Fine‐scale measurement of diffusivity in a microbial mat with nuclear magnetic resonance imaging

Noninvasive 1H‐nuclear magnetic resonance (NMR) imaging was used to investigate the diffusive properties of microbial mats in two dimensions. Pulsed field gradient NMR was used to acquire images of the H2O diffusion coefficient, Ds, and multiecho imaging NMR was used to obtain images of the water density in two structurally different microbial mats sampled from Solar Lake (Egypt). We found a pronounced lateral and vertical variability of both water density and water diffusion coefficient, correlated with the laminated and heterogeneous distribution of microbial cells and exopolymers within the mats. The average water density varied from 0.5 to 0.9, whereas the average water diffusion coefficient ranged from 0.4 to 0.9 relative to the values obtained in the stagnant water above the mat samples. The apparent water diffusivities estimated from NMR imaging compared well to apparent O2 diffusivities measured with a diffusivity microsensor. Analysis of measured O2 concentration profiles with a diffusion‐reaction model showed that both the magnitude of calculated rates and the depth distribution of calculated O2 consumption/production zones changed when the observed variations of diffusivity were taken into account. With NMR imaging, diffusivity can be determined at high spatial resolution, which can resolve inherent lateral and vertical heterogeneities found in most natural benthic systems

A nitrite microsensor for profiling environmental biofilms

A highly selective liquid membrane nitrite microsensor based on the hydrophobic ion-carrier aquocyano-cobalt(III) -hepta(2-phenylethyl)-cobrynate is described, The sensor has a tip diameter of 10 to 15 mu m. The response is log-linear in freshwater down to 1 mu M NO2- and in seawater to 10 mu M NO2-. A method is described for preparation of relatively large polyvinyl chloride (PVC)-gelled liquid membrane microsensors with a tip diameter of 5 to 15 mu m, having a hydrophilic coating on the tip, The coating and increased tip diameter resulted in more sturdy sensors, with a lower detection limit and a more stable signal than uncoated nitrite sensors with a tip diameter of 1 to 3 mu m. The coating protects the sensor membrane from detrimental direct contact with biomass and can be used for all PVC-gelled liquid membrane sensors meant for profiling microbial mats, biofilms, and sediments. Thanks to these improvements, liquid membrane sensors can now be used in complex environmental samples and in situ, e.g., in operating bioreactors. Examples of measurements in denitrifying, nitrifying, and nitrifying/denitrifying biofilms from wastewater treatment plants are shown. In all of these biofilms high nitrite concentrations were found in narrow zones of less than 1 mm

Saúde única, Terapia Comunitária Integrativa e covid-19: uma imersão fraternal em “um mundo, uma saúde”

In an attempt to verify the points of convergence between One Health, Integrative Community Therapy (ICT) and aspects of the COVID-19 Pandemic, a critical essay was proposed, through a qualitative approach that aimed to bring an interdisciplinary, interprofessional and intersectoral reading on the subject. To better understand the concepts and practical aspects of One Health and ICT, it was proposed the adaptation of One Health Umbrella’s figure, with elements of the ICT. The approach of One Health and ICT in face of globalization, the aspects of its complexity and the individual and collective empowerment to reach the administrative spheres, both in the elaboration of the planning and in the definition of the protocols that, as a rule, touch the citizen's skin. Therefore, One Health and ICT are articulated around a unique and fraternal vision of life.En un intento por verificar los puntos de convergencia entre Salud Única, Terapia Comunitaria Integradora (TCI) y los aspectos de la pandemia de COVID-19, se propuso un trabajo crítico de tipo ensayo, con un enfoque cualitativo que pretendió aportar una lectura interdisciplinaria, interprofesional e intersectorial sobre el tema. Para comprender mejor los conceptos y aspectos prácticos de la Salud Única y la TCI se propuso adaptar la figura de la “Sombrilla de Salud Única” con elementos de la TCI. El enfoque de la Salud Única y la TCI frente a la globalización, los aspectos de su complejidad y el empoderamiento individual y colectivo para llegar a las esferas administrativas, tanto en la elaboración de la planificación como en la definición de los protocolos que, por regla general, tocan la piel del ciudadano. Por lo tanto, la Salud Única y la TCI se articulan en torno a una visión única y fraternal de la vida.Na tentativa de verificar os pontos de convergência entre a Saúde Única, Terapia Comunitária Integrativa (TCI) e aspectos da Pandemia de COVID-19, foi proposto um trabalho do tipo ensaio crítico, com abordagem qualitativa que teve por finalidade trazer uma leitura interdisciplinar, interprofissional e intersetorial sobre o assunto. Para melhor compreensão dos conceitos e aspectos práticos da Saúde Única e TCI foi proposta a adaptação da figura do “Guarda-Chuva da Saúde Única” com elementos da TCI. A abordagem da Saúde Única e TCI frente a globalização, os aspectos de sua complexidade e o empoderamento individual e coletivo para alcançar as esferas administrativas, tanto na elaboração do planejamento quanto na definição dos protocolos que, via de regra, tocam a pele do cidadão. Portanto, a Saúde Única e a TCI se articulam em torno de uma visão única e fraterna da vida

Microscopic Cluster Model for Exotic Nuclei

For a better understanding of the dynamics of exotic nuclei it is of crucial importance to develop a practical microscopic theory easy to be applied to a wide range of masses. Theoretically the basic task consists in formulating an easy solvable theory able to reproduce structures and transitions of known nuclei which should be then used to calculate the sparely known properties of proton- or neutron-rich nuclei. In this paper we start by calculating energies and distributions of A\leq4 nuclei withing a unitary correlation model restricted to include only two-body correlations. The structure of complex nuclei is then calculated extending the model to include correlation effects of higher order.Comment: 10 pages, 4 figures. Final Version to be published in "Progress of Particle and Nuclear Physics (2007

Different carbon isotope fractionation patterns during the development of phototrophic freshwater and marine biofilms

Natural phototrophic biofilms are influenced by a broad array of abiotic and biotic factors and vary over temporal and spatial scales. Different developmental stages can be distinguished and growth rates will vary due to the thickening of the biofilm, which is expected to lead to a limitation of light or mass transport. This study shows that variation in CO<sub>2(aq)</sub> availability leads to a fractionation shift and thereby affects δ<sup>13</sup>C signatures during biofilm development. For phototrophic freshwater biofilms it was found that the δ<sup>13</sup>C value became less negative with the thickening of the biofilm, while the opposite trend was found in marine biofilms. Modeling and pH profiling indicated that the trend in the freshwater system was caused by an increase in CO<sub>2(aq)</sub> limitation resulting in an increase of HCO<sub>3</sub><sup>−</sup> as C-source. The opposite trend in the marine system could be explained by a higher heterotrophic biomass and activity causing a higher carbon recycling and thereby lower δ<sup>13</sup>C values. We conclude that δ<sup>13</sup>C was more related to the net areal photosynthesis rate and carbon recycling, rather than to the growth rate of the biofilms

Análises da viabilidade econômica da gaseificação de caroço de açaí no restaurante universitário da universidade federal rural da amazônia / Economic feasibility analysis of açaí core gasification at the university restaurant of the rural federal university of amazonia

O novo modelo desenvolvimentista alicerçado pela sustentabilidade, indica novos rumos para todas as nações do globo, desta forma o Brasil busca alternativas energéticas advindas de fontes renováveis de energia, devido à intensa exploração de fontes de energia advindas do petróleo. Neste sentido, este trabalho propõe a implantação de um sistema de gaseificação de biomassa (caroço de açaí) para suprir a demanda energética do restaurante universitário da Universidade Federal Rural da Amazônia (UFRA). A gaseificação evidencia-se como alternativa viável social e economicamente. No que tange a análise de viabilidade econômica em torno do sistema proposto verificou-se que o projeto possuí um VPL de R$174.768,79, uma taxa interna de retorno (TIR) de 12,39$/kWh, resultando em um payback de 24,78 anos. Tais análises consideram o projeto viável economicamente, principalmente, devido à quantidade de biomassa disponível no bairro da Universidade