Eigenstate versus Zeeman-based approaches to the solid-effect

The solid effect is one of the simplest and most effective mechanisms for Dynamic Nuclear Polarization. It involves the exchange of polarization between one electron and one nuclear spin coupled via the hyperfine interaction. Even for such a small spin system, the theoretical understanding is complicated by the contact with the lattice and the microwave irradiation. Both being weak, they can be treated within perturbation theory. In this work, we analyze the two most popular perturbation schemes: the Zeeman and the eigenstate-based approaches which differ in the way the hyperfine interaction is treated. For both schemes, we derive from first principles an effective Liouville equation which describes the density matrix of the spin system; we then study numerically the behavior of the nuclear polarization for several values of the hyperfine coupling. In general, we obtain that the Zeeman-based approach underestimates the value of the nuclear polarization. By performing a projection onto the diagonal part of the spin-system density matrix, we are able to understand the origin of the discrepancy, which is due to the presence of parasite leakage transitions appearing whenever the Zeeman basis is employed.Comment: 9 pages, 4 figures, 7 pages of supplementary materia

A Note on the Estimation of the Hölder Constant

In this article, we develop a nonparametric estimator for the Hölder constant of a density function. We consider a simulation study to evaluate the performance of the proposal and construct smooth bootstrap confidence intervals. Also, we give a brief review over the impossibility to decide whether a density function is Hölder.Fil: Henry, Guillermo Sebastian. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rodriguez, Daniela Andrea. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sued, Raquel Mariela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Three-Year-Old Agents of Social Change: How aeioTU Educators Build on Children’s Agency

aeioTU is a Colombian organization that works to enact social change through the field of early childhood education. In collaboration with the Colombian government, aeioTU oversees several public centers located in socioeconomically vulnerable municipalities in Colombia. This thesis analyzes the aeioTU curriculum and the practices of several aeioTU teachers through the theoretical lens of Freire’s critical pedagogy. This thesis argues that by fostering critical awareness of the world from an early age, as well as by collaborating closely with mothers and the communities at large, aeioTU teachers equip children with the tools to become social agents who can challenge and positively change their lived realities. The research presented in this thesis affirms the potential of aeioTU teachers to enact social change in socioeconomically vulnerable communities by building on young children’s social agency

Estudo experimental do comportamento ocular em trabalhadores administrativos como um indicador de conforto visual em situação de risco de encadeamento

The daylight impact on the visual environment is fundamental on visual display terminal work (VDT). Visual performance and visual comfort should be considered for equal. The study (n=16) was performed at the experimental lighting laboratory. Office work with VDT was evaluated using STROOP task in two orientations: (with/without solar presence in the visual field). Our hypothesis states the existence of a relationship between ocular behavior and visual comfort of workers. An eye-tracker was employed in order to record the ocular gestural parameters: blinks, direction of gaze, eye aperture (Degree of eye?s openness) and pupil size, which were correlated with the vertical illuminance at the eye. Visual comfort was assessed with Glare Sensation Vote. Results indicate a strong negative linear correlation between eye illuminance and the degree of eye?s openness in the direct sunlight scenario (p=-0.636; s=0.008) and in diffuse light scenario (p=-0.661; s=0.005), that could be the main predictor of visual discomfort. This experiment allowed us to explore eye behavior patterns that could be visual comfort indices under glare risk situations.O impacto a luz do dia no ambiente visual é fundamental para o trabalho no Ecrã de Visualização de Dados (EDV). Desempenho visual e conforto visual devem ser considerados em igual. O estudo (n = 16) foi realizado no laboratório experimental de iluminação. O trabalho de escritório com EDV foi avaliado utilizando a tarefa de Stroop em duas orientações: (com / sem presença solar no campo visual). A nossa hipótese afirma a existência de uma relação entre o comportamento ocular e conforto visual dos trabalhadores. Um “eye-tracker” foi desenvolvido para gravar os parâmetros gestuais oculares: pestanejar, direção do olhar, abertura dos olhos (Grau de abertura do olho) e tamanho da pupila, que foram correlacionados com a iluminância vertical no olho. Conforto visual foi avaliado com a escala de sensação de encadeamento. Os resultados indicam uma correlação linear negativa forte entre a luminosidade dos olhos e do grau de abertura de olho no cenário de luz solar direta (p = -0,636; s = 0,008) e no cenário de luz difusa (p = -0,661; s = 0,005), que poderia ser o principal preditor de desconforto visual. Esta experiência permitiu-nos explorar padrões de comportamento do olho que poderiam ser os índices de conforto visual em situação de risco de encadeamento.Fil: Yamin Garretón, Julieta Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; ArgentinaFil: Rodriguez, Roberto Germán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; ArgentinaFil: Pattini, Andrea Elvira. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentin

Genetic mapping of metabolic biomarkers of cardiometabolic diseases

Cardiometabolic disorders (CMDs) are a major public health problem worldwide. The main goal of this thesis is to characterize the genetic architecture of CMD-related metabolites in a Lebanese cohort. In order to maximise the extraction of meaningful biological information from this dataset, an important part of this thesis focuses on the evaluation and subsequent improvement of the standard methods currently used for molecular epidemiology studies. First, I describe MetaboSignal, a novel network-based approach to explore the genetic regulation of the metabolome. Second, I comprehensively compare the recovery of metabolic information in the different 1H NMR strategies routinely used for metabolic profiling of plasma (standard 1D, spin-echo and JRES). Third, I describe a new method for dimensionality reduction of 1H NMR datasets prior to statistical modelling. Finally, I use all this methodological knowledge to search for molecular biomarkers of CMDs in a Lebanese population. Metabolome-wide association analyses identified a number of metabolites associated with CMDs, as well as several associations involving N-glycan units from acute-phase glycoproteins. Genetic mapping of these metabolites validated previously reported gene-metabolite associations, and revealed two novel loci associated with CMD-related metabolites. Collectively, this work contributes to the ongoing efforts to characterize the molecular mechanisms underlying complex human diseases.Open Acces

Development of free sugar white chocolate, suitable for diabetics, using Stevia and sucralose as sweeteners: study of the thermal degradation kinetic

The purpose of this study was the development of formulations of white chocolate for diabetics with replacement of sucrose by sucralose (Su) and Stevia (St) using a mixture experimental design. The kinetic studies of thermodegradation which showed that binary combinations of Stevia with sucrose had synergistic effects since the matrix presented a lower thermal sensitivity to the non-enzymatic browning reaction than the samples formulated from the individual components. The phenomena of blooming during storage were studied by a computer vision system and image analysis. The results of sensory analysis revealed that the sample 100%St was not acceptable; however, combining Stevia with sucrose and sucralose, acceptable sensory chocolates were obtained with no statistically significant differences, compared to control 100%S (P> 0.05). Our study provides a chocolate suitable for diabetics, with an appropriate combination of sensorially acceptable sweeteners with higher stability than control sample.Fil: Rodriguez Furlan, Laura Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Invest. En Tecnología Química; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; ArgentinaFil: Baracco, Yanina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; ArgentinaFil: Zaritzky, Noemi. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Campderrós, Mercedes. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentin