627 research outputs found
Differential effects of theta/beta and SMR neurofeedback in ADHD on sleep onset latency
Recent studies suggest a role for sleep and sleep problems in the etiology of attention deficit hyperactivity disorder (ADHD) and a recent model about the working mechanism of sensori-motor rhythm (SMR) neurofeedback, proposed that this intervention normalizes sleep and thus improves ADHD symptoms such as inattention and hyperactivity/impulsivity. In this study we compared adult ADHD patients (N = 19) to a control group (N = 28) and investigated if differences existed in sleep parameters such as Sleep Onset Latency (SOL), Sleep Duration (DUR) and overall reported sleep problems (PSQI) and if there is an association between sleep-parameters and ADHD symptoms. Secondly, in 37 ADHD patients we investigated the effects of SMR and Theta/Beta (TBR) neurofeedback on ADHD symptoms and sleep parameters and if these sleep parameters may mediate treatment outcome to SMR and TBR neurofeedback. In this study we found a clear continuous relationship between self-reported sleep problems (PSQI) and inattention in adults with- and without-ADHD. TBR neurofeedback resulted in a small reduction of SOL, this change in SOL did not correlate with the change in ADHD symptoms and the reduction in SOL only happened in the last half of treatment, suggesting this is an effect of symptom improvement not specifically related to TBR neurofeedback. SMR neurofeedback specifically reduced the SOL and PSQI score, and the change in SOL and change in PSQI correlated strongly with the change in inattention, and the reduction in SOL was achieved in the first half of treatment, suggesting the reduction in SOL mediated treatment response to SMR neurofeedback. Clinically, TBR and SMR neurofeedback had similar effects on symptom reduction in ADHD (inattention and hyperactivity/impulsivity). These results suggest differential effects and different working mechanisms for TBR and SMR neurofeedback in the treatment of ADHD
Predicting sex from brain rhythms with deep learning
We have excellent skills to extract sex from visual assessment of human faces, but assessing sex from human brain rhythms seems impossible. Using deep convolutional neural networks, with unique potential to find subtle differences in apparent similar patterns, we explore if brain rhythms from either sex contain sex specific information. Here we show, in a ground truth scenario, that a deep neural net can predict sex from scalp electroencephalograms with an accuracy of >80% (p < 10-5), revealing that brain rhythms are sex specific. Further, we extracted sex-specific features from the deep net filter layers, showing that fast beta activity (20-25 Hz) and its spatial distribution is a main distinctive attribute. This demonstrates the ability of deep nets to detect features in spatiotemporal data unnoticed by visual assessment, and to assist in knowledge discovery. We anticipate that this approach may also be successfully applied to other specialties where spatiotemporal data is abundant, including neurology, cardiology and neuropsychology
Flow Path Resistance in Heterogeneous Porous Media Recast into a Graph-Theory Problem
Acknowledgment is made to the U.S. NSF (EAR-1847689) and the Donors of the American Chemical Society Petroleum Research Fund (59864-DNI9) for partial support of this research. The authors also thank Drs Matthias Willmann, Jefrey Hyman and Markus Holzner for assistance with numerical simulations and insightful discussionsPeer reviewedPublisher PD
Adubação e arranjo de plantas no consórcio milho e braquiária.
A otimização do manejo de milho consorciado com braquiária depende da fertilidade do solo, da densidade de plantas de braquiária e do arranjo de plantas do milho. Avaliaram-se as interações desses fatores e sua influência na produtividade de grãos e da pastagem, em experimento conduzido por duas safras, num fatorial 2x2x3+1, combinando-se duas condições de adubação do milho (para produtividade de 6 ou > 10 t ha-1 de grãos), densidade média ou alta de braquiária ( 30 plantas m-2), três arranjos de plantas de milho (A = 90 cm entre linhas, 5 plantas m-1; B = 45 cm entre linhas, 2,5 plantas m-1; e C = 45 cm entre linhas, 3 plantas m-1) e um tratamento adicional (maior adubação, sem braquiária e arranjo A do milho). A disponibilidade hídrica influenciou as respostas aos tratamentos. Em ano chuvoso, maior adubação resultou em expressivo incremento da produtividade de grãos, independentemente do arranjo de plantas de milho e da presença de braquiária. Em ano com veranico, o ganho do milho, devido à adubação, foi menor e houve efeito prejudicial da maior densidade de braquiária. A produção de matéria seca pela braquiária não apresentou relação direta com a variação na densidade de plantas
Desenvolvimento de mapas de avaliação do desempenho de sistemas fotovoltaicos em diferentes ângulos de inclinação e de azimute
O Brasil, devido as suas dimensóes continentais, apresenta condicóes muito distintas de radiacáo solar e clima, o que toma difícil modelar um sistema foto voltaico baseado em dados que nao sejam locáis. A instalagáo de sistemas foto voltaicos fixos em inclina^oes e orientagoes adequadas é fundamental para otimizar o desempenho energético do mesmo. Este trabalho apresenta e desenvolve mapas de avalia^áo do desempenho de sistemas fotovoltaicos em distintos ángulos de inclinaváo e de azimute considerando diferentes perfis de radiacáo solar. Os mapas de avaliagáo foram desenvolvidos a partir de resultados obtidos de simulagbes computacionais com o software System Advisor Model (SAM) desenvolvido pelo Laboratorio Nacional de Energias Renováveis (NREL) do Departamento de Energia (DOE) dos Estados Unidos. Os mapas desenvolvidos permitem avaliar o desempenho energético de um sistema fotovoltaico genérico em duas regioes com perfis distintos de radia^áo solar.Brazil has very different conditions of solar radiation, which makes it difficult to model a PV system based on data that are not local. The installation of photovoltaic systems with angles of inclination and azimuth appropriate is critical to optimizing the energy performance of the same. This paper presents and develops evaluation maps of performance of photovoltaic systems at different angles of inclination and azimuth considering different profiles of solar radiation. The evaluation maps were developed from the results of computational simulations with System Advisor Model (SAM) that was developed by the National Renewable Energy Laboratory (NREL) of the U.S. Department of Energy (DOE). Developed maps allow assessing the energy performance of a generic PV system into two regions with distinct profiles of solar radiation.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES
Desenvolvimento de mapas de avaliação do desempenho de sistemas fotovoltaicos em diferentes ângulos de inclinação e de azimute
O Brasil, devido as suas dimensóes continentais, apresenta condicóes muito distintas de radiacáo solar e clima, o que toma difícil modelar um sistema foto voltaico baseado em dados que nao sejam locáis. A instalagáo de sistemas foto voltaicos fixos em inclina^oes e orientagoes adequadas é fundamental para otimizar o desempenho energético do mesmo. Este trabalho apresenta e desenvolve mapas de avalia^áo do desempenho de sistemas fotovoltaicos em distintos ángulos de inclinaváo e de azimute considerando diferentes perfis de radiacáo solar. Os mapas de avaliagáo foram desenvolvidos a partir de resultados obtidos de simulagbes computacionais com o software System Advisor Model (SAM) desenvolvido pelo Laboratorio Nacional de Energias Renováveis (NREL) do Departamento de Energia (DOE) dos Estados Unidos. Os mapas desenvolvidos permitem avaliar o desempenho energético de um sistema fotovoltaico genérico em duas regioes com perfis distintos de radia^áo solar.Brazil has very different conditions of solar radiation, which makes it difficult to model a PV system based on data that are not local. The installation of photovoltaic systems with angles of inclination and azimuth appropriate is critical to optimizing the energy performance of the same. This paper presents and develops evaluation maps of performance of photovoltaic systems at different angles of inclination and azimuth considering different profiles of solar radiation. The evaluation maps were developed from the results of computational simulations with System Advisor Model (SAM) that was developed by the National Renewable Energy Laboratory (NREL) of the U.S. Department of Energy (DOE). Developed maps allow assessing the energy performance of a generic PV system into two regions with distinct profiles of solar radiation.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES
Quantitative properties of complex porous materials calculated from X-ray μCT images
A microcomputed tomography (μCT) facility and computational infrastructure developed at the Department of Applied
Mathematics at the Australian National University is described. The current experimental facility is capable of acquiring
3D images made up of 20003 voxels on porous specimens up to 60 mm diameter with resolutions down to 2 μm. This
allows the three-dimensional (3D) pore-space of porous specimens to be imaged over several orders of magnitude. The
computational infrastructure includes the establishment of optimised and distributed memory parallel algorithms for image
reconstruction, novel phase identification, 3D visualisation, structural characterisation and prediction of mechanical and
transport properties directly from digitised tomographic images.
To date over 300 porous specimens exhibiting a wide variety of microstructure have been imaged and analysed. In this
paper, analysis of a small set of porous rock specimens with structure ranging from unconsolidated sands to complex carbonates
are illustrated. Computations made directly on the digitised tomographic images have been compared to laboratory
measurements. The results are in excellent agreement. Additionally, local flow, diffusive and mechanical properties can
be numerically derived from solutions of the relevant physical equations on the complex geometries; an experimentally
intractable problem. Structural analysis of data sets includes grain and pore partitioning of the images. Local granular
partitioning yields over 70,000 grains from a single image. Conventional grain size, shape and connectivity parameters
are derived. The 3D organisation of grains can help in correlating grain size, shape and orientation to resultant physical
properties. Pore network models generated from 3D images yield over 100000 pores and 200000 throats; comparing the
pore structure for the different specimens illustrates the varied topology and geometry observed in porous rocks. This
development foreshadows a new numerical laboratory approach to the study of complex porous materials
On-the-fly Uniformization of Time-Inhomogeneous Infinite Markov Population Models
This paper presents an on-the-fly uniformization technique for the analysis
of time-inhomogeneous Markov population models. This technique is applicable to
models with infinite state spaces and unbounded rates, which are, for instance,
encountered in the realm of biochemical reaction networks. To deal with the
infinite state space, we dynamically maintain a finite subset of the states
where most of the probability mass is located. This approach yields an
underapproximation of the original, infinite system. We present experimental
results to show the applicability of our technique
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