Consumo consciente de água: a criança como agente de transformação

Educar é desafio diário, tanto para os pais quanto para os professores. Uma função que deve ser desempenhada com atenção, cuidado e, acima de tudo, dedicação. A troca de experiências entre o mestre e o aluno pode gerar um ciclo saudável de influência e aprendizado. Sob esta plataforma, a perpetuação do pensamento crítico acontecerá de forma natural, despertando e fixando o conceito de cidadania, o qual será aplicado na sociedade e nos demais relacionamentos que o homem consolidar. O respeito ao meio ambiente, por exemplo, é uma alternativa efetiva para a propagação da empatia e coletividade. Em especial, o consumo consciente da água, a fonte da vida, e matéria prima indispensável para os três setores da economia. Assunto este que deveria estar presentes no cotidiano do brasileiro. Na busca por compreender tal problema e desenvolver novos valores para a sociedade moderna, a comunicação e o marketing são as ferramentas oportunas para alavancar o processo de conscientização da criança. Se o processo ocorrer de forma concreta, em um futuro próximo, os impactos ambientais do homem sob a natureza serão amenizados e a qualidade de vida uma realidade coletiva. Neste estudo, o qual usou pesquisa qualitativa e grupo focal, a coleta de dados possibilitou a reflexão acerca de métodos adequados para conscientizar o cidadão quanto à importância do uso consciente da água desde a infância. A partir da pequena amostra escolhida, foi observada a realidade da capital federal, o valor e custo beneficio em relação a natureza e que atitudes pró natureza, principalmente por parte de instituições privadas e não governamentais, já estão sendo executadas

Iron and Neurodegeneration in Multiple Sclerosis

Increased iron deposition might be implicated in multiple sclerosis (MS). Recent development of MRI enabled to determine brain iron levels in a quantitative manner, which has put more interest on studying the role of iron in MS. Evidence for abnormal iron homeostasis in MS comes also from analyses of iron and iron-related proteins in CSF and blood and postmortem MS brain sections. However, it is not yet clear if iron accumulation is implicated in MS pathology or merely reflects an epiphenomenon. Further interest has been generated by the idea of chronic cerebrospinal venous insufficiency that might be associated with brain iron accumulation due to a reduction in venous outflow, but its existence and etiologic role in MS are currently controversially debated. In future studies, combined approaches applying quantitative MRI together with CSF and serum analyses of iron and iron-related proteins in a clinical followup setting might help to elucidate the implication of iron accumulation in MS

Hybrid data fidelity term approach for quantitative susceptibility mapping

PURPOSE: Susceptibility maps are usually derived from local magnetic field estimations by minimizing a functional composed of a data consistency term and a regularization term. The data-consistency term measures the difference between the desired solution and the measured data using typically the L2-norm. It has been proposed to replace this L2-norm with the L1-norm, due to its robustness to outliers and reduction of streaking artifacts arising from highly noisy or strongly perturbed regions. However, in regions with high SNR, the L1-norm yields a suboptimal denoising performance. In this work, we present a hybrid data fidelity approach that uses the L1-norm and subsequently the L2-norm to exploit the strengths of both norms. METHODS: We developed a hybrid data fidelity term approach for QSM (HD-QSM) based on linear susceptibility inversion methods, with total variation regularization. Each functional is solved with ADMM. The HD-QSM approach is a two-stage method that first finds a fast solution of the L1-norm functional and then uses this solution to initialize the L2-norm functional. In both norms we included spatially variable weights that improve the quality of the reconstructions. RESULTS: The HD-QSM approach produced good quantitative reconstructions in terms of structural definition, noise reduction, and avoiding streaking artifacts comparable with nonlinear methods, but with higher computational efficiency. Reconstructions performed with this method achieved first place at the lowest RMS error category in stage 1 of the 2019 QSM Reconstruction Challenge. CONCLUSIONS: The proposed method allows robust and accurate QSM reconstructions, obtaining superior performance to state-of-the-art methods

Eklektik - Verantwortung - Glück

Adorno – so die These der vorliegenden Arbeit – war – gleich den meisten Philosophen – ein Eklektiker. Er hat sich bewusst beeinflussen und anregen lassen von anderen Denkern, Dichtern und Künstlern, wählte aus deren Werk so manches, das er in sein Werk und seine Schriften aufnahm, um daraus etwas Eigenes, Neues zu schaffen und zu gestalten. Adornos Herangehensweise entwuchs seiner zwar systematischen, aber offenen Philosophie, die sich eben nicht als geschlossenes System begriff, sondern vielmehr als eine in Essays dargestellte dialektisch verwobene Konstellation von Begriffen, vergleichbar einem verlinkten Hypertext oder einer Enzyklopädie: die Begriffe beziehen sich aufeinander, bedingen einander und verweisen darüber hinaus oftmals noch auf ein Drittes, worin auch die methodische Vorgabe für vorliegende Arbeit zu sehen ist. Tritt etwas Neues hinzu oder eine Veränderung innerhalb der Konstellation ein, so verändert und verschiebt sich das Gesamtbild gleich dem Gewebe eines Teppichs oder dem Gefüge eines Mosaiks: die Gesamtheit der Elemente ist deutlich mehr und etwas anderes als die Summe der Teile. Viele dieser Elemente sind nun, in eklektischer Manier, entliehen aus dem Werk anderer. Dies zu zeigen und darzustellen, wurde in vorliegender Arbeit das Begriffspaar „Entscheidung – Verantwortung“ herangezogen. Das Moment der Entscheidung liegt zunächst in der Auswahl derer, über die Adorno schrieb, auf die er sich bezog und anhand derer er seine eigenen Gedanken entwickelte und seine Philosophie zur Darstellung brachte; im Weiteren in einem bestimmten Verhältnis gegenüber der Praxis, wie er sie verstand und die einen solchen Namen verdiente. Je eigene reflektierte Entscheidungen und die daraus entwachsenen Erfahrungen führen – so wäre mit Adorno zu hoffen – in Folge zu einem Denken, das sich der eigenen Verantwortung bewusst ist; einem Denken, das um die eigene Bedingtheit, Naturhaftigkeit und Eingeschränktheit weiß, das den Widersprüchen der Gesellschaft, in die es verflochten ist, sich stellt und dem es um eine echte Versöhnung geht. Einer Versöhnung, die das Glück des je Einzelnen insofern zum Ziel hat, als das wahre Glück des Einzelnen immer auf jenes einer geglückten, versöhnten Gesellschaft verweist, in der jegliche dialektische Spannung gehalten wird: das je Andere muss nicht dem eigenen Denken angeglichen und solcherart zurecht gebogen werden, vielmehr soll ihm Gerechtigkeit widerfahren. Das Tauschverhältnis, dem Adorno nachspürte, und das er als Grundstruktur rationalistischen Denkens erkannte, wird solcherart durchbrochen. Das Ich – nach Adorno – bildet sich nicht dort, wo es sich setzt, sondern erst dort, wo es den Anfordernissen des Denkens standhält und zurücktritt vom Beharren auf den eigenen Standpunkt, wo es sich verschenkt und wo es Gnade vor Recht ergehen lässt, das Gleich um Gleich durchbricht, ohne entsagen zu müssen.Adorno, like most philosophers, was an eclectic. This fact forms the theory of this thesis. He purposely let himself be influenced by other thinkers, poets and artists. He chose parts of their works which he absorbed into his own, to create something new and individual. Adorno’s approach grew out of his systematic but open philosophy. His philosophy was not an enclosed system but a dialectic and interweaved constellation of terms illustrated in essays. It can be compared to a linked hypertext or an encyclopedia: the terms reference each other, determine each other and beyond this often refer to something else. This is the origin of the methodological basis of this thesis. The whole picture changes or shifts like the weave of a carpet or an arrangement of a mosaic if something new appears or if a change within the constellation occurs: the entity of the elements is considerably more than the total of all parts. Many of these elements are, in an eclectic way, borrowed from someone else’s work. In the following thesis the pair of terms “decision” and “responsibility” are used to show this. The first decision is made in the selection of those who Adorno wrote about, those he referred to and those through whom he developed his own thoughts and philosophy. Furthermore, his philosophy is founded in the relation to practice, as he understood the term practice, and which deserved this term. According to Adorno, self reflected decisions and the experiences resulting from them, hopefully lead to a way of thinking in conscious responsibility. They lead to a way of thinking that is aware of its own conditionality, natural manner and limitation. This way of thinking faces antagonism in the society in which it is embedded. It longs for reconciliation in the hope of finding happiness for everyone, as true happiness is always indicative of a reconcile society. In such a society every dialectic strain is kept: what is different does not have to be adjusted and formed. In fact, justice prevails. The concept of thinking in terms of exchange values which Adorno exposed as a basis for rational thinking has to be shattered. The ego, according to Adorno, is not formed where it settles but where it resists the challenges of thinking, where it steps back to its own position, where it gives itself away, where it allows mercy instead of legal doctrine and where it breaks the concept of an eye for an eye without renouncement

Accelerated mapping of magnetic susceptibility using 3D planes-on-a-paddlewheel (POP) EPI at ultra-high field strength

With the advent of ultra-high field MRI scanners in clinical research, susceptibility based MRI has recently gained increasing interest because of its potential to assess subtle tissue changes underlying neurological pathologies/disorders. Conventional, but rather slow, three-dimensional (3D) spoiled gradient-echo (GRE) sequences are typically employed to assess the susceptibility of tissue. 3D echo-planar imaging (EPI) represents a fast alternative but generally comes with echo-time restrictions, geometrical distortions and signal dropouts that can become severe at ultra-high fields. In this work we assess quantitative susceptibility mapping (QSM) at 7T using non-Cartesian 3D EPI with a planes-on-a-paddlewheel (POP) trajectory, which is created by rotating a standard EPI readout train around its own phase encoding axis. We show that the threefold accelerated non-Cartesian 3D POP EPI sequence enables very fast, whole brain susceptibility mapping at an isotropic resolution of 1mm and that the high image quality has sufficient signal-to-noise ratio in the phase data for reliable QSM processing. The susceptibility maps obtained were comparable with regard to QSM values and geometric distortions to those calculated from a conventional 4min 3D GRE scan using the same QSM processing pipeline

Fast quantitative susceptibility mapping with L1-regularization and automatic parameter selection

Purpose To enable fast reconstruction of quantitative susceptibility maps with total variation penalty and automatic regularization parameter selection. Methods ℓ[subscript 1]-Regularized susceptibility mapping is accelerated by variable splitting, which allows closed-form evaluation of each iteration of the algorithm by soft thresholding and fast Fourier transforms. This fast algorithm also renders automatic regularization parameter estimation practical. A weighting mask derived from the magnitude signal can be incorporated to allow edge-aware regularization. Results Compared with the nonlinear conjugate gradient (CG) solver, the proposed method is 20 times faster. A complete pipeline including Laplacian phase unwrapping, background phase removal with SHARP filtering, and ℓ[subscript 1]-regularized dipole inversion at 0.6 mm isotropic resolution is completed in 1.2 min using MATLAB on a standard workstation compared with 22 min using the CG solver. This fast reconstruction allows estimation of regularization parameters with the L-curve method in 13 min, which would have taken 4 h with the CG algorithm. The proposed method also permits magnitude-weighted regularization, which prevents smoothing across edges identified on the magnitude signal. This more complicated optimization problem is solved 5 times faster than the nonlinear CG approach. Utility of the proposed method is also demonstrated in functional blood oxygen level–dependent susceptibility mapping, where processing of the massive time series dataset would otherwise be prohibitive with the CG solver. Conclusion Online reconstruction of regularized susceptibility maps may become feasible with the proposed dipole inversion

Streaking artifact suppression of quantitative susceptibility mapping reconstructions via L1-norm data fidelity optimization (L1-QSM)

Purpose: The presence of dipole-inconsistent data due to substantial noise or artifacts causes streaking artifacts in quantitative susceptibility mapping (QSM) reconstructions. Often used Bayesian approaches rely on regularizers, which in turn yield reduced sharpness. To overcome this problem, we present a novel L1-norm data fidelity approach that is robust with respect to outliers, and therefore prevents streaking artifacts. Methods: QSM functionals are solved with linear and nonlinear L1-norm data fidelity terms using functional augmentation, and are compared with equivalent L2-norm methods. Algorithms were tested on synthetic data, with phase inconsistencies added to mimic lesions, QSM Challenge 2.0 data, and in vivo brain images with hemorrhages. Results: The nonlinear L1-norm-based approach achieved the best overall error metric scores and better streaking artifact suppression. Notably, L1-norm methods could reconstruct QSM images without using a brain mask, with similar regularization weights for different data fidelity weighting or masking setups. Conclusion: The proposed L1-approach provides a robust method to prevent streaking artifacts generated by dipole-inconsistent data, renders brain mask calculation unessential, and opens novel challenging clinical applications such asassessing brain hemorrhages and cortical layers

Susceptibility induced gray–white matter MRI contrast in the human brain

AbstractMR phase images have shown significantly improved contrast between cortical gray and white matter regions compared to magnitude images obtained with gradient echo sequences. A variety of underlying biophysical mechanisms (including iron, blood, myelin content, macromolecular chemical exchange, and fiber orientation) have been suggested to account for this observation but assessing the individual contribution of these factors is limited in vivo.For a closer investigation of iron and myelin induced susceptibility changes, postmortem MRI of six human corpses (age range at death: 56–80years) was acquired in situ. Following autopsy, the iron concentrations in the frontal and occipital cortex as well as in white matter regions were chemically determined. The magnetization transfer ratio (MTR) was used as an indirect measure for myelin content. Susceptibility effects were assessed separately by determining R2* relaxation rates and quantitative phase shifts. Contributions of myelin and iron to local variations of the susceptibility were assessed by univariate and multivariate linear regression analysis.Mean iron concentration was lower in the frontal cortex than in frontal white matter (26±6 vs. 45±6mg/kg wet tissue) while an inverse relation was found in the occipital lobe (cortical gray matter: 41±10 vs. white matter: 34±10mg/kg wet tissue). Multiple regression analysis revealed iron and MTR as independent predictors of the effective transverse relaxation rate R2* but solely MTR was identified as source of MR phase contrast. R2* was correlated with iron concentrations in cortical gray matter only (r=0.42, p<0.05).In conclusion, MR phase contrast between cortical gray and white matter can be mainly attributed to variations in myelin content, but not to iron concentration. Both, myelin and iron impact the effective transverse relaxation rate R2* significantly. Magnitude contrast is limited because it only reflects the extent but not the direction of the susceptibility shift

Time-optimized high-resolution readout-segmented diffusion tensor imaging

Readout-segmented echo planar imaging with 2D navigator-based reacquisition is an uprising technique enabling the sampling of high-resolution diffusion images with reduced susceptibility artifacts. However, low signal from the small voxels and long scan times hamper the clinical applicability. Therefore, we introduce a regularization algorithm based on total variation that is applied directly on the entire diffusion tensor. The spatially varying regularization parameter is determined automatically dependent on spatial variations in signal-to-noise ratio thus, avoiding over- or under-regularization. Information about the noise distribution in the diffusion tensor is extracted from the diffusion weighted images by means of complex independent component analysis. Moreover, the combination of those features enables processing of the diffusion data absolutely user independent. Tractography from in vivo data and from a software phantom demonstrate the advantage of the spatially varying regularization compared to un-regularized data with respect to parameters relevant for fiber-tracking such as Mean Fiber Length, Track Count, Volume and Voxel Count. Specifically, for in vivo data findings suggest that tractography results from the regularized diffusion tensor based on one measurement (16 min) generates results comparable to the un-regularized data with three averages (48 min). This significant reduction in scan time renders high resolution (1×1×2.5 mm3) diffusion tensor imaging of the entire brain applicable in a clinical context

Quantitative susceptibility mapping (QSM) as a means to measure brain iron? A post mortem validation study

AbstractQuantitative susceptibility mapping (QSM) is a novel technique which allows determining the bulk magnetic susceptibility distribution of tissue in vivo from gradient echo magnetic resonance phase images. It is commonly assumed that paramagnetic iron is the predominant source of susceptibility variations in gray matter as many studies have reported a reasonable correlation of magnetic susceptibility with brain iron concentrations in vivo. Instead of performing direct comparisons, however, all these studies used the putative iron concentrations reported in the hallmark study by Hallgren and Sourander (1958) for their analysis. Consequently, the extent to which QSM can serve to reliably assess brain iron levels is not yet fully clear. To provide such information we investigated the relation between bulk tissue magnetic susceptibility and brain iron concentration in unfixed (in situ) post mortem brains of 13 subjects using MRI and inductively coupled plasma mass spectrometry. A strong linear correlation between chemically determined iron concentration and bulk magnetic susceptibility was found in gray matter structures (r=0.84, p<0.001), whereas the correlation coefficient was much lower in white matter (r=0.27, p<0.001). The slope of the overall linear correlation was consistent with theoretical considerations of the magnetism of ferritin supporting that most of the iron in the brain is bound to ferritin proteins. In conclusion, iron is the dominant source of magnetic susceptibility in deep gray matter and can be assessed with QSM. In white matter regions the estimation of iron concentrations by QSM is less accurate and more complex because the counteracting contribution from diamagnetic myelinated neuronal fibers confounds the interpretation