de germinação. Palavras-chave: Tamarindo, germinação, propagação.