Motores de propulsão em veículos elétricos: tipos, características e perspetivas de evolução

Os sistemas de propulsão baseados em motores síncronos de ímanes permanentes (MSIP) e motores de indução (MI) têm sido as principais opções para veículos híbridos (VH) e elétricos (VE). As limitações das reservas e os elevados custos das terras-raras (constituinte essencial dos ímanes permanentes (IP)) têm motivado o interesse por motores sem IP ou com menores quantidades de terras-raras. Várias configurações têm vindo a ser desenvolvidas e/ou aperfeiçoadas, com vista a ultrapassar as limitações dos MI, sendo que a otimização do seu projeto também tem sido alvo de atenção. De modo não exaustivo, o objetivo deste artigo é incidir sobre os tipos de motores atualmente aplicados na propulsão elétrica. No final, apresenta-se uma breve referência às principais tecnologias emergentes.info:eu-repo/semantics/publishedVersio

Morphological and electrophysiological properties of pyramidal-like neurons in the stratum oriens of Cornu ammonis 1 and Cornu ammonis 2 area of Proechimys

AbstractProechimys (Rodentia: Echimyidae) is a neotropical rodent of the Amazon region that has been successfully colonized in the laboratory and used for experimental medicine. Preliminary studies indicated that Proechimys (casiragua) rodents express an atypical resistance to developing a chronic epileptic condition in common models of temporal lobe epilepsy. Moreover, previous investigation of our laboratory described a remarkably different Proechimy's cytoarchitecture organization of the hippocampal CA2 subfield. In the present study, we investigated the intrinsic neuronal properties and morphological characteristics of the Proechimys's hippocampal pyramidal neurons of the CA1 and CA2 areas. A comparative approach was performed using neurons recorded in Wistar rats. A striking finding in Proechimys rodents was the presence of large pyramidal-like neurons throughout the stratum oriens from CA2 to CA1 area. In order to confirm such distinctive feature of the Proechimys's hippocampus, we performed Nissl staining and immunohistochemistry for neurofilament protein SM311. CA2 pyramidal neurons in the stratum pyramidale of Proechimys exhibited a significantly higher input resistance and lower time constant when compared to corresponding cell groups in the same area of the Wistar rat's. This newly identified population of pyramidal-shaped neurons in stratum oriens of Proechimys exhibited distinct electrophysiological and morphological properties. This included larger capacitance, lower input resistance, larger rheobase, long latency to first action potential and slower firing frequency. In addition, the apical dendrites of these neurons were oriented in parallel to apical dendrites of regular pyramidal neurons in stratum pyramidale. Moreover, these neurons were immunoreactive to SM311 as the majority of the neurons of the pyramidal layer. The functional role of these hippocampal neurons of the rodent Proechimys deserves further investigation

One sixth of Amazonian tree diversity is dependent on river floodplains

Amazonia's floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region's floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon's tree diversity and its function.Naturali

Mapping density, diversity and species-richness of the Amazon tree flora

Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution

Overview of neglected tropical diseases and conditions of the nervous system: past, present and perspectives.

Neglected tropical diseases consist of a group of infectious diseases with the unifying features of being poverty-related, prevalent in tropical and subtropical regions, and absent from the public health agenda in wealthy countries. In the same world regions, there are \u201cneglected conditions\u201d which also have a negative impact on health. The nervous system involvement in neglected tropical diseases and conditions is an especially neglected field of investigation. Yet, neurological impairments in neglected tropical diseases and conditions constitute together a major category of invalidating disorders, which cause profound changes in nervous system function, often associated with severe sequels or late-onset disturbances. Here are highlighted (1) infectious diseases of the nervous system that nowadays, with the advances of vaccines and antibiotic therapy, are becoming forgotten (2), those belonging to still ravaging neglected tropical diseases, and (3) knowledge perspectives. It is time for clinical and basic neuroscience to be at the forefront and take up the fight against neglected tropical diseases and conditions, and provide means for better management of the patients

Correlation between different interbody grafts and pseudarthrosis after anterior cervical discectomy and fusion compared with control group: systematic review

Cervical spine degenerative disease is one of the main causes of myelopathy. Anterior cervical discectomy and fusion (ACDF) is the most common surgical procedure used to treat cervical myelopathy. Therefore, it is important to study pseudarthrosis rates after ACDF and correlate them with the graft used. Methods: We performed a systematic review to evaluate the relationship between pseudarthrosis after ACDF and the interbody graft used. Results: A total of 3732 patients were evaluated in 46 studies. The mean age of the included patients was 51.5 ± 4.18 years (range, 42–59.6 years). ACDF is most often perforemd as single-level surgery and the level most impaired is C5-C6. The use of titanium cages, zero profile, recombinant human bone morphogenetic protein 2, and carbon cages was seen as a protective factor for pseudarthrosis compared with the autograft group (control group); with an odds ratio of 0.29, 0.51, 0.03, and 0.3, respectively; the results were statistically relevant. The use of polyetheretherketone, poly(methyl methacrylate), and trabecular metal was a risk factor for development of pseudarthrosis compared with the control group, with an odds ratio of 1.7, 8.7, and 6.8, respectively; the results were statistically relevant. Radiologic follow-up was an important factor for the pseudarthrosis rate; paradoxically, a short follow-up (2 years increased the chance of finding pseudarthrosis. Conclusions: Different types of grafts lead to a significant difference in pseudarthrosis rates. Follow-up time is also an important factor that affects the rate of pseudarthrosis after ACDF134272279sem informaçãosem informaçã

A Possible Role Of The Thalamus In Some Cases Of Sudden Unexpected Death In Epilepsy [9]

[No abstract available]48510361037Betting, L.E., Mory, S.B., Li, L.M., Lopes-Cendes, I., Guerreiro, M.M., Guerreiro, C.A., Cendes, F., Voxel-based morphometry in patients with idiopathic generalized epilepsies (2006) Neuroimage, 32, pp. 498-502Betting, L.E., Mory, S.B., Lopes-Cendes, I., Li, L.M., Guerreiro, M.M., Guerreiro, C.A., Cendes, F., MRI volumetry shows increased anterior thalamic volumes in patients with absence seizures (2006) Epilepsy Behav, 8, pp. 575-580Bonilha, L., Rorden, C., Castellano, G., Cendes, F., Li, L.M., Voxel-based morphometry of the thalamus in patients with refractory medial temporal lobe epilepsy (2005) Neuroimage, 25, pp. 1016-1021Boyko, W.J., Galabru, C.K., McGeer, E.G., McGeer, P.L., Thalamic injections of kainic acid produce myocardial necrosis (1979) Life Sci, 25, pp. 87-98Norden, A.D., Blumenfeld, H., The role of subcortical structures in human epilepsy (2002) Epilepsy Behav, 3, pp. 219-231Scorza, F.A., Sanabria, E.R.G., Calderazzo, L., Cavalheiro, E.A., Glucose utilization during interictal intervals in an epilepsy model induced by pilocarpine: A qualitative study (1998) Epilepsia, 39, pp. 1041-1045Scorza, F.A., Arida, R.M., Priel, M., Calderazzo, L., Cavalheiro, E.A., The contribution of the lateral posterior and anteroventral thalamic nuclei on spontaneous recurrent seizures in the pilocarpine model of epilepsy (2002) Arq Neuropsiquiatr, 60, pp. 572-575Tomson, T., Walczak, T., Sillanpaa, M., Sander, J.W., Sudden unexpected death in epilepsy: A review of incidence and risk factors (2005) Epilepsia, 46, pp. 54-6