Conjugations on the Hardy space H2H^{2}

A conjugation $C$ on a separable complex Hilbert space $\mathcal H$ is an antilinear operator that is isometric and involutive. In this notes, we characterize all conjugations on the Hardy-Hilbert space $H^{2}$ over the disk. In addition, we characterize complex symmetric Toeplitz operators with a special type of these conjugations.Comment:

Estudio de la radiación neta en zonas semiáridas utilizando modelos lineales y neuronales y la sinergia entre GERB y SEVIRI

Las regiones áridas o semiáridas se caracterizan por una distribución irregular de los recursos hídricos, lo que muchas veces constituye una limitación para el desarrollo de una determinada región. La variabilidad hidrológica de estas regiones se debe a la mala distribución espacial y temporal de la lluvia, a la topografía heterogénea y a los cambios de origen antropogénicos que muchas veces conducen a procesos de degradación y de desertificación. Como en estas regiones la evapotranspiración explica una parte significativa de la pérdida de agua hacia la atmósfera, el estudio y modelización de la radiación neta en superficie (Rn), es de suma importancia, una vez que las estimaciones o mediciones de Rn se utilizan, por ejemplo, para el cálculo de la evapotranspiración que, a su vez, se usa para optimizar la calidad y el rendimiento de los cultivos, la planificación de los recursos hídricos y previsiones climáticas. Por tanto, este proyecto tiene como objetivo principal el estudio de la radiación neta en regiones semiáridas utilizando modelos lineales y neuronales y la sinergia entre los sensores GERB (Geostationary Earth Radiation Budget) y SEVIRI (Spinning Enhanced Visible and InfraRed Imager). Como R_n es una medida de la energía radiativa disponible en la superficie y es la fuerza motriz en muchos procesos físicos y biofísicos requeridos por los sistemas suelo-vegetación-atmósfera, para alcanzar los objetivos propuestos y descritos a seguir, su estudio se realiza sobre diferentes superficies: suelo desnudo, matorral y viñas y en diferentes condiciones considerando días con cielo despejado, días nubosos y días con nubosidad variable. También se ha modelizado Rn y se ha estimado el flujo de calor en suelo (G) a partir de observaciones de Rn. Los diagramas de dispersión entre las variables Rn y G indicaron que la relación entre ambas variables presentaba una tendencia lineal creciente, lo que llevó a aplicar un modelo de regresión lineal simple para obtener G a partir de Rn. Los modelos obtenidos presentan un alto coeficiente de correlación (R2 = 0,78 y 0,89) y, en promedio, el componente G, obtenido partir de los modelos lineales, representaba aproximadamente un 18% de Rn. Durante el desarrollo del trabajo se identificó que los modelos neuronales son herramientas muy útiles para estimar Rn en superficie a partir de parámetros meteorológicos, principalmente en zonas donde los flujos relacionados con la radiación no se miden de manera rutinaria. Los análisis del modelo neuronal propuesto han demostrado que es posible estimar Rn a partir de datos meteorológicos medidos en estaciones meteorológicas convencionales, con errores entre ± 5 y 30 W m2. Además, los modelos lineales más utilizados para estimar Rn en superficie utilizan para su desarrollo la radiación solar incidente y el albedo, lo que conlleva a una limitación para su uso durante los períodos nocturnos. Para estimar G/Rn a escala regional se ha demostrado que es posible hacerlo a partir de datos de satélite una vez que la temperatura de la superficie (LST) se obtiene por ejemplo, a partir de SEVIRI a bordo del satélite METEOSAT. Los coeficientes de correlación entre la temperatura estimada por SEVIRI y la medida en campañas de campo sobre matorral y viñas tienen valores altamente significativos (R2 ≥ 0,94). Los modelos utilizados para seleccionar los datos de entrada para el modelo neuronal propuesto para estimar Rn se describen en detalle, así como la metodología utilizada para estimar el flujo de calor en superficie y a partir de Rn. Para la modelización y estimación de Rn también se utilizaron modelos lineales multivariantes y modelos neuronales (Perceptrón Multicapa), que utilizan como datos de entrada los datos de alta resolución temporal y espacial de los flujos radiativos en el TOA (techo de la atmósfera), obtenidos a partir de la sinergia entre los sensores GERB y SEVIRI. Los parámetros de entrada utilizados en el modelo neuronal (ángulo solar cenital, flujo de radiación de onda corta y onda larga), son los proporcionados por GERB, un instrumento diseñado exclusivamente para hacer mediciones del balance de radiación de la Tierra en TOA. Los resultados obtenidos demuestran que los modelos neuronales son una poderosa herramienta para la modelización de procesos climáticos

Rede Nacional de Cuidados Continuados e Tempo de Internamento dos Doentes com Acidente Vascular Cerebral 2010-2011

INTRODUCTION: The National Post Hospital Care Project was created to provide a continuity of care after hospitalization or to functionally dependent people. Currently there is a great difficulty in the integration of patients. The objective of this paper is to compare the impact of the referral to the Project versus being discharged home, in the length of stay of stroke patients between 2010 and 2011. MATERIAL AND METHODS: Retrospective study of patients admitted to the Neurology Infirmary A and Stroke Unit of Coimbra's University Hospital, in 2010 and 2011. The cases analyzed were 1 209, featuring demographic data, length of stay, Rankin Score (mRS) and destination after discharge. The data was analyzed comparing the two years concerning the length of stay of stroke patients referred to the Project and those discharged home, given the their Rankin Score. RESULTS: In 2011, the number patients referred to the National Post Hospital Care Project was higher, 23.5% compared to 21.4%. The length of stay for the same Rankin Score of the patients referred to National Post Hospital Care Project, remained higher than those discharged home: for a Rankin Score of 1: 11, versus 26 days for the Project; Rankin Score 2: 13, versus 29 days for the project; Rankin Score 3: 13, versus 23 days for the Project; Rankin Score 4: 17, to 33 days for the Project, Rankin Score 5: 27, versus 39 days to the Project. After comparison between the length of stay of patient discharged of and those referred to the National Post Hospital Care Project, it was estimated that the referral represented an hospitalization excess of 1 718 days in 2010 and 1 198 days in 2011

The essential foundations of argumentation in science education: a study from the units, taxonomic elements and quality of the argument

This study aims to understand the argumentative discussions established by children during the development of Inquiry-based Activities in Science Education (IBASE). For this, we elaborated two instruments of analysis of the argumentation. The first, called Taxonomical Elements of Scientific Argumentation (TESA), seeks to characterize the structure and progression of the argument and the second, called Quality of the Modified Argument, aims to rank the argument at different levels. To exemplify the use of these instruments, the children's and young people's argument was analyzed in a scientific workshop on "Flight of the Airplanes". As a result, the categories evidenced by TESAs cannot be thought of as isolated and autonomous units, but rather as a continuum of evolution, characterizing in discursive movements from the simplest to the most complex

Biofeedback na atividade eletromiográfica dos músculos do assoalho pélvico em gestantes

BACKGROUND: Maintaining continence is among the functions of the pelvic floor muscles (PFM) and their dysfunction can cause urinary incontinence (UI), which is a common occurrence during pregnancy and the puerperal period. Pelvic floor muscle training (PFMT), therefore, is important during pregnancy, although most women perform the muscle contractions unsatisfactorily. OBJECTIVES: This study is an exploratory analysis of the results of three electromyographic (EMG) activity biofeedback sessions in pregnant women. METHODS: The study sample included 19 nulliparous women with low risk pregnancies. The participants performed three sessions of EMG biofeedback consisting of slow and fast contractions. The average value of the normalized amplitudes of surface electromyography was used to evaluate the results. The linear regression model with mixed effects was used for statistical analysis, with the EMG data normalized by maximum voluntary contraction (MVC). RESULTS: A steady increase in EMG amplitude was observed during each contraction and by the end of the biofeedback sessions, although this difference was only significant when comparing the first tonic contraction of each session (p=0.03). CONCLUSIONS: The results indicate that three sessions of training with biofeedback improved PFM EMG activity during the second trimester in women with low-risk pregnancies. The effectiveness of this protocol should be further investigated in randomized controlled trials.CONTEXTUALIZAÇÃO: Dentre as funções dos músculos do assoalho pélvico (MAPs), pode-se citar a manutenção da continência, sendo que sua disfunção pode causar a incontinência urinária (IU), muito frequente no período gestacional e no puerpério. Diante disso, se faz importante o treinamento dos músculos do assoalho pélvico (TMAP) durante o período gestacional, entretanto grande parte das mulheres realiza a contração dessa musculatura de maneira insatisfatória. OBJETIVOS: Realizar uma análise exploratória dos resultados de três sessões de biofeedback na atividade eletromiográfica em mulheres gestantes. MÉTODOS: Este estudo incluiu 19 gestantes nulíparas com gravidez de baixo risco. Foram realizadas três sessões de biofeedback eletromiográfico compostas por contrações lentas e rápidas, utilizando-se como método de avaliação dos resultados as médias das amplitudes normalizadas da eletromiografia (EMG) de superfície. Para a análise estatística, utilizou-se o modelo de regressão linear com efeitos mistos, sendo que os dados da EMG foram normalizados pela contração voluntária máxima (CVM). RESULTADOS: Após as sessões de biofeedback, constatou-se um aumento crescente na amplitude eletromiográfica a cada contração realizada e a cada sessão, entretanto essa diferença só foi estatisticamente significante para a comparação entre a primeira contração tônica de cada sessão (p=0.03). CONCLUSÕES: Os resultados obtidos indicam que três sessões de treinamento com biofeedback melhoraram a atividade eletromiográfica dos MAPs em gestantes de baixo risco no segundo trimestre. A efetividade do protocolo necessita ser futuramente investigada em estudo randomizado controlado.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Enhancing the longevity and functionality of Ti-Ag dry electrodes for remote biomedical applications: a comprehensive study

This study aims to evaluate the lifespan of Ti-Ag dry electrodes prepared using flexible polytetrafluoroethylene (PTFE) substrates. Following previous studies, the electrodes were designed to be integrated into wearables for remote electromyography (EMG) monitoring and electrical stimulation (FES) therapy. Four types of Ti-Ag electrodes were prepared by DC magnetron sputtering, using a pure-Ti target doped with a growing number of Ag pellets. After extensive characterization of their chemical composition and (micro)structural evolution, the Ti-Ag electrodes were immersed in an artificial sweat solution (standard ISO-3160-2) at 37 °C with constant stirring. Results revealed that all the Ti-Ag electrodes maintained their integrity and functionality for 24 h. Although there was a notable increase in electrical resistivity beyond this timeframe, the acquisition and transmission of (bio)signals remained viable for electrodes with Ag/Ti ratios below 0.23. However, electrodes with higher Ag content (Ag/Ti = 0.31) became insulators after 7 days of immersion due to excessive Ag release into the sweat solution. This study concludes that higher Ag/Ti atomic ratios result in heightened corrosion processes on the electrode’s surface, consequently diminishing their lifespan despite the advantages of incorporating Ag into their composition. This research highlights the critical importance of evaluating electrode longevity, especially in remote biomedical applications like smart wearables, where electrode performance over time is crucial for reliable and sustained monitoring and stimulation.This research was funded by the European Regional Development Fund (ERDF) through the Operational Programme for Competitiveness and Internationalization (COMPETE 2020) under Portugal 2020, in the framework of the NanoStim (POCI-01-0247-FEDER-045908) and NanoID (NORTE-01-0247-FEDER-046985) Projects

Low-cost irradiance sensors for irradiation assessments inside tree canopies.

The solar irradiation that a crop receives is directly related to the physical and biological processes that affect the crop. However, the assessment of solar irradiation poses certain problems when it must be measured through fruit inside the canopy of a tree. In such cases, it is necessary to check many test points, which usually requires an expensive data acquisition system. The use of conventional irradiance sensors increases the cost of the experiment, making them unsuitable. Nevertheless, it is still possible to perform a precise irradiance test with a reduced price by using low-cost sensors based on the photovoltaic effect. The aim of this work is to develop a low-cost sensor that permits the measurement of the irradiance inside the tree canopy. Two different technologies of solar cells were analyzed for their use in the measurement of solar irradiation levels inside tree canopies. Two data acquisition system setups were also tested and compared. Experiments were performed in Ademuz (Valencia, Spain) in September 2011 and September 2012 to check the validity of low-cost sensors based on solar cells and their associated data acquisition systems. The observed difference between solar irradiation at high and low positions was of 18.5% ± 2.58% at a 95% confidence interval. Large differences were observed between the operations of the two tested sensors. In the case of a-Si cells based mini-modules, an effect of partial shadowing was detected due to the larger size of the devices, the use of individual c-Si cells is recommended over a-Si cells based mini-modules