Análise de fluxo de carbono, nitrogênio e fósforo e avaliação de impactos ambientais em aterro sanitário e na compostagem de resíduos sólidos urbanos

No Brasil, quase 60% dos resíduos sólidos urbanos (RSU) são destinados a aterros sanitários. No estado do Rio Grande do Sul este número é de aproximadamente 70%. Em Porto Alegre, o Aterro Sanitário da Extrema (ASE) foi o primeiro a operar de 1997 a 2002. Desde o início da sua operação, em 1997, até hoje, a geração de lixiviado no ASE continua a ser monitorada. Após 12 anos do seu encerramento o aterro ainda apresentava elevado potencial poluidor devido, especialmente, às suas concentrações remanescentes de matéria carbonácea biodegradável representada pelas médias de 459,25 mg DBO5/L e 1187,5 mg DQO/L, e nitrogênio com uma média de 1103 mg N/L. Os resíduos e, consequentemente os gases e o lixiviado do aterro são compostos por substâncias, destacando-se o nitrogênio (N), o fósforo (P) e o carbono (C). A fim de avaliar a recuperação e reutilização destes nutrientes, é necessário um estudo mais detalhado dos sistemas de gerenciamento de resíduos e das diferentes rotas de determinadas substâncias em um aterro sanitário. A Análise de Fluxo de Substâncias (AFS) é uma ferramenta útil para determinar os fluxos destes nutrientes em um aterro sanitário. Este trabalho teve por objetivo aplicar a ferramenta de AFS no ASE no período de 1997 a 2002 e na compostagem destes resíduos para avaliar os fluxos de carbono, nitrogênio e fósforo. Além disso, estimou-se a geração de gases e os potenciais impactos ambientais nos dois sistemas. Para a AFS utilizou-se o programa STAN 2.6 e para a avaliação de impactos ambientais a metodologia CML-IA. De 1997 a 2002 o ASE recebeu 231.417 toneladas de carbono, das quais aproximadamente 98.982,8 toneladas foram perdidas através de emissões atmosféricas e do lixiviado, permanecendo 132.434,2 toneladas aterradas. O ASE recebeu 5.531,8 toneladas de nitrogênio, perdeu 4.290 toneladas e acumulou 1.061,5 toneladas. Quanto ao fósforo das 696,15 toneladas aterradas, apenas 6,47 toneladas foram perdidas em 20 anos. O potencial de aquecimento global do ASE foi de 2.090.628 t CO2 eq., de acidificação 6.761,5 t SO4 eq. e o potencial de eutrofização 1.479 t PO4 eq. Na compostagem as perdas de carbono variaram de 35.806 a 78.546 toneladas e as de nitrogênio de 759,96 a 2.004 toneladas. Quanto aos potenciais impactos ambientais na compostagem o potencial de aquecimento global variou de 171.066,87 a 392.959,51 t CO2 eq., de acidificação variou de 0,06 a 0,16 t SO4 eq. e o potencial de eutrofização de 339,70 a 895,99 t PO4 eq. A destinação da matéria orgânica ou mesmo da fração rapidamente degradável (RD) para um sistema de compostagem vai de encontro à Política Nacional de Resíduos Sólidos (PNRS) a qual determina que aterros sanitários recebam apenas rejeitos e não mais matéria orgânica. Tal prática evitaria o desperdício de substâncias já que estas deixam de ser apenas aterradas para encontrarem um novo uso como composto orgânico.In Brazil, almost 60% of the urban solid wastes (USW) are sent to sanitary landfills. In the state of Rio Grande do Sul (RS) this number is approximately 70%. In Porto Alegre, the Extrema Sanitary Landfill (ASE- Aterro Sanitário da Extrema) was the first to operate from 1997 to 2002. Leachate generation at ASE has been monitored from the beginning of its operation in 1997 until today. Twelve years after it was closed down the landfill still presented a high polluting potential due, mainly, to its remaining concentrations of biodegradable carbon material represented by the averages of 459.25 mg BOD5/L and 1187.5 mg COD/L, and nitrogen with an average of 1103 mgN / L. The wastes, and consequently the gases and the landfill leachate, are composed by substances, mainly nitrogen (N), phosphorus (PH) and carbon ( C ). In order to evaluate the recovery and reuse of these nutrients, it is necessary to perform a more detailed study of the waste management systems and the different routes taken by certain substances in a sanitary landfill. Substance Flow Analysis (SFA) is a useful tool to determine the flows of these nutrients there. The objective of this study was to apply the SFA tool at ASE during the period from 1997 to 2002, and on composting these wastes to evaluate the carbon, nitrogen and phosphorus flows. In addition, the generation of gases and potential environmental impacts on both systems were estimated. Program STAN 2.6 was used for SFA, and the CML-IA methodology was used to evaluate environmental impacts. From 1997 to 2002, ASE received 231,417 tons of carbon, of which approximately 98,982.8 tons were lost through atmospheric emissions and leachate, and 132,434.2 tons remained in the landfill. ASE received 5,531.8 tons of nitrogen, lost 4,290 tons and accumulated 1,061.5 tons. As to phosphorus, of the 696.15 tons landfilled only 6.47 tons were lost in 20 years. The global warming potential of ASE was 2,090,628 t CO2 eq, of acidification 6,761.5 t SO4 eq and the potential for eutrophication was 1,479 t PO4 eq. In composting, the carbon losses varied from 35,806 to 78,546 tons and those of nitrogen from 759.96 to 2,004 tons. As to the potential environmental impacts in composting, the potential for global warming varied 171,066.87 to 392,959.51 t CO2 eq, of acidification which varied from 0.06 to 0.16 t SO4 eq and the potential for eutrophication from 339.70 to 895.99 t PO4 eq. The disposal of the organic matter or even of the rapidly degradable fraction (RD) to a composting system is in accordance with the National Policy for Solid Wastes (PNRS-Política Nacional de Resíduos Sólidos) which determines that sanitary landfills should receive only rejects but no longer organic matter. This practice would avoid wasting substances, since they no longer will be landfilled but find a new use as organic compost

Caracterização de uma estação de tratamento de esgoto por zona de raízes utilizando variáveis abióticas e microbiológicas

Wastewater root zone treatment systems are constituted of a filter bed planted with emergent macrophytes. A low cost technology with treatment potential proven in numerous studies, the root zone Wastewater Treatment Station (WTS) have great potential to solve the problem of lack of wastewater collection and treatment in small communities. This study aimed to characterize a root zone WTS with vertical flow on the basis of abiotic and microbiological variables. Through the technique of plate count and the multiple tube method was possible to estimate the density of total fungi, heterotrophic bacteria, total coliforms, Escherichia coli, nitrate-reducing bacteria, denitrifying bacteria and sulfate-reducing bacteria in the different strata of the system. In addition to the microbiological analysis the abiotic variables temperature, pH, dissolved oxygen, ammonia nitrogen, nitrite, nitrate, total nitrogen, orthophosphate, Chemical Oxygen Demand (COD) were evaluated. Analyses were performed in eight locations, one related to raw wastewater, one of treated effluent, three corresponding to the root zone interface and three to the sand filter, in a total of seven samples during a seasonal cycle. In 5 samples did not exhibit a reduction in the MPN of E. coli, only in Sample 1 (C1) and Sample 7 (C7) was observed approximately 66% and 97% reduction, respectively. Denitrifying bacteria in most spots and sulfate reducers, with the exception of the Sample 3 (C3) were determined in the amount of 1600 MPN.100mL-1. The density of nitrate-reducing bacteria ranged in most samples, from 1.8 MPN.100mL-1 to 19 MPN.100mL-1. The WTS was efficient for the removal of COD and phosphorus, the latter with removal percentage ranged from approximately 37% to 69 %. The concentration of ammonia-N was reduced in all samples, except for C3. The pH remained near neutrality and the concentration of dissolved oxygen increased in the region of the sand filter. Throughout the study period was observed a less growing of the plants. With the results of quantification it was possible verify that biodegradation is more intense in the first 50 cm of the WTS. It was observed significant reduction in the density of microorganisms in the sand filter compared with the root zone. Factors such as age of the station, which allowed the formation of a biofilm in the filter of gravel, the presence of sand filter and the availability of organic matter may be involved in the reduction of microorganisms. In summary it can be concluded that the WTS was efficient for removal of microorganisms, but only during periods of low rainfall.Os sistemas de tratamento de esgotos por zona de raízes constituem-se de um leito filtrante plantado com macrófitas emergentes. Tecnologia de baixo custo e, com eficiência comprovada em inúmeros trabalhos, as Estações de Tratamento de Efluentes (ETEs) por zona de raízes apresentam grande potencial para solucionar o problema da inexistência de coleta e tratamento de esgoto em pequenas comunidades. Este trabalho teve por objetivo caracterizar uma ETE por zona de raízes de fluxo vertical com base em variáveis abióticas e microbiológicas. Através da técnica de contagem em placas e da técnica de tubos múltiplos, foi possível estimar a densidade de fungos totais, bactérias heterotróficas, coliformes totais, Escherichia coli, bactérias redutoras de nitrato, bactérias desnitrificantes e bactérias redutoras de sulfato presentes nos diferentes estratos do sistema. Além das análises microbiológicas, foram avaliadas as variáveis abióticas temperatura, pH, oxigênio dissolvido (OD), nitrogênio amoniacal, nitrito, nitrato, nitrogênio total, ortofosfato e Demanda Química de Oxigênio (DQO). As análises foram realizadas em 8 locais, sendo uma referente ao efluente bruto, uma ao efluente tratado, três correspondendo à interface zona de raízes-brita e três ao filtro de areia, num total de 7 amostragens durante um ciclo sazonal. Em 5 amostragens não foi possível observar a redução do NMP de E. coli, apenas na Amostragem 1(C1) e na Amostragem 7 (C7) foi possível observar aproximadamente 66% e 97% de redução, respectivamente. As bactérias desnitrificantes, na maioria dos pontos e as redutoras de sulfato, com exceção da Amostragem 3 (C3), foram determinadas no valor de 1600 NMP.100mL-1. A densidade de bactérias redutoras de nitrato variou, na maioria das amostragens, de 1,8 NMP. 100mL-1 a 19 NMP. 100mL-1. A ETE foi eficiente para a remoção de DQO e fósforo, este último com porcentagem de remoção variando de, aproximadamente, 37% a 69%. A concentração de N-amoniacal foi reduzida em todas as amostragens, com exceção da C3. O pH permaneceu próximo da neutralidade e a concentração de oxigênio dissolvido aumentou na região do filtro de areia. Ao longo do período deste estudo foi observado um baixo desenvolvimento das plantas utilizadas. Com os resultados de quantificação foi possível verificar que a biodegradação é mais intensa nos primeiros 50 cm da ETE. Observou-se redução significativa da densidade de microrganismos no filtro de areia em relação à zona de raízes. Fatores como a idade da estação, que permitiu a formação de um biofilme no filtro de brita, a presença do filtro de areia e a disponibilidade de matéria orgânica podem estar envolvidas com a redução de microrganismos. Em resumo, pode se concluir que a ETE foi eficiente para remoção de microrganismos, porém apenas nos períodos de menor precipitação pluviométrica

Task-related edge density (TED) - a new method for revealing large-scale network formation in fMRI data of the human brain

The formation of transient networks in response to external stimuli or as a reflection of internal cognitive processes is a hallmark of human brain function. However, its identification in fMRI data of the human brain is notoriously difficult. Here we propose a new method of fMRI data analysis that tackles this problem by considering large-scale, task-related synchronisation networks. Networks consist of nodes and edges connecting them, where nodes correspond to voxels in fMRI data, and the weight of an edge is determined via task-related changes in dynamic synchronisation between their respective times series. Based on these definitions, we developed a new data analysis algorithm that identifies edges in a brain network that differentially respond in unison to a task onset and that occur in dense packs with similar characteristics. Hence, we call this approach "Task-related Edge Density" (TED). TED proved to be a very strong marker for dynamic network formation that easily lends itself to statistical analysis using large scale statistical inference. A major advantage of TED compared to other methods is that it does not depend on any specific hemodynamic response model, and it also does not require a presegmentation of the data for dimensionality reduction as it can handle large networks consisting of tens of thousands of voxels. We applied TED to fMRI data of a fingertapping task provided by the Human Connectome Project. TED revealed network-based involvement of a large number of brain areas that evaded detection using traditional GLM-based analysis. We show that our proposed method provides an entirely new window into the immense complexity of human brain function.Comment: 21 pages, 11 figure

Microstructural Parcellation of the Human Cerebral Cortex – From Brodmann's Post-Mortem Map to in vivo Mapping with High-Field Magnetic Resonance Imaging

The year 2009 marked the 100th anniversary of the publication of the famous brain map of Korbinian Brodmann. Although a “classic” guide to microanatomical parcellation of the cerebral cortex, it is – from today's state-of-the-art neuroimaging perspective – problematic to use Brodmann's map as a structural guide to functional units in the cortex. In this article we discuss some of the reasons, especially the problematic compatibility of the “post-mortem world” of microstructural brain maps with the “in vivo world” of neuroimaging. We conclude with some prospects for the future of in vivo structural brain mapping: a new approach which has the enormous potential to make direct correlations between microstructure and function in living human brains: “in vivo Brodmann mapping” with high-field magnetic resonance imaging

Pretraining is All You Need: A Multi-Atlas Enhanced Transformer Framework for Autism Spectrum Disorder Classification

Autism spectrum disorder (ASD) is a prevalent psychiatric condition characterized by atypical cognitive, emotional, and social patterns. Timely and accurate diagnosis is crucial for effective interventions and improved outcomes in individuals with ASD. In this study, we propose a novel Multi-Atlas Enhanced Transformer framework, METAFormer, ASD classification. Our framework utilizes resting-state functional magnetic resonance imaging data from the ABIDE I dataset, comprising 406 ASD and 476 typical control (TC) subjects. METAFormer employs a multi-atlas approach, where flattened connectivity matrices from the AAL, CC200, and DOS160 atlases serve as input to the transformer encoder. Notably, we demonstrate that self-supervised pretraining, involving the reconstruction of masked values from the input, significantly enhances classification performance without the need for additional or separate training data. Through stratified cross-validation, we evaluate the proposed framework and show that it surpasses state-of-the-art performance on the ABIDE I dataset, with an average accuracy of 83.7% and an AUC-score of 0.832. The code for our framework is available at https://github.com/Lugges991/METAForme

Connectivity Concordance Mapping: A New Tool for Model-Free Analysis of fMRI Data of the Human Brain

Functional magnetic resonance data acquired in a task-absent condition (“resting state”) require new data analysis techniques that do not depend on an activation model. Here, we propose a new analysis method called Connectivity Concordance Mapping (CCM). The main idea is to assign a label to each voxel based on the reproducibility of its whole-brain pattern of connectivity. Specifically, we compute the correlations of time courses of each voxel with every other voxel for each measurement. Voxels whose correlation pattern is consistent across measurements receive high values. The result of a CCM analysis is thus a voxel-wise map of concordance values. Regions of high inter-subject concordance can be assumed to be functionally consistent, and may thus be of specific interest for further analysis. Here we present two fMRI studies to demonstrate the possible applications of the algorithm. The first is a eyes-open/eyes-closed paradigm designed to highlight the potential of the method in a relatively simple domain. The second study is a longitudinal repeated measurement of a patient following stroke. Longitudinal clinical studies such as this may represent the most interesting domain of applications for this algorithm

Dynamic network participation of functional connectivity hubs assessed by resting-state fMRI

Network studies of large-scale brain connectivity have demonstrated that highly connected areas, or "hubs," are a key feature of human functional and structural brain organization. We use resting-state functional MRI data and connectivity clustering to identify multi-network hubs and show that while hubs can belong to multiple networks their degree of integration into these different networks varies dynamically over time. The extent of the network variation was related to the connectedness of the hub. In addition, we found that these network dynamics were inversely related to positive self-generated thoughts reported by individuals and were further decreased with older age. Moreover, the left caudate varied its degree of participation between a default mode subnetwork and a limbic network. This variation was predictive of individual differences in the reports of past-related thoughts. These results support an association between ongoing thought processes and network dynamics and offer a new approach to investigate the brain dynamics underlying mental experience

Donor Age of Human Platelet Lysate Affects Proliferation and Differentiation of Mesenchymal Stem Cells

The regenerative potential declines upon aging. This might be due to cell-intrinsic changes in stem and progenitor cells or to influences by the microenvironment. Mesenchymal stem cells (MSC) raise high hopes in regenerative medicine. They are usually culture expanded in media with fetal calf serum (FCS) or other serum supplements such as human platelet lysate (HPL). In this study, we have analyzed the impact of HPL-donor age on culture expansion. 31 single donor derived HPLs (25 to 57 years old) were simultaneously compared for culture of MSC. Proliferation of MSC did not reveal a clear association with platelet counts of HPL donors or growth factors concentrations (PDGF-AB, TGF-β1, bFGF, or IGF-1), but it was significantly higher with HPLs from younger donors (<35 years) as compared to older donors (>45 years). Furthermore, HPLs from older donors increased activity of senescence-associated beta-galactosidase (SA-βgal). HPL-donor age did not affect the fibroblastoid colony-forming unit (CFU-f) frequency, immunophenotype or induction of adipogenic differentiation, whereas osteogenic differentiation was significantly lower with HPLs from older donors. Concentrations of various growth factors (PDGF-AB, TGF-β1, bFGF, IGF-1) or hormones (estradiol, parathormone, leptin, 1,25 vitamin D3) were not associated with HPL-donor age or MSC growth. Taken together, our data support the notion that aging is associated with systemic feedback mechanisms acting on stem and progenitor cells, and this is also relevant for serum supplements in cell culture: HPLs derived from younger donors facilitate enhanced expansion and more pronounced osteogenic differentiation

Eigenvector Centrality Mapping for Analyzing Connectivity Patterns in fMRI Data of the Human Brain

Functional magnetic resonance data acquired in a task-absent condition (“resting state”) require new data analysis techniques that do not depend on an activation model. In this work, we introduce an alternative assumption- and parameter-free method based on a particular form of node centrality called eigenvector centrality. Eigenvector centrality attributes a value to each voxel in the brain such that a voxel receives a large value if it is strongly correlated with many other nodes that are themselves central within the network. Google's PageRank algorithm is a variant of eigenvector centrality. Thus far, other centrality measures - in particular “betweenness centrality” - have been applied to fMRI data using a pre-selected set of nodes consisting of several hundred elements. Eigenvector centrality is computationally much more efficient than betweenness centrality and does not require thresholding of similarity values so that it can be applied to thousands of voxels in a region of interest covering the entire cerebrum which would have been infeasible using betweenness centrality. Eigenvector centrality can be used on a variety of different similarity metrics. Here, we present applications based on linear correlations and on spectral coherences between fMRI times series. This latter approach allows us to draw conclusions of connectivity patterns in different spectral bands. We apply this method to fMRI data in task-absent conditions where subjects were in states of hunger or satiety. We show that eigenvector centrality is modulated by the state that the subjects were in. Our analyses demonstrate that eigenvector centrality is a computationally efficient tool for capturing intrinsic neural architecture on a voxel-wise level