Background: Motor neuron diseases (MND) represent a group of disorders that evolve with inexorable muscle weakness and medical management is based on symptom control. However, deeper characterization of non-motor symptoms in these patients have been rarely reported. Methods: This cross-sectional study aimed to describe non-motor symptoms in MND and their impact on quality of life and functional status, with a focus on pain and sensory changes. Eighty patients (31 females, 55.7 AE 12.9 years old) with MND underwent a neurological examination, pain, mood, catastrophizing and psychophysics assessments [quantitative sensory testing (QST) and conditioned pain modulation (CPM)], and were compared to sex-and age-matched healthy controls (HC). Results: Chronic pain was present in 46% of patients (VAS = 5.18 AE 2.0). Pain of musculoskeletal origin occurred in 40.5% and was mainly located in the head/neck (51%) and lower back (35%). Neuropathic pain was not present in this sample. Compared to HC, MND patients had a lower cold detection threshold (p < 0.002), and significantly lower CPM scores (4.9 AE 0.2% vs. 22.1 AE 0.2%, p = 0.012). QST/CPM results did not differ between MND patients with and without pain. Pain intensity was statistically correlated with anxiety, depression and catastrophism, and spasticity scores were inversely correlated with CPM (q = À0.30, p = 0.026). Conclusions: Pain is frequently reported by patients with MNDs. Somatosensory and CPM changes exist in MNDs and may be related to the neurodegenerative nature of the disease. Further studies should investigate the most appropriate treatment strategies for these patients. Significance: We report a comprehensive evaluation of pain and sensory abnormalities in motor neuron disease (MND) patients. We assessed the different pain syndromes present in MND with validated tools, and described the QST and conditioned pain modulation profiles in a controlled design.
Optimal scheduling is a requirement for microgrids to participate in current and future energy markets. Although the number of research articles on this subject is on the rise, there is a shortage of papers containing detailed mathematical modeling of the distributed energy resources available in a microgrid. To address this gap, this paper presents in detail how to mathematically model resources such as battery energy storage systems, solar generation systems, directly controllable loads, load shedding, scheduled intentional islanding, and generation curtailment in the microgrid optimal scheduling problem. The proposed modeling also includes a methodology to determine the availability cost of battery and solar systems assets. Simulations were carried out considering energy prices from an actual time-of-use tariff, costs based on real market data, and scenarios with scheduled islanding. Simulation results provide support to validate the proposed model. Data illustrate how energy arbitrage can reduce microgrid costs in a time-of-use tariff. Results also show how the microgrid’s self-sufficiency and the storage system’s capacity can impact the microgrid’s energy bill. The findings also bring out the need to consider the scheduled islanding event in the day-ahead optimization for microgrids.
Microgrids (MGs) have increasingly attracted the attention of researchers, government officials, and electricity companies for the values and services they can add to the grid. They can operate independently as a single controllable unit in a coordinated way while connected or islanded, which make them suitable to integrate the growing amount of distributed energy resources (DERs) into the distribution network (DN). An active distribution network with high penetration of DERs could be redefined into a collection of microgrids in different layers, pooling their resources together to enhance the grid's performance in the sense of electricity as a service. However, enabling a microgrid-based power system infrastructure poses challenges concerning operation and control. In this paper, a comprehensive overview of research topics regarding microgrid operation are shown in a hierarchical or stratified manner, looking for a holistic vision of a microgrid-based distribution system. First, multi-objective optimization within one microgrid is formulated aiming to minimize costs and maximize battery life is presented. Second, the interaction among MGs, DERs and the DN was modeled using the OPF technique to represent the operation of the grid as a whole. HIGHLIGHTS Efforts in research to enable a microgrid-based power system infrastructure are shown. In a first level, by the optimization of the assets within a microgrid via multi-objective optimization; In a second level, by the optimization of microgrid while connected to the main grid via OPF analysis; In a third level, by the optimization of multi-microgrids connected together and to the grid. Alternatively, by considering decentralized energy markets as an integration approach. Machado, M.; et al.
são os mais indicados para simular formas de onda que representem um canal com desvanecimento Rayleigh. Este trabalho tem a pretensão de ser útil para pesquisadores atuantes na área de modelagem e simulação de sistemas atuais de comunicação móvel.
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