2,261 research outputs found

    Reserva cognitiva e demência: uma revisão cientométrica

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    Research into cognitive reserve (CR) and dementia is advancing rapidly. This paper analyses the intellectual structure, emerging trends and relevant shifts in the development of available knowledge. Data collected from the Web-of-Science produced an expanded network of 564 articles and 12,504 citations in the 1998-2017 period. The co-citation network visualized was characterized by a scientometric review using CiteSpace. The results revealed that author Stern Y had the highest number of publications and citations. The network of journals, institutions and countries showed a central-peripheral structure with Neurology, Harvard University and the USA ranked first, respectively. While cognitive reserve remains the most prominent area of research in this field, studies related to functional ability, executive control, mortality data and reserve mechanisms have grown considerably. The identification of critical articles and the development of emerging trends highlights new insights in the area of research, better communicating key findings and facilitating the exploration of data.info:eu-repo/semantics/publishedVersio

    Alzheimer's disease research: a network science approach

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    A limit number of studies have applied bibliometric visualisation to explore the network structure of Alzheimer’s Disease (AD). This paper uses CiteSpace, Carrot and VOSviewer to analyse and visualise the intellectual structure of AD, characterizing, quantitatively and qualitatively, the global scientific outputs, and identifying their trends. The 9,753 articles obtained from the science citation index expanded database (SCI-E), from Web-of-Science, were analysed. The publication data is analysed computationally to identify publication patterns, a rate of growth of publications, types of authorship collaboration, the most productive authors, countries, institutions, journals, keywords, the citation and keyword patterns, the hotspots and the areas of research on the AD. The paper presents a detailed analytical mapping of AD research and charts the progress of discipline with various useful parameters. The authors expect to contribute to the theory, supplying researchers with new tools and enabling practitioners to improve their knowledge about the AD evolution and trends.info:eu-repo/semantics/acceptedVersio

    SuzakuSuzaku X-ray study of the double radio relic galaxy cluster CIZA J2242.8+5301

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    Content: We present the results from SuzakuSuzaku observations of the merging cluster of galaxies CIZA J2242.8+5301 at zz=0.192. Aims. To study the physics of gas heating and particle acceleration in cluster mergers, we investigated the X-ray emission from CIZA J2242.8+5301, which hosts two giant radio relics in the northern/southern part of the cluster. Methods. We analyzed data from three-pointed Suzaku observations of CIZA J2242.8+5301 to derive the temperature distribution in four different directions. Results: The Intra-Cluster Medium (ICM) temperature shows a remarkable drop from 8.5−0.6+0.8_{-0.6}^{+0.8} keV to 2.7−0.4+0.7_{-0.4}^{+0.7} keV across the northern radio relic. The temperature drop is consistent with a Mach number Mn=2.7−0.4+0.7{\cal M}_n=2.7^{+0.7}_{-0.4} and a shock velocity vshock:n=2300−400+700 km s−1v_{shock:n}=2300_{-400}^{+700}\rm\,km\,s^{-1}. We also confirm the temperature drop across the southern radio relic. However, the ICM temperature beyond this relic is much higher than beyond the northern one, which gives a Mach number Ms=1.7−0.3+0.4{\cal M}_s=1.7^{+0.4}_{-0.3} and shock velocity vshock:s=2040−410+550 km s−1v_{shock:s}=2040_{-410}^{+550}\rm \,km\,s^{-1}. These results agree with other systems showing a relationship between the radio relics and shock fronts which are induced by merging activity. We compare the X-ray derived Mach numbers with the radio derived Mach numbers from the radio spectral index under the assumption of diffusive shock acceleration in the linear test particle regime. For the northern radio relic, the Mach numbers derived from X-ray and radio observations agree with each other. Based on the shock velocities, we estimate that CIZA J2242.8+5301 is observed approximately 0.6 Gyr after core passage. The magnetic field pressure at the northern relic is estimated to be 9% of the thermal pressure.Comment: 12 pages, 10 figures, A&A accepte

    Medidas de reserva cognitiva na doença de Alzheimer

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    SCIELO:S2237-60892014000300160 (Nº de Acesso Web of Science)Introduction: Cognitive reserve (CR), a hypothetical construct used to obtain information about cognitive aging, describes the capacity of the adult brain to cope with the effects of neurodegenerative processes. This study evaluated CR using a CR questionnaire (CRQ) and a set of variables (education, leisure activities, lifelong occupation) that inform CR. It also developed a CR index, validated the CRQ, and examined the correlation between the different CR measures. Methods: Functional and neuropsychological capacities of 75 outpatients (mean age: 80.2 years) with a probable AD diagnosis were evaluated. Socio-demographic data and clinical variables were collected. Patients completed two questionnaires: the Participation in Leisure Activities throughout Life questionnaire, and the CRQ. Results: Participants with a greater CR had higher scores in cognitive tests than the elderly with a lower CR. A CR index was developed. CRQ reliability was 0.795 (Cronbach’s alpha). There was a close association between the CR Index and the CRQ. Conclusions: This study found an association between CR measures and education, occupation and participation in leisure activities. The CRQ seems to be a suitable instrument to measure CR in Portuguese populations. INTRODUÇÃO: A reserva cognitiva (RC), um construto usado para informar sobre o envelhecimento cognitivo, descreve a capacidade do cérebro adulto em lidar com os efeitos de processos neurodegenerativos. Este estudo teve como objetivos avaliar a RC com o Questionário de RC (QRC) e através de variáveis (escolaridade, actividades de lazer, ocupação ao longo da vida) que informam sobre a RC; desenvolver um índice de RC; validar o QRC; e correlacionar as diferentes medidas de RC. MÉTODOS: Foram avaliadas as capacidades funcionais e neuropsicológicas de 75 doentes (idade média: 80,2 anos) com diagnóstico de provável doença de Alzheimer, seguidos em ambulatório. Os dados recolhidos incluíram variáveis sócio-demográficas e clínicas. Os pacientes completaram dois questionários: Participação em Atividades de Lazer ao Longo da Vida; e QCR. RESULTADOS: Os doentes com os níveis mais elevados de RC obtiveram os valores mais elevados nos testes cognitivos. Neste estudo foi desenvolvido um IRC. O QRC (versão portuguesa) teve uma fidelidade de 0,795 (alpha de Cronbach) e foi demonstrada uma associação alta entre o IRC e o QRC. CONCLUSÕES: Verificou-se a existência de uma associação entre as medidas de RC e a escolaridade, ocupação e participação em atividades de lazer. O CRQ pode ser considerado um instrumento adequado para medir o CR da população portuguesa

    Reserva cognitiva e a severidade da doença de Alzheimer

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    Alzheimer's disease (AD) is a clinical syndrome caused by neurodegeneration and characterized by a progressive deterioration in cognitive ability and capacity for independent living. Cognitive reserve (CR) describes the capacity of the adult brain to cope with the effects of the neurodegenerative process and to minimize the clinical manifestation of pathology of dementia. The aim of this study was to evaluate the association of CR and the severity of AD. Method: This study was cross-sectional. Functional and neuropsychological abilities of 75 outpatients with probable AD diagnosis were evaluated. Patients completed two questionnaires, "Participation in leisure activities throughout life" and CR Questionnaire. Result: The relationship between Clinical Dementia Rating (CDR) and the level of CR was statistically significant (likelihood ratio (LR), p = 0.015). Conclusion: The level of CR influenced the severity of dementia. This study suggests that AD patients with higher CR may benefit against cognitive decline after diagnosis of AD.info:eu-repo/semantics/publishedVersio

    Abernethy Malformation and Hepatocellular Carcinoma: a Serious Consequence of a Rare Disease

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    Congenital portosystemic shunts (CPSS) are a rare vascular consequence of embryogenetic vascular alterations or the persistence of the fetal circulation elements, first described by John Abernethy in 1793 and classified by Morgan and Superina, into complete and partial portosystemic shunts. Its prevalence to this day has not been defined. We present a patient series of a 44-year-old and 47-year-old man and woman, with this rare congenital malformation and underlining hepatocellular carcinoma (HCC) treatment strategies. Over half of the individuals with CPSS have benign or malignant liver tumours, ranging from nodular regenerative hyperplasia, focal nodular hyperplasia, adenomas, HCC and hepatoblastomas. Additionally, it is known that half of individuals with Abernethy malformation type Ib will develop one or multiple types of tumours. There seems to be a direct association with tumorigenesis and CPSS, which is the primary consequence of absent portal flow. Surgery is the treatment of choice, either as a curative resection or orthotopic liver transplantation if recommended as per the criteria, in which replacing the hepatic parenchyma in the setting of an Abernathy malformation will correct the underlining hyper-arterialisation.info:eu-repo/semantics/publishedVersio

    A Preliminary Study of Image Analysis for Parasite Detection on Honey Bees

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    International Conference Image Analysis and Recognition (ICIAR 2018, Póvoa de Varzim, Portugal

    Background modeling for video sequences by stacked denoising autoencoders

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    Nowadays, the analysis and extraction of relevant information in visual data flows is of paramount importance. These images sequences can last for hours, which implies that the model must adapt to all kinds of circumstances so that the performance of the system does not decay over time. In this paper we propose a methodology for background modeling and foreground detection, whose main characteristic is its robustness against stationary noise. Thus, stacked denoising autoencoders are applied to generate a set of robust characteristics for each region or patch of the image, which will be the input of a probabilistic model to determine if that region is background or foreground. The evaluation of a set of heterogeneous sequences results in that, although our proposal is similar to the classical methods existing in the literature, the inclusion of noise in these sequences causes drastic performance drops in the competing methods, while in our case the performance stays or falls slightly.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    The network science approach in determining the intellectual structure, emerging trends and future research opportunities: An application to Tai chi for older adults

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    This article focuses on the geriatric market segment which is becoming increasingly important as a result of demographic trends and aging populations. Using network science approach, this study maps the structure of knowledge, its changes over time and research opportunities in Tai-chi. Data collected from Web-of-Science and Scopus between 1996-2019 was used to build a network of 2,202 articles and 6,820 authors. The results show Tai-chi represents a small-world network as the majority of the articles were produced among universities and medical schools, displaying a connection between theoretical knowledge and pragmatic applications. The scientific achievements mainly emerge from the USA, China, and UK. The collaborative efforts focused on a giant component and converge on a small area of research. Future opportunities at the intersection of Tai-chi and geriatrics include mindfulness-meditation, osteoarthritis, sleep quality, cardio-respiratory function and pain management. This article provides contributes to the literature on Tai-chi and offers insights into the capabilities of CiteSpace, Vosviewer, Gephi, and Python.info:eu-repo/semantics/publishedVersio
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