195 research outputs found
The role that choice of model plays in predictions for epilepsy surgery
This is the final version. Available on open access from Nature Research via the DOI in this recordMathematical modelling has been widely used to predict the effects of perturbations to brain networks. An important example is epilepsy surgery, where the perturbation in question is the removal of brain tissue in order to render the patient free of seizures. Different dynamical models have been proposed to represent transitions to ictal states in this context. However, our choice of which mathematical model to use to address this question relies on making assumptions regarding the mechanism that defines the transition from background to the seizure state. Since these mechanisms are unknown, it is important to understand how predictions from alternative dynamical descriptions compare. Herein we evaluate to what extent three different dynamical models provide consistent predictions for the effect of removing nodes from networks. We show that for small, directed, connected networks the three considered models provide consistent predictions. For larger networks, predictions are shown to be less consistent. However consistency is higher in networks that have sufficiently large differences in ictogenicity between nodes. We further demonstrate that heterogeneity in ictogenicity across nodes correlates with variability in the number of connections for each node.Engineering and Physical Sciences Research Council (EPSRC)Medical Research Council (MRC)Epilepsy Research UKWellcome Trus
The Role of Excitability and Network Structure in the Emergence of Focal and Generalized Seizures
This is the final version. Available on open access from Frontiers Media via the DOI in this recordData Availability Statement:
The code and synthetic networks generated are available upon request.Epileptic seizures are generally classified as either focal or generalized. It had been traditionally assumed that focal seizures imply localized brain abnormalities, whereas generalized seizures involve widespread brain pathologies. However, recent evidence suggests that large-scale brain networks are involved in the generation of focal seizures, and generalized seizures can originate in localized brain regions. Herein we study how network structure and tissue heterogeneities underpin the emergence of focal and widespread seizure dynamics. Mathematical modeling of seizure emergence in brain networks enables the clarification of the characteristics responsible for focal and generalized seizures. We consider neural mass network dynamics of seizure generation in exemplar synthetic networks and we measure the variance in ictogenicity across the network. Ictogenicity is defined as the involvement of network nodes in seizure activity, and its variance is used to quantify whether seizure patterns are focal or widespread across the network. We address both the influence of network structure and different excitability distributions across the network on the ictogenic variance. We find that this variance depends on both network structure and excitability distribution. High variance, i.e., localized seizure activity, is observed in networks highly heterogeneous with regard to the distribution of connections or excitabilities. However, networks that are both heterogeneous in their structure and excitability can underlie the emergence of generalized seizures, depending on the interplay between structure and excitability. Thus, our results imply that the emergence of focal and generalized seizures is underpinned by an interplay between network structure and excitability distribution.Medical Research Council (MRC)Epilepsy Research UKEngineering and Physical Sciences Research Council (EPSRC)Wellcome TrustInnovate U
Computational modelling in source space from scalp EEG to inform presurgical evaluation of epilepsy
This is the author accepted manuscript. The final version is available on open access from Elsevier via the DOI in this recordObjective: The effectiveness of intracranial electroencephalography (iEEG) to inform epilepsy surgery depends on where iEEG electrodes are implanted. This decision is informed by noninvasive recording modalities such as scalp EEG. Herein we propose a framework to interrogate scalp EEG and determine epilepsy lateralization to aid in electrode implantation. Methods: We use eLORETA to map source activities from seizure epochs recorded from scalp EEG and consider 15 regions of interest (ROIs). Functional networks are then constructed using the phase-locking value and studied using a mathematical model. By removing different ROIs from the network and simulating their impact on the network’s ability to generate seizures in silico, the framework provides predictions of epilepsy lateralization. We consider 15 individuals from the EPILEPSIAE database and study a total of 62 seizures. Results were assessed by taking into account actual intracranial implantations and surgical outcome. Results: The framework provided potentially useful information regarding epilepsy lateralization in 12 out of the 15 individuals (p=0.02, binomial test). Conclusions: Our results show promise for the use of this framework to better interrogate scalp EEG to determine epilepsy lateralization. Significance: The framework may aid clinicians in the decision process to define where to implant electrodes for intracranial monitoring.Medical Research CouncilEpilepsy Research UKEngineering and Physical Sciences Research Council (EPSRC)Wellcome TrustEngineering and Physical Sciences Research Council (EPSRC)Innovate UKEuropean Union’s Horizon 2020Alzheimer's SocietyMedical Research Counci
COMPUTAÇÃO UBÍQUA: ESTADO DA ARTE E OPORTUNIDADES DE PESQUISA PARA A ÁREA DE NEGÓCIOS
Ubiquitous computing refers to the third wave of computing, an emerging theme in scientific research, which has interdisciplinary characteristics. The objective of this study is to map the field of research in ubiquitous computing, especially to explore the research focusing on ubiquitous computing applied to the organizational context and business, identifying opportunities for future research. The data presented here result of an analysis of academic references (2,165 articles) in the database Web of Science (WoS). We used the WoS analytical tools and content analysis of the titles and abstracts of the articles, and/or full articles analysis when they were available. The results of analysis indicate that scientific research on ubiquitous computing had its development especially since the last decade, since then being strongly linked to the areas of Computer Science, Telecommunications and Engineering, still rare are the studies that relate it to management and businesses. In this sense, knowledge gaps were identified during the construction of this article, leading to a proposed agenda for future research that may expand the understanding, with an organizational perspective, of the applications of ubiquitous computing.A computação ubíqua refere-se à terceira onda da computação, um tema emergente na pesquisa científica, que tem características interdisciplinares. O objetivo deste trabalho é mapear o campo de pesquisa em computação ubíqua, especialmente buscando explorar os estudos que enfoquem a computação ubíqua aplicada ao contexto organizacional e a negócios, identificando oportunidades para pesquisa futura. Os dados aqui apresentados resultam de uma análise de referências acadêmicas (2.165 artigos) por meio de consulta à base de dados Web of Science (WoS). Como recursos de análise foram utilizadas a própria ferramenta analítica da WoS, além de análise de conteúdo dos títulos e abstracts dos artigos, e/ou dos artigos completos quando disponíveis. Os resultados da análise indicam que a pesquisa científica sobre computação ubíqua teve seu desenvolvimento especialmente a partir da última década, estando desde então fortemente associada às áreas de Ciência da Computação, Telecomunicações e Engenharias, sendo ainda incipientes os estudos que a relacionam à área de negócios. Nesse sentido, lacunas de conhecimento foram identificadas ao longo da construção deste artigo, levando à proposição de uma agenda para pesquisas futuras que possam ampliar a compreensão, sob a perspectiva organizacional, das aplicações da computação ubíqua.
Plaster Layout Process in Civil Works with a Focus on Clean Production
The constant expansion of civil construction and the increasing use of plaster gives rise to a solid waste generation problem causing difficulties for the disposal or reuse of this material. The generation of plaster waste represents an economic problem, with serious consequences and impacts. In order to contribute to sustainability, this study sought to evaluate the reduction of plaster waste in an apartment construction project, employing the layout method. With the adequate arrangement of plates, a reduction of 4.41% in the use of plaster could be obtained, This reduction will consequently result in the minimization of waste from civil works, bringing invaluable economic and environmental benefits
Condições meteorológicas de outubro-novembro-dezembro de 2022, prognóstico climático para o trimestre janeiro-fevereiro-março de 2023 e recomendações fitotécnicas para vinhedos.
O Boletim Agrometeorológico da Serra Gaúcha - Edição Janeiro de 2023, apresenta uma retrospectiva das condições meteorológicas registradas em 2022 pelas estações de Veranópolis (CEFRUTI/DDPA/SEAPDR) e de Bento Gonçalves (Inmet/Embrapa Uva e Vinho). Descreve as condições que caracterizaram o trimestre outubro-novembro-dezembro, apresenta o prognóstico climático para janeiro-fevereiro-março de 2023, bem como analisa as respostas das videiras e traz recomendações fitotécnicas para a viticultura da Serra Gaúcha. De acordo com os autores, a primavera de 2022 foi a terceira, em sequência, sob atuação do fenômeno La Niña, com consequente ocorrência de uma situação de restrição hídrica, associada com temperaturas do ar abaixo da média histórica. Confira, nesta publicação, de que forma estes eventos interferiram na polinização e formação das bagas e como os produtores devem proceder diante das possíveis condições de estiagem.Jan
Adsorption and incorporation of the zinc oxide nanoparticles in seeds of corn: germination performance and antimicrobial protection
The treatments of the seeds are important procedures applied by the agronomical area to improve the culture yield. From these procedures the micronutrients are available for the seeds before and during the germination stages. One high challenge is make efficient these treatment processes and to ensure the adsorption and the incorporation of these micronutrients in the seeds and to improve its performance in the germination phase. In this work studies explored the optimization of the incorporation process and the characteristics of the zinc oxide clusters adsorbed on the surface of the seed. The results were associated with the agronomic responses during the germinations stages of the seeds of corn. The seeds were treated in suspensions containing different concentrations of nanoparticles of zinc oxide and during different treatment times. The adsorptions in the corn surface and the absorption of the nanoparticles for the inner of the seeds were studied together with its antibacterial characteristics and correlated with the germinations indicators. The results showed that is possible to incorporate nanoparticles of zinc oxide in inner of the seeds of corn and improve the germinations indicators. Antibacterial protection was aggregated on the seeds of corn. It´s possible to incorporate 0.280 mg of zinc oxide nanoparticle per seed mass in inner of seeds with the optimal treatment conditions with nanoparticle concentration of 50 mg/L in the suspension and with treatment time of 180 minutes. With the optimal treatment concentration the normal plant percentage increase of 2.70% in relationship to the seeds not treated
Edição Julho 2021: condições meteorológicas de abril a junho de 2021, prognóstico climático para o trimestre julho-agosto-setembro e recomendações fitotécnicas para vinhedos.
Maio e junho de 2021 foram caracterizados por temperaturas do ar médias mensais abaixo das médias históricas na região da Serra Gaúcha. Em maio, os desvios negativos ocorreram para média das temperaturas médias, máximas e mínimas, enquanto que, em junho, os desvios negativos estiveram associados, especialmente, às temperaturas médias e máximas. No trimestre abril-maio-junho de 2021 foram contabilizadas 191 Horas de Frio (HF: número de horas nas quais a temperatura do ar é igual ou inferior a 7,2ºC) em Veranópolis e 171 HF em Bento Gonçalves. De modo geral, o outono e o início do inverno de 2021 permitiram uma regularidade fisiológica de resposta na ativação do estado de dormência, pois as temperaturas do ar permaneceram baixas e relativamente constantes, o que repercutiu no acúmulo de horas de frio e favoreceu uma maior profundidade e uniformidade do estado de dormência. Com prognóstico climático de temperaturas próximas às médias nos meses de julho e agosto, espera-se que ainda haja ocorrência de horas de frio, de modo que a superação da dormência em 2021 tende a ser plena para maioria dos genótipos. Além disso, diante do prognóstico de chuvas ligeiramente acima da média, especialmente em setembro, a brotação inicial das plantas também tende a ser estimulada. Com as condições favoráveis para brotação no inverno e início da primavera de 2021 (soma de frio e disponibilidade hídrica), o produtor deve dar atenção à poda. Na poda, o número de gemas por planta deve ser ajustado para regularizar e harmonizar a relação entre a capacidade produtiva e o vigor de crescimento dos ramos da videira. Na questão de fitossanitária, é importante que a poda seja seguida de proteção dos cortes (ferimentos) para reduzir o avanço de podridões por meio de aplicação de calda ou pasta bordalesa, ou pincelamento de tinta plástica misturada com fungicida diretamente no corte. Além disso, é recomendada a esterilização da tesoura de poda com hipoclorito, especialmente no intervalo entre plantas, para evitar a disseminação de doenças na linha de plantiobitstream/item/224549/1/BolAgromet-Julho2021.pd
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