211 research outputs found
Análise comparativa de dois métodos de repovoamento com coelho-bravo: método tradicional e translocação
O coelho-bravo é uma espécie-chave na Península Ibérica. O seu declínio é uma das principais ameaças à conservação dos predadores que se especializaram nesta espécie. Este estudo foi desenvolvido no âmbito de um projeto que visa aumentar a disponibilidade de recursos tróficos para um casal de águia de Bonelli. O principal objetivo do estudo consiste na comparação de resultados entre dois métodos de repovoamento com coelho-bravo empregando exemplares procedentes de cativeiro, a saber: (1) translocação de coelhos previamente sujeitos a um período de 4 semanas de habituação/aclimatação; (2) repovoamento seguindo o protocolo tradicional. Para o efeito, procedeu-se à monitorização, com recurso a telemetria, de um grupo de nove coelhos (um macho e oito fêmeas) translocados e de um grupo de seis coelhos (dois machos e quatro fêmeas) colocados num cercado tradicional de repovoamento. Todos os coelhos foram rádio localizados até se verificar uma das três seguintes situações: separação da coleira do seu portador, morte do portador da coleira ou esgotamento da pilha de alimentação da coleira. Concluiu-se que o primeiro método de repovoamento é muito mais eficaz, exibindo os coelhos translocados maior capacidade para explorarem os recursos existes, naturais e artificialmente disponibilizados, e menor vulnerabilidade à predação. De facto, enquanto ao fim de um mês e meio todos os coelhos libertados através do método tradicional de repovoamento tinham morrido, ao fim de quatro meses e vinte dias, três das oito coelhas translocadas ainda se encontravam vivas; ABSTRACT: The wild rabbit is a key species in the Iberian Peninsula. Its decline is a major threat to the conservation of predators specialized on this species. This study was developed as part of a project to increase the availability of food resources for a couple of Bonelli's eagle. The main goal of the study lies in the comparison of results between two methods of wild rabbit restocking through the employment of specimens coming from captive, namely: (1) translocation of rabbits previously subjected to a period of 4 weeks of accustomedness / acclimatization, (2) restocking by following the traditional protocol. For this purpose, we proceeded to monitoring, using telemetry, a group of nine translocated rabbits (one male and eight female) and a group of six rabbits (two males and four females) which were placed in a traditional repopulation pen. All rabbits were located by radio until one of the following three situations occurred: separation between collar and rabbit, collar holder's death or depletion of the collar’s battery. It was concluded that the first method of restocking is much more effective, because translocated rabbits show a greater capacity of exploiting the existing resources, natural and artificial, and are less vulnerability to predation. In fact, while all rabbits released through the traditional restocking method died after one and a half months, three out of eight translocated females were still alive after four months and twenty days
Analysis of the anti-islanding protection of induction generators connected to electric power distribution systems
Orientador: Walmir de Freitas FilhoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de ComputaçãoResumo: Em redes de distribuição, ilhamento ocorre quando parte da rede elétrica é desconectada do restante do sistema da concessionária, mas continua a ser energizada por um ou mais geradores distribuídos conectados a ela. Esta ocorrência deve ser evitada porque coloca em risco a segurança de pessoas e equipamentos. Diversos trabalhos têm sido desenvolvidos na análise do comportamento ilhado e da proteção antiilhamento de geradores síncronos e de geradores não-rotativos conectados via conversores eletrônicos. No entanto, pouca atenção tem sido dada aos casos envolvendo geradores de indução, sejam eles geradores duplamente alimentados ou com rotor tipo gaiola de esquilo. Portanto, o objetivo desta dissertação de mestrado é investigar o comportamento destes geradores durante ilhamentos, bem como analisar a eficiência dos relés baseados em medidas de freqüência e tensão para a realização de proteção antiilhamento. A ferramenta empregada para análise da proteção antiilhamento é a zona de não-detecção, a qual é definida como a região no espaço de desbalanço de potência reativa versus desbalanço de potência ativa em que o sistema de proteção antiilhamento não consegue detectar a situação de ilhamento dentro do tempo especificado. Tais zonas foram obtidas através de numerosas simulações de transitórios eletromagnéticos utilizando o programa PSCAD/EMTDCAbstract: In distribution systems, islanding occurs when part of the electric system is disconnected from the remaining utility system, but continues to be fed by one or more distributed generators operating in the island. This occurrence should be avoided as it represents a safety risk to equipment and customers. There have been several research papers which analyze the islanding behavior and the anti-islanding protection of synchronous generators and non-rotating generators connected to the grid using electronic converters. Nonetheless, little attention has been spent to analyze the situations involving induction generators, either doubly-fed generators or squirrel-cage generators. Therefore, the objective of this dissertation is to investigate the behavior of these generators during islanded operation, as well as analyze the efficiency of anti-islanding protection schemes based on frequency and voltage relays. The analysis is conducted by using the non-detection zone, which is defined in the active versus reactive power imbalance space where the anti-islanding protection fails. These zones were determined by numerous electromagnetic transient simulations by using the software PSCAD/EMTDCMestradoEnergia EletricaMestre em Engenharia Elétric
Identifying functional subdivisions in the medial frontal cortex
[Excerpt] The medial frontal cortex (MFC) is
thought to be involved in numerous sensorimotor,
cognitive, and affective processes.
This region is commonly divided
into separate subregions, including the
anterior cingulate cortex, supplementary
motor area (SMA), and the pre-SMA, orbitofrontal
cortex, and anterior frontal
poles (Amodio and Frith, 2006). The activity
of the MFC is highly heterogeneous.
Activation of the MFC is reported in
many fMRI studies, and it is associated
with a variety of processes, including action
monitoring (Bonini et al., 2014), response
conflict (Gehring and Fencsik,
2001), reward (Taylor et al., 2006), and
decision-making (Kahnt et al., 2011). This
creates uncertainty in the identification of
specific psychological states associated
with patterns of activity in the MFC, referred
as the reverse inference problem. (...)P. S. M. was supported by PhD-iHES Program FCT Fellowship Grant PDE/BDE/113601/2015. R.M. was supported by PhD-iHES Program FCT Fellowship Grant PDE/BDE/113604/2015. P.M. was supported by Fundação Calouste Gulbenkian Contract Grant P-139977 (“Better mental health during ageing based on temporal prediction of individual brain ageing trajectories”)
A EDUCAÇÃO ESTATÍSTICA COMO FERRAMENTA MATEMÁTICA PARA O ENSINO FUNDAMENTAL
Este artigo tem por objetivo verificar se a Estatística está sendo abordada pelos livros didáticos do nono ano do ensino fundamental adotados pelas escolas municipais de Pouso Alegre – MG. Para tanto, esta pesquisa foi fundamentada nos Parâmetros Curriculares Nacionais que preveem a necessidade da inserção desse conteúdo no currículo, devido à alta demanda social e à falta de profissionais que tenham conhecimento nesta área.. Como metodologia, foi priorizada a pesquisa bibliográfica através da análise dos livros didáticos, tendo como foco a inserção dos temas estatísticos. Pode-se, por meio dessa pesquisa, afirmar que todas as coleções pesquisadas apresentam em seu conteúdo de nono ano os temas relacionados, embora varie de coleção para coleção a maneira como cada tema é abordado. Foram encontrados também exercícios contextualizados apresentando situações do cotidiano, como forma de despertar o interesse do aluno no aprendizado. Assim, os resultados demonstram a preocupação dos autores em atualizar os temas de maior relevância no ensino fundamental, que é a base para a futura vida acadêmica do aluno. Verifica-se, portanto, que os livros utilizados estão de acordo com os PCN na abordagem do tema desta pesquis
The impact of normalization and segmentation on resting state brain networks
Graph theory has recently received a lot of attention from the neuroscience community as a method to represent and characterize brain networks. Still, there is a lack of a gold standard for the methods that should be employed for the preprocessing of the data and the construction of the networks, as well as a lack of knowledge on how different methodologies can affect the metrics reported. We used graph theory analysis applied to resting-state functional Magnetic Resonance Imaging (rs-fMRI) to investigate the influence of different node-defining strategies and the effect of normalizing the functional acquisition on several commonly reported metrics used to characterize brain networks. The nodes of the network were defined using either the individual FreeSurfer segmentation of each subject or the FreeSurfer segmented MNI (Montreal National Institute) 152 template, using the Destrieux and sub-cortical atlas. The functional acquisition was either kept on the functional native space or normalized into MNI standard space. The comparisons were done at three levels: on the connections, on the edge properties and on the network properties levels. Our results reveal that different registration and brain parcellation strategies have a strong impact on all the levels of analysis, possibly favoring the use of individual segmentation strategies and conservative registration approaches. In conclusion, several technical aspects must be considered so that graph theoretical analysis of connectivity MRI data can provide a framework to understand brain pathologies.(undefined
Central autonomic nervous system response to autonomic challenges is altered in patients with a previous episode of Takotsubo Cardiomyopathy
Aims:
Takotsubo cardiomyopathy is an intriguing disease characterized by acute transient left ventricular dysfunction usually triggered by an episode of severe stress. The excessive levels of catecholamines and the overactivation of the sympathetic system are believed to be the main pathophysiologic mechanisms of Takotsubo cardiomyopathy, but it is unclear whether there is a structural or functional signature of the disease. In this sense, our aim was to characterize the central autonomic system response to autonomic challenges in patients with a previous episode of Takotsubo cardiomyopathy when compared with a control group of healthy volunteers.
Methods and results:
Functional magnetic resonance imaging (fMRI) was performed in four patients with a previous episode of Takotsubo cardiomyopathy (average age of 6712 years) and in eight healthy volunteers (average age of 66 +/- 5 years) while being submitted to different autonomic challenges (cold exposure and Valsalva manoeuvre). The fMRI analysis revealed a significant variation of the blood oxygen level dependent signal triggered by the Valsalva manoeuvre in specific areas of the brain involved in the cortical control of the autonomic system and significant differences in the pattern of activation of the insular cortex, amygdala and the right hippocampus between patients with Takotsubo cardiomyopathy and controls, even though these regions did not present significant volumetric changes.
Conclusion:
The central autonomic response to autonomic challenges is altered in patients with Takotsubo cardiomyopathy, thus suggesting a dysregulation of the central autonomic nervous system network. Subsequent studies are needed to unveil whether these alterations are causal or predisposing factors to Takotsubo cardiomyopathy.The work was supported by the European Commission (FP7): ‘SwitchBox’ (Contract HEALTH-F2-2010-259772) and ‘MyHealth’ project (Contract DoIT-13853), and by Fundação para a Ciência e Tecnologia (project FCT-ANR/NEU-OSD/0258/2012 Portuguese North Regional Operational Program (ON.2 – O Novo Norte)) under the National Strategic Reference Framework (QREN), through the European Regional Development Fund (FEDER). PM is supported by a ‘SwitchBox’ fellowship and RM by a FCT-ANR/NEU-OSD/0258/2012 fellowship
Analysis of polymerization time on abrasive wear of dental resins
An evaluation was made of the abrasive wear of six composite thermofixed dental resins subjected to different polymerization times. The method of evaluation was based on sharpness measurements to quantify the abrasive wear resistance of the resins. To this end, a test bench was built, consisting of a rotating porcelain cylinder that wears out a resin-coated cylinder placed above it, thus causing vertical displacement of the contact as the wear progresses. The values of vertical displacement, i.e., the input variables, were read and recorded by means of a computer program to obtain the sharpness values. These data indicated that the resins displayed different behaviors as a function of the polymerization times applied, reinforcing the importance of using a practical and rapid method of analysis in order to ensure that the behavior of new materials is fully understood before they are launched on the market.FAPES
Análise de cruzamentos dialélicos parciais para teor de tanino em sorgo
With the objective of estimating genetic compounds for averages in tannin content in sorghum [Sorghum bicolor (L.) Moench], an experiment of partial diallel crosses (5 x 4) was carried out. Inbreds with no tannin were identified as parents of group 1 and parents of group 2 the inbreds with tannin. The results showed that phenol content in the grain varied between 0.110% and 0.290% equivalent tannic acid for the inbreds of group 1 and 1.869% and 2.753% for the group 2. The hybrids showed values between 0.897% and 2.067%. It was shown that the genetic control of tannin content was mainly additive. The estimatives for combining ability allow to identify inbreds which can be used in plant breeding programs, intending to obtain sorghum with no tannin or with tannin in the grain.Este trabalho foi desenvolvido com o objetivo de estimar componentes genéticos de médias para teor de tanino em sorgo [Sorghum bicolor (L.) Moench], utilizando-se cruzamentos dialélicos parciais (5 x 4). Definiu-se como parentais do grupo 1 as linhagens com ausência de tanino e parentais do grupo 2 aquelas com presença de tanino. Os resultados mostraram que o teor de fenóis variou entre 0,110% e 0,290% equivalente ácido tânico nas linhagens do grupo 1 e de 1,869% a 2,753% nas linhagens do grupo 2. Os híbridos apresentaram valores entre 0,897% e 2,067%. Evidenciou-se que o controle genético do teor de tanino no grão foi predominantemente aditivo. As estimativas das capacidades de combinações permitiram identificar linhagens a serem utilizadas em programas de melhoramento genético por hibridação que objetivassem selecionar sorgo com presença ou ausência de tanino no grão
Evolution of the root anatomy of 'Saracura' maize in successive selection cycles
Este trabalho teve como objetivo verificar as modificações nas características anatômicas radicularesrelacionadas à hipoxia, durante 18 ciclos de seleção da variedade de milho (Zea mays) BRS 4154 Saracura,adaptada a áreas sujeitas a alagamento. A variedade BR 107 e o híbrido simples BRS 1010, suscetíveis ao alagamento, foram utilizados como controle. As diferentes cultivares foram submetidas a alagamentos intermitentes, a cada dois dias, durante dois meses. As amostras radiculares foram preparadas e analisadas em microscopia óptica. Em relação ao grupo controle e aos ciclos anteriores de seleção, a BRS 4154 teve aumento na formação de aerênquima, diminuição do córtex, diminuição do diâmetro dos vasos, diminuição da camada subepidérmica, aumento na espessura do floema e epiderme. Os sucessivos ciclos de seleção melhoraram as características do milho 'Saracura' e sua tolerância a ambientes alagados.This work aimed to verify the modifications in the root anatomical characteristics related to hypoxia, along 18 selection cycles of the maize (Zea mays) cultivar BRS 4154 Saracura, adapted to areas subject to flooding. Cultivars not tolerant to fooding, BR 107 and the simple hybrid BRS 1010, were used as controls. The different cultivars were subjected to intermittent soil waterlogging every two days for two months. The root samples were prepared and analyzed through light microscopy. Compared to the controls group and to early selection cycles, BRS 4154 had increased development of aerenchyma, decreased cortex thickness, decreased metaxylem diameter, decreased subepidermal layer, and increased epidermis and phloem thickness. The successive selection cycles improved 'Saracura' maize characteristics and its tolerance to flooding environments
Bisphosphonate treatment and dental implants : a systematic review
To analyze articles that studied patients submitted to diphosphonates therapy and who received dental implants before, during or after bisphosphonate (BP) treatment, compared to healthy patients, analyzing the increase of failure and loss of implants or bisphosphonate related osteonecrosis of the jaw (BRONJ) incidence. The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement was used in this study. The clinical question in ?PICO? format was: In patients under bisphosphonate therapy, do dental implants placement, compared to healthy patients, increase the failure and loss of implants or bisphosphonate related osteonecrosis of the jaw incidence? PubMed/MEDLINE was searched for articles published up until April 15, 2015 using a combination of MeSH terms and their Entry terms. The search resulted in 375 articles. After selection according to the eligibility criteria, 15 studies fulfilled were included (eight retrospective, one prospective and six case series), with a total of 1339 patients analyzed, 3748 implants placed, 152 loss of implants and 78 cases of BRONJ. Due to the lack of randomized clinical trials looking at this theme, further studies with longer follow-up are needed to elucidate the remaining questions. Thus, it is wise to be careful when planning dental implant surgery in patients undergoing bisphosphonate therapy because of the risk of developing BRONJ as well as occurring failure of implant. Moreover, complete systemic condition of the patient must be also taking into considering when such procedures are performed
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