The root systems of permian arborescent sphenopsids: evidence from the northern and southern hemispheres

Anatomically preserved calamitalean trunks are described from the Permian fossil forests of Chemnitz, Germany, and Tocantins, central-north Brazil. Several trunk bases were found in situ, still rooting in their former substrate or in parautochthonous sediments and revealing multiple organic connections between stems and roots. The new evidence of several free-stemmed Permian calamitaleans from different fossil lagerstatten and different taphonomic modes from the Northern and Southern hemispheres has implications for understanding calamite growth and challenges the universal validity of the reconstruction of rhizome-bearing woody trees. Whereas the stems belong to different species of the widely distributed genus Arthropitys GOEPPERT 1864, among them the generitype A. bistriata (COTTA) emend. RoSSLER, FENG & NOLL 2012 the attached roots represent the largest calamite roots ever found and incorporate a broad spectrum of preservational forms and ontogenetic stages. The latter are represented by the root genera Astromyelon WILLIAMSON 1878, Myriophylloides HICK & CASH 1881 and Asthenomyelon LEISTIKOW 1962 that were evidenced for the first time from Chemnitz, the type locality of Arthropitys and Calamitea (COTTA) emend. ROSSLER & NOLL 2007. Branched, stem-borne, adventitious root systems exhibit similar architectures, arise from different nodes of the lowermost trunks and anchor the trees in' different substrates. Developmental features were analysed in first- to third-order roots, which possess clearly-defined concentric tissue zones: epidermis/periderm, cortex, endodermis and central vascular tissue with or without pith. First-order roots, in particular, show considerable secondary growth. Numerous zones of concentric density variation in the secondary xylem indicate some kind of seasonality in the early Permian environments.

An alternative approach for quasi-truth

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

análise dos efeitos ionosféricos de ordem superior no ciclo solar 24 e influência no posicionamento GNSS absoluto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Uma investigação do minos e sua aplicação ao problema de fluxo de potência ótimo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo de órbitas periódicas em equações diferenciais não autônomas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Preparation and characterization of PEG-coated silica nanoparticles for oral insulin delivery

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Combined photoelectrocatalytic/electro-Fenton process using a Pt/TiO2NTs photoanode for enhanced degradation of an azo dye: A mechanistic study

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Adsorption of pH-responsive polyelectrolyte chains onto spherical macroions

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desenvolvimento, otimização e caracterização física de um novo sistema multi-sensores de Biosusceptometria de Corrente Alternada (BAC) para obtenção de imagens biomagnéticas

A novel AC Biosusceptometry (ACB) system with thirteen sensors it was implemented and characterized in vitro using magnetic phantoms. The system presenting coils in a coaxial arrangement with one pair of excitation coil outside and thirteen pairs of detection coils inside. A first-order gradiometric configuration was utilized for optimal detection of magnetic signals. Several physical parameters such as baseline, number of turns, excitation field and diameters were studied for improvement of the signal/noise ratio. This system exhibits an enhanced sensitivity and spatial resolution, due to the higher density of sensors/area. In the future those characteristics will turn possible to obtain images of magnetic marker or tracer in the gastrointestinal tract focusing on physiological and pharmaceutical studies. ACB emerged due to its interesting nature, noninvasiveness and low cost to investigate gastrointestinal parameters and this system can contribute for more accurate interpretation of biomedical signals and images

Tomografia por Biosusceptometria de Corrente Alternada (tBAC): desenvolvimento, caracterização, implementação

The Biosusceptometry AC (BAC) is a research tool that has been extensively explored by the group Biomagnetism IBB-UNESP for monitoring of the gastrointestinal tract, its response to a known drug or in vivo performance of solid dosage forms. During this period the BAC, which has the characteristics of high sensitivity and low cost, has been developed primarily for recording signals contraction of activity and traffic human gastrointestinal tract. With the possibility of producing images with this instrumentation, it was possible to evaluate different situations in vitro and in vivo for physiological studies and pharmaceuticals. Considering the good performance of this system to produce planar images, the first aim of the BAC system tomography (TBAC) was to evaluate the system performance of BAC to produce tomographic images of phantoms ferromagnetic for a single channel system. All these applications were only possible because of their sensitivity to materials of high magnetic suscepitibility as ferrite, which allow to produce an electrical signal proportional to the variation of the magnetic flux generated by the presence of magnetic marker next to a first-order gradiometer. Measuring this variation at various points was possible to generate planar images that recently came to be produced in systems with multiple detectors, said multi-channels. From planar images, also producing tomographic images of simulators BAC bars in a system of 13 channels using only the center channel, with good results when applied to simple objects as one and two bars. When testing the resolution of the system with more elaborate forms the quality and resolution of images reconstructed is not satisfactory, which would be solved by increasing the spatial sampling rate and hence the acquisition time. The present system works with an acquisition time of about five hours. Whereas this system will be applied for in vivo experiments, the acquisition time became a ...

Cinética de hidrólise de GPTS sob estimulação ultrassônica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação do efeito da gastrectomia na motilidade e no esvaziamento gástrico em ratos por biosusceptometria de corrente alternada

The study of gastrointestinal tract (GIT) functions is necessary due to the increasing number of pathologies associated with it. Directly influencing the quality of life, the gastrointestinal tract provides a number of parameters that, when analyzed, allow us to describe its dysfunctions. Thus, many techniques can be combined to obtain these properties related to the GIT. However, these techniques are often invasive, require surgery, catheter insertion, or to build a temporal model of these functions, require the sacrifice of animals in a series of data collection. The technique used in this study has the advantage of having a low operating cost, being free of ionizing radiation, non-invasive and is known as biosusceptometry AC (BAC), used to evaluate the properties of the GI tract by monitoring the position and concentration of materials magnetically marked. The sensor consists of two pairs of coils, one reference and one for detection. A fixed base line separates the sensing and reference coils, and also functions as support for the instrumentation. It is also important to note that the detection coils are arranged in a first order (subtraction) gradiometric way. The objective of this study was to analyze the effects of gastrectomy in gastric emptying and gastrointestinal transit time of solid food in rats using a BAC system associated with magnetic markers. To realize this study was constructed a dedicated BAC sensor, built to analyze these GIT properties. Data acquisition was obtained by aligning the magnetic sensor with the stomach and colon of the animal at pre-determined intervals. Thus, when approaching the magnetic material of the sensor, the balance created between the two sides of the sensor is broken. This imbalance can be measured, digitized and acquired. Tracer was used as a ration magnetically marked with ferrite... (Complete abstract click electronic access below)

Estudo comparativo de modelos matemáticos de qualidade de águas superficiais

Surface water quality models have been developed since 1925, when Streeter e Phelps created first order equations that represent the balance between DO and BOD. Since then, and specially after the ‘60s, new computational technologies evolved, making it possible to create more complex models, which try to represent, through mathematics, natural phenomena like eutrophication and rivers self-depuration. As main objective of such models is the understanding of aquatic systems and the relationship between them and the environment, so that it can support decision makers in creating water manage plans and in elaborating environmental projects of such resources. Regarding to that, it is of crucial importance the understanding of the models structures, so that one can choose the most appropriate model for the river in question. While one-dimensional models like QUAL2K are more appropriate for long and narrow rivers, bi- or tridimensional models (CE-QUAL-W2, WASP and CEQUAL- ICM) are more commonly used in wide and slower rivers, with higher lateral and/or vertical mixes rates. Besides, the more complex is the river studied more complex the model should be, which demands more costs and time for the model to be applied