High-Resolution Ultrasonic Imaging of Artworks with Seismic Interferometry for Their Conservation and Restoration     

Deyan Draganov  Jürg Hunziker  Karel Heller  Karin Gutkowski  Fernando Marte 《文物保护研究》2018,63(5):277-291

Artworks are an inseparable part of the cultural heritage of societies and provide us with a unique look at cultural developments through time and space. For the best possible conservation, it is paramount to know the constituent materials, condition, and construction techniques of the objects (e.g. painting on wood, fresco, sculpture). Such information is required not only for the surfaces of the objects, but also for the interiors; in the imaging discipline, this is known as depth imaging. Here, we introduce a new method for non-invasive depth imaging as an alternative to traditional non-invasive methods when the latter cannot be used to obtain the required information. We use ultrasonic transverse-wave transmission measurements and turn them into virtual reflection measurements. We achieve this by applying seismic interferometry with active sources. Obtaining reflection measurements by seismic interferometry allows us to apply an advanced imaging technique – prestack depth migration, as used in seismic exploration – to produce a high-resolution depth image of an object. We apply our method to ultrasonic data recorded on a mockup of a painting on a wooden support. We validate our method by comparing our results with an image from X-ray computed tomography.  相似文献   

The impact of the debt crisis on education in Latin America     

Fernando Reimers 《Prospects》1990,20(4):539-554

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Development and initial validation of a scale to measure emotional abuse among school children aged 13-15 years in Sri Lanka     

Fernandopulle S  Fernando D 《Child abuse & neglect》2003,27(10):1087-1099

OBJECTIVE: To develop a scale to measure emotional abuse among school children aged 13-15 years in Sri Lanka that can be used in field settings. METHOD: Emotional abuse was defined based on available literature. Review of literature and discussions with a panel identified 85 items indicating abusive behaviors. Content validity and social acceptability were achieved by getting the views of this same panel and parents, respectively. Item analysis and assessment of validity were carried out based on the responses to the draft instrument by 105 children aged 13-15 years attending a school in an urban slum area. The test-retest reliability of the scale was assessed using the responses from 144 students from a different school. Criterion validity was established by comparing the independent assessments of a psychiatrist for the presence or absence of emotional abuse with the respective scores of the children on the scale. RESULTS: The scale developed to assess emotional abuse included 46 items having a Cronbach alpha of .89. The test-retest reliability was .73. A cutoff score of 95 was identified at a sensitivity of 76.9% and a specificity of 51.4%. CONCLUSIONS: A scale that had a satisfactory level of reliability and validity was socially acceptable, which could be used in school settings in Sri Lanka was developed to enable identification of emotional abuse among school children aged 13-15.  相似文献   

Preconceptions and relations used by children in the construction of food chains     

Leticia Gallegos  Maria E. Jerezano  Fernando Flores 《科学教学研究杂志》1994,31(3):259-272

This study shows two aspects: the predator–prey relations and the preconceptions held by children (9–10 years old) on the construction of food chains. The subjects of the study were 506 fourth-, fifth-, and sixth-grade children from the Mexican education curriculum. The conclusions are based on a single application of an instrument after a lecture in the classroom. The instrument consists of three tasks. The outcome showed that the classification of herbivorous and carnivorous is based in children's preconceptions of size and ferocity. These preconceptions guide the children's selection of the higher-level predator in the construction of a food chain. Another element used by children is the predator-prey relation in the construction of a food chain. The results shed light on the difficulties students have at higher education levels in the resolution of food webs and the relationships with ecosystems.  相似文献   

Knee joint position sense of roller hockey players: a comparative study     

João Venâncio  Diogo Lopes  Joaquim Lourenço  Fernando Ribeiro 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(2):162-168

This study aimed to compare knee joint position sense of roller hockey players with an age-matched group of non-athletes. Forty-three male participants voluntarily participated in this cross-sectional study: 21 roller hockey players (mean age: 23.2 ± 4.2 years old, mean weight: 81.8 ± 9.8 kg, mean height: 180.5 ± 4.1 cm) and 22 age-matched non-athletes (mean age: 23.7 ± 3.9 years old, mean weight: 85.0 ± 6.2 kg, mean height: 181.5 ± 5.0 cm). Knee joint position sense of the dominant limb was evaluated using a technique of open-kinetic chain and active knee positioning. Joint position sense was reported using absolute, relative and variable angular errors. The main results indicated that the group of roller hockey players showed significantly lower absolute (2.4 ± 1.2º vs. 6.5 ± 3.2º, p ≤ 0.001) and relative (1.7 ± 2.1º vs. 5.8 ± 4.4º, p ≤ 0.001) angular errors in comparison with the non-athletes group. In conclusion, the results from this present study suggest that proprioceptive acuity, assessed by measuring joint position sense, is increased in roller hockey players. The enhanced proprioception of the roller hockey players could contribute to injury prevention and improved performance during sporting activities.  相似文献   

REEARCH REPORT     

Antonio J. Hidalgo  I.E.S. San Fernando  I.C.E. José Otero 《International Journal of Science Education》2013,35(7):845-857

This paper addresses the concept of geological time as used by students who face tasks that demand three types of skills: to locate events in time, to order them according to time calendar, and to manage time intervals. The empirical study consisted of asking high school students as well as technical school students to carry out tasks that required the use of the three previously mentioned components. It was found, first, that students frequently used erroneous temporal labels, which shows a lack of knowledge that would allow them to locate events within the context of geobiologic data. Second, the students did not store the representation of a succession of events, but were nevertheless able to create it by means of the deductive use of previous knowledge. Finally, the importance of having an appropriate representation of geological time intervals became patent while observing the students' difficulties in understanding geologic changes.  相似文献   

Representation of the cell and its processes in high school students: An integrated view     

Fernando Flores  Ma Eugenia Tovar  Leticia Gallegos 《International Journal of Science Education》2013,35(2):269-286

This paper presents an integrated view of the ideas and conceptual problems of high school students with respect to the cell, its processes, structure and relation to the functions of multicellular organisms. The theme of cell has divided into eight topics, with a questionnaire for each topic. In these topics, different levels of representation and understanding are distinguished between general considerations about plants and animals, those connected with processes at organ and system levels and, finally, the level of cell processes. Data from 1200 students were analysed. Results show that students have an analogical mechanism that establishes an isomorphism between the representation of the functioning of multicellular organisms of cell processes. A series of problems in understanding was also shown. Results imply that these problems are mainly due to students' lack of differentiation between some processes at organism and organ level, and have important implications for learning this subject. Finally, some suggestions are made for teaching.  相似文献   

Achieving scientific excellence: An exploratory study of the role of emotional and motivational factors     

Liliana S. Araújo  José Fernando A. Cruz  Leandro S. Almeida 《High Ability Studies》2017,28(2):249-264

This study investigates the perceived role of psychological factors in achieving excellence in scientific research. Six outstanding scientists aged 33–42 were interviewed. Data were analyzed inductively resulting in three main dimensions: personality traits and characteristics, psychological skills and processes, and task-specific strategies. Researchers highlighted the importance of emotional factors and motivational processes to achieve and sustain scientific excellence. Flexible coping, emotion regulation, and goal setting were emphasized and described as particularly important in dealing with rejections, setbacks, and team management issues. Persistence and adaptive perfectionism were key individual characteristics which helped participants in nurturing and sustaining motivation. This study suggests that the specific impact of emotional, motivational, and other psychological skills at different stages of excellence development is relevant; yet, further investigation is needed.  相似文献   

The construction of a double-entry table: a study of primary and secondary school students’ difficulties     

Eduardo Marti  Merce Garcia-Mila  Fernando Gabucio  Katerina Konstantinidou 《European Journal of Psychology of Education - EJPE》2011,26(2):215-234

Tables are a presentation format that is commonly used to organize information, and they are widely present in many scenarios of our students’ everyday activities; however, there is a scarcity of studies devoted to their analysis. Some of these studies point out that the organization of data into a double-entry table presents difficulties for primary and secondary school students. The present study analyzes the following: (1) the level of competency of primary and secondary school students in constructing a double-entry table from a set of data and (2) the main difficulties encountered by these students during the task. Our findings showed that the percentage of middle-school students who succeeded in contructing a conventional table was relatively low, and the number did not significantly increase over four school years. A set of difficulties is identified and discussed in terms of cognitive and graphical processes.  相似文献   

A generative theory of relevance     

Fernando Diaz 《Information Retrieval》2010,13(6):689-692

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