339 research outputs found

    Pyrolysis final temperature effects on biochar stability.

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    Pyrolysis technology can be used for producing biochar and bio-oil simultaneously, as an effective and sustainable mean to produce renewable bioenergy and a carbon rich soil amendment that can be used for carbon sequestration and agronomic benefits. However, pyrolysis products yields and biochar stability are strongly affected by the feedstock and pyrolysis variables, especially the final temperature. This study was carried out to evaluate the effect of pyrolysis final temperature on biochar stability after thermochemical oxidation. For this experiment, two species of hardwood and two species of softwood with particle size between 0.5 and 2.0 mm were pyrolized at five different final temperatures (350, 400, 450, 500 and 550°C) for 60 min at an muffle furnace with limited supply of O2. Thermochemical oxidation was performed for the solid products (biochar). As pyrolysis final temperature increased, biochar stability increased as well, indicating that these materials would be more resistant to degradation when applied into soil

    Biochar stable fraction quantification by thermochemical oxidation and assessement by 13C-NMR spectrocopy.

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    Although biochar is often regarded lized into carbon dioxide. However, it is unclear how much of this material is rapidly oxidized, that is, how much remain in the soil for NQPIGTRGTKQFU'ƑQTVUJCXGDGGPWPFGTVCMGP to develop methodologies to quantify the stable fraction present in biochar, quickly, easily reproducible, and that somehow represents TGCN?GNFEQPFKVKQPU6JGTGHQTGVJGCKOQHVJKU UVWF[YCUVQGXCNWCVGVJGGƑGEVQHFKƑGTGPV R[TQN[UKU?PCNVGORGTCVWTGUQPVJGUVCDKNKV[QH biochar produced from Eucalyptus dunnii wood by analyzing biochar samples before and after a thermo-chemical oxidation using 13 C NMR spec- troscopy. Stable-C fraction increased as higher R[TQN[UKU?PCNVGORGTCVWTGYCU6JGTOQEJGOical oxidation was responsible for removing labile structures still present as well as aromatic structures less resistant to degradation. Thermo-chemical oxidation was also responsible for the functionalization of biochars, being this ef- HGEVOKNFGTCUJKIJGTR[TQN[UKU?PCNVGORGTCVWTG was. The balance between C storage (Stable-C HTCEVKQPCPFCITQPQOKEDGPG?VU HWPEVKQPCNK\Ction) of biochar should be carefully evaluated, as its characteristics can vary depending on the conditions by which it was produced

    Alternative transmission routes in the malaria elimination era: an overview of transfusion-transmitted malaria in the Americas

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    Submitted by Janaína Nascimento ([email protected]) on 2019-02-21T11:59:00Z No. of bitstreams: 1 ve_Alho_Regina_etal_INI_2017.pdf: 1190158 bytes, checksum: 8937322faefa31c89eb1bbd2f7d134a3 (MD5)Approved for entry into archive by Janaína Nascimento ([email protected]) on 2019-02-25T11:34:33Z (GMT) No. of bitstreams: 1 ve_Alho_Regina_etal_INI_2017.pdf: 1190158 bytes, checksum: 8937322faefa31c89eb1bbd2f7d134a3 (MD5)Made available in DSpace on 2019-02-25T11:34:33Z (GMT). No. of bitstreams: 1 ve_Alho_Regina_etal_INI_2017.pdf: 1190158 bytes, checksum: 8937322faefa31c89eb1bbd2f7d134a3 (MD5) Previous issue date: 2017Universidade do Estado do Amazonas. Manaus, AM, Brasil / Fundação de Hematologia e Hemoterapia do Amazonas. Manaus, AM, Brasil.Fundação de Medicina Tropical Dr. Heitor Vieira Dourado. Manaus, AM, Brasil.Universidade do Estado do Amazonas. Manaus, AM, Brasil / Fundação de Medicina Tropical Dr. Heitor Vieira Dourado. Manaus, AM, Brasil.Fundação de Hematologia e Hemoterapia do Amazonas. Manaus, AM, Brasil.Universidade do Estado do Amazonas. Manaus, AM, Brasil.Universidade do Estado do Amazonas. Manaus, AM, Brasil / Fundação de Medicina Tropical Dr. Heitor Vieira Dourado. Manaus, AM, Brasil.Sem afiliação.Fundação Oswaldo Cruz. Instituto Nacional de Infectologia Evandro Chagas. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto de Pesquisas Leônidas e Maria Deane. Manaus, AM, Brasil.Universidade do Estado do Amazonas. Manaus, AM, Brasil / Fundação de Medicina Tropical Dr. Heitor Vieira Dourado. Manaus, AM, Brasil.Universidade do Estado do Amazonas. Manaus, AM, Brasil / Fundação de Medicina Tropical Dr. Heitor Vieira Dourado. Manaus, AM, Brasil / Fundação Oswaldo Cruz. Instituto de Pesquisas Leônidas e Maria Deane. Manaus, AM, Brasil.Background: Transfusion-transmitted (TT) malaria is an alternative infection route that has gained little attention from authorities, despite representing a life-threatening condition. There has been no systematic review of this health problem in American countries. The aim of this study was to describe the clinical and epidemiological characteristics of TT malaria in the Americas and identify factors associated with lethality based on the studies published in the literature. Methods: Potentially relevant papers in all languages were retrieved from MEDLINE and LILACS. Additional articles were obtained from reviews and original papers. Publications on screening of candidate blood donors and on surveillance of TT malaria cases were included. Odds ratios with respective 95% confidence intervals (95% CI) were calculated. Epidemiological characteristics of blood donors of TT malaria cases, including a pooled positivity of different tests for malaria diagnosis, were retrieved. Results: A total of 63 publications regarding TT malaria from seven countries were included, from 1971 to 2016. A total of 422 cases of TT malaria were recorded. Most TT malaria cases were in females (62.0%) and 39.5% were in the ≥61 years-old age group. About half of all cases were from Mexico (50.7%), 40.3% from the United States of America (USA) and 6.6% from Brazil. Gyneco-obstetrical conditions (67.3%), surgical procedures (20.6%) and complications from neoplasias (6.1%) were the most common indications of transfusion. Packed red blood cells (RBCs) (50.7%) and whole blood (43.3%) were the blood products mostly associated with TT malaria. Cases were mostly caused by Plasmodium malariae (58.4%), followed by Plasmodium vivax (20.7%) and Plasmodium falciparum (17.9%). A total of 66.6% of cases were diagnosed by microscopy. Incubation period of 2–3 weeks was the most commonly observed (28.6%). Lethality was seen in 5.3% of cases and was associated with living in non-endemic countries, P. falciparum infection and concomitant neoplastic diseases. Conclusion: There is an important research and knowledge gap regarding the TT malaria burden in Latin American countries where malaria remains endemic. No screening method that is practical, affordable and suitably sensitive is available at blood banks in Latin American countries, where infections with low parasitaemia contribute greatly to transmission. Lethality from TT malaria was not negligible. TT malaria needs to be acknowledged and addressed in areas moving toward elimination

    Utilização de biochar para mitigação das emissões de óxido nitroso do solo.

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    Com o avanço das mudanças climáticas ocasionadas pelo aquecimento global, faz-se necessário a busca por soluções que visem mitigar as emissões de gases de efeito estufa. O presente estudo objetivou avaliar o uso de biochar como prática para mitigar as emissões de óxido nitroso (N2O) gerado pela aplicação de fertilizante nitrogenado no solo. O biochar pode ser uma alternativa com potencial para mitigar as emissões de N2O provenientes do solo e o presente trabalho indica que doses acima de 6 Mg ha-1 trariam efeitos positivos

    Working memory training restores aberrant brain activity in adult attention-deficit hyperactivity disorder

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    The development of treatments for attention impairments is hampered by limited knowledge about the malleability of underlying neural functions. We conducted the first randomized controlled trial to determine the modulations of brain activity associated with working memory (WM) training in adults with attention-deficit hyperactivity disorder (ADHD). At baseline, we assessed the aberrant functional brain activity in the n-back WM task by comparing 44 adults with ADHD with 18 healthy controls using fMRI. Participants with ADHD were then randomized to train on an adaptive dual n-back task or an active control task. We tested whether WM training elicits redistribution of brain activity as observed in healthy controls, and whether it might further restore aberrant activity related to ADHD. As expected, activity in areas of the default-mode (DMN), salience (SN), sensory-motor (SMN), frontoparietal (FPN), and subcortical (SCN) networks was decreased in participants with ADHD at pretest as compared with healthy controls, especially when the cognitive load was high. WM training modulated widespread FPN and SN areas, restoring some of the aberrant activity. Training effects were mainly observed as decreased brain activity during the trained task and increased activity during the untrained task, suggesting different neural mechanisms for trained and transfer tasks

    The modulation of auditory novelty processing by working memory load in school age children and adults: a combined behavioral and event-related potential study

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    <p>Abstract</p> <p>Background</p> <p>We investigated the processing of task-irrelevant and unexpected novel sounds and its modulation by working-memory load in children aged 9-10 and in adults. Environmental sounds (novels) were embedded amongst frequently presented standard sounds in an auditory-visual distraction paradigm. Each sound was followed by a visual target. In two conditions, participants evaluated the position of a visual stimulus (0-back, low load) or compared the position of the current stimulus with the one two trials before (2-back, high load). Processing of novel sounds were measured with reaction times, hit rates and the auditory event-related brain potentials (ERPs) Mismatch Negativity (MMN), P3a, Reorienting Negativity (RON) and visual P3b.</p> <p>Results</p> <p>In both memory load conditions novels impaired task performance in adults whereas they improved performance in children. Auditory ERPs reflect age-related differences in the time-window of the MMN as children showed a positive ERP deflection to novels whereas adults lack an MMN. The attention switch towards the task irrelevant novel (reflected by P3a) was comparable between the age groups. Adults showed more efficient reallocation of attention (reflected by RON) under load condition than children. Finally, the P3b elicited by the visual target stimuli was reduced in both age groups when the preceding sound was a novel.</p> <p>Conclusion</p> <p>Our results give new insights in the development of novelty processing as they (1) reveal that task-irrelevant novel sounds can result in contrary effects on the performance in a visual primary task in children and adults, (2) show a positive ERP deflection to novels rather than an MMN in children, and (3) reveal effects of auditory novels on visual target processing.</p

    Sub-grid modeling of pitch-angle diffusion for ion-scale waves in hybrid-Vlasov simulations with Cartesian velocity space

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    Numerical simulations have grown to play a central role in modern sciences over the years. The ever-improving technology of supercomputers has made large and precise models available. However, this accuracy is often limited by the cost of computational resources. Lowering the simulation's spatial resolution in order to conserve resources can lead to key processes being unresolved. We have shown in a previous study how insufficient spatial resolution of the proton cyclotron instability leads to a misrepresentation of ion dynamics in hybrid-Vlasov simulations. This leads to larger than expected temperature anisotropy and loss-cone shaped velocity distribution functions. In this study, we present a sub-grid numerical model to introduce pitch-angle diffusion in a 3D Cartesian velocity space, at a spatial resolution where the relevant wave-particle interactions were previously not correctly resolved. We show that the method is successfully able to isotropize loss-cone shaped velocity distribution functions, and that this method could be applied to simulations in order to save computational resources and still correctly model wave-particle interactions.Peer reviewe
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