1,966 research outputs found

    Cities in a Pandemic: Evidence from China

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    This paper studies the impact of urban density, city government efficiency, and medical resources on COVID-19 infection and death outcomes in China. We adopt a simultaneous spatial dynamic panel data model to account for (i) the simultaneity of infection and death outcomes, (ii) the spatial pattern of the transmission, (iii) the inter-temporal dynamics of the disease, and (iv) the unobserved city- and time-specific effects. We find that, while population density increases the level of infections, government efficiency significantly mitigates the negative impact of urban density. We also find that the availability of medical resources improves public health outcomes conditional on lagged infections. Moreover, there exists significant heterogeneity at different phases of the epidemiological cycle

    Characterization of Adenocarcinoma\u27s Autofluorescence Properties Using Multiexcitation Analysis Method

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    General purpose of this research is to get an early cancer detection method based on the properties of optical analysis between normal and adenocarsinoma tissue using the multiexcitation autofluorescence method. Observation of autofluorescence properties was done on the biopsy sample of adenocarcinoma tissues, GR mice transplanted by adenocarsinoma, and cell culture SM 1. Excitation on tissue was done by using  the lamp Light Emitting Diode (LED) at some visible light wavelength range. This research obtained that the value of Intensity Auto fluorescence (IAF) at range red wavelength of cells and adenocarsinoma tissues tend to lower compared to the cells normal tissues if its were excited by blue LED. On the contrary, the value of IAF at infra red wavelength from cells and carcinoma tissues tend to higher compared to the cells and normal tissues if its were excited by red LED

    Abordagem da história da ciência na construção de um terrário, numa perspetiva de educação para o desenvolvimento sustentável

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    Mestrado em Ensino de Biologia e Geologia no 3º Ciclo do Ensino Básico e no Ensino SecundárioEm Portugal, avanços têm-se feito notar no que toca à tecnologia, o que leva a que novas aptidões e competências sejam desenvolvidas pelos cidadãos de forma a adaptarem-se à Era da informação. Para tal, é necessário que os alunos saiam já bem preparados das escolas de modo a que as suas aprendizagens atendam a essas mudanças, pois o ensino também implica mudança, evolução e crescimento, não só por parte dos estudantes mas também dos professores, das escolas e de todos os órgãos associados. Desta forma, vários métodos poderão ser implementados nas salas de aulas e um deles é a abordagem à História da Ciência. O presente trabalho investigativo procurou conhecer quais as aprendizagens, comportamentos e atitudes que os alunos desenvolveram ao longo das aulas, dando a conhecer os contributos que a construção de um terrário, através da História da Ciência, pode levar à educação de cidadãos informados, numa perspetiva de Educação para o Desenvolvimento Sustentável. A abordagem foi aplicada a alunos do 8.º ano, na disciplina de Ciências Naturais, utilizando várias técnicas e instrumentos de recolha de dados, nomeadamente, a observação, a análise documental e questionário. O recurso à construção e utilização de um material didático-pedagógico e a abordagem à História da Ciência, permitiram cativar o interesse dos alunos e centraliza-los no processo de ensino e de aprendizagem, no qual o aluno tem o principal papel. Dessa forma, foi possível averiguar como se contextualizam as aprendizagens através da abordagem utilizada, recolher e descrever as perspetivas dos alunos e em desenvolver as aprendizagens, comportamentos e atitudes, numa perspetiva de Educação para o Desenvolvimento Sustentável.In Portugal, advances have been made when it comes to Technology, which leads to new skills and competences to be developed by citizens in order to adapt to the Information age. To this end, it is necessary that students need to be well prepared when they conclude their studies, so that their acquired knowledge could meet these changes, for the teaching also implies changes, evolution and growth, not only by students but also by teachers, schools and all the associated teaching groups. This way, various methods can be implemented in the classroom and one of them is the approach to the History of Science. This research work was aimed to know which learnings, behaviors and attitudes that students developed during the lessons, so that it could be possible to publish the contribution of the construction of a terrarium, based in the History of Science, leading to the education of informed citizens, in a perspective of an Education for Sustainable Development. The approach was applied to 8th grade students, in the discipline of Natural Sciences, using various techniques and data collection instruments, like observation, documental analysis and a questionnaire. Building and using didactic-pedagogic material and applying History of Science knowledge, allowed to captivate the students' interest and it helped centralizing them in the process of teaching and learning, in which the student has the main role. Thus, it was possible to find out how to contextualize the learning through the used approaches, to collect and describe the perspectives of the students and developing the learning subject, behaviors and attitudes on a perspective of Education for the Sustainable Development

    Dimensionality reduction-based building recognition

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    Object recognition is being paid more and more attention in computer vision research and a variety of algorithms have been put forward to enhance the recognition performance. However, building recognition, a relatively specific recognition task, is still at a preliminary stage of development, because the challenging task includes rotation, scaling, illumination changes, occlusion, etc. A building recognition scheme is proposed in this paper, which integrates biologically-inspired feature extraction and dimensionality reduction. Experiments undertaken on our own constructed building database demonstrate that our proposed scheme can achieve satisfactory results.</p

    Relevance feedback-based building recognition

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    Building recognition is a nontrivial task in computer vision research which can be utilized in robot localization, mobile navigation, etc. However, existing building recognition systems usually encounter the following two problems: 1) extracted low level features cannot reveal the true semantic concepts; and 2) they usually involve high dimensional data which require heavy computational costs and memory. Relevance feedback (RF), widely applied in multimedia information retrieval, is able to bridge the gap between the low level visual features and high level concepts; while dimensionality reduction methods can mitigate the high-dimensional problem. In this paper, we propose a building recognition scheme which integrates the RF and subspace learning algorithms. Experimental results undertaken on our own building database show that the newly proposed scheme appreciably enhances the recognition accuracy. © 2010 SPIE.</p

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    Representative force-distance approach curves recorded at a single (a) CNC, (b) LCNC, and (c) TCNF fibre measured at pH 3.5 and 7.2.</p

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    Representative results of a Gaussian fitting for the (a) height, (b) DMT modulus, (c) adhesion force, and (d) dissipation mapping of PFQNM images of the nanocelluloses obtained in PBS solution. (DOCX)</p

    Experimental details for material synthesis, protocol of the experimental setups and measurements.

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    (DOCX)</p
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